Wireless charging circuit board

Abstract

The utility model discloses a wireless charging circuit board, and relates to the technical field of electronic additive manufacturing. The wireless charging circuit board comprises a magnetic layer, a first bonding layer, a first insulating film, a first printing layer, a first metal layer, a second bonding layer, a second insulating film, a second printing layer, a second metal layer, a third bonding layer and a third insulating film which are stacked in sequence, and the plated-through hole penetrates through the second bonding layer and the second insulating film and is used for realizing interconnection between the conductive structures on the two sides of the second insulating film. According to the embodiment of the utility model, the manufacturing of the double-sided conductive layer is completed by completely adopting an electronic additive manufacturing process, the thicknesses of the printing layer and the metal layer can be controlled according to actual design, incoming materials do not need to be considered, etching and copper reduction are not needed, the manufacturing process is simple, mature, efficient and low in cost, and meanwhile, a large amount of pollution like traditional etching cannot be generated.

Description

Technical Field

[0001] The utility model belongs to the technical field of electronic additive manufacturing, and particularly relates to a wireless charging circuit board. Background Art

[0002] Wireless charging technology, also known as wireless power transfer technology, is a new technology that enables energy transfer without the need for physical wire connections. It uses magnetic fields to transfer electrical energy from a power source to an electrical device, thus achieving wireless conduction of electricity. Its working principle is based on the principle of electromagnetic induction. When the power source transmitting end is energized, a magnetic field is generated in its coil, and the coil at the receiving end will sense this magnetic field and generate an induced current. This induced current is the energy source that provides electrical energy for the electrical device. Therefore, a wireless charging system mainly consists of two parts: a power source transmitting end and a receiving end.

[0003] Low-power wireless charging often uses the electromagnetic induction method, such as the Qi method for charging mobile phones. This method realizes wireless transmission of electrical energy through the principle of magnetic coupling. The receiving-end device usually uses a built-in battery. When placed above the charger, the coil at the receiving end receives the energy from the transmitting end through electromagnetic induction and stores the received electrical energy in the battery. The advantage of this method is that it is convenient and fast, eliminating the need to plug and unplug the charging cable, and improving the user experience.

[0004] Although the structure of a wireless charging circuit board is simple, it is undoubtedly the core component of wireless charging and has high requirements for indicators such as lightness and thinness. The current main technical route for wireless charging circuit boards is to use a combination of traditional etching and electroplating on a double-sided copper clad laminate. If the incoming copper clad is too thick, the copper clad needs to be thinned overall, resulting in low material utilization rate, increased processes and costs, and a large amount of pollutants are also generated during traditional etching, causing great damage to the environment. Summary of the Utility Model

[0005] In view of this, an object of the present utility model is to propose a wireless charging circuit board and its manufacturing method to solve the problems existing in the prior art.

[0006] In some illustrative embodiments, the wireless charging circuit board includes: a magnetic layer, a first adhesive layer, a first insulating film, a first printing layer, a first metal layer, a second adhesive layer, a second insulating film, a second printing layer, a second metal layer, a third adhesive layer, and a third insulating film, which are stacked in sequence; the first metal layer is formed by plating on the first printing layer and combines with the first printing layer to form a first conductive layer on one side of the second insulating film, and the second metal layer is formed by plating on the second printing layer and combines with the second printing layer to form a second conductive layer on the other side of the second insulating film; a metallized hole penetrating through the second adhesive layer and the second insulating film is used to interconnect the first conductive layer and the second conductive layer on both sides of the second insulating film.

[0007] In some alternative embodiments, the first adhesive layer and the first insulating film are coated substrates; and / or, the second adhesive layer and the second insulating film are coated substrates; and / or, the third adhesive layer and the third insulating film are coated substrates.

[0008] In some alternative embodiments, the magnetic layer is a nanocrystalline magnetic isolation sheet; and / or, the magnetic layer is a single-layer or multi-layer structure.

[0009] In some alternative embodiments, the first printing layer and / or the second printing layer and / or the metallized hole are formed by low-temperature conductive paste.

[0010] In some alternative embodiments, a wireless charging coil structure is formed on the first conductive layer or the second conductive layer, and the thickness of the metal layer in the conductive layer where the wireless charging coil structure is located is greater than the thickness of the metal layer in the other conductive layer; the sheet resistance of the first conductive layer and the second conductive layer is the same or close.

