LIQUID CRYSTAL COMPOSITION AND LIQUID CRYSTAL DISPLAY ELEMENT

Abstract

The present invention belongs to the technical field of liquid crystal materials, and in particular relates to a liquid crystal composition and a liquid crystal display element or liquid crystal display containing the liquid crystal composition. The liquid crystal composition of the present invention is characterized in that the liquid crystal composition comprises more than or equal to 30% of a compound represented by Formula I, and also comprises one or more compounds represented by Formula II and one or more compounds represented by Formula III. The liquid crystal composition of the present invention has a high refractive index, a high clearing point and also a low rotational viscosity, and is mainly used for the display of a projector with a relatively high working temperature and a low cell thickness.

##STR00001##

Claims

1. A liquid crystal composition, comprising more than or equal to 30% by mass of a compound represented by Formula I, and one or more compounds represented by Formula II, and one or more compounds represented by Formula III: ##STR00050## wherein in Formula II, R.sub.1O and OR.sub.2 each independently represent an alkoxy with a carbon atom number of 1-10, a fluoro-substituted alkoxy with a carbon atom number of 1-10, an alkenoxy with a carbon atom number of 2-10, or a fluoro-substituted alkenoxy with a carbon atom number of 2-10; in Formula III, R.sub.3 and R.sub.4 each independently represent an alkyl with a carbon atom number of 1-10, a fluoro-substituted alkyl with a carbon atom number of 1-10, an alkoxy with a carbon atom number of 1-10, a fluoro-substituted alkoxy with a carbon atom number of 1-10, an alkenyl with a carbon atom number of 2-10, a fluoro-substituted alkenyl with a carbon atom number of 2-10, an alkenoxy with a carbon atom number of 3-8, or a fluoro-substituted alkenoxy with a carbon atom number of 3-8.

2. The liquid crystal composition according to claim 1, wherein the liquid crystal composition further comprises one or more compounds represented by Formula IV: ##STR00051## wherein in Formula IV, R.sub.5 represents an alkyl with a carbon atom number of 1-10 or an alkenyl with a carbon atom number of 2-10; OR.sub.6 represents an alkoxy with a carbon atom number of 1-10 or an alkenoxy with a carbon atom number of 2-10; and ##STR00052## represents ##STR00053##

3. The liquid crystal composition according to claim 1, wherein the liquid crystal composition further comprises one or more compounds represented by Formula V: ##STR00054## wherein in Formula V, R.sub.7 represents an alkyl with a carbon atom number of 1-10 or an alkenyl with a carbon atom number of 2-10; OR.sub.8 represents an alkoxy with a carbon atom number of 1-10 or an alkenoxy with a carbon atom number of 2-10; and ##STR00055## each independently represent ##STR00056##

4. The liquid crystal composition according to claim 1, wherein the liquid crystal composition further comprises one or more compounds represented by Formulas VI-A, VI-B, VI-C, VI-D, VI-E, VI-F, and VI-G: ##STR00057##

5. The liquid crystal composition according to claim 1, wherein the liquid crystal composition further comprises one or more compounds represented by Formula VII: ##STR00058## wherein in Formula VII, R.sub.9 and R.sub.10 each independently represent an alkyl with a carbon atom number of 1-10, an alkoxy with a carbon atom number of 1-10 or an alkenyl with a carbon atom number of 2-10; and ##STR00059## represents ##STR00060##

6. The liquid crystal composition according to claim 1, wherein the liquid crystal composition comprises one or more compounds represented by Formula VIII: ##STR00061## wherein in Formula VIII, R.sub.11 and R.sub.12 represent an alkyl with a carbon atom number of 1-10, a fluoro-substituted alkyl with a carbon atom number of 1-10, an alkoxy with a carbon atom number of 1-10, a fluoro-substituted alkoxy with a carbon atom number of 1-10, an alkenyl with a carbon atom number of 2-10, a fluoro-substituted alkenyl with a carbon atom number of 2-10, an alkenoxy with a carbon atom number of 3-8, or a fluoro-substituted alkenoxy with a carbon atom number of 3-8, and one or more nonadjacent —CH.sub.2— in the group can be replaced by cyclopentylene or cyclopropylene; and X represents O or S.

