μ-LED, μ-LED device, display and method for the same

Abstract

The invention relates to various aspects of a μ-LED or a μ-LED array for augmented reality or lighting applications, in particular in the automotive field. The μ-LED is characterized by particularly small dimensions in the range of a few μm.

Claims

1. A μ-LED arrangement for generating a pixel of a display, comprising: a carrier substrate; at least three μ-LEDs, which are arranged on an assembly side of the carrier substrate; wherein the at least three μ-LEDs are adapted to emit light of different colors transverse to a carrier substrate plane in a direction away from the carrier substrate; a reflector element; wherein the reflector element is spatially arranged on the assembly side of the carrier substrate; wherein the reflector element is covering and laterally surrounding the at least three μ-LEDs and is configured to reflect the light emitted by the at least three μ-LEDs in a second direction of the carrier substrate; wherein the carrier substrate is at least partially transparent so that the light reflected from the reflector element propagates through the carrier substrate and emerges at a display side of the carrier substrate opposite the assembly side; and wherein the at least three μ-LEDs have a common electrical contact on a side of the at least three μ-LEDs facing the reflector element.

2. The μ-LED arrangement according to claim 1, wherein a diffuser layer is provided and/or a reflector material has diffuser particles for scattering the light reflected by the at least three μ-LEDs on a side of the reflector element directed towards the at least three μ-LEDs.

3. The μ-LED arrangement according to claim 1, wherein the reflector element forms an electrical contact of the at least three μ-LEDs.

4. The μ-LED arrangement according to claim 1, wherein the reflector element is configured and shaped such that at least 90% of the light emitted by the at least three μ-LEDs is incident on the assembly side of the carrier substrate at an angle between 45 and 90 degrees relative to the carrier substrate plane.

5. The μ-LED arrangement according to claim 1, wherein a passivation layer is additionally provided for attenuating or eliminating reflections of the light at mesa edges of the at least three μ-LEDs.

6. The μ-LED arrangement according to claim 1, wherein a light absorbing coating is provided on the assembly side and/or the display side of the carrier substrate outside the reflector element.

7. The μ-LED arrangement according to claim 1, wherein a color filter element is arranged on the display side of the carrier substrate opposite the reflector element; and wherein the color filter element allows a primary color spectrum of the at least three μ-LEDs to pass and attenuates deviating color spectra.

8. The μ-LED arrangement according to claim 1, in which a light-shaping structure, in particular a photonic structure is incorporated in or on the carrier substrate, which first and second regions with different refractive indexes are incorporated.

9. The μ-LED arrangement according to claim 1, in which a light-shaping and/or a light-converting structure having a first area and a second area is arranged on the display side of the carrier substrate.

10. The μ-LED arrangement according to claim 1, comprising a converter material surrounding at least one μ-LED of the at least three μ-LEDs and filling a space between the at least one μ-LED and a reflector material.

11. The μ-LED arrangement according to claim 2, wherein the diffuser layer and/or the diffuser particles comprise Al.sub.2O.sub.2 and/or TiO.sub.2.

12. The μ-LED arrangement according to claim 1, wherein the reflector element surrounds the at least three μ-LEDs in a circular, polygonal or parabolic shape.

13. The μ-LED arrangement according to claim 1, wherein the carrier substrate comprises polyamide, a transparent plastic, resin or glass.

14. The μ-LED arrangement according to claim 1, wherein the reflector element is formed as a reflective layer of the at least three μ-LEDs.

15. The μ-LED arrangement according to claim 1, wherein the display side of the carrier substrate has an uneven and/or roughened structure.

16. The μ-LED arrangement according to claim 9, wherein the first area and the second area comprise a converted material.

17. The μ-LED arrangement according to claim 1, further comprising a converter material on the display side of the carrier substrate.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the following section, some of the above-mentioned and summarized aspects are explained in more detail using various explanations and examples.

(2) FIG. 1A shows a diagram illustrating some requirements for so-called μ-displays or micro-displays of different sizes with respect to the field of view and pixel pitch of the μ-display;

(3) FIG. 1B shows a diagram of the spatial distribution of rods and cones in the human eye;

(4) FIG. 1C shows a diagram of the perceptual capacity of the human eye with assigned projection areas;

(5) FIG. 1D is a figure showing the sensitivity of the rods and cones over the wavelength;

(6) FIG. 2A is a diagram illustrating some requirements for micro-displays of different sizes in terms of the field of view and the angle of collimation of a pixel of the μ-display;

(7) FIG. 2B illustrates an exemplary execution of a pixel arrangement to illustrate the parameters used in FIGS. 1A and 2A;

(8) FIG. 3A shows a diagram illustrating the number of pixels required depending on the field of view for a specific resolution;

(9) FIGS. 3B-1 and 3B-2 illustrate a table of preferred applications for μ-LED arrays;

(10) FIG. 4A shows a principle representation of a μ-LED display with essential elements for light generation and light guidance;

(11) FIG. 4B shows a schematic representation of a μ-LED array with similar μ-LEDs;

(12) FIG. 4C is a schematic representation of a μ-LED array with μ-LEDs of different light colors;

(13) FIG. 5A and FIG. 5B show two examples of a structure or beamline and collimation;

(14) FIG. 6 shows a μ-LED pixel where the light emission is already directed by a specially formed reflector material;

(15) FIG. 7 shows an optical pixel element with a spherical reflector element and control electronics according to some aspects of the proposed concept;

(16) FIG. 8 shows a second embodiment of a pixel element with a reflector element designed as a layer and a passivation layer according to some aspects of the proposed concept;

(17) FIG. 9 shows a third embodiment of a pixel element with light-absorbing coatings on a display side and an assembly side of the carrier substrate according to some aspects of the proposed concept;

(18) FIG. 10 forms a pixel element with a roughened display side of the carrier substrate;

(19) FIGS. 11A and 11B are embodiments based on some of the aspects revealed here, with light absorbing layers to minimize crosstalk and a color filter element on the display side of the carrier substrate;

(20) FIGS. 12A and 12B show embodiments of a pixel element with IGZO- or LIPS-based drive electronics on the assembly side of the carrier substrate and optional diffuser layer according to some aspects of the proposed concept;

(21) FIG. 13 shows a cross-section and top view of a pixel cell with three μ-LEDs of different colors and a reflector element;

(22) FIG. 14 shows a method for manufacturing an optical pixel element as described above;

(23) FIG. 15A shows on the left side a cross-sectional view of an exemplary μ-LED and on the right side a perspective view of the optoelectronic device with a photonic structure;

(24) FIG. 15B shows a cross-sectional view of another μ-LED with photonic structure according to some suggested aspects;

(25) FIG. 15C shows on the left side a more detailed cross-sectional view of another optoelectronic device and on the right side a more schematic cross-sectional view of the optoelectronic device;

(26) FIG. 15D is a cross-sectional view of a μ-LED with planar surface and photonic structure;

(27) FIG. 15E shows another embodiment of a μ-LED with photonic structure in cross-sectional view;

(28) FIG. 15F illustrates another embodiment of a μ-LED with photonic structure in cross-sectional view according to some aspects of the proposed concept;

(29) FIG. 16 shows an embodiment of a method for producing one of the structures shown in FIGS. 15D to 15E;

(30) FIG. 17 illustrates a top view and sectional view of an optoelectronic device with a μ-LED and a converter element according to some aspects of simultaneous light shaping and light conversion;

(31) FIG. 18 shows a cross-section through an optoelectronic component in a further version according to some aspects of the proposed concept;

(32) FIG. 19 is a top view and sectional view of another component;

(33) FIG. 20 shows a cross-section through a component with a μ-LED and a converter element according to some aspects of light shaping and light conversion;

(34) FIGS. 21A and 21B show a μ-display with several light-emitting units and a photonic structure in a top view and cross section according to some aspects of the concept presented;

(35) FIGS. 22A and 22B represent a second embodiment of a μ-display with a photonic structure in a top view and cross-section according to some aspects of the presented concept;

(36) FIGS. 23A and 23B show a third embodiment of a μ-display with several μ-LEDs of a photonic structure in a top view and as a cross-section according to some aspects of the presented concept;

(37) FIGS. 24A and 24B are part of a fourth embodiment of a μ-display with a photonic structure in a top view and as a cross-section according to some aspects of the concept presented;

(38) FIGS. 25A and 25B show a fifth embodiment of a μ-display with a photonic structure in a top view and as a cross-section according to some aspects of the presented concept;

(39) FIGS. 26A and 26B illustrate a sixth embodiment of a μ-display with a photonic structure in a top view and as a cross-section according to some aspects of the concept presented;

(40) FIGS. 27A and 27B show a seventh embodiment of a μ-display with a photonic structure in a top view and as a cross section according to some aspects of the presented concept;

(41) FIGS. 28A and 28B illustrate an eighth embodiment of a μ-display of a photonic structure in a top view and as a cross-section;

(42) FIGS. 29A and 29B show a ninth embodiment of a μ-display of a photonic structure in a top view and as a cross-section according to some aspects of the presented concept;

(43) FIG. 30 shows a cross-sectional view of another variant of a device according to the invention;

(44) FIG. 31 shows an arrangement of an optoelectronic component with an emitter unit having a light-emitting surface to which a polarizing element with a three-dimensional photonic structure is applied;

(45) FIG. 32 illustrates a representation of a three-dimensional photonic structure with a large number of spiral-shaped structural elements;

(46) FIG. 33 shows another embodiment of an optoelectronic device with an emitter unit and a polarization element with a three-dimensional photonic structure;

(47) FIG. 34 shows an optoelectronic device with an emitter unit and a three-dimensional photonic structure into which converter material is filled;

(48) FIG. 35 illustrates a perspective view of a first variant of an arrangement with an emitter unit, which has a photonic structure for generating a specific far field;

(49) FIG. 36 shows a sectional view of a second variant of an arrangement with an emitter unit to illustrate further aspects of the proposed principle;

(50) FIG. 37 shows an arrangement of a plurality of arrangements according to the two preceding figures;

(51) FIG. 38 shows a perspective view of a third variant of an arrangement with an emitter unit, which has a photonic structure to generate a defined far field;

(52) FIG. 39 illustrates a block diagram of a surface topography detection system with an arrangement according to one of the preceding figures;

DETAILED DESCRIPTION

(53) Augmented reality is usually generated by a dedicated display whose image is superimposed on reality. Such device can be positioned directly in the user's line of sight, i.e. directly in front of it. Alternatively, optical beam guidance elements can be used to guide the light from a display to the user's eye. In both cases, the display may be implemented and be part of the glasses or other visually enhancing devices worn by the user. Googles™ Glasses is an example of such a visually augmenting device that allows the user to overlay certain information about real world objects. For the Google™ glasses, the information was displayed on a small screen placed in front of one of the lenses. In this respect, the appearance of such an additional device is a key characteristic of eyeglasses, combining technical functionality with a design aspect when wearing glasses. In the meantime, users require glasses without such bulky or easily damaged devices to provide advanced reality functionality. One idea, therefore, is that the glasses themselves become a display or at least a screen on or into which the information is projected.

(54) In such cases, the field of vision for the user is limited to the dimension of the glasses. Accordingly, the area onto which extended reality functionality can be projected is approximately the size of a pair of spectacles. Here, the same, but also different information can be projected on, into or onto the two lenses of a pair of spectacles.

(55) In addition, the image that the user experiences when wearing glasses with augmented reality functionality should have a resolution that creates a seamless impression to the user, so that the user does not perceive the augmented reality as a pixelated object or as a low-resolution element. Straight bevelled edges, arrows or similar elements show a staircase shape that is disturbing for the user at low resolutions.

(56) In order to achieve the desired impression, two display parameters are considered important, which have an influence on the visual impression for a given or known human sight. One is the pixel size itself, i.e. the geometric shape and dimension of a single pixel or the area of 3 subpixels representing the pixel. The second parameter is the pixel pitch, i.e. the distance between two adjacent pixels or, if necessary, subpixels. Sometimes the pixel pitch is also called pixel gap. A larger pixel pitch can be detected by a user and is perceived as a gap between the pixels and in some cases causes the so-called fly screen effect. The gap should therefore not exceed a certain limit.

(57) The maximum angular resolution of the human eye is typically between 0.02 and 0.03 angular degrees, which roughly corresponds to 1.2 to 1.8 arc minutes per line pair. This results in a pixel gap of 0.6-0.9 arc minutes. Some current mobile phone displays have about 400 pixels/inch, resulting in a viewing angle of approximately 2.9° at a distance of 25 cm from a user's eye or approximately 70 pixels/° viewing angle and cm. The distance between two pixels in such displays is therefore in the range of the maximum angular resolution. Furthermore, the pixel size itself is about 56 μm.

(58) FIG. 1A illustrates the pixel pitch, i.e. the distance between two adjacent pixels as a function of the field of view in angular degrees. In this respect, the field of view is the extension of the observable world seen at a given moment. This is because human vision is defined as the number of degrees of the angle of view during stable fixation of the eye.

(59) In particular, humans have a forward horizontal arc of their field of vision for both eyes of slightly more than 210°, while the vertical arc of their field of vision for humans is around 135°. However, the range of visual abilities is not uniform across the field of vision and can vary from person to person.

(60) The binocular vision of humans covers approximately 114° horizontally (peripheral vision), and about 90° vertically. The remaining degrees on both sides have no binocular area but can be considered part of the field of vision.

(61) Furthermore, color vision and the ability to perceive shapes and movement can further limit the horizontal and vertical field of vision. The rods and cones responsible for color vision are not evenly distributed.

(62) This point of view is shown in more detail in FIGS. 1B to 1D. In the area of central vision, i.e. directly in front of the eye, as required for Augmented Reality applications and partly also in the automotive sector, the sensitivity of the eye is very high both in terms of spatial resolution and in terms of color perception.

