Suspended-particle dimming device, and preparation method therefor and use thereof

Abstract

The present application provides a suspended-particle dimming device, and a preparation method therefor and a use thereof. The suspended-particle dimming device comprises a first conductive base layer, a dimming layer, and a second conductive base layer which are sequentially stacked. The dimming layer comprises at least two sequentially nested sealing frame bodies. An accommodating cavity is formed between the first conductive base layer, the second conductive base layer, and the inner sealing frame body. The accommodating cavity is filled with a dimming material. The interior of at least one of the sealing frame bodies is provided with a plurality of uniformly distributed support particles. The present application solves the problems of high voltage, poor support, low adhesion, and non-uniform device formation in existing flexible dimming devices.

Description

A suspended particle dimming device, its fabrication method and application Technical Field

[0001] This application belongs to the field of dimming technology, and relates to a suspended particle dimming device, its preparation method and application. Background Technology

[0002] Since its development, suspended particle dimming technology (SPD) has achieved a high level of maturity in terms of formulation and device fabrication processes. Currently, SPD dimming devices mainly consist of a first transparent conductive layer, an SPD dimming layer, and a second transparent conductive layer. The SPD dimming layer primarily employs a three-phase separation process, utilizing the incompatibility principle between silicone, dispersion, and nanoparticles. This process involves emulsification and photopolymerization to form a solid composite layer with silicone as the support and the dispersion and nanoparticles as the color-changing components. Examples include J. Mater. Chem. A, 2018, 6, 24157-24165, patents CN219574554U, and US6900923B2.

[0003] Since the film formation process of SPD involves three-phase separation, solving the problem of effective separation of the three phases while ensuring the mechanical properties of the film has become a key challenge for the industrial production of SPD dimming films. Although this process has significant advantages in continuous roll-to-roll production, storage and transportation, arbitrary shape cutting, and device lightweighting, silicone has defects in its ability to block water and oxygen. Water vapor and oxygen can easily enter the structure, leading to potential stability issues in the device. In addition, since SPD dimming devices are essentially capacitor-structured devices, the adhesion between silicone, as the system support, and the substrate is not only weak, but it is also prone to current shunting, resulting in a very high driving voltage for the device (typically 110V to 220V), far exceeding the safe voltage.

[0004] Currently, the most convenient method to reduce driving voltage is to avoid current sharing, that is, to ensure that all electric fields effectively act on the polarization and rotation of nanoparticles in the SPD. Therefore, removing the organosilicon support in the bulk phase or increasing the effective resistance of the organosilicon support is an effective way to reduce the dimming driving voltage of the SPD. It can be observed from liquid crystal devices that PDLC (polymer dispersed liquid crystal) devices with polymer support structures require significantly higher voltages than liquid crystal devices without polymer support in the bulk phase. Therefore, simplifying the original SPD coating process to a device structure constructed with a border adhesive will effectively reduce the driving voltage required by the device.

[0005] However, despite decades of development, SPD dimming films still have many shortcomings. For example, SPD flexible devices using traditional methods with silicone as the support do not have sufficient adhesion between the dimming layer and the transparent conductive substrate. As a result, the dimming film can be structurally damaged by stress caused by bending, folding, and collision. Improvement methods, such as patents CN111100299A and US7791788, have not been very effective.

[0006] Furthermore, the presence of the silicone support distributes the current, resulting in a very high required driving voltage for the device, far exceeding the safe operating voltage, severely limiting its application. While traditional spacers can solve the high driving voltage problem, existing methods are more suitable for fabricating rigid devices. Using adhesive spacers is a common solution for liquid crystal displays (e.g., patent KR101107696B1), but this method relies on the process of melting and bonding the surface adhesive at high temperatures, which can easily lead to device defects. Moreover, this method is limited by the characteristics of the adhesive used to produce the spacers, resulting in low versatility and high cost, hindering widespread use. Summary of the Invention

[0007] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

[0008] This application provides a suspended particle dimming device, its preparation method and application. Its support structure is better, which avoids thickness changes or flow of dimming material when it is bent, and solves the problems of high voltage, low adhesion and uneven device forming of existing flexible dimming devices.

[0009] In a first aspect, this application provides a suspended particle dimming device, which includes a first conductive base layer, a dimming layer and a second conductive base layer stacked in sequence. The dimming layer includes at least two nested frame bodies. A receiving cavity is formed between the first conductive base layer, the second conductive base layer and the inner frame body. The receiving cavity is filled with dimming material. At least one frame body has a plurality of uniformly distributed support particles inside.

[0010] The dimming layer of the suspended particle dimming device provided in this application improves the structural support performance of the device by distributing supporting particles inside. Even when bent, the thickness of the dimming layer will not change or flow. At the same time, the multi-layer sealing frame structure is adopted, which on the one hand, avoids the organic small molecules in the dimming material from coming into contact with the uncured adhesive and causing mutual dissolution, thus preventing the adhesive from failing. On the other hand, it can also improve the adhesion to the conductive substrates on both sides, thereby making the device uniform in shape.

[0011] It should be noted that the cavity mentioned in this application refers to the enclosed space formed between the surrounding space of the innermost sealing frame body and the first and second conductive base layers on its upper and lower sides; the interior of the sealing frame body refers to the internal space of the sealing frame body itself.

[0012] In a preferred embodiment of this application, the at least two-layer sealing frame body includes a first sealing frame body and at least one second sealing frame body sleeved outside the first sealing frame body. The receiving cavity is formed between the first sealing frame body, the first conductive base layer and the second conductive base layer. The supporting particles are disposed inside at least the first sealing frame body.

[0013] Preferably, the material of the first sealing frame includes any one or a combination of at least two of the following: UV-curable silicone adhesive, thermosetting silicone adhesive, moisture-curing silicone adhesive, or UV-heated mixed silicone adhesive.

[0014] Preferably, the material of the second sealing frame includes any one or a combination of at least two of epoxy resin thermosetting adhesives, acrylic light-curing adhesives, or UV-heated mixed adhesives.

