Non-contact laser micro-nano measurement dynamic adjusting system and method

Abstract

The invention discloses a non-contact laser micro-nano measurement dynamic adjustment system and method, and relates to the technical field of laser micro-nano measurement, and the method comprises the steps: importing a fixed motion track parameter of a to-be-measured object, generating a motor pre-judgment motion instruction, driving a motor to operate synchronously, locking a to-be-measured region, and recording a motor motion track parameter; emitting laser beams to irradiate the to-be-measured area after being processed, and recording initial light path parameters; detecting a reflected light signal through an illuminance sensor; when the effective reflected light is not captured, a light reflection path model is constructed based on the motor movement track parameters and the initial light path parameters, the motor displacement compensation amount is obtained through calculation, and the relative position of the to-be-detected area and the light path is adjusted according to the motor displacement compensation amount until the effective reflected light is captured; reflected light measurement data are collected and converted into digital signals, and depth data and width data of the sample are obtained through fitting processing of a point cloud algorithm and resolving.

Description

Technical Field

[0001] This invention relates to the field of laser micro-nano measurement technology, specifically a non-contact laser micro-nano measurement dynamic adjustment system and method. Background Technology

[0002] In the field of laser micro-nano manufacturing, accurate measurement of sample surface morphology is the core prerequisite for ensuring processing accuracy and forming quality. However, its measurement requirements place demands on the dynamic adaptability, compensation accuracy, and solution reliability of the technology. Existing technologies have many key shortcomings and are difficult to meet the needs of practical applications.

[0003] Existing technologies do not consider the dynamic characteristics of the object under test. Measurement and positioning are often designed for static or simple motion scenarios, failing to incorporate fixed motion trajectory parameters of the object. This makes it impossible to predict the position of the dynamic measurement area in advance, relying solely on passive adjustments based on real-time position feedback, resulting in lagging dynamic positioning and low accuracy. Traditional methods do not consider situations where reflected light does not reach the illuminance sensor. When reflected light deviates from the sensor due to optical path offset, component obstruction, or changes in sample morphology, the lack of a correlation model between the motor's motion trajectory and optical path parameters makes it impossible to quantify the required displacement compensation for the motor. This necessitates reliance on manual experience or blind adjustments, leading to low efficiency and the introduction of new errors, severely impacting measurement continuity. Furthermore, existing technologies lack a precise calculation link from measurement data to sample depth and width data. The absence of standardized digital signal conversion, point cloud processing, and fitting solutions makes it impossible to reliably output sample depth and width data, hindering the accurate planning of subsequent processing paths. Summary of the Invention

[0004] The purpose of this invention is to provide a non-contact laser micro / nano measurement dynamic adjustment system and method to solve the problems raised in the prior art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, the present invention provides a non-contact laser micro / nano measurement dynamic adjustment method, comprising: Import the fixed motion trajectory parameters of the object under test, generate motor prediction motion commands, and drive the motor to run synchronously; adjust the motor position through closed loop, lock the test area of ​​the object under test, and record the motor motion trajectory parameters; A laser beam is emitted, processed, and then irradiated onto the locked area to be measured, and the initial optical path parameters are recorded. The reflected light signal is detected in real time by a light intensity sensor to obtain the capture result of the effective reflected light. When no effective reflected light is captured, a light reflection path model is constructed based on the motor motion trajectory parameters and the initial optical path parameters; Based on the light reflection path model, the motor displacement compensation amount is obtained by calculation; based on the motor displacement compensation amount, the relative position of the area to be measured and the light path is adjusted until the illuminance sensor captures the effective reflected light, and the measurement data is acquired and converted into a digital signal. Based on the obtained digital signal, the depth and width data of the sample are calculated by fitting the point cloud algorithm.

[0006] In conjunction with the first aspect, in the first implementation of the first aspect of this application, the step of importing the fixed motion trajectory parameters of the object to be tested, generating a motor prediction motion command, and driving the motor to run synchronously includes: The system acquires and imports fixed motion trajectory parameters of the object under test, including dynamic motion trajectory equations, relative position coordinates of the test area, and motion velocity curves of the X, Y, and Z axes. It then uses a cubic spline interpolation trajectory analysis algorithm to calculate the predicted dynamic center coordinates of the test area at each moment in real time. Based on these predicted dynamic center coordinates, it plans the running speeds of the X, Y, and Z axis motors and generates predicted motor motion commands, including dynamic running speeds of each axis, real-time target tracking coordinates, and preset displacements for each axis. Finally, it drives the X, Y, and Z axis motors to run synchronously according to these predicted motion commands.

[0007] In conjunction with the first aspect, in the second implementation of the first aspect of this application, the step of locking the test area of ​​the object under test by adjusting the motor position through closed loop and recording the motor motion trajectory parameters includes: The actual position of each axis is collected in real time by the position sensor integrated in the motor, and the measured dynamic center coordinates of the current test area are obtained by conversion. The measured dynamic center coordinates of the test area are compared with the predicted dynamic center coordinates of the test area to obtain the position deviation value. When the position deviation value exceeds the preset positioning deviation threshold, the motor position is corrected in real time by the PID closed-loop adjustment algorithm. When the position deviation value is less than or equal to the preset positioning deviation threshold, the test area is determined to be locked. The motor motion trajectory parameters are recorded, including the actual displacement of the X, Y, and Z axes, the measured dynamic center coordinates of the test area, and the synchronization error of each axis displacement. The synchronization error of each axis displacement is the absolute value of the difference between the actual displacement of each axis and the preset displacement of each axis.

