Vehicle lamp

Abstract

To prevent light emitted from a light source and incident on a plate-like light guide body from being emitted in an unintended direction, in a vehicular lighting fixture equipped with the plate-like light guide body.SOLUTION: Light from a light source incident on a first end face of a plate-shaped light guide 40 is guided toward a second end face, and a plurality of reflecting elements 40s for totally reflecting the light from the light source toward the front of a lamp are formed as trapezoidal recessed parts on a rear face 40b of the plate-shaped light guide 40. At this time, the inclination angle θ 2 of the inclined flat surface 40s2 located on the second end surface side in the trapezoidal recess is set to a value larger than the inclination angle θ 1 of the inclined convex curved surface 40s1 located on the first end surface side. Thus, the return light from the second end surface totally reflected by the connection part 40b between the rear surface 40s2 and the inclined plane 40s2a is totally reflected again by the inclined plane 40s2, so that the emission light from the front surface 40a of the plate-shaped light guide body 40 does not become light traveling in a direction largely inclined toward the first end surface.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a vehicle lamp having a plate-shaped light guide. [Background technology]

[0002] 2. Description of the Related Art Conventionally, a vehicle lamp has been described that includes a light guide that is arranged so as to extend in a required direction that intersects with the longitudinal direction of the lamp.

[0003] Patent Document 1 describes such a vehicle lamp that guides light emitted from a light source that is incident on a light guide from a first end face in the required direction and causes the light to be emitted from the light guide forward by total reflection by a plurality of reflecting elements formed on the back surface of the light guide. In the light guide described in Patent Document 1, each of the plurality of reflecting elements is formed as a ridge portion having a wedge-shaped cross section.

[0004] Furthermore, Patent Document 2 discloses a light guide in such a vehicle lamp that includes a plate-shaped light guide. In the plate-shaped light guide disclosed in Patent Document 2, each of a plurality of reflective elements is formed as a concave groove having a wedge-shaped cross section. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-156340 [Patent Document 2] Japanese Patent Application Publication No. 2018-92753 Summary of the Invention [Problem to be solved by the invention]

[0006] In a vehicle lamp having a plate-shaped light guide, if each of the multiple reflective elements is formed as a trapezoidal recess having a trapezoidal cross-sectional shape, the light emitted from the light source and incident on the plate-shaped light guide can be totally reflected not only by the front and rear surfaces of the plate-shaped light guide but also by the bottom surface of the trapezoidal recess, thereby making it possible to increase the light-guiding efficiency of the plate-shaped light guide.

[0007] Furthermore, in a plate-shaped light guide, a portion of the light emitted from the light source and incident on its first end face may be totally reflected by a second end face located opposite the first end face, resulting in returned light traveling toward the first end face. Furthermore, depending on the configuration of the lighting fixture, a portion of the light emitted from the light source and incident on the first end face of the plate-shaped light guide may be reflected by a surface of a peripheral component after emitting from the second end face, and then re-enter from the second end face, resulting in returned light traveling toward the first end face. Emitting such returned light from the plate-shaped light guide toward the front of the lighting fixture would enable the plate-shaped light guide to emit light more brightly, but adopting such a configuration may result in the following problems.

[0008] That is, when such returned light reaches the surface located on the second end face side of the trapezoidal recess, some of the light that is totally reflected by this surface may exit the front surface of the plate-shaped light guide as light traveling in a direction significantly inclined toward the first end face. Specifically, in the plate-shaped light guide, a corner R is inevitably formed at the connection between the rear surface and the surface located on the second end face side of the trapezoidal recess, and light that is totally reflected at this connection may exit the front surface of the plate-shaped light guide as light traveling in a direction significantly inclined toward the first end face. If light exits the plate-shaped light guide in this way in an unintended direction, this may cause inconvenience in terms of traffic safety or the visibility of the lamp, depending on the type of lamp.

[0009] The present invention has been made in consideration of the above circumstances, and aims to provide a vehicle lamp equipped with a plate-shaped light guide that can prevent light emitted from a light source that has entered the plate-shaped light guide from being emitted in an unintended direction. [Means for solving the problem]

[0010] The present invention aims to achieve the above object by devising a light guide structure.

[0011] That is, the vehicle lamp according to the present invention is A vehicle lamp including a light source and a plate-shaped light guide, The plate-shaped light guide is disposed so as to extend in a required direction intersecting with the front-rear direction of the lamp, the light source includes a first light-emitting element arranged to cause light to be incident on the plate-shaped light guide from a first end face of the plate-shaped light guide in the required direction, A plurality of reflecting elements are formed on the rear surface of the plate-shaped light guide, and the reflecting elements totally reflect the light from the first light-emitting element that is incident on the plate-shaped light guide toward the front of the lamp, Each of the plurality of reflecting elements is formed as a trapezoidal recess having a trapezoidal cross-sectional shape, and the inclination angle of the surface located opposite the first end face is set to a value greater than the inclination angle of the surface located on the first end face side.

[0012] The "required direction" is not particularly limited as long as it is a direction that intersects with the front-rear direction of the lamp.

[0013] The "plate-shaped light guide" is not particularly limited in its specific outer shape or surface shape, as long as it is disposed so as to extend in the required direction.

[0014] The "first light emitting element" is not particularly limited in its specific arrangement or shape of its light emitting surface, as long as it is arranged so that light is incident on the plate-like light guide from its first end face.

[0015] The specific arrangement and number of the "plurality of reflecting elements" are not particularly limited.

