Electric heating glass laminate, electric heating glass, and preparation method and application of electric heating glass

Abstract

The invention discloses an electric heating glass laminate, electric heating glass and a preparation method and application thereof, and belongs to the technical field of glass. The electric heating glass laminated body comprises a first inorganic glass plate located on the outer side, a second inorganic glass plate arranged opposite to the first inorganic glass plate, and an electric heating film layer located between the first inorganic glass plate and the second inorganic glass plate. The electrothermal film layer is divided into a plurality of areas, and gaps exist between the areas; and the peripheral edges of the first inorganic glass plate and the second inorganic glass plate and gaps among the areas of the electrothermal film layer are combined in a cold laser welding manner to form an electrothermal glass laminated body. According to the invention, the novel electric heating glass laminated body is designed as the outer side electric heating glass layer, so that the electric heating film layer and the laminated layer in the electric heating glass are independent from each other and are not in contact with each other, the energy-saving effect and the heat transfer efficiency are improved, and the defect that the laminated layer is adjacent to the electric heating film is overcome.

Description

Technical Field

[0001] The present invention relates to an electrothermal glass laminate, electrothermal glass, and a preparation method and application thereof, belonging to the technical field of glass. Background Art

[0002] The window for viewing the outside of the aircraft body from the cockpit of a commercial aircraft is called an aircraft windshield, which is usually divided into a left windshield and a right windshield. The windows extending from the windshield glass to the rear two sides are side windows, also divided into left and right; windshield glass exists not only in commercial aircraft but is also commonly used in various ground vehicles, such as automotive windshield glass. However, the windshield glass on an aircraft is different from that used on the ground in terms of structure, size, and shape, and their respective emphasized functions also have quite significant differences. For example, the primary protection of an aircraft windshield is against bird strikes, while that of an automotive windshield is mainly against stone impacts; another example is that the aircraft windshield needs to have a high-strength heating function in the high-altitude low-temperature environment to prevent ice formation on the outer surface of the glass. Although the windshield glass of ground vehicles also has an electric heating function, there are no such high requirements for the heating power and speed as those of the aircraft windshield. Moreover, the aircraft windshield glass undergoes a temperature difference change from ground temperature to about minus 50 °C at high altitude and a wind pressure change during each aircraft takeoff and landing. Day after day, it experiences thermal and pressure cycles. Therefore, the requirements for the aging resistance test of the aircraft windshield glass, especially for the physical conditions such as temperature, humidity, and wind pressure, are also much higher than those of vehicles traveling on the ground or at sea.

[0003] Since the windshield glass for aviation mainly considers safety factors including ① anti-bird strike, ② anti-scratch (icing particles), and ③ anti-degeneration of the electrothermal adhesive layer (water vapor penetration, thermal and cold cycles), the windshield glass of commercial aircraft usually adopts a three-layer composite glass structure. The outermost layer of glass is relatively thin, and tempered sodium-calcium glass or strengthened aluminosilicate glass with a thickness of about 3 mm can be used. An electrothermal film layer and a conductive circuit are plated on the inner side of the glass as the heating source on the outer side of the windshield glass to prevent ice formation; the outer glass plated with the electrothermal film layer is continuously glued to two pieces of high-strength glass inward, with a thickness of 8 - 10 mm. The three pieces of glass are hot-pressed into one body using a film. The film can be PVB or TPU, etc. The two inner pieces of glass mainly play a role in structural support and providing safety strength. In addition to the basic requirements of safety, anti-collision, and anti-icing, the entire window must meet good visual requirements, and the shape of the glass needs to match the overall curved shape of the aircraft. In particular, it needs to be combined with the aerodynamic design of the aircraft head. Therefore, the aircraft windshield usually presents an irregular curved shape, and certain requirements are imposed on the strength, stress resistance, and deformation resistance of each part.

[0004] When designing the aircraft windshield, when considering the above three main safety factors, if we want to improve the anti-impact ability, we need to use high-strength glass plates. The glass strength can come from the material strength of the glass itself or the external strength improved through physical or chemical tempering; for scratch resistance, we need to improve the surface hardness of the glass or the surface strength improved through glass strengthening; for the third item, to avoid unnecessary driving risks caused by ice formation on the outer surface of the windshield, the key lies in that the heating power should be sufficient and the response time should be short when starting the electric heating device. At the same time, the electric heating device and the control system should be highly reliable, and can effectively prevent water vapor from gradually penetrating into the electric heating layer through the gaps in the adhesive layer due to the harsh climate and wind pressure during flight, ultimately leading to the deterioration of the heating layer or the oxidation of the conductive circuit.

[0005] In the sandwich structure of the aircraft windshield, the inner side of the glass plate in contact with the atmospheric environment on the outside is coated with an electrothermal material, usually a transparent conductive metal oxide, such as In 2 O 3 :Sn (ITO), SnO 2 :F (FTO), ZnO:Al (AZO), graphene thin films, etc. are all well-developed transparent conductive materials. On the premise of ensuring the overall optical clarity of the windshield, controlling the composition, crystal form and thickness of the above transparent conductive film can adjust the surface resistance of the film layer in each area. When externally powered, it can provide sufficient heat for the windshield to prevent ice formation or fogging on the glass surface, ensuring a good view from the cockpit to the outside. In traditional designs, this transparent conductive film is set between the outer glass plate in contact with the external environment and the middle glass plate, and adhered to the adhesive layer. Whether the adhesive layer uses PVB or TPU, during years of aircraft takeoffs and landings and high-altitude flights day after day, the adhesive layer is easily affected by environmental factors such as water vapor penetration in the air and irradiation by high-altitude radiation, and gradually deteriorates. In addition, the toughness of the organic adhesive layer will weaken with the decrease in temperature, that is, the organic adhesive layer will become brittle at too low environmental temperatures, thereby affecting its material strength and toughness. When the aircraft flies from the ground to an altitude of 10,000 meters, the temperature range that the windshield needs to withstand is about 40°C to -70°C. In addition to the decrease in toughness, the physical phenomenon of thermal expansion and contraction of the adhesive layer is also much greater than that of inorganic glass. After years of accumulation, there is a high risk that the electrothermal film layer and the conductive circuit will be attacked by water vapor due to the aging of the adhesive layer material and deteriorate, thereby causing the failure of the electric heating function. Even more seriously, when the electric heating layer is in direct contact with the adhesive layer, whenever the electric heating layer works, the heating power in each area will vary according to the ice formation situation. Some areas have a large power and instantly generate high-temperature areas, which also poses risks of thermal fatigue and thermal deterioration to the adhesive layer. This is one of the main failure reasons for the current aircraft windshield, that is, the failure points mostly concentrate on the adhesive layer between the outer glass and the middle glass and the bonding position between the adhesive layer and the electrothermal film layer.

[0006] As mentioned above, the electrothermal film of the existing aircraft windshield glass is placed on the inner surface of the outermost glass plate in front of the cockpit and is deposited on the glass surface in the form of a film layer. The material of the electrothermal film layer can be ITO, FTO, graphene, etc.; adjacent to a layer of PVB or TPU adhesive layer, which is used to bond the outermost glass plate (including the electrothermal film layer) to the aluminum-silicate glass plate in the middle layer to form a laminated sheet. This structural arrangement will inevitably cause the adhesive layer to be in direct contact with the electrothermal film layer and interact with each other. For example, when the electrothermal film layer is heated, it will have a thermal effect on the adjacent adhesive layer. In addition to the thermal expansion and contraction caused by the cold and hot cycle, the local high-temperature points caused by uneven heating will also damage the service life of the adhesive layer. For the two commonly used adhesive layers of PVB and TPU, the process temperature during lamination with the glass will fall within the range of 115-125°C. Both show excellent adhesive performance after the glass plates are laminated. However, some specially designed TPU can withstand cold down to -70°C, which is better than the cold resistance temperature of PVB at about -40°C. Therefore, when laminating the windshield glass of commercial airliners, TPU is preferably selected. Although the temperature application range of TPU can cover -70 to 80°C and can be applicable to the temperature range of the aircraft from the ground to 10,000 meters in altitude, most organic polymer materials will show embrittlement at low temperatures, especially when the temperature is lower than the glass transition temperature (T g ). When the temperature is lower than T g , the mechanical behavior of the material will change from viscoelasticity to rigidity. Taking TPU as an example, its T g will vary due to the chemical composition and polymer structure and is usually distributed in the range of -40°C to -60°C. When the TPU adhesive layer becomes rigid as the temperature drops, it will gradually lose its elasticity and become brittle. And if the windshield glass is curved, the interface between the TPU adhesive layer and the glass may accumulate stress due to temperature difference changes, and in severe cases, it will cause the adhesive layer to peel off from the glass, which will lead to the weakening of the overall structure of the windshield glass. Therefore, the timely heating of the electrothermal film layer can not only prevent the outer surface of the windshield glass from icing but also provide a certain temperature for the adhesive layer in a timely manner to avoid embrittlement. Although the electrothermal film layer can provide a warming effect for the TPU adhesive layer, the direct contact between the TPU adhesive layer and the electrothermal film layer, that is, the laminated structure where the two are closely attached together, still has the following disadvantages:

[0007] (1) Local scalding of the adhesive layer caused by uneven heating

[0008] Commercial aircraft have extremely high requirements for safety performance. Any factors that can affect flight safety need to be avoided and controlled in advance, and the safety of flight devices also needs to be monitored and managed at all times, especially for the crucial windshield glass. As mentioned above, when the electrothermal film layer of the windshield glass is bonded to the TPU adhesive layer, the heating power of the electrothermal film layer needs to match the curved shape of the windshield glass and the uneven icing condition on the outer surface. Although the electrothermal film layer itself is provided with a multi-point temperature monitoring device, the risk of local overheating still exists. The overheated area may cause defects such as local peeling, displacement sliding, and uneven thickness of the adhesive layer. These defects will in turn cause the peeling of the electrothermal film layer and the damage of the conductive circuit, ultimately affecting the overall safety of the windshield glass.