[0008] In conjunction with the first aspect, in the third implementation of the first aspect of this application, the emitted laser beam, after processing, illuminates the locked test area, and the initial optical path parameters are recorded, including: A laser beam is emitted from a laser and sequentially expanded and collimated by a beam expander, reflected and redirected by a cubic beam splitter, focused by a high-magnification objective, and suppressed by an aperture to suppress non-focal scattered light, thus completing beam processing. The processed laser beam is then guided to the locked test area to measure the dynamic center coordinates. The initial core optical path parameters are recorded, including the beam propagation direction after beam processing, the optimized optical path parameters of the beam expander, the reflection angle parameters of the cubic beam splitter, the focusing configuration parameters of the high-magnification objective, and the aperture parameters.

[0009] In conjunction with the first aspect, in the fourth implementation of the first aspect of this application, the step of obtaining the effective reflected light capture result by real-time detection of the reflected light signal through an illuminance sensor includes: The reflected light signal of the area under test is captured in real time by a light intensity sensor. When the peak value of the reflected light intensity signal detected by the light intensity sensor is greater than the preset effective light intensity threshold and the duration is greater than the preset effective time threshold, it is determined that effective reflected light has been captured. When at least one condition is not met, it is determined that effective reflected light has not been captured.

[0010] In conjunction with the first aspect, in the fifth implementation of the first aspect of this application, the step of constructing a light reflection path model based on the motor motion trajectory parameters and the initial optical path parameters when no effective reflected light is captured includes: When it is determined that no effective reflected light has been captured, the motor motion trajectory parameters and initial optical path parameters are used as input parameters for the light reflection path model. A three-dimensional rectangular coordinate system is established with the measured dynamic center coordinates of the area under test as the origin. The three-dimensional coordinates of the beam expander, cubic beam splitter, high-magnification objective, and aperture are calculated and mapped to the three-dimensional rectangular coordinate system based on the physical installation spacing of each optical element and the initial optical path parameters. Based on the core parameters of the initial optical path, the transformation parameters of each optical element are obtained. Specifically, the beam expander optical path optimization parameters are transformed into beam divergence angle correction coefficients, the cubic beam splitter reflection angle parameters are transformed into three-dimensional coordinates of the normal vector of the reflecting surface, the high-magnification objective focusing configuration parameters are transformed into focal length and numerical aperture, and the aperture parameters are transformed into light transmission range. The synchronous error of each axis displacement is transformed into the coordinate offset of the area under test, superimposed on the measured dynamic center coordinates of the area under test to obtain the actual incident point coordinates. The least squares method is used to fit the surface contour plane equation of the area under test and solve for the normal vector at the actual incident point. Starting from the coordinates of the laser emission point, an initial incident ray direction vector is generated by combining the beam propagation direction and the beam divergence angle correction coefficient. The initial incident ray direction vector is then adjusted by substituting the transformation parameters of each optical element to obtain the incident ray straight line equation. The actual incident point coordinates are then substituted into the incident ray straight line equation to correct and obtain the final incident ray direction vector. Based on the reflection law formula, the reflected ray direction vector is calculated by combining the final incident ray direction vector and the normal vector at the actual incident point. The reflected ray straight line equation is then generated based on the reflected ray direction vector. The light reflection path model is constructed by calling parameters, setting up a coordinate system, transforming parameters, and calculating the trajectories of incident and reflected rays.

[0011] In conjunction with the first aspect, in the sixth implementation of the first aspect of this application, the step of calculating the motor displacement compensation amount based on the light reflection path model includes: The effective geometric parameters of the existing illuminance sensor receiving surface are extracted, including the plane equation and effective boundary coordinates of the receiving surface. The equation of the reflected ray line output from the constructed light reflection path model is combined with the plane equation of the receiving surface to calculate the theoretical landing point coordinates of the reflected ray. By comparing the theoretical landing point coordinates with the effective boundary coordinates of the receiving surface, the deviation direction and deviation distance of the reflected ray that did not fall on the illuminance sensor receiving surface are obtained. Based on the trajectory calculation logic of the incident ray and the reflected ray in the light reflection path model, the laser incident angle correction amount and laser focal point position correction amount required to eliminate the deviation are derived in reverse according to the deviation direction and deviation distance. The laser incident angle correction amount and laser focal point position correction amount are converted into the displacement adjustment requirements of the X, Y, and Z axis motors as motor displacement compensation amounts, including the compensation direction and compensation amount values ​​of each axis motor.

[0012] In conjunction with the first aspect, in the seventh implementation of the first aspect of this application, the step of adjusting the relative position of the area to be measured and the optical path based on the motor displacement compensation amount until the illuminance sensor captures effective reflected light, acquiring measurement data and converting it into a digital signal includes: Based on the motor displacement compensation, a motor linkage control command is generated to drive the X, Y, and Z axis motors to adjust the relative position of the area under test and the optical path, thereby changing the incident angle of the laser beam. During the motor's adjustment action, the reflected light signal of the area under test is continuously captured by the illuminance sensor. When effective reflected light is captured, the reflected light measurement data of the current optical path is obtained, including the reflected light intensity distribution, optical path difference, and reflected light phase information. The acquired reflected light measurement data is converted into a digital signal, filtered and denoised, and then stored.

