JP2001291218A - Inspection device of magnetic head slider, magnetic disk for inspection and magnetic disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inspection device for discriminating whether a magnetic head slider is accepted or not before being mounted on a magnetic disk device by taking the contact between a magnetic head slider and the disk into consideration. SOLUTION: This inspection device of magnetic head slider inspects the magnetic head slider by using a read/write tester which is furnished with the magnetic disk, a rotating mechanism to rotate the magnetic disk, a mounting part of magnetic head slider, a positioning mechanism of magnetic head slider, a reading/writing circuit for a read/write signal, and a control part for controlling the operation of the whole device, then the decision is made whether the magnetic head slider is accepted or not in such a manner that the floating amount of the magnetic head slider is successively reduced and the changing amount of the time interval between read out signals of the signal written into the magnetic disk in the circumferential direction of the magnetic disk is measured every time the floating amount is reduced, then the changing amount of the time interval is compared with the allowable value of the time interval changing amount to detect that the reduction of the floating amount is repeated by specific times.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk drive, and more particularly, to a magnetic disk drive for inspecting a contact state between a magnetic head slider mounted on the magnetic disk drive and a magnetic disk. The present invention also relates to a magnetic head slider inspection device capable of guaranteeing the reliability of the device, and a highly reliable magnetic disk device equipped with the magnetic head slider selected by the inspection device.

[0002]

2. Description of the Related Art In a magnetic disk drive, the distance between a magnetic head slider and a magnetic disk has been reduced in order to realize a high recording density. As a result, the risk of a destructive sliding accident due to the contact between the magnetic head slider and the magnetic disk is increasing. In order to ensure the reliability of the magnetic disk, it is necessary to guarantee the flying height of the magnetic head slider.

[0003] From such a viewpoint, a conventional inspection apparatus and an inspection method for selecting a magnetic head slider before mounting on a magnetic disk apparatus include a method of using a glass disk for inspection, and using a glass disk and a magnetic head slider. When a magnetic head slider assembly to be inspected is set using a flying height measuring device having a flying height detection mechanism that detects a floating clearance by interference fringe detection using white light or interference light intensity, the magnetic head slider assembly is lifted above a glass disk. This has been done by examining the flying characteristics.

[0004] The concept of reliability design of a magnetic disk drive that has been conducted so far is to raise the height of a magnetic head slider floating above a glass disk from the standpoint of securing an actual clearance between the magnetic head slider and the magnetic disk. A design has been made to make the flying margin calculated in consideration of the surface roughness of the magnetic disk in the characteristics plus.

As a method of detecting the contact between the magnetic head slider and the magnetic disk for accurately calculating the positive margin, a method of analyzing the frequency of a read signal as disclosed in Japanese Patent Application Laid-Open No. 5-325461 is known. However, while the spectrum output of only the fundamental wave is detected during non-contact, the suspension is shaken in the circumferential direction during contact, so that in addition to the fundamental wave spectrum, the sideband spectrum of the vibration in the bending direction of the suspension is generated. There is technology used.

[0006]

In recent years, there has been a demand for a further decrease in flying height in order to achieve a high recording density.
Since the contact between the magnetic head slider and the magnetic disk cannot be avoided anymore, research and development have also been conducted on a magnetic disk device in consideration of the contact between the head and the disk. In a magnetic disk device considering such contact, for example, the magnitude of frictional force at the time of contact directly affects the life of the device. At this stage, it is necessary to select the magnetic head slider by some method.

Further, even if the contact is at a level that does not cause a problem in terms of the proof stress of the head disk, the time interval between the written signals fluctuates (jitter) due to the vibration of the slider at the time of the contact. If a certain jitter exceeds a certain level, read / write becomes impossible.

In the conventional magnetic disk drive,
The reliability of the magnetic disk drive has been ensured by selecting the magnetic head slider according to the flying height of the flying height measurement device.However, in the future magnetic disk device considering contact, for example, the frictional force generated by the contact is measured and the magnetic It is extremely important to select head sliders and mount them on the apparatus in order to ensure reliability.

