JPS63313082A - Measuring instrument for magnetism characteristic of magnetic thin film - Google Patents

Abstract

PURPOSE:To measure the magnetism characteristic distribution of a magnetic thin film automatically in a short time without deforming nor breaking a magnetic tape, etc., as a sample by applying a low-frequency signal to a magnetic measurement part where plural differential magnetic heads are constituted linearly. CONSTITUTION:Magnetic measurement parts 201-208 have magnetic heads 1 constituted by integrating magnetic cores and cancel cores, each magnetic head 1 is provided in a magnetic head part of a multihead type magnetic sensor, and this magnetic sensor constitutes a differential magnetic head. The magnetic core of the magnetic head 1 is wound with primary coils 2 and 3 and secondary coils 4 and 5 separately from each other. A triangular wave signal SD 2 of about 1-10Hz low frequency is inputted to the primary coils 2 and 3 from a measurement data conversion part 21 through an amplifier 19, and differential output voltages from the differential magnetic heads are sampled and converted into digital values by the conversion part 21, and converted digital values are stored successively and a measurement data analytic part calculates magnetism characteristic values of a magnetic thin film at plural positions.

Description

Detailed Description of the Invention (Technical Field of the Invention) The present invention relates to a method for accurately and quickly measuring the magnetization characteristics of magnetic thin films of magnetic recording media such as magnetic tapes, 611 stripes of magnetic cards, and magnetic disks. This invention relates to a magnetization characteristic measuring device.

(Technical background and problems to be solved) With the progress of the information society, magnetic recording media such as magnetic cards or data recording media such as magnetic tapes and magnetic disks have already become a large market, and will continue to grow in the future. It is easy to predict that it will develop further. There are a lot of these media.

In order to achieve stable and low-cost production, further progress in research and development 1 is required to improve the quality level, and one way to support these efforts is to measure the magnetization characteristics of the media. The device is in use. For example, current devices for recording the magnetization characteristics of magnetic thin films such as magnetic tapes include the Model 3257 DC magnetization characteristics automatic recording device manufactured by Yokoretsu Denki Co., Ltd., B) 1s-40, BH) 1 manufactured by Riken Denshi Co., Ltd. -50
．． BIIU-60 type direct current magnetization B-11 characteristic automatic recording device and the like have been commercialized.

Here, as an example of a detection method using the above device, a general method for detecting magnetization characteristics in a ring-shaped sample will first be described. When a magnetic field H is applied to the magnetic material to be measured,
The amount of magnetic flux Φ generated in the magnetic material changes depending on this magnitude. A graph of this situation, with the magnetic field H on the horizontal axis and the magnetic flux Φ on the vertical axis, is called a magnetization curve (hysteresis loop), and this magnetization curve is generally obtained with the configuration shown in Figure 22. . That is, the magnetizing coil 1-01 is wound on the primary side of the annular magnetic body 100 (number of turns Nl), and the detection coil 102 is wound on the secondary side (
Number of turns N2). Then, a low frequency sine wave is applied from the low frequency oscillator 103 to the magnetizing coil 101, and a resistor R
1 is inserted in series.

Here, since the magnetic field H inside the magnetic body 100 can be considered to be proportional to the current ■1 flowing through the magnetizing coil 101,
Letting the magnetic path length at 0°C be as follows. On the other hand, the generated magnetic flux Φ
is obtained by integrating the output voltage V of the detection coil 102. In other words, the output voltage VC is (2). By measuring such voltages V, , Ve, a magnetization curve (Φ-H curve) can be obtained.

Furthermore, if the voltage v2 is plotted on the vertical axis, an output proportional to the magnetic permeability can be obtained.

A magnetic substance measuring device based on such a principle is described in "Yokogawa Technical Report Vol. 1.17 No. 2" published in 1973, from pages 49 onwards.
It is stated on page 72. However, although this measuring device has versatility by measuring high magnetic permeability materials, plates such as permanent magnets, block materials, magnetic powder, 6B thin films, etc., it has drawbacks such as functionality, operability, and price. be. In addition, this measuring device can measure the magnetization characteristics of, for example, magnetic stripes created by thermal transfer or coating on paper cards, cards and passbooks with magnetic tape pasted, magnetic cards with coatings on the surface, etc. Cut a magnetic thin film from a card, etc., and prepare it for a certain size according to the structure of the device.
As shown in the figure, it was necessary to use a sample 110 with a thickness of approximately <10 sheets, which was very troublesome. Furthermore, it has been impossible to measure the magnetization characteristics of the magnetic stripe of a magnetic card or the like while it is layered on the magnetic card.

