Vehicle lamp

There is provided a vehicle lamp including: a light source; a lens disposed on a front side of the light source and having a front surface and a rear surface which is opposite to the front surface and faces the light source, wherein the lens has a convex lens shape, and a curvature of the rear surface is larger than that of the front surface; and a reflector disposed on a rear side of the lens and configured to reflect direct light emitted from the light source toward the lens. The vehicle lamp is configured to form a light distribution pattern by controlling a deflection of the direct light using the lens.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from Japanese Patent Application No. 2013-213872, filed on Oct. 11, 2013, the entire contents of which are hereby incorporated by reference.

BACKGROUND

1. Technical Field

The present disclosure relates to a vehicle lamp which is configured to form a light distribution pattern by subjecting direct light emitted from a light source to deflection control using a lens disposed on the front side thereof.

2. Description of the Related Art

For example, as disclosed in JP-A-2013-26185, there is known a so-called direct projection-type vehicle lamp which is configured to form a light distribution pattern by subjecting the light emitted from a light source to deflection control using a lens disposed on the front side thereof.

In the direct projection-type vehicle lamp, there is a problem that it is not easy to increase the utilization efficiency of the light emitted from the light source and therefore it is not possible to sufficiently secure the brightness of a light distribution pattern.

On the contrary, by adopting a configuration in which a reflector for reflecting the direct light from the light source toward the lens is disposed on the rear side of the lens, it is possible to improve the utilization efficiency of the light emitted from the light source by the amount of light reflected by the reflector.

However, generally, a lens used in the direct projection-type vehicle lamp has a convex lens shape where the curvature of the front surface is larger than that of the rear surface. Accordingly, in case of adding the reflector simply, there exists a problem in that a portion of the light that is reflected by the reflector and incident on the lens is totally reflected at the front surface of the lens. As a result, there is a problem in that it is not possible to sufficiently increase the light emission efficiency from the lens and thus it is difficult to secure a sufficient brightness of the light distribution pattern.

SUMMARY OF THE INVENTION

The present invention is directed toward a vehicle lamp which is configured to form a light distribution pattern by subjecting direct light emitted from a light source to deflection control using a lens disposed on the front side of the light source and which is capable of sufficiently securing the brightness of a light distribution pattern using a reflector.

According to one or more aspects of the present invention, there is provided a vehicle lamp comprising: a light source; a lens disposed on a front side of the light source and having a front surface and a rear surface which is opposite to the front surface and faces the light source, wherein the lens has a convex lens shape, and a curvature of the rear surface is larger than that of the front surface; and a reflector disposed on a rear side of the lens and configured to reflect direct light emitted from the light source toward the lens. The vehicle lamp is configured to form a light distribution pattern by controlling a deflection of the direct light using the lens.

The type of the “light source” is not particularly limited. For example, a light emitting element such as a light emitting diode and a laser diode, or a light source bulb or the like can be employed as the light source.

A specific curvature size of each of the front surface and the rear surface in the “lens” is not particularly limited, as long as the lens has a convex lens shape where the curvature of the rear surface is larger than that of the front surface.

The type of the “light distribution pattern” is not particularly limited. For example, a low-beam light distribution pattern, a high-beam light distribution pattern, a fog-lamp light distribution pattern or the like can be employed.

A specific arrangement and light reflecting structure and the like of the “reflector” is not particularly limited, as long as the reflector is configured to reflect the direct light from the light source toward the lens.

As illustrated in the above configuration, the vehicle lamp according to the present invention is configured to form a light distribution pattern by controlling the deflection of the direct light from the light source using the lens disposed on the front side thereof. However, since the reflector for reflecting the direct light from the light source toward the lens is disposed on the rear side of the lens, it is possible to improve the utilization efficiency of the light emitted from the light source by the amount of light reflected by the reflector.

