DEVICES FOR PRODUCING LUMINOUS DISTRIBUTIONS WITH OPTICAL WAVEGUIDES

Abstract

Devices for generating a luminous distribution to illuminate an object with an optical waveguide that comprises at least one input coupling element and a plurality of replication regions are provided. The device is configured to provide a luminous distribution. Further provided are a keratometer, a projection device, a microscope, a calibration device, an area lamp, and a window.

Claims

1. A device for generating a luminous distribution for illuminating an object, comprising: an optical waveguide comprising the following optical elements: at least one input coupling element configured to couple light into the optical waveguide as a light beam having an associated beam profile, a plurality of replication regions for replication of the light beam, each configured to receive at least one associated input light beam having an input beam profile and to provide a plurality of associated output light beams having respective output beam profiles, wherein at least one first replication region of the plurality of replication regions is optically coupled with a second replication region of the plurality of replication regions, such that the second replication region is configured to receive at least one of the plurality of associated output light beams of the first replication region as the associated input light beam of the second replication region, and wherein the first replication region is optically coupled with the at least one input coupling element for receiving the light beam as the associated input light beam of the first replication region, the device being configured to couple emitted light from a number of the plurality of replication regions out of the optical waveguide to provide the luminous distribution.

2. The device according to claim 1, wherein the optical waveguide is configured to receive the light having a first modulation, the device being configured such that the luminous distribution has a second modulation, the second modulation having a greater number of extrema than the first modulation.

3. The device according to claim 1, wherein the device does not comprise a spatial light modulator configured to modulate, on the basis of data, light to be coupled into the optical waveguide.

4. The device according to claim 1, wherein at least a subset of the plurality of replication regions provides a partial luminous distribution of the luminous distribution, said partial luminous distribution having effective focusing.

5. The device according to claim 1, wherein the luminous distribution comprises different light beams overlapping at the optical waveguide.

6. The device according to claim 1, wherein at least one of the optical elements is a volume hologram, said volume hologram being positioned straight or at an angle within the optical waveguide and/or multiply exposed.

7. The device according to claim 1, wherein the device comprises a light source assembly, the light source assembly being configured to provide the light and comprising at least one of the following elements: two light sources configured to provide light in different directions and/or in different wavelength ranges and/or to different illumination positions of the at least one input coupling element, a beam splitter, a scanning mirror, a switchable element.

8. The device according to claim 1, wherein the plurality of replication regions comprises a first set of replication regions, which are each optically coupled to one another, and the replication regions of the first set of replication regions being each configured to: provide at least one first associated output beam of the plurality of output light beams to another replication region of the first set of replication regions, and not provide at least one second associated output beam of the plurality of output light beams to another replication region of the first set of replication regions, to obtain a number of emitted beams of the first set of replication regions.

9. The device according to claim 6, wherein the optical coupling has a serial structure.

10. The device according to claim 8, wherein the optical coupling has a tree structure.

11. The device according to claim 8, wherein the plurality of replication regions comprises a second set of replication regions, which are each optically coupled to each other and a subset of which is configured to receive the number of emitted beams of the first set of replication regions as respective input light beams.

12. The device according to claim 11, wherein the optical coupling of the first set of replication regions and/or the second set of replication regions comprises an optical coupling in series and/or the optical coupling comprises a tree structure.

13. The device of claim 1 wherein the optical elements further comprise: at least one output coupling element configured to couple light out of the optical waveguide.

14. The device according to claim 13, wherein the at least one output coupling element and/or the at least one input coupling element comprise one or more other optical elements selected from a group comprising: a lens, a prism, a surface grating, a polarization filter.

15. The device according to claim 4, wherein the luminous distribution is configured such that a plurality of rays from different regions of the optical waveguide are emitted such that the emitted light is effectively focused and/or effectively defocused.

16. The device according to claim 15, wherein the plurality of rays are collimated and/or emitted from the optical guide in discrete angular regions.

17. The device according to claim 13, wherein the at least one output coupling element comprises at least one other optical element configured to generate a pattern of coupled out light.