7. The liquid crystal composition according to claim 1, wherein the mass content of the compound represented by Formula II is 1-20%, preferably 5-10%; and the mass percentage content of the compound represented by Formula III is 1-20%, preferably 3-15%.

8. The liquid crystal composition according to claim 2, characterized in that wherein the mass content of the compound represented by Formula IV is 1-15%.

9. The liquid crystal composition according to claim 3, characterized in that wherein the mass content of the compound shown in the formula V is 20-50%.

10. The liquid crystal composition according to claim 4, characterized in that wherein the mass content of the compound shown in the formula VI is 3-8%.

11. The liquid crystal composition according to claim 5, characterized in that wherein the mass content of the compound represented by Formula VII is 5-10%.

12. The liquid crystal composition according to claim 6, wherein the mass content of the compound shown in the formula VIII is 3-10%.

13. A liquid crystal display element or liquid crystal display, wherein the liquid crystal display element or liquid crystal display comprises the liquid crystal composition according to claim 1, and the liquid crystal display element or liquid crystal display is an active matrix display element or a passive matrix display element.

Description

DETAILED DESCRIPTION OF EMBODIMENTS

[0013] The present invention provides a liquid crystal composition, the liquid crystal composition comprising more than or equal to 30% by mass of a compound represented by Formula I, and one or more compounds represented by Formula II, and one or more compounds represented by Formula III:

##STR00003##

[0014] wherein in Formula II,

[0015] R.sub.1O and OR.sub.2 each independently represent an alkoxy with a carbon atom number of 1-10, a fluoro-substituted alkoxy with a carbon atom number of 1-10, an alkenoxy with a carbon atom number of 2-10, or a fluoro-substituted alkenoxy with a carbon atom number of 2-10;

[0016] in Formula III,

[0017] R.sub.3 and R.sub.4 each independently represent an alkyl with a carbon atom number of 1-10, a fluoro-substituted alkyl with a carbon atom number of 1-10, an alkoxy with a carbon atom number of 1-10, a fluoro-substituted alkoxy with a carbon atom number of 1-10, an alkenyl with a carbon atom number of 2-10, a fluoro-substituted alkenyl with a carbon atom number of 2-10, an alkenoxy with a carbon atom number of 3-8, or a fluoro-substituted alkenoxy with a carbon atom number of 3-8.

[0018] As for the liquid crystal composition of the present invention, preferably, the compound represented by Formula II in the above-mentioned liquid crystal composition is selected from the group consisting of compounds represented by Formula II-A, II-B, II-C, II-D, II-E and II-F:

##STR00004##

[0019] As for the liquid crystal composition of the present invention, preferably, the mass content of the compound represented by Formula II in the above-mentioned liquid crystal composition is 1-20%, further preferably 5-10%.

[0020] As for the liquid crystal composition of the present invention, preferably, the compound represented by Formula III in the liquid crystal composition is selected from the group consisting of compounds represented by Formulas III-A, III-B, III-D and III-E:

##STR00005##

[0021] As for the liquid crystal composition of the present invention, preferably, the mass content of the compound represented by Formula III in the above-mentioned liquid crystal composition is 1-20%, further preferably 3-15%.

[0022] The liquid crystal composition of the present invention preferably further comprises one or more compounds represented by Formula IV:

##STR00006##

[0023] wherein in Formula IV,

[0024] R.sub.5 represents an alkyl with a carbon atom number of 1-10 or an alkenyl with a carbon atom number of 2-10; OR.sub.6 represents an alkoxy with a carbon atom number of 1-10 or an alkenoxy with a carbon atom number of 2-10; and

##STR00007##

represents

##STR00008##

[0025] As for the liquid crystal composition of the present invention, preferably, the above-mentioned compound represented by Formula IV is selected from the group consisting of compounds represented by Formula IV-A, IV-B, IV-C, IV-D, IV-E, IV-F and IV-G:

##STR00009##

[0026] As for the liquid crystal composition of the present invention, preferably, the mass content of the compound represented by Formula IV in the above-mentioned liquid crystal composition is 1-15%.

