CN105038814B - Liquid-crystal composition - Google Patents

Abstract

The invention discloses a liquid crystal composition, comprising one or more compounds represented by formula I and one or more compounds represented by formula II, and the liquid crystal composition comprises compounds represented by II‑A: Wherein each substituent is given its definition. The composition provided by the invention has low viscosity γ ₁ , moderate dielectric anisotropy Δε, and moderate optical anisotropy Δn, and can realize fast response of liquid crystal display.

Description

liquid crystal composition

technical field

The invention relates to the field of liquid crystal display, in particular to a liquid crystal composition and a liquid crystal display element or a liquid crystal display containing the liquid crystal composition.

Background technique

At present, the application range of liquid crystal compounds is expanding more and more widely, and it can be applied to various types of displays, electro-optic devices, sensors, and the like. There are various types of liquid crystal compounds used in the above-mentioned display fields, among which nematic liquid crystals are most widely used. Nematic liquid crystals have been used in passive TN, STN matrix displays and systems with TFT active matrix.

For the application field of thin film transistor technology (TFT-LCD), although the market has been huge in recent years and the technology has gradually matured, people's requirements for display technology are also constantly improving, especially in achieving fast response and reducing driving voltage to reduce power consumption etc. As one of the important optoelectronic materials of liquid crystal display, liquid crystal material plays an important role in improving the performance of liquid crystal display.

As a liquid crystal material, it is required to have good chemical and thermal stability as well as stability to electric fields and electromagnetic radiation. As a liquid crystal material for thin film transistor technology (TFT-LCD), it not only needs to have the above stability, but also has a wide temperature range of nematic phase, suitable birefringence anisotropy, very high resistivity, good Excellent UV resistance, high charge retention and low vapor pressure.

For dynamic picture display applications, liquid crystals are required to have a very fast response speed to eliminate afterimages and trailing of the display picture, so liquid crystals are required to have a low rotational viscosity γ ₁ ; in addition, for portable devices, in order to reduce equipment energy consumption, it is desirable that liquid crystals The driving voltage of the liquid crystal is as low as possible; and for displays such as TVs, the driving voltage requirements for liquid crystals are not so low.

The viscosity of the liquid crystal compound, especially the rotational viscosity γ ₁ , directly affects the response time of the liquid crystal after the power is applied. Both the rising time (t _on ) and the falling time (t _off ) are proportional to the rotational viscosity γ ₁ of the liquid crystal. The time (t _on ) is related to the liquid crystal cell and the driving voltage, which can be adjusted by increasing the driving voltage and reducing the thickness of the liquid crystal cell; while the falling time (t _off ) has nothing to do with the driving voltage, but is mainly related to the elastic constant of the liquid crystal It is related to the thickness of the liquid crystal cell, the drop of the cell thickness will reduce the fall time (t _off ), and in different display modes, the movement of liquid crystal molecules is not the same, the three modes of TN, IPS, and VA are respectively related to the average elastic constant K, twist The elastic constant and bending elastic constant are inversely proportional to each other.

According to the theory of liquid crystal continuum, after various liquid crystals are deformed under the action of external force (electric field, magnetic field), they will "rebound" back to their original shape through the interaction between molecules; The interaction forces form "viscosity". Small changes in liquid crystal molecules will cause obvious changes in the performance of conventional parameters of liquid crystals. Some of these changes have certain rules, and some seem to be difficult to find the rules. They will also have obvious effects on the interaction between liquid crystal molecules. These effects are very Subtle, so far there is no perfect theoretical explanation.

The viscosity of liquid crystals is related to the molecular structure of liquid crystals. It is one of the important tasks of liquid crystal formulation engineers to study the relationship between the viscosity of liquid crystal systems formed by different liquid crystal molecules and the molecular structure of liquid crystals.

Contents of the invention

The object of the present invention is to provide a liquid crystal composition and a liquid crystal display element or a liquid crystal display comprising the liquid crystal composition. The liquid crystal composition has a low viscosity, can realize fast response, and has moderate dielectric anisotropy Δε , Moderate optical anisotropy Δn, high stability to heat and light. A liquid crystal display element or a liquid crystal display comprising the liquid crystal composition has a wide nematic phase temperature range, suitable birefringence anisotropy, very high resistivity, good UV resistance, high charge retention and low vapor pressure performance.

