WO2019227644A1 - Shielding sheet for wireless charging module and wireless charging module - Google Patents

Abstract

Disclosed by the present invention are a shielding sheet for a wireless charging module and a wireless charging module, comprising an outer-ring magnetic sheet and a central magnetic conductor; a hole fitted to the central magnetic conductor is formed on the outer-ring magnetic sheet; the central magnetic conductor is fixed in the hole; the outer-ring magnetic sheet includes at least one layer of nanocrystalline strip; and the central magnetic conductor is a soft magnetic ferrite, or the central magnetic conductor is a cylindrical object formed by stacking multiple layers of magnetic powder core films. The shielding sheet is small in size, low in manufacturing cost, and improves the charging efficiency of the wireless charging module.

Description

Shielding sheet for wireless charging module and wireless charging module Technical field

The invention relates to the technical field of wireless charging, in particular to a shielding sheet for a wireless charging module and a wireless charging module.

Background technique

Wireless charging technology is a method that uses near-field electromagnetic induction to transmit energy from the transmitting end to the wireless charging receiving coil through a magnetic field. Compared with electric field coupling, the wireless charging technology based on the magnetic field coupling principle is closer to the conventional resonant switching power supply.

In order to obtain higher charging efficiency and reduce the influence of electromagnetic fields on electronic devices during charging, magnetic materials need to be used. The role of magnetic materials is to distribute the magnetic field in high-permeability magnetic materials, prevent the magnetic field from passing through the magnetic materials and reach the interior of the electronic equipment, and cause the metal (battery) and other components inside the electronic equipment to absorb the magnetic field, resulting in energy loss and electromagnetic interference. Taking a mobile phone as an example, the location next to the wireless charging coil is generally the battery. When the alternating magnetic field generated by the transmitting coil passes through the charging module and reaches the metal layer on the surface of the battery, an induced current will be generated. This is the so-called "eddy current". This eddy current will generate a magnetic field that cancels out the change of the magnetic field at the transmitting end, which will cause the voltage induced in the receiving coil to drop; and the eddy current will convert the energy of the magnetic field into heat, making the mobile phone battery very hot. Therefore, in order to achieve wireless charging of the mobile phone, it is necessary to place a "isolating magnetic field" device between the receiving coil and the mobile phone battery to avoid the magnetic field from affecting the battery. The receiver of Samsung mobile phone wireless charging adopts the amorphous electromagnetic shielding sheet technology provided by Amotech, and the charging efficiency reaches more than 70%. Amotech's patented solution is a technology that uses pressure roller crushing to break the amorphous metal and form irregular random cracks in the material to reduce the magnetic loss μ "to a certain range (≤200) to reduce the loss of the material itself. However, this solution also has some Disadvantages that are difficult to overcome: ① "Magnetic fragmentation" also reduces the magnetic permeability μ 'significantly, which results in a decrease in the magnetic permeability of single-layer magnetic materials. Therefore, the current wireless charging magnetic materials using this technology need to increase the amorphous The number of material layers avoids the problem of increased losses due to magnetic leakage (eddy current on the battery), so the product is relatively thick; ② "Magnetic fragmentation" is a "random" and "statistical" process method in principle. The magnetic permeability cannot be accurately controlled, the process cannot accurately control the material parameters, the product yield is not high, and the process cost is high.

In summary, although the wireless charging market has a bright future, there are still some insurmountable problems in the existing technical solutions, such as the disadvantages of low charging efficiency, high cost, complex process and low yield. For wireless charging technology to be rapidly promoted and popularized in the field of consumer electronics, it is necessary to make breakthroughs in the following areas: 1. To ensure the efficiency of charging, reduce the thickness of wireless charging modules as much as possible; 2. Reduce the production of wireless charging modules cost.

technical problem

The technical problem to be solved by the present invention is to provide a shielding sheet for a wireless charging module that is small in size and is beneficial to improve the charging efficiency, and a wireless charging module.

