LIQUID CRYSTAL COMPOSITION AND LIQUID CRYSTAL DISPLAY DEVICE THEREOF

Abstract

A liquid crystal composition includes at least one compound represented by formula I and at least one compound represented by formula II. The liquid crystal composition has a relatively large absolute value of dielectric anisotropy, a relatively large K value, a relatively long low-temperature storage time period, a relatively low polymer layer surface roughness, a relatively small pre-tilt angle, a relatively fast speed for forming pre-tilt angle, a relatively low polymer residue, a relatively high VHR and a relatively good pre-tilt angle stability, while maintaining appropriate clearing points, optical anisotropy and rotational viscosity. A liquid crystal display device containing the liquid crystal composition has a relatively wide temperature usage range, relatively good contrast, and relatively good low-temperature mutual solubility. In addition, the production process of PSA-type liquid crystal displays is improved, and at the same time, the problems of image sticking, uneven display and broken bright spots.

##STR00001##

Claims

1. A liquid crystal composition comprising: at least one compound of general formula I: ##STR00134## and at least one compound of general formula II: ##STR00135## wherein, R.sub.1 represents C.sub.1-5 linear or branched, halogenated or unhalogenated alkyl; R.sub.2 represents H, halogen, CN, -Sp.sub.2-P.sub.2 or C.sub.1-12 linear or branched alkyl, ##STR00136## wherein one or more than two nonadjacent CH.sub.2 in the C.sub.1-12 linear or branched alkyl, ##STR00137## can each be independently replaced by CH?CH, C?C, O, CO, COO or OCO, one or more H can each be independently substituted by F or Cl; R.sub.3 represents H, halogen, C.sub.1-12 linear or branched alkyl, ##STR00138## wherein one or more than two 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, COO or OCO in a manner that O are not directly connected to each other, and one or more H on the C.sub.1-12 linear or branched alkyl, ##STR00139## can each be independently substituted by F or Cl; ring ##STR00140## and ring ##STR00141## each independently represents ##STR00142## wherein one or more CH.sub.2 in ##STR00143## 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 ##STR00144## can each be independently substituted by F, Cl or CN, and one or more CH? in the ring can be replaced by N?; A represents ##STR00145## wherein one or more CH.sub.2 in ##STR00146## can each be independently replaced by X.sup.1 or X.sup.2, and one or more single bond in the ring can be replaced by double bond, wherein X.sup.1 represents O or S, X.sup.2 represents C.sub.1-5 linear alkyl; L each independently represents halogen, CN or -Sp.sub.2-P.sub.2; L.sub.1 and L.sub.2 each independently represents H, halogen, C.sub.1-3 halogenated alkyl or C.sub.1-3 halogenated alkoxy; P.sub.1 and P.sub.2 each independently represents polymerizable group; Sp.sub.1 and Sp.sub.2 each independently represents spacer group or single bond; X represents O, S, CO, CF.sub.2, NH or NF; Z.sub.1 and Z.sub.2 each independently represents O, S, CO, COO, OCO, OCOO, CH.sub.2O, OCH.sub.2, CH.sub.2S, SCH.sub.2, CF.sub.2O, OCF.sub.2, CF.sub.2S, SCF.sub.2, (CH.sub.2).sub.n, CF.sub.2CH.sub.2, CH.sub.2CF.sub.2, (CF.sub.2).sub.n, CH?CH, CF?CF, CH?CF, CF?CH, C?C, CH?CHCOO, OCOCH?CH, CH.sub.2CH.sub.2COO, OCOCH.sub.2CH.sub.2, CR.sup.1R.sup.2 or single bond; wherein, R.sup.1 and R.sup.2 each independently represents H or C.sub.1-12 linear or branched alkyl, and n represents an integer of 1-4; Z.sub.3, Z.sub.4 and Z.sub.5 each independently represents single bond, CH.sub.2CH.sub.2, CF.sub.2CF.sub.2, COO, OCO, OCOO, CH?CH, CF?CF, CH.sub.2O or OCH.sub.2; r.sub.1, r.sub.2 and r.sub.3 each independently represents 0, 1, 2 or 3, when r.sub.1, r.sub.2 and r.sub.3 each independently represents 2 or 3, L can be the same or different; n.sub.1 and n.sub.2 each independently represents 0, 1 or 2, and n.sub.1+n.sub.2?1, when n.sub.1 represents 2, ##STR00147## can be the same or different, when n.sub.2 represents 2, ##STR00148## can be the same or different; and n.sub.3 represents 0, 1 or 2, n.sub.4 represents 0 or 1, when n.sub.3 represents 2, ring ##STR00149## can be the same or different, Z.sub.3 can be the 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: ##STR00150## ##STR00151## wherein, R.sub.1 represents C.sub.1-5 linear or branched, halogenated or unhalogenated alkyl; P.sub.1 and P.sub.2 each independently represents polymerizable group; Sp.sub.1 and Sp.sub.2 each independently represents spacer group or single bond; L and L each independently represents F, Cl, CN or -Sp.sub.2-P.sub.2.

