Antenna core and method of manufacturing the same, and antenna and detection system using the same

1. An antenna core comprising a laminate of a plurality of Co-based amorphous magnetic alloy thin strips in which a length ratio of a long axis to a short axis is greater than 1,

wherein 60% or more of the plural Co-based amorphous magnetic alloy thin strips in terms of the number of the thin strips as percentage each have a line-shaped mark formed along the long axis on at least one surface thereof.

2. The antenna core according to claim 1 ,

wherein the Co-based amorphous magnetic alloy thin strips located in outermost layers on both sides of the laminate each have the line-shaped mark.

3. The antenna core according to claim 1 ,

wherein the length ratio of the long axis to the short axis of the Co-based amorphous magnetic alloy thin strips is in a range of not less than 2 nor more than 40.

4. The antenna core according to claim 1 ,

wherein t1/t2 ratio of the Co-based amorphous magnetic alloy thin strips is in a range of not less than 1 nor more than 1.4, where t1 is a largest thickness of each of the Co-based amorphous magnetic alloy thin strips, and t2 is an average thickness of each of the Co-based amorphous magnetic alloy thin strips.

5. The antenna core according to claim 1 ,

wherein the Co-based amorphous magnetic alloy thin strips have an H-shape.

6. The antenna core according to claim 1 ,

wherein the Co-based amorphous magnetic alloy thin strips have a composition expressed by

a general formula: Co a D b M c Si d B e

where, D is at least one element selected from Fe and Ni, M is at least one element selected from Ti, V, Cr, Mn, Cu, Zr, Nb, Mo, Ta, and W, and a, b, c, d and e are a+b+c+d+e=100 atomic %, and 1≦b≦10, 0.3≦c≦6.5, 5≦d≦12, 1≦e≦8.

7. The antenna core according to claim 1 ,

wherein the line-shaped mark is a mark on a roll surface formed when the Co-based amorphous magnetic alloy thin strips are fabricated by a roll rapid cooling.

8. The antenna core according to claim 1 ,

wherein the number of the stacked Co-based amorphous magnetic alloy thin strips is in a range of not less than 10 nor more than 50.

9. The antenna core according to claim 1 ,

wherein the laminate has an insulating resin layer interposed between at least part of the Co-based amorphous magnetic alloy thin strips.

10. The antenna core according to claim 1 ,

wherein a maximum magnetic flux density of the antenna core is in a range of not less than 0.35 T nor more than 1.2 T.

11. A method of manufacturing an antenna core, comprising:

fabricating a long Co-based amorphous magnetic alloy thin strip by a roll rapid cooling;

fabricating a plurality of Co-based amorphous magnetic alloy thin strips, in which a length ratio of a long axis to a short axis is greater than 1, by cutting or press-working the long Co-based amorphous magnetic alloy thin strip so as to make a length direction of the long Co-based amorphous magnetic alloy thin strip become the long-axes of the plural Co-based amorphous magnetic alloy thin strips;

forming a laminate by stacking the plural Co-based amorphous magnetic alloy thin strips; and

impregnating with an insulating resin between the Co-based amorphous magnetic alloy thin strips in the laminate.

12. The manufacturing method according to claim 11 , further comprising:

heat-treating the laminate in which the insulating resin is impregnated.

13. The manufacturing method according to claim 11 ,

wherein the Co-based amorphous magnetic alloy thin strips have a line-shaped mark formed along the long axis on at least one surface thereof.

14. A method of manufacturing an antenna core, comprising:

fabricating a long Co-based amorphous magnetic alloy thin strip by a roll rapid cooling;

covering at least one surface of the long Co-based amorphous magnetic alloy thin strip with an insulating resin;

fabricating a plurality of Co-based amorphous magnetic alloy thin strips, in which a length ratio of a long axis to a short axis is greater than 1, by cutting or press-working the long Co-based amorphous magnetic alloy thin strip so as to make a length direction of the long Co-based amorphous magnetic alloy thin strip become the long-axes of the plural Co-based amorphous magnetic alloy thin strips; and

forming a laminate by stacking the plural Co-based amorphous magnetic alloy thin strips.

15. The manufacturing method according to claim 14 , further comprising:

heat-treating the laminate.

16. The manufacturing method according to claim 14 ,

wherein the Co-based amorphous magnetic alloy thin strips have a line-shaped mark formed along the long axis on at least one surface thereof.

17. An antenna, comprising:

the antenna core according to claim 1 ; and

a winding wound around the antenna core along the long axis.