Technical solutions

In order to solve the above technical problems, the technical solution adopted by the present invention is: a shielding sheet for a wireless charging module, which includes an outer ring magnetic sheet and a center magnet, and the outer ring magnetic sheet is provided with a matching piece to the center magnet. A hole; the central magnetically permeable magnet is fixed in the hole; the outer ring magnetic sheet includes at least one magnetically permeable layer, and the magnetically permeable layer is a nanocrystalline strip, an amorphous strip, or a metal soft magnetic tape; The central magnetizer is a soft ferrite, or the central magnetizer is a columnar body formed by laminating a plurality of magnetic powder core films.

In order to solve the above technical problems, the present invention also adopts the following technical solution: the wireless charging module includes a charging coil and a shielding sheet for the wireless charging module, and the shielding sheet for the wireless charging module includes an outer ring magnetic sheet and a center magnet, An outer ring magnetic plate is provided with a hole adapted to the central magnetic guide; the central magnetic guide is fixed in the hole; the outer magnetic plate includes at least one magnetic conductive layer, and the magnetic conductive layer is Nanocrystalline strip, amorphous strip or metal soft magnetic tape; the hole is located in the hollow area of the charging coil; the central magnet is a soft ferrite, or the central magnet is made of multiple layers A columnar body formed by laminating magnetic powder core films.

Beneficial effect

The beneficial effect of the present invention is that since the outer ring magnetic sheet is perpendicular to the direction of the induced eddy current, when the outer ring magnetic sheet is laminated with multiple nanocrystalline strips, there is an insulating glue between the laminated nanocrystalline strips, so regardless of the outer ring magnetism How high is the sheet magnetic loss μ ”, and it does not generate long free path eddy currents (when the outer ring magnetic sheet has only one layer of nanocrystalline strip, the thickness of a single layer of nanocrystalline strip is thin, and no long free Range eddy current), so the outer ring magnetic sheet not only maintains high magnetic permeability, but also has low eddy current loss; the magnetic field lines in the hollow area of the charging coil are perpendicular to the outer ring magnetic sheet, making use of higher insulation Soft ferrite (or laminated magnetic powder core film) as the central magnet can effectively hinder the generation of eddy current inside the central magnet. Under the same shielding performance, the number of laminated outer magnetic sheets is smaller and embedded in the outer magnet. The center conductor in the sheet will not increase the thickness of the shielding sheet, so it is conducive to the miniaturization of the shielding sheet, and at the same time the charging efficiency is improved; there is no need to use "air gap" or "insulation crack" in the material. Arts, can shorten the process and lower the manufacturing process more expensive raw material used in an amount (nanocrystals, pressure sensitive, etc.), to improve product yield and reduce production cost of the wireless charging module.

BRIEF DESCRIPTION OF THE DRAWINGS

1 is a cross-sectional (schematic) view of a shielding sheet for a wireless charging module according to a first embodiment of the present invention;

2 is a schematic (schematic) diagram of a shielding sheet for a wireless charging module according to a first embodiment of the present invention;

3 is a cross-sectional (schematic) view of another shielding sheet for a wireless charging module according to the first embodiment of the present invention.

Label description:

1. Magnetic disk of outer ring;

2, central ferrite;

3. holes;

4. Adhesive layer;

5. Outer ring magnets;

6. Charging coil;

7. Insulating rubber layer.

Embodiments of the invention

In order to explain the technical content, achieved objectives, and effects of the present invention in detail, the following describes in combination with the embodiments and the accompanying drawings.

The most important idea of the present invention is: a hole is provided at the position of the outer ring magnetic sheet corresponding to the hollow area of the charging coil, and a central magnet is disposed in the hole; the outer magnetic sheet has the characteristics of high magnetic permeability and high shielding property, and the central magnet has Low magnetic loss and high resistance.

