Optical components

Abstract

To provide an optical member capable of improving the visibility of sight of a dead angle area.SOLUTION: An optical member 10 comprises a transparent material 20. The transparent material comprises: a first prism 70 including an incidence surface 72 which ambient light Lo enters from a dead angle area and a light-blocking surface 75 connected to the incidence surface 72 and which the ambient light Lo enters; a first reflection surface 31 reflecting light from the incidence surface 72; a second reflection surface 32 reflecting light reflected by the first reflection surface 31; and a second prism 40 including an emission surface 42 emitting light from the incidence surface 72 and light reflected by the second reflection surface 32 to the outside and a surface 45 intersecting with and connected to the emission surface 42 and receiving light from the light-blocking surface 75. The light-blocking surface 75 has a rough surface, and surface roughness of the rough surface is greater than surface roughness of the incidence surface 72.SELECTED DRAWING: Figure 16

Description

Technical Field

[0001] The present disclosure relates to an optical member.

Background Art

[0002] Conventionally, as described in Patent Document 1, a blind spot assisting device including a semi-transmissive mirror, a mirror, a light-transmissive member, and a plurality of prisms is known. The semi-transmissive mirror is provided on the viewer side. The mirror reflects light to the semi-transmissive mirror. The light-transmissive member is provided between the semi-transmissive mirror and the mirror. The plurality of prisms are provided between the semi-transmissive mirror and the viewer. Each prism has a light-shielding layer on a surface that does not face the light incident surface of the light-transmissive member. The light incident from the viewer side is blocked by this light-shielding layer.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] According to the study by the inventors, in the configuration of the blind spot assisting device described in Patent Document 1, in addition to the light incident from the viewer side becoming stray light, the light that passes through the incident surface of the light-transmissive member and is reflected at the interface between the prism and the light-shielding layer becomes stray light by passing through the emitting surface of the light-transmissive member. This stray light reduces the visibility of the scene in the blind spot area.

[0005] An object of the present disclosure is to provide an optical member that improves the visibility of the scene in the blind spot area.

Means for Solving the Problems

[0006] The invention described in claim 1 is an optical member comprising a light guide (20) having an incident surface (72) into which ambient light (Lo) from a blind spot region is incident and a light-shielding surface (75) connected to the incident surface into which ambient light is incident; a first prism (70) having an incident surface (72) into which ambient light is incident and a light-shielding surface (75) connected to the incident surface; a first reflective surface (31) that reflects light from the incident surface; a second reflective surface (32) that reflects light reflected by the first reflective surface; and a second prism (40) having an exit surface (42) that emits light from the incident surface and light reflected by the second reflective surface to the outside and a surface (45) connected to the exit surface intersecting with the exit surface into which light from the light-shielding surface is incident, wherein the light-shielding surface includes a rough surface (753), and the surface roughness of the rough surface is greater than the surface roughness of the incident surface.

[0007] As a result, when ambient light strikes the shading surface, the incident light is scattered by the rough surface. Therefore, the amount of light traveling from the shading surface toward the surface connected to the output surface decreases. Consequently, it becomes more difficult for light from the shading surface to reach the surface connected to the output surface. Therefore, since less light from the shading surface is reflected by the surface connected to the output surface, the light reflected by the surface connected to the output surface is less likely to reach the output surface. As a result, stray light is less likely to reach the viewer, improving the visibility of scenes in blind spots.

[0008] The reference numerals in parentheses attached to each component indicate an example of the correspondence between that component and the specific components described in the embodiments described later. [Brief explanation of the drawing]

