A photochromic device with improved durability and method ofmanufacturing the same

Abstract

The present invention relates to a photochromic film and a photosensitive photochromic device comprising the same, which eliminates the need for a sealing structure to prevent external exposure of the electrolyte and enables photochromic changes by visible light as well as ultraviolet light in response to external environmental changes. The structure is characterized by having a photochromic film or a photochromic film layer, wherein an electrolyte is hermetically sealed within an optically transparent polymer matrix between a pair of opposing substrate layers, and a photoelectronic material and a photochromic material are dispersed within the electrolyte.

Description

Technology Field

[0001] The present invention relates to a photochromic device and a method for manufacturing the same, and more specifically, to a photochromic device and a method for manufacturing the same in which a mixture of an optically transparent resin, an electrolyte, and a photoelectro-electrochromic composite layer dispersed in the electrolyte is applied between opposing substrates, and phase separation is performed by creating a difference in solubility between the resin and the electrolyte through drying, heat, and light, so that the photoelectro-electrochromic composite layer dispersed in the electrolyte is trapped in the continuous phase of the resin in the form of a droplet, thereby producing a photochromic device and a method for manufacturing the same in which the photoelectro-electrochromic material dispersed in the electrolyte has improved stable durability against external stimuli. Background Technology

[0002] Conventional organic photochromic devices achieve color change by altering the structure of organic materials through ultraviolet rays, thereby changing the wavelength of light absorbed; however, they are known not to photochromic in visible light and to have poor durability.

[0003] In addition, existing photochromic films based on organic photochromic materials have the disadvantage of being unusable inside vehicles because they change color due to ultraviolet rays, and there is a need to develop a photochromic film capable of photochromic under both ultraviolet and visible light.

[0004] There is an example in which a photoelectronic layer and an electrochromic material are combined to improve poor durability, thereby generating electrons in the photoelectronic layer by visible light and ultraviolet light, and realizing color change by reducing the electrochromic material with the generated electrons. Specifically, Registered Patent No. 10-2522644 discloses a photosensitive photochromic composite layer in which a reductive photochromic material and a photoelectronic layer are integrally formed to increase the color change efficiency of the stacked photoelectronic layer and the electrochromic material.

[0005] However, the photosensitive photochromic composite layer disclosed in this patent has a portion where the electrolyte is exposed to the outside. Since such external exposure weakens durability due to oxidation of the color-changing agent and evaporation of the solvent, it is essential to introduce a sealing structure, such as a sealing layer, to prevent external exposure of the electrolyte. Consequently, there was a problem requiring additional processing, and the structure including the disclosed photosensitive photochromic composite layer was insufficient to achieve effective photochromic effects in visible light as well as ultraviolet light. Prior art literature

[0006] Republic of Korea Registered Patent No. 10-2522644 Republic of Korea Published Patent Application No. 10-2017-0104269 Republic of Korea Published Patent Application No. 10-2018-0036276 The problem to be solved

[0007] Accordingly, the present invention was devised to solve the problems of the aforementioned prior art. The objective of the present invention is to provide a photochromic film that uses a liquid electrolyte without requiring an additional sealing structure and whose transmittance of a color-changing substance varies according to changes in the external environment, a photosensitive color-changing device equipped with such a photochromic film, and a method for manufacturing the same. means of solving the problem

[0008] To solve the aforementioned technical problem, the present invention provides a photosensitive colorimetric device comprising a colorimetric film composed of an electrolyte in which a photoelectronic material and a colorimetric material are dispersed within an optically transparent polymer matrix, and a colorimetric film according to the present invention between a pair of opposing substrate layers.

[0009] In addition, the present invention provides a method for manufacturing a photosensitive photochromic device having high photochromic efficiency and improved durability, wherein the electrolyte and the photoelectronic and photochromic materials dispersed in the electrolyte are coated between opposing substrates, and phase separation occurs by creating a difference in solubility between the resin and the electrolyte through a drying process, thereby hermetically sealing the electrolyte in which the photoelectronic and photochromic materials are dispersed in the continuous phase of the resin, so that the electrolyte and the photoelectronic and photochromic materials dispersed in the electrolyte exist in a stable state against changes in the external environment. Effects of the invention

[0010] According to the present invention, the color-changing film of the present invention is capable of photochromic light even in ultraviolet and visible light, thereby providing adaptive photochromic light in response to changes in the external environment.

