JPH0386912A - Magnetic recording and reproducing method for information, magnetic recording medium used for the same, manufacture of the same and magnetic recorder - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Usage field on M beam]

The present invention relates to a magnetic recording and reproducing method for magnetically recording and reproducing digital information while controlling tracking of a magnetic head, a magnetic recording medium used therein, a method for manufacturing the same, and a magnetic recording apparatus for recording and reproducing the same.

[Conventional technology 1] In a conventional magnetic recording medium (magnetic disk) in which digital information is recorded by a magnetic head, the eccentricity of the magnetic recording medium is made sufficiently small, the track width is made sufficiently wide, and the accuracy of the magnetic recording device mechanism is This method reduces the relative positional error between the magnetic recording medium and the magnetic head by increasing the After sputtering a magnetic film onto the substrate and initializing it, the substrate is initialized one by one with a magnetic head using a servo writer or magnetic recording device. [Problems to be Solved by the Invention] In order to increase the density by narrowing the recording track width of a magnetic recording medium, it is necessary to increase the processing precision of the mechanical parts of the magnetic recording medium and magnetic recording device. However, this reduces the productivity of the recording medium (magnetic disk), and also requires ultra-m density for the mechanical part of the magnetic recording device, making it extremely difficult to use as a magnetic recording device in terms of stability, price, etc. It becomes a big deal. In addition, in the past, it was not possible to create a replica of fixed computer-specific information on a magnetic disk in advance, so when it came to personal computer software, it was necessary to purchase software that was pre-recorded on a floppy disk and use it from that floppy disk. The complicated process of transferring information to a magnetic disk was necessary. As the scale of the software increases, the number of floppy disks increases into the dozens, which reduces the operability of the device and makes it difficult for the user to use. Moreover, magnetic disk media requires initial magnetization by sputtering a magnetic film on a disk substrate, such as an aluminum substrate, and then initializing the disk one by one with a magnetic head using a servo writer or magnetic recording device. It was difficult to make large-scale copies of disk media. On the other hand, in magnetic disks (floppy disks) where digital information is recorded using a magnetic head while optically tracking it, guide grooves are provided in advance on the magnetic medium. When recording information, a method has been proposed in which the magnetic head is guided optically by relying on this guide groove, and information is recorded magnetically (Nikkei Electronics, 1988).
9.5°No, 455). An object of the present invention is to perform highly accurate tracking control of a magnetic head by preforming magnetically detectable servo pits on a magnetic recording medium, thereby magnetically recording information with high reliability and high density. The object of the present invention is to provide a recording and reproducing method that enables recording and reproducing. Another object of the present invention is to provide a magnetic recording medium that enables highly accurate tracking control of a magnetic head by preforming magnetically detectable servo pits and data pits, and that can be easily reproduced. The purpose is to provide a method. Another object of the present invention is to provide a magnetic recording device equipped with a tracking signal detection system that can magnetically detect tracking signals using servo pits provided in advance on a magnetic recording medium.

[Means to solve the problem]

In the present invention, a magnetic recording medium is provided with magnetically readable servo pits that are preformed and have magnetic properties different from those of the recording magnetic film, and a magnetic head is attached to the edges of these servo pits. A tracking signal or synchronization signal is generated from the generated magnetic flux distribution (leakage magnetic field).
It is characterized by magnetically detecting a preformat signal such as an address signal, and servo-controlling the position of the magnetic head using the detected tracking signal to magnetically record or reproduce information along the center of the track. shall be. The magnetic recording medium of the present invention has magnetically readable meandering servo pits, synchronous pits, track address pits, and data pits preformed on the magnetic recording medium, and these pits are locally formed using a recording magnetic film. This is a magnetic recording medium that has a magnetic structure with different magnetic characteristics, for example, the saturation magnetization is smaller than other parts. According to one feature of the present invention, the preformed pits are formed by locally removing the recording magnetic film. According to another feature, the preformed pits are formed by locally removing the base film of the recording magnetic film. It can be read magnetically by detecting it with a magnetic head floating above. For example, tracking servo pits are provided at predetermined intervals along the track.
Consisting of at least one pair of pits that are preformed in a meandering manner with respect to the center of the track, the tracking signal is detected by comparing the reproduction signal of the magnetic head obtained when the magnetic head passes through the pair of wobble pits. be done. Further, the magnetic recording medium of the present invention has a first area (ROM area) in which magnetically reproducible information is provided in advance, and a second area (ROM area) in which a user can magnetically record and reproduce information.
RAM area). Although the information in the first area (ROM area) is magnetically reproducible, it can be copied, and this first area (ROM area) contains information specific to the device used, such as computer-specific software. It is preferable to record fixed information. According to one feature, the first area (ROM area) and the second area
(RAM area) are angularly divided and mixed. In the first area (ROM area), magnetically reproducible information (ROM information) is recorded! It is preformed with partially different magnetic properties from the magnetic film. Also,
In the first area (ROM area), a large number of preformed magnetically reproducible servo marks with partially different magnetic properties from the recording magnetic film are provided periodically along the track, and these servo marks are provided periodically along the track. The magnetically reproducible information (ROM information) is preformed between the marks. According to another feature, the second area (RAM area) also has magnetically reproducible servo marks preformed with partially different magnetic properties from the recording magnetic film at regular intervals along the track. A large number of servo marks are provided, and the space between these servo marks serves as an information recording area for the user to magnetically record information.

