Light emitting diode illumination system

• US 8,279,442 B2
• Filed: 01/24/2011
• Issued: 10/02/2012
• Est. Priority Date: 08/06/2007
• Status: Active Grant

• Current Assignee: Lumencor, Inc.
• Original Assignee: Lumencor, Inc.
• Inventors: Brukilacchio, Thomas J., Conner, Arlie R.
• Primary Examiner(s): Ton, Tri T
• Application Number:
  US13/012,658
• Publication Number:
  US 20110116261A1
• Time in Patent Office: 617 Days
• Field of Search: 362227-228, 362216-225, 36221701-21717, 362253-254, 362/260, 362307-310, 362/257, 362/296.01, 362/317, 362326-329, 362 23- 30, 356402-420, 356/432, 356 43- 50
• US Class Current: 356/417
• 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 is 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. In various embodiments of the invention, a plurality of independent narrow band colors can be coaxially combined.

Claims

1. A fiber optic illumination system, comprising:

a first LED light source, wherein the first LED light source emits a first light of a first color wherein the first color is a color other than green; and

a luminescent rod light source, wherein the luminescent rod light source includes

a second LED light source comprising a linear array of LEDs, wherein the second LED light source emits blue light, and

a luminescent rod having a straight longitudinal surface parallel to said linear array of LEDs such that the luminescent rod is positioned to receive the blue light, wherein the blue light is absorbed by the luminescent rod which then generates by luminescence and emits green light;

the luminescent rod having an outlet aperture wherein the green light exits the luminescent rod at the outlet aperture;

a liquid light guide adapted to couple the fiber optic illumination system to a fiber optic device; and

associated optics that combines the first light of the first light source with the green light generated by the luminescent rod into a combined light beam on a same optical axis and focuses said combined light beam into said liquid light guide.

2. The fiber optic illumination system of claim 1, further comprising a third LED light source that emits red light;

and

wherein the associated optics combines the red light of the third light source with the first light of the first light source and the green light generated by the luminescent rod into a combined light beam on the same optical axis.

3. The fiber optic illumination system of claim 1, further comprising a light pipe to couple the combined light beam to a system that uses one or both the first light and the green light of the illumination system.

4. The fiber optic illumination system of claim 1, further comprising a reflective element positioned at one end of the luminescent rod to reflect green light towards the outlet aperture.

5. The fiber optic illumination system of claim 1, wherein the first LED light source includes a plurality of LEDs, and the second LED light source includes a plurality of LEDs.

6. The fiber optic illumination system of claim 1, wherein the associated optics includes a combination of collimator and dichroic mirrors.

7. The fiber optic illumination system of claim 1, wherein the luminescent rod is out-coupled through a dome or similar shaped structure made of a material having a substantially similar index of refraction as the luminescent rod.

8. The fiber optic illumination system of claim 1, wherein the second LED light source comprises a plurality of linear arrays of LEDs, the plurality of linear arrays positioned parallel to the luminescent rod with the LEDS no greater than 200 microns from the rod.

9. The fiber optic illumination system of claim 1, wherein the luminescent rod comprises one of a single crystal Ce:

YAG rod and a sintered ceramic Ce;

YAG rod.

10. The fiber optic illumination system of claim 1, further comprising:

a third LED light source that emits red light,

wherein the first light emitted by the first LED light source is blue light; and

wherein the associated optics combines the red light of the third light source with the blue light of the first light source and the green light generated by the luminescent rod into a combined light beam on the same optical axis.

19. The fiber optic illumination system of claim 1, further comprising:

a laser light source which emits coherent light; and

wherein the associated optics combines the coherent light of the laser light source with the first light of the first light source and the green light generated by the luminescent rod into a combined light beam on the same optical axis and focuses said combined light beam into said liquid light guide.

20. The fiber optic illumination system of claim 1 further comprising:

a third LED light source which emits red light, and

a laser light source which emits coherent light;

wherein the first light emitted by the first LED light source is blue light; and

wherein the associated optics combines the red light of the third light source with the blue light of the first light source and the green light generated by the luminescent rod and the coherent light emitted by the laser light source into a combined light beam on the same optical axis and focuses said combined light beam into said liquid light guide.

