Microlens array zoom module zoom method and imaging system

Abstract

The invention is suitable for the field of imaging, and discloses a micro lens array zoom module zoom method and an imaging system, and the method comprises the steps: obtaining a mapping relation table between a deviation objective lens working distance and a micro lens array state of a micro lens array zoom module; acquiring a laser spot image formed by irradiating the to-be-measured object with laser, and calculating the position of the to-be-measured object to the focal plane of the objective lens; determining an adjustment reference distance of the micro-lens array zoom module based on the position from the object to be measured to the focal plane of the objective lens, and comparing the adjustment reference distance with the mapping relation table to determine the micro-lens array state of the micro-lens array zoom module; and on the basis of the determined state of the microlens array, a focusing instruction is generated so as to realize automatic zooming of the microlens array zooming module, automatic zooming of the microlens array zooming module is realized, and the method has the advantages of extremely high focusing speed and high precision.

Description

Technical Field

[0001] The present invention relates to the field of imaging technology, and in particular to a microlens array zoom module zoom method and an imaging system. Background Art

[0002] In the optical automation inspection process of high-end equipment manufacturing such as semiconductors, integrated circuits, and display panels, high-power optical objective lenses are often used for inspection and imaging in order to achieve higher spatial resolution. Although high NA values ​​and high-power objective lenses can achieve high lateral resolution, the depth of field of the lens is narrow. For objects with highly complex surface morphology and warped surfaces, it is easy to exceed the depth of field during the measurement process, resulting in blurred imaging. Therefore, high-power microscopic imaging technology that can adapt to focal plane changes and has focal plane tracking is in great demand in the field of high-precision inspection.

[0003] Traditional microlens array zoom module automatic zoom technology includes two types. The first is active focus technology, which uses laser to measure the focal plane of the object, and feeds back the measurement value to the motion platform. The motion platform moves the imaging device in the direction of the optical axis according to the position of the focal plane to achieve focus image acquisition. Due to the large load of the motion platform and the camera itself, this technology has a slow focusing speed, and the mechanical movement is prone to jitter errors, which will introduce additional imaging errors in high-resolution imaging. The motion mechanism reciprocates for a long time, and there is a mechanical mode that causes poor accuracy. Second, passive focus technology, this technology acquires images at multiple positions near the focal plane along the optical axis, and selects the focus image by comparing the differences between the image groups through image algorithms. This technology does not require active laser emission for focal plane measurement, but it needs to collect multiple frames of images and design algorithms for focal plane screening, which takes a lot of time. At the same time, the motion mechanism is also required to move in the direction of the optical axis during the acquisition of multiple frames of images, and there are also problems of jitter errors and slow speed. Summary of the invention

[0004] The first object of the present invention is to provide a microlens array zoom module zoom method, which aims to solve the technical problems of jitter error and slow speed when focusing in existing imaging systems.

[0005] To achieve the above object, the solution provided by the present invention is: A zoom method for a microlens array zoom module, comprising: obtaining a mapping relationship table regarding the deviation from the working distance of the objective lens and the status of the micromirror array of the microlens array zoom module; obtaining a laser spot image formed by laser irradiating an object to be measured, and calculating the position of the object to be measured to the focal plane of the objective lens based on the laser spot image; determining an adjustment reference distance of the microlens array zoom module based on the position of the object to be measured to the focal plane of the objective lens, and comparing the adjustment reference distance with the mapping relationship table to determine the status of the micromirror array of the microlens array zoom module; generating a focusing instruction based on the determined status of the micromirror array to achieve automatic zoom of the microlens array zoom module.

[0006] Preferably, defining the working distance of the objective lens as the reference point, the positions deviating from the working distance of the objective lens include 2n + 1, and the status of the micromirror array includes 2n + 1. The 2n + 1 statuses of the micromirror array correspond to the 2n + 1 positions deviating from the working distance of the objective lens one by one.

[0007] Preferably, the obtaining a laser spot image formed by laser irradiating an object to be measured, and calculating the position of the object to be measured to the focal plane of the objective lens based on the laser spot image includes: obtaining a laser spot image formed by laser irradiating an object to be measured, and separating the spot in the laser spot image from the background to obtain a spot region image; removing the noise of the spot region image through erosion and dilation to obtain a processed spot region image; extracting the spot contour based on the processed spot region image; calculating the spot edge gradient based on the extracted spot contour, and determining the semi-circle direction and radius of the spot according to the calculated spot edge gradient; obtaining the relative focal plane position of the object based on the semi-circle direction, radius of the spot and the linear mapping relationship between the pre-calibrated radius and defocus amount.

