Takanobu Nakagawa

8.4: Transflective LCD with Low Driving Voltage and Wide Viewing Angle

A 3.8-inch transflective thin-film-transistor liquid crystal display TFT-LCD with a wide viewing angle that enables operation over a small driving voltage range between 1.5V and 4.0V has been developed. This is achieved by optimizing the retardation of the LC layer and the parameters of the compensation film, which minimizes a viewing angle dependence of the total retardation of the LC layer and the compensation films.

Development of Wide-Viewing-Angle TFT-LCDs using halftone gray-scale method

We have developed wide-viewing-angle TFT-LCDs using the halftone gray scale (HTGS) method. Compared with conventional TN-LCDs, the viewing angle of HTGS TFT-LCDs is twice as wide in the up-down direction and has also greatly improved in the diagonal direction. The gray-scale display response time of HTGS TFT-LCDs is also shorter by one-half compared with conventional TN-LCDs. We have studied the application of HTGS TFT-LCDs to passenger cabin entertainment use. In contrast to consumer use, environmental durability characteristics are required; however, the developed HTGS TFT-LCDs meet all of the requirements and have been practically used. This paper presents the principles of HTGS, the pixel design, the device structure, the electro-optical characteristics, and the application to passenger cabin entertainment.