Dead Angle Assist Device

Abstract

To suppress the relative positional deviation of portions that function as a pair of mirrors in an optical member and suppress superimposition of other light on emission light in a dead angle auxiliary device.SOLUTION: An optical member comprises: an incidence surface 2a on which ambient light is incident; an emission surface 2b which has a plurality of emission parts 21 and flat parts 22; and a smooth surface 2c which is arranged so as to be opposed to the plurality of flat parts 22. The optical member 2 is made of a translucent material and reflects incident light by total reflection on the flat parts 22 and the smooth surface 2c. The optical member 2 is attached to a storage part of a holding member 3 and is fixed in such a state that there is a prescribed or greater gap between the smooth surface 2c and a bottom surface 31a of the storage part. A light shielding member 4 is arranged on an end on at least the incidence surface 2a side of the gap between the surface on the smooth surface 2c side of the optical member 2 and the holding member 3.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a blind spot assisting device using an optical member that reflects part of the incident light inside and emits the incident light and its reflected light to the outside from a surface different from the incident surface.

Background Art

[0002] Conventionally, examples of this type of optical member include those described in Patent Document 1. The optical member described in Patent Document 1 is attached to a pillar of a vehicle and used as part of a blind spot assisting device. This optical member includes a half mirror that reflects part of the outside scene light and transmits part of it, a mirror that reflects the reflected light at the half mirror back to the half mirror, and a case body that holds these in a facing arrangement, and the case body is attached to the vehicle pillar.

[0003] When outside scene light from the opposite side across the vehicle pillar is incident, this optical member is configured to repeatedly reflect between a pair of mirrors composed of the mirror and the half mirror, and transmit through the half mirror arranged on the side opposite to the vehicle pillar. As a result, it becomes a blind spot assisting device that allows the outside scene of the blind spot area hidden by the vehicle pillar to be visually recognized through the optical member.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, since the mirror and the half mirror of this optical member are separate members, if their relative positions shift, the position of the external scene due to the light transmitted through the half mirror, that is, the position of the external scene that the user visually recognizes through the optical member, will deviate from the actual situation. In order to prevent such a situation, a housing for holding the relative positions of the pair of mirrors so that they do not shift, and a fixing member for fixing the housing and the pair of mirrors are required. In addition, the configuration for suppressing the deviation of the relative positions of the pair of mirrors increases the number of parts, and the assembly to other members such as vehicle pillars is also complicated and requires high precision.

[0006] As a result of intensive studies, the inventors of the present invention newly devised an optical member made of a light guiding material and capable of internally guiding the incident external scene light by using total reflection, and this optical member is composed of a single member. Thus, a new blind spot assisting device has been developed in which this optical member is held and fixed to other members such as vehicle pillars. Since this new blind spot assisting device has an optical member that is a single member without two separate mirrors, the deviation of the relative positions of the pair of mirrors does not occur, and the deviation between the position of the external scene caused by this and the actual scene is suppressed.

[0007] Since this new blind spot assisting device has an optical member configured to use total reflection, it is necessary to provide a predetermined gap between the holding member and the light reflecting surface. However, as a result of further studies by the inventors of the present invention, it has been found that unintended light is superimposed on the light emitted to the outside from the emission surface of the optical member when external scene light enters the gap between the optical member and the holding member.

[0008] In view of the above points, the present invention aims to suppress the superimposition of unintended light in a blind spot assisting device using an optical member in which no relative position deviation occurs between two surfaces, namely, an emission surface that causes reflection and transmission of incident external scene light and a reflection surface that reflects the incident external scene light to the emission surface.

Means for Solving the Problems

[0009] To achieve the above object, the blind spot assisting device according to claim 1 has an incident surface (2a, 23a) on which external scene light is incident, a plurality of emission portions (21) and a plurality of flat portions (22), an emission surface (2b) on which the incident light incident from the incident surface first arrives, and a smooth surface (2c) disposed opposite to the plurality of flat portions. It includes an optical member (2) made of a light-transmissive material, a housing portion (31) that houses the optical member, a holding member (3) that holds the optical member, and a light-shielding member (4) disposed at least at the end on the incident surface side of the gap between the smooth surface of the optical member and the bottom surface of the housing portion with the surface of the housing portion facing the smooth surface of the optical member as the bottom surface (31a). The plurality of flat portions are first reflecting surfaces that reflect incident light toward the smooth surface by total reflection, the smooth surface is a second reflecting surface that reflects the reflected light reflected by the flat portions toward the emission surface by total reflection, and the plurality of emission portions emit a part of the incident light or a part of the light reflected by the smooth surface to the outside opposite to the holding member.

[0010] In this blind spot assisting device, an optical member which is a single member made of a light-transmissive material is used. A part of the external scene light incident from the incident surface of the optical member is reflected by total reflection at the flat portions and the smooth surface, and a part of the incident external scene light is emitted to the outside from the emission portions. In this blind spot assisting device, since there is no relative positional deviation between the flat portion and the smooth surface that function as a pair of mirrors in the optical member, the number of constituent members is less than before, and the optical member can be easily and simply assembled to the holding member. Further, a light-shielding member is disposed at the end on the incident surface side of the gap between the smooth surface of the optical member and the bottom surface of the housing portion of the holding member, and the intrusion of light from the incident surface side is prevented. Therefore, unnecessary external scene light does not enter the smooth surface, and unintended external scene light does not overlap with the emitted light from the emission surface.

[0011] Note that the reference numerals in parentheses attached to each component etc. show an example of the correspondence relationship between the component etc. and the specific components etc. described in the embodiments described later.

Brief Description of the Drawings

[0012]

Figure 1

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Embodiments for Carrying Out the Invention

[0013] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each of the following embodiments, parts that are the same or equivalent to each other will be described with the same reference numerals.

