Optical element, optical system, and vehicle sheet and / or sheet laminate

Abstract

The invention relates to an optical element (28), in particular an optical prism, comprising at least one light-in surface (32), a light guide (33) and at least one light-out surface (34). The at least one light-coupling surface (32) comprises at least one light-diffusing layer (35) and / or at least one double-camber.

Description

Field of the Invention

[0001] The present invention relates to an optical element, and more particularly to an optical prism as described in the preamble of claim 1. Background Art

[0002] Such optical elements are used, for example, in automotive manufacturing and serve as light guiding structures for purposefully redirecting light emitted by a light source and, for example, coupling it into a light conductor layer and / or a window laminate of a vehicle window. Generally, such optical elements are configured as optical prisms, which can be shaped, for example, triangularly and / or wedge-shaped. By using such an optical element, the position and / or orientation of the light source can be freely selected, since by shaping the optical element, a predetermined redirection or commutation of the light can be achieved, for example, orthogonally to the main radiation direction or the main coupling direction of the light source. In addition, known optical elements are often used to collimate light emitted by a light source, that is, to make the light parallel or identically oriented, in order to achieve a uniform light distribution, for example, when coupling the light into a conductor layer in this way. Thereby, the efficiency of light extraction from the optical element into the light conductor layer is increased.

[0003] The vehicle window and / or window laminate illuminated by the provided light conductor layer is particularly used for interior lighting of a vehicle and / or lighting of other spaces. Generally, a plurality of light sources are provided, which are arranged, for example, spaced apart from each other as an LED strip. Here, at least one light source can be assigned to at least one optical element, so that light can be coupled from at least one light source into at least one optical element, light conduction and / or light commutation can be performed within the optical element, and light can be coupled out from the optical element into the light conductor layer.

[0004] It is also known that by providing a curvature on the light coupling surface of the optical element, not only can the light be collimated, but also light bundling can be achieved along a predetermined axis. However, due to predetermined and / or material-related optical properties, the light coupling is limited to the maximum possible coupling angle. This physical limitation is determined by the refractive index of the material, more precisely, by the ratio of the refractive index of air to the refractive index of the material used to manufacture the optical element. That is, starting from the maximum possible coupling angle, total internal reflection occurs on the light coupling surface. Known optical elements are often made of polymethyl methacrylate (PMMA) or thermoplastic polyurethane (PPU), so that the maximum coupling angle is limited to 41° to 42° (measured relative to the angle bisector).

[0005] In known optical elements, this physical limitation results in a uniform light mixing being achieved only very late in the light conductor layer into which light is conducted through the optical element. The farther apart the individual light sources are from one another, the later this light mixing in the light conductor layer occurs. This later light mixing in turn leads to undesired color differences when the light is subsequently optically coupled out of the light conductor layer, and these color differences are perceived as an optical interference quantity. Although reducing the distance between the individual light sources can overcome this problem, this has the disadvantage that more light sources must then be used for this purpose. However, this leads to increased costs. In addition, more installation space is required, and this installation space is available only as a scarce resource, especially in the automotive field. Summary of the Invention

[0006] It is necessary to overcome the above disadvantages. Therefore, a task of the present invention is to improve an optical element, in particular an optical prism, such that a more uniform light mixing and / or an increased light scattering can be achieved in at least one spatial direction.

[0007] This task is solved by the optical element according to claim 1.

[0008] Advantageous embodiments of the present invention are the subject matter of the dependent claims. Within the scope of the present invention, all combinations of at least two features disclosed in the description, the claims and / or the drawings are included. It goes without saying that the description of the optical element relates in an equivalent manner to an optical system according to the present invention and / or a vehicle window pane according to the present invention and / or a window pane laminate according to the present invention, without redundant description thereof. In particular, it should be understood here that a linguistically appropriate reformulation and / or a meaningful replacement of individual concepts within the scope of conventional language practice, in particular the use of synonyms supported by generally recognized language literature, all belong to the scope of this disclosure, without having to be explicitly mentioned in their respective formulations.

