JPS60129907A - Magnetic reproducer - Google Patents

Abstract

PURPOSE:To attain the reproduction of signals with an extremely high S/N and high sensitivity by setting inductances of the primary and secondary sides orthogonal to each other for a high-frequency coupling circuit having its coupling degree changing with the high-frequency characteristics of a magnetic substance due to a signal magnetic field given from a magnetic recording medium. CONSTITUTION:An inductance element 7 of the primary side is obtained by forming a thin film conductor on the end face of the 1st substrate 10. While an inductance element 8 of the secondary side is obtained by coating a thin film conductor on the plane of the 2nd substrate 11 at the area near a magnetic recording medium 1. A magnetic substance 9 is obtained by providing a minute magnetic substance between the substance 11 and the thin film conductor forming the element 8. The high frequency energy which is produced by the electromagnetic connection secured between both elements 7 and 8 in terms of an electric circuit and transmitted to the secondary side from the primary side can be extremely suppressed since those elements 7 and 8 are orthogonal to each other. Thus this energy is almost equal to the changing component of a signal magnetic field. This ensures the reproduction of signals with an extremely high S/N and high sensitivity.

Description

[Detailed Description of the Invention] [Technical Field of Defense] The present invention relates to a device for reproducing signals recorded on a magnetic recording medium, and in particular to a device that reproduces signals recorded on a magnetic recording medium, and in particular, utilizes changes in the high frequency characteristics of a magnetic material due to a signal magnetic field from the magnetic recording medium. The present invention relates to a magnetic reproducing device for reproducing signals.

[Technical background of the invention and its problems] The conventional magnetic recording and reproducing method using an in-plane oriented magnetic recording medium uses a ring-shaped magnetic head, and in the case of recording, current is passed through the winding of the head. The magnetic field generated in the gap between the heads magnetizes the medium and records signals, while for reproduction, the electromotive force induced by the signal magnetization of the medium is extracted as a reproduction output. In this system, the shorter the recording wavelength, the stronger the demagnetizing field effect becomes, making the recording more efficient.Furthermore, the ring-shaped head itself is originally an 11-bundle detection type, and as for reproduction, the ring-shaped head itself is originally an 11-flux detection type. Since the magnitude of the reproduction output depends on the 1-rack width, it is essentially disadvantageous for high-density recording and reproduction.

On the other hand, the recently proposed perpendicular magnetic recording/reproduction method records in such a way that the signal magnetization is perpendicular to the surface of the medium, so there is no negative effect from demagnetizing fields and recording signals can be recorded with short wavelengths. This enables more stable recording and is essentially suitable for high-density recording. However, playback is still of the magnetic flux detection type, and since the magnitude of the C playback output depends on the track width, from the standpoint of S/N and playback sensitivity, there is a natural limit to increasing the density, especially in the track width direction. be. - Therefore, a method has been proposed in which reproduction is performed by detecting a signal magnetic field from a magnetic recording medium. This method uses a magnetic head with an inductance element coupled to a magnetic material, and uses this magnetic head as one of the tuning elements to configure a tuning circuit. Changes in the magnetic field from the magnetic recording medium cause the magnetic material constituting the magnetic head to change. The tuning frequency changes due to changes in magnetic permeability, or the Q of the tuning circuit changes due to changes in the magnetic field from the magnetic recording medium, or both of these are used to extract changes in the tuning frequency and Q as changes in voltage. This is what I did. According to this method, even a slight change in the signal magnetic field from the magnetic recording medium causes a large voltage change, and therefore it is possible to obtain a reproduction output with an extremely good S/N ratio even if the recording track width is narrow. This enables high-density recording and reproduction.

In general, magnetic materials with high magnetic permeability used in magnetic heads cause a ferromagnetic resonance absorption phenomenon in the high frequency range, and the accompanying magnetic permeability and loss at high frequencies change significantly even with changes in the weak external magnetic field. show. Therefore, the above-mentioned method of detecting the signal magnetic field using a magnetic material and performing reproduction is theoretically suitable for a narrow 1-rack width, since the reproduction output level depends on the strength of the signal magnetic field and does not depend on the Txt flux. Suitable for high-density magnetic recording and reproduction.

