Vehicle lamp

A vehicle lamp includes a first light guide, a second light guide, a first light source, and a second light source. The first light guide includes a first portion extending in a first direction, a second portion extending in a second direction intersecting the first direction, and a third portion shaped to be bent from the first direction to the second direction and interconnecting the first portion and the second portion. The second light guide extends along the first portion and the third portion and has a shape gradually decreasing in a cross-sectional area outside of the bend of the third portion, thereby merging with the light emitting light guide.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on and claims priority from Japanese Patent Application No. 2018-122651, filed on Jun. 28, 2018, 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 used for a vehicle such as an automobile.

BACKGROUND

In the related art, a vehicle lamp is known, which emits light of a light source toward the front side of the lamp via a light guide. For example, Japanese Patent Laid-Open Publication No. 2012-216279 discloses a structure in which a light source such as an LED is disposed on the end of a rod-shaped light guide and light introduced from the end surface of the light guide is emitted to the front side of a lamp by steps provided on the peripheral surface of the light guide.

SUMMARY

Inventors of the present disclosure have found that there is room for improvement in the utilization efficiency of light in the vehicle lamp of the related art as a result of conducting intensive studies on the vehicle lamp in which light is introduced from the end surface of the rod-shaped light guide and is emitted from the peripheral surface of the light guide.

The present disclosure has been made in consideration of such a circumstance and is to provide a technique that improves the utilization efficiency of light in a vehicle lamp.

In order to achieve the above object, one aspect of the present disclosure is a vehicle lamp. The vehicle lamp includes a first light guide having a rod-shape and configured to emit light, a second light guide having a rod-shape and configured to supply light, a first light source configured to introduce light into the first light guide, and a second light source configured to introduce light into the second light guide. The first light guide includes a first portion extending in a first direction, a second portion extending in a second direction intersecting the first direction, and a third portion shaped to be bent from the first direction to the second direction and interconnecting the first portion and the second portion. The second light guide extends along the first portion and the third portion and has a shape gradually decreasing in a cross-sectional area outside the bend of the third portion, thereby merging with the first light guide. The second light guide introduces the light of the second light source into the first light guide while guiding the light therein. The first light guide emits the light of the first light source and the second light source from the first portion, the third portion, and the second portion while guiding the light therein. According to this aspect, it is possible to improve the utilization efficiency of light in the vehicle lamp.

In the above aspect, the light of the first light source may be introduced into the first light guide from an end surface of the first light guide, and the light of the second light source may be introduced into the second light guide from an end surface of the second light guide. In addition, in any one aspect, the second light guide may have a thickness equal to or less than a thickness of the first light guide.

According to the present disclosure, it is possible to improve the utilization efficiency of light in a vehicle lamp.

DETAILED DESCRIPTION

Hereinafter, the present disclosure will be described based on an exemplary embodiment with reference to the accompanying drawings. The embodiment is not intended to limit the disclosure and is merely given by way of example, and all features or combinations thereof described in the embodiment may not be necessarily essential to the disclosure. The same or equivalent components, members, and processings illustrated in the respective drawings will be designated by the same reference numerals, and a redundant description will be omitted as appropriate. In addition, the scale or shape of each element illustrated in each drawing is set for convenience for ease of description and is not interpreted in a limited manner unless otherwise stated. In addition, when terms such as “first” and “second” are used in the specification or the claims, these terms do not represent any order or importance unless stated otherwise and are used to distinguish any one element from another element. In addition, in each drawing, a part of a member which is not important in describing the embodiment will not be illustrated.

FIG. 1is a front view illustrating a schematic structure of a vehicle lamp according to a first embodiment.FIG. 2is a front view illustrating a schematic structure of a light guide.FIG. 3Ais a perspective view illustrating an end region of the light guide.FIG. 3Bis a perspective view illustrating an end surface of the light guide. The vehicle lamp1according to the present embodiment is, for example, a vehicle headlamp device having a pair of headlamp units disposed on the front left and right sides of a vehicle. Since the pair of headlamp units has an approximately horizontally symmetrical structure and has substantially the same configuration,FIG. 1illustrates a structure of one of the headlamp units as the vehicle lamp1.

