JP2000173322A - Projection type headlight for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the weight of a convergent lens by forming a convergent lens into a Fresnel lens formed with a recessed and a projecting surfaces in both sides thereof, and manufacturing the convergent lens of plastic. SOLUTION: This headlight is provided with a light source 14, a reflector 10 and a convergent lens 18 arranged in rear of the reflector 10 in the light outgoing direction 16. The light emitted from the light source 14 is reflected by the reflector 10 as a light beam to be converged, and transmitted through the convergent lens 18. In this headlight, the convergent lens 18 is formed into a Fresnel lens, of which one surface is formed into a recessed surface and of which the other surface is formed into a projecting surface. The Fresnel lens is formed with a recessed surface 26 directed opposite to the light outgoing direction and a projecting surface 27 directed in the light outgoing direction, and an optical annular forming part 28 or a ring-like lens is arranged at least one surface of the convergent lens 18 so as to form the Fresnel lens. The convergent lens 18 is desirably made of plastic.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection type headlamp for a vehicle, comprising a light source, a reflector for reflecting light emitted from the light source as a converged light beam, and a reflector in a light emitting direction. And a convergent lens disposed behind the reflector for transmitting light reflected from the reflector, wherein the convergent lens has a surface curved convexly in the light emitting direction.

[0002]

2. Description of the Related Art A headlight of the above-mentioned type is known from DE-OS 44 07 108 A1. The headlight has a light source and a reflector,
The light emitted from the light source is reflected by the reflector as a converging light flux. A converging lens is arranged behind the reflector in the light emission direction, and light reflected from the reflector passes through the converging lens and is converged. The converging lens is formed as a plano-convex lens (plankonvexe Linse) having a plane facing the reflector opposite to the light exit direction and a surface curved convexly toward the light exit direction. The converging lens is usually made of glass and therefore has a high weight due to the construction of the lens in the form of a plano-convex lens, which leads to a high weight of the headlight. The converging lens is held on a separate support member,
The holding member is connected to the reflector, thus increasing the cost of manufacturing and assembling the headlight.

[0003]

An advantage of the headlight according to the invention with the arrangement according to claim 1 is that the lens has only a small weight, so that the weight of the headlight is correspondingly reduced. You.

[0004] Advantageous configurations of the headlight according to the invention are described below. With the configuration according to claim 2, the weight of the converging lens and thus of the headlight is further reduced. The manufacturing and assembly costs of the headlight are reduced by the configuration according to claim 3.

[0005]

DETAILED DESCRIPTION OF THE INVENTION FIG. 1 for a vehicle, especially a motor vehicle.
And the headlight shown in FIG. 2 is based on the projection principle (Projektionsprinzi).
p) and is used for forming a low beam (Abblendlicht) or fog beam (Nebellicht). The headlight has a concavely curved reflector 10 into which a light source 14 is inserted via an opening 12 in the top section of the reflector. The reflector 10 is made of metal or plastic, and the light source 14 can be an incandescent lamp or a gas discharge lamp. The reflector 10 is formed such that light emitted from the light source 14 is reflected as a light beam converged by the reflector. Reflector 1 in the direction of light emission
After 0, a converging lens 18 is arranged, and the light reflected from the reflector 10 passes through the converging lens, is refracted toward the optical axis 11, and is converged. Reflector 10
A blind 20 is arranged between the light source and the converging lens 18, the blind extending substantially below the optical axis 11 of the reflector 10 to block a part of the light reflected from the reflector 10, and thus a headlight. A light-dark boundary (Helldunkelgrenze) of the light beam emitted from the light source is formed. Blind 20
However, this can be omitted if the reflector 10 has been formed such that the light emitted from the light source 14 and reflected by the reflector 10 already has a light-dark boundary.

A reflector 10, a light source 14, and a converging lens 18, and possibly a blind 20, may also be arranged in the casing 22, the light exit aperture of the casing being a light transmissive plate (lichtdurchlaessige Scheibe) 24.
Covered by The plate 24 is almost smooth (glat
t), so that the light reflected from the reflector 10 and passed through the converging lens 18
Pass almost unaffected by the plate. Optionally, plate 24 has an optical profile (optische
The plate deflects and / or controls the light reflected from the reflector 10 and passing through the converging lens 18. A headlamp may be used to selectively form a low beam and a far beam, in which case the blind 20 enters the radiation path of light reflected from the reflector 10 to form a low beam. And light and dark boundaries (light and dark cutoff line)
And at least in part for the formation of the far beam, located outside the radiation path of the light reflected from the reflector 10, so that at least a majority of the light reflected from the reflector 10 is It is movable so that it can be emitted from a headlight.

