CN116656379A - A dichroic dye composition, and a dye liquid crystal mixture comprising it - Google Patents

Abstract

The invention belongs to the technical field of liquid crystal materials, and particularly relates to a dichroism dye composition and a dye liquid crystal mixture containing the dichroism dye composition. The dichroism dye composition comprises at least one dichroism dye represented by a general formula I, at least one dichroism dye represented by a general formula II, at least one dichroism dye represented by a general formula III and at least one dichroism dye represented by a general formula IV. The dichroic dye composition can absorb all visible light and part of ultraviolet and near infrared light. The dye liquid crystal mixture comprises the dichromatic dye composition as a guest and a liquid crystal composition as a host, wherein the liquid crystal composition has low dispersion coefficient and lower viscosity, the solubility of the dichromatic dye composition is high, the photo-thermal stability of the obtained dye liquid crystal mixture is good, and the dye liquid crystal mixture shows high brightness and darkness contrast when applied to VA type liquid crystal devices.

Description

A dichroic dye composition and a dye liquid crystal mixture containing the same

Technical Field

The invention belongs to the technical field of liquid crystal materials, and in particular relates to a dichroic dye composition and a dye liquid crystal mixture containing the same.

Background Art

Liquid crystals are used in particular as dielectrics in display devices, taking advantage of the fact that the optical properties of such substances can be influenced by the action of an electric field they experience. Electro-optical devices based on liquid crystals are well known to those skilled in the art and can be based on a variety of effects. Devices of this type are, for example, cells with dynamic scattering, DAP (deformation of alignment phase) cells, TN cells with twisted nematic structures, STN ("super twisted nematic") cells, SBE ("super birefringence effect") cells, OMI ("optical mode interference") cells and guest-host cells.

Devices based on the guest-host effect were first described by Heilmeier and Zanoni (G. H. Heilmeier et al., Appl. Phys. Lett., 1968, 13, 91f) and have been widely used since then, mainly in liquid crystal display elements.

The prior art discloses a liquid crystal medium for a guest-host type display element, which includes a cyanobiphenyl derivative and one or more dichroic dyes (WO2009/141295 and WO2010/118422). For the same application, the prior art discloses a liquid crystal mixture containing one or more tricyclic compounds having two or more fluorine substituents and one or more dichroic dyes. The compound is used in a guest-host type LC device (US6033598 and US5762824).

However, there continues to be interest in new liquid crystal mixtures containing one or more dichroic dyes. In particular, there is a need for mixtures in which the dichroic dyes are easily soluble and can be stored in solution for a long time. In particular, there continues to be a need for mixtures that are stable to light and electric fields for a long time. There also continues to be a need for mixtures in which the dichroic dyes have a high degree of anisotropy, i.e., good alignment with the molecules of the liquid crystal mixture. There also continues to be a need for mixtures with high bright spots and high and low temperature stability.

Summary of the invention

The present invention aims to provide a novel dichroic dye composition having at least one, preferably several, of the following desirable properties: good solubility of the dye in liquid crystal media, good photothermal stability, and high absorption anisotropy, i.e., high ability of the dye to align with the liquid crystal. In addition, the dye should have strong light absorption in the VIS and NIR of light.

Surprisingly, it has been found that the dichroic dye compositions according to the invention and dye liquid crystal mixtures comprising at least one bicyclic cyano compound, at least one tricyclic cyano compound, at least one tetracyclic or polycyclic compound achieve the present technical objectives.

The terms bicyclic, tricyclic and polycyclic mean that the compound has two, three or more rings. The rings may be aromatic, heteroaromatic, aliphatic or heteroaliphatic.

Specifically, the dichroic dye composition of the present invention comprises at least one dichroic dye represented by general formula I, at least one dichroic dye represented by general formula II, at least one dichroic dye represented by general formula III, and at least one dichroic dye represented by general formula IV:

The general formula I is specifically:

The general formula II is specifically:

The general formula III is specifically:

The general formula IV is specifically:

wherein R ₁ -R ₁₀ each independently represent a straight chain or branched chain alkyl, alkenyl, alkoxy, alkenyloxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy group having 1 to 7 carbon atoms;

a ₁ -a ₃ , b ₁ -b ₃ each independently represent 0, 1 or 2;

Z ₁ to _{Z 6} each independently represent an ester group, a cyclohexyl group, a phenyl group, an ester phenyl group or a phenylcyclohexyl group.