18. The device according to claim 1, wherein at least one of the optical elements and/or the at least one other optical element is selected from: a diffractive element, a switchable diffractive element, a volume hologram.

19. The device according to claim 1, wherein the at least one input coupling element is configured to perform coupling based on a characteristic of the light, and wherein the replication regions are configured to produce at least two different associated luminous distributions for at least two different characteristics of the light.

20. The device according to claim 1, wherein the device is configured to provide a luminous distribution for illuminating, at variable angles, an object remote from the device, the object having a smaller diameter than the optical waveguide.

21. The device according to claim 20, wherein the device is configured to provide the luminous distribution for the object when the object is located at an angle to a surface normal of the optical waveguide.

22. An optical waveguide system having a plurality of optical waveguides, according to claim 1, the plurality of optical waveguides having a common optical waveguide with an output coupling area, wherein the common optical waveguide has at least one cutout with a cutout area in the output coupling area, and wherein the plurality of devices is arranged such that the luminous distributions of the plurality of devices originate from at least 80% of the output coupling surface without the cutout area.

23. A device according to claim 1, wherein the optical waveguide has first and second sides, and wherein the luminous distribution comprises a first luminous distribution on the first side and a second luminous distribution on the second side of the optical waveguide.

24-41. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0153] The invention is explained in detail below with reference to the drawings on the basis of exemplary embodiments:

[0154] FIG. 1A depicts a device for generating a illumination distribution in accordance with various exemplary embodiments.

[0155] FIG. 1B depicts a device according to FIG. 1A in accordance with another exemplary embodiment.

[0156] FIG. 2 depicts a front view of a device according to FIG. 1A and/or FIG. 1B.

[0157] FIG. 3 depicts an example of a device with a tree structure.

[0158] FIG. 4 depicts another exemplary embodiment of FIG. 1A and FIG. 1B.

[0159] FIG. 5 depicts a further alternative of the device of FIG. 4.

[0160] FIG. 6 depicts devices in accordance with various exemplary embodiments, which are multi-channeled and/or switchable.

[0161] FIG. 7A depicts a side view of a keratometer according to the invention.

[0162] FIG. 7B depicts a front view of the keratometer of FIG. 7A.

[0163] FIG. 8 depicts another exemplary embodiment of a keratometer.

[0164] FIG. 9 to FIG. 12 depict various implementations of keratometry devices.

[0165] FIG. 13A and FIG. 13B depict an alternative implementation of a keratometer with fixation marks.

[0166] FIG. 14 and FIG. 15 depict a microscope in accordance with various exemplary embodiments.

[0167] FIG. 16 depicts a calibration device 150 for an optical apparatus 910 in accordance with various exemplary embodiments.

[0168] FIG. 17 depicts an area lamp 170 comprising a device 100 in accordance with various exemplary embodiments.

[0169] FIG. 18 depicts a window in accordance with an exemplary embodiment.

[0170] FIG. 19 depicts an illumination device for an active eye implant in accordance with an exemplary embodiment.

DETAILED DESCRIPTION OF THE INVENTION

[0171] In the following, various exemplary embodiments will be described in detail. These exemplary embodiments are merely for illustrative purposes and are not to be construed as limiting. For example, a description of an exemplary embodiment with a large number of elements or components should not be interpreted to the effect that all of these elements or components are necessary for implementation. Rather, other exemplary embodiments may include alternative elements or components, fewer elements or components, or additional elements or components. Elements or components of different exemplary embodiments may be combined unless indicated otherwise. Modifications and variations described for one of the exemplary embodiments may also be applicable to other exemplary embodiments.

[0172] The figures aim to illustrate the underlying principles. For example, surface shapes and refractions may be indicated schematically. Refractions may, for instance, be depicted in exaggerated fashion or neglected.

[0173] To avoid repetition, the same or corresponding elements are designated with the same reference numeral in different figures and are not explained more than once.

[0174] First, two exemplary embodiments of the device are explained with reference to FIG. 1A, FIG. 1B, and FIG. 2.

[0175] FIG. 1A depicts a device for generating a illumination distribution in accordance with an exemplary embodiment.