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: ##STR00152## ##STR00153## wherein, R.sub.3 represents H, halogen, C.sub.1-12 linear or branched alkyl, ##STR00154## wherein one or more than two 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, COO or OCO in a manner that O are not directly connected to each other, and one or more H on the C.sub.1-12 linear or branched alkyl, ##STR00155## can each be independently substituted by F or Cl; ring ##STR00156## and ring ##STR00157## each independently represents ##STR00158## wherein one or more CH.sub.2 in ##STR00159## 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 ##STR00160## can each be independently substituted by F, Cl or CN, and one or more CH? in the ring can be replaced by N?; and Z.sub.3 and Z.sub.5 each independently represents single bond, CH.sub.2CH.sub.2, CF.sub.2CF.sub.2, COO, OCO, OCOO, CH?CH, CF?CF, CH.sub.2O or OCH.sub.2.

4. The liquid crystal composition according to claim 1, wherein the liquid crystal composition further comprises at least one compound of general formula M: ##STR00161## wherein, R.sub.M1 and R.sub.M2 each independently represents C.sub.1-12 linear or branched alkyl, ##STR00162## wherein one or more than two 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, COO or OCO; ring ##STR00163## ring ##STR00164## and ring ##STR00165## each independently represents ##STR00166## wherein one or more CH.sub.2 in ##STR00167## can be replaced by O, and one or more single bond in the ring can be replaced by double bond, and wherein at most one H on ##STR00168## can be substituted by halogen; Z.sub.M1 and Z.sub.M2 each independently represents single bond, COO, OCO, 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 ##STR00169## can be the same or different, Z.sub.M2 can be the same or different.

5. The liquid crystal composition according to claim 1, wherein the liquid crystal composition further comprises at least one compound of general formula N: ##STR00170## wherein, R.sub.N1 and R.sub.N2 each independently represents C.sub.1-12 linear or branched alkyl, ##STR00171## wherein one or more than two 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, COO or OCO; ring ##STR00172## and ring ##STR00173## each independently represents ##STR00174## wherein one or more CH.sub.2 in ##STR00175## 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 ##STR00176## can each be independently substituted by F, Cl or CN, 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, COO, OCO, 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; and 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 ##STR00177## can be the same or different, Z.sub.N1 can be the same or different.

6. The liquid crystal composition according to claim 2, wherein the compound of general formula I provides 0.001%?5% (in percentage by weight) of the liquid crystal composition.

