A dimming device

Abstract

The present invention provides a dimming device. The dimming device includes a pair of oppositely disposed transparent conductive substrates and a dimming layer disposed between the transparent conductive substrates. The dimming layer includes a polymer network formed by at least one polymerizable monomer and a liquid crystal composition dispersed in the polymer network. The dimming layer also includes at least one dichroic dye. The dimming device has at least one transparent state in an electric field that transmits incident light, with a haze of 2% or less, and at least one shielded state in a zero electric field that scatters incident light, with a haze of 90% or more. The dimming device has an operating temperature range of not less than -20 to 60°C and can be applied to curtain walls, vehicles, and other fields.

Description

Technical Field

[0001] The present invention belongs to the technical field of liquid crystal dimming devices, and in particular relates to a dimming device, and more particularly to a liquid crystal dimming device with a stable polymer network. Background Art

[0002] Glass, as an essential element of modern architecture, can maximize the use of natural light, making the indoor environment comfortable and bright, but at the same time it also brings the problem of privacy protection. Traditionally, curtains and blinds are used to solve the problems of light regulation and privacy protection. However, these mechanical devices are cumbersome to install and clean, and have poor reliability. Therefore, intelligent electric dimming technology came into being.

[0003] Among existing commercial dimming technologies, only PDLC (Polymer Dispersed Liquid Crystal) offers privacy protection, but its high side-view haze limits its application. PSCT (Polymer Stabilized Cholesteric Texture Liquid Crystal) dimming technology effectively addresses the narrow viewing angle issue of PDLC, offering clear, high transmittance at all viewing angles. However, issues such as wide operating temperature range and reliability limit PSCT's development and application. Applications of PSCT dimming technology in areas such as curtain walls and automotive applications require a wide operating temperature range and superior optical performance.

[0004] Therefore, there is an urgent need for a PSCT liquid crystal dimming device with a wide temperature range and excellent optical performance. Summary of the Invention

[0005] To address the shortcomings of the existing technology, the present invention aims to provide a dimming device, more specifically, a liquid crystal dimming device with a stable polymer network. By designing the dimming device structure and further designing the specific composition of the dimming layer, the present invention achieves a dimming device with an operating temperature range of no less than -20°C to 60°C, making it suitable for a wide range of applications in architecture, automotive, and other fields.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a dimming device, comprising a pair of opposing transparent conductive substrates and a dimming layer disposed between the transparent conductive substrates, wherein the dimming layer comprises a polymer network formed from at least one polymerizable monomer and a liquid crystal composition dispersed in the polymer network;

[0008] The dimming layer further comprises at least one dichroic dye,

[0009] The dimming device has at least one transparent state in which light incident thereon is transmitted under an electric field, and the haze of the transparent state is ≤2% (for example, it can be 0.2%, 0.4%, 0.6%, 0.8%, 1%, 1.2%, 1.4%, 1.6%, 1.8% or 2%, etc.), in which case the liquid crystal molecules are arranged substantially perpendicular to the transparent conductive substrate; and has at least one shielding state in which light incident thereon is scattered under a zero electric field, and the haze of the shielding state is ≥90% (for example, it can be 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97% or 98%, etc.), in which case the liquid crystal molecules are arranged in a disordered manner;

[0010] The dimming device has an operating temperature range not narrower than -20 to 60°C.

[0011] By designing the structure of the dimming device and further designing the specific composition of the dimming layer, the dimming device obtained in the present invention has an operating temperature range not narrower than -20 to 60°C and can be widely used in the fields of construction, vehicle and the like.

[0012] The lower limit of the operating temperature of the dimming device is ≤-20°C, for example, it can be -40°C, -38°C, -36°C, -34°C, -32°C, -30°C, -28°C, -26°C, -24°C, -22°C or -20°C.

[0013] The upper limit of the operating temperature of the dimming device is ≥60°C, for example, it can be 60°C, 62°C, 64°C, 66°C, 68°C, 70°C, 72°C, 74°C, 76°C, 78°C or 80°C.

[0014] The transmission state driving voltage of the dimming device is ≤100V, for example, it can be 45V, 48V, 50V, 55V, 60V, 65V, 70V, 75V, 80V, 85V, 90V, 95V or 100V.

[0015] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the objectives and beneficial effects of the present invention can be better achieved and realized.

[0016] As a preferred technical solution of the present invention, the transparent conductive base layer of the dimming device is any one of flat glass, tempered glass, semi-tempered glass, float glass or plastic substrate film with a conductive layer provided on one side or both sides.