[0015] In this application, the first sealing frame can block the diffusion of small molecules of the dimming material, preventing them from coming into contact with uncured non-organosilicon adhesives and causing mutual solubility. The second sealing frame can adhere firmly to the first and second conductive substrates on both sides, improving the adhesion of the device.

[0016] In a preferred embodiment of this application, the supporting particles are also uniformly distributed within the accommodating cavity.

[0017] Preferably, the distribution density of the supporting particles is 1 to 100 particles / mm². 2 For example, it could be 1 particle / mm 2 3 pieces / mm 2 5 pieces / mm 2 8 pieces / mm 2 10 pieces / mm 2 20 pieces / mm 2 30 pieces / mm 2 40 pieces / mm 2 50 pieces / mm 2 60 pieces / mm 2 70 pieces / mm 2 80 pieces / mm 2 90 pieces / mm 2 95 pieces / mm 2 Or 100 pieces / mm 2 However, this does not apply to all values ​​listed; other unlisted values ​​within the same range also apply.

[0018] It should be noted that the distribution density of the supporting particles in this application is calculated based on the bottom surface of the cavity.

[0019] Preferably, the material of the supporting particles includes any one or a combination of at least two of the following: polymer resin, glass fiber, or inorganic materials.

[0020] Specifically, the supporting particles can be polystyrene, silicon dioxide, or SiO2-PS composite materials, etc.

[0021] Preferably, the shape of the supporting particle includes any one or a combination of at least two of the following: spherical, cylindrical, or cuboid.

[0022] Preferably, the diameter of the supporting particles is 2 to 100 μm, for example, it can be 2 μm, 5 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 80 μm, 90 μm or 100 μm, but it is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0023] Preferably, the color of the supporting particles includes any one or a combination of at least two of the following: colorless, gray, red, green, white, or black.

[0024] In a preferred embodiment of this application, the dimming layer is a flexible dimming layer, and the dimming material is a liquid material and / or a gel material.

[0025] Preferably, the dimming material includes any one or a combination of at least two of the following: SDP suspension, SPD suspension gel, liquid crystal composition, or electrochromic gel.

[0026] This application uses supporting particles to uniformly fix liquid or gel-state dimming materials between a first conductive substrate and a second conductive substrate, thereby obtaining a flexible dimming layer.

[0027] In a preferred embodiment of this application, at least one fixing coating layer is further provided between the first conductive substrate and the dimming layer, and / or between the second conductive substrate and the dimming layer.

[0028] This application achieves more uniform fixation of the supporting particles by setting a fixed coating, thereby ensuring that the dimming material is evenly distributed between the first conductive substrate and the second conductive substrate. Based on different methods of setting the fixed coating, this application provides the following three solutions: (1) The suspended particle dimming device consists of a first conductive substrate, a fixed coating, a dimming layer, and a second conductive substrate stacked sequentially; (2) The suspended particle dimming device consists of a first conductive substrate, a dimming layer, a fixed coating, and a second conductive substrate stacked sequentially; (3) The suspended particle dimming device consists of a first conductive substrate, a fixed coating, a dimming layer, a fixed coating, and a second conductive substrate stacked sequentially.

[0029] Preferably, the thickness of the fixed coating is 0.005 to 30 μm, for example, it can be 0.005 μm, 0.01 μm, 0.05 μm, 0.1 μm, 0.2 μm, 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 15 μm, 18 μm, 20 μm, 25 μm or 30 μm, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0030] Preferably, the fixing coating comprises any one or a combination of at least two of silicone, acrylic resin, polyurethane resin or epoxy resin.

[0031] In a preferred embodiment of this application, the first conductive base layer includes a first substrate, and a first conductive film is disposed on the surface of the first substrate near the dimming layer; the second conductive base layer includes a second substrate, and a second conductive film is disposed on the surface of the second substrate near the dimming layer.

[0032] That is, the suspended particle dimming device of this application is composed of a first substrate, a first conductive film, a dimming layer, a second conductive film and a second substrate stacked in sequence.

[0033] Preferably, the thickness of the first conductive film and the second conductive film are independently 50 to 500 μm, for example, 50 μm, 60 μm, 80 μm, 100 μm, 110 μm, 120 μm, 125 μm, 130 μm, 150 μm, 180 μm, 200 μm, 240 μm, 250 μm, 300 μm, 350 μm, 400 μm, 450 μm or 500 μm, but are not limited to the listed values. Other unlisted values ​​within this range are also applicable. More preferably, it is 125 to 250 μm.

[0034] Preferably, the first substrate and the second substrate are independently transparent substrates.

[0035] In this application, the first substrate and the second substrate can be plastic substrates, including but not limited to polyethylene terephthalate, polyvinyl alcohol film, polymethyl methacrylate, polyethylene, polypropylene, polyvinyl chloride, polyamide, chlorinated polypropylene, and their corresponding functional coated plastic films.

[0036] Preferably, the first conductive film and the second conductive film each independently comprise any one or a combination of at least two of the following: carbon-based conductive film, metal nanowire conductive film, or metal oxide film.

[0037] Secondly, this application provides a method for preparing the suspended particle dimming device described in the first aspect. The method includes: wet spraying supporting particles onto the surface of a first conductive substrate and / or a second conductive substrate, and after preparing at least two layers of sealing body, filling with dimming material to form a dimming layer, and curing the sealing body to obtain the suspended particle dimming device.

[0038] As a preferred embodiment of this application, the wet spraying includes: mixing the support particles with a solvent and adding the mixture into the feeding chamber of the powder spraying device, and spraying it onto the surface of the first conductive substrate or the second conductive substrate by means of circulating feeding.

[0039] Preferably, the supporting particles comprise any one or a combination of at least two of the following: polymer resin, glass fiber, or inorganic materials.

[0040] Preferably, the solvent includes any one or a combination of at least two of water, ethanol, isopropanol, acetone, N-methylpyrrolidone, ethyl acetate, or propylene glycol methyl ether acetate.