At that time, since the lens has a convex lens shape where the curvature of the rear surface is larger than that of the front surface, it is possible to cause the light reflected by the reflector to be gradually refracted on the front surface and the rear surface of the lens. Therefore, in the light that is reflected by the reflector and incident on the lens, the percentage of the light that is totally reflected on the front surface of the lens can be reduced to zero or the percentage can be significantly reduced as compared to the prior art configuration. Thus, it is possible to sufficiently improve the light emission efficiency from the lens.

Accordingly, it is possible to sufficiently secure the brightness of the light distribution pattern using the reflector.

According to the present invention as described above, in the vehicle lamp configured to form a light distribution pattern by controlling the deflection of the direct light emitted from the light source using the lens disposed on the front side thereof, it is possible to sufficiently secure the brightness of the light distribution pattern using the reflector.

Furthermore, when the curvature of the rear surface of the lens is larger than that of the front surface, as described in the present invention, it is possible to easily secure a space for placing the reflector. Thereby, it is possible to prevent, in advance, the size of the lamp unit from being increased due to the addition of the reflector.

In the above configuration, by adopting a configuration that the reflector has a multistage reflective surface, it is possible to finely control the size and forming position of a light distribution pattern which is formed by the light reflected by the reflector. Thereby, it is possible to reduce the light unevenness of the whole light distribution pattern.

In the above configuration, by adopting a configuration that a portion of the rear surface of the lens, which faces the reflector, has a linear cross-sectional shape, it can be easily prevented that the light reflected by the reflector is largely refracted on the rear surface of the lens and totally reflected on the front surface of the lens.

In the above configuration, by adopting a configuration that a panel member is disposed around the lens, it is possible to improve the design of the lamp.

At that time, the panel member may be formed with a wall surface portion extending forward from near an outer peripheral edge of the lens. In this case, at least a portion of the reflector is disposed on one side with respect to an axis while the wall surface portion is disposed on the other side with respect to the axis, wherein the axis extends in a forward and rearward direction so as to pass through the light source. With these configurations, the following operational effects can be obtained.

Namely, when a portion of the light emitted from the lens is shielded by the wall surface portion of the panel member, the brightness of the end portion of the light distribution pattern on the side where the wall surface portion is disposed is lowered. On the contrary, when the light reflected by the reflector and passing through the lens is directed toward the wall surface portion side through the axis, the reflector can provide the brightness corresponding to the amount of light shielded by the wall surface portion of the panel member. Accordingly, it is possible to prevent, in advance, the brightness of the end portion of the light distribution pattern on the side where the wall surface portion is disposed from being lowered. As a result, it is possible to form the light distribution pattern with a desired brightness.

In the above configuration, by adopting a configuration that the reflector is disposed around the light source, and the direct light reflected by the reflector is directed toward an axis, wherein the axis extends in a forward and rearward direction so as to pass through the light source, it is possible to prevent, in advance, the brightness of the end portion of the light distribution pattern on the side where the wall surface portion is disposed from being inadvertently lowered due to a structure around the lens.

DETAILED DESCRIPTION

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Moreover, in each drawing used in descriptions below, scales are appropriately modified to show each member at a recognizable size.

FIG. 1is a plan sectional view showing a vehicle lamp10according to an illustrative embodiment of the present invention.

As shown inFIG. 1, the vehicle lamp10is a headlamp provided on the right front end of a vehicle and has a configuration that two lamp units20A,20B are accommodated in a lamp chamber formed by a lamp body12and a translucent cover14.

The translucent cover14is formed to extend to the rear from the inside in a vehicle width direction while extending in a lamp forward and rearward direction. In the lamp chamber, a panel member16is disposed along the translucent cover14. At positions of the panel member16corresponding to respective lamp units20A,20B, openings16a,16bare respectively formed so as to surround each of the lamp units.

Two lamp units20A,20B are arranged in such a way that the lamp unit20A located on the outside in the vehicle width direction is displaced to the rear side of the lamp unit20B located on the inside in the vehicle width direction.

These two lamp units20A,20B have the same configurations. Accordingly, a configuration of the lamp unit20A located on the outside in the vehicle width direction will be explained in the following description.

