PATTERNED OPTOELECTRONIC DEVICE

Abstract

The present invention relates to an optoelectronic device comprising a substrate, in particular a cover layer, an optoelectronically active layer and a contacting layer, the outer and/or inner surface of which has a patterned region with a dot structure of cones or inverse cones. With such a dot structure, the optical properties and wetting properties of the optoelectronic device can be advantageously adjusted in a targeted manner. In particular, it is possible to improve light coupling into or light extraction from optoelectronic devices and thus efficiency. The invention also relates to an optoelectronic module, a method of manufacturing an optoelectronic device and the use of a patterned substrate for an optoelectronic device.

Claims

1-30. (canceled)

31. An optoelectronic device (30) comprising a cover layer (32) which has an outer surface (42) and an inner surface (43), wherein the cover layer (32) is at least partially transparent, at least one functional layer which is arranged at least partially on the inner surface (43) of the cover layer (32), wherein the functional layer is an optoelectronically active layer or a contacting layer, characterized in that the outer surface (42) and/or inner surface (43) is formed from a patterned region (28) and an unpatterned region (29), wherein the patterned region (28) comprises a first periodic dot structure, wherein the first dot structure is formed from at least one first interference pixel (10) with a first interference period (p1), wherein the first interference pixel (10) comprises a periodic lattice of at least three cones (46) or inverse cones (14), wherein the interference period (p1) of the first periodic dot structure is in the range of 50 nm to 50 m.

32. The optoelectronic device (30) according to claim 31, wherein the patterned region (28) is formed from the first periodic dot structure, wherein the first periodic dot structure consists of one or more interference pixels arranged with an offset to each other.

33. The optoelectronic device (30) according to claim 31, wherein the patterned region (28) further comprises a second periodic dot structure, wherein the second periodic dot structure is formed of at least one second interference pixel (11) having a second interference period (p2), wherein the second interference pixel (11) comprises a periodic lattice of at least three cones (46) or inverse cones (14) with a second interference period (p2).

34. The optoelectronic device (30) according to claim 31, wherein the patterned region (28) comprises a periodic line structure with an interference period in the micro- or sub-micrometer range.

35. The optoelectronic device (30) according to claim 31, wherein the water contact angle (23) of the outer surface (42) of the cover layer (32) is less than 20 or greater than 130.

36. The optoelectronic device (30) according to claim 31, wherein the cones (46) or inverse cones (14) of the first interference pixel (10) comprise an average structure depth in the statistical mean d50 in the range of 10 nm to 500 nm, preferably of at most 1 m.

37. The optoelectronic device (30) according to claim 31, wherein the first dot structure comprises an aspect ratio of at least 0.5 or at most 0.1.

38. The optoelectronic device (30) according to claim 31, wherein the cones (46) or inverse cones (14) of the patterned region (28) comprise side surfaces (48), wherein the side surfaces (48) comprise a superimposed quasi-periodic line structure or a smooth surface.

39. The optoelectronic device (30) according to claim 31, wherein the base surface (47) of the cone (46) or the inverse cone (14) is circular or elliptical.

40. The optoelectronic device (30) according to claim 31, wherein the cover layer (32) comprises a transmittance in a sub-range of the electromagnetic spectrum of at least 50% for each wavelength in the sub-range, preferably in the range of visible light or near-infrared light.

41. The optoelectronic device (30) according to claim 31, wherein the cover layer (32) comprises a first cover layer and a second cover layer.

42. An optoelectronic module (41), comprising at least two optoelectronic devices (30) according to one of the preceding claims.

43. The optoelectronic module (41) according to claim 42, wherein the cover layer (32) is formed as a single-layer or multi-layer cover layer (32) extending over the optoelectronic module (41).

