An automated multifunctional calibration device and method for spectral confocal displacement sensors

Abstract

The present invention is an automated multifunctional calibration device and method for a spectral confocal displacement sensor, comprising a laser interferometer, wherein a laser feedback module is provided in the emission light path of the laser interferometer; the laser feedback module is disposed on a first electric motion stage, wherein a linear calibration reflector is provided on the first electric motion stage, and the first electric motion stage controls the synchronous movement of the linear calibration reflector and the laser feedback module; a second electric motion stage is provided on one side of the first electric motion stage, which is perpendicular to the first electric motion stage, and a probe horizontal angle adjustment stage is provided for movement control on the second electric motion stage; and a spectral confocal probe is disposed on the probe horizontal angle adjustment stage or the probe fixing stage. The present invention implements calibration of the linear error, limit measurement angle, and spot size parameters of the spectral confocal probe in the same calibration system, and the transformation of the probe posture is achieved through electric control, thereby improving the automation level and calibration efficiency of the probe calibration.

Description

Technical Field

[0001] The present invention relates to the field of precision measurement and sensing technology, and in particular to an automated multifunctional calibration device and method for a spectral confocal displacement sensor. Background Art

[0002] Spectral confocal displacement sensors are widely used in industrial inspection applications such as distance measurement, thickness measurement, and topography measurement. Typical applications include wafer surface inspection, glass thickness measurement, roughness measurement, and lens profile detection. Spectral confocal displacement sensors offer advantages such as high precision, non-contact operation, and adaptability to materials with varying reflectivity. However, in actual measurement, the sensor's spot size and the maximum measurable angle when measuring curved surfaces significantly impact its effectiveness. Furthermore, during probe assembly and dispensing, the non-repeatability of technicians' operations can lead to deviations in the lens position of different probes, resulting in differences in the measurement optical path and inaccurate measurement results.

[0003] To ensure the measurement accuracy and performance of spectral confocal displacement sensors, high-precision instruments are required, and efficient calibration methods are used to calibrate the sensor's linear error, spot size, and limit measurement angle. Traditional calibration methods can only calibrate linear error during a single calibration. Calibration of spot size and limit measurement angle requires the probe to be disassembled and calibrated with additional instruments. The diversity of calibration parameters and the complexity of the calibration process greatly limit the production efficiency of spectral confocal displacement sensors. In addition, probes with different ranges and measurement angles have different sizes. In order to accommodate spectral confocal sensors of different sizes, the probe clamping device and probe posture adjustment device must also be universal and interchangeable. Summary of the Invention

[0004] The purpose of the present invention is to overcome the problems existing in the prior art and provide an automated multifunctional calibration device and method for a spectral confocal displacement sensor. In the same calibration system, the calibration of multiple parameters of the spectral confocal probe is completed. When calibrating different parameters of the spectral confocal probe, the transformation of the probe posture is achieved through electric control, which greatly improves the degree of automation of the probe calibration and the work efficiency of the calibration technicians.

[0005] In order to achieve the above technical objectives and the above technical effects, the present invention is implemented through the following technical solutions:

[0006] An automated multifunctional calibration device for a spectral confocal displacement sensor, comprising:

[0007] A laser interferometer, wherein a laser feedback module is provided on the emission light path of the laser interferometer so that the laser emitted by the laser interferometer is returned by the laser feedback module to measure the position of the laser feedback module;

[0008] The laser feedback module is arranged on a first electric motion platform and is controlled to move by the first electric motion platform. A linear calibration reflector is provided on the first electric motion platform, and the first electric motion platform controls the linear calibration reflector to move synchronously with the laser feedback module, so that the positions of the laser feedback module and the linear calibration reflector are relatively fixed;

[0009] The linear calibration reflector reflects the white light emitted by the spectral confocal probe to characterize the displacement measurement value of the spectral confocal probe and achieve comparison with the displacement measurement value of the laser interferometer;

[0010] A second electric motion platform is provided on one side of the first electric motion platform and is perpendicular to the first electric motion platform. A probe horizontal angle adjustment platform is movable and controlled on the second electric motion platform.

