Optical member, light source module, and liquid crystal display device

Abstract

To provide an optical member capable of reducing irregularities in luminance when being disposed above a light source.SOLUTION: An optical member has multiple light control sections. The respective light control sections comprise an emission surface that serves as an upper surface, a first incident surface positioned below the emission surface, a second incident surface that is positioned in the outer periphery of the first incident surface in a top view and extends down from the first incident surface side, and a reflection surface that is positioned in the outer periphery of the second incident surface in a top view and is tilted in a direction separated from the center of the light control sections as it approaches the emission surface side from the second incident surface side. Light entering the first incident surface and the second incident surface and light reflected by the reflection surface are emitted from the emission surface. The first incident surface is a convex face curved in a direction separated from the emission surface. The emission surface is a convex face curved in a direction separated from the first incident surface. The radius of curvature of the first incident surface is larger than the radius of curvature of the emission surface in a cross-section view, and the emission surfaces of the adjacent light control sections are connected directly.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to an optical member, a light source module, and a liquid crystal display device. [Background technology]

[0002] A virtual image display device is disclosed that includes an illumination unit that emits illumination light, an image forming unit that forms an image by transmitting the illumination light and emits display light for the image, and a focusing unit that focuses the illumination light toward the image forming unit. The focusing unit focuses the illumination light from the illumination unit toward the image forming unit. The focusing unit is mainly composed of a lens array. The lens array is a TIR lens array. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-94052 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure aims to provide an optical member that can reduce brightness unevenness when placed above a light source, a light source module including the optical member, and a liquid crystal display device including the light source module. [Means for solving the problem]

[0005] An optical element according to one embodiment of the present disclosure has a plurality of light control sections, each of which comprises an exit surface serving as the upper surface, a first incident surface located below the exit surface, a second incident surface located on the outer periphery of the first incident surface in a top view and extending downward from the first incident surface side, and a reflecting surface located on the outer periphery of the second incident surface in a top view and inclined in a direction away from the center of the light control section as it approaches the exit surface side from the second incident surface side, wherein light incident on the first incident surface and the second incident surface, and light reflected by the reflecting surface, are emitted from the exit surface, wherein the first incident surface is a convex surface that curves away from the exit surface, and the exit surface is a convex surface that curves away from the first incident surface, and in a cross-sectional view, the radius of curvature of the first incident surface is greater than the radius of curvature of the exit surface, and the exit surfaces of adjacent light control sections are directly connected to each other.

[0006] An optical element according to one embodiment of the present disclosure has a plurality of light control sections, each of which comprises an exit surface serving as the upper surface, a first incident surface located below the exit surface, a second incident surface located on the outer periphery of the first incident surface in a top view and extending downward from the first incident surface side, and a reflecting surface located on the outer periphery of the second incident surface in a top view and inclined in a direction away from the center of the light control section as it approaches the exit surface side from the second incident surface side, wherein light incident on the first incident surface and the second incident surface, as well as light reflected by the reflecting surface, is emitted from the exit surface, the first incident surface is a flat surface, and the exit surface is a convex surface curved in a direction away from the first incident surface, and the exit surfaces of adjacent light control sections are directly connected to each other.

[0007] A light source module according to one embodiment of the present disclosure includes a surface light source having a substrate and a plurality of light sources arranged on the substrate, and an optical element according to one embodiment of the present disclosure arranged above the light sources.

[0008] A liquid crystal display device according to an embodiment of the present disclosure includes a light source module according to an embodiment of the present disclosure. [Effects of the Invention]

[0009] According to an embodiment of the present disclosure, it is possible to provide an optical member that can reduce brightness unevenness when disposed above a light source, a light source module including the optical member, and a liquid crystal display device including the light source module. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 2 is a schematic perspective view illustrating the optical member according to the first embodiment. [Figure 2] 1A and 1B are schematic top views illustrating an optical member according to a first embodiment. [Figure 3] FIG. 2 is a schematic bottom view illustrating the optical member according to the first embodiment. [Figure 4] 4 is a schematic cross-sectional view taken along line IV-IV in FIG. 2, illustrating the optical member according to the first embodiment. [Figure 5] 10 shows the results of a simulation of the optical path of light incident on the light control unit. [Figure 6] 3A and 3B are diagrams illustrating the inclination of a reflecting surface in the optical member according to the first embodiment. [Figure 7] FIG. 10 is a diagram (part 1) illustrating the cross-sectional shape of a light control section when the exit surface is rectangular. [Figure 8] FIG. 8 is a perspective view of the light control unit shown in FIG. [Figure 9] FIG. 10 is a diagram (part 2) illustrating the cross-sectional shape of the light control section when the exit surface is rectangular. [Figure 10] FIG. 10 is a perspective view of the light control unit shown in FIG. [Figure 11] FIG. 2 is a schematic cross-sectional view illustrating an optical member according to a first modified example of the first embodiment. [Figure 12] FIG. 2 is a schematic top view illustrating a surface light source. [Figure 13] 1 is a schematic top view illustrating a light source module including a surface light source and an optical member; [Figure 14] 14 is a schematic cross-sectional view taken along line XIV-XIV in FIG. 13, illustrating a light source module including a surface light source and an optical member. [Figure 15] 3 is a schematic cross-sectional view illustrating a light source mounted in a surface light source. FIG. [Figure 16] FIG. 10 is a schematic partial cross-sectional view (part 1) showing another example of the light source module. [Figure 17] FIG. 10 is a schematic partial cross-sectional view (part 2) showing another example of the light source module. [Figure 18] 1 is a partial cross-sectional view illustrating a liquid crystal display device having a light source module. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, a description will be given of an embodiment of the invention with reference to the drawings. In the following description, terms indicating specific directions or positions (e.g., "upper," "lower," and other terms including these terms) will be used as necessary. However, the use of these terms is intended to facilitate understanding of the invention with reference to the drawings, and the meaning of these terms does not limit the technical scope of the present invention. Furthermore, parts that appear with the same reference numerals in multiple drawings indicate the same or equivalent parts or components.

