EU regulators are set to fine LG Display, Chi Mei Optoelectronics Corp and three other firms up to 700 million euros ($928 million) in total for fixing prices of display panels used in consumer devices, a source close to the case said on Monday.

The European Commission, the EU antitrust watchdog, charged the companies in July last year with breaching EU laws on restrictive business practices, while other regulators around the world have also investigated the sector.

The total fine will be between 600 and 700 million euros, the source told Reuters.

The EU executive will levy the biggest fine on Taiwan's Chi Mei, the source said, declining to provide details of the individual fines.

Chi Mei paid $220 million in fines last year after pleading guilty to U.S. charges of price-fixing. The company later merged to form Chi Mei Innolux, a combination which now comprises Taiwan's largest maker of LCD panels.

The Commission is expected to announce its decision on Wednesday, sources told Reuters previously.

The Commission can penalize companies up to 10 percent of their global turnover for infringing EU laws.

The watchdog did not identify the companies at the time, but LG Display, 3 AU Optronics and Chi Mei confirmed the charges.

Taiwanese firms Chunghwa Picture Tubes and HannStar Display Corp were also named in a Commission document obtained by Reuters.

World No.1 LCD maker Samsung Electronics will not be fined as it alerted the Commission to the cartel.

Dutch company Philips received a copy of the charge sheet as a former shareholder of LG Display, but said it was not directly involved. It sold the rest of its shares in the joint venture with LG Electronics in March 2009.

The EU Commission's case had centered on thin-film liquid crystal display panels used in computers, mobile phones, televisions, digital watches, pocket calculators and MP3 players.

In the U.S. Department of Justice investigation, eight companies, including LG Display, Chi Mei, Chunghwa, Japanese company Sharp Corp and Hitachi Displays, paid more than $890 million in criminal fines for price-fixing.

Japan's Fair Trade Commission slapped fines on Sharp Corp and Hitachi Ltd in 2008 for price fixing in the market for LCD panels.

(Editing by Rex Merrifield and David Holmes)

($1=.7541 Euro)