In order to achieve the above beneficial technical effects, the present invention provides a liquid crystal composition. The liquid crystal composition provided by the present invention comprises one or more compounds represented by formula I and one or more compounds represented by formula II, and the liquid crystal composition comprises the compound represented by II-A:

Wherein, Y ₁ represents F, OCF ₃ , CF ₃ or OCF ₂ H;

R ₁ , R ₂ , and R ₃ each independently represent an alkyl group with 1-9 carbon atoms, an alkyl group with 1-9 carbon atoms substituted by fluorine, an alkoxy group with 1-9 carbon atoms, fluorine Substituted alkoxy group with 1-9 carbon atoms, alkenyl group with 2-9 carbon atoms, alkenyl group with 2-9 carbon atoms substituted by fluorine, chain with 3-8 carbon atoms Alkenyloxy or fluorine-substituted alkenyloxy with 3-8 carbon atoms;

Represents 1,4-phenylene, 1,4-cyclohexylene or 1,4-cyclohexenylene.

The liquid crystal composition provided by the present invention must contain at least one compound shown in formula I, and must contain the compound shown in formula II-A among the compounds shown in formula II, and can also contain one or more compounds shown in formula II except Other compounds other than formula II-A.

As a preferred solution, the liquid crystal composition provided by the present invention does not contain a liquid crystal compound containing -CN, and does not contain a liquid crystal compound containing a pyridine or pyrimidine ring.

In the present invention, liquid crystal compounds that do not contain a condensed ring structure are further preferred.

The liquid crystal composition provided by the present invention is Δn[589nm, 25°C]>0.08, Δε[1KHz, 25°C]>2, clearing point Cp>70.0°C, rotational viscosity γ ₁ [25°C] between 40-110mPa·s between.

In the liquid crystal composition provided by the present invention, the preferred mass content of the compound represented by Formula I is 1-20%; the preferred content of the compound represented by Formula II-A is 20-40%, and the preferred content of the compound represented by Formula II is 25-60% %.

-CN has a large permanent dipole moment, and the electron cloud is relatively rich, and it is easy to absorb cations, resulting in a decrease in the electrical properties of the liquid crystal, such as the charge retention rate VHR, resistivity ρ, power consumption, etc.; Electrons are easily excited and cause quality degradation.

Liquid crystal molecules with condensed ring structure often do not have good linearity and high viscosity, and the inclusion of these components is not conducive to improving the response speed of liquid crystals.

The compound shown in formula I is preferably the compound shown in formula I1-I4:

Wherein, R each independently represents an alkyl group with _1-9 carbon atoms, an alkyl group with 1-9 carbon atoms substituted by fluorine, an alkoxy group with 1-9 carbon atoms, or a carbon atom substituted with fluorine Alkoxy group with 1-9 carbon atoms, alkenyl group with 2-9 carbon atoms, alkenyl group with 2-9 carbon atoms substituted by fluorine, alkenyloxy group with 3-8 carbon atoms or Alkenyloxy groups with 3-8 carbon atoms substituted by fluorine;

The compound shown in formula II includes the compound shown in the formula II-A and preferably includes one or more compounds in the compounds shown in II1-II10:

The compound shown in formula I generally has good miscibility with other liquid crystals, and has a relatively high clearing point CP, generally above 200°C, but it varies with the length _of the alkyl chain of R1. When the alkyl chain is longer, the clearing point CP The CP of the bright spot will be higher, and the change of Y ₁ will also change the CP. At the same time, the dielectric anisotropy Δε will change. OCF ₃ will bring about an increase of CP relative to F by more than 10°C and an increase of the dielectric anisotropy Δε.

The dielectric anisotropy Δε of the compound shown in formula I is relatively large, between 4 and 13. Due to the large electronegativity of the substituents OCF ₃ and CF ₃ and the cumulative effect formed with the fluorine atom, the compounds shown in I3 and I1 have Larger permanent dipole moment, so the dielectric anisotropy Δε is relatively large, reaching 8 or more.

The compounds shown in formulas I1-I4 have terphenyl conjugated systems, and the compounds shown have larger optical anisotropy Δn, and I1 and I4 have larger Δn because oxygen atoms participate in conjugation. It is suitable for preparing liquid crystal mixtures with large Δn.

The compound represented by formula II-A has particularly low rotational viscosity γ ₁ , close to neutral dielectric anisotropy Δε, and small optical anisotropy Δn, and has advantages in improving liquid crystal viscosity and low-temperature performance.

