LIQUID CRYSTAL COMPOSITION AND LIQUID CRYSTAL DISPLAY DEVICE THEREOF

Abstract

A liquid crystal composition and a liquid crystal display device including the liquid crystal composition include at least one compound of general formula I and at least one compound of general formula II. Compared with the prior art, the liquid crystal composition has a smaller voltage change rate at high and low temperatures and a shorter low temperature response time, while maintaining an appropriate optical anisotropy, an appropriate clearing point, an appropriate absolute value of dielectric anisotropy, such that the liquid crystal display device having the liquid crystal composition has a better display and a faster response speed.

##STR00001##

Claims

1. A liquid crystal composition, wherein the liquid crystal composition comprises: at least one compound of general formula I ##STR00099## and at least one compound of general formula II ##STR00100## in which, R.sub.1 and R.sub.2 each independently represents —H, halogen, C.sub.1-12 linear or branched alkyl, ##STR00101## wherein one or more nonadjacent —CH.sub.2— in the C.sub.1-12 linear or branched alkyl can each be independently replaced by —CH═CH—, —C≡C—, —O—, —CO—, —CO—O— or —O—CO—, and one or more —H in ##STR00102## can each be independently substituted by —F or —Cl; R.sub.3 and R.sub.4 each independently represents C.sub.1-12 linear or branched alkyl, ##STR00103## wherein one or more nonadjacent —CH.sub.2— in the C.sub.1-12 linear or branched alkyl can each be independently replaced by —CH═CH—, —C≡C—, —O—, —CO—, —CO—O— or —O—CO—; ring ##STR00104## and ring ##STR00105## each independently represents ##STR00106## wherein one or more —CH.sub.2— in ##STR00107## can be replaced by —O—, and one or more single bond in the rings can be replaced by double bond, wherein one or more —H on ##STR00108## can each be independently substituted by —F, —Cl, —CN, —CH.sub.3 or —OCH.sub.3, and one or more —CH═ in the rings can be replaced by —N═; X.sub.1 represents —O—, —S—, —CO—, —CF.sub.2—, —NH— or —NF—; Y.sub.1, Y.sub.2, Y.sub.3, Y.sub.4, Y.sub.5 and Y.sub.6 each independently represents —H, halogen, C.sub.1-3 halogenated or unhalogenated alkyl, or C.sub.1-3 halogenated or unhalogenated alkoxy; Z.sub.1 and Z.sub.2 each independently represents single bond, —O—, —S—, —CO—O—, —O—CO—, —CH.sub.2O—, —OCH.sub.2—, —CH═CH—, —C≡C—, —CH.sub.2CH.sub.2—, —CF.sub.2CF.sub.2—, —(CH.sub.2).sub.4—, —CF.sub.2O— or —OCF.sub.2—; and n.sub.1 and n.sub.2 each independently represents 0, 1 or 2, wherein when n.sub.1=2, ring ##STR00109## can be same or different, and Z.sub.1 can be same or different; wherein when n.sub.2=2, ring ##STR00110## can be same or different, and Z.sub.2 can be same or different.

2. The liquid crystal composition according to claim 1, wherein the compound of general formula I is selected from a group consisting of the following compounds: ##STR00111## in which, ring ##STR00112## is defined the same as ring ##STR00113## Z.sub.1′ is defined the same as Z.sub.1; X.sub.1 represents —O—, —S— or —CO—.

3. The liquid crystal composition according to claim 1, wherein the compound of general formula II is selected from a group consisting of the following compounds: ##STR00114## ##STR00115##

4. The liquid crystal composition according to claim 1, wherein the compound of general formula I provides 0.1-40 wt. % of the total weight of the liquid crystal composition; and the compound of general formula II provides 0.1-70 wt. % of the total weight of the liquid crystal composition.

