JPH05307707A - Method and device for magnetic recording and reproducing - Google Patents

Abstract

PURPOSE:To prevent distortion of a reproducing waveform without working a bias magnetic field on a magnetoresistance(MR) head with regard to the method and device for recording a magnetic recording medium with an inductive head and reproducing it with the MR head. CONSTITUTION:1st and 2nd inductive heads 21 and 26 are provided parallel in the widthwise direction of a track 32 of the magnetic recording medium 31. A magnetic field of the same phase or the reverse phase is generated by the 1st and 2nd inductive heads 21 and 26, and the track is magnetized in the same direction or the reverse direction, and then a magnetic field of the whole width of the track is synthesized and detected by the MR head 35.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording / reproducing method and a magnetic recording / reproducing apparatus, and more particularly to recording on a magnetic recording medium with an inductive head to obtain a magnetic resistance (MR).
The present invention relates to a magnetic recording / reproducing method and a magnetic recording / reproducing apparatus for reproducing with a (c Resistance) head.

In recent years, data is recorded on a magnetic recording medium such as a magnetic disk or a magnetic tape by applying a predetermined magnetic field according to the data to be recorded, and the residual data generated on the magnetic recording medium by this data recording. A magnetic recording / reproducing apparatus that reproduces recorded data based on a magnetic field generated by magnetization is widely supplied to the market.

In such a magnetic recording / reproducing apparatus, it is necessary to reproduce the magnetic field of the magnetic recording medium into a predetermined signal without distortion.

[0004]

2. Description of the Related Art Conventionally, as a magnetic recording / reproducing apparatus,
A coil (inductive head) formed by winding a lead wire around a magnetic pole is used as a recording-only head, and a predetermined current is applied to the lead wire of the inductive head to generate a magnetic field.
By applying the magnetic field to the magnetic recording medium, remanent magnetization is generated to record data, and an MR head whose resistance value changes when a magnetic field is applied is used as a read-only head to record data. An apparatus is known which reproduces data according to the magnetization state of the surface of the magnetic recording medium.

FIG. 7 is a diagram showing the magnetic field characteristics of a magnetoresistive element (MR element) used in an MR head.

In the figure, the waveform indicated by the broken line is the amplitude of the residual magnetization generated in the magnetic recording medium when data is recorded on the magnetic recording medium, and the magnetic field generated by the residual magnetization is applied to the MR element. In this case, the resistance value of the MR element is shown.

Generally, when binary data is recorded on a magnetic recording medium, since the magnetic recording medium has a hysteresis characteristic with respect to magnetization, the data is recorded by saturation recording with an inductive head, resulting in residual magnetization. It is done by the difference of the direction.

On the other hand, as shown in the same figure, since the MR element has a characteristic symmetrical with respect to the direction of the magnetic field, the maximum magnetic field is applied in the opposite direction to the magnetic recording medium to perform saturation recording in the opposite direction. When this is done, the resistance values of the MR element with respect to those residual magnetizations become equal. Also, due to the characteristics of the MR element, the rate of change of its resistance value is small in the region where the applied magnetic field is weak,
The linearity with respect to the applied magnetic field is also poor.

For this reason, conventionally, in a magnetic recording / reproducing apparatus for reproducing information by an MR head, an appropriate bias magnetic field (Hb in the figure) is applied to the MR head to set an operating point, and resistance to the applied magnetic field is set. By increasing the rate of change of the value, the linearity of the applied magnetic field and the electric resistance value is improved, and at the same time, the data can be reproduced from the residual magnetic field when the opposite magnetic field is applied.

FIG. 8 shows a perspective view of an example of applying a bias magnetic field to the MR head. In the figure, reference numeral 1 denotes an MR head, to which a constant current source 3 is connected in order to detect a resistance value which changes according to the residual magnetization of the magnetic recording medium as an electric signal. Further, the MR head 1 is laminated with a SAL (soft magnetic) film 2 which generates a magnetic force by passing an electric current, whereby a bias magnetic field is applied.

[0011]

However, in the above-described conventional magnetic recording / reproducing apparatus, the bias magnetic field applied to the MR head 1 is adjusted by the thickness of the SAL film 2, so that the SAL
When the film thickness is different, the operating point of the MR head changes,
The resistance value fluctuation amplitude of the R element fluctuates and the reproduced waveform is distorted, which is an obstacle to high density recording.

The present invention has been made in view of the above points, and a magnetic recording / reproducing method and a magnetic recording / reproducing method which prevent distortion of a reproduced waveform and enable high density recording without applying a bias magnetic field to an MR head. It is an object to provide a recording / reproducing device.

