Led lamp

• US 20020070681A1
• Filed: 05/25/2001
• Published: 06/13/2002
• Est. Priority Date: 05/31/2000
• Status: Active Grant

• Current Assignee: Sovereign Peak Ventures, LLC (Dominion Harbor Enterprises, LLC)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Nagai, Hideo, Matsui, Nobuyuki, Tamura, Tetsushi, Shimizu, Masanori, Shimomura, Yoko
• Granted Patent: US 6,577,073 B2
• Time in Patent Office: Days
• US Class Current: 315/246
• CPC Class Codes: F21K 9/233 specially adapted for generating a spot light distribution, e.g. for substitution of reflector lamps
• CPC Class Codes: F21Y 2107/50 on planar substrates or supports, but arranged in different planes or with differing orientation, e.g. on plate-shaped supports with steps on which light-generating elements are mounted
• 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: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/8592 Applying permanent coating, e.g. protective coating
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 27/15 including semiconductor components having potential barriers, specially adapted for light emission
• CPC Class Codes: H01L 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/181 Encapsulation
• CPC Class Codes: H01L 33/50 Wavelength conversion elements
• CPC Class Codes: Y10S 362/80 Light emitting diode

Abstract

An LED lamp includes blue and red LEDs and a phosphor. The blue LED produces an emission at a wavelength falling within a blue wavelength range. The red LED produces an emission at a wavelength falling within a red wavelength range. The phosphor is photoexcited by the emission of the blue LED to exhibit a luminescence having an emission spectrum in an intermediate wavelength range between the blue and red wavelength ranges.

Claims

1. An LED lamp comprising:

a blue LED for producing an emission at a wavelength falling within a blue wavelength range;

a red LED for producing an emission at a wavelength falling within a red wavelength range; and

a phosphor, which is photoexcited by the emission of the blue LED to exhibit a luminescence having an emission spectrum in an intermediate wavelength range between the blue and red wavelength ranges.

2. The lamp of claim 1, wherein the red LED produces the emission at a peak wavelength of 600 nm or more.

3. The lamp of claim 1, wherein the blue LED produces the emission at a peak wavelength of between 450 and 470 nm, and

wherein the red LED produces the emission at a peak wavelength of between 610 and 630 nm, and

wherein the phosphor exhibits the luminescence at a peak wavelength of between 520 and 560 nm.

4. The lamp of claim 1, wherein if the LED lamp has a correlated color temperature of 5000 K or more and if color rendering performance of the lamp is appraised using a reconstituted daylight source as a standard source, the blue LED produces the emission at a peak wavelength of between 450 and 460 nm, the red LED produces the emission at a peak wavelength of 600 nm or more and the phosphor exhibits the luminescence at a peak wavelength of between 520 and 560 nm.

5. The lamp of claim 1, wherein if the LED lamp has a correlated color temperature of less than 5000 K and if color rendering performance of the lamp is appraised using a black-body source as a standard source, the red LED produces the emission at a peak wavelength of between 615 and 650 nm and the phosphor exhibits the luminescence at a peak wavelength of between 545 and 560 nm.

6. The lamp of claim 1, further comprising means for controlling an intensity of the emission produced by the red LED.

7. The lamp of claim 6, wherein the control means is a variable resistor.

8. The lamp of claim 6, wherein the blue LED produces the emission at a peak wavelength of between 455 and 465 nm, and

wherein the red LED produces the emission at a peak wavelength of between 620 and 630 nm, and

wherein the phosphor exhibits the luminescence at a peak wavelength of between 540 and 550 nm.

9. The lamp of claim 1, wherein the phosphor is a yellow emitting phosphor that exhibits a yellow luminescence when photoexcited by the emission of the blue LED.

10. The lamp of claim 9, wherein the yellow emitting phosphor is either a YAG phosphor or a phosphor doped with Mn as a luminescence center.

11. The lamp of claim 1, wherein the phosphor is a green emitting phosphor that exhibits a green luminescence when photoexcited by the emission of the blue LED.

12. The lamp of claim 11, wherein the green emitting phosphor is either a YAG phosphor or a phosphor doped with at least one element selected from the group consisting of Tb, Ce, Eu and Mn as a luminescence center.

13. The lamp of claim 1, wherein the blue and red LEDs and the phosphor are integrated together within a single envelope.

14. The lamp of claim 13, wherein a site at which the blue LED produces the emission thereof and a site at which the red LED produces the emission thereof are both located in a single chip.

15. The lamp of claim 1, wherein an LED light source, which includes the blue LED and the phosphor, and another LED light source, including the red LED, are separately disposed to make a cluster.

16. A lamp unit comprising:

at least one LED lamp as recited in claim 1;

and a power supply for supplying power to the lamp.

17. The unit of claim 16, further comprising a reflector for reflecting light produced from the lamp(s).