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OLED TV continuing to evolve

At the ‘4th 2018 OLED Korea Conference’ hosted by UBI research on March 7-8, Dr. Han Chang-Wook, Chief Research Fellow of LG Display, made a presentation for the development process of OLED TVs and emphasized the image quality of OLED, design flexibility and expandability.

At first, Dr. Han introduced three core technologies including TFT technology, OLED stack technology, and compensation circuit design applied to OLED TVs. He said, “We changed the TFT as top gate coplanar structure for UHD implementation in bottom gate TFT applied to FHD.” He also mentioned “We changed the WRGB OLED pixel structure from 2 stack structure to 3 stack structure to improve the luminance and color reproduction ratio, and designed the compensation circuit so that it does not affect the OLED even on 8K large screen.”

He commented, “Unlike LCDs that control pixels with local dimming, OLEDs have pixel dimming controls, which allows for full black representation and less halo effects”

Explaining that OLED allows greater design flexibility and expandability because of the self-illuminating properties that does not require backlight, he referred to the mirror display and transparent display applicable to indoors, and the world’s first 88 inch 8K OLED TV and 65 inch rollable OLED TV exhibited at CES 2018.

Dr. Han said “We expect large OLED panel production to be tripled, compared to 2016, with the expansion of production lines and yield improvement in 2018. In addition, the company will be able to ship over 6 million large area OLED panels by 2020 through the expansion of its Paju and Guangzhou plants.” He also announced that the company will increase continuously the production for OLED panels, which were 5% of the total display panels in 2016, by 40% by 2020.

LG Display, announcement on development trend for OLED TV and latest WOLED device for lighting in IDW 2016

In IDW(International Display Workshops) 2016 held in Fukuoka Japan from December 7~9, LG Display announced on the development trend for OLED TV and latest WOLED device for lighting, and mentioned that the color area of latest WOLED device for OLED TV increased from 114% to 129% compared to sRGB, and 90% to 99% compared to DCI. In the paper, 3 stack structured 55” UHD OLED TV shows 150cd/m2 in full white screen, 500cd/m2 of luminance in peak white screen, and showed that it lowered the power consumption by 20% compared with 2 stack structure.

<LG Display’s 2 stack and 3 stack WOLED lighting structure, IDW 2016>

Also by introducing WOLED for lighting, LG Display mentioned that lighting WOLED has 3 stack tandem structure with green-red/blue/green-red, where WOLED for OLED TV has 3 stack tandem structure with blue/yellow-green/blue. It showed high efficiency of 90lm/w by applying Ag cathode and light extraction film which the reflectivity is high, and the color temperature is 2,850K which is in the warm white range, CRI showed characteristics of 88. This OLED light will start its production in 3rd quarter of 2017 in 5 generation line.

<LG Display’s 2 stack and 3 stack WOLED light structure which applied light extraction film, IDW 2016>

Meanwhile, LG display exhibited 800 nit 65” UHD OLED TV during OLED summit 2016 held last September in San Diego where they gained much interest compared to 65” curved QD-LCD TV quality, and it is expected that they will introduce OLED TV with improved luminance with more than 1,000 nits next year.

<Comparison of black quality between 65inch OLED TV(left) and 65inch curved QD-LCD TV(right), LG Display, OLED Summit 2016>