Luminescent ceramic for a light emitting device

US7361938B2 · kind B2 · utility

Assignee

• Philips Lumileds Lighting Company LLC · US

Inventors

• Gerd O. Mueller · San Jose, US
• Regina B. Mueller-Mach · San Jose, US
• Michael R. Krames · Los Altos, US
• Peter Josef Schmidt · Aachen, DE
• Hans-Helmut Bechtel · Roetgen, DE
• Joerg Meyer · Wagenfeld, DE
• Jan De Graaf · Uden, NL
• Theo Arnold Kop · Haarlem, NL

Key dates

• Filing date: Jun 3, 2004
• Grant date: Apr 22, 2008
• Expiry date: Jun 3, 2024

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10H20/8583
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

A semiconductor light emitting device comprising a light emitting layer disposed between an n-type region and a p-type region is combined with a ceramic layer which is disposed in a path of light emitted by the light emitting layer. The ceramic layer is composed of or includes a wavelength converting material such as a phosphor. Luminescent ceramic layers according to embodiments of the invention may be more robust and less sensitive to temperature than prior art phosphor layers. In addition, luminescent ceramics may exhibit less scattering and may therefore increase the conversion efficiency over prior art phosphor layers.