VEHICLE LIGHTING FIXTURE

A vehicle lighting fixture is capable of forming a light distribution pattern with higher light intensity while suppressing generation of glare light. A vehicle lighting fixture can include two light sources; a center reflecting surface having a focal line passing through centers of emission faces of the two light sources; lateral reflecting surfaces extending from respective lateral edges of the center reflecting surface and each obtained by moving a parabola obliquely sideward, with the parabola having a focal point located at a farthest front corner of the emission face of the closer point light source; and plate reflecting surfaces forming a substantially L-letter shape with a bent point interposed therebetween and each formed from a paraboloidal columnar surface obtained by moving a parabola obliquely forward and downward, with the parabola having a focal point located at a farthest front corner of the emission face of the closer point light source.

This application claims the priority benefit under 35 U.S.C. §119 of Japanese Patent Application No. 2015-060860 filed on Mar. 24, 2015, which is hereby incorporated in its entirety by reference.

TECHNICAL FIELD

The presently disclosed subject matter relates to vehicle lighting fixtures, and in particular, to a vehicle lighting fixture capable of forming desired light distribution characteristics by light rays that are emitted from a plurality of light sources and reflected by a plurality of reflecting surfaces.

BACKGROUND ART

Conventional vehicle lighting fixtures of this type include those disclosed in Japanese Patent Application Laid-Open No. 2013-191325 as a “vehicle headlight,” which corresponds to US2013/0235601A1.

FIGS. 1A to 1Care a schematic configuration diagram of a vehicle headlight80disclosed in the publication, a diagram illustrating how a light source81emits light rays, and a diagram illustrating how a light source83emits light rays, respectively. As illustrated in these drawings, the vehicle headlight80includes three light sources81,82, and83. The light source81can be disposed at a focal point of a paraboloidal mirror85, and the other two light sources82and83can be disposed at respective positions different from the focal point of the paraboloidal mirror85. Light rays emitted from the respective light sources81,82, and83can be reflected by the paraboloidal mirror85to be projected at respective different ranges, thereby forming a desired light distribution pattern.

In the vehicle headlight80with the above-mentioned configuration, the light rays emitted by the plurality of light sources81,82, and83and reflected by the paraboloidal mirror85can be projected to respective different target positions to enlarge the formation region of the light distribution pattern. Thus, there is no challenge to improve the light distribution pattern with higher light intensity.

SUMMARY

The presently disclosed subject matter was devised in view of these and other problems and features in association with the conventional art. According to an aspect of the presently disclosed subject matter, a vehicle lighting fixture can be configured to be capable of forming a desired light distribution pattern with higher light intensity by light rays that are emitted from a plurality of light sources and reflected by a plurality of reflecting surfaces while suppressing generation of glare light.

According to another aspect of the presently disclosed subject matter, a vehicle lighting fixture can include two point light sources; a reflector having reflecting surfaces configured to reflect light rays emitted from the two light sources; and a light shielding member configured to shield part of the light rays emitted from the two light sources. In the vehicle lighting fixture, the two point light sources can each have an emission face, and be disposed on a same plane so that the emission faces face in a same direction. The reflecting surfaces of the reflector can include a center reflecting surface disposed below the two point light sources and lateral reflecting surfaces on both sides of the center reflecting surface, the lateral reflecting surfaces each including a center part. The light shielding member can be disposed on straight lines each connecting any one of the two point light sources and the center part of any farther one of the lateral reflecting surfaces with respect to the one point light source. The lateral reflecting surfaces can each be formed from a curved columnar surface obtained by moving a parabola obliquely sideward, with the parabola having a focal point located at a farthest front corner of the emission face of the point light source on a side closer to the lateral reflecting surface of interest.

According to still another aspect of the presently disclosed subject matter, the vehicle lighting fixture according to the previous aspect can be configured such that the light shielding member can include a reflecting surface in substantially an L-letter shape, and parts of the reflecting surface on both extension sides of the L-letter shape can be formed from a paraboloidal columnar surface obtained by moving a parabola obliquely forward and downward, with the parabola having a focal point located at a farthest front corner of the emission face of the point light source on a side closer to the part of the L-letter shaped reflecting surface of interest.