(63) FIG. 1B shows the spatial density of rods and cones per mm.sup.2 as a function of the fovea angle. FIG. 1C describes the color sensitivity of cones and rods as a function of wavelength. In the central area of the fovea, the increased density of cones (L, S and M) means that better color vision predominates. At a distance of about 25° around the fovea, the sensitivity begins to decrease and the density of the visual cells decreases. Towards the edge, the sensitivity of color vision decreases, but at the same time contrast vision by means of the rods remains over a larger angular range. Overall, the eye develops a radially symmetrical visual pattern rather than a Cartesian visual pattern. A high resolution for all primary colors is therefore required, especially in the center. At the edge it may be sufficient to work with an emitter adapted to the spectral sensitivity of the rods (max. sensitivity at 498 nm, see FIG. 1D and the sensitivity of the eye).

(64) FIG. 1C shows the different perceptual capacity of the human eye by means of a graph of the angular resolution A relative to the angular deviation a from the optical axis of the eye. It can be seen that the highest angular resolution A is in an interval of the angular deviation a of +/−2.5°, in which the fovea centralis 7 with a diameter of 1.5 mm is located on the retina 19. In addition, the position of the blind spot 22 on the retina 19 is sketched, which is located in the area of the optic nerve papilla 23, which has a position with an angular deviation a of about 15°.

(65) The eye compensates this non-constant density and also the so-called blind spot by small movements of the eye. Such changes in the direction of vision or focus can be counteracted by suitable optics and tracking of the eye.

(66) Furthermore, even with glasses, the field of vision is further restricted and, for example, can be approximately in the range of 80° for each lens.

(67) The pixel pitch in FIG. 1A on the Y-axis is given in μm and defines the distance between two adjacent pixels. The various curves C1 to C7 define the diagonal dimension of a corresponding display from 5 mm to approximately 35 mm. For example, curve C1 corresponds to a display with the diagonal size of 5 mm, i.e. a side length of approximately 2.25 mm. For a field of view of approximately 80°, the pixel pitch of a display with a diagonal size of 5 mm is in the range of 1 μm. For larger displays like curve C7 and 35 mm diagonal size, the same field of view can be implemented with a pixel pitch of approximately 5 μm.

(68) Nevertheless, the curves in FIG. 1A illustrate that for larger fields of view, which are preferred for extended reality applications, very high pixel densities with small pixel pitch are required if the well-known fly screen effect is to be avoided. One can now calculate the size of the pixel for a given number of pixels, a given field of view and a given diagonal size of a μ-display.

(69) Equation 1 shows the relationship between dimension D of a pixel, pixel pitch pp, number N of pixels and the edge length d of the display. The distance r between two adjacent pixels calculated from their respective centers is given by
r=d/2+pp+d/2.
D=d/N−pp
N=d/(D+pp)  (1)

(70) Assuming that the display (e.g. glasses) is at a distance of 2.54 cm (1 inch) from the eye, the distance r between two adjacent pixels for an angular resolution of 1 arcminute as roughly estimated above is given by
r=tan(1/60°)*30 mm
r=8.7 μm

(71) The size of a pixel is therefore smaller than 10 μm, especially if some space is required between two different pixels. With a distance, r between two pixels and a display with the size of 15 mm×10 mm, 1720×1150 pixels can be arranged on the surface.

(72) FIG. 2B shows an arrangement, which has a carrier 21 on which a large number of pixels, 20 and 20a to 20c are arranged. Pixels 20 arranged side by side have the pixel pitch pp, while pixels 20a to 20c are placed on carrier 21 with a larger pixel pitch pp. The distance between two pixels is given by the sum of the pixel pitch and half the size for each adjacent pixel. Each of the pixels 20 is configured so that its illumination characteristic or its emission vector 22 is substantially perpendicular to the emission surface of the corresponding LED.

(73) The angle between the perpendicular axes to the emission surface of the LED and the beam vector is defined as the collimation angle. In the example of emission vector 22, the collimation angle of LEDs 20 is approximately zero. LED 20 emits light that is collinear and does not widen significantly.

(74) In contrast, the collimation angle of the emission vector 23 of the LED pixels 20a to 20c is quite large and in the range of approximately 45°. As a result, part of the light emitted by LED 20a overlaps with the emission of an adjacent LED 20b.

(75) The emission of the LEDs 20a to 20c is partially overlapping, so that its superposition of the corresponding light emission occurs. In case the LEDs emit light of different colors, the result will be a color mixture or a combined color. A similar effect occurs between areas of high contrast, i.e. when LED 20a is dark while LED 20b emits a certain light. Because of the overlap, the contrast is reduced and information about each individual position corresponding to a pixel position is reduced.

(76) In displays where the distance to the user's eye is only small, as in the applications mentioned above, a larger collimation angle is rather annoying due to the effects mentioned above and other disadvantages. A user is able to see a wide collimation angle and may perceive displayed objects in slightly different colors blurred or with reduced contrast.

(77) FIG. 2A illustrates in this respect the requirement for the collimation angle in degrees against the field of view in degrees, independent of specific display sizes. For smaller display sizes such as the one in curve C1 (approx. 5 mm diagonal), the collimation angle increases significantly depending on the field of view.

(78) As the size of the display increases, the collimation angle requirements change drastically, so that even for large display geometries such as those illustrated in curve C7, the collimation angle reaches about 10° for a field of view of 100°. In other words, the collimation angle requirements for larger displays and larger fields of view are increasing. In such displays, light emitted by a pixel must be highly collimated to avoid or reduce the effects mentioned above. Consequently, strong collimation is required when displays with a large field of view are to be made available to a user, even if the display geometry is relatively large.

(79) As a result of the above diagrams and equations, one can deduce that the requirements regarding pixel pitch and collimation angle become increasingly challenging as the display geometry and field of view grow. As already indicated by equation 1, the dimension of the display increases strongly with a larger number of pixels. Conversely, a large number of pixels is required for large fields of view if sufficient resolution is to be achieved and fly screens or other disturbing effects are to be avoided.

(80) FIG. 3A shows a diagram of the number of pixels required to achieve an angular resolution of 1.3 arc minutes. For a field of view of approximately 80°, the number of pixels exceeds 5 million. It is easy to estimate that the size of the pixels for a QHD resolution is well below 10 μm, even if the display is 15 mm×10 mm. In summary, advanced reality displays with resolutions in the HD range, i.e. 1080p, require a total of 2.0736 million pixels. This allows a field of view of approximately 50° to be covered. Such a quantity of pixels arranged on a display size of 10×10 mm with a distance between the pixels of 1 μm results in a pixel size of about 4 μm.

(81) In contrast, the table in FIGS. 3B-1 and 3B-2 shows several application areas in which μ-LED arrays can be used. The table shows applications (use case) of μ-LED arrays in vehicles (Auto) or for multimedia (MM), such as automotive displays and exemplary values regarding the minimum and maximum display size (min. and max. size X Y [cm]), the pixel density (PPI) and the pixel pitch (PP [μm]) as well as the resolution (Res.-Type) and the distance of the viewer (Viewing Distance [cm]) to the lighting device or display. In this context, the abbreviations “very low res”, “low res”, “mid res” and “high res” have the following meaning:

(82) very low res pixel pitch approx. 0.8-3 mm

(83) low res Pixel pitch approx. 0.5-0.8 mm

(84) mid res Pixel pitch approx. 0.1-0.5 mm

(85) high res Pixel pitch less than 0.1 mm

(86) The upper part of the table, entitled “Direct Emitter Displays”, shows inventive applications of μ-LED arrays in displays and lighting devices in vehicles and for the multimedia sector. The lower part of the table, titled “Transparent Direct Emitter Displays”, names various applications of μ-LED arrays in transparent displays and transparent lighting devices. Some of the applications of μ-displays listed in the table are explained in more detail below in the form of embodiments.

(87) The above considerations make it clear that challenges are considerable in terms of resolution, collimation and field of view suitable for extended reality applications. Accordingly, very high demands are placed on the technical implementation of such displays.

(88) Conventional techniques are configured for the production of displays that have LEDs with edge lengths in the range of 100 μm or even more. However, they cannot be automatically scaled to the sizes of 70 μm and below required here. Pixel sizes of a few μm as well as distances of a few μm or even less come closer to the order of magnitude of the wavelength of the generated light and make novel technologies in processing necessary.

(89) In addition, new challenges in light collimation and light direction are emerging. Optical lenses, for example, which can be easily structured for larger LEDs and can also be calculated using classical optics, cannot be reduced to such a small size without the Maxwell equations. Apart from this, the production of such small lenses is hardly possible without large errors or deviations. In some variants, quantum effects can influence the behaviour of pixels of the above-mentioned size and have to be considered. Tolerances in manufacturing or transfer techniques from pixels to sub mounts or matrix structures are becoming increasingly demanding. Likewise, the pixels must be contacted and individually controllable. Conventional circuits have a space requirement, which in some cases exceeds the pixel area, resulting in an arrangement and space problem.

(90) Accordingly, new concepts for the control and accessibility of pixels of this size can be quite different from conventional technologies. Finally, a focus is on the power consumption of such displays and controllers. Especially for mobile applications, a low power consumption is desirable.

(91) In summary, for many concepts that work for larger pixel sizes, extensive changes must be made before a reduction can be successful. While concepts that can be easily up scaled to LEDs at 2000 μm for the production of LEDs in the 200 μm range, downscaling to 20 μm is much more difficult. Many documents and literature that disclose such concepts have not taken into account the various effects and increased demands on the very small dimensions and are therefore not directly suitable or limited to pixel sizes well above 70 μm.

(92) In the following, various aspects of the structure and design of μ-LED semiconductors, aspects of processing, light extraction and light guidance, display and control are presented. These are suitable and designed to realize displays with pixel sizes in the range of 70 μm and below. Some concepts are specifically designed for the production, light extraction and control of μ-LEDs with an edge length of less than 20 μm and especially less than 10 μm. It goes without saying, and is even desired, that the concepts presented here can and should be combined with each other for the different aspects. This concerns for example a concept for the production of a μ-LED with a concept for light extraction. In concrete terms, a μ-LED implemented by means of methods to avoid defects at edges or methods for current conduction or current constriction can be provided with light extraction structures based on photonic crystal structures. Likewise, a special drive can also be realized for displays whose pixel size is variable. Light guidance with piezoelectric mirrors can be realized for μ-LEDs displays based on the slot antenna aspect or on conventional monolithic pixel matrices.

(93) In some of the following embodiments and described aspects, additional examples of a combination of the different embodiments or individual aspects thereof are suggested. These are intended to illustrate that the various aspects, embodiments or parts thereof can be combined with each other by the skilled person. Some applications require specially adapted concepts; in other applications, the requirements for the technology are somewhat lower. Automotive applications and displays, for example, may have a longer pixel edge length due to the generally somewhat greater distance to a user. Especially there, besides applications of extended reality, classical pixel applications or virtual reality applications exist. This is in the context of this disclosure for the realization of μ-LED displays, whose pixel edge length is in the range of 70 μm and below, also explicitly desired.

(94) A general illustration of the main components of a pixel in a μ-display is shown schematically in FIG. 4A. It shows an element 60 as a light generating and light emitting device. Various aspects of this are described in more detail below in the section on light generation and processing. Element 60 also includes basic circuits, interconnects, and such to control the illumination, intensity, and, when applicable, color of the pixel. Aspects of this are described in more detail in the section on light control. Apart from light generation, the emitted light must be collimated. For this purpose, many pixels in microdisplays have such collimation functionality in element 60. The parallel light in element 63 is then fed for light guidance into some optics 64, for further shaping and the like. Light collimation and optics suitable for implementing pixels for microdisplays are described in the section on light extraction and light guidance.

(95) The pixel device of FIG. 4A illustrates the different components and aspects as separate elements. An expert will recognize that many components can be integrated into a single device. In practice, the height of a μ-display is also limited, resulting in a desired flat arrangement.

(96) After light has been generated, it must be collimated and directionally coupled out as far as possible. Therefore the following explanations concern different aspects of light extraction.

(97) FIGS. 5A and 5B disclose some principles regarding the collimation and direction of light emitted by individual pixels. FIG. 5A shows a carrier 50, which also acts as a mirror by reflecting all light emitted by the LED 51 arranged on the carrier. Two adjacent LEDs are about 6 μm apart and about 3 μm high. Their diameter is in the range of 6 μm. Each individual pixel emits light similar to a Lambert spotlight. Consequently, they are completely covered with a transparent material with a refractive index of about n=1.5.

(98) A hemisphere 53 of the same material with a radius of approximately 10 μm is arranged on each micropixel. Each hemisphere 53 covers the area of the underlying pixel 51 and extends to about half the distance to the next pixel. Because of the refractive index and geometry, the hemispheres are configured to collimate the light emitted by the individual pixels.

(99) FIG. 5B shows an alternative concept for collimating the light emitted by the pixels. Similar to the above, the micropixels are arranged at equal distances from each other. Between each pixel, a pyramid 52 is placed on the support 50. The pyramids 52 are formed of highly refractive material and have distance D between their tips. The height of the apex of each pyramid is chosen so that light emitted at an angle less than 45° from the light-emitting surface is reflected on the sidewalls of the pyramid as indicated. By using the elements shown in FIG. 5B, light emitted by micropixels 51 can be parallelized to a certain extent, which improves its collimation. However, as the size decreases, it becomes increasingly difficult to shape elements 52 and 53 and to place them directly above the micropixels.

(100) FIG. 6 illustrates an example of a pixel for which, in one aspect, a rear decoupling is provided by shaping the pixel as a hemisphere and surrounding it with reflective material to shape the emitted light. The pixel is shaped as a half-dome within an n-doped first semiconductor material 800. A first contact 801 on a first side of material 800 serves as the n-contact for the corresponding pixel. A second contact 802 can be used for a variety of pixels.

(101) Thus, it is possible to arrange the plurality of pixels next to each other to form a μ-display. Within the half-dome area of the pixel, an active layer 803 is arranged. The active layer is located in the upper third of the half-dome forming the pixel and is formed by a p-doped layer 804 deposited on the n-doped material in the half-dome. Other active layers such as quantum wells or structures mentioned in this disclosure are possible. In order to form the smallest possible region where recombination occurs, a current confinement process can be used. This keeps charge carriers away from the edge and the recombination area becomes smaller.

