Active alignment device and method

Abstract

The invention discloses an active alignment device and method, which are applied to active alignment of a target lens and a target chip, and the device comprises a reverse projection shooting module which is configured to shoot a pixel image of the surface of the target chip through reverse projection of the target lens; and the processing control module is configured to control the target lens to be actively aligned with the target chip according to the feature information of the target chip in the pixel image and the definition information of the pixel image. According to the invention, an inverse projection visual shooting technology is adopted, and active alignment can be realized under the condition that a chip does not need to be electrified and a test target is not needed.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of automated manufacturing technology, and in particular to an active alignment device and method. Background Art

[0002] With the development of global IoT and autonomous driving technologies, the demand for cameras and lidars has increased significantly in autonomous vehicles and smart manufacturing factories, and higher precision requirements have been put forward for the clarity and consistency of cameras and lidars. For example, autonomous vehicles require forward-looking cameras to be used for distance measurement and collision avoidance, which requires cameras and lidars to have high assembly performance.

[0003] Active alignment (AA) technology is an assembly technology that automatically aligns the optical lens and the image sensor chip through fine automated assembly technology on the production line, so as to make the center of the optical lens and the center of the image sensor chip on the same axis perpendicular to the focal plane as much as possible, and make the image sensor chip on the focal plane of the optical lens and parallel to the optical lens, so as to obtain the best image quality. The application of AA technology can greatly improve the clarity of the camera, the accuracy of the optical axis alignment, and reduce the tilt of the focal plane, thereby improving the image acquisition quality and consistency of the camera and obtaining higher assembly performance.

[0004] However, the existing AA technology needs to be equipped with a high-precision test target when it is implemented, and the image sensor chip needs to be connected to a power supply to be powered on. Multiple tests and lens adjustments are required to complete the alignment of the focal plane. Therefore, the existing AA technology has the problems of low efficiency, poor versatility and high cost. Summary of the invention

[0005] An active alignment device and method provided in the embodiments of the present application can solve or partially solve the above-mentioned deficiencies in the prior art or other deficiencies in the prior art.

[0006] According to a first aspect of the present application, an active alignment device is provided, which is used for actively calibrating a target lens and a target chip. The device includes: a reverse projection shooting module, configured to shoot a pixel image of the surface of the target chip through reverse projection of the target lens; and a processing control module, configured to control the active alignment of the target lens and the target chip according to feature information of the target chip in the pixel image and clarity information of the pixel image.

[0007] In one embodiment of the present application, the reverse projection shooting module is configured to shoot a first pixel image of the target chip surface through reverse projection of the target lens; and to shoot a second pixel image of the target chip surface through reverse projection of the target lens during the movement of the target lens along the optical axis.

[0008] In one embodiment of the present application, the processing control module includes: an image processing unit, configured to detect the center deviation between the target lens and the target chip based on the feature information of the target chip surface in the first pixel image; detect the tilt angle between the target lens and the target chip based on the clarity information of the second pixel image; and a motion control unit, configured to control the movement of the target lens along the optical axis; and control the movement of the target lens to actively align with the target chip based on the center deviation and the tilt angle.

[0009] In one embodiment of the present application, the image processing unit is configured to divide each of the second pixel images into a number of image units according to a certain unit size; determine the contrast of the image unit according to the grayscale value of the pixel in each of the image units; and count the proportion of the number of image units of each second pixel image that is greater than a preset contrast threshold in all image units as the clarity information of the corresponding pixel image.

[0010] In one embodiment of the present application, the reverse projection shooting module includes: an industrial camera, configured to shoot a pixel image of the surface of the target chip illuminated by a coaxial light source through reverse projection of the target lens; and the coaxial light source, installed coaxially with the industrial camera in front of the industrial camera.

[0011] In one embodiment of the present application, the industrial camera is configured to shoot a pixel image of the surface of the target chip illuminated by the coaxial light source through the target lens and reverse projection in an infinite shooting mode.

[0012] In one embodiment of the present application, the effective focal length EFL1 of the industrial camera and the effective focal length EFL2 of the target lens satisfy: 3mm≤EFL1 / EFL2≤50mm.

[0013] In one embodiment of the present application, the industrial camera is configured to capture a pixel image of the surface of the target chip illuminated by the coaxial light source through the target lens and reverse projection in a limited distance shooting mode.

[0014] In one embodiment of the present application, the reverse projection shooting module includes: a plurality of the industrial cameras, which are configured to respectively shoot pixel images of a plurality of areas on the surface of the target chip illuminated by the coaxial light source through the target lens by reverse projection; and a plurality of the coaxial light sources, which are respectively installed coaxially with each of the industrial cameras in front of the plurality of the industrial cameras.

[0015] In one embodiment of the present application, the device includes: four industrial cameras, which are configured to respectively capture the first pixel images of the four corners of the surface of the target chip illuminated by the coaxial light source through the target lens through reverse projection; four coaxial light sources are respectively installed coaxially with each of the industrial cameras in front of the four industrial cameras; the image processing unit is configured to determine the actual position of the target lens and the center of the target chip based on the position information of the four corners of the surface of the target chip in the first pixel image, and determine the center deviation based on the actual position and the target position.

[0016] In one embodiment of the present application, the device includes: five industrial cameras, which are configured to respectively capture the second pixel images of the center and four corners of the target chip surface illuminated by the coaxial light source through the target lens reverse projection during the movement of the target lens along the optical axis; five coaxial light sources are respectively installed coaxially with each of the five industrial cameras in front of the five industrial cameras; the image processing unit is configured to determine the clearest position of the center and four corners of the target chip surface according to the clarity information of each pixel image in the second pixel image, and determine the inclination angle according to the clearest position.

[0017] In one embodiment of the present application, the device includes: four industrial cameras, which are configured to respectively capture the first pixel images of the four sides of the target chip surface illuminated by the coaxial light source through the target lens through reverse projection; four coaxial light sources are respectively installed coaxially with each of the industrial cameras in front of the four industrial cameras; the image processing unit is configured to determine the actual position of the target lens and the center of the target chip based on the position information of the four sides of the target chip surface in the first pixel image, and determine the center deviation based on the actual position and the target position.

[0018] In one embodiment of the present application, the device includes: five industrial cameras, which are configured to respectively capture second pixel images of the center and four sides of the target chip surface illuminated by the coaxial light source through the target lens reverse projection during the movement of the target lens along the optical axis; five coaxial light sources are respectively installed coaxially with each of the five industrial cameras in front of the five industrial cameras; the image processing unit is configured to determine the clearest position of the center and four sides of the target chip surface according to the clarity information of each pixel image in the second pixel image, and determine the inclination angle according to the clearest position.