The vehicle lamp1includes a lamp body2having an opening on the vehicle front side and a light transmitting outer cover4configured to cover the opening in the lamp body2. A plurality of light sources6and a light guide8are accommodated in a lamp chamber defined by the lamp body2and the outer cover4.

The light sources6are configured with, for example, light emitting diodes (LEDs). In addition, the light sources6may be other semiconductor light emitting elements such as laser diodes (LDs) or organic or inorganic electro luminescence (EL) elements, an incandescent bulb, a halogen lamp, or a discharge bulb. A substrate (not illustrated) on which the light sources6are mounted is fixed to, for example, the lamp body2. The light sources6include a first light source6aand a second light source6b.

The light guide8is a rod-shaped light transmitting member. The light guide8includes a rod-shaped light emitting light guide portion10and a rod-shaped light supplying light guide portion12. The entire light guide8has a schematic shape in which the light guide8extends from the outer side in the vehicle width direction to the inner side in the vehicle width direction at the upper side in the lamp chamber and then turns back to the lower side to be folded to the outer side in the vehicle width direction. The light guide8is fixed to the lamp body2via a support member (not illustrated). For example, the light guide8is formed of a light transmitting resin material such as an acrylic resin or a polycarbonate resin. In the present embodiment, the light emitting light guide portion10and the light supplying light guide portion12are an integrally molded article.

The light emitting light guide portion10includes a first portion14, a second portion16, a third portion18, and a fourth portion20. The first portion14extends in a first direction. In the present embodiment, the first direction is approximately the vehicle width direction. The second portion16extends in a second direction intersecting the first direction. In the present embodiment, the second direction is approximately a direction from the outer side in the vehicle width direction and the upper side in the vertical direction to the inner side in the vehicle width direction and the lower side in the vertical direction. The second portion16is disposed at the inner side in the vehicle width direction and the lower side in the vertical direction of the first portion14.

The third portion18is shaped to be bent from the first direction to the second direction and interconnects the first portion14and the second portion16. An end of the first portion14at the inner side in the vehicle width direction is connected to one end side of the third portion18, and an end of the second portion16at the outer side in the vehicle width direction is connected to the other end side of the third portion18. The third portion18is gently curved or bent so as to be directed to the lower side in the vertical direction with increasing distance from the outer side or decreasing distance to the inner side in the vehicle width direction.

The fourth portion20extends in a third direction intersecting the second direction. In the present embodiment, the third direction is approximately a direction from the inner side in the vehicle width direction and the upper side in the vertical direction to the outer side in the vehicle width direction and the lower side in the vertical direction. The fourth portion20is connected to an end of the second portion16at the inner side in the vehicle width direction, and extends from the aforementioned end to the outer side in the vehicle width direction and to the lower side in the vertical direction. In the present embodiment, the angle formed by the second portion16and the fourth portion20is approximately a right angle or an acute angle.

A region of the peripheral surface of the light emitting light guide portion10that faces the lamp front side configures an emission surface22from which light of the light sources6is emitted. The peripheral surface is a surface that extends along the extension axis (central axis in the extension direction) of a rod-shaped member. That is, the light emitting light guide portion10has the emission surface22shaped in such a manner that the emission surface22extends from the outer side to the inner side in the vehicle width direction and turns back from the inner side in the vehicle width direction to the lower side in the vertical direction to be folded to the outer side in the vehicle width direction. An optical structure23is provided on the peripheral surface of the light emitting light guide portion10that faces the lamp rear side to emit the light in the light emitting light guide portion10from the emission surface22. In the present embodiment, the optical structure23is composed of a plurality of reflective steps. The light emitting light guide portion10emits the light of the light sources6from the emission surface22by the optical structure23while guiding the light therein. The emission surface22is visible as a light emitting portion from the outside of the lamp.

The light supplying light guide portion12extends along the first portion14and the third portion18of the light emitting light guide portion10. The light supplying light guide portion12is in contact with the first portion14and the third portion18of the light emitting light guide portion10at the respective peripheral surfaces thereof. Specifically, the light supplying light guide portion12includes a fifth portion24extending along the first portion14and a sixth portion26extending along the third portion18. The fifth portion24of the present embodiment extends along the first portion14at the upper side in the vertical direction of the first portion14. In addition, the sixth portion26extends along the third portion18at the upper side in the vertical direction of the third portion18. Thus, the sixth portion26extends at the outer side of a curve of the third portion18.

