TWI568838B - Liquid crystal composition and display device - Google Patents

Description

Liquid crystal composition and display device thereof

The present invention relates to a liquid crystal composition, and more particularly to a liquid crystal composition having suitable optical anisotropy, suitable dielectric anisotropy, higher clearing point, faster response speed, and good high temperature stability, and A liquid crystal display device of a liquid crystal composition.

The liquid crystal material is a mixture of organic rod-shaped small molecule compounds having both fluidity of liquid and anisotropy of crystal at a certain temperature. The liquid crystal display element operates by utilizing the optical anisotropy and dielectric anisotropy of the liquid crystal material itself, and has been widely used. Using different characteristics and working modes of liquid crystal materials, the device can be designed into various working modes, among which TN mode (twisted nematic mode, liquid crystal mixture has a nematic structure with a twist of about 90 degrees) is commonly used in conventional displays. , STN mode (super twisted nematic mode), SBE mode (super-twisted birefringence), ECB mode (electrically controlled birefringence), VA mode (vertical alignment), IPS (in-plane conversion), etc. The improved mode made by the model.

For liquid crystal displays, liquid crystal compounds and liquid crystal media with good chemical and thermal stability, good stability against electric field and electromagnetic radiation, proper optical anisotropy, faster response speed, and lower threshold voltage It is in line with current needs. Since liquid crystals are usually used as a mixture of various components, mutual solubility between the components is particularly important, and depending on the type of battery and the field of application, the liquid crystal must meet different requirements, such as conductivity, Dielectric anisotropy and optical anisotropy, etc., but the disadvantages that are significant in the prior art are long response times, lower resistivity and excessive operating voltages, such as EP0673986, DE19528106, DE19528107.

The response speed is an important evaluation index of the liquid crystal display. The response speed is too slow, and the display screen will have a smear phenomenon, so the liquid crystal display is required to have a fast response speed. In order to improve the response speed of the liquid crystal display, a method of reducing the thickness of the cell, improving the driving method, increasing the driving voltage, and using a liquid crystal composition that responds quickly can be selected. However, no matter which method is adopted, the other performance of the liquid crystal display will always be weakened. If the driving method is changed, the IC driving cost will increase and the circuit will be more complicated. When the driving voltage is increased, the power consumption will increase accordingly. Reducing the thickness of the box will increase the difficulty of the production process and cause defects such as uneven thickness. This leads to a decline in the yield of the liquid crystal display.

The above improvement methods are all started from the production of liquid crystal display screens. In fact, liquid crystal panel manufacturers are more inclined to choose liquid crystal materials with fast response speed to improve the response speed of liquid crystal displays. However, the performance of liquid crystal materials is mutually restricted. Accelerating the response speed often leads to a reduction in clearing points, resulting in the liquid crystal display screen not working in a high temperature environment, high and low temperature reliability can be reduced, and the liquid crystal display can be lowered at a low temperature in severe cases. Cannot display properly.

Therefore, in the field of liquid crystal materials, there is a need for a novel liquid crystal composition having improved properties. In particular, for many types of applications, the liquid crystal composition must have a suitable wide nematic phase range, a suitable refractive index, dielectric anisotropy, faster response speed, and good high temperature stability.

OBJECT OF THE INVENTION: The technical problem to be solved by the present invention is to provide a liquid crystal combination A liquid crystal composition having suitable optical anisotropy, suitable dielectric anisotropy, higher clearing point, faster response speed, and good high temperature stability. The liquid crystal composition can be applied to a liquid crystal display, and the liquid crystal display has characteristics such as short response time, high reliability, and normal operation at high temperatures.

Technical Solution: In order to solve the above technical problem, the technical solution adopted by the present invention is: a liquid crystal composition comprising: a first compound, the first compound being selected from the compound of the formula I-1, One or more compounds of the group consisting of the compounds of formula I-2 and combinations thereof a second compound, which is selected from the group consisting of a compound of the formula II-1, a compound of the formula II-2, a compound of the formula II-3, a compound of the formula II-4, and combinations thereof. One or more compounds ;as well as Wherein R ₁ and R _{2 are the} same or different and each independently represents an alkyl group having 2 to 5 carbon atoms; and R ₃ , R ₄ , R ₅ and R _{6 are the} same or different and each independently represents 1 carbon atom; -5 alkyl; L ₁ , L ₂ , L ₃ and L _{4 are the} same or different and each independently represents H or F.

