LED panel shielding structure with safety protection function

Abstract

This utility model relates to electromagnetic shielding technology in the field of LED displays, and discloses an LED panel shielding structure with safety protection function, including a top layer, a bottom layer, and an internal signal layer. The top layer adopts a continuous copper ground layer, and all signal lines are led out from the chip and immediately pass through vias into the internal layer to ensure that the top layer forms a complete shielding layer. The bottom layer is covered with a grid-like copper foil, and the LED light-emitting devices are embedded in the grid, maintaining a safe distance of at least 3 mil between the LED pads and the grid, together forming the bottom layer shielding layer. A ring-shaped ground wire and an array of vias with a spacing of 0.3 mm are set on the periphery of the PCB to form a sidewall shielding structure. This box-shaped shielding structure is connected to the metal shell through conductive components to form a complete Faraday cage. This utility model achieves integrated electromagnetic shielding of the PCB itself, significantly suppressing electromagnetic radiation and external interference, taking into account heat dissipation and LED light transmission requirements, eliminating the need for an external shielding cover, reducing costs and improving reliability.

Description

Technical Field

[0001] This utility model relates to the field of electromagnetic shielding technology, specifically to an LED panel shielding structure with safety protection function. Background Technology

[0002] With the widespread application of LED technology in commercial displays, outdoor displays, and dome screen designs, electromagnetic interference (EMI) issues are becoming increasingly prominent. Electromagnetic radiation generated by high-frequency drive circuits not only affects the normal operation of surrounding electronic equipment but can also cause problems such as color distortion and unstable signal transmission in LED displays, and in severe cases, even trigger system-level electromagnetic compatibility failures.

[0003] Currently, some technologies use metal shielding covers to cover driving circuits or sensitive components, physically isolating them to block electromagnetic radiation. This type of solution relies on mechanical clips or screws to fix the shielding cover to the PCB. While this can improve shielding effectiveness in the short term, long-term use can lead to deformation of the shielding cover due to mechanical stress. Oxidation or dust accumulation at the joint surfaces can create micro-gaps, allowing high-frequency electromagnetic waves to leak through these gaps. Furthermore, LED displays need to emit light outwards, so metal shielding (usually using metal instead of plastic covers) is only suitable for situations where the pixel pitch is large and there is room for the metal shielding cover between pixels. In addition, repeated disassembly and reassembly of the shielding cover during equipment maintenance accelerates fatigue of the clip structure, ultimately leading to a significant increase in contact impedance between the shielding body and the PCB, and a gradual decrease in shielding effectiveness.

[0004] Other technologies enhance shielding by laminating metal foil (such as copper or aluminum) or coating the PCB surface with conductive coatings (such as silver paste or carbon nanotubes). Although the metal layer can reflect some electromagnetic waves, the difference in thermal expansion coefficients between it and the PCB substrate can cause stress cracks at the interface during high and low temperature cycling, forming hidden electromagnetic leakage channels. More seriously, the added metal layer significantly increases the weight of the PCB (especially in large-size displays) and requires additional etching or spraying processes, leading to increased production costs. Furthermore, any shielding material added to the LED display surface may affect the light emission pattern and display performance.

[0005] In addition, some designs attempt to optimize the distribution of wiring layers to reduce radiation, but the surface fine-line circuits will still form an equivalent antenna effect at high frequencies, making it difficult to completely eliminate interference.

[0006] Currently, the problem we need to solve is how to achieve electromagnetic shielding for ultra-small pixel pitches when the pixel pitch is extremely small, without affecting the display effect of the screen, and when there is no possibility of installing a mask. Utility Model Content

[0007] In view of this, the present invention provides an LED panel shielding structure with safety protection function to solve the problem of PCB electromagnetic shielding.