[0013] In conjunction with the first aspect, in the eighth implementation of the first aspect of this application, the step of calculating the depth and width data of the sample by fitting the obtained digital signal using a point cloud algorithm includes: The stored digital signal is converted into three-dimensional spatial point cloud data. Specifically, the Z-axis coordinates of each measurement point are calculated using the reflected light phase information and optical path difference quantization data, and the X and Y-axis coordinates of each measurement point are calculated using the reflected light intensity distribution quantization data combined with the laser beam scanning trajectory, thus forming a three-dimensional point cloud dataset. The 3D point cloud dataset is preprocessed by sequentially performing point cloud deduplication, statistical filtering, and data downsampling to obtain preprocessed point cloud data. A point cloud fitting algorithm is then used to process the preprocessed point cloud data to calculate sample depth and width data. Specifically, to calculate sample depth, the point cloud data of the sample's test area is selected, and the 3D surface equation of the sample surface is obtained through least squares fitting. Using the XY plane of the 3D Cartesian coordinate system as a preset reference plane, the Z-axis distance between each point on the surface equation and the reference plane is calculated to represent the sample depth data at the corresponding location. The maximum, minimum, and gradient values ​​of the sample depth data are extracted to form complete depth information. To calculate sample width, the projection point set of the 3D point cloud data onto the preset reference plane is extracted. The Canny edge detection algorithm is used to identify the boundary contour of the projection point set, and the equation of the closed curve of the boundary contour is obtained through polynomial fitting. The maximum distance of the closed curve in the preset measurement direction is calculated to represent the width data of the sample in the corresponding direction. The sample depth and width data are then integrated and output.

[0014] Secondly, the present invention provides a non-contact laser micro / nano measurement dynamic adjustment system, comprising: Optical module, measurement module, control module, dynamic adjustment module, and point cloud computing module; The optical module is used to adjust the beam and focus it onto the surface of the sample to be tested. It includes a laser, a cubic beam splitter, a high-power objective lens, and an aperture. The laser emits a beam, which is expanded and collimated by a beam expander to optimize the beam characteristics. The beam is reflected by the cubic beam splitter, and the reflected beam is focused by the high-power objective lens. The aperture suppresses non-focal scattered light and guides the beam to the test area of ​​the sample. The measurement module is used to acquire measurement data related to reflected light, including an illuminance sensor; after the light beam is irradiated onto the sample by the optical module, the reflected light from the sample surface is captured by the illuminance sensor to obtain measurement data; The control module is used to control the system's start and stop, receive measurement data, and convert analog and digital signals. It includes a core control unit, a sensor unit, and a digital-to-analog converter module. The core control unit starts the equipment, receives the measurement data transmitted by the measurement module through the sensor unit, and converts the analog measurement data into digital signals through the digital-to-analog converter module. The dynamic adjustment module is used to receive the motor displacement compensation amount from the control module, generate X, Y, and Z axis motor control commands, drive the motor to run, collect the actual position of the motor through the position sensor and feed it back, and correct the deviation through PID closed-loop adjustment until the illuminance sensor captures the effective reflected light, thereby realizing the dynamic positioning of the area to be measured. The point cloud computing module is used to calculate the depth and width data of the sample micro-nano structure in real time. It receives digital signals from the control module and obtains the sample depth and width data through point cloud algorithm fitting.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention imports fixed motion trajectory parameters of the object to be tested and adjusts the motor to achieve locking of the dynamic test area.

[0016] 2. The present invention solves the problem of calculating the motor displacement compensation amount that needs to be adjusted when the reflected light does not reach the illuminance sensor, so that the adjusted reflected light can be collected by the illuminance sensor.

[0017] 3. This invention obtains measurement data through a light intensity sensor, converts it into digital signals, and calculates the depth and width data of the sample. Attached Figure Description

[0018] Figure 1 This is a schematic diagram illustrating the steps of a non-contact laser micro / nano measurement dynamic adjustment method according to the present invention. Figure 2 This is a flowchart of a non-contact laser micro / nano measurement dynamic adjustment method according to the present invention. Figure 3 This is a system structure diagram of a non-contact laser micro / nano measurement dynamic adjustment system according to the present invention. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Example: Figures 1-3 As shown, the present invention provides a technical solution. like Figure 1 A schematic diagram illustrating the steps of a non-contact laser micro / nano measurement dynamic adjustment method is shown. This invention provides a non-contact laser micro / nano measurement dynamic adjustment method, comprising: Step S100: Import the fixed motion trajectory parameters of the object under test, generate the motor prediction motion command, and drive the motor to run synchronously; adjust the motor position through closed loop, lock the test area of ​​the object under test, and record the motor motion trajectory parameters; Specifically, the fixed motion trajectory parameters of the object under test are acquired and imported, including the dynamic motion trajectory equation, the relative position coordinates of the area under test, and the motion velocity curves of the X, Y, and Z axes. The predicted dynamic center coordinates of the area under test at each moment are obtained in real time through a cubic spline interpolation trajectory analysis algorithm. Based on the predicted dynamic center coordinates of the area under test, the running speeds of the X, Y, and Z axis motors are planned, and the predicted motion commands of the motors are generated, including the dynamic running speed of each axis, the real-time target tracking coordinates, and the preset displacement of each axis. The preset displacement of each axis is generated by integrating the real-time target tracking coordinates. The X, Y, and Z axis motors are driven to run synchronously according to the predicted motion commands of the motors.