[Effect]

According to the present invention, a magnetic recording medium preformed with servo pits having partially different magnetic properties from that of the recording magnetic film is used as a mark for detecting a tracking signal, and localized marks formed at the edges of these servo pits are used. Since a tracking signal is detected from the magnetic field (leakage field) by a magnetic head flying above the magnetic recording medium, the tracking signal can be detected with a high S/N using only the magnetic head, and it is also compact. According to the present invention, servo marks (servo pits) having different magnetic properties from the recording magnetic film are preformed, and although these preform pits are magnetically detectable, they can be reproduced, and the original The magnetic recording medium of the invention can be produced in large quantities at low cost. Further, according to the magnetic recording medium of the present invention, there is a first area (ROM area) in which magnetically reproducible information is provided in advance, and a second area (RAM area) in which the user can magnetically record and reproduce information. This first region (
By recording fixed information specific to the device being used, such as computer-specific software, in the ROM area, there is no need for the user to magnetically copy software programs and the like from the floppy disk to the magnetic recording medium. Moreover, even though the information in the first area (ROM area) is magnetically reproducible, it is replicable, and the same information (
Magnetic recording media preformed with servo information, synchronization information, address information, and ROM information can be produced in large quantities with high accuracy. In addition, the first area (ROM area) and the second area (R
By providing a large number of servo marks periodically along, for example, concentric circles or spiral tracks in the AM area, the magnetic flux distribution generated in the servo marks is magnetically detected with a magnetic head to obtain a tracking signal. While controlling the servo position of the magnetic head, information can be recorded in the second area (RAM area) or in the first area (ROM area).
area) information can be read out.

【Example】

The construction drawing shows a magnetic recording medium according to one embodiment of the present invention, and FIGS. A tracking pit and a clock pit are shown. In FIG. 1, the magnetic recording medium base l is made of glass, resin, or aluminum, and its recording surface has a structure shown in FIG.
As shown in a) to (C), a large number of tracking servo pits 3.3' and 4.4' are periodically printed along concentric or spiral tracks 2 and 2' by etching or injection shaping. It has been renovated. More preferably, the preform is performed by removing the magnetic film by ion milling or reactive ion etching. In this way, the servo mark consists of at least a pair of bits 3.4 (3', 4) preformed to the left and right with respect to the center line of the tracks 2, 2'.
”).The tracking servo pit can also be shared between adjacent tracks 2 and 2' as shown in FIG. 2(b).Also, as shown in FIG. 2(c), the tracking servo pit The pits may be formed widely so that they partially overlap when viewed in the traveling direction of the tracks, that is, in the circumferential direction.The pits 35 and 35' in FIG. These are clock pits provided along the center line, and like the tracking servo pits, these clock pits are also preformed by removing the magnetic film by ion milling or reactive ion etching. 4,35°3',
4' and 35' are elongated in a direction perpendicular to the data recording direction (track direction), as shown in FIGS. It is preferable that the magnetic gap is approximately the same as l1li)D of the magnetic gap). In addition, these preform pits 3, 4, 35° 3'
, 4', 35' may be provided at an angle with respect to the tracks 2, 2', as shown in FIG. recorded and played back. This eliminates crosstalk between tracks 2 and 2', making it possible to further narrow the track pitch. A magnetic recording thin film (ferromagnetic film) 5 is formed on this medium base 1, and bits 3.3'35°4.4'
, 35', there is no magnetic recording thin film in the preform pits. While rotating the magnetic recording medium (magnetic film) 5, the entire surface is initially magnetized by a magnet. The magnetization direction 6 coincides with the disk circumferential direction, that is, the data recording direction. FIG. 4 shows a cross-sectional view of a preform pit 20, such as a servo pit 3.3', 4.4' or a clock pit 35.35', viewed along the circumferential direction of the disk, that is, the data recording direction. FIG. 4(a) shows the preform pit 20 connected to the magnetic head 1.
0 shows the diagram being played. In the figure, numeral 5 indicates a recording magnetic film formed on the substrate 1. This magnetic recording thin film (m-type film) 5 is magnetized in one direction 6 due to initial magnetization, and there is no leakage magnetic field at a location away from the preform pit 20. However, in the preform pit 20 (13, 3', 4°4', 35, 35'), positive and negative magnetic poles 7, 8 are formed on both walls, and as a result, a magnetic field leaks from both edges of the preform bit 200. Occur. This leakage magnetic field is magnetically read by 35' located on the magnetic recording medium. For example, a magnetic head upper stop positioned above a rotating magnetic disk recording medium flies with a minute flying height of .mu.m or less. FIGS. 4(b) to 4(d) show the magnetic film structure near the preform bit 20. FIG. Fig. 4(b) shows the preform pit 20 13, 3', 4.4'35.35')
This is an example in which the substrate 1 is flat and there is no magnetic film 5 in that portion. In this way, N is applied to both end walls of the preform pit 20.
