JPS59139119A - Magnetic head - Google Patents

Abstract

PURPOSE:To obtain a magnetic head proper for high track density also and improved in its production cost and efficiency by setting up the width of a magnetic pole to the width equal to the track width at the end surface of a head opposed to a medium and wider than the track width at a position separated from the end surface and specifying the distance between the wide magnetic pole part and the end surface. CONSTITUTION:A thin film magnetic pole 301 is set up to the width equal to the recording track width 303 at its head end surface 306. The thin film magnetic pole is almost rectangular to the end surface 306 on both sides of the width 303 and the width of the magnetic pole 301 is expanded at a position separated from the end surface 306 by almost fixed length. The distance 302 is set up to a value at least almost equal to recording wavelength or more so that a recording and erasing magnetic field is included in a prescribed range. In is preferable to set up the distance 302 in a range of 1-20mu as an experimental value and to an almost fixed value of the distance 302 within the width 304.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to magnetic heads, and more particularly to magnetic heads having thin film magnetic poles for erasing on both sides of a data recording head.

In a magnetic recording/reproducing device, a magnetic storage medium (tape,
The relative positional relationship between the recording or reproducing magnetic head (disc, etc.) and the recording or reproducing magnetic head, especially the positional relationship with respect to the width direction of the data track, does not have a large effect on the signal quality such as the output level of the reproduced signal and the signal-to-noise ratio. Generally, in this type of device, a cartridge or cassette-shaped magnetic medium is shared between multiple devices, and it is inevitable that the relative position of the head and the medium will fluctuate due to the influence of the operating temperature and humidity environment. do not have. Ideally, the track position of data previously recorded on the medium and the track position of the magnetic head set on the medium to newly reproduce the data or update the data should be the same. It is desirable that they match exactly. Normally, the track position to be reproduced is such that it does not overlap any other data track that is included in or momentarily contacts the data track that is being recorded.

Magnetic recording and reproducing devices are designed to satisfy the above-mentioned conditions and to minimize track deviation. For this reason, the magnetic head is also designed to have the following structure. Hereinafter, conventional embodiments of the magnetic head according to the present invention will be explained with reference to the drawings.

FIG. 1 shows the structure of a magnetic head widely used in floppy disk drives. The upper side shows the medium facing surface of the head core section.

The shaded area is made of a magnetic core (9), and the other parts are made of a non-magnetic material. 101 is a recording/reproducing head gap;
Reference numeral 102 is for erasing a certain width on both sides of the recorded data immediately after recording the data when recording data using the rad gap in the recording/reproduction dual-purpose disk. In particular, when the track position of data recorded on the same track on the medium before the data recording is shifted from the data recording position, old data outside the data recording position is
It is erased by 02. Figure 10 on the bottom of Figure 1
3 represents a head assembly, 104 a data recording/reproducing coil, and 105 an erasing coil.

! Figure 2 shows part of a head used in rigid disks, etc., which have a higher track density than floppy disks. 201 is a part of the 3-bed flower, and 202 is a helad core part, both of which are usually made of magnetic material. 201 and 202 are attached so as to obtain a predetermined gap length. The diagram on the right side of FIG. 2 shows an external cross-section of the head core 202 in the vicinity of the gap in the track width direction. As shown in the figure, both sides of the medium facing surface of the core are tapered 203 relative to the medium surface.

The data recording track width is 204. The erase width is indicated by 205. Here, the taper is formed by mechanically grinding or polishing the core block at a predetermined angle and with a predetermined track width of 2.
04, the machining accuracy is extremely strict and the machining is difficult. Further, it is difficult to set the erase width 205 to a stable value because the amount of outward bleeding of the data width 204 changes depending on the data recording wavelength, and the width of the erasable magnetic field changes depending on the recording current. As is clear from the figure, in the above-mentioned floppy disk head, there are an extremely large number of members that make up the head, and the processing accuracy of each member is strict, resulting in high processing costs. Also, the precision required when assembling the parts together is very strict, which tends to cause variations in performance. When increasing the track density to increase the storage capacity of media, it is necessary to reduce the thickness of the recording/reproducing head core and consumer rad core, but there is a limit to the thickness of the core flakes that can be handled during the manufacturing process. However, it is difficult to manufacture a head with the structure shown in FIG. 1 for high track density.

The present invention has been made to address the above-mentioned problems and drawbacks of the conventional head structure, and an object of the present invention is to provide a head that is suitable as a head for high track density and is excellent in terms of manufacturing cost and performance. .

Furthermore, the purpose of the present invention is to provide a head structure that allows the recording section and the erasing section to be placed close to each other, and enables erasing with the same recording coil, and allows arbitrary recording track widths and erasing track widths to be designed in accordance with the device specifications. do.

The structure of the magnetic head according to the present invention will be described below based on examples.

FIG. 3 is a diagram showing the structure of the tip of a thin-film magnetic pole of a magnetic head having a thin-film magnetic pole according to the present invention.

