Optical member

Abstract

To provide an optical member capable of preventing a display from becoming worse in appearance by holding a smooth surface and a flat surface in parallel.SOLUTION: An optical member 1 comprises a light guide body 2 which has an incidence part 2a that ambient light impinges on, an emission part 2b which includes a surface that light impinging from the incidence part 2a reaches for the first time, and has a plurality of projection prism parts 4 and a plurality of flat surfaces 3 alternately arrayed, and a smooth surface 2c provided opposite the mission part 2b in parallel with the flat surfaces 3, and is made of light-transmissive material. Here, the direction in which the emission part 2b and smooth surface 2b are opposed to each other is represented as an X direction, the direction in which the prism parts 4 and flat surfaces 3 are alternately arrayed is represented as a Z direction, and the direction orthogonal to the X direction and Z direction is represented as a Y direction. The light guide body 2 further has a reinforcement part 2Rz which is protruded or recessed from the flat surfaces 3 or smooth surface 2c in the X direction and extends in the Z direction.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] Patent Document 1 proposes an optical member used as a blind spot assisting device for displaying an image in a blind spot area. This optical member has an incident portion where external light is incident, an exit portion in which a plurality of prism portions and a plurality of flat surfaces are arranged alternately, and a smooth surface provided opposite to the exit portion and parallel to the flat surface. This optical member guides light while totally reflecting the light incident from the incident portion by the flat surface and the smooth surface, and displays an image in the blind spot area by emitting the light from the plurality of prism portions provided in the exit portion.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the optical member described in Patent Document 1, for example, when the smooth surface undergoes a shape change such as warping or swelling due to aging or the like and the flatness decreases, the smooth surface and the flat surface may not be able to be kept parallel. In that case, display distortion and parallax occur, and deterioration in the appearance of the display becomes a problem. Further, since the optical member is an integrally formed light guide made of the same material or a light guide in which a plurality of materials are joined and integrated, it is difficult to correct only the shape change of the smooth surface.

[0005] In view of the above points, an object of the present disclosure is to provide an optical member capable of keeping the smooth surface and the flat surface parallel and preventing deterioration in the appearance of the display.

Means for Solving the Problems

[0006] According to one aspect of the present disclosure, an optical member that internally reflects and guides external light (L1) includes an incident portion (2a) where external light is incident, an emission portion (2b) including a surface where the light incident from the incident portion first arrives, and having a plurality of protruding prism portions (4) and a plurality of flat surfaces (3) arranged alternately, and a smooth surface (2c) provided opposite to the emission portion and parallel to the flat surface, and includes a light guide (2) formed of a light transmissive material. When the direction in which the emission portion and the smooth surface face each other is the X direction, the direction in which the prism portions and the flat surfaces are arranged alternately is the Z direction, and the direction orthogonal to the X direction and the Z direction is the Y direction, the light guide further has a reinforcing portion (2Rz) that protrudes or recesses in the X direction from the flat surface or the smooth surface and extends in the Z direction.

[0007] According to this, since the light guide has the reinforcing portion, the rigidity is increased, and it is possible to suppress the light guide from causing shape changes such as warping or swelling in the Z direction due to changes over time or the like. Therefore, it is possible to suppress a decrease in the flatness of the smooth surface and the flat surface and keep the smooth surface and the flat surface parallel. Accordingly, this optical member can prevent deterioration in the appearance of the display, such as display distortion and parallax.

[0008] In the present disclosure, "parallel" means a substantially parallel state, and includes not only a completely parallel state but also a state that is slightly different but substantially parallel due to manufacturing tolerances or the like.

[0009] According to another aspect of the present disclosure, an optical member that internally reflects and guides external light (L1) includes an incident portion (2a) where external light is incident, an emission portion (2b) including a surface where the light incident from the incident portion first arrives, and having a plurality of protruding prism portions (4) and a plurality of flat surfaces (3) arranged alternately, and a smooth surface (2c) provided opposite to the emission portion and parallel to the flat surface, and includes a light guide (2) formed of a light transmissive material. When the direction in which the emission portion and the smooth surface face each other is the X direction, the direction in which the prism portions and the flat surfaces are arranged alternately is the Z direction, and the direction orthogonal to the X direction and the Z direction is the Y direction, The incident part is composed of a plurality of incident prism parts (6) that extend in the Y direction and are arranged in the Z direction. The light guide further has a reinforcing part (2Rz) that protrudes or recesses in the X direction from a flat surface or a smooth surface and extends in the Z direction.

[0010] According to this, the optical member according to another aspect of the present disclosure also exhibits the same effects as the optical member according to one aspect of the present disclosure.

[0011] According to still another aspect of the present disclosure, an optical member that reflects and guides external scene light (L1) inside has an incident part (2a) where external scene light is incident, an emission part (2b) that includes a surface where the light incident from the incident part first arrives and where a plurality of protruding prism parts (4) and a plurality of flat surfaces (3) are alternately arranged, and a smooth surface (2c) that faces the emission part and is provided parallel to the flat surface, and includes a light guide (2) made of a light-transmissive material. When the direction in which the emission part and the smooth surface face each other is the X direction, the direction in which the prism parts and the flat surfaces are alternately arranged is the Z direction, and the direction orthogonal to the X direction and the Z direction is the Y direction, the light guide further has a reinforcing part (2Ry) that protrudes or recesses in the X direction from the smooth surface and extends in the Y direction. Let the refractive index of the medium outside the light guide be n 1 、 let the refractive index of the light guide be n 2 、 When the guiding angle, which is the included angle between the direction in which the light incident from the incident part travels inside the light guide and enters the flat surface and the smooth surface and the X direction, is Φ, the guiding angle is obtained by arcsin(n 1 / n 2 ) = Φ, the reinforcing part is provided in a region on the opposite side of the incident part in the Z direction from a line (ξ) where a virtual plane (DL) that passes through the position (4c) closest to the smooth surface among the prism parts arranged at the farthest position from the incident part in the Z direction and is inclined at the guiding angle with respect to the X direction intersects the smooth surface.