11. A method of generating illumination using a fiber optic illumination system, comprising the steps of:

applying a first potential to a first light source, wherein the first light source is selected from one of a first Light Emitting Diode (LED) and a laser, wherein the first light source emits a first light of a first color, wherein the first color is a color other than green;

applying a second potential to a second light source comprising a linear array of LEDs to generate second light in a second color, wherein the second color is a color other than green, which second light is directed at a luminescent rod having a straight longitudinal surface parallel to said linear array of LEDs such that the luminescent rod is excited along a length of the luminescent rod such that the second light is absorbed by the luminescent rod which then generates by luminescence and emits green light through an outlet aperture of the luminescent rod; and

combining the first light and the green light into a combined beam on an optical axis and focusing said combined beam into a liquid light guide adapted to couple the combined beam into a fiber optic device.

12. The method of claim 11 further comprising:

applying a third potential to a third light source, wherein the third light source is selected from one of a Light Emitting Diode (LED) and a laser, wherein the third light source emits a third light of a third color different than the first color, wherein the third color is a color other than green; and

wherein said combining step includes combining said first light, said green light, and said third light into a combined beam on an optical axis and focusing said combined beam into a liquid light guide adapted to couple the combined beam into a fiber optic device.

13. The method of claim 12, wherein said combined beam comprises white light.

14. The method of claim 12, further comprising:

applying a fourth potential to a fourth light source, wherein the fourth light source is a Light Emitting Diode (LED), wherein the fourth light source emits a fourth light of a fourth color different than the first color and the third color, wherein the fourth color is a color other than green; and

wherein said combining step includes combining said first light, said green light, said third light, and said fourth light into a combined beam on an optical axis and focusing said combined beam into a liquid light guide adapted to couple the combined beam into a fiber optic device.

15. The method of claim 11, wherein said first light source includes a plurality of LED light sources that emit the first light of the first color.

16. The method of claim 11, wherein said combining step includes combining the first light and the green light into a combined beam on an optical axis using a combination of one or more collimators and dichroic mirrors and focusing said combined beam into a liquid light guide adapted to couple the combined beam into a fiber optic device.

17. The method of claim 11, further comprising cooling said luminescent rod by forcing air along said luminescent rod.

18. The method of claim 11, further comprising cooling said luminescent rod.

21. An illuminator, comprising:

a first LED light source which emits a first light of a first color;

a luminescent rod light source, wherein the luminescent rod light source includes,

a linear array of blue LEDs which emits blue light,

a luminescent rod having a straight longitudinal surface parallel to said linear array of blue LEDs such that the luminescent rod receives the blue light from the linear array of blue LEDs, the luminescent rod made from a material which absorbs the blue light and generates green light by luminescence, wherein the green light is emitted through an outlet aperture of the luminescent rod;

one or more lenses and mirrors that combine the first light and the green light into a combined light beam and focus said combined light beam into a liquid light guide.

22. The illuminator of claim 21 further comprising:

a second LED light source which emits second light of a second color different than the first color;

a third LED light source which emits third light of a third color different than the first color and second color; and

wherein the one or more lenses and mirrors combine the first light, the second light, the third light, and the green light into a combined light beam and focus said combined light beam into the liquid light guide.

23. The illuminator of claim 22, further comprising:

a fourth LED light source which emits a fourth light of a fourth color different than the first color, the second color, and the third color; and

wherein the one or more lenses and mirrors combine the first light, the second light, the third light, the fourth light, and the green light into a combined light beam and focus said combined light beam into the liquid light guide.

24. The illuminator of claim 22, further comprising:

a laser light source which emits a coherent light; and

wherein the one or more lenses and mirrors combine the first light, the second light, the third light, the coherent light, and the green light into a combined light beam and focus said combined light beam into the liquid light guide.

25. The illuminator of claim 22, wherein the combined light beam comprises white light.

26. The illuminator of claim 22, further comprising a high pressure fan adapted to cool the luminescent rod by directing air between the linear array of blue LEDs and the straight longitudinal surface of the luminescent rod.

27. The illuminator of claim 22, wherein the luminescent rod light source comprises a plurality of linear arrays of LEDs, the plurality of linear arrays positioned parallel to the luminescent rod with the LEDs no greater than 200 microns from the luminescent rod.

28. The illuminator of claim 22, wherein the luminescent rod comprises one of a single crystal Ce:

YAG rod and a sintered ceramic Ce;

YAG rod.

29. The illuminator of claim 22, wherein the first color is red.

30. The illuminator of claim 22, wherein liquid light guide is adapted to couple the illuminator to one of a microscope and an endoscope.

31. The illuminator of claim 22, further comprising a reflective element positioned at one end of the luminescent rod to reflect green light towards the outlet aperture.