Via hole welding spot tin penetration depth detection device and method based on infrared thermal imaging

Abstract

The invention relates to the field of semiconductor circuit packaging detection, and discloses a via hole welding spot tin penetration depth detection device and method based on infrared thermal imaging, and the device comprises an excitation source unit, a control system, an infrared imager, and a tested piece. A plurality of via hole welding spots are distributed on the surface of the tested piece, the infrared imager and the excitation source unit are located on the two sides of the tested piece respectively, and the excitation source unit is used for heating the surface of the tested piece; a camera of the infrared imager is aligned with a plurality of via hole welding spots on the surface of the tested piece; the control end of the control system is respectively connected with the control ends of the infrared imager and the excitation source unit, the excitation source unit can quickly heat the surface of the test piece to be tested, the infrared imager can capture and record the temperature change in real time, and the captured image is fed back to the control system; and the tin penetration depth of the via hole welding spot is obtained through processing of the control system, so that the detection efficiency of the tin penetration depth of the via hole welding spot is effectively improved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor circuit packaging detection, and in particular to a device and method for detecting the tin penetration depth of a via solder joint based on infrared thermal imaging. Background Art

[0002] The tinning of circuit board vias (conducting holes) is a pre-manufacturing process for soldering electronic devices. Usually, after applying solder paste on one side of the circuit board, it is heated at high temperature to make the solder paste flow into the via in liquid form, which is convenient for subsequent device pin perforation and reflow soldering. Ideally, the tin should be filled in the via. However, in actual processing, the solder paste, flux, PCB material quality and heating process parameters will affect the amount of solder paste in the via. It is easy to cause problems such as cold soldering, tin cracking and shedding, affecting the welding quality of the PCB board and the device. Therefore, quantitative detection of the tinning depth of the via solder joint, that is, the degree to which the solder fills the pad or solder hole, is an important indicator for evaluating welding quality and reliability, and is closely related to the reliability and electrical performance of the product.

[0003] At present, the commonly used detection or quantification methods for tin penetration depth mainly include X-ray detection method and slice analysis method. Among them, the X-ray detection method mainly scans the PCB board under test through X-ray transmission or tomography to form a transmission two-dimensional image or a three-dimensional internal reconstruction image. Due to the risk of radioactive hazards to the human body caused by radiation, and the scanning time for reconstructing images by this type of method usually takes several hours, it is usually only possible to do sampling detection, and cannot achieve continuous detection of large quantities of products. The slice analysis method refers to grinding the sample layer by layer with a metallographic grinder after the device is solidified, and then observing the solder quality on the grinding surface of the via under a microscope. Although this method can provide intuitive internal data of the solder joint, it is destructive to the product and is only applicable to the analysis of the product processing technology. It cannot actually perform large-scale detection of the product. Summary of the invention

[0004] In order to overcome the defects of the above-mentioned prior art, the purpose of the present invention is to provide a device and method for detecting the tin penetration depth of a via solder joint based on infrared thermal imaging, so as to solve the technical problem of how to quantitatively detect the tin penetration depth in the prior art.

[0005] The present invention is achieved through the following technical solutions: In a first aspect, the present invention provides a via solder joint tin penetration depth detection device based on infrared thermal imaging, comprising an excitation source unit, a control system, an infrared imager and a test piece; A plurality of via-hole solder joints are distributed on the surface of the tested object, the infrared imager and the excitation source unit are respectively located on both sides of the tested object, and the excitation source unit is used to heat the surface of the tested object; the camera of the infrared imager is set to be aimed at a plurality of via-hole solder joints on the surface of the tested object; The control end of the control system is connected to the control end of the infrared imager and the excitation source unit respectively.

[0006] Preferably, the plate surface of the tested piece is arranged in parallel with the heating surface of the excitation source unit.

[0007] Preferably, a distance is provided between the tested piece and the infrared imager and the excitation source unit respectively.

[0008] Preferably, the bottom of the tested piece is placed on a fixed base.