[0016] Each of the above "multiple reflective elements" is formed as a trapezoidal recess, and the inclination angle of the surface located opposite the first end face is set to a value greater than the inclination angle of the surface located on the first end face side, so long as this is set. [Effects of the Invention]

[0017] The vehicle lamp of the present invention is configured so that light is incident on a plate-shaped light guide extending in a required direction that intersects the fore-and-aft direction of the lamp from a first end face in the required direction. The rear face of the plate-shaped light guide is formed with a plurality of reflective elements that totally reflect light from the first light-emitting element that has entered the plate-shaped light guide towards the front of the lamp, and each of these is formed as a trapezoidal recess.As a result, the light emitted from the first light-emitting element that has entered the plate-shaped light guide can be totally reflected not only by the front and rear faces of the plate-shaped light guide but also by the bottom faces of the trapezoidal recesses, thereby improving the light guide efficiency.

[0018] Furthermore, a portion of the emitted light from the first light-emitting element that enters the plate-shaped light guide from the first end face is totally reflected by the second end face located opposite the first end face, becoming return light toward the first end face, or, depending on the configuration of the lighting fixture, after emitting from the second end face, it is reflected by the surface of a surrounding component and re-enters the plate-shaped light guide from the second end face, becoming return light toward the first end face.However, by emitting such return light from the plate-shaped light guide toward the front of the lighting fixture, the plate-shaped light guide can be made to emit light more brightly.

[0019] Furthermore, since the inclination angle of the surface of each of the multiple reflecting elements located opposite the first end face is set to a value greater than the inclination angle of the surface located on the first end face side, the following effects can be obtained.

[0020] In other words, in the plate-shaped light guide, a corner R is inevitably formed at the connection between the rear surface and the surface located on the second end face side of the trapezoidal recess, but the light that is totally reflected at this connection part can be totally reflected again on the surface located on the second end face side, thereby preventing the light emitted from the front surface of the plate-shaped light guide from traveling in a direction that is significantly inclined toward the first end face.

[0021] Thus, according to the present invention, in a vehicle lamp equipped with a plate-shaped light guide, it is possible to prevent light emitted from a light source that enters the plate-shaped light guide from being emitted in an unintended direction.

[0022] As a result, the following specific effects can be obtained.

[0023] That is, for example, if the vehicle lighting fixture is a rear turn signal lamp (RTSL) mounted on the rear side of the vehicle and the first end face in the required direction is located on the front side of the vehicle, if part of the emitted light from the plate-shaped light guide is emitted in a direction close to the front of the vehicle, the red light will cause discomfort to drivers of nearby vehicles, etc.

[0024] In contrast, in the vehicle lighting fixture of the present invention, even if the first end face in the required direction is located on the front side of the vehicle, it is possible to prevent a portion of the light emitted from the plate-shaped light guide from being emitted as red light in a direction close to the front of the vehicle, thereby preventing drivers of nearby vehicles from feeling uncomfortable.

[0025] In the above configuration, if each of the plurality of reflective elements is formed as a frustum-shaped recess, and these plurality of reflective elements are arranged alternately in the required direction and a direction perpendicular to the required direction in a plurality of grid-like regions divided in the required direction and a direction perpendicular to the required direction, it becomes possible to easily emit the light emitted from the first light-emitting element that is incident on the plate-shaped light guide toward the front of the lamp with approximately uniform brightness in two dimensions from the plate-shaped light guide.

[0026] In this case, the specific surface shape of the "frustum-shaped recess" is not particularly limited, and for example, a surface shape based on a truncated pyramid having a surface shape such as a square pyramid or a hexagonal pyramid, or a surface shape such as a cone or an elliptical cone tilted in the required direction can be used.

[0027] In the above configuration, if each of the plurality of reflecting elements has a surface located on the first end face side of the plate-like light guide formed into a convex curved shape, the light emitted from the first light-emitting element and incident on the plate-like light guide can be totally reflected as light that diffuses in a direction perpendicular to the required direction, thereby making the plate-like light guide appear to glow with more uniform brightness. In this case, the specific shape of the "convex curved shape" can be a part of a conical surface or an elliptical conical surface, or a part of a spherical surface or an elliptical spherical surface, etc.

[0028] In the above configuration, if the configuration of the multiple reflective elements is such that the reflective elements located farther from the first end face of the plate-shaped light guide are formed as deeper trapezoidal recesses, the amount of light totally reflected by each of the multiple reflective elements can be maintained at a substantially constant value regardless of the distance from the first end face, thereby making the plate-shaped light guide appear to glow with a more uniform brightness.

[0029] In the above configuration, if the light source further includes a second light-emitting element arranged to cause light to enter the plate-shaped light guide from its rear side, and if a lens portion is formed in a portion of the plate-shaped light guide closer to the first end face than the multiple reflecting elements, the lens portion controls the emission of light from the second light-emitting element that has entered the plate-shaped light guide toward the front of the lamp, the following effects can be obtained.

[0030] That is, in the region of the plate-shaped light guide closer to the first end face, a portion of the light emitted from the first light-emitting element and incident from the first end face is not sufficiently totally reflected by the multiple reflecting elements, which tends to result in a relatively insufficient brightness. In contrast, by forming a lens portion that controls the emission of light from the second light-emitting element that has entered the plate-shaped light guide toward the front of the lamp in a portion of the plate-shaped light guide that is located closer to the first end face than the multiple reflecting elements, it is possible to ensure sufficient brightness in the region of the plate-shaped light guide closer to the first end face.