(102) A reflective layer 805 is applied to the sidewalls and also to the upper surface of the material 800. The p-contact 801 is applied to the reflective layer 805. The reflective layer 805 also includes an insulating layer (not shown) to prevent a short circuit between the p-contact and the material 800. P-contact material 801 is in direct contact with the p-doped layer 804 through a gap in the reflective layer on the half-dome forming the pixel. As a result, the insulating layer on the reflective layer and the gap in the reflective layer causes carrier injection only at the tip of the half-dome. A current broadening layer can also be applied within the p-doped layer 804.

(103) Recombination of charge carriers occurs in the active region 803 Light emitted from the active region towards the side is reflected at the reflective layer towards the output surface TA. The shape of the half-dome is parabolic in some examples. The shape should be chosen to support collinearity for light generated within the active region. In some applications, other elements for guiding light, such as photonic crystal structures or similar are then arranged on the exit surface.

(104) The following aspects deal with a different point of view in contrast to a direct improvement of the directionality of the emitted light. The following examples are intended for the creation of a Lambert radiator. However, it is known by the expert that other shapes on reflector elements influence the beam-shaping. Special designs thus create a μ-LED with rear output, which can be directed at the same time.

(105) FIG. 7 shows an embodiment of a pixel element 10 with a reflector element 18 according to the invention. First of all, a carrier substrate 12 is also provided here, which often has a large number of μ-LEDs 16 arranged next to each other on an assembly side 20 of the carrier substrate 12. The carrier substrate 12 is usually provided with an electronic control unit 24, which is used to control the individual μ-LEDs 16. For this purpose, electrically conductive connections (not shown) may be provided between the control electronics 24 and the individual μ-LEDs 16. In other cases, as shown below, the carrier substrate can also be transparent or have other structures for reshaping the light.

(106) The reflector element 18 here is designed like a dome and surrounds the μ-LED 16 at least on the side where the μ-LED 16 emits light 14. For example, if the μ-LED 16 emits light 14 in a direction away from the carrier substrate 12, this light hits a surface of the reflector element 18 directed towards the μ-LED 16, is reflected there and returned towards the assembly side 20 of the carrier substrate 12. If necessary, the light propagates with refraction at the interface of the assembly side 20 over a cross section of the carrier substrate 12 in the direction of a display side 22 of the carrier substrate 12 and is coupled out there, if necessary with repeated refraction or diffraction.

(107) The reflector element 18 should have the advantageous shape and properties that light 14 is incident at an angle of incidence 26 as perpendicular as possible relative to a carrier substrate plane 28 on the placement side 20 of the carrier substrate 12. Among other things, this should serve to minimize losses due to total reflection within the carrier substrate 12 as well as unfavourable angles when decoupling from display side 22 of carrier substrate 12. This angle of incidence 26 should be as small as possible, also to minimize crosstalk between adjacent pixel elements 10.

(108) FIG. 8 shows another example of a pixel element 10 according to the invention with a reflector element 18 configured as a layer on or around a μ-LED 16. This embodiment variant can be useful in that the reflector element 18 can be processed directly onto a surface of the μ-LED 16, for example as a metallic layer. Various materials can be used for the reflector element 18, such as metallic materials, metal alloys or oxides or other suitable compounds that can be applied using the available manufacturing processes. FIG. 6 shows a similar embodiment, in which the μ-LED is made directly from the same material as the carrier substrate. In addition, the reflector element has a specific shape and design. However, the various aspects of FIG. 6 can also be combined with the embodiments shown in FIGS. 7 to 8, among others, and disclosed here.

(109) In addition, a passivation layer 32 is provided at the mesa edges 30 between the μ-LED 16 and the layer of the reflector element 18. This passivation layer 32 has light-absorbing or at least light-blocking properties so that light 14 emitted by the μ-LED in the direction of the carrier substrate plane 28 or in the direction of the mesa edges 30 is attenuated or absorbed. This is to prevent light 14 from passing over in the direction of an adjacent pixel element 10 and causing crosstalk. In addition, the passivation layers 32 can be configured to cause beam-shaping of the emitted light 14.

(110) FIG. 9 shows a pixel element according to the invention with light-absorbing coatings 34 on a display side 20 and an assembly side 22 of the carrier substrate 12. This embodiment features a spherical reflector element 18 surrounding a μ-LED 16, which is arranged on the placement side 20 of the carrier substrate 12. According to this aspect, the carrier substrate 12 is adapted to be transparent or at least partially transparent so that light 14 can propagate within the carrier substrate 12.

(111) In order to improve the dark impression and contrast of a display, light-absorbing layers 34 are provided according to this embodiment, which are applied here outside the reflector element 18 on the carrier substrate 12 on the assembly side 20 and/or on the display side 22. On the one hand, this can prevent light 14 from being coupled out outside a desired active area of the pixel element. On the other hand, an advantageous effect can be that light 14, which propagates inside the carrier substrate 12, is not coupled out outside the desired area on display side 22, but is absorbed or attenuated. For an observer, the light-absorbing layers 34 can be recognized as clearly inactive or black or dark, and due to the better optical demarcation compared to the active luminous areas, improved contrast properties of a display can be achieved.

(112) FIG. 10 illustrates in a simplified way a further version of a pixel element 10 according to the invention. In its basic structure, pixel element 10 corresponds to the examples already shown in FIGS. 7 to 9. Here, a μ-LED 16 is provided on a carrier substrate 12, which is surrounded by a reflector element 18. By reflecting the light 14 at the reflector element 18, light 14 propagates through the carrier substrate 12 and reaches a display page 22 of the carrier substrate 12.

(113) Here it is desirable that as much of the light 14 that has passed through carrier substrate 12 is coupled out of carrier substrate 12 via display screen 22. Here, a roughened surface 36 can cause an improved out-coupling of light 14. More generally speaking, the surface of the display side 22 comprises a structuring, which has additional microstructures at an angle to each other which deviate in their angle from the alignment parallel to a carrier substrate plane 28 and can thus cause additional out-coupling.

(114) FIG. 11A shows a pixel element 10, according to the invention, with a color filter element 38 on the display side of the carrier substrate 12 and light-absorbing coatings 34. While the basic structure of the pixel element 10 corresponds to a large extent to that of the previous figures, light-absorbing coatings 34 are also provided here, which are provided both on an assembly side 20 and on a display side 22 of the carrier substrate 12 outside an area of the reflector element 18. In addition, a color filter element 38 is provided here, which is arranged on the display side 22 of the carrier substrate 12 opposite the reflector element 18. For example, a red μ-LED can be provided with a corresponding red color filter element 38. The same applies analogueously to green color filter elements 38 together with green μ-LEDs and, for example, to blue color filter elements 38 together with blue μ-LEDs and the respective emitter chips 16. The advantages here are lower reflectivity and an improved black impression. Here, too, the light-absorbing layers 34 absorb unwanted light components 14 that propagate within the carrier substrate 12.

(115) In an alternative embodiment, again with reference to FIG. 11A, element 38 may also be a color conversion element to convert light of a first wavelength to a second wavelength. The light emitted by the μ-LED 16 and reflected by the reflector element 18 strikes the converter element and is converted there. The basic colors can be produced in this way by using different converter dyes.

(116) FIG. 11B shows another example of a pixel element 10, where two adjacent pixel elements 10 are arranged on the carrier substrate. Between these two pixel elements, light absorbing layers 34 are provided on the different surfaces of the carrier substrate. This can be used in particular to minimize crosstalk. Depending on the arrangement and design of the μ-LED 16, there is a gap between the μ-LED 16 and the surrounding reflector element 18, which can act as an aperture or aperture edge. This can mean that light 14 emerges through this aperture at a small angle relative to the carrier substrate plane 28 and can pass through the carrier substrate 12 at an angle in the direction of the adjacent pixel element 10.

(117) To prevent this crosstalk, light-absorbing layers 34 are provided between the two pixel elements 10 and between the two adjacent reflector elements 18, respectively. These can be arranged on an assembly side 20 of the carrier substrate 12, but also on a display side 22 of the carrier substrate 12. The light-absorbing layers 34 attenuate or eliminate the then unwanted light components 14 and can thus improve the contrast of a display.

(118) In FIG. 12A, reference is made to the aspect of the control electronics 24 of a pixel element 10 according to the invention. These may be adapted as part of the carrier substrate 12, with transistor structures, for example, being provided as part of the substrate 12. For the material of the carrier substrate 12, various materials can be considered, such as amorphous silicon, but also IGZO or LIPS. IGZO stands for indium gallium zinc oxide and has partially transparent properties for light and is comparatively inexpensive to manufacture.

(119) If an electronic control unit 24 is designed on the basis of IGZO, it is also conceivable according to an example that the electronic control unit 24 can be arranged within an inner area of a reflector element 18 (not shown here). This possibility is based in particular on the at least partial light transmission of the IGZO material. According to another example, 24 LIPS is used as the basis for the control electronics 24 and LIPS as the material for the carrier substrate 12. LIPS stands for Low Temperature Poly Silicon and can have better electrical properties than IGZO, but with more light absorbing properties.

(120) LIPS can be used for both p-transistors and n-transistors, whereas IGZO is only suitable for p-transistors. An arrangement of the control electronics 24, based on LIPS, must therefore be provided here outside a reflector element 18. A further alternative can be seen in the use of so-called μICs. These are often used together with silicon-based substrates and usually have light-absorbing properties.

(121) A challenge here may lie in miniaturizing these ICs, whereby the electrical performance of the μICs is often higher than that of other variants. Here, too, an arrangement would, according to an example, be made outside an area of a reflector element 18 on the assembly side 20 of the carrier substrate 12. Contacting of the emitter chip 16 can be achieved, for example, via a metallic contact pad on the carrier substrate 12 or via transparent ITO (indium tin oxide).

(122) FIG. 12B shows a pixel element 10 according to the invention with a partial coating of a diffuser layer 40 on the reflector element 18. The special feature of the pixel element 10 shown in this embodiment can be seen in a special embodiment of the reflector element 18. Here, a diffuser layer 40 is provided on the lateral inner surfaces of the reflector element 18 (here especially the area 18B). This diffuser layer 40 is intended to cause an increased deflection of the emitted light 14 and a more advantageous deflection of the light 14 in the direction of the carrier substrate 12. It can be advantageous here to provide a thinner or completely missing diffuser layer 40 in an area 18A of the reflector located vertically directly above the emitter chip.

(123) In particular, this diffuser layer 40 can be made flat or even in this area 18A in order to focus the most direct possible back reflection of light emitted transversely to the carrier substrate plane 28 approximately vertically in the direction of the placement side 20 of the carrier substrate 12. A relatively thin diffuser layer 40 can be sufficient for this purpose, since μ-LEDs, due to their properties and construction, come closer to a Lambertian radiation pattern than previous LED technologies. Materials that can be used for this purpose include Al.sub.2O.sub.3 or TiO.sub.2.

(124) FIG. 13 shows another pixel cell in cross-section and top view. The pixel cell comprises three individual μ-LEDs 16r, 16g and 16b. These are designed to emit the respective basic colors red, green and blue during operation. In this embodiment, the three μ-LEDs are arranged in the corners of a right-angled triangle. However, other arrangements are also possible, for example in a row. Each μ-LED is adapted as a vertical μ-LED, i.e. a common contact is located on the side of the μ-LEDs facing away from the carrier substrate. The μ-LEDs can be individually controlled and can be manufactured, for example, in some versions as shown in FIGS. 49 to 54. Other designs are also conceivable, for example as individual μ-LED modules with or without redundancy. In the illustration on the right, a common transparent cover contact 17 is provided for this purpose, which either completely or at least partially covers the μ-LEDs and thus makes electrical contact. The sidewalls of the μ-LED are insulated and are not connected to the cover electrode 17. In addition, a reflector element 18 is provided which surrounds each of the three μ-LEDs and thus forms a complete pixel.

(125) Light, which is thus emitted in the direction of the reflector element, is reflected by the carrier substrate where it hits a photonic structure 19, which is partly incorporated in the carrier substrate. The photonic structure 19 is designed to redirect the emitted light and emit it as a collimated light beam. Various embodiments of such photonic structures are disclosed in this application, for example in FIG. 17 to 20, 31 to 39 or even 15A to 15C.

(126) The photonic structure can also be omitted depending on the application. For automotive applications, a Lampertian radiation pattern may be more desirable, in which case it is omitted. In the field of Augmented Reality a strong directionality may be desired, which is achieved by the additional photonic structure. In addition to the photonic structure, a converter material can also be provided in addition to the structure or alternatively. In the automotive sector, such directional light applications with white or other colored light are possible.

(127) Finally, FIG. 14 shows a process 100 for the production of a pixel element 10. First, one or more μ-LEDs are attached to one side of a flat carrier substrate. The attachment is preceded by a corresponding transfer. Details are disclosed in this application.

(128) This is followed in step 120 by creating a reflector element, for example as a reflective layer of the μ-LED. According to an example, before step 110, a display side 22 of the carrier substrate 12 is processed to produce a roughening 36 or rough microstructuring of the surface of the display side 22.

(129) One way to reduce the emission angle of μ-LEDs is to indicate structures on the emission surface that reduce the propagation of light parallel to the emission surface. This can be achieved by photonic structures. The photonic crystal structure is basically not limited to a certain material system. The following examples and embodiments will give different ones, which are not limited to a specific design, but are suitable for all embodiments and designs disclosed herein. Furthermore, different semiconductor material systems can be used for the μ-LEDs, especially on GaN, AlInGaP, AlN or InGaAs basis. FIGS. 15A to 15C illustrate different aspects related to the principle of collimation of light by using a photonic crystal.

(130) The exemplary optoelectronic device 700 of FIG. 15A comprises a stack of layers 702, 703 including an active zone 704 for generating electromagnetic radiation, and at least one layer 705 on the main radiation direction, which comprises a photonic crystal structure 706.

(131) For example, layer 702 is a p-doped GaN layer and layer 703 is an n-doped GaN layer. The layer on the underside 701 can be a metallic mirror layer and/or a carrier layer. The growth direction G goes from the top side to the bottom side, or vice versa, and orthogonal to the connecting surface of the layers.

