Active alignment method and active alignment equipment of zoom camera module

Abstract

The invention provides an active alignment method and active alignment equipment of a zoom camera module. The method comprises the following steps: sequentially adjusting optical centers of the zoom camera module in a plurality of focal lengths to obtain coordinates of the optical centers of the plurality of focal lengths; and taking the coordinate of the reference optical center as a target optical center coordinate of the zoom camera module, and acquiring SFR values of the zoom camera module in different focal segments under the target optical center coordinate to obtain a group of initial SFR values. And calculating an adjustment scheme of the zoom camera module according to the group of initial SFR values, wherein the adjustment scheme is a relative position adjustment amount between a lens and a sensor. And adjusting the zoom camera module according to the adjustment scheme, and re-acquiring the SFR values of the zoom camera module in different focal lengths to obtain a group of calibration SFR values. And judging whether the lens and the sensor are aligned or not according to the set of calibration SFR values. When it is judged that the lens and the sensor are aligned, the position relation between the lens and the sensor is fixed.

Description

Technical Field

[0001] This application relates to the fields of optical precision manufacturing and automation technology, and in particular to an active alignment method and active alignment device for a zoom camera module. Background Technology

[0002] Zoom camera modules are commonly used in drones. In existing zoom camera modules, the lens and sensor assembly process employs the Active Alignment (AA) method, common in fixed-focus zoom camera modules. Lens and sensor alignment is crucial for ensuring optimal performance. However, the existing AA method for fixed-focus zoom camera modules determines the relative position and orientation of the lens and sensor based on their defocus curves, but it can only achieve an optimal position and orientation for one relative relationship.

[0003] However, zoom modules are continuous optical zoom modules with multiple focal lengths such as telephoto, wide, and mid-range. If the AA method of a fixed focal length zoom module is used, the relative position and orientation of the lens and sensor can be optimized at a certain focal length. However, other focal lengths may have excessive deviations or defects. This will lead to a decrease in the performance of the zoom module and thus increase the failure rate of the zoom module. Summary of the Invention

[0004] This application provides an active alignment method and active alignment device for a zoom camera module, which enables the zoom camera module to have better optical performance at various focal lengths.

[0005] In a first aspect, an active alignment method for a zoom camera module is provided for aligning the lens and sensor within the zoom camera module. The zoom camera module includes multiple focal lengths of varying sizes. The active alignment method comprises: sequentially adjusting the optical center of the zoom camera module at the multiple focal lengths to obtain the coordinates of the optical centers of the multiple focal lengths; using the coordinates of a reference optical center as the coordinates of the target optical center of the zoom camera module, and obtaining a set of initial SFR values ​​by acquiring the SFR values ​​of the zoom camera module at different focal lengths under the coordinates of the target optical center; calculating an adjustment scheme for the zoom camera module based on the set of initial SFR values, wherein the adjustment scheme is the relative position adjustment amount between the lens and the sensor; adjusting the zoom camera module according to the adjustment scheme, and re-acquiring the SFR values ​​of the zoom camera module at different focal lengths to obtain a set of calibration SFR values; determining whether the lens and the sensor are aligned based on the set of calibration SFR values; and fixing the positional relationship between the lens and the sensor when it is determined that the lens and the sensor are aligned.

[0006] Optionally, before determining the coordinates of the reference optical center, the active alignment method of the zoom camera module further includes: calculating the difference between the coordinates of the optical centers of every two focal lengths to obtain multiple optical center differences; determining whether all of the multiple optical center differences are less than a preset threshold; if all of the multiple optical center differences are less than the preset threshold, determining the coordinates of the reference optical center based on the coordinates of the optical centers of the multiple focal lengths; if any coordinate difference is greater than or equal to the preset threshold, then determining that the zoom camera module is unqualified and the process ends.

[0007] Optionally, determining the coordinates of the reference optical center based on the coordinates of the plurality of focal length optical centers specifically includes: constructing a polygon with the coordinates of the plurality of focal length optical centers as vertices; calculating the coordinates of the polygon that have the smallest distance to each vertex, and determining the coordinates of the polygon that have the smallest distance to each vertex as the coordinates of the reference optical center.

[0008] Optionally, the zoom camera module includes at least three focal lengths.

[0009] Optionally, sequentially adjusting the optical center of the zoom camera module at the multiple focal lengths specifically includes: driving the lens to translate or rotate relative to the sensor to align the lens and the sensor; or driving the sensor to translate or rotate relative to the lens to align the lens and the sensor.

[0010] Optionally, the step of sequentially adjusting the optical center of the zoom camera module under the multiple focal lengths further includes: acquiring an image of the test target at the current relative position of the lens and the sensor; and determining whether the lens and the sensor are aligned based on whether the center of the test target is located at the center of the image.

[0011] Optionally, determining whether the lens and the sensor are aligned based on the set of calibration SFR values ​​specifically includes: comparing each SFR value in the set of calibration SFR values ​​with a preset SFR value; if each SFR value in the set of calibration SFR values ​​is greater than or equal to the preset SFR value, then the lens and the sensor are aligned; if any SFR value in the set of calibration SFR values ​​is less than the preset SFR value, then the lens and the sensor are not aligned.

[0012] Optionally, the active alignment method for the zoom camera module further includes: when it is determined that the lens and the sensor are not aligned, calculating an adjustment scheme for the zoom camera module based on the current set of calibration SFR values ​​to obtain a new adjustment scheme; re-acquiring the SFR values ​​of the zoom camera module at different focal lengths based on the new adjustment scheme to obtain a new set of calibration SFR values; re-determining whether the lens and the sensor are aligned based on the new set of calibration SFR values; when the lens and the sensor are aligned, fixing the positional relationship between the lens and the sensor; or determining that the zoom camera module is unqualified until the new adjustment scheme has reached a preset number of times and the lens and the sensor are still not aligned.

