JPS58196618A - Magnetic recording and reproducing head - Google Patents

Abstract

PURPOSE:To extract only an effective signal containing the reduced noises, by providing plural magnetic poles having windings around them in opposition to a vertically magnetized recording medium and adding a differential amplifier which performs magnetic recording/reproducing with the 1st magnetic pole and then obtains the output difference between the 1st magnetic pole and another. CONSTITUTION:For instance, a main magnetic pole 2 is set at the side of a magnetic material 4 of a vertically magnetized recording medium 1, and auxiliary magnetic poles 31 and 32 having even characteristics are provided opposite to the pole 2. In this case, the pole 31 is set opposite to the pole 2 and the polse 32 is set close to the pole 31. The outputs of the poles 31 and 32 are fed to a differential amplifier 5. The reproduced signal of a recorded signal emerges only at the pole 31. When an external magnetic field has a fluctuation, the induced voltage due to this fluctuation emerges both at poles 31 and 32. Then only an effective signal containing the reduced noises is obtained by a differential amplifier 5. It is also effective to use two main magnetic poles instead of two auxiliary magnetic poles and to extract a difference signal out of the windings of main magnetic poles 21 and 22.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention magnetically records and reproduces information on a magnetic medium having an axis of easy magnetization in a direction perpendicular to the plane of the magnetic medium. The present invention relates to a magnetic recording/reproducing head using a so-called perpendicular magnetization recording method.

The first type of head used for perpendicular magnetic recording and reproduction is
As shown in the figure, a main magnetic pole 2 made of a magnetic thin film that determines the recording wavelength and an auxiliary magnetic pole 3 for generating a recording magnetic field and detecting a reproducing magnetic field are arranged on both sides of a magnetic recording medium 1. head is generally known. In this head, the magnetic material 4 formed on the main magnetic pole 2 side of the magnetic medium 1 is magnetized by the main magnetic pole 2 excited by the auxiliary magnetic pole 3 to record information, and furthermore, during reproduction, the recorded information of the magnetic material 4 is The main magnetic pole 2 is excited by the magnetic field,
The magnetic field generates a reproducing voltage across the extension line of the auxiliary magnetic pole 3, thereby obtaining a signal. By the way, this type of head does not have a magnetically closed magnetic path, so
It has the disadvantage of being weak against external magnetic fields; that is, induced voltage is easily generated due to changes in the external magnetic field, which becomes noise in the reproduced signal.

An object of the present invention is to provide a magnetic recording/reproducing head that alleviates the above-mentioned drawbacks.

An example of this will be described below. As shown in FIG.
and 32 are prepared, one auxiliary magnetic pole 31 is arranged to face the main magnetic pole 2, and the other auxiliary magnetic pole 32 is arranged near the first auxiliary magnetic pole 31 without facing the main magnetic pole 2,
This will be the second auxiliary magnetic pole. At this time, the outputs of these two auxiliary magnetic poles 31 and 32 are input to the differential amplifier 6. When reproducing a recorded signal, the reproduced signal appears only on the first auxiliary magnetic pole 31. However, when fluctuations in the external magnetic field that affect the magnetic poles occur, induced voltages due to this occur in both the first and second auxiliary magnetic poles 31 and 32. That is, an effective signal and noise are generated in the first auxiliary magnetic pole 31, but only noise is generated in the second auxiliary magnetic pole 32, and by inputting these signals to the differential amplifier 5, its output is From this, a signal containing only effective signals with reduced noise can be obtained.

FIG. 3 shows another embodiment of the invention.

This embodiment is a case of main pole excitation, in which a first main pole 21 is placed on the magnetic material 4 side of a magnetic recording medium 1 provided with a magnetic material 4.
Second main magnetic poles 22 are provided, and the differential amplifier 6 extracts a difference signal from the windings provided on the first main magnetic pole 21 and the second main magnetic pole 22, respectively. Reference numeral 3 denotes an auxiliary magnetic pole, which is provided as required. In this embodiment as well, by taking the signal difference between the first main magnetic pole 21 and the second main magnetic pole 22, it is possible to remove noise due to fluctuations in the external magnetic field, etc.

Although the above embodiment has been described with respect to an example in which there are two magnetic poles, the same applies to a structure in which three or more magnetic poles are provided and the reproduction signal is obtained from the difference signal between the first magnetic pole and the other magnetic poles. Effects can be obtained.

As described above, the present invention provides a plurality of magnetic poles facing a recording medium magnetized perpendicularly to the film surface and having windings around the periphery, performs magnetic recording and reproduction with the first magnetic pole, and performs magnetic recording and reproduction with the first magnetic pole. This method calculates the difference in output between one magnetic pole and another magnetic pole, and has the advantage of being able to reduce noise caused by the influence of external magnetic fields.

[Brief explanation of the drawing]

FIG. 1 is a front view showing the configuration of a conventional perpendicular magnetic recording/reproducing head, and FIGS. 2 and 3 are front views showing the configuration of a magnetic recording/reproducing head in an embodiment of the present invention. 1...Magnetic recording medium, 2IIo...Main magnetic pole,
3... Auxiliary magnetic pole, 4... Magnetic material, 6
... Differential amplifier, 21 ... First main magnetic pole, 22 ... Second main magnetic pole, 31 ...
First auxiliary magnetic pole, 32...Second auxiliary magnetic pole 1, Name of agent: Patent attorney Toshio Nakao and 1 other person 1st
Figure 3 21st! I 6 31st! I

Claims (1)

[Claims] facing a recording medium that is magnetized in a direction perpendicular to the film surface,
A plurality of magnetic poles each having a winding around the periphery are provided, a first magnetic pole of the plurality of magnetic poles is used to perform magnetic recording and reproduction, and another magnetic pole is disposed at a position away from the first magnetic pole. A magnetic recording/reproducing head characterized in that a differential amplifier is provided for determining the difference between the outputs from the windings of the first magnetic pole and the other magnetic poles.