LIQUID CRYSTAL COMPOSITION CONTAINING DIBENZO DERIVATIVE AND LIQUID CRYSTAL DISPLAY DEVICE

Abstract

Provided are a liquid crystal composition containing a dibenzo derivative and a liquid crystal display device. The liquid crystal composition includes at least one compound of general formula I and at least one compound of general formula II. The liquid crystal compositions have the characteristics of high clearing point, large optical anisotropy, large dielectric anisotropy, large ε.sub.⊥, large ε.sub.⊥/|Δε|, and large K.sub.ave. The liquid crystal display devices containing these liquid crystal compositions have the effects of good transmittance and high contrast. The liquid crystal composition can meet the requirements of the liquid crystal display device on low power consumption and good display effect and has high application value in liquid crystal displays of in-plane switching (IPS) mode, fringe field switching (FFS) mode, and vertical alignment (VA) mode.

##STR00001##

Claims

1. A liquid crystal composition containing a dibenzo derivative, comprising at least one compound of general formula I and at least one compound of general formula II: ##STR00091## wherein R represents —H, halogen, —CN, straight or branched alkyl containing 1 to 12 carbon atoms, ##STR00092##  wherein one or at least two non-adjacent —CH.sub.2— in the straight or branched alkyl containing 1 to 12 carbon atoms, ##STR00093##  may be respectively and independently substituted by —CH═CH—, —C≡C—, —O—, —S—, —CO—, —CO—O— or —O—CO—, and one or at least two —H in the straight or branched alkyl containing 1 to 12 carbon atoms, ##STR00094##  may be respectively and independently substituted by —F or —Cl; R.sub.x represents —H or straight or branched alkyl containing 1 to 12 carbon atoms, wherein one or at least two non-adjacent —CH.sub.2— in the straight or branched alkyl containing 1 to 12 carbon atoms may be respectively and independently substituted by —CH═CH—, —C≡C—, —O—, —S—, —CO—, —CO—O— or —O—CO—, one or at least two —H in the straight or branched alkyl containing 1 to 12 carbon atoms may be respectively and independently substituted by —F or —Cl, and R.sub.x is attached to an arbitrary carbon atom in the ring ##STR00095## R.sub.1 and R.sub.2 each independently represents straight or branched alkyl containing 1 to 12 carbon atoms, ##STR00096##  wherein one or at least two non-adjacent —CH.sub.2— in the straight or branched alkyl containing 1 to 12 carbon atoms may be respectively and independently substituted by —CH═CH—, —C≡C—, —O—, —S—, —CO—, —CO—O— or —O—CO—, one or at least two —H in the straight or branched alkyl containing 1 to 12 carbon atoms may be respectively and independently substituted by —F or —Cl, and R.sub.1 and R.sub.2 are each attached to an oxygen atom in general formula II via a carbon atom; the ring ##STR00097##  represents ##STR00098##  wherein one or at least two intra-ring single bonds in the preceding group may be substituted by a double bond(s); the ring ##STR00099##  represents ##STR00100##  wherein in ##STR00101##  one or at least two —CH.sub.2— may be substituted by —O—, and one or at most two intra-ring single bonds may be substituted by a double bond(s); and in ##STR00102##  one or at least two —H may be substituted by —F or —Cl, and one or at least two intra-ring —CH═ may be substituted by —N═; the ring ##STR00103##  represents ##STR00104##  wherein in ##STR00105##  one or at least two —H may be substituted by —F or —Cl, and one or at least two intra-ring —CH═ may be substituted by —N═; Z.sub.1 represents —(CH.sub.2).sub.aO— or —(CH.sub.2).sub.aS—, wherein a represents an integer from 0 to 7; Z.sub.2 represents —O—, —S—, —CO—O—, —O—CO—, —CF.sub.2O—, —OCF.sub.2—, —CH.sub.2O—, —CH.sub.2S—, —OCH.sub.2—, —SCH.sub.2—, —CH.sub.2—, —CH.sub.2CH.sub.2—, —(CH.sub.2).sub.4—, —CH═CH—CH.sub.2O—, —C.sub.2F.sub.4—, —CH.sub.2CF.sub.2—, —CF.sub.2CH.sub.2—, —CF═CF—, —CH═CF—, —CF═CH—, —CH═CH—, —C≡C— or a single bond; L.sub.1 and L.sub.2 each independently represents —F, —CF.sub.3 or —CHF.sub.2; X represents —CO—, —S— or —O—; n represents 0, 1 or 2, wherein when n represents 2, the ring ##STR00106##  is the same or different, and Z.sub.2 is the same or different; and m represents 0, 1 or 2, wherein when m represents 2, the ring ##STR00107##  is the same or different.

