JP4279183B2 - Vehicle headlamp - Google Patents

Description

  The present invention relates to a so-called projector-type vehicle headlamp.

  In general, a projector-type vehicle headlamp has a projection lens disposed on an optical axis extending in the longitudinal direction of the vehicle, and a light source disposed behind the rear focal point. The reflector is configured to reflect near the optical axis.

  In “Patent Document 1” and “Patent Document 2”, in such a projector-type vehicle headlamp, the light source is emitted by a light-emitting portion of a light source bulb inserted and fixed to a reflector from the side of the optical axis. A so-called side-insertion type lamp configuration is described.

  Further, in “Patent Document 3”, in a normal projector-type vehicle headlamp in which a light source bulb is inserted and fixed to the reflector from behind, the light from the light source is not transmitted through the projection lens below the light source. Describes a lamp configuration in which an additional reflector that reflects the light forward is disposed.

Japanese Utility Model Publication No. 2-47704 JP 2001-229715 A JP-A-62-15701

  If a side-insertion-type lamp configuration is employed in a projector-type vehicle headlamp, the front-and-rear length of the lamp can be shortened to make it compact.

  However, in the vehicle headlamps described in the above-mentioned “Patent Document 1” and “Patent Document 2”, the light source bulb is inserted and fixed to the reflector on the same horizontal plane as the optical axis. There is.

  That is, in a projector-type vehicle headlamp, the region on the side of the optical axis on the reflecting surface of the reflector is suitable for forming a diffusion region of the light distribution pattern, but the light source bulb is on the same horizontal plane as the optical axis. If the light source bulb is inserted and fixed in the reflector, a hole for inserting and fixing the light source bulb is formed in the optical axis side region of the reflecting surface. Therefore, the optical axis side region is effectively used for light distribution control. Therefore, there is a problem that it is difficult to ensure sufficient brightness of the diffusion region of the light distribution pattern.

  Therefore, if a configuration including an additional reflector as described in the above-mentioned “Patent Document 3” is adopted after adopting a side-insertion-type lamp configuration, only an increase in the amount of reflected light from the additional reflector is obtained. The brightness of the diffusion region of the light distribution pattern can be improved.

  However, in the vehicle headlamp described in the above “Patent Document 3”, since the light source bulb is disposed on the optical axis, the light from the light source does not pass through the projection lens by the additional reflector and moves forward. In order to reflect the light toward the light source, it is necessary to arrange the additional reflector at a position far away from the light source, and the solid angle is not so large. For this reason, an increase in the amount of light due to the reflected light from the additional reflector cannot be expected so much, and there is a problem that it is still insufficient to sufficiently secure the brightness of the diffusion region of the light distribution pattern.

  The present invention has been made in view of such circumstances, and even in the case where a side-insertion type lamp configuration is adopted in a projector-type vehicle headlamp, the diffusion region of the light distribution pattern can be reduced. It is an object of the present invention to provide a vehicular headlamp that can sufficiently ensure brightness.

  According to the present invention, the above-described object is achieved by contriving the insertion and fixing position of the light source bulb with respect to the reflector and by providing a predetermined additional reflector.

That is, the vehicle headlamp according to the present invention is
A projection lens disposed on the optical axis extending in the vehicle front-rear direction, a light source disposed rearward of the rear focal point of the projection lens, and light from this light source is reflected toward the optical axis toward the front. A vehicle headlamp comprising a reflector to be
The light source is composed of a light emitting part of a light source bulb inserted and fixed to the reflector from the side of the optical axis at a position spaced downward from the optical axis,
An additional reflector that reflects light from the light source forward without passing through the projection lens is disposed below the light source ,
The reflection surface of the additional reflector is configured such that the upper region reflects light from the light source downward than the lower region of the reflection surface,
The vertical sectional shape of the reflection surface of the additional reflector is a substantially elliptical shape having the position of the light source as the first focal point and the position below the lower edge of the additional reflector in front of the projection lens as the second focal point. It is characterized by being set .

  The light distribution pattern formed by light irradiation from the vehicle headlamp according to the present invention may be a low-beam light distribution pattern, a high-beam light distribution pattern, or any other distribution. It may be a light pattern.