For the reasons mentioned above, it has conventionally been very difficult to measure the absolute value of the magnetization characteristics of magnetic strip media, disk media, and the like.

Therefore, as a compatibility standard, relative value evaluation with standard media (for example, JISB9560-1979.JIS6291-1
986) is defined. However, in this evaluation method, the influence of the magnetic field from the magnetic head is also included in the measured values, so there is a drawback that the characteristic values of the medium itself cannot be clarified. Furthermore, X-Y
The user must visually read and calculate magnetization characteristic values such as saturation magnetic flux, residual magnetism, and coercive force from a hysteresis curve once drawn on paper using a recorder, etc., which is very time-consuming. It was on. Moreover, there is still no equipment that can measure the distribution of magnetization properties of magnetic stripe media, disk media, etc. or analyze the process capability of magnetization property values. In order to measure multiple points on a magnetic thin film with one magnetic head (single head), a mechanism for moving the magnetic head or medium is required.

Therefore, a measurement method using a plurality of magnetic heads (multi-head) can be considered. For example, a method can be considered in which the data at the first location on the magnetic thin film is read in the first cycle, and the data at the second location in the magnetic thin film is read in the next cycle, without switching the output voltage channel of the multi-head. .

However, with this method, unless a high frequency is used for the excitation signal, the measurement takes a lot of time.

Moreover, since a high frequency is used, there is a drawback that eddy currents are generated in the medium itself during measurement and are affected. or,
Currently commercialized devices are configured by combining, for example, an excitation section, a signal processing integrator, a recorder, etc. as individual devices, and have the disadvantage that the devices themselves are extremely large.

(Object of the Invention) This invention was made in view of the above-mentioned problems, and an object of the invention is to determine the magnetic property distribution of a magnetic thin film of a magnetic recording medium such as a magnetic tape, magnetic stripe, or magnetic disk. It is an object of the present invention to provide a magnetization characteristic measuring device that can measure automatically and in a short time without physically destroying or deforming a tape or the like by cutting it.

(Means for Solving the Problems) The present invention relates to an apparatus for measuring magnetization characteristics of a magnetic thin film. A differential magnetic head in which at least one cancellation core is integrated in a line, excitation signal generation means for exciting the differential magnetic head with a repetitive signal, and a magnetic thin film to be measured is located on or near the magnetic thin film. measurement data conversion means for sequentially sampling a plurality of differential output voltages from said differential magnetic head and converting them into digital values; and a measurement data conversion means for sequentially storing the digital values converted by said measurement data conversion means; This is achieved by providing a measurement data analysis means for calculating the magnetization characteristic value of the magnetic thin film.

(Function of the Invention) In the present invention, a magnetism measurement unit including a plurality of differential magnetic heads configured in a line is positioned on or near a magnetic thin film, and a low frequency signal is applied to the plurality of differential magnetic heads. The data converter sequentially switches each differential output voltage to the cancellation core of the type magnetic head and converts it into digital data.Based on this data, the measured data analyzer calculates the magnetization characteristic value of the magnetic thin film through software integration. I try to ask for it. As a result, it is possible to obtain the magnetization characteristic values of multiple locations on the magnetic thin film at the same time, and furthermore, by relatively moving the magnetic thin film or the magnetism measurement unit, the magnetization characteristic values of the entire surface of the magnetic thin film can also be obtained at high speed. be able to.

(Embodiment of the Invention) Figures 1 and 2 show the circuit system of the magnetization characteristic measuring device (hereinafter simply referred to as the measuring device) of the present invention in block configuration. A plurality of (eight in this example) magnetism measurement units 201 to 208 that measure the magnetization characteristics of a magnetic thin film of a recording medium, and these magnetism measurement units 201
A measurement data conversion unit 21 that converts the voltage signals VDI to VOa measured in ~208 into digital signals and generates a triangular wave signal SD2 that drives the magnetism measurement units 201 to 208.
Then, the digital signal converted by the measurement data converter 21 is processed by a computer to display the magnetization characteristic value,
The measurement data analysis section 60 has functions such as determination of the quality of magnetization characteristics and self-diagnosis.

