Light guide, and vehicular lighting tool

Abstract

To provide a light guide and a vehicular lighting tool, capable of improving the luminous efficiency.SOLUTION: A light guide 30 includes light guide units 30R, 30L, the light guide units 30R, 30L each including a body part 31 branching into a first light guide part 40 and a second light guide part 50, and a connecting part 60, the first light guide part 40 having a first curved section 41 curved in the direction separating from the second light guide part 50, and a first emission section 45 connected to the first curved section 41 for emitting light to be transmitted therein, the second light guide part 50 having a second curved section 51 curved in the direction separating from the first light guide part 40, and a second emission section 55 connected to the second curved section 51 for emitting light to be transmitted therein, the connecting part 60 extending from the outer peripheral face of the first curved section 41 to the outer peripheral face of the second curved section 51, where at least part of the light transmitted from the first emission section 45 to the first curved section 41 is transmitted via the connecting part 60 and the second curved section 51 to the second emission section 55.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a light guide and a vehicle lamp. [Background technology]

[0002] 2. Description of the Related Art There are vehicle lamps that include a light source and a light guide that guides light from the light source, and Patent Document 1 below discloses such a vehicle lamp.

[0003] In the vehicle lamp of the following Patent Document 1, the light guide includes a columnar main body portion that guides light incident from one end surface toward the other end side and the other end side is branched into a first light guiding portion and a second light guiding portion, and a columnar joint portion. The branching portion side of the first light guiding portion is a curved portion that curves in a direction away from the second light guiding portion, and the branching portion side of the second light guiding portion is a curved portion that curves in a direction away from the first light guiding portion. The joint portion extends from the outer peripheral surface of the curved portion of the first light guiding portion to the outer peripheral surface of the curved portion of the second light guiding portion. A part of the light incident on the main body portion is guided to the first light guiding portion and exits from a portion on the opposite side of the curved portion to the branching portion side, and another part of the light incident on the main body portion is guided to the second light guiding portion and exits from a portion on the opposite side of the curved portion to the branching portion side. In addition, the connecting portion guides a portion of the light incident from the curved portion in the first light guiding portion to the side opposite the curved portion in the first light guiding portion, and guides a portion of the light incident from the curved portion in the second light guiding portion to the side opposite the curved portion in the second light guiding portion. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2017-147120 A Summary of the Invention [Problem to be solved by the invention]

[0005] In such a light guide, light may be generated in the first light guiding section from the side opposite to the curved section toward the curved section, and light may be generated in the second light guiding section from the side opposite to the curved section toward the curved section. However, Patent Document 1 does not take such light into consideration, and there is a demand for improving efficiency by emitting such light.

[0006] SUMMARY OF THE PRESENT DISCLOSURE An object of the present invention is to provide a light guide and a vehicle lamp that can improve light emitting efficiency. [Means for solving the problem]

[0007] In order to achieve the above object, the light guide of the present invention includes a light guide unit that guides light, the light guide unit including a columnar main body portion that guides light incident from one end face toward the other end side and whose other end side branches into a first light guide section and a second light guide section, and a columnar joint portion, the first light guide section including a first curved section that curves in a direction away from the second light guide section, and a first emission section that is connected to the other end side of the first curved section and emits light propagating inside the first curved section from an outer peripheral surface, The second light-guiding section has a second curved section that curves in a direction away from the first light-guiding section, and a second emission section that is connected to the other end side of the second curved section and emits light propagating inside from its outer peripheral surface, and the connecting section extends from the outer peripheral surface of the first curved section to the outer peripheral surface of the second curved section, and at least a portion of the light propagating from the first emission section to the first curved section propagates to the second emission section via the connecting section and the second curved section.

[0008] In this light guide, a part of the light incident on the main body propagates through the first curved section of the first light guiding section to the first exit section and exits from the first exit section, and another part of the light incident on the main body propagates through the second curved section of the second light guiding section to the second exit section and exits from the second exit section. Also, in this light guide, as described above, at least a part of the light propagating from the first exit section to the first curved section propagates to the second exit section through the joint section and the second curved section. Therefore, according to this light guide, the light propagating to the first curved section in this manner can be emitted from the second exit section of the second light guiding section, and the light emission efficiency can be improved.

[0009] A tangent to a central axis of the first light guiding section at a predetermined point within the first curved section may pass continuously through the connecting portion along the longitudinal direction.

[0010] In the first emission section, the propagating light is emitted from the outer circumferential surface, so the intensity of the light propagating in the longitudinal direction in the first emission section tends to increase toward the central axis of the first light guiding section. Therefore, with this configuration, it is possible to easily propagate high-intensity light from the first emission section to the second emission section via the connecting section and the second curved section.

[0011] At least a portion of the light propagating from the second emission section to the second curved section may propagate to the first emission section via the connecting portion and the first curved section.

[0012] According to such a configuration, light that propagates through the second emission section towards the second curved section and reaches the second curved section can be emitted from the first emission section, thereby making it possible to further improve the light emitting efficiency.

[0013] In this case, a tangent to the central axis of the second light guiding section at a specific point within the second curved section may pass continuously through the connecting portion along the longitudinal direction.

[0014] In the second emission section, similarly to the first emission section, the intensity of light propagating in the longitudinal direction tends to increase toward the central axis of the second light guiding section, and therefore, with this configuration, it is possible to facilitate propagation of high-intensity light from the second emission section to the first emission section via the connecting section and the first curved section.

[0015] The connecting portion may be thinner than the first curved section and the second curved section.

