Optical member

Abstract

Provided is an optical member provided with a light guide (2). The light guide has an incident surface (2a), an emission section (2b) that emits a portion of the light incident from the incident surface to the outside, and a smooth surface (2c) that faces the emission section, and the light guide is made of a translucent material. The emission section has a first region (2ba) adjacent to the incident surface and a second region (2bb) adjacent to the first region. The first region is formed by alternately and repeatedly arranging a plurality of stepped reflecting surfaces (4) provided such that a plurality of flat surfaces (41-43) facing the smooth surface are disposed at different heights across a stepped section (5), and a plurality of protruding prism sections (3). The flat surface and the smooth surface reflect, by total reflection, a portion of incident light incident from the incident surface to the inside of the light guide.

Description

Technical Field

[0001] The present disclosure relates to an optical member that reflects part of light incident from an incident surface internally and emits the incident light and its reflected light to the outside from a surface different from the incident surface. Background Art

[0002] At present, such an optical component is provided as a blind spot assisting device, which is mounted on a light shielding body, and allows external scene light from a blind spot area generated by the light shielding body to enter the inside and be reflected inside, so that the external scene light is emitted from a surface different from the incident surface of the external scene light, thereby enabling visual confirmation of the blind spot area. As such an optical component, for example, the optical component described in Patent Document 1 can be cited.

[0003] The optical member described in Patent Document 1 is composed of a light-transmitting light guide, and a portion of external light incident from an incident surface of the light guide is guided internally by total reflection and emitted to the outside from an emission portion different from the incident surface, thereby allowing a user on the emission surface side to visually recognize the outside scene at the blind spot. As a result, a half-mirror-free structure is achieved in which a half-mirror composed of a reflective material different from that of the light guide is not required on the emission portion side, and the loss caused by absorption of external light in the light guide inside the light guide can be reduced.

[0004] Prior Art Literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2023-028532 Summary of the invention

[0007] In the optical component described in Patent Document 1, the emitting portion has a plurality of prism portions and a plurality of flat portions in a protruding shape for emitting light to the outside, and the prism portions and the flat portions are alternately and repeatedly arranged along a direction connecting the incident surface and the terminal surface. Since the emitting portion of the optical component is a pattern structure of the prism portions and the flat portions, the incident light reaching the emitting portion generates reflected light corresponding to the pattern of the flat portions.

[0008] As a result of careful research on the optical component, the inventors of the present invention have newly discovered that the reflected light of a specified pattern generated by the emitting portion is guided by total reflection inside the light guide, and the interval between the patterns changes when it reaches the emitting portion again, and moiré fringes may be generated depending on the relationship with the structural pattern of the emitting portion.

[0009] The present disclosure is made in view of the above-mentioned points, and its purpose is to provide an optical component composed of a light guide that can guide incident light from an incident surface by total reflection and can suppress moiré fringes generated by the relationship between reflected light of a predetermined pattern at an emitting portion and the pattern structure of the emitting portion.

[0010] According to one viewpoint of the present disclosure, an optical component guides the external light by reflecting it internally, wherein the optical component comprises a light guide body made of a light-transmitting material, the light guide body comprises an incident surface for the external light to be incident, an emission portion for emitting a part of the light incident from the incident surface to the outside, a smooth surface opposite to the emission portion, and a terminal surface located on the side opposite to the incident surface and connecting the emission portion to the smooth surface, the emission portion comprising a first region adjacent to the incident surface and a second region adjacent to the first region, the first region comprising a plurality of stepped reflection surfaces and a plurality of The first area has a plurality of prism portions and a plurality of flat portions as one flat surface, and is formed by arranging the prism portions and the prism portions alternately and repeatedly. The step-shaped reflecting surface has a plurality of flat surfaces that are located at different heights across the step portions and are opposite to the surface formed by the smooth surface. The second area has a plurality of prism portions and a plurality of flat portions as one flat surface, and is formed by arranging the prism portions and the flat portions alternately and repeatedly. The flat surfaces, the flat portions and the smooth surfaces reflect a portion of incident light that is incident from the incident surface to the inside of the light guide body by total reflection. The prism portion has an emission surface that emits a portion of the incident light to the outside.

[0011] The optical component is designed to make the light incident from the incident surface incident on the stepped reflection surface arranged in the first area of ​​the emitting portion, split the light by a plurality of flat surfaces constituting the stepped reflection surface, reflect the light by total reflection, and guide the light to the second area of ​​the emitting portion. Thus, the optical component is in a state where the pitch interval of the reflected light reaching the second area is greatly different from the pattern interval of the prism portion and the flat portion in the second area, and the generation of moire fringes in the second area can be reduced.

[0012] According to another aspect of the present disclosure, an optical component guides the external light by reflecting it internally, wherein the optical component comprises: a light guide body, which is made of a light-transmitting material and has an incident surface for the external light to be incident, an emission portion having a plurality of protruding prism portions and a plurality of flat portions as flat surfaces and emitting a portion of the light incident from the incident surface to the outside, a smooth surface opposite to the emission portion, and a terminal surface located on the side opposite to the incident surface and connecting the emission portion to the smooth surface; and a plurality of refractive index difference layers, which are arranged on the light guide body. The light guide body has a plurality of flat surfaces arranged at different heights with a step portion in between and opposite to a plane formed by a smooth surface, and a region near an emission portion inside the body and where incident light incident from at least an incident surface directly enters. The plurality of refractive index difference layers have a refractive index lower than that of the light guide body. The flat surfaces, the flat portions, and the smooth surfaces reflect a portion of the incident light by total reflection. The prism portion has an emission surface that emits a portion of the incident light to the outside. The plurality of refractive index difference layers are arranged at a distance from each other in a manner that does not block light incident on the emission surface in the incident light.

[0013] The optical member is designed so that light is incident on the refractive index difference layer arranged near the emitting portion and arranged in a predetermined area for direct incidence of light incident from the incident surface, and is divided by a plurality of flat surfaces constituting the refractive index difference layer and reflected by total reflection, and is guided to an area in the emitting portion where no refractive index difference layer is arranged. Thus, the optical member is in a state where the pitch interval of reflected light reaching the area in the emitting portion where no refractive index difference layer is arranged is greatly different from the pattern interval of the prism portion and the flat portion in the area, and the generation of moire fringes in the area can be reduced.

[0014] According to another aspect of the present disclosure, an optical component guides external light by reflecting it internally, wherein the optical component includes a light guide body made of a light-transmitting material, the light guide body including an incident surface for incident external light, an emission portion having a plurality of protruding prism portions and a plurality of flat portions as flat surfaces and emitting a portion of light incident from the incident surface to the outside, a split reflection portion and a smooth surface opposite to the emission portion, and an end surface located on the side opposite to the incident surface and connecting the emission portion to the smooth surface, the split reflection portion being adjacent to the smooth surface and located closer to the incident surface than the smooth surface, and the split reflection portion being formed by repeatedly arranging a plurality of stepped reflection surfaces, a plurality of reflection surfaces in the stepped reflection surface that are opposite to a surface formed by a plurality of flat portions being located at different heights from each other across the step portions, the reflection surface, the flat portion and the smooth surface reflecting a portion of the incident light incident from the incident surface to the inside of the light guide body by total reflection, and the prism portion having an emission surface that emits a portion of the incident light to the outside.

[0015] The optical component is designed to allow light to be incident on a split reflection portion formed at an area where light reaches after being reflected from an area directly incident on light from an incident surface in the emission portion, and to be guided to the next area of ​​the emission portion by splitting the light using a plurality of reflection surfaces constituting the split reflection portion and reflecting it by total reflection.

[0016] Thus, the optical member is in a state where the pitch interval of reflected light reaching the next region of the emission portion is greatly different from the pattern interval of the prism portion and the flat portion in the next region, and the occurrence of moire fringes in the next region can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a cross-sectional view showing the optical member according to the first embodiment.

[0018] Figure 2 yes Figure 1 An illustration of light guidance in an optical component.

[0019] Figure 3 yes Figure 1 The enlarged view of region III is an illustration of light guidance in the first region of the emission portion.

[0020] Figure 4 is with Figure 3 The corresponding figures are explanatory diagrams regarding the pitch interval of the prism parts in the first region of the emission part, the pitch interval of the reflected light, and the height difference of the step part.

