Dimming device

Abstract

The invention provides a dimming device. The dimming device comprises a pair of oppositely arranged transparent conductive base layers and a dimming layer arranged between the transparent conductive base layers, the dimming layer comprises a polymer network formed by at least one polymerizable monomer and a liquid crystal composition dispersed in the polymer network, and the dimming layer further comprises at least one dichroic dye; the dimming device has at least one transparent state for transmitting light incident on the dimming device in an electric field, the haze of the transparent state is smaller than or equal to 2%, the dimming device has at least one shielding state for scattering the light incident on the dimming device in a zero electric field, the haze of the shielding state is larger than or equal to 90%, and the dimming device has a working temperature range not narrower than-20 DEG C to 60 DEG C; the method can be applied to the fields of curtain walls, vehicles and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of liquid crystal dimming devices, and specifically relates to a dimming device, and more specifically to a polymer network stabilized liquid crystal dimming device. Background Art

[0002] As an essential element of modern architecture, glass can make the most of natural light and make the indoor environment comfortable and bright. However, at the same time, it also brings the problem of privacy protection. Traditionally, curtains and blinds are mostly used to solve the problems of light adjustment and privacy protection. However, the installation and cleaning of such mechanical devices are cumbersome and their reliability is poor. Therefore, the intelligent electric control dimming technology has emerged.

[0003] Among the existing industrialized dimming technologies, only PDLC (Polymer Dispersed Liquid Crystal) has the function of privacy protection, but its side viewing angle haze is relatively high, which limits its application. The PSCT (Polymer Stabilized Cholesteric Texture Liquid Crystal) dimming technology can effectively solve the problem of narrow viewing angle of PDLC, with clear full viewing angle and high transmittance. However, the development and application of PSCT are restricted due to problems such as its temperature range and reliability. Especially when applying the PSCT dimming technology to fields such as curtain walls and vehicles, a wide working temperature range and excellent optical performance are necessary conditions for its application.

[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] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a dimming device, and more specifically to provide a polymer network stabilized liquid crystal dimming device. By designing the structure of the dimming device and further designing the specific composition of the dimming layer, the obtained dimming device has a working temperature range not narrower than -20 to 60 °C and can be widely applied to fields such as architecture and vehicles.

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

[0007] In a first aspect, the present invention provides a dimming device, which includes a pair of opposite 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;

[0008] The dimming layer further includes 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. 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.). At this time, the liquid crystal molecules are arranged substantially perpendicular to the transparent conductive substrate layer; it has at least one shielding state in which light incident thereon is scattered under zero electric field. The haze of the shielding state is ≥ 90% (for example, it can be 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97% or 98%, etc.). At this time, the liquid crystal molecules are arranged disorderly;

[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 obtained dimming device has an operating temperature range not narrower than -20 to 60 °C and can be widely applied in fields such as architecture and vehicles.

[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, etc.

[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, etc.

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

[0015] The following are the preferred technical solutions of the present invention, but do not limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the purpose 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 substrate 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 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, PBT film.

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

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

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

[0021] Preferably, the alignment method of the alignment layer is any one of a rubbing alignment method, a photoalignment method, an inclined evaporation method, and an 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 disposed between the transparent conductive substrates of the light modulating device;

[0024] The spacer material has a supporting effect to obtain a uniform light modulating thickness.

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

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

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

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

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

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

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

[0032] The vertical texture of the polymer network is formed by applying a voltage between the upper and lower transparent conductive substrates, so that the liquid crystal molecules are arranged perpendicular to the transparent conductive substrates, and thus the polymerizable monomers are also arranged perpendicular to the transparent conductive substrates, 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 300nm-2500nm, for example, it can be 300nm, 500nm, 700nm, 1000nm, 1200nm, 1500nm, 1800nm, 2000nm, 2200nm, 2400nm or 2500nm.

[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 density of the polymer network is controlled by optimizing the types and contents of polymerizable monomers and initiators; a voltage is applied to arrange the liquid crystal molecules perpendicular to the transparent conductive base layer, and the curing temperature, curing time and curing strength are optimized at the same time, so as to obtain a polymer network that is arranged roughly perpendicular to the transparent base layer and has good reliability; a liquid crystal composition with excellent performance is prepared by designing the specific selection of the liquid crystal composition, 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 the liquid crystal dimming device in the curtain wall and vehicle-mounted fields.