[0176] The device 100 comprises an optical waveguide 400 having an input coupling element 440. The device 100 is configured to receive light 210 from a light source 203 and emit emitted light 610 in form of a illumination distribution 200. The illumination distribution may be used to illuminate an object. In the depicted example of FIG. 1A and FIG. 1B the illumination distribution has effective focusing, which is indicated by the arrows of the illumination distribution 200 converging towards one another. In other examples, the illumination distribution may also have effective defocusing. In such cases, the arrows indicating the illumination distribution 200 would diverge and would have a virtual starting point on the left-hand side of the optical waveguide 400 in FIG. 1.

[0177] In other examples, the illumination distribution 200 may be configured such that a plurality of beams from different regions of the optical waveguide 400 are emitted such that the emitted light is effectively focused and/or effectively defocused.

[0178] For example, light from the upper half of the optical waveguide 400 could have effective focusing and light from the lower half of the optical waveguide 400 could have effective defocusing.

[0179] FIG. 1B depicts a device according to FIG. 1A in accordance with another exemplary embodiment.

[0180] In the exemplary embodiments of FIG. 1A and FIG. 1B, the light 210 is collimated by a collimator 213 before it hits the input coupling element 440. A collimated light ray may be advantageous for some input coupling elements and, for example, increase coupling efficiency. Collimation may be achieved by a separate collimator 213, as shown in the example of FIG. 1B. In other exemplary embodiments that are not shown, collimation may also be achieved by the input coupling element itself.

[0181] The light 210 has a beam profile 215 with a first modulation 216. The device 100 converts the light 210 into the illumination distribution 200. The illumination distribution 200 has a second modulation 218. Here, the number of extrema of the second modulation 218 is greater than the number of extrema of the first modulation 216. As indicated, at least one of the first and second modulations may be determined in position space (vector “x”) or in angular space (“φ”). In other words, the modulation may be observed in that the intensity is variable as a function of one or more spatial coordinates and/or as a function of one or more angular coordinates, the number of extrema for the second modulation 218 being greater than for the first modulation 216. Here, the coordinates may be normalized expediently, for example in relation to a hemisphere of a unit sphere when light is incident on an object from one side or in relation to a beam diameter in position space.

[0182] In the example of FIG. 1B, the beam profile 215 has a number of one maximum and two minima in relation to the beam diameter. On the other hand, the second modulation 218 of the illumination distribution 200 has 4 maxima and 5 minima, respectively. Thus, the second modulation 218 has a greater number of extrema than the first modulation 216.

[0183] The device can thus convert a relatively simple input light distribution into a complex output light distribution.

[0184] FIG. 2 depicts a front view of a device according to FIG. 1A and/or FIG. 1B.

[0185] In the exemplary embodiment of FIG. 2, the optical elements in the optical waveguide 400 are embodied as discrete units. In other exemplary embodiments, these may also be embodied continuously, as described above and below. an input coupling element 440 is optically coupled to a plurality of replication regions 500, the optical coupling 600 being indicated as an arrow. Each element of the plurality of replication regions 500 is configured to receive an associated input light beam having an input beam profile and to provide a plurality of associated output light beams having respective output beam profiles.

[0186] It is also possible for the light to interact several times with a replication region, for example after a total reflection within the optical waveguide.

[0187] In particular, a first replication region 501 of the plurality of replication regions 500 is optically coupled 600 to the at least one input coupling element 440, such that the first replication region 501 is configured to receive the light beam as the associated input light beam 300 of the first replication region. Furthermore, the first replication region 501 is optically coupled 600 with a second replication region 502 of the plurality of replication regions 500, such that the second replication region 502 is configured to receive one of the plurality of associated output light beams 310 of the first replication region as the associated input light beam of the second replication region 305.

[0188] The device 100 is configured to couple light 610 emitted from a number of the plurality of replication regions 500 out of the optical waveguide 400 to provide the illumination distribution 200, as depicted in FIG. 1A and FIG. 1B, for example. In this case, the light is emitted from an output coupling region 630 of the optical waveguide 400.