[0011] In some alternative embodiments, the wireless charging coil structure is formed on the second conductive layer.

[0012] In some alternative embodiments, the thickness of the wireless charging circuit board does not exceed 100 μm; and / or, the thickness of the first insulating film, the second insulating film, or the third insulating film does not exceed 10 μm.

[0013] In some alternative embodiments, the magnetic layer, the first insulating film, the second insulating film, and the third insulating film are flexible.

[0014] Another object of the present invention is to provide a method for manufacturing a wireless charging circuit board to solve the technical problems of the prior art.

[0015] In some illustrative embodiments, the method for manufacturing the wireless charging circuit board includes:

[0016] Step 1: Provide a magnetic layer;

[0017] Step 2: Provide a first coated substrate, and form it on the magnetic layer by using its coated surface;

[0018] Step 3: On the side of the first coated substrate away from its coated surface, form a first printed layer by using a first low-temperature conductive paste;

[0019] Step 4: Electroplate on the first printed layer to form a first metal layer;

[0020] Step 5: Provide a second coated substrate, and form it on the first metal layer by using its coated surface; wherein, the window position is at least used to form metallization holes for realizing conductive interconnection on both sides of the second coated substrate;

[0021] Step 6: On the side of the second coated substrate away from its adhesive surface, form a second printed layer by using a second low-temperature conductive paste, and at the same time cover the window to form the metallization holes;

[0022] Step 7: Electroplate on the second printed layer to form a second metal layer;

[0023] Step 8: Provide a third coated substrate, and make it composite on the second metal layer by using its coated surface.

[0024] Compared with the prior art, the present utility model has the following advantages:

[0025] In the embodiment of the present utility model, the production of the double-sided conductive layer is completely completed by using the electronic additive manufacturing process. The thickness of the printed layer and the metal layer can be controlled according to the actual design, without considering the incoming materials, without etching and copper reduction. The process is simple, mature, efficient, and low-cost, and at the same time, it will not produce a large amount of pollution such as traditional etching. Description of the Drawings

[0026] Figure 1 is a structural example of the wireless charging circuit board in the embodiment of the present utility model;

[0027] Figure 2 is a process example of the manufacturing method of the wireless charging circuit board in the embodiment of the present utility model. Detailed Embodiments

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present utility model clearer, the technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the drawings in the embodiments of the present utility model. Apparently, the described embodiments are some, but not all, of the embodiments of the present utility model. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0029] It should be noted that, without conflict, the technical features in the embodiments of the present utility model can be combined with each other.

[0030] An embodiment of the present utility model discloses a wireless charging circuit board. Specifically, as Figure 1-2 shown, Figure 1 is a structural example of the wireless charging circuit board in the embodiment of the present utility model; Figure 2 is a process example of the manufacturing method of the wireless charging circuit board in the embodiment of the present utility model; the wireless charging circuit board includes: a magnetic layer 1, a first adhesive layer 2, a first insulating film 3, a first printing layer 4, a first metal layer 5, a second adhesive layer 6, a second insulating film 7, a second printing layer 8, a second metal layer 9, a third adhesive layer 10, and a third insulating film 11 that are stacked in sequence; the first metal layer 5 is plated and formed on the first printing layer 4, and combines with the first printing layer 4 to form a first conductive layer 100 on one side of the second insulating film 7, and the second metal layer 9 is plated and formed on the second printing layer 8, and combines with the second printing layer 8 to form a second conductive layer 200 on the other side of the second insulating film 7; a metallized hole 12 that penetrates the second adhesive layer 6 and the second insulating film 7 is used to realize the interconnection between the first conductive layer 100 and the second conductive layer 200 on both sides of the second insulating film 7.

[0031] In the embodiment of the present utility model, the production of the double-sided conductive layer is completely completed by an electronic additive manufacturing process. The thickness of the printing layer and the metal layer can be controlled according to the actual design, without considering the incoming materials, without etching and copper reduction. The process is simple, mature, efficient, and low-cost, and at the same time, it will not generate a large amount of pollution such as traditional etching.

