Wavelength converter and light-emitting device having same
AssigneeOsram Sylvania Inc.
InventorsJohn F. Kelso, Kathleen A. Lawson
Life of this patent
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Abstract
An alumina-based ceramic wavelength converter is described having a surface layer containing a second phase of alumina, preferably as alumina crystallites. The surface layer is formed as a result of the sintering process used to form the bulk ceramic which is itself substantially transparent. The ceramic wavelength converter is combined with a light emitting diode to form a light emitting device. Preferably, the ceramic wavelength converter is comprised of an alumina-based phosphor represented by a general formula A3B5O12:Ce, wherein A is Y, Sc, La, Gd, Lu, or Tb and B is Al, Ga or Sc.
Claims22
A wavelength converter comprising a solid monolithic piece of a luminescent ceramic material, the ceramic material comprising an alumina-based phosphor capable of converting primary light having a first peak wavelength into secondary light having a second peak wavelength, a bulk portion of the converter being substantially transparent, and the converter having at least one major surface with an as-sintered surface layer having an alumina second phase.
A light-emitting device, comprising:
- a light-emitting diode that emits a primary light having a first peak wavelength and a wavelength converter positioned to receive the primary light from the light-emitting diode, the wavelength converter comprising a solid monolithic piece of a luminescent ceramic material, the ceramic material comprising an alumina-based phosphor capable of converting at least a portion of the primary light into secondary light having a second peak wavelength, a bulk portion of the converter being substantially transparent, and the converter having at least one major surface with an as-sintered surface layer having an alumina second phase.
Dependencies are inferred from the claim text.