A yellowing-resistant low-voltage driven liquid crystal dimming film

Abstract

The application provides a yellowing-resistant low-voltage driven liquid crystal dimming film, which contains a liquid crystal dimming layer, the liquid crystal dimming layer contains nematic liquid crystal, polymer and ionic liquid crystal, the mass of the polymer is 30% to 70% of the total mass of the polymer and the nematic liquid crystal, and the weight percentage of the ionic liquid crystal in the total mass of the liquid crystal dimming layer is less than or equal to 2%; the ionic liquid crystal contains a biphenyl structure and a tetrahydropyrrole ring structure. By adding a small proportion of ionic liquid crystal which is compatible with the nematic liquid crystal, the liquid crystal dimming film has the characteristics of low cost, low driving voltage and high yellowing resistance.

Description

Technical Field

[0001] This invention relates to the field of liquid crystal dimming films, and more specifically, to a low-voltage driven liquid crystal dimming film resistant to yellowing. Background Technology

[0002] Liquid crystal dimming film is a smart dimming material based on liquid crystal technology. It changes the orientation of liquid crystal molecules by using an electric field to control the arrangement of liquid crystal molecules and adjust the light transmittance.

[0003] The liquid crystal dimming film consists of two transparent conductive films and a polymer liquid crystal layer in the middle. The polymer liquid crystal layer is formed by curing a prepolymer and liquid crystal. In the power-off state, the liquid crystal molecules are disordered, causing light to be unable to pass through, resulting in a milky white and opaque state. When electricity is applied, the liquid crystal molecules rearrange under the action of the electric field, allowing light to pass through, resulting in a transparent state.

[0004] Liquid crystal dimming films can be applied in fields such as architectural glass, automotive windshields, commercial projection, and medical devices. For example, in buildings, they can be used as smart curtains or heat insulation films; in automobiles, they can be used as privacy films or sunshades. However, currently, liquid crystal dimming films require a relatively high driving voltage, which limits their applications.

[0005] To achieve low-voltage drive, the industry offers several solutions. One approach is to add highly polar liquid crystals to reduce voltage. However, these highly polar liquid crystals are typically alkyne-based, which are not only expensive but also have poor stability and are prone to yellowing. Another approach involves changing the type or proportion of prepolymers, such as by adding polymerizable liquid crystals or fluoropolymer monomers to reduce voltage. However, polymerizable liquid crystals and fluoropolymer monomers are quite expensive; the amount of polymerizable liquid crystals added is generally greater than 2%, and the proportion of fluoropolymer monomers is even higher, resulting in higher costs. Yet another approach involves adding other components, such as nanoparticles like Fe3O4, TiO2, Fe2O3, Ag, and Au. However, because inorganic nanoparticles are incompatible with organic liquid crystals or polymers, this leads to decreased stability of the entire system and a tendency to yellow.

[0006] Therefore, there is a lack of technical solutions that can achieve low-voltage driven, yellowing-resistant liquid crystal dimming films at a lower cost. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention provides a liquid crystal dimming film with low-voltage driving and resistance to yellowing. The liquid crystal dimming film of this invention features low cost, low driving voltage, and high resistance to yellowing.

[0008] This invention provides a yellowing-resistant, low-voltage driven liquid crystal dimming film. The liquid crystal dimming film contains a liquid crystal dimming layer, which contains nematic liquid crystal, a polymer, and an ionic liquid crystal. The polymer accounts for 30%-70% of the total mass of the polymer and the nematic liquid crystal, and the ionic liquid crystal accounts for less than or equal to 2% of the total mass of the liquid crystal dimming layer. The ionic liquid crystal contains a biphenyl structure and a tetrahydropyrrole ring structure.

[0009] Preferably, the ionic liquid crystal is selected from at least one of the compounds shown in the following structures:

[0010] u and v each independently represent positive integers from 4 to 12; u and v can be the same or different; Z - The term refers to a pair of anions, wherein the pair of anions is an organic or inorganic anion, and the pair of anions is selected from bromide ions (Br₂). - ), iodide ions (I - ), thiocyanate ion (SCN) - ), hexafluorophosphate (PF6) - ), tetrafluoroborate (BF4) - ), Methylsulfonate (MeSO3) - or MsO - ), phenylsulfonate (PhSO3) - or PhsO - ), Toluenesulfonate (TsO) - or OTs - ), trifluoromethanesulfonate (TfO) - or OTf - ), bis(trifluoromethanesulfonyl)imide (TFSI) - or Tf2N - ), acetate (OAc) - or AcO - ), trifluoroacetate (TFA) - ), difluorosulfonyl imide (FSI) - ), tetraphenylborate (BPh4) - ) or nitrate (NO3) - One of the following: The parentheses in the above anions refer to abbreviations. For toluenesulfonate, this includes p-toluenesulfonate, o-toluenesulfonate, and m-toluenesulfonate. In the specific compounds of this application, such as =110, the toluenesulfonate is p-toluenesulfonate.