[0008] Preferably, the determining an adjustment reference distance of the microlens array zoom module based on the position of the object to be measured to the focal plane of the objective lens, and comparing the adjustment reference distance with the mapping relationship table to determine the status of the micromirror array of the microlens array zoom module includes: respectively calculating the absolute values of the differences between the position of the measured object to the focal plane of the objective lens and multiple positions deviating from the working distance of the objective lens; using the position deviating from the working distance of the objective lens corresponding to the smallest absolute value as the adjustment reference distance; comparing the adjustment reference distance with the mapping relationship table to determine the status of the micromirror array of the microlens array zoom module.

[0009] Preferably, based on the determined state of the microlens array, a focusing instruction is generated and sent to the MEMS controller to adjust the state of the microlens array of the microlens array zoom module through the MEMS controller, so as to realize the automatic zoom of the microlens array zoom module, including: converting the determined state of the microlens array into an electrical signal, and generating a focusing instruction according to the electrical signal; sending the focusing instruction to the MEMS controller to adjust the state of the microlens array of the microlens array zoom module through the MEMS controller, so as to realize the automatic zoom of the microlens array zoom module.

[0010] The second object of the present invention is to provide a zoom imaging system for a microlens array zoom module, including a focal plane measurement unit, a zoom imaging unit, a processor and a MEMS controller. The focal plane measurement unit is connected to the processor. The MEMS controller is respectively connected to the processor and the microlens array zoom module of the zoom imaging unit. The focal plane measurement unit is used to collect a laser spot image formed by laser irradiation on an object to be measured and transmit the laser spot image to the processor. The processor is used to execute the microlens array zoom module zoom method as described above. The MEMS controller is used to receive a focusing instruction and adjust the state of the microlens array of the microlens array zoom module according to the focusing instruction, so as to realize the automatic zoom of the microlens array zoom module.

[0011] Preferably, the focal plane measurement unit includes a detection laser light source, a laser spot camera, a first lens, a second lens, a first beam splitter, a second beam splitter and an objective lens. The detection laser light source emits a laser spot, which passes through the first lens and the first beam splitter. The first beam splitter reflects the laser spot in the direction of the object to be measured, and after passing through the second beam splitter and the objective lens, irradiates the surface of the object to be measured. A laser spot reflected light is formed on the surface of the object to be measured. The laser spot reflected light passes through the objective lens and is reflected by the second beam splitter, and then enters the laser spot camera through the second lens. The laser spot camera is connected to the processor.

[0012] Preferably, the zoom imaging unit includes a microlens array zoom module, an imaging camera, a coaxial light source, a third beam splitter, a fourth beam splitter, a third lens, a fourth lens, and a filter. The coaxial light source emits coaxial illumination light. The coaxial illumination light passes through the third lens and the third beam splitter. After the third beam splitter directs the coaxial illumination light towards the direction of the object to be measured, it is irradiated onto the surface of the object to be measured through the filter, the first beam splitter, the second beam splitter, and the objective lens. Coaxial illumination light reflected rays are formed on the surface of the object to be measured. After passing through the objective lens, the second beam splitter, the first beam splitter, the filter, the third beam splitter, and the fourth beam splitter, the coaxial illumination light reflected rays are focused and reflected by the microlens array zoom module to form imaging reflected rays. The imaging reflected rays are irradiated onto the fourth beam splitter. The fourth beam splitter reflects the imaging reflected rays and passes them through the fourth lens into the imaging camera.

