Liquid crystal composition and display device thereof

Abstract

The present invention discloses a liquid crystal composition comprising at least one compound of general formula I and a display device thereof. The present invention also discloses a liquid crystal display device comprising the liquid crystal composition of the present invention. The liquid crystal composition provided by the present invention has characteristics, such as a high absolute value of negative dielectric anisotropy, a high optical anisotropy, a superior low-temperature stability, a fast response speed and so forth. The liquid crystal display device comprising the liquid crystal composition of the present invention can satisfy the demand for low driving voltage and fast response. ##STR00001##

Claims

1. A liquid crystal composition, wherein the liquid crystal composition comprises: at least one compound selected from a group consisting of the following compounds: ##STR00044## in which, R.sub.1 represents C.sub.1-12 alkyl or alkoxy, or C.sub.2-12 alkenyl or alkenoxy, wherein one or more nonadjacent —CH.sub.2— in the alkyl or alkoxy and the alkenyl or alkenoxy can each be independently replaced by —O— in a manner that oxygen atoms are not directly connected; R.sub.3 represents C.sub.1-7 alkyl or C.sub.2-7 alkenyl; n represents an integer of 2-6.

2. A liquid crystal composition, wherein the liquid crystal composition comprises: (a) at least one compound selected from a group consisting of the following compounds: ##STR00045## (b) at least one compound selected from a group consisting of the following compounds: ##STR00046## in which, R.sub.1 represent C.sub.1-12 alkyl or alkoxy, or C.sub.2-12 alkenyl or alkenoxy, wherein one or more nonadjacent —CH.sub.2— in the alkyl or alkoxy and the alkenyl or alkenoxy can each be independently replaced by —O— in a manner that oxygen atoms are not directly connected; R.sub.3 represents C.sub.1-7 alkyl or C.sub.2-7 alkenyl; and n represents an integer of 2-6.

3. The liquid crystal composition according to claim 2, wherein the at least one compound selected from general formulas I-a and I-b and the at least one compound selected from formula I-c provide from 1 wt % to 35 wt % of the total weight of the liquid crystal composition.

4. The liquid crystal composition according to claim 2, wherein at least one compound selected from general formulas I-a and I-b and the at least one compound selected from formula I-c are selected from a group consisting of the following compounds: ##STR00047## in which, R.sub.1 represent C.sub.1-12 alkyl or alkoxy, or C.sub.2-12 alkenyl or alkenoxy, wherein one or more nonadjacent —CH.sub.2— in the alkyl or alkoxy and the alkenyl or alkenoxy can each be independently replaced by —O— in a manner that oxygen atoms are not directly connected; R.sub.3 represents C.sub.1-7 alkyl or C.sub.2-7 alkenyl; and n represents an integer of 2-6.

5. The liquid crystal composition according to claim 3, wherein the at least one compound selected from general formulas I-a and I-b and the at least one compound selected from formula I-c provides from 5 wt % to 30 wt % of the total weight of the liquid crystal composition.

6. The liquid crystal composition according to claim 5, wherein the liquid crystal composition further comprises at least one compound of general formula II ##STR00048## in which, R.sub.4 and R.sub.5 each independently represents C.sub.1-12 alkyl or alkoxy, or C.sub.2-12 alkenyl or alkenoxy, wherein one or more nonadjacent —CH.sub.2— in the alkyl or alkoxy and the alkenyl or alkenoxy can each be independently replaced by —O— in a manner that oxygen atoms are not directly connected; ring ##STR00049## one or more —CH.sub.2— in the ##STR00050## can be replaced by —O—, one or more H on the ##STR00051## can be substituted by F; Z.sub.1 represents single bond, —CH.sub.2O—, —CF.sub.2O— or —COO—; m represents 0 or 1.

