Crystal ingot appearance inspection method

Abstract

The application discloses a kind of crystal ingot appearance detection methods, belong to crystal ingot appearance detection technical field.The method includes: vertically placing crystal ingot on rotating bearing platform and rotating, preliminary judgment is uploaded MES system by scanning and uploading appearance scanning device and is broken, preliminary judgment of grey skin;The weight, geometric parameter and grinding mark roughness of preliminary qualified crystal ingot are surveyed and mapped using laser scanning device;Based on measurement data, construct crystal ingot three-dimensional digital model, form grid three-dimensional model according to rotation angle every 3 °, height every 1 cm partition, then it is unfolded into grid two-dimensional plane model;Finally, upload MES system, according to preset standard, judge each partition data point, output detection result.The application converts three-dimensional detection into two-dimensional plane analysis, realizes automatic evaluation in combination with MES system, effectively improves the detection efficiency, avoids the difference of artificial subjectivity at the same time, improves the consistency and reliability of detection.

Description

Technical Field

[0001] This invention belongs to the field of crystal ingot appearance inspection technology, and specifically relates to a method for crystal ingot appearance inspection. Background Technology

[0002] Monocrystalline silicon is the fundamental material for manufacturing semiconductor chips and photovoltaic cells. After crystal growth and grinding, the ingot needs to enter the slicing process. To ensure slicing quality and final chip yield, strict testing must be performed on multiple indicators of the ingot before slicing, including length, diameter, roundness, taper, surface cracks, chipping, pits, oxide layer, color uniformity, and roughness.

[0003] For example, the prior art with patent number 202110856396.X and invention title: "Detection Device" provides the following technical solution: The detection device includes a support, a tank, and a rotating mechanism. The support has the tank for placing the crystal ingot to be tested. The rotating mechanism is located in the tank and is used to support the crystal ingot to be tested. A driving mechanism is used to drive the rotating mechanism to rotate, so that the rotating mechanism drives the crystal ingot to be tested to rotate. Therefore, when performing appearance quality inspection of crystal ingots, the crystal ingot to be tested can be placed in the tank, so that the side of the crystal ingot supports the rotating mechanism. The driving mechanism drives the rotating mechanism to rotate, and the rotating mechanism can drive the crystal ingot to be tested to rotate, so that the ultraviolet lamp irradiates different areas of the side of the crystal ingot to be tested.

[0004] The aforementioned technology uses a mechanical structure to rotate the crystal ingot, avoiding direct contact between the worker's hands and ultraviolet light, thus preventing hand injuries and enhancing safety. However, the following technical problems exist: Inspecting a single large-sized crystal ingot requires multiple people working together and multiple rotations, with each ingot taking 20-60 minutes, resulting in low inspection efficiency; furthermore, manual inspection is highly subjective, with judgments relying on the worker's experience, leading to significant differences in judgment results among workers with varying levels of experience. Summary of the Invention

[0005] In view of this, the present invention provides a method for inspecting the appearance of crystal ingots to solve the technical problems of low efficiency, large discrepancies in judgment results, and high false negative rate in the prior art.

[0006] The technical solution adopted by this invention to solve its technical problem is:

[0007] A method for inspecting the appearance of crystal ingots includes the following steps:

[0008] S1. Place the crystal ingot to be tested vertically on the rotating bearing platform with one end face as the reference, control the rotating bearing platform to rotate at a predetermined speed, use the appearance scanning device to scan the appearance of the crystal ingot to be tested, and upload the scanning results to the MES system to make a preliminary judgment on the appearance damage and gray skin of the crystal ingot to be tested, and obtain a crystal ingot that initially meets the standard.

[0009] S2. Use a laser scanning device to scan and map the target parameters of the ingot that initially meets the standard, so as to obtain measurement data including the weight data, geometric parameter data and surface roughness data of the ingot that initially meets the standard.

[0010] S3. Based on the measurement data, construct a preliminary three-dimensional digital model of the crystal ingot that conforms to the standard to obtain a three-dimensional digital model of the crystal ingot. Set up partitions according to the crystal ingot rotation angle of 3° and the crystal ingot height of 1cm to obtain a gridded three-dimensional digital model of the crystal ingot. Expand the above gridded three-dimensional digital model of the crystal ingot into a gridded two-dimensional planar model of the crystal ingot through geometric transformation.

