Method for manufacturing complex surface fly-eye lens and detection device

Abstract

The application relates to a complex surface compound eye lens manufacturing method and a detection device. A pre-processed lens substrate is placed on a cutting processing end to determine a cutting tool path; the cutting surface shape data of the lens substrate is acquired through in-situ detection on the cutting processing end; the surface shape of the lens substrate is restored through a reconstruction algorithm based on the cutting surface shape data, and surface shape error is calculated; the surface shape error is fed back to the cutting processing end, the cutting processing end automatically generates compensation cutting data according to the surface shape error, and the machining process of the lens substrate is adjusted through the compensation cutting data. Through the method, a closed-loop working mode of machining and in-situ detection is realized, machining error is reduced, and a full-aperture consistent super-smooth cutting mirror surface is obtained.

Description

Technical Field

[0001] This application relates to the field of lens manufacturing technology, and in particular to a method and testing device for manufacturing complex surface compound eye lenses. Background Technology

[0002] Laser beam combining technology has wide applications in laser processing, deep space exploration, and other fields. With the development of fiber lasers, aperture beam combining technology using fiber lasers as the laser source has become the mainstream solution for laser beam combining. However, this solution faces some difficulties in addressing the thermo-optical distortions caused by high-energy lasers, which limits its practical application.

[0003] A major problem encountered by laser aperture beam combining schemes in high-energy laser processing is that the absorption of high-energy laser light by the collimator's mechanical structure leads to thermo-optical distortion. This distortion causes problems such as diffused target laser spot, decreased energy concentration, and reduced optical axis alignment. These issues are significant for precision machining and accurate measurement.

[0004] In solving these problems, the fabrication of surface compound eye lenses is particularly important. However, due to the unavoidable errors during the cutting process, the resulting surface compound eye lenses have excessively high roughness, making it difficult to meet the experimental requirements for continuous surface fiber laser collimation and beam combining. Summary of the Invention

[0005] Therefore, it is necessary to provide a method and testing device for manufacturing complex surface compound eye lenses that can reduce processing errors and obtain a cutting mirror surface with small surface roughness and ultra-smoothness throughout the entire aperture, in order to address the above-mentioned technical problems.

[0006] A method for fabricating a complex surface compound eye lens, the method comprising:

[0007] Place the pre-machined lens substrate on the cutting end and determine the cutting tool path;

[0008] At the cutting end, in-situ detection is used to acquire the cutting surface shape data of the lens substrate;

[0009] Based on the cutting surface shape data, the surface shape of the lens substrate is restored by a reconstruction algorithm, and the surface shape error is calculated.

[0010] The surface shape error is fed back to the cutting end, which automatically generates compensating cutting data based on the surface shape error, and adjusts the processing of the lens substrate using the compensating cutting data.

[0011] In one embodiment, the pre-machined lens substrate is placed on the cutting end, and the cutting tool path is determined, including:

[0012] The pre-processed lens substrate is placed on the cutting end, the lens substrate including the collimation unit region to be processed and the transition region;

[0013] The collimation unit region uses the equal chord length method and the equal parameter method to determine the cutting tool path;

[0014] The cutting tool path in the transition region is determined using a two-dimensional spatial curve cubic spline interpolation method.

[0015] In one embodiment, at the cutting end, in-situ detection acquires the cutting surface shape data of the lens substrate, including:

[0016] During the cutting stage, the cutting surface shape data of the lens substrate is acquired in real time through a helical scanning method.

[0017] In one embodiment, the spiral scanning method is designed using a parametric approach;

[0018] The parameters in the parameter method include sampling frequency, C-axis rotation speed, X-axis transverse scanning speed, and data acquisition time synchronization.

[0019] In one embodiment, the cutting surface shape data includes the radius and angular position along any point direction, which are acquired in real time;

[0020] The expression for the polar coordinate measurement data points of the radius and the angular position is:

[0021]

[0022] In the formula, R i Let x be the radius in the direction of the measurement point i. i Let θ be the x-coordinate of the measurement point i in the polar coordinate system. i C is the angular position of the measurement point i. i Let be the angular coordinates of measurement point i in the polar coordinate system, and n be the total number of sampling points.