Please refer to FIG. 1 to FIG. 3, a shielding sheet for a wireless charging module includes an outer ring magnetic sheet 1 and a center magnet 2. The outer ring magnetic sheet 1 is provided with a hole adapted to the center magnet 2. 3; the central magnetic guide 2 is fixed in the hole 3; the outer ring magnetic sheet 1 includes at least one magnetic permeable layer, and the magnetic permeable layer is a nanocrystalline tape, an amorphous tape, or a soft metal tape When the number of magnetically permeable layers is greater than or equal to 2, two adjacent magnetically permeable layers are stacked and the two adjacent magnetically permeable layers are connected by an insulating glue; the central magnetically permeable layer 2 is a soft ferrite, or The central magnet 2 is a columnar body formed by laminating multiple magnetic powder core films.

The structural principle of the present invention is briefly described as follows: magnetic lines of force perpendicular to the outer ring magnetic sheet will induce eddy current loss in the surface of the center magnet, but the center magnet (ferrite and magnetic powder core film) itself has high insulation and low magnetic loss characteristics Will suppress the generation of eddy currents and losses; and magnetic lines of force parallel to the outer magnetic disk will induce eddy currents perpendicular to the outer magnetic disk, because the nanocrystalline, amorphous layer or other metal flexible magnetic tape material in the outer magnetic disk is very thin (Only 10-30 μm), and there is an insulating polymer glue between the layers, the outer ring magnetic sheet itself cannot generate a large eddy current.

It can be known from the above description that the beneficial effect of the present invention is that since the outer ring magnetic sheet is perpendicular to the direction of the induced eddy current, when the outer ring magnetic sheet is laminated with a plurality of nanocrystalline strips, there is an insulating glue between the laminated nanocrystalline strips. Therefore, no matter how high the magnetic loss μ ”of the outer ring magnetic sheet is, it will not generate a long free path eddy current itself. (When the outer ring magnetic sheet has only one layer of nanocrystalline strip, the thickness of the single layer of nanocrystalline strip is thinner. No long free path eddy current is generated), so the outer ring magnetic sheet not only maintains high magnetic permeability but also has low eddy current loss. The magnetic field lines in the hollow area of the charging coil are perpendicular to the outer ring magnetic sheet. The soft ferrite (or laminated magnetic powder core film) with high insulation as the central magnet can effectively prevent the generation of eddy currents inside the central magnet. Under the same shielding performance, the number of laminated outer ring magnetic sheets is more. Less, the central magnet embedded in the outer magnetic sheet will not increase the thickness of the shielding sheet, so it is conducive to the miniaturization of the shielding sheet, and at the same time the charging efficiency is improved; there is no need to add "air gap" in the material Process or "crack insulating" can be shortened and the process technology to reduce the amount of relatively expensive starting material (nanocrystals, pressure-sensitive adhesive, etc.).

Further, one end of the center magnet 2 is located in the hole 3, and the other end of the center magnet 2 protrudes from the outer ring magnetic sheet 1.

It can be known from the above description that the thickening of the center magnet can further increase the shielding performance of the center magnet, thereby further improving the charging efficiency of the wireless charging module.

Further, the hole 3 is a through hole adapted to the central magnet 2, and the top surface of the outer ring magnetic sheet 1 and the top surface of the central magnet 2 are coplanar.

Further, an adhesive layer 4 is provided on a top surface of the outer ring magnetic sheet 1, and a top surface of the center magnet 2 is connected to the adhesive layer 4.

It can be known from the above description that the shielding sheet has a simple structure and is easy to manufacture.

Further, it further comprises an outer ring magnet 5 connected to the outer ring magnetic sheet 1. The outer ring magnet 5 is provided with a through hole for accommodating the charging coil 6 in the wireless charging module. The central magnet 2 is located at Inside the through hole; the top surface of the outer ring magnet 5 is coplanar with the top surface of the outer ring magnet 1, and the bottom surface of the outer ring magnet 5 protrudes from the outer ring magnet 1 Bottom surface

The outer ring magnetizer 5 is a soft ferrite, or the outer ring magnetizer 5 is a columnar body formed by laminating a plurality of magnetic powder core films.