[0009] According to the present invention, an optical element is proposed, in particular an optical prism for a vehicle window pane and / or a window pane laminate. The optical element includes at least one light-coupling-in surface, a light guide body, and at least one light-coupling-out surface, wherein the at least one light-coupling-in surface includes at least one light diffusing layer and / or at least one double curvature portion. The light diffusing layer is preferably designed such that the diffusing effect that can be generated thereby scatters light only in one spatial direction. Exemplarily, "roller optics (Walzenoptik)" can be mentioned here. In contrast, a conventional diffusing layer scatters light in all spatial directions.

[0010] Of course, in principle, the light-coupling surface may also include only one arched portion around an axis, and additionally may have a light-diffusing layer. The axis may be a longitudinal axis or a transverse axis. The longitudinal axis and the transverse axis are preferably oriented orthogonally to each other and are respectively oriented orthogonally to the normal axis of at least one light-coupling surface. The transverse axis preferably substantially, i.e., considering a deviation of ±20%, forms the normal of the light-emitting surface of the optical coupler. The arched portion preferably includes a concave arched portion around the transverse axis or a convex arched portion around the longitudinal axis. The name of the arched portion is preferably in terms of the viewing direction from the perspective of the optical element. The light-coupling surface may also be configured as a plane and include a light-diffusing layer. The double arched portion preferably defines a three-dimensional arched portion of the light-coupling surface around at least two extension axes of the optical element.

[0011] Therefore, the inventors have recognized that by changing the shape of the light-coupling surface and / or by providing a diffusing layer, the incident angle of light onto the light-coupling surface can be increased. Here, compared with the shape in the case of known optical elements, the shape of the light-coupling surface is adapted such that the light-coupling surface, which is concave-shaped (viewed from the light source) in the prior art, additionally includes a convex arched portion and thus includes a double arched portion. Therefore, the light-coupling surface is complexly shaped and currently preferably has two arched portions that are different from each other, and these two arched portions are preferably different with respect to their respective reference axes. Since the incident angle of light onto the light-coupling surface is changed due to the complex arched surface and / or due to the diffusing layer, the coupling angle of light into the light conductor layer is increased, so that compared with the prior art, uniform light mixing can be achieved, and preferably uniform light mixing can be achieved during or immediately after light coupling. Therefore, according to the present invention, the light-coupling surface is changed such that a larger coupling angle can be achieved by providing additional arched portions that do not exist in the prior art on and / or at the surface of the light-coupling surface and / or by providing a diffusing layer. For example, if the optical element is made of PMMA or PPU, the coupling angle is no longer limited to 41° to 42° (measured with respect to the angle bisector) as in the prior art, but is increased by additional arched portions and / or a diffusing layer compared thereto.

[0012] Therefore, according to the present invention, there is no increased cost for the light source and / or increased installation space requirement. Similarly, according to the present invention, light losses during light coupling into the optical element and during light coupling out of the optical element into the light conductor layer can be reduced. Overall, according to the present invention, better, especially more uniform color mixing can be achieved within the light conductor layer, especially immediately after light coupling out of the optical element, which is used for light coupling into the light conductor layer. The core idea of the present invention is to achieve a scattering effect and / or a microlens structure through a double arched portion and / or through a diffusing layer for scattering and / or broadening the light from the light source. Thereby, compared with the prior art, the radiation angle in at least one radiation direction can be broadened.

[0013] Compared with the prior art, embodiments of the optical element according to the present invention thus have many advantages. In the prior art, light can only be coupled into the prism through the coupling-in surface of the plane of the prism facing the light source. In this coupling-in manner, there is always a problem of poor light mixing, especially on the edge side, which is caused by the structure of conventional light sources, especially LEDs. That is, such LEDs are usually composed of red, green, and blue light-emitting chips arranged in a row. The colors of these chips are mixed to obtain the desired combined (light) color. Usually, this light mixing is carried out at a certain distance or within a certain distance after the light source. In other words, the light is not mixed immediately after emission, but is mixed at a certain distance in front of the light source.

