Ultra fast response, multistable reflective cholesteric liquid crystal displays

Claim 2

A liquid crystal cell structure comprising: a first solid substrate having a first inner surface coated with a first conductive layer; a second solid substrate having a second inner surface coated with a second conductive layer; and a substantially indefinite zero field multistable cholesteric liquid crystal mix located in a space between the first inner surface of the first solid substrate and the second inner surface of the second solid substrate, the liquid crystal mix comprising a surface active agent; a plurality of liquid crystals; and at least one twist agent forming multiple cholesteric domains; wherein each of the multiple cholesteric domains is a visible or near-visible reflective unit; wherein an orientation of each of the multiple cholesteric domains can be changed by application of a voltage pulse; liquid crystal mix is below about 150 milliseconds.

Claim 3

The liquid crystal cell structure of claim 1, wherein the first conductive layer is coated with a first amorphous boundary layer.

Claim 4

The liquid crystal cell structure of claim 2, wherein the first amorphous boundary layer comprises a polyimide.

Claim 5

The liquid crystal cell structure of claim 2, wherein the first amorphous boundary layer comprises a silane.

Claim 6

The liquid crystal cell structure of claim 2, wherein helical axes of multiple cholesteric domains are oriented in random directions at the interface with the respective boundary layers.

Claim 7

The liquid crystal cell structure of claim 1, wherein the second conductive layer is coated with a second amorphous boundary layer.

Claim 8

The liquid crystal cell structure of claim 6, wherein the second amorphous boundary layer comprises a polyimide.

Claim 9

The liquid crystal cell structure of claim 6, wherein the second amorphous boundary layer comprises a silane.

Claim 10

The liquid crystal cell structure of claim 6, wherein helical axes of multiple cholesteric domains are oriented in random directions at the interface with the respective boundary layers.

Claim 11

The liquid crystal cell structure of claim 1, wherein the liquid crystal mix is substantially free of polymer additive.

Claim 12

The liquid crystal cell structure of claim 1, wherein the surface active agent is a non-ionic surface active agent in an amount from about 0.1% to about 10% by weight, based on the total weight of the liquid crystal mix.

Claim 13

The liquid crystal cell structure of claim 1, wherein the surface active agent is a non-ionic surface active agent in an amount from about 1% to about 3% by weight, based on the total weight of the liquid crystal mix.

Claim 14

The liquid crystal cell structure of claim 1, wherein the relaxation time is below about 150 microseconds.

Claim 15

The liquid crystal cell structure of claim 1, further comprising up to about 5% by weight of water, based on the total weight of the liquid crystal mix.

Claim 16

A liquid crystal cell structure comprising: a first solid substrate having a first inner surface coated with a first conductive layer; a second solid substrate having a second inner surface coated with a second conductive layer; and a substantially indefinite zero field multistable cholesteric liquid crystal mix located in a space between the first inner surface of the first solid substrate and the second inner surface of the second solid substrate, the liquid mix being substantially free of polymer additive, and the liquid crystal mix comprising a non-ionic surface active agent; plurality of liquid crystals; and at least one twist agent forming multiple cholesteric domains; wherein each of the multiple cholesteric domains is a visible or near-visible reflective unit; and wherein relaxation time of the liquid crystal mix is below about 150 milliseconds.

Claim 17

A liquid crystal cell structure comprising: a first solid substrate having a first inner surface coated with a first conductive layer; a second solid substrate having a second inner surface coated with a second conductive layer; and a substantially indefinite zero field multistable cholesteric liquid crystal mix located in a space between the first inner surface of the first solid substrate and the second inner surface of the second solid substrate, the liquid mix being substantially free of polymer additive, and the liquid crystal mix comprising a non-ionic surface active agent; plurality of liquid crystals; and at least one twist agent forming multiple cholesteric domains; wherein each of the multiple cholesteric domains is a visible or near-visible reflective unit; and wherein relaxation time of the liquid crystal mix is below about 150 milliseconds.

Claim 18

The liquid crystal cell structure of claim 15, wherein the first conductive layer is coated with a first amorphous boundary layer.

Claim 19

The liquid crystal cell structure of claim 16, wherein the first amorphous boundary layer comprises a polyimide.

Claim 20

The liquid crystal cell structure of claim 16, wherein the first amorphous boundary layer comprises a silane.

Claim 21

The liquid crystal cell structure of claim 16, wherein helical axes of multiple cholesteric domains are oriented in random directions at the interface with the respective boundary layers.

Claim 22

The liquid crystal cell structure of claim 15, wherein the second conductive layer is coated with a second amorphous boundary layer.

Claim 23

The liquid crystal cell structure of claim 20, wherein the second amorphous boundary layer comprises a polyimide.

