Circuit backplane detection device and circuit backplane detection method

Abstract

A circuit backplane detection device and detection method are used to detect the pad group of the circuit backplane, the pad group includes a first pad and a second pad for bonding with an LED chip, the circuit backplane detection device includes an electromagnetic component and an imaging component, the electromagnetic component includes a magnetic induction box and multiple compasses fixed in the magnetic induction box, and the imaging component includes a camera for acquiring images of the compasses. The magnetic induction box is placed on the circuit backplane, and the multiple compasses are arranged in a one-to-one correspondence with the multiple pad groups. When a changing current is passed through the circuit backplane, the image shows that the direction of the compass changes, indicating that the pad group is normal; if the image shows that the direction of the compass remains unchanged, it means that the pad group is damaged. According to the change in the direction of the compass, it can be judged whether the corresponding pad is damaged, thereby realizing the detection of bad points on the circuit backplane before chip bonding, which is conducive to reducing the difficulty of repair and reducing production costs.

Description

Technical Field

[0001] The present invention relates to the technical field of displays, and in particular to a circuit backplane detection device and a detection method. Background Art

[0002] Micro-LED is a thin-film, miniaturized, arrayed LED (light-emitting diode) structure, with a size reduced to about 1 to 10 μm. After a large amount of transfer to the substrate, physical deposition is used to complete the protective layer and electrode, and then packaging is completed to complete the Micro-LED display. Micro-LED displays have good stability and long service life. At the same time, they also inherit the advantages of LED such as low power consumption, high color saturation, fast response speed, and strong contrast. They are widely used in wearable devices, ultra-large display screens, wireless optical communications and other fields.

[0003] During the production process of Micro-LED display panels, the LED chips need to be transferred from their respective growth substrates to the display panel. However, if any LED chip is damaged or has poor contact, a bad pixel will appear on the display panel after the transfer, affecting the imaging effect. The current structure of the Micro-LED display backplane drive circuit is only suitable for lighting up the LED chip after the massive transfer, and detecting the location of the bad pixel by detecting the outgoing light beam of the LED chip. However, sometimes, the cause of the bad pixel is not a problem with the LED chip, but damage to the display backplane, which causes the LED chip to fail to light up. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the purpose of the present application is to provide a circuit backplane detection device and a circuit backplane detection method, which can detect bad pixels on the display backplane before mass transfer, avoid chip bonding with bad pixels, reduce repair difficulty, and save production costs.

[0005] The present application provides a circuit backplane detection device for detecting a pad group of a circuit backplane, wherein the pad group includes a first pad and a second pad for bonding with an LED chip, and the circuit backplane detection device includes: an electromagnetic component, wherein the electromagnetic component includes a magnetic induction box and a plurality of compasses, wherein the plurality of compasses are fixed in the magnetic induction box;

[0006] An imaging component, the imaging component comprising a camera, the camera being disposed on one side of the magnetic sensing box, and the camera being used to acquire an image of the compass;

[0007] The magnetic induction box is placed on the circuit backplane so that each of the guiding needles corresponds to one of the pad groups.

[0008] By making the compass in the circuit backplane detection device correspond to the first pad and the second pad on the circuit backplane, and acquiring the image of the compass by the imaging component, when a changing current is passed through the first pad and the second pad, the changing electric field generates a magnetic field, causing the direction of the compass to change. If the image shows that the direction of the compass has changed, it means that the pad group is normal; if the image shows that the direction of the compass remains unchanged, it means that the pad group is damaged. According to the change in the direction of the compass, it can be determined whether the corresponding pad group is damaged, thereby realizing bad point detection on the circuit backplane before chip bonding, which is conducive to reducing the difficulty of repair and reducing production costs.

