Optical magnification image acquisition system and welding spot detection method

Abstract

The invention belongs to the technical field of welding spot detection, and discloses an optical magnification image acquisition system and a welding spot detection method.The optical magnification image acquisition system comprises an optical magnification instrument, a movable objective table and a light path guide assembly; the movable objective table is perpendicular to the optical axis of the optical amplification instrument and can move in the vertical direction of the optical axis. The light path guiding assembly comprises a primary reflector and a secondary reflector. The primary reflector is used for reflecting reflected light of the top surface and the side surface of a sampling point of a sample on the movable objective table to the secondary reflector; and the secondary reflector is used for reflecting the reflected light into the objective lens of the optical amplification instrument again. A welding spot is used as a sampling point, and an image of the welding spot on a flat sample is acquired by adopting the optical magnification image acquisition system. The step of focusing by frequently adjusting the height of the objective lens is omitted, automatic scanning can be achieved, and the detection efficiency is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of solder joint detection, and in particular relates to an optical magnification image acquisition system and a solder joint detection method. Background Art

[0002] During the product design verification test phase of the electronic controller, the product needs to be tested for solder joint aging after the full life test is completed to ensure that the product solder joints still have a certain life margin to ensure product reliability.

[0003] During the inspection, the front and side of each solder joint must be visually inspected under a microscope. Therefore, the optical magnifying instrument can only observe the solder joints when the circuit board (PCB) is tilted. The object distance from different solder joints to the optical magnifying instrument is different, and different objective lens heights need to be adjusted for focusing on different solder joints. This inspection method requires the operator to move the stage and adjust the objective lens height of the optical magnifying instrument at the same time. The operation is very cumbersome, the workload is large, and the inspection efficiency is low. Summary of the invention

[0004] The present application provides an optical magnification image acquisition system to solve the technical problems of complicated operation and low detection efficiency.

[0005] The present invention is implemented by the following technical scheme: an optical magnification image acquisition system, comprising:

[0006] Optical magnification instruments, movable stages and light path guide components;

[0007] The movable stage is perpendicular to the optical axis of the optical magnifying instrument and can move along the perpendicular direction of the optical axis;

[0008] The optical path guiding assembly includes a primary reflector and a secondary reflector;

[0009] The primary reflector is located outside the projection of the secondary reflector along the optical axis, and the secondary reflector is located between the optical magnifying instrument and the movable stage and intersects the optical axis;

[0010] The primary reflector is used to reflect the reflected light from the side surface or top surface and the side surface of the sampling point of the sample on the movable stage to the secondary reflector;

[0011] The secondary reflector is used to reflect the reflected light again into the optical magnifying instrument.

[0012] The optical path guide assembly of the present invention can collect the reflected light from the top and side surfaces of the sample at the same time through the primary reflector, so there is no need to tilt the sample itself; the secondary reflector then reflects the reflected light into the optical magnifying instrument, and the object distance from the secondary reflector to the optical magnifying instrument will not change with the horizontal movement of the sample. Then, after the objective lens has focused on the secondary reflector, any horizontal movement of the sample can ensure focus, thereby obtaining a clear operation that can simultaneously display the object distance of the top and side surfaces of the sampling point.

[0013] Furthermore, the primary reflector is parallel to the optical axis, so as to better take into account the collection of reflected light from the side and top surfaces, and avoid the loss of reflected light from one of the surfaces.

[0014] Furthermore, the angle between the secondary reflector and the optical axis is greater than 0° and less than 90°, so as to avoid the angle of the secondary reflector being too steep to reflect the reflected light to the optical magnifying instrument again, and to avoid the angle of the secondary reflector being too flat to receive the reflected light.

[0015] Furthermore, it also includes a controller, which is used to control the horizontal movement of the movable stage according to the scanning path so that the sampling points on the sample are located on the optical axis of the optical magnifying instrument in sequence.

[0016] The controller controls the horizontal movement of the movable stage according to the scanning path to realize automatic acquisition.

[0017] Furthermore, the scanning path is the shortest path including all sampling points. The shorter the scanning path, the higher the scanning efficiency.

[0018] Furthermore, the controller is used to control the intermittent movement of the movable stage according to the relative displacement of the coordinates of adjacent points on the scanning path.

