WO2024067916A1

WO2024067916A1 - Optical unit for emitting light, and method for producing an optical unit

Info

Publication number: WO2024067916A1
Application number: PCT/DE2023/100706
Authority: WO
Inventors: Tobias WERSIG
Original assignee: polyscale GmbH & Co. KG
Priority date: 2022-10-01
Filing date: 2023-09-22
Publication date: 2024-04-04
Also published as: DE102022125441A1

Abstract

The invention relates to an optical unit (1) for emitting light, comprising a flat, at least partially translucent visible element (4) which is arranged on a visible side (2) of the optical unit (1) and which faces a viewer when the optical unit (1) is used as intended, a flat light guide element (6) which is arranged so as to be surface-parallel to the visible element (4) and has a first refractive index, and a separating layer (8) which separates the visible element (4) and the light guide element (6) and has a second refractive index, wherein the second refractive index is lower than the first refractive index such that a light which is coupled into the light guide element (6) can be decoupled in order to transilluminate the visible element (4), and the separating layer (8) comprises or is an inorganic polymer (23).

Description

Optical unit for emitting light and method for producing an optical unit

The invention relates to an optical unit for emitting light, a headlight or an interior element and a method for producing an optical unit.

Optical units for emitting light are basically known. Optical units usually have a decor or a functional element that faces the viewer and is backlit and/or illuminated with a light guide. The light guide can be a flat element into which a light is coupled using a light source. The light guide must have a higher refractive index than the surroundings of the light guide element in order to enable total reflection at the boundary layer. Furthermore, means must be provided to deflect the light beams at such angles to the boundary layer of the light guide that they can be coupled out of the light guide despite the different refractive indices. These angles must be smaller than a critical angle of total reflection. One approach to realizing such different refractive indices is to distinguish between the light guide and the decor or the Functional element to provide an air layer. Air has a lower refractive index than the commonly used light guides, so total reflection occurs at the interface between the light guide and the air layer if the angle of incidence is greater than the critical angle. A disadvantage of this structure is that this structure is not compact and has poor stability.

Another approach, described for example in DE 10 2014 006 490 B4, is that the decoration facing the viewer has a lower refractive index than the light guide. A disadvantage of this approach is that the selection of the decoration must be made based on the refractive index of the decoration material. Therefore, the choice of materials is limited with this approach.

Another approach, described for example in DE 10 2019 001 333 A1, is that an additional layer is embedded between the decoration facing a viewer and the light guide, which has a lower refractive index than the light guide. A disadvantage of this approach is that available additional layers usually do not have such a low refractive index that the total reflection and the light extraction meet the high technical requirements of modern products. Another disadvantage of the approach described in DE 102019001 333 A1 is that coextruded films have to be arranged on both sides of the light guide in order to enable the desired technical effect of light emission.

EP 2 157 366 A1 , DE 102015 004204 A1 , EP 3631 291 B1 , DE 10 2013 021 600 A1 , DE 10 2014 006 490 B4, DE 10 2014 112 470 B4, DE 10 2019 001 333 A1 , DE 10 2021 001 512 A1 , WO 2021/193591 A1 , WO 2022/025067 A1 and US 2017/0176835 A1 disclose different technical solutions for optical units for emitting light.

There is a requirement from industry to obtain compact, robust and easy-to-manufacture optical units that can be arranged in different viewing areas, especially in vehicles. In particular, the increased trend in the automotive industry to illuminate visible parts is leading to further and particularly higher requirements. It is therefore an object of the invention to provide an optical unit for emitting light, a headlight or an interior element and a method for producing an optical unit, which reduce or eliminate one or more of the disadvantages mentioned. In particular, it is an object of the invention to provide a solution that enables improved illumination of visible parts, in particular functional elements being able to be embedded.

This object is achieved with an optical unit and a method according to the features of the independent patent claims. Further advantageous embodiments of these aspects are specified in the respective dependent patent claims. The features disclosed in the patent claims, the description and the drawings can be combined individually in any technologically reasonable manner, with further embodiments of the invention being shown.

According to a first aspect, the task mentioned at the outset is achieved by an optical unit for emitting light, comprising a flat, at least partially translucent viewing element arranged on a visible side of the optical unit, which faces a viewer when the optical unit is used as intended, a surface parallel to it the viewing element arranged flat light guide element with a first refractive index, and a separating layer separating the viewing element and the light guide element from each other with a second refractive index, the second refractive index being less than the first refractive index, so that light coupled into the light guide element can be coupled out in order to illuminate the viewing element , wherein the separating layer is or comprises an inorganic polymer.

