Liquid crystal composition, liquid crystal display element, or liquid crystal display

Abstract

The application belongs to the technical field of liquid crystal materials, and particularly relates to a liquid crystal composition and a liquid crystal display element or a liquid crystal display containing the liquid crystal composition. The application discloses a polymer-stabilized complex liquid crystal composition, characterized in that the liquid crystal composition contains one or more compounds shown in formula I, one or more compounds shown in formula II, at least one of compounds shown in formula S-1 and S-2, and at least one polymerizable compound:

Description

Technical Field

[0001] This invention belongs to the field of liquid crystal material technology, specifically relating to a polymer-stabilized liquid crystal composition and a liquid crystal display element or liquid crystal display containing the liquid crystal composition. Background Technology

[0002] In recent years, with the continuous progress and development of science and technology, liquid crystal display (LCD) technology has attracted great attention. Compared with traditional display technologies, TFT-LCD not only has many advantages such as small size, light weight, low power consumption, and easy driving, but also effectively makes up for the shortcomings of traditional display technologies. It is widely used in various consumer electronic products such as mobile phones, televisions, digital cameras, laptops, and desktop computers.

[0003] There are many display modes for TFT-LCDs, such as TN-TFT, IPS-TFT, VA-TFT, and PSVA-TFT. Among them, PSVA-TFT offers advantages such as high contrast and wide viewing angle. PSVA technology stands for Polymer Stabilized Vertically Aligned. This technology mainly uses TFT / ITO electrodes with gaps to control the tilt of the liquid crystal, and adds photosensitive polymers to the liquid crystal material. After the panel is assembled, an electric field is applied to tilt the liquid crystal, and ultraviolet light is used to react the photosensitive monomers within the liquid crystal, causing the liquid crystal to generate a pretilt angle according to the direction of the electric field, achieving multi-domain characteristics. Compared to MVA / PVA technology, PSVA has advantages such as excellent black state, fast response time, high transmittance, and low cost. PSVA technology often uses polyimide (PI) as the alignment film, but the fabrication process of PI alignment film is very time-consuming and has uncertain defects, which hinders the development of new technologies, such as limiting the frame design of the liquid crystal cell. In recent years, a new display technology mode has emerged in the market—SAVA (Self-alignment vertical alignment mode) technology (also called PI-less). This technology is similar to PSVA technology. It requires the addition of self-aligning agent liquid crystal materials to the liquid crystal to make the liquid crystals uniformly aligned in the display. This technology can save the complex PI manufacturing process and the cost of purchasing PI, thereby achieving the goal of reducing production costs and improving performance.

[0004] As people's living standards continue to improve, their demands for display effects are also increasing. 4K and 8K monitors have emerged one after another. 4K and 8K monitors can display more information in the picture. Whether it is fonts, skin tones, or details of people in the picture, they will be displayed more clearly. This puts forward higher requirements for the resolution, response time, and transmittance of the monitor.

[0005] In summary, SAVA technology and high-definition display technologies such as 8K have many advantages. However, the formation of the pretilt angle in SAVA technology requires the selection of appropriate UV1 and UV2 processes. Moreover, the combination of self-aligning agents and RM, as well as the selection of liquid crystal monomers, directly affect the final liquid crystal performance. How to use SAVA technology in combination with fast-response and high-transmittance liquid crystal formulations to provide high-quality picture effects has become an urgent problem to be solved for SAVA displays. Summary of the Invention

[0006] In order to solve the above-mentioned technical problems, the inventors conducted in-depth research and a large number of experiments and found that the technical solution of the present invention has a better pretilt angle, fast response, high transmittance and good reliability.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] This invention provides a polymer-stabilized liquid crystal composition, preferably comprising at least one compound of formula I, at least one compound of formula II, at least one compound of formulas S-1 and S-2, and at least one polymerizable compound:

[0009]

[0010] in,

[0011] R1, R3, and R0 each independently represent alkyl groups having 1-5 carbon atoms;

[0012] R2 represents an alkenyl group with 2-5 carbon atoms;

[0013] R4 represents an alkoxy group with 1-5 carbon atoms;

[0014] X1 and X2 each independently represent alkylene groups with 3-9 carbon atoms.

[0015] A second object of the present invention is to provide a liquid crystal display element comprising the liquid crystal composition of the present invention, wherein the liquid crystal display element is an active matrix addressing display element or a passive matrix addressing display element.

