MAGNETIC SHEET WITH STRIPE-ARRANGED MAGNETIC GRAINS, RFID MAGNETIC SHEET, MAGNETIC SHIELDING SHEET AND METHOD OF MANUFACTURING THE SAME

• US 20080070003A1
• Filed: 08/31/2007
• Published: 03/20/2008
• Est. Priority Date: 09/05/2006
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: HIRANO, Koichi, YAMASHITA, Yoshihisa, NAKATANI, Seiichi, ICHIRYU, Takashi
• Granted Patent: US 7,981,528 B2
• Time in Patent Office: Days
• US Class Current: 428/141
• CPC Class Codes: G06K 19/07749 the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card
• CPC Class Codes: G06K 19/07771 the record carrier comprising means for minimising adverse effects on the data communication capability of the record carrier, e.g. minimising Eddy currents induced in a proximate metal or otherwise electromagnetically interfering object
• CPC Class Codes: Y10T 428/24355 Continuous and nonuniform or irregular surface on layer or component [e.g., roofing, etc.]
• CPC Class Codes: Y10T 428/32 Composite [nonstructural laminate] of inorganic material having metal-compound-containing layer and having defined magnetic layer

Abstract

A water-repelling layer is formed on a resin film, and a stripe pattern region is formed so as to be positioned within a surface region of the water-repelling layer and so as to be relatively hydrophilic with respect to water repellency of the water-repelling layer. A magnetic stripe pattern is formed of needle-shaped magnetic grains oriented and aggregated in the stripe pattern region. The needle-shaped magnetic grains are arranged in a desirable state in a predetermined stripe pattern, with a high magnetic permeability and a magnetic sheet with stripe-arranged magnetic grains that is thin and flexible is obtained.

Claims

1. A magnetic sheet with stripe-arranged magnetic grains, comprising:

a resin film;

a water-repelling layer formed on the resin film;

a stripe pattern region that is arranged in a surface region of the water-repelling layer and is relatively hydrophilic with respect to water repellency of the water-repelling layer; and

a magnetic stripe pattern formed of needle-shaped magnetic grains oriented and aggregated in the stripe pattern region.

2. The magnetic sheet with stripe-arranged magnetic grains according to claim 1, wherein the stripe pattern region is a region where the water-repelling layer is absent to form a stripe state in a planar shape.

3. The magnetic sheet with stripe-arranged magnetic grains according to claim 1, wherein the needle-shaped magnetic grains are fixed in a state in which the needle-shaped magnetic grains are aggregated in the hydrophilic region by the effect of surface tension.

4. The magnetic sheet with stripe-arranged magnetic grains according to claim 1, wherein the hydrophilic region forming the stripe-shaped pattern region has a width narrower than a length of the length direction of the needle-shaped magnetic grains.

5. The magnetic sheet with stripe-arranged magnetic grains according to claim 1, wherein the needle-shaped magnetic grain is made from an anisotropic soft magnetic metal material.

6. The magnetic sheet with stripe-arranged magnetic grains according to claim 5, wherein the needle-shaped magnetic grain is made from an alloy including at least one element selected from the group consisting of Fe, Ni, and Co.

7. The magnetic sheet with stripe-arranged magnetic grains according to claim 1, wherein the magnetic stripe pattern comprises the needle-shaped magnetic grains and an organic binder.

8. The magnetic sheet with stripe-arranged magnetic grains according to claim 1, wherein the resin film is aramid resin or polyimide resin.

10. The RFID magnetic sheet according to claim 8, wherein a lattice pattern is formed with the magnetic stripe patterns extending along a first direction and the magnetic stripe patterns extending along a second direction, which are formed on the respective resin films of layers different from one another.

11. The RFID magnetic sheet according to claim 10, further comprising a resin film on which is formed a magnetic stripe pattern extending along a third direction that differs from the first and second directions.

9. An RFID (Radio Frequency Identification) magnetic sheet used in a RFID system, comprising:

a plurality of laminated resin films;

a water-repelling layer formed on each of the resin films;

a stripe pattern region that is arranged in a surface region of the water-repelling layer and is relatively hydrophilic with respect to water repellency of the water-repelling layer; and

a magnetic stripe pattern formed of needle-shaped magnetic grains oriented and aggregated in the stripe pattern region;

wherein a plurality of the magnetic stripe patterns are formed on each of the resin films so as to be isolated from one another; and

the magnetic stripe pattern on each of the resin films is arranged such that each pattern mutually intersects, in a planar shape, with the magnetic stripe pattern on the other resin film.

12. A non-contact type IC card, comprising:

the RFID magnetic sheet according to claim 9;

an antenna coil for RFID use, arranged adjacent to the RFID magnetic sheet; and

an IC chip connected to the antenna coil for RFID use.

13. A mobile communication apparatus, comprising:

the RFID magnetic sheet according to claim 9;

an antenna coil for RFID use, arranged adjacent to the RFID magnetic sheet; and

an IC chip connected to the antenna coil for RFID use.

