JPS6168723A - Tracking servo system for reading and writing head and magnetic recording medium for its system - Google Patents

Abstract

PURPOSE:To improve the track density of vertical recording by detecting servo information stored an in-surface magnetized area on a magnetic recording medium by a servo information reading head, and positioning the reading and writing head on the basis of the detection signal. CONSTITUTION:The magnetic recording medium 1 consists of an in-surface magnetized area 2 where the servo information is written by in-surface recording and a vertically magnetized area 3 which is formed in the area 2 by lamination and where data information is written by vertical recording. The medium 1 has annular tracks of width (t) concentrically at a pitch T and the servo information is written by in-surface recording. A servo head 4 has gap width equal to the track width (t), and when the head 4 shifts from a normal track position and is displaced by X, its detection signal is obtained and supplied to a window detector 12 through an amplifier 11 to obtain a displacement signal corresponding to the phase difference based upon a rotational position signal SN. Tracking servo is carried out on the basis of this displacement signal to improve the track density of vertical recording.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a tracking servo system for a read/write head that allows high track density to be obtained in perpendicular recording, and a magnetic recording medium applied to the system.

[Conventional technology]

Conventional head tracking servo methods include, for example, a servo surface servo method used for in-plane recording, and an embedded servo method in which servo information is added between data information. In the former, only data related to servo information is recorded on one side of a recording medium such as a magnetic disk, and data other than servo information is recorded (reproduced) on the other side, and the bed tracking servo is detected while detecting the servo information. This is what we do. In the latter case, tracking servo is performed by pre-recording servo information at regular intervals on the same surface of the recording medium, and data information is recorded (reproduced) in the gaps between the servo information. By performing such tracking servo, it is possible to completely synchronize the head positions during recording and reproduction, and recording and reproduction can be performed without any trouble.

[Problem that the invention seeks to solve]

However, according to the conventional head tracking servo method, when a servo surface servo method is applied, when a flexible disk is used, the disk deforms into a convex shape toward the head surface, so the medium surface comes into contact with the head on the other side. (There is a possibility that tracking information will not be obtained. Furthermore,
If the embedded servo method is applied, it can be applied to flexible disks, but since servo information is inserted between data information, the amount of data information will be reduced, and a configuration that separates servo information and data information will be required. is required, which has the disadvantage of increasing the burden on the hardware.

[Means and effects for solving the problems] The present invention has the following features:
This was done in view of the above, and in order to increase the track density in perpendicular recording, a perpendicular magnetized region is formed on the surface of the in-plane magnetized region to form a magnetic recording medium, and tracking recorded in advance in the in-plane magnetic region is used. The present invention provides a tracking servo system for a read/write head in which tracking servo is performed by detecting servo information, and a magnetic recording medium applied to the system.

〔Example〕

Hereinafter, the bed tracking servo system and magnetic recording medium according to the present invention will be explained in detail.

FIG. 1 shows an embodiment of the magnetic recording medium of the present invention, and the magnetic recording medium 1 includes an in-plane magnetized region 2 in which servo information is written in advance by in-plane recording, and a layer laminated on the in-plane magnetized region. The perpendicular magnetization region 3 is formed and data information is written by perpendicular recording.

As shown in FIG. 2, the heads for forming these two magnetized regions include a ring-shaped servo head 4 for reading servo information, and a single-pole type read/write head 5 for perpendicular recording. Use an integrated type.

After the head 4 previously records servo information on the magnetic recording medium l using the in-plane recording method, the head 5 records data information on the surface of the in-plane magnetization region using the perpendicular magnetization method. At this time, since the magnetization from the tip of the head by the head 5 is only a perpendicular component, the stereo information recorded in the in-plane magnetized area 2 is preserved without being erased.

FIG. 3 shows an embodiment of the tracking servo system of the present invention, which includes an amplifier 11 that amplifies the output signal of the servo head 4 that detects servo information, and the servo information and rotational position signal SN output from the amplifier 11. a window detector 12 that detects whether the phase of the displacement from the normal track position is shifted by 180 degrees based on the servo head 4; and an integral that integrates the output signal of the window detector 12 to determine the track position of the servo head 4. 13, a zero comparator 14 that detects whether the output signal of the integrator 13 is at zero level, and a linear motor 16 that drives the servo head according to the output signal level and polarity of the zero comparator 14. 4 in the track width direction, and a linear motor controller 15 that controls the linear motor 16 to be stopped when the zero comparator 14 detects the zero level of the output signal of the integrator 13.

