JPS60109018A - Vertical magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To perform high-density recording through a tracking servo by providing vertical magnetic tracks and tracking signal tracks on the same disk, and reproducing and detecting both tracks with the same stylus. CONSTITUTION:Vertical magnetic tracks for an information signal and tracking signals tracks consisting of ungrooved electrostatic capacity type pit strings are arranged spirally or concentrically and alternately on the same disk medium 1. A stylus 7 which traces on the surface of the rotating medium 1 consists of a vertical magnetic head having a magnetic material film 2 used in common as a pickup electrode which detects capacity variation due to pit strings for the recording and reproduction of the information signal. Then, a circuit 10 detects a tracking signal from the capacity variation between the medium 1 and a magnetic material film 2, a circuit 11 discriminates the track deviation of the stylus 7 from the detected tracking signal, and tracking driving mechanisms 9 and 12 receives the tracking deviation signal to displace the stylus 7 in the track breadthwise direction.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to an apparatus for recording and reproducing information signals on a perpendicular magnetic recording disk medium, and particularly to a tracking control technique for achieving high-density recording.

BACKGROUND ART The perpendicular magnetic recording system has attracted attention as a high-density magnetic recording system that overcomes the recording density limitations of the conventional horizontal recording system, and various research and development efforts are underway.

Recently, there have been few announcements of practical devices of this kind that use disk media, such as floppy disk devices based on the perpendicular magnetic recording method. However, the devices announced so far in gQ are perpendicular magnetic recording systems, as described below. It could not be said that the feature of high-density recording was fully utilized.

In the already known perpendicular magnetic recording type floppy disk device, the recording density is 50 KBP in linear density.
I (1 bit difference, j) 0.5. c+m), track density is 144TjI () rack pitch is 176μ
m) are obtained. Here, the linear density is 50KB
The value of PI can be evaluated as a sufficiently high value that takes advantage of the characteristics of this recording method. However, the track density is 144TP
The value of I is very low compared to other types of records/stem. For example, optical recording and reproducing systems and magneto-optical recording systems have achieved trunk pitches of about 1.35 to 2 .mu.m, and compared to these, the track density of the previous example is about 17,130. As a result, the total recording density, that is, the areal density, can only be achieved as low as several tenths of that of optical recording and reproducing systems.

The cause of this is the tendency of the tracking control of the perpendicular magnetic head with respect to the perpendicular magnetic recording disk medium. As is well known, in optical recording and reproducing systems, capacitive recording and reproducing systems, and the like, tracking servo is employed for rounding to increase track density. This is a servo fai control that detects the trunk error of the pickup from the playback signal and feeds it back to the pick depth position to precisely trace the track on the medium with the pickup.

On the other hand, for perpendicular magnetic recording devices, no practical tracking servo system based on reproduction signals has been developed. Therefore, control for positioning the perpendicular magnetic head by displacing it in the track width direction is performed in an open loop. Therefore, the tracking accuracy greatly depends on the positioning accuracy of the head drive mechanism (head slider), and this depends on the positioning accuracy of the truss 1. This is the biggest factor limiting density.

Even if a high-precision feeding/positioning mechanism, such as a feeding mechanism using a stamping motor or a wire belt feeding mechanism, is employed in the head drive system, the track density described above is almost at its limit.

DISCLOSURE OF THE INVENTION An object of the present invention is to dramatically increase the track density in a perpendicular magnetic recording apparatus using a disk medium by using easy-to-implement tracking servo.

In order to achieve the above object, in the present invention, perpendicular magnetic trunks for information signals and tracking signal trunks consisting of grooveless capacitive bit strings are arranged alternately on the same disk medium in a spiral or concentric manner. It was formed into a shape. In addition, a magnetic stylus that traces the surface of a rotating disk medium can be used both for recording and reproducing information signals on the perpendicular magnetic track and as a pickup electrode for detecting capacitance changes due to the bit string of the tracking signal track. It was constructed with a perpendicular magnetic head on which a body film was completely formed.

