JPS63275050A - Information recording medium - Google Patents

Abstract

PURPOSE:To effectively connect a substrate and a spacer by storing a ring form burr formed on a disk substrate in a ring form burr storing groove disposed on the spacer. CONSTITUTION:The ring form burr 22 is formed on the surface of the substrate 21 and a recording layer 23 is provided on the surface to constitute the disk 24. The two disks 24 form bonding agent layers 27, 28 by internally placing the recording layer 23 through the ring form internal spacer 25 and the ring form external spacer 26 and are connected and the ring form burr 22 formed on the substrate 21 is stored in the ring form burr storing groove 29 provided in a position corresponding to the ring form burr 22 on a surface contacting the substrate 21 of the ring form internal spacer 25. Therefore, the burr is not an obstruction in connecting the substrate and the spacer.

Description

[Detailed description of the invention] [Field of invention] The present invention relates to an information recording medium.

More specifically, the present invention relates to an improvement in an information recording medium having an air sandwich structure.

[Technical Background of the Invention] In recent years, information recording media using high energy density beams such as laser beams have been developed and put into practical use. This information recording medium is called an optical disc, and includes video discs, audio discs, large-capacity still image files, and large-capacity computer discs.
A vine used as memory.

The basic structure of an optical disk is a disk-shaped transparent substrate made of a material such as plastic, and a recording layer provided thereon. The surface of the substrate on which the recording layer is provided is coated with an undercoat layer or an intermediate layer made of a polymeric material in order to improve the flatness of the substrate, improve the adhesion with the recording layer, and improve the sensitivity of the optical disc. It may be provided.

Various types of optical discs are known, but in recent years it has become common to use air sandwich structures in which the substrate is bonded with the recording layer on the inside via an inner and outer spacer. . Conventionally, an optical disk having an air sandwich structure is assembled by bonding an inner spacer and an outer spacer to a disk substrate using an adhesive, particularly an ultraviolet curable adhesive.

Generally, disk substrates are prepared by molding synthetic resin. There are compression molding methods, injection molding methods, injection-compression molding methods, and 22 methods as methods for molding disk substrates. It is done by filling. Injection molding is currently a commonly used method for molding disk substrates.

Several metal fittings are installed in the through hole in the center of the stamper on the side where the stamper is installed in the mold, but there is a slight gap at the boundary between the metal fittings. In the above method, when the mold is filled with resin material and the substrate is molded, the resin material gets into the gap between the recording area of the molded substrate and the periphery of the through hole in the center of the substrate (i.e. A ring-shaped burr with a height of 5 μm to 300 μm is formed in the portion located in the bonding region with the spacer.

When using a disk substrate having such burrs, there is a problem in that good bonding cannot be achieved when manufacturing information recording media. Here, with reference to the attached FIG. 1, problems with the air sandwich type information recording medium manufactured using a substrate with burrs as described above will be explained.

That is, in FIG. 1, a substrate 11 having a ring-shaped burr 12 formed on the surface of the substrate 11 is used. Also,
A recording layer 13 is provided on the surface of the substrate 11, forming a disk 14. Two disks 14 are placed together through a ring-shaped inner spacer 15 and a ring-shaped outer spacer 16, with the recording layer 13 inside, and the ring-shaped inner spacer 15
is an adhesive layer 17 , and the ring-shaped outer spacer 16 is bonded to the substrate 11 with an adhesive layer 18 . A ring-shaped burr 12 formed on the substrate 11 is in contact with the substrate 11.

When a ring-shaped burr 12 is formed at a position corresponding to the ring-shaped inner spacer 15 as shown in FIG. The thickness is greater than the thickness of the spacer joint 18'.

The manufactured information recording medium is then in a state where the thickness at the center is greater than the thickness at the outer periphery.

The thickness of the normal adhesive layer is 10 μm to 40 μm,
The height of the burr may be 100 μm or more. Since the height of the formed burr is not constant, there is a problem in that the thickness of the manufactured information recording medium is not constant, which causes a decrease in dimensional accuracy. Furthermore, there is also the problem that the presence of burrs prevents the spread of the adhesive, resulting in poor adhesion.

