A light control film wiring structure and light control glass

Abstract

The utility model relates to a light adjusting film technical field especially, relates to a light adjusting film wiring structure and light adjusting glass. The light adjusting film wiring structure ITO electrode layer, connecting layer and connector, the connecting layer includes silver paste layer, conductive cloth and flexible circuit board who are sequentially laminated and set in the ITO electrode layer surface, the lower surface of conductive cloth is pasted with silver paste layer through conductive pressure -sensitive adhesive, and the upper surface is pasted with flexible circuit board through conductive pressure -sensitive adhesive, the flexible circuit board is equipped with the gold finger of the extension connecting layer and the connector plug -in cooperation. The utility model provides the scheme, replaces traditional copper foil or ACF hot pressing glue through conductive cloth, realizes normal temperature and normal pressure pasting, can avoid hot pressing / welding to the damage of film material, simplifies the process and reduces the cost, has the advantage of improving the stability and the adaptability of light adjusting film wiring structure.

Description

Technical Field

[0001] This utility model relates to the field of dimming film technology, and in particular to a dimming film wiring structure and dimming glass. Background Technology

[0002] As a core functional component of smart glass, the reliability and feasibility of the wiring structure of the dimming film directly determine the mass production efficiency and application scenarios of the product. In existing technologies, the connection between the dimming film and external circuits mainly includes copper foil power extraction and ACF hot-pressing connection technology. The copper foil power extraction process achieves current conduction by sequentially stacking copper foil with conductive adhesive, silver paste, and ITO electrode layers. Although this method is low-cost, it has significant structural defects. The high temperatures generated during welding degrade the performance of the conductive adhesive, significantly reducing adhesion, and the raised structure formed by the solder joints and leads easily causes mechanical damage to the film material. More seriously, the thermal expansion effect of the solder joints and vibrations during transportation can cause delamination between the copper foil and the ITO layer, resulting in a persistently high electrode damage rate.

[0003] While ACF hot-press bonding technology offers high connection strength, its implementation faces numerous limitations. The high-temperature, high-pressure process poses a serious threat to the brittle ITO electrode layer; microcracks generated when conductive particles pierce the electrodes can disrupt the integrity of the conductive pathway. The process also suffers from high equipment investment and low hot-pressing efficiency. The limited area of ​​a single hot-press cycle necessitates hundreds of hot-pressing cycles for large-size dimming films, significantly increasing labor costs. Furthermore, the specialized ACF adhesive material requires strict low-temperature storage conditions, and its short shelf life and high price also substantially increase overall production costs.

[0004] Neither of the aforementioned technical solutions effectively resolves the contradiction between conductivity reliability and process economy. They either sacrifice stability for low cost or pursue connection strength at a high cost, a dilemma that severely restricts the large-scale application of dimming film products. Particularly in the field of large-size dimming glass for architectural applications, existing wiring technologies cannot meet long-term reliability requirements while also struggling to control reasonable manufacturing costs.

[0005] To address the aforementioned issues, existing technologies urgently need improvement. Utility Model Content

[0006] To overcome the problems existing in related technologies, this utility model provides a dimming film wiring structure. By replacing traditional copper foil or ACF hot-press adhesive with conductive cloth, it achieves room temperature and pressure bonding, which can avoid damage to the film material caused by hot pressing / welding, simplify the process and reduce costs. It also has the advantages of improving the stability and adaptability of the dimming film wiring structure.

[0007] This utility model provides a dimming film wiring structure, including an ITO electrode layer, a connecting layer, and a connector. The connecting layer includes a silver paste layer, a conductive cloth, and a flexible circuit board stacked sequentially on the surface of the ITO electrode layer. The lower surface of the conductive cloth is bonded to the silver paste layer by a voltage-sensitive adhesive, and the upper surface is bonded to the flexible circuit board by a voltage-sensitive adhesive. The flexible circuit board is provided with gold fingers that extend out of the connecting layer and engage with the connector.

[0008] In some embodiments, the conductive cloth includes a polyester fiber base layer, wherein nickel particles are adsorbed by chemical precipitation or metal physical transfer, and a copper layer and a nickel layer are sequentially electroplated on the outer surface of the nickel particles, and an antioxidant layer is formed on the surface of the nickel layer by chemical precipitation.

