Background
Liquid crystal materials are mainly used in the dielectrics of liquid crystal displays, because the optical properties of such substances can be changed by an applied voltage. Electro-optical devices based on liquid crystals are well known to those skilled in the art and may contain various effects. Examples of such devices are liquid crystal cells with dynamic scattering, DAP (aligned phase deformation) liquid crystal cells, guest/host type liquid crystal cells, TN cells with twisted nematic structures, STN (super twisted nematic) liquid crystal cells, SBE (super birefringence effect) liquid crystal cells and OMI (optical film interference) liquid crystal cells. The most common displays are based on the Schadt-hellrich effect and have a twisted nematic structure. Furthermore, there are also liquid crystal cells for electric field operation parallel to the substrate and liquid crystal plane, such as IPS (in-plane switching) liquid crystal cells. In particular, TN, STN and IPS cells, in particular IPS cells, are currently commercially interesting fields of application for the liquid-crystal compositions according to the invention.
In the early 70 s of the last century, experimental studies have been conducted on the basic electro-optical characteristics of the IPS mode of uniformly aligned, twisted aligned and nematic liquid crystals, which is characterized in that a pair of electrodes are formed on the same substrate and the other substrate has no electrode, and the alignment of liquid crystal molecules is controlled by a lateral electric field applied between the electrodes, and thus this mode can also be called lateral field mode. In the IPS mode, nematic liquid crystal molecules are uniformly arranged in parallel between two substrates, and two polarizing plates are orthogonally arranged. In the IPS mode, when no electric field is applied, incident light is blocked by two orthogonal polarizing plates to be in a dark state, and when an electric field is applied, liquid crystal molecules rotate to cause retardation, so that light leaks from the two orthogonal polarizing plates.
Since the IPS modes are simple to fabricate and have a wide viewing angle, they are the most attractive method capable of improving viewing angle characteristics and realizing large-area display.
The in-plane switching mode (i.e., IPS mode) requires only a linearly polarizing plate without a compensation film, but its response speed is too slow to display a fast moving picture. Therefore, the IPS type display liquid crystal is required to have a faster response speed than the conventional TN-TFT type display mode.
The response speed of the IPS mode is related to the cell thickness in addition to the rotational viscosity.
The following is the response speed formula for IPS mode:
while the delay △ nd is fixed, a reduction in the cell thickness can be achieved by increasing Δ n, thereby greatly increasing the response speed.
In addition, for the IPS liquid crystal applied to mobile phones, flat panels and notebooks, the driving voltage can be reduced by increasing the dielectric anisotropy, and the purposes of power saving and low power consumption are achieved.
However, because of the complexity of liquid crystal mixed crystal modulation, from the viewpoint of the modulation of the liquid crystal composition material, the properties of the material (low optical anisotropy value, high dielectric anisotropy value, high resistivity, low rotational viscosity, low melting point, high clearing point, good thermal stability and ultraviolet stability, etc.) are mutually hampered, and the improvement of the properties on the one hand is accompanied by the reduction of the properties on the other hand, and it is very difficult to modulate a liquid crystal composition having suitable properties on the other hand.
Therefore, there is a need for a liquid crystal composition having a low rotational viscosity, a large optical anisotropy, and a large dielectric anisotropy, thereby reducing cell thickness and voltage, and achieving a fast response speed and low power consumption.
Disclosure of Invention
The invention aims to provide a liquid crystal composition which has the characteristics of wider nematic phase temperature range, larger optical anisotropy, larger dielectric anisotropy, higher clearing point, lower viscosity and lower threshold voltage. The display comprising the liquid crystal composition of the present invention has a fast response and excellent power saving performance.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
providing a liquid crystal composition comprising:
a first component which accounts for 5-20% of the total weight of the liquid crystal composition, wherein the first component is one or more compounds of a general formula I
(ii) 10-25% by total weight of the liquid crystal composition of a second component which is one or more compounds selected from the group consisting of compounds of formula II-1 and/or formula II-2:
a third component accounting for 10-45 percent of the total weight of the liquid crystal composition, wherein the third component is one or more compounds of a general formula III
A fourth component accounting for 1-15 percent of the total weight of the liquid crystal composition, wherein the fourth component is one or more compounds of a general formula IV
And
a fifth component accounting for 10-30% of the total weight of the liquid crystal composition, wherein the fifth component is one or more compounds of a general formula V
Wherein,
R1、R2、R3、R5and R6The same or different, each independently represents an alkyl group or an alkoxy group having 1 to 5 carbon atoms, or an alkenyl group having 2 to 5 carbon atoms;
R4represents H, an alkyl or alkoxy group having 1 to 5 carbon atoms, or an alkenyl group having 2 to 5 carbon atoms;
to represent OrWherein saidOne or more of H may be substituted by F;
andare the same or different and each independently representsOr
X1Represents an alkyl group having 1 to 5 carbon atoms or a halogen;
X2represents halogen or-OCF3;
L1And L2The same or different, each independently represents H or F;
Z1represents-CH2CH2-or a single bond;
m represents 0 or 1;
n represents 1 or 2, and when n is 2,may be the same or different.