[0008] In a first aspect, this utility model provides an LED panel shielding structure with safety protection function, comprising: Top layer and bottom layer, wherein the top layer is a continuous copper grounding layer; An internal signal layer is embedded between the top layer and the bottom layer; Multiple vias penetrating each layer; The peripheral shielding structure is composed of ground wires and an array of vias connecting the layers, which are arranged around the outer ring of the top layer and the inner signal layer. The bottom surface is covered with a grid-like copper sheet, and LED light-emitting devices are embedded in the grid. The grid-like copper sheet and the LED light-emitting devices together form the bottom shielding layer.

[0009] This LED panel shielding structure, featuring safety protection, forms a fully enclosed shielding cavity (Faraday cage) on the top, bottom, and sides. The continuous copper layer on the top and the grid copper layer on the bottom provide face-to-face shielding, while the surrounding via walls effectively suppress electromagnetic energy leakage from the board edges. This structure confines most of the electromagnetic radiation generated by the LED display under high-frequency operation within the cavity, significantly reducing external electromagnetic emissions (EMI). The bottom layer uses a grid copper layer instead of a solid copper layer, balancing shielding and light transmission. The openings between the grids allow LED light to pass through smoothly, avoiding the obstruction of light by a solid copper layer and ensuring the brightness and uniformity of the display. Simultaneously, the grid copper layer still provides good high-frequency grounding and shielding.

[0010] In one alternative implementation, all signal lines of the top layer are led out of the chip and then transferred to the internal signal layer through the vias.

[0011] After the signal lines are led out of the chip, they immediately pass through vias into the inner layers, leaving only a continuous copper ground plane and chip pads on the top layer. This increases copper coverage and prevents exposed traces from disrupting the continuity of the top layer's shielding, thus enhancing the reflection capability of high-frequency electromagnetic waves. Furthermore, the absence of long-term exposed signal lines on the top layer completely eliminates the equivalent antenna effect of surface traces at high frequencies.

[0012] In one alternative embodiment, the ground line width of the peripheral shielding structure is less than or equal to half the pixel pitch, and the vias are arranged in an array along the edge with a spacing of less than 1 mm between adjacent vias.

[0013] The ground wire width is determined based on the pixel pitch of the LED display (i.e., the center-to-center distance between adjacent LED light-emitting devices), and is controlled to be ≤ half the pixel pitch. For example, when the pixel pitch of the display is 4mm, the peripheral ground wire width is set to 2mm; when the pixel pitch is 2mm, the ground wire width is set to 1mm, ensuring that the ground wire layout does not encroach on the installation space of the LED devices, while adapting to the structural constraints of different sized displays. Vias are laser-drilled vias, arranged in an array along the peripheral edge of the PCB. The spacing between adjacent vias is set to 0.3mm, and the vias are electrically connected to the peripheral ground wire, forming a closed via array. The peripheral ground wires of the top layer, internal signal layer, and bottom layer achieve interlayer electrical connection through the above via array, forming a continuous peripheral shielding wall. The top ground wire of the shielding wall and the edge of the bottom mesh copper foil extend together to the edge of the PCB board, connecting with the external metal enclosure, ensuring that the peripheral shielding structure is integrated with the external grounding system.

[0014] In one optional embodiment, the LED panel shielding structure with safety protection function is box-shaped, and this LED panel shielding structure with safety protection function is electrically connected to the metal box shell through conductive components.

[0015] In one alternative embodiment, the bottom surface is provided with metallized holes, and the LED tube is electrically connected to the internal signal layer through the metallized holes.

[0016] Metallized vias provide a robust, electroplated metal connection that is far more reliable than jumpers or other connection methods. They establish the shortest and most direct electrical path between the LED and the internal driver circuitry, reducing connection impedance and the risk of introducing interference.

[0017] Through precise layout design, the connection points (metallized vias) are integrated into the gaps of the mesh-like copper foil. Signals only require extremely short traces to enter the interior at the bottom layer, allowing the bottom mesh-like copper foil to maintain its continuity and integrity to the greatest extent possible, continuing to perform its functions of high-frequency grounding and shielding.

[0018] In one alternative embodiment, the radius of the via is 0.1 mm to 1 mm.

[0019] In one alternative embodiment, the underlying mesh-like copper foil is adapted to cover the LED light-emitting device pads around them and maintain a safety distance of at least 3 mil from the LED light-emitting device pads.