[0009] In some embodiments, the polyester fiber base layer has a thickness of 18-50 μm, a surface resistivity of 0.05-0.1 Ω, and a vertical resistivity of 0.035-0.05 Ω; the copper layer has a thickness of 1-2 μm, the nickel layer has a thickness of 1-2 μm, and the antioxidant layer is a nickel oxide passivation film.

[0010] In some embodiments, the voltage-sensitive adhesive is a polyolefin voltage-sensitive adhesive, and the initial adhesion force of the voltage-sensitive adhesive is ≥6.6 N / cm.

[0011] In some embodiments, the conductive voltage-sensitive adhesive is divided into two outer layers and an intermediate layer sandwiched between the two outer layers along the thickness direction; both the outer layer and the intermediate layer include a resin matrix and a conductive material filled in the resin matrix;

[0012] The outer conductive material comprises flake silver powder and first conductive particles, and the middle conductive material comprises second conductive particles; the mass percentage of the first conductive particles is the same as the mass percentage of the second conductive particles.

[0013] In some embodiments, the resin matrix of both the outer layer and the intermediate layer is acrylic resin.

[0014] In some embodiments, the surface resistance of the intermediate layer in the XY direction is 0.18-0.22Ω, and the initial contact resistance in the Z direction is 0.045-0.055Ω; the surface resistance of the outer layer in the XY direction is 0.14-0.18Ω, and the initial contact resistance in the Z direction is 0.03-0.045Ω.

[0015] In some embodiments, the outer layer has a thickness of 10-20 μm, and the middle layer has a thickness of 20-50 μm.

[0016] This utility model also provides a dimming glass, including the dimming film wiring structure described above.

[0017] The following are the beneficial effects of implementing this utility model:

[0018] (1) The conductive cloth is used instead of copper foil or ACF hot-press adhesive. The conductive voltage-sensitive adhesive on both sides of the conductive cloth has temperature and pressure bonding characteristics. Without heating or pressurization, the flexible circuit board and ITO electrode layer can be stably connected by manual bonding, avoiding the brittle damage to the ITO layer caused by traditional hot pressing or welding high temperature, solving the problem of secondary damage, and effectively improving the quality level of the product.

[0019] (2) The flexible circuit board and conductive cloth are integrated into a thin and flat structure, and the gold fingers are connected to the external wires through the connector. This avoids the problems of solder joint protrusion and wire entanglement caused by welding in the traditional copper foil solution, reduces the squeezing and scratching of the film material, and is suitable for the winding and transportation of large-area dimming film for building.

[0020] (3) By using the low-resistance contact of the outer layer of the conductive voltage-sensitive adhesive and the gradient design of the middle layer, the interface resistance between the conductive voltage-sensitive adhesive and the silver paste and FPC can be precisely controlled, solving the technical pain point of resistance change caused by the fluctuation of contact area in traditional conductive adhesives. Attached Figure Description

[0021] The above and other objects, features and advantages of the present invention will become more apparent from the accompanying drawings, in which like reference numerals generally represent like parts.

[0022] Figure 1 This is an exploded view of the dimming film wiring structure shown in an embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram of the wiring structure of the dimming film shown in an embodiment of the present invention;

[0024] Figure 3 This is a schematic diagram of the structure of the conductive voltage-sensitive adhesive shown in an embodiment of this utility model.

[0025] Figure label:

[0026] 1. ITO electrode layer; 2. Silver paste layer; 3. Conductive cloth; 4. Conductive voltage-sensitive adhesive; 40. Outer layer; 41. Intermediate layer; 5. Flexible circuit board; 50. Gold fingers. Detailed Implementation

[0027] Preferred embodiments of the present invention will now be described in more detail with reference to the accompanying drawings. While preferred embodiments of the present invention are shown in the drawings, it should be understood that the present invention may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present invention will be thorough and complete, and will fully convey the scope of the present invention to those skilled in the art.

