Vehicle lamp

A vehicle lamp includes a light source and a light guide body configured to guide light from the light source therein and emit the light toward a front side of the lamp. The light guide body includes a first rod-shaped light guide portion configured to guide light incident from an incident end surface, a second rod-shaped light guide portion configured to guide the incident light, and a plate-shaped light guide portion formed in an area between the first rod-shaped light guide portion and the second rod-shaped light guide portion. The plate-shaped light guide portion has an end side surface configured to totally reflect at least a portion of light, which travels in the plate-shaped light guide portion, toward the first rod-shaped light guide portion and/or the second rod-shaped light guide portion.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on and claims priority from Japanese Patent Application No. 2016-027654, filed on Feb. 17, 2016, with the Japan Patent Office, the disclosure of which is incorporated herein in its entirety by reference.

TECHNICAL FIELD

The present disclosure relates to a vehicle lamp, and more particularly, to a vehicle lamp using a light guide body.

BACKGROUND

Conventionally, a vehicle lamp in which a plate-shaped light guide plate between two rod-shaped light guide bodies to increase a light-emitting area, thereby improving visibility has been known. For example, Japanese Patent Laid-Open Publication No. 2014-007014 discloses a vehicle lamp that includes a first light guide body extending from a light incident portion so that light from the light-incident portion is guided thereto, a second light guide body extending through a branch portion between the first light guide body and the second light guide body so that light from the light incident portion is guided thereto, and a flat light guide plate formed between the first light guide body and the second light guide body.

SUMMARY

In the vehicle lamp disclosed in Japanese Patent Laid-open Publication No. 2014-007014, although a light-emitting area may be increased, there is a possibility that uniform light emission may not be realized because the light traveling in the flat light guide plate leaks from the end side surfaces of the flat light guide plate, and thus, the light emission intensity of the end side surfaces of the plate-shaped light guide plate is increased.

The present disclosure has been made in consideration of the aforementioned situation, and is to suppress the light emission intensity of the end side surfaces of a plate-shaped light guide portion in a vehicle lamp including a light guide body in which the plate-shaped light guide portion is formed between two rod-shaped light guide portions.

According to an aspect of the present disclosure, a vehicle lamp includes a light source and a light guide body configured to guide light from the light source therein and emit the light toward a front side of the lamp. The light guide body includes a first rod-shaped light guide portion configured to guide light incident from an incident end surface, a second rod-shaped light guide portion configured to guide the incident light, and a plate-shaped light guide portion formed in an area between the first rod-shaped light guide portion and the second rod-shaped light guide portion. The plate-shaped light guide portion has an end side surface configured to totally reflect at least a portion of light, traveling in the plate-shaped light guide portion, toward the first rod-shaped light guide portion and/or the second rod-shaped light guide portion.

The end side surface may be formed as a curved surface that is recessed toward the incident end surface side.

A portion of the first rod-shaped light guide portion near the incident end surface may be curved and may be formed so that a diameter thereof is reduced with decreasing distance to the incident end surface.

The first rod-shaped light guide portion and/or the second rod-shaped light guide portion may be provided with a flat surface formed on a portion of a side surface thereof.

The second rod-shaped light guide portion may be formed to branch from the first rod-shaped light guide portion and extend therefrom.

The second rod-shaped light guide portion may be disposed not to intersect with the first rod-shaped light guide portion.

According to the present disclosure, in a vehicle lamp including a light guide body in which a plate-shaped light guide portion is formed between two rod-shaped light guide portions, the light emission intensity of the end side surface of the plate-shaped light guide portion can be suppressed.

DETAILED DESCRIPTION

Hereinafter, a vehicle lamp according to exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In addition, in the present specification, when terms expressing directions, such as, for example, “up,” “down,” “front,” “rear,” “left,” and “right,” are used, these terms mean the directions in the attitude of the vehicle lamp when the vehicle lamp is mounted on a vehicle.

FIG. 1is a schematic front view for explaining a vehicle lamp10according to an exemplary embodiment of the present disclosure. The vehicle lamp10illustrated inFIG. 1is a rear combination lamp mounted on the rear side of a vehicle.