[0012] According to this, since the light guide has the reinforcing portion, its rigidity is increased, and it is possible to suppress the occurrence of shape changes such as warping and swelling in the Y direction due to changes over time or the like on the smooth surface and the flat surface. Therefore, it is possible to suppress a decrease in flatness of the smooth surface and the flat surface and keep the smooth surface and the flat surface parallel. Accordingly, this optical member can prevent deterioration in appearance of display, such as display distortion and parallax. Furthermore, this reinforcing portion (2Ry) is provided in a region that does not contribute to light guiding. Therefore, light is not caught by the second reinforcing portion 2Ry, and light scattering does not occur, so that it is possible to prevent a decrease in brightness of the display.

[0013] Note that the reference signs with parentheses attached to each component or the like indicate an example of the correspondence relationship between the component or the like and the specific components or the like described in the embodiments described later.

Brief Description of the Drawings

[0014]

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Embodiments for Carrying Out the Invention

[0015] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following embodiments, parts that are the same or equivalent to each other are denoted by the same reference numerals, and the description thereof will be omitted.

[0016] Note that FIGS. 1 to 25 referred to in the description of each embodiment simplify the configuration of each part of the optical member 1 and are drawn larger than the actual ones for the purpose of explanation. For FIG. 1, FIGS. 2 to 25 further simplify the configuration of each part of the optical member 1. Also, although FIG. 1 is a cross-sectional view of the optical member 1, the hatching indicating the cross-section is omitted for convenience of explanation.

[0017] (First Embodiment) The optical member 1 of the first embodiment will be described with reference to the drawings. 〔Basic Configuration〕 As shown in FIG. 1, the optical member 1 of the first embodiment is, for example, attached to a light-shielding body 100 or an obstacle that blocks the user's field of view and creates a blind spot, and can be used as a blind spot assisting device that allows the user to visually recognize the scene in the area of the blind spot.

[0018] As shown in FIGS. 1 to 3, the optical member 1 of the first embodiment includes a light guide 2 formed of a light-transmissive material. The light guide 2 constituting the optical member 1 has an incident portion 2a, an exit portion 2b, a smooth surface 2c, a terminal surface 2d, and a reinforcing portion 2Rz, and is capable of reflecting and guiding the external scene light L1 inside.

[0019] Hereinafter, for convenience of explanation, the external light incident on the incident portion 2a is referred to as "external scene light L1", the light incident from the incident portion 2a into the inside of the light guide 2 is referred to as "incident light L2", and the light emitted from the inside of the light guide 2 to the outside is referred to as "exit light L3".

[0020] The incident portion 2a is a surface for allowing the external scene light L1 to enter inside. The exit portion 2b is formed including the surface where the incident light L2 incident from the incident portion 2a first reaches, and has a configuration in which a plurality of protruding prism portions 4 and a plurality of flat surfaces 3 are arranged alternately. The smooth surface 2c is a surface facing the exit portion 2b and is provided parallel to the flat surface 3. The reinforcing portion 2Rz will be described later.

[0021] Hereinafter, for the convenience of explanation, the direction in which the flat surface 3 and the smooth surface 2c face each other is referred to as the "X direction". The X direction is perpendicular to the flat surface 3 and the smooth surface 2c. The X direction can also be referred to as the thickness direction of the light guide 2. Appropriately, the direction from the flat surface 3 side to the smooth surface 2c side is referred to as the +X direction, and the direction from the smooth surface 2c side to the flat surface 3 side may be referred to as the -X direction. Further, the direction in which the plurality of prism portions 4 and the plurality of flat surfaces 3 are alternately arranged is referred to as the "Z direction". The Z direction is perpendicular to the X direction. Appropriately, the direction from the incident portion 2a to the end surface 2d, that is, the direction in which the incident light L2 incident from the incident portion 2a is guided is referred to as the +Z direction, and the opposite direction is referred to as the -Z direction. Also, the direction perpendicular to the X direction and the Z direction is referred to as the "Y direction". The Y direction is the direction in which the plurality of prism portions 4 and the plurality of flat surfaces 3 extend respectively.

[0022] As shown in FIG. 1, in the optical member 1, a part of the incident light L2 incident from the incident portion 2a of the light guide 2 is reflected by the flat surface 3 of the emission portion 2b, and the light reflected by the flat surface 3 is reflected by the smooth surface 2c and then heads again toward the emission portion 2b side. The optical member 1 guides the incident light L2 incident from the incident portion 2a inside the light guide 2 and emits it to the outside from the prism portion 4 of the emission portion 2b. Thereby, the optical member 1 can enable a user on the emission portion 2b side to visually recognize the external scene in the dead angle area by the light shielding member 100 disposed on the smooth surface 2c side. Note that the light shielding member 100 is, for example, in the case of in-vehicle use, a member that causes a dead angle area such as an A-pillar of an automobile, but is not limited thereto and can be appropriately changed.

[0023] The light guide 2 is a substantially plate-shaped single member made of a light-transmissive material such as a resin material like polyethylene terephthalate, polycarbonate, polyethylene, acrylic, or glass. The light guide 2 is formed, for example, by resin injection molding. The light guide 2 is configured such that part of the incident light L2 enters the prism portion 4 of the light-emitting portion 2b, and the remaining part of the incident light L2 is reflected by the flat surface 3, and this reflected light is directed toward the smooth surface 2c. And the light guide 2 is designed such that the incident light L2 incident from the incident portion 2a into the inside of the light guide 2 is totally reflected by the smooth surface 2c and the flat surface 3 and is guided. Specifically, the refractive index of the medium (specifically air) outside the light guide 2 is n 1 , the refractive index of the constituent material of the light guide 2 is n 2 , when the incident angle of the incident light L2 with respect to the smooth surface 2c and the flat surface 3, that is, the light guide angle is Φ, it is designed to satisfy the following formula (1). Specifically, the light guide angle Φ is the inner angle formed by the direction in which the incident light L2 travels inside the light guide 2 and enters the flat surface 3 and the smooth surface 2c and the X direction. sinΦ > n 1 / n 2 ···(1) Thereby, the light guide 2 can repeatedly reflect part of the incident light L2 between the flat surface 3 and the smooth surface 2c and emit it to the outside from the emission surface 4a of the prism portion 4 without having a half mirror or a mirror made of a reflective material different from the light guide 2.

