JPS61179001A - Composite reflecting mirror for head lamp - 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 parabolic reflector for a headlamp used by being attached to a vehicle such as an automobile, and relates to a compound reflector having a plurality of reflecting surfaces. .

(Prior art) Automobile headlamps reflect the radiant and diverging light beam emitted from the light source by a parabolic reflector to produce a forward light beam, and adjust the direction of this light beam using a cut group on the front lens. , the required light distribution can be obtained.

The prism principle is used to correct the direction of the light beam using the cut group of the front lens, and in particular, in order to form left and right expansion, a cylindrical cut (which can be regarded as a continuous prism) is used.
A piece whose canted portion is canted to form a cylindrical concave curved surface is used in practice. The cut portion of lens piece a is shown in FIG. A cylindrical cut b is made on the inner surface of the lens piece, and when the parallel reflected light beam C reflected by the parabolic reflector is irradiated to the outside through the cylindrical cut b, it is spread to the left and right. Recently, the air resistance of cars has become an issue, and the angle of inclination θ of the front lens that receives wind pressure is
Larger headlamps are now required.

Therefore, the lens piece a is set at a certain range of angle (θ≦200
), a characteristic of the cylindrical cut b is that the luminous flux projected onto the screen d falls below the horizontal line e on the edge side (hereinafter referred to as the light sagging phenomenon), which makes it difficult to properly arrange the cut. The angle of inclination cannot be large because it does not become light. Therefore, there is a limit to how much the light flux can be spread by the cylindrical cut of the front lens, and a reflector has been sought to spread the light flux.

For example, as a reflecting mirror that spreads the light beam in the horizontal direction,
The one disclosed in Japanese Patent No.-145002 is known.

In this known reflecting mirror, when a light source is placed near the focal line of the parabolic reflecting mirror, the reflected light spreads in the horizontal direction and substantially in the vertical direction, as shown in Figure 7. A reflected luminous flux with no .

The light distribution pattern in this case is the case where there is no lens in front of the reflecting mirror. As is clear from this light distribution pattern, the left and right spread angles are within 2O2, and no light sagging phenomenon is observed.

However, in the case of automobile headlamps, differential light distribution is particularly important, and the spread angle to the left and right is ±15° according to the standard, but in practice it is desirable that the light be distributed to ±30°. It is rare. Therefore, when using the known reflecting mirror, there is a problem in that in order to obtain a practical misaligned light distribution, the light flux must be modified by lens cutting by the front lens to form an appropriate misaligned light distribution. In particular, forming a substantially symmetrical light distribution centering on the front as described above means that the curve where each focal length F of the parabolic column and the tangent line at each vertex of the parabolic column are connected to the same parabola as the focal length F described above. This seems to be caused by the following.

(Problems to be Solved by the Invention) The present invention solves the problems of the conventional example in which the front lens corrects the light distribution and the light flux, and the problem of the light sagging phenomenon that occurs when the front lens is installed at an angle. This is what we are trying to solve.

(Means for Solving the Problems) The present invention is a specific means for solving the problems in the conventional example described above. To provide a composite reflector for a headlamp, in which a plurality of reflecting mirrors each having a parabolic cylindrical reflecting section are set such that the focal length of each of the parabolic cylindrical reflecting sections is set to be gradually larger as the distance from the light source increases. As the focal length gradually increases, the horizontal light distribution expands to a required predetermined angular range, eliminating the need for light flux adjustment using a front lens. Further, in addition to the above-mentioned configuration, a part or all of each parabolic cylindrical reflection section is configured so that reflected light in a position range a predetermined distance X away from the side of each parabolic cylindrical reflection section near the light source is directed toward the front. By specifying that the ratio of X and OL is set to 0.4≦-≦0.6 OL, the effective light emission length of the light source is Even if the light fluctuates, the front illumination will have the planned light distribution characteristics and no luminescent floor will occur.

(Embodiment) Next, the present invention will be explained in more detail based on the illustrated embodiment. ``■'' is a rectangular composite reflector having an overall parabolic surface, and the composite reflector ``l'' is a headlamp reflector. The front lens 2 is attached to the front side.

The composite reflecting mirror 1 has a reflecting surface that is vertically divided into a plurality of parabolic cylindrical reflection sections when viewed from the front, and the divisions are symmetrical about the mounting position 3 of the bulb or light source. It is formed. In the case of the illustrated embodiment, the above-mentioned division is divided into eight parts, which are numbered as parabolic cylindrical reflection parts 1-1 to 1-8 from the center side to the side faces. The focal length of each of these parabolic cylindrical reflecting portions is set to gradually increase from the center side toward the side surface side, and each focal line intersects at one point. In this way, by sequentially increasing the focal length of each parabolic cylindrical reflection section, the reflected light will spread in the horizontal direction, and the entire reflecting mirror will have a light distribution of -9 turns as shown in Figure 4, for example. become.

As is clear from this figure, the spread to both sides reaches approximately ±30°, which is ideal.

The above light distribution and turn are those in which the reflected light from each parabolic cylindrical reflection section 1-1 to 1-8 is directly projected onto the screen without passing through the front lens. This is the turn when a point light source (lφ spherical light source) is placed. In this case, one end (inner side) of the reflected light from each parabolic cylindrical reflection section comes to be caught in the center of the screen. In other words, as shown in FIG.
-5a also has its ends caught in the center, and these parabolic cylindrical reflection parts are provided symmetrically, resulting in a light distribution pattern that spreads approximately symmetrically on both sides. In addition, as is clear from these light distribution patterns, the reflected light reflected by the parabolic cylindrical reflection parts 1-1 to 1-3 near the center, which have short focal lengths, forms a wide light band that widely spreads left and right. form,
The reflected light from the parabolic cylindrical reflection parts 1-5 to 1-8 located on the side faces forms a spot-like light band near the center of the screen, and these reflected lights alone can be used as a headlamp. This results in an ideal light distribution and turn, and almost no need for adjusting the luminous flux with the lens.