[0013] Optionally, the specific steps for obtaining the SFR values ​​of the zoom camera module at different focal lengths include: obtaining multiple calibration images from images captured by the zoom camera module at different focal lengths; obtaining the SFR values ​​of each calibration image in the image center and four corner regions to obtain the SFR values ​​at different focal lengths; wherein, calculating the adjustment scheme of the zoom camera module based on the initial set of SFR values ​​or calculating the adjustment scheme of the zoom camera module based on the current set of calibration SFR values ​​to obtain a new adjustment scheme specifically includes: adding the SFR values ​​of each calibration image at the image center to obtain the center SFR value; adding the SFR values ​​of each calibration image at each corner to obtain the corner SFR value; determining the horizontal translation amount and the vertical translation amount based on the center SFR value and the corner SFR values ​​respectively, wherein the horizontal translation amount represents adjusting the translation amount of the lens or sensor in the horizontal direction, and the vertical translation amount represents adjusting the translation amount of the lens or sensor in the vertical direction.

[0014] Secondly, embodiments of this application provide an active alignment device, which includes a memory and a processor. The memory is used to store a computer program, and the processor is used to execute the computer program to implement the above-described active alignment method for a zoom camera module.

[0015] The aforementioned active alignment method for zoom camera modules introduces a global alignment benchmark—a reference optical center—and uses multi-focal-length, multi-region SFR (Spatial Frequency Response) data as feedback. This achieves systematic optimization of the overall imaging performance of the zoom camera module across all target focal lengths. This method overcomes the inherent limitations of traditional single-point alignment, which only optimizes a single focal length. It ensures that after alignment, the lens and sensor achieve and maintain a high level of imaging quality across the entire focal length range. This significantly reduces the defect rate caused by performance imbalances across focal lengths, improving the overall production yield and product performance consistency of zoom camera modules. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0017] Figure 1 This is a flowchart of an active alignment method for a zoom camera module provided in an embodiment of this application.

[0018] Figure 2 This is a schematic diagram of an active alignment device provided in an embodiment of this application.

[0019] Figure 3 This is a predetermined region map of the calibration image provided in the embodiments of this application.

[0020] Figure 4 A set of SFR value tables is provided for embodiments of this application.

[0021] Figure 5 The first sub-flowchart of step S102 provided in the embodiments of this application.

[0022] Figure 6 A schematic diagram illustrating the principle of coordinate calculation for the reference optical center provided in the first embodiment of this application.

[0023] Figure 7 A schematic diagram illustrating the principle of coordinate calculation for the reference optical center provided in the second embodiment of this application.

[0024] Figure 8 The iterative optimization alignment flowchart provided for the embodiments of this application.

[0025] Figure 9 This is a schematic diagram of another active alignment device structure provided in an embodiment of this application.

[0026] Explanation of the numbers in the diagram: 100-Active alignment device; 110-Main control device; 111-Drive device; 112-Backlight source; 113-Test target board; 901-Memory; 902-Processor; 903-Bus; 904-Display component; 905-Communication component.

[0027] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0028] 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. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0029] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification, claims, and accompanying drawings of this application are used to distinguish similar planned objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data are interchangeable where appropriate; in other words, the described embodiments are implemented according to a sequence other than that illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, may also include other content; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0030] It should be noted that the use of terms such as "first" and "second" in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of a person skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0031] Please refer to the following: Figure 1 and Figure 2 This document presents a flowchart of an active alignment method for a zoom camera module, as provided in an embodiment of this application. The zoom camera module includes a lens and a sensor. The active alignment method for the zoom camera module is applied during the production process of an optical lens zoom camera module to center-align the lens and sensor. The active alignment device 100 includes a main control device 110, a drive device 111, a backlight source 112, and a test target 113. The main control device 110 serves as the control core, responsible for running the algorithm flow of the active alignment method for the zoom camera module. The drive device 111, as the actuator, is directly mechanically coupled to the lens or sensor, receiving alignment commands from the main control device 110 and driving the lens relative to the sensor or the sensor relative to the lens, thereby physically changing their relative position and orientation. The backlight source 112 provides highly uniform and stable illumination, ensuring that the pattern on the test target 113 is clearly and uniformly imaged onto the sensor, laying a high-quality image data foundation for acquiring test images for calculation and analysis. The test target plate 113 is engraved with specific high-contrast feature patterns (such as a dot array or a cross grid) as a fixed spatial reference. The test image generated by the feature patterns on the sensor is the basis for the main control device 110 to perform calculations and generate alignment commands. These components work together to form the hardware foundation for realizing the active alignment method.

[0032] Specifically, the active alignment method for the zoom camera module includes the following steps.

[0033] Step S101: Sequentially adjust the optical center of the zoom camera module at multiple focal lengths to obtain the coordinates of the optical center at multiple focal lengths.

[0034] Specifically, the zoom camera module to be assembled is installed on the worktable of the active alignment device 100. The lens and sensor are installed in preset positions on the worktable according to a preset relative relationship, completing the initial assembly. Then, the optical centers at multiple focal lengths are sequentially adjusted. In this embodiment, the multiple focal lengths include a first focal length, a second focal length, and a third focal length. The first focal length is the telephoto range, the second is the mid-range, and the third is the wide-angle range. The telephoto range is typically most sensitive to optical alignment errors; even slight deviations can lead to a significant decrease in image quality. The mid-range is usually the most frequently used focal length, and its image quality significantly impacts overall performance. The wide-angle range reflects the imaging characteristics of a wide-angle view and is particularly prone to edge aberrations and distortion. By covering these three typical focal lengths, the optical consistency of the zoom camera module across the entire zoom range can be comprehensively evaluated, thereby ensuring that the zoom camera module meets imaging specifications at each focal length.