[0024] In the first embodiment, the incident portion 2a is a surface that intersects the light-emitting portion 2b and the smooth surface 2c. The incident portion 2a is inclined from the light-emitting portion 2b side toward the smooth surface 2c side to the end surface 2d side. Let the inner angle formed by the incident portion 2a and the X direction be the inclination angle Ψ. The inclination angle Ψ of the incident portion 2a is smaller than the light guide angle Φ. At this time, when the angle of the external scene light L1 with respect to the X direction is θ1, from the refraction condition, if Ψ < π / 2 - Φ, the incident light L2 is refracted in a direction in which the light guide angle Φ is larger than the angle θ1 of the external scene light L1, and is guided to a wider range of the light-emitting portion 2b. The angle θ1 can also be said to be the incident angle of the external scene light L1 with respect to the light guide 2. Since, for example, Φ becomes the total reflection angle in the light guide 2 and the refractive index of a normal light-transmissive resin material is 1.4 or more, n 2·Since sinΦ > 1, Φ > 45.3, and it has a structure that satisfies Φ > Ψ.

[0025] The emission part 2b is formed at a position adjacent to and intersecting the incident part 2a. The emission part 2b has a plurality of prism parts 4 which are, for example, triangular protrusions in a cross-sectional view, and a plurality of flat surfaces 3. The prism parts 4 and the flat surfaces 3 face from the incident part 2a toward the end face 2d and are arranged alternately.

[0026] The plurality of prism parts 4 protrude in the -X direction from the flat surface 3. The plurality of prism parts 4 have the same height Hp protruding in the -X direction and the same width Wp in the Z direction. In the present disclosure, "the same" means substantially the same, including not only completely the same but also a state that is almost the same with a slight difference due to manufacturing tolerances, etc. The plurality of prism parts 4 have an emission surface 4a that emits a part of the incident light L2 to the outside and another surface 4b adjacent to the emission surface 4a. The emission surfaces 4a of the plurality of prism parts 4 are surfaces parallel to the incident part 2a, and the inclination angle with respect to the X direction is Ψ. Thereby, the light that reaches the emission surface 4a among the incident light L2 is emitted to the outside as the emission light L3 at the same angle θ2 as the external scene light L1. For this reason, from the viewpoint of a user located on the emission part 2b side, the continuity between the external scene without passing through the optical member 1 and the external scene in the dead angle region that becomes visible by the optical member 1 (that is, the display by the optical member 1) is ensured. The plurality of prism parts 4, for example, have a constant interval between adjacent prism parts 4 in the Z direction (that is, the width Ws of the flat surface 3 in the Z direction).

[0027] The plurality of flat surfaces 3 face the smooth surface 2c and are formed parallel to the smooth surface 2c. In the present disclosure, "parallel" means a substantially parallel state, including not only completely parallel but also a state that is almost parallel with a slight difference due to manufacturing tolerances, etc. The plurality of flat surfaces 3 are arranged on the same plane. Since the incident light L2 from the incident part 2a is incident at an angle equal to or greater than the critical angle, the plurality of flat surfaces 3 function as reflection surfaces that reflect the incident light L2 toward the smooth surface 2c by total reflection.

[0028] The end face 2d is a surface that connects the light-emitting portion 2b and the smooth surface 2c. The inclination of the end face 2d is arbitrary. Note that the side surfaces 2f, which are located at both ends of the light guide 2 in the Y direction and connect the incident portion 2a, the light-emitting portion 2b, the smooth surface 2c, and the end face 2d, are surfaces that do not optically contribute, and their shapes, configurations, etc. are arbitrary. The above is the basic configuration of the optical member 1.

[0029] 〔Reinforcing portion 2Rz〕 Next, the reinforcing portion 2Rz will be described with reference to FIGS. 2 and 3.

[0030] When the smooth surface 2c of the light guide 2 that constitutes the above-described optical member 1 undergoes shape changes such as warping or swelling due to changes over time and the flatness decreases, the smooth surface 2c may not be kept parallel to the flat surface 3. In that case, display distortion and parallax occur, and deterioration of the appearance of the display becomes a problem.

[0031] Therefore, the optical member 1 has a reinforcing portion 2Rz at a portion on the smooth surface 2c side of the light guide 2. In the first embodiment, the reinforcing portion 2Rz is a convex-shaped portion that protrudes in the +X direction from the smooth surface 2c and extends in the Z direction. Further, the reinforcing portion 2Rz is provided at both ends of the smooth surface 2c in the Y direction. The reinforcing portion 2Rz is, for example, square-shaped in a cross-sectional view in the XY plane (in other words, a cross-sectional view perpendicular to the Z direction).

[0032] In the first embodiment, the reinforcing portion 2Rz is formed of the same material as the light-transmissive material that constitutes the light guide 2. The reinforcing portion 2Rz can be formed continuously and integrally with the light guide 2, for example, by resin injection molding. Note that, without being limited thereto, as described in (1) of the "Other Embodiments" described later, the reinforcing portion 2Rz may be formed of a material different from the light-transmissive material that constitutes the light guide 2 and may be configured to be joined to the light guide 2.

[0033] The reinforcing portion 2Rz of the first embodiment functions like a beam with respect to the light guide 2 and can enhance the rigidity of the light guide 2. The reinforcing portion 2Rz suppresses the occurrence of shape changes such as warping or swelling in the X direction in the Z direction due to changes over time or the like on the smooth surface 2c and the flat surface 3. Therefore, a decrease in the flatness of the smooth surface 2c and the flat surface 3 is suppressed, and the smooth surface 2c and the flat surface 3 can be kept parallel. Accordingly, this optical member 1 can prevent deterioration in the appearance of the display, such as display distortion and parallax.

[0034] (Second to Eighth Embodiments) The second to eighth embodiments are those in which the configuration of the reinforcing portion 2Rz is changed with respect to the first embodiment, and since the others are the same as those of the first embodiment, only the parts different from the first embodiment will be described.

[0035] (Second Embodiment) The second embodiment will be described. As shown in FIGS. 4 and 5, the reinforcing portion 2Rz included in the optical member 1 of the second embodiment has a groove shape that is recessed in the -X direction from the smooth surface 2c and extends in the Z direction, that is, a concave shape. The reinforcing portion 2Rz is provided at a position inside both side surfaces 2f in the Y direction of the light guide 2. The reinforcing portion 2Rz is formed integrally with the light guide 2 by, for example, resin injection molding. That is, the reinforcing portion 2Rz is formed of the same material as the light-transmissive material constituting the light guide 2.