[0009] (2) Siphon phenomenon of the adhesive layer under thermal cycling

[0010] The adhesive layer itself has a certain degree of affinity for water vapor in the air, especially PVB itself has a relatively high water absorption. Generally speaking, the moisture content of the PVB film when it leaves the factory is about 0.25 - 0.55%. If it is not stored in a dry environment, when the water content is higher than 1%, it will affect the bonding ability and is usually discarded and no longer used. The adhesive layer that has already completed the glass lamination also needs to seal the periphery of the bonding layer to prevent water vapor in the air from gradually penetrating into the adhesive layer itself and the interfaces of the adhesive layer / glass and adhesive layer / electrothermal film layer. If the waterproof vapor seal around the bonding layer ages, is damaged by rubbing or impact, or peels off, water vapor will gradually seep into the adhesive layer. After the adhesive layer absorbs water vapor and then undergoes thermal cycling, a siphon pump-like effect will occur at this time. When the adhesive layer is heated, its volume expands, and the polymer network structure will accommodate more water vapor due to the expansion. When it cools, some of the water vapor condenses in the colloid. Due to the capillary action, it is very difficult to drive away these condensed waters. Such a cycle repeats, resulting in the gradual deep penetration of water vapor into the adhesive layer, ultimately leading to a decrease in the adhesion of the adhesive layer and causing water vapor to start corroding the conductive circuit and the electrothermal film layer. Summary of the Invention

[0011] To solve the above technical problems, the purpose of the present invention is to provide an electrothermal glass laminate, an electrothermal glass, and its preparation method and application. The present invention designs a novel electrothermal glass laminate as the outer electrothermal glass layer, so that the electrothermal film layer and the interlayer in the electrothermal glass are independent of each other and do not contact each other, which can improve the electroheating effect and overcome the disadvantage of the interlayer being adjacent to the electrothermal film.

[0012] To achieve the above purpose, the first aspect of the present invention provides an electrothermal glass laminate, which includes: a first inorganic glass plate located on the outside, a second inorganic glass plate placed opposite to the first inorganic glass plate, and an electrothermal film layer located between the first inorganic glass plate and the second inorganic glass plate;

[0013] Among them, the electrothermal film layer is divided into several regions, and there are gaps between the regions;

[0014] The first inorganic glass plate and the second inorganic glass plate are joined by cold laser welding at the peripheral edges and the gaps existing between the regions of the electrothermal film layer to form the electrothermal glass laminate.

[0015] In the present invention, the electrothermal film layer is divided into several regions, which can provide different electric powers and convert them into different amounts of heat to heat the electrothermal glass laminate at different positions. Moreover, the electrothermal glass laminate of the present invention is formed by welding the first inorganic glass and the second inorganic glass using cold laser under normal temperature conditions without using any solder. The outer electrothermal glass layer obtained by welding two glass plates without adhesive film bonding can achieve the effect of waterproof airtightness and has a strength not lower than that of the original glass plate (i.e., the glass plate with a thickness equal to the total thickness of the first inorganic glass plate and the second inorganic glass plate). For the specific content of cold laser welding, please refer to the content disclosed in CN114772950A.

[0016] In the above-mentioned electrothermal glass laminate, preferably, let the total thickness of the first inorganic glass plate and the second inorganic glass plate be x 0 and let the thickness of the first inorganic glass plate be x 1 , Then the value of R ranges from 0.3 > R > 0.05. By controlling R in the present invention, that is, by controlling the thickness ratio of the first inorganic glass plate and the second inorganic glass plate, better thermal efficiency can be provided and a better electric heating effect can be achieved. It has a better anti-icing function than the original glass plate (i.e., the glass plate with a thickness equal to the total thickness of the first inorganic glass plate and the second inorganic glass plate), and at the same time has a better anti-fogging effect on the glass inside the electrothermal film layer.

[0017] In the above-mentioned electrothermal glass laminate, preferably, the thickness of the first inorganic glass plate is 1 to 3 mm.

[0018] In the above-mentioned electrothermal glass laminate, preferably, the relationship and the following conditions represented by the following formula are satisfied among the electric heating power density of each region in the several regions divided by the electrothermal film layer, the area of each region in the several regions divided by the electrothermal film layer, the resistivity of the material of the electrothermal film layer, the thickness of the electrothermal film layer, and the ratio of the length to the width of each region in the several regions divided by the electrothermal film layer:

[0019]

[0020] Wherein, P is the electric heating power of each of several regions separated by the electrothermal film layer, in watts; S is the area of each of several regions separated by the electrothermal film layer, in square meters; P / S represents the electric heating power density of each of several regions separated by the electrothermal film layer; U is the energizing voltage of the electrothermal film layer, in volts; θ is the ratio of the length to the width of each of several regions separated by the electrothermal film layer; R S is the sheet resistance of the material of the electrothermal film layer, in ohms, and R S = ρ / d, where ρ is the resistivity of the material of the electrothermal film layer, in ohm-meters; d is the thickness of the electrothermal film layer, in meters;

[0021] At -40°C, P / S is not less than 3000 W / m 2 .

[0022] More preferably, when the total area of several regions separated by the electrothermal film layer is 0.7 to 1.1 m 2 , S is 0.2 to 0.4 m 2 .

[0023] More preferably, the ratio of the length to the width of each of several regions separated by the electrothermal film layer is 1 to 2.5.

[0024] It should be noted that, as described below, since the actual shape of the electrothermal glass of the present invention can adopt a curved surface and / or various irregular shapes, therefore, the area of each of several regions separated by the electrothermal film layer of the present invention and the length and width of each region are calculated based on the equivalent area of the electrothermal film layer, and the shape adopted by the equivalent area is a rectangle. Therefore, the length and width of each of several regions separated by the electrothermal film layer respectively refer to the length and width of this rectangle. By partitioning the electrothermal film layer and controlling d, θ, S, and the number of separated regions, etc. to satisfy the above relationships and conditions, the present invention can achieve the range of electric heating power density to be controlled under the given energizing voltage condition and the resistivity condition of the material of the electrothermal film layer, and thus can have excellent electrothermal efficiency, that is, energy-saving effect and heat transfer efficiency, so that the effects of preventing ice formation on the outer surface and fog formation on the inner surface of the windshield both reach the best.

[0025] In the above electrothermal glass laminate, preferably, the width of the gap between each of the regions separated by the electrothermal film layer is 0.5 to 3.5 mm, more preferably 0.8 to 3.0 mm.

[0026] In the above electrothermal glass laminate, preferably, the thickness of the electrothermal film layer is below 100 nm, more preferably below 70 nm.

[0027] In the above-mentioned electric heating glass laminate, preferably, the material of the electric heating film layer includes one or a combination of metal, inorganic metal oxide and graphene. More preferably, the material of the electric heating film layer includes Ag, ITO (In 2 O 3 :Sn)、FTO(SnO 2 :F), AZO (ZnO:Al) and graphene, etc., or a combination of one or more thereof.