[0013]

The above-mentioned problems are solved by recording binarized data in a magnetic recording medium as shown in the principle diagram of FIG. 1, and by recording the data based on the magnetic field generated by the residual magnetization of the magnetic recording medium. In the first step 11, in the magnetic recording / reproducing method of reproducing the data, a predetermined number of in-phase or anti-phase parallel to the track of the magnetic recording medium are arranged in parallel in the track width direction of the magnetic recording medium in accordance with each bit value of the data. A magnetic field is applied to sequentially record the bit values on the magnetic recording medium, and the second step 12
Then, by the predetermined number of magnetic fields, the magnetic field generated by the residual magnetization generated in parallel with the tracks is synthesized and detected,
In the third step 13, it is solved by converting the detected magnetic field into a predetermined signal according to its strength.

[0014]

According to the above structure, each bit value of the data is recorded on the track of the magnetic recording medium as in-phase or anti-phase remanent magnetization, and this remanent magnetization is in-phase or anti-phase saturation recording. Therefore, a stable magnetic field is generated regardless of the hysteresis characteristic of the magnetic recording medium.

When the remanent magnetization recorded on the track is combined over the entire track width, the remanent magnetization is strengthened when magnetized in the same phase, and is canceled and weakened when magnetized in the opposite phase. Each bit value can be regarded as being recorded as a magnetic field strength difference in the track of the magnetic recording medium, and the magnetic field strength is binarized with high accuracy.

Therefore, when the magnetic field strength generated in the full track width of each magnetic recording medium is converted into a predetermined signal, a binary signal corresponding to each bit value of the data is obtained.

[0017]

2 is a perspective view of an embodiment of a magnetic recording / reproducing apparatus according to the present invention. In the figure, 21 and 26
Shows the first and second inductive heads. These are the first and second inductive heads 21 and 26 corresponding to the first and second recording heads that constitute the data recording means, and the magnetic poles 22 and 27 having high magnetic permeability,
It is constructed by winding coils 23 and 28. The terminals 24, 25, 29, 30 at both ends of the coils 23, 28 are
It is connected to a current source (not shown), and in-phase or anti-phase currents are supplied according to each bit value of the binary data to be recorded.

For example, terminals 24 and 25 and terminals 29 and 3
When an in-phase current flows through the coils 23 and 28 via 0, an in-phase magnetic field is generated in the coils 23 and 28, and when an anti-phase current flows, an anti-phase magnetic field is generated.

Therefore, in-phase or anti-phase magnetic fields are applied to the magnetic poles 22, 27, and the first and second inductive heads 21, 26 are in-phase or anti-phase magnetic fields according to the bit value of the data. To occur.

In the apparatus of this embodiment, each bit value of the binarized data to be recorded is represented by "0" and "1" for convenience, and when recording the bit value "0", Second
A magnetic field of the same phase is generated in the inductive heads 21 and 26, and a magnetic field of the opposite phase is generated when the bit value "1" is recorded.

In the figure, 31 indicates a magnetic recording medium. When a magnetic field is applied to the surface of the magnetic recording medium 31, it is magnetized along the lines of magnetic force of the applied magnetic field, resulting in residual magnetization that generates a magnetic field according to the strength of the applied magnetic field. Further, the magnetic recording medium 31 is divided into tracks 32 as a data recording and reproducing area.

On the other hand, as shown in the figure, the first and second inductive heads 21 and 26 are arranged in parallel in the width direction of the track 32. Therefore, in order to record data, the first and second inductive heads 21, 2
When a magnetic field is generated in 6, the remanent magnetization due to the magnetic field applied from the first inductive head 21 and the remanent magnetization due to the magnetic field applied from the second inductive head 26 are parallel to each other in the width direction on the track 32. Occurs.

Therefore, when the first and second inductive heads 21 and 26 generate in-phase magnetic fields (bit value "0"), like the track unit 33 in FIG.
The residual magnetic fields in the same direction are generated in parallel in the width direction of the track 32.

When the first and second inductive heads 21 and 26 generate magnetic fields having opposite phases (bit value "
1 "), the residual magnetic field is generated in the opposite direction in parallel with the width direction of the track 32 in the same manner as the track unit 34 in the figure. In the figure, the white arrow indicates the direction of the residual magnetization. ing.

Further, in the figure, reference numeral 35 denotes an MR head which is a reproducing head of the data reproducing means, and is a track 3
It has a width substantially equal to the total width of the track 2 and is arranged in parallel with the width direction of the track 32 as shown in FIG. Further, the MR head 35 is driven by a direct current by a constant current source (not shown), and the applied magnetic field strength is
It is converted into an electric signal.

FIG. 3 is a diagram showing the characteristics of the MR head of this embodiment with respect to the magnetic field. As shown in the figure, the MR head 35 of the present embodiment has a characteristic symmetrical with respect to the direction of the magnetic field, like the conventional MR head shown in FIG. 7, and the resistance value increases as the strength of the applied magnetic field increases. Is reduced.

On the other hand, the MR head 35 simultaneously detects the magnetic field generated by the entire width of the track 32. Therefore, when the tracks 32 are magnetized in the same direction over the entire width, the magnetic field is detected, and the resistance value becomes according to the magnetic field strength (“H” in FIG. 3). When the track 32 is divided into two in the width direction and magnetized in the opposite direction, the magnetic fields cancel each other out, and the resistance value becomes equivalent to that when no magnetic field is applied.

Therefore, the MR head 35 of the apparatus of this embodiment is used.
However, when the bit values recorded on the track 32 are sequentially reproduced, a binarized magnetic field detection waveform is obtained as shown in FIG.

FIG. 4 is a diagram showing an example of a reproduction signal of the apparatus of this embodiment. As described above, in the apparatus of this embodiment, the resistance value of the MR head 35 takes a binarized value according to the bit value recorded on the track 32. Therefore, by converting this resistance value into an electrical signal,
As shown in the figure, the bit values "0" and "1" can be easily reproduced.

In the apparatus of this embodiment, the truck 3
The magnetic field due to the residual magnetization of 2 can be directly converted into the resistance value of the MR head 35. Therefore, the bias magnetic field applied to the MR head, which is required in the conventional device, is unnecessary, and the reproducing mechanism can be simplified. Also, since the playback signal waveform does not change due to bias,
Signals are not distorted and high-accuracy reproduction is possible.

FIG. 5 is a perspective view showing another embodiment of the device of the present invention. In the figure, reference numerals 41 and 44 denote the first and second inductive heads of the apparatus of this embodiment.

First and second inductive head 41
And 44 have magnetic poles 42 and 45 with coils 43 and 46
Is wound. The coils 43 and 46 are composed of the lead wire 50 and correspond to the first and second magnetic field generating units.

The end portion of the lead wire 50 on the first inductive head 41 side is the first terminal 47 and the other end portion is the third terminal 49, and the portion of the lead wire 50 connecting the coils 43 and 46. The second terminal 48 is pulled out from this to form three terminals.

Therefore, current control for generating a desired magnetic field in the first and second inductive heads 41 and 44 can be performed by the three terminals of the first to third terminals 47 to 49.

For example, when in-phase currents are passed through the first and second inductive heads 41 and 44, the third terminal 49 is used.
A current always flows in, and the first terminal 47 serves as a current outflow terminal. Further, when a reverse-phase current is passed through the first and second inductive heads 41 and 44, the first terminal 47
Also as the current inflow terminal and the second terminal 48 as the current outflow terminal, the current can be controlled by the three terminals.

Therefore, it is possible to simplify the structure of the current source that supplies the first and second inductive heads 41 and 44 with a current according to the bit value of the data to be recorded. Also,
The first and second inductive heads 41 of this embodiment,
Since 44 forms the two coils 43 and 46 with one lead wire 50, the number of parts can be reduced.

FIG. 6 is a circuit diagram of another embodiment of the device of the present invention, showing the circuit diagrams of the first and second inductive heads.

In the figure, 51 and 52 are coils of the inductive head corresponding to the first and second magnetic field generating portions. Both ends of the coil 52 are connected to the connecting wires 60, 6 respectively.
1 is connected to the first and second terminals 58 and 59. Both ends of the coil 50 are respectively connected to the output terminals of the full-wave rectifier circuit 53, which is an in-phase and anti-phase generator, and the input terminals of the full-wave rectifier circuit 53 are the first and second terminals 58, 58, respectively.
It is connected to 59. The full-wave rectifier circuit 53 is composed of four diodes 54 to 57 that are bridge-connected, and always uses the coil 5 regardless of the polarities of the first and second terminals 58 and 59.
1 is supplied with a constant current.

Therefore, when the polarities of the first and second terminals 58 and 59 are reversed, only the direction of the current supplied to the coil 52 is reversed, and the currents flowing through the coils 51 and 52 are easily in-phase or anti-phase. Can be

Therefore, the structure of the magnetic field generating means can be further simplified as compared with the case of the other embodiment.

[0041]

As described above, according to the present invention, the data recorded in the track of the magnetic recording medium can be reproduced only by converting it into a predetermined signal according to the magnetic field strength generated by the full width of the track. No complicated mechanism is required for reproducing the data from the recording medium.

Further, since the magnetic field intensity generated by the magnetic recording medium is simply converted into a predetermined signal, the reproduced signal is not distorted, and binary determination of the magnetic field recorded at a higher density than in the past is possible. Therefore, it is particularly suitable for a magnetic recording / reproducing method for recording / reproducing with high accuracy.

[Brief description of drawings]

FIG. 1 is a principle diagram of the present invention.

FIG. 2 is a perspective view of an embodiment of the device of the present invention.

FIG. 3 is a diagram showing characteristics of a magnetoresistive head of an embodiment of the present invention device with respect to a magnetic field.

FIG. 4 is a diagram showing an example of a reproduction signal of an embodiment of the device of the present invention.

FIG. 5 is a perspective view of another embodiment of the device of the present invention.

FIG. 6 is a diagram showing a circuit diagram of another embodiment of the device of the present invention.

FIG. 7 is a diagram showing magnetic field characteristics of a magnetoresistive element.

FIG. 8 is a perspective view of an example of applying a bias magnetic field to a magnetoresistive head.

[Explanation of symbols]

 21, 41 First inductive head 23, 28, 43, 46 Coil 26, 44 Second inductive head 31 Magnetic recording medium 32 Track 35 Magnetoresistive head 47, 58 First terminal 48, 59 Second terminal 49 49th 3 terminal 50 lead wire 53 full-wave rectifier circuit 54-57 diode

Claims (5)

[Claims] 1. A magnetic recording medium (3
In the magnetic recording / reproducing method for recording data in 1) and reproducing the data based on the magnetic field generated by the residual magnetization of the magnetic recording medium (31), the magnetic recording medium (3) is recorded according to each bit value of the data.
By applying a predetermined number of in-phase or anti-phase magnetic fields parallel to the width direction of the track (32) to the track (32) of 1),
The bit value was sequentially recorded on the magnetic recording medium (31), and the magnetic field generated by the residual magnetization generated in parallel with the track (32) was synthesized and detected by the predetermined number of magnetic fields and detected. A magnetic recording / reproducing method characterized by converting a magnetic field into a predetermined signal according to its strength. 2. A binarized data is recorded on a magnetic recording medium (3
1. A magnetic recording / reproducing apparatus comprising: a data recording unit for recording in 1); and a data reproducing unit for reproducing data by converting a magnetic field generated by residual magnetization of the magnetic recording medium (31) into a predetermined signal. The data recording means are arranged in parallel in the width direction of the track (32) of the magnetic recording medium (31), and can generate magnetic fields independently of each other, the first and second recording heads (21, 26). ) Is used to apply a magnetic field of in-phase or anti-phase magnetic field to the track of the magnetic recording medium (31) according to each bit value of the data, and the data reproducing means is A reproducing head (35) is provided, which detects a magnetic field generated by the residual magnetization of the recording medium (31) by synthesizing it over the entire width of the track (32) and outputting a signal according to the intensity of the detected magnetic field. Magnetic recording and reproducing apparatus, characterized in that. 3. The first and second recording heads (2)
The first and second magnetic field generators (43, 46) capable of generating magnetic fields independently of each other and the magnetic fields generated by the first and second magnetic field generators (43, 46). The first and second magnetic poles (42, 45) that propagate and are applied to the track (32) of the magnetic recording medium (31).
The in-phase or anti-phase magnetic field is generated by driving the second magnetic field generator (43, 46) with three input terminals (47-49). Magnetic recording and reproducing device. 4. The first and second recording heads generate first and second magnetic field generators (51, 52) capable of independently generating magnetic fields, and magnetic fields generated by the magnetic field generators. Generated in-phase or anti-phase magnetic fields in the first and second magnetic field generators (51, 52) that propagate and are applied to the tracks of the magnetic recording medium and the first and second magnetic field generators (51, 52). 3. An in-phase / out-of-phase generating section (53, 60, 61) for causing the in-phase / out-of-phase generating section (53, 60, 61) to have two input terminals (58, 59). The magnetic recording / reproducing apparatus described. 5. A connection line (60, 61) connecting the in-phase and anti-phase generator to the two input terminals (51) of one of the first and second magnetic field generators, and the two inputs. Full-wave rectify the input signal supplied to the terminals (58, 59),
Full-wave rectifier circuit (5 supplied to the other magnetic field generator (52)
The magnetic recording / reproducing apparatus according to claim 4, wherein the magnetic recording / reproducing apparatus is configured in 3).