Lighting device with light sources positioned near the bottom surface of a waveguide

Patent metadata

Field	Value
Publication number	US-9322973-B2
Application number	US-50391509-A
Country	US
Kind code	B2
Filing date	Jul 16, 2009
Priority date	Jul 16, 2009
Publication date	Apr 26, 2016
Grant date	Apr 26, 2016

Abstract

A device according to embodiments of the invention includes a waveguide, typically formed from a first section of transparent material. A light source is disposed proximate a bottom surface of the waveguide. The light source comprises a semiconductor light emitting diode and a second section of transparent material disposed between the semiconductor light emitting diode and the waveguide. Sidewalls of the second section of transparent material are reflective. A surface to be illuminated is disposed proximate a top surface of the waveguide. In some embodiments, an edge of the waveguide is curved.

First claim

What is being claimed is:

1. A device comprising:
a waveguide comprising a first section of transparent material;
a light source disposed proximate a bottom surface of the waveguide, the light source comprising:
a base element upon which at least one semiconductor light emitting diode is situated;
sidewalls that extend from the base element to the waveguide and form a cavity between the semiconductor light emitting device and the light guide; and
a second section of transparent material disposed within the cavity; and

a surface to be illuminated proximate a top surface of the waveguide;
wherein:
the sidewalls are reflective, and
the semiconductor light emitting diode includes a photonic crystal configured such that at least half of energy emitted by the semiconductor light emitting diode is emitted at angles >45° relative to a normal to a top surface of the semiconductor light emitting diode.

2. The device of claim 1 wherein a reflective material is disposed on the sidewalls of the second section of transparent material.

3. The device of claim 2 wherein the reflective material comprises TiO 2 disposed in a transparent binder material.

4. The device of claim 1 wherein:
the semiconductor light emitting diode is aligned with a first portion of the bottom of the second section of transparent material; and
a second portion of the bottom of the second section of transparent material adjacent the first portion is reflective.

5. The device of claim 4 wherein a reflective material is disposed on the second portion of the bottom of the second section of transparent material.

6. The device of claim 1 wherein the second section of transparent material is one of glass and silicone.

7. The device of claim 1 wherein an edge of the waveguide is shaped to direct light toward a portion of the waveguide underlying the surface to be illuminated.

8. The device of claim 1 wherein an edge of the waveguide is curved.

9. The device of claim 1 wherein an edge of the waveguide is shaped to cause total internal reflection of light incident on the edge.

10. The device of claim 1 further comprising a dichroic filter disposed between the waveguide and the second section of transparent material.

11. The device of claim 1 further comprising a wavelength converting material disposed between the surface to be illuminated and the semiconductor light emitting diode.

12. The device of claim 1 wherein the second section of transparent material has a length greater than a length of the semiconductor light emitting diode.

13. The device of claim 1 wherein the semiconductor light emitting diode comprises:
a sapphire growth substrate; and
a reflective coating disposed on the sapphire growth substrate.

Assignees

• Bierhuizen Serge J
• Koninkl Philips Nv
• Lumileds Llc

Inventors

• Bierhuizen Serge J

Classifications

• H10H20/0363

  of optical field-shaping means · CPC title

• H10H20/0362

  of encapsulations · CPC title

• H10H20/036

  of packages · CPC title

• H10H20/8506

  Containers · CPC title

• H10H20/856

  Reflecting means · CPC title