[0028] The terminology used in this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular forms “a,” “the,” and “the” used in this invention and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0029] It should be understood that although the terms "first," "second," "third," etc., may be used in this invention to describe various information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this invention, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Thus, features defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0030] Large-area dimming films for buildings (such as 2m×3m curtain wall glass films and 1.5m×2m partition films) and curved dimming films for vehicles (such as dashboard curved areas and sunroof shading films) have extremely high requirements for the reliability of the wiring structure and the stability of the process. Traditional copper foil power supply solutions use conductive adhesive copper foil bonded to a silver paste layer 2, but the high temperature of welding causes the adhesive layer to fail, and the stress at the solder joints causes wrinkles and damage to the film material. The ACF hot-pressing solution relies on a high-temperature and high-pressure bonding process, which is prone to causing micro-cracks in the ITO layer, and the hot-pressing equipment is expensive and the process efficiency is low. Both solutions have the drawback of being difficult to balance conductivity stability and process compatibility. Once the above-mentioned defects lead to the failure of the wiring structure (such as open circuits or excessive contact resistance), the dimming film will be unable to dim locally or entirely, resulting in the dimming film being directly judged as a defective product, which increases the company's material costs.

[0031] To address the aforementioned issues, this utility model provides a dimming film wiring structure that replaces traditional copper foil or ACF hot-press adhesive with conductive cloth, achieving room temperature and pressure bonding. This avoids damage to the film material caused by hot pressing / welding, simplifies the process, reduces costs, and improves the stability and adaptability of the dimming film wiring structure.

[0032] The technical solutions of the embodiments of this utility model are described in detail below with reference to the accompanying drawings.

[0033] Example 1

[0034] This utility model proposes a wiring structure for a dimming film, such as... Figures 1 to 2 As shown, it includes an ITO electrode layer 1, a connecting layer, and a connector. The connecting layer includes a silver paste layer 2, a conductive cloth 3, and a flexible circuit board 5, which are sequentially stacked on the surface of the ITO electrode layer 1. The lower surface of the conductive cloth 3 is bonded to the silver paste layer 2 through a conductive voltage-sensitive adhesive 4, and the upper surface is bonded to the flexible circuit board 5 through a conductive voltage-sensitive adhesive 4. The flexible circuit board 5 is provided with gold fingers 50 that extend out of the connecting layer and are inserted into the connector.

[0035] Specifically, the silver paste layer 2 is screen-printed onto the surface of the ITO electrode to conduct electricity between the ITO electrode layer 1 and the flexible printed circuit board 5 (FPC). The conductive cloth 3 forms a fully bonded interface with the silver paste layer 2 and the flexible printed circuit board 5 through conductive voltage-sensitive adhesive 4 on both its upper and lower surfaces. The fiber structure of the conductive cloth 3 undergoes elastic deformation under pressure, dispersing external mechanical stress. The gold fingers 50 of the flexible printed circuit board 5 extend beyond the connecting layer, forming a detachable connection with the connector through physical insertion. At room temperature, the materials of each layer are tightly bonded by the viscoelastic properties of the conductive voltage-sensitive adhesive 4. Conductive particles form a three-dimensional conductive path within the adhesive layer, ensuring current conduction in the vertical direction. This structure achieves electrical interconnection through a non-welding, non-thermo-pressing manual bonding method, eliminating the risk of damage to the ITO electrode caused by high-temperature and high-pressure processes.

[0036] It should be noted that the flexible circuit board 5 of this utility model is a single-sided board, and its structure can be divided into two areas. One area is the gold finger area, and the other area is the connection layer composite area. Compared with the flexible circuit boards of the prior art, the connection layer composite area eliminates the adhesive layer and cover film that are laminated on the copper foil layer.

[0037] Furthermore, the conductive cloth 3 includes a polyester fiber base layer, which adsorbs nickel particles through chemical precipitation or metal physical transfer. A copper layer and a nickel layer are sequentially electroplated on the outer surface of the nickel particles, and an antioxidant layer is formed on the surface of the nickel layer through chemical precipitation.