FIG. 2is a detailed view of a region II of the vehicle lamp10shown inFIG. 1. Further,FIG. 3is a sectional view of the vehicle lamp10shown inFIG. 2, which is taken along a line III-III inFIG. 2.FIG. 4is a front view of the vehicle lamp10shown inFIG. 2, which is seen from a direction indicated by an arrow IV inFIG. 2.

As shown in these figures, the lamp unit20A includes a light source22, a lens24disposed on the front side of the light source22and a pair of left and right reflectors26L,26R. The lamp unit20A is configured to form a high-beam light distribution pattern by subjecting the light, which is emitted from the light source22and reflected by both reflectors26L,26R, to deflection control using the lens24.

The light source22is a white light emitting diode. A light emitting chip22athereof includes a light emitting surface having a laterally long rectangular shape (e.g., a rectangle of about 1 mm in height×4 mm in width). The light source22is arranged in such a way that the light emitting chip22athereof faces a lamp front direction. The light emitting element22is fixed to a heat sink34and positioned by a light source support member32.

The lens24has a convex lens shape where the curvature of a rear surface24bis larger than that of a front surface24a. At that time, the front surface24aof the lens24is configured as a plane extending along a plane perpendicular to an axis Ax. Here, the axis Ax extends in a forward and rearward direction of the lamp so as to pass through the emission center of the light emitting chip22a. The rear surface24bof the lens24is configured as a free curved-surface which extends rearward in a convex form.

The lens24is configured as follows. A target emission angle is set in each position of the front surface24awhen the direct light emitted from the light source22is directed forward from the lens24. Then, a shape of a free curved-surface constituting the rear surface24bis set so that the direct light emitted from the light source22and reaching the lens24is incident on the lens24along an optical path corresponding to the target emission angle.

The target emission angle is set as follows. An emission angle in the lateral direction gradually increases as a position on the front surface24aof the lens24is displaced away to both left and right sides from the axis Ax. Further, an emission angle in the vertical direction gradually increases as a position on the front surface24aof the lens24is displaced away to both upper and lower sides from the axis Ax. At that time, variation in the lateral direction is set to be larger than variation in the vertical direction.

The lens24has an outer appearance of a laterally long rectangular shape, as seen from the front of the lamp. An outer peripheral edge24cof the lens24has a flange shape.

The pair of left and right reflectors26L,26R are disposed on both left and right sides of the axis Ax in the rear side of the lens24. At that time, both reflectors26L,26R are arranged in a positional relationship of bilateral symmetry about a vertical plane including the axis Ax and the reflective surfaces thereof have a bilaterally symmetrical shape. Further, each of these reflectors26L,26R is configured to reflect the direct light emitted from the light source22toward the lens24.

Each of these reflectors26L,26R is provided with a multistage reflective surface26a. The reflective surface26ais formed by performing a mirror-surface processing (such as aluminum vapor deposition) on the front surface of each reflector26L,26R. Three reflective surfaces26a1,26a2,26a3extending vertically in a stripe shape are arranged in a stepwise manner.

All of these reflective surfaces26a1,26a2,26a3are respectively configured as an inclination plane extending in a direction which spreads forward and laterally with respect to the vertical plane including the axis Ax. At that time, an inclination angle to the vertical plane including the axis Ax is set as follows. Namely, the inclination angle of the reflective surface26a1closest to the axis Ax is largest and the inclination angles of the reflective surface26a2and the reflective surface26a3are gradually reduced in this order.

The reflector26L located on the left side (on the right side, as seen from the front of the lamp), i.e., the reflector26L on the inside in the vehicle width direction is configured to emit most of the light, which is emitted from the light source22and reflected by the reflective surface26athereof, toward the outside in the vehicle width direction through the lens24. Further, the reflector26R located on the right side is configured to emit most of the light, which is emitted from the light source22and reflected by the reflective surface26athereof, toward the inside in the vehicle width direction through the lens24.

The rear surface24bof the lens24faces the pair of left and right reflectors26L,26R at positions displaced away to both left and right sides from the axis Ax. Further, reflector facing portions24bL,24bR of the rear surface24bfacing the reflective surfaces26aof respective reflectors26L,26R are formed in a horizontal cross-sectional shape having a straight line form.