Furthermore, a circuit for detecting the tracking signal from a capacitance change between the disk medium and the magnetic film, a circuit for discriminating a tracking error of the stylus from the detected trunking signal, and a circuit for receiving the obtained tracking error signal. A tracking drive mechanism for displacing the stylus in the track width direction is provided. This realizes a tracking servo that allows the magnetic film, which is the main pole of the perpendicular magnetic head, to follow the perpendicular magnetic recording trunk with high precision based on the tracking signal detected by itself.

According to the present invention, fine tracking by servo control is possible, and the track density can be increased several ten times as compared to known devices without tracking servo. Furthermore, it is not difficult to manufacture a disk medium in which a perpendicular magnetic recording track and a capacitance type tracking signal track are arranged side by side. The invention as a whole is very easy to implement.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a schematic configuration of an apparatus according to the present invention.

A disk medium 1 (hereinafter referred to as disk) is rotated at a constant speed in the direction of the arrow by a mechanism not shown. disc 1
As will be described later, a magnetic layer for perpendicular magnetic recording is formed on the upper surface side, and the main magnetic pole 2 and auxiliary magnetic pole 3, which constitute the auxiliary magnetic pole excitation type perpendicular magnetic head, are located on the upper and lower surfaces of the disk 1, respectively. placed opposite. The winding 4- of the auxiliary magnetic pole 3 is connected to an information signal recording circuit 5 and a reproducing circuit 6. The principle of perpendicular magnetic recording and reproducing using an auxiliary magnetic pole excitation type head is well known, so it will not be explained here.

The main magnetic pole 2 is made of permalloy (Fe-N) in front of the stylus 7 made of a hard material such as diamond or sapphire.
i alloy) etc. by vapor deposition (thickness 02~0,
In other words, it consists of an extremely thin main pole film (about 3 μIn). The stylus 7 is fixed to the tip of a cantilever 8 extending from a stylus actuator 9. The actuator 9 is an electro-mechanical converter using a coil and a magnet, and receives a coil drive signal from a driver 12 to move the stylus 7 at the tip of the cantilever 8 in the radial direction (track direction) of the disk 1, as described later. (width direction). Further, the actuator 9 and the auxiliary magnetic pole 3 are mounted on a slider (not shown), and both are simultaneously moved largely in the radial direction of the disk 1.

FIG. 3 shows the shape of the stylus 7, and FIG. 4 shows the disk 1 and the stylus 7 in detail in a partially enlarged manner.

As shown in both figures, the stylus 7 is shaped like a pentagonal pyramid, and the sliding surface in contact with the disk 1 at its tip is a pentagonal plane. The arrow in FIG. 4 indicates the rotational direction (track direction) of the disk 1, and the main magnetic pole film 2 (magnetic film) is formed on the front surface of the stylus 7 perpendicular to this direction.

This magnetic film 2 is perpendicular to the surface of the disk 1. As shown in FIGS. 3(A)I and (B), the magnetic film 2 is
Together with the stylus body 7, it is formed in a tapered shape in the direction of the tip, that is, in the direction of the sliding surface in contact with the disk 1. As a result, the contact area with the trunk 13 for information signals is minimized, and the track density is increased.

On the surface of the disk 1, there is a perpendicular magnetic recording trunk 13 for information signals and a grooveless capacitive pit row 14, 1.
Tracking signal tracks 15 consisting of 4, . . . are arranged in a spiral shape. That is, tracks 13 and tracks 15 are alternately arranged in the radial direction of the disk l.

The base 19 of the disk 1 is made of conductive polyimide, polycarbonate, polyester, etc. mixed with fine carbon powder and is injection molded to a thickness of approximately 100 μm. It,... can be formed at the same time. A magnetic layer 16 (Co
-Cr layer or a two-layer film of Co-Cr layer and Ni-Fe'), an insulating layer 17 such as polystyrene, and a stylus 7.
A lubricating layer 18 is laminated in this order to reduce the sliding resistance.

As a specific example of dimensions, the width of the perpendicular magnetic recording track 13 is about 4 μm, the width of the tracking signal trunk 15 is about 1/Jm, and the track pitch including both is about 5 μm. Further, the width of the magnetic film 2 at the tip of the stylus 7 is about 4 μm, which is almost the same as the track 13, but in reality, the processing limit on the stylus 7 side limits the width of the track 13.