[0016] A third object of the present invention is to provide a liquid crystal display comprising the liquid crystal composition of the present invention, wherein the liquid crystal display is an active matrix addressing display or a passive matrix addressing display.

[0017] Invention Effects

[0018] The liquid crystal composition of the present invention can form a better pretilt angle and has good reliability. It can be used to develop liquid crystal display elements or liquid crystal displays with fast response, high transmittance and good reliability, and is especially suitable for liquid crystal display elements or liquid crystal displays with curved surfaces. Detailed Implementation

[0019] [Liquid Crystal Composition]

[0020] This invention provides a polymer-stabilized liquid crystal composition, preferably comprising at least one compound of formula I, at least one compound of formula II, at least one compound of formulas S-1 and S-2, and at least one polymerizable compound:

[0021]

[0022] in,

[0023] R1, R3, and R0 each independently represent alkyl groups having 1-5 carbon atoms;

[0024] R2 represents an alkenyl group with 2-5 carbon atoms;

[0025] R4 represents an alkoxy group with 1-5 carbon atoms;

[0026] X1 and X2 each independently represent alkylene groups with 3-9 carbon atoms.

[0027] Preferably, in the liquid crystal composition of the present invention, the compound represented by Formula I is selected from the group consisting of compounds represented by Formulas I-1 to I-2 below:

[0028]

[0029] Preferably, in the liquid crystal composition of the present invention, the compound represented by Formula II is selected from the group consisting of compounds represented by Formulas II-1 to II-4:

[0030]

[0031] Preferably, in the liquid crystal composition of the present invention, the compound represented by formula S-1 is selected from the group consisting of compounds represented by formulas S-1-1 to S-1-2:

[0032]

[0033] Preferably, in the liquid crystal composition of the present invention, the compound represented by formula S-2 is selected from the group consisting of compounds represented by formulas S-2-1 to S-2-2:

[0034]

[0035] In the liquid crystal composition of the present invention, preferably, the amount of the compounds shown in S-1 and / or S-2 above is added in addition to the total mass percentage of the liquid crystal composition by 0.1-1%, particularly 0.75-1%.

[0036] Preferably, in the liquid crystal composition of the present invention, the aforementioned polymerizable compound is selected from the group consisting of compounds represented by the following formulas RM-1 to RM-3:

[0037]

[0038] Preferably, in the liquid crystal composition of the present invention, the aforementioned polymerizable compound is added in an amount of 0.1-0.5%, particularly 0.35-0.45%, in addition to the total mass percentage of the liquid crystal composition.

[0039] The liquid crystal composition of the present invention preferably further comprises one or more compounds of formula III:

[0040]

[0041] in,

[0042] R5 and R6 each independently represent an alkyl group with 1-10 carbon atoms, an alkenyl group with 2-10 carbon atoms, or an alkoxy group with 1-10 carbon atoms.

[0043] Preferably, in the liquid crystal composition of the present invention, the compound represented by Formula III is selected from the group consisting of compounds represented by Formulas III-1 to III-4:

[0044]

[0045]

[0046] The liquid crystal composition of the present invention preferably further comprises one or more compounds of formula IV:

[0047]

[0048] in,

[0049] R7 and R8 each independently represent an alkyl group or an alkoxy group with 1-10 carbon atoms.

[0050] Preferably, in the liquid crystal composition of the present invention, the compound represented by Formula IV is selected from the group consisting of compounds represented by Formulas IV-1 to IV-4:

[0051]

[0052] The liquid crystal composition of the present invention preferably further comprises one or more compounds of formula V:

[0053]

[0054] in,

[0055] R9, R 10 Each can be independently represented as an alkyl group having 1-10 carbon atoms, an alkenyl group having 2-10 carbon atoms, or an alkoxy group having 1-10 carbon atoms;

[0056] express

[0057] Preferably, in the liquid crystal composition of the present invention, the compound represented by Formula V is selected from the group consisting of compounds represented by Formulas V-1 to V-8:

[0058]

[0059] The liquid crystal composition of the present invention preferably further comprises one or more compounds of formula VI:

[0060]

[0061] in,

[0062] R 11 R 12 Each can independently represent an alkyl group having 1-10 carbon atoms or an alkoxy group having 1-10 carbon atoms;

[0063] n represents 1 or 2.

[0064] Preferably, in the liquid crystal composition of the present invention, the compound represented by Formula VI is selected from the group consisting of compounds represented by Formulas VI-1 to VI-4:

[0065]

[0066] The liquid crystal composition of the present invention preferably further comprises one or more compounds represented by formula VII:

[0067]

[0068] in,

[0069] R 13 R 14 Each can be independently represented as an alkyl group having 1-10 carbon atoms or an alkoxy group having 1-10 carbon atoms.

