An optical lens surface micro-defect detection device and method

Abstract

The application provides an optical lens surface micro-defect detection device and method, and belongs to the technical fields of optical element quality detection, precision machine vision detection and multi-axis precision motion control, and comprises a main body frame, a multi-axis precision motion platform, a lens clamping mechanism, an imaging unit, a uniform light illumination unit, an upper computer unit and a control unit; lens detection is finally completed through detection device initialization, lens feeding and clamping positioning, parameter setting and input, global automatic focusing and curved surface tracking, image processing and defect identification, region skipping, global image splicing, defect grading and result output, and automatic generation of a standardized detection report by the upper computer unit; global posture adjustment and curved surface tracking of the lens are realized through multi-axis linkage, blind areas in detection are eliminated, the imaging clarity of the whole surface of the lens is ensured to be consistent, manual intervention errors are reduced, and the overall detection efficiency and detection consistency are improved.

Description

Technical Field

[0001] This invention belongs to the fields of optical component quality inspection, precision machine vision inspection, and multi-axis precision motion control technology. In particular, it relates to a device and method for detecting micro-defects on the surface of optical lenses, which is based on an imaging method and can achieve rapid, full-range, and high-precision detection of micron-level defects on the surface of spherical and aspherical optical lenses. Background Technology

[0002] Optical lenses are widely used in cameras, microscopes, laser equipment, medical devices, and other fields. Their surface quality directly determines the imaging effect, stability, and lifespan of the optical system. Even tiny defects on the lens surface, such as scratches, pitting, edge chipping, and coating peeling, even if only a few micrometers in size, can seriously affect optical performance. Therefore, high-precision detection of surface defects in lenses is an indispensable quality control step in the production process of optical components.

[0003] Currently, the main technical shortcomings in optical lens surface defect detection are as follows: (1) Traditional detection methods rely on manual visual observation, supplemented by a simple magnifying glass. Not only is the detection efficiency low, but the detection time for a single piece usually exceeds 5 minutes. Furthermore, it is highly subjective and greatly affected by the experience and fatigue level of the inspectors. It cannot reliably identify minute defects, and the rate of missed detection and false detection remains high, making it difficult to meet the needs of high-precision quality inspection. (2) Existing testing equipment is mostly designed for flat lenses or simple small-angle lenses. It cannot be fully automatically tested for lenses that need to be tested on both sides and whose upper and lower sides are different surfaces. In addition, the traditional fixed-viewpoint and fixed-focus imaging method cannot achieve clear focus across the entire area, which easily leads to blind spots in the detection, resulting in defects at curved edges and curvature abrupt changes that cannot be detected. (3) Ordinary imaging inspection systems have a single illumination mode and insufficient focusing accuracy. Reflection and shadow interference are prone to occur during the imaging process, resulting in low contrast between defects and lens surface. They cannot stably achieve micron-level defect resolution accuracy and cannot meet the quality inspection requirements of high-end optical lenses.

[0004] Therefore, developing a fully automated device that can adapt to complex surface shapes and stably achieve high-precision detection of micron-level defects has become an urgent need in the field of optical inspection. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a device and method for detecting micro-defects on the surface of optical lenses. This device can detect optical lenses with arbitrary combinations of concave, convex, and planar shapes and curvatures. Through multi-axis linkage, it achieves full-range lens attitude adjustment and surface tracking, eliminating blind spots, optimizing the imaging and illumination systems, and enabling stable detection of micron-level defects. This ensures clear defect imaging and high contrast, reducing the false negative and false positive rates. Furthermore, it achieves coordinated control of multi-axis linkage and automatic focusing, guaranteeing consistent image clarity across the entire lens surface, improving detection accuracy and stability. The entire detection process is automated, reducing human intervention errors and improving overall detection efficiency and consistency.

[0006] In a first aspect, an optical lens surface micro-defect detection device includes: The main frame, multi-axis precision motion platform, lens clamping mechanism, imaging unit, uniform illumination unit, host computer unit, and control unit; The main frame is used to support the multi-axis precision motion platform. The multi-axis precision motion platform is used to achieve full-range attitude adjustment and surface tracking of the lens under test; in conjunction with the autofocus system and ultra-depth-of-field imaging algorithm, it enables clear imaging of lenses with different curvatures. The lens clamping mechanism is used to quickly clamp, center, and fix the lens to be tested.

