High-definition vertically aligned liquid crystal microdisplays using a circularly polarized light

A high-definition vertically aligned liquid crystal (LC) microdisplay exhibits a excellent contrast ratio, but its fringing field effect splits the bright state unevenly and leads to a very slow response time. By utilizing a circularly polarized light instead of conventional linearly polarized light, we have overcome the long-standing problems of poor sharpness, low brightness, and slow response time. Confirming computer simulations agree with the experimental results well. This approach can be applied to both reflective and transmissive LC microdisplays

Eliminating Fringing Field Effects Of Vertically Aligned Liquid-Crystal-On-Silicon By Using Circularly Polarized Light

The undesirable fringing field effects of the vertically aligned liquid-crystal-on-silicon (LCOS) are eliminated by using a circularly polarized light. Both simulations and confirmed experimental results indicate that the sharpness and the brightness of the displaying images are significantly improved. Furthermore, the dynamic transition time from the dark-bright-dark state to the all-bright state is less than 10 ms, which has successfully overcome the image blurring effect. © 2005 SID

Diffraction Effect On High-Resolution Liquid-Crystal-On-Silicon Devices

We extend the beam propagation method to calculate light propagation in reflective liquid crystal displays. The effect of diffraction on the optical performance of high-resolution liquid-crystal-on-silicon devices is investigated. The light efficiencies are simulated with respect to the pixel pitch for the vertically aligned and finger-on-plane modes. Computer simulation results indicate that the effect of diffraction on these devices is significant. © 2005 The Japan Society of Applied Physics

Fringing-Field Effects On High-Resolution Liquid Crystal Microdisplays

Fringing-field effects on high-resolution liquid crystal microdisplay devices, including the reflection-type liquid-crystal-on-silicon (LCOS) and transmission-type poly-silicon thin-film-transistor liquid crystal displays are simulated by the beam propagation method. The electro-optic performances of six commonly used liquid crystal modes are analyzed by the two-dimensional optical simulator. The vertically aligned (VA) cell exhibits the highest contrast ratio, but its fringing-field effect is severe. A circularly polarized light illuminated LCOS device is presented to eliminate the fringing-field effect of the VA cell. Both simulated and confirming experimental results show that the long-standing problems of poor sharpness, low brightness, and slow transition time of the VA cell can be overcome by using a circularly polarized light. © 2005 IEEE

Fringing Field Effect Of The Liquid-Crystal-On-Silicon Devices

The fringing field has an important effect on the contrast ratio of liquid-crystal-on-silicon (LCOS) display devices. Computer simulation results of five commonly employed LC operating modes are compared: mixed-mode twisted nematic (MTN) cell, 45 twisted nematic cell, vertical alignment (VA) cell, film-compensated homogeneous cell, and fringe-field switching cell. The slope of the pixel electrodes is found to make an important contribution to the brightness and contrast ratio of each mode. Simulation results indicate that the VA mode has the best contrast ratio when all the pixels are on and off. However, the MTN cell shows the smallest fringing field effect when alternating pixels are switched on and off

Enlarging the Eyebox of Maxwellian Displays with a Customized Liquid Crystal Dammann Grating

The Maxwellian view offers a promising approach to overcome the vergence-accommodation conflict in near-eye displays, however, its pinhole-like imaging naturally limits the eyebox size. Here, a liquid crystal polymer-based Dammann grating with evenly distributed energy among different diffraction orders is developed to enlarge the eyebox of Maxwellian view displays via pupil replication. In the experiment, a 3-by-3 Dammann grating is designed and fabricated, which exhibits good efficiency and high brightness uniformity. We further construct a proof-of-concept Maxwellian view display breadboard by inserting the Dammann grating into the optical system. The prototype successfully demonstrates the enlarged eyebox and full-color operation. Our work provides a promising route of eyebox expansion in Maxwellian view displays while maintaining full-color operation, simple system configuration, compactness, and lightweight

Tunable-Focus Cylindrical Liquid Crystal Lenses

Tunable-focus cylindrical liquid crystal lenses of four different electrode configurations are analyzed. Simulation results show that the proposed devices can have different focal lengths even if they have the same aperture size. A good agreement between experiment and simulation results is obtained. The imaging property of one of the cylindrical liquid crystal lenses is also demonstrated. © 2005 The Japan Society of Applied Physics