[0017] Preferably, the plastic substrate film is selected from at least one of PET film, PI film, PTFE film, PP film, PC film, PVC film, PE film, PS film, PA film, PEN film, PMMA film and PBT film.

[0018] Preferably, the material of the conductive layer is any one of a metal oxide film, a metal nanowire conductive film, a metal grid, and a carbon-based conductive film.

[0019] As a preferred technical solution of the present invention, the dimming device further includes an alignment layer disposed on any one side or both sides of the transparent conductive base layer adjacent to the dimming layer.

[0020] Preferably, the material of the alignment layer is any one of polyimide, polyvinyl alcohol, polyester, epoxy resin, polyurethane, polysilane, polystyrene and derivatives thereof.

[0021] Preferably, the alignment layer is aligned in any one of a rubbing alignment method, a photo-controlled alignment method, a tilted evaporation method, and a LB film method.

[0022] Preferably, the alignment type of the alignment layer is any one of VA type, IPS type and TN type.

[0023] As a preferred technical solution of the present invention, a spacer material is provided between the transparent conductive substrates of the dimming device;

[0024] The spacer material has a supporting function to obtain a uniform dimming thickness.

[0025] Preferably, the spacer material is selected from at least one of resin, glass fiber and inorganic material.

[0026] Preferably, the shape of the spacer material may be spherical, rod-like or a mixed shape.

[0027] Preferably, the height of the spacer material is 5 μm-50 μm, for example, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm or 50 μm.

[0028] As a preferred technical solution of the present invention, the polymer network of the dimming device is formed by UV curing or thermal curing of at least one polymerizable monomer.

[0029] Preferably, the polymer network of the dimming device is formed by UV curing of at least one polymerizable monomer.

[0030] Preferably, the polymer network is arranged perpendicular to the substrate.

[0031] Preferably, the polymerizable monomer is uniformly mixed in the liquid crystal composition before curing.

[0032] The vertical texture of the polymer network is achieved by applying voltage to the upper and lower transparent conductive substrates, so that the liquid crystal molecules are arranged perpendicular to the transparent conductive substrate, so that the polymerizable monomers are also arranged perpendicular to the transparent conductive substrate, and the curing reaction is carried out under this texture.

[0033] As a preferred technical solution of the present invention, the dichroic dye is selected from any one of azo dyes, anthraquinone dyes, benzothiadiazole dyes or rylene dyes, or a combination of at least two thereof.

[0034] Preferably, the UV-visible-near-infrared absorption peak of the dichroic dye is 300 nm-2500 nm, for example, it can be 300 nm, 500 nm, 700 nm, 1000 nm, 1200 nm, 1500 nm, 1800 nm, 2000 nm, 2200 nm, 2400 nm or 2500 nm.

[0035] The dichroic dye is uniformly mixed in the liquid crystal composition.

[0036] The photoelectric properties, operating temperature, and reliability of the dimming layer of the dimming device are affected by the liquid crystal composition and the polymer network characteristics. The present invention controls the density of the polymer network by optimizing the types and contents of polymerizable monomers and initiators; by applying a voltage that aligns the liquid crystal molecules perpendicularly to the transparent conductive base layer, and simultaneously optimizing the curing temperature, curing time, and curing strength, a polymer network that is arranged roughly perpendicular to the transparent base layer and has good reliability is obtained; by designing the specific selection of the liquid crystal composition, a liquid crystal composition with excellent performance is prepared, and then a dimming device with a wide operating temperature range, high scattering haze, low transmitted haze, and good reliability is prepared, thereby improving the application value of liquid crystal dimming devices in curtain walls and automotive fields.

[0037] To achieve this object, the liquid crystal composition of the present invention comprises at least one compound represented by formula I, at least one compound represented by formula II, at least one compound represented by formula III, at least one chiral compound, and at least one polymerizable monomer:

[0038]

[0039] Wherein, A1 represents a single bond, -COO-, -OCO-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -C≡C-, -CH=CH-, -CF2CF2-, -CF=CF- or -(CH2) a -, where a represents an even number from 2 to 10;

[0040] A2 represents a single bond or

[0041] When A2 is a single bond, A3 represents -CH=CH-, -CH=CF-, -CF=CF-, -C≡C- or

[0042] When A2 is When A3 represents a single bond, -COO-, -OCO-, -CF2O-, -OCF2-, -CH2O-, -OCH2- or -(CH2) a -, where a represents an even number from 2 to 10.

