High-precision hot pressing process of capacitive screen

Abstract

The invention relates to the technical field of capacitive screens, in particular to a high-precision hot pressing process of a capacitive screen. Comprising the following steps: step 1, defining and calibrating a key monitoring area and a non-key monitoring area; step 2, embedding a micro temperature sensor array and a micro pressure sensor array, establishing a hot-pressing surface and a pressure-bearing surface, and ensuring that the sensor layout density in the key monitoring area is higher than that in the non-key area; 3, ensuring that the calibrated key monitoring area corresponds to the non-key monitoring area; 4, executing a hot pressing process, and setting a plurality of continuous process monitoring nodes in a linear pressing stage; synchronously acquiring and recording full-field data of the sensor array; on the basis of comparison between the full-field data and node full-field data in a preset data model, triple monitoring judgment is executed in sequence; and 5, the linear pressing stage is finished, and whether subsequent pressure maintaining and cooling operation is executed or not is judged based on the triple monitoring judgment result.

Description

Technical Field

[0001] This invention belongs to the field of capacitive screen technology, specifically relating to a high-precision hot-pressing process for capacitive screens. Background Technology

[0002] In the production of capacitive touchscreens, the hot-pressing process is a crucial step in connecting the glass panel to the flexible printed circuit board (FPC), and its quality directly determines the product's conductivity, sealing performance, and long-term stability. Traditional hot-pressing processes heavily rely on pre-set fixed time-temperature-pressure curves and operator experience. Because it's impossible to perceive the microscopic pressure and temperature distribution at the bonding interface in real time, especially in critical connection areas such as the bezel and integrated circuit (IC) pins, localized undervoltage, overheating, or uneven pressure can easily occur due to material deformation, equipment fluctuations, or environmental interference. These microscopic process defects are often hidden and only discovered during final performance testing, causing fluctuations in product yield, batch rework, and even reliability failures during use, becoming a long-standing technical challenge for the industry.

[0003] To improve process controllability and quality consistency, existing technologies have been improved. For example, patent application CN202410574919.5 discloses a capacitive touchscreen hot-pressing process and a capacitive touchscreen. This solution introduces temperature sensors, pressure sensors, and a controller to acquire pressing data during the pressing process and uses the performance test results after pressing to adjust process parameters, aiming to optimize subsequent production. This solution represents an advancement from "open-loop" experience-based operation to "data-assisted" closed-loop control, attempting to solve the problem of blind process adjustments through sensing and feedback mechanisms.

[0004] However, such existing technical solutions still have significant limitations. First, their sensing layout is usually a general or evenly distributed pattern, failing to prioritize monitoring resources for critical areas that determine product failure (such as sealing frames and fine pins). This makes it difficult to achieve high-resolution, high-precision status perception of the most critical parts while keeping costs under control, and thus unable to accurately capture local anomalies. Second, their data utilization and judgment logic are relatively crude, often focusing on monitoring overall average parameters and post-event feedback adjustments, lacking online, real-time, and hierarchical fine-grained judgment capabilities. When local anomalies are masked by overall average data, the system cannot identify and intervene at the moment the defect occurs, and can only perform "post-event judgment" through performance testing after the pressing is completed, which still cannot avoid the problem of material waste due to judgment lag. Summary of the Invention

[0005] To address the aforementioned problems in existing technologies, this invention provides a high-precision hot-pressing process for capacitive touchscreens. Through a differentiated sensor layout and a three-layer progressive intelligent judgment logic, precise data monitoring of key pressing areas is achieved; this solves the problems of unstable pressing quality and yield fluctuations caused by uneven pressure and temperature distribution in existing capacitive touchscreen hot-pressing processes.

[0006] The objective of this invention can be achieved through the following technical solutions: A high-precision hot-pressing process for capacitive touchscreens includes the following steps: Step 1: Define and mark the critical monitoring areas and non-critical monitoring areas in the hot press head, pressure platform, qualified glass panel, and target flexible printed circuit board, respectively; Step 2: Embed miniature temperature sensor arrays and miniature pressure sensor arrays in the hot pressing head and the pressure bearing platform respectively to establish the hot pressing surface and the pressure bearing surface, and ensure that the sensor deployment density in the key monitoring area is higher than that in the non-key area; Step 3: Place the qualified glass panel and the target flexible printed circuit board on the hot pressing surface and the pressure bearing surface respectively, and ensure that the calibrated key monitoring areas correspond to the non-key monitoring areas; Step 4: Perform the hot pressing process, and set up multiple continuous process monitoring nodes during the linear pressing stage; at each process monitoring node, synchronously collect and record the full-field data of the micro temperature sensor array and the micro pressure sensor array; based on the comparison between the collected full-field data and the full-field data of the process monitoring nodes recorded in the preset data model, perform triple monitoring and judgment in sequence. Step 5: The linear pressure reduction phase ends. Based on the results of the triple monitoring, determine whether to perform subsequent pressure holding and cooling operations.

[0007] As a further aspect of the present invention, in step four, the triple monitoring and judgment order executed sequentially is overall correspondence judgment, partition correspondence judgment, and point-to-point correspondence judgment.

[0008] As a further aspect of the present invention, in step four, the preset data model is generated by training the full-field temperature and pressure distribution data collected from qualified products produced under standard process conditions. The data model includes the overall, zone, and key point theoretical temperature and pressure data corresponding to each monitoring node, and has a corresponding error threshold.

[0009] As a further aspect of the present invention, the overall correspondence determination specifically involves: calculating the average temperature and average pressure of the entire pressing surface of the current node, and determining whether they fall within the overall temperature-pressure threshold range preset for the node in the data model.

[0010] As a further aspect of the present invention, in the partition correspondence determination, the partition correspondence determination specifically involves: for each predefined key monitoring area, calculating its regional average temperature and regional average pressure, and determining whether it falls within the preset partition temperature-pressure threshold range for that node and that area in the data model.

[0011] As a further aspect of the present invention, the point-to-point correspondence determination specifically involves: checking the single-point readings of the corresponding micro temperature sensors and micro pressure sensors within the key monitoring area one by one, and determining whether they exceed the single-point temperature-pressure threshold preset for the node and the point in the data model.

[0012] As a further aspect of the present invention, in step one, the critical monitoring area includes at least one of the four-sided frame sealing area of ​​the glass panel, the pin crimping area of ​​the integrated circuit on the flexible printed circuit board, and the interface area of ​​each connector, while the rest are non-critical monitoring areas.

[0013] As a further aspect of the present invention, in step four, if any node fails any judgment in the triple monitoring judgment, the system triggers an early warning and suspends the hot pressing process.

[0014] As a further aspect of the present invention, in step five, if the product is determined to be defective, the system will record event information including the location of the abnormal node, the level of failure, and specific deviation data for quality traceability and process optimization.

[0015] As a further aspect of the present invention, the overall correspondence determination, the partition correspondence determination, and the point-to-point correspondence determination follow a sequential and irreversible determination logic.

[0016] The beneficial effects of this invention are as follows: By employing a three-tiered progressive judgment logic of "overall → zone → point-to-point," the quality control node is moved from the final inspection to the linear pressing stage of the hot-pressing process. Real-time judgment and process pause are implemented at the critical moment when defects occur, fundamentally preventing the generation of batch defective products. Simultaneously, for critical areas determining product reliability, such as the frame and IC pins, a high-density sensor layout and independently set strict thresholds ensure that these areas are always within the optimal process window. This directly solves the hidden dangers of poor sealing, cold solder joints, and pin breakage caused by uneven local pressure or temperature in traditional processes, significantly improving product consistency and long-term reliability. Attached Figure Description

[0017] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the accompanying drawings.

[0018] Figure 1 This is a flowchart of the linear compression stage of the present invention; Detailed Implementation

[0019] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided.

[0020] refer to Figure 1 This invention provides a high-precision hot-pressing process for capacitive touchscreens. Through differentiated sensor layout and a three-layer progressive intelligent judgment logic, it achieves precise data monitoring of key pressing areas. This solves the problems of unstable pressing quality and yield fluctuations caused by uneven pressure and temperature distribution in existing capacitive touchscreen hot-pressing processes. The process includes the following steps: Step 1: Define and calibrate critical and non-critical monitoring areas in the hot press head, pressure platform, qualified glass panel, and target flexible printed circuit board (FPC). Pre-define and precisely calibrate critical and non-critical monitoring areas on the hot press head, pressure platform, qualified glass panel, and target FPC. Critical monitoring areas include, but are not limited to: the sealing area around the four edges of the glass panel, the pin crimping area of ​​the integrated circuit (IC) on the FPC, and the interface areas of each connector. The remaining areas are defined as non-critical monitoring areas. By calibrating critical and non-critical monitoring areas, and considering both high precision requirements and the cost of comprehensive deployment, precise monitoring of critical areas can be achieved while effectively controlling costs.

[0021] Step 2: Embed miniature temperature sensor arrays and miniature pressure sensor arrays in the hot press head and pressure bearing platform respectively to establish the hot press surface and pressure bearing surface, and ensure that the sensor deployment density in the key monitoring area is higher than that in the non-key area; thus forming a differentiated miniature sensor array. In detail, miniature temperature sensor arrays and miniature pressure sensor arrays are embedded in the working surfaces of the hot press head and the pressure platform, respectively, to form intelligent hot press surfaces and intelligent pressure surfaces that can sense the distribution of physical fields, relying on existing technologies. The sensor arrays are deployed according to the principle of "high density in critical areas and low density in non-critical areas" to ensure that the monitoring resolution of critical areas is much higher than that of non-critical areas. The sensor data is led out to the real-time monitoring system through shielded flexible lines to ensure stable signal transmission under high temperature and high pressure conditions.

[0022] Step 3: Workpiece alignment and area mapping; Place the qualified glass panel and the target flexible printed circuit board on the hot pressing surface and the pressure bearing surface respectively, and ensure that the calibrated key monitoring areas correspond to the non-key monitoring areas; Specifically, place the qualified glass panel and the target FPC between the intelligent hot pressing surface and the intelligent pressure bearing surface respectively; Through a vision system or mechanical positioning reference, ensure that the calibrated key monitoring areas on the glass panel and FPC correspond precisely in space to the high-density deployment area in the equipment sensor array, forming an accurate mapping relationship from the "workpiece design area" to the "equipment sensing unit".

[0023] Step 4: Perform the hot pressing process, establishing multiple continuous process monitoring nodes during the linear depressurization phase. At each monitoring node, synchronously collect and record full-field data from the miniature temperature sensor array and the miniature pressure sensor array. Based on the comparison between the collected full-field data and the full-field data of the process monitoring nodes recorded in the preset model, perform triple monitoring and judgment sequentially. Specifically, during the critical linear depressurization phase, establish multiple continuous process monitoring nodes (such as time nodes or depressurization displacement nodes). At each node, synchronously collect and record full-field temperature and pressure data from all sensors.

[0024] It should also be noted that the data model preset in the equipment system is generated by training on the overall temperature and pressure distribution data collected from qualified products under the same standard process conditions. This data model includes overall data corresponding to each monitoring node. The overall data first includes overall corresponding judgment data, the overall theoretical temperature and pressure data and mapping relationship of the hot-pressing surface and the pressure-bearing surface; secondly, zonal judgment data, the overall theoretical temperature and pressure data and mapping relationship of the monitoring key area and the non-monitoring key area; and finally, key point judgment data, the theoretical temperature and pressure data for the frame sealing area, the IC pin crimping area on the FPC, and the interface areas of each connector. It should also be noted that the overall corresponding judgment data, zonal judgment data and key point judgment data in each monitoring node can all be set with error thresholds that conform to the process standards. By using preset threshold ranges for constraint, process stability is ensured.

[0025] At each monitoring node, the system compares the measured data across the entire field with the preset model data, sequentially performing overall consistency judgment, zoning compliance judgment, and key point accuracy judgment. If all three judgments pass, the system proceeds to the next node; if any fails, an alarm is triggered and pressure is suspended, achieving closed-loop control. When all monitoring nodes have completed the three judgments without any abnormalities, the system automatically enters the pressure holding and curing stage, maintaining the set temperature and pressure until the end of the process cycle. If an alarm is triggered at any node, the operation interface will display the location of the abnormal area, the type of deviation parameter, and suggested handling measures in real time.

[0026] Overall correspondence determination: Calculate the average temperature T and average pressure P of the entire pressing surface at the current node, and determine whether (T\P) falls within the threshold data range of this node in the data model; if it is not within the threshold, it is determined that the overall heating has failed and the main pressure is abnormal, so as to quickly screen major process deviations at the equipment level and system level and avoid batch defects caused by equipment failure; if it is within the threshold range, it proceeds to the corresponding judgment of the partition.

[0027] Partition correspondence determination: Based on the preset partition mapping relationship, the key point determination focuses on core parts such as the frame sealing area and the IC pin crimping area on the FPC. It extracts the measured average temperature and pressure of key and non-key areas, and calculates the regional average temperature and regional average pressure of each key monitoring area (such as the upper left frame area and IC area) at the current node. It determines whether the (regional average temperature and regional average pressure) of each key area falls within the node partition threshold range of the more stringent data model preset for that area. This ensures that all functional key parts are in the optimal process environment and prevents local "undervoltage" or "overheating". If the key areas are all within the node partition threshold range of the data model, the system proceeds to precise key point determination. If they are not within the threshold range, it is determined that there is a risk of local defects, the system marks the abnormal area and suspends the pressing process. This avoids poor connection caused by local overvoltage or undervoltage and solves quality problems such as poor frame sealing, FPC cold solder joints or IC pin breakage.

[0028] Point-to-point correspondence determination: The system checks the real-time readings of each sensor point within the key monitoring area and the corresponding key monitoring area one by one; this is used to detect distribution anomalies, such as miniature temperature and pressure sensors on the coaxial line; by checking whether the collected and recorded single-point readings exceed the allowable threshold for single miniature temperature and pressure sensors on the coaxial line in the data model node, if they are not within the threshold, the point is determined to be abnormal, the system automatically marks the specific sensor location and triggers the corresponding zone warning and the corresponding single-point sensor location; if all key points are within the threshold range, the node is determined to have passed all three judgments and is allowed to enter the next process stage; the sensor data through single-point judgment further verifies the process stability, eliminates micro-area anomaly interference, solves extreme anomaly point problems caused by small foreign objects, local material unevenness, or sensor failure, and ensures the uniformity of distribution.

[0029] Step 5: After the linear pressing phase ends, based on the triple monitoring results, determine whether to perform subsequent pressure holding and cooling operations. Specifically, the hot pressing process includes linear pressing, pressure holding, and cooling stages. Based on the final judgment results of the triple monitoring output of all nodes in Step 4, if all three levels of judgment at all nodes pass, the capacitive touchscreen product is determined to be a qualified product. If any node fails at any judgment level (overall, partition, or point-to-point), the abnormal event is immediately recorded (including node location, failure level, and specific data), and the product is determined to be a non-qualified product. This record is used for subsequent quality traceability, root cause analysis, and process optimization.

[0030] As described above, real-time pressure and temperature monitoring is implemented during the linear pressing stage of the capacitive touchscreen hot-pressing process. A three-tiered progressive judgment logic—"overall → zone → point-to-point"—shifts quality control from final result inspection to the core stage of the production process (linear pressing). Judgments are made and "pause" commands are executed at the instant irreversible defects occur, achieving full-dimensional process interception from macro to micro levels. This fundamentally avoids the generation of batch defective products. Simultaneously, for critical areas determining product lifespan and reliability, such as frame sealing and IC pin connections, high-density sensing and independent, stringent threshold judgments ensure these "quality fortresses" remain within the optimal process window. This directly solves typical hidden dangers in traditional processes, such as poor frame sealing, FPC soldering defects, and IC pin stress fracture, significantly improving product consistency and long-term reliability. Furthermore, all node and field data and judgment results generated during product production can be completely recorded and stored in a linked manner. This provides a traceable "digital fingerprint" for subsequent processes, facilitating quality traceability and root cause analysis, and providing reference data for subsequent process optimization.

[0031] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A high-precision hot-pressing process for capacitive touchscreens, characterized in that: Includes the following steps: Step 1: Define and mark the critical monitoring areas and non-critical monitoring areas in the hot press head, pressure platform, qualified glass panel, and target flexible printed circuit board, respectively; Step 2: Embed miniature temperature sensor arrays and miniature pressure sensor arrays in the hot pressing head and the pressure bearing platform respectively to establish the hot pressing surface and the pressure bearing surface, and ensure that the sensor deployment density in the key monitoring area is higher than that in the non-key area; Step 3: Place the qualified glass panel and the target flexible printed circuit board on the hot pressing surface and the pressure bearing surface respectively, and ensure that the calibrated key monitoring areas correspond to the non-key monitoring areas; Step 4: Perform the hot pressing process, and set up multiple continuous process monitoring nodes during the linear pressing stage; at each process monitoring node, synchronously collect and record the full-field data of the micro temperature sensor array and the micro pressure sensor array; Based on the comparison between the collected full-field data and the full-field data of the process monitoring nodes recorded in the preset data model, the triple monitoring judgment is performed in sequence; Step 5: The linear pressure reduction phase ends. Based on the results of the triple monitoring, determine whether to perform subsequent pressure holding and cooling operations.

2. The high-precision hot-pressing process for capacitive touchscreens according to claim 1, characterized in that: In step four, the triple monitoring judgment is executed in the following order: overall correspondence judgment, zone correspondence judgment, and point-to-point correspondence judgment.

3. The high-precision hot-pressing process for capacitive touchscreens according to claim 2, characterized in that: In step four, the preset data model is generated by training the temperature and pressure distribution data of qualified products produced under standard process conditions. The data model includes the overall, zone and key point theoretical temperature and pressure data corresponding to each monitoring node, and has corresponding error thresholds.

4. The high-precision hot-pressing process for capacitive touchscreens according to claim 3, characterized in that: The overall correspondence determination specifically involves: calculating the average temperature and average pressure of the entire pressing surface of the current node, and determining whether they fall within the overall temperature-pressure threshold range preset for the node in the data model.

5. The high-precision hot-pressing process for capacitive touchscreens according to claim 4, characterized in that: The partition determination is specifically as follows: for each predefined key monitoring area, calculate its regional average temperature and regional average pressure, and determine whether it falls within the pre-defined partition temperature-pressure threshold range for that node and that area in the data model.

6. The high-precision hot-pressing process for capacitive touchscreens according to claim 5, characterized in that: The point-to-point correspondence determination specifically involves checking the single-point readings of the corresponding miniature temperature sensors and miniature pressure sensors within the key monitoring area one by one, and determining whether they exceed the single-point temperature-pressure threshold preset for that node and that point in the data model.

7. The high-precision hot-pressing process for capacitive touchscreens according to claim 1, characterized in that: In step one, the critical monitoring areas include the sealing area around the four edges of the glass panel, the pin crimping area of ​​the integrated circuit on the flexible printed circuit board, and the interface areas of each connector; the rest are non-critical monitoring areas.

8. The high-precision hot-pressing process for capacitive touchscreens according to claim 2, characterized in that: In step four, if any node fails any of the three-stage monitoring decisions, the system will trigger an early warning and suspend the hot-pressing process.

9. The high-precision hot-pressing process for capacitive touchscreens according to claim 6, characterized in that: In step five, if a product is determined to be non-conforming, the system will record event information including the location of the abnormal node, the level of failure, and specific deviation data, for quality traceability and process optimization.

10. The high-precision hot-pressing process for capacitive touchscreens according to claim 2, characterized in that: The overall correspondence determination, the partition correspondence determination, and the point-to-point correspondence determination follow a sequential and irreversible determination logic.

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