Signal lamp composed of light emitting diodes for vehicle

• US 5,093,768 A
• Filed: 10/23/1990
• Issued: 03/03/1992
• Est. Priority Date: 10/27/1989
• Status: Expired due to Term

• Current Assignee: Stanley Electric Company Limited
• Original Assignee: Stanley Electric Company Limited
• Inventors: Ohe, Kouji
• Primary Examiner(s): Lazarus, Ira S.
• Assistant Examiner(s): Hagarman, Sue
• Application Number:
  US07/601,514
• Time in Patent Office: 497 Days
• Field of Search: 362/227, 362/237, 362/240, 362/241, 362/297, 362/346, 362/800, 313/500, 313/110, 313/114, 313/512
• US Class Current: 362/241
• CPC Class Codes: F21S 43/14 Light emitting diodes [LED]
• CPC Class Codes: Y10S 362/80 Light emitting diode

Abstract

An improved signal lamp for a vehicle is composed of a plurality of dome type light emitting diodes and a plurality of reflective mirrors arranged corresponding to the light emitting diodes. Each of the reflective mirrors is designed in the shape of a rotational parabolic surface whose focus is located at the position coincident to the foremost end of the corresponding light emitting diode or at the position in the vicinity of the foremost end of the corresponding light emitting diode. The rotational parabolic surface is configured such that a virtual light source appearing on each light emitting diode is located at the position coincident with the focus of the corresponding reflective mirror or at the position in the vicinity of the focus of the corresponding reflective mirror. Each light emitting diode chip is sealably received in a transparent cylindrical case molded of synthetic resin such that a large part of light generated by the light emitting diode chip is emitted directly from the light emitting diode chip so as to allow it to be radiated to the outside through the lens portion at a radiating angle ranging from 10° to 12° as measured from the optical axis.

Claims

1. In a signal lamp for a vehicle composed of a plurality of dome-type light emitting diodes and a plurality of reflective mirrors arranged corresponding to said light emitting diodes, each comprising a diode chip encapsulated in a transparent body having a generally cylindrical shape and terminating in a hemispheric-shaped top, said chip being arranged to lie substantially along the longitudinal axis of said transparent body at a spaced distance from the intersection of the longitudinal axis and the periphery of said hemispheric-shaped top, and a lens positioned to pass light rays directly from said light emitting diodes and reflected from said reflective mirrors, the improvement wherein each of said reflective mirrors is designed in the shape of a parabolic surface of revolution whose axis of revolution is substantially coincident with the longitudinal axis of its associated light emitting diode and whose focus is located substantially at a position coincident with said intersection or a position in the vicinity of said intersection to cause more uniform distribution of light rays from each light emitting diode over the surface of the reflective mirror associated therewith.

2. The signal lamp as claimed in claim 1, wherein said rotational parabolic surface is contoured such that a virtual light source appearing on each light emitting diode is located at a position substantially coincident with the focus of the corresponding reflective mirror or at the position in the vicinity of the focus of the corresponding reflective mirror.

3. The signal light as claimed in claim 1, wherein each light emitting diode is sealably received in a transparent cylindrical case molded of synthetic resin such that a large part of light generated by said light emitting diode chip is emitted directly from the light emitting diode chip so as to allow it to be radiated to the outside through a lens portion at a radiating angle ranging from 10°

to 12°

as measured from an optical axis.

4. The signal lamp as claimed in claim 3, wherein each light emitting diode chip is sealably received in said transparent body which is contoured such that another part of the light generated by said light emitted diode is reflected at a portion of the hemispheric-shaped top peripheral to the cylindrical portion of said transparent body and the reflected light is then emitted to the outside of the transparent body and toward the parabolic surface of the reflective mirror via diffraction by the cylindrical portion of the transparent body.

5. The signal light as claimed in claim 3 wherein each light emitting diode is sealably received in said transparent body having a periphery which is contoured such that a portion of the light generated by said light emitting diode is reflected by a portion of the lens which is peripheral to the cylindrical portion of said transparent body and the reflected light is then emitted to the outside of the transparent body and toward the parabolic surface of the reflective mirror via diffraction by said transparent body.

6. In a signal lamp for a vehicle comprising a plurality of dome-type light emitting diodes and a plurality of reflective mirrors each associated with one of said light emitting diodes, the improvement wherein each of said dome-type light emitting diodes comprises a light emitting diode element sealably received within a substantially cylindrical shaped transparent body molded of a synthetic resin, said cylindrical shaped body terminating in a dome-shaped end;

said light emitting diode element being positioned substantially along the longitudinal axis of said transparent body a spaced distance beneath the intersection of said longitudinal axis and the dome-shaped end; and

each of said reflective mirrors having the shape of a parabolic surface or revolution whose axis of revolution is substantially coincident with the longitudinal axis of said transparent body an whose focus is located substantially at a position coincident with the intersection of said longitudinal axis and the dome shaped end of its associated light emitting diode.

7. The signal lamp of claim 6 wherein the parabolic surface of rotation is contoured such that a virtual light source appearing at its associated light emitting diode is located at a position substantially coincident with the focus of the corresponding reflective mirror.

8. In a signal lamp for a vehicle comprising a plurality of dome-type light emitting diodes and a plurality of reflective mirrors each associated with one of said light emitting diodes, the improvement wherein each of said dome-type light emitting diodes comprises a light emitting diode element sealably received within a substantially cylindrical shaped transparent body molded of a synthetic resin, said cylindrical shaped body terminating in a dome-shaped end;

said light emitting diode element being positioned substantially along the longitudinal axis of said transparent body a spaced distance beneath the intersection of said longitudinal axis and the dome-shaped end; and

each of said reflective mirrors having the shape of a parabolic surface or revolution whose axis of revolution is substantially coincident the longitudinal axis of said transparent body and whose focus is located substantially in the vicinity of the intersection of said longitudinal axis and the dome shaped end of said light emitting diode.

9. The signal lamp of claim 8 wherein the parabolic surface of rotation is contoured such that a virtual light source appearing at its associated light emitting diode is located at a position in the vicinity of the focus of the corresponding reflective mirror.