Light guide

Abstract

The utility model relates to a light guide member, the light guide member has a bending structure and comprises a bottom surface and a light emitting surface which are opposite to each other, the light guide member is provided with a plurality of optical microstructures recessed from the bottom surface, and the plurality of optical microstructures form a preset pattern. The plurality of optical microstructures are arranged on the substrate, so that light propagating in the substrate passes through the plurality of optical microstructures, then the propagation direction is changed, and the light is emitted from the light-emitting surface so as to present the preset pattern on the light-emitting surface, and supporting pieces are arranged in at least one part of the plurality of optical microstructures; the support is arranged to at least partially maintain the morphology of the plurality of optical microstructures during the formation of the curved configuration of the substrate. According to the utility model, the light guide member is provided with the bending structure, the light emitting mechanism of the optical microstructure area can be ensured, and the higher light emitting efficiency can be ensured as far as possible, so that an observer can normally observe the preset pattern formed by the optical microstructure.

Description

TECHNICAL FIELD

[0001] The utility model relates to light guide technical field. More specifically, the utility model relates to a light guide with a curved structure. BACKGROUND

[0002] Currently, some vehicles are provided with light-emitting trim parts on interior trim parts (for example, door panels, instrument panels, ceilings, etc.) to display patterns on these interior trim parts as needed. These light-emitting trim parts include, for example Figure 1 As shown in the light guide, the base body 100' of the light guide includes a bottom surface 110 and a light-emitting surface 120 opposite to each other, and a plurality of optical microstructures 130, for example, recessed from the bottom surface 110, are formed on the bottom surface 110 by some process means (including but not limited to embossing, screen printing, pad printing, laser engraving, UV offset printing, etc.). These optical microstructures 130 form a preset pattern as a whole, so that the light propagating in the base body 100' can change the propagation direction and be emitted from the light-emitting surface 120 after passing through the optical microstructures 130, thereby enabling the observer 200 to observe the preset pattern on the light-emitting surface 120. That is, due to the presence of the optical microstructures 130, the total reflection mechanism of the region is destroyed, and thus light emission can be achieved through the light-emitting surface 120.

[0003] However, the main defect of the above-mentioned light guide is that, as shown in Figure 2 When the base body 100' of the light guide is bent according to the needs by various forming processes or mounting methods, the optical microstructures 130 thereon will be deformed obviously, for example, the optical microstructures 130 will be obviously shallower or even disappear, which destroys the light emission mechanism of the region, makes it difficult to maintain sufficient light emission efficiency, and causes the observer to be unable to normally observe the preset pattern formed by the optical microstructures 130. SUMMARY

[0004] The utility model aims to overcome at least one defect in the prior art. More specifically, the light guide according to the utility model has a curved structure and can ensure the light emission mechanism of the optical microstructure region, as far as possible to ensure a high light emission efficiency, so that the observer can normally observe the preset pattern formed by the optical microstructure.

[0005] To this end, the utility model provides a light guide piece, including base body, the base body has the curved structure and includes the bottom surface and the light emitting surface opposite to each other, wherein, a plurality of optical microstructures recessed from the bottom surface are formed on the base body, the plurality of optical microstructures form the preset pattern, so that the light propagating in the base body changes the propagation direction after passing through the plurality of optical microstructures and shoots from the light emitting surface to present the preset pattern on the light emitting surface, and the light guide piece further includes the support arranged in the inside of at least a part of optical microstructures in the plurality of optical microstructures, the support is arranged to at least partially maintain the form of the plurality of optical microstructures during the base body forms the curved structure.

[0006] According to the above technical concept, the utility model can further include any one or more of the following optional forms.

[0007] In some optional forms, the thickness of the base body is between 100 μm and 6000 μm, and / or the maximum depth of each optical microstructure in the plurality of optical microstructures recessed from the bottom surface is between 5 μm and 20 μm.

[0008] In some optional forms, the shape of each optical microstructure in the plurality of optical microstructures is arranged as a hemisphere, a crater, a wedge or a pyramid.

[0009] In some optional forms, the base body has a single curvature structure or a double curvature structure.

[0010] In some optional forms, the base body includes at least one curved segment, and the inner radius of curvature of the curved segment is greater than or equal to twice the thickness of the base body.

[0011] In some optional forms, the base body further includes at least one flat segment extending from the curved segment, and the plurality of optical microstructures are arranged in the curved segment and / or the flat segment.

