DisplaySearch published an article recently citing a few reasons why mass production of 4K LCD TVs is likely to happen before OLED displays.
Samsung and LG have been aggressively marketing their OLED TVs at major tradeshows since CES and IFA 2012. Both companies are touting 55-inch Full-HD OLED screens, although their technologies are dissimilar in comparison. Fundamentally, LG employs a 4-color pixel WRGB OLED arrangement, while Samsung's solution is based on a 3-color pixel RGB OLED cell structure. The challenges of mass producing OLED panels, however, lie with the TFT backplane as well as the evaporation of organic materials and its encapsulation process.
To compound this, both firms are still uncertain when mass production cycles of their OLED panels will commence. Samsung and LG have yet to provide a definite timeline to date. Cost is another factor, since a 55-inch OLED TV is likely to cost two to three times more than a conventional LCD TV with LED backlights of the same size, and this may prove to be a major stumbling block with consumer adoption during OLED's teething phase.
On the other hand, panel manufacturers are already stepping up their production runs for 4K LCD TV panels, including Samsung and LG themselves. Other brands include Sharp, AUO, and Chimei Innolux, who are said to be preparing 4K LCD panels ranging from 50 to 84 inches.
Meanwhile, Samsung, LG, Sony, Sharp, Toshiba, Hisense, Haier, Changhong, TCL, and Konka have also announced 4K LCD TV products.
Broadcasters are also taking this cue to churn out more 4K content. Titles such as "The Girl with the Dragon Tattoo" and "Moneyball" have published by Hollywood. And with panel makers wanting to "move" consumers to larger screens beyond the 50-inch mark, an UItra High-Definition screen would make more sense than a slim Full-HD OLED TV under these circumstances.