[0011] The spectral confocal probe:

[0012] It is installed on the probe horizontal angle adjustment platform and its rotation is controlled by the probe horizontal angle adjustment platform, and is used for extreme angle measurement and spot size measurement;

[0013] Or it can be set on the probe fixing table for linear calibration.

[0014] Furthermore, an extreme angle calibration platform is provided on the outer side of the probe horizontal angle adjustment platform. When measuring the extreme angle, the probe horizontal angle adjustment platform adjusts the light outlet of the spectral confocal probe to align with the extreme angle calibration platform. A calibration checkerboard is provided on the inner side of the probe horizontal angle adjustment platform, and the calibration checkerboard is controlled by the first electric motion platform to move in a direction perpendicular to the second electric motion platform. After the extreme angle measurement is completed, the probe horizontal angle adjustment platform controls the rotation degree of the spectral confocal probe so that its light outlet is aligned with the calibration checkerboard, so that the calibration checkerboard can return the spectral confocal probe measurement beam to perform spot size measurement.

[0015] Furthermore, the probe fixing platform is arranged at the outer end of the first electric motion platform, so that the laser interferometer, laser feedback module, linear calibration reflector, and spectral confocal probe are located on the same straight line, and the measurement beam of the laser interferometer is collinear with the measurement beam of the spectral confocal probe for linear calibration.

[0016] Furthermore, the extreme angle calibration platform is rotatably arranged on a corresponding frame, so that the angle of the extreme angle calibration platform relative to the spectral confocal probe is adjustable.

[0017] Furthermore, the probe fixing platform clamps the spectral confocal probe through the V-shaped groove provided thereon, so as to be suitable for spectral confocal probes of different lengths and diameters.

[0018] Furthermore, the spectral confocal probe is communicatively connected to the spectral confocal controller via an optical fiber, and the spectral confocal controller is communicatively connected to the host computer via a network for data acquisition. The host computer is respectively connected to the first electric motion stage, the second electric motion stage, the probe horizontal angle adjustment stage, the extreme angle calibration stage and the laser interferometer for controlling the corresponding actions to adjust the posture.

[0019] A detection method using a multifunctional automated calibration device for a spectral confocal displacement sensor, the method comprising limit angle measurement and spot size measurement, wherein:

[0020] The limit angle measurement method is as follows: when the optical axis of the spectral confocal probe is not perpendicular to the limit angle calibration platform, the maximum angle that the limit angle calibration platform can rotate relative to the vertical position is the limit angle, the host computer controls the rotation of the limit angle calibration platform, and at the same time sends an instruction to the spectral confocal controller to read the displacement measurement data. When the measurement data of the spectral confocal controller jumps to an invalid value, the host computer reads the angle of the limit angle calibration platform. ,angle This is the limit measurement angle of the spectral confocal probe;

[0021] The spot size measurement method is as follows: a calibration checkerboard is controlled by a first electric motion stage to move in a direction perpendicular to the optical axis of the spectral confocal probe, and a host computer sends an instruction to the spectral confocal controller to read the light intensity. The calibration checkerboard consists of black and white squares. The spectral confocal probe measures the light beam, and the light intensities reflected by the squares of different colors on the calibration checkerboard are different. The spot size is measured and calibrated based on the jump in light intensity at the junction of black and white squares.

[0022] Furthermore, the method also includes linear calibration, and the linear calibration method is:

[0023] First, the spectral confocal probe is fixed on the probe fixing platform so that the measuring beam of the spectral confocal probe is collinear with the measuring beam of the laser interferometer. The first motorized motion stage controls the linear calibration mirror to move along the measuring beam of the spectral confocal probe. The peak positioning algorithm is used as the positioning criterion to determine whether a valid measurement peak is detected. The linear calibration mirror is positioned at the near end and far end of the measuring range of the spectral confocal probe.

[0024] After locating the near and far ends of the spectral confocal probe's range, the midpoint between the far and near ends is used as the zero point, and the measurement values of the laser interferometer and the spectral confocal probe are reset to zero. Then, the linear calibration mirror is controlled by the first electric motion stage to move to the near end of the spectral confocal probe's range. The step distance of the first electric motion stage is set to d, the movement speed is set to v, and the actual range of the spectral confocal probe is taken as D. Then, n = D / d measurement positions are sampled within the full range of the probe during the scanning process.