[0035] Obtaining the optical center corresponding to each focal length includes the following steps: First, the main control device 110 issues a command to control the zoom motor integrated in the drive device 111 to drive the internal lens group of the lens to move, so that the zoom camera switches to the first focal length. In this focal length, the main control device 110 adjusts the relative position between the lens and the sensor in real time by performing one of the following two adjustment methods through the drive device 111 according to a preset algorithm: driving the lens to translate or rotate relative to the sensor to align the lens and the sensor; or driving the sensor to translate or rotate relative to the lens to align the lens and the sensor.

[0036] Furthermore, during the aforementioned adjustment process, the main control device 110 needs to sequentially perform the following key operations to determine whether alignment is achieved: acquiring an image of the test target at the current relative position of the lens and sensor; determining whether the lens and sensor are aligned based on whether the center of the test target is located at the center of the image. Specifically, during the adjustment process, the backlight source 112 provides uniform illumination to the test target 113. The main control device 110 synchronously receives the image generated on the test target 113 by the sensor and, based on the built-in image processing and positioning algorithm, analyzes whether the center of the test target in the image coincides with the center of the image, thereby accurately assessing whether the lens and sensor are aligned at this focal length. A closed-loop feedback is constructed based on the judgment result within the main control device 110. The main control device 110 cyclically issues adjustment commands, which are executed by the drive device 111. Subsequently, the image acquisition and analysis judgment steps are repeated until the optimal relative position for image alignment is found at the first focal length. At this point, the optical center position of the lens at the first focal length is determined, and the main control device 110 records its coordinates. Subsequently, the main control device 110 controls the lens to move sequentially to other target focal lengths such as the second focal length and the third focal length. Under each focal length, the closed-loop process of adjustment performed by the drive device 111, imaging through the test target plate 113 and the backlight source 112, and image analysis, center judgment and coordinate recording completed by the main control device 110 is completely repeated, thereby obtaining the optical center coordinates corresponding to all target focal lengths.

[0037] Step S102: Use the coordinates of the reference optical center as the coordinates of the target optical center of the zoom camera module, and obtain a set of initial SFR values ​​by acquiring the SFR values ​​of the zoom camera module at different focal lengths under the coordinates of the target optical center.

[0038] Specifically, after acquiring the optical center coordinates of the zoom camera module at multiple characteristic focal lengths, this step aims to establish a unified and optimal optical reference point for the entire zoom camera module, i.e., the coordinates of the reference optical center. Unlike the traditional fixed-focal-length zoom camera module alignment method that optimizes only a single working point, the zoom camera module must ensure good imaging performance throughout the entire continuous zoom range. Due to factors such as lens eccentricity, motor stroke nonlinearity, and structural tolerances, the actual position coordinates of the optical center on the sensor image plane at different focal lengths usually do not coincide. If the optical center coordinates of a certain focal length are simply used as the global alignment reference, it may lead to a significant decrease in the imaging quality of other focal lengths, such as resolution or eccentricity. This is the main reason for the low yield when traditional alignment methods are applied to zoom camera modules.

[0039] Therefore, this step proposes and implements the concept of the coordinates of the reference optical center. This coordinate is a single coordinate point derived from the optical center coordinate data of each focal length using a specific algorithm, such as geometric optimization. It is not simply equivalent to the actual optical center coordinates of any single focal length, but rather serves as a global compromise and optimization benchmark. When the lens and sensor make the final tilt angle adjustment with this coordinate as a reference, it can maximize the imaging performance of all target focal lengths simultaneously, thereby pursuing optimal performance of the entire zoom camera module, rather than merely achieving local optimization for a single focal length. The SFR values ​​obtained under this benchmark at different focal lengths constitute the aforementioned set of initial SFR values, which will serve as the initial state and judgment basis for subsequent iterative adjustments.

[0040] Obtaining the initial SFR values ​​for this set includes the following steps: First, under the reference optical center coordinates, the zoom camera module is controlled to sequentially switch to each target focal length and acquire images of the corresponding test target 113, thereby obtaining multiple calibration images. Then, according to pre-set division rules, multiple predetermined areas to be evaluated are determined on each calibration image. For example... Figure 3 As shown, these regions include at least the center region located at the geometric center of the image, and four corner regions located at the top left (LT), top right (RT), bottom left (LB), and bottom right (RB) of the image, respectively. The center region is used to evaluate the baseline imaging performance near the lens optical axis; the four corner regions are extremely sensitive to minute tilt or bending errors during imaging, making them key observation points for diagnosing attitude deviations between the lens and the sensor.

[0041] After selecting the predetermined regions, the spatial frequency response (SFR) value is calculated for each predetermined region in each calibration image. The SFR value is a key quantitative indicator used to objectively evaluate the resolution and contrast retention level of an imaging system in a specific region and at a specific spatial frequency. The SFR value calculation process is as follows: First, the edge image data of the test pattern is extracted from the region; then, its edge spread function is analyzed, and mathematical processing such as Fourier transform is performed; finally, a scalar value between 0 and 1 is output. A higher SFR value indicates a sharper and clearer image in the corresponding region. This step iterates through each predetermined region in every calibration image at all focal lengths, ultimately generating a complete dataset containing the SFR value corresponding to each focal length and each predetermined region. In this embodiment, as... Figure 4 As shown, the above calculation covers three focal lengths (Wide, Mid-Range, Wide) and five image regions (Center, LT, RT, LB, RB), thereby generating a dataset containing fifteen independent SFR values, which fully quantifies the sharpness distribution of the zoom camera module at different focal lengths and different positions in the image.

