Slim waveguide coupling apparatus and method

• US 8,297,786 B2
• Filed: 03/02/2010
• Issued: 10/30/2012
• Est. Priority Date: 07/10/2008
• Status: Active Grant

• Current Assignee: Oree Advanced Illumination Solutions Ltd.
• Original Assignee: Oree, Inc.
• Inventors: Shani, Yosi, Kosburd, Tania, Arbiv, Dafna B.
• Primary Examiner(s): TSO, LAURA K
• Application Number:
  US12/715,880
• Publication Number:
  US 20100220484A1
• Time in Patent Office: 973 Days
• Field of Search: 362/247, 362/231, 362/97.3, 362/311.02
• US Class Current: 362/247
• CPC Class Codes: G02B 19/0028 refractive and reflective surfaces, e.g. non-imaging catadioptric systems
• CPC Class Codes: G02B 19/0061 the light source comprising a LED semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission H01L33/00
• CPC Class Codes: G02B 19/0066 in the form of an LED array
• CPC Class Codes: G02B 5/021 the diffusion taking place at the element's surface, e.g. by means of surface roughening or microprismatic structures
• CPC Class Codes: G02B 6/0018 Redirecting means on the surface of the light guide
• CPC Class Codes: G02B 6/002 by shaping at least a portion of the light guide, e.g. with collimating, focussing or diverging surfaces
• CPC Class Codes: G02B 6/0021 for housing at least a part of the light source, e.g. by forming holes or recesses
• CPC Class Codes: G02B 6/0025 Diffusing sheet or layer; Prismatic sheet or layer
• CPC Class Codes: G02B 6/0026 Wavelength selective element, sheet or layer, e.g. filter or grating
• CPC Class Codes: G02B 6/0031 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0035 provided on the surface of the light guide or in the bulk of it
• CPC Class Codes: G02B 6/0036 2-D arrangement of prisms, protrusions, indentations or roughened surfaces
• CPC Class Codes: G02B 6/0045 by shaping at least a portion of the light guide
• CPC Class Codes: G02B 6/0051 Diffusing sheet or layer
• CPC Class Codes: G02B 6/0055 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0061 to provide homogeneous light output intensity
• CPC Class Codes: G02B 6/0068 Arrangements of plural sources, e.g. multi-colour light sources
• CPC Class Codes: G02B 6/0076 Stacked arrangements of multiple light guides of the same or different cross-sectional area
• CPC Class Codes: G02B 6/009 of the light source in the package G02B6/0021 takes precedence

Abstract

In various embodiments, an illumination structure includes a discrete light source disposed proximate a bottom surface of a waveguide and below a depression in a top surface thereof. A top mirror may be disposed above the discrete light source to convert modes of light emitted from the discrete light source into trapped modes, thereby increasing the coupling efficiency of the illumination structure.

Claims

1. An illumination structure comprising:

a waveguide having a depression in a top surface thereof;

a discrete light source disposed proximate a bottom surface of the waveguide and below the depression; and

a top mirror disposed above the discrete light source, the top mirror comprising a conical mirror disposed over and at least substantially filling the depression.

2. The illumination structure of claim 1, further comprising an air gap disposed between the conical mirror and the depression.

3. The illumination structure of claim 1, further comprising a substantially flat mirror disposed over substantially all of the depression.

4. The illumination structure of claim 3, wherein the substantially flat mirror comprises at least one of a specular mirror, a diffusive reflector, a Fresnel reflector, or a diffractive optical element.

5. The illumination structure of claim 1, wherein a surface of the conical mirror proximate the waveguide comprises a reflective coating thereon.

6. The illumination structure of claim 1, further comprising an index-matching material disposed between the waveguide and the conical mirror.

7. The illumination structure of claim 6, wherein an index of refraction of the index-matching material is substantially equal to an index of refraction of the waveguide.

8. The illumination structure of claim 1, wherein a shape of the conical mirror is at least one of conical, parabolic, pyramidal, or prismatic.

9. The illumination structure of claim 1, wherein the conical mirror comprises a reflective metal.

10. The illumination structure of claim 9, wherein the reflective metal comprises at least one of aluminum or silver.

11. The illumination structure of claim 1, wherein the conical mirror comprises topaz or a polymer.

12. The illumination structure of claim 11, wherein the conical mirror comprises polymethyl methacrylate.

14. The illumination structure of claim 2, wherein a thickness of the air gap is selected from the range of approximately 10 μ

m to approximately 50 μ

m.

15. The illumination structure of claim 2, wherein a thickness of the air gap is less than approximately 10 μ

m.

16. The illumination structure of claim 2, wherein at least a portion of the air gap is filled with a filler material.

17. The illumination structure of claim 16, wherein the filler material is adhesive.

18. The illumination structure of claim 16, wherein an index of refraction of the filler material is less than an index of refraction of the waveguide.

19. The illumination structure of claim 16, wherein the filler material comprises silicone.

13. A method for coupling light emitted from a discrete light source to a waveguide, the method comprising:

emitting light from a discrete light source disposed within a waveguide; and

reflecting a portion of the emitted light from a top mirror disposed above a depression in a top surface of the waveguide, the depression being disposed above the discrete light source, so as to confine the reflected portion of the emitted light within the waveguide,

wherein the top mirror comprises a conical mirror substantially filling the depression, and the portion of the emitted light traverses an air gap between the depression and the top mirror before being reflected.