Claim 24

The liquid crystal cell structure of claim 20, wherein the second amorphous boundary layer comprises a silane.

Claim 25

The liquid crystal cell structure of claim 20, wherein helical axes of multiple cholesteric domains are oriented in random directions at the interface with the respective boundary layers.

Claim 26

The liquid crystal cell structure of claim 15, wherein the non-ionic surface active agent is in an amount from about 0.1% to about 10% by weight, based on the total weight of the liquid crystal mix.

Claim 27

The liquid crystal cell structure of claim 15, wherein the non-ionic surface active agent is in an amount from about 1% to about 3% by weight, based on the total weight of the liquid crystal mix.

Claim 28

The liquid crystal cell structure of claim 15, wherein the relaxation time is below about 150 microseconds.

Claim 29

The liquid crystal cell structure of claim 15, further comprising up to about 5% by weight of water, based on the total weight of the liquid crystal mix.

Claim 30

A liquid crystal cell structure comprising: a first solid substrate having a first inner surface coated with a first coating comprising a first conductive layer; a second solid substrate having a second inner surface coated with a second coating comprising a second conductive layer; and a substantially indefinite zero field multistable cholesteric liquid crystal mix located in a space between the first inner surface of the first solid substrate and the second inner surface of the second solid substrate, the liquid mix being substantially free of polymer additive, and the liquid crystal mix comprising a non-ionic surface active agent in a range of from about 0.1% to about 10% by weight, based on the total weight of the liquid crystal mix; a plurality of liquid crystals; and at least one twist agent forming multiple cholesteric domains; wherein each of the multiple cholesteric domains is a visible or near-visible reflective unit; wherein an orientation of each of the multiple cholesteric domains can be changed by application of a voltage pulse; wherein the orientation of each of the multiple cholesteric domains is substantially free of interactions among the multiple cholesteric domains and also substantially free of interaction among the multiple cholesteric domains and the first and second solid substrates to yield zero field multistability; and wherein relaxation time of the liquid crystal mix is below about 150 microseconds.

Claim 31

A liquid crystal cell structure comprising: a first solid substrate having a first inner surface coated with a first coating comprising a first conductive layer; a second solid substrate having a second inner surface coated with a second coating comprising a second conductive layer; and a substantially indefinite zero field multistable cholesteric liquid crystal mix located in a space between the first inner surface of the first solid substrate and the second inner surface of the second solid substrate, the liquid mix being substantially free of polymer additive, and the liquid crystal mix comprising a non-ionic surface active agent in a range of from about 0.1% to about 10% by weight, based on the total weight of the liquid crystal mix; a plurality of liquid crystals; and at least one twist agent forming multiple cholesteric domains; wherein each of the multiple cholesteric domains is a visible or near-visible reflective unit; wherein an orientation of each of the multiple cholesteric domains can be changed by application of a voltage pulse; wherein the orientation of each of the multiple cholesteric domains is substantially free of interactions among the multiple cholesteric domains and also substantially free of interaction among the multiple cholesteric domains and the first and second solid substrates to yield zero field multistability; and wherein relaxation time of the liquid crystal mix is below about 150 microseconds.

Claim 32

The liquid crystal cell structure of claim 28, wherein the non-ionic surface active agent is in an amount from about 1% to about 3% by weight, based on the total weight of the liquid crystal mix.

Claim 33

The liquid crystal cell structure of claim 28, further comprising up to about 5% by weight of water, based on the total weight of the liquid crystal mix.

Claim 36

The method of claim 31 further comprising: removing the driving voltage across the liquid crystal material whereby the domain orientation is transformed from one state to a different state.

Claim 37

The method of claim 31, wherein the driving voltage is a single voltage pulse.

Claim 38

The method of claim 33, wherein the single voltage pulse allows achievement of an unlimited gray scale capability.

Claim 39

The method of claim 31, wherein the driving voltage is a succession of pulses.

Claim 40

The method of claim 35, wherein the succession of pulses allows an unlimited gray scale capability.

Claim 41

The method of claim 31, wherein the driving voltage is applied by means of a matrix drive method wherein: V.sub.N =(V.sub.R -V.sub.S)/2; and wherein V N is the minimum cross-talk voltage, V R is the voltage pulse required to achieve the maximum zero field stable reflective state, and V S is the driving voltage employed to establish domain structures intermediate between the planar and focal-conic extremes.

Claim 42

The method of claim 37, wherein V N is smaller than V T , and wherein V T is the threshold voltage.

Claim 43

The method of claim 31, wherein the speed of changing the domain orientation of the liquid crystal material is dependent on both the driving voltage and the width of the voltage pulse.

Claim 44

The method of claim 31, wherein the relaxation time is less than about 150 microseconds.