Yuet-Wing Li
Hong Kong University of Science and Technology
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Publication
Featured researches published by Yuet-Wing Li.
SID Symposium Digest of Technical Papers | 2005
Fion Sze Yan Yeung; Yuet-Wing Li; Hoi Sing Kwok
A bistable liquid crystal display based on the bend and splay configurations has been demonstrated using dual frequency liquid crystal. Unlike the previous three-electrode version, only two regular electrodes are needed in the present case. We also propose and demonstrate a convenient multiplex driving scheme for a BBS matrix display.
Applied Physics Letters | 2009
Yuet-Wing Li; Hoi Sing Kwok
Bistability of twisted-bend and twisted configuration is found. It is based on the elastic and topological inequivalency of director orientation. Multiple states of minimum local energy exist, with appropriate boundary conditions. The effects of elastic constants, d/P ratio and pretilt angle are also investigated. Fast electrical switching time <500u2002μs and high average contrast of 45:1 are obtained experimentally.
Journal of The Society for Information Display | 2008
Yuet-Wing Li; Li Tan; Hoi Sing Kwok
— Passive-matrix-driven field-sequential-color (FSC) displays were successfully fabricated. It makes use of a new multiplex driving scheme that does not depend on voltage averaging. Instead, a transient response of the liquid crystal is employed. An addressing and response time of less than 70 μsec and 2.0 msec, respectively, are used. Scanning time compensation is also introduced to improve the brightness uniformity of the display.
Molecular Crystals and Liquid Crystals | 2009
Hoi Sing Kwok; Yuet-Wing Li; Fion Sze Yan Yeung
The alignment of liquid crystal by nano-structured surfaces is investigated. Two methods of preparing the nano-structured inhomogeneous surfaces will be examined. It is shown that this type of surface can give excellent alignment properties. Reliable pretilt angles of any value between 0 and 9° can be obtained. Novel multi-domain structures can also be made in conjunction with photoalignment. These nano-structured alignment layers are very useful for a variety of display applications.
Digest of Technical Papers - SID International Symposium | 2007
Yuet-Wing Li; Li Tan; Fion Sze Yan Yeung; Hoi Sing Kwok
fast liquid crystal display mode is demonstrated. This liquid crystal mode is based on a stressed splay twist deformation and can be driven in passive matrix or active matrix manners. This new display mode can be used to achieve full color display effect, in conjunction with a pulsed red-green-blue backlight unit.
SID Symposium Digest of Technical Papers | 2009
Chung Yung Lee; Yuet-Wing Li; Hoi Sing Kwok
A new alignment layer is developed. This alignment layer is capable of generating arbitrary pretilt and azimuth angles for the liquid crystal. It is based on stacking both photo-aligned polymer and rubbed polyimide together. The alignment produced is robust. Moreover, the processing window is also maximized.
SID Symposium Digest of Technical Papers | 2010
Chung Yung Lee; Man Chun Tseng; Yuet-Wing Li; Hoi Sing Kwok
A new discontinuous alignment layer is developed. The formation of such discontinuous structure is created by self-organized dewetting. Different dewetting mechanisms have been investigated. Such a discontinuous alignment layer can be fabricated on top of a continuous alignment layer. This heterogeneous surface for liquid crystal alignment can be used to produce arbitrary pretilt angles for the liquid crystal cell. Experiments using photo-aligned polymer have been done to verify the dewetting theory. The alignment layers thus produced are proved to be robust. Moreover, the dewetting step is a fully controllable process and is compatible with existing manufacturing techniques.
SID Symposium Digest of Technical Papers | 2007
Fion Sze Yan Yeung; Yuet-Wing Li; Li Tan; Jacob Y L Ho; Kuen‐Kuen Li; Wai-Shan Cheung; Hoi Sing Kwok
A field sequential color (FSC) LCD is made using the no-bias bend (NBB) mode. This NBB mode is made possible using a nano-structured alignment layer which is capable of producing any pretilt angles. This NBB pi-cell has a total response time less than 1.3ms which is needed for FSC.
SID Symposium Digest of Technical Papers | 2006
Hoi Sing Kwok; Fion Sze Yan Yeung; Yuet-Wing Li
Several new nematic bistable liquid crystal displays based on a new alignment surface have been demonstrated. Nano-textured alignment surfaces enable the generation of arbitrary pretilt angles and arbitrary anchoring energy. Based on such surfaces, three types of bistable devices have been developed. They are bistable bend-splay, bistable twist-twist and bistable bend-twisted displays.
SID Symposium Digest of Technical Papers | 2008
Shuyun Zhao; Zhiguo Meng; Yuet-Wing Li; Man Wong; Hoi Sing Kwok
Color-sequential liquid crystal display (CS-LCD) can be realized without color filter but using a field sequential LED backlight, which enables a high efficiency of backlight and low power consumption. In this paper, the fast addressing active matrix for CS-LCD is designed and fabricated with the technology of metal induced continuous zonal domain (CZD) polycrystalline silicon thin film transistors (TFTs). This panel provides fast addressing characteristics and large aperture ratio. Assembled with fast liquid crystal technology, high color purity and clear moving image can be obtained.