The invention is based, among other things, on the finding that a separating layer comprising or consisting of an inorganic polymer advantageously enables total reflection within the light guide element and at the same time ensures a particularly advantageous coupling out of the light.

A separating layer designed in this way makes the light conduction in the light guide element more efficient because a relatively large angular range at the interface is totally reflected. This is due to the larger difference in refractive index between the light guide element and the separating layer, so that more light can be used in the light guide element. This improves efficiency and energy requirements. In addition, it was found that such a separating layer enables particularly homogeneous light emission and thus better illumination of the viewing element, in particular due to the improved efficiency. The inventor has also found that a refractive index of less than 1.4 and even less than 1.35 can be achieved using the separating layer.

Furthermore, such a separating layer can advantageously be arranged on the light guide element and/or on the viewing element. In addition, it was found that such a separating layer can be made particularly thin, so that the optical unit can be designed to be compact and cost-effective.

The optical unit has the viewing element. The viewing element is flat. A flat viewing element is to be understood in particular as meaning that the thickness or strength of the viewing element is many times smaller than the extents orthogonal to the strength. The viewing element is preferably designed in the form of a film. Orthogonal to the thickness of the viewing element, the latter can extend flatly or unevenly. For example, the viewing element can be convex or concave. In addition, the viewing element can be freely shaped.

The viewing element is at least partially translucent or transparent. Translucent means in particular that the viewing element has partial light transmission. At least partially translucent can also mean that the viewing element is transparent. The at least partially translucent viewing element ensures that the light coupled out of the light guide element and the light passing through the separating layer can also pass through the viewing element and can be perceived from the visible side of the optical unit. The visible side of the optical unit is in particular the side of the optical unit that is in the intended use of the optical unit is directed towards a viewer.

The visible element can be made of metal, wood and/or plastic, for example, or can comprise one or more of these materials. The visible element can also be partially or completely printed and/or coated. The visible element can be a decoration and/or a functional unit. As described in more detail below, the visible element can be a component of a headlight or an interior element.

The optical unit further comprises the flat light guide element with a first refractive index arranged parallel to the surface of the viewing element. The light guide element is preferably designed in the form of a film. In general, a light guide element is understood to be an element that is designed to guide light over a distance. The light is guided by reflection at boundary surfaces of the light guide element, in particular by means of total reflection.

With regard to the geometric design of the light guide element, reference is made to the previous description of the geometric design of the viewing element. The light guide element preferably has a geometry corresponding to the viewing element, i.e. is, for example, flat, uneven and/or freely shaped.

The refractive index is also known as the refractive index or optical density. The refractive index is an optical material property that describes the ratio of the wavelength of light in a vacuum to the wavelength in the respective material. Light is refracted and reflected at the interface between two materials with different refractive indices. This effect is also known as total reflection. In this context, the material with the higher refractive index is called the optically denser one.

The light guide element can consist of or include a transparent plastic. The transparent plastic can be, for example, PMMA, PC, PS, COC, COP. Furthermore, the light guide element can be made of glass or include glass. The optical unit further comprises the separating layer with a second refractive index. The separating layer can, for example, have a separating element or be designed as a separating element. The separating layer is preferably designed in the form of a film. The separating layer separates the viewing element and the light guide element from each other. The separation is in particular an optical separation. The separating layer can in particular be arranged between the light guide element and the viewing element. This separation can, among other things, mean that the material of the viewing element can be designed independently of refractive indices, since only the difference in the refractive indices of the light guide element and separating layer is relevant for the formation of total reflection within the light guide element.

The second refractive index is lower than the first refractive index, so that total reflection occurs within the light guide element and so that the light coupled into the light guide element can be coupled out, in particular by means of outcoupling structures, which cause the light to strike boundary surfaces of the light guide element at a smaller outcoupling angle as a critical angle of total reflection. In particular, the light should strike a side facing the viewing element at a decoupling angle, so that the light is coupled out on this side.

The formation of the optical fiber element and the separating layer with the first refractive index and the second refractive index makes it possible for light coupled into the optical fiber element to be totally reflected in certain angular ranges at the interface between the optical fiber element and the separating layer, whereby a portion of the light can be coupled out in a targeted manner by elements of the optical fiber element which serve to change the direction of propagation of the light in order to illuminate the viewing element.

