A single-sided multiplex structure for wireless charging systems

Abstract

This application relates to the field of wireless charging technology and discloses a single-sided reusable structure for a wireless charging system, comprising: a first FPC single-sided panel, a second FPC single-sided panel, and an adhesive layer. The adhesive layer is disposed between the first FPC single-sided panel and the second FPC single-sided panel and connects the first FPC single-sided panel and the second FPC single-sided panel respectively. Both the first and second FPC single-sided panels have a metal wire layer on the side opposite to the adhesive layer. The metal wire layer of the first FPC single-sided panel has a plurality of connection through-holes arranged thereon, and the metal wire layer of the second FPC single-sided panel has connection pads arranged thereon corresponding to the connection through-holes. The connection through-holes are electrically connected to the connection pads. This application improves the economy, reliability, and electrical performance of wireless charging substrates.

Description

Technical Field

[0001] This application relates to the field of wireless charging technology, and specifically to a single-panel multiplex structure for a wireless charging system. Background Technology

[0002] In the field of wireless charging technology, the panel substrate of wireless charging coils often adopts a double-sided panel structure design. Specifically, it uses a single-layer substrate (such as polyimide film) with copper cladding on both sides. During the manufacturing process, complex processes such as chemical etching and electroplating are required to achieve the double-sided conductive layer. This double-sided copper cladding structure requires multiple patterning processes, resulting in low yield and cumbersome process. The thickness of the substrate and the bonding strength of the copper layer are limited by the material properties, making it difficult to further reduce the thickness. On the other hand, excessively thick substrates affect their bending performance. If the panel substrate of the wireless charging coil adopts a single-sided panel structure design, it only has a single layer of wiring, which cannot meet the current density and heat dissipation requirements of medium and high power wireless charging. The inductance (Q value) is limited by the thickness of the single-layer copper, making it difficult to adapt to fast charging standards above 15W. This situation needs to be changed. Utility Model Content

[0003] In view of this, this application provides a single-panel multiplexing structure for a wireless charging system to solve the aforementioned technical problems.

[0004] To achieve the above objectives, the technical solution adopted is as follows:

[0005] A single-panel multiplex structure for a wireless charging system includes:

[0006] A first FPC single-sided panel, a second FPC single-sided panel, and an adhesive layer, wherein the adhesive layer is disposed between the first FPC single-sided panel and the second FPC single-sided panel and connects the first FPC single-sided panel and the second FPC single-sided panel respectively.

[0007] Both the first FPC single-sided panel and the second FPC single-sided panel have a metal line layer on the side away from the adhesive layer. The metal line layer of the first FPC single-sided panel has a plurality of connection through holes arranged thereon, and the metal line layer of the second FPC single-sided panel has connection pads corresponding to the connection through holes arranged thereon. The connection through holes are electrically connected to the connection pads.

[0008] This application further specifies that the first FPC single-sided panel includes a first base film layer, a first metal layer, and a cover film layer stacked sequentially.

[0009] This application further specifies that the second FPC single-sided panel includes a second base film layer and a second metal layer stacked sequentially.

[0010] This application is further configured such that the adhesive layer is bonded and fixed to the first base film layer and the second metal layer respectively.

[0011] This application further specifies that a conductive adhesive or solder layer is filled between the connecting via and the connecting pad to achieve interlayer conductivity of the metal wire layer.

[0012] This application is further configured such that, on the vertical projection of the first FPC single-sided panel or the second FPC single-sided panel, the coverage area of ​​the connecting pad is greater than the coverage area of ​​the connecting via.

[0013] This application further specifies that the adhesive layer has a preset adhesive thickness, which includes 5±0.5um.

[0014] This application further specifies that the first base film layer and the second base film layer have a preset base film thickness, wherein the preset base film thickness includes 12.5±0.5um.

[0015] This application is further configured such that: the first metal layer and the second metal layer have a preset metal thickness, the preset metal thickness including 12±0.5um.

[0016] This application further specifies that the covering film layer has a preset covering thickness, the preset covering thickness including 12.5±0.5um.