[0011] Preferably, u and v each independently represent positive integers from 4 to 11.

[0012] Preferably, the ionic liquid crystal is selected from at least one of the compounds shown in the following structures: .

[0013] Preferably, the ion-liquid crystal further contains at least one of the compounds shown in the following structures, wherein the compounds shown in the following structures contain at least one pyridine ring structure: ; p and q each independently represent positive integers from 6 to 16; p and q can be the same or different; X - The term refers to a pair of anions, wherein the pair of anions is an organic or inorganic anion, and the pair of anions is selected from one of the following: bromide ion, iodide ion, thiocyanate ion, hexafluorophosphate, tetrafluoroborate, methanesulfonate, phenylsulfonate, toluenesulfonate, trifluoromethanesulfonate, bis(trifluoromethanesulfonyl)imide, acetate, trifluoroacetate, bis(fluorosulfonyl)imide, tetraphenylborate, or nitrate.

[0014] k and j each independently represent positive integers from 4 to 14; k and j can be the same or different; Y - The term refers to a pair of anions, wherein the pair of anions is an organic or inorganic anion, and the pair of anions is selected from one of the following: bromide ion, iodide ion, thiocyanate ion, hexafluorophosphate, tetrafluoroborate, methanesulfonate, phenylsulfonate, toluenesulfonate, trifluoromethanesulfonate, bis(trifluoromethanesulfonyl)imide, acetate, trifluoroacetate, bis(fluorosulfonyl)imide, tetraphenylborate, or nitrate.

[0015] Preferably, the ion-liquid crystal further contains at least one of the compounds shown in the following structures: .

[0016] Preferably, the weight percentage of the total mass of the ion-liquid crystal and the liquid crystal dimming layer is in the range of 0.01-2%.

[0017] Preferably, the weight percentage of the total mass of the ion-liquid crystal and the liquid crystal dimming layer is in the range of 0.01-1%.

[0018] Preferably, the weight percentage of the total mass of the ion-liquid crystal and the liquid crystal dimming layer is in the range of 0.01-0.05%.

[0019] Preferably, the weight percentage of the ionic liquid crystal containing biphenyl and tetrahydropyrrole ring structures is not less than that of the ionic liquid crystal containing pyridine ring structures.

[0020] Preferably, the nematic liquid crystal contains at least one liquid crystal monomer with the structure shown in formula (I) below: ; Wherein, X and Y each independently represent a C1-C12 alkyl, C1-C12 alkoxy, cyano, isothiocyano or fluorine atom, ring A and ring B each independently represent a benzene ring, pyridine ring or cyclohexane ring; the hydrogen atoms on ring A and ring B can be replaced by fluorine atoms; m and n each independently represent integers from 0 to 4; L is an ester group or ether bond; a represents 0 or 1.

[0021] Preferably, the polymer contains at least one polymerizable group and at least one initiator; the polymerizable group is selected from at least one of acrylic groups, methacrylic groups, allyl groups, or epoxy groups; the initiator is a photoinitiator or a thermal initiator; the mass percentage of the initiator to the total mass of the liquid crystal dimming layer is 0.01-5%.

[0022] Preferably, the ion-liquid crystal is selected from one or two of BP-1-1, BP-1-2, BP-1-3, BP-1-4, BP-2-5, BP-2-6, BP-3-5 or BP-4-5; the weight percentage of the total mass of the ion-liquid crystal and the liquid crystal dimming layer is selected from one of 0.01%, 0.04%, 0.05%, 0.08%, 0.1%, 1% or 2%.

[0023] Preferably, the ion liquid crystal is composed of two liquid crystals selected from any combination of the following: a combination of BP-1-1 and BP-2-5 or a combination of BP-1-2 and BP-2-5.

[0024] Preferably, the ion liquid crystal is two liquid crystals selected from any of the following combinations: a combination of BP-1-1 and PP-1-18, a combination of BP-1-1 and P-2-7, a combination of BP-1-2 and P-2-7, or a combination of BP-1-2 and PP-1-18.

