Glass substrate re-inspection real-time focus correction device, system and method

Abstract

The present application relates to the technical field of display panel manufacturing, and in particular to a glass substrate re-inspection real-time focusing correction device, system and method; through the integrated structure of a temperature sensor network, a focusing detection unit, a control unit and a lens adjusting mechanism, the light spot gray data reflected by the glass substrate and the temperature field distribution data of the mounting base can be obtained online and in real time, after rapid calculation by the control unit, the lens adjusting mechanism is driven to correct the height when the net defocus exceeds the standard, the dynamic response time is not more than 45 ms, and it is suitable for the speed production line rhythm; the focusing error is eliminated through a multi-dimensional compensation algorithm combined with the temperature field distribution data, the risk of missed detection is greatly reduced, the influence of vibration and deformation of the glass substrate in the transmission process on focusing is effectively overcome, the technical problem that the existing system cannot match the speed production line rhythm due to long response time is solved, and the focusing precision is improved to meet the defect detection requirement.

Description

Technical Field

[0001] This invention relates to the field of display panel manufacturing technology, and specifically to a real-time focusing correction device, system and method for glass substrate re-inspection. Background Technology

[0002] In the manufacturing process of flat panel display devices, the surface quality inspection of glass substrates is a key step to ensure product yield. Automatic optical inspection and re-inspection machines need to perform high-magnification and accurate re-inspection of suspected defects found in the initial inspection. The imaging quality is directly affected by the focusing accuracy. A focusing deviation of more than 0.5μm may lead to the missed detection of micro-defects.

[0003] Existing focusing systems used in the inspection of large-size glass substrates of G8.5 generation and above have several technical defects and cannot meet the actual needs of production lines: First, glass substrates experience micro-vibrations with an amplitude of ±15μm and thermal deformation of ±60μm or more during transport. The response time of traditional focusing systems is generally greater than 200ms, making it difficult to match the high-speed production line cycle of 3m / min or more, and easily resulting in focusing lag; Second, within the large-size inspection range of 2500mm×3000mm, due to optical system aberrations and substrate support deformation, it is difficult to guarantee the focusing consistency between the edge and center areas. The differences often exceed ±5μm, making it impossible to achieve accurate detection across the entire area. In addition, the glass substrate is transparent, and the multiple reflection signals generated by the detection laser on its front and back surfaces will increase the error in the defocus calculation by more than 30%. Existing technologies lack effective signal separation and interference cancellation mechanisms. Finally, the existing calibration process relies on manual replacement of standard targets, and a single calibration takes more than 30 minutes, resulting in low calibration efficiency and seriously affecting the overall utilization rate of the equipment. Existing focusing detection solutions are slow to respond, have low accuracy, poor consistency across the entire area, and are cumbersome to calibrate, making it difficult to meet the actual needs of high-speed and high-precision re-inspection of large-size glass substrates. Summary of the Invention

[0004] The purpose of this invention is to provide a real-time focusing correction device, system and method for glass substrate re-inspection, which solves the technical problems of slow focusing response and low accuracy in the re-inspection of large-size glass substrates.

[0005] The solution of the present invention to the above-mentioned technical problems is as follows: A real-time focusing correction device for glass substrate re-inspection includes: The mounting base is located on the glass substrate transport platform; a temperature sensor network is installed inside the mounting base to acquire temperature field distribution data of the mounting base. The focusing detection unit is used to emit a detection laser to the glass substrate and acquire the grayscale data of the light spot reflected by the glass substrate, and to preliminarily calculate the original defocusing amount based on the grayscale data of the light spot. The control unit is used to obtain the net defocus amount through a multi-dimensional compensation algorithm based on the original defocus amount and temperature field distribution data. When the net defocus amount exceeds the preset threshold, a piezoelectric drive voltage command is sent based on the net defocus amount. A lens adjustment mechanism is used to adjust the height of the lens mount along its axial direction according to a piezoelectric drive voltage command.

[0006] Further specifying, the focusing detection unit includes a coaxial laser sensor, a beam splitter, and a spot image processor; The coaxial laser sensor is used to emit detection laser, and the coaxial laser sensor is arranged on the periphery of the beam splitter perpendicular to the axis of the lens mount. The beam splitter is located between the lens carrier and the glass substrate transmission platform. The beam splitter is used to refract the detection laser to the detection point on the glass substrate and to guide the detection laser reflected by the glass substrate into the spot image processor. The light spot image processor is located inside the lens mount and is coaxially arranged with the lens mount. The light spot image processor is located above the main inspection objective lens. The light spot image processor acquires the mixed light spot grayscale data of the front and rear surfaces of the glass substrate through the built-in photosensitive array, quickly identifies and removes the reflection signal interference of the front and rear surfaces of the glass substrate through the grayscale threshold segmentation algorithm, and uses the phase difference to calculate the original defocus amount.

[0007] Further specifying, the control unit includes: The material compensation module uses a Monte Carlo simulation model to correct the optical path of the original defocus amount based on the preset thickness and corresponding refractive index of the current glass substrate, and obtains the material-compensated defocus amount. The temperature gradient compensation module combines temperature field distribution data to run a temperature gradient compensation algorithm, calculates the deformation of the mounting base caused by thermal expansion, and compensates for the material defocusing amount based on the deformation of the mounting base to obtain the temperature-compensated defocusing amount. The warp and vibration suppression module is used to fit the three-dimensional curved surface of the glass substrate through an edge warp compensation algorithm, and then filter the mechanical vibration noise generated during the transmission of the glass substrate through an adaptive Kalman filter algorithm to obtain the net defocus amount. The instruction generation module compares the obtained net defocus amount with a preset threshold. If the net defocus amount exceeds the preset threshold, it generates a corresponding piezoelectric drive voltage instruction based on the net defocus amount.

[0008] Further specified, a calibration target is installed on the mounting base via a quick-release buckle, and the calibration target is coaxially arranged with the main inspection objective lens; The control unit also includes: The self-test module is used to obtain the status of the glass substrate transmission platform in real time. If the glass substrate transmission platform meets the calibration conditions, it will perform self-testing in conjunction with the calibration target through the temperature sensor network, focusing detection unit, material compensation module and temperature gradient compensation module respectively.

[0009] Further specifying, the lens adjustment mechanism includes a piezoelectric ceramic actuator assembly and a flexible hinge; The piezoelectric ceramic actuator is connected to the lens carrier via a flexible hinge, and the lens carrier is slidably connected to the guide assembly along its axial direction. The piezoelectric ceramic actuator generates nanoscale stretching and deformation based on the inverse piezoelectric effect according to the piezoelectric drive voltage command after D / A conversion and high voltage amplification, and drives the lens carrier to move through the flexible hinge.

[0010] Further specifying, the calibration target is selected as a fused silica glass target, and the coefficient of thermal expansion of the fused silica glass target is ≤0.33×10⁻⁶. -6 / ℃.

[0011] Further specified, the coaxial laser sensor emits a detection laser with a wavelength of 650nm±10nm, and the power of the detection laser is 5mW±0.5mW; the transmittance of the beam splitter for the 650nm wavelength laser is ≥90%.

[0012] Further specified, the guide component is a ball bearing guide sleeve, the linearity of the guide component movement is ≤0.1μm / mm, the displacement resolution of the piezoelectric ceramic actuator is ≤0.5nm, and the resonant frequency of the flexible hinge is ≥2kHz.

[0013] A real-time focusing correction system for glass substrate re-inspection includes a main control unit, multiple real-time focusing correction devices for glass substrate re-inspection, and slave control units that correspond one-to-one with the real-time focusing correction devices for glass substrate re-inspection. Multiple glass substrate re-inspection real-time focusing correction devices are arrayed along the detection area of ​​the glass substrate transfer platform. The slave control unit is mounted on the mounting base and communicates with the control unit. All of the slave control units communicate with the master control unit. The master control unit sends synchronization commands to all slave control units, and the slave control units upload the net defocus amount and correction results at the corresponding positions of the glass substrate to the master control unit.

[0014] A real-time focusing correction method for glass substrate re-inspection, based on the aforementioned real-time focusing correction device for glass substrate re-inspection, includes the following steps: Obtain temperature field distribution data of the mounting base; A detection laser is emitted toward a glass substrate, and the grayscale data of the light spot reflected from the glass substrate is acquired. The initial defocusing amount is calculated based on the grayscale data of the light spot. The net defocus amount is obtained by combining the original defocus amount and temperature field distribution data with a multi-dimensional compensation algorithm. The net defocus amount is compared with a preset threshold. When the net defocus amount exceeds the preset threshold, a piezoelectric drive voltage command is sent based on the net defocus amount. The lens mount is adjusted and corrected according to the piezoelectric drive voltage command to adjust the height of its axial direction. Reacquire the net defocus amount and determine if it meets the correction value. If yes, end the process; otherwise, continue the correction.

[0015] The beneficial effects of this invention are as follows: 1. This invention, through the integrated structure of a temperature sensor network, a focusing detection unit, a control unit, and a lens adjustment mechanism, can acquire online real-time grayscale data of the light spot reflected from the glass substrate and temperature field distribution data of the mounting base. After rapid calculation by the control unit, the lens adjustment mechanism is driven to perform height correction when the net defocus amount exceeds the standard. The dynamic response time does not exceed 45ms, which is suitable for high-speed production lines with a cycle time of 3m / min or higher. Combining the temperature field distribution data, a multi-dimensional compensation algorithm is used to eliminate focusing errors, so that the net defocus amount calculation error is ≤0.05μm and the focusing accuracy does not exceed 0.3μm. The detection rate of 0.4μm micro-scratches is increased from 78% to over 96%, which significantly reduces the risk of missed detection. It effectively overcomes the influence of vibration and deformation of the glass substrate during transportation on focusing, solves the technical problem that the existing system cannot match the cycle time of high-speed production lines due to long response time, and improves focusing accuracy to meet the needs of defect detection.

[0016] 2. This invention, by arraying a real-time focusing correction device for glass substrate re-inspection in the detection area of ​​the glass substrate transmission platform, can fully cover the detection area of ​​an ultra-large glass substrate of 3370mm×2940mm; in conjunction with the main control unit and the slave control unit, synchronous correction control is achieved, which facilitates the construction of a full-surface focusing topography map, coordinates the correction actions of adjacent devices, and ensures that the focusing consistency difference within the detection range is ≤±0.35μm, meeting the full-area accurate detection requirements of large-size glass substrates of G8.5 generation and above.

[0017] 3. This invention uses a self-testing module to determine self-testing conditions. By performing self-testing operations, the self-testing deviation threshold is precisely controlled within 0.1μm, reducing the daily maintenance and calibration time of the equipment from the traditional 2 hours to 72 seconds, and increasing the effective operating rate of the equipment by 17%. According to actual production line verification, it can reduce the loss of defective products by approximately 480,000 yuan per month.

[0018] 4. This invention adopts a combination structure of piezoelectric ceramic actuator guide assembly and flexible hinge, with displacement resolution ≤0.5nm, enabling nanometer-level precise adjustment; the flexible hinge eliminates lateral force interference, and the ball bearing guide sleeve ensures that the main inspection objective lens on the lens carrier moves in a pure linear motion along the Z-axis, with a motion straightness ≤0.1μm / mm, and the flexible hinge resonant frequency ≥2kHz, which still has excellent structural stability under high-frequency operating conditions in high-speed production lines. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the real-time focusing correction device for glass substrate re-inspection of the present invention; Figure 2 This is a schematic diagram of the real-time focusing correction device for glass substrate re-inspection of the present invention. Figure 3 This is a timing diagram of the real-time focusing correction device for glass substrate re-inspection of the present invention; Figure 4 This is a schematic diagram of the real-time focusing correction system for glass substrate re-inspection of the present invention; Figure 5 The figure shows the test results of the response characteristics of the real-time focusing correction system for glass substrate re-inspection according to the present invention.

[0020] In the diagram, 1-Mounting base; 2-Coaxial laser sensor; 3-Spot image processor; 4-Piezoelectric ceramic actuator; 5-Lens carrier; 6-Guiding assembly; 7-Control unit; 8-Quick-release interface; 9-Beam splitter; 10-Main inspection objective lens; 11-Calibration target; 12-Flexible hinge; 13-Main control unit; 14-Slave control unit; 15-Communication bus; 16-Temperature monitoring sensor; 17-Glass substrate transmission platform. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0023] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0024] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0025] Example 1 refer to Figure 1 The present invention provides a real-time focusing correction device for glass substrate re-inspection, including a mounting base 1, a focusing detection unit, a control unit 7, and a lens adjustment mechanism.

[0026] Mounting base 1 is set on glass substrate transport platform 17, which is used to transport glass substrates. Mounting base 1 is equipped with an 8-channel distributed temperature sensor network with a temperature measurement accuracy of ±0.1℃ and a sampling frequency of 100Hz. It is used to acquire temperature field distribution data of mounting base 1 in the whole area and at high frequency, so as to provide accurate basic data for subsequent temperature gradient compensation.

[0027] The focusing detection unit emits a detection laser to the glass substrate and acquires the grayscale data of the light spot reflected by the glass substrate. The grayscale data is used to preliminarily calculate the original defocus amount. Since the glass substrate is transparent, the detection laser will generate reflected light signals on the front and rear surfaces of the glass substrate and reflect them along the optical axis of the main detection objective lens 10. Thus, the acquired grayscale data of the light spot contains a mixed light spot signal containing the overlap information of the front and rear surfaces.

[0028] The control unit 7 is communicatively connected to the temperature sensor network and the focus detection unit. The control unit 7 acquires the original defocus amount and temperature field distribution data in a low-latency manner through shielded wires, and obtains the current net defocus amount by combining the original defocus amount and temperature field distribution data with a multi-dimensional compensation algorithm. When the net defocus amount exceeds a preset threshold, a piezoelectric drive voltage command is sent according to the magnitude of the net defocus amount. The preset threshold for the net defocus amount is in the range of 0.1~0.5μm. When the net defocus amount does not exceed the preset threshold, the current state can be maintained.

[0029] The lens adjustment mechanism is detachably connected to the mounting base 1 via a quick-release interface 8. The quick-release interface 8 conforms to the annular flange structure of ISO 10285 standard. Both the focusing detection unit and the lens adjustment mechanism are connected to the mounting base 1 via X / Y axis adjusting arms, which are used to move to the corresponding position for re-inspection based on the upstream coarse inspection results. The lens adjustment mechanism is communicatively connected to the control unit 7. The lens adjustment mechanism adjusts the height of the lens carrier 5 in its axial direction according to the piezoelectric drive voltage command, and synchronously drives the height of the main inspection objective lens 10, converting digital commands into physical displacement to complete the focusing correction.

[0030] To further explain, the focusing detection unit includes a coaxial laser sensor 2, a beam splitter 9, and a spot image processor 3.

[0031] The coaxial laser sensor 2 is used to emit a detection laser. The detection laser is preferably a linearly polarized laser with a wavelength of 650nm±10nm and a power that is stable at 5mW±0.5mW to improve detection accuracy. The axis of the coaxial laser sensor 2 is set on the periphery of the beam splitter 9 and connected to the lens carrier 5.

[0032] The beam splitter 9 is located between the lens carrier 5 and the glass substrate transmission platform 17. The beam splitter 9 is used to refract the detection laser emitted by the coaxial laser sensor 2 onto the detection point on the glass substrate so that it is coaxially coupled with the main detection objective lens 10 at the bottom of the lens carrier 5. The glass substrate reflects the detection laser, and the reflected detection laser returns along the original path through the beam splitter 9 and is then introduced into the spot image processor 3. The beam splitter 9 has a transmittance of ≥90% and a reflectivity of ≤5% for 650nm wavelength laser.

[0033] The light spot image processor 3 is located inside the lens mount 5 and coaxially arranged with the lens mount 5, and is located above the main inspection objective lens 10. The light spot image processor 3 acquires the mixed light spot grayscale data of the front and rear surfaces of the glass substrate through the built-in photosensitive array, has a pre-stored glass surface reflection characteristic compensation model, quickly identifies and removes the reflection signal interference of the front and rear surfaces of the glass substrate through the grayscale threshold segmentation algorithm, and uses the phase difference to calculate the initial defocus amount, and then transmits the initial defocus amount to the control unit 7. The initial defocus amount calculation process is processed by the FPGA front end of the control unit 7, which takes ≤1.5ms, ensuring the real-time performance of the detection data.

[0034] For further explanation, please refer to Figure 2 The control unit 7 includes: The material compensation module is used to correct the optical path of the original defocus amount using a Monte Carlo simulation model based on the preset thickness and corresponding refractive index parameters of the current glass substrate, so as to obtain the material-compensated defocus amount.

[0035] The preset thickness and corresponding refractive index parameters of the glass substrate can be pre-stored. For example, the preset thickness of the glass substrate is 0.3mm~1.1mm, and the corresponding refractive index is 1.51~1.53. The original defocus amount is corrected by using a Monte Carlo simulation model to eliminate the calculation error caused by the difference in glass material.

[0036] The temperature gradient compensation module is used to run a temperature gradient compensation algorithm in conjunction with temperature field distribution data, calculate the deformation of the mounting base caused by thermal expansion, and compensate for the material defocusing amount based on the base deformation, with an accuracy of ±0.05μm / ℃, to obtain the temperature-compensated defocusing amount.

[0037] The warpage and vibration suppression module, when in dynamic detection mode (i.e., when the glass substrate transmission platform 17 is running normally and requires re-inspection), fits the three-dimensional curved surface of the glass substrate through an edge warpage compensation algorithm to adapt to a warpage of ≤60μm. It also filters out the mechanical vibration noise generated during the transmission of the glass substrate through an adaptive Kalman filter algorithm, achieving a suppression rate of ≥92% for amplitudes of ±15μm. Finally, it obtains the net defocus amount, with a calculated error of ≤0.05μm for the actual defocus amount.

[0038] The instruction generation module, after multi-dimensional compensation, compares the obtained net defocus amount with a preset threshold. If the net defocus amount exceeds the preset threshold, it generates a corresponding piezoelectric drive voltage instruction based on the net defocus amount.

[0039] The control unit 7 adopts an FPGA+ARM heterogeneous computing architecture, configuring the algorithms involved in the compensation process in the algorithm library, which can be called when needed. It is equipped with dual communication interfaces of PROFINET and EtherCAT, which are connected to the focus detection unit, temperature sensor network and lens adjustment mechanism respectively. The material compensation module, temperature gradient compensation module, warpage and vibration suppression module and instruction generation module are processed in the ARM core of the control unit 7. The net defocus amount multi-dimensional compensation calculation and instruction generation time is about 17ms, and the total time from self-correction start is ≤19.5ms, ensuring the rapid generation of control instructions.

[0040] To further explain, the lens adjustment mechanism includes a piezoelectric ceramic actuator 4, a guide assembly 6, and a flexible hinge 12.

[0041] The piezoelectric ceramic actuator 4 adopts a three-layer stacked amplification structure with a displacement resolution ≤0.5nm, a maximum stroke ≥100μm, and a drive response time ≤5ms. The piezoelectric ceramic actuator 4 can convert electrical signals into nanoscale mechanical expansion and contraction deformation based on the inverse piezoelectric effect. The expansion and contraction end of the piezoelectric ceramic actuator 4 is rigidly connected to the side wall of the lens carrier 5 through a flexible hinge 12. The flexible hinge adopts an integrated cross-shaped structure, which can effectively transmit the expansion and contraction deformation of the piezoelectric ceramic actuator 4, while eliminating lateral force interference and preventing the lens carrier 5 from tilting. The resonant frequency of the flexible hinge 12 is ≥2kHz, which improves the structural stability under high-frequency operating conditions.

[0042] The lens carrier 5 is slidably engaged with the guide component 6, which is vertically fixed to the mounting base 1. The guide component 6 can be a ball bearing sleeve. The linearity of the guide component 6 is ≤0.1μm / mm, ensuring that the lens carrier 5 moves in a pure straight line along the Z-axis without any offset error.

[0043] The lower end of the quick-release interface 8 is fixedly connected to the mounting base 1, and the upper end of the quick-release interface 8 is bolted to the overall base of the lens adjustment mechanism, making disassembly and assembly convenient and facilitating the later maintenance and repair of the equipment. The control unit 7 can be optionally embedded in the inner cavity of the quick-release interface 8. The lens carrier 5 passes through the central through hole of the quick-release interface 8 and cooperates with the guide component 6, making the overall structure of the device compact and space utilization efficient.

[0044] Preferred, Reference Figure 3 After the position of the main inspection objective 10 changes, the focal plane of the main inspection objective 10 is adjusted accordingly. The time from receiving the piezoelectric drive voltage command to completing the focus correction is about 20.5ms, and the total time from the start of the correction to the completion of the focus correction action is ≤40ms.

[0045] Preferably, the control unit 7 further includes a closed-loop verification module, which is used to re-obtain the net defocus amount through the temperature sensor network, the focus detection unit, and the control unit 7 after completing a single correction action, and compare the current net defocus amount with a preset verification threshold for confirmation. If the verification threshold is exceeded, the correction action continues until the defocus amount converges to an allowable range, for example, the net defocus amount is ≤0.3μm; if the correction threshold is not exceeded, the correction is completed. The closed-loop verification confirmation takes ≤5ms, so the total time from the start of correction to the closed-loop verification confirmation is ≤45ms.

[0046] To further explain, a temperature monitoring sensor 16 is installed on the mounting base 1. The temperature monitoring sensor 16 is close to the glass substrate to detect the surface temperature of the glass substrate in real time.

[0047] At this time, the control unit 7 also includes a protection module, which is used to obtain the surface temperature of the glass substrate in real time through the temperature monitoring sensor 16. By comparing it with the preset safe temperature of 60°C, when the surface temperature of the glass substrate is detected to be ≥60°C, a high temperature warning is immediately triggered and the detection is suspended. The detection is restarted after the production line temperature control parameters are adjusted and the glass substrate temperature returns to normal, so as to avoid the substrate thermal deformation caused by high temperature from affecting the focusing accuracy.

[0048] To further explain, a target mounting position is provided on the side of the mounting base 1. This position is used to mount the calibration target 11. The calibration target 11 is detachably fixed to the target mounting position via a quick-release clip structure. When self-calibration is required, the focusing detection unit and lens adjustment mechanism move to the target mounting position via the X / Y axis adjustment arm, ensuring that the calibration target 11 is coaxially aligned with the main detection objective lens 10, thus guaranteeing the consistency of the self-calibration reference. The calibration target 11 is made of a material with a low coefficient of thermal expansion, such as Invar or microcrystalline glass, with a coefficient of thermal expansion ≤ 1.5 × 10⁻⁶. -6 / ℃, Calibration target 11 is illustrated using fused silica glass as an example. The thermal expansion coefficient of fused silica glass target is ≤0.33×10. -6 / ℃, possessing excellent low thermal expansion characteristics, can effectively avoid the influence of ambient temperature changes on the calibration benchmark, ensuring the accuracy of self-test calibration.

[0049] Control unit 7 also includes: The self-test module is used to obtain the status of the glass substrate transmission platform 17. If the glass substrate transmission platform 17 meets the calibration conditions, it will automatically calibrate the target 11 in conjunction with the temperature sensor network, the focusing detection unit, the material compensation module and the temperature gradient compensation module.

[0050] The calibration conditions include complete shutdown of the glass substrate transfer platform 17 and absence of glass substrate, absence of glass substrate on the transfer platform during the production line board change interval, and timed calibration automatically triggered according to the preset duration of the production line.

[0051] During self-test, the coaxial laser sensor 2 emits a detection laser towards the calibration target 11. The spot image processor 3 acquires the grayscale data of the calibration target 11 and calculates the original defocus amount of the calibration target 11. Then, the self-test defocus amount is calculated sequentially through the material compensation module and the temperature gradient compensation module. The self-test defocus amount is compared with the preset reference defocus amount of the calibration target 11. If the deviation exceeds 0.1μm, a compensation command is automatically generated to drive the lens adjustment mechanism to complete the zero-position calibration until the deviation is ≤0.1μm.

[0052] Work process: The real-time focusing correction device for glass substrate re-inspection provided in this embodiment is installed on a G8.5 generation 2200mm×2500mm glass substrate re-inspection machine. It automatically loads a fused silica glass target for self-inspection. The material compensation module has pre-stored the optical parameters and temperature correction coefficient of 0.7mm thick glass.

[0053] During operation, the temperature sensor network monitors the temperature change of the mounting base 1 in real time, and the influence of ambient temperature on focusing accuracy is controlled within 0.05μm through a temperature gradient compensation algorithm.

[0054] When the net defocusing amount exceeds 0.3μm, the control unit 7 completes the calibration closed loop within 41ms. After 30 days of actual testing at Huaxing Optoelectronics Wuhan G8.5 generation line, the detection rate of 0.4μm micro-scratches increased from 78% to 96%, the daily maintenance calibration time was shortened from the traditional 2 hours to 72 seconds, the effective operating rate of the equipment increased by 17%, and the monthly loss of defective products was reduced by about 480,000 yuan.

[0055] Example 2 Based on the glass substrate re-inspection real-time focusing correction device provided in Embodiment 1, this embodiment provides a glass substrate re-inspection real-time focusing correction system, which is suitable for full-area focusing correction of large-size glass substrates of G8.5 generation and above (3370mm×2940mm). It includes a main control unit 13, multiple glass substrate re-inspection real-time focusing correction devices, and slave control units 14 that are configured one-to-one with the glass substrate re-inspection real-time focusing correction devices.

[0056] Multiple glass substrate re-inspection real-time focusing and correction devices are arrayed on the glass substrate along the detection area of ​​the glass substrate transfer platform 17. The distance between two adjacent glass substrate re-inspection real-time focusing and correction devices does not exceed 500mm. Preferably, the number of glass substrate re-inspection real-time focusing and correction devices does not exceed 64, which can achieve full coverage of the detection area of ​​a large-size glass substrate of 3370mm×2940mm.

[0057] refer to Figure 4 The glass substrate can be transported horizontally or vertically on the glass substrate transport platform 17, adapting to the bidirectional transport requirements of the production line. The yellow area in the figure is the non-inspection area at the edge of the glass substrate, and the white area in the middle is the effective inspection area of ​​the glass substrate. In the next re-inspection area, the effective inspection area and the non-inspection area are swapped to avoid the deployment of too many glass substrate re-inspection real-time focusing correction devices in the same inspection area, which would affect the glass substrate clamping and handling processes in the inspection area. By exchanging the inspection positions of the two re-inspection areas, full-coverage re-inspection can be achieved to meet the inspection requirements.

[0058] Combination Figure 1Each slave control unit 14 is installed on the mounting base 1 and communicates with the control unit 7 via the communication bus 15 to achieve high-speed data communication. Multiple slave control units 14 are all connected to the external master control unit 13 to construct a three-level control architecture of master control-slave control-correction device, so as to realize full-domain synchronous control of large-size glass substrate.

[0059] The main control unit 13 sends synchronous acquisition and drive commands to all slave control units 14 via the EtherCAT bus, with a synchronization delay of ≤1μs, ensuring that all correction devices complete data acquisition and command execution at the same time. The main control unit 13 receives local defocus data uploaded by each slave control unit 14 in real time, and constructs a focusing morphology map of the entire glass substrate through a built-in algorithm to accurately identify the focusing deviation distribution in the entire range. At the same time, the main control unit 13 coordinates the correction actions of adjacent correction devices according to the focusing morphology map to avoid correction interference and ensure that the focusing consistency difference within the 3370mm×2940mm detection range is ≤±0.35μm.

[0060] Upon receiving the instruction from the master control unit 13 forwarded by the slave control unit 14, the lens adjustment mechanism completes the precise correction of the focus height of its respective detection points and transmits the correction results back to the master control unit 13 in real time, realizing integrated control of "full-area monitoring - synchronous correction - result transmission".

[0061] refer to Figure 5 The real-time focusing correction system for glass substrate re-inspection provided in this embodiment has an extremely fast response speed, and can complete the entire focusing correction closed loop within 45ms, which is far superior to the existing technology. The focusing error fluctuation after correction is almost zero, and the focusing accuracy is stable at ≤0.3μm. It can be adapted to high-speed glass substrate transmission production lines with a speed of 4m / min or higher, and there is no response lag problem. It effectively solves the technical defects of poor focusing consistency and slow response in the inspection of large-size glass substrates in the existing system.

[0062] Work process: Forty-two sets of glass substrate re-inspection real-time focusing correction devices were deployed on the G10.5 generation 3370mm×2940mm glass substrate transmission platform 17 with a grid spacing of 500mm. The main control unit 13 achieved synchronous control through the EtherCAT bus.

[0063] Test results show that the standard deviation of the focusing deviation in the entire 3370mm×2940mm detection area is 0.17μm, and the maximum difference between the edge and the center is only ±0.35μm. For micro-defects at the 3μm level in the edge area, the missed detection rate is reduced from 17.5% in the existing technology to 2.3%. Under high-speed conditions with a substrate transmission speed of 4m / min, the system still maintains stable correction performance and there is no response lag.

[0064] Example 3 Based on the real-time focusing correction device for glass substrate re-inspection provided in Embodiment 1, this embodiment provides a real-time focusing correction method for glass substrate re-inspection, including the following steps: Obtain temperature field distribution data for mounting base 1; A detection laser is emitted toward a glass substrate, and the grayscale data of the light spot reflected from the glass substrate is acquired. The initial defocusing amount is calculated based on the grayscale data of the light spot. The net defocus amount is obtained by combining the original defocus amount and temperature field distribution data with a multi-dimensional compensation algorithm. The net defocus amount is compared with a preset threshold. When the net defocus amount exceeds the preset threshold, a piezoelectric drive voltage command is sent based on the net defocus amount. The height of the lens support 5 in its axial direction is adjusted according to the piezoelectric drive voltage command; Reacquire the net defocus amount and determine if it meets the correction value. If yes, end the process; otherwise, continue the correction.

[0065] Specifically, after the glass substrate re-inspection real-time focusing correction device is powered on and during operation, the self-test module identifies that the calibration conditions are met and performs self-tests in conjunction with the calibration target 11 through the temperature sensor network, focusing detection unit, material compensation module and temperature gradient compensation module until the deviation is ≤0.1μm; after the self-test calibration is completed, the device enters the standby state for normal testing.

[0066] During the correction process, if the protection module detects that the surface temperature of the glass substrate is ≥60℃, it will immediately trigger a high temperature warning and suspend detection. Data acquisition will be restarted after the production line adjusts the temperature control parameters and the glass substrate temperature returns to normal.

[0067] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the scope of the invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0068] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that can be understood by those skilled in the art. The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A real-time focusing correction device for glass substrate re-inspection, characterized in that, include: Mounting base (1) is provided on glass substrate transfer platform (17); a temperature sensor network is provided in the mounting base (1) to obtain temperature field distribution data of the mounting base (1); The focusing detection unit is used to emit a detection laser to the glass substrate and acquire the grayscale data of the light spot reflected by the glass substrate, and to preliminarily calculate the original defocusing amount based on the grayscale data of the light spot. Control unit (7) is used to obtain net defocus amount through multi-dimensional compensation algorithm based on original defocus amount and temperature field distribution data. When net defocus amount exceeds preset threshold, it sends piezoelectric drive voltage command based on net defocus amount. The lens adjustment mechanism is used to adjust the height of the lens carrier (5) in its axial direction according to the piezoelectric drive voltage command.

2. The real-time focusing correction device for glass substrate re-inspection according to claim 1, characterized in that, The focusing detection unit includes a coaxial laser sensor (2), a beam splitter (9), and a spot image processor (3). The coaxial laser sensor (2) is used to emit detection laser, and the coaxial laser sensor (2) is arranged on the periphery of the beam splitter (9) perpendicular to the axis of the lens mount (5); The beam splitter (9) is located between the lens carrier (5) and the glass substrate transmission platform (17). The beam splitter (9) is used to refract the detection laser to the detection point on the glass substrate and to guide the detection laser reflected by the glass substrate into the spot image processor (3). The light spot image processor (3) is located inside the lens mount (5) and coaxially arranged with the lens mount (5). The light spot image processor (3) is located above the main inspection objective (10). The light spot image processor (3) collects the mixed light spot grayscale data of the front and rear surfaces of the glass substrate through the built-in photosensitive array, quickly identifies and removes the reflection signal interference of the front and rear surfaces of the glass substrate through the grayscale threshold segmentation algorithm, and uses the phase difference to calculate the original defocus amount.

3. The real-time focusing correction device for glass substrate re-inspection according to claim 1, characterized in that, The control unit (7) includes: The material compensation module uses a Monte Carlo simulation model to correct the optical path of the original defocus amount based on the preset thickness and corresponding refractive index of the current glass substrate, and obtains the material-compensated defocus amount. The temperature gradient compensation module combines the temperature field distribution data to run the temperature gradient compensation algorithm, calculates the deformation of the mounting base (1) caused by thermal expansion, and compensates the material defocusing amount according to the deformation of the mounting base (1) to obtain the temperature compensation defocusing amount. The warp and vibration suppression module is used to fit the three-dimensional curved surface of the glass substrate through an edge warp compensation algorithm, and then filter the mechanical vibration noise generated during the transmission of the glass substrate through an adaptive Kalman filter algorithm to obtain the net defocus amount. The instruction generation module compares the obtained net defocus amount with a preset threshold. If the net defocus amount exceeds the preset threshold, it generates a corresponding piezoelectric drive voltage instruction based on the net defocus amount.

4. The real-time focusing correction device for glass substrate re-inspection according to claim 3, characterized in that, A calibration target (11) is installed on the mounting base (1) via a quick-release buckle, and the calibration target (11) is coaxially arranged with the main inspection objective (10); The control unit (7) also includes: The self-test module is used to obtain the status of the glass substrate transmission platform (17) in real time. If the glass substrate transmission platform (17) meets the calibration conditions, it will perform self-testing in conjunction with the calibration target (11) through the temperature sensor network, focusing detection unit, material compensation module and temperature gradient compensation module respectively.

5. The real-time focusing correction device for glass substrate re-inspection according to claim 1, characterized in that, The lens adjustment mechanism includes a piezoelectric ceramic actuator (4), a guide assembly (6), and a flexible hinge (12). The piezoelectric ceramic actuator (4) is connected to the lens carrier (5) via a flexible hinge (12), and the lens carrier (5) is slidably connected to the guide assembly (6) along its axial direction; The piezoelectric ceramic actuator (4) generates nanoscale stretching deformation based on the inverse piezoelectric effect according to the piezoelectric driving voltage command after D / A conversion and high voltage amplification, and drives the lens carrier (5) to move through the flexible hinge (12).

6. The real-time focusing correction device for glass substrate re-inspection according to claim 1, characterized in that, The calibration target (11) is selected as a fused silica glass target, and the coefficient of thermal expansion of the fused silica glass target is ≤0.33×10. -6 / ℃.

7. The real-time focusing correction device for glass substrate re-inspection according to claim 2, characterized in that, The coaxial laser sensor (2) emits a detection laser with a wavelength of 650nm±10nm and the power of the detection laser is 5mW±0.5mW; the beam splitter (9) has a transmittance of ≥90% for the 650nm wavelength laser.

8. The real-time focusing correction device for glass substrate re-inspection according to claim 5, characterized in that, The guide component (6) is a ball bearing guide sleeve, the linearity of the guide component (6) is ≤0.1μm / mm, the displacement resolution of the piezoelectric ceramic actuator (4) is ≤0.5nm, and the resonant frequency of the flexible hinge (12) is ≥2kHz.

9. A real-time focusing correction system for glass substrate re-inspection, characterized in that, It includes a main control unit (13), a glass substrate re-inspection real-time focusing correction device as described in any one of claims 1 to 8, and a slave control unit (14) that corresponds to the glass substrate re-inspection real-time focusing correction device. Multiple glass substrate re-inspection real-time focusing correction devices are arrayed along the detection area of ​​the glass substrate transmission platform (17). The slave control unit (14) is set on the mounting base (1) and communicates with the control unit (7). All of the slave control units (14) are communicated with the master control unit (13). The master control unit (13) sends a synchronization command to all slave control units (14), and the slave control units (14) upload the net defocus amount and correction result of the corresponding position of the glass substrate to the master control unit (13).

10. A real-time focusing correction method for re-inspection of glass substrates, characterized in that, The glass substrate re-inspection real-time focusing correction device according to any one of claims 1 to 8 includes the following steps: Obtain temperature field distribution data of the mounting base (1); A detection laser is emitted toward a glass substrate, and the grayscale data of the light spot reflected from the glass substrate is acquired. The initial defocusing amount is calculated based on the grayscale data of the light spot. The net defocus amount is obtained by combining the original defocus amount and temperature field distribution data with a multi-dimensional compensation algorithm. The net defocus amount is compared with a preset threshold. When the net defocus amount exceeds the preset threshold, a piezoelectric drive voltage command is sent based on the net defocus amount. The height of the lens carrier (5) in its axial direction is adjusted according to the piezoelectric drive voltage command; Reacquire the net defocus amount and determine if it meets the correction value. If yes, end the process; otherwise, continue the correction.

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