Next, the tracking signal will be explained. The frequency of the trunking signal (the pitch of the pits 14) is alternately switched between fl and f2 every rotation of the disk 1. Therefore, the frequencies of the tracking signals are always different on both sides of the perpendicular magnetic recording track 13. If the rotational speed of the disk 1 is expressed as a frequency f3, then the frequency of the tracking signal is likely to be switched at the frequency f3. This switching frequency signal of 103 is also used as an intex signal for identifying trunks.

Next, the tracking servo will be explained. The magnetic film 2 made of permalloy or the like has electrical conductivity. In this invention, the conductivity of the magnetic film 2 is utilized to connect the pit arrays 14, 14, . It functions as a pink-up electrode that detects changes in capacitance due to...

The magnetic film 2 is connected to the capacitance change detection circuit 1 by a fly lead.
0, and the above-mentioned tracking signal is detected by this circuit from the change in capacitance between the magnetic film 2 and the disk 1. The detected tracking signal is input to a tracking error detection circuit 11, and the tracking error is discriminated by comparing the levels of the frequency components of the tracking signal. The track difference signal is applied to the above-mentioned stylus actuator 9 via the driver 12, thereby displacing the stylus 7 in the track width direction in a direction to cancel the track error.

FIG. 2 shows a specific example of the configuration of the above-mentioned amount change detection circuit 10 and tracking error detection circuit 11.

The mold part of the capacitance change detection circuit IO is a coaxial resonant circuit 20 in which the magnetic film 2 (big amplifier electrode) is a part of the resonant element. In addition, the resonant frequency f. A signal with a slightly different frequency is applied from a UHF oscillator 21, the output of which is taken out via a detector 22 and input to a preamplifier 23. Therefore, from the preamplifier 23', the frequency f0
A signal is obtained in which the amplitude of the signal is modulated by the tracking signal on the disk l.

The output signal of the preamplifier 23 has a frequency fljf2°f3
A bandpass filter 24゜25.26 that separates and extracts
is input. Frequency f extracted by bandpass filter 26
The signal No. 3 (one rotation of the disk 1 is one cycle) is detected by the detection circuit 27 and waveform-shaped by the switching signal generation circuit 28 to become a switching signal for controlling the switching circuit 29. In response to this signal, the switching circuit 29 is switched every rotation of the disk 1, and the outputs of the bandpass filters 24 and 25 are alternately input to the detection circuits 30 and 31. Detection circuits 30 and 31
The output is input to a differential amplifier 32 for level comparison, and the output is applied to the driver 12 via a phase compensation circuit 33.

With this circuit configuration, in the differential amplifier 32, the detection level of the tracking signal located on the left side of the track 13 being traced by the stylus 7 can be compared with the detection level of the tracking signal located on the right side. . If the stylus 7 accurately traces the track 13, the output of the differential amplifier 32 is zero. When the stylus 7 shifts to one side, the detection level of the trunking signal on the shifted side increases, and the output of the differential amplifier 32 changes to positive or negative. This tracking error signal becomes a drive signal for the stylus actuator 9 to correct the above-mentioned deviation of the stylus 7. In this way, the tracking servo is activated, the main magnetic pole 2 accurately traces the perpendicular magnetic recording track 13, and information signals are recorded and reproduced.

In the above explanation, the track pattern on the disk is spiral-shaped, but the present invention can be practiced in the same manner as described above even with a concentric trunk pattern. However, the present invention can also be applied to so-called double-sided discs in which recording media are formed on both sides of the disc.

In the above embodiment, an auxiliary pole excitation type head composed of a main pole film 2 and an auxiliary pole 3 was used as the perpendicular magnetic head constituting the stylus, but the present invention is not limited to this. The present invention is not limited to this, and various other head structures may be employed.

FIG. 5 shows one example, and the same parts as in the above embodiment are denoted by the same reference numerals, and the explanation thereof will be omitted.