FIG. 4 shows the structure of the main part of a magnetic head composed of five magnetic poles having the structure according to the present invention. The structure of a general thin film head is well known and will not be described here. FIG. 3 shows the structure of the magnetic pole tip according to the present invention, and is equivalent to an enlarged view of the portion 404 in FIG. 4. FIG. 3 is a plan view of the thin film magnetic pole part, that is, a view in the track width direction, and the head end face is 306. The magnetic medium is indicated by a dashed line 305.

The thin film magnetic pole 301 has a width equal to the recording track width 303 at the end face 306 of the head.
Data is recorded with a width equal to 03. On both sides of the width 303, the thin film magnetic pole is approximately perpendicular to the head end face 306, and the width of the thin film magnetic pole becomes wider at a distance from the end face 306 by a substantially constant length 302. The expansion of the magnetic pole width is indicated by 304. The distance 302 between the end face 306 and the wide-width magnetic pole must be determined in close relation to the data recording wavelength, but when the recording wavelength is usually from several microns to 1 micron or less, the distance 302 is also from several microns to 1 micron or less. Set to about 10-odd microns. It is set to be at least equivalent to the recording wavelength, and set so that the recording and erasing magnetic fields by the magnetic pole of the head 6, which will be described later, fall within the desired range. As an empirical value, it is preferable that the distance 302 be approximately constant within the width 304 and within the range of 1 micron to 20 microns. FIG. 4 shows the main parts of an embodiment of the core structure and coil structure of a head having a magnetic pole structure according to the present invention. 401.402 is a thin film magnetic pole, 40
3 is a coil. The magnetic pole tip structure shown in Figure 3 is
It is sufficient to form the magnetic poles on both magnetic poles 01 and 402.

In addition, only the magnetic pole on the rear side with respect to the head movement direction relative to the medium has the structure shown in FIG. 3, and the magnetic pole on the opposite side has a structure in which the magnetic pole reaches the head end face 306 over the entire width 303 and width 304. Very good.

FIG. 5 shows the distribution of the recording magnetic field in the vicinity of the nuclear pole tip of the head having the magnetic pole tip structure according to the present invention. The vertical axis represents the magnetic field strength, and the horizontal axis represents the distance in the track direction (track width direction r (perpendicular direction)) centered on the magnetic pole part.Curve 5 in the figure
01 is the magnetic field distribution within the recording track width 303, a curve 502
corresponds to the magnetic field distribution within the region 7- of width 304. A dashed-dotted line 503 represents the magnetic field strength level required for recording or erasing on a magnetic medium. Width 3
Within 0.03, the magnetic field distribution exhibits a steep gradient of 5°1, data is recorded based on the recording signal, and magnetization remains on the medium. In the area of width 304, the magnetic field distribution shows a gentle gradient as shown in 502, and the polarity of the magnetic field is reversed according to the change in the recorded data pattern. The magnetization is so-called AC erased, and no magnetization remains. The present invention allows recording and erasing to be performed simultaneously and selectively with the same recording signal and with the same magnetic pole by providing such different magnetic field distributions in the data recording area and the erasing area of the head, respectively.

6 shows an embodiment in which the core on one side is composed of a bulk magnetic material 601, which is different from FIG. 4.
The figure shows an example in which the magnetic pole 701 and coil 702 shown in FIG. 4 are sandwiched between two non-magnetic materials 703 to complete a head. The magnetic head according to the present invention can be realized in various other embodiments in addition to the above-mentioned embodiments, but all of these belong to the present invention.

As described above, in the magnetic head of the present invention, since the recording track width and the erasing track width for erasing both sides of the recording track width can be formed only by patterning the thin film magnetic pole, they can be easily and accurately formed by mask formation, etc. I can do that. In addition, as a result, the characteristics of the head, such as shape and dimensions, can be processed and formed uniformly, eliminating the problems of variations in conventional heads, the large number of Fi manufacturing steps, the large number of parts, and the processing process. The problem is resolved. Furthermore, it can cope with an increase in track density without any problem.

[Brief explanation of the drawing]

FIG. 1 (at (bl) is a magnetic head with an erasing core that is conventionally used in floppy disk drives and the like. FIG. 2 1α11b1 is a tapered magnetic head that is used in rigid disks and the like. Figure 3,
Figure 4 Cα1 (61, Figures 6 and 7 show examples of the magnetic head according to the present invention. Figure 5 shows the recording and erasing magnetic field distributions of the head according to the present invention. 101-・Rad gap portion 102 for recording 102-φ Rad gap portion 203 for erasure・Tapered portion 301.401, 402, 701・・Thin film magnetic pole 403.
702... Suil 501.502... Above the magnetic field distribution curve Applicant Suwa Seikosha Co., Ltd. Agent Patent Attorney Mogami -1+1- Figure 3 Figure 4 Figure 6 Figure 70

Claims (1)

[Claims] It has a magnetic pole made of a high permeability magnetic thin film, and the width of the magnetic pole is equal to the recording track width at the end surface facing the medium of the head, and the @ of the magnetic pole is equal to the recording track width when separated from the end surface by a substantially constant distance from the medium. 1. A magnetic head characterized in that the magnetic pole is widened by a certain width, and the distance between the wide magnetic pole part and the end face is 1 to 20 microns.