JPS60138703A - Magnetic reproducing device - Google Patents

Abstract

PURPOSE:To reproduce a signal recorded with high density on a narrow track while keeping high sensitivity and excellent S/N by arranging inductance elements orthogonally to a recording layer of a magnetic recording medium while clipping a magnetic substance to form a high-frequency coupling circuit. CONSTITUTION:A support base 11 made of a high-hardness insulating material is arranged vertically in opposition to a recording layer 1 of the magnetic recording medium 3, the secondary side inductance element 7b made of a band- shape thin film conductor in the broadwise direction of a recording track 5 is formed on the tip side face of the base 11 with coating, a thin film magnetic substance 6 is formed through coating so that a part of the lower end is overlapped on the element 7b and the primary-side inductance element 7a made of a band-shape thin film conductor is formed through coating so as to be orthogonal to the element 7b on the magnetic substance 6. As a result, a high-frequency signal applied to the primary side of the high-frequency coupling circuit appears at the secondary side as a change in an output of the high-frequency signal through the change in the degree of coupling by the change of the high-frequency characteristic of the magnetic substance 6 and a signal reproducing output 16 is formed by a peak detection circuit 15.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a device for reproducing magnetically recorded signals,
In particular, the present invention relates to a magnetic recording and reproducing apparatus that performs reproduction by utilizing changes in the high frequency characteristics of a magnetic material due to changes in a signal magnetic field formed by a magnetic recording medium.

[Technical pre-invention! Conventional magnetic recording and reproducing devices use a ring-shaped magnetic head, and when recording, the magnetic recording medium is magnetized by a signal magnetic field generated in the gap between the heads. For reproduction, the electromotive force induced in the head due to changes in magnetic flux from the medium was extracted as reproduction output. In this method, when using a magnetic recording medium with in-plane orientation, the shorter the recording wavelength, the stronger the demagnetizing field effect becomes, making recording difficult, and the ring-shaped magnetic head is a magnetic flux detection type even during playback. As a result, the reproduction output depends on the track width, which is fundamentally disadvantageous for recording and reproduction of high curvature.

On the other hand, the perpendicular magnetic recording method, which has recently been attracting attention, records by directing the signal magnetization in a direction perpendicular to the surface of the magnetic recording medium, so it has the characteristic that recording becomes more stable when the recording wavelength is shortened. This method is suitable for density recording. However, even with perpendicular magnetic recording, a magnetic flux detection method such as a ring-shaped head or a head configuration consisting of a main magnetic pole and a sub-magnetic pole is conventionally used for reproduction, so the reproduction output depends on the track width as in the case of in-plane orientation. subject to restrictions.

By the way, the magnetic reproducing device proposed in Japanese Patent Application No. 110340/1983 is equipped with a magnetic material that detects changes in the signal magnetic field from a magnetic recording medium as changes in characteristics such as magnetic permeability and high frequency loss. Regeneration is performed by utilizing changes in inductance of a coil (inductance element) wound around the oscillator. In this device, the coil constitutes a tuned circuit together with a capacitance element, and a high-frequency signal is supplied to this tuned circuit. In this case, changes in the characteristics of the magnetic material caused by the strength of the signal magnetic field from the magnetic recording medium cause changes in the resonant frequency and Q of the tuning circuit, causing the high frequency signal to undergo amplitude modulation. By detecting it with a detection circuit, a reproduced output can be obtained.

The magnetic permeability and loss at high frequencies of the high-permeability magnetic material used in this method change significantly even with changes in a weak external magnetic field, and as mentioned above, the signal magnetic field cannot be detected by this magnetic material. When reproduction is performed, the reproduction output level depends on the strength of the signal magnetic field and does not depend on the magnetic flux, so that high-density magnetic reproduction with an extremely narrow track width is theoretically possible.

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 that obtains a playback output has already been proposed (Special Application No. Sho-1). In this case, how to increase the change in the coupling degree of the high frequency coupling circuit with respect 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] The 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 changes in the high-frequency characteristics of the magnetic material due to the signal magnetic field from the magnetic recording medium. It is an object of the present invention to provide a magnetic reproducing device capable of reproducing signals with extremely high sensitivity and good S/N ratio.