[0019] According to a second aspect of the present application, an active alignment method is provided, which is applied to actively align a target lens with a target chip. The method comprises: photographing a pixel image of the surface of the target chip through reverse projection of the target lens; and controlling the active alignment of the target lens with the target chip based on feature information of the surface of the target chip in the pixel image and clarity information of the pixel image.

[0020] In one embodiment of the present application, photographing a pixel image of the target chip surface through reverse projection of the target lens includes: photographing a first pixel image of the target chip surface through reverse projection of the target lens; and controlling the target lens to move along the optical axis, and photographing a second pixel image of the target chip surface through reverse projection of the target lens during the movement of the target lens along the optical axis.

[0021] In one embodiment of the present application, the target lens is controlled to be actively aligned with the target chip according to the feature information of the target chip surface in the pixel image and the clarity information of the pixel image, including: detecting the center deviation between the target lens and the target chip according to the feature information of the target chip surface in the first pixel image; detecting the tilt angle between the target lens and the target chip according to the clarity information of the second pixel image; and controlling the movement of the target lens to actively align with the target chip according to the center deviation and the tilt angle.

[0022] In one embodiment of the present application, the tilt angle of the target lens and the target chip is detected according to the clarity information of the second pixel image, including: dividing each of the second pixel images into a plurality of image units according to a certain unit size; determining the contrast of the image unit according to the grayscale value of the pixel in each of the image units; and counting the proportion of the number of image units greater than a preset contrast threshold in all image units in each of the second pixel images as the clarity information of the corresponding second pixel image.

[0023] In one embodiment of the present application, photographing a pixel image of the target chip surface through reverse projection of the target lens includes: photographing a pixel image of the target chip surface illuminated by a coaxial light source through reverse projection of the target lens by an industrial camera, wherein the coaxial light source is installed coaxially with the industrial camera in front of the industrial camera.

[0024] In one embodiment of the present application, a pixel image of the target chip surface illuminated by a coaxial light source is photographed by an industrial camera through the target lens by reverse projection, comprising: photographing a pixel image of the target chip surface illuminated by the coaxial light source by the industrial camera through the target lens by reverse projection in an infinite distance shooting mode.

[0025] In one embodiment of the present application, the effective focal length EFL1 of the industrial camera and the effective focal length EFL2 of the target lens satisfy: 3mm≤EFL1 / EFL2≤50mm.

[0026] In one embodiment of the present application, a pixel image of the target chip surface illuminated by a coaxial light source is photographed by an industrial camera through the target lens by reverse projection, comprising: photographing a pixel image of the target chip surface illuminated by the coaxial light source by the industrial camera through the target lens by reverse projection in a finite distance shooting mode.

[0027] In one embodiment of the present application, a pixel image of the target chip surface illuminated by a coaxial light source is captured by an industrial camera through the target lens by reverse projection, comprising: using a plurality of industrial cameras to respectively capture pixel images of a plurality of areas of the target chip surface illuminated by the coaxial light source through the target lens by reverse projection, wherein a plurality of coaxial light sources are respectively installed coaxially with each of the industrial cameras in front of the plurality of industrial cameras.

[0028] In one embodiment of the present application, the method includes: using the four industrial cameras to respectively shoot the first pixel images of the four corners of the surface of the target chip illuminated by the coaxial light source through the target lens and reverse projection, wherein four coaxial light sources are respectively installed coaxially with each of the industrial cameras in front of the four industrial cameras; determining the actual position of the target lens and the center of the target chip according to the position information of the four corners of the surface of the target chip in the first pixel image, and determining the center deviation according to the actual position and the target position.

[0029] In one embodiment of the present application, the method includes: controlling the target lens to move along the optical axis, and in the process of the target lens moving along the optical axis, using the five industrial cameras to respectively shoot the second pixel image of the center and four corners of the target chip surface illuminated by the coaxial light source through the target lens and reverse projection, wherein five coaxial light sources are respectively installed coaxially with each of the five industrial cameras in front of the five industrial cameras; determining the clearest position of the center and four corners of the target chip surface according to the clarity information of each pixel image in the second pixel image, and determining the inclination angle according to the clearest position.

[0030] In one embodiment of the present application, the method includes: using the four industrial cameras to respectively shoot the first pixel images of the four sides of the target chip surface illuminated by the coaxial light source through the target lens and reverse projection, wherein four coaxial light sources are respectively installed coaxially with each of the industrial cameras in front of the four industrial cameras; determining the actual position of the target lens and the center of the target chip according to the position information of the four sides of the target chip surface in the first pixel image, and determining the center deviation according to the actual position and the target position.

[0031] In one embodiment of the present application, the method includes: controlling the target lens to move along the optical axis, and in the process of the target lens moving along the optical axis, using the five industrial cameras to respectively shoot the second pixel images of the center and four sides of the target chip surface illuminated by the coaxial light source through the target lens and reverse projection, wherein five coaxial light sources are respectively installed coaxially with each of the industrial cameras in front of the five industrial cameras; determining the clearest position of the center and four sides of the target chip surface according to the clarity information of each pixel image in the second pixel image, and determining the inclination angle according to the clearest position.

[0032] According to the active alignment device and method provided in the embodiments of the present application, the target lens and the target chip are actively aligned by adopting the reverse projection visual shooting technology. There is no need to power on and connect the target chip for communication, which can save the time for connecting the target chip to automatic plug-in devices such as power supply and data transmission, improve the efficiency of AA, and can be applicable to AA scenarios that do not support powered imaging; it can be compatible with different target chips, and there is no need to develop supporting control programs for drivers of different target chips. It has strong versatility and can save a lot of development time and cost; at the same time, by directly obtaining the pixel features on the surface of the target chip as a test target, there is no need for additional high-precision customized test targets, which can save costs and has strong versatility.

[0033] The content described in this section is not intended to identify the key or important features of the embodiments of the present disclosure, nor is it intended to limit the scope of the present disclosure. Other features of the present disclosure will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Other features, purposes and advantages of the present application will become more apparent by reading the detailed description of the non-limiting embodiments made with reference to the following drawings. The drawings are used to better understand the present solution and do not constitute a limitation of the present application. Among them:

[0035] Figure 1 is a schematic diagram of an implementation method of existing active alignment technology;

[0036] Figure 2 is a block diagram of an active alignment device according to an embodiment of the present application;

[0037] Figure 3 is a schematic diagram of reverse projection photography of an active alignment device according to an embodiment of the present application;

[0038] Figure 4 is a block diagram of an active alignment device according to another embodiment of the present application;

[0039] Figure 5 is a schematic diagram of reverse projection photography of an active alignment device according to an embodiment of the present application;

[0040] Figure 6 is a schematic diagram of an image clarity evaluation method according to another embodiment of the present application;

[0041] FIG. 7A to FIG. 7C is a schematic diagram of an example of reverse projection photography of an active alignment device according to the present application;