[0021] The actual position of each axis is collected in real time by the position sensor integrated in the motor, and the measured dynamic center coordinates of the current test area are obtained by conversion. The measured dynamic center coordinates of the test area are compared with the predicted dynamic center coordinates of the test area to obtain the position deviation value. When the position deviation value exceeds the preset positioning deviation threshold, the motor position is corrected in real time by a PID closed-loop adjustment algorithm. The specific values ​​of the PID parameters are determined by debugging according to the motor model. When the position deviation value is less than or equal to the preset positioning deviation threshold, the test area is considered to be locked. The motor motion trajectory parameters are recorded, including the actual displacement of the X, Y, and Z axes, the measured dynamic center coordinates of the test area, and the synchronization error of each axis displacement. The synchronization error of each axis displacement is the absolute value of the difference between the actual displacement of each axis and the preset displacement of each axis.

[0022] Step S200: Emit a laser beam, process it, and then illuminate the locked test area, recording the initial optical path parameters; use an illuminance sensor to detect the reflected light signal in real time to obtain the effective reflected light capture result; Specifically, a laser beam is emitted from a laser and sequentially expanded and collimated by a beam expander, reflected and redirected by a cubic beam splitter, focused by a high-magnification objective, and suppressed by an aperture to suppress non-focal scattered light, thus completing beam processing. The processed laser beam is then guided to the locked test area to measure the dynamic center coordinates. The initial core optical path parameters are recorded, including the beam propagation direction after beam processing, the optimized optical path parameters of the beam expander, the reflection angle parameters of the cubic beam splitter, the focusing configuration parameters of the high-magnification objective, and the aperture parameters.

[0023] The reflected light signal of the area under test is captured in real time by a light intensity sensor. When the peak value of the reflected light intensity signal detected by the light intensity sensor is greater than the preset effective light intensity threshold and the duration is greater than the preset effective time threshold, it is determined that effective reflected light has been captured. When at least one condition is not met, it is determined that effective reflected light has not been captured.

[0024] Step S300: When no effective reflected light is captured, construct a light reflection path model based on the motor motion trajectory parameters and the initial optical path parameters; Specifically, when it is determined that no effective reflected light has been captured, the motor motion trajectory parameters and initial optical path parameters are used as input parameters for the light reflection path model. A three-dimensional rectangular coordinate system is established with the measured dynamic center coordinates of the area under test as the origin. The three-dimensional coordinates of the beam expander, cubic beam splitter, high-magnification objective lens, and aperture are calculated and mapped to the three-dimensional rectangular coordinate system based on the physical installation spacing of each optical element and the initial optical path parameters. Based on the core parameters of the initial optical path, the transformation parameters of each optical element are obtained. Specifically, the beam expander optical path optimization parameters are transformed into the beam divergence angle correction coefficient θ. The transformation formula is as follows: ; Where n is the refractive index of the beam expander lens, and β is the beam expansion ratio in the optical path optimization parameters; The reflection angle parameter α of the cubic beam splitter is transformed into the three-dimensional coordinates of the reflection surface normal vector based on the geometric relationship between the reflection surface normal vector and the reflection angle: ; Extract the focal length and numerical aperture from the focusing configuration parameters of the high-magnification objective lens, and use the aperture parameter as the light transmission range; The synchronous error ΔS of displacement along each axis is converted into the coordinate offset ΔP of the area to be measured, using the following formula: ; Where k is a known transmission ratio, determined by the selection of the transmission mechanism; ΔP is superimposed onto the measured dynamic center coordinates of the area to be measured to obtain the actual incident point coordinates. The least squares method is used to fit the surface contour plane equation of the area to be measured, and the normal vector at the actual incident point is solved by the gradient of the plane equation. Starting from the coordinates of the laser emission point, an initial incident ray direction vector is generated by combining the beam propagation direction and beam divergence angle correction coefficient. The initial incident ray direction vector is then adjusted by substituting the transformation parameters of each optical element to obtain the incident ray line equation. The actual incident point coordinates are then substituted into the incident ray line equation to correct and obtain the final incident ray direction vector. Finally, based on the reflection law formula and the final incident ray direction vector… and the normal vector at the actual incident point The direction vector of the reflected ray is calculated. The formula is: ; Generate the equation of the straight line of the reflected ray based on the direction vector of the reflected ray; The light reflection path model is constructed by calling parameters, setting up a coordinate system, transforming parameters, and calculating the trajectories of incident and reflected rays.