[0038] Specifically, the polyester fiber base layer serves as a flexible support structure, fixing nickel particles through chemical bonding to avoid interfacial delamination caused by traditional mechanical bonding. Copper layers deposited sequentially on the surface of the nickel particles form a gradient conductive structure with the nickel layer; the copper layer reduces overall resistance, while the nickel layer inhibits copper oxidation diffusion. An outer 40 passivation film further blocks environmental corrosion, forming a multi-layered protective system. The materials in each layer are metallurgically bonded to form a stable interface, maintaining conductive continuity during dynamic bending.

[0039] To further verify the technical advantages of this utility model in using conductive cloth 3 to replace traditional copper foil, the key performance parameters of the 35μm nickel-copper plated conductive cloth 3 and the 35μm rolled copper foil commonly used in dimming films are compared below.

[0040] Bending performance, abrasion resistance, and failure tests were conducted on the copper foil and conductive cloth 3. In a 180° reciprocating bending test with a bending radius of 5mm, the copper foil's reciprocating bending life was in the range of 2500-3000 cycles, while the nickel-plated conductive cloth 3 reached 100,000 cycles. This shows that the bending life of the conductive cloth 3 is more than 30 times that of the copper foil. The polyester fiber base layer, with its flexible support, can effectively disperse bending stress, preventing premature fracture of the copper foil due to lattice fatigue, and thus preventing wrinkles caused by external forces during material transfer. In an abrasion resistance test with a 500g load, using a CS-10 grinding wheel at a speed of 50rpm, the copper foil withstood 200-250 abrasion cycles, while the nickel-copper plated conductive cloth 3 withstood greater than or equal to 5000 cycles. This shows that the abrasion resistance of the conductive cloth 3 is more than 20 times that of the copper foil, and it can withstand long-term friction without falling off. In failure tests, bending causes the copper foil lattice to crack, and friction causes mechanical damage to the copper foil surface, causing its contact resistance to rise instantaneously to over 100Ω. The nickel-copper plated conductive cloth 3 exhibits a slow increase in resistance due to fiber fatigue (resistance increase less than or equal to 20% after 50,000 bends), but there is no risk of sudden open circuit. It is evident that copper foil failure manifests as catastrophic fracture with no warning; while the failure of the nickel-copper plated conductive cloth 3 is characterized by predictable resistance drift, which can meet the long-term use requirements of dimming films for over 10 years, helping to reduce maintenance costs.

[0041] Furthermore, the total thickness of the conductive cloth 3 is 18-50 μm, the surface resistance is 0.05-0.1 Ω, and the vertical resistance is 0.035-0.05 Ω; the copper layer thickness is 1-2 μm, the nickel layer thickness is 1-2 μm, and the anti-oxidation layer is a nickel oxide passivation film.

[0042] Specifically, the thickness of the polyester fiber base layer is set within the range of 18-50 μm, ensuring that the base layer possesses sufficient flexibility to adapt to bending deformation while providing the necessary mechanical strength to resist thermal expansion stress. The surface resistivity is controlled within the range of 0.05-0.1 ohms to ensure uniform current distribution in the in-plane direction, thereby preventing hotspot effects and material degradation caused by uneven resistance. The vertical resistivity is limited to the range of 0.035 to 0.05 ohms, optimizing interlayer conductivity and ensuring stable current transmission in the thickness direction. The copper layer thickness is maintained within the range of 1-2 μm; based on the characteristics of the electroplating process, this thickness can efficiently conduct current while avoiding the decrease in adhesion and increased cost caused by excessive thickness. The nickel layer thickness is set within the range of 1-2 μm, forming a dense protective layer to prevent copper oxidation and provide a reliable soldering surface. The anti-oxidation layer adopts a nickel oxide passivation film structure, forming a stable oxide layer through a chemical precipitation process, effectively isolating environmental factors and maintaining long-term conductivity stability. These rationally set parameters collectively improve the reliability and process adaptability of the wiring structure, fundamentally suppressing delamination.