2. The liquid crystal composition according to claim 1, wherein n represents 0 or 1.

3. The liquid crystal composition according to claim 1, wherein L.sub.1 and L.sub.2 each represents —F.

4. The liquid crystal composition according to claim 1, wherein the liquid crystal composition comprises at least one compound of general formula I in which X represents —O—.

5. The liquid crystal composition according to claim 1, wherein the compound of general formula I accounts for 0.1% to 40% of the total weight of the liquid crystal composition.

6. The liquid crystal composition according to claim 1, wherein the ring ##STR00108## represents ##STR00109##

7. The liquid crystal composition according to claim 1, wherein the compound of general formula II accounts for 0.1% to 30% 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 one or at least two compounds of general formula M: ##STR00110## wherein R.sub.M1 and R.sub.M2 each independently represents straight or branched alkyl containing 1 to 12 carbon atoms, ##STR00111##  wherein one or at least two non-adjacent —CH.sub.2— in the straight or branched alkyl containing 1 to 12 carbon atoms may be respectively and independently substituted by —CH═CH—, —C≡C—, —O—, —CO—, —CO—O— or —O—CO—; the ring ##STR00112##  the ring ##STR00113##  and the ring ##STR00114##  each independently represents ##STR00115##  wherein one or at least two —CH.sub.2— in ##STR00116##  may be substituted by —O—, and at most one —H in ##STR00117##  may be substituted by halogen; Z.sub.M1 and Z.sub.M2 each independently represents a single bond, —CO—O—, —O—CO—, —CH.sub.2O—, —OCH.sub.2—, —CH═CH—, —C≡C—, —CH.sub.2CH.sub.2—, —(CH.sub.2).sub.4—, —CF.sub.2O—, —OCF.sub.2— or —CF.sub.2CF.sub.2—; n.sub.M1 represents 0, 1, 2 or 3, wherein when n.sub.M1=2 or 3, the ring ##STR00118##  is the same or different, and Z.sub.M2 is the same or different.

9. The liquid crystal composition according to claim 1, wherein the liquid crystal composition further comprises one or at least two compounds of general formula N: ##STR00119## wherein R.sub.N1 and R.sub.N2 each independently represent straight or branched alkyl containing 1 to 12 carbon atoms, ##STR00120##  wherein one or at least two non-adjacent —CH.sub.2— in the straight or branched alkyl containing 1 to 12 carbon atoms may be respectively and independently substituted by —O—, —CO—, —CO—O— or —O—CO—; one or at least two —H in the straight or branched alkyl containing 1 to 12 carbon atoms, ##STR00121##  may be respectively and independently substituted by —F or —Cl; and at least one of R.sub.N1 and R.sub.N2 is attached to the ring structure in general formula N via a carbon atom; the ring ##STR00122##  and the ring ##STR00123##  each independently represents ##STR00124##  wherein in ##STR00125##  one or at least two —CH.sub.2— may be substituted by —O—; and in ##STR00126##  one or at least two —H may be substituted by —F or —Cl, and one or at least two intra-ring —CH═ may be substituted by —N═; Z.sub.N1 and Z.sub.N2 each independently represents a single bond, —CO—O—, —O—CO—, —CH.sub.2O—, —OCH.sub.2—, —CH.sub.2CH.sub.2—, —(CH.sub.2).sub.4—, —CF.sub.2O—, —OCF.sub.2— or —CF.sub.2CF.sub.2—; L.sub.N1 and L.sub.N2 each independently represents —H or methyl; 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, the ring ##STR00127##  is the same or different, and Z.sub.N1 is the same or different.