(132) The photonic crystal structure 706 is formed by nanowires with radius r and height h. The wires form a triangular lattice with lattice constant a. However, other lattice geometries such as square lattice are possible. The periodicity and thus the lattice constant a of the photonic crystal structure are such that they are about half the wavelength of the light wavelength to be diffracted. The space between the wires may contain a material, which has a different refractive index than the material of the layer 705. For example, layer 705 may be formed of n-doped GaN. Other materials and SiO.sub.2 are also possible.

(133) The layer 702 can be supplied with an extension 702a, which extends through the layer 703 and reaches into the layer 705 but not into the photonic crystal structure 706 as shown in the lower view of FIG. 15A.

(134) The photonic crystal structure 706 can have the effect of improving the concentration of light passing through it. In particular, the photonic crystal structure 706 can provide a virtual bandgap for a region of wavelengths that are perpendicular to the direction of growth. The photonic crystal structure 706 can block this light. In contrast, light that runs along the direction of growth is basically not disturbed by the photonic crystal structure 706. As shown in the upper view of FIG. 15A, the photonic crystal structure 706 in layer 705 can be generated twice or even more. The structures 706 are separated from each other by the distance D.

(135) Alternatively, a single photonic crystal structure 706 can be fabricated to cover the complete layer 705. In this case, more unit cells of the lattice can be arranged in layer 705, which has a positive effect on the properties of the photonic crystal structure, which depend on the periodicity.

(136) In the exemplary device shown in FIG. 15B, layer 702 is not supplied with an extension. However, layer 703, which is adjacent to layer 705 with crystal structure 706, is provided with a roughened surface, as indicated by projections 703a, 703b, 703c and 703d. The roughened surface can be filled with SiO.sub.2, for example, to fabricate layer 705 with photonic crystal structure 706.

(137) In the exemplary device shown in FIG. 15C, the layer 703 is formed with a wigwam surface roughening 703e. The layer 705 with the photonic crystal structure 706 may contain SiO.sub.2. The photonic crystal structure 706 may be etched into the SiO.sub.2 layer. Air or other material may be in the space between the photonic crystal structure.

(138) The photonic crystal structure 706 covers the complete layer 703 and is placed at a distance H from the wigwam surface roughening 703e of the underlying layer 703.

(139) Layer 701 is a carrier layer, layer 711 can be a compound layer, layer 712 is a mirror layer, especially a silver mirror layer, and layer 713 can be a dielectric layer. A mesa dry etch can be performed during device production and after patterning the photonic crystal structure 706.

(140) The different photonic decoupling structures create a certain roughness and surface structures on the surface, depending on their design. Therefore, the surface should be planarized to facilitate a possibly necessary later transfer. FIGS. 15D to 15F show different aspects of surface planarization according to one of several methods of making photonic structures on a μ-LED.

(141) Generally, a large number of μ-LEDs are first formed in or on a wafer, then their surface is structured and then, if necessary, separated. Modules of μ-LEDs and other designs are part of this application. It is clear from this that the μ-LEDs come in different designs. The following surface treatment is thus independent of the later processing and is suitable for (later isolated) μ-LEDs, μ-LED modules and also pixelated optochips with a plurality of μ-LEDs.

(142) According to FIG. 15D, a μ-LED is epitaxially formed with an active layer in a semiconductor body. The active layer is not shown here. The μ-LED comprises in its surface area, which is covered by the likewise not shown carrier, a non-ordered, i.e. random out-coupling structure A, which is formed from the same semiconductor material as the semiconductor (or parts thereof). The structured surface region therefore adjoins the doped layers. The resulting roughness is smoothed again by applying another transparent material of SiO.sub.2 by means of TEOS (tetraethylorthosilicate) and subsequently planarizing it. The decoupling structure improves the decoupling. It is particularly suitable for the extraction of the light emitted by the active layer. This also reduces optical crosstalk of an adjacent μ-LED with a different wavelength.

(143) The other transparent material shows a low refractive index, especially less than 1.5, which improves the decoupling from the structured area (higher refractive index). Afterwards the other material is removed by CMP process to form the smooth surface 7 of the structured surface area 9. As shown, the removal is either carried out up to the highest areas of the structured area or a surface of the material 5 is generally left over. In this respect, a gradual transition from a high refractive index via the lower refractive index of the material 5 to air results.

(144) In addition to SiO.sub.2 material 5, crown glass with a refractive index of e.g. 1.46, PMMA with a refractive index of e.g. 1.49 and quartz glass with a refractive index of e.g. 1.46 can be used. These refractive indices result at the wavelength 589 nm of the sodium D-line. A refractive index of silicon dioxide, for example, is 1.458.

(145) FIG. 15E shows a second example of a μ-LED with an output structure. To improve light out-coupling, a transparent second material 3 with a high refractive index is applied to the planar or structured surface of the μ-LED and structured in a suitable way.

(146) For example, a suitable second material 3 with a high refractive index greater than 2 is Nb.sub.2O.sub.5 with a refractive index of 2.3. Other usable materials with a high refractive index are for example zinc sulphide with a refractive index of for example 2.37, diamond with a refractive index of for example 2.42, titanium dioxide with a refractive index of for example 2.52, silicon carbide with a refractive index of for example 2.65 and titanium dioxide with a refractive index of for example 3.10. These refractive indices result in particular at the wavelength 589 nm of the sodium D-line. Other materials can also be used.

(147) The structuring of surface area 9 is done, as in FIG. 15D, by creating a random topology on surface area 9. While according to FIG. 15D the random topology is created by directly roughening the surface 7 of the surface region 9 of the semiconductor body comprising a first material 1, according to FIG. 15E the random topology is formed by first depositing the transparent second material 3 and then roughening it.

(148) After the topology has been created, the rough surface is smoothed by applying the transparent material 5 described above to the rough surface and then planarizing it.

(149) FIG. 15F shows a third example of a μ-LED, but this time with an ordered topology. This is explained in detail as in the examples in this application by depositing the transparent second material on the surface. A periodic photonic crystal structure is then introduced into the second transparent material. Alternatively, photonic properties can be achieved by non-periodic structures, especially quasi-periodic or deterministic aperiodic structures.

(150) Alternatively, periodic photonic crystals or non-periodic photonic structures, in particular quasiperiodic or deterministic aperiodic photonic structures, can in principle be directly incorporated into the first material 1 of the semiconductor body without a second material 3.

(151) After the photonic structure has been formed, the interstitial spaces are filled with a transparent material with a lower refractive index. The transparent third material 5, in particular SiO.sub.2, is planarized, resulting in a smooth and even surface. As shown in FIG. 15F, both the surface of material 3 and the interstitial material 5 are flat. However, in an alternative embodiment, the transparent third material 5 extends beyond the structure of material 3, so that the surface is completely formed from material 5. In this way, an out-coupling efficiency can be improved compared to an unmachined surface. A transfer process using stamp technology remains possible because of the smooth and even surface.

(152) FIG. 16 shows an example of a proposed method. In a first step S1 an output structure A is formed on a surface of a μ-LED. This is done by structuring the surface. It is possible to structure the semiconductor material directly or to provide such a structuring after the deposition of a further material. For this purpose, the surface is covered with a photomask, which is then exposed to light, thus defining the structures. The surface is structured by various other processes including various etching steps. In step S2, another transparent material is deposited in the spaces created after etching. The transparent material covers the previously created structure. Subsequently, in step S3 the surface is planarized by CMP or other suitable processes and removed to approximately the height of the structures. The structured μ-LED thus produced can be further processed, separated and transferred.

(153) FIG. 17 shows in a top view and a sectional view a radiation source 6 in the form of a μ-LED and with a layer 2 arranged in a semiconductor substrate 8 of the μ-LED 7, which comprises a photonic structure 4 with a suitable converter material. This is based on the idea of creating a unification of light-shaping and converting structure so that a particularly space-saving arrangement of the individual elements and thus a particularly small design of an optoelectronic component is possible. The structured layer 2 with the converter material forms a converter element 1, whereby the converter material emits converted radiation into a radiation emission area 3 of the radiation source 6 when excited by the excitation radiation emitted by the LED 7.

(154) The structure 4 provided in layer 2 with the converter material is designed in such a way that the converted radiation is emitted exclusively as a directed beam in a specific radiation area 3. According to the embodiment shown in FIG. 17, the converted radiation is emitted perpendicular to a plane in which the μ-LED chip with its semiconductor substrates is located.

(155) The structured layer 2 shown in FIG. 17 is a two-dimensional photonic crystal etched into the LED semiconductor substrate above the active layer of the μ-LED. The individual, here rod-shaped and periodically arranged recesses of structure 4 have been filled with the converter material. The layer thickness of structure 4 is at least 500 nm, so that a band gap is created in the crystalline solid-state material, which causes a directionality of the converted radiation emitted by converter element 1. In this example, the recesses are round and arranged in a hexagonal pattern in the center of which a recess is also arranged. However, the recess itself can also take other shapes, for example hexagonal or square. Round recesses have the advantage that they are easier to produce. The recesses show the same distance and have the same size. This circumstance is also due to the application.

(156) For example, the recesses can be of different sizes or have different spacing. This results in a different periodicity, so that a different optical band gap is formed. In a similar embodiment, the recesses can have a first periodicity in a first direction (i.e. first distance from each other and size) and a second periodicity in another, e.g. orthogonal direction. This result in a different band gap in the two spatial directions and a wavelength-dependent selection can be made. With a suitable setting, a full conversion of the incident light is possible, so that the μ-LED emits converted light substantially parallel to the recesses.

(157) Such a photonic structure can significantly increase directionality and thus efficiency, especially of etendue-limited systems. Due to the provision of a layer 2 with a corresponding structure 4 and suitable converter material directly on the surface of the μ-LED 7, the otherwise additionally provided optical elements can be dispensed and thus a comparatively small radiation source can be realized by exploiting the invention. In addition, a particularly efficient radiation source is made available, since on the one hand, no light is emitted in an unneeded direction that is not perpendicular to the LED chip surface, and on the other hand, all the converted light can be used. Furthermore, modes of the excitation radiation emitted by the μ-LED 7, which are guided in the active zone 9 and have a low extraction efficiency from the μ-LED 7, can be efficiently converted.

(158) In addition, FIG. 18 shows the sectional view of a radiation source 6, which is configured as explained in connection with FIG. 17, but additionally has a filter element 5 applied to the top layer of the radiation source 6 in the form of a filter layer 5, which is opaque to radiation of selected wavelength ranges. The filter layer 5 has the function of a color filter.

(159) Such a technical design is particularly suitable for radiation sources 6, in which a μ-LED 7 and a converter element 1 are combined in such a way that the light emitted by the μ-LED 7 is fully converted. With the aid of a suitably designed filter layer 5, the radiation emitted in the emission range 3 can thus be limited to radiation with a desired wavelength. Such a filter layer 5 also ensures that the excitation radiation emitted by LED 7, which is not converted into converted radiation by converter element 1, is prevented from escaping into emission range 3 by means of filter layer 5 if necessary.

(160) In an alternative embodiment, layer 3 of FIG. 18 assumes an out-coupling function in order to appropriately couple out the light formed by the photonic structure. However, a combination of these two functionalities is also possible. In this context, layer 3 can also be structured, for example roughened, in order to better couple out the light.

(161) FIG. 19 again shows a radiation source 6, which has a μ-LED 7 and a converter element 1 applied to a semiconductor substrate 8 of the μ-LED 7. Converter element 1 comprises a layer 2 with converter material and a structure 4, which is applied to a semiconductor substrate 8 of LED 7. The structured layer 2 is preferably a photonic crystal, a quasi-periodic or deterministically aperiodic photonic structure. The structure 4 of layer 2 is filled with suitable converter material.

(162) In contrast to the embodiment explained in FIG. 17, however, the structured layer 2 is not only arranged in a semiconductor substrate in the upper area of the radiation source 6, but extends into the active zone 9 of the μ-LED 7. Again, a structured layer 2 with a layer thickness greater than 500 nm is provided, thus creating an optical band gap. Also in this case, modes of the excitation radiation emitted by the μ-LED 7, which are guided in the active zone 9 and have a low extraction efficiency from the LED, can be efficiently converted.

(163) In addition, FIG. 20 shows a configuration of a radiation source 6, which is configured as shown in FIG. 19 and additionally has a filter element 5 applied to the top layer of the radiation source 6, which is designed in the form of a filter layer serving as a color filter. Such color filters offer the possibility to limit the emission of the converted radiation into the emission range in case of a full conversion of the excitation radiation emitted by the μ-LED 7 or to selectively suppress the emission of unconverted excitation radiation in case of a not complete conversion.

(164) FIGS. 21A and 21B show a μ-display with a photonic structure for the emission of light that preferably emerges vertically from a light emission surface 21. The device comprises an array 11 having pixels, wherein optically acting nanostructures in the form of a photonic crystal K are formed over the entire emitting surface of the light exit surface 21. The array 11 also comprises an array-like arrangement of light sources, each of which comprises a recombination zone 2, which lies in a recombination plane 1.

(165) The recombination zones 2 are formed in a first layer of optically active semiconductor material 3 of array 11. The zones 2 can comprise quantum dots, one or more quantum wells or even a simple pn junction. In order to obtain more localized recombination regions, it may be intended to limit recombination to predefined areas by current confinement or other structural measures.

(166) In the layer with the semiconductor material 3, the photonic crystal or photonic crystal structures K are structured, namely in the form of a two-dimensional photonic crystal. The photonic crystal K is located between the recombination zones 2 and the light-emitting surface 21. The photonic crystal structures K can be arranged independently of the positioning of individual pixels, whereby in the example shown one pixel corresponds to one or three light sources with a recombination zone 2. Three light sources, therefore, so that any color can be produced by suitable color mixing.

(167) The optically active photonic crystal structures K are filled free-standing in air or, as shown, with a first filling material 7, in particular electrically insulating and optically transparent, in particular SiO.sub.2, with a refractive index which is lower than the refractive index of the semiconductor material 3. The filling material 7 preferably also comprises a low absorption coefficient.