[0014] (First Embodiment) The blind spot assisting device 1 of the first embodiment will be described with reference to the drawings.

[0015] In FIGS. 1 and 2, a part of the outer contour of the holding member 3 that cannot be seen later is shown by a broken line. Hereinafter, for convenience of explanation, as shown in FIG. 1, the direction along the light guiding direction described later in the optical member 2 of the holding member 3 is referred to as the "first direction D1", and the direction along the direction connecting the upper surface 2e and the lower surface 2f of the optical member 2 described later is referred to as the "second direction D2". D1 and D2 shown in the figures after FIG. 2 are directions corresponding to D1 and D2 shown in FIG. 1.

[0016] The blind spot assisting device 1 of the present embodiment includes, for example, as shown in FIGS. 1 and 2, an optical member 2, a holding member 3 having a housing portion 31, and a light shielding member 4. The blind spot assisting device 1 is configured such that, for example, as shown in FIGS. 3 and 4, the optical member 2 is attached to the housing portion 31 of the holding member 3, and the light shielding member 4 is disposed at one end of the gap between the optical member 2 and the holding member 3. The blind spot assisting device 1 is configured to make the blind spot region visible by guiding the external scene light from the region that becomes a blind spot by the holding member 3 inside the optical member 2 and emitting it to the user side. The blind spot assisting device 1 is preferably applied, for example, to an in-vehicle use in which the holding member 3 is a pillar that obstructs the driver's field of view in a vehicle such as an automobile, and the driver and the like can visually recognize the blind spot region. Of course, it can also be applied to blind spot assistance in other uses. In this specification, the case where the blind spot assisting device 1 is used for in-vehicle applications will be described as a representative example.

[0017] As shown in FIG. 5 for example, the optical member 2 is a light guide having an incident surface 2a, a smooth surface 2c adjacent to the incident surface 2a, an emission surface 2b facing the smooth surface 2c, and a terminal surface 2d facing the incident surface 2a. The optical member 2 has an upper surface 2e and a lower surface 2f, which are surfaces connecting the emission surface 2b and the smooth surface 2c and also surfaces connecting the incident surface 2a and the terminal surface 2d. The optical member 2 is a single member whose base is made of a translucent material. In a situation where there is no incident light on the incident surface 2a, when the user views the optical member 2 alone from the emission surface 2b side, it is a light guide that allows the user to visually recognize the scene on the smooth surface 2c side. As the translucent material, for example, resin materials such as polyethylene terephthalate, polycarbonate, polyethylene, and acrylic, or inorganic materials such as glass can be used. The optical member 2 does not have a mirror and a half mirror made of a reflective material with a reflectivity of a predetermined value or more, and is designed to guide light by totally reflecting incident light on the surface made of the translucent material. Note that in this embodiment, the base of the optical member 2 means the portion excluding the light absorption film 211 described later.

[0018] In this embodiment, as shown in FIG. 4 for example, the optical member 2 is fixed to the holding member 3 by being fitted into the housing portion 31 of the holding member 3. The optical member 2 is held by the holding member 3 in a state where the smooth surface 2c faces the housing portion 31 and the emission surface 2b faces in a direction opposite to the holding member 3. The optical member 2 is fixed in a state where a gap D0 of a predetermined value or more (for example, although not limited, 1 mm or more) is formed between the smooth surface 2c and the bottom surface 31a of the housing portion 31, and the total reflection state on the smooth surface 2c can be ensured. The optical member 2 is attached to the holding member 3 such that the incident surface 2a and the terminal surface 2d are respectively located near the ends in the first direction D1 of the bottom surface 31a of the housing portion 31.

[0019] As shown in, for example, FIG. 6, the optical member 2 has an emission surface 2b having a plurality of emission portions 21 and flat portions 22, which are alternately and repeatedly arranged. As shown in, for example, FIG. 7, the optical member 2 allows external scene light to enter from the incident surface 2a, repeatedly reflects the incident light by the emission surface 2b and the smooth surface 2c, and emits a part of the light from the emission surface 2b to the outside, thereby allowing a user on the emission surface 2b side to visually recognize the external scene.

[0020] Hereinafter, for convenience of explanation, as shown in, for example, FIG. 7, the light from the outside to the incident surface 2a of the optical member 2 may be referred to as "external scene light L1", and the light that has entered the inside of the optical member 2 from the incident surface 2a among the external scene light L1 may be referred to as "incident light L2", respectively. Also, the light that is emitted from the emission surface 2b to the outside of the optical member 2 among the incident light L2 may be referred to as "emitted light L3".

[0021] As shown in, for example, FIG. 7, the optical member 2 is made of a light-transmissive material and is designed to satisfy the following formula (1) in order to totally reflect the incident light L2 at the flat portion 22 and the smooth surface 2c of the emission surface 2b.

[0022] sinφ≧n2 / n1···(1) In formula (1), n1 is the refractive index of the optical member 2, and n2 is the refractive index of the external medium (for example, air). Also, φ is the incident angle of the incident light L2 to the flat portion 22, which is the angle formed by the normal direction (hereinafter simply referred to as the "normal direction") to the plane formed by the flat portion 22 or the smooth surface 2c and the traveling direction of the incident light L2. Thereby, the optical member 2 is configured such that a part of the incident light L2 from the incident surface 2a is totally reflected by the flat portion 22 and the smooth surface 2c and is emitted to the outside from the emission surface 2b without having a semi-transmissive mirror and a mirror made of a reflective material such as metal. Note that it is preferable that the inclination angle ψ formed by the incident surface 2a with respect to the normal direction is smaller than the incident angle φ of the incident light L2, that is, the light guiding angle. Also, θ1 in FIG. 7 is the incident angle of the external scene light L1, which is the angle formed by the traveling direction of the external scene light L1 and the normal direction.

