JPH0423201A - Method and instrument for inspecting magnetic disk medium - Google Patents

Abstract

PURPOSE:To inspect a disk medium fitting in the available status of a magnetic disk device by setting the travel locus of a sensor for inspection, for example, a magnetic head along the surface of the disk medium equally to that of the magnetic head of the magnetic disk device. CONSTITUTION:The magnetic disk medium 1 is mounted and fixed on a spindle. The magnetic head 7a is moved from an original position to the outer side position of the medium 1. The head 7a is loaded on the medium 1, and the medium 1 is rotated via a spindle motor 2, and the head 7a is moved gradually to the inner side of the medium 1. When the head 7a arrives at the innermost side of the medium 1, projection inspection is performed sequentially starting from a track at the inner side. When a projection exists, the burnishing of the track is performed. After the inspection of the outermost track is completed, the rotation of the medium 1 is stopped, and the medium 1 is removed.

Description

[Detailed Description of the Invention] (Summary) Regarding a method and apparatus for testing a magnetic disk medium, which is a magnetic recording medium, of a magnetic disk drive used as a file device of a computer system, the present invention relates to a testing sensor (magnetic head) during testing. By making the YA-angle the same as the YA-angle of the magnetic head of the magnetic disk device, it is possible to inspect the magnetic disk medium according to the usage status of the magnetic disk device, and therefore, the magnetic disk device can be inspected according to the usage status of the magnetic disk device. For the purpose of improving reliability, when the inspection sensor is moved along the surface of the magnetic disk medium, the movement trajectory is made to be the same as the magnetic head movement trajectory of the magnetic disk device.

[Field of Industrial Application] The present invention relates to a method and apparatus for inspecting a magnetic disk medium, which is a magnetic recording medium, of a magnetic disk device used as a file storage for a computer system.

Demand for magnetic disk devices is toward smaller size and larger storage capacity, and the recording density on magnetic disk media continues to increase.

On the other hand, in order to increase the recording density on a magnetic disk medium, it is necessary to lower the flying height of the magnetic head that flies above the magnetic disk medium. Therefore, the surface of the magnetic disk medium is required to have extremely high-precision flatness, and even minute protrusions cannot be tolerated.The same is true for the magnetic recording film, which has extremely uniform characteristics over the entire area of the magnetic disk medium. is required, and even minute characteristic defects cannot be tolerated.

Therefore, there is a need for a method and apparatus for inspecting magnetic disk media with high precision.

[Conventional technology]

(1) Inspection of magnetic disk media There are various inspection items for magnetic disk media, but the items that are becoming more important as the recording density of magnetic disk media increases are the flatness of the surface of the magnetic disk media and the magnetic These include the uniformity of recording film characteristics, etc.

AE (A
A common method is to use a CUSTICE MISSION sensor to capture the impact caused by the protrusions on the surface of the magnetic disk medium.

In addition, a magnetic head is used to test the magnetic recording film characteristics.
A common method is to read a test signal written on a magnetic disk medium and compare the written test signal and the read test signal.

By the way, when inspecting the surface flatness and magnetic recording film characteristics of a magnetic disk medium, the mechanisms used for rotating the magnetic disk medium and moving the inspection sensor are almost the same. Therefore, the configuration and inspection method will be explained using a surface flatness inspection apparatus as an example.

(2) Surface flatness inspection method and inspection device Figure 4 is as follows:
FIG. 2 is a block diagram illustrating a magnetic disk medium testing method and testing device. Note that this figure shows a configuration for inspecting surface flatness.

Technique) Inspection method The surface flatness of the magnetic disk medium 1 is inspected by floating the magnetic head 7 as an inspection sensor on the surface of the rotating magnetic disk medium 1, and detecting fluctuations in the flying height with an AE sensor. done by.

Further, in order to enable inspection over the entire surface of the magnetic disk medium 1, the magnetic heald 7 is moved between the inner side and the outer side of the magnetic disk medium 1.

2) Configuration ■ Spindle motor The spindle motor 2 rotates the magnetic disk medium 1 .

■Motor drive unit The motor drive unit 3 drives and controls the rotation of the spindle motor 2 based on commands from the control unit 6.

(2) To magnetic field, the magnetic hend door levitates above the magnetic disk medium 1 and detects the stability of the levitation.

(2) Support Spring The support spring 8 provides the necessary tension to the magnetic head 7.

(2) Driving Arm The driving arm 10 connects the magnetic head 7 to the driving table 11 and operates in conjunction with the magnetic head 7.

(2) Driving Table and Driving Mechanism The driving table 11 positions and drives the magnetic head 7, and the driving force is provided by a driving mechanism 12 comprising, for example, a spindle motor and a ball screw.