[0021] Figure 5 This is an explanatory diagram of light guide in an optical member of a comparative example that does not have a stepped flat portion.

[0022] Figure 6 About Figure 5 An explanatory diagram of the generation of moire fringes in an optical member of a comparative example.

[0023] Figure 7 It is a cross-sectional view showing an optical member according to a second embodiment.

[0024] Figure 8 yes Figure 7 An illustration of light guidance in an optical component.

[0025] Fig. 9 yes Figure 7 The enlarged view of the IX region is an illustration of the light guide in the first region of the emission portion.

[0026] Fig.10 is with Fig. 9 The corresponding figures are explanatory diagrams regarding the pitch interval of the refractive index difference layers in the first region of the emission portion, the pitch interval of the reflected light, and the height difference of the step portion.

[0027] Fig.11 It is a cross-sectional view showing a modified example of the optical member according to the second embodiment.

[0028] Fig.12 It is a cross-sectional view showing an optical member according to a third embodiment.

[0029] Fig.13 yes Fig.12 An illustration of light guidance in an optical component.

[0030] Fig.14 yes Fig.12 The enlarged view of region XIV is an illustration of light guidance in the first region of the emission portion.

[0031] Fig.15 is with Fig.14 The corresponding figures are explanatory diagrams regarding the pitch interval of the refractive index difference layers in the first region of the emission portion, the pitch interval of the reflected light, and the height difference of the step portion.

[0032] Fig.16 It is a cross-sectional view showing an optical member according to a fourth embodiment.

[0033] Fig.17 yes Fig.16 An illustration of light guidance in an optical component.

[0034] Fig.18 yes Fig.16 The enlarged view of region XVIII is an illustration of light guidance in the stepped reflection surface.

[0035] Fig.19 is with Fig.18 The corresponding figure is an explanatory diagram regarding the width of the stepped reflecting surface, the height difference of the step portion, and the inclination angle.

[0036] Fig. 20 It is a cross-sectional view showing an optical member according to another embodiment.

[0037] Fig.21 yes Fig. 20 An enlarged cross-sectional view of region XXI.

[0038] Fig. 22 It is a cross-sectional view showing an optical member according to another embodiment. DETAILED DESCRIPTION

[0039] Hereinafter, embodiments of the present disclosure will be described based on the drawings. In addition, in the following embodiments, the same or equivalent parts are denoted by the same reference numerals for description.

[0040] (First Embodiment)

[0041] An optical member 1 according to a first embodiment will be described with reference to the drawings.

[0042] 〔Basic structure〕

[0043] The optical member 1 of this embodiment can be used as a blind spot assist device, for example, which is mounted on a member or obstacle that blocks the user's field of vision or creates a blind spot, so that the user can visually recognize the scene in the blind spot area. For example, in the case of vehicle-mounted use, the optical member 1 is mounted on a predetermined light shielding body such as a pillar of the vehicle to guide the external scene light from the area that becomes a blind spot due to the pillar to the user side, so that the user can visually recognize the scene in the blind spot area.

[0044] The optical member 1 of this embodiment is, for example, Figure 1 The light guide 2 shown includes an incident surface 2a, an emission portion 2b, a smooth surface 2c, an inclined surface 2d and a terminal surface 2e.

[0045] For the sake of convenience, for example, Figure 1As shown, the direction along the normal direction with respect to the flat portion 6 or the smooth surface 2c described later in the optical member 1, that is, the direction connecting the emitting portion 2b and the smooth surface 2c facing each other is referred to as the "thickness direction D1". In addition, the direction from the incident surface 2a toward the terminal surface 2e, which is a direction orthogonal to the thickness direction D1, that is, the direction for guiding the light incident from the incident surface 2a is referred to as the "light guiding direction D2". In addition, the light guiding direction D2 is a direction along the direction in which the plurality of prism portions 3 and the flat portion 6 described later are repeatedly arranged, and is a direction orthogonal to the extending direction of the prism portions 3 and the flat portion 6, and can also be referred to as the arrangement direction.

[0046] For example Figure 2 As shown in FIG. 1 , the optical member 1 has a structure in which a part of the light incident from the incident surface 2a of the light guide 2 is reflected by the emission portion 2b, and the light reflected from the emission portion 2b is reflected by the smooth surface 2c and is directed toward the emission portion 2b side again. For example, the optical member 1 guides the external light from the incident surface 2a inside the light guide 2 and emits it from the emission portion 2b to the outside, thereby allowing a user located on the emission portion 2b side to visually recognize the outside scenery in the blind spot area formed by the light shielding body.

[0047] For the sake of convenience, the following Figure 2 As shown, the external light incident on the incident surface 2a is referred to as "external scene light L1", the light incident on the inside of the light guide 2 from the incident surface 2a 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". In addition, the light emitted from the first area 2ba of the emission portion 2b described later in the emission light L3 is referred to as "first emission light L31", the light emitted from the second area 2bb is referred to as "second emission light L32", and the light emitted from the third area 2bc is referred to as "third emission light L33".

[0048] The light guide 2 is a single member in a roughly plate-like shape made of, for example, a resin material such as polyethylene terephthalate, polycarbonate, polyethylene, acrylic acid, or a light-transmitting material such as glass. The light guide 2 is formed, for example, by a known resin molding method using a mold not shown in the figure. The light guide 2 has the following structure: a portion of the incident light L2 from the incident surface 2a is incident on the prism portion 3 of the emission portion 2b, and the remaining portion of the incident light L2 is reflected by the flat surfaces 41 to 43 or the flat portion 6 described later, and the reflected light is directed toward the smooth surface 2c. In addition, the light guide 2 is designed so that the incident light L2 reflected by the flat surfaces 41 to 43 or the flat portion 6 is totally reflected by the smooth surface 2c and the flat portion 6 and guided inside. Specifically, the light guide 2 sets the refractive index of its constituent material to n0 and sets the incident angle of the incident light L2 relative to the smooth surface 2c, the flat surfaces 41 to 43, and the flat portion 6 to φ. When the external medium of the light guide 2 is an air layer with a refractive index of 1, the design satisfies the following formula (1). Incident angle φ is the angle between the traveling direction of the incident light L2 incident on the flat surfaces 41 to 43, the flat portion 6, or the smooth surface 2c and the thickness direction D1, and may also be referred to as the light guide angle φ.

[0049] sinφ>1 / n0··· (1)

[0050] Therefore, even if the light guide 2 does not have a half-reflecting mirror or a reflecting mirror made of a reflective material different from the light guide 2, a part of the incident light L2 is repeatedly reflected between the flat portion 6 and the smooth surface 2c, and the incident light L2 is emitted to the outside from the later-described emission surface 3a of the prism portion 3.

[0051] The incident surface 2a is a surface that allows the external scene light L1 to be incident inside. The incident surface 2a is a surface that is adjacent to the emission portion 2b and extends in a direction that intersects the emission portion 2b and the smooth surface 2c. The incident surface 2a is, for example, a flat surface that is inclined in a manner that approaches the end surface 2e as it approaches the smooth surface 2c side and is inclined at an angle ψ with respect to the thickness direction D1. The inclination angle ψ of the incident surface 2a is smaller than the light guide angle φ. At this time, if the angle of the external scene light L1 relative to the thickness direction D1 is set to θ and ψ<π / 2-φ according to the refraction condition, the incident light L2 is refracted in a direction that makes the light guide angle φ larger than the angle θ of the external scene light L1 and is guided to a larger range of the emission portion 2b. The angle θ can also be said to be the incident angle of the external scene light L1 relative to the light guide body 2. The light guide 2 has, for example, the following structure: Since φ is the total reflection angle and the refractive index of a general light-transmitting resin material is 1.4 or more, φ>45.3 is obtained from n0·sinφ>1, which satisfies φ>ψ.

[0052] The emission portion 2b is formed at a position adjacent to and intersecting the incident surface 2a, for example, by having a first region 2ba, a second region 2bb, and a third region 2bc having different structures. The emission portion 2b is a so-called reflection emission surface that reflects a portion of the incident light L2 toward the smooth surface 2c side and emits a portion of the incident light L2 to the outside.