In the embodiment, the converging lens 18 has a concave convex shape.
(konkavkonvexe Form), in which case the concavely curved surface 26 of the convergent lens faces the reflector 10 in the direction opposite to the light exit direction 16 and the convexly curved surface of the convergent lens 27 is oriented in the light emitting direction 16. Instead of a concavely curved surface, the converging lens 18 may have at least a substantially flat surface (ebene Seite) 26 facing away from the light exit direction 16. The converging lens 18 is embodied as a Fresnel lens and has a ring-shaped optical profile 28 on at least one surface, in this embodiment a convexly curved surface 27 facing the light exit direction 16. . The optical profiles (moldings or annular lenses) 28 are formed to extend at least approximately concentrically with one another. Reflector 10
The light reflected by and traveling beyond the blind 20
Optical profile 2 upon passage through converging lens 18
The light 8 is refracted toward the optical axis 11. Due to the ring-shaped optical profile 28, the converging lens 18 has a low thickness and thus a low weight.

The converging lens 18 is made of a plastic, preferably a thermoplastic which is sufficiently thermoformable and UV-stable. As the thermoplastic plastic, for example, polycarbonate (PC) or polymethyl methacrylate (PMMA) may be used. However, optionally, the converging lens 18 may be made of glass, but such a converging lens has a greater weight than one made from plastic.

The converging lens 18 is formed in a substantially circular shape in the embodiment as viewed in the cross section of FIG. 2, and has a cylindrical shape facing the reflector 10 in the direction opposite to the light emitting direction 16 at the edge of the converging lens. The additional portion 30 may be integrally formed. The additional portion 30 extends from the edge of the converging lens 18 to a front edge 32 of the reflector 10 facing the light emitting direction 16. The front edge portion 32 of the reflector 10 may be formed in an outward flange shape, and the additional portion may be in the light emitting direction 1.
6 has an outwardly projecting flange 34 at the edge facing in the opposite direction. The converging lens 18 is a flange 34 of the addition part 30 and is provided with one or more fixing members in the form of, for example, rivets 36 or screws.
May be coupled to the flange of the leading edge 32 of the lens, thereby holding the converging lens 18 on the reflector 10. In this manner, the addition section 30 forms a support member, and the converging lens 18 is held by the reflector 10 via the support member. The additional portion 30 may be formed closed over the entire circumference, or may have an opening to allow ventilation.

[Brief description of the drawings]

FIG. 1 shows a vertical longitudinal section through a headlight according to the invention.

FIG. 2 is a cross-sectional view taken along line II-II of FIG.

[Explanation of symbols]

Reference Signs List 10 reflector, 11 optical axis, 12 aperture, 14 light source, 16 light emitting direction, 18 converging lens, 20 blind, 22 casing, 24 plate, 26, 27 surface, 3
2 Front edge, 34 flange

Continued on the front page (72) Inventor Horst Oschmann, Germany Strut-Hermaashof an den Birken 6 (72) Inventor Gerd Langhammer Germany Vooter-Farnloh da Rosenpfert 5 (72) Inventor Siegmar Glaser Germany Federal Republic of Trusetal Grabborn 1

Claims (6)

[Claims] 1. A projection headlight for a vehicle, comprising:
A light source (14), a reflector (10) for reflecting light emitted from the light source (14) as a converged light beam, and a reflector (10) disposed behind the reflector (10) in the light emitting direction (16). ) Is provided with a converging lens (18) for transmitting light reflected from the converging lens, wherein the converging lens has a surface (27) convexly curved in the light emitting direction (16). A projection headlight for a vehicle, characterized in that the lens (18) is formed as a Fresnel lens. 2. The converging lens (18) is provided with a light exit direction (1).
2. The headlight according to claim 1, which has at least a substantially flat surface facing in the opposite direction to (6). 3. The converging lens (18) is provided with a light exit direction (1).
2. The headlight according to claim 1, which has a concavely curved surface (26) facing in the opposite direction to (6). 4. The converging lens (18) is made of plastic,
2. The method according to claim 1, wherein the material is made of a thermoplastic material.
The headlight according to any one of claims 1 to 3. 5. The convergent lens (18) is integrally formed with at least one support member (30), and the convergent lens (18) is connected to the reflector (10) via the support member.
The headlight according to any one of claims 1 to 4, wherein the headlight is held by a headlight. 6. The converging lens (1), wherein the support member (30) is provided.
6. The headlight according to claim 5, wherein the headlight is formed as at least a substantially cylindrical additional portion.