and S magnetic poles 7 and 8 are formed, and as a result a leakage magnetic field 9 is generated at both edges of the preform pit 20. Figure 4 (
c) is a case where the base 1 of the preform pit 20 is convex. There is no magnetic film 5 in this convex pit portion. FIG. 4(d) shows a case where the preform pit 20 is concave, and similarly there is no magnetic film 5 in this concave pit portion. These preform pits 2
0 13, 3', 4.4', 35°35') is preferably about the same depth as the pit width in the data recording direction.For example, if the thickness of the magnetic film 5 is 0.1 micron, the preform The depth of the pit 20 is 0.1-0.5 micron. Further, the pit length of the preform pit 20 in the data recording direction may be set to 0.5 microns, and the pit width in the disk radial direction may be set to about 1 to 20 microns. Figure 4 (
In any of cases b), (Q), and (d), N and S magnetic poles 7, 8 is formed, resulting in a preform pit 20
A leakage magnetic field 9 is generated at both ends. Magnetism can be detected by detecting the magnetic flux 9 generated from the edge of the preform pit 20 with the magnetic head 10. That is, such a preform pit 20 is scanned by the magnetic head 10, and when the magnetic head 10 passes through the preform pit 20, the magnetic flux 11 formed in the core 13 of the magnetic head 10 is detected by the magnetic coil 12. It can be reproduced magnetically. FIG. 5 shows the intensity of the magnetic flux 11 passing through the magnetic coil 12 when the magnetic head travels through the preform pit 20 in a direction perpendicular to the data recording direction, that is, in the radial direction. A desirable output signal can be obtained by making the size of the magnetic flux 11 in the direction perpendicular to the data recording direction of the magnetic head 10 approximately the same as the width d of the preform pit 20 in the direction perpendicular to the data recording direction. In FIG. 5, the magnetic flux 11 is symmetrical about the pit center, and although the magnitude of the track deviation can be determined from this, the direction of the track deviation cannot be detected. Therefore, in the present invention, preform pits 3.4 (3'4') meandering with respect to the track center on the magnetic recording medium are used as tracking servo pits for detecting the magnitude and direction of track deviation. Figures 2 and 3 can be drawn using Figures 6 and 7 (a) to (c).
Meandering preform pits 3, 4 (3', 4
The operation of detecting a tracking signal from ) will be explained. In FIG. 6, the center of the magnetic head 10 is A, B,
Consider the case of passing along each of C. When the magnetic head passes along the dashed line A, the magnetic head passes over the pit 3, so that the signal detected by the magnetic head is large from the pit 3, while the signal from the pit 4 is small. Therefore, the detection signal shown in Fig. 7(a) is obtained.6 Fig. 7(b) shows that when the magnetic head passes along the solid line B (track center) in Fig. 6, the detection signal shown in Fig. 7(c) is obtained. shows a detected waveform when the magnetic head passes along the two-dot chain line C in FIG. Therefore, the tracking signal indicating the magnitude and direction of the track deviation is the reproduction signal of the magnetic head 10 obtained when the magnetic head 10 passes over the pair of meandering preform pits 3.4 (3', 4'). It is obtained by detecting a sample and finding the difference between the two. Magnetic gap 30 of magnetic head 10
To control the position of coincident with the center of the track,
Tracking control may be performed by moving the position of the magnetic head IO in a direction perpendicular to the data recording direction (radial direction) using the detected tracking signal so that the detected waveform shown in FIG. 7(b) is always obtained. Next, the above-mentioned magnetically detectable tracking servo pits are formed in advance on a magnetic recording medium (for example, a magnetic disk), and these tracking servo pits are used to perform highly accurate tracking control of the magnetic head. A method for magnetically recording and reproducing information will be explained. Figure 8 shows one magnetic head raised (see Figure 4 (a)).
This shows a case where both data recording/reproduction and tracking signal detection can be performed. The concentric or spiral track 2 is divided into a servo area for detecting tracking signals and periodic signals and a data area for recording data, and these servo areas and data areas alternate periodically along the track. There are many. The preform pits (ρ1ts) in these servo areas and the recorded data in the data area are detected in a time-division manner by one magnetic head that scans along the center line of the track. As mentioned above, each servo area has a tracking servo mark for detecting the size and direction of track deviation.
A pair of preform pits 3 and 4 are formed in a meandering manner with respect to the track center on the magnetic recording medium. In each servo area, a clock pit may be preformed along the center line of the track, as shown at 35°35' in FIGS. 2(c) and 3(c). Alternatively, the preform may be tilted with respect to the track as shown in FIG. 3(d). Furthermore, track address pits may be preformed along the center line of the track if necessary. As mentioned above, these preform pits in the servo area have locally different magnetic properties from the recording magnetic film 5, and are formed by removing the magnetic film 5 by, for example, ion milling or reactive ion etching. By detecting the leakage magnetic field generated from both edges of these preform bits with the magnetic head 10,
Read magnetically. The tracking signal is as shown in Figures 6 and 7.