In the present invention, dichroic dye refers to a light absorbing compound in which the absorption properties depend on the alignment of the compound with the polarization direction of light. The dichroic dye compound of the present invention generally has an elongated shape, similar to the shape of liquid crystal compounds, which is significantly longer in one spatial direction (longitudinal axis) than in the other two spatial directions.

Preferably, R ₄ , R ₅ , R ₇ , R ₈ and R ₁₀ represent substituents other than methyl; more preferably, one or more of R ₄ , R ₅ , R ₇ and R ₈ represent ethyl, and R 10 represents isobutyl or isopentyl.

Preferably, a ₁ -a ₃ , b ₁ -b ₃ independently represent 0 or 1.

Preferably, one or more of Z ₁ , Z ₄ , and Z ₆ represent a phenyl group.

Preferably, the general formula I is selected from one or more compounds of formula I-A-1 to I-B-3:

Preferably, the general formula Ⅱ is selected from one or more compounds of formula II-A-1 to II-B-3:

Preferably, the general formula III is selected from one or more compounds selected from formula III-A-1 to III-B-3:

Preferably, the general formula IV is selected from one or more compounds of formula IV-1 to IV-6:

The present invention also provides a dye liquid crystal mixture with negative dielectric anisotropy, wherein the dye liquid crystal mixture comprises the above-mentioned dichroic dye composition as a guest and a liquid crystal composition as a host. The liquid crystal composition as a host is preferably a nematic liquid crystal composition.

Specifically, the nematic liquid crystal composition includes at least one of the compounds represented by Formula V and at least one of the compounds represented by Formula VI;

Wherein, in the general formula V, R ₁₁ and R ₁₂ each independently represent a C ₁ ～C ₁₂ straight-chain alkyl group, a C ₁ ～C ₁₂ straight-chain alkoxy group or a C ₂ ～C ₁₂ straight-chain alkenyl group;

In the general formula VI, R ₁₃ and R ₁₄ each independently represent a C ₁ to C ₁₂ straight-chain alkyl group, a C ₁ to C ₁₂ straight-chain alkoxy group or a C ₂ to C ₁₂ straight-chain alkenyl group;

_Z7 represents _-CH2CH2- , -CH=CH-, _-CF2O- , _-OCF2- , -CH2O-, _-OCH2- , _{-CO -} O-, -O-CO-, _-C2F4- , _-CF =CF-, -CH=CH- _CH2O- or a single bond.

The liquid crystal composition provided by the present invention has a low dispersion coefficient, a low viscosity, and a high solubility for dyes. The dichroic dye composition provided by the present invention has good solubility in the liquid crystal composition, and the obtained dye liquid crystal mixture has good light and heat stability, and is applied to VA type liquid crystal devices to show high light-dark contrast.

As a preferred embodiment of the above technical solution, the compound represented by general formula V is selected from one or more of formula VA1 to formula VA16:

Further preferably, the compound represented by general formula V is selected from one or more of VA8, VA16, VIB14, and VIB16;

As a preferred embodiment of the above technical solution, the compound represented by general formula VI is selected from one or more of formulas VIA to VIB:

Wherein, R ₁₃ and R ₁₄ each independently represent a C ₁ -C ₇ straight-chain alkyl group, a C ₁ -C ₇ straight-chain alkoxy group or a C ₂ -C ₇ straight-chain alkenyl group.

Further preferably, the compound represented by general formula VI is selected from one or more of formula VIA1 to formula VIB16:

Most preferably, the compound represented by formula VI is selected from one or more of VIA8, VIA16, VIB6, and VIB14;

Further, the nematic liquid crystal composition comprises one or more of the compounds represented by the general formula VII;

Wherein, R ₁₅ and R ₁₆ each independently represent a C ₁ to C ₁₂ straight-chain alkyl group, a C ₁ to C ₁₂ straight-chain alkoxy group or a C ₂ to C ₁₂ straight-chain alkenyl group, Z ₈ may represent -CH ₂ CH ₂ -, -CH＝CH-, -CF ₂ O-, -OCF ₂ -, -CH ₂ O-, -OCH ₂ -, -CO-O-, -O-CO-, -C ₂ F ₄ -, -CF＝CF-, -CH＝CH-CH ₂ O- or a single bond, A ₁ represents trans-1,4-cyclohexyl or 1,4-phenylene, and a ₄ is 0 or 1.

