Illumination source with liquid cooled plate

• US 8,267,528 B2
• Filed: 09/01/2011
• Issued: 09/18/2012
• Est. Priority Date: 05/19/2005
• Status: Expired due to Fees

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Conner, Arlie R., Donnelly, Sean M., Oehler, Peter R.
• Primary Examiner(s): Epps, Georgia Y
• Assistant Examiner(s): Cruz, Magda
• Application Number:
  US13/223,879
• Publication Number:
  US 20120025220A1
• Time in Patent Office: 383 Days
• Field of Search: 353/94, 353/54, 362/555, 362/551, 385/133
• US Class Current: 353/94
• CPC Class Codes: G02B 27/283 used for beam splitting or combining
• CPC Class Codes: G03B 21/16 Cooling; Preventing overheating
• CPC Class Codes: G03B 21/2033 LED or laser light sources
• CPC Class Codes: G03B 21/204 using secondary light emission, e.g. luminescence or fluorescence using different colours G03B33/00; if related to video signals H04N9/3197
• CPC Class Codes: G03B 21/2073 Polarisers in the lamp house peculiar to electronic spatial light modulators H04N9/3197
• CPC Class Codes: H04N 9/3141 Constructional details thereof details not peculiar to the presence of an electronic spatial light modulator G03B21/14

Abstract

An illumination source includes a number of light emitting diodes (LEDs) operating at a first wavelength. Light from the LEDs illuminates a phosphor material that generates light at a second wavelength. A reflective polarizer transmits light at the second wavelength in a first polarization state and reflects light at the second wavelength in a second polarization state orthogonal to the first polarization state. The light at the second wavelength reflected by the reflective polarizer is directed back towards the phosphor material without an increase in angular range. In some embodiments the LEDs, having a conformal layer of phosphor material, are attached directly to the first surface of a liquid cooled plate. A liquid coolant contacts a second surface of the plate.

Claims

1. An illumination source, comprising:

an array of one or more light emitting diodes (LEDS);

a liquid cooled plate having a first surface and a second surface, the LEDS being attached directly to the first surface of the liquid cooled plate, a liquid coolant contacting the second surface of the liquid cooled plate; and

a phosphor material disposed on the one or more LEDs,

wherein at least one of the LEDs is bonded to the liquid cooled plate by eutectic bonding or by a conductive epoxy.

2. A source as recited in claim 1, wherein the phosphor material comprises SrGa₂S₄.

3. A source as recited in claim 1, further comprising a first light collecting/focusing unit that accepts light from the array of one or more LEDs and forms at least some of the light into a telecentric beam.

4. A source as recited in claim 3, wherein the light collecting/focusing unit comprises a tapered light pipe.

5. A source as recited in claim 1, wherein the LEDs comprise silicon carbide.

6. A source as recited in claim 1, wherein at least one of the LEDs is bonded to the liquid cooled plate by eutectic bonding.

7. An illumination source, comprising:

an array of one or more light emitting diodes (LEDS);

a liquid cooled plate having a first surface and a second surface, the LEDS being attached directly to the first surface of the liquid cooled plate, a liquid coolant contacting the second surface of the liquid cooled plate; and

a phosphor material disposed on the one or more LEDs,

wherein at least one of the LEDs is conformally coated with the phosphor material.

8. A source as recited in claim 7, wherein the phosphor material comprises SrGa₂S₄.

9. A source as recited in claim 7, further comprising a first light collecting/focusing unit that accepts light from the array of one or more LEDS and forms at least some of the light into a telecentric beam.

10. A source as recited in claim 9, wherein the light collecting/focusing unit comprises a tapered light pipe.

11. A source as recited in claim 7, wherein the LEDs comprise silicon carbide.

12. A source as recited in claim 7, wherein at least one of the LEDs is bonded to the liquid cooled plate by eutectic bonding or by a conductive epoxy.

13. A source as recited in claim 12, wherein at least one of the LEDs is bonded to the liquid cooled plate by eutectic bonding.

14. An illumination source, comprising:

an array of one or more light emitting diodes (LEDS);

a liquid cooled plate having a first surface and a second surface, the LEDS being attached directly to the first surface of the liquid cooled plate, a liquid coolant contacting the second surface of the liquid cooled plate; and

a phosphor material disposed on the one or more LEDs,

wherein the liquid cooled plate is a microchannel cold plate, and

wherein at least one of the LEDs is bonded to the liquid cooled plate by eutectic bonding or by a conductive epoxy.

15. A source as recited in claim 14, wherein the phosphor material comprises SrGa₂S₄.

16. A source as recited in claim 14, further comprising a first light collecting/focusing unit that accepts light from the array of one or more LEDS and forms at least some of the light into a telecentric beam.

17. A source as recited in claim 16, wherein the light collecting/focusing unit comprises a tapered light pipe.

18. A source as recited in claim 14, wherein the LEDs comprise silicon carbide.

19. A source as recited in claim 14, wherein at least one of the LEDs is bonded to the liquid cooled plate by eutectic bonding.