A circuit board for double-sided small-pitch LED displays and its fabrication method

Abstract

This application discloses a circuit board for a double-sided small-pitch LED display and its fabrication method. The fabrication method includes: symmetrically arranging a high thermal conductivity composite substrate on both sides; transferring and etching patterns on both sides of the high thermal conductivity composite substrate, transferring circuit patterns and pads to both sides of the high thermal conductivity composite substrate through exposure and development; drilling heat dissipation channels and through-holes in the high thermal conductivity composite substrate; filling the heat dissipation channels with thermally conductive filler and the through-holes with conductive filler; placing thermally conductive pads between the pads and the heat dissipation channels; and mounting display units on the pads. This application provides heat dissipation channels in the high thermal conductivity composite substrate and thermally conductive pads between the heat dissipation channels and the pads, ensuring that the heat generated by the display units in the pads can be dissipated in a timely manner through the thermally conductive pads and heat dissipation channels, thereby reducing faults such as solder joint detachment and extending the service life of the double-sided small-pitch LED display.

Description

Technical Field

[0001] This invention relates to the technical field of double-sided small-pitch LED displays, and more particularly to a circuit board for double-sided small-pitch LED displays and its manufacturing method. Background Technology

[0002] With the upgrading of display technology, small-pitch LED displays are widely used in many fields due to their advantages such as high resolution and high brightness, and are rapidly developing towards micro-pitch and high density. Double-sided circuit boards have become the mainstream choice for mid-to-high-end products because they can increase circuit density and reduce substrate size. As a core component, the circuit board plays a crucial role in physical support and signal transmission, and its quality directly determines the performance and lifespan of the display. Currently, most existing double-sided small-pitch LED circuit boards use traditional substrates and manufacturing processes. Although they can meet basic requirements, they are no longer suitable for the industry's upgrading requirements and have many core problems.

[0003] First, the inconsistent performance of double-sided circuit boards is poor, with significant differences in electrical and heat dissipation performance between the front and back, affecting the uniformity of double-sided displays. Second, double-sided small-pitch LED displays have a higher component density, generating more heat than single-sided LED displays. Existing circuit boards lack sufficient heat dissipation performance to meet the heat dissipation requirements of high-density components on both sides. If the display operates at high temperatures for extended periods, it will accelerate product aging. In summary, existing circuit boards and their manufacturing methods have many shortcomings and cannot meet the needs of industry development, necessitating the development of new technologies to solve these problems. Summary of the Invention

[0004] This invention aims to at least partially solve one of the problems in related technologies. Therefore, one objective of this invention is to provide a method for manufacturing a circuit board for a double-sided small-pitch LED display screen. A heat dissipation channel is provided in a high thermal conductivity composite substrate, and a thermally conductive pad is placed between the heat dissipation channel and the solder pads. This ensures that the heat generated by the display unit in the solder pads can be dissipated in a timely manner through the thermally conductive pad and the heat dissipation channel, thereby reducing faults such as solder joint detachment and extending the service life of the double-sided small-pitch LED display screen.

[0005] A method for fabricating a circuit board for a double-sided small-pitch LED display screen includes: A double-sided symmetrical layout is adopted for the high thermal conductivity composite substrate; Pattern transfer and etching are performed on both sides of the high thermal conductivity composite substrate. The circuit pattern and pads are transferred to both sides of the high thermal conductivity composite substrate by exposure and development. Heat dissipation channels and through holes are drilled in the high thermal conductivity composite substrate; thermally conductive filler is filled in the heat dissipation channels, and conductive filler is filled in the through holes. A thermally conductive pad is placed between the solder pad and the heat dissipation channel; Install the display unit on the pads.

[0006] Furthermore, the thermally conductive filler is an insulating material, and the thermally conductive filler is filled into the heat dissipation channel by dispensing adhesive.

[0007] Furthermore, both the thermally conductive filler and the electrically conductive filler are copper pillars, and the heat dissipation channel and the through hole are simultaneously electroplated and filled by pulse electroplating; the heat dissipation channel is not connected to the through hole and the circuit pattern.

[0008] Furthermore, the via is located on the side edge of the high thermal conductivity composite substrate, and is used to realize the side trace of the high thermal conductivity composite substrate.

[0009] Furthermore, a thermally conductive pad is provided between the pad and the heat dissipation channel, specifically including: forming a pad groove by laser etching between the pad and the heat dissipation channel, filling the pad groove with a thermally conductive layer to form a thermally conductive pad for connecting the pad and the heat dissipation channel.

