JPH1125710A - Headlamp for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To fully secure a radiation light to a road surface immediately in front of a vehicle, in the case of providing a reflector having the function of controlling the luminous intensity distribution. SOLUTION: At a boundary B (namely a high position in the inside of a lighting fixture) between a reflecting surface 16a and an upper wall surface 16b of a reflector 16, a plurality of supplementary reflection surface elements 22s are formed which diffuse and reflect light of an illuminant bulb 18 in the vertical direction, right and left more downwards than a horizontal line, and the reflected light is radiated to a forward direction of the vehicle as a downward diffused light (an additional luminous intensity distribution pattern) without being disturbed by a shade 20 or the like. Accordingly, this headlamp fully radiates on a road surface immediately in the front of the vehicle, where the light is apt to be radiated insufficiently in a sub-lamp luminous intensity distribution pattern, formed with a reflecting surface 16a. Then, since the additional luminous intensity distribution pattern is radiated to not only the road surface immediately in front of the vehicle but also the further front in the road over a comparatively wide area, and the generation of radiation in homogeneity is effectively controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle headlamp provided with a reflector having a light distribution control function.

[0002]

2. Description of the Related Art In a recent vehicle headlamp, a predetermined light distribution pattern is formed by controlling reflection of light from a light source bulb using a reflector instead of controlling refraction of parallel reflected light from a reflector by a lens step. In many cases, such a configuration is adopted. By giving the light distribution control function to the reflector in this way, the lens can be made transparent or close to the lens, thereby increasing the transparency of the lamp and improving its appearance.

[0003]

However, such a vehicle headlamp having a light distribution control function in the reflector has a problem that the irradiation light on the road surface immediately before the vehicle tends to be insufficient.

That is, when a lens is divided into a large number of lens steps, a part of the lens steps is used to deflect parallel reflected light from the reflector downward to illuminate the road surface immediately before the vehicle. Although it is relatively easy, since the reflecting surface of the reflector is provided inside the lamp rather than the front of the lamp like a lens, even if the light from the light source bulb is reflected downward, the reflected light is It is often blocked by a shade provided near the front of the light source bulb or a vehicle body bumper protruding forward from near the lower part of the lamp, so that irradiation on the road surface immediately before the vehicle is often hindered.

The present invention has been made in view of such circumstances, and in a vehicle headlamp provided with a reflector having a light distribution control function, a sufficient irradiation light to a road surface immediately before the vehicle is secured. It is an object of the present invention to provide a vehicular headlamp capable of performing the following.

[0006]

The present invention achieves the above object by forming a predetermined auxiliary reflection surface element at a boundary between a reflection surface of a reflector and an upper wall surface extending forward from an upper end edge of the reflector. It is designed to work.

That is, according to the present invention, a light source bulb and a reflector configured to form a required light distribution pattern by controlling reflection of light from the light source bulb are provided. In the vehicle headlamp provided, the reflector includes a reflection surface for forming the light distribution pattern, and an upper wall surface extending forward from an upper end edge of the reflection surface. An auxiliary reflection surface element for diffusing and reflecting light from the light source bulb in a vertical direction and a horizontal direction below a horizontal plane is formed at a boundary with the upper wall surface.

The "required light distribution pattern" means a light distribution pattern that satisfies the light distribution function to be performed by the vehicle headlamp, and may be a main light distribution pattern. The light distribution pattern may be a light distribution pattern for a sub-light or a light distribution pattern for both main and sub-lights.

The specific configuration of the "reflection surface" is not particularly limited as long as it can control the reflection of the light from the light source bulb so as to form the required light distribution pattern. May be constituted by a single free-form surface (that is, a curved surface other than a quadratic surface), may be constituted by a plurality of reflection surface elements, or may be constituted by a free-form surface and a plurality of It may be configured in combination with a reflective surface element.

The specific shape and number of the "auxiliary reflecting surface element" are not particularly limited as long as the light from the light source bulb is diffused and reflected in the vertical and horizontal directions below the horizontal plane. It is not something to be done.

[0011]

As described above, according to the present invention, the light source bulb is provided at the boundary between the reflecting surface of the reflector and the upper wall surface extending forward from the upper end edge (that is, at a high position in the lamp). The auxiliary reflection surface element for diffusing and reflecting light from the vertical direction and the horizontal direction below the horizontal plane is formed, so that the reflected light from the auxiliary reflection surface element is provided near the front of the light source bulb. It is possible to radiate downward diffused light to the front of the vehicle without being blocked by a shade or a vehicle body bumper that projects forward from near the lower part of the lamp.