[0011] According to the present invention, process costs can be reduced and the productivity of photosensitive colorimetric devices can be improved by eliminating the need to introduce an additional sealing structure while using a liquid electrolyte. Brief explanation of the drawing

[0012] FIG. 1 illustrates an embodiment according to the present invention, wherein an electrolyte is hermetically sealed on a continuous phase of resin (sealant) and a photoelectronic material (photoelectronic layer)-photochromic material (electrochromic layer) composite (composite layer) is dispersed within the electrolyte, and the structure of a photosensitive photochromic device including the photochromic film. FIG. 2 illustrates the structure of a photosensitive photochromic device as an embodiment according to the present invention, wherein an electrolyte in the form of a droplet is hermetically sealed on a continuous resin (sealant), and a photochromic film comprising one or more photoelectronic materials (photoelectronic layer)-photochromic materials (electrochromic layer) core-shell composites are dispersed within the electrolyte. FIG. 3 illustrates the structure of a photochromic film and a photosensitive photochromic device comprising the same, as an embodiment according to the present invention, wherein an electrolyte is hermetically sealed on a continuous phase of resin (sealant) and a mixture of a photoelectronic material and a photochromic material (electrochromic material) is dispersed within the electrolyte. Specific details for implementing the invention

[0013] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings.

[0014] This embodiment is provided to more fully explain the invention to those with average knowledge in the art, and the shape of the elements, the size of the elements, the spacing between elements, etc. in the drawings may be exaggerated or reduced to emphasize a clearer explanation.

[0015] In addition, in describing the embodiments, detailed descriptions of matters that are already obvious to a person skilled in the art, such as related known functions or known configurations, and are deemed likely to unnecessarily obscure the technical features of the present invention, will be omitted.

[0017] FIG. 1 is a cross-sectional view illustrating the structure of a photosensitive color-changing element (100) according to the present invention. Referring thereto, the photosensitive color-changing element (100) according to the present invention has a structure comprising a photochromic film (layer) (20) in which an electrolyte (31) is hermetically sealed within an optically transparent polymer matrix (resin) (30) between a pair of opposing substrate layers (10, 40), and a photoelectronic material (32) and a color-changing material (33) are dispersed within the electrolyte.

[0018] In other words, the photosensitive color-changing element (100) according to the present invention has a structure in which an optically transparent resin layer (30), i.e., a polymer matrix layer, exists between a pair of opposing substrate layers (10, 40), and an electrolyte (31) in which a composite composed of a photoelectron layer (32) and a color-changing layer (33) is dispersed is trapped in a continuous phase of the resin layer.

[0019] The photosensitive color-changing element according to the present invention, due to the photochromic film (layer) (20) having the structure described above, can maintain a stable state for the photoelectronic material and the color-changing material dispersed in the electrolyte from external stimuli, thereby providing high durability and also providing photochromic effects in response to changes in the external environment.

[0020] The substrate layer (10, 40) may be made of transparent plastic or glass with a light transmittance of 95% or more so that sunlight irradiated from the outside is transmitted into the inside. As transparent plastics, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), polypropylene (PP), polyimide (PI), and triacetylcellulose (TAC) may be used. The substrate layer (10, 40) is formed with a thickness of 10 μm to 5 mm. The substrate layer (10, 40) may be formed with a transparent electrode such as ITO, ZnO, or IZO so that discoloration and fading can be achieved by applying power at a desired time.

[0021] The optically transparent resin layer (30) is also called a polymer matrix layer and may include one or more selected from the group consisting of polyvinyl butyral (PVB), polysiloxane, and mixtures thereof. To dissolve the polymer forming the resin layer, ketones such as methyl ethyl ketone (MEK) and methyl isobutyl ketone (MIBK), esters such as ethyl acetate and butyl acetate, and solvents such as toluene, xylene, naphtha, gasoline, mineral spirit, crocene, cyclohexane, normal hexane, normal heptane, diisopropyl ether, hexyl ether, isopropyl laurate, isopropyl palmitate, isopropyl myristate, lyryl alcohol, etc. may be used.

[0022] In the resin layer, the polymer can be three-dimensionally cross-linked to form a matrix during the heat drying, curing, and photocuring processes.

[0023] If the resin layer (30) is formed to a thickness of 10 μm or less, it is difficult to form the terminal portion in the subsequent process. Although it can be formed to a thickness of 100 to 200 μm, there are problems such as reduced transmittance and increased cost, so it is preferably formed to a thickness of 10 to 100 μm.