Preferably, the compound represented by general formula VII is selected from one or more of formula VIIA to formula VIIC:

Wherein, R ₁₅ and R ₁₆ each independently represent a C ₁ to C ₇ straight-chain alkyl group, a C ₁ to C ₇ straight-chain alkoxy group or a C ₂ to C ₇ straight-chain alkenyl group, Z ₈ may represent -CH ₂ CH ₂ -, -CH ₂ O-, -CO-O-, -O-CO-, -CF＝CF-, -CH＝CH-CH ₂ O- or a single bond, A ₁ represents trans-1,4-cyclohexyl or 1,4-phenylene, and a ₄ is 0 or 1.

Further preferably, the compound represented by general formula VII is selected from one or more of formula VIIA1 to formula VIIC16:

Most preferably, the compound represented by general formula VII is selected from one or more of VIIA5-VIIA8, VIIA12-VIIA16, VIIB2, VIIB6, VIIB14, VIIC5-VIIC8.

Further, the nematic liquid crystal composition comprises one or more of the compounds represented by the general formula VIII;

In the general formula VIII, R ₁₇ and R ₁₈ each independently represent a C ₁ to C ₁₂ straight-chain alkyl group, a C ₁ to C ₁₂ straight-chain alkoxy group or a C ₂ to C ₁₂ straight-chain alkenyl group; A ₂ and A ₃ each independently represent a trans-1,4-cyclohexyl group or a 1,4-phenylene group.

Preferably, the compound represented by general formula VIII is selected from one or more of formula VIIIA to formula VIIIB:

Wherein, R ₁₇ and R ₁₈ each independently represent a C ₁ -C ₇ straight-chain alkyl group, a C ₁ -C ₇ straight-chain alkoxy group or a C ₂ -C ₇ straight-chain alkenyl group.

More preferably, the compound represented by general formula VIII is selected from one or more of formula VIIIA1 to formula VIIIB24:

Most preferably, the compound represented by general formula VIII is selected from one or more of VIIIA7, VIIIA11, VIIIA12, VIIIA21, VIIIB18, and VIIIB22.

Furthermore, the nematic liquid crystal composition comprises the following components in percentage by mass:

(1) 22 to 58% of the compound represented by the general formula V;

(2) 0 to 22% of a compound represented by Formula VI;

(3) 10 to 30% of the compound represented by the general formula VII;

(4), 10 to 40% of the compound represented by the general formula VIII;

Preferably, the nematic liquid crystal composition comprises the following components in percentage by mass:

(1) 25-55% of a compound represented by formula V;

(2) 0 to 20% of a compound represented by Formula VI;

(3) 12 to 28% of the compound represented by the general formula VII;

(4), 13 to 38% of the compound represented by the general formula VIII;

More preferably, the nematic liquid crystal composition comprises the following components in percentage by mass:

(1) 25-50% of a compound represented by formula V;

(2) 0 to 18% of a compound represented by Formula VI;

(3) 15-25% of the compound represented by the general formula VII;

(4) 16 to 35% of the compound represented by formula VIII;

Further preferably, the nematic liquid crystal composition comprises the following components in percentage by mass:

(1) 30-46% of the compound represented by the general formula V;

(2) 0 to 15% of a compound represented by Formula VI;

(3) 18 to 24% of the compound represented by the general formula VII;

(4) 19 to 32% of the compound represented by the general formula VIII.

The dye liquid crystal mixture provided by the present invention further comprises a chiral dopant. Table 1 shows chiral compounds preferably usable as chiral dopants in the dye liquid crystal mixture of the present invention.

Table 1: Chiral compounds

Preferably, based on the weight of the liquid crystal composition, the dye liquid crystal mixture contains 0.01 to 2% of the chiral compound, preferably 0.5 to 1.8%, more preferably 0.6 to 1.5%, and more preferably 0.66 to 1.5%.