[0023] The emitting surface 2b is the surface where the incident light L2 from the incident surface 2a first arrives. The emitting surface 2b is, for example, a triangular protrusion in cross-section view, and a plurality of emission portions 21 that are similar to each other are arranged in parallel with a flat portion 22 therebetween. Among the emitting surface 2b, the emission portions 21 are sites that emit the incident light L2 to the outside. Among the emitting surface 2b, the flat portion 22 is a first reflecting surface that reflects the incident light L2 toward the smooth surface 2c by total reflection. Thereby, the optical member 2 can guide the incident light L2 inside without having a semi-transmissive mirror made of a metal material or a dielectric material, and is configured such that loss due to absorption of the incident light L2 does not occur in the flat portion 22.

[0024] Here, one virtual plane formed by a plurality of flat portions 22 is defined as a flat surface, the direction from the incident surface 2a toward the end surface 2d along the flat surface is defined as the light guiding direction, and the width in the light guiding direction is W 22 Let it be so. At this time, the plurality of flat portions 22 have a width W 22 such that the reflectance of the incident light L2 on the emitting surface 2b is equal to or greater than a predetermined value. W Specifically, since among the emitting surface 2b, the plurality of flat portions 22 are reflection portions of the incident light L2, and the plurality of emission portions 21 are absorption portions and emission portions of the incident light L2, the reflectance R W of the emitting surface 2b is determined by the ratio of the flat portion 22. The reflectance R W of the emitting surface 2b is 22 the width of the emission portion 21 adjacent to the flat portion 22 having the width W 21 in the light guiding direction, and is expressed by the following formula (2).

[0025] R W = W 22 / (W 21 + W 22 ) ··· (2) The plurality of flat portions 22 satisfy R W ≧ 0.5, that is, the width W 22 such that the reflection of the incident light L2 on the emitting surface 2b is equal to or greater than the emission, that is, W 21 / W 22It is preferably set to a width that satisfies ≤1. In this case, the optical member 2 guides more than half of the incident light L2 at the light-emitting surface 2b and emits the emitted light L3 over a wider range of the light-emitting surface 2b, making it possible to ensure the brightness of the emitted light L3.

[0026] Further, when the optical member 2 satisfies the above formula (1) and the incident angle φ is the total reflection angle, the reflectance R at the light-emitting surface 2b W is determined only by the ratio of the widths of the light-emitting portion 21 and the flat portion 22 as shown in the above formula (2). That is, for the optical member 2, the reflectance R of the optical member 2 W does not depend on the angle or wavelength of the incident light L2, so an effect of suppressing changes in the color tone and brightness of the emitted light L3 can be obtained compared to conventional optical members using semi-transparent mirrors.

[0027] As shown in FIG. 7, for example, the plurality of light-emitting portions 21 have a first surface 21a and a second surface 21b that faces the first surface 21a and intersects the first surface 21a. The first surface 21a is adjacent to the flat portion 22 and is a surface that emits a part of the incident light L2 to the outside. The first surface 21a is, for example, substantially parallel to the incident surface 2a. When the first surface 21a is parallel to the incident surface 2a, the emission angle θ2 of the emitted light L3 from the first surface 21a becomes the same as the incident angle θ1, so the optical member 2 can allow a user on the side of the light-emitting surface 2b to visually recognize the same light rays as the external scene light L1.

[0028] Note that the emission angle θ2 of the emitted light L3 is the angle formed by the traveling direction of the emitted light L3 and the normal direction. In addition to the case where the incident surface 2a and the first surface 21a are parallel, the term "substantially parallel" includes the case where the incident surface 2a and the first surface 21a are approximately parallel due to inevitable errors in relation to the processing accuracy of the optical member 2. The same meaning applies to "substantially parallel" in the following description of this specification.

[0029] Of the plurality of injection parts 21, the second surface 21b is inclined at an inclination angle δ with respect to the normal direction. The second surface 21b is preferably covered with a light absorption film 211 from the viewpoint of suppressing, for example, reflection of the incident light L2 on the second surface 21b and intrusion of external light from the side of the emission surface 2b. Thereby, it is possible to suppress ghost in which external light from the side of the emission surface 2b overlaps with the emitted light L3 and is visible, and noise caused by unintentional reflected light of the incident light L2 on the second surface 21b being emitted from the first surface 21a. The light absorption film 211 is formed of an arbitrary light-shielding resin material, metal material, etc., and is formed by an arbitrary process such as printing or vapor deposition.

[0030] The second surface 21b has an inclination angle δ that is equal to or greater than the emission angle θ2 of the emitted light L3 and, when the incident surface 2a and the first surface 21a are parallel, is equal to or greater than the incident angle θ1 of the external scene light L1. Thereby, the emitted light L3 is emitted to the outside without being blocked by the second surface 21b. Further, the second surface 21b preferably has an inclination angle δ that is smaller than the incident angle φ (light guiding angle) of the incident light L2 in the flat part 22. Thereby, the incident light L2 is suppressed from entering and interfering with the second surface 21b, and unintentional reflection of the incident light L2 on the second surface 21b and noise caused thereby can be suppressed.

[0031] Note that the width W of the plurality of injection parts 21 21 and the width W of the plurality of flat parts 22 22 If they are all the same, a gap of width W is formed in the reflected light beam, and uneven brightness, that is, moire, may occur due to the periodic change in the relationship between the gap and the subsequent injection part 21. From the viewpoint of suppressing such moire, W 21 and W 21 and W 22 are, for example, values within a predetermined range centered on a certain value, that is, preferably have a distribution.