[0032] The insulating film in the embodiment of the present utility model may include: a flexible substrate and a rigid substrate, preferably a sheet or a film, etc.; wherein, the rigid substrate can be selected from traditional PCB boards, such as glass fiber boards, semi-glass fiber boards, specifically such as FR-4, CEM-1, 22F, CEM-3, etc. In addition to traditional PCB boards, wood, glass, plastic, PMMA (acrylic), etc. can also be used; and the flexible substrate can include a flexible stretchable substrate and a flexible non-stretchable substrate, such as PET, PVC, PU, PC, PP, PA, PI, CPI (transparent PI), TPE film materials, etc. In addition to the above substrates, PDMS, silica gel, fabric (such as non-woven fabric, nylon, washed cotton, polyester, spandex, and woven fabrics mixed with various materials), adhesive film (not limited to TPU, TPV), etc. can also be selected. Those skilled in the art should understand that in addition to the above substrates, the insulating film in the embodiment of the present utility model can also select other substrates in the prior art that can satisfy the formation of the conductive structure thereon.

[0033] The metal layer in the embodiment of the utility model can be formed by electroplating or chemical plating; preferably, it is formed by an electroplating process; wherein the metal layer can be a single-layer or multi-layer stacked structure, and its material is not limited to copper, gold, silver, nickel, zinc, etc.

[0034] In some embodiments, the first adhesive layer 2 and the first insulating film 3 are adhesive-coated substrates; and / or, the second adhesive layer 6 and the second insulating film 7 are adhesive-coated substrates; and / or, the third adhesive layer 10 and the third insulating film 11 are adhesive-coated substrates. Further, in the embodiment of the utility model, the first adhesive layer 2 and the first insulating film 3 are the first adhesive-coated substrate 300, the second adhesive layer 6 and the second insulating film 7 are the second adhesive-coated substrate 400, and the third adhesive layer 10 and the third insulating film 11 are the third adhesive-coated substrate 400. In this embodiment, the adhesive-coated substrate available on the market can be directly used, so there is no need to add the process of coating glue or adhesive film, which can reduce the process and improve efficiency.

[0035] The magnetic layer in the embodiment of the utility model can be a soft magnetic sheet, including but not limited to a nanocrystalline magnetic isolation sheet, which can be a single-layer or multi-layer structure; wherein the multi-layer structure is, for example, 2 layers, 3 layers, 4 layers, etc., each layer can be bonded by a film. The single-layer or multi-layer magnetic layer in this embodiment can be directly purchased from the market, and the utility model does not limit this.

[0036] Preferably, the magnetic layer 1 , the first insulating film 3 , the second insulating film 7 and the third insulating film 11 in the embodiment of the utility model can all be flexible, so as to realize a wireless charging flexible circuit board.

[0037] In some embodiments, the first printed layer 4 and / or the second printed layer 8 and / or the metallized hole 12 in the embodiment of the utility model are formed by low-temperature conductive paste. Further, the first printed layer 4, the second printed layer 8 and the metallized hole 12 in the embodiment of the utility model are all formed by low-temperature conduction; preferably, the metallized hole 12 can be formed by plugging the second printed layer 8 at the same time as the printing is implemented. The printing implementation method of the low-temperature conductive paste in this embodiment is not limited to screen printing, inkjet printing, transfer printing, etc.; preferably, it can be implemented by screen printing, which has the advantages of high efficiency, maturity, stability, and high yield compared to other printing methods.

[0038] The low-temperature conductive paste in the embodiment of the utility model refers to a composite conductive paste mainly composed of a conductive filler, a resin binder and a solvent. After the paste is fully cured, the solvent will fully evaporate, thereby converting it into a conductive film in which the conductive filler is bound by a resin film-forming material.

[0039] Among them, the conductive filler is not limited to one or at least two of metal particles, graphene, conductive carbon black, carbon nanotubes, and conductive particles such as core-shell structures; the metal particles are not limited to one or at least two of gold, silver, copper, iron, nickel, zinc, and silver-coated copper powder; the resin binder can be any resin on the market, including but not limited to one or at least two of epoxy resin, acrylic resin, naphthalene-containing epoxy resin, polyaryl epoxy resin, multi-functional epoxy resin, bismaleimide resin, and polyimide resin. The present application does not limit the selection of the solvent.

[0040] The curing method of the low-temperature conductive paste in the embodiment of the present utility model is not limited to thermosetting, photocuring, electromagnetic irradiation, or other curing methods.

[0041] In the embodiment of the present utility model, the first printing layer 4, the second printing layer 8, and the metallized hole 12 can be formed by the same low-temperature conductive paste or different low-temperature conductive pastes, and the present application does not limit this.