A flange portion26bis respectively formed in the front ends of respective reflectors26L,26R. The flange portion26bis fixed to the outer peripheral edge24cof the lens24and fixed to the lamp body12.

The heat sink34is disposed along a plane perpendicular to the axis Ax. A plurality of cooling fins34ais formed in the rear surface of the heat sink34. An outer peripheral edge of the heat sink34is fixed to the lamp body12.

A wall surface portion16a1is formed in a region of the opening16aof the panel member16, which is located on the inside in the vehicle width direction. The wall surface portion16a1extends in the forward direction from near the outer peripheral edge of the lens24of the lamp unit20A.

Further, as shown inFIG. 1, a wall surface portion16b1is formed in a region of the opening16bof the panel member16, which is located on the inside in the vehicle width direction. The wall surface portion16b1extends in the forward direction from near the outer peripheral edge of the lens24of the lamp unit20B.

In each of the lamp units20A,20B, the light emitted forward from a left region (i.e., a region located on the inside in the vehicle width direction from the axis Ax) of the lens24thereof is directed toward the inside in the vehicle width direction. However, a portion of the light reaches the wall surface portions16a1,16a2of the panel member16and is shielded by the wall surface portions16a1,16a2.

On the other hand, in each of the lamp units20A,20B, most of the light, which is reflected by the right reflector26R and emitted forward from the lens24, is directed to the inside in the vehicle width direction. However, the emitted light is not shielded by the wall surface portions16a1,16a2of the panel member16but directed to the front region.

FIG. 5Ais a perspective view showing a high-beam light distribution pattern PH that is formed on a virtual vertical screen disposed 25 m ahead of the vehicle by the light emitted forward from the lamp unit20A located on the outside in the vehicle width direction.

The high-beam light distribution pattern PH is formed as a combined light distribution pattern of a basic light distribution pattern PO shown inFIG. 5B and two additional light distribution patterns PAL, PAR shown inFIG. 5C.

The basic light distribution pattern PO is a light distribution pattern that is formed by the direct light emitted from the light source22and reaching the lens24.

Meanwhile, the left additional light distribution pattern PAL is a light distribution pattern that is formed by the light which is emitted from the light source22, reflected by the right reflector26R and reaching the lens24. Further, the right additional light distribution pattern PAR is a light distribution pattern that is formed by the light, which is emitted from the light source22, reflected by the left reflector26L and reaching the lens24.

The basic light distribution pattern PO is formed as a laterally long light distribution pattern that is largely expanded to both left and right sides with H-V point as a center and also slightly expanded in the vertical direction with the H-V as a center. The H-V point is a vanishing point in the front direction of the lamp. The basic light distribution pattern PO has a high light-intensity zone HZ with the H-V point as a center.

However, in the basic light distribution pattern PO, a maximum spread angle to the left from V-V line is slightly smaller than a maximum spread angle to the right from the V-V line. Here, the V-V line is a vertical line passing through the H-V. Namely, the maximum spread angle to the left is set to be smaller than the spread angle indicated by a two-dot chain line inFIG. 5B. The reason is that a portion of the light emitted forward from the left region of the lens24of the lamp unit20A is shielded by the wall surface portion16a1of the panel member16.

Meanwhile, both of two additional light distribution patterns PAL, PAR are formed as a slightly laterally long light distribution pattern. At that time, these two additional light distribution patterns PAL, PAR are formed in a positional relationship of bilateral symmetry with the V-V line as a center and partially overlapped with each other at the position of the V-V line.

Also in the lamp unit20B located on the inside in the vehicle width direction, a portion of the light emitted forward from the left region of the lens24is shielded by the wall surface portion16b1of the panel member16. Accordingly, a high-beam light distribution pattern is formed like the high-beam light distribution pattern PH shown inFIG. 5.

Further, the whole light distribution pattern is formed as a high beam by the overlap of two high-beam light distribution patterns formed by the light emitted from both lamp units20A,20B.