Next, details of each of the above parts will be explained.

The magnetism measurement units 201 to 208 have the same configuration, and each has a magnetic head 1 in which a vertically and horizontally symmetrical H-shaped magnetic core and a cancellation core are integrated.
Each of magnetic heads 1 to 208 is a magnetic head section 211 of a linear multi-head magnetic sensor 200 shown in FIG.
~218, respectively. This multi-head magnetic sensor 200 constitutes a differential magnetic head.

With such a magnetic sensor 200, the magnetization characteristic of the magnetic stripe portion 301 of the magnetic card 300 shown in FIG.
It is possible to detect the time between places.

Since the structures of the magnetism measurement sections 201 to 208 are similar, the magnetism measurement section 201 will be explained here. On the magnetic core of the magnetic head 1, primary coils 2 and 3 connected in series with N turns are wound, and secondary coils 4 and 5 with N2 turns are wound separately. . 1 to 1 from the measurement data converter 21 to the primary coils 2 and 3.
A triangular wave signal SD2 having a low frequency of about 0 Hz is input manually via an amplifier 19. The lower part of the magnetic core 1 has a detection side gap part IA, and the upper part has a non-detection side gap part IB.
are provided for each. Output voltage v of secondary coil 4
s is obtained via an amplifier 10, the output voltage VSC of the secondary coil 5 is obtained via an amplifier 11, and the output voltages vS and VSC are input to a differential amplifier 12. Here, amplifier 10. Amplifier 11. The gain of the differential amplifier 12 is set to "1°" for convenience.

Here, the measurement of the magnetic head 1 will be explained. First, the cross-sectional area of the magnetic core 1 of the coil part is S,
The magnetic core cross-sectional area of the gap portion IA is set as S6. Let the core magnetic path length be and the gap length be f! , □, Let the magnetic permeability of the magnetic core be μ, and the magnetic permeability of air be μ0. Then, the magnetic flux Φ in a state where no medium is brought into contact with the gap part IA is as follows, assuming that the magnetic resistance of the magnetic core 1 is n (-f17μs) and the magnetic resistance of the gap part IA is R□ (-J2i/μOSt>). The relationship between the magnetic field 11g of the gap portion IA and the brush field 11g and the TL flow (2) is as follows.

Next, due to the relationship of magnetic resistance n<<n, as shown in FIG. The state is almost parallel to the direction of the gap length 15. Now, if the magnetic flux when the magnetic thin film 310 is brought into contact with the gear part 1 is Φ1, then the electromotive force v8 of the secondary coil 4 is... (7)... ...(8), and the electromotive force VSC of the secondary coil 5 on the non-detection side has a magnetic flux of Φ. Then, it becomes . Therefore, the differential output voltage vDA of the differential amplifier 12 is expressed by equations (7) to (9).
When there is no rlA310, it is, and when there is a 6n thin film 31O, it is. Here, the magnetic flux Φ is converted into a low-frequency triangular wave S by the measurement data converter 21.
Since D2 is applied to the primary coils 2 and 3, it monotonically increases or decreases. The output voltage vDA+VD+ of the differential amplifier 12 is digitally converted by the measurement data converter 21, taken into the measurement data analyzer 60, and stored in the memory unit 61.
The magnetic @ film 310 was set by storing the data in the RAM 62.63, synchronizing with the applied magnetic field H, reading the data from the RAM 62.63, and taking the difference between (lO) and (11). Output voltage V based on the increment of magnetic flux Φ by. ° can be calculated.

Note that the output voltage V of the differential amplifier 12 when the magnetic thin film 310 is not present. Since A is almost close to the stem, it may be sufficient to roughly detect the output voltage VDA by increasing the manufacturing precision of the magnetic core 1.
is ; (if the characteristics of the canceling side and the detecting side are completely matched, it becomes ■, ·VSC), the differential output voltage V. There is no need to import A into the measurement data analysis section 60; It can be A'.

If the cross-sectional area of the magnetic thin film 310 is Sl (-thickness dX width W), the magnetic flux density 131 in this part is Φ, -Φ
-Φ'-81・Sl ・・・・・・・・・(
13), and from equation (12), we get (14).

The magnetic permeability μm of the magnetic thin film 310 is (to be exact, the 611 conversion rate χ
So, μ, −χ ・μm°−1. μ and ° are true magnetic permeability). Software integration is performed by adding data at each magnetic field strength in equation (12).