[0017] In summary, compared with the prior art, this application discloses a single-sided reusable structure for a wireless charging system. The adhesive layer connects the first FPC single-sided panel and the second FPC single-sided panel respectively. Both the first and second FPC single-sided panels have metal wire layers on the side away from the adhesive layer. The metal wire layer of the first FPC single-sided panel has a plurality of connection through holes arranged thereon, and the metal wire layer of the second FPC single-sided panel has connection pads corresponding to the connection through holes arranged thereon. The connection through holes and the connection pads are electrically connected. That is, through the above configuration, the structural design of single-sided single-layer wiring and double-sided double-sided copper cladding in the related technology is abandoned. The composite structure of the first FPC single-sided panel, the second FPC single-sided panel and the adhesive layer improves the economy, reliability and electrical performance of the wireless charging substrate. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1This is a schematic diagram of the first single-panel reuse structure of this application;

[0020] Figure 2 yes Figure 1 Enlarged view of point A;

[0021] Figure 3 yes Figure 1 Enlarged view of point B;

[0022] Figure 4 This is a schematic diagram of the second single-panel reuse structure of this application. Detailed Implementation

[0023] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0024] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element. Furthermore, components, features, and elements with the same names in different embodiments of this application may have the same meaning or different meanings, the specific meaning of which must be determined by its interpretation in that specific embodiment or further in conjunction with the context of that specific embodiment.

[0025] It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit this application.

[0026] In the following description, the use of suffixes such as "module," "part," or "unit" to denote elements is solely for the purpose of illustrative purposes and has no specific meaning in itself. Therefore, "module," "part," or "unit" may be used interchangeably.

[0027] In the description of this application, it should be noted that the terms "upper," "lower," "left," "right," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0028] The technical solutions shown in this application will be described in detail below through specific embodiments. It should be noted that the order of description of the following embodiments is not intended to limit the priority of the embodiments.

[0029] Please refer to Figures 1 to 4 The single-sided multiplex structure for a wireless charging system according to the present application includes a first FPC single-sided panel 1, a second FPC single-sided panel 2, and an adhesive layer 3. The adhesive layer 3 is disposed between the first FPC single-sided panel 1 and the second FPC single-sided panel 2, and connects the first FPC single-sided panel 1 and the second FPC single-sided panel 2 respectively, thereby forming a single-sided multiplex structure, thus eliminating the structural design of single-sided single-layer wiring and double-sided copper cladding of double-sided panels in the related technology.

[0030] The first FPC single-sided panel 1 and the second FPC single-sided panel 2 are provided with metal wire layers 4 on the side away from the adhesive layer 3. The metal wire layer 4 of the first FPC single-sided panel 1 is provided with a plurality of connection through holes 5, and the metal wire layer 4 of the second FPC single-sided panel 2 is provided with connection pads 6 corresponding to the connection through holes 5. The connection through holes 5 and the connection pads 6 are electrically connected.

[0031] Therefore, the first FPC single-sided panel 1 and the second FPC single-sided panel 2 are both flexible printed circuit boards with good flexibility characteristics. They are firmly bonded together by the adhesive layer 3 to form a single-sided reusable structure, thereby forming an integrated composite structure. At the same time, based on the structural design of the metal line layer 4, the connecting through holes 5 and the connecting pads 6, the first FPC single-sided panel 1 and the second FPC single-sided panel 2 are electrically interconnected, forming a multi-layer conductive path, which improves the overall conductivity and Q value performance.

[0032] On the other hand, by combining the single-sided single-layer wiring of the first FPC single-sided panel 1 and the second FPC single-sided panel 2, the double-sided patterning process of double-sided double-sided copper cladding is not required, which improves the material utilization rate. In one application scenario, low-cost conventional substrates can be used. The preparation of the single-sided reusable structure reduces the overall cost by 20%-30% compared with the single-sided single-layer wiring and double-sided double-sided copper cladding in related technologies. In addition, the production process of the single-sided single-layer wiring composite structure is short, and the lamination process only requires one gluing, reducing the defect risk caused by multiple etching and electroplating of traditional double-sided panels.

[0033] In one embodiment, a single-panel reuse structure is applied to the wireless charging coil of a smart terminal device to achieve the high current density and good heat dissipation performance required for medium-to-high power (e.g., 15W and above) wireless charging, while taking into account both flexible design and structural reliability.

[0034] In the specific implementation process, the first FPC single-sided panel 1 includes a first base film layer 11, a first metal layer 12 and a cover film layer 13 stacked in sequence, and the second FPC single-sided panel 2 includes a second base film layer 21 and a second metal layer 22 stacked in sequence.

[0035] The single-sided reusable structure can be considered as consisting of a second base film layer 21, a second metal layer 22, an adhesive layer 3, a first base film layer 11, a first metal layer 12, and a cover film layer 13 stacked sequentially.