[0037] To achieve this object, the liquid crystal composition of the present invention comprises 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:

[0038]

[0039] Among them, A 1 Represents a single bond, -COO-, -OCO-, -CF 2 O-、-OCF 2 -、-CH 2 O-、-OCH 2 -、-C≡C-、-CH=CH-、-CF 2 CF 2 -, -CF=CF- or -(CH 2 ) a -, wherein a represents an even number from 2 to 10;

[0040] A 2 Represents a single key or

[0041] When A 2 is a single bond, A 3 represents -CH=CH-, -CH=CF-, -CF=CF-, -C≡C- or

[0042] When A 2 is , A 3 represents a single bond, -COO-, -OCO-, -CF 2 O-, -OCF 2 -, -CH 2 O-, -OCH 2 -, or -(CH 2 ) a -, where a represents an even number from 2 to 10.

[0043] Ring H1 to Ring H11 each independently represent

[0044] at least one of, wherein one or at least two H in Ring H1 to Ring H11 can each independently be substituted by any one of a halogen, a C1-C10 straight-chain or branched-chain alkyl, or a C1-C11 ester group;

[0045] R 1 to R 6 each independently represent -CN, -F, -Cl, -NCS, -OCF 3 , -CF 3 , or a C1-C25 straight-chain or branched-chain alkyl, and one or at least two non-adjacent -CH 2 - in the C1-C25 straight-chain or branched-chain alkyl can each independently be substituted by any one of -O-, -S-, -NH-, -N(CH 3 )-, -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-chain or branched-chain alkyl can each independently be substituted by any one of a halogen, -CN, or -CH 3 .

[0046] To achieve the object of the present invention of a large temperature range, the liquid crystal composition needs to have a low eutectic point and a high clearing point at the same time. Among them, the eutectic point of the multi-component system is lower than the melting point of any one of the pure components that make it up. The clearing points of the multi-component system liquid crystal satisfy 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 a liquid crystal monomer, and X i represents the content of the liquid crystal monomer, and T ci represents the clearing point of the liquid crystal monomer.

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

[0050] In summary, to obtain a low eutectic point, liquid crystal compounds with lower melting points must be included to lower the eutectic point of the liquid crystal composition. However, most common liquid crystal compounds have both a low melting point and a low clearing point. Therefore, liquid crystal compounds with a high clearing point must be included to balance the influence of low melting point and low clearing point liquid crystal compounds on the requirement of temperature range. However, liquid crystal compounds with a high clearing point usually have a longer conjugated structure and have a problem of poor solubility. To avoid precipitation and improve stability, it is necessary to limit their content.

[0051] Meanwhile, to achieve the higher scattering state haze of the present invention, the liquid crystal composition must have an appropriate pitch and a large birefringence. When the pitch is large, the scattering effect is poor and the purpose of the present invention cannot be achieved. The birefringence of a liquid crystal compound is dominated by the aromatic component and the π-bond terminal group in the liquid crystal molecule. Generally, the longer the conjugated structure, the larger the birefringence. Liquid crystal compounds with a long conjugated structure are particularly preferred to achieve the purpose of the present invention. By reasonably controlling the content of each compound, the melting point of the liquid crystal composition can be ≤ -30°C and the clearing point can be ≥ 80°C, so as to enable the dimming device to work at a temperature of -20°C - 60°C and the scattering state haze to be ≥ 90%.

[0052] The haze in the transparent state is affected by liquid crystal properties, electric field effects, and the density and arrangement texture of the polymer network. To achieve the purpose of the haze in the transparent state of the dimming device of the present invention being ≤ 2%, it is necessary to control the content of the polymerizable monomer, and also apply a voltage during the curing process to make the liquid crystal molecules align perpendicular to the transparent conductive substrate, and at the same time optimize the curing temperature, curing time, and curing strength to obtain a polymer network with a substantially perpendicular arrangement and 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 may be C1, C2, C5, C7, C10, C13, C15, C18, C20, C22, C24 or C25, etc.

[0057] Halogen includes fluorine atom, chlorine atom, bromine atom and iodine atom.

[0058] As a preferred technical solution of the present invention, the A 1 represents a single bond.