[0028] The electric heating glass laminate of the present invention can be used as the outer electric heating glass layer of a windshield (especially an aircraft windshield), mainly used to provide an electric heating function. The present invention achieves at least the following effects by controlling R within the above range and controlling the electric heating power density as well as d, θ, ρ, S, etc. to satisfy the above relationship and conditions: (1) After the electric heating film layer is energized to generate heat, better heat transfer can be generated to both the inside and outside of the electric heating film layer, so that the effect of preventing ice formation on the outer surface of the windshield and fog formation on the inner surface is optimal; (2) Compared with the prior art, the time for heat transfer to the outer surface is shortened and energy consumption is reduced; (3) The interlayer can be kept at a normal use temperature, and the interlayer material will not become brittle due to overcooling, and lose strength and adhesion; (4) The temperature of the outer surface of the first inorganic glass plate (i.e., the outer surface of the windshield) can be slightly higher than the freezing point (about 1.7°C, i.e., about 35°F), thereby avoiding the problem of accelerated aging of the interlayer, conductive circuit, etc. caused by excessive temperature; (5) The heat loss such as free convection heat dissipation, thermal radiation heat dissipation, energy dissipation of collision of heated water droplets, and latent heat of evaporation of water droplets on the outer surface of the windshield is fully considered, so that the outer surface of the windshield achieves excellent anti-icing effect.

[0029] According to a specific embodiment of the present invention, preferably, the electric heating glass laminate further includes a conductive circuit, and the conductive circuit is connected to the electric heating film layer. It should be noted that when the first inorganic glass plate and the second inorganic glass plate are welded by cold laser, an access port for the wire circuit should be reserved. In addition, the shapes and areas of the several areas separated by the electric heating film layer mentioned above do not include the area connected to the conductive circuit.

[0030] In the above-mentioned electric heating glass laminate, preferably, the first inorganic glass plate and the second inorganic glass plate respectively include chemically tempered glass plates, physically tempered glass plates or semi-tempered glass plates, etc. The types of the first inorganic glass plate and the second inorganic glass plate can be the same or different as long as they are within this range.

[0031] In the above-mentioned electrothermal glass laminate, preferably, the materials of the first inorganic glass plate and the second inorganic glass plate respectively include one or a combination of several of aluminosilicate glass, lithium aluminosilicate glass, borosilicate glass, borosilicate aluminosilicate glass, soda-lime glass, etc. The materials of the first inorganic glass plate and the second inorganic glass plate may be the same or different, as long as they are within this range.

[0032] The second aspect of the present invention provides an electrothermal glass, which sequentially includes from outside to inside: an outer electrothermal glass layer, a first interlayer, an intermediate glass layer, a second interlayer, and an inner glass layer;

[0033] Among them, the outer electrothermal glass layer is the above-mentioned electrothermal glass laminate;

[0034] The intermediate glass layer includes a third inorganic glass plate;

[0035] The inner glass layer includes a fourth inorganic glass plate;

[0036] The outer electrothermal glass layer, the first interlayer, the intermediate glass layer, the second interlayer, and the inner glass layer are combined into a whole.

[0037] In the above-mentioned electrothermal glass, preferably, the thickness of the third inorganic glass plate is 7-15 mm, more preferably 8-11 mm.

[0038] In the above-mentioned electrothermal glass, preferably, the thickness of the fourth inorganic glass plate is 4-12 mm, more preferably 5-10 mm.

[0039] In the above-mentioned electrothermal glass, preferably, the third inorganic glass plate and the fourth inorganic glass plate respectively include chemically tempered glass plates, physically tempered glass plates, or semi-tempered glass plates, etc. The types of the third inorganic glass plate and the fourth inorganic glass plate may be the same or different, as long as they are within this range.

[0040] In the above-mentioned electrothermal glass, preferably, the materials of the third inorganic glass plate and the fourth inorganic glass plate respectively include one or a combination of several of aluminosilicate glass, lithium aluminosilicate glass, borosilicate glass, borosilicate aluminosilicate glass, soda-lime glass, etc. The materials of the third inorganic glass plate and the fourth inorganic glass plate may be the same or different, as long as they are within this range.

[0041] In the above-mentioned electrothermal glass, preferably, the thickness of the first interlayer is 2.2-6.0 mm, more preferably 3.0-5.3 mm.

[0042] In the above-mentioned electrothermal glass, preferably, the thickness of the second interlayer is 1.5-5.3 mm, preferably 2.2-4.5 mm.

[0043] In the above-mentioned electric heating glass, preferably, the materials of the first interlayer and the second interlayer respectively include one or a combination of several of TPU, PVB, EVA, SGP, etc.

[0044] According to a specific embodiment of the present invention, preferably, the shape of the electric heating glass includes a plane, a single curved surface, a double curved surface, a spherical surface, etc.

[0045] According to a specific embodiment of the present invention, preferably, the electric heating glass further includes a peripheral sealant, which is disposed around the entire periphery of the outer electric heating glass layer, the first interlayer, the intermediate glass layer, the second interlayer, and the inner glass layer for providing airtight packaging and edge protection.

[0046] The third aspect of the present invention provides a preparation method of the above-mentioned electric heating glass, which includes the following steps:

[0047] S1: Deposit an electric heating film layer on the surface of the first inorganic glass plate, and divide the electric heating film layer into several regions with gaps between the regions;

[0048] S2: Combine the first inorganic glass plate with the peripheral edge of the second inorganic glass plate and the gaps existing between the regions of the electric heating film layer by means of cold laser welding to form an outer electric heating glass layer (i.e., the electric heating glass laminate of the present invention);

[0049] S3: Bond the outer electric heating glass layer, the third inorganic glass plate, and the fourth inorganic glass plate together with the materials of the first interlayer and the second interlayer to form a first interlayer, a second interlayer, an intermediate glass layer, and an inner glass layer, and make the first interlayer located between the outer electric heating glass layer and the intermediate glass layer, and the second interlayer located between the intermediate glass layer and the inner glass layer to obtain the electric heating glass.

[0050] The fourth aspect of the present invention provides an application of the above-mentioned electric heating glass laminate and / or the above-mentioned electric heating glass in windshield glass, side windows, chord windows, and escape windows.

[0051] In the above-mentioned application, the electric heating glass laminate of the present invention can be independently applied to fields such as windshield glass, side windows, chord windows, and escape windows of transportation vehicles; it can also be applied to fields such as windshield glass, side windows, chord windows, and escape windows of transportation vehicles through a structural design of laminating with other glasses (such as the electric heating glass of the present invention).

[0052] In the above-mentioned application, preferably, the windshield glass includes windshield glass for airplanes, automobiles, rail transit vehicles, and windshield glass for ships and submersibles, etc.

[0053] In the electrothermal glass of the present invention, the electrothermal film layer and the interlayer are independent of each other and do not contact each other, overcoming the following defects existing in current aircraft windshield glass: ① local scalding of the adhesive layer caused by uneven heating and ② siphon phenomenon of the adhesive layer caused by thermal cycling. At the same time, the glass material currently used has passed strict certification. Therefore, without changing the glass material, conditions such as the thickness, strength, weight of the glass plate and the thickness of the interlayer it is paired with are also strictly regulated. The present invention separates the interlayer from the electrothermal film layer without affecting the original safety structure of the electrothermal glass. Considering the weight and strength of the electrothermal glass for the windshield, the total thickness of the first inorganic glass plate and the second inorganic glass plate of the present invention is equivalent to the thickness of the original outer glass plate. Therefore, the present invention does not increase the thickness of the glass plate nor the weight of the glass plate. The present invention arranges the electrothermal film layer in the middle of the two split glass plates (i.e., the first inorganic glass plate and the second inorganic glass plate), and uses an advanced cold laser welding process to re-weld the two split glass plates into one glass. The shape, thickness, and weight of the welded glass are the same as or very close to those of the original outer glass plate. The present invention uses this composite glass plate with the same thickness as the original outer glass plate but with an electrothermal film layer sandwiched in it to replace the original outer glass plate. The present invention arranges the electrothermal film layer between two glass plates to form one glass plate, but does not laminate the glass plates with an adhesive layer. As described above, the materials that can be used for the electrothermal film layer include metal thin films, such as silver; or metal oxide thin films, such as ITO, FTO, AZO; or graphene films, etc.; these film materials do not have adhesiveness at room temperature. The processes of the prior art are difficult to fix the non-adhesive electrothermal film between two glass plates at room temperature. The structural design of the present invention and the use of the cold laser welding process can not only form an outer electrothermal glass layer with electrothermal function, but also ensure that the combined outer electrothermal glass layer has strength and optical properties not lower than those of the outer glass plate of the original windshield glass, and can effectively prevent water vapor from seeping into the electrothermal film layer from the edge, and at the same time does not contact the interlayer to avoid deterioration of the interlayer, and also improves the energy-saving effect and heat transfer efficiency of the outer electrothermal glass layer.

[0054] At the same time, the present invention does not change the existing first interlayer, second interlayer, middle glass layer and inner glass layer, but integrates the composite glass plate with an electrothermal film layer sandwiched in it with the original first interlayer, second interlayer, middle glass layer and inner glass layer to form a complete windshield glass.

