JP3752271B2 - Magnetic head and magnetic disk device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a magnetic head applied to a magnetic disk device, and more particularly to a head structure optimal for realizing a high track density of a magnetic disk device.
[0002]
[Prior art]
At present, a magnetic head applied to a magnetic disk device is generally formed on a member called a slider, and the magnetic disk device utilizes a servo information recorded on the magnetic disk and uses a magnetic head formed on the slider. Controls positioning on any magnetic disk.
[0003]
Some of the magnetic heads used as described above have been miniaturized and formed of thin films. There are roughly two types of magnetic heads formed of a thin film, and there are a magnetic head composed of a recording / reproducing element and a composite magnetic head in which a recording element and a reproducing element are independently formed. These thin film magnetic heads are usually formed on a slider body serving as a base material.
[0004]
The slider on which the magnetic head is mounted is fixed to an actuator provided in the magnetic disk device, and is positioned at an arbitrary position on the magnetic disk by controlling the actuator. Various proposals have been made on high-precision positioning technology for magnetic heads. Journal of Japan Society of Applied Magnetics, Vol. 18 No. 4 (1944), p. 867, FIG. 11 shows a structure in which the recording / reproducing combined element finely moves with respect to the slider. This paper focuses on improving the track density of a magnetic disk in order to increase the recording density. 11, a piezo element is incorporated in the central portion of the magnetic head slider so that the head element provided at the rear ends of the floating rail portions on both sides can be slightly changed.
[0005]
[Problems to be solved by the invention]
In the above document, the longitudinal direction of the magnetic head slider and the longitudinal direction of the suspension for fixing the magnetic head slider are fixed differently by 90 °. Also, it is not disclosed what actuator the magnetic head arm that holds the suspension is driven by. In these cases, the actuator for driving the magnetic head arm can be a linear type or a rotary type.
[0006]
The linear type actuator performs a positioning operation parallel to the radial direction of the magnetic disk. The linear actuator described in FIG. When the 11 magnetic head slider is positioned on the magnetic disk, the recording element and the reproducing element of the separation type magnetic head in which the recording element and the reproducing element are separated are positioned on different tracks with respect to the target track. Almost no. However, FIG. When the 11 magnetic head slider is positioned on the magnetic disk, the recording element and the reproducing element of the separation type magnetic head may not be positioned on the target track due to the mechanism.
[0007]
Therefore, in particular, in a magnetic disk apparatus having an inline type rotary actuator in which the longitudinal direction of the magnetic head slider and the longitudinal direction of the magnetic head arm for fixing the magnetic head slider coincide with each other, the recording element and the reproducing element of the separation type magnetic head are provided. It is presumed that no consideration is given to the problem that the target is not positioned on the rack.
[0008]
Let us consider this issue in more detail. When a thin film magnetic head, particularly a composite thin film magnetic head in which a recording element and a reproducing element are independently formed, is positioned by an inline type rotary actuator, the radial position of the recording element and the reproducing element on the magnetic disk is very small. May be misaligned. Normally, a composite thin film magnetic head is formed so that the center of the recording element and the center of the reproducing element coincide with each other. However, when achieving a high track density, the difference in the disk radial position between the recording element and the reproducing element is a problem. Become.
[0009]
Also, when positioning is performed using servo information read using the reproducing element, if there is a disc radius position difference between the recording element and the reproducing element, the recording element will not enter adjacent tracks. In addition, the track width must be increased to some extent, and the difference in the disk radial position between the recording element and the reproducing element becomes a serious problem for increasing the track density.
[0010]
An object of the present invention is to provide a magnetic head in which a recording / reproducing element-separated type magnetic head can be positioned on a track with high accuracy as the track density increases.
[0011]
A further object of the present invention is to provide a magnetic disk device having a magnetic head slider capable of highly accurate track positioning in a magnetic disk device having a rotary actuator.
[0012]
[Means for Solving the Problems]
A recording element and a reproducing element are provided in the vertical direction with respect to the magnetic head slider as a base material, and there is a separation surface between the upper element and the lower element so that the upper element and the lower element can move relative to each other. The upper element is fixed so that the relative position of the element can be changed. In order to change the relative position of the upper element to the lower element, there is provided means for moving the upper element in parallel with the surface of the substrate, and the radius of the recording element and the reproducing element on the magnetic disk regardless of the position of the element on the magnetic disk. The relative position is determined so that the positions are substantially the same.
[0013]
Furthermore, the magnetic head has sensing means for detecting that the upper element has moved, and this sensing means is for positioning the upper element at a radial position substantially equal to the radial position of the magnetic disk on which the lower element is positioned. Outputs information necessary for.