[0014] Due to this physical fact, the problem in the prior art is that the mixing length or distance is too long, so light mixing occurs only after the light exits from the prism known in the prior art. This results in the possibility of uneven colors being seen in the boundary region between the prism and the light conductor layer in the light conductor layer. This causes an optical interference parameter, which is undesirable for the observer. However, this drawback can be overcome by means of the present invention.

[0015] That is, the inventors have successfully achieved avoiding poor light mixing in the boundary region between the optical element and the light conductor layer into which light is coupled through the optical element by providing a double curvature portion and / or a diffusing layer on the light-coupling surface of the optical element, such that uniform light mixing can also be provided in this boundary region. According to the present invention, this is achieved by providing a double curvature portion, especially by providing a concave curvature portion along an axis of the optical element. Alternatively or additionally, this is achieved by providing a diffusing layer. The concave lens shape is preferably used to scatter and / or further diffuse the light across the width of the optical element when observed in the main emission direction (x direction). This is preferably achieved by increasing the scattering of the light on the light-coupling surface. Then, the greater scattering of the red, green, and blue light cones preferably results in a shortening of the mixing length. Thereby, it can be achieved that the light has been mixed within the optical element or at least when propagating or transitioning from the optical element into the light conductor layer. Therefore, the light mixing preferably occurs earlier than in the prior art. The earlier light mixing is achieved by providing a double lens or a diffusing layer. Thus, according to the present invention, especially complete mixing still occurs in a region that is invisible to the user or operator. This region can also extend into the invisible region of the light conductor layer.

[0016] Here, providing a diffuser layer is an alternative or complementary solution, which can replace the double-curved portion or be used in combination with the double-curved portion. Providing a diffuser layer can be simpler and more cost-beneficial in manufacturing if necessary, because the double-curved portion requires complex injection molds in some cases. In addition, the positioning of an optical element having a double-curved portion, for example, within an adhesive tool, may be more laborious and thereby increase the difficulty of mounting the optical element on a light conductor layer. This may be caused by the following reasons: The complexly curved surface of the optical element cannot be used or can only be used with difficulty as a stop for placement in the tool. In the case of a double-curved portion, it may occur, partly due to the surface curvature, that the distance between the complexly curved coupling-in surface and at least one light source, which can in particular have single red, green, and blue chips, is not constant. Therefore, an optical element having a double-curved portion may be more sensitive to positioning tolerances during assembly. These challenges present in an optical element having a double-curved portion according to the invention do not exist in an optical element having a diffuser layer. However, the double-curved portion also has the above advantages due to its optical properties, so that overall it is a balanced alternative or complementary solution to the diffuser layer.

[0017] Accordingly, the invention relates to an optical element by means of which the color mixing length within an optical element for coupling light into a vehicle window pane for ambient lighting, in particular within a prism optical device, is shortened. Here, the diffuser layer and / or the double-curved portion are designed such that they scatter light asymmetrically, mainly over the entire width of the optical element. Here, due to the shorter color mixing length achievable according to the invention, an optical element with a smaller size design can be used, whereby installation space can be saved. Therefore, less installation space or area is used below the vehicle window pane, on which at least one optical element should be mounted. The concept according to the invention can be particularly preferably utilized to form and / or in combination with any shaped surface geometry.

[0018] In a preferred embodiment, at least one light-coupling-in surface extends along a longitudinal axis and a transverse axis. The longitudinal axis and the transverse axis are preferably oriented orthogonally to each other and are each oriented orthogonally to the normal axis of at least one light-coupling-in surface. The transverse axis preferably forms, essentially, i.e., taking into account a deviation of ±20%, the normal to the light-coupling-out surface. Here, the double-curved portion preferably includes a concave curvature around the transverse axis and a convex curvature around the longitudinal axis. The names of the curvatures are preferably with respect to the viewing direction from the perspective of the optical element.

[0019] In a preferred embodiment, the normal axis forms the axis of symmetry of the double-curved light-coupling entrance surface. Here, this axis of symmetry can be the cone center axis of the radiation cone of at least one light source and / or coincide therewith. The normal axis can also form the axis of symmetry for the light-diffusing layer. With respect to the surface center point of the light-coupling entrance surface, the normal axis preferably describes a surface center normal axis, that is to say, the normal to the light-coupling entrance surface, which extends through the center point of the light-coupling entrance surface. This center point can be the surface center point in one surface dimension or the surface center point with respect to two surface dimensions.

