JP2002237021A - Magnetic recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic recording medium including specified information written beforehand during production. SOLUTION: The magnetic recording medium is provided with a nonmagnetic base film 21, and a magnetic film formed on the base film 21. In this case, first and second magnetic films 22 and 23 respectively having specified lengths in the longitudinal direction of the base film 21 and first and second magnetic characteristics are formed and arranged to have specified patterns alternately, and information is recorded beforehand based on the patterns.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording medium in which a magnetic layer is formed on a film-like substrate, and in particular, by changing the characteristics of the magnetic layer in accordance with the position of the film when forming the magnetic layer, The present invention relates to a magnetic recording medium on which information is recorded.

[0002]

2. Description of the Related Art Conventionally, a magnetic tape has been most widely used as a recording medium used in a magnetic recording / reproducing apparatus.
Further, the recording density of magnetic tapes has been improving year by year, and accordingly, oxide tapes, metal tapes, and thin film tapes have been supplied.

[0003]

When a magnetic tape is produced, for example, a lot number is usually determined and recorded. However, these numbers are usually recorded directly on the magnetic tape. In order to record information or the like, it is necessary to use a magnetic recording device to record information using a magnetic head, which requires a lot of man-hours. For this reason, such information is dealt with by printing it on a cassette case incorporating a magnetic tape, etc., but this also needs to be done one by one, which is very troublesome. there were.

Accordingly, an object of the present invention is to solve the above-mentioned problems and to provide a magnetic recording medium in which predetermined information is written in advance during the production of the magnetic recording medium.

[0005]

According to another aspect of the present invention, there is provided a magnetic recording medium including a non-magnetic base film and a magnetic film formed on the base film. In the above, a first magnetic film having a predetermined length in the longitudinal direction of the base film, having a first magnetic characteristic, and a second magnetic film having a second magnetic characteristic are alternately formed in a predetermined pattern. Wherein the information is recorded in advance by the pattern.

[0006]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. <First Embodiment> FIG. 1 is a top view showing a magnetic recording medium according to the present invention. The magnetic recording medium 20 is a thin film (evaporated) tape in which a magnetic layer 22 and a magnetic layer 23 having different magnetic properties are arranged on a base film 21 in a predetermined shape. Symbols A to G in FIG.
Correspond to the periods A to G shown in FIG.

Next, an apparatus for manufacturing the magnetic recording medium of the first embodiment will be described. FIG. 2 is a schematic configuration diagram of the oblique deposition apparatus. In FIG. 2, reference numeral 30 denotes an oblique evaporation device. The unwind roll 2, the take-up roll 3, the guide rolls 4, 5 and the cooling can roll 7 are arranged at predetermined positions in the vacuum chamber 1 of the oblique deposition apparatus 30 so as to be rotatable. The non-magnetic substrate having a predetermined width wound around the unwinding roll 2, that is, the base film 6,
Pulled out, guide roll 4, cooling can roll 7,
It is wound on the winding roll 3 via the guide roll 5. The base film 6 runs in the direction of the arrow in the figure from the unwinding roll 2 to the winding roll 3.

A cooling device (not shown) is provided inside the cooling can roll 7 to prevent deformation of the base film 6 due to a rise in temperature when a magnetic material is deposited on the base film 6. A crucible 8 containing a magnetic material 11 is disposed below the cooling can roll 7, and a heating device for melting and evaporating the magnetic material 11 is provided on a side wall of the vacuum chamber 1, for example, a pierce type. An electron gun 12 is provided.

Further, masks 9 and 10 are arranged in the vicinity of the outer peripheral surface of the cooling can roll 7, and the mask 9 allows the maximum incident angle θ of the vapor flow of the magnetic material to the base film 6.
max is regulated, and the mask 10 allows the minimum incident angle θmi
n is regulated. Atmospheric gas is introduced into the vacuum chamber 1 by discharging gas from a nozzle 16 from a gas source (not shown) via a pipe and a mass flow controller 17.

