Ceramic core interdigital electrode optical calibration method and system

Abstract

The invention discloses a ceramic core interdigital electrode optical calibration method and system, and relates to the technical field of ceramic core interdigital electrode manufacturing, the system comprises an optical / electron microscope measurement unit, a precision motion platform, an image acquisition and processing module, a data processing module, a laser engraving unit, a data storage and interaction module and a photoetching standard component; the resolution ratio of the optical / electron microscope measuring unit is greater than or equal to 0.1 mu m, and the optical / electron microscope measuring unit is used for acquiring a sub-pixel electrode image; the positioning precision of the precise motion platform is + / -1 [mu] m to realize uniform sampling; the data processing module executes three-level abnormal value processing and a weighted truncation average algorithm to ensure the calibration precision; and the laser engraving unit and the data storage module realize calibration value physical retention and full-link data tracing.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ceramic core interdigital electrode manufacturing, in particular to a ceramic core interdigital electrode optical calibration method and system. BACKGROUND

[0002] As the core component of gas sensors, humidity sensors and other devices, the precision of the interdigital electrode pitch of the ceramic core interdigital electrode directly affects the performance parameters of the sensor. In order to ensure the quality of the sensor, the ceramic core interdigital electrode needs to be calibrated to determine its actual interdigital pitch. The current calibration of automobile particulate matter exhaust sensors (such as ceramic core sensors based on interdigital electrodes) generally uses a soot generator calibration method: using flammable gases such as ethylene and methane as fuel, precise control of the combustion process generates carbon particles with a particle size of about 100 nm; place the sensor ceramic core in the soot generating environment, after the carbon particles are adsorbed between the interdigital electrodes of the ceramic core to form a path, detect the electrode current corresponding to different particle concentrations, establish the "current-concentration" correspondence, and complete the calibration. This method is a traditional sensor performance calibration method in the industry and is widely used in the performance calibration link before mass production of particulate matter sensors.

[0003] However, the existing soot generator calibration method has the following defects:

[0004] 1. Extremely low batch production efficiency: single ceramic core calibration needs to go through the whole process of "soot generation-adsorption-current detection-cleaning reset", and the time consumption of single calibration is ≥30 minutes. Due to the limitation of soot concentration stability, it is difficult to realize the parallel calibration of multiple ceramic cores, and it cannot adapt to the mass production demand of thousands of ceramic cores per day.

[0005] 2. High safety risk: the calibration process relies on flammable gases such as ethylene and methane, and there is a risk of leakage in the gas storage and transportation link. If the combustion process is not properly controlled, it may cause deflagration. At the same time, the soot dust generated by combustion is easy to adhere to the inner wall of the equipment, and long-term accumulation may cause pipeline blockage or equipment failure, increasing the safety hidden danger in the maintenance process.

[0006] 3. Strict equipment consistency requirement and high cost: the uniformity of the particle size and concentration of soot directly determines the calibration accuracy, which requires strict control of the combustion parameters through high-precision flow valves, temperature control modules, pressure sensors and other components, resulting in high initial investment cost of the equipment. During the operation of the equipment, component wear (such as flow valve aging) may easily lead to drift of soot parameters, requiring frequent calibration of the equipment, further increasing the operation and maintenance cost.

[0007] 4. Poor traceability of calibration results: the traditional method only records the final "current-concentration" corresponding value of the ceramic core, and does not store the key parameters (such as soot concentration fluctuation and electrode initial state) in the calibration process. If the performance of the sensor is abnormal later, it is difficult to trace the root cause of the problem (is it a calibration deviation or a defect of the ceramic core itself).

[0008] Therefore, there is an urgent need for an efficient, high-precision, safe, and traceable ceramic core interdigital electrode calibration method and system to solve the problems of the prior art. SUMMARY

[0009] The present application aims to solve the above technical problems and provides a ceramic core interdigital electrode optical calibration method and system.

[0010] To solve the above technical problems, the technical solution provided by the present application is as follows:

[0011] A ceramic core interdigital electrode optical calibration method, comprising the following steps:

[0012] Step 1: Ceramic core positioning and image acquisition:

[0013] Scan the unique two-dimensional code of the ceramic core, and the system calls the calibration parameters corresponding to the ceramic core; the precision motion platform automatically grabs the ceramic core and positions it under the optical / electron microscope measurement unit, realizes automatic focusing based on the edge contrast maximization algorithm; according to the preset sampling path, the precision motion platform drives the ceramic core to move, and the optical / electron microscope measurement unit acquires images of multiple adjacent spacings corresponding to multiple pairs of interdigital electrodes of the ceramic core point by point, acquires images of multiple sampling points for each spacing, and transmits the images to the image acquisition and processing module in real time;

[0014] Step 2: Image preprocessing and edge positioning:

[0015] The image acquisition and processing module performs Gaussian filtering with σ=1.5 on each sampling point image to eliminate electronic noise; highlights the gray difference between the electrodes and the ceramic substrate through the Laplacian operator; uses the OTSU algorithm to automatically determine the gray threshold, converts the image into a binary image with white electrodes and black substrate; calculates the X1 coordinate of the right edge of the left electrode and the X2 coordinate of the left edge of the right electrode based on the Zernike moment method, and obtains the single sampling point spacing s=|X2-X1|, unit: μm;

[0016] Step 3: Outlier processing and robust spacing calculation:

[0017] Single-spacing outlier processing: for multiple sampling points s values collected for each spacing, first eliminate severe outliers with s≤30 μm or s≥60 μm; sort the remaining s values, calculate Q1, i.e., the 25th percentile, Q3, i.e., the 75th percentile, and IQR=Q3-Q1, eliminate moderate outliers with <Q1-1.2×IQR or >Q3+1.2×IQR; if the number of valid sampling points is <10, mark the spacing as invalid; if the number of valid sampling points is ≥10, calculate the weighted value according to the weight of the middle 3 segments of sampling points 1.2 and the weight of the two end segments of sampling points 0.8, and then remove the highest 5% and lowest 5% values in the weighted value to obtain the single-spacing representative value Si;

[0018] All-ceramic core calibration value calculation: the number of effective representative values of a plurality of adjacent intervals is counted, if the effective number <20, the ceramic core is determined to be unqualified; if the effective number ≥20, the highest 2 and the lowest 2 values in the effective representative values are removed, the remaining values are averaged to obtain the final calibration value Snet, and the last one decimal place is retained; at the same time, the standard deviation σ and the abnormal point ratio of the effective representative values are calculated, and the abnormal point ratio is the ratio of the number of invalid intervals to the number of a plurality of adjacent interval values;

[0019] Step 4: calibration result output and data traceability:

[0020] The laser engraving unit engraves the final calibration value Snet on the non-electrode area of the ceramic core; the data storage and interaction module uploads the ceramic core two-dimensional code, the final calibration value Snet, the standard deviation σ, the abnormal point ratio and the original image path to the MES system; the qualified ceramic cores flow into the next production link, and the unqualified ceramic cores are labeled and returned to the special unqualified product warehouse.

[0021] Preferably, before step 1, a preliminary calibration process is further included, which is performed before daily production, and the time consumption is ≤15 minutes;

[0022] The specific steps are: fixing the photoetching standard part on the precise motion platform, collecting 3 groups of images according to the sampling parameters of collecting a plurality of sampling points per interval and uniformly dividing 5 sections; calculating the interval of the photoetching standard part through the image acquisition and processing module, if the deviation of the calculated measurement value and the standard interval of the photoetching standard part is >0.5μm, adjusting the focal length, exposure time of the optical / electron microscope measurement unit or the positioning compensation value of the precise motion platform, until the deviation is ≤0.5μm, and the system calibration is completed.

[0023] Preferably, after step 4, a sampling verification process is further included,

[0024] The specific steps are: every week, 1%-3% of the ceramic cores are randomly taken from the qualified ceramic cores, and the calibration is performed by using a soot generator; comparing the final calibration value Snet of the ceramic core with the equivalent interval value calibrated by the soot generator, if the deviation is ≤1μm, the optical calibration system is determined to be normal; if the deviation is >1μm, the optical / electron microscope measurement unit is recalibrated, and 10% of the ceramic cores produced in the last 3 days are additionally sampled.

[0025] Preferably, the preset calibration parameters in step 1 include a plurality of adjacent intervals corresponding to a plurality of pairs of interdigital electrodes of the sampling object, each interval has an effective sampling length of 7.5 mm, and each interval has a process deformation zone of 0.2 mm at both ends of the electrode; the single-interval sampling strategy is to divide the length direction into 5 segments, and sample 3 points (left, middle and right) in each segment, so as to obtain 15 sampling points per interval; the abnormal value judgment threshold is set based on the process tolerance 43.8-53.1 μm, the serious abnormality is s≤30 μm or s≥60 μm, and the moderate abnormality is 30 μm

[0026] Preferably, the standard deviation σ calculated in step 3 is used to quantify the uniformity of the electrode interval, and the proportion of abnormal points is used to reflect the overall quality of the ceramic core. The final calibration value Snet, the standard deviation σ and the proportion of abnormal points are used as the quality indicators of the ceramic core.

[0027] Preferably, after the unqualified ceramic core is put into the special unqualified product warehouse in step 4, the unqualified reason is also recorded, the unqualified reason includes electrode short circuit, edge deformation and insufficient effective interval number, and the unqualified reason is associated with the two-dimensional code of the ceramic core and stored in the MES system.

[0028] Preferably, the plurality of images collected by the optical / electron microscope measurement unit in step 1 are all transmitted to the data storage and interaction module in real time for backup storage, which is used for subsequent traceability and troubleshooting.

[0029] The application also provides a ceramic core interdigital electrode optical calibration system, comprising:

[0030] An optical / electron microscope measurement unit, the resolution of the optical / electron microscope measurement unit is ≥0.1 μm, the magnification is 500-1000 times, the field of view is ≥100 μm×100 μm, the gray scale image collection with 12 bit pixel depth is supported, and the optical / electron microscope measurement unit is used for capturing the edge of the ceramic core interdigital electrode and obtaining sub-pixel level image details;

[0031] A precision motion platform, the positioning accuracy of the precision motion platform is ±1 μm, the repeat positioning accuracy is ±0.5 μm, the stroke is ≥60 mm×5 mm, the linear scanning and point positioning are supported, and the precision motion platform is used for driving the ceramic core to move along a preset path to realize uniform sampling of the whole length of the electrode;

[0032] An image acquisition and processing module, the frame rate of the image acquisition and processing module is ≥15 fps, the Gaussian filter, OTSU binaryzation and Zernike moment edge detection algorithm are integrated, and the image acquisition and processing module is used for real-time processing of image noise and accurate positioning of electrode edge coordinates;

[0033] A data processing module, the data processing module is used for executing three-level abnormal value processing and weighted truncated average algorithm, and calculating the calibration value of the ceramic core interdigital electrode;

[0034] A laser engraving unit with an engraving accuracy of ±0.1 mm, an engraving depth of ≤0.1 mm, and support for character and number output, for engraving calibration values on the non-electrode area of the ceramic core;

[0035] A data storage and interaction module integrated with an MES system interface, supporting two-dimensional code scanning, for storing the original image, calibration parameters and quality indicators of the ceramic core, and realizing the association of ceramic core data and the production system.

[0036] Compared with the prior art, the present application has the following beneficial effects:

[0037] 1. Efficiency is significantly improved: single ceramic core calibration time is ≤2 minutes, efficiency is improved by more than 15 times; double-station design is adopted, and daily calibration capacity is ≥1000, meeting the batch production demand;

[0038] 2. High precision: calibration accuracy is ±0.3 μm, which is 5 times higher than that of traditional methods; coefficient of variation is ≤2%, and consistency is significantly improved;

[0039] 3. Good safety: no flammable gas is used, and safety hazards such as burning and explosion are completely eliminated;

[0040] 4. Strong traceability: through the association of original image, calibration parameters, quality indicators and other whole-process data through two-dimensional code, the root cause of quality problems can be traced;

[0041] 5. Low cost: reduces equipment calibration frequency and consumable consumption, and reduces operation and maintenance cost.

[0042] The present application breaks through the technical limitations of the traditional carbon smoke generator calibration method, realizes efficient, high-precision and safe calibration of the ceramic core interdigital electrode through optical direct measurement combined with an automatic system, and has important industrial application value.

[0043] The above summary is only for the purpose of the description and is not intended to limit in any way. In addition to the illustrative aspects, embodiments and features described above, further aspects, embodiments and features will be readily apparent to those skilled in the art by reference to the drawings and the following detailed description. BRIEF DESCRIPTION OF DRAWINGS

[0044] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0045] Figure 1 is a flowchart of the present application. Detailed Implementation

[0046] Specific embodiments of the invention will now be described in detail. Although the invention is described in conjunction with these specific embodiments, it should be understood that the invention is not intended to be limited to these specific embodiments. Rather, these embodiments are intended to cover alternative, modified, or equivalent embodiments that may be included within the spirit and scope of the invention as defined by the claims. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the invention. The invention may be practiced without some or all of these specific details. In other instances, well-known processes have not been described in detail so as not to unnecessarily obscure the invention.

[0047] When used in conjunction with the terms "comprising," "method comprising," or similar language in this specification and appended claims, the singular forms "a," "some," and "the" include plural references unless the context clearly indicates otherwise. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0048] The present invention will now be described in further detail with reference to the full text.

[0049] Combined with appendix Figure 1 A method for optical calibration of ceramic core interdigitated electrodes includes the following steps:

[0050] Step 1: Ceramic core positioning and image acquisition:

[0051] Scanning the unique QR code on the ceramic core triggers the system to retrieve the corresponding calibration parameters. A precision motion platform automatically grabs the ceramic core and positions it below the optical / electron microscope measurement unit, achieving autofocus based on an edge contrast maximization algorithm. Following a preset sampling path, the precision motion platform moves the ceramic core, and the optical / electron microscope measurement unit sequentially acquires images of 23 adjacent intervals corresponding to the 12 pairs of interdigitated electrodes (≥1 pair can be operated, taking 12 pairs as an example). Images of 15 sampling points are acquired at each interval (≥1 pair can be operated, taking 15 adjacent intervals as an example), resulting in a total of 345 images. These images are transmitted in real-time to the image acquisition and processing module.

[0052] Step 2, Image Preprocessing and Edge Localization:

[0053] The image acquisition and processing module performs Gaussian filtering with sigma = 1.5 on each sampling point image to eliminate electronic noise; highlights the gray difference between the electrode and the ceramic substrate through the Laplace operator; converts the image into a binary image with the electrode in white and the substrate in black by automatically determining the gray threshold value using the OTSU algorithm; calculates the X1 coordinate of the right edge of the left electrode and the X2 coordinate of the left edge of the right electrode based on the Zernike moment method, and obtains the single sampling point spacing s = |X2-X1|, unit: μm;

[0054] Step 3, outlier processing and robust spacing calculation:

[0055] Single spacing outlier processing: for the s value of 15 sampling points in a single spacing, first eliminate the serious outliers with s≤30μm or s≥60μm; sort the remaining s values, calculate Q1, i.e. the 25th percentile, Q3, i.e. the 75th percentile, and IQR = Q3-Q1, and eliminate the moderate outliers with <Q1-1.2×IQR or >Q3+1.2×IQR; if the number of valid sampling points is <10, mark the spacing as invalid; if the number of valid sampling points is ≥10, calculate the weighted value according to the weight of 1.2 for the middle 3 segments of sampling points and the weight of 0.8 for the two end segments of sampling points, and then remove the highest 5% and the lowest 5% values in the weighted value to obtain the single spacing representative value S i ;

[0056] All-ceramic core calibration value calculation: count the number of valid representative values of 23 spacings, if the number of valid values is <20, determine that the ceramic core is unqualified; if the number of valid values is ≥20, remove the highest 2 and the lowest 2 values in the valid representative values, and take the average of the remaining values to obtain the final calibration value S net , retaining 1 decimal place; at the same time, calculate the standard deviation σ and the abnormal point ratio of the valid representative values, and the abnormal point ratio is the ratio of the number of invalid spacings to 23;

[0057] Step 4, calibration result output and data traceability:

[0058] The laser engraving unit engraves the final calibration value S net on the non-electrode area of the ceramic core; the data storage and interaction module uploads the ceramic core two-dimensional code, the final calibration value S net , the standard deviation σ, the abnormal point ratio and the original image path to the MES system; the qualified ceramic cores flow into the next production link, and the unqualified ceramic cores are labeled and returned to the special unqualified product warehouse.

[0059] Before step 1, there is also a pre-calibration process, which is performed before daily production, and the time consumption is ≤15 minutes;

[0060] The specific steps are as follows: the photolithography standard part is fixed on a precise motion platform, 3 groups of images are collected according to 15 sampling points per interval, and the interval is evenly divided into 5 segments; the interval of the photolithography standard part is calculated through an image acquisition and processing module, if the deviation between the calculated measurement value and the standard interval of the photolithography standard part is greater than 0.5 microns, the focal length, exposure time or positioning compensation value of the optical / electron microscope measurement unit or the precise motion platform is adjusted until the deviation is less than or equal to 0.5 microns, and the system calibration is completed.

[0061] The method further comprises a sampling verification process after step 4,

[0062] The specific steps are as follows: 1%-3% of the qualified ceramic cores are randomly selected from the qualified ceramic cores every week, and the carbon smoke generator is used for calibration; the final calibration value S of the ceramic core is compared with the equivalent interval value calibrated by the carbon smoke generator, if the deviation is less than or equal to 1 micron, it is determined that the optical calibration system is normal, if the deviation is greater than 1 micron, the optical / electron microscope measurement unit is recalibrated, and 10% of the ceramic cores produced in the last 3 days are additionally sampled. net The final calibration value S of the ceramic core is compared with the equivalent interval value calibrated by the carbon smoke generator, if the deviation is less than or equal to 1 micron, it is determined that the optical calibration system is normal, if the deviation is greater than 1 micron, the optical / electron microscope measurement unit is recalibrated, and 10% of the ceramic cores produced in the last 3 days are additionally sampled.

[0063] The preset calibration parameters in step 1 include 23 adjacent intervals corresponding to 12 pairs of interdigital electrodes as the sampling object, the effective sampling length of each interval is 7.5 mm, and the process deformation area of 0.2 mm at both ends of the electrode is removed; the single-interval sampling strategy is to evenly divide each interval into 5 segments along the length direction, and 3 points are sampled in each segment, that is, 15 sampling points per interval; the abnormal value judgment threshold is set based on the process tolerance 43.8-53.1 microns, the serious abnormality is s≤30 microns or s≥60 microns, and the moderate abnormality is 30 microns

[0064] The standard deviation σ calculated in step 3 is used to quantify the uniformity of the electrode interval, the abnormal point ratio is used to reflect the overall quality of the ceramic core, and the final calibration value S net , the standard deviation σ and the abnormal point ratio are used as the quality indicators of the ceramic core.

[0065] The unqualified ceramic cores in step 4 are put into a special unqualified product warehouse, and the unqualified reasons are also recorded, the unqualified reasons include electrode short circuit, edge deformation, insufficient effective interval number, and the unqualified reasons are associated with the two-dimensional code of the ceramic core and stored in the MES system.

[0066] The 345 images collected by the optical / electron microscope measurement unit in step 1 are all transmitted to the data storage and interaction module for backup storage, which is used for subsequent traceability and fault troubleshooting.

[0067] The results of the method of the present application compared with the prior art are shown in the following table 1:

[0068] Table 1

[0069]

[0070]

[0071] The application also provides a ceramic core interdigital electrode optical calibration system, comprising:

[0072] An optical / electron microscope measurement unit, which has a resolution of ≥0.1 μm, a magnification of 500-1000 times, a field of view of ≥100 μm×100 μm, supports 12-bit pixel depth grayscale image acquisition, and is used for capturing the edge of the ceramic core interdigital electrode and obtaining sub-pixel level image details;

[0073] A precision motion platform, which has a positioning accuracy of ±1 μm, a repeat positioning accuracy of ±0.5 μm, a stroke of ≥60 mm×5 mm, supports linear scanning and point positioning, and is used for driving the ceramic core to move along a preset path to realize uniform sampling of the full length of the electrode;

[0074] An image acquisition and processing module, which has a frame rate of ≥15 fps, integrates Gaussian filtering, OTSU binarization and Zernike moment edge detection algorithms, and is used for real-time processing of image noise and accurate positioning of electrode edge coordinates;

[0075] A data processing module, which is used for performing three-level outlier processing and weighted truncated average algorithm to calculate the calibration value of the ceramic core interdigital electrode;

[0076] A laser engraving unit, which has an engraving accuracy of ±0.1 mm, an engraving depth of ≤0.1 mm, supports character and number output, and is used for engraving the calibration value on the non-electrode area of the ceramic core;

[0077] A data storage and interaction module, which integrates an MES system interface, supports two-dimensional code scanning, is used for storing the original image, calibration parameters and quality indicators of the ceramic core, and realizes the association of ceramic core data and the production system.

[0078] The hardware system is composed as shown in Table 2 below.

[0079] Table 2

[0080]

[0081] The application replaces the traditional carbon smoke generator with an "optical / electron microscope measurement unit + precision motion platform + laser engraving unit", realizes non-contact calibration without flammable gas, and solves the problems of high safety risk and low efficiency of the traditional method.

[0082] The present application is aimed at a three-level abnormal value processing algorithm for interdigital electrode spacing measurement: ① severe abnormal values (s≤30μm or s≥60μm) are first removed; ② moderate abnormal values are removed by a modified quartile method (1.2*IQR); ③ the remaining effective points are calculated for weighted values according to "regional weight distribution" and the extreme values are truncated, effectively resisting local defect interference such as electrode short circuit and edge deformation, and improving the accuracy of the calibration value.

[0083] The present application is suitable for automatic calibration of the whole process of mass production: integrating the functions of "two-dimensional code recognition-automatic positioning and focusing-image acquisition and processing-calibration value calculation-laser engraving-MES data uploading", achieving a calibration time of less than 2 minutes for a single ceramic core, and the data can be traced through the whole link, solving the problems of low efficiency and poor traceability of traditional methods.

[0084] The present application is based on a multi-dimensional quality judgment standard of "average spacing + standard deviation + abnormal point proportion": not only the calibration value is output, but also the electrode spacing uniformity is quantified by the standard deviation and the overall quality of the ceramic core is reflected by the proportion of abnormal points, avoiding the "qualified but poor performance" products caused by traditional "single value calibration" from flowing into the downstream, and improving the overall reliability of the sensor.

[0085] The present application adopts a combined verification mode of "optical calibration + carbon smoke generator test": during mass production, optical rapid calibration is adopted, and carbon smoke generator test is used for calibration on a regular basis, taking into account the batch efficiency and calibration accuracy, and solving the efficiency bottleneck of traditional methods which rely on carbon smoke generator.

[0086] Example one:

[0087] I. System configuration

[0088] The "single optical measurement unit + single precision motion platform" architecture is adopted, and the core module parameters strictly follow the limitations of the claims:

[0089] Optical / electron microscope measurement unit: resolution 0.1μm, magnification 800 times, field of view 100μm×100μm, 12bit pixel depth gray collection;

[0090] Precise motion platform: positioning accuracy ±1μm, repeat positioning accuracy ±0.5μm, stroke 60mm×5mm;

[0091] Image acquisition and processing module: frame rate 15fps, integrated Gaussian filter (σ=1.5), OTSU binaryzation, Zernike moment edge detection algorithm;

[0092] Laser engraving unit: engraving accuracy ±0.1mm, engraving depth 0.08mm;

[0093] Photoetching standard part: interdigital spacing 48μm±0.05μm, line width accuracy ±0.05μm.

[0094] II. Calibration process is as follows:

[0095] 1. Pre-calibration (before daily production, time-consuming 12 minutes).

[0096] Fix the lithography standard on the motion platform, collect 3 groups of images according to "15 sampling points per pitch, evenly divided into 5 sections"; the image processing module calculates the standard pitch, the first measurement value is 48.03 μm, the deviation is 0.03 μm≤0.5 μm, no adjustment is needed, and the calibration is completed.

[0097] 2. Ceramic core positioning and image acquisition (40 seconds).

[0098] Scan the unique two-dimensional code (number CX240601-001) of the ceramic core, and the system calls the calibration parameters: the sampling object is 23 adjacent pitches corresponding to 12 pairs of interdigital electrodes, the effective sampling length of each pitch is 7.5 mm (excluding the process deformation area of 0.2 mm at both ends), and each pitch is divided into 5 sections along the length direction, and 3 points (left, middle and right) are sampled in each section (a total of 15 sampling points / pitch).

[0099] The motion platform grabs the ceramic core and positions it under the optical unit, and automatically focuses through "maximizing edge contrast"; moves according to the preset path, and the optical unit collects 345 images of 23 pitches point by point, and transmits them to the processing module in real time.

[0100] 3. Image preprocessing and edge positioning (35 seconds).

[0101] Perform Gaussian filtering with σ = 1.5 on each image to eliminate electronic noise.

[0102] Laplacian operator highlights the gray difference between the electrode (gray value 2780) and the substrate (gray value 1150);

[0103] OTSU algorithm automatically determines the gray threshold value 1920, and converts the image to "electrode white-substrate black" binary image;

[0104] Zernike moment method calculates the right edge of the left electrode X1 = 125.32 μm, the left edge of the right electrode X2 = 173.45 μm, and the single sampling point pitch s = |173.45-125.32| = 48.13 μm.

[0105] 4. Abnormal value processing and robust pitch calculation (25 seconds).

[0106] Single interval processing: the 8th interval 15 sampling points s value is 47.92 μm, 48.05 μm, 47.88 μm, 48.13 μm, 47.98 μm, 48.02 μm, 47.95 μm, 48.08 μm, 48.10 μm, 47.85 μm, 48.01 μm, 47.96 μm, 48.03 μm, 47.90 μm, 48.07 μm; no s≤30 μm or s≥60 μm serious outliers; after sorting Q1=47.90 μm, Q3=48.08 μm, IQR=0.18 μm, eliminate <47.90-1.2×0.18=47.68 μm or >48.08+1.2×0.18=48.30 μm value (no moderate outliers); according to "middle 3 section weight 1.2, both ends 2 section weight 0.8" to calculate the weighted value, remove the highest 5% (48.13 μm) and the lowest 5% (47.85 μm), single interval representative value S i = 48.00 μm;

[0107] All ceramic core calculation: 23 interval effective representative value 22 (≥20), remove the highest 2 (48.25 μm, 48.18 μm) and the lowest 2 (47.72 μm, 47.68 μm), the remaining 18 values are averaged, the final calibration value S net = 48.0 μm (retain 1 decimal place); standard deviation σ = 0.12 μm, abnormal point ratio = (23-22) / 23 ≈ 4.3%.

[0108] 5. Calibration result output and data traceability (20 seconds).

[0109] The laser engraving unit engraves "48.0 μm" in the non-electrode area of the ceramic core;

[0110] The data storage module uploads the two-dimensional code, S net = 48.0 μm, σ = 0.12 μm, abnormal point ratio 4.3%, original image path to MES system;

[0111] The ceramic core is determined to be qualified and flows into the next link.

[0112] III. Application effect.

[0113] Single ceramic core calibration time is 1.8 minutes, daily calibration 520; continuous operation for 15 days, the variation coefficient of calibration result is 1.6%≤2%, the unqualified product rate is 2.1%; through the MES system, 1 case of sensor current abnormality is located as "assembly deviation", and the traceability is verified.

[0114] Example two:

[0115] I. System configuration

[0116] Adopting "double optical measurement unit + double precision motion platform" parallel architecture, parameter adaptation to national six standard:

[0117] Optical / electron microscope measurement unit (2 sets): resolution 0.08 μm, magnification 1000 times, field of view 90 μm x 90 μm, 12 bit pixel depth;

[0118] Precision motion platform (2 sets): positioning accuracy ±0.8 μm, repeat positioning accuracy ±0.4 μm, stroke 70 mm x 6 mm;

[0119] Image acquisition and processing module: frame rate 20 fps, algorithm parameters same as example one;

[0120] Laser engraving unit (2 sets): engraving accuracy ±0.08 mm, engraving depth 0.06 mm;

[0121] Photoetching standard part: interdigital spacing 48 μm ±0.03 μm, line width accuracy ±0.03 μm.