[0020] In a preferred embodiment, the convex and concave arched portions are represented along the main light-coupling-in direction in which the light is oriented parallel to the normal axis or with respect to this main light-coupling-in direction. The main light-coupling-in direction preferably refers to the cone center axis of the radiation cone of at least one light source and / or the axis of symmetry.

[0021] In a preferred embodiment, the light-coupling entrance surface forms a collimating lens that is concave-shaped around the transverse axis and convex-shaped around the longitudinal axis. Through the collimating lens, the direction of the light coupled in via the light-coupling entrance surface can be made the same.

[0022] In a preferred embodiment, the light-diffusing layer includes optical scattering structures, which preferably have structured and / or unstructured optical interference sites and / or optical grating structures and / or Bragg gratings and / or optical scattering sites and / or optical scattering particles and / or a plurality of microlenses and / or nanolenses. In principle, other embodiments can also be envisaged.

[0023] Particularly preferably, the optical scattering structure is configured as follows or has the following characteristics. The optical scattering structure preferably includes an ideal microstructure, which has an annular chain (Toruskette) with a radius of less than 0.5 mm, preferably in the range of 0.1 mm, and a pitch of less than 0.2 mm, in particular 0.1 mm. Here, the preferred microstructure with an annular chain preferably has minimum radii, which are obtained based on the tools used for manufacturing, for example, are all less than 0.1 mm, preferably between 0.07 mm and 0.03 mm, and the pitch is preferably 0.1 mm. The microstructure preferably has a depth of at least 0.01 mm or more. Particularly preferably, the collimating lens formed in this way preferably has a curvature radius of 1.5 mm. Through simulation, optimized values are preferably obtained for the annular chain with a radius of 0.1 mm and a pitch of 0.1 mm. This results in better color mixing.

[0024] The microstructure is preferably recessed in order to ensure easier tool manufacturing and to be able to clearly demarcate the area with the microstructure from the area without such a microstructure. Another advantage is that in this way the microstructure is protected from damage during transportation.

[0025] If the prism is cast, the fabrication of the microstructure is preferably carried out on a corresponding structured area with a surface configuration of a female mold. Alternatively, the fabrication of the microstructure is achieved by a surface treatment carried out after the prism fabrication, for example by etching and / or mechanical post-processing. The casting mold or the tool can have a surface treatment at the corresponding site, for example by means of a laser (femtosecond, picosecond). In particular, the tool can be made of steel material completely or at least in the structured surface or microstructure area. The steel material is preferably suitable for thermochemical treatment, in which the surface is not coated, i.e., there is no coating on the surface, but only hardened while maintaining the geometry unchanged. Thereby, on the one hand, the filling of the microstructure during injection molding is improved. On the other hand, the stability or durability of the tool is also improved. When fabricating the microstructure, lugs or snap joints are preferably produced or machined on the left and right sides of the microstructure, which are used to simplify the operation of assembling the optical element and / or fixing it in the assembly position. In addition, the lugs or snap joints can be considered for positioning the microstructure and / or the optical element.

[0026] In a preferred embodiment, light scattering in at least one predetermined spatial direction is determined by a light diffusing layer, in particular an optical scattering structure and / or a double curvature.

[0027] In a preferred embodiment, the light diffusing layer includes a light diffusing thin film applied to the light coupling-in surface. Alternatively or additionally, the light diffusing layer is embossed and / or printed and / or vapor-deposited / vapor-coated onto the light coupling-in surface and / or produced by heating the surface of the light coupling-in surface. In principle, the light diffusing layer can also be embossed and / or printed and / or vapor-deposited and / or coated onto a film, in particular a laminated film, where the film is in turn applied to the light coupling-in surface.

[0028] In a preferred embodiment, the optical element can be fabricated or constructed by injection molding. The scattering structure is preferably produced during the injection molding step in such a way that the scattering structure exists on the surface of the tool, in particular the tool being a female mold. The surface of the tool can be structured, for example, by laser etching, photolithography, electroforming, and / or printing.

