CA2363171A1 - Short-circuit locator for printed circuit boards using a visible-nir camera - Google Patents
Short-circuit locator for printed circuit boards using a visible-nir camera Download PDFInfo
- Publication number
- CA2363171A1 CA2363171A1 CA 2363171 CA2363171A CA2363171A1 CA 2363171 A1 CA2363171 A1 CA 2363171A1 CA 2363171 CA2363171 CA 2363171 CA 2363171 A CA2363171 A CA 2363171A CA 2363171 A1 CA2363171 A1 CA 2363171A1
- Authority
- CA
- Canada
- Prior art keywords
- visible
- short
- nir
- image
- computer device
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/28—Testing of electronic circuits, e.g. by signal tracer
- G01R31/302—Contactless testing
- G01R31/308—Contactless testing using non-ionising electromagnetic radiation, e.g. optical radiation
- G01R31/309—Contactless testing using non-ionising electromagnetic radiation, e.g. optical radiation of printed or hybrid circuits or circuit substrates
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/28—Testing of electronic circuits, e.g. by signal tracer
- G01R31/2801—Testing of printed circuits, backplanes, motherboards, hybrid circuits or carriers for multichip packages [MCP]
- G01R31/281—Specific types of tests or tests for a specific type of fault, e.g. thermal mapping, shorts testing
- G01R31/2812—Checking for open circuits or shorts, e.g. solder bridges; Testing conductivity, resistivity or impedance
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- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Health & Medical Sciences (AREA)
- Computer Vision & Pattern Recognition (AREA)
- Electromagnetism (AREA)
- Toxicology (AREA)
- General Engineering & Computer Science (AREA)
- General Physics & Mathematics (AREA)
- Investigating Or Analyzing Materials Using Thermal Means (AREA)
Abstract
A Printed Circuit Board (PCB), bare or populated with electronic components, may present some short-circuits occurring during the manufacturing or the assembly process. By taking different images of the entire PCB with a Visible-NIR camera at specific times, before and after the short-circuit current is applied, and by processing them, it is possible to find the exact location of the short-circuit fault on the PCB. The Visible-NIR Focal Plan Array (FPA) of the camera, which is sensitive in the NIR band, is able to sense and to detect an extra signal due to the heat radiation of the short-circuit area. Once this extra signal has been detected for some identified pixels, these pixels are reported to the Visible image to pin point the exact location of the short-circuit fault. The fault can be corrected by the usual repair methods.
Description
BACKGROUND OF THE INVENTION.
The present invention relates to inspection or test apparatus for electronic Printed Circuit Board (PCB), and more particularly to detection and location of specific defects occurring during the manufacturing of the bare PCB itself or during the assembly process of the populated PCB
(populated PCB means bare PCB with the electronic components installed and already soldered on it).
On a Printed Circuit Board, where all the electronic components (Integrated Circuits, resistors, capacitors, connectors,...) are already installed and soldered, it is easy to know if there is some short-circuit, between the power supplies conductors or between two signal conductors, but it is impossible to locate it in order to remove this fault to get again a functional PCB. Simple devices or apparatus exist already to detect the presence of a short-circuit but none of them is able to pin point precisely their location on a Printed Circuit Board (bare or populated).
This invention is based on the thermal properties of a typical short-circuit.
The short-circuit thermal signature will show the exact and precise location of an hardware short-circuit (due to excess of solder, solder bridge, manufacturing or assembly process weakness,...) on the PCB and, as a consequence, the opportunity to repair the PCB by removing the short-circuit fault. This invention is based on the fact that a short-circuit has a certain resistance value, greater than the PCB
conductor traces carrying the normal current. As a consequence, this small resistance dissipates more heat that the normal path carrying the current through the PCB traces.
The short-circuit creates a local temperature elevation which is detectable by a sensitive Charge Coupled Device (CCD) photon detector array, used in a Visible-NIR (Near Infrared) camera.
SUMMARY OF THE INVENTION.
