JPH1040711A - Head lamp for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently suppress glare light in which an upper end portion of a diagonal light distribution pattern forming a diagonal cut line becomes excessively bright in a head lamp for auxiliary lamp light distribution pattern forming providing a discharge bulb. SOLUTION: Inner three reflection face elements 22A2s of nine reflection face elements constituting a reflection face region 22A for diagonal light distribution pattern forming are formed so that reflection light from these reflection face elements 22A2s is more downward than reflection light from outside five reflection face elements 22A1s. Thus, brightness at an upper end portion of a diagonal light distribution pattern is lowered.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle headlamp having a discharge bulb, and more particularly to a headlamp for forming a sub-light distribution pattern.

[0002]

2. Description of the Related Art In recent years, a discharge bulb has been used as a light source of a vehicle headlamp since it can emit high-intensity light.

[0003] In a headlamp having such a discharge bulb, when a sublamp light distribution pattern having an oblique cut line and a horizontal cut line is formed, a wide illumination angle with excellent distant visibility is provided. It is possible to obtain the auxiliary light distribution pattern.

[0004]

However, in this case, there are the following problems.

That is, using a discharge bulb, for example,
When the left side light distribution pattern P as shown in FIG. 8 is formed, since the power of the light source is very large, the upper end PAa 'of the diagonal light distribution pattern PA' forming the diagonal cut line CL1 is formed. There is a problem that it becomes too bright, and it is easy to give glare to a pedestrian on the left sidewalk, an oncoming driver when turning right, and the like.

Further, in this case, since the discharge bulb forms an image whose luminous intensity distribution characteristic is completely different from that of a halogen bulb or the like, the upper end PA of the oblique light distribution pattern PA 'is formed.
There is a problem that a 'is more likely to be brighter.

That is, FIG. 10 is a diagram showing the luminous intensity distribution in the longitudinal direction of the image of the light source when the light from the light source is reflected at a point on the reflector reflecting surface 22 and is irradiated on the front screen. As shown in FIG. 10A, when the light source is a halogen bulb (filament 18a '), the luminous intensity distribution in the longitudinal direction of the image I' of the light source is such that the luminous intensity at both ends thereof gradually decreases. While Figure 10
As shown in (b), when the light source is (the light emitting part (arc) 18a of) the discharge bulb, the luminous intensity distribution in the longitudinal direction of the image I of the light source is such that the luminous intensity at both ends thereof sharply decreases. become.

When the image I having the luminous intensity distribution characteristic in which the luminous intensity at both ends in the longitudinal direction suddenly decreases is deflected or diffused along the oblique cut line CL1 shown in FIG. Light distribution pattern PA '
Is a light distribution pattern of high luminosity up to both ends. The upper end PAa 'of the oblique light distribution pattern PA' becomes very bright, in combination with the fact that the power itself of the discharge bulb is very large.

The present invention has been made in view of such circumstances, and is directed to a headlamp for forming a sublamp light distribution pattern having a discharge bulb, which has an oblique light distribution pattern forming an oblique cut line. It is an object of the present invention to provide a vehicular headlamp capable of effectively suppressing glare light due to an excessively bright upper end portion.

[0010]

According to the present invention, the above object is achieved by providing a luminous intensity reducing means for lowering the luminous intensity at the upper end of the oblique light distribution pattern.

That is, the present invention comprises a discharge bulb and a reflector having a reflecting surface for reflecting light from the discharge bulb forward, and comprises an oblique cut line and a horizontal cut line. In a vehicle headlamp configured to form a sub-light distribution pattern having a line, the vehicle headlamp includes a luminous intensity reducing unit configured to reduce the luminous intensity of an upper end portion of the oblique light distribution pattern forming the oblique cut line. It is characterized by the following.

The specific structure of the "luminous intensity reducing means" is not particularly limited as long as it can reduce the luminous intensity at the upper end of the oblique light distribution pattern.

For example, in a headlamp in which a plurality of reflecting surface elements for forming the oblique light distribution pattern by controlling reflection of light from a discharge bulb are formed on the reflecting surface. As described above, a part of the plurality of reflecting surface elements is formed such that the reflected light from the reflecting surface element is lower than the reflected light from the other reflecting surface elements constituting the plurality of reflecting surface elements. Thereby, the luminous intensity decreasing means can be configured.