7. The liquid crystal composition according to claim 3, wherein the compound of general formula II provides 0.1%-25% (in percentage by 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 self-alignment agent of general formula SA: ##STR00178## wherein, R.sub.S1 represents Sp-P, C.sub.1-12 linear or branched alkyl, ##STR00179## wherein one or more than two 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, COO or OCO, and one or more H on the C.sub.1-12 linear or branched alkyl, ##STR00180## can each be independently substituted by F or Cl; R.sub.S2 represents anchoring group: ##STR00181## p represents 1 or 2, when p represents 2, -Sp.sup.d-X.sub.2 can be the same or different; o represents 0 or 1; X.sub.1 and X.sub.2 each independently represents H, OH, SH, NH.sub.2, NHR.sup.11, NR.sup.11.sub.2, NHC(O)R.sup.11, OR.sup.11, C(O)OH, CHO or C.sub.1-12 linear or branched, halogenated or unhalogenated alkyl; wherein, at least one of X.sub.1 and X.sub.2 is selected from OH, SH, NH.sub.2, NHR.sup.11, C(O)OH or CHO; Sp.sup.a, Sp.sup.c and Sp.sup.d each independently represents spacer group or single bond; Sp.sup.b each independently represents ##STR00182## ring ##STR00183## and ring ##STR00184## each independently represents ##STR00185## wherein one or more CH.sub.2 in ##STR00186## can be replaced by O, and one or more single bond in the ring can be replaced by double bond; Ls each independently represents F, Cl, CN, NO.sub.2, NCO, NCS, OCN, SCN, C(O)N(R.sup.O).sub.2, C(O)R.sup.0, C.sub.1-12 linear or branched alkyl, ##STR00187## wherein one or more than two 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, COO or OCO, and one or more H on the C.sub.1-12 linear or branched alkyl, ##STR00188## can each be independently substituted by F; R.sup.0 and R.sup.11 each independently represents C.sub.1-12 linear or branched alkyl; P represents polymerizable group; Sp represents spacer group or single bond; n.sub.s1 represents 0 or 1; n.sub.s2 represents 0, 1, 2 or 3, when n.sub.s2 represents 2 or 3, ##STR00189## can be the same or different; p.sub.s1, p.sub.s2, p.sub.s3 and p.sub.s4 each independently represents 0, 1 or 2, wherein 1?p.sub.s1+p.sub.s2?2; p.sub.s5 and p.sub.s6 each independently represents 0 or 1; and Z.sup.1 and Z.sup.2 each independently represents O, S, CO, COO, OCO, OCOO, CH.sub.2O, OCH.sub.2, CH.sub.2S, SCH.sub.2, CF.sub.2O, OCF.sub.2, CF.sub.2S, SCF.sub.2, (CH.sub.2).sub.n, CF.sub.2CH.sub.2, CH.sub.2CF.sub.2, (CF.sub.2).sub.n, CH?CH, CF?CF, CH?CF, CF?CH, C?C, CH?CHCOO, OCOCH?CH, CH.sub.2CH.sub.2COO, OCOCH.sub.2CH.sub.2, CR.sup.1R.sup.2 or single bond, wherein, R.sup.1 and R.sup.2 each independently represents H or C.sub.1-12 linear or branched alkyl, and n represents an integer of 1-4.

9. The liquid crystal composition according to claim 1, wherein the liquid crystal composition further comprises at least one additive.

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

Description

DETAILED EMBODIMENTS

[0185] 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.

[0186] For the convenience of the expression, the group structures of each compound in the following Examples are represented by the codes listed in Table 1:

TABLE-US-00001 TABLE 1 Codes of the group structures of the compounds Unit structure of group Code Name of group [00111] C 1,4-cyclohexylidene [00112] P 1,4-phenylene [00113] G 3-fluoro-1,4-phenylene [00114] G 2-fluoro-1,4-phenylene [00115] W 2,3-difluoro-1,4-phenylene [00116] THF tetrahydrofuran-2-yl [00117] THF(3) tetrahydrofuran-3-yl [00118] THT tetrahydrothiophene-2-yl [00119] DHT(1) 4,5-dihydrothiophene-2-yl [00120] C(5) cyclopentyl [00121] B(O) 4,6-difluoro-dibenzo[b,d] furan-3,7-diyl [00122] B(S) 4,6-difluoro-dibenzo[b,d] thiophene-3,7-diyl O O oxygen bridge group CH?CH or V ethenyl CH?CH.sub.2 CH.sub.2O 1O methyleneoxy C.sub.nH.sub.2n+1 or n (n alkyl or alkylene C.sub.nH.sub.2n represents an integer of 1-12)

[0187] Take the compound with following structural formula as an example:

##STR00123##

[0188] 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.