[0032] The smooth surface 2c is a second reflecting surface that reflects the incident light L2 reflected by the flat portion 22 to the emitting surface 2b side by total reflection. In other words, the smooth surface 2c is substantially parallel to the flat portion 22 and functions as a pair of mirrors together with the flat portion 22. Therefore, the incident light L2 from the incident surface 2a is repeatedly incident and reflected at the incident angle φ at the flat portion 22 and the smooth surface 2c, and while traveling along the light guiding direction, it is emitted to the outside from the emitting portion 21 over the entire area of the emitting surface 2b. And the remainder of the incident light L2 is finally emitted to the outside from the end surface 2d.

[0033] The end surface 2d is a surface that connects the emitting surface 2b and the smooth surface 2c on the side opposite to the incident surface 2a, and is located at a position facing the incident surface 2a, that is, at the end in the light guiding direction. The end surface 2d is inclined to intersect the first surface 21a of the emitting portion 21 (hereinafter referred to as the "end emitting portion") located at the end opposite to the incident surface 2a among the plurality of emitting portions 21, as shown in FIG. 6, for example. Note that the end surface 2d is not limited to the configuration shown in FIG. 6, and may be configured to form one surface together with the first surface 21a of the end emitting portion 21, or the inclination may be adjusted so as to form a continuous curved surface with the holding member 3 described later. In the former case, the end surface 2d is substantially parallel to the incident surface 2a.

[0034] The upper surface 2e and the lower surface 2f are non-optical surfaces that are not used for reflecting the incident light L2. The optical member 2 has a width in the direction connecting the upper surface 2e and the lower surface 2f that is approximately the same as the width of the accommodating portion 31 of the holding member 3 in the second direction D2. The optical member 2 is configured such that the upper surface 2e and the lower surface 2f are fitted and fixed to the holding member 3.

[0035] The holding member 3 is a member to which the optical member 2 is attached. In the case of in-vehicle use, for example, it is a vehicle body pillar such as an A-pillar or a pillar cover that covers the vehicle body pillar. As shown in FIG. 2, for example, the holding member 3 has a housing portion 31 in which the optical member 2 is housed. When the optical member 2 is attached, the bottom surface 31a of the housing portion 31 faces the smooth surface 2c of the optical member 2, and the side wall surface 31b adjacent to the bottom surface 31a faces the upper surface 2e and the lower surface 2f of the optical member 2, respectively. A part of the side wall surface 31b protrudes outside the bottom surface 31a in the first direction D1. The protruding portion 31ba, which is the portion of the side wall surface 31b that protrudes outside the bottom surface 31a, covers a predetermined region on the incident surface 2a side of the upper surface 2e and the lower surface 2f of the optical member 2.

[0036] The light-shielding member 4 is disposed at least at the end on the incident surface 2a side in the gap between the optical member 2 and the holding member 3, and is a member for blocking a part of the gap to shield light. The light-shielding member 4 is composed of, for example, an elastic body such as rubber, resin, or silicon. Further, the light-shielding member 4 is a light absorber in which part or all is composed of a light-absorbing material. The width of the portion of the light-shielding member 4 in contact with the smooth surface 2c is preferably set to be equal to or less than a predetermined value (not limited, for example, 1 mm or less) so as to prevent total internal reflection inside the smooth surface 2c as much as possible.

[0037] The light-shielding member 4 is adhered to the optical member 2 by an optical adhesive (not shown) such as OCA or OCR, or adhered to the holding member 3 by an arbitrary adhesive, and is integrated with the optical member 2 or the holding member 3. OCA is an abbreviation for Optical Clear Adhesive, and OCR is an abbreviation for Optical Clear Resin. As shown in FIG. 3, for example, when the optical member 2 is attached to the housing portion 31 of the holding member 3, while ensuring a gap of a predetermined value or more between the smooth surface 2c and the bottom surface 31a of the housing portion 31, unintended light L from the incident surface 2a side 11prevents it from entering the smooth surface 2c. That is, in addition to light shielding, the light shielding member 4 also functions as a positioning member for the holding member 3. Thereby, while ensuring total internal reflection inside the smooth surface 2c, unintended light L 11 is prevented from overlapping with the emitted light L3 emitted from the emission surface 2b and interfering with the external scene visibility.

[0038] Specifically, for example, as shown in FIG. 8, in the case of the dead angle assisting device 100 of the comparative example without the light shielding member 4, the optical member 2 has external scene light L1 incident on the incident surface 2a, and unintended light L 11 also enters the gap with the holding member 3. Then, incident light L2 and the incident unintended light L 11 enter the inside of the optical member 2, and these lights are emitted from the first surface 21a of the emission part 21. As a result, the emitted light L3 and the unintended light L 11 overlap from the emission surface 2b, and the external scene visibility at the emission surface 2b is hindered. Thus, although the dead angle assisting device 100 of the comparative example has a new configuration using the optical member 2 composed of a single member, the external scene visibility at the emission surface 2b may be hindered due to the above-described light overlap.

[0039] On the other hand, in the dead angle assisting device 1 of the present embodiment, since the light shielding member 4 is disposed at the end on the incident surface 2a side of the gap between the optical member 2 and the holding member 3, unintended light L 11 from the outside on the incident surface 2a side does not enter the smooth surface 2c. Thereby, the overlap of the unintended light L11 with the emitted light L3 from the emission surface 2b is suppressed, and the visibility of the external scene at the emission surface 2b can be ensured.

[0040] The blind spot assisting device 1 of this embodiment is configured such that the optical member 2 that guides the incident light L2 is composed of a single member, and there is no displacement in the positions of the emission surface 2b that reflects and emits the incident light L2 to the outside and the smooth surface 2c that reflects the incident light L2, that is, the positions of the portions that function as a pair of mirrors. Further, the blind spot assisting device 1 does not require a fixing member for suppressing the displacement of the relative positions of the portions that function as a pair of mirrors in the optical member 2. Compared with the prior art, the number of parts is small, and high precision is not required for assembling to the holding member 3. Furthermore, a gap of a predetermined size or more is provided between the optical member 2 and the holding member 3, and total reflection on the smooth surface 2c can be ensured. In addition, since the blind spot assisting device 1 prevents unintended light from entering the smooth surface 2c from the outside by the light shielding member 4, the superposition of other unintended light on the emitted light L3 is suppressed, and the visibility of the external scene on the emission surface 2b can be ensured.

