This patent had been the subject of a Patent Office re-examination requested by a competitor. It is one of five International Rectifier patents previously held valid and infringed in a federal district court action in 1990.

This decision led to an injunction against a competitor who subsequently entered into a royalty-bearing license agreement under the patents. The Court of Appeals for the Federal Circuit later upheld a favorable construction of the scope of the patent in a proceeding brought by International Rectifier to enforce one of its other license agreements.

The latest ruling serves to support the royalty rates payable to International Rectifier under its current licensing agreements and sets the stage for additional agreements with as-yet-unlicensed competitors. The ‘666 patent will expire in March 2000, along with its parent patent 4,376,286.

The same Patent Office board is now reviewing two other International Rectifier power transistor patents, which expire in 2007 and 2008, respectively. According to the company, issues similar to those that formed the basis for re-affirming the ‘666 patent also underlie the review of those patents.

While no assurance can be given as to the ultimate outcome of those reviews, the company believes that this recent decision bodes well for timely and favorable rulings.

Currently more than 20 competitors have entered into licensing agreements under International Rectifier’s power MOSFET and IGBT patents.

International Rectifier is a major worldwide supplier of components and subsystems that convert electrical power to operate power supplies, motor drives, and lighting ballasts. Its patented HEXFETR power MOSFETs and IGBTs make IR the world leader in field effect transistors.

IR’s technological advances improve the performance and energy efficiency of electronic and electrical equipment in automotive, consumer, computer/peripheral, industrial, lighting, telecom, and government/space applications.