[0029] The invention also relates to a vehicle window pane and / or window pane laminate on which at least one optical element according to one of the above-described and further explained embodiments is arranged.

[0030] The invention also relates to an optical system. The optical system includes at least one optical element according to one of the above-described and further-explained embodiments below and at least one light source, in particular an LED light source. At least one light source is arranged for emitting light, which can be coupled into the optical element via a light-coupling-in surface, wherein the coupled-in light can be conducted to a light-coupling-out surface via a light guide and can be coupled out from the light-coupling-out surface. The light source is preferably arranged for emitting light at a radiation angle, which is preferably pre-given by the physical parameters of the light source. The radiation angle and / or the distance between the light source and the light-coupling-in surface are preferably selected and / or determined such that, when viewed in the direction of the longitudinal axis, the light can be coupled into the light-coupling-in surface over the entire longitudinal extent of the optical element.

[0031] The invention further relates to providing a vehicle window pane and / or a window pane laminate, which includes a light conductor layer and at least one optical system according to the above-described embodiment, wherein at least one optical element is arranged on one side of the light conductor layer, in particular on the inner side, such that the light coupled out from the light-coupling-out surface can be coupled into the light conductor layer.

[0032] The vehicle window pane and / or the window pane laminate according to the invention can in principle be arranged at any position of a motor vehicle and can be designed for different application purposes.

[0033] It goes without saying that the above-described and further-explained embodiments and examples can not only be implemented individually, but also can be implemented with each other in any combination without exceeding the scope of the invention. It is also self-evident that the above-described and further-explained embodiments and examples relate to all embodiments of the invention in an equivalent or at least similar manner without having to be mentioned separately. Description of the Drawings

[0034] Embodiments of the invention are schematically shown in the drawings and are explained below in an exemplary manner. The drawings show:

[0035] Figure 1 A vehicle window pane having a plurality of optical elements;

[0036] Figure 2 A first embodiment of an optical element having a schematically shown light source;

[0037] Figure 3 Show Figure 2 A top view of the optical element shown in

[0038] Figure 4 A cross-sectional view of an exemplary vehicle window pane and an exemplary optical element;

[0039] Figure 5 A second embodiment of an optical element having a schematically shown light source;

[0040] Figure 6 Shows a third embodiment of the optical element in three different variants;

[0041] Figure 7 Shows a fourth embodiment of the optical element in two different variants;

[0042] Figure 8 shows an optical element in the prior art; and

[0043] Figure 9 shows a top view of the optical element in the prior art shown in Figure 8. Detailed Description

[0044] Figure 1 The roof 10 of a motor vehicle (not shown further) is shown. The roof 10 is, by way of example, a panoramic sunroof, which has an adjustable cover element 12 and a fixed roof element 14, which is fixedly, i.e. immovably, connected to the vehicle body. The cover element 12 and the fixed roof element 14 each include a vehicle window pane 15 and / or a window pane laminate. Currently, the vehicle window panes 15 are each configured as laminated safety glass (VSG, Verbundsicherheitsglas), which is provided with an ambient light function. In this regard, the structure of the cover element 12 corresponds to the structure of the fixed roof element 14. In Figure 4 An exemplary structure of the vehicle window pane is shown in more detail.

[0045] The roof elements 12 and 14, which are each configured as a vehicle window pane 15, respectively include a window pane body assembly 13, which includes a window pane outer body 16 and a window pane inner body 18. The window pane outer body 16 is, by way of example, composed of a curved glass plate, which is made, for example, of colored soda-lime glass. It is also conceivable that the window pane outer body 16 is constructed from a plastic element, such as a polycarbonate element. The window pane inner body 18 can likewise be made of inorganic glass, such as soda-lime glass, or of a polymer, such as polycarbonate. In addition, in the present context, the window pane inner body 18 forms a light conductor layer 19, into which the coupled-in light propagates within its volume (see Figure 4 ).