[0025] Step S400: Based on the light reflection path model, the motor displacement compensation amount is calculated; based on the motor displacement compensation amount, the relative position of the area to be measured and the light path is adjusted until the illuminance sensor captures the effective reflected light, the measurement data is acquired and converted into a digital signal; Specifically, the effective geometric parameters of the existing light intensity sensor receiving surface are extracted as the sensor's factory calibration parameters, including the plane equation and effective boundary coordinates of the receiving surface. The linear equation of the reflected ray output from the constructed light reflection path model is combined with the plane equation of the receiving surface to calculate the theoretical landing point coordinates of the reflected ray. By comparing the theoretical landing point coordinates with the effective boundary coordinates of the receiving surface, the deviation direction and deviation distance of the reflected ray not landing on the light intensity sensor receiving surface are obtained. Specifically, this is calculated using the coordinate difference method, where the deviation direction is determined along the positive and negative directions of the coordinate axes in a three-dimensional rectangular coordinate system, and the deviation distance is the Euclidean distance between the theoretical landing point coordinates and the effective boundary coordinates of the receiving surface. Based on the trajectory calculation logic of the incident and reflected rays in the light reflection path model, the laser incident angle correction amount Δθ required to eliminate the deviation is derived in reverse from the deviation direction and deviation distance. x , Δθ y And the laser focal point position correction amount Δz; convert the laser incident angle correction amount and the laser focal point position correction amount into the displacement adjustment requirements of the X, Y, and Z axis motors, as the motor displacement compensation amount, including the compensation direction and compensation amount value of each axis motor. The conversion formula is: ; ; ; Where ΔX, ΔY and ΔZ are the displacement adjustment requirements of the X, Y and Z axis motors, respectively, and L is the working distance in the focusing configuration parameters of the high-magnification objective lens; Based on the motor displacement compensation, a motor linkage control command is generated to drive the X, Y, and Z axis motors to adjust the relative position of the area under test and the optical path, thereby changing the incident angle of the laser beam. During the motor's adjustment action, the reflected light signal of the area under test is continuously captured by the illuminance sensor. When effective reflected light is captured, the reflected light measurement data of the current optical path is obtained, including the reflected light intensity distribution, optical path difference, and reflected light phase information. The acquired reflected light measurement data is converted into a digital signal, filtered and denoised, and then stored.

[0026] Step S500: Based on the obtained digital signal, the depth and width data of the sample are calculated by fitting the point cloud algorithm.

[0027] Specifically, the stored digital signals are converted into three-dimensional spatial point cloud data. The Z-axis coordinates of each measurement point are calculated using the reflected light phase information and optical path difference quantization data, and the X and Y-axis coordinates of each measurement point are calculated using the reflected light intensity distribution quantization data combined with the laser beam scanning trajectory, thus forming a three-dimensional point cloud dataset. The 3D point cloud dataset is preprocessed by sequentially performing point cloud deduplication, statistical filtering, and data downsampling to obtain preprocessed point cloud data. A point cloud fitting algorithm is then used to process the preprocessed point cloud data to calculate sample depth and width data. Specifically, to calculate sample depth, the point cloud data of the sample's test area is selected, and the 3D surface equation of the sample surface is obtained through least squares fitting. Using the XY plane of the 3D Cartesian coordinate system as a preset reference plane, the Z-axis distance between each point on the surface equation and the reference plane is calculated to represent the sample depth data at the corresponding location. The maximum, minimum, and gradient values ​​of the sample depth data are extracted to form complete depth information. To calculate sample width data, the projection point set of the 3D point cloud data onto the preset reference plane is extracted. The Canny edge detection algorithm is used to identify the boundary contour of the projection point set, and the equation of the closed curve of the boundary contour is obtained through polynomial fitting. The maximum distance of the closed curve in a preset measurement direction is calculated to represent the width data of the sample in the corresponding direction. The preset measurement direction is along the two orthogonal directions of the X and Y axes of the 3D Cartesian coordinate system. The sample depth and width data are then integrated and output.

[0028] In one specific embodiment, the fixed motion trajectory parameters of the object under test are imported in step S100, and solved in real time using a cubic spline interpolation trajectory analysis algorithm. This drives the X, Y, and Z axis motors to run synchronously at a predicted speed, and the actual position is collected using position sensors. When the PID closed-loop adjustment corrects the position deviation to within 0.005mm, it is determined that the test area with coordinates (100.5, 50.2, -10.0)mm has been locked, and the motor motion trajectory parameters, including a synchronous displacement error of 0.002mm for each axis, are recorded. In step S200, the laser is activated. The light beam is collimated by a 5x beam expander, redirected by a cubic beam splitter with a 45° splitting angle, and focused by a high-magnification objective lens with a focal length of 20mm and a working distance of 20mm, guiding it to the locking area. Simultaneously, a 2mm aperture stop is used to suppress stray light. When the illuminance sensor detects a peak reflected light intensity signal of 4500 lux that persists for 30ms beyond a preset threshold, it is determined that effective reflected light has been captured. If not captured, step S300 is executed, establishing a three-dimensional rectangular coordinate system with the measured dynamic center coordinates as the origin, and superimposing the 0.002mm synchronization error of each axis displacement to convert it into actual incident light. Using the point coordinates, combined with the beam divergence angle correction coefficient and the normal vector of the reflecting surface, a light reflection path model is constructed, and the reflected light trajectory is derived in reverse. In step S400, the theoretical landing point coordinates of the reflected light on the sensor receiving surface are calculated based on the model. By comparing the effective boundary coordinates, a deviation distance of 1.5 mm is obtained. Based on this, the laser incident angle correction amount required to eliminate the deviation is calculated to be 0.05° and the focal point position correction amount is 0.1 mm. This is converted into X and Y axis motor displacement compensation of 17.5 μm and Z axis displacement compensation of 0.1 mm. A command is generated to drive the motor to adjust the relative position until the target is captured. The effective reflected light is converted into a digital signal, and the measurement data containing phase information and optical path difference is converted into a digital signal. In step S500, the digital signal is converted into three-dimensional point cloud data. After statistical filtering and downsampling preprocessing, the three-dimensional surface equation of the sample surface is obtained by fitting with the least squares method. The maximum value of the sample depth data is 1.2 mm and the minimum value is 0.1 mm. At the same time, the XY plane projection point set is extracted and the boundary closed curve is fitted using Canny edge detection. The width data of the sample in the X-axis direction is calculated to be 15.5 mm. Finally, the complete depth and width measurement results are integrated and output.

[0029] like Figure 2 The flowchart of a non-contact laser micro / nano measurement dynamic adjustment method is shown. This invention provides a non-contact laser micro / nano measurement dynamic adjustment method, comprising: The system imports the fixed motion trajectory parameters of the object under test, generates a motor prediction motion command, and drives the motor to run synchronously. It then locks the test area of ​​the object under test by adjusting the motor position through a closed-loop system and records the motor motion trajectory parameters. A laser beam is emitted, processed by the optical path, and then irradiates the locked test area, while the initial optical path parameters are recorded. A light intensity sensor detects the reflected light signal in real time to determine whether effective reflected light has been captured. When effective reflected light is detected, the system directly acquires the reflected light measurement data of the current optical path and converts it into a digital signal for storage. When effective reflected light is not detected, the system calls the motor motion trajectory parameters and the initial optical path parameters to construct a light reflection path model. Based on the light reflection path model, the system calculates the motor displacement compensation amount and adjusts the relative position of the test area and the optical path accordingly, changing the laser incident angle. During the adjustment process, the reflected light signal is continuously detected until the illuminance sensor successfully captures the effective reflected light. Once captured, the measurement data is acquired and converted into a digital signal for storage. The stored digital signal is then converted into three-dimensional point cloud data. After point cloud preprocessing and fitting algorithm processing, the depth and width data of the sample are calculated and output.

[0030] like Figure 3 The system structure diagram of a non-contact laser micro / nano measurement dynamic adjustment system is shown. This invention provides a non-contact laser micro / nano measurement dynamic adjustment system, comprising: Optical module, measurement module, control module, dynamic adjustment module, and point cloud computing module; The optical module is used to adjust the beam and focus it onto the surface of the sample to be tested. It includes a laser, a cubic beam splitter, a high-power objective lens, and an aperture. The laser emits a beam, which is expanded and collimated by a beam expander to optimize the beam characteristics. The beam is reflected by the cubic beam splitter, and the reflected beam is focused by the high-power objective lens. The aperture suppresses non-focal scattered light and guides the beam to the test area of ​​the sample. The measurement module is used to acquire measurement data related to reflected light, including an illuminance sensor; after the light beam is irradiated onto the sample by the optical module, the reflected light from the sample surface is captured by the illuminance sensor to obtain measurement data; The control module is used to control the system's start and stop, receive measurement data, and convert analog and digital signals. It includes a core control unit, a sensor unit, and a digital-to-analog converter module. The core control unit starts the equipment, receives the measurement data transmitted by the measurement module through the sensor unit, and converts the analog measurement data into digital signals through the digital-to-analog converter module. The dynamic adjustment module is used to receive the motor displacement compensation amount from the control module, generate X, Y, and Z axis motor control commands, drive the motor to run, collect the actual position of the motor through the position sensor and feed it back, and correct the deviation through PID closed-loop adjustment until the illuminance sensor captures the effective reflected light, thereby realizing the dynamic positioning of the area to be measured. The point cloud computing module is used to calculate the depth and width data of the sample micro-nano structure in real time. It receives digital signals from the control module and obtains the sample depth and width data through point cloud algorithm fitting.

[0031] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A non-contact laser micro / nano measurement dynamic adjustment method, characterized in that, include: Import the fixed motion trajectory parameters of the object to be tested, generate motor prediction motion commands, and drive the motor to run synchronously; By adjusting the motor position in a closed loop, the test area of ​​the object under test is locked, and the motor motion trajectory parameters are recorded. A laser beam is emitted, processed, and then irradiated onto the locked area to be measured, and the initial optical path parameters are recorded. The reflected light signal is detected in real time by a light intensity sensor to obtain the capture result of the effective reflected light. When no effective reflected light is captured, a light reflection path model is constructed based on the motor motion trajectory parameters and the initial optical path parameters; Based on the light reflection path model, the motor displacement compensation amount is obtained by calculation; based on the motor displacement compensation amount, the relative position of the area to be measured and the light path is adjusted until the illuminance sensor captures the effective reflected light, and the measurement data is acquired and converted into a digital signal. Based on the obtained digital signal, the depth and width data of the sample are calculated by fitting the point cloud algorithm.

2. The non-contact laser micro / nano measurement dynamic adjustment method according to claim 1, characterized in that, The process of importing fixed motion trajectory parameters of the object under test, generating motor prediction motion commands, and driving the motor to run synchronously includes: The system acquires and imports fixed motion trajectory parameters of the object under test, including dynamic motion trajectory equations, relative position coordinates of the test area, and motion velocity curves of the X, Y, and Z axes. It then uses a cubic spline interpolation trajectory analysis algorithm to calculate the predicted dynamic center coordinates of the test area at each moment in real time. Based on these predicted dynamic center coordinates, it plans the running speeds of the X, Y, and Z axis motors and generates predicted motor motion commands, including dynamic running speeds of each axis, real-time target tracking coordinates, and preset displacements for each axis. Finally, it drives the X, Y, and Z axis motors to run synchronously according to these predicted motion commands.

3. The non-contact laser micro / nano measurement dynamic adjustment method according to claim 1, characterized in that, The process of adjusting the motor position via closed-loop control, locking the test area of ​​the object under test, and recording the motor motion trajectory parameters includes: The actual position of each axis is collected in real time by the position sensor integrated in the motor, and the measured dynamic center coordinates of the current test area are obtained by conversion. The measured dynamic center coordinates of the test area are compared with the predicted dynamic center coordinates of the test area to obtain the position deviation value. When the position deviation value exceeds the preset positioning deviation threshold, the motor position is corrected in real time by the PID closed-loop adjustment algorithm. When the position deviation value is less than or equal to the preset positioning deviation threshold, the test area is determined to be locked. The motor motion trajectory parameters are recorded, including the actual displacement of the X, Y, and Z axes, the measured dynamic center coordinates of the test area, and the synchronization error of each axis displacement. The synchronization error of each axis displacement is the absolute value of the difference between the actual displacement of each axis and the preset displacement of each axis.

4. The non-contact laser micro / nano measurement dynamic adjustment method according to claim 1, characterized in that, The emitted laser beam, after processing, illuminates the locked test area, and the initial optical path parameters are recorded, including: A laser beam is emitted from a laser and sequentially expanded and collimated by a beam expander, reflected and redirected by a cubic beam splitter, focused by a high-magnification objective, and suppressed by an aperture to suppress non-focal scattered light, thus completing beam processing. The processed laser beam is then guided to the locked test area to measure the dynamic center coordinates. The initial core optical path parameters are recorded, including the beam propagation direction after beam processing, the optimized optical path parameters of the beam expander, the reflection angle parameters of the cubic beam splitter, the focusing configuration parameters of the high-magnification objective, and the aperture parameters.

5. The non-contact laser micro / nano measurement dynamic adjustment method according to claim 1, characterized in that, The method of obtaining the effective reflected light capture result by real-time detection of reflected light signals using a light intensity sensor includes: The reflected light signal of the area under test is captured in real time by a light intensity sensor. When the peak value of the reflected light intensity signal detected by the light intensity sensor is greater than the preset effective light intensity threshold and the duration is greater than the preset effective time threshold, it is determined that effective reflected light has been captured. When at least one condition is not met, it is determined that effective reflected light has not been captured.

6. The non-contact laser micro / nano measurement dynamic adjustment method according to claim 1, characterized in that, When no effective reflected light is captured, a light reflection path model is constructed based on the motor motion trajectory parameters and initial optical path parameters, including: When it is determined that no effective reflected light has been captured, the motor motion trajectory parameters and initial optical path parameters are used as input parameters for the light reflection path model. A three-dimensional rectangular coordinate system is established with the measured dynamic center coordinates of the area under test as the origin. The three-dimensional coordinates of the beam expander, cubic beam splitter, high-magnification objective, and aperture are calculated and mapped to the three-dimensional rectangular coordinate system based on the physical installation spacing of each optical element and the initial optical path parameters. Based on the core parameters of the initial optical path, the transformation parameters of each optical element are obtained. Specifically, the beam expander optical path optimization parameters are transformed into beam divergence angle correction coefficients, the cubic beam splitter reflection angle parameters are transformed into three-dimensional coordinates of the normal vector of the reflecting surface, the high-magnification objective focusing configuration parameters are transformed into focal length and numerical aperture, and the aperture parameters are transformed into light transmission range. The synchronous error of each axis displacement is transformed into the coordinate offset of the area under test, superimposed on the measured dynamic center coordinates of the area under test to obtain the actual incident point coordinates. The least squares method is used to fit the surface contour plane equation of the area under test and solve for the normal vector at the actual incident point. Starting from the coordinates of the laser emission point, an initial incident ray direction vector is generated by combining the beam propagation direction and the beam divergence angle correction coefficient. The initial incident ray direction vector is then adjusted by substituting the transformation parameters of each optical element to obtain the incident ray straight line equation. The actual incident point coordinates are then substituted into the incident ray straight line equation to correct and obtain the final incident ray direction vector. Based on the reflection law formula, the reflected ray direction vector is calculated by combining the final incident ray direction vector and the normal vector at the actual incident point. The reflected ray straight line equation is then generated based on the reflected ray direction vector. The light reflection path model is constructed by calling parameters, setting up a coordinate system, transforming parameters, and calculating the trajectories of incident and reflected rays.