(168) In the array 11, both electrical poles of each light source are electrically connected by means of an optically reflective contact layer 5 for the electrical contacting of the light sources. The contacting layer 5 is located on a side of the optically active semiconductor material 3 facing away from the optically active photonic crystal structures K and is arranged below as shown in FIG. 21B. This type of contacting enables very strongly localised recombination zones 2. For this purpose, the contacting layer 5 comprises at least two electrically insulated areas in order to be able to connect the poles electrically separately.

(169) The photonic crystal K can be structured over the entire emitting surface 21 in such a way that at least approximately only light with a propagation direction perpendicular to the surface 21 can leave the component. If the photonic crystal K is close to the recombination plane 1 and the layer thickness of the photonic crystal K is large in comparison to the distance to the recombination zone 2, the optical density of states in the area of light generation is additionally changed.

(170) This makes it possible to generate a complete bandgap for optical modes with propagation direction parallel and at a small angle to the surface of the, in particular, planar, i.e. in particular flat and/or smooth, pixel-containing array 11. The emission of light with propagation direction parallel to the emitting surface is then completely suppressed.

(171) In particular, light can only be generated in a limited emission cone, which is defined by the photonic crystal K. In this case, directionality is already ensured at the level of light generation, which effectively increases efficiency compared to an angle-selective optical element, since such an element only influences light extraction.

(172) The alignment of the photonic crystal K is independent of the positioning of the individual pixels, especially in such a way that an alignment of the pixel structure to the photonic structure K is not necessary and processing of an entire wafer surface is possible. It is a reasonable embodiment if the device is homogeneous in its optical properties over the entire surface of the array 11 or varies only slightly so as not to disturb the optical environment of the photonic crystal K.

(173) FIGS. 22A and 22B show a second proposed optoelectronic device in a plan view and in cross-section respectively. In the pixelated array 11, the photonic crystal K is arranged in a second layer of a material 9, in particular Nb.sub.2O.sub.5, above a first layer of the optically active semiconductor material 3, as an alternative to the embodiment shown in FIGS. 21A and 21B. The material 9 thereby has a large optical refractive index and it is arranged on the flat and/or smooth surface of the semiconductor material 3. Preferably, the material 9 also comprises a low absorption and is therefore very transparent. The contacting is similar to that shown in FIGS. 21A and 21B and allows very localized recombination zones 2.

(174) Alternatively, some embodiments may provide that the material is also electrically conductive. This is especially useful if the different pixels are designed with vertical μ-LED packages and are to be connected to a common contact.

(175) As shown in FIGS. 21A and 21B, columns are formed from the material 9 and the photonic crystal K is in turn formed as a free-standing two-dimensional photonic crystal. The space between the columns is filled with a different material with a lower refractive index than in FIGS. 21A and 21B. A possible filling material is for example SiO.sub.2.

(176) FIGS. 23A and 23B show a third proposed optoelectronic device in a top view and in a cross-section, respectively. The device shown comprises as light sources an array of vertical μ-LEDs 13 and a two-dimensional photonic crystal structure K arranged in an overlying layer, which extends over the entire emitting surface 21 and is formed from a material 9 with a high refractive index. The free space of the structure K is in turn filled with filler material 7 with a lower optical refractive index.

(177) The vertical light-emitting diodes 13 have an upper and a lower electrical contact along a vertically oriented longitudinal axis, which is perpendicular to the light-emitting surface 21. The light-emitting diodes thus comprise an electrical contact on the front side and an electrical contact on their rear side. The rear side is the side of the μ-LEDs 13 facing away from the light emission surface 21, while the front side faces the light emission surface 21.

(178) The device comprises an electrically conductive and the generated light reflecting contacting layer 5 for the electrical contacting of the contacts on the back of the LEDs 13 The contacting layer 5 is designed in such a way that the individual μ-LEDs can be controlled separately. For the electrical contacting of the contacts on the front of the LEDs 13, a third layer is provided, which comprises an electrically conductive and optically transparent material 17, for example ITO. An electrical connection to the corresponding pole of a power source can be established via a bonding wire 19.

(179) In and along the recombination level 1, a further, in particular electrically insulating, filling material 15 can be arranged between the third layer and the optically reflective contacting layer 5. This electrically separates the μ-LED from each other. In addition to this structure shown here, other pixelated components disclosed in this application may also be provided with the structure K. These include, for example, the disclosed antenna structures, the μ-LED in bar form or the μ-LED modules. Likewise, in all the embodiments shown here, reflective structures may be provided in layer 5 which deflect the light in the direction of the exit surface. These include the structures surrounding the actual μ-LED, which are disclosed in this application.

(180) FIGS. 24A and 24B show a fourth version of a μ-display in a top view and cross-section. The μ-display or module device comprises an array of horizontal μ-LEDs 13 with respective recombination zones 2 and an optically effective two-dimensional photonic crystal structure K below the total emitting surface 21. The photonic crystal structure K is located in a layer of a material 9 with a high refractive index, for example Nb.sub.2O.sub.5. Free spaces are in turn filled with filling material 7, for example silicon dioxide, with a lower optical refractive index.

(181) In the case of the horizontal LEDs 13, both electrical contacts are located on the rear of the LEDs 13. Both poles of the LEDs 13 are electrically connected by means of electrically separated areas of the optically reflective contact layer 5. In the area of the recombination level 1, a filling material 15, in particular an electrically insulating one is arranged between the material layer 9 and the contacting layer 5.

(182) The efficiency with respect to light generation is relatively high in the embodiments according to FIGS. 21A to 24B, since in these embodiments directionality or directionality of the light is already achieved during light generation, especially if a higher photonic state density can be achieved in the area of the recombination zones 2 for the emission of light in the direction perpendicular to the light exit surface by means of the band structure of the photonic crystal K. A further advantage is that the structuring of the photonic crystal K can be carried out homogeneously over an entire wafer. A certain positioning or orientation of the photonic crystal to the individual pixels or micro light emitting diodes is not necessary. This will significantly reduce manufacturing complexity, especially compared to alternative approaches where structures are placed individually over each pixel.

(183) FIGS. 25A and 25B show a fifth proposed optoelectronic device in a top view and cross-section. The device comprises a pixelated array 11 and optically acting columnar or pillar structures P, in particular with pillars or columns structured over the entire emitting surface 21. The array 11 is smooth and flat on its surface.

(184) The pixelized array 11 in this configuration comprises a large number of subpixels, each with a light source that includes a respective recombination zone 2. The recombination zones 2 of the pixels are located in a recombination plane 1 and they are arranged in a first layer with optically active semiconductor material 3.

(185) Above this first layer the pillar structures P are formed. One pillar P is assigned to a light source, so that each Pillar P is located directly above the recombination zone 2 of the assigned light source. A longitudinal axis L of each pillar P runs in particular through the center M of the recombination zone 2 of the assigned light source 2. The pillars P consist of a material 9 with a high refractive index, for example Nb.sub.2O.sub.5. A filler material 7 with a lower refractive index, such as silicon dioxide, can be arranged in the spaces between the pillars P.

(186) The pillars P can be arranged above the layer with the light sources, in particular by additionally applying the pillars P above array 11. Alternatively, the pillars can be etched into the semiconductor material 3. For this purpose, the semiconductor material layer must be appropriately high. Since the semiconductor material normally comprises a high refractive index, material can be etched away in such a way that the pillars 9 remain standing. The areas freed up by etching can be filled with material of low refractive index.

(187) The pillars P act like waveguides which guide light upwards in the direction of the longitudinal axis L, so that the pillars P can cause an improved emission of light in a direction perpendicular to the light emission surface 21. In addition to the design shown here, the periodicity of the pillar structures can also be different, for example, the pillars can be located alternately above one μ-LED and between two adjacent μ-LEDs. This results in a double density of columns. The periodicity determines the optical band structure and thus the properties with regard to light extraction.

(188) In the array 11, both electrical poles of a light source are electrically connected to the recombination zones 2 by means of a reflective contact layer 5. The contacting layer 5 is formed on a side of the semiconductor material 3 that is turned away from the optically active pillar structures P. The contacting layer 5 can have two separate areas in order to be able to contact electrically the two poles separately. This type of contacting allows very localized recombination zones 2.

(189) FIGS. 26A and 26B show a sixth optoelectronic device in a top view and cross-section. The device comprises an array of vertical μ-LEDs 13. Optically active pillar structures P, in particular with pillars or columns, are arranged above the array of μ-LEDs 13. The longitudinal axis L of the pillars P runs at least essentially through the centers of the recombination zones 2 of the μ-LEDs 13.

(190) Pillar structures P may be free-standing in air or filled with a first filling material 7, in particular electrically insulating and optically transparent, above the light-emitting diodes. The filling material 7 may comprises a lower refractive index than the refractive index of the material 9 of the pillars P and/or the semiconductor material 3 of the μ-LEDs 3. The reverse form is also possible, i.e. material 7 has a higher refractive index than the material of the pillars, but this changes the light guidance of the pillars.

(191) As already mentioned, the μ-LEDs are vertical micro-light emitting diodes 13, which comprise one, especially positive, electrical pole on their back side facing the reflective contact layer 5 and another electrical pole on the front side facing the pillars P.

(192) The pole at the front of the light sources is electrically connected to an appropriate power supply (not shown) by means of a layer of an electrically conductive and optically transparent material 17, in particular ITO, and by means of a contact wire 19. The layer of material 17 is placed between the light sources and the pillars 17, as shown.

(193) A second filling material 15 can be arranged in free spaces in the layer of μ-LEDs 13 and thus between the layer with the material 17 and the contacting layer 5.

(194) Pillar structures P can also be described as micropillar structures or micropillars, since their dimensions, in particular their cross-section, can at least approximately correspond to the dimensions of the micro light-emitting diodes 13 or the pixels of an array 11.

(195) FIGS. 27A and 27B show a seventh optoelectronic device in a top view and cross-section. In contrast to the variant in FIGS. 26A and 26B, the device in FIGS. 27A and 27B comprises an array of horizontal micro-light-emitting diodes 13, the electrical poles of which are located at the rear of the microlight-emitting diodes 13. For electrical contacting, therefore, both electrical poles of a light source can be electrically connected via two electrically separated areas of the reflective contacting layer 5. The intermediate layer with the material 17 as in the variant with vertical micro light emitting diodes described above is therefore not required.

(196) In comparison to the arrangements with the photonic crystal structures K according to FIGS. 21A to 24B, the variants with the pillars P can be manufactured more easily with standard technologies, since the structure sizes with diameters of up to 1 μm or more are significantly larger. The process requirements are therefore lower and high-resolution lithography can be sufficient for the manufacture of the pillars.

(197) Pillar structures, in particular pillars or columns, made of the optically active semiconductor material 3 or a material 9 with a refractive index as high as possible can be precisely structured via individual pixels of the array 11 or via vertical micro-light emitting diodes 13 (FIGS. 26A and 26B) or via horizontal micro-light emitting diodes 13 (FIGS. 27A and 27B). The individual pixels or micro-lighting diodes 13 may be smaller than 1 μm in diameter and the pillars may have an aspect ratio height:diameter of at least 3:1. Pillars are preferably etched directly into the semiconductor material 3, as is possible in FIGS. 25A and 25B and in FIGS. 27A and 27B, because there is no third layer 17 as shown in FIG. 26B, or they are made of another material 9 with a high refractive index and preferably low absorption, which is applied to the surface of the array 11. A possible material with a high refractive index is for example Nb.sub.2O.sub.5. Pillar structures can be free-standing or filled with a material 7 of low refractive index. A possible filling material with low refractive index is for example SiO.sub.2. Due to the higher refractive index of the pillars compared to the surrounding material, the emission parallel to the longitudinal axis of the pillars is enhanced compared to other spatial directions. Due to a waveguide effect, light along the longitudinal axis of the pillars is additionally coupled out more efficiently than light with other propagation directions. This improves the directionality of the emitted light.

(198) FIGS. 28A and 28B show an eighth proposed optoelectronic device in a top view and cross-section. The device comprises an array of μ-LED 13, each of which is configured with pillar P and thus in column form.

(199) The length of the pillars P can correspond to half a wavelength of the emitted light in the semiconductor material 3 and the recombination zone 2 can preferably be located in the center M of a respective pillar and thus in a local maximum of the photonic state density. The aspect ratio height:diameter of the pillars P can be at least 3:1.

(200) In the arrangement shown, the pillars P can be about 100 nm high and have a diameter of only about 30 nm. This requires a very finely resolved structuring technique and can be realized with current production technologies at wafer level with a lot of effort.

(201) Alternatively, the dimensions can be upscaled to simplify manufacture, with the directionality of the emitted light decreasing as the size of the pillar structure increases. The length of the pillars P is preferably a multiple of half the wavelength of the emitted light in the semiconductor material, and the respective recombination zone 2 can be at a maximum of the photonic state density.

(202) Due to the pillar structuring of the μ-LED 13, the emission parallel to the longitudinal axis of the pillars P is effectively amplified by the higher photonic state density. Due to a waveguide effect, light with a direction of propagation along the longitudinal axis of the pillars P is additionally coupled out more efficiently than light with other directions of propagation. The space between the pillars P is filled with a material 7, which preferably comprises a very low absorption coefficient and a lower refractive index than the semiconductor material 3. A possible filling material with a low refractive index is for example SiO.sub.2.

(203) In this arrangement of micro-lighting diodes 13, in particular vertical micro-lighting diodes 13 formed as pillars P or columns, a first pole, in particular a positive pole is electrically connected by means of a reflective contacting layer 5 for contacting recombination zones 2 arranged in a recombination plane 1. The contacting layer 5 is formed at the lower, first longitudinal ends of the μ-LEDs 13.

(204) The respective other, in particular negative, second pole is electrically connected to a third layer of a conductive transparent material 17, in particular ITO, and connected by means of a bonding wire 19 for example to the corresponding pole of a power supply.

(205) According to this arrangement, the third layer is formed in and along the recombination plane 1 in the longitudinal centers of the μ-LEDs 13, which are shaped as pillars P or columns.

(206) FIGS. 29A and 29B show a ninth optoelectronic device in a top view and cross-section. In contrast to the variant in FIGS. 28A and 28B, the device in FIGS. 29A and 29B comprises vertical μ-LEDs in the form of pillars P.

