Seven companies have been fined almost 1.5 billion euros (£1.22 billion) by the EU for rigging the market in television and computer monitor tubes for a decade ending in 2006.
The EU's Commission ruled that, for a decade ending in 2006, the companies - including Philips, LG Electronics and Panasonic - artificially set prices, shared markets and restricted their output at the expense of the consumer.
EU anti-competition commissioner Joaquin Almunia said that the companies' actions "feature all the worst kinds of anti-competitive behaviour that are strictly forbidden to companies doing business in Europe."
Tubes were the essential part of television screens and computer monitors before they were replaced by flatscreens. The cathode ray tubes accounted for up to 70% of the cost of a screen, the Commission said.
Mr Alumina added that the tubes' cost gave "an indication of the serious harm" the companies had caused.
Other companies fined were Samsung SDI, Technicolour, MTPD and Toshiba. Chunghwa of Taiwan escaped fines as it was the first to reveal the cartel to the EU.
"It is the biggest fine for a cartel, ever," Mr Almunia said.
He said the tubes cartel operated worldwide with the companies involved fully realising they acted illegally.
One document seized by the Commission had a warning "Everybody is requested to keep it as secret as it would be serious damage if it is open to customers or European Commission."
Another said "Please dispose the following document after reading it."