Light guide member

Abstract

A light guide member, comprising a base (100), and a bottom surface (110) and an emergent light surface (120) opposite to each other. A plurality of optical microstructures (130) recessed from the bottom surface (110) are formed on the base (100); the plurality of optical microstructures (130) form a preset pattern, such that the propagation direction of light propagated in the base (100) changes after the light passes through the plurality of optical microstructures (130), and then the light is emitted from the emergent light surface (120), so as to present the preset pattern on the emergent light surface (120); a support member (140) is provided inside at least part of the plurality of optical microstructures (130); and the support member (140) is configured to at least partially maintain the shapes of the plurality of optical microstructures (130) in the process of forming a curved configuration of the base (100).

Description

Light guide Technical Field

[0001] This disclosure relates to the field of light guide technology. More specifically, this disclosure relates to a light guide having a curved structure. Background Technology

[0002] Currently, some vehicle interior trim components (e.g., door panels, dashboards, headliners, etc.) are equipped with luminous decorative elements to display patterns on these trim components as needed. These luminous decorative elements include, for example, the light guide shown in Figure 1. The substrate 100' of the light guide includes a bottom surface 110 and a light-emitting surface 120 facing each other. On the bottom surface 110, multiple optical microstructures 130 are formed, for example, recessed from the bottom surface 110, through various processes (including but not limited to embossing, screen printing, pad printing, laser engraving, UV offset printing, etc.). These optical microstructures 130 collectively form a preset pattern, so that light propagating within the substrate 100' can change its propagation direction after passing through these optical microstructures 130 and be emitted from the light-emitting surface 120, thereby allowing the observer 200 to observe the preset pattern on the light-emitting surface 120. In other words, due to the presence of the optical microstructures 130, the total internal reflection mechanism in this area is disrupted, thus enabling light to be emitted through the light-emitting surface 120.

[0003] However, the main drawback of the aforementioned light guide is that, as shown in Figure 2, when the substrate 100' of the light guide is bent according to requirements through various molding processes or installation methods, the optical microstructure 130 on it will undergo significant deformation. For example, the optical microstructure 130 may become noticeably shallower or even disappear. This disrupts the light extraction mechanism in that area, making it difficult to maintain sufficient light extraction efficiency, and causing the observer to be unable to properly observe the preset pattern formed by the optical microstructure 130.

[0004] The purpose of this disclosure is to overcome at least one deficiency in the prior art. More specifically, the light guide according to this disclosure has a curved structure and can ensure the light extraction mechanism of the optical microstructure region, thereby ensuring the highest possible light extraction efficiency and enabling the observer to normally observe the preset pattern formed by the optical microstructure.

[0005] To this end, this disclosure provides a light guide, including a substrate having a curved structure and including a bottom surface and a light-emitting surface opposite to each other. A plurality of optical microstructures recessed from the bottom surface are formed on the substrate. The plurality of optical microstructures form a preset pattern, such that light propagating within the substrate changes its propagation direction after passing through the plurality of optical microstructures and is emitted from the light-emitting surface to present the preset pattern on the light-emitting surface. Furthermore, the light guide also includes a support member disposed within at least a portion of the plurality of optical microstructures, 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 of the substrate.

[0006] Based on the above-described technical concept, this disclosure may further include any one or more of the following alternative forms.

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

[0008] In some alternative forms, the shape of each of the plurality of optical microstructures is set as hemispherical, crater-shaped, wedge-shaped, or pyramid-shaped.

[0009] In some alternative forms, the matrix has a monobolic or hyperbolic structure.

[0010] In some alternative forms, the substrate includes at least one curved segment with an inner radius of curvature greater than or equal to twice the thickness of the substrate.

[0011] In some alternative forms, the substrate further includes at least one flat segment extending from the curved segment, wherein the plurality of optical microstructures are disposed on the curved segment and / or the flat segment.

[0012] In some alternative forms, the support is configured as a solid slurry housed within the optical microstructure.

[0013] In some alternative forms, the paste is a nano silver paste or a nano copper paste.

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

[0015] In some alternative forms, the support is a coating layer that at least partially covers the inner wall of the optical microstructure.

[0016] In some alternative forms, the matrix material is polycarbonate, polymethyl methacrylate, or thermoplastic polyurethane.

[0017] In some alternative forms, the light guide includes multiple substrates stacked together, with optical microstructures disposed on at least two substrates, and the optical microstructures on the at least two substrates forming different preset patterns.

[0018] In some alternative forms, two adjacent substrates are closely fitted together.

[0019] In some alternative forms, the light guide includes at least one curved section with an inner radius of curvature greater than or equal to 2 mm.

[0020] In some alternative forms, 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.

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

[0022] Compared to existing technologies, the light guide according to this disclosure has several beneficial technical effects, especially: by filling the optical microstructure of the substrate with a support member, the shape of the optical microstructure can be maintained at least partially after bending, thereby ensuring the light emission mechanism in that area and achieving the desired ideal light emission efficiency, allowing the observer to still normally observe the preset pattern formed by these optical microstructures through the light emission surface. Furthermore, this light guide has a simple structure, is easy to mold, and has a low cost, thus enabling its widespread application in various types of vehicle trim parts. Attached Figure Description

[0023] Other features and advantages of this disclosure will be better understood through the following detailed description of preferred embodiments in conjunction with the accompanying drawings. In the drawings, the same reference numerals denote the same or similar parts.

