TWI813031B - Liquid crystal composition, liquid crystal display element and liquid crystal display - Google Patents

Abstract

The invention belongs to the technical field of liquid crystal materials, and specifically relates to a liquid crystal composition and a liquid crystal display element or liquid crystal display containing the liquid crystal composition. The invention discloses a liquid crystal composition, which contains one or more compounds represented by formula I and one or more compounds represented by formula II. The liquid crystal composition of the present invention has strong alignment force, can effectively improve stains on liquid crystal display panels, and is mainly used in the field of large-size 8K liquid crystal displays.

Description

Liquid crystal composition, liquid crystal display element and liquid crystal display

The present invention relates to the technical field of liquid crystal display. More specifically, it relates to a liquid crystal composition and a liquid crystal display element containing the liquid crystal composition.

With the advancement of technology and increasing demand, people are paying more and more attention to the display effects of display terminal products, such as wider color gamut, high contrast, fast response speed, and better and clearer display images. The mainstream display terminal products in the market all use TFT-LCD as the display panel, and abnormal local image quality of display terminal products is one of the common quality problems. Common image quality display abnormalities usually manifest themselves in the following forms: Image Stacking: When the TFT-LCD display is powered on and displays the same picture for a long time, and then switches to the next picture, the previous picture will appear. It will remain in the next picture. This phenomenon is called afterimage. This phenomenon will become weaker and weaker and even disappear as time goes by and the picture is switched. Different levels of afterimages will affect the quality of the monitor's display to varying degrees, resulting in less than optimal visual effects.

Flicker: It is the flicker of the liquid crystal when it is powered on and driven in the display panel, that is, the brightness changes with the refresh frequency or drive frequency. It can also be considered as the periodic change of the liquid crystal transmittance. The accurate definition is positive frame and negative frame. The difference in transmittance between frames divided by the average transmittance. When the flicker is severe, it will also cause visual fatigue to the human eye.

Zara defect: Zara originates from Japanese and generally refers to the tiny light leakage that occurs in the display area of the LCD panel under dark conditions. Zara defectiveness is an important indicator affecting panel yield.

Stains: When the LCD monitor is lit for a long time and displays the same picture, local black stains on the surface and edges will gradually appear. In fact, serious light leakage occurs locally. The main causes of in-plane and edge stains include, for example, the alignment force difference between PI materials and liquid crystal materials caused by impurities, ions and other factors.

As the size of display products becomes larger and the resolution becomes higher, the display quality of display terminals is also facing huge challenges. Currently commonly used liquid crystal compositions with negative dielectric anisotropy can be successfully used in medium and large-sized FHD, 4K and other panel specifications. However, large-sized 8K products with relatively high specifications will face the problem of long-term lighting of the display. Quality problems such as stains. Therefore, developing a high-quality liquid crystal material is the key to solving the current image quality problems of display terminals.

The technical solution provided by the present invention has the conventional performance of liquid crystal, with high clearing point, large refractive index, good mutual solubility, good reliability, especially strong alignment force, and can effectively improve the in-plane and edge stains of the display. .

In order to achieve the above beneficial technical effects, the present invention provides a liquid crystal composition, which contains one or more compounds represented by formula I and one or more compounds represented by formula II,

表示

、

或

；

、

各自獨立地表示

、

、

或

；m表示1或2；當m表示2時

可相同或不同；n表示0或1。 Among them, R ₁ represents an alkenyl group with a carbon number of 2-10; R ₂ represents an alkoxy group with a carbon number of 1-10; R ₃ represents an alkyl group with a carbon number of 1-10; Z ₁ represents a single bond or -CH ₂ O-;

express

,

or

;

,

represent each independently

,

,

or

;m represents 1 or 2; when m represents 2

Can be the same or different; n represents 0 or 1.

The second object of the present invention is to provide a liquid crystal display element, which is mainly used in the field of large-size 8K liquid crystal display.

The third object of the present invention is to provide a liquid crystal display, which is mainly used in the field of large-size 8K liquid crystal display.

The liquid crystal composition provided by the technical solution of the present invention has high clearing point, large refractive index, good mutual solubility, good reliability, especially strong alignment force, and can effectively improve the in-plane and edge stains of the display. Mainly Applied to large-size 8K LCD display field.