[0041] This application first mixes the support particles and solvent in a certain proportion as required, and adds them to the feeding chamber of the powder spraying device. Then, the heating, stirring, and circulation functions of the equipment are activated, and the powder spraying time and settling time are set. After the temperature inside the equipment chamber reaches the set value, the first conductive base layer and / or the second conductive base layer are placed into the powder spraying device chamber for powder spraying. The feeding chamber needs to employ continuous stirring and circulation to ensure uniform mixing of the support particles and solvent, which facilitates uniform distribution of the support particles later. The purpose of heating is to partially evaporate the solvent after spraying. The temperature setting range depends on the evaporation characteristics of the wet-spraying solvent, and the powder density can also be controlled by adjusting the powder spraying time and settling time.

[0042] Preferably, the method of manufacturing the sealing frame body includes: using adhesive material to sequentially form at least two layers of sealing frame body on the surface of a first conductive base layer or a second conductive base layer coated with supporting particles, and then performing a curing treatment.

[0043] Preferably, the adhesive material includes any one or a combination of at least two of the following: UV-curable silicone adhesives, epoxy resin thermosetting adhesives, acrylic light-curing adhesives, or UV-heated hybrid adhesives.

[0044] Preferably, the dimming material is filled using a vacuum injection method or a drop-in vacuum bonding method.

[0045] Specifically, this application provides the following two solutions for filling dimming materials, including:

[0046] Option 1: Vacuum Infusion Method

[0047] S1: Wet spraying of supporting particles is performed on the surface of the first conductive substrate to obtain an intermediate;

[0048] S2: At least two layers of sealing frame body are made on one side of the intermediate body sprayed with supporting particles. The sealing frame body has an injection port. Then, the second conductive base layer is attached and cured to obtain an empty box structure with a receiving cavity.

[0049] S3: Place the dimming material and the empty cell structure at different positions in the crystal filling device, and evacuate the vacuum. Then, bring the dimming material into contact with the empty cell structure and gradually release the pressure so that the dimming material is filled into the cavity to obtain the suspended particle dimming device.

[0050] Option 2: Drip Vacuum Adhesion Method

[0051] S01: Wet spraying of supporting particles is performed on the surface of the first conductive substrate to obtain an intermediate;

[0052] S02: At least two layers of sealing frame bodies are made on the side of the intermediate body that is sprayed with supporting particles. The sealing frame bodies are fully enclosed, and the dimming material is uniformly dripped into the space surrounded by the inner sealing frame bodies to obtain the filling box structure.

[0053] S03: Move the filling box structure and the second conductive base layer into the vacuum chamber, adsorb them into the device through vacuum, and then evacuate the vacuum to make the second conductive base layer adhere to the filling box structure. Then, perform a curing process on the sealing frame body to obtain the suspended particle dimming device.

[0054] It should be noted that this application does not impose specific limitations or special requirements on the selection and type of dimming materials, and any suspension known to those skilled in the art that can be used in dimming devices may be used.

[0055] In a preferred embodiment of this application, the preparation method further includes: before the wet spraying, applying a primer to the surface of the first conductive substrate and / or the second conductive substrate, and then drying it to form a fixed coating.

[0056] Taking thermally bonded silicone as an example, the base coat in this application can be applied using methods such as gravure roller coating, slot extrusion coating, or spraying, or gravure roller coating. By selecting different gravure roller mesh counts and solid contents according to the target thickness, a thinner, more uniform coating thickness can be obtained. Slot extrusion coating, by adjusting different solid contents, flow rates, and linear speeds, can also achieve different target thicknesses. The drying temperature can be set according to the actual amount of adhesive and the actual curing requirements. After drying, PET (polyethylene glycol terephthalate) or fluorinated release film can be selected for bonding and protection, depending on the adhesion strength of the fixed coating.

[0057] In addition, epoxy resin thermosetting adhesives, polyurethane resin adhesives, acrylic adhesives and other light-curing adhesives can all be prepared using the above coating methods. The difference lies in the curing method of different types of adhesives. Light-curing adhesives need to be first dried in a hot oven to evaporate the solvent, and then cured by UV light.

[0058] Thirdly, this application provides an application of the suspended particle dimming device described in the first aspect, wherein the suspended particle dimming device is used in flat glass or curved glass.

[0059] The suspended particle dimming device of this application has a supporting particle structure inside the dimming layer, which improves the support performance of the device. The thickness does not change when bent and there is no flow. Therefore, it can be effectively applied to flat or curved glass, such as car sunroofs, side windows, and various types of architectural glass.

[0060] The numerical range described in this application includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this application will not exhaustively list the specific point values ​​included in the range.

[0061] Compared with related technologies, the beneficial effects of this application are as follows:

[0062] This application provides a suspended particle dimming device, its preparation method, and its application. The dimming layer is supported by distributed particles, which improves the structural support performance of the device. Even when bent, the thickness of the dimming layer will not change or flow. At the same time, a multi-layer encapsulated body structure is adopted. On the one hand, it avoids the organic small molecules in the dimming material from coming into contact with the uncured adhesive and causing mutual solubility, which would lead to adhesive failure. On the other hand, it can also improve the adhesion to the conductive substrates on both sides. This solves the problems of high voltage, low adhesion, single preparation method, and uneven device molding in existing flexible dimming devices.

[0063] After reading and understanding the accompanying diagrams and detailed descriptions, the other aspects can be understood. Attached Figure Description

[0064] Figure 1 is a schematic diagram of the structure of the suspended particle dimming device provided in Embodiment 1 of this application.

[0065] Figure 2 is a top view of the first and second frame bodies provided in Embodiment 1 of this application.

[0066] Figure 3 is a top view of the first and second sealing frames provided in Embodiment 2 of this application.

[0067] Figure 4 is a top view of the first and second frame bodies provided in Embodiment 3 of this application.

[0068] Figure 5 is a schematic diagram of the structure of the suspended particle dimming device provided in Embodiment 6 of this application.

[0069] Figure 6 is a schematic diagram of the structure of the suspended particle dimming device provided in Embodiment 7 of this application.

[0070] Figure 7 is a schematic diagram of the drip-feed dimming material provided in Embodiment 10 of this application.

[0071] Figure 8 is a schematic diagram of the suspended particle dimming device provided in Comparative Example 1 of this application.