[0009] Preferably, the control system includes a controller and a computer device; The driving end of the controller is connected to the excitation source unit, and the control end of the controller and the control end of the infrared imager are respectively connected to the computer device.

[0010] Furthermore, a control module is provided in the computer device, the input end of the control module is connected to the signal acquisition module, the input end of the signal acquisition module is connected to the infrared imager; the output end of the control module is connected to the signal output module, the output end of the signal output module is respectively connected to the processor and the controller; the driving end of the controller is connected to the excitation source unit.

[0011] In a second aspect, the present invention further provides a method for detecting the penetration depth of tin in a via-hole solder joint based on infrared thermal imaging, based on the above-mentioned device for detecting the penetration depth of tin in a via-hole solder joint based on infrared thermal imaging, comprising the following process: The control system drives the power of the excitation source unit to heat the area around the test piece to form a thermal environment; The infrared thermal imaging camera is aimed at the test piece to shoot, and the captured infrared image is transmitted to the control system; The control system processes and analyzes the captured infrared images to obtain the tin penetration depth of the via-hole solder joints.

[0012] Preferably, the control system performs data processing on the captured infrared images, and during the analysis, the control system performs denoising on the infrared image sequence, and performs data compression on the infrared image sequence, and calculates the tin penetration depth of the via-hole solder joint according to the compression result.

[0013] Furthermore, the specific process of calculating the tin penetration depth of the via solder joint according to the compression result is as follows: The signal difference captured by two frames of images at a unit time interval is taken as the calculation object, and the thermal radiation gradient per unit time is obtained through mapping based on the signal difference. Then, the time series window is slid to calculate the time series thermal radiation gradient of multiple frames of images in a continuous unit time. Finally, the time series thermal radiation gradient is weighted and averaged to obtain the thermal imaging image of the workpiece under test characterized by the temperature change rate.

[0014] Furthermore, the specific process of calculating the tin penetration depth of the via solder joint according to the compression result is as follows: Based on the premise that the physical properties of the material of the workpiece under test change with temperature within a temperature dynamic range, polynomial fitting is performed according to the temperature change curve of fixed pixel points in multi-frame time-series infrared images, and the thermal imaging image of the workpiece under test characterized by the temperature change rate is constructed using the fitting coefficients.

[0015] Compared with the prior art, the present invention has the following beneficial technical effects: The present invention provides a device for detecting the tin penetration depth of a via-hole solder joint based on infrared thermal imaging, wherein an infrared imager and an excitation source unit are respectively located on two sides of a tested piece, the excitation source unit is used to heat the surface of the tested piece; a camera of the infrared imager is aimed at a plurality of via-hole solder joints on the surface of the tested piece; the surface of the tested piece can be quickly heated by the excitation source unit, and the infrared imager can capture and record temperature changes in real time, and feed the captured image back to a control system, and the tin penetration depth of the via-hole solder joint is obtained through processing by the control system, thereby effectively improving the detection efficiency of the tin penetration depth of the via-hole solder joint.

[0016] Furthermore, the plate surface of the test piece is arranged parallel to the heating surface of the excitation source unit, and a distance is provided between the test piece and the infrared imager and the excitation source unit respectively. The excitation source introduces or generates heat in infrared thermal imaging, thereby making the temperature distribution of the test workpiece in the detection scene more obvious and clear, which helps to enhance the detection sensitivity of the infrared thermal imaging system and improve the quality and interpretability of the image.

[0017] Furthermore, the bottom of the tested piece is placed on a fixed base, which ensures the stability of the tested piece during the testing process and the accuracy of the test results.

[0018] Furthermore, the computer equipment can receive data from the infrared imager and controller in real time, and perform rapid processing and analysis, thus achieving centralized control and automated management of the entire detection process.

