Anisotropic shear viscosity in nematic liquid crystals: new optical measurement method
| Autor: | A.N. Voronov, Sergey V. Pasechnik, Valentin A. Tsvetkov, Vladimir G. Chigrinov, Dina V. Shmeliova |
|---|---|
| Rok vydání: | 2004 |
| Předmět: |
Liquid-crystal display
Materials science Bistability Condensed matter physics business.industry General Chemistry Condensed Matter Physics law.invention Condensed Matter::Soft Condensed Matter Physics::Fluid Dynamics Shear (sheet metal) Optics Liquid crystal law Electric field General Materials Science Anisotropy Shear flow business Intensity (heat transfer) |
| Zdroj: | Liquid Crystals. 31:585-592 |
| ISSN: | 1366-5855 0267-8292 |
| DOI: | 10.1080/02678290410001667371 |
| Popis: | We propose a new optical method and the experimental set-up for measuring the anisotropic shear viscosities of nematic liquid crystals (LCs). LC shear viscosities can be optimized to improve liquid crystal display (LCD) response times, e.g. in vertical aligned nematic (VAN) or bistable nematic displays (BND). In this case a strong back-flow effect essentially determines the LCD dynamic characteristics. A number of shear viscosity coefficients defines the LCD response time. The proposed method is based on the special type of a shear flow, namely, the decay flow, in the LC cell with suitably treated substrates instead of magnetic or electric field application. A linear regime of a quasi-stationary director motion induced by a pressure difference and a proper configuration of a LC cell produces decay flow conditions in the LC cell. We determine three principal shear viscosity coefficients by measuring relative time variations of the intensity of the light passed through LC cells. The shear viscosity coeffici... |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|