[0010] Furthermore, the thermally conductive layer is thermally conductive silicone grease, which is applied to the groove of the pad.

[0011] Furthermore, it also includes: coating the surface of the high thermal conductivity composite substrate with a modified solder resist layer that is moisture-resistant and corrosion-resistant, wherein the modified solder resist layer is a fluorine-modified acrylate solder resist layer, an epoxy-modified phenolic resin solder resist layer, or a silane coupling agent-modified epoxy solder resist layer.

[0012] Furthermore, before installing the display unit, the process includes: printing solder paste onto the pads using a stencil; and performing reflow soldering after installing the display unit.

[0013] Furthermore, the display unit includes LED beads and a driver IC, and the display units are distributed in an array on the circuit board.

[0014] The second objective of this application is to provide a circuit board for a double-sided small-pitch LED display screen, which is prepared based on the above-described method for preparing a circuit board for a double-sided small-pitch LED display screen.

[0015] The technical solutions provided in this application have the following advantages compared with the prior art: This application provides a method for fabricating a circuit board for a double-sided small-pitch LED display. A high thermal conductivity composite substrate is selected as the substrate for the circuit board, which balances the thermal conductivity and mechanical strength of the circuit board. Simultaneously, the high thermal conductivity composite substrate is arranged in a double-sided symmetrical layout, ensuring that the pad positions, circuit patterns, vias, heat dissipation channels, and other components on both sides of the high thermal conductivity composite substrate are symmetrically distributed, and that the fabrication process and control parameters are consistent. This eliminates differences in electrical and heat dissipation performance between the front and back sides, ensuring the uniformity of the double-sided display effect and improving the product experience. This application also includes heat dissipation channels in the high thermal conductivity composite substrate and thermally conductive pads between the heat dissipation channels and the pads, ensuring that the heat generated by the display units in the pads can be dissipated in a timely manner through the thermally conductive pads and heat dissipation channels, thereby reducing faults such as solder joint detachment and extending the service life of the double-sided small-pitch LED display.

[0016] This application provides a circuit board for a double-sided small-pitch LED display screen, which can achieve uniform performance on both sides of the circuit board. Through symmetrical layout and unified parameter control, it eliminates the differences in electrical and heat dissipation performance between the front and back sides, ensures the uniformity of the double-sided display effect, and improves the product experience. Through the combined design of high thermal conductivity composite substrate, heat dissipation channel and thermal pad, the heat generated by the components is quickly dissipated, reducing faults such as solder joint detachment and extending the service life of the double-sided small-pitch LED display screen. Attached Figure Description

[0017] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] In the attached image: Figure 1 This is a schematic flowchart of the preparation method in Example 2 of this application; Figure 2 This is a schematic diagram showing the positions of the thermal pads, heat dissipation channels, and solder pads in the circuit board of Embodiment 3 of this application.

[0020] Reference numerals: 11. High thermal conductivity composite substrate; 12. Pad; 13. Heat dissipation channel; 14. Thermal pad. Detailed Implementation

[0021] To provide a clearer understanding of the technical features, objectives, and effects of this invention, specific embodiments are now described in detail with reference to the accompanying drawings. In the following description, it should be understood that the orientations or positional relationships indicated by terms such as "front," "rear," "upper," "lower," "left," "right," "longitudinal," "horizontal," "vertical," "horizontal," "top," "bottom," "inner," "outer," "head," and "tail" are based on the orientations or positional relationships shown in the accompanying drawings, and are constructed and operated in a specific orientation. They are only for the convenience of describing this technical solution and do not indicate that the referred mechanism or element must have a specific orientation; therefore, they should not be construed as limitations on this invention.

[0022] It should also be noted that, unless otherwise explicitly specified and limited, terms such as "installation," "connection," "linking," "fixing," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. When an component is referred to as being "on" or "below" another component, the component can be located "directly" or "indirectly" on the other component, or there may be one or more intermediary components. The terms "first," "second," "third," etc., are only for the convenience of describing this technical solution and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, features defined with "first," "second," "third," etc., may explicitly or implicitly include one or more of that feature. For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances.

[0023] In the following description, specific details such as particular system structures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the invention. However, those skilled in the art will understand that the invention can be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, mechanisms, circuits, and methods are omitted so as not to obscure the description of the invention with unnecessary detail.

