LIQUID CRYSTAL COMPOSITION, LIQUID CRYSTAL DISPLAY ELEMENT AND LIQUID CRYSTAL DISPLAY

Abstract

The present invention relates to a liquid crystal composition, a liquid crystal display element, and a liquid crystal display. Said liquid crystal composition comprises one or more compounds represented by formula I, one or more compounds represented by formula II, and one or more compounds represented by formula III: R.sub.1, R.sub.2, R.sub.3 and R.sub.4 each independently represent an alkyl group having a carbon atom number of 1-10, a fluorine-substituted alkyl group having a carbon atom number of 1-10, an alkoxy group having a carbon atom number of 1-10, a fluorine-substituted alkoxy group having a carbon atom number of 1-10, an alkenyl group having a carbon atom number of 2-10, a fluorine-substituted alkenyl group having a carbon atom number of 2-10, an alkenoxy group having a carbon atom number of 3-8 or an fluorine-substituted alkenoxy group having a carbon atom number of 3-8; R and R represent cyclopropyl, cyclopentyl or 2-tetrahydrofuranyl; and rings A and B each independently represent 1,4-phenylene or 1,4-cyclohexylene. Said liquid crystal composition is particularly suitable for use in active matrix displays, in particular for use in displays based on a VA, PSA, PA-VA, SS-VA, SA-VA, PS-VA, PALC, IPS, PS-IPS, FFS or PS-FFS effect.

##STR00001##

Claims

1. A liquid crystal composition, comprising one or more compounds represented by formula I, one or more compounds represented by formula II, and one or more compounds represented by formula III: ##STR00041## R.sub.1, R.sub.2, R.sub.3 and R.sub.4 each independently represent an alkyl group having a carbon atom number of 1-10, a fluorine-substituted alkyl group having a carbon atom number of 1-10, an alkoxy group having a carbon atom number of 1-10, a fluorine-substituted alkoxy group having a carbon atom number of 1-10, an alkenyl group having a carbon atom number of 2-10, a fluorine-substituted alkenyl group having a carbon atom number of 2-10, an alkenoxy group having a carbon atom number of 3-8 or an fluorine-substituted alkenoxy group having a carbon atom number of 3-8; R and R represent cyclopropyl, cyclopentyl or 2-tetrahydrofuranyl; and rings A and B each independently represent 1,4-phenylene or 1,4-cyclohexylene.

2. The liquid crystal composition according to claim 1, wherein said one or more compounds represented by formula I are selected from compounds represented by formulas I-1 to I-17 below, said one or more compounds represented by formula II are selected from compounds represented by formulas II-1 to II-3 below, and said one or more compounds represented by formula III are selected from compounds represented by formulas III-1 to III-3 below: ##STR00042## ##STR00043## wherein in formulas II-1 to II-3, R.sub.31 represents an alkyl group having a carbon atom number of 1-10 or an alkoxy group having a carbon atom number of 1-10; and in formulas III-1 to III-3, R.sub.41 represents an alkyl group having a carbon atom number of 1-10 or an alkoxy group having a carbon atom number of 1-10.

3. The liquid crystal composition according to claim 1, wherein in said liquid crystal composition, the total content of the compound of formula I is from 5%-70% by mass, the total content of the compound of formula II is from 1%-15% by mass, and the total content of said one or more compounds represented by formula III is 1%-15% by mass.

4. The liquid crystal composition according to claim 1, wherein said liquid crystal composition further comprises one or more compounds represented by general formula IV: ##STR00044## wherein R.sub.5 and R.sub.6 each independently represent an alkyl group having a carbon atom number of 1-10, fluorine, a fluorine-substituted alkyl group having a carbon atom number of 1-10, an alkoxy group having a carbon atom number of 1-10, a fluorine-substituted alkoxy group having a carbon atom number of 1-10, an alkenyl group having a carbon atom number of 2-10, a fluorine-substituted alkenyl group having a carbon atom number of 2-10, an alkenoxy group having a carbon atom number of 3-8 or an fluorine-substituted alkenoxy group having a carbon atom number of 3-8, wherein any one or more CH.sub.2 in the groups represented by R.sub.5 and R.sub.6 is optionally replaced by cyclopentyl, cyclobutyl or cyclopropyl; Z.sub.1 and Z.sub.2 each independently represent a single bond, CH.sub.2CH.sub.2 or CH.sub.2O; ##STR00045## each independently represent ##STR00046## m represents 1, 2 or 3; and n represents 0 or 1.