[0042] FIG. 8A to FIG. 8B is a schematic diagram of another example of reverse projection photography of the active alignment device according to the present application;

[0043] Fig.9A and Fig. 9B is a schematic diagram of another example of reverse projection photography of the active alignment device according to the present application;

[0044] Fig. 10A and Fig. 10B is a schematic diagram of another example of reverse projection photography of the active alignment device according to the present application;

[0045] Fig.11 is a schematic flow chart of an active alignment method according to an embodiment of the present application;

[0046] Fig.12is a schematic flow chart of an active alignment method according to another embodiment of the present application;

[0047] Fig.13 It is a flowchart of an image clarity evaluation method according to an embodiment of the present application. DETAILED DESCRIPTION

[0048] The following is a description of exemplary embodiments of the present application in conjunction with the accompanying drawings, including various details of the embodiments of the present application to facilitate understanding, which should be considered as merely exemplary. Therefore, it should be recognized by those of ordinary skill in the art that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the present application. Similarly, for the sake of clarity and conciseness, the description of well-known functions and structures is omitted in the following description.

[0049] In the drawings, the thickness, size and shape of the components have been slightly adjusted for ease of illustration. The drawings are for illustration only and are not drawn strictly to scale. As used herein, the terms "substantially," "approximately," and similar terms are used as terms of approximation, not as terms of degree, and are intended to account for the inherent deviations in measurements or calculations that would be recognized by one of ordinary skill in the art.

[0050] It should also be understood that expressions such as "include", "including", "have", "contain" and / or "comprising" are open rather than closed expressions in this specification, which indicate the presence of the stated features, elements and / or components, but do not exclude the presence of one or more other features, elements, components and / or combinations thereof. In addition, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire list of features rather than just the individual elements in the list. In addition, when describing embodiments of the present application, "may" is used to mean "one or more embodiments of the present application". And, the term "exemplary" is intended to refer to an example or illustration.

[0051] Unless otherwise specified, all words (including engineering terms and scientific and technological terms) used in this article have the same meaning as those commonly understood by ordinary technicians in the field to which this application belongs. It should also be understood that, unless clearly stated in this application, words defined in common dictionaries should be interpreted as having the same meaning as their meaning in the context of the relevant technology, and should not be interpreted in an idealized or overly formal sense.

[0052] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments in this application can be combined with each other. In addition, unless explicitly limited or contradictory to the context, the specific steps included in the method recorded in this application are not necessarily limited to the recorded order, but can be performed in any order or in parallel.

[0053] In addition, those skilled in the art will appreciate that the quantities shown in the drawings and below of the present application, such as the number of light films, are only shown for ease of illustration, and the specific quantities may be set according to actual needs without departing from the teachings of the disclosure of the present application.

[0054] AA technology is an assembly technology that uses precision automated assembly technology on the production line to automatically align the optical lens and the image sensor chip, so that the center of the optical lens and the center of the image sensor chip are located on the same axis perpendicular to the focal plane as much as possible, and the image sensor chip is located on the focal plane of the optical lens and parallel to the optical lens, so as to obtain the best image quality. The application of AA technology can greatly improve the clarity of the camera, the accuracy of the optical axis alignment, and reduce the tilt of the focal plane, thereby improving the image acquisition quality and consistency of the camera and obtaining higher assembly performance.

[0055] Figure 1 FIG. 1 is a schematic diagram showing an implementation method of the existing active alignment technology. Figure 1 As shown, the existing AA technology usually uses the imaging position of the feature point of the test pattern in the central area of ​​the test target 101, such as a knife edge, a slit or a line pair, to calculate the deviation between the center of the optical lens 102 and the center of the image sensor chip 103, and performs optical center alignment according to the deviation; by adjusting the position of the optical lens 102 along the optical axis, and recording the position of the optical lens after each adjustment and the photo 105 taken of the test target 101 at the position, the image quality index of the preset local measurement area of ​​the image and the image quality index of the central area of ​​the image are calculated according to all the obtained photos 105, and the defocus curve is obtained, and then the tilt of the optical lens 102 is corrected according to the best image plane fitting by the least square method.

[0056] like Figure 1 As shown, the above-mentioned existing AA technology needs to be equipped with a high-precision test target 101 when being implemented, and the image sensor chip 103 needs to be connected to the power supply 104 for powering on, and the optical lens 102 needs to be tested and adjusted multiple times to complete the alignment of the focal plane. Therefore, the existing AA technology has the following disadvantages:

[0057] 1. Chip 103 must be powered on, and the equipment needs to add relevant automatic plug-in devices such as power supply and data transmission. After each chip 103 is loaded, the automatic plug-in device must be controlled to connect the power supply and communication before the computer can drive the chip 103 and collect images through USB, network card and other communication methods. The connection of the automatic plug-in device will affect the efficiency of AA, making the efficiency of AA lower.

[0058] 2. When different chips 103 are involved, matching control programs need to be developed for different drivers. The development of control programs for different chips 103 will affect the versatility of AA development, making AA less versatile and increasing the corresponding development costs.

[0059] 3. A high-precision test target 101 must be provided. In addition to increasing the corresponding cost, the provision of a high-precision test target 101 also involves the universality issue that different test targets 101 need to be provided for different products.

[0060] In order to solve the above problems, an embodiment of the present application provides an active alignment device 1000 .

[0061] Figure 2 FIG. 1 is a block diagram of an active alignment device 1000 according to an embodiment of the present application. The active alignment device 1000 of the embodiment of the present application can be used to actively align a target lens with a target chip. Figure 2 As shown, the active alignment device 1000 may include: a reverse projection shooting module 100 and a processing control module 200. The reverse projection shooting module 100 is configured to reversely project a pixel image of the surface of the target chip through a target lens. The processing control module 200 is configured to control the active alignment of the target lens and the target chip according to the feature information of the target chip in the pixel image and the clarity information of the pixel image.

[0062] like Figure 3 As shown, the active alignment device 1000 of the embodiment of the present application adopts the reverse projection visual shooting technology to actively align the target lens 310 and the target chip 320. The reverse projection shooting module 100 reversely projects the surface of the target chip 320 through the target lens 310 to obtain the pixel image 330 on the surface of the target chip 320. The processing control module 200 detects the optical center deviation between the center of the target lens 310 and the center of the target chip 320 according to the feature information of the surface of the target chip 320 in the pixel image 330 shot by reverse projection, detects the tilt angle of the target lens 310 and the target chip 320 according to the clarity information of the pixel image 330 shot by reverse projection, and controls the active alignment of the target lens 310 and the target chip 320 according to the detected optical center deviation and tilt angle.