In the vehicle lighting fixture with the above-mentioned configuration, the point light source can be a light emitting diode (LED).

According to the presently disclosed subject matter, the center reflecting surface disposed below the two point light sources can be formed from a paraboloidal columnar surface obtained by laterally moving a parabola having an axis inclined forward and downward, with the parabola having a focal line passing through centers of the emission faces of the two point light sources so as to reflect the light rays emitted from the two point light sources to a forward and downward position in front of the vehicle lighting fixture. Furthermore, the lateral reflecting surfaces disposed on both the sides of the center reflecting surface can be configured to reflect the light rays emitted from the two point light sources to a forward, inward and downward position in front of the vehicle lighting fixture. Further, the light shielding portion can be configured to shield the light rays emitted from the two point light sources and directed to any farther one of the lateral reflecting surfaces.

The vehicle lighting fixture with this configuration can prevent the generation of glare light thereby ensuring front visibility of a driver of an oncoming vehicle.

Furthermore, the light shielding member can include the reflecting surface configured to reflect the light rays emitted from the point light sources to forward, downward and outward positions. As a result, the vehicle lighting fixture can suppress the generation of glare light while providing the desired light distribution pattern with higher light intensity.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

A description will now be made below to a vehicle lighting fixture of the presently disclosed subject matter with reference to the accompanying drawings in accordance with exemplary embodiments.

FIG. 2is a perspective view of a vehicle lighting fixture1made in accordance with the principles of the presently disclosed subject matter when observed from an obliquely upper position.FIGS. 3 and 4are a front view and a top view of the vehicle lighting fixture1, respectively.FIG. 5is a diagram illustrating emission light rays from the light sources.FIGS. 6A to 6Dare diagrams each illustrating a light distribution pattern formed on a virtual vertical screen.

The vehicle lighting fixture1(hereinafter, simply referred to as “lighting fixture”) can be configured to a lighting apparatus to be attached to a front part of a vehicle body while the light irradiation direction thereof is directed forward of the vehicle body. Accordingly, the terms for describing directions of “front (forward),” “back (rearward),” “lateral (left, right),” “up (upward),” and “down (low, downward)” mean “a forward direction,” “rearward direction,” widthwise direction,” “upper direction,” and “lower direction” with respect to the vehicle body on which the lighting fixture1is installed.

The lighting fixture1of the presently disclosed subject matter can include two light sources2and3, a single reflector10configured to have a reflecting function, and a single bent plate30configured to have both a light shielding function and a reflecting function. The respective components can be disposed in a bilaterally symmetric manner along the lateral direction.

As the light sources2and3, there can be adopted a light source that can be configured to have a size substantially considered as an optically point light source with respect to an optical system including the reflector10and the bent plate30. Specific examples thereof may include a light emitting diode (LED), which is used in the present exemplary embodiment. When the color of the lighting fixture10is needed to be white, the LED can a device including a blue LED element configured to emit blue light and a yellow wavelength converting phosphor configured to emit yellow light as a result of excitation by blue light in combination. This device can emit white light (pseud white light) by color mixing of part of blue light from the blue LED element and yellow light derived from the phosphor excited by another part of the blue light.

The light sources2and3can be disposed at respective left and right-side points with a predetermined gap therebetween.

The reflector10can include a center reflecting surface15positioned at center and two lateral reflecting surfaces20and25positioned on both sides of the center reflecting surface15.

Among them, the center reflecting surface15can be disposed and extend from a position rearward and obliquely downward with respect to the light sources2and3to a position forward and obliquely downward via a position below the light sources2and3. As a result, the entire shape of the center reflecting surface15can be a recessed curved shape extending from the rear position to the front position. Specifically, the center reflecting surface15can be formed from a paraboloidal columnar surface obtained by laterally moving a parabola having an axis inclined forward and downward, with the parabola having a focal point at a center2C of an emission face2aof the light source2or a center3C of an emission face3aof the light source3.