While the base film 6 is traveling on the outer peripheral surface of the cooling can roll 7, the base film 6 evaporates within a range of the maximum and minimum incident angles set at a predetermined angle (this range is called an evaporation opening). The magnetic material thus deposited adheres to the surface of the base film 6, and a magnetic film is formed. At this time, the magnetic characteristics of the obtained magnetic film are determined by the maximum incident angle θmax and the minimum incident angle θmin of the vapor flow of the magnetic material. Generally, the maximum incident angle θmax = 90 °, the minimum incident angle θm
in is set to 40 °.

The electron beam 13 emitted from the pierce type electron gun 12 is controlled by a deflection magnet 1 arranged close to the crucible 8 and applying a deflection magnetic field to the trajectory of the electron beam 13.
4 and the deflection magnet 15 in the pierce type electron gun 12. The irradiation position of the electron beam 13 is located at the center of the crucible 8 and is scanned at a predetermined cycle in the width direction of the base film 6 to melt and evaporate the magnetic material 11 in the crucible 8. In addition, the straight electron beam emitted from the electron gun 12 is transmitted to the crucible 8 using only the deflection magnet 15 in the electron gun 12 without installing a deflection magnet close to the crucible 8.
There is also a method of scanning inside.

Using this oblique evaporation apparatus, a magnetic recording medium of the first embodiment was manufactured. Co (cobalt) is used as the magnetic material 11 to be deposited, and O ₂ (oxygen) is placed in a vacuum chamber.
Gas is introduced and PET (polyethylene terephthalate)
A CoO magnetic film was formed on a base film 6 made of. At this time, the PET base film was placed at 60 cm / mi.
n, and the amount of oxygen gas introduced into the vacuum chamber was controlled using a piezo actuator type mass flow controller having a high response speed.

FIG. 3 is a graph showing pressure conditions for oblique deposition when manufacturing the first embodiment of the magnetic recording medium of the present invention. Here, as shown in FIG. 3, the oxygen gas pressure at the time of vapor deposition is set to 2.5 × 10 ⁻² Pa (hereinafter, also simply referred to as high pressure) and 1.1 × 10 ⁻² Pa (hereinafter, simply referred to as low pressure). (Also referred to as pressure) to form a magnetic film. Following the low pressure period G, a 0.5 second high pressure period A, a 0.5 second low pressure period B, a 1.0 second high pressure period C, a 0.5 second low pressure period Period D was a high pressure period E of 0.5 seconds, and then period F was a normal condition of low pressure.

The thickness of the obtained magnetic film is 0.18 μm during the high pressure period and 0.16 μm during the low pressure period.
m. As a result of measuring the magnetic characteristics, the periods A, C, E
In the (high pressure period) magnetic layer, the coercive force (hereinafter, also simply referred to as Hc) was 1500 Oe, and the magnetization (hereinafter, also simply referred to as Ms) was 350 emu / cc. On the other hand, in the magnetic layers in the periods B, D, F, and G (low pressure period), Hc is 1400 Oe
s was 450 emu / cc. Then, a 10 nm thick DLC (Diamond Like) is formed on the magnetic film.
Carbon) A protective film was formed, a fluorine-based lubricant was further applied to a thickness of 2 nm, a back coat was applied to the back surface of the base film on which the magnetic film was not formed, and slit to 1/4 inch with a slitter. The magnetic recording medium (magnetic tape) of the example was obtained.

After that, using this magnetic tape,
A predetermined scene was recorded with a commercially available DVC video camera having a relative head speed of 10.2 m / sec. The shortest recording wavelength at this time is 0.49 μm. Next, the reproduced waveform was measured. FIG.
FIG. 3 is a diagram showing a reproduction waveform in the first embodiment of the magnetic recording medium of the present invention. In the reproduced waveform envelope of the magnetic tape portion corresponding to the periods A to G of FIG. 3 shown in FIG. 4, the output of the region corresponding to the periods A, C, and E is E1, and the periods B, D, F, and G are output. The output of the area corresponding to
And the ratio of E1 to E0 (E1 / E0) was 0.9.

