Makoto Ishiguro

8.1: Quarter Wave Retardation Film for Improving Viewing Angle Properties in Time‐Sequential Stereoscopic 3D Liquid Crystal Displays

We investigated how to achieve desired optical properties of quarter wave retardation films QWFs that increase the viewing angle of time-sequential stereoscopic 3D liquid crystal displays LCDs, such as high luminance, low crosstalk, low color change, and low head-tilt-angle dependency. These display properties were strongly affected by the out-of plane retardation Rth of the QWF. We developed QWFs whose in-plane and out-of-plane retardation are independently controllable by adjustment of a polymerized discotic material layer and a triacetate cellulose film, and 3D-LCDs with high viewing angle properties were realized using these QWFs whose Rth was nearly zero.

New Approach to Enhance Contrast Ratio at Normal Incidence by Controlling the Retardation of Optical Compensation Film in Vertically Aligned Liquid Crystal Displays

We found that the light leakage at normal incidence of a vertically aligned liquid crystal display (VA-LCD) in black state is strongly affected by the polarization states of obliquely incident light. Experimental results were explained by a light scattering model of substrates on both sides of a liquid crystal layer. Applying this model, we found that the contrast ratio at normal incidence can be highly enhanced by controlling the retardation value of retardation films. This is a new, effective approach to enhancement of the contrast ratio in LCDs, different from the conventional approach of simply decreasing the depolarization of the scattering media.

Frequency Stabilization of a Semiconductor Laser under Direct Frequency Shift Keying Using the Saturated Absorption Signal

The oscillating frequency of a semiconductor laser was stabilised at the Rb-D 2 absorption line under direct frequency shift keying (FSK). The control system equipped with a peak-hold circuit provided the frequency stability of 10 -9 >σ(2, τ)>10 -12 at the averaging time 0.05 s<τ<40 s when the Doppler-limited absorption line was used as a frequency reference. This stability was better than that obtained by the traditional control system without the peak-hold circuit under direct FSK. Using the saturated absorption signal, the frequency stability was improved more than one order of magnitude in comparison with that obtained using the Doppler-limited absorption signal

55.1: Development of Low Haze VA Compensation TAC Film and Proposal of Compensation Film Arrangement for Improving CR in VA Panel

We developed a low-haze VA compensation TAC film for high contrast ratio VA-LCDs, by reducing micro anisotropic nonuniform structure inside the stretched TAC film. Moreover, we found that the arrangement of our low-haze VA compensation TAC film as a single compensator on the front side of VA-LCDs with color filter on TFT arrays realizes more than 10 % higher on-axis contrast ratio than that of conventional compensation films as double compensator.

55.2: Reduction of Light Leakage by Optical Compensation Film in VA‐LCDs

We investigated a light leakage at normal incidence of a vertically aligned liquid crystal display (VA-LCD) at black state. The light leakage was strongly affected by the polarization states of light obliquely incident on the cell. Experimental results were explained by a light scattering model of substrates on both sides of liquid crystal layer. Applying this result, we showed the light leakage can be highly reduced by controlling the retardation value of optical compensation film between the cell and a backlight unit.