JPH0234902A - Thin film electromagnetic transformer - Google Patents

Abstract

PURPOSE:To enable signals to be exchanged efficiently by forming a recess at which the end face of a magnetic substance layer is exposed in a position corresponding to the central part of each coil of the magnetic substance layer. CONSTITUTION:Recesses 15 and 15 are formed respectively at the central parts of individual coils 13 and 14, and since their side faces are the end faces of a magnetic film 12, magnetic fluxes flow out easily from the inner end faces of the recesses 15 and 15. In this case, if a magnetic pole arises in the direction along the face of the magnetic substance, the reverse magnetic field is much smaller as compared with the case that the magnetic pole arises in the direction crossing the face of the magnetic substance at right angles; therefore, the magnetic flux flows favorably. Accordingly, it can let flow the magnetic flux capable of obtaining signal strength sufficient for lead/light operation by a magnetic head. Hereby, the exchange of signals can be done efficiently.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a thin film electromagnetic transducer used for example in an IC card.

(Prior Art) IC cards incorporating semiconductor memory elements have dramatically increased storage capacity compared to conventional magnetic cards, and are about to be applied to an unprecedentedly wide range of applications.

By the way, it is generally considered that the connection for exchanging signals between such an IC card and the read/write device is made mechanically via a connector, but it is not possible to Depending on the usage environment, reliability problems may occur.

For this reason, it is conceivable to use a υ~ read/write device in a magnetic card system to once convert an electrical signal into a magnetic signal, and then transmit the signal in a non-contact manner using a magnetic head.

FIG. 5 is a perspective view showing an example of a thin film electromagnetic transducer used in the above-mentioned IC card.

In the figure, 1 indicates a substrate. On board 1,
A magnetic thin film 2 is formed. On the magnetic thin film 2, a pair of coils 3a are connected in series.

3b is formed. These coils 3a, 3b are
The coils 3a and 3b are provided in a spiral shape, and the magnetic fluxes generated in the coils 3a and 3b are in opposite directions with respect to the direction perpendicular to the surface of the substrate 1.

FIG. 6 shows the relationship between the thin film electromagnetic transducer of this IC card and the magnetic head on the read/write device side.

As shown in the figure, the change in magnetic flux generated in each coil 3a, 3b is transmitted through the magnetic head's coil (
(not shown), and a signal is transmitted.

By the way, in the thin film electromagnetic transducer described above, each coil 3a
, 3b, it is necessary to flow a magnetic flux almost perpendicularly to the magnetic thin film 2, but generally magnetizing a magnetic material in a direction perpendicular to the plate surface causes a large reaction when a magnetic pole is generated on the plate surface. This was extremely difficult because it generated a magnetic field. Therefore, there is a problem in that it is difficult to obtain sufficient signal strength for read/write operations by the magnetic head.

(Problems to be Solved by the Invention) As mentioned above, in the conventional thin film electromagnetic converter, the coil 3
There was a problem in that only a part of the magnetic flux generated from a and 3b acts on the magnetic head, resulting in poor signal exchange efficiency.

Therefore, an object of the present invention is to provide a thin film electromagnetic transducer that can efficiently exchange signals.

[Structure of the Invention] (Means for Solving the Problems) The present invention includes a pair of electrically connected coils disposed on a magnetic layer in an annular and spiral shape, and magnetic flux generated from these coils is applied to the magnetic layer. In the thin film electromagnetic transducer, the directions are opposite to each other with respect to the direction perpendicular to the surface of the body layer, at least an end face of the magnetic layer is located at a position corresponding to the center portion of each of the coils of the magnetic layer. An exposed recess is formed.

(Function) In this invention, since the magnetic flux generated from the coil is configured to flow from the end face of one recess of the magnetic layer to the end face of the other recess through the magnetic layer, the core on the reading side The resulting magnetic flux provides sufficient signal strength. Therefore, signals can be exchanged efficiently.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing a thin film electromagnetic transducer according to an embodiment of the present invention, and FIG. 2 is a partially sectional side view showing the open collar of the thin film electromagnetic transducer of FIG. 1 and a magnetic head on the read/write device side. It is a diagram.

In these figures, 11 indicates a substrate.