[0025] Compared with the prior art, the present invention has the following beneficial effects: By adding ion-based liquid crystals, the electrical properties of the liquid crystal dimming layer can be changed without altering its original optical properties, thereby reducing the driving voltage.

[0026] Ionic liquid crystals possess both ionic and liquid crystal properties. The amount added in this invention is low, resulting in minimal increase in product cost. The ionic liquid crystal containing biphenyl and tetrahydropyrrole ring structures of this invention has a structure very similar to nematic liquid crystals, exhibiting excellent compatibility and strong resistance to yellowing. Detailed Implementation

[0027] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the following description is provided in conjunction with embodiments.

[0028] Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0029] It should be noted that, unless otherwise specified, all figures used in this specification and claims to represent feature dimensions, quantities, and physical properties should be understood to be modified by the term "about" in all cases. Therefore, unless stated to the contrary, the numerical parameters listed in the foregoing specification and appended claims are approximations, and those skilled in the art can appropriately modify these approximations to obtain the desired characteristics using the teachings disclosed herein. Unless otherwise specified, "about" fluctuates within 5%. For example, but not limited to, a weight ratio less than or equal to 2% means a weight ratio less than or equal to 2.1%. A weight ratio of 2.05% is considered to meet the limitation of "weight ratio less than or equal to 2%", while a weight ratio of 2.15% is considered not to meet the limitation of "weight ratio less than or equal to 2%". The use of numerical ranges indicated by endpoints includes all numbers within that range and any range within that range; for example, 1 to 5 includes 1, 1.2, 1.4, 1.55, 2, 2.75, 3, 3.80, 4, and 5, etc.

[0030] The nematic liquid crystal of the present invention contains at least one liquid crystal monomer with the structure shown in formula (I) below: ; In this invention, X and Y independently represent C1-C12 alkyl, C1-C12 alkoxy, cyano, isothiocyano, or fluorine atoms; ring A and ring B independently represent benzene, pyridine, or cyclohexane rings; the hydrogen atoms on ring A and ring B can be replaced by fluorine atoms; m and n independently represent integers from 0 to 4; L is an ester group or an ether bond; and a represents 0 or 1. It is understood that other liquid crystals containing nematic liquid crystals should also fall within the scope of this invention, such as adding a chiral agent to a nematic liquid crystal to enable it to achieve the properties of a cholesteric liquid crystal, which is also within the scope of this invention.

[0031] The nematic liquid crystal of this invention can be commercially available or self-made, for example E7, E8, SLC1717, SLC7011, ZLI-3239 or C7, all of which are well known to those skilled in the art. In the embodiments of this invention, the nematic liquid crystal is a positive liquid crystal.

[0032] For example, the chemical composition of E7 has the following components and proportions:

[0033] For example, the chemical composition of E8 has the following components and proportions:

[0034] For example, but without limitation, liquid crystals can use the following components and proportions; for ease of description, this liquid crystal is abbreviated as LC2026:

[0035] The polymer of the present invention contains at least one polymerizable group and at least one initiator; the polymerizable group is selected from at least one of acrylic group, methacrylic group, allyl group or epoxy group; the initiator is a photoinitiator or a thermal initiator; the mass percentage of the initiator to the total mass of the liquid crystal dimming layer is 0.01-5%.

[0036] The polymers described in this invention may also contain polystyrene, polycarbonate, and thiol polymers. Regarding the type of initiator, it can be either a free radical initiator or a cationic initiator. Specific examples, but not limited to, include 2-hydroxy-2-methylphenylacetone (1173), 1-hydroxycyclohexylbenzophenone (184), benzoin dimethyl ether (651), 2,4,6-trimethylbenzoyl diphenylphosphine oxide (TPO), bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (819), and isopropylthioxanthraquinone (ITX).

[0037] This invention uses polymers, which can be commercially available or self-made. Commercially available polymers, such as NOA65, are widely used in the industry.

[0038] Homemade polymers, for example but not limited to, can use the components and proportions shown below.

[0039] Pentaerythritol tetra(3-mercaptopropionic acid) ester, in a proportion of 50-70%; 1,3,5-triallyl-1,3,5-triazine-2,4,6-trione (TAIC), in a proportion of 30-50%; 2-carboxyethyl acrylate, in a proportion of 5-10%; and 2-carboxyethyl methacrylate, in a proportion of 5-10%. Unless otherwise specified, the proportions in this invention are weight percentages.