[0072] Figure 9 is a top view of the second enclosure provided in Comparative Example 1 of this application.

[0073] Figure 10 is a schematic diagram of the suspended particle dimming device of Embodiment 1 of this application applying pressure.

[0074] Figure 11 is a schematic diagram of the suspended particle dimming device of Embodiment 6 of this application applying pressure.

[0075] Wherein, 101-first substrate; 102-first conductive film; 103-supporting particles; 104-dimming material; 105-second substrate; 106-second conductive film; 107-fixing coating; 201-first sealing frame; 202-second sealing frame. Detailed Implementation

[0076] It should be understood that in the description of this application, the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are used solely for the convenience of describing this application and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0077] It should be noted that, in the description of this application, unless otherwise expressly specified and limited, the term "setup" should be interpreted broadly. For example, it can refer to a fixed connection, a detachable connection, or an integral connection; it can refer to a mechanical connection or an electrical connection; it can refer to a direct connection or an indirect connection through an intermediate medium; it can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0078] The technical solution of this application will be further described below with reference to the accompanying drawings and specific embodiments.

[0079] In one specific embodiment, this application provides a suspended particle dimming device, including a first conductive base layer, a dimming layer and a second conductive base layer stacked sequentially. The dimming layer includes at least two nested frame bodies. A receiving cavity is formed between the first conductive base layer, the second conductive base layer and the inner frame body. The receiving cavity is filled with dimming material. At least one frame body has a plurality of uniformly distributed support particles disposed inside it.

[0080] In some embodiments, the at least two layers of the sealing frame body include a first sealing frame body and at least one second sealing frame body sleeved outside the first sealing frame body. The receiving cavity is formed between the first sealing frame body, the first conductive base layer and the second conductive base layer. The supporting particles are disposed inside at least the first sealing frame body.

[0081] In some embodiments, the material of the first sealing frame includes any one or a combination of at least two of UV-curable silicone adhesives, thermosetting silicone adhesives, moisture-curing silicone adhesives, or UV-heated hybrid silicone adhesives. The material of the second sealing frame includes any one or a combination of at least two of epoxy resin thermosetting adhesives, acrylic UV-curable adhesives, or UV-heated hybrid adhesives. In this application, the first sealing frame can block the diffusion of small molecules of the dimming material, preventing them from coming into contact with uncured non-silicone adhesives and causing mutual solubility. The second sealing frame can adhere firmly to the first and second conductive substrates on both sides, improving the adhesion of the device.

[0082] In some embodiments, the supporting particles are also uniformly distributed within the receiving cavity. The distribution density of the supporting particles is 1–100 particles / mm². 2 The supporting particles are made of any one or a combination of at least two of the following: polymer resin, glass fiber, or inorganic materials. Specifically, the supporting particles can be polystyrene, silica, or SiO2-PS composite materials, etc. The shape of the supporting particles includes any one or a combination of at least two of the following: spherical, cylindrical, or cuboid. The diameter of the supporting particles is 2–100 μm. The color of the supporting particles includes any one or a combination of at least two of the following: colorless, gray, red, green, white, or black.

[0083] In some embodiments, the dimming layer is a flexible dimming layer, and the dimming material is a liquid material and / or a gel material. This application uses supporting particles to uniformly fix the liquid or gel-state dimming material between a first conductive substrate and a second conductive substrate, thereby obtaining a flexible dimming layer. Specifically, the dimming material includes any one or a combination of at least two of SDP suspension, SPD suspension gel, liquid crystal composition, or electrochromic gel. Exemplarily, the dimming material can be a suspended particle dispersion disclosed in CN112731722A, or a suspended particle dispersion disclosed in J. Mater. Chem. A, 2018, 6, 24157-24165, or other suspended particle dispersions well known to those skilled in the art; this application does not specifically limit its application in this regard.

[0084] In some embodiments, at least one fixing coating layer is further provided between the first conductive substrate and the dimming layer, and / or between the second conductive substrate and the dimming layer. The thickness of the fixing coating layer is 0.005 to 30 μm. This application can more uniformly fix the supporting particles by setting the fixing coating layer, thereby making the dimming material uniformly distributed between the first conductive substrate and the second conductive substrate. This application provides the following three schemes based on different ways of setting the fixing coating layer: (1) The suspended particle dimming device is composed of a first conductive substrate, a fixing coating layer, a dimming layer and a second conductive substrate stacked in sequence; (2) The suspended particle dimming device is composed of a first conductive substrate, a dimming layer, a fixing coating layer and a second conductive substrate stacked in sequence; (3) The suspended particle dimming device is composed of a first conductive substrate, a fixing coating layer, a dimming layer, a fixing coating layer and a second conductive substrate stacked in sequence.

[0085] The fixing coating comprises any one or a combination of at least two of silicone, acrylic resin, polyurethane resin, or epoxy resin. This application does not specifically limit the curing method of the fixing coating; it can be any curing technology well known to those skilled in the art, including but not limited to thermosetting, UV curing, moisture curing, and peroxide curing. It is understood that other curing technologies disclosed in related technologies or not disclosed in new technologies can also be used in this application.

[0086] In some embodiments, the first conductive base layer includes a first substrate, and a first conductive film is disposed on the surface of the first substrate near the dimming layer; the second conductive base layer includes a second substrate, and a second conductive film is disposed on the surface of the second substrate near the dimming layer. That is, the suspended particle dimming device of this application is composed of a first substrate, a first conductive film, a dimming layer, a second conductive film, and a second substrate stacked sequentially. The thickness of the first conductive film and the second conductive film is independently 50–500 μm, preferably 125–250 μm. The first substrate and the second substrate are independently transparent substrates. Specifically, the first substrate and the second substrate can be plastic substrates, including but not limited to polyethylene terephthalate, polyvinyl alcohol film, polymethyl methacrylate, polyethylene, polypropylene, polyvinyl chloride, polyamide, chlorinated polypropylene, and their corresponding functional coated plastic films. The first conductive film and the second conductive film independently include any one or a combination of at least two of carbon-based conductive films, metal nanowire conductive films, or metal oxide films. The carbon-based conductive films described in this application include, but are not limited to, graphene conductive films, carbon nanotube conductive films, and graphyne conductive films. The metal nanowire conductive films include, but are not limited to, silver nanowire conductive films and copper nanowire conductive films. The metal oxide films include, but are not limited to, indium tin oxide, indium oxide, tin oxide, zinc oxide, and mixtures of other metal oxides.

