Lumileds asserts AlGaInP patents against UEC and Epistar

US-based LED maker Lumileds Lighting has initiated litigation for patent infringement against two rival Taiwanese LED manufacturers, Epistar Corporation and United Epitaxy Co., Ltd (UEC). Epistar and UEC are in the process of merging.

Lumileds has filed a complaint against both companies at the US International Trade Commission (ITC), alleging that the companies' wafer bonded AlGaInP LED products infringe certain patents owned by Lumileds.

Specifically, Lumileds accuses Epistar's omnidirectional mirror adhesion (OMA) AlGaInP LED products and UEC's metal bond (MB) and glue bond (GB) AlGaInP LED products of infringing one or more of Lumileds' US patents: no. 5,008,718; no. 5,376,580; and no. 5,502,316.

In response, Epistar and UEC said (according to the Digitimes website) that their respective OMA, MB and GB AlGaInP LED product lines "have no patent disputes" and that they have not received any written notification from Lumileds regarding patent violations. When merged, the companies will share more than 20 patents relating to these device types.

Wafer-bonding processes

AlGaInP LED structures are grown on GaAs substrates, but the GaAs material absorbs light, reducing the efficiency of this type of device (referred to as "absorbing substrate" or "AS" LEDs). One solution is to use a wafer-bonding process to replace the GaAs substrate with a GaP wafer to make a "transparent substrate" or "TS" LED.

UEC's MB technology The Epistar and UEC device structures referred to above generally replace the GaAs substrate with a structure which helps to direct downward-emitted light back towards the top of the device, from where it can leave the device rather than being absorbed.

Lumileds has previously reached patent licensing deals with both Epistar and UEC covering AS AlGaInP LEDs. However, Lumileds has not licensed its TS technology and the two Taiwanese companies developed their OMA, GB and MB technologies in response. Earlier this year, Lumileds indicated that it would challenge competitors with products using "mirror substrate" technology (see IP thieves beware, warns Lumileds).

In its ITC complaint, Lumileds seeks an exclusion order barring entry into the United States of the accused LEDs as well as products containing those LEDs.

Lumileds also filed a complaint in the United States District Court for the Northern District of California for patent infringement against UEC and Epistar. In that complaint, Lumileds asserts the same patents against UEC and Epistar as in the ITC litigation. Lumileds seeks both an injunction against future infringement as well as damages, including enhanced damages for willful infringement.

"Lumileds holds more than 100 patents in the area of high-brightness and high-power LEDs," said Mike Holt, Lumileds' CEO. "We will continue to enforce our intellectual property rights."