[0009] In one embodiment, the magnetic induction box includes a bottom plate and a plurality of first partitions, the plurality of first partitions are arranged at intervals on the bottom plate, the bottom plate and the plurality of first partitions are enclosed to form a plurality of first accommodating cavities, and the plurality of compasses are accommodated in the plurality of first accommodating cavities one by one. By arranging a plurality of first partitions arranged at intervals on the bottom plate to form a plurality of first accommodating cavities, the number of compasses is correspondingly multiple, thereby achieving the purpose of simultaneously detecting a plurality of pads on the circuit back plate, which is conducive to improving the detection efficiency.

[0010] In one embodiment, the material of the first partition is a magnetic isolation material, and the material of the bottom plate is an opaque material that can be penetrated by the magnetic field. By making the material of the first partition a magnetic isolation material, mutual interference of the electric fields in the two adjacent first accommodating cavities can be avoided, and by making the bottom plate a material that can be penetrated by the magnetic field, when the magnetic field on the circuit back plate changes, it can cause the compass to change its direction; by making the bottom plate an opaque material, when the imaging component obtains the image of the compass, interference caused by the pads or lines on the circuit back plate is avoided, and the problem of unclear imaging is avoided, which is conducive to improving the detection accuracy.

[0011] In one embodiment, the magnetic induction box further includes a light-transmitting upper cover, which is provided at one end of the first partition facing away from the bottom plate and is used to close the first accommodating cavity. By providing the light-transmitting upper cover at one end of the first partition facing away from the bottom plate, the first accommodating cavity can be closed to protect the compass, and at the same time, the light-transmitting property of the light-transmitting upper cover will not affect the image of the compass obtained by the imaging component.

[0012] In one embodiment, the magnetic induction box further includes a second partition, which is arranged on the side of the bottom plate facing away from the compass, and the second partition and the bottom plate are combined to form a second accommodating cavity corresponding to the first accommodating cavity, and the second partition is made of magnetic isolation material. By arranging the second partition on the side of the bottom plate facing away from the compass, the second accommodating cavity formed by the second partition and the bottom plate provides an accommodating space for the pad on the circuit backplane, and at the same time, the magnetic isolation property of the second partition makes the magnetic fields in the two adjacent second accommodating cavities not interfere with each other, thereby improving the detection accuracy of the detection device.

[0013] In one embodiment, the circuit backplane detection device further includes a judgment component, the judgment component includes a memory, a processor and a display electrically connected to each other, the memory is also electrically connected to the camera, the memory is used to store the initial image when the compass is in the initial position, the processor is used to compare the real-time image acquired by the camera in real time with the initial image, and obtain a comparison result based on whether the real-time image is the same as the initial image, and the display is used to display the comparison result. By setting the judgment component in the circuit backplane detection device, the judgment component automatically compares the changes in the direction of the compass, which improves the detection efficiency, saves labor costs, and has a higher detection accuracy rate compared to manual judgment.

[0014] Based on the same inventive concept, the present application also provides a circuit backplane detection method, wherein the circuit backplane detection method uses the circuit backplane detection device described in any of the above embodiments to perform detection, including:

[0015] Align the magnetic induction box with the circuit backplane;

[0016] Passing a variable current into the circuit backplane;

[0017] Using the imaging component to acquire an initial image and a real-time image of the compass;

[0018] The location of the bad point on the circuit backplane is determined according to the change in the direction of the compass on the real-time image.

[0019] By using the circuit backplane detection method provided in the embodiment of the present application to detect the circuit backplane before bonding the chip to the circuit backplane, it is helpful to reduce the difficulty of repair and reduce production costs. In addition, the detection method is simple to operate and easy to implement.

[0020] In one embodiment, aligning the magnetic sensing box with the back plate of the circuit to be detected includes:

[0021] The second partition of the magnetic induction box is fitted with the back plate of the circuit to be detected, and the multiple pad groups are accommodated in the multiple second accommodating cavities of the magnetic induction box in a one-to-one correspondence. The multiple compasses are arranged in a one-to-one correspondence with the multiple pad groups.

