JPH0418404B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a headlamp for use in automobiles and the like, and particularly to a vehicular headlamp equipped with a parabolic cylindrical reflector.

[Conventional technology]

Automotive headlamps with a large front lens inclination angle (slant angle) may use a transparent lens and form light distribution with a parabolic cylindrical reflector. An example of a reflector in that case (Tokugan Showa)
59-269178) is shown in Figure 9.

In FIG. 9, reference numeral 1 denotes a rectangular composite reflecting mirror exhibiting a paraboloidal surface as a whole, and a front lens 2 is attached to the front side thereof.

The reflecting surface of the composite reflecting mirror 1 is divided into a plurality of parabolic cylindrical reflecting sections in the vertical direction when viewed from the front, and the sections are divided at the mounting position 3 of the bulb or light source.
It is formed symmetrically around the center. In the case of the illustrated embodiment, the division is divided into eight parts, and each of the parabolic cylindrical reflection parts 1-1 to 1-
It is labeled as 8. The focal length of each of these parabolic cylindrical reflecting portions is gradually increased from the center side toward the side surface side, and each focal length line is set to intersect at one point. By increasing the focal length of each parabolic cylindrical reflection section in this way, the reflected light spreads in the horizontal direction, and the entire reflecting mirror has a light distribution pattern as shown in Figure 10, for example. . As is clear from this figure, the spread on both sides reaches approximately ±30°, which is ideal.

[Problem that the invention seeks to solve]

However, if the light distribution is formed by diffusing light only with a parabolic cylindrical reflector, the light distribution will be uneven compared to the light distribution formed by diffusing spot reflected light with a lens. easy to become The reason is that the left and right diffused light generated by the parabolic cylinder surface becomes diffused light with a uniform luminous intensity distribution, so when the light is distributed and overlapped, the part of the road surface where the light overlaps becomes bright, and the area near it becomes dark. This is because the light distribution becomes as follows.

In order to prevent the above phenomenon, it is possible to blur the light by placing a diffuser lens in front of the parabolic cylindrical reflector, but since the light that passes through the lens is made up of multiple overlapping diffused rays, On the contrary, unevenness becomes noticeable due to the diffusion caused by the lens.

[Means for solving problems]

A light source using an H4 bulb or a similar filament type bulb, a front lens with a diffusion cut on the entire surface or a part, and multiple paraboloids of revolution.
In a vehicle headlamp consisting of a reflecting section that is a combination of parabolic cylindrical surfaces, the reflecting section is divided into four parts in the vertical direction, and the upper three stages each have a vertical direction that passes through the light source when viewed from the front. It is divided into 8 to 12 parts symmetrically with respect to the central axis, and each of the divided reflection areas has the same focal position in the left-right direction from the central axis for each stage, and the focal length increases as the focal length goes outward from the center. The upper and lower cross sections expanded to become larger are parabolas,
The left and right cross sections are straight lines, and the light from the light source at or near the focal point is made into nearly parallel rays in the vertical direction and diffused rays in the left and right directions according to the width of the surface. The second and third stages each have the same focus provided on the left and right sides further outside of these parabolic cylinder surfaces, and are composed of paraboloids of revolution having the same central axis. The focal line of the object plane intersects with the focal point of the paraboloid of revolution, and the boundaries dividing each reflection area into left and right sides in each stage are formed so that each reflection surface is continuous, and the lower stage is A composite reflector with a reflecting part of a paraboloid of revolution, which has the same center axis as the paraboloids of rotation in the second and third stages, and whose focal point is closer to the reflector than the focal position of the upper three reflecting parts. It is characterized by being prepared.

〔Example〕

Hereinafter, the present invention will be explained in detail based on illustrated embodiments.

1 to 8A and 8B show an embodiment of the present invention, in which 10 is a composite reflector that combines a parabolic cylindrical reflection section and a paraboloid of rotation reflection section, and 20 is a
H4 bulb (or similar filament type bulb), 30 is the front lens.

The reflector 10 is divided into four parts in the vertical direction, and each of the upper three stages is divided into 8 to 10 parts in the left and right direction.
It is divided into areas (up to 12 areas possible). The horizontal division is symmetrical with respect to the central axis in the vertical direction passing through the light source when viewed from the front. The horizontal division is symmetrical about the light source. Area 11-1
~11-11 is a parabolic cylinder surface, areas 12-1, 12-
2 and 13 are paraboloids of revolution, and in the figure, A and B are added to the end to distinguish between left and right.

A parabolic cylindrical surface is a surface whose vertical cross section is a parabola and the horizontal cross section is a straight line, and the light from the light source at or near the focal point is transformed into approximately parallel rays in the vertical direction.
It is reflected in the left-right direction as a diffused beam according to the width of the surface.

The paraboloids of revolution 12-1, 12-2 and the parabolic cylindrical surfaces 11-1 to 11-11 are used to adjust the light distribution pattern of the passing beam, and the paraboloid of revolution 13 is used exclusively for the traveling beam to adjust the central luminous intensity. used to raise. The focal lines of the parabolic cylinder surfaces 11-1 to 11-11 are paraboloids of rotation 12-1 and 12-1 having the same focal point.
It intersects with the focus of 2.

The H4 light bulb 20 is mounted tilted vertically so as to form a horizontal light distribution.