[0063] The active alignment device 1000 of the embodiment of the present application actively aligns the target lens 310 and the target chip 320 by adopting the reverse projection visual shooting technology. There is no need to power on and connect the target chip 320 for communication, which can save the time of connecting the target chip 320 with automatic plug-in devices such as power supply and data transmission, improve the efficiency of AA, and can be applied to AA scenarios that do not support powered imaging; it can be compatible with different target chips 320, and there is no need to develop supporting control programs for drivers of different target chips 320, so it has strong versatility and can save a lot of development time and cost; at the same time, by directly obtaining the pixel features on the surface of the target chip 320 as a test target, there is no need for additional high-precision customized test targets, which can save costs and has strong versatility.

[0064] It should be noted that the reverse projection shooting module 100 in the implementation manner of the present application can be an independent imaging device, such as a camera, a camcorder, etc., or it can be a non-independent photographic module, a video module, etc. The implementation manner of the present application does not limit the form of the reverse projection shooting module 100.

[0065] It should be noted that the processing control module 200 in the implementation manner of the present application can be implemented by software, or by a combination of software and hardware. The implementation manner of the processing control module 200 is not limited in the implementation manner of the present application.

[0066] It should be understood that the target lens 310 and the target chip in the embodiments of the present application may be an optical lens and an image sensor chip in a camera and / or a lidar, and the camera and / or lidar may be applied to fields such as autonomous driving.

[0067] In some optional embodiments of the present application, the pixel image 330 of the surface of the target chip 320 photographed by the reverse projection shooting module 100 through the target lens 310 may include a first pixel image and a second pixel image. Among them, the first pixel image may be a pixel image of the surface of the target chip 320 photographed by the reverse projection shooting module 100 through the target lens 310 at a certain position when the target lens 310 is in a stationary state. The second pixel image may be a group of pixel images of the surface of the target chip 320 photographed by the reverse projection shooting module 100 through the target lens 310 at several positions along the optical axis when the target lens 310 moves along the optical axis. Therefore, the reverse projection shooting module 100 can be configured to reversely project the first pixel image of the surface of the target chip 320 through the target lens 310; and reversely project the second pixel image of the surface of the target chip 320 through the target lens 310 during the movement of the target lens 310 along the optical axis.

[0068] Alternatively, if Figure 4As shown, the processing control module 200 may include: an image processing unit 210 and a motion control unit 220. The image processing unit 210 may be configured to detect the center deviation between the target lens 310 and the target chip 320 according to the feature information of the surface of the target chip 320 in the first pixel image; and to detect the tilt angle between the target lens 310 and the target chip 320 according to the clarity information of the second pixel image. The motion control unit 220 may be configured to control the target lens 310 to move along the optical axis; and to control the target lens 310 to move and actively align with the target chip 320 according to the center deviation and the tilt angle.

[0069] like Figure 3 As shown, when the active alignment device 1000 of the embodiment of the present application actively aligns the target lens 310 and the target chip 320, the reverse projection shooting module 100 can first reversely project the first pixel image of the surface of the target chip 320 through the target lens 310. Then, the image processing unit 210 detects the optical center deviation between the center of the target lens 310 and the center of the target chip 320 according to the feature information of the surface of the target chip 320 in the first pixel image captured by the reverse projection shooting module 100. Then, the motion control unit 220 controls the target lens 310 to move along its optical axis for defocusing, and reversely projects the second pixel image of the surface of the target chip 320 through the target lens 310 during the movement of the target lens 310 along the optical axis through the reverse projection shooting module 100. Then, the image processing unit 210 detects the tilt angle of the target lens 310 and the target chip 320 according to the clarity information of the second pixel image captured by the reverse projection shooting module 100, combined with the imaging clarity defocus curve. Finally, the motion control unit 220 controls the movement of the target lens 310 according to the optical center deviation and the tilt angle detected by the image processing unit 210 to achieve active alignment with the target chip 130 .

[0070] The active alignment device 1000 provided in the implementation manner of the present application will be described below with reference to the accompanying drawings in combination with specific embodiments.

[0071] In some optional embodiments of the present application, such as Figure 5As shown, the reverse projection shooting module 100 may include: an industrial camera 110 and a coaxial light source 120. The coaxial light source 120 is coaxially installed with the industrial camera 110 in front of the industrial camera 110. The industrial camera 110 is configured to shoot a pixel image 330 of the surface of the target chip 320 illuminated by the coaxial light source 120 through the target lens 310 by reverse projection. The industrial camera 110 and the coaxial light source 120 are combined in the reverse projection shooting module 100. By controlling the brightness of the coaxial light source 120, the surface of the target chip 320 at the field of view position that the industrial camera 110 needs to shoot can be illuminated, and the shooting of the pixels on the surface of the target chip 320 in a dark and closed environment can be achieved.

[0072] Optionally, the industrial camera 110 can adopt infinite reverse projection visual shooting, and the industrial camera 110 can be configured to shoot the pixel image 330 on the surface of the target chip 320 illuminated by the coaxial light source 120 through the target lens 310 reverse projection in the infinite shooting mode. Among them, the infinite shooting mode is that the object distance of the lens of the industrial camera 110 is infinite, and the adjustment method of the infinite object distance of the lens of the industrial camera 110 includes: firstly, the industrial camera 110 is aimed at the target in the collimator, and the target in the collimator can be regarded as being at infinity, and then the focus ring of the industrial camera 110 is adjusted to adjust the object distance of the lens from near to infinity, and the focus ring is fixed at the highest clarity. After the industrial camera 110 is set to the infinite shooting mode, the coaxial light source 120 with adjustable brightness is installed to the front end of the industrial camera 110, and the two are ensured to be coaxial by a fixture. Then, the shooting angle of the combination of the industrial camera 110 and the coaxial light source 120 is adjusted to be aimed at a certain area of ​​the target chip 320, and the pixel image 330 of the corresponding area can be obtained by reverse projection visual shooting. By adjusting the industrial camera 110 to the infinite shooting mode, a conjugate system is formed with the target lens 310, and the object distance of the conjugate system can be any value. At this time, the industrial camera 110 can capture the pixel features on the surface of the target chip 320 through the target lens 310.

[0073] Optionally, when the industrial camera 110 adopts infinite reverse projection visual shooting, the effective focal length EFL1 of the industrial camera 110 and the effective focal length EFL2 of the target lens 310 can satisfy: 3mm≤EFL1 / EFL2≤50mm. In an optional example, 6mm≤EFL1 / EFL2≤25mm. For example, the effective focal length EFL1 of the industrial camera 110 is 35mm, and the effective focal length EFL2 of the target lens 310 is 3.31mm. By selecting an industrial camera 110 with a different effective focal length EFL1, the magnification of the conjugate system can be increased, so that an enlarged high-definition pixel image 330 of the surface of the target chip 320 can be captured.