[0046] The window pane outer body 16 and the window pane inner body 18 are connected to each other by at least one lamination layer or connection layer 20, which can be made of a material such as polyvinyl butyral (PVB), ethylene-vinyl acetate (EVA) or thermoplastic polyurethane (TPU). In addition, the connection layer 20 can be clear or completely transparent, or can also be colored. In the present case, the connection layer 20 has a thickness of less than one millimeter, but can also have other thicknesses.

[0047] In the present case, the outer window panel body 16 and the inner window panel body 18 each have a thickness of a few millimeters. The outer window panel body and the inner window panel body form a window panel body assembly 13, which has an outer side 21 facing the vehicle's surrounding environment and an inner side 23 facing the vehicle's interior space. On the inner side 23, the window panel body assembly 13 is provided with lighting devices 22 on both sides with respect to the vertical longitudinal center plane of the roof, and an ambient light function is achieved through these lighting devices.

[0048] The lighting devices 22 currently extend in the vehicle longitudinal direction L (see Figure 1 ), and are arranged opposite to each other in the vehicle width direction B at the corresponding side edges of the cover element 12 or the fixed roof element 14. Each lighting device 22 includes at least one light source 24, which includes an LED assembly, in particular an LED strip and / or an LED light band.

[0049] According to the invention, at least one optical element 28 is arranged on the inner side 23. Through this optical element, the light radiated by at least one light source 24 can first be deflected in the optical element 28 and then coupled into the light conductor layer 19. Currently, the optical element 28 constitutes an optical prism, which extends, for example, stripwise along the length of the corresponding lighting device 22 and currently has a wedge-shaped or triangular cross-section (see Figure 2 and Figure 4 ). Thus, the optical element 28 forms a prism body. The prism body is preferably made of a plastic material by an extrusion process or an injection molding process. In particular, polymethyl methacrylate (PMMA), thermoplastic polyurethane (PPU), polycarbonate (PC), polyamide (PA), cycloolefin copolymer (COC) and / or cycloolefin polymer (COP) can be used as materials, and their refractive indices are, for example, between 1.48 and 1.59. The optical element 28 can be fixed to the window panel body assembly 13 or the inner side 23, for example, through an adhesive layer. A pressure-sensitive adhesive, an optically transparent liquid adhesive, EVA, PVB, TPU, an epoxy resin adhesive or an acrylic adhesive can be used as the material for the adhesive layer. Through such an optical element 28, the at least one light source 24 can be arranged laterally in the main radiation direction or the main coupling direction 30, in particular parallel to the inner side 23 (see Figure 4 ). That is, through the optical element 28, the light of the light source 24 is preferably deflected and collimated or made the same direction, and in this way is coupled into the light conductor layer 19 via the inner side 23.

[0050] The at least one optical element 28 includes at least one light-coupling surface 32, a light guide body 33 and at least one light-emitting surface 34. The light-emitting surface 34 is adhered to the inner side 23 (see Figure 4 ).

[0051] According to the present invention, the optical coupling input surface 32 includes at least one light diffusing layer 35 (see Figure 5 ), and / or at least one double curvature portion, i.e., for example, is multi-curved, wherein each curvature portion is preferably different from each other. According to a possible embodiment of the present invention, at least one optical coupling input surface 32 extends along a longitudinal axis y and a transverse axis z. The longitudinal axis y and the transverse axis z are oriented orthogonally to each other here, and are respectively oriented orthogonally to the normal axis x of at least one optical coupling input surface 32. According to the present invention, the double curvature portion is constructed by a concave curvature portion 36 around the transverse axis z and a convex curvature portion 37 around the longitudinal axis y, wherein these are respectively viewed along the main radiation direction 30 starting from the light source 24. The normal axis x forms the symmetry axis of the double-curved optical coupling input surface 32, see Figure 3 . In Figure 4 , the main radiation direction 30 is oriented parallel to the normal axis x.