[0019] Furthermore, as a core component in the computer device, the control module can efficiently process the signals from the infrared imager. Through the precise capture and conversion of the signal acquisition module, the images and data acquired by the infrared imager can be quickly received and processed by the control module, providing a basis for subsequent analysis and decision-making.

[0020] The present invention also provides a method for detecting the penetration depth of tin of via solder joints based on infrared thermal imaging. The infrared thermal imaging technology is used, and there is no need for direct contact with the tested piece, thereby avoiding damage or contamination of the tested piece that may be caused by physical contact. This ensures the integrity and reusability of the tested piece, and is particularly suitable for testing scenarios with high quality requirements such as precision electronic components. Infrared thermal imaging technology has high sensitivity and can accurately capture slight temperature changes on the surface of the tested piece. Combined with the data processing and analysis of infrared images by the control system, the penetration depth of tin of the via solder joints can be accurately measured, providing a reliable basis for quality assessment. The excitation source unit quickly forms a thermal environment around the tested piece, and the infrared thermal imaging camera immediately takes pictures. The control system quickly processes the captured infrared images, thereby completing the detection task in a short time and improving the detection efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of the structure of a via solder joint tin penetration depth detection device based on infrared thermal imaging in an embodiment of the present invention; Figure 2 A schematic diagram of the control principle of a computer device in an embodiment of the present invention; Figure 3 This is a flow chart of a method for detecting tin penetration depth of via-hole solder joints based on infrared thermal imaging in an embodiment of the present invention; Figure 4 is an optical microscopic image of the sample under test in the embodiment of the present invention, wherein Figure 4 a is the schematic diagram of the welding front of the sample under test. Figure 4 b is a schematic diagram of the welding back side of the sample under test; Figure 5 This is a comparison diagram of temperature change images before and after data processing in an embodiment of the present invention, where Figure 5 a is a schematic diagram before denoising; Figure 5 b is the schematic diagram after denoising; Figure 6 It is an infrared thermal imaging image calculated by different data compression methods in the embodiment of the present invention; wherein, Figure 6 a is a schematic diagram of polynomial coefficients; Figure 6 b is a schematic diagram of the average temperature difference; Figure 7 The comparison between the method of the present invention and the three-dimensional reconstruction result of rays in the embodiment of the present invention; wherein, Figure 7 a is a schematic diagram of the method of the present invention; Figure 7 b is a schematic diagram of ray three-dimensional reconstruction; Figure 8 Schematic diagram of point cloud reconstruction image of solder joints with different tin penetration depths in an embodiment of the present invention; Fig. 9 A schematic diagram of a first internal structure of a computer device in an embodiment of the present invention; Fig.10 A schematic diagram of a second structure inside a computer device according to an embodiment of the present invention; In the figure: 1. excitation source unit; 2. controller; 3. computer equipment; 4. infrared thermal imager; 5. test piece; 6. fixed base; 7. external equipment; 31. signal acquisition module; 32. control module; 33. signal output module; 34. processor; 35. memory; 36. computer program; 37. bus; 38. display unit; 39. I / O interface; 310. network adapter; 351. RAM unit; 352. cache storage unit; 353. ROM unit; 354. program / utility; 355. program module. DETAILED DESCRIPTION

[0022] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0023] The purpose of the present invention is to provide a device and method for detecting the penetration depth of tin in a via-hole solder joint based on infrared thermal imaging, so as to solve the technical problem of how to quantitatively detect the penetration depth of tin in the prior art.

[0024] The present invention is further described in detail below in conjunction with the accompanying drawings: Example 1 See also Figure 1 In one embodiment of the present invention, a device for detecting tin penetration depth of via-hole solder joints based on infrared thermal imaging is provided, comprising an excitation source unit 1, a control system, an infrared imager 4 and a test piece 5; a plurality of via-hole solder joints are distributed on the surface of the test piece 5, the infrared imager 4 and the excitation source unit 1 are respectively located on both sides of the test piece 5, and the excitation source unit 1 is used to heat the surface of the test piece 5; a camera of the infrared imager 4 is set to aim at a plurality of via-hole solder joints on the surface of the test piece 5; and a control end of the control system is respectively connected to a control end of the infrared imager 4 and a control end of the excitation source unit 1.

