JPH0140086Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a rectangular headlamp used as an automobile headlamp.

[Prior Art] As shown in FIG. 11, a headlamp has a cylindrical light source (filament) 3 placed approximately on the focal point of a reflecting mirror 2 having a front lens 1 disposed in its front opening, with its axis aligned with the lamp axis. (C-6 type), in which the cylindrical filament 3 is arranged so that its axis is parallel to and horizontal to the lamp axis, as shown in Figure 12. format (C-8 format)
There is. Both types have two filaments (C-6/C-6 type, C-8/C-8 type).
format).

A model with one filament generates only a running beam, and a model with two filaments generates a running beam and a passing beam, but in both cases, the running filament is placed approximately at the focal point of a reflecting mirror (paraboloid of revolution reflector). , the passing filament is placed above the running filament. A lens cut is carved into the front lens 1 in order to obtain a desired light distribution.

By the way, cylindrical light sources generally exhibit a luminous intensity distribution that is strongest in the direction perpendicular to the central axis of the light source 3 and weakest in the axial direction, as shown in Fig. 13, and is used in rectangular headlights with a narrow vertical width. In this case, Fig. 14 (C
15 (C-6 format) or FIG. 15 (C-8 format), the following drawbacks occur.

() It is difficult to obtain the desired light distribution because the light utilization rate is poor and the luminous flux output of the reflecting mirror is not sufficient.

() Since the luminous intensity is strong in the direction of the upper and lower ineffective reflective surfaces of the reflector, the scattered light reflected from these surfaces is emitted upward from the horizontal direction of the lamp, dazzling oncoming vehicles.
Severe degree of dazzling in the fog.

[Object of the invention] An object of the invention is to provide a rectangular headlamp that has a high light utilization rate and generates less unwanted light.

[Summary of the invention] This invention forms a reflecting mirror so that the front opening of the main reflecting surface has a horizontally long rectangular shape, and a front lens is disposed in the front opening of this reflecting mirror. In a rectangular headlamp in which a light source is arranged approximately parallel to the mirror axis, the light source is a flat columnar light emitting body whose cross section has a ratio of the short axis to the long axis of 2/3 or less, and the long axis is in the vertical direction. It is characterized by being arranged so that.

[Example] Figures 1 to 3 show an example of the present invention, in which the main reflecting surface (effective reflecting surface) is a paraboloid of revolution, and the front opening is a horizontally elongated square ( A reflecting mirror is formed so that the ratio of the vertical dimension to the horizontal dimension is 3/4 or less. 12 is a front lens disposed in the front opening of this reflecting mirror 11, and a lens cut is formed in the area to obtain the desired light emission. It is divided into A, B, and C. Reference numeral 13 denotes a light source, which is an elliptical cylindrical light emitting body as shown in FIG.
And they are arranged so that their long axes are in the vertical direction.
It is desirable that the light emitting body 13 has a small ratio K of the short axis 2b to the long axis 2a of its cross section.

The luminous intensity distribution within the reflecting mirror 11 of the rectangular headlamp having the above structure is as shown in FIG. In other words, it has a luminous intensity distribution that is weak in the vertical direction (vertical direction) and strong in the horizontal direction (horizontal direction), with a large amount of luminous flux directed toward the effective reflecting surface of the reflector 11, and a large amount of luminous flux directed toward the upper and lower ineffective reflecting surfaces. Since the amount of light is reduced, the utilization rate of light is increased, and undesired light that dazzles oncoming vehicles is also reduced.

Next, the luminous intensity distribution of a flat columnar light emitter, an example of which is an elliptical columnar light emitter, will be explained with reference to FIG.

The luminous intensity I(θ, φ) at the reflection mirror incident point P(θ, φ) of the elliptical columnar light emitter 13 having the major axis 2a, the minor axis 2b, and the coil length l is given by the following equation.

I (θ, φ) = I ₀ Sinφ (sin ² θ + K ² cos ² θ) ^1/2 …(1) Here, I ₀ is the maximum luminous intensity of the light source, and K is the minor axis major axis ratio, which is 2b/2a. .

On the other hand, in the case of the conventional C-6 format, I (θ, φ) = I ₁ sin φ (1-sin ² φ cos ² θ) ...(2) In the case of the C-8 format, I (θ, φ )=I ₂ sinφ …(3).

In the above equations (2) and (3), I ₁ and I ₂ are the maximum luminous intensities of the light sources, respectively, and since the C-6 format and C-8 format have the same light source shape, I ₁ =I ₂ .

As mentioned above, the luminous intensity distribution when each light source type is applied to a rectangular reflecting mirror with narrow vertical width is shown in Figure 3 (this example), Figure 14 (C-6 type), and Figure 15 (C-6 type).
8 format), and in the case of the present invention, there is less dazzling light and the light utilization rate is high.

Next, in order to clarify the proportion of the effective luminous flux and the proportion of the ineffective luminous flux (the luminous flux that enters the upper and lower ineffective reflective surfaces) of the above three types, the incident luminous flux with respect to each reflective surface area is calculated. Luminous flux emitted in the area of solid angle dω
Since dF is dF=Idω=Isinφddθ, in the case of an elliptical cylindrical light emitter (this example), F=I ₀ ∫〓∫〓sin ² φ (sin ² θ+K ² cos ² θ) ^1/2 dφdθ C For -6 format, F=I ₁ ∫〓∫〓sin ² φ (1-sin ² φcos ² θ) ^1/2 dφdθ For C-8 format, F=I ₂ ∫〓∫〓sin ² φdφdθ becomes.

