Double-sided coil structure
By forming a double-sided coil structure through a semi-additive process, combining additive and subtractive methods, and depositing a metal coating on the printed conductive layer, the pollution and performance issues in wireless charging coil production are solved, achieving low-pollution and high-performance coil manufacturing.
Patent Information
- Application Number
- CN202511394947.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-28
- Publication Date
- 2025-11-04
AI Technical Summary
Existing technologies for wireless charging coil production suffer from severe pollution and poor performance, particularly due to industrial pollution caused by traditional etching and insufficient conductivity in printing.
A double-sided coil structure is formed using a semi-additive process, where one side of the coil is formed by additive processing and the other side by subtractive processing. A metal plating layer is then formed on the printed conductive layer using a plating process, which reduces the etching range and improves conductivity.
It effectively reduces the amount of pollution and compensates for the insufficient conductivity of the printed conductive layer by using a metal plating layer, thereby improving the overall conductivity and stability of the coil.
Smart Images
Figure CN120895376A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application belongs to the technical field of electronic additive manufacturing, and particularly relates to a double-sided coil structure. BACKGROUND
[0002] Wireless charging refers to the transmission of energy between a charger and a power device through technical principles such as electromagnetic induction, magnetic field resonance, and electric field coupling, so that the connection of wires between the two can be cancelled, and a more convenient mobile charging method is realized. As electronic device products are becoming smaller and thinner, the size space left for wireless charging is also very limited, so many manufacturers design wireless charging coils by designing double-sided (or double-layer) coils for access combination.
[0003] At present, the production process of coils mainly includes traditional etching and printing methods. Traditional etching is to directly chemically etch copper foil to form a patterned coil structure. This process produces a large amount of industrial pollution, so there are great restrictions on the production region and production license. Printing is to use conductive paste to form a patterned coil structure by printing or printing, but due to the fact that the conductive paste is much lower than the conductive performance of copper foil, the thermal resistance is extremely large, which seriously limits the product performance. SUMMARY
[0004] Therefore, one object of the present application is to provide a double-sided coil structure to solve the problems of a large amount of pollution and poor product performance in the prior art.
[0005] In some illustrative embodiments, the double-sided coil structure comprises: an insulating substrate, a first coil formed on a first surface of the insulating substrate, and a second coil formed on a second surface of the insulating substrate; wherein the first coil and the second coil are connected through a metalized hole penetrating the insulating substrate; one of the first coil and the second coil comprises a printed conductive layer and a first metal plating layer formed thereon; the other coil comprises a metal foil etching layer.
[0006] In some optional embodiments, further comprising: a second metal plating layer formed on the metal foil etching layer; the first metal plating layer and the second metal plating layer are an integral structure.
[0007] In some optional embodiments, the first coil is a concentric coil of first sub-coils with the same number of turns, and the second coil is a spiral concentric coil of second sub-coils with a set number of turns; the first sub-coils and the second sub-coils correspond one by one, and each first sub-coil is connected to the corresponding second sub-coil through first and second metalized holes at the head and tail ends.
[0008] In some alternative embodiments, each of the first sub-coil is further connected with the second sub-coil through a third metalized hole located at the center of the head end and the tail end.
[0009] In some alternative embodiments, the surface height difference of the first metal plating layer is no more than 6 microns.
[0010] In some alternative embodiments, the printed conductive layer is formed by a low-temperature conductive paste.
[0011] In some alternative embodiments, the first coil and the second coil are multi-strand winding structures.
[0012] In some alternative embodiments, the first electrode end of the double-sided coil structure is led out from the inner edge of the first coil, and the second electrode end is led out from the outer edge of the second coil.
[0013] In some alternative embodiments, the first electrode end and the second electrode end are led out on the same side of the insulating substrate through a fourth metalized hole.
[0014] In some alternative embodiments, the insulating substrate is a soft board or a hard board.
[0015] Compared with the prior art, the present application has the following advantages:
[0016] The present application forms one side coil of the double-sided coil through additive method and the other side coil through subtractive method by semi-additive process, and then forms a metal plating layer on the printed conductive layer through plating process, which reduces the etching range of subtractive method, effectively reduces the pollution amount, and compensates for the poor conductive performance of the printed conductive layer formed by additive method through the metal plating layer. BRIEF DESCRIPTION OF DRAWINGS
[0017] Figure 1 is a structure example of the AB two sides of the double-sided coil structure in the embodiment of the present application;
[0018] Figure 2 is a layer structure example of the double-sided coil structure in the embodiment of the present application. DETAILED DESCRIPTION
[0019] To make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.