(207) The electrical contact at the bottom, in particular the p-contact, is established via the bottom of the pillars P and in particular by contacting the contact layer 5. The electrical contact at the top, especially the n-contact, is on the upper side of the pillars P. The contact is established via an upper layer of optically transparent and electrically conductive material 17. The upper layer extends over the pillars P and the first filling material 7, with which the free spaces between the pillars P are filled. A possible material 17 for the upper layer is ITO (indium tin oxide), for example. A connection to a power supply can be established via the bonding wire 19.

(208) The electrical contacting of the light-emitting diodes in the pillars P enables very strongly localized recombination zones 2, whereby the upper contact, in particular an n-contact, can be formed at the level of the recombination zones 2 or on the upper side of the pillars P. Each pillar P generates an individual pixel.

(209) The emission of light parallel to the longitudinal axis of μ-LEDs 13 in the form of pillars as shown in FIGS. 28A to 29B is increased. This improves the directionality of the emitted light compared to conventional micro-light emitting diodes with small aspect ratio. Compared to an arrangement according to FIGS. 25A to 27B, the process of light generation can be influenced much more strongly by an arrangement according to FIGS. 28A to 29B, thus achieving high directionality and efficiency.

(210) FIG. 30 shows a cross-sectional view of another optoelectronic device in which a two-dimensional photonic crystal K is arranged over a layer with an array of light sources with recombination zones 2. The photonic crystal K is thereby arranged so close to the recombination zones 2 that the photonic crystal K changes an optical state density present in the region of the recombination zones 2, in particular in such a way that a band gap is generated for at least one optical mode with a direction of propagation parallel and/or at a small angle to the light exit surface 21 and/or the state density is increased for at least one optical mode with a direction of propagation perpendicular to the light exit surface 21.

(211) This can be achieved in particular by the fact that the height H of the photonic crystal K is at least 300 to 500 nm, preferably up to 1 μm. The height H of the photonic crystal may depend on the high refractive index material of the photonic crystal.

(212) Furthermore, a distance A between the center M of the recombination zones 2 and the bottom of the photonic crystal K is at most 1 μm and preferably a few 10 to a few hundred nm.

(213) All the described configurations with a photonic crystal K are two-dimensional photonic crystals, which exhibit a periodic variation of the optical refractive index in two spatial directions perpendicular to each other and parallel to the light-emitting surface. Furthermore, it is preferably a pillar structure comprising an array of pillars P or columns, the longitudinal axis L of the pillars P being perpendicular to the light-emitting surface 21.

(214) FIG. 31 shows an optoelectronic device 1 with a photonic structure for emitting polarized light. The component 1 comprises an emitter unit 2, which has a light-emitting surface 3 and on which a polarizing element 4 in the form of a polarizing layer with a three-dimensional photonic structure is applied. With the help of photonic structures for polarization of electromagnetic radiation, it is especially possible to take special pictures and show them on suitable displays. According to the embodiment shown in FIG. 31, emitter unit 2 is a μ-LED 5, which emits light in the visible or possibly also in the ultraviolet wavelength range. The light emitted by the μ-LED 5 is guided into the three-dimensional photonic structure and here it is polarized in a certain direction of oscillation depending on the design and dimensioning of the structure. Depending on the design of the three-dimensional photonic structure, either circular or linear polarization can be used. The light emitted in this way therefore comprises a specific polarization, which is predetermined by the photonic structure.

(215) If the three-dimensional photonic structure of polarization element 4 has spiral structure elements 6 as shown in FIG. 32, a circular polarization occurs. If, on the other hand, the structural elements of the three-dimensional photonic structure are rod-shaped, in particular in the form of so-called nanorods, this causes a linear polarization of the radiation guided through the three-dimensional photonic structure.

(216) The optoelectronic device 1 shown in FIG. 31 is manufactured by the two-photon lithography process, the glancing angle deposition process, laser interference lithography or by holographic patterning. It should be noted that the spiral-shaped features 6 shown in FIG. 32 have been fabricated using the glancing angle deposition technique.

(217) The illustration in FIG. 31 shows only a single optoelectronic component. However, a large number of these components can be manufactured together and provided as an array or μ-LED module, as shown in FIGS. 187, 189 to 192, for example. In this way, different components can be interconnected, but with complementary properties. Thus, components 1 or also arrays or μ-LED modules are combined for imaging, which have different polarization and/or transmission properties.

(218) The radiation generated by several illumination units, each with complementary properties, polarized in different directions of oscillation, is projected onto a display or screen by means of common optics disclosed therein.

(219) With the three-dimensional photonic structure arranged on the surface or light-emitting surface 3 of an LED chip as shown in FIG. 31, which forms a polarization element 4, it is possible to generate light with fundamentally different properties, in particular with defined polarization, than is possible with the currently known LEDs. The advantage is that due to the provision of a three-dimensional photonic structure on the chip surface, no additional optical components, such as a classical polarization filter, are required. This is particularly useful in the area of μ-LEDs, since such photonic structures are easier to produce by means of lithographic processes than by positioning and attaching separate polarization filters. The illumination unit can therefore be made comparatively small. Due to the structuring directly on the semiconductor chip of the LED 5, such an optoelectronic component 1 is also more energy-efficient than the known components in which the polarization is subsequently selected. Any photon that does not pass through the three-dimensional photonic structure due to its properties remains in the μ-LED chip and can be re-emitted by a reabsorption process.

(220) FIG. 33 shows an illumination unit or an optoelectronic component 1 with an emitter unit 2, which comprises a light-emitting surface 3 on which a polarizing element 4 with a three-dimensional photonic structure that has wavelength-selective properties is applied. The photonic structure in this case is a three-dimensional photonic crystal. Alternatively, several two-dimensional photonic crystals can be arranged in layers one above the other.

(221) The three-dimensional photonic structure is designed to have wavelength-specific transmittance and polarization properties. This means that the transmittance and polarization properties of the three-dimensional photonic structure vary depending on the wavelength of the incident radiation.

(222) Component 1 shown in FIG. 33 has an emitter unit, which in turn has a μ-LED 5. A converter element 7 with a layer of converter material is also provided. The converter material emits a converted radiation 9 due to excitation by the excitation radiation 8 emitted by the LED 5, which comprises a different wavelength than the excitation radiation 8.

(223) If both unconverted excitation radiation 8 and converted radiation 9 impinge on the three-dimensional photonic structure, these radiations are influenced in different ways depending on their wavelength with respect to transmission and polarization. As shown in FIG. 33, the converted radiation 9 is coupled out perpendicular to the surface of the LED chip, while the excitation radiation 8 is deflected laterally.

(224) Such lighting units can be used in a preferred way in components in which radiation with different wavelengths is generated, whereby different functions can be implemented with a combination of μ-LEDs and converter elements. Depending on the design of the three-dimensional photonic structure and the wavelength of the excitation radiation 8 emitted by each LED, it is possible to achieve complete suppression of the excitation radiation 8, while the converted radiation 9 passes through the three-dimensional photonic structure. It is also conceivable that the excitation radiation 8 is deflected while the converted radiation 9 is coupled out perpendicular to the chip surface, as shown in FIG. 33. Of course, the mechanism can also be reversed. Furthermore, it is also conceivable to polarize the converted radiation 9 in a special way, while the excitation radiation 8 emerges unchanged via the chip surface. Here too, the mechanism can be reversed.

(225) The variant of an illumination unit shown in FIG. 34 comprises an emitter unit, here again in the form of a μ-LED 15, and a three-dimensional photonic structure 11, for example a spiral-shaped photonic structure 11. Converter material 13 is filled into structure 11.

(226) The optoelectronic component 11 shown in FIG. 35 comprises at least one μ-LED 13, which is designed to emit electromagnetic radiation 19, such as visible or infrared light of one wavelength, via a light emission surface 15. A photonic structure 17 is provided for beam-shaping of the electromagnetic radiation before it exits via the light exit surface 15. The photonic structure 17 shapes the electromagnetic radiation 19 in such a way that the electromagnetic radiation 19 comprises a defined characteristic 23 (Far-field characteristics).

(227) In particular, the photonic structure 17 of the illumination unit 11 of FIG. 35 is a one-dimensional photonic crystal 25, which in the variant shown extends to the light-emitting surface 15. The front side of the photonic crystal 25 thus forms the light-emitting surface 15. The one-dimensional photonic crystal 25 exhibits a periodic variation of the optical refractive index along a first direction R1.

(228) The crystal 25 or the periodic variation are adjusted to beam the electromagnetic radiation emitted by a light source (not shown) of the μ-LED. Especially a light propagation along the first direction R1 is blocked. As a result, the emitted radiation 19 in far-field 21 comprises only a slight extension along the first direction R1. A characteristic feature of electromagnetic radiation 19 in far-field 21 is therefore that it forms a narrow strip 27. The electromagnetic radiation 19 is therefore collimated with respect to the first direction 19.

(229) The light source is a μ-LED. This is typically a Lambertian radiator. By using the photonic structure 17 and the resulting beam-shaping a directed, collimated electromagnetic radiation 19 can be generated.

(230) As FIG. 35 schematically shows, the emitted electromagnetic radiation 19 leaves the μ-LED 13 in the form of a light cone that substantially fans out along a second direction R2. The central axis of the light cone extends along a main radiation direction H, which is perpendicular to the light exit surface 15. Not shown is a collimating, optional optical system arranged downstream of the light exit surface 15 when viewed in the main radiation direction H. By means of the optics, the electromagnetic radiation 19 can be collimated in the second spatial direction R2, which is orthogonal to the first spatial direction R1. The electromagnetic radiation 19 can thus be collimated in the far field 21 with respect to the two directions R1, R2. A luminous point is created. This luminous point is particularly favourable for displays as mentioned at the beginning, because the beam is strongly collimated in both directions in space.

(231) An optoelectronic component 11 as shown in FIG. 35 is particularly well suited for use in an optical scanner. Here, the illumination device 11 can be used especially for line scan applications due to the stripe-like light image in far field 21.

(232) In the optoelectronic device 11 shown in FIG. 36, a one-dimensional photonic crystal 25 is formed on the upper side of an emitter unit 13a. The front face of the crystal 25 forms the light-emitting surface 15 for electromagnetic radiation generated by an unrepresented optoelectronic light source, for example an LED or μ-LED, which is emitted through the photonic crystal 25 via the light-emitting surface 25.

(233) In contrast to the variant shown in FIG. 35, the main direction of radiation H of the electromagnetic radiation 19 of the lighting unit of FIG. 36 is at an angle α to the normal N of the light-emitting surface 15. The angle α is not equal to zero degrees. For example, the angle α can be in the range between 30 and 60 degrees. This is achieved by the fact that the one-dimensional photonic crystal 25 comprises a periodically repeating sequence of two materials 31, 33 with different optical refractive indices extending in a first direction R1. The materials 31, 33 have a parallelogram-like cross-section and abutting interfaces of the materials 31, 33 do not run orthogonally but are inclined to the light-emitting surface 15, as shown schematically in FIG. 36.

(234) Such a structure can be formed, for example, by etching trenches 29 running parallel to each other at an angle to the light emission surface 15 into the substrate 31 having the light emission surface 15. The trenches 29 can be filled with a material 33, which comprises a different optical refractive index than the substrate material 33, which has been etched away. The angle α may depend on the inclination of the trenches 29 to the light-emitting surface 15. The width of the trenches 29 and the width of any substrate material 31 remaining between two trenches 29 influences the wavelengths at which the photonic crystal 25 can be affected. Typically, the width of the trenches 29 and the width of the substrate material 33 remaining between two trenches, and thus also the periodicity of the photonic crystal structure 25, are adapted to the wavelength of the electromagnetic radiation provided by the light source or a converter material located between the light source and the photonic crystal.

(235) Using the one-dimensional photonic crystal 25, component 11 of FIG. 36 can in turn generate a light strip 27 in the far field 21, as described in relation to FIG. 35. In contrast to the variant in FIG. 35, the main radiation direction H in the variant in FIG. 36 is tilted by the angle α relative to the normal N. By means of a downstream collimating optic, the strip 27 can be brought into a point-like or circular structure in the far field 21.

(236) The variant shown in FIG. 37 comprises a linear or array arrangement of several optoelectronic components 11 of FIG. 36, the light beams 19 emitted by the individual components 11 having the same main radiation direction H. The light beams 19 can also be collimated by an additional collimating optic 35, in particular a lens, in a second direction, which, in the representation of FIG. 37, is perpendicular to the image plane. This results in a point or circular image of the emitted radiation 19 in the far field behind the lens 35.

(237) The use of a photonic crystal in an illumination device 11 as shown in FIGS. 36 and 37 results in an effectively higher resolution for a line-array arrangement of illumination devices 11 as shown in FIG. 37. μ-display or modules having such features allow very directional radiation, so that the pixel sharpness is very high. This means that the contrast remains very high even with adjacent pixels and optical crosstalk is reduced. In addition, smaller beam cross-sections can be realized, especially in the far field, downstream of optics 35. Since collimation in the first direction R1 (cf. FIG. 36) is already achieved by the photonic crystals 25 integrated in the illumination devices 11, optics 35 and possibly further, subsequent optics can be made more compact.

(238) In the variant of FIG. 38, the optoelectronic component or lighting unit 11 comprises a photonic structure 17, which is a two-dimensional photonic crystal 37, whose front side forms the light-emitting surface 15. Viewed from the light exit surface 15, at least one optoelectronic light source, optionally with converter material, is arranged behind the photonic crystal 37. The photonic crystal 37 is designed to shape the electromagnetic radiation 19 emitted via the light exit surface in such a way that it produces a defined, discrete pattern 39 in the far field 21. In the example shown, the pattern 39 consists of several distributed light spots 41, although other patterns are also possible. In particular, the photonic crystal can be formed to produce only one central pixel. This structure is particularly useful for displays.

(239) The illumination device 11 in FIG. 38 is suitable for use in a surface topography detection system 43, for example, as shown in the block diagram in FIG. 39. In addition to the illumination device 11, the system 43 includes a detection unit 45 with a camera 47, which is designed to detect the pattern 39 when it illuminates an object (not shown).