The viewing element, the light guide element and the separating layer are arranged in particular in such a way that they form a solid bond. It is preferred that the viewing element is connected to the separating layer, in particular over the entire surface, preferably over the entire surface. Furthermore, it is preferred that the light guide element is connected to the separating layer, in particular over the entire area, preferably over the entire area. The separating layer consists of an inorganic polymer or includes an inorganic polymer. The inorganic polymer can be an inorganic substance as such or have inorganic particles. It is preferred that the separating layer has a separating layer thickness of more than 550 nm.

It is preferred that the optical unit has outcoupling structures which are arranged and designed to couple out the light from the light guide element. It is particularly preferred that the coupling-out structures are arranged and designed to change the direction of propagation of the light such that it occurs at a steeper angle on an opposite boundary layer of the light guide element, so that it can be coupled out there. The output structures can, for example, be printed onto the light guide element. Furthermore, the output structures can preferably be formed using microstructures. The decoupling structures can be formed, for example, by means of a primary molding process, for example in which the light guide element is produced by means of an injection mold that has a negative structure of the microstructures. Furthermore, the outcoupling structures can be arranged adjacent to the light guide element.

It is preferred that the optical unit has a light source that is arranged and designed to couple the light into the light guide element. The light source can be an LED, for example.

A preferred embodiment variant of the optical unit is characterized in that the inorganic polymer is or comprises a polymer with inorganic particles, in particular nanoparticles, and/or the inorganic polymer is or comprises silicone.

The particles, in particular the nanoparticles, can be hollow. It is preferred that the particles, in particular the nanoparticles, consist of silicon dioxide or include silicon dioxide. The particles have the technical effect that the second refractive index of the separating layer is low. Furthermore, these advantageously enable the arrangement of further elements, for example functional elements, within the optical unit without impairing the optical function of the optical unit. It is preferred that the polymer is made from an acrylate. In a preferred development of the optical unit it is provided that it comprises at least one electrical functional element with a function, which is arranged and designed to provide the function on the visible side. Electrical functional elements are to be arranged advantageously if the total reflection is effected in the light guide element with the separating layer consisting of or comprising the inorganic polymer, since light extraction would be more difficult, particularly with an air layer or less advantageously designed separating layers. In particular, a direct arrangement of the electrical functional element, for example as a heating foil, on the light guide element would lead to unfavorable illumination of the viewing element, so that the separating layer with the inorganic polymer advantageously enables this structure. Furthermore, the separating layer made of or with the inorganic polymer advantageously enables the penetration of electromagnetic radiation that is not perceptible to the human eye. In particular, radar waves can, for example, penetrate the described separating layer particularly well without significantly influencing the technical effect of the radar waves.

In a further preferred development of the optical unit it is provided that the viewing element has the functional element. In particular, it is preferred that the functional element is arranged on a surface of the visible element facing the visible side. Alternatively or additionally, the functional element can be embedded in the visual element at least in sections. Such training makes it possible for the viewing element to have an optical function on the one hand and also the additional function.

In a further preferred embodiment variant of the optical unit it is provided that the function of the functional element is a heating function and the functional element is arranged and designed to heat the viewing element and/or a functional unit adjacent to the viewing element. The functional element can be or include, for example, a heating foil. It is preferred that the heating foil is arranged between the separating layer and the viewing element.

Such an optical unit can be used advantageously for example for a headlight or an interior element, since an unrestricted View of the visible element is required and thus, for example, condensation can be avoided by means of the heating function. Furthermore, the heating function can be preferred for components in a vehicle interior in order to increase interior comfort. Another particularly advantageous feature of this design is that the heating function is provided in addition to the visible side on a side of the optical unit opposite the visible side.

It is preferred that the optical unit has the functional unit. The functional unit can be, for example, a headlight cover or another at least partially translucent or transparent component.

In a further preferred embodiment variant of the optical unit it is provided that the function of the functional element is a sensory function. A sensory function can be provided for a switching element, for example, so that a touch to actuate the switch can be detected.

In a further preferred development of the optical unit it is provided that the separating layer is designed as a coating or comprises it. The coating comprises or consists of the inorganic polymer, in particular the polymer with particles, preferably nanoparticles, and/or silicone. It is preferred that a coating thickness of the coating is between 300 nm and 100 pm, in particular between 500 nm and 10 pm, further preferably between 500 nm and 1.5 pm. Such a coating thickness leads to a particularly advantageous function of the coating, since total reflection is thus advantageously brought about.