[0020] It should be noted that the technical features in the embodiments of the present application can be combined with each other without conflict.
[0021] The embodiments of the present application disclose a double-sided coil structure, specifically, as shown in Figures 1-2 Figure 1 The embodiments of the present application show the structure examples of the double-sided coil structure AB of the embodiments of the present application; Figure 2 The embodiments of the present application show the structure examples of the double-sided coil structure AB of the embodiments of the present application;The double-sided coil structure comprises: an insulating base material 10, a first coil 20 formed on a first surface A of the insulating base material 10, and a second coil 30 formed on a second surface B of the insulating base material 10; wherein the first coil 20 and the second coil 30 are connected through a metallized hole penetrating the insulating base material 10; one of the first coil 20 and the second coil 30 comprises: a printed conductive layer 61 and a first metal plating layer 62 formed thereon; the other coil comprises: a metal foil etching layer 71.
[0022] The present application forms one side coil of the double-sided coil through an additive method and the other side coil through a subtractive method by a semi-additive process, and then forms a metal plating layer on the printed conductive layer through a plating process, which reduces the etching range of the subtractive method, thereby effectively reducing the pollution amount, and the metal plating layer compensates for the poor conductivity of the printed conductive layer formed by the additive method.
[0023] The metallized hole in the embodiments of the present application can be formed by a black hole process, a black shadow process, a slurry hole plugging process, etc.
[0024] Since the printed conductive layer 61 and the metal foil etching layer 71 are interconnected through the metallized hole, the metal foil etching layer improves the overall conductivity of the printed conductive layer, which is conducive to improving the plating efficiency of the first metal plating layer.
[0025] In addition, based on the interconnection structure of the three, a unified metal plating layer can be formed on the printed conductive layer 61, the metal foil etching layer 71, and the metallized hole through a unified plating process, that is, a second metal plating layer 72 can also be formed on the metal foil etching layer 71, and the first metal plating layer 62, the metallized hole and the second metal layer 72 are a unified structure. In the embodiments, since the first metal plating layer and the second metal plating layer are a unified structure, the adhesion and structural stability of the overall first metal plating layer formed on the printed conductive layer can be improved.
[0026] In some embodiments, since the black hole process and the black shadow process are to form a conductive carbon structure (carbon powder or graphene) on the wall of the through hole, and then to metalize the wall through a plating process, the wall of the metallized hole can be formed at the same time as the metal plating layer on the printed conductive layer and the metal foil etching layer.
[0027] The structure of the first coil and the second coil and the combination manner therebetween in the embodiments of the present application can be set according to actual product requirements, and the present application does not limit the same.
[0028] In some preferred embodiments, the first coil in the embodiments of the present application can be a concentric coil with first sub-coils having the same set number of turns, and the second coil can be a spiral concentric coil with second sub-coils having a set number of turns; the first sub-coils and the second sub-coils correspond one by one, and each first sub-coil is connected to the corresponding second sub-coil through the first metallized hole 41 and the second metallized hole 42 at the head end and the tail end.
[0029] In the embodiments, the head end and the tail end of each first sub-coil are not connected, and need to be connected by the metallized hole and the second sub-coil. Preferably, the head ends of all the first sub-coils are located on the same radial line of the first coil, and the tail ends of all the first sub-coils are located on the same radial line of the first coil, and the two are close to each other but not interconnected.
[0030] In some embodiments, the first electrode end 51 of the double-sided coil structure is led out from the inner edge of the first coil 20, and the second electrode end 52 is led out from the outer edge of the second coil 30; wherein the first electrode end 51 is led out from the inner edge of the first coil 20, that is, the first electrode end 51 is connected with the first sub-coil on the innermost side of the first coil 20; the second electrode end 52 is led out from the outer edge of the second coil 30, that is, the second electrode end 52 is connected with the second sub-coil on the outermost side of the second coil 30.
[0031] In some preferred embodiments, the first electrode end 51 connected with the first sub-coil on the innermost side of the first coil 30 is led out from the gap between the head end and the tail end of each first sub-coil.