[0027] The liquid crystal composition of the present invention preferably further comprises one or more compounds represented by Formula V:

##STR00010##

[0028] wherein in Formula V,

[0029] R.sub.7 represents an alkyl with a carbon atom number of 1-10 or an alkenyl with a carbon atom number of 2-10; OR.sub.8 represents an alkoxy with a carbon atom number of 1-10 or an alkenoxy with a carbon atom number of 2-10; and

##STR00011##

each independently represent

##STR00012##

[0030] As for the liquid crystal composition of the present invention, preferably, the above-mentioned compound represented by Formula V is selected from the group consisting of compounds represented by Formulas V-A, V-B, V-C, V-D, V-E, V-F, V-G, V-H, V-J, V-K, V-L, and V-M:

##STR00013## ##STR00014##

[0031] As for the liquid crystal composition of the present invention, preferably, the mass content of the compound represented by Formula V in the above-mentioned liquid crystal composition is 1-55%, further preferably 20-50%.

[0032] As for the liquid crystal composition of the present invention, preferably, the above-mentioned liquid crystal composition further comprises one or more compounds represented by Formulas VI-A, VI-B, VI-C, VI-D, VI-E, VI-F and VI-G:

##STR00015##

[0033] As for the liquid crystal composition of the present invention, preferably, the mass content of the compound represented by Formula VI is 1-10%, further preferably 3-8%.

[0034] The liquid crystal composition of the present invention preferably further comprises one or more compounds represented by Formula VII:

##STR00016##

[0035] wherein in Formula VII,

[0036] R.sub.9 and R.sub.10 each independently represent an alkyl with a carbon atom number of 1-10, an alkoxy with a carbon atom number of 1-10 or an alkenyl with a carbon atom number of 2-10; and

##STR00017##

represents

##STR00018##

[0037] As for the liquid crystal composition of the present invention, preferably, the above-mentioned compound represented by Formula VII is selected from the group consisting of compounds represented by Formulas VII-A, VII-B, VII-C, VII-D, VII-E, VII-F, and VII-G:

##STR00019##

[0038] As for the liquid crystal composition of the present invention, preferably, the mass content of the compound represented by Formula VII is 1-15%, further preferably 5-10%.

[0039] The liquid crystal composition of the present invention preferably further comprises one or more compounds represented by Formula VIII:

##STR00020##

[0040] wherein in Formula VIII,

[0041] R.sub.11 and R.sub.12 represent an alkyl with a carbon atom number of 1-10, a fluoro-substituted alkyl with a carbon atom number of 1-10, an alkoxy with a carbon atom number of 1-10, a fluoro-substituted alkoxy with a carbon atom number of 1-10, an alkenyl with a carbon atom number of 2-10, a fluoro-substituted alkenyl with a carbon atom number of 2-10, an alkenoxy with a carbon atom number of 3-8, or a fluoro-substituted alkenoxy with a carbon atom number of 3-8, and one or more nonadjacent —CH.sub.2— in the group can be replaced by cyclopentylene or cyclopropylene; and

[0042] X represents O or S.

[0043] As for the liquid crystal composition of the present invention, preferably, the above-mentioned compound represented by Formula VIII is selected from the group consisting of compounds represented by the following Formulas VIII-A, VIII-B, VIII-C, VIII-D, VIII-E, VIII-F, VIII-G, and VIII-H:

##STR00021##

[0044] As for the liquid crystal composition of the present invention, preferably, the mass content of the compound represented by Formula VIII is 1-15%, further preferably 3-10%.

[0045] As for the liquid crystal composition of the present invention, preferably, various functional dopants may also be added to the above-mentioned liquid crystal composition.

[0046] As for the liquid crystal composition of the present invention, preferably, the above-mentioned dopants are mainly antioxidants, light stabilizers, etc.

[0047] As for the liquid crystal composition of the present invention, preferably, the added amount of the above-mentioned dopants is preferably between 0.01% and 1% of the mass of the above-mentioned liquid crystal composition.

[0048] [Liquid Crystal Display Element or Liquid Crystal Display]

[0049] The present invention further relates to a liquid crystal display element or liquid crystal display comprising any one of the above-mentioned liquid crystal compositions; and the display element or display is an active matrix display element or display.