  The type of the “light source bulb” is not particularly limited, and for example, a discharge bulb, a halogen bulb, or the like can be adopted.

  The light source bulb is inserted and fixed to the reflector at a “position away from the optical axis”, but the amount of downward displacement of the insertion fixed position from the optical axis is not particularly limited. At that time, in order to prevent the light from the light source bulb reflected in the region near the optical axis on the reflecting surface of the reflector from being blocked by the light source bulb, the downward displacement is set to a value of 10 mm or more. It is preferable to set the value to 15 mm or more. On the other hand, from the viewpoint of sufficiently securing the incident light flux from the light source bulb to the reflecting surface of the reflector, it is preferable to set the downward displacement amount to a value of 30 mm or less.

  The “reflector” and “additional reflector” may be formed integrally or may be formed separately.

  As shown in the above configuration, the vehicular headlamp according to the present invention is configured as a projector-type vehicular headlamp, and its light source bulb is inserted into the reflector from the side of the optical axis extending in the vehicle front-rear direction. Since it is fixed, the front-rear length of the lamp can be shortened to make it compact.

  At this time, since the light source bulb is inserted and fixed at a position away from the optical axis, the area on the side of the optical axis on the reflecting surface of the reflector can be effectively used for light distribution control. Then, a diffusion region of the light distribution pattern can be formed by the reflected light from the optical axis side region, and sufficient brightness can be secured in the diffusion region.

  Further, in the vehicle headlamp according to the present invention, an additional reflector that reflects light from the light source forward without passing through the projection lens is disposed below the light source. The additional light distribution pattern formed by the reflected light from the reflector is added to the basic light distribution pattern formed by the light reflected by the reflector and transmitted through the projection lens. The brightness of the entire light distribution pattern formed by light irradiation can be sufficiently secured.

  At this time, since the light source is disposed at a position away from the optical axis, the additional reflector can be disposed close to the light source, and a large solid angle can be secured. As a result, a sufficient light source beam incident on the additional reflector can be ensured, and the additional light distribution pattern can be made sufficiently bright.

  As described above, according to the present invention, it is possible to sufficiently ensure the brightness of the diffusion region of the light distribution pattern even when the side-insertion-type lamp configuration is adopted in the projector-type vehicle headlamp. it can.

  In that case, in the present invention, by performing insertion and fixing of the light source bulb at a position away from the optical axis, sufficient brightness can be secured in the diffusion region of the light distribution pattern. The light distribution pattern is not necessarily formed as a horizontally long light distribution pattern, and may be formed as a light distribution pattern for condensing that hardly diffuses in the left-right direction.

  In the above configuration, if a shade for shielding a part of the reflected light from the reflector is arranged in the vicinity of the rear focal point of the projection lens so that the upper end edge thereof is positioned in the vicinity of the optical axis, the cut off line is provided at the upper end edge. In this case, a part of the light source luminous flux is lost due to the presence of the shade, so that the remaining light source luminous flux is obtained by adopting the configuration of the present invention. The effective use of is particularly effective in ensuring sufficient brightness of the light distribution pattern for low beam.

  Even in the case where the shade is provided in this way, the additional reflector is disposed below the light source. Therefore, it is easy to control the reflected light by the additional reflector without being hindered by the presence of the shade. It becomes possible.

  In the above configuration, when the light source is configured as a line light source extending in the bulb central axis direction of the light source bulb, the image of the light source formed by the reflected light from the additional reflector is a horizontally long image as a whole. Thus, the vertical width of the additional light distribution pattern can be reduced, thereby preventing the short distance area on the road surface ahead of the vehicle from becoming excessively bright.

In the present invention, the reflective surface of the additional reflector, since towards the upper region than the lower region of the reflecting surface is configured to reflect light from the light source downward, the following effects Obtainable.

  That is, on the reflection surface of the additional reflector, the upper region is closer to the light source than the lower region, so that the image of the light source formed by the reflected light from the upper region is relatively large. Therefore, if the reflecting surface of the additional reflector is configured so that the light from the light source is reflected downward in the upper region than in the lower region, the additional light distribution pattern is gradually increased from the lower end edge toward the upper end edge. Therefore, it is possible to irradiate the road surface in front of the vehicle substantially uniformly from the short distance area to the far distance area, thereby further improving the visibility.