[0042] The printing thickness of the first printing layer 4 and / or the second printing layer 8 in the embodiment of the present utility model can be 1 to 10 μm; preferably, the thickness of the first printing layer 4 and / or the second printing layer 8 can be 3 to 5 μm, so as to further improve the structural strength and plating performance of the first printing layer 4 and the second printing layer 8.

[0043] Generally, the main structure of wireless charging mainly includes a wireless charging coil structure and two trace electrodes. One of the trace electrodes is on the same side of the carrier as the wireless charging coil structure, while the other trace electrode is on the other side of the carrier. The trace electrode on the same side as the wireless charging coil structure is usually connected to the outer edge of the wireless charging coil structure, and the trace electrode on the other side is connected to the inner edge of the wireless charging coil structure through a metallized hole. The other ends of the two trace electrodes will extend to the target position according to external wiring requirements.

[0044] The main structure for realizing wireless charging in the wireless charging circuit board in the embodiment of the present utility model is the first conductive layer 100, the second conductive layer 200, and the metallized hole 12 for realizing the electrical interconnection between the two; among them, the wireless charging coil structure can be formed on the first conductive layer 100 or the second conductive layer 200. At this time, the first trace electrode among the two trace electrodes is on the same side as the wireless charging coil structure, while the second trace electrode is on the other side far from the wireless charging coil structure.

[0045] In some embodiments, the thickness of the metal layer in the conductive layer where the wireless charging coil structure is located is greater than the thickness of the metal layer in another conductive layer. In this embodiment, mainly due to the limited size of the wireless charging coil, there are requirements for the number of coil turns. Therefore, its distribution density is relatively large, and its line width is usually made relatively small. Therefore, it is necessary to increase its thickness to ensure good conductivity. However, this will significantly increase the thickness of the wireless charging circuit board that is not desired.

[0046] In response to this, in the embodiments of the present invention, it is proposed that, when ensuring that the sheet resistance of the first conductive layer 100 and the second conductive layer 200 is the same or close, the thicknesses of the first conductive layer 100 and the second conductive layer 200 are designed to be inconsistent, so that the thickness of the second trace electrode (the conductive layer where it is located) is lower than the thickness of the wireless charging coil structure side (the conductive layer where it is located), so as to achieve the requirement of balancing or further reducing the thickness of the wireless charging circuit board. Specifically, since the laying density of the second trace electrode is low, the conductivity can be improved by increasing the line width of the second trace electrode, so as to ensure good conductivity consistency of the entire conductive structure.

[0047] Exemplarily, the wireless charging coil structure in the embodiments of the present invention is formed on the second conductive layer 200. The first printing layer 4 and the second printing layer 8 in the embodiments of the present invention are mainly used as the electroplating basis (seed layer) for the first metal layer 5 and the second metal layer 6. Therefore, their thicknesses only need to meet the requirements of printing and plating. The thicknesses of the first printing layer 4 and the second printing layer 8 can be the same or different, and the thickness of the first metal layer 5 should be less than that of the second metal layer 9, while the line width of the first metal layer 5 (the first printing layer) should be greater than that of the second metal layer 9 (the second printing layer).

[0048] When the wireless charging circuit board in the embodiments of the present invention is manufactured by a layer-by-layer stacking method, preferably, the wireless charging coil structure in the embodiments of the present invention is located on the second conductive layer, so as to reduce the height difference between the first conductive layer and the first insulating film, and reduce the influence of the surface flatness of the patterned first conductive layer coating film (the second insulating film) on subsequent printing.

[0049] On the other hand, the thickness of the first insulating film 3, the second insulating film 7 or the third insulating film 11 in the embodiments of the present utility model does not exceed 10 μm. Further, the thicknesses of the first insulating film 3, the second insulating film 7 and the third insulating film 11 in the embodiments of the present utility model all do not exceed 10 μm. In this embodiment, the first insulating film layer 3 is stacked on the magnetic layer 1, and the magnetic layer 1 can be used to strengthen the stress intensity of the first insulating film 3, so as to meet the printing requirements. Usually, the thickness of the substrate for printing load is at least 15 μm. With the above structure, a relatively thinner substrate can be selected, thereby further reducing the overall thickness of the wireless charging circuit board. Preferably, the thickness of the first to third insulating films can be selected from 1 to 15 μm. Further, the thickness of the first insulating film can be selected as 5 μm.