From the above description, it can be known that considering that the magnetic field lines on the outer edge of the charging coil are also perpendicular to the plane of the charging coil and the same principle as the central magnetism, setting a low loss and high insulation magnetism on the periphery of the charging coil is also beneficial to further reduce the shielding sheet loss. To improve the charging efficiency of wireless charging modules.

Further, the bottom surface of the outer ring magnet 5 and the bottom surface of the central magnet 2 are coplanar.

The wireless charging module includes a charging coil 6 and a shielding sheet for the wireless charging module. The shielding sheet for the wireless charging module includes an outer ring magnetic sheet 1 and a center magnet 2. A hole 3 adapted to the center magnetic guide 2; the center magnetic guide 2 is fixed in the hole 3; the outer ring magnetic sheet 1 includes at least one magnetic conductive layer, and the magnetic conductive layer is a nanocrystalline strip , Amorphous tape or metal flexible magnetic tape; when the number of magnetically permeable layers is greater than or equal to 2, two adjacent magnetically permeable layers are stacked and two adjacent magnetically permeable layers are connected by an insulating glue; said hole 3 The central magnet 2 is a soft ferrite, or the central magnet 2 is a columnar body formed by stacking multiple magnetic powder core films.

Further, one end of the center magnet 2 is located in the hole 3, the other end of the center magnet 2 protrudes from the outer ring magnetic sheet 1, and the inner edge surface of the charging coil 6 and the center magnet The outer edge surfaces of the magnet 2 are in conflict.

Further, it further comprises an outer ring magnet 5 connected to the outer ring magnetic sheet 1. The outer ring magnet 5 is provided with a through hole, the central magnet 2 is located in the through hole, and the outer portion of the charging coil 6 The edge surface is in conflict with the inner edge surface of the outer ring magnet 5;

The outer ring magnetizer 5 is a soft ferrite, or the outer ring magnetizer 5 is a columnar body formed by laminating a plurality of magnetic powder core films.

Further, the top surface of the outer ring magnet 5 is coplanar with the top surface of the center magnet 2, and the bottom surface of the outer ring magnet 5 and the bottom surface of the center magnet 2 are located on the same side of the outer ring magnet 1. side.

Example one

1 and FIG. 2, a first embodiment of the present invention is: a wireless charging module including a charging coil 6 and a shielding sheet for the wireless charging module. The shielding sheet for the wireless charging module includes an outer ring magnetic sheet 1 and The center magnet 2 is provided with a hole 3 adapted to the center magnet 2 on the outer ring magnetic sheet 1; the center magnet 2 is fixed in the hole 3; the outer ring magnetic sheet 1 includes at least A magnetic permeable layer, the magnetic permeable layer is a nanocrystalline tape, an amorphous tape, or a high-permeability metal soft magnetic tape; the hole 3 is located in a hollow region of the charging coil 6. Optionally, the charging coil 6 is bonded to the outer ring magnetic sheet 1 of the shielding sheet through a pressure-sensitive adhesive.

The metal soft magnetic tape includes, but is not limited to, industrial pure iron tape, Fe-Si tape, and permalloy tape. When the number of magnetically permeable layers is greater than or equal to two, two adjacent magnetically permeable layers are stacked and the two adjacent magnetically permeable layers are connected by an insulating adhesive, for example, by an acrylic adhesive, to prevent the outer magnetic sheet 1 Generate long free path vortices.

Preferably, the outer ring magnetic sheet 1 is formed by stacking 2 or 3 layers of nanocrystalline strips, and the thickness of the nanocrystalline strips is 10-30 μm. The central magnet 2 can be selected from soft ferrites, such as Mn-Zn ferrite and Ni-Zn ferrite highly insulating magnetic materials. The central magnet 2 can also be a columnar shape formed by stacking multiple magnetic powder core films. The body is, for example, a columnar body formed by laminating a multilayer FeSi magnetic powder core, a FeSiAl magnetic powder core, and a FeNi magnetic powder core film. Adjacent two layers of the magnetic powder core film may be bonded with an insulating glue.