In other words, it follows that (16). Here, Δ is the sampling period, and the addition corresponds to one period of the applied magnetic field H.

Now, to explain the above software integration, the characteristic (2) in FIG. 6 is the voltage V according to the above equation (12) with respect to the magnetic field H.

It shows the change v(II) of A', and an arbitrary point in this temporality (2) is defined as vl.

Next, from this initial value v1, the data sampling period ΔI
Use I to obtain the following integral value ψ.

(18) Therefore, the value ψI+ corresponding to the magnetic flux Φ11. is the horizontal axis H (
(magnetic field). This characteristic is indicated by II in FIG. In other words, by integrating characteristic (2) in FIG. 6 from vl, a curve of characteristic 11 is obtained.

The magnetic flux Φ' can be determined by making the following corrections.

Φ′ = Φ(II) = Φum. .

(19) Here, ψ1 and ψ1□ are assumed to be symmetrical values with respect to the center of gravity of the magnetization curve. Note that ψ1 does not necessarily have to be an initial integral value, but may be a value symmetrical to the center of gravity. Here, n is the initial value i
represents an integer counted every sampling period ΔH from ΔH.

The magnetic field H and magnetic flux Φ obtained as above.

When a magnetization curve is drawn, it becomes a curve in which the characteristic I+ is shifted in the vertical direction as shown in FIG.

Next, the measurement data converter 21 will be explained.

The measurement data conversion section 21 is provided with a parallel input/output interface 17 for communicating data with the measurement data analysis section 60 , and the control signal 501 from the parallel input/output interface 17 is transmitted to the triangular wave generation circuit 1 .
8, a triangular wave signal SD2 is generated and sent to the amplifier 1.
9 to the magnetism measurement units 201 to 208. This triangular wave generation circuit 18 includes a clock pulse oscillator 80,
A counter 81 starts counting clock pulses in response to a control signal SDI, a ROM 82 in which digital data for triangular wave generation is individually stored at an address corresponding to the count signal of this counter 81, and digital data is read out from a predetermined address of this ROM 82. and a D/converter 83 that performs D/A conversion on the digital data to create a triangular wave signal SD2.

Moreover, the voltage Vo output from the magnetism measurement units 201 to 208
+ -Voa (when there is a magnetic thin film), VDA
A multiplexer 24 is provided to sequentially switch and take in VDH (when there is no magnetic thin film), and the multiplexer 24 is driven by a switching signal from the counter 81. The voltages VDI to vD8+VDA ''VDH sequentially output from the multiplexer 24 are amplified via the amplifier 13 and input to the sample and hold circuit 14.The sample and hold circuit 14 receives the timing signal from the counter 81 of the triangular wave generation circuit 18. SH causes the above voltages VDI to VOa and V.A to VDH.
Sample the sampling data SD3 ^/
Power is applied to the D converter 15. The A/D converter 15 converts the sampling data 503 into a digital signal DSI in response to the conversion start signal C0NV from the counter 81 of the triangular wave generation circuit 18, and transmits it to the measurement data analysis section 60 via the parallel input/output interface 17.

Next, the measurement data analysis section 60 will be explained.

The measurement data analysis section 60 is provided with a CPIJ 73 that controls each section, reads data from the RAM 62 and 63 of the memory section 61, and performs calculations (software integration), and a ROM 69 that stores control programs and the like. , an RA that stores differential output voltage data of the magnetic head l when the magnetic thin film 310 is on the magnetic head 1.
A memory section 61 is provided, which has an opening M62 and an opening M63 for storing differential output voltage data of the magnetic head 1 in the absence of the magnetic thin film 310, and for storing various other human input data. Furthermore, a clock 64 for displaying date 1 time on a display 68 is provided, and a GP-IB interface 22 and a parallel input/output interface 70 are provided as interfaces. An output connector 23 for 18 is connected to the parallel input/output ink face 70, and a buzzer 72 that notifies the quality of the magnetization characteristics with sound, and a printer output connector 71 for outputting the magnetization characteristics values to a printer are connected to the parallel input/output ink face 70. There is. Further, as controllers, a controller 67 for driving a display 68 and a key controller 2 for controlling input data from the keyboard 29 are provided.
8, and video RAMs 65 and 66 that store images for two screens are connected to the controller 67.

