A federal appeals court has affirmed a lower court ruling that Virginia inventor Gordon Gould is entitled to a patent for the gas-discharge lasers he designed more than 20 years ago at Columbia University.

The ruling last week by the 9th U.S. Circuit Court of Appeals may force commercial laser firms and users to pay millions in new licensing fees to Gould and Patlex Corp. of Chatsworth, Calif.

Patlex Corp. holds a 64 percent interest in Gould's laser patent properties.

The ruling was another major victory in a long battle that Gould has been waging with the U.S. Patent Office.

Gould, who now lives in Kinsale, Va., first applied for a patent on lasers in 1959.

Gould came up with a design for a laser device in the late 1950s while a graduate student at Columbia. He contends that he is the first inventor of the laser, but many experts credit instead Charles Townes, a former Columbia professor and now a professor emeritus at the University of California, Berkeley, and Arthur Schawlow, a professor of physics at Stanford University.

Gould and Patlex have won other legal battles that they have waged over his laser devices.

Last month a U.S. District Court jury found that Cooper Lasersonics of Santa Clara, Calif., has infringed on Gould's patent for a copper-vapor laser amplifier.

In that case, Gould and Patlex were awarded $160,000.

Patlex said that if the patent office issues a patent for a gas-discharge laser to Gould, who already owns a patent on the optically pumped laser, the two patents would cover 85 percent of laser devices used in the United States.

Sales of laser systems totaled more than $500 million last year.