Further, the lens 30 has a slant angle of 0 to
The angle shall be 60°. This lens 30 has a vertical width of
When set to 100%, 30 to 50% of the area from the top is defined as the a-zone 31, and is made of an uncut lens or a diffusing prism with a left-right diffusion of 2° or less. The b zone 32 below this a zone 31 occupies 10 to 40% of the area, and the lens cut pitch (left and right width of the cut) is 3 mm or less, and the left and right diffusion is 1 to 5 degrees. The lowermost c zone 33 is provided with a normal diffusion lens cut.

Note that the parabolic cylinder surface is formed as follows.
That is, as shown in FIGS. 2 and 3, first, the double-sided angle θ ₃ is determined so that the light incident from the focal point Z at an incident angle φ ₁ has a designed left-right diffusion angle θ ₁ . P is the normal to the paraboloid surface, and l is the optical axis (rotation center axis of the paraboloid of revolution). Next, from the design left-right angle θ ₂ in the opposite direction, the incident angle φ ₂ that can be reflected at the parabolic cylinder surface angle θ ₃ is determined, and the width α of the parabolic cylinder surface is determined.

This is developed from the central axis in the vertical direction passing through the light source, and the reflecting surfaces are determined so that each reflecting surface is continuous in the left and right direction and there is no step at the boundary between each reflecting surface. The focal length is determined as F ₁ on the central axis in the vertical direction passing through the optical axis, and then F ₂ is determined based on the distance between the focal point z and the parabolic cylinder surface as the surface is formed. _F1 ,
F ₂ has a relationship of F ₂ >F ₁ . The central axis in the vertical direction passing through this light source is the same as the central axis of the other paraboloids of rotation, and the central axis of each parabolic cylinder surface changes depending on P.

The dimensional relationships of the above structure are shown in FIGS. 4 to 7.

The reflected light patterns obtained by the composite reflector that combines the parabolic cylindrical reflection section and the paraboloid of revolution reflection section are as shown in FIGS. 8A and 8B.
Figure 8A shows the case of a running beam, and Figure 8B shows the case of a passing beam.The pattern formation of the passing beam is performed on parabolic cylinder surfaces 11-1 to 11-11, and is used in areas where long-distance road visibility is required. is a paraboloid of revolution 12
-1, 12-2 is a light distribution pattern in which spot light is irradiated.

Further, in the case of a traveling beam, a hot zone is formed by the paraboloid of revolution 13, thereby improving long-distance visibility.

Note that although the above description is about horizontal pattern light distribution, it can be similarly implemented in the case of asymmetric pattern light distribution such as ECE light distribution and SAE light distribution.

〔Effect of the invention〕

As described above, according to the present invention, a composite reflector is used in which parabolic cylinder surfaces are combined not only in the horizontal direction but also in the vertical direction, and a paraboloid of revolution is also combined, making it easy to adjust the light distribution. Along with becoming
It becomes possible to increase the amount of overlap of reflected light, and it is possible to significantly reduce unevenness in light distribution. Moreover, the diffusion correction by the lens only needs to be small enough to eliminate unevenness, and even with a headlamp with a lens slant angle of 30 degrees or more, light distribution without sagging can be obtained. Furthermore, since a lens cut-out lens was used, it has the advantage of being able to emphasize the vehicle body design line.

[Brief explanation of drawings]

FIG. 1 is a configuration explanatory diagram showing one embodiment of a vehicle headlamp according to the present invention, and FIG. 2 is a cross-sectional view for explaining the configuration of a parabolic cylindrical reflection part of a composite reflector in the same embodiment. Fig. 3 is a sectional view taken along the - line in Fig. 2, Fig. 4 is a front view showing the dimensional relationship of the composite reflector, Fig. 5 is a sectional view thereof, and Fig. 6 is a sectional view taken along the - line in Fig. 4. 7 is a sectional view taken along the line - in FIG. 4, and FIGS. 8A and B are reflected light patterns of the same example.
FIG. 9 and FIG. 10 are explanatory diagrams of a configuration and light distribution pattern showing a conventional example. 10...Composite reflector, 11-1, 11-1
1... Parabolic cylinder surface, 12-1, 12-2 and 13... Paraboloid of revolution, 20... H4 light bulb, 30... Front lens,
31... Lens cut A zone, 32... Lens cut B zone, 33... Lens cut C zone.

Claims (1)

[Claims] 1. A light source using an H4 light bulb or a filament-type light bulb similar to this, a front lens with a diffusion cut on the entire surface or a part thereof, and a plurality of paraboloids of rotation and parabolic cylinder surfaces. In a vehicle headlamp consisting of a combination of reflective parts, the reflective part is divided into four parts in the vertical direction, and the upper three stages are each divided into four parts with respect to the central axis in the vertical direction passing through the light source when viewed from the front. , is divided symmetrically into 8 to 12 parts, and each divided reflection area is expanded at the same focal position in the left and right direction from the central axis for each stage, with the focal length increasing as it goes outward from the center. The upper and lower cross-sections are parabolic, and the horizontal and horizontal cross-sections are straight lines, and the light from the light source at or near the focal point is a plurality of rays that are almost parallel in the vertical direction and diffused in the horizontal direction according to the width of the surface. It consists of an object cylindrical surface and paraboloids of rotation located on the left and right sides of the parabolic cylindrical surfaces on the second and third rows from the top, each having the same focal point and the same central axis. The focal lines of the plurality of parabolic cylindrical surfaces intersect with the focal point of the paraboloid of revolution, and the boundaries dividing each reflective area in each stage into left and right sides are such that each reflective surface is continuous. The lower one has the same central axis as the paraboloids of rotation in the second and third stages, and the focal point is closer to the reflector than the focal position of the upper three reflecting parts. A vehicle headlamp characterized by comprising a composite reflector as a reflecting part.