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

[0025] Figure 2 is a schematic diagram of the bending deformation of the light guide in Figure 1.

[0026] Figure 3 is a schematic diagram of various shapes of optical microstructures on a light guide.

[0027] Figure 4 is a schematic diagram of a light guide according to one embodiment of the present disclosure.

[0028] Figure 5 is a schematic diagram of the light guide in Figure 4 before bending deformation.

[0029] Figure 6 is a schematic diagram of two light guides with curved structures.

[0030] Figure 7 is a schematic diagram of two other light guides with curved structures.

[0031] Figure 8 is a schematic diagram of two bending deformation modes of the light guide in Figure 5.

[0032] Figure 9 is a schematic diagram of the deformation of the optical microstructure of the light guide in Figure 5.

[0033] Figure 10 is an enlarged view of the boxed area in Figure 9.

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

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

[0036] Figure 13 is a schematic diagram of a cross-section taken along plane AA in Figure 12.

[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 this disclosure, but also, where necessary, to limit this disclosure. 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 disclosure, and are not intended to limit the scope of this disclosure.

[0039] This disclosure 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 disclosure does not limit the application. Specifically, when the light guide is applied to vehicle trim, it typically needs to be manufactured with partial or overall bending to suit the trim's structure, installation environment, pattern effects, or other requirements. Bending a flat light guide can be achieved using simple fasteners during installation, or by employing 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] Preferred embodiments of the light guide of this disclosure will now be described with reference to the accompanying drawings.

[0041] As shown in Figures 3 to 5, the light guide according to this disclosure includes a substrate 100 having a curved structure formed by bending a flat piece, and including 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, 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 a generally flat plate-like or thin-film structure as shown in FIG. 5. The total internal reflection mechanism in this region is disrupted by the arrangement of the 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. As shown in FIG. 3, 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 limited; it can be a crater shape, wedge shape, hemispherical shape, or any other suitable shape, as schematically shown from left to right in Figure 3, or a pyramid shape (i.e., a triangular pyramid).

[0043] To accommodate the construction of vehicle trim components or the requirements of the installation environment and pattern effects, the light guide is bent into a configuration as shown in Figure 4. After bending, the bottom surface 110 where the optical microstructure 130 is formed is located on the inner side, i.e., with a smaller bending radius, while the opposing light-emitting surface 120 is located on the outer side, i.e., with a larger bending radius. The optical microstructure area is bent inwards. According to one embodiment, after bending, the bottom surface 110 where the optical microstructure 130 is formed may be located on the outer side, i.e., with a larger bending radius, while the opposing light-emitting surface 120 is located on the inner side, i.e., with a smaller bending radius. The optical microstructure area is bent outwards (see Figures 8 to 10, for example).

[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 disclosure, 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 by 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, the shape, curvature, area and other characteristics of these optical microstructures 130 can be maintained at least partially, 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] Figures 6 and 7 schematically illustrate several light guides with different bending structures. 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) during installation using simple fasteners or through processes such as high-pressure forming, vacuum forming, and hot bending. They can also be formed into a hyperbolic structure (i.e., a surface with non-zero Gaussian curvature, which has curvature in two principal directions, also known as a 3D structure) through processes such as high-pressure forming, vacuum forming, and hot bending. As shown in Figures 6 and 7, the substrate 100 of each light guide includes at least one bent 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 bent 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 components' 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 a restricted arrangement area for the optical microstructure, while the flat segment A2 is an ideal arrangement area for the optical microstructure. In principle, the optical microstructure can be located 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, within 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 disrupt 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 substrate 100 is bent following the filling of the slurry, without considering the attenuation caused by the slurry's own properties, the filling volume (i.e., coverage) of the slurry in the optical microstructure 130 has the greatest impact on the light extraction efficiency. As shown in Figure 8, ignoring the influence of the slurry's own properties on the light efficiency, bending the substrate 100 will cause deformation of the optical microstructure 130, resulting in light loss. However, the area filled with slurry will maintain its original light extraction efficiency, and the filling volume is directly proportional to the light extraction efficiency (relative brightness). That is, from left to right in Figure 8 (refer to 140a, 140b, 140c), the larger the volume of the filled slurry, the higher the light extraction efficiency. As shown in Figures 9 and 10, taking the outward bending of the optical microstructure region as an example, the actual filling region in the 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 ratio of the volume of the ideal filling region S to the total 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 slurry occupies at least 30% of the volume of the corresponding optical microstructure 130, more preferably at least 50%. Thus, in the region of the optical microstructure, due to the filling of the 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), which 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 disclosure can also be applied to multi-layer stacking. As shown in FIG11, 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, which 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 the 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. In addition, light can also be incident sequentially into each substrate in a cyclic or random manner, so that the light guide exhibits 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] Figures 12 and 13 schematically illustrate an example of a complex hyperbolic light guide. 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 with 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 (the right half of Figure 13 shows a structure symmetrical to the left half). The thickness T of the substrate 100 is, for example, 0.6 mm, and each of the aforementioned inner radii of curvature is thus greater than twice the thickness T of the substrate 100, avoiding the light guiding characteristics of the substrate 100 being affected by an excessively small inner radii of curvature.

[0053] However, if the optical microstructure region 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 disclosure, the optical microstructure region 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 at 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 disclosure have been disclosed above. However, it is understood that under the creative concept of this disclosure, 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 disclosure.

[0055] The above description of the embodiments is illustrative and not restrictive, and the scope of protection of this disclosure 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 the curved section.

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

Images