[0043] Rings H1 to H11 each independently represent

[0044] At least one of the rings H1 to H11, wherein one or at least two H groups of the rings H1 to H11 may be independently substituted by any one of halogen, C1-C10 linear or branched alkyl, or C1-C11 ester group;

[0045] R1 to R6 each independently represent -CN, -F, -Cl, -NCS, -OCF3, -CF3 or a C1-C25 straight or branched alkyl group, one or at least two non-adjacent -CH2- in the C1-C25 straight or branched alkyl group each independently can be replaced by any one of -O-, -S-, -NH-, -N(CH3)-, -CO-, -COO-, -OCO-, -OCOO-, -SCO-, -COS-, -CH=CH-, -CH=CF-, -CF=CF- or -C≡C-; one or at least two H in the C1-C25 straight or branched alkyl group each independently can be replaced by any one of halogen, -CN or -CH3.

[0046] To achieve the wide temperature range of the present invention, the liquid crystal composition must have both a low eutectic point and a high clearing point. The eutectic point of the multi-component system is lower than the melting point of any of its pure components. The clearing point of the liquid crystal of the multi-component system satisfies the following relationship:

[0047]

[0048] Among them, T C represents the clearing point of the mixed liquid crystal, N represents the total number of liquid crystal monomers, A represents the liquid crystal monomer, X i Indicates the content of liquid crystal monomers, T ci Indicates the clearing point of a liquid crystal monomer.

[0049] Ideally, when liquid crystal compounds of the same polarity are mixed, the above formula holds true. However, when polar compounds and non-polar compounds are mixed, a large negative deviation generally occurs.

[0050] In summary, to achieve a low eutectic point, a liquid crystal compound with a relatively low melting point must be included to lower the eutectic point of the liquid crystal composition. However, typical liquid crystal compounds often exhibit low melting points and low clearing points. Therefore, liquid crystal compounds with high clearing points must be included to balance the impact of these low melting points and low clearing points on the required temperature bandwidth. However, liquid crystal compounds with high clearing points typically have long conjugated structures, resulting in poor solubility. To avoid precipitation and improve stability, their content must be limited.

[0051] Furthermore, to achieve the high scattering haze of the present invention, the liquid crystal composition must possess an appropriate helical pitch and high birefringence. A large helical pitch results in poor scattering, failing to achieve the present invention's objectives. The birefringence of liquid crystal compounds is governed by the aromatic components and π-bond end groups within the liquid crystal molecules. Generally, longer conjugated structures increase birefringence. Liquid crystal compounds with long conjugated structures are particularly preferred for achieving the present invention's objectives. By rationally controlling the content of each compound, the liquid crystal composition can achieve a melting point of ≤-30°C and a clearing point of ≥80°C, enabling the dimming device to operate at a temperature between -20°C and 60°C, with a scattering haze of ≥90%.

[0052] The haze in the transparent state is affected by the liquid crystal properties, the effect of the electric field, and the density and arrangement texture of the polymer network. In order to achieve the purpose of the transparent state haze of the dimming device of the present invention being ≤2%, it is necessary to control the content of the polymerizable monomer and apply a voltage during the curing process to align the liquid crystal molecules perpendicular to the transparent conductive base layer. At the same time, the curing temperature, curing time, and curing strength are optimized to obtain a polymer network that is roughly vertically aligned and has good reliability.

[0053] In the present invention, a represents 2, 4, 6, 8 or 10.

[0054] C1-C10 can be C1, C2, C3, C4, C5, C6, C7, C8, C9 or C10.

[0055] C1-C10 can be C1, C2, C3, C4, C5, C6, C7, C8, C9, C10 or C11.

[0056] C1-C25 can be C1, C2, C5, C7, C10, C13, C15, C18, C20, C22, C24 or C25, etc.

[0057] The halogen includes a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0058] As a preferred technical solution of the present invention, A1 represents a single bond.

[0059] Preferably, R1 represents a C2-C10 straight chain or branched alkyl group, and one -CH2- in the C2-C10 (for example, C2, C3, C4, C5, C6, C7, C8, C9 or C10) straight chain or branched alkyl group may be replaced by -O-.

[0060] Preferably, R2 represents any one of -CN, -F, -NCS or methyl.

[0061] Preferably, the ring H1 represents

[0062] Preferably, the ring H2 represents

[0063] Preferably, the compound represented by general formula I is selected from the group consisting of the following compounds:

[0064]

[0065]

[0066]

[0067] Preferably, the compound represented by general formula I is selected from the group consisting of the following compounds:

[0068]

[0069]

[0070] As a preferred technical solution of the present invention, R3 represents a C2-C5 (eg, C2, C3, C4 or C5) straight-chain or branched alkyl group.