[0050] The above-mentioned active matrix display element or display can be specifically exemplified by, for example, IPS-TFT or FFS-TFT or VA-TFT liquid crystal display elements or other TFT displays, especially liquid crystal display elements or liquid crystal displays in which FFS-TFT mode is applied.

[0051] The liquid crystal display element or liquid crystal display of the present invention comprises the liquid crystal composition disclosed in the present invention. The liquid crystal display element or liquid crystal display of the present invention is mainly used in the fields of projectors, vehicles, outdoor information display, etc.

EXAMPLES

[0052] In order to explain the present invention more clearly, the present invention will be further explained below in conjunction with preferred examples. A person skilled in the art should understand that the following detailed description is illustrative rather than restrictive, and should not limit the scope of protection of the present invention.

[0053] In the present invention, the preparation methods are all conventional methods unless otherwise specified, the raw materials used can all be obtained from open commercial channels unless otherwise specified, the percentages all refer to mass percentages, the temperatures are degrees Celsius (° C.), and the specific meanings and test conditions of the other symbols are as follows:

[0054] Tni represents the clearing point (° C.) of a liquid crystal, as measured by DSC quantitative method;

[0055] An represents optical anisotropy, with Δn=ne−no, wherein no is the refractive index of ordinary light and ne is the refractive index of extraordinary light, and the test conditions are 25±2° C. and 60±2° C., 589 nm, and Abbe refractometer test;

[0056] Δε represents dielectric anisotropy, Δε=ε.sub.//#−ε.sub.⊥, wherein ε.sub.// is the dielectric constant parallel to the molecular axis, and ε.sub.⊥ is the dielectric constant perpendicular to the molecular axis, and the test conditions are 25±0.5° C., 20 μm antiparallel cell, and INSTEC:ALCT-IR1 test;

[0057] γ.sub.1 represents rotational viscosity (mPa.Math.s), and the test conditions are 25° C.±0.5° C., 20 μm vertical cell, and INSTEC:ALCT-IR1 test;

[0058] The preparation method for the liquid crystal composition involves: weighing various liquid crystal monomers at a certain ratio and putting the liquid crystal monomers into a stainless steel beaker, placing the stainless steel beaker containing these liquid crystal monomers on a magnetic stirring instrument for heating and melting, adding a magnetic rotor to the stainless steel beaker when most of the liquid crystal monomers in the stainless steel beaker have melted, uniformly stirring the mixture, and cooling the mixture to room temperature to obtain the liquid crystal composition.

[0059] The structures of the liquid crystal monomers in the examples of the present invention are represented by codes, and the code representation method for liquid crystal ring structures, terminal groups and linker groups is shown in Tables 1 and 2 below.

TABLE-US-00001 TABLE 1 Corresponding codes of ring structures Ring structure Corresponding code [00022] C [00023] L [00024] P [00025] G [00026] Gi [00027] Y [00028] B [00029] Sb [00030] Sc

TABLE-US-00002 TABLE 2 Corresponding codes of terminal groups and linker groups Terminal groups and linker groups Corresponding code C.sub.nH.sub.2n+1— n- C.sub.nH.sub.2n+1O— nO— —CH.sub.2O— —O— —F —F —CH.sub.2CH.sub.2— —E— —CH═CH— —V— —COO— —COO— —CH═CH—C.sub.nH.sub.2n+1 —Vn [00031] Cp— [00032] CpO— [00033] Cpr— [00034] Cpr1—

[0060] For example:

##STR00035##

the code of which is CC-Cp-V1;

##STR00036##

the code of which is PPY-3-O2;

##STR00037##

the code of which is CPY-2-O2;

##STR00038##

the code of which is CCY-3-O2;

##STR00039##

the code of which is COY-3-O2;

##STR00040##

the code of which is CCOY-3-O2;

##STR00041##

the code of which is CLY-3-O2;

##STR00042##

the code of which is Sb-CpO-04;

##STR00043##

the code of which is Sc-CpO-04;

##STR00044##

the code of which is PGP-Cpr1-2;

##STR00045##

the code of which is B-2O-O4;

##STR00046##

the code of which is B-CpO-O4;

##STR00047##

the code of which is CY-3-O2;

##STR00048##

the code of which is PP-1-2V;

##STR00049##

the code of which is PGP-5-2.