[0009] [Figure 1] A diagram showing the configuration of a vehicle in which the optical component of the first embodiment is used. [Figure 2] Perspective view of an optical component. [Figure 3] Cross-sectional view of an optical component. [Figure 4] Enlarged view of section IV in Figure 3. [Figure 5] A schematic cross-sectional view showing the case when ambient light is incident on the incident surface of an optical component. [Figure 6]A schematic cross-sectional view showing the case when ambient light is incident on the incident surface of a comparative optical element. [Figure 7] Enlarged view of section VII in Figure 6. [Figure 8] A diagram showing the relationship between the angle of incidence and reflectance of light incident on a flat surface for comparison. [Figure 9] A schematic cross-sectional view showing what happens when light is incident on a rough surface of an optical component. [Figure 10] A diagram showing the relationship between root mean square height and reflectance. [Figure 11] A schematic cross-sectional view showing what happens when light from outside the optical component enters the light-shielding layer. [Figure 12] Cross-sectional view of the optical component of the second embodiment. [Figure 13] Enlarged view of section XIII in Figure 12. [Figure 14] Cross-sectional view of the optical component of the third embodiment. [Figure 15] Enlarged view of section XV in Figure 14. [Figure 16] A schematic cross-sectional view showing the case when ambient light is incident on the light-shielding surface of an optical component. [Figure 17] Enlarged view of section XVII in Figure 16. [Modes for carrying out the invention]

[0010] The embodiments will be described below with reference to the drawings. In the following embodiments, parts that are the same or equivalent to each other will be denoted by the same reference numeral, and their descriptions will be omitted.

[0011] (First Embodiment) The optical element 10 of this embodiment is used, for example, in a vehicle 1. As shown in Figure 1, the vehicle 1 includes a steering wheel 2, a front windshield 3, side windows 4, pillars 5, and the optical element 10, etc. The optical element 10 is attached to, for example, the pillar 5, and guides ambient light Lo from the blind spot area caused by the pillar 5 to the occupant of the vehicle 1, thereby allowing the occupant of the vehicle 1 to see the scenery in the blind spot area. The occupant of the vehicle 1 corresponds to the viewer.

[0012] Specifically, as shown in FIGS. 2 to 4, the optical member 10 includes a light guide 20 and a light shielding layer 60. In FIGS. 3, 4, and the cross-sectional views described later, the cross-sectional hatching of the optical member 10 is omitted for easy understanding.

[0013] The light guide 20 is formed of a light-transmissive material such as a resin material like polyethylene terephthalate, polycarbonate, polyethylene, and acrylic, or glass. Further, the light guide 20 has an incident surface 25, a first reflection surface 31, a second reflection surface 32, and a plurality of prisms 40.

[0014] The incident surface 25 is a surface on which external scene light Lo is incident. The first reflection surface 31 is disposed on the passenger side of the vehicle 1 and intersects the incident surface 25. Further, on the first reflection surface 31, the light from the incident surface 25 is reflected. The second reflection surface 32 is connected to the opposite side of the incident surface 25 from the first reflection surface 31 and is parallel to the first reflection surface 31. Furthermore, on the second reflection surface 32, the light reflected by the first reflection surface 31 is reflected.

[0015] Here, the direction of the normal line passing through the first reflection surface 31 is defined as the normal direction Dn. And the incident surface 25 is inclined with respect to the normal direction Dn. Further, the incident surface angle Asi, which is the inclination angle of the incident surface 25 with respect to the normal direction Dn, is an acute angle. Also, let the refractive index of the light guide 20 be n1. And let the refractive index of the external medium of the light guide 20 be n2. Furthermore, let the incident angle when the light from the incident surface 25 is reflected by the first reflection surface 31 and the incident angle when the light reflected by the first reflection surface 31 is reflected by the second reflection surface 32 be θi. At this time, the light guide 20 is formed so as to satisfy the following relational expression (1). Thereby, even if the light guide 20 does not have a semi-transmissive mirror, the light from the incident surface 25 is totally reflected by the first reflection surface 31 and the second reflection surface 32.

[0016] sinθi≧n2 / n1 ···(1)

[0017] Next, the prism 40 is formed during the formation of the light guide 20 by molding, cutting, blasting, and combinations thereof. The prism 40 protrudes from the first reflective surface 31 and is formed in a triangular prism shape. Furthermore, the prisms 40 are arranged at predetermined intervals. As a result, the first reflective surface 31 is arranged at predetermined intervals in the direction of the arrangement of the prisms 40. The prism 40 also includes a prism emission surface 42 and a prism light-shielding surface 45.