[0019] Intermittent movement means pausing after each movement to observe or take pictures of the sampling points.

[0020] Furthermore, it also includes an image sensor, and the controller is used to control the image sensor to take pictures of sampling points on the optical axis reaching the optical magnifying instrument, and associate the coordinates of the sampling points in the sample coordinate system with the sampling point image.

[0021] After the sampling point image is associated with the coordinates, it is helpful to quickly locate each sampling point through the sampling point image, which is convenient for analysis and backtracking.

[0022] Furthermore, the controller is used to upload the sampling point images associated with the sampling point coordinates to the host computer.

[0023] After the sampling point image is uploaded to the host computer, the sampling point can be observed remotely through the image, without directly observing the optical magnifying instrument, avoiding visual fatigue and other physical discomfort caused by long-term use of the optical magnifying instrument. Efficiency can also be further improved by having multiple people observe images of different sampling points at the same time.

[0024] The present invention also provides a welding spot detection method, which uses the welding spots as sampling points and adopts the above-mentioned optical magnification image acquisition system to acquire images of the welding spots on the flat sample.

[0025] Further, the following steps are included:

[0026] Placing a flat sample on the movable stage and placing the first welding point on the scanning path at a target position;

[0027] Adjusting the primary reflector and the secondary reflector in the optical path guide assembly so that the primary reflector can collect reflected light from the top surface and the side surface of the first solder joint, and the secondary reflector can reflect the reflected light again along the optical axis of the optical magnifying instrument into the optical magnifying instrument;

[0028] Adjust the object distance from the optical magnifying instrument to the secondary reflector so that the first solder joint is clearly displayed;

[0029] The controller controls the movable stage to move according to the scanning path so that the remaining welding points are located on the optical axis of the optical magnifying instrument in sequence.

[0030] Furthermore, the flat sample is a circuit board.

[0031] The optical magnification image acquisition system of the present invention can acquire images of different sampling points at the same object distance, eliminating the step of frequently adjusting the height of the optical magnification instrument to focus on different sampling points. By adding a controller to control the movable stage to move according to the scanning path for automatic scanning, the detection efficiency is greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0033] Figure 1 It is a schematic diagram of the operation of solder joint detection in the prior art.

[0034] Figure 2 Schematic diagram of the operation of solder joint detection according to this specific implementation method. DETAILED DESCRIPTION

[0035] In the existing technology, the solder joint detection operation is very cumbersome, the workload is large, and the detection efficiency is low. Figure 1 As shown, in the solder joint inspection work, the front and side of each solder joint need to be visually inspected under a microscope, so the PCB board 5 needs to be placed on the tilting fixture 201, which leads to inconsistent heights of the solder joints on the PCB. When inspecting different solder joints, not only the stage 202 needs to be moved horizontally, but also the object distance from the optical magnifying instrument 101 to the solder joint needs to be adjusted for focusing. For example, from observing point A on the PCB to observing point B, since the vertical height of point B is lower than that of point A, after moving point B to the optical axis of the optical magnifying instrument, the object distance from the optical magnifying instrument to point B is greater than the object distance h1 from the optical magnifying instrument to point A, and the optical magnifying instrument needs to be lowered by h2 so that the object distance from the optical magnifying instrument to point B is adjusted to h1 to maintain a clear focal length for imaging.

[0036] In order to simplify the operation and improve the detection efficiency, this specific implementation provides an optical magnification image acquisition system. Figure 2 As shown, including:

[0037] An optical magnifying instrument 1, a movable stage 2 and an optical path guiding assembly;

[0038] The movable stage is perpendicular to the optical axis of the optical magnifying instrument and can move along the perpendicular direction of the optical axis;

[0039] The optical path guiding assembly includes a primary reflector 3 and a secondary reflector 4;

[0040] The primary reflector is located outside the projection of the secondary reflector along the optical axis, and the secondary reflector is located between the optical magnifying instrument and the movable stage and intersects the optical axis;

[0041] The primary reflector is used to reflect the reflected light from the side surface or top surface and the side surface of the sampling point of the sample on the movable stage to the secondary reflector;

[0042] The secondary reflector is used to reflect the reflected light again into the optical magnifying instrument.