In this case, in the present invention, the vertical cross-sectional shape of the reflecting surface of the additional reflector has the position of the light source as the first focal point and the position below the lower edge of the additional reflector in front of the projection lens as the second focal point. Therefore , the light intensity change in the vertical direction of the additional light distribution pattern can be made smoother, thereby further improving the visibility of the road surface in front of the vehicle.

  In the above configuration, if the reflection surface of the additional reflector is configured to reflect the light from the light source toward the optical axis in the left-right direction, the reflected light from the additional reflector is once converged and then diffused in the left-right direction. Therefore, the additional light distribution pattern can be formed as a horizontally long light distribution pattern while preventing the reflected light from the additional reflector from being inadvertently blocked by another lamp component member.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  First, a first embodiment of the present invention will be described.

  FIG. 1 is a side sectional view showing a vehicle headlamp according to the present embodiment.

  As shown in the figure, a vehicle headlamp 10 according to this embodiment includes a front and rear of a vehicle in a lamp chamber formed by a lamp body 12 and a transparent translucent cover 14 attached to a front end opening of the lamp body 12. A lamp unit 20 having an optical axis Ax extending in the direction is accommodated via an aiming mechanism 50 so as to be tiltable in the vertical direction and the horizontal direction. When the aiming adjustment by the aiming mechanism 50 is completed, the lamp unit 20 has its optical axis Ax extending in a downward direction by about 0.5 to 0.6 ° with respect to the vehicle longitudinal direction. .

  An inner panel 16 is provided along the translucent cover 14 in the lamp chamber. In the inner panel 16, a vertically long opening 16 a is formed so as to surround the lamp unit 20.

  FIG. 2 is a side sectional view showing the lamp unit 20 as a single item, and FIGS. 3 and 4 are plan sectional views showing the lamp unit 20 as a single item.

  As shown in these drawings, the lamp unit 20 is a projector-type lamp unit, and includes a light source bulb 22, a reflector 24, a holder 26, a projection lens 28, a shade 32, and an additional reflector 34. It is prepared.

  The projection lens 28 is a plano-convex lens having a convex front surface and a flat rear surface, and is disposed on the optical axis Ax. The projection lens 28 projects the image on the focal plane including the rear focal point F forward as a reverse image.

  The light source bulb 22 is a discharge bulb such as a metal halide bulb having a discharge light emitting portion as a light source 22a. The light source 22a is configured as a line segment light source extending in the bulb center axis Ax1 direction of the light source bulb 22. The light source bulb 22 is located behind the rear focal point F of the projection lens 28 and away from the optical axis Ax (for example, a position away from the optical axis Ax by about 20 mm) at the optical axis Ax. Are inserted and fixed to the reflector 24 from the right side. This insertion and fixing is performed by positioning the central position of the light source 22a vertically below the optical axis Ax in a state where the bulb central axis Ax1 is set to extend in the horizontal direction in a vertical plane orthogonal to the optical axis Ax. It has been broken.

  The reflector 24 has a reflecting surface 24a that reflects light from the light source bulb 22 forward and toward the optical axis Ax. The reflecting surface 24a has a substantially elliptical cross-sectional shape, and its eccentricity is set to gradually increase from the vertical cross section toward the horizontal cross section. As a result, as shown in FIGS. 2 and 3, the light from the light source 22a reflected by the reflecting surface 24a is substantially converged in the vicinity of the rear focal point F in the vertical section, and is converged in the horizontal section. The position is moved forward considerably.

  In the reflector 24, a valve insertion fixing portion 24 b is formed in the lower right region of the reflection surface 24 a so as to protrude from the reflection surface 24 a, and a valve insertion hole 24 c is formed in the left side surface portion of the valve insertion fixing portion 24 b. Is formed. The reflector 24 is supported by the lamp body 12 via an aiming mechanism 50 in aiming brackets 24d formed at the three locations.

  The holder 26 is formed so as to extend in a substantially cylindrical shape from the front end opening of the reflector 24 toward the front. The holder 26 is fixedly supported by the reflector 24 at the rear end and fixedly supports the projection lens 28 at the front end. is doing.

