Addressing method for a multiplexable, bistable liquid crystal display

Claim 3

A method according to claim 1, further comprising the steps of: dividing the display elements into at least one writing region in which information being displayed by said display elements can be changed and into at least one holding region in which no changes in the optical states of the display elements can be made, and simultaneously applying said writing voltage to all the display elements in said at least one writing region.

Claim 5

A method according to claim 3, wherein the writing voltage is at least one and one-half times as large as the first limiting voltage.

Claim 7

A method according to claim 5, wherein the writing voltage is 0 V.

Claim 11

A multiplexable, bistable liquid crystal display comprising: parallel substrate plates having inner surface defining respective parallel planes which, with a border seal, form a cell; a guest-host liquid crystal filled in the cell, said crystal comprising a nematic liquid crystal with positive dielectric anistropy, pleochroic dyes and a chiral additive; electrode layers and orienting layers on the inner surfaces of the substrate plates, said electrode layers, orienting layers and liquid crystal filled in the cell defining a plurality of bistable display elements each of which can adopt a first optical state and a second optical state; wherein at least one of the orienting layers induces a pretilt angle (a) on liquid crystal molecules adjacent the at least one of the orienting layers, said pretilt angle (a) being larger than 5° measured from the plane of the substrate; said liquid crystal layer having a thickness (d) smaller than 10 m; said pretilt angle (a) being smaller than 40°; said guest-host liquid crystal having a layer thickness (d) and a pitch length (p) defining a ratio (d/p) greater than or equal to 0.5 and less than 1.75, such that a total twist of the liquid crystal molecules in the cell lies between 180° and 630°; spacer particles distributed throughout said cell; and means for addressing said plural display elements, comprising, means for applying a writing voltage for a predetermined time period to at least one of said display elements regardless of the optical state of said at least one of said elements, means for applying a first driving voltage to said at least one of said elements after applying said writing voltage thereto when said at least one of said elements is to be put into or remain in the first optical state, said first driving voltage being greater than a first limiting voltage above which the second optical state spontaneously transforms into the first optical state, and means for applying a second driving voltage to said at least one of said elements after applying said writing voltage thereto when said at least one of said elements is to be put in said second optical state, said second driving voltage being smaller than a second limiting voltage below which the first optical state spontaneously transforms into said second optical state, said second limiting voltage being less than or equal to said first limiting voltage; wherein said writing voltage is selected to have a value outside a voltage range extending from said first driving voltage to said second driving voltage.

Claim 12

A multiplexable, bistable liquid crystal display comprising: parallel substrate plates having inner surface defining respective parallel planes which, with a border seal, form a cell; a guest-host liquid crystal filled in the cell, said crystal comprising a nematic liquid crystal with positive dielectric anistropy, pleochroic dyes and a chiral additive; electrode layers and orienting layers on the inner surfaces of the substrate plates, said electrode layers, orienting layers and liquid crystal filled in the cell defining a plurality of bistable display elements each of which can adopt a first optical state and a second optical state; wherein at least one of the orienting layers induces a pretilt angle (a) on liquid crystal molecules adjacent the at least one of the orienting layers, said pretilt angle (a) being larger than 5° measured from the plane of the substrate; said liquid crystal layer having a thickness (d) smaller than 10 m; said pretilt angle (a) being smaller than 40°; said guest-host liquid crystal having a layer thickness (d) and a pitch length (p) defining a ratio (d/p) greater than or equal to 0.5 and less than 1.75, such that a total twist of the liquid crystal molecules in the cell lies between 180° and 630°; spacer particles distributed throughout said cell; and means for addressing said plural display elements, comprising, means for applying a writing voltage for a predetermined time period to at least one of said display elements regardless of the optical state of said at least one of said elements, means for applying a first driving voltage to said at least one of said elements after applying said writing voltage thereto when said at least one of said elements is to be put into or remain in the first optical state, said first driving voltage being greater than a first limiting voltage above which the second optical state spontaneously transforms into the first optical state, and means for applying a second driving voltage to said at least one of said elements after applying said writing voltage thereto when said at least one of said elements is to be put in said second optical state, said second driving voltage being smaller than a second limiting voltage below which the first optical state spontaneously transforms into said second optical state, said second limiting voltage being less than or equal to said first limiting voltage; wherein said writing voltage is selected to have a value outside a voltage range extending from said first driving voltage to said second driving voltage.

Claim 13

A liquid crystal display according to claim 10, wherein one of the orienting layers is rubbed.

Claim 14

A liquid crystal display according to claims 10 or 11, wherein the spacers comprise glass fibers or glass balls.

Claim 15

A liquid crystal display according to claim 10, comprising: a reflector mounted adjacent one of said substrate plates.

Claim 16

A liquid crystal display according to claims 1 or 2, comprising: an internal reflector made with aluminum pigment and disposed between said substrate plates.

Claim 17

A liquid crystal display according to claim 12, comprising: an internal reflector made with aluminum pigment and disposed between said substrate plates.

Claim 18

A liquid crystal display according to claim 10, further comprising: multiplexing means for dividing the display elements into at least one writing region in which information being displayed by said display elements can be changed and into at least one holding region in which no changes in the optical states of the display elements can be made, and said means for applying said writing voltage includes means for simultaneously applying said writing voltage to all the display elements in said at least one writing region.