Thus, the center reflecting surface15can have the paraboloidal columnar surface shape having a focal line4passing through the centers2C and3C of the emission faces2aand3aof the two point light sources2and3and the axis inclined forward and downward so as to reflect the light rays emitted from the two point light sources2and3to a forward and downward position in front of the vehicle lighting fixture1.

The lateral reflecting surfaces20and25can obliquely laterally extend from each of lateral edges of the center reflecting surface to be formed as a recessed curved shape. Specifically, the lateral reflecting surfaces20and25can each be formed from a curved columnar surface obtained by moving a parabola obliquely sideward, with the parabola having a focal point located at a farthest front corner2P,3P of the emission face2a,3aof the point light source2,3on a side closer to the lateral reflecting surface20,25of interest and with an axis inclined forward, inward and downward.

In other words, the lateral reflecting surfaces20and25can each be a curved columnar surface having a focal line5,6on a virtual line passing the farthest front corner2P,3P of the emission face2a,3aof the point light source2,3on a side closer to the lateral reflecting surface20,25of interest and extending obliquely laterally and with the axis inclined forward, inward and downward.

The bent plate30can be formed to have a substantially L-letter shape including plate portions35and40with a bent point interposed therebetween, having respective plate reflecting surfaces36and41while the bent point is located forward. The reflecting surface36,41can be configured to be curved in a width direction and be concave rearward. The one plate portion35can be positioned on or near a line connecting the light source2and a center portion of the lateral reflecting surface25farther from the light source2while the other plate portion40can be positioned on or near a line connecting the light source3and a center portion of the lateral reflecting surface20farther from the light source3.

The plate reflecting surfaces36and41can each be formed from a paraboloidal columnar surface obtained by moving a parabola obliquely forward and downward, with the parabola having a focal point located at a farthest front corner2Q,3Q of the emission face2a,3aof the point light source2,3on a side closer to the plate reflecting surface36,41of interest and with the axis inclined forward, outward and downward.

In other words, the plate reflecting surfaces36and41can each be a paraboloidal columnar surface having a focal line7,8on a virtual line passing the farthest front corner2Q,3Q of the emission face2a,3aof the point light source2,3on a side closer to the plate reflecting surface36,41of interest and extending obliquely laterally and with the axis inclined forward, outward and downward.

A description will next be given of how the optical paths for the emission light rays from the respective light sources2and3can be formed by the optical system including the reflector10and the bent plate30.

Light rays emitted from the light source2can mainly be directed to the center reflecting surface15and the lateral reflecting surface20of the reflector10and the plate reflecting surface36of the plate portion35of the bent plate30. On the other hand, light rays emitted from the light source3can mainly be directed to the center reflecting surface15and the lateral reflecting surface25of the reflector10and the plate reflecting surface41of the plate portion40of the bent plate30.

Specifically, light rays L21and L31emitted from the light sources2and3located on the focal line4of the paraboloidal columnar shaped center reflecting surface15and directed to the center reflecting surface15can be incident on the center reflecting surface15and reflected by the same. Then, the reflected light rays can be diffused laterally while the diffusion in the vertical direction is suppressed. As a result, the light rays can be projected to a forward and downward position in front of the vehicle lighting fixture1.

When the projected image of the light rays is projected and observed on a virtual vertical screen (with a horizontal reference line H and a vertical reference line V) disposed in front of the vehicle lighting fixture1, a light distribution pattern16as illustrated inFIG. 6Acan be obtained. Specifically, the light distribution pattern16illustrated can be spread laterally long with a predetermined vertical width while projected below the horizontal reference line H and across the vertical reference line V.

Next, light rays122emitted from the light source2located on the focal line5of the curved columnar shaped lateral reflecting surface20with the farthest front corner2P of the emission face2awith respect to the lateral reflecting surface20being the focal point thereof and directed to the lateral reflecting surface20can be incident on the lateral reflecting surface20and reflected by the same. Then, the reflected light rays can be diffused laterally while the diffusion in the vertical direction is suppressed. As a result, the light rays can be projected to a forward, inward, and downward position in front of the vehicle lighting fixture1.