[0018] The prism emission surface 42 is connected to the first reflection surface 31. Furthermore, the prism emission surface 42 is parallel to the incident surface 25. Therefore, the prism emission surface 42 is inclined at an incident surface angle Asi with respect to the normal direction Dn. Additionally, the root mean square height of the prism emission surface 42 is, for example, 0.005 μm. Light from the incident surface 25 and light reflected by the second reflection surface 32 are emitted from the prism emission surface 42. The root mean square height is measured, for example, by a measurement method compliant with ISO 25178 and JIS B0601.

[0019] As will be described later, the prism shielding surface 45 is the surface to which light from the incident surface 25 and light reflected by the second reflection surface 32 are incident, and it blocks this incident light. In this way, the prism shielding surface 45 suppresses the light from becoming stray light GL. Specifically, the prism shielding surface 45 is connected to the prism exit surface 42 by intersecting it. Furthermore, as shown in Figure 4, the prism shielding surface 45 includes a flat surface 451 and a rough surface 453.

[0020] The flat surface 451 is connected to the first reflective surface 31. Furthermore, the root mean square height of the flat surface 451 is, for example, 0.005 μm.

[0021] The rough surface 453 is connected to the prism exit surface 42 and the flat surface 451. Furthermore, the root mean square height of the rough surface 453 is higher than the root mean square heights of the prism exit surface 42 and the flat surface 451. Therefore, the surface roughness of the rough surface 453 is greater than that of the prism exit surface 42 and the flat surface 451. Additionally, the root mean square height of the rough surface 453 is 0.1 μm or greater. Also, the ratio of the area of ​​the rough surface 453 to the area of ​​the prism shielding surface 45 is 50% or greater. Note that in Figure 4, the ratio of the area of ​​the rough surface 453 to the area of ​​the prism shielding surface 45 is 50%. Furthermore, while the ratio of the area of ​​the rough surface 453 to the area of ​​the prism shielding surface 45 is 50% or greater, the ratio of the width of the rough surface 453 to the width of the prism shielding surface 45 may also be 50% or greater.

[0022] The light-shielding layer 60 is a light-absorbing film that absorbs 99% or more of light. The light-shielding layer 60 is formed, for example, by painting, printing, and vapor deposition of a black resin. Furthermore, the light-shielding layer 60 covers the entire surface of each prism light-shielding surface 45. As a result, the light-shielding layer 60 blocks the light SL incident from the occupant side of the vehicle 1 toward the prism light-shielding surface 45, as will be described later. The light-shielding layer 60 covers the entire surface of the prism light-shielding surface 45, but is not limited to this, and may cover at least a part of the rough surface 453. Also, the light-shielding layer 60 is formed of a black resin, but is not limited to a black resin, and may be formed of a metal, for example.

[0023] As described above, the optical member 10 of the first embodiment is configured as described above. In the optical member 10 of this embodiment, the view in the blind spot area caused by the pillar 5 is visible to the occupants of the vehicle 1, and the visibility is improved. Next, the visibility of the view in the blind spot area will be described with reference to Figure 5.

[0024] For example, when ambient light Lo is incident on the incident surface 25 at an incident angle θo, it is refracted within the light guide 20 to become incident light Li. The incident angle θo is the angle between the direction of propagation of ambient light Lo and the normal direction Dn.

[0025] Furthermore, a portion of the incident light Li travels toward the first reflective surface 31 at an incident angle θi and reaches the first reflective surface 31. The incident light Li that reaches the first reflective surface 31 undergoes total internal reflection and becomes the first reflected light Lr1. The first reflected light Lr1 then travels toward the second reflective surface 32 at an incident angle θi and reaches the second reflective surface 32. The first reflected light Lr1 that reaches the second reflective surface 32 undergoes total internal reflection and becomes the second reflected light Lr2. Furthermore, the second reflected light Lr2 travels toward the prism emission surface 42 and reaches the prism emission surface 42. The second reflected light Lr2 that reaches the prism emission surface 42 is emitted from the prism emission surface 42 at an emission angle θu which is the same as the incident angle θo, and becomes the emitted light Lu. The emitted light Lu then travels toward the occupants of the vehicle 1 and reaches them, allowing them to see the scene in the blind spot area caused by the pillar 5. The incident angle θi is the angle between the direction of propagation of the incident light Li and the normal direction Dn. The exit angle θu is the angle between the direction of propagation of the exit light Lu and the normal direction Dn. Furthermore, since Asi < π / 2 - θi is satisfied, the incident angle θi is greater than the incident angle θo. As a result, the incident light Li propagates towards a wide area of ​​the first reflecting surface 31. In addition, the inclination angle of the prism shielding surface 45 with respect to the normal direction Dn is greater than or equal to the incident angle θo. Therefore, since the exit light Lu is emitted to the outside without being obstructed by the prism shielding surface 45, the loss of light intensity during emission is reduced.