■Table Drive Unit The table drive unit 5 drives the drive mechanism 12 based on commands from the control unit 6.

(2) AE sensor The AE sensor 9 detects fluctuations in the flying height of the magnetic head 7 propagated via the support spring 8.

(2) Protrusion Determination Unit The protrusion determination unit 4 determines the presence or absence of a protrusion on the magnetic disk medium 1 from the detection signal of the AE sensor 9.

[Phase] Control unit The control unit 6 is composed of, for example, a microcomputer, and controls the rotation of the magnetic disk medium 1 and the position of the magnetic heald 7 according to its program, and also determines the presence or absence of protrusions on the magnetic disk medium 1. and remember its location.

3) Operation It operates in the following order:

■From the control unit 6 to the motor drive unit 3, the spindle motor 2
A rotation command is given to rotate and start the magnetic disk medium 1.

(2) A drive command for the drive mechanism 12 is given from the control unit 6 to the table drive unit 5, and the magnetic head 70 is positioned via the drive table 11, the drive arm 10, and the support spring 8, and the magnetic head 7 is moved to the magnetic disk medium 1. Move sequentially from the outer side to the inner side, or from the inner side to the outer side.

■The AE sensor 9 and the protrusion determination unit 4 detect the magnetic disk medium 1.
The presence or absence of a protrusion is determined in the control section 6 and the determination result is
remembers.

The above is the order. That is, it is a mechanism for inspecting the magnetic disk medium 1 by moving the magnetic head 7 in a straight line on the rotating magnetic disk medium 1.

(3) Configuration and operation of protrusion determining section Incidentally, how a protrusion on the magnetic disk medium l can be detected will be explained by giving an example.

FIG. 5 is a diagram illustrating the protrusion determination section and its operation.
) is a block diagram, (b) is a waveform diagram of the amplified output, and (c) is a waveform diagram of the comparison output (protrusion determination output). Furthermore, (b
), the part shown as a band of vertical lines can be observed as a band of bright lines on an oscilloscope.

That is, the magnetic head 7 flying above the rotating magnetic disk medium 1 transmits fluctuations in its flying height to the drive arm 10 via the support spring 8 . The AE sensor 9 attached to the drive arm 10 detects vibrations of the drive arm 10.

Therefore, when a protrusion exists on the magnetic disk medium 1, the flying height of the magnetic head 7 changes rapidly, and the impact can be detected by the AE sensor 9.

An amplifier 13 amplifies the detection output of the AE sensor 9 to a required level, and a comparator 14 compares the amplified output 15 with a reference voltage REF. Then, the reference voltage REF
The comparison output 16 is made active when a signal voltage greater than that is input. That is, the reference voltage REF is a standard for determining protrusions on the magnetic disk medium 1.

FIGS. 5(b) and 5(c) explain the relationship between the amplified output 15, the reference voltage REF, and the comparison output 16, and the time axis is (b).
) (c) Both are the same time.

That is, when the amplified output 15 exceeds the reference voltage REF, the comparison output 16 becomes active, and at the timing when the comparison output becomes active, it can be determined that there is a protrusion on the magnetic disk medium 1.

[Invention tries to solve! l! Title]

(1) Influence of the YA-angle of the magnetic head However, the movement trajectory of the magnetic head 7 during inspection of the magnetic disk medium 1 and the movement trajectory of the magnetic head when the magnetic disk medium is incorporated into an n-air disk device are different. , there are different problems.

This is because most conventional magnetic disk drives used linear magnetic heads, but as magnetic disk drives became smaller, swinging magnetic head drive mechanisms began to be used. .

That is, when inspecting a magnetic disk medium, the magnetic head moves in a straight line, and when used in a magnetic disk device, the magnetic head moves in an arc.

Therefore, between the time of inspection and the time of mounting the magnetic disk medium, a difference occurs in the angle formed by the magnetic head and the rotational direction in the circumference of the magnetic disk medium, that is, the YAl+ angle. Therefore, the attitude of the magnetic head that floats due to the air flow on the surface of the magnetic disk medium differs between when the magnetic disk medium is inspected and when it is assembled into a magnetic disk drive.

The difference in the flying posture of the magnetic head ignores the strictness in testing the magnetic disk medium, and deteriorates the testing accuracy. In particular, as the recording density of magnetic disk media increases, the influence of the flying posture of the magnetic head cannot be ignored.

Incidentally, when testing near the determination reference value, erroneous determinations often occur.

