Controlling the alignment of liquid crystals by nanoparticle-doped and UV-treated polyimide alignment films

We have developed two approaches for controlling the pretilt angles of liquid crystal molecules by using conventional polyimide (PI) alignment materials either doping homogeneous PIs with Polyhedral Oligomeric Silsequioxanes (POSS) nanoparticles or treating homeotropic PIs with ultraviolet light. These techniques are very simple and are compatible with current methods familiar in the LCD industry. The characteristics of modified PI alignment films and their applications for photonic devices are demonstrated in this paper.

[1]  Kunihiro Ichimura.  Photoalignment of Liquid‐Crystal Systems , 2000 .

[2]  A. Fuh,et al.  Controlling pre-tilt angles of liquid crystal using mixed polyimide alignment layer. , 2008, Optics express.

[3]  M. Nishikawa.  Design of polyimides for liquid crystal alignment films , 2000 .

[4]  Chi Woo Kim,et al.  A single‐cell‐gap transflective LCD using active‐level‐shift technology , 2010 .

[5]  Shie-Chang Jeng,et al.  Nanoparticles-induced vertical alignment in liquid crystal cell , 2007 .

[6]  O. Lavrentovich,et al.  Nematic Polar Anchoring Strength Measured by Electric Field Techniques , 1999 .

[7]  P. Sheng,et al.  Variable liquid crystal pretilt angles by nanostructured surfaces , 2006 .

[8]  H. Kwok,et al.  Bistable Bend-splay Liquid Crystal Display , 2004 .

[9]  S. Jeng,et al.  Nanoparticle-doped polyimide for controlling the pretilt angle of liquid crystals devices. , 2010, Optics express.

[10]  Matthew E. Sousa,et al.  Continuous control of liquid crystal pretilt angle from homeotropic to planar , 2007 .

[11]  H. Kwok,et al.  Simultaneous Determination of Large Pretilt Angles and Cell Gap in Liquid Crystal Displays , 2008, Journal of Display Technology.

[12]  Tien-Jung Chen,et al.  Pretilt angle control for single-cell-gap transflective liquid crystal cells , 2008 .

[13]  Hoi Sing Kwok,et al.  Photoalignment of Liquid Crystalline Materials: Physics and Applications , 2008 .

[14]  Shie-Chang Jeng,et al.  Tunable pretilt angles based on nanoparticles-doped planar liquid-crystal cells. , 2009, Optics letters.

[15]  Yong Bae Kim,et al.  Surface free energy and pretilt angle on rubbed polyimide surfaces , 1999 .

[16]  Jae-Min Oh,et al.  Effect of side chain structure of polyimides on a pretilt angle of liquid crystal cells , 2006 .

[17]  Y. Koike,et al.  Inclined Homeotropic Alignment by Irradiation of Unpolarized UV Light , 1997 .

[18]  Soo In Jo,et al.  Control of liquid crystal pretilt angle by anchoring competition of the stacked alignment layers , 2009 .

[19]  E. Gulari,et al.  Ultraviolet light induced changes in polyimide liquid-crystal alignment films , 1996 .

[20]  L. Komitov.  Tuning the alignment of liquid crystals by means of nano‐structured surfaces (Invited Paper) , 2008 .

[21]  Hoi Sing Kwok,et al.  Fast-response no-bias-bend liquid crystal displays using nanostructured surfaces , 2006 .

[22]  Shigeaki Mizushima,et al.  41.1: Distinguished Paper: The World's First Photo Alignment LCD Technology Applied to Generation Ten Factory , 2010 .

[23]  Jung-Ki Park,et al.  Control of liquid crystal pretilt angles by using organic/inorganic hybrid interpenetrating networks. , 2009, Optics express.

[24]  Shie-Chang Jeng,et al.  Electrically switchable liquid crystal Fresnel lens using UV-modified alignment film. , 2010, Optics express.

[25]  C. Kuo,et al.  Characteristics of nanoparticle-doped homeotropic liquid crystal devices , 2009 .

[26]  C. Durning,et al.  A mechanistic picture of the effects of rubbing on polyimide surfaces and liquid crystal pretilt angles , 1998 .

[27]  Tatsuo Uchida,et al.  Liquid Crystal Orientation on the Surface of Obliquely-Evaporated Silicon Monoxide with Homeotropic Surface Treatment , 1980 .

[28]  John L. Janning.  Thin film surface orientation for liquid crystals , 1972 .