The present invention provides a liquid crystal composition, which contains one or more compounds represented by formula I and one or more compounds represented by formula II,

表示

、

或

；

、

各自獨立地表示

、

、

或

； m表示1或2；當m表示2時

可相同或不同；n表示0或1。 Among them, R ₁ represents an alkenyl group with a carbon number of 2-10; R ₂ represents an alkoxy group with a carbon number of 1-10; R ₃ represents an alkyl group with a carbon number of 1-10; Z ₁ represents a single bond or -CH ₂ O-;

express

,

or

;

,

represent each independently

,

,

or

; m represents 1 or 2; when m represents 2

Can be the same or different; n represents 0 or 1.

The terminal alkenyl group of the compound represented by formula I of the liquid crystal composition provided by the present invention is combined with the compound represented by formula II. It has a high refractive index and a strong alignment force, which can effectively improve the in-plane and edge of the liquid crystal display. stain problems while having a faster response time.

In the liquid crystal composition of the present invention, preferably, the compound represented by formula I in the aforementioned liquid crystal composition is selected from the group consisting of the compounds represented by the following formulas I-1 to I-3,

Wherein, R ₁ represents an alkenyl group having 2 to 10 carbon atoms; R ₂ represents an alkoxy group having 1 to 10 carbon atoms.

In the liquid crystal composition of the present invention, preferably, the compounds represented by the aforementioned formulas I-1 to I-3 are selected from the group consisting of the compounds represented by the following formulas I-1-1 to I-3-2,

The compound represented by formula II in the aforementioned liquid crystal composition is selected from the group consisting of the compounds represented by the following formulas II-1 to II-4,

The liquid crystal composition of the present invention, preferably, the liquid crystal composition further contains one or more compounds represented by formula III,

Wherein, R ₄ and R ₅ each independently represent an alkyl group having 1 to 10 carbon atoms.

In the liquid crystal composition of the present invention, preferably, the compound represented by formula III contains at least one terminal methyl compound.

In the liquid crystal composition of the present invention, preferably, the compound represented by formula III contains at least the compound represented by formula III-1,

The liquid crystal composition of the present invention, preferably, the aforementioned liquid crystal composition also contains one or more compounds represented by formula IV,

Wherein, R ₆ represents an alkyl group having 1 to 10 carbon atoms; R ₇ represents an alkoxy group having 1 to 10 carbon atoms.

In the liquid crystal composition of the present invention, preferably, the compound represented by the aforementioned formula IV is preferably a group consisting of the compounds represented by the following formulas IV-1 to IV-2,

The liquid crystal composition of the present invention, preferably, the liquid crystal composition further contains a compound represented by formula V,

Wherein, R ₈ represents an alkyl group having 1 to 10 carbon atoms; R ₉ represents an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms.

The liquid crystal composition of the present invention, preferably, the liquid crystal composition further contains a compound represented by formula VI,

The liquid crystal composition of the present invention, preferably, the aforementioned liquid crystal composition also contains one or more compounds represented by formula VII,

表示

、

、

、

、

或

；e表示2或3，當存在多個

時，可相同或不同。 Wherein, R ₁₀ represents an alkyl group having 1 to 10 carbon atoms; R ₁₁ represents an alkoxy group having 1 to 10 carbon atoms;

express

,

,

,

,

or

;e means 2 or 3, when there are multiple

, can be the same or different.

In the liquid crystal composition of the present invention, preferably, the compound represented by the formula VII is selected from the group consisting of the compounds represented by the following formulas VII-1 to VII-4,

The liquid crystal composition of the present invention can preferably add antioxidants and hindered amine light stabilizers at a content of 0.01%-0.1%.

Preferably, the aforementioned antioxidant is selected from one of the antioxidants represented by formulas K-1 to K-4:

Wherein, s represents an integer with a carbon number of 1-5; preferably, the aforementioned hindered amine light stabilizer is one selected from the group consisting of hindered amine light stabilizers represented by formulas H-1 to H-2.

Among them, s represents an integer with a carbon number of 1-5.