44. A method of manufacturing an optoelectronic device (30, in particular according to claim 31, comprising the following steps: a) providing a first terminating layer comprising an inner surface (43), b) applying a functional layer, preferably an optoelectronically active layer or a contacting layer, to at least a partial area of the inner surface (43) of the first terminating layer, c) applying a second terminating layer to at least a partial area of the functional layer, wherein the first or the second terminating layer is formed as a cover layer (32) of the optoelectronic device (30), wherein the cover layer (30) comprises an outer surface (42) and an inner surface (43), the outer surface (42) and/or the inner surface (43) of the cover layer (32) being formed from a patterned (28) and an unpatterned region (29), or the outer surface (42) and/or the inner surface (43) of the cover layer (32) being patterned following step (c) so that it is formed from a patterned region (28) and an unpatterned region (29), wherein the functional layer is an optoelectronically active layer or a contacting layer, characterized in that the patterned region (28) comprises a first periodic dot structure wherein the first dot structure is formed of at least a first interference pixel (10) with a first interference period (p1), wherein the first interference pixel (10) comprises a periodic lattice of at least three cones (46) or inverse cones (14), wherein the first interference period (p1) of the first periodic dot structure is in the range of 50 nm to 50 m.

45. The method according to claim 44, wherein a direct laser interference patterning is generated, wherein the first periodic dot structure is generated by superimposing at least three laser beams.

46. The method according to claim 44, wherein the periodic dot structure is first generated on a negative mold by means of a laser interference process and is applied to the cover layer (32) by means of the negative mold.

47. The method according to claim 44, wherein in the laser interference process partial beams are generated by means of a beam splitter element (2) and the interference period (p) of an interference pixel, preferably the first interference period (p1) of the first interference pixel (10), is continuously adjusted by means of a displacement of the beam splitter element (2), wherein preferably the further optical elements are fixed.

48. The method according to claim 44, wherein the periodic dot structure within an interference pixel is generated by applying a single laser pulse by means of single irradiation.

49. The method according to claim 44, wherein a hierarchical structure with a line structure arranged in the cones (46) or inverse cones (14) is generated by means of multiple irradiation of an interference pixel with identical method parameters.

50. The method according to claim 44, wherein a periodic line and/or dot structure superimposed on the first periodic structure is generated by means of a multiple irradiation with varied process parameters.

Description

EXAMPLES OF EMBODIMENTS

[0458] The present invention is explained in more detail using the following figures and examples of embodiments, without limiting the invention to these.

[0459] Herein shows

[0460] FIG. 1: an optoelectronic device in the form of a photovoltaic cell with a cover layer in the form of a contacting layer.

[0461] FIG. 2: An optoelectronic device in the form of a photovoltaic cell with a cover layer in the form of an encapsulation layer.

[0462] FIG. 3: An optoelectronic module comprising several photovoltaic cells with a cover layer formed as an encapsulation layer.

[0463] FIG. 4: A schematic sectional view of a photovoltaic device with structuring on the outer surface of the cover layer.

[0464] FIG. 5: A schematic sectional view of a photovoltaic device with a structure on the inner surface of the cover layer.

[0465] FIG. 6: A schematic sectional view of an LED with structuring on the inner surface of the cover layer

[0466] FIG. 7A: a schematic representation of an inverse cone.

[0467] FIG. 7B: a schematic representation of a cone-like depression with a circular base.

[0468] FIG. 7C: a schematic representation of a cone-like depression with an irregular base.

[0469] FIG. 8: a cumulative structure of the dot structure from a superposition of several interference pixels

[0470] FIG. 9: a dot structure formed from the superposition of several first and second interference pixels

[0471] FIG. 10: a schematic perspective view of an apparatus for carrying out the method according to the invention.

[0472] FIG. 11: a schematic perspective view of an apparatus for carrying out the method according to the invention, which contains a deflecting element (6) for parallelizing the partial beams.

[0473] FIG. 12: a schematic perspective view of an apparatus for carrying out the method according to the invention, which contains a deflecting element (7) for widening the angle of the partial beams relative to the optical axis of the beam path (3).

[0474] FIG. 13A: a schematic perspective view of an apparatus for carrying out the method according to the invention, which contains optical elements (6) with a planar, reflective surface which deflect the partial beams onto the focusing element (4).

[0475] FIG. 13B: a schematic perspective view of an apparatus for carrying out the method according to the invention, which comprises a galvo mirror (9) as an optical element for beam shaping, which permits stationary positioning of the substrate to be patterned during the patterning process.

