Liquid crystal element

1. A liquid crystal element comprising one pair of electrodes of which at least one is a transparent electrode and a liquid crystal layer between the pair of the electrodes, wherein the liquid crystal layer contains at least two compositions of dual frequency addressable smectic liquid crystal compositions having different threshold voltages.

2. A liquid crystal element according to claim 1 , wherein the at least two compositions of dual frequency addressable smectic liquid crystal compositions having different threshold voltages have cross-over frequencies that are different from each other respectively.

3. A liquid crystal element according to claim 1 , wherein:

the at least two compositions of dual frequency addressable smectic liquid crystal compositions having different threshold voltages comprise a first dual frequency addressable smectic liquid crystal composition and a second dual frequency addressable smectic liquid crystal composition;

Ea represents a threshold voltage at a low frequency and E′a represents a threshold voltage at a high frequency of the first dual frequency addressable smectic liquid crystal composition;

Eb represents a threshold voltage at a low frequency as and E′b represents a threshold voltage at a high frequency of the second dual frequency addressable smectic liquid crystal composition; and

Ea is smaller than Eb, and E′a is smaller than E′b.

4. A liquid crystal element according to claim 1 , wherein the at least two compositions of dual frequency addressable smectic liquid crystal compositions having different threshold voltages contain dichroic dyes respectively, and the absorption of the dichroic dyes has at least one relationship of complementary colors selected from the group consisting of yellow and blue, magenta and green, and cyan and red.

5. A liquid crystal element according to claim 1 , wherein the at least two compositions of dual frequency addressable smectic liquid crystal compositions having different threshold voltages comprise a first dual frequency addressable smectic liquid crystal composition, a second dual frequency addressable smectic liquid crystal composition, and a third dual frequency addressable smectic liquid crystal composition having different threshold voltages.

6. A liquid crystal element according to claim 5 , wherein:

Ea represents a threshold voltage at a low frequency and E′a represents a threshold voltage at a high frequency of the first dual frequency addressable smectic liquid crystal composition;

Eb represents a threshold voltage at a low frequency and E′b represents a threshold voltage at a high frequency of the second dual frequency addressable smectic liquid crystal composition;

Ec represents a threshold voltage at a low frequency and E′c represents a threshold voltage at a high frequency of the third dual frequency addressable smectic liquid crystal composition; and

the relationships of Ea <Eb <Ec, and E′a <E′b <E′c are satisfied.

7. A liquid crystal element according to claim 5 , wherein the first dual frequency addressable smectic liquid crystal composition, the second dual frequency addressable smectic liquid crystal composition, and third dual frequency addressable smectic liquid crystal composition contain dichroic dyes of different absorptions respectively, and each dichroic dye shows absorption for any one of yellow, magenta, and cyan.

8. A liquid crystal element according to claim 1 , wherein the liquid crystal layer is laminated.

9. A liquid crystal element according to claim 8 , wherein the liquid crystal layer is a polymer medium layer in which the dual frequency addressable smectic liquid crystal compositions are dispersed in the polymer medium, and the polymer medium layer is laminated.

10. A liquid crystal element according to claim 9 , wherein the liquid crystal layer contains the dual frequency addressable smectic liquid crystal compositions in the form of microcapsules.

11. A liquid crystal element according to claim 1 , wherein the dual frequency addressable smectic liquid crystal compositions are mixtures of a smectic liquid crystal and a dual frequency addressable nematic liquid crystal.

12. A liquid crystal element according to claim 4 , wherein at least one of the dichroic dyes is a dye having a substituent represented by the following Formula (1):

-(Het) j -{(B 1 ) p -(Q 1 ) q -(B 2 ) r } n -C 1

wherein Het represents an oxygen atom or sulfur atom; B 1 and B 2 each independently represent an arylene group, a hetero-arylene group, or a bivalent cycloaliphatic hydrocarbon group; Q 1 represents a bivalent linking group; C 1 represents an alkyl group, a cycloalkyl group, an alkoxy group, an alkoxycarbonyl group, an acyl group, or an acyloxy group; j represents 0 or 1; p, q, and r each independently represent an integer from 0 to 5; n represents an integer of from 1 to 3; (p +r)×n is an integer of 3 to 10; when p is 2 or larger, two or more groups represented by B 1 may be the same or different; and when q is 2 or larger, two or more groups represented by Q 1 may be the same or different; when r is 2 or larger, two or more groups represented by B 2 may be the same or different; when n is 2 or larger, two or more groups represented by {(B 1 ) p -(Q 1 ) q -(B 2 ) r }may be the same or different

