A Michigan scientist says he has invented a new class of materials that can economically convert sunlight to electricity and -- with sufficient financial support -- could be available commercially in a few years.

The discovery, unveiled by Stanford R. Ovshinsky at a New York City press conference and in the pages of Nature, a prestigious British scientific publication, has been met with caution by the Energy Department and a number of scientists, competitors and investors.

Ovshinsky says that within three years the company he heads, Energy Conversion Devices Inc., could begin mass production of solar cells that would be competitive with electric current generated from fossil fuels and nuclear energy.

A controversial figure in investment circles, Ovshinsky says development of the new electronic material "is a matter of investment and priority."

While full details have not been made public, Ovshinsky says his new material is a mix of amorphous silicon, fluorine, and other ingredients such as hydrogen. Amorphous materials have no coherent internal structure, in contrast to the crystalline form of almost pure silicon used in most solar cells now being produced.

It costs from 50 cents to a $1 or more to produce one kilowatt hour, from crystalline solar cells compared with 2 to 9 cents a kilowatt hour for conventionally generated electricity.

Ovshinsky, 56, said that his cell would produce electricity at about 5 cents a kilowatt hour.

At the Energy Department yesterday, Rhett Turnipseed, a solar programs official, said: "DOE's photovoltaic program analysts do not believe he (Ovshinsky) has completely demonstrated the efficiency of his cell yet."

Monday Ovchinsky will meet with DOE officials here to explain his invention.

"We're not asking for anything," Ovshinksy said in a telephone interview. "We are just having discussions to see whether there is a possibility of doing something."

Thus far Energy Conversion Devices has not participated in any of DOE-funded solar research programs that now account for $500 million of the department's budget.

During a press conference in New York Thursday, Ovshinsky said he would need about $10 million to begin production of his new cell.

Significant strides have been made in photovoltaic technology in recent years, but industry and government are still looking for a breakthrough that would enable them to slash the costs of production. Ovshinsky, a self-trained scientist, says his invention would allow the production of a thin film, 1 micron thick, that could be mass produced.

Yesterday on Wall Street there was mild interest following ECD's announcement, with the company's stock rising 2 1/2 points to 17 3/4. Following a 1968 announcement about a semi-conductor discovery, ECD shares rose 30 points, eventually peaking at well over 100.

One security analyst said yesterday, "It is not a fraud by any means, but so far there is nothing to base an investment on yet."