[0026] Furthermore, a portion of the incident light Li travels toward the prism emission surface 42 and reaches it. The incident light Li that reaches the surface is then emitted from the prism emission surface 42 at an emission angle θu that is the same as the incidence angle θo, becoming emitted light Lu. As the emitted light Lu travels toward the occupants of the vehicle 1 and reaches them, the view in the blind spot area caused by the pillar 5 becomes visible.

[0027] As described above, the view in the blind spot area created by pillar 5 is visible to the occupants of vehicle 1. Next, we will explain how to improve the visibility of the view in the blind spot area.

[0028] Here, in order to explain the improvement in visibility by the optical component 10, a comparative optical component 900 will be described as a comparative example. As shown in Figures 6 and 7, the comparative optical component 900 comprises a comparative light guide 920 and a comparative light-shielding layer 960. The comparative light guide 920 corresponds to the light guide 20 and has a comparative incident surface 925, a comparative first reflective surface 931, a comparative second reflective surface 932, and a plurality of comparative prisms 940. The comparative incident surface 925 corresponds to the incident surface 25. The comparative first reflective surface 931 corresponds to the first reflective surface 31. The comparative second reflective surface 932 corresponds to the second reflective surface 32. The comparative prism 940 has a comparative exit surface 942. The comparative exit surface 942 corresponds to the prism exit surface 42. The comparative light-shielding layer 960 corresponds to the light-shielding layer 60. Therefore, a detailed explanation of these will be omitted.

[0029] Furthermore, the comparative prism 940 has a comparative flat surface 945 in addition to the comparative ejection surface 942. The comparative flat surface 945 is connected to the first reflective surface 31 and the comparative ejection surface 942 and is covered by the comparative light-shielding layer 960. Moreover, the root mean square height of the comparative flat surface 945 is less than or equal to the root mean square height of the comparative ejection surface 942.

[0030] Furthermore, the refractive index of the comparative light guide 920 is assumed to be 1.49. The refractive index of the comparative light shielding layer 960 is assumed to be 1.59. In this case, the difference in refractive index between the comparative light guide 920 and the comparative light shielding layer 960 is 0.1. In this case, when ambient light Lo is incident on the incident surface 25, the light from the comparative incident surface 925 and the light reflected by the comparative second reflective surface 932 may be reflected by the comparative flat surface 945. When the reflectance R reflected by the comparative flat surface 945 is calculated using Fresnel's reflection formula, as shown in Figures 7 and 8, the reflectance R increases as the incident angle θs of the light reaching the comparative flat surface 945 increases. Also, for example, when the incident angle θs is 86°, the reflectance R becomes as high as 40%. Here, the reflectance R is the sum of the amplitude reflectance of the p-wave of light and the amplitude reflectance of the s-wave of light.

[0031] Furthermore, the light reflected by the comparison flat surface 945 travels to and reaches the comparison emission surface 942. This arriving light is emitted from the comparison emission surface 942 and travels towards the occupants of vehicle 1, becoming stray light GL. This stray light GL reduces the visibility of the scene in the blind spot area.

[0032] In contrast, in the optical member 10 of this embodiment, the surface roughness of the rough surface 453 is greater than the surface roughness of the prism exit surface 42. As a result, as shown in Figure 9, when light from the incident surface 25 and light reflected by the second reflection surface 32 are incident on the prism light-shielding surface 45, the incident light is scattered by the rough surface 453 of the prism light-shielding surface 45. Therefore, the amount of light traveling from the prism light-shielding surface 45 toward the prism exit surface 42 is reduced. Consequently, light reflected by the prism light-shielding surface 45 is less likely to reach the prism exit surface 42. Thus, stray light GL is less likely to reach the occupants of the vehicle 1, improving the visibility of the scene in the blind spot area.