[0052] According to Figure 5 shows an embodiment in which the optical coupling input surface 32 includes a light diffusing layer 35. The light diffusing layer 35 in turn includes an optical scattering structure 38. The optical scattering structure 38 can be constructed by a light diffusing thin film applied to the optical coupling input surface 32. In Figure 7 and FIG. 8, the optical scattering structure 38 is shown in more detail exemplarily. Alternatively or additionally, the optical scattering structure 38 and / or the light diffusing layer 35 can be embossed and / or printed and / or vapor-deposited onto the optical coupling input surface 32, and / or be generated by heating the surface of the optical coupling input surface 32. The optical scattering structure 38 preferably has structured and / or unstructured optical interference sites and / or optical grating structures and / or Bragg gratings and / or optical scattering sites and / or optical scattering particles and / or a plurality of microlenses and / or nanolenses. Through the optical scattering structure 38 and / or the double curvature portion, light scattering in at least one predetermined spatial direction x, y, z is determined, wherein, compared with the prior art, the radiation angle is enlarged (see, the radiation angle according to the present invention is greater than 41°, while the radiation angle in the prior art is less than or equal to 41°). As Figure 5 is only schematically shown, the optical coupling input surface 32 does not include a double curvature portion. For example, the optical coupling input surface 32 can be curved only once as known in the prior art in order to direct and / or focus and / or bundle light in this way. Particularly preferably, the light diffusing layer includes an optical scattering structure through which light is scattered substantially or mainly along the y direction, while being scattered only slightly or minimally in the z direction. Therefore, preferably, light is scattered in the y direction through the scattering structure, and no scattering or only minimal scattering occurs in the z direction.

[0053] As Figure 4 and Figure 5Schematically shown, the light source 24 is arranged to emit light at a pre-determined radiation angle, and the light is coupled into the optical element 28 via the light-coupling-in surface 32. The coupled-in light is conducted through the light guide 33 to the light-coupling-out surface 34 and is coupled out from the light-coupling-out surface 34 into the light conductor layer 19. The light is distributed within the light conductor layer 19, wherein an exemplary light path is indicated by reference numeral 40, and the light is coupled out of the light conductor layer 19 through the light-coupling-out layer 39, for example, into the interior space of the vehicle and / or other spaces.

[0054] Figure 6 Another embodiment of the optical element 28 in three different embodiments is shown. When viewed from top to bottom, these embodiments differ in the type and shaping of the light-coupling-in surface 32. Figure 6 In the upper light-coupling-in surface 32 of the three embodiments, it is not arched, but only includes a light diffusing layer 35 with an optical scattering structure 38 schematically represented by shading, for providing scattering according to the present invention. Figure 6 The middle view in shows the light-coupling-in surface 32, which includes only one arch around the y-axis and a light diffusing layer 35 with an optical scattering structure 38 schematically represented by shading. This arch is convex starting from the optical element. According to Figure 6 In the lower embodiment of the optical element 28 in, the light-coupling-in surface 32 includes a double arch according to the present invention and a light diffusing layer 35 with an optical scattering structure 38 schematically represented by shading, that is, a combination composed of two possibilities according to the present invention.

[0055] Figure 7 Two close-up views or detail views of the light diffusing layer 35 are shown, wherein the optical scattering structures 38 are different from each other. For example, in the left illustration, the optical scattering structure 38 is brought into the surface of the light-coupling-in surface 32 of the optical element 28 by laser and has asymmetric sawtooth portions (Zackung) with different heights along the y-axis. In the right illustration of the light diffusing layer 35 of the light-coupling-in surface 32, the optical scattering structure 38 has a symmetric wavy profile along the y-axis. In principle, the light diffusing layer 35 and / or the optical scattering structure 38 can be a linear diffuser. Herein, preferably, through the light diffusing layer 35, the light is mainly scattered and / or diffused in the y-direction, and no scattering or only minimal such scattering occurs in the z-direction. The optical scattering structure 38 can be a micro-structure or a nano-structure. Particularly preferably, the optical scattering structure 38 is formed into the optical element 28 by an internal mold in an injection mold. Alternatively or additionally, the optical scattering structure 38 is manufactured by laser structuring. Alternatively or additionally, the optical scattering structure 38 is formed into the light-coupling-in surface 32 by photolithographic electroforming or imprinting or laminating.

