JP2953205B2 - Tracking servo type information recording medium - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording medium of a tracking servo type or the like.

[0002]

2. Description of the Related Art In an information recording medium, an information signal recording area for recording an information signal, a servo information recording area for providing address information of a signal recorded in the information signal recording area and scanning guide information of a signal reading head Are provided. In recent years, there has been a strong tendency to increase the recording capacity of information signals, and various efforts have been made for that.
In order to increase the storage capacity while keeping the size of the desk constant, it is necessary to increase the recording density of information signals.

However, when the recording density is increased, there is a problem that the frequency of erroneous signals, that is, the error rate is increased due to the influence of the thermal expansion of the desk, and the influence of the distortion of the desk and the influence of uneven rotation are caused. Also raises the problem that the error rate increases.

Conventionally, a sector servo system has been frequently used as a servo form of an information recording medium. However, in this sector servo system, even if an attempt is made to increase the recording density, the above-mentioned problems are encountered and limitations arise. It is difficult to realize. Therefore, recently, a tracking servo system has been adopted, and research and development for increasing the recording density have been actively carried out. As an information recording medium of this tracking servo system, for example, as shown in FIG. 3, an information signal forming region 2 is formed of a magnetic material on the surface of a desk 1 and a magnetic material is similarly formed on the adjacent side via a buffer portion 3. Although the tracking signal forming region 4 is provided depending on the body, it can be seen that if both the information signal forming region 2 and the tracking signal forming region 4 are formed using a magnetic material, magnetic interference between the information signal and the tracking signal will inevitably occur. In order to avoid this, a wide buffer section 3 must be provided, which causes a problem that the recording density of the information signal cannot be increased so much.

For this reason, a method of forming the information signal forming area 2 and the tracking signal forming area 4 using recording means having different functions has been studied. For example, in FIG. The tracking signal forming region 4 is formed by using a body, and the tracking signal forming region 4 is formed by a concave and convex groove, and an electrostatic tracking servo system in which a capacitance change of the concave and convex groove is detected by an electrostatic sensor, or as shown in FIG. The information signal forming area 2 is formed of a magnetic material, a tracking signal forming area 4 is formed between the information signal forming areas 2 in the form of a hole, and a tracking signal is read from the hole by an optical sensor. Has been proposed.

[0006]

However, in the electrostatic tracking servo system, although the width of the buffer section 3 can be made very small, the information signal forming area 2 and the tracking signal forming area 4 are formed on the same plane. Must be
It is still insufficient to dramatically increase the recording density of information signals.

In the optical tracking servo system, the information signal forming region 2 and the tracking signal forming region 4 must be formed on the same surface, and therefore have the same problem. If it is applied, dust or the like adheres and accumulates at the edge of the hole, which causes a problem in reliability of signal reading.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a highly reliable information recording medium having a remarkably increased information signal recording capacity and an extremely low error rate. Is to provide.

[0009]

The present invention is configured as follows to achieve the above object. That is, the tracking servo type information recording medium of the present invention is plastic
A magnetic signal layer on which information signals are placed is formed on the base surface of the desk, and the surface is flat on the magnetic signal layer.
A dielectric signal layer is provided, and the dielectric signal layer
Signs or concentric tones formed by ion implantation
A racking signal is provided, and the magnetic signal layer is
Ground for tracking signal detection of the dielectric signal layer
It is characterized by being configured as a surface .

[0010]

[Function] A magnetic signal layer and a dielectric signal layer are three-dimensionally arranged and formed on a base of a desk, and a tracking signal formed on the dielectric signal layer by a read head utilizes a change in capacitance. The information signal of the magnetic material signal layer is read out using a magnetic change.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a main configuration of an embodiment of an information recording medium according to the present invention, and FIG. 2 shows a cross-sectional configuration thereof. In these figures, a magnetic material signal layer 6 of a magnetic material is formed on the entire surface of the desk 1 made of a disc-shaped plastic plate using a known film forming means such as sputtering or vapor deposition. The information signal 11 is supplied to the magnetic signal layer 6.

The desk 1 on which the magnetic signal layer 6 is formed
The surface of the magnetic material signal layer 6 is flattened if necessary.
A film of the intermediate layer 7 is formed on the surface of the substrate with a flat surface . This intermediate layer 7 functions as the dielectric signal layer 5, and the tracking signal 12 is supplied to the dielectric signal layer 5.

The dielectric signal layer 5 is formed of the magnetic signal layer 6
The dielectric constant of different dielectric constant materials, for example those formed by the film, such as aluminum oxide or aluminum nitride, acid in accordance with the address codes on the surface of the dielectric signal layer 5
The oxide film is formed in a code or concentric manner by an ion implantation method, or provided on the surface of the dielectric signal layer 5 by forming a nitride film in a code or concentric manner by an ion implantation method in accordance with the address code. The tracking signal 12 is supplied to the dielectric signal layer 5. Therefore, the dielectric signal layer 5 and the magnetic signal layer 6 are formed three-dimensionally on the desk 1.

In this embodiment, when a tracking signal is read, the magnetic signal layer 6 on the surface of the desk 1 is electrically grounded. If necessary, a protective film 8 such as a lubricating layer or a smoothing layer is formed on the surface of the dielectric signal layer 5, and a protective means used in a well-known recording medium such as preventing adsorption of a signal head is also used. That need not be mentioned here.