On the other hand, light rays L32emitted from the light source3located on the focal line6of the curved columnar shaped lateral reflecting surface25with the farthest front corner3P of the emission face3awith respect to the lateral reflecting surface25being the focal point thereof and directed to the lateral reflecting surface25can be incident on the lateral reflecting surface25and reflected by the same. Then, the reflected light rays can be diffused laterally while the diffusion in the vertical direction is suppressed. As a result, the light rays can be projected to a forward, inward, and downward position in front of the vehicle lighting fixture1.

When the projected images of the light rays from the lateral reflecting surfaces20and25are projected and observed on the virtual vertical screen disposed in front of the vehicle lighting fixture1, light distribution patterns21and26as illustrated inFIG. 6Bcan be obtained. Specifically, the light distribution pattern21illustrated can be spread laterally long with a predetermined vertical width while projected below the horizontal reference line H and on one side with respect to the vertical reference line V. Furthermore, the light distribution pattern26illustrated can be spread laterally long with a predetermined vertical width while projected below the horizontal reference line H and on the other side with respect to the vertical reference line V.

That is, the light distribution patterns21and26can be located at respective symmetric positions with respect to the vertical reference line V.

Next, light rays L23emitted from the light source2located on the focal line7of the paraboloidal columnar shaped plate reflecting surface36with the farthest front corner2Q of the emission face2awith respect to the plate reflecting surface36being the focal point thereof and directed to the plate reflecting surface36can be incident on the plate reflecting surface36and reflected by the same. Then, the reflected light rays can be diffused laterally while the diffusion in the vertical direction is suppressed. As a result, the light rays can be projected to a forward, outward, and downward position in front of the vehicle lighting fixture1.

On the other hand, light rays L33emitted from the light source3located on the focal line8of the paraboloidal columnar shaped plate reflecting surface41with the farthest front corner3Q of the emission face3awith respect to the plate reflecting surface41being the focal point thereof and directed to the plate reflecting surface41can be incident on the plate reflecting surface41and reflected by the same. Then, the reflected light rays can be diffused laterally while the diffusion in the vertical direction is suppressed. As a result, the light rays can be projected to a forward, outward, and downward position in front of the vehicle lighting fixture1.

When the projected images of the light rays from the plate reflecting surfaces36and41are projected and observed on the virtual vertical screen disposed in front of the vehicle lighting fixture1, light distribution patterns37and42as illustrated inFIG. 6Ccan be obtained. Specifically, the light distribution pattern37illustrated can be spread laterally long with a predetermined vertical width while projected below the horizontal reference line H and on one side with respect to the vertical reference line V. Furthermore, the light distribution pattern42illustrated can be spread laterally long with a predetermined vertical width while projected below the horizontal reference line H and on the other side with respect to the vertical reference line V.

Accordingly, when the light distribution pattern16formed by the center reflecting surface15, the light distribution patterns21and26formed by the respective lateral reflecting surfaces20and25, and the light distribution patterns37and42formed by the respective plate reflecting surfaces36and41are observed on the same virtual vertical screen, a resulting light distribution pattern can be formed on the screen as illustrated inFIG. 6D.

Specifically illustrated inFIG. 6D, the light distribution pattern16can be formed below the horizontal reference line H and across the vertical reference line V. Furthermore, a synthesis light distribution pattern50can be formed by overlaying the light distribution patterns21and42on each other below the horizontal reference line H and on the one side with respect to the vertical reference line V. Another synthesis light distribution pattern51can be formed by overlaying the light distribution patterns26and37on each other below the horizontal reference line H and on the other side with respect to the vertical reference line V.