The liquid crystal composition of the present invention preferably contains compounds represented by formulas I-1, I-2 and I-3, with a mass percentage of 5%-60%; and contains compounds represented by formulas II-1 and II. -2. Compounds represented by II-3 and II-4, with a mass percentage content of 1-8%; including compounds represented by formula III, with a mass percentage content of 1-12%; including compounds represented by formula IV, with a mass percentage content of 100% The content is 1-15%; it contains the compound represented by formula V, the mass percentage is 18-60%; it contains the compound represented by formula VI, the mass percentage is 1-10%; it contains the compound represented by formula VII, the mass percentage The percentage content is 1-10%.

Further preferably, the liquid crystal composition contains compounds represented by formulas I-1, I-2, and I-3, with a mass percentage of 40%-50%; and contains compounds represented by formulas II-1, II-2, and II-3. , the compound represented by II-4, the mass percentage content is 1-5%; it contains the compound represented by the formula III, the mass percentage content is 1-10%; it contains the compound represented by the formula IV, the mass percentage content is 1-12 %; contains the compound represented by formula V, the mass percentage content is 23-50%; contains the compound represented by formula VI, the mass percentage content is 1-8%; contains the compound represented by formula VII, the mass percentage content is 1- 6%.

[Liquid crystal display element or liquid crystal display]

The present invention also relates to a liquid crystal display element or a liquid crystal display comprising any one of the above 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 of the present invention is preferably an active matrix addressing liquid crystal display element or liquid crystal display.

Specific examples of the aforementioned active matrix display elements or displays include, for example, IPS-TFT or FFS-TFT or VA-TFT liquid crystal display elements or other TFT displays. IPS-TFT or FFS-TFT mode liquid crystal display elements or liquid crystal displays are particularly suitable.

The liquid crystal display element or liquid crystal display of the present invention contains the liquid crystal composition disclosed in the present invention. The liquid crystal display element or liquid crystal display of the present invention is mainly used in the field of large-size 8K liquid crystal display, and the liquid crystal display element has good picture display quality.

Example

In order to illustrate the present invention more clearly, the present invention will be further described below with reference to preferred embodiments. Those skilled in the art should understand that the content described below is illustrative rather than restrictive, and should not be used to limit the scope of the present invention.

In the present invention, the preparation methods are conventional methods unless otherwise specified. The raw materials used can be obtained from open commercial channels unless otherwise specified. The percentages refer to mass percentages. The temperature is in degrees Celsius (℃). The specific values of other symbols are The meaning and test conditions are as follows: Cp represents the clearing point of the liquid crystal (℃), tested by DSC quantitative method; △n represents the optical anisotropy, △n=n _e -n _o , where n _o is the refractive index of ordinary light, n _e is the refractive index of extraordinary light, the test conditions are 25±2℃, 589nm, Abbe refractometer test; △ε represents dielectric anisotropy, △ε=ε _∥ -ε _⊥ , where ε _∥ is parallel to the molecule The dielectric constant of the axis, ε _⊥ is the dielectric constant perpendicular to the molecular axis, the test conditions are 25±0.5℃, 20 micron anti-parallel box, INSTEC: ALCT-IR1 test; γ ₁ represents the rotational viscosity (mPa.s), The test conditions are 25±0.5℃, 20 micron anti-parallel box, INSTEC: ALCT-IR1 test; K11 is the splay elastic constant, K33 is the bending elastic constant, the test conditions are: 25℃, INSTEC: ALCT-IR1, 20 micron anti-parallel box Parallel box; VHR represents the voltage retention rate (%), the test conditions are 60±1℃, the voltage is ±5V, the pulse width is 10ms, and the voltage holding time is 166.7ms. The test equipment is the TOYO Model 6254 comprehensive liquid crystal performance tester; the alignment force represents the energy that needs to be overcome at the interface between the liquid crystal mixture and the alignment layer to cause the pointing arrows of the liquid crystal molecules to deviate from the direction of the easy alignment axis. The alignment force is characterized by measuring the difference in minimum brightness under different voltages before and after aging. The test conditions are room temperature and the voltage is the voltage under L127 gray scale conditions. Test equipment CA310.

Low-temperature observation conditions: Pour 1g of liquid crystal into a 5ml clean glass vial, seal it and place it in a -20°C low-temperature refrigerator. After 240 hours, observe whether the liquid crystal crystallizes.