[0033] Furthermore, the optical element 10 of the first embodiment also provides the following effects.

[0034] [1-1] The prism shielding surface 45 includes a flat surface 451 and a rough surface 453. The ratio of the area of ​​the rough surface 453 to the area of ​​the prism shielding surface 45 is 50% or more. As a result, the area of ​​the rough surface 453 included in the prism shielding surface 45 is greater than or equal to the area of ​​the flat surface 451, which increases the probability that light from the incident surface 25 and light reflected by the second reflection surface 32 will be reflected by the rough surface 453. Therefore, light incident on the prism shielding surface 45 is more easily scattered, which tends to reduce the amount of light traveling from the prism shielding surface 45 toward the prism exit surface 42. Consequently, light reflected by the prism shielding surface 45 is less likely to reach the prism exit surface 42. Thus, stray light GL is less likely to reach the occupants of the vehicle 1, improving the visibility of the scene in the blind spot area.

[0035] [1-2] Here, the refractive index of the light guide 20 is assumed to be 1.49. The refractive index of the light-shielding layer 60 is assumed to be 1.59. In this case, the difference in refractive index between the light guide 20 and the light-shielding layer 60 is 0.1. Furthermore, assume that either the light from the incident surface 25 or the light reflected by the second reflecting surface 32 is incident on the rough surface 453 at an incident angle θs = 86°. In this case, as shown in Figure 10, the reflectance R at the prism light-shielding surface 45 decreases sharply as the root mean square height of the rough surface 453 increases. Also, when the root mean square height of the rough surface 453 is 0.005 μm, the reflectance R is 40%. Furthermore, when the root mean square height of the rough surface 453 is 0.1 μm or more, the reflectance R at the prism shielding surface 45 is 20% or less, which is less than half of the reflectance when the root mean square height of the rough surface 453 is 0.005 μm.

[0036] Therefore, in the optical element 10, the root mean square height of the rough surface 453 is 0.1 μm or more. As a result, the reflectance R is less than half compared to when the rough surface 453 is a smooth surface. Consequently, light reflected by the prism shielding surface 45 is less likely to reach the prism emission surface 42. Therefore, stray light GL is less likely to reach the occupants of the vehicle 1, improving the visibility of the scene in the blind spot area.

[0037] [1-3] The optical component 10 further includes a light-shielding layer 60 corresponding to the light-shielding portion. The light-shielding layer 60 covers the rough surface 453 and blocks light from outside the light guide 20. As a result, light from outside the light guide 20 on the prism 40 side is blocked, and as shown in Figure 11, stray light SL from outside the light guide 20 on the prism 40 side is suppressed.

[0038] Furthermore, the rough surface 453, whose root mean square height is higher than that of the prism exit surface 42, microscopically reduces the angle of incidence of light reaching the rough surface 453. As a result, light reaching the rough surface 453 is more likely to be refracted and propagate toward the light-shielding layer 60. Since the light that propagates toward the light-shielding layer 60 is blocked by the light-shielding layer 60, the amount of light propagating from the prism light-shielding surface 45 toward the prism exit surface 42 tends to decrease. Consequently, light reflected by the prism light-shielding surface 45 is less likely to reach the prism exit surface 42. Therefore, stray light GL is less likely to reach the occupants of the vehicle 1, improving the visibility of the scene in the blind spot area.

[0039] [1-4] The light-shielding layer 60 is a light-absorbing film that absorbs light. As a result, light from outside the light guide 20 on the prism 40 side is absorbed. Therefore, light from outside the light guide 20 on the prism 40 side is more easily blocked. Consequently, stray light SL from outside the light guide 20 is suppressed.

[0040] (Second Embodiment) In the second embodiment, as shown in Figure 12, the optical member 10 does not have a light-shielding layer 60. Otherwise, it is the same as in the first embodiment.