[0074] Optionally, the industrial camera 110 can adopt limited-distance reverse projection visual shooting, and the industrial camera 110 can be configured to shoot the pixel image 330 of the surface of the target chip 320 illuminated by the coaxial light source 120 through the target lens 310 reverse projection in the limited-distance shooting mode. Among them, the limited-distance shooting mode is that the object distance of the lens of the industrial camera 110 is a fixed value, and the adjustment method of the limited-distance object distance of the lens of the industrial camera 110 includes: firstly, the industrial camera 110 is aimed at the target placed at a fixed object distance, and then the object distance of the lens is adjusted from near to infinity by adjusting the focus ring of the industrial camera 110, and the focus ring is fixed at the highest clarity. After the industrial camera 110 is set to the limited-distance shooting mode, the coaxial light source 120 with adjustable brightness is installed to the front end of the industrial camera 110, and the two are ensured to be coaxial by a fixture. Then the shooting angle of the combination of the industrial camera 110 and the coaxial light source 120 is adjusted to align with a certain area of ​​the target chip 320, and the pixel image 330 of the corresponding area can be obtained by reverse projection visual shooting. By adjusting the industrial camera 110 to the finite distance shooting mode, a conjugate system is formed with the target lens 310, and the object distance of the conjugate system can be the fixed value. At this time, the industrial camera 110 can capture the pixel features on the surface of the target chip 320 through the target lens 310.

[0075] In some other optional embodiments of the present application, the degree of black and white change of pixels in the pixel image 330 on the surface of the target chip 320 can be used as a criterion for determining image clarity. The image processing unit 210 can be configured to divide each second pixel image into a number of image units according to a certain unit size; determine the contrast of the image unit according to the gray value of the pixel in each image unit; and count the proportion of the number of image units in each second pixel image that is greater than a preset contrast threshold in all image units as the clarity information of the corresponding pixel image.

[0076] like Figure 6As shown, the image processing unit 210 can perform image segmentation according to a certain unit size on the entire surface imaging picture of the target chip 320 collected by the reverse projection shooting module 100, that is, the second pixel image, to obtain n small-screen image units 330a. Then, the black-and-white contrast of each image unit 330a is calculated according to the grayscale value of the pixel in each image unit 330a, wherein the contrast calculation formula is: contrast = (image grayscale maximum value - image grayscale minimum value) / (image grayscale maximum value + image grayscale minimum value). Afterwards, the black-and-white contrast of all n image units 330a can be arranged from low to high, wherein high black-and-white contrast means that the black-and-white contrast in the unit picture is obvious, such as image unit 330b, and low black-and-white contrast means that the black-and-white contrast in the unit picture is obvious, such as image unit 330c. Then, the number m of image units whose black-and-white contrast is greater than the preset contrast threshold in the n image units 330a can be counted, and the proportion of image units whose black-and-white contrast is greater than the preset contrast threshold in all image units, that is, m / n, can be calculated as a quantitative value for evaluating the clarity of the entire picture.

[0077] After completing the above steps, for all the second pixel images captured by the target lens 310 along the optical axis by moving the reverse projection shooting module 100, the maximum value of the quantization value is taken as the benchmark to normalize the quantization values ​​of all the second pixel images, and the clarity defocus curve of any field of view can be obtained. Among them, the normalization method: each quantization value / maximum value of the quantization value, the normalized clarity value range is between 0 and 1. The optimal image plane when the lens and the chip are defocused can be calculated based on the above defocus curve. In an optional example, the resolution of the entire second pixel image is 400,000 pixels, the unit size of the image segmentation is 8*8 pixels, the preset contrast threshold is contrast ≥50%, and the final clarity value range is between 0-1. The image processing unit 210 uses the degree of black-and-white change of pixels in the second pixel image on the surface of the target chip 320 as a criterion for determining image clarity. It can determine the position of the optimal image when defocused by identifying the area on the surface of the target chip 320 where the black-and-white contrast is obvious. By quantifying the second pixel image on the surface of the target chip 320, it can quantify the defocus curve of the image from blurry to clear and then to blurry again, thereby accurately locating the focal plane.

[0078] It should be noted that, in the embodiments of the present application, the size of the image unit 332a and the preset contrast threshold can select appropriate values ​​according to different products, and the embodiments of the present application do not limit this.

[0079] In some other optional embodiments of the present application, the reverse projection shooting module 100 may include: a plurality of industrial cameras 110 and a plurality of coaxial light sources 120. Among them, the plurality of coaxial light sources 120 are respectively installed coaxially with each industrial camera 110 in front of the plurality of industrial cameras 110. The industrial cameras 110 are configured to respectively shoot pixel images 330 of a plurality of areas on the surface of the target chip 320 illuminated by the coaxial light source 120 through the target lens 310 through reverse projection. The reverse projection shooting module 100 can realize the shooting of a plurality of areas on the surface of the target chip 320 by spatially arranging a plurality of sets of industrial cameras 110 and coaxial light sources 120, which is helpful to realize universal recognition when the chip sizes are different and the surface features are different.

[0080] It should be noted that in the embodiments of the present application, the number of industrial cameras 110 and coaxial light sources 120 included in the reverse projection shooting module 100 is not limited.

[0081] In an alternative example, FIG. 7A to FIG. 7C As shown, the reverse projection shooting module 100 includes: five industrial cameras 110 and five coaxial light sources 120. Each of the five industrial cameras 110 adopts infinite reverse projection visual shooting, and the five industrial cameras 110 respectively collect pixel images 331, 332, 333, 334, and 335 at the center and four corners of the surface of the target chip 320. The effective focal length EFL1 of the five industrial cameras 110 is 35 mm, the effective focal length EFL2 of the target lens 310 is 3.31 mm, and the field of view angle FOV of the four industrial cameras 110 that collect the pixel images of the four corners of the surface of the target chip 320 is 74°.

[0082] First, each industrial camera 110 lens can be adjusted to an infinite object distance. The specific method includes: first, the industrial camera 110 is aimed at the target in the collimator, and the target in the collimator can be regarded as being at infinity. Then, the focus ring of the industrial camera 110 is adjusted to adjust the object distance of the lens from near to infinity, and the focus ring is fixed at the highest clarity. Each industrial camera 110 is operated in this way. Then, the coaxial light source 120 with adjustable brightness can be installed at the front end of the industrial camera 110, and the coaxiality of the two can be ensured by a fixture. After that, the shooting angle of each combination of the industrial camera 110 and the coaxial light source 120 can be adjusted to align with the center and four corners of the surface of the target chip 320.

[0083] Then, the four industrial cameras 110 that collect pixel images of the four corners of the surface of the target chip 320 can be configured to respectively shoot first pixel images of the four corners of the surface of the target chip 320 illuminated by the coaxial light source 120 through the target lens 310 through reverse projection. The image processing unit 210 can be configured to determine the actual position of the target lens 310 and the center of the target chip 320 according to the position information of the four corners of the surface of the target chip 320 in the first pixel image, and determine the center deviation according to the actual position and the target position.