In FIG. 5, a perpendicular magnetic head 30 constituting a stylus similar to that described above is attached to the tip of the cantilever 8. The magnetic head 30 is a so-called main pole excitation type head, and includes a magnetic yoke 31 made of ferrite, etc., which is attached to the tip of a cantilever 8 and is formed in a substantially U-shape opening downward. A thin magnetic film 32 made of so-called permalloy (Fe-Ne alloy) is deposited on the front end surface of the magnetic yoke 31, and the front surface of the yoke 31 is sandwiched between the magnetic film 32 in a sandwich-like manner. It consists of a hard plate material 33 made of glass or the like adhered to the magnetic yoke 31, and a slider 35 made of a non-magnetic material that slides along the track surface of the disk 1 attached to the lower open end of the magnetic yoke 31. .

At the front end of the magnetic yoke 31, a winding (coil) 36 similar to that described above is wound around the bonded portion of the yoke 31, magnetic film 32, and hard plate 33. I'm being kicked. The coil 36 is connected to the information signal recording circuit 5 and reproduction circuit 6 in the same way as described above (the first
(see figure).

A main magnetic pole is formed by the magnetic film 32 .

This main magnetic pole film 2 also serves as a pickup electrode for capacitance detection based on the bit string 14.14 of the tracking signal track, and is connected via a fly lead 37 to the slope detection circuit, that is, the coaxial resonant circuit 20 of the capacitance change detection circuit 10. (See Figure 2).

The slider 35 is formed so that the rear 1+11 along the disk traveling direction is inclined upward and rearward at a constant angle with respect to the disk surface. The lower end portion of the hard plate phase 33 which is still in sliding contact with the disk 1 has a substantially keel shape and is narrowly drawn to reduce the area in contact with the tracks of the disk.

FIG. 6 shows still another example of the above-mentioned perpendicular magnetic head, and this perpendicular magnetic head 40 is composed of a main pole excitation type head with an auxiliary pole.

In Figure 6, a magnetic yoke 41 whose lower end is constricted into a recessed keel shape is attached to the tip of the cantilever 8, and a magnetic film 4 having the same structure as described above is attached to the front surface of the magnetic yoke 41.
2 is completely adhered.

A hard plate material 43 made of glass or the like is completely attached to the front surface of the magnetic yoke 41 so as to sandwich the magnetic film 42 therebetween. A winding 44 is wound around the bonded portion of the head body constructed in this way. This winding 44 is connected to the recording circuit 5 and the reproducing circuit 6. Further, the magnetic film 42 is connected to the coaxial resonant circuit 20 of the capacitance change detection circuit 10 via a fly lead 45. Further, an auxiliary magnetic pole 46 is disposed on one side of the disk 1 so as to face the main magnetic pole film 42 . The auxiliary magnetic pole 46 and the stylus actuator 9 are sent in the same direction relative to the disk 1.

Portion (surface) of the hard plate material 43 that comes into sliding contact with the disk 1
is formed with a taper at a certain angle rearward and upward in the disk traveling direction, and is tapered to minimize the contact area with the trunk surface of the disk.

Next, FIG. 7 shows still another embodiment of the above-mentioned perpendicular magnetic head, in which the magnetic head 50 is constructed of a so-called ring-shaped head.

As shown in FIG. 7, a substantially U-shaped first magnetic yoke 51 that is open to the front is attached to the tip of the cantilever 8. As shown in FIG. A second magnetic yoke 52 is attached to the front open end side of the first magnetic yoke 51 so as to have a certain narrow magnetic gap 53 therebetween. A thin magnetic film 54 made of permalloy or the like similar to that described above is adhered to the front surface of the second magnetic yoke 52 . Further, a winding (coil) 55 is wound around the outer circumference of the vertical portion of the first magnetic yoke 51 . This winding 55 is connected to the recording circuit 5 and the reproducing circuit 6. In addition, the magnetic film 54
The above capacitance change detection circuit 10 is connected via the fly lead 56.
It is connected to the. Furthermore, the lower ends of the first and second magnetic yokes 51, 52 and the magnetic film 54 are tapered in a substantially keel shape so that the tips are narrow, and the portions that contact the trunk surface of the disk are narrow. It is designed to be as small as possible.

It goes without saying that even with the head structure shown in FIGS. 5 to 7 as described above, the same effects as those of the above embodiment can be achieved, and the details such as the tracking servo operation are substantially the same as those described above. Therefore, this is omitted.

By employing the head structure shown in FIGS. 5 to 7 as described above, the track width can be made narrower than ever before, and the trunk pitch can be made smaller and narrower.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a perpendicular magnetic recording and reproducing apparatus according to the present invention, FIG. 2 is a block diagram showing a specific example of the main circuit in FIG. 1, and FIG. 3 (4) (B-C) 4 is a partially enlarged sectional view of the disk stylus, and FIGS. 5 to 7 show other embodiments of the perpendicular magnetic head constituting the stylus used in the present invention. FIG. 3 is a partially enlarged perspective view. 1...Disk, 2.32,42,54...Magnetic film, 7...
- Stylus, 9110.1. Meta 1 Las Actuator, 10...
...Capacitance change detection circuit, 11... Track difference detection circuit, 13...
... Perpendicular magnetic recording track, 14... Pit, 15... Tracking signal track, 16...
... Magnetic layer, 17 ... Insulating layer, 18 ... Moist layer. Patent applicant: NEC Home Electronics Figure 1 (A) Figure 3 (B) (C)

Claims (5)

[Claims] (1) Perpendicular magnetic recording tracks for information signals and tracking signal trunks consisting of grooveless capacitive pit rows are formed alternately in a spiral or concentric manner on the same tape medium; A stylus is used to trace the surface of the medium with a rotating bag, or to record and reproduce information on the -11 vertical peak recording trunk, and to detect changes in capacitance due to the pinot column of the tracking signal trunk. It is composed of a perpendicular magnetic head on which a magnetic film is formed, which also serves as a pick-up electrode for the pickup. a tracking drive mechanism that receives the obtained tracking error signal and displaces the stylus in the trunk width direction; the main magnetic pole of the vertical magnetic head; Mi
A perpendicular magnetic recording/reproducing apparatus characterized in that the J magnetic film is made to correctly follow the perpendicular magnetic recording track. (2) The perpendicular magnetic head comprises a main magnetic pole for recording and reproducing information signals on the perpendicular magnetic recording track, and an auxiliary magnetic pole provided to sandwich the disk and face the main magnetic pole. The magnetic material film is formed on the main magnetic pole, and the magnetic film is tapered in the direction of the tip. A perpendicular magnetic recording/reproducing apparatus according to claim 1. (3) Tapered in the direction of the tip of the magnetic head, which also serves as a pickup electrode for recording and reproducing information on the 18th report and detecting capacitance changes due to the tracking bit string)
2. The perpendicular magnetic recording and reproducing apparatus according to claim 1, wherein the perpendicular magnetic recording and reproducing apparatus is constituted by a main pole excitation type head having a main pole made of the magnetic film which is narrowed in a shape. (4) The front self-stylus sandwiches a magnetic yoke formed in a substantially U-shape that opens downward, the magnetic film attached to the front surface of the magnetic yoke, and the magnetic film in a sandwich-like manner. a hard plate that is wrinkled on the front surface of the magnetic yoke so as to fit into the magnetic yoke, and whose lower end is narrowed into a substantially keel shape; The perpendicular magnetic recording and reproducing device according to claim 1 or 3, characterized in that the perpendicular magnetic recording and reproducing device is constituted by a winding wire wound so as to surround the bonded portion of the body membrane and the hard plate material. Device. (5) The perpendicular magnetic head constituting the stylus is a ring-shaped head, and the head is approximately U-shaped with an opening on the front side, and has a first ring-shaped head whose lower end is narrowed into an approximately keel shape.
and a front end opening 1+1 of the first magnetic yoke.
11 with a certain gap, and 1
a second magnetic yoke whose end is narrowed into the keel shape;
Perpendicular magnetic recording and reproducing according to claim 1, wherein the magnetic film also serves as a pickup electrode for detecting capacitance changes due to the tracking pit array attached to the second magnetic yoke. Device.