[0016] The outer peripheral surface of the first curved section internally reflects the light incident from one end surface of the main body section and guides it to the first emission section, and the outer peripheral surface of the second curved section internally reflects the light incident from one end surface of the main body section and guides it to the second emission section. Therefore, due to the presence of the joint section, light propagates from the connection section between the first curved section and the joint section and the connection section between the second curved section and the joint section to the joint section. This light is likely to be incident on the outer peripheral surface of the joint section at a small angle of incidence and may leak from the outer peripheral surface. In this light guide, as described above, the joint section is thinner than the first curved section and the second curved section. Therefore, compared to the case where the joint section is thicker than at least one of the first curved section and the second curved section, at least one of the connection section between the first curved section and the joint section and the connection section between the second curved section and the joint section can be made smaller, and the amount of light incident on the outer peripheral surface of the joint section at a small angle of incidence can be reduced. Therefore, according to this light guide, the amount of light leaking from the joint section can be reduced compared to the above case.

[0017] The connecting portion may have a recessed portion on an outer circumferential surface thereof, the recessed portion extending along a longitudinal direction of the connecting portion.

[0018] According to this configuration, it is possible to diffuse light leaking from the outer peripheral surface of the joint portion, and it is possible to prevent the leaking light from appearing as a spot light.

[0019] A minimum value of an angle between an optical axis of light incident from the one end face and a tangent to a central axis of the first light guiding portion within the first curved section may be smaller than 90 degrees.

[0020] The light guide unit may include two light guide units, and one of the end faces of the other end of the first light guide section in one of the light guide units and the end face of the other end of the second light guide section may be connected to the end face of the other end of the first light guide section in the other light guide unit.

[0021] With this configuration, light can be propagated from the first light-guiding section or the second light-guiding section of one light-guide unit to the first light-guiding section of the other light-guide unit, and the light can be propagated to the second light-guiding section of the other light-guide unit and emitted from the second emission section of the second light-guiding section.

[0022] The vehicle lamp of the present invention comprises the above-mentioned light guide, a light source that inputs light to the main body portion from one end face of the main body portion of the light guide, a reflector, and a shielding member, wherein the first emission section and the second emission section emit light from a branching section that branches into the first light guiding section and the second light guiding section in a second direction perpendicular to the first direction toward the connecting section, the reflector reflects the light that is emitted from the light guide in the second direction toward the first direction, and the shielding member covers the first emission section, a portion of the first curved section on the first emission section side of the connection section with the connecting section, the connecting section, a portion of the second curved section on the second emission section side of the connection section with the connecting section, and at least one outer peripheral surface of the second emission section on the first direction side.

[0023] In this vehicle lamp, light is emitted toward the first direction. When the vehicle lamp is viewed from the first direction, the shielding member covers at least one of the first emission section, the portion of the first curved section on the first emission section side from the connection with the connection part, the connection part, the portion of the second curved section on the second emission section side from the connection with the connection part, and the second emission section. Therefore, this vehicle lamp can prevent external light from being guided to an unintended position by the light guide, compared to a case where the shielding member is not provided. Effect of the Invention

[0024] As described above, according to the present invention, it is possible to provide a light guide and a vehicle lamp capable of improving light emitting efficiency. [Brief description of the drawings]

[0025] [Figure 1] 1 is a plan view showing a vehicle lamp according to an embodiment of the present invention; [Diagram 2] 2 is a cross-sectional view of the vehicular lamp taken along line II-II in FIG. 1. [Diagram 3] 13 is an enlarged view of a portion including a branch portion in the right light guide unit. FIG. [Figure 4] 4 is a vertical cross-sectional view of a first emission section along the central axis of the first light guiding section. FIG. [Diagram 5] 11 is a vertical cross-sectional view of a second emission section along the central axis of the second light guiding section. FIG. [Figure 6] FIG. 2 is a cross-sectional view perpendicular to the longitudinal direction of the connecting portion. [Figure 7] 13 is a cross-sectional view of a portion including a joint portion of the right-side light guide unit. FIG. [Figure 8] FIG. 2 is a diagram showing the light guide, the reflector, and the shielding member as viewed from the rear side. [Figure 9] 9 is a cross-sectional view of the vehicular lamp taken along line IX-IX in FIG. 8. [Figure 10] 5 is a diagram similar to FIG. 3 showing a right-side light guide unit and a first light source according to a modified example. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Hereinafter, preferred embodiments of the light guide and vehicle lamp according to the present invention will be described in detail with reference to the drawings. The embodiments exemplified 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 without departing from the spirit of the present invention. In addition, the present invention may be appropriately combined with the components in the embodiments exemplified below. In addition, in the drawings referred to below, the dimensions of each member may be changed in order to facilitate understanding. In addition, in the drawings, for ease of viewing, reference symbols are given to only some of the similar components, and some reference symbols may be omitted.

[0027] Fig. 1 is a plan view showing a vehicle lamp in an embodiment of the present invention. Fig. 2 is a cross-sectional view of the vehicle lamp 1 taken along line II-II in Fig. 1. The vehicle lamp 1 of this embodiment is a tail lamp for a four-wheeled motor vehicle, and is provided at the rear of the vehicle. The upper side in Fig. 1 is the left side of the vehicle, the lower side is the right side of the vehicle, the left side is the rear side of the vehicle, and the right side is the front side 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.

[0028] 1 and 2, the vehicle lamp 1 of this embodiment mainly comprises a housing 10, a light source 20, a light guide 30 that guides light from the light source 20, a reflector 70, and a shielding member 80. Note that in Fig. 1, the housing 10 is shown in horizontal cross section, and in Fig. 2, the housing 10 is omitted.