[0053] The first region 2ba has, for example, a plurality of prism portions 3 as protrusions in a triangular shape in cross-sectional view and a plurality of stepped reflecting surfaces 4 disposed between the prism portions 3, which are alternately and repeatedly arranged from the incident surface 2a toward the terminal surface 2e. The first region 2ba is a region into which the incident light L2 from the incident surface 2a is directly incident, that is, a region into which the incident light L2 from the incident surface 2a is incident without being reflected once.

[0054] The plurality of prism portions 3 are protrusions protruding from the stepped reflective surface 4, and are arranged, for example, in parallel, and in the present embodiment, the heights of the plurality of prism portions 3 in the thickness direction D1 and the widths in the light guiding direction D2 are substantially the same. In this specification, “substantially the same” includes not only the case of being completely the same, but also the case of being substantially the same although there are slight differences due to unavoidable reasons such as processing errors. The plurality of prism portions 3 are, for example, Figure 3 The figure shows an exit surface 3a which is parallel to the incident surface 2a in cross-sectional observation, that is, an exit surface 3a for emitting a part of the incident light L2 to the outside, and another surface 3b adjacent to the exit surface 3a. Among the multiple prism parts 3, for example, the exit surface 3a is parallel to the incident surface 2a, that is, the inclination angle relative to the thickness direction D1 is set to ψ. As a result, the light of the incident light L2 that reaches the exit surface 3a is emitted to the outside as the exit light L3 at the same angle θ as the external scene light L1. Therefore, the continuity between the external scene that does not pass through the optical component 1 when observed by the user located on the side of the exit part 2b and the external scene in the blind spot area that can be visually confirmed through the optical component 1 can be ensured. Among the multiple prism parts 3, for example, the spacing intervals between the adjacent prism parts 3 in the light guiding direction D2 are different in the first area 2ba, the second area 2bb and the third area 2bc. Hereinafter, the spacing intervals between the adjacent prism parts 3 in the light guiding direction D2 are referred to as "prism spacing". The prism pitch is fixed in, for example, the regions 2ba to 2bc.

[0055] The stepped reflecting surface 4 is composed of, for example, a first flat surface 41, a second flat surface 42, and a third flat surface 43, which are flat surfaces substantially parallel to the smooth surface 2c, and a step portion 5 disposed therebetween. In this specification, "substantially parallel" includes not only the case of being completely parallel but also the case of being substantially parallel despite unavoidable slight differences due to processing errors, etc.

[0056] Hereinafter, for convenience, the step portion 5 connecting the first flat surface 41 and the second flat surface 42 is referred to as a “first step portion 51 ”, and the step portion 5 connecting the second flat surface 42 and the third flat surface 43 is referred to as a “second step portion 52 ”.

[0057] The stepped reflecting surface 4 is formed, for example, by arranging the first flat surface 41, the first step portion 51, the second flat surface 42, the second step portion 52, and the third flat surface 43 in the order from the incident surface 2a side. The flat surfaces 41 to 43 of the stepped reflecting surface 4 function as reflecting surfaces that reflect the incident light L2. The stepped reflecting surface 4 is configured such that, for example, the positions of the flat surfaces 41 to 43 in the thickness direction D1 are different from each other, and the closer the flat surface of the prism portion 3 is to the end surface 2e side, the farther it is from the light guide 2. In addition, the prism portion 3 on the end surface 2e side refers to the prism portion 3 located on the end surface 2e side of the two prism portions 3 adjacent to the stepped reflecting surface 4.

[0058] In the following, for the sake of convenience, the position in the thickness direction D1 is referred to as the "height position", the direction from the injection portion 2b toward the smooth surface 2c along the thickness direction D1 is referred to as "up", and the direction from the smooth surface 2c toward the injection portion 2b is referred to as "down".

[0059] The stepped reflective surface 4 has a stepped structure in which, for example, the height position of the first flat surface 41 is substantially the same as that of the flat portion 6 and the height position gradually decreases in the order of the first flat surface 41, the second flat surface 42, and the third flat surface 43. The stepped reflective surface 4 is provided to suppress the phenomenon that, when the reflected light obtained by reflecting the incident light L2 reaches the second region 2bb, moire fringes are generated due to the difference between the pitch interval of the reflected light and the structural pitch of the prism portion 3 and the flat portion 6 in the second region 2bb. The details will be described later.

[0060] The second region 2bb, for example, has a plurality of prism portions 3 and a plurality of flat portions 6, which are alternately and repeatedly arranged from the incident surface 2a toward the end surface 2e. The plurality of flat portions 6 are, for example, flat surfaces that are opposite to the smooth surface 2c and arranged approximately parallel to the smooth surface 2c. The plurality of flat portions 6 are, for example, arranged on the same plane. Since the incident light L2 from the incident surface 2a is incident at an angle greater than the critical angle, the plurality of flat portions 6 function as a reflection surface that reflects the incident light L2 toward the smooth surface 2c side by total reflection. For example, when the prism pitch in the first region 2ba is set to PP1, the prism pitch in the second region 2bb becomes PP2 that is smaller than PP1. In other words, the width of the portion between adjacent prism portions 3 in the second region 2bb that reflects the incident light L2 in the light guide direction D2 is smaller than that of the first region 2ba.

[0061] The third region 2bc is composed only of a plurality of prisms 3 which are repeatedly arranged along the light guiding direction D2. The third region 2bc has no portion for reflecting the incident light L2 toward the smooth surface 2c, and serves as an emission region for emitting the incident light L2 that has reached the smooth surface 2c to the outside.

[0062] The emission portion 2b is constituted by, for example, regions 2ba to 2bc having different ratios of the reflection width in the light guide direction D2 of the incident light L2 to the width in the direction of the portion emitted to the outside, as described above, so that the light amount of the emitted light L31 to L33 can be made roughly uniform. The "roughly uniform" here includes not only the case where they are completely the same, but also the case where they are roughly the same although there are slight differences due to unavoidable reasons such as processing errors. In addition, in this specification, the case where the number of regions constituting the emission portion 2b is three is used as a representative example for explanation, but it is not limited to this, and the number of regions can be appropriately changed.

[0063] The inclined surface 2d is a surface connecting the incident surface 2a and the smooth surface 2c, and is, for example, a surface that is inclined at an inclination angle ξ relative to the thickness direction D1 in a manner that the closer it is to the smooth surface 2c, the closer it is to the end surface 2e, and that protrudes more than the smooth surface 2c. In other words, the incident surface 2a and the inclined surface 2d form a large protruding prism portion when observed in cross section. That is, the light guide 2 has a structure in which the height of a prism portion formed by the incident surface 2a and the inclined surface 2d in the thickness direction D1 is greater than the height T from the flat portion 6 of the emission portion 2b to the smooth surface 2c. As a result, the light guide 2 can expand the area in the emission portion 2b where the incident light L2 from the incident surface 2a initially reaches.

[0064] The terminal surface 2e is a surface connecting the emitting portion 2b and the smooth surface 2c. The terminal surface 2e is, for example, a flat surface. The inclination of the terminal surface 2e is arbitrary, and for example, it can also be a structure that forms a flat surface together with the emitting surface 3a of the prism portion 3 closest to the terminal surface 2e in the emitting portion 2b and functions as the last emitting surface in the light guide direction D2.

[0065] In addition, the side surfaces of the light guide 2 located at both ends in a direction orthogonal to the plane formed by the thickness direction D1 and the light guiding direction D2 and connecting the incident surface 2a, the emitting portion 2b, the smooth surface 2c, the inclined surface 2d and the end surface 2e are surfaces that do not contribute optically and may have any shape, structure, etc.

[0066] The above is the basic structure of the optical member 1 .

[0067] 〔Stepped reflective surface〕

[0068] Next, details of the stepped reflecting surface 4 and its effects will be described with reference to the drawings.

[0069] exist Figure 3 to Figure 5 In order to facilitate the understanding of light guidance in the optical component 1 and the optical components of the comparative examples described later, although no cross-section is shown, a shadow is applied to the light entering the interior of the optical component, and the travel directions of the incident light L2 and its reflected light are indicated by hollow arrows.