[0036] The adhesive layer 3 is bonded and fixed to the first base film layer 11 and the second metal layer 22 respectively.

[0037] It should be noted that conductive adhesive or solder layer is filled between the connecting through hole 5 and the connecting pad 6 to achieve interlayer conductivity of the metal line layer 4, that is, the upper and lower electrical interconnection of the first FPC single-sided panel 1 and the second FPC single-sided panel 2.

[0038] In the vertical projection of the first FPC single-sided panel 1 or the second FPC single-sided panel 2, the coverage area of ​​the connecting pad 6 is greater than the coverage area of ​​the connecting via 5, thereby ensuring that the connecting pad 6 completely covers the connecting via 5, effectively improving the stability of interlayer electrical connection, enhancing the wetting area between the conductive medium (such as conductive glue or solder) and the pad, reducing the risk of defects such as cold solder joints and bubbles during the soldering process, and further ensuring the reliability and conductivity of the overall structure.

[0039] Furthermore, the connecting via 5 and the connecting pad 6 are electrically connected by conductive adhesive or solder layer, thereby eliminating the electroplating via step required in the traditional manufacturing process. This avoids problems such as defect rate (void or breakage) and uneven metal deposition in electroplated vias, especially in bending scenarios, thereby improving the stability of interlayer connection.

[0040] In the specific implementation process, the adhesive layer 3 has a preset adhesive thickness, which includes 5±0.5um.

[0041] The adhesive layer 3 includes an epoxy resin layer or an acrylic adhesive layer, and the interlayer bonding is achieved through a hot pressing process, that is, bonding and fixing the first FPC single-sided panel 1 and the second FPC single-sided panel 2.

[0042] Preferably, the preset adhesive thickness of the adhesive layer 3 is 5µm, so as to balance the thinness requirement of the overall structure with the adhesive strength, and ensure that the single-panel reusable structure has a relatively thin thickness, which is beneficial to the heat dissipation requirements of medium and high power wireless charging.

[0043] In the specific implementation process, the first base film layer 11 and the second base film layer 21 have a preset base film thickness, which includes 12.5±0.5um.

[0044] Preferably, the preset thickness of the first base film layer 11 and the second base film layer 21 is 12.5 μm, so as to have both sufficient structural support and good bendability, which is conducive to achieving the goal of miniaturization and lightweighting of the wireless charging coil structure.

[0045] In the specific implementation process, the first metal layer 12 and the second metal layer 22 have a preset metal thickness, which includes 12±0.5um.

[0046] Preferably, the preset metal thickness of the first metal layer 12 and the second metal layer 22 is 12um to meet the conductivity requirements, heat dissipation requirements and inductance performance control of the wireless charging coil under medium and high power operating conditions, while taking into account the etching precision control and electrical performance requirements in FPC manufacturing. This effectively improves the current carrying capacity per unit area while ensuring fine wiring.

[0047] It is understood that the first metal layer 12 and the second metal layer 22 are the specific components of the metal wire layer 4 on the side of the first FPC single-sided panel 1 and the second FPC single-sided panel 2 away from the adhesive layer 3, respectively.

[0048] In the specific implementation process, the cover film layer 13 has a preset cover thickness, which includes 12.5±0.5um, to protect the wiring pattern of the first metal layer 12 and improve its oxidation resistance, abrasion resistance and mechanical strength.

[0049] Preferably, the preset coverage thickness of the cover film 13 is 12.5um, so as to balance the flexibility of the overall FPC structure and the mounting reliability. It is particularly suitable for the flexible packaging requirements of high-density wireless charging coils, and is especially suitable for smart terminal devices with limited structural space or requiring dynamic bending.

[0050] In one embodiment, the preset base film thickness of the first base film layer 11 and the second base film layer 21 is 12.5 μm, and the preset metal thickness of the first metal layer 12 and the second metal layer 22 is 12 μm. Then, the thickness of the first FPC single-panel body 1 is 37 μm, the thickness of the second FPC single-panel body 2 is 24.5 μm, and the overall thickness of the single-panel reusable structure is 66.5 μm.