A further preferred embodiment variant of the optical unit is characterized in that the inorganic particles, in particular the inorganic nanoparticles, are arranged essentially equally distributed, in particular uniformly distributed, within the polymer. Such an arrangement of the particles, in particular the nanoparticles, within the polymer enables an advantageous formation of the second refractive index, so that total reflection can be further advantageously effected. Substantially uniformly distributed means in particular that the particles within the polymer are arranged uniformly distributed in more than 90%, preferably more than 95%, of a volume of the polymer. A further preferred embodiment variant of the optical unit provides that the separating layer is designed as a separating film comprising the inorganic polymer. For example, the release film can be coated with the inorganic polymer. In addition, the release film can consist of the inorganic polymer.

A further preferred embodiment of the optical unit is characterized in that the light guide element is designed in the form of a film. It is preferred that a light guide element thickness, in particular of the light guide element designed in the form of a film, is less than 2000 pm, in particular less than 1500 pm, preferably less than 1000 pm, preferably less than 500 pm, preferably less than 300 pm. In particular, it is preferred that the light guide element thickness is between 300 pm and 800 pm, further preferably between 500 pm and 800 pm.

In a further preferred embodiment, it is provided that the film-shaped light guide element has coupling-out structures consisting of and/or with a UV-cured coating, in particular a varnish, on a side facing away from the visible element. It is also preferred that these coupling-out structures were produced using a nanoimprint process.

According to a further aspect, the object mentioned at the outset is achieved by a headlight or an interior element, in particular for a vehicle, comprising an optical unit according to one of the embodiments described above. The headlight can, for example, have a headlight cover that is coupled to the optical unit.

The headlight can be, for example, a headlight module or a headlight unit. In particular, it is preferred that the optical unit of the headlight has a functional unit designed as a headlight cover. The headlight can also be part of a front section of a vehicle with further functional modules, for example sensors, in particular radar units, lidar sensors and the like.

The interior element can, for example, be a decorative element for the interior of a vehicle. Furthermore, the interior element can be a dashboard and/or a center console. In addition, the interior element can be a switching element, in particular with a sensor.

According to a further aspect, the object mentioned at the outset is achieved by a method for producing an optical unit, in particular an optical unit according to one of the embodiments described above, comprising the steps of: providing a flat, at least partially translucent viewing element and a flat light guide element with a first refractive index, arranging a separating layer with a second refractive index that is lower than the first refractive index, such that the viewing element and the light guide element are separated from one another, and light coupled into the light guide element can be coupled out in order to illuminate the viewing element, in particular to backlight it, wherein the separating layer is or comprises an inorganic polymer.

In a preferred embodiment of the method, it is provided that the inorganic polymer is or comprises a polymer with inorganic particles, in particular nanoparticles, and/or the inorganic polymer is or comprises silicone.

In a preferred embodiment of the method, it is provided that it comprises the step of arranging at least one functional element for providing a function on the visible side. The functional element can, for example, be arranged on the visible element. Alternatively or additionally, the functional element can be embedded in the visible element.

In a further preferred embodiment variant, the method comprises the step: coating a release film with the inorganic polymer and using the coated release film as a release layer.

The release film can be coated using a printing process or a continuous coating process, for example with a slot die application. It is preferred that the separating film is joined to the light guide element using an injection molding process. The release film can, for example, be back-injected. It is further preferred that a structured molding tool is used in the injection molding process, with which Coupling structures for coupling out light are introduced into the light guide element.

In a further preferred embodiment of the method, this comprises the step: producing coupling-out structures from and/or with a UV-curable coating, in particular a lacquer, on a side of the film-shaped light guide element facing away from the visible element, in particular with a nanoimprint process.

In a further preferred embodiment variant of the method, this includes the steps: thermally forming the separating film to produce a predefined shape of the separating film, and providing the viewing element by means of a primary forming process, in particular an injection molding process, preferably by means of a back-injection process, so that the viewing element is with the thermally formed separating film is connected. For this purpose, for example, the release film can be inserted into a mold and the visible element can be back-injected. It is preferred that a functional element is inserted into the mold.