[0070] Preferably, in the liquid crystal composition of the present invention, the compound represented by formula VII is selected from the group consisting of compounds represented by formulas VII-1 to VII-3:

[0071]

[0072] The liquid crystal composition of the present invention preferably further comprises one or more compounds of formula VIII:

[0073]

[0074] in,

[0075] R 15 Indicates alkoxy groups with 1-5 carbon atoms or

[0076] R 16 This indicates an alkyl group having 1-5 carbon atoms.

[0077] Preferably, in the liquid crystal composition of the present invention, the compound represented by Formula VIII is selected from the compound represented by Formula VIII-1 below:

[0078]

[0079] The liquid crystal composition of the present invention preferably further comprises a compound of formula IX:

[0080]

[0081] Various functional dopants can also be added to the liquid crystal compound of the present invention. The dopant content is preferably between 0.01% and 1%. Examples of such dopants include antioxidants, ultraviolet absorbers, and chiral agents.

[0082] Antioxidants can be listed as follows:

[0083]

[0084] Where t represents an integer from 1 to 10;

[0085] Chiral agents (levorotatory or dextrorotatory) are preferably exemplified by:

[0086]

[0087] [Liquid crystal display element or liquid crystal display]

[0088] The present invention also relates to a liquid crystal display element or liquid crystal display comprising any of the above-described liquid crystal compositions; the display element or display is an active matrix display element or display or a passive matrix display element or display.

[0089] 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.

[0090] The aforementioned active matrix display elements or displays can be specifically exemplified by, for example, IPS-TFT, FFS-TFT, or VA-TFT liquid crystal display elements or other TFT displays, especially SAVA-TFT mode liquid crystal display elements or liquid crystal displays.

[0091] The liquid crystal display element or liquid crystal display of the present invention comprises the liquid crystal composition disclosed herein. The liquid crystal display element or liquid crystal display of the present invention has high reliability, fast response speed, and good transmittance, and is mainly used in SAVA display modes, especially suitable for curved display elements or displays.

[0092] Example

[0093] To more clearly illustrate the present invention, the following description, in conjunction with preferred embodiments, further clarifies the invention. Those skilled in the art should understand that the specific descriptions below are illustrative rather than restrictive, and should not be construed as limiting the scope of protection of the present invention.

[0094] Unless otherwise specified, percentages in this instruction manual refer to mass percentages, temperatures are in degrees Celsius (°C), and the specific meanings and test conditions of other symbols are as follows:

[0095] Cp represents the liquid crystal clearing point (°C), measured by DSC quantitative method;

[0096] Δn represents optical anisotropy, n o Let n be the refractive index of ordinary light. e The refractive index of unusual light was measured at 25±2℃, 589nm, using an Abbe refractometer.

[0097] Δε represents dielectric anisotropy, Δε = ε ∥ -ε ⊥ , where ε ∥ ε is the dielectric constant parallel to the molecular axis. ⊥ The dielectric constant is perpendicular to the molecular axis. The test conditions are 25±0.5℃, 20-micron vertical cell, and INSTEC:ALCT-IR1 test.

[0098] K 11 K is the elastic constant of the development. 22 K is the torsional elastic constant. 33 The bending elastic constant was determined under the following test conditions: 25°C, INSTEC:ALCT-IR1, and a 20-micron vertical box.

[0099] Tr(%) represents transmittance. T(%) = 100% * bright state (Vop) luminance / light source luminance. The test equipment is DMS505, the test conditions are 25±0.5℃, the test box is a 3.2-micron SAVA test box, and the electrode spacing and electrode width are both 5 microns.

[0100] Pre-tilt angle (°), test conditions are 25±0.5℃, SAVA test box, machine tilt angle 45°, test equipment RETS-1000;

[0101] VHR represents the voltage hold-up rate (%). The test conditions were 60±1℃, ±5V, pulse width 10ms, and voltage hold-up time 1.667ms. The test equipment was a TOYO Model 6254 LCD performance comprehensive tester.

[0102] Backlight aging conditions: backlight intensity 12000nit, aging temperature 60±1℃, and applied voltage AC 7V.

[0103] RT represents the response time (ms). The test instrument is DMS-501, the test conditions are 25±0.5℃, the test box is a 3.3-micron PSVA test box, and the electrode spacing and electrode width are both 5 microns.

