JPH0328756B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a floating head that floats on the surface of a magnetic disk or the like with a minute interval, and in particular detects contact with the magnetic disk floating head caused by protrusions, defects, etc. on the surface of the magnetic disk. The present invention relates to a floating head with an element.

The floating head floats on the magnetic disk surface rotating at high speed while maintaining a minute spacing on the order of submicrons due to the action of hydrodynamic force.
It is important to keep this gap small and stable in order to improve the performance of the floating head. However, if the floating head and the magnetic disk come into contact due to protrusions, defects, etc. on the surface of the magnetic disk, it becomes difficult to maintain the above-mentioned gap stably.
It is important to prevent contact between the magnetic disk and the floating head.

Conventionally, protrusions, defects, etc. on the surface of a magnetic disk are detected using an AE (acoustic emission) sensor bonded to a floating head holding arm 3 that holds a magnetic disk 2 floating above a magnetic disk 1, as shown in FIG. 4. Alternatively, as shown in FIG. 2, the signal from the piezoelectric element 5 provided on the surface opposite to the floating surface of the floating head 2 may be amplified and processed by a preamplifier and detection circuit (not shown). Ta. However, in these methods, since the detection element senses the movement of the floating head, it is easily affected by external vibrations, and also when the floating head has multiple floating surfaces (sliders), such as the commonly used floating head. The disadvantage of this method is that detection accuracy is reduced because the floating head and the protrusion come into contact with each other at multiple positions for a single protrusion.

The present invention provides a floating head equipped with a protrusion detection element that eliminates the above drawbacks, is less susceptible to external influences, and dramatically improves detection accuracy.

In order to achieve this object, in the present invention, a piezoelectric transducer is used as a protrusion detection element, and the piezoelectric transducer is placed on the floating surface side of the floating head and at the minimum gap where the end thereof is closest to the surface of the recording medium. The piezoelectric transducer is arranged so as to be in direct contact with the protrusion of the recording medium.

Hereinafter, the present invention will be explained with reference to Examples. FIG. 3 is a view of the floating head 2 according to one embodiment of the present invention, viewed from the floating surface side. The floating head 2 has two floating surfaces 10 on either side. floating head 2
A bimorph piezoelectric transducer 20 is fused to the side surface 11 at the rear end, which is the smallest gap, using low-melting glass. The end surface 21 of the piezoelectric transducer 20 on the floating surface side is polished so as to be flush with the two floating surfaces 10. By amplifying and processing the output from the piezoelectric transducer 20 using a preamplifier and a detection circuit (not shown),
A protrusion on the magnetic disk 1 is detected.

FIG. 4 shows a state in which the floating head 2 of FIG. 3 is floating above the magnetic disk 1. The magnetic disk 1 consists of an aluminum substrate 100 and a magnetic coating film 102 formed by applying a magnetic material containing a filler 101 onto the substrate. The surface of this magnetic coating film 102 has protrusions 1 due to defects during coating.
03 or the filler 101 remaining after processing protrudes. The magnetic disk 1 is rotating at high speed in the direction of the arrow, and the floating head 2 is coated with a magnetic coating 102.
It floats with a minimum floating gap h with respect to the surface of .
If this minimum floating gap h is larger than the height of the protrusion on the surface of the magnetic coating film, there is nothing that comes into contact with the end surface 21 of the piezoelectric transducer 20 on the floating surface side, so no detection output is generated. When the minimum floating gap h becomes smaller and becomes lower than the height of the protrusion, the end surface 21 of the piezoelectric transducer 20 comes into contact with the top of the protrusion, and an output piezoelectrically converted according to the contact is supplied to the detection circuit.

According to the present invention, since the piezoelectric transducer is directly deformed by contact with the protrusion, a larger detection output can be obtained compared to the conventional example. Further, the protrusion detection portions provided on the floating head 2 are located at the end face 211 of the piezoelectric transducer 20, and since the end face 21 is located on the floating surface side, it is not affected by the movement of the floating head. In addition to being less susceptible to external vibrations, it no longer generates multiple outputs corresponding to all of the multiple floating surfaces as in the conventional example, significantly improving detection accuracy.

In the above embodiment, the piezoelectric transducer 20 and the protrusion of the magnetic disk 1 are in direct contact with each other. The wear resistance of the parts can be improved.

As explained above, according to the present invention, detection can be performed by direct contact between the protrusion detection section on the floating head and the protrusion on the recording medium, so a large detection output can be obtained, and the same protrusion can be detected only once. Since only the magnetic recording head is detected, the detection accuracy is improved, and it becomes possible to detect protrusions on the recording medium more reliably, which has a significant effect on improving the reliability of a magnetic recording device using a floating head.

[Brief explanation of drawings]

1 and 2 are views showing a conventional floating head, FIG. 3 is a three-dimensional view showing the floating head of the present invention, and FIG. 4 is a view showing the operating state of the floating head of the present invention. DESCRIPTION OF SYMBOLS 1... Magnetic disk, 2... Floating head, 10... Floating surface, 20... Piezoelectric conversion element.

Claims (1)

[Claims] 1. In a floating head that floats with a minute gap with respect to a moving recording medium, a piezoelectric transducer is disposed on the floating head, and a detection section of the piezoelectric transducer A floating head characterized by being located at the smallest part of the gap. 2. The floating head according to claim 1, wherein the piezoelectric transducer is arranged on a side surface of the floating head. 3. The floating head according to claim 1 or 2, wherein the detection portion of the piezoelectric transducer is made of a highly hard material. 4. A floating head according to claim 3, wherein the high hardness material is alumina.