As a specific configuration for directing the reflected light downward, the vertical cross-sectional shape of each reflecting surface element forming an oblique light distribution pattern is defined as follows. A configuration in which the parabolic axis is set to have the same focal length and the parabolic axis of some of the reflective surface elements is set downward with respect to the parabolic axis of the other reflective surface element, A configuration in which the direction cross-sectional shape is set to a curved shape in which a portion separated from the parabolic axis upward in the parabolic shape is translated downward and rearward, or a configuration in which these are combined, and further, as described in claim 5 In addition, the vertical cross-sectional shape of each reflective surface element forming an oblique light distribution pattern is set to a parabolic shape, and the vertical cross-sectional shape of the partial reflective surface element is set to the other reflective surface element. Configuration or the like set in the short parabolic focal length than the lower cross section shape can be employed.

In a headlamp, a lens disposed in front of the reflector is provided with a plurality of lens steps for forming a diagonal light distribution pattern by controlling refraction of reflected light from the reflector. As described in Item 6, a part of the plurality of lens steps is formed such that transmitted light from the lens steps is directed downward from transmitted light from other lens steps constituting the plurality of lens steps. By doing so, the luminous intensity decreasing means can be configured.

Further, a shade is provided in the vicinity of the discharge bulb, which is provided with a tip for shielding direct light emitted from the discharge bulb forward and a leg for supporting the tip with a reflector. As described in 7, the shielding piece that shields a part of the light from the discharge bulb toward the reflection surface area for reflecting the light for forming the oblique cut line of the reflector is provided at the base end of the leg of the shade. Thus, the luminous intensity reducing means can be configured.

[0017]

As described above, according to the present invention, the luminous intensity lowering means for lowering the luminous intensity at the upper end of the oblique light distribution pattern forming the oblique cut line is provided. Even when the auxiliary light distribution pattern is formed, it is possible to prevent the upper end portion of the oblique light distribution pattern from becoming too bright beforehand, so that when turning to a pedestrian or an oncoming lane side of the sidewalk on the own lane side. The possibility of giving glare to the oncoming vehicle driver or the like can be reduced.

As described above, according to the present invention, in a headlamp provided with a discharge bulb for forming a sub-lamp light distribution pattern,
It is possible to effectively prevent the upper end portion of the oblique light distribution pattern forming the oblique cut line from becoming too bright and becoming glare light.

Although the specific configuration of the "luminous intensity lowering means" is not particularly limited as described above, as described in claim 2 or claim 6, the reflected light from the reflecting surface element or the lens. If the luminous intensity reducing means is configured by deflecting the transmitted light from the step downward, it is possible to suppress the generation of glare light without any loss of the light flux. At this time, if the downward deflection amount is set to an appropriate value, this can be effectively used as the roadside portion irradiation light.

On the other hand, in the case where the luminous intensity reducing means is constituted by providing a shielding piece at a base end portion of the leg portion of the shade (ie, a portion closest to the reflector), The shielded light is wasted, but by appropriately setting the size, shape, and the like of the shielding piece, the light directed to the reflective surface area that reflects the light that forms the upper end of the oblique light distribution pattern is efficiently shielded. In addition, if this shielding piece is used in combination with the above-described downward deflection by the reflecting surface element or the lens step, fine adjustment in the downward deflection control can be performed. This can be exploited as a means.

[0021]

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 a first embodiment of the present invention, and FIG. 2 is a side sectional view thereof.

As shown in these figures, a headlamp 10 according to the present embodiment is configured such that a reflector 16 having a discharge bulb 18 and a shade 20 mounted in a space formed by a lens 12 and a body 14 is vertically movable. The sub-light distribution pattern P of the left light distribution having an oblique cut line (15 ° cut line) CL1 and a horizontal cut line CL2 as shown in FIG. It is configured to form.

The lens 12 is a transparent lens,
The auxiliary light distribution pattern P is formed by the reflector 16.

That is, the reflecting surface 2 of the reflector 16
Reference numeral 2 designates, as a reference plane, a paraboloid of revolution having the optical axis Ax extending in the front-rear direction as a central axis, and divides the reference plane into a plurality of segments, each of which has a different curvature from the reference plane. It is configured by allocating the reflection surface element 22s. Then, by setting the curvature of each of the reflection surface elements 22s to an appropriate value, based on the light distribution pattern Po of FIG. 3A formed by the reflected light from the reference surface, FIG. ) Is obtained.

The discharge bulb 18 is a metal halide discharge bulb whose optical axis (reference axis) is
6, the light-emitting portion (arc) 18a is attached to the reflector 16 such that the light-emitting portion (arc) 18a is located slightly forward of the focal position F of the paraboloid of revolution, which is the reference surface of the reflector 16. . The above discharge bulb 1
8 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 its lighting. An extension 28 is provided in front of the reflector 16.