[0025] The host computer controls the first electric motion stage to move step by step from the near end of the measuring range to the far end of the measuring range. Each time it steps to a measuring point, the host computer samples the spectral confocal controller and the laser interferometer and saves the samples to the host computer.

[0026] After the full-range scan is completed, the displacement measurement deviations of the spectral confocal probe and the laser interferometer at n sampling points are obtained.

[0027] Furthermore, after obtaining the displacement measurement values of the spectral confocal probe and the laser interferometer at all sampling points, a nonlinear relationship between the displacement measurement values of the spectral confocal probe and the displacement measurement values of the laser interferometer is obtained by spline curve fitting. Then, equal-interval sampling is performed between the near end and the far end of the spectral confocal probe range. A mapping calibration table between the displacement measurement values of the spectral confocal probe and the displacement measurement values of the laser interferometer is generated through the nonlinear relationship. The mapping calibration table is uploaded to the spectral confocal controller, thereby greatly improving the measurement accuracy of the spectral confocal displacement sensor.

[0028] The beneficial effects of the present invention are:

[0029] The present invention realizes the calibration of the linear error, limit measurement angle, and spot size parameters of the spectral confocal probe in the same calibration system. The transformation of the probe posture is achieved through electric control. The position or angle of the electric control calibration mechanism can be fed back to the host computer, which greatly improves the automation level of probe calibration and the work efficiency of calibration technicians.

[0030] The linear error calibration result can generate a mapping calibration table as compensation for the displacement measurement value of the spectral confocal sensor, thereby greatly improving the measurement accuracy of the spectral confocal displacement sensor.

[0031] The extreme measurement angle calibration results can be used as a reference for the normal direction adjustment range when the spectral confocal sensor measures the surface topography.

[0032] The spot size calibration results can be used as a reference for the lateral resolution of spectral confocal sensors in measuring roughness, micro-groove depth, and other scenarios.

[0033] Multiple parameters of the spectral confocal probe can be calibrated in the same system, and the parameter calibration results can be used to provide timely feedback on whether there are any problems with the spectral confocal probe assembly, effectively improving the yield rate of spectral confocal probe production. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a schematic diagram of the principle of the automated multifunctional calibration device for spectral confocal sensors;

[0035] Figure 2 This is a schematic diagram of the structure of an automated multifunctional calibration device for spectral confocal sensors;

[0036] Figure 3 This is a schematic diagram of the limit angle calibration principle of the spectral confocal displacement sensor;

[0037] Figure 4 This is a schematic diagram of the spot size calibration principle of the spectral confocal displacement sensor.

[0038] Explanation of the numbers in the figure: 1. Laser interferometer, 2. Laser feedback module, 3. First electric motion stage, 4. Second electric motion stage, 5. Probe horizontal angle adjustment stage, 6. Extreme angle calibration stage, 7. Calibration checkerboard, 8. Linear calibration mirror, 9. Probe fixing stage, 10. Spectral confocal probe, 11. Spectral confocal controller, 12. Host computer, 13. Measurement beam, 14. Reflected beam. DETAILED DESCRIPTION

[0039] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0040] like Figure 1 and Figure 2 As shown, a multifunctional automatic calibration device for a spectral confocal displacement sensor includes:

[0041] A laser interferometer 1, wherein a laser feedback module 2 is provided on the emission light path of the laser interferometer 1 so that the laser emitted by the laser interferometer 1 is returned by the laser feedback module 2 for measuring the position of the laser feedback module 2;

[0042] The laser feedback module 2 is arranged on the first electric motion stage 3 and is controlled to move by the first electric motion stage 3. A linear calibration mirror 8 is provided on the first electric motion stage 3, and the first electric motion stage 3 controls the linear calibration mirror 8 to move synchronously with the laser feedback module 2, so that the positions of the laser feedback module 2 and the linear calibration mirror 8 are relatively fixed. Therefore, the displacement of the laser feedback module 2 measured by the laser interferometer 1 can also be regarded as the displacement of the linear calibration mirror 8;

[0043] The linear calibration reflector 8 reflects the white light emitted by the spectral confocal probe 10 to characterize the displacement measurement value of the spectral confocal probe 10 and achieve comparison with the displacement measurement value of the laser interferometer 1;

[0044] A second electric motion platform 4 is provided on one side of the first electric motion platform 3 and is perpendicular to the first electric motion platform 3. A probe horizontal angle adjustment platform 5 is provided on the second electric motion platform 4 for movement control.