[0061] The following specific examples are used to illustrate the present invention:

EXAMPLES

Example 1

[0062] The formula and corresponding properties of the liquid crystal compositions were as shown in Table 3 below.

TABLE-US-00003 TABLE 3 Formula and corresponding properties of the liquid crystal composition of Example 1 Code of liquid Class crystal monomer Content (%) I CC-3-V 35 II B-2O-O5 5 III PGP-2-2V1 13 IV PY-3-O2 5 V CPY-3-O2 10 V CPY-2-O2 10 V PGiY-3-O2 5 V PPY-3-O2 2 VI-C PYP-2-3 5 VII CCP-V-1 5 VIII Sc-2O-O4 5 Properties Tni: 92.4° C. Δn (25° C.): 0.147 Δε: −3.0 γ.sub.1: 83 mPa .Math. s

Example 2

[0063] The formula and corresponding properties of the liquid crystal compositions were as shown in Table 4 below.

TABLE-US-00004 TABLE 4 Formula and corresponding properties of the liquid crystal composition of Example 2 Code of liquid Class crystal monomer Content (%) I CC-3-V 33 II B-2O-O5 5 II B-2O-O6 5 III PGP-2-2V 8 IV PY-3-O2 5 V CPY-3-O2 10 V CPY-2-O2 5 V CPY-1-O2 10 V PGiY-3-O2 5 V PPY-3-O2 2 V PPY-5-O2 2 VI-C PYP-2-3 5 VIII Sc-2O-O4 5 Properties Tni: 92.7° C. Δn (25° C.): 0.151 Δε: −4.0 γ.sub.1: 111 mPa .Math. s

Example 3

[0064] The formula and corresponding properties of the liquid crystal compositions were as shown in Table 5 below.

TABLE-US-00005 TABLE 5 Formula and corresponding properties of the liquid crystal composition of Example 3 Code of liquid Class crystal monomer Content (%) I CC-3-V 30 II B-2O-O4 5 II B-2O-O5 5 III PGP-1-2V 5 IV PY-3-O2 5 V CPY-2-O2 6 V CPY-3-O2 10 V CPY-1-O2 10 V PGiY-3-O2 5 V PPY-3-O2 2 V PPY-5-O2 2 VI-D PYP-4-2 5 VIII Se-2O-O5 10 Properties Tni: 93.3° C. Δn (25° C.): 0.156 Δε: −5.0 γ.sub.1: 126 mPa .Math. s

Example 4

[0065] The formula and corresponding properties of the liquid crystal compositions were as shown in Table 6 below.

TABLE-US-00006 TABLE 6 Formula and corresponding properties of the liquid crystal composition of Example 4 Code of liquid Class crystal monomer Content (%) I CC-3-V 31 II B-2O-O5 3 III PGP-3-2 5 V CPY-3-O2 10 V CPY-1-O2 10 V CLY-3-O2 10 V CLY-4-O2 6 V PGiY-3-O2 3 V PGiY-2-O4 3 V PPY-3-O2 2 V PPY-5-O2 2 V PPY-3-O4 2 VI-C PYP-2-3 3 VII CLP-V-1 5 VII CPP-3-2V1 5 Properties Tni: 122.3° C. Δn (25° C.): 0.147 Δε: −3.1 γ.sub.1: 152 mPa .Math. s

Example 5

[0066] The formula and corresponding properties of the liquid crystal compositions were as shown in Table 7 below.

TABLE-US-00007 TABLE 7 Formula and corresponding properties of the liquid crystal composition of Example 5 Code of liquid Class crystal monomer Content (%) I CC-3-V 30 II B-2O-O6 5 III PGP-3-V1 5 V CCY-3-O2 5 V CPY-3-O2 10 V CPY-2-O2 6 V CPY-1-O2 10 V CLY-3-O2 10 V CLY-4-O2 5 V PPY-3-O2 2 V PPY-5-O2 2 V PPY-3-O4 2 VIII Sb-2O-O4 8 Properties Tni: 119.4° C. Δn (25° C.): 0.148 Δε: −4.8 γ.sub.1: 169 mPa .Math. s

Example 6

[0067] The formula and corresponding properties of the liquid crystal compositions were as shown in Table 8 below.