[0011] S4. Upload the gridded ingot two-dimensional plane model to the MES system. The MES system judges each data point in each partition of the gridded ingot two-dimensional plane model according to the predetermined standard and outputs the test results. The predetermined standard is that the deviation of the ingot radius data measured by CCD within the data point is ≥0.5mm and the data point is unqualified. The number of unqualified data points in the partition is ≥5 and the ingot is unqualified.

[0012] Preferably, the appearance scanning device in step S1 includes: a line scan camera, a laser profilometer or a structured light profilometer. The line scan camera is configured with defect judgment criteria: a length greater than 2mm and a width greater than 2mm are considered defects. The laser profilometer or structured light profilometer has a detection resolution of 0.1mm and a typical threshold setting of 0.4mm.

[0013] Preferably, the rotating bearing platform in step S1 is equipped with a safety structure to prevent the crystal ingot from tipping over. After the safety structure is activated, the crystal ingot to be tested can be fixed to prevent it from tipping over during the surveying process.

[0014] Preferably, the predetermined speed of rotation of the rotating bearing platform in step S1 is 20 seconds / revolution.

[0015] Preferably, the laser scanning device in step S2 includes: a laser displacement sensor, a CCD diameter measuring instrument, and a 3D line laser measuring instrument.

[0016] Preferably, the 3D line laser measuring instrument uses a single controller in conjunction with two probes to scan a 500mm long crystal rod in one go, achieving complete coverage of the measured surface with a single rotation.

[0017] Preferably, step S3 specifically includes:

[0018] S31. Clean, denoise, and format the measurement data to obtain preprocessed data;

[0019] S32. Based on the preprocessed data, with the center of the rotation axis of the lower end face of the crystal ingot as the origin of the coordinate system, the measurement direction of the 3D line laser measuring instrument is the X-axis direction, the stepping direction of the 3D line laser measuring instrument is the Y-axis direction, the laser displacement sensor moves from the lower end face of the crystal ingot upwards to the upper end face of the crystal ingot in the Z-axis direction, the measurement data of the 3D line laser measuring instrument is the X-axis coordinate, the stepping physical interval of the 3D line laser measuring instrument is the Y-axis coordinate, and the travel distance of the laser displacement sensor moving from the lower end face of the crystal ingot upwards to the upper end face of the crystal ingot is the Z-axis coordinate. Based on the above coordinate axes, the scanning results are used to generate a three-dimensional graphic using programming software to obtain a three-dimensional digital model of the crystal ingot.

[0020] S33. Divide the ingot into sections according to the rotation angle of the ingot along the Y-axis by 3° and the height of the ingot along the Z-axis by 1cm to obtain a gridded three-dimensional digital model of the ingot.

[0021] S34. Using the 0° longitudinal generatrix passing through the axis as a virtual cutting reference, the three-dimensional digital model of the gridded ingot is unfolded in a rectangular planar view with the Y-axis and circumferential arc length as coordinate systems. Equal angle and equal distance latitude and longitude grid partitions are superimposed, and visualization rendering or feature enhancement is performed to highlight key structures such as edges and contours, so as to obtain a two-dimensional planar model of the gridded ingot.

[0022] Preferably, in step S32, the programming software is Python.

[0023] Preferably, in step S4, the data points include: the ingot radius data measured by the CCD diameter meter, the rotation angle of the ingot, and the coordinates of the movement of the laser displacement sensor.

[0024] Preferably, the method further includes the following steps: performing surface defect enhancement detection based on spectral fusion on the preliminarily compliant crystal ingot. By utilizing the differences in sensitivity of different wavelengths to microcracks, stress layers, polymorphic inclusions, and heavy metal contamination on the crystal surface, image fusion and differential analysis are performed, which can simultaneously detect subsurface damage and surface micro-defects. In particular, it has outstanding identification ability for tiny inclusions inside transparent or semi-transparent crystal ingots, avoiding the problem of insufficient defect contrast under a single light source.

[0025] The aforementioned ingot appearance inspection method uses an appearance scanning device to scan for surface damage and surface defects on the ingots. The scanning results are uploaded to the MES system, which then assesses the damage and surface defects, improving the efficiency of ingot appearance inspection. A laser scanning device is used to scan and map the ingot weight, geometric parameters, and surface roughness. Compared to manual inspection, this provides more comprehensive data and prevents missed detections. The obtained data is used to create a 3D digital model in a grid format. Through geometric transformation, this model is expanded into a gridded 2D planar model of the ingot, converting 3D spatial analysis into 2D planar analysis. The results are uploaded to the MES system, which then performs point-by-point or zone-by-zone screening on the gridded 2D planar model, calculating and determining whether the ingot diameter meets the set standards, and outputting the inspection conclusion. Utilizing the MES system improves the efficiency of ingot appearance inspection while reducing subjective human judgment, thereby improving the consistency and reliability of the inspection. The set acceptance standards can be adjusted for ingots of different materials, sizes, and shapes, increasing the types of ingots that can be inspected. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the surface damage of the crystal ingot to be tested obtained in an embodiment of the present invention.

[0027] Figure 2 This is a schematic diagram illustrating the initial assessment of the appearance damage of the crystal ingot by the MES system obtained in this embodiment of the invention.

[0028] Figure 3 This is a schematic diagram of the scanning process of the laser scanning device in an embodiment of the present invention.

[0029] Figure 4 This is a 3D model of a cylinder generated by 3D reconstruction in a mesh format, obtained in an embodiment of the present invention. Detailed Implementation

[0030] To facilitate understanding of this application, a more complete description of the application will be provided below in conjunction with the accompanying drawings and embodiments. This application can be implemented in many different embodiments and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this application.

[0031] A method for inspecting the appearance of crystal ingots, specifically including the following steps:

[0032] S1. The ingot to be inspected is placed vertically on the rotating bearing platform with one end face as the reference. The rotating bearing platform is controlled to rotate at 20 seconds / revolution. The appearance of the ingot to be inspected is scanned using a line scan camera and a laser profilometer. The defect is judged according to the criteria that the length is greater than 2mm and the width is greater than 2mm. The scanning results are uploaded to the MES system to make a preliminary judgment on the appearance damage and gray skin of the ingot to be inspected, and to obtain an ingot that initially meets the standard. The rotating bearing platform is equipped with a safety structure to prevent the ingot from tipping over. After the safety structure is opened, the ingot to be inspected can be fixed to prevent it from tipping over during the surveying process.

[0033] S2. Use a laser displacement sensor, CCD diameter measuring instrument, and 3D line laser measuring instrument to scan and map the target parameters of the ingot that initially meets the standard, so as to obtain measurement data including the weight data, geometric parameter data, and surface roughness data of the ingot that initially meets the standard.

[0034] S3. Based on the measurement data, construct a preliminary three-dimensional digital model of the crystal ingot that conforms to the standard to obtain a three-dimensional digital model of the crystal ingot. Set up partitions according to the crystal ingot rotation angle of 3° and the crystal ingot height of 1cm to obtain a gridded three-dimensional digital model of the crystal ingot. Expand the above gridded three-dimensional digital model of the crystal ingot into a gridded two-dimensional planar model of the crystal ingot through geometric transformation.

[0035] S4. Upload the gridded ingot two-dimensional plane model to the MES system. The MES system judges each data point in each partition of the gridded ingot two-dimensional plane model according to predetermined standards and outputs the test results. The predetermined standards are: a data point with a deviation of ≥0.5mm in the ingot radius data measured by the CCD diameter meter is a non-qualified data point; a partition with ≥5 non-qualified data points is a non-qualified ingot. The data points include: the ingot radius data measured by the CCD diameter meter, the rotation angle of the ingot, and the coordinates of the laser displacement sensor movement.

[0036] Furthermore, the 3D line laser measuring instrument uses a single controller in conjunction with two probes to scan a 500mm long crystal rod in one go, achieving complete coverage of the measured surface with a single rotation.

[0037] Furthermore, step S3 specifically includes:

[0038] S31. Clean, denoise, and format the measurement data to obtain preprocessed data;

[0039] S32. Based on the preprocessed data, with the center of the rotation axis of the lower end face of the crystal ingot as the origin of the coordinate system, the measurement direction of the 3D line laser measuring instrument is the X-axis direction, the stepping direction of the 3D line laser measuring instrument is the Y-axis direction, the laser displacement sensor moves from the lower end face of the crystal ingot upwards to the upper end face of the crystal ingot in the Z-axis direction, the measurement data of the 3D line laser measuring instrument is the X-axis coordinate, the stepping physical interval of the 3D line laser measuring instrument is the Y-axis coordinate, and the travel distance of the laser displacement sensor moving from the lower end face of the crystal ingot upwards to the upper end face of the crystal ingot is the Z-axis coordinate. Based on the above coordinate axes, the scanning results are used to generate a three-dimensional graphic using Python software to obtain a three-dimensional digital model of the crystal ingot.

[0040] S33. Divide the ingot into sections according to the rotation angle of the ingot along the Y-axis by 3° and the height of the ingot along the Z-axis by 1cm to obtain a gridded three-dimensional digital model of the ingot.

[0041] S34. Using the 0° longitudinal generatrix passing through the axis as a virtual cutting reference, the three-dimensional digital model of the gridded ingot is unfolded in a rectangular planar view with the Y-axis and circumferential arc length as coordinate systems. Equal angle and equal distance latitude and longitude grid partitions are superimposed, and visualization rendering or feature enhancement is performed to highlight key structures such as edges and contours, so as to obtain a two-dimensional planar model of the gridded ingot.

[0042] Furthermore, the method includes the following steps: performing surface defect enhancement detection based on spectral fusion on preliminarily compliant crystal ingots. By utilizing the differences in sensitivity of different wavelengths to microcracks, stress layers, polymorphic inclusions, and heavy metal contamination on the crystal surface, image fusion and differential analysis are performed. This method can simultaneously detect subsurface damage and surface micro-defects, and has a particularly outstanding ability to identify tiny inclusions inside transparent or semi-transparent crystal ingots, avoiding the problem of insufficient defect contrast under a single light source.

[0043] To facilitate understanding of the technical concept and patentability of this application, the following embodiments are further provided:

[0044] Example 1

[0045] A method for inspecting the appearance of a 12-inch crystal ingot, specifically including the following steps:

[0046] S1. The 12-inch crystal ingot to be inspected is placed vertically on the rotating bearing platform with one end face as the reference. The rotating bearing platform is controlled to rotate at 20 seconds / revolution. The appearance of the 12-inch crystal ingot to be inspected is scanned using a line scan camera and a laser profilometer. According to the judgment criteria that the length is greater than 2mm and the width is greater than 2mm, the scanning results are uploaded to the MES system to make a preliminary judgment on the appearance damage and gray skin of the 12-inch crystal ingot to be inspected, and to obtain a 12-inch crystal ingot that initially meets the standard. The rotating bearing platform is equipped with a safety structure to prevent the crystal ingot from tipping over. After the safety structure is opened, the crystal ingot to be inspected can be fixed to prevent it from tipping over during the surveying process.

[0047] S2. Use a laser displacement sensor, CCD diameter measuring instrument, and 3D line laser measuring instrument to scan and map the target parameters of the 12-inch ingot that initially meets the standard, so as to obtain measurement data including the weight data, geometric parameter data, and surface roughness data of the 12-inch ingot that initially meets the standard.

[0048] S3. Based on the measurement data, construct a preliminary three-dimensional digital model of a 12-inch crystal ingot that conforms to the standard to obtain a three-dimensional digital model of a 12-inch crystal ingot. Set partitions according to the crystal ingot rotation angle of 3° and the crystal ingot height of 1cm to obtain a gridded three-dimensional digital model of a 12-inch crystal ingot. Expand the above gridded three-dimensional digital model of a 12-inch crystal ingot into a gridded two-dimensional planar model of a 12-inch crystal ingot through geometric transformation.

