Light source with non-white and phosphor-based white LED devices, and LCD assembly

• US RE41,685 E1
• Filed: 04/19/2007
• Issued: 09/14/2010
• Est. Priority Date: 12/28/1999
• Status: Expired due to Term

• Current Assignee: Technical LED Intellectual Property, LLC (Fred DuFresne)
• Original Assignee: Honeywell International Inc.
• Inventors: Feldman, Alan Stuart, Davey, Dennis Michael, Cull, Brian David
• Primary Examiner(s): Negron, Ismael
• Application Number:
  US11/788,399
• Time in Patent Office: 1,244 Days
• Field of Search: 362/97, 362/228, 362/230, 362/231, 362/237, 362/249, 362/800, 362/240, 362/236, 362/249.02, 362/97.3, 349/69, 349/70
• US Class Current: 362/237
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133604 with lamps
• CPC Class Codes: G02F 1/133608 including particular frames or supporting means
• CPC Class Codes: H01L 25/13 the devices being of a type provided for in group H01L33/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 2924/09701 Low temperature co-fired ceramic [LTCC]
• CPC Class Codes: H01L 33/486 adapted for surface mounting
• CPC Class Codes: H01L 33/60 Reflective elements

Abstract

A light source incorporates phosphor-based white light emitting diodes (LEDs). The LEDs may be raised off the floor of the optical cavity to permit light to be emitted from the base of the LED. Additionally, a reflective protrusion may be placed beneath the raised LED to aid in redirecting light forward. The LEDs may be skewed in relation to adjacent LEDs to reduce interference. Non-white LEDs may be incorporated into the light source to permit for selective color tuning. Fluorescent lamps may also be implemented in combination with the LEDs to form a hybrid light source. The light source may be used as a backlight for a liquid crystal display assembly.

Claims

1. A light source, comprising:

an optical cavity having a floor;

at least one light emitting diode (LED) having a top and a bottom coupled to said floor such that said bottom of said at least one light emitting diode is elevated above said floor of said optical cavity; and

a reflective protrusion located below said at least one LED.

2. A light source comprising:

an optical cavity having a floor;

at least one fluorescent lamp coupled to said optical cavity; and

at least two LEDs coupled to said optical cavity, wherein adjacent said at least two LEDs are skewed at approximately 45°

relative to one another.

3. A light source comprising:

an optical cavity having a floor;

at least one fluorescent lamp coupled to said optical cavity; and

at least two LEDs coupled to said optical cavity, wherein adjacent said at least two LEDs are perpendicular to one another.

4. A light source comprising:

an optical cavity having a floor;

at least one fluorescent lamp coupled to said optical cavity; and

at least one LED coupled to said optical cavity, wherein said at least one LED is coupled with said optical cavity such that said LED is elevated from said floor of said optical cavity.

5. A light source according to claim 4 further comprising a protrusion on said floor positioned beneath said elevated LED.

6. A light source comprising:

an optical cavity having a floor;

at least two fluorescent lamps coupled to said optical cavity; and

at least one LED coupled to said optical cavity, wherein two of said fluorescent lamps are located at opposing sides of said optical cavity, and said LEDs are located at intervals around substantially the perimeter of said optical cavity.

7. A method of manufacturing a light source comprising the steps of:

providing an optical cavity having a floor;

mounting at least one LED having a top and bottom in said optical cavity such that said bottom of said LED is elevated above said floor of said optical cavity; and

providing a protrusion below said at least at one LED.

8. A method of manufacturing a light source comprising the steps of:

providing an optical cavity having a floor;

mounting at least one LED having a top and bottom in said optical cavity such that said bottom of said LED is elevated above said floor of said optical cavity; and

mounting at least one fluorescent lamp in said optical cavity.

9. A light source comprising:

an optical cavity having a floor;

a plurality of fluorescent lamps coupled to said optical cavity substantially parallel to one other; and

a plurality of LEDs coupled to said optical cavity interspersed among said fluorescent lamps, wherein said plurality of LEDs are coupled to said optical cavity, said plurality of LEDs having tops and bottoms and being coupled to said optical cavity such that said bottoms of said LEDs are elevated above said floor.

10. A light source comprising:

an optical cavity;

a plurality of first light-emitting diodes each of which is a phosphor light-emitting diode that emits white light, each first light-emitting diode comprising a diode encased in a light-transmitting package;

a plurality of second light-emitting diodes each of which emits non-white light, each second light-emitting diode comprising a diode encased in a light-transmitting package;

wherein the first and second light-emitting diodes are arranged to emit light into the optical cavity such that mixing of spectral outputs from the first and second light-emitting diodes occurs in the optical cavity.

11. A light source of claim 10, further comprising at least one third light-emitting diode having a spectral output different from those of the first and second light-emitting diodes.

12. A light source of claim 11, wherein the spectral output of the second light-emitting diodes is a red output.

13. A light source of claim 11, wherein the spectral output of the third light-emitting diode is a green output.

14. A light source of claim 13, further comprising at least one fourth light-emitting diode having a blue output.

15. A liquid crystal display assembly comprising:

a backlight including;

an optical cavity;

a plurality of first light-emitting diodes each of which is a phosphor light-emitting diode that emits white light, each first light-emitting diode comprising a diode encased in a light-transmitting package;

a plurality of second light-emitting diodes each of which emits non-white light, each second light-emitting diode comprising a diode encased in a light-transmitting package;

wherein spectral outputs of the first and second light-emitting diodes are operative to tune a color balance of the backlight;

wherein the first and second light-emitting diodes are arranged to emit light into the optical cavity such that mixing of the spectral outputs from the first and second light-emitting diodes occurs in the optical cavity; and

a liquid crystal display panel positioned adjacent to the backlight so as to be illuminated by the backlight.

16. A liquid crystal display assembly of claim 15, further comprising at least one filter that is configured to be used with the liquid crystal display panel and the backlight.