[0013] In this solution, by pre - constructing a mapping relationship table between the deviation from the working distance of the objective lens and the state of the micromirror array of the microlens array zoom module, combining the laser focal plane detection technology to obtain the object focal plane position in real - time, quickly matching the optimal micromirror state through numerical calculation, and then using the MEMS controller to adjust the microlens array zoom module, there is no need for mechanical moving parts, which has the advantages of extremely fast focusing speed, compact and reliable structure, high precision, and strong fault tolerance. At the same time, relying on the discretization calibration and look - up table mechanism to reduce the computational complexity, it can be flexibly adapted to different scenarios, and has great application prospects for the autofocus and high - definition imaging of complex - shaped and deformed objects. Description of the Drawings

[0014] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following - described drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0015] Figure 1 is a flowchart of the zoom method of the microlens array zoom module provided by the embodiment of the present invention; Figure 2 is a schematic structural diagram of the zoom imaging system of the microlens array zoom module provided by the embodiment of the present invention; Figure 3 is a schematic diagram of the principle of the laser focal plane detection technology provided by the embodiment of the present invention. Description of the Drawings: 10. Focal plane measurement unit; 11. Detection laser light source; 12. Laser spot camera; 13. First lens; 14. Second lens; 15. First beam splitter; 16. Second beam splitter; 17. Objective lens; 20. Zoom imaging unit; 21. Microlens array zoom module; 22. Imaging camera; 23. Coaxial light source; 24. Third beam splitter; 25. Fourth beam splitter; 26. Third lens; 27. Fourth lens; 28. Filter; 30. Processor; 40. MEMS controller; 50. Object to be measured. Detailed implementation manners

[0017] In the description of the present invention, the terms "first", "second", "third", "fourth", etc. (if any) in the specification, claims and the above drawings are used to distinguish similar objects, and do not necessarily describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances, so that the embodiments described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "comprising" or "having" and any variation thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units does not necessarily limit to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0018] For ease of understanding, the specific process of the embodiments of the present invention will be described below. Please refer to Figure 1 , in the embodiments of the present invention, a method for zooming a microlens array zoom module includes: S101. Obtain a mapping relationship table regarding the deviation from the working distance of the objective lens and the state of the microlens array of the microlens array zoom module; S102. Obtain a laser spot image formed by laser irradiating the object to be measured, and calculate the position of the object to be measured to the focal plane of the objective lens based on the laser spot image; S103. Determine an adjustment reference distance of the microlens array zoom module based on the position of the object to be measured to the focal plane of the objective lens, and compare the adjustment reference distance with the mapping relationship table to determine the state of the microlens array of the microlens array zoom module; S104. Generate a focusing instruction based on the determined state of the microlens array to achieve automatic zooming of the microlens array zoom module.

[0019] In this embodiment, in step S101, a mapping relationship table regarding the deviation from the working distance of the objective lens and the state of the micromirror array of the microlens array zoom module can be pre-constructed, specifically including: obtaining multiple positions deviating from the working distance of the objective lens; collecting the state of the microlens array of the microlens array zoom module corresponding to each position deviating from the working distance of the objective lens; establishing a one-to-one mapping relationship between all positions deviating from the working distance of the objective lens and the state of the microlens array of the microlens array zoom module, so as to obtain a mapping relationship table regarding the position deviating from the working distance of the objective lens and the state of the micromirror array of the microlens array zoom module.

[0020] In this embodiment, the working distance of the objective lens refers to the appropriate distance from the front end of the objective lens to the surface of the observed object. On this basis, a series of positions deviating from this working distance are determined.

[0021] Defining the working distance of the objective lens as the reference point, the positions deviating from the working distance of the objective lens include 2n + 1, and the states of the micromirror array include 2n + 1. The 2n + 1 states of the micromirror array correspond one-to-one with the 2n + 1 positions deviating from the working distance of the objective lens. That is, there are 2n + 1 positions where the focusing position deviates from the working distance L of the objective lens, L = {L0, L1,..., L n ,..., L 2n}. When this is the case, the state S of the micromirror array also corresponds to 2n + 1 states, S = {S0, S1,..., S n ,..., S 2n}. Among them, the position of the maximum positive defocus L0 corresponds to the micromirror state S0; the focusing position L n corresponds to the micromirror state S n， and L n = 0; the position of the maximum negative defocus L 2n corresponds to the state S 2n .

[0022] Exemplarily, in this embodiment, 5 positions deviating from the working distance of the objective lens are selected. Assuming the working distance of the objective lens as the reference point, positive defocus means the object is above the reference point, and negative defocus means the object is below the reference point. The 5 positions deviating from the working distance of the objective lens selected are L0, L1, L2, L3, and L4.

[0023] L0 = +20 μm, L0 is the maximum positive defocus, and L0 is the position where the object is 20 μm above the reference point.

[0024] L1 = +10 μm, and L1 is the position where the object is 10 μm above the reference point.

[0025] L2 = 0 μm, L2 is the focusing position, that is, the working distance of the objective lens.

