LED lamp with remote phosphor coating and method of making the lamp
AssigneeOsram Sylvania Inc.
InventorsSteven C. Allen, Richard S. Speer
Life of this patent
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Abstract
A light emitting diode (LED) lamp includes a base with one or more LED chips, an internal cover over the LED chips, where the cover is a translucent ceramic whose thermal conductivity is greater than glass, where the cover has an interior surface separated from the LED chips by a gap, and where an exterior surface of the cover is coated with a phosphor. The ceramic cover preferably has a bulk thermal conductivity of at least 5 W/(m·K), such as polycrystalline alumina. The LED chips preferably are blue LEDs and the phosphor is selected so that the lamp emits white light. In the method of making the lamp, the phosphor may be applied to the exterior surface of the cover as a preformed sheet or in a coating.
Claims8
A method of making a light emitting diode (LED) lamp, comprising the steps of:
- operably mounting one or more LED chips on a base;
- covering the LED chips with an internal cover, the cover being an at least translucent ceramic whose thermal conductivity is greater than glass, an interior surface of the cover being separated from the LED chips by a gap;
- and
- coating an exterior surface of the cover with a phosphor, the phosphor converting light of a first wavelength range emitted by the LED chips to light of a different wavelength range, by coating the exterior surface of the cover with a suspension containing the phosphor and an organic binder and removing the organic binder by heating, leaving the phosphor on the exterior surface of the cover.
Dependencies are inferred from the claim text.