JPS62291801A - Head lamp for vehicle - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The vehicle headlamp of the present invention will be explained according to the following items.

A. Field of industrial application B1 Overview of the invention C0 Prior art and its problems 1 Means for solving the problem E. Examples [Figs. 1 to 4] 80 Reflector [Figs. 2, FIG. 4]b, light source [1st
Figures, Figures 2, and 4] c. l Shielding screen [Figures 1, 2, and 4] d. Function of shielding screen [Figure 2 d-1. Light from a high-pressure metal vapor discharge lamp [Fig. 2 (A)] d-2, Light from an incandescent lamp [Fig. 2 (B) e, Projection lens [Fig. 1, Fig. 2, Fig. 4] f. Function of projection lens [FIGS. 1 and 3] F3 Effects of the invention (A. Field of industrial application) The present invention relates to a novel headlamp for a vehicle. Specifically, by using a high-output high-pressure metal vapor discharge lamp as the main light source, the forward heat radiation ability is increased, and the discharge state of the high-pressure metal vapor discharge lamp used as the main light source is stable and the predetermined output is achieved. The incandescent light source is turned on while the discharge condition of the main light source is unstable. When the temperature drops below, the high-pressure metal vapor discharge lamp is turned off and the incandescent light bulb is turned on so as not to interfere with the running of the vehicle. The present invention aims to provide a new vehicular headlamp that can be miniaturized and provide stable light distribution by adding innovations to the vehicular headlamp.

(B. Summary of the Invention) The vehicle headlamp of the present invention uses a reflector having a spheroidal reflecting surface, and a high-pressure metal vapor discharge lamp is placed at approximately one focal point of the reflector. An incandescent light bulb is placed at approximately the other focal point of the reflector, and until the discharge condition of the high-pressure metal vapor discharge lamp becomes stable, or when the high-pressure metal vapor discharge lamp reaches the end of its life, the incandescent lamp is By lighting the bulb, it is possible to compensate for the lack of output while the discharge condition is unstable or to replace a high-pressure metal vapor discharge lamp that has reached the end of its life. A desired light distribution pattern is obtained by a shielding screen placed in front of the light source and a projection lens placed in front of the shielding screen.

(C. Prior art and its problems) For vehicles 1. For example, the use of discharge lamps for automobile headlights has been often discussed for a long time, but has never been realized. Lamp light sources are limited to light sources that are close to point sources because their light distribution characteristics require optical control such as considerable light convergence and contrast ratio in passing beams. Therefore, if this is a discharge lamp, it is limited to a short arc discharge lamp.

In addition, short arc discharge lamps are required to have high efficiency, and those meeting these conditions are limited to high-pressure metal vapor discharge lamps such as mercury lamps, sodium lamps, and metal halide lamps.

These discharge lamps project the desired luminous flux only in the state of high-pressure metal vapor, so when initially lighting and relighting,
It takes a considerable amount of time to achieve the desired illumination level, which is extremely inconvenient and a safety issue compared to headlamps that utilize incandescent bulbs.

Also, even if these discharge lamps deteriorate and their luminous flux decreases considerably, do they immediately turn off? However, this is extremely dangerous as the vehicle will be driven with its functionality degraded as a headlight.

Furthermore, at the end of its life, the discharge becomes unstable due to a decrease in discharge capacity, causing flickering, extinguishing, and difficulty in re-lighting.The lamp reaches its end of life after a considerable period of unstable conditions, such as flickering, extinguishing, and difficulty in re-lighting. be.

The above-mentioned characteristics of discharge lamps are a fatal defect in automobile headlights, and are the biggest reason why headlights using discharge lamps have not been realized in the past.

(D. Means for Solving the Problems) The present invention solves the above-mentioned problems and makes it possible to use a high-pressure metal vapor discharge lamp as a light source for vehicle headlamps. A high-pressure metal vapor discharge lamp is placed at one focus of a reflector having a reflective surface, an incandescent light bulb is placed at the other focus, and a shielding screen is placed near the outer focus of the elliptical reflective surface and in front of the light source placed there. In addition, a projection lens is placed in front of the shielding screen.