[0084] The four coaxial light sources 120 are respectively installed in front of the four industrial cameras 110 and coaxially with each industrial camera 110. The first pixel image includes: a pixel image 332 at the upper left corner of the chip surface, a pixel image 333 at the upper right corner of the chip surface, a pixel image 334 at the lower left corner of the chip surface, and a pixel image 335 at the lower right corner of the chip surface. The image processing unit 210 can obtain the coordinates of the four corners of the surface of the target chip 320 by performing feature recognition on the pixel images 332, 333, 334, and 335 at the four corners of the surface of the target chip 320, namely, the coordinate P1 of the image feature of the upper left corner of the chip, the coordinate P2 of the image feature of the upper right corner of the chip, the coordinate P3 of the image feature of the lower left corner of the chip, and the coordinate P4 of the image feature of the lower right corner of the chip; then, the actual coordinates Pactual of the center of the target lens 310 and the target chip 320 can be calculated according to the coordinates of the four corners of the surface of the target chip 320, and the calculation formula is: Pactual=(P1+P2+P3+P4) / 4; finally, the center deviation of the target lens 310 and the target chip 320 can be calculated according to the theoretical coordinates Ptarget of the center of the target lens 120 and the target chip 130 and the actual coordinates Pactual, and the calculation formula is: center deviation=Pactual-Ptarget.

[0085] By photographing the features of the four corners of the surface of the target chip 320 as targets for calculating the optical eccentricity, the offset of each of the four corner coordinates is calculated using image feature recognition technology, and then the offset of the optical center is calculated using the offset of the four corner coordinates. The optical eccentricity detection can be achieved without additional targets, thereby achieving optical center alignment between the target lens 310 and the target chip 320.

[0086] Afterwards, the motion control unit 220 may be configured to control the target lens 310 to move along the optical axis. The five industrial cameras 110 that collect pixel images of the surface center and four corners of the target chip 320 may be configured to respectively shoot second pixel images of the surface center and four corners of the target chip 320 illuminated by the coaxial light source 120 through the target lens 310 through reverse projection during the movement of the target lens 310 along the optical axis. The image processing unit 210 may be configured to determine the clearest position of the surface center and four corners of the target chip 320 according to the clarity information of each pixel image in the second pixel image, and determine the tilt angle according to the clearest position.

[0087] Among them, five coaxial light sources 120 are respectively installed coaxially with each industrial camera 110 in front of the five industrial cameras 110. The second pixel image includes: a pixel image 331 at the center of the chip surface, a pixel image 332 at the upper left corner of the chip surface, a pixel image 333 at the upper right corner of the chip surface, a pixel image 334 at the lower left corner of the chip surface, and a pixel image 335 at the lower right corner of the chip surface. The image processing unit 210 can obtain the pixel image with the highest clarity in each group of pixel images by performing clarity recognition on each pixel image in the five groups of pixel images 331, 332, 333, 334, and 335 at the center and four corners of the surface of the target chip 320; then, the clearest positions of the center and four corners of the surface of the target chip 320 can be determined based on the pixel image with the highest clarity in the five groups of pixel images; Figure 7C As shown, the clearest position at the center of the chip surface is position 10, the clearest position at the lower right corner of the chip surface is position 14, and the same is true for other chip surface areas, so it is not repeated here; finally, the defocus amount of the four corners of the target chip 320 surface relative to the center can be calculated based on the clearest positions at the center and four corners of the target chip 320 surface through the defocus curve, and the tilt angle of the target lens 310 and the target chip 320 can be further calculated. The image processing unit 210 can quantitatively evaluate the clarity value of each pixel image based on the degree of black and white change of pixels in each pixel image at the center and four corners of the target chip 320 surface.

[0088] By shooting the features of the center and four corners of the target chip 320 surface as targets for image clarity calculation, and using clarity recognition on the pixel images of the center and four corners of the chip surface, the defocus amount of each corner can be calculated, and the tilt angle can be further calculated. Clarity detection can be achieved without additional targets, thereby correcting the tilt of the focal plane of the target lens 310 and the target chip 320 and achieving focal plane alignment.

[0089] In another alternative example, if FIG. 8A to FIG. 8B As shown, the reverse projection shooting module 100 includes: five industrial cameras 110 and five coaxial light sources 120. Each of the five industrial cameras 110 uses finite distance reverse projection visual shooting, and the five industrial cameras 110 respectively collect pixel images 331, 332, 333, 334, and 335 of the center and four corners of the surface of the target chip 320. The process of realizing active alignment can be similar to FIG. 7A to FIG. 7C The examples shown are similar, and only the differences between the two are described below. For other similarities, please refer to FIG. 7A to FIG. 7C The description of the examples shown is therefore not repeated here.

[0090] Among them, the object distance of the conjugate system is 150mm, the effective focal length EFL1 of the industrial camera 110 is 50mm, the effective focal length EFL2 of the target lens 310 is 13.76mm, and the field of view angle FOV of the industrial camera 110 for collecting pixel images of the four corners of the surface of the target chip 320 is 12°. When each industrial camera 110 lens is adjusted to a finite object distance, the industrial camera 110 is firstly aimed at a target placed at a fixed object distance of 150mm, and then the object distance of the lens is adjusted from near to infinite by adjusting the focus ring of the industrial camera 110, and the focus ring is fixed at the highest clarity. Each industrial camera 110 is operated in this way.

[0091] In yet another alternative example, Fig.9A and Fig. 9B As shown, the reverse projection shooting module 100 includes: five industrial cameras 110 and five coaxial light sources 120. Each of the five industrial cameras 110 adopts infinite reverse projection visual shooting, and the five industrial cameras 110 respectively collect pixel images 331, 336, 337, 338, and 339 at the center and four sides of the surface of the target chip 320. The effective focal length EFL1 of the five industrial cameras 110 is 35 mm, the effective focal length EFL2 of the target lens 310 is 3.31 mm, the field of view angle FOV of the industrial camera 110 that collects the pixel images on the upper and lower sides of the surface of the target chip 320 is 32°, and the field of view angle FOV of the industrial camera 110 that collects the pixel images on the left and right sides of the surface of the target chip 320 is 60°. The process of realizing active alignment can be compared with FIG. 7A to FIG. 7C The examples shown are similar, and only the differences between the two are described below. For other similarities, please refer to FIG. 7A to FIG. 7C The description of the examples shown is therefore not repeated here.

[0092] After the industrial camera 110 and the coaxial light source 120 are installed, the shooting angle of each combination of the industrial camera 110 and the coaxial light source 120 is adjusted to be aligned with the center and four sides of the surface of the target chip 320 .