5. The liquid crystal composition according to claim 4, wherein said one or more compounds represented by formula IV are selected from the group consisting of compounds represented by formulas IV1 to IV13: ##STR00047## ##STR00048## wherein R.sub.5 and R.sub.6 each independently represent an alkyl group having a carbon atom number of 1-10, fluorine, a fluorine-substituted alkyl group having a carbon atom number of 1-10, an alkoxy group having a carbon atom number of 1-10, a fluorine-substituted alkoxy group having a carbon atom number of 1-10, an alkenyl group having a carbon atom number of 2-10, a fluorine-substituted alkenyl group having a carbon atom number of 2-10, an alkenoxy group having a carbon atom number of 3-8 or an fluorine-substituted alkenoxy group having a carbon atom number of 3-8, wherein any one or more CH.sub.2 in the groups represented by R.sub.5 and R.sub.6 is optionally replaced by cyclopentyl, cyclobutyl or cyclopropyl.

6. The liquid crystal composition according to claim 1, wherein said liquid crystal composition further comprises one or more compounds represented by general formula V: ##STR00049## R.sub.7 and R.sub.8 each independently represent an alkyl group having a carbon atom number of 1-10, a fluorine-substituted alkyl group having a carbon atom number of 1-10, an alkoxy group having a carbon atom number of 1-10, a fluorine-substituted alkoxy group having a carbon atom number of 1-10, an alkenyl group having a carbon atom number of 2-10, a fluorine-substituted alkenyl group having a carbon atom number of 2-10, an alkenoxy group having a carbon atom number of 3-8 or an fluorine-substituted alkenoxy group having a carbon atom number of 3-8, wherein any one or more non-neighboring CH.sub.2 in the groups represented by R.sub.7 and R.sub.8 are replaced by cyclopropyl; and ##STR00050## and each independently represent 1,4-phenylene, a fluorine-substituted 1,4-phenylene, 1,4-cyclohexylene or 1,4-cyclohexenylene.

7. The liquid crystal compound according to claim 6, wherein said one or more compounds represented by formula V may be selected from the group consisting of compounds represented by formulas V1 to V4: ##STR00051## R.sub.7 and R.sub.8 each independently represent an alkyl group having a carbon atom number of 1-10, a fluorine-substituted alkyl group having a carbon atom number of 1-10, an alkoxy group having a carbon atom number of 1-10, a fluorine-substituted alkoxy group having a carbon atom number of 1-10, an alkenyl group having a carbon atom number of 2-10, a fluorine-substituted alkenyl group having a carbon atom number of 2-10, an alkenoxy group having a carbon atom number of 3-8 or an fluorine-substituted alkenoxy group having a carbon atom number of 3-8, wherein any one or more non-neighboring CH.sub.2 in the groups represented by R.sub.7 and R.sub.8 are replaced by cyclopropyl.

8. The liquid crystal compound according to claim 1, wherein said liquid crystal composition further comprises one or more compounds represented by general formula VI: ##STR00052## R.sub.9 represents an alkyl group having a carbon atom number of 1-10, a fluorine-substituted alkyl group having a carbon atom number of 1-10, an alkoxy group having a carbon atom number of 1-10, a fluorine-substituted alkoxy group having a carbon atom number of 1-10, an alkenyl group having a carbon atom number of 2-10, a fluorine-substituted alkenyl group having a carbon atom number of 2-10, an alkenoxy group having a carbon atom number of 3-8 or an fluorine-substituted alkenoxy group having a carbon atom number of 3-8, wherein any one or more CH.sub.2 in R.sub.9 are optionally substituted with cyclopentyl, cyclobutyl or cyclopropyl; ##STR00053## each independently represent: ##STR00054## r represents 0, 1, 2 or 3; Z.sub.3 and Z.sub.4 each independently represent a single bond, CF.sub.2O, CH.sub.2CH.sub.2, or CH.sub.2O; and Y.sub.2 represents fluorine, a fluorine-substituted alkyl group having a carbon atom number of 1-5, a fluorine-substituted alkoxy group having a carbon atom number of 1-5, a fluorine-substituted alkenyl group having a carbon atom number of 2-5, or a fluorine-substituted alkenoxy group having a carbon atom number of 3-8.