[0041] In this second embodiment, as shown in Figure 13, when light SL incident from the occupant side of the vehicle 1 travels to and reaches the rough surface 453, a portion of the light SL that reaches it is reflected by the rough surface 453, and the remaining portion is scattered. As a result, the amount of light SL decreases, and thus the light SL is blocked. Therefore, since the rough surface 453 blocks the light SL in place of the light-shielding layer 60, the same effects as in the first embodiment are achieved in the second embodiment as well. Furthermore, the second embodiment also achieves the effects described below.

[0042] [2] Since the optical component 10 does not have a light-shielding layer 60, the manufacturing process of the optical component 10 is shortened by the amount of the process required to form the light-shielding layer 60. This shortens the manufacturing time of the optical component 10 and reduces the cost of the optical component 10.

[0043] (Third embodiment) In the third embodiment, the light guide 20 does not have an incident surface 25. Furthermore, as shown in Figures 14 and 15, the light guide 20 further includes a plurality of incident prisms 70 in addition to the first reflective surface 31, the second reflective surface 32, and the plurality of prisms 40. In addition, the optical member 10 further includes an incident light-shielding layer 80 in addition to the light guide 20 and the light-shielding layer 60. Except for these, it is the same as the first embodiment. Note that the incident prisms 70 correspond to the first prism, and the prisms 40 correspond to the second prism.

[0044] The incident prism 70 is formed during the formation of the light guide 20 by molding, cutting, blasting, or a combination thereof. The incident prism 70 protrudes from the inside to the outside of the light guide 20 and is formed in a triangular prism shape. Furthermore, the incident prisms 70 are arranged at predetermined intervals. The incident prism 70 also includes a prism incident surface 72 and an incident light-shielding surface 75.

[0045] The prism incidence surface 72 is the surface to which ambient light Lo is incident. Furthermore, the prism incidence surface 72 is parallel to the prism emission surface 42 and intersects with the first reflection surface 31 and the second reflection surface 32. Additionally, the root mean square height of the prism incidence surface 72 is, for example, 0.005 μm. The inclination angle of the prism incidence surface 72 with respect to the normal direction Dn is the same as the incidence surface angle Asi.

[0046] As will be described later, the incident light-shielding surface 75 is the surface on which ambient light Lo is incident, and it blocks this incident light. In this way, the incident light-shielding surface 75 suppresses the light from being reflected by the incident light-shielding surface 75 and emitted from the prism exit surface 42 as stray light GLo. Specifically, the incident light-shielding surface 75 is connected to the prism incident surface 72 by intersecting it. The incident light-shielding surface 75 also includes an incident flat surface 751 and an incident rough surface 753.

[0047] Of the multiple incident flat surfaces 751, one on the side of the second reflecting surface 32 is connected to the second reflecting surface 32. The other incident flat surfaces 751 are connected to the inner portion of the light guide 20 of the prism incident surface 72. Furthermore, the root mean square height of the incident flat surfaces 751 is, for example, 0.005 μm.

[0048] The roughened incident surface 753 is connected to the outer portion of the light guide 20 on the prism incident surface 72 and to the flat incident surface 751. Furthermore, the root mean square height of the roughened incident surface 753 is higher than the root mean square heights of the prism incident surface 72 and the flat incident surface 751. Therefore, the surface roughness of the roughened incident surface 753 is greater than that of the prism incident surface 72 and the flat incident surface 751. Additionally, the root mean square height of the roughened incident surface 753 is 0.1 μm or greater. Also, the ratio of the area of ​​the roughened incident surface 753 to the area of ​​the light-shielding surface 75 is 50% or greater. Note that in Figure 15, the ratio of the area of ​​the roughened incident surface 753 to the area of ​​the light-shielding surface 75 is 50%. Furthermore, while the ratio of the area of ​​the incident rough surface 753 to the area of ​​the incident light-shielding surface 75 is 50% or more, the ratio of the width of the incident rough surface 753 to the width of the incident light-shielding surface 75 may also be 50% or more.