By the way, a magnetic reproducing device using this method includes a high-frequency coupling circuit in which the degree of coupling changes due to a change in the high-frequency characteristics of a magnetic material caused by a signal magnetic field, and detects changes in the high-frequency output voltage from this high-frequency coupling circuit to generate a signal. A device in which the playback output is reduced by 1q has already been proposed. In this case, how to make the change in the degree of coupling of the high frequency coupling circuit sensitive to the change in the high frequency characteristics of the magnetic material due to the signal magnetic field becomes an important issue in performing signal reproduction with high sensitivity and high S/N.

[Objective of the Invention] An object of the present invention is to record data at high density with a narrow track width so that the coupling degree of the high frequency coupling circuit changes greatly due to the change in the high frequency characteristics of the magnetic material due to the signal t+i field from the magnetic recording medium. A signal with high sensitivity and good I S
,/N [Summary of the Invention] This defense is based on a magnetic reproducing device that is capable of reproducing data with a signal magnetic field from a magnetic recording medium, and the degree of coupling changes due to a change in the high frequency characteristics of a magnetic material. The coupling circuit is configured by arranging a primary inductance element to which a high frequency signal is supplied on the base layer side of the magnetic recording medium and a secondary inductance element on the recording layer side so as to face each other at right angles, The secondary inductance element is configured to be coupled with the magnetic material, and the signal recorded on the magnetic recording medium is extracted and reproduced as a change in the high frequency output voltage of the high frequency coupling circuit.

[Effects of the Invention] According to the present invention, the primary and secondary inductances of a high frequency coupling circuit whose degree of coupling changes depending on the high frequency characteristics of the magnetic material due to the signal magnetic field from the magnetic recording medium are opposed so as to be perpendicular to each other. Therefore, there is almost no electromagnetic coupling between the two in the form of an electric circuit, but if the signal magnetic field from the magnetic recording medium causes a change in the high-frequency characteristics of the magnetic material, such as a change in Tentzle permeability due to the ferromagnetic resonance phenomenon, the two The degree of connectivity between them changes greatly.

Therefore, a change in the signal recorded on the magnetic recording medium causes a large change in the electromagnetic coupling of the high-frequency coupling circuit, and the amount of high-frequency energy flowing into the secondary side changes greatly. Only the energy is transmitted to the secondary side, making it possible to reproduce signals with extremely high S/'N and high sensitivity.

Furthermore, since the primary and secondary inductance elements are opposed to each other with the magnetic recording medium in between, the high-frequency magnetic field generated by the high-frequency signal supplied to the primary side is generated by the magnetic material. As the characteristics change, the magnetic material is located on the same recording layer side as the secondary inductance, and the tip part near the medium surface, that is, the area where the signal magnetic field based on the high-density recording signal with a short recording wavelength is concentrated. Applied from For this reason, the m-type material is more likely to cause ferromagnetic resonance at the tip of the magnetic material, and in this respect, highly sensitive reproduction can be expected on the shorter wavelength side.

[Example of explanation] The figure shows an example of the present invention. 1 is a magnetic recording medium running in the direction of the arrow, 2 and 3 are its base layer and recording layer, 4 is a recording track, and 5 is a recorded signal magnetization. A regeneration radar 6 according to the invention is arranged.

The reproduction head 6 includes an elongated plate-shaped or IHtA-shaped primary inductance element 7 arranged along the length direction of the recording 1 to rack 4 on the base layer 2 side of the magnetic recording medium 1, and a primary inductance element 7 arranged on the recording layer 3 side. A secondary inductance element 8, also in the form of an elongated plate or thin film, is arranged in the width direction of the recording track 4.
, and a magnetic body 9 which is coupled to the secondary inductance element 8 and has its high frequency characteristics changed by the signal magnetic field from the magnetic recording medium 1.

As for the specific mounting structure of the reproducing electrode 6, for example, the primary inductance element 7 can be formed by depositing a thin film conductor on the end surface of the first substrate 10, and the secondary inductance element 7 can be formed by depositing a thin film conductor on the end surface of the first substrate 10. 8 also for the second substrate 1
It can be formed by depositing a thin film conductor on a plane near the recording medium 1 of 1 m. As for the magnetic material 9, a fine thin film magnetic material may be deposited between the substrate 11 and the thin film conductor constituting the secondary inductance element 8.

The primary side inductance element 7 constitutes the primary side tuning circuit of the high frequency coupling circuit together with the tuning capacitor 12, and the secondary side inductance element 8 similarly constitutes the secondary side tuning circuit of the high frequency coupling circuit together with the tuning capacitor 15. Configure the circuit. The tuning frequencies of these primary and secondary tuning circuits are made to match or almost match.