[0024] The electrolyte (layer) (31) serves to provide a path for electron movement for the color change of the photosensitive color-changing film (20), more precisely, the photoelectronic material (layer) (32) and the color-changing material (layer) (33), and may be composed of a liquid electrolyte or a gel-polymer electrolyte, and may include a polymer precursor, a polyfunctional monomer, a solvent, a metal salt, a photosensitive ligand, a dye, a catalyst, a redox agent, a dispersant, a surfactant, etc.

[0025] The electrolyte (layer) (31) has a size that ensures uniform dispersion of the photoelectronic material (layer) (32) and the color-changing material (layer) (33), and is formed into droplet sizes of 0.5-10 µm that are difficult to identify with the naked eye.

[0026] In the case of liquid electrolytes, they may consist of a solvent, metal salt, photosensitive ligand, dye, catalyst, redox agent, dispersant, and surfactant, excluding the polymer precursor and polyfunctional monomer in gel polymer electrolytes.

[0027] In the case of a gel-polymer electrolyte, the polymer of the gel-polymer may be composed of a composition that can be cured by light or heat, or double-cured by light and heat.

[0028] Photocurable polymers or thermocurable polymers can be used as polymer precursors.

[0029] The photocurable polymer may be composed of polyurethane acrylic resin, polyepoxide acrylic resin, or a mixture thereof.

[0030] The thermosetting polymer may include one or more selected from the group consisting of a mixture of a hydroxyl-terminated acrylic resin and a diisocyanate, a mixture of an acid-terminated acrylic resin and a diglycidyl ether, a mixture of an amine-terminated acrylic resin and a diglycidyl ether, and mixtures thereof.

[0031] As a polyfunctional monomer, a monomer containing one (meth)acrylic group or two or more (meth)acrylic groups may be used. Monomers containing two or more (meth)acrylic groups may include ethylene glycol di(meth)acrylate, poly(ethylene glycol) di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, tri(propylene glycol) di(meth)acrylate, tris(2-(meth)acryloethyl) isocyanurate, trimethylolpropane tri(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol di(meth)acrylate, dipentaerythritol tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, etc.

[0032] As a solvent, one that does not dissolve the polymer matrix (resin), has a freezing point of -40°C or lower, a boiling point of 100°C or higher, a dielectric constant of 20 or higher, and a difference in refractive index from the polymer matrix of 0.02 or lower may be used, and may include one or more selected from the group consisting of, for example, alcohol-based solvents such as methanol, ethanol, n-propanol, isopropanol, n-butanol, 2-butanol, isobutanol, methoxymethanol, ethoxymethanol, methoxypropanol, etc.; nitrile-based solvents such as acetonitrile; amide-based solvents such as N-methyl-2-pyrrolidone, etc.; carbonate-based solvents such as ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, etc.; sulfide-based solvents such as diethyl sulfide, dipropyl sulfide, dibutyl sulfide, etc.; and mixtures thereof.

[0033] The cations of the metal salt within the electrolyte droplet move to the discolored substance to maintain charge balance when the discolored substance is reduced, and move back to the liquid electrolyte when it is decolorized, playing a role in balancing the charge.

[0034] The metal salt may include one or more selected from the group consisting of LiPF6, LiClO4, LiBF3, LiClO4, LiTFSI, LiFSI, LiOTf, Li2SO4, LiF, LiI, and mixtures thereof, but is not limited thereto.

[0035] The photosensitive ligand may include 1,4,5,8-naphthalenetetracarboxylic acid, 1,4,5,8-naphthalenetetracarboxylic acid anhydride, 1,8-naphthalic acid anhydride, 1-naphthoic acid, salicylic acid, salicylic acid derivatives, salicylaldehyde, salicylamide, naphthol blue-black or naphthol green B, etc.

[0036] As dyes, organo-metallic compound dyes, organic dyes, polymer dyes, and semiconductor nanoparticles may be used, for example, ruthenium (Ru) series organo-metallic compounds or cis-diisothiocyanatobis(2,2'-bipyridyl-4,4'-dicarboxylato ruthenium(II) bis(tetrabutylammonium) (N719)) may be used.

