Vehicle lamp

• US 5,727,874 A
• Filed: 07/26/1996
• Issued: 03/17/1998
• Est. Priority Date: 07/28/1995
• Status: Expired due to Fees

• Current Assignee: Koito Manufacturing Company Limited
• Original Assignee: Koito Manufacturing Company Limited
• Inventors: Maeda, Masahiro, Yamamoto, Norimasa
• Primary Examiner(s): CARIASO, ALAN B
• Application Number:
  US08/686,521
• Time in Patent Office: 599 Days
• Field of Search: 362/61, 362/80, 362/215, 362/297, 362/304, 362/305, 362/308, 362/309, 362/332, 362/326, 362/346, 362/348
• US Class Current: 362/305
• CPC Class Codes: F21S 41/323 the reflector having two perpendicular cross sections having regular geometrical curves of a distinct nature
• CPC Class Codes: F21S 41/337 the reflector having a structured surface, e.g. with facets or corrugations
• CPC Class Codes: F21S 43/30 characterised by reflectors
• CPC Class Codes: F21S 43/40 characterised by the combination of reflectors and refractors

Abstract

A vehicle lamp includes a reflection mirror, a front lens, and a light source arranged between the reflection mirror and the front lens in such a manner that the central axis of the light source is perpendicular to the principal optical axis. The reflection mirror is composed of a reflection surface having a large number of reflection steps which are defined by portions of paraboloids of revolution and are disposed between adjacent ones of lines of intersection obtained between a group of the paraboloids of revolution having different focal distances and a fundamental reflection surface of the reflection surface. Each reflection step is arranged to be extended substantially in the vertical direction, and square lens steps are formed on the front lens. Due to the foregoing, an arrangement tendency with respect to a set of projected images of the light source formed by the reflection step is matched with a section of the lens step on the front lens.

Claims

1. A vehicle lamp comprising:

a reflection mirror having a principal optical axis and a reflection surface comprising a plurality of reflection steps, said steps being defined by portions of respective paraboloids of revolution and disposed between adjacent ones of lines of intersection, each said lines of intersection being obtained where a respective one of a group of said paraboloids of revolution having different focal distances meets a basic reflection surface;

a front lens arranged in front of said reflection mirror; and

a light source arranged on said principal optical axis of said reflection mirror so that a central axis of said light source is arranged to be perpendicular to said principal optical axis of said reflection mirror;

wherein said reflection steps are formed into longitudinal stripe-shapes in the vertical direction, when viewed in the direction of said principal optical axis of said reflection mirror, and

wherein said lens steps are also formed in square regions on said front lens.

2. A vehicle lamp as recited in claim 1, wherein said light source comprises a filament and said reflection steps project a plurality of filament images.

3. A vehicle lamp as recited in claim 2, wherein the projection of each said filament images varies in imerse relation to a distance of the filament to the reflection point.

4. A vehicle lamp as recited in claim 2, wherein at least one filament image has a central axis disposed in the longitudinal direction and at least one central axis of said images extends in a substantially vertical direction.

5. A vehicle lamp as recited in claim 4 wherein said central axis of said at least one filament image in the longitudinal direction is inclined with respect to the central axis of the filament image in the longitudinal direction.

6. A vehicle lamp as recited in claim 4 wherein said filament image in said longitudinal direction is disposed at a position close to an end portion of the filament image in the vertical direction.

7. A vehicle lamp as recited in claim 2, wherein the overall shape of said filament images form a projection pattern that extends in the substantially vertical direction.

8. A vehicle lamp as recited in claim 7, wherein said projection pattern is shaped to match said lens steps formed in the square regions on said front lens.

9. A vehicle lamp as recited in claim 2, wherein said lens step diffuses said filament image in one of a longitudinal direction and a direction perpendicular to said longitudinal direction.

10. A vehicle lamp as recited in claim 1, wherein a shape of the cross-section of the center of the reflection surface in the horizontal direction taken on a vertical surface including the principal optical axis of the reflection mirror, is parabolic.

11. A vehicle lamp as recited in claim 1, wherein said lens steps are assembled into a grid-shaped region when a view is taken from the front.

12. A vehicle lamp as recited in claim 8 wherein a plurality of said grid-shaped regions comprise fish-eye lenses.