AU658254B2

AU658254B2 - Method of recording and reading information

Info

Publication number: AU658254B2
Application number: AU31142/93A
Authority: AU
Inventors: Tatsuya Ogawa
Original assignee: Kyodo Printing Co Ltd
Current assignee: Kyodo Printing Co Ltd
Priority date: 1992-01-13
Filing date: 1993-01-11
Publication date: 1995-04-06
Anticipated expiration: 2013-01-11
Also published as: AU3114293A; GB9300186D0; JPH05294095A; TW222700B; JP3264288B2; GB2263808B; KR970006488B1; GB2263808A; KR930016916A

Description

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

S F Ref: 228338 o o oleo ooo e oer *ee

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Name and Address of Applicant: Actual Inventor(s): Address for Service: Invention Title: Kyodo Printing Co., Ltd.

14-12, Koishikawa 4-chome Bunkyo-ku Tokyo

JAPAN

Tatsuya Ogawa Spruson Ferguson, Patent Attorneys Level 33 St Martins Tower, 31 Market Street Sydney, New South Wales, 2000, Australia Method of Recording and Reading information The following statement is a full description of this invention, including the best method of performing it known to me/us:- 5845/5 -1- METHOD OF RECORDING AND READING INFORMATION BACKGROUND OF THE INVENTION The present invention relates to a method of recording information on a card, such as various prepaid type magnetic cards, by partially removing a vapour deposited metal layer and reading the recorded information therefrom.

As the prepaid magnetic card finds wide application, a magnetic card has been developed that provides a heat-sensitive recording layer allowing information to be recorded by using a thermal recording means (see, for example, JPA Hei 2-62287).

This type of card has a construction in which a contrast applying layer, a heat-sensitive layer, a vapour deposited metal layer and a protective layer are sequentially provided on either surface of a plastic substrate. The thermal recording is achieved by making the thermal head of a thermal apparatus come into contact with the surface of the protective layer. The heat applied by the thermal head is transmitted via the protective layer to the vapour deposited metal layer, thereby boring the metal layer to form a hole portion.

i* In such ,ards, as described above, any arbitrary characters, numerals, or the like, that are formed on the vapour deposited metal layer are seen through the hole S* portion because of the contrast applying layer that is positioned below the metal layer.

Thus, the information corresponding to the hole can be visually read due to the contrast between the hole portion and the non-hole portion of the metal layer.

i: In the foregoing conventional card, the vapour deposited metal layer has been o S

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*e G [N:\libccI00217:HRW f f -2used to record the information such as the debt breakdown or the outstanding balance.

Because the recorded information is visible, the card is not suitable for recording important information, such as the identifying information for determining whether the recorded information is true or false, and therefore such identifying information is recorded on another magnetic layer. However, the information recorded on the magnetic layer is likely to be rewritten, erased, or the like, when any magnetic material comes close to it.

SUMMARY OF THE INVENTION According to the present invention, there is provided a method of reading patterned information, comprising the steps of: providing on a non-electroconductive substrate a patterned information area in which a first information unit comprising a vapour deposited metal layer and a second information unit having the same area as that of said first information unit but having no vapour deposited metal layer are arrayed corresponding to the information to be recorded; scanning said patterned information area using a sensor head fci detecting a :i difference of eddy currents between the first information unit and the second '3 information unit; and •sensing the second information unit dependent on the sensed difference of the eddy currents to read the information.

S e In the present invention, the patterned information formed by partially e o* oe oo*oo* lN;\lbcclOO217:HRW removing the vapour deposited metal layer according to the predetermined pattern is sensed as the series of eddy current signals by the scanning of the sensor head, which is processed to be read as the information.

Therefore, reading of this information is not susceptible to that effect even if there exists a magnetic layer made of metallic fine particles remaining on the trace where the metal layer has been removed by heating, or of the ferrite particles adjacent to the vapour deposited metal layer.

As described above, according to the present invention, the patterned information formed by partially removing the vapour deposited metal layer according to the predetermined pattern is sensed as a series of eddy current signals by scanning using the sensor head. The sensed signal is processed to be read as the information. In consequence, the reading of the information can be reliably achieved in a non-contact manner. Unlike the conventional method of reading the information, such as a bar code using any optical means, it is possible to assure a high reliability of reading the information even if some stain adheres to the priited surface of the magnetic card, or the latter is hidden by an opacifying layer. An extremely high safety factor is thereby achieved by keeping the information confidential and preventing counterfeiting.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. i1 is a perspective view showing how the information recorded on a