The light source actually used, ie, the bulb 4, is of the c-B filament type and includes main and sub filaments 5 and 6, as shown in FIG.

And the filament is located vertically with respect to the reflector,
It has a substantially constant effective emission length OL. The effective light emitting length of this light source also spreads the luminous flux in the lateral direction.

Seen from the front, each of the parabolic cylindrical reflection sections 1-1-1-8 has
Except for the parabolic cylindrical reflection part 1-8 at the end, the width is gradually narrowed as it moves away from the center, that is, the light source, and the part of each parabolic cylindrical reflection part shown by the dotted line 7 closer to the light source becomes the focal point. The light from the located light source is set to go to the center of the light distribution pattern, that is, directly in front, and the area shown by diagonal lines 8 in the vicinity forms a spot. In this case, the range in which the reflected light directed directly in front is reflected is closely related to the effective light emission length OL of the front light source, so the range must be specified. In other words, the position range that is a predetermined distance X away from the side closer to the light source of each parabolic cylindrical reflection part needs to face in the front direction, and the effective light emitting length of the light source also depends on the type of bulb used. , for example, in addition to the C-8 filament type, discharge lamps can also be used, so it must be determined by the effective emission length OL of the light source itself. Therefore, the range in which the reflected light is directed toward the front is 0.4≦−≦
It is set to be 0.6 OL. The focal length and width of each parabolic cylindrical reflection section are determined by the size of the composite reflection mirror in actual use (approximately 18011+11), and the values are shown in Table 1.

Table 1 (Effects of the Invention) As explained above, the composite reflector according to the present invention improves reflection by setting the focal lengths of the parabolic cylindrical reflectors arranged in parallel in the vertical direction to be gradually larger as the distance from the light source increases. The light can be spread to about ±30' in the left and right direction, and this spread is the ideal spread angle of the irradiated light for headlights, and there is almost no need for light flux correction with a lens, at most about ±5°. This has the excellent effect of eliminating the troublesome lens cutting process.

In addition, by gradually increasing the focal length, the entire reflecting mirror can be made into a horizontally elongated elliptical paraboloid with high utilization of light and good reflection efficiency. If the mirror and the amount of light used are the same,
It can be a reflective mirror with a shallow depth.

In addition, the width of the parabolic cylindrical reflection section narrows as it moves away from the light source, and each parabolic cylindrical reflection section is provided with a reflection section facing directly in front of it and a spot reflection section, making it ideal for use as a headlamp. As long as the light distribution and mother turn are obtained and there is no need to correct the spread of the front lens, no light sagging phenomenon will occur even if the front lens is tilted at a steep angle of 40 to 60'. This also has the excellent effect of making it possible to obtain a head rung that is resistant to wind pressure.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway front view of a headlamp using the composite reflector for a headlamp according to the present invention, and FIG.
The figure is a partially cutaway top view of the headlamp, Figure 3 is a sectional view taken along the line ■-■ in Figure 1, Figure 4 is an A-turn diagram of the light distribution of the compound reflector, The figure shows the light distribution/? turn diagram,
FIG. 6 is a schematic perspective view showing the state of refraction of light in some cylindrical cut pieces formed in the lens, and FIG. It is a light distribution/setan diagram of the reflecting mirror according to the invention of Publication No. 58-145002. 1... Composite reflecting mirror 1-1 to 1-8... Parabolic cylindrical reflecting section 2...
...Lens 3...Light source mounting position 4
...Bulb 5,6...Filament OL...Effective light emitting length Figure 1 Figure 4 Figure 5■ Figure 6 Figure 7■

Claims (5)

[Claims] (1) In a composite reflector having a parabolic cylindrical reflection section that is vertically divided into a plurality of sections on the left and right around the mounting position of the light source, each focal length of the parabolic cylindrical reflection section is set as follows. A composite reflector for a headlamp, characterized in that the mirror is set to become larger as the distance from the light source increases. (2) The composite reflector for a headlamp as described in item (1) above, wherein the front view width of the parabolic cylindrical reflector is gradually narrowed as the distance from the light source increases. (3) In a composite reflector having a parabolic cylindrical reflection section that is vertically divided into a plurality of sections on the left and right with the mounting position of the light source as the center, the focal length of the parabolic cylindrical reflection section is defined as the focal length of the light source. The distance from the side of each parabolic cylindrical reflection part that is closer to the light source is set to be larger in order, and the reflected light in a position range that is a predetermined distance A composite for a headlamp, characterized in that the ratio of X and CL is set to be 0.4≦X/CL≦0.6, where CL is the effective light emission length of the light source. Reflector. (4) When a front lens is attached to the composite reflector, the front lens is configured to set only the vertical light distribution, and the composite reflector is set to perform the horizontal light distribution. A composite reflector for a headlamp according to items (1) and (3). (5) Items (1) and (3) above, characterized in that when a front lens is attached to the composite reflector, the optical path correction in the horizontal direction by the front lens is substantially 5 degrees or less.
Composite reflector for headlamps as described in ).