Methods to solve the problem of tungsten filament not conducting electricity after high-pressure treatment in electrically heated laminated glass

Abstract

This invention discloses a method for solving the problem of tungsten wires not conducting electricity in electrically heated laminated glass after high-pressure treatment, comprising the following steps: 1) Identifying the area where the non-conducting tungsten wires are located in the product and marking the position of the non-conducting tungsten wires on the product; 2) Taking a copper busbar welding template of the same specification and 1:1 size as the product, placing it on the product, drawing the copper busbars on the product, and finding the intersection of the copper busbars and the non-conducting tungsten wires on the product, which is the insulation position; 3) Preheating the insulation position first, and after reaching a certain temperature, continuing to heat and applying specific pressure to the insulation position, continuously observing the tungsten wire projection during the process until the missing tungsten wire projection reappears; then stopping heating, cooling, and releasing the pressure. By using the method described in this invention to treat partially non-conducting tungsten wires in electrically heated laminated glass, most non-compliant products can meet the requirements for factory release, effectively reducing the losses caused by the defect of non-conducting tungsten wires.

Description

Technical Field

[0001] This invention relates to laminated glass, and more specifically to a method for solving the problem of tungsten wires not conducting electricity after high-pressure treatment in electrically heated laminated glass. Background Technology

[0002] Laminated glass used in construction and vehicles is typically composed of two or more layers of tempered or ordinary glass bonded together with one or more interlayer PVB (polyvinyl butyral) films. Utilizing the adhesive properties of PVB, it resists certain impacts and penetrations, ensuring that when broken, the glass fragments remain bonded together, preventing them from scattering and injuring people. To eliminate frost, snow, or fog on the surface of laminated glass, several tungsten heating wires are typically arranged horizontally or vertically on the surface of the PVB film. The two ends of these wires converge on two copper busbars located on the PVB surface. These wires are assembled using traditional laminated glass assembly methods to form tungsten wire electrically heated laminated glass (also known as electrothermal tungsten wire laminated glass). Electrode leads from the copper busbars can be connected to an external power source; applying a certain voltage achieves the purpose of defrosting and defogging the glass.

[0003] Tungsten filament electrically heated laminated glass, based on the excellent heating properties of tungsten filaments, can help users quickly melt frost, snow, or fog on laminated glass, and is widely used in cold and extremely cold regions. Currently, tungsten filament electrically heated laminated glass commonly used in automobiles typically consists of an outer glass layer, an inner glass layer, and a PVB film placed between them. Existing methods for manufacturing tungsten filament electrically heated laminated glass generally include the following steps:

[0004] S1. Glass pretreatment: Select glass materials suitable for automotive laminated glass, and cut, grind, clean, and screen print the glass according to the designed shape and size;

[0005] S2. Glass hot bending: Pairing pre-treated glass to soften it at high temperature and form the designed surface curvature under its own weight or the action of a mold;

[0006] S3. Preparation of PVB film with wire clamping: Install copper busbars and tungsten wires onto the surface of PVB. The two copper busbars are welded to the ends of the tungsten wires to form an electrical circuit.

[0007] S4. Pre-pressing: The wire-reinforced PVB film is placed between two hot-bent glass sheets to form a sandwich structure. The resulting sandwich structure is placed in a pre-pressing furnace and pre-pressed and vacuumed at a certain temperature and pressure to initially bond the glass and film together, remove the air between the glass and film and seal the surrounding area, while ensuring that there is no misalignment between the layers.

[0008] S5. High pressure: The laminated glass obtained after pre-compression treatment is placed in an autoclave and heated and pressed at higher temperatures and pressures, so that the residual air between the two glass panes dissolves in the PVB material and the gap between the glass panes is filled by the fluidity of the melted PVB.

[0009] A typical piece of tungsten filament electrically heated laminated glass contains approximately 250 to 700 tungsten filaments. Original equipment manufacturers (OEMs) require that no single filament be non-energized. Our team discovered during the production process that even when using laminated glass samples where all filaments are properly energized after pre-pressing, a 10-15% proportion of the final product still exhibits filament failure (non-energization) after high-pressure processing. This defect results in a 10-15% loss of these products, leading to a low yield. Furthermore, given the high manufacturing cost of this type of laminated glass (2-3 times higher than ordinary laminated glass), this defect also represents a significant waste. Currently, there is a lack of an efficient, precise, and reliable method to address this problem. Summary of the Invention

[0010] The technical problem to be solved by the present invention is to provide a method for solving the problem of tungsten wires not being energized after high-pressure treatment of electrically heated laminated glass. By using this method to treat some of the tungsten wires that are not energized in electrically heated laminated glass, most of the non-compliant products can meet the requirements for leaving the factory, effectively reducing the losses caused by the defect of tungsten wires not being energized.