As explained in detail with reference to the drawings, this is obtained by sample-detecting the leakage magnetic field generated from the edges of a pair of wobble pits 3 and 4 preformed in the servo area using the magnetic head 10. While controlling the servo position of the magnetic head 10 based on the detected tracking signal, the magnetic head 10 records or reproduces desired data in the data area between the servo areas along the center line of the track. The magnetic head 10 is supported by a support mechanism (not shown) connected to an actuator (not shown),
By disabling this actuator, it is possible to move in a direction perpendicular to the data recording direction (for example, in the radial direction of the magnetic disk). Therefore, by opening this actuator based on the detected tracking signal, tracking is controlled so that the magnetic head 10 always scans the center of the track, and data is transferred along the center of the track in the data area by the magnetic head 10 under tracking control. Accurately recorded and played back. Note that when the data area is long, it is preferable to hold the tracking signal detected from the wobble pit in the servo area during the data area period. In this embodiment, the magnetic film 5 is a magnetic thin film for in-plane recording, and the data recorded in the data area is recorded in-plane (magnetized in a direction parallel to the magnetic film 5) by the magnetic head 10. 9 and 10 respectively show other examples of track patterns of the magnetic recording medium used in the present invention. In both cases, the track is separated into a servo area for detecting tracking signals and a data area for recording data, and the point that the signal is detected in a time-division manner using one magnetic coil is the same as in the case of Figure 8. can be. Desired data is recorded and reproduced along the track center in the data area between the servo areas by a tracking-controlled magnetic head. In FIG. 9, a pair of circular pits 53 and 54 meandering with respect to the track center are preformed as tracking servo marks in each servo area. On the other hand, in FIG. 10, in each servo area, a pit row 63 with a frequency f1 is located at a position slightly offset from the track center in one direction (perpendicular to the data recording direction, for example, toward the inner circumference). For example, a pit row 64 with a frequency f2 is preformed at a position shifted toward the outer circumference. In FIG. 10, the preform pit rows 63 and 64 are each formed with circular pits, but from the viewpoint of improving the recording density in the track direction and improving the S/N, as mentioned above, it is necessary to It is preferable to preform the pit rows 63 and 64 with long rectangular pits whose length is about the same as the width of the recording area 30 on the magnetic head. FIG. 11 shows pit rows 72 of different frequencies f□t fz.
゜73 was preformed with a rectangular pit. The pit rows of frequencies fyut and f2 can be detected separately by frequency discrimination, so they can be preformed on both sides of the track center at the same time as shown in Fig. 10 and detected at the same time, or as shown in Fig. 11. It is also possible to preform it by shifting it along the track, as shown in the figure, and detect it in a time-division manner. A method for detecting tracking signals from the preform pit arrays of these frequencies fi and f2 will be explained with reference to FIG. A detection signal from the magnetic head 10 scanning along the track is separated by a frequency discriminator 65 into components of frequency f and f2. Each component is amplified by a differential amplifier 66 to obtain a tracking signal. The tracking signal is sent to an actuator that changes the radial position of the magnetic head. When the amplitudes of each component are equal, the magnetic head is located at the center of the track. Next, a method for producing a magnetic recording medium having the above-mentioned preform bits will be explained. FIG. 13 shows a photomask recording device used in the manufacturing method of the present invention. This recording device uses a chrome photomask 13
0 on the magnetic recording medium 1 using ultraviolet laser light. That is, magnetically reproducible ROM data provided in advance in the ROM area, ROM area and/or RAM
A pattern consisting of signals to be preformed such as magnetically reproducible tracking servo marks, clock pits, address pits, etc. in a servo area provided periodically along a track is recorded in the area. In FIG. 13(a), a chrome photomask 130 is fixed to a rotation bearing and rotated. On the other hand, a laser beam such as an argon laser (W=0.45
Micron) LA is intensity-modulated by a light modulator MD according to the signal to be preformed, and has a high NA (for example, NA=0.
When the light is focused by the lens system 93), a circular spot with a diameter of about 0.4 microns is formed on the rotating mask 130. now. Each preform pit 20 constituting ROM data, tracking servo marks, clock pits, and address pits has a long dimension in the disk radial direction, for example, 5 mm.
In terms of microns, a circular spot of 0.4 microns cannot create a vertically long pit. FIG. 13(b) is a diagram for explaining an example of a method for forming vertically long pits. In FIG. 13(a), the optical system is moved linearly in the radial direction of the disk of the photomask 130 on a moving table.
The speed of movement is preferably controlled so that the photomask 130 moves by a distance smaller than the diameter of the light spot, for example, by an amount approximately equivalent to the radius of the light spot, during one rotation of the photomask 130. Then, as shown in FIG. 13(b), the integral value of the amount of light irradiated onto a desired portion of the photomask 130 becomes a uniform rectangle. Now, in order to form a vertically long preform pit of 5 microns with a light spot diameter of 0.4 microns, the amount of movement of the optical system is 0.2 microns/rotation, and 510.2=
In other words, the intensity of the light may be modulated in accordance with the signal to be preformed at a desired timing while the photomask 130 rotates 25 times. The above-mentioned preform pit 20 (tracking servo pits 3 and 4) is
．． 3', 4'...;53,54;63.64
;72,73;Address pit and clock pit35.
35'..., ROM data pit 17 to be described later
The mask 130 on which a pattern consisting of rows of . . . ) is recorded is developed and etched.
is obtained. Using this mask 130, a magnetic recording medium is produced by the processes shown in FIGS. 14 to 17, which are an embodiment of the present invention. FIG. 14 shows an example of a method for producing a magnetic medium in which the magnetic thin film (magnetic film) 5 of each preform pit 20 is removed. In FIG. 14(a), a negative resist 22 is coated on an aluminum or glass disk substrate 1, and the above-mentioned mask 130 is brought into close contact with this photoresist-coated disk substrate 1 for exposure. In FIG. 14(b), after exposing the negative resist 22, the mask 130 is removed and developed, and the resist other than the pit portions 20 is dissolved by the development, but the resist 23 remains only in the pit portions 20. In FIG. 14(c), a magnetic thin film 5 is formed by sputtering on the entire surface of the disk substrate 1 where the resist 23 remains. In FIG. 14(d), the resist 23 on the disk is removed. For example, by removing with a plasma asher or an organic solvent, the magnetic thin film 5 in the pit portions 20 is removed, and a magnetic recording medium without the magnetic film 5 only in the pit portions 20 can be created. Also, the 14th
In Figure (d), the magnetic film 5 coated in a raised manner on the pit portion may be removed. For example, when the disk surface is polished to a thin layer, the magnetic film in the pit portions, which is coated in a raised manner, is removed. FIG. 15 shows another example of a method for producing a magnetic recording medium in which the magnetic film (magnetic recording film) 5 of each preform pit 2o is removed. In FIG. 15(a), after a magnetic thin film 5 is uniformly sputtered on an aluminum or glass disk substrate 1, a positive resist 21 is applied, and this magnetic film 5 and a photoresist 2 are coated.