Next, a technical effect of the present embodiment will be described.

The lamp unit20A of the vehicle lamp10according to the present embodiment is configured to form the high-beam light distribution pattern PH by controlling the deflection of the direct light emitted from the light source22using the lens24disposed on the front side thereof. However, since the pair of left and right reflectors26L,26R for reflecting the direct light from the light source22toward the lens24is disposed on the rear side of the lens24, it is possible to improve the utilization efficiency of the light emitted from the light source22by the amount of light reflected by both reflectors26L,26R.

In this way, the high-beam light distribution pattern PH can be formed as a combined light distribution pattern of the basic light distribution pattern PO, which is formed by the direct light emitted from the light source22, and the two additional light distribution patterns PAL, PAR which are formed by the light reflected by both reflectors26L,26R.

At that time, since the lens24has a convex lens shape where the curvature of the rear surface24bis larger than that of the front surface24a, it is possible to cause the light reflected by respective reflectors26L,26R to be gradually refracted on the front surface24aand the rear surface24bof the lens24. Therefore, in the light that is reflected by respective reflectors26L,26R and incident on the lens24, the percentage of the light that is totally reflected on the front surface24aof the lens24can be reduced to zero or the percentage can be significantly reduced as compared to the prior art configuration. Thus, it is possible to sufficiently improve the light emission efficiency from the lens24.

Accordingly, it is possible to sufficiently secure the brightness of the high-beam light distribution pattern PH with two reflectors26L,26R.

According to the present embodiment as described above, in the vehicle lamp20A configured to form the high-beam light distribution pattern PH by controlling the deflection of the direct light emitted from the light source22using the lens24disposed on the front side thereof, it is possible to sufficiently secure the brightness of the high-beam light distribution pattern PH with two reflectors26L,26R.

Furthermore, in the lamp unit20A according to the present embodiment, the curvature of the rear surface24bof the lens24is larger than that of the front surface24aand therefore it is possible to easily secure a space for placing both reflectors26L,26R. Thereby, it is possible to prevent, in advance, the size of the lamp unit20A from being increased.

In the lamp unit20A according to the present embodiment, each of the reflectors26L,26R has the multistage reflective surface26aand therefore it is possible to finely control the size and forming position of the additional light distribution patterns PAR, PAL, which are formed by the light reflected by the reflective surface26a. Thereby, it is possible to reduce the light unevenness of the high-beam light distribution pattern PH.

Further, in the lamp unit20A according to the present embodiment, the reflector facing portions24bL,24bR of the rear surface24bof the lens24facing the reflective surfaces26aof respective reflectors26L,26R have a horizontal cross-sectional shape having a straight line form. Accordingly, it can be easily prevented that the light reflected by respective reflectors26L,26R is largely refracted on the rear surface24bof the lens24and totally reflected on the front surface24aof the lens24.

Even in the case where the horizontal cross-sectional shape of respective reflector facing portions24bL,24bR is not a pure straight line but a curve close to a straight line, the same operational effects can be obtained.

Furthermore, in the present embodiment, the panel member16is disposed around the lens24of the lamp unit20A and therefore it is possible to improve the design of the lamp.

At that time, the wall surface portion16a1is formed in a region of the opening16aof the panel member16, which is located on the inside in the vehicle width direction. The wall surface portion16a1extends in the forward direction from near the outer peripheral edge of the lens24of the lamp unit20A. However, the reflective surface26aof the right reflector26R disposed on the outside (i.e., opposite side of the wall surface portion16a1about the axis Ax) in the vehicle width direction is formed in such a way that the light emitted from the light source22and reflected by the reflective surface26ais directed toward the inside (i.e., the direction of the wall surface portion16a1about the axis Ax) in the vehicle width direction from the lens24. Accordingly, the following technical effects can be obtained.