[0051] It should be noted that the composite of single-layer wiring on the first FPC single-sided panel 1 and the second FPC single-sided panel 2 means that the first FPC single-sided panel 1 and the second FPC single-sided panel 2 are etched independently. This independent etching method effectively avoids the double-sided pattern alignment error commonly found in traditional double-sided panel designs, avoids conductive path deviation and welding defects caused by pattern layer asymmetry in multiple process steps, greatly improves the accuracy and reliability of the manufacturing process, reduces the defect rate in production, and improves the yield of the final product.

[0052] Referring to Table 1, the performance comparison test data of the single-sided reusable structure of this application and the single-sided single-layer wiring and double-sided double-sided copper-clad structures in related technologies are shown for the same thickness.

[0053] Performance comparison test LS / uH RS / mΩ RDC / mΩ Double-sided 8.52 310.25 283.3 single-sided 8.32 350.58 310.5 Composite board 8.45 332.67 295.2

[0054] Table 1

[0055] The single-sided reusable structure of this application improves the economy, reliability and electrical performance of wireless charging substrates. At the same time, it is suitable for smart terminal devices (such as foldable screen phones), automotive electronic devices and IoT devices, etc. It can withstand 65,000 bending cycles, which is 70% higher than the double-sided copper-clad structure. It does not delaminate after 500 hours in a high temperature and high humidity (85℃ / 85%RH) environment, and the adhesive layer 3 has a bonding strength of ≥1.5N / mm.

[0056] The single-sided reusable structure of this application solves the problems of double-sided copper-clad structures in related technologies, which require multiple patterning processes, resulting in low yield and cumbersome processes. The thickness of the substrate and the bonding strength of the copper layer are limited by the material properties, making it difficult to further reduce the thickness. Excessive substrate thickness affects its bending performance. This also solves the problems of single-sided structure designs in related technologies, which only have a single layer of wiring and cannot meet the current density and heat dissipation requirements of medium and high power wireless charging. Furthermore, the inductance (Q value) is limited by the thickness of a single copper layer, making it difficult to adapt to fast charging standards above 15W.

[0057] The present application has been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only for the purpose of helping to understand the core ideas of the present application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present application. Therefore, the content of this specification should not be construed as a limitation of the present application.

Claims

1. A single-panel multiplexing structure for a wireless charging system, comprising: include: A first FPC single-sided panel, a second FPC single-sided panel, and an adhesive layer, wherein the adhesive layer is disposed between the first FPC single-sided panel and the second FPC single-sided panel and connects the first FPC single-sided panel and the second FPC single-sided panel respectively. Both the first FPC single-sided panel and the second FPC single-sided panel have a metal line layer on the side away from the adhesive layer. The metal line layer of the first FPC single-sided panel has a plurality of connection through holes arranged thereon, and the metal line layer of the second FPC single-sided panel has connection pads corresponding to the connection through holes arranged thereon. The connection through holes are electrically connected to the connection pads. 2.The single-panel multiplexing structure for a wireless charging system of claim 1, wherein, The first FPC single-sided panel includes a first base film layer, a first metal layer, and a cover film layer stacked sequentially.

3. The single-panel multiplex structure for a wireless charging system as described in claim 2, characterized in that, The second FPC single-sided panel includes a second base film layer and a second metal layer stacked sequentially.

4. The single-panel multiplex structure for a wireless charging system as described in claim 3, characterized in that, The adhesive layer is bonded and fixed to the first base film layer and the second metal layer, respectively.

5. The single-panel multiplex structure for a wireless charging system as described in claim 1, characterized in that, The space between the connecting via and the connecting pad is filled with conductive adhesive or solder to achieve interlayer conductivity of the metal wire layer.

6. The single-panel multiplex structure for a wireless charging system as described in claim 1, characterized in that, On the vertical projection of the first FPC single-sided panel or the second FPC single-sided panel, the coverage area of ​​the connecting pad is greater than the coverage area of ​​the connecting via.

7. The single-panel multiplex structure for a wireless charging system as described in claim 1, characterized in that, The adhesive layer has a preset adhesive thickness, which includes 5±0.5um.

8. The single-panel multiplex structure for a wireless charging system as described in claim 3, characterized in that, The first base film layer and the second base film layer have a preset base film thickness, which includes 12.5±0.5um.

9. The single-panel multiplex structure for a wireless charging system as described in claim 3, characterized in that, The first metal layer and the second metal layer have a preset metal thickness, which includes 12±0.5um.

10. The single-panel multiplex structure for a wireless charging system as described in claim 2, characterized in that, The covering film layer has a preset covering thickness, which includes 12.5±0.5um.

Images