JP2010033740A - Vehicle headlight - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively prevent light distribution unevenness caused on a road surface in front of a vehicle, even when a filament support for supporting filament extending almost coaxially with an optical axis of a vehicle headlight is almost directly above the optical axis, in a projector type vehicle headlight. <P>SOLUTION: The vertical cross-sectional shape of an upper reflecting region 14aU in a reflecting surface 14a of a reflector 14 is composed of an S-shaped curve having an inflection point Pi, and a comparatively far area on the road surface in front of the vehicle is irradiated with reflected light from a rear reflecting region 14aU1. Consequently, the shadow of the filament support 12b formed in the rear reflecting region 14aU1 is hardly formed as a streaked dark part extending in a longitudinal direction on the road surface in front of the vehicle. At the same time, a comparatively short distance area on the road surface in front of the vehicle is irradiated with reflected light from a front reflecting region 14aU2 located considerably far from the filament support 12b whose shadow is not clearly formed, thus attaining uniform irradiation of the road surface in front of the vehicle. <P>COPYRIGHT: (C)2010,JPO&INPIT

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.

  At this time, as described in, for example, “Patent Document 1”, when the light source is a light emitting portion of a discharge bulb, the discharge bulb generally has an electrode support that is substantially directly below the optical axis. It is used in a state where it is arranged so as to extend substantially parallel to the axis.

JP 2006-79984 A

  However, when the light source is a filament of a halogen bulb, depending on the type of halogen bulb, the filament extends substantially coaxially with the optical axis, and the filament support that supports the filament is located directly above the optical axis. Some are used in a state of being arranged so as to extend substantially parallel to the optical axis.

  A projector-type vehicle headlamp incorporating such a type of halogen bulb has the following problems.

  That is, the light distribution pattern formed by the light emitted from the projector-type vehicle headlamp is a reverse projection of the light source image formed on the rear focal plane of the projection lens by the light from the light source reflected by the reflector. In this case, a reverse projection image of the light source image formed by the reflected light from the reflection region almost directly above the optical axis on the reflecting surface of the reflector is a filament in which the light source extends substantially coaxially with the optical axis. Therefore, the image is a vertically long image on the virtual vertical screen arranged in front of the lamp, and the image extends in the front-rear direction on the road surface in front of the vehicle.

  Therefore, if a filament support extending substantially parallel to the optical axis is arranged almost directly above the optical axis, light emitted from the filament in a direction substantially directly above is shielded by the filament support. The light from the filament does not enter the reflection area on the reflection surface almost directly above the optical axis. And the shadow of the filament support formed in the reflective region almost directly above the optical axis is formed as a streak-like dark portion extending in the front-rear direction on the road surface in front of the vehicle, which causes a large amount of uneven light distribution. There is a problem.

  The present invention has been made in view of such circumstances. In a projector-type vehicle headlamp, a filament support that supports a filament that extends substantially coaxially with the optical axis thereof is substantially above the optical axis. The purpose of the present invention is to provide a vehicular headlamp that can effectively suppress uneven light distribution that occurs on the road surface in front of the vehicle even when it extends substantially parallel to the optical axis.

  In the present invention, the above-mentioned object is achieved by devising the reflecting surface of the 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 behind the rear focal point of the projection lens, and light from the 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 filament extending substantially coaxially with the optical axis;
The filament is configured as a part of a halogen bulb provided with a filament support that extends substantially parallel to the optical axis substantially above the optical axis.
The cross-sectional shape along the vertical plane parallel to the optical axis of the upper reflective region located above the optical axis on the reflective surface of the reflector is composed of an S-shaped curve having an inflection point. It is characterized by this.

  The vehicle headlamp according to the present invention may have a configuration including a shade for shielding a part of the reflected light from the reflector, or a configuration not including the shade.

  The above “S-curve” means that the portion on the rear side of the inflection point is configured by a concave curve and the portion on the front side of the inflection point is configured by a convex curve. In this case, the curvature of the concave curve and the curvature of the convex curve are not particularly limited.

  As shown in the above configuration, the vehicular headlamp according to the present invention is a projector-type vehicular headlamp, and the light source is configured by a filament extending substantially coaxially with the optical axis, and This filament is configured as a part of a halogen bulb provided with a filament support extending substantially parallel to the optical axis substantially directly above the optical axis, and the reflective surface of the reflector is the optical axis of the upper reflective region. Since the cross-sectional shape along the vertical plane parallel to the head is composed of an S-shaped curve having an inflection point, the following operational effects can be obtained.

  That is, in the vehicle headlamp according to the present invention, the light emitted from the filament in a direction almost directly above is shielded by the filament support, so that the reflection is almost directly above the optical axis in the upper reflection region of the reflector. The light from the filament will not enter the region.

  At that time, in the rear reflection region near the rear end in the upper reflection region of the reflector, the shadow of the filament support is clearly formed because the rear reflection region and the filament support are relatively close to each other. In the front reflection region near the front end in the upper reflection region, the front reflection region and the filament support are relatively separated from each other, so that the shadow of the filament support is not clearly formed.

  In this regard, the reflector of the vehicle headlamp according to the present invention has a cross-sectional shape along a vertical plane parallel to the optical axis of the upper reflection region, which is composed of an S-shaped curve having an inflection point. The rear reflection region is constituted by a reflection region having a concave curved cross-sectional shape behind the inflection point. At this time, if the surface shape of the rear reflection area is adjusted appropriately so that the reflected light from the rear reflection area passes through the rear focal plane of the projection lens in the vicinity of the upper part of the optical axis, this reflected light Can be light that irradiates a relatively far region on the road surface in front of the vehicle. And it can suppress effectively that the shadow of the filament support formed in this rear part reflection area | region will be formed as a stripe-shaped dark part extended in the front-back direction in the vehicle front road surface.

  On the other hand, the front reflection region near the front end in the upper reflection region of the reflector is constituted by a reflection region having a cross-sectional shape of a convex curve ahead of the inflection point. Therefore, the reflected light from the front reflection region can be passed through the rear focal plane of the projection lens substantially above the optical axis. For this reason, the reflected light from the front reflection area can be used as light that irradiates a relatively short distance area on the road surface in front of the vehicle. At this time, since the front reflection region is located far from the filament support as compared with the rear reflection region, the shadow of the filament support is not clearly formed in the front reflection region. . Therefore, even if a relatively short distance region on the road surface in front of the vehicle is irradiated by the reflected light from the front reflection region, a streak-like dark portion extending in the front-rear direction is not formed on the road surface in front of the vehicle. can do.

  As described above, according to the present invention, in the projector-type vehicle headlamp, the filament support that supports the filament extending substantially coaxially with the optical axis extends substantially parallel to the optical axis substantially above the optical axis. Even in this case, uneven light distribution that occurs on the road surface ahead of the vehicle can be effectively suppressed.

  Moreover, like the vehicle headlamp according to the present invention, the reflector is configured by forming a cross-sectional shape along a vertical plane parallel to the optical axis of the upper reflection area of the reflector with an S-shaped curve having an inflection point. More reflected light can be made incident on the projection lens.

  In the above configuration, it is necessary to irradiate a relatively short distance area on the road surface ahead of the vehicle if the position of the inflection point is gradually displaced forward from right above the optical axis toward both left and right sides. It is possible to prevent the above light from being used. Thereby, the road surface in front of the vehicle can be irradiated substantially uniformly.

  At this time, if the upper reflection area of the reflector is formed so that light from the filament reflected at the position of the inflection point in the upper reflection area is made incident near the outer periphery of the projection lens, the upper reflection area The reflected light from the area is utilized to the maximum, and the position where the reflected light from the rear reflection area passes through the rear focal plane of the projection lens is kept at a low position. It can be the light that illuminates the far field.

  At this time, the rear reflection area in the upper reflection area of the reflector emits light from the filament reflected by the rear reflection area and transmitted through the projection lens in a direction within 10 ° downward with respect to the optical axis. With the configuration formed in the above, it is possible to more reliably suppress the shadow of the filament support formed in the rear reflection region from being formed as a streaky dark portion extending in the front-rear direction on the vehicle front road surface. it can.

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

  FIG. 1 is a side sectional view showing a vehicle headlamp 10 according to an embodiment of the present invention.

  As shown in the figure, the vehicle headlamp 10 according to the present embodiment is configured as a projector-type lamp unit that performs light irradiation for forming a low-beam light distribution pattern. It is designed to be used in the state of being incorporated in

  The vehicle headlamp 10 includes a halogen bulb 12, a reflector 14, a projection lens 16, a shade 18, and a holder 20, and has an optical axis Ax that extends in the vehicle front-rear direction. However, the vehicle headlamp 10 is arranged in a state in which the optical axis Ax extends in a downward direction by about 0.5 to 0.6 ° with respect to the vehicle front-rear direction when the aiming adjustment is completed. It is like that.

  The projection lens 16 is a plano-convex aspheric lens having a convex front surface and a flat rear surface, and is disposed on the optical axis Ax. The projection lens 16 projects the light source image formed on the rear focal plane (that is, the focal plane including the rear focal point F) as an inverted image on the vertical virtual screen arranged in front of the lamp. It has become.

  The halogen bulb 12 uses a filament 12 a extending substantially coaxially with the optical axis Ax as a light source, and is inserted into the rear top opening 14 b of the reflector 14. The halogen bulb 12 is configured as a so-called H11 type halogen bulb provided with a filament support 12b extending substantially parallel to the optical axis Ax substantially above the optical axis Ax.

  FIG. 2 is a front view showing the reflector 14 together with the halogen bulb 12.

  As shown in the figure, the reflector 14 has a reflecting surface 14a that reflects light from the halogen bulb 12 forward and toward the optical axis Ax. The cross-sectional shape along the plane including the optical axis Ax of the reflecting surface 14a is set to be substantially elliptical, and the eccentricity is set to gradually increase from the vertical cross section toward the horizontal cross section. As a result, the light from the filament 12a reflected by the reflecting surface 14a is substantially converged to the vicinity of the rear focal point F in the vertical section, and the convergence position is set to the front side of the rear focal point F in the horizontal section. It is supposed to be displaced. A specific configuration of the reflecting surface 14a will be described in detail later.

  The holder 20 is a cylindrical member disposed between the projection lens 16 and the reflector 14. The holder 20 fixes and supports the projection lens 16 at the front end portion thereof, and is fixedly supported by the reflector 14 at the rear end portion thereof. .

  The shade 18 is formed integrally with the holder 20 so as to extend rearward from the front end portion in a substantially lower half portion inside the holder 20. The shade 18 is formed such that an upper end edge 18a thereof passes through the rear focal point F of the projection lens 16, thereby blocking part of the reflected light from the reflection surface 14a of the reflector 14 and thereby projecting the projection lens 16. Most of the upward light emitted forward from is removed. At this time, the upper end edge 18a of the shade 18 extends in a substantially arc shape in the horizontal direction along the rear focal plane of the projection lens 16 and is formed in a step difference.

  The lower reflection region 14aL located below the optical axis Ax on the reflection surface 14a of the reflector 14 causes the light from the filament 12a to be slightly larger toward the optical axis Ax than the upper reflection region 14aU located above the optical axis Ax. It is configured to deflect and reflect, so that the reflected light from the reflecting surface 14a is not blocked by the shade 18 more than necessary.

  On the other hand, the upper reflection region 14aU located above the optical axis Ax on the reflection surface 14a is configured by an S-shaped curve having a cross-sectional shape along a vertical plane parallel to the optical axis Ax and having an inflection point Pi. Yes. In the S-shaped curve, a portion on the rear side from the inflection point Pi is configured by a concave curve, and a portion on the front side from the inflection point Pi is configured by a convex curve.

  This inflection point Pi is set in a direction that is inclined upward by about 60 to 70 ° with respect to the optical axis Ax from the light emission center of the filament 12a to the front immediately above the optical axis Ax. The position of the inflection point Pi is gradually displaced forward from right above the optical axis Ax toward both the left and right sides. At that time, the left and right end points of the curve C connecting the inflection points Pi reach the front end edge of the reflecting surface 14a at a position slightly above the horizontal plane including the optical axis Ax.

  The upper reflection region 14aU of the reflection surface 14a is incident on the vicinity of the outer peripheral edge of the projection lens 12 with the light from the filament 12a reflected at the position of the inflection point Pi (that is, the point on the curve C) in the upper reflection region 14aU. It is formed to let you.

  The rear reflection area 14aU1 located behind the curve C in the upper reflection area 14aU is directed downward with respect to the optical axis Ax by the light from the filament 12a reflected by the rear reflection area 14aU1 and transmitted through the projection lens 12. It is formed to emit in a direction within 10 °. In order to realize this, the rear reflection region 14aU1 is formed so that light from the emission center of the filament 12a is emitted from the projection lens 12 in a direction within about 6 ° downward with respect to the optical axis Ax.

  On the other hand, the front reflection region 14aU2 located on the front side of the curve C in the upper reflection region 14aU has a cross-sectional shape along a vertical plane parallel to the optical axis Ax, which is a convex curve. At this time, the light from the filament 12a reflected by the front reflection region 14aU2 and transmitted through the projection lens 12 is emitted so as to be emitted further downward than 10 ° downward with respect to the optical axis Ax.

  In FIG. 1, an upper reflection region 14aU ′ whose cross-sectional shape is indicated by a two-dot chain line is an upper reflection region of a reflector in a general projector-type lamp unit. Compared to the upper reflection region 14aU ′, the rear reflection region 14aU1 in the upper reflection region 14aU of the present embodiment is configured to largely deflect and reflect the light from the filament 12a toward the optical axis Ax, The front reflection region 14aU2 in the upper reflection region 14aU of the present embodiment is formed so as to deflect and reflect light from the filament 12a small toward the optical axis Ax.

  FIG. 3 is a perspective view of a low beam light distribution pattern PL formed on a virtual vertical screen disposed at a position 25 m ahead of the lamp by light irradiated forward from the vehicle headlamp 10 according to the present embodiment. FIG.

  This low beam light distribution pattern PL is a left light distribution pattern for low beam, and has upper and lower cut-off lines CL1 and CL2 at its upper edge. The cut-off lines CL1 and CL2 extend in the horizontal direction at the left and right steps with the VV line passing through the HV, which is a vanishing point in the front direction of the lamp, in the vertical direction, and are on the right side of the VV line. The opposite lane side portion is formed as a lower cut-off line CL1, and the own lane side portion on the left side of the VV line is formed as an upper cut-off line CL2 that rises from the lower cut-off line CL1 through an inclined portion. Is formed.

  In this low beam distribution pattern PL, the elbow point E, which is the intersection of the lower cut-off line CL1 and the VV line, is located about 0.5 to 0.6 ° below HV. This is because the optical axis Ax extends in a downward direction by about 0.5 to 0.6 ° with respect to the vehicle longitudinal direction. 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.

  This low beam light distribution pattern PL is formed as a reverse projection image of the light source image formed on the rear focal plane of the projection lens 16 by the light from the filament 12a reflected by the reflector 14. The cut-off lines CL1 and CL2 are formed as reverse projection images of the upper edge 18a of the shade 18.

  The low beam light distribution pattern PL is formed as a combined light distribution pattern in which two light distribution patterns PA and PB are superimposed.

  The light distribution pattern PA is a light distribution pattern formed by light from the filament 12a reflected by the rear reflection region 14aU1 and the lower reflection region 14aL of the upper reflection region 14aU on the reflection surface 14a of the reflector 14, and is a low beam light distribution pattern. It forms the main part of the pattern PL.

  On the other hand, the light distribution pattern PB is a light distribution pattern formed by light from the filament 12a reflected by the front reflection region 14aU2 of the upper reflection region 14aU on the reflection surface 14a of the reflector 14, and below the light distribution pattern PA. A horizontally elongated light distribution pattern is formed on the side so as to partially overlap the lower edge of the light distribution pattern PA.

  In the figure, a light distribution pattern PL ′ indicated by a two-dot chain line is formed by light from a filament 12a reflected by a general reflector having an upper reflection region 14aU ′ having a cross-sectional shape indicated by a two-dot chain line in FIG. It is a light distribution pattern for low beams.

  In the low beam light distribution pattern PL ′ indicated by the two-dot chain line, a concave portion PLa ′ that is largely bound upward is formed in the vicinity of the VV line at the lower edge. Such a concave portion PLa ′ is formed because light emitted from the filament 12a in a direction almost directly above is shielded by the filament support 12b, and reflected almost directly above the optical axis Ax in the upper reflection region 14aU ′. This is because light from the filament 12a does not enter the region A (region indicated by the mesh line in FIG. 2) A. And this recessed part PLa 'will be formed in the vehicle front road surface as a stripe-like dark part extended toward a front from a comparatively short distance area | region.

  The light distribution pattern PA of the low beam light distribution pattern PL in the present embodiment is narrower in the vertical width near the cut-off lines CL1 and CL2 as a whole than the low beam light distribution pattern PL ′. This is because, in FIG. 1, the rear reflection area 14aU1 of the upper reflection area 14aU largely deflects and reflects light from the filament 12a closer to the optical axis Ax than the upper reflection area 14aU ′ whose cross-sectional shape is indicated by a two-dot chain line. It is because it is constituted so that the

  At this time, the light distribution pattern PA is formed such that the lower end edge thereof is positioned above the horizontal line at a position of 10 ° downward with respect to the elbow point E. In FIG. 1, the rear reflection area 14aU1 emits light from the filament 12a reflected by the rear reflection area 14aU1 and transmitted through the projection lens 12 in a direction within 10 ° downward with respect to the optical axis Ax. It is because it is formed.

  Also in the light distribution pattern PA, a concave portion PAa that is constricted upward is formed in the vicinity of the VV line at the lower edge of the light distribution pattern PA. However, the degree of constriction of the concave portion PAa is smaller than that of the concave portion PLa ′ of the light distribution pattern PL ′ for low beam, and the constricted position is displaced higher than that of the concave portion PLa ′. Regarding the reflected light from the reflection area A substantially above the optical axis Ax, the rear reflection area 14aU1 of the upper reflection area 14aU is compared with the upper reflection area 14aU ′ whose sectional shape is indicated by a two-dot chain line. This is because it is closer to the optical axis Ax. Accordingly, the concave portion PAa of the light distribution pattern PA is displaced forward on the road surface in front of the vehicle from the concave portion PLa ′ of the low beam light distribution pattern PL ′, and the depth in the front-rear direction is shallow. Therefore, it becomes inconspicuous as a streaky dark part.

  On the other hand, in the light distribution pattern PB of the low beam light distribution pattern PL in the present embodiment, a concave portion PBa that is slightly constricted upward is formed in the vicinity of the VV line at the lower end edge. There is almost no depth in the direction, and there is no streak-like dark part.

  Since this light distribution pattern PB is formed on the lower side of the light distribution pattern PA so as to partially overlap the lower end edge of the light distribution pattern PA, the concave portion PAa of the light distribution pattern PA has a stripe shape. It is prevented that it becomes a dark part, and the comparatively short distance area | region in a vehicle front road surface will be irradiated sufficiently brightly.

  Therefore, the low beam light distribution pattern PL formed as a combined light distribution pattern of these two light distribution patterns PA and PB irradiates the road surface in front of the vehicle substantially uniformly from the short distance area to the far area.

  As described above in detail, the vehicular headlamp 10 according to the present embodiment is a projector-type vehicular headlamp, and its light source is configured by a filament 12a extending substantially coaxially with the optical axis Ax. The filament 12a is configured as a part of the halogen bulb 12 having a filament support 12b extending substantially parallel to the optical axis Ax substantially directly above the optical axis Ax. Since the cross-sectional shape of the surface 14a along the vertical plane parallel to the optical axis Ax of the upper reflective region 14aU is configured by an S-shaped curve having an inflection point Pi, the following effects are obtained. be able to.

  That is, in the vehicle headlamp 10 according to the present embodiment, the light emitted from the filament 12a of the halogen bulb 12 in the substantially upper direction is shielded by the filament support 12b. The light from the filament 12a does not enter the reflection region A substantially above the optical axis Ax at 14aU.

  At that time, in the rear reflection area 14aU1 near the rear end in the upper reflection area 14aU of the reflector 14, the shadow of the filament support 12b is clearly formed because the rear reflection area 14aU1 and the filament support 12b are relatively close to each other. However, since the front reflection area 14aU2 near the front end of the reflection surface 14a is relatively separated from the front support area 14aU2 and the filament support 12b, the shadow of the filament support 12b is clearly formed. There is no end to it.

  In this regard, the reflector 14 of the vehicle headlamp 10 according to the present embodiment has an S shape in which the cross-sectional shape of the upper reflection region 14aU along the vertical plane parallel to the optical axis Ax has an inflection point Pi. Since it is constituted by a curve, the rear reflection area 14aU1 in the upper reflection area 14aU is constituted by a reflection area having a cross-sectional shape of a concave curve behind the inflection point Pi. At this time, the rear reflection area 14aU1 is formed so as to pass the reflected light from the rear reflection area 14aU1 through the rear focal plane of the projection lens 16 in the vicinity of the upper portion of the optical axis Ax. Can be light that irradiates a relatively far region on the road surface in front of the vehicle. As a result, the shadow of the filament support 12b formed in the rear reflection region 14aU1 can be effectively suppressed from being formed as a streak-like dark portion extending in the front-rear direction on the vehicle front road surface.

  On the other hand, the front reflection region 14aU2 in the upper reflection region 14aU of the reflector 14 is constituted by a reflection region having a convex curved cross-sectional shape in front of the inflection point Pi. Therefore, the reflected light from the front reflection region 14aU2 can pass through the rear focal plane of the projection lens 16 substantially above the optical axis Ax. For this reason, the reflected light from the front reflection area 14aU2 can be used as light for irradiating a relatively short distance area on the road surface in front of the vehicle. At this time, since the front reflection area 14aU2 is located far from the filament support 12b as compared with the rear reflection area 14aU1, the shadow of the filament support 12b is clearly formed in the front reflection area 14aU2. There is no end to it. Therefore, even if a relatively short distance area on the road surface in front of the vehicle is irradiated by the reflected light from the front reflection area 14aU2, a streak-like dark portion extending in the front-rear direction is not formed on the road surface in front of the vehicle. Can be.

  And by unevenly irradiating the reflected light from the rear reflection area 14aU1 and the front reflection area 14aU2 in the upper reflection area 14aU, it is possible to effectively suppress uneven light distribution that occurs on the road surface in front of the vehicle.

  As described above, in the projector-type vehicle headlamp 10 according to the present embodiment, the filament support 12b that supports the filament 12a extending substantially coaxially with the optical axis Ax has the optical axis substantially above the optical axis Ax. Despite extending substantially parallel to Ax, uneven light distribution that occurs on the road surface ahead of the vehicle can be effectively suppressed.

  Further, the vehicle headlamp 10 according to the present embodiment is an S-shaped curve in which the cross-sectional shape of the upper reflection region 14aU of the reflector 14 along the vertical plane parallel to the optical axis Ax has an inflection point Pi. Since it is configured, more reflected light from the reflector 14 can be incident on the projection lens 16.

  Furthermore, in the vehicle headlamp 10 according to the present embodiment, the position of the inflection point Pi is gradually displaced forward from the position directly above the optical axis Ax toward the left and right sides. In order to irradiate a relatively short distance area, it is possible to prevent unnecessary light from being used. Thereby, the road surface in front of the vehicle can be irradiated substantially uniformly.

  At this time, the upper reflection region 14aU of the reflector 14 is formed so that light from the filament 12a reflected at the position of the inflection point Pi in the upper reflection region 14aU is incident on the vicinity of the outer peripheral edge of the projection lens 16. Therefore, after making the maximum use of the reflected light from the upper reflective area 14aU, the position where the reflected light from the rear reflective area 14aU1 passes through the rear focal plane of the projection lens 16 is suppressed to a low position. Can be used to irradiate a relatively far region on the road surface in front of the vehicle.

  At that time, the rear reflection area 14aU1 emits light from the filament 12a reflected by the rear reflection area 14aU1 and transmitted through the projection lens 16 in a direction within 10 ° downward with respect to the optical axis Ax. Thus, the shadow of the filament support 12b formed in the rear reflection region 14aU1 can be more reliably suppressed from forming as a streak-like dark portion extending in the front-rear direction on the vehicle front road surface. .

  In the above embodiment, the vehicular headlamp 10 has been described as being configured as a projector-type lamp unit that performs light irradiation for forming a low beam light distribution pattern. It is also possible to remove the shade 18 from the configuration 10 and configure a projector-type lamp unit that performs light irradiation for forming a high-beam light distribution pattern. Even in the case of such a configuration, it is possible to effectively suppress uneven light distribution that occurs on the road surface in front of the vehicle.

  In addition, the numerical value shown as a specification in the said embodiment is only an example, and of course, you may set these to a different value suitably.

Side sectional view which shows the vehicle headlamp which concerns on one Embodiment of this invention The front view which shows the reflector of the said vehicle headlamp with a halogen bulb The figure which shows perspectively the light distribution pattern for low beams formed on the virtual vertical screen arrange | positioned in the position of 25 m ahead of a lamp | ramp by the light irradiated ahead from the said vehicle headlamp.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Vehicle headlamp 12 Halogen bulb 12a Filament 12b Filament support 14 Reflector 14a Reflection surface 14aL Lower reflection area 14aU, 14aU 'Upper reflection area 14aU1 Rear reflection area 14aU2 Front reflection area 14b Rear opening 16 Projection lens 18 Shade 18a Upper edge 20 Holder A Reflection area Ax Optical axis C Curve CL1, CL2 Cut-off line E Elbow point F Rear focus HZ Hot zone PA, PB Additional light distribution pattern PAa, PBa, PLa 'Recessed part PL, PL' Light distribution pattern for low beam Pi inflection point

Claims (4)

A projection lens disposed on the optical axis extending in the vehicle front-rear direction, a light source disposed behind the rear focal point of the projection lens, and light from the 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 filament extending substantially coaxially with the optical axis;
The filament is configured as a part of a halogen bulb provided with a filament support that extends substantially parallel to the optical axis substantially above the optical axis.
The cross-sectional shape along the vertical plane parallel to the optical axis of the upper reflective region located above the optical axis on the reflective surface of the reflector is composed of an S-shaped curve having an inflection point. A vehicle headlamp characterized by that.   The vehicular headlamp according to claim 1, wherein the position of the inflection point is gradually displaced forward from right above the optical axis toward both left and right sides.   The upper reflection region is formed so that light from the filament reflected at the position of the inflection point in the upper reflection region is incident on the vicinity of the outer peripheral edge of the projection lens. Item 3. A vehicle headlamp according to Item 2.   The rear reflection area located behind the curve connecting the inflection points in the upper reflection area reflects light from the filament reflected by the rear reflection area and transmitted through the projection lens to the optical axis. 4. The vehicular headlamp according to claim 2, wherein the vehicular headlamp is formed so as to emit light in a downward direction within 10 [deg.].

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