AMSTERDAM (Reuters) - Two British companies said on Monday they would join forces to become a world leader in the technology of glowing plastics, which by 2005 should yield the first roll-up computer screens and TVs.

Cambridge Display Technology (CDT) announced the acquisition of the Oxford-based research activities of rival Opsys, giving it control of another major method to create organic light emitting diodes (OLED). Financial details were not disclosed.

The two unlisted companies sell their know-how to major electronics manufacturers, such as Seiko Epson, Philips, DuPont and Siemens-owned Osram, some of whom have just opened factories for the first generation of monochrome OLED displays used in cell phones and razors.

As the technology matures it will be used for full-color screens. CDT is taking on U.S. photo giant Eastman Kodak, which is one of the pioneers of OLEDs. The Cambridge University spin-off claims to have found a more efficient production method, which effectively prints a special type of OLED on a surface.

The market for OLEDs is expected to rise from just $85 million this year to $3 billion by 2007, according to a recent survey of U.S. market research group DisplaySearch.

Hopes for the technology are high because polymers that emit light do not require a backlight used for the current generation of flat screen liquid crystal displays (LCDs). It makes them energy efficient and much thinner -- so thin they can be folded. Opsys, spun out of Oxford and St Andrews Universities in 1997, uses new polymers, called dendrimers, which are brighter and more energy efficient than CDT's light-emitting polymers (LEPs). The two companies hope to blend their technologies to improve the lifetime of the dendrimers.

CDT Chief Executive David Fyfe said he expects that by 2005 the technology will be mature enough, and the price per display competitive enough, so that OLEDs will start replacing current LCD full-color flat screens, which recently started replacing 70-year old cathode ray tube technology.

"The attraction is that (OLEDs) are much more energy efficient. It doesn't generate as much heat and the light goes only in one direction," he said.