[0189] The abbreviated codes of the test items in the following Examples are as follows: [0190] Cp clearing point (nematic-isotropic phases transition temperature, ? C.) [0191] ?n optical anisotropy (589 nm, 25? C.) [0192] ?? dielectric anisotropy (1 KHz, 25? C.) [0193] ?.sub.1 rotational viscosity (mPa.Math.s, 25? C.) [0194] K.sub.11 splay elastic constant (25? C.) [0195] K.sub.33 bend elastic constant (25? C.) [0196] t.sub.?20? C. low-temperature storage time at ?20? C. (day) [0197] Ra roughness (nm) [0198] PTA pre-tilt angle (?, 25? C.) [0199] ?PTA stability of pre-tilt angle (change in pre-tilt angle after applying voltage for a fixed time, ?) [0200] VHR voltage holding ratio (%) [0201] in which, [0202] Cp: measured with melting point apparatus. [0203] ?n: measured with an Abbe refractometer under sodium lamp (589 nm) light source at 25? C. [0204] ??=?.sub.//???, in which, ?.sub.// is the dielectric constant parallel to the molecular axis, ?.sub.? is the dielectric constant perpendicular to the molecular axis, the test conditions: 25? C., 1 KHz and VA type test cell (cell gap 6 ?m). [0205] ?1: measured using a LCM-2 type liquid crystal physical property evaluation system; the test conditions: 25? C., 160 V-260 V, a test cell having a cell gap of 20 ?m. [0206] K.sub.11 and K.sub.33: calculated from the measured C-V curve of the liquid crystal material using LCR meter and a VA type test cell, the test conditions: a VA type test cell of 6 ?m, V=0.1?20 V. [0207] t.sub.?20?C.: placing the nematic liquid crystal media in glass vials, storing at ?20? C., and recording the time when crystal precipitation is observed. [0208] Ra: after UV photopolymerization of the polymerizable compound contained in the liquid crystal composition, the liquid crystal molecules are rinsed and then the morphological roughness of the polymerized polymer layer is tested with an atomic force microscope (AFM). [0209] PTA: measured by crystal rotation method. Liquid crystals are filled into VA type test cell (cell gap 3.5 ?m), and irradiated with ultraviolet light as described in UV1 step with the application of a voltage (15 V, 60 Hz), causing polymerization of the polymerizable compound and generation of pre-tilt angle PTA1, the liquid crystal composition with the generated pre-tilt angle PTA1 are subsequently irradiated with ultraviolet light as described in UV2 step to remove residual polymerizable compounds in the PTA1 state, and at this time the pre-tilt angle formed by the polymerizable compound is PTA2. In the present invention, the polymerization rate of polymerizable compound is investigated through the comparation of the pre-tilt angles formed after the same exposure time of UV1 irradiation (the smaller the pre-tilt angle, the faster the polymerization rate) or the times for forming the same pre-tilt angle (the shorter the time required for forming the same pre-tilt angle, the fast the polymerization rate). [0210] ?PTA: after the test cell used in the measurement of PTA is subjected to UV1 and UV2 steps to form a pre-tilt angle of 88?0.2?, 60 Hz SW wave, AC voltage (20 V) and DC voltage (2 V) are applied to the test cell at 40? C. with the presence of backlight. After a fixed time period, the pre-tilt angle of the test cell is tested, and ?PTA (168 h)=PTA (initial)?PTA (168 h), the smaller the ?PTA (168 h), the better the stability of the pre-tilt angle. [0211] Polymer residue: after applying UV2 for 70 minutes, the liquid crystal eluted from the liquid crystal test cell is detected by high-performance liquid chromatography (HPLC), and the content of polymerizable compounds therein is called polymer residue. [0212] VHR: measured using a TOYO6254 type liquid crystal physical property evaluation system after the application of UV2 for 70 minutes; the test conditions: 60? C., 5 V, 6 Hz, VA type test cell with a cell gap of 3.5 ?m.