[0104] 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 stirrer and heat it to melt. After most of the liquid crystal monomer in the stainless steel beaker has melted, add a magnetic rotor to the stainless steel beaker and stir the mixture evenly. After cooling to room temperature, the liquid crystal composition is obtained.

[0105] The method for fabricating the liquid crystal display device in the embodiments of the present invention is as follows: First, an alignment material, such as polyimide, is uniformly coated on the surfaces of a first substrate and a second substrate. The uniformly coated alignment material is then heated and cured at 230°C to form an alignment layer. Second, spacers are dispersed on the surface of the second substrate, and a border adhesive is applied along the edge of the first substrate and cured at 120°C. Then, the first substrate and the second substrate are placed opposite each other and bonded together to form a structure with a sandwich space. Finally, a liquid crystal composition is injected into the sandwich space between the first substrate and the second substrate, and sealed and cured, thereby sealing the liquid crystal composition between the first substrate and the second substrate, while simultaneously applying electricity and irradiating with ultraviolet light. The ultraviolet light irradiation is divided into two stages, including a first stage of ultraviolet light irradiation (UV1) and a second stage of ultraviolet light irradiation (UV2). The duration of UV1 is directly related to the size of the pretilt angle, so different alignment agents and RM contents require different UV1 times.

[0106] The liquid crystal monomer structure in the embodiments of the present invention is represented by code. The code representation methods of liquid crystal ring structure, end group and linking group are shown in Table 1 and Table 2 below.

[0107] Table 1. Corresponding codes for ring structures

[0108]

[0109] Table 2. Correspondence codes between end groups and linking groups

[0110]

[0111]

[0112] For example:

[0113] Its code is PPY-3-O2;

[0114] Its code is CPY-2-O2;

[0115] Its code is CCY-3-O2;

[0116] Its code is COY-3-O2;

[0117] Its code is CCOY-3-O2;

[0118] Its code is CLY-3-O2;

[0119] Its code is Sb-CpO-O4;

[0120] Its code is Sc-CpO-O4.

[0121] Composition Example 1 (M1)

[0122] The formulations and corresponding properties of the liquid crystal compositions are shown in Table 3 below.

[0123] Table 3 Formulations and corresponding properties of M1 liquid crystal compositions

[0124]

[0125] Composition Example 2 (M2)

[0126] The formulations and corresponding properties of the liquid crystal compositions are shown in Table 4 below.

[0127] Table 4 Formulations and corresponding properties of M2 liquid crystal compositions

[0128]

[0129] Composition Example 3 (M3)

[0130] The formulations and corresponding properties of the liquid crystal compositions are shown in Table 5 below.

[0131] Table 5 Formulations and corresponding properties of M3 liquid crystal compositions

[0132]

[0133]

[0134] Composition Example 4 (M4)

[0135] The formulations and corresponding properties of the liquid crystal compositions are shown in Table 6 below.

[0136] Table 6 Formulations and corresponding properties of M4 liquid crystal compositions

[0137]

[0138]

[0139] Comparative Example 1 (D1) of Compositions

[0140] The formulations and corresponding properties of the liquid crystal compositions are shown in Table 7 below.

[0141] Table 7 Formulations and corresponding properties of D1 liquid crystal compositions

[0142]

[0143] Comparative Example 2 (D2) of Composition

[0144] The formulations and corresponding properties of the liquid crystal compositions are shown in Table 8 below.

[0145] Table 8 Formulations and corresponding properties of D2 liquid crystal compositions

[0146]

[0147]

[0148] Comparative Example 3 (D3)

[0149] The formulations and corresponding properties of the liquid crystal compositions are shown in Table 9 below.

[0150] Table 9 Formulations and corresponding properties of D3 liquid crystal compositions

[0151]

[0152]

[0153]

[0154] Table 10. Pretilt angle, response time, and transmittance of liquid crystal compositions

[0155]

[0156]

[0157] Note: — indicates no alignment, and corresponding data cannot be tested. The smaller the RT response time value (ms), the faster the response and the better the performance; the larger the Tr (%) transmittance, the better the performance.