[0014]
Since the recording element and the reproducing element can be positioned at the same radius of the magnetic disk, the width of the recording element and the reproducing element can be made the same, and the track width can also be reduced because the recording element does not enter the adjacent track.
[0015]
The present invention is also applied to a magnetic disk device that records / reproduces information at a target position of a magnetic disk by a magnetic head, and is a magnetic head slider provided with a magnetic head, and a slider base constituting the main part thereof. A magnetic head provided with elements for recording and reproduction on the top and bottom is formed on the material, and the magnetic head has a separation surface for independently forming the upper element and the lower element, and the upper element is formed on the surface of the substrate. A magnetic head slider having a moving means for moving in parallel with the magnetic head, a magnetic head arm for holding the magnetic head slider, and driving the magnetic head arm around the rotation axis to position the magnetic head at a desired position on the magnetic disk And an actuator.
[0016]
Further, the magnetic disk apparatus to which the present invention is applied recognizes the radial position of the magnetic head on the magnetic disk from the rotational drive state of the actuator and / or the position information read by the magnetic head, and the recognized radius. Control means for controlling the moving means for moving the upper element of the magnetic head according to the position is provided.
[0017]
Further, the magnetic disk apparatus to which the present invention is applied has sensing means for detecting that the upper element of the magnetic head slider has moved, and the control means controls the moving means for moving the upper element by the output from the sensing means. To do.
[0018]
Furthermore, in the magnetic disk apparatus to which the present invention is applied, the upper element of the magnetic head is moved in parallel with the base surface of the magnetic head slider in accordance with the radial position of the magnetic disk.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0020]
1 is a perspective view of a slider 1 showing an embodiment of the present invention, FIG. 2 is a detailed plan view of a portion A of FIG. 1, and FIG. 3 is a detailed plan view of a portion B of FIG.
[0021]
A recording element 3 and a reproducing element 4 are provided in the vicinity of the outflow end 2 of the slider 1. A gap 5 is provided between the recording element 3 and the reproducing element 4. The recording element 3 is an inductive thin film head having a lower core 6 and an upper core 7, and a substantial element width is determined by the width of the upper core 7. The recording element 3 is formed on a movable portion 9 driven by a comb-shaped electrostatically driven fine movement actuator 8, and the movable portion 9 is supported by a beam 10 coupled to the slider 1. When the movable portion 9 is moved left and right by the actuator 8, the beam 10 is bent left and right, and the recording element 3 is also moved left and right. The beam 10 is provided with a strain gauge 11, and the relative displacement between the recording element 3 and the reproducing element 4 can be detected from the output signal.
[0022]
When the movable portion 9 of the fine movement actuator 8 that performs comb-teeth electrostatic drive is electrically dropped to the ground and a voltage is applied to the fixed portion 12, the movable portion 9 is attracted to the fixed portion 12 by electrostatic force. In FIG. 1, when the recording element 3 is to be moved to the right side, a voltage is applied to the right fixed portion 12a, and when it is desired to be moved to the left side, a voltage is applied to the left fixed portion 12b.
[0023]
As another method of moving the movable portion 9 left and right using the fine movement actuator 8 of the comb-teeth electrostatic drive, a fixed bias voltage is applied to the movable portion 9 and the two fixed portions 12a and 12b are applied. In addition, an offset voltage with respect to the bias voltage may be applied simultaneously and in phase. In this case, twice the acceleration can be obtained with the same voltage as described above.
[0024]
FIG. 4 shows an example of a block diagram of positioning control. The reproducing element 4 is positioned in the same manner as a normal magnetic disk device. That is, the normal positioning process of the magnetic disk device is to detect a positioning signal stored in the magnetic disk using a reproducing element for reproducing data and use it for the positioning process. Specifically, the position difference of the reproducing element 4 with respect to the target position is input to the reproducing element positioning controller 15 from the position information 14 and the target position information 13 of the reproducing element 4. The output of the reproducing element positioning controller 15 is input to the reproducing element driving actuator 16, and the reproducing element 4 is positioned.
[0025]
The position information 14 of the reproducing element 4 is fed back to the input side of the reproducing element positioning controller 15 by the position detector 17 of the reproducing element 4. The position detector 17 of the reproducing element 4 detects a positioning signal written in advance on the magnetic disk by the reproducing element 4 and converts it into the same dimension as the target position information 13.