[0042] Step S103: Calculate the adjustment scheme of the zoom camera module based on a set of initial SFR values. The adjustment scheme is the adjustment amount of the relative position between the lens and the sensor.

[0043] The main control device 110 analyzes and calculates the initial SFR values ​​to provide a quantitative basis for subsequent adjustments. The calculation of the adjustment scheme includes a comprehensive judgment of translation and tilt.

[0044] First, the translation amount is determined by summing the SRF values ​​at the center of each calibration image to obtain the center SFR value; then, the SRF values ​​at each corner of each calibration image are summed to obtain the corner SFR value. Based on the center SFR value and the corner SFR values, the horizontal and vertical translation amounts are determined. The horizontal translation amount represents the amount of horizontal adjustment of the lens or sensor. Specifically, the SFR values ​​at the center of each calibration image are summed to obtain the total center SFR value; simultaneously, the SFR values ​​at each corner (e.g., upper left, upper right, lower left, lower right) of each calibration image are summed to obtain the total corner SFR value. By comparing the differences between the total center SFR value and the total corner SFR values, the overall offset trend of the lens optical axis projection relative to the sensor's photosensitive center can be preliminarily determined, thus providing data support for determining the horizontal and vertical translation amounts of the lens or sensor.

[0045] Subsequently, the tilt amount is determined. To more accurately compensate for the relative tilt between the lens and the sensor, the main control device 110 further calculates the comprehensive evaluation value for each predetermined area. This calculation, for each predetermined area, integrates the SFR values ​​across all target focal lengths, primarily using two methods: the first is to directly sum the SFR values ​​of the area across each focal length, focusing on the global balance of performance across the entire focal length; the second is to multiply the SFR values ​​of each focal length by a preset weight, sum them, and then average them, focusing on meeting the priority performance indicators of a specific focal length. The level of the comprehensive evaluation value directly reflects the overall image sharpness of that area across all focal lengths. By comparing the comprehensive evaluation values ​​of each predetermined area, the tilt direction and degree that the lens and / or sensor need to compensate for are determined based on the comparison results, thereby generating corresponding adjustment commands. The core principle is that, according to optical imaging characteristics, the area with the lowest comprehensive evaluation value corresponds to the image point position that is most blurred and furthest from the ideal focal plane throughout the entire zoom range. By comparing the comprehensive evaluation values ​​of the central area and each corner area, the main control device 110 can accurately diagnose the tilt direction and degree of the image plane relative to the sensor plane. The image plane refers to the theoretical plane on which a sharp image is formed through the lens. Under ideal alignment, this image plane should perfectly coincide with the sensor's photosensitive plane. When the lens optical axis is not perpendicular to the sensor plane, the image plane will be tilted, resulting in inconsistent sharpness across different parts of the image.

[0046] Specifically, the main control device 110 analyzes the difference between the overall SFR value of the central region calculated from the image of the test target 113 and the overall SFR values ​​of each corner region, and runs its built-in tilt diagnosis algorithm to calculate the rotation compensation amount required to level the image plane. This rotation compensation amount is quantified as the angle Tx and the angle Ty that the lens or sensor needs to rotate around its X-axis. For example, if the diagnosis finds that only the lower right corner region has the lowest overall evaluation value, it indicates that the image plane is tilted relative to the sensor plane in a state of "near the upper left corner and far from the lower right corner." To correct this state, the adjustment algorithm in the main control device 110 will generate a set of specific spatial angle commands Tx and Ty. Tx takes a negative value, raising the right side of the lens relative to the sensor (or equivalently raising the left side of the sensor) to bring the image distance closer to the lower right corner region; Ty takes a positive value, raising the lower side of the lens relative to the sensor (or equivalently raising the upper side of the sensor), also aiming to bring the image distance closer to the lower right corner region. Subsequently, the drive unit 111, acting as an actuator, precisely receives and drives the lens or sensor to perform corresponding minute rotational movements according to this instruction. Through this targeted adjustment, the image distance in the lower right corner area can be shortened, making the lens optical axis gradually more perpendicular to the sensor plane, ultimately bringing their relative spatial orientation towards an ideal parallel state.

[0047] Step S104: Adjust the zoom camera module according to the adjustment scheme, and re-acquire the SFR values ​​of the zoom camera module at different focal lengths to obtain a set of calibrated SFR values.

[0048] Specifically, the active alignment device's actuator receives and executes the adjustment plan. Adjustment can be achieved by either rotating the lens or rotating the sensor. By executing the compensation calculated in the adjustment plan, the diagnosed tilted image plane can be gradually corrected to a position that better matches the sensor plane. This adjustment aims to improve the image sharpness of the previously out-of-focus areas while ensuring performance in other areas, thereby promoting a more uniform SFR value distribution across all target focal lengths in the entire image. After adjustment, the SFR values ​​of all areas need to be reacquired to obtain a set of calibrated SFR values ​​to verify the correction effect.

[0049] Step S105: Determine whether the lens and sensor are aligned based on a set of calibration SFR values.

[0050] Each SFR value in a set of calibrated SFR values ​​is compared one by one with a preset SFR value. Specifically, the main control device 110 first acquires the set of calibrated SFR values ​​described in step S104. Then, each SFR value in the set of calibrated SFR values ​​is compared one by one with a predefined specification threshold based on the final imaging performance requirements of the product. In this embodiment, the specification threshold is set to 0.5. It can be understood that this threshold can be adjusted according to the specific optical design specifications of different products, and its core purpose is to provide an objective, unified, and quantitative judgment benchmark for determining whether the lens and sensor are aligned.

[0051] If every SFR value in a set of calibration SFR values ​​is greater than or equal to a preset SFR value, the control unit determines that the relative position of the lens and sensor meets the requirements, that is, it determines that the lens and sensor are aligned. In this embodiment, when all SFR values ​​are greater than or equal to 0.5, it is determined that the lens and sensor are aligned.