A magnetic thin film 12 is formed on this substrate 11 by, for example, sputtering. A pair of coils 13 and 14 are formed on the magnetic thin film 12. These pair of coils 13 and 14 are electrically connected in series and each has a rectangular and spiral shape. The magnetic fluxes generated in the coils 13 and 14 are arranged in opposite directions with respect to the direction perpendicular to the surface of the substrate 11.

Further, on the magnetic thin film 12, square recesses 15.
15 is formed. The inner surface 15a1 of the recess 15, that is, the end surface of the magnetic thin film 12 is exposed. In addition, 16
．． 16 is a bonding pad formed at the end of the coil 13, 14.

FIG. 2 is a diagram showing the relationship between the thin film electromagnetic transducer described above and the magnetic head on the read/write device side.

As shown in the figure, the magnetic flux generated in each coil 13.14 flows through a magnetic circuit formed between the core 17 of the magnetic head and the magnetic thin film 12 below the coils 13.14. At this time, the magnetic flux flows through the magnetic thin film 12 from the inner surface 15a of the recess 15 formed at the center of one coil 13, and from the inner surface 15a of the recess 15 formed at the center of the other coil 14, the magnetic flux flows through the magnetic head. It flows to the core 17 side. This is then perceived as a change in potential in a coil (not shown) of the magnetic head via the core 17 of the magnetic head, and a signal is transmitted.

By the way, in the thin film electromagnetic transducer described above, each coil 13
．． Recesses 15 and 15 are formed in the center of each magnetic thin film 13, and the inner surfaces of the recesses 15 and 15 are the end surfaces of the magnetic thin film 12.
Magnetic flux easily flows out from the inner surface of the aforementioned recess 15.15. In this case, when magnetic poles are generated in a direction along the surface of the magnetic material, the demagnetizing field is much smaller than when magnetic poles are generated in a direction perpendicular to the surface of the magnetic material, so that magnetic flux flows well.

Therefore, in this embodiment, magnetic flux that can obtain sufficient signal strength for read/write operations by the magnetic head can flow from the thin film electromagnetic transducer to the magnetic head side.

In addition, in the embodiment described above, each coil 1 of the magnetic thin film 12
Although angular recesses 15.15 are formed at the central positions of 3.14, circular recesses 25.25 may be formed as shown in FIG. In FIG. 3, parts common to those in FIG. 1 are given the same reference numerals and redundant explanations will be omitted.

Further, in each of the embodiments described above, the magnetic thin film 1 is provided on the substrate 11.
2 has been described, however, as shown in FIG. 4, a recess 35 that does not penetrate through the magnetic substrate 21 made of a magnetic material may be provided.

Note that in FIG. 4, parts common to those in FIG. 1 are given the same reference numerals and redundant explanations will be omitted.

Further, in each of the above embodiments, rectangular spiral coils 13 and 14 are provided, but circular spiral coils may also be provided.

[Effects of the Invention] As explained above, in the thin film electromagnetic transducer of the present invention, a recess is formed in the magnetic layer at a position corresponding to the center portion of each coil, so that the end face of the recess in the magnetic layer is exposed. Therefore, signals can be exchanged efficiently.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a thin film electromagnetic transducer according to an embodiment of the present invention, and FIG. 2 is a partially sectional side view showing the relationship between the thin film electromagnetic transducer of FIG. 1 and a magnetic head on the read/write device side. figure,
FIG. 3 is a perspective view showing a thin film electromagnetic transducer according to another embodiment of the invention, FIG. 4 is a perspective view showing a thin film electromagnetic transducer according to still another embodiment of the invention, and FIG. 5 is a perspective view showing a thin film electromagnetic transducer according to another embodiment of the invention. FIG. 6 is a perspective view showing an electromagnetic transducer, and FIG. 6 is a partial side view showing the relationship between the conventional thin film electromagnetic converter shown in FIG. 5 and a magnetic head on the read/write device side. 11...Substrate, 12...Magnetic thin film, 13.14...
・Coil, 15.25.35... recess, 15a...
Inner surface, 17...core of magnetic head. Applicant: Toshiba Corporation

Claims (1)

[Claims] A pair of electrically connected coils are each disposed in a spiral shape on a magnetic layer, and magnetic fluxes generated from these coils are directed in opposite directions with respect to a direction perpendicular to the surface of the magnetic layer. In the thin film electromagnetic transducer, a recess is formed in the magnetic layer at a position corresponding to a central portion of each coil, and an end face of the recess of the magnetic layer is exposed. thin film electromagnetic transducer.