[0476] FIG. 14: a schematic perspective view of an apparatus for carrying out the method according to the invention, wherein the apparatus contains a polarization element (8) which shifts the phase course of the partial beams relative to one another, wherein [0477] a) the beam splitter element (2) is positioned in the beam path (3) close to the laser radiation source (1). [0478] the beam splitter element (2) is positioned close to the deflecting element (7) in the beam path (3).

[0479] FIG. 15: a schematic view of the interference pixels resulting on the surface or inside the substrate with the width D, and the distribution of the individual interference pixels on the surface or inside the substrate, the interference pixels being shifted relative to one another with the pixel density Pd.

[0480] FIG. 16: a schematic perspective view of the patterned substrate (5) with the generated periodic dot structures, consisting of inverse cones, with dimensions in the micro- and sub-micrometer range, and symbolically the transmission of incident electromagnetic waves with wavelengths greater than the interference period of the generated structures, as well as the diffraction of incident electromagnetic waves with wavelengths in the range of or smaller than the generated structures.

[0481] FIG. 17: a schematic perspective view of an apparatus for carrying out the method according to the invention, which contains as an optical element a galvo mirror (9) with a planar, reflective surface, which deflects the partial beams onto the focusing element (4), and a polygon wheel (91).

[0482] FIG. 18: A graphical representation of the angle of diffraction of incident light versus the wavelength of the incident light for patterned substrates with three different structure widths.

[0483] FIG. 19: a schematic perspective view of the patterned substrate (5) with the generated periodic dot structures, consisting of inverse cones, with dimensions in the micrometer range, on which a quasi-periodic wave structure in the sub-micrometer range is superimposed.

[0484] FIG. 20: a schematic [0485] a) plan view and [0486] b) a sectional view [0487] of a quasi-periodic wave structure in the sub-micrometer range.

[0488] FIG. 21: an optoelectronic device with a cover layer whose inner surface comprises a superposition of a dot structure and a quasi-periodic wave structure and whose outer surface comprises a dot structure.

[0489] FIG. 22: a visualization of the water contact angle

[0490] FIG. 1 shows a perspective, schematic view of an optoelectronic device (30) in the form of a photovoltaic cell (30.1). In this embodiment example, a contacting layer 31 is formed as a cover layer 32. The cover layer (32) is designed as a substrate (5) for sealing off the photovoltaic cell (30.1) from the environment and thus forms an upward seal. In this embodiment example, three cover layers (32) are arranged on the photovoltaic cell (30.1), which are separated from each other by means of contact rails (33), for example made of a metal such as aluminum. The contact bars (33) are electrically connected to a busbar (34), which establishes the electrical connection to an external contact (35).

[0491] Functional layers (36) adjacent to the cover layer (32) are arranged underneath the multiple cover layers (32). These comprise an n-doped layer (37), a p-doped layer (38) and a boundary layer (39) arranged therebetween, as well as a further contacting layer (31) for forming an electrical connection to a further external contact (35).

[0492] In this embodiment example, the cover layer (32) is formed as an at least partially transparent contacting layer 31, which consists, for example, of a transparent conductive oxide (TCO).

[0493] A further embodiment example of an optoelectronic device (30) designed as a photovoltaic device (30.1) is shown in FIG. 2. Here, the cover layer (32) is designed as an encapsulation layer (40) which, as a substrate (5), protects the photovoltaic device (30.1), also photovoltaic cell, from moisture and other environmental influences. The layers (36) adjacent to the cover layer (32) comprise not only the optoelectronically active layers, i.e. in this case the n-doped layer (37), the p-doped layer (38) and the boundary layer (39), but also two contacting layers (31) for establishing the electrical connection to one of the external contacts (35).

[0494] The encapsulation layer (40) forms the cover layer (32) and improves the optical properties and efficiency. The cover layer (32) forms a substrate (5) comprising a periodic dot structure formed by inverse cones (14), in particular a first periodic dot structure. A patterned region (28) is formed by the inverse cones (14). The dot structure arranged on the cover layer (32) thus forms the patterned region (28). Furthermore, the cover layer has an unpatterned region (29) that does not comprise any pegs or other structures. The unpatterned region (29) is therefore the entirety of the surface, which comprises no structures, in particular no dot structures and no line structures. The patterned region is in turn the entirety of the surface, which is patterned. The sum of the patterned region (28) and the unpatterned region (29) therefore forms the entire surface, in particular the outer surface (42) or the inner surface (43).