[0023] In one embodiment, the reconstruction algorithm includes: converting the obtained polar coordinate measurement data points of the radius and the angle position into a Cartesian coordinate system;

[0024] The coordinate transformation formula is expressed as:

[0025]

[0026] In the formula, X i Let X and Y be the coordinates of the measured point i in the Cartesian coordinate system. i Let Z be the Y-coordinate of the measured point i in the Cartesian coordinate system. iThis is the measured height of the surface in the Z direction at measurement point i.

[0027] In one embodiment, based on the cutting surface shape data, the surface shape of the lens substrate is reconstructed using a reconstruction algorithm, and the surface shape error is calculated, including:

[0028] Based on the radius and angle position along any point, the obtained polar coordinate measurement data points of the radius and angle position are converted into Cartesian coordinates to obtain reconstructed surface point matrix data;

[0029] By subtracting the initial surface design data from the reconstructed surface dot matrix data, the error distribution dot matrix data of the processed surface is obtained.

[0030] A complex surface compound eye lens fabrication and testing device includes: a sensor measurement probe, a spectral confocal analyzer, a signal input acquisition card, a signal synchronous acquisition module, and an ultra-precision turning motion controller PMAC;

[0031] The sensor measurement probe is aligned with the cutting end to obtain backlight information;

[0032] The spectral confocal analyzer is connected to the sensor measurement probe via optical fiber, and is used to receive the backlight information, analyze the backlight information, convert it into radius and angular position information, and output an analog voltage signal;

[0033] The signal input acquisition card is connected to the spectral confocal analyzer via serial communication and is used to receive the analog voltage signal, perform digital-to-analog conversion, and obtain a digital voltage signal.

[0034] The ultra-precision turning motion controller PMAC is located at the cutting end and is connected to the signal input acquisition card via serial communication to acquire the digital voltage signal from the signal input acquisition card and perform analog-to-digital conversion.

[0035] The signal synchronization acquisition module is internally connected to the motion controller PMAC to synchronously acquire position information and digital voltage signals, and generate a reconstructed surface dot matrix dataset based on the radius and angle position information and voltage information.

[0036] In one embodiment, a displacement lifting platform is also included;

[0037] The displacement lifting platform is fixed below the sensor measuring probe and is used to adjust the height of the sensor measuring probe.

[0038] In one embodiment, a computer terminal is also included;

[0039] The computer terminal is connected to the spectral confocal analyzer via a network port and is used to control the various functions of the spectral confocal analyzer.

[0040] The aforementioned method and testing device for manufacturing complex surface compound eye lenses involves placing a pre-processed lens substrate on the cutting end and determining the cutting tool path. At the cutting end, in-situ detection acquires the cutting surface shape data of the lens substrate. Based on the cutting surface shape data, a reconstruction algorithm reconstructs the surface shape of the lens substrate and calculates the surface shape error. The surface shape error is fed back to the cutting end, which automatically generates compensating cutting data based on the surface shape error to adjust the processing of the lens substrate.

[0041] This invention constructs a cutting tool path to ensure a smooth workpiece surface during lens substrate machining, achieving a surface roughness at the nanometer level. Simultaneously, a reconstruction algorithm restores the surface shape of the lens substrate, feeding the calculated surface shape error back to the cutting end, thus realizing a closed-loop working mode of machining and in-situ detection. This reduces machining errors and yields a uniformly smooth cutting mirror surface across the entire aperture. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of a method for fabricating a complex surface compound eye lens in one embodiment;

[0043] Figure 2 The image shows an engineering drawing of a compound eye lens in one embodiment, wherein (a) is a three-dimensional view of the lens substrate, (b) is a schematic diagram of the collimation unit region structure, (c) is a top view of the lens substrate, and (d) is a side view of the lens substrate.

[0044] Figure 3 This is a schematic diagram illustrating the principle of spectral confocal sensing technology in one embodiment;

[0045] Figure 4 This is a schematic diagram of a detection device for fabricating complex surface compound eye lenses in one embodiment.

[0046] Figure 5 This is a schematic diagram illustrating the use of a tilted plane mirror to assist probe alignment in one embodiment;

[0047] Explanation of reference numerals in the attached figures:

[0048] Collimation unit region 11, transition region 22. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0050] It is worth noting that the complex surface compound eye lens produced by this invention is mainly a complex optical surface of a freeform compound eye lens with seven channels arranged in a regular hexagon. It can also be applied to the processing of different types of complex optical surfaces such as five-channel, six-channel, or eight-channel lenses.