[0022] By making the second partition fit the back plate of the circuit to be detected and accommodating each group of first solder pads and second solder pads into the second accommodating cavity, the purpose of isolating each solder pad group by the second partition and avoiding interference of the magnetic field between two adjacent solder pad groups can be achieved; by arranging multiple compasses and multiple solder pad groups in a one-to-one correspondence, the purpose of enabling each compass to detect a first solder pad and a second solder pad accordingly can be achieved.

[0023] In one implementation, supplying a variable current to the circuit backplane includes:

[0024] A periodically increasing current is passed through the circuit backplane.

[0025] By increasing the current first and then suddenly changing it to a low level, a changing electric field is generated, which further generates a magnetic field, which causes the direction of the compass to deflect.

[0026] In one embodiment, the determining component determines the location of the bad point according to the direction of the compass on the image, including:

[0027] The determination component compares the direction of the compass on the real-time image with the direction of the compass on the initial image;

[0028] The judgment component outputs the bad point location information of the circuit backplane.

[0029] By enabling the judgment component to automatically detect the location of bad pixels, the detection efficiency is improved, labor costs are saved, and the detection accuracy is higher than that of manual judgment. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A schematic diagram of the structure of a circuit backplane detection device according to an embodiment;

[0031] Figure 2 A schematic diagram of the structure of a circuit backplane detection device according to another embodiment;

[0032] Figure 3 An initial image of a compass of one embodiment;

[0033] Figure 4 A real-time image of a compass of one embodiment;

[0034] Figure 5 A schematic diagram of current variation in an embodiment;

[0035] Figure 6 is a schematic diagram of an electric field of an embodiment;

[0036] Figure 7 A magnetic field schematic diagram of an embodiment;

[0037] Figure 8 The present invention is a flow chart of a circuit backplane detection method according to an embodiment.

[0038] Description of reference numerals:

[0039] 100-circuit backplane detection device;

[0040] 10-electromagnetic component, magnetic induction box-110, 111-bottom plate, 112-first partition, 113-first accommodating cavity, 114-second partition, 115-second accommodating cavity, 116-light-transmitting upper cover, 120-compass, 121-first compass, 122-second compass;

[0041] 20-imaging component, 210-camera, 220-light source;

[0042] 30-circuit back plate, 31-first solder pad, 32-second solder pad;

[0043] 40-judgment component, 41-memory, 42-processor, 43-display. DETAILED DESCRIPTION

[0044] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present application are given in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thoroughly and comprehensively understood.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0046] Micro-LED is a thin-film, miniaturized, arrayed LED (light-emitting diode) structure, with a size reduced to about 1 to 10 μm. After a large amount of transfer to the substrate, physical deposition is used to complete the protective layer and electrode, and then packaging is completed to complete the Micro-LED display. Micro-LED displays have good stability and long service life. At the same time, they also inherit the advantages of LED such as low power consumption, high color saturation, fast response speed, and strong contrast. They are widely used in wearable devices, ultra-large display screens, wireless optical communications and other fields.

[0047] During the production process of Micro-LED display panels, it is necessary to first transfer the LED chips from their respective growth substrates to the display panel. However, if any LED chip is damaged or has poor contact, a bad pixel will appear on the display panel after the transfer, affecting the imaging effect. The current structure of the Micro-LED display backplane drive circuit is only suitable for lighting up the LED chip after the massive transfer, and detecting the location of the bad pixel by detecting the outgoing light beam of the LED chip. However, sometimes, the cause of the bad pixel is not a problem with the LED chip, but damage to the display backplane, which causes the LED chip to fail to light up.

[0048] Based on this, the present application hopes to provide a solution that can solve the above-mentioned technical problems, the details of which will be described in the subsequent embodiments.