[Summary of the Invention] ゛The present invention provides a primary side inductance element and a secondary
The next inductance element is placed on the recording layer side of the magnetic recording medium,
A magnetic material is sandwiched between the pixel elements and arranged orthogonally to each other, and the high frequency signal output based on the change in the degree of coupling of this high frequency coupling circuit is detected to reproduce the signal recorded on the magnetic recording medium. It is characterized by

[Effects of the Invention] According to the present invention, a signal magnetic field from a magnetic recording medium is detected by changing the degree of coupling of a high-frequency coupling circuit by using changes in high-frequency characteristics such as tensor permeability of a magnetic material caused by a signal magnetic field. Because the inductance elements on the primary and secondary sides that make up the high-frequency coupling circuit are orthogonal, there is almost no electromagnetic coupling when there is no signal, and the high-frequency output obtained from the high-frequency coupling circuit is small. When a signal magnetic field is applied to a magnetic material, new electromagnetic coupling occurs due to tensor magnetic permeability, and this appears as a large change in high frequency output.
Signal reproduction output with high sensitivity and good S/N ratio can be obtained.

In addition, in order to arrange both the primary side and secondary side inductance elements constituting the high frequency coupling circuit on the recording layer side of the magnetic recording medium together with the magnetic material, it is possible to laminate them on one support base, for example. This has the advantage that the playback head can be integrated in a compact manner.

[Embodiments of the invention] FIG. 1 shows an embodiment of the present invention.

A recording track 5 based on signal magnetization 4 is formed on the recording layer 1 of a magnetic recording medium 3 consisting of a recording layer 1 and a base layer 2, and a magnetic material 6 whose high frequency characteristics change due to the signal magnetic field caused by the signal magnetization 4 is formed on this recording medium 3. are placed in contact with and facing the recording track 5.

The magnetic body 6 is a plate-shaped or thin-film magnetic body, and a primary inductance element 7a is provided in contact with one surface thereof. This primary side inductance element 7a constitutes an LCC tuning circuit path together with a tuning capacitor 8a, and this LCC
CIiiili1! A high frequency signal is supplied to the circuit from a high frequency oscillator 9 via a high frequency coupling capacitor 10.

Further, a secondary inductance element 7b is provided in contact with the other surface of the magnetic body 6 so as to be geometrically perpendicular to the primary inductance element 7a. This secondary inductance element 7b also constitutes an LC tuning circuit together with the tuning capacitor 8b. This secondary side LC tuning circuit and the primary side L
A high frequency coupling circuit is formed by the C tuning circuit and the magnetic body 6. Here, the oscillation frequency of the high frequency oscillator 9,
The tuning frequencies of the LC tuning circuits on the primary side and the secondary side of the high frequency coupling circuit are made substantially the same.

The specific mounting structure of the high frequency coupling circuit configured in this way is, for example, as shown in the figure, a high frequency coupling circuit made of high hardness insulating material such as glass or sapphire, facing the recording layer 1 of the magnetic recording medium 3. A supporting base 11 is arranged vertically, and a secondary inductance element 7b made of a strip-shaped thin film conductor is formed on the side surface of the leading end side of the supporting base 11 in the width direction of the recording track 5. Element 7b
A thin film magnetic body 6 is deposited so that its lower end side partially overlaps the magnetic body 6, and a primary inductance 7a made of a strip-shaped WIM conductor is disposed on the magnetic body 6 so as to be perpendicular to the secondary inductance element 7b. It is sufficient to deposit and form.

When the primary inductance element 7a and the secondary inductance element 7b are orthogonal to each other as described above, there is almost no electromagnetic coupling in the high frequency coupling circuit due only to the two inductance elements 7a and 7b. However, the inductance elements 7a, 7
Since there is a magnetic material 6 between b, when the magnetic material 6 receives a signal magnetic field from the signal magnetization 4 in the recording track 5 and causes a change in high frequency characteristics such as magnetic resonance, high frequency coupling occurs via the magnetic material 6. Electromagnetic coupling between the primary side and the secondary side of the circuit is newly generated due to the tensor magnetic permeability of the magnetic body 6.