  The shade 32 is formed integrally with the holder 26 so as to be positioned in a substantially lower half portion in the internal space of the holder 26. The shade 32 is formed such that its upper edge 32 a passes through the rear focal point F of the projection lens 28, thereby blocking a part of the reflected light from the reflection surface 24 a of the reflector 24, thereby projecting the projection lens 28. Most of the upward light emitted forward from is removed.

  The additional reflector 34 is disposed below the light source 22a between the reflector 24 and the projection lens 28, and reflects the light from the light source 22a forward without passing through the projection lens 28. ing. The additional reflector 34 is fixed to the bottom wall 24 e of the reflector 24.

  This additional reflector 34 has a reflector reference axis Ax2 that passes through the center position A of the light source 22a and extends forward slightly downward (for example, about 3 ° downward) with respect to the optical axis Ax. The reflecting surface 34a of the additional reflector 34 has a vertical cross-sectional shape that is set to a parabolic shape with the central position A of the light source 22a as a focal point and the reflector reference axis Ax2 as an axis. Precisely, the cross-sectional shape along the plane inclined by the inclination angle of the reflector reference axis Ax2 with respect to the horizontal plane) has the center position A of the light source 22a as the first focal point and the center position A on the reflector reference axis Ax2. Is set to an elliptical shape having a second focal point at a point B that is a predetermined distance away from the front.

  As a result, the additional reflector 34 reflects the light from the light source 22a as parallel light slightly downward with respect to the optical axis Ax in the vertical direction, and is the second focal point B in the horizontal direction. The reflected light is once converged and then diffused in the left-right direction.

  The reflective surface 34a of the additional reflector 34 is top-coated with a paint mixed with a blue dye. Such surface treatment is performed for the following reason.

  That is, since the light source bulb 22 is a discharge bulb and iodide is accumulated in the lower region of the discharge chamber, the downward emitted light from the light source 22a is yellowish. Since the additional reflector 34 is disposed below the light source 22a, yellowish light is incident on the reflecting surface 34a. Therefore, by applying a top coat to the reflecting surface 34a with a paint in which a blue dye having a complementary color with yellow is mixed, the reflected light from the reflecting surface 34a is substantially white light. The light distribution quality is improved.

  FIG. 5 is a perspective view showing a light distribution pattern formed on a virtual vertical screen arranged at a position 25 m ahead of the lamp by light irradiated forward from the vehicle headlamp 10.

  As shown in the figure, this light distribution pattern is a left light distribution low beam light distribution pattern PL, which has a horizontal cut-off line CL1 at its upper edge and a predetermined angle (for example, about 15 °) from the horizontal cut-off line CL1. The elbow point E, which is the intersection of both the cut-off lines CL1, CL2, is located at 0.5 to 0.6 ° of HV, which is the vanishing point in the front direction of the lamp. The position is set to a lower position. In the low beam light distribution pattern PL, a hot zone HZ which is a high luminous intensity region is formed so as to surround the elbow point E.

  The low beam light distribution pattern PL is formed as a combined light distribution pattern of the basic light distribution pattern P0 and the additional light distribution pattern Pa.

  The basic light distribution pattern P0 is a light distribution pattern that forms the basic shape of the low-beam light distribution pattern PL, and is formed by light from the light source 22a that is reflected by the reflector 24 and transmitted through the projection lens 28. Yes. The horizontal and oblique cut-off lines CL1 and CL2 are formed in the basic light distribution pattern P0 as inverted projection images of the upper end edge 32a of the shade 32.

  On the other hand, the additional light distribution pattern Pa is a light distribution pattern formed in addition to the basic light distribution pattern P0 in order to sufficiently secure the brightness of the diffusion region of the low beam light distribution pattern PL. It is formed by reflected light from the additional reflector 34.

  This additional light distribution pattern Pa is formed as a horizontally long light distribution pattern that diffuses to the left and right sides around the VV line, which is a vertical line passing through HV. The upper end edge of the additional light distribution pattern Pa is located slightly below the horizontal cut-off line CL1, but this is because the reflector reference axis Ax2 of the additional reflector 34 is slightly downward with respect to the optical axis Ax. This is because it is set.

  In the additional light distribution pattern Pa, a plurality of curves formed substantially concentrically with the contour curve are isoilluminance curves, and the additional light distribution pattern Pa gradually increases from the outer peripheral edge toward the center thereof. It shows brightening.

  As described in detail above, the vehicle headlamp 10 according to the present embodiment is configured as a projector-type vehicle headlamp that performs light irradiation for forming the low beam light distribution pattern PL. Since the light source bulb 22 is inserted and fixed to the reflector 24 from the side of the optical axis Ax extending in the vehicle front-rear direction, the front-rear length of the lamp can be shortened to make it compact.

  At that time, since the light source bulb 22 is inserted and fixed at a position away from the optical axis Ax, the side area of the optical axis in the reflecting surface 24a of the reflector 24 is effectively used for light distribution control. Can do. Then, a diffusion region of the low beam distribution pattern PL can be formed by the reflected light from the region on the side of the optical axis, and sufficient brightness can be secured in this diffusion region.

  In the vehicle headlamp 10 according to the present embodiment, the additional reflector 34 disposed below the light source 22a is configured to irradiate the light from the light source 22a forward without passing through the projection lens 28. Therefore, the additional light distribution pattern Pa formed by the light irradiation is added to the basic light distribution pattern P0 formed by the light reflected by the reflector 24 and transmitted through the projection lens 28, thereby The brightness of the low beam light distribution pattern PL can be sufficiently secured.

  At this time, since the light source 22a is disposed at a position away from the optical axis Ax, the additional reflector 34 can be disposed close to the light source 22a, and a large solid angle can be secured. As a result, a sufficient light source light flux incident on the additional reflector 34 can be secured, and the additional light distribution pattern Pa can be made sufficiently bright.

As described above, according to the present embodiment, the brightness of the diffusion region of the light distribution pattern can be reduced even if the projector-type vehicle headlamp adopts a side-insertion-type lamp configuration. It can be secured sufficiently.

  In the present embodiment, in order to form a low beam light distribution pattern PL having horizontal and oblique cutoff lines CL1 and CL2 at the upper edge, the shade 32 emits light at the upper edge 32a in the vicinity of the rear focal point F of the projection lens 28. Since it is arranged so as to be positioned in the vicinity of the axis Ax and thereby part of the reflected light from the reflector 24 is shielded, a part of the light source light beam is lost. By adopting the configuration of the embodiment, it is possible to sufficiently ensure the brightness of the low beam light distribution pattern PL by effectively using the remaining light source light flux.

  At this time, since the additional reflector 34 is disposed below the optical axis Ax, the reflected light control by the additional reflector 34 can be easily performed without being hindered by the presence of the shade 32.

  In the present embodiment, since the light source 22a is configured as a line light source extending in the direction of the bulb center axis Ax1 of the light source bulb 22, an image of the light source 22a formed by the reflected light from the additional reflector 34 is entirely displayed. It can be a horizontally long image. Thus, since the vertical width of the additional light distribution pattern Pa can be reduced, it is possible to prevent the short distance area on the road surface ahead of the vehicle from becoming excessively bright.

  In addition, in the present embodiment, the reflection surface 34a of the additional reflector 34 is configured to reflect the light from the light source 22a as parallel light in the vertical direction, so that the vertical width of the additional light distribution pattern Pa is minimized. It can be suppressed and its brightness can be increased.

  Further, in the present embodiment, the reflection surface 34a of the additional reflector 34 is configured to reflect the light from the light source 22a toward the optical axis Ax in the left-right direction, and once converges the reflected light from the additional reflector 34. After that, the light is diffused in the left-right direction, so that it is possible to prevent the reflected light from the additional reflector 34 from being inadvertently shielded by other lamp component members such as the inner panel 16 and the additional light distribution. The pattern Pa can be formed as a horizontally long light distribution pattern.

  Next, a second embodiment of the present invention will be described.

  FIG. 6 is a side sectional view showing the lamp unit 120 of the vehicle headlamp according to the present embodiment as a single item.

