It's unusual for a lone inventor to sue a big corporation for alleged patent infringement. But when, after a long legal struggle, the corporation settles with the inventor after the first day of trial, it's cause for celebration. And that's exactly what 61-year-old Cortland O. Dugger of Upper Marlboro is doing these days.

"I feel justice has been done," says Dugger, musing on the culmination of events that began in 1959 when he worked as a solid state research chemist in an Air Force laboratory in Cambridge, Mass.

Dugger had prepared for that career by earning a bachelor's degree in biology and chemistry at Tufts University in 1950 and obtaining two master's degrees, in materials science from Boston's Northeastern University and in business management from Central Michigan University. While in the Navy, he was a pharmacist's mate in World War II and in the Korean war.

After working as a research chemist at the Massachusetts Institute of Technology, the Medford, Mass., native became a civilian research scientist with the Air Force.

During that time, he developed a material called barium magnesium aluminate, a phosphorite base material for activators that can cause material to fluoresce and be used in light bulbs (and which turned out to be very valuable for the fluorescent lamp industry). His boss dubbed the material "Duggerite."

Dugger applied for a patent and was granted all commercial rights while the government maintained the nonexclusive right to use the material. In 1981, Dugger left the government and moved to the Washington area to join GTE Laboratories Inc., a subsidiary of GTE Products Corp., where he was a technical marketer for government contracts.

One day, during a routine program review, he said, he heard mention made of the material he had invented. Turning to a director sitting beside him, he exclaimed, "I discovered that material!" According to Dugger, the man made no reply.

Dugger called the patent office of GTE and asked what it had in patents for phosphor materials that were part of the fluorescent tubes manufactured and sold by GTE Products. "When they sent me documents, it included my chemical formulation," he said. But the company denied that it was infringing on his patent or using his material.

Leaving the company, Dugger started making the rounds of patent lawyers. "I had to find a patent firm that would take my case on a contingency basis. I went to half a dozen who said no before I found one -- Millen and White in Arlington -- who said yes. I'm not so sure they believed what I was saying when I first got started, but once they were convinced, they followed through with vigor."

Dugger's attorneys, William Millen and John White, said later, "We don't know of any black inventor suing a corporation." They were also impressed with the distinguished Massachusetts family from which Dugger hailed. His brother, the late Edward Dugger Jr., a 1941 Tufts engineering graduate, was national champion in high hurdles events for 11 years. He was an engineer at Wright Patterson Air Force Base, where an auditorium was named for him. A sister, Ione D. Viagus Adams, is a dean at Temple University.

Dugger's late father, Edward Sr., was a first lieutenant in World War I and became acting commanding officer of his infantry regiment in France. Later he was a Boston police officer and civic activist. Dugger Park in Medford bears his name in recognition of his contributions.

Madeline Dugger Kelley, Dugger's 91-year-old mother, is a 1933 graduate of Portia Law School in Boston and was a legal adjudicator for the Veterans Administration. In 1952, the mother of six was voted Massachusetts Mother of the Year. Equally accomplished is Dugger's wife, Eva King Dugger, associate chairman and acting chairman of the department of nutrition at Howard University's College of Allied Health.

But Millen and White told Dugger that he needed evidence that GTE was using his materials, because the company continued to deny his claim. Purchasing some of GTE's material, Dugger had it analyzed by several experts. When the company persisted in denying the claim, Dugger and his attorneys decided to go to court.

Two weeks ago, Dugger met GTE in federal District Court in Alexandria. After the first day of trial, the company decided to settle the suit. The amount of the settlement and other details were withheld as a condition of settlement, but Dugger isn't complaining. "All things considered," he said, "I think the settlement is as equal as I'm going to get."