[0025] Specifically, the plate surface of the test piece 5 is arranged in parallel with the heating surface of the excitation source unit 1 .

[0026] Specifically, there are intervals between the tested object 5 and the infrared imager 4 and the excitation source unit 1 .

[0027] Specifically, the bottom of the tested piece 5 is placed on the fixed base 6 .

[0028] In this embodiment, the excitation source unit 1, the infrared imager 4 and the tested object 5 constitute the core part of the detection device. There are several through-hole solder joints distributed on the surface of the tested object 5, and these solder joints are the target areas for detection. The infrared imager 4 and the excitation source unit 1 are respectively located on both sides of the tested object 5. Such a layout ensures that the infrared imager 4 can clearly capture the infrared image of the solder joints on the surface of the tested object 5, and the excitation source unit 1 can evenly heat the surface of the tested object 5. The board surface of the tested object 5 is arranged parallel to the heating surface of the excitation source unit 1, which helps to achieve a uniform heating effect and improve the accuracy of the detection. An appropriate spacing is set between the tested object 5 and the infrared imager 4 and the excitation source unit 1 to ensure the smooth progress of the detection process and avoid potential interference factors. The bottom of the tested object 5 is placed on the fixed base 6, which provides a stable support to ensure the stability of the tested object 5 during the detection process.

[0029] Specifically, the control system includes a controller 2 and a computer device 3; The driving end of the controller 2 is connected to the excitation source unit 1 , and the control end of the controller 2 and the control end of the infrared imager 4 are connected to the computer device 3 respectively.

[0030] Specifically, according to Figure 2 As shown, a control module 32 is provided in the computer device 3, the input end of the control module 32 is connected to the signal acquisition module 31, and the input end of the signal acquisition module 31 is connected to the infrared imager 4; the output end of the control module 32 is connected to the signal output module 33, and the output end of the signal output module 33 is respectively connected to the processor 34 and the controller 2; the driving end of the controller 2 is connected to the excitation source unit 1.

[0031] In this embodiment, the controller 2 is responsible for receiving instructions from the computer device 3 and controlling the heating operation of the excitation source unit 1. The signal acquisition module 31 receives the captured infrared image signal from the infrared imager 4 and transmits it to the control module 32 after preliminary processing.

[0032] The control module 32 receives the infrared image signal transmitted by the signal acquisition module 31, and performs data processing and analysis according to a preset algorithm or model.

[0033] The signal output module 33 converts the processing result of the control module 32 into a control signal, and sends it to the processor 34 (for further analysis or data storage) and the controller 2 (for adjusting the heating state of the excitation source unit 1).

[0034] The control loop in this embodiment is as follows: The controller 2 adjusts the heating power and time of the excitation source unit 1 according to the instruction of the computer device 3 to form a heating environment for the test piece 5 .

[0035] The infrared imager 4 captures the infrared image of the surface of the heated test piece 5 and transmits it to the computer device 3 for processing.

[0036] The computer device 3 adjusts the heating state of the excitation source unit 1 in real time through the controller 2 according to the processing result until the best detection effect is achieved.

[0037] In this embodiment, the excitation source unit 1 introduces or generates heat in infrared thermal imaging, so that the temperature distribution of the workpiece 5 under test in the detection scene is more obvious and clear. This helps to enhance the detection sensitivity of the infrared thermal imaging system and improve the quality and interpretability of the image. The controller 2 uses the computer device 3 as the host computer and adjusts the output power of the excitation source according to the instructions issued by the computer device 3. The fixed base 6 is used to clamp the workpiece under test and keep the workpiece state relatively stable during the detection process. The infrared imager 4 collects the thermal radiation on the surface of the workpiece, converts it into a thermal map and outputs it to the computer. Finally, the computer device 3 processes and analyzes the data collected by the infrared imager 4, and provides accurate results on the tin penetration depth of the via solder joint. This device combines the synergistic effect of the excitation source unit 1, the infrared thermal imager 4 and the computer device 3, so that it has the technical advantages of high efficiency, accuracy, safety and controllability in the field of tin penetration depth detection.

