OLED TV Manufacturers
Sony gave the lead, manufacturing the first OLED TV available to consumers. At this point, they are the only brand offering this type of display to consumers. Sony is putting a significant amount of resources into OLED technology, trying to stay ahead of the other manufacturers. They currently build high-quality LCD TVs (some of the best on the market) and soon they will mass produce the next best display technology – OLED.
Samsung comes fast from behind. They lacked the initiative but that doesn’t mean they want to miss the opportunity OLED is offering. Samsung already presented what we can consider large screens – two OLED TV prototypes, one measuring 17 inch and the other 40 inch. Samsung’s technology is different though, in a way resembling LCD technology. Their OLED prototypes have a white light emitter and a color filter as opposed to Sony displays that uses red, green and blue sub-pixels to produce colors and light.
While Sony and Samsung seem to lead the way, other manufacturers also present interest in OLED. Among them are Phillips, LG and Matsushita which is behind Panasonic (one of the top plasma TV manufacturers). About Pioneer, the manufacturer that produces best plasma TVs on the market at this point, we don’t know much. Their plasma TVs are not too far behind current OLED TVs in terms of picture quality so maybe they are not in a hurry to jump the OLED wagon as others do. Only time will tell for sure, though.

which companys stock should one invest in if the technology is going to take off.
@kevin davison: I would say Sony and Samsung. They seem to to focus the most on OLED.