[0495] An optoelectronic module 41 with a plurality of photovoltaic devices 30.1, also photovoltaic cells, is shown in FIG. 3. Here, the photovoltaic devices 30.1 are electrically connected to each other, with at least some of the photovoltaic devices 30.1 being connected in series to increase the generated voltage. The cover layer 32 comprises an outer surface 42 with inverse cones 14 and is designed here as an encapsulation layer 40, which protects all the photovoltaic cells 30.1 arranged on the module 41 from environmental influences such as moisture. The inverse cones 14 arranged on the outer surface 42 form the patterned region, whereby the unpatterned region 29 is the section of the surface which comprises no structures, here in particular no inverse cones 14. The surface of the cover layer 32, in particular the outer surface 42, is thus completely divided into the patterned region 28 and the unpatterned region 29.

[0496] Preferably, according to a possible embodiment not shown here, one of the contacting layers of the photovoltaic cells is additionally formed as a cover layer with a patterned region 28 comprising cones or inverse cones.

[0497] A schematic sectional view of an optoelectronic device is shown in FIG. 4 to visualize the reduction in reflection due to the trap effect. A cover layer 32 formed as a terminating substrate 5 is shown pointing upwards. Functional layers 36 adjacent to the cover layer 32 are shown below the cover layer 32. The cover layer 32 comprises an outer surface 42 and an inner surface 43, with the outer surface facing away from the functional layers 36 adjacent to the cover layer 32. The inner surface 43 of the cover layer 32 faces the functional layers 36 adjacent to the cover layer 32, i.e. is directly adjacent thereto.

[0498] The outer surface 42 of the cover layer 32 comprises inverse cones 14, with the sectional view lying straight in a row of inverse cones 14. Light 44 incident on the outer surface 42 also partially strikes an interface point 45 arranged within an inverse cone 14, whereby a portion of the light 44 at this interface point 45 is already transmitted through the interface into the interior of the cover layer 32. However, a further portion of the light 44 is reflected and strikes a further interface point 45 arranged within an inverse cone 14. There, too, a portion of the light 44 is transmitted through the interface between the cover layer 32 and the adjacent layer and a smaller portion is reflected. In this embodiment, this reflected portion also reaches a further interface point 45, where again a portion of the light 44 is transmitted. As a result, the total amount of light 44.1 transmitted through the interface can be significantly increased compared to an outer surface 42 without inverse cones 14.

[0499] FIG. 5 shows a sectional view of an optoelectronic device 30 in which the inner surface 43 of the cover layer comprises cones 46. These can be generated, for example, by means of a negative mold comprising inverse cones, which is not shown here.

[0500] The light 44 is also partially reflected here at the interface points 45 and this part is directed to further interface points 45, where the light 44 is transmitted proportionally through the interface in each case, i.e. penetrates into the layers 36 adjacent to the interface 32 and is not reflected at the interface. Thus, here too, the total amount of light 44.1 transmitted through the interface can be increased or the total amount of light 44 reflected at the interface can be reduced.

[0501] A sectional view of an optoelectronic device 30 in the form of an LED 30.2 is shown in FIG. 6. A cover layer 32 with inverse cones 14 arranged on the inner surface 43 is arranged above the functional layers 36 adjacent to the cover layer 32. The light 44 generated within the functional layers 36 adjacent to the cover layer 32 strikes an interface point 45, where it is proportionally reflected and transmitted. The reflected light 44 again strikes one or more further interface points 45, so that the total amount of transmitted light 44.1 is also increased here. As a result, a larger proportion of the generated light 44 is also decoupled from the LED 30.2.

[0502] FIG. 7A shows a schematic view of an inverse cone 14 generated by means of a laser interference process, which has the structure depth x. The base surface 47 of the inverse cone 14 is circular with a diameter d. The side surfaces 48 are smooth.