[0007] The imaging unit includes a camera and an objective lens for acquiring image data of the surface of the lens to be inspected. The camera is electrically connected to the host computer unit via a network port and transmits the acquired image data to the host computer unit in real time. The imaging unit adopts a super depth-of-field imaging algorithm, which achieves high-resolution and rapid detection of complex curved surfaces by combining trajectory prediction with rapid micro-motion and depth-of-field fusion. The uniform illumination unit includes: a main illumination unit, an auxiliary illumination unit, a supplementary illumination unit, and an illumination control module; it automatically adjusts the brightness and angle of the illumination according to the material and defect type of the lens to be inspected, ensuring that different types of micron-level defects can be clearly imaged; The host computer unit is used to process the acquired image data, identify and analyze defects, store the detection data, and generate a detection report; and to generate a detection control program to the control unit based on the parameters of the lens to be tested; and to generate illumination parameters to the uniform illumination unit. The control unit includes a motion control card and a servo driver, used to realize the linkage control of the multi-axis precision motion platform.

[0008] As an example, the multi-axis precision motion platform includes: an XY translation mechanism, a θ-axis rotation mechanism (i.e., a rotation mechanism around the X-axis), a γ-axis rotation mechanism (i.e., a rotation mechanism around the Y-axis), and a Z-axis lifting mechanism.

[0009] Furthermore, the XY translation mechanism is used to move the lens to be tested on a horizontal plane to achieve planar scanning of the lens surface; The θ-axis rotation mechanism is used to adjust the attitude angle of the lens, adapt to the curvature changes in different areas of the aspherical lens, ensure that all points on the curved surface of the lens are perpendicular to the objective lens, and eliminate imaging parallax and blur problems.

[0010] The γ-axis rotation mechanism is used in conjunction with the θ-axis rotation mechanism to adjust the lens angle according to the surface shape and curvature of the lens to be tested, so as to ensure that the normal of the current detection area is parallel to the optical axis of the imaging unit. The θ-axis rotation mechanism and the γ-axis rotation mechanism are concentrically mounted on the XY translation mechanism; The Z-axis lifting mechanism is used to adjust the height of the imaging unit; (the Z-axis lifting mechanism and the XY translation mechanism can also be connected together. In this case, the Z-axis lifting mechanism is used to adjust the height of the lens to be tested. However, this overall structure would increase the Z-axis load, and this method is not adopted in this invention.) As an example, the lens clamping mechanism adopts a three-point centering clamping structure, including three adjustable clamping jaws.

[0011] As an example, the clamping claw is made of soft rubber, which can avoid scratching the surface of the lens. After clamping, the lens to be tested does not have obvious deformation, ensuring the stability of the lens's posture during the testing process.

[0012] As an example, the imaging unit employs an active stray light suppression structure to ensure the imaging signal-to-noise ratio of micron-level defects; specifically, it is a cavity structure comprising a black anodized aluminum alloy cavity with matte threads machined on the inner wall of the cavity; and the inner wall of the cavity is sprayed with nano-level matte paint to further absorb residual reflected light.

[0013] As an example, the imaging unit is installed on one side of the Z-axis lifting mechanism to provide image data for defect identification.

[0014] As an example, the camera is a high-resolution industrial camera; the objective lens is a high-precision imaging lens.

[0015] As an example, the uniform illumination unit is coaxially arranged with the objective lens, and adopts a composite illumination method combining coaxial light with ring light and side light, wherein: ① The main illumination unit is a coaxial light source with adjustable brightness. The light beam is coaxial with the objective lens and is used to acquire reference images. ② The auxiliary lighting unit is a ring light arranged around the objective lens, and the light shines evenly in a ring, which enhances the gradient lighting in the edge area of ​​the curved surface and is used to compensate for the illuminance attenuation of the main lighting unit at the point of curvature change. ③ The supplementary illumination unit is a side light, and the light source and angle are adjustable. It is used to provide uniform and non-reflective illumination for the surface of the lens to be inspected, improve the contrast between the defect and the lens surface, and ensure clear imaging of tiny defects. The main lighting unit, auxiliary lighting unit, and supplementary lighting unit are controlled by the lighting control module. The brightness and angle of each lighting unit are automatically adjusted according to the lens material and defect type to ensure that different types of micron-level defects can be clearly imaged.

[0016] As an example, the uniform illumination unit also adopts a cavity structure, which has anti-reflective and dustproof properties, reduces the interference of external light and dust on imaging quality, and ensures detection accuracy.

[0017] As an example, the host computer unit includes a computer, an image processor, and a display.

[0018] As an example, the control unit is electrically connected to the multi-axis precision motion platform, the servo driver is connected to the motion control card, and the motion control card is electrically connected to the host computer unit; according to the preset scanning path, precise linkage is achieved through detection and control program path, which has a high response speed and smooth movement without shaking.

