Vehicle lamp

Abstract

A vehicle lamp (1) comprises a light source (20), and a plate-shaped light guide (30) which has an end face (32) on which light from the light source (20) is incident and which guides the light incident from the end face (32) to a side opposite from the end face (32). The light guide (30) comprises a light entrance portion (40) which includes the end face (32), and a light emitting portion (50) which is connected to the side of the light entrance portion (40) opposite from the end face (32). The light entrance portion (40) has a plurality of light entrance portion steps (45) which are provided on at least one main surface of the light entrance portion (40) and which internally reflect light. The light emitting portion (50) has a plurality of light emitting portion steps (55) which have a shape different from that of the light entrance portion steps (45) and which cause light propagating from the light entrance portion (40) to be emitted from one main surface (52) of the light emitting portion (50). The amount of light per unit area emitted from the main surface (52) of the light emitting portion (50) is greater than the amount of light per unit area emitted from the main surface (42) of the light entrance portion (40) on the side of the main surface (52) of the light emitting portion (50).

Description

Vehicle lighting fixtures

[0001] The present invention relates to a vehicle lamp.

[0002] 2. Description of the Related Art Some vehicle lamps include a light source and a plate-shaped light guide that guides light from the light source. Patent Document 1 listed below discloses such a vehicle lamp.

[0003] The vehicle lamp disclosed in Patent Document 1 below includes a light source and a plate-shaped light guide having an end face facing the light source and on which light from the light source is incident, and guiding the light incident from the end face to the opposite side of the end face. The light guide includes a light entrance portion including the end face and a light exit portion connected to the opposite side of the end face of the light entrance portion. The light exit portion has a plurality of light exit portion steps that internally reflect light propagating from the light entrance portion so that the light exits from one main surface of the light exit portion. Therefore, light incident from the end face propagates from the light entrance portion to the light exit portion, is internally reflected by the light exit portion steps, and exits from one main surface of the light exit portion.

[0004] JP 2013-16386 A

[0005] In such vehicle lamps, much of the light is internally reflected by both principal surfaces of the light entrance portion and propagates to the light exit portion. When the distance of the light entrance portion is short, the number of internal reflections of light at the principal surfaces is small, and the propagation direction of light propagating through the light entrance portion is less likely to vary. This can lead to unevenness in the amount of light components incident on one principal surface of the light exit portion among multiple light exit portion steps, resulting in an uneven appearance. Methods for suppressing such unevenness include, for example, lengthening the distance of the light entrance portion or bending the light entrance portion. However, due to the demand for greater flexibility in light source placement, it may be difficult to adopt these methods.

[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a vehicle lamp that can suppress unevenness in appearance while increasing the degree of freedom in arranging light sources.

[0007] In order to achieve the above object, the vehicle lamp of the present invention comprises a light source and a plate-shaped light guide having an end face facing the light source and into which light from the light source is incident, and guiding the light incident from the end face to the opposite side to the end face side, the light guide comprising a light entrance portion including the end face and a light exit portion connected to the opposite side of the end face side of the light entrance portion, the light entrance portion being provided on at least one main surface of the light entrance portion and having a plurality of light entrance portion steps that internally reflect the light incident from the end face, the light exit portion having a shape different from the light entrance portion steps and having a plurality of light exit portion steps that cause light propagating from the light entrance portion to exit from one main surface of the light exit portion, and the amount of light per unit area that exits from the one main surface of the light exit portion is greater than the amount of light per unit area that exits from one main surface of the light entrance portion that is closer to the one main surface side of the light exit portion.

[0008] In this vehicle lamp, the light entrance portion has multiple light entrance step portions that internally reflect light incident from the end surface. Therefore, even without increasing the distance of the light entrance portion or bending the light entrance portion, the internal reflection of light at the main surface of the light entrance portion can become irregular, compared to when the light entrance step is not formed, which can cause variations in the propagation direction of light propagating through the light entrance portion. Therefore, compared to the above case, the multiple light exit portion step portions can reduce variations in the amount of light components incident to be emitted from one main surface of the light exit portion, thereby reducing variations in appearance. Therefore, compared to the above case, variations in appearance can be reduced while increasing the degree of freedom in light source placement.