Therefore, according to the vehicle headlamp of the present invention, when the discharge state of the high-pressure metal vapor discharge lamp is not stable, such as at the beginning of lighting or at the end of its life, the incandescent lamp is turned on to compensate for the lack of output, and This solves the above-mentioned problems with high-pressure metal vapor discharge lamps by making flickering less noticeable.

(E. Embodiment) [FIGS. 1 to 4] Details of the vehicle headlamp of the present invention will be described below according to the illustrated embodiment.

(a, Reflector) [Figure 1, Figure 2, Figure 4 Figure 1 is a reflector, which has an elliptical reflective surface in the shape of a spheroid, and one end in the long sleeve direction is an opening 2. .

Of the two focal points of the elliptical reflective surface, the focal point 3 closer to the frontage 2 is called the outer focal point, and the focal point 4 farther from the opening 2 is called the inner focal point.

(b, Light source) [Figures 1, 2, and 4] 5 is a high-pressure metal vapor discharge lamp used as a light source in the vehicle headlamp of the present invention; for example, a metal halide lamp is used. Ru. And this high pressure metal vapor discharge lamp 5
The discharge part is located at the inner focal point 4 of the reflecting mirror 1.

6 is an incandescent light bulb used as another light source,
For example, halogen bulbs are used. A light emitting part, for example a filament, of this incandescent lamp 6 is positioned at the outer focal point 3 of the reflecting mirror 1.

(c, shielding screen) [Figures 1, 2, 4] 7 is a shielding screen, and its upper edge 7a is connected to the reflecting mirror 1.
is located close to the optical axis xx (rotation axis of the ellipsoid of revolution), and is located slightly forward of the outer focal point 3 of the reflecting mirror in the optical axis XX direction.

(d. Function of shielding screen) [FIG. 2] The light emitted from each of the light sources 5 and 6 and reflected by the reflecting mirror 1 is irradiated from the opening 2 as follows.

(d-1, light of high-pressure metal vapor discharge lamp) [Figure 2 (A
) The path of light from the high-pressure metal vapor discharge lamp 5 is shown in Figure 2 (A
).

Of the light emitted from the high-pressure metal vapor discharge lamp 5 and reflected by the reflector 1, the light 1ts, JLs, ... reflected by the road half of the reflector 1 is directed downward after being focused at the outer focal point 3 Proceed at an angle of Therefore, these lights λ5,A
5,... are slightly in front of the outer focal point 3 and the upper edge 7a is located at X-
The light is blocked by the shielding screen 7 which is in contact with X from below, and is prevented from exiting from the opening 2.

Light J emitted from the high-pressure metal vapor discharge lamp 5 and reflected by approximately the lower half of the reflecting mirror 1: L5', ILa', .
are focused at the outer focal point 3 and then proceed at an upward angle. Therefore, these lights ft*', 1s', . . . are intercepted by the shielding screen 7 located below the optical axis XX. Almost all of the light is emitted from the aperture 2 with almost no interruption.

(d-2, Light from an incandescent bulb) [Figure 2 (B)] The path of light from an incandescent bulb will be explained with reference to Figure 2 (B).

Of the light emitted from the incandescent bulb 6 and reflected by the reflector 1, the light J! is reflected by the road half of the reflector 1! s, J2
g, . Therefore, these lights U,...
Almost all of X, . . . are emitted from the opening 2 without being blocked by the shielding screen 7.

The light 16', ia', . After being illuminated, it moves at a downward angle.

Therefore, most of the radiation is blocked by the shielding screen 7 from being emitted.

(e, Projection Lens) [FIGS. 1, 2, 4] A projection lens 8 is formed in the shape of a convex lens, and is disposed in front of the shielding screen 7. A focal point 9 of the projection lens 8 located on the reflecting mirror 1 side is located on the optical path axis xx of the reflecting mirror 1 and slightly in front of the shielding screen 7.