[0213] The components used in the following Examples can either be synthesized by method known in the art or be obtained commercially. These synthetic techniques are conventional, and each of the obtained liquid crystal compounds is tested to meet the standards of electronic compound.

[0214] The liquid crystal compositions are prepared in accordance with the ratios specified in the following Examples. The preparation of the liquid crystal compositions is proceeded by mixing in accordance with the ratios through conventional methods in the art, such as heating, ultrasonic wave, suspension and the like.

[0215] The structures of the polymerizable compounds used in each of the following Examples are shown in Table 2 below.

TABLE-US-00002 TABLE 2 Structure and code for polymerizable compounds Component number structural formula Formula code RM-01 [00124] RM-02 [00125] RM-03 [00126] RM-1 [00127] I-2 RM-2 [00128] I-1 RM-3 [00129] I-4 RM-4 [00130] I-8

COMPARATIVE EXAMPLES 1-4 AND EXAMPLES 1-5

[0216] The liquid crystal compositions Comparative Host-1, Host-1 and Host-2 are prepared according to each compound and weight percentage listed in Table 3 and are tested by filling the same between two substrates of a liquid crystal display device.

TABLE-US-00003 TABLE 3 Formulation and test results for performance parameters of liquid crystal composition Weight percentage Component Comparative code Formula code Host-1 Host-1 Host-2 3CC2 M-1 20 20 20 3PP1 M-6 9 9 9 3CPO2 M-2 1 1 1 4CC3 M-1 7.5 7.5 7.5 2C1OWO2 N-3 2 2 2 3C1OWO2 N-3 11.5 11.5 11.5 3CCP1 M-12 8 8 8 2CPWO2 N-13 8.5 8.5 8.5 3CPWO2 N-13 9.5 9.5 9.5 3CPWO3 N-13 6 6 6 3CC1OWO2 N-6 14 14 14 5OB(O)O2 B-1 3 C(5)1OB(O)O4 II-3 3 THF1OB(S)O4 II-4 3 Total 100 100 100 Cp 75.9 76.2 76.5 ?n 0.101 0.102 0.103 ?? ?3.3 ?3.5 ?3.6 K.sub.11 15 15.2 15.4 K.sub.33 13.9 14.3 14.7 ?.sub.1 81 78 78

[0217] Polymerizable compounds RM-01, RM-02, RM-03 and RM-1 are added into 100 parts by weight of the liquid crystal composition Comparative Host-1 respectively to form the compositions of Comparative Examples 1-3, and polymerizable compound RM-01 is added into 100 parts by weight of the liquid crystal composition Host-1 to form the composition of Comparative Example 4, polymerizable compounds RM-1 and RM-2 are added into 100 parts by weight of the liquid crystal composition Host-1 respectively to form the compositions of Examples 1-2, and polymerizable compounds RM-1, RM-2, RM-3 and RM-4 are added into 100 parts by weight of the liquid crystal composition Host-2 respectively to form the compositions of Examples 3-5. The specific parts by weight of the polymerizable compounds and the test results of the relevant performances are shown as follows in Table 4.