In a preferred embodiment, based on the weight of the liquid crystal composition, the dye liquid crystal mixture comprises the following components in percentage by weight:

Serial number Components Weight percentage (%) 1 Liquid crystal composition 100 2 Dye Formula Ⅰ 0%～1.8% 3 Dye Formula Ⅱ 0%～3.0% 4 Dye formula III 0%～3.0% 5 Dye Formula IV 0%～4.0% 6 R/S811 0.01%～2.0%

As a preferred embodiment of the above technical solution, the dye liquid crystal mixture comprises the following components in percentage by mass:

Serial number Components Weight percentage (%) 1 Liquid crystal composition 100 2 Dye Formula Ⅰ 0.2%～1.2% 3 Dye Formula Ⅱ 0.3%～2.0% 4 Dye formula III 0.2%～2.5% 5 Dye Formula IV 1.3%～2.7% 6 R/S811 1.0%～1.8%

Further preferably, the dye liquid crystal mixture comprises the following components in percentage by mass:

More preferably, the dye liquid crystal mixture comprises the following components in percentage by mass:

Serial number Components Weight percentage (%) 1 Liquid crystal composition 100 2 Dye Formula Ⅰ 0.5%～0.9% 3 Dye Formula Ⅱ 0.44%～0.8% 4 Dye formula III 0.27%～0.5% 5 Dye Formula IV 1.39%～2.5% 6 R/S811 1.25%～1.5%.

In another preferred embodiment, based on the weight of the liquid crystal composition, the dye liquid crystal mixture may further include the following components in percentage by weight:

Serial number Components Weight percentage (%) 1 Liquid crystal composition 100 2 Dye Formula Ⅰ 0%～1.8% 3 Dye Formula Ⅱ 0%～3.0% 4 Dye formula III 0%～3.0% 5 Dye Formula IV 0%～4.0% 6 R/S2011 0.01%～2.0%

As a preferred embodiment of the above technical solution, the dye liquid crystal mixture comprises the following components in percentage by mass:

Serial number Components Weight percentage (%) 1 Liquid crystal composition 100 2 Dye Formula Ⅰ 0.2%～1.2% 3 Dye Formula Ⅱ 0.3%～2.0% 4 Dye formula III 0.2%～2.5% 5 Dye Formula IV 1.3%～2.7% 6 R/S2011 0.5%～1.8%

Further preferably, the dye liquid crystal mixture comprises the following components in percentage by mass:

More preferably, the dye liquid crystal mixture comprises the following components in percentage by mass:

Serial number Components Weight percentage (%) 1 Liquid crystal composition 100 2 Dye Formula Ⅰ 0.5%～0.9% 3 Dye Formula Ⅱ 0.44%～0.8% 4 Dye formula III 0.27%～0.5% 5 Dye Formula IV 1.39%～2.5% 6 R/S2011 0.66%～1.41%

The preparation method of the dye liquid crystal mixture of the present invention is not particularly limited, and can be produced by mixing two or more compounds in a conventional manner, such as by mixing different components at high temperature and dissolving them in each other.

The present invention also provides a device comprising the dye liquid crystal mixture, which can regulate the energy radiated by the sun from the external space (preferably an environment directly exposed to sunlight) to the internal space (a building or a vehicle) or another unit substantially isolated from the environment.

Preferably, the device directly or indirectly regulates the energy of solar radiation, specifically electromagnetic radiation in the UV-A, VIS and NIR regions. The UV-A region refers to the wavelength range of 320nm to 380nm, the VIS region refers to the wavelength range of 380nm to 780nm, and the NIR region refers to the wavelength range of 780nm to 2000nm.

Among the numerous technical solutions for regulating the passage of energy from the external space to the internal space, the use of switching layers containing dye-liquid crystal mixtures is advantageous. Due to their direction-dependent absorption, a change in the spatial orientation of the molecules of the dichroic compound can be achieved in these switching layers by applying a voltage, which causes a change in the transmission of the switching layer.

Preferably, the device is a VA liquid crystal box (twist angle 180°-360°) with a twisted-supertwisted nematic phase structure, which utilizes the omnidirectional arrangement of liquid crystal in a plane to achieve light absorption in all directions of natural light without the use of a polarizer, thereby realizing high brightness-dark contrast in applications.

DETAILED DESCRIPTION

The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

Unless otherwise specified, percentages in the present invention are weight percentages; temperatures are in degrees Celsius; △n represents optical anisotropy (25°C); △ε represents dielectric anisotropy (25°C, 1000 Hz); γ1 represents rotational viscosity (mPa.s, 25°C); and Cp represents the clearing point of the liquid crystal composition (°C).

In the following liquid crystal mixtures, the group structures in the liquid crystal compounds are represented by the codes shown in Table 2.

Table 2: Group structure codes of liquid crystal compounds

Take the following compound structure as an example:

Expressed as: 5CCEC2

Preparation of liquid crystal dye mixtures

Nematic LC host mixtures N-1 to N-4 were prepared as follows:

The weight percentages of the components in the liquid crystal compositions and the performance parameters of the liquid crystal compositions in the following nematic LC host mixtures are shown in the following table.

