MAGNETIC FIELD SHIELDING SHEET FOR A WIRELESS CHARGER, METHOD FOR MANUFACTURING SAME, AND RECEIVING APPARATUS FOR A WIRELESS CHARGER USING THE SHEET

• US 20150123604A1
• Filed: 12/21/2012
• Published: 05/07/2015
• Est. Priority Date: 12/21/2011
• Status: Active Grant

• Current Assignee: Amosense Co., Ltd.
• Original Assignee: Amosense Co., Ltd.
• Inventors: Lee, Dong Hoon, Jang, Kil Jae
• Granted Patent: US 9,252,611 B2
• Time in Patent Office: Days
• US Class Current: 320/108
• CPC Class Codes: B32B 37/12 characterised by using adhesives
• CPC Class Codes: B32B 37/18 involving the assembly of discrete sheets or panels only
• CPC Class Codes: B32B 38/0004 Cutting, tearing or severing, e.g. bursting; Cutter details cutting in general B26D; laminating combined with punching or perforating B32B38/04; removing all or part of the layers B32B38/10; cutting in combination with laying up and registration B32B38/185 takes precedence
• CPC Class Codes: H01F 27/36 Electric or magnetic shields or screens movable for varying inductance H01F21/10
• CPC Class Codes: H01F 27/366 made of ferromagnetic material
• CPC Class Codes: H01F 38/14 Inductive couplings for wireless supply or distribution of electric power using inductive coupling H02J50/10
• CPC Class Codes: H01Q 7/06 with core of ferromagnetic material H01Q7/02 takes precedence
• CPC Class Codes: H01Q 7/08 Ferrite rod or like elongated core
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/70 involving the reduction of electric, magnetic or electromagnetic leakage fields
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H02J 7/0042 characterised by the mechanical construction
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer
• CPC Class Codes: H05K 9/0075 Magnetic shielding materials
• CPC Class Codes: H05K 9/0081 Electromagnetic shielding materials, e.g. EMI, RFI shielding H05K9/0003 takes precedence
• CPC Class Codes: H05K 9/0088 comprising a plurality of shielding layers; combining different shielding material structure
• CPC Class Codes: Y10T 156/10 Methods of surface bonding and/or assembly therefor
• CPC Class Codes: Y10T 428/249955 Void-containing component partially impregnated with adjacent component
• CPC Class Codes: Y10T 428/249956 Void-containing component is inorganic
• CPC Class Codes: Y10T 428/25 Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles
• CPC Class Codes: Y10T 428/2848 : Three or more layers
• CPC Class Codes: Y10T 428/32 : Composite [nonstructural laminate] of inorganic material having metal-compound-containing layer and having defined magnetic layer

Abstract

Provided are a magnetic field shield sheet for a wireless charger, which blocks an effect of an alternating-current magnetic field generated when a charger function for a portable mobile terminal device is implemented in a non-contact wireless manner on a main body of the portable mobile terminal device and exhibits excellent electric power transmission efficiency, 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.

Claims

1. A magnetic field shield sheet for a wireless charger, the magnetic field shield sheet comprising:

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.

2. The magnetic field shield sheet for a wireless charger of claim 1, wherein the thin magnetic sheet comprises:

a first magnetic sheet with a first permeability;

a second magnetic sheet with a second permeability lower than the first permeability, in which the second magnetic sheet is laminated on the first magnetic sheet; and

an adhesive layer that mutually adheres the first and second magnetic sheets and fills the gaps among the plurality of fine pieces.

3. The magnetic field shield sheet for a wireless charger of claim 2, wherein the first magnetic sheet is any one selected from an amorphous sheet, a ferrite sheet, a permalloy sheet, a MPP (Moly Permalloy Powder) sheet, and the second magnetic sheet is a polymer made of a magnetic powder and a resin.

4. The magnetic field shield sheet for a wireless charger of claim 2, wherein the first magnetic sheet is made of an amorphous sheet, and the second magnetic sheet is made of a ferrite sheet.

5. 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 having a permanent magnet in a transmission device, and wherein the thin magnetic sheet is made of a Fe-based amorphous alloy or nanocrystalline alloy, and comprises 2 to 12 layers of laminated amorphous ribbons, and adhesive layers inserted among the laminated amorphous ribbons.