7. The liquid crystal composition according to claim 1, wherein the liquid crystal composition further comprises at least one compound of general formula II ##STR00052## in which, R.sub.4 and R.sub.5 each independently represents C.sub.1-12 alkyl or alkoxy, or C.sub.2-12 alkenyl or alkenoxy, wherein one or more nonadjacent —CH.sub.2— in the alkyl or alkoxy and the alkenyl or alkenoxy can each be independently replaced by —O— in a manner that oxygen atoms are not directly connected; ring ##STR00053## one or more —CH.sub.2— in the ##STR00054## can be replaced by —O—, one or more H on the ##STR00055## can be substituted by F; Z.sub.1 represents single bond, —CH.sub.2O—, —CF.sub.2O— or —COO—; m represents 0 or 1.

8. The liquid crystal composition according to claim 6, wherein the liquid crystal composition further comprises at least one compound of general formula III ##STR00056## in which, R.sub.6 and R.sub.7 each independently represents C.sub.1-12 alkyl or alkoxy, or C.sub.2-12 alkenyl or alkenoxy, wherein one or more nonadjacent —CH.sub.2— in the alkyl or alkoxy and the alkenyl or alkenoxy can each be independently replaced by —O— in a manner that oxygen atoms are not directly connected; ring ##STR00057## and ring ##STR00058## each independently represents ##STR00059## Z.sub.2 represents single bond, —CH.sub.2O—, —CF.sub.2O— or —COO—; p represents 0 or 1.

9. The liquid crystal composition according to claim 7, wherein the liquid crystal composition further comprises at least one compound of general formula III ##STR00060## in which, R.sub.6 and R.sub.7 each independently represents C.sub.1-12 alkyl or alkoxy, or C.sub.2-12 alkenyl or alkenoxy, wherein one or more nonadjacent —CH.sub.2— in the alkyl or alkoxy and the alkenyl or alkenoxy can each be independently replaced by —O— in a manner that oxygen atoms are not directly connected; ring ##STR00061## and ring ##STR00062## each independently represents ##STR00063## Z.sub.2 represents single bond, —CH.sub.2O—, —CF.sub.2O— or —COO—; p represents 0 or 1.

10. A liquid crystal display device comprising the liquid crystal composition of claim 1.

11. A liquid crystal display device comprising the liquid crystal composition of claim 2.

Description

DETAILED EMBODIMENTS

(1) The present invention will be illustrated by combining the detailed embodiments below. It should be noted that, the following examples are exemplary embodiments of the present invention, which are only used to illustrate the present invention, not to limit it. Other combinations and various modifications within the conception of the present invention are possible without departing from the subject matter and scope of the present invention.

(2) Unless specifically indicated, in the present invention, all ratios are weight ratios, and all temperatures are degree centigrade.

(3) For the convenience of the expression, the group structures of the liquid crystal compositions in the following Examples are represented by the codes listed in Table 1:

(4) TABLE-US-00001 TABLE 1 Codes of the group structures of liquid crystal compounds Unit structure of group Code Name of group C 1,4-cyclohexylidene 0 P 1,4-phenylene G 2-fluoro-1,4-phenylene W 2,3-difluoro-1,4-phenylene —CH.sub.2CH.sub.2— 2 ethyl bridge bond —OCF.sub.3 OCF3 trifluoromethoxy —F F fluorine substituent —O— O oxygen substituent —CF.sub.2O— Q difluoro ether group —COO— E ester bridge bond —C.sub.nH.sub.2n+1 or n or m alkyl —C.sub.mH.sub.2m+1 —CH═CH— or V alkenyl —CH═CH.sub.2

(5) Take the compound with following structural formula as an example:

(6) ##STR00043##

(7) Represented by the codes listed in Table 1, this structural formula can be expressed as nCCGF, in which, n in the code represents the number of the carbon atoms of the alkyl on the left, for example, n is “3”, meaning that the alkyl is —C.sub.3H.sub.7; C in the code represents cyclohexyl, G represents 2-fluoro-1,4-phenylene, and F represents fluoro.

(8) The abbreviated codes of the test items in the following Examples are as follows: Cp (° C.) clearing point (nematic-isotropy phases transition temperature) Δn optical anisotropy (589 nm, 25° C.) Δε dielectric anisotropy (1 KHz, 25° C.) γ1 rotational viscosity (mPa*s, at 25° C.) t(−30° C.) low-temperature storage time (h, at −30° C.)