[0009] The plurality of light entrance steps may be provided on both of the main surfaces of the light entrance portion.

[0010] With this configuration, there can be more variation in the propagation direction of light propagating through the light entrance section, and unevenness in appearance can be more effectively suppressed, compared to when a light entrance section step is provided on only one of the main surfaces of the light entrance section.

[0011] The plurality of light entrance steps may include a plurality of convex cylindrical steps extending from the end face side toward the light exit side and arranged in parallel to one another.

[0012] With this configuration, the propagation direction of light propagating through the light entrance portion can be made more likely to vary in the width direction of the light entrance portion.

[0013] The interval between adjacent light emitting steps may be narrower than the interval between adjacent convex cylindrical steps.

[0014] The light source may have at least one emission surface from which light is emitted, and the interval between adjacent convex cylindrical steps may be equal to or less than the width of the emission surface in the arrangement direction of the plurality of convex cylindrical steps.

[0015] The plurality of light entrance steps may include a concave cylindrical step located between adjacent convex cylindrical steps and extending from the end face side toward the light exit side.

[0016] According to this configuration, the convex cylindrical steps and the concave cylindrical steps can make it easier for the propagation direction of light propagating through the light entrance portion to vary in the width direction of the light entrance portion.

[0017] The width of the convex cylindrical step may be wider than the width of the concave cylindrical step, or the width of the convex cylindrical step may be narrower than the width of the concave cylindrical step.

[0018] The plurality of light entrance steps may include a plurality of concave cylindrical steps extending from the end face side toward the light exit side and arranged in parallel to one another.

[0019] With this configuration, the propagation direction of light propagating through the light entrance portion can be made more likely to vary in the width direction of the light entrance portion.

[0020] The plurality of light entrance steps may include a plurality of convex fisheye steps.

[0021] The fisheye step can cause the propagation direction of light to vary in the width direction and thickness direction of the light entrance section. Therefore, with this configuration, compared to when the light entrance section step is a convex cylindrical step or a concave cylindrical step, it is possible to more easily cause variation in the propagation direction of light propagating through the light entrance section, and for example, even if the length of the light entrance section is shortened, it is possible to suppress unevenness in appearance and increase the degree of freedom in arranging the light source.

[0022] The main surface of the light entrance portion on which the fish-eye steps are provided may have a recess between adjacent fish-eye steps.

[0023] Compared to when the space between adjacent fisheye steps is flat, this makes it easier for the propagation direction of light propagating through the light entrance section to vary, and for example, even if the length of the light entrance section is shortened, unevenness in appearance can be suppressed, and the freedom of light source placement can be increased.

[0024] The vehicle lamp may be a marker lamp.

[0025] As described above, according to the present invention, it is possible to provide a vehicle lamp that can increase the degree of freedom in arranging light sources while suppressing unevenness in appearance.

[0026] Fig. 1 is a horizontal cross-sectional view of a vehicle lamp according to a first embodiment of the present invention. Fig. 2 is a view of a light source and a light guide according to the first embodiment, seen from behind. Fig. 3 is a perspective view of the light guide, seen from diagonally above. Fig. 4 is a vertical cross-sectional view of a light entrance portion. Fig. 5 is a view of a light source and a light guide according to a second embodiment, seen from behind. Fig. 6 is a vertical cross-sectional view of a light entrance portion according to the second embodiment. Fig. 7 is a vertical cross-sectional view of a light entrance portion in a modified example.

[0027] Below, embodiments for carrying out a vehicle lamp according to the present invention are illustrated with reference to the accompanying drawings. The embodiments illustrated below are intended to facilitate understanding of the present invention and are not intended to limit the present invention. The present invention can be modified and improved within the scope of the claims without departing from the spirit thereof. Furthermore, the present invention may also be realized by appropriately combining the components in each of the embodiments illustrated below. Note that in the drawings referred to below, the dimensions of each component may be changed to facilitate understanding.