[0020] A 3mil safety distance provides sufficient physical buffer space for the flow and spread of molten solder paste. Without this distance, molten solder paste can easily connect to the pads and adjacent grid copper, causing the LED pins to short-circuit with GND and rendering the device inoperable.

[0021] In one alternative embodiment, the bottom layer has pads on which the conductive element is connected. Attached Figure Description

[0022] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of an LED panel shielding structure with safety protection function according to an embodiment of the present invention.

[0024] Explanation of reference numerals in the attached figures: 1. Via; 2. Mesh copper foil. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0026] With the widespread application of LED technology in commercial displays, outdoor displays, and dome screen designs, electromagnetic interference (EMI) issues are becoming increasingly prominent. Electromagnetic radiation generated by high-frequency drive circuits not only affects the normal operation of surrounding electronic equipment but can also cause problems such as color distortion and unstable signal transmission in LED displays, and in severe cases, even trigger system-level electromagnetic compatibility failures.

[0027] Currently, some technologies use metal shielding covers to cover drive circuits or sensitive components, physically isolating and blocking electromagnetic radiation. These solutions rely on mechanical clips or screws to fix the shielding cover to the PCB. While this can improve shielding effectiveness in the short term, long-term use can lead to deformation of the shielding cover due to mechanical stress. Oxidation or dust accumulation at the joint surfaces can create micro-gaps, allowing high-frequency electromagnetic waves to leak through these gaps. Furthermore, repeated disassembly and reassembly of the shielding cover during equipment maintenance accelerates fatigue of the clip structure, ultimately resulting in a significant increase in the contact impedance between the shielding body and the PCB, and a gradual decrease in shielding effectiveness.

[0028] Other technologies enhance shielding by laminating metal foil (such as copper or aluminum) or coating the PCB surface with conductive coatings (such as silver paste or carbon nanotubes). Although the metal layer can reflect some electromagnetic waves, the difference in thermal expansion coefficients between it and the PCB substrate can cause stress cracks at the interface during high and low temperature cycling, forming hidden electromagnetic leakage channels. More seriously, the additional metal layer significantly increases the weight of the PCB (especially in large-size displays) and requires additional etching or spraying processes, leading to increased production costs.

[0029] In addition, some designs attempt to optimize the distribution of wiring layers to reduce radiation, but the surface fine-line circuits will still form an equivalent antenna effect at high frequencies, making it difficult to completely eliminate interference.

[0030] The following is combined Figure 1 The following describes embodiments of the present invention.

[0031] According to an embodiment of this utility model, an LED panel shielding structure with safety protection function is provided, including a top layer and a bottom layer, an internal signal layer, multiple through holes 1 penetrating each layer, and a peripheral shielding structure. The top layer is a continuous copper grounding layer, and the internal signal layer is buried between the top layer and the bottom layer. The peripheral shielding structure is composed of a ground wire and an array of through holes 1 connecting the layers, arranged around the top layer and the outer ring of the internal signal layer. The bottom layer surface is covered with a grid-like copper sheet 2, and LED light-emitting devices are embedded in the grid. The grid-like copper sheet 2 and the LED light-emitting devices together form the bottom shielding layer.

[0032] This LED panel shielding structure with safety protection features employs at least four circuit board layers. The outermost layer is the top layer (component layer), the innermost layer is the bottom layer (lamp surface layer), and at least one internal signal layer is in between. The top layer uses a complete copper foil etching process, retaining a large area of ​​copper skin, with only pads and clearance holes for component soldering exposed. This copper skin is connected to EGND through numerous vias 1, forming a continuous grounding shielding layer. The bottom layer is laid with a grid-like copper skin 2. For example, this grid can be composed of copper wires with a width of 0.2mm, and the grid opening size is 2mm x 2mm to ensure light transmission. This grid-like copper skin 2 is also connected to EGND. The internal signal layer is located between the top and bottom layers and is used to route all signal traces and power lines. The vias 1 are laser-drilled blind vias with a diameter of 0.1mm. These vias 1 are densely arranged around the chips, along the board edges, and in areas requiring shielding, connecting the ground plane of the top layer, the internal signal layer, and the bottom grid to form a three-dimensional low-impedance grounding network.

