JPS5972644A - Magnetic double layer recording medium - Google Patents

Abstract

PURPOSE:To attain high recording density and high track density, by forming a pattern corresponding to a servo signal to a lower magnetic layer, by the etching method, then magnetizing uniformly, and using an upper magnetic layer to data recording. CONSTITUTION:A magnetic substance layer 5 is formed on a nonmagnetic base 8, a pattern corresponding to the servo signal is formed by the etching method, and a buffer layer 4, a magnetic layer 3 for data recording and a protecting film 2 are formed on it. A magnetic substance 5 is magnetized uniformly in the track direction in advance. A data signal is recorded on a data track of the upper magnetic substance layer 3 having a track center at the boundary line of an adjacent servo track 9, two kinds of servo signals from two adjacent servo tracks 9 are detected separately from the data signal to obtain a position error signal. Thus, the high recording density and the high track density are realized.

Description

[Detailed Description of the Invention] The invention relates to a magnetic recording device that enables high recording distance and high track density by accurately aligning mottling and grooves with desired data tracks, and particularly relates to a magnetic recording device that enables high recording distance and high track density. The present invention relates to a double layer recording medium in which a data signal and a data track position signal (hereinafter referred to as a servo signal) are present.

Concentric circles on the surface of the magnetic recording medium 5. BACKGROUND ART In a magnetic recording device that records data, it is constantly necessary to align a magnetic head for recording and reproduction with a desired data track. To increase the precision of alignment between the magnetic throat and the desired data track, a method was developed, published in Japanese Patent Publication No. 41-2586.
As described in detail in the publication, there is a method of using an 11fl double layer disk as a CR magnetic recording medium.

In other words, two magnetic disks with different coercive forces are placed on a non-magnetic disk substrate.
Form two magnetic layers such that the coercive force of the lower layer is higher than the coercive force of the upper layer.1. In a 11-bay double-layer disk, the servo signal recorded on the lower layer and the data signal recorded on the upper layer are simultaneously read out using a magnetic field. This method separates the signals and aligns the obtained servo signal forces 1 and 2 on the desired data track. In order to record servo signals using magnetism/RAD, if the coercive force is increased, the servo signal may not be recorded, so as a result, it is necessary to use a magnetic material with a sufficiently large coercive force. This has the disadvantage that the lower layer cannot have a sufficiently large coercive force, and as a result, when recording data signals on the upper layer, the influence of the magnetic/\rad write magnetic field is ignored. The lower layer is affected and the servo signal deteriorates.

The purpose of the present invention is to improve the recording density by reducing the
An object of the present invention is to provide a magnetic recording medium that enables recording and reproduction at a commercial track density.

According to the present invention, data information is recorded in the upper magnetic layer in the form of tracks, and a coercive force greater than that of the upper magnetic layer is formed in the lower magnetic layer. In a magnetic recording medium in which positional information of the data tracker 2 of the upper magnetic layer is obtained, the lower halide layer is etched (obtained by partially removing the magnetic material from this). By forming the magnetization pattern of Mi so as to generate track position information of the layer, a double layer recording medium capable of high recording density and high track density recording can be obtained.1. Ru.

The configuration and effects of the invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a first embodiment of the uninvented double layer recording medium, in which the RDI layer 1 is parallel to the recording direction of the medium.

Example 0) Magnetic double film recording medium 1 (magnetic layer 5 is formed on a non-magnetic substrate 8 in the form of 1j5i, the magnetic layer 5 is partially removed using an etching method, and a surface layer is formed on it. Forms a single layer 3 for recording data on a smooth (as in this phrase, a non-magnetic buffer @ 4) layer (7, and then Q),
On top of that, a protection layer 2 is formed to prevent damage such as contact with llf'4 and \rad (the 6 straight layer 3C/). The magnetic layer 5 is uniformly distributed in the trunk direction.

Then, magnetic flux 7 caused by magnetization 6 leaks from the end face.

This leakage magnetic flux 7 is recorded in the iron two M layer NLE! 1≠Leakage occurs on the surface of the body 1, so a magnetic head detects this leakage magnetic field 7 to obtain a low-frequency servo signal.

By changing the arrangement of the magnetic layer 5, that is, the magnetization pattern, various servo signals can be obtained and formed on the 6° nonmagnetic substrate 8.1. The magnetic layer 5 (formed by, for example, plating method) 1. Co, Ni, Mn,
A material made of P is used, and a material with high coercive force is selected. This (magnetic layer 5 is partially etched using an etching method, and a DC magnetic field is applied uniformly along the track direction to magnetize it).
(1) can be done after or before pattern formation. Even in the case of magnetic/\RAD (7 [IU) when writing a servo signal to the magnetic layer 5
The magnetic layer 5 can be made of a material with a very strong resistive force, such as a polymer compound or (such as photoresist TF etc.). The magnetic layer 3 is formed by polishing a thick layer of Ni.The magnetic layer 3 is formed by, for example, a plating method, and is made of a magnetic material made of Co, Ni, and P. In the case of coating, the buffer layer 4 can be omitted depending on the conditions.

In this way, a material with a sufficiently high coercive force for the magnetic layer 5 can be selected, and the magnetic layer 5 can be made up of fragments of a magnetic material with a magnetization of 1. ., it is almost impossible to think that the topo signal will be degraded by the write magnetic field when recording data.