[0026] L3 = -10 μm, and L3 is the position where the object is 10 μm below the reference point.

[0027] L4 = -20 μm. L4 is the maximum negative defocus. L4 means the measured object is 20 μm below the reference point.

[0028] Exemplarily, in this embodiment, when collecting the microlens array states of the microlens array zoom module corresponding to each deviation from the objective working distance for the calibration object, a standard calibration object is used, such as a test pattern with clear texture. It is sequentially placed at the above-mentioned 5 positions deviating from the objective working distance, and then by adjusting the state of the microlens array to make the imaging reach the best clarity, the microlens array states corresponding to each position are recorded.

[0029] Exemplarily, in this embodiment, the microlens array state of the microlens array zoom module can be described by parameters such as the curvature and tilt angle of each microlens. For simplicity, it is assumed that the microlens array state of each microlens array zoom module is represented by a simple curvature value.

[0030] When the calibration object is at L0 = +20 μm, by continuously adjusting the curvature of each microlens in the microlens array, the test pattern captured by the microscope is made the clearest. At this time, the curvature value of the microlens array is recorded as S0 = 0.8 (the curvature value here is a relative value, only for illustrative purposes).

[0031] When the calibration object is at L1 = +10 μm, using the same method, the microlens array is adjusted to make the imaging clear, and the curvature value of the microlens array is recorded as S1 = 0.4.

[0032] When the calibration object is at L2 = 0 μm, which is the focusing position, the microlens array is adjusted to obtain the clearest imaging, and the curvature value of the microlens array is recorded as S2 = 0 (indicating that the microlens array is in a reference state without additional curvature adjustment).

[0033] When the calibration object is at L3 = -10 μm: After adjustment, the curvature value of the microlens array is recorded as S3 = -0.4.

[0034] When the calibration object is at L4 = -20 μm: After adjustment, the curvature value of the microlens array is recorded as S4 = -0.8.

[0035] In this embodiment, the obtained deviation from the objective working distance and the corresponding microlens array states of the microlens array zoom module are organized into a table to obtain a mapping relationship table between the deviation from the objective working distance and the microlens array state. The mapping relationship table is as follows:

[0036] In this embodiment, in step S102, asFigure 2 As shown in the imaging system of the microlens array zoom module, a laser spot camera 12 is used to collect the laser spot image formed by the laser irradiating the object to be measured. Since the laser spot emitted by the detection laser light source 11 passes through the first beam splitter 15, the laser is reflected in the direction of the measurement object and irradiates the surface of the measurement object after passing through the second beam splitter 16. After the object surface reflects the laser spot, the light is reflected by the second beam splitter 16 into the laser spot camera 12.

[0037] Among them, the principle of the laser focal plane detection technology is as Figure 3 shown. After the laser spot passes through the objective lens, it irradiates the surface of the object to be measured. In this process, the measured surface and the laser focusing plane will present three different relative states: when the measured surface is above the focusing plane, this situation is called positive defocus; if the measured surface coincides exactly with the focusing plane, it is the focusing state; and when the measured surface is below the focusing plane, it is negative defocus. When a semi-circular laser beam is used, different relative states of the measured surface and the focusing plane correspond to different laser spot shapes. In the case of positive defocus, the spot is a right semi-circle; when focused, the spot is a small dot; in the case of negative defocus, the spot is a left semi-circle. It should be noted that there is a linear relationship between the spot radius and the defocus amount, and the larger the radius, the larger the defocus amount. Based on this, the imaging sensor only needs to detect the shape and size of the spot to accurately judge the position of the measured surface relative to the focusing plane, that is, the direction and distance.

[0038] In this embodiment, obtaining the laser spot image formed by the laser irradiating the object to be measured and calculating the position of the object to be measured relative to the focal plane of the objective lens based on the laser spot image includes: obtaining the laser spot image formed by the laser irradiating the object to be measured, separating the spot in the laser spot image from the background to obtain a spot region image; removing the noise of the spot region image through erosion and dilation to obtain a processed spot region image; extracting the spot contour based on the processed spot region image; calculating the edge gradient of the spot based on the extracted spot contour, and determining the semi-circle direction and radius of the spot according to the calculated edge gradient of the spot; obtaining the relative position of the object to the focal plane based on the semi-circle direction and radius of the spot and the pre-calibrated mapping relationship between the radius and the defocus amount.