In this embodiment, a soft ferrite is selected as the central magnet. Specifically, the outer ring magnetic sheet 1 is a nanocrystalline strip with a magnetic permeability greater than or equal to 5000, the outer ring magnetic sheet 1 is an amorphous strip with a magnetic permeability greater than 1,000, or the outer ring magnetic sheet 1 is a magnetic permeability Flexible metal tape greater than or equal to 800.

The magnetic permeability of the central magnet 2 (ie, soft ferrite) is 200-6000 or higher.

One end of the center magnet 2 is located in the hole 3, the other end of the center magnet 2 protrudes from the outer ring magnetic sheet 1, and the inner edge of the charging coil 6 is attached to the center magnet 2 peripheral walls. Of course, it is feasible that the other end of the center magnet 2 is concave with respect to the outer ring magnetic sheet 1, or the other end of the center magnet 2 is flush with the outer ring magnetic sheet 1.

Preferably, the hole 3 is a through hole adapted to the center magnet 2, and the top surface of the outer ring magnetic sheet 1 and the top surface of the center magnet 2 are coplanar.

In detail, an adhesive layer 4 is provided on the top surface of the outer ring magnetic sheet 1, and the top surface of the center magnet 2 is connected to the adhesive layer 4. Preferably, the adhesive layer 4 is a pressure-sensitive acrylic adhesive layer. When the top surface of the outer ring magnetic sheet 1 is not provided with the adhesive layer 4, an interference fit between the central magnet 2 and the outer ring magnetic sheet 1 may be selected.

Further, the bottom surface of the charging coil 6 and the bottom surface of the central magnet 2 are adhered to the same insulating layer 7 (for example, an acrylic adhesive layer).

The manufacturing method of the wireless charging module,

Step 1: Provide nanocrystalline strip and soft ferrite (or a columnar body formed by laminating magnetic powder core film), and heat-treating the nanocrystalline strip;

Step 2: Glue the nanocrystalline strip after Step 1;

Step 3: Laminate the N-coated nanocrystalline strips and bond two adjacent nanocrystalline strips to obtain a nanocrystalline magnetic sheet, where N is an integer greater than or equal to 1; preferably, said N is 2 or 3.

Step 4: Die-cut contour and through-hole processing are performed on the nanocrystalline magnetic sheet to obtain an outer ring magnetic sheet;

Step 5: Die-cut the contour processing of the soft ferrite (or the cylindrical body formed by laminating the magnetic powder core film) to obtain a central magnet;

Step 6: Insert one end of the center guide magnet into the through hole, and make the top surface of the center guide magnet and the top surface of the outer ring magnetic sheet coplanar;

Wherein, step 5 may be located before step 2, step 3 or step 4; the central magnet is adapted to the through hole.

Further, after step 6, there is step 7: sticking the top surface of the center magnet and the top surface of the outer ring magnetic sheet to the same adhesive layer.

After the assembler has installed the charging coil, that is, the top surface of the charging coil is attached to the outer ring magnetic sheet. After the inner edge of the charging coil is attached to the outer edge of the center magnet, the bottom surface of the charging coil and the central ferrite need to be attached. The bottom surface of the body is adhered to an insulating layer to complete the manufacture of the wireless charging module.

The inventor made a batch of samples and tested them.

Nanocrystalline alloy strip grade: 1K107b, thickness is 20μm.

Center magnet: Mn-Zn ferrite.

The heat treatment furnace (for example, a nitrogen furnace) is used to heat treat the nanocrystalline strip. The specific process of heat treatment is as follows: first, the nanocrystalline strip is heated to 600 ° C with the furnace, and then maintained for 2 hours, and then cooled to 250 ° C at a rate of 600 ° C / h and released.

Single-sided lamination of the heat-treated tape; lamination of single-sided coated nanocrystalline tapes to obtain 3 layers of nanocrystalline magnetic sheet (outer ring magnetic sheet) and 2 layers of nanocrystalline magnetic sheet (outer ring magnetic sheet) Slice), its parameters are shown in Table 1.