[0503] A schematic representation of a cone-like depression 49, such as can be generated by means of an etching process using a mask with circular openings, not shown here, is shown in FIG. 7B. Although the base surface 47 shown is circular, the side surfaces 48 are irregular in shape.

[0504] FIG. 7C shows a schematic view of a cone-like depression 49 with an irregular base surface 47 and irregular, completely variable side surfaces 48. Such a depression is generated, for example, during etching without a mask.

[0505] FIG. 8 visualizes the cumulative build-up of the dot structure from a superposition of several interference pixels (10, 11, 12, 13). Each interference pixel (10, 11, 12, 13) consists of several inverse cones (14) introduced into the substrate by means of laser interference patterning.

[0506] Subfigure (A) shows the first interference pixel (10), which has several inverse cones (14, 14.1). Subfigure (B) visualizes a superposition of the first interference pixel (10) and the second interference pixel (11), this superposition consisting of inverse cones (14.1) of the first interference pixel (10) and inverse cones (14.2) of the second interference pixel (11).

[0507] There is an offset (15) between the first interference pixel (10) and the second interference pixel (11), whereby the inverse cones (14.2) of the second interference pixel (11) are displaced by this offset (15) relative to the inverse cones (14.1) of the first interference pixel (10).

[0508] Subfigure (C) visualizes a superposition in which a third interference pixel (12) is additionally superimposed with the first two interference pixels (10, 11). The superimposed structure in subimage (C) thus comprises inverse cones (14.1) of the first interference pixel (10), inverse cones (14.2) of the second interference pixel (11) and inverse cones (14.3) of the third interference pixel (12). In this embodiment example, the third interference pixel (12) is displaced relative to the second interference pixel (11) in the same spatial direction along the x-axis as the second interference pixel (11) is displaced relative to the first interference pixel (10).

[0509] Subfigure (D) shows a superimposition in which a fourth interference pixel (13) is also superimposed, whereby this is shifted in a different spatial direction along the y-axis with respect to the third interference pixel (12). Thus, the section in partial image (D) comprises a point structure consisting of a superposition of four interference pixels (10, 11, 12, 13).

[0510] The graphs, which are arranged below the interference pixels (10, 11, 12, 13), are used to visualize the periodic structures within an interference pixel (10, 11, 12, 13). Due to the formation of the interference pixels (10, 11, 12, 13) via the process of laser interference patterning, i.e. corresponding to the interference image of the laser (partial) beams, each individual interference pixel (10, 11, 12, 13), which has been formed within an illumination or irradiation process within a selected pulse duration, has a periodic arrangement of the inverse cones (14). The spacing of the inverse cones (14.1) of the first interference pixel (10), which results from the spacing of the intensity maxima of the interference image generating the first interference pixel (10), represents the interference period (p.sub.1). The intensity corresponds to the intensity required to generate the inverse cones (14.1) in the interference pattern of the laser (partial) beams. Thus, the distance between the intensity maxima of the interference image corresponds to the interference period (p1). The second interference pixel (11) has a second interference period (p.sub.2).

[0511] FIG. 9 shows a dot structure (16), which is formed from the superposition of several first interference pixels (10) with a first interference period (p.sub.1) and several second interference pixels (11) with a second interference period (p.sub.2). The first interference pixels (10) have inverse cones (14.1), which are shown here with a vertical pattern fill. The second interference pixels (11) have inverse cones (14.2), which are shown with a horizontal pattern fill. The interference period (p.sub.1) of the first interference pixel (10) is smaller than the second interference period (p.sub.2) of the second interference pixel (11).

[0512] In an optional setting of the interference pixels (10, 11) such that the number of inverse cones (14.1, 14.2) within the interference pixels (10, 11) is identical, the area of the interference pixels (10, 11) consequently varies, which is visualized here by the circles. One of the first interference pixels (10) is schematically represented here by all inverse cones (14.1) with vertical pattern filling within the smaller circle. One of the second interference pixels is again visualized by the inverse cones (14.2), which are shown with a horizontal pattern structure, within the larger circle.