[0038] In summary, this embodiment provides a via solder joint tin penetration depth detection device based on infrared thermal imaging, wherein the infrared imager and the excitation source unit are respectively located on both sides of the test piece, and the excitation source unit is used to heat the surface of the test piece; the camera of the infrared imager is aimed at a plurality of via solder joints on the surface of the test piece; the surface of the test piece can be quickly heated by the excitation source unit, and the infrared imager can capture and record the temperature change in real time, and feed the captured image back to the control system, and the tin penetration depth of the via solder joint is obtained through processing by the control system, thereby effectively improving the tin penetration depth detection efficiency of the via solder joint.

[0039] Example 2 according to Figure 3 As shown, this embodiment 2 provides a method for detecting the penetration depth of tin of a via-hole solder joint based on infrared thermal imaging, based on the above-mentioned device for detecting the penetration depth of tin of a via-hole solder joint based on infrared thermal imaging, including the following process: Step 1, the control system drives the power of the excitation source unit 1 to heat the area around the test piece 5 to form a thermal environment; Step 2, the camera of the infrared thermal imaging 4 is aimed at the test piece 5 to take a picture, and the taken infrared image is transmitted to the control system; Step 3: The control system processes and analyzes the captured infrared image to obtain the tin penetration depth of the via solder joint.

[0040] Specifically, the excitation source unit 1 actively heats the test piece 5, and controls its output power through the controller 2, thereby improving the information content and availability of the collected image. The infrared thermal imager 4 is used to collect infrared images of the workpiece surface during the temperature change process. Compared with a single infrared image, this multi-frame dynamic information contains different material physical properties under time series conditions. Taking it as an analysis object, more relevant information can be obtained and the detection accuracy can be improved. In the computer device 3, the infrared image sequence is first denoised, and then the infrared image sequence is compressed to reduce the detection error, improve the signal-to-noise ratio of the image, and strengthen the correlation between the infrared image and the tin penetration depth. Finally, the tin penetration surface morphology of the workpiece under test is reconstructed according to the compressed image and the tin penetration height is calculated.

[0041] according to Figure 4 As shown, Figure 4 a is the schematic diagram of the welding front of the sample under test. Figure 4 b is a schematic diagram of the welded back side of the sample under test; the data processing method used in this embodiment is: firstly, the time-temperature curve of each pixel point in the time-series infrared image is extracted, and the curve segment of interest is intercepted, and the image time-frequency analysis method or function fitting method is used to filter the high-frequency noise in the image, such as Figure 5 middle Figure 5 a and Figure 5 b. Secondly, the time series infrared image is compressed, as shown in Figure 6 middle Figure 6 a and Figure 6 As shown in b, the compressed infrared image can effectively reflect the penetration depth of the via solder joints. Figure 7 middle Figure 7 a and Figure 7 As shown in b.

[0042] The specific process is as follows: Assume that the infrared thermal imager captures N frames of images, where the length and width of each frame are L and W respectively, then the denoised and sorted time-series infrared image can be represented as a three-dimensional matrix of size L×W×N. Further, suppose n∈[1,N] is the time-series index of a single frame image, x∈[1,L] is the column index of a single frame image, and y∈[1,W] is the row index of a single frame image, then the nth frame image can be represented as P(x,y,n).

[0043] Specifically, a compression method is provided for calculating the tin penetration depth of a via solder joint according to the compression result, including the following process: The signal difference captured by two frames of images at a unit time interval is taken as the calculation object, and the thermal radiation gradient per unit time is obtained through mapping based on the signal difference. Then, the time series window is slid to calculate the time series thermal radiation gradient of multiple frames of images in a continuous unit time. Finally, the time series thermal radiation gradient is weighted and averaged to obtain the thermal imaging image of the workpiece under test characterized by the temperature change rate.