Table 1 Parameter table of outer ring magnetic sheet and first ferrite

project	Numbering	Layers	Thickness (μm)	Permeability μ ’	Magnetic loss μ "
Outer ring magnet	L3	3	80	12655	3210
Outer ring magnet	L2	2	55	12780	3119
Mn-Zn ferrite	F6	1	150	605	7.1
Mn-Zn ferrite	F4	1	150	389	4.5

Die-cut the outer ring magnetic sheet and Mn-Zn ferrite respectively, and die-cut two or three layers of nanocrystalline materials according to the external dimensions of the wireless charging module design and the inner diameter of the charging coil to remove the high magnetic permeability in the through hole Rate nanocrystalline magnetic material; die-cut iron Mn-Zn ferrite according to the inner diameter of the charging coil to prepare a central ferrite that matches the inner diameter of the nanocrystal;

Use a laminator to attach the central ferrite (that is, the central magnet) to the through hole of the outer ring magnetic sheet with a pressure roller, so that its edge completely matches the inner wall surface of the through hole, so that the top surface of the central ferrite Coplanar with the top surface of the outer ring magnetic sheet and adhere the two with acrylic glue to form a shielding sheet;

Test: The prepared samples 1 to 4 are assembled with the charging coil and other components to obtain a wireless charging module, and the wireless charging module is tested for electrical performance. In order to better compare with the shielding sheet made by the traditional process, the inventor also added the wireless charging module corresponding to the 3-layer and 5-layer nanocrystalline shielding sheet made by the traditional process as the comparison samples 5 and 6, and the test results of the sample are Table 2 shows.

Table 2 Comparison table of sample test results

Serial number	Combination	Coil inductance L / μH	Figure of merit Q
Sp1	L3F6	8.31	20.1
Sp2	L3F4	8.29	19.8
Sp3	L2F6	8.28	19.7
Sp4	L2F4	8.25	19.6
Sp5	3 layers of nanocrystals (μ ’= 800)	7.85	18.5
Sp6	5 layers of nanocrystals (μ ’= 800)	8.18	19.2

As can be seen from Table 2, the overall inductance of the wireless charging module using the shielding sheet of the present invention is higher than that of Comparative Sample 5 and Sample 6, and the Q value also increases to some extent.

A 5W platform was used to compare the charging efficiency of samples 1-6. The test results are shown in Table 3.

Table 3 Comparison table of 5W platform charging efficiency test

As shown in Table 3, through a comparative analysis of charging efficiency, the charging efficiency of a wireless charging module using the shielding sheet of the present invention is much higher than that of a wireless charging module using a conventional shielding sheet of the same number of layers. Compared with the five-layer nanocrystalline magnetic material, the charging efficiency is also improved by about 0.3 to 1%.

Compared with the wireless charging magnetic materials on the market today, the nanocrystalline ferrite composite shielding sheet can maintain or achieve ultra-thin (80μm) charging efficiency and reach or exceed the highest charging that can be achieved with traditional 5-layer nanometer (140μm) crystals. At the same time, because the new structure magnetic material does not require traditional nanocrystalline magnetic sheet manufacturing processes such as fragmentation, it can improve product yield, reduce labor, equipment and raw material input, and greatly reduce the cost of wireless charging magnetic materials.

Example two

Please refer to FIG. 3, the second embodiment of the present invention is based on the first embodiment to further improve the shielding sheet for the wireless charging module and the wireless charging module, which is different from the wireless charging module in the embodiment. The wireless charging module in this embodiment further includes an outer ring magnet. Specifically, the wireless charging module includes a charging coil 6 and a shielding sheet for the wireless charging module. The shielding sheet for the wireless charging module includes an outer ring magnet. The sheet 1 and the center magnet 2 are provided with a hole 3 adapted to the center magnet 2 on the outer ring magnet 1; the center magnet 2 is fixed in the hole 3; the outer ring magnet 1 includes at least one magnetically permeable layer, the magnetically permeable layer is a nanocrystalline strip, an amorphous strip, or a high-permeability metal soft magnetic tape; the hole 3 is located in a hollow region of the charging coil 6. Optionally, the charging coil 6 is bonded to the outer ring magnetic sheet 1 of the shielding sheet through a pressure-sensitive adhesive.