9. The liquid crystal compound according to claim 8, wherein said one or more compounds represented by formula VI are selected from the group consisting of compounds represented by formulas VI0 to VI26: ##STR00055## ##STR00056## ##STR00057## wherein R.sub.9 represents an alkyl group having a carbon atom number of 1-10, a fluorine-substituted alkyl group having a carbon atom number of 1-10, an alkoxy group having a carbon atom number of 1-10, a fluorine-substituted alkoxy group having a carbon atom number of 1-10, an alkenyl group having a carbon atom number of 2-10, a fluorine-substituted alkenyl group having a carbon atom number of 2-10, an alkenoxy group having a carbon atom number of 3-8 or an fluorine-substituted alkenoxy group having a carbon atom number of 3-8, wherein any one or more CH.sub.2 in R.sub.9 are optionally substituted with cyclopentyl, cyclobutyl or cyclopropyl; (F) represents H or F; and in formula VI23, X.sub.1 and X.sub.2 each independently represents H or F, Y.sub.2 represents F, a fluorine-substituted alkyl group having a carbon atom number of 1-5, a fluorine-substituted alkoxy group having a carbon atom number of 1-5, a fluorine-substituted alkenyl group having a carbon atom number of 2-5, or a fluorine-substituted alkenoxy group having a carbon atom number of 3-8.

10. A liquid crystal display element or liquid crystal display comprising the liquid crystal composition of claim 1, said liquid crystal display element or liquid crystal display being an active matrix display element or display, or a passive matrix display element or display.

Description

DETAILED DESCRIPTION OF EMBODIMENTS

[0055] The present invention is further described in conjunction with particular examples below, but is not limited to the following examples. The methods described hereinafter are conventional methods unless otherwise specified. The raw materials described hereinafter can all be obtained from public commercial approaches unless otherwise specified.

[0056] The progress of a reaction is generally monitored by means of TLC during the reaction, and the post-treatment after the reaction is complete generally involves washing with water, extraction, combining and then drying organic phases, and reduced pressure distillation to remove a solvent, as well as recrystallization and column chromatography; a person skilled in the art would be able to implement the present invention according to the following description.

[0057] In the present specification, the percentages are mass percentages, the temperatures are in degree Celsius ( C.), and the specific meanings of other symbols and the test conditions are as follows:

[0058] Cp represents the clearing point ( C.) of a liquid crystal as measured by means of a DSC quantitative method;

[0059] n represents optical anisotropy, n.sub.o is the refractive index of an ordinary light, n.sub.e is the refractive index of an extraordinary light, with the test conditions being: 252 C., 589 nm and using an abbe refractometer for testing;

[0060] represents dielectric anisotropy, with =.sub.//.sub., in which .sub.// is a dielectric constant parallel to a molecular axis, and .sub. is a dielectric constant perpendicular to the molecular axis, with the test conditions being 250.5 C., a 20 micron parallel cell, and INSTEC: ALCT-IR1 for testing;

[0061] 1 represents a rotary viscosity (mPa.Math.s), with the test conditions being 250.5 C., a 20 micron parallel cell, and INSTEC: ALCT-IR1 for testing; and

[0062] T (%) represents transmittance, with T (%)=100%*bright state (Vop) luminance/light source luminance, with the test instrument being DMS501, and the test conditions being: 250.5 C., a test cell that is a 3.3 micron IPS test cell, an electrode spacing and an electrode width, both of which are 10 microns, and an included angle between the frictional direction and the electrode of 10; since .sub. has a positive correlation with T, when considering the transmittance, .sub. can be used as an indicator to testify.

[0063] In the examples of the present invention, liquid crystal monomer structures are represented by codes, and the codes for ring structures, end groups and linking groups of liquid crystals are represented in Tables (I) and (II) below.

TABLE-US-00001 TABLE (I) Codes corresponding to ring structures Ring structure Corresponding code [00024] C [00025] P [00026] G [00027] U [00028] GI [00029] P(2M) [00030] U(2M) [00031] Y [00032] A [00033] D [00034] B [00035] B(S)

TABLE-US-00002 TABLE (II) Codes corresponding to end groups and linking groups End group and linking group Corresponding code C.sub.nH.sub.2n+1 n- C.sub.nH.sub.2n+1O nO OCF.sub.3 OT CF.sub.3 -T CF.sub.2O Q F F CN N CH.sub.2CH.sub.2 E CHCH V CC T COO Z CHCHCnH2n + 1 Vn [00036] C(5) [00037] C(4) [00038] C(3)1