[0049] See also Figure 1 and Figure 2 The present application provides a circuit backplane detection device 100, the circuit board detection device 100 is used to detect the pad group of the circuit backplane, the pad group includes a first pad 31 and a second pad 32 arranged adjacent to each other, the first pad 31 and the second pad 32 are used to bond with the positive and negative electrodes of the LED chip. The circuit backplane detection device 100 includes: an electromagnetic component 10 and an imaging component 20. Among them, the electromagnetic component 10 includes a magnetic induction box 110 and a plurality of compasses 120, and the plurality of compasses 120 are fixed in the magnetic induction box 110. Specifically, the magnetic induction box 110 includes a bottom plate 111 and a plurality of first partitions 112, the plurality of first partitions 112 are arranged on the bottom plate 111 at intervals, and are enclosed with the bottom plate 111 to form a plurality of first accommodating cavities 113, and the plurality of compasses 120 are accommodated in the plurality of first accommodating cavities 113 in a one-to-one correspondence.

[0050] The imaging component 20 includes a camera 210, which includes an image sensor, such as a charge coupled device (CCD) or a complementary metal oxide semiconductor device (CMOS). The image sensor can perform photoelectric conversion and A / D (analog / digital) conversion on the optical signal of the incident light. The camera 210 is disposed on one side of the magnetic sensing box 110, and the camera 210 is used to shoot the electromagnetic component 10 to obtain the image of the compass 120 in real time, or it can also be converted into an electrical signal by the image sensor and transmitted to other electronic devices for display.

[0051] In this embodiment, the material of the first partition 112 is a magnetic isolation material, and the material of the bottom plate 111 is an opaque material that can be penetrated by the magnetic field. By making the first partition 112 a magnetic isolation material, it is possible to avoid the external magnetic field from interfering with the magnetic field in the first accommodating cavity 113, so that the direction of the compass 120 is deflected. By making the bottom plate 111 a material that can be penetrated by the magnetic field, when the magnetic field on the circuit back plate 30 changes, the changed magnetic field can penetrate the bottom plate 111 to change the direction of the compass 120. At the same time, by making the bottom plate 111 an opaque material, when the imaging component 20 acquires the image of the compass 120, the interference caused by the pads or circuits on the circuit back plate 30 is avoided, the problem of unclear imaging is avoided, and the detection accuracy is improved. For example, the magnetic isolation material can be a metal with strong ferromagnetism, and the material of the bottom plate 111 can be magnetic ceramics, etc., which is not specifically limited in the embodiment of the present application.

[0052] When the circuit backplane detection device 100 provided in the embodiment of the present application is used to detect the pads on the circuit backplane 30, the multiple compasses 120 are arranged in one-to-one correspondence with the multiple pad groups on the circuit backplane 30. When a changing current is passed through the first pad 31 and the second pad 32, the imaging component 20 shoots the multiple compasses 120 to obtain images of the multiple compasses 120 after the current is passed through the first pad 31 and the second pad 32. If the direction of the compasses 120 displayed on the image has changed compared to the initial position, it indicates that the first pad 31 and the second pad 32 are connected, and the first pad 31 and the second pad 32 are normal. If the direction of the compass 120 shown on the image is the same as the initial position, it means that there is no current flowing between the first solder pad 31 and the second solder pad 32, and the pad group is damaged, that is, there is at least one bad spot among the first solder pad 31, the second solder pad 32 and the conductive circuit connecting the first solder pad 31 and the second solder pad 32. Therefore, it is only necessary to further detect the first solder pad 31, the second solder pad 32 and the conductive circuit connecting the first solder pad 31 and the second solder pad 32 to determine the location of the bad spot.

[0053] By making the compass 120 in the circuit backplane 30 detection device 100 correspond to the first pad 31 and the second pad 32 on the circuit backplane 30, and the image of the compass 120 is obtained by the imaging component 20, when a changing current is passed through the first pad 31 and the second pad 32, the changing electric field generates a magnetic field, causing the direction of the compass 120 to change. If the image shows that the direction of the compass has changed, it means that the pad group is normal; if the image shows that the direction of the compass remains unchanged, it means that the pad group is damaged. According to the change in the direction of the compass 120, it can be determined whether the corresponding pad group is damaged, thereby realizing the detection of bad points on the circuit backplane 30 before chip bonding, which is conducive to reducing the difficulty of repair and reducing production costs.