Therefore, it is possible to sufficiently irradiate the road surface immediately before the vehicle, in which the light distribution pattern formed by the reflection surface is likely to be short of the irradiation light, with the reflection light from the auxiliary reflection surface element.

At this time, if the reflected light from the auxiliary reflecting surface element is irradiated only on the road surface immediately before the vehicle, the irradiation pattern formed by the reflected light and the light distribution pattern are separated from each other, and Is darker, or both patterns partially overlap and the overlapping portion becomes extremely brighter than the surrounding portion, and the seam between the two patterns tends to be unevenly illuminated. Since the element is configured to diffusely reflect the light from the light source bulb in the vertical direction and the horizontal direction, not only the road surface immediately before the vehicle but also a road surface in front thereof (a road surface at a short distance in front of the vehicle) over a relatively wide area. Irradiation can be performed, so that the irradiation pattern and the light distribution pattern do not separate from each other, and the overlapping portion of both patterns is closer to the peripheral portion. Nor it becomes extremely bright. Therefore, it is possible to effectively suppress the occurrence of irradiation unevenness on a road surface at a short distance in front of the vehicle. The above is particularly important in view of the fact that the irradiation unevenness on a road surface at a short distance in front of the vehicle is very noticeable even with a slight irradiation unevenness as compared with the irradiation unevenness on a distant road surface.

As described above, according to the present invention, in a vehicle headlamp provided with a reflector having a light distribution control function, it is possible to sufficiently secure irradiation light to a road surface immediately before a vehicle. In addition, this can be realized while effectively suppressing the occurrence of irradiation unevenness on a road surface in a short distance in front of the vehicle.

Further, according to the present invention, by providing the auxiliary reflection surface element at the boundary between the reflection surface and the upper wall surface, it is possible to increase the reflector use solid angle for light from the light source bulb. Therefore, the headlight can be made brighter.

In the above configuration, in order to diffuse and reflect the light from the light source bulb in the vertical direction, the vertical cross-sectional shape of the auxiliary reflection surface element must be a convex curve, a concave curve, or the like.
What is necessary is just to comprise a curve, such as a wavy curve, or a straight line. At this time, if the said cross-sectional shape is comprised by a convex curve as described in Claim 2, the reflected light from the said auxiliary | assistant reflective surface element will be sufficient. Since it can be distributed more to the road surface immediately before the vehicle than to the road surface in front of the vehicle, it is possible to obtain an irradiation pattern in which the brightness gradually decreases from the road surface in front of the vehicle to the road surface in front of the vehicle. This makes it possible to more effectively suppress the occurrence of irradiation unevenness due to the superposition of the irradiation pattern and the light distribution pattern.

Also, as described in claim 3, the plurality of auxiliary reflecting surface elements are juxtaposed in the left-right direction so as to straddle the right side of the light source bulb along the boundary portion. Then, the following operation and effect can be obtained.

That is, by arranging a plurality of the auxiliary reflecting surface elements in parallel, it is possible to secure more irradiation light on the road surface immediately before the vehicle, and at a position close to the position just above the light source bulb in the boundary portion. Since the light reflected by the light source is formed on the road surface as a larger irradiation pattern, the plurality of auxiliary reflection surface elements are arranged side by side so as to straddle the upper position of the light source bulb on the left and right, so that irradiation unevenness is less likely to occur. be able to.

At this time, by appropriately changing the diffusion angle between the auxiliary reflecting surface elements, it is possible to effectively suppress the occurrence of irradiation unevenness caused by the irradiation pattern itself formed by the auxiliary reflecting surface elements. can do.

As described above, the specific configuration of the reflection surface is not particularly limited. However, as described in claim 4, at least the region near the upper end edge of the reflection surface has a predetermined horizontal pitch. In the case where the auxiliary reflection surface elements are divided and formed in a plurality of reflection surface elements, if the auxiliary reflection surface elements are arranged side by side at a narrower left / right pitch than the left / right pitch of the respective reflection surface elements, the auxiliary reflection surface elements Since light distribution control with a fine grain can be performed, it is possible to more effectively suppress the occurrence of irradiation unevenness on a road surface immediately before the vehicle and a short distance in front of the vehicle.

