JPS58153270A - Floating head - Google Patents

Abstract

PURPOSE:To avoid the influence of outside vibrations and to improve the detecting accuracy, by arranging a piezoelectric crystal element in such a way that the element is installed to the floating surface side of a floating head and the end face of the element is positioned in the minimum clearance section which is the nearest to the surface of a recording medium. CONSTITUTION:A floating head 2 has two floating surfaces 10 at both sides and a piezoelectric crystal element 20 is melt-stuck on the side face 11 at the rear end of the minimum clearance section of the floating head 2 by means of a low- melting-point glass. The end face 21 of the floating surface of the piezoelectric crystal element 20 is polished so that the surface 21 lies in the same plane as the two floating surfaces 10. The floating head 2 floats with a minimum floating clearance (h) against the surface of the magnetic coated film 102 of a magnetic disk 1, and, when the minimum floating clearance (h) becomes smaller and lower than the height of the projection at the surface of the magnetic coated film, the end face 21 of the piezoelectric crystal element 20 contacts with the top of the projection and a piezoelectrically converted output is supplied to a detecting circuit in accordance with the contact.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a floating head that floats on the surface of a magnetic disk with a minute gap, and in particular detects contact with the magnetic disk floating head caused by protrusions, defects, etc. on the surface of the magnetic disk. This relates to a floating spatula t equipped with all elements.

The floating head floats on the surface of a magnetic disk rotating at high speed by maintaining a minute gap 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 dot comes into contact with the magnetic disk due to a protrusion or defect on the surface of the magnetic disk, it will be difficult to maintain the above-mentioned gap stably. It is important to prevent head contact.

Conventionally, protrusions, defects, etc. on the surface of a magnetic disk are detected using a magnetic head 2 floating above a magnetic disk 1, as shown in FIG.
AE (
acoustic emission) sensor 4 or
As shown in FIG. 2, this is accomplished by amplifying and processing a signal from a piezoelectric element 5 provided on the opposite surface of the floating surface of the floating head 2 using a preamplifier and a detection circuit (not shown). However, in these methods, since the detection element senses the movement of the floating head, it is susceptible to external vibrations.In addition, like the commonly used floating head, it has multiple floating surfaces (sliders). In this case, the floating head and the protrusion come into contact with each other at a plurality of positions for a single protrusion, resulting in a reduction in the detection area.

The present invention provides a floating head in which the protrusion detection element is biased, which eliminates the above-mentioned drawbacks and, in addition, dramatically improves the detection accuracy despite external influences.

In order to achieve such an 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 whose end is closest to the surface of the recording medium with a minimum gap. 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. Figure 3 shows
FIG. 2 is a diagram of a floating head according to an embodiment of the present invention viewed from the floating surface side. The floating head 2 has two floating surfaces 10 on both sides. A bimorph piezoelectric transducer 20 is fused to the side surface 11 at the rear end of the floating head 2, which is the smallest gap, using low-melting glass. This piezoelectric transducer 20
The end face 21 on the floating surface side is polished to be flush with the two floating surfaces 10. Piezoelectric conversion element 20
The output from the sensor is amplified and processed by a preamplifier and a detection circuit (not shown).

A protrusion on the magnetic disk 1 is detected.

4 is a diagram showing a state in which the floating head 2 of FIG. 3 is floating above the magnetic disk 1; FIG. The magnetic disk consists of a 1σ 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 1020 has protrusions 103 due to defects during coating or fissures 10 remaining due to processing.
1st place stands out. The magnetic disk 1 is rotating at high speed in the direction of the arrow, and the floating head 2 is floating on the narrow surface of the magnetic coating 102 with a minimum floating gap.

If this minimum floating gap is larger than the height of the protrusion on the surface of the magnetic coating, there is nothing that comes into contact with the floating surface side end surface 21 of the piezoelectric transducer 20, so no detection output is generated. When the minimum floating gap 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 in response 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. In addition, since it is located on the top side of the floating head 2,
Since it is not affected by the movement of the floating head, it is less susceptible to external vibrations, and it eliminates the need for multiple outputs corresponding to all of the multiple floating surfaces as in the conventional case, significantly improving detection accuracy. do.

In the above embodiment, the piezoelectric transducer 20 and the projection of the magnetic disk 1 are in direct contact with each other, but by bonding a high hardness material such as alumina to the end 21 of the piezoelectric transducer 20, The wear resistance of the detection part 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 it is not detected, the detection nt degree is improved, and protrusions on the recording medium can be detected more reliably, resulting in a remarkable effect on improving the reliability of a magnetic recording device that fully utilizes the floating head.

[Brief explanation of the drawing]

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.
The figure is a diagram showing the operating state of the floating head of the present invention.

Claims (1)

[Claims] 1. A floating head that floats while maintaining a minute gap with respect to a moving recording medium, including a piezoelectric transducer element disposed above the floating head so that one end is located at the smallest part of the minute gap, and the piezoelectric transducer element A floating head characterized in that it is formed by detecting protrusions on the surface of the recording medium.