Illumination device

• US 8,152,339 B2
• Filed: 05/01/2008
• Issued: 04/10/2012
• Est. Priority Date: 05/01/2007
• Status: Active Grant

• Current Assignee: Morgan Innovation Incorporated
• Original Assignee: Morgan Solar Inc.
• Inventors: Morgan, John Paul
• Primary Examiner(s): Lee, Jong-Suk (James)
• Assistant Examiner(s): Makiya, David J
• Application Number:
  US12/597,648
• Publication Number:
  US 20100202142A1
• Time in Patent Office: 1,440 Days
• Field of Search: 362/336, 362/606, 362/616, 362/617
• US Class Current: 362/336
• CPC Class Codes: F21S 11/00 Non-electric lighting devices or systems using daylight roofs with sky-light opening E04D13/03; sun blinds for windows with means for redirecting light onto ceiling of a room E06B9/00; hybrid lighting devices combining artificial and natural light F21S19/00; solar heat collectors F24S; solar cells or solar cell modules H01L31/00
• CPC Class Codes: G02B 19/0004 characterised by the optical means employed
• CPC Class Codes: G02B 19/0019 having reflective surfaces only (e.g. louvre systems, systems with multiple planar reflectors)
• CPC Class Codes: G02B 19/0028 refractive and reflective surfaces, e.g. non-imaging catadioptric systems
• CPC Class Codes: G02B 6/0011 the light guides being planar or of plate-like form
• CPC Class Codes: G02B 6/0038 Linear indentations or grooves, e.g. arc-shaped grooves or meandering grooves, extending over the full length or width of the light guide
• CPC Class Codes: G02B 6/0078 Side-by-side arrangements, e.g. for large area displays
• CPC Class Codes: H01L 31/02327 the optical elements being integrated or being directly associated to the device, e.g. back reflectors optical coatings H01L31/0216
• CPC Class Codes: H01L 31/0547 comprising light concentrating means of the reflecting type, e.g. parabolic mirrors, concentrators using total internal reflection
• CPC Class Codes: Y02E 10/52 PV systems with concentrators
• CPC Class Codes: Y10T 29/49826 Assembling or joining

Abstract

An illumination device having an optical waveguide stage to which is optically coupled a light-projecting stage. The illumination device accepts light from a small isotropic light source such as a light emitting diode or a bulb coupled to the optical waveguide stage. The illumination device spreads the light over a wide area while also collimating it to form a beam. The light-projecting stage and the optical waveguide stage are made of thin slabs of optically transmissive material.

Claims

1. An illumination device based on multiple total internal reflections, comprising:

a light-projecting slab having a plurality of injection faces and an output surface, the light-projecting slab further including a plurality of optical elements located optically between the plurality of injection faces and the output surface, each optical element being separated from adjacent elements by a material having an index of refraction lower than that of a material of the light-projecting slab, wherein each optical element includes a curved reflection surface, in cross-section the curve of the reflection surface being at least substantially parabolic and having an axis of symmetry and a focal point lying at least substantially along the axis of symmetry;

an injection molded wedge-shaped optical waveguide slab separate from and optically coupled to the light-projecting slab, the optical waveguide slab having a first surface that is a reflector operating by total internal reflection in conjunction with a plurality of reflectors opposed to the first surface, the optical waveguide slab further including a plurality of exit faces adjacent the injection faces of the light-projecting slab, the plurality of injection faces and the plurality of exit faces forming a plurality of optical input apertures located between the optical waveguide slab and the light-projecting slab, the optical waveguide slab further including an input surface to receive light from a light source, the waveguide slab guiding the light from the input surface towards the optical input apertures through multiple total internal reflections,

the optical elements of the light-projecting slab directing the light from each input aperture to the output surface wherefrom the light exits the illumination device as a plurality of beams, each beam having been reflected off the reflection surface of one of the optical elements via total internal reflection, in cross-section the curves of the reflection surfaces of the optical elements each having a shape such that light passing generally through that curve'"'"'s focal point and reflecting off the reflection surface which forms that curve has an output direction generally parallel to the axis of symmetry of that curve of that reflection surface; and

the light source being optically coupled to the input surface of the optical waveguide slab.

2. The device as claimed in claim 1 wherein the plurality of reflectors of the waveguide slab are substantially parallel to the first surface of the waveguide slab.

3. The device as claimed in claim 1 wherein adjacent reflectors of the waveguide slab have one of the exit faces located therebetween.

4. The device as claimed in claim 1 wherein the input surface of the waveguide slab has a light input area and the output surface of the light-projecting slab has a light emitting area, the light input area being smaller than the light emitting area.

5. The device as claimed in claim 1 wherein the optical elements are located along substantially parallel lines.

6. The device as claimed in claim 1 wherein:

the optical elements are annular and are located along substantially concentric circle arcs; and

the input surface is shaped as a circle arc substantially concentric with the optical elements.

7. The device as claimed in claim 1 wherein the light exits the light-projecting slab as a substantially collimated beam.

8. The device as claimed in claim 1 wherein the output surface of the light-projecting slab is continuous after the plurality of optical elements.

9. The device as claimed in claim 7 wherein the light source is a first light source and the substantially collimated beam of light is a first substantially collimated beam of light, the device further comprising a second light source optically coupled to the waveguide to generate a second beam of light exiting the light-projecting slab as a second substantially collimated beam of light, the second substantially collimated beam of light exiting the light projecting slab at a different angle relative to the first substantially collimated beam of light.

10. The device as claimed in claim 1, wherein, in cross-section, the curve of each reflection surface is parabolic.

11. The device as claimed in claim 10 wherein, in cross-section, the focal point of the curve of each reflection surface lies directly on the axis of symmetry of that curve.

12. The device as claimed in claim 11 wherein, in cross-section, the focal point of the curve of each reflection surface lies directly on the axis of symmetry of that curve.

13. The device as claimed in claim 1 wherein each of the optical input apertures is sized and positioned such that, in cross-section, substantially all of the light passing through that optical input aperture passes through the focal point of the curve of the reflection surface associated with that optical input aperture.

14. The device as claimed in claim 1 wherein each of the optical input apertures is sized and positioned such that, in cross-section less than substantially all of the light passing through that optical input aperture passes through the focal point of the curve of the reflection surface associated with that optical input aperture.

15. The device as claimed in claim 1 wherein, in cross-section all of the curves of the reflection surfaces are identical.

16. The device as claimed in claim 1 wherein

the curved reflection surface of each of the optical elements of the light-projecting slab is a single uncoated curved reflection surface,

the light projection slab is injection-molded, and

the optical waveguide slab is injection-molded.

17. The device as claimed in claim 1 wherein the light source is a light emitting diode.

18. The device as claimed in claim 1 wherein the optical elements are annular and are located along substantially concentric circles;

and the input surface is shaped as a circle substantially concentric with the optical elements.

19. The device as claimed in claim 6 wherein the light-projection slab has a circular circumference, and the concentric circle arcs along which the optical elements are located are eccentric with the circular circumference of the light-projection slab.

20. The device as claimed in claim 1, wherein the output surface of the light-projection slab includes a plurality of lenses to cause the beams to exiting the output surface to diverge in at least one plane.