In a further preferred embodiment of the method, it is provided that it comprises the steps of: coating the visible element with the separating layer and then arranging the light guide element on the separating layer. Arranging the light guide element can be or include, for example, back-injection molding. It is preferred that the method comprises the step of: arranging coupling-out structures on the coated visible element and/or the light guide element. It is further preferred that the coupling-out structures are introduced into the coating using a nanoimprint method. In particular, it is preferred that this is done using a microstructuring method.

A further preferred development of the method is characterized by the steps: heating the optical unit to a predefined temperature and deforming the optical unit by applying a pressure and/or a force to the optical unit. Alternatively, this can be done with a sub-unit of the optical unit, for example by means of a sub-unit consisting of the visible element of the separating layer, in particular the separating film, and/or a Subunit consisting of the light guide element and the separating layer, in particular the separating film.

In a further preferred embodiment variant of the method, this includes the step: applying an additional layer for further functional integration and/or to improve the mechanical properties on the visible side and/or on an opposite side facing away from the visible side.

The additional layer can, for example, be the functional element designed as a heating foil. It is preferred that the heating foil is joined with a film-shaped light guide element to form a functional composite and the functional composite is then back-injected. In particular, the separating layer, preferably the separating film, is arranged between the heating film and the light guide element.

For further advantages, design variants and details of the individual aspects and their possible further training, please refer to the description of the other aspects, the corresponding features and further training.

Preferred embodiments are explained using the accompanying figures. They show:

Figure 1: a schematic, two-dimensional view of an exemplary one

Embodiment of an optical unit;

Figure 2: a schematic, two-dimensional view of a further exemplary embodiment of an optical unit;

Figure 3: a schematic, two-dimensional view of a further exemplary embodiment of an optical unit;

Figure 4: a schematic, two-dimensional view of a process sequence for producing a back-injected composite;

Figure 5: a schematic, two-dimensional view of another exemplary embodiment of an optical unit;

Figure 6: a schematic, two-dimensional view of a further exemplary embodiment of an optical unit; Figure 7: a schematic, two-dimensional view of a further exemplary embodiment of an optical unit;

Figure 8: a schematic view of an exemplary process;

Figure 9: a schematic view of another exemplary one

procedure; and

Figure 10: a schematic view of another exemplary one

procedure.

In the figures, identical or essentially functionally identical or similar elements are designated with the same reference numerals.

Figure 1 shows an optical unit 1, which extends in a thickness direction from a visible side 2 to an opposite side 3. The optical unit 1 extends flatly in the orthogonal direction to the thickness direction. The optical unit 1 has a viewing element 4 adjacent to the visible side 2. When the optical unit 1 is used as intended, the viewing element 4 faces a viewer. A light guide element 6 is arranged adjacent to the opposite side 3. The light guide element 6 is arranged parallel to the surface of the viewing element 4. The light guide element 6 has a first refractive index.

A separating layer 8 is arranged between the viewing element 4 and the light guide element 6, which separates the viewing element 4 and the light guide element 6 from one another. The separating layer 8 has a second refractive index that is lower than the first refractive index. The separating layer 8 consists of an inorganic polymer 23. In this exemplary representation, the inorganic polymer 23 is designed as a polymer with nanoparticles 24.

A light source 10, for example an LED, is arranged laterally adjacent to the light guide element 6 and couples light, for example in the form of a light beam 12, into the light guide element 6. Due to the different refractive indices of the light guide element 6 and the separating layer 8, a total reflection occurs within the light guide element 6, so that the light beam 12 is reflected at the respective boundary layer of the light guide element 6. This is further caused by the fact that the angle with which the light beam 12 striking the interface is larger than a critical angle of total reflection.

In order to decouple the light coupled in by the light source 10 from the light guide element 6, decoupling elements (not shown) are provided which reflect the light beam at such an angle that it hits the boundary layer to the separating layer 8 at an outcoupling angle that is smaller than a critical angle of total reflection and is thereby decoupled. This then passes through the separating layer 8 and illuminates the viewing element 4.

It is further shown that the separating layer 8 comprises a plurality of nanoparticles 24. The nanoparticles 24 are evenly distributed in the polymer.

In Figure 2, the separating layer 8 is formed by means of a separating film 14 and a coating 16. The separating film 14 has the coating 16, wherein the coating 16 consists of the inorganic polymer 23 or comprises the inorganic polymer 23. Here too, the light source 10 couples light into the light guide element 6 in a manner analogous to Figure 1, although this is not shown here.

The separating film 14 can, for example, be provided separately with the coating 16 and then arranged on the visible element 4, in particular connected to it. The light guide element 6 can then be arranged on the separating layer 8.

