Controlled LED light output by selective area roughening
AssigneeLumileds LLC
InventorsMaciej Benedict, Paul S. Martin, Boris Kharas
Life of this patent
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Abstract
The surface of a light emitting device is roughened to enhance the light extraction efficiency of the surface, but the amount of roughened area is selected to achieve a desired level of light extraction efficiency. Photo-lithographic techniques may be used to create a mask that limits the roughening to select areas of the light emitting surface. Because the amount of roughened area can be precisely controlled, the light extraction efficiency can be precisely controlled, substantially independent of the particular process used to roughen the surface. Additionally, the selective roughening of the surface may be used to achieve a desired light emission output pattern.
Claims16
A method comprising:
- determining a target light extraction efficiency of a light emitting device;
- determining, based on an output function, a proportion of a roughened surface area to a not roughened surface area wherein the light emitting device emits the target light extraction efficiency when configured based on the determined proportion;
- applying a surface etch process on a light emitting surface to create the roughened surface area, wherein the roughened surface area relative to the not roughened surface area is based on the determined proportion, and wherein the light emitting surface is a top surface of the light emitting device that is not covered by a contact;
- applying an etch-inhibiting pattern on the light emitting surface to create the not roughened surface area, wherein the amount of the not roughened surface area relative to the amount of roughened surface area is based on the determined proportion, and wherein the area that is not roughened surrounds the roughened surface area.
A method comprising:
- determining a target light extraction efficiency of a light emitting device;
- determining that a proportion, X/Y, of a roughened surface area to a not roughened surface area results in the target light extraction efficiency for the light emitting device;
- applying a surface etch process on the light emitting surface to create the roughened surface area, wherein the roughened surface area relative to the not roughened surface area is X, and wherein a light emitting surface is a top surface of the light emitting device that is not covered by a contact;
- applying an etch-inhibiting pattern on the light emitting surface to create the not roughened surface area, wherein the not roughened surface area relative to the roughened surface area is Y.
Dependencies are inferred from the claim text.