A normal lens is provided in front of the reflector. This lens has a so-called inverted slant shape which is inclined so as to be displaced downward and rearward as described in claim 5. If you have
It is possible to irradiate the large-angle downward reflected light from the auxiliary reflecting surface element to the front of the lamp without being blocked by the lower flange portion of the lens, etc. it can. When the ground clearance at the driver's viewpoint is high, such as a truck or a bus, the driver's view can be as far as the road surface immediately before the vehicle. This configuration is particularly effective.

In the above structure, the type of the "light source bulb" is not particularly limited.
As described in the above, when a high-intensity and high-power discharge bulb is used as the light source bulb, the light distribution pattern formed by the reflected light from the reflection surface becomes very bright, and the road surface immediately before the vehicle becomes dark. It is particularly effective to form the above-mentioned auxiliary reflection surface element because it tends to be relatively dark.

[0023]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a front view showing a vehicle headlamp according to an embodiment of the present invention, and FIG. 2 is a side sectional view thereof.

As shown in these figures, a headlight 10 according to the present embodiment is a headlight mounted on a cab-over type truck, and is provided in a space formed by a lens 12 and a body 14. The reflector 16 to which the light source bulb 18 and the shade 20 are attached is provided so as to be tiltable in the up-down direction and the left-right direction, so as to form a left-side light distribution pattern P as shown in FIGS. Is configured. 3 and 4 show the headlight 1 described above.
It is a figure which shows the screen light distribution pattern of 0, and a road surface light distribution pattern.

The lens 12 is a plain lens, and is formed in an inverted slant shape which is inclined so as to be displaced rearward downward. The sub-light distribution pattern P is formed by the reflector 16. That is, the reflection surface 16a of the reflector 16
Is divided into a plurality of reflective surface elements 16s using a paraboloid of revolution centered on an axis (optical axis) Ax extending in the front-rear direction as a reference plane, and the curvature of each of the reflective surface elements 16s is set to an appropriate value. , The sub-light distribution pattern P is obtained.

An upper wall 16b and a lower wall 16c extending forward from the edge are formed at the upper and lower edges of the reflecting surface 16a of the reflector 16, respectively.
Further, a plurality of auxiliary reflection surface elements 22s for diffusing and reflecting light from the light source bulb 18 in a vertical direction and a horizontal direction toward a lower side than a horizontal plane are provided at a boundary portion B between the reflection surface 16a and the upper wall surface 16b. Are arranged side by side in the left-right direction along the boundary portion B. The juxtaposed regions of the auxiliary reflection surface elements 22a are set so as to straddle the upper position of the light source bulb 18 on the left and right, and each of the auxiliary reflection surface elements 22a is located near the upper end edge of the reflection surface 16a. Are arranged side by side at a narrower left / right pitch than the left / right pitch of the reflecting surface elements 16s. Then, these auxiliary reflection surface elements 22
The additional light distribution pattern PA is formed on the road surface on the front side of the sub-light distribution pattern P by the reflected light from s.

The light source bulb 18 is a metal halide discharge bulb whose optical axis (reference axis) coincides with the optical axis Ax of the reflector 16 and whose light emitting portion (arc) 18a is connected to the reference surface of the reflector 16 It is attached to the reflector 16 so as to be located slightly forward of the focal position F of the barrel paraboloid. The light source bulb 18 is connected to a lighting circuit (not shown) via a bulb socket 24 and a high-voltage cord 26 because a high voltage is required for lighting the light source bulb 18.

The shade 20 is connected to the light source bulb 18.
Cup-shaped tip portion 20a that covers the front of the
0a extends rearward so as to cover the lower side of the light source bulb 18 in a substantially semi-cylindrical shape, and comprises a semi-cylindrical portion 20b fixed to the reflector 16 at a rear end portion. In addition to blocking direct light from 18 toward the front of the lamp, the semi-cylindrical portion 20b blocks light from the light source bulb 18 to a lower region of the reflecting surface 22 and an upper region of the reflecting surface 16a (shown in FIG. 1). Only light incident on the two-dot chain lines L1 and L2) is allowed.

Each of the auxiliary reflection surface elements 22s has a cross-sectional shape formed by an arc-shaped convex curve in both the vertical and horizontal directions in order to perform diffuse reflection in the vertical and horizontal directions as described above. Have been. At this time, as for the vertical convex curve of each auxiliary reflecting surface element 22s, as shown in FIG.
The radius of curvature and the inclination angle are set such that the reflected light at the lower end by 1 (α1 = about 2 °) and downward by α2 (α2 = about 40 °) from the horizontal plane. On the other hand, regarding the convex curve in the left-right direction of each auxiliary reflection surface element 22s, the curvature radius is set slightly different for each auxiliary reflection surface element 22s.

