Liquid crystal electro-optical devices

Claim 2

A liquid crystal electro-optical device comprising: a pair of opposed substrates spaced apart from each other by a predetermined constant distance; an electrode arrangement provided on the inner surfaces of said pair of substrates; and a chiral smectic liquid crystal layer interposed between said substrates; and wherein the arrangement is such that the molecular condition of said liquid crystal layer is controllable in accordance with the electric field applied thereto by means of said electrode arrangement and is capable of selectively adopting either of two optically anisotropic states between which transitions take place through an intermediate state in which the molecules form helices.

Claim 3

The device of claim 1 wherein said liquid crystal layer comprises a material which is such as to exhibit its smectic A phase at a temperature higher than that at which it exhibits its chiral smectic C phase.

Claim 4

The device of claim 1 or 2 wherein said liquid crystal layer comprises a material which is such that the temperature range in which its chiral smectic C phase appears is included by the range of -10°C and 70°C.

Claim 6

The device of claim 4 wherein said R, l and R* are as follows:

Claim 8

The device of claim 6 wherein said R, l, n, m and R* are as follows;

Claim 9

A liquid crystal electro-optical device comprising: a quantity of chiral smectic liquid crystal material; first and second means contiguous with said liquid crystal material for aligning the molecules of said liquid crystal material adjacent to said first and second means parallel to said first and second means, the distance between said first and second means being chosen so that the molecules of said liquid crystal material form helices in the absence of an electric field, said first and second means causing the molecules to assume one of a first and second stable orientation; means for applying an electric field to at least a portion of said liquid crystal material and for reversing the direction of said electric field, the strength of said electric field being sufficient to shift the molecules in said portion of said liquid crystal material from said first orientation to said second orientation upon application of said electric field in a direction reversed from the direction of said electric field previously applied; and means for processing light passing through said liquid crystal material so that light passing through portions of said liquid crystal having said first orientation can be distinguished from light passing through portions of said liquid crystal having said second orientation.

Claim 10

A liquid crystal electro-optical device comprising: a quantity of chiral smectic liquid crystal material; first and second means contiguous with said liquid crystal material for aligning the molecules of said liquid crystal material adjacent to said first and second means parallel to said first and second means, the distance between said first and second means being chosen so that the molecules of said liquid crystal material form helices in the absence of an electric field, said first and second means causing the molecules to assume one of a first and second stable orientation; means for applying an electric field to at least a portion of said liquid crystal material and for reversing the direction of said electric field, the strength of said electric field being sufficient to shift the molecules in said portion of said liquid crystal material from said first orientation to said second orientation upon application of said electric field in a direction reversed from the direction of said electric field previously applied; and means for processing light passing through said liquid crystal material so that light passing through portions of said liquid crystal having said first orientation can be distinguished from light passing through portions of said liquid crystal having said second orientation.

Claim 11

The device of claim 8 wherein said first and second means comprises plates having opposed polyimide and silicon oxide surfaces.

Claim 12

The device of claim 8 or 9 wherein said electric field applying means comprises first and second electrodes disposed adjacent to said first and second means, respectively, and means for applying a voltage across said first and second electrodes.

Claim 13

The device of claim 8 or 9 or 10 wherein said helices have a pitch and the distance between said first and second means is no less than five times said pitch.

Claim 14

The device of claim 8 or 9 or 10 or 11 wherein said orientation remains after said electric field is removed.

Claim 15

A bistable non-volatile ferroelectric liquid crystal electro-optical device wherein the liquid crystal material is sandwiched between the surfaces of opposed substrates which are spaced apart from each other by a distance which is a predetermined multiple of the helical pitch of the liquid crystal material molecular arrangement such that the liquid crystal material can be switched by an applied electric field between stable optically anisotropic states via an intermediate optically isotropic state.

Claim 16

A bistable non-volatile ferroelectric liquid crystal electro-optical device wherein the liquid crystal material is sandwiched between the surfaces of opposed substrates which are spaced apart from each other by a distance which is a predetermined multiple of the helical pitch of the liquid crystal material molecular arrangement such that the liquid crystal material can be switched by an applied electric field between stable optically anisotropic states via an intermediate optically isotropic state.