In addition to directly measuring the frictional force generated by the contact, the magnitude of the slider vibration at the time of the contact and the circumferential fluctuation amount (jitter amount) of the read signal caused by the vibration of the magnetic head slider. It is important to select a magnetic head slider according to the size of the magnetic head slider, and an inspection apparatus and an inspection method for this purpose are indispensable development issues in selecting a low flying magnetic head slider in the future.

An object of the present invention is to replace a conventional flying measurement device in a magnetic disk device in which the flying height of a magnetic head slider is reduced and head-disk contact occurs to ensure the reliability of the device. An inspection device for selecting a head slider according to the magnitude of a frictional force at the time of contact, a slider vibration amount generated by the contact, or a circumferential variation amount (jitter amount) of a read signal caused by the slider vibration; and By developing an inspection method using the device and mounting the magnetic head slider selected according to the present invention on the device, sufficient reliability can be obtained even when contact between the magnetic head slider and the magnetic disk occurs. An object of the present invention is to provide a secured magnetic disk device.

[0011]

In order to solve the above problems, the present invention mainly employs the following configuration.

A magnetic disk, a rotating mechanism for rotating the magnetic disk, a magnetic head slider mounting section, a magnetic head slider positioning mechanism, a read / write circuit for read / write signals, a control section for controlling the operation of the entire apparatus, A magnetic head slider inspection apparatus for inspecting a magnetic head slider using a read / write tester provided with a magnetic head slider, wherein the flying height of the magnetic head slider is sequentially reduced, and the magnetic head slider is written on a magnetic disk every time the flying height decreases. The time interval variation in the magnetic disk circumferential direction between the read signals of the read signals is measured, the time interval variation is compared with a time interval variation allowable value, and it is detected that the flying height reduction has been repeated a specified number of times. Magnetic head slider inspection apparatus for determining whether a magnetic head slider is acceptable or not.

Also provided are a rotating mechanism for rotating the magnetic disk, a magnetic head slider mounting section, a magnetic head slider positioning mechanism, a read / write circuit for read / write signals, and a control section for controlling the operation of the entire apparatus. A magnetic head slider inspection apparatus for inspecting a magnetic head slider using a read / write tester, wherein a parameter indicating the surface roughness of the magnetic disk is expressed by a projection height Rp. Can be inspected even in a contact state with a part of the protrusion height, the protrusion height is uniform on the same circumference of the magnetic disk, and the protrusion height is stepwise or continuously from the inner circumference to the outer circumference. Inspection magnetic disk changed.

When the gap between the rotating glass disk and the transducer position of the magnetic head slider is defined as the flying height, the defined flying height is 6 nm or less at normal temperature (20 ° C.) and normal pressure (atmospheric pressure). A magnetic disk drive equipped with a magnetic head slider in which a gap between a conversion element of the magnetic head slider and a magnetic film of the magnetic disk is 10 nm or less when the magnetic head slider is present or on a rotating magnetic disk. When reading a signal written under the condition of the lowest flying height within the range of environmental conditions described in the specifications of the magnetic disk device, reading the signal written to the magnetic disk The time interval variation in the magnetic disk circumferential direction between signals is
A magnetic disk drive which is 0.1% or less of a time interval of a written signal.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the outline of the present invention and its functions and operations will be described. In the present invention, before mounting on a magnetic disk drive, a specific parameter indicating a contact state at the time of mounting the drive is fixed. A magnetic head slider inspection magnetic disk, a magnetic disk for inspecting a magnetic head slider, a rotating mechanism for rotating the disk, a magnetic head slider mounting portion, a magnetic head slider positioning mechanism, a write signal writing circuit,
It is composed of a read signal reading circuit, a controller, a contact state detector, and the like.

The flying height of the magnetic head slider fluctuates depending on the environmental conditions in which the magnetic disk device is used, for example, temperature and atmospheric pressure. Therefore, even with a magnetic head slider that does not contact the magnetic disk under normal temperature and normal pressure conditions, contact with the magnetic disk can occur due to changes in environmental conditions. For magnetic head sliders where light contact occurs under normal temperature and normal pressure conditions, the contact becomes stronger, so the flying height is changed to indicate the contact state with respect to the predetermined floating amount under normal temperature and normal pressure conditions. You need to look at certain parameters.