The present invention is directed to electro-optic image capturing system for obtaining images of a bare or populated PCB. The system includes a support plate to install the PCB under test and a single wall complete protective enclosure having the internal side covered with an absorbing (high emissivity) paint or coating. This enclosure has to absorb all the internal Infrared radiation and to isolate the imaging system from the environment light noise and variation. The associate image capturing system consists of a visible-NIR (Near Infrared) CCD
camera with associated optics. The CCD camera detects any change in light intensity which gives information about the level of detected light.
Reference to FIG. 1A, the spectral response of the Focal Plan Array (FPA) of this type of Visible-NIR CCD technology shows a detectable and measurable response in the Near Infrared (NIR) band (above 800 nanometers). This sensitivity in this NIR band is good enough to generate a signal higher when a Printed Circuit Board area is warmer or hotter due to the presence of high current through the short-circuit. This short -circuit defect has a small resistance value which generates enough detectable heat in the NIR band when the current is passing through it. The sensitivity is high for this type of CCD camera which are based photon detector technology.
Reference to FIG. 1B, the overlap of the spectral response of the FPA and the IR emission in the NIR band permits the detection of small amount of heat due to the Joule's effect of the short-circuit presenting a non-zero resistance value.
All the captured image are stored and processed in the Computer Device.
First an image is captured before applying the short-circuit current in order to get a Reference image. Next, just before the short-current time duration is finished, a second image called Heat image is captured, containing information of the warmer pixels due the high sensitivity of this CCD photon detector in the NIR band due to their high quantum efficiency.
Reference to FIG. 2A , a typical histogram (distribution of pixel amplitude of the entire PCB) of a PCB image captured at room temperature before the short-circuit current is applied. This image is called the Reference image.
The present invention relates to inspection or test apparatus for electronic Printed Circuit Board (PCB), and more particularly to detection and location of specific defects occurring during the manufacturing of the bare PCB itself or during the assembly process of the populated PCB
(populated PCB means bare PCB with the electronic components installed and already soldered on it).
On a Printed Circuit Board, where all the electronic components (Integrated Circuits, resistors, capacitors, connectors,...) are already installed and soldered, it is easy to know if there is some short-circuit, between the power supplies conductors or between two signal conductors, but it is impossible to locate it in order to remove this fault to get again a functional PCB. Simple devices or apparatus exist already to detect the presence of a short-circuit but none of them is able to pin point precisely their location on a Printed Circuit Board (bare or populated).
This invention is based on the thermal properties of a typical short-circuit.
The short-circuit thermal signature will show the exact and precise location of an hardware short-circuit (due to excess of solder, solder bridge, manufacturing or assembly process weakness,...) on the PCB and, as a consequence, the opportunity to repair the PCB by removing the short-circuit fault. This invention is based on the fact that a short-circuit has a certain resistance value, greater than the PCB
conductor traces carrying the normal current. As a consequence, this small resistance dissipates more heat that the normal path carrying the current through the PCB traces.
The short-circuit creates a local temperature elevation which is detectable by a sensitive Charge Coupled Device (CCD) photon detector array, used in a Visible-NIR (Near Infrared) camera.
SUMMARY OF THE INVENTION.
The present invention is directed to electro-optic image capturing system for obtaining images of a bare or populated PCB. The system includes a support plate to install the PCB under test and a single wall complete protective enclosure having the internal side covered with an absorbing (high emissivity) paint or coating. This enclosure has to absorb all the internal Infrared radiation and to isolate the imaging system from the environment light noise and variation. The associate image capturing system consists of a visible-NIR (Near Infrared) CCD
camera with associated optics. The CCD camera detects any change in light intensity which gives information about the level of detected light.
Reference to FIG. 1A, the spectral response of the Focal Plan Array (FPA) of this type of Visible-NIR CCD technology shows a detectable and measurable response in the Near Infrared (NIR) band (above 800 nanometers). This sensitivity in this NIR band is good enough to generate a signal higher when a Printed Circuit Board area is warmer or hotter due to the presence of high current through the short-circuit. This short -circuit defect has a small resistance value which generates enough detectable heat in the NIR band when the current is passing through it. The sensitivity is high for this type of CCD camera which are based photon detector technology.