The thickness of the light supplying light guide portion12may be equal to or less than the thickness of the light emitting light guide portion10. For example, the average value of the thickness of the light supplying light guide portion12is equal to or less than the average value of the thicknesses of the first portion14and the second portion16in the light emitting light guide portion10. In other words, the average value of the cross-sectional areas perpendicular to the extension axis of the light supplying light guide portion12is equal to or less than the average value of the cross-sectional areas perpendicular to the extension axes of the first portion14and the second portion16.

The first light source6ais disposed on an end of the light emitting light guide portion10. In the present embodiment, a plurality of first light sources6aare disposed on the end of the light emitting light guide portion10at the outer side in the vehicle width direction. Each first light source6ais disposed such that a light emitting surface thereof faces an end surface28of the light emitting light guide portion10. Thus, light of each first light source6ais introduced into the light emitting light guide portion10from the end surface28of the light emitting light guide portion10. The end surface is a surface that extends in a direction intersecting the extension axis at the end of a rod-shaped member.

The second light source6bis disposed on an end of the light supplying light guide portion12. In the present embodiment, a plurality of second light sources6bare disposed on the end of the light supplying light guide portion12at the outer side in the vehicle width direction. Each second light source6bis disposed such that a light emitting surface thereof faces an end surface30of the light supplying light guide portion12. Thus, light of each second light source6bis introduced into the light supplying light guide portion12from the end surface30of the light supplying light guide portion12.

FIG. 4Ais a vertical cross-sectional view illustrating a schematic structure of a part of the vehicle lamp.FIG. 4Bis a horizontal cross-sectional view illustrating a schematic structure of a part of the light emitting light guide portion. The light guide8is fitted into a holder32and is supported by the lamp body2. The holder32covers the peripheral surface of the light emitting light guide portion10on the lamp rear side. The holder32also functions as a reflector.

In addition, the vehicle lamp1includes an extension member34. The extension member34is disposed so as to surround the light guide8and is fixed to the lamp body2. The extension member34has an opening36which allows the light emitted from the emission surface22to advance toward to the front side of the lamp. An edge38of a part of the opening36is disposed so as to overlap at least a part of the light supplying light guide portion12when viewed from the front side of the lamp. Thus, at least a part of the light supplying light guide portion12may be hidden from the outside of the lamp. As a result, the design and appearance of the vehicle lamp1may be improved.

The light supplying light guide portion12introduces the light of the second light source6binto the light emitting light guide portion10while guiding the light therein. The light of the second light source6bis introduced from the end surface30of the light supplying light guide portion12, repeats internal reflection in the light supplying light guide portion12, and advances to the opposite side end. In this process, the light of the second light source6bis gradually introduced into the light emitting light guide portion10from a region in which the peripheral surface of the light supplying light guide portion12and the peripheral surface of the light emitting light guide portion10are in contact with each other. The light supplying light guide portion12does not have the optical structure23. Thus, substantially all of the light in the light supplying light guide portion12is introduced into the light emitting light guide portion10.

The light emitting light guide portion10emits the light of the first light source6aand the second light source6bfrom the first portion14, the third portion18, and the second portion16while guiding the light therein. The light of the first light source6ais introduced from the end surface28of the light emitting light guide portion10, repeats internal reflection in the light emitting light guide portion10, and advances to the opposite side end. In addition, the light of the second light source6bfrom the light supplying light guide portion12is introduced into the first portion14and the third portion18of the light emitting light guide portion10. The light of the second light source6bintroduced into the light emitting light guide portion10also repeats internal reflection, together with the light of the first light source6a, in the light emitting light guide portion10. The light of the first light source6aand the second light source6badvances to a connection portion of the second portion16and the fourth portion20.