[0026]
The positioning of the recording element 3 with respect to the reproducing element 4 is determined based on the difference between the position information 14 of the reproducing element 4 and the target position obtained from the target position information 13 and the position of the reproducing element 4. The position 20 of the recording element 3 with respect to the reproducing element 4 is subtracted from the output of the simulator 18 to be generated and the sum of the target position 19 of the recording element 3 with respect to the predetermined reproducing element 4 corresponding to the target position 13. The signal is input to the fine actuator controller 21 and the output signal is input to the fine actuator 8 to position the recording element 3.
[0027]
The position of the recording element 3 with respect to the reproducing element 4 is fed back to the input side of the controller 21 for the fine movement actuator 8 by a detector such as a strain gauge 11. The simulator 18 may be similar to a simulator for a course actuator of a general optical disk apparatus. Further, a predetermined target position 19 of the recording element 3 with respect to the reproducing element 4, that is, a deviation amount of the recording element 3 with respect to the reproducing element 4 corresponding to the radial position of the magnetic disk is determined from the reference table prepared in advance. What is necessary is just to output according to the information 13. FIG.
[0028]
As described above, in the present embodiment, when recording is performed on the magnetic disk device, the recording element 3 is positioned at a target position on the same radius as the reproducing element 4 by the fine movement actuator 8.
[0029]
In a configuration without the strain gauge 11, positioning control can be performed by open loop control using a voltage applied to the fine movement actuator 8.
[0030]
As the fine movement actuator 8, the same effect as in this embodiment can be obtained by using a piezoelectric actuator in addition to the comb-shaped electrostatic drive actuator. Further, the same effect can be obtained if the beam 10 is constituted by a bimorph type piezoelectric actuator instead of the fine movement actuator 8.
[0031]
When the beam 10 is composed of a bimorph piezoelectric actuator, a configuration similar to that of the comb-shaped electrostatic drive actuator is used as a capacitive sensor, and the recording element 3 is replaced with the strain gauge 11. The relative displacement of the reproducing element 4 can also be observed.
[0032]
Another embodiment of the present invention will be described with reference to the drawings.
[0033]
FIG. 5 is a perspective view of a slider showing another embodiment of the present invention. Bimorph type piezoelectric actuators 23 are provided on both sides of the slider body 22 with the slider body 22 and the side clearance 24 sandwiched therebetween, and are connected to the slider body 22 in the vicinity of the inflow end 25. The two bimorph piezoelectric actuators 23 are connected to the support beam 26 on the outflow end 2 side. A minute gap 5 of about several microns is provided between the support beam 26 and the slider body 22. The reproducing element 4 is provided in the vicinity of the outflow end 2 of the slider body 22, and the recording element 3 is provided at a position facing the reproducing element 4 of the support beam 26. The two bimorph piezoelectric actuators 23 are provided with strain gauges 11.
[0034]
When a voltage is applied to the two bimorph piezoelectric actuators 23, the outflow end 2 moves left and right with the inflow end 25 as a fulcrum. By this operation, the recording element 3 provided on the support beam 26 is also positioned left and right. As the bimorph type piezoelectric actuator 23, for example, a P-7 type piezoelectric element manufactured by Murata Manufacturing Co., Ltd. can be used. If the length is 1 mm, the width is 300 microns, the thickness is 20 microns, and the sum of the mounting lengths of the slider body 22 and the support beam 26 is 200 microns, the displacement of plus or minus 3 microns is applied with an applied voltage of plus or minus 3V. Obtainable.
[0035]
As in the previous embodiment, when recording is performed on the magnetic disk device, the recording element 3 is positioned on the same radius of the reproducing element 4 and the magnetic disk by the two bimorph piezoelectric actuators 23. Positioning control is performed by feedback control using a signal from the strain gauge 11. In the configuration without the strain gauge 11, positioning control can be performed by open loop control using voltages applied to the two bimorph piezoelectric actuators 23.
[0036]
Instead of being driven by the bimorph piezoelectric actuator 23, a parallel plate type electrostatic actuator having two bimorph piezoelectric actuators 23 and opposing portions of the slider body 22 as electrodes may be configured and driven. There is an effect.
[0037]
In the case of driving with the bimorph type piezoelectric actuator 23, the same effect can be obtained by detecting and using the capacitance of the side clearance 24 instead of the output signal of the strain gauge 11.
[0038]
In the above embodiment, the reproducing element 4 is fixed to the slider 1 and the recording element 3 is finely moved. However, the order of the recording element 3 and the reproducing element 4 in the longitudinal direction of the slider 1 is reversed, and the recording element 3 is moved to the slider 1. The same effect can be obtained by slightly moving the reproducing element 4 and fixing the recording element 3 and the reproducing element 4 on the same radius of the magnetic disk. Further, when the reproducing element 4 is finely moved, it can be used for minute positioning at the time of reproduction, and there is an effect that the positioning accuracy can be improved.