[0011] The inventors of this application, after disassembling and studying samples exhibiting a high proportion (10-15% of the resulting products) of partial tungsten filament non-conductivity defects after high-pressure processing, concluded that the cause of this defect is as follows: During high-pressure processing, PVB melts at high temperatures and possesses a certain degree of fluidity. It automatically flows to fill the gaps between the two hot-bent glass sheets. If there are welding defects in the copper busbars, gaps may also exist between the two busbars. The molten PVB may then flow into these gaps, encasing the tungsten filament and causing it to lose conductivity, i.e., resulting in insulation defects. After extensive experimental research, the inventors of this application propose a method to repair products with this partial tungsten filament insulation defect, thus meeting the original factory requirements for tungsten filament electrically heated laminated glass components. The specific method is as follows:

[0012] A method to solve the problem of tungsten filaments not conducting electricity after high-pressure processing in electrically heated laminated glass includes the following steps:

[0013] 1) Power on the product and use the projection principle to identify the areas where the non-powered tungsten wires are located. Mark the positions of the non-powered tungsten wires in the areas where the non-powered tungsten wires are located on the product according to the design requirements of the spacing between adjacent tungsten wires.

[0014] 2) Take a copper busbar welding template of the same specification as the product and 1:1 size as the product, place it on the product, draw the copper busbar on the product, and find the intersection of the copper busbar on the product and the non-energized tungsten wire, which is the insulation position.

[0015] 3) Preheat the insulation position. When the temperature of the insulation position reaches 100-120℃, continue heating the insulation position while applying a pressure of 60-100N. During the process, continuously observe the tungsten filament projection until the missing tungsten filament projection reappears. Then stop heating the insulation position and cool it down. When the temperature of the insulation position is lower than or equal to 40℃, release the pressure applied to the insulation position.

[0016] The product involved in the method described in this invention is tungsten wire electrically heated laminated glass that does not meet the original factory requirements for parts and has some tungsten wires that are not energized.

[0017] In step 1) of the above preparation method, identifying the area where the non-energized tungsten filament is located in the product using the projection principle after the product is powered on is a conventional technique. Specifically, the product is fixed on a bracket, the tungsten filament in the product is powered on, and the product is irradiated with a white light source (there is a certain relationship between temperature and refractive index; generally, as the temperature increases, the refractive index also changes. According to the definition of the coefficient of thermal expansion, when a material is heated, due to the enhancement of molecular vibration, the volume of the material will expand, causing a change in the refractive index), so that it produces a clear shadow on a white background wall (i.e., the tungsten filament projection). That is to say, a tungsten filament projection appears on the white background wall. The location with abnormal tungsten filament projection spacing is found. Since the tungsten filament is not powered and heated at this location, the refractive index of the light is different from that of other tungsten filament locations, so no clear tungsten filament projection appears. Therefore, the location with abnormal tungsten filament projection spacing is determined to be the area where the non-energized tungsten filament is located. For products of different specifications, there are certain design requirements for the spacing between two adjacent tungsten wires. After finding the area where the non-energized tungsten wire is located, mark the position of the non-energized tungsten wire in the area of ​​the product according to the design requirements for the spacing between two tungsten wires.

[0018] In step 2) of the above preparation method, when placing the copper busbar welding template on the product, the glass outline edge of the copper busbar welding template is required to be aligned with the edge of the product and stacked together. Then, the corresponding position of the copper busbar on the product is drawn according to the position of the copper busbar on the copper busbar welding template.

[0019] In step 3) of the above preparation method, a hot air gun is typically used to preheat the insulating area. While continuing to heat the insulating area, the temperature of the heated region (i.e., the insulating area or adjacent to the insulating area) is controlled to be below or equal to 140°C. During preheating or heating, an infrared thermometer is typically used to detect the temperature of the heated area. The applicant found in experiments that a preheating temperature of 100–120°C is just right for sufficiently softening the PVB film and giving it a certain degree of fluidity. Temperatures that are too low cannot guarantee sufficient softening of the PVB, while temperatures that are too high will damage the PVB structure or cause bubble problems.