[0189] In the exemplary embodiment shown in FIG. 2, the plurality of replication region 500 comprises a first set of replication regions 510 (highlighted via shading), which are each optically coupled to one another and each forward the light to individual elements of the set—with the exception of the last element of the first set—and distribute it in a different direction to other replication regions that do not belong to the first set of replication regions. In the exemplary embodiment shown, all replication regions belong either to the first set of replication regions or to the number of the plurality of replication regions. In other exemplary embodiments, however, this may be varied as desired.

[0190] By means of such a device 100, the light provided at the input coupling element 440 may advantageously be converted into an illumination distribution.

[0191] FIG. 3 depicts an example of a device with a tree structure.

[0192] Here, FIG. 3 shows a detailed view of a device 100, which is also arranged in an optical waveguide. Corresponding to the illustration in FIG. 2, a plurality of replication regions 500 is shown schematically, a first replication region 501 being optically coupled to an input coupling element 440. Further elements of the plurality of replication region have a tree structure 530.

[0193] The replication regions 500 may here be configured both for the transfer of light in the optical waveguide as well as for coupling of light out of the optical waveguide in order to generate an illumination distribution. The degrees of freedom of the illumination distribution that can be generated by a device 100 are further increased by the tree structure.

[0194] FIG. 4 depicts another exemplary embodiment of FIG. 1A and FIG. 1B.

[0195] FIG. 4 shows an exemplary embodiment of a device 100, wherein the reference numerals agree with the devices of FIG. 1A and FIG. 1B. The device 100 of FIG. 4 is configured to provide an illumination distribution 200 to illuminate an object 700. In the exemplary embodiment shown in FIG. 4, the illumination distribution 200 is configured such that a plurality of rays 285 are emitted from different regions of the optical waveguide 400.

[0196] In other words, the illumination distribution comprises different light beams, for example the rays 285 which overlap at the waveguide 400. A portion of the waveguide 400 may also be the origin of light beams having different directions. For example, this may be achieved by means of multiply exposed volume holograms that are used as replication regions and/or output coupling elements.

[0197] As a result, the received light is effectively focused onto the object 700 by the device 100. In the exemplary embodiment shown, the rays 285 are collimated and are emitted from the optical guide 400 with discrete angular regions.

[0198] The optical waveguide 400 may here comprise at least one output coupling element. For example, for each of the plurality of rays 285 a respective output coupling element may be provided. In this case, each of the respective output coupling elements may receive light from several replication regions.

[0199] FIG. 5 illustrates another device 100. This device corresponds essentially to the device of FIG. 4. The device of FIG. 5 is also configured to illuminate the object 700 at the same angles as the device 100 in FIG. 4, but at a greater distance between the object 700 and the optical waveguide 400. Accordingly, the device 100 of FIG. 5 is realized larger than the device 100 of FIG. 4.

[0200] By comparing FIG. 4 and FIG. 5, it can be seen that it may be necessary to increase the diameter of the waveguide when an object with a given diameter is to be illuminated at a greater distance with the same or a similar illumination distribution.

[0201] FIG. 6 depicts devices in accordance with various exemplary embodiments, which are multi-channeled and/or switchable.

[0202] Here, subfigures FIGS. 6(a) to 6(g) depict different examples of multi-channeled or switchable devices which are configured to provide different illumination distributions.

[0203] Various concepts of multi-channel waveguide systems are described below with reference to the devices 100 at (a) to (g). The concepts may utilize high spectral and/or angular selectivity of diffractive elements, for example of volume holograms or other microstructured optical elements in order to be able to transmit several beams of rays independently of one another within the same volume of the optical guide 400. High spectral selectivity refers here to a decrease in the efficiency of the element, for example, by 50% half width, sometimes also known as full width at half maximum (FWHM), with wavelength deviations from the design wavelength, for example <40 nm, for example <10 nm.