In such a configuration, the operation of the measuring device will be explained with reference to the flowchart shown in FIG.

First, turn on the power switch of the measuring device and press keyboard 2.
The pass range of the magnetization characteristic value of the magnetic thin film 310 to be measured and the range setting value of the magnetization force (for example, 100
0[Oel ~ 10000[IO stage up to Oel]
When inputting (step St), data in the acceptable range is stored in the memory section 61 of the measurement data analysis section 60. The data in this passing range is the saturation magnetic flux Φm (saturation magnetic flux density B
m), residual magnetic flux Φr (residual magnetic flux density Br), coercive force 11
C, squareness ratio D (-Φ"/Φm-0r/BI11), etc. Next, a mode is selected using the keyboard 29 (step S2), but when the measurement mode is selected. The magnetic card 300 to be measured is inserted and placed on the table (not shown) of the measuring device, and the magnetic thin film 310 of the magnetic stripe section 301 is positioned, for example, in alignment with the marker (step 53). Magnetic thin [
When the key operation is performed after reconfirming that the measurement part 310 is not shifted, the magnetic sensor 200 is positioned on the magnetic thin film 310 of the magnetic card 300 set as shown in FIG.
After that, the measurement data analysis unit 60 converts the measurement data into the measurement data conversion unit 2.
A control signal is transmitted to the magnetization device 1, and measurement of magnetization characteristics is started (step S4). The counter 81 is controlled by the control signal SDl.
starts counting up, and the triangular wave signal 502 generated by D/A converting the digital data stored in advance at the address in the ROM 82 corresponding to this count signal passes through the amplifier 19 to the magnetism measurement units 201 to 201. 2
08 is applied to the primary coils 2 and 3 of each magnetic head 1,
A magnetic field H is generated between the gaps IA and IB of each magnetic head 1. The secondary coil 4.5 generates a voltage proportional to the time change of the magnetic flux flowing in the magnetic core 1, and the amplifier 10
．． 11 and the differential amplifier 12, the voltage signal vow~v
oa is obtained, and these VDI to voa are sequentially selected by the multiplexer 24 in the measurement data converter 21 and input to the sample and hold circuit 14. Then, the sampling data SD3 is converted into a digital signal DSI by the A/D converter 15, and then sent to the parallel input/output interface 1.
The measurement data analysis section 60 manually inputs the measured data via 7. Here, FIG. 25 (8) shows the waveform of the count pulse emitted from the clock pulse oscillator 80, FIG. 25 (B) shows the triangular wave SD2 emitted from the D converter 83 in response to the count pulse, and FIG. The diagram (D) shows how the multiplexer channels are selected.
The sample hold signal SH input manually is shown in the same figure (E).
is the conversion start signal C0 input to the /D converter 15
A timing chart of NV is shown. In other words, the counter 81 is the clock pulse oscillator 80 as shown in FIG. 25(A).
n0M8 based on clock pulses unearthed as
2 and from the D/A converter 83 as shown in FIG.
A triangular wave 502 shown in FIG. Then, for example, every time eight clock pulses are counted, a switching signal is input to the multiplexer 24, and the channel of the multiplexer 24 is switched as shown in FIG. 25(C).
l→CH2), and after switching, the second
As shown in FIG. 5(D), a sample-and-hold signal 511 that has been extended by one clock pulse, for example, is input to the sample-and-hold circuit 14. And sample hold circuit 1
4, any one of the voltage signals VDI to VD8 input from the multiplexer 24 via the amplifier 13 is sampled and held.