[0040] As a formulation for a liquid crystal dimming film, it typically requires mixing followed by thermosetting or photocuring. Those skilled in the art will understand that the polymer in this invention is the uncured state. Since there is no solvent, the quality before and after curing can be considered unchanged. To achieve better results, spacers can be added. Specific Implementation Example 1 E7 liquid crystal and NOA65 were mixed in a 1:1 ratio and stirred thoroughly. With a total of 100 parts E7 liquid crystal and NOA65, 1 part (1%) of initiator TPO, 0.01 part (0.01%) of ion-liquid crystal, and 0.5 part (0.5%) of 20-micron glass microspheres were added. It is understandable that the feeding method and the actual proportions differ. When 0.01% of ion-liquid crystal is added according to the above proportions, it refers to 0.01% of the total mass of the nematic liquid crystal and polymer, not that the proportion of ion-liquid crystal in the entire formulation is 0.05%. Strictly speaking, the proportion of ion-liquid crystal in the formulation is less than 0.01%, approximately equal to 0.00985%. To achieve a total mass closer to 0.01%, add 0.0101 parts of ion-liquid crystal, and the calculated percentage of ion-liquid crystal in the total mass is approximately 0.009950%. Adding 0.0102 parts of ion-liquid crystal, the calculated percentage of ion-liquid crystal in the total mass is approximately 0.010048%. The ion-liquid crystal in this embodiment is BP-1-1.

[0042] After the above mixture is stirred evenly, it is rolled with an ITO-PET film to form a 20-micron film, which is then cured under ultraviolet light with an intensity of 6mW / cm2 and a wavelength of 365nm to obtain a sample for photoelectric performance testing. Specific Implementation Example 2 The same method as in Example 1 was used, except that the ion liquid crystal was replaced with BP-1-2. Specific Implementation Example 3 The same method as in Example 1 was used, except that the ion liquid crystal was replaced with BP-1-3. Specific Implementation Example 4 The same method as in Example 1 was used, except that the ion liquid crystal was replaced with BP-1-4. Specific Implementation Example 5 The same method as in Example 1 was used, except that the ion liquid crystal was replaced with BP-2-5. Specific Implementation Example 6 The same method as in Example 1 was used, except that the ion liquid crystal was replaced with BP-2-6. Specific Implementation Example 7 The same method as in Example 1 was used, except that the ion liquid crystal was replaced with BP-3-5. Specific Implementation Example 8 The same method as in Example 1 was used, except that the ion liquid crystal was replaced with BP-4-5. Specific Implementation Example 9 The same method as in Example 1 was used, except that the proportion of ion liquid crystal was changed to 0.05% of the total mass. Specific Implementation Example 10 The same method as in Example 1 was used, except that the proportion of ion liquid crystal was changed to 0.1% of the total mass. Specific Implementation Example 11 The same method as in Example 1 was used, except that the proportion of ion liquid crystal was changed to 1% of the total mass. Specific Implementation Example 12 The same method as in Example 1 was used, except that the proportion of ion liquid crystal was changed to 2% of the total mass. Specific Implementation Example 13 The same method as in Example 1 was used, except that the E7 liquid crystal and NOA65 were mixed in a ratio of 3:7. Specific Implementation Example 14 The same method as in Example 1 was used, except that the E7 liquid crystal and NOA65 were mixed in a 7:3 ratio. Specific Implementation Example 15 The same method as in Example 1 was used, except that one ion liquid crystal was replaced with two liquid crystals, namely BP-1-1 added at 0.05% of the total mass and BP-2-5 added at 0.05% of the total mass. Specific Implementation Example 16 The same method as in Example 1 was used, except that one ion liquid crystal was replaced with two liquid crystals: BP-1-1 was added at 0.07% of the total mass, and PP-1-18 was added at 0.03% of the total mass. Specific Implementation Example 17 The same method as in Example 1 was used, except that one ion liquid crystal was replaced with two liquid crystals: BP-1-1 was added at 0.07% of the total mass, and P-2-7 was added at 0.03% of the total mass. Specific Implementation Example 18 The self-made liquid crystal and self-made polymer were mixed in a 1:1 ratio and stirred until homogeneous. With a total of 100 parts of self-made liquid crystal and self-made polymer, 1 part (1%) of initiator TPO and 0.5 parts (0.5%) of 20-micron glass microspheres were added, followed by the addition of ion-soluble liquid crystal. In this embodiment, the ion-soluble liquid crystal was BP-1-1, and the amount added was 0.04% of the total mass.