The above-described mask 130 is applied to the disk substrate 1 on which the mask 130 is formed.
exposed in close contact. In FIG. 15(b), after exposing the positive resist 21, the mask 130 is removed and the resist is developed. The resist in the pit portions 20 is dissolved by the development, but the other resist remains. In FIG. 15(c), for example, the magnetic thin film 5 in the pit portions 20 where the resist 21 does not exist is removed by etching using an ion milling method. In FIG. 5(d), for example, the resist 21 on the unexposed portion of the disk is removed using an organic solvent. This manufacturing method also makes it possible to create a magnetic recording medium in which the magnetic film 5 is not present only in the preform pits 20. FIG. 16 shows an example of a method for producing a magnetic medium in which each preform pit 2o is non-ferromagnetic. In FIG. 16, the processes in FIGS. 16(a), (b), and (d) are the same as those in FIG. 15(a), (b), and (d). In FIG. 16(c), for example, hydrogen, argon,
By implanting nitrogen, boron, neon, dysprosium, etc. 23 to replace the magnetic film 5 in the preform pit portion with ferromagnetic material, the preform pit portion 20
It is possible to create a magnetic recording medium that is not only ferromagnetic. If only the preform pits are made non-ferromagnetic in this way, since the recording film other than the pits is ferromagnetic, magnetic poles are formed on both walls of each preform pit 20, and as a result, the edges of the pits are Since a leakage magnetic field is generated, it can be detected magnetically by a magnetic head in the same way as described above. Note that FIG. 18 shows an enlarged view of the preform pit 20 formed by this manufacturing method. FIG. 17 shows an example of a method for producing a magnetic recording medium in which each preform pit 20 does not have a base film. In FIG. 17(a), after sputtering a Cr thin film 32 on an aluminum or glass disk substrate 1, a positive resist 21 is applied.
was applied to the disk substrate 1 on which the Cr underlayer 32 and photoresist 21 were formed. The mask 130 described above is exposed in close contact with the mask 130 . Figure 17 (b
), when the positive resist 21 is exposed, the mask 130 is removed, and the resist 21 is developed, the resist 21 in the pit portions 20 is dissolved by the development, but the rest of the resist 21 remains. In FIG. 17(c), the Cr thin layer 32 in the pit portion 20 where the resist 21 does not exist is removed by etching using, for example, a single-reactive ion etching method. In FIG. 17(d), for example, the resist 21 in the unexposed area on the disk is removed using an organic solvent. In FIG. 17(e), a ferromagnetic film 5 such as CoNiZr and a protective film 34 such as C are uniformly formed on the pattern of the Cr thin film 32 by sputtering. By this manufacturing method, it is possible to create a magnetic recording medium in which the Cr underlayer 32 is not provided only in the preform pit portion 20. Figure 19 shows preform pit 2 created by this method.
The 0 part is shown enlarged. FIG. 19(a) shows the magnetic head 10 scanning the preform pit 20, and FIG. 19(b) shows the magnetic film structure near the preform pit 20. The structure of the magnetic film other than the preform pit portion 20 is such that a base film of, for example, 300 to 500 nm is formed on an aluminum (AQ) or glass substrate 1.
A Cr film 32 with a thickness of m is formed by sputtering, and a ferromagnetic film 5 of CoNiZr or the like is formed on it with a thickness of 50 nm to 70 nm.
nm thick, and a protective film 34 made of C or the like is formed thereon by sputtering. In each preform pit portion 20, the Cr base film 32 is partially removed, and only the ferromagnetic film (recording magnetic film) 5 and the protective film 34 are formed. After the film is formed, the entire surface of the magnetic recording medium is initially magnetized uniformly by a magnet while being rotated. The magnetization direction 6 coincides with the disk circumferential direction, that is, the data recording direction. The Cr underlayer 32 has the effect of increasing the saturation magnetization Ms of the ferromagnetic film 5. Since there is no Cr underlayer 32 in each preform pit portion 20, the saturation magnetization at that location is small. If the recording magnetic film 5 is magnetized in one direction 6 by initial magnetization, there will be no leakage magnetic field at a location away from the preform pit 20. However, each preform pit 20 such as servo pit 3°3', 4.4', etc.