The different alkyl substituents of the compound shown in formula II have an effect on the rotational viscosity γ ₁ and the clearing point CP of the liquid crystal. Generally, a longer alkyl chain or alkenyl chain will increase the rotational viscosity γ ₁ of the liquid crystal and improve the clearing point CP. Bright spot CP, but γ ₁ is higher than the compound shown in formula Ⅱ-A.

The liquid crystal composition provided by the present invention can also add one or more compounds represented by formula III

Wherein, R represents an alkyl group with 1-9 carbon atoms, an alkyl group with 1-9 carbon atoms substituted by fluorine, an alkoxy group with 1-9 carbon atoms, or an alkoxy group with 1-9 carbon atoms substituted by fluorine _. -9 alkoxy group, alkenyl group with 2-9 carbon atoms, alkenyl group with 2-9 carbon atoms substituted by fluorine, alkenyloxy group with 3-8 carbon atoms or fluorine substituted Alkenyloxy groups with 3-8 carbon atoms;

Represents 1,4-phenylene, 1,4-cyclohexylene or 1,4-cyclohexenylene.

In the liquid crystal composition provided by the present invention, the compound represented by formula III preferably has a mass content of 5-20%.

The compound represented by the formula III is specifically preferably:

The compound shown in formula III has moderate optical anisotropy Δn, dielectric anisotropy Δε between 5-9, low rotational viscosity γ ₁ , and clearing point CP generally above 120°C, which can be used to adjust mixed liquid crystal CP, Δn , Δε, γ ₁ and other parameters. Among the compounds represented by formula III, compounds in which R ₁ represents a C ₁ -C ₅ linear alkyl group are preferred.

In the liquid crystal composition provided by the present invention, one or more compounds represented by formula IV can also be added:

Wherein, R ₅ represents an alkyl group with 1-9 carbon atoms, an alkyl group with 1-9 carbon atoms substituted by fluorine, an alkoxy group with 1-9 carbon atoms, or an alkoxy group with 1-9 carbon atoms substituted by fluorine. -9 alkoxy group, alkenyl group with 2-9 carbon atoms, alkenyl group with 2-9 carbon atoms substituted by fluorine, alkenyloxy group with 3-8 carbon atoms or fluorine substituted Alkenyloxy groups with 3-8 carbon atoms;

n means 0 or 1;

(F) means H or F.

In the liquid crystal composition provided by the present invention, the preferred mass content of the compound represented by formula IV is 5-20%.

Among the compounds represented by formula IV, compounds in which R ₁ represents a C ₁ -C ₅ linear alkyl group are preferred. The compound shown in formula IV has moderate Δε, high CP, and low viscosity is suitable for adjusting the viscosity, CP, and Δε of liquid crystal.

The compound shown in formula IV is additionally preferably:

The liquid crystal composition provided by the present invention can also add one or more compounds represented by formula V:

Wherein, R ₆ and R ₇ each independently represent an alkyl group with 1-9 carbon atoms, an alkyl group with 1-9 carbon atoms substituted by fluorine, an alkoxy group with 1-9 carbon atoms, a fluorine-substituted Alkoxy groups with 1-9 carbon atoms, alkenyl groups with 2-9 carbon atoms, alkenyl groups with 2-9 carbon atoms substituted by fluorine, alkenyl groups with 3-8 carbon atoms Alkenyloxy group with 3-8 carbon atoms substituted by oxy group or fluorine;

Y ₃ and Y ₄ represent H or F, but not F at the same time;

Represents 1,4-phenylene, 1,4-cyclohexylene or 1,4-cyclohexenylene.

In the liquid crystal composition provided by the present invention, the preferred mass content of the compound represented by formula V is 2-15%.

The compound represented by formula V is preferably a compound in which R ₆ and R ₇ represent a C ₁ -C ₅ linear alkyl group. The compound represented by the formula V has a very high CP, which is beneficial to expand the use temperature range of the liquid crystal.

The compound shown in formula V is additionally preferably:

Compounds R ₆ and R ₇ represented by formula V are preferably C ₁ -C ₅ linear alkyl groups.