10. The liquid crystal composition according to claim 4, wherein the liquid crystal composition comprises at least one compound of general formula I in which X represents —O— and at least one compound of general formula I in which X represents —S—.

11. The liquid crystal composition according to claim 1, wherein m represents 0 or 1.

12. The liquid crystal composition according to claim 11, wherein the liquid crystal composition comprises at least one compound of general formula II in which m=0.

13. The liquid crystal composition according to claim 11, wherein the liquid crystal composition comprises at least one compound of general formula II in which m=1.

14. The liquid crystal composition according to claim 11, wherein the liquid crystal composition comprises at least one compound of general formula II in which m=0 and at least one compound of general formula II in which m=1.

15. The liquid crystal composition according to claim 8, wherein the compound of general formula M is selected from the group consisting of the following compounds: ##STR00128## ##STR00129## ##STR00130##

16. The liquid crystal composition according to claim 15, wherein the liquid crystal composition comprises one or at least two compounds of general formula M1 in which R.sub.M1 and/or R.sub.M2 are n-propyl.

17. The liquid crystal composition according to claim 15, wherein the compound of general formula M accounts for 10% to 70% of the total weight of the liquid crystal composition.

18. The liquid crystal composition according to claim 9, wherein the compound of general formula N is selected from the group consisting of the following compounds: ##STR00131## ##STR00132## ##STR00133##

19. The liquid crystal composition according to claim 18, wherein the compound of general formula N accounts for 1% to 75% of the total weight of the liquid crystal composition.

20. A liquid crystal display device containing the liquid crystal composition according to claim 1.

Description

DETAILED DESCRIPTION

[0109] The technical solutions of the present disclosure are described below in conjunction with specific embodiments. Those skilled in the art should understand that the following embodiments are examples of the present disclosure, are used for a better understanding of the present disclosure and should not be construed as limitations to the present disclosure. Various combinations and improvements may be made within the concept of the present disclosure without departing from the spirit and scope of the present disclosure.

[0110] In the present disclosure, unless otherwise specified, the proportions mentioned in the present disclosure are weight ratios, and temperatures are Celsius temperatures.

[0111] For ease of expression, in the following examples, the group structures of the liquid crystal composition are represented by the codes listed in Table 1.

TABLE-US-00001 TABLE 1 Codes of group structures in the liquid crystal composition Group unit structure Code Group name [00076] C 1,4-cyclohexylene [00077] P 1,4-phenylene [00078] G 2-fluoro-1,4-phenylene [00079] W 2,3-difluoro-1,4-phenylene [00080] B(O) 4,6-difluoro-dibenzo[b,d]furan- 3,7-diyl [00081] B(S) 4,6-difluoro-dibenzo[b,d]thio- phene-3,7-diyl [00082] THF(2,5) tetrahydrofuran-2,5-diyl [00083] THT(2,5) tetrahydrothiophene-2,5-diyl [00084] C(5) cyclopentyl [00085] THF tetrahydrofuran-2-yl [00086] THF(3) tetrahydrofuran-3-yl [00087] DHF(1) 4,5-dihydrofuran-2-yl [00088] THT tetrahydrothiophene-2-yl [00089] THT(3) tetrahydrothiophene-3-yl —CH.sub.2CH.sub.2— 2 ethyl bridging group —CH.sub.2CH.sub.2CH.sub.2— 3 propyl bridging group —CH.sub.2O— 1O methyleneoxy —F F fluorine substituent —O— O oxygen bridging group —S— S sulphur bridging group —C.sub.nH.sub.2n+1 n (n represents a alkyl positive integer from 1 to 12) —CH═CH— or —CH═CH.sub.2 V vinyl