[0012] In some optional forms, the support is arranged to accommodate a solid slurry inside the optical microstructure.

[0013] In some optional forms, the slurry is a nano-silver slurry or a nano-copper slurry.

[0014] In some optional forms, the volume of the slurry accounts for at least 30% of the volume of the corresponding optical microstructure.

[0015] In some optional forms, the support is a plating layer at least partially covering the inner wall of the optical microstructure.

[0016] In some optional forms, the material of the base body is polycarbonate, polymethyl methacrylate or thermoplastic polyurethane.

[0017] In some optional forms, the light guide comprises a plurality of substrates, the plurality of substrates are arranged in layers, and the optical microstructures on at least two substrates are respectively provided with different preset patterns.

[0018] In some optional forms, the two adjacent substrates are closely attached to each other.

[0019] In some optional forms, the light guide comprises at least one curved segment, and the inner radius of curvature of the curved segment is greater than or equal to 2 mm.

[0020] In some optional forms, the light guide comprises at least one curved segment, and the inner radius of curvature of the curved segment is greater than or equal to twice the thickness of the substrate with the inner radius of curvature.

[0021] In some optional forms, the light guide is a light guide plate or a flexible light guide film.

[0022] Compared with the prior art, the light guide according to the utility model has a plurality of beneficial technical effects, especially: for the light guide, by filling the support in the optical microstructure of the substrate, the shape of the optical microstructure can be at least partially maintained as much as possible after bending, so that the light emission mechanism of the region is guaranteed, and the desired ideal light emission efficiency is obtained, so that the observer can still normally observe the preset pattern formed by the optical microstructure through the light emission surface. In addition, the light guide structure is simple, convenient to form, and low in cost, so that it can be widely applied in various types of vehicle ornaments. BRIEF DESCRIPTION OF DRAWINGS

[0023] Other features and advantages of the utility model will be better understood through the following preferred embodiments described in detail in conjunction with the drawings. In the drawings, the same reference signs represent the same or similar parts.

[0024] Figure 1 is a light path schematic view of a light guide in the prior art.

[0025] Figure 2 is a schematic view of the light guide in Figure 1 before bending and deforming.

[0026] Figure 3 is a schematic view of a plurality of shapes of optical microstructures on the light guide.

[0027] Figure 4 is a schematic view of a light guide according to an embodiment of the utility model.

[0028] Figure 5 is a schematic view of the light guide in Figure 4 before bending and deforming.

[0029] Figure 6 These are schematic diagrams of two types of light guides with curved structures.

[0030] Figure 7 These are schematic diagrams of two other light guides with curved structures.

[0031] Figure 8 yes Figure 5 A schematic diagram of two bending deformation modes of the light guide component.

[0032] Figure 9 yes Figure 5 A schematic diagram of the deformation of the optical microstructure of the light guide component.

[0033] Figure 10 yes Figure 9 An enlarged view of the boxed area in the diagram.

[0034] Figure 11 This is a schematic diagram of a multilayer light guide according to one embodiment of the present invention.

[0035] Figure 12 This is a schematic diagram of a 3D light guide component according to one embodiment of the present invention.

[0036] Figure 13 It is along Figure 12 A schematic diagram of the cross section taken from plane AA.

[0037] The elements in the accompanying drawings are shown for simplicity and clarity and are not necessarily drawn to precise scale or shape. It should be understood that the drawings are not only used for explanation and illustration of the present invention, but also, where necessary, to limit the present invention. Detailed Implementation

[0038] The implementation and use of specific embodiments are discussed in detail below. However, it should be understood that the specific embodiments discussed are merely illustrative of particular ways of implementing and using this utility model, and are not intended to limit the scope of this utility model.

[0039] This utility model relates to a light guide with a curved structure and a preset pattern. The light guide can be a light guide plate with relatively high rigidity or a light guide film made of flexible material; this utility model does not limit the choice. Specifically, when the light guide is applied to vehicle trim, it usually needs to be manufactured with partial or overall bending to match the structure of the trim, the installation environment, and the desired pattern effect. Bending a flat light guide can be achieved by using simple fasteners during installation, or by using processes such as high-pressure molding, vacuum forming, or hot bending to create a more complex structure. Therefore, specific design is needed to maintain the light emission mechanism of the light-emitting area after bending, ensuring high light emission efficiency so that the observer can still normally observe the preset pattern on its light-emitting surface.