(240) Furthermore, an analysis device 49 is provided which is designed to detect a distortion of the pattern 39 in relation to a given reference pattern. The reference pattern can, for example, be determined from the detection of pattern 39 when it is projected onto a flat surface. The analyser 49 is also adapted to determine a shape and/or a structure of the object illuminated by the pattern 39 in the far field 39 depending on the detected distortion of the pattern 39. By means of the system 43, face recognition can thus be realized, for example. In the case of applications in the Augmented Reality area, some pixels can be formed with a crystal such as the one shown in FIG. 38 in order to detect the reflection on the eye a direction of vision or its change. This allows a user to follow and superimpose information into the field of view for sharp vision.

(241) In the variant shown in FIG. 39, downstream optics for pattern generation can be dispensed with, since pattern 39 can already be generated using photonic crystal 37. The lighting device 11 as shown in FIG. 38 and the associated system 43 as shown in FIG. 39 can therefore be implemented in a particularly compact form.

(242) In the following, various devices and arrangements as well as methods for manufacturing, processing and operating as items are again listed as an example. The following items present different aspects and implementations of the proposed principles and concepts, which can be combined in various ways. Such combinations are not limited to those listed below:

(243) 565. μ-LED, comprising: a layer stack of a p-doped layer; an n-doped layer; an active region located between the p-doped and n-doped layer;
wherein the layer stack rises above a major surface and the active region is located above a center of the layer stack as viewed from the major surface, wherein the layer stack has a reducing diameter from the major surface;
a reflective layer over a surface of the layer stack.

(244) 566. μ-LED according to item 565,

(245) in which the stack of layers comprise the shape of a hemisphere or a paraboloid or an ellipsoid.

(246) 567. μ-LED according to any of the preceding items, in which areas of the active layer adjacent to the reflective layer comprise an increased bandgap.

(247) 568. μ-LED according to any of the preceding items, in which areas of the active layer adjacent to the reflective layer exhibit quantum well intermixing.

(248) 569. μ-LED according to any of the preceding items, in which the reflective layer comprises a dielectric between the active region and the layer of the layer stack adjacent to the surface region.

(249) 570. μ-LED arrangement for generating a pixel of a display, comprising a flat carrier substrate; and at least one μ-LED, which is arranged on a mounting side of the carrier substrate
wherein the μ-LED is adapted to emit light transverse to a carrier substrate plane in a direction away from the carrier substrate; a flat reflector element;
wherein the reflector element is spatially arranged on the assembly side relative to the at least one μ-LED and is configured to reflect light emitted by the at least one μ-LED in the direction of the carrier substrate;
wherein the carrier substrate is at least partially transparent so that light reflected from the reflector element propagates through the carrier substrate and emerges at a display side of the carrier substrate opposite the mounting side.

(250) 571. μ-LED arrangement according to item 570, wherein a diffuser layer is provided and/or a reflector material has diffuser particles for scattering the light reflected by the at least one μ-LED on the side of the reflector element directed towards the at least one μ-LED.

(251) 572. μ-LED arrangement according to item 571, wherein the diffuser layer and/or the diffuser particles comprise Al.sub.2O.sub.2 and/or TiO.sub.2.

(252) 573. μ-LED arrangement according to any of the preceding items, wherein the reflector element surrounds the at least one μ-LED in a circular, polygonal or parabolic shape.

(253) 574. μ-LED arrangement according to any of the preceding items, wherein the reflector element forms an electrical contact of the at least one μ-LED.

(254) 575. μ-LED arrangement according to any of the preceding items, wherein the reflector element is configured and shaped such that at least 90% of the light emitted by the at least one μ-LED is incident on the mounting side of the carrier substrate at an angle between 45 and 90 degrees relative to the carrier substrate plane.

(255) 576. μ-LED arrangement according to any of the preceding items, in which the at least one μ-LED comprises three μ-LEDs surrounded by the reflector element

(256) 577. μ-LED arrangement according to item 576, in which the at least three μ-LEDs have a contact area on the side facing the reflector element, which is covered with a transparent cover layer for common electrical contact.

(257) 578. μ-LED array according to any of the preceding items, wherein the supporting substrate comprises polyamide, a transparent plastic, resin or glass.

(258) 579. μ-LED arrangement according to any of the preceding items, wherein the reflector element is formed as a reflective layer of the at least one μ-LED.

(259) 580. μ-LED arrangement according to any of the preceding items, wherein a passivation layer is additionally provided for attenuating or eliminating reflections of the light at mesa edges of the at least one μ-LED.

(260) 581. μ-LED arrangement according to any of the preceding items, wherein a light absorbing coating is provided on the assembly side and/or display side of the carrier substrate outside the reflector element.

(261) 582. μ-LED arrangement according to any of the preceding items, wherein the display side of the supporting substrate has an uneven and/or roughened structure.

(262) 583. μ-LED arrangement according to any of the preceding items, wherein a color filter element is arranged on the display side of the carrier substrate opposite the reflector element; wherein the color filter element allows a primary color spectrum of the at least one μ-LED to pass and attenuates deviating color spectra.

(263) 584a. μ-LED arrangement according to any of the preceding items, in which a light-shaping structure, in particular a photonic structure with features after one of the following objects is incorporated in the carrier substrate, which first and second regions with different refractive indexes are incorporated.

(264) 584b. μ-LED arrangement according to any of the preceding items, in which a light-shaping and/or light-converting structure having first and second areas is arranged on the display side of the carrier substrate.

(265) 585. μ-LED arrangement according to item 583 or 584, where first areas comprise a converter material.

(266) 586. μ-LED arrangement according to any of the preceding items, comprising a converter material surrounding the at least one μ-LED and filling the space between μ-LED and reflector material.

(267) 587. μ-LED arrangement according to any of the preceding items, comprising a converter material on the display side of the supporting substrate.

(268) 588. Optical display comprising a plurality of pixel elements each according to any of the preceding items.

(269) 589. A method for producing an optical pixel element, comprising the steps of fixing of at least one μ-LED on an assembly side of a flat carrier substrate; creating a reflector element;
wherein the reflector element is formed as a light-reflecting layer on the at least one μ-LED so that light emitted from the at least one μ-LED is reflected towards the carrier substrate.

(270) 590. Photonic structure on an optoelectronic device, in particular a μ-LED, comprising

(271) a set of layers including an active zone for generating electromagnetic radiation forming the optoelectronic device, and

(272) at least one layer on a main radiation surface having a photonic crystal structure.

(273) 591. Photonic structure on an optoelectronic device according to item 590, the layers of the set of layers and the at least one layer having the photonic crystal structure are arranged one upon another along a growth direction of the layers, and wherein the photonic crystal structure comprise a periodicity in a plane perpendicular to the growth direction.

(274) 592. Photonic structure on an optoelectronic device according to item 590, in which the photonic crystal structure has first and second regions of different refractive index.

(275) 593. Photonic structure on an optoelectronic device according to any of the preceding items, wherein the photonic structure has a first periodicity in a first direction and a second periodicity in a second direction.

(276) 594. Photonic structure on an optoelectronic device as defined in item 593, in which the first and second periodicity are the same.

(277) 595. Photonic structure on an optoelectronic device according to any of the preceding items, in which the photonic crystal structure extends at least partially into one of the layers of the set of layers.

(278) 596. Photonic structure on an optoelectronic device according to any of the preceding items, the periodicity corresponding to about half a specific wavelength, the wavelength corresponding to the wavelength of electromagnetic radiation to be diffracted by the photonic crystal structure.

(279) 597. Photonic structure on an optoelectronic device according to any of the preceding items, wherein the layer having the photonic crystal structure is a dielectric layer containing or consisting of, for example, silicon dioxide, SiO.sub.2, and/or wherein the space within the photonic crystal structure is filled with or consists of a second material having a refractive index different from the refractive index of a first material forming the photonic crystal structure.

(280) 598. Photonic structure on an optoelectronic device according to any of the preceding items, wherein a lower surface of the layer having the photonic crystal structure is disposed on an upper surface of the set of layers.

(281) 599. Photonic structure on an optoelectronic device according to item 598, wherein a portion of at least one layer of the set of layers protrudes into the layer with the photonic crystal structure.

(282) 600. Photonic structure on an optoelectronic device according to item 597 or 599, wherein the upper surface of the set of layers is provided with a surface roughening, for example, a wigwam surface roughening.

(283) 601. Photonic structure on an optoelectronic device after any of the foregoing, wherein the photonic crystal structure is located at a distance from the upper surface of the set of layers.

(284) 602. Photonic structure on an optoelectronic device according to any of the preceding items, further comprising a mirror layer disposed on the layer having the photonic crystal structure.

(285) 603. Photonic structure on an optoelectronic device according to any of the preceding items, further comprising a metal mirror layer, with the set of semiconductor layers disposed between the metal mirror layer and the layer containing the photonic crystal structure.

(286) 604. Photonic structure on an optoelectronic device according to any of the preceding items, wherein the optoelectronic device is a μ-LED.

(287) 605. Optoelectronic device comprising:

(288) at least one optoelectronic light emitting device, for example a μ-LED, wherein said optoelectronic light emitting device is configured to emit light through at least one light emitting surface of said optoelectronic light emitting device,

(289) at least one photonic crystal structure, said photonic crystal structure being disposed between the light-emitting surface of said optoelectronic light-emitting device and a light-emitting surface of said optoelectronic device.

(290) 606. Method for producing an optoelectronic device, in particular according to any of the preceding items, comprising method: growing of a set of layers including an active zone for the generation of electromagnetic radiation, growing at least one layer having a photonic crystal structure on the upper side of the set of layers,
optionally providing a mirror layer over the layer with the photonic crystal structure,
optionally providing a mirror layer under the set of layers with the active zone,
optionally executing an etching process, such as a Mesa dry etching process.

(291) 607. Method for producing a μ-LED comprising a creating of an out-coupling structure in a surface region of a semiconductor body providing the active layer of the μ-LED by means of

(292) structuring of the surface area; and

(293) planarizing the structured surface area to obtain a planarized surface of the surface area.

(294) 608. Method according to item 607, wherein the step of structuring the surface area comprises at least one of the following steps: generating of a random topology at the surface area; roughening the surface of the surface region of the semiconductor body comprising a first material; applying, in particular layer-by-layer applying of a transparent second material having a high refractive index, in particular greater than 2, to the surface region and roughening of the second material; creating an ordered topology on the surface area;
applying, in particular layer-by-layer applying of a transparent second material having a high refractive index, in particular greater than 2, to the surface region and structuring of periodic photonic structures or non-periodic photonic structures, in particular quasi-periodic or deterministic aperiodic photonic structures, into the second material.

(295) 609. Method according to item 608,

(296) characterised in that

(297) the transparent second material with the high refractive index Nb.sub.2O.sub.5.

(298) 610. Method according to any of the preceding items, in which the step of planarizing comprises:

(299) applying, in particular layer by layer, a transparent third material of low refractive index, in particular less than 1.5, to the structured surface region; and

(300) optionally thinning the applied transparent third material of low refractive index until the surface of the structured surface region terminates flat and/or smooth with highest elevations in the first material of the semiconductor body or in the second material of high refractive index.

(301) 611. Method according to item 610, in which

(302) the transparent third material having a low refractive index SiO.sub.2, and is applied in particular by means of TEOS (tetraethylorthosilicate).

(303) 612. μ-LED comprising an out-coupling structure in a surface region of a semiconductor body providing the μ-LED

(304) in which the surface area is planarized so that a smooth surface area is created.

(305) 613. μ-LED according to item 612, characterised in that the smooth surface region comprises a roughness in the range of less than 20 nanometres, in particular less than 1 nanometre, as mean roughness value.

(306) 614. μ-LED to any of the preceding items, wherein the out-coupling structure comprises a transparent third material with a low refractive index, in particular SiO.sub.2, on a roughened first material of the semiconductor of the device.

(307) 615. μ-LED according to any of the preceding items, in which the output coupling structure comprises a transparent third material of low refractive index, in particular SiO.sub.2, on a roughened transparent second material of high refractive index, in particular Nb.sub.2O.sub.5, the second material being attached to a first material of the semiconductor of the device.

(308) 616. μ-LED according to any of the preceding items, in which the output structure comprises a transparent third material of low refractive index, in particular SiO.sub.2, on a transparent second material of high refractive index, the second material being attached to a first material of the semiconductor of the device and comprising periodic photonic crystals or non-periodic photonic structures, in particular quasi-periodic or deterministic aperiodic photonic structures.

(309) 617. Converter element for an optoelectronic component, which has at least one layer comprising a converter material which, when excited by an incident excitation radiation, emits a converted radiation into an emission region,

(310) characterized in that the layer has at least in some areas a structure on which the converter material is arranged at least in sections and which is configured in such a way that the radiation is emitted as a directed beam of rays into the emission area.

(311) 618. Converter element according to item 617,

(312) characterised in that the structure is quasi-periodic or deterministically aperiodic.

(313) 619. Converter element according to item 617 or 618,

(314) characterised in that the layer comprises at least one photonic crystal, a quasi-periodic photonic structure or a deterministically aperiodic photonic structure.

(315) 620. Converter element according to any of the preceding items,

(316) characterised in that the structure comprises at least one recess in which the converter material is located.

(317) 621. Converter element according to any of the preceding items,

(318) characterised in that the layer comprises an optical band gap.

(319) 622. Converter element according to any of the preceding items,

(320) characterized in that the structure comprises an average thickness of at least 500 nm.

(321) 623. Converter element according to any of the preceding items,

(322) characterized in that the layer with the structure is configured such that the directed beam of rays is emitted perpendicularly to a plane in which the layer is arranged.

(323) 624. Converter element according to any of the preceding items,

(324) characterized in that an optical filter element is arranged at least on one side of the layer.

(325) 625. Light-shaping structure for an optoelectronic device comprising at least one layer with a converter material which, when excited by an incident excitation radiation, emits a converted radiation into an emission region

(326) characterized in that the layer has at least in some areas a structure on which the converter material is arranged at least in sections and which is configured in such a way that the radiation is emitted as a directed beam of rays into the emission area.