[0112] The following will be described with a compound of the following structure formula as an example:

##STR00090##

[0113] If represented by codes listed in Table 1, the structure formula may be expressed as: nCCGF, wherein n represents the number of C atoms of alkyl on the left terminal, for example, n is 3, which means that the alkyl is —C.sub.3H.sub.7; and, C represents 1,4-cyclohexylene, G represents 2-fluoro-1,4-phenylene, and F represents a fluorine substituent.

[0114] The abbreviated code names of the test items in the following embodiments are as follows:

[0115] Cp clearing point (nematic-isotropic phase transition temperature, ° C.)

[0116] Δε dielectric anisotropy (1 KHz, 25° C.)

[0117] ε.sub.⊥ dielectric constant perpendicular to the molecular axis (1 KHz, 25° C.)

[0118] ε.sub.⊥/|Δε| ratio of perpendicular dielectric constant to the absolute value of dielectric constant

[0119] Δn optical anisotropy (light wavelength 589 nm, 25° C.)

[0120] γ1 rotary viscosity (mPa.Math.s, 25° C.)

[0121] K.sub.ave average elastic constant

[0122] T (%) transmittance (DMS-505, cell gap 3.5 μm)

[0123] Cp: measured by using a melting point apparatus.

[0124] Δε: Δε=ε.sub.∥−ε.sub.⊥, wherein ε.sub.∥ is a dielectric constant parallel to the molecular axis, ε.sub.⊥ is a dielectric constant perpendicular to the molecular axis, and the test conditions are: 25° C., 1 KHz, and a TN90 test cell with a cell gap of 7 μm.

[0125] Δn: measured by using Abbe refractometer under the light source of sodium lamp (589 nm) and at 25° C.

[0126] γ.sub.1: measured by using LCM-2 liquid crystal physical property evaluation system with the test conditions: 25° C., 240 V, and test cell gap of 20 μm.

[0127] K.sub.ave=⅓(K.sub.11+K.sub.22+K.sub.33), and K.sub.11, K.sub.22, and K.sub.33 were calculated by testing the C-V curve of liquid crystal using the LCR instrument and anti-parallel friction cells with the test conditions: a 7 μm anti-parallel friction cell and V=0.1 V to 20 V.

[0128] Test conditions of transmittance: the V-T curve of a dimming device, whish was a negative IPS test cell with a cell gap of 3.5 μm, was tested by using DMS 505 photoelectric comprehensive tester, and the T.sub.max value in the V-T curve was the transmittance of the liquid crystal material.

[0129] Each component adopted in the following embodiments can be synthesized by using well-known methods or can be obtained commercially. These synthesis techniques are conventional, and the obtained liquid crystal compositions have been tested and proved to meet the standards of electronic compounds.

[0130] Liquid crystal compositions were prepared according to the proportions of liquid crystal compositions specified in the following examples. The preparation of the liquid crystal compositions was carried out according to the conventional methods in the art, such as heating, ultrasonic wave, suspension, and the like, and by mixing components according to specified proportions.

Comparative Example 1

[0131] A liquid crystal composition, whose components and performance parameters are shown in Table 2.

TABLE-US-00002 TABLE 2 Components and performance parameters of the liquid crystal composition Weight General Performance Component code percent formula code parameter 3CCWO2 8 N5 Cp   77 2CCWO2 8 N5 Δn 0.096 3CPWO2 8 N11 Δε  −3.6 4CPWO2 6 N11 ε⊥  6.4 5OPWO2 3 II ε⊥/|Δε|  1.78 3OPWO2 6 II γ1   95 3CWO2 6 N2 K.sub.ave  12.6 1PP2V 2 M6 T  13.1% 3CPP2 1.5 M16 3CCV 33.5 M1 3CCV1 10 M1 2OB(O)O3 2 3OB(O)O4 3 3OB(S)O5 3 Total 100

Example 1

[0132] A liquid crystal composition, whose components and performance parameters are shown in Table 3.

