Vehicular lamp

A vehicular headlamp (100) including a first lamp unit (10) provided with a first LED (11) and a first translucent member (13) internally reflecting light from the first LED (11) twice and then emitting the reflected light, a second lamp unit (20) provided with a second LED (21) and a second translucent member (23) internally reflecting light from the second LED (21) twice and then emitting the reflected light, and a third lamp unit (30) provided with a third LED (31) and a third translucent member (33) internally reflecting light from the third LED (31) twice and then emitting the reflected light. The first translucent member (13), the second translucent member (23), and the third translucent member (33) are coupled together at their ends in the vehicle width direction.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to vehicular lamps.

2. Description of the Related Art

Conventionally, as described in, e.g., Japanese Patent Application Laid-Open (Kokai) No. 2005-11704, lamp units for vehicular headlamps which include a semiconductor light-emitting element and a translucent member on which light from the semiconductor light-emitting element is incident and from which the light is emitted to the front of the lamp are known. Such lamp units are configured so that the light emitted from the semiconductor light-emitting element is incident to the translucent member, and internally reflected on the front surface of the translucent member, and then internally reflected again on the rear surface thereof and finally emitted out from the front surface. In this case, the central area of the front surface of the translucent member is mirror finished in order to internally reflect the light from the semiconductor light-emitting element. Substantially the entire rear surface of the translucent member is mirror finished in order to reflect again the reflected light from the front surface thereof.

Japanese Patent Application Laid-Open (Kokai) No. 2005-11704 discloses a vehicular headlamp that includes a plurality of such lamp units. In this vehicular headlamp, at least one of the lamp units is configured as a lamp unit that forms a horizontal cut-off line of a low-beam distribution pattern, and at least one of the remainder of the lamp units is configured as a lamp unit that forms an oblique cut-off line of a low-beam distribution pattern.

In recent years, not only high performance but also a non-conventional appearance of sophisticated design have been desired for vehicular lamps.

BRIEF SUMMARY OF THE INVENTION

The present invention was developed in view of the above situations, and it is an object of the present invention to provide a vehicular lamp that has a light source and a translucent member for controlling light from the light source and has an appearance of sophisticated design.

In order to accomplish the above object, a vehicular lamp according to one aspect of the present invention includes:a first lamp unit comprising a first light source and a first translucent member that receives incident light from the first light source and is configured so that the incident light is internally reflected on a front surface of the translucent member and internally reflected on a rear surface of the translucent member and then emitted from the front surface of the translucent member; anda second lamp unit comprising a second light source and a second translucent member that receives incident light from the second light source and is configured so that the incident light is internally reflected on a front surface of the translucent member and internally reflected on a rear surface of the translucent member and then emitted from the front surface of the translucent member; and in this structure,the first translucent member and the second translucent member are coupled together at their ends in a vehicle width direction.

In the above-described vehicular lamp of the present invention, the first translucent member and the second translucent member may be integrally molded by a resin material.

The coupled portion of the first translucent member and the second translucent member can be configured so that light is transmitted from one of the translucent members to the other.

The first light source and the second light source can be supported by a common support member.

The first translucent member and the second translucent member can be configured to form different light distribution patterns.

According to the present invention, as seen from the above, a vehicular lamp that includes a light source and a translucent member for controlling the light from the light source has an appearance of sophisticated design.

DETAILED DESCRIPTION OF THE INVENTION

Hereafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1is a front view showing a vehicular headlamp100according to one embodiment of the present invention.FIG. 2is a horizontal cross-sectional view of the vehicular headlamp100taken along the line2-2inFIG. 1.FIG. 3is a vertical cross-sectional view of the vehicular headlamp100according to the embodiment taken along the line3-3inFIG. 1.

The vehicular headlamp100shown inFIGS. 1 to 3is a headlamp mounted on the left side of the front part of a vehicle. The vehicular headlamp100includes a lamp body104having a recessed portion that opens to the front of the lamp, and a transparent cover102covering the opening of the lamp body104. The lamp body104and the cover102form a lamp chamber106.

Three lamp units are provided in the lamp chamber106. A first lamp unit10is provided nearest to the vehicle center in the vehicle width direction, a second lamp unit20is provided next to the first lamp unit10, and a third lamp unit30is provided farthest from the vehicle center in the vehicle width direction, the second lamp unit20thus being provided in the middle or between the first and third lamp units10and30. In the vehicular headlamp100according to this embodiment, the first lamp unit10, the second lamp unit20, and the third lamp unit30are formed integrally. The first lamp unit10, the second lamp unit20, and the third lamp unit30are attached to the lamp body104via a first aiming screw108and a second aiming screw110.