[0052] If any SFR value in a set of calibration SFR values ​​is less than a preset SFR value, the control unit determines that the current relative position fails to meet the requirements, i.e., the lens and sensor are misaligned. In this embodiment, when any SFR value is less than 0.5, the lens and sensor are determined to be misaligned.

[0053] Step S106: When it is determined that the lens and sensor are aligned, the positional relationship between the lens and sensor is fixed.

[0054] The zoom camera module is deemed to have met the imaging performance requirements for the entire focal length and field of view only when the main control device 110 confirms the alignment of the lens and sensor based on the verification results in step S105. At this time, the main control device 110 issues a command to initiate the final physical curing process. Specifically, this process is precisely controlled by the main control device 110, and the high-precision dispensing mechanism integrated in the drive device 111 applies a fixed amount of ultraviolet curing adhesive to the preset key mechanical coupling points between the lens barrel and the sensor base. Subsequently, the UV curing light source integrated in the drive device 111 is immediately triggered to irradiate the adhesive-coated area. The adhesive cures rapidly under ultraviolet light excitation, thereby permanently fixing the overall optimized relative spatial position between the lens and the sensor. Thus, the active alignment and assembly process of a zoom camera module is completed.

[0055] In steps S101 to S106 above, this application provides an active alignment method for zoom camera modules. This method allows the active alignment device to simultaneously measure and optimize the imaging performance at multiple focal lengths during the assembly of the zoom camera module, ultimately determining a lens-sensor relative position that optimizes the overall imaging quality across the entire focal length. The method first establishes a unified global optical reference, i.e., the coordinates of the reference optical center, through multi-focal length measurements. Using these coordinates as a reference, the main control device 110 collects a set of initial SFR values ​​and calculates an adjustment scheme including tilt compensation. Subsequently, the adjustment is performed, and alignment verification is conducted based on a newly acquired set of calibrated SFR values, forming a closed-loop optimization process of measurement, analysis, adjustment, and verification. This method abandons the traditional optimization strategy targeting a single focal length. By establishing a global reference and a comprehensive evaluation value feedback mechanism across multiple focal lengths and regions, it effectively solves the problem of maintaining alignment accuracy across all focal lengths in zoom camera modules, thereby fundamentally improving the consistency and stability of imaging quality across the entire focal length and the overall assembly yield.

[0056] Please refer to the following: Figure 5 , Figure 6 and Figure 7 This is the first sub-flowchart of step S102 provided in the embodiments of this application. Before determining the coordinates of the reference optical center, the active alignment method of the zoom camera module further includes the following steps: Step S201: Calculate the difference in optical center coordinates between every two focal lengths to obtain multiple optical center differences.

[0057] Specifically, the coordinates of the multiple optical centers calculated in step S101 are obtained, and these coordinates correspond to different focal lengths. In this embodiment, optical center point A corresponding to the telephoto focal length, point B corresponding to the mid-focal length, and point C corresponding to the near-focal length are selected. First, the differences between these points are calculated. Specifically, the differences between points A and B, between points A and C, and between points B and C are calculated respectively. These differences, expressed in units of sensor pixels, quantitatively reflect the degree of optical center offset at different focal lengths.

[0058] Step S202: Determine whether all the differences between multiple optical centers are less than a preset threshold.

[0059] Specifically, the optical center differences calculated in step S201 are compared sequentially with a preset threshold. This preset threshold is a qualification standard determined based on product design specifications, lens manufacturing tolerances, and assembly process capabilities. The purpose of this step is to screen zoom camera modules with severely inconsistent optical centers due to problems such as excessive lens element eccentricity, excessive lens barrel structural tolerances, severe cumulative assembly errors, or nonlinear zoom motor travel. In this embodiment, the preset threshold is set to 100 pixels. If all optical center differences are less than 100 pixels, it indicates that the optical center drift of the zoom camera module is within an acceptable consistency range, and the process proceeds to step S203 for further optimization calculations. If any optical center difference is greater than or equal to 100 pixels, the process jumps to step S204 to perform other operations.

[0060] Step S203: If the differences between multiple optical centers are all less than a preset threshold, determine the coordinates of the reference optical center based on the coordinates of the multiple focal length optical centers.

[0061] After step S202 determines that the differences between all optical centers are less than a preset threshold, the process proceeds to this step. This step specifically includes: constructing a polygon using the coordinates of multiple focal length optical centers as vertices; calculating the coordinates of the polygon with the minimum distance to each vertex, and determining the coordinates of the polygon with the minimum distance to each vertex as the coordinates of the reference optical center. Specifically, a polygon is constructed using the obtained coordinates of all focal length optical centers as vertices. An optimization algorithm is used to calculate the point in the polygon plane with the minimum sum of distances to all its vertices. This point is then determined as the coordinates of the reference optical center. This method seeks to minimize the sum of the squares of the overall deviations, representing a statistically optimal compromise. Therefore, the above geometric calculation method is not limited to the coordinates of three focal length optical centers and can be flexibly applied to the coordinates of any number of optical centers.

[0062] In this embodiment, for the coordinates of the optical centers at the three most common focal lengths—coordinate A for the telephoto range, coordinate B for the mid-focal range, and coordinate C for the near-focal range—an efficient geometric construction method can be used to determine the coordinates of the reference optical center. First, compare the lengths of the three sides of the triangle formed by coordinates A, B, and C, and find the longest side; here, we assume the longest side is AC. Take the midpoint of side AC, denoted as coordinate O. Connect coordinate B and coordinate O to form line segment BO. Since O is the midpoint of AC, line segments AO and CO are naturally equal. Next, calculate the ratio BO / AO.