[0031] Instead of the above configuration, it is also possible to configure the plurality of reflecting elements so that each is formed as a trapezoidal convex portion, and the inclination angle of the surface located on the first end face side is set to a value larger than the inclination angle of the surface located on the opposite side from the first end face. Even when such a configuration is adopted, the same effects as those of the above configuration can be obtained. In this case, it is also possible to adopt a configuration in which the trapezoidal convex portion is formed as a frustum-shaped convex portion. [Brief explanation of the drawings]

[0032] [Figure 1] FIG. 1 is a front view showing a vehicle lamp according to an embodiment of the present invention; [Figure 2] Cross section of line II-II in Figure 1 [Figure 3] FIG. 2 is a plan view showing the vehicle lamp mounted on a vehicle. [Figure 4] Detailed view of part IV in Figure 2 [Figure 5] View from the V direction of Figure 4 [Figure 6] Detailed view of part VI in Figure 4 [Figure 7] FIG. 5 is a view similar to FIG. 4, showing a first modified example of the embodiment; [Figure 8] FIG. 5 is a view substantially similar to FIG. 4, showing a second modification of the embodiment; [Figure 9] FIG. 5 is a view similar to FIG. 4, showing a third modification of the embodiment; DETAILED DESCRIPTION OF THE INVENTION

[0033] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0034] Fig. 1 is a front view showing a vehicle lamp 10R according to one embodiment of the present invention, Fig. 2 is a cross-sectional view taken along line II-II in Fig. 1. Fig. 3 is a plan view showing the vehicle lamp 10R mounted on a vehicle 100.

[0035] 1 to 3, the direction indicated by X is the "forward" direction of the vehicle lamp 10R (the "rightward" direction of the vehicle), the direction indicated by Y is the "leftward" direction (the "forward" direction of the vehicle), and the direction indicated by Z is the "upward" direction. This is the same in other figures.

[0036] As shown in FIG. 3, the vehicle lamp 10R according to this embodiment is a rear turn signal lamp (RTSL) mounted on the rear right side of the vehicle 100, and is configured to illuminate intermittently together with other turn signal lamps (not shown) when the vehicle 100 is turning right, thereby emitting red light toward the right side area of ​​the vehicle 100.

[0037] The light distribution performance of the vehicular lamp 10R is preferably such that it appears to shine as brightly as possible in a central region within an angle α on both the front and rear sides of the vehicle, centered on a straight line L extending directly across from the rear right side of the vehicle 100, while in a region extending forward from the straight line L beyond an angle β (β>α) (i.e., the region closer to the front of the vehicle, indicated by the dotted line in the figure), it is preferable that it appears as dark as possible to prevent drivers of nearby vehicles from feeling uncomfortable when the vehicular lamp 10R is lit in red. Specifically, in a region where α≦30°, it is preferable that it appears to shine with a brightness of 0.6 cd or more, while in a region where angle β>60°, it is preferable that it be limited to a brightness of 0.25 cd or less.

[0038] As shown in FIG. 3, a vehicle lamp 10L having a configuration symmetrical to the vehicle lamp 10R is mounted on the rear left side of the vehicle 100.

[0039] Next, a specific configuration of the vehicle lamp 10R will be described.

[0040] As shown in Figures 1 and 2, the vehicle lamp 10R is configured such that first and second light-emitting elements 20, 30 as light sources and a plate-shaped light guide 40 are housed together with an extension panel 50 within a lamp chamber formed by a lamp body 12 and a plain, translucent cover 14 attached to the lamp body 12.

[0041] The vehicular lamp 10R has an outer shape that is substantially horizontally elongated and trapezoidal when viewed from the front of the lamp (i.e., when viewed from the right side of the vehicle). Specifically, the vehicular lamp 10R is formed so that its vertical width gradually increases from its left end (i.e., the front side of the vehicle and the right end side when viewed from the front of the lamp) to its right end. In this regard, the vehicular lamp 10R is formed so that its upper edge extends horizontally, and its left end and right end are formed with a constant vertical width.

[0042] The first light-emitting element 20 is a red light-emitting diode, and is mounted on the substrate 22 at the left end of the lamp chamber (i.e., the end on the front side of the vehicle) with its light-emitting surface facing right (i.e., rear of the vehicle). The second light-emitting element 30 is also a red light-emitting diode, and is mounted on the substrate 32 near the left end of the lamp chamber with its light-emitting surface facing forward of the lamp (i.e., to the right side of the vehicle).

[0043] The plate-shaped light guide 40 is an injection-molded product made of transparent resin, and is formed in a generally flat plate shape, with a horizontally elongated, generally trapezoidal outer shape that is slightly smaller than the outer shape of the vehicle lamp 10. That is, the plate-shaped light guide 40 is disposed along a vertical plane extending in the left-right direction (i.e., the vehicle front-rear direction), and the vertical width of a second end face 40d that constitutes its right end face is set to be larger than the vertical width of a first end face 40c that constitutes its left end face.

[0044] The front surface 40a of the plate-shaped light guide 40 is formed in a flat shape, while the rear surface 40b is configured such that a plurality of reflecting elements 40s are formed on the flat surface as trapezoidal recesses each having a trapezoidal cross section.

[0045] Specifically, each of the plurality of reflective elements 40s is formed as a truncated cone-shaped recess. The plurality of reflective elements 40s are alternately arranged in the vertical and horizontal directions in a plurality of lattice-shaped regions A that are divided vertically and horizontally. The plurality of lattice-shaped regions A are located within a range of a horizontally elongated, approximately trapezoidal shape that is slightly smaller than the outer shape of the plate-like light guide 40.