[0020] In step 3) of the above preparation method, this application specifically applies pressure to the insulation location by installing a clamp at the insulation position and adjusting the clamping tightness of the clamp. In this step, the applicant found in experiments that a pressure of 60-100N is suitable. Too low a pressure cannot guarantee that PVB will be extruded between the tungsten wire and the copper busbar and is prone to causing air bubbles, while too high a pressure can easily crack the glass. When applying pressure to the insulation location, it is usually done by gradually increasing the pressure from the lowest possible level, such as applying 60N initially. During this process, the tungsten wire projection is observed. If the missing tungsten wire projection at the abnormal spacing position does not reappear, the applied pressure is increased and the tungsten wire projection is observed until the missing tungsten wire projection reappears. If the missing tungsten wire projection is not observed to reappear even when the applied pressure is increased to 100N and heating is maintained, the applied pressure should not be increased further to avoid cracking the glass due to excessive pressure. On the other hand, the fact that the missing tungsten filament projection did not reappear even when the pressure was increased to 100N and heating was maintained suggests that the defect of the tungsten filament not being energized may be caused by other reasons.

[0021] In step 3) of the above preparation method, after stopping heating of the insulating position, the laminated glass or insulating position needs to be cooled to avoid sudden cooling cracking. Cooling also allows the molten PVB to return to a solid state, ensuring it adheres firmly to the glass. This can be achieved through natural cooling or by spraying ethanol onto the product to cool the insulating position. The concentration of the ethanol is typically 30–100 v / v%. Usually, the pressure applied to the insulating position is removed when the temperature is below or equal to 40°C. At this point, the PVB has solidified, preventing the PVB from flowing back and encapsulating the tungsten wire after pressure relief.

[0022] Compared with existing technologies, this invention proposes a method for repairing tungsten wire electrically heated laminated glass products with partial tungsten wire insulation defects, so that the defective products can meet the original factory requirements for tungsten wire electrically heated laminated glass parts. After processing the tungsten wire electrically heated laminated glass products with partial tungsten wire insulation defects using the method described in this invention, more than 90% of the aforementioned defective products can meet the original factory requirements for parts, significantly reducing the losses of manufacturing enterprises and significantly reducing production costs. Attached Figure Description

[0023] Figure 1 These are projection photos of the product before and after the tungsten filament is energized in the method described in this invention, where (a) is before the tungsten filament is energized and (b) is after the tungsten filament is energized.

[0024] Figure 2 This is a schematic diagram of a product where the non-energized tungsten filament is located using the method described in this invention.

[0025] Figure 3 This is a schematic diagram of a product in which the location of the non-energized tungsten filament is marked in the area where the tungsten filament is located, as described in the method of the present invention.

[0026] Figure 4 This is a schematic diagram of a product with the insulation positions marked in the method described in this invention.

[0027] Figure 5 This is a schematic diagram of tungsten wire electrically heated laminated glass that meets the original manufacturer's requirements after processing a product with a partial tungsten wire non-conductivity defect using the method described in this invention. Detailed Implementation

[0028] To better explain the technical solution of the present invention, the present invention will be further described in detail below with reference to the embodiments, but the implementation of the present invention is not limited thereto.

[0029] Example 1

[0030] One hundred pieces of tungsten wire electrically heated laminated glass, model NS08ACUBH series (the spacing between two adjacent tungsten wires in this product is 3.06±0.14mm), manufactured by the applicant for automotive windshields, were collected. These pieces, after manual inspection, were found to have defects where some tungsten wires were not conducting electricity. The collected products were repaired according to the following steps to resolve these defects:

[0031] 1) Fix the product on the bracket, electrify the tungsten filament in the product, and illuminate the product with a white light source. A clear shadow will appear on a white background wall (this is the tungsten filament projection). Images of the product's projection before and after electrification are shown below. Figure 1As shown, the locations with abnormal tungsten filament projection spacing are identified as the areas where non-energized tungsten filaments are located. Figure 2 As shown. Based on the design requirements for the spacing between adjacent tungsten filaments in the product, mark the positions of the non-energized tungsten filaments in the areas where non-energized tungsten filaments are located on the product, such as... Figure 3 As shown.