The synthesis light distribution pattern50and the light distribution pattern16can be overlaid in part so that the synthesis light distribution pattern50can extend outward from the one end of the light distribution pattern16. On the other hand, the synthesis light distribution pattern51and the light distribution pattern16can be overlaid in part so that the synthesis light distribution pattern50can extend outward from the other end of the light distribution pattern16. As a result, the synthesis light distribution pattern50, the light distribution pattern16, and the synthesis light distribution pattern51can form an integral light distribution pattern laterally long below the horizontal reference line11and across the vertical reference line V as illustrated inFIG. 6D.

In this case, the synthesis light distribution pattern50, the light distribution pattern16, and the synthesis light distribution pattern51can each be formed by light rays emitted from the two light sources2and3. Thus, each of the light distribution patterns50,16, and51can be formed with high light intensity, thereby achieving the entire light distribution pattern with high light intensity over the entire region thereof.

Incidentally, if the plate reflecting surface36is not included (or the plate portion35is not included), the light rays emitted from the light source2and directed to the position of the not-included plate reflecting surface36can travel to the farther lateral reflecting surface25with respect to the light source2and be reflected by the same to form a light distribution pattern above the horizontal reference line H. Similarly, if the plate reflecting surface41is not included (or the plate portion40is not included), the light rays emitted from the light source3and directed to the position of the not-included plate reflecting surface41can travel to the farther lateral reflecting surface20with respect to the light source3and be reflected by the same to form a light distribution pattern above the horizontal reference line H. The resulting light distribution pattern includes the light components above the horizontal reference line H, resulting in generation of glare light to an oncoming vehicle and the like and deterioration of front visibility of a driver of an oncoming vehicle.

On the contrary, the lighting fixture according to the present exemplary embodiment can include the bent plate30on the optical paths, through which light rays emitted from the light sources2and3can pass to become glare light if there is no bent plate30. Thus, the lighting fixture with the bent plate can prevent the generation of glare light by shielding light rays with the bent plate30while the shielded light rays can be effectively utilized by being reflected by the bent plate30. The effective use of the light rays can increase the utilization efficiency of light and improve the light distribution pattern with higher light intensity.

Furthermore, the focal points of the curved columnar shaped lateral reflecting surfaces20and25can be disposed at the respective farthest front corners2P and3P of the emission faces2aand3aof the light sources2and3with respect to the lateral reflecting surfaces20and25of interest. This means that the respective lateral reflecting surfaces20and25can project the images formed at the respective focal points at the upper edges of the light distribution patterns21and26(or on the respective cut-off lines thereof). Therefore, since the respective farthest front corners2P and3P with respect to the lateral reflecting surfaces20and25of interest forming the upper edges of the light distribution patterns21and26can be at the same positions as the respective focal points thereof, light rays above the cut-off line can be prevented from being projected, thereby preventing the generation of glare light.

The focal points of the paraboloidal columnar shaped plate reflecting surfaces36and41can be disposed at the respective farthest front corners2Q and3Q of the emission faces2aand3aof the light sources2and3with respect the plate reflecting surfaces36and41of interest. This means that the respective plate reflecting surfaces36and41can project the images formed at the respective focal points at the upper edges of the light distribution patterns37and42(or on the respective cut-off lines thereof). Therefore, since the respective farthest front corners2Q and3Q with respect to the plate reflecting surfaces36and41of interest forming the upper edges of the light distribution patterns37and42can be at the same positions as the respective focal points thereof, light rays above the cut-off line can be prevented from being projected, thereby preventing the generation of glare light.

Note that the bent plate may not be provided with a reflecting surface, and may only serve as a light shielding member. In this case, also the vehicle lighting fixture can prevent the generation of glare light thereby ensuring front visibility of a driver of an oncoming vehicle.

It will be apparent to those skilled in the art that various modifications and variations can be made in the presently disclosed subject matter without departing from the spirit or scope of the presently disclosed subject matter. Thus, it is intended that the presently disclosed subject matter cover the modifications and variations of the presently disclosed subject matter provided they come within the scope of the appended claims and their equivalents. All related art references described above are hereby incorporated in their entirety by reference.