FIG. 5 is a diagram showing the direction of reflected light at each position in the vertical direction in each of the auxiliary reflecting surface elements 22s. As shown in the drawing, the auxiliary reflection surface element 22s has a vertical cross-sectional shape formed by a convex curve, so that the reflected light flux toward the road surface immediately before the vehicle becomes dense, and the reflected light flux toward the road surface ahead of the vehicle. The reflected light beam becomes sparser as the distance increases.

FIG. 6 is a graph showing a road surface illuminance distribution on a line (a dashed line shown in FIG. 4) where the vertical plane including the optical axis Ax intersects the road surface in front of the lamp, and a curve I shown by a solid line. (P) is the road surface illuminance distribution of the auxiliary light distribution pattern P, and the curve I (PA) indicated by a two-dot chain line is the road surface illuminance distribution of the additional light distribution pattern PA, and the curve I (P +
PA) is the road surface illuminance distribution obtained by combining the two patterns P and PA.

As described in detail above, in the present embodiment, the boundary B between the reflection surface 16a of the reflector 16 and the upper wall surface 16b extending forward from the upper end edge thereof (ie, at a high position in the lamp), Since a plurality of auxiliary reflection surface elements 22a that diffuse and reflect light from the light source bulb 18 in a vertical direction and a horizontal direction below a horizontal plane are formed, reflected light from each of the auxiliary reflection surface elements 22a is The light can be radiated to the front of the vehicle as downward diffused light (additional light distribution pattern PA) without being blocked by a shade 20 provided near the front of the light source bulb 18 or a vehicle bumper protruding forward from near the lower part of the lamp.

Therefore, in the sub-light distribution pattern P formed by the reflection surface 16a, the road surface immediately before the vehicle where the irradiation light tends to be insufficient can be sufficiently irradiated by the reflected light from the auxiliary reflection surface element 22a.

At this time, the additional light distribution pattern PA irradiates not only the road surface immediately before the vehicle but also a road surface in front thereof (a road surface at a short distance in front of the vehicle) over a relatively wide range. PA and the auxiliary light distribution pattern P are not separated from each other.
Also, the overlapping portion of the PA and the PA does not become extremely brighter than the surrounding portion. Therefore, it is possible to effectively suppress the occurrence of irradiation unevenness on a road surface at a short distance in front of the vehicle, which is very conspicuous even with slight irradiation unevenness.

Since the auxiliary reflecting surface elements 22a are arranged side by side so as to straddle the position above the light source bulb 18 on the left and right sides, uneven reflection due to the diffusely reflected light from these auxiliary reflecting surface elements 22a. A small and relatively large irradiation pattern can be relatively easily formed on a road surface. Further, each of the auxiliary reflection surface elements 22a is connected to the reflection surface 16a.
Are formed at a lateral pitch narrower than the lateral pitch of each of the reflective surface elements 16s constituting the region near the upper edge of the sub-surface, so that fine light distribution control of the grain can be performed by these auxiliary reflective surface elements 22a. In addition, it is possible to more effectively suppress the occurrence of irradiation unevenness on a road surface at a short distance in front of the vehicle. That is, each of the auxiliary reflection surface elements 22a has a cross-sectional shape in the left-right direction set to a convex curve having a slightly different radius of curvature, and the left-right diffusion angle of the reflected light from each of the auxiliary reflection surface elements 22a is Since they are different from each other, it is possible to effectively prevent the occurrence of irradiation unevenness (particularly, light pools formed at the left and right ends of the additional light distribution pattern PA) caused by the irradiation pattern itself formed by the auxiliary reflection surface elements 22a. Can be suppressed.

Further, in the present embodiment, since the vertical sectional shape of each of the auxiliary reflection surface elements 22a is formed by a convex curve, as shown in FIG. Can be distributed more to the road surface immediately before the vehicle than to the road surface at a short distance in front of the vehicle. As a result, as shown by a curve I (PA) in FIG. An illumination pattern in which the brightness gradually decreases from the road surface to the road surface at a short distance in front of the vehicle can be obtained. Therefore, in FIG.
As shown by (P + PA), it is possible to more effectively suppress the occurrence of irradiation unevenness when the additional light distribution pattern PA and the auxiliary light distribution pattern P are superimposed.