[0046] The plate-shaped light guide 40 is configured so that light emitted from the first light-emitting element 20 and incident on its first end face 40c is totally reflected by the plurality of reflecting elements 40s toward the front of the lamp. Furthermore, a lens section 42 is formed in the left end region of the plate-shaped light guide 40 (i.e., the region located to the left of the plurality of grid-shaped regions A) to control the emission of light from the second light-emitting element 30 and incident on its rear face 40b toward the front of the lamp. The lens section 42 is configured as a plano-convex lens that protrudes in a convex curved shape from the rear face 40b of the plate-shaped light guide 40.

[0047] The plate-shaped light guide 40 is supported by the lamp body 12 via a support structure (not shown).

[0048] The extension panel 50 is disposed on the front side of the lamp of the plate-shaped light guide 40 so as to surround the outer peripheral edge thereof. That is, the extension panel 50 has a horizontally elongated, generally trapezoidal opening 50a that surrounds the plurality of grid-shaped regions A and the lens portions 42 of the plate-shaped light guide 40. A flange portion 50b that extends toward the rear of the lamp and surrounds the plate-shaped light guide 40 is formed on the outer peripheral edge of the extension panel 50, and the extension panel is supported by the lamp body 12 at this flange portion 50b. Furthermore, the inner surface of the right region of the flange portion 50b (i.e., the inner surface facing the front of the vehicle) is mirror-finished by aluminum vapor deposition or the like, thereby forming a reflective surface 52.

[0049] The substrate 22 is supported by the flange portion 50b of the extension panel 50 in a state in which the light-emitting surface of the first light-emitting element 20 is positioned directly opposite the center position of the first end face 40c of the plate-like light guide 40. The substrate 32 is supported by the lamp body 12 in a state in which the light-emitting surface of the second light-emitting element 30 is positioned directly opposite the lens portion 42 of the plate-like light guide 40.

[0050] The light-transmitting cover 14 is formed so as to extend along the shape of the vehicle body at the rear right side of the vehicle 100, and the extension panel 50 is also formed so as to extend along this light-transmitting cover 14.

[0051] Next, the optical function of the plate-shaped light guide 40 will be outlined.

[0052] 2, light emitted from the first light-emitting element 20 and incident on the first end face 40c of the plate-shaped light guide 40 is guided to the right while being totally reflected by the front face 40a and rear face 40b. A portion of the light totally reflected by the multiple reflecting elements 40s during this light-guiding process is emitted toward the front of the lamp. On the other hand, of the light that reaches the second end face 40d of the plate-shaped light guide 40, a portion of the light is totally reflected by the second end face 40d, and the rest is emitted from the second end face 40d, reflected by the reflecting surface 52 of the extension panel 50, and then re-enters the plate-shaped light guide 40 from the second end face 40d. The returned light totally reflected by the second end face 40d and the returned light re-entering from the second end face 40d are guided toward the first end face 40c, totally reflected by the multiple reflecting elements 40s during this light-guiding process, and emitted toward the front of the lamp.

[0053] Furthermore, the light emitted from the second light emitting element 30 and incident on the lens portion 42 of the plate-shaped light guide 40 is emitted as diffused light from the front surface 40a of the plate-shaped light guide 40 toward the front of the lamp.

[0054] Next, how the light emitted from the first light emitting element 20 is guided by the plate-shaped light guide 40 will be described in detail.

[0055] Fig. 4 is a detailed view of part IV in Fig. 2. Fig. 4(a) shows how light emitted from the first light-emitting element 20 and incident from the first end face 40c of the plate-like light guide 40 is totally reflected by one reflecting element 40s, and Fig. 4(b) shows how light returning from the second end face 40d of the plate-like light guide 40 is totally reflected by the reflecting element 40s.

[0056] 5 is a view seen in the direction of the arrow V in FIG. 4, and is a perspective view showing the rear surface 40b and the plurality of reflecting elements 40s from inside the plate-shaped light guide 40. FIG.

[0057] 4 and 5, the plurality of reflective elements 40s are all formed as truncated pyramidal recesses having the same shape. Each of the plurality of reflective elements 40s has an outer shape that is a partially deformed truncated pyramidal shape.

[0058] Specifically, each of the plurality of reflective elements 40s has inclined flat surfaces 40s2, 40s3, 40s4 on the surface facing the second end face 40d of the plate-shaped light guide 40 (i.e., the right side) and on both the top and bottom sides, and has an inclined convex curved surface 40s1 made up of a part of a conical surface on the surface facing the first end face 40c of the plate-shaped light guide 40 (i.e., the left side). As a result, the bottom surface 40s0 of the frustum-shaped recess constituting each of the plurality of reflective elements 40s has an outer shape in which the right side of the rectangular shape bulges out in a convex arc shape when the lamp is viewed from the front.

[0059] 4, in each of the plurality of reflecting elements 40s, the inclination angle θ2 of the inclined flat surface 40s2 located on the second end face 40d side (i.e., on the right side) is set to a value greater than the inclination angle θ1 of the inclined convex curved surface 40s1 located on the first end face 40c side (i.e., on the left side) of the plate-shaped light guide 40. Specifically, for example, the inclination angle θ1 is set to a value of approximately θ1=55°, and the inclination angle θ2 is set to a value of approximately θ2=65°. Note that in each of the plurality of reflecting elements 40s, the inclination angles of the inclined flat surfaces 40s2 and 40s3 located above and below the bottom face 40s0 are set to a value intermediate between the inclination angles θ1 and θ2.