EXAMPLES

[0064] ##STR00039##

represents CC-3-V1,

##STR00040##

represents B(S)-1-O2

[0065] The following list involves the formulations and basic optical parameters of comparative liquid crystal compositions and 6 liquid crystal compositions:

Comparative Example 1

[0066]

TABLE-US-00003 Category Liquid crystal monomer code Content (%) V CCP-3-5 5 V CCP-3-1 2 V CPP-2-3 2 V PGP-3-2 1 IV C1OY-3-O2 10 IV CY-3-O2 10 IV CPY-3-O2 5 IV PYP-2-3 5 IV CCY-3-O2 5 IV CC1OY-3-O2 5 I CC-3-V 30 I CC-3-2 2 I CC-3-V1 2 I CC-5-V 1 I CP-3-O2 2 I PP-1-5 2 I PP-5-O2 1 II B(S)-C(5)1O-O3 5 II B(S)-C(3)1O-O4 2 II B(S)-C(5)1O-O2 3 n [589 nm, 20 C.]: 0.0981 Cp [ C.]: 85 [1 KHz, 20 C.]: 3.521 .sub.1 [mPa .Math. s, 20 C.]: 77.5449 Tr: 5.4%

TABLE-US-00004 Category Liquid crystal monomer code Content (%) V CCP-3-5 5 V CCP-3-1 2 V CPP-2-3 2 V PGP-3-2 1 IV C1OY-3-O2 10 IV CY-3-O2 10 IV CPY-3-O2 5 IV PYP-2-3 5 IV CCY-3-O2 5 IV CC1OY-3-O2 5 I CC-3-V 30 I CC-3-2 2 I CC-3-V1 2 I CC-5-V 1 I CP-3-O2 2 I PP-1-5 2 I PP-5-O2 1 III B-C(5)1O-O2 5 III B-C(5)1O-O4 2 III B-C(3)1O-O5 3 n [589 nm, 20 C.]: 0.0963 Cp [ C.]: 83 [1 KHz, 20 C.]: 3.579 .sub.1 [mPa .Math. s, 20 C.]: 73.9713 Tr: 5.3%

TABLE-US-00005 Category Liquid crystal monomer code Content (%) V CCP-3-5 5 V CCP-3-1 2 V CPP-2-3 2 V PGP-3-2 1 IV C1OY-3-O2 10 IV CY-3-O2 10 IV CPY-3-O2 5 IV PYP-2-3 5 IV CCY-3-O2 5 IV CC1OY-3-O2 5 I CC-3-V 30 I CC-3-2 2 I CC-3-V1 2 I CC-5-V 1 I CP-3-O2 2 I PP-1-5 2 I PP-5-O2 1 II B(S)-C(5)1O-O3 3 II B(S)-C(3)1O-O4 2 III B-C(5)1O-O2 3 III B-C(5)1O-O4 2 n [589 nm, 20 C.]: 0.0972 Cp [ C.]: 84 [1 KHz, 20 C.]: 3.55 .sub.1 [mPa .Math. s, 20 C.]: 70.5624 Tr: 6.0%

[0067] The liquid crystal compositions provided by Comparative Examples 1 and 2 and the liquid crystal composition provided by Example 1 are respectively poured into test cells and tested, giving the following results: the transmittance of the liquid crystal composition of Comparative Example 1 is 5.4%, the transmittance of the liquid crystal composition of Comparative Example 2 is 5.3%, and the transmittance of the liquid crystal composition of Example 1 is 6%, which is increased respectively by 11% and 13% with respect to the liquid crystal compositions of Comparative Examples 1 and 2. In addition, in the other aspects, the properties of clearing point, refractive index, dielectric, response time, etc. have no loss, so that a liquid crystal product having a fast response, a high transmittance and a good stability is obtained.