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[N:\libcc100217:HRW i t -4magnetic card is read according to the method of the present invention; Fig. 2 is a partial cross-sectional view of the magnetic card shown in Fig. 1; Fig. 3 is a graph illustrating a relationship between the removed portion and the output voltage at the patterned information area formed on the metal layer of the magnetic card shown in Figs. 1 and 2; Fig. 4 illustrates the relationship between the removed portion, output voltage and digital output at another patterned information area provided on the magnetic card embodying to the present invention; Fig. 5 is a block diagram of a signal processing circuit for obtaining the digital output of Fig. 4(c) from the signal of Fig. 4(b); Fig. 6 is a block diagram of an apparatus for recording and reading the information embodying the present invention; Fig. 7 shows part of a card in perspective view illustrating a relationship between the removed portion and the magnetic recording and reproducing track at the patterned information area of the magnetic card; and Fig. 8 is a flowchart of the operation of determining, using the apparatus of Fig. 6, whether the magnetic card shown in Fig. 7 is valid.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The principle of reading information according to the present invention will be described with reference to the accompanying drawings for a case in which the j* *o o* o *o* g• *OOO41°O IN:\libcc]00217:HRW information provided on a general magnetic card is read out.

Referring now to Figs. 1 and 2, a magnetic card designated C comprises either one surface of a substrate 1 which comprises a magnetic layer 2, a vapour deposited metal layer 3, an opacifying layer 4 and a wear-resistant protective layer 5 formed in the order mentioned, and a printed layer 6 for forming any visual sign or pattern that may be provided between the opacifying layer 4 and the protective layer 5, as necessary. In the vapour deposited metal layer 3, a non-removed, deposited portion 3A constituting each information unit and a removed portion 3B are formed according to predetermined patterned information.

A sensor head S used in this embodiment is provided with an oscillating coil, which is connected to an oscillating circuit (not shown), to generate a high frequency magnetic field.

When the sensor head S is shifted along the patterned information area of the magnetic card C, at the non-removed portion 3A where the metal layer 3 is present, an eddy current is generated on the surface by electromagnetic induction. This eddy current acts to reduce the oscillating energy of the oscillating coil so that the oscillating amplitude is reduced at the portion where the metal layer is present. Further, when the removed portion 3B passes under the sensor head S in the process in which the sensor head S scans the patterned information area of the magnetic card, the eddy current is plb*e 20 reduced or stopped and the oscil1-ting amplitude becomes greater.

*oo 041 *ie Ol** e IN:\libccl00217HRW That is, when the patterned information area of the card is scanned by the sensor head S, the oscillating amplitude becomes smaller at the non-removed portion 3A and becomes greater at the removed portion 3B. By sensing the change of this amplitude using any proper means (for example, rectification as shown in Fig. a series of sensed signals of L level can be obtained at the non-removed portion 3A of the vapour deposited metal layer 3, and that of H level can be obtained at the removed portion 3B, where the information is read out.

In the embodiments of Figs. 1 through 3, although the length (information unit) taken in the scanning direction of the sensor head S substantially equals that taken in the scanning direction of the sensor head S, if this length is set to about one half of that taken in the scanning direction of the sensor head S, the information can then be recorded at a density twice as large at a patterned information area of the same length.

Referring more specifically to Fig. 4, the patterned information area is arranged with a series of information units shown in Fig. Each information unit takes about one half of the length LI of the sensor head S taken in the scanning direction. Furthermore, each information unit, as shown in Fig. comprises nonremoved portions 21A and removed portions 21B according to the desired information.

Fig. 4(a) illustrates a specific example of these non-removed and removed portions 21A 0 9 0* 0 000000 IN:\libccl00217:HRW -7and 21B. The portion applied with the oblique lines corresponds to the non-removed portions 21A.

If this patterned information area is scanned by the sensor head S of length L1, a sensed signal shown in Fig. 4(b) can then be obtained as its output. Two threshold levels TL1 and TL2 are set for this sensed signal, and the level of the output signal is compared with these threshold levels TL1 and TL2 to obtain digital signal outputs comprising a series of logic values or as shown in Fig. 4(c).

The following Table 1 shows a method of processing the sensed signal when the information unit equals about one half of the length of the sensor head S taken in the scanning direction.

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[N:\llbcc00217:HRW TABLE 1 State of the Sensed Signal Output Value Level L>TL2 1 Level L<TL1 0 5 TL2>level L>TL1 When the differential circuit determines that the level change of the signal is positive and that Sit exceeds the threshold level: 1 t f to When the threshold circuit determines that the level change of the signal is negative and that it exceeds the threshold level: 0 beefm When the level change of the signal .*eo 1S' does not exceed the threshold level: The preceding state is inverted.

Fig. 5 illustrates a specific example of the signal processing circuit for obtaining the digital signal from the signal as shown in Fig. In Fig. 5, a numeral S denotes a sensor head, 44\a synchronizing signal output corresponding to the shift when this sensor head S is carried along the patterned information area of the magnetic card. The output of the sensor head S, after amplification, is simultaneously inlput to an A/D converting circuit 13 and a differential circuit 14.

A level setting circuit 15 sets two threshold levels TL1 and TL2 of the inut signal shown in Fig. A level determining circuit 16 compares the level L of the signal from the A/D converting circuit 13 with the threshold levels TL1 and TL2.

When the level L exceeds the threshold level TL2 or is below the threshold level TL1, it sends the signal representing each state to an output control circuit 17. On the other hand, when the level L lies between the threshold levels TL1 and TL2, a signal representing that state is supplied to two AND circuits 18 and 19 and a level holding circuit On the other hand, the differential circuit 14 determines whether the level change of the signal from the A/D converting circuit 13 is positive or negative. When the level change is positive, the differential circuit 14 sends the output to the AND circuit 18, whereas when the level change is negative, the differential circuit 14 sends the output to the AND circuit 19. That is, when the level L lies between the threshold levels TL1 ard TL2 and its value is rising, the AND circuit 18 supplies the output of a level determining circuit 16 to the level holding circuit 21. When the level L lies i between the threshold levels TL1 and TL2 and its value is falling, the AND circuit 19 supplies the output of the level determining circuit 16 to the level holding circuit 22.

20 The level holding circuits 20-22 hold the given level until the next pulse is supplied.

IN:\libcc)00217HRW Upon receipt of the outputs from the level determining circuit 16 and the level holding circuits 20-22, the output control circuit 17 emits a digital signal of or "0" depending on the absolute value of the output signal level of the sensor head S and the direction in which this level is changed. The corresponding relationship between the s patterned information of the magnetic card and the output signal of the output control circuit 17 is shown in Fig. 4(b) and Fig. 4(c).

Fig. 6 is a block diagram of a specific embodiment of an apparatus for recording and reading the information according to the present invention. Fig. 7 is a partial perspective view illustrating a relationship between the removed portion 3B of the patterned information area and the magnetic recording/reproducing track MT of the magnetic card. Fig. 8 is a flowchart of the operation of determining, using the apparatus of Fig. 6, whether the magnetic card of Fig. 7 is valid.

Referring to these figures, the operation of determining, according to the present method of recording/reading the information, whether the magnetic card of Fig.

7 is valid is hereinafter described.

In Fig. 7, it is assumed that the magnetic recording/reproducing track MT and the removed portion 3B of the patterned information area overlap, in which the type of .:°card, the outstanding balance and the information for determining whether the magnetic card is valid, which is included within the non-removed portion 3A and the removed

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IM A% c00217:HRW 0 0 *0*S portion 3B of the patterned information area, is formed. The non-removed portion 3A and the removed portion 3B of the patterned information can be provided at any arbitrary position of the card C, but, in this embodiment, they are provided along the long side of the card C.

First, the magnetic card C is inserted into an information reading apparatus (not shown), which comprises a CPU, memory M, main control unit C, reproducing magnetic head MH1, recording magnetic head MH2, thermal head TH and eddy current sensor S. When the magnetic card C is inserted, this apparatus starts to operate (F1), reads out the information formed by the non-removed portion 3A and the removed portion 3B of the patterned information area using the eddy current sensor S and then reads out the information recorded on the magnetic recording/reproducing track MT (F3).

Next, the CPU compares the read information of the non-removed portion 3 A and the removed portion 3B with the information recorded on the magnetic recording/reproducing tracLc MT (F4) to determine whether the magnetic card C is true or false. If, as a result, the card C is determined to be true (Yes), then the predetermined service can become available otherwise, if it is determined to be false then it is determined to be counterfeit, the service becomes unavailable (F10), and the card C is rejected (Fll).

20 On the other hand, for the card C which was determined to be true, after the **o IN:\llbccl00217:HrRW service becomes available the current service utilising state (withdrawn sum of money) is compared with the outstanding balance recorded on the magnetic recording/reproducing track MT In this case, if it is determined to be unavailable, the card C is determined to have been counterfeited, the service becomes unavailable (F10) and the card C is returned (F11). However, if it is determined to be available, then the available sum of money, the patterned information is updated by removing the vapour deposited metal layer (Fig. 2) using the thermal head TH (F7).

The magnetic information of the magnetic recording/reproducing track MT is then updated using the recording magnetic head MH2 If this process is completed, the card C is returned (F10) to end the process.

As described above, according to the present invention, even if the nonremoved portion 3A and the removed portion 3B at the patterned information area and the magnetic recording/reproducing track MT overlap one over the other), the recording area can be widely taken without one information recording/reproducing operation affecting the recording/reproducing operation. In addition, since the nonremoved portion 3A and the removed portion 3B of the patterned information area cannot be visually recognised, it is difficult to read correctly its patterned information by other means, thereby retaining a high security level.

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EXAMPLE

A magnetic card arranged as in Fig. 2 is formed on either side of substrate 1 by laminating a magnetic layer 2, a vapour deposited metal layer 3, an opacifying layer 4 and a wear-resistant protective layer 5 in the order mentioned.