[0059] Preferably, the R 1 represents a straight-chain or branched-chain alkyl group of C2-C10, and one -CH 2 - in the straight-chain or branched-chain alkyl group of C2-C10 (which may be C2, C3, C4, C5, C6, C7, C8, C9 or C10 for example) can be replaced by -O-.

[0060] Preferably, the R 2 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 the general formula I is selected from the group consisting of the following compounds:

[0064]

[0065]

[0066]

[0067] Preferably, the compound represented by the 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, the R 3 represents a straight-chain or branched-chain alkyl group of C2-C5 (which may be C2, C3, C4 or C5 for example).

[0071] Preferably, the R 4 represents any one of -CN, -F, -NCS or a straight-chain or branched-chain alkyl group of C2-C5 (which may be C2, C3, C4 or C5 for example).

[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 the general formula II is selected from the group consisting of the following compounds:

[0076]

[0077]

[0078]

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

[0080]

[0081] As a preferred technical solution of the present invention, the R 5 represents a straight-chain or branched-chain alkyl group having 2 to 5 carbon atoms (for example, it can be C2, C3, C4, or C5).

[0082] Preferably, the R 6 represents any one of -F or a straight-chain or branched-chain alkyl group having 2 to 5 carbon atoms (for example, it can be C2, C3, C4, or C5), and one -CH 2 - in the straight-chain or branched-chain alkyl group having 2 to 5 carbon atoms can be replaced by -O-.

[0083] Preferably, the A 2 represents a single bond, and the A 3 represents -C≡C-, any one of

[0084] Preferably, the A 3 represents The A 3 represents -OCF 2 -.

[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 or a combination of at least two of CB15, R(S)811, R(S)5011, R(S)6N, R(S)2011 or R(S)1011.

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

[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 content of the liquid crystal composition being 100%, the mass percentage content of the compound represented by the 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 content of the liquid crystal composition being 100%, the mass percentage content of the compound represented by the 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 further preferably 32-48%.

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

[0101] Preferably, based on the mass percentage of the liquid crystal composition being 100%, the mass percentage of the chiral compound is 1-20%, 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 being 100%, the mass percentage of the polymerizable monomer is 2-5%, 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 reasonably controlling the contents of each compound, the melting point of the liquid crystal composition can be ≤ -30°C, and the clearing point can be ≥ 80°C, so as to enable the operating temperature of the dimming device to be -20°C - 60°C, and the haze in the scattering state to be ≥ 90%. The haze in the transparent state is affected by the liquid crystal characteristics, the electric field effect, and the density and arrangement texture of the polymer network. To achieve the purpose that the haze in the transparent state of the dimming device of the present invention is ≤ 2%, it is necessary to control the content of the polymerizable monomer, and a voltage that makes the liquid crystal molecules perpendicular to the transparent conductive substrate layer also needs to be applied during the curing process, while optimizing the curing temperature, curing time, and curing strength to obtain a polymer network with a substantially perpendicular arrangement and good reliability.

[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 any one or a combination of at least two of 4,4'-bismaleimidodiphenylmethane, 1,4-bis(maleimidyl)butane, 1,8-bis(maleimidyl)-3,6-dioxaoctane, 1,8-bis(maleimidyl)-3,6-dioxaoctane, 1,11-bis(maleimidyl)-3,6,9-trioxoundecane, 1,6-di(maleimidyl)hexane, bismaleimidomethyl ether, N-cyclohexylmaleimide, N-phenylmaleimide, N-benzylmaleimide, benzoin methyl ether, benzoin dimethyl ether, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, benzophenone, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, and is further preferably any one or a combination of at least two of 4,4'-bismaleimidodiphenylmethane, 1,4-bis(maleimidyl)butane, benzoin methyl ether, and benzoin dimethyl ether.

[0106] 4,4'-bismaleimidodiphenylmethane:

[0107] 1,4-bis(maleimidyl)butane:

[0108] Benzoin methyl ether:

[0109] Benzoin dimethyl ether:

[0110] Preferably, based on the mass percentage of the liquid crystal composition being 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 0.5 μm - 1.2 μm (for example, it can be 0.5 μm, 0.6 μm, 0.7 μm, 0.78 μm, 0.8 μm, 0.88 μm, 0.9 μm, 0.93 μm, 1 μm, 1.1 μm or 1.2 μm, etc.), and more preferably 0.5 μm - 1 μm.