[Object of the Invention] An object of the present invention is to provide an information recording medium in which a substrate and a spacer are well bonded.

[Summary of the Invention] The inventor of the present application has discovered that an air sandwich type information recording medium in which disk substrates are pasted together via a spacer, and a disk substrate formed by filling a mold with resin, is used in injection molding. The present invention was completed by focusing on the fact that burrs are inevitably formed at certain positions on the disk substrate due to the mold structure, and that this is the cause of deterioration in dimensional accuracy.

The present invention provides a disc including a recording layer on the surface of a substrate having a ring-shaped burr formed on the surface, and a disc that may be provided with the recording layer, with the recording layer inside. An information recording medium joined through an inner ring pile spacer and a ring-shaped outer spacer, wherein a ring-shaped burr on a substrate is provided at a position corresponding to a ring-shaped burr on a surface of the spacer in contact with the substrate. The information recording medium is housed in a ring-shaped burr storage groove.

DETAILED DESCRIPTION OF THE INVENTION The invention will now be described in detail with reference to the accompanying drawings.

A typical embodiment of the information recording medium of the present invention is shown in FIG. That is, in FIG. 2, a ring-shaped burr 22 is formed on the surface of a substrate 21, and a recording layer 23 is provided on the surface of the substrate 21, forming a disk 24. The two disks 24 are joined together via a ring-shaped inner spacer 25 and a ring-shaped outer spacer 26, with the recording layer 23 facing inside, forming adhesive layers 27 and 28. Board 2! The ring-shaped burr 22 formed in the ring-shaped inner spacer 25 is accommodated in a ring-shaped burr accommodation groove 29 provided at a position corresponding to the ring-shaped burr 22 on the surface of the ring-shaped inner spacer 25 that contacts the substrate 21 . The ring-shaped burr storage groove 29 has a triangular cross section with a wide opening and a narrowed deepest part. The depth of the burr storage groove 29 is generally 5
Within the range of μm to 300 μm, preferably 30 μm
~100 μm. The width of the burr storage groove 29 is generally 5 mm.
Within the range of 0 μm to 5 mm, preferably 0.5 mm
~3mm.

Note that the above description describes preferred embodiments of the information recording medium of the present invention, and is not limited to the above embodiments. For example, the burr storage groove is provided to match the position of the burr formed on the substrate, but depending on the position of the burr, it may be located closer to the through hole in the center of the substrate or closer to the recording layer side. Alternatively, if burrs are formed at positions corresponding to the outer spacers of the substrate due to the structure of the mold, a burr accommodation groove may be provided in the outer spacers. The cross-sectional shape of the burr storage groove may be square, semicircular, U-shaped, or the like.

As the substrate, recording layer, and spacer constituting the information recording medium of the present invention, any known substrate, recording layer, and spacer can be used except for the parts that are characteristic of the present invention, and these will be briefly described below.

The material of the spacer provided with the ring-shaped burr accommodation groove, which is a feature of the present invention, is not particularly limited, and in addition to metal materials such as metal aluminum or aluminum alloy,
A thermoplastic resin material can be used. When using a metal material as a spacer, a ring-shaped burr accommodation groove may be provided by cutting the spacer at a position corresponding to the burr, or a ring-shaped protrusion that forms a burr accommodation groove in the mold in advance. The spacer may be cast by providing a spacer. Further, when a thermoplastic resin material is used as the spacer, a ring-shaped projection can be provided in the mold, and the spacer can be molded by filling the mold with the resin material.

The substrate used in the present invention can be arbitrarily selected from resin materials conventionally used as substrates for information recording media. Optical properties, flatness, processability of the substrate,
In terms of ease of handling, stability over time, and manufacturing cost,
Examples of substrate materials include acrylic resins such as cell cast polymethyl methacrylate and injection molded polymethyl methacrylate; vinyl chloride resins such as polyvinyl chloride and vinyl chloride copolymers; epoxy resins: and synthetic resin materials such as polycarbonate. It can be mentioned preferably.