[0040] The preferred embodiment of the light guide of this utility model will now be described with reference to the accompanying drawings.

[0041] like Figures 3 to 5 As shown, the light guide according to this utility model includes a substrate 100, which has a curved structure formed by bending a flat piece, and includes a bottom surface 110 and a light-emitting surface 120 facing each other. A plurality of optical microstructures 130 recessed from the bottom surface 110 are formed on the substrate 100, and these optical microstructures 130 collectively form a preset pattern desired by the manufacturer. The material of the substrate 100 can be, but is not limited to, PC (polycarbonate), PMMA (polymethyl methacrylate), TPU (thermoplastic polyurethane), etc. The methods for forming the optical microstructures 130 on the substrate 100 can include, but are not limited to, embossing, screen printing, laser engraving, UV offset printing, etc.

[0042] More specifically, before bending, the substrate 100 has the following properties: Figure 5 The generally flat plate-like or thin-film structure shown disrupts the total internal reflection mechanism in this region due to the arrangement of optical microstructures 130. Light propagating within the substrate 100 can change its propagation direction after passing through these optical microstructures 130 and exit from the light-emitting surface 120, thereby allowing an observer to observe a predetermined pattern formed by these optical microstructures 130 on the light-emitting surface 120. For example... Figure 3 As shown, the thickness T of the substrate 100 is typically between 100 μm and 6000 μm, for example, about 200 μm for a light guide film, and / or, the maximum depth h of each optical microstructure 130 recessed from the bottom surface 110 of the substrate 100 is typically between 5 μm and 20 μm, for example, about 15 μm. Furthermore, the shape of each optical microstructure 130 is not limiting and can be as follows: Figure 3The shapes shown schematically from left to right are crater-shaped, wedge-shaped, hemispherical, or any other suitable shape such as a pyramid (i.e., a triangular pyramid).

[0043] To suit the structure of vehicle trim, installation environment, pattern effects, or other requirements, light guides are, for example, bent into shapes such as... Figure 4 The configuration shown is such that, after bending, the bottom surface 110 where the optical microstructure 130 is formed is located on the inside, i.e., having a smaller bending radius, while the opposite light-emitting surface 120 is located on the outside, i.e., having a larger bending radius, thus the optical microstructure region is bent inward. According to one embodiment, after bending, the bottom surface 110 where the optical microstructure 130 is formed may also be located on the outside, i.e., having a larger bending radius, while the opposite light-emitting surface 120 is located on the inside, i.e., having a smaller bending radius, thus the optical microstructure region is bent outward (e.g., see reference). Figures 8 to 10 ).

[0044] It is understandable that the area where the optical microstructures 130 are located is prone to deformation after the light guide is bent, thereby affecting the light extraction efficiency. Therefore, according to this invention, in order to avoid the destruction of the light extraction mechanism in this area due to the significant deformation of the optical microstructures 130 after the light guide is bent through various processes or installation methods, the light guide also includes a support member 140 disposed inside at least a portion of the optical microstructures 130, preferably disposed inside each optical microstructure 130. Due to the provision of the support member 140, the shape of these optical microstructures 130 can be maintained at least partially during the bending process of the substrate 100 (and therefore after bending), for example, at least partially maintaining the shape, curvature, area, and other characteristics of these optical microstructures 130, thus ensuring the light extraction mechanism in this area and obtaining the desired ideal light extraction efficiency. In other words, even if the substrate 100 is bent, the light propagating in the substrate 100 can still change its propagation direction after passing through these optical microstructures 130 and be emitted from the light-emitting surface 120, so as to clearly present the preset pattern formed by these optical microstructures 130 on the light-emitting surface 120.