When a high frequency signal is supplied from the high frequency source 14 to the primary side tuning circuit via the high frequency coupling capacitor 13, a high frequency magnetic field is generated from the primary side inductance element 7, and this is coupled with the magnetic body 9. Here, since the primary inductance element 7 and the secondary inductance element '8 are orthogonal to each other, there is almost no electromagnetic coupling as an electric circuit. However, when the magnetic recording medium 1 is moved in the direction of the arrow while in contact with the magnetic material 9, the signal magnetic field formed by the signal magnetization 5 is applied to the magnetic material 9, so that the tuning frequency is changed to the magnetic material 9 due to its ferromagnetic nature. When tuned to a frequency that causes resonance absorption, the tensor permeability of the Urn magnetic material changes due to changes in this signal magnetic field. As a result, the inductance element 7
．． 8 causes a large electromagnetic coupling, and high frequency energy corresponding to changes in the signal magnetic field flows from the primary side tuning circuit of the high frequency coupling circuit to the secondary side tuning circuit. Therefore, a high frequency output voltage corresponding to the change in the signal magnetic field appears across the capacitor 15 of the secondary side tuning circuit. Therefore, by detecting this with the peak detection circuit 16, the magnetic recording medium 1
It is possible to obtain a reproduction output 17 of the signal recorded in the .

In this way, since the inductance elements 7 and 8 are in an orthogonal relationship, the high frequency energy transmitted from the primary side to the secondary side is due to electromagnetic coupling between the two inductance elements 7 and 8 as much as possible. is suppressed and consists mostly of changes in the signal magnetic field. Therefore, it has the advantage of being able to reproduce signals with extremely high S/N and high sensitivity.

Furthermore, since the high-frequency magnetic field is applied to the magnetic body 9 from the primary inductance element 7 through the magnetic recording medium 1, the detection sensitivity to the signal magnetic field in the short wavelength range that exists very close to the surface of the medium 1 is improved, and Since the detection sensitivity to the signal magnetic field in the region is relatively lowered, it becomes more advantageous for reproducing high-density recorded signals with short recording wavelengths, and the reproduction frequency band is also expanded particularly to the high frequency side.

It should be noted that the present invention is not limited to the above-mentioned embodiment, and for example, an appropriate DC bias magnetic field may be applied to the magnetic body 9 as necessary. Further, when the magnetic recording medium is a perpendicular magnetic recording medium, a similar effect of 1q can be obtained. Furthermore, the means for detecting the reproduced signal may be a means for amplifying the high frequency signal appearing at both ends of the tuning capacitor 15 before detecting the signal, and then performing peak detection.

[Brief explanation of drawings]

The figure is a diagram showing the configuration of a magnetic reproducing device according to an embodiment of the present invention. 1... txt recording medium, 2... base layer, 3...
- Recording layer, 4... Recording track, 5... Signal magnetization,
6... Reproduction head, 7... Primary side inductance element, 8... Secondary side inductance element, 9... Magnetic material, io, il... Substrate, 12.15... Tuning Capacitor for use, 13... Capacitor for high frequency coupling, 14
...High frequency source, 16...Peak detection circuit. 11 applicants Patent attorney Takehiko Suzue

Claims (3)

[Claims] (1) It has a high frequency, wave coupling circuit in which the degree of coupling changes due to the change in the high frequency characteristics of the magnetic material due to the signal magnetic field from the magnetic recording medium, and from this high frequency coupling circuit based on the change in the degree of coupling of this high frequency coupling circuit. In a magnetic reproducing device that detects a change in a high frequency output voltage of a magnetic recording medium and reproduces a signal recorded on the magnetic recording medium, the high frequency coupling circuit is arranged on a base layer side of the magnetic recording medium and is supplied with a high frequency signal. a primary inductance element, and a secondary inductance element arranged on the recording layer side of the magnetic recording medium so as to face orthogonally to the primary inductance element and coupled to the magnetic material. A magnetic reproducing device characterized by: (2) The high frequency coupling circuit is characterized in that the degree of coupling between the primary inductance element and the secondary inductance element changes due to magnetic resonance of the magnetic body caused by a magnetic field. The magnetic reproducing device according to item 1. (3) In a high-frequency coupling circuit, when there is no signal magnetic field, there is almost no electromagnetic coupling between the primary inductance element and the secondary inductance element, and large electromagnetic coupling occurs due to the magnetic resonance of the magnetic material caused by the signal magnetic field. A magnetic reproducing device according to claim 2, characterized in that: