JP4531673B2 - Vehicle headlamp - Google Patents

Description

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

  In general, a projector-type vehicle headlamp includes a projection lens disposed on an optical axis extending in the vehicle front-rear direction, a light source disposed behind the rear focal point of the projection lens, and a light source from the light source. It is configured to include a reflector that reflects light toward the optical axis toward the front, and a predetermined lamp light distribution pattern is formed by the light from the light source reflected by the reflector and transmitted through the projection lens. It has become.

  In this case, in “Patent Document 1”, in such a projector-type vehicle headlamp, the surface shape of the lens peripheral portion of the projection lens is gradually changed, and the position of the rear focal point is determined as the rear focal point of the projection lens. It is described that it is displaced from the rear to the rear.

JP-A-6-84401

  In a conventional projector-type vehicle headlamp, a light source image formed on the rear focal plane of the projection lens is projected and irradiated as it is by the projection lens. There is a problem that the central luminous intensity of the pattern cannot be sufficiently increased, and the uneven light distribution cannot be sufficiently suppressed.

  If the projector-type vehicle headlamp described in the above-mentioned “Patent Document 1” is adopted, the color stripes caused by the chromatic aberration of the projection lens are made inconspicuous on the lamp light distribution pattern. However, it is impossible to suppress uneven light distribution of the lamp light distribution pattern or increase the central luminous intensity.

  The present invention has been made in view of such circumstances, and in a projector-type vehicle headlamp, the center luminous intensity of a lamp light distribution pattern formed by the vehicle headlamp is sufficiently increased. An object of the present invention is to provide a vehicular headlamp that can reduce the unevenness of light distribution.

  The present invention is intended to achieve the above object by devising the configuration of the projection lens.

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 configured to form a predetermined lamp light distribution pattern by the light from the light source reflected by the reflector and transmitted through the projection lens.
The projection lens is composed of a lens central part located in the vicinity of the optical axis, and a lens peripheral part surrounding the lens central part,
The rear focal point in the horizontal cross section of the central portion of the lens is set at a position displaced in the front-rear direction from the rear focal point of the projection lens, and the reflected light from the reflector is at least horizontally transmitted by the central portion of the lens. The diffused region of the lamp light distribution pattern is diffused to form a high luminous intensity region of the lamp light distribution pattern by making the reflected light from the reflector substantially parallel light by the lens periphery. It is characterized by that.

  The above-mentioned “predetermined lamp light distribution pattern” is not limited to a specific light distribution pattern. For example, the light distribution pattern for high beam, the light distribution pattern for low beam, or a part of these light distribution patterns A light distribution pattern or the like can be adopted.

  The type of the “light source” is not particularly limited, and for example, a discharge light emitting part of a discharge bulb, a filament of a halogen bulb, or the like can be employed. Further, the specific position and orientation of the “light source” are not particularly limited as long as the “light source” is arranged on the rear side of the rear focal point of the projection lens. It may be arranged on the axis or may be arranged at a position off the optical axis.

  Specific configurations such as the size and outer shape of the “lens central portion” are not particularly limited. In addition, this “lens central portion” is set at a position where the rear focal point in the horizontal section is displaced in the front-rear direction from the rear focal point of the projection lens. The displacement direction is the front of the rear focal point. The side may be sufficient and the back side may be sufficient. On the other hand, the rear focal point in the vertical cross section of the “lens center” may be set at the rear focal point of the projection lens, or set at a position displaced in the front-rear direction from the rear focal point. May be.

  As shown in the above configuration, the vehicular headlamp according to the present invention is configured as a projector-type vehicular headlamp, and is reflected by the light from the light source reflected by the reflector and transmitted through the projection lens. The projection lens is composed of a lens central part located in the vicinity of the optical axis and a lens peripheral part surrounding the lens central part. The rear focal point in the horizontal section is set at a position displaced in the front-rear direction from the rear focal point of the projection lens, and the central portion of the lens diffuses the reflected light from the reflector at least in the horizontal direction. A diffusion region of the light distribution pattern is formed, and a high luminous intensity region of the lamp light distribution pattern is formed by making the reflected light from the reflector substantially parallel light by the peripheral portion of the lens. Since going on, it is possible to obtain the following effects.

  That is, in the projector-type vehicle headlamp, the reflected light from the reflector is reflected on the reflecting surface from the central reflection area located relatively close to the light source, and is incident on the center of the projection lens. Reflected light from the peripheral reflection region located relatively far from the lens enters the lens peripheral portion of the projection lens. At that time, the light source image formed on the rear focal plane of the projection lens by the reflected light from the central reflection area is relatively large, and the light source image formed on the rear focal plane by the reflected light from the peripheral reflection area. Is relatively small.

  Accordingly, the rear focal point in the horizontal cross section of the central portion of the lens is set at a position displaced in the front-rear direction from the rear focal point of the projection lens, and the reflected light from the central reflection region is at least in the horizontal direction by the central portion of the lens. When diffused to form a diffused area of the lamp light distribution pattern, this diffused area is projected so that a relatively large image formed on the rear focal plane of the projection lens is stretched in the horizontal direction. It can be formed by the irradiated light distribution pattern, and it can be reduced in uneven light distribution.

  On the other hand, if the reflected light from the peripheral reflection region is made substantially parallel light by the peripheral portion of the lens to form a high light intensity region of the lamp light distribution pattern, this high light intensity region becomes the rear focal plane of the projection lens. A relatively small image formed above can be formed by a spot-like light distribution pattern projected and irradiated as it is, and the central luminous intensity can be sufficiently increased.

  As described above, according to the present invention, in the projector-type vehicle headlamp, the central luminous intensity of the lamp light distribution pattern formed by the vehicle headlamp can be sufficiently increased, and unevenness of the light distribution can be reduced. Can be minimized. Thereby, the visibility of the road surface ahead of the vehicle can be enhanced.

  In the above configuration, if the rear focal point in the vertical cross section of the central portion of the lens is set in the vicinity of the rear focal point of the projection lens, the light distribution pattern formed by the light emitted from the central portion of the lens is set in the vertical direction. Can be a horizontally long light distribution pattern that diffuses in the left-right direction with little diffusion, which can be made more suitable for forming a diffusion region of a lamp light distribution pattern.

  In the above configuration, the outer shape of the central portion of the lens is not particularly limited as described above, but if this is set to be a substantially elliptical shape when viewed from the front of the lamp, the design of the projection lens can be changed to the design of a normal projection lens. Can be quite different. Further, in this case, the width of the lens peripheral portion becomes narrower on both the upper and lower sides of the optical axis, but the light source extends along the optical axis in the portion located on the upper and lower sides of the optical axis in the lens peripheral portion. In the case of a line segment light source, a vertically long light source image that causes uneven light distribution is projected and irradiated, so reducing the width effectively reduces uneven light distribution of the lamp light distribution pattern. Can be suppressed.

  In this case, large step portions are formed between the lens central portion and the lens peripheral portion on both the left and right sides of the lens central portion. At that time, if the rear focal point in the horizontal section of the central part of the lens is set in front of the rear focal point of the projection lens, the light emitted from the central part of the lens is deflected in the direction closer to the optical axis with respect to the horizontal direction. Can be made. As a result, the emitted light from the central portion of the lens can be diffused in the left-right direction without being blocked by the step portions on the left and right sides.

  On the other hand, the design of the projection lens can be made quite different from the design of a normal projection lens even when the outer shape of the central portion of the lens is set to be a substantially oblong shape when viewed from the front of the lamp. In this case, if the rear focal point in the horizontal cross section of the central portion of the lens is set behind the rear focal point of the projection lens, the curvature of the horizontal cross section of the central portion of the lens is reduced. It is possible to prevent the wall thickness from becoming excessive. In this case, the emitted light from the center of the lens is directed away from the optical axis with respect to the horizontal direction, but the outer shape of the center of the lens is set to a horizontally long substantially elliptical shape. In this case, since large stepped portions are not formed on both the left and right sides of the central portion of the lens, the emitted light from the central portion of the lens is hardly shielded by the stepped portions on both the left and right sides, and in the left and right direction. Can be diffused.

  In the above configuration, the center of the lens is divided into the upper half of the lens and the lower half of the lens with the horizontal plane including the optical axis as the boundary, and the rear focal point in the vertical cross section of the upper half of the lens is projected. If the rear focal point of the lens is set to the rear side and the rear focal point in the vertical cross section of the lower half of the lens is set to the front side of the rear focal point of the projection lens, the following effects are obtained. An effect can be obtained.

  In other words, in this case, the light emitted from the upper half of the lens and the lower half of the lens are both slightly upward with respect to the optical axis, so the brightness of the lower end of the lamp light distribution pattern is suppressed. Thus, it is possible to prevent the short distance area on the road surface ahead of the vehicle from becoming too bright, and to increase the distance visibility.

  In the above configuration, if the reflector has a reflecting surface in which a vertical cross-sectional shape is formed by an ellipse having a point near the light source as the first focal point and a point near the rear focal point of the projection lens as the second focal point. The reflected light from the reflector can be substantially converged to the rear focal point of the projection lens with respect to the vertical direction, so that the vertical width of the lamp light distribution pattern can be prevented from becoming excessive.

  In this case, if the reflecting surface of the reflector is formed of a spheroid, the reflector can be formed with low cost and high accuracy. In this case, the reflected light from the reflector is substantially converged on the rear focal point of the projection lens in the left-right direction, but the lens central portion of the projection lens has a left-right diffusion function. Therefore, a horizontally long lamp light distribution pattern can be formed.

  In these cases, the reflecting surface of the reflector is divided into an upper half portion of the reflecting surface and a lower half portion of the reflecting surface with a horizontal plane including the optical axis as a boundary, and the first half of the upper half portion of the reflecting surface is formed. If the focal point is positioned rearward of the light emission center of the light source and the first focal point of the lower half of the reflecting surface is positioned forward of the light emission center of the light source, the following effects can be obtained. Can do.

  That is, in this case, the light source image formed on the rear focal plane of the projection lens by the reflected light from the upper half of the reflecting surface and the lower half of the reflecting surface is slightly below the optical axis. Since it is formed at the displaced position, the inverted projection image by the projection lens is formed at a position displaced slightly upward with respect to the optical axis, thereby suppressing the brightness at the lower end of the lamp light distribution pattern. Can do. And it can prevent that the near field area | region of a vehicle front road surface becomes bright too much, and can improve the distant visibility.

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

FIG. 1 is a front view showing a vehicle headlamp 10 according to an embodiment of the present invention. Also, FIG. 2 shows II-II in FIG.
FIG. 3 is a sectional view taken along line III-III in FIG.

  As shown in these drawings, the vehicle headlamp 10 according to the present embodiment is configured as a projector-type lamp unit that performs light irradiation for forming a high-beam light distribution pattern, and is not shown. It is designed to be used in a state of being incorporated in the

  The vehicle headlamp 10 includes a projection lens 12 disposed on an optical axis Ax extending in the longitudinal direction of the vehicle, a light source 14a disposed behind the rear focal point F of the projection lens 12, and the light source. A reflector 16 that reflects light from 14 a toward the front toward the optical axis Ax, and a holder 18 that connects the reflector 16 and the projection lens 12 are provided.

  FIG. 4 is a perspective view showing the projection lens 12 as a single item.

  As shown in the figure, the projection lens 12 is a double convex Fresnel lens deformed from a plano-convex aspherical lens having a convex front surface and a flat rear surface. It has such a shape. The projection lens 12 projects and irradiates the image on the focal plane including the rear focal point F as a reverse image on the vertical virtual screen arranged in front of the lamp.

  The projection lens 12 includes a lens central portion 12A located in the vicinity of the optical axis Ax, and a lens peripheral portion 12B surrounding the lens central portion 12A. Each of the lens central portion 12A and the lens peripheral portion 12B has a circular outer shape when viewed from the front of the lamp, and a conical step portion 12a close to a cylinder is formed between the two.

  The lens peripheral portion 12B is configured as a part of the plano-convex aspheric lens described above, and the rear focal point thereof coincides with the rear focal point F of the projection lens 12.

  On the other hand, the rear focal point in the vertical cross section of the lens central portion 12A coincides with the rear focal point F of the projection lens 12, but the rear focal point in the horizontal cross section is the rear focal point of the projection lens 12. The position is set at a point A on the optical axis Ax that is displaced slightly forward from F.

  The light source bulb 14 is a discharge bulb such as a metal halide bulb having a discharge light emitting portion as the light source 14a, and is inserted into the rear top opening portion 16b of the reflector 16, and the light source 14a has the light on the optical axis Ax. The line segment light source extends along the axis Ax.

  The reflector 16 has a reflecting surface 16a composed of a spheroid having the optical axis Ax as a central axis. At this time, the first ellipse of the spheroid constituting the reflecting surface 16a is set at the light emission center of the light source 14a, and the second focus is set at the rear focus F of the projection lens 12. Yes. As a result, the reflector 16 reflects the light from the light source 14a toward the front toward the optical axis Ax and converges it to the position of the rear focal point F of the projection lens 12, and diverges from the rear focal point F. The light is incident on the projection lens 12 as light.

  The holder 18 is a substantially cylindrical member disposed between the projection lens 12 and the reflector 16, and fixedly supports the projection lens 12 at the front end portion thereof, and is fixedly supported by the reflector 16 at the rear end portion thereof. Thus, the projection lens 12 and the reflector 16 are positioned in the above positional relationship.

  Next, the effect of this embodiment is demonstrated.

  As shown in FIG. 2, the reflected light from the reflector 16 incident on the projection lens 12 is forward as light parallel to the optical axis Ax in both the lens central portion 12A and the lens peripheral portion 12B in the vertical cross section. To exit.

  On the other hand, as shown in FIG. 3, in the horizontal section, the reflected light from the reflector 16 incident on the projection lens 12 is emitted forward as light parallel to the optical axis Ax at the lens peripheral edge portion 12B. In the lens central portion 12A, the rear focal point A in the horizontal cross section of the lens central portion 12A is displaced more forward than the rear focal point F of the projection lens 12, so that it deflects toward the optical axis Ax and moves in the horizontal direction. The light is emitted forward as light diffusing to.

  FIG. 5 is a perspective view of a high-beam light distribution pattern PH 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 according to the present embodiment. FIG.

  This high beam light distribution pattern PH is a combined light distribution pattern of a light distribution pattern PA formed by light emitted from the lens central portion 12A and a light distribution pattern PB formed by light emitted from the lens peripheral portion 12B. The hot zone HZ that is formed and that is the high luminous intensity region is located in the vicinity of HV that is a vanishing point in the front direction of the lamp.

  The light distribution pattern PA is formed as a horizontally long light distribution pattern that extends widely in the left-right direction with HV as the center, thereby constituting a diffusion region of the high-beam light distribution pattern PH. The light distribution pattern PA is formed as a horizontally long light distribution pattern that spreads in the left-right direction around HV as described above. The light emitted from the lens central portion 12A is formed on both the left and right sides in the horizontal direction. This is because it does not diffuse in the vertical direction.

  On the other hand, the light distribution pattern PB is formed as a spot-shaped light distribution pattern centered on HV, and thereby forms a hot zone HZ of the high-beam light distribution pattern PH. The light distribution pattern PB is formed as a spot-shaped light distribution pattern centered on HV in this way because the light emitted from the lens peripheral portion 12B is not diffused in both the vertical and horizontal directions. Is.

  As described above in detail, the vehicular headlamp 10 according to the present embodiment is configured as a projector-type vehicular headlamp. The vehicular headlamp 10 reflects from the reflector 16 and passes through the projection lens 12. The high-beam light distribution pattern PH is formed as a lamp light distribution pattern by the light of the projection light 12. The projection lens 12 includes a lens central portion 12A located near the optical axis Ax, and the lens central portion 12A. The rear focal point A in the horizontal cross section of the central portion 12A of the lens is set at a position displaced forward from the rear focal point F of the projection lens 12, and the lens. The central portion 12A diffuses the reflected light from the reflector 16 in the horizontal direction to form a diffusion region of the high beam light distribution pattern PH, and its lens. The edges 12B, since the reflected light from the reflector 16 into parallel light so as to form a hot zone HZ of the high beam light distribution pattern PH, it is possible to obtain the following effects.

  In other words, in the projector-type vehicle headlamp 10 according to the present embodiment, the reflected light from the reflector 16 is reflected from the central reflection region located relatively close to the light source 14a on the reflecting surface 16a. 12 enters the lens central portion 12A, and the reflected light from the peripheral reflection region located relatively far from the light source 14a enters the lens peripheral portion 12B of the projection lens 12. At that time, the light source image formed on the rear focal plane of the projection lens 12 by the reflected light from the central reflecting area of the reflecting surface 16a is relatively large, and the rear side is reflected by the reflected light from the peripheral reflecting area of the reflecting surface 16a. The light source image formed on the focal plane is relatively small.

  Accordingly, as in the present embodiment, the rear focal point A in the horizontal cross section of the lens central portion 12A is set to a position displaced forward from the rear focal point F of the projection lens 12, and reflected by the lens central portion 12A. If the diffused light of the high-beam light distribution pattern PH is formed by diffusing the reflected light from the central reflective region of the surface 16a in the horizontal direction, this diffused region is formed on the rear focal plane of the projection lens 12. The formed relatively large image can be formed by the light distribution pattern PA projected and irradiated so as to be stretched in the horizontal direction, and the light distribution unevenness can be reduced.

  Further, as in the present embodiment, by using the lens peripheral portion 12B, the reflected light from the peripheral reflection region of the reflective surface 16a is converted into parallel light so as to form the hot zone HZ of the high beam light distribution pattern PH. This hot zone HZ can be formed by a spot-like light distribution pattern PB on which a relatively small image formed on the rear focal plane of the projection lens 12 is projected and irradiated as it is, and its central luminous intensity is sufficiently increased. be able to.

  As described above, according to the present embodiment, in the projector-type vehicle headlamp 10, the central luminous intensity of the high-beam light distribution pattern PH formed by the vehicle headlamp 10 can be sufficiently increased. The uneven light distribution can be minimized. Thereby, the visibility of the road surface ahead of the vehicle can be enhanced.

  In particular, in the present embodiment, the rear focal point in the vertical cross section of the lens central portion 12A is set at the rear focal point F of the projection lens 12, so that it is formed by light emitted from the lens central portion 12A. The light distribution pattern PA can be a horizontally long light distribution pattern that diffuses in the left-right direction without diffusing in the vertical direction, which is more suitable for forming the diffusion region of the high-beam light distribution pattern PH. be able to.

  In the present embodiment, the projection lens 12 has a shape obtained by deforming a plano-convex aspherical lens into a double Fresnel lens shape, so that the design is different from that of a normal projection lens. In addition, the thickness can be reduced.

  At this time, a stepped portion 12a that rises forward is formed around the lens central portion 12A. The rear focal point A in the horizontal cross section of the lens central portion 12A is higher than the rear focal point F of the projection lens 12. Also, the light emitted from the lens central portion 12A is deflected in the direction closer to the optical axis Ax with respect to the horizontal direction, so that the light emitted from the lens central portion 12A is stepped on the right and left sides. It can be diffused in the left-right direction without being blocked by 12a.

  Furthermore, in the present embodiment, the reflecting surface 16a of the reflector 16 is composed of a spheroid having the light emission center of the light source 14a as the first focus and the rear focus F of the projection lens 12 as the second focus. The reflector 16 can be accurately formed at low cost. The reflected light from the reflecting surface 16a of the reflector 16 converges on the rear focal point F of the projection lens 12 and enters the projection lens 12 as divergent light from the rear focal point F. Twelve optical designs can be easily performed.

  In the above embodiment, the reflecting surface 16a of the reflector 16 has been described as being constituted by a spheroid, but it is also possible to adopt a reflecting surface obtained by slightly deforming this spheroid. is there. In this case, since the reflected light from the reflecting surface is slightly deteriorated in convergence to the rear focal point F of the projection lens 12, the high beam distribution pattern formed by the reflected light is a high beam. Compared with the light distribution pattern PH, the light condensing performance as a whole is slightly deteriorated. Therefore, even in this case, the vertical cross-sectional shape of the reflection surface is configured by an ellipse having the light emission center of the light source 14a as the first focus and the rear focus F of the projection lens 12 as the second focus. Is preferred.

  In the above embodiment, the projection lens 12 is described as having a shape obtained by deforming a plano-convex aspherical lens into a double Fresnel lens shape. The surface is formed so that the lens center portion 12A and the lens peripheral edge portion 12B are flush with each other at the upper and lower ends of the lens center portion 12A, and only the left and right side portions of the lens center portion 12A are substantially a crescent from an aspherical surface. It is also possible to set the shape so as to be depressed into a shape.

  Further, in the above embodiment, the case where the high beam light distribution pattern PH is formed as the lamp light distribution pattern has been described. Of course, other light distribution patterns can be formed. It is possible to form a low beam light distribution pattern or the like by arranging a shade or the like in the vicinity of the rear focal point F.

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

  First, a first modification of the above embodiment will be described.

  FIG. 6 is a front view showing a vehicle headlamp 110 according to this modification. 7 is a cross-sectional view taken along line VII-VII in FIG. 6, and FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG.

  As shown in these drawings, the configuration of the light source bulb 14, the reflector 16, and the holder 18 of the vehicle headlamp 110 is the same as that of the above embodiment, but the configuration of the projection lens 112 is the above embodiment. It is different from the case of form.

  That is, in the projection lens 112 of this modification, as shown in FIG. 9 as a single product, the outer shape of the lens central portion 112A is set to be an elliptical shape when viewed from the front of the lamp. Compared to 12A, its vertical width is slightly wider and its lateral width is slightly narrower.

  Similar to the lens central portion 12A of the above embodiment, the lens central portion 112A has a rear focal point in the vertical cross section that matches the rear focal point F of the projection lens 112, and the rear focal point in the horizontal cross section. Is set at a point B on the optical axis Ax that is displaced somewhat forward from the rear focal point F of the projection lens 112.

  On the other hand, the lens peripheral portion 112B is configured as a part of a plano-convex aspherical lens that constitutes the projection lens 112, like the lens central portion 12A of the above embodiment, and the rear focal point is the rear side of the projection lens 112. It coincides with the focal point F.

  Next, the effect of this modification is demonstrated.

  As shown in FIG. 7, the reflected light from the reflector 16 incident on the projection lens 112 is forward as light parallel to the optical axis Ax in both the lens central portion 112A and the lens peripheral portion 112B in the vertical cross section. To exit.

  On the other hand, as shown in FIG. 8, in the horizontal section, the reflected light from the reflector 16 incident on the projection lens 112 is emitted forward as light parallel to the optical axis Ax at the lens peripheral edge 112B. In the lens central portion 112A, the rear focal point B in the horizontal cross section of the lens central portion 112A is displaced forward from the rear focal point F of the projection lens 112. Light is emitted forward as light diffusing in the direction.

  FIG. 10 is a perspective view of a high beam light distribution pattern PH formed on a virtual vertical screen disposed at a position 25 m ahead of the lamp by light irradiated forward from the vehicle headlamp 110 according to this modification. FIG.

  As in the case of the above-described embodiment, the high-beam light distribution pattern PH is a light distribution pattern PA formed by the light emitted from the lens central portion 112A and a light distribution pattern formed by the light emitted from the lens peripheral portion 112B. It is formed as a synthetic light distribution pattern with PB, and its hot zone HZ is located in the vicinity of HV.

  At this time, the light distribution pattern PA is formed as a horizontally long light distribution pattern that extends widely in the left-right direction with HV as the center, as in the case of the above-described embodiment, thereby diffusing the high-beam light distribution pattern PH. It constitutes an area.

  The light distribution pattern PB is also formed as a spot-shaped light distribution pattern centered on HV, as in the case of the above-described embodiment, thereby forming a hot zone HZ of the high-beam light distribution pattern PH. ing. However, the light distribution pattern PB is a flat light distribution pattern having a slightly narrower vertical width and a slightly wider left-right width than the light distribution pattern PB ′ formed in the above embodiment.

  The light distribution pattern PB is formed as a flat light distribution pattern in this way for the following reason.

  That is, in the projection lens 112, portions located on both the upper and lower sides of the optical axis Ax project and irradiate a vertically long light source image, and portions located on both the left and right sides of the optical axis Ax project and illuminate a horizontally elongated light source image. In the projection lens 112, a larger light source image is projected and irradiated toward a portion located closer to the optical axis Ax.

  At this time, the lens center portion 112A has a vertically long elliptical shape that is slightly wider in the vertical width and slightly narrower in the left-right width than the lens center portion 12A of the above-described embodiment, and accordingly, the lens peripheral portion 112B. Is narrow on both the upper and lower sides of the optical axis Ax and wide on the left and right sides of the optical axis Ax. For this reason, in the light source image projected and irradiated by the lens peripheral edge portion 112B, the ratio of the light source image having a large vertical length is decreased and the ratio of the light source image having a large horizontal length is increased as compared with the case of the above embodiment. Therefore, the light distribution pattern PB formed by superimposing these light source images is a flat light distribution pattern.

  Even in the case of adopting the configuration of this modification, it is possible to obtain the same effects as those of the above embodiment.

  In addition, by adopting the configuration of this modification, the light distribution pattern PB formed in a spot shape can be a flat light distribution pattern, so that the lower end portion of the light distribution pattern PB is on the road surface in front of the vehicle. The risk of forming a light pool can be reduced, thereby making it possible to more effectively suppress uneven light distribution in the high beam light distribution pattern PH.

  Note that the width of the upper and lower side portions of the optical axis Ax in the lens center portion 112A is increased by the amount that the width of the upper and lower side portions of the optical axis Ax in the lens peripheral portion 112B is reduced, and a light source image having a large vertical length is formed from that portion. Although the projection light is irradiated, the emitted light from the lens central portion 112A is diffused in the left-right direction, so that the light source image having a large vertical length is stretched in the left-right direction to form a part of the light distribution pattern PA. Thus, compared to the case where the light source image is projected and irradiated as it is like the light distribution pattern PB, the effect of suppressing the light distribution unevenness can be enhanced.

  In the present modification, the outer shape of the lens center portion 112A is set to be a vertically long oval shape when viewed from the front of the lamp, and therefore, on the left and right sides, a step portion 112a that is higher than the step portion 12a of the above embodiment. However, also in this modified example, the rear focal point B in the horizontal cross section of the lens central portion 112A is set in front of the rear focal point F of the projection lens 112, and the lens central portion 112A. Since the light emitted from the lens is deflected in the direction closer to the optical axis Ax with respect to the horizontal direction, the light emitted from the lens central portion 112A is diffused in the left-right direction without being blocked by the step portions 112a on both the left and right sides. Can do.

  Furthermore, in the present embodiment, the projection lens 112 has a shape obtained by deforming a plano-convex aspheric lens into a double Fresnel lens shape, and the lens center portion 112A has an oblong outer shape. Since it has a shape, the design can be made quite different from the design of a normal projection lens, and the thickness can be reduced.

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

FIG. 11 is a front view showing a vehicle headlamp 210 according to this modification. FIG. 12 shows the XII-XII of FIG.
It is line sectional drawing.

  As shown in these drawings, the configuration of the light source bulb 14, the reflector 16, and the holder 18 of the vehicle headlamp 210 is the same as that of the above embodiment, but the configuration of the projection lens 212 is the above embodiment. It is different from the case of form.

  In other words, the projection lens 212 of the present modification has an outer shape of the lens center portion 212A set to be a horizontally long oval shape when viewed from the front of the lamp, and its vertical width compared to the lens center portion 12A of the above embodiment. Is slightly narrower and its left and right widths are slightly wider.

  In the lens center portion 212A, the rear focal point in the vertical cross section coincides with the rear focal point F of the projection lens 212, and the rear focal point in the horizontal cross section is more than the rear focal point F of the projection lens 212. Also, the position is set at a point C on the optical axis Ax that is displaced somewhat rearward.

  On the other hand, the lens peripheral portion 212B is configured as a part of a plano-convex aspherical lens that constitutes the projection lens 212, like the lens peripheral portion 12B of the above embodiment, and the rear focal point is the rear side of the projection lens 212. It coincides with the focal point F.

  Next, the effect of this modification is demonstrated.

  Reflected light from the reflector 16 that has entered the projection lens 212 is emitted forward as light parallel to the optical axis Ax in both the lens central portion 212A and the lens peripheral portion 212B within the vertical cross section.

  On the other hand, as shown in FIG. 12, in the horizontal cross section, the reflected light from the reflector 16 incident on the projection lens 212 is emitted forward as light parallel to the optical axis Ax at the lens peripheral portion 212B. In the lens central portion 212A, the rear focal point C in the horizontal section of the lens central portion 212A is displaced rearward from the rear focal point F of the projection lens 212, so that it deflects away from the optical axis Ax. Then, it is emitted forward as light that diffuses in the left-right direction.

  Even in the case of adopting the configuration of this modification, it is possible to obtain the same effects as those of the above embodiment.

  In addition, in the present embodiment, the projection lens 212 has a shape that is obtained by deforming a plano-convex aspheric lens into a double Fresnel lens shape, and the lens central portion 212A has a laterally elliptical outer shape. Since it has a shape, the design can be made quite different from the design of a normal projection lens, and the thickness can be reduced.

  At that time, since the rear focal point C in the horizontal cross section of the lens central portion 212A is set to the rear side of the rear focal point F of the projection lens 212, the curvature of the horizontal cross section of the lens central portion 212A is reduced. It is possible to prevent the wall thickness from becoming excessive.

  In this case, the emitted light from the lens central portion 212A is directed in a direction away from the optical axis Ax with respect to the horizontal direction, but the outer shape of the lens central portion 212A is set to a horizontally long substantially oval shape. Since the step portions 212a on both the left and right sides are not so large, the emitted light from the lens center portion 212A is diffused in the left and right directions without being blocked by the step portions 212a on both the left and right sides. Can be made.

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

  FIG. 13 is a side sectional view showing a vehicle headlamp 310 according to this modification.

  As shown in the figure, the vehicular headlamp 310 has the same configuration of the light source bulb 14, reflector 16 and holder 18 as in the above embodiment, but the configuration of the projection lens 312 has the above embodiment. It is different from the case of.

  That is, the projection lens 312 of the present modification has a lens central portion 312A divided into a lens upper half 312A1 and a lens lower half 312A2 with a horizontal plane including the optical axis Ax as a boundary.

  At that time, the rear focal point D1 in the vertical cross section of the lens upper half 312A1 is set behind the rear focal point F of the projection lens 12, and the lower lens half 312A2 is in the vertical cross section. The rear focal point D <b> 2 is set in front of the rear focal point F of the projection lens 12. As a result, both the upper lens half 312A1 and the lower lens half 312A2 deflect the reflected light from the reflector 16 slightly upward and emit it as light slightly upward with respect to the optical axis Ax. It is like that.

  However, the rear focal points in the horizontal cross section of the upper half portion 312A1 and the lower half portion 312A2 of each lens coincide with the rear focal point F of the projection lens 312.

  On the other hand, the lens peripheral edge 312B of the projection lens 312 is configured as a part of a plano-convex aspherical lens that constitutes the projection lens 312 as with the lens peripheral edge 12B of the above embodiment, and the rear focal point is the projection lens. 312 coincides with the rear focus F.

  FIG. 14 is a perspective view of a high beam light distribution pattern PH formed on a virtual vertical screen disposed at a position 25 m ahead of the lamp by light irradiated forward from the vehicle headlamp 310 according to this modification. FIG.

  As in the case of the above-described embodiment, the high-beam light distribution pattern PH is a light distribution pattern PA formed by light emitted from the lens central portion 312A and a light distribution pattern formed by light emitted from the lens peripheral portion 312B. It is formed as a synthetic light distribution pattern with PB, and its hot zone HZ is located in the vicinity of HV.

  As in the case of the above embodiment, the light distribution pattern PA is formed as a horizontally long light distribution pattern that extends widely in the left-right direction around HV, thereby forming a diffusion region of the high-beam light distribution pattern PH. is doing. However, the light distribution pattern PA is formed at a position slightly displaced upward as compared to the light distribution pattern PA ′ formed in the above embodiment. This is because light emitted from the upper half portion 312A1 and the lower half portion 312A2 of the lens central portion 312A is light emitted slightly upward with respect to the optical axis Ax.

  On the other hand, the light distribution pattern PB is formed as a spot-shaped light distribution pattern centered on HV as in the case of the above-described embodiment, thereby constituting a hot zone HZ of the high-beam light distribution pattern PH. ing.

  Even in the case of adopting the configuration of this modification, it is possible to obtain the same effects as those of the above embodiment.

  Moreover, by adopting the configuration of this modification, the light distribution pattern PA can be formed at a position slightly displaced upward as compared to the light distribution pattern PA ′ formed in the above embodiment. The brightness of the lower end portion of the high beam light distribution pattern PH can be suppressed while maintaining the position of the hot zone HZ in the vicinity of HV. And it can prevent that the near field area | region of a vehicle front road surface becomes bright too much, and can improve the distant visibility.

  Next, the 4th modification of the said embodiment is demonstrated.

  FIG. 15 is a side sectional view showing a vehicle headlamp 410 according to this modification.

  As shown in the figure, the vehicular headlamp 410 has the same configuration of the projection lens 12, the light source bulb 14 and the holder 18 as in the above embodiment, but the configuration of the reflector 416 is the same as in the above embodiment. It is different from the case of.

  That is, the reflector 416 of the present modification has a reflective surface 416a that is divided into a reflective surface upper half 416a1 and a reflective surface lower half 416a2 with a horizontal plane including the optical axis Ax as a boundary.

  At that time, the upper half portion 416a1 of the reflecting surface is set such that the first focal point E1 of the spheroid surface constituting the reflecting surface is located behind the light emission center of the light source 14a, and the lower half portion 416a2 of the reflecting surface is The first focal point E2 of the spheroid forming this is positioned in front of the light emission center of the light source 14a. Note that the second focal point of each spheroid constituting the upper half 416a1 and the lower half 416a2 of the reflecting surface is set to the rear focal point F of the projection lens 12. As a result, the light source image formed on the rear focal plane of the projection lens 12 by the reflected light from the upper half 416a1 and the lower half 416a2 of the reflecting surface is slightly below the optical axis Ax. It is formed at a displaced position.

  FIG. 16 is a perspective view of a high beam light distribution pattern PH formed on a virtual vertical screen disposed at a position 25 m ahead of the lamp by light irradiated forward from the vehicle headlamp 410 according to this modification. FIG.

  As in the case of the above-described embodiment, the high-beam light distribution pattern PH is a light distribution pattern PA formed by light emitted from the lens center portion 312A and a light distribution pattern formed by light emitted from the lens peripheral portion 312B. It is formed as a synthetic light distribution pattern with PB, and its hot zone HZ is located in the vicinity of HV.

  As in the case of the above embodiment, the light distribution pattern PA is formed as a horizontally long light distribution pattern that extends widely in the left-right direction around HV, thereby forming a diffusion region of the high-beam light distribution pattern PH. is doing. However, the light distribution pattern PA has a shape obtained by slightly deforming the light distribution pattern PA ′ formed in the above embodiment, and is formed at a position slightly displaced upward as compared to the light distribution pattern PA ′. .

  On the other hand, the light distribution pattern PB is formed as a spot-shaped light distribution pattern having substantially the center HV as in the case of the above-described embodiment, thereby forming a hot zone HZ of the high-beam light distribution pattern PH. is doing. However, the light distribution pattern PB has a shape obtained by slightly deforming the light distribution pattern PB ′ formed in the above embodiment, and is formed at a position slightly displaced upward compared to the light distribution pattern PB ′. .

  As described above, the light distribution patterns PA and PB are slightly deformed with respect to the light distribution patterns PA ′ and PB ′, and are slightly displaced upward. The light source image formed on the rear focal plane of the projection lens 12 by the reflected light from the lower half 416a2 of the reflection surface is formed at a position slightly displaced downward with respect to the optical axis Ax. This is because the reverse projection image is formed at a position displaced slightly upward with respect to the optical axis Ax.

  This point will be described in detail with reference to FIG.

  FIG. 17A is a view showing an image of the light source 14a formed on the virtual vertical screen by the light emitted from the lens central portion 12A, and FIG. 17B shows the light emitted from the lens peripheral portion 12B. It is a figure which shows the image of the light source 14a formed on the said virtual vertical screen.

  As shown in FIG. 17A, if the lens center portion 12A does not have a left-right diffusion function, the light source image IA ′ formed by the light emitted from the lens center portion 12A of the above embodiment is Whereas the center point is radially formed so as to be located at HV, the light source image IA formed by the emitted light from the lens central portion 12A of the present modification is lower than the center point. It is formed in a radial pattern so that the close points are located at HV. Actually, since the lens center portion 12A has a left-right diffusion function, the light source image IA formed radially is stretched in the left-right direction to form a light distribution pattern PA.

  Further, as shown in FIG. 17B, the light source image IB ′ formed by the light emitted from the lens peripheral edge portion 12B of the above embodiment is formed radially so that the center point thereof is located at HV. On the other hand, the light source image IB formed by the light emitted from the lens peripheral edge portion 12B of the present modification is radially arranged such that a point closer to the lower end than the center point is located at HV. It is formed. And since the lens peripheral part 12B does not have a right-and-left diffusion function, the light source image IB formed radially is superimposed as it is, and the light distribution pattern PB is formed.

  Even in the case of adopting the configuration of this modification, it is possible to obtain the same effects as those of the above embodiment.

  In addition, by adopting the configuration of this modification, the light distribution patterns PA and PB are slightly displaced upward as compared to the light distribution patterns PA ′ and PB ′ formed in the above embodiment. Can be formed. At this time, these light distribution patterns PA and PB are formed based on the light source images IA and IB formed radially with HV as the center. Even though it is displaced upward, the maximum luminous intensity position can be maintained in the vicinity of HV.

  Accordingly, it is possible to suppress the brightness of the lower end portion of the high beam light distribution pattern PH while maintaining the maximum luminous intensity position of the hot zone HZ of the high beam light distribution pattern PH in the vicinity of HV. As a result, it is possible to effectively prevent the short distance region on the road surface ahead of the vehicle from becoming too bright, and to further improve the distance visibility.

  In addition, it is also possible to employ | adopt structures other than the said embodiment and each modification, and it is also possible to set it as the structure which combined these suitably.

The front view which shows the vehicle headlamp which concerns on one Embodiment of this invention II-II sectional view of Fig. 1 Sectional view along line III-III in Fig. 1 The perspective view which shows the projection lens of the said vehicle headlamp separately The figure which shows perspectively the light distribution pattern for high beams formed on the virtual vertical screen arrange | positioned by the light irradiated ahead from the said vehicle headlamp at the position of the lamp front 25m. The front view which shows the vehicle headlamp which concerns on the 1st modification of the said embodiment. Sectional view taken along line VII-VII in FIG. VIII-VIII sectional view of FIG. The perspective view which shows the projection lens of the vehicle headlamp shown in FIG. FIG. 6 is a perspective view of a high beam light distribution pattern formed on the virtual vertical screen by light emitted forward from the vehicle headlamp shown in FIG. 6. The front view which shows the vehicle headlamp which concerns on the 2nd modification of the said embodiment. XII-XII line cross section of Fig. 11 Side sectional view which shows the vehicle headlamp which concerns on the 3rd modification of the said embodiment. The figure which shows in perspective the light distribution pattern for high beams formed on the said virtual vertical screen by the light irradiated ahead from the vehicle headlamp shown in FIG. Side sectional view which shows the vehicle headlamp which concerns on the 4th modification of the said embodiment. The figure which shows in perspective the light distribution pattern for high beams formed on the said virtual vertical screen by the light irradiated ahead from the vehicle headlamp shown in FIG. It is a figure which shows the image of the light source formed on the said virtual vertical screen with the vehicle headlamp shown in FIG. 15, Comprising: The same figure (a) is formed with the emitted light from the lens center part of the projection lens. The figure which shows the light source image to be performed, The figure (b) is a figure which shows the light source image formed with the emitted light from the lens peripheral part of the projection lens

Explanation of symbols

10, 110, 210, 310, 410 Vehicle headlamp 12, 112, 212, 312 Projection lens 12A, 112A, 212A, 312A Lens central portion 12B, 112B, 212B, 312B Lens peripheral portion 12a, 112a, 212a Stepped portion 14 Light source bulb 14a Light source 16, 416 Reflector 16a, 416a Reflective surface 16b Rear top opening 18 Holder 312A1 Lens upper half 312A2 Lens lower half 416a1 Reflective surface upper half 416a2 Reflective surface lower half A, B, C Lens center Rear focal point in horizontal section of part Ax Optical axis D1 Rear focal point in vertical section of upper half of lens D2 Rear focal point in vertical section of lower half of lens E1, E2 First focal point F Rear focal point HZ Hot Zone IA, IA ′, IB, IB ′ Light source image PA, PA ′, PB, PB 'Light distribution pattern PH High beam light distribution pattern

Claims (8)

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 configured to form a predetermined lamp light distribution pattern by the light from the light source reflected by the reflector and transmitted through the projection lens.
The projection lens is composed of a lens central part located in the vicinity of the optical axis, and a lens peripheral part surrounding the lens central part,
The rear focal point in the horizontal cross section of the central portion of the lens is set at a position displaced in the front-rear direction from the rear focal point of the projection lens, and the reflected light from the reflector is at least horizontally transmitted by the central portion of the lens. The diffused region of the lamp light distribution pattern is diffused to form a high luminous intensity region of the lamp light distribution pattern by making the reflected light from the reflector substantially parallel light by the lens periphery. A vehicle headlamp characterized by the above.   The vehicular headlamp according to claim 1, wherein a rear focal point in a vertical section of the central portion of the lens is set in the vicinity of the rear focal point of the projection lens. The outer shape of the central part of the lens is set to be a substantially elliptical shape that is vertically long in the front view of the lamp,
The vehicular headlamp according to claim 1 or 2, wherein a rear focal point in a horizontal cross section of the central portion of the lens is set in front of a rear focal point of the projection lens. The outer shape of the center of the lens is set to be a substantially elliptical shape that is horizontally long in the front view of the lamp,
The vehicular headlamp according to claim 1 or 2, wherein a rear focal point in a horizontal cross section of the central portion of the lens is positioned rearward of the rear focal point of the projection lens. The lens center is divided into a lens upper half and a lens lower half with a horizontal plane including the optical axis as a boundary.
The rear focal point in the vertical cross section of the upper half of the lens is set on the rear side of the rear focal point of the projection lens,
5. The vehicle front according to claim 1, wherein a rear focal point in a vertical cross section of the lower half of the lens is set in front of a rear focal point of the projection lens. Lighting.   The reflector has a reflecting surface in which a vertical cross-sectional shape is formed by an ellipse having a point near the light source as a first focal point and a point near the rear focal point of the projection lens as a second focal point. The vehicle headlamp according to any one of claims 1 to 5, wherein:   The vehicular headlamp according to claim 6, wherein the reflecting surface of the reflector is formed of a spheroidal surface. The reflection surface of the reflector is divided into an upper half of the reflection surface and a lower half of the reflection surface with a horizontal plane including the optical axis as a boundary.
The first focal point of the upper half of the reflecting surface is set behind the light emission center of the light source,
The vehicular headlamp according to claim 6 or 7, wherein the first focal point of the lower half of the reflecting surface is positioned in front of the light emission center of the light source.

Images