The United States has lost its world leadership role to Japan in optics, electron microscopes and stainless steels. Korea and Taiwan threaten U.S. leadership in man-made fibers, long the private province of the American chemical industry. American domination of the world's nuclear power industry has ended. Sweden, France, West Germany and Canada are now major forces in this high-technology business.

Is the United States losing its edge in technology? Is it suffering what some call an "innovation recession?" While there are signs that the U.S. has never been stronger technologically, there are other signs that the United States is lagging badly behind the rest of the world.

"There are trends that are worrisome," White House science adviser Frank Press said in an interview. "The research investments of American industry are up . . . but what are they spending it on? They are not develping the kinds of new products they were famous for."

One of the most striking examples of lagging U.S. technology lies in home video tape recorders business, where sales this year have doubled and are on the way to reaching $1 billion. Not one of the 12 machines sold in America today was made in America, even though the U.S. Broadcast industry pioneered the device. They are produced in Japan, even those trademarked RCA, GE, Zenith, Magnavox and Sylvania.

"The Japanese brought the machine down in size and price so the consumer could afford it," said an RCA executive who asked not to be named. "Sony and Panasonic focused all their technology on this machine and they now own the hottest market there is in the television industry today."

There are other signs to cause concern. The three largest chemical companies in West Germany last year introduced more new products than the five largest chemical companies in the United States. This is the first time that has happened since World War II. Japan now casts the largest steel ingots in the world, surpassing what American steel companies could do five years ago.

"The SST is French and British, the fast breeder (reactor) is French and Russian and the cameras we carry, the TV sets we watch and the cassettes we listen to are Japanese," says General Electric Co.'s Dr. Ivar Giaever, a Nobel laureate in physics. "It's no wonder we're all worried."

So worried is the White House that it has split 100 technological leaders into six task forces to assess where the United States stand among the world's innovators. Their conclusions will be passed on for review to 28 federal agencies and then to universities and other interested groups for comment.

"If we're losing our edge, we want to know where we're losing it and why we're losing it," said Press. "What I think this study will show is that we're strong in high technologies like aircraft and computers and not so strong in middle-level technologies like chemicals and electrical machinery."

Statistics tell a confusing tale. Fewer patents were granted by the U.S. Patent Office to Americans last year than at any time in the past 15 years, but in the field of electronics where invention is commonplace, fewer scientists are applying for patents.

"An invention in electronics can be obsolete in the two or so years it takes to be patented," says Science magazine this week. "By that time, the company filing the patent can have lost whatever edge it had by developing the thing in the first place."

The Commerce Department points out that American exports of products requiring a low or middle level of technology grew from $14 billion in 1968 to $36 billion in 1974. But Japanese exports of similar products frew from$9 billion to $35 billion while Germany raised it esport total from $16 billion to $54 billion in the same period.

At the same time, the United States came out well in the battle for exports labeled "technolgoy intensive." The U.S. total was $9.6 billion in 1968 and $26.6 billion in 1974. Japan's total in 1974 was $13.2 billion and West Germany's was $22 billion.

The National Science Foundation points out that the United States dominates the worldwide electronics industry despite Japan's take over of the radio and television markets. The pocket calculator is an American invention. So is the digital watch, whose sales last year were almost $2 billion worldwide. Digital watches now make up one third of the $2.8 billion U.S. watch marked.

A lot of people fussed when the European airbus made inroads into the jetliner market the United States once had to itself," the NSF's Dr. Alton Bean said. "But don't forget the engines on that airbus are American and don't forget that the airbus is a twin-engined wide-body jet designed for the European market. The tri-jet the United States makes still has most of the wide-body market."

Nevertheless, there are still disquieting signs of an U.S. innovation recession. The question is why. Massachusetts Institute of Technology President Jerome B. Wiesner blames it on the thaw in the Cold War and a new skepticism in the Congress about spiraling research budgets, especially in the field of medicine and health.

"There were two things that made research grow in this country in the 1950s and 1960s - "The Cold War and Congressional support of national health research," Wiesner said.

The end of the Appolo program that put 12 men on the moon is also a cause of research decline, as is the end of the Vietnam was, where American weaponry was often inspired by Pentagon research. Some scientists believe the antinuclear movement and increasing hostility toward technology are also behind the innovation recession.

Many blame an oudated patent policy that does not provide enough protection to inventors and federal regulation that slows new product development.

More subtle reasons include impatience to wait the 5 to 10 years for a new product to develop from research. N. Bruce Hannay, vice president or research for Bell Telephone Laboratories explained; "I see on the research scene a greatly shortened time horizon. As a result, there is a decline in the effort on major innovation that produces an entirely new class of technology or a new class of service."