[0045] Figure 6 and Figure 7 Several light guides with different curvature structures are illustrated schematically. It is understood that these light guides can be formed into a single-curved structure (i.e., a surface with zero Gaussian curvature, which is "flat" in at least one direction, also known as a 2.5D structure) by means of simple fasteners during installation or by processes such as autoforming, vacuum forming, and hot bending; or they can be formed into a hyperbolic structure (i.e., a surface with non-zero Gaussian curvature, which has curvature in both principal directions, also known as a 3D structure) by means of processes such as autoforming, vacuum forming, and hot bending.Figure 6 and Figure 7 As shown, the substrate 100 of each light guide includes at least one curved segment A1, the bending radius of which determines the bending effect. To ensure that the substrate 100 maintains its light guiding characteristics and light emission characteristics of the optical microstructure region after bending, the inner bending radius R of the curved segment A1 is typically required to be greater than or equal to twice the thickness T of the substrate 100, i.e., R ≥ 2T. Furthermore, some light guide substrates 100 also include at least one flat segment A2 extending from the curved segment A1, such as two flat segments A2 extending from both ends of the curved segment A1. The curved segment A1 is the restricted arrangement area for the optical microstructure, and the flat segment A2 is the ideal arrangement area for the optical microstructure. In principle, the optical microstructure can be placed in the curved segment A1 and / or the flat segment A2; that is, the optical microstructure can be arranged in both the ideal and restricted arrangement areas. However, in the restricted arrangement area, the specific parameters of the optical microstructure and its supporting components must be considered to avoid significant deformation of the optical microstructure after bending, which could damage the light emission mechanism.

[0046] According to one embodiment, the support 140 can be a solid paste housed within the optical microstructure 130. The paste used can be, but is not limited to, nano-metal pastes. Preferably, the paste used is nano-silver paste or nano-copper paste. Such pastes provide both an anti-reflective effect (i.e., the material itself has high reflectivity, allowing more light to be reflected) and a stable support for the optical microstructure 130, preventing significant deformation of the optical microstructure 130. It is understood that the material, particle size, and filling process (coating method, curing conditions, etc.) of the paste are not limited and can be selected according to actual needs. It is understood that when the substrate 100 is in a flat state, the characteristics of the paste itself will cause some attenuation in the emitted light brightness (e.g., a 5%-70% reduction) compared to the unfilled substrate 100, and this attenuation is usually unavoidable. It is also understood that the selected paste requires the difference between its refractive index after curing and the refractive index of the substrate 100 to reach a desired predetermined value to ensure the light emission mechanism at the optical microstructure 130.

[0047] After the slurry is filled and bent relative to the substrate 100, without considering the attenuation caused by the characteristics of the slurry itself, the filling volume (i.e., coverage) of the slurry in the optical microstructure 130 has the greatest impact on the light extraction efficiency. For example... Figure 8 As shown, ignoring the influence of the slurry's inherent properties on luminous efficacy, bending of the substrate 100 will cause deformation of the optical microstructure 130, resulting in luminous loss. However, the area filled with the slurry will maintain its original luminous efficiency, and the volume of filling is directly proportional to the luminous efficiency (relative brightness). Figure 8From left to right (refer to 140a, 140b, 140c), the larger the volume of the filled slurry, the higher the light extraction efficiency. For example... Figure 9 and Figure 10 As shown, taking the outward bending of the optical microstructure region as an example, the actual filling region in the shown cross-section can be equivalently represented by the ideal filling region S bounded by the inner wall portion 131 of the optical microstructure 130 and the dashed line L (at the inner wall edge 132 of the optical microstructure 130, the filling paste is too thin to protect the shape of the optical microstructure 130). The ideal filling region S of the optical microstructure 130 can basically maintain its shape after bending, thus ensuring the light extraction mechanism at this location; however, outside the ideal filling region, the optical microstructure 130 undergoes significant deformation after bending, affecting the light extraction mechanism at this location. Therefore, it can be approximately considered that the light extraction efficiency maintenance rate of the optical microstructure region before and after bending is approximately equal to the proportion of the volume of the ideal filling region S to the volume of the optical microstructure 130 (i.e., the light extraction efficiency maintenance rate after bending ≈ the volume of the ideal filling region S / the total volume of the optical microstructure 130). Optionally, the volume of the paste accounts for at least 30% of the corresponding volume of the optical microstructure 130, more preferably at least 50%. Therefore, in the optical microstructure region, due to the filling of slurry, the light emission efficiency after bending can reach at least 50% of the original light emission efficiency (i.e., the light emission efficiency of the flat part). This can be regarded as maintaining the light emission mechanism of the region, so that the observer can clearly observe the preset pattern formed by the optical microstructure through the light emission surface.

