Polarized, LED-based illumination source
First Claim
1. An illumination source, comprising:
- an array of one or more light emitting diodes (LEDs) capable of emitting light at a first wavelength;
a first light collecting/focusing unit to form at least some of the light at the first wavelength into a telecentric beam;
a phosphor capable of generating light at a second wavelength when illuminated by light at the first wavelength, the telecentric beam being directed to the phosphor;
a reflective polarizer disposed to transmit light at the second wavelength, received from the phosphor, in a first polarization state and to reflect light at the second wavelength in a second polarization state back to the phosphor; and
a polarization control element disposed between the phosphor and the reflective polarizer.
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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.
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Citations
21 Claims
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1. An illumination source, comprising:
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an array of one or more light emitting diodes (LEDs) capable of emitting light at a first wavelength; a first light collecting/focusing unit to form at least some of the light at the first wavelength into a telecentric beam; a phosphor capable of generating light at a second wavelength when illuminated by light at the first wavelength, the telecentric beam being directed to the phosphor; a reflective polarizer disposed to transmit light at the second wavelength, received from the phosphor, in a first polarization state and to reflect light at the second wavelength in a second polarization state back to the phosphor; and a polarization control element disposed between the phosphor and the reflective polarizer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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Specification