[0037] As catalysts, acetophenone-based compounds for photocuring include 2,2-dimethoxy-2-phenylacetophenone, 2,2'-diethoxyacetophenone, 2,2'-dibutoxyacetophenone, 2-hydroxy-2-methylpropiophenone, pt-butyltrichloroacetophenone, pt-butyldichloroacetophenone, 4-chloroacetophenone, 2,2'-dichloro-4-phenoxyacetophenone, 2-methyl-1-(4-(methylthio)phenyl)-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, and for heat setting, tin octoate, dibufiltin daurate, dibutyltin acetate, potassium acetate, Posassium octoate, dibutyltin mercaptide, dibutyltin thiocarboxylate, phenylmergyric propionate, lead oxide, calcium carbonate, ferric acetylacetonate, triethylenediamine, triethyleneamine, etc. may be used.

[0038] A redox agent in an electrolyte droplet can play a role in transferring charge to an oxidized photosensitive material (photosensitive layer) and a ligand or dye by exciting electrons when a reduced, colored discoloration material is oxidized and decolorized. Such redox agents may include one or more selected from the group consisting of iodine, ferrocene, thiourea, tampo derivatives, and mixtures thereof, but are not limited thereto.

[0039] Dispersants can serve to stabilize the dispersion of the core-shell structure of the chromogenic material and the photovoltaic layer, or the mixture of the chromogenic material and the photovoltaic layer, within a liquid electrolyte. Commercial products of the polyacrylate, polyacrylonitrile, styrene, polysiloxane, and copolymer series can be used as such dispersants.

[0040] Surfactants can play a role in stabilizing electrolyte droplets during polymer matrix formation. Examples of such surfactants include triisobutyltrimellitate, trinormalbutyltrimellitate, trioctyltrimellitate, and triisononyltrimellitate.

[0041] The photoelectronic material (layer) (32) can be composed of the photoelectronic material alone and may include a photosensitive ligand, dye, etc.

[0042] For example, the photoelectronic material (layer) (32) may include an inorganic metal oxide having an energy band gap in which electrons can be excited by external light such as sunlight. As inorganic metal oxides, titanium oxide (TiO2), zinc oxide (ZnO), tin oxide (SnO2), niobium oxide (Nb2O5), nickel oxide (NiO), silicon oxide (SiO2), and chromium oxide (Cr2O3) may be used. A photosensitive ligand or photosensitive dye that is responsive to sunlight may be adsorbed onto this inorganic metal oxide.

[0043] As photosensitive dyes, organo-metallic compound dyes, organic dyes, polymer dyes, and semiconductor nanoparticles may be used, for example, ruthenium (Ru) series organo-metallic compounds or cis-diisothiocyanatobis(2,2'-bipyridyl-4,4'-dicarboxylato ruthenium(II)bis(tetrabutylammonium) (N719)) may be used.

[0044] A photosensitive dye can be formed by immersing and adsorbing a solution of a predetermined concentration onto an inorganic metal oxide, and ethanol, iopranol, acetonitrile, or valeronitrile can be used as the solvent. At this time, if the amount of adsorbed photosensitive dye is low, the efficiency of electron generation by photosensitization decreases, and if the amount of adsorbed dye is high, the photosensitive dye is formed to be adsorbed at a level of 10 to 17% of the photoelectronic material, taking into consideration the film strength and conductivity of the photoelectrode.

[0045] As dyes, organo-metallic compound dyes, organic dyes, polymer dyes, and semiconductor nanoparticles may be used, for example, ruthenium (Ru) series organo-metallic compounds or cis-diisothiocyanatobis(2,2'-bipyridyl-4,4'-dicarboxylato ruthenium(II)bis(tetrabutylammonium) (N719)).

[0046] The photoelectronic material (layer) (32) can be configured to generate photoelectrons in the visible light as well as in the ultraviolet region, and is formed with a size of 20-200 nm.

[0047] The discoloration material (layer) (33) may consist of the discoloration material alone and may further include conductive inert materials such as carbon, platinum compounds, etc.

[0048] The photoelectronic material (layer) and the color-changing material (layer) according to the present invention can be manufactured in a composite form having a structure of a photoelectronic material (layer) core and a color-changing material (layer) shell, and can also be manufactured in a composite form with the compositions of the core and shell reversed.

[0049] As shown in FIG. 2, in the photochromic film (layer) (20) according to the present invention, one or more photoelectronic materials (layer) (32) and color-changing materials (layer) (33) may be included in the form of a core-shell structured composite.