[0043] The optical path guide assembly of this specific embodiment can collect the reflected light from the top and side of the sample at the same time through the primary reflector, so there is no need to tilt the sample itself; the secondary reflector then reflects the reflected light into the optical magnifying instrument, and the object distance from the secondary reflector to the optical magnifying instrument will not change with the horizontal movement of the sample. Then, after the objective lens has focused on the secondary reflector, any horizontal movement of the sample can ensure focus, thereby obtaining a clear operation that can simultaneously display the object distance of the top and side of the sampling point.

[0044] In this specific implementation, the movable stage is arranged in the horizontal direction. Of course, the movable stage can also be arranged in the vertical direction as required, as long as the optical axis of the optical magnifying instrument is perpendicular to the movable stage.

[0045] In this specific implementation, the primary reflector is parallel to the optical axis, which can better take into account the collection of reflected light from the side and top surfaces, avoiding the loss of reflected light from one of the surfaces. Of course, the primary reflector can also be set to collect only the side of the sampling point as needed.

[0046] In this specific implementation, the angle between the secondary reflector and the optical axis is greater than 0° and less than 90°, so as to avoid the angle of the secondary reflector being too steep to reflect the reflected light to the optical magnifying instrument again, and to avoid the angle of the secondary reflector being too flat to receive the reflected light.

[0047] In this specific embodiment, a controller 6 is also included, and the controller 6 is used to control the movable stage 2 to move along the perpendicular direction of the optical axis according to the scanning path so that the sampling points on the sample are located at the target positions in sequence; the target position refers to the position that can ensure that the primary reflector can obtain the reflected light from the top and side surfaces of the sampling points.

[0048] In the case of opaque samples, the sample point at the target position can be illuminated by side lighting. The target position can be set on the optical axis or off the optical axis, which is the axis through the center of the field of view of the optical magnifying instrument.

[0049] In this specific implementation, the scanning path is the shortest path including all sampling points. The shorter the scanning path, the higher the scanning efficiency. The shortest path can be obtained by connecting adjacent sampling points in sequence.

[0050] In this specific implementation, the controller is used to control the intermittent movement of the movable stage according to the relative displacement of the coordinates of adjacent points on the scanning path. Intermittent movement means pausing after each movement is completed so as to observe or take pictures of the sampling points.

[0051] In this specific implementation, an image sensor is also included, and the controller is used to control the image sensor to take pictures of the sampling points that have reached the target position, and associate the coordinates of the sampling points in the sample coordinate system with the sampling point image.

[0052] After the sampling point image is associated with the coordinates, it is helpful to quickly locate each sampling point through the sampling point image, which is convenient for analysis and backtracking.

[0053] In this specific implementation, the controller is used to upload the sampling point images associated with the sampling point coordinates to the host computer.

[0054] After the sampling point image is uploaded to the host computer, the sampling point can be observed remotely through the image, without directly observing the optical magnifying instrument, avoiding visual fatigue and other physical discomfort caused by long-term use of the optical magnifying instrument. Efficiency can also be further improved by having multiple people observe images of different sampling points at the same time.

[0055] This specific embodiment also provides a welding spot detection method, which uses welding spots as sampling points and uses the optical magnification image acquisition system in this specific embodiment to acquire images of welding spots on flat samples.

[0056] In this specific implementation, the optical magnifying instrument is a microscope. The optical magnifying instrument can also be a magnifying glass, which is fixed by a height-adjustable bracket, and the object distance can be adjusted by adjusting the height of the bracket.

[0057] In this specific implementation, the flat sample is a PCB board, and of course it can also be other flat parts with solder joints.

[0058] Specifically, the following steps are included:

[0059] refer to Figure 2 As shown, a flat sample is placed on the movable stage, and the first welding point on the scanning path is placed on the target position. In this embodiment, the target position is set on the optical axis of the microscope.

[0060] refer to Figure 2 As shown in (a), the primary reflector 3 and the secondary reflector 4 in the optical path guiding assembly are adjusted so that the primary reflector 3 can collect the reflected light from the top surface and the side surface of the first solder joint 501, and the secondary reflector 4 can reflect the reflected light along the optical axis of the optical magnifying instrument 1 again into the optical magnifying instrument.