[0513] In this case, the plurality of first interference pixels (10) are arranged adjacent to one another with a repetitive offset and the plurality of first interference pixels (10) thus form a pattern with the interference period (p1). Furthermore, the plurality of second interference pixels (11) are arranged adjacent to each other in a repetitive offset manner and the plurality of second interference pixels (11) thus form a pattern with the second interference period (p.sub.2) which differs from the first interference period (p.sub.1).

[0514] The graph below the dot structure (16) visualizes the arrangement of the inverse cones (14.1, 14.2) along a line through the dot structure (16). The maxima of the intensity correspond to the center of the inverse cones (14.1, 14.2). As in FIG. 12, this graph serves to illustrate the principle. The intensity corresponds to the intensity required to generate the inverse cones (14.1, 14.2) in the interference pattern of the laser (partial) beams.

[0515] FIG. 10 visualizes in a first embodiment example the apparatus according to the invention, comprising a laser radiation source (1) for emitting a laser beam. A beam splitter element (2) is located in the beam path (3) of the laser beam behind the laser beam source (1) and is arranged movably in the beam path (3). A focusing element (4) is located in the optical path (3) of the laser beam behind the beam splitter element (2). A holding device, on which a substrate (5), preferably extensive and/or transparent substrate, is mounted, is arranged in the optical path (3) of the laser beam behind the focusing element (4).

[0516] In this embodiment, the laser radiation source (1) emits a pulsed laser beam. In this case, the laser radiation source is a UV laser with a wavelength of 355 nm and a pulse duration of 12 ps. In this embodiment, the radiation profile of the laser radiation source corresponds to a top-hat profile.

[0517] In this embodiment, the beam splitter element (2) corresponds to a diffractive beam splitter element. A diffractive beam splitter element here is a beam splitter element that contains micro- or nanostructures. The beam splitter element (2) divides the laser beam into 4 sub-beams.

[0518] In this embodiment, the focusing element (4) corresponds to a refractive, spherical lens that directs the sub-beams, which run essentially parallel to each other, onto the substrate (5), preferably extensive and/or transparent substrate, in such a way that they interfere there in an interference region. In this embodiment, the interference angle corresponds to 27.2, resulting in a interference period of 550 nm for the periodic dot structure in the same polarization state.

[0519] According to this embodiment example, the extensive substrate is irradiated once, resulting in a processing time per structural unit, i.e. per interference pixel, of 12 ps.

[0520] The substrate (5), preferably extensive and/or transparent substrate, is a glass, in particular a quartz glass, which is mounted on a holding device so that it can be moved in the xy plane, perpendicular to the optical path of the laser beam emitted by the laser radiation source (1).

[0521] FIG. 11 visualizes in a further embodiment the apparatus as described in FIG. 10, additionally comprising a deflecting element (6), which is located in the optical path (3) of the laser after the beam splitter element (2) and the focusing element (4).

[0522] In this embodiment, the deflecting element is a conventional, refractive, convex lens. The sub-beams hit the deflecting element (6) in such a way that they are essentially parallel to each other after passing through the deflecting element. This allows the point at which the sub-beams interfere on the surface or inside the substrate to be adjusted.

[0523] FIG. 12 visualizes in a further embodiment an apparatus based on the setup shown in FIG. 10 and FIG. 11. In addition, this setup comprises a further deflecting element (6), which is arranged in the optical path (3) of the laser between the beam splitter element (2) and the deflecting element (7).

[0524] In this embodiment, the further deflecting element (7) is a conventional, refractive, concave lens. The sub-beams hit the further deflecting element in such a way that their angle to the optical axis of the optical path is widened. This allows the interference angle with which the sub-beams interfere on the surface or inside the substrate, preferably extensive and/or transparent substrate, to be changed.

[0525] In this embodiment, all optical elements apart from the beam splitter element (2) are fixed along the optical axis of the optical path (3). The interference angle of the sub-beams on the substrate is set by moving the beam splitter element (2) along the optical axis of the optical path.

