Browsing by Author "Chen, Tai-An"

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Broadband cholesteric liquid crystal devices with poly(N-vinyl carbazole) microstructures
(2015-01-02)
Hu, Jia-Wei
;
Chen, Tai-An
;
Jeng, Shie-Chang
;
光電系統研究所
;
影像與生醫光電研究所
The particular thermally induced phase separation (TIPS) method was developed by using poly(N-vinyl carbazole) (PVK) dissolved in liquid crystal (LC) layer recently. Permanent scattering is produced via the particular TIPS due to the formation of poly-domain LCs. In this work, we applied the particular TIPS to a conventional cholesteric LC (CLC) device. A broadband CLC device with a poly-domain structure was demonstrated by using the particular TIPS of CLC and PVK. The CLC device fabricated by two indium tin oxide glass substrates coated with PVK films generated the rough PVK layers and microstructures when the device was cooled from a temperature higher than the clear point of CLCs. The produced poly-domain planar texture of CLCs still preserved the bistability. A high cooling rate and PVK concentration both increased the reflection bandwidth of the CLC devices.
Controlling the alignment of liquid crystals by nanoparticle-doped and UV-treated polyimide alignment films
(2012)
Jeng, Shie-Chang
;
Hwang, Su-June
;
Chen, Tai-An
;
Liu, Han-Shiang
;
Chen, Mu-Zhe
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.