[0028] <First embodiment> Fig. 1 is a horizontal cross-sectional view of a vehicle lamp according to a first embodiment of the present invention. The vehicle lamp 1 of this embodiment is a tail lamp, which is a type of marker lamp for four-wheeled motor vehicles. Such tail lamps are generally provided on the left and right sides of the rear of the vehicle. In this specification, "right" means the right side in the forward direction of the vehicle, and "left" means the left side in the forward direction of the vehicle. The left and right tail lamps have the same configuration except that their shapes are roughly symmetrical in the left-right direction. Therefore, the following description will focus on the vehicle lamp 1 that is the left tail lamp. In Fig. 1, the upper side corresponds to the front side of the vehicle, and the lower side corresponds to the rear side of the vehicle.

[0029] As shown in FIG. 1, the vehicle lamp 1 of this embodiment mainly comprises a housing 10, a light source 20, and a light guide 30 that guides light from the light source 20.

[0030] The housing 10 has a lamp housing 11 and a light-transmitting outer cover 12. The rear of the lamp housing 11 is open, and the outer cover 12 is fixed to the lamp housing 11 so as to close the opening. A light source 20 and a light guide 30 are housed in the space formed by the lamp housing 11 and the outer cover 12.

[0031] Fig. 2 is a rear view of the light source 20 and the light guide 30 according to this embodiment. As shown in Figs. 1 and 2, the light source 20 according to this embodiment includes a plurality of light-emitting elements 22. In this embodiment, the light-emitting elements 22 emit red light when the vehicle headlights are turned on. The light-emitting elements 22 according to this embodiment are light-emitting diodes (LEDs) that emit light with a Lambertian light distribution. However, the light-emitting elements 22 are not limited thereto.

[0032] The light guide 30 of this embodiment is a translucent plate-like member, and is arranged with one main surface facing rearward. The light guide 30 has an outer shape that is rectangular and elongated in the left-right direction. The light-emitting elements 22 are arranged so that their light-emitting surfaces 24 face an end face 32, which is the right end of the light guide 30, and are aligned at approximately equal intervals in the up-down direction along the end face 32. Light emitted from the light-emitting elements 22 enters the light guide 30 from the end face 32. In this embodiment, the end face 32 is a flat surface that is approximately parallel to the thickness direction of the light guide 30.

[0033] The light guide 30 is composed of a light entrance section 40 including an end face 32, and a light exit section 50 connected to the side of the light entrance section 40 opposite the end face 32. In other words, the light entrance section 40 is the portion of the light guide 30 on the end face 32 side, and the light exit section 50 is the portion of the light guide 30 opposite the end face 32. Examples of materials that form the light guide 30 include transparent resin and glass. In this embodiment, the light entrance section 40 and the light exit section 50 are integrated.

[0034] FIG. 3 is a perspective view of the light guide 30 viewed from diagonally above. FIG. 4 is a vertical cross-sectional view of the light entrance section 40. As shown in FIGS. 3 and 4 , a plurality of light entrance steps 45 are provided on both the rear main surface 42 and the front main surface 44 of the light entrance section 40. The plurality of light entrance steps 45 on each of the main surfaces 42, 44 includes a plurality of convex cylindrical steps 46 and a plurality of concave cylindrical steps 47. The plurality of convex cylindrical steps 46 are steps formed by curved surfaces whose cross sections perpendicular to the extension direction are convexly curved arcs, and extend from the end face 32 side toward the light exit section 50 side and are arranged in parallel. The plurality of concave cylindrical steps 47 are steps formed by curved surfaces whose cross sections perpendicular to the extension direction are concavely curved arcs, and extend from the end face 32 side toward the light exit section 50 side. In this embodiment, the concave cylindrical steps 47 are located between adjacent convex cylindrical steps 46. Therefore, the multiple concave cylindrical steps 47 are parallel to one another. Adjacent convex cylindrical steps 46 and concave cylindrical steps 47 are connected so that no bends are formed. The convex cylindrical steps 46 and concave cylindrical steps 47 extend from the end of the light entrance portion 40 on the end face 32 side to the end of the light exit portion 50 side, and the main surfaces 42, 44 are made up of the convex cylindrical steps 46 and concave cylindrical steps 47.