[0024] Example 1

[0025] This application provides a method for fabricating a circuit board for a double-sided small-pitch LED display screen, comprising: The high thermal conductivity composite substrate 11 is arranged in a double-sided symmetrical layout. Pattern transfer and etching are performed on both sides of the high thermal conductivity composite substrate 11, and the circuit pattern and pads 12 are transferred to both sides of the high thermal conductivity composite substrate 11 by exposure and development. Heat dissipation channels 13 and through holes are drilled in the high thermal conductivity composite substrate 11; thermally conductive filler is filled in the heat dissipation channels 13 and conductive filler is filled in the through holes. A thermally conductive pad 14 is provided between the pad 12 and the heat dissipation channel 13; Install the display unit on pad 12.

[0026] This application selects a high thermal conductivity composite substrate 11 as the substrate of the circuit board, which can take into account both the thermal conductivity and mechanical strength of the circuit board. At the same time, the high thermal conductivity composite substrate 11 is arranged in a double-sided symmetrical layout to ensure that the positions of the pads 12, circuit patterns, vias, heat dissipation channels 13 and other components on both sides of the high thermal conductivity composite substrate 11 are symmetrically distributed, and the manufacturing process and control parameters are consistent, eliminating the differences in electrical and heat dissipation performance between the front and back sides, ensuring the uniformity of the double-sided display effect, and improving the product experience.

[0027] This application provides a heat dissipation channel 13 in the high thermal conductivity composite substrate 11, and a thermally conductive pad 14 between the heat dissipation channel 13 and the pad 12, to ensure that the heat generated by the display unit in the pad 12 can be dissipated in time through the thermally conductive pad 14 and the heat dissipation channel 13, thereby reducing failures such as solder joint detachment and extending the service life of the double-sided small-pitch LED display.

[0028] This application provides a circuit board for a double-sided small-pitch LED display screen, including a high thermal conductivity composite substrate 11, pads 12 located in the high thermal conductivity composite substrate 11, circuit patterns, vias, heat dissipation channels 13, a thermal pad, and a display unit. The heat dissipation channels 13 and the vias are holes penetrating both sides of the high thermal conductivity composite substrate 11, and are respectively filled with thermally conductive filler and electrically conductive filler. The heat dissipation channels 13 are used to dissipate heat from components on both sides of the circuit board, and the vias are used to connect the components on both sides of the circuit board. The thermal pad is fixed to the front and back sides of the high thermal conductivity composite substrate 11 and connects the heat dissipation channels 13 and the pads 12. In this application, the pads 12, circuit patterns, thermal pad, and display unit are symmetrically arranged on both sides of the high thermal conductivity composite substrate 11.

[0029] This application provides a circuit board for a double-sided small-pitch LED display screen, which can achieve uniform performance on both sides of the circuit board. Through symmetrical layout and unified parameter control, it eliminates the differences in electrical and heat dissipation performance between the front and back sides, ensures the uniformity of double-sided display effect, and improves product experience. Through the coordinated design of high thermal conductivity composite substrate 11, heat dissipation channel 13 and thermal pad 14, the heat generated by the components is quickly dissipated, reducing faults such as solder joint detachment and extending the service life of the double-sided small-pitch LED display screen.

[0030] Example 2

[0031] like Figure 1As shown, this application provides a method for fabricating a circuit board for a double-sided small-pitch LED display screen; including: S1: A double-sided symmetrical circuit layout is performed on the high thermal conductivity composite substrate 11; multiple high thermal conductivity composite substrates 11 are spliced ​​together to form a display screen. This application only describes one high thermal conductivity composite substrate 11 in detail. In the high thermal conductivity composite substrate 11, the circuit patterns and pad 12 positions on the front and back sides are completely symmetrically arranged to ensure that the double-sided process parameters and finished products of the high thermal conductivity composite substrate 11 are consistent. It is necessary to ensure that the size and spacing of the circuits and pads 12 on the front and back sides are completely consistent.

[0032] The thermal conductivity of the high thermal conductivity composite substrate 11 in this application is ≥15W / (m·K), and it can be made of thermally conductive carbon fiber composite material, diamond / copper composite material, highly filled thermally conductive plastic and graphene-based composite material, etc.

[0033] S2: Pattern transfer and etching. The circuit pattern and pads 12 are transferred to both sides of the high thermal conductivity composite substrate 11 through exposure and development. Then, excess copper foil is removed by chemical etching to form pads 12 and circuit patterns.