[0060] 5, in each of the plurality of reflecting elements 40s, the connection portions between the inclined convex curved surface 40s1 and the inclined flat surfaces 40s2, 40s3, 40s4 and the bottom surface 40s0 are formed by pin angles, but the connection portions 40s1a, 40s2a, 40s3a, 40s4a between the inclined convex curved surface 40s1 and the inclined flat surfaces 40s2, 40s3, 40s4 and the rear surface 40b of the plate-like light guide 40 are formed by convex cylindrical surfaces. This is because, when processing the portions corresponding to the frustum-shaped recesses that constitute each of the plurality of reflecting elements 40s in a mold for forming the plate-like light guide 40, corners R are inevitably formed at the connection portions between the inclined convex curved surface 40s1 and the inclined flat surfaces 40s2, 40s3, 40s4 and the rear surface 40b of the plate-like light guide 40.

[0061] As shown in Fig. 4(a), after entering the plate-shaped light guide 40, light is totally reflected by the front surface 40a, and then totally reflected by the rear surface 40b and the bottom surface 40s0 of the reflecting element 40s. At this time, the light that reaches the inclined convex curved surface 40s1 after being totally reflected by the rear surface 40b is totally reflected by this inclined convex curved surface 40s1 and reaches the front surface 40a. However, since the incident angle is sufficiently smaller than the critical angle of the plate-shaped light guide 40, the light is not totally reflected by the front surface 40a and is emitted forward of the lamp. The emission angle at this time is relatively small (smaller than the angle α shown in Fig. 3).

[0062] On the other hand, light that has been totally reflected by the front surface 40a and then directly reaches the inclined convex curved surface 40s1 is emitted directly from this inclined convex curved surface 40s1 to the rear of the lamp.

[0063] Furthermore, after being totally reflected by the front surface 40a, the light that reaches the connecting portion 40s1a of the inclined convex curved surface 40s1 is totally reflected by this connecting portion 40s1a and then reaches the front surface 40a at a relatively large incident angle that is smaller than the critical angle of the plate-shaped light guide 40. Therefore, this light is not totally reflected by the front surface 40a and is emitted in a direction shifted to the right toward the front of the lamp. The emission angle at this time is quite large, and in some cases may be larger than the angle obtained by inverting the angle β shown in FIG. 3.

[0064] As shown in FIG. 4(b), the returning light incident on the plate-shaped light guide 40 is also guided along a light path that is essentially the left-right inversion of the light path shown in FIG. 4(a). However, after being totally reflected by the front surface 40a, the light that reaches the connecting portion 40s2a of the inclined flat surface 40s2 does not reach the front surface 40a directly after being totally reflected by the connecting portion 40s2a, but rather reaches the front surface 40a after being totally reflected by the inclined flat surface 40s2. This is because the inclination angle θ2 of the inclined flat surface 40s2 is set to a large value. The light that reaches the front surface 40a is then emitted slightly to the right toward the front of the lamp.

[0065] Next, a detailed description will be given of how the return light incident on the plate-shaped light guide 40 is totally reflected by the inclined plane 40s2 of the reflecting element 40s.

[0066] FIG. 6 is a detailed view of the VI portion of FIG.

[0067] 6, the optical path indicated by the two-dot chain line is the optical path when the inclined flat surface 40s2 of the plate-shaped light guide 40 is formed as an inclined flat surface 40s2'. The inclination angle θ2' of this inclined flat surface 40s2' is set to the same value as the inclination angle θ1 of the inclined convex curved surface 40s1 (i.e., a value smaller than the inclination angle θ2).

[0068] As shown by the two-dot chain line in Figure 6, the light that reaches the inclined plane 40s2' after being totally reflected by the rear surface 40b of the plate-shaped light guide 40 becomes light that, after being totally reflected by this inclined plane 40s2', travels in a direction more to the left than the light that was totally reflected by the inclined plane 40s2.

[0069] On the other hand, light that reaches the inclined plane 40s2' without being totally reflected at the rear surface 40b of the plate-shaped light guide 40 is emitted from this inclined plane 40s2' to the rear of the lamp, but light that reaches the connection portion 40s2a' of the inclined plane 40s2' without being totally reflected at the rear surface 40b of the plate-shaped light guide 40 is totally reflected at this connection portion 40s2a' and then, depending on the angle of incidence, becomes light that heads in a direction significantly inclined to the left without reaching the inclined plane 40s2'.

[0070] In contrast, as shown by the solid line in Figure 6, light that reaches the connection portion 40s2a of the inclined plane 40s2 without being totally reflected at the rear surface 40b of the plate-shaped light guide 40 is totally reflected at this connection portion 40s2a, then reaches the inclined plane 40s2, and after being totally reflected at this inclined plane 40s2, becomes light that travels in a direction slightly inclined to the left.

[0071] As shown in Figure 5, light that reaches the inclined convex curved surface 40s1 after being totally reflected by the rear surface 40b of the plate-shaped light guide 40 is then totally reflected by this inclined convex curved surface 40s1 and becomes light that travels toward the front surface 40a at an angle smaller than the critical angle of the plate-shaped light guide 40.

[0072] In this case, since the inclined convex surface 40s1 is formed in a convex shape, if the light reaching the inclined convex surface 40s1 is assumed to be parallel light, the light totally reflected by the inclined convex surface 40s1 becomes light that is diffused in the vertical direction, and if the light reaching the inclined convex surface 40s1 is assumed to be convergent in the vertical direction, the light totally reflected by the inclined convex surface 40s1 becomes approximately parallel light. Therefore, the light emitted from the plate-like light guide 40 has a certain degree of spread in the vertical direction as well.

[0073] Next, the effects of this embodiment will be described.