TABLE-US-00003 TABLE 3 Components and performance parameters of the liquid crystal composition Weight General Performance Component code percent formula code parameter 3CCWO2 8 N5 Cp   81 2CCWO2 8 N5 Δn 0.099 3CPWO2 8 N11 Δε  −3.8 4CPWO2 6 N11 ε⊥  6.9 5OPWO2 3 II ε⊥/|Δε|  1.82 3OPWO2 6 II γ1   94 3CWO2 6 N2 K.sub.ave  13.5 1PP2V 2 M6 T  14.0% 3CPP2 1.5 M16 3CCV 33.5 M1 3CCV1 10 M1 THF1OB(O)O4 2 I THF1OB(O)O5 3 I THF1OB(O)O3 3 I Total 100

Comparative Example 2

[0133] A liquid crystal composition, whose components and performance parameters are shown in Table 4.

TABLE-US-00004 TABLE 4 Components and performance parameters of the liquid crystal composition Weight General Performance Component code percent formula code parameter 3C1OWO2 6 N3 Cp   76 2CC1OWO2 10.5 N6 Δn 0.101 3CC1OWO2 10 N6 Δε  −3.6 4CC1OWO2 6 N6 ε⊥  6.1 5PWO2 7 N10 ε⊥/|Δε|  1.69 3PWO2 3 N10 γ1   103 3CPWO2 6 N11 K.sub.ave  13.5 4CPWO2 1.5 N11 T  13.5% 3CPP2 1.5 M16 3CCV 38.5 M1 3CCV1 5 M1 C(5)OB(O)O5 2 C(5)OB(S)O3 3 Total 100

Example 2

[0134] A liquid crystal composition, whose components and performance parameters are shown in Table 5.

TABLE-US-00005 TABLE 5 Components and performance parameters of the liquid crystal composition Weight General Performance Component code percent formula code parameter 3C1OWO2 6 N3 Cp   78 2CC1OWO2 10.5 N6 Δn 0.104 3CC1OWO2 10 N6 Δε  −3.7 4CC1OWO2 6 N6 ε⊥  6.9 5OPWO2 7 II ε⊥/|Δε|  1.86 3OPWO2 3 II γ1   100 3CPWO2 6 N11 K.sub.ave  13.9 4CPWO2 1.5 N11 T  14.2% 3CPP2 1.5 M16 3CCV 38.5 M1 3CCV1 5 M1 C(5)OB(O)O5 2 I C(5)OB(S)O3 3 I Total 100

Example 3

[0135] A liquid crystal composition, whose components and performance parameters are shown in Table 6.

TABLE-US-00006 TABLE 6 Components and performance parameters of the liquid crystal composition Weight General formula Performance Component code percent code parameter 3C1OWO2 11.5 N3 Cp   83 2CC1OWO2 2 N6 Δn 0.109 3CC1OWO2 12.5 N6 Δε  −3.5 2OPWO2 6.5 II ε⊥  7.5 3CCV 37 M1 ε⊥/|Δε|  2.14 3CCV1 3 M2 γ1   89 3PPWO4 2 N12 K.sub.ave  14.3 3PPWO2 2 N12 T  14.8% 5PPWO2 1 N12 4PPWO2 2 N12 3CPP2V 2 M16 3CPP2V1 3 M16 3CPWO2 9 N11 5OWO3 1.5 II THF1OB(O)O4 2.5 I THF1OB(O)O5 2.5 I Total 100

Example 4

[0136] A liquid crystal composition, whose components and performance parameters are shown in Table 7.