[0054] In one implementation, see Figure 1 The magnetic induction box 110 further includes a light-transmitting upper cover 116, which is provided at one end of the first partition 112 facing away from the bottom plate 111, and is used to close the first accommodating cavity 113. The light-transmitting upper cover 116 may be made of glass or an organic polymer material, such as polymethyl methacrylate (PMMA). By providing the light-transmitting upper cover 116 at one end of the first partition 112 facing away from the bottom plate 111, the first accommodating cavity 113 can be closed to protect the compass 120, and at the same time, the light-transmitting property of the light-transmitting upper cover 116 will not affect the image of the compass 120 obtained by the imaging component 20.

[0055] In one implementation, see Figure 1 and Figure 2 , the magnetic induction box 110 also includes a second partition 114, which is arranged on the surface of the bottom plate 111 facing away from the compass 120. The second partition 114 and the bottom plate 111 are enclosed to form a second accommodating cavity 115, and the second partition 114 is arranged in a one-to-one correspondence with the first partition 112, so that the second accommodating cavity 115 is arranged in a one-to-one correspondence with the first accommodating cavity 113. Among them, the second partition 114 and the first partition 112 can be either a split structure or an integrated structure. Figure 3 As shown, when the second partition 114 and the first partition 112 are split structures, the number of the bottom plate 111 is one, and the first partition 112 can be installed on one surface of the bottom plate 111, and then the second partition 114 can be installed on the other surface of the bottom plate 111. Figure 5As shown, when the first partition 112 and the second partition 114 are an integrated structure, the number of the bottom plate 111 is multiple, and multiple one-to-one corresponding first accommodating cavities 113 and second accommodating cavities 115 can be separated by installing the bottom plate 111 between the multiple first partitions 112 and the second partitions 114. The second accommodating cavity 115 is used to accommodate the pad group on the circuit back plate 30. By setting the second accommodating cavity 115 and the first accommodating cavity 113 in one-to-one correspondence, the purpose of setting the compass 120 and the pad group in one-to-one correspondence can be achieved. Similarly, the second partition 114 is made of magnetic isolation material. By setting the second partition 114 on the surface of the bottom plate 111 facing away from the compass 120, the second accommodating cavity 115 formed by the second partition 114 and the bottom plate 111 provides an accommodating space for the pad on the circuit back plate 30. At the same time, the magnetic isolation characteristics of the second partition 114 make the magnetic fields in the two adjacent second accommodating cavities 115 not interfere with each other, thereby improving the detection accuracy of the detection device.

[0056] In one implementation, see Figure 2 The imaging component 20 also includes a light source 220, which is arranged on the side of the first partition 112 facing away from the bottom plate 111. When the detection environment is relatively dim, the image brightness and clarity obtained by the camera 210 under natural light are not enough, which will affect the judgment of the direction of the compass 120. At this time, the light source 220 can be turned on, and the light emitted by the light source 220 illuminates the area where the compass 120 is located. The light enters the camera 210 after being reflected by the transparent upper cover 116, which can achieve a fill light effect, which is beneficial to improve the brightness and clarity of the image. It can be understood that the light source 220 can be powered by a plug-in type or a battery, so that the circuit backplane detection device 100 can be suitable for different detection environments. By arranging the light source 220 in the imaging component 20, when the light in the detection environment is weak, turning on the light source 220 can improve the imaging clarity, thereby expanding the scope of application of the road backplane detection device 100.