[0526] FIG. 13A shows in a further embodiment an apparatus as in FIG. 12, comprising the optical elements (6) with a planar, reflective surface, which are configured so that they deflect the sub-beams onto the focusing element (4).

[0527] In this embodiment, the at least three sub-beams are deflected onto the substrate at a preferred angle by shifting the optical elements (6). This means that a deflecting element in the form of a lens (reference sign (6) in FIG. 3) can be dispensed with.

[0528] FIG. 13B shows a schematic perspective view of a device according to the invention, which comprises a galvo mirror (9) as an optical element for beam shaping, which allows stationary positioning of the substrate to be patterned during the patterning process.

[0529] FIG. 14 visualizes in a further embodiment an apparatus as in FIG. 12, additionally comprising one polarization element (8) per sub-beam, which are arranged in the optical path (3) of the laser beam between the deflecting element (6) and the focusing element (4).

[0530] The polarization element is arranged in such a way that it changes the polarization of the individual sub-beams in relation to each other in such a way that a change in the interference pattern results.

[0531] This embodiment is shown in two different configurations. In FIG. 14 a), the beam splitter element (2) is positioned close to the laser radiation source (1) in the optical path (3). In FIG. 14 b), the beam splitter element (2) is positioned close to the deflecting element (7) in the optical path (3). In this way, the interference pattern of the interfering sub-beams on the surface of the substrate (5) can be infinitely adjusted without having to move the other optical elements in the setup or the substrate.

[0532] It would also be conceivable for the arrangement to contain an additional optical element for beam shaping, which is arranged in succession of the laser radiation source (1) in the optical path (3) of the laser beam. In this embodiment, the radiation profile of the laser radiation source corresponds to a Gaussian profile. The optical element for beam shaping converts this profile into a top-hat profile.

[0533] FIG. 15 contains a schematic view of the interference pixels resulting on the surface or inside the substrate with the width D, and the distribution of the individual interference pixels on the surface or inside the substrate, whereby the interference pixels are shifted relative to one another with the pixel density Pd.

[0534] In this embodiment, the pixel density Pd is smaller than the width of an interference pixel, D. Thus, by moving the substrate (5) by means of a pulsed laser beam, an extensive homogeneous periodic dot structure can be generated on the surface or in the interior of a substrate, preferably extensive and/or transparent substrate.

[0535] Preferably, the interference pixels applied one after the other are arranged next to each other. In this embodiment, there is an overlap between two interference pixels arranged next to each other. Due to the multiple irradiation, self-organization processes are preferably stimulated within the patterned region, i.e. within the inverse cones 14. This allows a hierarchical structure to be generated efficiently.

[0536] FIG. 16 visualizes the patterned substrate (5) produced by the method according to the invention with the generated periodic dot structures, consisting of inverse cones, with dimensions in the micro- and sub-micrometer range. The transmission of incident electromagnetic waves with wavelengths greater than the interference period of the generated structures and the diffraction of incident electromagnetic waves with wavelengths in the range of or smaller than the generated structures are also symbolically illustrated.

[0537] FIG. 17 shows in a further embodiment an apparatus as in FIG. 13B, comprising the optical element (91) with a planar, reflective surface, which is a polygon wheel that is configured so that it rotates about a marked axis. The incident sub-beams are deflected in such a way that they hit a galvo mirror (9), which directs the beams onto the substrate via a focusing element (4). The rotation of the polygon wheel causes the point at which the beams are focused on the substrate to move along a line during the exposure process. The sub-beams therefore scan the substrate, which leads to an increased process speed.

[0538] FIG. 18 shows a graphical representation of the transmission and diffraction capability of a patterned substrate as a function of the structure width. The diffraction angle of light is shown as a function of its wavelength for structures with three different structure widths. If the wavelength of the incident light is greater than the structure width, the light is completely transmitted. At wavelengths in the range of the structure width or smaller, diffraction occurs. The diffraction angles can be taken from the diagram.

[0539] FIG. 19 visualizes the patterned substrate (5) generated by the method according to the invention with the generated periodic dot structures, consisting of inverse cones, with dimensions in the micrometer range. Superimposed on this periodic dot structure in the micrometer range is a periodic wave structure in the sub-micrometer range, which can also be produced in one production step by the method according to the invention described herein.

[0540] FIG. 20A visualizes a quasi-periodic wave structure in a plan view and FIG. 20B in a sectional view, as it is exhibited by a patterned substrate which can be produced by a method disclosed herein, in particular by a multiple irradiation or by a single irradiation with high intensity. The sectional view of FIG. 14B represents a cross-section through the structure shown in FIG. 14A approximately along the sectional line A-A. Self-organization processes occurring in the materials lead to the formation of wave-shaped structures with wave crests 10 and wave troughs 11 within an area irradiated in this way. The resulting structures generally exhibit a certain periodicity, although defects 12, i.e. irregularities, also occur. Thus, in contrast to a truly periodic structure, such a structure exhibits both deviations in the structure dimensions, in particular in the distances between the wave crests and troughs, and defects, so that the generated wave structure is not homogeneous.

[0541] FIG. 21 shows an optoelectronic device 30 with a cover layer 32. The cover layer 32 comprises an outer surface 42, which seals the optoelectronic device 30 from the environment, and an inner surface 43. The functional layers 36 adjoining the cover layer 32 are adjacent to the inner surface 43. According to this embodiment, the inner surface 43 comprises cones 46 which form a dot structure, wherein a superimposed structure, which is formed here as a quasi-periodic wave structure 19, is arranged on the cones 46. A periodic dot structure of inverse cones 14 is arranged on the outer surface 42, the interference period of the dot structures on the outer surface 42 being significantly smaller than that of the dot structure on the inner surface 43.

[0542] A visualization of the water contact angle 13 is shown in FIG. 22. A liquid 14 is arranged here in droplet form on a substrate 5. Outside the drop of liquid, air is present in the gaseous phase. The water contact angle 13 is the angle between the surface of the substrate 5 and the tangent 16 adjacent to the drop of liquid. The tangent 16 is considered to be in contact with the surface of the substrate 5. To determine the water contact angle 23, a shadow image of a drop of water 24 is usually taken.

LIST OF REFERENCE SIGNS

[0543] 1 laser radiation source [0544] 2 beam splitter element [0545] 3 optical path [0546] 4 focusing element [0547] 5 substrate [0548] 6 further deflecting element [0549] 7 deflecting element [0550] 8 polarization element [0551] 9 focusing mirror or galvo mirror [0552] 31 optical axis [0553] 91 polygon wheel [0554] 10 first interference pixel [0555] 11 second interference pixel [0556] 12 third interference pixel [0557] 13 fourth interference pixel [0558] 14 inverse cones [0559] 14.1 inverse cones of the first interference pixel [0560] 14.1 inverse cones of the second interference pixel [0561] 14.1 inverse cones of the third interference pixel [0562] 14.1 inverse cones of the fourth interference pixel [0563] 15 offset [0564] 16 dot structure [0565] p.sub.1 first interference period [0566] p.sub.2 second interference period [0567] 19 quasi-periodic wave structure [0568] 20 wave crest [0569] 21 wave trough [0570] 22 defect [0571] 23 water contact angle [0572] 24 water droplet [0573] 25 gaseous phase [0574] 26 tangent [0575] A-A cutting line [0576] 28 patterned region [0577] 29 unpatterned region [0578] 30 optoelectronic device [0579] 30.1 photovoltaic cell, photovoltaic device [0580] 30.2 LED (light-emitting diode) [0581] 31 contacting layer [0582] 32 cover layer [0583] 33 metal rail [0584] 34 Busbar [0585] 35 External contact [0586] 36 Functional layers adjacent to the cover layer [0587] 37 n-doped layer [0588] 38 p-doped layer [0589] 39 Boundary layer [0590] 40 Encapsulation layer [0591] 41 optoelectronic module [0592] 42 outer surface [0593] 43 inner surface [0594] 44 light [0595] 44.1 transmitted light [0596] 45 Interface point [0597] 46 cone [0598] 47 base [0599] 48 lateral surface [0600] 49 depression [0601] D width of the interference pixel [0602] Pd pixel density [0603] d diameter [0604] x structure depth