[IMID 2018] LG Display, 수명을 개선한 자동차용 OLED로 2 stack RGB OLED 선보여

829일 부산 BEXCO에서 열린 IMID 2018에서 LG Display의 김관수 연구위원(research fellow)은 자동차용 디스플레이에 적용될 새로운 OLED 기술에 대해 발표했다.

김 연구위원은 현재 모바일 기기에 적용되고 있는 RGB OLEDTV에 적용되고 있는 WRGB OLED는 수명 측면에서 고객사들의 요구를 만족시키지 못하고 있기 때문에, 이를 해결하기 위한 방법으로 RGB OLEDWRGB처럼 tandem 구조를 갖는 2 stack RGB OLED를 소개했다.

2 stack RGB OLED는 다층구조에 CGL(charge generation layer) 층이 더해져 두께가 두꺼울 수 있기 때문에 HTL을 기존보다 얇게 만들고 발광층의 charge balance를 최적화하였다.

그 결과 1 stack RGB OLED보다 1.5배에서 2배 향상된 발광효율과 함께 수명이 T80 기준으로 4배 이상 증가하는 효과가 나타났다고 보고했다.

하지만 2 stack 구조는 일반 구조에 비해 소비 전력이 높은 단점이 있어 이를 해결하기 위한 노력이 필요하다고 지적했다.

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.

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<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.

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<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.

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