[0087] In another specific embodiment, this application provides a method for preparing a suspended particle dimming device according to a specific embodiment. The preparation method includes: wet spraying supporting particles onto the surface of a first conductive substrate and / or a second conductive substrate, and after preparing at least two layers of sealing body, filling with dimming material to form a dimming layer, and curing the sealing body to obtain a suspended particle dimming device.

[0088] In some embodiments, the wet spraying includes: mixing support particles with a solvent, adding the mixture to the feeding chamber of the powder spraying device, and spraying it onto the surface of the first conductive substrate or the second conductive substrate through a circulating feeding method. Specifically, the support particles include any one or a combination of at least two of polymer resin, glass fiber, or inorganic materials; the solvent includes any one or a combination of at least two of water, ethanol, isopropanol, acetone, N-methylpyrrolidone, ethyl acetate, or propylene glycol methyl ether acetate. In this application, the support particles and solvent are first mixed in a certain proportion and added to the feeding chamber of the powder spraying device. Then, the heating, stirring, and circulation functions of the equipment are turned on, and the powder spraying time and settling time are set. After the temperature inside the equipment chamber reaches the set value, the first conductive substrate and / or the second conductive substrate are placed into the cavity of the powder spraying device for powder spraying. The feeding chamber needs to use continuous stirring and circulating feeding to ensure that the support particles and solvent are mixed evenly, which is beneficial for achieving uniform distribution of support particles in the later stage. The purpose of heating is to partially evaporate the solvent after it is sprayed out. The temperature setting range depends on the evaporation characteristics of the wet-sprayed solvent. The powder density can also be controlled by adjusting the powder spraying time and settling time. Since silicone adhesives have a certain degree of adhesion after curing, the support particles can be sprayed after curing. However, epoxy resins, polyurethanes, and acrylics do not have adhesive surfaces after curing. If support particles are sprayed after curing, they will not be able to be fixed. Therefore, the support particles need to be evenly sprayed onto the conductive substrate surface before curing the coating.

[0089] In some embodiments, the frame body is manufactured by: sequentially forming at least two layers of the frame body on the surface of a first conductive base layer or a second conductive base layer coated with supporting particles using an adhesive material, and then performing a curing process. The adhesive material includes any one or a combination of at least two of the following: UV-curable silicone adhesives, epoxy resin thermosetting adhesives, acrylic photocurable adhesives, or UV-heated mixed adhesives.

[0090] In some embodiments, the dimming material is filled using either a vacuum infusion method or a drop-in vacuum bonding method. The vacuum infusion method is suitable for the fabrication of small-sized products, while the drop-in vacuum bonding method is suitable for the fabrication of large-sized products. Specifically, this application provides the following two methods for filling the dimming material:

[0091] Option 1: Vacuum Infusion Method

[0092] S1: Wet spraying of supporting particles is performed on the surface of the first conductive substrate to obtain an intermediate;

[0093] S2: At least two layers of sealing frame body are made on one side of the intermediate body sprayed with supporting particles. The sealing frame body has an injection port. Then, the second conductive base layer is attached and cured to obtain an empty box structure with a receiving cavity.

[0094] S3: Place the dimming material and the empty cell structure at different positions in the crystal filling device, and evacuate the vacuum. Then, bring the dimming material into contact with the empty cell structure and gradually release the pressure so that the dimming material is filled into the cavity to obtain the suspended particle dimming device.

[0095] Option 2: Drip Vacuum Adhesion Method

[0096] S01: Wet spraying of supporting particles is performed on the surface of the first conductive substrate to obtain an intermediate;

[0097] S02: At least two layers of sealing frame bodies are made on the side of the intermediate body that is sprayed with supporting particles. The sealing frame bodies are fully enclosed, and the dimming material is uniformly dripped into the space surrounded by the inner sealing frame bodies to obtain the filling box structure.

[0098] S03: Move the filling box structure and the second conductive base layer into the vacuum chamber, adsorb them into the device through vacuum, and then evacuate the vacuum to make the second conductive base layer adhere to the filling box structure. Then, perform a curing process on the sealing frame body to obtain the suspended particle dimming device.

[0099] In some embodiments, the preparation method further includes: before the wet spraying, applying a primer to the surface of the first conductive substrate and / or the second conductive substrate, and then drying it to form a fixed coating.

[0100] Taking thermosetting organic silicone as an example, the base coat in this application can be applied using methods such as gravure roller coating, slot extrusion coating, or spraying, or gravure roller coating. By selecting different gravure roller mesh counts and solid contents according to the target thickness, a thinner, more uniform coating thickness can be obtained. Slot extrusion coating, by adjusting different solid contents, flow rates, and linear speeds, can also achieve different target thicknesses. The drying temperature can be set according to the actual amount of adhesive and the actual curing requirements. After drying, PET or fluoropolymer release films can be used for bonding and protection, depending on the adhesion strength of the fixed coating. Furthermore, epoxy resin thermosetting adhesives, polyurethane resins, or acrylic UV-curing adhesives can all be prepared using the above coating methods. The difference lies in the curing method; UV-curing adhesives require first undergoing a heat oven for solvent evaporation, followed by UV light curing.

[0101] In some embodiments, the preparation method further includes plasma treatment of the surfaces of the first conductive substrate and / or the second conductive substrate to remove residual organic matter on the surface and simultaneously activate the surface.

