LIGHT SOURCE COMPRISING A LIGHT-EXCITABLE MEDIUM

• US 20080106887A1
• Filed: 10/30/2007
• Published: 05/08/2008
• Est. Priority Date: 10/31/2006
• Status: Abandoned Application

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: TIR Technology LP
• Inventors: SALSBURY, Marc, ASHDOWN, Ian
• Application Number:
  US11/928,236
• Publication Number:
  US 20080106887A1
• Time in Patent Office: Days
• US Class Current: 362/84
• 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 3/08 the material comprising photoluminescent substances
• CPC Class Codes: F21V 3/12 the coatings comprising photoluminescent substances
• CPC Class Codes: F21Y 2113/13 comprising an assembly of point-like light sources
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]

Abstract

The present invention provides a light source having an improved output optical quality. In general, the light source comprises one or more light-emitting elements in each of at least a first, a second and a third colour. The combined spectral power distribution of these light-emitting elements generally defines a spectral concavity. The light source further comprises a light-excitable medium configured and disposed to absorb a portion of the light emitted by one or more of the light-emitting elements and emit light defined by a complementary spectral power distribution having a peak located within the concavity. By combining the spectral output of the light-emitting elements with the spectral output of the light-excitable medium, an optical quality of the light source is improved.

Claims

1. A light source, comprising:

one or more light-emitting elements in each of at least a first, a second and a third colour, a combined spectral power distribution thereof defining a spectral concavity having a minimum located between about 550 nm and about 600 nm; and

a light-excitable medium configured and disposed to absorb a portion of the light emitted by one or more of said light-emitting elements and emit light defined by a complementary spectral power distribution having a peak located within said concavity;

wherein an optical quality of the light source output is improved by a combination of said complementary spectral power distribution with said combined spectral power distribution.

2. The light source as claimed in claim 1, wherein said complementary spectral power distribution is a substantially narrowband spectral power distribution.

3. The light source as claimed in claim 2, wherein a half-width of said narrowband spectral power distribution is lesser than that of one or more of said light-emitting elements.

4. The light source as claimed in claim 2, wherein a half-width of said narrowband spectral power distribution is lesser than that of said spectral concavity.

5. The light source as claimed in claim 1, wherein said complementary spectral power distribution is a substantially broadband spectral power distribution.

6. The light source as claimed in claim 5, wherein a half-width of said broadband spectral power distribution is greater than that of one or more of said light-emitting elements.

7. The light source as claimed in claim 5, wherein a half-width of said broadband spectral power distribution is greater than that of said spectral concavity.

8. The light source as claimed in claim 1, wherein said minimum is located between about 560 nm and about 590 nm.

9. The light source as claimed in claim 1, wherein said minimum is located between about 570 nm and about 585 nm.

10. The light source as claimed in claim 1, wherein said minimum is located between about 575 nm and about 580 nm.

11. The light source as claimed in claim 1, the light source comprising one or more light-emitting elements in a fourth substantially invisible colour, said light-excitable medium configured and disposed to absorb a portion of the light emitted by said one or more light-emitting elements in said fourth colour.

12. The light source as claimed in claim 11, wherein said fourth colour is selected from the group consisting of infrared, near-infrared, ultraviolet and near ultraviolet.

13. The light source as claimed in claim 1, said first, second and third colour consisting of red, green and blue respectively.

14. The light source as claimed in claim 13, the light source comprising a further light-excitable medium configured and disposed to emit green light to further improve said optical quality.

15. The light source as claimed in claim 1, said light-excitable medium being disposed on a package component of a selected one or more of said light-emitting elements, and configured to absorb a portion of the light emitted by said selected one or more of said light-emitting elements.

16. The light source as claimed in claim 1, said light-excitable medium being disposed on a light source component distinct from said light-emitting elements.

17. The light source as claimed in claim 1, said optical quality comprising one or more of a colour quality, a colour rendering index, a chromaticity and efficiency and a colour temperature of the light source.

18. The light source as claimed in claim 1, further comprising a feedback system operatively coupled to a driving mechanism of the light source for sensing said optical quality and adjusting same as required by adjusting an output of said light-emitting elements via said driving mechanism.

19. The light source as claimed in claim 1, wherein said light-excitable medium comprises a phosphorescent material.

20. A light source, comprising:

one or more light-emitting elements in each of at least a first and a second colour, a combined spectral power distribution thereof defining a spectral deficiency between about 550 nm and about 600 nm; and

one or more light-excitable media configured and disposed to absorb a portion of the light emitted by one or more of said light-emitting elements and emit light defined by a complementary spectral power distribution having a peak located between about 550 nm and about 600 nm;

wherein an optical quality of the light source output is improved by a combination of said complementary spectral power distribution with said combined spectral power distribution.

21. The light source as claimed in claim 20, wherein said first colour is defined by a peak wavelength ranging between about 600 nm and 690 nm, and wherein said second colour is defined by a peak wavelength ranging between about 430 nm and 550 nm.

22. The light source as claimed in claim 21, wherein said first colour is red and said second colour is blue.

23. The light source as claimed in claim 20, said complementary spectral power distribution having a further peak located below about 550 nm thereby further improving said optical quality.

24. The light source as claimed in claim 23, wherein said first colour is red, said second colour is blue, and said complementary spectral power distribution comprises a first peak exhibiting a colour ranging from orange to amber and a second peak exhibiting a colour ranging from green to yellow.

25. The light source as claimed in claim 24, the light source further comprising one or more light-emitting elements in a third colour ranging from about green to yellow.