JPS60143459A - High-density recording medium for information signal and its production - Google Patents

Abstract

PURPOSE:To provide a titled medium with strong resistance to physical and chamical changes and to reduce cost with the decreased stages of production process by disposing the non-conductive material film side faces of films provided with semiconductor matgerial films on the surfaces of a disc substrate and heating and pressing the same to form geometrically shaped patterns on the semiconductor material films. CONSTITUTION:A film 1a consisting of a thermoplastic resin such as polycarbonate or the like and having a prescribed thickness is prepd. and a semiconductor film 2 consisting of a semiconductor material such as indium oxide and having a prescribed thickness is formed by a PVD means on one surface of the film 1a. The films 1a provided with the films 2 are disposed on, for example, both sides of a substrate body 1b having a prescribed thickness in such a way that both sides of the film 1a face each other. When dies 3a, 3b having projecting parts corresponding to recording signals are pressed thereto under heating from both sides, the video disc of an electrostatic capacity type is manufactured. The eletrostatic capacity changing according to the shape of rugged pits is detected and the prescribed information signals are exactly reproduced by the above-mentioned above-mentioned constitution. The need for providing a protective film is eliminated and the disc is highly durable. The production is simple and the cost is reduced.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a high-density information signal recording medium and a method for manufacturing the same.
In particular, when an information signal is recorded as a change in the geometrical shape of the front surface, such as a video disc or a digital audio disc, the back surface of the disc may be recorded. This invention relates to a capacitance type high-density information signal recording medium in which an information signal is reproduced by changing the capacitance between snoring volume ≦ in accordance with changes in geometric shape, and a method for manufacturing the same. .

[Conventional technology and problems]

Conventionally, pits are formed spirally or concentrically in a plane or groove according to an information signal, and the information signal is recorded as a change in geometrical shape to obtain an information signal recording medium. A playback needle made of diamond or the like with an electrode provided on the recording track is relatively scanned, and the capacitance formed between the electrode of the playback needle and the information signal recording medium changes according to the change in the geometrical shape. There is a so-called electrostatic capacitance reproduction method that reproduces recorded information signals by utilizing changes in the magnetic field.

A capacitive information signal recording medium used in this type of capacitance reproduction method has, for example, a capacitive capacitance between the surface of the recording medium body, which is press-molded with a geometrical change, and the electrode of the reproduction needle. For example, a thin metal film with several hundred holes is attached as an electrode to form a thin metal film, and on top of that, a thin metal film with several hundred holes is attached to protect the thin metal film, prevent short circuits between electrodes, and increase the dielectric constant between the electrodes. A recording medium with a structure in which a dielectric thin film is attached has been proposed, but recording media with this type of structure require many manufacturing processes, such as a press molding process for the recording medium body, a process for attaching a metal thin film, and a process for attaching a dielectric thin film. However, there are drawbacks such as complicated and troublesome manufacturing, requiring expensive and expensive manufacturing equipment, and extremely high manufacturing costs.

In addition, since the metal thin film or the like is provided after the recording medium body is press-molded with a geometric shape change,
There is a risk that the signal pattern may change, and there is a risk that the accuracy of the recorded information signal may decrease.Furthermore, there are drawbacks such as difficulty in controlling the thickness of thin films such as metal thin films and dielectric thin films.

[Means for solving problems]

Signals in a geometric pattern are formed on a disk base having a film made of a semiconductor material such as ITO, In2O3, SnO, etc. on the surface thereof.

The method for manufacturing such a recording medium is to provide a film made of a semiconductor material on the surface of the film, place the non-semiconductor material film side of the film with the semiconductor material film against the disk substrate surface, and then This method involves applying heat and pressure to form a geometrical pattern on a semiconductor material film.

〔Example〕

FIG. 1 is a partial explanatory diagram of an embodiment of a high-density information signal recording medium according to the present invention.

In the figure, 1 is a substrate of a predetermined thickness made of a predetermined resin or the like (h'), and 2 is a substrate such as ITO1In203, S
The semiconductor film is a semiconductor layer made of a semiconductor material such as nO2, preferably an oxide-based semiconductor material.