TABLE-US-00004 TABLE 4 Specific parts by weight of the polymerizable compounds and the test results of the relevant performances Comparative Comparative Comparative Comparative Example 1 Example 2 Example 3 Example 4 Types and RM-01 0.3 0.3 contents of RM-02 0.28 polymerizable RM-03 0.2 compounds RM-1 0.3 RM-2 RM-3 RM-4 Ra (nm) 15.8 14.7 13.6 14.8 t.sub.?20? C. (day) <15 <15 <16 <18 PTA1 (?) 60 s formed after 70 s 89.02 UV1 step for 80 s 89.52 89.44 88.26 89.03 different 90 s 88.89 88.86 87.38 88.47 100 s 87.94 87.88 87.34 Residual content of 185 171 96 147 polymer after UV2 step Pre-tilt angle PTA 88.02 88.06 88.05 88.01 stability test PTA 87.89 87.88 87.9 87.9 (?) PTA 87.81 87.76 87.78 87.81 PTA 87.69 87.65 87.69 87.72 PTA 87.62 87.63 87.66 87.66 PTA 87.6 87.62 87.63 87.62 ?PTA 0.42 0.44 0.42 0.39 VHR (%) after UV2 93.8 93.5 93.9 94 Example Example Example Example Example 1 2 3 4 5 Types and RM-01 contents of RM-02 polymerizable RM-03 compounds RM-1 0.3 0.3 RM-2 0.3 0.3 RM-3 0.28 RM-4 0.02 Ra (nm) 12.7 12.4 12.5 12.6 12.3 t.sub.?20? C. (day) >20 >20 >20 >20 >20 PTA1 (?) 60 s 89.05 89.45 89.33 89.26 89.42 formed after 70 s 88.35 88.39 88.05 88.56 88.27 UV1 step for 80 s 87.03 87.26 87.11 87.33 87.24 different 90 s 100 s Residual content of 45 43 45 43 42 polymer after UV2 step Pre-tilt angle PTA 88.03 88.01 88.03 88.04 88.01 stability test PTA 87.91 87.88 87.94 87.95 87.92 (?) PTA 87.82 87.82 87.86 87.87 87.83 PTA 87.74 87.77 87.78 87.8 87.75 PTA 87.68 87.71 87.77 87.74 87.71 PTA 87.68 87.69 87.77 87.72 87.7 ?PTA 0.35 0.32 0.33 0.32 0.31 VHR (%) after UV2 94.3 94.6 94.8 94.6 94.7

[0218] It can be seen from the comparisons between Comparative Examples 1-4 and Examples 1-5 that, the liquid crystal compositions of the present invention have a larger absolute value of dielectric anisotropy, a larger K value, a longer low-temperature storage time period and a lower polymer layer surface roughness, a smaller pre-tilt angle formed within a relatively short time period and a faster speed for forming pre-tilt angle under the action of UV1, a lower polymer residue after UV2 step for 70 min, a higher VHR and a better pre-tilt angle stability, while maintaining appropriate clearing point, optical anisotropy and rotational viscosity.

COMPARATIVE EXAMPLES 5-8 AND EXAMPLES 6-10

[0219] The liquid crystal compositions Comparative Host-2, Host-3 and Host-4 are prepared according to each compound and weight percentage listed in Table 5 and are tested by filling the same between two substrates of a liquid crystal display device.

TABLE-US-00005 TABLE 5 Formulation and test results for performance parameters of liquid crystal composition Weight percentage Comparative Component code Formula code Host-2 Host-3 Host-4 1PWO2 N-10 7.5 7.5 7.5 3CCV1 M-1 8 8 8 2PWO2 N-10 8 8 8 3CPO2 M-2 4.5 4.5 4.5 4CC3 M-1 8 8 8 4CCV1 M-1 15.5 15.5 15.5 3PWO2 N-10 8 8 8 5CC3 M-1 7.5 7.5 7.5 3CCP1 M-12 9 9 9 5OB(O)O2 B-1 4 3OB(O)O4 B-1 5 THT1OB(O)O4 II-4 4 THT1OB(O)O6 II-4 5 DHT(1)1OB(O)O4 II-10 4 THF(3)1OB(O)O6 II-5 5 3CPWO2 N-13 8 8 8 3CCWO2 N-13 7 7 7 Total 100 100 100 Cp 75.4 76.9 77.3 ?n 0.11 0.112 0.113 ?? ?3.3 ?3.5 ?3.6 K.sub.11 14.8 15.2 15.5 K.sub.33 15.4 16.5 16.7 ?.sub.1 86 87 89

