Semiconductor light source configured as a light tube

• US 20070263405A1
• Filed: 05/11/2006
• Published: 11/15/2007
• Est. Priority Date: 05/11/2006
• Status: Active Grant

• Current Assignee: Document Security Systems, Inc.
• Original Assignee: Avago Technologies ECBU IP Singapore Pte Limited (Broadcom, Inc.)
• Inventors: Lee, Sian, Ng, Kee
• Granted Patent: US 7,549,782 B2
• Time in Patent Office: Days
• US Class Current: 362/555
• CPC Class Codes: F21K 9/27 Retrofit light sources for lighting devices with two fittings for each light source, e.g. for substitution of fluorescent tubes
• CPC Class Codes: F21K 9/64 using wavelength conversion means distinct or spaced from the light-generating element, e.g. a remote phosphor layer
• CPC Class Codes: F21K 9/69 Details of refractors forming part of the light source
• CPC Class Codes: F21Y 2113/13 comprising an assembly of point-like light sources
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: G02B 6/0003 the light guides being doped with fluorescent agents
• CPC Class Codes: G02B 6/001 the light being emitted along at least a portion of the lateral surface of the fibre

Abstract

A tubular light source having a semiconductor light source and a tube is disclosed. The tube includes a transparent medium, the tube having a side tube surface, a center curve, one end surface, a length, and a maximum cross-sectional dimension. The tube includes scattering centers that cause light traveling in the tube to be reflected at angles such that the reflected light leaves the tube through the side tube surface. The semiconductor light source is positioned to emit light into the tube within a cone of angles such that the light will not leave the side tube surface in the absence of the scattering centers. The scattering centers can be dispersed in the transparent medium or located on the side tube surface. The transparent medium can be rigid or flexible.

Claims

1. A light source comprising:

a semiconductor light source;

a tube comprising a transparent medium, said tube having a side tube surface, a center curve, one end surface, a length, and a maximum cross-sectional dimension, said tube having scattering centers that cause light traveling in said tube to be reflected at angles such that said reflected light leaves said tube through said side tube surface;

said semiconductor light source being positioned to emit light into said tube within a cone of angles such that said light will not leave said side tube surface in the absence of said scattering centers, wherein said length is greater than 10 times said maximum cross-sectional dimension; and

wherein said scattering centers are dispersed in said transparent medium.

2. The light source of claim 1 wherein said end surface comprises a reflective material for reflecting light striking said end surface back into said tube.

5. The light source of claim 1 wherein said center curve comprises a portion of a circle.

6. The light source of claim 1 wherein said center curve comprises a straight line.

7. The light source of claim 1 wherein said transparent medium comprises an elastomeric material.

8. The light source of claim 1 wherein said semiconductor light source comprises an LED.

9. The light source of claim 1 wherein said semiconductor light source comprises a laser.

10. The light source of claim 1 wherein said scattering sources are dispersed such that said light leaving said side tube surface has a substantially uniform intensity as a function of position along said center curve.

11. The light source of claim 1 wherein said tube comprises first and second ends and wherein said semiconductor light source comprises a first light emitter that injects light into said first end and a second light emitter that injects light into said second end.

12. The light source of claim 1 wherein said tube comprises a phosphorescent or fluorescent material that converts light from said semiconductor light source to light having a different spectrum from that emitted by said semiconductor light source.

13. The light source of claim 12 wherein said phosphorescent or fluorescent material comprises first and second phosphors, said first phosphor being located at different locations from said second phosphor.

14. The light source of claim 12 wherein said phosphorescent or fluorescent material is located in said scattering centers.

15. The light source of claim 1 further comprising a controller that sets an intensity of light emitted by said semiconductor light source in response to an externally generated intensity control signal.

16. The light source of claim 15 wherein said controller controls the spectrum of light emitted from said semiconductor light source in response to an externally generated color control signal.

3-4. -4. (canceled)

17. A light source comprising:

a first semiconductor light source;

a first tube comprising a first transparent medium having a first side tube surface, and a first center curve, said first tube having scattering centers that cause light traveling in said first tube to be reflected at angles such that said reflected light leaves said first tube through said first side tube surface;

said first semiconductor light source being positioned to emit light into said first tube within a cone of angles such that said light will not leave said first side tube surface in the absence of said scattering centers;

a second semiconductor light source;

a second tube comprising a second transparent medium having a second side tube surface, and a second center curve, said second tube having scattering centers that cause light traveling in said second tube to be reflected at angles such that said reflected light leaves said second tube through said second side tube surface; and

said second semiconductor light source being positioned to emit light into said second tube within a cone of angles such that said light will not leave said second side tube surface in the absence of said scattering centers, wherein said first and second center curves are intertwined with one another.

18. The light source of claim 17 wherein said first and second light sources emit light having different spectra.

19. The light source of claim 17 wherein one of said first and second transparent media comprises a flexible material.