[0035] In this embodiment, the width 46W of the convex cylindrical steps 46 in the arrangement direction is wider than the width 47W of the concave cylindrical steps 47 in the arrangement direction of the convex cylindrical steps 46. Furthermore, the spacing 46D between adjacent convex cylindrical steps 46 is equal to or less than the width 24W of the light-emitting surface 24 of the light-emitting element 22 in the arrangement direction of the multiple convex cylindrical steps 46. The spacing 46D between the convex cylindrical steps 46 is the distance between the centers 46C of the convex cylindrical steps 46. The width 24W of the light-emitting surface 24 can be understood as the width of the light-emitting surface 24 in a direction parallel to the main surface 42, and the spacing 46D may exceed the width 24W. The boundary between the convex cylindrical step 46 and the concave cylindrical step 47 is an inflection point in the curve representing the convex cylindrical step 46 and the concave cylindrical step 47 in cross section.

[0036] Furthermore, the center 46C of the convex cylindrical step 46 on the main surface 42 overlaps with the center 46C of the convex cylindrical step 46 on the main surface 44 in the thickness direction of the light entrance portion 40. The center 47C of the concave cylindrical step 47 on the main surface 42 overlaps with the center 47C of the concave cylindrical step 47 on the main surface 44 in the thickness direction of the light entrance portion 40.

[0037] As shown in FIGS. 2 and 3 , in this embodiment, the rear main surface 52 of the light emitting portion 50 is flat, and multiple light emitting portion steps 55 having a different shape from the light input step 45 are provided on the main surface 52. The light emitting portion steps 55 have a concave dot structure recessed inward from the main surface 52 of the light emitting portion 50. The multiple light emitting portion steps 55 are arranged in a matrix pattern, forming rows in the vertical and horizontal directions. The spacing 55D1 between adjacent light emitting portion steps 55 in the vertical direction is generally the same as the spacing 55D2 between adjacent light emitting portion steps 55 in the horizontal direction. Note that the spacings 55D1 and 55D2 between the light emitting portion steps 55 are the distance between the centers of the light emitting portion steps 55. These spacings 55D1 and 55D2 are narrower than the spacing 46D between adjacent convex cylindrical steps 46 and, in this embodiment, are approximately half of the spacing 46D. Furthermore, the arrangement of the plurality of light emitting portion steps 55 is not limited, and for example, the plurality of light emitting portion steps 55 may be arranged in a staggered pattern. Note that the front main surface 54 of the light emitting portion 50 is a flat surface without any steps.

[0038] Next, the operation of the vehicle lamp 1 of this embodiment will be described.

[0039] When the vehicle headlights are turned on, the light-emitting element 22 of the light source 20 emits red light. The light from the light source 20 enters the light entrance portion 40 from the end face 32 of the light guide 30, propagates through the light entrance portion 40 toward the light exit portion 50, and enters the light exit portion 50. Most of the light propagating through the light entrance portion 40 travels toward the light exit portion 50 after repeated internal reflections on the main surfaces 42, 44 of the light entrance portion 40. In this embodiment, the main surfaces 42, 44 are made up of convex cylindrical steps 46 and concave cylindrical steps 47, and therefore the convex cylindrical steps 46 and concave cylindrical steps 47 internally reflect light. In other words, the convex cylindrical steps 46 and concave cylindrical steps 47, which are the light entrance portion steps 45, are steps that internally reflect light incident from the end face 32.

[0040] Of the light propagating through the light exit portion 50, light that enters the light exit portion step 55 provided on the main surface 52 is emitted rearward from the light exit portion step 55. In other words, the light exit portion step 55 is a step that causes light propagating from the light entrance portion 40 to exit from the main surface 52 of the light exit portion 50. In this way, the light that exits rearward from the main surface 52 of the light exit portion 50 is irradiated toward the rear of the vehicle via the outer cover 12. In this way, the vehicle lamp 1 of this embodiment functions as a tail lamp when the vehicle's headlights are turned on. Note that light also leaks from the main surface 42 of the light entrance portion 40, but the amount of light per unit area that exits from the main surface 52 of the light exit portion 50 is greater than the amount of light per unit area that exits from the main surface 42 of the light entrance portion 40. That is, the shapes of the convex cylindrical steps 46, the concave cylindrical steps 47 and the light emitting step 55 are adjusted so that the amount of light emitted is as described above.