[0012] Furthermore, in this disclosure, polygons such as triangles and quadrilaterals are referred to as polygons, including shapes in which the corners of the polygons have been processed, such as by rounding, chamfering, corner removal, or rounding. Shapes in which processing has been applied not only to the corners (edges of the sides) but also to the middle portions of the sides are also referred to as polygons. In other words, shapes in which partial processing has been applied while retaining the polygon as a base are included in the interpretation of "polygon" described in this disclosure.

[0013] The same applies to words that represent specific shapes, such as trapezoids, circles, and irregularities, not just polygons. The same also applies when dealing with the sides that form the shape. In other words, even if the corners or middle part of a side have been processed, the interpretation of "side" includes the processed part. Note that when distinguishing a "polygon" or "side" that has no processing from a processed shape, the word "strict" is added, for example, "strict quadrangle."

[0014] Furthermore, the embodiments shown below are intended to exemplify optical components and the like embodying the technical concepts of the present invention, and are not intended to limit the scope of the present invention. Furthermore, unless otherwise specified, the dimensions, materials, shapes, relative positions, and the like of the components described below are intended for illustrative purposes only and are not intended to limit the scope of the present invention. Furthermore, the content described in one embodiment may also be applied to other embodiments and modified examples. Furthermore, the sizes and positional relationships of components shown in the drawings may be exaggerated for clarity. Furthermore, to avoid overly complex drawings, schematic diagrams may be used in which some elements are omitted, or end views may be used as cross-sectional views showing only the cut surface.

[0015] First Embodiment (Optical component 1) Fig. 1 is a schematic perspective view illustrating an optical member according to a first embodiment. Fig. 2 is a schematic top view illustrating an optical member according to the first embodiment. Fig. 3 is a schematic bottom view illustrating an optical member according to the first embodiment. Fig. 4 is a schematic cross-sectional view taken along line IV-IV in Fig. 2, illustrating the optical member according to the first embodiment. For reference, Figs. 1 to 4 show an X-axis, a Y-axis, and a Z-axis that are orthogonal to each other.

[0016] As shown in FIGS. 1 to 4, the optical member 1 has a plurality of light control units 10. In the examples of FIGS. 1 to 4, the light control units 10 are arranged two-dimensionally in a matrix of 5 rows and 9 columns. The X-axis direction is the row direction, and the Y-axis direction is the column direction. In other words, the light control units 10 are arranged so that their centers are located at the centers of square lattice points. The light control units 10 are arranged, for example, at a constant pitch in the X-axis and Y-axis directions. The arrangement of the light control units 10 is not limited to the examples of FIGS. 1 to 4. For example, the light control units 10 may be arranged so that their centers are located at the centers of hexagonal lattice points.

[0017] Each light control unit 10 is configured with a TIR (Total Internal Reflection) lens. Each light control unit 10 is, for example, quadrangular when viewed from above. Each light control unit 10 may be square or rectangular when viewed from above. Note that top view refers to viewing the object from the Z axis + direction to the Z axis - direction.

[0018] Each light control unit 10 includes an exit surface 11 serving as the top surface, a first incident surface 12 located below the exit surface 11, a second incident surface 13 located on the outer periphery of the first incident surface 12 in a top view and extending downward from the first incident surface 12 side, and a reflecting surface 14 located on the outer periphery of the second incident surface 13 in a top view and inclined in a direction away from the center of the light control unit 10 as it approaches the exit surface 11 from the second incident surface 13 side. Light incident on the first incident surface 12 and the second incident surface 13, and light reflected by the reflecting surface 14, are emitted from the exit surface 11.

[0019] The exit surface 11 is a convex surface that curves in a direction away from the first entrance surface 12. In other words, the exit surface 11 is arc-shaped in a cross-sectional view. When viewed from above, the exit surface 11 is, for example, quadrangular. When viewed from above, the exit surface 11 may be square or rectangular. In the example of FIGS. 1 to 4, the exit surface 11 is square when viewed from above. When viewed from above, the length of one side of the exit surface 11 is, for example, 1 mm or more and 20 mm or less. The exit surfaces 11 of adjacent light control units 10 are directly connected to each other. In other words, there is no flat surface or the like between the exit surfaces 11 of adjacent light control units 10.

[0020] The first incident surface 12 is a convex surface that curves in a direction away from the exit surface 11. When viewed from above, the first incident surface 12 is, for example, quadrangular. When viewed from above, the first incident surface 12 may be square or rectangular. When viewed from above, the first incident surface 12 may be circular. Note that the term "circular" here includes a perfect circle, an ellipse, and a shape that forms a ring that is symmetrical in both the left and right and top and bottom directions.

[0021] 1 to 4, first incident surface 12 is square in top view. In top view, first incident surface 12 is smaller than exit surface 11. In top view, first incident surface 12 overlaps with exit surface 11. In cross-sectional view, the radius of curvature of first incident surface 12 is larger than the radius of curvature of exit surface 11. Note that the cross section here refers to a vertical cross section cut along the Z direction.

[0022] The second incident surface 13 is inclined in a direction approaching the center of the light control unit 10 as it approaches the first incident surface 12. For example, when the optical member 1 is placed on a horizontal surface with the first incident surface 12 side facing downwards, the second incident surface 13 is a plane inclined with respect to the horizontal plane. In this case, the angle between the horizontal plane and the second incident surface 13 can be, for example, 80 degrees or more and less than 90 degrees. The second incident surface 13 has a rectangular frame shape when viewed from above. The horizontal plane is a plane parallel to a plane including the X-axis and the Y-axis.

[0023] For example, when the optical member 1 is placed on a horizontal surface with the first incident surface 12 side facing downwards, the reflecting surface 14 is a plane that is inclined with respect to the horizontal plane. In this case, the angle between the horizontal plane and the reflecting surface 14 can be, for example, 40 degrees or more and 70 degrees or less. The reflecting surface 14 has a rectangular frame shape when viewed from above.

