Three-dimensional package glass bonding apparatus and method thereof

Abstract

This invention relates to the field of semiconductor packaging equipment and process technology, specifically a three-dimensional packaging glass bonding device; it includes upper and lower vacuum chambers, upper and lower heating plates, a lifting cylinder, a pressing assembly with a counterweight plate, a pressurizing assembly with a servo cylinder, and a counterweight assembly; the device drives the chambers to close via the lifting cylinder, and the servo cylinder push rod, combined with a pressure sensor, separately abuts against the counterweight plate; its core is to use the counterweight assembly to suspend and offset most of the weight of the pressing assembly, while the servo cylinder only supplements the pressure difference to the target value, and provides mechanical clearance space through active retraction of the cylinder and suspension during thermal expansion; this invention effectively reduces the mechanical impact at the moment of contact with brittle glass, always maintaining the actual interface force equal to the target pressure, and avoiding additional compressive stress damage caused by thermal expansion.

Description

Technical Field

[0001] This invention relates to the field of semiconductor packaging equipment and process technology, specifically to a three-dimensional packaging glass bonding apparatus and method. Background Technology

[0002] In the current production environment of 3D packaging for semiconductor devices, brittle glass substrates need to undergo complex vacuum environment construction, variable temperature heating, and multi-stage pressurization processes during thermopressing bonding. To achieve tight bonding of glass substrates, existing solutions generally adopt a rigid direct-pressure architecture, which directly drives the heating head to generate displacement and apply a set load through a servo electric cylinder or hydraulic mechanism. Then, in a sealed cavity, a fixed program is executed to perform heating, pressure holding, and natural cooling. Although this solution has a certain pressing capability in the thermopressing scenario of conventional ductile materials, due to the high rigidity of its pressurization transmission chain and the lack of a physical yielding mechanism, the mechanical impact generated when the pressure head contacts the brittle glass is large. During the heating stage, the thermal expansion deformation of the glass can easily be converted into destructive additional compressive stress. During the cooling stage, the unloading action cannot dynamically match the nonlinear shrinkage rate of the material, making it difficult to support the fine packaging requirements of high dynamic response force control compensation and low microcrack rate.

[0003] Therefore, how to achieve flexible adaptive compensation of bonded loads and reduce mechanical stress damage throughout the thermodynamic cycle has become an urgent technical problem to be solved. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a three-dimensional encapsulation glass bonding apparatus and method. Specifically, the technical solution of this invention is as follows: A three-dimensional encapsulation glass bonding device, comprising: frame; The lower vacuum chamber is bolted to the middle platform of the frame. The lower heating plate is located inside the lower vacuum chamber; the upper vacuum chamber is located above the lower vacuum chamber and is slidably connected to the frame column via a guide optical axis. The lifting cylinder has its cylinder body fixed to the top crossbeam of the frame via a flange, and its piston rod fixed to the top surface of the upper vacuum chamber, so as to drive the chamber to rise and fall and engage with the lower vacuum chamber to form a sealed space. The pressing assembly includes a pressing spindle that passes vertically through the top surface of the upper vacuum chamber, and an upper heating plate and a counterweight plate that are respectively fixed to the bottom and top ends of the spindle and located inside and outside the upper vacuum chamber. The pressurization assembly includes a servo electric cylinder fixed to the top crossbeam of the frame, and a pressure sensor fixed to the bottom end of the push rod of the electric cylinder, with the lower end face used to separately abut against the top surface of the counterweight plate. The counterweight assembly includes a fixed pulley rotatably connected to the top of the frame via a pin shaft, a flexible steel wire rope that passes around the pulley and has its fixed end connected to the edge of the counterweight plate, and a counterweight block suspended from the suspension end of the steel wire rope. The controller is electrically connected to the lower heating plate, the upper heating plate, the lifting cylinder, the servo electric cylinder, and the pressure sensor.

[0005] In one possible implementation, cooling air knives are provided on the inner wall of the lower vacuum chamber, the cooling air knives are symmetrically distributed, and the air outlets of the cooling air knives are angled downwards and aligned with the central area of ​​the lower heating plate.

[0006] In one possible implementation, the lower heating plate is fixedly connected to the inner wall of the bottom surface of the lower vacuum cavity via a ceramic heat insulation pad; resistance heating wires are evenly distributed inside the lower heating plate.

[0007] In one possible implementation, the bottom opening size of the upper vacuum chamber matches the top opening size of the lower vacuum chamber; a fluororubber sealing ring is embedded at the joint surface of the sealed space formed by the upper vacuum chamber and the lower vacuum chamber.

[0008] In one possible implementation, the top surface of the upper vacuum cavity is provided with a through hole; the pressing spindle passes through the through hole; and a high-temperature resistant dynamic sealing ring is embedded in the inner wall of the through hole.

[0009] In one possible implementation, the counterweight is formed by stacking and connecting cast iron blocks of equal mass.

[0010] Three-dimensional encapsulation glass bonding methods include: S1. Obtain the target bonding pressure of the glass substrate to be bonded; obtain the total weight of the pressing spindle, the upper heating plate and the counterweight plate; adjust the weight of the counterweight so that the net physical weight after subtracting the tension of the counterweight from the total weight is less than the target bonding pressure. S2. Control the lifting cylinder to push the upper vacuum chamber down; control the upper vacuum chamber to fit with the lower vacuum chamber to form a sealed space and evacuate the vacuum. S3. Control the servo electric cylinder to push the pressure sensor downward to abut the counterweight plate, and continuously acquire the force value of the pressure sensor while controlling the servo electric cylinder to continue pushing the pressing spindle downward; S4. Obtain the force value of the pressure sensor; calculate the slope of the force value changing with time; when the slope is greater than the preset contact slope threshold, determine that the upper heating plate is in contact with the glass substrate, record the current push rod position as the physical contact zero point and stop descending; when the slope is less than or equal to the preset contact slope threshold, control the servo electric cylinder to continue pushing the pressing spindle downward. S5. Control the heating of the lower heating plate and the upper heating plate to rise; control the servo electric cylinder to extend the push rod to increase the force value to the target pressure difference value; wherein, the target pressure difference value is the difference between the target bonding pressure and the net physical gravity.

[0011] In one possible implementation, step S5 is followed by: S601. During the heating process, the pressure sensor monitors the total force state and obtains the force value. S602. When the applied force is greater than the target bonding pressure, the push rod of the servo cylinder is controlled to retract actively; when the applied force is less than or equal to the target bonding pressure, the position of the push rod of the servo cylinder remains unchanged. S603. The flexible steel wire rope provides suspension and buffer, causing the pressing spindle to move upward, thus maintaining the actual force on the pressing interface equal to the target bonding pressure.

[0012] In one possible implementation, a cooling air knife is provided on the inner wall of the lower vacuum chamber; wherein, a thermocouple is built into the lower heating plate; wherein, step S603 is followed by: S701. Obtain the bonding heat preservation and pressure holding time; when the bonding heat preservation and pressure holding time ends, turn on the cooling air knife to blow cooling gas into the sealed space; when the bonding heat preservation and pressure holding time has not ended, maintain the current state; S702. Obtain the temperature drop rate fed back by the thermocouple; obtain the initial thickness and coefficient of linear expansion of the glass substrate to be bonded; calculate the thickness shrinkage rate of the glass substrate based on the temperature drop rate, the initial thickness and the coefficient of linear expansion. S703. Control the retraction of the push rod of the servo electric cylinder according to the thickness shrinkage rate; control the reduction of the downward pressure compensation force until the push rod separates from the counterweight plate.

[0013] In one possible implementation, step S703 is followed by: S801. Continuously monitor the temperature and obtain the current temperature value; when the current temperature value is less than or equal to the safe discharge threshold, execute S802; when the current temperature value is greater than the safe discharge threshold, continue to obtain the current temperature value. S802. Control the lifting cylinder to lift the upper vacuum chamber to complete the bonding cycle.

[0014] The present invention has the following beneficial effects: 1. This invention utilizes a counterweight assembly in conjunction with a servo cylinder equipped with a pressure sensor. The lower end face of the pressure sensor at the bottom of the servo cylinder push rod is separately abutted against the counterweight plate. During pressurization, the counterweight block offsets most of the weight of the pressing assembly, and the servo cylinder only supplements the pressure difference to the target value, effectively reducing the mechanical impact at the moment of contact with brittle glass. During the heating process, the active retraction of the servo cylinder based on the force value and the suspension and buffering of the flexible steel wire rope allow the pressing spindle to move upward, providing mechanical clearance space for the thermal expansion of the glass, and always keeping the actual interface force equal to the target bonding pressure, thus avoiding additional compressive stress damage. 2. This invention incorporates a cooling air knife on the inner wall of the lower vacuum chamber and integrates a built-in thermocouple to achieve dynamic cooling and unloading control. After the heat preservation and pressure holding are completed, the cooling air knife blows cooling gas into the sealed space to accelerate cooling. The controller calculates the thickness shrinkage rate of the glass substrate based on the temperature drop rate fed back by the thermocouple, the initial thickness of the glass substrate to be bonded, and the coefficient of linear expansion. This allows for precise control of the servo electric cylinder push rod to retract synchronously, reducing the downward pressure compensation force until the push rod separates from the counterweight plate. This method enables the unloading action during the cooling stage to dynamically match the nonlinear shrinkage process of the material, effectively reducing the tensile and compressive coupling stress during the cooling stage and minimizing mechanical stress damage throughout the entire thermodynamic cycle. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings: Figure 1 This is a schematic diagram of the overall external structure of the device; Figure 2 This is a schematic diagram of the overall cross-sectional structure of the device; Figure 3 This is a schematic diagram of the lower vacuum chamber; Figure 4 This is a schematic diagram of the upper vacuum chamber; Figure 5 This is a flowchart of the method of the present invention.

[0016] In the diagram: 1. Frame; 2. Lower vacuum chamber; 3. Middle platform; 4. Lower heating plate; 5. Upper vacuum chamber; 6. Guide shaft; 7. Column; 8. Lifting cylinder; 9. Flange; 10. Top beam; 11. Piston rod; 12. Pressing assembly; 13. Pressing spindle; 14. Upper heating plate; 15. Counterweight plate; 16. Pressurizing assembly; 17. Servo electric cylinder; 18. Pressure sensor; 19. Push rod; 20. Counterweight assembly; 21. Flexible steel wire rope; 22. Fixed pulley; 23. Counterweight block; 24. Pin; 25. Cooling air knife; 26. Air outlet; 27. Ceramic heat insulation pad; 28. Resistance heating wire; 29. ​​Fluororubber sealing ring; 30. Through hole; 31. High-temperature resistant dynamic sealing ring; 32. Cast iron block; 33. Thermocouple. Detailed Implementation

[0017] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0018] Example 1: Combination Figure 1 and Figure 2 A three-dimensional encapsulation glass bonding device, comprising: Rack 1; The lower vacuum chamber 2 is bolted to the middle platform 3 of the frame 1; The lower heating plate 4 is located inside the lower vacuum chamber 2; the upper vacuum chamber 5 is located above the lower vacuum chamber 2 and is slidably connected to the column 7 of the frame 1 via the guide optical axis 6. The lifting cylinder 8 has its cylinder body fixed to the top crossbeam 10 of the frame 1 via flange 9, and its piston rod 11 fixed to the top surface of the upper vacuum chamber 5, so as to drive the chamber to rise and fall and engage with the lower vacuum chamber 2 to form a sealed space. The pressing assembly 12 includes a pressing spindle 13 that passes vertically through the top surface of the upper vacuum chamber 5, and an upper heating plate 14 and a counterweight plate 15 that are respectively fixed to the bottom and top ends of the spindle and located inside and outside the upper vacuum chamber 5. The pressurization assembly 16 includes a servo electric cylinder 17 fixed to the top crossbeam 10 of the frame 1, and a pressure sensor 18 fixed to the bottom end of the push rod 19 of the electric cylinder and whose lower end face is used to separate and abut against the top surface of the counterweight plate 15. The counterweight assembly 20 includes a fixed pulley 22 rotatably connected to the top of the frame 1 by a pivot 24, a flexible steel wire rope 21 that passes around the pulley and is fixedly connected to the edge of the counterweight plate 15, and a counterweight block 23 suspended at the suspension end of the steel wire rope. The controller is electrically connected to the lower heating plate 4, the upper heating plate 14, the lifting cylinder 8, the servo electric cylinder 17, and the pressure sensor 18, respectively. The frame 1 adopts a welded steel frame or a bolted thick plate frame, preferably a combination of rectangular tube and steel plate structure, to ensure that the upper actuator and lower vacuum chamber still have sufficient rigidity under high temperature conditions; combined with Figure 3 The lower vacuum chamber 2 is fixed to the central platform 3 of the frame 1, serving as the lower process space to support the glass substrate to be bonded; combined with Figure 4 The upper vacuum chamber 5 is positioned above the lower vacuum chamber 2 and reciprocates linearly along the vertical direction via the guide optical axis 6. Here, the guide shaft 6 refers to a surface-hardened and precision-ground linear guide shaft, which restricts the upper vacuum cavity 5 to move up and down only in the vertical direction, reducing the sway during the fastening process; preferably, linear bearings or guide sleeves are fixedly installed on both sides of the outer wall of the upper vacuum cavity 5, and the guide shaft 6 passes through the inside of the linear bearings or guide sleeves to achieve a low-friction sliding fit between the two. When the lifting cylinder 8 drives the upper vacuum chamber 5 to descend, the upper and lower vacuum chambers 2 form a sealed space to meet the atmospheric environment requirements for vacuuming and thermo-press bonding. The side wall of the lower vacuum chamber 2 or the upper vacuum chamber 5 is provided with a gas extraction port, which is sealed and connected to an external vacuum pump through a vacuum pipeline to extract gas from the sealed space. The pressing spindle 13 in the pressing assembly 12 passes vertically through the top surface of the upper vacuum chamber 5. The upper heating plate 14 is fixed to the lower end of the pressing spindle 13 and located inside the vacuum chamber, and is used to directly apply heat and pressure to the upper surface of the glass substrate. The counterweight plate 15 is fixed to the upper end of the pressing spindle 13 and located outside the vacuum chamber, and is used to receive external pressure and connect the counterweight assembly 20. The servo electric cylinder 17 in the pressurizing assembly 16 is used to provide adjustable compensation pressure. The pressure sensor 18 is installed at the bottom of the push rod 19 of the servo electric cylinder 17. Its lower end face is not fixedly connected to the top surface of the counterweight plate 15, but is in contact when working and separated when not working. This separation-type contact engagement allows the pressing spindle 13 to be subjected only to its own weight and the counterweight tension when not pressurized, which can avoid the impact formed by the traditional rigid connection mechanism when contacting the glass. The flexible steel wire rope 21 in the counterweight assembly 20 changes the direction of force through the fixed pulley 22, and the counterweight block 23 provides a constant upward pulling force to the counterweight plate 15; the flexible steel wire rope 21 here refers to a metal rope that allows for slight elastic deformation and bending. Its special meaning in this device is not only to transmit the pulling force, but also to provide a small displacement space for the pressing spindle 13 to be retracted. The controller can be implemented by combining an industrial computer, a programmable logic controller and a temperature control module, and is connected to the upper and lower heating plates 4, the lifting cylinder 8, the servo electric cylinder 17 and the pressure sensor 18 respectively, and is used to perform lifting, heating, pressure building and pressure compensation control. The device forms the basic pressure through the weight of the pressing spindle 13 and the upper heating plate 14, and offsets most of the basic pressure upward by the counterweight 23. The difference is then made up by the servo electric cylinder 17, so that the bonding pressure is formed by both mechanical coarse adjustment and electric fine adjustment. Compared to structures that rely solely on rigid electric cylinders for direct pressing, this structure exhibits a smoother force change at the moment of glass contact, reduces reliance on high-bandwidth servo force control under vacuum and high-temperature conditions, and is suitable for three-dimensional encapsulation thermocompression bonding of brittle glass products.

[0019] Cooling air knives 25 are provided on the inner wall of the lower vacuum chamber 2. The cooling air knives 25 are symmetrically distributed, and the air blowing ports 26 of the cooling air knives 25 are obliquely downward and aligned with the central area of ​​the lower heating plate 4. Cooling air knives 25 are provided on the inner wall of the lower vacuum chamber 2. Preferably, they are configured as two sets of symmetrical structures on the left and right. Each set of cooling air knives 25 is fixed to the side wall of the lower vacuum chamber 2 by bolts. The air blowing port 26 is inclined at a downward angle of 10° to 45° relative to the central area of ​​the lower heating plate 4, preferably 20° to 30°. The air inlet of the cooling air knife 25 is connected to an air inlet pipe connector that penetrates the side wall of the lower vacuum chamber 2, and a vacuum-resistant seal is provided at the penetration point. The air inlet pipe connector is used for controlled communication with an external cooling gas source. Here, the cooling air knife 25 refers to a directional air supply component with a slit-type or multi-hole air outlet. Its role in this invention is not only to introduce the cooling medium, but also to control the coverage and scouring direction of the cooling stream. The purpose of symmetrical distribution is to obtain a more uniform cooling airflow in the central area of ​​the lower heating plate 4 and the glass substrate above it, and reduce the local temperature difference caused by unilateral purging; the cooling medium can be air, nitrogen or inert gas, which is introduced into a closed space under vacuum release or controlled low pressure conditions. After the air outlet 26 is angled downwards and aligned with the center area of ​​the lower heating plate 4, the cooling airflow flows along the process area between the upper heating plate 14 and the lower heating plate 4, which is beneficial to accelerate the heat removal speed during the cooling stage after the bonding and holding pressure is completed, and works in conjunction with the retraction and unloading process of the servo electric cylinder 17 to gradually reduce the clamping force on the glass substrate during the cooling and shrinking process. Through trial production and verification, under the same heating power and the same glass size, the cooling stage using symmetrical air knife directional blowing improves the cooling rate of the process area compared to natural cooling, and the temperature distribution in the cooling area is more stable, which helps to reduce the risk of microcracks caused by inconsistent local thermal shrinkage.

[0020] The lower heating plate 4 is fixedly connected to the inner wall of the bottom surface of the lower vacuum cavity 2 by a ceramic heat insulation pad 27; resistance heating wires 28 are evenly distributed inside the lower heating plate 4; The lower heating plate 4 is fixed to the inner wall of the bottom surface of the lower vacuum chamber 2 by a ceramic heat insulation pad 27. The ceramic heat insulation pad 27 can be made of alumina ceramic plate, aluminum nitride ceramic plate or cordierite heat insulation component, and the thickness can be set from 3mm to 20mm to reduce the heat conduction of the lower heating plate 4 to the metal wall of the lower vacuum chamber 2 and keep the temperature rise of the chamber structure within a controllable range. The ceramic heat insulation pad 27 here refers to the heat insulation component that has both mechanical support and thermal barrier functions. It is not easy to release volatiles in high temperature and vacuum environments. The lower heating plate 4 is evenly distributed with resistance heating wires 28, preferably nickel-chromium alloy heating wires or embedded electric heating film, distributed in a ring, serpentine or matrix form to reduce the temperature gradient on the plate surface. The lower heating plate 4 can be made of high thermal conductivity aluminum alloy, copper alloy or stainless steel composite structure with anti-oxidation treatment on the surface. The flatness of the plate surface is preferably controlled within the range of 0.02mm to 0.10mm to ensure that the glass substrate is heated and stressed evenly. Because a ceramic heat insulation pad 27 is installed between the lower heating plate 4 and the lower vacuum chamber 2, more heat is retained in the process area, improving the energy utilization rate during the heating stage. At the same time, the temperature of the chamber wall decreases, which is beneficial to protecting the seals and sensors. The resistance heating wires 28 are evenly distributed and work in conjunction with the upper flexible pressing structure to maintain a relatively uniform temperature field on the glass substrate before and after being pressed, thereby reducing the additional mechanical stress caused by local expansion.

[0021] The bottom opening size of the upper vacuum chamber 5 matches the top opening size of the lower vacuum chamber 2; a fluororubber sealing ring 29 is embedded at the joint surface of the sealed space formed by the upper vacuum chamber 5 and the lower vacuum chamber 2. The bottom opening size of the upper vacuum chamber 5 and the top opening size of the lower vacuum chamber 2 are designed to match. Matching means that the two can form a predetermined sealed space after being fastened together. The relative misalignment of the opening edges is preferably no more than 1mm in order to form a stable seal. An annular sealing groove is provided at the joint surface of the upper and lower vacuum chambers 2, and a fluororubber sealing ring 29 is embedded in the sealing groove. The cross-section of the sealing ring can be circular, rectangular or lip-shaped, and preferably made of fluororubber material with a temperature resistance of 150℃ to 250℃. Here, the fluororubber sealing ring 29 refers to a circumferential sealing element that still maintains elastic compression and rebound capability under negative pressure and temperature rise conditions. After the lifting cylinder 8 drives the upper vacuum chamber 5 to press down into place, the fluororubber sealing ring 29 forms a compression seal between the upper and lower chamber mating surfaces to meet the subsequent vacuuming process. Since the opening sizes of the upper vacuum chamber 5 and the lower vacuum chamber 2 are matched, no additional lateral correction mechanism is needed when they are fastened. Stable alignment can be achieved with the help of the guide optical axis 6. This structure can reserve space for the upper opening of the robot arm. After the upper vacuum chamber 5 is lifted, the robot arm can complete the feeding and picking of materials from above without interference from the lateral pressure mechanism. For products whose glass substrate size specifications exceed the matching tolerance range of a single chamber, adaptation can be achieved by replacing the flange 9 adapter plate of the upper vacuum chamber 5 and the lower vacuum chamber 2 or by replacing the sealing ring groove.

[0022] The top surface of the upper vacuum chamber 5 has a through hole 30; the pressing spindle 13 passes through the through hole 30; and the inner wall of the through hole 30 is embedded with a high-temperature resistant dynamic sealing ring 31. A through hole 30 is provided on the top surface of the upper vacuum chamber 5 for the pressing spindle 13 to pass through. A sliding fit clearance is left between the through hole 30 and the pressing spindle 13. The clearance value can be controlled within the range of 0.05mm to 0.30mm to balance the smooth reciprocating motion of the spindle and the space for sealing. A high-temperature resistant dynamic sealing ring 31 is embedded in the inner wall of the through hole 30. The dynamic sealing ring can be a graphite-filled polytetrafluoroethylene sealing ring, a fluororubber lip sealing ring, or a metal spring-reinforced high-temperature resistant sealing ring. Here, the high-temperature dynamic seal ring 31 refers to a sealing element that allows relatively moving parts to pass through and maintains airtightness under high-temperature conditions. Unlike static seals, it needs to meet the requirements of friction, wear and vacuum retention at the same time. When the pressing spindle 13 moves up and down along the through hole 30, the dynamic seal ring envelops the outer circle of the spindle and maintains circumferential contact to reduce vacuum leakage. Since the counterweight plate 15 is located outside the upper vacuum chamber 5, and the servo cylinder 17 and pressure sensor 18 are also arranged outside the high temperature vacuum zone, only the pressing spindle 13 passes through the top surface of the upper vacuum chamber 5 to enter the chamber. Therefore, the through hole 30 and the dynamic sealing structure are the key parts connecting the external drive and the internal pressing parts. With the adoption of a high-temperature resistant dynamic seal, the pressing spindle 13 can make minute displacements during the contact identification, pressurization compensation and cooling unloading stages without significantly damaging the vacuum environment of the cavity, making it suitable for multiple cyclic operations.

[0023] The counterweight 23 is made of cast iron blocks 32 of equal mass stacked and connected together; The counterweight 23 is formed by stacking and connecting multiple cast iron blocks 32 of equal mass. Each cast iron block 32 can be machined into a central through hole 30 structure. Guide rods, lifting rods or connecting bolts are used to connect and lock the blocks to ensure stable hoisting. The mass of a single cast iron block 32 can be set to standard specifications such as 0.1kg, 0.2kg, 0.5kg or 1kg according to the equipment range. Equal mass modules are preferred so that the total mass of the counterweight can be discretely adjusted by increasing or decreasing the number of blocks. The equality of quality here means that the mass deviation of each individual counterweight 23 does not exceed 2% of the nominal value within the manufacturing tolerance range, so as to ensure that the change in tensile force is predictable when calculated by the number of pieces. The reason for using stacked and connected counterweights 23 instead of a whole counterweight is that there are differences in the material, thickness, area and target bonding pressure of the glass substrate to be bonded. It is necessary to change the upward tensile force by increasing or decreasing the number of counterweights 23 so that the net downward physical gravity formed by the pressing spindle 13 and the upper heating plate 14 is less than the target bonding pressure and within the preset difference range. With this discrete counterweight setting, the operator can directly select the number of counterweight pieces according to the process card without changing the main drive mechanism; cast iron material has a high density and is easy to process, making it suitable as a counterweight material; when it is necessary to reduce the volume, it can also be replaced with steel blocks of equal mass, as long as the equal mass pieces are stacked and connected.

[0024] Example 2: Combination Figure 5 Three-dimensional encapsulation glass bonding method, including: S1. Obtain the target bonding pressure of the glass substrate to be bonded; obtain the total weight of the pressing spindle 13, the upper heating plate 14 and the counterweight plate 15; adjust the weight of the counterweight 23 so that the net physical weight after subtracting the tension of the counterweight 23 from the total weight is less than the target bonding pressure. S2. Control the lifting cylinder 8 to push the upper vacuum chamber 5 down; control the upper vacuum chamber 5 to fit with the lower vacuum chamber 2 to form a sealed space and evacuate the vacuum. S3. Control the servo cylinder 17 to push the pressure sensor 18 downward to abut against the counterweight plate 15, and continuously acquire the force value of the pressure sensor 18 while the servo cylinder 17 continues to push the pressing spindle 13 downward. S4. Obtain the force value of the pressure sensor 18; calculate the slope of the force value changing over time; when the slope is greater than the preset contact slope threshold, determine that the upper heating plate 14 is in contact with the glass substrate, record the current position of the push rod 19 as the physical contact zero point and stop descending; when the slope is less than or equal to the preset contact slope threshold, control the servo electric cylinder 17 to continue pushing the pressing spindle 13 to descend. S5. Control the lower heating plate 4 and the upper heating plate 14 to heat up; control the servo electric cylinder 17 to extend the push rod 19 to increase the force value to the target pressure difference value; wherein, the target pressure difference value is the difference between the target bonding pressure and the net physical gravity. This method is used in the thermo-press bonding process of the aforementioned device, and the controller is preferably an industrial computer or a programmable logic controller. In S1, the target bonding pressure can be predetermined based on the glass substrate material, thickness, effective pressure area, and process documents. For example, for a 100mm x 100mm glass substrate, the target bonding pressure can be set to a value within the range of 50N to 500N. The total weight of the pressing spindle 13, the upper heating plate 14, and the counterweight plate 15 can be obtained by weighing or by converting the design mass of the components. The controller prompts the operator to increase or decrease the number of counterweights 23 based on the difference between the target bonding pressure and the total weight, so that the net physical weight is less than the target bonding pressure, preferably controlled within 60% to 95% of the target bonding pressure, so that the margin is made up by the servo electric cylinder 17. In S2, the robotic arm places the glass substrate on the lower heating plate 4, and the lifting cylinder 8 drives the upper vacuum chamber 5 to move down and fit into the lower vacuum chamber 2. After that, the vacuum pump is started to draw a vacuum. The vacuum level in the chamber can be set according to the process requirements, for example, from 10Pa to 5000Pa. During the vacuuming process, since the pressure sensor 18 has not yet pressed down on the counterweight plate 15, the pressing spindle 13 remains suspended in the upper position under the pull of the counterweight, and a gap is left between the upper heating plate 14 and the glass substrate to facilitate gas flow. In S3, the servo electric cylinder 17 descends at a low speed, preferably from 0.01 mm / s to 2 mm / s. After the lower end face of the pressure sensor 18 contacts the top surface of the counterweight plate 15, it continues to push, causing the pressing spindle 13 and the upper heating plate 14 to descend at a low speed. In S4, the controller continuously acquires the output value of the pressure sensor 18, and the sampling frequency can be from 50Hz to 1000Hz; the slope of the force value changing with time can be obtained by dividing the difference between adjacent sampling points by the sampling time interval, or by using the average slope of the sliding window. Specifically, when using the sliding window average slope, the controller internally constructs a first-in-first-out data queue of length N, where N is preferably between 5 and 20. In each sampling period, the latest force value collected by the pressure sensor 18 is enqueued, and the oldest force value is dequeued. The controller calculates the difference between the latest and oldest values ​​in the queue and divides this difference by N minus 1 times the sampling time interval to obtain the average slope of the current window. The specific calculation formula is as follows: in, The average slope of the current window. This represents the force value at the current sampling time. At the current sampling time, The oldest force value in the queue. The sampling time interval; The length of the aforementioned first-in-first-out data queue; This data processing method effectively filters out interference noise caused by high-frequency mechanical vibration in a single sampling, making the slope data input to the contact recognition unit smoother and improving the accuracy of contact determination; the preset contact slope threshold can be determined based on no-load test and contact test, for example, set to 5N / s to 100N / s; When the bottom surface of the upper heating plate 14 contacts the glass substrate, the motion resistance increases and the force slope of the sensor increases. Based on this, the controller determines that the bonding is complete and records the position of the servo electric cylinder 17 push rod 19 at this time as the physical contact zero point. This zero point is not the geometric installation zero position, but the actual contact position of the workpiece, which is used to eliminate the thickness deviation and clamping deviation of different batches of glass. In S5, the upper and lower heating plates 4 are heated synchronously according to the set heating curve, and the heating rate can be set from 1℃ / s to 20℃ / s; the servo electric cylinder 17 extends at low speed, so that the force value of the pressure sensor 18 gradually reaches the target pressure difference value. Since the target pressure difference is equal to the target bonding pressure minus the net physical weight, the total pressure actually borne on the glass substrate is the sum of the mechanical base pressure and the electric compensation pressure. This method allows most of the static load to be borne by the counterweight balance structure, and the servo electric cylinder 17 is only responsible for contact recognition and differential pressure application, which can reduce the impact at the moment of contact and reduce the drive power requirements. During the contact search phases of S3 and S4, the raw output of the pressure sensor 18 is mainly used to reflect the instantaneous thrust change transmitted from the servo electric cylinder 17 to the pressing spindle 13 via the counterweight plate 15; after entering the differential pressurization phase of S5, the controller combines the raw output with the net physical gravity determined in S1 to form the interface target force for process control. The pressure sensor 18 directly measures the compensated force part, while the force value used by the controller to determine the bonding state is based on the direct measurement value and combined with the known net physical gravity to obtain the control quantity; the purpose is to enable the same sensor to be used for both contact identification and subsequent total load control, while maintaining the technical logic of the two control targets, target pressure difference and target bonding pressure, to be consistent. The above force interpretation logic can be understood inside the controller as consisting of two sequential processing units: the first unit is the contact recognition unit, whose input is the original force value and sampling time continuously collected by the pressure sensor 18, and whose output is the force slope and the determination result of whether physical contact has occurred. The second unit is the load conversion unit. Its inputs are the current force value output by the first unit, the net physical gravity set in S1, and the current process stage identifier. Its output is the interface force control value used for comparison control. During the contact recognition phase, the controller prioritizes using the slope result to determine whether the bond is in place; during the differential pressurization and heating phase, the controller prioritizes using the interface force control value after load conversion to determine whether the target bonding pressure has been reached. Through this phased data flow, the same set of sampling data plays different functions at different process stages, avoiding confusion between contact determination criteria and pressure holding control criteria. The slope of the force value in S4 as a function of time is used to characterize the rate at which the motion resistance of the pressing spindle 13 increases when the servo electric cylinder 17 continues to press down. Before the upper heating plate 14 contacts the glass substrate, the pressing spindle 13 mainly overcomes its own weight balance and dynamic seal friction, and the rate of change of the force value is lower than the preset contact threshold. After physical contact occurs, continued pressing will cause the contact reaction force to increase with the increase of displacement, so the slope changes from a low value to a value higher than the contact threshold. The preferred method for determining the preset contact slope threshold is to first perform no-load calibration and then perform test piece contact calibration: during no-load calibration, the upper limit of the natural fluctuation slope of the pressure sensor 18 in the state of no glass contact is recorded; during test piece contact calibration, the slope range at the moment of initial contact between the upper heating plate 14 and the standard thickness glass substrate is recorded; the controller sets the preset contact slope threshold after leaving a safety margin between the two. The purpose of this setting is to make the threshold both higher than the non-contact numerical fluctuations caused by mechanical friction, vibration and sampling noise, and lower than the typical slope during actual contact, so that the fit determination in S4 is repeatable. S4 and S5 can be implemented in the following order without using complex integration formulas: Step 1: The controller reads the current value of pressure sensor 18 at a fixed sampling period and records the corresponding time synchronously; Step 2: Compare the current force value with the force value at the previous sampling time to obtain the force increment for this cycle; Step 3: Divide the force increment by the sampling time interval to obtain the slope value of the current cycle, or average the slope values ​​of multiple consecutive cycles to suppress interference; Step 4: Compare the slope value with the preset contact slope threshold. If the threshold is not reached, maintain the low-speed downward pressure and repeat steps 1 to 4. If the threshold is reached, immediately stop the downward movement and record the current position of push rod 19 as the physical contact zero point. Step 5: Based on the physical contact zero point, the controller switches to the differential pressurization stage, reads the target bonding pressure and net physical gravity, and obtains the target pressure difference; Step six: The servo electric cylinder 17 continues to extend at a speed no higher than that of the contact search phase or lower. The controller reads the force value of the pressure sensor 18 in real time and compares it with the target pressure difference. If it is lower than the target pressure difference, it continues to extend slightly. If it reaches the target pressure difference, it maintains the current position. Therefore, the output of the S4 process is the physical contact zero point and the contact determination result, and the output of the S5 process is the established compensation force target value; the former is used as the subsequent displacement control benchmark, and the latter is used as the force control benchmark in the subsequent heating and pressure holding stage.

[0025] The steps following S5 include: S601. During the heating process, the total force state is monitored and the force value is obtained by the pressure sensor 18. S602. When the applied force is greater than the target bonding pressure, the push rod 19 of the servo cylinder 17 is controlled to retract actively; when the applied force is less than or equal to the target bonding pressure, the position of the push rod 19 of the servo cylinder 17 remains unchanged. S603. The pressing spindle 13 is displaced upward by the suspension and buffering of the flexible steel wire rope 21, so that the actual force on the pressing interface is equal to the target bonding pressure. After the target pressure difference is established in S5, the glass substrate and the upper and lower heating plates 4 continue to heat up. The glass material will increase in thickness slightly due to thermal expansion. If the pressurization mechanism adopts a rigid locking method, the increase in glass thickness will be directly converted into additional compressive stress. Therefore, S601 to S603 are set in this method. In S601, the controller continuously reads the force value of the pressure sensor 18 to reflect the total force state transmitted from the pressing interface to the counterweight plate 15. In S602, when the detected force value exceeds the target bonding pressure, it indicates that thermal expansion has increased the interface load. The controller sends a retraction command to the servo cylinder 17. The retraction amount can be calculated based on the overpressure value and the equivalent stiffness of the system, or it can be retracted in a step-by-step manner, for example, retracting 0.001mm to 0.05mm each time and then re-detecting. When the overpressure value is converted to the equivalent stiffness of the system, the equivalent stiffness of the system is obtained in advance through the offline calibration program. That is, in the state without the glass substrate, the servo cylinder 17 is controlled to press down so that the pressure sensor 18 abuts against the counterweight plate 15 and continues to slowly extend. The ratio of the force increment to the displacement increment of the push rod 19 is recorded and stored in the controller. In S602, the overpressure calculated by the comparison subunit is used as input data and flows to the release subunit. The release subunit divides the overpressure by the system's equivalent stiffness to calculate the theoretical retraction displacement, and generates a position control command for the servo electric cylinder 17 accordingly. Specifically, the theoretical retraction displacement... The calculation formula is: in, This represents the current force value. For target bonding pressure, The equivalent stiffness of the system calibrated offline; for example, when the target bonding pressure is The current force value is The system's equivalent stiffness is calibrated as follows: At that time, the calculated theoretical retraction displacement was This data conversion based on equivalent stiffness transforms mechanical overshoot into displacement execution. Comparative tests showed that the active retraction driven by this stiffness conversion model reduced the peak value of interface pressure fluctuation by about 30% compared with the fixed step retraction, effectively supporting the technical effect of maintaining the stability of the actual force on the bonding interface; when the force value is less than or equal to the target bonding pressure, the servo electric cylinder 17 maintains the current position to maintain the existing compensation force. In S603, since the counterweight plate 15 is connected to the counterweight block 23 by the flexible steel wire rope 21, and the servo cylinder 17 and the counterweight plate 15 are in separate contact, the servo cylinder 17 retracts and presses the spindle 13, which is not rigidly locked, but is allowed to move slightly upward under the combined action of glass expansion push and counterweight pulling force. The suspension buffer here refers to the flexible steel wire rope 21 allowing the system to undergo small displacement and slight elastic elongation when transmitting tension, thereby providing mechanical clearance space for thermal expansion release; the operability of this method is that the force value collected by the pressure sensor 18 directly participates in the retraction control of the servo electric cylinder 17, and the retraction action is converted into the upward movement of the main shaft through the retractable characteristics of the flexible steel wire rope 21. The two together keep the actual force of the pressing interface near the target bonding pressure; When testing brittle glass substrates with a thickness of 0.2 mm to 1.1 mm, the pressure fluctuation amplitude during the heating stage can be limited to the range allowed by the process, and the glass breakage rate is reduced compared to the rigid pressing method; The force value monitored and acquired in S601 is the result of the controller processing and converting the measured value of the pressure sensor 18. Specifically, based on the known net physical gravity in S5, the controller takes the current output of the pressure sensor 18 as the compensation force observation and superimposes it with the predetermined net physical gravity to obtain the force value corresponding to the total force state for comparison in S601 and S602. Therefore, the control quantity used in stage S5 to establish the target pressure difference and the control quantity used in stages S601 and S602 to compare the target bonding pressure belong to different levels of the same force transmission chain. The former focuses on the establishment of compensation force, while the latter focuses on the maintenance of the total interface load. Therefore, the two are logically progressive rather than contradictory. To make the above control relationship clearer, S601 to S603 can be understood as a temperature rise and pressure hold compensation control program; the purpose of this control program is to solve the problem of passive increase of interface load caused by thermal expansion of glass; the control program logically includes a monitoring subunit, a comparison subunit, and a release subunit: the monitoring subunit receives the continuous output of pressure sensor 18 and the current process stage information to form the current force control value; The comparison subunit compares the force control value with the target bonding pressure and outputs the overpressure judgment result and the overpressure level; the release subunit drives the servo electric cylinder 17 to hold or retract according to the comparison result, and uses the suspension characteristics of the flexible steel wire rope 21 to convert the retraction action into the upward movement of the pressing spindle 13. The model as a whole represents the following physical relationship: the thermal expansion of glass will reduce the mechanism's clearance and increase the interface reaction force, while when the external rigid pressure decreases, the flexible suspension structure allows the spindle to undergo micro-displacement following the change in workpiece thickness, thereby causing the interface load to fall back and stabilize near the target range. The logical meaning of the total force state in S601 in this method is: the combined force state currently borne by the pressure sensor 18, which is formed by the reaction force of the pressing interface, the force transmitted by the pressing spindle 13, and the compensation force of the servo electric cylinder 17. Its purpose is not to separate the sources of each force individually, but to serve as a unified monitoring parameter for judging whether the actual load on the interface deviates from the target bonding pressure. Since the physical contact zero point and target pressure difference have been established in stage S5, the force value continuously acquired in S601 can be directly used as the closed-loop monitoring input during the heating process. When the force value continues to increase due to the thermal expansion of the glass, it indicates that the actual force at the pressing interface has an upward trend, and the retraction control in S602 is triggered accordingly. The processing flow from S601 to S603 is preferably executed cyclically in the following order: The first step is for the controller to read the pressure sensor 18 value at a fixed sampling period and compare the value with the target bonding pressure; The second step is to output a hold command if the current force value is not greater than the target bonding pressure, so that the servo cylinder 17 push rod 19 stays in the current position and enters the next sampling cycle. The third step is to identify the excess force as overpressure if the current force value is greater than the target bonding pressure. The fourth step is for the controller to select the retraction method based on the overpressure amount. When the overpressure amount is less than or equal to the preset overpressure threshold, a single set step size retraction is used. When the overpressure amount is greater than the preset overpressure threshold, multiple step retractions are used. The force value is reread after each retraction. Fifth, the controller continues to monitor the force value after retraction until it falls back to near the target bonding pressure, at which point further retraction stops. The final output of this process is the position of the retracted push rod 19 and the updated force balance state, which directly serves to maintain the stabilizing force in the subsequent heat preservation and pressure holding stages. In S603, sampling, comparison, and micro-retraction are used to keep the actual force on the bonding interface within the allowable fluctuation range near the target bonding pressure. This allowable fluctuation range can be preset according to the glass material, area, and process tolerance. For example, it can be limited to ±2% to ±10% of the target bonding pressure, or the absolute value error can be limited to no more than 2N to 20N.

[0026] A cooling air knife 25 is provided on the inner wall of the lower vacuum chamber 2; wherein, a thermocouple 33 is built into the lower heating plate 4; wherein, after step S603, the following is included: S701. Obtain the bonding heat preservation and pressure holding time; when the bonding heat preservation and pressure holding time ends, turn on the cooling air knife 25 to blow cooling gas into the sealed space; when the bonding heat preservation and pressure holding time has not ended, maintain the current state; S702, Obtain the temperature drop rate fed back by thermocouple 33; Obtain the initial thickness and coefficient of linear expansion of the glass substrate to be bonded; Calculate the thickness shrinkage rate of the glass substrate based on the temperature drop rate, initial thickness and coefficient of linear expansion. S703. Control the push rod 19 of the servo electric cylinder 17 to retract according to the thickness shrinkage rate; control the reduction of the downward pressure compensation force until the pressure sensor 18 separates from the counterweight plate 15; The lower heating plate 4 has a built-in thermocouple 33. The thermocouple 33 is preferably embedded near the center of the lower heating plate 4. Multiple thermocouples 33 can also be set for average temperature calculation. The thermocouple 33 here refers to the temperature sensing element used to measure the temperature of the lower heating plate 4 and output the corresponding electrical signal to the controller. The temperature it measures can approximately represent the temperature change of the lower surface of the glass substrate. In S701, the controller determines whether to enter the cooling stage based on the preset bonding heat preservation and pressure holding time. The heat preservation and pressure holding time can be set from 10s to 1800s depending on the bonding material and thickness. After the time reaches the set value, the controller opens the air passage valve of the cooling air knife 25 to introduce cooling gas into the sealed space. If the time has not been reached, the current heating and pressurization state is maintained. In S702, the controller reads the temperature value of thermocouple 33 at a fixed sampling period and obtains the temperature drop rate by dividing the temperature difference between adjacent moments by the sampling time. The thickness shrinkage rate of a glass substrate can be calculated based on the coefficient of linear expansion of the glass material and the temperature change. If approximated by a linear change in the thickness direction, the thickness shrinkage rate per unit time can be obtained by multiplying the initial thickness of the glass substrate, the coefficient of linear expansion, and the temperature drop rate. For common glass materials, the coefficient of linear expansion can be input into the controller from a material database, for example... to The specific calculation formula is as follows: in, For thickness shrinkage rate, The initial thickness of the glass substrate is denoted as . is the coefficient of linear expansion of the glass material. The rate of temperature decrease; for example, for an initial thickness of The coefficient of linear expansion is The glass substrate, when the temperature decreases at a rate of At that time, the calculated thickness shrinkage rate was ; In S703, the controller calculates the retraction speed of the servo cylinder 17 based on the thickness shrinkage rate, so that the downward pressure compensation force decreases synchronously with the shrinkage of the glass. The calculation method can be to follow the displacement by an equal amount or to adopt a force value segmented retraction strategy until the push rod 19 of the servo cylinder 17 disengages from the counterweight plate 15. Specifically, when the displacement equal-volume following strategy is used to calculate the retraction speed, the execution instruction generation link inside the controller receives the thickness shrinkage rate output by the previous link, multiplies the thickness shrinkage rate by a preset compensation coefficient, preferably 1.0 to 1.2, to compensate for the slight hysteresis deformation of the flexible steel wire rope 21 and the seal, calculates the target retraction speed, and converts the target retraction speed into the drive pulse frequency of the servo electric cylinder 17 for output. In terms of theoretical basis, since the thickness shrinkage of glass during the cooling process is a dynamic process that slows down nonlinearly with temperature, the dynamic retraction speed calculated by the above real-time data flow can make the retraction trajectory of the servo electric cylinder 17 push rod 19 closely follow the actual shrinkage curve of the glass. Through trial production and verification, when unloading a 100mm x 100mm glass substrate with a thickness of 0.5mm during cooling, the sample that adopts dynamic speed adjustment unloading following the thickness shrinkage rate has a lower rate of edge microcracks than the sample that adopts constant speed unloading, which can effectively reduce the tensile and compressive coupling stress during the cooling period. After the pressure sensor 18 is separated from the counterweight plate 15, the upper heating plate 14 only lightly presses the glass substrate by net physical gravity to avoid surface micro-cracks caused by continuous large normal force and interface friction during cooling and contraction; the cooling air knife 25 accelerates the cooling and is unloaded synchronously by the servo electric cylinder 17, which can control the stress level during the cooling stage while accelerating the cooling process. In S702, the glass substrate thickness shrinkage rate is calculated based on the temperature drop rate, providing S703 with unloading rhythm parameters that match the cooling process. The estimation algorithm consists of three consecutive processing steps in the data stream: the first step is temperature change extraction, which receives continuous temperature values ​​from thermocouple 33 and outputs the current cooling rate; the second step is material property matching, which calls the linear expansion coefficient, target thickness, or preset process parameter range corresponding to the current glass model and outputs the thickness shrinkage trend under the current cooling conditions; the third step is instruction generation, which generates the retraction speed, retraction step size, or holding instruction of servo electric cylinder 17 based on the shrinkage trend. The logic as a whole represents the following physical relationship: During the cooling process, the thickness dimension of the glass will decrease due to thermal contraction. If the external compensation pressure does not decrease accordingly, the interface normal force and friction stress may deviate from the allowable range of the process. Therefore, it is necessary to convert the temperature change information into unloading control information. When using the above-mentioned cooling contraction estimation algorithm, the controller prefers not to directly use the temperature fluctuation of a single sampling point to drive the retraction, but to make a judgment based on the temperature change trend of multiple consecutive sampling cycles. The reason is that in the initial stage of the opening of the cooling air knife 25, there may be local airflow disturbance, short-term response lag of thermocouple 33, or redistribution of the temperature field inside the cavity. If a large retraction is executed directly based on the instantaneous change value, it may lead to unloading too quickly. To this end, the controller can first determine whether the temperature has entered a continuous decreasing state, and then determine the shrinkage level corresponding to the thickness shrinkage rate based on the temperature decrease rate in the continuous decreasing state, so that the unloading action is more consistent with the actual shrinkage process of the glass. In S702, the temperature drop rate is used to characterize how fast the temperature of the glass substrate changes during the current cooling process; the thickness shrinkage rate is used to characterize the magnitude of the tendency for the glass thickness to shorten under the temperature change condition. The controller does not directly measure the instantaneous change in glass thickness. Instead, it uses the temperature information fed back by thermocouple 33 and the pre-recorded linear expansion coefficient of the glass material to perform logical calculations, thereby converting the temperature field change into a displacement or velocity reference quantity that can be used for unloading control. The technical significance is that the faster the cooling, the more obvious the trend of glass thickness shrinkage. If the servo electric cylinder 17 still maintains the original downward compensation force, it is easier to form additional frictional stress and local tension-compression coupling stress at the interface. Therefore, it is necessary to simultaneously execute the retraction of push rod 19 in S703. S702 and S703 can be processed using the following steps: Step 1: After entering the cooling phase, the controller reads the temperature value of thermocouple 33 at a fixed cycle and saves the current temperature and the temperature of the previous cycle. Step two: The controller compares two adjacent temperature values ​​to obtain the temperature change for the current cycle; Step 3: Correspond the temperature change to the sampling time interval to obtain the temperature decrease rate; Step 4: The controller calls the linear expansion coefficient corresponding to the current glass substrate and converts the temperature drop rate into the thickness shrinkage rate. Step 5: The controller selects the retraction method based on the thickness shrinkage rate. When the thickness shrinkage rate is less than or equal to the preset shrinkage rate threshold, it adopts continuous first preset speed retraction. When the thickness shrinkage rate is greater than the preset shrinkage rate threshold, it adopts second preset speed retraction greater than the first preset speed or segmented step retraction. Step 6: After each retraction, reread the temperature of thermocouple 33 and the force value of pressure sensor 18 to determine whether unloading still needs to continue. Step 7: When the pressure sensor 18 separates from the counterweight plate 15, the controller recognizes this state as the active compensation force has been completely removed and stops pressing down further. The output of this process is a retraction speed or retraction step size that is adapted to the cooling process, and its flow is directly used to drive the servo electric cylinder 17 to perform the unloading action. In S703, separation of the pressure sensor 18 from the counterweight plate 15 can be determined by any of the following methods: First, the force value of the pressure sensor 18 drops to near the no-load contact value or below the preset separation threshold; Secondly, the controller detects that when the servo cylinder 17 continues to retract slightly, the force value of the pressure sensor 18 no longer changes with the displacement, and it can be determined that the contact has been lost. Third, the displacement is compared with the previously recorded contact zero point by combining the position of the servo electric cylinder 17. After the preset separation displacement is achieved, the force value is used for verification. The separation threshold is preferably obtained from the no-load test and is used to distinguish between the residual force still in contact and the zero drift noise after complete separation. By setting the above separation criteria, the unloading endpoint in S703 can have a clear basis for judgment, avoiding the impact of insufficient or excessive retraction on subsequent safe material discharge.

[0027] The steps following S703 include: S801: Continuously monitor the temperature and obtain the current temperature value; when the current temperature value is less than or equal to the safe discharge threshold, execute S802; when the current temperature value is greater than the safe discharge threshold, continue to obtain the current temperature value. S802, control the lifting cylinder 8 to lift the upper vacuum chamber 5 to complete the bonding cycle; After the compensation force is unloaded in S703, the controller continues to monitor the current temperature value using the built-in thermocouple 33 of the lower heating plate 4. The safe discharge threshold in S801 is determined based on the allowable handling temperature of the glass material, the temperature resistance of the material held by the robot arm, and the requirements of subsequent processes. It can be set from 40℃ to 120℃. The controller periodically reads the temperature of thermocouple 33. When the current temperature is still higher than the safe discharge threshold, it maintains the operation of cooling air knife 25 or reduces the air volume according to process requirements, and continues to monitor the temperature. When the current temperature is lower than or equal to the safe discharge threshold, it issues a cavity lifting command. In S802, the lifting cylinder 8 drives the upper vacuum chamber 5 to rise along the guide optical axis 6, causing the upper and lower vacuum chambers 2 to separate. The robot arm enters the upper opening area to take out the glass product that has been bonded and can then place the next glass substrate to be processed. This step, in conjunction with the aforementioned flexible pressurization, thermal expansion compensation and cooling unloading methods, forms a complete bonding cycle. Since the discharge operation is carried out after the temperature reaches the predetermined threshold, the risk of thermal shock and product warping caused by handling at high temperatures can be reduced, and the equipment can enter the next cycle as soon as the safety conditions are met.

[0028] 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 the above 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.

Claims

1. A three-dimensional encapsulation glass bonding device, characterized in that, include: Rack (1); The lower vacuum chamber (2) is bolted to the middle platform (3) of the frame (1); The lower heating plate (4) is located inside the lower vacuum chamber (2); the upper vacuum chamber (5) is located above the lower vacuum chamber (2) and is slidably connected to the column (7) of the frame (1) via the guide optical axis (6); The lifting cylinder (8) has its cylinder body fixed to the top beam (10) of the frame (1) via flange (9), and the piston rod (11) is fixed to the top surface of the upper vacuum chamber (5) to drive the chamber to rise and fall and engage with the lower vacuum chamber (2) to form a sealed space. The pressing assembly (12) includes a pressing spindle (13) that passes vertically through the top surface of the upper vacuum chamber (5), and an upper heating plate (14) and a counterweight plate (15) that are respectively fixed to the bottom and top ends of the spindle and located inside and outside the upper vacuum chamber (5). The pressurization assembly (16) includes a servo electric cylinder (17) fixed to the top crossbeam (10) of the frame (1) and a pressure sensor (18) fixed to the bottom end of the push rod (19) of the electric cylinder and whose lower end face is used to separate and abut against the top surface of the counterweight plate (15). The counterweight assembly (20) includes a fixed pulley (22) rotatably connected to the top of the frame (1) by a pivot (24), a flexible steel wire rope (21) that passes around the pulley and is fixedly connected to the edge of the counterweight plate (15), and a counterweight block (23) suspended at the suspension end of the steel wire rope. The controller is electrically connected to the lower heating plate (4), the upper heating plate (14), the lifting cylinder (8), the servo electric cylinder (17), and the pressure sensor (18), respectively.

2. The three-dimensional encapsulation glass bonding device according to claim 1, characterized in that, Cooling air knives (25) are provided on the inner wall of the lower vacuum cavity (2); the cooling air knives (25) are symmetrically distributed, and the air outlets (26) of the cooling air knives (25) are obliquely downward aligned with the central area of ​​the lower heating plate (4).

3. The three-dimensional encapsulation glass bonding device according to claim 2, characterized in that, The lower heating plate (4) is fixedly connected to the inner wall of the bottom surface of the lower vacuum cavity (2) by a ceramic heat insulation pad (27); the lower heating plate (4) is evenly distributed with resistance heating wires (28).

4. The three-dimensional encapsulation glass bonding device according to claim 3, characterized in that, The bottom opening size of the upper vacuum chamber (5) matches the top opening size of the lower vacuum chamber (2); a fluororubber sealing ring (29) is embedded at the joint surface of the sealed space formed by the upper vacuum chamber (5) and the lower vacuum chamber (2).

5. The three-dimensional encapsulation glass bonding device according to claim 4, characterized in that, The upper vacuum cavity (5) has a through hole (30) on its top surface; the pressing spindle (13) passes through the through hole (30); and the inner wall of the through hole (30) is fitted with a high-temperature resistant dynamic sealing ring (31).

6. The three-dimensional encapsulation glass bonding device according to claim 5, characterized in that, The counterweight (23) is formed by stacking and connecting cast iron blocks (32) of equal mass.

7. A three-dimensional encapsulation glass bonding method, applied to the three-dimensional encapsulation glass bonding apparatus of claim 1, characterized in that, include: S1. Obtain the target bonding pressure of the glass substrate to be bonded; Obtain the total weight of the pressing spindle (13), the upper heating plate (14) and the counterweight plate (15); adjust the weight of the counterweight (23) so that the net physical weight after subtracting the tension of the counterweight (23) from the total weight is less than the target bonding pressure; S2. Control the lifting cylinder (8) to push the upper vacuum chamber (5) down; control the upper vacuum chamber (5) to fit with the lower vacuum chamber (2) to form a sealed space and evacuate the vacuum. S3. Control the servo cylinder (17) to push the pressure sensor (18) downward to abut the counterweight plate (15), and continuously acquire the force value of the pressure sensor (18) while controlling the servo cylinder (17) to continue pushing the pressing spindle (13) downward. S4. Obtain the force value of the pressure sensor (18); calculate the slope of the force value changing with time; when the slope is greater than the preset contact slope threshold, determine that the upper heating plate (14) is in contact with the glass substrate, record the current position of the push rod (19) as the physical contact zero point and stop descending; when the slope is less than or equal to the preset contact slope threshold, control the servo electric cylinder (17) to continue pushing the pressing spindle (13) to descend; S5. Control the heating of the lower heating plate (4) and the upper heating plate (14) to rise; control the servo electric cylinder (17) to extend the push rod (19) to raise the force value to the target pressure difference value; wherein, the target pressure difference value is the difference between the target bonding pressure and the net physical gravity.

8. The three-dimensional encapsulation glass bonding method according to claim 7, characterized in that, The step S5 is followed by: S601. During the heating process, the total force state is monitored and the force value is obtained through the pressure sensor (18); S602. When the force value is greater than the target bonding pressure, the push rod (19) of the servo electric cylinder (17) is controlled to actively retract; when the force value is less than or equal to the target bonding pressure, the position of the push rod (19) of the servo electric cylinder (17) remains unchanged. S603. The pressing spindle (13) is displaced upward by the suspension buffer of the flexible steel wire rope (21), so that the actual force on the pressing interface is equal to the target bonding pressure.

9. The three-dimensional encapsulation glass bonding method according to claim 8, characterized in that, A cooling air knife (25) is provided on the inner wall of the lower vacuum cavity (2); wherein, a thermocouple (33) is built into the lower heating plate (4); wherein, after step S603, the following is included: S701. Obtain the bonding heat preservation and pressure holding time; when the bonding heat preservation and pressure holding time ends, turn on the cooling air knife (25) to blow cooling gas into the sealed space; when the bonding heat preservation and pressure holding time has not ended, maintain the current state; S702, Obtain the temperature drop rate fed back by the thermocouple (33); Obtain the initial thickness and coefficient of linear expansion of the glass substrate to be bonded; Calculate the thickness shrinkage rate of the glass substrate based on the temperature drop rate, the initial thickness and the coefficient of linear expansion; S703. Control the push rod (19) of the servo electric cylinder (17) to retract according to the thickness shrinkage rate; control the reduction of the downward pressure compensation force until the push rod (19) separates from the counterweight plate (15).

10. The three-dimensional encapsulation glass bonding method according to claim 9, characterized in that, The step S703 is followed by: S801. Continuously monitor the temperature and obtain the current temperature value; when the current temperature value is less than or equal to the safe discharge threshold, execute S802; when the current temperature value is greater than the safe discharge threshold, continue to obtain the current temperature value. S802, control the lifting cylinder (8) to lift the upper vacuum chamber (5) to complete the bonding cycle.

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