Example 2

[0068]

TABLE-US-00006 Category Liquid crystal monomer code Content (%) V CCP-3-5 2 V CCP-3-1 1 V CPP-2-3 1 V PGP-3-2 1 IV CC1OY-3-O2 5 IV CCY-3-O2 2 IV C1OY-3-O2 3 IV CY-3-O2 3 IV CPY-C(3)-O2 2 IV PYP-2-3 3 IV PY-C(5)-O2 2 IV CPY-3-O2 5 IV PPY-2-3 5 I CC-3-V 20 I CC-5-V 5 I CC-2-3 5 I CC-3-5 2 I PP-5-O2 3 I CC-V-V1 3 I CC-3-V1 2 I PP-1-5 5 III B-C(3)1O-O4 5 III B-C(5)1O-O4 2 III B-C(4)1O-O5 3 II B(S)-C(3)1O-O5 5 II B(S)-C(5)1O-O4 3 II B(S)-C(5)1O-O2 2 n [589 nm, 20 C.]: 0.1121 Cp [ C.]: 83.5 [1 KHz, 20 C.]: 3.6784 .sub.1 [mPa .Math. s, 20 C.]: 81.2455 Tr: 6.1%

[0069] The liquid crystal compositions provided by Comparative Examples 1 and 2 and the liquid crystal composition provided by Example 2 are respectively poured into test cells and tested, giving the following results: the transmittance of the liquid crystal composition of Comparative Example 1 is 5.4%, the transmittance of the liquid crystal composition of Comparative Example 2 is 5.3%, and the transmittance of the liquid crystal composition of Example 2 is 6.1%, which is increased respectively by 13% and 15% with respect to the liquid crystal compositions of Comparative Examples 1 and 2. Moreover, the liquid crystal composition of Example 2 has a larger refractive index, is suitable for display applications of low cell thickness, etc., and is advantageous for achieving a wide viewing angle, a high contrast, a high-quality dynamic picture play, etc.

Example 3

[0070]

TABLE-US-00007 Category Liquid crystal monomer code Content (%) V PGP-3-5 5 V CCP-3-1 5 V CCP-3-5 2 V CPP-2-3 3 IV CC1OY-3-O2 2 IV CCY-3-O2 2 IV C1OY-3-O2 5 IV CY-3-O2 2 IV CPY-C(3)-O2 1 IV PYP-2-3 2 IV PY-C(5)-O2 1 IV CPY-3-O2 2 IV PPY-2-3 3 I CC-2-3 18 I CP-3-O2 2 I CC-3-V 20 I CC-3-V1 10 I PP-1-5 5 I CC-3-5 5 III B-C(3)1O-O4 1 III B-C(5)1O-O4 1 II B(S)-C(3)1O-O5 1 II B(S)-C(5)1O-O4 1 II B(S)-C(5)1O-O2 1 n [589 nm, 20 C.]: 0.0931 Cp [ C.]: 85 [1 KHz, 20 C.]: 2.4 .sub.1 [mPa .Math. s, 20 C.]: 53.3256 Tr: 6.2%

[0071] The liquid crystal compositions provided by Comparative Examples 1 and 2 and the liquid crystal composition provided by Example 3 are respectively poured into test cells and tested, giving the following results: the transmittance of the liquid crystal composition of Comparative Example 1 is 5.4%, the transmittance of the liquid crystal composition of Comparative Example 2 is 5.3%, and the transmittance of the liquid crystal composition of Example 3 is 6.2%, which is increased respectively by 15% and 17% with respect to the liquid crystal compositions of Comparative Examples 1 and 2. Moreover, the liquid crystal composition of Example 3 has a lower rotary viscosity and is suitable for liquid crystal displays with a high transmittance and a fast response.

Example 4

[0072]

TABLE-US-00008 Category Liquid crystal monomer code Content (%) V CCP-3-5 5 V CCP-3-1 5 V CPP-2-3 5 V PGP-3-2 5 IV CC1OY-3-O2 5 IV CCY-3-O2 5 IV C1OY-3-O2 5 IV CY-3-O2 3 IV CPY-C(3)-O2 2 IV PYP-2-3 2 IV PY-3-O2 3 IV CPY-3-O2 2 IV PPY-2-3 3 I CC-3-V 20 I CC-3-V1 10 III B-C(3)1O-O4 7 III B-C(3)1O-O5 7 II B(S)-C(3)1O-O5 1 Other CGPC-3-3 5 n [589 nm, 20 C.]: 0.1161 Cp [ C.]: 105 [1 KHz, 20 C.]: 3.101 .sub.1 [mPa .Math. s, 20 C.]: 85 Tr: 6.1%

[0073] The liquid crystal compositions provided by Comparative Examples 1 and 2 and the liquid crystal composition provided by Example 4 are respectively poured into test cells and tested, giving the following results: the transmittance of the liquid crystal composition of Comparative Example 1 is 5.4%, the transmittance of the liquid crystal composition of Comparative Example 2 is 5.3%, and the transmittance of the liquid crystal composition of Example 4 is 6.1%, which is increased respectively by 13% and 15% with respect to the liquid crystal compositions of Comparative Examples 1 and 2. In addition, the liquid crystal composition of Example 4 has a larger refractive index, and a higher clearing point and transmittance. It is suitable for display applications of low cell thickness, etc., and has the display advantages of a high transmittance, a low power consumption and a good stability.