[0049] The incident light-shielding layer 80 is a light-absorbing film that absorbs 99% or more of light. The incident light-shielding layer 80 is formed, for example, by painting, printing, and vapor deposition of a black resin. Furthermore, the incident light-shielding layer 80 covers the entire surface of each incident light-shielding surface 75. In addition, as will be described later, the incident light-shielding layer 80 blocks light traveling from the blind spot side toward the incident prism 70. The incident light-shielding layer 80 covers the entire surface of the incident light-shielding surface 75, but is not limited to this, and may cover at least a part of the incident rough surface 753. Furthermore, the incident light-shielding layer 80 is formed of a black resin, but is not limited to a black resin, and may be formed of a metal, for example.

[0050] As described above, the optical member 10 of the third embodiment is configured as described above. This third embodiment also provides the same effects as the first embodiment. Furthermore, the third embodiment also provides the effects described below.

[0051] [3-1] Here, as shown in Figure 16, ambient light Lo may be incident on the incident light shielding surface 75 instead of the prism incident surface 72, and the incident light may be reflected by the prism shielding surface 45. When this reflected light is emitted from the prism exit surface 42 and travels towards the occupants of the vehicle 1, it becomes stray light GLo.

[0052] Therefore, in the optical member 10 of the third embodiment, the surface roughness of the incident rough surface 753 is greater than the surface roughness of the prism incident surface 72. As a result, as shown in Figure 17, when ambient light Lo is incident on the incident light shielding surface 75, the incident light is reflected and scattered by the incident rough surface 753. This reduces the amount of light traveling from the incident light shielding surface 75 toward the prism light shielding surface 45. Consequently, it becomes more difficult for light from the incident light shielding surface 75 to reach the prism light shielding surface 45. Therefore, since light from the incident light shielding surface 75 is less likely to be reflected by the prism light shielding surface 45, the light reflected by the prism light shielding surface 45 is less likely to reach the prism emission surface 42. As a result, stray light GLo is less likely to reach the occupants of the vehicle 1, improving the visibility of the scene in the blind spot area.

[0053] [3-2] The incident light-shielding surface 75 includes an incident flat surface 751 and an incident rough surface 753. Furthermore, the ratio of the area of ​​the incident rough surface 753 to the area of ​​the incident light-shielding surface 75 is 50% or more. As a result, the area of ​​the incident rough surface 753 included in the incident light-shielding surface 75 is greater than or equal to the area of ​​the incident flat surface 751, so the probability of ambient light Lo being reflected by the incident rough surface 753 is increased. Therefore, ambient light Lo incident on the incident light-shielding surface 75 is more likely to be reflected and scattered. As a result, the amount of light traveling from the incident light-shielding surface 75 toward the prism light-shielding surface 45 tends to decrease. Consequently, it becomes more difficult for light from the incident light-shielding surface 75 to reach the prism light-shielding surface 45. Therefore, as light from the incident light-shielding surface 75 is less likely to be reflected by the prism light-shielding surface 45, the light reflected by the prism light-shielding surface 45 is less likely to reach the prism exit surface 42. Therefore, stray light GLo is less likely to reach the occupants of vehicle 1, improving the visibility of the scene in the blind spot area.

[0054] [3-3] The root mean square height of the incident rough surface 753 is 0.1 μm or more. This makes it easier for ambient light Lo incident on the incident light-shielding surface 75 to be reflected and scattered. As a result, the amount of light traveling from the incident light-shielding surface 75 toward the prism light-shielding surface 45 tends to decrease. Consequently, it becomes more difficult for light from the incident light-shielding surface 75 to reach the prism light-shielding surface 45. Therefore, since it becomes less likely for light from the incident light-shielding surface 75 to be reflected by the prism light-shielding surface 45, the light reflected by the prism light-shielding surface 45 tends to reach the prism emission surface 42. As a result, stray light GLo is less likely to reach the occupants of the vehicle 1, improving the visibility of the scene in the blind spot area.

[0055] [3-4] The optical member 10 further includes an incident light-shielding layer 80 corresponding to the light-shielding portion. The incident light-shielding layer 80 covers the incident rough surface 753 and blocks light from outside the light guide 20. As a result, light from outside the light guide 20 on the blind spot side is blocked, and the conversion of ambient light Lo into stray light GLo is suppressed.