[0060] After the above mixture is stirred evenly, it is rolled with an ITO-PET film to form a 20-micron film, which is then cured under ultraviolet light with an intensity of 6mW / cm2 and a wavelength of 365nm to obtain a sample for photoelectric performance testing.

[0061] The homemade liquid crystal used was LC2026. The components and proportions of the homemade polymer were as follows: pentaerythritol tetra(3-mercaptopropionic acid) ester, 50%; 1,3,5-triallyl-1,3,5-triazine-2,4,6-trione (TAIC), 40%; 2-carboxyethyl acrylate, 5%; and 2-carboxyethyl methacrylate, 5%. The proportions of the homemade polymers are by weight percentage. Specific Implementation Example 19 The same method as in Example 18 was used, except that the proportion of ion liquid crystal was changed to 0.08% of the total mass. Specific Implementation Example 20 The same method as in Example 18 was used, except that one type of ion liquid crystal was replaced with two types of ion liquid crystals, BP-1-1 and BP-2-5, with each type of ion liquid crystal accounting for 0.02%. Specific Implementation Example 21 The same method as in Example 18 was used, except that one type of ion liquid crystal was replaced with two types of ion liquid crystals, BP-1-2 and BP-2-5, with each type of ion liquid crystal accounting for 0.04%. Specific Implementation Example 22 The same method as in Example 18 was used, except that one type of ion liquid crystal was replaced with two types of ion liquid crystals, BP-1-2 and P-2-7, with BP-1-2 accounting for 0.05% and P-2-7 accounting for 0.05%. Specific Implementation Example 23 The same method as in Example 32 was used, except that one type of ion liquid crystal was replaced with two types of ion liquid crystals, BP-1-2 and PP-1-18, with BP-1-2 accounting for 0.05% and PP-1-18 accounting for 0.05%.

[0067] Comparative Example 1 The same method as in Example 1 was used, except that ion liquid crystal was not added.

[0068] Comparative Example 2 In the same manner as in Example 1, except that the proportion of ionic liquid crystal is changed to 3%.

[0069] Comparative Example 3 In the same manner as in Example 1, except that the ionic liquid crystal added is 1-dodecyl-3-methylimidazolium bromide.

[0070] Regarding the optoelectronic performance test, the driving voltage is defined as 90% of the highest transmittance. The present invention believes that a driving voltage below 36V is low, such a driving voltage is safe for the human body and can also reduce power consumption. The yellowing resistance is tested by two indicators. The index of yellowing 1 is the index of ultraviolet accelerated yellowing, which is defined as irradiated with ultraviolet light at 60°C, the irradiation intensity value is 0.76W / m2@340nm, and the yellowing index after 48 hours of irradiation. The index of yellowing 2 is the index of high-temperature accelerated yellowing, which is defined as the yellowing index after being placed in an oven at 100°C for 48 hours. A yellowing index less than or equal to 3.00 is considered qualified.

[0071] The test data of Examples 1-31 and Comparative Examples 1-3 are as follows.

[0072] It can be seen that the driving voltage without adding ionic liquid crystal is high. As long as the proportion of ionic liquid crystal is increased, the single driving voltage can be decreased, but it is not appropriate to blindly increase the proportion of ionic liquid crystal. Adding a high proportion of ionic liquid crystal results in a decrease in the performance of yellowing 1 and yellowing 2. Adding an ionic liquid crystal that is not of the present invention also results in a decrease in the performance of yellowing 1 and yellowing 2.

[0073] For the technical solution of the present invention, changing the type of ionic liquid crystal has little impact on the yellowing performance, and a small proportion of ionic liquid crystal can meet the requirement of reducing the driving voltage.

[0074] According to the comparative examples, it can be seen that not all ionic liquid crystals can achieve the same invention effect. The comparative example provides an ionic liquid crystal without a biphenyl structure and a pyrrolidine ring structure, and its stability test fails to meet the requirements.

[0075] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art. The present invention will not be limited to these embodiments shown herein, but only needs to conform to the principles and characteristics disclosed herein.

Claims

1. A low-voltage driven liquid crystal dimming film with anti-yellowing properties, characterized in that, The liquid crystal dimming film contains a liquid crystal dimming layer, which contains nematic liquid crystal, polymer, and ion liquid crystal. The polymer accounts for 30%-70% of the total mass of the polymer and nematic liquid crystal, and the ion liquid crystal accounts for less than or equal to 2% of the total mass of the liquid crystal dimming layer. The ion liquid crystal contains a biphenyl structure and a tetrahydropyrrole ring structure.