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

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

[0114] (1) By designing the structure of the dimming device and further designing the specific composition of the dimming layer, the obtained dimming device has a working temperature range not narrower than -20 to 60 °C and can be widely applied in fields such as architecture and vehicle-mounted.

[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 working temperature range, high scattering haze and low transmittance haze is prepared, which improves the application value of the liquid crystal dimming device in the curtain wall and vehicle-mounted fields; at the same time, on the premise of solving the problem of narrow PDLC viewing angle (less content of polymerizable materials), it has the characteristics of wide working temperature range and excellent optical properties, improving the practical application value. Specific embodiments

[0116] For the convenience of understanding the present invention, the following examples are listed. Those skilled in the art should understand that the examples are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention.

[0117] Terms and definitions:

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

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

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

[0121] Tni: The clearing point of the liquid crystal composition, measured by DSC TA-20. The measurement conditions are: N2 atmosphere, -50°C (10 min) - 5°C / min - 140°C, hold for 10 min, cool at 5°C / min to -50°C, and the phase transition point is taken as the temperature at which the tangent intersects the baseline;

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

[0123] Driving voltage: The minimum voltage applied to the transparent conductive substrate when the liquid crystal molecules are arranged basically perpendicular to the transparent conductive substrate, obtained by measuring the VT curve with an optoelectronic test device;

[0124] Haze: The ratio of the scattered light flux deviating from the incident light direction through the sample surface to the transmitted light flux. Measured with a WGT-S light transmittance / haze meter at 25°C;

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

[0126] Prepare the liquid crystal composition according to the ratio of each liquid crystal composition in the following examples. The preparation of the liquid crystal composition is carried out according to the conventional methods in the art, such as mixing in a specified ratio by heating, ultrasonic, suspension, etc.

[0127] For the sake of convenience 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 codes of liquid crystal composition

[0129]

[0130]

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

[0132]

[0133] "n = 3", according to the naming principle in Table 1, its corresponding structure is: -C 3 H 7 。

[0134] Example 1

[0135] This example provides a dimming device, whose transparent conductive base layer is ITO glass. Alignment layers are provided on both sides of the liquid crystal adjacent to the transparent conductive base layer. The alignment method is VA alignment, the orientation method is frictionless, the height of the spacer material is 10 μm. The liquid crystal composition of the dimming device in this example includes components with the mass percentage content shown in the following table. The components in the liquid crystal composition provided in this example are mixed to form a mixed liquid crystal, stirred in the dark at 25 °C for 2 h, and formed into a cell by vacuum filling. The process of making and filling the mixed liquid crystal into the cell is strictly carried out in the dark. Then, the device is continuously energized at 60 V in an environment of 25 °C and irradiated under the conditions of a wavelength of 365 nm and an intensity of 7 - 8 mW / cm 2 for 10 min under the condition of irradiation.

[0136]

[0137]

[0138] Example 2

[0139] This example provides a dimming device, whose liquid crystal composition includes components with the mass percentage content shown in the following table. The manufacturing method of the dimming device is the same as that in Example 1.

[0140]

[0141] Example 3

[0142] This example provides a dimming device, whose liquid crystal composition includes components with the mass percentage content shown in the following table. The manufacturing method of the dimming device is the same as that in Example 1.

[0143]

[0144]

[0145] Example 4

[0146] This embodiment provides a dimming device. Its transparent conductive base layer is an ITO PET film sheet. There is no alignment layer provided on the side of the transparent conductive base layer adjacent to the liquid crystal. The height of the spacer material is 10 μm. The liquid crystal composition of the dimming device in this embodiment includes components with mass percentages as shown in the following table. Mix the components in the liquid crystal composition provided in the embodiment to form a mixed liquid crystal, stir it in the dark at 25 °C for 2 h, and form a cell by means of vacuum perfusion. The process of making and perfusion of the mixed liquid crystal is strictly carried out in the dark. Then, continuously apply a voltage of 60 V to the device at 25 °C and irradiate it under the conditions of a wavelength of 365 nm and an intensity of 10 mW / cm 2 for 2 min.

[0147]

[0148] Example 5

[0149] This embodiment provides a dimming device. Its liquid crystal composition includes components with mass percentages as shown in the following table. The manufacturing method of the dimming device is the same as that of Example 4.