Therefore, as a method of changing the contact state with the magnetic disk by raising and lowering the flying height of the magnetic head slider, a method of changing the rotation speed of the spindle,
A method of changing the atmospheric pressure using a closed chamber, or using a disk in which the surface roughness of the magnetic disk for magnetic head slider inspection to be used, in particular, in this case, the projection height Rp has regions different in the radial direction. It is effective to change the contact position by changing the flying position of the magnetic head slider.

As a parameter indicating the contact state and the contact state detector, a frictional force and a frictional force detector, a laser Doppler / velocimeter (LDV) for measuring a slider variation and a slider variation, and the like can be considered. When selecting a slider, a read / write tester is always used to inspect the read / write characteristics of the head. Therefore, a method of detecting a contact state by utilizing or extending the function of the read / write tester is most effective. Means. Techniques for using or expanding this read / write tester include:
Using an interval analyzer as a contact state detector, measure the signal-to-signal interval when reading a written signal, and use the distribution of this signal interval as a parameter to indicate the contact state between the slider and the disk. It is.

Next, an inspection apparatus and an inspection method for a magnetic head slider according to an embodiment of the present invention will be specifically described with reference to the drawings. FIG. 1 is a configuration diagram of a magnetic head slider inspection apparatus using a read / write tester according to a first embodiment of the present invention. Magnetic head slider inspection apparatus 10 using read / write tester shown in FIG.
Are a spindle 1, a carriage 2, a magnetic head slider mounting part 3, a magnetic head slider 4, an inspection disk a
5. Drive circuit 2 for moving spindle 1 and carriage 2
0, a read / write RW circuit 30, an interval analyzer 40, a controller 50 for controlling the entire apparatus, and an analyzer 60 for analyzing the acquired data. Here, in the entire configuration of FIG. 1, the configuration excluding some functions of the interval analyzer 40 and the analysis unit and some functions of the control unit is the same as the configuration of a read / write tester conventionally used for inspection of recording / reproduction characteristics. It is.

The inspection apparatus of the present invention is characterized in that it has a function of controlling the contact strength by changing the flying height of the slider, and analyzing the amount of change in the time interval between the signals when the signals are read. It is in. As a method of changing the flying height of the slider, there are a method of changing the rotation speed of the spindle and a method of changing the pressure of the atmosphere in which the magnetic disk device is used. In the embodiment of FIG. Is used to control the contact strength. The read / write tester itself is originally used for inspecting the recording / reproducing characteristics of the magnetic disk drive, and the read / write tester is used or expanded to use the read / write tester in the magnetic head slide inspection apparatus. Used in addition to

FIG. 2 shows an example of an inspection procedure performed using the inspection apparatus using the read / write tester shown in FIG. The details will be described below. Rotation speed N in step 1
0, a signal is written to the disk at the write frequency W0. In step 2, the time interval (circumferential fluctuation component) Δt of the read signal at this time is measured (Δt at this time is taken as Δt0). Erase (erase) write signal in step 3
I do. In step 4, the number of rotations is reduced to N = N1. In step 5, a signal is written again at the write frequency W0. At step 6, the time interval (circumferential fluctuation component) Δt of the read signal at this time is measured (at this time, Δt is taken as Δt1). The time interval (circumferential fluctuation component) Δt of the read signal defined here will be described first with reference to FIG.

FIG. 3 shows an example of a captured lead signal measured to determine the contact strength. This data is the rotation speed N
0, a signal written at a frequency W0 is fetched through an interval analyzer 40 for a certain period of time, and expresses the relationship between the time interval between signals and the frequency of occurrence thereof during that time. Therefore, the time interval between the distribution peak positions is 1 / W0, which is the reciprocal of the frequency of the write signal. The solid line (a) in FIG. 3 shows the result obtained when the magnetic head slider is completely flying without contacting the magnetic disk. The reason why the distribution is broad even in the non-contact state is due to the influence of the rotation fluctuation of the spindle 1.

When the flying speed is lowered by changing the rotation speed and the contact occurs, the slider receives a force in the circumferential direction of the disk. Therefore, when reading the written signal, the slider is caused not only by the rotation fluctuation of the spindle but also by the contact. With the addition of the component, the peak value of the occurrence frequency is reduced and the distribution is indicated by a dotted line (b) in FIG.
It becomes broader like. Therefore, by measuring the time interval Δt when the peak value of the occurrence frequency is halved and examining the change in Δt when the levitation is lowered, it is possible to grasp the influence of the contact.

The time interval between the signals in the case of FIG. 3 is a time interval corresponding to one cycle of the read signal waveform. However, when an adjacent signal written for an appropriate cycle with a gap is read. The time interval between adjacent signals may be used.

Returning to FIG. 2, the flow will be described. In steps 7 and 8, it is checked whether or not i (the number of times the rotational speed is reduced) is greater than a preset number of times M. If i is less than M times, Δti and an allowable time interval (jitter tolerance) are used. Value) Δtp and discriminate. Here, if Δti is smaller, i = i + 1 is set, the constant rotation speed is reduced, and Δti is measured. This operation is repeated, and when Δti> Δtp when i is equal to or less than the predetermined M, this magnetic head slider is handled as a rejected product. If it passes, the process proceeds to the next step, for example, the inspection of the read / write characteristics of the head. In other words, the rotational speed is sequentially reduced, and in each case, Δti <Δtp
Is passed if the specified number of times M can be repeated while confirming the above.

At this time, Δtp and M used here are parameters for performing selection in view of the contact strength of the slider, and Δtp is 0.2 (0 .0) to 1 / W0 which is the reciprocal of the frequency of the write signal. 1 × 2)% (Δtp is 0.1% of (1 / W0) is doubled), and Δt0 is multiplied by a certain constant.
This is practical in consideration of rotation fluctuation of a spindle used in an inspection device and a single difference of a magnetic head. In other words, it is appropriate that the amount of change in the time interval between the read signal and the signal is 0.1% of the time interval between the written signals as the pass / fail decision criterion.

In view of the above, in a magnetic disk drive equipped with a magnetic head slider that is actually operating, a narrow gap such that the gap between the conversion element of the magnetic head slider and the magnetic film of the magnetic disk is 10 nm or less. In a situation where there is a possibility that the slider and the disk may come into contact with each other, when reading a signal written under the condition that the flying height is the lowest within the range of the environmental conditions described in the specifications of the magnetic disk device, A magnetic head slider whose time interval variation in the circumferential direction of the magnetic disk between read signals of the signals written on the magnetic disk is 0.1% or less of the time interval of the written signals is accepted. It is.

The inspection disk used in this inspection apparatus will be described below. FIG. 4 shows the characteristics of an inspection disk a used in a head slider inspection device using a read / write tester according to an embodiment of the present invention, and the characteristics of an actual disk and an inspection disk b actually mounted on a magnetic disk device for comparison. FIG. In FIG. 4, when the same magnetic head slider is floated above the real disk, the test disk a, and the test disk b, when the number of revolutions is lowered to reduce the flying height, the real disk contacts at the speed V0. Starts, and the slider circumferential fluctuation gradually increases, and the contact starts at the peripheral speed V1 on the test disk a, and the slider circumferential fluctuation rises slightly large, and the contact occurs at the peripheral speed V2 on the test disk b. The beginning indicates that the slider circumferential fluctuation rapidly rises.

The characteristics of the disk used in the inspection device are that when combined with a magnetic head slider mounted on an actual magnetic disk device, the frictional force of the slider is greater than when the disk is brought into contact with the actual disk used in the actual magnetic disk device. Is used as an inspection disk so as to increase the value, that is, to have a high sensitivity when the flying height is lowered. However, it is necessary to keep in mind that the use of such a highly sensitive inspection disk b causes disadvantages such as a large measurement variation and, in some cases, damage to the magnetic head slider.

Further, the magnetic disk used in the present inspection apparatus is considered to basically come into contact with the magnetic head slider at the time of inspection and its surface state changes, so that a master disk for inspecting the inspection disk in advance is used. It is necessary to prepare a magnetic head slider, replace the inspection disk after inspection of a certain number of magnetic head sliders, and check the state of the disk with the master magnetic head slider.