[0051] When selecting a cutting lathe, it is generally advisable to choose one that can process surfaces with greater undulations, offers more flexible machining methods, and features high-precision slow-tool servo technology with three-axis linkage. Furthermore, because this complex surface compound eye lens requires extremely high precision and quality, the selected cutting lathe should also be capable of ultra-precision turning.

[0052] Example 1

[0053] like Figure 1 As shown, a method for fabricating a complex surface compound eye lens is provided, including the following steps:

[0054] Step 102: Place the pre-machined lens substrate on the cutting end and determine the cutting tool path.

[0055] Understandably, before pre-processing, it is necessary to design the processing engineering drawings for the compound eye lens, such as... Figure 2 As shown in (a), the lens substrate includes a collimation unit region 11 and a transition region 22. The collimation unit region 11 needs to have a smooth surface with a roughness at the nanometer level, and its surface shape accuracy needs to be within the measurement range of the interferometer. The laser energy proportion in the transition region 22 is very low, and it has little impact on the effective laser beam energy after collimation and beam combining. Therefore, the actual surface shape quality requirements for this region are not high; ensuring the basic bright surface optical transmittance is sufficient to meet the laser energy transmission requirements. Figure 2 Figures (b), (c), and (d) show schematic diagrams of the dimensional design for compound eye lens processing. Preferably, the processing of the lens substrate should meet the following requirements: optical axis perpendicularity less than 10 μm, surface roughness less than 1 nm or 2 nm, RMS value of the transmitted wave aberration (ideal imaging) within 20 mm of the effective aperture less than λ / 50, center distance tolerance of the collimation unit distribution less than 70 mm ± 10 μm, and mirror thickness tolerance less than 24 mm ± 1 mm. Simultaneously, during the cutting process, the impact of tool wear on the cutting surface quality should be avoided to obtain a uniformly smooth cutting surface across the entire aperture.

[0056] Specifically, the pre-processed lens substrate is placed on the cutting end. To avoid stress deformation of the lens substrate, vacuum adsorption is preferably used to fix the pre-processed lens substrate on the cutting end. The end face is provided with an annular groove, which is connected to a vacuum device. The vacuum degree can be adjusted by changing the adsorption pressure, so that the adsorption force on the end face matches the spindle speed and the mass of the workpiece, thus meeting the requirements of the cutting process and ensuring that no stress deformation occurs to the optical element to be processed.

[0057] In one embodiment, in the ultra-precision turning machining process, the determination of the cutting tool path directly affects the cutting effect, surface quality, and machining efficiency. Therefore, the cutting tool path in the collimation unit region 11 is determined using the equal chord length method and the equal parameter method; the cutting tool path in the transition region is determined using the two-dimensional spatial curve cubic spline interpolation method. This is because the spindle C-axis in the cutting lathe is a rotary position servo axis, and the end face of the spindle C-axis is the cutting end, requiring the main cutting motion to be integrated with the servo feed motion. To ensure the uniform motion of the ultra-precision turning spindle C-axis and the scanning axis X-axis, the cutting tool path in the collimation unit region is determined using the equal chord length method and the equal parameter method. The step length is determined by the equal rotation angle method, and the line spacing is determined by the equal parameter method; both methods jointly determine the cutting tool path.

[0058] The cutting tool path design in the transition region differs from traditional spatial surface extension methods such as extension along the workpiece surface direction, horizontal stretching of the boundary, and slope stretching of the boundary. Instead, it adopts a two-dimensional spatial curve cubic spline interpolation method to compress the surface sag and slope of the transition region as much as possible, while suppressing possible high-frequency tool trajectory errors and achieving a smooth transition.

[0059] It is worth noting that the lens base is fixed on the cutting end by a fixture. The fixture is preferably an eccentric aluminum alloy frame, with a joint precision of <1μm between it and the lens base edge. The joint is firmly bonded with adhesive to minimize and uniformly distribute stress on the part during clamping. Simultaneously, the vibration isolation and the stability of temperature and humidity control in the machining environment affect the surface accuracy of the machined part. Here, the ambient temperature is controlled at 24℃ and the ambient humidity at 27%. During cutting, the coolant spray flow rate is maintained at a high degree of uniformity.