(2) Comparison of YA angle FIG. 6 is a diagram explaining the YAW angle of a magnetic head.
) is a diagram explaining the movement trajectory of the magnetic hand straight-travel type, (b)
2 is a diagram illustrating the YAW angle of the magnetic head linear type, (c) is a diagram illustrating the movement locus of the magnetic head oscillating type, and (d) is a diagram illustrating the YAW angle of the magnetic head oscillating type.

Note that the case where the magnetic head 7 is located at the innermost trunk TKI of the magnetic disk medium 1 is 7 +11.
The case where the magnetic head 7 is located in the trunk TKn on the outermost side is shown as 7+II).

1) When the magnetic head moves straight As shown in FIGS. 6(a) and 6(b), the movement between the magnetic head 7.1° and the magnetic head 7 (Ill) is linear.

Now, the Y of the magnetic head 7.1° in the track TKI
If the A-angle is θ and the YA-angle of the magnetic head 7, n in the trunk TMn is θn, then θ, -θn, and even if the nod 7 moves to the magnetic field, the YAW angle does not change.

Therefore, the direction of the lifting force that the magnetic head door receives from the air flow on the surface of the magnetic disk medium 1 is also constant, and the flying attitude of the magnetic head 7 does not change.

2) When the magnetic head moves in an arc shape In the case of a swinging magnetic head type, the magnetic head 7 moves about the drive shaft 17 via the drive arm 18 and the support spring 8a.

Therefore, as shown in FIGS. 6(c) and 6(d), the magnetic heads 7.1. The movement between the magnetic head 703 and the magnetic head 703 is arcuate.

Now, Y of magnetic head 7(1) in trunk TKI
A-angle +θ1. If the YAW angle of the magnetic head 7° at track TKn is -θnn, then +01°≠
-θnn, and as the magnetic hand arm moves, YA-
The angle changes.

Therefore, the direction of the lifting force that the magnetic head 7 receives from the air flow on the surface of the magnetic disk medium 1 also changes, and the magnetic head 7
The levitation posture of will also change.

(3) Problems The technical problem of the present invention is to solve the above-mentioned problems in the inspection of magnetic disk media, and to change the YAW angle of the inspection sensor (magnetic direction/nod) during inspection to the magnetic direction of the magnetic disk device. By making the YAW angle the same as the throat YAW angle, it is possible to inspect the magnetic disk medium according to the usage status of the magnetic disk device, thereby improving the reliability of the magnetic disk device.

[Means for Solving the Problems] Fig. 1 is a diagram explaining the basic principle of the present invention, in which (a) is a diagram explaining the movement locus of the inspection ° sensor (magnetic head), and (b) is a diagram explaining the movement trajectory of the inspection ° sensor (magnetic head). It is a figure explaining the principle of an apparatus.

(1) Inspection method The inspection method of the present invention includes inspection conditions for a magnetic disk medium,
The feature is that consistency with the usage conditions of the magnetic disk medium is ensured.

That is, when the inspection sensor 19, for example, the magnetic head, is moved along the surface of the magnetic disk medium 1, the inspection method is performed by making the movement trajectory 20 the same as the magnetic head movement trajectory of the magnetic disk device.

(2) Inspection Device The device of the present invention is characterized in that the locus of movement of the inspection sensor 19 on the magnetic disk medium 1 can be freely set.

That is, when the inspection sensor 19, for example, the magnetic head, is moved along the surface of the magnetic disk medium 1, in order to make the movement trajectory 20 the same as the magnetic head movement trajectory of the magnetic disk device, the X table 21 and An X-X table 23, which is orthogonal to the X table 22 and controls the movement amount of the X table 21 and the movement amount of the X table 22 according to a program stored in advance in the control unit 24, is provided with an X-X table 23 for inspection. This is an inspection device equipped with a sensor 19.

[Effect]

(1) Inspection method In the inspection method of the present invention, the movement trajectory of the inspection sensor 19, for example, the magnetic head, is the same as the movement trajectory of the magnetic head of the magnetic disk device.

That is, the YAW angle of the inspection sensor 19 is the same as the YAW angle of the magnetic hend in the magnetic disk device, and the magnetic disk medium 1 can be inspected under the same conditions as the magnetic disk device.

Therefore, the flying attitude of the inspection sensor 19 is equivalent to the flying attitude of the magnetic head in the magnetic disk device.
It becomes possible to test the magnetic disk medium l in accordance with the actual device, and the test accuracy can be increased.

The testing method of the present invention can be applied to testing the surface flatness of the magnetic disk medium 10, testing the uniformity of magnetic recording film characteristics, and the like.

(2) The driving coordinates of the inspection device XX table 23 can be freely controlled and determined by coordinate data included in the program of the control unit 24.