Mixture N-1

Table 3: Weight percentage and performance parameters of each component in the liquid crystal composition

Mixture N-2

Table 4: Weight percentage and performance parameters of each component in the liquid crystal composition

Mixture N-3

Table 5: Weight percentage and performance parameters of each component in the liquid crystal composition

Mixture N-4

Table 6: Weight percentage and performance parameters of each component in the liquid crystal composition

In the following examples, the weight percentages of dye monomers, chiral agents, antioxidants, and anti-ultraviolet additives are based on the weight of the nematic liquid crystal composition and are added separately in addition to the mass percentage of the nematic liquid crystal composition. Among them, the structural formula of the antioxidant is:

The structural formula of the anti-ultraviolet additive is:

Example 1

Table 7 Weight percentage and performance parameters of each component in the dye liquid crystal mixture

Mixture Code Weight percentage (%) N-1 100 Dye Ⅰ-A-1 0.9 Dye Ⅱ-B-3 0.8 Dye Ⅲ-A-2 0.5 Dye IV-1 1.2 Dye IV-3 1.3 R/S811 1.5 Antioxidants 0.03 Anti-ultraviolet additives 0.3

The dye liquid crystal mixture mentioned in Example 1 is black as a whole, and can absorb wavelengths in the entire visible light and part of the ultraviolet and near-infrared regions. In a liquid crystal cell with a cell thickness of 6-9 μm, the dark state transmittance can be as low as 8% or less. This dye liquid crystal mixture has a low dispersion coefficient, shows a high light-dark contrast in the application of VA-type liquid crystal devices, and has a low viscosity. The dye has good solubility in the liquid crystal medium N-1 and good light and heat stability. The glass transition temperature of this dye liquid crystal mixture is below 0°.

Example 2

Table 8 Weight percentage and performance parameters of each component in the dye liquid crystal mixture

Mixture Code Weight percentage (%) N-2 100 Dye Ⅰ-A-1 0.64 Dye Ⅱ-B-3 0.57 Dye Ⅲ-A-2 0.35 Dye IV-1 0.86 Dye IV-3 0.93 R/S811 1.25 Antioxidants 0.03 Anti-ultraviolet additives 0.3

The dye liquid crystal mixture mentioned in Example 2 is black as a whole, and can absorb wavelengths in the entire visible light and part of the ultraviolet and near-infrared regions. In a liquid crystal box with a cell thickness of 6-9 μm, the dark state transmittance can be as low as 10% or less. This dye liquid crystal mixture has a low dispersion coefficient, shows a high light-dark contrast in the application of VA-type liquid crystal devices, and has high-definition bright spots. The dye has good solubility in the liquid crystal medium N-2 and good light and thermal stability. The glass transition temperature of this dye liquid crystal mixture is below -20°, and the clearing point can reach 109°C.

Example 3

Table 9 Weight percentage and performance parameters of each component in the dye liquid crystal mixture

The dye liquid crystal mixture mentioned in Example 3 is black as a whole, and can absorb wavelengths in the entire visible light and part of the ultraviolet and near-infrared regions. In a liquid crystal box with a box thickness of 6-9 μm, the dark state transmittance can be as low as 10% or less. This dye liquid crystal mixture has a low dispersion coefficient. Compared with the liquid crystal mixture mentioned in Example 2, this liquid crystal mixture shows a higher light-dark contrast in the application of VA-type liquid crystal devices, and the dye has better solubility in the liquid crystal medium N-3 and good light and heat stability. The glass transition temperature of this dye liquid crystal mixture is below -20°.

Example 4

Table 10 Weight percentage and performance parameters of each component in the dye liquid crystal mixture

Mixture Code Weight percentage (%) N-4 100 Dye Ⅰ-A-1 0.50 Dye Ⅱ-B-3 0.44 Dye Ⅲ-A-2 0.27 Dye IV-1 0.67 Dye IV-3 0.72 R/S811 1.33 Antioxidants 0.03 Anti-ultraviolet additives 0.3

The dye liquid crystal mixture mentioned in Example 4 is black as a whole, and can absorb wavelengths ranging from all visible light and part of the ultraviolet and near-infrared regions. In a liquid crystal box with a box thickness of 6-9μm, the dark state transmittance can reach a minimum of less than 16%. This dye liquid crystal mixture has a low dispersion coefficient. Compared with the liquid crystal mixture mentioned in Example 3, this dye liquid crystal mixture shows a higher light-dark contrast in the application of VA-type liquid crystal devices. The solubility of the dye in the liquid crystal medium N-4 is not as good as N-3, and the light and heat stability is good. The glass transition temperature of this dye liquid crystal mixture is below -20°, and the clearing point can reach 110°.