[0034] Specifically, this application can be made using dry etching at 40-50℃ for 10-15 minutes. After removing the film and rinsing, the accuracy of the circuit is checked to ensure that the line width and spacing are controlled within 40-60μm and the size deviation of pad 12 is ≤±5μm.

[0035] If the line width, line spacing, and pad 12 size deviations are greater than the above values, the line width, line spacing, and pad 12 size will be corrected by laser etching. If they cannot be corrected, the substrate will be reworked or scrapped.

[0036] S3: Heat dissipation channels 13 and through holes are drilled in the high thermal conductivity composite substrate 11. The heat dissipation channels penetrate the high thermal conductivity composite substrate 11. The positions of the heat dissipation channels can correspond one-to-one with the positions of the pads 12 and are located on the side of the pads 12 or between two pads 12. Two pads 12 correspond to one heat dissipation channel 13, or multiple pads 12 correspond to one heat dissipation channel 13. The function of the heat dissipation channel 13 is to quickly dissipate the heat generated by the display unit in the pads 12 to improve the heat dissipation performance of the circuit board. The size of the heat dissipation channel 13 needs to be determined according to factors such as the spacing between the pads 12 in the circuit board to ensure that the size of the heat dissipation channel 13 does not affect the routing of the pads 12 and the circuit pattern, and also does not affect the mechanical strength of the circuit board.

[0037] The vias are located on the edge side of the circuit board to enable edge routing and seamless splicing. In this application, the routing structure is located on the side of the circuit board, reducing splicing gaps. Side routing arranges signal and power lines perpendicularly along the side of the substrate, connecting adjacent modules via side pins. This allows the front display area to extend to the edge, and the splicing gap can be controlled to ≤20 micrometers, far below the human eye's perception limit.

[0038] In this application, the through-hole and the heat dissipation channel 13 can be formed simultaneously during the drilling process. If their dimensions are the same, the through-hole and the heat dissipation channel 13 can be generated simultaneously through a single control program. If their dimensions are different, the heat dissipation channel 13 and the heat-conducting through-hole are drilled separately in two steps. In actual operation, in order to improve drilling efficiency, the dimensions of the heat dissipation channel 13 and the heat-conducting through-hole can be set to be the same.

[0039] S4: Fill the heat dissipation channel 13 with thermally conductive filler and fill the through hole with porous conductive filler.

[0040] The conductive filler in this application can be a copper pillar formed by electroplating copper, etc., used to achieve electrical connection between the front and back sides of the high thermal conductivity composite substrate 11.

[0041] In this application, the thermally conductive filler needs to have high thermal conductivity. As one embodiment, the thermally conductive filler is an insulating material with good thermal conductivity, and is filled into the heat dissipation channel 13 by dispensing. The thermally conductive filler can be, for example, a silicon carbide infrared radiation coating.

[0042] In another embodiment, the thermally conductive filler can also be a copper pillar. In this case, it is necessary to ensure that the heat dissipation channel 13 is not connected to the via and the circuit pattern. That is, the copper pillar in the heat dissipation channel 13 only serves as a heat dissipation medium and will not have electrical connection with the circuit pattern, pad 12, or via, thus avoiding interference with the normal signal transmission of the circuit board. This application uses the same material for both the thermally conductive and conductive fillers, allowing for simultaneous copper plating of the heat dissipation channel 13 and vias, improving manufacturing efficiency. Specifically, this application uses pulse electroplating technology to form copper pillars located within the heat dissipation channel 13 and vias. Pulse electroplating improves filling efficiency, avoids filling depressions, eliminates the need for rework, and increases filling efficiency.

[0043] S5: A thermal pad 14 is placed between the pad 12 and the heat dissipation channel 13.

[0044] Specifically, a pad groove is formed between the pad 12 and the heat dissipation channel 13 by laser etching. A thermally conductive layer is filled into the pad groove to form a thermally conductive pad 14 for connecting the pad 12 and the heat dissipation channel 13. The heat dissipation channel 13 and the thermally conductive pad 14 cooperate to form an all-round heat dissipation system in the circuit board. In this application, the pad groove is used to limit the position of the thermally conductive pad 14.

[0045] As a specific embodiment, the thermally conductive layer in this application is thermally conductive silicone grease, which is applied into the groove of the pad. The thermally conductive silicone grease can efficiently conduct heat between the pad 12 and the heat dissipation channel 13, while also avoiding the risk of short circuit.

[0046] S6: A modified solder resist layer that is moisture-resistant and corrosion-resistant is coated on the surface of the high thermal conductivity composite substrate 11. The modified solder resist layer is a fluorine-modified acrylate solder resist layer, an epoxy-modified phenolic resin solder resist layer, or a silane coupling agent-modified epoxy solder resist layer.