[0070] The stepped reflective surface 4 is, for example, Figure 3 As shown, incident light L2 is reflected by three flat surfaces 41 to 43 disposed across the step portion 5. In other words, the stepped reflective surface 4 divides the incident light L2 by a plurality of flat surfaces and reflects the incident light, and the pitch of the reflected light is set to be less than half of the prism pitch PP1.

[0071] In the following, for the sake of convenience, the light reflected by the first flat surface 41 in the incident light L2 is referred to as "first reflected light L21", the light reflected by the second flat surface 42 is referred to as "second reflected light L22", and the light reflected by the third flat surface 43 is referred to as "third reflected light L23".

[0072] In the stepped reflective surface 4, for example, the first step portion 51 and the second step portion 52 are set as flat inclined surfaces, and the inclined angles of the inclined surfaces relative to the thickness direction D1 are substantially the same. It is preferred that when the inclination angle of the steps 51 and 52 relative to the thickness direction D1 is set to η, the inclination angle η is less than the light guide angle φ of the incident light L2, that is, η≤φ is satisfied. As a result, the incident light L2 with the light guide angle φ will not be blocked by the steps 51 and 52 and reaches the second flat surface 42 and the third flat surface 43, which can suppress accidental reflection at the steps 51 and 52 and prevent light loss.

[0073] The step portions 51 and 52 are not limited to a planar shape as long as they do not obstruct the light of the incident light L2 directed toward the second flat surface 42 and the third flat surface 43 , and can be any shape such as a curved surface shape or a shape having a planar portion and a curved surface portion.

[0074] The stepped reflection surface 4, for example, divides the incident light L2 by the flat surfaces 41 to 43 to reflect the incident light, thereby setting the pitch intervals P11 to P13 of the reflected light L21 to L23 to be less than half of the prism pitch PP1. Figure 4The figure shows the spacing between the first reflected light L21 and the second reflected light L22 in the light guiding direction D2. The spacing interval P12 refers to the spacing between the second reflected light L22 and the third reflected light L23 in the light guiding direction D2. The spacing interval P13 refers to the spacing between the third reflected light L23 and the first reflected light L21 in another stepped reflective surface 4 adjacent to the third flat surface 43 generating the third reflected light L23 in the light guiding direction D2. The stepped reflective surface 4 suppresses the generation of moire fringes in the second region 2bb by dividing the incident light L2 into reflected lights L21 to L23 with spacing intervals P11 to P13 that are significantly different from the prism pitch PP1.

[0075] Here, for example Figure 5 As shown, the occurrence of moire fringes in an optical member of a comparative example that does not have the stepped reflecting surface 4 will be described.

[0076] The difference between the optical component of the comparative example and the optical component 1 is that the emitting portion is formed by repeatedly arranging a plurality of prism portions 100 as protrusions that are triangular in shape when observed in cross section and a plurality of flat portions 101 as flat surfaces alternately, and the prism pitch of the prism portion 100 is fixed in the entire region of the emitting portion. In other words, the optical component of the comparative example is configured so that the structural pitch of the prism portion and the flat portion in the emitting portion is the same in the entire region. The optical component of the comparative example totally reflects a portion of the incident light L2 toward the smooth surface side on the opposite side (not shown) by the flat portion 101, and emits a portion of the incident light L2 to the outside from the emitting surface 100a of the prism portion 100. The light reflected by the flat portion 101 in the incident light L2 is set to reflected light Lr1, and the pitch interval P of the reflected light Lr1 in the light guiding direction D2 is 1. Lr1 It is consistent with the prism pitch PP0 of the prism part 100 .

[0077] The reflected light Lr1 is guided inside the optical member of the comparative example and reaches the emission unit again. However, since there is a distance until it reaches the emission unit again, the pitch interval P of the reflected light Lr1 is Lr1 In the emission portion of the optical member of the comparative example, the region where the incident light L2 first reaches is set as the first region and the region where the incident light L2 reaches the second time after being reflected by the first region in the emission portion is set as the second region, and the pitch interval P of the second region is Lr1 The spacing P of the first area Lr1 Small.

[0078] On the other hand, in the optical member of the comparative example, the prism pitch PP0 is constant in the entire region of the emission portion. Therefore, in the second region, the prism pitch PP0 is constant in the entire region of the emission portion. Lr1 Therefore, the optical component of the comparative example, for example, Figure 6As shown, the light pattern of the reflected light in the second area slightly deviates from the structural pattern of the prism portion 100 and the flat portion 101, generating moiré fringes. If moiré fringes are generated, the visibility of the scene to be visually recognized in the emission portion is reduced, so the visibility of the scene in the blind spot area of ​​the optical component of the comparative example is reduced.

[0079] In addition, Figure 6 In the example, the light and dark of the light pattern and the light and dark of the structure pattern are shown with white and black patterns. Figure 6 In the figure, the "bright" part of the light pattern and the structure pattern corresponds to the part where the emitted light L3 is emitted, and the "bright" pattern is represented by white. Figure 6 In the figure, the “dark” part of the light pattern and the structural pattern corresponds to the part where the emitted light L3 is not emitted, and the “dark” pattern is represented by black. Figure 6 1 shows a light-dark pattern when viewed from the normal direction with respect to the flat portion 101 of the emission portion.

[0080] The spacing P of the moiré fringes in the reflected light Lr1 Lr1 When the difference from the prism pitch PP0 is less than the specified value, the moiré fringes will be significantly generated. If the difference becomes larger, the period of the moiré fringes will become thinner and less noticeable. Lr1 Therefore, in order to reduce moire fringes, it is considered that the prism pitch PP0 in the first region is sufficiently smaller than that in the second region in the optical member of the comparative example.

[0081] However, in this case, the size of the prism portion 100, and thus the area of ​​the emission surface 100a, will be reduced, and the diffraction effect of the emission light L3 in the first area due to the reduction in the area of ​​the emission surface 100a will be increased. Therefore, when only the prism pitch PP0 in the first area is reduced, the moire fringes can be reduced, but the blur of the scene visually recognized in the first area becomes larger, and the visual recognition of the scene in the blind spot area is reduced.

[0082] In contrast, the optical member 1 of the present embodiment has a structure in which a plurality of stepped reflection surfaces 4 are arranged in the first region 2ba of the emission portion 2b to divide the incident light L2 into a plurality of reflected lights L21 to L23. Therefore, for the reflected lights L21 to L23, the pitch intervals P11 to P13 are greatly different from the prism pitch PP1, and the difference between the pitch intervals P11 to P13 and the prism pitch PP2 becomes larger when the reflected lights L21 to L23 reach the second region 2bb. As a result, the optical member 1 can suppress the generation of moire fringes in the second region 2bb.

[0083] In addition, the optical component 1 has a structure in which the height position of the stepped reflecting surface 4 is lowered as the flat surface is closer to the terminal surface 2e, thereby ensuring a large area of ​​the emitting surface 3a of the prism portion 3. Therefore, in the optical component 1, the influence of diffraction of the emitted light L3 due to the area of ​​the emitting surface 3a is reduced, and the reduction in the visual recognition of the scene visually recognized at the emitting portion 2b can be suppressed.

[0084] In addition, if Figure 4 As shown, the widths of the reflected lights L21 to L23 in the light guiding direction D2 are respectively set to S11, S12, and S13, and the widths of the step portions 51 and 52 in the thickness direction D1 are set to D31 and D32. At this time, the pitch intervals P11 and P12 in the first region 2ba are expressed by the following equations (2) and (3).

[0085] P11=S11+2×D31×tanφ· · · (2)

[0086] P12=S12+2×D32×tanφ···(3)

[0087] In this specification, the case where the stepped reflective surface 4 has a structure with three flat surfaces is used as a representative example for explanation, but it is not limited to this. The number of steps is set to m (m is an integer greater than or equal to 2) and the number of flat surfaces is set to m+1. m can be changed appropriately. For example, the reflected light at the m-th flat surface 4m counted from the incident surface 2a side in the stepped reflective surface 4 is set to the m-th reflected light L2m, and the reflected light at the (m+1)-th (m+1)-th flat surface 4(m+1) is set to the (m+1)-th reflected light L2(m+1). In addition, the widths of the m-th reflected light L2m and the (m+1)-th reflected light L2(m+1) in the light guiding direction D2 are set to S1m and S1(m+1), respectively, and the width of the m-th step 5m counted from the incident surface 2a side in the thickness direction D1 is set to D3m. At this time, the pitch interval P1m between the m-th reflected light L2m and the (m+1)-th reflected light L2(m+1) in the first region 2ba is expressed by the following formula (4).