[0043] Polyester fiber substrate serves as the supporting carrier, forming a composite conductive structure through surface metallization. A copper layer acts as the primary conductive medium, creating a continuous conductive path laterally, while a nickel layer acts as a transition layer, protecting the copper layer and enhancing interlayer bonding. A nickel oxide passivation film, generated through a chemical conversion reaction, covers the micropores on the nickel layer surface. In high-temperature, high-pressure processes, the conductive cloth 3 balances mechanical strength and elastic deformation capacity through controlled total thickness. The synergistic optimization of surface and vertical resistance ensures stable current conduction under complex stress, and the matching design of the metal plating thickness avoids interlayer delamination caused by differences in thermal expansion coefficients.

[0044] Furthermore, the voltage-sensitive adhesive 4 is a polyolefin voltage-sensitive adhesive 4, and the initial adhesion force of the voltage-sensitive adhesive 4 is ≥6.6N / cm.

[0045] Specifically, the flexibility of the polyolefin matrix allows it to absorb the difference in thermal expansion between the dimming film and the connecting layer, inhibiting the embrittlement and cracking of the adhesive layer. The initial adhesion setting allows the adhesive layer to form a stable bond without additional pressure after bonding, avoiding interface slippage or local debonding caused by insufficient adhesion of traditional conductive adhesives.

[0046] In this embodiment, conductive cloth 3 is used instead of copper foil or ACF hot-press adhesive. The conductive voltage-sensitive adhesive 4 on both sides of the conductive cloth 3 has temperature and pressure bonding characteristics. Without heating or pressurization, the flexible circuit board 5 and the ITO electrode layer can be stably connected by manual bonding. This can avoid the brittle damage to the ITO layer caused by the high temperature of traditional hot pressing or welding, solve the problem of secondary damage, and effectively improve the quality level of the product.

[0047] Example 2

[0048] In the wiring structure of dimming films, the conductivity stability of the connecting layer is a core indicator determining the optical uniformity of the product. Although Example 1 solves the mechanical damage and puncture defects of the ITO electrode layer 1 caused by traditional technical solutions (such as copper foil power extraction and FPC-ACF hot pressing), the manual bonding process adopted in this invention still introduces new technical bottlenecks. Specifically, manual bonding relies on personal experience, and even with the assistance of rollers, the uniformity of the contact interface between the conductive voltage-sensitive adhesive 4 and the silver paste layer 2 and flexible circuit board 5 cannot be guaranteed after each bonding, resulting in a certain difference in the resistance value of each dimming film. Actual measurement data shows that the contact resistance fluctuation range of the conductive voltage-sensitive adhesive 4 after manual bonding can reach 0.02-0.1Ω. While resistance fluctuations have a relatively small impact on small-area dimming films, they have a significant effect on large-area dimming glass (e.g., 2m x 3m) building curtain walls. Because large-area dimming films require multiple wiring structures, the resistance differences between areas are further amplified, leading to uneven current distribution across the entire dimming film. This results in inconsistent deflection angles of liquid crystal molecules, ultimately forming bright and dark stripes on the surface of the dimming film. Especially in transparent mode, the stripe contrast can reach 5%–8%, a contrast clearly visible to the naked eye, affecting the overall aesthetics of the building curtain wall.

[0049] To address the aforementioned issues, this embodiment 2 proposes a gradient conductive structure for the voltage-sensitive adhesive 4 along its thickness direction, such as... Figure 3 As shown, the conductive voltage-sensitive adhesive 4 is divided into two outer layers 40 and an intermediate layer 41 sandwiched between the two outer layers 40 along the thickness direction; both the outer layer 40 and the intermediate layer 41 include a resin matrix and a conductive material filled in the resin matrix. The conductive material of the outer layer 40 includes flake silver powder and first conductive particles, and the conductive material of the intermediate layer 41 includes second conductive particles; the mass percentage of the first conductive particles in the outer layer 40 is the same as the mass percentage of the second conductive particles in the intermediate layer 41.

[0050] Specifically, the outer layer 40 is filled with a composite of flake silver powder and conductive particles. The flake silver powder provides a horizontal conductive network, while the conductive particles fill the gaps between the flake silver powder, improving conductivity continuity and thus forming a dense conductive network at the interface, ensuring low contact resistance with the silver paste layer 2 and the flexible circuit board 5. The resin matrix, as a continuous phase, encapsulates the conductive material, and the flexibility of the polymer chains buffers external mechanical stress. The gradient distribution of conductive materials between the outer layer 40 and the intermediate layer 41 creates a difference in conductivity in the thickness direction of the adhesive layer. The high conductivity of the outer layer 40 preferentially reduces the interfacial contact resistance, and the intermediate layer 41 regulates the overall resistance of the voltage-sensitive adhesive 4.