[0048] According to another embodiment, the support 140 may also be a coating layer that at least partially covers the inner wall of the optical microstructure 130. For example, a PVD (physical vapor deposition) process can be used to coat the inner wall of the optical microstructure 130 to provide support for the optical microstructure 130. It is understood that the coating may be applied to the entire bottom surface 110 of the substrate 100, or only to the area of ​​the bottom surface 110 that includes at least a portion of the optical microstructure 130.

[0049] This invention can also be applied to multi-layer stacking scenarios. For example... Figure 11As shown, the light guide, including at least one curved section, comprises multiple substrates, such as the first substrate 100a, the second substrate 100b, and the third substrate 100c shown. These three substrates are stacked and preferably arranged such that adjacent substrates are closely fitted together. Typically, at least two substrates are provided with optical microstructures of the type described above, and the optical microstructures of these at least two substrates form different preset patterns. For example, each substrate is provided with optical microstructures of the type described above, and the optical microstructures of each substrate form different preset patterns relative to the other substrates. In this way, light can be selectively incident on one or more of these substrates according to different needs, thereby displaying different patterns and increasing the premium feel of the vehicle trim. Furthermore, light can be incident sequentially into each substrate in a cyclic or random manner, causing the light guide to exhibit a dynamic light-emitting effect.

[0050] In such multi-layered light guides, for some single-curved (2.5D) applications, the bending shape can be achieved directly through structural installation and the flexibility of the substrate itself, without involving molding processes. It is understood that appropriate substrate materials (Young's modulus), substrate thickness, bending radius, and external forces can be selected according to the required structure. For example, in this application of the light guide, the inner bending radius of the bending segment is greater than or equal to 2 mm. That is, for the bending segment of this multi-layered light guide, the inner bending radius R1 of the innermost first substrate 100a is greater than or equal to 2 mm (i.e., R1≥2mm), the inner bending radius R2 of the middle second substrate 100b is greater than or equal to the sum of 2 mm and the thickness T2 of the second substrate 100b (i.e., R2≥2mm+T2), and the inner bending radius R3 of the outermost third substrate 100c is greater than or equal to the sum of 2 mm and the thicknesses T2 and T3 of the second and third substrates 100c (i.e., R3≥2mm+T2+T3). Understandably, if installation clearance is taken into account, the inner radius of the bend needs to be increased by the thickness of the installation clearance.

[0051] For some single-curved (2.5D) or double-curved (3D) applications, the various molding processes mentioned above can be used, with dedicated molds and openings to provide assembly clearances and corresponding wall thickness compensation. For example, in this application of light guides, the inner radius of the curved section is greater than or equal to twice the thickness of the substrate having that inner radius. In other words, for the curved section of this multilayer light guide, the inner bending radius R1 of the innermost first substrate 100a is greater than or equal to twice the thickness T1 of the first substrate 100a (i.e., R1 ≥ 2T1), the inner bending radius R2 of the middle second substrate 100b is greater than or equal to the sum of twice the thickness T1 of the first substrate 100a and the thickness T2 of the second substrate 100b (i.e., R2 ≥ 2T1 + T2), and the inner bending radius R3 of the outermost third substrate 100c is greater than or equal to the sum of twice the thickness T1 of the first substrate 100a, the thickness T2 of the second substrate 100b, and the thickness T3 of the third substrate 100c (i.e., R3 ≥ 2T1 + T2 + T3). Similarly, it can be understood that, if the installation gap is considered, the inner bending radius needs to be increased by the thickness of the installation gap.

[0052] Figure 12 and Figure 13 An example of a complex hyperbolic light guide is schematically illustrated. Taking the illustrated product as an example, different preset patterns can be achieved on the substrate 100 by varying the density and / or depth of the optical microstructures 130. To accommodate the construction requirements, the substrate 100 includes multiple curved segments, each of which may have the same or different inner radii of curvature, for example, Ra = 1.3 mm, Rb = 1.8 mm, Rc = 1.3 mm, Rd = 1.9 mm, Re = 2.5 mm, Rf = 6.1 mm, Rg = 1.3 mm, Rg = 70 mm (… Figure 13 The right half of the structure is symmetrical to the left half. The thickness T of the substrate 100 is, for example, 0.6 mm. Therefore, the inner radius of each bend is greater than twice the thickness T of the substrate 100, so as to avoid affecting the light guiding characteristics of the substrate 100 due to the inner radius of the bend being too small.

