Low profile side emitting LED

US7626210B2 · kind B2 · utility

Assignee

• Philips Lumileds Lighting Company LLC · US

Inventors

• Oleg Borisovich Shchekin · San Francisco, US
• Mark Pugh · Coolaney, IE
• Gerard Harbers · Sunnyvale, US
• Michael R. Krames · Los Altos, US
• John E. Epler · San Jose, US

Key dates

• Filing date: Jun 9, 2006
• Grant date: Dec 1, 2009
• Expiry date: Oct 12, 2027

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10H20/856

Abstract

Low profile, side-emitting LEDs are described, where all light is efficiently emitted within a relatively narrow angle generally parallel to the surface of the light-generating active layer. The LEDs enable the creation of very thin backlights for backlighting an LCD. In one embodiment, the LED is a flip chip with the n and p electrodes on the same side of the LED, and the LED is mounted electrode-side down on a submount. A reflector is provided on the top surface of the LED so that light impinging on the reflector is reflected back toward the active layer and eventually exits through a side surface of the LED. A waveguide layer and/or one or more phosphors layers are deposed between the semiconductor layers and the reflector for increasing the side emission area for increased efficiency. Side-emitting LEDs with a thickness of between 0.2-0.4 mm can be created.