FIG. 4is a diagram of a light distribution pattern that is formed by the vehicular headlamp100of the shown embodiment.FIG. 4transparently shows a low-beam distribution pattern LP that is formed by the light radiated forward from the vehicular headlamp100on an imaginary vertical screen positioned 25 m ahead of the lamp.

As shown inFIG. 4, the low-beam distribution pattern LP has at its upper end a horizontal cut-off line CL1that extends in the horizontal direction and an oblique cut-off line CL2that extends in the upper left direction at a predetermined angle (e.g.,15°) from the horizontal cut-off line CL1. In the low-beam distribution pattern LP, an elbow point E that is an intersection of the horizontal cut-off line CL1and the oblique cut-off line CL2is located about 0.5° to 0.6° below a point H-V so as to be a vanishing point in the forward direction of the lamp.

The low-beam distribution pattern LP is formed as a combined light distribution pattern of a horizontal/oblique cut-off line forming pattern P1(solid line), a first diffusion region forming pattern P2(broken line), and a second diffusion region forming pattern P3(chain line).

The horizontal/oblique cut-off line forming pattern P1is a light distribution pattern that forms the horizontal cut-off line CL1and the oblique cut-off line CL2. The horizontal/oblique cut-off line forming pattern P1is formed by light radiation from the first lamp unit10. The first diffusion region forming pattern P2is a light distribution pattern forming a diffusion region of the low-beam distribution pattern LP and supplementarily forming the horizontal cut-off line CL1. The first diffusion region forming pattern P2is formed by light radiation from the second lamp unit20. The second diffusion region forming pattern P3is a light distribution pattern having a wider radiation range in the horizontal direction than that of the first diffusion region forming pattern P2and supplementarily forming the distribution region of the low-beam distribution pattern LP. The second diffusion region forming pattern P3is formed by light radiation from the third lamp unit30. The first lamp unit10, the second lamp unit20, and the third lamp unit30are thus configured to form different light distribution patterns.

A light distribution pattern to be formed can be selected according to, e.g., a driver's command. For example, only the first lamp unit10and the second lamp unit20can be lit to form a combined light distribution pattern of the horizontal/oblique cut-off line forming pattern P1and the first diffusion region forming pattern P2.

Referring back toFIGS. 1 to 3, the structures of the first lamp unit10, the second lamp unit20, and the third lamp unit30will be described.

The first lamp unit10has a rectangular first LED11, a first substrate12, a first translucent member13, and a first heat sink14. The first LED11is provided on the first substrate12, and it emits light by power supplied from the first substrate12. The first substrate12is mounted on the first base portion14aof the first heat sink14. A plurality of heat radiation fins14bare formed on the first base portion14aof the first heat sink14to radiate heat generated by light emission of the first LED11.

Light emitted from the first LED11is incident on the first translucent member13located in front of the first LED11. The incident light is internally reflected on the front surface13aof the first translucent member13and internally reflected again on the rear surface13bof the first translucent member13and then emitted from the front surface13aof the first translucent member13. In other words, the light incident on the first translucent member13is internally reflected twice in the first translucent member13, and then emitted from the first translucent member13.

The first translucent member13is a molded member of a transparent synthetic resin such as acrylic resin. The front surface13aof the first translucent member13is a gently curved, generally flat surface, and its rear surface13bis generally formed in the shape of a paraboloid of revolution. A front reflecting portion15internally reflecting light emitted from the first LED11to the rear surface13bis formed on the front surface13aof the first translucent member13. The front reflecting portion15is a circular area centered on the optical axis of the first lamp unit10, and is mirror finished by aluminization, etc. The outer peripheral edge of the front reflecting portion15is positioned such that the incident angle of the light from the first LED11incident on the front surface13aof the first translucent member13is substantially equal to the critical angle of the first translucent member13. Thus, the light emitted from the first LED11is internally reflected by the mirror-finished front reflecting portion15and is totally internally reflected on the outer peripheral side that is not covered by the front reflecting portion15.