[0093] Then, the four industrial cameras 110 that collect pixel images of the four sides of the surface of the target chip 320 can be configured to respectively shoot first pixel images of the four sides of the surface of the target chip 320 illuminated by the coaxial light source 120 through the target lens 310 through reverse projection. The image processing unit 210 can be configured to determine the actual position of the target lens 310 and the center of the target chip 320 according to the position information of the four sides of the surface of the target chip 320 in the first pixel image, and determine the center deviation according to the actual position and the target position.

[0094] The first pixel image includes: a pixel image 336 on the left side of the chip surface, a pixel image 337 on the top side of the chip surface, a pixel image 338 on the right side of the chip surface, and a pixel image 339 on the bottom side of the chip surface. The image processing unit 210 can obtain the coordinates of the four sides of the target chip 320 surface by performing feature recognition on the pixel images 336, 337, 338, and 339 on the four sides of the target chip 320 surface, namely, the coordinate P5 of the image feature on the left side of the chip, the coordinate P6 of the image feature on the top side of the chip, the coordinate P7 of the image feature on the right side of the chip, and the coordinate P8 of the image feature on the bottom side of the chip; then, the actual coordinates PactualX and PactualY of the center of the target lens 310 and the target chip 320 can be calculated according to the coordinates of the four sides of the target chip 320 surface, and the calculation formula is: PactualX=(P1X+P3X) / 2, PactualY=(P2Y+P4Y) / 2; finally, the center deviation of the target lens 310 and the target chip 320 can be calculated according to the theoretical coordinates Ptarget and the actual coordinates Pactual of the center of the target lens 310 and the target chip 320, and the calculation formula is: Center deviation=Pactual-Ptarget.

[0095] By photographing the features of the four sides of the target chip 320 surface as targets for calculating the optical eccentricity, the image feature recognition technology is used to calculate the offset of each four-side coordinate, and then the offset of the optical center is calculated through the offset of the four-side coordinates. The optical eccentricity detection can be realized without additional targets, so that the optical center alignment of the target lens 310 and the target chip 320 can be achieved.

[0096] Afterwards, the five industrial cameras 110 that collect pixel images of the center and four sides of the surface of the target chip 320 can be configured to respectively shoot second pixel images of the center and four sides of the surface of the target chip 320 illuminated by the coaxial light source 120 through the target lens 310 through reverse projection during the movement of the target lens 310 along the optical axis. The image processing unit 210 can be configured to determine the clearest position of the center and four sides of the surface of the target chip 320 according to the clarity information of each pixel image in the second pixel image, and determine the tilt angle according to the clearest position.

[0097] The second pixel image includes: a pixel image 331 at the center of the chip surface, a pixel image 336 at the left side of the chip surface, a pixel image 337 at the top of the chip surface, a pixel image 338 at the right side of the chip surface, and a pixel image 339 at the bottom of the chip surface. The image processing unit 210 can obtain the pixel image with the highest clarity in each group of pixel images by performing clarity recognition on each pixel image in the five groups of pixel images 331, 336, 337, 338, and 339 at the center and four sides of the target chip 320 surface; then, the clearest position of the center and four sides of the target chip 320 surface can be determined according to the pixel image with the highest clarity in the five groups of pixel images; finally, according to the clearest position of the center and four sides of the target chip 320 surface, the defocus amount of the four sides of the target chip 320 surface relative to the center can be calculated through the defocus curve, and the tilt angle of the target lens 310 and the target chip 320 can be further calculated. The image processing unit 210 can quantitatively evaluate the clarity value of each pixel image according to the degree of black and white change of pixels in each pixel image at the center and four sides of the surface of the target chip 320.

[0098] By shooting the features of the center and four sides of the target chip 320 surface as targets for image clarity calculation, and using clarity recognition on the pixel images of the center and four sides of the chip surface, the defocus amount of each edge can be calculated, and the tilt angle can be further calculated. Clarity detection can be achieved without additional targets, thereby correcting the tilt of the focal plane of the target lens 310 and the target chip 320 and achieving focal plane alignment.

[0099] In another optional example of the present application, Fig. 10A and Fig. 10B As shown, the reverse projection shooting module 100 includes: five industrial cameras 110 and five coaxial light sources 120. Each of the five industrial cameras 110 uses finite distance reverse projection visual shooting, and the five industrial cameras 110 respectively collect pixel images 331, 336, 337, 338, and 339 of the center and four sides of the surface of the target chip 320. The process of realizing active alignment is similar to FIG. 9A to FIG. 9B The examples shown are similar, and only the differences between the two are described below. For other similarities, please refer to FIG. 9A to FIG. 9B The description of the examples shown is therefore not repeated here.

[0100] The object distance of the conjugate system is 150 mm, the effective focal length EFL1 of the industrial camera 110 is 50 mm, and the effective focal length EFL2 of the target lens 310 is 13.76 mm. When adjusting each lens of the industrial camera 110 to a finite object distance, firstly align the industrial camera 110 with a target placed at a fixed object distance of 150 mm, and then adjust the focus ring of the industrial camera 110 so that the object distance of the lens is from near to infinite, and fix the focus ring at the highest clarity. Each industrial camera 110 is operated in this way.

[0101] The embodiment of the present application also provides an active alignment method 2000, Fig.11 FIG. 2 is a flow chart of an active alignment method 2000 according to an embodiment of the present application. The active alignment device 1000 of any of the above embodiments of the present application can execute the active alignment method 2000, and the active alignment method 2000 is applied to actively align a target lens with a target chip. Fig.11 As shown, the active alignment method 2000 may include the following steps: S400, photographing a pixel image of the target chip surface through reverse projection of the target lens. S500, controlling the target lens to actively align with the target chip according to the feature information of the target chip surface in the pixel image and the clarity information of the pixel image.

[0102] It should be understood that the steps shown in method 2000 are not exclusive, and other steps may be performed before, after, or between any of the steps shown. In addition, some of the steps shown may be performed simultaneously, or may be performed in different steps. Figure 1 Executed in the order shown.

[0103] Alternatively, if Fig.12 As shown, step S400 may include: S410, photographing a first pixel image of the surface of the target chip through reverse projection of the target lens. S420, controlling the target lens to move along the optical axis, and photographing a second pixel image of the surface of the target chip through reverse projection of the target lens during the movement of the target lens along the optical axis.

[0104] Alternatively, if Fig.12 As shown, step S500 may include: S510, detecting the center deviation between the target lens and the target chip according to the feature information of the target chip surface in the first pixel image. S520, detecting the tilt angle between the target lens and the target chip according to the clarity information of the second pixel image. S530, controlling the target lens to move and actively align with the target chip according to the center deviation and the tilt angle.