[0055] The present invention has at least achieved the following beneficial effects:

[0056] (1) Without changing the main structure of the existing standard-compliant windshield glass, the middle glass layer and inner glass layer that provide structural support strength, and the first interlayer and second interlayer all maintain the existing design, that is, it does not affect the safety structure and strength of the windshield glass.

[0057] (2) For the electrothermal glass laminate of the creative design of the present invention (i.e., the outer electrothermal glass layer), the electrothermal film layer is disposed between two relatively thin glass sheets and welded by cold laser. Its functions are to provide electrothermal heating and anti-icing. Since the electrothermal glass laminate is not a structural member, it will not affect the safety performance of the windshield glass. At the same time, due to its structural design and cold laser welding process, the electrothermal glass laminate overcomes the above-mentioned drawback of the laminated glass being adjacent to the electrothermal film and has a good electrothermal heating effect, thus having an excellent anti-icing effect. Moreover, since the electrothermal film layer in the electrothermal glass laminate is closer to the outer surface of the windshield glass, compared with the original windshield glass heating system, the electrothermal glass laminate of the present invention has better energy-saving effect and better heat transfer efficiency. And, the electrothermal film layer is divided into several regions, which can provide different electric powers and convert them into different amounts of heat for heating the electrothermal glass laminate at different positions. Furthermore, the electrothermal glass laminate of the present invention is formed by welding the first inorganic glass and the second inorganic glass with cold laser under normal temperature conditions without using any solder. The electrothermal glass laminate obtained by welding two glass plates without adhesive film bonding can achieve the effect of waterproof airtightness. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 The structural schematic diagram of the electrothermal glass laminate provided for the specific embodiment of the present invention.

[0059] Figure 2 The structural schematic diagram of the electrothermal glass provided for the specific embodiment of the present invention.

[0060] Figure 3 The structural schematic diagram of the aircraft windshield glass provided for the specific embodiment of the present invention.

[0061] Figure 4 The structural schematic diagram of the stainless steel plate group with a hollowed-out area in the specific embodiment of the present invention.

[0062] Figure 5 The structural schematic diagram of the cold laser welding structure in the specific embodiment of the present invention.

[0063] Figure 6 The curve of P / S value and the highest equilibrium temperature in the test example.

[0064] Explanation of the reference numerals in the drawings:

[0065] 1 - Outer electrothermal glass layer; 2 - First laminated layer; 3 - Intermediate glass layer; 4 - Second laminated layer; 5 - Inner glass layer; 101 - First inorganic glass plate; 102 - Second inorganic glass plate; 103 - Electrothermal film layer. SPECIFIC EMBODIMENTS

[0066] For a clearer understanding of the technical features, objectives, and beneficial effects of the present invention, the following detailed description of the technical solution of the present invention is provided, but it should not be construed as a limitation on the scope of implementation of the present invention.

[0067] Electrically Heated Glass Laminate

[0068] A specific embodiment of the present invention provides an electrothermal glass laminate, as Figure 1 shown, which includes: a first inorganic glass plate 101 located on the outside, a second inorganic glass plate 102 placed opposite to the first inorganic glass plate 101, and an electrothermal film layer 103 located between the first inorganic glass plate 101 and the second inorganic glass plate 102;

[0069] Among them, the electrothermal film layer 103 is divided into several regions, and there are gaps between the regions;

[0070] The peripheral edges of the first inorganic glass plate 101 and the second inorganic glass plate 102 and the gaps between the regions of the electrothermal film layer 103 are joined by cold laser welding to form an electrothermal glass laminate.

[0071] Among them, let the total thickness of the first inorganic glass plate 101 and the second inorganic glass plate 102 be x 0 , and let the thickness of the first inorganic glass plate 101 be x 1 , Then the value of R is 0.3 > R > 0.05.

[0072] The electric heating power density of each region in the several regions divided by the electrothermal film layer 103, the area of each region in the several regions divided by the electrothermal film layer 103, the resistivity of the material of the electrothermal film layer 103, the thickness of the electrothermal film layer 103, and the ratio of the length to the width of each region in the several regions divided by the electrothermal film layer 103 satisfy the relationship and the following conditions represented by the following formula:

[0073]

[0074] Among them, P is the electric heating power of each region in the several regions divided by the electrothermal film layer 103, with the unit of watt; S is the area of each region in the several regions divided by the electrothermal film layer 103, with the unit of square meter; P / S represents the electric heating power density of each region in the several regions divided by the electrothermal film layer 103; U is the energization voltage of the electrothermal film layer 103, with the unit of volt; θ is the ratio of the length to the width of each region in the several regions divided by the electrothermal film layer 103; R S is the sheet resistance of the material of the electrothermal film layer 103, with the unit of ohm, and R S = ρ / d, where ρ is the resistivity of the material of the electrothermal film layer 103, with the unit of ohm-meter; d is the thickness of the electrothermal film layer 103, with the unit of meter;

[0075] At -40°C, P / S is not less than 3000 W / m 2 ;

[0076] When the total area of several regions separated by the electrothermal film layer 103 is 0.7 - 1.1 m 2 S is 0.2 - 0.4 m 2 ;

[0077] The ratio of the length to the width of each region in several regions separated by the electrothermal film layer 103 is 1 - 2.5.

[0078] Electrically Heated Glass

[0079] The specific embodiment of the present invention provides an electrothermal glass. As Figure 2 shown, the electrothermal glass sequentially includes from outside to inside: an outer electrothermal glass layer 1, a first interlayer 2, an intermediate glass layer 3, a second interlayer 4, and an inner glass layer 5;

[0080] Among them, the outer electrothermal glass layer 1 includes: a first inorganic glass plate 101 located on the outside, a second inorganic glass plate 102 placed opposite to the first inorganic glass plate 101, and an electrothermal film layer 103 located between the first inorganic glass plate 101 and the second inorganic glass plate 102;

[0081] The electrothermal film layer 103 is separated into several regions, and there are gaps between the regions;

[0082] The peripheral edges of the first inorganic glass plate 101 and the second inorganic glass plate 102 and the gaps between the regions of the electrothermal film layer 103 are combined by cold laser welding to form the outer electrothermal glass layer 1;

[0083] The intermediate glass layer 3 includes a third inorganic glass plate;

[0084] The inner glass layer 5 includes a fourth inorganic glass plate;

[0085] The outer electrothermal glass layer 1, the first interlayer 2, the intermediate glass layer 3, the second interlayer 4, and the inner glass layer 5 are combined into an integral whole.

[0086] The electrothermal glass provided by the present invention can be used as a windshield, such as an aircraft windshield, an automobile windshield, a windshield of a rail transit vehicle, and a windshield of a ship and a submersible, etc., and is preferably used as an aircraft windshield.

[0087] The structure of the aircraft windshield of the present invention is as Figure 3 shown. Looking forward from the cockpit is the aircraft windshield, which can be divided into a left windshield and a right windshield, and the structures of the two are symmetrical; extending backward from the left and right windshields are the aircraft side windows.Figure 3 It shows several regions separated by the electrothermal film layer 103 and the regions for cold laser welding. The several regions separated by the electrothermal film layer 103 and the welding regions are on the same layer but have their own planar positions. By dividing the electrothermal film layer 103 into several regions in the present invention, different electric powers can be provided and converted into different amounts of heat to heat the outer electrothermal glass layer 1 at different positions, so as to meet the usage requirements of windshield glass, especially aircraft windshield glass. Moreover, the present invention uses the cold laser welding process, which makes the division of each region of the electrothermal film layer 103 and the manufacturing process of the electrothermal glass more precise and effective. At the same time, through the structural design and cold laser welding process of the present invention, the electrothermal film and the interlayer film are successfully separated, realizing a technological leap of the electrothermal glass as a windshield glass.

[0088] Cold Laser Welding

[0089] The first inorganic glass plate 101 and the second inorganic glass plate 102 of the present invention are joined by cold laser welding at the gaps existing between their peripheral edges and each region of the electrothermal film layer 103. The electrothermal film layer 103 is arranged between the first inorganic glass plate 101 and the second inorganic glass plate 102 in the present invention, but no adhesive film is used for bonding. As described above, the material of the electrothermal film layer is metal, or inorganic metal oxide, or graphene, etc., which does not have adhesiveness, and it is difficult to complete the fastening and laminating of two glass plates with a non-adhesive electrothermal film layer sandwiched in the middle by other processing techniques. However, the present invention uses cold laser welding to form the outer electrothermal glass layer 1, ensuring that the outer electrothermal glass layer 1 has strength and optical properties not lower than those of the existing outer glass plate, and can effectively prevent water vapor from infiltrating from the edge into the electrothermal film layer 103, causing deterioration and oxidation of the electrothermal film and conductive circuits, etc. At the same time, it does not contact the interlayer film to avoid deterioration of the interlayer film.