The shade 20 has a cup-shaped tip 20a covering the front of the discharge bulb 18, and a tip 20a.
And a semi-cylindrical portion 20b fixed to the reflector 16 at a rear end portion, and extends from the discharge bulb 18 to the lamp by the front end portion 20a. In addition to blocking direct light that goes forward, the semi-cylindrical portion 20b blocks light that goes from the discharge bulb 18 to a region below the reflecting surface 22 of the reflector 16. The oblique cut line CL is formed by the upper edge 20b1 of the right side of the semi-cylindrical portion 20b (the right side toward the front of the lamp, the same applies hereinafter).
1, and the horizontal cut line CL2 is formed by the left upper edge 20b2.

As shown by a two-dot chain line in FIG. 1, a shadow line SL1 of light from the light emitting portion 18a of the discharge bulb 18 is formed on the reflection surface 22 of the reflector 16 by the upper right edge 20b1 and the upper left edge 20b2. And SL2 are formed.

In the auxiliary light distribution pattern P shown in FIG. 3B, the oblique light distribution pattern PA forming the oblique cut line CL1 generally has a reflection surface area 22A shown in FIG.
(In other words, it is formed by the reflected light from the reflective surface area including all the reflective surface elements that intersect with the shadow line SL1.) In the present embodiment, the nine reflective surface elements constituting the reflective surface area 22A are formed in this embodiment. Of which, the outer five reflection surface elements 22A
The oblique light distribution pattern PA is formed by the reflected light from 1 s, and for the three inner reflective surface elements 22A2s, the light from the reflective surface element 22A2s is directed diagonally to the lower left of the oblique cut line CL1 for roadside illumination. A pattern PB is formed.

As shown by the solid line in FIG. 4, which is a cross-sectional view taken along the line VI-VI of FIG. 1, each of the above-mentioned reflecting surface elements 22A2s is larger than the other reflecting surface elements 22A1s shown by the two-dot chain line in the drawing. The upper part is set to have a vertical cross-sectional shape that rises slightly forward (more precisely, a cross-sectional shape in a direction inclined by 15 ° from the vertical direction) so as to reflect light from the camera downward. Specifically, as shown in FIG.
The parabolic axis Ax 'of each of the reflective surface elements 22A2s is set downward with respect to the parabolic axis Ax of the other reflective surface element 22A1s (more precisely, an axis parallel to the optical axis Ax of the reflector 16). Thus, the light distribution pattern for roadside irradiation PB is formed based on the light distribution pattern PBo shown in FIG.

The oblique light distribution pattern PA shown in FIG.
Is formed on the basis of the light distribution pattern of the light distribution pattern PAo shown in FIG. 3A excluding the light distribution pattern PBo. At this time, the five reflection surface elements 22A1s are formed. Most of the reflected light from the light source is used for forming a hot zone (region illuminated brightest) HZ indicated by a two-dot chain line in FIG. Is significantly reduced as compared with the case where the oblique light distribution pattern PA is formed using all the reflection surface elements constituting the reflection surface region 22A as in the related art.

As described above in detail, in the present embodiment, the reflection from the inner three reflection surface elements 22A2s among the nine reflection surface elements constituting the reflection surface area 22A for forming the oblique light distribution pattern PA. The light is reflected from the outer five reflection surface elements 22.
A1s is formed so as to be lower than the reflected light from A1s, thereby lowering the luminous intensity of the upper end PAa of the oblique light distribution pattern PA forming the oblique cut line CL1. In the case where the auxiliary light distribution pattern P is formed by using the above, it is possible to prevent the upper end portion PAa of the oblique light distribution pattern PA from becoming too bright, whereby the pedestrian on the left sidewalk or the right turn can be prevented. In this case, it is possible to reduce the possibility of giving glare to an oncoming vehicle driver or the like.

As described above, according to the present embodiment, in the headlamp for forming the auxiliary light distribution pattern provided with the discharge bulb, the upper end of the oblique light distribution pattern forming the oblique cut line becomes too bright. Glare light can be effectively suppressed.

Moreover, in the present embodiment, the light distribution pattern PB for illuminating the road shoulder is formed by the reflected light from the reflection surface element 22A2s, so that glare light can be generated without any loss of light flux. Not only can it be suppressed, but it is also possible to sufficiently illuminate the road shoulder on the left side in front of the vehicle, whereby early detection of a pedestrian or the like jumping out from the side of the road can be achieved.