The liquid crystal composition provided by the present invention can also add one or more compounds represented by formula VI

Wherein, R ₈ represents an alkyl group with 1-9 carbon atoms, an alkyl group with 1-9 carbon atoms substituted by fluorine, an alkoxy group with 1-9 carbon atoms, or an alkoxy group with 1-9 carbon atoms substituted by fluorine. -9 alkoxy group, alkenyl group with 2-9 carbon atoms, alkenyl group with 2-9 carbon atoms substituted by fluorine, alkenyloxy group with 3-8 carbon atoms or fluorine substituted Alkenyloxy groups with 3-8 carbon atoms;

Represents 1,4-phenylene, 1,4-cyclohexylene or 1,4-cyclohexenylene;

Represents 1,4-phenylene, fluorinated 1,4-phenylene, 1,4-cyclohexylene or 1,4-cyclohexenylene;

R is selected from F, an alkyl group with _1-9 carbon atoms, an alkyl group with 1-9 carbon atoms replaced by fluorine, an alkoxyl group with 1-9 carbon atoms, and an alkyl group with 1-9 carbon atoms replaced by fluorine. Alkoxy with 1-9, alkenyl with 2-9 carbon atoms, alkenyl with 2-9 carbon atoms substituted by fluorine, alkenyloxy with 3-8 carbon atoms or fluorine substituted Alkenyloxy groups with 3-8 carbon atoms.

In the liquid crystal composition provided by the present invention, the preferred mass content of the compound represented by formula VI is 5-30%.

The compound shown in formula VI is additionally preferably:

The compounds represented by formulas VI-1 and VI-2 have dielectric anisotropy Δε close to neutral, low rotational viscosity γ ₁ , high clearing point, and large K value, and can be used to adjust the K value and γ ₁ of liquid crystals , so as to achieve a fast response. The compound shown in terphenyls VI-5 has a large optical anisotropy Δn due to its large conjugated system, and is especially suitable for preparing mixed liquid crystals with a large refractive index.

The liquid crystal composition provided by the present invention can also add one or more compounds represented by formula VII

Wherein, R ₁₀ represents an alkyl group with 1-9 carbon atoms, an alkyl group with 1-9 carbon atoms substituted by fluorine, an alkoxy group with 1-9 carbon atoms, or an alkoxy group with 1-9 carbon atoms substituted by fluorine. -9 alkoxy group, alkenyl group with 2-9 carbon atoms, alkenyl group with 2-9 carbon atoms substituted by fluorine, alkenyloxy group with 3-8 carbon atoms or fluorine substituted Alkenyloxy groups with 3-8 carbon atoms;

Represents one of 1,4-phenylene, fluorinated 1,4-phenylene, 1,4-cyclohexylene, 1,4-cyclohexenylene and/or 1,4-cyclohexylene or One or more of the groups formed by replacing two unconnected CH ₂ with oxygen;

p means 2 or 3.

In the liquid crystal composition provided by the present invention, the compound represented by formula VII preferably has a mass content of 5-55%.

The compound shown in formula VII is additionally preferably:

The compound represented by formula VII has a large dielectric anisotropy Δε and a low rotational viscosity γ ₁ , and can be used to prepare a liquid crystal mixture to reduce the driving voltage of the liquid crystal and accelerate the response speed of the display device.

The liquid crystal composition provided by the present invention, on the basis of including or not including compounds represented by formula III, formula IV, formula V, formula VI, formula VII, may also contain one or more formulas VIII-1, VIII- 2 and/or compounds containing cycloalkyl groups shown in VIII-3

in, Each independently represents 1,4-cyclohexylene, a group formed by replacing one or two unconnected CH ₂ in 1,4-cyclohexylene with O, 1,4-phenylene and/or fluoro One or more of 1,4-phenylene;

Z ₁ , Z ₂ , and Z ₃ each independently represent a single bond, -CF ₂ O- or -CH ₂ O-;

m, k, g each independently represent 1, 2 or 3;

i represents 0, 1 or 2;

R ₁₁ represents F, an alkyl group with 1-9 carbon atoms, an alkyl group with 1-9 carbon atoms substituted by fluorine, an alkoxy group with 1-9 carbon atoms, or 1 carbon atom substituted with fluorine -9 alkoxy group, alkenyl group with 2-9 carbon atoms, alkenyl group with 2-9 carbon atoms substituted by fluorine, alkenyloxy group with 3-8 carbon atoms or fluorine substituted Alkenyloxy groups with 3-8 carbon atoms;

R ₁₂ represents an alkyl group with 1-5 carbon atoms, an alkyl group with 1-5 carbon atoms substituted by fluorine, an alkoxy group with 1-5 carbon atoms, or an alkyl group with 1-5 carbon atoms substituted by fluorine Alkoxy group, alkenyl group with 2-5 carbon atoms, alkenyl group with 2-5 carbon atoms substituted by fluorine, alkenyloxy group with 3-5 carbon atoms or carbon atom substituted by fluorine The alkenyloxy group whose number is 3-5.