[0050] When the photoelectronic material (layer) (32) and the color-changing material (layer) (33) are configured in the form of a core-shell composite structure, it is preferable to form them in nano-sized sizes to form a wider specific surface area. Accordingly, the photoelectronic material (layer) (32) surrounding the color-changing material (layer) (33) can be formed with a thickness of 20 to 200 nm, which is about 4 to 10 times the thickness of the color-changing material (layer) of 5 to 20 nm, so that electrons can be effectively excited when external light is irradiated, while light scattering does not increase.

[0051] The composite of the photoelectronic material (layer) and the photochromic material (layer) does not necessarily have to be a core-shell structure. For example, the composite of the photoelectronic material (layer) and the photochromic material (layer) may be configured in a form where the boundaries of each material or each layer are indistinct.

[0052] As shown in FIG. 3, the photoelectronic material (layer) (32) and the color-changing material (layer) (33) can be configured in a simple mixed form. One or more of the photoelectronic material (layer) (32) and the color-changing material (layer) (33) may each be included in the electrolyte.

[0053] In the present invention, the polymer of the polymer matrix and the polymer of the gel-electrolyte may be configured to be immiscible with each other so as to maintain the unique characteristics of each polymer.

[0054] In the present invention, the polymer of the polymer matrix and the polymer of the gel electrolyte may be configured to be insoluble in the same solvent.

[0055] When evaporating the solvent in the polymer matrix solution to induce phase separation between the polymer matrix and the solvent in the electrolyte, one or more solvents dissolved in the polymer matrix may be selected from the group consisting of ketones such as methyl ethyl ketone, esters such as ethyl acetate, and solvents with high polarity and low boiling points such as toluene, xylene, naphtha, gasoline, crocene, cyclohexane, normal hexane, normal heptane, diisopropyl ether, exyl ether, ethyl acetate, butyl acetate, isopropyl laurate, isopropyl palmitate, isopropyl myristate, methyl ethyl ketone, methyl isobutyl ketone, and lyryl alcohol, and mixtures thereof.

[0056] The electrolyte solvents are alcohol-based such as ethylene glycol, tetraglyme, polyethylene glycol dimethyl ether, polyethylene glycol, ethoxyethanol, etc.; nitrile-based such as hydroxypropionitrile, acetonitrile, propionitrile, methoxypropionitrile, oxydipropionitrile, butanedinitrile, pentanedinitrile, methylglutaronitrile, hexanedinitrile, acrylonitrile, etc.; and amide-based such as acetaamide, dimethylacetaamide, methylacetaamide, acetylthioacetaamide, acetylethylenediamide, dimethylaminophenol, benzamide, benzacetamide, benzamidomethylol, trifluoromethylbenzamide, dimethylformamide, etc. One or more solvents selected from the group consisting of mixtures thereof, solvents having a low freezing point, a high boiling point, and a high dielectric constant, such as cyclic carbonates like cyclopentanone, acetylbutyrolactone, gamma-butyrolactone, propylene carbonate, ethylene carbonate, tetrahydrofuran, dioxolane, etc.; linear carbonates like dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, diethyl ether, diethyl formate, methyl propionate, ethyl propionate, propyl propionate, etc.; sulfide solvents like sulfolane, methylsulfolane, dimethylsulfohan, diethyl sulfide, dipropyl sulfide, dibutyl sulfide, etc., etc., and mixtures thereof.

[0057] In the case where a polymer matrix is ​​mixed with an electrolyte solvent without a solvent, the above electrolyte solvent may be used when phase separation between the polymer matrix and the solvent in the electrolyte is induced by photocuring or thermal curing the electrolyte.

[0058] In the present invention, the ratio of the polymer matrix polymer to the solvent in the liquid electrolyte is 60:40 to 10:90 (polymer matrix polymer:solvent) based on weight, preferably 60:40 to 20:80, and more preferably 50:50. If the amount of the polymer matrix exceeds the above ratio, the amount of electrolyte involved in discoloration decreases, thereby reducing the variable range of transmittance, and if the amount of the polymer matrix falls short of the above ratio, the mechanical properties and sealing effect of the device deteriorate.

[0059] In the present invention, the ratio of the polymer matrix polymer to the solvent in the gel polymer electrolyte is 60:40 to 10:90 (polymer matrix polymer:solvent) based on weight, preferably 60:40 to 20:80, and more preferably 50:50. If the amount of the polymer matrix exceeds the above ratio, the amount of electrolyte involved in discoloration decreases, thereby reducing the variable range of transmittance, and if the amount of the polymer matrix falls short of the above ratio, the mechanical properties and sealing effect of the device deteriorate.