Therefore, in the inspection device of the present invention, the inspection sensor 19
The movement locus can be determined for all types of magnetic disk drives.

As a result, it becomes possible to test the magnetic disk medium l in accordance with the actual device, and the test accuracy can be increased.

The inspection apparatus of the present invention can be used to inspect the surface flatness of the magnetic disk medium 1, the uniformity of magnetic recording film characteristics, and the like.

[Example] Next, how the inspection method and inspection apparatus according to the present invention can be practically realized will be explained using examples.

(1) Configuration FIG. 2 is a bronc diagram for explaining the embodiment.

Note that this embodiment describes a case where the surface flatness of the magnetic disk medium 10 is inspected.

(2) Spindle Motor The spindle motor 2 rotates the magnetic disk medium 1 .

■Motor drive unit The motor drive unit 3 drives and controls the rotation of the spindle motor 2 based on commands from the control unit 25.

■Magnetic head The magnetic head 7a floats C above the magnetic disk medium 1,
The floating stability is detected.

Further, the magnetic head 7a has a vanishing function, and by sliding the magnetic head 7a on the magnetic disk medium 1, the magnetic disk medium 1 can be burnished.

(2) Support spring The support spring 8 provides the necessary tension to the magnetic throat 7a.

■Drive arm The drive arm 10 connects the magnetic nod 7a to the X table 21a.
It is connected and interlocked with.

■X-Y table and drive mechanism The X-table 21a moves horizontally in the diagram,
2a moves in the sewing direction in the figure. Therefore, the magnetic head 7a can be freely positioned on the magnetic disk medium 1.

Further, the driving force of the X table 21a is given by the X table driving mechanism 12xx, and the driving force of the X table 22a is given by the Y table driving mechanism 12xx.
It is provided by the table drive mechanism 12yy.

Note that the drive mechanisms 12xx, 12yy can be composed of, for example, a spindle motor and a ball screw.

■Table drive unit The X table drive unit 5x and the Y table drive unit 5y are
Based on the control unit 250 command, the X table drive mechanism 12
xx and Y table drive mechanism 12yy are driven.

(2) AE sensor The AE sensor 9 detects fluctuations in the flying height of the magnetic head 7a propagated via the support spring 8.

(2) Protrusion Determination Unit The protrusion determination unit 4 determines the presence or absence of a protrusion on the magnetic disk medium 1 from the detection signal of the AE sensor 9.

■Control unit The control unit 25 is made up of, for example, a microcomputer.
According to the program, while controlling the rotation of the magnetic disk medium 1 and the position of the magnetic head 7a, the presence or absence of protrusions on the magnetic disk medium 1 and their positions are memorized.

The movement locus of the magnetic head 7a is determined according to the type of medium to be inspected (magnetic disk medium 1) used, and is programmed in the control section 25 in advance.

(2) Operating procedure FIG. 3 is a flowchart illustrating the operating procedure of the embodiment.

Next, the operation will be explained according to the work procedure. still,
In principle, the operations of each part are performed based on commands from the control section 25. Therefore, in the explanation of the operation, the controlling entity is omitted.

(2) Attach and fix the magnetic disk medium 1, which is the medium to be inspected, to the spindle.

■Move the magnetic head 7a from the origin position to the magnetic disk medium 1.
Move to outer side position 1 (load position).

Note that the origin position of the magnetic head 7a is a position that does not pose a problem when attaching/removing the magnetic disk medium 1.

(2) The magnetic head 7a is loaded onto the magnetic disk medium by a vertical mechanism (not shown).

(2) Start the spindle motor 2 and rotate the magnetic disk medium 1.

Incidentally, the rotational speed of the magnetic disk medium 1 is selected to be approximately 60% of the rotational speed under actual use.

(2) Slowly move the magnetic head 7a from the outer side of the magnetic disk medium 1 to the inner side.

That is, at this time, the magnetic disk medium l is burnished.

(2) When the magnetic head 7a reaches the innermost side of the magnetic disk medium 1, the protrusion inspection is performed in order from the innermost track.

If it is determined that there is no protrusion, the next track is inspected for protrusions.

■If it is determined that there is a protrusion, the C5S of the magnetic head 7a (CONTACT
START 5TOP). That is, at this time,
Vanish a track with protrusions.

Then, the trunk protrusion inspection is performed again, and if it is determined that there is no protrusion, the next trunk protrusion inspection is performed.

■After inspecting the protrusion up to the last track (the outermost track), stop the rotation of the spindle motor 2,
The rotation of the magnetic disk medium 1 is stopped.

(2) The magnetic head 7a is unloaded from the magnetic disk medium 1 by a vertical mechanism (not shown).