[0032] 2) With the tungsten filament energized, take a copper busbar welding template of the same specifications and 1:1 size as the product. Place the copper busbar welding template on the product, ensuring the glass outline edge of the template aligns with the edge of the product, and stack them together. Then, based on the position of the copper busbars (there are two copper busbars) on the template, draw the corresponding position of the copper busbars on the product. Find the intersection of the copper busbars on the product and the unenergized tungsten filament; this is the insulation position (e.g., ...). Figure 4 As shown in the diagram, the two black dots indicate the insulation positions.

[0033] 3) With the tungsten filament energized, preheat the insulation area using an adjustable-temperature hot air gun. Use an infrared thermometer to detect the temperature of the heated area. When the temperature of the insulation area reaches 110-120℃, continue heating the insulation area with the adjustable-temperature hot air gun while simultaneously installing a clamp at the insulation area (the clamp is a G-type clamp, manufacturer: Zhejiang Niuxiang Hardware Tools Co., Ltd., model: 4-6 inches; add a flexible thin-film pressure sensor (manufacturer: Changzhou Rouxi Electronic Technology Co., Ltd., model: RX-D12020KG specification) to one end of the clamp to measure the screw stroke of the G-type clamp reaching 60-100N). Apply 60-100N of pressure to the insulation area by adjusting the clamping tightness, gradually increasing the pressure from low to high in increments of 10N. Throughout the process, control the temperature of the insulation area to not exceed 140℃ (otherwise, it will cause PVB burning or bubbling problems), and continuously observe the tungsten filament projection until the missing tungsten filament projection reappears (e.g., Figure 5 (As shown), then stop heating the insulation area. On the other hand, if the missing tungsten filament projection is not observed to reappear even when the pressure is adjusted to 100N and heating is maintained, stop heating the insulation area as well. After stopping heating the insulation area, spray 80v / v% ethanol onto the product to cool it, while simultaneously restoring the molten PVB to a solid state, allowing it to bond with the glass. When the temperature of the insulation area is below or equal to 40°C, release the pressure applied to the insulation area.

[0034] After processing 100 pieces of tungsten-wire electrically heated laminated glass with partial tungsten filament non-conductivity, 98 pieces of tungsten-wire electrically heated laminated glass with partial tungsten filament non-conductivity achieved full tungsten filament conductivity. It is evident that the method described in this invention can effectively repair the defect of partial tungsten filament non-conductivity. Applying it to actual production can significantly reduce losses for manufacturing enterprises and lower production costs.

Claims

1. A method to solve the problem of tungsten filaments not conducting electricity after high-pressure processing in electrically heated laminated glass includes the following steps: 1) Power on the product and use the projection principle to identify the areas where the non-powered tungsten wires are located. Mark the positions of the non-powered tungsten wires in the areas where the non-powered tungsten wires are located on the product according to the design requirements of the spacing between adjacent tungsten wires. 2) Take a copper busbar welding template of the same specification as the product and 1:1 size as the product, place it on the product, draw the copper busbar on the product, and find the intersection of the copper busbar on the product and the non-energized tungsten wire, which is the insulation position. 3) Preheat the insulation position. When the temperature of the insulation position reaches 100-120℃, continue heating the insulation position while applying a pressure of 60-100N. During the process, continuously observe the tungsten filament projection until the missing tungsten filament projection reappears. Then stop heating the insulation position and cool it down. When the temperature of the insulation position is lower than or equal to 40℃, release the pressure applied to the insulation position.

2. The method according to claim 1, characterized in that, In step 3), when continuing to heat the insulated area, the temperature of the heated area is controlled to be below or equal to 140°C.

3. The method according to claim 1, characterized in that, In step 3), pressure is applied to the insulation location by installing a clamp at the insulation location and adjusting the clamping degree of the clamp.

4. The method according to claim 1, characterized in that, In step 3), the insulation area is cooled by spraying ethanol onto the product.

5. The method according to claim 4, characterized in that, In step 3), the concentration of ethanol is 30–100 v / v.

6. The method according to any one of claims 1 to 5, characterized in that, The product is a tungsten wire electrically heated laminated glass in which some tungsten wires are not energized.

Images