  As shown in the figure, the lamp unit 120 is different from the additional reflector 34 in the first embodiment in the configuration of the additional reflector 134, but the other configurations are the same as those of the lamp unit 20 in the first embodiment. It is exactly the same.

  In the additional reflector 134 of the present embodiment, the reflector reference axis Ax3 extends in parallel with the optical axis Ax.

  The reflecting surface 134a of the additional reflector 134 has a vertical cross-sectional shape that is set to a curve having a slightly smaller curvature with respect to a parabola with the center position A of the light source 22a as a focal point and the reflector reference axis Ax3 as an axis. Thus, the light from the light source 22a is reflected slightly downward with respect to the straight line L parallel to the reflector reference axis Ax3. At that time, the downward angle of the reflected light is set to be larger in the upper region than in the lower region of the reflecting surface 134a, and thus the light from each part of the light source 22a does not protrude upward from the straight line L. , As close to the straight line L as possible.

  The horizontal sectional shape of the reflecting surface 134a of the additional reflector 134 is set to be exactly the same as that of the additional reflector 34 of the first embodiment.

  FIG. 7 is a perspective view showing a low beam light distribution pattern PL formed on the virtual vertical screen by light emitted forward from a vehicle headlamp including the lamp unit 120 of the present embodiment. .

  As shown in the figure, the low-beam light distribution pattern PL is formed as a combined light distribution pattern of the basic light distribution pattern P0 and the additional light distribution pattern Pb that are exactly the same as those in the first embodiment.

  The additional light distribution pattern Pb has the same formation position and outer shape as the additional light distribution pattern Pa of the first embodiment, but the luminous intensity distribution is different from that of the additional light distribution pattern Pa.

  That is, the additional light distribution pattern Pb has a luminous intensity distribution in which the brightness gradually increases from the lower end edge to the upper end edge, as shown by the isoilluminance curve, for the following reason. Is.

  That is, on the reflecting surface 134a of the additional reflector 134, the upper region is closer to the light source 22a than the lower region, so that the image of the light source 22a formed by the reflected light from the upper region is relatively large. However, since the reflecting surface 134a is configured so that the upper region reflects light from the light source 22a downward than the lower region, the luminous intensity distribution of the additional light distribution pattern Pb is measured from the lower end edge. The brightness may gradually increase toward the upper edge.

  By forming the additional light distribution pattern Pb as in the present embodiment, it is possible to irradiate the road surface in front of the vehicle substantially uniformly from the short-range area to the long-range area. The visibility of the long-distance area on the road surface ahead of the vehicle can be further enhanced while effectively preventing the light from becoming bright.

  Next, a third embodiment of the present invention will be described.

  FIG. 8 is a plan sectional view showing the lamp unit 220 of the vehicle headlamp according to the present embodiment as a single item.

  As shown in the figure, the lamp unit 220 is different from the additional reflector 134 of the second embodiment in the configuration of the additional reflector 234, but the other configuration is exactly the same as that of the additional reflector 134.

  That is, the additional reflector 234 of the present embodiment is different in the horizontal sectional shape from the case of the additional reflector 134 of the second embodiment.

  Specifically, the horizontal shape of the additional reflector 234 is set to an elliptical shape having the central position A of the light source 22a as the first focal point and the reflector reference axis Ax3 as the long axis, like the additional reflector 134. However, the second focal point of the ellipse is set at a position far ahead of the second focal point in the case of the additional reflector 134.

  As a result, the additional reflector 234 reflects the light from the light source 22a toward the second focal point in the left-right direction, and after converging the reflected light once, diffuses it in the left-right direction. The diffusion angle in the left-right direction is set to a considerably smaller value than that of the additional reflector 134.

  The vertical sectional shape of the reflection surface 234a of the additional reflector 234 is set to be exactly the same as that of the additional reflector 134 of the second embodiment.

  FIG. 9 is a perspective view showing a low beam light distribution pattern PL formed on the virtual vertical screen by light irradiated forward from a vehicle headlamp including the lamp unit 220 of the present embodiment. .

  As shown in the figure, the low-beam light distribution pattern PL is formed as a combined light distribution pattern of the basic light distribution pattern P0 and the additional light distribution pattern Pc exactly the same as those in the second embodiment.

  The additional light distribution pattern Pc has a substantially smaller diffusion angle in the left-right direction than the additional light distribution pattern Pb of the second embodiment, but the vertical luminous intensity distribution is the same as that of the additional light distribution pattern Pb. It is. The additional light distribution pattern Pc is a light distribution pattern that is considerably brighter than the additional light distribution pattern Pb.

  By forming the additional light distribution pattern Pc as in the present embodiment, it is possible to irradiate the road surface in front of the vehicle substantially uniformly from the short-range area to the long-range area. The visibility of the long-distance area on the road surface ahead of the vehicle can be further enhanced while effectively preventing the light from becoming bright. At this time, in this additional light distribution pattern Pc, the visibility on both the left and right sides of the long-distance area is lower than that of the additional light distribution pattern Pb, whereas the visibility of the left and right central part of the long-distance area is It can be improved over Pb.

  Next, a fourth embodiment of the present invention will be described.

  FIG. 10 is a side sectional view showing the lamp unit 320 of the vehicle headlamp according to the present embodiment as a single item.

  As shown in the figure, the lamp unit 320 is different from the additional reflector 34 of the first embodiment in the configuration of the additional reflector 334, but other configurations are the same as those of the lamp unit 20 of the first embodiment. It is exactly the same.

  In the additional reflector 334 of this embodiment, the reflector reference axis Ax4 extends forward with a predetermined angle downward with respect to the optical axis Ax.

  The reflecting surface 334a of the additional reflector 334 has a vertical cross-sectional shape with the center position A of the light source 22a as the first focal point and on the reflector reference axis Ax4 in front of the projection lens and from the lower end edge of the additional reflector 334. The point C located slightly below is set in an elliptical shape with the second focal point.

  As a result, the additional reflector 334 reflects the light from the light source 22a toward the point C, which is the second focal point, in the vertical direction, and once converges the reflected light so as to diffuse in the vertical direction. It has become. At this time, since the point C as the second focal point is located slightly below the lower end edge of the additional reflector 334, the light from each part of the light source 22a does not protrude upward from the straight line L parallel to the optical axis Ax. Spreads up and down in the range.

  The horizontal cross-sectional shape of the reflecting surface 334a of the additional reflector 334 is set to be exactly the same as that of the additional reflector 34 of the first embodiment.

  FIG. 11 is a perspective view showing a low beam light distribution pattern PL formed on the virtual vertical screen by light emitted forward from a vehicle headlamp including the lamp unit 320 of the present embodiment. .

  As shown in the figure, the low-beam light distribution pattern PL is formed as a combined light distribution pattern of the basic light distribution pattern P0 and the additional light distribution pattern Pd that are exactly the same as those in the first embodiment.

  The additional light distribution pattern Pd is also a horizontally long light distribution pattern that diffuses to the left and right sides around the VV line, and the diffusion angle in the left-right direction is the same as the additional light distribution pattern Pa of the first embodiment. However, the vertical diffusion angle and luminous intensity distribution are different from those of the additional light distribution pattern Pa.

  That is, the additional light distribution pattern Pd has an upper edge located slightly below the horizontal cut-off line CL1 in the same manner as the additional light distribution pattern Pa, but is lower than the additional light distribution pattern Pa. The diffusion angle in the direction is large, and as indicated by an isoillumination curve, the light intensity distribution has a brightness that gradually increases from the lower end edge toward the upper end edge. This is because the vertical sectional shape of the reflection surface 334a of the additional reflector 334 is set to be elliptical, and the upper region reflects light from the light source 22a downward than the lower region of the reflection surface 334a. It is because it has been.

  By forming the additional light distribution pattern Pd as in the present embodiment, it is possible to irradiate the vehicle front road surface in a wide and substantially uniform manner in the front-rear direction from the short distance region to the long distance region. The visibility of the long-distance area on the road surface ahead of the vehicle can be further enhanced while effectively preventing the area from becoming excessively bright.

  In each of the above embodiments, the light source bulb 22 is described as a discharge bulb. However, a halogen bulb or the like can be used instead. When a halogen bulb is used, iodide does not accumulate in the lower region of the discharge chamber, so that it is possible to eliminate the need for top coating on the reflecting surface 34a of the additional reflector 34.