Figure 3 shows a similar structure to Figure 2, but with the separating film 14 facing the light guide element 6 and the coating 16 facing the viewing element 4.

The process flow for producing an optical unit 1 is shown in FIG. The upper figure shows a composite of a coated carrier film 14, 16 as a separating layer 8 with a viewing element 4. In the middle figure, this composite has been reshaped so that it has a convex shape. In the figure below, this composite of visible element 4 and separating layer 8 has been back-injected with the light guide element 6. This has the advantage that, for example, there are 3 output structures on the opposite side Back-injection processes can be introduced. This can be done, for example, using a microstructured mold.

Figure 5 shows a further embodiment of the optical unit 1. On the opposite side 3, a further separating layer 8' and a further viewing element 4' are arranged, so that the optical unit is functionalized from two sides.

6 shows a similar structure to that in FIG. 5, but a reflection layer 18 is arranged on the separating layer 8 'adjacent to the opposite side 3. With the reflection layer 18, coupled-out light is coupled back into the light guide element 6, so that it can be coupled out on the side of the viewing element 4. The separating layer 8′ between the reflection layer 18 and the light guide element 6 is required in order to avoid immediate coupling out of the light on this side.

Figure 7 shows an optical unit 1 with an electrical functional element 20 that enables a heating function. For example, the functional element 20 can be designed as one, two or more wires through which a current flows. In the present case, the functional element 20 is partially embedded in the visible element 4 and partially arranged on a surface of the visible element 4. A functional unit 22 is arranged on a side of the visible element 4 facing away from the light guide element 6, which can be a headlight cover, for example.

Figure 8 shows an exemplary method for producing an optical unit 1. In step 100, the viewing element 4 and the light guide element 6 are provided. In step 102, the separating layer 8, 8 'is arranged so that the viewing element 4 and the light guide element 6 are separated from one another, and a light coupled into the light guide element 6 can be coupled out in order to backlight and/or illuminate the viewing element 4. The separating layer 8, 8′ is or comprises the inorganic polymer 23.

Figure 9 shows a further embodiment of the method. In step 200, the viewing element 4 and the light guide element 6 are provided in a manner analogous to step 100. In step 202, a separating film 14 is coated with a coating 16 consisting of the inorganic polymer 23. In step 204, the coated separating film 14 is arranged as a separating layer 8, 8', so that it separates the visible element 4 and the light guide element 6 from each other. In particular, the separating film 14 is connected to the visible element 4. The subunit made up of the separating film 14 and the visible element 4 can then be back-injected on the side of the separating film 14 in order to provide the light guide element 6.

Figure 10 shows a further embodiment of the method. In step 300, a film-shaped light guide element 6 is coated with the coating 16 consisting of the inorganic polymer 23 to form the separating layer 8. In step 302, coupling-out structures 26 are produced on the opposite side 3 of the light guide element 6 using a nanoimprint process. For this purpose, a UV-curable varnish is first applied, which is then cured with UV light. Step 302 can also be carried out before step 300.

In step 304, the film-shaped light guide element 6 is connected to a heating film, the heating film being arranged on a side of the light guide element 6 facing away from the opposite side 3. In step 306, the composite thus produced from the light guide element 6 and the heating film is thermally formed in order to produce a predefined shape of the composite. In step 308, the composite is back-injected to produce the visible element 4, so that the visible element 4 is connected to the light guide element 6 and the separating layer 8.

The optical unit 1 described above and the method described have the advantage that improved backlighting or transillumination of a decoration or a functional unit 22 is possible. In particular, the embedding of a functional element 20 is possible without the backlighting or transillumination function being restricted.

REFERENCE SIGNS

1 optical unit

2 Visible side

3 Opposite side 4, 4' viewing element

6 light guide element

8, 8‘ separating layer

10 light source

12 Light beam 14 Separating film

16 coating

18 reflective layer

20 electrical functional element

22 functional unit 23 inorganic polymer

24 nanoparticles

26 output structure

Claims

EXPECTATIONS

1. Optical unit (1) for emitting light, comprising a flat, at least partially translucent viewing element (4) arranged on a visible side (2) of the optical unit (1), which faces a viewer when the optical unit (1) is used as intended, a flat light guide element (6) arranged parallel to the viewing element (4) and having a first refractive index, and a separating layer (8) separating the viewing element (4) and the light guide element (6) from one another and having a second refractive index, wherein the second refractive index is lower than the first refractive index, so that light coupled into the light guide element (6) can be coupled out in order to illuminate the viewing element (4), wherein the separating layer (8) is or comprises an inorganic polymer (23).