[0061] Adjust the object distance h from the optical magnifying instrument to the secondary reflector so that the first solder joint 501 is clearly displayed; at this time, a start scanning instruction can be sent to the controller, and the start scanning instruction can be sent to the controller through a button switch or a host computer. After receiving the start scanning instruction, the controller controls the image sensor 7 to take pictures, and the image sensor takes pictures facing the eyepiece to obtain the optically magnified image of the first solder joint after magnification, and sends the optically magnified image of the first solder joint to the controller, and the controller associates the coordinate position of the first solder joint 501 in the PCB board coordinate system with the optically magnified image of the first solder joint and sends it to the host computer. The coordinate position of the first solder joint 501 can be set as the origin, so as to calculate the coordinate positions of the remaining solder joints according to the relative positions.

[0062] refer to Figure 2As shown in (b), the controller 6 controls the movable stage to move according to the scanning path so that the remaining welding points are located at the target positions in sequence. For example, when the second welding point 502 is moved to the target position, there is no need to adjust the object distance h of the optical magnifying instrument. The controller controls the movable stage to stay for 1 to 3 seconds and controls the image sensor 7 to take pictures.

[0063] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection created by this application.

Claims

1. An optical magnification image acquisition system, characterized in that: include: Optical magnification instruments, movable stages and light path guide components; The movable stage is perpendicular to the optical axis of the optical magnifying instrument and can move along the perpendicular direction of the optical axis; The optical path guiding assembly includes a primary reflector and a secondary reflector; The primary reflector is located outside the projection of the secondary reflector along the optical axis, and the secondary reflector is located between the optical magnifying instrument and the movable stage and intersects the optical axis; The primary reflector is used to reflect the reflected light from the side surface or top surface and the side surface of the sampling point of the sample on the movable stage to the secondary reflector; The secondary reflector is used to reflect the reflected light again into the optical magnifying instrument.

2. The optical magnification image acquisition system according to claim 1, characterized in that: The primary reflection mirror is parallel to the optical axis.

3. The optical magnification image acquisition system according to claim 1, characterized in that: The angle between the secondary reflector and the optical axis is greater than 0° and less than 90°.

4. The optical magnification image acquisition system according to claim 1, characterized in that: It also includes a controller, which is used to control the movable stage to move along the perpendicular direction of the optical axis according to the scanning path so that the sampling points on the sample are located at the target positions in sequence; the target position refers to the position that can ensure that the primary reflector can obtain the reflected light from the top and side surfaces of the sampling points.

5. The optical magnification image acquisition system according to claim 4, characterized in that: The scanning path is the shortest path including all sampling points.

6. The optical magnification image acquisition system according to claim 4, characterized in that: The controller is used to control the intermittent movement of the movable stage according to the relative displacement of the coordinates of adjacent points on the scanning path.

7. The optical magnification image acquisition system according to claim 4 or 6, characterized in that: It also includes an image sensor, and the controller is used to control the image sensor to take pictures of the sampling points that have reached the target position, and associate the coordinates of the sampling points in the sample coordinate system with the sampling point image.

8. The optical magnification image acquisition system according to claim 7, characterized in that: The controller is used to upload the sampling point images associated with the sampling point coordinates to the host computer.

9. A solder joint detection method, characterized in that: The welding points are used as sampling points, and the optical magnification image acquisition system as claimed in any one of claims 4 to 8 is used to acquire images of the welding points on the flat sample.

10. The solder joint detection method according to claim 9, characterized in that: The following steps are involved: Placing a flat sample on the movable stage and placing the first welding point on the scanning path at a target position; Adjusting the primary reflector and the secondary reflector in the optical path guide assembly so that the primary reflector can collect reflected light from the top surface and the side surface of the first solder joint, and the secondary reflector can reflect the reflected light again along the optical axis of the optical magnifying instrument into the optical magnifying instrument; Adjust the object distance from the optical magnifying instrument to the secondary reflector so that the first solder joint is clearly displayed; The controller controls the movable stage to move according to the scanning path so that the remaining welding points are located on the optical axis of the optical magnifying instrument in sequence.

11. The solder joint detection method according to claim 9 or 10, characterized in that: The flat sample is a circuit board; the optical magnifying instrument is a microscope.

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