Plasma discharge lamp

• US 5,618,102 A
• Filed: 06/07/1995
• Issued: 04/08/1997
• Est. Priority Date: 06/07/1995
• Status: Expired due to Fees

• Current Assignee: ADAC Plastics Incorporated (ADAC Automotive, Inc.)
• Original Assignee: ADAC Plastics Incorporated (ADAC Automotive, Inc.)
• Inventors: Ferrell, Richard M.
• Primary Examiner(s): Lazarus, Ira S.
• Assistant Examiner(s): Sember, Thomas M.
• Application Number:
  US08/475,225
• Time in Patent Office: 671 Days
• Field of Search: 362/61, 362/298, 362/302, 362/303, 362/304, 362/305, 362/346, 362/310, 362/307, 362/308, 362/299, 362/300, 362/263, 362/265, 362/80
• US Class Current: 362/516
• CPC Class Codes: F21S 41/173 Fluorescent light sources
• CPC Class Codes: F21S 41/28 Cover glass
• 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 41/365 successively reflecting the light
• CPC Class Codes: F21V 25/00 Safety devices structurally associated with lighting devices gas- tight or water-tight arrangements F21V31/00; in general F16P; protective circuit arrangements per se H02H7/00

Abstract

A lamp especially designed for use with plasma discharge light sources such as neon tubes. The lamp provides secondary reflective surfaces to ensure that each ray of light leaving the neon tube strikes at least one metallic reflective surface so as to reduce the troublesome RF characteristic of the neon tube and reduce the interference with other electronic equipment on board the vehicle.

Claims

1. A lamp comprising:

a reflector defining a reflective surface having a focal point and a central axis passing through the focal point;

a cover coacting with the reflector to define a lamp chamber;

a plasma discharge light source positioned in the chamber at the focal point and including an elongated tube positioned transversely of the central axis and passing through the focal point; and

a deflector device having a reflective surface located in the chamber between the light source and the cover in a position to intersect and redirect light rays emanating from the tube prior to passage of the light rays through the cover, the deflector operating to ensure that all light rays emanating from the tube are reflected off at least one reflective surface before passing through the cover to thereby reduce the RF characteristics of the light rays.

2. A lamp according to claim 1 wherein the reflector reflective surface has an elliptic configuration.

3. A lamp according to claim 1 wherein the deflector reflective surface has a parabolic configuration.

4. A lamp according to claim 1 wherein the elongated tube comprises a neon tube.

5. A lamp according to claim 1 wherein the lamp comprises a headlamp for a motor vehicle.

6. A lamp according to claim 1 wherein:

,

the reflector has an elliptic configuration defining first and second focal points; and

the light source is positioned at the first focal point.

7. A lamp according to claim 6 wherein:

the deflector device presents a parabolic reflective surface; and

the second focal point of the reflector constitutes the focus of the parabolic surface.

8. A lamp according to claim 6 wherein the deflector device is positioned between the first and second focal points.

9. A lamp according to claim 8 wherein the deflector device defines a reflective surface configured such that light rays reflected thereby are thereafter reflected by the elliptic reflective surface of the reflector and thereafter pass through the second focal point.

10. A lamp according to claim 9 wherein the cover comprises a lens operative to collimate the light rays after they have passed through the second focal point whereby to project a beam of light from the lamp.

11. A method of reducing the RF characteristics of a lamp having a reflector defining a reflective surface having a focal point, a cover coacting with the reflector to define a lamp chamber, and a plasma discharge light source positioned in the chamber at the focal point, characterized in that the method includes placing a deflector device having a reflective surface in the chamber between the light source and the cover in a position to intercept and redirect light rays emanating from the light source prior to passage of the light rays through the cover so that each light ray emanating from the light source strikes at least one reflective surface before passing out of the lamp chamber through the cover whereby to reduce the RF characteristics of the light rays.

12. A method according to claim 11 wherein:

the reflector reflective surface has an elliptic configuration defining first and second focal points; and

the deflector device is placed in the chamber between the first and second focal points.

13. A method according to claim 11 wherein:

the reflector reflective surface has an elliptic configuration defining first and second focal points;

the light source is positioned at the first focal point; and

the deflector reflective surface comprises a parabolic surface having its focus coinciding with the second focal point.

14. A lamp comprising:

a reflector defining an elliptic reflective surface defining first and second focal points;

a cover coacting with the reflector to define a lamp chamber;

a plasma discharge light source positioned in the chamber at the first focal point; and

a deflector device presenting a parabolic surface having its covexity facing the first focal point and located in the chamber between the light source and the cover and between the first and second focal points in a position to intersect and redirect light rays emanating from the light source prior to passage of the light rays through the cover.