[0057] In one implementation, see Figures 1 to 4The circuit backplane detection device 100 further includes a judgment component 40, which is electrically connected to the imaging component 20 to automatically judge the position of the damaged pad according to the image. Specifically, the judgment component 40 includes a memory 41, a processor 42 and a display 43 which are electrically connected to each other. The memory 41 can be a RAM memory, a disk memory, etc. The processor 42 can be a CPU (central processing unit) which can perform calculations on various electrical signals. The display 43 can be an LCD display, an LED display, etc. The memory 41 is electrically connected to the camera 210. After the camera 210 obtains the image of the compass 120, the optical signal is converted into a first electrical signal through an image sensor and sent to the memory 41, and the memory 41 stores the first electrical signal. Among them, the camera 210 obtains the image of the compass 120, including obtaining an initial image of the compass 120 at an initial position before current is applied to the first pad 31 and the second pad 32, and obtaining a real-time image of the compass 120 obtained in real time after current is applied to the first pad 31 and the second pad 32. The memory 41 is electrically connected to the processor 42. The memory 41 receives the first electrical signal and further transmits it to the processor 42. The processor 42 is used to compare the real-time image acquired by the camera 210 with the initial image, and obtain a comparison result based on whether the real-time image of the camera 210 is the same as the initial image, and transmit the comparison result to the display 43. The display 43 is used to display the comparison result. Among them, when the directions of all compasses 120 in the real-time image acquired by the camera 210 in real time are different from those in the initial image, the comparison result is that the circuit backplane 30 is normal. When the direction of the compass 120 in the real-time image acquired by the camera 210 is the same as the direction of the compass 120 in the initial image, the processor 42 can determine the position of the compass 120 with unchanged direction, and output the coordinate value of the compass 120, which represents the specific row and column position of the compass 120, that is, the row and column position where the bad point is located.

[0058] For example, when no current flows through the circuit backplane 30, the direction of the compass 120 is the same as the direction of the earth's magnetic field, and the initial image is as follows: Figure 5 When a variable current is passed into the circuit backplane 30, the image captured by the camera 210 in real time is as shown in FIG. Figure 6 As shown, compared Figure 5 and Figure 6 It can be seen that the directions of the first compass 121 and the second compass 122 have not changed, the directions of other compasses 120 are perpendicular to the original directions, and the first compass 121 is located in the second row and second column, and the second compass 122 is located in the third row and third column. Therefore, in the final result output by the display 43, the coordinate values ​​of the bad points are (2, 2) and (3, 3).

[0059] Alternatively, the comparison result can also be presented on the display 43 in the form of an image, such as directly Figure 6 The positions of the first compass 121 and the second compass 122 are marked. By setting the judgment component 40 in the circuit backplane detection device 100, the judgment component 40 automatically compares the change of the direction of the compass 120, which improves the detection efficiency, saves labor costs, and has a higher detection accuracy compared to manual judgment.

[0060] It is understandable that the circuit backplane detection device 100 provided in the embodiment of the present application includes but is not limited to the above-mentioned structure. For example, it may also include an operation terminal and a controller, the operation terminal may be a mouse, a keyboard, a touch screen, etc., the controller may be used to control the opening and closing of the camera 210 in the circuit backplane detection device 100, the opening and closing of the power supply, the change of the current size passed into the circuit backplane 30, the power-on time, etc., and the technician may set the program of the circuit backplane detection device 100 in real time through the operation terminal.

[0061] Based on the same inventive concept, the present application also provides a circuit backplane detection method, please refer to Figure 2 and Figure 8 The circuit backplane detection method uses the circuit backplane detection device 100 provided in any of the above embodiments to perform detection, including:

[0062] Step S1, aligning the magnetic induction box 110 with the circuit back plate 30;

[0063] Step S2, supplying a variable current to the circuit backplane 30;

[0064] Step S3, using the imaging component 20 to acquire an initial image and a real-time image of the compass 120;

[0065] Step S4, determining the location of the bad point on the circuit back plate 30 according to the change in the direction of the compass 120 on the real-time image.

[0066] By inspecting the circuit backplane 30 using the circuit backplane inspection method provided in the embodiment of the present application before bonding the chip to the circuit backplane 30, compared with inspecting after bonding the chip to the circuit backplane 30, it is helpful to reduce the difficulty of repair and reduce production costs, and the inspection method is simple to operate and easy to implement.