An accommodating space16surrounding the first LED11is formed on the rear side of the first translucent member13. This accommodating space16is formed in the shape of a hemispherical surface centered on the center of light emission of the first LED11, and it functions as an incident portion that directs the light from the first LED11into the first translucent member13. The accommodating space16can be filled with a transparent resin such as epoxy resin. In this case, the light emitted from the first LED11can be directed into the first translucent member13without being refracted on the hemispherical surface.

A rear reflecting portion17that reflects the reflected light from the front reflecting portion15as light emitted to the front of the vehicle is formed on the rear surface13bof the first translucent member13. For this rear reflecting portion17, the entire rear surface13bexcept the recessed portion having the shape of the hemispherical surface and forming the accommodating space16is mirror finished by aluminization, etc.

In the shown embodiment, the first LED11of the first lamp unit10is provided such that its long side is inclined with respect to the horizontal direction. The inclination angle of the first LED11with respect to the horizontal direction can be substantially equal to that of the oblique cut-off line CL2. The rear reflecting portion17formed on the rear surface13bof the first translucent member13is divided into an oblique cut-off line forming region that forms the horizontal cut-off line CL1and an oblique line forming region that forms the oblique cut-off line CL2. The horizontal/oblique cut-off line forming pattern P1as shown inFIG. 4can thus be formed by the single first lamp unit10. Such a first lamp unit10is disclosed in detail in Japanese Patent Application Laid-Open (Kokai) No. 2011-100692 filed by the applicant of the present application.

The second lamp unit20will be described below. The second lamp unit20is provided so as to adjoin the first lamp unit10, and is configured to form the first diffusion region forming pattern P2shown inFIG. 4.

The second lamp unit20has a structure similar to the first lamp unit10, and it includes a rectangular second LED21, a second substrate22, a second translucent member23, and a second heat sink24. The second LED21is provided on the second substrate22, and emits light by power supplied from the second substrate22. The second substrate22is mounted on a second base portion24aof the second heat sink24. A plurality of heat radiation fins24bare formed on the second base portion24aof the second heat sink24to radiate heat generated by light emission of the second LED21.

Light emitted from the second LED21is incident on the second translucent member23located in front of the second LED21. The incident light is internally reflected on the front surface23aof the second translucent member23and internally reflected again on the rear surface23bof the second translucent member23and then emitted from the front surface23aof the second translucent member23.

The second translucent member23has a different shape from the first translucent member13, but it basically has a structure similar to the first translucent member13. More specifically, the front surface23aof the second translucent member23is a gently curved, generally flat surface, and its rear surface23bis generally formed in the shape of a paraboloid of revolution. A circular front reflecting portion25internally reflecting the light emitted from the second LED21to the rear surface23bis formed on the front surface23aof the second translucent member23by, e.g., aluminization etc. The light emitted from the second LED21is internally reflected by the mirror-finished front reflecting portion25and is totally internally reflected on the outer peripheral side that is not covered by the front reflecting portion25.

An accommodating space26surrounding the second LED21is formed on the rear side of the second translucent member23. The accommodating space26can be filled with a transparent resin such as epoxy resin.

A rear reflecting portion27that reflects the reflected light from the front reflecting portion25as light emitted to the front of the vehicle is formed on the rear surface23bof the second translucent member23by aluminization, etc.

In the shown embodiment, the second LED21of the second lamp unit20is provided such that its long side is parallel to the horizontal direction. The shape of the rear reflecting portion27formed on the rear surface23bof the second translucent member23is designed such that the horizontal diffusion angle of the emitted light from the front surface23aof the second translucent member23is larger than that of the first translucent member13. The first diffusion region forming pattern P2as shown inFIG. 4can thus be formed.

The third lamp unit30will be described below. The third lamp unit30is provided so as to adjoin the second lamp unit20, and it is configured to form the second diffusion region forming pattern P3shown inFIG. 4.

The third lamp unit30has a structure similar to the first lamp unit10and the second lamp unit20, and it includes a rectangular third LED31, a third substrate32, a third translucent member33, and a third heat sink34. The third LED31is provided on the third substrate32and emits light by power supplied from the third substrate32. The third substrate32is mounted on a third base portion34aof the third heat sink34. A plurality of heat radiation fins34bare formed on the third base portion34aof the third heat sink34to radiate heat generated by light emission of the third LED31.