Perform each of the above integrations in the integral areas θ and φ for the effective reflecting surface of the reflector, the upper and lower ineffective reflecting surfaces, and the change in dimensions of the lamp (change in the vertical dimension Y for a fixed horizontal dimension, for example, 200 mm), and calculate the elliptical cylindrical light emission. body C-6
The format and luminous flux ratio for C-8 format are shown below.
The result will be as shown in Fig. 4 a, b and Fig. 5 a, b. (still,
In this case, it is assumed that the ineffective reflective surface of the part of the reflector where the light bulb, etc. is attached is 40 mmφ, and the light source is placed at the focal point (f=30 mm) of the paraboloid of revolution. ) From FIGS. 4a and 4b, it can be seen that the luminous flux utilization rate of the rectangular headlamp using the elliptical cylindrical light emitter is superior to both the C-6 type and the C-8 type. In particular, it can be seen that the luminous flux utilization increases as the aspect ratio of the lamp body size becomes smaller than 150/200 (narrower vertically) and as the short-to-long axis ratio K of the ellipse becomes smaller.

Furthermore, from Figure 5 a and b, the ineffective luminous flux rate of a rectangular headlamp whose light source is an elliptical cylindrical light emitter is 1:1 to 1 for the C-6 type. :
1.4 range, 1:1 to C-8 format
It can be seen that small values are shown in the range of 3:20.

Furthermore, as the ellipse minor axis/major axis ratio K becomes smaller, the light utilization efficiency increases, but this result becomes noticeable in the range of 2:3 or less.

Incidentally, the light distribution characteristics of the above embodiment are as shown in FIG. Further, in the above embodiment, an elliptical columnar light emitter was used as the flat columnar light emitter, but a flat prismatic light emitter 13' as shown in FIG. 7 or a columnar light emitter with a diamond-shaped cross section as shown in FIG. 13". Furthermore, as shown in FIG. 9, two light sources 13-
1, 13-2, one of which is a running filament,
The other filament can be used as a passing filament and can be applied to square headlights for automobiles. In this case, the light distribution characteristic due to the traveling beam is as shown in FIG. 10a, and the light distribution characteristic due to the passing beam is as shown in FIG. 10b.

Specific embodiments of a rectangular headlamp having a flat columnar light emitting body include a configuration in which the flat columnar filament is directly attached to a reflector, as well as a light bulb such as an incandescent light bulb, a halogen light bulb, etc., equipped with a flat columnar filament. One possible option is to attach it to a reflector.

Further, in this embodiment, a paraboloid of revolution is used as the main reflecting surface of the reflecting mirror, but other reflecting surfaces such as an ellipsoid of revolution, a hyperbolic surface of revolution, and a multiple reflecting surface may be used.

[Effect] As described above, according to the present invention, a rectangular reflecting mirror with a narrow vertical width, especially one in which the ratio of the vertical dimension to the horizontal dimension is smaller than 3:4, has a flat columnar light emitting body, especially the short axis to the long axis. Since the flat columnar light emitters with a ratio of 2/3 or less are arranged so that their central axes are approximately parallel to the reflector axis and their long axes are vertical, the luminous flux incident on the effective reflecting surface of the rectangular reflector is increases, and the luminous flux incident on the upper and lower ineffective reflective surfaces decreases. For example, a reflector with an aspect ratio of 1:2 increases the luminous flux utilization by 5 to 15% compared to a conventional C-8 type headlamp, and by 40 to 50% compared to a C-6 type headlamp. 10 to 30 compared to the C-8 format.
%, the ineffective light flux (dazzling light) directed toward the upper and lower surfaces of the reflecting mirror can be reduced by 5 to 25% compared to the C-6 type.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an embodiment of a rectangular headlamp according to the present invention, and FIG. 2 is a perspective view illustrating an example of the shape of a flat columnar light emitter and the luminous intensity distribution of its light emission in the same embodiment. , Fig. 3 is a perspective view showing the luminous intensity distribution when the same light emitting body is placed inside a reflecting mirror, Fig. 4 a,
b is a diagram showing the comparison results of effective luminous flux utilization rate with the conventional example, Figures 5a and b are diagrams showing the comparison result of the ineffective luminous flux rate with the conventional example, Figure 6 is the light distribution pattern, and Figure 7 and Fig. 8 are perspective views showing other shapes of flat columnar light emitters, respectively, and Fig. 9 is a perspective view when applied to an automobile headlamp having two light emitters, a running filament and a passing filament. , FIGS. 10a and 10b are the same light distribution patterns, FIGS. 11 and 12 are perspective views showing conventional examples, FIG. 13 is a diagram showing the luminous intensity distribution of a cylindrical light source, and FIGS. 14 and 15.
Each figure is a perspective view for explaining the luminous intensity distribution when a cylindrical light source is placed inside a rectangular reflecting mirror. 11...Reflector, 12...Front lens, 13,
13', 13'', 13-1 and 13-2...flat columnar light emitters.

Claims (1)

[Scope of utility model registration request] A reflecting mirror is formed so that the front opening of the main reflecting surface has a horizontally long rectangular shape, a front lens is arranged in the front opening of this reflecting mirror, and a light source is arranged inside the reflecting mirror approximately parallel to the reflecting mirror axis. In the rectangular headlamp, the ratio of the short axis to the long axis of the cross section of the light source is 2/3.
A rectangular headlamp characterized by having the following flat columnar light emitting body arranged so that its long axis is in the vertical direction.