[0044] The specific process is as follows: S1, calculate the thermal radiation gradient of the workpiece under test per unit time interval. t Two frames of images at intervals and , then the signal difference can be expressed as:

[0045] S2, corresponding to unit time t The thermal radiation gradient under the interval can be expressed as

[0046] In the above formula It represents the specific mapping calculation method used, which includes but is not limited to the commonly used linear, nonlinear mapping and partial derivative calculation methods.

[0047] S3, sliding time series window, the weighted average of the time series thermal radiation gradient in continuous unit time can be expressed as:

[0048] In the formula, is the weight coefficient of each thermal radiation gradient, which is positively correlated with Formula 2.

[0049] Specifically, a compression method is provided for calculating the tin penetration depth of a via solder joint according to the compression result, including the following process: Based on the premise that the physical properties of the material of the workpiece under test change with temperature within a certain temperature dynamic range, polynomial fitting is performed according to the temperature change curve of fixed pixel points in multi-frame time-series infrared images, and the thermal imaging image of the workpiece under test characterized by the temperature change rate is constructed using the fitting coefficients.

[0050] The specific process is as follows: L1, for the multi-frame sequential infrared images of the workpiece under test acquired within a certain period of time, select a specific pixel point in the image and record its temperature value at different time points. Thus, the sequential temperature of the pixel point is formed. In the frame image The time series temperature of a pixel can be expressed as .

[0051] L2, polynomial fitting is performed on the time series temperature, and the polynomial function is used to approximate or fit the temperature change trend over time. Among them, the polynomial fitting method includes but is not limited to the least squares method, and the number of polynomial fitting can be adjusted according to actual needs. Here, a cubic polynomial is used as an example to capture possible nonlinear relationships. The function obtained by fitting describes the change of the temperature of a specific pixel point of the measured workpiece over time, which can be expressed as:

[0052] In the formula, All are fitting coefficients.

[0053] L3, based on the dynamic characteristics reflected by the temperature change rate, by calculating the derivative of the polynomial, a thermal image based on the temperature change rate is constructed, that is:

[0054] After calculation using the above formula, the thermal image can more intuitively display the temperature change trend of the workpiece under test over time, which helps to more comprehensively understand and analyze its thermal properties.

[0055] Through the method for detecting the penetration depth of via-hole solder joints based on infrared thermal imaging provided in this embodiment, point cloud reconstructed images of solder joints with different penetration depths can be calculated by computer equipment, such as Figure 8 shown.

[0056] according to Fig. 9 As shown, in this embodiment, the control system includes a controller 2 and a computer device 3, wherein the computer device 3 also includes: a memory 35 and a computer program 36 stored in the memory 35 and executable on a processor 34, and when the computer program 36 is executed by the processor 34, the method for detecting the penetration depth of a via-hole solder joint based on infrared thermal imaging in the embodiment is implemented. Alternatively, when the computer program 36 is executed by the processor 34, the functions of each model / unit in the system for detecting the penetration depth of a via-hole solder joint based on infrared thermal imaging in the embodiment are implemented.

[0057] The computer device 3 may be a computing device such as a desktop computer, a notebook, a PDA, or a cloud server. The computer device 3 may include, but is not limited to, a processor 34 and a memory 35. Those skilled in the art will appreciate that Figure 3 It is only an example of computer device 3 and does not constitute a limitation of computer device 3. It may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, the computer device may also include input and output devices, network access devices, buses, etc.

[0058] The processor 34 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor, etc.

[0059] The memory 35 may be an internal storage unit of the computer device 3, such as a hard disk or memory of the computer device 3. The memory 35 may also be an external storage device of the computer device 3, such as a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (FlashCard), etc. equipped on the computer device 3.