Since the saturation magnetization in that part is smaller than in other parts, positive and negative magnetic poles are formed on both walls 7 and 8 of each preform pit 20, and as a result, a magnetic field leaks from the edge of the preform pit. 9 is generated, so that it can be magnetically reproduced by the magnetic head 10 in the same way as described above. As described above in detail using FIGS. 14 to 19,
According to the manufacturing method of the present invention, it is possible to easily manufacture a magnetic recording medium provided with preform pits that are magnetically detectable and have locally different magnetic properties from those of the recording magnetic film. Moreover, since the mask 130 having a pattern of preform pits to be provided in advance on a magnetic recording medium can be used many times, a large number of magnetic recording media having the same pattern can be produced with high precision. In addition, the manufacturing method shown in FIGS. 14 to 17 also allows forming any pattern other than preform pits on the mask 130. For example, if a straight groove is made, the magnetic recording medium will not have a magnetic field. It is possible to preform straight grooves without membranes. Furthermore, it is of course possible to preform synchronization pits, address pits, or access pits in addition to tracking pits as servo pits. In addition, in the manufacturing method shown in FIGS. 14 to 16,
Although the protective film 34 was not explained. In the method for creating Figures 14 to 16, Figure 17 (
Similarly to e), it is preferable to form a protective film 34 made of C or the like on the recording magnetic film 5. In the above description, it is assumed that the data area between the servo areas is a magnetic recording medium that can be freely recorded and erased by the magnetic head 10. Here, a disk with this function will be named a disk with RAM function. However, as a further expanded use of discs, the 20th
As shown in the figure, an area 40 with a RAM function and an RO
M, that is, a disk configuration including a read-only area 39 is conceivable. With this configuration,
This has the advantage that read-only information and rewritable information can be accessed simultaneously in a short period of time. That is, the magnetic disk 1 has a magnetic film on which information can be magnetically recorded and reproduced, and has a second area (RAM area) 40 where the user can magnetically record and reproduce information, and a second area (RAM area) 40 where information can be magnetically reproduced. It has a preformed first area (ROM area) 39. In FIG. 20, the RAM area 40 is on the outer peripheral side. A ROM area 39 is provided on the inner circumferential side. In Fig. 2↓, the RAM area 40 is provided on the outer circumferential side, the ROM area 39 is provided on the inner circumferential side, and the ROM area 39 is provided as a RAM area.
They are angularly divided and mixed within the area 40. The RAM area 40 and the ROM area 39 are provided with concentric or spiral tracks, along which data is recorded and/or reproduced. FIG. 22 shows data recording tracks in the RAM area 40. In FIG. 22, data track 2,
2' is composed of a combination of a large number of servo areas 15 provided periodically along the track and RAM data 16 recorded in user information recording areas (data areas) between these servo areas 15. As described above, on each servo area 5, preform pits are formed, for example, by locally etching away the magnetic film and having magnetic properties different from those of the recording magnetic film. The magnetic field generated at the edge of the pit is transmitted to the magnetic head 1.
0 magnetically detects the sample and obtains a tracking signal.
While controlling the servo position of the magnetic head l○ based on the tracking signal, desired RAM data (for example, code data) 16 is recorded in the user information recording area (data area) between the servo areas 15 along the center line of tracks 2 and 2'. Record or play along. The magnetic film is a magnetic thin film for in-plane recording, and the RAM data 16 is magnetically recorded and reproduced in-plane by a tracking-controlled magnetic head 10. As explained in FIGS. 2, 3, and 9, the preform pits in the servo area 15 are a pair of tracking holes distributed left and right with respect to the center line of the tracks 2 and 2'. Servo pit 3, 4; 53°54
Alternatively, as explained in FIG. 10 and FIG. 11, different frequency and/or
Alternatively, a tracking mark consisting of pit rows 63, 64; 72, 73 having different phases is used. Further, address pits and kukotsuku pits 35 and 35' are preformed as necessary. An example thereof is shown in FIG. FIG. 23 shows an example of recording tracks in the RAM area 40. Each servo area 15 is preformed with a pair of servo pits 3 and 4 meandering relative to the track center as tracking servo marks. In the figure, pits indicated by 35 are preform pits for clocks and access marks, and are preformed on the base ml with the same magnetic film structure as the servo pits 3 and 4. Numeral 36 is a groove formed between tracks, and is used to reduce crosstalk during data reading between tracks. This groove 36 is also preformed with the same structure as the servo pits 3 and 4. 16 is the magnetic head 1
This shows data magnetically recorded in the data area by the vertical axis. FIG. 24 shows tracks dedicated to data reproduction in the ROM area 39. In FIG. 24, the data tracks 2, 2' consist of a number of servo areas 15 periodically provided along the tracks, and read-only ROM data (for example, code data) 17 provided between these servo areas 15 in any combination. It consists of Each servo area 15 and the ROM data 17 are both formed of preformed bits whose magnetic properties are different from those of the recording magnetic film, for example, by locally etching away the magnetic film, as described above. The magnetic head 10 magnetically samples and detects the magnetic field generated at the edges of the preform bits in the servo area 15 to obtain a tracking signal, and while controlling the servo position of the magnetic head based on the tracking signal, the servo area 15 The ROM data 17 between the tracks 2 and 2' is reproduced along the center line of the tracks 2 and 2'. ROM data 17 is only reproduced by the magnetic head and not recorded by the magnetic head.N. An example of recording tracks in the ROM area 39 is shown in FIG. Regarding the preform bits 3 and 4° 35 in the servo area 15 and the groove 36 between tracks in the data area, the 23rd
It is similar to that shown in the figure. Pit 17 in the data area
are preformed in the ROM 39 area in the same manner as the preform bits 3 and 4° 35 in the servo area. In this way, in the ROM area 39, both the pits in the servo area and the ROM data 17 in the data area are formed, for example, by locally etching away the recording film, as described above. The magnetic field generated at the edge of the preform bit in these servo areas is magnetically sampled and detected by a magnetic head to obtain a tracking signal, and the data area between the servo areas is controlled while controlling the servo position of the magnetic head based on the tracking signal. The ROM data 17 within is reproduced along the center line of the track. According to this embodiment, not only can ROM information be copied and recorded on a magnetic recording medium at low cost as a replica, but also ROM information and RAM information are mixed, so when used in a device such as a personal computer, software programs etc. can be written in advance. R
Since it can be formed on the magnetic recording medium as OM information, the effort of copying the software to the magnetic recording medium using a floppy disk can be saved. In addition, the first area (ROM area) and the second area (R
By providing a large number of servo areas periodically in advance in the AM area (AM area), the magnetic flux distribution generated in the preform bit in the servo area is magnetically detected by a magnetic head to control the servo position while the second area (AM area) is controlled. Recording and reproducing information in the first area (RAM area) or the first area (ROM area)
information can be read out. Effects of the Invention 1 According to the present invention, information can be recorded and reproduced while controlling the servo position by magnetically detecting the magnetic field generated in the preformed servo mark with a magnetic head, and high-density recording can be achieved. Ru. In addition, preform bits can be duplicated and recorded, and identical bits can be easily produced with high precision, so it is possible to produce large quantities of preformatted magnetic recording media at low cost. Further, according to the present invention, not only can servo information be inexpensively copied and recorded on a magnetic recording medium, but also ROM information and RAM information can be copied and recorded on a magnetic recording medium.