Light emitted from the third LED31is incident on the third translucent member33located in front of the third LED31. The incident light is internally reflected on the front surface33aof the third translucent member33and internally reflected again on the rear surface33bof the third translucent member33and then emitted from the front surface33aof the third translucent member33.

The third translucent member33has a different shape from the first translucent member13, but it basically has a structure similar to the first translucent member13and the second translucent member23. In other words, the front surface33aof the third translucent member33is a gently curved, generally flat surface, and its rear surface33bis generally formed in the shape of a paraboloid of revolution. A circular front reflecting portion35internally reflecting the light emitted from the third LED31to the rear surface33bis formed on the front surface33aof the third translucent member33by, e.g., aluminization etc. The light emitted from the third LED31is internally reflected by the mirror-finished front reflecting portion35and is totally internally reflected on the outer peripheral side that is not covered by the front reflecting portion35.

An accommodating space36surrounding the third LED31is formed on the rear side of the third translucent member33. The accommodating space36can be filled with a transparent resin such as epoxy resin.

A rear reflecting portion37that reflects the reflected light from the front reflecting portion35as light emitted to the front of the vehicle is formed on the rear surface33bof the third translucent member33by aluminization etc.

In the shown embodiment, the third LED31of the third lamp unit30is provided such that its long side is parallel to the horizontal direction. The shape of the rear reflecting portion37formed on the rear surface33bof the third translucent member33is designed such that the horizontal diffusion angle of the emitted light from the front surface33aof the third translucent member33is larger than that of the second translucent member23. The second diffusion region forming pattern P3as shown inFIG. 4can thus be formed.

In the vehicular headlamp100according to the shown embodiment, the translucent member of each lamp unit is coupled to the translucent member of the adjoining lamp unit at their ends in the vehicle width direction. More specifically, as shown inFIG. 2, the outer end, in the vehicle width direction, of the first translucent member13is coupled to the inner end, in the vehicle width direction, of the adjoining second translucent member23. The portion where the first translucent member13and the second translucent member23are coupled together is referred to as a “first coupled portion41.” The outer end of the second translucent member23, in the vehicle width direction, is coupled to the inner end, in the vehicle width direction, of the adjoining third translucent member33. The portion where the second translucent member23and the third translucent member33are coupled together is referred to as a “second coupled portion42.”

The first translucent member13, the second translucent member23, and the third translucent member33are integrally molded by a transparent resin material such as acrylic resin. The front surface13aof the first translucent member13, the front surface23aof the second translucent member23, and the front surface33aof the third translucent member33are formed in the shape of a gently curved, continuous single flat surface as shown inFIGS. 1and2. Integrally molding the first translucent member13, the second translucent member23, and the third translucent member33can implement a lamp unit having an integral appearance of sophisticated design. Moreover, integrally molding the three translucent members reduces the number of parts, which is advantageous in terms of cost.

As shown inFIG. 2, the first coupled portion41and the second coupled portion42are thinner than the remaining portion of the translucent members. The thickness of the first coupled portion41and/or the second coupled portion42may be set so that light can be transmitted from one of the coupled translucent members to the other. For example, light from the first LED11of the first lamp unit10can be transmitted through the first coupled portion41and the second coupled portion42, and light from the second LED21of the second lamp unit20can be transmitted through the first coupled portion41and the second coupled portion42. However, the light distribution pattern that is supposed to be formed by each lamp unit can be changed as the amount of light that is transmitted through the coupled portion increases. Accordingly, the thickness of the first coupled portion41and the second coupled portion42is set to an appropriate value so as not to affect the light distribution patterns.

In the case where the coupled portions are formed so that light can be transmitted therethrough, light from the first LED11and the second LED21is transmitted through the second coupled portion42into the third translucent member33when, e.g., only the first lamp unit10and the second lamp unit20are lit. This can give such an appearance as if the third lamp unit30emitted light and the light-emitting area were expanded.

In the shown embodiment, the first heat sink14, the second heat sink24, and the third heat sink34are formed integrally. More specifically, the outer end, in the vehicle width direction, of the first base portion14aof the first heat sink14is coupled to the inner end, in the vehicle width direction, of the second base portion24aof the adjoining second heat sink. The outer end, in the vehicle width direction, of the second base portion24aof the second heat sink24is coupled to the inner end, in the vehicle width direction, of the third base portion34aof the adjoining third heat sink34. The first LED11, the second LED21, and the third LED31are thus supported by an integral common support member (heat sink). This integral heat sink also supports the first translucent member13, the second translucent member23, and the third translucent member33that are formed integrally.