[0033] Specifically, all signal lines leading from the top-level chip are routed through via 1 into the internal signal layer within 1mm of the chip pins, minimizing the length of exposed traces on the top layer.

[0034] Specifically, the peripheral shielding structure includes drawing a closed ground line with a width of 1mm on the top layer of the PCB and the outer ring of all internal signal layers, using an array of vias with a spacing of 0.3mm to penetrate all board layers along the central axis of the ground line, connecting these ground lines distributed on different layers to form a shielding wall that wraps around the entire edge of the PCB board, and using metallized half-holes or special grounding pads as conductive elements at the corners of the PCB board or specific locations, and reliably connecting this shielding wall to the metal casing of the product by screws or conductive foam.

[0035] LED light-emitting devices (such as LED beads) are located on the bottom layer. The grid-like copper foil 2 around its pads maintains a safe distance from the pads to prevent short circuits during soldering.

[0036] This LED panel shielding structure, featuring safety protection, forms a fully enclosed shielding cavity (Faraday cage) on the top, bottom, and sides. The continuous copper layer on the top and the grid copper layer on the bottom provide face-to-face shielding, while the surrounding via walls effectively suppress electromagnetic energy leakage from the board edges. This structure confines most of the electromagnetic radiation generated by the LED display under high-frequency operation within the cavity, significantly reducing external electromagnetic emissions (EMI). The bottom layer uses a grid copper layer instead of a solid copper layer, balancing shielding and light transmission. The openings between the grids allow LED light to pass through smoothly, avoiding the obstruction of light by a solid copper layer and ensuring the brightness and uniformity of the display. Simultaneously, the grid copper layer still provides good high-frequency grounding and shielding.

[0037] In one embodiment, all signal lines from the top layer are led out of the chip and then pass through via 1 into the internal signal layer.

[0038] After the signal line is led out from the chip, it immediately passes through via 1 and enters the inner layer, leaving only a continuous copper ground layer and chip pads on the top layer. This increases the copper coverage and prevents exposed traces from disrupting the continuity of the top layer shielding, thus enhancing the reflection capability of high-frequency electromagnetic waves. Furthermore, the absence of long-term exposed signal lines on the top layer completely eliminates the equivalent antenna effect of surface traces at high frequencies.

[0039] In one embodiment, the ground line width of the peripheral shielding structure is less than or equal to half the pixel pitch, and the vias 1 are arranged in an array along the edge with a spacing of less than 1 mm between adjacent vias.

[0040] The ground wire width is determined based on the pixel pitch of the LED display (i.e., the center-to-center distance between adjacent LED light-emitting devices), and is controlled to be ≤ half the pixel pitch. For example, when the pixel pitch of the display is 4mm, the peripheral ground wire width is set to 2mm; when the pixel pitch is 2mm, the ground wire width is set to 1mm, ensuring that the ground wire layout does not encroach on the installation space of the LED devices, while adapting to the structural constraints of different sized displays. Vias 1 are laser-drilled vias, arranged in an array along the peripheral edge of the PCB. The spacing between adjacent vias 1 is set to 0.3mm, and vias 1 are electrically connected to the peripheral ground wire, forming a closed via array. The peripheral ground wires of the top layer, internal signal layer, and bottom layer achieve interlayer electrical connection through the above via array, forming a continuous peripheral shielding wall. The top layer ground wire of the shielding wall and the edge portion of the bottom layer mesh copper foil 2 extend together to the edge of the PCB board, connecting with the external metal enclosure, ensuring that the peripheral shielding structure is integrated with the external grounding system.

[0041] In one embodiment, the LED panel shielding structure with safety protection function is box-shaped, and this PCB electromagnetic shielding structure is electrically connected to the metal housing shell through conductive components.

