Bistable Twisted Nematic Liquid Crystal Display Based on Dual Frequency Operation雙頻率雙穩態扭曲液晶顯示器
There are many applications for the Liquid crystal displays (LCD) that are bistable under zero voltage bias conditions. For examples, bistable cholesteric LCD; bistable ferroelectric LCD; bistable twisted nematic LCD where the two stable twist states differ by 360 degrees in twist angle; bistable twisted nematic LCD where the two stable twist states differ by 180 degrees in twist angle and zenithal bistable display which is based also on nematic liquid crystals.
The present invention is related to the method of construction and driving scheme of the pi-BTN bistable twisted nematic LCD. The special combination of the alignment glass layers and liquid crystals enables the bistability. The novel driving scheme also enables this bistable display to be switched easily. In particular, the cell gap can be much larger than the 2µm required for the Dozov pi-BTN. As a result, the driving scheme is much simpler than the conventional one. The liquid layer is of the dual frequency type. It changes its dielectric anisotropy according to the frequency of AC signal of sinusoidal or pulsed type of the driving voltage. So that the optical properties are optimized.
The invention can be applied in asymmetric anchoring and dual frequency liquid crystals.
1. Simpler driving scheme
2. Bistability under zero voltage bias condition is achieved
- Asymmetric anchoring
- Dual frequency liquid crystals
Patent Number: US7551252B2
Application Number: US2006604072A
Inventor: Kwok, Hoi-Sing | Yeung, Fion Sze Yan | Li, Yuet Wing
Priority Date: 29 Nov 2005
Priority Number: US7551252B2
Application Date: 24 Nov 2006
Publication Date: 23 Jun 2009
IPC Current: G02F00011337
US Class: 349126 | 349160 | 349179
Assignee Applicant: The Hong Kong University of Science & Technology
Title: Bistable twisted nematic liquid crystal display based on dual frequency operation
Usefulness: Bistable twisted nematic liquid crystal display based on dual frequency operation
Novelty: Bistable twisted nematic liquid crystal display, has alignment layer imparting preferred direction for liquid crystal molecules and possessing different azimuthal and polar anchoring energies when used to align crystal layer
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24 Nov 2006
US 11/604072
US 7551252
TTC.PA.279S
香港