[0036] The reinforcing portion 2Rz of the second embodiment enhances the rigidity of the light guide 2 due to its concave shape, thereby suppressing the occurrence of shape changes such as warping or swelling in the X direction in the Z direction due to changes over time or the like on the smooth surface 2c and the flat surface 3. Therefore, a decrease in the flatness of the smooth surface 2c and the flat surface 3 is suppressed, and the smooth surface 2c and the flat surface 3 are kept parallel. Accordingly, the optical member 1 can prevent deterioration in the appearance of the display.

[0037] (Third Embodiment) As shown in FIGS. 6 and 7, the optical member 1 of the third embodiment has a reinforcing portion 2Rz on the light-emitting portion 2b side of the light guide 2. The reinforcing portion 2Rz of the third embodiment protrudes from the flat surface 3 of the light-emitting portion 2b in the -X direction and extends in the Z direction. Further, the reinforcing portion 2Rz is provided outside the prism portion 4 of the light-emitting portion 2b in the Y direction and is connected to the prism portion 4. The reinforcing portion 2Rz is formed integrally with the light guide 2, for example, by resin injection molding. That is, the reinforcing portion 2Rz is formed of the same material as the light-transmissive material constituting the light guide 2.

[0038] The reinforcing portion 2Rz of the third embodiment functions like a beam with respect to the light guide 2 and can enhance the rigidity of the light guide 2. The reinforcing portion 2Rz suppresses the occurrence of shape changes such as warping or swelling in the X direction in the Z direction due to temporal changes or the like in the smooth surface 2c and the flat surface 3. Therefore, a decrease in the flatness of the smooth surface 2c and the flat surface 3 is suppressed, and it becomes possible to keep the smooth surface 2c and the flat surface 3 parallel. Accordingly, this optical member 1 can prevent deterioration in the appearance of the display, such as display distortion and parallax.

[0039] (Fourth Embodiment) The fourth embodiment is a modification of the first embodiment. As shown in FIG. 8, the optical member 1 of the fourth embodiment has a reinforcing portion 2Rz that protrudes from the smooth surface 2c in the +X direction and extends in the Z direction. The reinforcing portion 2Rz has a triangular shape in a cross-sectional view in the XY plane (in other words, a cross-sectional view perpendicular to the Z direction). The reinforcing portion 2Rz of the fourth embodiment also exhibits the same operational effects as those of the first embodiment.

[0040] (Fifth Embodiment) The fifth embodiment is also a modification of the first embodiment. As shown in FIG. 9, the optical member 1 of the fifth embodiment also has a reinforcing portion 2Rz that protrudes from the smooth surface 2c in the +X direction and extends in the Z direction. The surface of the reinforcing portion 2Rz facing the +X direction has a convex curved surface shape in a cross-sectional view in the XY plane (in other words, a cross-sectional view perpendicular to the Z direction). The reinforcing portion 2Rz of the fifth embodiment also exhibits the same operational effects as those of the first embodiment.

[0041] (Embodiment 6) Embodiment 6 will be described. As shown in FIGS. 10 and 11, the optical member 1 of Embodiment 6 also has a reinforcing portion 2Rz that protrudes in the +X direction from the smooth surface 2c and extends in the Z direction. In Embodiment 6, the width Wy of the light guide 2 in the Y direction is larger than the width Wpy of the prism portion 4 of the light emitting portion 2b in the Y direction. And the reinforcing portion 2Rz of Embodiment 6 is provided at a position outside the prism portion 4 of the light emitting portion 2b in the Y direction at the portion on the smooth surface 2c side of the light guide 2.

[0042] By the way, if the reinforcing portion 2Rz is provided at a position facing the prism portion 4 in the X direction, when guiding the incident light L2 in the Z direction while reflecting it with the flat surface 3 and the smooth surface 2c, the light is caught by the reinforcing portion 2Rz, and a phenomenon occurs in which light scattering occurs and the brightness of the display decreases.

[0043] On the contrary, in Embodiment 6, the reinforcing portion 2Rz is provided outside the prism portion 4 in the Y direction. Thereby, when guiding the incident light L2 in the Z direction while reflecting it with the flat surface 3 and the smooth surface 2c, the light is not caught by the reinforcing portion 2Rz and light scattering does not occur, so that a decrease in the brightness of the display can be prevented.

[0044] (Embodiment 7) Embodiment 7 will be described. As shown in FIGS. 12 and 13, in Embodiment 7, the reinforcing portion 2Ry is provided at a portion on the end surface 2d side on the smooth surface 2c side of the light guide 2. The reinforcing portion 2Ry protrudes in the +X direction from the smooth surface 2c and extends in the Y direction. In the following description, the reinforcing portion 2Rz extending in the Z direction described in the above Embodiments 1 to 6 may be referred to as the "first reinforcing portion 2Rz", and the reinforcing portion 2Ry extending in the Y direction described in this Embodiment 7 may be referred to as the "second reinforcing portion 2Ry".

[0045] In FIGS. 12 and 13, the regions where the second reinforcing portion 2Ry can be provided are indicated by arrows S1 and S2. This region is defined as follows.

[0046] First, the two-dot chain line DL in FIG. 12 indicates a virtual plane that passes through the position 4c closest to the smooth surface 2c among the prism portions 4 arranged at the position farthest from the incident portion 2a in the Z direction and is inclined at the light guiding angle Φ with respect to the X direction. The light guiding angle Φ is obtained by the following formula (2). arcsin(n 1 / n 2 ) = Φ ···(2) n 1 is the refractive index of the medium (specifically, air) outside the light guide 2, and n 2 is the refractive index of the light guide 2.

[0047] Next, ξ in FIG. 12 indicates the line at which the virtual plane indicated by the two-dot chain line DL intersects the smooth surface 2c. The region in the +Z direction with respect to that line ξ (i.e., the region on the end face 2d side with respect to the line ξ) is the region defined by the arrows S1 and S2. That region is a region in the smooth surface 2c that does not contribute to light guiding. The second reinforcing portion 2Ry is provided in that region.

[0048] Since the second reinforcing portion 2Ry provided in the optical member 1 of the seventh embodiment extends in the Y direction, it is possible to suppress the smooth surface 2c and the flat surface 3 from undergoing shape changes such as warping or swelling in the X direction in the Y direction due to temporal changes or the like. Therefore, a decrease in the flatness of the smooth surface 2c and the flat surface 3 is suppressed, and the smooth surface 2c and the flat surface 3 can be kept parallel.