TABLE-US-00007 TABLE 7 Components and performance parameters of the liquid crystal composition Weight General Performance Component code percent formula code parameter 3PWO2 11.5 N10 Cp   78 2CC1OWO2 4.5 N6 Δn 0.11 3CC1OWO2 10 N6 Δε −3.8 2OPWO2 6.5 II ε⊥  7.8 3CCV 38 M1 ε⊥/|Δε| 2.05 3CCWO4 3 N5 γ1   87 3PPWO2 2 N12 K.sub.ave 14.8 4PPWO2 2 N12 T 14.5% 3CPWO2 9 N11 5OWO3O4 1.5 II C(5)OB(O)O1THF 2.5 I C(5)OB(S)O1THF 2.5 I THF1OB(S)O4 2 I THF1OB(S)O3 3 I 1PP2V 2 M6 Total 100

Example 5

[0137] A liquid crystal composition, whose components and performance parameters are shown in Table 8.

TABLE-US-00008 TABLE 8 Components and performance parameters of the liquid crystal composition General Performance Component code Weight percent formula code parameter 3PWO2 10.5 N10 Cp   80 2CC1OWO2 4.5 N6 Δn 0.11 3CC1OWO2 4 N6 Δε −4.2 2OPWO2 10.5 II ε⊥  7.9 3CCV 35 M1 ε⊥/|Δε| 1.88 3CCWO4 3 N5 γ1   82 3CPWO2 7 N11 K.sub.ave 15.1 3OWO3O4 3.5 II T 15.3% THF1OB(O)O4 2.5 I THF1OB(O)O5 2.5 I 2THF(2,5)1OB(S)O4 2 I THF1OB(S)O3 3 I C(5)1OB(S)O3 3 I C(5)1OB(O)O3 3 I C(5)1OB(O)O4 3 I C(5)1OB(S)O4 3 I Total 100

Example 6

[0138] A liquid crystal composition, whose components and performance parameters are shown in Table 9.

TABLE-US-00009 TABLE 9 Components and performance parameters of the liquid crystal composition Weight General Performance Component code percent formula code parameter 4CC1OWO2 8 N6 Cp   76 3CC1OWO2 12.5 N6 Δn 0.11 2OPWO2 7 II Δε −4.1 3PWO2 5.5 N10 ε⊥  7.5 3PPWO4 2 N12 ε⊥/|Δε| 1.83 3PPWO2 2 N12 γ1   90 3CPWO2 5 N11 K.sub.ave 14.1 4OWO3 1.5 II T 14.9% 3CCV 40.5 M1 3CPP2V 1.5 M16 3CPP2V1 1.5 M16 THF2OB(O)O4 2.5 I THF2OB(O)O5 2.5 I THF1OB(S)O4 2 I THF1OB(S)O3 3 I C(5)1OB(S)O3 3 I Total 100

Example 7

[0139] A liquid crystal composition, whose components and performance parameters are shown in Table 10.

TABLE-US-00010 TABLE 10 Components and performance parameters of the liquid crystal composition General Performance Component code Weight percent formula code parameter 3OPWO3O4 3 II Cp   91 2CC1OWO2 2.5 N6 Δn 0.107 3CC1OWO2 11 N6 Δε  −4.1 2OPWO2 6 II ε⊥  7.4 3CCV 39 M1 ε⊥/|Δε|  1.80 3CCWO4 2 N5 γ1   89 3CCWO2 2 N5 K.sub.ave   15 3CPWO2 4 N11 T  15.1% 3CPP2V 2 M16 3CPP2V1 3 M16 3CPWO2 8 N11 3OWO2 4.5 II THF1OB(O)O4 2.5 I THF1OB(O)O5 2.5 I 2THF(2,5)1OB(S)O4 4 I THF1OB(S)O4 4 I Total 100

Example 8

[0140] A liquid crystal composition, whose components and performance parameters are shown in Table 11.