[0204] High angular selectivity refers to a decrease in the efficiency of the element by 50% FWHM with a deviation of the beam incidence angle from a design angle for which the respective optical element is designed, for example to receive an associated input light beam from this angle, for example <10°, for example <2°. In these cases, but not limited thereto, several beams of rays with different directions and/or wavelengths may propagate within the same volume of the optical waveguide 400 and may be selectively coupled and transferred by associated optical elements, sometimes also described as “matching” optical elements. In other words, selectively acting replication regions may be provided within an identical volume of the optical guide 400. These may function in superposition and convert the light into different illumination distributions for different characteristics, for example angles of incidence. This is sometimes also described as multiplexing, for example as spectral multiplexing, if the optical elements, for example volume holograms, are configured in such a way that they have different coupling behaviors for different spectral properties of the light. Other types of multiplexing are also possible, for example angle-dependent or polarization-dependent multiplexing, as well as combinations thereof.

[0205] This basic idea will be briefly explained below using the example of side views of device 100 in FIG. 6. Only a maximum of two light sources are shown here by way of example; this is of course not to be interpreted as restrictive; more complex systems, for example with more than two light sources, are also possible.

[0206] The device at (a) depicts a device 100 which is configured to receive light from a first light source 203 with a first wavelength λ1 and light of a second wavelength λ2 from a second light source 204, and to generate a illumination distribution 200 for each received wavelength. In the example shown, the illumination distribution 200 comprises a illumination distribution, which is composed of the illumination distribution 200 of FIG. 4 and a illumination distribution with fixation marks 230. Such a structure may have the advantage that it is possible to use the same optical waveguide 400 in different wavelength ranges to provide different illumination distributions for different purposes, in the example shown, for example, the fixation marks 230 at a wavelength λ2 of the second light source 204 in the visible range and infrared light at a wavelength λ1 of the first light source 203 in the infrared range.

[0207] FIG. 6(b) shows an alternative implementation of the device of FIG. 6(a) with a differently configured input coupling element 440. In this embodiment, the input coupling element 440 comprises two different regions, with a first coupling region 440A configured to couple the light from the first light source 203 and a second coupling region 440B configured to couple the light from the second light source 203 into the optical waveguide 400.

[0208] FIGS. 6(c) to 6(g) show various possibilities for realizing switchable systems and/or systems that allow to overlay, sometimes also referred as superpose, several illumination distributions.

[0209] In the example of FIG. 6(c), the light sources 203, 204 are arranged laterally offset and are coupled into the optical waveguide 400 at different positions by input coupling elements 440A, 440B.

[0210] The respective associated input coupling elements 440A, 440B may be designed in such a way that even with light sources 203, 204 of the same type, different couplings into the optical waveguide 400 are achieved, for example different coupling angles. The device 100 can thus be configured to provide two illumination distributions, in the example shown one illumination distribution for each respective light source. In some examples, these illumination distributions may be selected independently of one another, for example on the basis of the previously described angular selectivity and/or wavelength selectivity of the optical elements used.

[0211] FIG. 6(d) depicts a variation of FIG. 6(c), the two light sources 204, 203 impinging onto an input coupling element 440 at different angles. This input coupling element is configured to couple the two light sources into the optical waveguide 400 independently of one another. In the example of FIG. 6(e), there is only one light source 203. Here, the angle of incidence of the light from the light source 203 is varied by a scanning mirror 460, which results in a switchable illumination distribution. In the example of FIG. 6(f), a switchable optical element 470, for example a switchable hologram, is present within the optical waveguide 400. This also enables to achieve a superposition of different illumination distributions. In the example of FIG. 6(g), a polarization changing element 480 changes the polarization properties of the light from the light source 203. The optical elements of the device 100 may have polarization-dependent properties, so that different illumination distributions may also be effected by varying the polarization of the light incident onto the device 100.

[0212] The examples shown in FIGS. 6(a) to 6(g) may also be combined with one another. For example, different light sources with different polarization directions corresponding to the example in FIG. 6(g) may be combined with a scanning mirror as shown in FIG. 6(e). However, any other combinations of the elements and procedures shown are also possible.

[0213] In connection with the following Figures, various possible applications of the devices shown thus far will be illustrated further.

[0214] FIG. 7A to FIG. 13B show devices according to the invention which are used to provide a keratometer. FIG. 14 and FIG. 15 depict various structures for a microscope in accordance with various exemplary embodiments. FIG. 16 shows a calibration device for an optical apparatus, FIGS. 17 and 18 show devices for area illumination and a window for a building.

