Granted Patent B2

US 6,858,266 · App. 10/319,870 · Granted Feb 22, 2005

Abstract

Claims (58)

1. A device comprising:

a liquid crystal composition including a liquid crystal and a liquid crystal domain stabilizing compound, wherein the liquid crystal composition switches between a strongly scattering state of a first plurality of smaller liquid crystal domains that strongly scatters a predetermined light and a weakly scattering state of a second plurality of larger liquid crystal domains that weakly scatters the predetermined light; and

a liquid crystal containment structure defining a space for the liquid crystal composition.

2. The device of claim 1 , wherein the weakly scattering state is stable and the strongly scattering state is stable.

3. The device of claim 1 , wherein the liquid crystal in both the smaller liquid crystal domains and the larger liquid crystal domains possesses helical axes that are randomly oriented.

4. The device of claim 1 , further comprising:

an electric field generating apparatus that electrically induces the change of the strongly scattering state to the weakly scattering state, and the change of the weakly scattering state to the strongly scattering state.

5. The device of claim 1 , further including a colored surface positioned to absorb a portion of the predetermined light that passes through the liquid crystal composition in the weakly scattering state such that an observer sees a predetermined color.

6. The device of claim 1 , further including a receiver.

7. The device of claim 1 , wherein the structure is substantially transparent to the predetermined light to allow entry of the predetermined light into the structure, through the liquid crystal composition, and exit of the predetermined light from the structure in the weakly scattering state.

8. The device of claim 1 , wherein the liquid crystal domain stabilizing compound is a small molecule liquid crystal domain stabilizing compound and wherein the liquid crystal composition further includes a macromolecule liquid crystal domain stabilizing compound.

9. The device of claim 1 , wherein the liquid crystal domain stabilizing compound has formula 1

wherein:

A1 is an electron acceptor moiety;

C1 is a conjugated bridging moiety;

D1 is an electron donor moiety;

S1 is a liquid crystal compatibilizing moiety; and

a′ is an integer.

10. The device of claim 1 , wherein the liquid crystal domain stabilizing compound has formula (3)

wherein:

D3 is an electron donor moiety;

C3 is a conjugated bridging moiety;

A3 is an electron acceptor moiety;

S3 is a liquid crystal compatibilizing moiety; and

b′ is an integer.

11. The device of claim 1 , wherein the liquid crystal domain stabilizing compound has formula (4)

wherein:

D4 is an electron donor moiety;

C4 is a conjugated bridging moiety;

A4 is an electron acceptor moiety;

S4 is a liquid crystal compatibilizing moiety;

b″ is an integer;

Z4 is a polymerizable moiety; and

e″ is the degree of polymerization.

12. The device of claim 1 , wherein the liquid crystal domain stabilizing compound has formula (5)

wherein:

D5 is an electron donor moiety;

C5 is a conjugated bridging moiety;

A5 is an electron acceptor moiety;

R5 is a spacer moiety;

S5 is a liquid crystal compatibilizing moiety; and

c′ is an integer.

13. The device of claim 1 , wherein the liquid crystal domain stabilizing compound has formula (6)

wherein:

D6 is an electron donor moiety;

C6 is at conjugated bridging moiety;

A6 is an electron acceptor moiety;

R6 is a spacer moiety;

S6 is a liquid crystal compatibilizing moiety;

c′ is au integer;

Z6 is a polymerizable moiety; and

e″ is the degree of polymerization.

14. A method comprising:

providing a liquid crystal composition including a liquid crystal and a liquid crystal domain stabilizing compound, wherein the liquid crystal composition is switchable between a strongly scatters state of a first plurality of smaller liquid crystal domains that strongly scatters a predetermined light and a weakly scattering state of a second plurality of larger liquid crystal domains that weakly scatters the predetermined light;

changing the weakly scattering state to the strongly scattering state by applying a first electric field to yield an unstable state of a single liquid crystal domain and then reducing the first electric field to a strongly scattering state inducing level to yield the strongly scattering state; and

changing the strongly scattering state to the weakly scattering state by applying a second electric field weaker than the first electric field but stronger than the strongly scattering state inducing level.

15. The method of claim 14 , wherein the weakly scattering state is stable and the strongly scattering state is stable.

16. The method of claim 14 , wherein the liquid crystal in both the smaller liquid crystal domains and the larger liquid crystal domains possesses helical axes that are randomly oriented.

Assignments (8)