Liquid crystal device for generation and fast switching of high contrast images
First Claim
1. A liquid crystal device comprising two substrates confining there between an antiferroelectric liquid crystal (AFLC) material having a molecular tilt angle in the range of 40°
- ≦
θ
≦
50°
, wherein the AFLC material exhibits a field-induced antiferroelectric to ferroelectric transition (AF-to-F transition) of second order during application of an electric field.
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Abstract
An electro-optic device including a liquid crystal material is disclosed, comprising antiferroelectric liquid crystals with large molecular tilt θ of about 45° degrees, disposed between two flat glass or polymer substrates. The liquid crystal molecules are preferably oriented parallel to the substrates (so-called HAF texture). The device is e.g. placed between two crossed polarizers so that in field-off conditions the impinging light is not passing through the device due to the isotropic optical properties of the antiferreoelectric liquid crystal aligned in HAF texture. An applied electric field induces a continuous transition of the optically isotropic antiferreoelectric (AF) state to ferroelectric (F) one which is birefringent enabling the transmission of light. The field-induced continuous switching between the optically isotropic antiferreoelectric state and the birefringent ferroelectric state enables the generation and fast switching of high contrast as well as generation of grey scale levels.
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Citations
30 Claims
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1. A liquid crystal device comprising two substrates confining there between an antiferroelectric liquid crystal (AFLC) material having a molecular tilt angle in the range of 40°
- ≦
θ
≦
50°
, wherein the AFLC material exhibits a field-induced antiferroelectric to ferroelectric transition (AF-to-F transition) of second order during application of an electric field. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 29, 30)
- ≦
- 21. A liquid crystal device comprising a sandwich cell with a pair of substrates forming a cavity there between and a liquid crystal bulk layer arranged in between said substrates in said cavity, wherein at least one of the substrates is transparent, and wherein the liquid crystal bulk is antiferroelectric liquid crystal (AFLC) material with high molecular tilt, exhibiting a continuous (second order) field-induced antiferroelectric to ferroelectric transition (AF-F) transition.
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27. An electro-optic device including:
- a liquid crystal material comprising antiferroelectric liquid crystals with large molecular tilt θ
of about 45°
degrees;
tow flat substrates, wherein the liquid crystal material is disposed between the substrates, wherein the substrates have electrode pattern on their inner surfaces facing the liquid crystal wherein the liquid crystal molecules are oriented parallel to the substrates in a HAF texture;
tow crossed polarizers, arranged so that in a field off condition impinging light is not passing through the device due to the isotropic optical properties of the antiferroelectric liquid crystal aligned in HAF texture, whereas an applied electric field induces a second order transition of the optically isotropic antiferroelectric (AF) state to a ferroelectric (F) state which is birefringent enabling the transmission of light wherein the field-induced continuous switching between the optically isotropic antiferroelectric state and the birefringent ferroelectric state enables the generation and fast switching of high contrast as well as generation of grey scale levels. - View Dependent Claims (28)
- a liquid crystal material comprising antiferroelectric liquid crystals with large molecular tilt θ
Specification