[0063] If BO / AO < 1, such as Figure 6 As shown, the distance from coordinate B to the midpoint of AC is less than half the length of side AC. In this case, the distances from the midpoint O of AC to the three coordinates A, B, and C are relatively balanced; therefore, coordinate O can be directly determined as the coordinate of the reference optical center.

[0064] If BO / AO ≥ 1, such as Figure 7 As shown, coordinate B is far from side AC, and simply taking the midpoint of AC is not sufficient. Therefore, we need to find a point closer to coordinates A, B, and C. Move coordinate O along a perpendicular line passing through point O and perpendicular to side AC towards coordinate B. The goal is to make the new coordinate O equal to the distances to coordinates A, B, and C, i.e., AO equals BO equals CO. In practical numerical calculations, this can be achieved through iterative approximation or by directly finding the point that minimizes the sum of the distances to AO, BO, and CO. The coordinate O finally found using this method is the coordinate of the desired reference optical center.

[0065] In other embodiments, the number of coordinates selected for the focal length optical center can be two, four, or more. When two focal length optical center coordinates are selected, coordinates A and B are obtained. The most direct method for determining the coordinates O of the reference optical center in this case is to take the midpoint of line segment AB as coordinate O. This midpoint satisfies OA=OB and is the only point that minimizes the sum of distances from coordinate O to coordinates A and B, thus achieving a compromise between the optical deviations of the two focal lengths. When more than three focal length optical center coordinates are selected, the resulting coordinate set can form a quadrilateral or a more general polygon. After constructing the polygon with these coordinates as vertices, the coordinates O of the reference optical center is the point in the polygon plane with the minimum sum of distances to all its vertices. This point is called the geometric median in computational geometry and can be iteratively solved using efficient numerical optimization algorithms, thus quickly converging to the optimal solution.

[0066] In step S204, if any coordinate difference is greater than or equal to a preset threshold, the zoom camera module is determined to be unqualified, and the process ends.

[0067] If, in step S202, the distance between the coordinates of any two optical centers is found to be greater than or equal to a preset threshold, it indicates that the optical center deviation of the zoom camera module at different focal lengths is too large, exceeding the range that can be compensated for by subsequent tilt adjustments. This usually indicates an unacceptable inherent defect in the lens or zoom camera module. The zoom camera module is then determined to be a defective product. The active alignment device 100 will stop all subsequent processing of the zoom camera module and control the robotic arm or conveyor mechanism to remove it from the normal production process and place it in the defective product collection area, i.e., perform a discarding process. This step ensures that only zoom camera modules with good optical consistency can enter the subsequent time-consuming precision adjustment stage, thereby improving overall production efficiency and yield.

[0068] Through the closed-loop decision-making and calculation in steps S201 to S204 above, this application achieves effective screening of the basic quality of zoom camera modules in the early stage of assembly, and calculates a scientific and unified reference optical center coordinate for qualified zoom camera modules, laying a solid foundation for subsequent multi-focal length sharpness collaborative optimization.

[0069] Please refer to Figure 8 This is an iterative optimization alignment flowchart provided in the embodiments of this application. Specifically, the flowchart illustrates a closed-loop iterative adjustment cycle, including feedback and verification mechanisms, automatically initiated by the main control device 110 when step S105 initially determines that the lens and sensor are not aligned. The specific steps include: Step S301: When it is determined that the lens and sensor are not aligned, a new adjustment scheme is obtained by calculating the adjustment scheme of the zoom camera module based on the current set of calibration SFR values.

[0070] This step is triggered when it is determined that the lens and sensor are misaligned based on the comparison result in step S105. In this embodiment, if any calibration SFR value is less than 0.5, it is determined that the lens and sensor are misaligned. At this time, a new adjustment scheme will be obtained based on the current set of calibration SFR values.

[0071] Step S302: Based on the new adjustment scheme, re-acquire the SFR values ​​of the zoom camera module at different focal lengths to obtain a new set of calibration SFR values.

[0072] Specifically, after adjusting the zoom camera module according to the new adjustment scheme, the main control device 110 will re-acquire the SFR values ​​of the zoom camera module at different focal lengths, thereby obtaining the new set of calibrated SFR values. In this embodiment, the specific operation steps for re-acquiring the SFR values ​​are the same as the process of obtaining a set of initial SFR values ​​in the aforementioned step S102, and will not be described in detail here.

[0073] Step S303: Re-determine whether the lens and sensor are aligned based on the new set of calibration SFR values.

[0074] Specifically, after completing the adjustment in step S302, to evaluate the effect of this adjustment, a new set of calibration SFR values ​​needs to be obtained, and alignment is determined accordingly. The control unit moves the drive lens sequentially to each target focal length, re-acquires images, and recalculates the SFR values ​​for each predetermined area according to the same rules, thereby obtaining the new set of calibration SFR values. This set of data reflects the latest state of the zoom camera module after adjustment and is the direct basis for determining whether the lens and sensor are aligned. The specific logic and execution method of this determination are the same as the process of "determining whether the lens and sensor are aligned based on a set of calibration SFR values" in step S105 above, and will not be repeated here.

[0075] Step S304: Once the lens and sensor are aligned, fix the positional relationship between the lens and sensor.

[0076] Specifically, the main control device 110 determines that the lens and sensor are aligned based on a newly acquired set of calibration SFR values, indicating that the iterative adjustments have enabled the zoom camera module to meet performance specifications. The main control device 110 then issues a command to terminate the optimization loop and initiate the final physical curing process. In this process, the precision dispensing mechanism integrated into the drive device 111, precisely controlled by the main control device 110, works in conjunction with the UV curing system: the dispensing mechanism applies a fixed amount of UV-curable adhesive to the preset key mechanical coupling points between the lens and sensor; subsequently, the UV curing light source is immediately triggered, irradiating the adhesive area to cure it instantly, thereby permanently locking the verified and optimized relative positional relationship between the lens and sensor. At this point, the entire active alignment process is successfully completed.

