PCB structure of LED display screen

Abstract

The utility model discloses a PCB (printed circuit board) structure of an LED (light-emitting diode) display screen, which comprises a substrate and a metal pattern layer arranged on the substrate, the metal pattern layer is provided with a bonding pad area and a non-bonding pad area, and the PCB structure is characterized by further comprising a solder mask arranged between the bonding pad area and the non-bonding pad area and used for isolating the bonding pad area from the non-bonding pad area; according to the PCB structure of the LED display screen provided by the utility model, the solder mask strip is arranged between the bonding pad area and the non-bonding pad area of the metal pattern layer, so that the two areas can be effectively isolated. Therefore, the soldering tin can be prevented from diffusing to the non-bonding pad area in the welding process, the welding quality is improved, meanwhile, it is ensured that liquid substances can flow smoothly in the underfilling technology, and the display effect and ink color uniformity of the LED display screen are improved.

Description

Technical Field

[0001] This utility model relates to the field of display screen technology, and in particular to a PCB board structure for an LED display screen. Background Technology

[0002] With the continuous development of LED display technology, especially the rise of Mini / Micro LED technology, higher requirements have been placed on the manufacturing process of PCB boards. In the current LED display manufacturing process, the solder mask treatment of the PCB board's lamp side surface typically employs the following two methods:

[0003] Option 1: Apply solder mask to the entire PCB surface except for the solder pads. While this option effectively prevents solder from spreading to non-pad areas during soldering, the presence of the solder mask layer reduces the fluidity of the liquid substance during secondary surface treatment (such as underfill). This results in poor uniformity of surface thickness after self-leveling and curing, leading to uneven ink color and display effect in the LED display.

[0004] Option 2: No solder mask treatment on the entire PCB. While this option ensures the fluidity of the liquid material during the underfill process, the solder on the pads can easily spread to non-pad areas during the LED chip soldering process, causing poor LED chip soldering and resulting in a defective LED screen display.

[0005] Therefore, there is a contradiction between the solder mask treatment and the welding process in the existing PCB board structure, which cannot simultaneously meet the requirements of good underfill flow and welding quality. Utility Model Content

[0006] The technical problem to be solved by this utility model is to provide a PCB board structure for LED displays to solve the problem that there is a contradiction between the solder mask treatment and the welding process in the existing PCB board structure, which cannot simultaneously meet the requirements of good underfill flow and welding quality.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows: a PCB board structure for an LED display screen, including a substrate and a metal pattern layer disposed on the substrate, the metal pattern layer having a pad area and a non-pad area, and further including a solder resist strip, the solder resist strip being disposed between the pad area and the non-pad area for isolating the pad area and the non-pad area.

[0008] Furthermore, the longitudinal cross-sectional shape of the welding resist is rectangular, trapezoidal, semi-circular, or semi-elliptical.

[0009] Furthermore, the thickness of the resist electrode is 0.01-0.1 mm.

[0010] Furthermore, the thickness of the solder resist is 0.02 mm.

[0011] Furthermore, the material of the welding resist electrode is a high-temperature resistant material.

[0012] Furthermore, the material of the solder resist is epoxy resin or polyimide.

[0013] Furthermore, the bottom of the solder resist electrode near the pad area has a capillary structure.

[0014] Furthermore, the capillary structure consists of multiple micropores disposed on the solder resist electrode.

[0015] Furthermore, the capillary structure is a groove provided in the solder resist strip.

[0016] Furthermore, the capillary structure is provided on the folded edge of the solder resist electrode.

[0017] The beneficial effects of this utility model are as follows: The PCB board structure of the LED display screen provided by this utility model can effectively isolate the two areas by setting a solder resist strip between the solder pad area and the non-solder pad area of ​​the metal pattern layer. This can prevent solder from spreading to the non-solder pad area during the soldering process, improve the soldering quality, and at the same time ensure that the liquid material in the underfill process can flow smoothly, improving the display effect and ink uniformity of the LED display screen. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the PCB board structure of the LED display screen according to Embodiment 1 of this utility model;

[0019] Figure 2 This is a partial cross-sectional schematic diagram of the PCB board structure of the LED display screen according to Embodiment 1 of this utility model;

[0020] Figure 3 This is a partial cross-sectional schematic diagram of the PCB board structure of the LED display screen according to Embodiment 2 of this utility model;

[0021] Figure 4 This is a partial cross-sectional schematic diagram of the PCB board structure of the LED display screen according to Embodiment 3 of this utility model;

[0022] Figure 5 This is a partial cross-sectional schematic diagram of the PCB board structure of the LED display screen according to Embodiment 4 of this utility model.

