Ryuichiro Isobe

34.3: Quasi- and Analog-Full-Color Displaying Methods with High Light Efficiency in Super-High-Resolution LCDs

A new coloring method of LCD (liquid crystal display) using the hybrid structure of CF (color filter) method and the interference coloration of ECB (electrically controlled birefringence) effect is presented. One unit pixel is divided into at least two sub-pixels, and the one sub-pixel is equipped with a green CF and the other one a magenta CF. As for the green coloration of the highest luminosity property, a green CF is used in order to display the analogue gray scale. The interference coloration of ECB effect with a magenta CF is used for red and blue binary coloration as well as analogue gray scale of the magenta color. Monochrome gray scale can be realized by the additive color mixing of green and magenta sub-pixels. The VA (vertical alignment) mode is adopted for suppressing the temperature dependence of the optical retardation. We can achieve much better light efficiency than that of the conventional color LCDs with both an RGB-CF and a polarizer. This mode has the features of quasi-full color and wide color space for red and blue color by the subtractive color mixing effect between interference coloration and magenta CF. Furthermore, the present LCD can be fabricated without changing the conventional LCD process and materials. We also present the analog-full-color method, which can be realized by using small additive sub-pixels of red and blue colors.

Dot Inversion Spontaneous Polarization Structure in the Half-V-shaped Switching Ferroelectric Liquid Crystal Mode

The half-V shaped switching ferroelectric liquid crystal mode (half-V FLC mode) can easily yield excellent moving pictures based on the nonholding display by simple AC driving. However, the AC driving in the entire area of the liquid crystal display (LCD) panel (i.e. the field-inversion drive method) raises a concern of the cross talk problem in large-size LCD panels. In this paper, we propose a novel alignment method that is controlled to yield alternating layer directions between neighboring pixels. Such layer structures correspond to the structure of dot inversion spontaneous polarization, and a nonholding display can be realized by the dot-inversion drive method. By this method, we can simultaneously obtain a cross-talk-free display, excellent moving pictures and wider viewing angle. The contrast ratio is expected to be improved by further liquid crystal development and/or the multi-domain process technology.

Analysis of the Hysteresis Phenomenon in the Intrinsic Half-V-Shaped Switching Ferroelectric Liquid Crystal Mode

The intrinsic half-V-shaped switching ferroelectric liquid crystal mode (iHV-FLC mode) is known to be able to easily yield excellent moving pictures without blurring, based on the nonholding display by simple AC driving in the ideal condition. However, we have sometimes observed the blurred moving pictures even in the iHV-FLC mode with very short response time. We have conducted the detailed measurement of the electrooptical response. The protracted hysteresis phenomenon could be observed in some cells. This phenomenon had a strong relationship with the internal ionic impurity density. The 1st frame hysteresis phenomenon could be observed even in the purest cells. It is considered to be caused by the c-director position at zero field and its driving scheme.