In some embodiments of the invention, the first compound is one or more compounds selected from the group consisting of compounds of Formula I-1.

In some embodiments of the invention, the first compound is one or more compounds selected from the group consisting of compounds of formula 1-2.

In some embodiments of the invention, the first compound comprises from 10 to 90% by weight of the total weight of the liquid crystal composition; and the second compound comprises from 10 to 90% by weight of the total weight of the liquid crystal composition.

In some embodiments of the invention, it is preferred that the compound of formula 1-1 is selected from one or more of the group consisting of: ;as well as

In some embodiments of the invention, it is preferred that the compound of formula 1-2 is selected from one or more of the group consisting of: ;as well as

In some embodiments of the invention, it is preferred that the compound of formula II-1 is selected from one or more of the group consisting of: ;as well as As a particularly preferred embodiment, the compound of the formula II-1 is particularly preferably one or more compounds of the group consisting of: ;as well as

In an embodiment of the invention, it is preferred that the compound of the formula II-2 is selected from one or more of the group consisting of: ;as well as

In some embodiments of the invention, it is preferred that the compound of formula II-3 is selected from one or more of the group consisting of: ;as well as

As a particularly preferred embodiment, the compound of the formula II-3 is particularly preferably one or more compounds of the group consisting of: ;as well as

In some embodiments of the invention, it is preferred that the compound of formula II-4 is selected from one or more of the group consisting of: ;as well as

In some embodiments of the present invention, the liquid crystal composition further comprises: a third compound selected from the group consisting of a compound of the formula III-1, a compound of the formula III-2, and combinations thereof One or more compounds ;as well as Wherein R ₇ , R ₈ and R _{9 are the} same or different and each independently represents an alkyl group having 1 to 5 carbon atoms; and L ₅ represents H or F.

In some embodiments of the invention, the compound of Formula III-1 is selected from one or more of the group consisting of: ;as well as

In some embodiments of the invention, the compound of Formula III-2 is selected from one or more of the group consisting of: ;as well as

In some embodiments of the present invention, the liquid crystal composition of the present invention further comprises: a fourth compound selected from the group consisting of a compound of the formula IV-1, a compound of the formula IV-2, and a formula IV One or more compounds of the group consisting of -3 compounds and combinations thereof ;as well as Wherein R ₁₀ , R ₁₁ and R _{12 are the} same or different and each independently represents an alkyl group having 1 to 5 carbon atoms; and L ₆ , L ₇ and L _{8 are the} same or different and each independently represents H or F.

In some embodiments of the invention, the first compound occupies the liquid crystal group 10-45% by weight of the total compound; the second compound accounts for 15-75% by weight of the total weight of the liquid crystal composition; the third compound accounts for 15-45% of the total weight of the liquid crystal composition; The fourth compound accounts for 0-25% of the total weight of the liquid crystal composition.

In some embodiments of the present invention, the first compound accounts for 10-40% of the total weight of the liquid crystal composition; the second compound accounts for 20-65% of the total weight of the liquid crystal composition; The tri compound is 20-40% by weight based on the total weight of the liquid crystal composition; and the fourth compound is 0-15% by weight based on the total weight of the liquid crystal composition.

In some embodiments of the invention, the first compound comprises from 10% to 32% by weight of the total weight of the liquid crystal composition.

In some embodiments of the invention, the compound of Formula I-1 is from 0 to 14% by weight based on the total weight of the liquid crystal composition; the compound of Formula I-2 is based on the total weight of the liquid crystal composition 10-18%.

The present invention also provides a liquid crystal display comprising the liquid crystal composition provided by the present invention.

The present invention adopts the above technical solutions, and the technical progress obtained compared with the prior art is that the liquid crystal composition provided by the invention has suitable optical anisotropy, suitable dielectric anisotropy, high clearing point, and comparative The wide nematic phase temperature range, fast response speed, and good high temperature stability are suitable for use in liquid crystal display devices, so that the liquid crystal display device has a fast response characteristic.

