JPH02310818A - Head device and head positioning controller for data recording and reprodcing device - Google Patents

Abstract

PURPOSE:To respectively read data and servo information at a high S/N with high quality without using a filter circuit of complicated configuration and to improve accuracy for positioning a head by respectively independently provid ing a gap for read/write and a gap for servo. CONSTITUTION:A gap 10 for read / write of a narrow gap length [gap (a)] for high density, a gap 11 for servo of a wide gap length [gap (b)] for low density and a gap separating layer 12 are provided [gap (a) < gap (b)]. The gap 11 for servo is arranged at prescribed intervals to the gap 10 for read / write, for example, in an hourly delayed position in a rotating direction A of a recording medium. The gap 11 for servo is formed so as to obtain pre scribed azimuth to the gap 10 for read / write. Thus, without using the filter circuit in the complicated configuration, the data and servo information can be respectively read with the high quality, and the accuracy for positioning the head can be improved.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a head device and a head positioning control device for a data recording/reproducing device using a recording medium having a multilayer recording area in a surface layer and a deep layer. .

(Prior Art) In recent years, various developments have been made in, for example, floppy disk drives (FDD) as storage capacity increases (higher density). In general, to increase storage capacity, methods are used to increase the recording density in the circumferential direction (linear recording density) of the tracks of the recording medium or methods to increase the density in the radial direction (track density) of the tracks. There is.

In order to increase the track density, it is necessary to improve the positioning accuracy when positioning the head on the target track. In conventional FDDs, the seek 11 control of the head is performed according to the absolute distance from the reference position on the recording medium. For this reason, if eccentricity of the recording medium or deviation of the reference position between different FDDs occurs due to fluctuations in temperature and humidity, head positioning accuracy decreases and it is difficult to increase track density.

As a solution to such problems, there is a method in which servo information (position information) is recorded in advance on a recording medium and the servo information is used to control the positioning of the head. This servo system usually uses a sector servo system in which servo information is recorded in a part of a sector (a data recording unit that partitions a track). However, the sector servo method has the following drawbacks: firstly, the efficiency of formatting the recording medium is reduced; secondly, the degree of freedom in formatting is reduced; and thirdly, servo information can only be obtained intermittently.

That is, since servo information is recorded in a part of the sector, the data area is reduced by that amount, and it is impossible to perform a new format from the first format in order to protect the servo information.

For this reason, in recent years, a method has been developed that uses a recording medium with a multilayer structure of recording areas in the surface and deep layers, recording normal high-density data in the surface layer and recording low-density servo information in the deep layer. . The deep region is a layer below the surface region, and constitutes a servo surface with respect to the data surface of the surface layer. By the way, data on the surface layer and servo information on the deep layer are read by a single gap of the head. In this case, taking advantage of the fact that the data at the time of reading is of high frequency and the servo information is of low frequency, the signal read out by a single gap can be separated by a filter, and the data and servo information can be processed separately. Furthermore, when writing data, since the head gap has a small gap length (for high density) compared to the magnetic film thickness of the recording medium, data is written only on the surface layer and does not affect the servo information in the deep layer.

(Problems to be Solved by the Invention) In order to achieve high density FDDs, there is a method in which servo information is recorded in a deep layer of a recording medium and this servo information is used to improve head positioning accuracy. however,
Because of the single gap, servo information is read using the same gap even during a data write operation, which has the drawback of lowering the S/N ratio of the servo information. Further, at the time of reading, a filter is required to separate the data and servo information as described above, but a filter circuit with a complicated configuration is required for good separation. Furthermore, since both the S/N ratio of data and the S/N ratio of servo information are simultaneously constrained by the gap width, it is difficult to set an optimal gap width.

An object of the present invention is to read out data and servo information with high quality, without using a filter circuit with a complicated configuration, in a system that uses a recording medium that records data on the surface layer and servo information on the deep layer. An object of the present invention is to provide a head device and a head positioning control device for a data recording/reproducing apparatus that can improve head positioning accuracy.

[Structure of the Invention] (Means and Effects for Solving the Problems) The present invention provides a recording medium that is arranged so as to have a predetermined azimuth in the circumferential direction of the recording medium with a read/write gap and a predetermined interval. This head device includes a servo gap for reading/writing servo information to a deep region opposite to a surface region of the head.

The present invention also includes positioning control means for positioning the head to a target track in a surface area of the recording medium based on servo information read from a deep area of the recording medium by a servo gap of the head device. This is a head positioning control device.

With this configuration, it is possible to read data and servo information from the surface layer and deep layer of the recording medium with high quality using an optimal gap. Furthermore, since it is possible to prevent the S/N ratio of servo information from decreasing when writing data, it is possible to perform head positioning operations with high precision.

(Example) The present invention will be described in detail below with reference to the drawings. FIG. 1 is a plan view for explaining the structure of a head device according to the same embodiment, FIG. 2 is a sectional view for explaining the structure of a recording medium according to the same embodiment, and FIG. 3 is a plan view for explaining the structure of a recording medium according to the same embodiment. FIG. 2 is a block diagram for explaining the configuration of a related head positioning control system. As shown in FIG. 1, the head device of this embodiment has a narrow gap length (gap a) for high density, a gap for read/write (IO1), a wide gap length (gap a) for low density.
b) Servo gap 11 and gap separation layer 1
2 (gap a<gapb). The servo gap 11 is arranged at a predetermined interval with respect to the read/write gap 10, for example, at a position delayed in time in the rotation direction A of the recording medium. In addition, the servo gap 11 is a read/write gap IO.
It is formed to have a predetermined azimuth with respect to the azimuth.

Further, as shown in FIG. 2, the recording medium 20 of the same embodiment has a surface layer data area 1 formed on a substrate 13 which is a base.
The medium has a multilayer structure consisting of a deep servo region 15 and a deep servo region 15 below it. The surface data area 14 is a surface area where high-density data is magnetically recorded by the read/write gap lO of the head. In the deep servo area 15, pre-recorded, for example, two-phase servo information Fl, F2 is recorded, and the servo information F1. F2 is a deep region read out by the servo gap 11.

On the other hand, as shown in FIG.
) has a servo circuit 23 that processes servo information read out by the servo gap 11. The SO head 21 and the S1 head 22 are mounted on a carriage 24 that moves in the radial direction of the recording medium 20. The servo circuit 23 outputs a control signal for positioning the head to a target track on the recording medium 20 to the carriage drive circuit 25 based on the servo information from the servo gap 11. The carriage drive circuit 25 supplies a drive current according to a control signal from the servo circuit 23 to the motor (for example, a voice coil motor) of the carriage 24 to move the carriage 24 to a target position. Here, the recording medium 20 is rotated by a spindle mechanism 28.

The read/write circuit 26 reproduces the data read by the head 21 or 22 through the read/write gap lO, and also supplies the head with a write current according to the write data transferred from the FDC (controller) 27. A recording magnetic field is generated from the read/write gap 10.

Next, the operation of this embodiment will be explained. First, the head (for example, the S1 head 22) seeks to the target track (surface data area 14) of the recording medium 20, and the target track (
It is positioned at the center of track 20a) in FIG. In this case, servo information is read from the deep servo area 15 of the recording medium 20 through the servo gap 11 of the head and output to the servo circuit 23 . The servo circuit 23 generates a speed signal from the servo information, and executes seek control (speed control) of the head based on this speed signal. That is, the carriage drive circuit 25 supplies the motor of the carriage 24 with a drive current according to the control signal from the servo circuit 23, and moves the carriage 24 to the target position.

When the head is sought to the target track, it performs, for example, a data read operation. That is, the head reads data recorded in the surface data area 14 of the recording medium 20 using the read/write gap IO, and outputs the read signal to the read/write circuit 26. At this time, at the same time as the data read operation, the servo gap 1 of the head is
1, servo information is being read from the deep servo area 15 of the recording medium 20. The servo circuit 23 executes a control operation for positioning the head to the center of the target track (position control) based on servo information from the servo gap 11. In this case, since the servo gap 11 and the read/write gear lO have mutual azimuth, so-called azimuth loss prevents crosstalk between the read signal from the read/write gap 10 and the servo information. be able to. Therefore, when reading data, S
High quality servo information with a high /N ratio can be read.

On the other hand, when the head performs a data write operation, a recording magnetic field is generated from the read/write gap 10 to the surface data area 14 of the recording medium 20. in this case,
Since the read/write gap 10 has a narrow gap length for high density, the recording magnetic field does not reach the deep servo area 15. Therefore, the data write operation can be performed reliably without affecting the servo information in the deep servo area 15.

In this way, data is read from or written to the surface data area 14 of the recording medium 20 using the read/write gap IO. On the other hand, servo information is read from the deep servo area 15 of the recording medium 20 through the servo gap 11 having an azimuth. When reading this servo information, the servo gap 11, which is a gap different from the read/write gap 10 and has an azimuth, is used, so high quality servo information with a high S/N ratio can be read. I can do it.

Furthermore, since the data and servo information are read out through the respective gaps 10.11, it is possible to eliminate the need for a complex filter circuit for separating the data and servo information.

Further, by using the servo gap 11 having a wide gap length, it becomes possible to rewrite the servo information in the deep servo area 15 of the recording medium 20 (so-called self-servo write). In this case, as a matter of course, the surface data area 14 of the recording medium 20 is affected, so this is limited to the case where the servo information is rewritten before formatting the surface data area 14. Additionally, there is a gap 10 corresponding to data and servo information. 11, it is possible to set the optimum gap width according to each S/N ratio of data and servo information.

[Effects of the Invention] As detailed above, according to the present invention, in a system using a multilayer recording medium in which data is recorded on the surface layer and servo information is recorded in the deep layer, the gap for read/write and the gap for servo By providing each gap independently, there is no need to use a complex filter circuit.
Data and servo information can each be read out with high quality at a high S/N ratio. Therefore, when reading or writing high-density data, it is possible to use high-quality servo information to control head positioning with high precision.

Furthermore, since the FDD can perform so-called self-servo writing by using a servo gap with a wide gap length, the performance of the FDD can be improved.

[Brief explanation of the drawing]

FIG. 1 is a plan view for explaining the configuration of a head device according to an embodiment of the present invention, FIG. 2 is a cross-sectional view for explaining the configuration of a recording medium according to the embodiment, and FIG. FIG. 2 is a block diagram for explaining the configuration of a head positioning control system according to an example. DESCRIPTION OF SYMBOLS 10... Read/write gap, 11... Servo gap, 20... Recording medium, 23... Servo circuit, 26... Read/write circuit.

Claims (2)

[Claims] (1) A read/write gap for reading/writing data to the surface area of the recording medium, and a predetermined azimuth in the circumferential direction of the recording medium at a predetermined interval from the read/write gap. A head device for a data recording/reproducing device, comprising: a servo gap for reading/writing servo information to/from a deep region opposite to the surface region of the recording medium; . (2) A read/write gap for reading/writing data to the surface area of the recording medium and for reading servo information recorded in the deep area opposite to the surface area of the recording medium. a head having a servo gap, and a head having a servo gap for positioning the head to a target track in the surface area of the recording medium based on servo information read from the deep area of the recording medium by the servo gap. 1. A head positioning control device for a data recording/reproducing device, comprising: positioning control means.