LIGHT EMITTING DIODE WITH IMPROVED LIGHT EXTRACTION EFFICIENCY

• Main Authors: MUELLER-MACH REGINA B, HOFLER GLORIA E, CAMRAS MICHAEL D, SNYDER WAYNE L, KRAMES MICHAEL R, STERANKA FRANK M, TROTTIER TROY A, TABER ROBERT C, UEBBING JOHN J, POCIUS DOUGLAS W, LOWERY CHRISTOPHER H, MUELLER GERD O
• Format: Patent
• Language: English
• Published: 17.05.2002
• Edition: 7
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; SEMICONDUCTOR DEVICES

PROBLEM TO BE SOLVED: To provide a light emitting device having a stack of a layer containing a semiconductor layer including an active region and improved light extraction efficiency. SOLUTION: The light emitting device with improved light extraction efficiency is provided. The device has a stack of layers including semiconductor layers having an active region. The stack is bonded to a transparent optical element having a refractive index for the light emitted by the active region preferably greater than about 1.5, or preferably grater than about 1.8. A method of bonding a transparent optical element (e.g. a lens or an optical concentrator) to a light emitting device comprising an active region includes a step of elevating the temperature of the optical element and the stack and a step of applying pressure to press the optical element and the light emitting device together. A block of optical element material may be bonded to the light emitting device and then shaped into an optical element. Bonding a high refractive index optical element to a light emitting device improves the light extraction efficiency of the light emitting device by reducing the loss due to total internal reflection.