[0090] The present invention combines the first inorganic glass plate 101 coated with an electrothermal film layer 103 and the second inorganic glass plate 102 into one piece of glass by means of cold laser welding in a dot, line, or surface welding manner, namely the outer electrothermal glass layer 1. This not only ensures the heating function of the electrothermal film layer 103 but also enhances the toughness, waterproof, and insulation capabilities of the outer electrothermal glass layer 1. This cold laser welding does not require any chemical media such as solder or interface activators and is an efficient, energy-saving, and environmentally friendly glass welding process that can be carried out at room temperature. Since it is welded at room temperature, the two glass plates are combined into one piece of glass by the plasma high-energy reaction instantaneously generated by femtosecond or picosecond lasers at the set positions. The welded joints of the outer electrothermal glass layer 1 after cold laser welding can be understood as being fused into one body. Therefore, its density and bonding strength are equivalent to those of glass fusion, far beyond what can be compared with the traditional glass lamination bonded with glue. One of the characteristics of cold laser welding is that the plasma high-energy thermal reaction process of each welding point is below 20 picoseconds (Pico-second). The chemical reaction of the reorganization of the glass molecular structure has ended before the heat has spread outward from the welding point. Therefore, it is called cold laser welding and does not generate thermal stress. Thus, there is no need to reheat and cool slowly after welding to eliminate stress.

[0091] The present invention uses cold laser welding to form the outer electrothermal glass layer 1, which has a strength not lower than that of the existing outer glass plate (i.e., a glass plate with a thickness equal to the total thickness of the first inorganic glass plate and the second inorganic glass plate), and even an enhanced strength. For example, two sodium-calcium glass or aluminosilicate glass plates with thicknesses of 0.9 mm and 2.1 mm are used as the first inorganic glass plate 101 and the second inorganic glass plate 102 respectively. After cold laser welding, it is equivalent to forming a 3-mm-thick glass. If the glass plates are chemically strengthened in advance, then for the two glass plates, a total of four glass plate surfaces are chemically strengthened. After cold laser welding and lamination, its strength is greater than that of a 3-mm glass with only two surfaces strengthened.

[0092] When performing cold laser welding, except for the positions where the reserved conductive lines etc. (which may also include temperature sensors and signal lines) are connected, the gaps between the peripheral edges of the first inorganic glass plate 101 and the second inorganic glass plate 102 and between the regions of the electrothermal film layer 103 are all the positions for cold laser welding. The electrothermal films in each region can be partitioned and sealed by dot, line, or surface welding methods respectively.

[0093] In some specific embodiments, when using cold laser welding, the number of welding lines is determined according to the following formula:

[0094]

[0095] where N is the number of welding lines, and the unit is strip;

[0096] w is the average width of the bonding wire, in mm;

[0097] S sealing is the welding strength of the welded sealing block, in N / mm 2 ;

[0098] α is the thermal expansion coefficient of the first inorganic glass plate 101, in °C -1 ;

[0099] ΔT is the temperature difference between the two surfaces (the two surfaces in the thickness direction) of the outer electrothermal glass layer 1 formed after welding, in °C;

[0100] E is the elastic modulus (i.e., Young's modulus) of the first inorganic glass plate 101, in MPa;

[0101] H is the thickness of the first inorganic glass plate 101 that expands due to heat, in mm.

[0102] In some specific embodiments, the number of the bonding wires ≥ 2.

[0103] In some specific embodiments, the pulse width at half maximum (Pulse Width, FWHM, or pulse duration) of the laser pulse used in the cold laser is below 20 picoseconds.

[0104] In some specific embodiments, the wavelength of the laser used in the cold laser welding is 800 nm - 1600 nm, such as 800 nm, 1045 nm, 1558 nm, 1064 nm, with 1064 nm being preferred.

[0105] In some specific embodiments, the repetition rate of the laser used in the cold laser is 1 Hz - 10 MHz. For example, but not limited to: the picosecond laser of Wuhan Raycus Fiber Laser Technologies Co., Ltd., the pulse width at half maximum of the laser pulse is 800 fs (i.e., 0.8 ps), and the laser of the model IceFyre 1064 - 50 of MKS Spectra-Physics, the pulse width at half maximum of the laser pulse is 10 ps. Different laser wavelengths combined with different operating parameters can produce different welding effects, but all can firmly weld the first inorganic glass plate 101 and the second inorganic glass plate 102 together. The laser wavelengths, pulse repetition rates, and pulse durations that have been proven to be applicable to glass laser welding are summarized in Table 1 below.

[0106] Table 1

[0107] Laser Wavelength Repetition Rate Pulse Duration 800nm 1kHz 85fs 1045nm 500kHz to 1MHz 350 to 400fs 1558nm 500kHz 950fs 1064nm 500kHz to 1MHz 10ps to 325fs

[0108] In some specific embodiments, the first inorganic glass plate 101 and the second inorganic glass plate 102 at the solder joint position must be closely attached, and the gap between the first inorganic glass plate 101 and the second inorganic glass plate 102 at the welding part is less than 40 μm, preferably less than 25 μm.

[0109] In some specific embodiments, the width of the bonding wire is 20 μm or less, preferably less than 5 μm.

[0110] In some specific embodiments, the welding strength of the bonding wire is greater than the thermal expansion shear stress between the first inorganic glass plate 101 and the second inorganic glass plate 102 being welded; preferably, the welding strength of the bonding wire is at least greater than 1 MPa or meets the following conditions:

[0111]

[0112] wherein, S sealing is the welding strength, with the unit of MPa;

[0113] α is the thermal expansion coefficient of the first inorganic glass plate 101, with the unit of °C -1 ;

[0114] ΔT is the temperature difference between the two surfaces (the two surfaces in the thickness direction) of the outer electrothermal glass layer 1 formed after welding, with the unit of °C;

[0115] E is the elastic modulus (i.e., Young's modulus) of the first inorganic glass plate 101, with the unit of MPa;

[0116] H is the thickness of the first inorganic glass plate 101 that expands due to heat, with the unit of mm;

[0117] d is the width of the welding and sealing area, with the unit of mm.

[0118] In some specific embodiments, the spacing distance between the bonding wires is 150 μm or more, and the depth of the bonding wires is 20 μm or more.

[0119] Preparation Method of Electrically Heated Glass

[0120] As Figure 2 shown, the preparation process flow of the electrothermal glass with the structure is: hot bending forming → chemical tempering → electrothermal film layer coating → cold laser welding → glass lamination. The specific description is as follows:

[0121] Step 1: Hot bending forming

[0122] Take lithium aluminosilicate glass with a thickness of 0.9 mm as the first inorganic glass plate 101, lithium aluminosilicate glass with a thickness of 2.1 mm as the second inorganic glass plate 102, and two pieces of lithium aluminosilicate glass with a thickness of 9 mm as the third and fourth inorganic glass plates. The size of the second inorganic glass plate 102 is slightly smaller than that of the first inorganic glass plate 101. For example, the width of the second inorganic glass plate 102 is 10 mm smaller than that of the first inorganic glass plate 101, and the lengths are the same; the sizes of the first inorganic glass plate 101, the third inorganic glass plate, and the fourth inorganic glass plate are the same. The four glass plates are heat-bent and formed by the heat-bending process in the prior art to make the curvatures of the four glass plates consistent.

[0123] Step 2: Chemical tempering (i.e., chemical strengthening)

[0124] The four heat-bent and formed glass plates are chemically tempered by the ion exchange method in the prior art.

[0125] Step 3: Electrothermal film layer coating

[0126] Cover a stainless steel plate group with a thickness of 2 mm and a hollow area on the surface of the chemically tempered first inorganic glass plate 101. The curvature of the stainless steel plate group is the same as that of the first inorganic glass plate 101, and the outer dimensions of the stainless steel plate group are the same as those of the first inorganic glass plate 101. The width of its non-hollow area is 3 mm / 10 mm. As Figure 4 shown, and fix the stainless steel plate group on the surface of the first inorganic glass plate 101 with high-temperature tape. Place the stainless steel plate group upward and the first inorganic glass plate 101 downward (relative to the coating direction), and use a vertical coating device to perform ITO coating. The hollow area will be evenly coated with an electrothermal film, such as an ITO film, to obtain an electrothermal film layer 103 with a thickness of 70 nm. Therefore, the electrothermal film layer 103 is divided into several regions, and there are gaps between the regions. The width of the gaps between the regions divided by the electrothermal film layer 103 is 3 mm.

[0127] Step 4: Cold laser welding

[0128] The laser parameters used in this embodiment are shown in Table 2 below.