[0039] In this embodiment, the spot is separated from the background by means of threshold segmentation, difference method, etc. to obtain a spot region image.

[0040] In this embodiment, the spot boundary is obtained through algorithms such as Canny edge detection and contour tracking.

[0041] In this embodiment, when the laser spot (such as a Gaussian beam or a circular spot) is defocused, it may present an elliptical or semi-circular shape (depending on the optical path design). The deformation direction of the spot (such as the major axis direction) is judged by the gradient direction, and the defocus amount is calculated in combination with the radius. For example, in the laser triangulation method, the larger the defocus amount, the larger the projection size of the spot on the detector. Through calibration, a linear mapping relationship between the radius and the defocus amount can be established (such as r = 5 pixels corresponding to +10 μm), and the relative position d of the object with respect to the focal plane is obtained.

[0042] For example: If a right semi-circular spot is detected and the radius corresponds to d = +15 μm, then the object is 15 μm above the focal plane.

[0043] In this embodiment, in step S103, based on the position of the object to be measured relative to the focal plane of the objective lens, the adjustment reference distance of the microlens array zoom module is determined, and the adjustment reference distance is compared with the mapping relationship table to determine the state of the microlens array of the microlens array zoom module. Specifically, it includes: calculating the absolute value of the difference between the position of the measured object relative to the focal plane of the objective lens and multiple deviations from the working distance of the objective lens respectively; using the deviation from the working distance of the objective lens corresponding to the smallest absolute value as the adjustment reference distance; comparing the adjustment reference distance with the mapping relationship table to determine the state of the microlens array of the microlens array zoom module.

[0044] In this embodiment, the absolute difference is calculated: for each calibration distance L i , calculate R i =∣d - L i ∣.

[0045] Example: If d = +15 μm and the calibration distances are -20 μm, -10 μm, 0 μm, +10 μm, +20 μm, then: R0 = 5 μm, R1 = 5 μm, R2 = 15 μm, R3 = 25 μm, R4 = 35 μm.

[0046] If there are multiple same minimum values (such as R0 = R1 = 5 μm), the historical adjacent state is preferably selected (such as selecting L1 = +10 μm to avoid curvature jumps).

[0047] Finally, the state of the microlens array is obtained from the mapping relationship table according to L1 (such as L1 = +10 μm → S1 = 0.4).

[0048] In this embodiment, in step S104, a focusing instruction is generated based on the determined state of the microlens array, that is, the state of the microlens array of the microlens array zoom module (such as the curvature values of each micromirror) is converted into an electrical signal and sent to the MEMS controller. The MEMS controller independently adjusts the tilt angle or curvature of each micromirror so that the entire array fits into a corresponding curved surface (such as an upward bending curvature of 0.4). The MEMS drive response speed reaches 12 KHz, and the single focusing time is about 83 μs, which is much faster than traditional mechanical zoom (in the order of hundreds of milliseconds).

[0049] In this embodiment, by pre - constructing a mapping relationship table between the deviation from the working distance of the objective lens and the state of the microlens array of the microlens array zoom module, combining with the laser focal plane detection technology to obtain the object focal plane position in real - time, quickly matching the optimal micromirror state through numerical calculation, and then using the MEMS controller to realize the adjustment of the microlens array zoom module. Without mechanical moving parts, it has the advantages of extremely fast focusing speed, compact and reliable structure, high precision and strong fault tolerance. At the same time, relying on the discretization calibration and look - up table mechanism to reduce the calculation complexity, it can be flexibly adapted to different scenarios, and has great application prospects for the autofocus and high - definition imaging of complex - shaped and deformed objects.

[0050] The embodiment of the present invention also provides a zoom imaging system for a microlens array zoom module 21, including a focal plane measurement unit 10, a zoom imaging unit 20, a processor 30, and a MEMS controller 40. The focal plane measurement unit 10 is connected to the processor 30, and the MEMS controller 40 is respectively connected to the processor 30 and the microlens array zoom module 21 of the zoom imaging unit 20. The focal plane measurement unit 10 is used to collect the laser spot image formed by the laser irradiating the object 50 to be measured, and transmit the laser spot image to the processor 30. The processor 30 is used to execute the zoom method of the microlens array zoom module 21 as described above. The MEMS controller 40 is used to receive the focusing instruction and adjust the state of the microlens array of the microlens array zoom module 21 according to the focusing instruction to realize the automatic zoom of the microlens array zoom module 21.