(9) In which, the optical anisotropy is tested and obtained by using abbe refractometer under sodium lamp (589 nm) light source at 25° C.

(10) Δε=ε.sub.∥-ε.sub.⊥, in which, ε.sub.∥ is a dielectric constant parallel to the molecular axis, ε.sub.⊥ is a dielectric constant perpendicular to the molecular axis, with the test conditions: 25° C., 1 KHz, TN90 type test cell with a cell gap of 7 μm.

(11) γ1 is tested and obtained by the TOYO6254 type liquid crystal physical property evaluation system; the test temperature is 25° C., and the test voltage is 90 V.

(12) The ingredients used in the following Examples can be synthesized by well-known methods or obtained by commercial means. These synthetic techniques are routine, and the test results show that the liquid crystal compounds thus prepared meet the criteria for the electronic compounds.

(13) The liquid crystal compositions are prepared according to the formulations of the liquid crystal compositions specified in the following Examples. The preparation of the liquid crystal compositions is proceeded according to the conventional methods in the art, and as an example, the compositions are prepared by mixing the specified formulation via the processing modes, such as heating, ultrasonic processing, suspending processing and so forth.

(14) The liquid crystal composition specified in the following Examples are prepared and studied. The formulas of the liquid crystal compositions and their test results for the performance are shown below.

Comparative Example 1

(15) The liquid crystal composition of Comparative Example 1 is prepared according to each compound and weight percentage listed in Table 2 and is tested by filling the same between two substrates of a liquid crystal display device. The test data are shown in the Table below:

(16) TABLE-US-00002 TABLE 2 Formulation and test performances of liquid crystal composition Code of weight Test results for the Code of component structure percent performance parameters 3CWO4 II-1-10 15 Cp 95 5CWO4 II-1-12 10 Δn 0.114 3CCWO2 II-3-2 15 Δε −3.8 3CCWO5 5 γ1 212 4CCWO2 II-3-3 5 t (−30° C.) >336 5CPWO4 9 3CCV III-1-11 10 4CC3 III-1-6 7 3CPP2 III-4-2 10 3PWP2 5 7PGP3 7 VCCP1 III-3-4 2 Total 100

Example 1

(17) The liquid crystal composition of Example 1 is prepared according to each compound and weight percentage listed in Table 3 and is tested by filling the same between two substrates of a liquid crystal display device. The test data are shown in the Table below:

(18) TABLE-US-00003 TABLE 3 Formulation and test performances of liquid crystal composition Code of Code of weight Test results for the component structure percent performance parameters 3CWO4 II-1-10 11 Cp 96 3CCWO4 II-3-10 4 Δn 0.127 5CWO4 II-1-12 10 Δε −4.9 3PPWO4 I-b-2 10 γ1 187 VCCP1 III-3-4 3 t (−30° C.) >1000 V2CCP1 III-3-6 5 3CCV1 III-1-15 11 2CPWO2 II-4-1 8 3CPWO2 II-4-2 8 4CPWO2 II-4-3 8 5PP1 2 5PWO4 II-2-12 5 3CPP2 III-4-2 5 5CWO2 II-1-4 10 Total 100

Example 2

(19) The liquid crystal composition of Example 2 is prepared according to each compound and weight percentage listed in Table 4 and is tested by filling the same between two substrates of a liquid crystal display device. The test data are shown in the Table below:

(20) TABLE-US-00004 TABLE 4 Formulation and test performances of liquid crystal composition Code of Code of weight Test results for the component structure percent performance parameters 3CWO4 II-1-10 10 Cp 99.7 3CCWO4 II-3-10 7 Δn 0.144 5CWO4 II-1-12 9 Δε −5 3PPWO4 I-b-2 8 γ1 191 V2CCP1 III-3-6 5 t (−30° C.) >1000 3CCV III-1-11 7 4PPWO3 I-a-3 7 5PPWO2 I-4 5 3CPWO2 II-4-2 5 3CPWO4 II-4-8 9 5PP1 6 5PWO4 II-2-12 5 3CPP2 III-4-2 8 5CWO2 II-1-4 9 Total 100

Example 3

(21) The liquid crystal composition of Example 3 is prepared according to each compound and weight percentage listed in Table 5 and is tested by filling the same between two substrates of a liquid crystal display device. The test data are shown in the Table below:

(22) TABLE-US-00005 TABLE 5 Formulation and test performances of iquid crystal composition Code of Code of weight Test results for the component structure percent performance parameters 3CWO4 II-1-10 12 Cp 100 3CCWO4 II-3-10 5 Δn 0.15 5CWO4 II-1-12 8 Δε −4.9 3PPWO4 I-b-2 8 γ1 174 V2CCP1 III-3-6 5 t (−30° C.) >1000 3CCV III-1-11 12 4PPWO3 I-a-3 7 5PPWO2 I-4 5 3PPWO4O1 I-c 5 3CPWO4 II-4-8 4 5PP1 3 3PWO4 II-2-10 5 3CPP2 III-4-2 7 5PPWO4 I-b-4 5 5CWO2 II-1-4 9 Total 100

Example 4

(23) The liquid crystal composition of Example 4 is prepared according to each compound and weight percentage listed in Table 6 and is tested by filling the same between two substrates of a liquid crystal display device. The test data are shown in the Table below:

(24) TABLE-US-00006 TABLE 6 Formulation and test performances of liquid crystal composition Code of Code of weight Test results for the component structure percent performance parameters 3CWO4 II-1-10 9 Cp 96 5CCWO2 II-3-4 5 Δn 0.128 5CWO4 II-1-12 7 Δε −4.9 3PPWO2 I-2 5 γ1 201 VCCP1 III-3-4 3 t (−30° C.) >500 V2CCP1 III-3-6 4 3CCV1 III-1-15 10 2CPWO2 II-4-1 8 3CPWO2 II-4-2 10 4CPWO2 II-4-3 10 5PP1 3 5PWO4 II-2-12 10 3CPP2 III-4-2 6 5CWO2 II-1-4 10 Total 100

Example 5

(25) The liquid crystal composition of Example 5 is prepared according to each compound and weight percentage listed in Table 7 and is tested by filling the same between two substrates of a liquid crystal display device. The test data are shown in the Table below:

(26) TABLE-US-00007 TABLE 7 Formulation and test performances of liquid crystal composition Code of Code of weight Test results for the component structure percent performance parameters 3CWO4 II-1-10 9 Cp 96 5CCWO2 II-3-4 5 Δn 0.128 5CWO4 II-1-12 7 Δε −4.9 3PPWO2 I-2 2 γ1 203 VCCP1 III-3-4 3 t (−30° C.) >1000 V2CCP1 III-3-6 4 3CCV1 III-1-15 10 2CPWO2 II-4-1 8 3CPWO2 II-4-2 10 4CPWO2 II-4-3 10 5PP1 3 5PWO4 II-2-12 10 3CPP2 III-4-2 6 5PPWO2 I-4 3 5CWO2 II-1-4 10 Total 100

(27) It can be seen from the test data of the above Examples that the liquid crystal composition provided by the present invention has characteristics, such as a high absolute value of negative dielectric anisotropy, a high optical anisotropy, a superior low-temperature stability, a fast response speed and so forth. The liquid crystal display device comprising the liquid crystal composition of the present invention can satisfy the demand for low driving voltage and fast response.

(28) The above embodiments are merely illustrative of the technical concepts and features of the present invention, and provided for facilitating the understanding and practice of the present invention by those skilled in the art. However, the protection scope of the invention is not limited thereto. Equivalent variations or modifications made without departing from the spirit and essence of the present invention are intended to be contemplated within the protection scope of the present invention.

INDUSTRIAL APPLICABILITY

(29) The liquid crystal composition related in the present invention can be applied to the field of liquid crystal.