[0049] Furthermore, the second reinforcing portion 2Ry provided in the optical member 1 of the seventh embodiment is provided in the region defined by the above arrows S1 and S2. That region is a region that does not contribute to light guiding. Therefore, light is not caught by the second reinforcing portion 2Ry and light scattering does not occur, so a decrease in the brightness of the display can be prevented.

[0050] (Eighth Embodiment) As shown in FIGS. 14 to 16, the optical member 1 of the eighth embodiment has the first reinforcing portion 2Rz described in the sixth embodiment and the second reinforcing portion 2Ry described in the seventh embodiment. The end portion on the end face 2d side of the first reinforcing portion 2Rz and the both end portions in the Y direction of the second reinforcing portion 2Ry are formed continuously.

[0051] In the optical member 1 of the eighth embodiment, the first reinforcing portion 2Rz and the second reinforcing portion 2Ry can suppress the smooth surface 2c and the flat surface 3 from undergoing shape changes such as warping or swelling in the X direction in the Z direction and the Y direction.

[0052] Furthermore, in the eighth embodiment, the first reinforcing portion 2Rz is provided outside the prism portion 4 in the Y direction, and the second reinforcing portion 2Ry is provided in the region defined by the arrows S1 and S2. Thereby, light is not caught by the first reinforcing portion 2Rz and the second reinforcing portion 2Ry, and light scattering does not occur, so that a decrease in the brightness of the display can be prevented.

[0053] (Ninth and Tenth Embodiments) The ninth and tenth embodiments are provided with a light absorption portion with respect to the first embodiment and the like, and since the other aspects are the same as those of the first embodiment and the like, only the portions different from the first embodiment and the like will be described.

[0054] (Ninth Embodiment) As shown in FIGS. 17 and 18, the reinforcing portion 2Rz included in the optical member 1 of the ninth embodiment is the same as that described in the sixth embodiment. Furthermore, the optical member 1 of the ninth embodiment includes a light absorption portion 5 that covers the reinforcing portion 2Rz. The light absorption portion 5 is composed of, for example, a black sheet that absorbs light or black painting. The light absorption portion 5 is provided at least at the corner portions of the reinforcing portion 2Rz. Specifically, the light absorption portion 5 is provided on the surface of the reinforcing portion 2Rz facing the +X direction and the surface facing the inner side in the Y direction. Note that when a holder (not shown) is provided on the side surface 2f of the light guide 2 facing the outside in the Y direction, the light absorption portion 5 is not necessary.

[0055] By the way, when the light absorption part 5 is not provided at the corner part of the reinforcing part 2Rz, when guiding the incident light L2 in the Z direction while reflecting it with the flat surface 3 and the smooth surface 2c, there is a concern that light reaches the corner part of the reinforcing part 2Rz and light scattering occurs, resulting in deterioration of the appearance of the display.

[0056] On the other hand, the optical member 1 of the ninth embodiment includes the light absorption part 5 that covers at least the corner part of the reinforcing part 2Rz, so that the light that reaches the corner part of the reinforcing part 2Rz is absorbed by the light absorption part 5. Therefore, this optical member 1 can prevent light scattering generated when light reaches the corner part of the reinforcing part 2Rz and prevent deterioration of the appearance of the display.

[0057] (Tenth Embodiment) As shown in FIGS. 19 and 20, the reinforcing part 2Rz included in the optical member 1 of the tenth embodiment has a groove shape that is recessed in the -X direction from the smooth surface 2c and extends in the Z direction, that is, a concave shape. The reinforcing part 2Rz is provided at a position outside the prism part 4 of the light emitting part 2b in the Y direction on the smooth surface 2c. The optical member 1 of the tenth embodiment also includes the light absorption part 5 that covers the corner part of the concave-shaped reinforcing part 2Rz. The light absorption part 5 is provided so as to cover the inner surface including the corner part of the concave-shaped reinforcing part 2Rz.

[0058] The optical member 1 of the tenth embodiment includes the light absorption part 5 that covers the inner surface including the corner part of the concave-shaped reinforcing part 2Rz, so that it can prevent light scattering generated when light reaches the reinforcing part 2Rz and prevent deterioration of the appearance of the display.

[0059] (Eleventh and Twelfth Embodiments) The eleventh and twelfth embodiments are configured such that the incident part 2a is composed of a plurality of incident prism parts 6 with respect to the first embodiment and the like, and since the other parts are the same as those of the first embodiment and the like, only the parts different from the first embodiment and the like will be described.

[0060] (Eleventh Embodiment) As shown in FIGS. 21 and 22, the incident portion 2a of the optical member 1 of the 11th embodiment is composed of a plurality of incident prism portions 6. The plurality of incident prism portions 6 protrude from the smooth surface 2c in the +X direction. The plurality of incident prism portions 6 each extend in the Y direction and are arranged in the Z direction. The joint portions between the plurality of incident prism portions 6 (i.e., the valleys of the plurality of incident prism portions 6) are provided on the same plane as the smooth surface 2c. In the following description, among the plurality of incident prism portions 6, the surface facing the side opposite to the end surface 2d is referred to as the "prism incident surface 6a", and the surface facing the end surface 2d side is referred to as the "other prism surface 6b". The inclination angle Ψ of the prism incident surface 6a is the same as the inclination angle Ψ of the incident portion 2a described in the 1st embodiment.

[0061] In the optical member 1 of the 11th embodiment, part of the incident light L2 incident from the plurality of prism incident surfaces 6a into the light guide 2 is reflected by the flat surface 3 of the emission portion 2b, the light reflected by the flat surface 3 is reflected by the smooth surface 2c, and then heads again toward the emission portion 2b side. The optical member 1 guides the incident light L2 incident from the plurality of prism incident surfaces 6a inside the light guide 2 and emits it to the outside from the prism portion 4 of the emission portion 2b. Thereby, the optical member 1 can enable a user on the emission portion 2b side to visually recognize the external view of the dead angle region by the light shielding body 100 arranged on the smooth surface 2c side.