[0077] In step S305, if the lens and sensor are not aligned, the adjustment scheme is repeated, and it is determined whether the number of repetitions has reached the preset number.

[0078] Specifically, if the master control device 110 determines that the lens and sensor are misaligned based on a new set of calibration SFR values, it indicates that the current adjustment has not completely resolved the problem. The control process will not terminate immediately but will prepare for the next iteration. Before this, the master control device 110 will query an internal counter that records the cumulative number of times the adjustment scheme has been repeated since the start of the current iteration cycle. The master control device 110 compares this cumulative number with a pre-set maximum allowed number of times. If the current number of repetitions has not yet reached the preset number, the process will return to step S302, and the adjustment scheme will be executed again based on the latest set of calibration SFR value data to start a new round of optimization.

[0079] Step S306: When the new adjustment scheme has reached the preset number of times and the lens and sensor are still not aligned, the zoom camera module is determined to be unqualified.

[0080] If, in step S306, the main control device 110 confirms that the number of repetitions has reached the preset upper limit, and the latest SFR value calculated based on the test target image 113 still has items that do not meet the standard, then the main control device 110 determines that the zoom camera module has a performance defect that cannot be corrected by a limited number of adjustments. Such defects may originate from inherent lens aberrations or hardware flaws. To eliminate invalid adjustments and ensure factory quality, the main control device 110 will forcibly terminate the optimization process and ultimately determine that the zoom camera module is a defective product. Subsequently, the main control device 110 controls the drive device 111 or other linkage mechanism to remove the zoom camera module from the production line for disposal to ensure that it does not enter subsequent stages.

[0081] Through the closed-loop feedback process of measurement, analysis, adjustment, and verification constituted by steps S301 to S306 above, this solution constructs a real-time optimization mechanism with intelligent and adaptive capabilities. This mechanism reproduces the iterative adjustment process performed by experienced engineers and achieves more efficient and stable multi-parameter balancing and optimization through algorithms. It actively guides the imaging performance of the zoom camera module to approach and meet preset specifications, thereby directly improving production yield. At the same time, by setting a clear upper limit on the number of iterations, this process ensures that production resources are not wasted on individual defective products that cannot be repaired. In addition, its fully automatic decision-making logic of fixing whether it meets the standard and rejecting it if it does not completely eliminates the inconsistency and uncertainty that may be caused by manual judgment, effectively ensuring the reliability of the performance of each zoom camera module leaving the factory and the consistency between different production batches from the process level.

[0082] Please refer to Figure 9 The active alignment device 100 also includes a memory 901 and a processor 902. The processor 902 is used to run computer program instructions in the memory 901 to implement the active alignment method of the zoom camera module.

[0083] The memory 901 includes at least one type of readable storage medium, including flash memory, hard disk, multimedia card, card-type memory (e.g., SD or DX memory), magnetic memory, magnetic disk, optical disk, etc. In some embodiments, the memory 901 can be an internal storage unit of the active alignment device, such as the hard disk of the active alignment device. In other embodiments, the memory 901 can also be an external storage device of the active alignment device, such as a plug-in hard disk, SmartMediaCard (SMC), SecureDigital (SD) card, FlashCard, etc., configured in the active alignment device. Furthermore, the memory 901 can include both internal storage units and external storage devices of the active alignment device. The memory 901 can be used not only to store application software and various types of data installed on the active alignment device, such as the code of the active alignment method of the zoom camera module, but also to temporarily store data that has been output or will be output.

[0084] Furthermore, the active alignment device 100 also includes a bus 903. Bus 903 can be a peripheral component interconnect (PCI) bus or an extended industry standard architecture (EISA) bus, etc. This bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 9 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0085] Furthermore, the active alignment device 100 may also include a display component 904. The display component 904 may be an LED display, a liquid crystal display, a touch-sensitive liquid crystal display, or an organic light-emitting diode (OLED) touchscreen, etc. The display component 904 may also be appropriately referred to as a display device or display unit, used to display information processed in the active alignment device 100 and to display a user interface for visualization.

[0086] Furthermore, the active alignment device 100 may also include a communication component 905. The communication component 905 may optionally include a wired communication component and / or a wireless communication component (such as a Wi-Fi communication component, a Bluetooth communication component, etc.), which is typically used to establish a communication connection between the active alignment device 100 and other active alignment devices.

[0087] Figure 9Only a partial alignment device 100 with a method for implementing an active alignment of a zoom camera module is shown. Those skilled in the art will understand that... Figure 9 The structure shown does not constitute a limitation on the active alignment device 100 and may include fewer or more components than shown, or combine certain components, or have different component arrangements.

[0088] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, or any combination thereof. When implemented using software, it can be implemented, in whole or in part, in the form of a computer program product.

[0089] The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the flow or function according to embodiments of the present invention is generated. The active alignment device may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium may be any available medium that a computer can store or a data storage device such as a server or data center that integrates one or more available media. The available medium may be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., a solid-state drive (SSD)).

[0090] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0091] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection between apparatuses or units through some interfaces, and may be electrical, mechanical, or other forms.

[0092] The unit described as a separate component may or may not be physically separate. The component shown as a unit may or may not be a physical unit; that is, it may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0093] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist independently, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0094] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause an active targeting device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this application. The aforementioned storage medium includes: USB flash drives, portable hard drives, read-only storage media (ROM), random access storage media (RAM), magnetic disks, optical disks, and other media capable of storing program code.

[0095] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

[0096] It should be understood that although the steps in the flowcharts of the accompanying figures are shown sequentially as indicated by the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the accompanying figures may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times, and their execution order is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the sub-steps or stages of other steps.