Example 5

[0074]

TABLE-US-00009 Category Liquid crystal monomer code Content (%) V PGP-3-5 5 V CCP-3-1 10 V CPP-2-3 5 IV PY-3-O2 10 IV CY-3-O2 10 IV C1OY-3-O2 10 I CC-3-V 20 III B-C(5)1O-O4 3 III B-C(3)1O-O5 7 II B(S)-C(3)1O-O5 5 II B(S)-C(5)1O-O4 5 Other CGPC-3-3 10 n [589 nm, 20 C.]: 0.1159 Cp [ C.]: 91 [1 KHz, 20 C.]: 3.58 .sub.1 [mPa .Math. s, 20 C.]: 83 Tr: 6.3%

[0075] The liquid crystal compositions provided by Comparative Examples 1 and 2 and the liquid crystal composition provided by Example 5 are respectively poured into test cells and tested, giving the following results: the transmittance of the liquid crystal composition of Comparative Example 1 is 5.4%, the transmittance of the liquid crystal composition of Comparative Example 2 is 5.3%, and the transmittance of the liquid crystal composition of Example 5 is 6.3%, which is increased respectively by 16.6% and 18.8% with respect to the liquid crystal compositions of Comparative Examples 1 and 2. In addition, the liquid crystal composition of Example 5 has a larger refractive index, and a higher clearing point and transmittance. It is suitable for display applications of low cell thickness, etc., and has the display advantages of a high transmittance, a low power consumption and a good stability.

Example 6

[0076]

TABLE-US-00010 Category Liquid crystal monomer code Content (%) V PGP-3-5 5 V CCP-3-1 5 V CPP-2-3 5 VI CP-3-F 5 VI CCU-3-F 5 VI CPU-3-F 5 VI CGU-3-F 1 VI PGU-3-F 2 VI PGP-3-F 2 VI CCP-3-OT 5 VI CPGU-3-F 1 VI PGUQU-3-F 2 VI PGUQU-C(3)-F 2 VI PGUQU-C(5)-F 1 VI PGUQU(2M)-3-F 2 VI PUQU-3-F 2 VI PUQU(2M)-3-F 1 VI PUQU-C(3)-F 2 VI PUQU-C(5)-F 2 IV PY-3-O2 1 IV CY-3-O2 2 IV CCY-3-O3 2 IV CC10Y-3-O2 2 IV C1OY-3-O2 2 IV CPY-3-O2 1 I CC-3-V 20 I CC-3-V1 5 I PP-1-5 4 III B-C(5)1O-O4 2 III B-C(3)1O-O5 1 II B(S)-C(3)1O-O5 2 II B(S)-C(5)1O-O4 1 n [589 nm, 20 C.]: 0.1160 Cp [ C.]: 90 [1 KHz, 20 C.]: 4.7421 .sub.1 [mPa .Math. s, 20 C.]: 71.6107 Tr: 6.0%

[0077] The liquid crystal compositions provided by Comparative Examples 1 and 2 and the liquid crystal composition provided by Example 6 are respectively poured into test cells and tested, giving the following results: the transmittance of the liquid crystal composition of Comparative Example 1 is 5.4%, the transmittance of the liquid crystal composition of Comparative Example 2 is 5.3%, and the transmittance of the liquid crystal composition of Example 6 is 6.0%, which is increased respectively by 11.1% and 13.2% with respect to the liquid crystal compositions of Comparative Examples 1 and 2. In addition, the liquid crystal composition of Example 6 has a larger refractive index, a higher clearing point, a greater dielectricity and transmittance, and a lower viscosity. It is suitable for display applications of a low cell thickness, a low power consumption, etc., and has the display advantages of a high display transmittance, a good display stability to light and heat, etc.

[0078] The liquid crystal composition of the present invention has a good stability to light and heat and a lower viscosity, can obtain a wider refractive index, a higher clearing point (a wide service temperature range), and especially has a higher light transmittance and a low threshold voltage. The liquid crystal display element or liquid crystal display using the liquid crystal composition of the present invention has a higher brightness or has an effect of saving energy and electricity.