[0062] The optical member 1 of the 11th embodiment has a first reinforcing portion 2Rz and a second reinforcing portion 2Ry. The first reinforcing portion 2Rz is provided outside the plurality of incident prism portions 6 in the Y direction. The end portion on the end surface 2d side of the first reinforcing portion 2Rz and the both end portions in the Y direction of the second reinforcing portion 2Ry are continuously formed. Also, the first reinforcing portion 2Rz is provided outside the prism portion 4 constituting the emission portion 2b in the Y direction.

[0063] The optical member 1 of the 11th embodiment can suppress the smooth surface 2c and the flat surface 3 from causing shape changes such as warping or bulging in the X direction in the Z direction and the Y direction by the first reinforcing portion 2Rz and the second reinforcing portion 2Ry.

[0064] Furthermore, in the eleventh embodiment, the first reinforcing portion 2Rz is provided outside the plurality of incident prism portions 6 in the Y direction, and is also provided outside the plurality of prism portions 4 constituting the emission portion 2b in the Y direction. The second reinforcing portion 2Ry is provided in the region defined by the arrows S1 and S2. As a result, the light guided by the light guide 2 does not catch on the first reinforcing portion 2Rz and the second reinforcing portion 2Ry, and light scattering does not occur, so that a decrease in display brightness can be prevented.

[0065] (Twelfth Embodiment) The twelfth embodiment is different from the eleventh embodiment in that the heights of the first reinforcing portion 2Rz and the second reinforcing portion 2Ry in the X direction are changed, and the rest is the same as the eleventh embodiment. Therefore, only the differences from the eleventh embodiment will be described.

[0066] As shown in FIG. 23, in the eleventh embodiment, let the height of the first reinforcing portion 2Rz and the second reinforcing portion 2Ry in the X direction be H, the distance between the flat portion and the smooth surface 2c be Hw, and the height of the plurality of incident prism portions 6 in the X direction be h. At this time, the following relationships of formulas (3) and (4) are satisfied. H≦3Hw ···(3) H>h ···(4)

[0067] According to the above formula (3), the height H of the first reinforcing portion 2Rz and the second reinforcing portion 2Ry in the X direction is set to be not more than three times the distance Hw between the flat portion and the smooth surface 2c. Thereby, when the light guide 2 is formed by resin injection molding, it is possible to suppress the mixing of air bubbles inside the first reinforcing portion 2Rz and the second reinforcing portion 2Ry, and furthermore, it is possible to suppress the defective demolding from the injection mold in the first reinforcing portion 2Rz and the second reinforcing portion 2Ry.

[0068] Also, according to the above formula (4), when the light guide 2 is stored in a holder (not shown), it is possible to prevent the vertices of the plurality of incident prism portions 6 from interfering with the inner surface of the holder and damaging the plurality of incident prism portions 6. Although not limiting the present disclosure, for example, it is preferable that Hw = 10 (mm), h = 1 (mm), and H = 0.1 + h (mm).

[0069] (Embodiment 13) Embodiment 13 is obtained by changing the number of reinforcing portions 2Rz with respect to Embodiment 6. Since other aspects are the same as those of Embodiment 6, only the differences from Embodiment 6 will be described.

[0070] As shown in FIGS. 24 and 25, the optical member 1 of Embodiment 13 has a plurality of reinforcing portions 2Rz that protrude in the +X direction from the smooth surface 2c and extend in the Z direction. Specifically, as shown in FIG. 25, two reinforcing portions 2Rz are provided at one end of the smooth surface 2c in the Y direction, and two reinforcing portions 2Rz are also provided at the other end of the smooth surface 2c in the Y direction. All of the plurality of reinforcing portions 2Rz are provided at positions outside the prism portion 4 of the light emitting portion 2b in the Y direction on the smooth surface 2c.

[0071] In Embodiment 13, the width of the light guide 2 in the Y direction is larger than the width of the prism portion 4 of the light emitting portion 2b in the Y direction. Therefore, a stepped surface 7 is provided outside the prism portion 4 of the light emitting portion 2b in the Y direction. All of the plurality of reinforcing portions 2Rz are provided at positions facing the stepped surface 7 in the X direction on the smooth surface 2c side of the light guide 2.

[0072] By the way, when the light guide 2 is formed by resin injection molding, if the volume of the reinforcing portion 2Rz is increased, there is a concern that a molding defect called sink marks may occur on the stepped surface 7.

[0073] On the other hand, in Embodiment 13, a plurality of reinforcing portions 2Rz on one side in the Y direction are configured of a plurality of members, and a plurality of reinforcing portions 2Rz on the other side in the Y direction are also configured of a plurality of members. Thereby, when the light guide 2 is formed by resin injection molding, molding defects on the stepped surface 7 can be alleviated.

[0074] (Other Embodiments) (1) In each of the above embodiments, the reinforcing portions 2Rz and 2Ry have been described as being formed of the same material as the light-transmissive material constituting the light guide 2, but the present invention is not limited thereto. For example, the reinforcing portions 2Rz and 2Ry may be formed of a material different from the light-transmissive material constituting the light guide 2 and joined to the light guide 2. In that case, as the material of the reinforcing portions 2Rz and 2Ry, for example, a metal such as aluminum, a resin such as polypropylene, rubber, or the like can be used. Note that hard rubber is preferable as the rubber. Thereby, the reinforcing portions 2Rz and 2Ry can be retrofitted to the light guide 2, measures can be taken to suppress a decrease in flatness of the smooth surface 2c and the flat surface 3, and the smooth surface 2c and the flat surface 3 can be kept parallel. Therefore, the optical member 1 can prevent deterioration in appearance of the display, such as display distortion and parallax.

[0075] (2) In the first, fourth, fifth embodiments, etc., the cross-sectional shapes of the reinforcing portion 2Rz are exemplified as a rectangular shape, a triangular shape, and a curved surface shape, but the present invention is not limited thereto, and the reinforcing portions 2Rz and 2Ry can adopt any shape.

[0076] (3) In the seventh, eighth embodiments, etc., the second reinforcing portion 2Ry has been described as a convex shape protruding in the +X direction from the smooth surface 2c, but the present invention is not limited thereto, and the second reinforcing portion 2Ry may be a concave shape recessed in the -X direction from the smooth surface 2c.

[0077] (4) In the thirteenth embodiment, etc., a plurality of the members provided on one side in the Y direction in the first reinforcing portion 2Rz are configured, and a plurality of the members provided on the other side in the Y direction are also configured, but the present invention is not limited thereto. For example, a plurality of the second reinforcing portions 2Ry may be configured.