Example 5

Table 11 Weight percentage and performance parameters of each component in the dye liquid crystal mixture

Example 6

Table 12 Weight percentage and performance parameters of each component in the dye liquid crystal mixture

Example 7

Table 13 Weight percentage and performance parameters of each component in the dye liquid crystal mixture

Example 8

Table 14 Weight percentage and performance parameters of each component in the dye liquid crystal mixture

Example 9

Table 15 Weight percentage and performance parameters of each component in the dye liquid crystal mixture

Example 10

Table 16 Weight percentage and performance parameters of each component in the dye liquid crystal mixture

Embodiment 11

Table 17 Weight percentage and performance parameters of each component in the dye liquid crystal mixture

Example 12

Table 18 Weight percentage and performance parameters of each component in the dye liquid crystal mixture

Example 13

Table 19 Weight percentage and performance parameters of each component in the dye liquid crystal mixture

Embodiment 14

Table 20 Weight percentage and performance parameters of each component in the dye liquid crystal mixture

Embodiment 15

Table 21 Weight percentage and performance parameters of each component in the dye liquid crystal mixture

Example 16

Table 22 Weight percentage and performance parameters of each component in the dye liquid crystal mixture

Embodiment 17

Table 23 Weight percentage and performance parameters of each component in the dye liquid crystal mixture

Embodiment 18

Table 24 Weight percentage and performance parameters of each component in the dye liquid crystal mixture

Embodiment 19

Table 25 Weight percentage and performance parameters of each component in the dye liquid crystal mixture

Embodiment 20

Table 26 Weight percentage and performance parameters of each component in the dye liquid crystal mixture

Embodiment 21

Table 27 Weight percentage and performance parameters of each component in the dye liquid crystal mixture

Example 22

Table 28 Weight percentage and performance parameters of each component in the dye liquid crystal mixture

Embodiment 23

Table 29 Weight percentage and performance parameters of each component in the dye liquid crystal mixture

Embodiment 24

Table 30 Weight percentage and performance parameters of each component in the dye liquid crystal mixture

Embodiment 25

Table 31 Weight percentage and performance parameters of each component in the dye liquid crystal mixture

Embodiment 26

Table 32 Weight percentage and performance parameters of each component in the dye liquid crystal mixture

Embodiment 27

Table 33 Weight percentage and performance parameters of each component in the dye liquid crystal mixture

Embodiment 28

Table 34 Weight percentage and performance parameters of each component in the dye liquid crystal mixture

Embodiment 29

Table 35 Weight percentage and performance parameters of each component in the dye liquid crystal mixture

Embodiment 30

Table 36 Weight percentage and performance parameters of each component in the dye liquid crystal mixture

Embodiment 31

Table 37 Weight percentage and performance parameters of each component in the dye liquid crystal mixture

Implementation 32

Table 38 Weight percentage and performance parameters of each component in the dye liquid crystal mixture

Embodiment 33

Table 39 Weight percentage and performance parameters of each component in the dye liquid crystal mixture

Although the present invention has been described in detail above with general descriptions and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements can be made to the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection claimed by the present invention.

Claims (16)