Therefore, the high frequency signal supplied to the primary side of the high frequency coupling circuit appears as a change in the high frequency signal output on the secondary side due to a change in the degree of coupling due to a change in the high frequency characteristics of the magnetic body 6 caused by the signal magnetic field. Therefore, by detecting this high frequency signal output with a detection circuit, for example, a peak detection circuit 15 consisting of a diode 12, a resistor 13, and a capacitor 14, a signal reproduction output 16 is obtained as a detection output.

In this way, 1. When there is no signal, there is almost no electromagnetic coupling in the electric circuit of the high-frequency coupling circuit, so the component obtained as the high-frequency signal output on the secondary side is mainly due to changes in the signal magnetic field, which makes it possible to achieve high sensitivity. , high S/N signal reproduction output can be obtained. Furthermore, since both the primary and secondary sides of the high-frequency coupling circuit are arranged on the recording layer side of the magnetic recording medium, it is easy to integrate the reproducing head, which is extremely advantageous in terms of device configuration.

FIG. 2 shows another embodiment of the present invention, in which a conductive film for shielding is provided between the primary inductance element 7a and the magnetic body 6 via an insulating film 18 on the primary inductance element 7a side. A body membrane 17 is arranged. According to this embodiment, the effect of suppressing electromagnetic coupling due to orthogonality between the primary inductance element 7a and the secondary inductance element 7b is further increased by the shielding effect of the conductive film 17, so that the S/N of the signal reproduction output 16 is increased. This can be further improved.

Note that the present invention is not limited to the embodiments described above, and the present invention can be similarly applied, for example, to cases where the magnetic recording medium is an in-plane oriented recording medium or a perpendicular magnetic recording medium. In addition, when configuring a high frequency coupling circuit, in order to reduce electromagnetic coupling that is not based on changes in high frequency characteristics of the magnetic body 6, inductance elements 7a and 7b on the primary side and the secondary side are used.
A means for adjusting the relative arrangement of the two may be added. Furthermore, it goes without saying that a bias magnetic field may be applied to the magnetic body 6 in order to reduce electromagnetic coupling when there is no signal or to increase changes in the high frequency characteristics of the magnetic body 6.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of a magnetic reproducing apparatus according to one embodiment of the present invention, and FIG. 2 is a diagram showing another embodiment. DESCRIPTION OF SYMBOLS 1... Recording layer, 2... Base layer, 3... Magnetic recording medium, 4... Signal magnetization, 5... Recording track, 6...
...Magnetic material, 7a, 7b...Primary side and secondary side inductance elements, 8a, 8b...Tuning capacitor,
9... High frequency oscillator, 10... High frequency coupling capacitor, 11... Support base, 15... Detection circuit, 16
...Signal reproduction output, 17...Conductor film for shielding. Figure 1 Figure 2

Claims (1)

[Scope of Claims] (1) A high-frequency coupling circuit whose degree of coupling changes due to a change in the high-frequency characteristics of a magnetic material due to a signal magnetic field from a magnetic recording medium, and a high-frequency output based on a change in the degree of coupling of this high-frequency coupling circuit. In an apparatus for detecting a change in voltage and reproducing a signal recorded on the magnetic recording medium, the high frequency coupling circuits are arranged opposite to the recording layer side of the magnetic recording medium and orthogonal to each other with the magnetic body interposed therebetween. The primary and secondary
A magnetic reproducing device comprising a next-side inductance element. ('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 the magnetic resonance of the magnetic body caused by the signal magnetic field. The magnetic reproducing device according to paragraph 1. (3) In the 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 the magnetic coupling is large due to the magnetic resonance of the magnetic body. The magnetic reproducing device according to claim 1 or 2, characterized in that the magnetic reproducing device generates electromagnetic coupling. (4) The magnetic body and the primary and secondary inductance elements are supported on the same side. A magnetic reproducing device according to any one of claims 1 to 3, characterized in that the magnetic reproducing device is formed in layers on a base.