[0150]

[0151]

[0152] Example 6

[0153] This embodiment provides a dimming device. Its transparent conductive base layer is ITO glass. There is no alignment layer provided on the side of the transparent conductive base layer adjacent to the liquid crystal. The height of the spacer material is 12 μm. The liquid crystal composition of the dimming device in this embodiment includes components with mass percentages as shown in the following table. Mix the components in the liquid crystal composition provided in the embodiment to form a mixed liquid crystal, stir it in the dark at 25 °C for 2 h, and form a cell by means of vacuum perfusion. The process of making and perfusion of the mixed liquid crystal is strictly carried out in the dark. Then, continuously apply a voltage of 70 V to the device at 25 °C and irradiate it under the conditions of a wavelength of 365 nm and an intensity of 5 mW / cm 2 for 20 min.

[0154]

[0155] Example 7

[0156] This embodiment provides a dimming device. Its transparent conductive base layer is ITO glass. An alignment-free layer is provided on the side of the transparent conductive base layer adjacent to the liquid crystal. The height of the spacer material is 15 μm. The liquid crystal composition of the dimming device in this embodiment includes components with mass percentages as shown in the following table. The components in the liquid crystal composition provided in the embodiment are mixed to form a mixed liquid crystal, which is stirred in the dark for 2 h at 25°C, and the cell is formed by vacuum filling. The process of making and filling the mixed liquid crystal is strictly carried out in the dark. Then, the device is continuously powered at 60 V at 25°C and irradiated at a wavelength of 365 nm and an intensity of 30 mW / cm 2 for 10 min under the condition of irradiation.

[0157]

[0158] Comparative Example 1

[0159] This comparative example provides a dimming device. Its liquid crystal composition includes components with mass percentages as shown in the following table. The manufacturing method of the dimming device is the same as that of Example 1.

[0160]

[0161] Comparative Example 2

[0162] This comparative example provides a dimming device. Its liquid crystal composition includes components with mass percentages as shown in the following table. The manufacturing method of the dimming device is the same as that of Example 1.

[0163]

[0164]

[0165] Comparative Example 3

[0166] This comparative example provides a dimming device. Its liquid crystal composition includes components with mass percentages as shown in the following table. The manufacturing method of the dimming device is the same as that of Example 1.

[0167]

[0168] In the present invention, by specifically selecting the liquid crystal composition and designing the manufacturing process, a dimming device with a wide operating temperature range, high scattering haze, and low haze in the transmission state is prepared, which improves the application value of the liquid crystal dimming device in the curtain wall and vehicle-mounted fields; at the same time, on the premise of solving the problem of narrow viewing angle of PDLC (with a small content of polymerizable materials), it has a wide operating temperature range and excellent optical properties, improving the practical application value.

[0169] The applicant declares that the detailed process flow of the present invention is illustrated by the above embodiments, but the present invention is not limited to the above detailed process flow, that is, it does not mean that the present invention must rely on the above detailed process flow to be implemented. Those skilled in the art should understand that any improvement to the present invention, the equivalent substitution of each raw material of the product of the present invention, the addition of auxiliary components, the selection of specific methods, etc., all fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A dimming device, characterized in that: The dimming device comprises a pair of transparent conductive substrates disposed opposite to each other and a dimming layer disposed between the transparent conductive substrates, wherein the dimming layer comprises 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 that allows light incident thereon to pass under an electric field, and the haze of the transparent state is ≤2%. It has at least one shielding state that allows light incident thereon to scatter under a zero electric field, and the haze of the shielding state is ≥90%. The dimming device has an operating temperature range that is not narrower than -20 to 60°C.

2. The dimming device according to claim 1, characterized in that: The dimming device further comprises an alignment layer disposed on any one side or both sides of the transparent conductive base layer adjacent to the dimming layer; Preferably, the material of the alignment layer is any one of polyimide, polyvinyl alcohol, polyester, epoxy resin, polyurethane, polysilane, polystyrene and derivatives thereof; Preferably, the alignment layer is oriented in any one of a rubbing alignment method, a photo-controlled alignment method, a tilted evaporation method, and a LB film method; Preferably, the alignment type of the alignment layer is any one of VA type, IPS type and TN type.

