Uniform light source

• US 5,055,978 A
• Filed: 12/29/1989
• Issued: 10/08/1991
• Est. Priority Date: 12/29/1989
• Status: Expired due to Fees

• Current Assignee: GTE Products Corporation
• Original Assignee: GTE Products Corporation
• Inventors: Rogoff, Gerald L.
• Primary Examiner(s): Lazarus, Ira S.
• Assistant Examiner(s): Hagarman, Sue
• Application Number:
  US07/459,045
• Time in Patent Office: 648 Days
• Field of Search: 362/26, 362/31, 362/32
• US Class Current: 362/614
• CPC Class Codes: G02B 6/0031 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0046 Tapered light guide, e.g. wedge-shaped light guide
• CPC Class Codes: G09F 2013/1804 Achieving homogeneous illumination

Abstract

A light source in which a lamp aperture is arranged to illuminate a large panel provided with a reflective surface by having light rays from the aperture pass through a trough wherein such rays are changed so they are all substantially at angles greater than the critical angle necessary for total internal reflection. Light reflected from the panel is emitted through a window with the aid of light scatterers.

Claims

1. A light source comprising:

a lamp having an aperture for emission of light;

a transition member for receiving light that is emitted through the aperture of said lamp and for transmitting the light through an output thereof; and

a panel light emitter for receiving light from the output of said transition member, said panel light emitter including a light-emitting surface, scattering means for redirecting light through said light-emitting surface, and total internal reflection means for containing light within said panel light emitter except when said light is incident on said scattering means and is redirected by said scattering means through said light-emitting surface, said panel light emitter comprising a substantially transparent panel, the output of said transition member being optically coupled to an edge of said transparent panel, the aperture in said lamp having a width that is less than the thickness of said transparent panel, said transition member being tapered from the width of said aperture to the thickness of said panel.

2. A light source as defined in claim 1 wherein said scattering means comprises scatterers dispersed in the volume of said transparent panel.

3. A light source as defined in claim 1 wherein said scattering means comprises scatterers on a surface of said transparent panel.

4. A light source as defined in claim 1 wherein said lamp comprises a tubular fluorescent lamp.

5. A light source as defined in claim 1 wherein said transition member comprises a transparent material having reflective tapered surfaces, the dimensions of said transition member being selected such that the light transmitted through said transition member into said transparent panel undergoes total internal reflection on the flat surfaces of the transparent panel.

6. A light source as defined in claim 5 wherein said transition member is integral with said panel light emitter.

7. A light source comprising:

a lamp having an aperture for emission of light; and

a panel light emitter for receiving light emitted through the aperture of said lamp, said panel light emitter including a light-emitting surface, scattering means for redirecting light through said light-emitting surface, and total internal reflection means for containing light within said panel light emitter except when said light is incident on said scattering means and is redirected by said scattering means through said light-emitting surface, said panel light emitter comprising a substantially transparent panel and including a transition portion for receiving light that is emitted through the aperture of said lamp, the aperture in said lamp having a width that is less than the thickness of said transparent panel, said transition portion being tapered from the width of said aperture to the thickness of said transparent panel.

8. A light source as defined in claim 7 wherein said scattering means comprises scatterers dispersed in the volume of said transparent panel.

9. A light source as defined in claim 7 wherein said scattering means comprises scatterers on a surface of said transparent panel.

10. A light source as defined in claim 7 wherein said lamp comprises a tubular fluorescent lamp.

11. A light source as defined in claim 7 wherein said transition portion comprises a transparent material having reflective tapered surfaces, the dimensions of said transition portion being selected such that the light transmitted through said transition portion undergoes total internal reflection on the flat surfaces of the transparent panel.

12. A light source comprising:

a tubular lamp having an elongated aperture for emission of light;

a transition member for receiving light that is emitted through the aperture of said lamp and for transmitting the light through an output of the transition member; and

a flat panel light emitter including an edge for receiving light from the output of the transition member, a light-emitting surface, scattering means for redirecting light through said light-emitting surface, and total internal reflection means for containing light within said panel light emitter except when said light is incident on said scattering means and is redirected by said scattering means through said light-emitting surface.

13. A light source as defined in claim 12 wherein said scattering means comprises scatterers dispersed in the volume of said transparent panel.

14. A light source as defined in claim 12 wherein said scattering means comprises scatterers on a surface of said transparent panel.

15. A light source as defined in claim 12 wherein said panel light emitter comprises a substantially transparent panel having flat surfaces.

16. A light source as defined in claim 15 wherein the width of the aperture in said lamp is less than the thickness of said transparent panel and wherein said transition member is tapered from the width of said aperture to the thickness of said panel.

17. A light source as defined in claim 16 wherein said transition member comprises a transparent material having reflective tapered surfaces, the dimensions of said transition member being selected such that the light transmitted through said transition member into said transparent panel undergoes total internal reflection on the flat surfaces of the transparent panel.