[0071] Preferably, R4 represents any one of -CN, -F, -NCS or a C2-C5 (eg, C2, C3, C4 or C5) linear or branched alkyl group.

[0072] Preferably, the ring H3 represents

[0073] Preferably, the ring H4 represents Any one of .

[0074] Preferably, the ring H5 represents Any one of .

[0075] Preferably, the compound represented by general formula II is selected from the group consisting of the following compounds:

[0076]

[0077]

[0078]

[0079] Preferably, the compound represented by general formula II is selected from the group consisting of the following compounds:

[0080]

[0081] As a preferred technical solution of the present invention, R5 represents a C2-C5 (for example, C2, C3, C4 or C5) straight-chain or branched alkyl group.

[0082] Preferably, the R6 represents -F or any one of a C2-C5 (e.g., C2, C3, C4, or C5) linear or branched alkyl group, and one -CH2- in the C2-C5 linear or branched alkyl group may be substituted by -O-.

[0083] Preferably, A2 represents a single bond, A3 represents -C≡C-, Any one of .

[0084] Preferably, said A3 represents The A3 represents -OCF2-.

[0085] Preferably, the ring H7 represents

[0086] Preferably, the ring H8 represents Any one of .

[0087] Preferably, the ring H9 represents Any one of .

[0088] Preferably, the compound represented by the general formula III is selected from the group consisting of the following compounds:

[0089]

[0090]

[0091] Preferably, the compound represented by the general formula III is selected from the group consisting of the following compounds:

[0092]

[0093] As a preferred technical solution of the present invention, the chiral compound is selected from any one of CB15, R(S)811, R(S)5011, R(S)6N, R(S)2011 or R(S)1011, or a combination of at least two thereof.

[0094] Preferably, the polymerizable monomer is selected from any one of RM257, RM82 or LC242, or a combination of at least two thereof.

[0095] In the present invention, RM257:

[0096] RM82:

[0097] LC242:

[0098] As a preferred technical solution of the present invention, based on the mass percentage of the liquid crystal composition as 100%, the mass percentage of the compound represented by general formula I is 20-65%, for example, it can be 20%, 25%, 28%, 30%, 35%, 40%, 45%, 50%, 55%, 61% or 65%, etc., and is further preferably 28-61%.

[0099] Preferably, based on the mass percentage of the liquid crystal composition as 100%, the mass percentage of the compound represented by general formula II is 30-50%, for example, it can be 30%, 32%, 34%, 36%, 38%, 40%, 42%, 44%, 46%, 48% or 50%, etc., and is more preferably 32-48%.

[0100] Preferably, based on the mass percentage of the liquid crystal composition as 100%, the mass percentage of the compound represented by general formula III is 1 to 20%, for example, it can be 1%, 2%, 4%, 6%, 8%, 10%, 12%, 14%, 16%, 18% or 20%, etc., and more preferably 1 to 12%.

[0101] Preferably, based on the mass percentage of the liquid crystal composition as 100%, the mass percentage of the chiral compound is 1 to 20%, for example, it can be 1%, 2%, 4%, 6%, 8%, 10%, 12%, 14%, 16%, 18% or 20%, etc.

[0102] Preferably, based on the mass percentage of the liquid crystal composition as 100%, the mass percentage of the polymerizable monomer is 2 to 5%, for example, it can be 2%, 2.2%, 2.5%, 2.7%, 3%, 3.3%, 3.6%, 3.8%, 4%, 4.2%, 4.6% or 5%, etc.

[0103] By properly controlling the content of each compound, the liquid crystal composition can achieve a melting point of ≤-30°C and a clearing point of ≥80°C, enabling the dimming device to operate at a temperature between -20°C and 60°C and a haze in the scattered state of ≥90%. The haze in the transparent state is influenced by the liquid crystal properties, the electric field, and the density and alignment of the polymer network. To achieve a haze of ≤2% in the transparent state of the dimming device of the present invention, it is necessary to control the content of the polymerizable monomers and apply a voltage during the curing process that aligns the liquid crystal molecules perpendicular to the transparent conductive substrate. Furthermore, the curing temperature, curing time, and curing strength are optimized to achieve a polymer network that is substantially vertically aligned and highly reliable.

[0104] As a preferred technical solution of the present invention, the liquid crystal composition further includes a photoinitiator.