[0158] Table 11 Reliability test data of liquid crystal compositions

[0159]

[0160] The reliability of the liquid crystal composition was assessed through UV and high-temperature aging tests, followed by VHR (Vibration Resistance) testing. The smaller the change in VHR data before and after UV aging, the stronger the UV resistance. First, the VHR data of the liquid crystal composition was measured as initial VHR data before the UV aging test. Then, the liquid crystal composition underwent the UV aging test, and the VHR data was measured again afterward. UV Aging Test: The liquid crystal composition was placed under a 365nm UV lamp and irradiated with 5000mJ of energy. The smaller the change in VHR data after the aging test compared to the initial VHR data, the stronger the UV resistance of the liquid crystal composition. This indicates a higher reliability and stronger resistance to environmental damage during operation.

[0161] Compared with Comparative Examples 1-3 and the Example, Comparative Example 1 has too low a refractive index, resulting in slow response and low transmittance; Comparative Example 2 has a moderate refractive index, but a small pretilt angle, resulting in poor reliability; Comparative Example 3 has a small pretilt angle, low transmittance, and poor reliability.

[0162] Compared with Comparative Examples 4-7 and the Example, Comparative Example 4 did not add RM, so no pretilt angle was formed in the liquid crystal display. During display driving, the rotation direction of liquid crystal molecules was disordered, resulting in a slow response. Comparative Example 5 did not add alignment agent, so the liquid crystal could not be aligned in the display, and the panel could not display normally. Although Comparative Examples 6 and 7 could form alignment and pretilt angle, the pretilt angle formed after the alignment agent and RM were combined was too small, resulting in low transmittance and poor reliability.

[0163] In summary, the liquid crystal composition of the present invention can form a better pretilt angle and has good reliability, and can be used to develop liquid crystal display elements or liquid crystal displays with fast response, high transmittance and good reliability, especially suitable for liquid crystal display elements or liquid crystal displays with curved surfaces.

[0164] The above embodiments disclosed in this invention are merely examples for clearly illustrating the invention, and are not intended to limit the implementation of the invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all implementation methods here. All obvious variations or modifications derived from the technical solutions of this invention are still within the protection scope of this invention.

Claims

1. A polymer-stabilized cholesteric liquid crystal composition, characterized in that, The liquid crystal composition comprises one or more compounds represented by Formula I, one or more compounds represented by Formula II, one or more compounds represented by Formula III, an additive amount of 0.75 to 1% of a compound represented by Formula S-1-1, and at least one polymerizable compound selected from the group consisting of compounds represented by Formulas RM-1 and RM-2: wherein, R1 and R3 each independently represent an alkyl group having 1 to 5 carbon atoms; R2 represents an alkenyl group having 2 to 5 carbon atoms; R4 represents an alkoxy group having 1 to 5 carbon atoms; R5 and R6 each independently represent an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or an alkoxy group having 1 to 10 carbon atoms.

2. The liquid crystal composition according to claim 1, characterized by The liquid crystal composition further comprises one or more compounds represented by Formula IV: wherein, R7 and R8 each independently represent an alkyl group having 1 to 10 carbon atoms or an alkoxy group having 1 to 10 carbon atoms.

3. The liquid crystal composition according to claim 2, characterized by The liquid crystal composition further comprises one or more compounds represented by Formula V: wherein, R9, R 10 each independently represents an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or an alkoxy group having 1 to 10 carbon atoms; denotes 4. The liquid crystal composition according to claim 3, characterized by The liquid crystal composition further comprises one or more compounds represented by Formula VI: wherein, R 11 , R 12 each independently represents an alkyl group having 1 to 10 carbon atoms or an alkoxy group having 1 to 10 carbon atoms; n represents 1 or 2.

5. The liquid crystal composition according to claim 4, characterized by The liquid crystal composition further comprises one or more compounds represented by Formula VII: wherein, R 13 , R 14 each independently represents an alkyl group having 1 to 10 carbon atoms or an alkoxy group having 1 to 10 carbon atoms.

6. The liquid crystal composition according to claim 5, characterized by The liquid crystal composition further comprises one or more compounds represented by Formula VIII: wherein, R 15 represents an alkoxy group having a carbon number of 1 to 5 or R 16 represents an alkyl group having 1 to 5 carbon atoms.

7. A liquid crystal display device, characterized by comprising: The liquid crystal display comprises the liquid crystal composition according to any one of claims 1 to 6, and is an active matrix addressing display or a passive matrix addressing display.

8. A liquid crystal display element, characterized by comprising: The liquid crystal display element comprises the liquid crystal composition according to any one of claims 1 to 6, and is an active matrix addressing display element or a passive matrix addressing display element.

9. The liquid crystal display element according to claim 8, wherein The active matrix addressing display element is a SAVA display mode.

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