In the present embodiment, each of the auxiliary reflecting surface elements 22a is connected to the reflecting surface 16a and the upper wall surface 16a.
Since it is provided at the boundary B with the light source b, the solid angle of use of the reflector with respect to the light from the light source bulb can be increased, whereby the headlight 10 can be made brighter.

The lens 12 in the present embodiment has a so-called inverted slant shape which is inclined so as to be displaced rearward downward, so that
The large-angle downward reflected light from 2s can be emitted to the front of the lamp without being blocked by the lower flange portion of the lens or the like, whereby the road surface immediately before the vehicle can be emitted. The headlight 10 according to the present embodiment includes:
Since it is mounted on a cab-over type truck where the driver's viewpoint is high above the ground and the driver can see up to the road surface just before the vehicle, it is particularly effective to be able to irradiate the road surface just before the vehicle in this way. It is a target.

When a high-intensity and high-power discharge bulb is used as the light source bulb 18 as in this embodiment, the sub-light distribution pattern P formed by the light reflected from the reflection surface 16a is used. Is very bright, and the road surface immediately before the vehicle tends to be relatively dark. Therefore, the additional light distribution pattern PA is formed by the plurality of auxiliary reflection surface elements 22a.
Is particularly effective.

In the above-described embodiment, the case where the vertical cross-sectional shape of each auxiliary reflection surface element 22s is constituted by an arc-shaped convex curve has been described. It may be configured by a combination (or a combination of a convex curve and a concave curve). In such a case, the additional light distribution pattern P
A can be formed with a fine road surface illumination distribution corresponding to the road surface illumination distribution of the auxiliary light distribution pattern P.

[Brief description of the drawings]

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

FIG. 2 is a side sectional view of the headlight.

FIG. 3 is a screen light distribution pattern diagram showing the operation of the embodiment.

FIG. 4 is a road surface light distribution pattern diagram showing the operation of the embodiment.

FIG. 5 is a diagram showing the direction of reflected light at each position in the vertical direction in each auxiliary reflection surface element of the embodiment.

6 is a graph showing a road surface illuminance distribution on a dashed line shown in FIG. 4;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Headlight 12 Lens 14 Body 16 Reflector 16a Reflection surface 16b Upper wall surface 16c Lower wall surface 16s Reflection surface element 18 Light source bulb (discharge bulb) 18a Light emitting part (arc) 20 Shade 22s Auxiliary reflection surface element Ax Optical axis B Boundary part F Focus position I (P) Road surface illumination distribution of auxiliary light distribution pattern I (PA) Road surface illumination distribution of additional light distribution pattern I (P + PA) Composite road surface illumination distribution of auxiliary light distribution pattern and additional light distribution pattern P Secondary light distribution Light pattern PA Additional light distribution pattern

Claims (6)

[Claims] 1. A vehicular headlamp comprising: a light source bulb; and a reflector configured to form a required light distribution pattern by controlling reflection of light from the light source bulb. A reflection surface for forming the light distribution pattern, and an upper wall surface extending forward from an upper end edge of the reflection surface, and a boundary between the reflection surface and the upper wall surface, from the light source bulb. A headlamp for a vehicle, wherein an auxiliary reflection surface element for diffusing and reflecting light in a vertical direction and a horizontal direction below a horizontal plane is formed. 2. The vehicle headlight according to claim 1, wherein a vertical cross-sectional shape of the auxiliary reflection surface element is formed by a convex curve. 3. The device according to claim 1, wherein a plurality of the auxiliary reflection surface elements are juxtaposed so that the auxiliary reflection surface element straddles right and left over the light source bulb along the boundary portion. Headlights for vehicles. 4. At least a region in the vicinity of an upper edge of the reflecting surface is divided into a plurality of reflecting surface elements at a predetermined left-right pitch, and each of the auxiliary reflecting surface elements is arranged at a predetermined pitch from the left-right pitch of each reflecting surface element. 4. The vehicle headlight according to claim 3, wherein the vehicle headlights are arranged side by side at a narrow left-right pitch. 5. A headlight for a vehicle according to claim 1, wherein a lens inclined so as to be displaced rearward downward is provided in front of said reflector. . 6. The light source bulb comprises a discharge bulb.
The vehicle headlight according to any one of claims 1 to 5, wherein: