JPS60219636A - Magnetic card - Google Patents

Abstract

PURPOSE:To improve the secret security by providing a protecting layer made of a soft magnetic material to the front and rear side of a magnetic film to shield completely the information written on the magnetic film. CONSTITUTION:The protection films 4, 4' made of the soft magnetic material are provided to the front and sides of the magnetic film 2 for magnetic recording and reproduction. The protection film 4' has an effect to shield the magnetic field from the substrate of the magnetic card, the saturation of the protection film 4 is difficult by the reading magnetic field from the substrate side and the reading by use of the magnetic head is difficult. The information is read easily by a reading winding while saturating the magnetic film 2 of the protection films 4, 4' by applying a read magnetic field from the side of the protection film 3.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to magnetic cards that require security, such as cash dispenser cards, ID cards, and the like.

As shown in the cross-sectional view in Figure 1, conventional magnetic cards have a magnetic film 2 for magnetic recording and reproduction made of a magnetic material with high coercive force and a protective film 3 on a non-magnetic substrate 1 made of plastic or the like. It is formed in layers.

However, this magnetic card has the following drawbacks.

In other words, if you ensure the required reading output level, the leakage signal from the magnetic card will increase and you will be able to observe this leakage signal with a magnetic pattern observation device. It cannot be said that sufficient efforts have been made.

The present invention aims to provide a magnetic card that eliminates these drawbacks, and is characterized in that a protective layer made of a soft magnetic material is provided on the front and back sides of a magnetic film for magnetic recording and reproduction.

FIGS. 2 to 4 show cross-sectional views of first to third embodiments of the present invention, respectively.

In FIG. 2, protective films 4 and 4' made of soft magnetic material are provided on both the front and back surfaces of a magnetic film 2 for magnetic recording and reproduction.

In FIG. 3, the magnetic card substrate itself is constituted by a sheet substrate 1' made of a soft magnetic material such as permalloy.

FIG. 4 shows a sheet substrate 1'' made of plastic or paper containing a soft magnetic material as a magnetic card substrate.
A protective film 4' made of a soft magnetic material is further provided between the sheet substrate 1/I and the magnetic film 2. Note that both drawings are views in which the magnetic card is cut in the length direction at the magnetic film 2 region.

The magnetic film 2 is normally formed on a partial region of the substrate 1, so it is sufficient that the protective films 4, 4', etc. are formed on the magnetic film 2.

The features of the present invention will be explained using FIG. 2 as an example.

The thicker the protective film 4' is, the more the magnetic pole of information written on the magnetic film 2 is canceled by the protective film 4', and the leakage signal that appears on the protective film 3 side becomes extremely small. A sufficient effect can be obtained even if it is made thinner.

Note that the thickness tl r j2 of the protective films 4, 4' is tl - tl
The read signal level a for the thickness t of the protective film when
and the leakage signal level b are shown by solid lines in FIG. The broken lines are signal levels a and b when the protective film 4' is not provided. It is clear that increasing the thickness of the protective film 4' will further reduce the leakage signal.

The protective film 4' also has the effect of shielding the magnetic field from the board side of the magnetic card, and even if a reading magnetic field is applied from the board side, the protective film 4'
It is difficult to saturate the magnetic field, and it is difficult to read it by a magnetic head. However, by applying a reading magnetic field from the protective film 3 side, reading can be easily performed using multiple reading windings while saturating the protective film 4 and the magnetic film 2 side of the protective film 4'.

In the embodiment of FIG. 3, the substrate 1' serves both as the substrate l and the protective film 4' in FIG. 2, so it is clear that the manufacturing process can be simplified.

The embodiment shown in FIG. 4 takes into account the case where a sufficient shielding effect cannot be obtained just by making the substrate 1' contain a soft magnetic material, and it is easy to increase the shielding effect compared to the example shown in FIG. 2. can be understood.

As explained above, according to the present invention, the information written on the magnetic film can be almost completely shielded to improve confidentiality, and with the shift to cageless technology, confidentiality has become important. This will have a significant effect on the field of magnetic card use, which is becoming increasingly popular.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional magnetic card, FIGS. 2 to 4 are sectional views of first to third embodiments of the present invention, and FIG.
The figure shows a comparison of characteristics of magnetic cards according to the present invention. In the figure, 1 is a substrate made of a non-magnetic material, 2 is a magnetic film for magnetic recording and reproduction, 3 is a protective film +4 + 4' is a protective film made of a magnetic material, and 1' is a sheet-like substrate made of a soft material. ■“ is a substrate containing soft magnetic material.

Claims (1)

[Scope of Claims] 1. A magnetic film for magnetic recording and reproduction on a magnetic card substrate is shielded by a protective film on its surface, and the back side of the magnetic film is also shielded by a protective film. magnetic card. 2. The magnetic card according to claim 1, wherein the magnetic card substrate is made of a soft magnetic material in the form of a sheet so that the back side of the magnetic film is shielded. 3. The magnetic card according to claim 1, wherein the magnetic card substrate is made of a non-magnetic material mixed with a soft magnetic material so as to shield the back side of the magnetic film. card. 4. The magnetic card according to claim 3, characterized in that a protective film made of a soft magnetic material is provided between the magnetic card substrate mixed with the soft magnetic material and the magnetic film.