5. The liquid crystal composition according to claim 1, wherein the liquid crystal composition further comprises at least one compound of general formula III: ##STR00116## in which, R.sub.5 and R.sub.6 each independently represents halogen, C.sub.1-12 linear or branched alkyl, ##STR00117## wherein one or more nonadjacent —CH.sub.2— in the C.sub.1-12 linear or branched alkyl can each be independently replaced by —CH═CH—, —C≡C—, —O—, —CO—, —CO—O— or —O—CO—, and one or more —H in aforementioned groups can each be independently substituted by —F or —Cl; ring ##STR00118## and ring ##STR00119## each independently represents ##STR00120## wherein one or more —H on ##STR00121## can each be independently substituted by —F, —Cl, —CN, —CH.sub.3 or —OCH.sub.3, and one or more —CH═ in the rings can be replaced by —N═; and T.sub.1, T.sub.2, T.sub.3, T.sub.4, T.sub.5, T.sub.6, T.sub.7 and T.sub.8 each independently represents —H, —F, —Cl, —CN, —CH.sub.3 or —OCH.sub.3.

6. The liquid crystal composition according to claim 5, wherein the compound of general formula III is selected from a group consisting of the following compounds: ##STR00122## in which, R.sub.5 and R.sub.6 each independently represents C.sub.1-10 linear or branched alkyl, ##STR00123## C.sub.1-9 linear or branched alkoxy, or C.sub.2-10 linear or branched alkenyl; T.sub.9, T.sub.10 and T.sub.11 each independently represents —H, —F, —Cl, —CN, —CH.sub.3 or —OCH.sub.3; and X.sub.2 represents —F, —CF.sub.3, —OCF.sub.3 or —CH.sub.2CH.sub.2CH═CF.sub.2.

7. The liquid crystal composition according to any one of claim 5, wherein the compound of general formula III provides 0.1-50 wt. % of the total weight of the liquid crystal composition.

8. The liquid crystal composition according to claim 1, wherein the liquid crystal composition further comprises at least one compound of general formula M: ##STR00124## in which, R.sub.M1 and R.sub.M2 each independently represents C.sub.1-12 linear or branched alkyl, ##STR00125## wherein one or more nonadjacent —CH.sub.2— in the C.sub.1-12 linear or branched alkyl can each be independently replaced by —CH═CH—, —C≡C—, —O—, —CO—, —CO—O— or —O—CO—; ring ##STR00126## ring ##STR00127## and ring ##STR00128## each independently represents ##STR00129## wherein one or more —CH.sub.2— in ##STR00130## can be replaced by —O—, one or more single bond in the ring can be replaced by double bond, wherein at most one —H on ##STR00131## can be substituted by halogen; Z.sub.M1 and Z.sub.M2 each independently represents single bond, —CO—O—, —O—CO—, —CH.sub.2O—, —OCH.sub.2—, —C≡C—, —CH═CH—, —CH.sub.2CH.sub.2— or —(CH.sub.2).sub.4—; and n.sub.M represents 0, 1 or 2, wherein when n.sub.M=2, ring ##STR00132## can be same or different, Z.sub.M2 can be same or different; and when n.sub.M=1 or 2, at least one of ring ##STR00133## ring ##STR00134## and ring ##STR00135## is non-aromatic ring.

9. The liquid crystal composition according to claim 1, wherein the liquid crystal composition further comprises at least one compound of general formula N: ##STR00136## in which, R.sub.N1 and R.sub.N2 each independently represents C.sub.1-12 linear or branched alkyl, ##STR00137## wherein one or more nonadjacent —CH.sub.2— in the C.sub.1-12 linear or branched alkyl can each be independently replaced by —CH═CH—, —C≡C—, —O—, —CO—, —CO—O— or —O—CO—; ring ##STR00138## and ring ##STR00139## each independently represents ##STR00140## wherein one or more —CH.sub.2— in ##STR00141## can be replaced by —O—, and one or more single bond in the ring can be replaced by double bond, wherein one or more —H on ##STR00142## can each be independently substituted by —F, —Cl, —CN, —CH.sub.3 or —OCH.sub.3, and one or more —CH═ in the ring can be replaced by —N═; Z.sub.N1 and Z.sub.N2 each independently represents single bond, —CO—O—, —O—CO—, —CH.sub.2O—, —OCH.sub.2—, —CH═CH—, —C≡C—, —CH.sub.2CH.sub.2—, —CF.sub.2CF.sub.2—, —(CH.sub.2).sub.4—, —CF.sub.2O— or —OCF.sub.2—; L.sub.N1 and L.sub.N2 each independently represents —H, C.sub.1-3 alkyl or halogen; n.sub.N1 represents 0, 1, 2 or 3, n.sub.N2 represents 0 or 1, and 0≤n.sub.N1+n.sub.N2≤3, wherein when n.sub.N1=2 or 3, ring ##STR00143## can be same or different, Z.sub.N1 can be same or different; when 0≤n.sub.N1+n.sub.N2≤2, compounds of general formula N do not comprise terphenyl structure; and when n.sub.N1+n.sub.N2=3, compounds of general formula N do not comprise quaterphenyl structure.

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

Description

DETAILED DESCRIPTION OF THE INVENTION

[0131] 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.

[0132] 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:

TABLE-US-00001 TABLE 1 Codes of the group structures of liquid crystal compounds Unit structure of group Code Name of group [00089] C 1,4-cyclohexylidene [00090] P 1,4-phenylene [00091] G 2-fluoro-1,4-phenylene [00092] U 2,6-difluoro-1,4- phenylene [00093] W 2,3-difluoro-1,4- phenylene [00094] C(5) cyclopentyl [00095] B(O) 4,6-difluoro-dibenzo [b,d]furan-3,7-diyl [00096] B(S) 4,6-difluoro- dibenzo[b,d] thiophene-3,7- diyl [00097] Na naphthyl —CH.sub.2O— 1O methyleneoxy —CH.sub.2CH.sub.2— 2 ethyl bridge bond —CO— CO carbonyl —F F fluorine substituent —O— O oxygen substituent —CH═CH— or —CH═CH.sub.2 V ethenyl —C.sub.nH.sub.2n+1 n (n alkyl repre- sents an inte- ger of 1-12)

[0133] Take the compound with following structural formula as an example:

##STR00098##

[0134] 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 1,4-cyclohexylidene, G represents 2-fluoro-1,4-phenylene, and F represents fluoro substituent.

[0135] The abbreviated codes of the test items in the following Examples are as follows:

[0136] Cp (° C.) clearing point (nematic-isotropy phases transition temperature)

[0137] Δn optical anisotropy (589 nm, 25° C.)

[0138] Δε dielectric anisotropy (1 KHz, 25° C.)

[0139] DV/DT voltage change rate at high and low temperatures (%)

[0140] τ.sub.(−20° C.) low temperature response time (ms)

[0141] in which,

[0142] Cp: tested and obtained through melting point apparatus;

[0143] Δn: tested and obtained by using Abbe refractometer under sodium lamp (589 nm) light source at 25° C.;

[0144] Δε: Δε=ε.sub.//−ε.sub.⊥, in which, ε.sub.// is the dielectric constant parallel to the molecular axis, ε.sub.⊥ is the dielectric constant perpendicular to the molecular axis, with the test conditions: 25° C., 1 KHz, VA type test cell with a cell gap of 6 μm;

[0145] DV/DT: tested by using DMS505 tester; with the test conditions: test frequency: 60 Hz, test waveform: square, high temperature 60° C., room temperature 20° C.;

[0146] τ.sub.(−20° C.): tested and obtained by using DMS505 tester at −20° C.; with the test conditions: IPS type test cell with a cell gap of 3.5 driving voltage 5.5 V.

[0147] 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.

[0148] 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, such as heating, ultrasonic wave, or suspension.

[0149] 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

[0150] 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.

TABLE-US-00002 TABLE 2 Formulation and test performances of liquid crystal composition Test results for Code of Code of the performance component Weight percent structure parameters 3CWO2 14.5 N-2 Δn 0.102 3CCWO2 13 N-5 Cp 89 2CCWO2 8.5 N-5 Δε −3.1 5CWO2 8 N-2 DV/DT 21 2PWP3 6 II-3 τ.sub.(−20□) 460 3CCV 21.5 M-1 3CCV1 8 M-1 1PP2V 2 M-6 3CPWO2 5 N-11 3CCWO3 4.5 N-5 VCCP1 2 M-12 3CPP2 3 M-16 3CCP2 3 M-12 3CPO2 1 M-2 Total 100

Example 1

[0151] 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.

TABLE-US-00003 TABLE 3 Formulation and test performances of liquid crystal composition Test results for Code of Code of the performance component Weight percent structure parameters 3CWO2 14.5 N-2 Δn 0.104 3CCWO2 13 N-5 Cp 89 2CCWO2 8.5 N-5 Δε −3.6 5CWO2 8 N-2 DV/DT 17 2PWP3 6 II-3 τ.sub.(−20□) 390 3CCV 21.5 M-1 3CCV1 8 M-1 1PP2V 2 M-6 C(5)1OB(O)O5 4 I-1 3CCWO3 5.5 N-5 VCCP1 2 M-12 3CPP2 3 M-16 2CPP2 3 M-16 3CPO2 1 M-2 Total 100

Example 2

[0152] 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.

TABLE-US-00004 TABLE 4 Formulation and test performances of liquid crystal composition Test results for Code of Code of the performance component Weight percent structure parameters 3CWO2 14.5 N-2 Δn 0.104 3CCWO2 10 N-5 Cp 87 2CCWO2 8.5 N-5 Δε −4 5CWO2 8 N-2 DV/DT 14 2PWP3 6 II-3 τ.sub.(−20□) 360 3CCV 21.5 M-1 3CCV1 8 M-1 1PP2V 2 M-6 3OB(O)O4 5 I-1 4OB(CO)5 3 I-1 3CCWO3 4.5 N-5 VCCP1 2 M-12 3CPP2 3 M-16 3CGPC3 2 M-25 3PPGGF 2 III-2 Total 100

Example 3

[0153] 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.

TABLE-US-00005 TABLE 5 Formulation and test performances of liquid crystal composition Test results for Code of Code of the performance component Weight percent structure parameters 3CWO2 14.5 N-2 Δn 0.11 3CCWO2 8 N-5 Cp 89 2CCWO2 6 N-5 Δε −4.9 5CWO2 8 N-2 DV/DT 12 2PWP3 6 II-3 τ.sub.(−20□) 340 3CCV 21.5 M-1 3CCV1 8 M-1 1PP2V 2 M-6 3OB(S)O3 8 I-1 C(5)B(O)O6 8.5 I-1 VCCP1 2 M-12 3CPP2 1.5 M-16 3CPPC3 2.5 M-23 5PGP(Na) 1 III-1 3PPGUF 2.5 III-2 Total 100

[0154] It can be seen from the comparison between Comparative Example 1 and Example 1 that the liquid crystal composition of the present has a smaller voltage change rate at high and low temperatures and a shorter low temperature response time, while maintaining an appropriate optical anisotropy, an appropriate clearing point, an appropriate absolute value of dielectric anisotropy.

Comparative Example 2

[0155] The liquid crystal composition of Comparative Example 2 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.

TABLE-US-00006 TABLE 6 Formulation and test performances of liquid crystal composition Test results for Code of Code of the performance component Weight percent structure parameters 3CWO2 14.5 N-2 Δn 0.103 3CCWO2 13 N-5 Cp 88 2CCWO2 9.5 N-5 Δε −3.6 5CWO2 8 N-2 DV/DT 22 3OB(O)O4 5 I-1 τ.sub.(−20□) 410 3CCV 21.5 M-1 3CCV1 8 M-1 1PP2V 2 M-6 3CPWO2 5 N-11 3CCWO3 4.5 N-5 VCCP1 2 M-12 3CPP2 3 M-16 3CCP2 3 M-12 3CPO2 1 M-2 Total 100

Example 4

[0156] The liquid crystal composition of Example 4 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.

TABLE-US-00007 TABLE 7 Formulation and test performances of liquid crystal composition Test results for Code of Code of the performance component Weight percent structure parameters 3CWO2 14.5 N-2 Δn 0.104 3CCWO2 13 N-5 Cp 86 2CCWO2 9.5 N-5 Δε −3.5 5CWO2 8 N-2 DV/DT 16 3OB(O)O4 6 I-1 τ.sub.(−20□) 380 3CCV 21.5 M-1 3CCV1 8 M-1 1PP2V 2 M-6 3PWP3 4 II-3 3CCWO3 4.5 N-5 VCCP1 2 M-12 3CPP2 3 M-16 3CCP2 1 M-12 3CPO2 1 M-2 3GGPPF 2 III-2 Total 100

Example 5

[0157] The liquid crystal composition of Example 5 is prepared according to each compound and weight percentage listed in Table 8 and is tested by filling the same between two substrates of a liquid crystal display device.

TABLE-US-00008 TABLE 8 Formulation and test performances of liquid crystal composition Test results for Code of Code of the performance component Weight percent structure parameters 3CWO2 12.5 N-2 Δn 0.106 3CCWO2 9 N-5 Cp 87 2CCWO2 8 N-5 Δε −3.6 5CWO2 8 N-2 DV/DT 13 3OB(O)O4 5 I-1 τ.sub.(−20□) 355 3CCV 21.5 M-1 3CCV1 8 M-1 1PP2V 2 M-6 3PWP3 7 II-3 4PPWO2 8.5 II-4 VCCP1 2 M-12 3CPP2 1 M-16 3CCP2 1 M-12 3CPO2 1 M-2 3GGPPF 3 III-2 C(5)PPGUF 2.5 III-2 Total 100

Example 6

[0158] The liquid crystal composition of Example 6 is prepared according to each compound and weight percentage listed in Table 9 and is tested by filling the same between two substrates of a liquid crystal display device.

TABLE-US-00009 TABLE 9 Formulation and test performances of liquid crystal composition Test results for Code of Code of the performance component Weight percent structure parameters 3CWO2 8.5 N-2 Δn 0.115 3CCWO2 4 N-5 Cp 88 2CCWO2 4 N-5 Δε −3.9 5CWO2 7 N-2 DV/DT 11 3OB(O)O4 5 I-1 τ.sub.(−20□) 350 C(5)1OB(S)O4 5 I-1 3CCV 21.5 M-1 3CCV1 8 M-1 1PP2V 2 M-6 3PWP3 8 II-3 4PPWO2 7.5 II-4 3PWWO3 7.5 II-5 3OPPWO2 3 II-4 VCCP1 2 M-12 3CPP2 1 M-16 3CCP2 1 M-12 3CPO2 1 M-2 3GGPPF 2 III-2 C(5)PPGUF 2 III-2 Total 100

[0159] It can be seen from the comparison between Comparative Example 2 and Example 4 that the liquid crystal composition of the present has a smaller voltage change rate at high and low temperatures and a shorter low temperature response time, while maintaining an appropriate optical anisotropy, an appropriate clearing point, an appropriate absolute value of dielectric anisotropy.

[0160] In conclusion, the liquid crystal composition of the present has a smaller voltage change rate at high and low temperatures and a shorter low temperature response time, while maintaining an appropriate optical anisotropy, an appropriate clearing point, an appropriate absolute value of dielectric anisotropy, such that the liquid crystal display device comprising the liquid crystal composition has a better display and a faster response speed.

[0161] 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.