[0047] This step utilizes a precise coating process to ensure uniform thickness of the modified solder resist layer on both sides of the circuit board, eliminating pinholes and peeling issues. The presence of the modified solder resist layer in this application avoids the need for subsequent conformal coating of the circuit board, thus improving manufacturing efficiency through process optimization.

[0048] S7: Use a stencil to precisely print solder paste onto pad 12, with the thickness controlled at 100-150μm, to ensure the quality of subsequent soldering.

[0049] S8: Install the display unit; the display unit includes LED beads and a driver IC, and the driver IC is connected to the pins of the LED beads through copper foil leads; the display units are arranged in an array on the circuit board, and the distribution position and size of the display units on both sides of the circuit board are completely consistent.

[0050] S9: Reflow soldering, which involves heating the solder paste in a reflow oven to melt and wet the pads 12, and then cooling it to form a strong electrical connection.

[0051] This application establishes a unified control system for process parameters on both sides of the circuit board. During the double-sided processing of the circuit board, the processes and control parameters for circuit patterns, pads 12, heat dissipation channels 13, heat conduction holes, and heat conduction pads 14 are all ensured to be consistent, thus ensuring the consistency of performance on both sides of the circuit board. Through symmetrical layout and precise parameter control, the differences in electrical and heat dissipation performance between the front and back sides are eliminated, ensuring the uniformity of double-sided display effects and improving the product experience.

[0052] Meanwhile, this application provides a heat dissipation channel 13 in the high thermal conductivity composite substrate 11 and a thermally conductive pad 14 between the heat dissipation channel 13 and the pad 12 to ensure that the heat generated by the display unit in the pad 12 can be dissipated in time through the thermally conductive pad 14 and the heat dissipation channel 13, thereby reducing failures such as solder joint detachment and extending the service life of the double-sided small-pitch LED display.

[0053] This application simplifies the manufacturing process, improves production efficiency and product yield, reduces overall production costs, enables large-scale and efficient production, and enhances product market competitiveness. The overall technical solution is highly compatible, adaptable to various packaging processes such as COB and SMD, and suitable for double-sided small-pitch LED displays of different specifications, making it widely applicable.

[0054] This application enhances the moisture and corrosion resistance and the mechanical strength of the substrate, making it suitable for complex application scenarios such as outdoor and humid environments. At the same time, through the optimization of the side wiring structure, it achieves seamless splicing on both sides, expanding the application range of the product.

[0055] Example 3

[0056] This application provides a circuit board for a double-sided small-pitch LED display screen, including a high thermal conductivity composite substrate 11, pads 12 located on both sides of the high thermal conductivity composite substrate 11, circuit patterns, vias, heat dissipation channels 13, thermal pads, and display units; wherein, the heat dissipation channels 13 and the vias are holes penetrating both sides of the high thermal conductivity composite substrate 11, and their interiors are filled with thermally conductive filler and conductive filler, respectively; the heat dissipation channels 13 are used to dissipate heat from the components on both sides of the circuit board, and the vias are used to connect the components on both sides of the circuit board.

[0057] In this embodiment, the dimensions of the heat dissipation channel 13 and the via are set to be the same, and both the thermally conductive filler and the conductive filler are made of copper. This allows the via and the heat dissipation channel 13 to be formed simultaneously during the drilling process, and the thermally conductive filler and conductive filler to be filled simultaneously using pulse electroplating technology. Simultaneously, it is necessary to ensure that the heat dissipation channel 13 is not connected to the via and the circuit pattern; that is, the copper pillars in the heat dissipation channel 13 only serve as a heat dissipation medium and do not form electrical connections with the circuit pattern, pads 12, or vias, thus avoiding interference with the normal signal transmission of the circuit board.

[0058] In this application, the vias are located on the side edge of the circuit board to achieve edge routing and seamless splicing. The routing structure of the circuit board in this application is set on the side, reducing splicing gaps. Side routing vertically arranges signal and power lines along the side of the substrate, connecting adjacent modules through side pins, allowing the front display area to extend to the edge. The splicing gap can be controlled to ≤20 micrometers, far below the human eye's perception limit. Seamless splicing of side routing enables high utilization of the spliced ​​display screen, closer spacing between display units between pads 12, and better overall screen integration.

