JPH01289002A - automotive headlights - Google Patents

Abstract

PURPOSE:To reduce the size of the width of a front lens and to prevent the expansion flood light from being shielded even though there is an obstacle at the side by making the center of a concave mirror in a rotary paraboloid form, and both ends of the lens to have the focus tendency stronger in the reflection light than in the parallel flux of light, presenting the stronger focus at the position closer to the both ends. CONSTITUTION:A concave mirror 7 is divided into the center part and the right and left end parts in the plane projection. The position around the center part is composed in a rotary paraboloid form so as to make the reflection light in a parallel flux of light even in the horizontal plane. The both ends are made in a parabola form in the horizontal section respectively and the horizontal section is composed in a specific form. And, in the horizontal section, when the angle between the light passage of the light emitted from the light source bulb and reflected at each point of the both ends, and the optical axis Z, is made theta, the point contacting to the rotary paraboloid of the center part, of either of the both ends, is made as the original value, and the direction approaching the optical axis Z of the angle theta in respect of the light projection direction is made as positive, the concave mirror is composed so that the closer the reflection point approaches the both ends of the concave mirror, the more the angle thetain the positive direction increases.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a headlamp for an automobile, and in particular, even if the front lens is a clear lens, a desired light distribution pattern can be obtained by the action of a reflector. This invention relates to a vehicle headlamp that has been improved so that it can be used.

[Conventional technology]

FIGS. 5 and 6 are horizontal sectional views showing conventional headlights, respectively.

The conventional headlight shown in FIG. 5 has a lamp housing 1
A paraboloid-shaped reflective surface 1a is provided on the inner surface of the rear wall, a light source bulb 2 is provided near the focal point of the reflecting surface 1a, and a prism-shaped front lens 3 is provided to cover the front opening. It is.

The light emitted from the light source bulb 2 as shown by arrow a is reflected on the reflective surface 1.
It is reflected at point a, becomes a light beam parallel to the optical axis Z, and is diffused by the prism of the front lens 3 as shown by the arrow QI+02 to form a desired light distribution pattern.

The cross section of the reflective surface 1a along a vertical plane parallel to the optical axis 2 has a parabolic shape, and within the vertical cross section, the light reflected by the reflective surface 1a is projected forward as a substantially horizontal parallel light beam.

The headlight of the conventional example (Fig. 5) described above is expensive because the front lens 3 must be composed of a prism lens.
And it tends to be heavy.

As a headlamp that is a simplified version of the conventional example, the structure shown in FIG. 6, which is called a reflector diffused type, is known.

The headlamp flap 4 of this conventional example has a light source bulb 2'
outgoing light.

(a) As a parallel light beam in the vertical plane, (b) In the horizontal plane, as a diffused luminous flux, reflect.

In order to have such a function, the above-mentioned glue flapper 4 is.

(b) The vertical cross section is a parabola, (b) The horizontal cross section forms a hyperbola.

It is configured as follows.

[Problem to be solved by the invention]

The conventional example of the glue flap diffuser face headlight (Fig. 6) is as follows:
The lens configuration is simple, and it is sufficient to use the transparent front lens 5, but (i) the effective utilization of the luminous flux is low unless the width Wl of the front lens 5 is increased, and (n) there are If there is an obstacle 6, there is a problem that the diffused light projection is blocked.

The present invention was created in view of the above-mentioned circumstances, and has the following features: (a) The lens structure is simple, lightweight, and inexpensive, and (b) The width of the front lens is smaller than the width of the reflector. (c) Even if there is an obstacle on the side, there is no risk of blocking the diffused light projection.

The object is to provide headlights for automobiles.

[Means to solve the problem]

In order to achieve the above object, the automobile headlamp of the present invention has the following features: (a) Similar to the conventional glue flap diffuser face headlamp,
The reflector is constructed so that its vertical cross section (vertical cross section parallel to the optical axis) forms a parabola.

(b) The reflector is divided into the vicinity of the center and the vicinity of both left and right ends in its planar projection.

However, the term ``classification'' here refers to the idea of categorizing things in terms of design considerations, and does not mean dividing or cutting the actual components.

(c) The area near the divided center is configured in the shape of a paraboloid of revolution, so that the reflected light is made into a parallel light beam even in the horizontal plane.

(d) Both ends of the division are configured so that one reflected light has a tendency to converge more than a parallel beam, and positions near both ends have a stronger tendency to converge.

[Effect]

According to the above configuration, i. The parallel light beam reflected by the paraboloid of rotation at the center forms a hot zone (high illuminance zone at the center) of the light distribution pattern.

i. The convergent reflected light once converges in front of the headlamp and is then projected further forward as a diffused light beam, forming a desired light distribution pattern.

(2) Since the above-mentioned diffused light is once condensed in front of the headlamp, it is not obstructed in front of the converging position even if there is an obstacle on the side.

K. As mentioned above, the light reflected by the reflector is.

It is mainly convergent light near the reflector, and also.

Since the reflected light at both ends is a parallel light beam, the effective utilization rate of the light beam is high even if the front lens is configured to be relatively small.

【Example〕

FIG. 1 is a three-sided view of a flefter 7 constructed by applying the present invention, (A) is a schematic plan view, and (B) is a front view.

(C) is also a side view.

It is.

Position the light source at point F.

As shown in the above figure (B), a vertically divided central part, left part, and right part are assumed.