[0105] Preferably, the photoinitiator is selected from 4,4'-bismaleimidodiphenylmethane, 1,4-bis(maleimido)butane, 1,8-bis(maleimido)-3,6-dioxaoctane, 1,8-bis(maleimido)-3,6-dioxaoctane, 1,11-bismaleimido-3,6,9-trioxoundecane, 1,6-bis(maleimido)hexane, bismaleimidomethyl ether, N-cyclohexylmaleimide, N-phenylmaleimide, Any one or a combination of at least two of imide, N-benzylmaleimide, benzoin methyl ether, benzoin dimethyl ether, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, benzophenone, phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide, and more preferably any one or a combination of at least two of 4,4'-bismaleimidodiphenylmethane, 1,4-bis(maleimido)butane, benzoin methyl ether, and benzoin dimethyl ether.

[0106] 4,4'-Bismaleimidodiphenylmethane:

[0107] 1,4-Bis(maleimido)butane:

[0108] Benzoin methyl ether:

[0109] Benzoin dimethyl ether:

[0110] Preferably, based on the mass percentage of the liquid crystal composition as 100%, the mass percentage of the photoinitiator is 0.1-1%, for example, it can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9% or 1%, etc.

[0111] As a preferred technical solution of the present invention, the pitch range of the liquid crystal composition is 0.5μm to 1.2μm (for example, it can be 0.5μm, 0.6μm, 0.7μm, 0.78μm, 0.8μm, 0.88μm, 0.9μm, 0.93μm, 1μm, 1.1μm or 1.2μm, etc.), and is further preferably 0.5μm to 1μm.

[0112] As a preferred technical solution of the present invention, the thickness of the liquid crystal layer is 1μm to 60μm (for example, it can be 1μm, 5μm, 10μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, 55μm or 60μm, etc.), and is further preferably 5μm to 30μm.

[0113] Compared with the prior art, the present invention has the following beneficial effects:

[0114] (1) The present invention designs the structure of the dimming device and further designs the specific composition of the dimming layer. The resulting dimming device has an operating temperature range of not narrower than -20 to 60°C and can be widely used in fields such as construction and vehicles.

[0115] (2) In the present invention, by designing the specific selection of the liquid crystal composition, a liquid crystal composition with excellent performance is prepared, and then a dimming device with a wide operating temperature range, high scattering haze, and low transmission haze is prepared, thereby improving the application value of the liquid crystal dimming device in the curtain wall and vehicle fields; at the same time, while solving the problem of the narrow viewing angle of PDLC (low content of polymerizable materials), it has the characteristics of a wide operating temperature range and excellent optical properties, thereby improving the practical application value. DETAILED DESCRIPTION

[0116] For the convenience of understanding the present invention, the present invention is given below with examples. It should be understood by those skilled in the art that the examples are only for the purpose of helping to understand the present invention and should not be regarded as specific limitations of the present invention.

[0117] Terms and Definitions:

[0118] Polymerizable monomer: refers to a liquid crystal material with a relatively low molecular weight. The liquid crystal material generally has a liquid crystal core with one or more reactive functional groups at the end. It can be polymerized, cross-linked or cured to form a polymer network through ultraviolet light irradiation or thermal curing.

[0119] Polymer network: refers to a polymer network formed by cross-linking and curing of polymerizable monomers.

[0120] Pitch: Pitch = 1 / (c*HTP), where c is the chiral compound content and HTP is the helical twisting power constant of the chiral compound.

[0121] Tni: clearing point of the liquid crystal composition, measured by DSC TA-20 under the following conditions: N2 atmosphere, -50°C (10 min) to 140°C at 5°C / min, dwell time of 10 min, then cooling at 5°C / min to -50°C. The phase transition point is the temperature at which the tangent line intersects the baseline.

[0122] Tsn: eutectic point of liquid crystal composition, measured in the same way as Tni;

[0123] Driving voltage: The minimum voltage applied to the transparent conductive substrate required to make the liquid crystal molecules align substantially perpendicular to the transparent conductive substrate, obtained by measuring the VT curve using photoelectric testing equipment;

[0124] Haze: The ratio of the scattered light flux that deviates from the direction of the incident light through the sample surface to the transmitted light flux. Measured using a WGT-S Transmittance / Haze Tester at 25°C.

[0125] The compounds used in the following examples can be synthesized by known methods or obtained through commercial channels. These synthesis techniques are conventional, and the resulting liquid crystal compositions have been tested to meet the standards of electronic compounds.

[0126] Liquid crystal compositions were prepared according to the ratios of the liquid crystal compositions in the following examples. The preparation of the liquid crystal compositions was carried out according to conventional methods in the art, such as mixing in a prescribed ratio by heating, ultrasonication, suspension, etc.