[0220] Polymerizable compounds RM-01, RM-02, RM-03 and RM-1 are added into 100 parts by weight of liquid crystal composition Comparative Host-2 respectively to form the compositions of Comparative Examples 5-7, and polymerizable compound RM-01 is added into 100 parts by weight of liquid crystal composition Host-3 to form the composition of Comparative Example 8, polymerizable compounds RM-1 and RM-2 are added into 100 parts by weight of liquid crystal composition Host-3 respectively to form the compositions of Examples 6-7, and polymerizable compounds RM-1, RM-2, RM-3 and RM-4 are added into 100 parts by weight of liquid crystal composition Host-4 respectively to form the compositions of Examples 8-10. The specific parts by weight of the polymerizable compounds and the test results of the relevant performances are shown as follows in Table 6.

TABLE-US-00006 TABLE 6 Specific parts by weight of the polymerizable compounds and the test results of the relevant performances Comparative Comparative Comparative Comparative Example 5 Example 6 Example 7 Example 8 Types and RM-01 0.3 0.3 contents of RM-02 0.28 polymerizable RM-03 0.2 compounds RM-1 0.3 RM-2 RM-3 RM-4 Ra (nm) 15.3 15.5 13.8 14.2 t.sub.?20? C. (day) <15 <15 <16 <19 PTA1 (?) 50 s formed after 60 s UV1 step for 70 s 89.31 different 80 s 89.59 89.63 88.62 89.13 90 s 88.73 88.79 87.53 88.21 100 s 87.84 87.93 87.29 Residual content of 160 153 93 152 polymer after UV2 step Pre-tilt angle PTA 88.03 88.06 88.03 88.01 stability test PTA 87.89 87.91 87.81 87.89 (?) PTA 87.78 87.8 87.74 87.8 PTA 87.69 87.72 87.68 87.71 PTA 87.64 87.65 87.63 87.66 PTA 87.6 87.65 87.6 87.62 ?PTA 0.43 0.41 0.43 0.39 VHR (%) after UV2 93.1 93.4 93.5 93.7 Example Example Example Example Example 6 7 8 9 10 Types and RM-01 contents of RM-02 polymerizable RM-03 compounds RM-1 0.3 0.3 RM-2 0.3 0.3 RM-3 0.28 RM-4 0.02 Ra (nm) 12.7 12.2 12.3 12.2 12.1 t.sub.?20? C. (day) >20 >20 >20 >20 >20 PTA1 (?) 50 s 89.57 89.61 89.06 89.63 89.41 formed after 60 s 88.75 88.38 88.11 88.89 88.83 UV1 step for 70 s 87.18 87.06 86.93 87.17 87.16 different 80 s 90 s 100 s Residual content of 49 50 49 51 52 polymer after UV2 step Pre-tilt angle PTA 87.98 87.95 87.98 88.01 87.97 stability test PTA 87.88 87.88 87.89 87.93 87.89 (?) PTA 87.8 87.8 87.83 87.84 87.8 PTA 87.74 87.75 87.76 87.76 87.71 PTA 87.7 87.7 87.7 87.7 87.66 PTA 87.66 87.7 87.65 87.67 87.62 ?PTA 0.32 0.35 0.33 0.34 0.35 VHR (%) after UV2 94.1 94 94.2 94 94.1

[0221] It can be seen from the comparisons between Comparative Examples 5-8 and Examples 6-10 that, the liquid crystal compositions of the present invention have a larger absolute value of dielectric anisotropy, a larger K value, a longer low-temperature storage time period and a lower polymer layer surface roughness, a smaller pre-tilt angle formed within a relatively short time period and a faster speed for forming pre-tilt angle under the action of UV1, a lower polymer residue after UV2 step for 70 min, a higher VHR and a better pre-tilt angle stability, while maintaining appropriate clearing point, optical anisotropy and rotational viscosity.

