JPS62195801A - Head lamp for automobile - 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] [Industrial application field] The present invention relates to a headlamp for an automobile.

[Prior art]

Figure 8 shows an example of a conventional automobile headlamp.
8) is a front view, and FIG. 8(B) is a sectional view taken along line B-B.

A light source bulb 2 is installed near the focal point f of the paraboloid of revolution reflecting mirror 5.

Light incident from the light source bulb 2 to the paraboloid of revolution reflector 5 as shown by arrows a and b is reflected parallel to the optical axis Z-Z as shown by arrows c and d, and is modulated by the front lens 6 to obtain the desired light. A light distribution pattern is formed.

However, the light emitted toward the outside of the paraboloid of revolution reflector 5 as shown by the arrow e, and the light that enters the vertical wall portion 7 are reflected as shown by the arrow g and become ineffective. In this way, the effective utilization rate of the luminous flux emitted from the light source bulb 2 is low.

2. Description of the Related Art Projector type headlamps are known because the front lens of the headlamp is made small and its shape is small compared to the luminous intensity of the headlamp. FIG. 9 is a plan view schematically depicting an example of a projector type headlamp, FIG. 10 is a side view, and FIG. 11 is a front view.

1 is a concave mirror, and F is its focal point. The light source bulb 2 is provided so that the filament is located near the focal point F shown in the figure.

A convex lens 3 is provided to share the optical axis Z with the concave mirror 1 described above.

9 indicates the meridional image plane of the convex lens 3, and the light emitted from the light source and reflected by the concave mirror 1 is incident on this meridional image plane.

The above incident light is modulated by the convex lens 3 and is directed forward (
9 and 10).

When a screen is provided near the meridional image plane and the light distribution pattern is shown as an isoluminance curve, it becomes as shown in FIG. 12. H-H is a horizontal line on the screen, and V-V is also a vertical line.

As shown in FIGS. 9 to 11, a shade 4 having an edge along the meridional image plane is provided. For details, please refer to the 11th
As shown in the figure, a cut line 4a is formed so as to recede from the meridional image plane 1-j. FIG. 12 shows how the above-described light distribution pattern and the shade 4 overlap. As shown in FIG. 12, the upper half of the light beam passes through. Although most of the lower half is blocked, light is allowed to pass through the portion corresponding to the cut line 4a.

As the partially covered light beams as described above are focused on the meridional image planes ij and intersect with each other, the light beams projected in front of the headlight have a pattern that is an inversion of the one shown in Fig. 12. form. FIG. 13 is an explanatory diagram showing the general shape of a light projection pattern using isoluminance curves on a screen provided in front of the headlamp.

[Problem that the invention seeks to solve]

As shown in Figure 12 above, 174 of the luminous flux
Since the above portion is covered by the shade 4, the effective utilization rate of the luminous flux is not very high in the projector headlight of this example as well.

The present invention has been made in view of the above-mentioned circumstances, and it is an object of the present invention to provide a headlamp for an automobile that has a high effective utilization rate of luminous flux.

[Means for solving problems]

In order to achieve the above object, the automobile headlamp of the present invention has the following features:
In addition to providing a light source bulb near the focal point of the reflector,
In the vehicle headlamp in which a lens is provided in front of the reflector, (i) the area including the center of the reflector is:
(ii) the upper and lower regions of the paraboloid of revolution area are configured in the shape of an ellipsoid of revolution with a first focus near the light source bulb; and (iii) a shade is provided near the second focal point of the spheroidal reflective surface, and (iv) the lens has a convex lens portion near the center thereof that focuses near the second focal point. It is characterized by what it did. [Function] In the automobile headlamp constructed as described above, the light incident on the paraboloid of revolution reflection surface is reflected parallel to the optical axis, similar to the conventional example shown in FIG. The light is controlled and projected by the front lens.

In addition, the light emitted above or below the paraboloid of revolution reflection surface is reflected by the spheroid reflection surface, condensed near the second focal point, and then dimmed by the shade. Light is projected through the convex lens section. In this way, light that was previously ineffective is effectively utilized.

〔Example〕

FIG. 2 is a front view of one embodiment of the automobile headlamp of the present invention.

FIG. 1 is a cross-sectional side view depicting the I-■ cross section, and FIG. 3 is a plan view.

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

Reference numeral 8 denotes a reflector, whose central portion 8a is configured in the shape of a paraboloid of revolution, and a light source bulb 2 is provided near its focal point F.

Above and below the paraboloid of revolution reflecting surface 8a at the center, an ellipsoid of revolution reflecting surface 8b is provided.

The spheroidal reflecting surface 8b is set so that its first focal point coincides with the point F1. And its second focus F
A shade 9 is provided near 2.

The front lens 10 is a prism lens, and has a convex lens 10a integrated near its center. This convex lens 10a
is constructed so that its focal point approximately coincides with the aforementioned point F2.

The light incident on the paraboloid of revolution reflection surface 8a as indicated by the arrow ffi in FIG.
The light is reflected in parallel with the front lens 10 and is modulated by the front lens 10 to form a light distribution pattern as shown in FIG.

In addition, the light incident on the spheroidal surface as shown by arrows s and t is focused at the second focal point F2 as shown by arrows u and v, is modulated by the shade 9, and is converted into a nearly parallel beam by the convex lens 10a, and is directed forward. The light is projected toward the left side in FIG. 1, forming a light distribution pattern as shown in FIG. The light distribution portion shown in FIG. 6 is formed by a luminous flux that is ineffective in the conventional example shown in FIG.

The light distribution pattern of the entire headlamp of this embodiment is as shown in FIG. 7, which is a combination of the pattern in FIG. 5 and the pattern in FIG. 6.

〔Effect of the invention〕

As described in detail above, when the automobile headlamp of the present invention is applied, the effective utilization rate of the luminous flux emitted from the light source bulb can be significantly increased.

[Brief explanation of drawings]

1 to 3 show one embodiment of an automobile headlamp according to the present invention, in which FIG. 1 is a sectional view taken along line II in FIG. 2, FIG. 2 is a front view, and FIG. 3 is a plan view. Figures 4 and 4 are first sectional views from ■ to ■. FIGS. 5 to 7 are charts depicting light distribution patterns for explaining the optical characteristics of the above embodiment. Figure 8 shows an example of a conventional automobile headlamp;
8) is a front view, and FIG. 8(B) is a sectional view taken along line B-B. 9 to 11 show a conventional projector type headlamp, in which FIG. 9 is a plan view, FIG. 10 is a side view, and FIG. 11 is a front view. FIGS. 12 and 13 are charts showing the optical characteristics of the above conventional example. ■... Concave mirror, 2... Light source bulb, 3... Convex lens, 4... Shade, 4a... Cut line, 5...
... Rotating parabolic reflector, 6... Front lens, 7...
- Vertical wall portion, 8... Reflector, 8a... Paraboloid of revolution reflective surface, 8b... Ellipsoid of revolution reflective surface, 9... Shade, 10... Front lens, 10a... convex lens.

Claims (1)

[Claims] 1. In a vehicle headlamp in which a light source bulb is provided near the focal point of the reflector and a lens is provided in front of the reflector, (i) the area including the center of the reflector is located near the light source bulb; (ii) The upper and lower regions of the paraboloid of revolution area are configured in the shape of an ellipsoid of revolution with a first focus near the light source bulb, and (iii) ) A shade is provided near the second focal point of the spheroidal reflecting surface, and (iv) the lens has a convex lens portion near the center thereof that focuses near the second focal point. Automobile headlights.