The compound shown in formula VIII does not contain a soft terminal alkyl chain, so it has strong rigidity, and the change of the relative interaction between liquid crystal molecules shows a larger K value and a higher CP.

The compound shown in VIII-1 is preferably:

The compound shown in Ⅷ-2 is preferably:

The compound shown in Ⅷ-3 is preferably:

The different proportions of the components of the liquid crystal composition will show slightly different properties, such as dielectric anisotropy Δε, optical anisotropy Δn, transition temperature point CP of liquid crystal nematic phase into liquid, stability at low temperature will be different, and can be applied to different types of display devices, but the same feature is that its rotational viscosity γ ₁ is relatively low. Applied to liquid crystal display devices, fast response can be achieved.

Dopants with various functions can also be added to the liquid crystal compound provided by the present invention. The dopant content is preferably between 0.01-1%. These dopants are mainly antioxidants, ultraviolet absorbers, and chiral agents.

Antioxidant, UV absorber preferred:

S represents an integer of 1-10.

Chiral agent preferred (left-handed or right-handed):

The present invention also relates to a liquid crystal display element or a liquid crystal display comprising any one of the above-mentioned liquid crystal compositions; the display element or display is an active matrix display element or display or a passive matrix display element or display.

The liquid crystal display element or liquid crystal display is preferably an active matrix addressed liquid crystal display element or liquid crystal display.

The active matrix display element or display is specifically a TN-TFT or IPS-TFT liquid crystal display element or display.

The liquid crystal composition provided by the invention has low viscosity, can realize fast response, and has moderate dielectric anisotropy Δε, moderate optical anisotropy Δn, and high stability to heat and light.

The liquid crystal material comprising the liquid crystal composition provided by the invention not only has good chemical and thermal stability, but also stability to electric field and electromagnetic radiation. Moreover, as a liquid crystal material for thin-film transistor technology (TFT-LCD), it also has a wide nematic phase temperature range, suitable birefringence anisotropy, very high resistivity, good UV resistance, and high charge retention. efficiency and low vapor pressure.

Detailed ways

The present invention will be further described below in conjunction with specific examples, but the present invention is not limited to the following examples. The methods are conventional methods unless otherwise specified. The raw materials can be obtained from public commercial sources unless otherwise specified. Said percentages are all mass percentages unless otherwise specified.

In the following examples,

CP stands for clearing point, which is directly measured by WRX-1S thermal microanalyzer, and the heating rate is set at 3°C/min.

Δn represents optical anisotropy (589nm, 20°C),

Δε represents dielectric anisotropy (25°C, 1KHz, HP4284A, 5.2 micron TN left-handed box),

γ ₁ represents rotational viscosity (mpas) at 20°C, VHR (%) represents charge retention (5V, 60Hz, 20°C), ρ(×10 ¹³ Ω·cm) represents resistivity (20°C)

The tester for the voltage retention rate VHR (%) and the resistivity ρ (×10 ¹³ Ω·cm) are both TOYO06254 and TOYO6517 liquid crystal physical property evaluation systems (test temperature 20°C, time 16ms, test box 7.0 microns)

Example 1

Δε[1KHz,20℃]: 9.0

Δn[589nm, 20°C]: 0.125

Cp: 118°C

γ ₁ : 158mPa.s.

Example 2

Δε[1KHz,20℃]: 4.2

Δn[589nm, 20°C]: 0.104

Cp: 130°C

γ ₁ : 175mPa.s.

Example 3

Δε[1KHz,20℃]: 9.9

Δn[589nm, 20°C]: 0.116

Cp: 79°C

γ ₁ : 77mPa.s.

Example 4

Δε[1KHz,20℃]: 8.7

Δn[589nm, 20°C]: 0.106

Cp: 99°C

γ ₁ : 98mPa.s.

Example 5

Δε[1KHz,20℃]: 9.0

Δn[589nm, 20°C]: 0.155

Cp: 104°C

γ ₁ : 112mPa.s.

Example 6

Δε[1KHz,20℃]: 5.6

Δn[589nm, 20°C]: 0.109

Cp: 112°C

γ ₁ : 121 mPa.s.

