High ambient-contrast-ratio display using tandem reflective liquid crystal display and organic light-emitting device

Jiun-Haw Lee, Xinyu Zhu, Yi-Hsin Lin, Wing Kit Choi, Tien-Chun Lin, Sheng-Chih Hsu, Hoang-Yan Lin, Shin-Tson Wu
2005 Optics Express  
A high ambient-contrast-ratio (A-CR) and large aperture-ratio display is conceptually demonstrated and experimentally validated by stacking a normally black reflective liquid crystal display (NB-RLCD) and an organic light-emitting device (OLED). Such a tandem device can be switched between the NB-RLCD mode and the OLED mode under bright and dark ambient light, respectively. The normally black characteristic of the RLCD also helps to boost the A-CR under OLED-mode operation. To obtain a better
more » ... age quality in the RLCD mode, a bumpy and transmissive structure is used to eliminate the specular reflection and to increase the viewing angle performance that results in CR>2:1 over 55 o viewing cone. Besides, such a structure can also increase the external quantum efficiency of the OLED by 49.4%. In our experiments, regardless of the ambient intensity the A-CR is kept higher than 100:1.
doi:10.1364/opex.13.009431 pmid:19503145 fatcat:7ff4mi7tbbcdvpph3b3uhl7lra