[0097] The above-listed embodiments are merely preferred embodiments of this application and should not be construed as limiting the scope of this application. Therefore, any equivalent variations made in accordance with the claims of this application shall still fall within the scope of this application.

Claims

1. An active alignment method for a zoom camera module, used to align the lens and sensor in the zoom camera module; The zoom camera module includes multiple focal lengths, each with a different size; its characteristic is... The active alignment method of the zoom camera module includes: The optical centers of the zoom camera module at the multiple focal lengths are sequentially adjusted to obtain the coordinates of the optical centers at the multiple focal lengths. Using the coordinates of the reference optical center as the coordinates of the target optical center of the zoom camera module, and obtaining the SFR values ​​of the zoom camera module at different focal lengths under the coordinates of the target optical center, a set of initial SFR values ​​is obtained. The adjustment scheme of the zoom camera module is calculated based on the set of initial SFR values, wherein the adjustment scheme is the relative position adjustment between the lens and the sensor. The zoom camera module is adjusted according to the adjustment scheme, and a set of calibration SFR values ​​is obtained by re-acquiring the SFR values ​​of the zoom camera module at different focal lengths. Based on the set of calibration SFR values, determine whether the lens and the sensor are aligned; When it is determined that the lens and the sensor are aligned, the positional relationship between the lens and the sensor is fixed.

2. The active alignment method for a zoom camera module as described in claim 1, characterized in that, Before determining the coordinates of the reference optical center, the active alignment method of the zoom camera module further includes: Calculate the difference in optical center coordinates between every two focal lengths to obtain multiple optical center differences; Determine whether all the differences between the multiple optical centers are less than a preset threshold; If all the differences between the plurality of optical centers are less than the preset threshold, the coordinates of the reference optical center are determined based on the coordinates of the plurality of focal length optical centers. If any coordinate difference is greater than or equal to the preset threshold, the zoom camera module is determined to be unqualified, and the process ends.

3. The active alignment method for a zoom camera module as described in claim 2, characterized in that, The step of determining the coordinates of the reference optical center based on the coordinates of the multiple focal length optical centers specifically includes: A polygon is constructed using the coordinates of the optical centers of the multiple focal lengths as vertices; Calculate the coordinates of the polygon that have the smallest distance to each vertex, and determine the coordinates of the reference optical center as the coordinates of the polygon that have the smallest distance to each vertex.

4. The active alignment method for a zoom camera module as described in claim 3, characterized in that, The zoom camera module includes at least three focal lengths.

5. The active alignment method for a zoom camera module as described in claim 1, characterized in that, The step of sequentially adjusting the optical center of the zoom camera module at the multiple focal lengths specifically includes: Drive the lens to translate or rotate relative to the sensor to align the lens and the sensor; Alternatively, the sensor can be driven to translate or rotate relative to the lens to align the lens and the sensor.

6. The active alignment method for a zoom camera module as described in claim 5, characterized in that, The step of sequentially adjusting the optical center of the zoom camera module at the multiple focal lengths also includes: Acquire an image of the test target from the current relative position of the lens and the sensor; The alignment of the lens and the sensor is determined by whether the center of the test target is located at the center of the image.

7. The active alignment method for a zoom camera module as described in claim 1, characterized in that, The step of determining whether the lens and the sensor are aligned based on the set of calibration SFR values ​​specifically includes: Each SFR value in the set of calibration SFR values ​​is compared with a preset SFR value; If each SFR value in the set of calibration SFR values ​​is greater than or equal to the preset SFR value, then it is determined that the lens and the sensor are aligned. If any SFR value in a set of calibration SFR values ​​is less than the preset SFR value, then it is determined that the lens and the sensor are not aligned.

8. The active alignment method for the zoom camera module as described in claim 7, characterized in that, The active alignment method for the zoom camera module also includes: When it is determined that the lens and the sensor are not aligned, a new adjustment scheme is obtained by calculating the adjustment scheme of the zoom camera module based on the current set of calibration SFR values. Based on the new adjustment scheme, a new set of calibration SFR values ​​is obtained by re-acquiring the SFR values ​​of the zoom camera module at different focal lengths. Based on the new set of calibration SFR values, determine whether the lens and the sensor are aligned. When the lens and the sensor are aligned, the positional relationship between the lens and the sensor is fixed; or The zoom camera module is deemed unqualified when the new adjustment scheme has been implemented a preset number of times and the lens and sensor are still not aligned.

9. The active alignment method for a zoom camera module as described in claim 8, characterized in that, The specific steps for obtaining the SFR value of the zoom camera module at different focal lengths include: Multiple calibration images are obtained by acquiring images captured by the zoom camera module at different focal lengths; The SFR values ​​of each calibration image at the center and four corners are obtained to obtain the SFR values ​​at different focal lengths; Specifically, the process of calculating the adjustment scheme for the zoom camera module based on the initial set of SFR values, or calculating the adjustment scheme for the zoom camera module based on the current set of calibration SFR values, to obtain a new adjustment scheme includes: The SRF values ​​at the center of each calibration image are summed to obtain the center SFR value; The SRF values ​​of each calibration image at each corner are summed to obtain the SFR value of each corner; The horizontal translation amount and the vertical translation amount are determined based on the center SFR value and the SFR values ​​of each corner, respectively. The horizontal translation amount represents the adjustment of the lens or the sensor in the horizontal direction, and the vertical translation amount represents the adjustment of the lens or the sensor in the vertical direction.

10. An active alignment device, characterized in that, Active alignment devices include: Memory, used to store computer programs; and A processor for executing the computer program to implement the active alignment method of the zoom camera module as claimed in any one of claims 1-9.

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