[0102] Example 1

[0103] This embodiment provides a suspended particle dimming device, denoted as b1, as shown in Figures 1 and 2. Specifically, it includes a first substrate 101, a first conductive film 102, a flexible dimming layer, a second conductive film 106, and a second substrate 105, stacked sequentially. The first conductive film 102 and the second conductive film 106 are both 200 μm thick and are both indium tin oxide (ITO) conductive films. The flexible dimming layer includes a first sealing frame 201 and a second sealing frame 202 nested sequentially. A cavity is formed between the first conductive substrate, the second conductive substrate, and the first sealing frame 201, filled with a dimming material 104. The cavity and the interior of the first sealing frame 201 are filled with uniformly distributed spherical support particles 103. The first sealing frame 201 is made of a UV-curable silicone adhesive to block the diffusion of small molecules of the dimming material 104. The second sealing frame 202 is made of an epoxy resin thermosetting adhesive to firmly bond the first conductive film 102 and the second conductive film 106.

[0104] The fabrication method of the suspended particle dimming device in this embodiment includes the following steps:

[0105] (1) A first substrate 101 having a first conductive film 102 and a second substrate 105 having a second conductive film 106 are provided, and the first conductive film 102 and the second conductive film 106 are subjected to plasma treatment.

[0106] (2) The supporting particles 103 are mixed with the solvent in a certain proportion and added to the feeding chamber of the powder spraying device. At the same time, they are heated and stirred, and the powder is sprayed onto the surface of the first conductive film 102 by circulating feeding, so that the supporting particles 103 are evenly distributed on the first conductive film 102 to obtain the intermediate.

[0107] (3) Two layers of first sealing frame 201 and second sealing frame 202 are sequentially made on the side of the intermediate body sprayed with support particles 103, and the first sealing frame 201 and the second sealing frame 202 are provided with injection ports. Then the second substrate 105 is bonded and cured to obtain an empty box structure with a receiving cavity.

[0108] (4) Place the dimming material 104 and the empty cell structure in different positions in the crystal filling device, and continuously evacuate for more than 30 minutes. Then, bring the dimming material 104 into contact with the empty cell structure and gradually release the pressure so that the dimming material 104 is injected into the cavity to obtain the suspended particle dimming device.

[0109] The dimming material 104 used in this embodiment is the suspended particle dispersion disclosed in CN112731722A. Its specific raw materials and preparation methods are as described in CN112731722A, and will not be repeated here.

[0110] Example 2

[0111] This embodiment provides a suspended particle dimming device, denoted as b2, as shown in Figure 3. The difference from Embodiment 1 is that the second enclosure 202 is also provided with supporting particles 103. That is, supporting particles 103 are provided in the accommodating cavity, the first enclosure 201, and the second enclosure 202. The remaining structure, parameters, materials and preparation methods are the same as in Embodiment 1.

[0112] Example 3

[0113] This embodiment provides a suspended particle dimming device, denoted as b3, as shown in Figure 4. The difference from Embodiment 1 is that the first enclosure 201 does not have supporting particles 103 inside, while the second enclosure 202 has supporting particles 103 inside. That is, supporting particles 103 are provided in the accommodating cavity and the second enclosure 202. The remaining structure, parameters, materials and preparation methods are the same as in Embodiment 1.

[0114] Example 4

[0115] This embodiment provides a suspended particle dimming device, denoted as b4. The difference from Embodiment 1 is that the first sealing frame 201 and the second sealing frame 202 are both made of UV-curable silicone adhesive. The remaining structure, parameters, materials and preparation methods are the same as in Embodiment 1.

[0116] Example 5

[0117] This embodiment provides a suspended particle dimming device, denoted as b5. The difference from Embodiment 1 is that the first sealing frame 201 and the second sealing frame 202 are both made of epoxy resin thermosetting adhesive. The remaining structure, parameters, materials and preparation methods are the same as in Embodiment 1.

[0118] Example 6

[0119] This embodiment provides a suspended particle dimming device, denoted as b6, as shown in Figure 5. The difference from Embodiment 1 is that a fixed coating layer 107 is provided between the first conductive film 102 and the flexible dimming layer, and between the second conductive film 106 and the flexible dimming layer. The remaining structure and parameters are the same as in Embodiment 1.

[0120] The fabrication method of the suspended particle dimming device in this embodiment includes the following steps:

[0121] (1) A first substrate 101 having a first conductive film 102 and a second substrate 105 having a second conductive film 106 are provided, and the first conductive film 102 and the second conductive film 106 are subjected to plasma treatment.

[0122] (2) The surface of the first conductive film 102 and the second conductive film 106 is coated with silicone by slit extrusion coating and then dried to form a fixed coating 107.

[0123] (3) The supporting particles 103 are mixed with the solvent in a certain proportion and added to the feeding chamber of the powder spraying device. At the same time, they are heated and stirred, and the powder is sprayed onto the surface of the first conductive film 102 by circulating feeding, so that the supporting particles 103 are evenly distributed on the fixed coating 107 to obtain the intermediate.

[0124] (4) Two layers of first sealing frame 201 and second sealing frame 202 are sequentially made on the side of the intermediate body sprayed with support particles 103, and the first sealing frame 201 and the second sealing frame 202 are provided with injection ports. Then the second substrate 105 is bonded and cured to obtain an empty box structure with a receiving cavity.

[0125] (5) Place the dimming material 104 and the empty cell structure in different positions in the crystal filling device, and continuously evacuate for more than 30 minutes. Then, bring the dimming material 104 into contact with the empty cell structure and gradually release the pressure so that the dimming material 104 is injected into the cavity to obtain the suspended particle dimming device.

[0126] Example 7

[0127] This embodiment provides a suspended particle dimming device, which differs from Embodiment 6 in that, as shown in Figure 6, only a fixed coating layer 107 is provided between the first conductive film 102 and the flexible dimming layer, while the remaining structure, parameters, materials and preparation methods are the same as in Embodiment 6.

[0128] Example 8

[0129] This embodiment provides a suspended particle dimming device, which differs from Embodiment 6 in that: only a fixed coating layer 107 is provided between the second conductive film 106 and the flexible dimming layer, while the remaining structure, parameters, materials and preparation methods are the same as in Embodiment 6.

[0130] Example 9

[0131] This embodiment provides a suspended particle dimming device, which differs from Embodiment 6 in that the raw material for preparing the fixed coating 107 is epoxy resin, while the rest of the structure and parameters are the same as in Embodiment 6.

