Magnetic field shielding sheet for a wireless charger, method for manufacturing same, and receiving apparatus for a wireless charger using the sheet
Provided are a magnetic field shield sheet for a wireless charger, a method of manufacturing the sheet, and a receiver for the wireless charger by using the sheet. The sheet includes at least one layer thin magnetic sheet made of an amorphous ribbon separated into a plurality of fine pieces; a protective film that is adhered on one surface of the thin magnetic sheet via a first adhesive layer provided on one side of the protective film; and a double-sided tape that is adhered on the other surface of the thin magnetic sheet via a second adhesive layer provided on one side of the double-sided adhesive tape, wherein gaps among the plurality of fine pieces are filled by some parts of the first and second adhesive layers, to thereby isolate the plurality of fine pieces.
1. A magnetic field shield sheet for a wireless charger, the magnetic field shield sheet comprising:
a magnetic sheet separated into a plurality of pieces by a flake-treatment process; and
an adhesive member adhered on one surface of the magnetic sheet such that the adhesive member is adhered to the plurality of pieces, at least parts of the pieces being mutually isolated, and at least parts of gaps among the plurality of pieces being filled by an adhesive of the adhesive member;
wherein an inductance of the magnetic sheet is in the range of 13 μH to 19 μH.
2. The magnetic field shield sheet for a wireless charger of claim 1 , wherein the magnetic field shield sheet is applied to a reception device of a wireless charger, and wherein the magnetic sheet comprises 2 to 4 layers of laminated sheets made of a Fe-based amorphous alloy or a nanocrystalline alloy, and an adhesive layer is inserted among the laminated sheets.
3. A reception device for a wireless charger that charges a secondary battery from a transmission device for the wireless charger, the reception device comprising:
a coil unit that receives a wireless signal transmitted from the transmission device; and
a magnetic field shield sheet that is disposed between the coil unit and the secondary battery,
wherein the magnetic field shield sheet comprises:
a magnetic sheet separated into a plurality of pieces by a flake-treatment process; and
an adhesive member adhered on one surface of the magnetic sheet such that the adhesive member is adhered to the plurality of pieces, at least parts of the pieces being mutually isolated, and at least parts of gaps among the plurality of pieces being filled by an adhesive of the adhesive member;
wherein an inductance of the magnetic sheet is in the range of 13 μH to 19 μH.
4. The reception device for a wireless charger of claim 3 , wherein the coil unit and an antenna coil for near field communications (NFC) are formed on a single substrate.
5. A method of manufacturing a magnetic field shield sheet for a wireless charger, the method comprising the steps of:
adhering a protective film and a double-sided tape having a release film formed on an exposed surface of the double-sided tape, on both sides of a magnetic sheet comprising a plurality of layers of a thermally treated ribbon sheet, to thereby form a laminate sheet;
performing a flake treatment process of the laminate sheet to thus separate the magnetic sheet into a plurality of pieces; and
laminating the flake treated laminate sheet, to thus fill some parts of a first adhesive layer provided on the protective film and a second adhesive layers provided on the double-sided tape into at least parts of gaps among the plurality of pieces, together with flattening and thinning of the laminate sheet.
6. The method of manufacturing the magnetic field shield sheet for a wireless charger of claim 5 , wherein an adhesive layer is disposed between the plurality of layers of the thermally treated ribbon sheet.
7. The method of manufacturing the magnetic field shield sheet for a wireless charger of claim 5 , wherein the method further comprises the step of thermally treating the ribbon sheet before forming the laminate sheet.