Yoshiharu Ooi

Methods of Achieving Compatibility between High-Density Disk and Digital Versatile Disk Using a Bi-aspherical Singlet and a Wavefront Compensation Element

We have suggested methods to achieve read/write compatibility for a high-density (HD) disk of 0.1 mm substrate thickness and digital versatile disk of 0.6 mm substrate thickness by simply adding an optical element. We have confirmed that the polarized holographic optical element (HOE) and polarized phase compensator (PPC) are strong candidates for achieving compatibility.

Morphology and ordering control in LCPC

A phase separation under an applied electric field (PSUF treatment) in LCPC relaxes the energetic stress for dynamic operation of its device. Both higher dynamic response time and less hysteresis in dark gray scales which are significant issues in LCPC are achieved, since its treatment can control the interface between liquid crystal and matrix polymer without the damage to scattering in off state and contrast ratio. It is based on the morphological characteristic which is caused by the first step: a segregation of liquid crystal and ordering process of the liquid crystal under an applied field, and the second step: polymer/pre-polymer precipitation to maintain the early ordering of segregated liquid crystal. The essential structure of LCPC caused by the characteristic phase separation process, is characterized with confocal fluorescence microcopy, which also supports its process mechanism.

Display-Special Contribution from IDW '98. Reflective-type polymer dispersed LC-mode Projection Display.

A new compact projection display has been developed using light valves based on a 2-inch diagonal low-temperature poly-Si TFT reflective XGA array and polymer dispersed LC-mode, 120-W ultrahigh-pressure short-arc lamp (UHP lamp), and simple optical components. Luminous flux of 1400 ANSI-lm, contrast ratio of 85, and the illuminance homogeneity of 90% were achieved. Simulation by basic optical theory in concentrators and experiments with a simplified reflective-type polymer dispersed LC-mode light valve indicates that the performance could be improved in future up to a luminous flux of 1600 ANSI-lm with contrast ratio of more than 150.