In the present invention, unless otherwise specified, the ratios are all by weight, all temperatures are in degrees Celsius, and the response time data is selected to have a cell thickness of 7 μm.

The invention will now be described in connection with specific embodiments. It is to be understood that the following examples are illustrative of the invention and are not intended to limit the invention. Other combinations and various modifications within the inventive concept can be made without departing from the spirit or scope of the invention.

For ease of expression, in the following examples, the group structure of the liquid crystal composition is represented by the codes listed in Table 1:

Take a compound of the following structural formula as an example:

The structural formula is expressed by the code listed in Table 2, and can be expressed as: nCPUF, where n in the code represents the number of C atoms of the left-end alkyl group, for example, n is "3", that is, the alkyl group is -C ₃ H ₇ ; C in the code represents a cyclohexane group.

The shorthand code for the test project in the following examples is as follows:

Cp (°C): clearing point (nematic-isotropic phase transition temperature)

△n: optical anisotropy (589 nm, 20 ° C)

△ ε: dielectric anisotropy (1 kHz, 25 ° C)

Γ1: torsional viscosity (mPa*s at 20 ° C)

VHR (initial): voltage retention rate (%)

VHR (150 ° C): measured voltage retention rate after 1 h degradation at 150 ° C (%)

Among them, the refractive index anisotropy was measured by an Abbe refractometer under a sodium light (589 nm) light source at 20 ° C; the dielectric test box was a TN90 type, and the cell thickness was 7 μm.

△ ε = ε ∥ - ε ⊥, where ε ∥ is a dielectric constant parallel to the molecular axis, ε ⊥ is a dielectric constant perpendicular to the molecular axis, test conditions: 25 ° C, 1 KHz, test box is TN90 type, box 7μm thick.

VHR (initial) was tested using TOY06254 liquid crystal physical property evaluation system; test temperature was 60 ° C, test voltage was 5 V, test time was 166.7 ms; VHR (150 ° C) was to use liquid crystal at 150 ° C for 1 h after using TOY06254 liquid crystal The physical property evaluation system is tested; The test temperature was 60 ° C, the test voltage was 5 V, 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 synthetic techniques are conventional, and each of the obtained liquid crystal compounds has been tested to meet the standards of electronic compounds.

A liquid crystal composition was prepared in accordance with the ratio of each liquid crystal composition specified in the following examples. The preparation of the liquid crystal composition is carried out according to a conventional method in the art, such as heating, ultrasonic wave, suspension, etc., in a predetermined ratio.

Comparative Example 1

The liquid crystal composition of Comparative Example 1 was prepared according to each compound and weight percentage listed in Table 2, and was filled in the performance test between the two substrates of the liquid crystal display. The test data are as follows:

Example 1

The liquid crystal composition of Example 1 was prepared according to each compound and weight percentage listed in Table 3, and was filled in the performance test between the two substrates of the liquid crystal display. The test data are as follows:

Example 2

The liquid crystal composition of Example 2 was prepared according to each compound and weight percentage listed in Table 4, and was filled in the performance test between the two substrates of the liquid crystal display. The test data are as follows:

Example 3

The liquid crystal composition of Example 3 was prepared according to each compound and weight percentage listed in Table 5, and was filled in the performance test between the two substrates of the liquid crystal display. The test data are as follows:

Example 4

The liquid crystal composition of Example 4 was prepared according to each compound and weight percentage listed in Table 6, and was filled in the performance test between the two substrates of the liquid crystal display. The test data are as follows:

Example 5

The liquid crystal compositions of Example 5 were prepared according to the respective compounds and weight percentages listed in Table 7, and filled in the performance test between the two substrates of the liquid crystal display. The test data are as follows:

Example 6

The liquid crystal composition of Example 6 was prepared according to each compound and weight percentage listed in Table 8, and was filled in the performance test between the two substrates of the liquid crystal display. The test data are as follows:

Example 7

The liquid crystal composition of Example 7 was prepared according to each compound and weight percentage listed in Table 9, and was filled in the performance test between the two substrates of the liquid crystal display. The test data are as follows:

Example 8

The liquid crystal composition of Example 8 was prepared according to each compound and weight percentage listed in Table 10, and was filled in the performance test between the two substrates of the liquid crystal display. The test data are as follows:

As can be seen from the above examples, the liquid crystal composition provided by the present invention has suitable optical anisotropy, suitable dielectric anisotropy, wide nematic phase temperature range, high clearing point, and quick response. Speed and good high temperature stability are suitable for use in liquid crystal displays. And compared with Comparative Examples 1 and 2, the liquid crystal composition provided by the present invention has a shorter response time and better high temperature stability when the optical anisotropy value, the dielectric anisotropy value, and the clearing point are similar. It can meet the needs of fast response of liquid crystal display and good display under high temperature conditions, and has made obvious technological progress.

The present invention has shown through experimental results that liquid crystal compositions composed of the compounds of the formula I, II and/or III and/or IV of the present invention have experimentally obtained results showing good optical anisotropy values and dielectrics. Anisotropic values and clearing points, significantly faster response rates, and significantly better high temperature stability.

The above embodiments are merely illustrative of the technical concept and the features of the present invention, which are intended to be understood by those skilled in the art and are not intended to limit the scope of the present invention. Equivalent variations or modifications made are intended to be included within the scope of the invention.

Claims (13)

A liquid crystal composition comprising: a first compound which is one or more compounds selected from the group consisting of a compound of the formula I-1, a compound of the formula I-2, and a combination thereof a second compound which is one or more selected from the group consisting of a compound of the formula II-1, a compound of the formula II-2, a compound of the formula II-3, a compound of the formula II-4, and a combination thereof Compound And a third compound which is one or more compounds selected from the group consisting of a compound of the formula III-1, a compound of the formula III-2, and combinations thereof Wherein R ₁ and R _{2 are the} same or different and each independently represents an alkyl group having 2 to 5 carbon atoms; and R ₃ , R ₄ , R ₅ and R _{6 are the} same or different and each independently represents 1 carbon atom; -5 alkyl; R ₇ , R ₈ and R _{9 are the} same or different and each independently represents an alkyl group having 1 to 5 carbon atoms; L ₁ , L ₂ , L ₃ and L _{4 are the} same or different and are each independently L represents H or F, L ₅ represents H or F, L ₆ , L ₇ and L _{8 are the} same or different and each independently represents H or F; the first compound accounts for 10-45% of the total weight of the liquid crystal composition; The second compound accounts for 15-75% of the total weight of the liquid crystal composition; and the third compound accounts for 15-45% of the total weight of the liquid crystal composition. The liquid crystal composition according to claim 1, wherein the first compound is one or more compounds selected from the group consisting of compounds of the formula I-1. The liquid crystal composition according to claim 1, wherein the first compound is one or more compounds selected from the group consisting of compounds of the formula I-2. The liquid crystal composition according to claim 1, wherein the compound of the formula I-1 is selected from one or more of the following compound components: ;as well as And the compound of the formula I-2 is selected from one or more of the following compounds: ;as well as The liquid crystal composition according to claim 1, wherein the compound of the formula II-1 is selected from one or more of the following compound components: ;as well as The compound of the formula II-2 is selected from one or more of the following compounds: ;as well as The compound of formula II-3 is selected from one or more of the following compounds: ;as well as And the compound of the formula II-4 is selected from one or more of the following compounds: ;as well as The liquid crystal composition according to claim 1, wherein the compound of the formula III-1 is selected from one or more of the following compound components: ;as well as And the compound of the formula III-2 is selected from one or more of the following compounds: ;as well as The liquid crystal composition according to claim 6, wherein the liquid crystal composition further comprises: a fourth compound selected from the group consisting of a compound of the formula IV-1, a compound of the formula IV-2, and a formula One or more compounds of the compound of IV-3 and combinations thereof ;as well as Wherein R ₁₀ , R ₁₁ and R _{12 are the} same or different and each independently represents an alkyl group having 1 to 5 carbon atoms; and L ₆ , L ₇ and L _{8 are the} same or different and each independently represents H or F. The