[0132] The fabrication method of the suspended particle dimming device in this embodiment includes the following steps:

[0133] (1) A first substrate 101 having a first conductive film 102 and a second substrate 105 having a second conductive film 106 are provided, and the first conductive film 102 and the second conductive film 106 are subjected to plasma treatment.

[0134] (2) Epoxy resin is coated on the surfaces of the first conductive film 102 and the second conductive film 106 by slit extrusion coating.

[0135] (3) The supporting particles 103 are mixed with the solvent in a certain proportion and added to the feeding chamber of the powder spraying device. At the same time, they are heated and stirred, and the powder is sprayed onto the surface of the first conductive film 102 by circulating feeding, so that the supporting particles 103 are evenly distributed on the epoxy resin. The epoxy resin is then dried and cured to form a fixed coating 107, thus obtaining an intermediate.

[0136] (4) Two layers of first sealing frame 201 and second sealing frame 202 are sequentially made on the side of the intermediate body sprayed with support particles 103, and the first sealing frame 201 and the second sealing frame 202 are provided with injection ports. Then the second substrate 105 is bonded and cured to obtain an empty box structure with a receiving cavity.

[0137] (5) Place the dimming material 104 and the empty cell structure in different positions in the crystal filling device, and continuously evacuate for more than 30 minutes. Then, bring the dimming material 104 into contact with the empty cell structure and gradually release the pressure so that the dimming material 104 is injected into the cavity to obtain the suspended particle dimming device.

[0138] Example 10

[0139] This embodiment provides a suspended particle dimming device, denoted as b7. Its preparation method is different from that of Embodiment 1, but its structure, parameters and materials are the same as those of Embodiment 1.

[0140] The fabrication method of the suspended particle dimming device in this embodiment includes the following steps:

[0141] (1) A first substrate 101 having a first conductive film 102 and a second substrate 105 having a second conductive film 106 are provided, and the first conductive film 102 and the second conductive film 106 are subjected to plasma treatment.

[0142] (2) The surface of the first conductive film 102 and the second conductive film 106 is coated with silicone by slit extrusion coating and then dried to form a fixed coating 107.

[0143] (3) The supporting particles 103 are mixed with the solvent in a certain proportion and added to the feeding chamber of the powder spraying device. At the same time, they are heated and stirred, and the powder is sprayed onto the surface of the first conductive film 102 by circulating feeding, so that the supporting particles 103 are evenly distributed on the fixed coating 107 to obtain the intermediate.

[0144] (4) Two layers of first sealing frame 201 and second sealing frame 202 are sequentially made on the side of the intermediate body sprayed with supporting particles 103. Both the first sealing frame 201 and the second sealing frame 202 are fully enclosed, as shown in Figure 7. The dimming material 104 is uniformly dripped into the space surrounded by the first sealing frame 201 located on the inner side. The total amount of liquid dimming material 104 is the same as the total amount required by the size of the first sealing frame 201, thus obtaining the filling box structure.

[0145] (5) Move the filling box structure and the second conductive base layer into the vacuum chamber, adsorb them in the device by vacuum, and evacuate the vacuum so that the second substrate 105 with the second conductive film 106 is attached to the filling box structure. Then, perform the curing treatment of the first sealing frame 201 and the second sealing frame 202 to obtain the suspended particle dimming device.

[0146] Example 11

[0147] This embodiment provides a suspended particle dimming device, denoted as b8. The difference from Embodiment 1 is that the material of the second sealing frame 202 is acrylic photocurable adhesive, while the rest of the structure, parameters, materials and preparation method are the same as in Embodiment 1.

[0148] Example 12

[0149] This embodiment provides a suspended particle dimming device, denoted as b9. The difference from Embodiment 1 is that the material of the second sealing frame 202 is a UV-heated mixed adhesive, while the rest of the structure, parameters, materials and preparation method are the same as in Embodiment 1.

[0150] Comparative Example 1

[0151] This comparative example provides a suspended particle dimming device, denoted as a1, as shown in Figures 8 and 9. The difference from Example 1 is that the first enclosure 201 is not provided, and the second enclosure 202 contains supporting particles 103. The remaining structure, parameters, materials and preparation methods are the same as in Example 1.

[0152] Comparative Example 2

[0153] This comparative example provides a suspended particle dimming device, denoted as a2. The difference between this device and Example 1 is that a second enclosure 202 is not provided. The remaining structure, parameters, materials, and preparation method are the same as in Example 1.

[0154] Comparative Example 3

[0155] This comparative example provides an organosilicon-supported SPD device disclosed in J. Mater. Chem. A, 2018, 6, 24157-24165, denoted as a3.

[0156] Comparative Example 4

[0157] This comparative example provides a suspended particle dimming device, denoted as a4. The difference from Example 1 is that no supporting particles 103 are set in the flexible dimming layer. The rest of the structure, parameters, materials and preparation method are the same as those in Example 1.

[0158] This application uses b1 to b9 and a1 to a4 to prepare the dimming device electrodes. To prevent short circuits between the upper and lower electrode layers, all device edges were passivated. All devices underwent high temperature and high humidity tests and peel strength tests. The high temperature and high humidity conditions were 70°C, 100% humidity, and drying for 6 hours. The peel strength test was conducted on an electronic tensile testing machine, and the transmittance dynamic range was determined using a voltage-transmittance testing device. The results are shown in Table 1 (NA in the table indicates below the detection limit).

[0159] Table 1

[0160] As can be seen from Table 1, the device uniformity of Example 3 is reduced compared to Example 1 and Example 2. This is mainly because the first sealing frame 201 of Example 3 does not have supporting particles 103. Since the first sealing frame 201 is located between the receiving cavity and the second sealing frame 202, it forms a structure in which the supporting force in the middle is lower than the supporting force on both sides, which leads to a decrease in the uniformity of the device in the peel force test.