The preparation method of the liquid crystal composition is as follows: weigh each liquid crystal monomer according to a certain ratio and put it into a stainless steel beaker. Place the stainless steel beaker containing each liquid crystal monomer on a magnetic stirring instrument and add Heat and melt. After most of the liquid crystal monomer in the stainless steel beaker is melted, add a magnetic rotor to the stainless steel beaker, stir the mixture evenly, and cool to room temperature to obtain the liquid crystal composition.

The liquid crystal monomer structure in the embodiment of the present invention is represented by a code. The code representation method of the liquid crystal ring structure, terminal group, and connecting group is shown in Table 1 and Table 2 below.

，其代碼為CC-Cp-V1；

，其代碼為PPY-3-O2；

，其代碼為CPY-2-O2；

，其代碼為CCY-3-O2；

，其代碼為COY-3-O2；

，其代碼為CCOY-3-O2；

，其代碼為CLY-3-O2；

，其代碼為Sb-CpO-O4；

，其代碼為Sc-CpO-O4；

，其代碼為PGP-Cpr1-2；

，其代碼為CCU-3-F；

，其代碼為PUQY-3-O2。 Example:

, its code is CC-Cp-V1;

, its code is PPY-3-O2;

, its code is CPY-2-O2;

, its code is CCY-3-O2;

, its code is COY-3-O2;

, its code is CCOY-3-O2;

, its code is CLY-3-O2;

, its code is Sb-CpO-O4;

, its code is Sc-CpO-O4;

, its code is PGP-Cpr1-2;

, its code is CCU-3-F;

, its code is PUQY-3-O2.

The following specific examples are used to illustrate the invention:

Example

Example 1

The formula and corresponding properties of the liquid crystal composition are shown in Table 3 below.

Table 3 Formulas and corresponding properties of the liquid crystal composition of Example 1

Comparative example 1

The formula and corresponding properties of the liquid crystal composition are shown in Table 4 below.

Comparative example 2

The formula and corresponding properties of the liquid crystal composition are shown in Table 5 below.

Comparative example 3

The formula and corresponding properties of the liquid crystal composition are shown in Table 6 below.

Comparative example 4

The formula and corresponding properties of the liquid crystal composition are shown in Table 7 below.

Comparative example 5

The formula and corresponding properties of the liquid crystal composition are shown in Table 8 below.

Comparative example 6

The formula and corresponding properties of the liquid crystal composition are shown in Table 9 below.

Comparative example 7

The formula and corresponding properties of the liquid crystal composition are shown in Table 10 below.

Comparative example 8

The formula and corresponding properties of the liquid crystal composition are shown in Table 11 below.

Example 2

The formula and corresponding properties of the liquid crystal composition are shown in Table 12 below.

Example 3

The formula and corresponding properties of the liquid crystal composition are shown in Table 13 below.

Example 4

The formula and corresponding properties of the liquid crystal composition are shown in Table 14 below.

Example 5

The formula and corresponding properties of the liquid crystal composition are shown in Table 15 below.

Example 6

The formula and corresponding properties of the liquid crystal composition are shown in Table 16 below.

Example 7

The formula and corresponding properties of the liquid crystal composition are shown in Table 17 below.

Example 8

The formula and corresponding properties of the liquid crystal composition are shown in Table 18 below.

Example 9

The formula and corresponding properties of the liquid crystal composition are shown in Table 19 below.

Example 10

The formula and corresponding properties of the liquid crystal composition are shown in Table 20 below.

Example 11

The formula and corresponding properties of the liquid crystal composition are shown in Table 21 below.

The alignment force represents the energy that needs to be overcome at the interface between the liquid crystal composition and the alignment layer to cause the pointing arrows of the liquid crystal molecules to deviate from the direction of the easy alignment axis. Under the influence of the outside world, when the alignment force is strong, the orientation of the liquid crystal pointing arrow on the surface is always fixed, and the brightness will not change; when the alignment force is weak, the pointing arrow of the liquid crystal molecules at the interface deviates from the anchored easy orientation axis, that is, at the surface The liquid crystal molecules rotate at a certain angle, causing the brightness to change.