[0019] Secondly, a method for detecting micro-defects on the surface of an optical lens includes: Step 1: Initialize the detection device; Turn on the power, and the testing device will automatically perform a system self-test; As an example, the system self-test includes the status detection of the multi-axis precision motion platform, the imaging unit, and the control unit.

[0020] Step 2: Lens loading and clamping positioning; The lens clamping mechanism enables precise centering and fixation of the lens to be tested. As an example, the lens to be tested includes a spherical lens or an aspherical lens. The lens to be tested is placed on the lens clamping mechanism, and the position of the clamping jaws is automatically adjusted to achieve precise centering and fixing of the lens to be tested.

[0021] Step 3: Parameter setting and input; The parameters of the lens to be tested are entered into the host computer unit. Based on the entered lens parameters, the host computer unit automatically generates the detection control program and illumination parameters. As an example, the parameters of the lens to be tested include: lens type, diameter, curvature, thickness, and testing parameters.

[0022] As an example, the detection control program is executed by the control unit to control the multi-axis precision motion platform to achieve the optimal multi-axis scanning path.

[0023] Step 4: Global autofocus and surface tracking; At the start of the inspection, the control unit controls the multi-axis precision motion platform to move the lens to be inspected, and at the same time the imaging unit and the uniform illumination unit are activated; the image sharpness evaluation function and the depth imaging algorithm are combined to perform image data acquisition and defect identification. As an example, to ensure accurate identification of every defect on the curved lens, at each imaging position, an image sharpness evaluation function is first used. Based on the sharpness feedback of the image's central region, the Z-axis height and θ-axis attitude angle are automatically adjusted for precise focusing, completing the first image acquisition at the current imaging position. Then, based on the curvature trajectory, the Z-axis direction is adjusted, and two more images are acquired for the depth-of-field imaging algorithm, achieving clear imaging across the entire surface and aperture of the lens under inspection. The specific process is as follows: (1) Trajectory pre-calculation: The host computer unit divides the convex surface into M×N (that is, according to the mirror size and surface shape, and according to the imaging field of view, the mirror is divided into M*N blocks in the horizontal and vertical directions) imaging grid regions based on the lens surface shape equation, and calculates the ideal focal plane height Z_i and rotation axis angle of the center point of each region. , (0≤i<M*N); (2) Multi-axis simultaneous scanning: The XY translation mechanism moves the lens to be tested to the center of the i-th region, X. i Y i ; Adjust the Z-axis lifting mechanism to the pre-calculated height Z. i ; The θ-axis rotation mechanism and the γ-axis rotation mechanism adjust the orientation of the lens to be tested, so that the normal vector of the detection area of ​​the lens to be tested is parallel to the optical axis of the imaging unit. (3) Precise focusing and imaging: Start image sharpness evaluation, acquire 3 images (Zi-Δz, Zi, Z+Δz), and select the optimal focal plane through sharpness evaluation; Δz is dynamically adjusted based on the lens depth of field, and is selected as 1 / 3 of the depth of field to ensure that the best focus position is not missed; super depth of field fusion is then performed.

[0024] Step 5: Image processing and defect identification; The host computer unit preprocesses the acquired local images, including noise suppression, grayscale correction, and removal of vignetting.

[0025] Step 6: Area jump; After completing the current area, the XY translation mechanism moves to the next area and repeats steps 2-3. Step 7: Global image stitching; The host computer unit uses a feature point-based image stitching algorithm to fuse M×N region images into a complete lens surface image, and the defect location is mapped to the actual coordinate system of the lens through coordinate transformation; Step 8: Defect classification and result output; The host computer unit automatically grades the quality of the lens based on the preset defect level judgment criteria, combined with the type, size and quantity of defects; As an example, the quality grading includes: qualified, unqualified, and pending.

[0026] Step 9: The host computer unit automatically generates a standardized test report; As an example, the standardized test report includes information such as lens parameters, test parameters, defect images, defect locations, defect sizes, and quality grades, which facilitates subsequent traceability.

[0027] Step 10: Lens cutting; After the test is completed, the built-in software of the host computer unit will give a test completion prompt; the operator will take out the tested lens to complete a single test. As an example, if continuous lens testing is required, simply repeat steps 2-9.

[0028] Thirdly, this application discloses an electronic device comprising: a processor; and a memory for storing processor-executable instructions; wherein the processor is configured to perform a method for detecting micro-defects on the surface of an optical lens as described above.

[0029] Thirdly, this application discloses a non-transitory computer-readable storage medium, wherein when the instructions in the storage medium are executed by a processor of an electronic device, the electronic device is able to perform a method for detecting micro-defects on the surface of an optical lens as described above.

[0030] Fourthly, this application discloses a computer program product that, when the instructions in the computer program product are executed by the processor of an electronic device, enables the electronic device to perform a method for detecting micro-defects on the surface of an optical lens as described above.

[0031] The beneficial effects of this invention are: Compared with the prior art, the present invention has the following significant advantages: (1) It adopts an integrated structure, is compact and flexible in deployment, adapts to the high-precision lens quality inspection requirements, is easy to operate, and can be used by professionals without the need for professional technicians; (2) It is compatible with both spherical and aspherical optical lenses. The five-axis linkage motion platform realizes the full-range attitude adjustment and surface tracking of the lens, eliminating the detection blind zone caused by the curvature change of the aspherical lens surface, and realizing the detection of the entire surface and the entire aperture of the lens without dead angles. (3) The high-resolution imaging and uniform illumination system has been optimized, resulting in clear imaging and high contrast. It can stably detect minute defects and meet the quality inspection requirements of high-end optical lenses. (4) It realizes the coordinated control of multi-axis linkage and autofocus, and adjusts the focus position and lens posture in real time through image sharpness feedback to ensure consistent image sharpness across the entire lens surface and stable detection accuracy; (5) The entire inspection process is automated, from lens clamping, parameter setting, scanning imaging, defect identification to report output, without the need for continuous manual intervention, which improves inspection efficiency and consistency and reduces labor costs. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the overall structure of an optical lens surface micro-defect detection device according to the present invention.

[0033] Figure 2 This is a schematic diagram of the uniform illumination unit structure of an optical lens surface micro-defect detection device according to the present invention.

[0034] Figure 3 This is a schematic diagram of the overall process of a method for detecting micro-defects on the surface of an optical lens according to the present invention. Detailed Implementation

[0035] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. Figures 1 to 3 As shown.

[0036] In a first aspect, an optical lens surface micro-defect detection device includes: The main frame 101, multi-axis precision motion platform, lens clamping mechanism 102, imaging unit 103, uniform illumination unit 104, host computer unit 105, and control unit; The main frame 101 is used to support the multi-axis precision motion platform. The multi-axis precision motion platform is used to achieve full-range attitude adjustment and surface tracking of the lens under test; in conjunction with the autofocus system and ultra-depth-of-field imaging algorithm, it enables clear imaging of lenses with different curvatures. The lens clamping mechanism 102 is used to quickly clamp, center, and fix the lens to be tested.

[0037] The imaging unit 103 includes a camera 201 and an objective lens 202, used to acquire image data of the surface of the lens to be inspected. The camera is electrically connected to the host computer unit through a network port and transmits the acquired image data to the host computer unit in real time. The imaging unit adopts a super depth-of-field imaging algorithm, which achieves high-resolution and rapid detection of complex curved surfaces by combining trajectory prediction with rapid micro-motion and depth-of-field fusion. The uniform illumination unit 104 includes: a main illumination unit, an auxiliary illumination unit, a supplementary illumination unit, and an illumination control module; it automatically adjusts the brightness and angle of the illumination according to the material and defect type of the lens to be inspected, ensuring that different types of micron-level defects can be clearly imaged; The host computer unit 105 is used to process the acquired image data, identify and analyze defects, store the detection data, and generate a detection report; and generate a detection control program to the control unit according to the parameters of the lens to be detected; and at the same time generate illumination parameters to the uniform illumination unit. The control unit includes a motion control card 106 and a servo driver 107, used to realize the linkage control of the multi-axis precision motion platform.

[0038] As an example, the multi-axis precision motion platform includes: an XY translation mechanism, an θ-axis rotation mechanism 108 (i.e., a rotation mechanism around the X-axis), a γ-axis rotation mechanism 109 (i.e., a rotation mechanism around the Y-axis), and a Z-axis lifting mechanism 112.

[0039] As an example, the XY translation mechanism includes: an X-axis translation mechanism 110 and a Y-axis translation mechanism 111.

[0040] Furthermore, the XY translation mechanism is used to move the lens to be tested on the horizontal plane to achieve planar scanning of the surface of the lens to be tested; The θ-axis rotation mechanism is used to adjust the attitude angle of the lens under test, adapt to the curvature changes in different areas of the aspherical lens, ensure that all points on the curved surface of the lens under test are perpendicular to the objective lens, and eliminate imaging parallax and blur problems.

[0041] The γ-axis rotation mechanism is used in conjunction with the θ-axis rotation mechanism to adjust the lens angle according to the surface shape and curvature of the lens to be tested, so as to ensure that the normal of the current detection area is parallel to the optical axis of the imaging unit. The θ-axis rotation mechanism and the γ-axis rotation mechanism are concentrically mounted on the XY translation mechanism; The Z-axis lifting mechanism 112 is used to adjust the height of the imaging unit 103; (The Z-axis lifting mechanism and the XY translation mechanism can also be connected together. In this case, the Z-axis lifting mechanism is used to adjust the height of the lens to be tested. However, this overall structure would increase the Z-axis load, which is not adopted in this invention.) As an example, the lens clamping mechanism 102 adopts a three-point centering clamping structure, including three adjustable clamping jaws.

[0042] As an example, the clamping claw is made of soft rubber, which can avoid scratching the surface of the lens. After clamping, the lens to be tested does not have obvious deformation, ensuring the stability of the lens's posture during the testing process.

[0043] As an example, the imaging unit 103 adopts an active stray light suppression structure to ensure the imaging signal-to-noise ratio of micron-level defects; specifically, it is a cavity structure, including a black anodized aluminum alloy cavity with matte threads processed on the inner wall of the cavity; and the inner wall of the cavity is sprayed with nano-level matte paint to further absorb residual reflected light.

[0044] As an example, the imaging unit 103 is installed on one side of the Z-axis lifting mechanism 112 to provide image data for defect identification.

[0045] As an example, the camera 201 is a high-resolution industrial camera; the objective lens 202 is a high-precision imaging lens.

[0046] As an example, the uniform illumination unit 104 is coaxially arranged with the objective lens, and adopts a composite illumination method combining coaxial light with ring light and side light, wherein: ①The main illumination unit is a coaxial light 203 with adjustable brightness. The light beam is coaxial with the objective lens and is used to acquire reference images. ② The auxiliary lighting unit is a ring light 204, which is arranged around the objective lens. The light shines in a ring and is uniformly illuminated, which enhances the gradient illumination of the curved edge area and is used to compensate for the illuminance attenuation of the main lighting unit at the point of curvature change. ③ The supplementary lighting unit is a side light 205, the light source and angle of which are adjustable. It is used to provide uniform, non-reflective illumination for the lens surface, improve the contrast between defects and the lens surface, and ensure clear imaging of minute defects. The supplementary lighting unit can have various forms of side light, such as circular, directional, and ring-shaped.

[0047] The main lighting unit, auxiliary lighting unit, and supplementary lighting unit are controlled by the lighting control module. The brightness and angle of each lighting unit are automatically adjusted according to the lens material and defect type to ensure that different types of micron-level defects can be clearly imaged.

[0048] As an example, the uniform illumination unit 104 also adopts a cavity structure, which has anti-reflective and dustproof properties, reduces the interference of external light and dust on imaging quality, and ensures detection accuracy.

[0049] As an example, the host computer unit 105 includes a computer, an image processor, and a display.

[0050] As an example, the control unit is electrically connected to the multi-axis precision motion platform, the servo driver 107 is connected to the motion control card 106, and the motion control card 106 is electrically connected to the host computer unit 105; according to the preset scanning path, precise linkage is achieved through detection control program path, which has a high response speed and smooth movement without shaking.

[0051] Secondly, a method for detecting micro-defects on the surface of an optical lens includes: Step 1: Initialize the detection device; Turn on the power, and the testing device will automatically perform a system self-test; As an example, the system self-test includes the status detection of the multi-axis precision motion platform, the imaging unit 103, and the control unit.

[0052] Step 2: Lens loading and clamping positioning; The lens clamping mechanism 102 enables precise centering and fixation of the lens to be tested. As an example, the lens to be tested includes a spherical lens or an aspherical lens. The lens to be tested is placed on the lens clamping mechanism 102, and the position of the clamping claws is automatically adjusted to achieve precise centering and fixing of the lens to be tested.

[0053] Step 3: Parameter setting and input; The parameters of the lens to be tested are entered into the host computer unit 105. Based on the entered parameters of the lens to be tested, the host computer unit 105 automatically generates the detection control program and illumination parameters. As an example, the parameters of the lens to be tested include: lens type, diameter, curvature, thickness, and testing parameters.

[0054] As an example, the detection control program is executed by the control unit to control the multi-axis precision motion platform to achieve the optimal multi-axis scanning path.

[0055] Step 4: Global autofocus and surface tracking; When the test begins, the control unit controls the multi-axis precision motion platform to move the lens to be tested, and at the same time the imaging unit 103 and the uniform illumination unit 104 are activated; the image sharpness evaluation function and the depth imaging algorithm are combined to perform image data acquisition and defect identification. As an example, to ensure that every defect on the curved lens can be accurately identified, at each imaging position, an image sharpness evaluation function is first used. Based on the sharpness feedback of the image center area, the Z-axis height and θ-axis attitude angle are automatically adjusted for precise focusing, completing the first image acquisition at the current imaging position. Then, based on the curvature trajectory, the Z-axis direction is adjusted, and two more images are acquired for the depth imaging algorithm, achieving clear imaging across the entire surface and aperture of the lens under test. The specific process is as follows: (1) Trajectory pre-calculation: The host computer unit divides the convex surface into M×N (that is, according to the mirror size and surface shape, and according to the imaging field of view, the mirror is divided into M*N blocks in the horizontal and vertical directions) imaging grid regions based on the lens surface shape equation, and calculates the ideal focal plane height Z_i and rotation axis angle of the center point of each region. , (0≤i<M*N); (2) Multi-axis simultaneous scanning: The XY translation mechanism moves the lens to be tested to the center of the i-th region, X. i Y i ; Adjust the Z-axis lifting mechanism to the pre-calculated height Z. i ; The θ-axis rotation mechanism and the γ-axis rotation mechanism adjust the orientation of the lens to be tested, so that the normal vector of the detection area of ​​the lens to be tested is parallel to the optical axis of the imaging unit. (3) Precise focusing and imaging: Start image sharpness evaluation, acquire 3 images (Zi-Δz, Zi, Z+Δz), and select the optimal focal plane through sharpness evaluation; Δz is dynamically adjusted based on the lens depth of field, and is selected as 1 / 3 of the depth of field to ensure that the best focus position is not missed; super depth of field fusion is then performed.

[0056] Step 5: Image processing and defect identification; The host computer unit preprocesses the acquired local images, including noise suppression, grayscale correction, and removal of vignetting.

[0057] Step 6: Area jump; After completing the current area, the XY translation mechanism moves to the next area and repeats steps 2-3. Step 7: Global image stitching; The host computer unit 105 uses a feature point-based image stitching algorithm to fuse M×N region images into a complete lens surface image, and the defect location is mapped to the actual coordinate system of the lens through coordinate transformation; Step 8: Defect classification and result output; The host computer unit 105 automatically grades the quality of the lens according to the preset defect level judgment standard, combined with the type, size and quantity of defects; As an example, the quality grading includes: qualified, unqualified, and pending.

[0058] Step 9: The host computer unit 105 automatically generates a standardized test report; As an example, the standardized test report includes information such as lens parameters, test parameters, defect images, defect locations, defect sizes, and quality grades, which facilitates subsequent traceability.

[0059] Step 10: Lens cutting; After the test is completed, the built-in software of the host computer unit 105 will give a test completion prompt; the operator will take out the tested lens to complete a single test. As an example, if continuous lens testing is required, simply repeat steps 2-9.

[0060] Thirdly, this application discloses an electronic device comprising: a processor; and a memory for storing processor-executable instructions; wherein the processor is configured to perform a method for detecting micro-defects on the surface of an optical lens as described above.

[0061] Thirdly, this application discloses a non-transitory computer-readable storage medium, wherein when the instructions in the storage medium are executed by a processor of an electronic device, the electronic device is able to perform a method for detecting micro-defects on the surface of an optical lens as described above.

[0062] Fourthly, this application discloses a computer program product that, when the instructions in the computer program product are executed by the processor of an electronic device, enables the electronic device to perform a method for detecting micro-defects on the surface of an optical lens as described above.

[0063] To better illustrate the design principle of this invention, the calculation of the coordinates and attitude angles of each region of the lens to be tested is described in detail below: (1) Let the size corresponding to the imaging field of view be . (mm), lens diameter is D; The projection of the lens onto the XY plane is divided into M×N rectangular grids, and we take:

[0064] The coordinates of each region are:

[0065] Among them, m=1…M, n=1…N, Δx=Vx, Δy=Vy.

[0066] Surface equation: The vertex of the sphere is at the origin, and the optical axis is the Z-axis. convex surface concave surface Normal vector calculation: At point (X) i , Yj, Z ii At point (), the normal vector of the sphere is:

[0067] (4) Calculate θᵢⱼ; To make the normal vector at a point on the lens surface parallel to the imaging optical axis (Z-axis direction), the lens needs to be rotated. Assuming the rotation sequence is first θ around the X-axis, then γ around the Y-axis, the required angle is:

[0068] This invention provides a fully automated lens surface defect measurement device and method capable of automatic lens flipping, adapting to the high-precision lens quality inspection requirements. It can inspect optical lenses with arbitrary combinations of concave, convex, and planar shapes and curvatures. Through multi-axis linkage, it achieves full-range lens attitude adjustment and surface tracking, eliminating blind spots and enabling comprehensive, dead-angle-free inspection. Optimized imaging and illumination systems ensure stable detection of micron-level defects, guaranteeing clear and high-contrast defect imaging, reducing false negative and false positive rates. Multi-axis linkage and automatic focusing are coordinated to ensure consistent image clarity across the entire lens surface, improving detection accuracy and stability. The entire inspection process is automated, reducing manual intervention, improving inspection efficiency and consistency, and lowering labor costs.