(327) 626. Light-shaping structure according to item 625,

(328) characterised in that the structure is quasi-periodic or deterministically aperiodic.

(329) 627. Light-shaping structure according to item 625 or 626,

(330) characterised in that the layer comprises at least one photonic crystal, a quasi-periodic photonic structure or a deterministically aperiodic photonic structure.

(331) 628. Light-shaping structure according to any of the preceding items,

(332) characterised in that the structure comprises at least one recess in which the converter material is located.

(333) 629. Light-shaping structure according to any of the preceding items,

(334) characterised in that the layer comprises an optical band gap.

(335) 630. Light-shaping structure according to any of the preceding items,

(336) characterized in that the structure comprises an average thickness of at least 500 nm.

(337) 631. Light-shaping structure according to any of the preceding items,

(338) characterized in that the layer with the structure is configured such that the directed beam of rays is emitted perpendicularly to a plane in which the layer is arranged.

(339) 632. Light-shaping structure according to any of the preceding items,

(340) characterized in that an optical filter element is arranged at least on one side of the layer.

(341) 633. μ-LED arrangement comprising a μ-LED and a converter element according to any of the preceding items, wherein the μ-LED is adapted to radiate an excitation radiation into the converter element, and wherein the converter element comprises at least one layer comprising a converter material.

(342) 634. μ-LED arrangement comprising a μ-LED and having a light-shaping structure according to any of the preceding items, wherein the μ-LED is adapted to irradiate an excitation radiation into the light-shaping structure, and wherein the light-shaping structure comprises at least one layer comprising a converter material.

(343) 635. μ-LED arrangement according to item 633 or 634,

(344) characterized in that the layer is part of a semiconductor substrate of the μ-LED.

(345) 636. μ-LED arrangement according to any of the items 633 to 635,

(346) characterized in that the structure of the converter element or light-shaping structure is formed in the semiconductor substrate of the μ-LED.

(347) 637. μ-LED arrangement according to any of the items 633 to 636,

(348) characterized in that the structure with the converter material is configured in such a way that the converted radiation is emitted into the emission region perpendicular to a plane in which the semiconductor substrate is arranged.

(349) 638. μ-LED arrangement according to any of the items 633 to 637,

(350) characterised in that the structure of the converter element or light-shaping structure is at least partially disposed in an active layer of the μ-LED.

(351) 639. Method for producing a μ-LED arrangement according to any of the items 633 to 638,

(352) characterized in that the structure of the converter element or the light-shaping structure is formed by at least one etching step in a semiconductor substrate of the μ-LED.

(353) 640. Method according to item 639,

(354) characterised in that the structure of the converter element or light-shaping structure is at least partially filled with the converter material.

(355) 641. Optoelectronic device or μ-LED array, comprising:

(356) an arrangement comprising a plurality of μ-LEDs for generating light emerging from a light exit surface from the optoelectronic device, and

(357) at least one photonic structure arranged between the light-emitting surface and the plurality of μ-LEDs.

(358) 642. Optoelectronic device according to item 641, in which the photonic structure is configured for beam-shaping of the light generated by the μ-LEDs, in particular in such a way that the light emerges at least substantially perpendicularly from the light exit surface.

(359) 643. Optoelectronic device according to any of the preceding items, in which the photonic structure comprises a photonic crystal.

(360) 644. Optoelectronic device according to any of the preceding items, in which

(361) the arrangement is an array in which the μ-LEDs represent a plurality of pixels and are arranged in a layer, and in that a photonic structure is arranged or formed in the layer.

(362) 645. Optoelectronic device according to any of the preceding items, characterized in that

(363) the arrangement is an array in which the μ-LEDs represent a plurality of pixels arranged in a first layer and in that a photonic crystal is arranged in a further, second layer, the second layer being located between the first layer and the light-emitting surface.

(364) 646. Optoelectronic device according to any of the preceding items, characterized in that

(365) the arrangement comprises a plurality of μ-LEDs arranged in a first layer, and that a photonic crystal is arranged in the further, second layer, the second layer being located between the first layer and the light-emitting surface.

(366) 647. Optoelectronic device according to any of the preceding items, characterized in that

(367) each of the μ-LEDs comprises a recombination zone and the photonic structure is located so close to the recombination zones that the photonic structure changes an optical state density present in the region of the recombination zones, in particular in such a way that a band gap is generated for at least one optical mode with a direction of propagation parallel and/or at a small angle to the light exit surface.

(368) 648. Optoelectronic device according to any of the preceding items, characterized in that

(369) the photonic structure is arranged in relation to a plane parallel to the light-emitting surface independently of the positioning of the light points, and/or

(370) the photonic structure is a two-dimensional photonic crystal, which exhibits a periodic variation of the optical refractive index in two spatial directions perpendicular to each other and spanning the plane.

(371) 649. Optoelectronic device according to any of the preceding items, characterized in that

(372) the photonic structure comprises a plurality of pillar structures extending at least partially between the light-emitting surface and the plurality of μ-LEDs, wherein one pillar is associated with each μ-LED and is aligned with the light-emitting surface when viewed in a direction perpendicular to the light-emitting surface.

(373) 650. Optoelectronic device according to item 649,

(374) characterised in that

(375) the device is an array in which the μ-LEDs represent a plurality of pixels arranged in a first layer and in that the pixels are arranged in a further, second layer, the second layer being located between the first layer and the light-emitting surface.

(376) 651. Optoelectronic device according to item 649,

(377) characterised in that

(378) the device comprises a plurality of μ-LEDs, arranged in a first layer, and that the pillars are arranged or formed in a further, second layer, the second layer being located between the first layer and the light-emitting surface.

(379) 652. Optoelectronic device according to item 649,

(380) characterised in that

(381) the arrangement is an array in which the μ-LEDs represent a plurality of pixels, one pixel being formed by each pillar.

(382) 653. Method for producing an optoelectronic device,

(383) in particular a device according to any of the preceding items, wherein an arrangement comprising a plurality of μ-LEDs is provided or made for generating light emerging from a light exit surface from the optoelectronic device, and

(384) at least one photonic structure is arranged between the light-emitting surface and the plurality of μ-LEDs.

(385) 654. μ-LED arrangement having at least one μ-LED which emits radiation via a light-emitting surface, and having a polarization element which adjoins the light-emitting surface at least in sections and changes a polarization and/or an intensity of a radiation emanating from the μ-LED when the radiation passes through the polarization element,

(386) characterised in that

(387) the polarizing element comprises a photonic structure.

(388) 655. μ-LED arrangement according to item 654, characterized in that

(389) it is a three-dimensional photonic structure and/or that the polarizing element is configured in the form of a layer which is arranged at least in regions on the light-emitting surface.

(390) 656. μ-LED arrangement according to item 654 or 655, in which the μ-LED is a vertical μ-LED with one connecting contact on opposite sides.

(391) 657. μ-LED arrangement according to any of the preceding items,

(392) characterized in that

(393) the μ-LED, which is configured to emit light, in particular red, green, blue, ultraviolet or infrared light, which is irradiated into the polarizing element, and that the polarizing element polarizes the radiation in an oscillation direction when passing through the polarizing element.

(394) 658. μ-LED arrangement according to any of the preceding items, wherein

(395) the polarising element has spiral and/or rod-shaped structural elements.

(396) 659. μ-LED arrangement according to any of the preceding items, wherein

(397) the μ-LED comprises at least one converter element with a converter material which, excited by excitation radiation emanating from the μ-LED, emits converted radiation.

(398) 660. μ-LED arrangement according to any of the preceding items,

(399) characterised in that

(400) the polarizing element comprises at least one three-dimensional photonic crystal.

(401) 661. μ-LED array according to any of the preceding items, wherein

(402) the polarizing element comprises at least two two-dimensional photonic crystals arranged one behind the other along a beam path of the radiation penetrating the polarizing element.

(403) 662. μ-LED array according to any of the preceding items, wherein

(404) the polarizing element has at least two different polarization properties and/or degrees of transmission depending on a wavelength of the radiation passing through the polarizing element.

(405) 663. μ-LED arrangement according to any of the preceding items,

(406) characterised in that

(407) the μ-LED has a converter element with a converter material which, excited by excitation radiation emanating from the μ-LED, emits converted radiation, and in that excitation radiation incident on the polarizing element is polarized differently and/or absorbed to a different extent when passing through the polarizing element compared with converted radiation passing through.

(408) 664. μ-LED arrangement according to any of the preceding items, where

(409) a three-dimensional structure of the polarizing element is at least partially incorporated in a semiconductor layer of the μ-LED adjacent to the light-emitting surface.

(410) 665. μ-LED array according to any of the preceding items, which is a three-dimensional photonic structure and converter material is disposed in the three-dimensional photonic structure.

(411) 666. Method for producing a μ-LED arrangement having at least one μ-LED which emits radiation via a light-emitting surface, and having a polarization element which adjoins the light-emitting surface at least in sections and changes a polarization and/or an intensity of a radiation emanating from the μ-LED when the radiation passes through the polarization element,

(412) characterised in that

(413) an in particular three-dimensional photonic structure, in particular by two-photon lithography or glancing angle deposition, is applied to the light-emitting surface of the μ-LED as polarization element and/or the photonic structure is arranged in a semiconductor layer of the μ-LED adjoining the light-emitting surface.

(414) 667. Method according to item 666, characterized in that

(415) the photonic structure is dimensioned as a function of the wavelength of the radiation emitted by the μ-LED

(416) 668. Use of a μ-LED array according to any of the preceding items in a device for generating three-dimensional images.

(417) 669. Use of a μ-LED array according to any of the preceding items, characterized in that

(418) the μ-LED arrangement is used after one of the objects 654 to 665 for computer-aided generation of three-dimensional images for an augmented reality application.

(419) 670. Optoelectronic component, in particular comprising a μ-LED array

(420) at least one μ-LED which emits electromagnetic radiation via a light emission surface, and

(421) a photonic structure for beam-shaping of the electromagnetic radiation before it exits via the light emission surface,

(422) wherein the photonic structure shapes the electromagnetic radiation such that the electromagnetic radiation has a specific far field.

(423) 671. Optoelectronic component according to item 670, characterized in that

(424) the photonic structure is a one-dimensional photonic structure, in particular a one-dimensional photonic crystal

(425) 672. Optoelectronic component according to item 670 or 671,

(426) characterized in that

(427) the photonic structure is formed, in particular as a one-dimensional photonic crystal, in such a way that the radiated electromagnetic radiation is at least approximately collimated in a first spatial direction.

(428) 673. Optoelectronic component according to item 672, characterized in that

(429) a collimating optical system is arranged downstream of the light exit surface, as viewed in the main radiation direction, the optical system being designed to collimate the electromagnetic radiation in a further, second spatial direction (R2), which is orthogonal to the first spatial direction.

(430) 674. Optoelectronic component according to one of the preceding items, characterized in that

(431) the photonic structure, in particular formed as a one-dimensional photonic crystal, is designed in such a way that a main radiation direction of the electromagnetic radiation runs at an angle to the normal of the light exit surface, the angle being not equal to zero degrees.

(432) 675. Optoelectronic component according to item 674, characterized in that

(433) the photonic structure formed as a one-dimensional photonic crystal is arranged in a layer below the light-emitting surface, wherein the one-dimensional photonic crystal comprises a periodically repeating sequence of two materials with different optical refractive indices extending in a first direction, wherein the materials have abutting interfaces, which are not orthogonal but inclined to the light-emitting surface.

(434) 676. Optoelectronic component according to one of the preceding items, characterized in that

(435) the photonic structure is a two-dimensional photonic structure, in particular a two-dimensional photonic crystal

(436) 677. Optoelectronic component according to item 676, characterized in that

(437) the two-dimensional photonic structure is designed such that the electromagnetic radiation produces a defined, in particular a discrete, pattern in the far field.

(438) 678. Optoelectronic component according to any of the preceding items, characterized in that

(439) the photonic structure is arranged in a layer, in particular a semiconductor layer, below the light emission surface, and/or the photonic structure is formed in a semiconductor layer of the optoelectronic emitter unit, and/or

(440) the optoelectronic emitter unit comprises a converter material layer and the photonic structure is formed in the converter material layer or in a layer between the converter material layer and the light-emitting surface.

(441) 679. Optoelectronic component according to one of the preceding items, characterized in that

(442) the photonic structure, in particular instead of a photonic crystal, is a quasi-periodic or deterministically aperiodic photonic structure.

(443) 680. Surface topography recognition system, with:

(444) an optoelectronic device, comprising:

(445) at least one optoelectronic emitter unit which emits electromagnetic radiation via a light exit surface, and

(446) a photonic structure for beam-shaping of the electromagnetic radiation before it exits via the light emission surface,

(447) wherein the photonic structure shapes the electromagnetic radiation such that the electromagnetic radiation has a specific far field,

(448) wherein the photonic structure is a two-dimensional photonic structure, in particular a two-dimensional photonic crystal, and

(449) wherein the two-dimensional photonic structure is designed such that the electromagnetic radiation generates a defined, in particular a discrete, pattern in the far field, and

(450) wherein said surface topography detection system further comprises

(451) a detection unit, in particular with a camera, which is designed to detect the pattern in the far field

(452) 681. surface topography recognition system according to item 680 characterized in that

(453) it comprises an analysis device adapted to detect a distortion of the pattern with respect to a predetermined reference pattern.

(454) 682. Surface topography detection system according to item 681,

(455) characterized in that

(456) the analysis means is adapted to determine a shape and/or a structure of an object illuminated by the pattern as a function of the distortion detected.

(457) 683. Scanner for scanning an object, comprising at least one optoelectronic component for one of the previous objects.

(458) The description with the help of the exemplary embodiments does not limit the various embodiments shown in the examples to these. Rather, the disclosure depicts several aspects, which can be combined with each other and also with each other. Aspects that relate to processes, for example, can thus also be combined with aspects where light extraction is the main focus. This is also made clear by the various objects shown above.

(459) The invention thus comprises any features and also any combination of features, including in particular any combination of features in the subject-matter and claims, even if that feature or combination is not explicitly specified in the exemplary embodiments.