[0127] For ease of expression, in the following examples, the group structures of the components in the liquid crystal composition are represented by the codes listed in Table 1:

[0128] Table 1 Group structure code of liquid crystal composition

[0129]

[0130]

[0131] For example, "5PPN", according to the naming principle in Table 1, its corresponding structure is:

[0132]

[0133] "n=3", according to the naming principle of Table 1, its corresponding structure is: -C3H7.

[0134] Example 1

[0135] The present embodiment provides a dimming device, wherein the transparent conductive substrate is ITO glass, and alignment layers are provided on both sides of the transparent conductive substrate adjacent to the liquid crystal, the alignment mode is VA alignment, the orientation mode is frictionless, and the height of the spacer material is 10 μm. The liquid crystal composition of the dimming device of the present embodiment includes the components in the mass percentage as shown in the following table. The components in the liquid crystal composition provided in the present embodiment are mixed to form a mixed liquid crystal, stirred in the dark at 25°C for 2 hours, and formed into a box by vacuum perfusion. The mixed liquid crystal is strictly protected from light during the process of forming and perfusing the box. Then, the device is continuously energized at 60V at 25°C and placed in a 365nm wavelength and an intensity of 7-8mW / cm 2 Condition irradiation 10min.

[0136]

[0137]

[0138] Example 2

[0139] This embodiment provides a dimming device, the liquid crystal composition of which includes components in the mass percentages shown in the following table. The dimming device is manufactured in the same manner as in Example 1.

[0140]

[0141] Example 3

[0142] This embodiment provides a dimming device, the liquid crystal composition of which includes components in the mass percentages shown in the following table. The dimming device is manufactured in the same manner as in Example 1.

[0143]

[0144]

[0145] Example 4

[0146] The present embodiment provides a dimming device, wherein the transparent conductive base layer is an ITO PET film sheet, a non-aligned layer is provided adjacent to the liquid crystal side of the transparent conductive base layer, and the height of the spacer material is 10 μm. The liquid crystal composition of the dimming device of the present embodiment includes the components in the mass percentages shown in the following table. The components in the liquid crystal composition provided in the embodiment are mixed to form a mixed liquid crystal, stirred in the dark at 25°C for 2 hours, and formed into a box by vacuum perfusion. The mixed liquid crystal is strictly protected from light during the process of forming and perfusing the box. Then, the device is continuously energized at 60V at 25°C and placed in a 365nm wavelength and an intensity of 10mW / cm 2 Condition irradiation 2min.

[0147]

[0148] Example 5

[0149] This embodiment provides a dimming device, the liquid crystal composition of which includes components in the mass percentages shown in the following table. The dimming device is manufactured in the same manner as in Example 4.

[0150]

[0151]

[0152] Example 6

[0153] The present embodiment provides a dimming device, wherein the transparent conductive substrate is ITO glass, a non-aligned layer is provided adjacent to the liquid crystal side of the transparent conductive substrate, and the height of the spacer material is 12 μm. The liquid crystal composition of the dimming device of the present embodiment includes the components in the mass percentages shown in the following table. The components in the liquid crystal composition provided in the embodiment are mixed to form a mixed liquid crystal, stirred in the dark at 25°C for 2 hours, and formed into a box by vacuum perfusion. The mixed liquid crystal is strictly protected from light during the preparation and perfusion process. Then, the device is continuously energized at 70V at 25°C and exposed to a light source with a wavelength of 365nm and an intensity of 5mW / cm 2 Condition irradiation for 20 minutes.

[0154]

[0155] Example 7

[0156] The present embodiment provides a dimming device, wherein the transparent conductive substrate is ITO glass, a non-aligned layer is provided adjacent to the liquid crystal side of the transparent conductive substrate, and the height of the spacer material is 15 μm. The liquid crystal composition of the dimming device of the present embodiment includes the components in the mass percentages shown in the following table. The components in the liquid crystal composition provided in the embodiment are mixed to form a mixed liquid crystal, stirred in the dark at 25°C for 2 hours, and formed into a box by vacuum perfusion. The mixed liquid crystal is strictly protected from light during the preparation and perfusion process. Then, the device is continuously energized at 60V at 25°C and placed in a 365nm wavelength and 30mW / cm 2 Condition irradiation 10min.

[0157]

[0158] Comparative Example 1

[0159] This comparative example provides a dimming device, the liquid crystal composition of which includes components in the mass percentages shown in the following table. The dimming device is manufactured in the same manner as in Example 1.