Namely, when a portion of the light emitted from the lens24is shielded by the wall surface portion16a1of the panel member16, the brightness of the left end portion (i.e., end portion on the inside in the vehicle width direction where the wall surface portion16a1is disposed) of the high-beam light distribution pattern PH is lowered. On the contrary, in the present embodiment, the light reflected by the reflector26R is emitted toward the inside in the vehicle width direction from the lens24and therefore the light reflected by the reflector26R can compensate the brightness corresponding to the amount of light shielded by the wall surface portion16a1of the panel member16. Accordingly, it is possible to prevent, in advance, the brightness of the left end portion of the high-beam light distribution pattern PA from being inadvertently lowered. As a result, it is possible to form the high-beam light distribution pattern PA with a desired brightness.

In the present embodiment, the pair of left and right reflectors26L,26R is disposed on the rear side of the lens24and on both left and right sides of the axis Ax and arranged in a shape and positional relationship of bilateral symmetry. Accordingly, when observing the lamp unit20A from the front of the lamp, the reflective surfaces26aof both reflectors26L,26R can be seen in the shape and positional relationship of bilateral symmetry though the lens24. In this way, it is possible to improve the appearance of the lamp unit20A. Furthermore, since each of the reflective surfaces26aof both reflectors26L,26R includes three reflective surfaces26a1,26a2,26a3configured as a multistage reflective surface arranged in a vertical stripe, it is possible to sufficiently improve the appearance of the lamp unit20A.

In the present embodiment, the lamp unit20B can also obtain the same technical effects as those of the lamp unit20A.

Although, in the present embodiment, the lens24of respective lamp units20A,20B has an outer appearance of a laterally long rectangular shape, as seen from the front of the lamp, the lens24may have an outer appearance (e.g., a circular shape or elliptical shape, etc.) other than the laterally long rectangular shape.

Although, in the present embodiment, each of the lamp units20A,20B includes a pair of left and right reflectors26L,26R, each of the lamp units20A,20B may include only one of both reflectors. Although, in the present embodiment, each of the reflectors26L,26R is provided with the multistage reflective surface26a, each of the reflectors26L,26R may be provided with a single reflective surface. Furthermore, although, in the present embodiment, each of the reflectors26L,26R is provided at the front surface thereof with the reflective surface26athat is mirror-surface processed, a configuration that fine reflective particles are included into the transparent member may be employed.

Although, in the present embodiment, the vehicle lamp10includes two lamp units20A,20B, the vehicle lamp10may include only the lamp unit20A or include a lamp unit other than the lamp units20A,20B.

Although, in the present embodiment, the vehicle lamp10is a high-beam headlamp provided on the right front end of a vehicle, the vehicle lamp10may be configured as a high-beam headlamp provided on the left front end of a vehicle, configured as a headlamp for forming a low-beam light distribution pattern or configured as a fog lamp or a daytime running lamp.

Next, a modification of the above-described embodiment will be described.

FIG. 6is a view similar toFIG. 2, showing a vehicle lamp110according to the modification of the embodiment.

As shown inFIG. 6, a basic configuration of the vehicle lamp110is the same as the above-described embodiment, but a configuration of a lens124in a lamp unit120A thereof is partially different from the above-described embodiment.

Namely, in the lens124of the present modification, both a front surface124aand a rear surface124bthereof are formed in a convex curved surface. At that time, the curvature of the rear surface124bis set to be larger than that of the front surface24a.

The lens124is configured as follows. A target emission angle is set in each position of the front surface124awhen the direct light emitted from the light source22is directed forward through the lens124. Then, a shape of a free curved-surface constituting the rear surface124bis set so that the direct light emitted from the light source22and reaching the lens124is incident on the lens124along an optical path corresponding to the target emission angle.

At that time, of the rear surface124bof the lens124, reflector facing portions124bL,124bR facing the reflective surfaces26aof respective reflectors26L,26R are formed in a horizontal cross-sectional shape having a straight line form.

With the configuration of the present modification, it is possible to obtain the same technical effects as the above-described embodiment.

Of course, the numerical values represented as specifications in the above-described embodiments and modifications thereof are merely examples and may be set to different values, as appropriate.

Further, the present invention is not limited to the configurations described in the above-described embodiments and modifications thereof but may employ other configurations that are variously changed from the configurations.