[0051] In this embodiment, the focal plane measurement unit 10 includes a detection laser light source 11, a laser spot camera 12, a first lens 13, a second lens 14, a first beam splitter 15, a second beam splitter 16, and an objective lens 17. The detection laser light source 11 emits a laser spot, which passes through the first lens 13 and the first beam splitter 15. The first beam splitter 15 reflects the laser spot in the direction of the object 50 to be measured, and after passing through the second beam splitter 16 and the objective lens 17, irradiates the surface of the object 50 to be measured. The laser spot reflected light is formed on the surface of the object 50 to be measured. After the laser spot reflected light passes through the objective lens 17 and is reflected by the second beam splitter 16, it enters the second laser spot camera 12 through the second lens 14.

[0052] In this embodiment, the zoom imaging unit 20 includes a microlens array zoom module 21, an imaging camera 22, a coaxial light source 23, a third beam splitter 24, a fourth beam splitter 25, a third lens 26, a fourth lens 27, and a filter 28. The coaxial light source 23 emits coaxial illumination light. The coaxial illumination light passes through the third lens 26 and the third beam splitter 24. After the third beam splitter 24 directs the coaxial illumination light towards the direction of the object 50 to be measured, it passes through the filter 28, the first beam splitter 15, the second beam splitter 16, and the objective lens 17 and irradiates the surface of the object 50 to be measured. A coaxial illumination light reflected ray is formed on the surface of the object 50 to be measured. After the coaxial illumination light reflected ray passes through the objective lens 17, the second beam splitter 16, the first beam splitter 15, the filter 28, the third beam splitter 24, and the fourth beam splitter 25, it forms an imaging reflected ray after being focused and reflected by the microlens array zoom module 21. The imaging reflected ray irradiates the fourth beam splitter 25. The fourth beam splitter 25 reflects the imaging reflected ray and passes it through the fourth lens 27 into the imaging camera 22.

[0053] In this embodiment, after the micro-mirror array of the microlens array zoom module 21 is adjusted to the focused state, the objective lens 17 and the microlens array zoom module 21 cooperate to focus the object light on the photosensitive surface of the imaging camera 22 to capture a clear image.

[0054] In this embodiment, by pre-constructing a mapping relationship table between the working distance deviating from the objective lens 17 and the state of the micro-mirror array of the microlens array zoom module 21, combining with the laser focal plane detection technology to obtain the object focal plane position in real time, quickly matching the optimal micro-mirror state through numerical calculation, and then using the MEMS controller 40 to adjust the microlens array zoom module 21. Finally, without mechanical moving parts, it has the advantages of extremely fast focusing speed, compact and reliable structure, high precision, and strong fault tolerance. At the same time, relying on the discretized calibration and look-up table mechanism to reduce the calculation complexity, it can be flexibly adapted to different scenarios, and has great application prospects for automatic focusing and high-definition imaging of complex shapes and deformed objects.

[0055] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention. Any equivalent structural transformation made using the description and drawings of the present invention under the inventive concept of the present invention, or direct / indirect application in other related technical fields, is included in the patent protection scope of the present invention.

Claims

1. A zoom method for a microlens array zoom module, characterized in that Including: Obtain a mapping relationship table regarding the deviation from the working distance of the objective lens and the status of the microlens array of the microlens array zoom module; Obtain a laser spot image formed by laser irradiating the object to be measured, and based on the laser spot image, calculate the position of the object to be measured to the focal plane of the objective lens; Determine the adjustment reference distance of the microlens array zoom module based on the position of the object to be measured to the focal plane of the objective lens, and compare the adjustment reference distance with the mapping relationship table to determine the status of the microlens array of the microlens array zoom module; Generate a focusing instruction based on the determined status of the microlens array to achieve automatic zooming of the microlens array zoom module.

2. The zoom method of the microlens array zoom module according to claim 1, wherein Define the working distance of the objective lens as the reference point, then there are 2n + 1 positions deviating from the working distance of the objective lens, and there are 2n + 1 statuses of the microlens array. The 2n + 1 statuses of the microlens array correspond to the 2n + 1 deviations from the working distance of the objective lens one by one.

3. The zoom method of the microlens array zoom module according to claim 1, wherein The obtaining of the laser spot image formed by laser irradiating the object to be measured, and based on the laser spot image, calculating the position of the object to be measured to the focal plane of the objective lens includes: Obtain a laser spot image formed by laser irradiating the object to be measured, and separate the spot in the laser spot image from the background to obtain a spot region image; Remove the noise of the spot region image through erosion and dilation to obtain a processed spot region image; Extract the spot contour based on the processed spot region image; Calculate the spot edge gradient based on the extracted spot contour, and determine the semi-circular direction and radius of the spot according to the calculated spot edge gradient; Based on the semi-circular direction and radius of the spot and the pre-calibrated linear mapping relationship between the radius and the defocus amount, obtain the relative position of the object to the focal plane.

4. The zoom method of the microlens array zoom module according to claim 1, characterized in that, The determining of the adjustment reference distance of the microlens array zoom module based on the position of the object to be measured to the focal plane of the objective lens, and comparing the adjustment reference distance with the mapping relationship table to determine the status of the microlens array of the microlens array zoom module includes: Calculate the absolute values of the differences between the position of the measured object to the focal plane of the objective lens and multiple deviations from the working distance of the objective lens respectively; Use the deviation from the working distance corresponding to the smallest absolute value as the adjustment reference distance; Compare the adjustment reference distance with the mapping relationship table to determine the status of the microlens array of the microlens array zoom module.

5. The zoom method of the microlens array zoom module according to claim 1, characterized in that The generating of a focusing instruction based on the determined status of the microlens array, and sending the focusing instruction to the MEMS controller to adjust the status of the microlens array of the microlens array zoom module through the MEMS controller to achieve automatic zooming of the microlens array zoom module includes: Convert the determined status of the microlens array into an electrical signal, and generate a focusing instruction according to the electrical signal; Send the focusing instruction to the MEMS controller to adjust the status of the microlens array of the microlens array zoom module through the MEMS controller to achieve automatic zooming of the microlens array zoom module.

6. A zoom imaging system for a microlens array zoom module, characterized in that, It includes a focal plane measurement unit, a zoom imaging unit, a processor, and a MEMS controller. The focal plane measurement unit is connected to the processor. The MEMS controller is respectively connected to the processor and the microlens array zoom module of the zoom imaging unit. The focal plane measurement unit is used to collect the laser spot image formed by laser irradiating the object to be measured and transmit the laser spot image to the processor. The processor is used to execute the zoom method of the microlens array zoom module as described in any one of claims 1-5. The MEMS controller is used to receive the focusing instruction and adjust the state of the microlens array of the microlens array zoom module according to the focusing instruction to achieve automatic zoom of the microlens array zoom module.

7. The zoom imaging system of the microlens array zoom module according to claim 6, characterized in that, The focal plane measurement unit includes a detection laser light source, a laser spot camera, a first lens, a second lens, a first beam splitter, a second beam splitter, and an objective lens. The detection laser light source emits a laser spot. After passing through the first lens and the first beam splitter, the first beam splitter reflects the laser spot in the direction of the object to be measured. After passing through the second beam splitter and the objective lens, it irradiates the surface of the object to be measured. The laser spot reflected light is formed on the surface of the object to be measured. The laser spot reflected light passes through the objective lens, is reflected by the second beam splitter, and then enters the laser spot camera through the second lens. The laser spot camera is connected to the processor.

8. The zoom imaging system of the microlens array zoom module according to claim 7, characterized in that, The zoom imaging unit includes a microlens array zoom module, an imaging camera, a coaxial light source, and a third beam splitter, a fourth beam splitter, a third lens, a fourth lens, and a filter. The coaxial light source emits coaxial illumination light. The coaxial illumination light passes through the third lens and the third beam splitter. The third beam splitter directs the coaxial illumination light in the direction of the object to be measured. After passing through the filter, the first beam splitter, the second beam splitter, and the objective lens, it irradiates the surface of the object to be measured. The coaxial illumination light reflected light is formed on the surface of the object to be measured. The coaxial illumination light reflected light passes through the objective lens, the second beam splitter, the first beam splitter, the filter, the third beam splitter, and the fourth beam splitter, and then forms an imaging reflected light after being focused and reflected by the microlens array zoom module. The imaging reflected light irradiates the fourth beam splitter. The fourth beam splitter reflects the imaging reflected light and enters the imaging camera through the fourth lens.

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