The A/D start signal C0NV delayed by one clock pulse is input to the A/D converter 15 as shown in FIG. D-converted. In this way, when all the voltage signals VDI to VOa for one cycle of the triangular wave are stored in M62 at predetermined time intervals,
The magnetic sensor 200 is removed from the magnetic thin film 310, and in the same way, the voltage signal VD for one cycle of the triangular wave is detected at predetermined time intervals.
A “”’VDH is stored in M63 to R, and then lΔ
The signals corresponding to each of M62.63 are subtracted. The hysteresis curve, magnetization characteristic values Φr (Br), Φm (Bm), ti calculated by the CPL 173 as described above
c, D, etc. are each stored in the memory unit 61 as measured values (step S5). The CPU 73 compares the above measurement value with a preset pass range and displays the result on the display 6.
8, the pass/fail status is displayed as, for example, rOK, rNG, and the hysteresis curve, measured value, etc. are displayed. Further, based on the above measurement results, the distribution characteristics are displayed on the display 68 as shown in FIG. 9, and are also stored in the video RAM 65, 66 via the controller 67. Also, the buzzer 72 is connected via the parallel input/output interface 70.
If the answer is "OK", the buzzer 72 generates a continuous sound such as beeps (steps S6 and 5).
7), In the case of the above rNG, for example, “pippi...
- generates an intermittent sound (steps S6 and S8). As described above, the magnetic head sections 211 to 2 of the magnetic sensor 200
18, the magnetization characteristic values at eight locations of the magnetic stripe section 301 can be obtained simultaneously, and these magnetization characteristic values are as follows.
Both are stored in the memory section 61 (step S9).

Note that the memory area of the memory unit 61 is 100 in RAM.
A portion of data is secured, and the data is sequentially logged along with measurement time data from the clock 64 in chronological order.

Furthermore, according to the measuring device of the present invention, the magnetic strip section 3
01 can be measured. That is, from the detection state as shown in FIG.
The entire magnetic stripe section 301 can be measured by moving the magnetic sensor 200 or the magnetic card 300 by a predetermined amount by a pitch of 218 (step 5ll) and repeating the measurement of the 8-tube bamboo grass as described above. can. In addition,
If sample measurements at eight locations are sufficient, it is not necessary to carry out overall measurement by moving one pitch.

On the other hand, if mode conversion is not designated by the key input, the system waits for the measurement of the next magnetic card, and if the data processing mode r is selected by the key input after measuring multiple magnetic cards (step 512.S2), [: The PU 73 calculates the logging data in the memory unit 61 and
), (B) A ×-8 control chart of the selected specific magnetization characteristic value (for example, Φr at the location measured by the magnetic head 211) is displayed on the display 68 (step 514). Here, to explain the procedure for creating an X-R control chart, first of all, the prerequisite is N:
Set the total number of data, n: group size, and: number of groups.

Then, N is the automatic counting of data in the memory, and n is the user's manual effort (selected from n=3.4.5). Also, k is the quotient obtained by =N/n, and the remainder data is not used. For example, N=98. When n=3, set it to =32,
Data after the 97th is not used. Average value for each group
is, the total average value X of the average value X for each group is (-CL), and the upper and lower control limit lines UCL and LCL are UCL
=x+^2R---(22) LCL=x -8J---(
23). However, A2. D4' is determined according to Table 1 below.

Table 1 When the above data is displayed on a graph, the 1st Ω diagram (8)
It becomes OO rough as shown in . However, the first horizontal sleeve displays the group number, and the scale is in increments of "5" up to "33" when n=3, and when n=4. In the case of n-5, the scale is in increments of "5" up to 25". Also, the vertical axis indicates X, and the number of dots between LCL and UCL is fixed, and the numerical values indicate LCL, CL, and UCL. Then, the variation R for each group is RJ = X maw X + nln ”'・
・'''' (24), the total average value R for each group of the variation R is shown, and the upper and lower control limit lines UGL are UCL=D4R (26).

However, D4 is determined from Table 1 above. When the above data is displayed in a graph, it becomes a graph as shown in Figure 1O (B).

Further, when the data processing mode ■1 is selected manually (step S2), fl, Pt173 calculates the logging data in the memory unit 61 (step 515),
A selected specific magnetization characteristic value (for example, the magnetic head 211
A histogram of Φr) at the location measured by is displayed on the display 68 (step 516).

In this case, the first precondition is to set the maximum number of classes on the horizontal axis as “
10" and automatically set the range of the vertical axis to three ways: 80, 40, 20. Furthermore, the scale of the horizontal axis is X□X + X
Display the value of m l n. Then, for classification, the number of classes k is kLfff...
(27), the step width is 11M, the average value X, and the standard deviation 0 are determined by (30). When data are substituted into the above equations (27) to (30) and displayed on a graph, a graph as shown in FIG. 11 is obtained.

In the above embodiment, the magnetic stripe section 3 of the magnetic card 300
The magnetic sensor 400 as a differential side magnetic head as shown in FIG. 13 can be used to measure the magnetization characteristics of the disk surface of the flexible disk. That is, FIG. 12 shows the flexible disk 3
21 shows how the magnetic thin film of No. 21 is inspected, and the b11 air sensor 400 is placed close to the head window portion 322 of the jacket 320 in which the flexible disk 321 is built to measure the magnetization characteristics of the disk surface. .