[0045] The spectral confocal probe 10:

[0046] It is installed on the probe horizontal angle adjustment platform 5 and is controlled by the probe horizontal angle adjustment platform 5 for rotation, and is used for extreme angle measurement and spot size measurement;

[0047] Alternatively, it may be placed on the probe fixing platform 9 for linear calibration.

[0048] The outer side of the probe horizontal angle adjustment platform 5 is provided with a limit angle calibration platform 6. When measuring the limit angle, the probe horizontal angle adjustment platform 5 is used to adjust the light outlet of the spectral confocal probe 10 to align with the limit angle calibration platform 6. In this embodiment, Figure 3 As shown, when the extreme angle calibration platform 6 is in the initial position, it is perpendicular to the measuring beam 14 emitted by the spectral confocal probe 10, and the measuring beam 13 emitted by the spectral confocal probe 10 is reflected by the extreme angle calibration platform 6 and returns along the original path; when the extreme angle calibration platform 6 is in the tilted position, the measuring beam 13 emitted by the spectral confocal probe 10 is reflected by the extreme angle calibration platform and no longer returns along the original path, and the reflected beam 14 returns at a certain angle to the original beam. When the reflected beam is within the receiving range of the spectral confocal probe 10, measurement can still be performed at this time; when the tilt angle continues to increase, there will be an angle When the angle is greater than this, the reflected light beam 14 will exceed the receiving range of the spectral confocal probe 10. This is the probe's measurement limit angle.

[0049] A calibration checkerboard 7 is provided on the inner side of the probe horizontal angle adjustment platform 5, and the calibration checkerboard 7 is controlled by the first electric motion platform 3 to move in a direction perpendicular to the second electric motion platform 4. After the limit angle measurement is completed, the probe horizontal angle adjustment platform 5 controls the spectral confocal probe 10 to rotate 180 degrees so that its light outlet is aligned with the calibration checkerboard 7, so that the calibration checkerboard 7 can return the measurement beam 13 of the spectral confocal probe 10 to perform spot size measurement. The spot size measurement is achieved by the stepping movement of the calibration checkerboard 7. The spot size measurement can be measured in two perpendicular directions. In this embodiment, Figure 4As shown, the calibration checkerboard 7 is controlled by the first electric motion stage 3 to move in a direction perpendicular to the optical axis of the spectral confocal probe 10. The host computer 12 sends an instruction to the spectral confocal controller 11 to read the light intensity. The calibration checkerboard 7 is composed of black and white squares. The spectral confocal probe 10 measures the light beam. The light intensity reflected by the squares of different colors on the calibration checkerboard 7 is different. According to the jump of light intensity at the junction of black and white squares, the calibration of the spot size can be achieved.

[0050] The probe fixing platform 9 is arranged at the outer end of the first electric motion platform 3, so that the laser interferometer 1, laser feedback module 2, linear calibration mirror 8, and spectral confocal probe 10 are located on the same straight line, and the measuring beam of the laser interferometer 1 is collinear with the measuring beam 13 of the spectral confocal probe 10, which is used for linear calibration. When performing linear error calibration, the first electric motion platform 3 controls the linear calibration mirror 8 to move over a large range along the collinear direction of the laser interferometer 1 and the spectral confocal probe 10. When performing spot size calibration, the first electric motion platform 3 controls the calibration checkerboard 7 to move over a small range in a direction perpendicular to the second electric motion platform 4, so that the calibration checkerboard 7 can return to the measuring beam 13 of the spectral confocal probe 10. The second electric motion platform 4 can control the movement of the spectral confocal probe 10 so that the calibration checkerboard 7 is within the measuring range of the spectral confocal probe 10.

[0051] The extreme angle calibration platform 6 is rotatably disposed on a corresponding frame, so that the angle of the extreme angle calibration platform 6 relative to the spectral confocal probe 10 is adjustable.

[0052] The probe fixing platform 9 clamps the spectral confocal probe 10 through the V-shaped groove provided thereon. The opening width, opening angle and fixing position of the V-shaped groove can be freely adjusted to accommodate spectral confocal probes 10 of different lengths and diameters.

[0053] The spectral confocal probe 10 is communicatively connected to the spectral confocal controller 11 via an optical fiber, and the spectral confocal controller 11 is network-communicated with the host computer 12 for data acquisition. The host computer 12 is respectively connected to the first electric motion stage 3, the second electric motion stage 4, the probe horizontal angle adjustment stage 5, the extreme angle calibration stage 6 and the laser interferometer 1 for controlling the corresponding actions for posture adjustment, wherein the first electric motion stage 3 and the second electric motion stage 4 can be controlled by the host computer 12 to perform linear motion, and the probe horizontal angle adjustment stage 5 and the extreme angle calibration stage 6 can be controlled by the host computer 12 to rotate.

[0054] A detection method using a multifunctional automated calibration device for a spectral confocal displacement sensor, the method comprising limit angle measurement and spot size measurement, wherein:

[0055] The limit angle measurement method is as follows: when the optical axis of the spectral confocal probe 10 is not perpendicular to the limit angle calibration platform 6, the maximum angle that the limit angle calibration platform 6 can rotate relative to the vertical position is the limit angle, the host computer 12 controls the rotation of the limit angle calibration platform 6, and at the same time sends an instruction to the spectral confocal controller 11 to read the displacement measurement data. When the measurement data of the spectral confocal controller 11 jumps to an invalid value, the host computer 12 reads the angle of the limit angle calibration platform 6 ,angle This is the limit measurement angle of the spectral confocal probe 10;

[0056] The spot size measurement method is as follows: a calibration checkerboard 7 is controlled by a first electric motion stage 3 to move in a direction perpendicular to the optical axis of a spectral confocal probe 10, and a command is sent to a spectral confocal controller 11 via a host computer 12 to read the light intensity. The calibration checkerboard 7 is composed of black and white squares. The measurement beam 13 of the spectral confocal probe 10 reflects different light intensities on squares of different colors on the calibration checkerboard 7. The spot size measurement and calibration are achieved based on the jump in light intensity at the junction of black and white squares.

[0057] The method also includes linear calibration, and the linear calibration method is:

[0058] First, the spectral confocal probe 10 is fixed on the probe fixing platform 9 so that the measuring beam 13 of the spectral confocal probe 10 is collinear with the measuring beam of the laser interferometer 1. The first electric motion platform 3 controls the linear calibration mirror 8 to move along the measuring beam 13 of the spectral confocal probe 10. The peak positioning algorithm is used as the positioning criterion to determine whether a valid measurement peak value is detected, and the spectral confocal probe 10 is positioned at the near end and the far end of the measuring range.

[0059] After locating the near end and far end of the range of the spectral confocal probe 10, the midpoint of the far end and the near end is used as the zero point, and the measurement values of the laser interferometer 1 and the spectral confocal probe 10 are reset to zero. Then, the linear calibration mirror 8 is controlled by the first electric motion stage 3 to move to the near end of the range of the spectral confocal probe 10. The step distance of the first electric motion stage 3 is set to d, the movement speed is set to v, and the actual range of the spectral confocal probe 10 is taken as D. Then, n = D / d measurement positions are sampled within the full range of the probe during the scanning process;

[0060] The host computer 12 controls the first electric motion stage 3 to move stepwise from the near end of the measuring range to the far end of the measuring range. Each time it steps to a measuring point, the host computer 12 samples the spectral confocal controller 11 and the laser interferometer 1 and saves the samples to the host computer 12.

[0061] After the full-range scan is completed, the displacement measurement deviations of the spectral confocal probe 10 and the laser interferometer 1 at n sampling points are obtained.

[0062] After obtaining the displacement measurement values of the spectral confocal probe 10 and the laser interferometer 1 at all sampling points, a nonlinear relationship between the displacement measurement values of the spectral confocal probe 10 and the displacement measurement values of the laser interferometer 1 is obtained by spline curve fitting. Then, equal-interval sampling is performed between the near end and the far end of the measuring range of the spectral confocal probe 10. A mapping calibration table between the displacement measurement values of the spectral confocal probe 10 and the displacement measurement values of the laser interferometer 1 is generated by the nonlinear relationship. The mapping calibration table is uploaded to the spectral confocal controller 11, thereby greatly improving the measurement accuracy of the spectral confocal displacement sensor.

[0063] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A multifunctional automated calibration device for spectral confocal displacement sensors, characterized in that: include: A laser interferometer (1), wherein a laser feedback module (2) is provided on an emission light path of the laser interferometer (1), so that laser light emitted by the laser interferometer (1) is returned by the laser feedback module (2) for measuring the position of the laser feedback module (2); The laser feedback module (2) is arranged on a first electric motion platform (3) and is controlled to move by the first electric motion platform (3); a linear calibration reflector (8) is provided on the first electric motion platform (3), and the first electric motion platform (3) controls the linear calibration reflector (8) to move synchronously with the laser feedback module (2), so that the positions of the laser feedback module (2) and the linear calibration reflector (8) are relatively fixed; The linear calibration reflector (8) reflects white light emitted by the spectral confocal probe (10) to characterize the displacement measurement value of the spectral confocal probe (10) and achieve comparison with the displacement measurement value of the laser interferometer (1); A second electric motion platform (4) perpendicular to the first electric motion platform (3) is provided on one side of the first electric motion platform (3); a probe horizontal angle adjustment platform (5) is provided on the second electric motion platform (4) for movement control; The spectral confocal probe (10): It is arranged on the probe horizontal angle adjustment platform (5) and is controlled to rotate by the probe horizontal angle adjustment platform (5), and is used for extreme angle measurement and spot size measurement; or set on a probe fixing table (9) for linear calibration; The outer side of the probe horizontal angle adjustment platform (5) is provided with a limit angle calibration platform (6), and when the limit angle is measured, the probe horizontal angle adjustment platform (5) adjusts the light outlet of the spectral confocal probe (10) to align with the limit angle calibration platform (6), and the inner side of the probe horizontal angle adjustment platform (5) is provided with a calibration checkerboard (7), and the calibration checkerboard (7) is controlled by the first electric motion platform (3) to move in a direction perpendicular to the second electric motion platform (4), and is used for after the limit angle measurement is completed, the probe horizontal angle adjustment platform (5) controls the spectral confocal probe (10) to rotate 180 degrees so that the light outlet is aligned with the calibration checkerboard (7), so that the calibration checkerboard (7) can return the measurement light beam (13) of the spectral confocal probe (10) to perform spot size measurement; The probe fixing platform (9) is arranged at the outer end of the first electric motion platform (3), so that the laser interferometer (1), the laser feedback module (2), the linear calibration reflector (8), and the spectral confocal probe (10) are located on the same straight line, and the measuring beam of the laser interferometer (1) and the measuring beam (13) of the spectral confocal probe (10) are collinear, for linear calibration.

2. The automatic multifunctional calibration device for spectral confocal displacement sensors according to claim 1, characterized in that: The extreme angle calibration platform (6) is rotatably arranged on a corresponding frame, so that the angle of the extreme angle calibration platform (6) relative to the spectral confocal probe (10) is adjustable.

3. The automatic multifunctional calibration device for spectral confocal displacement sensors according to claim 1, characterized in that: The probe fixing platform (9) clamps the spectral confocal probe (10) via a V-shaped groove provided thereon, so as to be suitable for spectral confocal probes (10) of different lengths and diameters.