[0051] It should be noted that in extreme cases (such as the presence of bubbles or foreign matter >50μm between the conductive voltage-sensitive adhesive 4 and the silver paste layer 2), local contact resistance may still be abnormally increased (>0.6Ω). In this case, it is necessary to screen through online resistance detection process (such as infrared thermal imaging). Moreover, this type of defect cannot be solved by this utility model.

[0052] In one specific embodiment, the content of flake silver powder can be set to 5% to 10% of the total mass of the outer layer 40 conductive voltage-sensitive adhesive 4, while the proportion of conductive material in the outer layer 40 conductive voltage-sensitive adhesive 4 can be set in the range of 45% to 55%, and the proportion of conductive material in the intermediate layer 41 can be set in the range of 35% to 45%. The resin matrix of the outer layer 40 can be acrylic resin, and the intermediate layer 41 can be the same resin matrix as the outer layer 40 or epoxy resin. A typical adhesive composition of the outer conductive voltage-sensitive adhesive 4 can be formulated as follows: 35% acrylic resin matrix, 7.5% flake silver powder with an average particle size of 5μm, 45% nickel-plated graphite particles with a particle size of 1μm, 8% tackifying resin (terpene phenolic resin), 2% antioxidant, 1% dispersant, 0.5% defoamer, and 1% wetting agent.

[0053] To facilitate understanding of the gradient conductive structure of the voltage-sensitive adhesive 4 of this invention, the preparation process of the gradient conductive structure of the voltage-sensitive adhesive 4 is described below.

[0054] 1) Select a PET release film with a thickness of 50-75μm, a peel force of 3-5g / in, and a surface tension of ≥38mN / m. Remove oil and impurities from the surface of the release paper, optimize the surface tension, and ensure that the conductive voltage-sensitive adhesive 4 coating adheres evenly and is easy to peel off later.

[0055] 2) Take conductive adhesive with a high proportion of conductive materials (flake silver powder and first conductive particles) and conductive adhesive with a low proportion of conductive particles.

[0056] 3) Using a high proportion of conductive material, the first outer layer of 40 conductive voltage-sensitive adhesive 4 water is printed on the PET release film by screen printing. After it is finger-dried (the adhesive layer does not transfer when touched), the middle layer of 41 conductive voltage-sensitive adhesive 4 water is printed using conductive adhesive with a low proportion of conductive particles. After the middle layer of 41 conductive voltage-sensitive adhesive 4 water is finger-dried, the second outer layer of 40 conductive voltage-sensitive adhesive 4 water is printed on the PET release film by screen printing using a high proportion of conductive material.

[0057] Furthermore, the conductive particles include at least one of gold, silver, copper, aluminum, zinc, iron, nickel, and nickel-plated graphite particles.

[0058] Specifically, the conductive particle system achieves functional complementarity through the combination of multiple materials. Noble metal particles are used in scenarios requiring low resistance, such as silver particles forming a high-conductivity region at the contact interface; ordinary metal particles are configured in non-critical areas to reduce material costs, such as aluminum particles dispersed in the auxiliary conductive layer; nickel particles are placed in easily oxidized locations to suppress electrochemical corrosion, such as preferential distribution in humidity-sensitive areas; nickel-plated graphite particles are applied to connection parts where mechanical stress exists, such as absorbing deformation stress through the graphite substrate in the bending area of ​​the flexible circuit board.

[0059] Furthermore, the resin matrix of both the outer layer 40 and the intermediate layer 41 is acrylic resin.

[0060] Specifically, the outer layer 40 and the middle layer 41 of the conductive voltage-sensitive adhesive 4 use the same resin matrix, allowing the molecular chains between the two layers to form a continuous phase structure through mutual dissolution. Under high-temperature processing conditions, the thermal expansion coefficients of the acrylic resins are consistent, avoiding shear stress caused by uneven heating between layers. When conductive particles migrate in the resin matrix, there is no resistance barrier formed by abrupt material changes at the interface, and the conductive path remains continuous in the thickness direction. When the dimming film is bent or vibrated, each layer of the conductive voltage-sensitive adhesive 4 deforms synchronously due to its consistent mechanical properties, avoiding local peeling that could lead to conductive failure.

[0061] Furthermore, the surface resistivity of the intermediate layer 41 in the XY direction is 0.18-0.22Ω, and the initial contact resistance in the Z direction is 0.045-0.055Ω; the surface resistivity of the outer layer 40 in the XY direction is 0.14-0.18Ω, and the initial contact resistance in the Z direction is 0.03-0.045Ω; the thickness of the outer layer is 10-20μm, and the thickness of the intermediate layer is 20-50μm.

[0062] In this embodiment, the low-resistance contact design of the outer layer 40 and the adjustable resistance of the middle layer 41 work synergistically to achieve precise control of conductivity. The outer layer 40 reduces interfacial contact resistance through a composite material design and employs a composite filling system of flake silver powder and conductive particles. The flake silver powder forms a continuous horizontal conductive network through surface contact, while the conductive particles fill the gaps between the silver powder and construct vertical conductive paths. This controls the interfacial contact resistance between the outer layer 40 and the silver paste layer 2 / flexible circuit board 5 to be between 0.03 and 0.045 Ω. Compared to traditional uniform conductive adhesives, this structure reduces interfacial contact resistance by more than 40%, effectively suppressing resistance fluctuations caused by tiny (<10 μm) air bubbles and misalignments at the interface during manual bonding. The intermediate layer 41 dynamically adjusts its overall resistance through the proportion of conductive materials. Containing only conductive particles, the resistance of the intermediate layer 41 can be adjusted as needed by changing the type of conductive particles (e.g., replacing silver particles with nickel-plated graphite particles can increase resistance) or the filling amount (e.g., reducing the filling amount by 5% can increase the Z-direction contact resistance from 0.045Ω to 0.06Ω). Therefore, in practical applications, the resistance of the intermediate layer 41 needs to be flexibly set according to the area, driving voltage, and power consumption requirements of the dimming film (e.g., a 0.055Ω intermediate layer 41 can be used for a large-area dimming film of 2m×3m, and a 0.045Ω intermediate layer 41 can be used for a small-size automotive film). The surface resistance in the XY directions and the contact resistance in the Z direction of the outer layer 40 are always lower than those of the intermediate layer 41, ensuring that current preferentially passes through the low-resistance interface of the outer layer 40, and then the intermediate layer 41 regulates the overall conduction efficiency.

[0063] Through the above technical solution, by designing the resistance gradient between the outer layer 40 and the middle layer 41, the low interface resistance is achieved by utilizing the gradient distribution of conductive materials. This solves the problem of conductivity uniformity caused by manual bonding from a material perspective. When the interface contact resistance of the dimming film fluctuates due to changes in ambient temperature (-40 to 85℃) or mechanical deformation (bending radius ≥ 5mm), the middle layer 41 can reduce the total resistance fluctuation range through dynamic compensation of its own resistance (such as the decrease in resistance of the middle layer 41 when the temperature rises, which offsets the increase in contact resistance of the outer layer 40). This provides key technical support for the optical stability of large-area dimming glass.

[0064] The manufacturing process of the dimming film wiring structure is as follows:

[0065] 1) Use a hook knife to cut the edge of the dimming film in half, and use a lint-free paper dipped in anhydrous ethanol to wipe the surface of the lower ITO layer to remove residual liquid crystal;

[0066] 2) Use a 300-mesh stainless steel screen to screen print silver paste at a scraper pressure of 0.2MPa and a speed of 50mm / s, and then dry with hot air;

[0067] 3) The 15μm conductive voltage-sensitive adhesive 4 is rolled and laminated on both sides of the 35μm conductive cloth 3 to form a conductive cloth 3 double-sided adhesive with a total thickness of 65μm. Then, the conductive film with the same shape as the flexible circuit board 5 is produced by die cutting.