Information can be mixed. When used in a device such as a personal computer, software programs and the like can be formed in advance as ROM information on a magnetic B medium, thereby saving the effort of copying the software to a magnetic recording medium using a floppy disk.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an embodiment of the magnetic recording medium (magnetic disk medium) of the present invention, and FIGS. 2(a) to (c) each show a preform on the recording surface of the magnetic recording medium of FIG. Figures 3(a) to 3(d) show examples of recorded tracks.
4(a) is a diagram showing other examples of recording tracks preformed on the recording surface of the magnetic recording medium in FIG. 1, together with the recording area of the magnetic head, and FIG. 4(a) is similar to FIGS. 2 and 3. Showed 'V! FIG.
b) to (d) are the magnetism near the preform pit (i: approximate cross-sectional view showing the film structure; Figure 5 shows the magnetic head obtained when the magnetic head runs through the preform pit in a direction perpendicular to the data recording direction) 6 and 7 (a) to (c) are diagrams for explaining the tracking signal detection operation according to the present invention, and FIG. 6 shows a meandering tracking servo pit. 7(a) to (C) are diagrams showing the relationship between the magnetic head and the magnetic head that scans them.
Figures showing examples of detected waveforms obtained when the magnetic head scans along the scanning values IA, B, and C in Figure 6. Figure 8 shows the data area while tracking is controlled using the tracking signal detected in the servo area. A diagram for explaining an embodiment of the recording and reproducing method of the present invention for recording and reproducing data on the
Figures 9 and 10. FIG. 11 is a diagram showing another example of tracking servo pits preformed in each servo area. FIG. 12 is a diagram for explaining a method for detecting tracking signals from the tracking servo pits shown in FIGS. 10 and 11, and FIG. 13(a) is a mask recording apparatus used in the recording medium production method of the present invention. Figure 13 showing an example of
Figure (b) is a diagram for explaining a method for forming --shaped rectangular preform pits, and Figures 14 to 17 each illustrate an embodiment of the method for producing a magnetic recording medium of the present invention. FIGS. 14(a) to 14(d) are diagrams showing an example of a method for creating a magnetic medium in which the magnetic film of the preform bit is removed, and FIGS. 15(a) to (d) are diagrams showing the method Figures 16(a) to 16(d) are diagrams showing other examples of the manufacturing method, and Figures 17(a) to 17(e) are diagrams showing an example of the manufacturing method of a magnetic medium in which preform pits are non-ferromagnetic. ) is a diagram showing an example of a method for creating a magnetic medium with the underlying film of the preform pit removed, FIG. 18 is a diagram showing the magnetic film structure near the preform pit by the manufacturing method shown in FIG. 16, and FIG.
), (b) are diagrams showing a method of reproducing a preform bit according to the production method shown in FIG. 18 and its magnetic film structure, and FIG.
