JP2682508B2 - Magnetic head tester device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head tester, and more particularly to a magnetic head tester suitable for inspecting a magnetic head used for a hard magnetic disk or the like.

[0002]

2. Description of the Related Art Conventionally, various testers have been used in order to guarantee the electrical, mechanical and tribological characteristics of a magnetic head. For example, in a floating magnetic head for a hard disk, two types of testers are used in a normal manufacturing process: a tester for measuring electrical characteristics and a tester for measuring floating characteristics. The reason for this is that in order to measure the levitation characteristics, it is necessary to measure the levitation clearance between the head and the glass disc by using a glass disc by an optical interference method.

Optical interferometry is the only method for measuring the flying height of the head, except that a special experimental head is used. For this reason, when measuring the flying height at the production site, it was necessary to always use a flying height measuring machine using a glass disk.

[0004]

However, the operation of the flying height measuring machine is an operation that requires extremely complicated and sophisticated techniques such as handling of the head and management of the glass disk, which is inefficient in the production process. It was working.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a magnetic head tester capable of improving the disadvantages of the conventional example and, in particular, capable of simultaneously performing two conventional tests of the flying height and the electrical characteristics in one test. , And its purpose.

[0006]

Means for Solving the Problems To achieve the above object,
Therefore, according to the present invention, there is provided a microvibration detection sensor having a tester main body for detecting the electrical characteristics of a magnetic head in operation and for detecting sliding noise generated between a slider incorporating the magnetic head and a magnetic disk. This small vibration detection sensor
The sliding noise detected by the sensor is processed by the specified signal and output.
It has a signal processing circuit for inputting power.

In addition, the above-mentioned minute vibration detection sensor
Holding the magnetic head assembly equipped with a slider
Mounted on the side surface of the magnetic head assembly holder of the boom mechanism.
You.

Then, the signal output from the signal processing circuit described above is output.
Equipped with sliding noise display means for displaying the noise signal
This sliding noise display means
Memory for storing all noise signals displayed on the display means
Featuring a, it adopts a configuration that.

[0009]

[Operation] The flying start speed (TOV) of the magnetic head is determined by the presence / absence of contact between the magnetic head and the magnetic disk 3. When the floating of the magnetic head is slow, the magnetic head does not fly easily and continues sliding friction with the magnetic disk, while the slider vibrates violently. This vibration is detected by the minute vibration detection sensor 5 as a large output. Then, when the magnetic head floats above the surface of the magnetic disk 3, the slider 4 is not subjected to the vibration due to the sliding on the magnetic disk, and therefore the output of the minute vibration detecting sensor is lost. By monitoring the output of this minute vibration detecting sensor, it is possible to judge whether the flying characteristics of the magnetic head are good or bad.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. First, in FIG. 1, reference numeral 1 denotes a magnetic head assembly, reference numeral 2 denotes an arm mechanism. The arm mechanism 2 is configured so as to hold the magnetic head assembly 1 described above in its distal end. Reference numeral 3 indicates a magnetic disk, and reference numeral 4 indicates a slider mounted at the tip of the magnetic head assembly 1. A magnetic head is mounted on the slider 4.

[0011] Further, in this embodiment, has a tester body for detecting an electrical characteristic of the magnetic head during operation (not shown),
It is provided with a minute vibration detection sensor 5 for detecting sliding noise generated between the slider 4 incorporating the above-mentioned magnetic head and the magnetic disk 3.

[0012] The micro-vibration detecting sensor 5 is instrumentation Bei near the holding portion of the magnetic head assembly 1 described above of the arm mechanism 2. The microvibration detection sensor 5 includes a signal processing circuit 6 that outputs detected sliding noise as predetermined signal processing.

The noise signal output from the signal processing circuit 6 is input to the sliding noise display means 7 and displayed. Further, the sliding noise display means 7 is additionally provided with a memory 8 so that all the noise signals displayed by the sliding noise display means 7 can be stored.

Further, the minute vibration detection sensor 5 described above is
In this embodiment, an AE sensor using a piezoelectric element is used. In addition, this minute vibration detection sensor 5 is specifically
Is mounted on the side surface of the holding portion of the above-described magnetic head assembly 1 of the arm mechanism 2. As a result, minute vibrations generated in the magnetic head assembly 1 can be detected with high sensitivity.

More specifically, in the conventional flying height measurement of the magnetic head (slider 4 portion), the flying height and the flying attitude of the magnetic head are defined when the glass disk for measurement is rotating a predetermined amount. The characteristics are actually checked by measuring the characteristics when the magnetic head starts to fly.

That is, at the start of operation of the entire magnetic disk device, the magnetic disk 3 starts to rotate and then increases in speed, and the floating characteristic from contact start when the magnetic head is lifted to complete floating is measured, It is possible to judge whether the flying of the magnetic head in the magnetic assembly 1 is stable and appropriate.

Specifically, the flying stability of the magnetic head can be determined by knowing the relative speed between the magnetic head and the magnetic disk 3 when the magnetic head (the slider 4 portion) is lifted from the magnetic disk 3.

When the magnetic disk 3 reaches a predetermined rotation, a magnetic head whose flying height is lower than the standard or a magnetic head whose flying attitude is not good are difficult to lift. Therefore, the ascending velocity (take off velocity: TO
V) is larger than that of the magnetic head having the parameter of the design center value. On the other hand, a magnetic head having a load smaller than the design center value or a large air bearing surface area has a smaller flying start velocity (TOV) than the standard magnetic head.

Therefore, by measuring the flying start velocity (TOV), it is possible to fully know the flying characteristics of the magnetic head. Therefore, in such a case, the glass disk used in the conventional example is used. It is not necessary to measure the flying height.