When the number of nanocrystalline strips in the outer magnetic sheet 1 is 2 or more, the adjacent two layers of nanocrystalline strips can be bonded by a polymer insulating adhesive (such as acrylic adhesive) to prevent the outer magnetic sheet. A long free path vortex is generated in 1. Preferably, the outer ring magnetic sheet 1 is formed by stacking two or three nanocrystalline strips; the thickness of the nanocrystalline strips is 10-30 μm.

The central magnet 2 can be selected from soft ferrites, such as Mn-Zn ferrite and Ni-Zn ferrite high-insulation materials; the central magnet 2 can also be a columnar body formed by stacking multiple magnetic powder core films. For example, a columnar body is formed by stacking a plurality of magnetic powder core films such as FeSiAl, FeSi, FeNi, and the adjacent two layers of magnetic powder core films may be bonded with an insulating glue.

In this embodiment, a soft ferrite is selected as the central magnet. Specifically, the outer ring magnetic sheet 1 is a nanocrystalline strip with a magnetic permeability greater than or equal to 5000, the outer ring magnetic sheet 1 is an amorphous strip with a magnetic permeability greater than 1,000, or the outer ring magnetic sheet 1 is a magnetic permeability A metal flexible magnetic tape material greater than or equal to 800; the magnetic permeability of the central magnet 2 (ie, soft ferrite) is 200-6000.

One end of the center magnet 2 is located in the hole 3, and the other end of the center magnet 2 protrudes from the outer ring magnetic sheet 1. The inner edge surface of the charging coil 6 and the center magnet 2 are The outer edge faces are in conflict.

Preferably, the hole 3 is a through hole adapted to the center magnet 2, and the top surface of the outer ring magnetic sheet 1 and the top surface of the center magnet 2 are coplanar.

In detail, an adhesive layer 4 is provided on the top surface of the outer ring magnetic sheet 1, and the top surface of the center magnet 2 is connected to the adhesive layer 4. Preferably, the adhesive layer 4 is a pressure-sensitive acrylic adhesive layer. When the top surface of the outer ring magnetic sheet 1 is not provided with the adhesive layer 4, an interference fit between the central magnet 2 and the outer ring magnetic sheet 1 may be selected.

Further, it further comprises an outer ring magnet 5 connected to the outer ring magnetic sheet 1. The outer ring magnet 5 is provided with a through hole for accommodating the charging coil 6 in the wireless charging module. The central magnet 2 is located at Inside the through hole; the top surface of the outer ring magnet 5 is coplanar with the top surface of the outer ring magnet 1, and the bottom surface of the outer ring magnet 5 protrudes from the outer ring magnet 1 Underside. Preferably, the outer edge surface of the charging coil 6 is in conflict with the inner edge surface of the outer ring magnet 5;

The outer ring magnetizer 5 is a soft ferrite, or the outer ring magnetizer 5 is a columnar body formed by laminating a plurality of magnetic powder core films.

Preferably, the bottom surface of the outer ring magnet 5, the bottom surface of the center magnet 2 and the bottom surface of the charging coil 6 are coplanar. Further preferably, the bottom surface of the outer ring magnet 5, the bottom surface of the center magnet 2 and the bottom surface of the charging coil 6 are adhered to the same insulating layer 7 (for example, an acrylic adhesive layer).

In this embodiment, the principle of setting the outer magnet 5 is similar to the principle of setting the central magnet 2. The magnetic field lines outside the charging coil 6 are the same as the magnetic field lines in the hollow region of the charging coil 6, and are perpendicular to the outer ring magnetic sheet 1. Then this position can also use magnetic materials with low permeability and low loss to achieve the purpose of further improving the charging efficiency.