[0088] P1m=S1m+2×D3m×tanφ· · · (4)

[0089] In addition, from the perspective of reducing moiré fringes, the pitch intervals P11 to P1m only need to be less than half of the prism pitch PP1, and do not need to be substantially the same. However, when they are substantially the same, the effect of making the light amount of the emitted light L3 substantially uniform can be obtained. This is because, when the pitch intervals P11 to P1m are substantially the same, the first reflected light L21 to the mth reflected light L2m directed toward the second region 2bb become substantially equally spaced, that is, the light amount becomes substantially the same, which can reduce the fluctuation of the light amount emitted from the second region 2bb and the third region 2bc. When the pitch intervals P11 to P1m are set to be substantially the same, the widths D31 to D3m of, for example, the first step portion 51 to the mth step portion 5m in the stepped reflective surface 4 are set to be substantially the same, and the widths S11 to S1(m+1) of the first flat surface 41 to the (m+1)th flat surface 4(m+1) are set to be substantially the same.

[0090] Furthermore, since the step portion 5 of the stepped reflecting surface 4 and the other surface 3 b of the prism portion 3 are surfaces that do not contribute optically, they may be covered with a light shielding film (not shown) to prevent external light from the emitting portion 2 b from entering the light guide 2 .

[0091] According to the present embodiment, the optical member 1 is as follows: the first region 2ba of the emission portion 2b, into which the incident light L2 from the incident surface 2a directly enters, is alternately and repeatedly arranged with the prism portion 3 and the stepped reflection surface 4, and a part of the incident light L2 is divided and reflected by the plurality of flat surfaces 41 to 43. The optical member 1 is in a state where a part of the incident light L2 is divided into a plurality of reflected lights L21 to L23, and the pitch intervals P11 to P13 of the reflected lights L21 to L23 are greatly deviated from the prism pitch PP1 of the prism portion 3. Therefore, in the optical member 1, the pitch intervals P11 to P13 of the reflected lights L21 to L23 are greatly deviated from the prism pitch PP2 of the second region 2bb, and moiré fringes can be reduced.

[0092] (1) The optical component 1 has the following structure in this embodiment: the flat surface of the prism portion 3 closer to the end surface 2e side among the flat surfaces 41 to 43 of the stepped reflective surface 4 is located lower in the thickness direction D1. As a result, the optical component 1 can ensure that the area of ​​the emission surface 3a of the prism portion 3 is greater than a predetermined area, and can reduce the diffraction effect of the emission light L3 in the first area 2ba. In other words, the optical component 1 can reduce the moire fringes caused by the periodic structure of the prism portion 3 and the total reflection reflection surface, and can ensure the visual confirmation of the scene in the blind spot area.

[0093] (Second Embodiment)

[0094] Reference Figure 7 to Figure 10 An optical member 1 according to the second embodiment will be described.

[0095] exist Fig. 9 , Fig.10 In, due to Figure 3 For the same purpose, although the cross section is not shown, the incident light L2 and the reflected light L21 to L23 in the optical member 1 are shaded and the traveling directions of these lights are indicated by hollow arrows.

[0096] The optical member 1 of this embodiment is, for example, Figure 7 The present embodiment is different from the first embodiment described above in that the structure of the emission portion 2b is changed and a refractive index difference layer 7 is provided inside the light guide 2. In the present embodiment, these differences will be mainly described.

[0097] In the present embodiment, the emission portion 2b is formed by, for example, arranging prism portions 3 and flat portions 6 alternately and repeatedly in the same manner as in the first region 2ba and the second region 2bb. The prism pitch PP1 of the prism portion 3 of the first region 2ba is larger than the prism pitch PP2 of the second region 2bb. In the present embodiment, the first region 2ba is provided with a refractive index difference layer 7 having a lower refractive index than that of the light guide 2, inside the light guide 2 and near the flat portion 6 on the emission portion 2b side. Since the flat portion located in the first region 2ba among the plurality of flat portions 6 does not need to function as an internal reflection surface, it may be covered with a light-shielding film (not shown) in order to prevent external light from the emission portion 2b side from intruding into the interior.

[0098] The optical member 1 is, for example, Figure 8 As shown in the design, a part of the incident light L2 is reflected toward the smooth surface 2c by total reflection at the interface between the light guide 2 and the refractive index difference layer 7 in the first region 2ba, and the remaining part passes through the gap of the refractive index difference layer 7 and is emitted to the outside from the emission surface 3a of the prism portion 3. The incident light L2 incident on the refractive index difference layer 7 is divided and reflected by the flat surfaces 71 to 73 of the refractive index difference layer 7 described later. The incident light L2 reflected by the refractive index difference layer 7 is totally reflected by the smooth surface 2c in the same manner as in the first embodiment, and then guided to the second region 2bb or the third region 2bc and emitted to the outside from the prism portion 3.

[0099] The refractive index difference layer 7 is composed of, for example, a low refractive index material having a refractive index n1 (<n0) relatively low compared to the light guide 2, or an air layer. Thus, the refractive index difference layer 7 satisfies the total reflection condition of sinφ>n1 / n0 or sinφ>1 / n0, and reflects the incident light L2 incident on the flat surfaces 71 to 73. The refractive index difference layer 7 is, for example, Fig. 9As shown, the refractive index difference layer 7 is formed by having a plurality of flat surfaces 71 to 73 substantially parallel to the smooth surface 2c and a step portion 8 connecting the flat surfaces. In the refractive index difference layer 7, for example, the surface on the opposite side to the emission portion 2b is sequentially formed from the incident surface 2a side into a first flat surface 71, a first step portion 81, a second flat surface 72, a second step portion 82, and a third flat surface 73. The refractive index difference layer 7 is formed by having, for example, a plurality of flat surfaces 71 to 73 at different height positions, but from the viewpoint of ensuring the area of ​​the emission surface 3a in the first region 2ba, it is preferably configured such that the flat surface closer to the terminal surface 2e has a lower height position, that is, closer to the emission portion 2b.

[0100] In this embodiment, the light guide 2 can be manufactured by a resin molding method, for example, by using a mold not shown to mold the portion from the smooth surface 2c side to the flat surfaces 71 to 73 and the stepped portions 81 and 82 that become the refractive index difference layer 7, and then using a different mold to mold the remaining portion.

[0101] The first flat surface 71 is, for example, a reflecting surface that is located at the highest height among the multiple flat surfaces of the refractive index difference layer 7 and reflects a part of the incident light L2 as the first reflected light L21 by total reflection. The second flat surface 72 is, for example, a reflecting surface that is located at a height between the first flat surface 71 and the third flat surface 73 and reflects a part of the incident light L2 as the second reflected light L22 by total reflection. The third flat surface 73 is, for example, a reflecting surface that is located at the lowest height among the multiple flat surfaces of the refractive index difference layer 7 and reflects a part of the incident light L2 as the third reflected light L23 by total reflection. The flat surfaces 71 to 73 are arranged across the step portion 8 in the light guiding direction D2, and play a role in dividing the incident light L2 into a plurality of pieces and reflecting them toward the smooth surface 2c side.

[0102] The first step portion 81 and the second step portion 82 are, for example, planar in shape and are inclined surfaces inclined at an inclination angle η relative to the thickness direction D1. The inclination angle η is preferably less than the light guide angle φ of the incident light L2, that is, η≤φ is satisfied, so as to prevent the first step portion 81 and the second step portion 82 from becoming obstacles when the incident light L2 is incident on the second flat surface 72 and the third flat surface 73.