[0060] In the present invention, a color-changing material refers to a material whose transmittance of visible light or both visible light and infrared light changes simultaneously when it is reduced by accepting electrons or oxidized by losing electrons.

[0061] Color-changing materials include, but are not limited to, electrochromic materials, photochromic materials, or thermochromic materials.

[0062] The discoloration substance may be an inorganic or organic substance.

[0063] The inorganic chromogenic material may include one or more selected from the group consisting of WO3, TiO2, MoO3, V2O3, Nb2O3, or LixCoO2, CoOx, IrOx, LiNiOx, NiOx, and mixtures thereof. Using WO3 as the inorganic chromogenic material may be advantageous as it allows for the control of infrared transmittance.

[0064] Organic discoloration substances may include one or more selected from the group consisting of viologen, anthraquinone, phthalic acid ester, polyaniline, phenothiazine, fluorane, tri- or di-phenylamine derivatives and mixtures thereof.

[0066] Operating principle of photosensitive color change devices

[0067] The operating principle of the photochromic film according to the present invention and the photosensitive color-changing element including the same is as follows.

[0068] The principle of discoloration is that a photosensitive layer generates photoelectrons in response to solar energy, and these generated photoelectrons are injected into a reductive color-changing material—a substance that reduces the transmittance of visible and infrared light through reduction—while cationic metals within the electrolyte are also inserted to maintain electrical balance. In the absence of sunlight, the cationic metals within the reductive color-changing material revert to the original electrolyte, releasing electrons as well; consequently, the reductive color-changing material oxidizes and becomes decolorized.

[0069] According to the present invention, a photosensitive photochromic device including a photochromic film can be fabricated by following a process comprising: a) dissolving an optically transparent resin in a solvent to prepare a first mixture; b) dissolving an electrolyte, a photoelectronic material, and a photochromic material in a solvent to prepare a second mixture in which the photoelectronic material and the photochromic material are dispersed in the electrolyte; c) mixing the first mixture and the second mixture, applying the mixture onto a first substrate, and drying it; and d) laminating the second substrate onto the dried first substrate and then curing it.

[0070] According to the present invention, phase separation occurs between the resin and the electrolyte due to differences in solubility during the drying process, and accordingly, the electrolyte in which the photoelectronic material and the photochromic material are dispersed is hermetically sealed in the continuous phase of the resin. The photochromic film produced according to the present invention not only has high photochromic efficiency, but also improves the durability of the photosensitive photochromic device, as the electrolyte and the photoelectronic material and the photochromic material dispersed in the electrolyte exist in a stable state against changes in the external environment.

[0071] In another example of the present invention, phase separation occurs between the resin and the electrolyte due to a difference in solubility during the curing process, and accordingly, the electrolyte in which the photoelectronic material and the color-changing material are dispersed is hermetically sealed in the continuous phase of the resin. When phase separation occurs due to a difference in solubility during the curing process, a solvent capable of dissolving the resin is not required, and the electrolyte contains a curable polymer, an initiator, or a catalyst capable of curing within the electrolyte.

[0073] The present invention will be explained in detail below through examples and test examples. The examples and test examples are provided for the purpose of explaining an embodiment of the present invention, and the scope of the present invention is not limited by the examples.

[0075] [Preparation Example 1] Preparation of a photochromic film

[0076] Mixture A was prepared by dissolving polyvinyl butyral (PVB) and methyl ethyl ketone (MEK). Mixture B was prepared by dissolving urethane acrylate and TPO (2,4,6-trimethylbenzoyldiphenyl phosphine) in propylene carbonate (PC), then adding WO3 and TiO2 nanopowders and dispersing them using an ultrasonic disperser. Mixtures A and B were mixed in a weight ratio of 45:55, coated onto a PET substrate, dried at approximately 80°C for about 10 minutes, laminated onto another PET substrate, and then photocured with a high-pressure mercury lamp to produce a photochromic film that changes color upon exposure to external light.

