Light emission device

• US 8,513,873 B2
• Filed: 10/17/2011
• Issued: 08/20/2013
• Est. Priority Date: 01/10/2005
• Status: Active Grant

• Current Assignee: Creeled Incorporated
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Brandes, George R.
• Primary Examiner(s): Guharay, Karabi
• Application Number:
  US13/274,821
• Publication Number:
  US 20120032208A1
• Time in Patent Office: 673 Days
• Field of Search: 313501-503, 257 88- 89, 257 98-100
• US Class Current: 313/501
• CPC Class Codes: C09K 11/586 with alkaline earth metals
• CPC Class Codes: C09K 11/623 with zinc or cadmium
• CPC Class Codes: C09K 11/7421 with alkaline earth metals
• CPC Class Codes: C09K 11/7702 with zinc or cadmium
• CPC Class Codes: C09K 11/77342 Silicates
• CPC Class Codes: F21K 9/00 Light sources using semiconductor devices as light-generating elements, e.g. using light-emitting diodes [LED] or lasers
• CPC Class Codes: F21Y 2113/17 forming a single encapsulated light source
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• 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: Y02B 20/00 Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
• CPC Class Codes: Y10S 362/80 Light emitting diode

Abstract

A light emission device includes multiple electrically activated solid state emitters (e.g., LEDs) having differing spectral output from one another; and/or phosphor material including one or more phosphors arranged to receive spectral output from at least one of the solid state emitters and to responsively emit a phosphor output, to provide spectral output. In one arrangement, multiple LEDs and multiple phosphors have different peak wavelengths and provide aggregated light output with less than four light emission peaks. In one arrangement, a plot of aggregated output emissions (light intensity versus wavelength) has a non-negative slope between more than two wavelength peaks. In one arrangement, a light emission device generates a user-perceptible transition in color of light at a predetermined time period as an indicative of a need to perform at least one selected task.

Claims

1. A light emission device, comprising:

a first LED die adapted to emit light comprising a first peak wavelength and a second LED die adapted to emit light comprising a second peak wavelength; and

a first phosphor material adapted to emit light comprising a third peak wavelength and a second phosphor material adapted to emit light comprising a fourth peak wavelength;

wherein the first phosphor material is arranged to receive light from at least one of the first LED die and the second LED die and responsively emit first phosphor material light emissions;

wherein the second phosphor material is arranged to receive light from at least one of the first LED die and the second LED die and responsively emit second phosphor material light emissions;

wherein each of the first, second, third, and fourth peak wavelength is in the visible range and differs from the other; and

wherein aggregated light output of the light emission device has less than four light emission peaks.

2. A light emission device according to claim 1, wherein said less than four light emission peaks consists of three light emission peaks in the visible range.

3. A light emission device according to claim 1, comprising at least one of a third LED die and a third phosphor material, wherein the at least one of the third LED and the third phosphor material is adapted to emit light comprising a fifth peak wavelength that differs from each of the first and the second peak wavelength.

4. A light emission device according to claim 1, wherein at least one of the first phosphor material and the second phosphor material is arranged to receive light from each of the first LED die and the second LED die.

5. A light emission device according to claim 1, wherein the first and second LED dies and the first and second phosphor materials are disposed in a single bulb or package.

6. A light emission device according to claim 1, wherein the first and second LED dies are arranged in or on a single reflector.

7. A light emission device according to claim 1, wherein one of said less than four light emission peaks comprises a shoulder.

8. A light emission device, comprising:

a plurality of LED dies including a first LED die adapted to emit light comprising a first LED peak wavelength and a second LED die adapted to emit light comprising a second LED peak wavelength, wherein each of the first LED peak wavelength and the second LED peak wavelength is in the visible range and differs from the other; and

at least one phosphor material adapted to emit light comprising at least one phosphor material peak wavelength in the visible range that differs from the first LED peak wavelength and the second LED peak wavelength, wherein the at least one phosphor material is arranged to receive light from at least one LED die of the plurality of LED dies and responsively emit light;

wherein the first LED peak wavelength comprises a lowest wavelength peak among the following items (a) to (c);

(a) the first LED peak wavelength, (b) the second LED peak wavelength, and (c) the at least one phosphor material peak wavelength;

wherein either the second LED peak wavelength or the at least one peak phosphor wavelength comprises a highest wavelength peak among the following items (a) to (c);

(a) the first LED peak wavelength, (b) the second LED peak wavelength, and (c) the at least one phosphor material peak wavelength; and

wherein a plot of aggregated output emissions of the light emission device represented as light intensity as a function of wavelength comprises a non-negative slope at all points extending from the lowest wavelength peak to the highest wavelength peak.

9. A light emission device according to claim 8, wherein the plurality of LED dies includes a third LED die adapted to emit light comprising a third LED peak wavelength that differs from each of the first and the second LED peak wavelength.

10. A light emission device according to claim 8, wherein the at least one phosphor material comprises multiple phosphor materials including a first phosphor material adapted to emit light comprising a first phosphor material peak wavelength and a second phosphor material adapted to emit light comprising a second phosphor material peak wavelength, wherein each of the first phosphor material peak wavelength and the second phosphor material peak wavelength differs from the other.

11. A light emission device according to claim 8, wherein the second LED peak wavelength comprises a highest wavelength peak among the following items (a) to (c):

(a) the first LED peak wavelength, (b) the second LED peak wavelength, and (c) the at least one phosphor material peak wavelength.

12. A light emission device according to claim 8, wherein the at least one phosphor material comprises a highest wavelength peak among the following items (a) to (c):

(a) the first LED peak wavelength, (b) the second LED peak wavelength, and (c) the at least one phosphor material peak wavelength.

13. A light emission device according to claim 8, wherein the at least one phosphor material is arranged to receive light from each of the first LED die and the second LED die.

14. A light emission device according to claim 8, wherein the plurality of LED dies and the at least one phosphor material are disposed in a single bulb or package.

15. A light emission device according to claim 8, wherein the plurality of LED dies is arranged in or on a single reflector.