In the above configuration, the tracking servo method will be explained based on the servo head position explanatory diagram of FIG. 4 and the servo head detection signal waveform diagram of FIG. 5.

As shown in FIG. 4, ring-shaped trunks each having a width t are sequentially formed concentrically with pinches T on the magnetic recording medium 1, and servo control is performed as shown by the arrows. 1 is recorded within the plane (note that the illustration of data information is simplified in FIG. 4). The servo head 4 has a gap width that is the same as the track width t, and is controlled to trace in a state where the two always overlap. Under such a situation, the output signal output from the servo head 4 is the same because the magnetization levels of block a and block b are opposite to each other.
As shown in FIG. 5(a), the detection signal is at zero level. However, as shown by the hatched frame in FIG. 4, when the head 4 deviates from the normal track position and a displacement of X occurs, a level detection signal is obtained. In other words, does the displacement
, a sinusoidal signal with a phase difference of 180 degrees depending on whether it goes outside (assumed to be a negative displacement) is shown in Figures 5 (b) and 5.
The output is as shown in Figure (C). This is servo head 4
On the other hand, since the blocks a and b are disposed unbalancedly, the magnetization of either one can be detected.

The detected servo information is amplified to a predetermined level by the amplifier 11 and then output to the window detector 12, where the window detector 12 obtains a displacement signal according to the phase difference based on the rotational position signal S8. This displacement signal is integrated by an integrator 13, and a linear motor controller 15 drives a linear motor 16 based on this integrated signal. If the displacement is toward the inside, move the servo head 4 to the outside,
On the other hand, if it is on the outside, it is moved in the opposite direction. By performing this operation, when the gap portion of the servo head 4 overlaps the track width, the output of the integrator 13 becomes zero. At the same time, the zero comparator 14 operates to control the linear motor controller 15 to stop the linear motor 16, and the movement of the servo head 4 is stopped.

Note that the magnetization wavelength of the in-plane magnetization region does not need to be a short wavelength, and the rotational position signal is usually set to twice the wavelength.

Furthermore, although an example has been shown in which the head is constructed by integrating a ring-shaped head and a main pole excitation type single magnetic pole head, it is also possible to combine a ring type head with an auxiliary excitation type single magnetic pole head.

〔Effect of the invention〕

As explained above, according to the tracking servo method of the read/write head of the present invention and the magnetic recording medium applied to the method, the in-plane magnetized area for recording servo information and the data information are arranged in the thickness direction of the recording medium. Recording (or playback)
The perpendicular magnetization region is formed in a two-layer state, and the servo information is detected to perform tracking servo.
Track density in perpendicular recording can be improved.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an embodiment of a magnetic recording medium according to the present invention, FIG. 2 is a perspective view showing an example of a head for recording and reproducing information on the recording medium of FIG. 1, and FIG. A block diagram showing the configuration of the head tracking servo system according to the present invention, FIG. 4 is an explanatory diagram when there is a positional deviation in the head, and FIG. 5 is a detection signal waveform diagram of the servo head according to the present invention. ...Magnetic recording medium 2...In-plane recording area 3...
- Vertical recording area 4... Servo head 5... Read/write head 11... Amplifier 12... Window detector 13... Integrator 14... Zero detector 15... Linear motor controller 16... Linear motor Figure 1 Figure 2

Claims (2)

[Claims] (1) In a magnetic recording medium comprising an in-plane magnetized area for storing servo information for positioning a read/write head and a perpendicular magnetized area for storing data information, the servo information in the in-plane magnetized area is used for servo control. A tracking servo system for a read/write head, characterized in that detection is performed by an information reading head, and positioning of the read/write head is performed based on a detection signal from the servo information reading head. (2) It is characterized by comprising an in-plane magnetized region that stores servo information for positioning the read/write head, and a perpendicular magnetized region that is laminated on the in-plane magnetized region and stores data information. Magnetic recording medium for tracking servo system for read/write heads.