Therefore, in an actual magnetic disk drive, when an allowable circumferential time interval (allowable jitter value) at the time of occurrence of contact is Δtd, a magnetic head slider mounted on this device is used for inspection for selecting. When the inspection disk a is used as the disk, a disk having a time interval in the circumferential direction (allowable jitter value) smaller than Δtp is regarded as a passable disk.

FIG. 5 is a configuration diagram of a magnetic head slider inspection apparatus using or expanding a read / write tester according to a second embodiment of the present invention. 1, a spindle 1, a carriage 2, a magnetic head slider mounting portion 3, a magnetic head slider 4, an inspection disk a5, a drive circuit 20 for moving the spindle 1 and the carriage 2, and a lead shown in the first embodiment shown in FIG. RW circuit 30 for writing, interval analyzer 40, control unit 5 for controlling the entire apparatus
0, the analysis unit 60 that analyzes the captured data
The pressure reducing tank 70 and the pressure pump 80 are added. In the embodiment of FIG. 5, the contact strength was controlled by reducing the pressure of the atmosphere.

FIG. 6 shows an example of an inspection procedure performed using the inspection apparatus using the read / write tester shown in FIG. The details will be described below. In step 1, a signal is written to the disk at the rotation speed N0 and the write frequency W0. In step 2, the circumferential component Δt of the read signal at this time is measured (Δt = Δt0). In step 3, the atmospheric pressure is reduced by a certain amount to P = P1. In step 4, the circumferential component Δt of the read signal at the pressure P1 is measured (Δt = Δt)
1).

In steps 5 and 6, it is checked whether or not i is greater than a preset number M. If i is less than M times, Δti and an allowable time interval (tolerable jitter value)
A comparison with Δtp is performed for discrimination. Here, if Δti is smaller, i = i + 1 is set, the constant pressure is reduced, and Δti is measured. This operation is repeated, and when Δti> Δtp when i is equal to or less than the predetermined M, this magnetic head slider is handled as a rejected product. If it passes, the process proceeds to the next step, for example, the inspection of the read / write characteristics of the head.

At this time, Δtp and M used here are parameters for performing selection from the viewpoint of the contact strength of the slider, and Δtp is 0.2 (0 .0) to 1 / W0 which is the reciprocal of the frequency of the write signal. 1 × 2) The value calculated by multiplying Δt0 by a certain constant with reference to the value multiplied by% is
This is practical in consideration of the rotation fluctuation of the spindle used in the inspection device and the difference of the magnetic head alone.

Although a pressure reduction method is employed in FIG. 6 for pressure adjustment, a method of controlling the flying height by applying pressure may be used, and this is also within the scope of the present invention and does not deviate.

Next, as a method of determining the contact strength,
In addition to measuring the amount of fluctuation in the circumferential direction (the amount of jitter), measurement of the amount of deviation in the track direction (off-track amount) is also effective. This is because even when the angle between the magnetic head slider and the rotation direction of the disk is almost 0 degree and the frictional force generated by the contact acts only in the circumferential direction, the magnetic head slider is rotated by the contact. This is because vibration occurs not only in the circumferential direction but also in the radial direction perpendicular to the circumferential direction, and as a result, the off-track amount increases.

FIG. 7 shows an example of another inspection procedure performed by using the magnetic head slider inspection apparatus using the read / write tester shown in FIG. In this example, the off-track amount is measured to check the contact state. The details will be described below.
In step 1, the writing frequency W0 is set to the rotation speed N0 and the radius R0.
Write the signal with. In step 2, a signal is written at a write frequency W0 'to a radius R0 + Hd (where Hd is the width of the write head in the track direction). In step 3, the magnetic head slider is moved between the radius R0 and the radius R0 + Hd, and the intensity ratio between the frequency W0 and the W0 'component of the read signal at this time is measured.