In the first embodiment, FIG.
, The parabolic axis Ax ′ of each of the reflective surface elements 22A2s is changed to the parabolic axis A of the other reflective surface element 22A1s.
x, the reflected light from each of the reflective surface elements 22A2s can be reflected by the other reflective surface elements 22A2s.
Although it is configured to reflect downward from the reflected light from A1s, it is also possible to adopt a configuration as shown in FIGS. 9B and 9C instead. FIG. 9B
In the configuration shown in FIG. 5, the vertical cross-sectional shape of each of the reflective surface elements 22A2s is translated downward and slightly rearward from the parabolic shape (vertical cross-sectional shape) of the other reflective surface element 22A1s, and the parabolic axis Ax in the parabolic shape is obtained. Is set in a curved shape at a portion away from the upper surface of the other reflective surface element 22A2s.
The light is reflected downward from the reflected light from A1s. In addition, the configuration shown in FIG. 9C sets the focal length f2 of the parabolic shape (vertical cross section) of each of the reflective surface elements 22A2s to the other reflective surface element 22A1s.
By setting the focal length f1 shorter than the focal length f1 of the parabolic shape (vertical cross section), each of the reflection surface elements 22A2
s is reflected downward from the reflected light from the other reflective surface element 22A1s.

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

FIG. 5 is a view similar to FIG. 4, showing a main part of the vehicle headlamp according to this embodiment.

In the first embodiment, the sub-light distribution pattern P is formed by controlling the reflection light of the reflection surface 22 of the reflector 16, and the lens 12 disposed in front of the reflector 16 is transparent. In the present embodiment, the reflector 16 ′ has a reflecting surface 22 ′ formed of a paraboloid of revolution, while the reflector 16 ′ is configured as a lens, and is formed by a plurality of lens steps formed on the inner surface of the lens 12 ′. The sub-light distribution pattern P is formed by controlling the refraction of the parallel reflected light from the reflection surface 22 '. Then, among a plurality of lens steps forming the oblique light distribution pattern PA, three lens steps 12s ′ near the optical axis Ax of the reflector 16 are transmitted through the lens steps 12s ′ (shown by solid lines). The plurality of lens steps forming the oblique light distribution pattern PA are formed in a downwardly deflecting prism shape so as to be lower than transmitted light (indicated by a two-dot chain line) from other lens steps.

By forming such a lens step 12s', the same function and effect as in the first embodiment can be obtained.

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

FIG. 6 is a perspective view showing a main part of the vehicle headlamp according to the present embodiment.

In the present embodiment, similar to the first embodiment, the sub-light distribution pattern P is formed by controlling the reflected light of the reflection surface 22 of the reflector 16, but in the present embodiment, The three inner reflective surface elements 22A2s' constituting the reflective surface area 22A do not reflect the light from the discharge bulb 18 downward to the five outer reflective surface elements 22A1s. Region 22
By the reflected light from all the reflective surface elements constituting A,
An oblique light distribution pattern PA as shown in FIG. 7 is formed.

In this embodiment, a shielding piece 30 is provided at the base end of the semi-cylindrical portion 20b of the shade 20. The shielding piece 30 is formed integrally with the semi-cylindrical portion 20b so as to extend upward from the right upper edge 20b1 of the semi-cylindrical portion 20b in a rectangular shape. By providing the shielding piece 30 and raising the base end portion 20b1a of the right upper edge 20b1 by one step, a shadow line SL1a is formed at a position higher than the shadow line SL1 forming the oblique cut line CL1.
Three reflective surface elements 22A2s' inside reflective surface region 22A
, Light from the light emitting portion 18a of the discharge bulb 18 is prevented from being incident to a position above the shadow line SL1. As a result, the oblique light distribution pattern PA shown in FIG.
The light distribution pattern lacks the upper end PAa 'as compared to the oblique light distribution pattern PA' (shown by a dashed line) formed when the shielding piece 30 is not provided.

As described above, also in the present embodiment, it is possible to effectively prevent the upper end portion of the oblique light distribution pattern from becoming too bright and becoming glare light.

Although the light shielded by the shielding piece 30 is wasted, the amount of light shielding can be adjusted relatively accurately by appropriately setting the size, shape, and the like of the shielding piece 30. Thus, the optimum position and shape of the upper edge of the light distribution pattern PA can be set by trial and error.

As in the third embodiment, the shielding piece 3
Instead of using only 0 to suppress glare light, if this is used together with the downward deflection by the reflecting surface element or the lens step of the first or second embodiment, the shielding piece 30 can be used as a fine adjustment means in the downward deflection control. Can be utilized.