[0078] The present disclosure is not limited to the above-described embodiments, and can be appropriately modified within the scope described in the claims. Also, each of the above embodiments and parts thereof are not unrelated to each other, and can be appropriately combined except when the combination is clearly impossible. Further, in each of the above embodiments, the elements constituting the embodiment are not necessarily essential except when it is clearly stated that they are essential or when they are considered to be clearly essential in principle. Also, in each of the above embodiments, when numerical values such as the number, numerical value, amount, range, etc. of the components of the embodiment are mentioned, they are not limited to the specific number except when it is clearly stated that they are essential or when they are clearly limited to a specific number in principle. Also, in each of the above embodiments, when referring to the shape, positional relationship, etc. of the components, etc., they are not limited to the shape, positional relationship, etc. except when it is clearly stated or when they are clearly limited to a specific shape, positional relationship, etc. in principle.

[0079] (Viewpoint of the present disclosure) The above-described present disclosure can be grasped, for example, from the viewpoints shown below. [First viewpoint] An optical member that internally reflects and guides external light (L1), an incident portion (2a) where the external light is incident, an emission portion (2b) including a surface where the light incident from the incident portion first arrives, and where a plurality of protruding prism portions (4) and a plurality of flat surfaces (3) are arranged alternately, and a smooth surface (2c) provided opposite to the emission portion and parallel to the flat surface, and comprising a light guide (2) made of a light-transmissive material, when the direction in which the emission portion and the smooth surface face each other is the X direction, the direction in which the prism portions and the flat surfaces are arranged alternately is the Z direction, and the direction orthogonal to the X direction and the Z direction is the Y direction, the light guide further has a reinforcing portion (2Rz) that protrudes or recesses in the X direction from the flat surface or the smooth surface and extends in the Z direction, an optical member. [Second viewpoint] An optical member that internally reflects and guides external light (L1), An incident portion (2a) for the external scene light to enter, an emission portion (2b) including a surface where the light incident from the incident portion first arrives, and where a plurality of protruding prism portions (4) and a plurality of flat surfaces (3) are arranged alternately, and a smooth surface (2c) provided facing the emission portion and parallel to the flat surface, and a light guide (2) made of a light-transmissive material is provided. When the direction in which the emission portion and the smooth surface face each other is the X direction, the direction in which the prism portions and the flat surfaces are arranged alternately is the Z direction, and the direction orthogonal to the X direction and the Z direction is the Y direction. The incident portion is composed of a plurality of incident prism portions (6) extending in the Y direction and arranged in the Z direction. The light guide further has a reinforcing portion (2Rz) that protrudes or recesses in the X direction from the flat surface or the smooth surface and extends in the Z direction, and is an optical member. [Third aspect] The reinforcing portion is configured to protrude in the X direction from the smooth surface. When the height of the reinforcing portion in the X direction is H and the distance in the X direction between the apexes of the plurality of incident prism portions and the smooth surface is h. The optical member according to the second aspect, having a relationship of H < h. [Fourth aspect] The optical member according to any one of the first to third aspects, wherein the reinforcing portion is provided at a position outside the prism portion in the Y direction of the light guide. [Fifth aspect] When the reinforcing portion is referred to as the first reinforcing portion. The light guide further has a second reinforcing portion (2Ry) that protrudes or recesses in the X direction from the smooth surface and extends in the Y direction. The refractive index of the medium outside the light guide is n 1 , The refractive index of the light guide is n 2 , When the guiding angle, which is the included angle between the direction in which the light incident from the incident portion travels inside the light guide and enters the flat surface and the smooth surface and the X direction, is Φ. The guiding angle is obtained by arcsin(n 1 / n 2 ) = Φ, The second reinforcing portion is provided in a region on the side opposite to the incident portion in the Z direction with respect to a line (ξ) where a virtual plane (DL) that passes through a position (4c) closest to the smooth surface among the prism portions arranged at the position farthest from the incident portion in the Z direction and is inclined at the light guiding angle with respect to the X direction intersects the smooth surface, and is the optical member according to any one of the first to fourth aspects. [Sixth aspect] The reinforcing portion is configured to protrude in the X direction from the smooth surface. When the height of the reinforcing portion in the X direction is H and the distance between the flat surface and the smooth surface is Hw, The optical member according to any one of the first to fifth aspects, having a relationship of H≦3×Hw. [Seventh aspect] The optical member according to any one of the first to sixth aspects, further including a light absorption portion (5) that covers a corner portion of the reinforcing portion. [Eighth aspect] The reinforcing portion is continuously formed with the light guide body by the same material as the light transmissive material constituting the light guide body, and is the optical member according to any one of the first to seventh aspects. [Ninth aspect] The reinforcing portion is configured to protrude in the X direction from the flat surface or the smooth surface. The reinforcing portion is formed of a material different from the light transmissive material constituting the light guide body and is joined to the light guide body, and is the optical member according to any one of the first to eighth aspects. [Tenth aspect] The reinforcing portion includes a plurality of members provided on one side in the Y direction and a plurality of members provided on the other side in the Y direction, and is the optical member according to any one of the first to ninth aspects. [Eleventh aspect] An optical member that reflects external light (L1) inside and guides the light. An incident part (2a) for the external scene light to enter, an emission part (2b) including a surface where the light incident from the incident part first arrives, in which a plurality of protruding prism parts (4) and a plurality of flat surfaces (3) are arranged alternately, and a smooth surface (2c) provided facing the emission part and parallel to the flat surface, and including a light guide (2) made of a light transmissive material. When the direction in which the emission part and the smooth surface face each other is defined as the X direction, the direction in which the prism parts and the flat surfaces are arranged alternately is defined as the Z direction, and the direction orthogonal to the X direction and the Z direction is defined as the Y direction. The light guide further has a reinforcing part (2Ry) that protrudes or recesses in the X direction from the smooth surface and extends in the Y direction. Let the refractive index of the medium outside the light guide be n 1 , Let the refractive index of the light guide be n 2 , When the guiding angle, which is the internal angle formed between the direction in which the light incident from the incident part travels inside the light guide and enters the flat surface and the smooth surface and the X direction, is defined as Φ. The guiding angle is obtained by arcsin(n 1 / n 2 ) = Φ, The reinforcing part is provided in a region on the opposite side of the incident part in the Z direction from a line (ξ) where a virtual plane (DL) that passes through the position (4c) closest to the smooth surface among the prism parts arranged at the position farthest from the incident part in the Z direction and is inclined at the guiding angle with respect to the X direction intersects the smooth surface, and is an optical member. [12th Aspect] The incident part is composed of a plurality of incident prism parts (6) that extend in the Y direction and are arranged in the Z direction, and is the optical member described in the 10th aspect.

