Magnetic field shielding sheet for digitizer, manufacturing method thereof, and portable terminal device using same

• US 9,507,390 B2
• Filed: 02/04/2013
• Issued: 11/29/2016
• Est. Priority Date: 02/03/2012
• Status: Active Grant

• Current Assignee: Amosense Co., Ltd.
• Original Assignee: Amosense Co., Ltd.
• Inventors: Jang, Kil Jae, Lee, Dong Hoon, Lee, Dong Kun
• Primary Examiner(s): Thompson, Timothy
• Assistant Examiner(s): EGOAVIL, GUILLERMO J
• Application Number:
  US14/371,787
• Publication Number:
  US 20140362505A1
• Time in Patent Office: 1,394 Days
• Field of Search: 156/62.2, 174/377, 252/62.56, 252/518.1, 361/679.4, 428/328, 428/704, 428/333, 428/699, 428/900, 524/435, 977/838
• US Class Current: 1/1
• CPC Class Codes: B82Y 25/00 Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
• CPC Class Codes: G06F 1/1684 Constructional details or arrangements related to integrated I/O peripherals not covered by groups G06F1/1635 - G06F1/1675
• CPC Class Codes: G06F 1/182 with special features, e.g. for use in industrial environments; grounding or shielding against radio frequency interference [RFI] or electromagnetical interference [EMI]
• CPC Class Codes: H01F 10/08 characterised by magnetic layers H01F10/32 takes precedence ; applying thin magnetic films to substrates H01F41/14
• CPC Class Codes: H05K 9/0075 Magnetic shielding materials
• CPC Class Codes: Y10S 977/838 Magnetic property of nanomaterial

Abstract

Provided is a magnetic field shield sheet for a digitizer, which blocks an effect of a magnetic field generated from various components of a main body of the portable terminal device and at the same time improves the sensitivity of an electronic pen when a digitizer feature is implemented in the portable terminal device, while minimizing an influence upon a geomagnetic sensor. The magnetic field shield sheet includes: at least one layer thin magnetic sheet made of a nanocrystalline alloy and flake-treated so as to be 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.

Claims

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

at least one layer thin magnetic sheet made of a nanocrystalline alloy and flake-treated so as to be 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 the thin magnetic sheet has a value of a saturation field (Hs) higher than a geomagnetic field.

2. The magnetic field shield sheet according to claim 1, wherein the thin magnetic sheet is obtained by heat treating an amorphous ribbon at a temperature of 300°

C. to 700°

C. and a B—

H loop that is a curve between a magnetic flux density and a magnetic field intensity of the thin magnetic sheet is changed in an initial magnetization curve.

3. The magnetic field shield sheet according to claim 2, wherein the amorphous ribbon is heat-treated in a temperature range of 600°

C. to 700°

C., and has an inductance value in the range of 13 to 21 μ

H.

8. The magnetic field shield sheet according to claim 1, wherein the fine pieces are formed of several tens of micrometers (μ

m) to 3 mm in size.

10. The magnetic field shield sheet according to claim 3, wherein the inductance value is in the range of 16.5 to 17.5 μ

H.

4. A magnetic field shield sheet for a digitizer, the magnetic field shield sheet comprising:

at least one layer thin magnetic sheet made of a nanocrystalline alloy and flake-treated so as to be 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 the thin magnetic sheet comprises;

nanocrystalline ribbon sheets which are stacked with a multi-layer structure; and

double-sided tapes inserted between the adjacent two nanocrystalline ribbon sheets, and

wherein the nanocrystalline ribbon sheet of each layer is made of a pair of nanocrystalline ribbon sheets that are connected in a butting manner, and two pair of adjacent nanocrystalline ribbon sheets are disposed in a direction which is perpendicular to each other.

5. A magnetic field shield sheet for a digitizer, the magnetic field shield sheet comprising:

at least one layer thin magnetic sheet made of a nanocrystalline alloy and flake-treated so as to be 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;

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; and

an auxiliary magnetic sheet that is overlapped in an annular form on one side or an outer periphery of the thin magnetic sheet, and that has a magnetic permeability lower or higher than the thin magnetic sheet.

6. A magnetic field shield sheet for a digitizer, the magnetic field shield sheet comprising:

at least one layer thin magnetic sheet made of a nanocrystalline alloy and flake-treated so as to be 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 the thin magnetic sheet comprises;

a nanocrystalline ribbon sheet;

a polymer sheet that is stacked on the nanocrystalline ribbon sheet and has a lower permeability than the nanocrystalline ribbon sheet; and

an adhesive layer that mutually bonds the nanocrystalline ribbon sheet and the polymer sheet and fills gaps between the fine pieces.

7. A magnetic field shield sheet for a digitizer, the magnetic field shield sheet comprising:

at least one layer thin magnetic sheet made of a nanocrystalline alloy and flake-treated so as to be 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 some of the first adhesive layer and the second adhesive layer are filled into the gaps between the fine pieces.

9. A magnetic field shield sheet for a digitizer, the magnetic field shield sheet comprising:

at least one layer thin magnetic sheet made of a nanocrystalline alloy and flake-treated so as to be 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;

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; and

a conductive sheet that is formed of a thin plate on an outer surface of the protective film to thus shield an electromagnetic wave.