[0049] S4. Upload the gridded 12-inch ingot 2D planar model to the MES system. The MES system judges each data point in each partition of the gridded 12-inch ingot 2D planar model according to predetermined standards and outputs the test results. The standard diameter of the 12-inch ingot is 301mm. The predetermined standard is that a deviation of ≥0.5mm in the ingot radius data measured by the CCD diameter within a data point is considered an unqualified data point, and a partition with ≥5 unqualified data points is considered an unqualified ingot. The data points include: the 12-inch ingot radius data measured by the CCD diameter meter, the rotation angle of the ingot, and the coordinates of the laser displacement sensor movement.

[0050] Furthermore, the 3D line laser measuring instrument uses a single controller in conjunction with two probes to scan a 500mm long crystal rod in one go, achieving complete coverage of the measured surface with a single rotation.

[0051] Furthermore, step S3 specifically includes:

[0052] S31. Clean, denoise, and format the measurement data to obtain preprocessed data;

[0053] S32. Based on the preprocessed data, with the center of the rotation axis of the lower end face of the crystal ingot as the origin of the coordinate system, the measurement direction of the 3D line laser measuring instrument is the X-axis direction, the stepping direction of the 3D line laser measuring instrument is the Y-axis direction, the laser displacement sensor moves from the lower end face of the crystal ingot upwards to the upper end face of the crystal ingot in the Z-axis direction, the measurement data of the 3D line laser measuring instrument is the X-axis coordinate, the stepping physical interval of the 3D line laser measuring instrument is the Y-axis coordinate, and the travel distance of the laser displacement sensor moving from the lower end face of the crystal ingot upwards to the upper end face of the crystal ingot is the Z-axis coordinate. Based on the above coordinate axes, the scanning results are used to generate a three-dimensional graphic using Python software to obtain a three-dimensional digital model of the crystal ingot.

[0054] S33. Divide the ingot into sections according to the rotation angle of the ingot along the Y-axis by 3° and the height of the ingot along the Z-axis by 1cm to obtain a gridded 12-inch ingot three-dimensional digital model.

[0055] S34. Using the 0° longitudinal generatrix passing through the axis as a virtual cutting reference, the 3D digital model of the gridded 12-inch crystal ingot is unfolded in a rectangular planar view with the Y-axis and circumferential arc length as coordinate systems. Equal angle and equal distance latitude and longitude grid partitions are superimposed, and visualization rendering or feature enhancement is performed to highlight key structures such as edges and contours, so as to obtain a 2D planar model of the gridded 12-inch crystal ingot.

[0056] Furthermore, the process includes the following steps: performing surface defect enhancement detection based on spectral fusion on 12-inch ingots that initially meet the standards. By utilizing the differences in sensitivity of different wavelengths to microcracks, stress layers, polymorphic inclusions, and heavy metal contamination on the crystal surface, image fusion and differential analysis are performed, which can simultaneously detect subsurface damage and surface micro-defects. In particular, it has outstanding identification capabilities for tiny inclusions inside transparent or semi-transparent ingots, avoiding the problem of insufficient defect contrast under a single light source.

[0057] In summary, this invention provides a method for inspecting the appearance of a crystal ingot. The rotating platform is controlled to rotate at a rate of 20 seconds per revolution. A line scan camera and a laser profilometer are used to scan the appearance of a 12-inch crystal ingot, and the scan results are obtained. Please refer to [the provided text]. Figure 1 , Figure 1 This diagram illustrates the surface damage of the ingot to be inspected in this embodiment. The length and width of the damaged area can be determined by scanning with a line scan camera and a laser profilometer. The scan data is then uploaded to the MES system. Please refer to [link / reference needed]. Figure 2 , Figure 2 This is a schematic diagram illustrating the preliminary assessment of the surface damage of the ingot by the MES system in this embodiment. The MES system performs a preliminary assessment of the location, length, and width of each damage point on the ingot. By utilizing the MES system to make a preliminary judgment on the damage and surface defects of the ingot, it replaces manual inspection and improves the efficiency of ingot surface inspection. A laser displacement sensor, a CCD diameter measuring instrument, and a 3D line laser measuring instrument are used to scan and map a 12-inch ingot that initially meets the standards. Please refer to [link / reference]. Figure 3 , Figure 3This is a schematic diagram of the scanning process of the laser scanning device obtained in an embodiment of the present invention. The laser displacement sensor measures the length of the 12-inch ingot that initially meets the standard, the CCD diameter measuring instrument measures the diameter of the 12-inch ingot that initially meets the standard, and the 3D line laser measuring instrument measures the surface roughness of the 12-inch ingot that initially meets the standard. The obtained data is used with the center of the rotation axis of the lower end face of the ingot as the origin of the coordinate system. The measurement direction of the 3D line laser measuring instrument is the X-axis, the stepping direction of the 3D line laser measuring instrument is the Y-axis, and the movement direction of the laser displacement sensor from the lower end face of the ingot to the upper end face of the ingot is the Z-axis. The measurement data of the 3D line laser measuring instrument is the X-axis coordinate, the stepping physical interval of the 3D line laser measuring instrument is the Y-axis coordinate, and the travel distance of the laser displacement sensor from the lower end face of the ingot to the upper end face of the ingot is the Z-axis coordinate. Based on the above coordinate axes, the scanning results are used to generate a 3D graphic using programming software to obtain a 3D digital model of the ingot. Furthermore, partitions are set according to the rotation angle of the ingot along the Y-axis at 3° intervals and the height of the ingot along the Z-axis at 1cm intervals to obtain a gridded 3D digital model of the ingot. Please refer to [link / reference needed]. Figure 4 , Figure 4 The 12-inch ingot 3D model obtained in this embodiment of the invention is constructed in a gridded form. Then, using the 0° longitudinal generatrix passing through the axis as a virtual cutting reference, the 12-inch ingot 3D digital model is unfolded in a rectangular planar view with the Y-axis and circumferential arc length as coordinate systems. Equal angle and equal spacing latitude and longitude grids are superimposed, and visualization rendering or feature enhancement is performed to highlight key structures such as edges and contours to obtain a gridded ingot 2D planar model. The gridded ingot 2D planar model is uploaded to the MES system, and the MES system judges each data point in each partition of the gridded ingot 2D planar model according to a predetermined standard and outputs the detection results. The predetermined standard is that the deviation of the ingot radius data measured by CCD within the data point is ≥0.5mm, which is a non-qualified data point, and the number of non-qualified data points in the partition is ≥5, which is a non-qualified ingot. By using the above-mentioned ingot appearance inspection method, the detection efficiency can be improved, while avoiding the problem of large differences in judgment results due to reliance on human work experience.

[0058] The above description discloses only preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Those skilled in the art will understand that implementing all or part of the processes of the above embodiments and making equivalent changes in accordance with the claims of the present invention are still within the scope of the present invention.

Claims

1. A method for inspecting the appearance of crystal ingots, characterized in that... Includes the following steps: S1. Place the crystal ingot to be tested vertically on the rotating bearing platform with one end face as the reference, control the rotating bearing platform to rotate at a predetermined speed, use the appearance scanning device to scan the appearance of the crystal ingot to be tested, and upload the scanning results to the MES system to make a preliminary judgment on the appearance damage and gray skin of the crystal ingot to be tested, and obtain a crystal ingot that initially meets the standard. S2. Use a laser scanning device to scan and map the target parameters of the ingot that initially meets the standard, so as to obtain measurement data including the weight data, geometric parameter data and surface roughness data of the ingot that initially meets the standard. S3. Based on the measurement data, construct a preliminary three-dimensional digital model of the crystal ingot that conforms to the standard to obtain a three-dimensional digital model of the crystal ingot. Set up partitions according to the crystal ingot rotation angle of 3° and the crystal ingot height of 1cm to obtain a gridded three-dimensional digital model of the crystal ingot. Expand the above gridded three-dimensional digital model of the crystal ingot into a gridded two-dimensional planar model of the crystal ingot through geometric transformation. S4. Upload the gridded ingot two-dimensional plane model to the MES system. The MES system judges each data point in each partition of the gridded ingot two-dimensional plane model according to the predetermined standard and outputs the test results. The predetermined standard is that the deviation of the ingot radius data measured by CCD within the data point is ≥0.5mm and the data point is unqualified. The number of unqualified data points in the partition is ≥5 and the ingot is unqualified.

2. The method for inspecting the appearance of crystal ingots according to claim 1, characterized in that, The appearance scanning device in step S1 includes: a line scan camera, a laser profilometer or a structured light profilometer. The line scan camera is configured with defect judgment criteria: a length greater than 2mm and a width greater than 2mm are considered defects. The laser profilometer or structured light profilometer has a detection resolution of 0.1mm and a typical threshold setting of 0.4mm.

3. The method for inspecting the appearance of crystal ingots according to claim 1, characterized in that, The rotating bearing platform in step S1 is equipped with a safety structure to prevent the crystal ingot from tipping over. After the safety structure is activated, the crystal ingot to be tested can be fixed to prevent it from tipping over during the surveying process.

4. The method for inspecting the appearance of crystal ingots according to claim 1, characterized in that, The predetermined speed of rotation of the rotating bearing platform in step S1 is 20 seconds per revolution.

5. The method for inspecting the appearance of crystal ingots according to claim 1, characterized in that, The laser scanning device in step S2 includes: a laser displacement sensor, a CCD diameter measuring instrument, and a 3D line laser measuring instrument.

6. The method for inspecting the appearance of crystal ingots according to claim 1, characterized in that, The 3D line laser measuring instrument uses a single controller in conjunction with two probes to scan a 500mm long crystal rod in one go, achieving complete coverage of the measured surface with a single rotation.

7. The method for inspecting the appearance of crystal ingots according to claim 1, characterized in that, Step S3 is as follows: S31. Clean, denoise, and format the measurement data to obtain preprocessed data; S32. Based on the preprocessed data, with the center of the rotation axis of the lower end face of the crystal ingot as the origin of the coordinate system, the measurement direction of the 3D line laser measuring instrument is the X-axis direction, the stepping direction of the 3D line laser measuring instrument is the Y-axis direction, the laser displacement sensor moves from the lower end face of the crystal ingot upwards to the upper end face of the crystal ingot in the Z-axis direction, the measurement data of the 3D line laser measuring instrument is the X-axis coordinate, the stepping physical interval of the 3D line laser measuring instrument is the Y-axis coordinate, and the travel distance of the laser displacement sensor moving from the lower end face of the crystal ingot upwards to the upper end face of the crystal ingot is the Z-axis coordinate. Based on the above coordinate axes, the scanning results are used to generate a three-dimensional graphic using programming software to obtain a three-dimensional digital model of the crystal ingot. S33. Divide the ingot into sections according to the rotation angle of the ingot along the Y-axis by 3° and the height of the ingot along the Z-axis by 1cm to obtain a gridded three-dimensional digital model of the ingot. S34. Using the 0° longitudinal generatrix passing through the axis as a virtual cutting reference, the three-dimensional digital model of the gridded ingot is unfolded in a rectangular planar view with the Y-axis and circumferential arc length as coordinate systems. Equal angle and equal distance latitude and longitude grid partitions are superimposed, and visualization rendering or feature enhancement is performed to highlight key structures such as edges and contours, so as to obtain a two-dimensional planar model of the gridded ingot.

8. The method for inspecting the appearance of crystal ingots according to claim 5, characterized in that, In step S32, the programming software is Python.

9. The method for inspecting the appearance of crystal ingots according to claim 1, characterized in that, In step S4, the data points include: the ingot radius data measured by the CCD diameter meter, the rotation angle of the ingot, and the coordinates of the movement of the laser displacement sensor.

10. The method for inspecting the appearance of crystal ingots according to claim 1, characterized in that, It also includes the following steps: The method utilizes spectral fusion to enhance the detection of surface defects in ingots that initially meet the standards. By leveraging the differences in sensitivity of different wavelengths to microcracks, stress layers, polymorphic inclusions, and heavy metal contamination on the crystal surface, image fusion and differential analysis are performed. This method can simultaneously detect subsurface damage and surface micro-defects, and has a particularly outstanding ability to identify tiny inclusions inside transparent or semi-transparent ingots, avoiding the problem of insufficient defect contrast under a single light source.

Images