14. An electromagnetic shielding sheet to be attached to a display, comprising:

a resin film;

a water-repelling layer formed on the resin film;

a stripe pattern region that is arranged in a surface region of the water-repelling layer and is relatively hydrophilic with respect to water repellency of the water-repelling layer; and

a magnetic stripe pattern formed of needle-shaped magnetic grains oriented and aggregated in the stripe pattern region,

wherein the stripe pattern region is a lattice-shaped pattern region formed into a lattice shape, and

a magnetic lattice-shaped pattern is formed of needle-shaped magnetic grains oriented and aggregated in the lattice-shaped pattern region.

15. The electromagnetic shielding sheet according to claim 14, wherein the needle-shaped magnetic grain is an iron metal magnetic grain or a ferrite magnetic grain.

16. The electromagnetic shielding sheet according to claim 14, wherein the resin film is made of translucent resin.

17. A flat panel display in which the electromagnetic shielding sheet according to claim 14 is attached to the front face of a display panel.

18. The flat panel display according to claim 17, wherein the display panel is a plasma display panel.

19. A method of manufacturing a magnetic sheet with stripe-arranged magnetic grains, comprising:

a step (a) of forming, on a resin film, a water-repelling layer, and a stripe pattern region that is positioned within a surface region of the water-repelling layer and is relatively hydrophilic with respect to water repellency of the water-repelling layer; and

a step (b) of providing a solution containing the needle-shaped magnetic grains to the stripe pattern region to form a magnetic stripe pattern of needle-shaped magnetic grains oriented and aggregated in the stripe pattern region.

20. The method of manufacturing a magnetic sheet with stripe-arranged magnetic grains according to claim 19, wherein the stripe pattern region is a region where the resin film is exposed so as to be surrounded by the water-repelling layer.

21. The method of manufacturing a magnetic sheet with stripe-arranged magnetic grains according to claim 19, wherein the step (a) includes

a step of forming, on the resin film, a water-repelling layer having a water-repellent property against the solution in the step (b);

and

a step of forming a hydrophilic region by exposing the water-repelling layer by using a mask defining the stripe pattern region.

22. The method of manufacturing a magnetic sheet with stripe-arranged magnetic grains according to claim 19, wherein the step (a) includes a step of forming a hydrophilic region by exposing, using a mask defining the stripe pattern region, a film having a surface that is changeable to be hydrophilic with an exposure.

23. The method of manufacturing a magnetic sheet with stripe-arranged magnetic grains according to claim 19, wherein the step (b) includes

a step of providing a solution on top of the resin film on which the stripe pattern region has been formed;

and

a step of introducing the needle-shaped magnetic grains to the solution provided on the resin film.

24. The method of manufacturing a magnetic sheet with stripe-arranged magnetic grains according to claim 19, wherein the step (b) includes

a step of dispersing the needle-shaped magnetic grains in the solution;

and

a step of applying, on the resin film, the solution in which the needle-shaped magnetic grains have been dispersed.

25. The method of manufacturing a magnetic sheet with stripe-arranged magnetic grains according to claim 19, wherein in the step (b), the needle-shaped magnetic grains are arranged in the stripe pattern region by surface tension of the solution.

26. The method of manufacturing a magnetic sheet with stripe-arranged magnetic grains according to claim 19, comprising a step of transferring to another film the magnetic stripe pattern after the step (b).

27. The method of manufacturing a magnetic sheet with stripe-arranged magnetic grains according to claim 19, wherein the steps (a) and (b) are successively executed in a roll to roll method.

28. A method of manufacturing a RFID magnetic sheet, comprising:

a step (a) of forming, on a resin film, a water-repelling layer and a stripe pattern region that is positioned within a surface region of the water-repelling layer and is relatively hydrophilic with respect to water repellency of the water-repelling layer;

a step (b) of providing a solution containing needle-shaped magnetic grains to the stripe pattern region formed on the resin film to form a magnetic stripe pattern by orienting and aggregating the needle-shaped magnetic grains in the stripe pattern region; and

a step (c) of laminating the resin film on which the magnetic stripe pattern has been formed,

wherein in the step (a), a plurality of the stripe pattern regions are formed such that each is isolated from one another; and

in the step (c), the magnetic stripe pattern on each of the resin films is arranged such that each pattern mutually intersects, in a planner shape, with the magnetic stripe pattern on the other resin films.

29. The method of manufacturing a RFID magnetic sheet according to claim 28, wherein in a planar shape of a laminated body of the resin films, the laminated body is formed such that a lattice pattern is formed with the magnetic stripe pattern extending along a first direction and the magnetic stripe pattern extending along a second direction.

30. A method of manufacturing an electromagnetic shielding sheet, comprising:

a step (a) of forming, on a resin film, a water-repelling layer and a stripe pattern region that is positioned within a surface region of the water-repelling layer and is relatively hydrophilic with respect to water repellency of the water-repelling layer; and

a step (b) of providing a solution containing needle-shaped magnetic grains to the stripe pattern region formed on the resin film to form a magnetic stripe pattern by orienting and aggregating the needle-shaped magnetic grains in the stripe pattern region,

wherein in the step (a), the stripe pattern region is formed into a lattice shape, and

in the step (b), the magnetic lattice-shaped pattern is formed by orienting and aggregating the needle-shaped magnetic grains in the lattice-shaped stripe pattern region.