A first aiming screw attaching portion50to which the first aiming screw108is attached is formed in the inner end, in the vehicle width direction, of the first base portion14aof the first heat sink14, and a second aiming screw attaching portion51to which the second aiming screw110is attached is formed in the outer end, in the vehicle width direction, of the third base portion34aof the third heat sink34. The attitude of the first lamp unit10, the second lamp unit20, and the third lamp unit30can be integrally changed by rotating the first aiming screw108and the second aiming screw110, so that aiming of the first lamp unit10, the second lamp unit20, and the third lamp unit30can be collectively performed when, e.g., the vehicle is shipped or inspected.

Although the first translucent member13, the second translucent member23, and the third translucent member33are integrally molded in the above embodiment, the translucent members can be formed as separate members and provided so as to be coupled together at their ends in the vehicle width direction. In this case, the interface of the coupled portions may be subjected to such a treatment as formation of an antireflection film so that light incident on the interface does not reflect in unintended directions.

FIG. 5is a diagram illustrating another light distribution pattern formed by the vehicular headlamp100according to the embodiment. The light distribution pattern shown inFIG. 5is different from that shown inFIG. 4in that the light distribution pattern ofFIG. 5has a high-beam forming pattern P4instead of the second diffusion region forming pattern P3. The high-beam forming pattern P4is formed by light radiation from the third lamp unit30. The high-beam forming pattern P4as shown inFIG. 5can be formed by changing the direction of the optical axis of the third lamp unit30and the shape of the rear reflecting portion37.

When a low-beam distribution pattern is formed by the vehicular headlamp100capable of forming the light distribution pattern shown inFIG. 5, the first lamp unit10and the second lamp unit20are lit, and the third lamp unit30is unlit to form a combined light distribution pattern of the horizontal/oblique cut-off line forming pattern P1and the first diffusion region forming pattern P2. On the other hand, when forming a high-beam distribution pattern, all of the first lamp unit10, the second lamp unit20, and the third lamp unit30are lit to form a combined light distribution pattern of the horizontal/oblique cut-off line forming pattern P1, the first diffusion region forming pattern P2, and the second diffusion region forming pattern P3. Thus, the light distribution pattern that is formed by the vehicular headlamp100according to the shown embodiment is not particularly limited, and various light distribution patterns can be formed.

FIG. 6is a horizontal cross-sectional view showing a vehicular headlamp600according to another embodiment of the present invention. Since the configuration of the second lamp unit20and the third lamp unit30of the vehicular headlamp600shown inFIG. 6is similar to that in the vehicular headlamp100shown inFIG. 2etc., detailed description thereof will be omitted.

In the vehicular headlamp600of the embodiment ofFIG. 6, a first lamp unit610that forms the horizontal/oblique cut-off line forming pattern P1is different in configuration from the first lamp unit10shown inFIG. 2etc. The first lamp unit610is a so-called projector-type lamp unit, and it includes a first LED611that emits light upward, a reflector618that reflects the light from the first LED611, a shade (not shown since it is hidden from view by the reflector618) that blocks part of the reflected light from the reflector618to form the horizontal cut-off line CL1and the oblique cut-off line CL2, and a projection lens613that projects the light having passed through the shade to the front of the lamp. The first LED611and the reflector618are supported by a first heat sink614.

In the embodiment ofFIG. 6, the projection lens613of the first lamp unit610is molded by a transparent resin material such as acrylic resin integrally with the second translucent member23of the second lamp unit20and the third translucent member33of the third lamp unit30. In other words, the outer end, in the vehicle width direction, of the projection lens613in the vehicle width direction is coupled to the inner end, in the vehicle width direction, of the second translucent member23via a first coupled portion641. The thickness of the first coupled portion641can be set so that the light can be transmitted from the first lamp unit610to the second lamp unit20.

As in the embodiment ofFIG. 6, integrally molding the projection lens613, the second translucent member23, and the third translucent member33can implement a lamp unit having an integral appearance of sophisticated design. Moreover, the number of parts is reduced, which is advantageous in terms of the manufacturing cost.

The present invention is described above based on the embodiments. It should be understood by those skilled in the art that these embodiments are by way of example only, and various modifications can be made to the combination of the components and the treatment processes and such modifications are within the scope of the present invention.