[0023] Label Explanation:

[0024] 1. Substrate; 2. Metal pattern layer; 21. Pad area; 22. Non-pad area; 3. Solder resist; 4. Microvia; 5. Groove; 6. Folded edge. Detailed Implementation

[0025] To explain in detail the technical content, objectives, and effects of this utility model, the following description is provided in conjunction with the embodiments and accompanying drawings.

[0026] Please refer to Figures 1 to 5 A PCB board structure for an LED display screen includes a substrate 1 and a metal pattern layer 2 disposed on the substrate 1. The metal pattern layer 2 has a pad area 21 and a non-pad area 22, and also includes a solder resist 3 disposed between the pad area 21 and the non-pad area 22 to isolate the pad area 21 and the non-pad area 22.

[0027] As can be seen from the above description, the beneficial effects of this utility model are as follows: by setting the solder resist strip 3 between the solder pad area 21 and the non-solder pad area 22 of the metal pattern layer 2, these two areas can be effectively isolated. This can prevent solder from spreading to the non-solder pad area 22 during the soldering process, improving the soldering quality, while ensuring that the liquid material in the underfill process can flow smoothly, improving the display effect and ink uniformity of the LED display screen.

[0028] Furthermore, the longitudinal cross-sectional shape of the welding resist 3 is rectangular, trapezoidal, semi-circular, or semi-elliptical.

[0029] As described above, the longitudinal cross-sectional shape of the solder resist electrode 3 is designed to be rectangular, trapezoidal, semi-circular, or semi-elliptical, which can better adapt to different pad layouts and process requirements. For example, a trapezoidal cross-section helps guide solder flow and prevent solder diffusion, while a semi-circular or semi-elliptical cross-section is beneficial for improving the fluidity in the underfill process, thereby improving the process effect.

[0030] Furthermore, the thickness of the resist electrode 3 is 0.01-0.1 mm.

[0031] As described above, the thickness of the solder resist 3 is set to 0.01-0.1mm. This spacing ensures that solder will not overflow into the non-pad area 22 during the soldering process, while also not affecting the flow of liquid substances in the underfill process. This spacing range is optimized to balance the requirements of soldering quality and the underfill process.

[0032] Furthermore, the thickness of the resist electrode 3 is 0.02 mm.

[0033] As can be seen from the above description, setting the thickness of the welding resist 3 to 0.02mm is the optimal solution obtained based on extensive experiments and practice, which can provide the best welding quality and underfill process effect.

[0034] Furthermore, the material of the resist electrode 3 is a high-temperature resistant material.

[0035] As can be seen from the above description, the welding resist electrode 3 is made of high-temperature resistant material, which can withstand high temperatures during the welding process, preventing the welding resist electrode 3 from deforming or being damaged, thereby ensuring its stability and reliability in high-temperature environments.

[0036] Furthermore, the material of the solder resist 3 is epoxy resin or polyimide.

[0037] As described above, epoxy resin or polyimide not only has high temperature resistance, but also good chemical corrosion resistance and mechanical strength, which can adapt to various harsh conditions in welding and underfilling processes, ensuring the long-term stability and reliability of PCB boards.

[0038] Furthermore, the bottom of the solder resist 3 near the solder pad area 21 is provided with a capillary structure.

[0039] As described above, a capillary structure is provided at the bottom of the solder resist 3 on the side near the pad area 21, which utilizes capillary action to control the flow of solder. This design effectively prevents solder from spreading to the top of the solder resist 3, thereby further improving the soldering quality.

[0040] Furthermore, the capillary structure consists of multiple micropores 4 disposed on the solder resist 3.

[0041] As described above, the capillary structure is designed with multiple micro-holes 4. These micro-holes 4 can precisely control the flow path of the solder, prevent the solder from spreading disorderly, and at the same time do not affect the fluidity of the liquid material in the underfill process.

[0042] Furthermore, the capillary structure is a groove 5 provided in the solder resist 3.

[0043] As described above, the capillary structure is designed as groove 5. Groove 5 can guide the solder to flow along a specific path, reduce the accumulation of solder in the non-pad area 22, and improve the accuracy and reliability of soldering.

