JP2773044B2 - Projector lamp - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

The present invention relates to a projector lamp used for an automobile headlamp or fog lamp.

[Prior art]

FIG. 3 is a cross-sectional view showing an example of a conventional projector lamp 31. A light source 32 is disposed substantially coincident with one focal point of an ellipsoidal reflecting mirror 33, and a projection lens is provided on the other focal point side.
34, and a light-shielding plate 35 is provided at a position substantially at the focal point of the projection lens 34.
The light beam focused on the other focus by the projection lens 34
When the light is projected forward, light beams in an unnecessary part as a headlamp, for example, are shielded by the light-shielding plate 35 so as to have a prescribed light distribution characteristic. At this time, since it is generally desired that the light distribution for an automobile is wide in the horizontal direction and narrow in the vertical direction, the ellipsoidal reflecting mirror 33 may have an elliptical shape whose cross section perpendicular to the optical axis Z has a horizontal axis as a long axis. A triaxial ellipsoid 33A (see FIG. 4) having a shape or a composite ellipsoid 33B (see FIG. 5) in which an arbitrary ellipse is combined at an arbitrary position is used. Further, when the projector lamp 31 is used as an automobile headlamp, since it is necessary to prepare a left-hand traffic and a right-hand traffic depending on a destination or the like, the elliptical reflecting mirror 33 is basically left-right symmetric. Light distribution characteristics of left and right objects are obtained, and a dedicated light shielding plate 35 is used for each of the left and right traffic. Accordingly, also in the triaxial ellipsoid 33A or the composite ellipsoid 33B, one of the focal points and the other focal point are provided on the optical axis Z in order to secure the left-right symmetry.

[Problems to be solved by the invention]

However, when this projector lamp 31 is to be used as, for example, a headlamp for a low beam, it is required that almost no upward light beam is present except for some positions due to related standards and the like. As shown in FIG. 6, approximately half the area of the original light distribution pattern H is covered by the shadow S of the light shielding plate 35, and only about 50% of the light amount from the light source 32 can be used.
There has been a problem that the headlamp has a low light flux utilization rate and is darker than the power consumption, and solving this point has been an issue.

[Means for Solving the Problems]

The present invention provides a projector lamp including a light source, an elliptical reflector, a light shielding plate, and a projection lens as a specific means for solving the above-described conventional problem. Providing a projector lamp characterized by a composite elliptical reflective surface with asymmetrical left and right sides that reduces contact makes it possible to improve the luminous flux utilization rate and provide a brighter projector lamp with the same power consumption. This is to solve the above-mentioned conventional problems.

【Example】

Next, the present invention will be described in detail based on an embodiment shown in the drawings. FIG. 1 shows the principle of the embodiment of the present invention. In FIG. 1, a reference numeral 1 denotes a projector lamp. This projector lamp 1 has a light source 2 substantially at one focal point F1 of an ellipsoidal reflecting mirror 3. It is the same as the conventional example that the light shielding plate 4 is disposed further forward and the projection lens 5 is further disposed forward. According to the present invention, the shape of the ellipsoidal reflecting mirror 3 is determined according to the shape of the light shielding plate 4. In the following, in order to facilitate understanding, the elliptical reflecting mirror 3 is defined based on an optical axis Z of the projector lamp 1 and a vertical plane PL orthogonal to the optical axis Z and provided with the light shielding plate 4. In other words, the light from the light source 2 reaches the vertical plane PL while being reflected and converged by the ellipsoidal reflecting mirror 3, but is provided in conformity with the vertical plane PL. A part of the light shielding plate 4 is shielded, so that the light distribution characteristic is determined and the light amount is lost at the same time. Here, considering the relationship between the portion of the elliptical reflecting mirror 3 and the light shielding plate 4 in more detail, the light shielding plate 4 is arranged along the horizontal line X of the vertical plane PL. The light from the lower half 3a below the optical axis Z of the elliptical reflecting mirror 3, which generates a substantially conical light flux, is almost completely blocked by the light shielding plate 4. Actually, the light shielding plate 4 is provided with a cutout portion 4a for generating a slightly upward light to the upper left in order to illuminate a left roadside zone and a road sign, for example, for left-hand traffic. I have. Therefore, the lower half 3a of the elliptical reflecting mirror 3 is formed as a compound elliptical reflecting surface according to the shape of the light shielding plate 4, for example, so as to generate another focal point F2 toward the notch 4a. Alternatively, the relative eccentricity of the lower half is increased, that is, the light beam emitted from the lower half 3a is reduced by reducing the diameter of the ellipsoidal reflecting mirror and narrowing the light beam emitted. It is possible to reduce the ratio of being shielded by the light shielding plate 4. Further, the movement of the other one focal point F2 of the lower half portion 3a is not limited to the above-described cutout portion 4a direction, that is, is not limited to the horizontal line X direction. When the projector lamp 1 is used as a headlamp, there is a possibility that upward light is likely to be generated. Therefore, in practice, it is necessary to perform sufficient optical path calculations or experiments to keep it within the range permitted by the standard. It is important. FIG. 2 shows the light distribution pattern HP formed by the elliptical reflecting mirror 3 formed according to the above description. As is clear from the drawing, the shadow HS regulated by the light shielding plate 4 is shown in FIG.
It is clear that the area of the portion is reduced, and the luminous flux utilization factor is improved. In the present invention, since the shape of the elliptical reflecting mirror 3 is also affected by the shape of the light shielding plate 4, for example, the elliptical reflecting mirror 3 cannot be shared for left-hand traffic and right-hand traffic. However, this can be done by turning left and right on the drawing,
This does not lead to an increase in the number of steps such as design man-hours.

【The invention's effect】

As described above, according to the present invention, when the elliptical reflecting mirror is a composite elliptical reflecting surface that is asymmetrical on the left and right sides to reduce the contact of light to the light shielding plate, the light from the elliptical reflecting mirror is blocked by the light. The present invention has an excellent effect of improving the luminous flux utilization rate of the projector lamp by minimizing the amount of the light which is abutted and shielded by the plate and lost, thereby realizing a bright projector lamp.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of a projector lamp according to the present invention, FIG. 2 is an explanatory view showing an example of light distribution characteristics according to the same embodiment, FIG. FIG. 5 is a cross-sectional view of one example of the conventional example, FIG. 5 is a cross-sectional view of another example of the conventional example, and FIG. 6 is an explanatory diagram showing light distribution characteristics of the conventional example. DESCRIPTION OF SYMBOLS 1 ... Projector lamp 2 ... Light source 3 ... Ellipsoidal reflecting mirror 4 ... Shielding plate 4a ... Notch 5 ... Projection lens X ... Horizontal line Z ... Optical axis PL ... Vertical plane HP ... Light distribution Pattern HS …… Shadow

Claims (1)

(57) [Claims] 1. A projector lamp comprising a light source, an ellipsoidal reflecting mirror, a light shielding plate, and a projection lens, wherein the elliptical reflecting mirror is a compound elliptical reflecting surface which is asymmetrical on the left and right sides to reduce contact of light on the light shielding plate. A projector lamp characterized by having a surface.