A part of the light of the first light source6aand the second light source6badvancing in the light emitting light guide portion10is reflected by the optical structure23. Thus, the light is emitted from the emission surface22of the first portion14, the third portion18, and the second portion16to the outside of the light emitting light guide portion10. The light emitted from the emission surface22passes through the outer cover4and is irradiated to the front side of the lamp.

The light supplying light guide portion12is not a light guide portion intended for light emission but a light guide portion for supplying light to the light emitting light guide portion10. By supplying the light of the second light source6bfrom the light supplying light guide portion12to the light emitting light guide portion10, the amount of light emitted from the emission surface22may be increased. In addition, the light source6is further disposed on the end of the light emitting light guide portion10opposite to the end surface28. The light emitted from the light source6is mainly emitted from the emission surface22of the fourth portion20.

Subsequently, the shape of a merging portion of the light supplying light guide portion12and the light emitting light guide portion10will be described in detail.FIG. 5is an enlarged front view illustrating a part of the light guide. The light supplying light guide portion12has a shape in which a cross-sectional area D gradually decreases at the outer side of the curve of the third portion18so that the light supplying light guide portion12merges with the light emitting light guide portion10. Specifically, the sixth portion26of the light supplying light guide portion12is shaped such that the cross-sectional area D perpendicular to the extension axis C of the sixth portion26gradually decreases toward the downstream side of light guidance in the light supplying light guide portion12, i.e., with increasing distance from the fifth portion24.

The thickness of the sixth portion26(the distance between one peripheral surface that is in contact with the third portion18and the other peripheral surface that faces away from the one peripheral surface) gradually decreases at the outer side of the curve of the third portion18. In other words, a peripheral surface26aof the sixth portion26opposite to the light emitting light guide portion10approaches the light emitting light guide portion10toward the downstream side of light guidance. Therefore, the peripheral surface26ais a surface that is inclined with respect to the peripheral surface of the third portion18. The direction in which the peripheral surface26ais inclined is the direction toward the third portion18. In addition, the peripheral surface26aof the present embodiment is curved with a curvature larger than that of the third portion18. Thus, the light of the second light source6bentering the sixth portion26from the fifth portion24is reflected by the peripheral surface26atoward the bending direction of the third portion18, i.e., the second direction in which the second portion16extends.

FIG. 6Ais a perspective view illustrating an end region of a light guide according to a reference example.FIG. 6Bis a perspective view illustrating an end surface of the light guide according to the reference example.FIG. 6Cis a schematic view illustrating the advancing direction of light in the light guide according to the reference example. In a structure in which light is introduced from the end surface of a rod-shaped light guide, a desired luminous intensity of light may not be obtained with the number of light sources that may be disposed on the end surface of one light guide.

In order to solve this problem, it is conceivable to devise the shape of the light guide so as to increase the number of light sources that may be provided. The light guide40according to the reference example includes, at the end of a light emitting light guide portion42, a light incident portion44branched from the light emitting light guide portion42. Then, the plurality of first light sources6aare disposed on an end surface46of the light emitting light guide portion42, and the plurality of second light sources6bare disposed on an end surface48of the light incident portion44.

The light emitted from the second light sources6bis introduced into the light incident portion44from the end surface48and is guided by the light incident portion44to be introduced into the light emitting light guide portion42. The light emitted from the first light sources6ais introduced into the light emitting light guide portion42from the end surface46. The light emitting light guide portion42emits the light of the first light sources6aand the second light sources6bfrom an emission surface50while guiding the light therein.

In the light guide40according to the reference example, the amount of light emitted from the emission surface50is increased by introducing the light of the second light source6bfrom the branched light incident portion44to the end of the light emitting light guide portion42. However, in a structure in which the light incident portion44is provided on the end of the light emitting light guide portion42, in many cases, the light incident portion44merges with the light emitting light guide portion42at a straight portion of the light emitting light guide portion42. In this case, as illustrated inFIG. 6C, the light internally reflected from the peripheral surface of the light incident portion44may leak to the outside of the light guide40.