1. A dichroic dye composition, characterized in that it comprises at least one dichroic dye represented by general formula I, at least one dichroic dye represented by general formula II, at least one dichroic dye represented by general formula III, and at least one dichroic dye represented by general formula IV: The general formula I is specifically: The general formula II is specifically: The general formula III is specifically: The general formula IV is specifically: wherein R ₁ -R ₁₀ each independently represent a straight chain or branched chain alkyl, alkenyl, alkoxy, alkenyloxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy group having 1 to 7 carbon atoms; a ₁ -a ₃ , b ₁ -b ₃ each independently represent 0, 1 or 2; Z ₁ to _{Z 6} each independently represent an ester group, a cyclohexyl group, a phenyl group, an ester phenyl group or a phenylcyclohexyl group. 2. The dichroic dye composition according to claim 1, wherein R ₄ , R ₅ , R ₇ , R ₈ and R ₁₀ represent substituents other than methyl; and/or, a ₁ -a ₃ , b ₁ -b ₃ independently represent 0 or 1; and/or, one or more of Z ₁ , Z ₄ , and Z ₆ represents a phenyl group; More preferably, one or more of R ₄ , R ₅ , R ₇ and R ₈ represent ethyl, and R ₁₀ represents isobutyl or isopentyl. 3. The dichroic dye composition according to claim 1 or 2, characterized in that the general formula I is selected from one or more compounds of formulas I-A-1 to I-B-3: 4. The dichroic dye composition according to any one of claims 1 to 3, characterized in that the general formula Ⅱ is selected from one or more compounds of formulas Ⅱ-A-1 to Ⅱ-B-3: 5. The dichroic dye composition according to any one of claims 1 to 4, characterized in that the general formula III is selected from one or more compounds selected from formulas III-A-1 to III-B-3: 6. The dichroic dye composition according to any one of claims 1 to 5, characterized in that the general formula IV is selected from one or more compounds of formulas IV-1 to IV-6: 7. A dye liquid crystal mixture, characterized in that it comprises the dichroic dye composition according to any one of claims 1 to 6 as a guest, and a liquid crystal composition as a host; preferably, the liquid crystal composition as the host is a nematic liquid crystal composition. 8. The dye liquid crystal mixture according to claim 7, characterized in that the liquid crystal composition comprises at least one of the compounds represented by general formula V and at least one of the compounds represented by general formula VI; Wherein, in the general formula V, R ₁₁ and R ₁₂ each independently represent a C ₁ ～C ₁₂ straight-chain alkyl group, a C ₁ ～C ₁₂ straight-chain alkoxy group or a C ₂ ～C ₁₂ straight-chain alkenyl group; In the general formula VI, R ₁₃ and R ₁₄ each independently represent a C ₁ to C ₁₂ straight-chain alkyl group, a C ₁ to C ₁₂ straight-chain alkoxy group or a C ₂ to C ₁₂ straight-chain alkenyl group; Z ₇ represents -CH ₂ CH ₂ -, -CH=CH-, -CF ₂ O-, -OCF ₂ -, -CH ₂ O-, -OCH ₂ -, -CO-O-, -O-CO-, -C ₂ F ₄ -, -CF=CF-, -CH=CH-CH ₂ O-, or a single bond. 9. The dye liquid crystal mixture according to claim 8, characterized in that the compound represented by general formula V is selected from one or more of formulas VA1 to VA16: Preferably, the compound represented by general formula V is selected from one or more of VA8, VA16, VIB14, and VIB16. 10. The dye liquid crystal mixture according to claim 8 or 9, characterized in that the compound represented by general formula VI is selected from one or more of formulas VIA to VIB: wherein R ₁₃ and R ₁₄ each independently represent a C ₁ to C ₇ straight chain alkyl group, a C ₁ to C ₇ straight chain alkoxy group or a C ₂ to C ₇ straight chain alkenyl group, Preferably, the compound represented by general formula VI is selected from one or more of formula VIA1 to formula VIB16: More preferably, the compound represented by general formula VI is selected from one or more of VIA8, VIA16, VIB6, and VIB14. 11. The dye liquid crystal mixture according to any one of claims 8 to 10, characterized in that the nematic liquid crystal composition comprises one or more compounds represented by general formula VII; wherein R ₁₅ and R ₁₆ each independently represent a C ₁ ～C ₁₂ straight-chain alkyl group, a C ₁ ～C ₁₂ straight-chain alkoxy group or a C ₂ ～C ₁₂ straight-chain alkenyl group, Z ₈ may represent -CH ₂ CH ₂ -, -CH＝CH-, -CF ₂ O-, -OCF ₂ -, -CH ₂ O-, -OCH ₂ -, -CO-O-, -O-CO-, -C ₂ F ₄ -, -CF＝CF-, -CH＝CH-CH ₂ O- or a single bond, A ₁ represents a trans-1,4-cyclohexyl group or a 1,4-phenylene group, and a ₄ is 0 or 1; Preferably, the compound represented by general formula VII is selected from one or more of formula VIIA to formula VIIC: wherein R ₁₅ and R ₁₆ each independently represent a C ₁ ～C ₇ straight-chain alkyl group, a C ₁ ～C ₇ straight-chain alkoxy group or a C ₂ ～C ₇ straight-chain alkenyl group, Z ₈ may represent -CH ₂ CH ₂ -, -CH ₂ O-, -CO-O-, -O-CO-, -CF＝CF-, -CH＝CH-CH ₂ O- or a single bond, A ₁ represents a trans-1,4-cyclohexyl group or a 1,4-phenylene group, and a ₄ is 0 or 1; Further preferably, the compound represented by general formula VII is selected from one or more of formula VIIA1 to formula VIIC16: Most preferably, the compound represented by general formula VII is selected from one or more of VIIA5-VIIA8, VIIA12-VIIA16, VIIB2, VIIB6, VIIB14, VIIC5-VIIC8. 