[0060] The memory 35 may also include both an internal storage unit of the computer device 3 and an external storage device. The memory 35 is used to store computer programs and other programs and data required by the computer device. The memory 35 may also be used to temporarily store data that has been output or is to be output.

[0061] according to Fig.10 As shown, the components of the computer device 3 may include but are not limited to: at least one processor 34, at least one memory 35, a bus 37 connecting different platform components, a display unit 38, etc.

[0062] The memory 35 stores program codes, which can be executed by the processor 34, so that the processor 34 executes the steps according to various exemplary embodiments of the present invention described in the above method section of this specification. For example, the processor 34 can execute the following steps: Figure 3 Follow the steps shown in .

[0063] The memory 35 may include a readable medium in the form of a volatile storage unit, such as a RAM unit 351 and / or a cache storage unit 352 , and may further include a ROM unit 353 .

[0064] The memory 35 may also include a program / utility 354 having a set (at least one) of program modules 355, such program modules 355 including but not limited to: an operating system, one or more application programs, other program modules, and program data, each of which or some combination may include an implementation of a network environment.

[0065] Bus 37 may represent one or more of several types of bus structures, including a memory unit bus or memory unit controller, a peripheral bus, an accelerated graphics port, a processing unit, or a local bus using any of a variety of bus architectures.

[0066] The computer device 3 may also communicate with one or more external devices 7 (e.g., keyboards, pointing devices, Bluetooth devices, etc.), may communicate with one or more devices that enable a user to interact with the computer device 3, and / or may communicate with any device that enables the computer device 3 to communicate with one or more other computing devices (e.g., routers, modems, etc.). Such communication may be performed via an I / O interface 39. Furthermore, the computer device 3 may also communicate with one or more networks (e.g., local area networks (LANs), wide area networks (WANs), and / or public networks, such as the Internet) via a network adapter 310. The network adapter 310 may communicate with other modules of the computer device 3 via a bus 37. It should be understood that, although not shown in the figure, other hardware and / or software modules may be used in conjunction with the computer device 3, including but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage platforms, etc.

[0067] In this embodiment, the infrared thermal imager 4 can be equipped with a high-power magnification lens to achieve high-resolution detection of the penetration depth of tin in the via-hole solder joints of the printed circuit board, and the detection of tiny-sized solder joints is more accurate. The detection cycle of the method provided by this embodiment is relatively short, which provides convenient conditions for large-scale detection of printed circuit boards. For the same test piece, the currently commonly used X-ray detection method takes more than half an hour to complete the detection, while the method proposed in the present invention only takes a dozen seconds. This embodiment can capture slight changes in the penetration depth of tin in the solder joints on the printed circuit board, and respond sensitively within the dynamic temperature range.

[0068] The present invention is applicable to a variety of manufacturing processes for printed circuit boards, can flexibly adapt to circuit boards of different specifications and requirements, and provides an efficient and reliable tin penetration depth detection solution for the electronics manufacturing industry.

[0069] The present invention adopts infrared thermal imaging technology to perform tin penetration depth detection, without physical contact with the object to be detected, thus avoiding the damage caused by traditional detection methods and helping to maintain the integrity and stability of the object to be detected.

[0070] The excitation source used in the present invention will not cause radiation damage to the human body, and the power of the excitation source is controllable, and will not cause harm to the detection object, environment and personnel during the implementation process.

[0071] The infrared thermal imaging nondestructive testing technology in the present invention is a technology that uses the principle of infrared thermal radiation to capture the thermal distribution image of the target object through an infrared thermal imager to achieve rapid, non-contact detection of surface and internal defects of the object. The use of infrared thermal imaging technology can improve detection efficiency and reduce detection costs. It is currently widely used in the detection of coating thickness, fatigue cracks, etc.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A device for detecting the penetration depth of via solder joints based on infrared thermal imaging, characterized in that: It comprises an excitation source unit (1), a control system, an infrared imager (4), and a test piece (5); A plurality of via-hole solder joints are distributed on the surface of the test object (5); the infrared imager (4) and the excitation source unit (1) are respectively located on two sides of the test object (5); the excitation source unit (1) is used to heat the surface of the test object (5); the camera of the infrared imager (4) is aimed at the plurality of via-hole solder joints on the surface of the test object (5); The control end of the control system is respectively connected to the control end of the infrared imager (4) and the control end of the excitation source unit (1).

