Abstract:
An orientation layer, optical retarder or similar liquid-crystal-polymer element having fixed alignment properties can be made using an irradiation method not requiring linearly polarised light. A material is exposed to unpolarised or circularly polarised oblique irradiation. Monomeric or pre-polymeric liquid crystal molecules applied to, or mixed with, the exposed material adopt a preferred alignment and, while so aligned, are cross-linked, to result in the said fixed alignment properties.
Abstract:
Ordered liquids, or mesophases, are aligned by forming a structure on a substrate surface using a planar process of formation, the surface structure having a predetermined pattern, and applying a mesophase to the surface to substantially orient the molecules of the mesophase in accordance with the predetermined pattern. A liquid crystal display device can be made in which, in a preferred embodiment, the liquid crystal (29) is confined between two substrates (20 and 21) having oppositely disposed surfaces on which selected patterns of surface structures have been formed. The surface structures can be grating structures (25 and 26) made of conductive material (23 and 24), such as metal, which structures act to align the liquid crystal in accordance with the selected patterns, to polarize light passing through the surface structures, and to provide electrical contacts so that an electric signal applied thereto can produce an electrical field in the region between the substrate surface structures.
Abstract:
A liquid crystal lens or beam steering device is made by programming alignment surfaces of the LC cell walls using a programming field to align the alignment surface molecules before fixing them. By setting the desired pre-tilt, the lens can operate in the absence of the control field, and power consumption by the control field can be reduced.
Abstract:
A liquid crystal cell has a wall able to impart both a preferred tilt and a preferred azimuthal alignment, not to mention a preferred alignment, to the liquid crystal molecules in use in the cell. The wall is made by exposing a material on it to oblique radiation which is circularly polarised or unpolarised.
Abstract:
A liquid crystal display cell comprises two cell walls spaced apart to enclose a layer of liquid crystal material. The cell walls carry electrode structures, e.g. arranged in rows and columns to give an x,y matrix of addressable elements or pixels. The liquid crystal material is aligned by a grating (grooved) structure on one or both cell walls. This grating structure is a bigrating with one symmetrical grating and an asymmetric grating which may be orthogonal to the symmetric grating. The grooves of the asymmetric grating varying their depth or asymmetry along the lengths to give a locally varying pretilt whose longer range average provides a pretilt in a preferred range, e.g. about 2-24 DEG .
Abstract:
A ferroelectric liquid crystal device comprises a layer of a ferroelectric liquid crystal material contained between two cell walls carrying electrode structures and a surface alignment treatment. The surface alignment is provided by a profiled surface, e.g. a grating, on at least one cell wall. The grating may be a monograting or a bigrating, with a symmetric or asymmetric profile. Such a profiling enables surface tilt and alignment anchoring energy to be independently arranged to suit liquid crystal material and device type to give a required molecular arrangement and low device defect. The grating may be provided by interferography, photolithography, embossing, ruling, or carrier layer transfer. Alignment directions on the cell walls may be parallel or non parallel. The surface tilt on both cell walls may be the same or different values. The cell walls may be relatively rigid, e.g. glass slides, or flexible e.g. thin plastic which may have its inner face embossed to provide one or both a grating and a set of spacer pillars.