[0024] 1 to 4, each light control unit 10 further includes a connection surface 15 that connects the first incident surface 12 and the second incident surface 13. The connection surface 15 has a rectangular frame shape when viewed from above. For example, the connection surface 15 is a plane that is parallel to the horizontal plane when the optical member 1 is placed on the horizontal plane with the first incident surface 12 side facing downwards. Note that each light control unit 10 may not include the connection surface 15, and the first incident surface 12 and the second incident surface 13 may be directly connected.

[0025] In Fig. 4, line A is a line connecting the center of first incident surface 12 and the center of exit surface 11 in top view, and is the optical axis of light control unit 10. Line A is parallel to the Z axis. That is, in the example of Fig. 4, the center of first incident surface 12 coincides with the center of exit surface 11 in top view. Note that "the centers coincide in top view" refers to a case where the distance between the centers of the objects to be compared is 0.1 mm or less in top view.

[0026] 1 to 4, the optical member 1 further has a frame portion 20 that surrounds the outside of the multiple light control portions 10 in a top view. The frame portion 20 is provided between the first incident surface 12 and the exit surface 11 of the light control portions 10 in the Z-axis direction. The upper surface of the frame portion 20 is, for example, on the same plane as the position where the exit surfaces 11 of adjacent light control portions 10 are connected to each other. Note that the optical member 1 does not necessarily have to have the frame portion 20.

[0027] The light control units 10 can be made of a material such as polycarbonate resin, acrylic resin, cycloolefin polymer (COP), or silicone resin. The pitch of the light control units 10 can be, for example, 1 mm or more and 20 mm or less. Here, the pitch refers to the distance between the centers of two adjacent light control units 10. The light control units 10 can be made, for example, by molding. When the optical member 1 has a frame unit 20, the frame unit 20 can be made integrally with the light control units 10 using the same material, for example.

[0028] As described above, each light control unit 10 in the optical member 1 is configured with a TIR lens. This makes it possible to improve the brightness of the light emitted from the optical member 1 when the optical member 1 is used in combination with a light source and the light control unit 10 is disposed above the light source (for example, see FIG. 14 described later).

[0029] Furthermore, in each light control unit 10 of the optical element 1, the first incident surface 12 is a convex surface that curves in a direction away from the exit surface 11, and the exit surface 11 is a convex surface that curves in a direction away from the first incident surface 12. The radius of curvature of the first incident surface 12 is larger than the radius of curvature of the exit surface 11, and the exit surfaces 11 of adjacent light control units 10 are directly connected to each other. This improves the uniformity of the light emitted from the optical element 1 when the optical element 1 is used in combination with a light source and the light control unit 10 is disposed above the light source. Improving the uniformity of light is essentially synonymous with reducing brightness unevenness. Hereinafter, the reduction of brightness unevenness will be described in detail.

[0030] Fig. 5 shows the results of a simulation of the optical path of light incident on the light control unit. Fig. 5 shows a case where the light control unit 10X is used as Comparative Example 1, a case where the light control unit 10Y is used as Comparative Example 2, a case where the light control unit 10A is used as Example 1, and a case where the light control unit 10B is used as Example 2.

[0031] The shapes of the exit surfaces of the light control unit 10X, the light control unit 10Y, and the light control units 10A and 10B are different. The exit surface of the light control unit 10X is composed of only a flat surface. The exit surface of the light control unit 10Y is composed of a convex surface and flat surfaces located around the convex surface in a top view. The exit surfaces of the light control units 10A and 10B are composed of only a convex surface, similar to the light control unit 10 described above. Furthermore, the first entrance surfaces 12 of the light control units 10X, 10Y, and 10A are circular in a top view. In contrast, the first entrance surface 12 of the light control unit 10B is rectangular in a top view, similar to the light control unit 10 described above.

[0032] In Fig. 5, light with a Lambertian distribution enters each light control unit from a light source 520 arranged on a substrate 510, travels along an optical path as indicated by the arrow, and is emitted from the exit surface. The thickness of the arrows in Fig. 5 schematically indicates the intensity of the light. In addition to the configuration of each light control unit, Fig. 5 also shows the luminance distribution on the exit surface and the shape and uniformity of first entrance surface 12. Here, uniformity refers to the ratio of the lowest luminance to the highest luminance in the luminance distribution, and the higher this value, the better the uniformity.

[0033] The light control unit 10X according to Comparative Example 1 is capable of totally reflecting light traveling from the light source 520 in an obliquely upward direction close to a horizontal direction at the reflecting surface and extracting it from the exit surface. However, the brightness of the light totally reflected at the reflecting surface is smaller than the brightness of light that is emitted from the exit surface without reaching the reflecting surface, so the brightness in region D drops significantly and becomes dark. As a result, the brightness of the light emitted from the exit surface varies greatly, with a uniformity of 48%. Furthermore, the difference in brightness between region D and the region inside it is large, resulting in a discontinuous brightness distribution at the boundary between region D and the region inside it.

[0034] The light control unit 10Y according to Comparative Example 2 has a smaller curvature of the first incident surface 12 than the light control unit 10X, and a portion of the exit surface is convex. This configuration increases the spread of light incident from the first incident surface 12 within the light control unit 10Y, improving the luminance distribution compared to Comparative Example 1. However, the luminance in region D is not sufficiently improved. As a result, the luminance unevenness of the light exiting the exit surface is somewhat large, with a uniformity of 58%. Although this is an improvement over Comparative Example 1, the luminance difference between region D and the region inside it remains large, resulting in a discontinuous luminance distribution at the boundary between region D and the region inside it. It is possible to improve the uniformity of Comparative Example 2 by imparting a light diffusion effect to the convex surface of the exit surface to reduce the luminance at the convex surface. However, this is not a preferable method because it does not provide sufficient effects and reduces the exit efficiency.