[0060] Step 104: At the cutting end, in-situ detection is used to obtain the cutting surface shape data of the lens substrate.

[0061] Specifically, the in-situ detection mentioned here refers to the process of aligning a probe with the cutting end, acquiring the cutting surface shape data of the lens substrate, and then performing surface shape error detection.

[0062] There are three key parameters in machining: spindle speed, depth of cut, and tool rake angle. The depth of cut considers both surface roughness requirements and machining efficiency to obtain the optimal surface roughness for optical parts; a depth of cut of 3µm is preferred. For the tool rake angle, a -20° rake angle corresponds to the largest feed rate range, which is most conducive to slip along the slip system, achieving plastic cutting and obtaining lower surface roughness. Therefore, a -20° rake angle is preferred for the cutting tool. Different materials being machined have different structures and physicochemical properties, each with its own optimal turning spindle speed. At this speed, selecting an appropriate tool and depth of cut can minimize the root mean square value of the part's surface roughness. Above or below this speed, regardless of the tool and depth of cut selection, optimal surface roughness and finish cannot be achieved. Therefore, in the finish turning stage, correctly selecting the machine tool spindle speed is a key parameter for obtaining the optimal surface roughness of optical parts; here, a spindle speed of 500 r / min is chosen.

[0063] Furthermore, based on spectral confocal sensing technology, the cutting data of the lens substrate is acquired in real time. The core of the spectral confocal sensing measurement system is a white light interferometer. The beam splitter separates the white light from the extended light source into a reference beam reflected from the reference mirror and a measurement beam transmitted from it. The two beams pass through an extinction pinhole and form interference fringes on the camera detector. Because white light has a large wavelength range and a short coherence length, the interference of two white light beams can be equivalent to the combination of interferences of closely packed monochromatic lights. The monochromatic interference fringes superimpose, and the synthesized interference signal can be approximated by the Gaussian fringe contrast envelope. The highest contrast occurs at the zero-order fringe position, corresponding to zero optical path difference, while the contrast becomes blurred further away from the zero-order fringe.

[0064] like Figure 3 The diagram shows the principle of the provided spectral confocal sensing technology. After passing through the objective lens, the white light source diffracts light of different wavelengths. Only light with wavelength λM can be focused on point M on the surface being measured. The light is reflected by the surface being measured and returns to the beam splitter through the original incident light path. After the beam splitter changes the direction, it finally points to the light wave detector. The detection pinhole at the reflection imaging point located at the measured point M filters out all monochromatic wavelengths corresponding to points above or below M in the optical axis direction, allowing only light with wavelength λM to pass through.

[0065] White light sources also contain light of different wavelengths, which can be diffracted into different wavelengths after passing through the objective lens. After filtering, only light with a specific wavelength of λM can be successfully focused on point M on the surface being measured. The light then returns to the beam splitter through the previous incident path due to reflection. The beam splitter changes the beam direction, directing the light towards the optical detector. The probe pin at the reflection imaging point of the measured point M filters out all monochromatic wavelengths corresponding to those above or below point M along the optical axis, specifically allowing only light with wavelength λM to pass through. During white light interferometry, the entire mirror under test is scanned non-contactly according to the set path. The length of the measurement beam path changes, while the length of the reference beam path remains constant. The position of the highest contrast fringe moves laterally within the detector sensor measurement probe plane. By simultaneously acquiring the height information and corresponding coordinate position of the measured surface, the surface shape of the mirror under test can be calculated. To achieve efficient and high-precision measurement using spectral confocal sensing technology, a corresponding high-speed scanning mode must also be set.

[0066] In one embodiment, the cutting surface data of the lens substrate is acquired in real time during the cutting stage using a helical scanning method. The helical scanning method has the highest scanning efficiency and the least fluctuation. While the workpiece rotates continuously along the C-axis, the probe performs a transverse scan along the X-axis, achieving high-speed scanning to cover the entire surface.

[0067] In one embodiment, a helical scanning method is designed using a parametric approach. Key parameters in this approach include sampling frequency, C-axis rotational speed, X-axis lateral scanning speed, and data acquisition time synchronization. The C-axis rotational speed and the corresponding X-axis lateral scanning speed characterize the time cost of a single surface shape detection; higher speeds result in higher detection efficiency. The sampling frequency characterizes the efficiency of data point acquisition in a single surface detection; higher frequencies lead to denser data points and higher surface shape reconstruction. Data acquisition time synchronization refers to the time synchronization of acquiring the coordinate information and surface height information of the sampling points. Only when the surface height error at different locations is not significant relative to the next location due to asynchronous data acquisition at a given sampling point can the acquired data be used to correctly reconstruct the surface shape. Therefore, the requirement for data acquisition time synchronization in the in-situ detection system is related to the surface slope of the mirror under inspection and the time requirement for completing a single surface shape detection. Conversely, high acquisition time synchronization enables high-efficiency, high-precision, and high-slope surface shape detection.

[0068] Step 106: Based on the cutting surface shape data, the surface shape of the lens substrate is restored by a reconstruction algorithm, and the surface shape error is calculated.

[0069] It is understandable that before reconstructing the surface shape, it is necessary to first calculate the coordinate form of the spiral scan and convert it into the Cartesian coordinate system corresponding to the matrix analysis in MATLAB.

[0070] In one embodiment, the cutting surface profile data includes the radius and angular position along any point direction, acquired in real time.

[0071] The expression for the polar coordinate measurement data points of radius and angular position is:

[0072]

[0073] In the formula, R i Let x be the radius in the direction of the measurement point i. i Let θ be the x-coordinate of the measurement point i in the polar coordinate system. i C is the angular position of the measurement point i. i Let be the angular coordinates of measurement point i in the polar coordinate system, and n be the total number of sampling points.

[0074] In one embodiment, the obtained polar coordinate measurement data points of radius and angular position are converted to Cartesian coordinates, and the coordinate transformation formula is expressed as:

[0075]

[0076] In the formula, X i Let X and Y be the coordinates of the measured point i in the Cartesian coordinate system. i Let Z be the Y-coordinate of the measured point i in the Cartesian coordinate system. i To measure the height of the Z-direction surface at point i, the point matrix represented by formula (2) is substituted into the matrix analysis software MATLAB to reconstruct the surface shape of the lens substrate.

[0077] Step 108: Feedback the surface shape error to the cutting end. The cutting end automatically generates compensation cutting data based on the surface shape error, and adjusts the processing of the lens substrate using the compensation cutting data.

[0078] Specifically, based on cutting data, a reconstruction algorithm is used to obtain reconstructed surface shape lattice data. Subtracting the initial surface shape design data from the reconstructed surface shape lattice data yields the error distribution lattice data for the current machining surface. This error distribution lattice data is then fed back to the motion cutting end of the ultra-precision turning machine, automatically generating a corresponding compensation machining program to achieve targeted mirror surface shape repair. In essence, the cutting data is continuously acquired during machining using key design parameters. The reconstructed surface shape lattice data is calculated from this continuously acquired cutting data. This reconstructed surface shape lattice data is compared with the initial surface shape design data, and through multiple iterative machining processes, a machined surface shape with errors meeting manufacturing precision requirements is obtained.

[0079] Example 2

[0080] like Figure 4As shown, to realize the above-mentioned method for fabricating complex surface compound eye lenses, a detection device for fabricating complex surface compound eye lenses is provided. This device includes a sensor measurement probe, a spectral confocal analyzer, a signal input acquisition card, a signal synchronous acquisition module, a PMAC (Precision Machining Controller), and a computer terminal, wherein:

[0081] The sensor's measuring probe is aligned with the cutting end to obtain backlight information.

[0082] The spectral confocal analyzer is connected to the sensor measurement probe via optical fiber to receive the reflected light information, analyze the reflected light information, convert it into radius and angular position information, and output an analog voltage signal.

[0083] The signal input acquisition card is connected to the spectral confocal analyzer via serial communication to receive analog voltage signals, perform digital-to-analog conversion, and obtain digital voltage signals.

[0084] The ultra-precision turning motion controller PMAC is located at the cutting end and is connected to the signal input acquisition card via serial communication. It is used to acquire the digital voltage signal from the signal input acquisition card and perform analog-to-digital conversion.

[0085] The signal synchronization acquisition module and the motion controller PMAC are internally connected to synchronously acquire position information and digital voltage signals, and generate a reconstructed surface dot matrix dataset based on the radius and angle position information and voltage information.