[0042] One implementation of the conductive component involves providing metallized through-holes as mounting holes at the four corners and the middle of the long side of the PCB. The PCB is then secured to the metal housing using copper pillars or metal screws with star-tooth washers. The screw torque ensures a stable, low-impedance electrical contact between the PCB ground plane and the housing.

[0043] Alternatively, grounding pads with silver paste or deposited metal can be printed on the corresponding positions along the edge of the PCB. During assembly, a conductive foam or conductive cloth is pressed between the PCB and the housing, utilizing its elasticity and conductivity to achieve both physical and electrical connections.

[0044] In one embodiment, a metallized hole is provided on the bottom surface, and the LED tube is electrically connected to the internal signal layer through the metallized hole.

[0045] Metallized vias provide a robust, electroplated metal connection that is far more reliable than jumpers or other connection methods. They establish the shortest and most direct electrical path between the LED and the internal driver circuitry, reducing connection impedance and the risk of introducing interference.

[0046] Through precise layout design, the connection points (metallized vias) are integrated into the gaps of the mesh copper foil 2. Signals only require extremely short traces to enter the interior at the bottom layer, allowing the mesh copper foil 2 to maintain its continuity and integrity to the greatest extent possible, and continue to perform its functions of high-frequency grounding and shielding.

[0047] In one embodiment, the radius of via 1 is 0.1mm-1mm.

[0048] In one embodiment, the underlying mesh-like copper foil is adapted to cover the LED light-emitting device pads and maintain a safety distance of at least 3 mil from the LED light-emitting device pads.

[0049] A 3mil safety distance provides sufficient physical buffer space for the flow and spread of molten solder paste. Without this distance, molten solder paste can easily connect to the pads and adjacent grid copper, causing the LED pins to short-circuit with GND and rendering the device inoperable.

[0050] In one embodiment, the surfaces of the top and bottom copper grounding layers are coated with an anti-oxidation conductive coating, and the surface resistance of the top and bottom layers is ≤0.1Ω / sq.

[0051] Although embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A shielding structure for an LED panel with safety protection function, characterized in that, include: Top layer and bottom layer, wherein the top layer is a continuous copper grounding layer; An internal signal layer is embedded between the top layer and the bottom layer; Multiple through-holes penetrating each layer (1); The peripheral shielding structure is composed of the ground wire and the via (1) array of interlayer connections set on the outer ring of the top layer and the inner signal layer; The bottom surface is covered with a grid-shaped copper sheet (2), and LED light-emitting devices are embedded in the grid. The grid-shaped copper sheet (2) and the LED light-emitting devices together form the bottom shielding layer.

2. The LED panel shielding structure with safety protection function according to claim 1, characterized in that, All signal lines of the top layer are led out from the chip and then transferred to the internal signal layer through the via (1).

3. The LED panel shielding structure with safety protection function according to claim 1, characterized in that, The ground wire width of the peripheral shielding structure is less than or equal to half the pixel pitch, and the vias (1) are arranged in an array along the edge with a spacing of less than 1 mm between adjacent vias.

4. The LED panel shielding structure with safety protection function according to claim 3, characterized in that, The PCB electromagnetic shielding structure is box-shaped, and this PCB electromagnetic shielding structure is electrically connected to the metal box shell through conductive components.

5. The LED panel shielding structure with safety protection function according to any one of claims 1-4, characterized in that, The bottom surface is provided with metallized holes; It also includes LED tubes, which are electrically connected to the internal signal layer through the metallized holes.

6. The LED panel shielding structure with safety protection function according to any one of claims 1-4, characterized in that, The radius of the via (1) is 0.1mm-1mm.

7. The LED panel shielding structure with safety protection function according to any one of claims 1-4, characterized in that, The underlying mesh copper foil (2) is adapted to cover the LED light-emitting device pads around the LED light-emitting device pads and maintain a safe distance of at least 3 mil from the LED light-emitting device pads.

8. The LED panel shielding structure with safety protection function according to claim 4, characterized in that, The bottom layer has pads on which the conductive components are connected.

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