2. Optical unit (1) according to claim 1, wherein the inorganic polymer (23) is or comprises a polymer with inorganic particles (24), in particular nanoparticles.

3. Optical unit (1) according to one of the preceding claims, wherein the inorganic polymer (23) is or comprises silicone.

4. Optical unit (1) according to one of the preceding claims, comprising at least one electrical functional element (20) with a function, which is arranged and designed to provide the function on the visible side (2).

5. Optical unit (1) according to one of the preceding claims, wherein the viewing element (4) has the functional element (20), and preferably the functional element (20) is arranged on a surface of the visible element (4) facing the visible side (2), and / or preferably the functional element (20) is at least partially embedded in the visible element (4).

6. Optical unit (1) according to one of the preceding claims, wherein the function of the functional element (20) is a heating function, and the functional element (20) is arranged and designed to heat the viewing element (4) and/or a functional unit (22) adjacent to the viewing element (4).

7. Optical unit (1) according to one of the preceding claims, wherein the separating layer (8) is designed as or comprises a coating (16), and preferably a coating thickness of the coating (16) between 300 nm and 100 pm, in particular between 500 nm and 10 pm, also preferably between 500 nm and 1.5 pm.

8. Optical unit (1) according to one of the preceding claims, wherein the inorganic particles (24) are arranged in a substantially uniform distribution within the polymer.

9. Optical unit (1) according to one of the preceding claims, wherein the separating layer (8) is designed as a separating film (14) comprising the inorganic polymer (23).

10. Optical unit (1) according to one of the preceding claims, wherein the light guide element (6) is designed in the form of a film and preferably has a thickness of less than 2000 pm, in particular less than 1500 pm, preferably less than 1000 pm, preferably less than 500 pm , preferably less than 300 pm. Optical unit (1) according to one of the preceding claims, wherein the film-shaped light guide element (6) has decoupling structures (26) consisting of a UV-cured coating on a side facing away from the viewing element (4). Headlight or interior element, in particular for a vehicle, comprising an optical unit (1) according to one of the preceding claims 1-11. Method for producing an optical unit (1), in particular an optical unit (1) according to one of the preceding claims 1-11, comprising the steps:

Providing a flat, at least partially translucent viewing element (4) and a flat light guide element (6) with a first refractive index;

Arranging a separating layer (8) with a second refractive index that is lower than the first refractive index, such that the viewing element (4) and the light guide element (6) are separated from one another, and a light coupled into the light guide element (6) can be coupled out in order to illuminate the viewing element (4), wherein the separating layer (8) is or comprises an inorganic polymer (23). Method according to the preceding claim 13, wherein the inorganic polymer (23) is or comprises a polymer with inorganic particles (24), in particular nanoparticles. Method according to one of the preceding claims, wherein the inorganic polymer (23) is or comprises silicone. Method according to one of the preceding claims, comprising the step:

Arranging at least one functional element (20) for providing a function on the visible side (2). 17. Method according to one of the preceding claims, comprising the step:

Coating a release film with the inorganic polymer and using the coated release film as a release layer (8).

18. The method according to any one of the preceding claims, wherein the light guide element (6) is provided in the form of a film, comprising the step:

Creating coupling-out structures (26) consisting of a UV-curable coating, in particular a varnish, on a side of the film-shaped light guide element (6) facing away from the visible element (4), in particular using a nanoimprint process.

19. Method according to one of the preceding claims, comprising the steps of: thermally forming the release film to produce a predefined shape of the release film, and

Providing the visible element (4) by means of a primary forming process, in particular an injection molding process, preferably by means of a back-injection molding process, so that the visible element (4) is connected to the thermally formed release film.

20. Method according to one of the preceding claims, comprising the steps:

Coating the visible element (4) with the separating layer (8) and then arranging the light guide element (6) on the separating layer (8).

21. Method according to one of the preceding claims, comprising the steps:

Heating the optical unit to a predefined temperature, and deforming the optical unit by applying pressure and/or force to the optical unit.

22. Method according to one of the preceding claims, comprising the step:

Applying an additional layer for further functional integration and/or to improve the mechanical Properties on the visible side (2) and/or on one of the visible sides

(2) opposite side (3).