[0103] In addition, as for the parts other than the flat surfaces 71 to 73 and the steps 81 and 82 in the refractive index difference layer 7, their shapes, sizes, etc. are arbitrary as long as they do not hinder the light of the incident light L2 that is directed toward the output surface 3a of the prism portion 3. In addition, the light guide angle of the incident light L2 is set to φ, and the refractive index difference layer 7 is configured, for example, so as not to be located on an imaginary straight line that passes through the output surface 3a of the prism portion 3 and has an angle of φ relative to the thickness direction D1. In addition, the refractive index difference layer 7 is configured at a position that is a distance less than a specified distance from the flat portion 6 in the thickness direction D1 to prevent accidental reflection in the light guide 2 or hinder the reflected light L21 to L23 generated by other refractive index difference layers 7. Furthermore, the refractive index difference layer 7 has, for example, the number of steps set to k (k is an integer greater than 1) and the number of flat surfaces set to k+1, where k is arbitrary.

[0104] Here, for example Fig.10 As shown, the pitch interval of the reflected lights L21 and L22 is set to P21 and the pitch interval of the reflected lights L22 and L23 is set to P22. In addition, the pitch interval between the third reflected light L23 and the first reflected light L21 of the refractive index difference layer 7 adjacent to the refractive index difference layer 7 generating the third reflected light L23 is set to P23. At this time, when the pitch interval of the adjacent refractive index difference layer 7 in the light guiding direction D2 is set to P2, the pitch intervals P21 to P23 are all less than half of P2. As a result, the optical component 1 is in a state where the pitch intervals P21 to P23 when the reflected lights L21 to L23 reach the second area 2bb are greatly different from the prism pitch PP2, and the effect of reducing moiré fringes can be obtained.

[0105] In addition, if Fig. 9 As shown, the widths of the reflected light L21-L23 in the light guiding direction D2 are set to S21, S22, and S23, respectively. Fig.10 As shown, the widths of the step portions 81 and 82 in the thickness direction D1 are respectively set to D41 and D42. At this time, the pitch intervals P21 and P22 are expressed by the following equations (5) and (6) in the first region 2ba.

[0106] P21=S21+2×D41×tanφ··· (5)

[0107] P22=S22+2×D42×tanφ··· (6)

[0108] The pitch intervals P21 to P23 do not need to be substantially the same, but when they are substantially the same, an effect of making the light amount of the emitted light L3 substantially uniform can be obtained.

[0109] According to this embodiment, the optical member 1 can also obtain the same effect as the first embodiment. In addition, since the optical member 1 of this embodiment has a refractive index difference layer 7 inside the light guide 2 and the flat surfaces 71 to 73 of the refractive index difference layer 7 function as a reflection surface in the first region 2ba, the flat portion 6 of the first region 2ba can be covered with a light shielding film (not shown). Therefore, the optical member 1 of this embodiment can also obtain the effect of reducing the influence caused by the invasion of external light from the emission portion 2b in the first region 2ba.

[0110] (Variation of the Second Embodiment)

[0111] The optical member 1 is, for example, Fig.11 As shown, the light guide 2 may include a base 21 and a prism sheet 22 , and the base 21 and the prism sheet 22 are bonded together by a transparent adhesive layer 23 .

[0112] The base 21, for example, includes a portion of the incident surface 2a, a smooth surface 2c, an inclined surface 2d, a portion of the terminal surface 2e, and a hollow portion 211 constituting the refractive index difference layer 7. The prism sheet 22, for example, includes the remaining portion of the incident surface 2a, the emitting portion 2b, the remaining portion of the terminal surface 2e, and a flat portion 221 opposite to the base 21, and the flat portion 221 is bonded to the base 21 via a transparent adhesive layer 23. The base 21 and the prism sheet 22 are formed independently of each other by, for example, any resin molding method using a mold not shown. The transparent adhesive layer 23 is composed of, for example, an optical adhesive such as OCA and OCR, and is set to have the same refractive index as the constituent material of the base 21 and the prism sheet 22. In addition, OCA and OCR are abbreviations for Optical Clear Adhesive and Optical Clear Resin, respectively. In this case, the refractive index difference layer 7 is constituted by, for example, an air layer existing in the cavity 211 , but may be constituted by filling the cavity 211 with a material having a lower refractive index than the base 21 .

[0113] According to this modification, the optical member 1 can also obtain the same effects as those of the second embodiment. In addition, by configuring the light guide 2 with a plurality of members, the effect of easy manufacturing can also be obtained.

[0114] (Third Embodiment)

[0115] Reference Figure 12 to Figure 15 An optical member 1 according to a third embodiment will be described.

[0116] exist Fig.14 , Fig.15 In, due to Figure 3For the same purpose, although the cross section is not shown, the incident light L2 and the reflected light L21 to L23 in the optical member 1 are shaded and the traveling directions of these lights are indicated by hollow arrows.

[0117] The optical member 1 of this embodiment is, for example, Fig.12 The embodiment shown in the figure is different from the first embodiment described above in the following aspects: the first area 2ba of the emission portion 2b is formed by repeatedly arranging a plurality of protrusions 9 having an emission surface 9a, and a refractive index difference layer 7 is formed inside the light guide 2 and inside the protrusions 9. In this embodiment, this difference is mainly described. In addition, the structure of the refractive index difference layer 7 is basically the same as that of the second embodiment described above, so in this embodiment, the difference is mainly described.

[0118] In the present embodiment, the refractive index difference layer 7 is partially or entirely formed in the protrusion 9, for example. The refractive index difference layer 7 has, for example, flat surfaces 71 to 73 and step portions 81 and 82, and is formed in such a way that the first flat surface 71 is at the same height position as the flat portion 6 of the second region 2bb. The refractive index difference layer 7 is, for example, configured such that the flat surface closer to the end surface 2e among the flat surfaces 71 to 73 is positioned lower, that is, closer to the emission portion 2b. The light guide angle of the incident light L2 is φ, and the refractive index difference layer 7 is, for example, configured so as not to be located on an imaginary straight line that passes through the emission surface 9a of the protrusion 9 and is inclined at an angle φ relative to the thickness direction D1.

[0119] The protrusion 9 is, for example, Fig.12 As shown, the shape of the projection 9 is a trapezoid, and the inclined surface on the end surface 2e side is an emission surface 9a parallel to the incident surface 2a. The plurality of projections 9 are repeatedly arranged along the light guide direction D2 in the first region 2ba and are arranged parallel to each other.

[0120] In addition, the plurality of protrusions 9 may be in any shape as long as they have an emission surface 9a and do not obstruct the emission light L3 from the emission surface 9a of the adjacent protrusion 9, and are not limited to a trapezoidal shape, and the shape of the portion other than the emission surface 9a is arbitrary. In addition, the plurality of protrusions 9 may also be covered with a light shielding film (not shown) other than the emission surface 9a in order to prevent external light from the emission portion 2b side from intruding into the light guide 2.

[0121] In this embodiment, for example, Fig.13 , Fig.14As shown, the optical member 1 uses the plurality of flat surfaces 71 to 73 of the refractive index difference layer 7 in the first region 2ba to split a portion of the incident light L2 from the incident surface 2a for reflection, and emits the remaining portion to the outside from the emission surface 9a of the protrusion 9. In the first region 2ba, a portion of the incident light L2 is split by the flat surfaces 71 to 73 into the first reflected light L21, the second reflected light L22, and the third reflected light L23, and is reflected toward the smooth surface 2c. In addition, in the second region 2bb and the third region 2bc, the optical member 1 reflects a portion of the incident light L2 using the smooth surface 2c and the flat portion 6, and emits the remaining portion to the outside from the prism portion 3, as in the first embodiment described above.

[0122] In addition, in this embodiment, if Fig.15 As shown, the spacing intervals P21 to P23 of the reflected lights L21 to L23 in the light guiding direction D2 do not need to be substantially the same as in the above-mentioned second embodiment. From the viewpoint of making the light amount of the emitted light L3 at the emission portion 2b substantially uniform, it is preferably substantially the same. In this case, the widths S21 to S23 of the reflected lights L21 to L23 in the light guiding direction D2, the inclination angle η of the step portions 81 and 82, the widths D41 and D42 in the thickness direction D1, and the spacing interval P2 of the refractive index difference layer 7 in the light guiding direction D2 are set to the same design as in the above-mentioned second embodiment.

[0123] According to this embodiment, the optical member 1 can obtain the same effects as those of the second embodiment. In addition, by providing a plurality of protrusions 9 with high freedom of shape and structure of portions other than the emission surface 9a, it is also possible to expect an effect of reducing manufacturing costs compared to the second embodiment.