Meanwhile, in the light guide8of the present embodiment, the light supplying light guide portion12merges with the light emitting light guide portion10in the third portion18which is shaped to be bent from the first direction in which the first portion14extends to the second direction in which the second portion16extends. Thus, in the merging portion of the light emitting light guide portion10and the light supplying light guide portion12, the light in the light supplying light guide portion12may be guided to the second portion16. Therefore, in the merging portion, it is possible to prevent the light of the second light source6bfrom leaking to the outside of the light guide8. Thus, most of the light of the second light source6badvancing in the light supplying light guide portion12may be introduced into the light emitting light guide portion10.

The vehicle lamp1may function as a marker lamp such as a turn signal lamp, a daytime running lamp, or a clearance lamp by emitting light from the emission surface22of the light emitting light guide portion10. In addition, the vehicle lamp1may also be used as a headlamp. In addition, the vehicle lamp1may be disposed on the rear of the vehicle and used as, for example, a tail lamp or a brake lamp.

As described above, the vehicle lamp1according to the present embodiment includes the rod-shaped light emitting light guide portion10, the rod-shaped light supplying light guide portion12, the first light source6awhich introduces light into the light emitting light guide portion10, and the second light source6bwhich introduces light into the light supplying light guide portion12. The light emitting light guide portion10includes the first portion14extending in the first direction, the second portion16extending in the second direction intersecting the first direction, and the third portion18shaped to be bent from the first portion14to the second portion16and interconnecting the first portion14and the second portion16. The light supplying light guide portion12extends along the first portion14and the third portion18and has a shape in which the cross-sectional area D gradually decreases at the outer side of the curve of the third portion18so that the light supplying light guide portion12merges with the light emitting light guide portion10. The light supplying light guide portion12introduces the light of the second light source6binto the light emitting light guide portion10while guiding the light therein. The light emitting light guide portion10emits the light of the first light source6aand the second light source6bfrom the first portion14, the third portion18, and the second portion16while guiding the light therein.

Therefore, it is possible to prevent the light in the light supplying light guide portion12from leaking from the light guide8in the merging portion of the light emitting light guide portion10and the light supplying light guide portion12. Therefore, the amount of light emitted from the emission surface22of the light emitting light guide portion10may be increased and the utilization efficiency of light in the vehicle lamp1may be improved. In addition, the appearance of the vehicle lamp1may be improved by preventing the leakage of light.

In addition, in the present embodiment, the light of the first light source6ais introduced into the light emitting light guide portion10from the end surface28of the light emitting light guide portion10. In addition, the light of the second light source6bis introduced into the light supplying light guide portion12from the end surface30of the light supplying light guide portion12. Therefore, the light of the light source6may be introduced without adding the shape of a light incident portion to the light guide8. Therefore, it is possible to prevent the shape of the light guide8from being complicated. In addition, in a structure in which light is introduced from the end surface of a rod-shaped light guide, it is not easy to cause an elongated light emitting surface to emit light uniformly. Meanwhile, in the present embodiment, since light is supplied from the light supplying light guide portion12which extends along the light emitting light guide portion10to the light emitting light guide portion10, the luminous intensity of light may be made uniform.

In addition, in the present embodiment, the thickness of the light supplying light guide portion12is equal to or less than the thickness of the light emitting light guide portion10. Thus, the light supplying light guide portion12may be merged with the light emitting light guide portion10without difficulty. As a result, it is possible to further prevent the leakage of light in the merging portion.

The embodiment of the present disclosure has been described above in detail. The embodiment described above merely shows a specific example for implementation of the present disclosure. The content of the embodiment is not intended to limit the technical scope of the present disclosure, and many design changes such as change, addition, and omission of components are possible without departing from the spirit of the disclosure defined in the claims. In the above-described embodiment, the content in which such design changes are possible is emphasized with a notation such as “of the present embodiment” or “in the present embodiment”, but design changes are also acceptable in the content with no notation. Any combination of the above components is also effective as an aspect of the present disclosure. Hatching applied to the cross section of the drawing does not limit the material of a hatched object.

The light guide8of the embodiment includes the fourth portion20, but the fourth portion20may be omitted. In addition, the arrangement and the number of light sources6are also not limited to those illustrated inFIG. 3B. Arbitrary combinations of the above-described components and conversions of the expression of the present disclosure between a method, an apparatus, and a system, for example, are also effective as aspects of the present disclosure.