[0122] II. The whole process of calibration is as follows:

[0123] 1. Early calibration (before daily production, time-consuming 14 minutes).

[0124] 2 sets of optical unit synchronous calibration: photoetching standard part measurement value is 48.02 μm, 48.01 μm, deviation is less than or equal to 0.5 μm, calibration is completed.

[0125] 2. Double station parallel calibration, positioning and acquisition (35 seconds): after scanning two-dimensional code, national six special parameters (same as example 1) are called, 345 images are collected;

[0126] Pretreatment and positioning (30 seconds): Gaussian filter σ=1.5, OTSU threshold 1910, it is calculated that a sampling point x1=98.76 μm, x2=146.83 μm, s=48.07 μm;

[0127] Abnormal value processing (22 seconds): 23 interval effective representative values, remove the highest 2 (48.15

[0128] μm, 48.12 μm) and the lowest 2 (47.92 μm, 47.90 μm), S net =48.0 μm, σ=0.09

[0129] μm, abnormal point ratio 0%;

[0130] Result output (18 seconds): engraving "48.0 μm" and uploading MES.

[0131] 3. Sampling verification.

[0132] Take out 2% (24) from qualified ceramic cores, and use carbon smoke generator to calibrate;

[0133] Contrast optical calibration value S net = 48.0 μm and carbon smoke backstepping equivalent interval value = 48.0 μm, deviation 0 μm≤1 μm, judge system normal;

[0134] No deviation exceeds the standard, no need to add sampling.

[0135] Three, application effect.

[0136] Double-station parallel calibration single particle consumes 1.5 minutes, and 1280 particles are calibrated per day; the calibration accuracy is ±0.2 μm, which meets the national six standards; the sampling deviation is all less than or equal to 0.8 μm, the coefficient of variation is 1.2%, the unqualified product rate is 1.5%, and the downstream assembly rework rate is reduced to 0.3%.

[0137] The above describes the present application and its embodiments, which is not restrictive, and the shown in the full text is only one of the embodiments of the present application, and the actual structure is not limited thereto. In general, if a person skilled in the art is inspired, without departing from the purpose of the present application, without creative design, similar structure and embodiments of the technical solution can be designed, which should belong to the protection scope of the present application.

Claims

1. A method of optical calibration of ceramic core interdigitated electrodes, characterized by, Comprising the following steps: Step 1: Ceramic core positioning and image acquisition: Scanning the unique two-dimensional code of the ceramic core, the system calls the corresponding calibration parameters of the ceramic core; the precision motion platform automatically grabs the ceramic core and positions it under the optical / electron microscope measurement unit, and realizes automatic focusing based on the edge contrast maximization algorithm; According to the preset sampling path, the precision motion platform drives the ceramic core to move, and the optical / electron microscope measurement unit collects images of multiple adjacent spacings corresponding to multiple pairs of interdigital electrodes of the ceramic core point by point, collects multiple sampling point images for each spacing, and the images are transmitted to the image acquisition and processing module in real time; Step 2: Image preprocessing and edge positioning: The image acquisition and processing module performs Gaussian filtering with σ=1.5 on each sampling point image to eliminate electronic noise; highlights the gray difference between the electrodes and the ceramic substrate through the Laplacian operator; uses the OTSU algorithm to automatically determine the gray threshold, converts the image into a binary image with white electrodes and black substrate; calculates the X1 coordinate of the right edge of the left electrode and the X2 coordinate of the left edge of the right electrode based on the Zernike moment method, and obtains the single sampling point spacing s=|X2-X1|, unit: μm; Step 3: Abnormal value processing and robust spacing calculation: Single interval outlier processing: collect multiple sampling points of s value for each interval, first eliminate s≤30μm or s≥60μm serious outliers; sort the remaining s values, calculate Q1, i.e. 25th percentile, Q3, i.e. 75th percentile, and IQR=Q3-Q1, eliminate moderate outliers <Q1-1.2×IQR or >Q3+1.2×IQR; if the remaining valid sampling points are <10, mark the interval as invalid; if the valid sampling points are ≥10, calculate the weighted value according to the middle 3 segment sampling points weight 1.2 and the two end 2 segment sampling points weight 0.8, then remove the highest 5% and lowest 5% values in the weighted value to obtain the single interval representative value S i ; All-ceramic core calibration value calculation: the number of effective representative values of multiple adjacent intervals is counted, if the effective number <20, it is determined that the ceramic core is unqualified; if the effective number ≥20, the highest 2 and the lowest 2 values in the effective representative values are removed, the remaining values are averaged to obtain the final calibration value S net , retaining 1 decimal place; at the same time, the standard deviation σ and the abnormal point ratio of the effective representative values are calculated, and the abnormal point ratio is the ratio of the number of invalid intervals to the number of multiple adjacent interval values; Step 4: Calibration result output and data traceability: The laser engraving unit will engrave the final calibration value S net Engraving on the non-electrode area of the ceramic core; the data storage and interaction module uploads the ceramic core two-dimensional code, final calibration value S net , standard deviation σ, abnormal point proportion and original image path to the MES system; qualified ceramic cores flow into the next production link, and unqualified ceramic cores are labeled and returned to the special unqualified product warehouse.

2. The method of claim 1, wherein: Before step 1, there is also a pre-calibration process, which is performed before daily production and takes ≤15 minutes; The specific steps are: fix the photolithography standard part on the precision motion platform, collect 3 groups of images according to the sampling parameters of collecting multiple sampling points for each spacing and evenly dividing 5 segments; calculate the spacing of the photolithography standard part through the image acquisition and processing module, if the deviation between the calculated measurement value and the standard spacing of the photolithography standard part is >0.5 μm, adjust the focal length, exposure time of the optical / electron microscope measurement unit or the positioning compensation value of the precision motion platform until the deviation is ≤0.5 μm, complete the system calibration.

3. The method of claim 1, wherein: After step 4, there is also a sampling verification process, The specific steps are: every week, 1%-3% of the qualified ceramic cores, but not less than 10, are randomly selected, and a carbon smoke generator is used for calibration; the final calibration value S of the ceramic core is compared net The equivalent interval value calibrated by the carbon smoke generator is compared, if the deviation is less than or equal to 1 μm, it is determined that the optical calibration system is normal; if the deviation is greater than 1 μm, the optical / electron microscope measurement unit is recalibrated, and 10% of the ceramic cores produced in the last 3 days are additionally sampled.

4. The method of claim 1, wherein: The preset calibration parameters in step 1 include the sampling object as multiple pairs of interdigital electrodes corresponding to multiple adjacent spacings, and the effective sampling length for each spacing is 7.5 mm, excluding the process deformation area of 0.2 mm at both ends of the electrode; The single spacing sampling strategy is to evenly divide 5 segments along the length direction, and collect 3 points in each segment, a total of 15 sampling points per spacing; the abnormal value judgment threshold is set based on the process tolerance 43.8-53.1 μm, the serious abnormality is s≤30 μm or s≥60 μm, and the moderate abnormality is 30 μm 5. The method of claim 1, wherein: The standard deviation σ calculated in step 3 is used to quantify the uniformity of the electrode spacing, and the proportion of abnormal points is used to reflect the overall quality of the ceramic core. The final calibration value S net The standard deviation σ and the proportion of abnormal points are used as quality indicators for the ceramic core.

6. The method of claim 1, wherein: In step 4, the unqualified ceramic core is put into a special unqualified product warehouse, and the unqualified reason is also recorded, which includes electrode short circuit, edge deformation, and insufficient number of effective spacings, and the unqualified reason is associated with the two-dimensional code of the ceramic core and stored in the MES system.

7. The method of claim 1, wherein: In step 1, the multiple images collected by the optical / electron microscope measurement unit are all transmitted to the data storage and interaction module for backup storage, which is used for subsequent traceability and troubleshooting.

8. A ceramic core interdigitated electrode optical calibration system, characterized by, Comprising: An optical / electronic microscope measurement unit with a resolution of ≥0.1 μm, a magnification of 500-1000 times, a field of view of ≥100 μm×100 μm, and a gray-scale image acquisition supporting 12-bit pixel depth, for capturing the edge of the ceramic interdigital electrode and obtaining sub-pixel level image details; A precision motion platform with a positioning accuracy of ±1 μm, a repeat positioning accuracy of ±0.5 μm, a stroke of ≥60 mm×5 mm, and support for linear scanning and point positioning, for driving the ceramic core to move along a preset path to realize uniform sampling of the entire length of the electrode; An image acquisition and processing module with a frame rate of ≥15 fps, integrated Gaussian filtering, OTSU binarization, and Zernike moment edge detection algorithms, for real-time processing of image noise and accurate positioning of electrode edge coordinates; A data processing module for performing three-level outlier processing and weighted truncated average algorithm to calculate the calibration value of the ceramic interdigital electrode; A laser engraving unit with an engraving accuracy of ±0.1 mm, an engraving depth of ≤0.1 mm, and support for character and number output, for engraving the calibration value on the non-electrode area of the ceramic core; A data storage and interaction module integrated with an MES system interface, supporting two-dimensional code scanning, for storing the original image, calibration parameters, and quality indicators of the ceramic core, and realizing the association of ceramic core data with the production system. ​

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