[0044] Furthermore, the capillary structure is provided on the folded edge 6 of the solder resist 3.

[0045] As described above, the capillary structure is designed with a folded edge 6. The folded edge 6 can enhance the adhesion between the solder and the solder resist 3. At the same time, it uses capillary action to control the flow of the solder, ensuring that the solder does not spread to unwanted areas, and further optimizes the soldering effect.

[0046] Please refer to Figure 1 and Figure 2One embodiment of this utility model is: a PCB board structure for an LED display screen, including a substrate 1 and a metal pattern layer 2 disposed on the substrate 1. The metal pattern layer 2 is made of copper and has pad areas 21 and non-pad areas 22. The pad areas 21 are used for soldering LED beads / LED light-emitting chips. The PCB board structure for the LED display screen also includes a solder resist strip 3, which is disposed between the pad areas 21 and the non-pad areas 22 to isolate them. It can be understood that by setting the solder resist strip 3 between the pad areas 21 and the non-pad areas 22 of the metal pattern layer 2, these two areas can be effectively isolated. This prevents solder from spreading to the non-pad areas 22 during the soldering process, improving soldering quality, and ensuring smooth flow of liquid substances in the underfill process, thereby improving the display effect and ink uniformity of the LED display screen.

[0047] Optionally, the longitudinal cross-sectional shape of the welding resist 3 can be rectangular (e.g., ...). Figure 2 As shown, the longitudinal cross-sectional shape of the solder resist 3 is designed as rectangular, trapezoidal, semi-circular, or semi-elliptical to better adapt to different pad layouts and process requirements. For example, a trapezoidal cross-section helps guide solder flow and prevent solder diffusion, while a semi-circular or semi-elliptical cross-section is beneficial for improving the fluidity in the underfill process, thereby improving the process effect.

[0048] Optionally, the thickness of the solder resist 3 is 0.01-0.1 mm. This thickness ensures that solder does not overflow into the non-pad area 22 during the soldering process, while also not affecting the flow of liquid material in the underfill process. This spacing range is optimized to balance the requirements of soldering quality and the underfill process. Preferably, the thickness of the solder resist 3 is 0.02 mm. This specific value is the optimal solution obtained based on extensive experiments and practice, providing the best soldering quality and underfill process effect.

[0049] Optionally, the solder resist 3 is made of a high-temperature resistant material, which can prevent the solder resist 3 from deforming or being damaged, thereby ensuring its stability and reliability in high-temperature environments. Specifically, the solder resist 3 is preferably made of epoxy resin or polyimide. Epoxy resin or polyimide not only has high-temperature resistance but also good chemical corrosion resistance and mechanical strength, which can adapt to various harsh conditions in the welding and underfilling processes, ensuring the long-term stability and reliability of the PCB board. In other embodiments, the high-temperature resistant material can also be acrylic resin, polyurethane-modified epoxy resin, polyimide oligomer, etc. In addition, the material of the solder resist 3 can also be green solder resist ink, white solder resist ink, black solder resist ink, low profile liquid photosensitive solder resist material, or dry film solder resist material; green solder resist ink is a common PCB solder resist material with good insulation and corrosion resistance. It can provide uniform surface coverage and prevent solder from spreading to non-pad areas; white solder resist ink is often used in LED applications because it can ensure that the light emitted by the LED is correctly reflected on the PCB surface, thereby improving the display effect; black solder resist ink has extremely strong light absorption, reduces reflection, and improves the luminous efficiency of LED; low profile liquid photosensitive solder resist material is economical and can provide precise feature dimensions and gaps, making it suitable for surface mount applications, especially performing well in close-pitch applications; dry film solder resist material has a larger thickness and is suitable for some surface mount products.

[0050] Please refer to Figure 3 Embodiment 2 of this utility model is a further improvement on the solder resist 3 based on Embodiment 1. The difference between Embodiment 2 and Embodiment 1 is that the bottom of the solder resist 3 near the pad area 21 has a capillary structure, which allows for control of solder flow using capillary action. This design effectively prevents solder from spreading to the top of the solder resist 3, thereby further improving the welding quality. Specifically, in this embodiment, the capillary structure consists of multiple micro-holes 4 on the solder resist 3. These micro-holes 4 can precisely control the flow path of the solder, preventing disordered diffusion of the solder, while not affecting the fluidity of the liquid material in the underfill process. The pore size of the micro-holes 4 can be selected from 10nm to 100nm. A pore size within this range can ensure that the liquid forms a stable liquid surface within the pore, thereby generating capillary action. In other embodiments, the micro-holes 4 can also be selected with other suitable pore sizes according to the welding conditions, materials, and other actual conditions, and are not limited to this.

[0051] Please refer to Figure 4The third embodiment of this utility model is a further improvement on the solder resist 3 based on the first embodiment. The difference between the third embodiment and the first embodiment is that the bottom of the solder resist 3 near the pad area 21 is provided with a capillary structure. Specifically, the capillary structure is a groove 5 provided in the solder resist 3. The groove 5 can guide the solder to flow along a specific path, reduce the accumulation of solder in the non-pad area 22, and improve the accuracy and reliability of the soldering.

[0052] Please refer to Figure 5 Embodiment 4 of this utility model is a further improvement on the solder resist 3 based on Embodiment 1. The difference between Embodiment 4 and Embodiment 1 is that the bottom of the solder resist 3 near the pad area 21 is provided with a capillary structure. Specifically, the capillary structure is provided on the folded edge 6 of the solder resist 3. The folded edge 6 can enhance the adhesion between the solder and the solder resist 3, and at the same time use the capillary phenomenon to control the flow of the solder, ensuring that the solder will not spread to unwanted areas, and further optimize the welding effect.

[0053] In summary, the PCB board structure for LED displays provided by this utility model effectively isolates the pad and non-pad areas of the PCB board by setting a solder resist strip between them, preventing solder from spreading to the non-pad area during the soldering process. This avoids problems such as short circuits and poor soldering, thus improving soldering quality. The design of the solder resist strip ensures that the solder flows only to the predetermined solder joints, reducing soldering defects such as cold solder joints, poor solder joints, or uneven solder joints, thereby improving the accuracy and quality of soldering. The solder resist strip can enhance the mechanical strength of the PCB board to a certain extent, especially in multilayer boards, acting as part of the interlayer insulation and improving overall stability. The design of the solder resist strip ensures that the liquid material in the underfill process can flow smoothly and evenly cover the entire non-pad area, thereby improving the uniformity of the surface thickness after curing and improving the consistency of the LED display's color and display effect. The bottom of the solder resist strip near the pad area has a capillary structure, which allows for control of solder flow using capillary action. This design effectively prevents solder from spreading to the top of the solder resist strip, further improving soldering quality.

[0054] The above description is merely an embodiment of this utility model and does not limit the patent scope of this utility model. Any equivalent modifications made based on the content of this utility model specification and drawings, or direct or indirect applications in related technical fields, are similarly included within the patent protection scope of this utility model.

Claims

1. A PCB board structure for an LED display screen, comprising a substrate and a metal pattern layer disposed on the substrate, the metal pattern layer having pad areas and non-pad areas, characterized in that, It also includes a solder resist electrode, which is disposed between the pad area and the non-pad area to isolate the pad area from the non-pad area.

2. The PCB board structure of the LED display screen according to claim 1, characterized in that, The longitudinal cross-sectional shape of the welding resist electrode is rectangular, trapezoidal, semi-circular, or semi-elliptical.

3. The PCB board structure of the LED display screen according to claim 1, characterized in that, The thickness of the welding resist is 0.01mm-0.1mm.

4. The PCB board structure of the LED display screen according to claim 3, characterized in that, The thickness of the resist electrode is 0.02 mm.

5. The PCB board structure of the LED display screen according to claim 1, characterized in that, The material of the welding resist electrode is a high-temperature resistant material.

6. The PCB board structure of the LED display screen according to claim 5, characterized in that, The material of the solder resist electrode is epoxy resin or polyimide.

7. The PCB board structure of the LED display screen according to claim 1, characterized in that, The bottom of the solder resist electrode near the pad area has a capillary structure.

8. The PCB board structure of the LED display screen according to claim 7, characterized in that, The capillary structure consists of multiple micropores disposed on the solder resist electrode.

9. The PCB board structure of the LED display screen according to claim 7, characterized in that, The capillary structure is a groove provided in the solder resist electrode.

10. The PCB board structure of the LED display screen according to claim 7, characterized in that, The capillary structure is a folded edge provided on the solder resist electrode.

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