JPH08235548A - Information reading and writing device - Google Patents

Abstract

PURPOSE: To shorten the time together with the switching of a recording operation and reproducing operation by optimizing the arrangement of recording elements and reproducing elements from characteristics in terms of magnetic recording. CONSTITUTION: A magnetic reluctance effect element 31 is used as the reproducing element and is held by magnetic shielding layer 32, 33. Further, an induction type head 34 is laminated as the recording element. A lower magnetic pole is commonly used as an upper shielding layer 33 and an upper magnetic pole 36 is laminated via a gap layer 35 on the lower magnetic pole in the recording element. The geometrical center in the track width direction of the magnetic reluctance effect element 31 is the center of the spacing of electrodes 37 existing on both sides of the element. The geometrical center of the recording head is the center of the magnetic pole width of the upper magnetic head. Then, the spacing between the geometrical centers of the recording element and the reproducing element in the direction normal to a straight line connecting the axis of an actuator and the recording element is L0. The degradation in the throughput of the data based on the switching of the recording operation and the reproducing operation in the track is minimized in such a manner.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the field of disk drives, and more particularly to the arrangement of recording elements and reproducing elements on data tracks.

[0002]

2. Description of the Related Art A magnetic disk drive device comprises a rotary medium, an actuator having a rotary shaft, and a slider including a reproducing element and a recording element associated with the actuator. Here, when the slider moves to a desired track on the medium, its locus describes an arc centered on the axis of the actuator. When either the recording element or the reproducing element is placed on a particular track, the other element is off the track. The amount by which one element deviates varies as a function of track radius. This track misalignment affects the device characteristics, and as a method for preventing this, when the recording operation or the reproducing operation is switched to the other operation in the same track, the recording element or the reproducing element comes on the desired track. The repositioning method has been adopted. As a solution for shortening the time required for this repositioning, a technique for arranging a recording element and a reproducing element so that the repositioning distance with respect to all the tracks in a drive is minimized is disclosed in JP-A-4-232610. ing. In this prior art, (1) the repositioning amount is obtained by measuring the amount of positional deviation between the recording element and the reproducing element at several track positions during the manufacture of each drive.
(2) An offset is given to the arrangement of the recording element and the reproducing element in order to minimize the moving distance of the slider accompanying the switching between recording and reproduction and improve the data throughput.
It is disclosed.

However, regarding the method for obtaining the optimum offset amount, a technique for obtaining the offset amount from a geometrical arrangement is disclosed, but a technique from the magnetic recording viewpoint including the characteristics of the head medium is disclosed. Didn't.

[0004]

SUMMARY OF THE INVENTION In the present invention, in order to reduce the time required for switching between the recording operation and the reproducing operation,
It is intended to provide an information reading / writing device in which the arrangement of a recording element and a reproducing element is optimized from the characteristics of magnetic recording.

[0005]

A value obtained by projecting a positional deviation between a recording element center and a reproducing element center on the magnetic recording in the innermost part of the medium in the radial direction of the medium and a recording element center on the magnetic recording in the outermost part of the medium. The recording element and the reproducing element are arranged so that the positional deviation amount of the reproducing element center becomes equal to the value projected in the radial direction of the medium.

[0006]

The magnetic recording distance between the recording center and the reproduction center at the innermost and outermost peripheral portions of the medium and the magnetic recording distance between the recording center and the reproduction center at the outermost peripheral portion are projected in the radial direction of the medium. Since the recording head and the reproducing head are arranged so that the distances are equal, the average repositioning distance required for aligning the recording element and the reproducing element in the entire outermost and innermost areas of the medium is minimized. Therefore, it is possible to shorten the time required for switching the recording operation and the reproducing operation.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a schematic diagram of a disk drive. Here, the disk drive is a medium 10 having a center of rotation 11.
And a rotary actuator 12 having a rotary shaft 13
And a head slider 14 having a read / write element at the tip of the actuator. The head slider at the tip moves on a desired recording track on the medium while drawing an arc around the rotation axis 13. FIG. 2 shows the relationship between the innermost peripheral position 21 and the outermost peripheral position 22 of the head on the medium and the yaw angle. Here, the yaw angle of the innermost circumference is θ
1 and the yaw angle of the outermost circumference is indicated by θ2. The yaw angle is defined as an angle formed by a tangent line in the medium movement direction and a straight line connecting the recording element or the reproducing element at the head tip from the rotary shaft 13 of the actuator. Here, the value of the yaw angle at each position is the distance between the medium rotation center 11 and each position of the medium, that is, the radius,
The yaw angle is uniquely determined from the distance between the rotation center of the medium and the rotation center 13 of the actuator 11, the distance between the rotation axis of the actuator and the element at the tip of the slider, and these distances.

FIG. 3 is a view of the recording element and the reproducing element at the end of the slider at the tip of the actuator as seen from the air bearing surface side. The rotary shaft of the actuator is located at the bottom of the figure, and the slider is omitted. In the figure, a magnetoresistive effect element 31 is used as a reproducing element,
This is sandwiched between the magnetic shield layers 32 and 33, and an inductive head 34 is further stacked as a recording element. In the recording element, the lower magnetic pole also serves as the upper shield layer 33, and the upper magnetic pole 36 is laminated on the upper shield layer 33 via the gap layer 35. In the figure, the geometric center of the magnetoresistive effect element in the track width direction is the center of the distance between the electrodes 37 on both sides of the element, and the geometric center of the recording head is the center of the magnetic pole width of the upper magnetic head. . Therefore, the distance between the geometric centers of the recording element and the reproducing element in the direction of the straight line connecting the axis of the actuator and the recording element defined in this patent is L0 shown in FIG. The distance between the geometric center of the reproducing element and the magnetic recording center in the track width direction is ΔR. The method of obtaining the magnetic recording center and the value will be described later.
Further, the magnetic recording distance between the recording element and the reproducing element in the linear direction connecting the axis of the actuator and the recording element is as shown by b in the figure, and its value and the method of obtaining it will be described later.

Here, a head having a shape as shown in FIG.
When the yaw angle θ is present on the disc of FIG. 2, the amount of magnetic recording misalignment between the recording element and the reproducing element is expressed by the following equation.

[0010]

## EQU1 ## (L ₀ + ΔR) cos θ−bsin θ or

[0011]

Difference Equation 2] of (L ₀ -ΔR) cosθ-bsinθ where the number 1 and number 2 is the sign of [Delta] R. This is because the distance ΔR between the geometric center of the reproducing element and the magnetic recording center in the track width direction systematically changes depending on the direction of magnetization of the magnetoresistive effect element and the direction of the current for output detection. By minimizing the positional deviation between recording and reproduction over the entire surface from the innermost circumference to the outermost circumference, it is possible to shorten the time required to move the head when switching between the recording operation and the reproducing operation. This can be realized by setting the same amount of positional deviation between the innermost circumference and the outermost circumference and obtaining L0 so that the deviation directions are opposite. That is, it can be realized by setting L0 so that the amount of displacement at the middle position is zero. This is shown in the following equation.

[0012]

## EQU3 ## (L ₀ + ΔR) cos θ1−bsin θ1 = bsin θ2− (L
₀ + ΔR) cos θ2 or

[0013]

(4) (L ₀ −ΔR) cos θ1−bsin θ1 = and bsin θ2−
(L ₀ −ΔR) cos θ 2 Here, the value of b, that is, the magnetic recording interval between the recording element and the reproducing element in the linear direction connecting the axis of the actuator and the recording element is determined as follows. Play back after recording,
The amount of magnetic recording deviation between the recording element and the reproducing element in the track width direction is measured while changing the yaw angle, and the yaw angle dependence of the deviation amount is evaluated. Here, the magnetic recording deviation amount is the difference between the output peak and the recording center position in the output off-track distribution obtained by off-tracking the head. In the yaw angle dependence of the shift amount, the slope of the change in the shift amount with respect to the tangent of the yaw angle becomes the value of the magnetic recording distance b between the recording element and the reproducing element.

A head (about 2.0 μm to 5.0 μm) having a geometrically different distance between the recording element and the reproducing element is used, and the medium coercive force (2200 Oe to 3500 Oe) and the flying height (medium magnetic film and head element). Distance from surface: 40 nm to 80
nm), the off-track output distribution was obtained using the yaw angle as a parameter, and the value of the magnetic recording distance b was measured. In both cases, the geometrical dimensions and dimensions from the magnetoresistive effect element to the gap surface side of the upper magnetic pole were measured. Measurement accuracy (± 0.1 μm)
It was almost the same within. Therefore, it is found that the magnetic recording distance b between the recording element and the reproducing element in the linear direction connecting the axis of the actuator and the recording element corresponds to the geometrical dimension from the magnetoresistive effect element to the gap surface side of the upper magnetic pole. It was

Next, the distance ΔR between the geometric center of the reproducing element and the magnetic recording center in the track width direction was examined.
It is already known that in a head using a magnetoresistive effect element, the center of reproduction sensitivity may deviate from the geometric center. In the present invention, the relationship between the width of the magnetoresistive effect element in the signal magnetic field penetration direction (hereinafter referred to as element height) and ΔR was clarified experimentally. The geometric track width was fixed at 3 μm, and the device height was changed from 0.8 μm to 5.0 μm to evaluate ΔR. It can be seen that ΔR increases as the element height increases, and that ΔR tends to saturate at a certain value. The slope of the increase in ΔR is approximately 1/4 of the element height. Also, the value of the element height that saturates tends to depend on the recording density of the signal magnetic field at the time of measurement. When the recording density increases, ΔR saturates the element height decreases, and conversely when the recording density decreases, ΔR decreases. The element height at which is saturated becomes large. The relationship between the recording density and the height of the element that saturates approximately corresponds to the penetration depth of the signal.

It is generally known that in order to operate the magnetoresistive effect element with high efficiency, it is preferable to make the element height approximately equal to the signal magnetic field penetration depth. Therefore, in order to perform an appropriate operation according to the recording density, it is necessary to make the element height equal to the magnetic field penetration depth. If this is done, the value of ΔR described above is before saturation occurs. Is proportional to about 1/4 of the element height.

Next, a case will be described in which one medium in the disk drive is sandwiched and two upper and lower heads are combined. Since the upper and lower two heads face each other and move simultaneously about the rotation axis of the actuator, when the heads are manufactured on the wafer substrate, the upper and lower heads have a magnetic recording-like recording element center and a reproducing element center in a line-symmetric relationship. There is a need. On the other hand, the deviation ΔR between the geometric center and the magnetically recording center in the reproducing element shifts in the same direction if the film forming conditions of the element and the magnetic field application process after formation are the same. It is not impossible to shift ΔR in the opposite direction by changing the manufacturing conditions and the magnetic field application method with the upper and lower sliders,
The process becomes complicated, and in order to ensure its reproducibility, it is necessary to improve the process accuracy and it becomes complicated. Therefore, in order to form the upper and lower heads under the same film forming conditions and the same magnetic field treatment, heads having different geometrical distances L0 between the recording element and the reproducing element are prepared in advance for the upper and lower heads. It is necessary to fabricate one set of heads by combining them. For this purpose, the sign of the value obtained by adding ΔR to the geometrical interval L0 of either one of the heads and the value obtained by adding ΔR to the geometrical interval L0 of the other head is opposite, and the absolute value is approximately the same. It is necessary to arrange the recording element and the reproducing element so that they are equal to each other. As a result, when the upper and lower heads are combined, the center of the recording element and the center of the reproducing element coincide with each other vertically, and the center of recording and reproduction changes simultaneously with the movement of the actuator. In the above, ΔR
However, if the sign of ΔR is reversed, the absolute value of the value obtained by subtracting ΔR from the geometrical interval L0 is equal,
The sign may be reversed.

Based on the above examination, the linear recording density is 130 k.
The optimum arrangement of the recording element and the reproducing element under the BPI condition was obtained. The outermost circumference yaw angle is −20.5 degrees, the innermost circumference yaw angle is −2.4 degrees, and the gap between the magnetoresistive effect element and the magnetic pole end inside the gap on the outflow end side of the inductive element is 2.5 μm. In this case, if the height of the magnetoresistive effect element is set to 1.6 μm, Δ
When R is about 0.4 μm and the geometrical distance L0 between the recording element and the reproducing element is about 0.2 μm, the distance between the magnetic recording element and the reproducing element at the innermost circumference and the outermost circumference should be equal. I was able to. As a result, it is possible to minimize the decrease in the average data throughput due to the switching between the recording operation and the reproducing operation in the entire effective area on the medium.

The other head of the pair of heads on the upper and lower sides of the medium is set to have L0 of −0.9 μm, so that when the upper and lower heads are combined, the center of the magnetic recording element and the center of the reproducing element are vertically arranged. In agreement, the center of recording and reproduction could be changed simultaneously with the movement of the actuator.

[0020]

As described above, according to the present invention, it is possible to minimize the decrease in the data throughput due to the switching between the recording operation and the reproducing operation in the track.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a disk drive.

FIG. 2 shows the innermost and outermost positions of the head on the medium and the yaw angle.

FIG. 3 shows air bearing surface side shapes of a recording element and a reproducing element.

[Explanation of symbols]

10 ... Medium, 11 ... Center of rotation, 1
2 ... Actuator, 13 ... Rotation axis, 14 ...
Head slider, 21 ... innermost peripheral position, 22 ... outermost peripheral position, 31 ... reproducing element, 32 ... magnetic shield layer, 33 ... upper magnetic shield layer / lower magnetic pole, 34 ... recording element, 35 ... magnetic gap, 36 ... upper part Magnetic poles, 37 ... Electrodes.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hisayasu Honma 2880 Kozu, Odawara, Kanagawa Hitachi Storage Systems Division (72) Inventor Mio Suda 2880, Kozu, Odawara, Kanagawa Hitachi Storage Systems Business Department

Claims (6)

[Claims] 1. A recording / reproducing apparatus provided with a rotary medium, an actuator rotating about an axis, an element for recording information on the medium, and an element for reproducing information, and a recording element center on magnetic recording at the innermost part of the medium. And the value obtained by projecting the positional deviation amount of the reproducing element center in the radial direction of the medium and the value obtained by projecting the positional deviation amount of the recording element center and the reproducing element center on the magnetic recording in the outermost part of the medium in the radial direction of the medium. An information reading / writing device, characterized in that a recording element and a reproducing element are arranged in the. 2. A yaw angle at the innermost part of the medium and a yaw angle at the outermost part of the medium when a yaw angle is defined by a straight line connecting the rotation axis of the actuator and the recording element and a tangent line of the medium movement direction in the recording element part. Let θ1 and θ2 respectively be the distance between the geometrical centers of the recording element and the reproducing element in the direction of the straight line connecting the axis of the actuator and the recording element, and let L0 be the linear direction connecting the axis of the actuator and the recording element. The value of (L ₀ + ΔR) cos θ1−bsin θ1 where b is the magnetic recording distance between the recording element and the reproducing element and ΔR is the distance between the geometric center of the reproducing element and the magnetic recording center. And bsin
The values of θ 2 − (L ₀ + ΔR) cos θ 2 are substantially equal, or the values of (L ₀ −ΔR) cos θ 1 −bsin θ 1 and bsin θ ₂ − (L ₀ −
An information reading / writing device characterized in that the values of ΔR) cos θ2 are substantially equal. 3. A set of magnetic heads including a corresponding recording element and reproducing element sandwiching a medium, wherein (L ₀ + ΔR) in the value of each part of either head described above.
Of the other head and the value of (L ₀ + ΔR) of the other head are substantially equal and opposite in sign, or (L ₀ − of one head).
[Delta] R) of the value and the other head (L ₀ - [Delta] R) value generally equal and code information reading and writing apparatus of claim 2, wherein the opposite. 4. A head, wherein the reproducing element comprises a magnetoresistive effect element and a magnetic shield layer sandwiching the magnetoresistive effect element, and the recording element comprises an inductive type element having a gap on a medium resistance surface, further comprising an axis of the actuator. Magnetic recording distance b between the recording element and the reproducing element in the linear direction connecting the recording elements b
The information reading / writing apparatus according to claim 2 or 3, wherein is a distance between the magnetoresistive effect element and the magnetic pole end inside the gap on the outflow end side of the inductive element. 5. The reproducing element comprises a magnetoresistive effect element and a magnetic shield layer sandwiching the magnetoresistive effect element, and a distance ΔR between a geometric center of the reproducing element and a magnetic recording center in the track width direction.
5. The information reading / writing apparatus according to claim 4, wherein is about 1/4 of the width of the magnetoresistive effect element in the signal magnetic field penetration direction. 6. The width of the reproducing element in the signal magnetic field penetration direction is 2
The information reading / writing apparatus according to claim 5, wherein the information reading / writing apparatus has a thickness of less than μm.