[0129] Table 2

[0130] Type of Laser Light Source Femtosecond Infrared Solid-State Laser Central Wavelength 1064nm Pulse Width <800fs Repetition Frequency ≤1MHz Maximum Single Pulse Energy 100μJ <![CDATA[Beam quality M 2 > ≤1.2 Power Stability <3％ Spot Diameter 50μm Laser Power 9W

[0131] Remove the stainless steel plate group, stack the first inorganic glass plate 101 coated with the electrothermal film layer 103 and the second inorganic glass plate 102 after chemical tempering in central alignment, with the electrothermal film layer 103 sandwiched between the two glass plates. Use a femtosecond infrared solid-state laser to weld together the peripheral edges of the first inorganic glass plate 101 and the second inorganic glass plate 102 and the gaps existing between the regions of the electrothermal film layer 103 (i.e., the regions not coated with the electrothermal film layer 103) to form the outer electrothermal glass layer 1. Each welding area has 10 welding lines, the spacing between the welding lines is 0.2 mm, the width of the welding lines is 15 μm, the depth of the welding lines is 110 μm, the welding strength of the welding lines is 19 MPa, and the schematic diagram of the welding structure is as shown in Figure 5 shown (in order to clearly show the welding lines, Figure 5 the welding lines are simplified to 5 in Figure 5 ). After cold laser welding, the electrothermal film layer 103 is welded and protected between the first inorganic glass plate 101 and the second inorganic glass plate 102. As shown in

[0132] Step 5: Glass laminating

[0133] Use a TPU film to laminate the third inorganic glass plate, the fourth inorganic glass plate after chemical tempering, and the outer electrothermal glass layer 1 together under the conditions of 150 °C and 2 MPa to form the first laminating layer 2, the second laminating layer 4, the middle glass layer 3, and the inner glass layer 5, and make the first laminating layer 2 located between the outer electrothermal glass layer 1 and the middle glass layer 3, and the second laminating layer 4 located between the middle glass layer 3 and the inner glass layer 5 to obtain electrothermal glass. The thickness of the first laminating layer 2 is 4.5 mm, and the thickness of the second laminating layer 4 is 2.28 mm.

[0134] In the above description, let the total thickness of the first inorganic glass plate 101 and the second inorganic glass plate 102 be x 0 , and let the thickness of the first inorganic glass plate 101 be x 1 , then the value of R is 0.3.

[0135] The electrothermal film layer 103 is divided into several regions in a direction parallel to the width of the electrothermal film layer 103. The several regions divided by the electrothermal film layer 103 are rectangular in shape (ignoring the regions for connecting conductive lines).

[0136] The electric heating power density of each region in the several regions divided by the electrothermal film layer 103, the area of each region in the several regions divided by the electrothermal film layer 103, the resistivity of the material of the electrothermal film layer 103, the thickness of the electrothermal film layer 103, and the ratio of the length to the width of each region in the several regions divided by the electrothermal film layer 103 satisfy the relationship represented by the following formula and the following conditions:

[0137]

[0138] Among them, P is the electric heating power of each of several regions separated by the electrothermal film layer 103, with the unit of watt (W); S is the area of each of several regions separated by the electrothermal film layer 103 (i.e., the area of each region that can generate heat after being energized), with the unit of square meter (m 2 ); P / S represents the electric heating power density of each of several regions separated by the electrothermal film layer 103 (i.e., the electric heating power per unit area); U is the energized voltage of the electrothermal film layer 103, with the unit of volt (V); θ is the ratio of the length to the width of each of several regions separated by the electrothermal film layer 103; R S is the sheet resistance of the material of the electrothermal film layer 103, with the unit of ohm (Ω), and R S = ρ / d, where ρ is the resistivity of the material of the electrothermal film layer 103, with the unit of ohm meter (Ωm); d is the thickness of the electrothermal film layer 103, with the unit of meter (m);

[0139] When the external environmental temperature is -40°C, P / S is not less than 3000 W / m 2 ;

[0140] When the total area of several regions separated by the electrothermal film layer 103 is between 0.7 and 1.1 m 2 , S is between 0.2 and 0.4 m 2 ;

[0141] The ratio of the length to the width of each of several regions separated by the electrothermal film layer 103 is 1 to 2.5.

[0142] Taking the ITO film as an example, if the resistivity (ρ) of the ITO film is 5×10 -7 Ωm, the selected electric heating power density (P / S) is 7750 W / m 2 , and the energized voltage (U) is 220 V. The total area of several regions separated by the electrothermal film layer 103 adopted is 0.9 m 2 (ignoring the regions where the conductive lines are connected), then it is necessary to divide the total area of 0.9 m 2 into several regions (although the electrothermal glass in this embodiment is a curved surface design, it is calculated with the equivalent area), and the thickness (d) of the electrothermal film layer 103, the area (S) of each of several regions separated by the electrothermal film layer 103, the ratio (θ) of the length to the width of each of several regions separated by the electrothermal film layer 103, and the number of separated regions must satisfy the relationship represented by the above formula and the above conditions in order to meet the specified voltage, resistivity, and electric heating power density.

[0143] For 0.9 m 2For the total area, in this embodiment, it is divided into 3 regions, and the area (S) of each region is 0.3 m 2 . The numerical values of different d and θ are shown in Table 3 below. At the same time, based on actual applications, the length value of each region can be selected, and then the width value can be determined according to θ.

[0144] Table 3

[0145] d (nm) Rs (Ω) θ Length (m) Width (m) <![CDATA[S(m 2 )]]> 20 25.00 0.83 0.500 0.600 0.30 22 22.73 0.92 0.524 0.572 0.30 24 20.83 1.00 0.548 0.548 0.30 26 19.23 1.08 0.570 0.526 0.30 28 17.86 1.17 0.591 0.507 0.30 30 16.67 1.25 0.612 0.490 0.30 32 15.63 1.33 0.632 0.475 0.30 34 14.71 1.42 0.652 0.460 0.30 36 13.89 1.50 0.671 0.447 0.30 38 13.16 1.58 0.689 0.435 0.30 40 12.50 1.67 0.707 0.424 0.30 42 11.90 1.75 0.724 0.414 0.30 44 11.36 1.83 0.741 0.405 0.30 46 10.87 1.92 0.758 0.396 0.30 48 10.42 2.00 0.774 0.387 0.30 50 10.00 2.08 0.790 0.380 0.30 52 9.62 2.16 0.806 0.372 0.30 54 9.26 2.25 0.821 0.365 0.30 56 8.93 2.33 0.836 0.359 0.30 58 8.62 2.41 0.851 0.352 0.30 60 8.33 2.50 0.866 0.347 0.30 62 8.06 2.58 0.880 0.341 0.30 64 7.81 2.66 0.894 0.336 0.30 66 7.58 2.75 0.908 0.330 0.30 68 7.35 2.83 0.922 0.326 0.30 70 7.14 2.91 0.935 0.321 0.30 72 6.94 3.00 0.948 0.316 0.30 74 6.76 3.08 0.961 0.312 0.30 76 6.58 3.16 0.974 0.308 0.30 78 6.41 3.25 0.987 0.304 0.30 80 6.25 3.33 1.000 0.300 0.30 82 6.10 3.41 1.012 0.296 0.30 84 5.95 3.50 1.024 0.293 0.30 86 5.81 3.58 1.036 0.289 0.30 88 5.68 3.66 1.048 0.286 0.30 90 5.56 3.75 1.060 0.283 0.30 92 5.43 3.83 1.072 0.280 0.30 94 5.32 3.91 1.084 0.277 0.30 96 5.21 4.00 1.095 0.274 0.30 98 5.10 4.08 1.106 0.271 0.30 100 5.00 4.16 1.118 0.268 0.30

[0146] In the following test examples, more advanced graphene will be used as the material for the electrothermal film layer. Although the above ITO film has been used as the electrothermal film layer material for aircraft windshield glass for more than 50 years, due to the newly developed graphene material in recent years, it is superior to the traditional ITO film material in terms of conductivity, transparency, moisture resistance, temperature resistance, chemical stability, etc. Therefore, the electrothermal film layer in the following test examples will all use graphene material. No matter which electrothermal film material is used, it is applicable to the present invention.

