Multicolored light source

• US 20080007172A1
• Filed: 07/05/2006
• Published: 01/10/2008
• Est. Priority Date: 07/05/2006
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Inventors: Tan, Kheng Leng, Chua, Janet Bee Yin, Loo, Wei Liam
• Granted Patent: US 7,880,381 B2
• Time in Patent Office: Days
• US Class Current: 313/512
• CPC Class Codes: C09K 11/584 with zinc or cadmium
• CPC Class Codes: C09K 11/665 with alkali or alkaline earth metals
• CPC Class Codes: C09K 11/7718 with alkaline earth metals
• CPC Class Codes: C09K 11/7731 with alkaline earth metals
• CPC Class Codes: H01L 33/504 Elements with two or more wavelength conversion materials

Abstract

A plurality of different frequency absorbing materials are placed between an LED and a surface so as to generate a non-monochromatic colors. In one embodiment, a light device is arranged with light sources, each of which emit light of a different color, and by surrounding the different colored light sources with a color changing media, each of which absorb light of different colors and by allowing the light sources to be individually calibrated as to power level, a variety of colors can be achieved.

Claims

1. A light emitting diode comprising:

a housing;

at least one LED chip contained within said housing, said chip emitting light in a selected frequency; and

an encapsulant surrounding said chip, said encapsulant having light frequency absorbing characteristics spread across multiple light frequencies.

2. The light emitting diode of claim 1 wherein said encapsulant contains a plurality of different phosphors, some of said phosphors having light absorbing characteristics in a first range of light frequencies and some of said phosphors having light absorbing characteristics in a second range of light frequencies.

3. The light emitting diode of claim 2 wherein the color of the light output of said diode is selectively controlled by changing the loading factor of said phosphors to obtain a particular desired color.

4. The light emitting diode of claim 2 further comprising:

a plurality of LED chips, each chip emitting light in a different frequency.

5. A light source comprising:

at least two LED chips, each chip operable for emitting light of a different frequency; and

encapsulant material surrounding said chips, said encapsulant material designed to absorb and emit a plurality of frequencies of light as emitted from said chips.

6. The light source of claim 5 wherein said encapsulate material comprises:

at least two different phosphors each having selected absorption characteristics matched to the color of the desired output light of said light source.

7. The light source of claim 6 wherein the loading factor for each phosphor is different.

8. The light source of claim 6 further comprising:

means for adjusting the output power of selected ones of said LED chips.

9. The light source of claim 8 wherein said adjusting means is enabled based upon a reading of the actual output frequency of the light.

10. A light device comprising:

a plurality of light sources, each source emitting a different color light;

means for absorbing certain frequencies so as to change the light from a first color to a converted color; and

means for actively selecting one or more of said light sources to produce a desired output color selected from within the chromaticity diagram.

11. The light device of claim 10 wherein said absorbing means comprises a plurality of different frequency absorbing materials.

12. The light device of claim 10 wherein said selected colors are non-monochromatic colors other than white.

13. The light device of claim 12 further comprising:

means for adjusting the input voltage to selected ones of said light sources so as to achieve said desired non-monochromatic color output.

14. The light source of claim 13 wherein said absorbing means is at least two different materials selected from the list of compounds comprising:

CaS;

Eu2+, Mn2+;

SrS;

Eu2+;

(Zn,Cd)S;

Ag;

Mg4GeO5.5F;

Mn4+;

CaS;

Ce3+;

ZnS;

Cu+;

SrGa2S4;

Eu2+; and

YAG;

Ce3+.

15. A method of constructing an LED, said method comprising:

determining at least one desired output color, said color having at least one frequency not directly emitted from an LED;

selecting at least one LED chip having an emitted color other than said selected color; and

placing a plurality of different frequency light absorption materials between said LED chip and a top surface of said LED.

16. The method of claim 15 further comprising:

adding a plurality of LEDs constructed using said determining, said selecting and said placing on a substrate under a single cover to form a single display device.

17. The method of claim 16 further comprising:

adding a controller and a sensor to said display device so as to control the color output of said display device.

18. The method of claim 17 wherein said frequency absorbing materials are selected from the list of:

CaS;

Eu2+, Mn2+;

SrS;

Eu2+;

(Zn,Cd)S;

Ag;

Mg4GeO5.5F;

Mn4+;

CaS;

Ce3+;

ZnS;

Cu+;

SrGa2S4;

Eu2+; and

YAG;

Ce3+.

19. The method of claim 17 wherein said desired output color is non-monochromatic and non white.

20. The method of claim 19 wherein said placing comprises selection of loading factors for each absorbing material.