[0074] The vehicle lamp 10 of this embodiment is configured so that light is incident on a plate-shaped light guide 40, which extends in the left-right direction (a required direction intersecting the front-to-rear direction of the lamp) when viewed from the front of the lamp, from its first end face 40c, which is its left end face.The rear face 40b of the plate-shaped light guide 40 is formed with a plurality of reflective elements 40s that totally reflect light from the first light-emitting element 20 that has entered the plate-shaped light guide 40 towards the front of the lamp, and each of these is formed as a trapezoidal recess.As a result, the light emitted from the first light-emitting element 20 that has entered the plate-shaped light guide 40 can be totally reflected not only by the front face 40a and rear face 40b of the plate-shaped light guide 40, but also by the bottom face 40s0 of the trapezoidal recess, thereby improving the light guiding efficiency.

[0075] Furthermore, a portion of the light emitted from the first light-emitting element 20 and incident on the plate-shaped light guide 40 from the first end face 40c is totally reflected by the second end face 40d located on the opposite side to the first end face 40c, becoming return light toward the first end face 40c, or after emitting from the second end face 40d, is reflected by the reflective surface 52 (surface of the peripheral component) of the extension panel 50, and re-enters the plate-shaped light guide 40 from the second end face 40d, becoming return light toward the first end face 40c. However, by emitting such return light from the plate-shaped light guide 40 forward of the lamp, the plate-shaped light guide 40 can emit light more brightly.

[0076] Furthermore, since the inclination angle of the inclined plane 40s2, which is the surface located opposite the first end face 40c, of each of the multiple reflecting elements 40s is set to a value greater than the inclination angle of the inclined convex curved surface 40s1, which is the surface located on the first end face 40c side, the following effects can be obtained.

[0077] That is, in the plate-shaped light guide 40, a corner R is inevitably formed at the connection portion 40s2a between the rear surface 40b and the inclined plane 40s2, but the light totally reflected at this connection portion 40s2a can be totally reflected again at the inclined plane 40s2, thereby preventing the light emitted from the front surface 40a of the plate-shaped light guide 40 from traveling in a direction significantly inclined toward the first end face 40c.

[0078] Thus, according to this embodiment, in a vehicle lamp 10 equipped with a plate-shaped light guide 40, it is possible to prevent the light emitted from the light source that is incident on the plate-shaped light guide 40 from being emitted in an unintended direction.

[0079] As a result, the following specific effects can be obtained.

[0080] That is, the vehicle lamp 10 according to this embodiment is configured as a rear turn signal lamp mounted on the rear right side of the vehicle 100, and the first end face 40c of the plate-shaped light guide 40 is located on the front side of the vehicle, but in this type of vehicle lamp 10, if part of the light emitted from the plate-shaped light guide 40 is emitted in a direction close to the front of the vehicle, the resulting red light will give a sense of discomfort to drivers of nearby vehicles, etc. However, as described above, the light emitted from the front face 40a of the plate-shaped light guide 40 is not light that is directed in a direction significantly inclined toward the first end face 40c, so it is possible to prevent such a situation from occurring.

[0081] In particular, in the plate-shaped light guide 40 of this embodiment, each of the multiple reflective elements 40s is formed as a frustum-shaped recess, and these multiple reflective elements 40s are arranged alternately in the vertical and horizontal directions in multiple lattice-shaped areas A that are divided up in the vertical and horizontal directions (the required directions and directions perpendicular to these), so that the light emitted from the first light-emitting element 20 that is incident on the plate-shaped light guide 40 can easily be emitted from the plate-shaped light guide 40 toward the front of the lamp with approximately uniform brightness in two dimensions.

[0082] Furthermore, each of the multiple reflective elements 40s has a surface located on the first end face 40c side of the plate-shaped light guide 40 formed as an inclined convex curved surface 40s1, so that the light emitted from the first light-emitting element 20 that enters the plate-shaped light guide 40 can be totally reflected as light that is diffused in the vertical direction, thereby making the plate-shaped light guide 40 appear to glow with a more uniform brightness.

[0083] Furthermore, the vehicle lamp 10 according to this embodiment is configured so that light emitted from the first light-emitting element 20 is incident on the plate-shaped light guide 40, which has a horizontally elongated, approximately trapezoidal outer shape, from the first end face 40c, which has a narrow vertical width. Therefore, even though there is only one first light-emitting element 20, it is easily possible to make the plate-shaped light guide 40 appear to glow with approximately uniform brightness.

[0084] Furthermore, the vehicle lamp 10 of this embodiment has, as its light source, a second light-emitting element 30 arranged to cause light to enter the plate-shaped light guide 40 from the rear surface 40b side, and a lens portion 42 is formed in a portion of the plate-shaped light guide 40 that is located closer to the first end surface 40c than the multiple reflective elements 40s, and controls the emission of light from the second light-emitting element that has entered the plate-shaped light guide 40 toward the front of the lamp, thereby achieving the following effects.

[0085] That is, in the region of the plate light guide 40 closer to the first end face 40c, a portion of the light emitted from the first light-emitting element 20 and incident from the first end face 40c is not sufficiently totally reflected by the plurality of reflecting elements 40s, which tends to result in a relatively insufficient brightness. In contrast, in the present embodiment, a lens portion 42 that controls the emission of light from the second light-emitting element 30 that has entered the plate light guide 40 toward the front of the lamp is formed in a portion of the plate light guide 40 closer to the first end face 40c than the plurality of reflecting elements 40s, thereby making it possible to ensure sufficient brightness in the region of the plate light guide 40 closer to the first end face 40c.

[0086] In the above embodiment, the plate-shaped light guide 40 has been described as having an outer shape that is approximately horizontally elongated and trapezoidal, but it is also possible to configure it to have an outer shape other than this (for example, an outer shape that is horizontally elongated and rectangular or horizontally fan-shaped).

[0087] In the above embodiment, the inclination angle θ2 of the inclined plane 40s2 in each of the multiple reflecting elements 40s is exemplified as a value of approximately θ2=65°, but it is also possible to configure the inclination angle to be set to a value other than the example angle, as long as the angle is such that light totally reflected at the connection portion 40s2a of the inclined plane 40s2 is incident on the inclined plane 40s2.

[0088] In the above embodiment, the truncated cone-shaped recesses constituting each of the multiple reflective elements 40s have been described as having a surface shape based on a square pyramid, but it is also possible to adopt other surface shapes (for example, a surface shape based on a truncated pyramid other than a square pyramid, or a surface shape that is a cone or elliptical cone tilted to the right).

[0089] In the above embodiment, the inclined convex curved surface 40s1 is described as being composed of a portion of a conical surface, but it is also possible to adopt a surface shape other than this (for example, one composed of a portion of an elliptical cone, or one composed of a portion of a sphere or an elliptical sphere).

[0090] In the above embodiment, the vehicle lamp 10 is described as a rear turn signal lamp, but it may be configured as a lamp other than this.

[0091] Next, a modification of the above embodiment will be described.

[0092] First, a first modification of the above embodiment will be described.

[0093] FIG. 7 is a view similar to FIG. 4, showing a plate-shaped light guide 140 of a vehicle lamp according to this modified example.

[0094] As shown in FIG. 7, the basic configuration of the plate-shaped light guide 140 of this modification is the same as that of the above embodiment, but the configurations of the plurality of reflecting elements 140sA, 140sB, 140sC are different from those of the above embodiment.

[0095] That is, in the plate-shaped light guide 140 of this modified example, multiple reflective elements 140sA, 140sB, and 140sC are arranged two-dimensionally, and each of them is formed as a trapezoidal recess (specifically, a frustum-shaped recess), but it differs from the above embodiment in that the depths of the recesses are set to different values.

[0096] Specifically, the plurality of reflecting elements 140sA, 140sB, and 140sC are formed as trapezoidal recesses that are deeper as they are positioned further away from the first end face (not shown) of the plate-like light guide 140. Note that although only three reflecting elements 140sA, 140sB, and 140sC are shown in Fig. 7, the same applies to the other reflecting elements.

[0097] In this modified example, the light emitted from the first light-emitting element (not shown) that enters the plate-shaped light guide 140 can be totally reflected not only by the front surface 140a and rear surface 140b of the plate-shaped light guide 140 but also by the bottom surfaces 140sA0, 140sB0, and 140sC0 of the trapezoidal recess, thereby improving the light guide efficiency.

[0098] Furthermore, by adopting the configuration of this modified example, the amount of light that is totally reflected at each of the multiple reflecting elements 140sA, 140sB, and 140sC can be maintained at an approximately constant value regardless of the distance from the first end face, thereby making the plate-shaped light guide 140 appear to glow with a more uniform brightness.

[0099] Next, a second modification of the above embodiment will be described.

[0100] Fig. 8 shows a plate-shaped light guide 240 of a vehicle lamp according to this modified example, and is substantially the same as Fig. 4. Note that Fig. 8 shows the plate-shaped light guide 240 in a cross-sectional perspective view.

[0101] As shown in FIG. 8, the basic configuration of a plate-shaped light guide 240 of this modification is the same as that of the above embodiment, but the configuration of the plurality of reflecting elements 240s is different from that of the above embodiment.

[0102] That is, the plate-shaped light guide 240 of this modification also has a flat front surface 240a, and a rear surface 240b on which a plurality of reflecting elements 240s are formed, each of which is formed as a trapezoidal recess.

[0103] However, in this modified example, each of the multiple reflective elements 240s is formed as a trapezoidal recess that extends in the vertical direction while maintaining its trapezoidal horizontal cross-sectional shape, rather than as a frustum-shaped recess, and these multiple reflective elements 240s are arranged at equal intervals in the horizontal direction.

[0104] In this modified example, the light emitted from the first light-emitting element (not shown) that enters the plate-shaped light guide 240 can be totally reflected not only by the front surface 240a and rear surface 240b of the plate-shaped light guide 240 but also by the bottom surface 240s0 of the trapezoidal recess, thereby improving the light guide efficiency.

[0105] Furthermore, by configuring each of the multiple reflective elements 240s as a trapezoidal recess having a trapezoidal horizontal cross-sectional shape extending in the vertical direction, as in the plate-shaped light guide 240 of this modified example, the configuration of the plate-shaped light guide 240 can be simplified and its costs can be reduced.

[0106] Next, a third modification of the above embodiment will be described.

[0107] FIG. 9 is a view similar to FIG. 4, showing a plate-shaped light guide 340 of a vehicle lamp according to this modified example.

[0108] As shown in FIG. 9, the basic configuration of a plate-shaped light guide 340 of this modification is the same as that of the above embodiment, but the positioning of the plurality of reflecting elements 340s differs from that of the above embodiment.

[0109] That is, the plate light guide 40 of the above embodiment is configured such that each of the plurality of reflecting elements 40s is formed as a frustum-shaped recess on its rear surface 40b, but the plate light guide 340 of this modified example has a rear surface 340b of the plate light guide 340 located on the same plane as the bottom surfaces 40s0 of each of the plurality of reflecting elements 40s in the plate light guide 40 of the above embodiment, and also has a tip surface 340s0 of each of the plurality of reflecting elements 340s located on the same plane as the rear surface 40b of the plate light guide 40 of the above embodiment. As a result, in the plate light guide 340 of this modified example, the portions of the plate light guide 40 of the above embodiment located between the plurality of reflecting elements 40s (i.e., the portions formed as frustum-shaped convex portions) are configured as the plurality of reflecting elements 340s.

