A judge has certified a class action lawsuit against Samsung, Sharp and other makers of liquid-crystal display panels for allegedly conspiring with each other to fix prices and overcharge customers. The class action suit was filed on behalf of customers who purchased televisions, computer monitors and laptops containing the flat-screen displays or other LCD products from 1999 to 2006.

The class action suit will undoubtedly add more financial worries for LCD makers, who have been fined almost $1 billion since 2008 after six LCD makers plead guilty to price fixing in a U.S. criminal investigation. A European investigation is pending.

According to BusinessWeek.com, Sharp, Hitachi, Epson and Chei Mei Optoelectronics have pleaded guilty in the U.S. investigation. Samsung, the world’s largest LCD maker, hasn’t pleaded guilty to price fixing.