FIG. 5 is a diagram showing an information detection circuit for reproducing the first embodiment of the magnetic recording medium of the present invention and its output signal. 5A shows an information detection circuit 33 including a detection circuit 31 and an integration circuit 32.
(B) shows an output obtained by inputting the reproduced waveform envelope shown in FIG. Here, the times of the areas A, B, C, D, and E are 0.49, 0.49, 0.98, 0.49, and 0.49, respectively.
msec. The integration circuit has a carrier frequency (20.8 MHz) of 20 dB with respect to the pass band.
A circuit having a characteristic of attenuating was used.

The basic unit time constituting the periods A, B, C, D, and E shown in FIG.
Periods A, B, having a time of seconds or a multiple of 0.5 seconds
Some information can be recorded by sorting to C, D, and E. For example, periods A, B, C, D, E
Are combined as shown in Table 1 below, and
Numerical information can be recorded by corresponding to numbers from 9 to 9.

[0018]

[Table 1]

FIG. 6 shows the pattern. FIG. 6 is a diagram showing information in the first embodiment of the magnetic recording medium of the present invention. In FIG. 6, the left numerical value is expressed corresponding to the right pattern. The basic unit time of 0.5 seconds in the periods A, B, C, D and E corresponds to a recording wavelength of 10 mm. DVC
Since the shortest recording wavelength of video is 0.5 μm, it is effective when the recording wavelength of the basic unit is long.

Next, the output E1 was changed by changing the characteristics of the areas corresponding to the periods A, C, and E, and the presence or absence of an error in the reproduced image when the recorded image was reproduced was examined. Table 2 shows the results.

[0021]

[Table 2]

From this, if E1 / E0 is smaller than 0.70, an error occurs in the reproduced image.
By setting E0 to a predetermined value, predetermined information can be recorded without affecting the reproduced image at all. The amount of gas introduced will be changed from now on, and the magnetic properties of the magnetic film of the magnetic tape,
By changing the film thickness, predetermined information is recorded on a magnetic tape, and thereafter, an image is magnetically recorded on the tape,
It can be seen that predetermined information recorded as a change in the magnetic characteristics can be detected from the reproduction envelope. Also, E1 /
By setting E0 to a predetermined value, it is possible to detect the reproduced image without causing an error.

As a result of measuring the surface reflectance of the magnetic tape of the first embodiment with light having a wavelength of 600 nm, 13% was obtained in the areas corresponding to the periods A, C, and E, and corresponding to the periods B, D, F, and G. In the area, it was 20%. A commercially available DVC video is mounted with a small semiconductor laser with a wavelength of 670 nm and an output of 3 mw and a light receiving element, and the reflectance of the running tape is measured at an incident angle of 45 °, and the periods A, B, C,
Regions corresponding to D, E, F, and G were respectively detected.
From now on, by changing the amount of oxygen gas introduced when producing a magnetic tape, the characteristics and thickness of the magnetic layer are changed,
As a result, it can be seen that information can be recorded on the magnetic tape, and that the information can be detected by a difference in reflectance. In addition, as a base film, PEN (polyethylene naphthalate), PI (polyimide), PA (polyamide) and the like can also be used.

<Second Embodiment> As in the case of the magnetic tape of the first embodiment, an oxygen gas is introduced to evaporate Co using the oblique deposition device 30 shown in FIG.
A magnetic film was formed. Here, oxygen gas was introduced into the vacuum chamber 1 by the gas introduction nozzle 16 and the pressure was increased to 1.1 × 10
^-2 Pa was fixed. 6 base film made of PET
A film was formed by running at 0 cm / min. At this time, the running speed of the base film was changed according to the period.