FIG. 13 shows a perspective structure of the magnetic sensor 400,
Multi-channel magnetic head sections 411 to 419 are provided for detecting magnetization characteristics, and the magnetic head section 4
11 to 418 are 14th sectional views taken along line XX in FIG. 13.
A magnetic head consisting of a magnetic core 431 around which a primary coil 432 and a secondary coil 433 are wound as shown in the figure (^) is built-in. Also, in the magnetic head section 419 (cancellation head section), there is a
A magnetic head (cancellation head) consisting of a cancellation core 441 around which a primary coil 442 and a secondary coil 443 are wound as shown in Figure (B) is built-in. Also,
Each of the magnetic head sections 411 to 418 corresponds to the magnetic head detection side of the magnetic sensor 200 described above, and the magnetic head section 419 corresponds to the magnetic head non-detection side of the magnetic sensor 200. That is, in this magnetic sensor 400, the detection side magnetic heads of the FIU property measuring sections 201 to 208 described above are provided in the magnetic head sections 411 to 418, respectively, and the magnetic head section 419 serves as the non-detection side magnetic head. Furthermore, the magnetic head section 41 of the magnetic sensor 400
A notch 420 is provided on the end face of the case on the 9 side to avoid interference due to contact with the end of the jacket 320.

By using the magnetic sensor 400 having such a configuration, the magnetization characteristics of the flexible disk 321 can be measured in a line at eight locations simultaneously using substantially the same block configuration as in the above embodiment. However, in this embodiment, since the magnetic core and the cancel core are not integrated, the output of the cancel head 419 is transmitted to each magnetic head 411.
The outputs of ~4!8 are individually input to differential amplifiers, differentially amplified, sequentially switched by the multiplexer 24, digitized, and stored. That is,
The output of the cancel head 419 will be used in common. Further, the distribution characteristics of the measurement results are displayed on the display 68 as shown in FIG. Further, by rotating the flexible disk 321 by a predetermined amount, the magnetization characteristics of the entire surface can be measured. Further, if the idea of shunting the magnetic core and the canceling core as in this embodiment is applied to the first embodiment, the result will be as shown in FIGS. 23 and 24. XX cross section and Y-Y in Figure 24
The cross sections correspond to Figures 14 (8) and (B), respectively.

By the way, the windings of the magnetic core, primary coil, and secondary coil of the magnetic head l used in this invention are not limited to those shown in FIG. 1 and FIG. 14 (8) (B), but are as shown in FIG. The magnetic core 1 may be bent at the center of the vertical axis or the center of the horizontal axis, or the primary coil 30 may be wound around the connecting arm IC of the magnetic core 1 as shown in FIG. Also, as shown in Figure 17, there is a magnetic core! The primary coils 31 to 34 may be wound in series around each arm of the magnetic core 40, 41, and a secondary coil may be wound, for example, overlapping the primary coils 31 and 34, as shown in FIG. The magnetic core 4 is separated and magnetically shielded with a shielding material 42.
The primary coil 43 and the secondary coil 44 may be wound around the magnetic core 41, and the primary coil 45 and the secondary coil 46 may be wound around the magnetic core 41. As shown in FIG. 19, the magnetic cores 50 and 51 may be completely separated, and a primary coil and a secondary coil may be wound around each magnetic core 50 and 51, respectively. Furthermore, as shown in FIG. 20, a primary coil 601 is wound around a plate-shaped magnetic core 600, and C-shaped magnetic cores 602 and 603 are connected to both ends of the magnetic core 600, respectively. The secondary coils 604 and 605 may be wound. Furthermore, in the above description, a low frequency triangular wave is applied to the primary coil, but a sine wave or the like may also be applied. Although magnetic cards and flexible disks were measured in the above embodiments, the measuring device of the present invention can also be applied to 5N tapes, SL disks, magneto-optical disks, and the like. Furthermore, although the above-described magnetic sensor is configured to have an eight-channel magnetic head section, the number of channels may be arbitrary. Furthermore, in the other embodiment shown in FIG. 13, the position of the cancel head portion 419 need not be limited to the vicinity of the notch portion 420.

