Newly Invented LG Display Device Said to Overcome Limits of White OLED

A team of six LG Display engineers invented a newly structured OLED display device designed to overcome the color reproduction and efficiency limitations of conventional white OLED technology, said a U.S. patent application (20200411787) filed Sept. 9 and published Thursday at the Patent and Trademark Office. The newly invented OLED display device “comprises two emission portions between first and second electrodes,” in which at least one of the emission portions includes two emitting layers, boosting efficiency and the color reproduction ratio, it said. An organic light-emitting diode emitting white light in a conventional OLED display contains a structure of two emitting layers in which “colors are complementary to each other,” said the application. This structure generates a difference between a wavelength area of an electroluminescence peak of each emitting layer and a transmissive area of a color filter when white light passes through, it said. The structure makes it “difficult to obtain a desired color reproduction ratio,” it said. The inventors “have recognized the aforementioned problems” and devised an OLED display device “of a new structure,” it said. The structure’s first emission portion includes a green-emitting layer and a red-emitting layer, while the second emission portion includes a dark blue-emitting layer, it said.