A method for selective laser welding of electric field composite glass and metal

Abstract

This invention relates to a method for selective laser welding of glass and metal using an electric field composite, comprising the following steps: S1, a ceramic insulating sheet, an anode electrode plate, a metal substrate, a glass substrate, and a cathode electrode plate are sequentially clamped from bottom to top, and the anode and cathode electrode plates are electrically connected to a power source. The electric field device and a current-voltage recorder are turned on to complete sample assembly; S2, the laser focus is positioned above the cathode electrode plate, with the focus point defocused relative to the interface between the metal and glass substrates. Based on a predetermined scanning path, laser welding is completed on the focal plane; S3, after scanning, the current drops to 0 mA, the electric field is turned off, and the surface is allowed to cool naturally to obtain a welded joint. This invention successfully achieves high-quality selective laser welding of glass and metal using an electric field composite continuous laser, significantly reducing the temperature and welding time required during laser welding, and effectively solving the problem of glass substrate cracking caused by excessive thermal stress in traditional laser welding.

Description

Technical Field

[0001] This invention relates to the field of laser processing technology, and in particular to a method for continuous laser selective welding of electric field composite glass and metal. Background Technology

[0002] Glass substrates, due to their high light transmittance, excellent electrical insulation, strong chemical stability, strong weather resistance, low dielectric loss, and high-frequency adaptability, are widely used in various scenarios. Metals, with their high mechanical strength, excellent thermal and electrical conductivity, and adjustable coefficient of thermal expansion, can provide crucial structural support and functional integration for dissimilar material connectors. Glass substrates and metals achieve functional complementarity through dissimilar material welding, making them irreplaceable in fields such as aerospace, photovoltaic power generation, electronic packaging, and microelectromechanical systems (MEMS) packaging manufacturing.

[0003] Currently, methods for joining dissimilar materials such as glass substrates and metals include adhesive bonding, brazing, mechanical riveting, anodic bonding, matching encapsulation, and laser welding. However, even with significant advancements in joining technologies, several problems remain, such as physicochemical incompatibilities related to atomic bond structure, coefficient of linear expansion, thermal conductivity, and plasticity, as well as residual thermal stress. This leads to interfacial wetting and spreading issues, interfacial reactions, and joint stress problems between the glass substrate and the metal. Particularly during laser welding, the glass substrate and metal need to be above the softening temperature of the glass substrate to allow the metal-glass mixture to fill the gap between them, thus achieving a connection. This method is suitable for quartz glass substrates with good thermal shock resistance. However, when welding common glass substrates such as soda-lime glass and aluminosilicate glass substrates with poor thermal shock resistance, the excessive thermal stress generated by the laser can cause joint defects, such as cracking of the glass substrate, interfacial cavities, and voids. This reduces the quality of the joint and hinders the widespread application of laser joining technology in industry.

[0004] Chinese Patent Application No. CN118951202B, recently filed by the applicant, discloses a method for laser welding a glass substrate to a metal using a double-layer brazing filler metal. The method includes the following steps: Step 1: Surface pretreatment; ultrasonically cleaning the surfaces of both the metal and glass substrates; sequentially depositing nano-Si and Al double-layer pre-placed brazing filler metal on the glass substrate surface using pulsed laser deposition technology in the area to be welded; Step 2: Sample assembly; assembling the glass substrate and metal according to the requirements of the connection joint; placing the glass substrate with the pre-placed brazing filler metal facing down on the metal, and clamping both together using a fixture; Step 3: Nanosecond laser welding; focusing the laser on the contact surface between the thin-film brazing filler metal and the glass substrate, ensuring the focal points are on the same plane; scanning and welding on the focal plane; Step 4: Post-weld treatment; performing post-weld heat treatment using a high-frequency nanosecond laser, followed by natural cooling of the joint.

[0005] The existing technical solutions described above have the following drawbacks: First, the preparation process of the double-layer thin-film solder is relatively complex. Pulsed laser deposition technology has high equipment requirements and requires the sequential deposition of nano-Si and Al thin films, resulting in numerous process steps and long processing times, which is not conducive to industrial mass production. Second, during nanosecond laser welding, the focus needs to be precisely controlled on the contact surface between the thin-film solder and the glass substrate and kept scanning on the same plane, which places stringent requirements on the motion accuracy and positioning system of the equipment, increasing the difficulty of operation and production costs. In addition, high-frequency nanosecond laser heat treatment is required after welding, which further prolongs the production cycle. Moreover, the additional laser treatment process may have uncontrollable effects on the joint structure and performance. For example, overheating may lead to excessive diffusion of solder elements or secondary damage to the glass substrate. At the same time, this method mainly relies on the pre-placed double-layer solder to alleviate thermal stress. For glass substrates and metal combinations with greater differences in thermal expansion coefficients, the stress relief effect may be limited, and it is still difficult to completely avoid defects such as cracking caused by thermal stress concentration in ordinary glass substrates during welding. Summary of the Invention

[0006] The problem this invention aims to solve is to address the aforementioned shortcomings of existing technologies by providing a continuous laser selective welding method for glass and metal using an electric field composite. This method employs continuous laser selective welding while simultaneously coupling a uniform electric field perpendicular to the sample. A strong electrostatic attraction is generated at the interface. As the laser penetrates the glass substrate and reaches the metal substrate surface, the metal substrate absorbs the laser energy, causing the interface to polarize under the combined action of the laser and the electric field. This promotes the migration of alkali metal ions away from the interface. Under the action of the laser, oxygen anions are left at the interface, causing anodizing and solid-phase reactions in the metal, achieving selective bonding between the glass substrate and the metal. After employing electric field composite continuous laser welding, the electric field force at the interface reduces the gap between the glass and metal substrates, overcoming the limitation of requiring optical contact in laser welding and lowering the originally stringent assembly requirements. This is expected to promote industrial applications. Simultaneously, since the polarization of the glass substrate can occur below its chemical transition temperature, this significantly reduces the bonding temperature of the glass-metal laser welding, suppressing interface defects caused by excessive thermal stress generated by the laser, such as glass substrate cracking, interface cavities, and holes, further improving the welding quality of the joint.

[0007] The above-mentioned objective of this invention is achieved through the following technical solutions:

[0008] A method for selective laser welding of electric field composite glass and metal includes the following steps:

[0009] S1 sequentially clamps a ceramic insulating sheet, an anode electrode plate, a metal substrate, a glass substrate, and a cathode electrode plate from bottom to top, and electrically connects the anode electrode plate and the cathode electrode plate to the power supply respectively. Then, the electric field device and the current and voltage recorder are turned on to complete the sample assembly.

[0010] S2 places the laser focus above the cathode electrode plate, and the focus is defocused relative to the interface between the metal substrate and the glass substrate. Based on a predetermined scanning path, the laser welding on the focal plane is completed.

[0011] After the S3 scan is completed, wait for the current to drop to 0mA, turn off the electric field, and allow it to cool naturally to obtain the welded joint.

[0012] Furthermore, in S1, the ceramic insulating sheet, anode electrode plate, metal substrate, glass substrate and cathode electrode plate are ultrasonically cleaned with alcohol and acetone respectively, and then dried.

[0013] Further, in step S1, the anode electrode plate and the cathode electrode plate are respectively on the same plane as the outer surfaces of the metal substrate and the glass substrate, or are spaced apart. The side lengths of the anode electrode plate and the cathode electrode plate should be equal to or slightly smaller than the side lengths of the metal substrate and the glass substrate.

[0014] Furthermore, in S1, the anode electrode plate is made of one of the following materials: titanium alloy plate, stainless steel plate, and copper plate.

[0015] Furthermore, in S1, the metal substrate is made of one of the following materials: pure aluminum foil, pure copper foil, stainless steel foil, and Kovar alloy plate.

[0016] Furthermore, in step S1, the glass substrate is made of electrolyte glass. Preferably, it is an alkali metal ion glass substrate.

[0017] Furthermore, in S1, the cathode electrode plate is made of either ITO conductive glass substrate or FTO conductive glass substrate.

[0018] Furthermore, in S1, the electric field of the control power supply is a constant voltage steady-state electric field with a voltage of 300~600V and a dielectric strength of 240~480V / mm. The direction of the electric field is from the anode electrode plate to the cathode electrode plate, and remains the same in the regions of the anode electrode plate and the cathode electrode plate, and is perpendicular to the metal substrate and the glass substrate. The electric field type is one of direct current, alternating current and pulse current.

[0019] Furthermore, in S2, the scanning path is one or a combination of several of the following: line-by-line scanning path, bow-shaped scanning path, grid-interwoven scanning path, concentric circle scanning path, and spiral scanning path.

[0020] Furthermore, in S2, the laser energy distribution is controlled to be a near-flat-top spot, the focal distance is 90~100mm from the upper surface of the cathode electrode plate, the spot size is 4~8mm, the laser power is 80~800W, and the welding speed is 1~20mm / s.

[0021] Furthermore, in S2, the laser welding environment is an air environment and no shielding gas is required.

[0022] In summary, the beneficial technical effects of this invention are as follows: The joint strength achieved by the electric field composite glass and metal continuous laser selective welding method is 16.2~28.1 MPa. This method overcomes the limitation of laser welding requiring optical contact, reducing the originally stringent assembly requirements. Furthermore, welding can occur below the glass substrate's thermal transition temperature, significantly lowering the connection temperature between the glass substrate and the metal in laser welding. This helps suppress interface defects caused by excessive thermal stress generated by the laser, such as glass substrate cracking, interface cavities, and holes, further improving the welding quality of the joint, especially for welding glass substrates with poor thermal shock resistance to metal. Attached Figure Description

[0023] Figure 1 This is a flowchart of the method provided in Embodiment 1 of the present invention.

[0024] Figure 2 This is a diagram of the bow-shaped scanning path in Embodiment 1 of the present invention.

[0025] Figure 3 This is a schematic diagram showing the connection relationship between the ceramic insulating sheet, the anode electrode plate, the metal substrate, the glass substrate, and the cathode electrode plate in Embodiment 1 of the present invention.

[0026] Figure 4 This is an electron microscope image of the interface between the metal substrate and the glass substrate welded joint obtained in Embodiment 1 of the present invention.

[0027] Figure 5 This is a time and current curve of the metal substrate and glass substrate during the laser welding process in Embodiment 1 of the present invention.

[0028] Figure 6 This is an electron microscope image of the interface between the metal substrate and the glass substrate welded joint obtained in Embodiment 2 of the present invention.

[0029] Figure 7 This is a time and current curve of the metal substrate and glass substrate during the laser welding process in Embodiment 2 of the present invention.

[0030] Figure 8 This is an electron microscope image of the interface between the metal substrate and the glass substrate welded joint obtained in Embodiment 3 of the present invention.

[0031] Figure 9 This is a time and current curve of the metal substrate and glass substrate during the laser welding process in Embodiment 3 of the present invention.

[0032] Figure 10 This is an electron microscope image of the interface between the metal substrate and the glass substrate welded joint obtained in Comparative Example 2 of the present invention. Detailed Implementation

[0033] To make the technical means, creative features, objectives and effects of this invention clearer and easier to understand, the invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0034] Example 1: A method for selective laser welding of electric field composite glass and metal according to the present invention includes the following steps:

[0035] S1 Surface Pretreatment: The surfaces of the 15μm thick metal substrate (aluminum foil), 1.05mm thick glass substrate (Corning 5318 glass substrate), cathode electrode plate (ITO glass substrate), anode electrode plate (copper plate) and ceramic insulating sheet are ultrasonically cleaned with alcohol and acetone and then dried. The side lengths of the anode electrode plate and cathode electrode plate should be equal to or slightly smaller than the side lengths of the metal substrate and glass substrate.

[0036] S2 Sample Assembly: Place the metal substrate and glass substrate to be welded between the anode electrode plate and the cathode electrode plate. Place a ceramic insulating plate at the bottom. Clamp the ceramic insulating sheet, anode electrode plate, metal substrate, glass substrate and cathode electrode plate in sequence from bottom to top. Clamp the sample with a clamp. Connect the anode electrode plate to the positive terminal of the external power supply and the cathode electrode plate to the cathode terminal of the external power supply. The electric field is a constant voltage steady-state electric field with a voltage of 400V and a dielectric strength of 320V / mm. The direction of the electric field is from the anode electrode plate to the cathode electrode plate. It is the same in the area of ​​the anode electrode plate and the cathode electrode plate and is perpendicular to the metal substrate and the glass substrate. The electric field type is pulse current. Turn on the electric field device and the current and voltage recorder.

[0037] S3 electric field composite continuous laser welding: The laser focus is arranged above the cathode electrode plate, and the focus is defocused relative to the interface between the metal substrate and the glass substrate. Based on the predetermined bow-shaped scanning path, the laser welding on the focal plane is completed, and the laser energy distribution is controlled to be a near-flat top spot. The focal distance is 90mm from the upper surface of the cathode electrode plate, the spot size is 6mm, the laser power is 90W, the welding speed is 5mm / s, the welding trajectory is a straight line, and the laser welding environment is an air environment and no shielding gas is required.

[0038] S4 Welding Completed: After scanning is complete, wait for the current to drop to 0mA, turn off the electric field, and allow it to cool naturally to obtain the welded joint.

[0039] The electron microscope image of the interface between the metal substrate and the glass substrate welded joint obtained in this embodiment is shown below. Figure 4 As shown, by observation Figure 4 It can be observed that the interface between the metal substrate and the glass substrate using the electric field composite glass-metal continuous laser selective welding method is smooth and continuous, with no obvious molten pool, indicating that solid-state bonding between the two has been achieved. The time-current curves are shown below. Figure 5 As shown, the current in the circuit indicates that sodium ions in the electrolyte glass migrate towards the cathode under the influence of an electric field and continuous laser light. Testing revealed that the room temperature shear strength of the welded joint between the metal substrate and the glass substrate prepared in this embodiment reached 28.1 MPa.

[0040] Example 2: A method for selective laser welding of electric field composite glass and metal according to the present invention includes the following steps:

[0041] S1 Surface Pretreatment: The surfaces of the 15μm thick metal substrate (aluminum foil), 1.05mm thick glass substrate (Corning 5318 glass substrate), cathode electrode plate (ITO glass substrate), anode electrode plate (copper plate) and ceramic insulating sheet are ultrasonically cleaned with alcohol and acetone and then dried.

[0042] S2 Sample Assembly: Place the metal substrate and glass substrate to be welded between the anode electrode plate and the cathode electrode plate. Place a ceramic insulating plate at the bottom. Clamp the ceramic insulating sheet, anode electrode plate, metal substrate, glass substrate and cathode electrode plate in sequence from bottom to top. Clamp the sample with a clamp. Connect the anode electrode plate to the positive terminal of the external power supply and the cathode electrode plate to the cathode terminal of the external power supply. The electric field is a constant voltage steady-state electric field with a voltage of 300V and a dielectric strength of 240V / mm. The direction of the electric field is from the anode electrode plate to the cathode electrode plate. It is the same in the area of ​​the anode electrode plate and the cathode electrode plate and is perpendicular to the metal substrate and the glass substrate. The electric field type is pulse current. Turn on the electric field device and the current and voltage recorder.

[0043] S3 electric field composite continuous laser welding: The laser focus is arranged above the cathode electrode plate, and the focus is defocused relative to the interface between the metal substrate and the glass substrate. Based on the predetermined bow-shaped scanning path, the laser welding on the focal plane is completed, and the laser energy distribution is controlled to be a near-flat top spot. The focal distance is 90mm from the upper surface of the cathode electrode plate, the spot size is 6mm, the laser power is 90W, the welding speed is 5mm / s, the welding trajectory is a straight line, and the laser welding environment is an air environment and no shielding gas is required.

[0044] S4 Welding Completed: After scanning is complete, wait for the current to drop to 0mA, turn off the electric field, and allow it to cool naturally to obtain the welded joint.

[0045] The electron microscope image of the interface between the metal substrate and the glass substrate welded joint obtained in this embodiment is shown below. Figure 6 As shown, by observation Figure 6 It can be observed that the interface between the metal substrate and the glass substrate using the electric field composite glass-metal continuous laser selective welding method is smooth and continuous, with no obvious molten pool, indicating that solid-state bonding between the two has been achieved. The time-current curves are shown below. Figure 7 As shown, the current in the circuit indicates that sodium ions in the electrolyte glass migrate towards the cathode under the influence of an electric field and continuous laser light. Testing revealed that the room temperature shear strength of the welded joint between the metal substrate and the glass substrate prepared in this embodiment reached 22 MPa.

[0046] Example 3: A method for continuous laser selective welding of electric field composite glass and metal disclosed in this invention includes the following steps:

[0047] S1 Surface Pretreatment: The surfaces of the 15μm thick metal substrate (aluminum foil), 1.05mm thick glass substrate (Corning 5318 glass substrate), cathode electrode plate (ITO glass substrate), anode electrode plate (copper plate) and ceramic insulating sheet are ultrasonically cleaned with alcohol and acetone and then dried.

[0048] S2 Sample Assembly: Place the metal substrate and glass substrate to be welded between the anode electrode plate and the cathode electrode plate. Place a ceramic insulating plate at the bottom. Clamp the ceramic insulating sheet, anode electrode plate, metal substrate, glass substrate and cathode electrode plate in sequence from bottom to top. Clamp the sample with a clamp. Connect the anode electrode plate to the positive terminal of the external power supply and the cathode electrode plate to the cathode terminal of the external power supply. The electric field is a constant voltage steady-state electric field with a voltage of 500V and a dielectric strength of 400V / mm. The direction of the electric field is from the anode electrode plate to the cathode electrode plate. It is the same in the area of ​​the anode electrode plate and the cathode electrode plate and is perpendicular to the metal substrate and the glass substrate. The electric field type is pulse current. Turn on the electric field device and the current and voltage recorder.

[0049] S3 electric field composite continuous laser welding: The laser focus is arranged above the cathode electrode plate, and the focus is defocused relative to the interface between the metal substrate and the glass substrate. Based on the predetermined bow-shaped scanning path, the laser welding on the focal plane is completed, and the laser energy distribution is controlled to be a near-flat top spot. The focal distance is 90mm from the upper surface of the cathode electrode plate, the spot size is 6mm, the laser power is 90W, the welding speed is 5mm / s, the welding trajectory is a straight line, and the laser welding environment is an air environment and no shielding gas is required.

[0050] S4 Welding Completed: After scanning is complete, wait for the current to drop to 0mA, turn off the electric field, and allow it to cool naturally to obtain the welded joint.

[0051] The electron microscope image of the interface between the metal substrate and the glass substrate welded joint obtained in this embodiment is shown below. Figure 8 As shown, by observation Figure 8It can be observed that the interface between the metal substrate and the glass substrate using the electric field composite glass-metal continuous laser selective welding method is smooth and continuous, with no obvious molten pool, indicating that solid-state bonding between the two has been achieved. The time-current curves are shown below. Figure 9 As shown, the current in the circuit indicates that sodium ions in the electrolyte glass migrate towards the cathode under the influence of an electric field and continuous laser light. Testing revealed that the room temperature shear strength of the welded joint between the metal substrate and the glass substrate prepared in this embodiment reached 18.3 MPa.

[0052] Example 4: A continuous laser selective welding method for electric field composite glass and metal disclosed in this invention includes the following steps:

[0053] S1 Surface Pretreatment: The surfaces of the 15μm thick metal substrate (aluminum foil), 1mm thick glass substrate (sodium-calcium glass substrate), cathode electrode plate (ITO glass substrate), anode electrode plate (copper plate) and ceramic insulating sheet are ultrasonically cleaned with alcohol and acetone and then dried.

[0054] S2 Sample Assembly: Place the metal substrate and glass substrate to be welded between the anode electrode plate and the cathode electrode plate. Place a ceramic insulating plate at the bottom. Clamp the ceramic insulating sheet, anode electrode plate, metal substrate, glass substrate and cathode electrode plate in sequence from bottom to top. Clamp the sample with a clamp. Connect the anode electrode plate to the positive terminal of the external power supply and the cathode electrode plate to the cathode terminal of the external power supply. The electric field is a constant voltage steady-state electric field with a voltage of 400V and a dielectric strength of 320V / mm. The direction of the electric field is from the anode electrode plate to the cathode electrode plate. It is the same in the area of ​​the anode electrode plate and the cathode electrode plate and is perpendicular to the metal substrate and the glass substrate. The electric field type is pulse current. Turn on the electric field device and the current and voltage recorder.

[0055] S3 electric field composite continuous laser welding: The laser focus is arranged above the cathode electrode plate, and the focus is defocused relative to the interface between the metal substrate and the glass substrate. Based on the predetermined bow-shaped scanning path, the laser welding on the focal plane is completed, and the laser energy distribution is controlled to be a near-flat top spot. The focal distance is 100mm from the upper surface of the cathode electrode plate, the spot size is 6mm, the laser power is 120W, the welding speed is 20mm / s, the welding trajectory is a straight line, and the laser welding environment is an air environment and no shielding gas is required.

[0056] S4 Welding Completed: After scanning is complete, wait for the current to drop to 0mA, turn off the electric field, and allow it to cool naturally to obtain the welded joint.

[0057] The welded joint between the metal substrate and the glass substrate prepared in this embodiment has a smooth and continuous interface without a significant molten pool, indicating that a solid-state bond has been achieved. The transient current in the circuit indicates that sodium ions in the electrolyte glass migrate towards the cathode under the action of the electric field and continuous laser. Testing showed that the room temperature shear strength of the welded joint between the metal substrate and the glass substrate prepared in this embodiment reached 16.2 MPa.

[0058] Example 5: A method for continuous laser selective welding of electric field composite glass and metal disclosed in this invention includes the following steps:

[0059] S1 Surface Pretreatment: The surfaces of the 15μm thick metal substrate (aluminum foil), 0.2mm thick glass substrate (sodium-calcium glass substrate), cathode electrode plate (ITO glass substrate), anode electrode plate (copper plate) and ceramic insulating sheet are ultrasonically cleaned with alcohol and acetone and then dried.

[0060] S2 Sample Assembly: Place the metal substrate and glass substrate to be welded between the anode electrode plate and the cathode electrode plate. Place a ceramic insulating plate at the bottom. Clamp the ceramic insulating sheet, anode electrode plate, metal substrate, glass substrate and cathode electrode plate in sequence from bottom to top. Clamp the sample with a clamp. Connect the anode electrode plate to the positive terminal of the external power supply and the cathode electrode plate to the cathode terminal of the external power supply. The electric field is a constant voltage steady-state electric field with a voltage of 400V and a dielectric strength of 320V / mm. The direction of the electric field is from the anode electrode plate to the cathode electrode plate. It is the same in the area of ​​the anode electrode plate and the cathode electrode plate and is perpendicular to the metal substrate and the glass substrate. The electric field type is pulse current. Turn on the electric field device and the current and voltage recorder.

[0061] S3 electric field composite continuous laser welding: The laser focus is placed above the cathode electrode plate, and the focus is defocused relative to the interface between the metal substrate and the glass substrate. Based on the predetermined bow-shaped scanning path, the laser welding on the focal plane is completed, and the laser energy distribution is controlled to be a near-flat top spot. The focal distance is 90mm from the upper surface of the cathode electrode plate, the spot size is 6mm, the laser power is 100W, the welding speed is 5mm / s, the welding trajectory is a straight line, and the laser welding environment is an air environment and no shielding gas is required.

[0062] S4 Welding Completed: After scanning is complete, wait for the current to drop to 0mA, turn off the electric field, and allow it to cool naturally to obtain the welded joint.

[0063] The welded joint between the metal substrate and the glass substrate prepared in this embodiment has a smooth and continuous interface without a significant molten pool, indicating that a solid-state bond has been achieved. The transient current in the circuit indicates that sodium ions in the electrolyte glass migrate towards the cathode under the action of the electric field and continuous laser. Testing showed that the room temperature shear strength of the welded joint between the metal substrate and the glass substrate prepared in this embodiment reached 16.2 MPa.

[0064] Example 6: A method for continuous laser selective welding of electric field composite glass and metal disclosed in this invention includes the following steps:

[0065] S1 Surface Pretreatment: The surfaces of the 15μm thick metal substrate (copper foil), 1mm thick glass substrate (sodium calcium glass substrate), cathode electrode plate (ITO glass substrate), anode electrode plate (copper plate) and ceramic insulating sheet are ultrasonically cleaned with alcohol and acetone and then dried.

[0066] S2 Sample Assembly: Place the metal substrate and glass substrate to be welded between the anode electrode plate and the cathode electrode plate. Place a ceramic insulating plate at the bottom. Clamp the ceramic insulating sheet, anode electrode plate, metal substrate, glass substrate and cathode electrode plate in sequence from bottom to top. Clamp the sample with a clamp. Connect the anode electrode plate to the positive terminal of the external power supply and the cathode electrode plate to the cathode terminal of the external power supply. The electric field is a constant voltage steady-state electric field with a voltage of 400V and a dielectric strength of 320V / mm. The direction of the electric field is from the anode electrode plate to the cathode electrode plate. It is the same in the area of ​​the anode electrode plate and the cathode electrode plate and is perpendicular to the metal substrate and the glass substrate. The electric field type is pulse current. Turn on the electric field device and the current and voltage recorder.

[0067] S3 electric field composite continuous laser welding: The laser focus is placed above the cathode electrode plate, and the focus is defocused relative to the interface between the metal substrate and the glass substrate. Based on the predetermined bow-shaped scanning path, the laser welding on the focal plane is completed, and the laser energy distribution is controlled to be a near-flat top spot. The focal distance is 90mm from the upper surface of the cathode electrode plate, the spot size is 6mm, the laser power is 100W, the welding speed is 20mm / s, the welding trajectory is a straight line, and the laser welding environment is an air environment and no shielding gas is required.

[0068] S4 Welding Completed: After scanning is complete, wait for the current to drop to 0mA, turn off the electric field, and allow it to cool naturally to obtain the welded joint.

[0069] In this embodiment, the interface between the metal substrate (copper foil) and the glass substrate, achieved through a selective electrostatic precipitator (SEP) welding method using electric field composite glass and continuous laser, is smooth and continuous, with no obvious molten pool, indicating a solid-state bond between the two. The circuit current observed during the experiment demonstrates that sodium ions in the electrolyte glass migrate towards the cathode under the influence of the electric field and continuous laser. Testing showed that the room temperature shear strength of the welded joint between the metal substrate and the glass substrate in this embodiment reached 25.1 MPa.

[0070] Comparative Example 1: This invention discloses a method for selective laser welding of electric field composite glass and metal, which differs from Example 1 in that it includes the following steps:

[0071] S1 Surface Pretreatment: The surfaces of a 15μm thick metal substrate (aluminum foil) and a 1.05mm thick glass substrate (Corning 5318 glass substrate) were ultrasonically cleaned with alcohol and acetone and then dried.

[0072] S2 Sample Assembly: Clamp the metal substrate to be welded and the glass substrate together with a clamp.

[0073] S3 Continuous Laser Welding: The laser focus is positioned above the cathode electrode plate, and the focus is defocused relative to the interface between the metal substrate and the glass substrate. Based on a predetermined bow-shaped scanning path, the laser welding on the focal plane is completed, and the laser energy distribution is controlled to be a near-flat-top spot. The focal distance is 90mm from the upper surface of the cathode electrode plate, the spot size is 6mm, the laser power is 90W, the welding speed is 5mm / s, the welding trajectory is a straight line, the laser welding environment is an air environment, and no shielding gas is required. The current and voltage recorder is turned on.

[0074] S4 Welding Completed: After scanning is completed, the welded joint is obtained by natural cooling.

[0075] The metal substrate and glass substrate welded in this comparative example showed no connection after welding, and no welding marks were found on the surfaces of either substrate. No current was generated in the circuit, and the joint exhibited no shear strength. This indicates that the laser process in Comparative Example 1 cannot achieve an effective connection between the metal and glass substrates without an electric field.

[0076] Comparative Example 2: This is a method for selective laser welding of electric field composite glass and metal disclosed in this invention. The difference from Example 1 is that it includes the following steps:

[0077] S1 Surface Pretreatment: The surfaces of 1mm thick metal substrate (aluminum plate) and 1.05mm thick glass substrate (Corning 5318 glass substrate) are ultrasonically cleaned with alcohol and acetone and then dried.

[0078] S2 Sample Assembly: Clamp the metal substrate to be welded and the glass substrate together with a clamp.

[0079] S3 Continuous Laser Welding: The laser focus is positioned above the cathode electrode plate, and the focus is defocused relative to the interface between the metal substrate and the glass substrate. Based on a predetermined bow-shaped scanning path, the laser welding on the focal plane is completed, and the laser energy distribution is controlled to be a near-flat-top spot. The focal distance is 90mm from the upper surface of the cathode electrode plate, the spot size is 6mm, the laser power is 200W, the welding speed is 5mm / s, the welding trajectory is a straight line, the laser welding environment is an air environment, and no shielding gas is required. The current and voltage recorder is turned on.

[0080] S4 Welding Completed: After scanning is completed, the welded joint is obtained by natural cooling.

[0081] In this comparative example, the glass substrate cracked during the welding process of the metal-glass substrate weld joint, resulting in joint failure. An electron microscope image of the interface between the metal-glass substrate weld joint is shown below. Figure 10 As shown.

[0082] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for continuous laser selective welding of electric field composite glass and metal, characterized in that: Includes the following steps, S1 sequentially clamps a ceramic insulating sheet, an anode electrode plate, a metal substrate, a glass substrate, and a cathode electrode plate from bottom to top, and electrically connects the anode electrode plate and the cathode electrode plate to the power supply respectively. Then, the electric field device and the current and voltage recorder are turned on to complete the sample assembly. S2 places the laser focus above the cathode electrode plate, and the focus is defocused relative to the interface between the metal substrate and the glass substrate. Based on a predetermined scanning path, the laser welding on the focal plane is completed. After the S3 scan is completed, wait for the current to drop to 0mA, turn off the electric field, and allow it to cool naturally to obtain the welded joint.

2. The method for selective laser welding of electric field composite glass and metal according to claim 1, characterized in that: In step S1, the ceramic insulating sheet, anode electrode plate, metal substrate, glass substrate and cathode electrode plate are ultrasonically cleaned with alcohol and acetone respectively, and then dried.

3. The method for selective laser welding of electric field composite glass and metal according to claim 1, characterized in that: In step S1, the anode electrode plate and the cathode electrode plate are on the same plane as the outer surfaces of the metal substrate and the glass substrate, respectively, or are spaced apart.

4. The method for selective laser welding of electric field composite glass and metal according to claim 1, characterized in that: In S1, the anode electrode plate is made of one of the following materials: titanium alloy plate, stainless steel plate, and copper plate.

5. The method for selective laser welding of electric field composite glass and metal according to claim 1, characterized in that: In S1, the metal substrate is made of one of the following materials: pure aluminum foil, pure copper foil, stainless steel foil, and Kovar alloy plate.

6. The method for selective laser welding of electric field composite glass and metal according to claim 1, characterized in that: In S1, the glass substrate is made of electrolyte glass.

7. The method for selective laser welding of electric field composite glass and metal according to claim 1, characterized in that: In step S1, the cathode electrode plate is made of either ITO conductive glass substrate or FTO conductive glass substrate.

8. The method for selective laser welding of electric field composite glass and metal according to claim 1, characterized in that: In S1, the electric field of the control power supply is a constant voltage steady-state electric field with a voltage of 300~600V and a dielectric strength of 240~480V / mm. The direction of the electric field is from the anode electrode plate to the cathode electrode plate, and remains the same in the regions of the anode electrode plate and the cathode electrode plate, and is perpendicular to the metal substrate and the glass substrate. The electric field type is one of direct current, alternating current and pulse current.

9. The method for selective laser welding of electric field composite glass and metal according to claim 1, characterized in that: In S2, the scanning path is one or a combination of several of the following: line-by-line scanning path, bow-shaped scanning path, grid interlacing scanning path, concentric circle scanning path, and spiral line scanning path.

10. The method for selective laser welding of electric field composite glass and metal according to claim 1, characterized in that: In S2, the laser energy distribution is controlled to be a near-flat-top spot, the focal distance is 90~100mm from the upper surface of the cathode electrode plate, the spot size is 4~8mm, the laser power is 80~800W, and the welding speed is 1~20mm / s.

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