According to this embodiment, since the magnetic signal layer 6 and the dielectric signal layer 5 are vertically arranged three-dimensionally with respect to the base of the desk 1, the magnetic signal layer 6 extends over the entire surface of the desk 1. 6, the recording capacity of the information signal can be dramatically increased. In the information recording medium having the configuration of the present embodiment, it is possible to record information of 1 GB or more on the 3.5-inch desk 1.
Compared with the fact that an inch desk can only record information of several tens of Mbytes, it can be seen how large the information recording medium of this embodiment can record an information signal.

The tracking signal is supplied to the dielectric signal layer 5.
Is detected and read as a change in capacitance. Therefore, even if the dielectric signal layer 5 and the magnetic signal layer 6 are vertically arranged three-dimensionally with respect to the base of the desk 1, there is a problem particularly in reading. And the tracking signal and the information signal are detected completely independently of each other, and since there is no tracking signal hole form on the surface of the desk 1 as in the conventional example, there is no possibility that dust and dirt adhere and accumulate. Therefore, the tracking signal can be read without being affected by dust or the like, so that the reliability of the signal reading can be greatly improved. As a result of examining this effect, the error rate was at most about 10-6 in the conventional example, but in the present embodiment, the error rate was as much as 10-9, and the reliability was dramatically improved.

Further, in this embodiment, since the plastic desk 1 is used without using a metal desk , the material cost can be reduced, and a high-performance information recording medium can be provided at a low cost. It becomes possible.

In addition, since the magnetic signal layer 6 is formed on the desk 1 made of a plastic plate and the dielectric signal layer 5 is formed on the magnetic signal layer 6, a problem arises when a plastic desk is used. It is possible to manufacture a high-quality information recording medium by eliminating the following disadvantages. For example, as shown in FIG. 5, when a desk 1 made of a plastic plate is used, the lower surface 14 is used as a ground plane. However, if the dielectric signal layer 5 is formed directly on the desk 1, the plastic plate becomes a certain thickness. Since it is difficult to manufacture, there is a possibility that thickness variation is apt to occur, and the capacitance changes in response to the thickness variation of the plastic plate, and there is a possibility that the tracking signal cannot be read accurately. However, in the present embodiment, as described above, the desk 1
A magnetic signal layer 6 is formed thereon, and the magnetic signal layer 6 is used as ground (that is, tracking of the dielectric signal layer).
(The ground surface for signal detection is used.) Even if there is unevenness 13 on the bottom surface 14 of the desk 1, a film having no thickness variation of the magnetic signal layer 6 functions as the ground. It is completely unaffected by the changes. Therefore, the tracking signal can be read accurately, and the reliability of the signal reading can be greatly improved.

The present invention is not limited to the above embodiments, but can take various embodiments. For example, in the above embodiment, the disc-shaped desk 1 is used, but the desk 1 may be a cylindrical desk.

[0020]

According to the present invention, the dielectric signal layer on which the tracking signal is formed and the magnetic signal layer on which the information signal is formed are three-dimensionally arranged vertically with respect to the base of the desk. Since the magnetic signal layer can be formed over the entire plane area of the desk, the recording capacity of the information signal can be significantly increased.

Further , since the tracking signal is read by detecting the dielectric signal layer as a change in capacitance, there is no interference with the magnetic signal layer, and the influence of dirt and dust adhering to the desk surface is eliminated. Since the detection can be performed without receiving the information, the reliability of information reading can be remarkably improved. Further, according to the present invention, the magnetic material signal layer
Ground plane for tracking signal detection of dielectric signal layer
When using a plastic desk
Can solve the following disadvantages
A high-quality information record using a plastic desk.
Recording media can be provided at low cost. That is,
When using a plastic desk, the bottom surface
Was used as the ground plane, but the plastic plate
Because it is difficult to produce a constant thickness,
Easy to occur, so this plastic desk
When the dielectric signal layer is formed directly, the thickness of the plastic
The capacitance changes in response to the fluctuation,
May not be able to read the
You. However, according to the present invention, as described above,
A magnetic material signal layer is formed on the
Layer to ground for tracking signal detection of dielectric signal layer
Surface, so even if there are irregularities on the bottom of the desk
Even when the thickness of the magnetic signal layer does not fluctuate,
Since it functions as a surface, the shadow of the change in capacitance due to unevenness
It is not affected at all. Therefore, tracking
Signal reading can be performed accurately, and signal reading
High quality information that can greatly increase the reliability of
The information recording medium can be provided using a plastic desk,
Providing such high-quality information recording media at low cost
Can be.

[Brief description of the drawings]

FIG. 1 is a main part configuration diagram of an embodiment of an information recording medium according to the present invention.

FIG. 2 is a cross-sectional configuration diagram of FIG.

FIG. 3 is an explanatory diagram of a conventional electrostatic or magnetic tracking servo type information recording medium.

FIG. 4 is an explanatory diagram of a conventional information recording medium of an optical tracking servo system.

FIG. 5 is an explanatory diagram of an information recording medium in which a dielectric signal layer 5 is formed on the surface of a desk 1 made of a plastic plate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Desk 3 Buffer part 5 Dielectric signal layer 6 Magnetic signal layer

Claims (1)

(57) [Claims] 1. A magnetic signal layer installed an information signal to the base surface of the plastic desk is formed, the surface on the upper side of the magnetic signal layer is provided with a flat-shaped dielectric signal layer, dielectric Signed into the body signal layer by ion implantation
Or a concentric tracking signal is installed
Wherein the magnetic signal layer is tracked by the dielectric signal layer.
A tracking servo type information recording medium configured as a ground plane for detecting a tracking signal .