2. The device for detecting the penetration depth of via-hole solder joints based on infrared thermal imaging according to claim 1, characterized in that: The plate surface of the tested object (5) is arranged parallel to the heating surface of the excitation source unit (1).

3. The device for detecting the penetration depth of via-hole solder joints based on infrared thermal imaging according to claim 1, characterized in that: A distance is provided between the tested object (5) and the infrared imager (4) and the excitation source unit (1).

4. The device for detecting tin penetration depth of via-hole solder joints based on infrared thermal imaging according to claim 1, characterized in that: The bottom of the tested object (5) is placed on a fixed base (6).

5. The device for detecting tin penetration depth of via-hole solder joints based on infrared thermal imaging according to claim 1, characterized in that: The control system comprises a controller (2) and a computer device (3); The driving end of the controller (2) is connected to the excitation source unit (1), and the control end of the controller (2) and the control end of the infrared imager (4) are respectively connected to the computer device (3).

6. The device for detecting tin penetration depth of via-hole solder joints based on infrared thermal imaging according to claim 5, characterized in that: The computer device (3) is provided with a control module (32), the input end of the control module (32) is connected to the signal acquisition module (31), and the input end of the signal acquisition module (31) is connected to the infrared imager (4); the output end of the control module (32) is connected to the signal output module (33), and the output end of the signal output module (33) is respectively connected to the processor (34) and the controller (2); the driving end of the controller (2) is connected to the excitation source unit (1).

7. A method for detecting the penetration depth of via solder joints based on infrared thermal imaging, characterized in that: A via solder joint tin penetration depth detection device based on infrared thermal imaging according to any one of claims 1 to 6, comprising the following process: The control system drives the power of the excitation source unit (1) to heat the area around the tested object (5) to form a thermal environment; The infrared thermal imaging camera (4) is aimed at the test piece (5) to take a picture, and transmits the taken infrared image to the control system; The control system processes and analyzes the captured infrared images to obtain the tin penetration depth of the via-hole solder joints.

8. The method for detecting the penetration depth of via-hole solder joints based on infrared thermal imaging according to claim 7, characterized in that: The control system performs data processing on the captured infrared images, and during the analysis, the control system performs denoising on the infrared image sequence, and performs data compression on the infrared image sequence, and calculates the tin penetration depth of the through-hole solder joint according to the compression result.

9. The method for detecting the penetration depth of via-hole solder joints based on infrared thermal imaging according to claim 8, characterized in that: The specific process of calculating the tin penetration depth of the via solder joint according to the compression result is as follows: The signal difference captured by two frames of images at a unit time interval is taken as the calculation object, and the thermal radiation gradient per unit time is obtained through mapping based on the signal difference. Then, the time series window is slid to calculate the time series thermal radiation gradient of multiple frames of images in a continuous unit time. Finally, the time series thermal radiation gradient is weighted and averaged to obtain the thermal imaging image of the workpiece under test characterized by the temperature change rate.

10. The method for detecting tin penetration depth of via-hole solder joints based on infrared thermal imaging according to claim 8, characterized in that: The specific process of calculating the tin penetration depth of the via solder joint according to the compression result is as follows: Based on the premise that the physical properties of the material of the workpiece (5) under test change with temperature within a temperature dynamic range, a polynomial fitting is performed according to the temperature change curve of fixed pixel points in a multi-frame time-series infrared image, and a thermal imaging image of the workpiece under test characterized by the temperature change rate is constructed using the fitting coefficients.

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