[0069] It should be noted that, for the sake of simplicity, the method embodiments are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, because according to this application, some steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also understand that the embodiments described in the specification are all optional embodiments, and the actions involved are not necessarily required by this application.

[0070] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0071] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal (which may be a mobile phone, computer, server, air conditioner, or network device, etc.) to execute the methods described in the various embodiments of this application.

[0072] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

[0073] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed in this application can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0074] Those skilled in the art will 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.

[0075] In the embodiments provided in this application, it should be understood that the disclosed apparatus 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 through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0076] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they 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.

[0077] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0078] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they 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 a portion 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 a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, ROM, RAM, magnetic disks, or optical disks.

[0079] The above description is only a preferred embodiment of the present invention. It should be understood that the above description of the embodiments is only for the purpose of helping to understand the method and core idea of ​​the present invention, and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, etc. made within the idea and principle of the present invention should be included within the scope of protection of the present invention.

Claims

1. A device for detecting micro-defects on the surface of an optical lens, characterized in that, include: Main frame: Used to support the multi-axis precision motion platform; Multi-axis precision motion platform: used to achieve full-range attitude adjustment and surface tracking of the lens under test; combined with autofocus system and ultra-depth-of-field imaging algorithm, to achieve clear imaging of lenses with different curvatures; Lens clamping mechanism: used to quickly clamp, center, and fix the lens to be tested; Imaging unit: used to acquire image data of the surface of the lens to be inspected. The camera is electrically connected to the host computer unit via a network port and transmits the acquired image data to the host computer unit in real time. The imaging unit adopts a super depth-of-field imaging algorithm, which achieves high-resolution and rapid detection of complex curved surfaces by combining trajectory prediction with rapid micro-motion and depth-of-field fusion. The uniform illumination unit includes: automatically adjusting the brightness and angle of the illumination according to the material and defect type of the lens to be inspected, so as to ensure that different types of micron-level tiny defects can be clearly imaged; The host computer unit is used to process the acquired image data, identify and analyze defects, store the detection data, and generate a detection report; and to generate a detection control program to the control unit based on the parameters of the lens to be tested; and to generate illumination parameters to the uniform illumination unit. The control unit is used to realize the linkage control of the multi-axis precision motion platform.

2. The optical lens surface micro-defect detection device according to claim 1, characterized in that, The multi-axis precision motion platform includes: an XY translation mechanism, a θ-axis rotation mechanism, a γ-axis rotation mechanism, and a Z-axis lifting mechanism; The XY translation mechanism is used to move the lens to be tested on the horizontal plane. The θ-axis rotation mechanism is used to adjust the attitude angle of the lens. The γ-axis rotation mechanism is used in conjunction with the θ-axis rotation mechanism to adjust the lens angle according to the surface shape and curvature of the lens to be tested. The θ-axis rotation mechanism and the γ-axis rotation mechanism are concentrically mounted on the XY translation mechanism; The Z-axis lifting mechanism is used to adjust the height of the imaging unit.

3. The optical lens surface micro-defect detection device according to claim 1, characterized in that, The lens clamping mechanism adopts a three-point centering clamping structure, including three adjustable clamping jaws.

4. The optical lens surface micro-defect detection device according to claim 1, characterized in that, The imaging unit includes a camera and an objective lens, employing an active stray light suppression structure; the imaging unit is mounted on one side of the Z-axis lifting mechanism to provide image data for defect identification; the camera is a high-resolution industrial camera; the objective lens is a high-precision imaging lens.

5. The optical lens surface micro-defect detection device according to claim 4, characterized in that, The stray light suppression structure includes: a black anodized aluminum alloy cavity with matte threads machined on the inner wall of the cavity; and a nano-level matte paint sprayed on the inner wall of the cavity.