TABLE-US-00011 TABLE 11 Components and performance parameters of the liquid crystal composition Weight General Performance Component code percent formula code parameter 3OPWO3O4 3 II Cp   90 2CC1OWO2 2.5 N6 Δn 0.106 3CC1OWO2 12 N6 Δε   −4 2OPWO2 6 II ε⊥  7.3 3CCV 36 M1 ε⊥/|Δε|  1.83 3CCV1 4 M1 γ1   87 3CCWO4 2 N5 K.sub.ave  15.1 3CCWO2 2 N5 T  15.3% 3CPWO2 4 N11 3CPP2V 2 M16 3CPP2V1 3 M16 3CPWO2 9 N11 2OWO3 1.5 II THF(3)1OB(O)O4 2.5 I THF(3)1OB(O)O5 2.5 I DHF(1)1OB(O)O4 4 I DHF(1)1OB(O)O5 4 I Total 100

[0141] As can be seen from the comparison between Comparative Example 1 and Example 1, the compound of general formula I of the present disclosure is more advantageous to increase ε.sub.⊥ which is the dielectric constant perpendicular to the molecular axis, ε.sub.⊥/|Δε| which is the ratio of the perpendicular dielectric to the absolute value of the dielectric, and K.sub.ave which is the average elastic constant of the liquid crystal composition, and enables the liquid crystal composition to have larger ε.sub.⊥ i.e. dielectric constant perpendicular to the molecular axis, larger ε.sub.⊥/|Δε| i.e. the ratio of perpendicular dielectric to the absolute value of the dielectric, and larger K.sub.ave i.e. average elastic constant under the premise of substantially equivalent clearing point, optical anisotropy, and dielectric anisotropy, thereby enabling the liquid crystal display device containing the liquid crystal composition to have higher transmittance and higher contrast.

[0142] As can be seen from the comparison between Comparative Example 2 and Example 2, the compound of general formula II of the present disclosure is also advantageous to increase ε.sub.⊥ which is the dielectric constant perpendicular to the molecular axis, ε.sub.⊥/|Δε| which is the ratio of the perpendicular dielectric to the absolute value of the dielectric, and K.sub.ave which is the average elastic constant of the liquid crystal composition, and can produce a more significant improvement on the transmittance and contrast of the liquid crystal composition through the synergistic effect with the compound of general formula I.

[0143] As known from Examples 1 to 8 described above, the liquid crystal compositions of the present disclosure have the characteristics of high clearing point, large optical anisotropy, large dielectric anisotropy, large ε.sub.⊥ (i.e., dielectric constant perpendicular to the molecular axis), large ε.sub.⊥/|Δε| (i.e., ratio of perpendicular dielectric to the absolute value of dielectric), and large K.sub.ave (i.e., average elastic constant); and the liquid crystal display devices containing these liquid crystal compositions have the effects of good transmittance and high contrast. The liquid crystal compositions of the present disclosure can meet the requirements of the liquid crystal display device on low power consumption and good display effect and has high application value in liquid crystal displays of IPS mode, FFS mode, and VA mode.

[0144] The applicant has stated that although the liquid crystal composition containing a dibenzo derivative and the liquid crystal display device of the present disclosure are described through the embodiments described above, the present disclosure is not limited to the processes and steps described above, which means that the implementation of the present disclosure does not necessarily depend on the processes and steps described above. It should be apparent to those skilled in the art that any improvements made to the present disclosure, equivalent replacements of raw materials selected in the present disclosure and addition of adjuvant ingredients thereof, selections of specific methods, etc., all fall within the protection scope and the disclosed scope of the present disclosure.

[0145] The above embodiments are only intended to illustrate the technical concepts and features of the present disclosure, aim to enable those familiar with the art to understand the content of the present disclosure and implement the present disclosure, and are not intended to limit the scope of the present disclosure. Equivalent changes or modifications made in accordance with the spirit of the present disclosure should be included in the scope of the present disclosure.