LED illumination device with layered phosphor pattern
First Claim
1. A method of forming a light emitting device comprising depositing a first phosphor material over a semiconductor light emitter and depositing a second phosphor material over said first phosphor material, wherein said first phosphor material has at least one of a shorter decay time and a lower absorption of radiation from said semiconductor light emitter than said second phosphor material.
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Abstract
A method of applying at least two phosphors to an LED, wherein a first phosphor material having a lower absorption, shorter luminescence decay time, and/or lower thermal quenching than a second phosphor material is positioned closer to the LED than the second phosphor. Such an arrangement provides a light emitting device with improved lumen output and color stability over a range of drive currents.
29 Citations
37 Claims
- 1. A method of forming a light emitting device comprising depositing a first phosphor material over a semiconductor light emitter and depositing a second phosphor material over said first phosphor material, wherein said first phosphor material has at least one of a shorter decay time and a lower absorption of radiation from said semiconductor light emitter than said second phosphor material.
- 14. A light emitting device comprising a semiconductor light emitter and at least two phosphor materials, wherein a first phosphor material is disposed closer to said light emitting diode or laser diode than a second phosphor material, said first phosphor material having at least one of a shorter decay time and a lower absorption of radiation emitted from said semiconductor light emitter than said second phosphor material.
- 29. A light emitting device comprising a light emitting diode or laser emitting diode and at least two phosphor materials, wherein a first phosphor material is positioned such that radiation emitted from said light emitting diode or laser emitting diode strikes said first phosphor material prior to striking said second phosphor material, and further wherein said first phosphor material has at least one of a shorter decay time and a lower absorption of radiation emitted from said light emitting diode or laser emitting diode than said second phosphor material.
- 31. A method of forming a light emitting device comprising depositing a first phosphor material over a semiconductor light emitter and depositing a second phosphor material over said first phosphor material, wherein said first phosphor material has reduced thermal quenching than said second phosphor material.
Specification