JPS6344338A - Information recording medium disk of type to detect change of electrostatic capacity value - Google Patents

Abstract

PURPOSE:To obtain a disk which maintains high stability for a long period of time by sticking a thin metallic film onto the signal surface of a resin substrate on which information is recorded in the form of the changes of geometrical shapes and sticking and forming a thin carbonaceous film having high resistance thereon. CONSTITUTION:The signal surface having the bit arrays corresponding to the information signal to be recorded is formed on the substrate 1 made of; for example, polyether imide synthetic resin having excellent heat resistance, insulating characteristic, chemical resistance and moldability. The thin metallic film 2 is stuck and formed onto the signal surface of the substrate 1 and the thin carbonaceous film 3 having the high resistance is stuck and formed on the thin film 2, by which the information recording medium disk of the type to detect the change of the electrostatic capacity value is constituted. Since the thin film 3 is hard and has wear resistance, the damage of the disk is obviated even if a reproducing stylus traces the same part of the disk for a long period in a still image reproduction mode.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention is such that reproduction of an information signal recorded as a change in geometrical shape is performed by detecting a change in capacitance value. Regarding information recording medium discs.

(Prior Art) As is well known, the reading of information signals recorded on an information recording medium disc (hereinafter referred to as a disk) as changes in geometrical shape is performed using a capacitance value change detection reproducing needle (hereinafter referred to as a disk). In the capacitance change detection type recording and reproducing method, which is performed by detecting changes in capacitance using a reproducing needle (hereinafter referred to as a reproducing needle), the electrode of the reproducing needle used to read out information signals is extremely thin. Compared to disks that use light to read out information signals, they have the advantage of being easier to read out information signals due to a much smaller bit array.
Therefore, by using a resin that can effectively transfer minute pits from the standber and employing a molding method, it is possible to easily provide a disk capable of higher density recording.

Now, for a disc configured in such a way that the reproduction of information signals recorded as changes in geometrical shape is performed by detecting changes in capacitance value, the information signals transferred from the stamper and A thin metal film is deposited on the surface of a resin substrate on which a corresponding array pattern of protrusions and recesses is formed, and a dielectric thin film is deposited on the metal thin film.

Further, a structure in which a layer of lubricant such as silicone oil is provided on a thin film of a dielectric material is disclosed, for example, in Japanese Patent Application Laid-open No. 47-37415, and On the surface of a base material containing fine particles of a conductive material 5f (e.g. carbon or metal) microencapsulated by a coating of synthetic resin such as vinyl,
There is also a structure in which an array pattern of concave and convex portions corresponding to an information signal is transferred from a stamper, for example, in JP-A-53-1
No. 16104, Japanese Patent Application Laid-open No. 119017/1983,
JP-A-54-140518, JP-A-55-386
This is disclosed in Publication No. 99 and other known documents.

By the way, a thin metal film is deposited and formed on the surface of a resin substrate on which a concavo-convex array pattern corresponding to an information signal is formed on the surface of the disk of the former configuration described above, and also on the above-mentioned thin metal film. Reproduction of an information signal from a disk in which a thin dielectric film is applied to the disk and a layer of lubricant such as silicone oil is applied on the thin dielectric film causes a change in the capacitance value. Detection type regeneration needle (
What can be done with the playback needle (hereinafter referred to as the playback needle) in sliding contact with the thin film of the Mfd body on the disc is the electrode with a minute area provided on the playback needle and the unevenness that corresponds to the information signal on the disc. The electrostatic capacitance value between an electrode made of a thin metal film provided on the surface of a resin substrate with an array pattern formed on the surface changes in accordance with the array pattern of the unevenness corresponding to the information signal. This is because it can be extracted as a change in electrical quantity by a detection circuit connected to the electrode of the needle, and the disk of the latter configuration described above, that is, a conductive substance microencapsulated by a synthetic resin coating. The reproduction of the information signal from the disc has a configuration in which a concavo-convex array pattern corresponding to the information signal is transferred from the standber onto the surface of the base material, which is composed of fine particles, by sliding the reproduction needle onto the disc. What can be done in this state is the electrostatic capacitance between the small-area electrode provided on the regeneration needle and the electrode formed by the conductive layer formed by micro-encapsulated conductive material particles on the disk. This is because the change in the value according to the arrangement pattern of the unevenness corresponding to the information signal formed on the surface of the disk can be extracted as a change in the amount of electricity by the detection circuit connected to the electrode of the playback stylus. be.

Now, as is well known, the playback stylus is used in sliding contact with the disk surface that is rotating at high speed, so the playback stylus gradually wears out due to the sliding contact with the disk surface. In order to withstand long-term use, the recycled needle is made of a highly hard material with wear resistance, such as diamond or sapphire, and electrodes made of a conductive material are formed on the recycled needle body. something is being used.