[0041] As described above, in the vehicle lamp 1 of this embodiment, the light guide 30 is composed of a light entrance portion 40 including an end face 32 and a light exit portion 50 connected to the side of the light entrance portion 40 opposite the end face 32. The light entrance portion 40 has a plurality of light entrance step 45 provided on the main surfaces 42, 44 of the light entrance portion 40, which internally reflects light incident from the end face 32. The light exit portion 50 has a shape different from the light entrance step 45 and has a plurality of light exit step 55 that causes light propagating from the light entrance portion 40 to exit from the main surface 52 of the light exit portion 50. According to the vehicle lamp 1 of this embodiment, even without increasing the distance of the light entrance portion 40 or bending the light entrance portion 40, the internal reflection of light at the main surfaces 42, 44 can become irregular compared to a case in which the light entrance step 45 is not formed, and variation in the propagation direction of light propagating through the light entrance portion 40 can occur. Therefore, according to the vehicle lamp 1 of this embodiment, compared to the above case, it is possible to make it less likely that unevenness will occur in the amount of light components that enter the plurality of light exit portion steps 55 to be emitted from the main surface 52 of the light exit portion 50, and it is possible to suppress unevenness in appearance. Therefore, according to the vehicle lamp 1 of this embodiment, it is possible to suppress unevenness in appearance while increasing the degree of freedom in arranging the light source 20, compared to the above case. Note that the distance of the light entrance portion 40 is the length of the light entrance portion 40 in the direction from the end face 32 side toward the light exit portion 50 side, and in this embodiment it is the length of the light entrance portion 40 in the left-right direction.

[0042] In the vehicle lamp 1 of this embodiment, the plurality of light entrance steps 45 are provided on both main surfaces 42, 44 of the light entrance portion 40. Therefore, according to the vehicle lamp 1 of this embodiment, more variation in the propagation direction of light propagating through the light entrance portion 40 can be produced, and unevenness in appearance can be further suppressed, compared to when the light entrance steps 45 are provided on only one main surface of the light entrance portion 40. Note that the light entrance steps 45 may be provided only on the main surface 42 located on the side of the main surface 52 from which the light exit portion 50 emits light, or may be provided only on the main surface 44 located opposite the main surface 52.

[0043] In the vehicle lamp 1 of this embodiment, the plurality of light entrance steps 45 include a plurality of parallel convex cylindrical steps 46 that extend from the end face 32 side toward the light exit portion 50 side. Therefore, according to the vehicle lamp 1 of this embodiment, the propagation direction of light propagating through the light entrance portion 40 can be made more likely to vary in the width direction of the light entrance portion 40. The width direction of the light entrance portion 40 is the direction from the end face 32 side toward the light exit portion 50 side and the direction perpendicular to the thickness direction of the light entrance portion 40, which is the up-down direction in this embodiment.

[0044] In the vehicle lamp 1 of this embodiment, the multiple light entrance steps 45 include concave cylindrical steps 47 that are located between adjacent convex cylindrical steps 46 and extend from the end face 32 toward the light exit portion 50. Therefore, according to the vehicle lamp 1 of this embodiment, the convex cylindrical steps 46 and the concave cylindrical steps 47 can make it easier for the propagation direction of light propagating through the light entrance portion 40 to vary in the width direction of the light entrance portion 40. Furthermore, the concave cylindrical steps 47 can make the propagation direction of light more easily vary in the width direction of the light entrance portion 40 than the convex cylindrical steps 46. Therefore, according to the vehicle lamp 1 of this embodiment, it is easier for the propagation direction of light propagating through the light entrance portion 40 to vary compared to when the multiple light entrance steps 45 do not include the concave cylindrical steps 47. For example, even if the length of the light entrance portion 40 is shortened, unevenness in appearance can be suppressed, and the degree of freedom in arranging the light source 20 can be increased.

[0045] Second Embodiment Next, a second embodiment will be described in detail. Note that components that are the same as or equivalent to those in the first embodiment will be assigned the same reference numerals unless otherwise specified, and duplicate descriptions will be omitted.

[0046] FIG. 5 is a rear view of the light source 20 and the light guide 30 according to this embodiment. FIG. 6 is a vertical cross-sectional view of the light entrance portion 40 according to this embodiment. As shown in FIGS. 5 and 6 , the vehicle lamp 1 according to this embodiment differs from the light entrance portion 45 according to the first embodiment mainly in the configuration of the light entrance portion step 45. The light entrance portion step 45 according to this embodiment is composed of a plurality of convex fisheye steps 48, instead of the convex cylindrical step 46 and the concave cylindrical step 47 according to the first embodiment. The plurality of convex fisheye steps 48 are steps formed by a convex curved surface that is curved like a partial spherical surface, and are arranged in a matrix pattern that forms rows in the vertical and horizontal directions. The sizes of the plurality of fisheye steps 48 are generally the same. Note that the arrangement of the convex fisheye steps 48 is not limited; for example, the convex fisheye steps 48 may be arranged in a houndstooth pattern.

[0047] The interval 48D1 between adjacent fisheye steps 48 in the up-down direction and the interval 48D2 between adjacent fisheye steps 48 in the left-right direction are approximately the same. Note that the intervals 48D1 and 48D2 between the fisheye steps 48 are the distance between the centers of the fisheye steps 48. These intervals 48D1 and 48D2 are equal to or less than the width 24W of the emission surface 24 of the light-emitting element 22 in the direction parallel to the main surface 42. Note that the intervals 48D1 and 48D2 may be different or may be greater than the width 24W.

[0048] Furthermore, the center 48C of the fish-eye step 48 on the main surface 42 overlaps with the center 48C of the fish-eye step 48 on the main surface 44 in the thickness direction of the light entrance portion 40 .

[0049] Furthermore, between adjacent fisheye steps 48 on the main surfaces 42, 44, there is a recessed depression 49, and the shape of the depression 49 in a cross section that intersects adjacent fisheye steps 48 is arc-shaped. Furthermore, in the depression 49, the center of the area surrounded by four fisheye steps 48 is the deepest. The main surfaces 42, 44 are made up of a plurality of fisheye steps 48 and depressions 49.

[0050] In this embodiment, most of the light propagating through the light entrance portion 40 and incident on the fisheye step 48 is internally reflected by the fisheye step 48 toward the light exit portion 50. In other words, the fisheye step 48 is a step that internally reflects the light propagating through the light entrance portion 40.

[0051] According to the vehicle lamp 1 of this embodiment, as in the first embodiment, it is possible to increase the freedom of arrangement of the light source 20 while suppressing unevenness in appearance compared to when the fisheye step 48, which is the light entrance step 45, is not formed.

[0052] The fisheye step 48 can cause the propagation direction of light to vary in the width direction and thickness direction of the light entrance portion 40. Therefore, according to the vehicle lamp 1 of this embodiment, the propagation direction of light propagating through the light entrance portion 40 can be more easily varied than when the light entrance step 45 is a convex cylindrical step 46 or a concave cylindrical step 47. Therefore, according to the vehicle lamp 1 of this embodiment, even if the length of the light entrance portion 40 is shortened, for example, it is possible to suppress unevenness in appearance and increase the degree of freedom in arranging the light source 20.

[0053] Although the present invention has been described above using the above-mentioned embodiments as examples, the present invention is not limited to these.

[0054] For example, the first embodiment described above uses the light entrance step 45 including the convex cylindrical step 46 and the concave cylindrical step 47, while the second embodiment described uses the light entrance step 45 including the fish-eye step 48. However, the light entrance step 45 is not limited to this configuration as long as it internally reflects light incident from the end face 32 and the amount of light per unit area exiting from the main surface 52 of the light exit portion 50 is greater than the amount of light per unit area exiting from the main surface 42 closest to the main surface 52, one of the main surfaces 42, 44 of the light entrance portion 40. For example, the multiple light entrance steps 45 may be composed only of multiple convex cylindrical steps 46 or only of multiple concave cylindrical steps 47. Alternatively, the multiple light entrance steps 45 may include multiple convex cylindrical steps 46, multiple concave cylindrical steps 47, and multiple fish-eye steps 48.

[0055] In the first embodiment, an example has been described in which the adjacent convex cylindrical step 46 and the adjacent concave cylindrical step 47 are connected to each other. However, the adjacent convex cylindrical step 46 and the adjacent concave cylindrical step 47 may be spaced apart from each other.