The central zone, marked with spots, is configured in the form of a paraboloid of revolution.

The left and right end zones, which are not marked, are also configured so that their vertical cross sections (see FIG. 1(C)) form a parabola.

As a result, the reflected light becomes a horizontal parallel light beam in the vertical section (FIG. (C)).

As shown in this figure (B), point a from both ends toward the center.
Oy a O' + b Ot b O' ~d Oe
Take d O'.

The above point dot do' is on the boundary between the left and right zones and the center zone.

The space between d and -do' is located on a paraboloid of revolution.

Therefore, as shown in this figure (A), the reflected light (arrows d, d') at the point dotdo' becomes parallel to the optical axis Z-Z.

As shown in this diagram (B),
Set the axis and Y axis.

The area shown with parallel diagonal lines is the part where the X coordinate value is Xn.

Regarding the X coordinate, a curved surface is sequentially set from the point corresponding to doy do' toward the center (details will be described next).

As a result (see Figure 1 (A)), the angle θCO made by the reflected light C at point co with the optical axis Z is the angle θCO + point bo
b θbor point a (1θaoy is set to increase sequentially, thereby imparting diffusivity to the reflected light and forming a desired light distribution pattern.

The specific procedure will be explained next with reference to FIG.

Light source position! Let χ be the unit vector of light from F to point P on the reflector element (its coordinates are xi).

Let the unit vector of the reflected light be the neck.

Let the unit vector of the normal line on the reflector element be the awn.

Government = Su + 2 and Bi ......There is a relationship as shown in (1).

Further, suppose that the reflected light beam does not spread vertically but only horizontally by θXn.

becomes.

When the coordinates of point P are determined from the above equations (1) and (2), the plane equation of the reflector element is determined.

Therefore, the initial value (starting point) P point is determined at a certain location, and calculations are made from that point, or a point near the freta element is determined.

Further calculations are made from that point, or points near the flefter element are determined, etc. The calculations are repeated to form a curved surface, and the curvature of the completed curved surface changes continuously.

That is, the reflector elements are divided into smaller sections, and the value of X is precisely calculated.

The above calculation is extremely difficult to calculate by hand, but can be performed relatively easily by an electronic computer.

The curved surface calculated as described above reflects the light from the light source, and the reflected light does not spread up and down, but becomes a reflector that has the effect of spreading only left and right (Con=f(xn)).

(See Figure 1(A)).

θco<θbo<θaO Configure it so that

The relationship between the diffusion angle θX and XQ can be determined by calculating the luminous intensity distribution from the desired light distribution pattern as illustrated in FIGS. The angle θX is set using a power-of-X formula.

The desired light distribution pattern at this time may be determined according to the requirements of the automobile headlamp.

This configuration has been considered to be a drawback of the conventional reflector diffusion type headlamp (FIG. 6). This eliminates the problem of the lens having a large width and the fact that there is a standing wall on the side that blocks the diffused light.

FIG. 4 shows the reflector 7 according to the above embodiment (FIG. 1).
FIG. 3 is a three-sided view of a headlamp configured using

As in this example, it is sufficient that the front lens 8 is a transparent type (because the desired light distribution can be obtained by the reflector 7), and even if there is an obstacle (standing u, 9) on the side, the light distribution pattern can be changed. cannot be prevented from forming.

The present invention is suitable for application when the distance between the light source bulb 2' and the front lens 8 is large, as in this example (FIG. 4).

〔Effect of the invention〕

As explained above, according to the automobile headlamp according to the present invention, (a) the lens structure is simple, lightweight, and inexpensive, and (b) the width of the front lens is small. It is possible.

(e) Even if there is an obstacle on the side, there is no risk of blocking the diffused light projection, which is an excellent practical effect.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the structure and function of a reflector in an embodiment of an automobile headlamp according to the present invention. FIG. 2 is a chart showing the desired light distribution pattern in the above embodiment. FIG. 3 is an explanatory diagram of the design method of the reflector element in the above embodiment. FIG. 4 is a horizontal sectional view of the headlamp shown in FIG. 1 or using a flaper. FIGS. 5 and 6 are cross-sectional views showing conventional headlights, respectively. 1... Lamp housing, la... Reflective surface provided on the inner surface of the lamp housing, 2.2'...
Light source bulb, 3... Front lens constituted by a prism lens, 4... Conventional reflector diffused type power lamp glue reflector, 5... Clear front lens. 6...Obstacles present on the sides, 7...Reflectors in the embodiments of the present invention, P...Reflector elements. F...Light source position, Z...Optical axis, X...Horizontal coordinate axis, Y...' vertical coordinate axis.

Claims (1)

[Claims] 1. An automobile headlamp having a structure in which a light source bulb is installed near the focal point of the concave mirror, and a front lens is provided to cover the front opening of the concave mirror, comprising: (a) the concave mirror; , divided into a central portion and left and right end portions, (b) the central portion is configured in the shape of a paraboloid of revolution, and (c) the left and right end portions are each shaped like a parabola in vertical cross section. A headlamp for an automobile, characterized in that the headlamp has a horizontal cross section as follows. (i) The optical path of the light emitted from the light source bulb and reflected at each point on both ends of the concave mirror makes an angle θ with the optical axis; The point of contact is the initial value, (iii) the above angle θ is positive in the direction in which the light projection direction approaches the optical axis, and (iv) the above angle θ becomes positive as the reflection point approaches both ends of the concave mirror. increases to