Magnetic sheet and non-contact power receiving device, electronic apparatus and non-contact charging system using the same

1. A non-contact power receiving device magnetic sheet comprising a stack of magnetic thin strips and resin film parts which are stacked in a thickness direction of the non-contact power receiving device magnetic sheet;

wherein the stack includes the magnetic thin strips whose number is from 6 to 25 and the resin film parts alternately stacked with the magnetic thin strips, and the magnetic thin strips are provided with cutout portions each having a width of 1 mm or less;

wherein a ratio (B/A) of a total length B of the cutout portions to a total outer peripheral length A of the magnetic thin strip is in a range of from 6.8 to 25, wherein the total outer peripheral length A is a total length of an outer peripheral area of the magnetic thin strip arranged on one of the resin film parts, and the total length B of the cutout portions is a total length of the cutout portions provided to the magnetic thin strip;

wherein each of the cutout portions is a gap shaped cut-out portion separating one at the magnetic thin strips or is a slit-shaped cutout portion formed in one at the magnetic thin strips, and each of the cutout portions has a liner shape, a curved shape, a zigzag shape, or a cross shape; and

wherein the resin film parts entirely cover peripheral surfaces of the magnetic thin strips so that the magnetic thin strips are not exposed.

2. The non-contact power receiving device magnetic sheet according to claim 1 ,

wherein the stack includes, as the magnetic thin strip, one or more of amorphous alloy thin strip having a composition represented by a general formula:

Fe 100-a-b-c M a X b T c

 wherein M is at least one element selected from the group consisting of Ni and Co, T is at least one element selected from the group consisting of Mn, Cr, Ti, Zr, Hf, Mo, V, Nb, W, Ta, Cu, Sn and rare-earth elements, X is at least one element selected from the group consisting of B, Si, C and P, a is a number satisfying 0≤a≤25 atom %, b is a number satisfying 10≤b≤35 atom %, and c is a number satisfying 0≤c≤5 atom %.

3. The non-contact power receiving device magnetic sheet according to claim 1 ,

wherein the stack includes one or more of the magnetic thin strip having a thickness in a range of from 5 to 30 μm.

4. The non-contact power receiving device magnetic sheet according to claim 1 ,

wherein the stack includes one or more of the magnetic thin strip which is not broken when being subjected to 180° adhesion bending.

5. The non-contact power receiving device magnetic sheet according to claim 1 ,

wherein the stack includes one or more of the magnetic thin strip having a saturation magnetostriction constant of 15 ppm or more.

6. The non-contact power receiving device magnetic sheet according to claim 1 ,

wherein the stack includes one or more of the magnetic thin strip having a saturation magnetic flux density in a range of from 1.2 to 2.1 T.

7. A non-contact power receiving device, comprising:

a power receiving coil having a spiral coil;

a rectifier rectifying an alternating voltage generated in the power receiving coil;

a secondary battery to which a direct-current voltage rectified in the rectifier is charged; and

the non-contact power receiving device magnetic sheet according to claim 1 arranged in at least one of a position between the spiral coil and the secondary battery and a position between the spiral coil and the rectifier.

8. An electronic apparatus, comprising:

a non-contact power receiving device including a power receiving coil having a spiral coil, a rectifier rectifying an alternating voltage generated in the power receiving coil, and a secondary battery to which a direct-current voltage rectified in the rectifier is charged;

an electronic apparatus main body including an electronic device supplied with the direct-current voltage from the secondary battery for operation, and a circuit board on which the electronic device is mounted; and

the non-contact power receiving device magnetic sheet according to claim 1 arranged in at least one of a position between the spiral coil and the secondary battery, a position between the spiral coil and the rectifier, a position between the spiral coil and the electronic device, and a position between the spiral coil and the circuit board.

9. A non-contact charging system, comprising:

the electronic apparatus according to claim 8 ; and

a power feeding device including a power feeding coil arranged in a non-contact manner with respect to the power receiving coil of the electronic apparatus, a power supply applying an alternating voltage to the power feeding coil, and a magnet for positioning,

wherein the positioning of the electronic apparatus is conducted using the magnet, and then a magnetic flux generated in the power feeding coil is transmitted to the power receiving coil to transmit power in a non-contact manner.

10. The non-contact charging system according to claim 9 , wherein the magnet is a Nd—Fe—B-based magnet.

11. The non-contact charging system according to claim 9 , wherein the non-contact power receiving device magnetic sheet is arranged as at least one of a magnetic shield and an inductor.

12. The magnetic non-contact power receiving device sheet according to claim 1 ,

wherein the magnetic thin strips which are adjacent through the cutout portion have a contact region.

13. The magnetic non-contact power receiving device sheet according to claim 1 ,

wherein the stacked number of the magnetic thin strips is from 10 to 25.

14. The magnetic non-contact power receiving device sheet according to claim 1 ,

wherein the ratio (B/A) is in a range of from 6.8 to 16.8.