[0160]

[0161] Comparative Example 2

[0162] This comparative example provides a dimming device, the liquid crystal composition of which includes components in the mass percentages shown in the following table. The dimming device is manufactured in the same manner as in Example 1.

[0163]

[0164]

[0165] Comparative Example 3

[0166] This comparative example provides a dimming device, the liquid crystal composition of which includes components in the mass percentages shown in the following table. The dimming device is manufactured in the same manner as in Example 1.

[0167]

[0168] In the present invention, by specifically selecting a liquid crystal composition and designing a manufacturing process, a dimming device with a wide operating temperature range, high scattering haze, and low transmitted haze is prepared, thereby improving the application value of liquid crystal dimming devices in curtain walls and automotive fields; at the same time, while solving the problem of narrow viewing angle of PDLC (low content of polymerizable materials), the device has a wide operating temperature range and excellent optical properties, thereby improving its practical application value.

[0169] The applicant declares that the present invention uses the above-described embodiments to illustrate the detailed process flow of the present invention, but the present invention is not limited to the above-described detailed process flow, that is, it does not mean that the present invention must rely on the above-described detailed process flow to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent replacements for various raw materials in the products of the present invention, addition of auxiliary ingredients, and selection of specific methods, etc., are all within the scope of protection and disclosure of the present invention.

Claims

1. A dimming device, characterized in that: The dimming device includes a pair of oppositely disposed transparent conductive substrates and a dimming layer disposed between the transparent conductive substrates, wherein the dimming layer includes a polymer network formed by at least one polymerizable monomer and a liquid crystal composition dispersed in the polymer network; The dimming layer further comprises at least one dichroic dye; The dimming device has at least one transparent state in which light incident thereon is transmitted under an electric field, and the haze of the transparent state is ≤2%, and at least one shielding state in which light incident thereon is scattered under a zero electric field, and the haze of the shielding state is ≥90%. The dimming device has an operating temperature range not narrower than -20 to 60°C; The liquid crystal composition includes at least one compound represented by general formula I, at least one compound represented by general formula II, at least one compound represented by general formula III, at least one chiral compound, and at least one polymerizable monomer: Wherein, A1 represents a single bond, -COO-, -OCO-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -C≡C-, -CH=CH-, -CF2CF2-, -CF=CF- or -(CH2) a -, where a represents an even number from 2 to 10; A2 represents a single bond or When A2 is a single bond, A3 represents -CH=CH-, -CH=CF-, -CF=CF-, -C≡C- or When A2 is When A3 represents a single bond, -COO-, -OCO-, -CF2O-, -OCF2-, -CH2O-, -OCH2- or -(CH2) a -, where a represents an even number from 2 to 10; Rings H1 to H11 each independently represent At least one of the rings H1 to H11, wherein one or at least two H groups of the rings H1 to H11 may be independently substituted by any one of halogen, C1-C10 linear or branched alkyl, or C1-C11 ester group; R1 to R6 each independently represent -CN, -F, -Cl, -NCS, -OCF3, -CF3 or a C1-C25 straight or branched alkyl group, one or at least two non-adjacent -CH2- in the C1-C25 straight or branched alkyl group each independently may be replaced by any one of -O-, -S-, -NH-, -N(CH3)-, -CO-, -COO-, -OCO-, -OCOO-, -SCO-, -COS-, -CH=CH-, -CH=CF-, -CF=CF- or -C≡C-; one or at least two H in the C1-C25 straight or branched alkyl group each independently may be replaced by any one of halogen, -CN or -CH3; Based on the mass percentage of the liquid crystal composition as 100%, the mass percentage of the compound represented by general formula I is 20-65%, the mass percentage of the compound represented by general formula II is 30-50%, the mass percentage of the compound represented by general formula III is 1-20%, the mass percentage of the chiral compound is 1-20%, and the mass percentage of the polymerizable monomer is 2-5%; The liquid crystal composition has a helical pitch ranging from 0.5 μm to 2 μm.

2. The dimming device according to claim 1, wherein: The dimming device further includes an alignment layer disposed on the transparent conductive base layer adjacent to any one side or both sides of the dimming layer.

3. The dimming device according to claim 2, wherein: The material of the alignment layer is any one of polyimide, polyvinyl alcohol, polyester, epoxy resin, polyurethane, polysilane, polystyrene and derivatives thereof.

4. The dimming device according to claim 2, wherein: The alignment layer is aligned in any one of a rubbing alignment method, a light-controlled alignment method, an oblique evaporation method, and an LB film method.

5. The dimming device according to claim 2, wherein: The alignment type of the alignment layer is any one of VA type, IPS type and TN type.