[0067] In one implementation, see Figure 1 and Figure 8 In step S1, aligning the magnetic induction box 110 with the circuit back plate 30 includes:

[0068] Step S11, the second partition 114 of the magnetic induction box 110 is fitted with the circuit back plate 30, so that each group of first pads 31 and second pads 32 for bonding with the LED chip are accommodated in a one-to-one correspondence in a plurality of second accommodating cavities 115 of the magnetic induction box 110, and each compass 120 corresponds to a group of first pads 31 and second pads 32. By fitting the second partition 114 with the circuit back plate 30, and accommodating each pad group in a one-to-one correspondence in a plurality of second accommodating cavities 115, the purpose of isolating two adjacent pad groups through the second partition 114 is achieved to avoid mutual interference of magnetic fields between different pad groups. By making each compass 120 correspond to a pad group, the purpose of detecting multiple compasses 120 in a one-to-one correspondence with multiple pad groups is achieved.

[0069] In one implementation, see Figure 1 , Figures 5 to 7 , passing a variable current into the circuit backplane 30 includes: passing a periodically increasing current into the circuit backplane 30. Exemplarily, the method of periodically increasing the current is:

[0070] Step S21, increasing the current first;

[0071] Step S22, causing the current to suddenly change to a low level;

[0072] Step S23, the current is increased again and the cycle is repeated.

[0073] like Figure 5 The figure shows a schematic diagram of current change, where the horizontal axis T represents time, and its unit is seconds, represented by S, and the vertical axis I represents the current size, and its unit is ampere, represented by A. In the time period t1-t2, the current passing through the circuit backplane 30 is increased from zero to I1 to generate a directional magnetic field. At the moment t2-t3, the current is suddenly changed from the high position I1 to the low position I2. At this time, due to the small potential difference, a small magnetic field in the opposite direction is generated. At this time, the magnetic force has little effect on the chip, and the first pad 31 and the second pad 32 have a potential difference to form a magnetic field. Figure 6 The changing electric field further causes Figure 7 The magnetic field shown in the figure is perpendicular to the direction of the earth's magnetic field, so that the direction of the compass 120 changes. Then, by increasing the current again and repeating this cycle, the compass 120 can be kept in the changing magnetic field, so that the camera 210 can obtain the changing image of the compass 120 in real time.

[0074] In one implementation, see Figure 2 and Figure 8 , using the imaging component 20 to obtain an image of the compass 120 includes:

[0075] Step S31, lighting the light source 220 so that the light emitted by the light source 220 illuminates the area where the compass 120 is located, which is beneficial to improving the imaging clarity;

[0076] Step S32, turning on the camera 210, the camera 210 captures an initial image of the compass 120 before the circuit back plate 30 passes a changing current, and a real-time image of the compass 120 after the circuit back plate 30 passes a changing current.

[0077] Specifically, starting the camera 210 in step S32 includes:

[0078] Before the circuit back plate 30 is supplied with a changing current, the camera 210 is turned on once, and the camera 210 captures an initial image of the compass 120;

[0079] After the changed current is passed into the circuit backplane 30 , the camera 210 is turned on again, and the camera 210 captures a real-time image of the compass 120 .

[0080] By making the camera 210 respectively capture the initial image of the compass 120 before the changing current is passed through the circuit back plate 30 and the image after the current is passed through, the purpose of comparing the change in the direction of the compass 120 can be achieved.

[0081] In one implementation, see Figure 2 and Figure 8 In step S4, the determination component 40 determines the location of the bad point according to the direction of the compass 120 on the image, including:

[0082] Step S41, the determination component 40 compares the direction of the compass 120 on the real-time image with the direction of the compass 120 on the initial image;

[0083] Step S42, the judgment component 40 outputs the bad pixel position information of the circuit backplane 30. Specifically, the camera 210 converts the captured initial image and real-time image into a first electrical signal and transmits it to the processor 42. The processor 42 compares the real-time image with the initial image, and converts the processing result into a second electrical signal and transmits it to the display 43. After receiving the second electrical signal, the display 43 displays the display result. Among them, when the direction of the compass 120 in the real-time image is the same as the direction of the compass 120 in the initial image, the display 43 shows that the circuit backplane 30 is normal. When the direction of the compass 120 in the real-time image is different from the direction of the compass 120 in the initial image, the processor 42 further determines the position information of the compass 120 with a changed direction, and the display 43 displays the comparison result by marking the position of the compass 120 with a changed direction or directly giving its coordinate value. By making the judgment component 40 automatically detect the bad pixel position, compared with manual judgment, the detection efficiency is improved, the labor cost is saved, and the detection accuracy is higher.

[0084] It should be understood that the application of the present invention is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A circuit backplane detection device, used for detecting a pad group of a circuit backplane, wherein the pad group includes a first pad and a second pad for bonding with an LED chip, characterized in that: include: An electromagnetic assembly, the electromagnetic assembly comprising a magnetic induction box and a plurality of compasses, wherein the plurality of compasses are fixed in the magnetic induction box; the magnetic induction box is placed on the circuit backplane so that each compass corresponds to one of the pad groups; An imaging component, the imaging component comprising a camera, the camera being disposed on one side of the magnetic induction box, the camera being used to acquire an image of the compass, wherein the image of the compass comprises an initial image and a real-time image of the compass; A judgment component is used to compare the direction of the compass in the real-time image with the direction of the compass in the initial image to determine the location of the bad point on the circuit backplane; the judgment component is connected to the imaging component.

2. The circuit backplane detection device according to claim 1, characterized in that: The magnetic induction box includes a bottom plate and a plurality of first partitions, wherein the plurality of first partitions are arranged on the bottom plate at intervals, and the bottom plate and the plurality of first partitions are combined to form a plurality of first accommodating cavities, wherein the plurality of compasses are accommodated in the plurality of first accommodating cavities one by one.

3. The circuit backplane detection device according to claim 2, characterized in that: The material of the first partition is a magnetic isolation material, and the material of the bottom plate is a light-proof material that can penetrate the magnetic field.

4. The circuit backplane detection device according to claim 2, characterized in that: The magnetic induction box body further comprises a light-transmitting upper cover, which is arranged on an end of the first partition plate facing away from the bottom plate and is used to close the first accommodating cavity.

5. The circuit backplane detection device according to claim 2, characterized in that: The magnetic induction box also includes a second partition, which is arranged on the side of the bottom plate facing away from the compass. The second partition and the bottom plate are combined to form a second accommodating cavity corresponding to the first accommodating cavity. The second partition is made of magnetic isolation material.

6. The circuit backplane detection device according to any one of claims 1 to 5, characterized in that: The judgment component includes a memory, a processor and a display that are electrically connected to each other. The memory is also electrically connected to the camera. The memory is used to store an initial image when the compass is in an initial position. The processor is used to compare the real-time image acquired by the camera in real time with the initial image, and obtain a comparison result based on whether the real-time image is the same as the initial image. The display is used to display the comparison result.

7. A circuit backplane detection method, characterized in that: The circuit backplane detection device according to any one of claims 1 to 6 is used for detection, comprising: Aligning the magnetic induction box with the circuit backplane; Passing a variable current into the circuit backplane; Using the imaging component to acquire an initial image and a real-time image of the compass; The location of the bad point on the circuit backplane is determined according to the direction of the compass on the real-time image.

8. The circuit backplane detection method according to claim 7, characterized in that: Aligning the magnetic induction box with the back plate of the circuit to be detected includes: The second partition of the magnetic induction box is fitted with the back plate of the circuit to be detected, and the multiple pad groups are accommodated in the multiple second accommodating cavities of the magnetic induction box in a one-to-one correspondence. The multiple compasses are arranged in a one-to-one correspondence with the multiple pad groups.

9. The circuit backplane detection method according to claim 8, characterized in that: The changing current introduced into the circuit backplane includes: A periodically increasing current is passed through the circuit backplane.

10. The circuit backplane detection method according to claim 9, characterized in that: Determining the location of the bad point according to the direction of the compass on the image includes: The judging component of the detection device compares the direction of the compass on the real-time image with the direction of the compass on the initial image; The judgment component outputs the bad point location information of the circuit backplane.

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