[0105] Alternatively, if Fig.13As shown, step S520 may include: S521, dividing each second pixel image into a plurality of image units according to a certain unit size. S522, determining the contrast of the image unit according to the gray value of the pixel in each image unit. S523, counting the proportion of the number of image units greater than a preset contrast threshold in each second pixel image in all image units as the clarity information of the corresponding second pixel image.

[0106] Optionally, step S400 may include: photographing a pixel image of the surface of the target chip illuminated by a coaxial light source by reverse projection through the target lens with an industrial camera, wherein the coaxial light source is installed coaxially with the industrial camera in front of the industrial camera.

[0107] Optionally, photographing the pixel image of the target chip surface illuminated by the coaxial light source by reverse projection through the target lens by the industrial camera may include: photographing the pixel image of the target chip surface illuminated by the coaxial light source by reverse projection through the target lens by the industrial camera in infinite shooting mode.

[0108] Optionally, the effective focal length EFL1 of the industrial camera and the effective focal length EFL2 of the target lens satisfy: 3mm≤EFL1 / EFL2≤50mm.

[0109] Optionally, photographing the pixel image of the target chip surface illuminated by the coaxial light source by reverse projection through the target lens by the industrial camera may include: photographing the pixel image of the target chip surface illuminated by the coaxial light source by reverse projection through the target lens by the industrial camera in a finite distance shooting mode.

[0110] Optionally, photographing the pixel image of the target chip surface illuminated by the coaxial light source by reverse projection through the target lens by an industrial camera may include: photographing the pixel images of several areas of the target chip surface illuminated by the coaxial light source by reverse projection through the target lens by several industrial cameras respectively, wherein several coaxial light sources are respectively installed coaxially with each of the industrial cameras in front of the several industrial cameras.

[0111] Optionally, the method may include: using the four industrial cameras to respectively shoot first pixel images of the four corners of the target chip surface illuminated by the coaxial light source through the target lens and reverse projection, wherein four coaxial light sources are respectively installed coaxially with each of the four industrial cameras in front of the four industrial cameras; determining the actual position of the target lens and the center of the target chip according to the position information of the four corners of the target chip surface in the first pixel image, and determining the center deviation according to the actual position and the target position.

[0112] Optionally, the method may include: controlling the target lens to move along the optical axis, and in the process of the target lens moving along the optical axis, using the five industrial cameras to respectively shoot the second pixel images of the center and four corners of the target chip surface illuminated by the coaxial light source through the target lens and reverse projection, wherein five coaxial light sources are respectively installed coaxially with each of the five industrial cameras in front of the five industrial cameras; determining the clearest positions of the center and four corners of the target chip surface according to the clarity information of each pixel image in the second pixel image, and determining the inclination angle according to the clearest position.

[0113] Optionally, the method may include: using the four industrial cameras to respectively shoot, through the target lens and reversely project, the first pixel images of the four sides of the target chip surface illuminated by the coaxial light source, wherein four coaxial light sources are respectively installed coaxially with each of the industrial cameras in front of the four industrial cameras; determining the actual position of the target lens and the center of the target chip according to the position information of the four sides of the target chip surface in the first pixel image, and determining the center deviation according to the actual position and the target position.

[0114] Optionally, the method may include: controlling the target lens to move along the optical axis, and in the process of the target lens moving along the optical axis, using the five industrial cameras to respectively shoot the second pixel images of the center and four sides of the target chip surface illuminated by the coaxial light source through the target lens and reverse projection, wherein five coaxial light sources are respectively installed coaxially with each of the five industrial cameras in front of the five industrial cameras; determining the clearest positions of the center and four sides of the target chip surface according to the clarity information of each pixel image in the second pixel image, and determining the inclination angle according to the clearest position.

[0115] The above specific implementations do not constitute a limitation on the protection scope of the present disclosure. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present disclosure shall be included in the protection scope of the present disclosure.

Claims

1. An active alignment device, characterized in that: Applicable to actively calibrate a target lens and a target chip, the device comprises: A reverse projection shooting module is configured to shoot a pixel image of the surface of the target chip through reverse projection of the target lens; and The processing control module is configured to control the target lens to actively align with the target chip according to the feature information of the target chip in the pixel image and the clarity information of the pixel image.

2. The device according to claim 1, characterized in that The reverse projection shooting module is configured to shoot a first pixel image on the surface of the target chip through reverse projection of the target lens; and shoot a second pixel image on the surface of the target chip through reverse projection of the target lens during the movement of the target lens along the optical axis.

3. The device according to claim 2, characterized in that The processing control module comprises: an image processing unit, configured to detect a center deviation between the target lens and the target chip according to feature information of the surface of the target chip in the first pixel image; detect a tilt angle between the target lens and the target chip according to clarity information of the second pixel image; and The motion control unit is configured to control the target lens to move along the optical axis; and control the target lens to move and actively align with the target chip according to the center deviation and the tilt angle.

4. The device according to claim 3, characterized in that The image processing unit is configured to divide each of the second pixel images into a plurality of image units according to a certain unit size; and determine the contrast of the image unit according to the grayscale value of the pixel in each of the image units; And the proportion of the number of image units of each second pixel image that is greater than a preset contrast threshold in all image units is counted as the clarity information of the corresponding pixel image.

5. The device according to claim 3 or 4, characterized in that The reverse projection shooting module comprises: an industrial camera configured to capture a pixel image of the surface of the target chip illuminated by a coaxial light source through reverse projection of the target lens; and The coaxial light source is installed coaxially with the industrial camera in front of the industrial camera.

6. The device according to claim 5, characterized in that The industrial camera is configured to shoot a pixel image of the surface of the target chip illuminated by the coaxial light source through the target lens and reverse projection in an infinite shooting mode.

7. The device according to claim 6, characterized in that The effective focal length EFL1 of the industrial camera and the effective focal length EFL2 of the target lens satisfy: 3mm≤EFL1 / EFL2≤50mm.

8. The device according to claim 5, characterized in that The industrial camera is configured to shoot a pixel image of the surface of the target chip illuminated by the coaxial light source through the target lens and reverse projection in a limited distance shooting mode.

9. The device according to any one of claims 6 to 8, characterized in that The reverse projection shooting module comprises: The plurality of industrial cameras are configured to respectively capture pixel images of a plurality of regions on the surface of the target chip illuminated by the coaxial light source through reverse projection of the target lens; and The plurality of coaxial light sources are respectively installed coaxially with the plurality of industrial cameras in front of the plurality of industrial cameras.

10. An active alignment method, characterized in that: Applied to actively align a target lens with a target chip, the method comprises: photographing a pixel image of the surface of the target chip through reverse projection of the target lens; and According to the feature information of the surface of the target chip in the pixel image and the clarity information of the pixel image, the target lens is controlled to be actively aligned with the target chip.

Images