In addition, as mentioned above, the surface of the disk that rotates at high speed with the recycled needle in sliding contact with it is made of a highly hard material with wear resistance, and its surface is not easily worn out by the sliding contact of the recycled needle. In this way, a disk is used in which the surface of the disk is coated with a lubricant.

That is, as for a disk configured with the surface of the disk coated with a thin layer of lubricant as described above, (1) a thin film of lubricant for improving surface lubricity may be applied to the surface of the disk using a spinner method or other suitable method. (2) A required amount of a lubricant for improving surface lubricity is added to the molding composition constituting the base material of the disc, and the surface of the molded disc is The lubricant for improving surface lubricity described above was allowed to ooze out little by little, and the oozing lubricant for improving surface lubricity formed a thin film of the lubricant for improving surface lubricity on the surface of the disk. , etc. have been in practical use for a long time.

(Problem to be Solved by the Invention) However, when the disk of the configuration type (1) described above is new, the thin layer of the lubricant for improving surface lubricity formed on the surface of the disk is Since it has a uniform thickness over the entire surface, it improves wear resistance, but problems may occur if a limited area is played for a long time. The lubricant for improving surface lubricity that is mixed into the molding composition that makes up the base material of the disk includes the molding composition that makes up the base material (polyvinyl chloride, carbon fine particles, etc.)
However, the amount of lubricant that oozes out from the inside of the molded disk to the surface is microscopically uniform over the entire surface of the disk. Therefore, the thin film of the lubricant for improving surface lubricity formed on the surface of the disk has a sliding contact surface of the regeneration needle (for example, the diagonal length is 7 to 8 μm).
In many cases, unevenness in the thickness occurs in units of a large area compared to the area of a rectangle (about rn), and this causes local variations in the wear resistance of the disc, making it difficult to It is absolutely inevitable that the parts of the disc with low wear resistance will be damaged during sliding contact with the disc, and discharge from the electrode of the regeneration needle will occur there, destroying the arrangement at pitch 1 on the No. 43 surface of the disc. In particular, during still image playback (still playback) in which the playback needle is repeatedly traced over the same recording trace, the problem is that the disk is seriously damaged.

In this way, conventional discs have a thin film of lubricant on their surface to improve surface lubricity to give the disc wear resistance, but it is not possible to repeatedly trace the same recorded trace with the playback needle. During still image playback (still playback)
In addition, the occurrence of damage to the disk became a problem, so the emergence of a disk that was free from the above-mentioned problems and had high stability over a long period of time was eagerly awaited.

(Means for Solving the Problems) The present invention involves forming a metal thin film on the surface of a resin substrate on which information is recorded as a change in geometrical shape, and The above-mentioned problems are solved by providing a capacitance change-detecting information recording medium disk on which a highly resistive carbonaceous thin film is adhered.

(Example) The attached drawing is a longitudinal cross-sectional side view of a part of the disk of the present invention, and in the drawing, 1 is a material having excellent heat resistance, insulation, chemical resistance, and moldability, such as polyetherimide resin. A signal surface having a bit arrangement corresponding to the information signal to be recorded is formed on one or both sides of the resin substrate 1.

Further, 2 is a metal thin film deposited on the signal surface on which the bit array of the information signal is formed in the substrate 1, and 3 is a high-resistance carbon film deposited on the metal thin film 2 described above. It is a thin film.

The metal thin film 2 described above adheres to the constituent material of the substrate 1 with strong adhesive force.

A metal material that adheres with strong adhesion to the constituent materials of the highly resistive carbonaceous thin film 3 formed on the metal thin film 2, such as nickel, titanium, hafnium, or any other suitable metal, Alternatively, a nickel-cobalt alloy or other suitable alloy may be deposited as a metal thin film 2 of a predetermined thickness on the substrate 1 on which the information signal bit array is formed as described above by means of sputtering. In addition, the high-resistance carbonaceous thin film 3 described above is
A high-resistivity carbonaceous thin film 3 having a predetermined thickness is deposited on the metal thin film 2 by sputtering in a state that exhibits a high resistance value.

Next, an example of a method for manufacturing the information recording medium disk (disk) of the capacitance value change detection type according to the present invention configured as described above will be described as follows. first,
By injection molding, for example, by supplying polyetherimide resin into an injection molding machine equipped with a stamper having a bit arrangement according to the information signal to be recorded.

A resin substrate 1 is made in which a bit arrangement based on an information signal formed on a standby is well transferred to a signal surface.

A resin substrate 1 made by injection molding as described above.
After degreasing it by normal degreasing means, the final vacuum level was reduced to 5X10-@Torr in a sputtering device.
, for example, by sputtering the constituent material of the metal thin film 2 using a target, for example a nickel target, in an argon atmosphere of 2×10 −2 Torr at a temperature of about 80° C.

L! of 500 angstroms to 1000 angstroms on the signal surface of the resin substrate 1 described above. ! A thick nickel thin film 2 is formed.