[0056] [3-5] The incident light-shielding layer 80 is a light-absorbing film that absorbs light. As a result, ambient light Lo traveling toward the incident light-shielding surface 75 is absorbed. Therefore, ambient light Lo traveling toward the incident light-shielding surface 75 is more easily blocked. Consequently, the conversion of ambient light Lo into stray light GLo is suppressed.

[0057] (Other embodiments) This disclosure is not limited to the embodiments described above, and modifications can be made to these embodiments as appropriate. Furthermore, it goes without saying that, in each of the embodiments described above, the elements constituting the embodiment are not necessarily essential, except in cases where they are explicitly stated to be particularly essential or where they are clearly considered essential in principle.

[0058] In each of the embodiments described above, the root mean square height is given as the surface roughness. However, the surface roughness is not limited to the root mean square height, and may also be the maximum peak height, maximum valley height, maximum height, and calculated average height, etc. The maximum peak height, maximum valley height, maximum height, and calculated average height, etc., are measured by measurement methods compliant with ISO 25178 and JIS B 0601, for example.

[0059] In the third embodiment described above, the prism shielding surface 45 of the prism 40 of the light guide 20 includes a rough surface 453, and the incident shielding surface 75 of the incident prism 70 of the light guide 20 includes an incident rough surface 753. In contrast, since the incident shielding surface 75 includes an incident rough surface 753, the prism shielding surface 45 does not need to include a rough surface 453.

[0060] In the third embodiment described above, the optical member 10 is provided with an incident light-shielding layer 80. In contrast, the optical member 10 does not need to be provided with an incident light-shielding layer 80. In this case, similar to the second embodiment, the incident rough surface 753 blocks the ambient light Lo instead of the incident light-shielding layer 80. Furthermore, since the optical member 10 does not have an incident light-shielding layer 80, the manufacturing process of the optical member 10 is shortened by eliminating the step of forming the incident light-shielding layer 80. As a result, the manufacturing time of the optical member 10 is shortened, and the cost of the optical member 10 is reduced.

[0061] In each of the above embodiments, the prism 40 and the incident prism 70 are triangular prisms, but are not limited to triangular prisms; for example, they may be trapezoidal prisms.

[0062] In each of the above embodiments, the light-shielding layer 60 and the incident light-shielding layer 80 are formed of a light-absorbing film, but are not limited to being formed of a light-absorbing film, and may be formed of a light-diffusing material, a retroreflective material, or the like.

[0063] In each of the above embodiments, the second reflective surface 32 is parallel to the first reflective surface 31. However, the second reflective surface 32 is not limited to being parallel to the first reflective surface 31, and may be configured not to be parallel to the first reflective surface 31 depending on the distance from the optical member 10 to the viewer. [Explanation of symbols]

[0064] 10 Optical components 20 Light guide 25, 75 entrance plane 31 1st reflective surface 32 Second reflective surface 40, 70 prism 42 Injection surface 45, 75 Shading Mask 453, 753 Rough surface 60, 80 light shielding layer

Claims

1. The light guide (20) comprises: a first prism (70) including an incident surface (72) into which ambient light (Lo) from a blind spot region is incident and a light-shielding surface (75) connected to the incident surface into which ambient light is incident; a first reflective surface (31) that reflects light from the incident surface; a second reflective surface (32) that reflects light reflected by the first reflective surface; and a second prism (40) including an exit surface (42) that emits light from the incident surface and light reflected by the second reflective surface to the outside, and a surface (45) connected to the exit surface intersecting with the exit surface into which light from the light-shielding surface is incident. The light-shielding surface includes a rough surface (753), An optical component in which the surface roughness of the roughened surface is greater than the surface roughness of the incident surface.

2. The light-shielding surface is connected to the rough surface and has a flat surface (451) whose surface roughness is less than that of the rough surface. The optical member according to claim 1, wherein the ratio of the area of ​​the rough surface to the area of ​​the light-shielding surface is 50% or more.

3. The optical member according to claim 1 or 2, wherein the root mean square height of the rough surface is 0.1 μm or more.

4. The optical member according to any one of claims 1 to 3, further comprising light-shielding portions (60, 80) that cover the rough surface and block light from outside the light guide.

5. The optical member according to claim 4, wherein the light-shielding portion is a light-absorbing film that absorbs light.

Images