[0110] Specifically, each of the plurality of reflecting elements 340s has a surface (i.e., the surface located on the left side) located on the first end face (not shown) side of the plate-shaped light guide 340 that is configured as an inclined flat surface 340s1, and a surface (i.e., the surface located on the right side) located on the second end face (not shown) side that is configured as an inclined concave surface 340s2. In this case, the inclined concave surface 340s2 is formed at an inclination angle θ1, and the inclined flat surface 340s1 is formed at a larger inclination angle θ2 (θ2>θ1).

[0111] As described above, in this modified example, the shape of the plate-shaped light guide 340 itself is the same as that of the plate-shaped light guide 40 in the above embodiment, and only the positioning of the multiple reflective elements 340s differs from that in the above embodiment, so its optical function is exactly the same as in the case of this modified example.

[0112] Therefore, even when the configuration of this modified example is adopted, the same effects as those of the above embodiment can be obtained.

[0113] When the configuration of this modified example is adopted, each of the multiple reflecting elements 340s can be configured to have a frustum-shaped convex portion that is higher the farther the reflecting element 340s is positioned from the first end face (not shown).

[0114] Furthermore, similarly to the case of this modified example, with respect to the plate-shaped light guides 140, 240 of the first and second modified examples described above, it is also possible to configure the portions formed as frustum-shaped convex portions (or trapezoidal convex portions) between the multiple reflecting elements 140s, 240s as multiple reflecting elements.

[0115] It should be noted that the numerical values ​​shown as the specifications in the above embodiment and its modified examples are merely examples, and it goes without saying that these may be set to different values ​​as appropriate.

[0116] Furthermore, the present invention is not limited to the configurations described in the above embodiment and its modifications, and various other modified configurations can be adopted. [Explanation of symbols]

[0117] 10L, 10R vehicle lighting fixtures 12 Lamp body 14 Translucent cover 20 First light-emitting element (light source) 30 Second light-emitting element (light source) 22, 32 board 40, 140, 240, 340 Plate-shaped light guide 40a, 140a, 240a front 40b, 140b, 240b, 340b rear 40c 1st end face 40d 2nd end face 40s, 140sA, 140sB, 140sC, 240s, 340s reflective elements 40s0, 140sA0, 140sB0, 140sC0, 240s0 Bottom 40s1 Inclined convex curved surface (surface located on the first end face side) 40s1a, 40s2a, 40s3a, 40s4a connection part 40s2 Inclined plane (surface located opposite the first end face) 40s3, 40s4 inclined plane 340s0 Tip surface 340s1 Inclined plane (surface located on the first end face side) 340s2 Inclined concave surface (surface located opposite the first end face) 42 Lens section 50 Extension Panel 50a opening 50b flange 52 Reflective surface 100 vehicles Area A L straight line α, β angles θ1, θ2 Tilt angle

Claims

1. A vehicle lamp including a light source and a plate-shaped light guide, The plate-shaped light guide is disposed so as to extend in a required direction intersecting with the front-rear direction of the lamp, the light source includes a first light-emitting element arranged to cause light to be incident on the plate-shaped light guide from a first end surface of the plate-shaped light guide in the required direction, a plurality of reflecting elements are formed on the rear surface of the plate-shaped light guide, the reflecting elements totally reflecting the light from the first light-emitting element that has entered the plate-shaped light guide toward the front of the lamp; Each of the plurality of reflective elements is formed as a trapezoidal recess having a trapezoidal cross-sectional shape, and the inclination angle of the surface located opposite the first end face is set to a value larger than the inclination angle of the surface located on the first end face side.

2. Each of the plurality of reflective elements is formed as a frustum-shaped recess, 2. The vehicle lamp according to claim 1, wherein the plurality of reflective elements are arranged alternately in the required direction and a direction perpendicular to the required direction in a plurality of grid-like regions divided in the required direction and a direction perpendicular to the required direction.

3. 3. The vehicle lamp according to claim 1, wherein each of the plurality of reflecting elements has a surface located on the first end face side that is formed into a convex curved shape.

4. 3. The vehicle lamp according to claim 1, wherein the plurality of reflecting elements are formed as trapezoidal recesses that are deeper as the reflecting elements are positioned farther from the first end face.

5. The light source includes a second light-emitting element arranged to emit light from a rear surface side of the plate-shaped light guide, 3. A vehicle lamp according to claim 1, wherein a lens portion is formed in a portion of the plate-shaped light guide that is located closer to the first end face than the plurality of reflective elements, and that controls the emission of light from the second light-emitting element that is incident on the plate-shaped light guide toward the front of the lamp.

6. A vehicle lamp including a light source and a plate-shaped light guide, The plate-shaped light guide is disposed so as to extend in a required direction intersecting with the front-rear direction of the lamp, the light source includes a first light-emitting element arranged to cause light to be incident on the plate-shaped light guide from a first end surface of the plate-shaped light guide in the required direction, a plurality of reflecting elements are formed on the rear surface of the plate-shaped light guide, the reflecting elements totally reflecting the light from the first light-emitting element that has entered the plate-shaped light guide toward the front of the lamp; Each of the plurality of reflective elements is formed as a trapezoidal convex portion having a trapezoidal cross-sectional shape, and the inclination angle of the surface located on the first end face side is set to a value larger than the inclination angle of the surface located on the opposite side from the first end face.

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