2. The liquid crystal dimming film according to claim 1, characterized in that, The ion-liquid crystal is selected from at least one of the compounds shown in the following structures: ； u and v each independently represent positive integers from 4 to 12; u and v can be the same or different; Z - The term refers to a pair of anions, wherein the pair of anions is an organic or inorganic anion, and the pair of anions is selected from one of the following: bromide ion, iodide ion, thiocyanate ion, hexafluorophosphate, tetrafluoroborate, methanesulfonate, phenylsulfonate, toluenesulfonate, trifluoromethanesulfonate, bis(trifluoromethanesulfonyl)imide, acetate, trifluoroacetate, bis(fluorosulfonyl)imide, tetraphenylborate, or nitrate.

3. The liquid crystal dimming film according to claim 3, characterized in that, The ion-liquid crystal is selected from at least one of the compounds shown in the following structures: 、 、 、 、 、 。 4. The liquid crystal dimming film according to claim 2 or 3, characterized in that, The ion-liquid crystal also contains at least one of the compounds shown in the following structures: 、 ； p and q each independently represent positive integers from 6 to 16; p and q can be the same or different; X - The term refers to a pair of anions, wherein the pair of anions is an organic or inorganic anion, and the pair of anions is selected from one of the following: bromide ion, iodide ion, thiocyanate ion, hexafluorophosphate, tetrafluoroborate, methanesulfonate, phenylsulfonate, toluenesulfonate, trifluoromethanesulfonate, bis(trifluoromethanesulfonyl)imide, acetate, trifluoroacetate, bis(fluorosulfonyl)imide, tetraphenylborate, or nitrate. k and j each independently represent positive integers from 4 to 14; k and j can be the same or different; Y - The term refers to a pair of anions, wherein the pair of anions is an organic or inorganic anion, and the pair of anions is selected from one of the following: bromide ion, iodide ion, thiocyanate ion, hexafluorophosphate, tetrafluoroborate, methanesulfonate, phenylsulfonate, toluenesulfonate, trifluoromethanesulfonate, bis(trifluoromethanesulfonyl)imide, acetate, trifluoroacetate, bis(fluorosulfonyl)imide, tetraphenylborate, or nitrate.

5. The liquid crystal dimming film according to claim 2 or 3, characterized in that, The ion-liquid crystal also contains at least one of the compounds shown in the following structures: 。 6. The liquid crystal dimming film according to claim 1, characterized in that, The nematic liquid crystal contains at least one liquid crystal monomer with the structure shown in formula (I) below: ； Wherein, X and Y each independently represent a C1-C12 alkyl, C1-C12 alkoxy, cyano, isothiocyano or fluorine atom, ring A and ring B each independently represent a benzene ring, pyridine ring or cyclohexane ring; the hydrogen atoms on ring A and ring B can be replaced by fluorine atoms; m and n each independently represent integers from 0 to 4; L is an ester group or ether bond; a represents 0 or 1.

7. The liquid crystal dimming film according to claim 1, characterized in that, The polymer contains at least one polymerizable group and at least one initiator; the polymerizable group is selected from at least one of acrylic groups, methacrylic groups, allyl groups or epoxy groups; the initiator is a photoinitiator or a thermal initiator; the mass percentage of the initiator to the total mass of the liquid crystal dimming layer is 0.01-5%.

8. The liquid crystal dimming film according to claim 2 or 3, characterized in that, The ion-liquid crystal is selected from one or two of BP-1-1, BP-1-2, BP-1-3, BP-1-4, BP-2-5, BP-2-6, BP-3-5 or BP-4-5; the weight percentage of the total mass of the ion-liquid crystal and the liquid crystal dimming layer is selected from one of 0.01%, 0.04%, 0.05%, 0.08%, 0.1%, 1% or 2%.

9. The liquid crystal dimming film according to claim 8, characterized in that, The ion liquid crystal is composed of two liquid crystals, selected from any combination of the following: a combination of BP-1-1 and BP-2-5 or a combination of BP-1-2 and BP-2-5.

10. The liquid crystal dimming film according to claim 8, characterized in that, The ion liquid crystal is of two types, selected from any of the following combinations: a combination of BP-1-1 and PP-1-18, a combination of BP-1-1 and P-2-7, a combination of BP-1-2 and P-2-7, or a combination of BP-1-2 and PP-1-18.

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