[0147] Test Example 1: The electrothermal power required to maintain 1.5 °C when the bottom glass is not insulated and the outer surface of the cover glass has been heated to 1.5 °C under different R values and different ambient temperatures

[0148] In this test, a humid and heat exchange simulation environmental aging low-temperature type test chamber (Shenzhen Orihara Co., Ltd.) is used as the test environment. The length and width of the glass sample for testing are 260 mm × 260 mm. The bottom plate is soda-lime glass with a thickness of 8 mm, and the cover plates are soda-lime glass with thicknesses of 0.7 mm (R = 0.08) and 4 mm (R = 0.33) respectively. The simulated electrothermal film layer is in the middle of the bottom plate and the cover plate. In this test, graphene is used as the material for the electrothermal film layer, and the thickness of the electrothermal film layer is about 18 nm. The electrothermal film layer is equipped with appropriate heating modules and temperature control modules, and an on-off type temperature controller is used for temperature control. A temperature sensor is placed at the center point of the cover plate, using Pt-100 material, and the temperature is measured close to the outer surface of the cover glass. Both the outer sides of the cover plate and the bottom plate are directly exposed to the cold air in the low-temperature type test chamber, and the relative humidity in the test chamber is set to 50%. The electrothermal power measured here refers to the electrothermal power required to raise the temperature from the ambient temperature to 1.5 °C on the outer side of the cover plate; this test is carried out under the condition that the bottom plate is not insulated, so the heat of the electrothermal film layer is transferred to the upper cover plate and the lower bottom plate simultaneously.

[0149] The test results are shown in Table 4 below.

[0150] Table 4

[0151] Cover Plate Thickness Corresponding R Value Ambient Temperature (°C) -30 -20 -10 0.7mm 0.08 Heating Power at Constant Temperature (W) 34 24 13 4mm 0.33 Heating Power at Constant Temperature (W) 86 39 23

[0152] As can be seen from the data in Table 4, under the same bottom plate condition, the electric heating power required to maintain the outer surface temperature at 1.5 °C when the cover plate thickness is 0.7 mm (corresponding to R = 0.08) is less than that when the thickness is 4 mm (corresponding to R = 0.33). And as the ambient temperature gradually increases from -30 °C to -10 °C, the required electric heating power will also gradually decrease. However, no matter at which ambient temperature, the cover plate glass with a thickness of 4 mm requires more heat than the 0.7 mm glass to maintain the outer surface temperature at 1.5 °C.

[0153] Test Example 2: Different R values, different ambient temperatures, bottom plate glass insulation, the electric heating power required for the outer surface of the cover plate glass to rise from the ambient temperature to 1.5 °C (differences from Test Example 1: ① bottom plate insulation, ② the electric heating power required for the heating process from the ambient temperature to 1.5 °C)

[0154] The samples and devices used in this test are basically the same as those in Test Example 1. The only difference is that a foamed plastic heat insulation board is added under the bottom plate glass. The heat transfer coefficient of this heat insulation board is 2.16 W / m 2 ·K, and it can be considered that the heat generated by the electrothermal film layer is only transmitted outward in the direction of the cover plate, and is blocked by the heat insulation board in the bottom plate direction. The required electric heating power for heating is obtained by integrating the instantaneous electric heating power corresponding to each temperature point in the heating stage and then taking the average value with respect to the heating time.

[0155] The test results are shown in Table 5 below.

[0156] Table 5

[0157]

[0158] As can be seen from the data in Table 5 above, the smaller the R value (such as 0.08), the smaller the electric heating power for heating under different ambient temperatures. At the same time, it also shows that it takes a relatively short time to reach the target temperature of 1.5 °C from the ambient temperature.

[0159] Test Example 3: At the same ambient temperature of -5 °C and with the bottom plate glass in the insulated state, the electric heating power and the heating-up time required to reach 1.5 °C for different R values

[0160] The device for this test is basically the same as that in Test Example 2, but the thickness of the cover plate glass is changed to 2.00 mm, 2.84 mm, and 4.86 mm, and the electric heating power and heating-up time required for the cover plate glass with different thicknesses to be heated from the ambient temperature of -5 °C to 1.5 °C are tested.

[0161] The test results are shown in Table 6 below.

[0162] Table 6

[0163] Cover Plate Thickness (mm) Corresponding R Value Electric Heating Power (W) Heating Time (sec) 2 0.2 21.2 21.4 2.84 0.26 26.1 38.8 4.86 0.38 33.1 76

[0164] As can be seen from the data in Table 6 above, at the same ambient temperature, as the value of R increases, that is, as the thickness of the cover glass increases, the electric heating power required to heat the outer surface of the cover glass to 1.5 °C also increases, and the time required to heat to the target temperature also increases significantly synchronously. And when R exceeds the scope of the present invention (i.e., when R > 0.3), the time required to heat to the target temperature increases significantly.

[0165] Test Example 4: Discussion on Electrothermal Characteristics ①: Electroheating Effect with the Same Voltage, the Same Area but Different Aspect Ratios

[0166] The electroheating effect of the graphene electrothermal film layer applied to the windshield electrothermal glass can be verified by the following experiment. The thickness of the glass coated with the graphene electrothermal film layer is 3.91 mm, the thickness of the graphene electrothermal film layer is about 18 nm, and the sheet resistance is 12.42 Ω. This glass is used as the bottom glass, and silver paste is used as the positive and negative electrodes and connected to an external fixed voltage. An insulating board is placed below the bottom to control the heat flow to be only delivered in the direction of the cover. The thickness of the cover glass is 1.11 mm, and the external voltage is 8.4 V. The sizes and aspect ratio values of the electrothermal film layer samples are shown in Table 7 below.

[0167] Table 7

[0168] Sample Number Length (mm) Width (mm) Length: Width <![CDATA[Area (mm 2 )]]> θ1 25 25 1 625 θ2 35.4 17.7 2 625 θ4 50 12.5 4 625

[0169] The samples are placed in a thermostatic and humidity-controlled thermal cycling test chamber and tested at three temperatures of -10 °C, -20 °C, and -40 °C respectively. The test results are shown in Table 8 below.

[0170] Table 8

[0171]

[0172] As can be seen from the data in Table 8 above, at different ambient temperatures, the heating-up time is always the shortest when the aspect ratio θ = 1, but the heat required to heat up to 1.5 °C is usually higher, which is a reasonable phenomenon because its P / S ratio is higher. Similarly, when the P / S ratio is higher, at a fixed ambient temperature, the final equilibrium temperature that can be reached is also the highest. For example, in an environment of -10 °C, the highest equilibrium temperature when θ = 1 is 87.8 °C. As the aspect ratio increases, the P / S value also decreases, and its final equilibrium temperature also drops to 22.8 °C when θ = 4. The same phenomenon also repeats in the environments of -20 °C and -40 °C.

[0173] Among them, it should be specifically pointed out that when the θ value increases, it means that the P / S value decreases, which will affect the final equilibrium temperature. The meaning of this equilibrium temperature is that if the voltage is fully turned on, at a certain ambient temperature, the final equilibrium temperature that the outer surface of the cover plate can reach. This final equilibrium temperature must exceed the target set temperature of the windshield. For example, the target temperature set here is 1.5 °C. If the final equilibrium temperature fails to exceed 1.5 °C, it means that the heating capacity of the electrothermal film layer cannot meet the de-icing requirements of the windshield. From the data in Table 8 above, it can be seen that when the ambient temperature is -40 °C, if θ = 4, the final equilibrium temperature can only reach -6.4 °C. That is to say, this is the highest temperature under this condition, and in any case, the electrothermal film layer cannot melt the ice on the outer surface of the cover plate. In other words, it means that in an environment of -40 °C, the P / S value of the electrothermal film layer is 2272 W / m 2 is not large enough to melt the ice layer. Therefore, the present invention controls the P / S at -40 °C to be not less than 3000 W / m 2 , and controls the ratio of the length to the width of each of the several regions separated by the electrothermal film layer to be 1 - 2.5, which can achieve a better electrothermal effect; while if the P / S and θ values are not within the scope of the present invention, a good electrothermal effect cannot be achieved.

[0174] Test Example 5: Discussion on Electrothermal Characteristics ②: Under the same ambient temperature, the influence of changing the voltage on the electrothermal effect of electrothermal glass with the same area but different aspect ratios

[0175] Similar to the test device in Test Example 4, but the ambient temperature is fixed at -40 °C, and the voltage is increased to 3 types, namely 4.2 V, 8.4 V, and 16.8 V. The test results are shown in Table 9 below.

[0176] Table 9

[0177]

[0178] From the data in Table 9 above, it can be found that for the same glass combination and test environment, the only condition changed is the heating source voltage. In an environment of -40 °C, when the voltage is 4.2 V, the P / S corresponding to the aspect ratios θ of 1, 2, and 4 is 2272, 1136, and 568; at this time, it can be found that the final equilibrium temperatures are all far below 1.5 °C. That is to say, a voltage of 4.2 V (the P / S at -40 °C is less than 3000 W / m 2)It is unable to provide sufficient energy to heat the cover glass, and naturally it is also unable to achieve the effect of de-icing the outer surface of the windshield. The case of 8.4V has been described in Test Example 4 and will not be elaborated here. The case of 16.8V can be said to be the opposite of the case of 4.2V. The P / S values at θ values of 1, 2, and 4 are 36359, 18180, and 9090 respectively. At this time, the P / S values are relatively high. Therefore, the time required to heat from -40°C to 1.5°C is significantly reduced. The heating time at θ = 1 is only 49 seconds, which is a relatively short time for aircraft windshield de-icing. However, along with the advantage of short-time heating, another risk is also increased. From the data in Table 9, it can be seen that its final equilibrium temperature is as high as 235°C, which is much higher than the softening point of the adhesive layer used in the windshield glass combination and is harmful to the adhesive layer and needs to be avoided. Therefore, when using a relatively high P / S value, an appropriate thermal control system needs to be configured. Whether it is on-off control or PID control, it is necessary to ensure that the glass surface temperature does not approach the tolerance temperature of the adhesive layer.