The thickness of the semiconductor film 2 is approximately 200 to 1000^ so that the surface resistance per unit area is 1000Ω or less, and is approximately 500λ when indium oxide is used, for example.

Further, on the surface of the semiconductor film 2, uneven pits are formed as shown in the figure, which are geometric patterns corresponding to signals reproduced by the capacitance reproduction method.

The capacitance-type high-density information signal recording medium configured as described above detects the capacitance that changes depending on the shape of the uneven pits, and accurately reproduces a predetermined information signal. Since it is a semiconductor film, it can effectively prevent damage to the regenerated needle electrode due to discharge, etc. Furthermore, when an oxide-based material is used as the material for the semiconductor film, this can cause physical and chemical damage. Since it is resistant to physical changes, it is unnecessary to provide a protective film and it is highly durable.

Also, since no protective film is required, manufacturing is simple and can be done at low cost.

Note that the substrate 1 may be made of a non-conductive material or a conductive material that does not contain as much carbon black as is required for the capacitance regeneration method.

FIGS. 2a, b, and c show high-density information signal equipment P according to the present invention.
First, as shown in Figure 2a, a thermoplastic resin such as polycarbonate with a thickness of about 20 to 2
A film 1a having a thickness of 00 μm is prepared, and a semiconductor film 2 made of a semiconductor material such as indium oxide and having a thickness of approximately 200 to 1000 λ is formed on one surface of the film 1a by PVD such as vapor deposition.

Next, as shown in FIG. 2, the semiconductor film 2-attached film 1a is placed on both sides of the substrate body 1b having a predetermined thickness so that the surface of the film 1a faces each other, and a convex portion corresponding to the recording signal is formed. A mold 3a having a mold 3a.

By heating and compression molding 3b from both sides, a capacitive video disc as shown in FIG. 1 is produced.

Or, as shown in FIG. 2C, a film 1a with a semiconductor film 2
Alternatively, a laminate with the film side thereof adhered to the substrate main body 1b in advance may be placed between the molds 3a and 3b and subjected to heat compression molding.

However, if the above process is adopted, the board body 1
Regarding the selection of materials for b and film 1a, film 1a
It is desirable that the glass transition point of the substrate body 1b be at least 10°C higher than that of the substrate body 1b.In other words, if this relationship is not satisfied, the semiconductor film 2 is likely to crack during hot compression molding, resulting in defective products. Easy to do.

Further, although the thickness of the substrate body 1b is approximately determined by the thickness of the intended recording medium, it is desirable that the thickness of the film 1a is approximately 20 μm or more.

That is, if the thickness of the film 1a is too thin,
This is because air enters between the film 1a and the substrate body 1b during hot compression molding, creating unnecessary unevenness and making it easy to produce defective products.

Similarly, a silicone oil film having a thickness of about 50 OA or less may be provided on the surface of the semiconductor film in order to protect the surface of the semiconductor film, provide peelability from the stamper, and lubricity between the semiconductor film and the regeneration needle.

〔effect〕

Since the disk base is simply provided with a semiconductor layer on the substrate, it can be done extremely simply and at low cost.

Furthermore, adverse effects on discharge, other physical changes, and chemical changes are less likely to occur.

Moreover, the manufacturing process is very simple and requires few steps.

[Brief explanation of the drawing]

FIG. 1 and FIGS. 2a, b, and c are explanatory diagrams of a high-density information signal recording medium and manufacturing process according to the present invention. 1...Substrate, 1a...Film (part of the board), 1b
. . . Substrate body, 2 . . . Semiconductor film. Patent applicant: Victor Japan Co., Ltd.

Claims (1)

[Claims] (1) A high-density information signal recording medium in which signals in a geometrical pattern are formed on a disk substrate having a semiconductor layer on its surface. ■ A semiconductor layer is provided on the surface of the film, the non-semiconductor layer side of the film with the semiconductor layer is placed against the surface of the disk substrate, and this is heated and pressed to form a signal with a geometric pattern on the semiconductor layer. A method for manufacturing a high-density information signal recording medium, characterized by: