TOKYO, Dec 25 (Reuters) - Sony Corp 6758.T and Panasonic Corp 6752.T , Japan's two largest consumer electronics companies, said on Wednesday that they will end joint development of organic light emitting diode (OLED) television screens, a thinner and brighter type of next-generation display in which Korean rivals have a head-start.

The two companies, which have been scaling back their TV operations after chalking up heavy losses in recent years, will instead focus their efforts on conventional liquid crystal display screens for so-called 4K ultra high-definition televisions which have shown greater promise, company spokesmen said.

Sony and Panasonic formed the OLED alliance in June last year with the goal of developing mass-production technology by the end of 2013. Doubts had mounted over the partnership's prospects, however, as it became clear it would miss its target.

OLED panels, while used in smartphones and tablets by Samsung Electronics Co Ltd 005930.KS , are still considered prohibitively expensive for larger sizes used in televisions.

They have not delivered the growth originally envisioned by the Japanese companies and are unlikely to be commercially viable in the near future, the spokesmen said.

Both companies displayed 56-inch OLED televisions at this year's CES electronics show in January. The spokesmen said they would continue independent efforts to develop OLED technology.

LG Electronics Inc 066570.KS , considered the front-runner in OLED televisions, has models on the market but they are significantly more expensive than comparable LCD televisions and have yet to achieve significant sales. Samsung also markets OLED televisions, which offer higher resolution and use less power than LCD panels.

(Reporting by Reiji Murai; Writing by Edmund Klamann; Editing by Robert Birsel)

((edmund.klamann@thomsonreuters.com)(+813 6441 1841)(Reuters Messaging: Reuters Messaging: edmund.klamann.thomsonreuters@reuters.net))

Keywords: SONY PANASONIC/