[0068] 4) Peel off the release film under the double-sided adhesive of the conductive cloth 3, align the silver paste layer 2 manually using the positioning marks, and then press it together at room temperature with a rubber roller. Next, peel off the upper release film, align and attach the gold-plated contacts of the flexible circuit board 5, and repeat the pressing steps to ensure that there are no air bubbles at the interface;

[0069] 5) Insert the gold finger 50 into the connector to complete the wiring.

[0070] This invention also proposes a dimming glass, including a dimming film wiring structure. The dimming film wiring structure includes an ITO electrode layer 1, a connecting layer, and a connector. The connecting layer includes a silver paste layer 2, a conductive cloth 3, and a flexible circuit board 5, which are sequentially stacked on the surface of the ITO electrode layer 1. The lower surface of the conductive cloth 3 is bonded to the silver paste layer 2 via a conductive voltage-sensitive adhesive 4, and the upper surface is bonded to the flexible circuit board 5 via the conductive voltage-sensitive adhesive 4. The flexible circuit board 5 is provided with gold fingers 50 that extend out of the connecting layer and engage with the connector. The connector refers to a standardized electronic connector, specifically a board-to-board connector or a ZIF connector, used to achieve a quick plug-in connection between the flexible circuit board 5 and an external control circuit.

[0071] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A dimming film wiring structure, characterized in that, The device includes an ITO electrode layer, a connecting layer, and a connector. The connecting layer includes a silver paste layer, a conductive cloth, and a flexible circuit board, which are sequentially stacked on the surface of the ITO electrode layer. The lower surface of the conductive cloth is bonded to the silver paste layer by a voltage-sensitive adhesive, and the upper surface is bonded to the flexible circuit board by a voltage-sensitive adhesive. The flexible circuit board is provided with gold fingers that extend out of the connecting layer and are inserted into the connector.

2. The dimming film wiring structure according to claim 1, characterized in that, The conductive cloth includes a polyester fiber base layer, which adsorbs nickel particles through chemical precipitation or metal physical transfer. A copper layer and a nickel layer are sequentially electroplated on the outer surface of the nickel particles, and an antioxidant layer is formed on the surface of the nickel layer through chemical precipitation.

3. The dimming film wiring structure according to claim 2, characterized in that, The polyester fiber base layer has a thickness of 18-50 μm, a surface resistivity of 0.05-0.1 Ω, and a vertical resistivity of 0.035-0.05 Ω; the copper layer has a thickness of 1-2 μm, the nickel layer has a thickness of 1-2 μm, and the antioxidant layer is a nickel oxide passivation film.

4. The dimming film wiring structure according to claim 1, characterized in that, The voltage-sensitive adhesive is a polyolefin voltage-sensitive adhesive, and the initial adhesion force of the voltage-sensitive adhesive is ≥6.6N / cm.

5. The dimming film wiring structure according to claim 4, characterized in that, The conductive voltage-sensitive adhesive is divided into two outer layers and an intermediate layer sandwiched between the two outer layers along the thickness direction; both the outer layer and the intermediate layer include a resin matrix and a conductive material filled in the resin matrix; The outer conductive material comprises flake silver powder and first conductive particles, and the middle conductive material comprises second conductive particles; the mass percentage of the first conductive particles is the same as the mass percentage of the second conductive particles.

6. The dimming film wiring structure according to claim 5, characterized in that, The resin matrix of both the outer and middle layers is acrylic resin.

7. The dimming film wiring structure according to claim 5, characterized in that, The surface resistance of the intermediate layer in the XY direction is 0.18-0.22Ω, and the initial contact resistance in the Z direction is 0.045-0.055Ω; the surface resistance of the outer layer in the XY direction is 0.14-0.18Ω, and the initial contact resistance in the Z direction is 0.03-0.045Ω.

8. The dimming film wiring structure according to claim 7, characterized in that, The outer layer has a thickness of 10-20 μm, and the middle layer has a thickness of 20-50 μm.

9. A type of dimming glass, characterized in that, Includes the dimming film wiring structure as described in any one of claims 1 to 8.

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