[0059] like Figure 2 As shown, a thermal pad is located between the pads 12 and the heat dissipation channel 13. Specifically, in this embodiment, four rows and four columns of pads 12 are arranged on the front and back sides of the high thermal conductivity composite substrate 11. A heat dissipation channel 13 is arranged between two adjacent pads 12, and a thermal pad 14 is arranged between the heat dissipation channel 13 and the pads 12. The heat generated by the LED beads in the pads 12 during operation can be transferred to the heat dissipation channel 13 through the thermal pad 14 and dissipated in time. Through the planar thermal pad 14 and the vertical heat dissipation channel 13, a three-dimensional heat dissipation network is formed, improving the heat dissipation performance of the circuit board.

[0060] In this application, the pads 12, circuit patterns, thermal pads, and display units are symmetrically arranged on both sides of the high thermal conductivity composite substrate 11; and the manufacturing process and control parameters are completely consistent. Through symmetrical layout and precise parameter control, the differences in electrical and heat dissipation performance between the front and back sides are eliminated, ensuring the uniformity of the double-sided display effect and improving the product experience.

[0061] It is understood that the above embodiments only illustrate preferred embodiments of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can freely combine the above technical features without departing from the concept of the present invention, and can also make several modifications and improvements, all of which fall within the protection scope of the present invention. Therefore, all equivalent transformations and modifications made with respect to the scope of the claims of the present invention should fall within the scope of the claims of the present invention.

Claims

1. A method for manufacturing a circuit board for a double-sided small-pitch LED display screen, characterized in that, include: A double-sided symmetrical layout is adopted for the high thermal conductivity composite substrate; Pattern transfer and etching are performed on both sides of the high thermal conductivity composite substrate. The circuit pattern and pads are transferred to both sides of the high thermal conductivity composite substrate by exposure and development. Heat dissipation channels and through holes are drilled in the high thermal conductivity composite substrate; The heat dissipation channel is filled with thermally conductive filler, and the through hole is filled with porous conductive filler. A thermally conductive pad is placed between the solder pad and the heat dissipation channel; Install the display unit on the pads.

2. The method for manufacturing a circuit board for a double-sided small-pitch LED display screen according to claim 1, characterized in that, The thermally conductive filler is made of insulating material and is filled into the heat dissipation channel by dispensing adhesive.

3. The method for manufacturing a circuit board for a double-sided small-pitch LED display screen according to claim 1, characterized in that, Both the thermally conductive filler and the electrically conductive filler are copper pillars, and the heat dissipation channel and the through hole are simultaneously electroplated and filled by pulse electroplating; the heat dissipation channel is not connected to the through hole and the circuit pattern.

4. The method for manufacturing a circuit board for a double-sided small-pitch LED display screen according to claim 1, characterized in that, The via is located on the side edge of the high thermal conductivity composite substrate and is used to realize the side routing of the high thermal conductivity composite substrate.

5. A method for manufacturing a circuit board for a double-sided small-pitch LED display screen according to claim 1, characterized in that, The thermal pad is provided between the pad and the heat dissipation channel, specifically by: forming a pad groove by laser etching between the pad and the heat dissipation channel, filling the pad groove with a thermally conductive layer to form a thermally conductive pad for connecting the pad and the heat dissipation channel.

6. A method for manufacturing a circuit board for a double-sided small-pitch LED display screen according to claim 5, characterized in that, The thermally conductive layer is thermally conductive silicone grease, which is applied to the groove of the pad.

7. A method for manufacturing a circuit board for a double-sided small-pitch LED display screen according to claim 1, characterized in that, Also includes: A modified solder resist layer that is moisture-resistant and corrosion-resistant is coated on the surface of the high thermal conductivity composite substrate. The modified solder resist layer is a fluorine-modified acrylate solder resist layer, an epoxy-modified phenolic resin solder resist layer, or a silane coupling agent-modified epoxy solder resist layer.

8. A method for manufacturing a circuit board for a double-sided small-pitch LED display screen according to claim 1, characterized in that, Before installing the display unit, the process includes: printing solder paste onto the pads using a stencil; and performing reflow soldering after installing the display unit.

9. A method for manufacturing a circuit board for a double-sided small-pitch LED display screen according to claim 1, characterized in that, The display unit includes LED beads and a driver IC, and the display units are arranged in an array on the circuit board.

10. A circuit board for a double-sided small-pitch LED display screen, characterized in that, It is prepared based on the method for preparing a circuit board for a double-sided small-pitch LED display screen according to any one of claims 1-9.

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