[0041] (Modification of the First Embodiment) The blind spot assisting device 1 may have a configuration in which the light shielding member 4 is disposed not only at the end portion on the incident surface 2a side but also at the end portion on the end surface 2d side of the smooth surface 2c, as shown in FIG. 9, for example. As a result, the blind spot assisting device 1 is configured such that the unintended light L 11 from the outside on the end surface 2d side does not enter the smooth surface 2c of the optical member 2 either.

[0042] According to this modification, in addition to the effects of the first embodiment, the unintended light L 11 from the outside on the end surface 2d side does not overlap with the emitted light L3, and the blind spot assisting device 1 can obtain the effect of further improving the visibility of the external scene on the emission surface 2b.

[0043] (Second Embodiment) The blind spot assisting device 1 of the second embodiment will be described. In FIG. 11, for the sake of clarity in showing the light guiding in the optical member 2 according to this embodiment, although a cross section is not shown, the outside scene light L1, the incident lights L2, L 21 、L 22 and the emitted light L3 are hatched.

[0044] As shown in, for example, FIG. 10, the blind spot assisting device 1 according to the present embodiment is different from the first embodiment in that the incident surface 2a of the optical member 2 protrudes more than the smooth surface 2c in the thickness direction of the optical member 2, and a part of the emission surface 2b is an emission region 2b1 composed only of the emission portion 21. In the present embodiment, this difference will be mainly described.

[0045] In the present embodiment, in the optical member 2, the incident surface 2a protrudes more than the smooth surface 2c in the thickness direction, and the surface of the portion of the incident surface 2a that protrudes from the smooth surface 2c is adjacent to the smooth surface 2c and is an inclined surface 2g that is inclined toward the smooth surface 2c. In other words, in the optical member 2, the incident surface 2a is, so to speak, a part of a large prism portion, and has a thickness that is partially larger than the thickness between the smooth surface 2c and the flat portion 22. The inclined surface 2g is formed with a light absorption film 211, for example, in the same manner as the second surface 21b of the emission portion 21, and is a surface on which the external scene light L1 does not enter.

[0046] In the present embodiment, since the area of the incident surface 2a of the optical member 2 is larger than that in the first embodiment, the area of the portion of the emission surface 2b where the incident light L2 from the incident surface 2a first reaches is larger. The optical member 2 can guide more light and is configured such that no light guiding gap is generated. The "light guiding gap" here means a gap in the light guiding direction between adjacent emission lights L3 sandwiching an emission portion 21 that does not emit light in a state where an emission portion 21 where the incident light L2 does not reach, that is, an emission portion 21 that does not emit the emission light L3 to the outside, is generated on the emission surface 2b. In other words, on the emission surface 2b, all of the plurality of emission portions 21 are in a state of emitting the emission light L3, and no gap is generated in the external scene visually recognized by the user.

[0047] In the present embodiment, a partial region from the end on the end surface 2d side of the emission surface 2b of the optical member 2 is an emission region 2b1 composed only of the plurality of emission portions 21. The emission region 2b1 is a region where the incident light L2 reflected by the smooth surface 2c is not reflected, and the emission of the emission light L3 to the outside from the first surface 21a is mainly performed.

[0048] Here, for example, as shown in FIG. 11, the width in the light guiding direction of the optical member 2 at the portion of the light emitting surface 2b where the incident light L2 from the incident surface 2a first arrives is L a is defined as such. Also, the width of the optical member 2 in the light guiding direction from the end on the light emitting surface 2b side of the incident surface 2a to the end on the end surface 2d side of the smooth surface 2c is L b is defined as such. At this time, the optical member 2 preferably has a configuration that satisfies the following equations (3) and (4).

[0049] L a =(2N - 1)×T0×tanφ ··· (3) L b =2N×T0×tanφ ··· (4) N in equations (3) and (4) is a positive integer. When the optical member 2 satisfies equations (3) and (4), the end of the incident light L2 that reaches the smooth surface 2c by repeated reflection at the light emitting surface 2b (L in FIG. 11 22 ) will coincide with the upper end of the end surface 2d. As a result, the end surface 2d is in a state where only the light rays reflected by the smooth surface 2c are incident, while the light rays reflected by the flat portion 22 of the light emitting surface 2b are not incident. That is, the emitted light from the end surface 2d is emitted only to the side of the light emitting surface 2b and not to the smooth surface 2c side. Therefore, the optical member 2 can emit light without waste in the user's viewing direction.

[0050] In addition to satisfying the above equations, by setting the portion of the light emitting surface 2b that exceeds L a as the emission region 2b1, all the incident light L2 that reaches the emission region 2b1 can be emitted in the user's viewing direction. That is, the number of the emission portions 21 of the portion that exceeds L a can be minimized, and thus the length of the optical member 2 in the light guiding direction can be reduced.

[0051] Note that L a may be within the range of the value represented by (2N - 1)×T0×tanφ ± 10%. Also, L bIt may also be within the range of the value represented by 2N×T0×tanφ ± 10%. This is because a deviation of about 10% may occur due to the angle of the incident light, and L a 、L b If L is within the above range, an effect of minimizing the loss of light guiding is expected.

[0052] In this embodiment, the light shielding member 4 is disposed, for example, at a portion located on the inclined surface 2g among the gaps between the optical member 2 and the accommodating portion 31 and at an end portion on the end surface 2d side. However, it may be disposed only at the portion located on the inclined surface 2g. Also in this embodiment, the light shielding member 4 disposed at the portion located on the inclined surface 2g can prevent unintended external scene light, that is, light L 11 from entering, and can suppress the superposition of unnecessary light L 11 on the emitted light L3. In this embodiment, among the gaps between the optical member 2 and the holding member 3, the "end portion on the incident surface 2a side" means a region on the incident surface 2a side of the smooth surface 2c. Further, since the portion of the light shielding member 4 that abuts on the inclined surface 2g does not contact the smooth surface 2c, its width is arbitrary. Furthermore, the portion of the light shielding member 4 that abuts on the inclined surface 2g only needs to be able to block the unintended light L 11 from reaching the smooth surface 2c, and the arrangement and height in the first direction D1 of the inclined surface 2g can be appropriately changed.

[0053] According to this embodiment, in addition to the effects of the first embodiment, the incident light L2 to the incident surface 2a of the optical member 2 can be guided to the emission surface 2b and the end surface 2d without waste, and the dead angle assisting device 1 can obtain an effect of minimizing the loss of light rays. Also, when the optical member 2 is configured to satisfy the above equations (3) and (4), while minimizing the loss of light rays, the area of the emission region 2b1 can be minimized, and an effect of reducing the length in the light guiding direction and thus the manufacturing cost can also be obtained.

[0054] (Third Embodiment) The dead angle assisting device 1 of the third embodiment will be described. In FIG. 14, similar to FIG. 11, it does not show a cross section, but hatching is applied to the external scene light L1, the incident light L2, and the emitted light L3.

[0055] In the blind spot assist device 1 of this embodiment, as shown in FIG. 12 for example, instead of the incident surface 2a, the optical member 2 has an incident portion 2h formed by a plurality of prism portions 23 on the plane formed by the smooth surface 2c, and has an incident side surface 2i connecting the incident portion 2h and the emission surface 2b. The blind spot assist device 1 is different from the first embodiment in this regard. In this embodiment, this difference will be mainly described.

[0056] In this embodiment, the optical member 2 has a configuration in which, as shown in FIGS. 12 and 13 for example, instead of the incident surface 2a, an incident portion 2h is arranged on the plane formed by the smooth surface 2c. The optical member 2 further has an incident side surface 2i connecting the incident portion 2h and the emission surface 2b, and the incident portion 2h is fixed to the holding member 3 in a state where it protrudes outward from the accommodating portion 31.

[0057] The incident portion 2h is formed by a plurality of prism portions 23 having similar shapes arranged continuously in alignment with each other. The plurality of prism portions 23 are, for example, triangular in cross-sectional view, and one surface of the outer surface opposite to the smooth surface 2c serves as an incident surface 23a for allowing a part of the external scene light L1 to enter inside. The plurality of prism portions 23 are arranged such that, for example, their respective incident surfaces 23a are substantially parallel. On the outer surface of the plurality of prism portions 23, the surface on the smooth surface 2c side serves as an adjacent surface 23b. For each of the plurality of prism portions 23, the inclination angle of the adjacent surface 23b is set to be equal to or less than a predetermined value so as not to obstruct the incidence of the external scene light L1 on the incident surface 23a of the other adjacent prism portions 23.

[0058] In the incident portion 2h, each of the valley portions that are the contact points between the incident surface 23a and the adjacent surface 23b of the adjacent prism portions 23 is located on the plane formed by the smooth surface 2c. That is, as shown in FIG. 14 for example, in the incident portion 2h, in each of the prism portions 23, the optical path length of the incident light L2 from the incident surface 23a to the flat portion 22 in the emission surface 2b is substantially the same. As a result, an effect is obtained in which the distortion of the external scene image visually recognized by the user due to the emission light L3 emitted from the emission portion 21 described later in the emission surface 2b is minimized.

[0059] The incident side surface 2i preferably has an inclination angle such that the incident angle φ of the incident light L2 to the flat portion 22 is φ or more, so that the incident light L2 is not emitted from the incident side surface 2i to the outside.

[0060] As shown in FIG. 14, for the optical member 2, the height in the normal direction of the flat portion 22 and the smooth surface 2c is T0, and the width in the light guiding direction of the incident portion 2h is W 2a Preferably, the design satisfies the following formula (5).

[0061] W 2a = 2T0 × tan φ ··· (5) W 2a When W = 2T0 × tan φ, as shown in FIG. 14 for the optical member 2, the area of the region on the emission surface 2b where the incident light L2 from the incident portion 2h first reaches becomes large, while the reflected light from the region reaches only the smooth surface 2c. As a result, there is no light guiding gap separating the plurality of emission portions 21 and the flat portion 22 between the emitted lights L3 from the emission surface 2b, and an effect of suppressing the light loss from the incident portion 2h is obtained. Note that the "light loss from the incident portion 2h" means the loss of light rays caused by the incident light L2 reflected by the flat portion 22 reaching the incident portion 2h again and being emitted from the incident portion 2h to the outside.

[0062] Since a deviation due to the angle of the incident light can occur by about 10%, if W I is within the range of the value represented by 2T0 × tan φ ± 10%, the optical member 2 has a configuration in which the above-described light loss and the influence of the light guiding gap are reduced.

[0063] In this embodiment, the light shielding member 4 is disposed, for example, at each of the end on the incident portion 2h side and the end on the end surface 2d side in the gap between the bottom surface 31a of the housing portion 31 and the smooth surface 2c, but it may be disposed only at the end on the incident portion 2h side.

[0064] According to the present embodiment, in addition to the effects of the first embodiment, the optical path lengths from the incident surfaces 23a to the emission surface 2b of the plurality of prism parts 23 constituting the incident part 2h are substantially the same, and the dead angle assisting device 1 can obtain the effect that the distortion of the external scene image visually recognized by the user at the emission surface 2b is minimized.

[0065] (Fourth Embodiment) The dead angle assisting device 1 of the fourth embodiment will be described with reference to FIG. 15. In FIG. 15, the outer contours of a part of the optical member 2 are shown by broken lines.

[0066] The dead angle assisting device 1 of the present embodiment is different from the first embodiment in that a light shielding film 5 is formed on a part of the upper surface 2e and the lower surface 2f of the optical member 2 that are not optical surfaces, as shown in FIG. 15 for example. In the present embodiment, this difference will be mainly described.

[0067] In the present embodiment, the optical member 2 has, for example, the end regions on the incident surface 2a side and the end surface 2d side of the upper surface 2e and the lower surface 2f covered by the light shielding film 5. The light shielding film 5 is, for example, a thin film of about 10 micrometers made of an arbitrary light-absorbing material such as black paint, and is formed by spray coating or the like. Thereby, the optical member 2 can suppress the incident of unintended external scene light from the upper surface 2e and the lower surface 2f and the unintended reflection on the upper surface 2e and the lower surface 2f inside, and the configuration is such that no noise occurs in the external scene that can be visually recognized from the emission surface 2b side. Note that the light shielding film 5 may be formed over the entire upper surface 2e and lower surface 2f. Further, the light shielding film 5 only needs to have a thickness and a material that do not hinder the attachment of the optical member 2 to the holding member 3 while blocking the unintended external scene light that is about to enter the upper surface 2e and the lower surface 2f of the optical member 2, and the thickness, material, etc. thereof can be appropriately changed.

[0068] According to the present embodiment, in addition to the effects of the first embodiment, the dead angle assisting device 1 can suppress the noise caused by the unintended incident of external scene light from the upper surface 2e and the lower surface 2f, and the visibility of the external scene at the emission surface 2b is further improved.

[0069] (Other Embodiments) Although the present disclosure has been described in accordance with the embodiments, it is understood that the present disclosure is not limited to the embodiments and structures. The present disclosure also includes various modifications and variations within the equivalent scope. In addition, various combinations and forms, and other combinations and forms including only one, more, or less of those elements, are within the scope and spirit of the present disclosure.

[0070] (1) As shown in, for example, FIG. 16, the optical member 2 may have a substantially trapezoidal cross-sectional view, excluding those located at the end on the incident surface 2a side among the plurality of injection portions 21. Among the plurality of injection portions 21, except for some injection portions 21, the first surface 21a and the second surface 21b are not adjacent to each other, and the tip surface thereof is a flat third surface 21c that connects the first surface 21a and the second surface 21b.

[0071] In the injection portion 21 having the third surface 21c, the light absorption film 211 is formed on the third surface 21c instead of the second surface 21b. Thereby, even if the incident light L2 is incident on the second surface 21b and unintended reflection occurs, the unintended reflected light is blocked by the light absorption film 211 formed on the third surface 21c and does not exit to the outside from the emission surface 2b. As a result, the unintended reflected light on the second surface 21b is superimposed on the emitted light L3 emitted to the outside from the first surface 21a, and an effect of suppressing the generation of noise can be obtained.

[0072] (2) As shown in, for example, FIG. 17, the emission surface 2b of the optical member 2 may be partitioned into a plurality of regions, and may have a different configuration for each region where the intervals between the injection portions 21 are partitioned. In this case, for example, the emission surface 2b is partitioned into three regions, a first region 2ba, a second region 2bb, and a third region 2bc, along the light guiding direction from the incident surface 2a side, and the interval between the injection portions 21 is smaller in the region closer to the end surface 2d side. Specifically, the ratio of the width W 23 of the injection portion 21 to the width W 21 of the flat portion 22 is larger in the second region 2bb than in the first region 2ba. And the third region 2bc is composed of only the injection portions 21.

[0073] More specifically, W 22 / W 21 The reflectance R inside the emission surface 2b represented by W is, for example, 2 / 3 in the first region 2ba, 1 / 2 in the second region 2bb, and 0 in the third region 2bc. In this case, taking the incident light L2 from the incident surface 2a as 100%, the first region 2ba reflects approximately 67% corresponding to 2 / 3 of the incident light L2 to the smooth surface 2c, and the remaining approximately 33% is emitted from the emission part 21 to the outside. The second region 2bb reflects approximately 34% corresponding to 1 / 2 of the approximately 67% of the incident light L2 which is the reflected light in the first region 2ba to the smooth surface 2c, and the remaining approximately 33% is emitted from the emission part 21 to the outside. The third region 2bc emits the approximately 33% of the incident light L2 which is the reflected light in the second region 2bb from the emission part 21 to the outside. Thereby, the optical member 2 is averaged so that the light amounts of the emitted light L3 in each region from the first region 2ba to the third region 2bc are about the same, and has a structure in which brightness unevenness due to the viewpoint position of the user is reduced.

[0074] Also, in this case, as shown in FIG. 18 for example, the optical member 2 may have the other emission parts 21 in a substantially trapezoidal shape in cross-sectional view, excluding the emission part 21 located on the incident surface 2a side in the first region 2ba and the emission part 21 located on the most end surface 2d side in the third region 2bc. In this case, in addition to the effect of reducing the above-mentioned brightness unevenness, in the first region ca and the second region 2bb, the optical member 2 can also obtain the effect of suppressing noise caused by the unintentional reflection of the incident light L2 on the second surface 21b of the emission part 21.

[0075] (3) The optical member 2 may have a configuration in which, as shown in FIG. 19 for example, the arrangement direction of the plurality of prism parts 23 constituting the incident part 2h is taken as the prism arrangement direction, and the prism arrangement direction is the direction connecting the emission surface 2b and the smooth surface 2c. Even in this case, the optical member 2 has a structure in which no relative positional deviation occurs between the two paired reflecting surfaces, that is, the flat part 22 and the smooth surface 2c, and no accuracy is required when attaching to the holding member 3.