[0124] (Fourth Embodiment)

[0125] Reference Figure 16 to Figure 19 An optical member 1 according to a fourth embodiment will be described.

[0126] exist Fig.18 , Fig.19 In, due to Figure 3 For the same purpose, although the cross section is not shown, the incident light L2 and the reflected light L21 to L23 in the optical member 1 are shaded and the traveling directions of these lights are indicated by hollow arrows.

[0127] The optical member 1 of this embodiment is, for example, Fig.16 The embodiment shown in the figure is different from the first embodiment described above in that the first region 2ba of the emission portion 2b is configured to have the same structure as the second region 2bb, and a split reflection portion 2f composed of a stepped reflection surface 10 is provided between the smooth surface 2c and the inclined surface 2d. In the present embodiment, this difference will be mainly described.

[0128] The emission portion 2b in this embodiment is similar to the above-mentioned second embodiment in that it is formed by alternately arranging the prism portion 3 and the flat portion 6, and the prism pitch PP1 is larger than that of the second region 2bb. Fig.17 The structure shown in the figure is that the flat portion 6 reflects a part of the incident light L2 toward the split reflection portion 2f, and the prism portion 3 emits the rest of the incident light L2 to the outside.

[0129] The split reflector 2f is formed by repeatedly arranging a plurality of stepped reflective surfaces 10 along the light guiding direction D2. Fig.18 The incident light L2 is split by the multiple reflection surfaces 11 to 13 of the stepped reflection surface 10, and the reflected lights L21 to L23 are reflected toward the second region 2bb of the emission portion 2b. The width of the split reflection portion 2f in the light guiding direction D2 is smaller than the width of the first region 2ba in the same direction.

[0130] The stepped reflecting surface 10 is formed, for example, by having a first reflecting surface 11, a second reflecting surface 12, and a third reflecting surface 13 that are substantially parallel to the flat portion 6, and a step portion 14 that connects adjacent reflecting surfaces. In the stepped reflecting surface 10, the height positions of the first reflecting surface 11, the second reflecting surface 12, and the third reflecting surface 13 are different from each other. The reflecting surfaces 11 to 13 are configured, for example, in such a manner that the closer the reflecting surface is to the end surface 2e side, the higher its height position is, that is, the farther away from the light guide 2. For example, the reflecting surfaces 11 to 13 are configured as follows: the first reflecting surface 11 is set at the same height position as the smooth surface 2c, the second reflecting surface 12 protrudes from the first reflecting surface 11 and the smooth surface 2c, and the third reflecting surface 13 is at a position that protrudes further from the smooth surface 2c than the second reflecting surface 12. In addition, the stepped reflecting surface 10 is, for example, Fig.19 The structure shown is such that the inclination angle η of the planar step portion 14 relative to the thickness direction D1 is less than the light guide angle φ of the incident light L2. Therefore, with respect to the stepped reflective surface 10, a part of the incident light L2 reflected in the first area 2ba is not blocked by the step portion 14, and can be reflected by the first reflective surface 11, the second reflective surface 12, and the third reflective surface 13 without waste, thereby suppressing the loss of light.

[0131] The step portion 14 is not limited to a planar shape as long as it does not obstruct the light of the incident light L2 directed toward the second reflecting surface 12 and the third reflecting surface 13 , and may be other shapes such as a curved shape or a composite shape having a planar portion and a curved portion.

[0132] Here, if Fig.18As shown, the reflected light on the reflection surfaces 11 to 13 is set to the first reflected light L21, the second reflected light L22, and the third reflected light L23, respectively, and the spacing intervals of the reflected lights L21 to L23 in the light guiding direction D2 are set to P31, P32, and P33, respectively. In addition, the spacing intervals P31 and P32 are the spacing intervals between the first reflected light L21 and the second reflected light L22, and the spacing intervals between the second reflected light L22 and the third reflected light L23, respectively. In addition, the spacing interval P33 is the spacing interval between the third reflected light L23 and the first reflected light L21 generated by the stepped reflection surface 10 adjacent to the stepped reflection surface 10 generating the third reflected light L23.

[0133] At this time, the stepped reflective surface 10 is configured so that when the pitch interval in the light guide direction D2 of the adjacent stepped reflective surfaces 10 is set to P3, the pitch intervals P31 to P33 are respectively less than half of the pitch interval P3. In addition, the stepped reflective surface 10 is set so that the pitch interval P3 is less than the prism pitch PP1 of the first area 2ba, and the stepped reflective surface 10 is set to the same number as the number of flat portions 6 in the first area 2ba. Thus, the optical member 1 of the present embodiment causes all the incident light L2 reflected in the first area 2ba to be incident on the split reflection portion 2f and is split into reflected light L21 to L23 of the pitch intervals P31 to P33 that are significantly different from the prism pitch PP2 of the second area 2bb. Therefore, the optical member 1 has a structure that can reduce moire fringes in the second area 2bb.

[0134] In addition, the pitch intervals P31 to P33 of the reflected lights L21 to L23 do not need to be substantially the same, but are preferably substantially the same from the viewpoint of making the light amount of the emitted light L3 at the emission portion 2b substantially uniform. In this case, the widths S31 to S33 of the reflected lights L21 to L23 in the light guide direction D2, the inclination angle η of the step portion 14, and the widths D51 and D52 in the thickness direction D1 are designed the same as those in the second embodiment described above.

[0135] According to this embodiment, the optical component 1 can also obtain the same effect as the first embodiment. In addition, since the optical component 1 does not have a step portion with an inclination angle η in the first area 2ba of the emitting portion 2b, it can also obtain the effect of suppressing the external light on the emitting portion 2b side from being incident on the inside of the light guide 2 to reduce the generation of ghosting.

[0136] (Other Embodiments)

[0137] The present disclosure is described based on the embodiments, but it should be understood that the present disclosure is not limited to these embodiments and structures. The present disclosure also includes various modifications and modifications within the equivalent range. In addition, various combinations and forms, and other combinations and forms of only one element, the above elements or the following elements also fall within the scope and thought of the present disclosure.

[0138] (1) The optical member 1 is, for example, Fig. 20 As shown, the configuration and structure of the incident surface 2a can also be changed. Specifically, the incident surface 2a can be configured in a manner adjacent to the smooth surface 2c and opposite to the emitting portion 2b together with the smooth surface 2c. In the optical component 1, the incident surface 2a and the smooth surface 2c are opposite to the emitting portion 2b in approximately parallel, and the optical component 1 also has an incident side surface 2g located on the opposite side of the end surface 2e and connecting the incident surface 2a and the emitting portion 2b. In this case, the incident surface 2a protrudes more than the smooth surface 2c, for example, and is formed by having a plurality of protruding incident prism portions 15 that are triangular in shape when observed in cross-section. Furthermore, the incident surface 2a is composed only of a plurality of incident prism portions 15, and the plurality of incident prism portions 15 are repeatedly arranged along the light guiding direction D2. The incident side surface 2g only needs to not prevent the incident light L2 from the incident surface 2a from entering the emission portion 2b, and the surface shape and inclination can be appropriately changed, and can also be covered with a light-shielding film (not shown) to prevent accidental incidence of external light.

[0139] For example Fig.21 As shown, the surface of the incident prism section 15 on the opposite side to the end face 2e becomes the incident section 15a parallel to the emission face 3a of the prism section 3. The surface of the incident prism section 15 on the end face 2e side adjacent to the incident section 15a becomes the adjacent surface 15b having an inclination angle α with respect to the thickness direction D1. The incident prism section 15 is designed, for example, so that when the inclination angle of the external scene light L1 incident on the incident section 15a is set to θ and the inclination angle of the incident section 15a with respect to the thickness direction D1 is set to ψ, the inclination angle α of the adjacent surface 15b satisfies θ<α<ψ. As a result, the external scene light L1 is not blocked by the adjacent surface 15b and is incident on the incident section 15a, and the occurrence of gaps in the incident light L2 between the incident prism sections 15 can be suppressed, thereby forming the incident surface 2a that can reduce the loss of light.

[0140] Furthermore, the above-described modified examples of the optical member 1 are examples of application to the above-described first embodiment, but are not limited thereto and may be applied to embodiments other than the above-described first embodiment and their modified examples.