liquid crystal composition of claim 7, wherein the compound of the formula IV-1 is selected from one or more of the following compounds: ;as well as The compound of formula IV-2 is selected from one or more of the following compounds: ;as well as And the compound of the formula IV-3 is selected from one or more of the following compounds: ;as well as The liquid crystal composition of claim 7, wherein the first compound accounts for 10-40% of the total weight of the liquid crystal composition; the second compound accounts for 20-65% of the total weight of the liquid crystal composition; The third compound is 20-40% by weight based on the total weight of the liquid crystal composition; and the fourth compound is 0-15% by weight based on the total weight of the liquid crystal composition. The liquid crystal composition according to claim 1, wherein the first compound accounts for 10-32% of the total weight of the liquid crystal composition. The liquid crystal composition according to claim 10, wherein the compound of the formula I-1 accounts for 0-14% of the total weight of the liquid crystal composition; the compound of the formula I-2 occupies the liquid crystal composition 10-18% of the total weight. The liquid crystal composition according to claim 11, wherein the liquid crystal composition comprises: compound III-1-1 in an amount of 23% by weight based on the total weight of the liquid crystal composition; and 20% by weight of the total weight of the liquid crystal composition II-1-3; compound II-3-3 8% by weight based on the total weight of the liquid crystal composition; compound II-3-4 8% by weight based on the total weight of the liquid crystal composition; 4% by weight based on the total weight of the liquid crystal composition a compound II-4-1; 4% by weight of the total weight of the liquid crystal composition of the compound II-4-2; 3% of the total weight of the liquid crystal composition of the compound IV-3-1; Compound I-2-1 accounting for 4% by weight of the total weight of the liquid crystal composition; Compound I-2-2 5% by weight based on the total weight of the liquid crystal composition; Compound I-2-3 accounting for 4% by weight based on the total weight of the liquid crystal composition a compound I-1-1 which accounts for 4% by weight of the total weight of the liquid crystal composition; a compound I-1-2 which accounts for 4% by weight of the total weight of the liquid crystal composition; and a compound I-1- which accounts for 4% by weight of the total weight of the liquid crystal composition And a compound IV-1-4 which comprises 5% by weight based on the total weight of the liquid crystal composition; or the liquid crystal composition comprises: compound III-1-1 in an amount of 23% by weight based on the total weight of the liquid crystal composition; 20% of the compound II-1-3; the compound IV-1-3 which accounts for 3% of the total weight of the liquid crystal composition; the compound III-1-2 which accounts for 10% of the total weight of the liquid crystal composition; 4% by weight of the compound II-4-1; 4% by weight of the total weight of the liquid crystal composition of the compound II-4-2; 3% by weight of the total weight of the liquid crystal composition of the compound IV-3-1; 5% by weight of the compound I-2-1; 5% of the total weight of the liquid crystal composition of the compound I-2-2; 4% by weight of the total weight of the liquid crystal composition of the compound I-2-3; 5% of the total weight of the compound I-1-1; accounted for the liquid crystal a compound I-1-2 having a total weight of 5% by weight of the composition; 4% by weight of the total weight of the liquid crystal composition of the compound I-1-3; and 5% of the total weight of the liquid crystal composition of the compound IV-1-4; Or the liquid crystal composition comprises: compound III-1-1 which accounts for 32% of the total weight of the liquid crystal composition; and compound II-1-3 which accounts for 20% of the total weight of the liquid crystal composition; 3% by weight of the total weight of the liquid crystal composition Compound IV-1-3; compound III-2-3 which accounts for 4% by weight of the total weight of the liquid crystal composition; compound IV-1-5 which accounts for 4% of the total weight of the liquid crystal composition; and 3 of the total weight of the liquid crystal composition % of compound IV-3-1; compound I-2-1 accounting for 5% by weight of the total weight of the liquid crystal composition; compound I-2-2; 6% by weight based on the total weight of the liquid crystal composition; 4% of the compound I-2-3; 5% of the total weight of the liquid crystal composition of the compound I-1-1; 6% of the total weight of the liquid crystal composition of the compound I-1-2; 3% by weight of the compound I-1-3; and 5% of the total weight of the liquid crystal composition of the compound IV-1-4; or the liquid crystal composition comprising: 15% by weight of the total weight of the liquid crystal