3. The dimming device according to claim 1, characterized in that: A spacing material is arranged between the transparent conductive base layers; The spacer material has a supporting function; Preferably, the spacer material is selected from at least one of resin, glass fiber and inorganic material; Preferably, the height of the spacer material is 5 μm-50 μm.

4. The dimming device according to claim 1, characterized in that: The polymer network is formed by UV curing or thermal curing of at least one polymerizable monomer; Preferably, the polymer network is arranged perpendicular to the substrate direction; Preferably, the polymerizable monomer is uniformly mixed in the liquid crystal composition before curing.

5. The dimming device according to claim 1, characterized in that: 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; Preferably, the ultraviolet-visible-near-infrared absorption peak of the dichroic dye is 300nm-2500nm.

6. The dimming device according to claim 1, characterized in that: The liquid crystal composition comprises 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 -, wherein 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 following, wherein one or at least two H in rings H1 to H11 may be independently substituted by any one of halogen, C1-C10 straight or branched alkyl, or C1-C11 ester; R1 to R6 each independently represent -CN, -F, -Cl, -NCS, -OCF3, -CF3 or a straight or branched alkyl group of C1-C25, one or at least two non-adjacent -CH2- in the straight or branched alkyl group of C1-C25 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 straight or branched alkyl group of C1-C25 each independently may be replaced by any one of halogen, -CN or -CH3.

7. The dimming device according to claim 6, characterized in that: Said A1 represents a single bond; Preferably, the R1 represents a C2-C10 straight chain or branched alkyl group, and one -CH2- in the C2-C10 straight chain or branched alkyl group may be substituted by -O-; Preferably, R2 represents any one of -CN, -F, -NCS or methyl; Preferably, the ring H1 represents Preferably, the ring H2 represents Preferably, the compound represented by the general formula I is selected from the group consisting of the following compounds: Preferably, the compound represented by the general formula I is selected from the group consisting of the following compounds: Preferably, R3 represents a C2-C5 straight or branched alkyl group; Preferably, R4 represents any one of -CN, -F, -NCS or a C2-C5 straight or branched alkyl group; Preferably, the ring H3 represents Preferably, the ring H4 represents Any of the following: Preferably, the ring H5 represents Any of the following: Preferably, the compound represented by the general formula II is selected from the group consisting of the following compounds: Preferably, the compound represented by the general formula II is selected from the group consisting of the following compounds: Preferably, R5 represents a C2-C5 straight or branched alkyl group; Preferably, the R6 represents any one of -F or a C2-C5 straight chain or branched alkyl group, and one -CH2- in the C2-C5 straight chain or branched alkyl group may be substituted by -O-; Preferably, A2 represents a single bond, A3 represents -C≡C-, Any of the following: Preferably, A3 represents A3 represents -OCF2-; Preferably, the ring H7 represents Preferably, the ring H8 represents Any of the following: Preferably, the loop H9 represents Any of the following: Preferably, the compound represented by the general formula III is selected from the group consisting of the following compounds: Preferably, the compound represented by the general formula III is selected from the group consisting of the following compounds:

8. The dimming device according to claim 6 or 7, characterized in that: The chiral compound is selected from any one or a combination of at least two of CB15, R(S)5011, R(S)6N, R(S)2011 or R(S)1011; Preferably, the polymerizable monomer is selected from any one of RM257, RM82 or LC242, or a combination of at least two thereof.

9. The dimming device according to any one of claims 6 to 8, characterized in that: Taking the mass percentage of the liquid crystal composition as 100%, the mass percentage of the compound represented by the general formula I is 20 to 65%, and more preferably 28 to 61%; Preferably, based on the mass percentage of the liquid crystal composition being 100%, the mass percentage of the compound represented by the general formula II is 30 to 50%, and more preferably 32 to 48%; Preferably, 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 20%, and more preferably 1 to 12%; Preferably, based on the mass percentage of the liquid crystal composition being 100%, the mass percentage of the chiral compound is 1 to 20%; Preferably, based on 100% by mass of the liquid crystal composition, the mass percentage of the polymerizable monomer is 2-5%.

10. The dimming device according to any one of claims 6 to 9, characterized in that: The pitch of the liquid crystal composition is in the range of 0.5 μm to 2 μm, and more preferably in the range of 0.5 μm to 1 μm.

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