[0053] However, if the optical microstructure area is not pre-treated (i.e., the support member 140 is provided), the optical microstructure 130 will be damaged after the substrate 100 is bent, and the light extraction efficiency will drop to 10% (or less) of that before bending or even fail completely. Therefore, by adopting the solution of this utility model, the optical microstructure area of ​​the light guide is pre-treated (filled with slurry, PVD, etc.), and at each bend (including inner bends, outer bends, etc.), the inner radius of the bend is greater than or equal to twice the thickness of the substrate 100. This ensures that the light guiding characteristics of the substrate 100 and the light extraction mechanism of the optical microstructure 130 can still be maintained after the substrate 100 is bent. In other words, the light extraction efficiency can be maintained, for example, at 40% (or more) of that before the support member 140 was provided and before bending, so that the observer can still clearly observe the preset pattern formed by the optical microstructure 130 through the light-emitting surface 120.

[0054] The technical content and features of this utility model have been disclosed above. However, it is understood that under the creative concept of this utility model, those skilled in the art can make various changes and improvements to the above-disclosed concept, but all of them fall within the protection scope of this utility model.

[0055] The above description of the embodiments is illustrative and not restrictive, and the scope of protection of this utility model is determined by the claims.

Claims

1. A light guide component, comprising a substrate (100), characterized in that, The substrate (100) has a curved structure and includes a bottom surface (110) and a light-emitting surface (120) opposite to each other. A plurality of optical microstructures (130) recessed from the bottom surface (110) are formed on the substrate (100). The plurality of optical microstructures (130) are arranged to form a predetermined pattern, such that light propagating within the substrate (100) changes its propagation direction after passing through the plurality of optical microstructures (130) and exits from the light-emitting surface (120) to present the predetermined pattern on the light-emitting surface (120). Furthermore, the light guide also includes a support member (140) disposed inside at least a portion of the optical microstructures (130) among the plurality of optical microstructures (130), the support member being configured to at least partially maintain the shape of the plurality of optical microstructures during the formation of the curved structure on the substrate.

2. The light guide component according to claim 1, characterized in that, The thickness of the substrate (100) is between 100 μm and 6000 μm, and / or, the maximum depth of each of the plurality of optical microstructures (130) recessed from the bottom surface (110) is between 5 μm and 20 μm.

3. The light guide component according to claim 1, characterized in that, Each of the plurality of optical microstructures (130) is configured to be hemispherical, crater-shaped, wedge-shaped, or pyramid-shaped.

4. The light guide component according to claim 1, characterized in that, The substrate (100) has a monobolic or hyperbolic structure.

5. The light guide component according to claim 1, characterized in that, The substrate (100) includes at least one curved segment (A1) with an inner radius (R) greater than or equal to twice the thickness (T) of the substrate (100).

6. The light guide element according to claim 5, characterized in that, The substrate (100) also includes at least one flat segment (A2) extending from the curved segment (A1), and the plurality of optical microstructures (130) are disposed on the curved segment (A1) and / or the flat segment (A2).

7. The light guide component according to claim 1, characterized in that, The support (140) is configured as a solid slurry housed inside the optical microstructure (130).

8. The light guide element according to claim 7, characterized in that, The paste is either nano-silver paste or nano-copper paste.

9. The light guide element according to claim 7, characterized in that, The volume of the slurry accounts for at least 30% of the volume of the corresponding optical microstructure (130).

10. The light guide component according to claim 1, characterized in that, The support (140) is a coating layer that at least partially covers the inner wall of the optical microstructure (130).

11. The light guide element according to claim 1, characterized in that, The material of the matrix (100) is polycarbonate, polymethyl methacrylate or thermoplastic polyurethane.

12. The light guide element according to claim 1, characterized in that, The light guide includes multiple substrates (100a, 100b, 100c), which are stacked and at least two substrates are provided with optical microstructures, and the optical microstructures on the at least two substrates form different preset patterns.

13. The light guide element according to claim 12, characterized in that, The two adjacent substrates fit together tightly.

14. The light guide element according to claim 13, characterized in that, The light guide includes at least one curved section, the inner radius of which is greater than or equal to 2 mm.

15. The light guide element according to claim 13, characterized in that, The light guide includes at least one curved section, the inner radius of which is greater than or equal to twice the thickness of the substrate having the inner radius of which is curved.

16. The light guide element according to claim 1, characterized in that, The light guide is a light guide plate or a flexible light guide film.

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