In the present embodiment, in consideration of such characteristics of the flying type head, a magnetic head tester for measuring electrical characteristics is provided with a function for measuring the flying start speed (TOV). It is possible to simultaneously inspect the electrical and tribological characteristics of the magnetic head.

In FIG. 1, as described above, the sensor portion for measuring the electrical characteristics of the magnetic head and the magnetic head assembly 1 are used.
And the relationship with the magnetic disk 3.

The magnetic head assembly 1 is fixed to the tip of the arm mechanism 2 and loaded on the magnetic disk 3 as described above. A slider 4 equipped with a magnetic converter is attached to the tip of the magnetic head assembly 1. The lead wire 4A drawn from the slider 4 is connected to a magnetic head tester main body (not shown), and the electrical characteristics of the magnetic head assembly 1 are inspected.

A micro-vibration detecting sensor 5 composed of an AE sensor is attached to the arm mechanism 2, and a lead wire 5A for taking out a signal is drawn out.

AE (Ac
Since the oustic emission sensor can detect extremely small mechanical vibrations propagating to the sensor mounting portion, the vibration generated by the slider 4 can be detected by the AE sensor through the arm mechanism 2.

By the way, the flying start speed (T
OV) can be determined by the presence / absence of contact between the magnetic head and the magnetic disk 3. When the floating of the magnetic head is slow, the magnetic head does not fly easily and continues sliding friction with the magnetic disk, while the slider vibrates violently. This vibration is detected as a large output by the minute vibration detection sensor 5 which is an AE sensor. Then, when the magnetic head eventually floats up from the surface of the magnetic disk 3, the slider 4 is not subjected to vibration due to sliding with the magnetic disk,
Therefore, the output of the AE sensor disappears.

FIG. 2 shows the output of the AE sensor from when the magnetic disk starts rotating to when it reaches the flying start speed (TOV). In FIG. 2, the point at which the output suddenly increases and then suddenly decreases and reaches a constant value is the flying start velocity (TOV). The constant value is noise due to the magnetic disk 3 continuing to rotate. By monitoring the output of the AE sensor, it is possible to judge whether the flying characteristics of the magnetic head are good or bad.

Thus, the magnetic head tester body for measuring the electrical characteristics of the magnetic head, and the AE sensor capable of detecting the mechanical sliding signal between the magnetic head and the magnetic disk due to the contact start of the magnetic head. Arm mechanism 2
The magnetic head flying speed (TOV) and electrical characteristics of the magnetic head can be obtained by one magnetic head tester in one operation.

As described above, the floating characteristic of the magnetic head can be determined by the AE sensor as described above. However, the AE sensor accompanies the landing of the magnetic head when the rotation of the magnetic disk 3 is stopped. Of course, sliding can also be detected. Therefore, the touchdown speed (touch down velocity: TDV) at the time of contact stop can also be detected.

Therefore, it is also possible to judge the flying characteristic of the magnetic head by the touchdown speed (TDV). Further, it is also possible to determine the stability of levitation by using two values of the levitation start speed (TOV) and the touchdown speed (TDV).

As described above, the ascending start speed (TO
The V) and touchdown speed (TDV) signals can be combined with a magnetic head tester device for inspecting the electrical write / read capability of the magnetic head to realize various functions.

For example, when the flying start speed (TOV) is higher than a predetermined value, a tribological failure of the magnetic head-magnetic disk system is expected, so it is necessary to immediately stop the measurement of electrical characteristics. Becomes Alternatively, when the touchdown speed (TDV) is too low, it is expected that the flying height will be too high and the electrical characteristics will be poor, so the measurement of the electrical characteristics can be stopped. In this way, the inspection can be performed very efficiently.

[0032]

Since the present invention is constructed and functions as described above, according to the present invention, by providing the minute vibration detecting sensor for detecting the sliding noise between the magnetic head and the magnetic disk, the electric It is possible to equip the magnetic head tester that measures the characteristics with the ability to measure the tribological characteristics that can replace the flying characteristics in place of the flying height measurement. Therefore, the conventional flying characteristics and electrical characteristics can be tested with a single inspection. It becomes possible to measure two of them simultaneously, and as a result, it is possible to significantly simplify the flying height measurement, which requires extremely complicated and advanced technology such as handling of the head and management of the glass disk. As a result, it is possible to provide an unprecedented excellent magnetic head tester device capable of significantly improving productivity.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a magnetic head and a magnetic disk that are part of a magnetic head tester according to an embodiment of the present invention.

FIG. 2 is a diagram showing the output of the AE sensor from when the magnetic disk starts rotating to when it reaches the flying start speed (TOV).

[Explanation of symbols]

1 magnetic head assembly 2 arm mechanism 3 magnetic disk 4 slider 5 infinitesimal vibration detection sensor 6 signal processing circuit 7 display means

Claims (1)

(57) [Claims] 1. A microvibration detection sensor having a tester body for detecting electrical characteristics of a magnetic head in operation and for detecting sliding noise generated between a slider incorporating the magnetic head and a magnetic disk. , This small vibration detection sensor
The sliding noise detected by the controller is output after predetermined signal processing.
Device for magnetic head comprising signal processing circuit
In the magnetic f of the micro vibration detection sensor, arm mechanism for holding the magnetic head assembly equipped with a slider to the distal portion
Attached to head assembly holding portion side, as well as provided with a sliding noise display means for displaying the noise signal output from the signal processing circuit, the sliding noise
The display means displays the noise displayed on the sliding noise display means.
A tester device for a magnetic head, which is provided with a memory for storing all the signals .