21 shows an embodiment of the magnetic recording medium of the present invention, a diagram showing a magnetic disk medium in which a ROM area and a RAM area are mixed, and FIGS. 22 and 23 each show an example of a recording track in the RAM area. Figures 24 and 25 showing
Each figure shows an example of a read-only track in the ROM area. Kuzu / Figure 3 (A) (B) (C7) Figure 7 Figure 7 Figure 72 City / 3 Nagimi / Figure 1? Diagram flute 2/diagram

Claims (1)

[Claims] 1. A magnetic recording medium having a magnetic film that stores information in a form that can be magnetically recorded and reproduced, in which servo areas for detecting tracking signals are provided periodically along the track. , a magnetic recording medium is used in which each servo area has preformed servo pits with magnetic properties different from those of the magnetic film, and when a magnetic head scans each of the servo areas, the preformed servo pits are The tracking signal is obtained by detecting the generated magnetic field, and the magnetic head transmits information between the servo areas while controlling the tracking so that the magnetic head follows the center of the track based on the obtained tracking signal. A method for magnetically recording and reproducing information, characterized by recording or reproducing information. 2. The magnetic recording and reproducing method according to claim 1, wherein the tracking signal is detected by detecting a magnetic field generated at the edge of the preformed servo pit. 3. As the magnetic recording medium, use is made of a magnetic recording medium consisting of at least a pair of wobble servo pits in which the preformed servo pits of each of the servo areas are provided in a meandering manner with respect to the center of the track; 2. The magnetic recording and reproducing method according to claim 1, wherein the tracking signal is detected from a difference in output obtained by detecting a magnetic field generated in each of the wobble servo pits with the magnetic head. 4. The magnetic recording medium is a magnetic recording medium in which the preformed servo pits in each servo area are composed of a set of pit rows with different frequencies, and the set of pit rows is scanned by the magnetic head. 2. The magnetic recording and reproducing method according to claim 1, wherein the components of the different frequencies are detected from the output obtained by the magnetic recording and the tracking signal is detected from the difference between the detected signals. 5. The magnetic recording medium includes a first area having preformed data pits having magnetic properties different from those of the magnetic film between the servo areas, and data can be recorded by the magnetic head between the servo areas. 1. A magnetic recording medium having a second area having a recording area is used, and the magnetic field generated in the preformed data pit is detected by the magnetic head to reproduce the data pit. 5. The magnetic recording and reproducing method according to any one of 4 to 4. 6. The magnetic head according to claim 1, wherein the length of the preformed servo pit in a direction perpendicular to the track is approximately the same as that of the recording portion of the magnetic head. Recording and playback method. 7. The magnetic recording/reproducing method according to claim 1, wherein the magnetic recording medium is a magnetic recording medium in which the preformed servo pits are formed by removing the magnetic film. Method. 8. As the magnetic recording medium, use is made of a magnetic recording medium in which the preformed servo pits are formed by making the magnetic film locally non-ferromagnetic. magnetic recording and reproducing method. 9. The magnetic recording medium used is a magnetic recording medium in which the preformed servo pits are formed by removing a base film under the magnetic film. magnetic recording and reproducing method. 10. A magnetic recording medium having a ferromagnetic film on which magnetically readable information is recorded, in which servo areas for detecting tracking signals are provided periodically along the track, and each servo area has a A magnetic recording medium having preformed servo pits having magnetic properties different from those of the magnetic film. 11. The magnetic recording medium according to claim 10, wherein the preformed servo pits in each of the servo areas are comprised of at least a pair of wobbled servo pits provided in a meandering manner with respect to the center of the track. 12. The magnetic recording medium according to claim 10 or 11, wherein the preformed servo pits in each of the servo areas are not formed with the magnetic film. 13. The magnetic recording medium according to claim 10 or 11, wherein the preformed servo pits in each of the servo areas are formed by making the magnetic film locally non-ferromagnetic. 14. The magnetic recording medium according to claim 10 or 11, wherein the preformed servo pits in each of the servo areas are formed with unevenness, and the magnetic film is not formed on those portions. 15. The magnetic recording medium according to claim 10 or 11, wherein the preformed servo pits in each of the servo areas are formed by removing a base film below the magnetic film. 16. The magnetic recording medium according to claim 10, wherein the preformed servo pits in each of the servo areas are comprised of a set of pit rows having different frequencies. 17. A first area having preformed data pits having different magnetic properties from the magnetic film between the servo areas, and a second area having a recording area where data can be recorded by the magnetic head between the servo areas. 17. The magnetic recording medium according to claim 10, wherein the magnetic recording medium has a region. 18. The magnetic recording medium according to claim 17, wherein the first area and the second area are angularly divided and coexist. 19. A magnetic recording medium having a magnetic film and capable of magnetically recording and reproducing information, comprising a first area in which magnetically reproducible information is provided in advance, and a region in which a user magnetically records information. A magnetic recording medium characterized in that it has a second reproducible area. 20. The magnetic recording medium according to claim 19, wherein the first area and the second area are angularly divided and coexist. 21. The magnetic recording medium according to claim 19 or 20, wherein the magnetically reproducible information is recorded in the first area by partially removing the magnetic film. 22. In the first area, a large number of magnetically reproducible servo marks recorded by partially removing the magnetic film are provided periodically along the track, and between these servo marks, the magnetically reproducible servo marks are recorded by partially removing the magnetic film. 22. The magnetic recording medium according to claim 19, wherein reproducible information is provided on the magnetic recording medium. 23. In the second area, a large number of magnetically reproducible servo marks recorded by partially removing the magnetic film are provided periodically along the track, and user information is recorded between these servo marks. 23. The magnetic recording medium according to claim 19, wherein the magnetic recording medium is a region. 24. The method for manufacturing a magnetic recording medium according to any one of claims 10 to 23, wherein a mask having a pattern of servo pits provided in advance in the servo area is prepared, and a resist provided on the magnetic film is Preforming the servo pit by exposing through the mask, removing the resist corresponding to the pattern, and using the resist as a mask to vary the magnetic properties of the portion of the magnetic film corresponding to the pattern. A method of manufacturing a magnetic recording medium characterized by: 25. The manufacturing method according to claim 24, wherein the servo pit is preformed by removing a portion of the magnetic film corresponding to the pattern. 26. The manufacturing method according to claim 24, wherein the servo pit is preformed by making a portion of the magnetic film corresponding to the pattern non-magnetic. 27. The manufacturing method according to claim 24, wherein the servo pit is preformed by partially removing a base film under the magnetic film corresponding to the pattern. 28. A magnetic head from the magnetic recording medium according to any one of claims 10 to 23 detects a tracking signal by detecting a magnetic field generated in the servo pit, and controls the recording position of the magnetic head using the tracking signal. A magnetic recording device characterized by magnetically recording information while 29. The magnetic recording device according to claim 28, wherein the length of the servo pit in the direction perpendicular to the data recording direction is approximately the same as the width of the recording portion of the magnetic head.