Next, with respect to the nickel thin film 2 deposited on the signal surface of the resin substrate 1 as described above.

After performing pretreatment as necessary, a highly resistive carbonaceous thin film is formed in a sputtering apparatus at an ultimate vacuum of 5XIO"'Torr, e.g., in an argon atmosphere of 2X10-"Torr at a temperature of about 80°C. 500 was made to exhibit a high electrical resistance value on the nickel thin film 2 deposited on the signal surface of the resin substrate 1 by sputtering using a graphite target used as the material of No. 3. Highly resistive carbonaceous thin VX with a film thickness of angstroms to 800 angstroms
3 is formed into a film.

As described above, on the signal surface of the resin substrate 1, a metal thin film 2 showing a pit arrangement corresponding to the pit arrangement according to the information signal on the signal surface of the resin substrate 1 and the metal thin film 2 are formed. A high-resistance carbonaceous thin rf showing pit arrays corresponding to information signal pit arrays on the surface of the thin 1lI2! X
A disk of the present invention having a structure in which 3 and 3 are stacked is obtained.

The reproduction of information signals from the disk of the present invention having the above-mentioned configuration is achieved by using a capacitance formed on the surface of the disk that is being rotated by 1ψ at a predetermined rotation rate and having a high electric resistance value and capacitance. This is done by bringing the sliding surface of the regeneration needle into sliding contact with the surface of the high-resistance carbon M thin 11!53 that functions as a dielectric layer during the regeneration operation based on value change detection. The carbonaceous thin film 3 on the surface of the disk in contact functions as a dielectric layer exhibiting an extremely high resistance value. The capacitance value between an electrode made of a 4t metal thin film 2 provided on the signal surface of a resin substrate 1 having a concavo-convex arrangement pattern corresponding to the signal number is formed on the signal surface.

A detection circuit connected to the electrode of the reproducing needle detects the state changing according to the arrangement pattern of the unevenness corresponding to the information signal as a change in the electric layer, and reproduces the signal.

In addition, since the highly resistive carbonaceous thin film 3 appearing on the surface of the disk is hard and wear-resistant as described above, the playback mode is set to still image playback mode, and the same portion of the disk is The disk is not damaged even if the playback needle is traced over a long period of time, and the highly resistive carbonaceous thin film 3 also functions as a good S retention film for the disk.

(Effects) As is clear from the detailed explanation above, a gold GC thin film is deposited and formed on the signal surface of a resin substrate on which information is recorded as changes in geometric shape. , Information recorder 8 of the capacitance value change detection type of the present invention, which is formed by depositing a highly resistive carbon thin film on the metal thin film described above.
The medium disk has a high-resistance carbonaceous thin film 3 with which the reproducing needle slides during the operation of reproducing information signals from the disk.
exists in a state that exhibits an extremely high resistance value and functions as a dielectric layer, so the micro-area electrode installed on the playback needle and the concave-convex arrangement pattern corresponding to the information number M on the disc are A state in which the capacitance value between the metal thin film 2 provided on the signal surface of the resin substrate 1 formed on the signal surface and the electrode is changing according to the arrangement pattern of concavities and convexities corresponding to the information signal. is well detected as a change in the amount of electricity by the detection circuit connected to the #i pole of the regeneration needle, and the above-mentioned high-resistance carbon thin film 3 is hard and wear-resistant. Even if the mode is set to still image playback mode and the playback needle traces the same part of the disk for a long period of time, the disk will not be damaged, and the high-resistance carbon thin film 3 described above provides good protection for the disk. The disc of the present invention has superior playback stability compared to the conventional discs mentioned above, and is also resistant to long-term use in the market and environmental changes. It also has stable information signal reproduction characteristics, and the discs of the present invention require fewer manufacturing steps because there is no need to provide a layer of lubricant such as silicone oil, which is required with conventional discs. The present invention also has the advantage that it is possible to easily provide a disk of good quality with a long life without the problems of conventional disks, and also,
As the resin for the disk substrate, a synthetic resin having excellent heat resistance, insulation, chemical resistance, and moldability, such as polyetherimide resin, is used.

If bits are transferred from a stamper by injection molding, it is possible to easily provide a disk in which pit arrays corresponding to information signals are formed at a higher density.

[Brief explanation of the drawing]

The accompanying drawing is a longitudinal sectional side view of a portion of the disc of the present invention. 1... Substrate, 2... Metal thin film, 3... Highly resistive carbonaceous thin film, Patent applicant: Japan Victor Co., Ltd. 2r゛

Claims (1)

[Claims] A thin metal film is deposited and formed on the signal surface of a resin substrate on which information is recorded as changes in geometric shape.
Further, an information recording medium disk of a capacitance value change detection type formed by adhering and forming a highly resistive carbonaceous thin film on the metal thin film described above.