As illustrated inFIG. 1, the vehicle lamp10includes a lamp body12, and a transparent outer cover14that covers a front opening of the lamp body12. The lamp body12and the outer cover14define a lamp chamber16, and a backup lamp18and a tail lamp20are installed within the lamp chamber16. The backup lamp18and the tail lamp20are fixedly supported by the lamp body12.

As illustrated inFIG. 1, the backup lamp18is disposed in the lower region of the lamp chamber16when viewed from the front side. The structure of the backup lamp18is not particularly limited. For example, a reflector type lamp may be used which reflects light emitted from a light source, such as, for example, a bulb or an LED, using a reflector.

In the vehicle lamp10according to the present exemplary embodiment, the tail lamp20is disposed at the upper side of the backup lamp18. The tail lamp20includes an LED21as a light source, a light guide body23that guides light from the LED21therein to emit the light toward the front side of the lamp, and a red inner lens24that controls the light emitted from the light guide body23. In the present exemplary embodiment, although a red transparent lens, which is colored red and has translucency, is used as the inner lens, a colorless transparent inner lens and a red transparent outer cover (lens) may be used.

FIG. 2is a schematic front view of the tail lamp20.FIG. 3is a schematic rear view of the light guide body23.FIG. 4is a schematic perspective view of the light guide body23.FIG. 5is a cross-sectional view taken along line A-A of the light guide body23illustrated inFIG. 2.FIG. 6is a cross-sectional view taken along line B-B of the light guide body23illustrated inFIG. 2.FIG. 7is a view illustrating the state where light travels inside the light guide body23.

The light guide body23includes a first rod-shaped light guide portion25, a second rod-shaped light guide portion26, and a plate-shaped light guide portion27formed in the area between the first rod-shaped light guide portion25and the second rod-shaped light guide portion26. In the light guide body23, the first rod-shaped light guide portion25, the second rod-shaped light guide portion26, and the plate-shaped light guide portion27are integrally formed. The light guide body23may be formed by extrusion molding a transparent resin, such as, for example, acryl.

The first rod-shaped light guide portion25has an incident end surface28on one end surface thereof, on which the light from the LED21is incident. In the present exemplary embodiment, the incident end surface28is formed to face the rear side of the lamp. The LED21is disposed to face the incident end surface28.

The second rod-shaped light guide portion26is formed to branch from the first rod-shaped light guide portion25near the incident end surface28and linearly extend downward. The first rod-shaped light guide portion25is curved to extend downward after branching from the second rod-shaped light guide portion26.

The first rod-shaped light guide portion25and the second rod-shaped light guide portion26guide the incident light therein to emit the light from respective light-emitting surfaces25aand26aalong the extending direction thereof (the front surface of the side surfaces of the rod-shaped light guide portion) toward the front side of the lamp. Plural steps25cand26care formed on rear surfaces25band26bof the first rod-shaped light guide portion25and the second rod-shaped light guide portion26along the extending direction of the rod-shaped light guide portions to reflect the light traveling in the rod-shaped light guide portions toward the light-emitting surfaces25aand26a. Each of the steps25cand26cmay have a triangular pillar shape.

The plate-shaped light guide portion27extends from the branch portion of the first rod-shaped light guide portion25and the second rod-shaped light guide portion26to the vicinity of the upper edge portion of the backup lamp18(seeFIG. 1) in the area between the first rod-shaped light guide portion25and the second rod-shaped light guide portion26. The plate-shaped light guide portion27is bonded to the side surfaces of the first rod-shaped light guide portion25and the second rod-shaped light guide portion26so as to transmit light. The plate-shaped light guide portion27is formed to be thinner than the first rod-shaped light guide portion25and the second rod-shaped light guide portion26.

As illustrated inFIGS. 3 and 4, plural steps27aare formed on the rear surface of the plate-shaped light guide portion27to reflect the light traveling in the plate-shaped light guide portion27toward the front side of the lamp. The plural steps27amay be configured as, for example, indentations. In addition, the plate-shaped light guide portion27is provided with a fixing hole27b. As illustrated inFIG. 6, a support portion15extending from the lamp body12(see, e.g.,FIG. 1) is inserted into the fixing hole27b, and the light guide body23is fixed with respect to the lamp body12.

The plate-shaped light guide portion27has an end side surface27c, which is close to the upper edge portion of the backup lamp18(see, e.g.,FIG. 1). The end side surface27cis the side surface of the plate-shaped light guide portion27, which is formed between the vicinity of the terminal end of the first rod-shaped light guide portion25and the vicinity of the terminal end of the second rod-shaped light guide portion26. In the present exemplary embodiment, the end side surface27cof the plate-shaped light guide portion27is configured to totally reflect at least a portion of the light traveling in the plate-shaped light guide portion toward the first rod-shaped light guide portion and/or the second rod-shaped light guide portion. Specifically, the end side surface27cis formed as a curved surface, which is recessed toward the incident end surface28side of the light guide body23.

Next, descriptions will be made on how light travels in the light guide body23with reference toFIGS. 5 to 7.

As illustrated inFIG. 5, the light emitted from the LED21is incident into the light guide body23from the incident end surface28. The light is split into the first rod-shaped light guide portion25and the second rod-shaped light guide portion26, and travels in the first and second rod-shaped light guide portions while repeating total reflection. While traveling, the light is reflected at the steps formed on the rear surfaces of the first and second rod-shaped light guide portions to be emitted to the front side of the lamp (see, e.g., light beams L1inFIG. 5).

In addition, a portion of the light traveling in the rod-shaped light guide portions enters the plate-shaped light guide portion27. The light travels in the plate-shaped light guide portion27while repeating total reflection. While traveling, the light is reflected at the steps27aformed in the rear surface of the plate-shaped light guide portion27to be emitted to the front side of the lamp (see, e.g., light beams L2inFIG. 6).

The light traveling in the plate-shaped light guide portion27is not entirely reflected at the steps27ato be emitted to the front side of the lamp, and a portion of the light reaches the end side surface27cof the plate-shaped light guide portion27. As illustrated inFIG. 7, light L3incident on the central portion of the end side surface27cis emitted outward from the end side surface27c. Meanwhile, light L4and L5incident on a position deviated from the central portion of the end side surface27cis totally reflected at the end side surface27cto be directed to the first rod-shaped light guide portion25and the second rod-shaped light guide portion26.

Assuming that the end side surface27cis a flat surface, most of the light reaching the end side surface27cis emitted outward from the end side surface27c. In this case, there is a possibility that the light emission intensity of the end side surface27cis increased, and thus uniform light emission may not be realized. Meanwhile, in the tail lamp20according to the present exemplary embodiment, because a portion of light incident on the end side surface27c(e.g., L4and L5inFIG. 7) is totally reflected at the end side surface27ctoward the first rod-shaped light guide portion25and the second rod-shaped light guide portion26, the amount of light emitted from the end side surface27cis reduced, and thus the light emission intensity of the end side surface27ccan be suppressed. As a result, the uniformity of light emission can be improved.

FIG. 8is an enlarged cross-sectional view of the peripheral portion of the incident end surface28of the light guide body23. As illustrated inFIG. 8, a portion of the first rod-shaped light guide portion25near the incident end surface28is curved toward the rear side of the lamp. When the curved portion is present on the first rod-shaped light guide portion25in this way, there is a possibility that a portion of light incident into the light guide body may not be totally reflected, and thus may leak outward. Therefore, in the present exemplary embodiment, as illustrated inFIG. 8, the portion of the first rod-shaped light guide portion25near the incident end surface28is formed such that the diameter thereof is reduced toward the incident end surface28. More specifically, a portion of the first rod-shaped light guide portion25near the incident end surface28is cut out. InFIG. 8, a cut-out portion80is represented by a dashed line. With the formation of the cut-out portion80, as illustrated by a light beam L6inFIG. 8, a portion of the light incident into the first rod-shaped light guide25from the incident end surface28is totally reflected on the surface81formed by cutting out the portion80, and travels in the first rod-shaped light guide portion25. With the present exemplary embodiment, even when the portion near the incident end surface28is curved, the light incident into the first rod-shaped light guide portion25from the incident end surface28hardly leaks outward, and therefore light utilization efficiency can be improved.

FIG. 9is an enlarged cross-sectional view of the second rod-shaped light guide portion26. As described above, light traveling in the second rod-shaped light guide26is reflected at the steps26cformed on the rear surface26bto be emitted from the light-emitting surface26ato the front side of the lamp (see, e.g., light beams L7).

In the present exemplary embodiment, as illustrated inFIG. 9, a flat surface90is formed on a portion of the side surface of the second rod-shaped light guide portion26. The flat surface90reflects the light from the steps26cto the lateral side of the lamp (see a light beam L8). When the flat surface90is formed on a portion of the side surface of the second rod-shaped light guide portion26in this way, the light may be emitted to the lateral side of the lamp as well as the front side of the lamp, and thus the viewing angle of the lamp may be enlarged.

FIG. 10is an enlarged view of a branch portion of the first rod-shaped light guide portion25and the second rod-shaped light guide portion26. As described above, the first rod-shaped light guide portion25is curved to extend downward after branching from the second rod-shaped light guide portion26. Meanwhile, the second rod-shaped light guide portion26is formed to linearly extend downward after branching from the first rod-shaped light guide portion25. In the case where the second rod-shaped light guide portions25and26branches from each other in this way, when all ends of the second rod-shaped light guide portion26are connected to the first rod-shaped light guide portion25, there is a possibility that most of the light incident into the first rod-shaped light guide portion25from the LED21enters the second rod-shaped light guide portion26and the amount of light entering the first rod-shaped light guide portion25is reduced. Therefore, in the present exemplary embodiment, only a portion26dof the end of the second rod-shaped light guide portion26may be connected to the first rod-shaped light guide portion25, and the remaining portion26emay be in the open state, rather than being connected to the first rod-shaped light guide portion25. With this formation, it is possible to suppress the light incident into the first rod-shaped light guide portion25from the LED21from excessively entering the second rod-shaped light guide portion26. It is also possible to increase the amount of light entering the first rod-shaped light guide portion25.

FIG. 11is a schematic front view for explaining a vehicle lamp according to another exemplary embodiment of the present disclosure. The tail lamp100illustrated inFIG. 11includes a light guide body123. In the same manner as the tail lamp20of the above-described exemplary embodiment, the light guide body123also includes a first rod-shaped light guide portion125, a second rod-shaped light guide portion126, and a plate-shaped light guide portion127formed in the area between the first rod-shaped light guide portion25and the second rod-shaped light guide portion26. The light emitted from a first LED121is incident on the incident end surface of the first rod-shaped light guide portion125, and the light emitted from a second LED122is incident on the incident end surface of the second rod-shaped light guide portion126. The tail lamp100according to the present exemplary embodiment differs from the tail lamp20according to the above-described exemplary embodiment in that the second rod-shaped light guide portion126is disposed not to intersect with the first rod-shaped light guide portion125.

In the same manner as the plate-shaped light guide portion27of the above-described exemplary embodiment, in the plate-shaped light guide portion127of the present exemplary embodiment, an end side surface127cis formed as a curved surface that is recessed toward the incident end surface side. Thus, because a portion of the light incident on the end side surface127cof the plate-shaped light guide portion127is totally reflected at the end side surface127ctoward the first rod-shaped light guide portion125and the second rod-shaped light guide portion126, the amount of light emitted from the end side surface127cis reduced, and thus the light emission intensity of the end side surface127ccan be suppressed. As a result, the uniformity of light emission can be improved.

The present disclosure has been described above based on the exemplary embodiments. It will be understood by a person skilled in the art that the exemplary embodiments are given by way of example, and various modifications can be made by combining respective constituent elements or respective processes, and the modifications fall in the scope of the present disclosure.

For example, although the above-described exemplary embodiments illustrate an LED as a light source, the light source is not limited to the LED, and may be, for example, a semiconductor laser or a bulb.