12. The dye liquid crystal mixture according to any one of claims 8 to 11, characterized in that the nematic liquid crystal composition comprises one or more compounds represented by general formula VIII; In the general formula VIII, R ₁₇ and R ₁₈ each independently represent a C ₁ to C ₁₂ straight-chain alkyl group, a C ₁ to C ₁₂ straight-chain alkoxy group or a C ₂ to C ₁₂ straight-chain alkenyl group; A ₂ and A ₃ each independently represent a trans-1,4-cyclohexyl group or a 1,4-phenylene group; Preferably, the compound represented by general formula VIII is selected from one or more of formula VIIIA to formula VIIIB: wherein R ₁₇ and R ₁₈ each independently represent a C ₁ -C ₇ straight-chain alkyl group, a C ₁ -C ₇ straight-chain alkoxy group or a C ₂ -C ₇ straight-chain alkenyl group; More preferably, the compound represented by general formula VIII is selected from one or more of formula VIIIA1 to formula VIIIB24: Most preferably, the compound represented by general formula VIII is selected from one or more of VIIIA7, VIIIA11, VIIIA12, VIIIA21, VIIIB18, and VIIIB22. 13. The dye liquid crystal mixture according to any one of claims 8 to 12, characterized in that the nematic liquid crystal composition comprises the following components in percentage by mass: (1) 22 to 58% of the compound represented by the general formula V; (2) 0 to 22% of a compound represented by Formula VI; (3) 10 to 30% of the compound represented by the general formula VII; (4), 10 to 40% of the compound represented by the general formula VIII; Preferably, the nematic liquid crystal composition comprises the following components in percentage by mass: (1) 25-55% of the compound represented by general formula V; (2) 0 to 20% of a compound represented by Formula VI; (3) 12 to 28% of the compound represented by the general formula VII; (4), 13 to 38% of the compound represented by the general formula VIII; More preferably, the nematic liquid crystal composition comprises the following components in percentage by mass: (1) 25-50% of a compound represented by formula V; (2) 0 to 18% of a compound represented by Formula VI; (3) 15-25% of the compound represented by the general formula VII; (4) 16 to 35% of the compound represented by formula VIII; Further preferably, the nematic liquid crystal composition comprises the following components in percentage by mass: (1) 30-46% of the compound represented by the general formula V; (2) 0 to 15% of a compound represented by Formula VI; (3) 18 to 24% of the compound represented by the general formula VII; (4) 19 to 32% of the compound represented by the general formula VIII. 14. The dye liquid crystal mixture according to any one of claims 7 to 13, characterized in that the dye liquid crystal mixture further comprises a chiral compound, preferably, the chiral compound is R/S811 and/or R/S2011: Further preferably, based on the weight of the liquid crystal composition, the dye liquid crystal mixture contains 0.01 to 2% of the chiral compound, preferably 0.5 to 1.8%, more preferably 0.6 to 1.5%, and most preferably 0.66 to 1.5%. 15. The dye liquid crystal mixture according to claim 14, characterized in that, based on the weight of the liquid crystal composition, the dye liquid crystal mixture comprises the following components in percentage by mass: Preferably, the dye liquid crystal mixture comprises the following components in percentage by mass: Further preferably, the dye liquid crystal mixture comprises the following components in percentage by mass: More preferably, the dye liquid crystal mixture comprises the following components in percentage by mass: 16. The dye liquid crystal mixture according to claim 14, characterized in that, based on the weight of the liquid crystal composition, the dye liquid crystal mixture comprises the following components in percentage by mass: Preferably, the dye liquid crystal mixture comprises the following components in percentage by mass: Further preferably, the dye liquid crystal mixture comprises the following components in percentage by mass: More preferably, the dye liquid crystal mixture comprises the following components in percentage by mass: .