The man who invented Flash memory is suing his former company, Toshiba, for ¥1 billion (£5m).

Fujio Masuoka, who worked at Toshiba's research and development center from 1971 before joining Tohoku University in 1994, and who is widely credited with inventing one of the most common types of electronic memory, claims he has not received adequate compensation for his work.

The Nihon Keizai Shimbun newspaper has reported that court documents claim Toshiba's cumulative profit to 2003 from the 21 patents associated with Masuoka is around ¥20 billion (£100m). Masuoka, who still teaches at Tohoku University, could not be reached for comment. Toshiba declined comment, saying it has not yet seen the complaint, which was filed at the Tokyo High Court yesterday.

Flash memory is widely used in many electronic and computer products because it has the ability to hold data when no power is being supplied. Products such as cellular telephones, and almost all of the memory cards in use today in portable products, are based on flash memory.

The news comes shortly after three Japanese court cases resulted in awards of significant amounts to inventors.

In late January, the Tokyo District Court ordered Nichia to pay ¥20 billion in compensation to Shuji Nakamura for his invention of the blue LED. Nakamura, who is now a professor of engineering at the University of California, Santa Barbara, received ¥20,000 (£99) for the invention at the time.

A day before the Nichia ruling, Hitachi was ordered to pay ¥163 million (£800,000) to a former researcher in connection with compensation for the development of technology related to optical discs. And last week, food company Ajinomoto was ordered to pay ¥189 million (£937,000) to a former employee in compensation for the development of the Aspartame artificial sweetener.

Last week, Toshiba Chairman Taizo Nishimuro took issue with the Nichia ruling. "The decision of the judge from our viewpoint is outrageous," he said, speaking in his capacity as a vice-chairman of Nippon Keidanren (Japan Business Federation). "It's true that the invention has great value but to make it possible is the effort of the corporation and other people working for the corporation. As far as product innovation is concerned, innovation cannot be created by one person."