In this embodiment, as the substrate 1, a plastic sheet of thickness 188 microns which is made of polyethylene telephthalate, is used but other materials can be used such as a synthetic resin or synthetic paper sheet such as epoxy resin, polyvinyl chloride and polycarbonate.

The vapour deposited metal layer 3 can preferably be formed by a conventional vacuum vapour deposition technique to form a thin layer having a thickness of about 200 angstroms on the magnetic layer 2.

The opacifying layer 4 has a proper opaqueness, that is, a hiding capability to thereby visually hide the vapour deposited metal layer 3. The opacifying layer 4 can be a film of thickness of 2-4 microns which is formed by applying and drying a paint made of polyester series resin of 10 parts by weight, a solvent of 30 parts by weight and aluminum flakes of 5 parts by weight on the vapour deposited metal layer 3.

The protective layer 5 is intended for protecting the surface of the magnetic card, and is comprised of a polyester series resin of thickness of about 1 micron. For i the protective layer, other materials that have excellent wear-resistant and heat-resistant characteristics, such as cellulose resins, urethane resins, vinyl resins, epoxy resins, *o IN:\libcc00217:HRW acrylic resins or the like can be used. Any combination of the phthalic acid esters, fatty acid esters, phosphoric acid esters or the like can be added as plasticiser to those resins.

To apply slidability to the protective layer 5, low molecular weight polyethylene, oleyl amide, stearile amide, silicone or the like can be added. The preferred range of the thickness of this protective layer 5 may be 0.1 to 10 microns, and more preferably about 1 to 5 microns.

By making the thermal recording head contact the magnetic card C on the surface of this protective layer 5 for printing according to the ordinary thermal recording system, three removed portions 3B1, 3B2 and 3B3 were formed, which each have a width equal to about 5 mm and a length that varies between about 5 to 10 mm.

The portion other than each removed portion corresponds to the non-removed portion 3A.

The sensor head S was shifted at a constant speed of 20 mm/sec to scan the patterned information area in the direction of its length. Incidentally, the interval between the surface of the magnetic card C and the top end of the sensor head S was held constant at 1 mm.

The relationship between the removed portions 3B1, 3B2 and 3B3 formed on i. the vapour deposited metal layer 3 and the voltage signal sensed by the sensor head S is *0 illustrated in Fig. 3. As shown in this figure, the output voltage obtained from the 20 removed portions 3B1, 3B2 and 3B3 is sufficiently high as compared with the output voltage 4 :4 I o *0 a [N:\llbccl00217:HRW obtained at the non-removed portion 3A. According to the experimental result, a voltage difference of about IV was obtained.

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Claims

1. A method of recording and reading information, said method comprising the steps of: providing on a non-electroconductive substrate a patterned information area in which a first information unit comprising a vapour deposited metal layer and a second information unit having the same area as that of said first information unit but having no vapour deposited metal layer are arrayed corresponding to said information to be recorded; scanning said patterned information area using a sensor head for detecting a difference of eddy currents between said first information unit and said second information unit; and sensing said second information unit from said difference of said eddy currents to read said information.

2. The method according to claim 1 wherein said information unit at said patterned information area has substantially the same area as that of a detection surface of said sensor head.

3. The method according to claim 1 wherein said first and second information units at said patterned information area each have a length equal to aapproximately one half of the length of a detection surface of said sensor head in 20 relation to the scanning direction of said sensor head. S *e s a a S S [N\libcc00217:HRW -17-

4. The method according to claim 3 wherein, when an output level of an output signal obtained each time said sensor head passes through an information unit is stable at a constant value of below a first threshold level and said output level is reduced relative to the change of the preceding level, a first digital value is obtained, and when the level is increased and is stable at a constant value exceeding a second threshold level which is higher than said first threshold level, a second digital value is obtained. A method of recording and reading information substantially as described in the specification with reference to Figs. 1-8 of the accompanying drawings. DATED this Sixteenth Day of January 1995 Kyodo Printing Co., Ltd Patent Attorneys for the Applicant SPRUSON FERGUSON *eae S [N:\libccl00217:HRW Method of Recording and Reading Information ABSTRACT A method of reading patterned information formed by partially removing a vapor deposited metal layer (3 in Fig. 1) of a card (C) according to a predetermined pattern wherein it is sensed as a series of eddy current signals by scanning by a sensor head which senses the difference of the eddy current between the portion (3A) having the vapor deposited metal layer and the removed portion (3B1, 3B2, Thus, the information can be reliably carried out in a non-contact manner and, even if it is hidden by an opacifying layer it can be read out thus assuring an extremely safety factor in keeping it confidential and preventing it from being counterfeited. I Figure 1 SoS S *5 5t50o *o ch/9202W