13. A liquid crystal element according to claim 4 , wherein the dichroic dye is a compound represented by the following Formula (2):

wherein at least one of R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , and R 8 is -(Het) j -{(B 1 ) p -(Q 1 ) q -(B 2 ) r } n -C 1 and the remaining groups each independently represent a hydrogen atom or a substituent; Het represents an oxygen atom or a sulfur atom; B 1 and B 2 each independently represent an arylene group, a heteroarylene group, or a divalent alicyclic hydrocarbon group; Q 1 represents a divalent linking group; C 1 represents an alkyl group, a cycloalkyl group, an alkoxy group, an alkoxycarbonyl group, an acyl group, or an acyloxy group; j represents 0 or 1; p, q, and r each independently represent an integer of 0 to 5; n represents an integer of 1 to 3; (p+r)×n is an integer of 3 to 10; when p is 2 or larger, two or more groups represented by B 1 may be the same or different; when q is 2 or larger, two or more groups represented by Q 1 may be the same or different; when r is 2 or larger, two or more groups represented by B 2 may be the same or different; and when n is 2 or larger, two or more groups represented by {(B 1 ) p -(Q 1 ) q -(B 2 ) r } may be the same or different.

14. A liquid crystal element according to claim 4 , wherein the dichroic dye is a compound represented by the following Formula (3):

wherein at least one of R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , and R 17 is -(Het) j -{(B 1 ) p (Q 1 ) q -(B 2 ) r } n -C 1 and the remaining groups each independently represent a hydrogen atom or a substituent; Het represents an oxygen atom or a sulfur atom; B 1 and B 2 each independently represent an arylene group, a heteroarylene group, or a divalent alicyclic hydrocarbon group; Q 1 represents a divalent linking group; C 1 represents an alkyl group, a cycloalkyl group, an alkoxy group, an alkoxycarbonyl group, an acyl group, or an acyloxy group; j represents 0 or 1; p, q, and r each independently represent an integer of 0 to 5; n represents an integer of 1 to 3; (p+r)×n is an integer of 3 to 10; when p is 2 or larger, two or more groups represented by B 1 may be the same or different; when q is 2 or larger, two or more groups represented by Q 1 may be the same or different; when r is 2 or larger, two or more groups represented by B 2 may be the same or different; and when n is 2 or larger, two or more groups represented by {(B 1 ) p -(Q 1 ) q -(B 2 ) r } may be the same or different.

15. A liquid crystal element according to claim 1 , wherein one of the dual frequency addressable smectic liquid crystal compositions contains a compound represented by the following Formula (4):

T 1 -{(D 1 ) e -L 1 } m -(D 2 ) k -T 2

wherein D 1 and D 2 each independently represent an arylene group, a heteroarylene group, or a bivalent cycloaliphatic hydrocarbon group; L 1 represents a bivalent linking group; T 1 and T 2 each independently represent an alkyl group, an alkoxy group, an alkoxycarbonyl group, an acyl group, an acyloxy group, a halogen atom or a cyano group; e represents an integer of from 1 to 3; m represents an integer of from 1 to 3; and k represents 1 or 2.

16. A liquid crystal element according to claim 15 , wherein L 1 in the Formula (4) is an ester group or an alkyleneoxy group.

17. A liquid crystal element according to claim 15 , wherein the combination of e, m, and k in the Formula (4) is any one of the following (i) to (iii):

(i) e=1,m=2, and k=1;

(ii) e=2,m=1, and k=1; or

(iii) e=2,m=1, and k=2.

18. A liquid crystal element according to claim 11 , wherein the mixing ratio of the dual frequency addressable nematic liquid crystal and the smectic liquid crystal is from 20 mol %: 80 mol % to 99 mol %: 1 mol %.

19. A liquid crystal element according to claim 11 , wherein the mixing ratio of the dual frequency addressable nematic liquid crystal and the smectic liquid crystal is from 70 mol %:30 mol % to 90 mol %:10 mol %.