In step 4, the head is floated at a position of radius R0 + Hd / 2 (an intermediate position between radius R0 and radius (R0 + Hd)), and a read signal is monitored. Step 5
, The rotational speed is reduced, and the rotational speed N is set to N1. Step 6
Then, the intensity ratio between the frequency W0 and the W0 'component of the read signal at this time is measured, and the deviation T1 in the track direction from the radius R0 + Hd / 2 at which the magnetic head slider is first floated is measured. Note that the writing frequencies W0 and W
0 ′ is W0 × N1 / N0 and W0 ′ × N1 / N0, respectively.
But there is no particular problem.

In steps 7 and 8, it is checked whether or not i is greater than a preset number M. If i is less than M times, Ti and an allowable time interval (tolerable jitter) T
Comparison with p is made for discrimination. Here, if Ti is smaller, i is set to i = i + 1, the constant rotation speed is reduced, and Ti is measured. This operation is repeated, and when i is equal to or less than a predetermined M, Ti
If> Tp, this magnetic head slider is handled as a rejected product. If it passes, the process proceeds to the next step, for example, the inspection of the read / write characteristics of the head.
Note that Tp and M used here are parameters for performing selection in view of the contact strength of the slider.

In the above description, the radius R0 and the radius (R0 +
Hd), the signals W0 and W0 'are written in two places to detect the amount of displacement of the slider in the radial direction when the flying height of the slider decreases, based on the ratio of the amplitudes of the reproduced signals W0 and W0'. What is necessary is just to be able to detect the amount of displacement in the radial direction, and the signal is not necessarily written in two places in advance.

FIG. 8 schematically shows an inspection disk c6 used when a magnetic disk whose surface roughness differs depending on the radial position is used in the inspection apparatus shown in FIG. 1 in order to change the contact state. is there. The inspection disk c shown in FIG. 8 has a zone (0) where the protrusion height Rp, which is one of the parameters indicating the surface roughness in the radial direction, is 6 nm, a zone (1) where it is 5 nm, and a zone (2) where it is 4 nm. Are formed. Here, taking advantage of the fact that the frictional force at the time of contact increases as Rp decreases and the circumferential fluctuation increases, the circumferential fluctuation Δti of the read signal at the position of the radius Ri in the i-th zone is determined. It is measured and compared with an allowable time interval (allowable jitter value) Δtp. The flowchart of the inspection method at this time is shown in FIG.
As shown in FIG.

That is, in the embodiment shown in FIGS. 8 and 9,
Instead of reducing the rotation speed of the disk or reducing the pressure in the disk atmosphere to create a contact state between the slider and the disk, the slider is radially shifted using the disk shown in FIG. Is determined, and the pass / fail judgment is made by measuring the circumferential fluctuation component of the read signal.

FIG. 10 schematically shows an inspection disk d7 used when a magnetic disk whose surface roughness differs depending on the radial position is used in the inspection apparatus shown in FIG. 1 in order to change the contact state. . As shown in FIG. 10, in this test disk d7, Rp continuously changes from about 6 nm to 4 nm from the outer circumference to the inner circumference. The inspection flow is the same as that of FIG. 9, and the magnetic head slider is sequentially moved from the radial position with the larger Rp to the radial position with the smaller Rp to measure Δti. Even when a disk having a continuously changing Rp is used, the magnetic head slider can be selected in the same manner as when a disk having a stepped Rp changes as shown in FIG. .

[0045]

According to the inspection apparatus of the present invention, the fluctuation of the jitter amount is measured and the magnetic head slider is selected, so that the magnetic head slider can be brought into contact with the magnetic disk. Performance can be guaranteed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a magnetic head slider inspection apparatus using a read / write tester according to a first embodiment of the present invention.

FIG. 2 is an inspection flowchart using the inspection apparatus shown in FIG.

FIG. 3 is a diagram showing a form of a read signal read in order to determine a contact strength between a slider and a disk.

FIG. 4 is a diagram showing characteristics of a test disk used in the test apparatus of FIG. 1;

FIG. 5 is a configuration diagram of a magnetic head slider inspection apparatus using a read / write tester according to a second embodiment of the present invention.

6 is an inspection flowchart using the inspection apparatus shown in FIG.

7 is an inspection flowchart of another inspection method (off-track amount measurement) using the inspection device shown in FIG.