[0056] In the first embodiment, the width 46W of the convex cylindrical step 46 is wider than the width 47W of the concave cylindrical step 47. However, as shown in FIG. 7 , the width 46W may be narrower than the width 47W. As described above, the concave cylindrical step 47 can make the light propagation direction more likely to vary in the width direction of the light entrance portion 40 than the convex cylindrical step 46. Therefore, according to the vehicle lamp 1 of this modified example, the propagation direction of light propagating through the light entrance portion 40 can be more easily varied than when the width 46W is wider than the width 47W. For example, even if the length of the light entrance portion 40 is shortened, unevenness in appearance can be suppressed and the degree of freedom in arranging the light source 20 can be increased.

[0057] In the first embodiment, an example has been described in which the centers 46C of the convex cylindrical steps 46 on the main surface 42 overlap with the centers 46C of the convex cylindrical steps 46 on the main surface 44 in the thickness direction of the light entrance section 40, and the centers 47C of the concave cylindrical steps 47 on the main surface 42 overlap with the centers 47C of the concave cylindrical steps 47 on the main surface 44 in the thickness direction of the light entrance section 40. However, the arrangements of the convex cylindrical steps 46 and the concave cylindrical steps 47 on the main surface 42 and the main surface 44 may be shifted in the arrangement direction. In other words, the arrangement phases of the convex cylindrical steps 46 on the main surface 42 and the main surface 44 may be different. For example, the center 46C of the convex cylindrical step 46 on the main surface 42 may overlap with the concave cylindrical step 47 in the thickness direction of the light entrance section 40, or the center 46C may overlap with the center 47C in the thickness direction of the light entrance section 40.

[0058] Furthermore, the width 46W of the convex cylindrical step 46 on the main surface 42 may be different from the width 46W of the convex cylindrical step 46 on the main surface 44. Furthermore, the widths 46W of two or more convex cylindrical steps 46 on the main surface 42 may be different from each other, and the widths 47W of two or more concave cylindrical steps 47 on the main surface 42 may be different from each other. Furthermore, the widths 46W of two or more convex cylindrical steps 46 on the main surface 44 may be different from each other, and the widths 47W of two or more concave cylindrical steps 47 on the main surface 44 may be different from each other.

[0059] Furthermore, in the second embodiment, the center 48C of the fisheye step 48 on the main surface 42 does not have to overlap with the center 48C of the fisheye step 48 on the main surface 44 in the thickness direction of the light entrance section 40. Furthermore, the sizes of two or more fisheye steps 48 on the main surface 42 may be different from each other, and the sizes of two or more fisheye steps 48 on the main surface 44 may be different from each other.

[0060] Furthermore, in the above embodiment, the end face 32 is flat, but this is not limiting. For example, the end face 32 may be a curved surface that is concavely curved toward the inside of the light guide 30 and has an arc-shaped cross section perpendicular to the end face 32 and the main surface 42. With this configuration, light incident on the end face 32 from the light source 20 may be more likely to be directed toward the main surface 42 or the main surface 44 of the light entrance portion 40. This may make it easier for the propagation direction of light propagating through the light entrance portion 40 to vary. Furthermore, the end face 32 may be a curved surface that is convexly curved toward the outside of the light guide 30 and has an arc-shaped cross section perpendicular to the end face 32 and the main surface 42.

[0061] In the above embodiment, the light-emitting step 55 has been described as having a recessed dot structure. However, the light-emitting step 55 is not limited to a specific shape as long as it has a shape different from that of the light-entering step 45 and is configured to cause light propagating from the light-entering portion 40 to exit from the main surface 52 of the light-emitting portion 50. For example, the light-emitting step 55 may be a step provided on the main surface 54 that internally reflects light propagating from the light-entering portion 40 toward the main surface 52 and causes the light to exit from the main surface 52. The plurality of light-emitting steps 55 may include a step provided on the main surface 54 that internally reflects light propagating from the light-entering portion 40 toward the main surface 52 and causes the light to exit from the main surface 52, and another step provided on the main surface 52 that causes the light propagating from the light-entering portion 40 to exit from the main surface 52. Furthermore, when a plurality of light exit portion steps 55 are provided on one of the main surfaces 52 and 54, the light entrance portion step 45 may be provided only on the main surface of the main surface 42 or 44 that is located on the main surface side on which the light exit portion step 55 is provided, and for example, in the first embodiment, the light entrance portion step 45 may be provided only on the main surface of the main surface 42 or 44 that is located on the side opposite to the main surface side on which the light exit portion step 55 is provided, and for example, in the first embodiment, the light entrance portion step 45 may be provided only on the main surface 44.