7. The non-contact laser micro / nano measurement dynamic adjustment method according to claim 1, characterized in that, The motor displacement compensation amount is obtained by solving the light reflection path model, including: The effective geometric parameters of the existing illuminance sensor receiving surface are extracted, including the plane equation and effective boundary coordinates of the receiving surface. The equation of the reflected ray line output from the constructed light reflection path model is combined with the plane equation of the receiving surface to calculate the theoretical landing point coordinates of the reflected ray. By comparing the theoretical landing point coordinates with the effective boundary coordinates of the receiving surface, the deviation direction and deviation distance of the reflected ray that did not fall on the illuminance sensor receiving surface are obtained. Based on the trajectory calculation logic of the incident ray and the reflected ray in the light reflection path model, the laser incident angle correction amount and laser focal point position correction amount required to eliminate the deviation are derived in reverse according to the deviation direction and deviation distance. The laser incident angle correction amount and laser focal point position correction amount are converted into the displacement adjustment requirements of the X, Y, and Z axis motors as motor displacement compensation amounts, including the compensation direction and compensation amount values ​​of each axis motor.

8. The non-contact laser micro / nano measurement dynamic adjustment method according to claim 1, characterized in that, The process of adjusting the relative position of the area to be measured and the optical path based on the motor displacement compensation until the illuminance sensor captures the effective reflected light, acquiring measurement data and converting it into a digital signal includes: Based on the motor displacement compensation, a motor linkage control command is generated to drive the X, Y, and Z axis motors to adjust the relative position of the area under test and the optical path, thereby changing the incident angle of the laser beam. During the motor's adjustment action, the reflected light signal of the area under test is continuously captured by the illuminance sensor. When effective reflected light is captured, the reflected light measurement data of the current optical path is obtained, including the reflected light intensity distribution, optical path difference, and reflected light phase information. The acquired reflected light measurement data is converted into a digital signal, filtered and denoised, and then stored.

9. The non-contact laser micro / nano measurement dynamic adjustment method according to claim 1, characterized in that, The process of fitting and processing the obtained digital signal using a point cloud algorithm to calculate the depth and width data of the sample includes: The stored digital signal is converted into three-dimensional spatial point cloud data. Specifically, the Z-axis coordinates of each measurement point are calculated using the reflected light phase information and optical path difference quantization data, and the X and Y-axis coordinates of each measurement point are calculated using the reflected light intensity distribution quantization data combined with the laser beam scanning trajectory, thus forming a three-dimensional point cloud dataset. The 3D point cloud dataset is preprocessed by sequentially performing point cloud deduplication, statistical filtering, and data downsampling to obtain preprocessed point cloud data. A point cloud fitting algorithm is then used to process the preprocessed point cloud data to calculate sample depth and width data. Specifically, to calculate sample depth, the point cloud data of the sample's test area is selected, and the 3D surface equation of the sample surface is obtained through least squares fitting. Using the XY plane of the 3D Cartesian coordinate system as a preset reference plane, the Z-axis distance between each point on the surface equation and the reference plane is calculated to represent the sample depth data at the corresponding location. The maximum, minimum, and gradient values ​​of the sample depth data are extracted to form complete depth information. To calculate sample width, the projection point set of the 3D point cloud data onto the preset reference plane is extracted. The Canny edge detection algorithm is used to identify the boundary contour of the projection point set, and the equation of the closed curve of the boundary contour is obtained through polynomial fitting. The maximum distance of the closed curve in the preset measurement direction is calculated to represent the width data of the sample in the corresponding direction. The sample depth and width data are then integrated and output.

10. A non-contact laser micro / nano measurement dynamic adjustment system, using the non-contact laser micro / nano measurement dynamic adjustment method according to any one of claims 1-9, characterized in that, include: Optical module, measurement module, control module, dynamic adjustment module, and point cloud computing module; The optical module is used to adjust the beam and focus it onto the surface of the sample to be tested. It includes a laser, a cubic beam splitter, a high-power objective lens, and an aperture. The laser emits a beam, which is expanded and collimated by a beam expander to optimize the beam characteristics. The beam is reflected by the cubic beam splitter, and the reflected beam is focused by the high-power objective lens. The aperture suppresses non-focal scattered light and guides the beam to the test area of ​​the sample. The measurement module is used to acquire measurement data related to reflected light, including an illuminance sensor; after the light beam is irradiated onto the sample by the optical module, the reflected light from the sample surface is captured by the illuminance sensor to obtain measurement data; The control module is used to control the system's start and stop, receive measurement data, and convert analog and digital signals. It includes a core control unit, a sensor unit, and a digital-to-analog converter module. The core control unit starts the equipment, receives the measurement data transmitted by the measurement module through the sensor unit, and converts the analog measurement data into digital signals through the digital-to-analog converter module. The dynamic adjustment module is used to receive the motor displacement compensation amount from the control module, generate X, Y, and Z axis motor control commands, drive the motor to run, collect the actual position of the motor through the position sensor and feed it back, and correct the deviation through PID closed-loop adjustment until the illuminance sensor captures the effective reflected light, thereby realizing the dynamic positioning of the area to be measured. The point cloud computing module is used to calculate the depth and width data of the sample micro-nano structure in real time. It receives digital signals from the control module and obtains the sample depth and width data through point cloud algorithm fitting.

Images