■Move the magnetic hand door a to the home position.

@Remove the magnetic disk medium 1 from the spindle and end the inspection of the magnetic disk medium 1.

(3) Other Examples In (1) and (2) above, flatness inspection of magnetic disk media was explained as an example. It is also possible to test film properties.

However, in that case, a test mold device capable of writing/reading and comparing test data is connected to the magnetic head 7a for testing, and the error judgment output of the cough testing device is transmitted to the control unit. The input deviation to 25 is L.

Incidentally, when the magnetic recording film characteristic horizontal 1 of the magnetic disk medium 1 is performed, it is not necessary to perform the burnish operation of the magnetic disk medium 1. Therefore, the inspection is performed using a program in which the burnish operation is deleted. [Effects of the Invention] As described above, according to the present invention, the YA-angle of the magnetic head (inspection sensor) when inspecting a magnetic disk medium is
It can be made the same as the magnetic head YAI+angle of the magnetic disk device.

Therefore, it is possible to make the flying posture of the magnetic head when inspecting a magnetic disk medium equal to the flying posture of the magnetic head when the magnetic disk medium is used in a magnetic disk device.

As a result, when inspecting a magnetic disk medium, it becomes possible to perform highly accurate inspection with extremely good reproducibility, and the reliability of the magnetic disk device can be improved.

[Brief explanation of the drawing]

FIG. 1 is a diagram illustrating the basic principle of the present invention, and (a) is a diagram illustrating the movement locus of the inspection sensor (magnetic head);
(b) is a diagram explaining the principle of the inspection device, FIG. 2 is a block diagram explaining the embodiment, FIG. 3 is a flowchart explaining the operating procedure of the embodiment, and FIG. 4 is a diagram explaining the magnetic disk medium. FIG. 5 is a block diagram illustrating the inspection method and inspection device, and is a diagram illustrating the protrusion determination section and its operation.
) is a block diagram, (b) is a waveform diagram of the amplified output, (c) is a waveform diagram of the comparison output (protrusion determination output), and FIG. 6 is a diagram explaining the YAW angle of the magnetic head. (a) is a diagram illustrating the movement locus of a linear magnetic head;
b) is a diagram illustrating the YA-angle of a straight magnetic head; (c)
) is a diagram explaining the movement trajectory of the magnetic hand swing type, (d)
FIG. 2 is a diagram illustrating the YAW angle of a magnetic head swing type. In the figure, 1 is a magnetic disk medium, 2 is a spindle motor, 3 is a motor drive unit, 4 is a protrusion determination unit, 5 is a table drive unit, 5X is a χ table drive unit, 5y is a Y table drive unit, and 6 is a control unit , 7, 7a are magnetic heads, 8, 8a
9 is a support spring, 9 is an AE sensor, 10 is a drive arm, 11
is the drive table, 12.12x, 12y are the drive mechanisms,
12xx is an X table drive mechanism, 12yy is an X table drive mechanism, 13 is an amplifier, 14 is a comparator, 15 is an amplified output, 16 is a comparison output, 17 is a drive shaft, 18 is a drive arm, 19 is an inspection sensor (magnetic head ), 20 is a movement locus, 2L21a is an X table, 22.228 is a Y table, 23.23a is an XY table, 24 is a control unit, and 25 is a control unit, respectively. Fude 2 Aki=Ijiri 2nd z The 4th ward (C) The 4th ward (C) The sudden action of the ugly person (b) (d) To the stones 71' 17IYA W Ryo 6th District Procedural Amendment (Method) Case Description 1990 Patent Application No. 127458 Title of Invention Magnetic disk medium inspection method and inspection bag! 3゜Representative person making the amendment Name: Takuma Yamamoto Name: Fujitsu Limited (7259) Patent attorney Tesada Iyuki 7゜Drawing subject to amendment 721

Claims (1)

[Claims] 1. A method for inspecting a magnetic disk medium (1), which is a magnetic recording medium, used in a magnetic disk device, the method comprising ), the movement locus (20) is made the same as the magnetic head movement locus of the magnetic disk drive. 2. A device for inspecting a magnetic disk medium (1) that is a magnetic recording medium used in a magnetic disk device, which moves an inspection sensor (19) along the surface of the magnetic disk medium (1). In this case, in order to make the movement locus (20) the same as the magnetic head movement locus of the magnetic disk device, the X table (21) and the Y table (22) are orthogonal to each other, and the X table ( The X-Y table (21) and the Y table (22) are controlled according to a program stored in advance in the control unit (24).
3) A magnetic disk medium inspection device characterized in that an inspection sensor (19) is attached.