TABLE-US-00008 TABLE 8 Formula and corresponding properties of the liquid crystal composition of Example 6 Code of liquid Class crystal monomer Content (%) I CC-3-V 30 II B-3O-O2 8 II B-3O-O3 4 III PGP-2-2V 12 IV CY-5-O2 4 V CPY-3-O2 10 V CPY-2-o2 10 VI PYP-2-3 12 VII CCP-V-1 10 Properties Tni: 91° C. Δn (25° C.): 0.142 Δn (60° C.): 0.132 Δε: −3.2 γ.sub.1: 84 mPa .Math. s

Example 7

[0068] The formula and corresponding properties of the liquid crystal compositions were as shown in Table 9 below.

TABLE-US-00009 TABLE 9 Formula and corresponding properties of the liquid crystal composition of Example 7 Code of liquid Class crystal monomer Content (%) I CC-3-V 35 II B-2O-O5 5 III PGP-2-2V1 5 III PGP-2-2V 8 IV PY-3-O2 5 V CPY-3-O2 10 V CPY-2-O2 10 V PGiY-3-O2 5 V PPY-3-O2 2 VI-C PYP-2-3 5 VII CCP-V-1 5 VIII Se-2O-O4 5 Properties Tni: 92.1° C. Δn (25° C.): 0.147 Δε: −3.0 γ.sub.1: 79 mPa .Math. s

Example 8

[0069] The formula and corresponding properties of the liquid crystal compositions were as shown in Table 10 below.

TABLE-US-00010 TABLE 10 Formula and corresponding properties of the liquid crystal composition of Example 8 Code of liquid Class crystal monomer Content (%) I CC-3-V 33 II B-2O-O5 5 II B-2O-O6 5 III PGP-2-2V 8 IV PY-3-O2 5 V CPY-3-O2 10 V CPY-2-O2 5 V CPY-1-O2 10 V PPY-3-O2 3 V PPY-3-O4 3 V PPY-5-O2 3 VI-C PYP-2-3 5 VIII Se-2O-O4 5 Properties Tni: 92.7° C. Δn (25° C.): 0.150 Δε: −3.9 γ.sub.1: 110 mPa .Math. s

Example 9

[0070] The formula and corresponding properties of the liquid crystal compositions were as shown in Table 11 below.

TABLE-US-00011 TABLE 11 Formula and corresponding properties of the liquid crystalc omposition of Example 9 Code of liquid Class crystal monomer Content (%) I CC-3-V 31 II B-20-05 3 III PGP-1-2V 5 V CPY-3-02 10 V CPY-1-02 10 V CLY-3-02 10 V CLY-4-02 6 V PGiY-3-02 3 V PGiY-2-04 3 V PPY-3-02 2 V PPY-5-02 2 V PPY-3-04 2 VI-C PYP-2-3 3 VII CLP-V-1 5 VII CPP-3-2V1 5 Properties Tni: 122° C. Δn (25° C.): 0.148 Δε: −3.1 γ.sub.1: 149 mPa .Math. s

Comparative Example 1

[0071] The formula and corresponding properties of the liquid crystal compositions were as shown in Table 12 below.

TABLE-US-00012 TABLE 12 Formula and corresponding properties of the liquid crystal composition of Comparative Example 1 Code of liquid Class crystal monomer Content (%) I CC-3-V 35 II B-2O-O5 5 IV PY-3-O2 5 V CPY-3-O2 10 V CPY-2-O2 10 V PGiY-3-O2 5 V PPY-3-O2 2 VI-C PYP-2-3 5 VII CCP-V-1 5 VIII Sc-2O-O4 5 CCP-V2-1 10 PP-5-1 3 Properties Tni: 89.1° C. Δn (25° C.): 0.127 Δε: −3.0 γ.sub.1: 80 mPa .Math. s

[0072] Compared with Example 1, the refractive index of Comparative Example 1 decreased greatly and could not reach 0.140 or higher, and Tni was also slightly lost.