EXAMPLE 11

0.6 Part by Weight of Compound SA-2-1

[0222] ##STR00131## [0223] is added into 100 parts by weight of Host-1, and 0.6 part by weight of polymerizable compound RM-1 is added. The resulted liquid crystal composition is filled into unaligned test cell (having a cell thickness d of 3.5 ?m, ITO coating on both sides (being structured ITO in the case of multi-domain switching), no alignment layer and no passivation layer).

[0224] The liquid crystal display forms a spontaneous vertical alignment relative to the surface of the substrate, and the orientation is stable until the clearing point is reached and the resulting VA cell can be inversely switched. A cross polarizer is required to display the switch.

[0225] By using additives such as the compound of formula SA-2-1, and based on the combination of ??<0 and vertical alignment, VA, PM-VA, PVA, MVA, HT-VA, VA-IPS and other similar display technologies eliminate the need for alignment layers (e.g., no PI coating).

EXAMPLE 12

0.6 Part by Weight of Compound SA-4-1

[0226] ##STR00132## [0227] is added into 100 parts by weight of Host-2, and 0.6 part by weight of polymerizable compound RM-2 is added. The resulted liquid crystal composition is filled into unaligned test cell (having a cell thickness d of 3.5 ?m, ITO coating on both sides (being structured ITO in the case of multi-domain switching), no alignment layer and no passivation layer).

[0228] The liquid crystal display forms a spontaneous vertical alignment relative to the surface of the substrate, and the orientation is stable until the clearing point is reached and the resulting VA cell can be inversely switched. A cross polarizer is required to display the switch.

[0229] By using additives such as the compound of formula SA-4-1, and based on the combination of ??<0 and vertical alignment, VA, PM-VA, PVA, MVA, HT-VA, VA-IPS and other similar display technologies eliminate the need for alignment layers (e.g., no PI coating).

EXAMPLE 13

0.5 Part by Weight of Compound SA-4-2

[0230] ##STR00133## [0231] is added into 100 parts by weight of Host-3, and 0.5 part by weight of polymerizable compound RM-3 is added. The resulted liquid crystal composition is filled into unaligned test cell (having a cell thickness d of 3.5 ?m, ITO coating on both sides (being structured ITO in the case of multi-domain switching), no alignment layer and no passivation layer).

[0232] The liquid crystal display forms a spontaneous vertical alignment relative to the surface of the substrate, and the orientation is stable until the clearing point is reached and the resulting VA cell can be inversely switched. A cross polarizer is required to display the switch.

[0233] By using additives such as the compound of formula SA-4-2, and based on the combination of ??<0 and vertical alignment, VA, PM-VA, PVA, MVA, HT-VA, VA-IPS and other similar display technologies eliminate the need for alignment layers (e.g., no PI coating).

[0234] In conclusion, the liquid crystal composition of the present invention has a relatively large absolute value of dielectric anisotropy, a relatively large K value, a relatively long low-temperature storage time period, a relatively low polymer layer surface roughness, a relatively small pre-tilt angle, a relatively fast speed for forming pre-tilt angle, a relatively low polymer residue, a relatively high VHR and a relatively good pre-tilt angle stability, while maintaining appropriate clearing points, optical anisotropy and rotational viscosity, such that the liquid crystal display device containing the liquid crystal composition has a relatively wide temperature usage range, relatively good contrast, and relatively good low-temperature mutual solubility; in addition, the production process of PSA-type liquid crystal displays can be effectively sped up, production efficiency is improved, and at the same time, the problems of image sticking, uneven display and broken bright spots present in existing PSA type liquid crystal displays is effectively improved, and the present invention has a relatively high practical application value.

[0235] The above embodiments are merely illustrative of the technical concepts and the features of the present invention, are included merely for purposes of illustration and implement of the present invention, and are not intended to limit the scope of the present invention. Equivalent variations or modifications are intended to be included within the scope of the present invention.

INDUSTRIAL APPLICABILITY

[0236] The liquid crystal composition involved in the present invention can be applied to the field of liquid crystal.