[0056] List of reference numerals

[0057] 10 Roof

[0058] 12 Cover element

[0059] 13 Window panel body assembly

[0060] 14 Fixed roof element

[0061] 15 Vehicle window panel

[0062] 16 Outer window panel body

[0063] 18 Inner window panel body

[0064] 19 Light conductor layer

[0065] 20 Connection layer

[0066] 21 Outer side

[0067] 22 Lighting device

[0068] 23 Inner side

[0069] 24 Light source

[0070] 28 Optical element

[0071] 30 Main radiation direction or main coupling-in direction

[0072] 32 Light coupling-in surface

[0073] 33 Light guide

[0074] 34 Light coupling-out surface

[0075] 35 Light diffusing layer

[0076] 36 Concave arch

[0077] 37 Convex arch

[0078] 38 Optical scattering structure

[0079] 39 Light coupling-out layer

[0080] 40 Light path

[0081] B Vehicle width direction

[0082] L Vehicle longitudinal direction

[0083] x Normal axis

[0084] y Longitudinal axis

[0085] z Transverse axis.

Claims

1. An optical element (28), in particular an optical prism, the optical element comprising at least one light-coupling input surface (32), a light guide (33) and at least one light-coupling output surface (34), characterized in that, The at least one optical coupling input surface (32) includes at least one light diffusing layer (35) and / or at least one double curvature portion.

2. The optical element according to claim 1, characterized in that, The at least one optical coupling input surface (32) extends along a longitudinal axis y and along a transverse axis z, wherein the longitudinal axis y and the transverse axis z are oriented orthogonally to each other and are respectively oriented orthogonally to the normal axis x of the at least one optical coupling input surface (32), wherein the transverse axis z substantially constitutes the normal of the optical coupling output surface (34), and wherein the double curvature portion includes a concave curvature portion (36) around the transverse axis z and a convex curvature portion (37) around the longitudinal axis y.

3. The optical element according to claim 2, characterized in that, The normal axis x constitutes the axis of symmetry of the doubly curved optical coupling input surface (32).

4. The optical element according to claim 2 or 3, characterized in that, The convex curvature portion (36) and the concave curvature portion (37) are represented along the main coupling-in direction (30) of light oriented parallel to the normal axis x.

5. The optical element according to one of claims 2 to 4, characterized in that The optical coupling input surface (32) constitutes a collimating lens shaped concave around the transverse axis z and convex around the longitudinal axis y.

6. The optical element according to one of the above claims, characterized in that The light diffusing layer (35) includes an optical scattering structure (38), which preferably has structured optical interference sites and / or unstructured optical interference sites and / or an optical grid structure and / or a Bragg grid and / or optical scattering sites and / or optical scattering particles and / or a plurality of microlenses and / or nanolenses.

7. The optical element according to one of the above claims, characterized in that, By means of the light diffusing layer (35), in particular the optical scattering structure (38) and / or the double curvature portion, light scattering in at least one pre-determined spatial direction x, y, z is determined.

8. The optical element according to one of the above claims, characterized in that, The light diffusing layer (35) includes a light diffusing thin film applied to the optical coupling input surface (32), and / or the light diffusing layer (35) is embossed and / or printed and / or vapor-deposited onto the optical coupling input surface (32) and / or is produced by heating the surface of the optical coupling input surface (32).

9. A vehicle window pane (15) and / or a window pane laminate, on which at least one optical element (28) according to one of the preceding claims is arranged.

10. An optical system, the optical system comprising at least one optical element according to one of claims 1 to 8 and comprising at least one light source (24), in particular an LED light source, wherein, The light source (24) is arranged to emit light, which can be coupled into the optical element (28) via the optical coupling input surface (32), wherein the coupled-in light can be conducted via the light guide (33) to the optical coupling output surface (34) and can be coupled out from the optical coupling output surface (34).

11. A vehicle window pane (15) and / or a window pane laminate, said vehicle window pane and / or said window pane laminate comprising a light conductor layer (19) and at least one optical system according to claim 10, wherein, The at least one optical element (28) is arranged on one side (23) of the light conductor layer (19) such that the light coupled out from the optical coupling output surface (34) can be coupled into the light conductor layer (19).

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