[0050] Further, the embodiments of the present utility model provide an example of the thickness of each structural layer of a wireless charging circuit board:

[0051]

[0052] Preferably, the thickness of the wireless charging circuit board in the embodiments of the present utility model does not exceed 100 μm.

[0053] The wireless charging circuit board in the embodiments of the present utility model can be formed by a layer-by-layer stacking method. Specifically, the manufacturing method includes:

[0054] Step S1: Provide a magnetic layer;

[0055] Step S2: Provide a first coated substrate, and form it on the magnetic layer by using its coated surface;

[0056] Step S3: On the side of the first coated substrate away from its coated surface, form a first printed layer by using a first low-temperature conductive paste;

[0057] Step S4: Electroplate a first metal layer on the first printed layer;

[0058] Step S5: Provide a second coated substrate, and form it on the first metal layer by using its coated surface; wherein, the window position is at least used to form metallization holes for realizing conductive interconnection on both sides of the second coated substrate;

[0059] Step S6: On the side of the second coated substrate away from its coated surface, form a second printed layer by using a second low-temperature conductive paste, and at the same time cover the window to form metallization holes;

[0060] Step S7: Electroplate a second metal layer on the second printed layer;

[0061] Step S8: Provide a third coated substrate, and make it composite on the second metal layer by using its coated surface.

[0062] Among them, the above-mentioned coated substrates are all of the structure of insulating film + adhesive layer.

[0063] In the embodiment of the present invention, it can be gradually formed directly on the magnetic layer by a layer-by-layer stacking method. The stress intensity requirement for the first coated substrate can be reduced depending on the structural strength of the magnetic layer. Therefore, it is optional to perform printing operations on an insulating film with a relatively thinner thickness of less than 10 μm, so as to reduce the thickness of the entire wireless charging circuit board. Furthermore, the wireless charging coil structure can be arranged on the second conductive layer, so as to reduce the thickness of the first conductive layer and reduce the influence of the surface flatness of the patterned first conductive layer coating film (the second coated substrate) on subsequent printing.

[0064] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A wireless charging circuit board, characterized in that, Including: A magnetic layer, a first adhesive layer, a first insulating film, a first printing layer, a first metal layer, a second adhesive layer, a second insulating film, a second printing layer, a second metal layer, a third adhesive layer, and a third insulating film stacked in sequence; The first metal layer is formed by plating on the first printing layer and combines with the first printing layer to form a first conductive layer on one side of the second insulating film, and the second metal layer is formed by plating on the second printing layer and combines with the second printing layer to form a second conductive layer on the other side of the second insulating film; A metallization hole penetrating through the second adhesive layer and the second insulating film is used to interconnect the first conductive layer and the second conductive layer on both sides of the second insulating film.

2. The wireless charging circuit board according to claim 1, wherein The first adhesive layer and the first insulating film are adhesive-coated substrates; and / or, the second adhesive layer and the second insulating film are adhesive-coated substrates; and / or, the third adhesive layer and the third insulating film are adhesive-coated substrates.

3. The wireless charging circuit board according to claim 1, characterized in that The magnetic layer is a nanocrystalline magnetic isolation sheet; and / or, the magnetic layer has a single-layer or multi-layer structure.

4. The wireless charging circuit board according to claim 1, characterized in that, The first printing layer and / or the second printing layer and / or the metallization hole are formed by low-temperature conductive paste.

5. The wireless charging circuit board according to claim 1, wherein A wireless charging coil structure is formed on the first conductive layer or the second conductive layer, and the thickness of the metal layer in the conductive layer where the wireless charging coil structure is located is greater than the thickness of the metal layer in the other conductive layer; the sheet resistance of the first conductive layer and the second conductive layer is the same or close.

6. The wireless charging circuit board according to claim 5, characterized in that, The wireless charging coil structure is formed on the second conductive layer.

7. The wireless charging circuit board according to claim 5, wherein, The thickness of the wireless charging circuit board does not exceed 100 μm.

8. The wireless charging circuit board according to claim 1, characterized in that, The thickness of the first insulating film, the second insulating film, or the third insulating film does not exceed 10 μm.

9. The wireless charging circuit board according to claim 1, wherein The magnetic layer, the first insulating film, the second insulating film, and the third insulating film are flexible.

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