International Standard Electric Corporation

Itt Industries, Inc.

Joseph H Morrissy

William A Crossland

David Coates

Barbara Needham

Derek H Mash

In a liquid crystal cell parallel homogeneous alignment of the liquid crystal molecules is provided by rubbing a silica or silica containing film produced by firing a silica containing organic coating applied in liquid form. The alignment provided by this process can withstand firing temperatures in the range 450.degree. to 500.degree. C. normally employed for making fused glass frit perimeter seals. By incorporating titania into the film the refractive index can be matched with that of the underlying electrodes and so render them substantially invisible.

Aligning liquid crystal layers

A liquid crystal display cell provides more than two contrasting colors that operates in a storage mode which has a positive dielectric anisotropy smectic liquid layer between electroded plates treated to produce parallel homogeneous alignment with a very large tilt angle. The tilt angle can be progressively increased by increasing the strength of an applied alternating potential thereby producing Newtonian colors when viewed through crossed polarizers. When pseudo-homogeneous zero tilt alignment is provided, a pleochroic dye may be mixed with the smectic to provide a color when the layer is in the pseudo-homogeneous alignment state. An applied electric field converts this to homeotropic alignment. When a negative dielectric anisotropy smectic liquid layer is sandwiched between electroded plates treated to induce homeotropic alignment, application of an electric field turns the display from clear (black between crossed polarizers) to milky as the alignment changes from homeotropic towards homogeneous (metastable) degenerating to focal-conic.

Liquid crystal display incorporating positive and negative smectic

A nematic liquid crystal cell operating in a field effect scattering mode employs a surfactant to provide homogeneous random alignment of the nematic director. Field effect scattering mode operation improves over dynamic scattering mode operation by using an electric field to switch between homeotropic and homogeneous random alignment.

Liquid crystal cell

A method for preparing and operating dynamic scattering liquid crystal display cells having internal electrodes and containing a smectic liquid having positive dielectric anisotropy and incorporating a homeotrophic alignment inducing medium for the smectic liquid filling. The cell can be switched off to make the transition from dynamic scattering to static scattering for providing indefinite storage properties.

Method for preparing and operating a smectic liquid crystal display cell

A method of controlling the spacing between the panels in large area liquid crystal cells consisting of the application of an array of spacer dots on one panel and an array of tie dots on the other panel. Upon firing the panels, the spacer dots remain rigid to define the spacing whereas the tie dots soften and deform.

Method of forming large liquid crystal cells

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.

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Dunmow, United Kingdom

Joseph H Morrissy