Lighting unit for vehicle headlamp including convex lens arranged between light source and shade

• US 7,878,695 B2
• Filed: 05/16/2008
• Issued: 02/01/2011
• Est. Priority Date: 05/17/2007
• Status: Active Grant

• Current Assignee: Koito Manufacturing Company Limited
• Original Assignee: Koito Manufacturing Company Limited
• Inventors: Ishida, Hiroyuki
• Primary Examiner(s): Negron; Ismael
• Application Number:
  US12/121,937
• Publication Number:
  US 20080285297A1
• Time in Patent Office: 991 Days
• Field of Search: 362/507, 362/539, 362/545, 362/547, 362/296.01, 362/307, 362/309, 362/327, 362/329
• US Class Current: 362/539
• CPC Class Codes: F21S 41/143 the main emission direction of the LED being parallel to the optical axis of the illuminating device
• CPC Class Codes: F21S 41/155 Surface emitters, e.g. organic light emitting diodes [OLED]
• CPC Class Codes: F21S 41/255 Lenses with a front view of circular or truncated circular outline
• CPC Class Codes: F21S 41/322 the reflector using total internal reflection
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]

Abstract

A lighting unit with a projection lens, a light source, a reflector, a shade, and a convex lens. The projection lens is arranged on an optical axis extending in a longitudinal direction of a vehicle. The light source is arranged on a rear side of a rear side focal point of the projection lens. The reflector reflects forward light from the light source toward the optical axis. An upper end edge of the shade passes through a vicinity of the rear side focal point. The shade shields part of a reflected light from the reflector. The convex lens is arranged between the light source and the shade, and converges light from the light source into the vicinity of the upper end edge of the shade.

Claims

1. A lighting unit for a vehicle headlamp, comprising:

a projection lens arranged on an optical axis extending in a longitudinal direction of a vehicle;

a light source arranged on a rear side of a rear side focal point of the projection lens;

a reflector configured to reflect forward a light from the light source toward the optical axis;

a shade arranged such that an upper end edge of the shade passes through a vicinity of the rear side focal point and configured to shield a part of a reflected light from the reflector; and

a convex lens arranged between the light source and the shade and configured to converge the light from the light source into the vicinity of the upper end edge of the shade;

wherein the reflector is arranged to cover the light source and the convex lens from a top side, and

an additional reflector configured to reflect the light from the light source to the convex lens and arranged below the light source.

2. The lighting unit according to claim 1, wherein the reflector is formed of a translucent member that is formed integrally with the convex lens, and

the reflector includes:

an inner peripheral side surface that extends backward from an outer peripheral edge of a rear side surface of the convex lens;

an outer peripheral side surface for internal-reflecting forward the light of the light source incident from the inner peripheral side surface by virtue of a total reflection; and

a front side surface for emitting a reflected light from the outer peripheral side surface forward.

3. The lighting unit according to claim 1, wherein the light source comprises a light emitting chip of a light emitting element that is arranged to direct forward.

4. The lighting unit according to claim 3, wherein the light emitting element is supported by a metal supporting plate extending along a vertical plane intersecting orthogonally with the optical axis, and

a plurality of radiating fins is formed on a rear surface of the supporting plate.