(Effects of the Invention) As described above, according to the magnetization characteristic measuring device of the present invention, magnetic printing is performed on the device, IIf! By simply setting the magnetic thin film part of a magnetic tape, flexible disk, magnetic disk, magnetic card, etc., you can measure the distribution of the magnetization characteristics of the magnetic thin film at once (multi-point high-speed measurement), and also make pass/fail judgments on the magnetization characteristics. This has the advantage of saving labor in the inspection process since it is displayed on a display screen or with a buzzer sound. Furthermore, since the measurement method uses a channel switching method in the magnetic head, the magnetic thin film can be excited with a low frequency repetitive signal, and there is an advantage that the object to be inspected is not affected by eddy currents. In addition, it has the advantage of non-destructive measurement as it can directly measure the object to be inspected as it is, making it possible to measure absolute values when testing the magnetization characteristics of magnetic stripes, disk media, etc.
This has the advantage of clarifying the criteria for evaluating the compatibility of the media.

Furthermore, by adding a moving mechanism such as a stepping motor or a rotary drive device, it is possible to measure the distribution state of magnetization characteristics on the entire stripe or disk surface, and the quality is displayed according to preset standards: Quality Standards It has the advantage of being easy to standardize.

[Brief explanation of drawings]

1 and 2 are block configuration diagrams of a magnetization characteristic measuring device that is an embodiment of the present invention, FIG. 3 is an external view of a magnetic sensor as a differential magnetic head, and FIG. 4 is a differential magnetic A diagram showing how to use a magnetic sensor as a head, Figure 5 is a diagram showing the state of the magnetic head and magnetic field, Figures 6 and 7 are characteristic diagrams of magnetization states, and Figure 8 is a magnetization characteristic measuring device. 9 to 11 and 15 are diagrams showing graphs displayed on the display, and FIGS. 12, 13, 23, and 24 are operation flowcharts for the differential magnetic head FIG. 14 is a diagram showing another embodiment of the magnetic sensor (
^) is a cross-sectional view taken along line X-X in Figures 13 and 24, Figure 14 (B) is a cross-sectional view taken along Y-Y in Figures 13 and 24, and
Figures 6 to 20 are diagrams showing other structures of the magnetic head;
Figure 1 is a diagram showing the state of a magnetic tape, Figure 22 is a diagram explaining a general method of detecting magnetization characteristics, Figures 23 and 24.
The figure shows a modification of the magnetic sensor as a differential magnetic head in FIGS. 3 and 4, and FIGS. 25(A) to 25(E) are timing charts of signals of each part of the measurement data converter. . 1...Magnetic head, 2.3...Primary coil, 4.5
...Secondary coil, 10,11,13.19...Amplifier, 12...Differential amplifier, 14...Sample and hold circuit, 15...A/D converter, 17...Parallel person Output interface, 18... Triangular wave generation circuit, 21... Measured data converter, 24... Multiplexer, 29... Keyboard, 60... Measured data analyzer, 68... Display, 80...・Clock pulse oscillator, 81...Counter, 82...ROM
, 83...D/A converter, 200,400
...Magnetic sensor, 201-208-... Magnetism measuring section. Applicant's representative Yasu Kata Sancha 6 hard cup' Sheep 7 times AX Magnetic card Hanawaka 5 adult bird I Figure 9 Figure 10;:: Zej 1 χ waste aX →- /4s Figure ff Tea 12 Item f3 T2 (,4) CB>No. P4
Nippon Tetsu 1 Sk.

Claims (2)

[Claims] (1) A differential magnetic head that integrates multiple magnetic cores and at least one cancellation core in a line shape to simultaneously measure multiple locations on a magnetic thin film, and excite this differential magnetic head with a repetitive signal. excitation signal generating means for generating an excitation signal; and measurement data converting means for sequentially sampling a plurality of differential output voltages from the differential magnetic head located on or near the magnetic thin film to be measured and converting them into digital values; An apparatus for measuring magnetization characteristics of a magnetic thin film, comprising measurement data analysis means for sequentially storing digital values converted by the measurement data conversion means and calculating magnetization characteristic values of the magnetic thin film at the plurality of locations. (2) The apparatus for measuring magnetization characteristics of a magnetic thin film according to claim 1, wherein the frequency of the repetitive signal is about 1 to 10 Hz.