[0215] FIG. 7A depicts a side view of a keratometer according to the invention. FIG. 7B depicts a front view.

[0216] With a device 100 according to the invention, a illumination distribution 200 for keratometric measurement of the cornea of an eye 800 is provided. The light reflected by the cornea of the eye 800 is detected by a detection device 900 along a detection beam path 905 and may then be analyzed in order to infer the topology of the cornea. The optical waveguide 400 of the device 100 has a cutout 420. In order to achieve an illumination distribution 200 suitable for keratometry, which illuminates the entire eye to be examined as far as possible, despite the cutout 420, the light is provided by two light sources 203, 204 and coupled in by two input coupling elements 440, 441. Based on the respective input coupling elements 440, 441, the light is replicated over a plurality of replication regions and is coupled out in the direction of the eye 800 as an illumination distribution 200.

[0217] In the example of the keratometer shown, the surface normal of the optical waveguide is arranged parallel to a main visual axis of the eye 800. In other exemplary embodiments, however, the normal of the optical waveguide may also be arranged barely not parallel to the main visual axis of the eye 800. In this way, for example, reflections can be reduced or avoided.

[0218] FIG. 8 depicts another exemplary embodiment of a keratometer.

[0219] In the device 100 of FIG. 8 there are four input coupling elements 440 to 443. The plurality of replication regions 500 are coupled to one another in such a way that an illumination distribution like the illumination distribution 200 of FIG. 7(a) may be provided by the plurality of replication regions 500.

[0220] FIG. 9 to FIG. 12 depict various implementations of keratometry devices. The devices of FIGS. 9 to 11 each have a cutout 420 in the center of a round optical waveguide 400. In the example of FIG. 9, the light near the cutout 420 is received by a plurality of input coupling elements 440 and transferred in series to a plurality of replication regions, which likewise serve to couple the light out into the direction of the eye 800. FIG. 10 depicts a similar arrangement, whereby the plurality of input coupling elements 440 is not arranged in spatial proximity to the cutout 420, but in the vicinity of the edge of the optical waveguide 400. The light received by the plurality of input coupling elements 440 is transferred in series to the plurality of replication regions. Here, the replication regions may be shaped arbitrarily. In the example shown in FIG. 10, these regions are rectangular in shape, but in the vicinity of the cutout 420 they have a more complex shape, wherein other shapes are also possible and the shapes shown are only exemplary.

[0221] In the exemplary embodiment of FIG. 11, the input coupling elements 440 are again arranged in the vicinity of the cutout 420 in accordance with FIG. 9. The optical coupling of the plurality of replication regions now has a tree structure 530. In this way, homogeneous illumination of the eye can be achieved.

[0222] In the exemplary embodiment of FIG. 12, the light is coupled in via a single input coupling element 440 in the center of the optical waveguide 400. The plurality of replication regions 500 are circularly shaped in the exemplary embodiment in FIG. 12 and overlap one another in the front view. This can be achieved by an offset within the optical waveguide or by a volumetric overlap, for example in the case of volume holograms, as already described above. Due to the angular selectivity of some diffractive elements, it may be possible to provide a well-defined light distribution 200 despite the overlap of the plurality of replication regions 500.

[0223] FIG. 13A and FIG. 13B depict an alternative implementation of a keratometer with fixation marks.

[0224] In the exemplary embodiment of FIG. 13A and FIG. 13B, the optical waveguide 400 has no cutout. The observation by the detection device 900 takes place through the optical waveguide 400. The keratometer 120 may comprise a device 100 according to an exemplary embodiment of FIG. 6. An exemplary embodiment according to FIG. 6(b) is shown here. As described in connection with FIG. 6(b), the two light sources 203, 204 generate two illumination distributions 200, the first light source 203 providing the infrared illumination distribution 200 required for keratometry, and a light source 204 emitting in the visible range providing fixation marks 230. In the side view of FIG. 13B it can be seen that the device 100 has an input coupling element 440a for the infrared light for this purpose, which acts in accordance with the exemplary embodiment of FIG. 2. For the fixation marks, the light from the light source 204 is coupled in by an input coupling element 440b and is coupled out by a replication region 500b to provide the fixation marks 230 as an illumination distribution.