[0035] In the light control unit 10A according to Example 1, the luminance distribution was improved and the uniformity was 62% compared to Comparative Examples 1 and 2. The reason for this is as follows.

[0036] First, in the light control unit 10A, the degree of light concentration on the incident side is reduced by increasing the radius of curvature of the first incident surface 12, and the light can be spread inside the light control unit 10A. This reduces the amount of light that is concentrated near the center of the exit surface, and the light can be dispersed over the entire exit surface. Then, by adjusting the radius of curvature on the exit surface, the dispersed light is concentrated on the exit surface. As a result, it is possible to prevent only the center of the exit surface from becoming bright, and improve uniformity.

[0037] Next, in the light control unit 10A, the entire exit surface is made convex, which makes it easier to collect light and improves uniformity. Furthermore, since the exit surface does not include a flat surface as in Comparative Examples 1 and 2, discontinuous brightness distribution is less likely to occur, and brightness unevenness can be reduced.

[0038] The light control unit 10B according to Example 2 exhibited a further improved luminance distribution compared to the light control unit 10A according to Example 1, with a uniformity of 65%. This is because the rectangular shape of the first incident surface 12 in top view allows light to more easily reach the vicinity of the contact points between the corners of adjacent light control units 10B in top view, compared to when the circular shape of the first incident surface 12 in top view is used. Thus, the rectangular shape of the first incident surface 12 in top view can further reduce luminance unevenness compared to when the circular shape of the first incident surface 12 in top view is used. Furthermore, by providing a textured finish on the exit surface, i.e., by forming fine irregularities on the exit surface, light is diffused as it passes through the exit surface, resulting in even greater uniformity than in Example 2.

[0039] FIG. 6 is a diagram illustrating the inclination of the reflecting surface in the optical member according to the first embodiment. In FIG. 6, (1) shows half of the first cross section of the light control unit, and (2) and (3) show half of the second cross section. Here, the first cross section is a vertical cross section passing through the center of the light output surface 11 and cut parallel to one side of the light output surface 11. For example, when the light output surface 11 is a rectangle in top view, the direction in which one of two orthogonal sides of the rectangle extends is the X-axis direction, the direction in which the other extends is the Y-axis direction, and the direction perpendicular to the X-axis and Y-axis directions is the Z-axis direction. In this case, the first cross section is a cross section cut along a plane passing through the center of the light output surface 11 and parallel to the XZ plane (0-degree cross section), or a cross section cut along a plane parallel to the YZ plane (90-degree cross section). For example, when the light output surface 11 is a square in top view, the 0-degree cross section and the 90-degree cross section coincide with each other. The second cross section is a vertical cross section cut along a diagonal of the light output surface 11. When the emission surface 11 is square in top view, the second cross section is a 45-degree cross section that is inclined at 45 degrees with respect to the 0-degree cross section and the 90-degree cross section in top view.

[0040] 6(1) to 6(3), the shape of the first incident surface 12 is a square. In addition, in FIG. 6(1) to 6(3), the line O is the center line of the light control portion. That is, the line O is a line that passes through the center of the exit surface 11 and is parallel to the Z-axis direction. In the first cross section shown in (1), the angle θ between the center line of the light control portion and the reflecting surface 14 is 33 degrees. In other words, the angle of the reflecting surface 14 with respect to the horizontal plane is 57 degrees. In this case, the light reflected by the reflecting surface 14 reaches near the outermost periphery of the exit surface 11 in the 0-degree and 90-degree directions, and the area near the outermost periphery of the exit surface 11 does not become dark in these directions.

[0041] In contrast, when the angle θ is set to the same value as in the first cross section shown in (1), as in the second cross section shown in (2), the light reflected by the reflecting surface 14 does not reach the vicinity of the outermost periphery of the light exit surface 11 in the 45-degree direction. As a result, the vicinity of region D located on the outermost periphery of the light exit surface 11 in the 45-degree direction is darker than in the 0-degree and 90-degree directions, resulting in uneven brightness.

[0042] Therefore, it is preferable to change the value of angle θ between the first cross section and the second cross section. Specifically, it is preferable to make angle θ larger, as in the second cross section shown in (3), than in the first cross section shown in (1). In the second cross section shown in (3), angle θ is 40 degrees. In other words, the angle of reflecting surface 14 with respect to the horizontal plane is 50 degrees. As a result, light reflected by reflecting surface 14 reaches the outermost periphery of exit surface 11 even in the 45-degree direction, so that the outermost periphery of exit surface 11 is not darkened even in this direction. As a result, the uniformity of brightness near the outermost periphery of exit surface 11 is improved in the 0-degree, 90-degree, and 45-degree directions, thereby reducing brightness unevenness of light emitted from exit surface 11.

[0043] FIG. 7 is a diagram (part 1) for explaining the cross-sectional shape of a light control unit when the exit surface is rectangular. In FIG. 7, the upper right is a top view. The upper left is a vertical cross section (for convenience, referred to as the third cross section) taken through the center of the rectangular exit surface 11 and parallel to the short side. The lower right is a vertical cross section (for convenience, referred to as the fourth cross section) taken through the center of the rectangular exit surface 11 and parallel to the long side. FIG. 8 is a perspective view of the light control unit shown in FIG. 7.

[0044] 7 and 8, in top view, the exit surface 11 is a rectangle with short and long sides. The radius of curvature of the exit surface 11 is the same in the third cross section and the fourth cross section. The height from the lower end of the second entrance surface 13 of the portion where the exit surfaces 11 of adjacent light control units 10 contact each other is H2 in the fourth cross section, which is lower than H1 in the third cross section.

[0045] 7 and 8, the shapes of the light control units 10 are the same between the third cross section and the fourth cross section, and the spacing between the light control units 10 in the fourth cross section is wider than the spacing between the light control units 10 in the third cross section. Even when the exit surface 11 is rectangular, by making it have the shapes shown in Figures 7 and 8, the uniformity of the light emitted from the optical member can be improved and brightness unevenness can be reduced, just like when the exit surface 11 is square.

