JPS6233320A - Head for magnetic disc - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an apparatus capable of optically measuring a minute gap between a magnetic disk and a magnetic head, and simultaneously measuring electromagnetic conversion characteristics.

<Prior Art> In a magnetic disk drive, the size of the gap between the magnetic head and the magnetic disk has a large effect on electromagnetic conversion characteristics. In a hard disk drive, a magnetic head floats with a small gap above a magnetic disk that rotates at high speed. Furthermore, in a floppy disk drive, a minute gap is created between the magnetic head and the disk due to factors such as surface roughness of the disk, waviness of the disk, and vibration of the magnetic head. On the other hand, as the density of magnetic disks increases, the gap between the magnetic head and the magnetic disk must be kept stable at submicron or less, and there is a need to measure this gap with high precision. In particular, in the case of a floppy disk, the gap between the head and the disk is 0.1 μm or less, and measurement at a submicron level or less is required.

The present inventors have previously provided the following device as a device for measuring this minute gap.

That is, an optical head made of a transparent material such as glass is placed close to the top of a magnetic disk as an object to be measured, and incident light of a specific wavelength is made to pass through the optical head and enter the surface to be measured of the magnetic disk. Thereby, the configuration is such that a minute gap between the optical head and the surface to be measured is measured by measuring interference fringes caused by interference between light reflected from the lower surface of the optical head and light reflected from the surface to be measured.

This device can accurately measure minute gaps, but if the gap between the magnetic disk and the magnetic head changes, the electromagnetic conversion characteristics also change, so it is desirable to be able to measure changes in the electromagnetic conversion characteristics at the same time as measuring the gap. However, since the above-mentioned apparatus has a head made of optical glass or plastic, it was not possible to simultaneously measure electromagnetic conversion characteristics.

For this reason, the inventors further applied for patent application No. 59-165563.
In this paper, we provided a method and apparatus that can measure the minute gap between a magnetic disk and a magnetic head, and at the same time measure changes in magnetic conversion characteristics. The present invention is an improvement on this device.

<Problems to be Solved by the Invention> The device previously provided by the present inventors that can simultaneously measure minute gaps and magnetic conversion characteristics does not necessarily have a practical method of integrating a magnetic head and an optical head. It was constructed in consideration of the fact that there are some structural difficulties in installing it on an actual machine, and it is a device with a more practical configuration.

<Means for Solving the Problems> The present invention is configured to solve the above problems, and includes a magnetic core that measures the electromagnetic conversion characteristics between the head and the disk in the carriage. This device is equipped with a measuring section that is configured to be held between an optical head or the like that optically measures the gap.

<Examples> Examples of the present invention will be specifically described below with reference to the drawings.

1 and 2, reference numeral 1 is an optical chip, 2 is an optical slider, 3 is a magnetic core, 4 is a winding wound around this magnetic core, 5 is a magnetic conductor, 6 is a magnetic disk, and 7 is a magnetic core. is the incident light. Of these, the optical head 1 and the optical chip 2 are made of a transparent material such as glass or plastic, and the gap between them 1.2 and the magnetic disk is measured as described later. The magnetic core 3 is the same as that currently used, has a function of performing electromagnetic conversion, and is capable of recording and reproducing. This magnetic core 3 is connected to the optical chip 1 and the optical slider 2 by adhesive means or the like. With this structure, the magnetic core 3 is held between the optical chip 1 and the optical slider 2, and the magnetic head 5 is constituted by these members. The magnetic head 5 is attached to a carriage (not shown) that moves between the inner and outer circumferential sides of the magnetic disk.

Next, the operating state of this device will be explained mainly with reference to FIG.

First, the magnetic head 5 is placed above the disk 6, and monochromatic light or white light is made to enter as incident light 7 from above the magnetic head. At this time, the light incident on the optical chip 1 and the optical slider 2 of the magnetic head 5 is reflected by the lower surface of the optical chip 1 and the lower surface of the optical slider 2, respectively, and becomes reflected light 7a. Further, the light reflected by the surface 6a of the magnetic disk 6 becomes reflected light 7b, and the re-reflected lights 7a and 7b interfere with each other to produce interference fringes. In this case, if the wavelength of the incident light 7 is λ, monochromatic light, and n is the interference order, then the gap d is d
= mλ/2, it becomes a dark line, and d=(2n+1)/4
It becomes a bright line when . Therefore, by measuring these interference fringes, the gap d at the position of the magnetic head can be measured.

Moreover, when the incident light 7 is white light, the interference fringes are formed in the gap d
Therefore, by inputting the relationship between the gap d and the interference color into a measuring device (not shown) in advance, the gap d can be measured.

On the other hand, the magnetic core 3 can measure the electromagnetic conversion characteristics and simultaneously perform recording and reproduction of electrical signals on the disk 6. In other words, with this configuration, it is possible to measure the gap side and the electromagnetic conversion characteristics of the magnetic head at the same time, so it is possible to accurately grasp the interface between the magnetic head and the magnetic disk.

Effects> According to the present invention, it is possible to simultaneously measure the electromagnetic conversion characteristics of the magnetic disk and the minute gap between the magnetic head and the magnetic disk, and it is possible to measure the electromagnetic conversion characteristics that have conventionally been impossible to obtain experimentally. It has now become possible to clarify the relationship between this and minute gaps.

In addition, since the magnetic core is sandwiched between an optical chip made of a transparent material and an optical slider, it is possible to measure the gap between the head and the disk around the magnetic core. Driving stability and electromagnetic conversion characteristics can be improved.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a magnetic head showing an embodiment of the present invention, and FIG. 2 is a side view of the magnetic head showing a measurement state by the magnetic head of FIG. 1... Optical chip 2... Optical slider 3...
・Magnetic core 5...Magnetic head 6...Magnetic disk 1 Figure 1: Inuwoya + Tsufu' 2: χ door? Slab 7" 3: Magnetic core 6;

Claims (1)

[Claims] In the structure of a magnetic head used for magnetic disks such as floppy disks, the magnetic head is constructed by sandwiching a magnetic core between an optical chip made of a transparent material and an optical slider, and the optical chip and the optical slider are connected to the magnetic head. A magnetic disk head characterized in that the magnetic core measures the minute gap between the magnetic disk and the magnetic disk, and the magnetic core measures the electromagnetic conversion characteristics.