[0225] Another application example from the field of microscopy will be explained below.

[0226] FIG. 14 and FIG. 15 depict a microscope in accordance with various exemplary embodiments.

[0227] The microscope 130 has a sample illumination device 140 and an eyepiece 142. This illumination device comprises a device 100 according to the previous exemplary embodiments and is configured to generate an illumination distribution on a sample 700. In particular, the illumination distribution may be a pattern on the sample 700. For this purpose, the device 100 may be configured to receive light from a light source 205 which can be modulated in multiple ways. The received light can then be converted into a illumination distribution 200. Here, the light source, which can be modulated in multiple ways, may be arranged on both the side facing away from the microscope, as shown in FIG. 14, but may also be arranged on the side facing towards the microscope, as shown in FIG. 15. In particular, because of the freedom of design of the device 100 an angle-variable illumination of the microscopic sample 700 may be provided. This allows to fulfill illumination requirements in microscopy, such as those occurring in Fourier ptychography, with reduced effort and/or increased quality. The light sources that can be modulated may be switched on a time-selective basis.

[0228] Frequently, beams of rays do not have to be switched individually, but beam groups can be switched on and off to accelerate the image acquisition. Each of these groups of jointly switched beams of rays can also be regarded as one illumination distribution. Here, a illumination distribution may be provided from a light source assembly as described above and below. Some image optimization methods may, for example, already be realized with light from 4 separately switchable illumination distributions. For this, however, it is necessary that each of the four switchable illumination distributions sends light onto the sample from several discrete directions. Such switchable illumination distributions, also for fewer or more than 4 switching states, can be provided according to the invention.

[0229] Another application example will be described below.

[0230] FIG. 16 depicts a calibration device 150 for an optical apparatus 910 in accordance with various exemplary embodiments.

[0231] The device according to various exemplary embodiments may advantageously be employed for calibrating and adjusting optical imaging systems, for example lenses. This may be particularly advantageous in connection with optical apparatus that are difficult to access, for example lenses or other imaging systems, which are located inside machines or which are used in difficult environmental conditions, for example under water or in space.

[0232] In the embodiment of FIG. 16, a planar optical waveguide system 400 is arranged directly in the beam path 290 of an optical apparatus 910. The device 100 is configured to receive light from a light source 205 that can be modulated in multiple ways, and to provide an illumination distribution. However, the light source 205 that can be modulated in multiple ways may also be a light source that cannot be modulated, for example if only a single illumination distribution is needed, for example a single test image.

[0233] This illumination distribution 200 may now be used to carry out the calibration of the optical device 910. For this purpose, in particular, different wavelengths of light from the light source 205 that can be modulated in multiple ways may be provided simultaneously or sequentially in time. Additionally or alternatively, the illumination distribution 200 may be provided in such a way that the light 210 leaves the optical waveguide such that it is incident under well-defined incident light angles into the optical apparatus 910. In this way, the optical apparatus 910 may be calibrated advantageously.

[0234] At the same time, due to the high angular selectivity of the optical elements in the optical waveguide 400, the normal operation of the optical apparatus 910 is not or only negligibly influenced. In the exemplary embodiment shown in FIG. 16 the calibration device 150 is located in a first installation position 930. In particular, such an installation position outside of the optical elements of the optical apparatus 910 may enable a simple exchangeable installation, for example as a filter element.

[0235] Alternatively or additionally, the calibration device 150 may be installed at a position within optical elements of the optical apparatus 910. This may allow an efficient partial calibration of individual optical elements.

[0236] By providing the illumination distribution not in front of, but e.g. between assemblies of the lens, new concepts for testing and adjusting optical apparatus can be implemented. In such cases, the illumination distribution may, for example, represent the nominal wavefront of the optical apparatus that would arise through the upstream subgroups of lenses and a standard test object.