6. The dimming device according to claim 1, wherein: A spacer material is provided between the transparent conductive base layers; The spacer material has a supporting function.

7. The dimming device according to claim 6, wherein: The spacer material is selected from at least one of resin, glass fiber and inorganic material.

8. The dimming device according to claim 6, wherein: The height of the spacer material is 5 μm-50 μm.

9. The dimming device according to claim 1, wherein: The polymer network is formed by UV curing or thermal curing of at least one polymerizable monomer.

10. The dimming device according to claim 1, wherein: The polymer network is aligned perpendicular to the substrate.

11. The dimming device according to claim 1, wherein: The polymerizable monomer is uniformly mixed in the liquid crystal composition before curing.

12. The dimming device according to claim 1, wherein: The dichroic dye is selected from any one of azo dyes, anthraquinone dyes, benzothiadiazole dyes or rylene dyes, or a combination of at least two thereof.

13. The dimming device according to claim 1, wherein: The ultraviolet-visible-near-infrared absorption peak of the dichroic dye is 300nm-2500nm.

14. The dimming device according to claim 1, wherein: The A1 represents a single bond.

15. The dimming device according to claim 1, wherein: Said R1 represents a C2-C10 straight chain or branched alkyl group, and one -CH2- in said C2-C10 straight chain or branched alkyl group may be substituted by -O-.

16. The dimming device according to claim 1, wherein: The R2 represents any one of -CN, -F, -NCS or methyl.

17. The dimming device according to claim 1, wherein: The loop H1 represents 18. The dimming device according to claim 1, wherein: The ring H2 represents 19. The dimming device according to claim 1, wherein: The compound represented by the general formula I is selected from the group consisting of the following compounds:

20. The dimming device according to claim 19, wherein: The compound represented by the general formula I is selected from the group consisting of the following compounds:

21. The dimming device according to claim 1, wherein: The R3 represents a C2-C5 straight-chain or branched alkyl group.

22. The dimming device according to claim 1, wherein: The R4 represents any one of -CN, -F, -NCS or a C2-C5 straight or branched alkyl group.

23. The dimming device according to claim 1, wherein: The loop H3 represents 24. The dimming device according to claim 1, wherein: The loop H4 represents Any one of .

25. The dimming device according to claim 1, wherein: The loop H5 represents Any one of .

26. The dimming device according to claim 1, wherein: The compound represented by the general formula II is selected from the group consisting of the following compounds:

27. The dimming device according to claim 26, wherein: The compound represented by the general formula II is selected from the group consisting of the following compounds:

28. The dimming device according to claim 1, wherein: The R5 represents a C2-C5 straight-chain or branched alkyl group.

29. The dimming device according to claim 1, wherein: Said R6 represents any one of -F or C2-C5 straight chain or branched alkyl, and one -CH2- in said C2-C5 straight chain or branched alkyl may be substituted by -O-.

30. The dimming device according to claim 1, wherein: A2 represents a single bond, A3 represents -C≡C-, Any one of .

31. The dimming device according to claim 1, wherein: The A2 represents The A3 represents -OCF2-.

32. The dimming device according to claim 1, wherein: The loop H7 represents 33. The dimming device according to claim 1, wherein: The loop H8 represents Any one of .

34. The dimming device according to claim 1, wherein: The loop H9 represents Any one of .

35. The dimming device according to claim 1, wherein: The compound represented by the general formula III is selected from the group consisting of the following compounds:

36. The dimming device according to claim 35, wherein: The compound represented by the general formula III is selected from the group consisting of the following compounds:

37. The dimming device according to claim 1, characterized in that: The chiral compound is selected from any one of CB15, R(S)5011, R(S)6N, R(S)2011 or R(S)1011, or a combination of at least two thereof.

38. The dimming device according to claim 1, wherein: The polymerizable monomer is selected from any one of RM257, RM82, and LC242, or a combination of at least two thereof.

39. The dimming device according to claim 1, characterized in that Taking the mass percentage of the liquid crystal composition as 100%, the mass percentage of the compound represented by general formula I is 28-61%.

40. The dimming device according to claim 1, wherein: Taking the mass percentage of the liquid crystal composition as 100%, the mass percentage of the compound represented by general formula II is 32-48%.

41. The dimming device according to claim 1, wherein: Based on the mass percentage of the liquid crystal composition being 100%, the mass percentage of the compound represented by the general formula III is 1 to 12%.

42. The dimming device according to claim 1, characterized in that The liquid crystal composition has a helical pitch ranging from 0.5 μm to 1 μm.

Images