Example 7

Δε[1KHz,20℃]: 4.2

Δn[589nm, 20°C]: 0.14

Cp: 143°C

γ ₁ : 280mPa.s.

It can be seen from the above examples that the liquid crystal composition of the present invention has a relatively low rotational viscosity γ ₁ and can be used for liquid crystal display to achieve fast response. It is especially suitable for liquid crystal materials used in TN and IPS modes.

Claims (9)

1. A liquid crystal composition comprising one or more compounds of formula i and one or more compounds of formula ii, and wherein said liquid crystal composition comprises a compound of formula ii-a:

wherein, Y₁Representation F, CF₃、OCF₂H；

R₁、R₂、R₃Each independently represents an alkyl group having 1 to 9 carbon atoms, a fluorine-substituted alkyl group having 1 to 9 carbon atoms, an alkoxy group having 1 to 9 carbon atoms, a fluorine-substituted alkoxy group having 1 to 9 carbon atoms, an alkenyl group having 2 to 9 carbon atoms, a fluorine-substituted alkenyl group having 2 to 9 carbon atoms, an alkenyloxy group having 3 to 8 carbon atoms or a fluorine-substituted alkenyloxy group having 3 to 8 carbon atoms;

represents 1, 4-phenylene, 1, 4-cyclohexylene or 1, 4-cyclohexenylene;

the liquid crystal composition also comprises one or more compounds shown as a formula VIII-1, one or more compounds shown as a formula VIII-2 and/or one or more compounds shown as a formula VIII-3:

wherein,each independently represents one or two unconnected CH groups in 1, 4-cyclohexylene group and 1, 4-cyclohexylene group₂One or more of a group formed by substitution with O, 1, 4-phenylene and/or fluorinated 1, 4-phenylene;

Z₁、Z₂、Z₃each independently represents a single bond, -CF₂O-or-CH₂O-；

m, k, g each independently represent 1, 2 or 3;

i represents 0, 1, 2;

R₁₁represents F, an alkyl group having 1 to 9 carbon atoms, a fluorine-substituted alkyl group having 1 to 9 carbon atoms, an alkoxy group having 1 to 9 carbon atoms, a fluorine-substituted alkoxy group having 1 to 9 carbon atoms, an alkenyl group having 2 to 9 carbon atoms, a fluorine-substituted alkenyl group having 2 to 9 carbon atoms, an alkenyloxy group having 3 to 8 carbon atoms or a fluorine-substituted alkenyloxy group having 3 to 8 carbon atoms;

R₁₂represents an alkyl group having 1 to 5 carbon atoms, a fluorine-substituted alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a fluorine-substituted alkoxy group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, a fluorine-substituted alkenyl group having 2 to 5 carbon atoms, an alkenyloxy group having 3 to 5 carbon atoms or a fluorine-substituted alkenyloxy group having 3 to 5 carbon atoms.

2. The liquid crystal composition of claim 1, wherein the one or more compounds of formula i are one or more of the following compounds:

wherein R is₁Each independently represents an alkyl group having 1 to 9 carbon atoms, a fluorine-substituted alkyl group having 1 to 9 carbon atoms, an alkoxy group having 1 to 9 carbon atoms, a fluorine-substituted alkoxy group having 1 to 9 carbon atoms, an alkenyl group having 2 to 9 carbon atoms, a fluorine-substituted alkenyl group having 2 to 9 carbon atoms, an alkenyloxy group having 3 to 8 carbon atoms or a fluorine-substituted alkenyloxy group having 3 to 8 carbon atoms;

the one or more compounds of formula II comprise one or more compounds of formulae II 1-II 10:

3. the liquid crystal composition of claim 1 or 2, further comprising one or more compounds of formula iii:

wherein R is₄Represents an alkyl group having 1 to 9 carbon atoms, a fluorine-substituted alkyl group having 1 to 9 carbon atoms, or an alkoxy group having 1 to 9 carbon atomsA fluoro-substituted alkoxy group having 1 to 9 carbon atoms, a C2-9 alkenyl group, a fluoro-substituted alkenyl group having 2 to 9 carbon atoms, a C3-8 alkenyloxy group or a fluoro-substituted alkenyloxy group having 3 to 8 carbon atoms;

represents a 1, 4-phenylene group, a 1, 4-cyclohexylene group or a 1, 4-cyclohexenylene group.