composition of the compound III-1 -1; compound III-1-2 in an amount of 5% by weight based on the total weight of the liquid crystal composition; compound II-4-1 in an amount of 5% by weight based on the total weight of the liquid crystal composition; and compound II in an amount of 5% by weight based on the total weight of the liquid crystal composition 4-2; accounting for the liquid crystal composition 7% of the weight of the compound Ⅳ-1-4; the total weight of the liquid crystal composition 1% Compound Ⅳ-3-1; 8% of the total weight of the compound of the liquid crystal composition II-3-3; a compound II-3-4 which accounts for 8% by weight of the total weight of the liquid crystal composition; a compound II-3-2 which accounts for 16% by weight of the total weight of the liquid crystal composition; and a compound I-2-1 which accounts for 4% of the total weight of the liquid crystal composition a compound I-2-2 in an amount of 3% by weight based on the total weight of the liquid crystal composition; a compound I-2-3 in an amount of 3% by weight based on the total weight of the liquid crystal composition; and a compound II-1 in an amount of 20% by weight based on the total weight of the liquid crystal composition -3; or the liquid crystal composition comprises: compound III-1-1 in an amount of 18% by weight based on the total weight of the liquid crystal composition; and compound III-1-2 in an amount of 5% by weight based on the total weight of the liquid crystal composition; 6% by weight of compound II-4-1; 6% of the total weight of the liquid crystal composition of the compound II-4-2; 6% of the total weight of the liquid crystal composition of the compound II-4-3; 5% by weight of the compound IV-3-1; 7% of the total weight of the liquid crystal composition of the compound II-3-3; 8% of the total weight of the liquid crystal composition of the compound II-3-4; a compound II-3-2 having a total weight of 9%; a compound I-2-1 accounting for 6% by weight of the total weight of the liquid crystal composition; and a compound I-2-2 accounting for 6% by weight of the total weight of the liquid crystal composition; 6% of the total weight of the compound I-2-3; 4% by weight of the total composition crystalline compound II-2-3; and the total weight of the liquid crystal composition 8% of the compound II-1-3; or a liquid crystal composition comprising: a compound III-1-1 which accounts for 18% by weight of the total weight of the liquid crystal composition; a compound III-1-2 which accounts for 3% by weight of the total weight of the liquid crystal composition; and a compound II-4-1 which accounts for 6% by weight of the total weight of the liquid crystal composition a compound II-4-2 which accounts for 7% by weight of the total weight of the liquid crystal composition; a compound II-4-3 which accounts for 7% by weight of the total weight of the liquid crystal composition; and a compound IV-3- which accounts for 5% by weight of the total weight of the liquid crystal composition 1; a compound II-3-3 which accounts for 7% by weight of the total weight of the liquid crystal composition; a compound II-3-4 which accounts for 8% by weight of the total weight of the liquid crystal composition; and a compound II-3 which accounts for 9% by weight of the total weight of the liquid crystal composition -2; Compound I-2-1, 5% by weight based on the total weight of the liquid crystal composition; Compound I-2-2, 5% by weight based on the total weight of the liquid crystal composition; Compound I-5% based on the total weight of the liquid crystal composition 2-3; and the compound II-1-3 which accounts for 15% by weight of the total weight of the liquid crystal composition; or the liquid crystal composition comprises: compound III-1-1 which accounts for 19% of the total weight of the liquid crystal composition; 2% of the total weight of the compound II-3-5; 7% of the total weight of the liquid crystal composition of the compound II-4-1; 8% of the total weight of the liquid crystal composition of the compound II-4-2; 7% of the total weight of the compound II-4-3; The liquid crystal composition is 5% by weight of the compound IV-3-1; the compound II-3-3 which is 10% by weight of the total weight of the liquid crystal composition; and the compound II-3-4 which is 10% by weight of the total weight of the liquid crystal composition; a compound II-3-2 in an amount of 6% by weight based on the total weight of the liquid crystal composition; a compound I-2-1 accounting for 5% by weight based on the total weight of the liquid crystal composition; and a compound I-2-2 in an amount of 4% by weight based on the total weight of the liquid crystal composition Compound 1-3, which is 3% by weight based on the total weight of the liquid crystal composition, and Compound II-1-3, which is 14% by weight based on the total weight of the liquid crystal composition. A liquid crystal display comprising the liquid crystal composition according to any one of claims 1 to 12.