Liquid crystal cells – elements and systems – Particular excitation of liquid crystal – Electrical excitation of liquid crystal
Patent
1997-02-06
1999-03-02
Sikes, William L.
Liquid crystal cells, elements and systems
Particular excitation of liquid crystal
Electrical excitation of liquid crystal
349170, 349 98, G02F 1133, G02F 11335, C09K 1902
Patent
active
058778268
ABSTRACT:
A liquid crystal shutter and a drive waveform for controlling the same is presented by this invention. The liquid crystal shutter includes two distinct layers of liquid crystal material where one layer has a right hand twist sense and the other layer has a left hand twist sense. An electric field is selectively applied to the layers of liquid crystal material which have dual frequency properties. Accordingly, when a low frequency is applied to the liquid crystal materials they exhibit a positive dielectric anisotropy and a homeotropic texture which is substantially transparent. When a high frequency electric field is applied to the liquid crystal materials they exhibit a negative dielectric anisotropy and a planar texture which is substantially reflective. The liquid crystal material may be selected to selectively reflect predetermined spectrums of light. By alternatingly applying low and high frequencies to the liquid crystal shutter, the transition time between the transparent and reflective states is minimized.
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Xu Ming
Yang Deng-Ke
Chowdhury Tarifur R.
Kent State University
Sikes William L.
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