Reference to FIG. 1B, the overlap of the spectral response of the FPA and the IR emission in the NIR band permits the detection of small amount of heat due to the Joule's effect of the short-circuit presenting a non-zero resistance value.
All the captured image are stored and processed in the Computer Device.
First an image is captured before applying the short-circuit current in order to get a Reference image. Next, just before the short-current time duration is finished, a second image called Heat image is captured, containing information of the warmer pixels due the high sensitivity of this CCD photon detector in the NIR band due to their high quantum efficiency.
Reference to FIG. 2A , a typical histogram (distribution of pixel amplitude of the entire PCB) of a PCB image captured at room temperature before the short-circuit current is applied. This image is called the Reference image.
Reference to FIG. 2B, the histogram of the same previous PCB but the image has been captured just before the pulse current is gone. This image is called the Heat image. The warm area of the short-circuit location will emit some radiation in the NIR band, which are detectable by the Visible-NIR CCD. Some pixels will have a higher value ( black colored).
Reference to FIG. 2C, the histogram of the resulting image made by subtracting the Reference image from the Heat image and keeping the non-zero pixel value which the pixels of interest. The zero-pixels value are not shown because they are not carrying any heat information.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. IA is a curve showing a typical spectral sensitivity of a visible-NIR FPA
detector to notice the response of the photon detector in the NIR band;
FIG. 1B combines the detector sensitivity curve and the short-circuit IR heat radiation curve, to show the overlap between the two curves in the NIR band;
FIG. 2A is an example of an histogram for a Visible-NIR Reference image, before applying the short circuit current;
FIG. 2B is the histogram for the Visible-NIR Heat image, just before the short-circuit current pulse is gone, showing some pixels with higher values;
FIG. 2C is the histogram for the Visible-NIR Difference image, which is the difference between the Visible-NIR Heat image and the Visible-NIR Reference image, described in FIG. 2B
and FIG. 2A respectively, showing the pixels which are detected as warmer, due to the short-circuit radiation in the NIR band. The zero-value pixels are not represented;
FIG. 3 is a bloc diagram of the apparatus showing the hardware components of the system;
FIG. 4 shows details for the limiting current resistors and the connecting relays.
S
DESCRIPTION OF THE INVENTION.
Reference is now made to FIG. 3 of the drawing wherein a Printed Circuit Board 2 (PCB) to be tested is located on the base plate support 1, inside a protective light enclosure 3 to minimize the environmental light variation and external temperature perturbations.
As a initial set-up, connect the DC or AC power supply 17 leads at the appropriate location to the PCB, (normally a connector 19 with one or more contacts). Then set, on the Computer Device 9, the power supply pulse duration programmable from 50 milliseconds up to 2,000 milliseconds (increment of 50 milliseconds). This pulse duration is the time the connecting relays 16 will be closed to enable the current to flow through the PCB.
To protect the PCB 2 and to avoid the Power supply 17 to drop its own voltage or to be damaged, it is necessary to put a limiting resistor Rp in serie to limit the short-circuit current flowing through the PCB by using the simple formula:
Vs Imax - ---------Rp If the operator wants to limit the short-circuit current to Imax (in Amperes), and if the Power supply voltage is Vs (in volts), the limiting resistor value (in Ohms) will be:
Vs Rp - ------ ( Rp in Ohms ) Imax The resistor can be connected or installed in the resistors box 15 FIG. 4 show a typical implementation of such resistors.
The short-circuit test operation can start now.
As a first step, the Computer Device 9 will send an electrical pulse signal through the Digital Output Port Card 11 to enable the lamp driver 5 to illuminate the PCB with the lamp 4 on. During the time the lamp 4 illuminates the PCB, the Computer Device 9 will capture a video Visible image by using the Frame Grabber card 10 and store this image in the Computer Device memory. The Frame Grabber converts the Video signal 8, coming from the camera 7 and associated optics 6, in a digital bit map image. This Visible image will be used later on to show physically where is the location of the short-circuit..
As a second step, after the lamp 4 is off, the Computer Device 9 will capture a Reference image by using the Frame Grabber card 10 and store this image in the Computer Device memory.
As a third step, the Computer Device 9, through the Digital Output card 11, will send a Command signal 14 to activate the Connecting relays 16. By closing the contacts of the relays, the current coming from the Power Supply 17 will pass through the Limiting current resistors 15 and feed the PCB through the wires 18 and the connector 19. After the programmed time duration, the Connecting relays 16 are deactivated, current flowing through the PCB 2 is then stopped, and a Heat image is captured by the camera and store in Computer Device memory.
FIG. 4 show a typical implementation of such connecting relays 16.
Then, as a fourth step, the Computer Device 9 will compute the Difference image, which is the subtraction between the Heat image and the Reference image, on a pixel-by-pixel basis, to extract the pixels which are warmer than the Reference image. This difference between the NIR
Heat image and the Reference image will give the pixels which are warmer than the visible pixels, in the NIR wavelength bandwidth. These warmer pixels come from the heat activity generated by the current passing through the short-circuit path which gives a local heat increase. The sensitivity of the CCD Visible-NIR camera in the NIR wavelength bandwidth permits the detection of this extra small amount of Infrared radiation.
The monitor 12 will display the warm pixels by overlaying these pixels, in a different color, on the Visible image captured initially as a picture of the PCB. These identified warm pixels show the location of the electrical short-circuit fault.
An operator adjustable programmable threshold enables the operator to adjust the display of these identified warm pixels on the monitor 12. The Computer Device is operated by the operator with the keyboard and the mouse devices 13.
Reference to FIG. 2C, the histogram of the resulting image made by subtracting the Reference image from the Heat image and keeping the non-zero pixel value which the pixels of interest. The zero-pixels value are not shown because they are not carrying any heat information.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. IA is a curve showing a typical spectral sensitivity of a visible-NIR FPA
detector to notice the response of the photon detector in the NIR band;
FIG. 1B combines the detector sensitivity curve and the short-circuit IR heat radiation curve, to show the overlap between the two curves in the NIR band;
FIG. 2A is an example of an histogram for a Visible-NIR Reference image, before applying the short circuit current;
FIG. 2B is the histogram for the Visible-NIR Heat image, just before the short-circuit current pulse is gone, showing some pixels with higher values;
FIG. 2C is the histogram for the Visible-NIR Difference image, which is the difference between the Visible-NIR Heat image and the Visible-NIR Reference image, described in FIG. 2B
and FIG. 2A respectively, showing the pixels which are detected as warmer, due to the short-circuit radiation in the NIR band. The zero-value pixels are not represented;
FIG. 3 is a bloc diagram of the apparatus showing the hardware components of the system;
FIG. 4 shows details for the limiting current resistors and the connecting relays.
S
DESCRIPTION OF THE INVENTION.
Reference is now made to FIG. 3 of the drawing wherein a Printed Circuit Board 2 (PCB) to be tested is located on the base plate support 1, inside a protective light enclosure 3 to minimize the environmental light variation and external temperature perturbations.
As a initial set-up, connect the DC or AC power supply 17 leads at the appropriate location to the PCB, (normally a connector 19 with one or more contacts). Then set, on the Computer Device 9, the power supply pulse duration programmable from 50 milliseconds up to 2,000 milliseconds (increment of 50 milliseconds). This pulse duration is the time the connecting relays 16 will be closed to enable the current to flow through the PCB.
To protect the PCB 2 and to avoid the Power supply 17 to drop its own voltage or to be damaged, it is necessary to put a limiting resistor Rp in serie to limit the short-circuit current flowing through the PCB by using the simple formula:
Vs Imax - ---------Rp If the operator wants to limit the short-circuit current to Imax (in Amperes), and if the Power supply voltage is Vs (in volts), the limiting resistor value (in Ohms) will be:
Vs Rp - ------ ( Rp in Ohms ) Imax The resistor can be connected or installed in the resistors box 15 FIG. 4 show a typical implementation of such resistors.
The short-circuit test operation can start now.
As a first step, the Computer Device 9 will send an electrical pulse signal through the Digital Output Port Card 11 to enable the lamp driver 5 to illuminate the PCB with the lamp 4 on. During the time the lamp 4 illuminates the PCB, the Computer Device 9 will capture a video Visible image by using the Frame Grabber card 10 and store this image in the Computer Device memory. The Frame Grabber converts the Video signal 8, coming from the camera 7 and associated optics 6, in a digital bit map image. This Visible image will be used later on to show physically where is the location of the short-circuit..
As a second step, after the lamp 4 is off, the Computer Device 9 will capture a Reference image by using the Frame Grabber card 10 and store this image in the Computer Device memory.
As a third step, the Computer Device 9, through the Digital Output card 11, will send a Command signal 14 to activate the Connecting relays 16. By closing the contacts of the relays, the current coming from the Power Supply 17 will pass through the Limiting current resistors 15 and feed the PCB through the wires 18 and the connector 19. After the programmed time duration, the Connecting relays 16 are deactivated, current flowing through the PCB 2 is then stopped, and a Heat image is captured by the camera and store in Computer Device memory.
FIG. 4 show a typical implementation of such connecting relays 16.
Then, as a fourth step, the Computer Device 9 will compute the Difference image, which is the subtraction between the Heat image and the Reference image, on a pixel-by-pixel basis, to extract the pixels which are warmer than the Reference image. This difference between the NIR
Heat image and the Reference image will give the pixels which are warmer than the visible pixels, in the NIR wavelength bandwidth. These warmer pixels come from the heat activity generated by the current passing through the short-circuit path which gives a local heat increase. The sensitivity of the CCD Visible-NIR camera in the NIR wavelength bandwidth permits the detection of this extra small amount of Infrared radiation.
The monitor 12 will display the warm pixels by overlaying these pixels, in a different color, on the Visible image captured initially as a picture of the PCB. These identified warm pixels show the location of the electrical short-circuit fault.
An operator adjustable programmable threshold enables the operator to adjust the display of these identified warm pixels on the monitor 12. The Computer Device is operated by the operator with the keyboard and the mouse devices 13.
Claims (14)
1. An apparatus comprising:
-a Visible-NIR camera with its associate optics, -a protective surrounding enclosure to absorb visible-NIR radiation, -a lamp emitting visible light, -a set of connecting relays, -a set of limiting current resistors, -a computer device including a Frame Grabber and Digital Output cards and keyboard/mouse peripherals, -an application software to capture and to process digital images and to display the results on a monitor or on any peripheral and to activate digital output pulses to switch ON/OFF the connecting relays and the lamp driver.
-a Visible-NIR camera with its associate optics, -a protective surrounding enclosure to absorb visible-NIR radiation, -a lamp emitting visible light, -a set of connecting relays, -a set of limiting current resistors, -a computer device including a Frame Grabber and Digital Output cards and keyboard/mouse peripherals, -an application software to capture and to process digital images and to display the results on a monitor or on any peripheral and to activate digital output pulses to switch ON/OFF the connecting relays and the lamp driver.
2. A Visible-NIR camera, as defined in claim 1, in which the Focal Plan Array is sensitive to Visible light radiation from 400 to 800 nanometers and to NIR radiation from 800 nanometers and up.
3. A single wall protective enclosure, as defined in claim 1, with the internal side covered with an absorbing (high emissivity) paint or coating or made with an absorbing material in the visible-NIR band, to isolate the imaging system from the external visible-NIR
perturbation and variation.
perturbation and variation.
4. A lamp, as defined in claim 1, to illuminate the PCB under test during the initial Visible image capture.
5. A set of connecting relays, as defined in claim 1, to enable the current to flow through the PCB.
6. A set of selectable limiting current resistors, as defined in claim l, to limit the current flowing through the PCB under test.
7. A computer device, as defined in claim 1, to capture and to process frames from the Visible-NIR camera and to display the result image and to provide electrical signals to the connecting relays and to the lamp driver.
8. A computer device application software, as referenced to claim 7, to capture the frames coming from the camera at specific times in direct relation with the switching ON/OFF of the connecting relays, to average consecutive frames to get a better quality image, to transfer the frames into the computer device memory.
9. A computer device application software, as referenced to claim 7, to process the frames according to the software application rules or algorithms and, more precisely, to subtract the initial image (Reference image) from the short-circuit image (Heat image) to extract only the NIR
variations in the pixel value in order to get the Difference image.
variations in the pixel value in order to get the Difference image.
10. A computer device application software, as referenced to claim 9, to adjust the decision threshold for the pixels of the Difference image to identify the warm pixels with the largest NIR
increments in order to locate more precisely the warmer spots, directly related to the short-circuit fault.
increments in order to locate more precisely the warmer spots, directly related to the short-circuit fault.
11. A computer device application software, as referenced to claim 10, to display, as an overlay, the warm pixels on the Visible image to pin point physically the short-circuit spatial location to get the Result image.
12. A computer device application software, as referenced to claim 11, to store or print the Result image in order to give the short-circuit fault location to the repair technician.
13. A computer device application software, as referenced to claim 8, with a user programmable time duration feature for the short-circuit power supply pulse which has to be applied to the PCB under test.
14. A computer device application software, as referenced to claim 13, to give the command signals to switch ON/OFF the connecting relays, at a controlled starting time and for a programmable time duration.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2363171 CA2363171A1 (en) | 2001-11-20 | 2001-11-20 | Short-circuit locator for printed circuit boards using a visible-nir camera |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2363171 CA2363171A1 (en) | 2001-11-20 | 2001-11-20 | Short-circuit locator for printed circuit boards using a visible-nir camera |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2363171A1 true CA2363171A1 (en) | 2003-05-20 |
Family
ID=4170547
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2363171 Abandoned CA2363171A1 (en) | 2001-11-20 | 2001-11-20 | Short-circuit locator for printed circuit boards using a visible-nir camera |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2363171A1 (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2010090774A1 (en) * | 2009-02-07 | 2010-08-12 | Tau Science Corporation | High speed detection of shunt defects in photovoltaic and optoelectronic devices |
| CN102072909A (en) * | 2009-10-15 | 2011-05-25 | 卡姆特有限公司 | Systems and methods for near infra-red optical inspection |
| CN102967820A (en) * | 2012-11-13 | 2013-03-13 | 东莞宇龙通信科技有限公司 | Mobile terminal and self-detection method thereof |
| CN115859904A (en) * | 2023-02-16 | 2023-03-28 | 上海合见工业软件集团有限公司 | PCB laminated structure short circuit detection system for EDA software |
| CN116309603A (en) * | 2023-05-24 | 2023-06-23 | 山东双海电气设备安装有限公司 | Visual detection method and system for power equipment faults |
| US11715195B2 (en) | 2021-03-22 | 2023-08-01 | International Business Machines Corporation | Machine learning-based circuit board inspection |
-
2001
- 2001-11-20 CA CA 2363171 patent/CA2363171A1/en not_active Abandoned
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2010090774A1 (en) * | 2009-02-07 | 2010-08-12 | Tau Science Corporation | High speed detection of shunt defects in photovoltaic and optoelectronic devices |
| CN102072909A (en) * | 2009-10-15 | 2011-05-25 | 卡姆特有限公司 | Systems and methods for near infra-red optical inspection |
| CN102967820A (en) * | 2012-11-13 | 2013-03-13 | 东莞宇龙通信科技有限公司 | Mobile terminal and self-detection method thereof |
| US11715195B2 (en) | 2021-03-22 | 2023-08-01 | International Business Machines Corporation | Machine learning-based circuit board inspection |
| CN115859904A (en) * | 2023-02-16 | 2023-03-28 | 上海合见工业软件集团有限公司 | PCB laminated structure short circuit detection system for EDA software |
| CN115859904B (en) * | 2023-02-16 | 2023-04-28 | 上海合见工业软件集团有限公司 | PCB laminated structure short circuit detection system for EDA software |
| CN116309603A (en) * | 2023-05-24 | 2023-06-23 | 山东双海电气设备安装有限公司 | Visual detection method and system for power equipment faults |
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