[0078] [Preparation Example 2] Preparation of a photochromic film

[0079] Mixture A was prepared by dissolving polyvinyl butyral (PVB) and methyl ethyl ketone (MEK). Mixture B was prepared by dissolving epoxy acrylate, TPO (2,4,6-trimethylbenzoyldiphenyl phosphine), in propylene carbonate, adding WO3-TiO2 core-shell powder, and dispersing with an ultrasonic disperser. Mixtures A and B were mixed in a weight ratio of 3.5:1, coated onto a PET substrate, laminated onto another PET substrate, and then photocured with a high-pressure mercury lamp to produce a photochromic film that changes color upon exposure to external light.

[0081] [Examples and Comparative Examples] Preparation of photochromic films with different compositions

[0082] According to the manufacturing method of the photochromic film of the manufacturing example, photochromic films of each example and comparative example were manufactured with the material composition of Table 1 below (Unit: weight%).

[0083] [Table 1]

[0084]

[0086] [Test Example] Evaluation of Physical Properties of Photochromic Film

[0087] Haze, color transmittance, and decolorization transmittance were measured for each of the photochromic films of Examples 1 to 5 and Comparative Example 1 and are shown in Table 2.

[0088] Specifically, for the fabricated photochromic device, the transmittance was measured according to ASTM D1003 Haze and D65 light source standards using a KONIKA-MINOLTA CM-5 spectrophotometer. Subsequently, for the fabricated photochromic device, the color transmittance was measured by exposing it to a solar simulator manufactured by TNE for 30 minutes, and the decolorization transmittance was measured after storing it in a dark room for 120 minutes.

[0089] [Table 2]

[0090]

[0091] It was found that when the content exceeded a certain ratio, electrolyte droplets were formed, electrons generated in the photoelectron layer by light moved to the chromogenic material to cause coloring, and a decolorization reaction occurred as metal cations were detached in a dark room. Additionally, haze increased as the content of the polymer matrix increased. When the droplet polymer matrix was excessive, the content of droplets containing the chromogenic material decreased, resulting in a narrowed photochromic transmittance range.

[0092] In the case of Comparative Example 1, the polymer matrix was dissolved in the electrolyte solvent (PMMA), all materials were mixed, and the movement of electrons generated in the photoelectron layer to the color-changing material was restricted, so no photochromic occurred.

[0094] The present invention, as described above, is not limited to the disclosed embodiments and can be modified and varied in various ways without departing from the spirit and scope of the invention, as will be obvious to those skilled in the art. Accordingly, such variations or modifications should be understood as falling within the scope of the claims of the present invention. Explanation of the symbols

[0095] 10, 40 : Enter 20 : Photochromic film (layer) 30 : Polymer matrix (resin) 31: Electrolytes 32 : Photoelectronic material (layer) 33 : Discoloration material (layer) 100: Photosensitive colorimetric device

Claims

Claim 1 A photochromic film layer characterized in that an electrolyte in the form of a liquid or gel-polymer is hermetically sealed at multiple locations within an optically transparent cured polymer matrix, and a photoelectronic material and a photochromic material are dispersed in each of the electrolytes hermetically sealed at multiple locations, wherein the electrolyte is dissolved using a solvent that does not dissolve the polymer matrix, has a freezing point of -40°C or lower, a boiling point of 100°C or higher, a dielectric constant of 20 or higher, and a difference in refractive index from the polymer matrix of 0.02 or lower. Claim 2 A photochromic film layer according to claim 1, wherein the optically transparent polymer matrix comprises one or more polymers selected from the group consisting of polyvinyl butyral, polysiloxane, and mixtures thereof. Claim 3 delete Claim 4 delete Claim 5 A photochromic film layer according to claim 1, wherein the photoelectronic material and the photochromic material are in the form of a core-shell composite structure in which a shell composed of a photochromic material exists on a core composed of a photoelectronic material, or in the form of a core-shell composite structure in which a shell composed of a photoelectronic material exists on a core composed of a photochromic material. Claim 6 A photochromic film layer according to claim 5, wherein the core-shell structured composite has a diameter of 20 to 200 nm. Claim 7 A photochromic film layer according to claim 5, characterized in that one or more of the core-shell structured composites are included in the electrolyte. Claim 8 A photochromic film layer according to claim 1, characterized in that the photoelectronic material and the photochromic material are each dispersed independently. Claim 9 A photochromic film layer according to claim 1, characterized in that the ratio of the solvent constituting the electrolyte to the polymer matrix is ​​60:40 to 10:90 based on weight. Claim 10 A photosensitive color-changing element characterized by comprising a pair of substrate layers facing each other and a photochromic film layer according to any one of claims 1, 2, 5 to 9 between the substrate layers.

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