Light emitting diode illumination system

• US 9,574,722 B2
• Filed: 05/27/2015
• Issued: 02/21/2017
• Est. Priority Date: 08/06/2007
• Status: Active Grant

• Current Assignee: Lumencor, Inc.
• Original Assignee: Lumencor, Inc.
• Inventors: Brukilacchio, Thomas J.
• Primary Examiner(s): Ton, Tri T
• Application Number:
  US14/723,267
• Publication Number:
  US 20150276153A1
• Time in Patent Office: 636 Days
• Field of Search: 356/239.2, 356/239.4, 356/239.6, 356/240.1, 356/241.1, 356/241.3, 356/241.5, 356/241.6, 356/44, 356402-420, 356432-448, 356 43- 50, 356/440
• US Class Current: 1/1
• CPC Class Codes: A61B 1/00163 Optical arrangements A61B1/002, A61B1/06 take precedence
• CPC Class Codes: A61B 1/0653 with wavelength conversion
• CPC Class Codes: A61B 1/0669 at proximal end of an endoscope
• CPC Class Codes: A61B 1/0684 using light emitting diodes [LED]
• CPC Class Codes: A61N 2005/005 for cooling the radiator
• CPC Class Codes: A61N 2005/0652 Arrays of diodes
• CPC Class Codes: A61N 5/062 Photodynamic therapy, i.e. excitation of an agent
• CPC Class Codes: F21K 9/60 Optical arrangements integrated in the light source, e.g. for improving the colour rendering index or the light extraction
• CPC Class Codes: F21K 9/61 using light guides
• 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: F21V 13/04 the elements being reflectors and refractors for vehicle rear lights F21S43/40
• CPC Class Codes: F21V 13/08 the elements being filters or photoluminescent elements and reflectors
• CPC Class Codes: F21V 13/14 the elements being filters or photoluminescent elements, reflectors and refractors
• CPC Class Codes: F21V 29/60 characterised by the use of a forced flow of gas, e.g. air
• CPC Class Codes: F21V 29/70 characterised by passive heat-dissipating elements, e.g. heat-sinks
• CPC Class Codes: F21V 5/008 Combination of two or more successive refractors along an optical axis
• CPC Class Codes: F21V 7/0066 specially adapted to cooperate with point like light sources; specially adapted to cooperate with light sources the shape of which is unspecified F21V7/16 - F21V7/30 take precedence
• CPC Class Codes: F21V 9/30 Elements containing photoluminescent material distinct from or spaced from the light source shades F21V1/17; globes, bowls or cover glasses F21V3/08, F21V3/12; refractors F21V5/10; reflectors F21V7/26, F21V7/30; elements with provision for controlling the spectral properties or intensity F21V9/40
• CPC Class Codes: F21W 2131/205 for operating theatres
• CPC Class Codes: F21W 2131/40 Lighting for industrial, commercial, recreational or military use
• CPC Class Codes: F21Y 2105/00 : Planar light sources
• CPC Class Codes: F21Y 2113/00 : Combination of light sources
• 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: F21Y 2115/30 : Semiconductor lasers
• CPC Class Codes: G01N 2021/6419 : Excitation at two or more wavelengths
• CPC Class Codes: G01N 2021/6482 : Sample cells, cuvettes
• CPC Class Codes: G01N 21/64 : Fluorescence; Phosphorescence
• CPC Class Codes: G01N 2201/0627 : Use of several LED's for spectral resolution
• CPC Class Codes: G02B 23/2469 : using optical fibres
• CPC Class Codes: G02B 27/0994 : Fibers, light pipes optical fibers per se G02B6/02
• CPC Class Codes: G02B 27/1006 : for splitting or combining different wavelengths G02B27/1086, G02B27/141 take precedence
• CPC Class Codes: G02B 27/143 : using macroscopically faceted or segmented reflective surfaces
• CPC Class Codes: G02B 27/145 : having sequential partially reflecting surfaces
• CPC Class Codes: G02B 6/0006 : Coupling light into the fibre in general G02B6/4298

Abstract

In various embodiments of the invention, a unique construction for Light Emitting Diodes (LEDs) with at least one luminescent rod and extracting optical elements used to generate a variety of high brightness light sources with different emission spectra. In an embodiment of the invention, forced air cooling is used to cool the luminescent rod. In an embodiment of the invention, totally internal reflected light can be redirected outward and refocused. In another embodiment of the invention, light emitted by the luminescent rod is out-coupled for use in a variety of applications.

Claims

1. An illumination system comprising:

a first light source comprising a plurality of emitters of excitation light of an excitation color and a luminescent material positioned to receive the excitation light from all of the plurality of emitters of excitation light and emit light of a first color different than the excitation color whereby the first light source outputs a first light beam of said first color;

a second light source, wherein the second light source includes a Light Emitting Diode (LED), wherein the second light source emits a second light beam of a second color different than the first color;

a third light source, wherein the third light source includes another Light Emitting Diode (LED), wherein the third light source emits a third light beam of a third color different than the first color and second color;

a plurality of reflective optical components positioned to combine the first light beam of the first color, the second light beam of the second color, the third light beam of the third color, on a main optical axis of the illumination system to generate a beam of white light; and

an output system positioned to receive said beam of white light and configured to focus said beam of white light into a light guide.

2. The illumination system of claim 1, wherein the first light beam of said first color has a greater optical power and a greater optical power per unit area than the excitation light emitted by each of said plurality of emitters of excitation light individually.

3. The illumination system of claim 2, further comprising:

an optical concentrator configured to convert said first light emitted by said luminescent material to an area and solid angle suitable for generating the first light beam of said first color while substantially preserving etendue.

4. The illumination system of claim 3, wherein the optical concentrator is tapered such it has an output surface having an area larger than an optical output surface of the luminescent material.

5. The illumination system of claim 4, wherein the optical concentrator is bonded to the luminescent material of the first light source.

6. The illumination system of claim 5, wherein the optical concentrator comprises one of a compound parabolic concentrator (CPC), compound elliptical concentrator (CEC), and a compound hyperbolic concentrator (CHC).

7. The illumination system of claim 3, further comprising

a second optical concentrator adjacent the Light Emitting Diode (LED) of the second light source for forming the second light beam;

and

a third optical concentrator adjacent the another Light Emitting Diode (LED) of the third light source for forming the third light beam.

8. The illumination system of claim 1, wherein said beam of white light has an optical power of at least 2000 lumens.

9. The illumination system of claim 1, wherein said luminescent material has an optical output surface of approximately 1 mm squared.

10. The illumination system of claim 1, wherein the beam of white light has a color rendering index (CRI) of at least 85.

11. The illumination system of claim 1, wherein the excitation color is blue, the first color is green, the second color is blue, and the third color is red.

12. The illumination system of claim 1, further comprising a cooling system which provides an air flow to dissipate heat from the luminescent material.

13. The illumination system of claim 1, further comprising:

a cooling system which provides an air flow to dissipate heat from the luminescent material; and

a heatsink for cooling the plurality of emitters of excitation light.

14. The illumination system of claim 1, wherein the illumination system has the ability to modulate the beam of white light.

15. The illumination system of claim 1, wherein the illumination system has the ability to modulate the light output in synchronization with a camera shutter.

16. An illumination system comprising:

a first light source comprising a plurality of emitters of blue excitation light and a luminescent material positioned to receive the blue excitation light from the plurality of emitters of blue excitation light and emit light of a first color having a longer wavelength than the blue excitation light whereby the first light source outputs a first light beam of said first color;

a second light source, wherein the second light source includes a Light Emitting Diode (LED), wherein the second light source emits a second light beam of a blue color different than the first color;

a third light source, wherein the third light source includes another Light Emitting Diode (LED), wherein the third light source emits a third light beam of a red color different than the first color and second color;

a plurality of reflective optical components positioned to combine the first light beam of the first color, the second light beam of the blue color, the third light beam of the red color, on a main optical axis of the illumination system to generate a beam of white light; and

an output system positioned to receive said beam of white light and configured to focus said beam of white light into a light guide.

17. The illumination system of claim 16, wherein the first light beam of said first color has a greater optical power and a greater optical power per unit area than the blue excitation light emitted by each of said plurality of emitters of blue excitation light individually.

18. The illumination system of claim 16, further comprising:

an optical concentrator configured to convert said first light emitted by said luminescent material to an area and solid angle suitable for generating the first light beam of said first color while substantially preserving etendue.

19. The illumination system of claim 18, wherein the optical concentrator is tapered such it has an output surface having an area larger than the optical output surface of the luminescent material.

20. The illumination system of claim 16, wherein said beam of white light has an optical power of at least 2000 lumens.