[0237] The installation of these calibration devices such as the calibration device 150 shown may be permanent or temporary. For example, the calibration device may be moved into the beam path for calibration. In other embodiments, it may also remain permanently in the beam path. Here it may be advantageous that, due to the strong wavelength and/or angular selectivity of the devices used, the influence of the calibration device on the beam path of the optical apparatus may be small. In those cases where the device is permanently installed in the beam path, the device can be taken into account in the optical design of the optical apparatus. Due to the high angular and spectral selectivity of the device in the optical waveguide, only narrow spectral subbands may be filtered out by an optical waveguide for a selected field point of the optical apparatus, such that the functionality of the optical apparatus is not or only minimally influenced. At these wavelength bands, the adjustment marks and test patterns may be fed in by reflection with high efficiency.

[0238] The test patterns offered by the device may be displayed in different distances, wavelengths, positions, and shapes. Thereby it is possible to generate several test patterns at the same time with one radiation source. However, several light source assemblies may also be used and/or others of the described procedures may be applied to generate switchable patterns additionally or alternatively.

[0239] FIG. 17 depicts an area lamp 170 comprising a device 100 in accordance with various exemplary embodiments. In the exemplary embodiment of FIG. 17, light is provided from a first light source 203 from a parabolic reflector 218 to an input coupling element 450 of the device 100. As described above, the coupled-in light is transferred by means of a plurality of replication regions within the optical waveguide 400. In the exemplary embodiment in FIG. 17, the illumination distribution 200 is provided by an output coupling element 620. However, other possibilities for providing the light distribution 200, as described above, may also be used. In particular, very small dimensions A of the optical waveguide 400 may be realized here, with a high degree of freedom from the illumination distribution 200 being available at the same time. In the exemplary embodiment depicted in FIG. 17, collimated light is provided as a illumination distribution 200, but other, more complex illumination distributions may also be generated.

[0240] FIG. 18 depicts a window 180 in accordance with various exemplary embodiments. The window 180 comprises window glass 430, with an optical waveguide 400 according to various exemplary embodiments of the device described above. The window 180 further comprises a window frame 190. A light source 203 is arranged within the window frame 190 and not visible in the exemplary embodiment in FIG. 18. The light source 203 is configured to provide infrared light and to provide this to the at least one input coupling element 450 of the device 100. The device 100 in the optical waveguide generates an illumination distribution 200. In this case, the illumination distribution 200 may be provided as a heat source, for example as a heater for a room in a house, on at least one side of the window. In particular, the infrared light provided by the light source 203 may have a maximum intensity in a spectral range from 1 to 10 μm.

[0241] FIG. 19 depicts an illumination device for an active eye implant in accordance with an exemplary embodiment.

[0242] The device 100 is configured to provide light from a light source 203 to an active eye implant in the eye 800 of a user. In this application example, the light is coupled into the optical waveguide 400 by an input coupling element 440. The optical waveguide 400 is arranged diagonally opposite the eye. This may offer aesthetic advantages if the optical waveguide is arranged in a pair of glasses.

[0243] The light propagates within the optical waveguide 440 in total reflection and is coupled put by an output coupling element 620 and provides the illumination distribution 200 to the eye and thus to the eye implant. In the example shown, the light is provided as a plurality of collimated rays, for example as a collimated beam of rays 212. Here, the plurality of collimated rays are effectively focused, since they pass, originating from the optical waveguide 400, through a larger exit area at the optical waveguide than in an imaginary focusing plane (indicated as a dash-dotted line in front of the eye 800).

[0244] Due to the plurality of coupled out rays, it can also be ensured, when the eye is rotated about the eye pivot point 800a, that the eye implant is supplied with light regardless of the viewing direction.

[0245] As already mentioned, the above exemplary embodiments are merely for illustrative purposes and are not to be construed as limiting. In particular, exemplary embodiments may also be combined with one another, partially as well. For example, teachings described as exemplary embodiments in connection with the microscopy application may also be used in connection with general illumination devices, but also in other exemplary embodiments, for example in connection with the exemplary embodiment of the window, when the window is to heat a specific object. As another example, the fixation marks described in connection with the keratometer may also be used to provide fixation marks in a calibration device or a microscope.