The liquid crystal compositions in the examples and comparative examples were respectively poured into test boxes for testing. The test conditions were room temperature, L127 gray scale, and the DC bias voltage was ±0.3V; the test equipment was CA 310. Initially, test the brightness under different DC bias voltages under the L127 gray scale. The lowest point brightness is recorded as Lv1. After aging for 1 hour using 10V AC power, return to the L127 gray scale and test the brightness under different DC bias voltages again. At this time, the lowest point brightness is recorded as Lv2, and the strength of the alignment force can be expressed by △Tr, △Tr=(Lv2-Lv1)/Lv1*100%. The smaller ΔTr is, the better the alignment force of the liquid crystal is.

Pour 1g of liquid crystal from the liquid crystal compositions of the Examples and Comparative Examples into a 5ml clean glass vial, seal it and place it in a -20°C low-temperature refrigerator. After leaving it for 240 hours, observe whether there is crystal precipitation in the liquid crystal.

Voltage Holding Ratio (VHR) represents the voltage holding ratio (%) of the liquid crystal molecules of the liquid crystal composition after sensing the applied external voltage. The liquid crystal compositions of the examples and comparative examples were respectively poured into test boxes for testing. The test conditions are: 60℃, voltage of ±5V, pulse width of 10ms, voltage holding time of 166.7ms; the test equipment is TOYO Model 6254 liquid crystal performance comprehensive tester; the higher the test value of VHR, the better the voltage holding ability of the liquid crystal, which is applied to liquid crystal displays After the panel is installed, the smaller the voltage fluctuation of the liquid crystal material on a single TFT picture element is, the better the display quality will be.

Corresponding to the experimental data results shown in Table 22, it can be clearly understood that Example 1, which contains both the compound represented by formula I and the compound represented by formula II, has a similar composition but does not have the compound represented by formula I or the compound represented by formula II. The comparative example has higher alignment force (smaller △Tr), and also has better crystallization and VHR performance. It shows that the combined structure of the present invention including the compound represented by formula I and the compound represented by formula II can achieve high clearing point, large refractive index, good mutual solubility, especially strong alignment force, and can effectively improve the display In-plane and edge stains, especially suitable for large-size LCD displays.

Obviously, the above-mentioned embodiments of the present invention are only examples to clearly illustrate the present invention, and are not intended to limit the implementation of the present invention. For those of ordinary skill in the art, based on the above description, they can also make There are other different forms of changes or modifications, and it is impossible to exhaustively enumerate all the embodiments here. All obvious changes or modifications derived from the technical solution of the present invention are still within the protection scope of the present invention.

Claims (4)

A liquid crystal composition comprising one or more compounds represented by formula I, one or more compounds represented by formula II, one or more compounds represented by formula III, one or more compounds represented by formula IV, one or more compounds represented by formula V Compounds, compounds represented by formula VI, one or more compounds represented by formula VII,

Among them, R ₁ represents an alkenyl group with a carbon number of 2-10; R ₂ represents an alkoxy group with a carbon number of 1-10; R ₃ represents an alkyl group with a carbon number of 1-10; Z ₁ represents a single bond or -CH ₂ O-;

express

,

or

;

,

represent each independently

,

,

or

; m represents 1 or 2; when m represents 2, two consecutive

Can be the same or different; n represents 0 or 1; R ₄ and R ₅ each independently represent an alkyl group with a carbon number of 1-10; R ₆ represents an alkyl group with a carbon number of 1-10; R ₇ represents a carbon atom Alkoxy group with a number of 1-10; R ₈ represents an alkyl group with a carbon number of 1-10; R ₉ represents an alkyl group with a carbon number of 1-10 or an alkenyl group with a carbon number of 2-10; R ₁₀ represents an alkyl group having 1 to 10 carbon atoms; R ₁₁ represents an alkoxy group having 1 to 10 carbon atoms;

express

,

,

,

,

or

;e means 2 or 3, and multiple consecutive

Can be the same or different. The liquid crystal composition according to claim 1, wherein the compound represented by formula I in the liquid crystal composition is selected from the group consisting of the compounds represented by the following formulas I-1 to I-3,

Wherein, R ₁ represents an alkenyl group having 2 to 10 carbon atoms; R ₂ represents an alkoxy group having 1 to 10 carbon atoms. A liquid crystal display element, comprising the liquid crystal composition described in claim 1 or 2, wherein the liquid crystal display element is an active matrix display element or a passive matrix display element. A liquid crystal display comprising the liquid crystal composition described in claim 1 or 2, wherein the liquid crystal display is an active matrix display or a passive matrix display.