[0086] The computer terminal is connected to the confocal spectral analyzer via Ethernet communication and is used to control the various functions of the confocal spectral analyzer.

[0087] Specifically, the sensor measuring probe is fixed on the displacement lifting platform by a clamping device. The height of the sensor measuring probe is adjusted by the displacement lifting platform to align with the spindle rotation center in the cutting lathe. Preferably, the clamping device is a designed aluminum alloy fixture, and the displacement lifting platform is a PI displacement lifting platform with Z-direction movement.

[0088] It is worth noting that the key to achieving high-precision helical scanning is aligning the spindle rotation center with the center of the sensor measurement probe. To achieve this alignment, such as... Figure 5 As shown, a tilted plane mirror is used to assist in the centering of the sensor measuring probe. A tilted plane mirror is placed near the center of rotation of the main shaft. When the auxiliary sensor measuring probe deviates from the center of rotation, the displacement Z trajectory measured by the auxiliary sensor measuring probe as the main shaft rotates is approximately a cosine curve.

[0089] Specifically, first, adjust the displacement lifting platform to a position approximately aligned with the center height of the C-axis and tighten it with locking screws. When the C-axis rotates at low speed, observe the surface height curve measured by the sensor probe in real time on the computer terminal connected to the spectral confocal analyzer. Find the absolute angle value of the C-axis corresponding to the peak value (highest or lowest), record the X-axis position 1 and the sensor probe peak value 1 at this time, and set this position as the zero point of the C-axis relative position, assuming the tilt direction of the plane tilting mirror is in the X-axis direction. Control the C-axis to rotate precisely 180 degrees, record the X-axis position 2 and the sensor probe peak value 2 at this time, compare the two peak values, and if the difference is greater than the accuracy requirement, calculate the average of the two X-axis positions and control the X-axis carrying the sensor probe to laterally translate to the average value position. Repeat the above operation until the difference between the measured peak values ​​of the sensor probe before and after rotating the C-axis by 180 degrees meets the accuracy requirement, completing the center alignment in the X-axis direction. Next, set this position as the zero point of the X-axis relative position and fix the X-axis position. Perform the same centering operation on the height position of the PI displacement lifting stage. This completes the alignment of the spindle rotation center with the center of the scanning probe.

[0090] It is worth noting that when calculating the coordinates of the helical scan in Example 1, the center of rotation of the principal axis is the polar coordinate center in the reconstruction of the lens base surface shape. Here, the center coordinate of the lens base is X. center During the alignment process, X center Set it as the relative zero point of the X-axis position.

[0091] More specifically, the sensor measurement probe and the spectral confocal analyzer are connected via optical fiber. The spectral confocal analyzer outputs the measurement data from the sensor measurement probe in analog form (0–10V), corresponding to the 0–300μm surface profile height near the focal point. The signal input acquisition card adapted to the ultra-precision turning motion controller PMAC is a four-channel data acquisition card ACC-28E, which can acquire 0–10V single-ended analog voltage signals and convert them into 65535-bit digital voltage signals. Corresponding to the 0–300μm range of the spectral confocal sensor measurement probe, the surface profile height measurement accuracy of the analog-to-digital conversion is approximately 4.57nm, which is better than the sensor measurement probe's own resolution of 10nm. Therefore, the position measurement signal accuracy transmitted to the ultra-precision turning motion controller PMAC in this detection device is 10nm, which meets the detection requirements. After the spectral confocal analyzer is connected to the ultra-precision turning motion controller PMAC's signal input acquisition card ACC-28E, data acquisition and storage can be performed in the ultra-precision turning controller PMAC. To detect the shape of the mirror under test, the surface profile height corresponding to each acquisition point must first be accurately obtained. Therefore, the position information of the acquisition points and the voltage information representing the surface profile height of the mirror under test output by the spectral confocal analyzer must have a high degree of time synchronization. Here, a signal synchronization acquisition module for position and voltage signals based on the motion control terminal PMAC integrated development environment IDE is constructed, with the acquisition synchronization set to be better than 1ms and the maximum sampling frequency to 200Hz.

[0092] The signal synchronization acquisition module synchronously displays the absolute position signals of the X-axis, Z-axis, and C-axis in the IDE and the voltage signal input from the signal input acquisition card, and saves the acquired data points in the form of columns in a txt file, which serves as the raw data for constructing the test mirror shape in MATLAB during subsequent data processing.

[0093] In summary, the detection device in this embodiment can be considered as a motion control end and a signal transmission end. The motion control end is located at the cutting end and is controlled by the ultra-precision turning motion controller PMAC to achieve high-precision linear motion of the X-axis and Z-axis guideways of the ultra-precision turning end. The C-axis is the main spindle and can realize speed control and angle servo control. The X-axis, Z-axis, and C-axis of the cutting end can all be finely adjusted and aligned via handwheels. The displacement lifting platform is used to adjust the height position of the sensor measuring probe.

[0094] At the signal transmission end, the spectral confocal analyzer uses analog output as its signal interface, requiring the signal interface mode to be compatible with the digital signal mode of the signal synchronous acquisition module. Therefore, the reflected light signal from the sensor's measuring probe, after spectral analysis by the spectral confocal analyzer, is output as an analog signal to the signal input acquisition card. This enables signal transmission and mode conversion with the ultra-precision machining motion control terminal PMAC, and the signal synchronous acquisition module simultaneously acquires the position and elevation information of the detection point.

[0095] This closed-loop setup enables simultaneous machining and in-situ inspection, reducing machining errors and achieving a consistently smooth cutting mirror surface across the entire caliber.

[0096] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this description.

[0097] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for fabricating a complex surface compound eye lens, characterized in that, The method includes: Place the pre-machined lens substrate on the cutting end and determine the cutting tool path; At the cutting end, in-situ detection is used to acquire the cutting surface shape data of the lens substrate; Based on the cutting surface shape data, the surface shape of the lens substrate is restored by a reconstruction algorithm, and the surface shape error is calculated. The surface shape error is fed back to the cutting end, which automatically generates compensating cutting data based on the surface shape error, and adjusts the processing of the lens substrate using the compensating cutting data; The reconstruction algorithm includes: converting the obtained polar coordinate measurement data points of radius and angle positions into a Cartesian coordinate system; the coordinate transformation formula is expressed as: ； In the formula, For measurement points In the Cartesian coordinate system Location coordinates For measurement points In the Cartesian coordinate system Location coordinates For measurement points of Surface height measurement value For measurement points directional radius, For measurement points Angular position.

2. The method for fabricating a complex surface compound eye lens according to claim 1, characterized in that, Place the pre-machined lens substrate on the cutting end and determine the cutting tool path, including: The pre-processed lens substrate is placed on the cutting end, the lens substrate including the collimation unit region to be processed and the transition region; The collimation unit region uses the equal chord length method and the equal parameter method to determine the cutting tool path; The cutting tool path in the transition region is determined using a two-dimensional spatial curve cubic spline interpolation method.

3. The method for fabricating a complex surface compound eye lens according to claim 2, characterized in that, At the cutting end, in-situ detection acquires the cutting surface shape data of the lens substrate, including: During the cutting stage, the cutting surface shape data of the lens substrate is acquired in real time through a helical scanning method.

4. The method for fabricating a complex surface compound eye lens according to claim 3, characterized in that, The spiral scanning method is designed using a parametric approach. The parameters in the parameter method include sampling frequency, C-axis rotation speed, X-axis transverse scanning speed, and data acquisition time synchronization.

5. The method for fabricating a complex surface compound eye lens according to any one of claims 1 to 4, characterized in that, The cutting surface profile data includes the radius and angle position along any point obtained in real time; The expression for the polar coordinate measurement data points of the radius and the angular position is: ； In the formula, For measurement points In polar coordinates Location coordinates For measurement points Angular coordinates in polar coordinates This represents the total number of sampling points.

6. The method for fabricating a complex surface compound eye lens according to claim 5, characterized in that, Based on the cutting surface shape data, the surface shape of the lens substrate is reconstructed using a reconstruction algorithm, and the surface shape error is calculated, including: Based on the radius and angle position along any point, the obtained polar coordinate measurement data points of the radius and angle position are converted into Cartesian coordinates to obtain reconstructed surface point matrix data; The error distribution matrix data of the surface is obtained by subtracting the initial surface design data from the reconstructed surface matrix data.

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