Liquid crystal rotator
First Claim
1. A liquid crystal cell including a layer of cholesteric material having a pitch longer than the quotient of the wavelength of light divided by the birefringence, but not longer than four times the layer thickness, which layer is sandwiched between two transparent electroded plates one having surface treatment providing, in the absence of the electric field across the layer, homeotropic alignment of the liquid crystal molecules adjacent said one plate, while other plate has a surface treatment providing, in the absence of an electric field across the layer, homogeneous parallel alignment of the liquid crystal molecules adjacent said other plate.
1 Assignment
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Accused Products
Abstract
A cholesteric filled liquid crystal cell has one surface homeotropically aligned and the opposite surface homogeneous parallel aligned. Plane polarized light incident upon the homogeneous parallel aligned surface with its polarization plane parallel with or orthogonal to the alignment direction has its plane of polarisation rotated by an amount controllable by the application of an electric potential across the cell. This forms the active element of a simulated rotating pointer meter display having no moving parts and only a single pair of electrical inputs.
51 Citations
8 Claims
- 1. A liquid crystal cell including a layer of cholesteric material having a pitch longer than the quotient of the wavelength of light divided by the birefringence, but not longer than four times the layer thickness, which layer is sandwiched between two transparent electroded plates one having surface treatment providing, in the absence of the electric field across the layer, homeotropic alignment of the liquid crystal molecules adjacent said one plate, while other plate has a surface treatment providing, in the absence of an electric field across the layer, homogeneous parallel alignment of the liquid crystal molecules adjacent said other plate.
Specification