JPS63152071A - Information recording medium - Google Patents

Abstract

PURPOSE:To facilitate insertion of a spindle to the spindle insertion hole of an information recording medium by chamfering the end part of an internal wall on the entrance side of the spindle insertion hole of a magnetism sensing hub. CONSTITUTION:The information recording medium is constituted with an information recording disk 10 and the sensing magnetic hub 20 and has a construction where the sensing magnetic hub 20 is installed in a transmission hole part in the center of the information recording disk 10. The sensing magnetic hub 20 has the construction where a magnetism sensing piece 24 is installed in the magnetism sensing hub main body 21 and has the spindle insertion hole 25 in the center of it and a chamfering part 22 is provided in the end part of the internal wall on the entrance side of the spindle insertion hole. The magnetism sensing hub 20 includes a projection which is inserted into the inside of the transmission hole 13 of the information recording disk 10 and the chamfering part 23 is provided in the upper end part of the periphery of the projection. Thus, the fixing operation to the spindle and the detaching operation from the spindle in the driving part of a player can be facilitated.

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 improvements related to a magnetically sensitive hub of an information recording medium provided with a magnetically sensitive hub.

[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 disk, and is
It can be used as a disc, an audio disc, a large-capacity still image file, and a large-capacity computer disk Φ memory.

The basic structure of an optical disk is a disc-shaped transparent substrate made of plastic, glass, or the like, and a recording layer provided thereon. The surface of the substrate on which the recording layer is provided is usually coated with an undercoat layer or an intermediate layer made of a polymeric material in order to improve the flatness of the substrate, the adhesive force with the recording layer, and the sensitivity of the optical disc. is provided.

A commonly used optical disc has a through hole in the center thereof into which a spindle for rotationally driving the optical disc is inserted. Recording (writing) of information on an optical disc is sometimes performed at the same time as forming the recording layer.
Alternatively, information may be written by irradiating the recording layer with a laser beam while rotating the manufactured optical disc. On the other hand, information recorded on an optical disc is reproduced (read) by rotating the optical disc and irradiating the recording layer with a laser beam having lower energy than the writing laser.

When recording or reproducing information while rotating an optical disc as described above, the optical disc needs to rotate with high precision without eccentricity or wobbling. The optical disc is equipped with a spindle, which is the center of rotation of the optical disc, and a clamp for fixing the optical disc on a rotary disk such as a player.

A commonly used method for fixing an optical disc to a rotary disc of a player is to use a spring to hold down the portion of the optical disc around the through hole where the recording layer is not provided.

In recent years, another method for fixing optical discs has been to attach a magnetically sensitive hub with a spindle insertion hole to a through hole in the center of a disc consisting of a recording layer and a substrate.
A so-called magnet fixing method has been proposed in which a magnetically sensitive hub is magnetically fixed using a magnetic material arranged on a rotary disk, etc.

Currently, the International Optical Disk Standardization Plenary Group 1 (ISO) is considering a unified standard for the magnetic fixing method for optical disks.

[Object of the Invention] An object of the present invention is to provide an improved information recording medium suitable for use in a magnetic fixing method.

Particularly, an object of the present invention is to provide an information recording medium equipped with a magnetically sensitive hub in which the drive unit of a player can be easily fixed to the spindle and detached from the spindle. be.

[Summary of the Invention] The present invention includes a through hole in the center. An information recording medium comprising a magnetically sensitive hub having a spindle insertion hole in the center attached to a through hole of an information recording disk on which information can be written and/or read by a laser, the hub having a spindle insertion hole. The information recording medium is characterized in that the end of the inner wall on the entrance side is chamfered.

Note that the magnetically sensitive hub preferably includes a protrusion that is inserted into the through hole of the information recording disk.

[Effects of the Invention] In the information recording medium of the present invention, since the inner wall end on the entrance side of the spindle insertion hole of the magnetically sensitive hub is chamfered, it is easy to insert the spindle into the spindle insertion hole of the information recording medium. This makes it easier to secure the player to the drive unit.

Furthermore, it is possible to easily remove the information recording medium from the drive section of the player.

In addition, when the magnetically sensitive hub includes a protrusion that is inserted into the through hole of the information recording disk, the upper edge of the periphery of the protrusion is chamfered, so that it is difficult to insert the magnetically sensitive hub into the through hole of the information recording disk. This makes it easier to attach the magnetically sensitive hub to the information recording disk during manufacturing.

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

The information recording medium of the present invention has a configuration as shown in FIG. 1, for example.

That is, the information recording medium of the present invention basically consists of an information recording disk 10 and a magnetically sensitive hub 20, and has a configuration in which the magnetically sensitive hub 20 is attached to a central through-hole of the information recording disk IO. .

A top view of the magnetically sensitive hub 20 shown in FIG. 1 is shown in FIG. 2, and a bottom view of the magnetically sensitive hub 20 is shown in FIG. 3.

The information recording disk 10 has a recording layer 12 provided on a substrate 11.

The magnetically sensitive hub 20 has a magnetically sensitive piece 24 on a magnetically sensitive hub body 21.
It has a spindle insertion hole 25 in the center, and a chamfered portion 22 is provided at the end of the inner wall on the entrance side of the spindle insertion hole.

The magnetically sensitive hub 20 shown in FIG. 1 includes a protrusion that is inserted into the through hole 13 of the information recording disk 10, and a chamfered portion 23 is provided at the upper end of the periphery of the protrusion.

The information recording medium shown in Figure 1.2.3 is an example of the configuration of the information recording medium according to the present invention, and the information recording medium of the present invention is not limited to the above configuration. It may be a mating type or an air sandwich type.

The substrate used in the present invention can be arbitrarily selected from various materials conventionally used as substrates for information recording media. Examples of substrate materials include glass such as soda lime glass in terms of optical properties, flatness, processability, handling, stability over time, and manufacturing costs.
Examples 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 polycarbonates. Among these, from the viewpoint of dimensional stability, transparency and flatness, polymethyl methacrylate,
Polycarbonate, epoxy resin and glass.

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, and polycarbonate; silane coupling agents, etc. Organic substances: and inorganic oxides (
Examples include inorganic substances such as Si02°A203) and inorganic fluorides (MgF2).

Examples of materials used for the recording layer include Te, Zn, I
n, Sn, Zr, An, Ti, Cu.

Examples include metals such as Ge, Au, and Pt; semimetals such as Bi, As, and 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, a combination of Dye 1 and a polymer, or a dye and the metal or metalloid listed above 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 using the above-mentioned materials directly on the substrate or via an undercoat layer by a method such as vapor deposition, sputtering, or ion blasting. 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 iso to 1,000, in view of the optical density required for optical information recording.

On the recording layer, for the purpose of improving mechanical strength, for example, natural polymeric substances such as gelatin and gelatin derivatives; synthetic materials such as cellulose derivatives, polysaccharides, latex-like vinyl polymers, and ethylene/vinyl acetate copolymers are used. A protective film made of a polymeric substance or the like may be provided.

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

Next, the magnetically sensitive hub attached to the information recording disk will be explained.

Examples of the material for the magnetically sensitive hub body include synthetic resins such as polycarbonate resin, polyacrylic resin, and acetal resin.

In order to match the thermal expansion coefficient and hygroscopic expansion coefficient of the substrate and the magnetically sensitive hub, it is preferable to use the same material for the magnetically sensitive hub body as the substrate material.

The magnetically sensitive material is made of a magnetically sensitive material such as iron or an alloy containing iron, but is preferably made of a material that is resistant to rust.The shape of the magnetically sensitive material is not particularly limited, but typical forms include: These include two types: magnetically sensitive powder in the form of a magnetically sensitive material in the form of powder, and magnetically sensitive pieces in the form of the magnetically sensitive material in the form of a plate, rod, or the like.

In addition, when using a magnetically sensitive piece, in order to prevent the magnetically sensitive piece from peeling off from the magnetically sensitive hub due to the stress caused by thermal expansion, a notch is made in the magnetically sensitive piece to disperse the stress caused by thermal expansion. For the same reason, a ring-shaped spring may be used as the magnetically sensitive piece.

The magnetically sensitive powder can be mixed into a magnetically sensitive hub body and injection molded to produce a magnetically sensitive hub. Further, a magnetically sensitive hub may be manufactured by embedding a plate-shaped magnetically sensitive piece in a magnetically sensitive hub body, or a magnetically sensitive piece coated with resin may be joined to the magnetically sensitive hub body.

Various known adhesives can be used to attach the magnetically sensitive hub to the information recording disk, and solvent-free adhesives, such as epoxy adhesives, UV-curing adhesives, UV-curing epoxy adhesives, and UV It is preferable to use a curable en-thiol adhesive, urethane adhesive, silicone adhesive, acrylic adhesive, hot melt adhesive, etc. Also, the attachment of the magnetically sensitive hub to the information recording disk can be performed using ultrasonic waves. This can be done by melting and bonding a part of the substrate or hub material. Alternatively, attachment by mechanical fastening is also possible.

As described above, the information recording medium of the present invention can be manufactured by attaching the magnetically sensitive hub, which is a feature of the present invention, to the central through hole of the information recording disk made of the above-mentioned substrate and recording layer. .

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the central portion showing the structure of an information recording medium according to the present invention. 2 is a plan view of the magnetically sensitive hub in FIG. 1; FIG. FIG. 3 is a bottom view of the magnetically sensitive hub in FIG. 1. 102 Information recording disk 11: Substrate 12: Recording layer 13: Through hole 20: Magnetically sensitive hub 21: Magnetically sensitive hub body 22: Chamfered portion 23: Chamfered portion 24: Magnetically sensitive piece 25 Spindle insertion hole

Claims (1)

[Claims] 1. A magnetically sensitive hub having a hole for inserting a spindle in the center is attached to an information recording disk having a hole in the center and capable of writing and/or reading information using a laser. 1. An information recording medium characterized in that an inner wall end on the entrance side of a spindle insertion hole of the hub is chamfered. 2. The information recording medium according to claim 1, wherein the magnetically sensitive hub includes a protrusion that is inserted into the through hole of the information recording disk, and the upper edge of the periphery of the protrusion is chamfered. .