Figure 2 shows the uninvented first embodiment 0) Gas double layer medium [de (
1) A perspective view of the lower magnetic layer.The 6° servo track 9 is composed of the magnetic layer 11 that remains after removing the magnetic layer by an etching method. uniformly magnetized 12 sai 1, remaining magnetic layer 1
Magnetic flux leaks from the end face force 1 of 171. I'm about to go out.

The magnetization pattern of the remaining one orthogonal layer 11 (the magnetization pattern is such that a signal is generated at a frequency sufficiently lower than the lowest frequency included in the data signal, and there is no harmonic relationship between adjacent servo tracks 9). It is assumed that the magnetization pattern of the remaining magnetic layer 11 is selected so that a low frequency signal is generated.

In this embodiment, a data track of a partial magnetic layer having a track center on the boundary line of the adjacent servo track 9 records a data signal, and the data track of the adjacent servo track 9
(Also, two 4f low frequency signals are generated alternately in a harmonic relationship with each other.
The two types of servo signals of the photo track 9 and the data signal of the data track above it are read out simultaneously using a magnetic field, and two types of small signals are separated from the readout signal strength. By comparison, a magnetic/\rad position error signal is obtained, and the magnetic/\rad position can be aligned on a desired data track with high precision.

FIG. 3 is a perspective view of the lower magnetic layer of the magnetic double layer recording medium according to the second embodiment of the present invention. The servo track 13 is composed of a portion 15 from which the magnetic layer has been removed by an etching method and a residual magnetic layer J4, which is uniformly magnetized in the track direction (16) by a DC magnetic field, and the magnetic flux leaks from the end face of the remaining magnetic layer J4. A1. γS is set so that it appears.

In this embodiment, a servo signal similar to that in the first embodiment is generated, but since the area of the magnetic layer 14U) is larger than that of the first real sister 1'=11 and 111, it is less susceptible to the influence of vertical rise. Furthermore, it has the advantage of being less susceptible to the effects of magnetic fields for recording and reproduction.

The magnetization pattern shown in this embodiment is one that generates two types of frequency signals. , the present invention (not limited to example 77 i! There are various ways to do this.

Uninvented 10th) Effect J, *I Multi-cutting force - magnetization pattern across the bottom rack 0) Creation of a low-density pattern that generates servo signals by etching using a mask and applying direct current This eliminates the hassle of recording servo signals magnetically and radially every time.
Furthermore, it is possible to produce magnetic double layer media with the same magnetization pattern in large quantities using the same mask at low cost and with high precision. Since it is used for recording (direct current (magnetization is applied by applying one field) and magnetization of turns is performed to obtain a servo signal, the magnetic material that forms the magnetization pattern is made of a material with a very high resistance to 6 light Q). The servo signal deteriorates (almost 1x).

The third C/) effect is formed by removing the magnetization pattern by etching the ta-based material υ), and is magnetized in one direction, so it is strong both magnetically and structurally.

In the present invention (in other words, the upper and lower magnetic layers O), of which the magnetic layer F is etched and a uniform direct current field σ] is applied, magnetization no-turns that generate servo signals are formed, and the lower magnetic layer is Since a magnetic double layer recording medium that records data signals on the layer 6 has been obtained, the servo signal and the data signal are read out at the same time (at the same time and read out at the same time, and each is separated to obtain the τ track position error signal and the desired υ). 1- By making the rack follow the magnetic field, it is possible to record and reproduce high recording density, high density, and high density, which has been a problem for a long time.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view parallel to the recording direction of the medium of the 10th embodiment of the uninvented magnetic double layer recording medium, and FIG. 2 is the magnetic 4-double layer medium of the uninvented first embodiment. FIG. 3 is a perspective view of the lower magnetic layer of the magnetic double layer recording medium according to the second embodiment of the present invention. ... solid-air double layer 1) recording medium, 2...
...Protective film, 3,5...Magnetic layer, 4...Buffer layer, 7...
...Leakage 16 bundles, death = ・−・−・Non-fertile substrate,
9・・・・・・・・・-1+-Hol-7tsuk, 10.15・
...f'+lj after removing the magnetic layer, 11.14.
...7 remaining. : 1II (indicates the sexual strata) 30 Procedural amendment (spontaneous) Director General of the Patent Office ■, Indication of the case 1982 Special n"I Application No. 1
No. 83219 2, Title of invention Magnetic double layer recording medium 3
, Relationship to the case of the person making the amendment Applicant: 33-1 (423), Shiba 5, Minato-ku, Tokyo NEC Corporation Representative: Tadahiro Sekimoto 4, Agent 5, Drawing subject to amendment 6, Amendment Content drawings Figures 1, 2, and 3 have been revised as attached. (At the time of filing, the drawings in Japanese Patent Application No. 57-193171 and the drawings in the present application were mistakenly replaced.) 1I6 qtzqtott ll t

Claims (1)

[Claims] Consisting of two magnetic layers, upper and lower, the upper rR magnetic layer records data information in the form of tracks, and is formed on the lower magnetic layer, which has a larger drag force than the upper magnetic layer. In this magnetic recording medium ζ in which the positional information of the data track of the upper magnetic layer is obtained, nlJ
l The lower layer below is partially etched by etching (obtained by removing the magnetic material, and is uniformly magnetized by 1 force, and the upper magnetic layer U) track position. A magnetic double layer recording medium characterized in that the magnetization pattern is formed to generate information.