Electro-optical devices and methods for making them

Claim 1

An electro-optical device comprising an electrically responsive liquid crystal material contained between two walls which are bonded together in selected areas and have surface profiles which mutually cooperate to provide between them a multiplicity of microcells, at least one of the profiles having raised portions which provide the selected bonding areas and define the microcells, each cell holding a portion of the liquid crystal layer, the walls each having an electrically conductive layer positioned adjacent to at least a plurality of the microcells and separated from the conductive layer of the other wall by electrically insulating material, with means to connect the conductive layers to a source of electrical potential thereby to enable an electrical field to be applied across the adjacent microcells.

Claim 5

A device as claimed in any one of the preceding claims consisting essentially of two laminar sheets bonded together to form the liquid crystal-containing microcells, at least of one of the sheets comprising a substrate layer supporting an electrically conductive coating as a second layer, and having in contnct with the liquid crystal material a third layer of uneven thickness being profiled to define the microcells.

Claim 6

A method for manufacturing an opto-electrical device comprising bringing together two laminar sheets either side of a layer of electrically responsive liquid crystal material, the sheets each having an electrically conductive coating and surface profiles which mutually cooperate to provide between them a multiplicity of microcells, each holding a portion of the liquid crystal layer, bonding together the two profiled surfaces in areas between and defining the microcells while maintaining or providing a layer of electrical insulation between the electrically conductive coatings in those bonded areas, at least some of the electrically conductive coatings being adjacent to at least some of the microcells thus formed, and exposing portions of the two conductive coatings to enable them to be connected to a source of electrical potential for providing an electrical field across the microcells formed therebetween.

Claim 7

A method for manufacturing an opto-electrical device comprising bringing together two laminar sheets either side of a layer of electrically responsive liquid crystal material, the sheets each having an electrically conductive coating and surface profiles which mutually cooperate to provide between them a multiplicity of microcells, each holding a portion of the liquid crystal layer, bonding together the two profiled surfaces in areas between and defining the microcells while maintaining or providing a layer of electrical insulation between the electrically conductive coatings in those bonded areas, at least some of the electrically conductive coatings being adjacent to at least some of the microcells thus formed, and exposing portions of the two conductive coatings to enable them to be connected to a source of electrical potential for providing an electrical field across the microcells formed therebetween.

Claim 10

A method as claimed in any one of claims 5 to 7, in which the microcell-defining surface structure is formed by photolithography.

Claim 11

A method as claimed in any one of claims 5 to 8 which comprises in situ forming of the microcell-­defining surface structure in a surface of one of the sheets prior to bonding together of the two sheets.

Claim 12

A method as claimed in any one of claims 5 to 8 which comprises preforming a net-like lattice structure and bonding this to one of the sheets thereby to provide the microcell-defining surface structure of that sheet.

Claim 13

A method as claimed in any one of claims 5-10, in which the two sheets are bonded together by welding the two microcell-defining surfaces where their surface profiles bring them into contact with each other.