[0161] Comparing Examples 1, 4, and 5, it can be seen that, compared to Examples 1 where both the first sealing frame 201 and the second sealing frame 202 are made of the same material, in Example 1, the first sealing frame 201 can block the diffusion of small molecules of the dimming material 104, and the second sealing frame 202 firmly adheres the first conductive film 102 and the second conductive film 106, effectively improving device performance. Table 1 shows that Examples 1 and 6 have better device performance. However, it is easy to see from Figures 10 and 11 that, under certain pressure, Example 6, through the fixing coating 107, can alleviate the movement of the support particles 103, while in Example 1, the friction between the support particles 103 and the conductive film is smaller, making them easier to move under pressure, resulting in poorer uniformity of the device after a certain pressure. Compared to Examples 6 and 9, where both sides of the support particles 103 are fixed with the fixing coating 107, Examples 7 and 8 only fix one side of the support particles 103. When pressure is applied in different directions, devices with a single-sided fixing structure are prone to movement of the support particles 103. As shown in Table 1, the devices in Examples 10-12 exhibit good support performance and high adhesion between the first conductive film 102 and the second conductive film 106. Furthermore, they effectively block the diffusion of small organic molecules in the dimming material 104, preventing adhesive failure and maintaining high uniformity. The applicant declares that the above descriptions are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Those skilled in the art should understand that any variations or substitutions easily conceived by those skilled in the art within the technical scope disclosed in this application fall within the scope of protection and disclosure of this application.

Claims

1. A suspended particle dimming device, comprising a first conductive base layer, a dimming layer and a second conductive base layer stacked sequentially, the dimming layer comprising at least two nested frame bodies, a receiving cavity being formed between the first conductive base layer, the second conductive base layer and the inner frame body, the receiving cavity being filled with dimming material, and a plurality of uniformly distributed support particles being disposed inside at least one frame body.

2. The suspended particle dimming device according to claim 1, wherein, The at least two-layer sealing frame body includes a first sealing frame body and at least one second sealing frame body sleeved outside the first sealing frame body. The receiving cavity is formed between the first sealing frame body, the first conductive base layer and the second conductive base layer. The supporting particles are disposed inside at least the first sealing frame body.

3. The suspended particle dimming device according to claim 2, wherein, The material of the first sealing frame includes any one or a combination of at least two of the following: UV-curable silicone adhesive, thermosetting silicone adhesive, moisture-curing silicone adhesive, and UV-heated mixed silicone adhesive. The material of the second sealing frame includes any one or a combination of at least two of epoxy resin thermosetting adhesives, acrylic light-curing adhesives, or UV-heated mixed adhesives.

4. The suspended particle dimming device according to any one of claims 1-3, wherein, The supporting particles are also evenly distributed within the cavity.

5. The suspended particle dimming device according to any one of claims 1-4, wherein, The distribution density of the supporting particles is 1–100 particles / mm². 2 ; Preferably, the material of the supporting particles includes any one or a combination of at least two of the following: polymer resin, glass fiber, or inorganic materials. Preferably, the shape of the supporting particle includes any one or a combination of at least two of the following: spherical, cylindrical, or cuboid. Preferably, the diameter of the supporting particles is 2–100 μm; Preferably, the color of the supporting particles includes any one or a combination of at least two of the following: colorless, gray, red, green, white, or black.

6. The suspended particle dimming device according to any one of claims 1-5, wherein, The dimming layer is a flexible dimming layer, and the dimming material is a liquid material and / or a gel material.

7. The suspended particle dimming device according to any one of claims 1-6, wherein, The dimming material includes any one or a combination of at least two of the following: SDP suspension, SPD suspension gel, liquid crystal composition, or electrochromic gel.

8. The suspended particle dimming device according to any one of claims 1-7, wherein, At least one fixing coating layer is further provided between the first conductive substrate and the dimming layer, and / or between the second conductive substrate and the dimming layer; Preferably, the thickness of the fixing coating is 0.005–30 μm; Preferably, the fixing coating comprises any one or a combination of at least two of silicone, acrylic resin, polyurethane resin or epoxy resin.

9. The suspended particle dimming device according to any one of claims 1-8, wherein, The first conductive base layer includes a first substrate, and a first conductive film is disposed on the surface of the first substrate near the dimming layer; the second conductive base layer includes a second substrate, and a second conductive film is disposed on the surface of the second substrate near the dimming layer. Preferably, the thickness of the first conductive film and the second conductive film are each independently 50-500 μm, and more preferably 125-250 μm; Preferably, the first substrate and the second substrate are independently transparent substrates; Preferably, the first conductive film and the second conductive film each independently comprise any one or a combination of at least two of the following: carbon-based conductive film, metal nanowire conductive film, or metal oxide film.

10. A method for preparing a suspended particle dimming device according to any one of claims 1-9, comprising: After wet spraying of supporting particles onto the surface of the first conductive substrate and / or the second conductive substrate, and fabricating at least two layers of sealing body, a dimming material is filled to form a dimming layer, and the sealing body is cured to obtain a suspended particle dimming device.

11. The preparation method according to claim 10, wherein, The wet spraying process includes: mixing the support particles with a solvent and adding the mixture into the feeding chamber of the powder spraying device, and then spraying it onto the surface of the first conductive substrate or the second conductive substrate by means of circulating feeding. Preferably, the method of manufacturing the sealing frame body includes: using adhesive material to sequentially form at least two layers of sealing frame body on the surface of a first conductive base layer or a second conductive base layer coated with supporting particles, and then performing a curing treatment.

12. The preparation method according to claim 10 or 11, wherein, The supporting particles include any one or a combination of at least two of the following: polymer resin, glass fiber, or inorganic materials. Preferably, the solvent includes any one or a combination of at least two of water, ethanol, isopropanol, acetone, N-methylpyrrolidone, ethyl acetate, or propylene glycol methyl ether acetate; Preferably, the dimming material is filled using a vacuum injection method or a drop-in vacuum bonding method.

13. The preparation method according to any one of claims 10-12, wherein, The preparation method further includes: before the wet spraying, applying a primer to the surface of the first conductive substrate and / or the second conductive substrate, and then drying it to form a fixed coating.

14. An application of the suspended particle dimming device according to any one of claims 1-9, wherein, The aforementioned suspended particle dimming device is used for flat or curved glass.

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