6. 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 having no permanent magnet in a transmission device, and wherein the thin magnetic sheet comprises 1 to 4 layers of laminated amorphous ribbons, and adhesive layers inserted among the laminated amorphous ribbons.

7. The magnetic field shield sheet for a wireless charger of claim 1, wherein the double-sided tape comprises:

a base member;

a second adhesive layer formed on one surface of the base member and adhered to the other surface of the thin magnetic sheet; and

a third adhesive layer formed on the other surface of the base member, and wherein the second adhesive layer is filled in the gaps among the plurality of fine pieces and integrated with the first adhesive layer.

8. The magnetic field shield sheet for a wireless charger of claim 1, wherein the magnetic field shield sheet is formed of a shape corresponding to a secondary coil provided on the reception device of the wireless charger.

9. The magnetic field shield sheet for a wireless charger of claim 1, wherein the thin magnetic sheet is made of a Fe-based amorphous alloy, and is thermally treated for 30 minutes to 2 hours at a temperature of 300°

C. to 600°

C.

10. The magnetic field shield sheet for a wireless charger of claim 1, wherein the thin magnetic sheet is made of a nanocrystalline alloy, and is thermally treated for 30 minutes to 2 hours at a temperature of 600°

C. to 700°

C.

11. The magnetic field shield sheet for a wireless charger of claim 1, wherein the plurality of fine pieces are formed of several tens of μ

m to 3 mm in size.

12. 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 formed of a release film on an exposed surface of the double-sided tape, on both sides of at least one layer thin magnetic sheet made of an amorphous ribbon, to thereby form a laminate sheet;

performing a flake treatment process of the laminate sheet to thus separate the thin magnetic sheet into a plurality of fine pieces; and

laminating the flake treated laminate sheet, to thus fill some parts of first and second adhesive layers provided in the protective film and the double-sided tape into gaps among the 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, together with flattening and thinning of the laminate sheet, and to thereby isolate the plurality of fine pieces.

13. The method of manufacturing the magnetic field shield sheet for a wireless charger of claim 12, further comprising the step of thermally treating the amorphous ribbon before forming the laminate sheet.

14. The method of manufacturing the magnetic field shield sheet for a wireless charger of claim 12, wherein the first and second adhesive layers are formed to have a thickness greater than 50% compared to the thickness of the amorphous ribbon.

15. The method of manufacturing the magnetic field shield sheet for a wireless charger of claim 12, wherein the thin magnetic sheet is a hybrid magnetic sheet that is obtained by laminating a first magnetic sheet of a first permeability and a second magnetic sheet of a second permeability lower than the first permeability, through an adhesive layer.

16. The method of manufacturing the magnetic field shield sheet for a wireless charger of claim 12, wherein the first magnetic sheet is made of an amorphous sheet, and the second magnetic sheet is made of a ferrite sheet or polymer sheet.

17. A reception device for a wireless charger that charges a secondary battery by an electromagnetic induction method from a transmission device for the wireless charger, the reception device comprising:

a secondary coil that receives a wireless high frequency signal transmitted by the electromagnetic induction method from the transmission device; and

a magnetic field shield sheet that is disposed between the secondary coil and the secondary battery, and that shields a magnetic field generated by the wireless high frequency signal and simultaneously induces the secondary coil to absorb the wireless high frequency signal necessary to perform a wireless charging function,

wherein the magnetic field shield sheet comprises;

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.

18. The reception device for a wireless charger of claim 17, wherein the secondary coil and an antenna coil for near field communications (NFC) are simultaneously formed on a single insulating substrate.

19. The reception device for a wireless charger of claim 18, wherein the thin magnetic sheet of the magnetic field shield sheet is a sheet in which an amorphous ribbon sheet, a ferrite sheet, or a polymer sheet is bonded through an adhesive layer.

20. The reception device for a wireless charger of claim 18, wherein the thin magnetic sheet of the magnetic field shield sheet comprises:

an amorphous ribbon sheet that is disposed in a certain area at a central portion of the thin magnetic sheet; and

an annular ferrite loop that surrounds the amorphous ribbon sheet in the outside of the amorphous ribbon sheet.