6. The optical lens surface micro-defect detection device according to claim 1, characterized in that, The uniform illumination unit is coaxially arranged with the objective lens and includes: a main illumination unit, an auxiliary illumination unit, a supplementary illumination unit, and an illumination control module; it adopts a composite illumination method combining coaxial light with ring light and side light, wherein: ① The main illumination unit is a coaxial light source with adjustable brightness. The light beam is coaxial with the objective lens and is used to acquire reference images. ② The auxiliary lighting unit is a ring light arranged around the objective lens, and the light shines evenly in a ring, which enhances the gradient lighting in the edge area of ​​the curved surface and is used to compensate for the illuminance attenuation of the main lighting unit at the point of curvature change. ③ The supplementary illumination unit is a side light, and the light source and angle are adjustable. It is used to provide uniform and non-reflective illumination for the surface of the lens to be inspected, improve the contrast between the defect and the lens surface, and ensure clear imaging of tiny defects. The main lighting unit, auxiliary lighting unit, and supplementary lighting unit are controlled by the lighting control module.

7. The optical lens surface micro-defect detection device according to claim 1, characterized in that, The host computer unit includes a computer, an image processor, and a display.

8. The optical lens surface micro-defect detection device according to claim 1, characterized in that, The control unit is electrically connected to the multi-axis precision motion platform and includes: a motion control card and a servo driver. The servo driver is connected to the motion control card, and the motion control card is electrically connected to the host computer unit. Precise linkage is achieved by detecting and controlling the path according to a preset scanning path.

9. A method for detecting micro-defects on the surface of an optical lens, characterized in that, include: Step 1: Initialize the detection device; Turn on the power, and the testing device will automatically perform a system self-test; Step 2: Lens loading and clamping positioning; The lens clamping mechanism achieves precise centering and fixation of the lens to be tested; Step 3: Parameter setting and input; Input the parameters of the lens to be tested into the host computer unit. Based on the input lens parameters, the host computer unit automatically generates the detection control program and illumination parameters; The detection control program is executed by the control unit to control the multi-axis precision motion platform to achieve the optimal multi-axis scanning path; Step 4: Global autofocus and surface tracking; At the start of the inspection, the control unit controls the multi-axis precision motion platform to move the lens to be inspected, and at the same time the imaging unit and the uniform illumination unit are activated; Image data acquisition and defect identification are performed by combining the image sharpness evaluation function and the depth imaging algorithm. Step 5: Image processing and defect identification; The host computer unit preprocesses the acquired local images, including noise suppression, grayscale correction, and removal of vignetting; Step 6: Area jump; After completing the current area, the XY translation mechanism moves to the next area, and steps 2-3 are repeated; Step 7: Full-domain image stitching; The host computer unit uses a feature-point-based image stitching algorithm to fuse M×N region images into a complete lens surface image, and the defect location is mapped to the actual coordinate system of the lens through coordinate transformation; Step 8: Defect Classification and Result Output; The host computer unit automatically classifies the lens quality according to the preset defect level judgment criteria, combined with the type, size and quantity of defects. Step 9: The host computer unit automatically generates a standardized test report; Step 10: Lens unloading; after the inspection is completed, the built-in software of the host computer unit will give a prompt indicating that the inspection is complete; the operator takes out the inspected lens to complete a single inspection.

10. The method for detecting micro-defects on the surface of an optical lens according to claim 9, characterized in that, To ensure accurate identification of every defect on the curved lens, at each imaging position, an image sharpness evaluation function is first used. Based on the sharpness feedback of the image center area, the Z-axis height and θ-axis attitude angle are automatically adjusted for precise focusing, completing the first image acquisition at the current imaging position. Then, based on the curvature trajectory, the Z-axis direction is adjusted, and two more images are acquired for the depth imaging algorithm, achieving clear imaging across the entire surface and aperture of the lens under test. The specific process includes: ① Trajectory pre-calculation: Based on the lens surface shape equation, the host computer unit divides the convex surface into M×N imaging grid regions, and calculates the ideal focal plane height Z_i and rotation axis angle of the center point of each region. 、 ;0≤i<M*N; ② Multi-axis simultaneous scanning: The XY translation mechanism moves the lens to be tested to the center of the i-th region, X. i Y i ; Adjust the Z-axis lifting mechanism to the pre-calculated height Z. i ; The θ-axis rotation mechanism and the γ-axis rotation mechanism adjust the orientation of the lens to be tested, so that the normal vector of the detection area of ​​the lens to be tested is parallel to the optical axis of the imaging unit. ③ Precise focusing and imaging: Start image sharpness evaluation, acquire 3 images Zi-Δz, Zi, Z+Δz, and select the optimal focal plane through sharpness evaluation; Δz is dynamically adjusted based on the lens depth of field, and is selected as 1 / 3 of the depth of field to ensure that the best focus position is not missed; super depth of field fusion is then performed.

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