[0179] Test Example 6: Discussion on the P / S value

[0180] Similar to the test device in Test Example 5, in an ambient temperature of -40°C, with the same glass plate thickness and structural combination, the same test environment, and the same heating area, but the aspect ratio θ and voltage can be changed. Just like the data in Test Example 5, taking out the P / S value and the highest equilibrium temperature and plotting and analyzing them, we can obtain Figure 6 .

[0181] From Figure 6 the curve in, it can be seen that as the P / S value increases, the final equilibrium temperature T max also gradually increases. At this time, draw a horizontal line at 1.5°C, and it can be observed that this horizontal line approximately intersects the curve at around P / S = 3000. Therefore, when the ambient temperature is -40°C, regardless of the voltage, aspect ratio, or sheet resistance of the electrothermal film layer used in the electrothermal glass, it is necessary to maintain the P / S value greater than approximately 3000 W / m 2 , only then is it possible to heat the cover glass to 1.5°C and achieve the de-icing effect. This verifies the good electrothermal effect achieved by controlling the P / S within the scope of the present invention. In addition, the larger the P / S value, the shorter the heating time, but the higher the final equilibrium temperature. At this time, it is necessary to use a temperature control system to ensure that the cover glass surface remains at 1.5°C and the temperature should not continue to rise to cause damage to other materials in the windshield electrothermal glass.

[0182] Similarly, when the external ambient temperature is lower than -40°C, such as -70°C, which is the temperature that may be encountered at an altitude of more than 10,000 meters, the lowest P / S value will obviously be higher than 3000 W / m 2The altitude at which different aircraft are airworthy will vary. In the present invention, only the ambient temperature of -40°C, which is generally encountered, is used as the verification point, and the minimum P / S value ≥ 3000 W / m 2 @ is proposed under the condition of -40°C, and the good electrothermal effect achieved thereby is verified.

Claims

1. An electric heating glass laminate, comprising: A first inorganic glass plate located on the outside, a second inorganic glass plate placed opposite to the first inorganic glass plate, and an electric heating film layer located between the first inorganic glass plate and the second inorganic glass plate; Wherein, the electric heating film layer is divided into several areas, and there are gaps between the areas; The peripheral edges of the first inorganic glass plate and the second inorganic glass plate and the gaps between the various regions of the electric heating film layer are combined by cold laser welding to form the electric heating glass laminate.

2. The electric heating glass laminate according to claim 1, wherein The total thickness of the first inorganic glass plate and the second inorganic glass plate is x0, and the thickness of the first inorganic glass plate is x1. Then the value of R is 0.3>R>0.

05.

3. The electric heating glass laminate according to claim 2, wherein: The thickness of the first inorganic glass plate is 1 to 3 mm.

4. The electric heating glass laminate according to claim 1, wherein: The electric heating power density of each of the several regions separated by the electric heating film layer, the area of ​​each of the several regions separated by the electric heating film layer, the resistivity of the material of the electric heating film layer, the thickness of the electric heating film layer, and the ratio of the length to the width of each of the several regions separated by the electric heating film layer satisfy the relationship expressed by the following formula and the following conditions: Wherein, P is the electric heating power of each of the several areas separated by the electric heating film layer, in watts; S is the area of ​​each of the several areas separated by the electric heating film layer, in square meters; P / S represents the electric heating power density of each of the several areas separated by the electric heating film layer; U is the power-on voltage of the electric heating film layer, in volts; θ is the ratio of the length to the width of each of the several areas separated by the electric heating film layer; R S is the square resistance of the material of the electric heating film layer, in ohms, and R S =ρ / d, ρ is the resistivity of the material of the electric heating film layer, in ohm-meter; d is the thickness of the electric heating film layer, in meter; At -40℃, P / S is not less than 3000W / m 2 ; Preferably, when the total area of ​​the several regions separated by the electric heating film layer is 0.7-1.1m 2 When S is 0.2~0.4m 2 ; Preferably, the ratio of the length to the width of each of the several regions separated by the electric heating film layer is 1 to 2.

5.

5. The electric heating glass laminate according to claim 1 or 4, wherein: The width of the gap between the areas separated by the electric heating film layer is 0.5 to 3.5 mm, preferably 0.8 to 3.0 mm; Preferably, the thickness of the electric heating film layer is less than 100 nm, preferably less than 70 nm.

6. The electric heating glass laminate according to claim 1, wherein: The material of the electric heating film layer includes one or a combination of metal, inorganic metal oxide and graphene; Preferably, the material of the electric heating film layer includes one or a combination of Ag, ITO, FTO, AZO and graphene.

7. The electric heating glass laminate according to claim 1, wherein: The electric heating glass laminate further includes a conductive circuit connected to the electric heating film layer.

8. The electric heating glass laminate according to claim 1, wherein: The first inorganic glass plate and the second inorganic glass plate respectively include a chemically tempered glass plate, a physically tempered glass plate or a semi-tempered glass plate; Preferably, the materials of the first inorganic glass plate and the second inorganic glass plate include one or a combination of aluminosilicate glass, lithium aluminosilicate glass, borosilicate glass, boron aluminosilicate glass and soda-lime glass.

9. An electric heating glass, which comprises, from outside to inside: An outer electric heating glass layer, a first interlayer, a middle glass layer, a second interlayer and an inner glass layer; Wherein, the outer electric heating glass layer is the electric heating glass laminate according to any one of claims 1 to 8; The intermediate glass layer includes a third inorganic glass sheet; The inner glass layer includes a fourth inorganic glass plate; The outer electric heating glass layer, the first interlayer, the middle glass layer, the second interlayer and the inner glass layer are combined into a whole.

10. The electric heating glass according to claim 9, wherein: The thickness of the third inorganic glass plate is 7 to 15 mm, preferably 8 to 11 mm; Preferably, the fourth inorganic glass plate has a thickness of 4 to 12 mm, preferably 5 to 10 mm.

11. The electric heating glass according to claim 9, wherein: The third inorganic glass plate and the fourth inorganic glass plate respectively include a chemically tempered glass plate, a physically tempered glass plate or a semi-tempered glass plate; Preferably, materials of the third inorganic glass plate and the fourth inorganic glass plate include one or a combination of aluminosilicate glass, lithium aluminosilicate glass, borosilicate glass, boron aluminosilicate glass and soda-lime glass.

12. The electric heating glass according to claim 9, wherein: The thickness of the first interlayer is 2.2 to 6.0 mm, preferably 3.0 to 5.3 mm; Preferably, the thickness of the second interlayer is 1.5 to 5.3 mm, preferably 2.2 to 4.5 mm; Preferably, the materials of the first interlayer and the second interlayer respectively include one or a combination of TPU, PVB, EVA and SGP.

13. The electric heating glass according to claim 9, wherein: The shape of the electric heating glass includes a plane, a single curved surface, a double curved surface or a spherical surface.

14. The method for preparing the electrically heated glass according to any one of claims 9 to 13, comprising the following steps: S1: coating an electric heating film layer on the surface of a first inorganic glass plate, and dividing the electric heating film layer into a plurality of regions, with gaps between the regions; S2: combining the first inorganic glass plate coated with the electric heating film layer with the peripheral edge of the second inorganic glass plate and the gap between the areas of the electric heating film layer by cold laser welding to form an outer electric heating glass layer; S3: Adhere the outer electric heating glass layer, the third inorganic glass plate and the fourth inorganic glass plate together using the material of the first interlayer and the material of the second interlayer to form the first interlayer, the second interlayer, the middle glass layer and the inner glass layer, and make the first interlayer between the outer electric heating glass layer and the middle glass layer, and the second interlayer between the middle glass layer and the inner glass layer, so as to obtain the electric heating glass.

15. Use of the electric heating glass laminate according to any one of claims 1 to 8 and / or the electric heating glass according to any one of claims 9 to 13 in windshields, side windows, chord windows and escape windows; Preferably, the windshield includes an aircraft windshield, a car windshield, a rail vehicle windshield, and a windshield for ships and submersibles.

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