[0080] It should be noted that it is also possible to combine the 1st to 10th aspects with respect to the 11th aspect or the 12th aspect.

Explanation of Reference Numerals

[0081] 1 Optical member 2 Light guide 2a Incident part 2b Emission part 2c Smooth surface 2Rz Reinforcement part 3 Flat surface 4 Prism part L1 Exterior light

Claims

1. An optical member that guides external light (L1) by reflecting it internally, comprising: an incident portion (2a) where the external light is incident; an emission portion (2b) including a surface where the light incident from the incident portion first arrives, and having a plurality of protruding prism portions (4) and a plurality of flat surfaces (3) arranged alternately; and a smooth surface (2c) provided opposite to the emission portion and parallel to the flat surface, and comprising a light guide (2) made of a light transmissive material. When the direction in which the emission portion and the smooth surface face each other is the X direction, the direction in which the prism portions and the flat surfaces are arranged alternately is the Z direction, and the direction orthogonal to the X direction and the Z direction is the Y direction, the light guide further has a reinforcing portion (2Rz) that protrudes or recesses in the X direction from the flat surface or the smooth surface and extends in the Z direction.

2. An optical member that guides external light (L1) by reflecting it internally, comprising: an incident portion (2a) where the external light is incident; an emission portion (2b) including a surface where the light incident from the incident portion first arrives, and having a plurality of protruding prism portions (4) and a plurality of flat surfaces (3) arranged alternately; and a smooth surface (2c) provided opposite to the emission portion and parallel to the flat surface, and comprising a light guide (2) made of a light transmissive material. When the direction in which the emission portion and the smooth surface face each other is the X direction, the direction in which the prism portions and the flat surfaces are arranged alternately is the Z direction, and the direction orthogonal to the X direction and the Z direction is the Y direction, the incident portion is composed of a plurality of incident prism portions (6) that extend in the Y direction and are arranged in the Z direction, the light guide further has a reinforcing portion (2Rz) that protrudes or recesses in the X direction from the flat surface or the smooth surface and extends in the Z direction.

3. The reinforcing portion protrudes in the X direction from the smooth surface. When the height of the reinforcing portion in the X direction is H and the distance in the X direction between the apexes of the plurality of incident prism portions and the smooth surface is h, the optical member according to Claim 2, having a relationship of H < h.

4. The optical member according to Claim 1 or 2, wherein the reinforcing portion is provided at a position outside the prism portion in the Y direction of the light guide.

5. When the reinforcing portion is referred to as the first reinforcing portion, the light guide further has a second reinforcing portion (2Ry) that protrudes or recesses in the X direction from the smooth surface and extends in the Y direction. The refractive index of the medium outside the light guide is n １ , Let the refractive index of the light guide be n ２ , When the angle of incidence of the light incident from the incident portion into the interior of the light guide is Φ, which is the internal angle formed by the direction of incidence on the flat surface and the smooth surface and the X direction, The light guiding angle is obtained by arcsin(n １ / n ２ ) = Φ, The second reinforcing portion is provided in a region on the opposite side of the incident portion in the Z direction from a line (ξ) where a virtual surface (DL) that passes through the position (4c) closest to the smooth surface among the prism portions arranged at the position farthest from the incident portion in the Z direction and is inclined at the angle of incidence with respect to the X direction intersects the smooth surface. The optical member according to claim 1 or 2.

6. The reinforcing portion has a configuration that protrudes in the X direction from the smooth surface, When the height of the reinforcing portion in the X direction is H and the distance between the flat surface and the smooth surface is Hw, The optical member according to claim 1 or 2, having a relationship of H ≦ 3 × Hw.

7. The optical member according to claim 1 or 2, further comprising a light absorption portion (5) that covers the corner portion of the reinforcing portion.

8. The optical member according to claim 1 or 2, wherein the reinforcing portion is formed continuously with the light guide by the same material as the light transmissive material constituting the light guide.

9. The reinforcing portion has a configuration that protrudes in the X direction from the flat surface or the smooth surface, The optical member according to claim 1 or 2, wherein the reinforcing portion is formed of a material different from the light transmissive material constituting the light guide and is joined to the light guide.

10. The optical member according to claim 1 or 2, wherein a plurality of the reinforcing portions provided on one side in the Y direction are configured, and a plurality of the reinforcing portions provided on the other side in the Y direction are also configured.

11. An optical member that reflects external scene light (L1) internally and guides the light, An incident portion (2a) where the external scene light is incident, an emission portion (2b) including a surface where the light incident from the incident portion first arrives, and a plurality of protruding prism portions (4) and a plurality of flat surfaces (3) arranged alternately, and a smooth surface (2c) provided opposite to the emission portion and parallel to the flat surface, and a light guide (2) formed of a light transmissive material. When the direction in which the emission portion and the smooth surface face each other is the X direction, the direction in which the prism portions and the flat surfaces are arranged alternately is the Z direction, and the direction orthogonal to the X direction and the Z direction is the Y direction, The light guide further has a reinforcing portion (2Ry) that protrudes or recesses in the X direction from the smooth surface and extends in the Y direction. Let the refractive index of the medium outside the light guide be n １ , Let the refractive index of the light guide be n ２ , When the light incident from the incident part travels inside the light guide, if the light guide angle, which is the inner angle formed between the direction of incidence on the flat surface and the smooth surface and the X direction, is Φ, The light guiding angle is obtained by arcsin(n １ / n ２ ) = Φ, The reinforcing part is an optical member provided in a region on the opposite side of the incident part in the Z direction from a line (ξ) where a virtual plane (DL) that passes through the position (4c) closest to the smooth surface among the prism parts arranged at the position farthest from the incident part in the Z direction and is inclined at the light guide angle with respect to the X direction intersects the smooth surface. [

12. ] The incident part is composed of a plurality of incident prism parts (6) that extend in the Y direction and are arranged in the Z direction, and the optical member according to claim 11.

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