[0076] (4) Except in cases where it is clearly impossible to achieve both, the optical member 2 may be configured to include some or all of the components in the above-described other embodiments (1) to (3), or to adopt the configurations employed in the above-described first to fourth embodiments and their modifications, or to freely combine them. For example, in the blind spot assist device 1 of the above-described first to fourth embodiments, the optical member 2 may have a part of the injection part 21 with a substantially trapezoidal shape, or may divide the light emitting surface 2b into a plurality of regions and change the intervals between the injection parts 21 for each divided region. Further, for example, in the above-described first to third embodiments and their modifications, the optical member 2 may be configured such that a light shielding film 5 is formed on part or all of the upper surface 2e and the lower surface 2f. Further, for example, in the second embodiment, the optical member 2 may be configured such that the light emitting surface 2b does not have the emission region 2b1. As described above, the blind spot assist device 1 may be configured to freely combine the components of the above-described embodiments and modifications within the possible range.

[0077] (5) It goes without saying that in the above-described embodiments, the elements constituting the embodiments are not necessarily essential, except in cases where it is explicitly stated that they are particularly essential or in cases where they are considered to be clearly essential in principle. Further, in the above-described embodiments, when numerical values such as the number, numerical value, quantity, range, etc. of the components of the embodiments are mentioned, they are not limited to that specific number, except in cases where it is explicitly stated that they are particularly essential or in cases where they are clearly limited to a specific number in principle. Further, in the above-described embodiments, when referring to the shape, positional relationship, etc. of the components, etc., they are not limited to that shape, positional relationship, etc., except in cases where it is explicitly stated or in cases where they are clearly limited to a specific shape, positional relationship, etc. in principle.

[0078] (Features of the present invention) [Claim 1] A blind spot assist device, an incident surface (2a, 23a) on which external light is incident, a light emitting surface (2b) having a plurality of injection parts (21) and a plurality of flat parts (22), and being the first surface that the incident light incident from the incident surface reaches, and a smooth surface (2c) disposed opposite to the plurality of flat parts, and an optical member (2) made of a translucent material; It has a housing portion (31) for housing the optical member, and a holding member (3) for holding the optical member, Taking the surface of the housing portion facing the smooth surface of the optical member as the bottom surface (31a), among the gaps between the surface of the optical member including the smooth surface and the bottom surface of the housing portion, a light-shielding member (4) disposed at least at the end on the incident surface side, The plurality of flat portions are the first reflecting surfaces that reflect the incident light toward the smooth surface by total reflection, The smooth surface is the second reflecting surface that reflects the reflected light reflected by the flat portion toward the emission surface by total reflection, The plurality of emission portions are a dead angle assisting device that emits a part of the incident light or a part of the light reflected by the smooth surface to the outside on the side opposite to the holding member. [Claim 2] The light-shielding member is also disposed at the end of the gap opposite to the incident surface, The dead angle assisting device according to claim 1. [Claim 3] The light-shielding member is made of an elastic body, The dead angle assisting device according to claim 1 or 2. [Claim 4] The light-shielding member is made of a light absorber, The dead angle assisting device according to any one of claims 1 to 3. [Claim 5] The light-shielding member is a member integrated with the optical member or the holding member, The dead angle assisting device according to any one of claims 1 to 4. [Claim 6] Among the optical members, the surface connecting the smooth surface and the emission surface, with two opposed surfaces as the upper surface (2e) and the lower surface (2f), at least a part of the upper surface or the lower surface of the optical member is covered with a light-shielding film (5), The dead angle assisting device according to any one of claims 1 to 5.

Explanation of Signs

[0079] 2 ··· Optical member, 21 ··· Emission portion 21 ··· Flat portion, 2a, 23a ··· Incident surface, 2b ··· emission surface 2b ··· smooth surface, 2e ··· upper surface 2e ··· lower surface, 3 ··· holding member, 31 ··· accommodating portion, 31a ··· bottom surface, 4 ··· light-shielding member, 5 ··· light-shielding film

Claims

Claim 1 A blind spot assisting device, comprising: an incident surface (2a, 23a) on which external light is incident, having a plurality of emission portions (21) and a plurality of flat portions (22), an emission surface (2b) on which the incident light incident from the incident surface first arrives, and a smooth surface (2c) disposed opposite to the plurality of flat portions, an optical member (2) made of a light-transmissive material; a housing portion (31) for housing the optical member, and a holding member (3) for holding the optical member; a light-shielding member (4) disposed at least at an end portion on the incident surface side among gaps between the smooth surface of the optical member and the bottom surface (31a) of the housing portion with respect to the surface of the housing portion facing the smooth surface of the optical member; the plurality of flat portions are first reflecting surfaces that reflect the incident light toward the smooth surface by total reflection; the smooth surface is a second reflecting surface that reflects the reflected light reflected by the flat portion toward the emission surface by total reflection; the plurality of emission portions emit a part of the incident light or a part of the light reflected by the smooth surface to the outside on the side opposite to the holding member, the blind spot assisting device. Claim 2 The blind spot assisting device according to claim 1, wherein the light-shielding member is also disposed at an end portion on the side opposite to the incident surface among the gaps. Claim 3 The blind spot assisting device according to claim 2, wherein the light-shielding member is made of an elastic body. Claim 4 The blind spot assisting device according to claim 3, wherein the light-shielding member is made of a light absorber. Claim 5 The blind spot assisting device according to claim 4, wherein the light-shielding member is a member integrated with the optical member or the holding member. Claim 6 Among the surfaces of the optical member connecting the smooth surface and the emission surface, with two opposed surfaces being an upper surface (2e) and a lower surface (2f), the optical member has at least a part of the upper surface or the lower surface covered with a light-shielding film (5), the blind spot assisting device according to any one of claims 1 to 5.

Images