[0039]
【The invention's effect】
According to the present invention, since the recording element and the reproducing element are positioned at the same radial position regardless of the radial position of the element on the magnetic disk disk, the width of the recording element and the reproducing element can be made the same, and the track width can be reduced. Therefore, a magnetic head for a magnetic disk device having a high track density can be realized.
[Brief description of the drawings]
FIG. 1 is a perspective view of a magnetic head slider to which the present invention is applied.
2 is a detailed plan view of part A of FIG.
3 is a detailed plan view of a portion B in FIG.
FIG. 4 is a block diagram of positioning control according to the present invention.
FIG. 5 is a perspective view of a slider according to another embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Slider 2 ... Outflow end 3 ... Recording element 4 ... Reproducing element 5 ... Clearance 6 ... Lower core 7 ... Upper core 8 ... Fine movement actuator 9 ... Movable part 10 ... Beam 11 ... Strain gauge 12 ... Fixed part 13 ... Target position information 14 ... Reading element position information 15 ... Reading element positioning controller 16 ... Reading element driving actuator 17 ... Reading element position detector 18 ... Simulator 19 ... Recording element relative to the reproducing element Predetermined target position 20 ... position 21 of recording element relative to reproducing element ... controller 22 for fine movement actuator ... slider body 23 ... bimorph type piezoelectric actuator 24 ... side clearance 25 ... inlet end 26 ... support beam

Claims (6)

In an information recording / reproducing apparatus having an information recording medium ,
A first element mounted on the same slider for reproducing or recording information on the information recording medium, and a second element disposed in the longitudinal direction of the slider with respect to the first element;
Based on the position information of the first element of the information recording medium and the position information of the second element with respect to the first element, the position of the second element with respect to the first element is controlled , An information recording / reproducing apparatus comprising: a control unit configured to adjust a radial position of the first element and a radial position of the second element in an information recording medium . In an information recording / reproducing apparatus having an information recording medium ,
A first element mounted on the same slider for reproducing or recording information on the information recording medium, and a second element disposed in the longitudinal direction of the slider with respect to the first element;
A first detector for detecting first position information which is position information of the first element in the information recording medium;
A second detector for detecting second position information which is position information of the second element with respect to the first element;
The position of the second element with respect to the first element is controlled based on the first position information and the second position information, and the radial position of the first element and the second position on the information recording medium are controlled . An information recording / reproducing apparatus comprising an actuator that adjusts the radial position of the element to coincide with each other . A first element that records or reproduces information in an information recording medium and is mounted on the same slider; and a second element that is disposed in the longitudinal direction of the slider with respect to the first element;
A detector for detecting position information of the second element relative to the first element;
Based on position information of the first element in the recording medium and position information of the second element with respect to the first element detected by the detector, the first element of the second element An information recording / reproducing head comprising: an actuator for controlling the position of the first element and the radial position of the second element in the information recording medium so as to coincide with each other . Mounted on an information recording / reproducing apparatus having an information recording medium to record or reproduce information on the recording medium, a first element mounted on the same slider and a slider with respect to the first element In the control method for controlling the position of the second element arranged in the longitudinal direction ,
Detecting position information of the first element in the information recording medium;
Detecting position information of the second element relative to the first element;
Based on the position information of the first element in the information recording medium and the position information of the second element with respect to the first element, the position of the second element with respect to the first element is controlled , A control method comprising adjusting the radial position of the first element and the radial position of the second element in an information recording medium . In an information recording / reproducing apparatus having an information recording medium ,
A first element and a second element for reproducing or recording information on the information recording medium;
A slider having the first element and the second element disposed in a longitudinal direction of the slider with respect to the first element ;
Control the position relative to the first element of the first of the second element based on the position information of the second element position information for the first element of the element in the information recording medium, the information A control unit that adjusts the radial position of the first element and the radial position of the second element in the recording medium to coincide with each other;
The information recording / reproducing apparatus according to claim 1, wherein the control unit is formed on the slider. In an information recording / reproducing apparatus having an information recording medium ,
A reproducing element that reproduces information on the information recording medium, and a recording element that is mounted on the same slider as the reproducing element and is disposed in the longitudinal direction of the slider with respect to the reproducing element ;
Based on the position information of the reproducing element and the position information of the recording element with respect to the reproducing element, the position of the recording element with respect to the reproducing element is controlled , and the radial position of the first element and the first position on the information recording medium are controlled . An information recording / reproducing apparatus comprising a control unit that adjusts the radial positions of the two elements to coincide with each other .

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