(f. Function of the projection lens) [Figures 1 and 3] Therefore, the image of the shielding screen 7 located outside the focal point 9 of the projection lens 8 is not visible to the projection screen placed in front of the projection lens 8. It will be projected as a real image with the top, bottom, left and right sides reversed.

Therefore, if the upper edge 7a of the shielding screen 7 is made to be an inclined edge downward to the right from the center (point corresponding to the optical axis x-x) (toward the projection screen), the projection screen will have a third As shown in the figure, a light distribution 10 that rises to the left is obtained.

In FIG. 3, V-V is a vertical line, )1-)( is a horizontal line, and the point where the two intersect is located on the extension of the optical axis X-X of the reflecting mirror 1. Also, 7a ' is a line corresponding to the upper edge 7a of the projected image of the shielding screen 7, and the point 11 is the point where !II of the light emitted from the high-pressure metal vapor discharge lamp 5 reaches the projection screen. 12
is the point at which the light 112 emitted from the high-pressure metal vapor discharge lamp 5 and traveling along the optical axis x-x reaches the projection screen;
Point 13 is the light l emitted from the high-pressure metal vapor discharge lamp 5.
I, indicates the point that would reach the projection screen if it were not blocked by the shielding screen 7.

(F. Effects of the Invention) As is clear from the above description, the vehicle headlamp of the present invention is a vehicle headlamp in which two light sources are arranged in one reflecting mirror, has an elliptical reflective surface with two focal points, a high-pressure metal vapor discharge lamp as one light source is placed at one focal point of the elliptical reflective surface, and an incandescent lamp as the other light source is placed at the other focal point of the elliptical reflective surface. The present invention is characterized in that a shielding screen is provided in front of the light source located near the outer focal point of the elliptical reflective surface and at ε thereof, and a projection lens is provided in front of the shielding screen.

Therefore, according to the vehicle headlamp of the present invention, when the discharge state of the high-pressure metal vapor discharge lamp is not stable, such as at the beginning of lighting or at the end of its life, the incandescent lamp is turned on to compensate for the lack of output, and This solves the problems of conventional high-pressure metal vapor discharge lamps by making flickering less noticeable.

Furthermore, as shown in the embodiment, by making the reflecting mirror deep and providing a shielding screen, the high-pressure metal vapor discharge lamp is effectively kept warm and the discharge efficiency is good. Although an incandescent light bulb may be placed at the inner focus of the mirror and a high-pressure metal vapor discharge lamp placed at the outer focus, the light source placed at the inner focus has a higher luminous efficiency and is therefore the main light source. It is preferable to place the high-pressure metal vapor discharge lamp at the inner focus.

[Brief explanation of drawings]

The drawing shows an example of the implementation of the vehicle headlamp of the present invention.
Figure 1 is a vertical cross-sectional view, Figure 2 is a vertical cross-sectional view showing the locus of reflected light, and Figure (A) shows when the high-pressure metal vapor discharge lamp is lit.
B) The figures show the state when the incandescent lamp is on, FIG. 3 is a diagram showing the light distribution pattern projected on the projection screen in front of the vehicle headlamp, and FIG. 4 is a schematic perspective view. Explanation of symbols 1...Reflector, 3...Other focus, 4...One focus, 5...High pressure metal vapor discharge lamp, 6...Incandescent light bulb, 7...Shielding screen, 8... Projection lens light distribution lzu turn diagram Figure 3

Claims (1)

[Claims] A vehicle headlamp in which two light sources are arranged in one reflector, wherein the reflector has an elliptical reflective surface with two focal points, and a high-pressure metal vapor discharge lamp is used as one light source in the elliptical reflector. An incandescent light bulb is placed at one focal point of the surface and an incandescent lamp as the other light source is placed at the other focal point of the elliptical reflecting surface, and a shielding screen is provided near the outer focal point of the elliptical reflecting surface and in front of the light source placed there. , a vehicle headlamp characterized in that a projection lens is provided in front of the shielding screen.