Comparative Example 2

[0073] The formula and corresponding properties of the liquid crystal compositions were as shown in Table 13 below.

TABLE-US-00013 TABLE 13 Formula and corresponding properties of the liquid crystal composition of Comparative Example 2 Code of liquid Class crystal monomer Content (%) I CC-3-V 20 II B-2O-O5 5 II B-2O-O6 5 III PGP-2-2V 8 IV PY-3-O2 5 V CPY-3-O2 10 V CPY-2-O2 5 V CPY-1-O2 10 V PGiY-3-O2 5 V PPY-3-O2 2 V PPY-5-O2 2 VI-C PYP-2-3 5 VIII Sc-2O-O4 5 CC-2-3 13 Properties Tni: 91.3° C. Δn (25° C.): 0.149 Δε: −4.0 γ.sub.1: 126 mPa .Math. s

[0074] Compared with Example 2, both the Tni and refractive index of Comparative Example 2 could be maintained; however, the rotational viscosity was increased by 15 mPa.Math.s than that of Comparative Example 2, and the response time became slow.

Comparative Example 3

[0075] The formula and corresponding properties of the liquid crystal compositions were as shown in Table 14 below.

TABLE-US-00014 TABLE 14 Formula and corresponding properties of the liquid crystal composition of Comparative Example 3 Code of liquid Class crystal monomer Content (%) I CC-3-V 20 CC-3-V1 10 III PGP-1-2V 5 IV PY-3-O2 5 V CPY-2-O2 6 V CPY-3-O2 10 V CPY-1-O2 10 V PGiY-3-O2 5 V PPY-3-O2 2 V PPY-5-O2 2 VI-D PYP-4-2 5 VIII Sc-2O-O5 10 VIII Sb-CpO-O5 5 VIII Sb-CpO-O4 5 Properties Tni: 93.2° C. Δn (25° C.): 0.150 Δε: −4.6 γ.sub.1: 128 mPa .Math. s

[0076] Compared with Example 3, the refractive index of Comparative Example 3 decreased slightly and the dielectric coefficient also decreased, which could lead to an increase in the required driving voltage, causing increased power consumption.

Comparative Example 4

[0077] The formula and corresponding properties of the liquid crystal compositions were as shown in Table 15 below.

TABLE-US-00015 TABLE 15 Formula and corresponding properties of the liquid crystal composition of Comparative Example 4 Code of liquid Class crystal monomer Content (%) I CC-3-V 30 II B-3O-O2 8 II B-3O-O3 4 IV CY-5-O2 4 V CPY-3-O2 10 V CPY-2-O2 10 VI PYP-2-3 12 VI PYP-2-4 12 VII CCP-V-1 10 Properties Tni: 90° C. Δn (25° C.): 0.140 Δn (60° C.): 0.122 Δε: −3.2 γ.sub.1: 94 mPa .Math. s

[0078] Compared with Example 6, although the refractive index at 25° C. and Tni of Comparative Example 4 reached consistent levels, the refractive index at high temperature was lower than that of Example 6, and the rotational viscosity was also higher, which could lead to a slow response.

[0079] In summary, by comparing the above experimental data, the liquid crystal composition of the present invention has a higher clearing point, which can achieve a higher working temperature, a refractive index of 0.140 or higher, which can meet the requirements of low cell thickness and high delay, and a better refractive index at high temperature; in addition, the present invention realizes adjustment in a wider range of dielectric constant while maintaining the above two characteristics, and can adapt to various Vop applications, and the characteristic of a lower rotational viscosity can realize a faster response.

[0080] Obviously, the above examples of the present invention are only to clearly illustrate the instances of the present invention, rather than defining the embodiments of the present invention. For those of ordinary skill in the art, other different forms of changes or variations can also be made on the basis of the above description. It is impossible to exhaustively list all the embodiments here, and all obvious changes or variations that are derived from the technical solution of the present invention are still within the scope of protection of the present invention.