In some embodiments, R4Represents H or an alkyl or alkoxy group having 1 to 5 carbon atoms.
In some embodiments of the present invention, the substrate is,each independently represent Or
In some embodiments of the present invention, the substrate is,to representOr
In some embodiments of the present invention, the substrate is,to representOr
In some embodiments of the present invention, the substrate is,to represent
In some embodiments of the present invention, the substrate is,to representOr
In some embodiments, preferably, X1Represents an alkyl group having 2 to 5 carbon atoms or F.
In some embodiments, the liquid crystal composition of the present invention further comprises a sixth component in an amount of 10 to 50% by weight of the total weight of the liquid crystal composition, wherein the sixth component is one or more compounds of formula VI:
wherein,
R7and R8The alkyl or alkoxy groups have 1 to 5 carbon atoms or the alkenyl groups have 2 to 5 carbon atoms;
andare the same or different and each independently represents Or
Z2represents-COO-or a single bond;
p represents 0, 1 or 2.
In some embodiments, R7Represents an alkyl group or an alkoxy group having 1 to 5 carbon atoms or an alkenyl group having 2 to 3 carbon atoms. In some embodiments, preferably, R7Represents an alkyl group or an alkoxy group having 1 to 5 carbon atoms, or a vinyl group.
In some embodiments of the present invention, the substrate is,to representOr
In some embodiments, Z2Represents a single bond.
In some embodiments of the present invention, the substrate is,to representOr
In some embodiments of the present invention, it is preferred that the first component comprises 6 to 18% by weight of the total liquid crystal composition; the second component accounts for 11-22% of the total weight of the liquid crystal composition; the third group of the liquid crystal composition accounts for 3-12% of the total weight of the liquid crystal composition; the fourth component accounts for 3-12% of the total weight of the liquid crystal composition; the fifth component accounts for 10-26% of the total weight of the liquid crystal composition; and the sixth component accounts for 10-37% of the total weight of the liquid crystal composition.
In some embodiments of the invention, the compound of formula i is selected from the group consisting of:
and
in some embodiments of the present invention, the compound of formula II-1 is selected from the group consisting of:
and
in some embodiments of the present invention, the compound of formula II-2 is selected from the group consisting of:
and
in some embodiments of the invention, the compound of formula iii is selected from the group consisting of:
and
in some embodiments, it is particularly preferred that the compound of formula III is selected from one or more compounds of the group consisting of compounds III-1, III-3, III-4, III-5, III-6, III-8, III-10 and III-11.
In some embodiments of the invention, the compound of formula iv is selected from the group consisting of:
and
in some embodiments of the invention, the compound of formula v is selected from the group consisting of:
and
in some embodiments, it is particularly preferred that the compound of formula V is selected from the group consisting of compounds of formulae V-1, V-4, V-5, V-6, V-7, V-8, V-9, V-10 and V-11.
In some embodiments of the invention, the compound of formula vi is selected from the group consisting of:
and
in some embodiments, it is particularly preferred that the compound of formula VI is selected from the group consisting of compounds of formulae VI-1, VI-2, VI-3, VI-4 and VI-6.
In some embodiments of the invention, the compound of formula III-1 is selected from the group consisting of:
and
in some embodiments of the invention, the compound of formula III-2 is selected from the group consisting of:
and
in some embodiments of the invention, the compound of formula III-3 is selected from the group consisting of:
and
in some embodiments of the invention, the compound of formula III-4 is selected from the group consisting of:
and
in some embodiments of the invention, the compound of formula III-5 is selected from the group consisting of:
and
in some embodiments of the invention, the compound of formula III-6 is selected from the group consisting of:
and
in some embodiments of the invention, the compound of formula III-7 is selected from the group consisting of:
and
in some embodiments of the invention, the compound of formula III-8 is selected from the group consisting of:
and
in some embodiments of the invention, the compound of formula III-9 is selected from the group consisting of:
and
in some embodiments of the invention, the compounds of formulas III-10 are selected from the group consisting of:
and
in some embodiments of the invention, the compounds of formula III-11 are selected from the group consisting of:
and
as a particularly preferred embodiment, the compound of formula iii is selected from the group consisting of:
and
in some embodiments of the invention, the compound of formula V-1 is selected from the group consisting of:
and
in some embodiments of the invention, the compound of formula v-2 is selected from the group consisting of:
and
in some embodiments of the invention, the compound of formula V-3 is selected from the group consisting of:
and
in some embodiments of the invention, the compound of formula v-4 is selected from the group consisting of:
and
in some embodiments of the invention, the compound of formula V-5 is selected from the group consisting of:
and
in some embodiments of the invention, the compound of formula V-6 is selected from the group consisting of:
and
in some embodiments of the invention, the compound of formula v-7 is selected from the group consisting of:
and
in some embodiments of the invention, the compound of formula V-8 is selected from the group consisting of:
and
in some embodiments of the invention, the compound of formula v-9 is selected from the group consisting of:
and
in some embodiments of the invention, the compound of formula V-10 is selected from the group consisting of:
and
in some embodiments of the invention, the compound of formula V-11 is selected from the group consisting of:
and
as a particularly preferred embodiment, the compound of formula v is selected from the group consisting of:
and
in some embodiments of the invention, the compound of formula VI-1 is selected from the group consisting of:
and
in some embodiments of the invention, the compound of formula VI-2 is selected from the group consisting of:
and
in some embodiments of the invention, the compound of formula VI-3 is selected from the group consisting of
And
in some embodiments of the invention, the compound of formula VI-4 is selected from the group consisting of:
and
in some embodiments of the invention, the compound of formula VI-5 is selected from the group consisting of:
and
in some embodiments of the invention, the compound of formula VI-6 is selected from the group consisting of:
and
in some embodiments of the invention, the compound of formula VI-7 is selected from the group consisting of:
and
as a particularly preferred embodiment, the compound of formula vi is selected from the group consisting of:
the invention also provides a liquid crystal display device which comprises the liquid crystal composition provided by the invention.