4. The liquid crystal composition of claim 1 or 2, further comprising one or more compounds of formula iv:

wherein R is₅Represents an alkyl group having 1 to 9 carbon atoms, a fluorine-substituted alkyl group having 1 to 9 carbon atoms, an alkoxy group having 1 to 9 carbon atoms, a fluorine-substituted alkoxy group having 1 to 9 carbon atoms, an alkenyl group having 2 to 9 carbon atoms, a fluorine-substituted alkenyl group having 2 to 9 carbon atoms, an alkenyloxy group having 3 to 8 carbon atoms or a fluorine-substituted alkenyloxy group having 3 to 8 carbon atoms;

n represents 0 or 1;

(F) represents H or F.

5. The liquid crystal composition of claim 1 or 2, further comprising one or more compounds of formula v:

wherein R is₆、R₇Each independently represents an alkyl group having 1 to 9 carbon atoms, a fluorine-substituted alkyl group having 1 to 9 carbon atoms, an alkoxy group having 1 to 9 carbon atoms, a fluorine-substituted alkoxy group having 1 to 9 carbon atoms, or an alkenyl group having 2 to 9 carbon atomsA fluorine-substituted alkenyl group having 2 to 9 carbon atoms, a carbon-3 to 8 alkenyloxy group or a fluorine-substituted alkenyloxy group having 3 to 8 carbon atoms;

Y₃、Y₄h or F, but not both;

represents a 1, 4-phenylene group, a 1, 4-cyclohexylene group or a 1, 4-cyclohexenylene group.

6. The liquid crystal composition of claim 1 or 2, further comprising one or more compounds of formula vi:

wherein R is₈Represents an alkyl group having 1 to 9 carbon atoms, a fluorine-substituted alkyl group having 1 to 9 carbon atoms, an alkoxy group having 1 to 9 carbon atoms, a fluorine-substituted alkoxy group having 1 to 9 carbon atoms, an alkenyl group having 2 to 9 carbon atoms, a fluorine-substituted alkenyl group having 2 to 9 carbon atoms, an alkenyloxy group having 3 to 8 carbon atoms or a fluorine-substituted alkenyloxy group having 3 to 8 carbon atoms;

represents 1, 4-phenylene, 1, 4-cyclohexylene or 1, 4-cyclohexenylene;

represents 1, 4-phenylene, fluoro-1, 4-phenylene, 1, 4-cyclohexylene or 1, 4-cyclohexenylene;

R₉f, an alkyl group having 1 to 9 carbon atoms, a fluorine-substituted alkyl group having 1 to 9 carbon atoms, a carbon 1 to 9 alkoxy group, a fluorine-substituted alkoxy group having 1 to 9 carbon atoms, a carbon 2 to 9 alkenyl group, a fluorine-substituted alkyl group having 1 to 9 carbon atomsAn alkenyl group having 2 to 9 carbon atoms, an alkenyloxy group having 3 to 8 carbon atoms or a fluorine-substituted alkenyloxy group having 3 to 8 carbon atoms.

7. The liquid crystal composition of claim 1 or 2, further comprising one or more compounds of formula vii:

wherein R is₁₀Represents an alkyl group having 1 to 9 carbon atoms, a fluorine-substituted alkyl group having 1 to 9 carbon atoms, an alkoxy group having 1 to 9 carbon atoms, a fluorine-substituted alkoxy group having 1 to 9 carbon atoms, an alkenyl group having 2 to 9 carbon atoms, a fluorine-substituted alkenyl group having 2 to 9 carbon atoms, an alkenyloxy group having 3 to 8 carbon atoms or a fluorine-substituted alkenyloxy group having 3 to 8 carbon atoms;

represents one or two CH groups which are not linked in 1, 4-phenylene, fluorinated 1, 4-phenylene, 1, 4-cyclohexylene, 1, 4-cyclohexenylene and/or 1, 4-cyclohexylene₂Substitution of one or more of the groups formed by oxygen;

p represents 2 or 3.

8. A liquid crystal display element or a liquid crystal display, characterized in that the liquid crystal display element or the liquid crystal display comprises the liquid crystal composition according to any one of claims 1 to 7; the display element or display is an active matrix display element or display or a passive matrix display element or display.

9. The liquid crystal display element or the liquid crystal display according to claim 8, wherein the active matrix display element or the display is a TN-TFT or IPS-TFT liquid crystal display element or display.