4. The automatic multifunctional calibration device for spectral confocal displacement sensors according to claim 1, characterized in that: The spectral confocal probe (10) is communicatively connected to the spectral confocal controller (11) via an optical fiber, and the spectral confocal controller (11) is communicatively connected to a host computer (12) via a network for data acquisition. The host computer (12) is respectively connected to the first electric motion stage (3), the second electric motion stage (4), the probe horizontal angle adjustment stage (5), the extreme angle calibration stage (6) and the laser interferometer (1) for controlling corresponding actions to adjust the posture.

5. A detection method using the spectral confocal displacement sensor automatic multifunctional calibration device according to any one of claims 1 to 4, characterized in that: The method includes a limit angle measurement method and a spot size measurement method, wherein: The limit angle measurement method is as follows: when the optical axis of the spectral confocal probe (10) is set to be non-vertical to the limit angle calibration platform (6), the maximum angle at which the limit angle calibration platform (6) can rotate relative to the vertical position is the limit angle, the host computer (12) controls the rotation of the limit angle calibration platform (6), and simultaneously sends an instruction to the spectral confocal controller (11) to read the displacement measurement data, and when the measurement data of the spectral confocal controller (11) jumps to an invalid value, the host computer (12) reads the angle θ1 of the limit angle calibration platform (6), and the angle θ1 is the limit measurement angle of the spectral confocal probe (10); The spot size measurement method is as follows: a calibration checkerboard (7) is controlled by a first electric motion stage (3) to move in a direction perpendicular to the optical axis of a spectral confocal probe (10), and a command is sent to a spectral confocal controller (11) via a host computer (12) to read the light intensity. The calibration checkerboard (7) is composed of black and white squares. The measurement light beam (13) of the spectral confocal probe (10) reflects different light intensities on squares of different colors on the calibration checkerboard (7). The measurement calibration of the spot size is achieved based on the jump of light intensity at the junction of black and white squares.

6. The detection method according to claim 5, characterized in that The detection method also includes a linear calibration method, which is: First, a spectral confocal probe (10) is fixed on a probe fixing platform (9) so that a measuring beam (13) of the spectral confocal probe (10) is collinear with a measuring beam of a laser interferometer (1). A first electric motion platform (3) controls a linear calibration reflector (8) to move along the direction of the measuring beam (13) of the spectral confocal probe (10). Whether a peak positioning algorithm detects an effective measurement peak is used as a positioning criterion, and the spectral confocal probe (10) is positioned at the near end and the far end of the measuring range respectively. After locating the near end and the far end of the range of the spectral confocal probe (10), the midpoint of the far end and the near end is used as the zero point, and the measurement values of the laser interferometer (1) and the spectral confocal probe (10) are reset to zero. Then, the linear calibration reflector (8) is controlled by the first electric motion stage (3) to move to the near end of the range of the spectral confocal probe (10). The step distance of the first electric motion stage (3) is set to d, the movement speed is set to v, and the actual range of the spectral confocal probe (10) is taken as D. Then, n=D / d measurement positions are sampled within the full range of the probe during the scanning process, and n is the number of sampling points. The host computer (12) controls the first electric motion stage (3) to move stepwise from the near end of the measuring range to the far end of the measuring range. Each time it steps to a measuring point, the host computer (12) samples the spectral confocal controller (11) and the laser interferometer (1) and stores the samples in the host computer (12); After the full-range scan is completed, the displacement measurement deviations of the spectral confocal probe (10) and the laser interferometer (1) at n sampling points are obtained.

7. The detection method according to claim 6, characterized in that After obtaining the displacement measurement values of the spectral confocal probe (10) and the laser interferometer (1) at all sampling points, a nonlinear relationship between the displacement measurement values of the spectral confocal probe (10) and the displacement measurement values of the laser interferometer (1) is obtained by spline curve fitting, and then equally spaced sampling is performed between the near end and the far end of the range of the spectral confocal probe (10). A mapping calibration table between the displacement measurement values of the spectral confocal probe (10) and the displacement measurement values of the laser interferometer (1) is generated by the nonlinear relationship, and the mapping calibration table is uploaded to the spectral confocal controller (11), thereby greatly improving the measurement accuracy of the spectral confocal displacement sensor.

Images