Among these, preferred are polymethyl methacrylate, polycarbonate, and epoxy resin in terms of dimensional stability, transparency, and flatness.

The surface of the substrate on which the recording layer is provided has improved flatness,
An undercoat layer (and/or intermediate layer) may be provided for the purpose of improving adhesive strength and preventing deterioration of the recording layer.

Examples of materials for the undercoat layer (and/or intermediate layer) include polymeric substances such as polymethyl methacrylate, acrylic acid/methacrylic acid copolymers, nitrocellulose, polyethylene, polypropylene, polycarbonate, etc. organic substances: and inorganic oxides (
Si02, AfL, 03, etc.), inorganic fluoride (MgFz)
Inorganic substances such as

Examples of materials used for the recording layer include Te, Zn%
In% Sn% Zr, A1, Ti% Cu.

Examples include metals such as Ge and Au%Pt; semimetals such as Bi and As%Sb; semiconductors such as Si; and alloys thereof, or combinations thereof.

Compounds such as sulfides, oxides, borides, silicon compounds, carbides, and nitrides of these metals, semimetals, or semiconductors; and mixtures of these compounds and metals can also be used in the recording layer. Alternatively, combinations of dyes, dyes and polymers, and dyes and the aforementioned metals and metalloids can also be used.

The recording layer may further contain various known metals, semimetals, or compounds thereof as recording layer materials.

The recording layer can be formed on the substrate directly or via an undercoat layer by using the above-mentioned materials by vapor deposition, sputtering, ion blasting, coating, or the like. The recording layer may be a single layer or a multilayer, but its layer thickness is generally in the range of 100 to 5,500×, preferably in the range of 150 to 1,000×, in view of the optical density required for optical information recording.

Note that the surface of the substrate opposite to the side on which the recording layer is provided is coated with an inorganic substance such as silicon dioxide, tin oxide, or magnesium fluoride in order to improve scratch resistance and moisture resistance.
The f1 film made of a polymer material such as a thermoplastic resin or a photocurable resin may be provided by a method such as vacuum deposition, sputtering, or coating.

[Effects of the Invention] In the information recording medium of the present invention, the ring-shaped burr formed on the disk substrate is accommodated in the ring-shaped burr storage groove provided in the spacer, so that the burr is separated between the substrate and the spacer. Does not interfere with bonding. Therefore, the information recording medium of the present invention has a good bond between the spacer and the disk substrate, and has high dimensional accuracy.

[Brief explanation of the drawing]

′! FIG. J1 is a sectional view showing an example of the structure of the information recording medium of the present invention. 1! , 21: Substrate 12.22: Ring-shaped burr 13.23: Recording layer 14.24: Disk (substrate) 15.25: Inner spacer 16.26: Outer spacer 17.18.27.28: Adhesive layer 29: Ring-shaped burr storage groove

Claims (1)

[Claims] 1. A disk including a recording layer on the surface of a substrate having a ring-shaped burr formed on the surface, and a disk that may include a recording layer, with the recording layer inside,
An information recording medium joined via a ring-shaped inner spacer and a ring-shaped outer spacer, wherein a ring-shaped burr on a substrate is provided at a position corresponding to the ring-shaped burr on the substrate on a surface of the spacer that contacts the substrate. An information recording medium characterized in that the information recording medium is accommodated in a ring-shaped burr accommodation groove. 2. Both of the two disks have burrs and a recording layer, and each burr is accommodated in a ring-shaped burr-accommodating groove provided on both surfaces of the spacer that contact the respective substrates. An information recording medium according to claim 1. 3. 2. The information recording medium according to claim 1, wherein the ring-shaped groove has a triangular cross section with a wide opening and a narrow deepest part. 4. 2. The information recording medium according to claim 1, wherein the burr storage groove is provided on at least one of the inner spacer and the outer spacer. 5. The width of the opening in the cross section of the burr storage groove is 0.5 mm to 3 m.
2. The information recording medium according to claim 1, wherein the information recording medium has a depth of 30 μm to 100 μm.