| Co-Investigator(Kenkyū-buntansha) |
MIYASHITA Tetsuya GRADUATE SCHOOL OF ENGINEERING, TOHOKU UNIVERSITY, ASSISTANT PROFESSOR, 大学院・工学研究科, 助教授 (10239402)
SEKI Hidehiro DEPARTMENT OF ENGINEERING, HACHINOHE INSTITUTE OF TECHNOLOGY, PROFESSOR, 工学部, 教授 (30134018)
FUKUDA Ichiroh DEPARTMENT OF ENGINEERING, KANAZAWA INSTITUTE OF TECHNOLOGY, PROFESSOR, 工学部, 教授 (10064445)
KAWAKAMI Tohru GRADUATE SCHOOL OF ENGINEERING, TOHOKU UNIVERSITY, RESEARCH ASSOCIATE, 大学院・工学研究科, 助手 (90282102)
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| Research Abstract |
Reflective type liquid crystal displays (LCDs) have advantages of thin shape, light weight and low power consumption, while it was considered to be quite difficult to achieve sufficient brightness in reflective color LCD because of large absorption of the color filter. Then, we have already solved this problem by increasing the viewing angle of liquid crystal extremely and by collecting the reflected light into a certain angle range.
In this research, in order to realize a high performance reflective LCD with full color moving image, R-OCB mode with active-matrix-drive is adopted. We aimed to establish a theory of the optical designing and optimization of the liquid crystal panel, optical retardation films and polarizers. For this purpose, we newly proposed theoretical expression focusing on optical properties of the above mentioned elements. In this method we have succeeded to express the wavelength dependence and viewing angle dependence of each element by simple diagrammatic method.
By using this expression, almost all the optical characteristics of display can be treated theoretically and all the parameters to design the reflective display can be optimized and determined. As the result, we have designed an extremely high performance reflective LCD with high brightness, achromatic while in wide viewing angle range and very good dark state or very high contrast ratio in wide viewing angle range.
Finally, based on the above mentioned design condition, a high performance reflective full color LCD is actually fabricated as a trial. This LCD was confirmed to have extremely high contrast and almost no color shift in wide viewing angle range. In addition, this LCD has as high brightness as a color photograph in wide viewing angle (0 to 50 degrees from normal direction) and higher contrast the color photograph.
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