[Brief description of the drawings]

FIG. 1 is a front view showing a vehicle headlamp according to a first 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 first embodiment.

FIG. 4 is a sectional view taken along the line IV-IV in FIG.

FIG. 5 is a view similar to FIG. 4, showing a main part of a vehicle headlamp according to a second embodiment of the present invention;

FIG. 6 is a perspective view showing a main part of a vehicle headlamp according to a third embodiment of the present invention.

FIG. 7 is a screen light distribution pattern diagram showing the operation of the third embodiment.

FIG. 8 is a screen light distribution pattern diagram showing the operation of a conventional example.

FIG. 9A is a diagram showing a specific shape of a vertical cross-sectional shape of a reflection surface element, which is a main part of the vehicle headlamp according to the first embodiment, and FIG. 9B is a diagram showing a modification thereof. , (C)

FIG. 10 is a diagram showing a difference in a luminous intensity distribution characteristic in a longitudinal direction of an image of the reflected light between a case where a halogen bulb is used as a light source and a case where a discharge bulb is used.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Headlight 12, 12 'Lens 12s' Lens step (light intensity reduction means) 14 Body 16, 16 'Reflector 18 Discharge bulb 18a Light emitting part (arc) 20 Shade 20b Semi-cylindrical part (leg) 22, 22' Reflecting surface 22s, 22A1s Reflecting surface element 22sA2 Reflecting surface element (luminous intensity reducing means) 30 Shielding piece (luminous intensity decreasing means) Ax Optical axis CL1 Diagonal cut line CL2 Horizontal cut line F Focus position HZ Hot zone P Secondary light distribution pattern PA Diagonal light distribution Pattern PB Light distribution pattern for roadside irradiation PAa Upper end SL1, SL2, SL1a Shadow line

Claims (7)

[Claims] 1. A light distribution pattern comprising: a discharge bulb; and a reflector having a reflection surface for reflecting light from the discharge bulb forward, so as to form a sub lamp light distribution pattern having an oblique cut line and a horizontal cut line. The vehicle headlamp according to the present invention, further comprising a luminous intensity reducing unit configured to reduce the luminous intensity at the upper end of the oblique light distribution pattern forming the oblique cut line. 2. A plurality of reflecting surface elements for controlling the reflection of light from the discharge bulb to form the oblique light distribution pattern are formed on the reflecting surface, and wherein the luminous intensity reducing means includes a plurality of reflecting devices. Part of the surface element,
The light source device according to claim 1, wherein the reflected light from the reflective surface element is formed to be lower than the reflected light from the other reflective surface elements constituting the plurality of reflective surface elements. 1. The vehicle headlight according to 1. 3. The vertical cross-sectional shape of each reflecting surface element forming the oblique light distribution pattern is set to a parabolic shape having the same focal length, and the parabolic axis of the some reflecting surface elements is: 3. The vehicle headlight according to claim 2, wherein the headlamp is set downward with respect to the parabolic axis of the other reflection surface element. 4. The vertical cross-sectional shape of each of the reflecting surface elements forming the oblique light distribution pattern is set to be a parabolic shape having the same focal length, and the vertical cross-sectional shape of the some of the reflecting surface elements is provided. 4. The vehicle headlight according to claim 2, wherein in the parabolic shape, a portion of the parabolic shape, which is separated from the parabolic axis in an upward direction, is translated downward and rearward in a curved shape. 5. The vertical cross-sectional shape of each of the reflecting surface elements forming the oblique light distribution pattern is set to a parabolic shape, and the vertical cross-sectional shape of some of the reflecting surface elements is other than the above. 3. A parabolic shape having a shorter focal length than the vertical cross-sectional shape of the reflecting surface element of claim 1.
The vehicle headlight described. 6. A lens disposed in front of the reflector is provided with a plurality of lens steps for controlling the refraction of light reflected from the reflector to form the oblique light distribution pattern. , A part of the plurality of lens steps is formed such that transmitted light from the lens steps is directed downward from transmitted light from other lens steps constituting the plurality of lens steps. The vehicle headlight according to claim 1, wherein: 7. A shade is provided in the vicinity of the discharge bulb, the shade including a tip for shielding direct light emitted from the discharge bulb forward, and a leg for supporting the tip with the reflector. The luminous intensity reducing means, the shade of the leg portion of the shade, so as to block a part of the light from the discharge bulb toward the reflective surface area reflecting the light for forming the oblique cut line in the reflector. The vehicle headlight according to any one of claims 1 to 6, comprising a shielding piece provided at a base end portion.