FIG. 8 is a view showing another inspection disc used in the inspection apparatus of FIG. 1;

9 is an inspection flowchart when the inspection disk of FIG. 8 is used in the inspection apparatus of FIG. 1;

FIG. 10 is a view showing still another test disc used in the test apparatus of FIG. 1;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Spindle 2 Carriage 3 Magnetic head slider mounting part 4 Magnetic head slider 5, 6, 7 Inspection disk 10 Magnetic head slider inspection device using read / write tester 20 Drive circuit 30 Read / write RW circuit 40 Interval analyzer 50 Control unit 60 Analysis unit 70 Decompression tank 80 Pressure pump

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Ryo Yoshida 2880 Kozu, Kozuhara-shi, Kanagawa Prefecture Storage Systems Division, Hitachi, Ltd. F term in the system division (reference) 5D091 AA08 FF04 HH20

Claims (5)

[Claims] 1. A magnetic disk, a rotating mechanism for rotating the magnetic disk, a magnetic head slider mounting portion, a magnetic head slider positioning mechanism, a read / write circuit for read / write signals, and control for controlling the operation of the entire apparatus. A magnetic head slider inspection apparatus for inspecting a magnetic head slider using a read / write tester comprising: a magnetic head slider, wherein the flying height of the magnetic head slider is sequentially reduced; A time interval variation in the circumferential direction of the magnetic disk between the read signal of the written signal is measured, the time interval variation is compared with a time interval variation allowable value, and the flying height reduction is repeated a specified number of times. A magnetic head slider inspection device, which detects a magnetic head slider and determines whether or not the magnetic head slider is acceptable. 2. A magnetic disk, a rotation mechanism for rotating the magnetic disk, a magnetic head slider mounting portion, a magnetic head slider positioning mechanism, a read / write circuit for read / write signals, and control for controlling the operation of the entire apparatus. A magnetic head slider inspection apparatus for inspecting a magnetic head slider using a read / write tester comprising: a magnetic head slider, wherein the flying height of the magnetic head slider is sequentially reduced; The displacement of the magnetic head slider is measured from the magnitude of the read intensity of the read signal of the written signal in the radial direction of the magnetic disk, and the displacement of the magnetic head slider is compared with the displacement allowance. Magnetic head slider to determine whether the magnetic head slider is acceptable or not. Slider inspection device. 3. The magnetic head slider inspection apparatus according to claim 1, wherein the decrease in the flying height of the magnetic head slider changes the rotation speed of the magnetic disk, or the atmospheric pressure of the magnetic disk and the magnetic head slider. A magnetic head slider inspection device, wherein the inspection is performed by changing 4. A rotating mechanism for rotating a magnetic disk, a magnetic head slider mounting section, a magnetic head slider positioning mechanism, a read / write circuit for read / write signals, and a control section for controlling the operation of the entire apparatus. A magnetic head slider inspection apparatus for inspecting a magnetic head slider using a read / write tester, wherein a parameter indicating the surface roughness of the magnetic disk is set to a projection height R
When expressed by p, the magnetic head slider can be inspected even when it is in contact with a part of the height of the protrusion, the height of the protrusion is uniform on the same circumference of the magnetic disk, and the step is from the inner circumference to the outer circumference. A magnetic disk for inspection, wherein the height of the projections is changed in a shape or continuously. 5. When a gap between a rotating glass disk and a transducer element position of a magnetic head slider is defined as a flying height, the defined flying height is 6 nm or less at normal temperature (20 ° C.) and normal pressure (atmospheric pressure). The gap between the magnetic element of the magnetic head slider and the magnetic film of the magnetic disk when the magnetic head slider is present or on the rotating magnetic disk is 1
A magnetic disk drive equipped with a magnetic head slider having a diameter of 0 nm or less, and a signal written under the condition that the flying height is minimized within the environmental conditions described in the specifications of the magnetic disk device. Is read, the amount of time interval fluctuation in the circumferential direction of the magnetic disk between the read signals of the signals written on the magnetic disk is 0.
A magnetic disk drive characterized by being 1% or less.