By adopting the technical scheme, compared with the prior art, the liquid crystal composition provided by the invention has the characteristics of wider nematic phase temperature range, larger optical anisotropy, higher dielectric anisotropy, higher clearing point, low threshold voltage, low viscosity and the like. The liquid crystal composition is suitable for liquid crystal display devices, so that the liquid crystal display devices have quick response and excellent electricity-saving performance.
In the present invention, unless otherwise specified, the proportions are weight ratios, all temperatures are in degrees centigrade, and the thickness of the box selected for the response time data test is 7 μm.
Detailed Description
The invention will be illustrated below with reference to specific embodiments. It should be noted that the following examples are illustrative of the present invention, and are not intended to limit the present invention. Other combinations and various modifications within the spirit or scope of the present invention may be made without departing from the spirit or scope of the present invention.
For convenience of expression, in the following examples, the group structure of the liquid crystal composition is represented by the code listed in Table 1:
TABLE 1 radical structural code of liquid crystal compounds
Compounds of the following formula are exemplified:
the structural formula is represented by the code listed in Table 2, and can be expressed as: nCPUF, where n in the code represents the number of C atoms in the left alkyl group, e.g., n is "3", i.e., the alkyl group is-C3H7(ii) a C in the code represents cyclohexane.
The abbreviated codes of the test items in the following examples are as follows:
cp (. degree. C.): clearing points (transition temperature of liquid crystal from nematic phase to isotropic phase)
Δ n: optical anisotropy (589nm, 25 ℃ C.)
Δ ε: dielectric anisotropy (1KHz, 25 ℃ C.)
Vth: threshold voltage (1KHZ, 25 ℃, TN90)
VHR (initial): voltage holding ratio (%)
γ 1: torsional viscosity (mPas at 25 ℃ C.)
Wherein, the refractive index anisotropy is measured by using an Abbe refractometer under a sodium lamp (589nm) light source at 25 ℃; the dielectric test cell was of the type TN90, the cell thickness being 7 μm.
DeltaEpsilon/(. epsilon.) -Epsilon ⊥, where ε/. is the dielectric constant parallel to the molecular axis,. epsilon. ⊥ is the dielectric constant perpendicular to the molecular axis, and the test conditions were 25 ℃ at 1KHz, the test cell was a TN90 type, and the cell thickness was 7 μm.
VHR (initial) was measured using a TOYO6254 type liquid crystal physical property evaluation system; the test temperature was 60 ℃, the test voltage was 5V, and the test time was 166.7 ms.
The components used in the following examples can be synthesized by a known method or obtained commercially. These synthesis techniques are conventional, and the resulting liquid crystal compounds were tested to meet the standards for electronic compounds.
Liquid crystal compositions were prepared according to the compounding ratios of the liquid crystal compositions specified in the following examples. The liquid crystal composition is prepared according to the conventional method in the field, such as heating, ultrasonic wave, suspension and the like, and is mixed according to the specified proportion.
Comparative example 1
The liquid crystal composition of comparative example 1, which was filled between two substrates of a liquid crystal display and subjected to a performance test, was prepared according to the compounds and weight percentages listed in table 2, and the test data are shown in the following table:
TABLE 2 liquid crystal composition formulations and their test properties
Comparative example 2
The liquid crystal composition of comparative example 2, which was filled between two substrates of a liquid crystal display and subjected to a performance test, was prepared according to the compounds and weight percentages listed in table 3, and the test data are shown in the following table:
TABLE 3 liquid crystal composition formula and its test performance
Comparative example 3
The liquid crystal composition of comparative example 3, which was filled between two substrates of a liquid crystal display and subjected to a performance test, was prepared according to the compounds and weight percentages listed in table 4, and the test data are shown in the following table:
TABLE 4 liquid crystal composition formula and its test performance