Compared with the traditional magnetic shielding sheet, the shielding sheet for the wireless charging module and the wireless charging module provided by the present invention have a smaller number of laminated outer ring magnetic sheets and high magnetic loss under the same shielding performance. The insulating center magnet is just embedded in the center of the coil and does not affect the thickness of the module, so it is conducive to the miniaturization of the shielding sheet and the charging efficiency is improved; there is no need to add any "air gap" or " "Insulation crack" process can shorten the process and reduce the use of raw materials, thereby improving product yield and reducing the production cost of wireless charging modules.

In summary, the nanocrystalline composite shielding sheet of the present invention has absolute advantages in terms of ultra-thinness, high charging efficiency, and cost, and can meet the demand for wireless charging development of consumer electronics products.

The above description is only an embodiment of the present invention, and thus does not limit the patent scope of the present invention. Any equivalent transformation made by using the content of the description and drawings of the present invention, or directly or indirectly used in related technical fields, is included in the same reason. Within the scope of patent protection of the present invention.

Claims (10)

1. A shielding sheet for a wireless charging module is characterized in that it comprises an outer ring magnetic sheet and a central magnet, and the outer ring magnetic sheet is provided with a hole adapted to the central magnet; the central magnet is fixed at the center. In the hole; the outer ring magnetic sheet includes at least one magnetically permeable layer, the magnetically permeable layer is a nanocrystalline strip, an amorphous strip, or a metal soft magnetic tape; the central magnetic conductor is a soft ferrite, Alternatively, the central magnet is a columnar body formed by laminating a plurality of magnetic powder core films.
2. The shielding sheet for a wireless charging module according to claim 1, wherein one end of the center magnet is located in the hole, and the other end of the center magnet is protruded from the outer ring magnetic sheet.
3. The shielding sheet for a wireless charging module according to claim 1 or 2, characterized in that the hole is a through hole adapted to the center magnet, and the top surface of the outer ring magnet sheet and the center magnet are The top faces are coplanar.
4. The shielding sheet for a wireless charging module according to claim 3, wherein an adhesive layer is provided on a top surface of the outer ring magnetic sheet, and a top surface of the central magnet is connected to the adhesive layer.
5. The shielding sheet for a wireless charging module according to claim 3, further comprising an outer ring magnet connected to the outer ring magnetic sheet, and the outer ring magnet is provided on the outer ring magnet for accommodating charging in the wireless charging module. The through hole of the coil, the central magnet is located in the through hole; the top surface of the outer ring magnet is coplanar with the top surface of the outer ring magnetic sheet, and the bottom surface of the outer ring magnet is protruding from A bottom surface of the outer ring magnetic sheet;

   The outer ring magnetizer is a soft ferrite, or the outer ring magnetizer is a columnar body formed by laminating a plurality of magnetic powder core films.
6. The shielding sheet for a wireless charging module according to claim 5, wherein the bottom surface of the outer ring magnet guide is coplanar with the bottom surface of the center magnet guide.
7. The wireless charging module includes a charging coil, further comprising a shielding sheet for a wireless charging module according to claim 1, wherein the hole is located in a hollow area of the charging coil.
8. The wireless charging module according to claim 7, wherein one end of the center magnet is located in the hole, and the other end of the center magnet is protruded from the outer ring magnetic sheet, and the charging is performed. The inner edge surface of the coil is in conflict with the outer edge surface of the center magnet.
9. The wireless charging module according to claim 8, further comprising an outer ring magnet connected to the outer ring magnetic sheet, the outer ring magnet is provided with a through hole, and the central guide magnet is located in the through hole. Inside, the outer edge surface of the charging coil is in conflict with the inner edge surface of the outer ring magnet;

   The outer ring magnetizer is a soft ferrite, or the outer ring magnetizer is a columnar body formed by stacking multiple magnetic powder core films, and two adjacent magnetic powder core films are connected.
10. The wireless charging module according to claim 9, characterized in that the top surface of the outer ring magnet is coplanar with the top surface of the center magnet, and the bottom surface of the outer ring magnet and the bottom surface of the center magnet are located The same side of the outer ring magnetic sheet.