FIG. 7 is a graph showing the running speed of the substrate during oblique deposition when manufacturing the second embodiment of the magnetic recording medium of the present invention. That is, successive periods G, A,
In B, C, D, E, and F, in a period A of 0.5 seconds, a period C of 1 second, and a period E of 0.5 seconds, the traveling speed of the base film is set to 0.8 m / min, A period B of seconds,
In the period D of 0.5 seconds, and the periods F and G before and after, the running speed was adjusted to be 0.6 m / min.

The magnetic film in the regions corresponding to the periods A, C, and E was 0.12 μm in thickness, Hc was 1300 Oe, and Ms was 390 emu / cc. On the other hand, the magnetic film in the regions corresponding to the periods B, D, F, and G has a thickness of. 16μ
m, Hc is 1400 Oersted, Ms is 450
emu / cc. Next, a thickness of 10 n is formed on the magnetic film.
m DLC protective film is formed, a fluorine-based lubricant having a thickness of 2 nm is applied thereon, and a back coat is applied to the back surface of the base film on which the magnetic film is not formed.
A magnetic tape was obtained by slitting to an inch width.

The magnetic tape is provided with a DV as in the first embodiment.
Recording and reproduction were performed with a C video camera. As a result, similarly to the first embodiment, in the second embodiment, the reproduced waveform envelope shown in FIG. 4 is obtained, and the same signal processing as in the first embodiment is performed. Signal was obtained. Thus, by changing the running speed of the base film, regions having different magnetic properties and film thicknesses can be provided on the magnetic tape. As in the case of the first embodiment, these regions are appropriately combined to obtain a predetermined region. Information can be pre-written on magnetic tape.

As a result of measuring the surface reflectivity of the magnetic tape of the second embodiment with light having a wavelength of 600 nm, the area corresponding to the periods A, C and E is 16%, and the regions B, D, F and G are corresponding. In the area, it was 20%. As in the first embodiment, the reflectance of the running tape was measured, and the areas corresponding to the periods A, B, C, D, E, F, and G could be respectively detected from the differences in the reflectance. From this, it can be seen that by changing the running speed of the base film when manufacturing the magnetic tape, the characteristics of the magnetic layer are changed, whereby information can be recorded on the magnetic tape, and the information can be detected by the difference in reflectance. .

<Third Embodiment> As in the case of the magnetic tape of the first embodiment, the oblique vapor deposition device 30 shown in FIG. 2 is used to introduce oxygen gas to evaporate Co, thereby forming CoO on the base film.
A magnetic film was formed. Here, oxygen gas was introduced into the vacuum chamber 1 by the gas introduction nozzle 16 and the pressure was increased to 1.1 × 10
^-2 Pa was fixed. 6 base film made of PET
The film was formed by running at 0 cm / min. At this time, the output of the electron gun for dissolving Co was changed as shown in FIG.

FIG. 8 is a graph showing the output of an electron gun in oblique deposition when the third embodiment of the magnetic recording medium of the present invention is manufactured. As shown in FIG. 8, continuous periods G,
In A, B, C, D, E, and F, a period of 0.5 seconds A,
In the period C of 1 second and the period E of 0.5 second, the output of the electron gun for melting the Co material is reduced by 20% from the predetermined output.
In a region B of 0.5 seconds, a region D of 0.5 seconds, and periods F and G before and after, a magnetic film was formed with a predetermined electron gun output. As a result, the magnetic film in the regions corresponding to the periods A, C, and E has a thickness of 0.13 μm, and Hc is 1550 Oe, M
s was 330 emu / cc.

On the other hand, the magnetic film in the regions corresponding to the periods B, D, F, and G has a thickness of. Hc was 1400 Oe and Ms was 450 emu / cc. next,
A DLC protective film having a thickness of 10 nm is formed on the magnetic film, a fluorine-based lubricant having a thickness of 2 nm is applied thereon, and a back coat is applied to the back surface of the base film on which the magnetic film is not formed. A magnetic tape was obtained by slitting to a 1/4 inch width. As in the first embodiment, D
Recording and reproduction were performed with a VC video camera.

