The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 10, 2009
Filed:
Nov. 28, 2006
James Mckenzie, Flushing, GB;
Tom Lee, Basingstoke, GB;
Majd Zoorob, Southampton, GB;
Luxtaltek Corporation, Chunan, Miaoli County, TW;
Abstract
A light-emitting device (LED) is described which exhibits high extraction efficiency and an emission profile which is substantially more directional than from a Lambertian source. The device comprises a light generating layer disposed between first and second layers of semiconductor material, each having a different type of doping. An upper surface of the first layer has a tiling arrangement of pyramidal or frustro-pyramidal protrusions of semiconductor material surrounded by a material of different refractive index which together comprise a photonic band structure. The protrusions and their tiling arrangement are configured for efficient extraction of light from the device via the upper surface of the first layer and in a beam that is substantially more directional than from a Lambertian source An enhanced device employs a reflector beneath the second layer to utilize the microcavity effect. A method for fabricating the device is also described which employs anisotropic wet etching to produce the pyramidal or frustro-pyramidal protrusions