  Further, in each of the above embodiments, the light source bulb 22 is described as being inserted from the direction just beside the reflector 24. However, even if the insertion angle is slightly deviated from the direction beside this, If the displacement in the direction or the front-rear direction is about 30 ° or less, substantially the same effect as the above embodiment can be obtained.

Side sectional view which shows the vehicle headlamp which concerns on 1st Embodiment of this invention. The side view which shows the lamp unit of the said vehicle headlamp with the single item, Comprising: The figure which shows the optical path of the light reflected with the reflector and the additional reflector It is a plane sectional view showing the above-mentioned lamp unit by a single item, and is a diagram showing an optical path of light reflected by a reflector It is a plane sectional view showing the above-mentioned lamp unit by a single item, and is a diagram showing an optical path of light reflected by an additional reflector The figure which shows transparently the light distribution pattern formed on the virtual vertical screen arrange | positioned in the position of the lamp front 25m with the light irradiated ahead from the said vehicle headlamp The figure similar to FIG. 2 which shows the lamp unit of the vehicle headlamp which concerns on 2nd Embodiment of this invention by a single item. The figure which shows transparently the light distribution pattern formed on the said virtual vertical screen by the light irradiated ahead from the vehicle headlamp which concerns on the said 2nd Embodiment. The figure similar to FIG. 4 which shows the lamp unit of the vehicle headlamp which concerns on 3rd Embodiment of this invention by a single item. The figure which shows transparently the light distribution pattern formed on the said virtual vertical screen by the light irradiated ahead from the vehicle headlamp which concerns on the said 3rd Embodiment. The figure similar to FIG. 2 which shows the lamp unit of the vehicle headlamp which concerns on 4th Embodiment of this invention by a single item. The figure which shows perspectively the light distribution pattern formed on the said virtual vertical screen from the light irradiated ahead from the vehicle headlamp which concerns on the said 4th Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Vehicle headlamp 12 Lamp body 14 Translucent cover 20, 120, 220, 320 Lamp unit 22 Light source bulb 22a Light source 24 Reflector 24a, 34a, 134a, 234a, 334a Reflecting surface 24b Valve insertion fixing part 24c Valve insertion hole 24d Aiming bracket 24e Bottom wall 26 Holder 28 Projection lens 32 Shade 32a Upper edge 34, 134, 234, 334 Additional reflector 50 Aiming mechanism A Center position Ax Optical axis Ax1 Valve central axis Ax2, Ax3, Ax4 Reflector reference axis B, C Point CL1 Horizontal cut-off line CL2 Oblique cut-off line E Elbow point F Rear focus HZ Hot zone L Straight line PL Low beam light distribution pattern P0 Basic light distribution pattern Pa, Pb, Pc, Pd Additional light distribution pattern

Claims (4)

A projection lens disposed on the optical axis extending in the vehicle front-rear direction, a light source disposed rearward of the rear focal point of the projection lens, and light from this light source is reflected toward the optical axis toward the front. A vehicle headlamp comprising a reflector to be
The light source is composed of a light emitting part of a light source bulb inserted and fixed to the reflector from the side of the optical axis at a position spaced downward from the optical axis,
An additional reflector that reflects light from the light source forward without passing through the projection lens is disposed below the light source ,
The reflection surface of the additional reflector is configured such that the upper region reflects light from the light source downward than the lower region of the reflection surface,
The vertical sectional shape of the reflection surface of the additional reflector is a substantially elliptical shape having the position of the light source as the first focal point and the position below the lower edge of the additional reflector in front of the projection lens as the second focal point. is set, car dual headlamp you wherein a.   A shade for shielding part of the reflected light from the reflector is disposed in the vicinity of the rear focal point so that the upper edge of the shade is positioned in the vicinity of the optical axis. The vehicle headlamp according to claim 1.   The vehicle headlamp according to claim 1, wherein the light source is configured as a line light source extending in a direction of a central axis of the light source bulb. The vehicular headlamp according to any one of claims 1 to 3 , wherein the reflection surface of the additional reflector is configured to reflect light from the light source toward the optical axis in the left-right direction. .

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