[0032] In some embodiments, the first electrode end 51 and the second electrode end 52 are led out on the same side of the insulating substrate 10 through the fourth metallized hole 44, thereby facilitating the external connection of the first electrode end 51 and the second electrode end 52.
[0033] In some embodiments, each first sub-coil can also be connected with the corresponding second sub-coil through the third metallized hole 53 located at the center of the head end and the tail end. Through this embodiment, the corresponding second sub-coil is connected again at the center of each first sub-coil, which is equivalent to shortening the connection distance between each first sub-coil formed by the printed conductive layer and the second sub-coil by half, which is beneficial to reduce the resistance difference of each region on each first sub-coil.
[0034] Further, by the above-mentioned case that the first sub-coil and the second sub-coil are connected through the third metallized hole 53, the overall flatness of the first metal plating layer can be improved during plating, and the thickness of each point of the first metal plating layer on each second sub-coil can be controlled within ±7% of the target thickness, or the surface height difference of the first metal plating layer on each second sub-coil can be reduced to not higher than 6 μm.
[0035] Therefore, the second metal plating layer can be formed by plating after the third metallized hole connection structure between the first sub-coil and the second sub-coil is formed.
[0036] The insulating substrate in the embodiments of the present application can be a hard board or a soft board, and the hard board includes but is not limited to FR-4, CEM-1, 22F, CEM-3, wood, glass, plastic, PMMA (acrylic), etc., and the soft board includes but is not limited to PET, PVC, PU, PC, PP, PA, PI, CPI (transparent PI), TPE, TPU, TPV, etc., and preferably, the insulating substrate in the embodiments of the present application can be PI or PET.
[0037] In some embodiments, the printed conductive layer is formed by a low-temperature conductive paste; wherein the low-temperature conductive paste mainly includes resin and conductive filler; wherein the conductive filler is not limited to one or more of gold, silver, copper, iron, nickel, zinc, aluminum, palladium, conductive carbon black, and graphene. The printed conductive layer can be formed by techniques such as screen printing, inkjet printing, pad printing, etc.
[0038] In some embodiments, the first coil and the second coil in the embodiments of the present application can be a multi-strand winding structure, such as a double-strand winding, a triple-strand winding, a four-strand winding, etc. In the drawings of the embodiments of the present application, a double-strand winding structure is given.
[0039] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the above embodiments, or make equivalent replacement for part 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 application.
Claims
1. A double-sided coil structure, characterized in that, include: An insulating substrate, a first coil formed on a first surface of the insulating substrate, and a second coil formed on a second surface of the insulating substrate; wherein the first coil and the second coil are connected through a metallized hole penetrating the insulating substrate; One of the first coil and the second coil includes: a printed conductive layer and a first metal plating layer formed thereon; the other coil includes: a metal foil etched layer.
2. The double-sided coil structure according to claim 1, characterized in that, Also includes: A second metal plating layer is formed on the metal foil etching layer; the first metal plating layer and the second metal plating layer are an integral structure.
3. The double-sided coil structure according to claim 1, characterized in that, The first coil is a concentric coil with the same set number of turns as the first sub-coil, and the second coil is a spiral concentric coil with the set number of turns as the second sub-coil; The first sub-coil and the second sub-coil are in one-to-one correspondence. Each first sub-coil is connected to its corresponding second sub-coil through a first metallized hole and a second metallized hole at its head and tail ends.
4. The double-sided coil structure according to claim 3, characterized in that, Each of the first sub-coils is also connected to the corresponding second sub-coil via a third metallized hole located at the center of the beginning and end.
5. The double-sided coil structure according to claim 4, characterized in that, The surface height difference of the first metal coating is no higher than 6 μm.
6. The double-sided coil structure according to claim 1, characterized in that, The printed conductive layer is formed from a low-temperature conductive paste.
7. The double-sided coil structure according to claim 1, characterized in that, The first coil and the second coil are multi-strand winding structures.
8. The double-sided coil structure according to claim 1, characterized in that, The first electrode of the double-sided coil structure is led out from the inner edge of the first coil, and the second electrode is led out from the outer edge of the second coil.
9. The double-sided coil structure according to claim 8, characterized in that, The first electrode and the second electrode are led out through a fourth metallized hole on the same side of the insulating substrate.
10. The double-sided coil structure according to claim 1, characterized in that, The insulating substrate is a flexible board or a rigid board.