[0141] (2) For example Fig. 22As shown, the optical component 1 may also have the emission portion 2b configured as the same structure as the second embodiment described above and the arrangement of the plurality of refractive index difference layers 7 inside the light guide 2 may be changed to be near the smooth surface 2c. In this case, the refractive index difference layer 7 is arranged near the surface on the side of the inclined surface 2d in the smooth surface 2c and is arranged in a predetermined area for the incident light L2 reflected by the first area 2ba to be incident. The refractive index difference layer 7 is arranged, for example, in the order of the first flat surface 71, the second flat surface 72, and the third flat surface 73 from the side of the incident surface 2a toward the end surface 2e, and is arranged in such a manner that the flat surface on the side of the end surface 2e has a higher height position, that is, is closer to the smooth surface 2c. In addition, the refractive index difference layer 7 may be arranged in plurality or may be configured as a single layer formed by repeatedly arranging the first flat surface 71, the second flat surface 72, and the third flat surface 73 in this order.

[0142] According to this variation, the optical component 1 can obtain the effect of reducing moiré fringes in the same manner as the first embodiment described above. That is, the optical component 1 can be configured to be capable of dividing the incident light L2 into a plurality of reflected lights having a pitch interval significantly different from the prism pitch PP2 of the second region 2bb at any position from the first region 2ba of the emission portion 2b to the second region 2bb.

[0143] (3) In addition, in the above-mentioned embodiments, the elements constituting the embodiments are not necessarily essential elements, except for the cases where they are specifically stated to be essential or the cases where they are obviously essential in principle. In addition, in the above-mentioned embodiments, when referring to the number, value, amount, range, etc. of the constituent elements of the embodiments, they are not limited to the specific numbers, except for the cases where they are specifically stated to be essential or the cases where they are obviously limited to the specific numbers in principle. In addition, in the above-mentioned embodiments, when referring to the shapes, positional relationships, etc. of the constituent elements, etc., they are not limited to the shapes, positional relationships, etc., except for the cases where they are specifically stated to be essential or the cases where they are obviously limited to the specific shapes, positional relationships, etc. in principle.

Claims

1. An optical member that guides external scene light by reflecting it internally, characterized in that: The optical member includes a light guide body made of a light-transmitting material, the light guide body including an incident surface for the external scene light to be incident, an emission portion for emitting a part of the light incident from the incident surface to the outside, a smooth surface opposite to the emission portion, and a terminal surface located on the side opposite to the incident surface and connecting the emission portion and the smooth surface. The emitting portion includes a first region adjacent to the incident surface and a second region adjacent to the first region. The first region has a plurality of stepped reflecting surfaces and a plurality of protruding prism portions, and the stepped reflecting surfaces and the prism portions are arranged alternately and repeatedly, and the stepped reflecting surface has a plurality of flat surfaces located at different heights across the step portions and facing the surface formed by the smooth surface, The second region has a plurality of the prism portions and a plurality of flat portions as one flat surface, and is formed by repeatedly arranging the prism portions and the flat portions alternately. The flat surface, the flat portion, and the smooth surface reflect a portion of the incident light entering the interior of the light guide from the incident surface by total reflection. The prism portion includes an emission surface that emits a portion of the incident light to the outside.

2. The optical component according to claim 1, wherein The direction connecting the flat portion and the smooth surface along the normal direction with respect to the flat portion is defined as a thickness direction, the direction from the smooth surface toward the flat portion in the thickness direction is defined as a bottom, and the positions of the plurality of flat surfaces in the thickness direction are defined as height positions, The stepped reflecting surface is provided so that the height position of the flat surface, which is closer to the terminal surface among the plurality of flat surfaces, becomes lower.

3. The optical component according to claim 1 or 2, characterized in that: On the plane formed by the flat portion, a direction from the incident surface toward the terminal surface along the arrangement direction of the flat portion and the prism portion is set as a light guiding direction, The width of each of the plurality of flat surfaces in the first region in the light guiding direction is equal to or smaller than half of the pitch interval between adjacent prism portions.

4. An optical member that guides external scene light by reflecting it internally, characterized in that: The optical component comprises: a light guide body made of a light-transmitting material, comprising an incident surface for the external scene light to be incident on, an emission portion having a plurality of protruding prism portions and a plurality of flat portions as flat surfaces and emitting a portion of the light incident from the incident surface to the outside, a smooth surface opposite to the emission portion, and a terminal surface located on the side opposite to the incident surface and connecting the emission portion to the smooth surface; and A plurality of refractive index difference layers are arranged in the vicinity of the emission portion inside the light guide and in a region where incident light incident from at least the incident surface directly enters, and have a plurality of flat surfaces arranged at different heights with a step portion therebetween and facing the plane formed by the smooth surface, wherein the refractive index of the plurality of refractive index difference layers is lower than that of the light guide, The flat surface, the flat portion, and the smooth surface reflect a portion of the incident light by total reflection, The prism portion has an emission surface for emitting a part of the incident light to the outside. The plurality of refractive index difference layers are arranged at a distance from each other so as not to shield light incident on the emission surface among the incident light.

5. The optical component according to claim 4, characterized in that The direction connecting the flat portion and the smooth surface along the normal direction with respect to the flat portion is defined as a thickness direction, the direction from the smooth surface toward the flat portion in the thickness direction is defined as a bottom, and the positions of the plurality of flat surfaces in the thickness direction are defined as height positions, The refractive index difference layer is provided so that the height position of the flat surface, among the plurality of flat surfaces, becomes lower as the flat surface becomes closer to the end surface.

6. The optical component according to claim 4, characterized in that On the plane formed by the flat portion, a direction from the incident surface toward the terminal surface along the arrangement direction of the flat portion and the prism portion is set as a light guiding direction, The width of each of the plurality of flat surfaces in the refractive index difference layer in the light guiding direction is less than or equal to half of a pitch between adjacent refractive index difference layers.

7. The optical component according to any one of claims 4 to 6, characterized in that The refractive index difference layer is an air layer.

8. An optical member that guides external scene light by reflecting it internally, characterized in that: The optical member includes a light guide body made of a light-transmitting material, the light guide body including an incident surface for the external scene light to be incident, an emission portion having a plurality of protruding prism portions and a plurality of flat portions as flat surfaces and emitting a portion of the light incident from the incident surface to the outside, a split reflection portion and a smooth surface opposite to the emission portion, and a terminal surface located on the side opposite to the incident surface and connecting the emission portion and the smooth surface. The split reflection portion is adjacent to the smooth surface and is located closer to the incident surface than the smooth surface, and the split reflection portion is formed by repeatedly arranging a plurality of stepped reflection surfaces, wherein a plurality of reflection surfaces facing the surface formed by the plurality of flat portions in the stepped reflection surface are located at different heights from each other via the step portions. The reflecting surface, the flat portion, and the smooth surface reflect a portion of the incident light entering the interior of the light guide from the incident surface by total reflection. The prism portion includes an emission surface that emits a portion of the incident light to the outside.

9. The optical component according to claim 8, wherein: The direction connecting the flat portion and the smooth surface along the normal direction with respect to the flat portion is defined as a thickness direction, the direction from the flat portion toward the smooth surface in the thickness direction is defined as an upper direction, and the positions of the plurality of reflection surfaces in the thickness direction are defined as height positions, The stepped reflecting surface is arranged so that, among the plurality of reflecting surfaces, the closer the reflecting surface is to the terminal surface, the higher the height position is.

10. The optical component according to claim 8, wherein On the plane formed by the flat portion, a direction from the incident surface toward the terminal surface along the arrangement direction of the flat portion and the prism portion is set as a light guiding direction, The width of each of the plurality of reflective surfaces in the stepped reflective surface in the light guiding direction is less than or equal to half of the pitch between adjacent stepped reflective surfaces.

11. The optical component according to any one of claims 8 to 10, characterized in that On the plane formed by the flat portion, a direction from the incident surface toward the terminal surface along the arrangement direction of the flat portion and the prism portion is set as a light guiding direction, The width of the divided reflection portion in the light guiding direction is equal to or smaller than the width of a region of the emission portion on which the incident light from the incident surface directly enters the light guiding direction.

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