As a result, similarly to the first embodiment, in the third embodiment, the reproduced waveform envelope shown in FIG. 4 is obtained, and the same signal processing as in the first embodiment is performed.
The signal shown in FIG. Thus, by changing the output of the electron gun when manufacturing the magnetic tape, regions having different magnetic properties and film thicknesses can be provided on the magnetic tape, and these regions are appropriately combined as in the first embodiment. This allows predetermined information to be written on the magnetic tape in advance.

As a result of measuring the surface reflectance of the magnetic tape of the third embodiment with light having a wavelength of 600 nm, 12% was obtained in the areas corresponding to the periods A, C, and E, and corresponding to the periods B, D, F, and G. In the area, it was 20%. As in the first embodiment, the reflectance of the running tape was measured, and the areas corresponding to the periods A, B, C, D, E, F, and G could be respectively detected from the differences in the reflectance. From now on, by changing the output of the electron gun when manufacturing the magnetic tape, the characteristics and thickness of the magnetic layer can be changed, so that information can be recorded on the magnetic tape and the information can be detected by the difference in reflectance. I understand.

[0034]

As described above in detail, according to the magnetic recording medium of the present invention, the first magnetic film having the predetermined length in the longitudinal direction of the base film and having the first magnetic characteristics A second magnetic film having a second magnetic characteristic is alternately formed and arranged in a predetermined pattern, and information is recorded in advance by the pattern, so that predetermined information is written in advance during the production. There is an effect that it is possible to provide a magnetic recording medium embedded therein.

[Brief description of the drawings]

FIG. 1 is a top view showing a magnetic recording medium according to the present invention.

FIG. 2 is a schematic configuration diagram of an oblique deposition apparatus.

FIG. 3 is a graph showing pressure conditions for oblique deposition when manufacturing the first embodiment of the magnetic recording medium of the present invention.

FIG. 4 is a diagram showing a reproduction waveform in the first embodiment of the magnetic recording medium of the present invention.

FIG. 5 is a diagram showing an information detection circuit for reproducing the first embodiment of the magnetic recording medium of the present invention and an output signal thereof.

FIG. 6 is a diagram showing information in the first embodiment of the magnetic recording medium of the present invention.

FIG. 7 is a graph showing a traveling speed of a substrate in oblique deposition when manufacturing a second embodiment of the magnetic recording medium of the present invention.

FIG. 8 is a graph showing the output of an electron gun in oblique deposition when manufacturing the third embodiment of the magnetic recording medium of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Vacuum tank, 2 ... Unwinding roll, 3 ... Winding roll, 4
... guide roll, 5 ... guide roll, 6 ... base film (substrate), 7 ... cooling can roll, 8 ... crucible, 9 ...
Mask: 10: Mask, 11: Magnetic material, 12: Pierce type electron gun, 13: Electron gun, 14: Deflection magnet, 15
... deflecting magnet (in the electron gun), 16 ... nozzle, 17
... Mass flow controller, 20 ... Magnetic recording medium (magnetic tape), 21 ... Base film, 22 ... Magnetic layer, 23
... magnetic layer, 30 ... oblique deposition device, 31 ... detection circuit, 32
... an integrating circuit, 33 ... an information detecting circuit.

Claims (1)

[Claims] 1. A magnetic recording medium having a non-magnetic base film and a magnetic film formed on the base film, wherein the magnetic recording medium has a predetermined length in a longitudinal direction of the base film,
The first magnetic film having the magnetic property of 1 and the second magnetic film having the second magnetic property are alternately formed and arranged in a predetermined pattern, and information is recorded in advance by the pattern. A magnetic recording medium characterized by the above-mentioned.