Automotive projector type headlight

• US 4,851,968 A
• Filed: 09/29/1988
• Issued: 07/25/1989
• Est. Priority Date: 09/29/1987
• Status: Expired due to Term

• Current Assignee: Koito Seisakusho Company Limited
• Original Assignee: Koito Seisakusho Company Limited
• Inventors: Nino, Naohi
• Primary Examiner(s): Lazarus, Ira S.
• Assistant Examiner(s): Cole, Richard R.
• Application Number:
  US07/250,881
• Time in Patent Office: 299 Days
• Field of Search: 362/61, 362/80, 362/83, 362/308, 362/299, 362/327, 362/328, 362/329, 362/346, 362/298
• US Class Current: 362/539
• CPC Class Codes: F21S 41/14 characterised by the type of light source
• CPC Class Codes: F21S 41/265 Composite lenses; Lenses with a patch-like shape
• CPC Class Codes: F21S 41/321 the reflector being a surface of revolution or a planar surface, e.g. truncated
• CPC Class Codes: F21S 41/43 characterised by the shape thereof

Abstract

A projector type headlight is disclosed, which comprises a concave reflector having first and second focuses on an optical axis thereof; a light source located on or at least near the first focus of the concave reflector; a shade plate positioned in front of the concave reflector, the shade plate having an upper edge located in the vicinity of the second focus of the concave reflector; and a converging lens located in front of the shade plate in such a manner that a focus of the lens is positioned on the upper edge of the shade plate, wherein the optical axis of the concave reflector is inclined with respect to an optical axis of the converging lens.

Claims

1. A projector type headlight comprising:

a first concave reflector having first and second focuses on an optical axis thereon;

a first light source located on or at least near said first focus of said concave reflector;

a shade plate positioned in front of said concave reflector, said shade plate having an upper edge located in the vicinity of said second focus of the concave reflector; and

a first converging lens located in front of said shade plate in such a manner that a focus of the lens is positioned on said upper edge of said shade plate,

wherein the optical axis of said concave reflector is inclined with respect to an optical axis of said converging lens.

2. A projector type headlight as claimed in claim 1, in which said concave reflector has an ellipsoidal light reflecting surface formed on an inside face thereof.

3. A projector type headlight as claimed in claim 2, in which said concave reflector has one half of said ellipsoidal light reflecting surface thereof cut out.

4. A projector type headlight as claimed in claim 3, further comprising a cap which partially covers said light source to block the light rays from said light source from travelling toward the cut out part of the concave reflector.

5. A projector type headlight as claimed in claim 4, in which said light source is a filament of an electric bulb.

6. A projector type headlight as claimed in claim 3, further comprising an upper beam projecting unit by which an independent light beam is produced.

7. A projector type headlight as claimed in claim 6, in which said upper beam projecting unit comprises:

a second concave reflector having a parabolic light reflecting surface, said second light reflector being arranged below said first concave light reflector and integral therewith;

a second light source arranged behind said first light source and located on or at least near a focus of said second concave reflector; and

a corrugated lens arranged in front of said second concave reflector to pass therethrough light rays which have been emitted from said second light source and reflected by said second concave reflector.

8. A projector type headlight as claimed in claim 7, in which an optical axis of said second concave reflector is in parallel with the optical axis of said first converging lens.

9. A projector type headlight as claimed in claim 7, in which said parabolic light reflecting surface of said second concave light reflector is a combination of various reflecting surfaces which include surfaces provided by an ellipsoid of revolution, a paraboloid of revolution, a hyperboloid of revolution.

10. A projector type headlight as claimed in claim 6, in which said upper beam projecting unit comprises:

a second concave reflector having an ellipsoidal light reflecting surface with first and second focuses, said second concave reflector being arranged below said first concave light reflector and integral therewith;

a second light source arranged behind said first light source and located on or at least near said first focus of said second concave reflector; and

a second converging lens arranged in front of said second concave reflector to pass therethrough light rays which have been emitted from said second light source and reflected by said second concave reflector, said second converging lens being positioned in such a manner that a focus thereof is placed near said second focus of said second concave reflector.

11. A projector type headlight as claimed in claim 10, in which an optical axis of said second concave reflector is somewhat inclined with respect to the optical axis of said first converging lens.

12. A projector type headlight as claimed in claim 10 further comprising a flat light reflector which is arranged in the vicinity of said second focus of said second concave reflector.

13. A projector type headlight as claimed in claim 6, further comprising:

means defining between said first and second concave light reflectors a given clearance;

an elongate curved light reflector arranged behind said first and second concave reflectors and extending along said given clearance to reflect the light rays emitted from said first and second light sources forward; and

an auxiliary lens integral with both said first converging lens and said corrugated lens, said auxiliary lens being arranged to pass therethrough said light rays from said elongate curved light reflector.