[0046] FIG. 9 is a diagram (part 2) for explaining the cross-sectional shape of the light control unit when the exit surface is rectangular. In FIG. 9, the upper right is a top view. The upper left is a vertical cross section (for convenience, referred to as the third cross section) taken through the center of the rectangular exit surface 11 and parallel to the short side. The lower right is a vertical cross section (for convenience, referred to as the fourth cross section) taken through the center of the rectangular exit surface 11 and parallel to the long side. FIG. 10 is a perspective view of the light control unit shown in FIG. 9.

[0047] 9 and 10, in top view, the exit surface 11 is a rectangle with short and long sides. The radius of curvature of the exit surface 11 is larger in the fourth cross section than in the third cross section. The height H1 from the lower end of the second entrance surface 13 at the portion where the exit surfaces 11 of adjacent light control units 10 meet is the same in the third cross section and the fourth cross section.

[0048] 9 and 10, the shape of the light control unit 10 is different between the third cross section and the fourth cross section. This shape is effective when the aspect ratio of the long side to the short side of the exit surface 11 becomes large and cannot be addressed by simply widening the spacing between the light control units 10 as in Figures 7 and 8. Even when the exit surface 11 is rectangular, by using the shapes shown in Figures 9 and 10, the uniformity of the light emitted from the optical member can be improved and brightness unevenness can be reduced, just like when the exit surface 11 is square.

[0049] 9 and 10, the inclination angle of the reflecting surface 14 in the fourth cross section may be made gentler than the inclination angle of the reflecting surface 14 in the third cross section, if necessary.

[0050] (Modification of Optical Member) 11 is a schematic cross-sectional view illustrating an optical member according to Modification 1 of the first embodiment. As shown in Fig. 11, optical member 1A differs from optical member 1, in which first incident surface 12 is a convex surface, in that first incident surface 12A in each light control unit 10 is a flat surface. First incident surface 12A is a plane that is parallel to the horizontal plane when optical member 1A is placed on a horizontal plane with first incident surface 12A side facing downwards.

[0051] In this way, the first incident surface 12A may be a flat surface. In this case, as in the case where the radius of curvature of the first incident surface 12 in the optical member 1 is increased, the degree of light concentration on the incident side can be reduced and the light can be spread inside the light control unit 10. This allows the optical member 1A to achieve the same effect as the optical member 1.

[0052] (light source module 300) Here, a light source module including a surface light source and an optical member will be described. First, the surface light source will be described. Fig. 12 is a schematic top view illustrating an example of a surface light source. The surface light source 200 shown in Fig. 12 includes a substrate 210 and a plurality of light sources 280 arranged on the substrate 210. The plurality of light sources 280 are arranged, for example, two-dimensionally in a matrix on the substrate 210.

[0053] Fig. 13 is a schematic top view illustrating a light source module including a surface light source and an optical member. Fig. 14 is a schematic cross-sectional view taken along line XIV-XIV in Fig. 13 illustrating a light source module including a surface light source and an optical member.

[0054] 13 and 14, the light source module 300 includes a surface light source 200 and an optical member 1 disposed above a light source 280 of the surface light source 200. The surface light source 200 and the optical member 1 are held in a housing so as to have a predetermined positional relationship, for example.

[0055] 13 and 14, in the light source module 300, the number of light sources 280 is equal to the number of light control units 10. In a top view, each light source 280 overlaps with the first incident surface 12 of the light control unit 10 located above the light source 280. Note that, when viewed from above, the light source 280 overlaps with the first incident surface 12 of the light control unit 10 means that, when viewed from above, the light emitting surface of the light source 280 overlaps with the first incident surface 12 of the light control unit 10. In addition, when viewed from above, it is preferable that the center of the light source 280 coincides with the center of the first incident surface 12. Note that, when the light emitting center of the light source 280 (the point on the light emitting surface where the luminance is highest) is deviated from the geometric center of the light source 280, it is preferable that the light emitting center of the light source 280 coincides with the center of the first incident surface 12, not the geometric center.

[0056] 14, pitch P1 is the distance in the X-axis direction connecting the centers of two adjacent light sources 280 in top view. Pitch P2 is the distance in the X-axis direction connecting the centers of two adjacent light control units 10 in top view. In the X-axis direction of the light source module 300, pitch P1 of the light sources 280 is preferably equal to pitch P2 of the light control units 10. Furthermore, in the Y-axis direction of the light source module 300, pitch of the light sources 280 is preferably equal to pitch of the light control units 10. This makes it easier for the entire light emitted from the light source 280 to be irradiated onto the first incident surface 12 and the second incident surface 13, thereby improving light utilization efficiency.

[0057] In the light source module 300, the number of light sources 280 may be less than the number of light control units 10. For example, the light source 280 may be a light source having a light-emitting surface divided into a plurality of regions. In this case, too, the light source 280 overlaps with the first incident surface 12 of the light control unit 10 in a top view. That is, the light-emitting surface of each light source 280 overlaps with the first incident surface 12 of the light control unit 10 in a top view.

[0058] In the light source module 300, light emitted from the light source 280 travels vertically and diagonally upward from the light source 280 and is incident on the first incident surface 12 and the second incident surface 13 of the light control unit 10 located above the light source 280. The light incident on the first incident surface 12 is collected by the light control unit 10 and emitted from the emission surface 11 to the outside of the light source module 300. The light incident on the second incident surface 13 is reflected by the reflecting surface 14 and emitted from the emission surface 11 to the outside of the light source module 300.

[0059] Here, the members included in the surface light source 200 will be described in detail.

[0060] (Substrate 210) The substrate 210 is a member for mounting a plurality of light sources 280. On the upper surface of the substrate 210, conductor wiring for supplying power to the light sources 280 is arranged.

[0061] Examples of the base material of the substrate 210 include ceramics, resin, composite materials, etc. Examples of resin include phenolic resin, epoxy resin, polyimide resin, BT resin, polyphthalamide (PPA), polyethylene terephthalate (PET), etc. Examples of composite materials include the above-mentioned resins mixed with glass fiber, silicon oxide, titanium oxide, aluminum oxide, etc., and metal substrates in which a metal member is coated with an insulating layer.

[0062] The thickness of the substrate 210 can be selected appropriately. The substrate 210 may be either a flexible substrate that can be manufactured by a roll-to-roll method or a rigid substrate. The rigid substrate may be a thin rigid substrate that can be bent.

[0063] Preferably, a light-reflecting member 220 is provided on the upper surface of the substrate 210 around the light source 280. The light-reflecting member 220 is preferably made of an insulating material. For example, the material of the light-reflecting member 220 may be at least one of a resin exemplified as the material of the substrate 210 mixed with a filler such as barium titanate, titanium oxide, aluminum oxide, silicon oxide, or zinc oxide, or a resin exemplified as the material of the substrate 210 containing a plurality of fine bubbles.

[0064] By providing the light reflective member 220 on the upper surface of the substrate 210, when the light source module 300 is configured with the surface light source 200 and the optical member 1, light emitted upward from the light source 280 and reflected downward by the optical member 1 is reflected upward again by the light reflective member 220 and enters the optical member 1. As a result, the light extraction efficiency of the light source module 300 can be improved.

[0065] (Light source 280) 15 is a schematic cross-sectional view illustrating a light source mounted in a surface light source. The light source 280 is, for example, rectangular in top view, but may be circular or the like. The top surface of the light source 280 is a light-emitting surface.

[0066] 15, light source 280 is a light emitting device including leads, a resin molded body, and a light emitting element. In the light emitting device, for example, a pair of plate-shaped leads 281 are partially embedded in resin molded body 283. Resin molded body 283 and the pair of leads 281 form a support body, and the support body has a recess defined by a bottom surface and side surfaces. The bottom surface defining the recess is formed by resin molded body 283 and a portion of the pair of leads 281, and the side surfaces have reflective surfaces with a predetermined inclination angle.

[0067] The space between the pair of leads 281 is filled with a resin molding 283, which constitutes part of the bottom surface that defines the recess. The resin molding 283 is, for example, rectangular in top view. Parts of the pair of leads 281 are exposed on the bottom surface of the resin molding 283 as external terminals. In the light emitting device, a light emitting element 282 may be placed in the recess, and the light emitting element 282 may be covered with a sealing member 285.

[0068] The base material constituting the lead 281 may be, for example, a plate-like body containing at least one metal selected from copper, aluminum, gold, silver, tungsten, iron, and nickel, or an alloy or clad material such as an iron-nickel alloy or phosphor bronze. A film (e.g., a plated film) containing silver, aluminum, gold, or an alloy thereof may be formed on the surface of the lead 281 in order to efficiently extract light from the light-emitting element 282. The metal film formed on the surface of the lead 281 may be a single-layer film or a multi-layer film.

[0069] The resin molded body 283 can be made of a resin containing a thermosetting resin or a thermoplastic resin. In particular, it is preferable to use a thermosetting resin. The thermosetting resin is preferably a resin with lower gas permeability than the resin used for the sealing member 285, and specific examples of the thermosetting resin include epoxy resin, silicone resin, modified epoxy resin such as silicone-modified epoxy resin, modified silicone resin such as epoxy-modified silicone resin, polyimide resin, modified polyimide resin, urethane resin, and modified urethane resin. The resin molded body 283 may contain glass fiber, titanium oxide, aluminum oxide, silicon oxide, etc.

[0070] The light emitting element 282 is placed on, for example, the bottom surface that defines the recess. The light emitting element 282 is fixed to the lead 281 by, for example, a bonding member. The light emitting element 282 has a pair of positive and negative electrodes, which are electrically connected to the pair of leads 281 via wires, respectively. Power can be supplied from an external source via the pair of leads 281 to cause the light source 280 to emit light.

[0071] The light-emitting element 282 is preferably, for example, a light-emitting diode. The light-emitting element 282 can be selected from those with any wavelength. The light-emitting element 282 emits, for example, blue, green, or red light. The light-emitting element 282 has a semiconductor stack. The semiconductor stack includes an n-type semiconductor layer, a p-type semiconductor layer, and a light-emitting layer sandwiched between them. The light-emitting layer may have a structure such as a double heterojunction or a single quantum well (SQW), or a structure with a group of active layers such as a multiple quantum well (MQW). The semiconductor stack may include multiple light-emitting layers. For example, the semiconductor stack may have a structure including two or more light-emitting layers between an n-type semiconductor layer and a p-type semiconductor layer, or may have a structure in which a structure including an n-type semiconductor layer, a light-emitting layer, and a p-type semiconductor layer in that order is repeated multiple times. When the semiconductor stack includes multiple light-emitting layers, the emission peak wavelengths may differ among the multiple light-emitting layers, or the semiconductor stack may include light-emitting layers with the same emission peak wavelength. The light emitting element 282 can be made of a nitride semiconductor such as GaN, InGaN, AlGaN, or AlInGaN. Furthermore, the red light emitting element can be made of GaAlAs, AlInGaP, or the like. Furthermore, semiconductor light emitting elements made of other materials may also be used. The composition, light emitting color, size, number, and other factors of the light emitting elements used can be appropriately selected depending on the purpose.

[0072] The light emitting element 282 is covered with a light-transmitting sealing member 285. A resin having excellent heat resistance, weather resistance, and light resistance is preferably used as the sealing member 285. Examples of such resins include silicone resin, modified silicone resin, epoxy resin, modified epoxy resin, urea resin, phenol resin, acrylic resin, urethane resin, or fluororesin, or a resin containing two or more of these resins.

[0073] To provide a predetermined function, the sealing member 285 can be mixed with at least one selected from the group consisting of fillers, pigments, and phosphors. Suitable fillers include barium titanate, titanium oxide, aluminum oxide, silicon oxide, and zinc oxide. The sealing member 285 may also contain organic or inorganic coloring dyes or coloring pigments to transmit light in a desired wavelength range. Furthermore, the sealing member 285 may also contain a phosphor.

[0074] When the sealing member 285 contains a phosphor, it functions as a wavelength conversion member. The wavelength conversion member absorbs at least a portion of the light emitted from the light emitting element 282 and emits light of a wavelength different from the wavelength of the light from the light emitting element 282. For example, the wavelength conversion member converts the wavelength of a portion of the blue light from the light emitting element 282 to emit yellow light. With this configuration, white light is obtained by mixing the blue light that has passed through the wavelength conversion member with the yellow light emitted from the wavelength conversion member.

[0075] The light source 280 may be a light-emitting element 282 instead of the light-emitting device shown in FIG. 15 . Here, the light-emitting element 282 may have a light-reflecting film on its upper surface. The light-reflecting film may be, for example, a metal film such as silver or aluminum, a dielectric multilayer film, a resin containing a filler such as barium titanate, titanium oxide, aluminum oxide, silicon oxide, or zinc oxide, or a combination thereof. A light-transmitting sealing member covering the light-emitting element 282 may be provided on the upper surface of the substrate 210. Examples of materials for the sealing member include light-transmitting resins such as epoxy resin, silicone resin, or a mixture thereof, glass, etc. Among these, silicone resin is preferred in view of its light resistance and ease of molding. The sealing member may contain a diffusing agent for diffusing light from the light-emitting element 282, a coloring agent corresponding to the color of light emitted by the light-emitting element 282, etc. The diffusing agent, coloring agent, etc. may be those known in the art.

[0076] (Another example of a light source module) Here, another example of a light source module including a surface light source and an optical member will be described. The light source module may include a diffusion sheet. Furthermore, the light source module may include a prism sheet when bending the optical axis. Furthermore, the light source module may include both a diffusion sheet and a prism sheet. Specific examples are shown below.

[0077] Fig. 16 is a schematic partial cross-sectional view (part 1) showing another example of a light source module. A light source module 300A shown in Fig. 16 includes a diffusion sheet 310 and a prism sheet 320 above an optical member 1 in this order.

[0078] By including diffusion sheet 310, light source module 300A can improve the uniformity of light extracted from light source module 300A to the outside. Furthermore, by including prism sheet 320, light source module 300A can change the optical axis of light extracted from light source module 300A to a predetermined direction. Note that the positional relationship between diffusion sheet 310 and prism sheet 320 may be upside down compared to that in FIG. 16 .

[0079] Fig. 17 is a schematic partial cross-sectional view (part 2) showing another example of a light source module. Light source module 300B shown in Fig. 17 differs from light source module 300A shown in Fig. 16 in that it does not include prism sheet 320. Light source module 300B shown in Fig. 17 also differs from light source module 300A shown in Fig. 16 in that it includes planar light source 200A instead of planar light source 200.

[0080] In the surface light source 200A, the optical axis of each optical member 1 and the optical axis of each light source 280 are shifted in the X-axis direction. This allows the optical axis of light extracted from the light source module 300B to be changed to a predetermined direction even without a prism sheet. Note that the optical axis of each optical member 1 and the optical axis of each light source 280 may be shifted in the Y-axis direction, or may be shifted in both the X-axis direction and the Y-axis direction.

[0081] 12 to 17, the surface light source used in the light source module is described as having a substrate, but the substrate is provided as needed and can be omitted. For example, in the light source module, a surface light source in which a plurality of light-emitting elements are integrally held by a translucent resin or the like can be used.

[0082] (Liquid crystal display device) Fig. 18 is a partial cross-sectional view illustrating a liquid crystal display device having a light source module. Liquid crystal display device 400 shown in Fig. 18 has a light source module 300A and a liquid crystal panel 410. In liquid crystal display device 400, light emitted from light source module 300A is incident on liquid crystal panel 410, and an image is displayed on liquid crystal panel 410.

[0083] Since the light emitted from the light source module 300A has a deflected angle, for example, when the liquid crystal display device 400 is incorporated into a head-up display system and the installation angle of the light source module 300A is adjusted to remove distortion of the virtual image, the effect of optical axis misalignment occurring on the virtual image side can be suppressed.

[0084] In addition, in the liquid crystal display device 400, the light source module 300 or 300B may be used instead of the light source module 300A. Furthermore, when the light source module 300 is used in the liquid crystal display device 400, a prism sheet 320 may be disposed on the opposite side of the liquid crystal panel 410 from the light source module 300.

[0085] Although the preferred embodiments have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the claims.

[0086] In addition to the above-described embodiments, the following supplementary notes are also disclosed. (Appendix 1) A plurality of light control units are provided, Each of the light control units includes: an exit surface serving as the top surface; a first entrance surface located below the exit surface; a second entrance surface located on the outer periphery of the first entrance surface in a top view and extending downward from the first entrance surface; a reflecting surface located on the outer periphery of the second incident surface in a top view, the reflecting surface being inclined in a direction away from the center of the light control unit as it approaches the exit surface from the second incident surface side, light incident on the first entrance surface and the second entrance surface, and light reflected by the reflecting surface, is emitted from the exit surface; the first incident surface is a convex surface that curves in a direction away from the exit surface, the exit surface is a convex surface that curves in a direction away from the first entrance surface, In a cross-sectional view, the radius of curvature of the first incident surface is larger than the radius of curvature of the exit surface, An optical member in which the exit surfaces of adjacent light control sections are directly connected to each other. (Appendix 2) A plurality of light control units are provided, Each of the light control units includes: an exit surface serving as the top surface; a first entrance surface located below the exit surface; a second entrance surface located on the outer periphery of the first entrance surface in a top view and extending downward from the first entrance surface; a reflecting surface located on the outer periphery of the second incident surface in a top view, the reflecting surface being inclined in a direction away from the center of the light control unit as it approaches the exit surface from the second incident surface side, light incident on the first entrance surface and the second entrance surface, and light reflected by the reflecting surface, is emitted from the exit surface; the first entrance surface is a flat surface, the exit surface is a convex surface that curves in a direction away from the first entrance surface, An optical member in which the exit surfaces of adjacent light control sections are directly connected to each other. (Appendix 3) 3. The optical element according to claim 1, wherein the exit surface and the first entrance surface are square or rectangular in top view. (Appendix 4) When a vertical cross section taken through the center of the light exit surface and parallel to one side of the light exit surface is defined as a first cross section, and a vertical cross section taken along a diagonal line of the light exit surface is defined as a second cross section, 4. The optical member according to claim 3, wherein an angle formed between a center line of the light control portion and the reflecting surface is larger in the second cross section than in the first cross section. (Appendix 5) 5. The optical member according to claim 1, wherein the center of the first incident surface coincides with the center of the exit surface when viewed from above. (Appendix 6) When viewed from above, the exit surface is a rectangle having short sides and long sides, When a vertical cross section cut through the center of the rectangle parallel to the short side is defined as a third cross section, and a vertical cross section cut through the center of the rectangle parallel to the long side is defined as a fourth cross section, An optical element according to any one of claims 1 to 5, wherein the height from the lower end of the second incident surface of the portion where the exit surfaces of adjacent light control units contact is lower in the fourth cross section than in the third cross section. (Appendix 7) When viewed from above, the exit surface is a rectangle having short sides and long sides, When a vertical cross section cut through the center of the rectangle parallel to the short side is defined as a third cross section, and a vertical cross section cut through the center of the rectangle parallel to the long side is defined as a fourth cross section, 6. The optical element according to claim 1, wherein the radius of curvature of the exit surface is larger in the fourth cross section than in the third cross section. (Appendix 8) a surface light source including a substrate and a plurality of light sources arranged on the substrate; and the optical member according to any one of Supplementary Notes 1 to 7, arranged above the light source. (Appendix 9) 9. The light source module according to claim 8, wherein, in a top view, the center of the light source coincides with the center of the first incident surface. (Appendix 10) A liquid crystal display device comprising the light source module according to claim 8 or 9. [Explanation of symbols]

[0087] 1,1A Optical components 10 Optical control section 11. Exit surface 12,12A 1st entrance plane 13 Second entrance plane 14 Reflective surface 15 Connection Surface 20 Frame 200,200A surface light source 210 Substrate 220 Light-reflective material 280 light source 281 leads 282 Light-emitting element 283 Resin moldings 285 Sealing member 300, 300A, 300B Light Source Module 310 Diffusion Sheet 320 Prism Sheet 400 LCD display device 410 LCD panel

Claims

1. A plurality of light control units are provided, Each of the light control units includes: an exit surface serving as the top surface; a first entrance surface located below the exit surface; a second entrance surface located on an outer periphery of the first entrance surface in a top view and extending downward from the first entrance surface; a reflecting surface located on the outer periphery of the second incident surface in a top view, the reflecting surface being inclined in a direction away from the center of the light control unit as it approaches the exit surface from the second incident surface side, light incident on the first entrance surface and the second entrance surface and light reflected by the reflecting surface are emitted from the exit surface, the first incident surface is a convex surface that curves in a direction away from the exit surface, the exit surface is a convex surface that curves in a direction away from the first entrance surface, In a cross-sectional view, the radius of curvature of the first incident surface is larger than the radius of curvature of the exit surface, An optical member in which the exit surfaces of adjacent light control sections are directly connected to each other.

2. A plurality of light control units are provided, Each of the light control units includes: an exit surface serving as the top surface; a first entrance surface located below the exit surface; a second entrance surface located on an outer periphery of the first entrance surface in a top view and extending downward from the first entrance surface; a reflecting surface located on the outer periphery of the second incident surface in a top view, the reflecting surface being inclined in a direction away from the center of the light control unit as it approaches the exit surface from the second incident surface side, light incident on the first entrance surface and the second entrance surface and light reflected by the reflecting surface are emitted from the exit surface, the first incident surface is a flat surface, the exit surface is a convex surface that curves in a direction away from the first entrance surface, An optical member in which the exit surfaces of adjacent light control sections are directly connected to each other.

3. The optical member according to claim 1 , wherein the exit surface and the first entrance surface are square or rectangular in shape when viewed from above.

4. When a vertical cross section cut through the center of the light exit surface and parallel to one side of the light exit surface is defined as a first cross section, and a vertical cross section cut along a diagonal line of the light exit surface is defined as a second cross section, The optical member according to claim 3 , wherein an angle formed between a center line of the light control portion and the reflecting surface is larger in the second cross section than in the first cross section.

5. The optical member according to claim 1 , wherein a center of the first incident surface coincides with a center of the exit surface when viewed from above.

6. When viewed from above, the exit surface is a rectangle having short sides and long sides, When a vertical cross section cut through the center of the rectangle parallel to the short side is defined as a third cross section, and a vertical cross section cut through the center of the rectangle parallel to the long side is defined as a fourth cross section, The optical member according to claim 1 , wherein a height from a lower end of the second incident surface to a portion where the exit surfaces of adjacent light control portions contact each other is lower in the fourth cross section than in the third cross section.

7. When viewed from above, the exit surface is a rectangle having short sides and long sides, When a vertical cross section cut through the center of the rectangle parallel to the short side is defined as a third cross section, and a vertical cross section cut through the center of the rectangle parallel to the long side is defined as a fourth cross section, The optical member according to claim 1 , wherein the radius of curvature of the exit surface is larger in the fourth cross section than in the third cross section.

8. a surface light source including a substrate and a plurality of light sources arranged on the substrate; A light source module comprising: the optical member according to claim 1 or 2, disposed above the light source.

9. The light source module according to claim 8 , wherein a center of the light source coincides with a center of the first incident surface in a top view.

10. A liquid crystal display device comprising the light source module according to claim 8.

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