[0062] In the second embodiment, the recessed portion 49 is formed between adjacent fisheye steps 48 on the main surfaces 42, 44, but this is not limited thereto. For example, the recessed portion 49 may be formed between adjacent fisheye steps 48 on the main surfaces 42, 44.

[0063] Furthermore, in the above embodiment, the light source 20 includes a plurality of light emitting elements 22, but the light source 20 is not limited to this.

[0064] In the above embodiment, the light source 20 emits red light. However, the color of the light emitted by the light source 20 is not limited. For example, the color of the light may be white. In this case, the light guide 30 is made of, for example, a red transparent resin or glass.

[0065] In the above embodiment, the vehicle lamp 1 is a tail lamp for a four-wheeled vehicle. However, the vehicle lamp 1 is not limited to this. For example, the vehicle lamp 1 may be a turn lamp, stop lamp, or the like, which are a type of marker lamp, or may be such a lamp for a motorcycle, or may be an interior lamp.

[0066] According to the present invention, a vehicle lamp that can suppress unevenness in appearance while increasing the degree of freedom in arranging light sources is provided, and can be used in fields such as vehicle lamps for automobiles and the like.

Claims

1. A vehicle lamp comprising: a light source; and a plate-shaped light guide having an end face facing the light source and into which light from the light source is incident, and guiding the light incident from the end face to the opposite side to the end face side; wherein the light guide comprises a light entrance portion including the end face and a light exit portion connected to the side opposite the end face side of the light entrance portion; the light entrance portion is provided on at least one main surface of the light entrance portion and has a plurality of light entrance portion steps that internally reflect light incident from the end face; the light exit portion has a shape different from the light entrance portion steps and has a plurality of light exit portion steps that cause light propagating from the light entrance portion to exit from one main surface of the light exit portion; and the amount of light per unit area that exits from the one main surface of the light exit portion is greater than the amount of light per unit area that exits from one main surface of the light entrance portion that faces the one main surface of the light exit portion.

2. The vehicle lamp according to claim 1, wherein the plurality of light entrance step portions are provided on both of the main surfaces of the light entrance portion.

3. The vehicle lamp according to claim 1, wherein the plurality of light entrance steps include a plurality of convex cylindrical steps extending from the end face side toward the light exit side and arranged in parallel to one another.

4. The vehicle lamp according to claim 3, wherein the interval between adjacent light emitting steps is narrower than the interval between adjacent convex cylindrical steps.

5. The vehicle lamp according to claim 3, characterized in that the light source has at least one light-emitting surface from which light is emitted, and the spacing between the convex cylindrical steps is equal to or less than the width of the light-emitting surface in the direction in which the multiple convex cylindrical steps are arranged.

6. A vehicle lamp according to claim 3 or 4, characterized in that the plurality of light entrance steps include concave cylindrical steps located between adjacent convex cylindrical steps and extending from the end face side towards the light exit side.

7. The vehicle lamp according to claim 6, wherein the width of the convex cylindrical step is wider than the width of the concave cylindrical step.

8. The vehicle lamp according to claim 6, wherein the width of the convex cylindrical step is narrower than the width of the concave cylindrical step.

9. The vehicle lamp according to claim 1, wherein the plurality of light entrance steps include a plurality of concave cylindrical steps extending from the end face side toward the light exit side and arranged in parallel with one another.

10. The vehicle lamp according to claim 1, wherein the plurality of light entrance steps include a plurality of convex fisheye steps.

11. The vehicular lamp according to claim 10, wherein the areas between adjacent fish-eye steps on the main surface on which the fish-eye steps of the light entrance portion are provided are recessed.

12. A vehicle lamp according to claim 1, which is a marker lamp.

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