Light-emitting diode white light source

• US 5,851,063 A
• Filed: 10/28/1996
• Issued: 12/22/1998
• Est. Priority Date: 10/28/1996
• Status: Expired due to Term

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Liu, Yung Sheng, Duggal, Anil Raj, Doughty, Douglas Allen
• Primary Examiner(s): Dority, Carroll B.
• Application Number:
  US08/736,843
• Time in Patent Office: 785 Days
• Field of Search: 362/800, 362/231
• US Class Current: 362/231
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: Y10S 362/80 Light emitting diode

Abstract

A system of at least three multi-colored LED'"'"'s has an optimized color rendering index by proper selection of the wavelengths of each LED, such system being useful for general illumination purposes.

Claims

1. A general illumination system, comprising:

at least three light-emitting diodes, each light-emitting diode providing visible light at a preselected wavelength for optimizing color rendition index for the system for general illumination applications, each preselected wavelength being defined by a predetermined chromaticity and a maximized color rendition index at the predetermined chromaticity, the predetermined chromaticity being proximate the locus of points in chromaticity space corresponding to blackbody sources.

2. The system of claim 1, comprising three light-emitting diodes, the wavelength for each light-emitting diode being selected such that the color rendition index for the system is at least approximately 80.

3. The system of claim 2 wherein the selected wavelength for a first of the three light-emitting diodes is in a range from approximately 530 to approximately 570 nm, the selected wavelength for a second of the three light-emitting diodes is in a range from approximately 455 to approximately 490 nm, and the selected wavelength for a third of the three light-emitting diodes is in a range from approximately 605 to approximately 630 nm.

4. The system of claim 1, comprising at least four light-emitting diodes, the wavelength for each light-emitting diode being selected such that the color rendition index for the system is at least approximately 85.

5. The system of claim 4 wherein the selected wavelength for a first of the light-emitting diodes is in a range from approximately 440 to approximately 450 nm, the selected wavelength for a second of the light-emitting diodes is in a range from approximately 455 to approximately 505 nm, the selected wavelength for a third of the light-emitting diodes is in a range from approximately 555 to approximately 565 nm, and the selected wavelength for a fourth of the light-emitting diodes is in a range from approximately 610 to approximately 620 nm.

6. A method for providing white light for a general illumination system, comprising:

specifying a predetermined chromaticity such that the predetermined chromaticity is proximate the locus of points in chromaticity space corresponding to blackbody sources; and

selecting wavelengths for at least three light-emitting diodes for providing visible light having a maximized color rendition index at the predetermined chromaticity.

7. The method of claim 6 wherein the step of selecting comprises maximizing color rendition index using wavelength versus color temperature data.

8. The method of claim 6 wherein the step of selecting comprises selecting wavelengths for three light-emitting diodes such that the color rendition index for the system is at least approximately 80.

9. The method of claim 8 wherein the selected wavelength for a first of the three light-emitting diodes is in a range from approximately 530 to approximately 570 nm, the selected wavelength for a second of the three light-emitting diodes is in a range from approximately 455 to approximately 490 nm, and the selected wavelength for a third of the three light-emitting diodes is in a range from approximately 605 to approximately 630 nm.

10. The method of claim 6 wherein the step of selecting comprises selecting wavelengths for four light-emitting diodes such that the color rendition index for the system is at least approximately 80.

11. The method of claim 10 wherein the selected wavelength for a first of the light-emitting diodes is in a range from approximately 440 to approximately 450 nm, the selected wavelength for a second of the light-emitting diodes is in a range from approximately 455 to approximately 505 nm, the selected wavelength for a third of the light-emitting diodes is in a range from approximately 555 to approximately 565 nm, and the selected wavelength for a fourth of the light-emitting diodes is in a range from approximately 610 to approximately 620 nm.