[0029] The housing 10 has a lamp housing 11 and an optically transparent outer cover 12. The lamp housing 11 has an opening from the rear to the right side, and the outer cover 12 is fixed to the lamp housing 11 so as to close the opening. A light source 20, a light guide 30, a reflector 70, and a shielding member 80 are accommodated in a space R formed by the lamp housing 11 and the outer cover 12.

[0030] The light source 20 of this embodiment includes a first light source 21 and a second light source 22. In this embodiment, the first light source 21 and the second light source 22 have the same configuration, and each includes a light-emitting element 25 that emits red light when the headlights of the vehicle are turned on. The light-emitting element 25 of this embodiment is an LED (Light Emitting Diode), but is not limited thereto.

[0031] The light guide 30 of this embodiment includes a right light guide unit 30R disposed on the right side of the space R, and a left light guide unit 30L disposed on the left side of the space R. The right light guide unit 30R corresponds to a first light source 21, and the left light guide unit 30L corresponds to a second light source 22. In this embodiment, the right light guide unit 30R and the left light guide unit 30L have the same configuration, except that their shapes are generally symmetrical in the left-right direction. Therefore, the right light guide unit 30R will be described below. Note that components of the left light guide unit 30L that are the same as or equivalent to those of the right light guide unit 30R will be denoted by the same reference symbols and will not be described again unless otherwise specified.

[0032] The right light guide unit 30R includes a columnar main body 31 having translucency and a columnar joint 60 having translucency. The main body 31 in this embodiment is a cylindrical member and has a branching portion 35 branching into a first light guide portion 40 and a second light guide portion 50. Therefore, one end side of the main body 31 from the branching portion 35 is made of one columnar member, and the other end side of the main body 31 from the branching portion 35 is made of two columnar members, the first light guide portion 40 and the second light guide portion 50. In this embodiment, the diameters of the first light guide portion 40 and the second light guide portion 50 are approximately constant in the longitudinal direction, and the diameter of the first light guide portion 40 is larger than the diameter of the second light guide portion 50. The diameters of the first light guide portion 40 and the second light guide portion 50 may vary in the longitudinal direction, and the diameter of the first light guide portion 40 may be equal to or smaller than the diameter of the second light guide portion 50.

[0033] FIG. 3 is an enlarged view of a portion including the branching portion 35 in the right light guide unit 30R. The upper side in FIG. 3 is the left side of the vehicle, the lower side is the right side of the vehicle, the left side is the rear side of the vehicle, and the right side is the front side of the vehicle. FIG. 3 illustrates the first light source 21. As shown in FIG. 3, in this embodiment, one end face 32, which is an end face on one end side of the main body 31, faces the left side. The one end face 32 is a flat surface that is approximately perpendicular to the central axis of the main body 31, and the first light source 21 is arranged so that the light emitting element 25 faces the one end face 32 at a predetermined interval. Therefore, in this embodiment, the first light source 21 is arranged inside the one end face 32 in the left-right direction of the vehicle. Light from the first light source 21 enters the main body 31 from the one end face 32, and the main body 31 guides the light entering from the one end face 32 toward the other end side. In this embodiment, the optical axis 21c of the light from the first light source 21 passes through the center of the one end face 32. In addition, a predetermined section 36 extends linearly from the one end face 32 toward the right, and a section 37 between the section 36 and the branching portion 35 is curved toward the rear side.

[0034] In this embodiment, the first light guiding section 40 is located to the left of the second light guiding section 50. The first light guiding section 40 has a first curved section 41 that curves toward the left side, which is a direction away from the second light guiding section 50, and a first emission section 45 that connects to the other end side of the first curved section 41. In this embodiment, the radius of curvature of the first curved section 41 is approximately constant in the longitudinal direction, but is not limited thereto, and may vary, for example, in the longitudinal direction. In addition, in this embodiment, the first curved section 41 connects to the branching section 35. As described above, since the section 37 is curved toward the rear side, the section consisting of the section 37, the branching section 35, and the first curved section 41 in the main body section 31 is curved in an approximately U-shape. Note that the first light guiding section 40 may have a section that extends linearly between the branching section 35 and the first curved section 41, for example.

[0035] The first emission section 45 of the present embodiment extends leftward from the first curved section 41 and is curved so as to be convex toward the rear side.

[0036] Fig. 4 is a vertical cross-sectional view of first emission section 45 along the central axis of first light guiding section 40. As shown in Fig. 4, first emission section 45 of the present embodiment has a reflecting section 46 on the lower side of the outer circumferential surface. This reflecting section 46 is made up of a plurality of steps 47 aligned along the longitudinal direction of first emission section 45. Each step 47 internally reflects light propagating through first emission section 45 and causes it to exit from the upper side of the outer circumferential surface.

[0037] 1, the end face of the other end side of the first emission section 45 opposite to the first curved section 41 side is the left end face of the first emission section 45, and the left end face is the end face of the other end side of the first light guiding section 40. The end face of the other end side of the first emission section 45 opposite to the first curved section 41 side of the left light guide unit 30L is the right end face of the first emission section 45, and the right end face is the end face of the other end side of the first light guiding section 40. The left end face of the first emission section 45, which is the end face of the other end side of the first light guiding section 40 in the right light guide unit 30R, is connected to the right end face of the first emission section 45, which is the end face of the other end side of the first light guiding section 40 in the left light guide unit 30L. In this embodiment, the central axis of the first light guiding section 40 of the right-side light guide unit 30R is connected to the central axis 40c of the first light guiding section 40 of the left-side light guide unit 30L, and the outer peripheral surface of the first light guiding section 40 of the right-side light guide unit 30R and the outer peripheral surface of the first light guiding section 40 of the left-side light guide unit 30L are connected without any step.

[0038] The second light guiding section 50 of the present embodiment has a second curved section 51 that curves toward the right side, which is a direction away from the first light guiding section 40, and a second emission section 55 that connects to the other end side of the second curved section 51. In the present embodiment, the radius of curvature of the second curved section 51 becomes smaller as it moves away from the branching section 35, but is not limited thereto, and may be, for example, approximately constant in the longitudinal direction. In the present embodiment, the second curved section 51 connects to the branching section 35. Note that the second light guiding section 50 may have, for example, a section that extends linearly between the branching section 35 and the second curved section 51. In the present embodiment, the length of the second light guiding section 50 is shorter than the length of the first light guiding section 40, but may be equal to or longer than the length of the first light guiding section 40.

[0039] In this embodiment, the second emission section 55 extends rightward from the second curved section 51 and is curved so as to be convex toward the rear side. The left end face of the second emission section 55 is the end face 53 on the other end side of the second light guiding section 50, and the end face 53 is a hemispherical curved surface. The end face 53 may be a flat surface.

[0040] 5 is a vertical cross-sectional view of the second emission section 55 along the central axis of the second light guiding section 50. As shown in FIG. 5, the second emission section 55 of this embodiment has a reflecting section 56 on the lower side of the outer circumferential surface, similar to the first emission section 45. This reflecting section 56 is made up of a number of steps 57 aligned along the longitudinal direction of the second emission section 55. Each step 57 internally reflects light propagating through the second emission section 55 and causes it to exit from the upper side of the outer circumferential surface.

[0041] 3, the connecting portion 60 of this embodiment is a cylindrical member having translucency, and is located between the first curved section 41 and the second curved section 51, and extends from the outer circumferential surface of the first curved section 41 to the outer circumferential surface of the second curved section 51. The connecting portion 60 of this embodiment extends substantially linearly in the left-right direction, and is located rearward of the branching portion 35. Therefore, the first direction from the branching portion 35 toward the connecting portion 60 is rearward. Furthermore, in this embodiment, the connecting portion 60 is thinner than the first curved section 41 and the second curved section 51.

[0042] FIG. 6 is a cross-sectional view perpendicular to the longitudinal direction of the connecting portion 60. As shown in FIG. 6, the connecting portion 60 has two recessed portions 61 extending along the longitudinal direction of the connecting portion 60 on the upper side of the outer circumferential surface. The cross-sectional shape of each recessed portion 61 is generally arc-shaped. One recessed portion 61 is located forward of the central axis 60c of the connecting portion 60, and the other recessed portion 61 is located rearward of the central axis 60c. The number of recessed portions 61 is not limited, and may be, for example, one or three or more.

[0043] Examples of materials constituting the light guide 30 include transparent resin and glass, and the light guide 30 of this embodiment is made of a colorless and transparent resin. In each of the right light guide unit 30R and the left light guide unit 30L, the branching portion 35 on the one end face 32 side, the branching portion 35, the first light guide portion 40, the second light guide portion 50, and the connecting portion 60 are integral, and there is no gap in the resin between these members. In addition, the right light guide unit 30R and the left light guide unit 30L are also integral, and there is no gap in the resin between the right light guide unit 30R and the left light guide unit 30L.

[0044] FIG. 7 is a cross-sectional view of a portion including the joint 60 of the right light guide unit 30R, and is a cross-sectional view along the central axis of the joint 60. Note that FIG. 7 also illustrates the first light source 21. As shown in FIG. 7, in this embodiment, a tangent 40t to the central axis 40c of the first light guide 40 at a predetermined point 41p in the first curved section 41 on the central axis 40c of the first light guide 40 passes continuously through the joint 60 in the longitudinal direction. Then, the tangent 40t passes through the second curved section 51 and enters the second emission section 55. In addition, the angle θ between the optical axis 21c of the light incident from the one end face 32 and the tangent 40t is smaller than 90 degrees. Therefore, the minimum value of the angle between the optical axis 21c and the tangent in the first curved section 41 of the central axis 40c of the first light guide 40 is smaller than 90 degrees.

[0045] Furthermore, a tangent 50t to the central axis 50c of the second light guiding section 50 at a specific point 51p in the second curved section 51 passes continuously along the longitudinal direction of the connecting section 60. Then, the tangent 50t passes through the first curved section 41 and enters the first emission section 45.

[0046] As shown in FIG. 1 and FIG. 2, the reflector 70 of this embodiment is a plate-like member elongated in the left-right direction. The reflector 70 covers at least the first light guide section 40, the second light guide section 50, and the connecting section 60 of each of the right light guide unit 30R and the left light guide unit 30L of the light guide 30 from the upper side at a predetermined interval. In this embodiment, the reflector 70 covers the first light guide section 40 and the second light guide section 50 from the upper side and the front side. The lower surface of the reflector 70, which is the surface on the light guide 30 side, is a reflective surface 71 that reflects light. A notch 72 is provided in a portion of the front end of the reflector 70 near the branching section 35, and the branching section 35 passes through the notch 72. The front side of the reflector 70 is inclined upward from the front side toward the rear side, and the rear side of the reflector 70 is generally parallel to the horizontal direction. The reflecting surface 71 of the reflector 70 reflects the light emitted from the light guide 30 toward the upper side toward the rear side. As described above, the first direction from the branching portion 35 toward the connecting portion 60 is the rear. Therefore, the upper side is the second direction perpendicular to the first direction. The reflector 70 reflects the light emitted from the light guide 30 toward the upper side, which is the second direction, toward the rear side, which is the first direction, and the shape of the reflecting surface 71 is adjusted to reflect the light in this manner.

[0047] The reflector 70 may be configured, for example, as a metal plate, or as a plate-shaped body made of resin and a light-reflecting film provided on the surface of the body.

[0048] FIG. 8 is a view of the light guide 30, the reflector 70, and the shielding member 80 from the rear side, and is a view of the vicinity of the joint portion 60 of the light guide 30. As shown in FIG. 2 and FIG. 8, the shielding member 80 of this embodiment is a plate-like member that is non-transparent and elongated in the left-right direction. The shielding member 80 of this embodiment has a rear wall 81 extending in the left-right direction and the up-down direction, and a bottom wall 82 extending in the left-right direction and the horizontal direction along the lower end of the rear wall 81. The lower end of the rear wall 81 and the rear end of the bottom wall 82 are connected, and the vertical cross section of the shielding member 80 has a substantially L-shaped shape. The first light guide portion 40 and the second light guide portion 50 in each of the right light guide unit 30R and the left light guide unit 30L of the light guide 30 are disposed on the upper surface of the bottom wall 82, and the front end of the reflector 70 is fixed to the front end of the bottom wall 82. The upper end of the rear wall 81 is located above the first light guiding section 40 and the second light guiding section 50, and below the reflecting surface 71 of the reflector 70. Therefore, the first light guiding section 40 and the second light guiding section 50 are disposed in a space surrounded by the reflector 70 and the shielding member 80, and a gap 85h is formed between the reflector 70 and the shielding member 80. The shielding member 80 covers the first light guiding section 45 of the first light guiding section 40, a portion of the first light guiding section 45 side of the connection portion with the connecting section 60 in the first curved section 41, and the rear side and lower side of each of the outer circumferential surfaces of the connecting section 60. The shielding member 80 covers the portion of the second light guiding section 40 of the second curved section 51 of the first light guiding section 40 on the second light guiding section 55 side of the connection portion with the connecting section 60, and the rear side and lower side of each of the outer circumferential surfaces of the second light guiding section 55. As described above, the first direction from the branching portion 35 toward the connecting portion 60 is the rear, and the upward direction is the second direction perpendicular to the first direction. Therefore, the shielding member 80 of the present embodiment covers the outer circumferential surfaces of the above-mentioned portions of the light guide 30 on the sides opposite to the first direction and the second direction.

[0049] Examples of materials that form the shielding member 80 include metal and resin.

[0050] Next, the operation of the vehicle lamp 1 of this embodiment will be described.

[0051] In this embodiment, when the headlights of the vehicle are turned on, the light emitting elements 25 of the first light source 21 and the second light source 22 each emit red light. The light of the first light source 21 enters the body 31 of the right light guide unit 30R of the light guide 30 from one end surface 32 of the body 31, and the light of the second light source 21 enters the body 31 of the left light guide unit 30L from one end surface 32 of the body 31. Here, the propagation of light in the right light guide unit 30R and the propagation of light in the left light guide unit 30L are substantially the same. For this reason, the following will describe the propagation of light in the right light guide unit 30R, and will omit a description of the propagation of light in the left light guide unit 30L unless otherwise specified.

[0052] As shown in Fig. 7, the light L incident on the main body 31 of the right light guide unit 30R propagates through the main body 31 toward the other end, and a part of the light L propagates from the branching portion 35 to the first light guiding portion 40, and another part of the light L propagates from the branching portion 35 to the second light guiding portion 50. In this embodiment, the amount of light propagating to the first light guiding portion 40 is greater than the amount of light propagating to the second light guiding portion 50. That is, the shape of the branching portion 35 is adjusted so that this occurs. However, the amount of light propagating to the first light guiding portion 40 may be equal to or less than the amount of light propagating to the second light guiding portion 50.

[0053] The light L propagated to the first light guiding section 40 propagates through the first curved section 41 to the first emission section 45, and then propagates through the first emission section 45 toward the other end, that is, the left side. As shown in Fig. 4, this light is internally reflected toward the upward side at the step 47, and is emitted upward from the upper side of the outer circumferential surface. As shown in Fig. 2, the light emitted upward from the first emission section 45 is reflected toward the rear side by the reflecting surface 71 of the reflector 70.

[0054] Moreover, the light propagated from the branching section 35 to the second light guiding section 50 propagates through the second curved section 51 to the second emission section 55, and propagates through the second emission section 55 toward the right side, which is the other end side. As shown in FIG. 5, this light is internally reflected toward the upper side at the step 57, and is emitted from the upper side of the outer circumferential surface toward the upper side. FIG. 9 is a cross-sectional view of the vehicle lamp 1 taken along the line IX-IX in FIG. 8. As shown in FIG. 9, the light emitted upward from the second emission section 55 is reflected toward the rear side by the reflecting surface 71 of the reflector 70. In this embodiment, the end face 53 on the other end side of the second light guiding section 50 is a hemispherical curved surface. Therefore, the light that reaches the end face 53 is internally reflected by the end face 53, and is easily propagated from the second emission section 55 to the second curved section 51. 7, at least a part of the light La propagating from the second emission section 55 to the second curved section 51 propagates to the first emission section 45 via the connecting portion 60 and the first curved section 41. That is, the position and orientation of the connecting portion 60 are adjusted so that the light La propagates in this manner.

[0055] In this embodiment, the left end face of the first emission section 45 of the right light guide unit 30R is connected to the right end face of the first emission section 45 of the left light guide unit 30L. Therefore, light propagating leftward through the first emission section 45 of the right light guide unit 30R enters the first emission section 45 of the left light guide unit 30L and propagates leftward through the first emission section 45 toward the first curved section 41. Light propagating rightward through the first emission section 45 of the left light guide unit 30L enters the first emission section 45 of the right light guide unit 30R and propagates rightward through the first emission section 45 toward the first curved section 41. In this way, at least a part of the light Lb propagating from the first emission section 45 to the first curved section 41 propagates to the second emission section 55 via the joint 60 and the second curved section 51 as shown in FIG. 7. That is, the position and orientation of the joint 60 are adjusted so that the light Lb propagates in this manner. In this embodiment, the reflector 70 covers the joint 60 from above. Then, the light leaking from the upper side of the outer circumferential surface of the joint 60 is reflected toward the rear by the reflecting surface 71 of the reflector 70.

[0056] In this way, the light L incident on the right light guide unit 30R and the left light guide unit 30L in the light guide 30 is emitted upward from the first emission section 45 and the second emission section 55, respectively, and is reflected toward the rear by the reflecting surface 71 of the reflector 70. The light L reflected by the reflector 70 passes through the gap 85h between the reflector 70 and the shielding member 80, and 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 headlights of the vehicle are turned on.

[0057] As described above, the light guide 30 of this embodiment includes the right light guide unit 30R and the left light guide unit 30L. These light guide units 30R and 30L include a main body 31 and a connecting portion 60. The main body 31 guides light incident from one end surface 32 toward the other end side, and the other end side branches into the first light guide section 40 and the second light guide section 50. The first light guide section 40 has a first curved section 41 curved in a direction away from the second light guide section 50, and a first emission section 45 connected to the other end side of the first curved section 41 and emitting light propagating inside from the outer circumferential surface. The second light guide section 50 has a second curved section 51 curved in a direction away from the first light guide section 40, and a second emission section 55 connected to the other end side of the second curved section 51 and emitting light propagating inside from the outer circumferential surface. The connecting portion 60 extends from the outer circumferential surface of the first curved section 41 to the outer circumferential surface of the second curved section 51, and at least a part of the light Lb propagating from the first emission section 45 to the first curved section 41 propagates to the second emission section 55 via the connecting portion 60 and the second curved section 51. Therefore, according to the light guide 30 of this embodiment, the light Lb propagating from the first emission section 45 to the first curved section 41 can be emitted from the second emission section 55 of the second light guiding section 50, and the light emitting efficiency can be improved.

[0058] In the light guide 30 of this embodiment, a tangent 40t of the central axis 40c at a predetermined point 41p in the first curved section 41 on the central axis 40c of the first light guiding section 40 passes continuously through the connecting section 60 in the longitudinal direction. In the first emission section 45, the propagating light is emitted from the outer circumferential surface, so the intensity of the light propagating in the longitudinal direction in the first emission section 45 tends to be higher as it approaches the central axis 40c of the first light guiding section 40. Therefore, according to the light guide 30 of this embodiment, it is possible to easily propagate high-intensity light from the first emission section 45 to the second emission section 55 via the connecting section 60 and the second curved section 51. In addition, even if the connecting section 60 is made thinner than the first curved section 41, it is possible to make it difficult to reduce the amount of light propagating from the first emission section 45 to the second emission section 55. Furthermore, it is sufficient that at least a portion of the light Lb propagating from the first emission section 45 to the first curved section 41 propagates to the second emission section 55 via the connecting portion 60 and the second curved section 51, and the tangent line 40t does not have to pass continuously through the connecting portion 60 along the longitudinal direction.

[0059] In the light guide 30 of this embodiment, at least a part of the light La propagating from the second emission section 55 to the second curved section 51 propagates to the first emission section 45 via the connecting portion 60 and the first curved section 41. Therefore, according to the light guide 30 of this embodiment, the light La propagating from the second emission section 55 to the second curved section 51 can be emitted from the first emission section 45, and the light emitting efficiency can be further improved.

[0060] In the light guide 30 of this embodiment, a tangent 50t to the central axis 50c of the second light guiding section 50 at a specific point 51p in the second curved section 51 on the central axis 50c of the second light guiding section 50 passes continuously through the joint section 60 in the longitudinal direction. In the second emission section 55, similar to the first emission section 45, the intensity of light propagating in the longitudinal direction tends to be higher as it approaches the central axis 50c of the second light guiding section 50. Therefore, according to the light guide 30 of this embodiment, it is possible to easily propagate high-intensity light from the second emission section 55 to the first emission section 45 via the joint section 60 and the first curved section 41. In addition, even if the joint section 60 is made thinner than the second curved section 51, it is possible to make it difficult to reduce the amount of light propagating from the second emission section 55 to the first emission section 45. Furthermore, it is sufficient that at least a portion of the light La propagating from the second emission section 55 to the second curved section 51 propagates to the first emission section 45 via the connecting portion 60 and the first curved section 41, and the tangent line 50t does not have to pass continuously through the connecting portion 60 along the longitudinal direction.

[0061] Here, the outer peripheral surface of the first curved section 41 internally reflects the light L incident from one end face 32 of the main body section 31 and guides it to the first emission section 45, and the outer peripheral surface of the second curved section 51 internally reflects the light L incident from one end face 32 of the main body section 31 and guides it to the second emission section 55. Therefore, due to the presence of the joint section 60, the light L propagates from the connection section between the first curved section 41 and the joint section 60 and the connection section between the second curved section 51 and the joint section 60 to the joint section 60. This light L is likely to be incident on the outer peripheral surface of the joint section 60 at a small angle of incidence, and may leak from the outer peripheral surface. In the light guide 30 of this embodiment, the joint section 60 is thinner than the first curved section 41 and the second curved section 51. Therefore, at least one of the connection between the first curved section 41 and the connecting section 60 and the connection between the second curved section 51 and the connecting section 60 can be made smaller than when the connecting section 60 is thicker than at least one of the first curved section 41 and the second curved section 51, and the amount of light incident on the outer circumferential surface of the connecting section 60 at a small incident angle can be reduced. Therefore, according to the light guide 30 of this embodiment, the amount of light leaking from the connecting section 60 can be reduced compared to the above case. Note that the connecting section 60 may be the same thickness as the first curved section 41 and the second curved section 51, or may be thicker than at least one of the first curved section 41 and the second curved section 51.

[0062] In the light guide 30 of this embodiment, the connecting portion 60 has a recessed portion 61 extending along the longitudinal direction of the connecting portion 60 on the upper side of the outer circumferential surface. According to the light guide 30 of this embodiment, the light leaking from the upper side of the outer circumferential surface of the connecting portion 60 can be diffused, and the leaked light can be prevented from being spot light. The position of the recessed portion 61 is not limited, and may be located, for example, on the front side of the outer circumferential surface. Also, the connecting portion 60 does not have to have the recessed portion 61.

[0063] The light guide 30 of the present embodiment includes two light guide units 30R and 30L, and an end face on the other end side of the first light guide section 40 of the right light guide unit 30R is connected to an end face on the other end side of the first light guide section 40 of the left light guide unit 30L. Therefore, light can be propagated from the first light guide section 40 of the left light guide unit 30L to the first light guide section 40 of the right light guide unit 30R, and the light can be propagated to the second light guide section 50 of the right light guide unit 30R and output from the second output section 55 of the second light guide section 50. The two light guide units 30R and 30L may be separated.

[0064] The vehicle lamp 1 of this embodiment includes the above-mentioned light guide 30, a light source 20, a reflector 70, and a shielding member 80. The light source 20 inputs light L into the main body 31 of the light guide 30 from one end surface 32 of the main body 31. A first direction from the branching portion 35 toward the connecting portion 60 is the rear, and the upper direction is a second direction perpendicular to the first direction. The first emission section 45 and the second emission section 55 emit light upward, which is the second direction side. The reflector 70 reflects the light emitted upward from the light guide 30 to the rear side, which is the first direction side. The shielding member 80 covers the first emission section 45, a portion of the first curved section 41 on the first emission section 45 side from the connection portion with the connecting portion 60, the connecting portion 60, a portion of the second curved section 51 on the second emission section 55 side from the connection portion with the connecting portion 60, and the rear side of the outer circumferential surface of each of the second emission section 55. In the vehicle lamp 1 of this embodiment, light is emitted toward the rear side. Furthermore, when the vehicle lamp 1 is viewed from the rear side, the shielding member 80 covers the first emission section 45, a portion of the first curved section 41 on the first emission section 45 side from the connection portion with the connecting portion 60, the connecting portion 60, a portion of the second curved section 51 on the second emission section 55 side from the connection portion with the connecting portion 60, and the second emission section 55. Therefore, the vehicle lamp 1 of this embodiment can prevent external light from being guided to an unintended position by the light guide 30, compared to a case where the shielding member 80 is not provided. From this viewpoint, the shielding member 80 only needs to cover the first emission section 45, a portion of the first curved section 41 on the first emission section 45 side from the connection portion with the connecting portion 60, the connecting portion 60, the portion of the second curved section 51 on the second emission section 55 side from the connection portion with the connecting portion 60, and at least one rear side of the outer circumferential surface of the second emission section 55.

[0065] Although the present invention has been described above using the above-mentioned embodiments as examples, the present invention is not limited to these.

[0066] For example, in the above embodiment, the light guide 30 including the cylindrical main body 31 has been described as an example. However, the main body 31 only needs to guide the light L incident from one end surface 32 toward the other end side, and the other end side is branched into the first light guiding section 40 and the second light guiding section 50. For example, the main body 31 may be a quadrangular prism. In the above embodiment, the first emission section 45 and the second emission section 55 extend in the left-right direction. However, the extending direction of the first emission section 45 and the second emission section 55 is not limited. In the above embodiment, the part branching from the branching section 35 to the left side is the first light guiding section 40, and the part branching to the right side is the second light guiding section 50, but this is not limited. In the above embodiment, the minimum value of the angle between the optical axis 21c and the tangent to the central axis 40c of the first light guiding section 40 in the first curved section 41 is smaller than 90 degrees. However, this angle may be 90 degrees or more.

[0067] In the above embodiment, the first emission section 45 having the reflecting section 46 made up of a plurality of steps 47 and the second emission section 55 having the reflecting section 56 made up of a plurality of steps 57 have been described as an example. However, the first emission section 45 and the second emission section 55 may have other configurations as long as the light propagating inside is emitted from the outer circumferential surface. For example, the first emission section 45 may not have the reflecting section 46, and the second emission section 55 may not have the reflecting section 56. For example, the first emission section 45 and the second emission section 55 may include a light-transmitting columnar base material made of resin or glass, and an optical element portion that is dispersed in the base material and reflects or refracts light. Examples of the optical element portion that reflects light include inorganic fine particles such as alumina. Examples of the optical element portion that reflects or refracts light include fine particles made of resin or glass having a refractive index different from that of the base material, voids, and the like. According to such a configuration, the light propagating through the base material of the first emission section 45 and the second emission section 55 can be reflected or refracted by the optical element portion and emitted from the outer circumferential surface of the base material.

[0068] In the above embodiment, the first curved section 41 does not have the reflective section 46 consisting of the multiple steps 47, and the second curved section 51 does not have the reflective section 56 consisting of the multiple steps 57. However, the first curved section 41 may have the reflective section 46 and the light may be emitted from the outer circumferential surface of the first curved section 41, or the second curved section 51 may have the reflective section 56 and the light may be emitted from the outer circumferential surface of the second curved section 51.

[0069] In the above embodiment, the vehicle lamp 1 in which the first light source 21 is disposed inside the one end face 32 in the left-right direction of the vehicle has been described as an example. However, the position of the first light source 21 is not limited. Fig. 10 is a diagram similar to Fig. 3 showing a right side light guide unit 30R and the first light source 21 according to a modified example. As shown in Fig. 10, in the modified example, the one end face 32 faces to the right, and the first light source 21 is disposed outside the one end face 32 in the left-right direction of the vehicle.

[0070] In the above embodiment, the light source 20 emitting red light has been described as an example. However, the color of the light emitted by the light source 20 is not limited. For example, the color of the light emitted by the light source 20 may be white. In this case, for example, the light guide 30 is made of red transparent resin or glass.

[0071] In the present embodiment, the end face on the other end side of the first light guiding section 40 in the right light guide unit 30R is connected to the end face on the other end side of the first light guiding section 40 in the left light guide unit 30L. However, it is sufficient that the end face on the other end side of the first light guiding section 40 in one light guide unit and one of the end faces on the other end side of the second light guiding section 50 are connected to the end face on the other end side of the first light guiding section 40 in the other light guide unit. The light guide 30 may be composed of one light guide unit or three or more light guide units. In this case, for example, in adjacent light guide units, the end face of the other end of the first light guide section 40 and the end face of the other end of the second light guide section 50 in one light guide unit that are closer to the other light guide unit may be connected to the end face of the other end of the first light guide section 40 and the end face of the other end of the second light guide section 50 in the other light guide unit that are closer to the one light guide unit.

[0072] In the above embodiment, the vehicle lamp 1 is described as including the light guide 30, the light source 20, the reflector 70, and the shielding member 80. However, the vehicle lamp 1 only needs to include at least the light guide 30 and the light source 20, and may not include, for example, the reflector 70 and the shielding member 80.

[0073] 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, a stop lamp, or the like, or may be one of these lamps for a two-wheeled vehicle. [Industrial Applicability]

[0074] INDUSTRIAL APPLICABILITY According to the present invention, a light guide and a vehicle lamp capable of improving luminous efficiency are provided, and can be used in fields such as vehicle lamps for automobiles and the like. [Explanation of symbols]

[0075] 1. Vehicle lighting fixture 20...Light source 21...1st light source 22...Second light source 30 Light guide 30R Right light guide unit 30L···Left light guide unit 31 Main body 40...1st light guide section 41 First curved section 45 First emission section 50...Second light guide section 51...Second curved section 55...Second exit section 60... Joint 70...Reflector 80... Shielding member

Claims

1. A light guide unit that guides light is provided. The light guide unit includes: a columnar body portion that guides light incident from one end surface toward the other end side, the other end side being branched into a first light guiding portion and a second light guiding portion; A columnar joint and Including, The first light guiding section has a first curved section curved in a direction away from the second light guiding section, and a first emission section connected to the other end side of the first curved section and emitting light propagating inside the first curved section from an outer peripheral surface, The second light guiding section has a second curved section curved in a direction away from the first light guiding section, and a second emission section connected to the other end side of the second curved section and emitting light propagating inside from an outer peripheral surface, The connecting portion extends from an outer circumferential surface of the first curved section to an outer circumferential surface of the second curved section, At least a part of the light propagating from the first emission section to the first curved section propagates to the second emission section via the connecting portion and the second curved section. A light guide characterized by:

2. A tangent to the central axis of the first light guiding section at a predetermined point in the first curved section passes through the connecting portion continuously in the longitudinal direction.

2. The light guide of claim 1.

3. At least a part of the light propagating from the second emission section to the second curved section propagates to the first emission section via the connecting portion and the first curved section.

2. The light guide of claim 1.

4. A tangent to the central axis of the second light guiding section at a specific point within the second curved section passes through the connecting section continuously in the longitudinal direction.

4. The light guide according to claim 3.

5. The connecting portion is thinner than the first curved section and the second curved section.

2. The light guide of claim 1.

6. The connecting portion has a recessed portion extending along the longitudinal direction of the connecting portion on an outer circumferential surface.

2. The light guide of claim 1.

7. The minimum value of the angle between the optical axis of the light incident from the one end face and the tangent to the central axis of the first light guiding portion within the first curved section is smaller than 90 degrees.

2. The light guide of claim 1.

8. The light guide unit includes two of the light guide units, one of the end faces on the other end side of the first light guiding section and the end faces on the other end side of the second light guiding section in one of the light guide units is connected to the end face on the other end side of the first light guiding section in the other light guide unit.

2. The light guide of claim 1.

9. A light guide according to any one of claims 1 to 8; a light source that causes light to be incident on the main body portion from the one end surface of the main body portion of the light guide; A reflector; A shielding member; Equipped with The first emission section and the second emission section emit light in a second direction perpendicular to a first direction from a branching section branched into the first light guiding section and the second light guiding section toward the connecting section, The reflector reflects light emitted from the light guide in the second direction toward the first direction, The shielding member covers the first emission section, a portion of the first curved section on the first emission section side from a connection portion with the connecting portion, the connecting portion, a portion of the second curved section on the second emission section side from a connection portion with the connecting portion, and at least one outer circumferential surface of the second emission section on the first direction side. A vehicle lamp characterized by the above.

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