JPS63173289A - Information recording medium - Google Patents

Abstract

PURPOSE:To maintain satisfactory rotation driving by installing a magnetic sensitive material to the surface of a hub, in a state that a separation from the hub of the magnetic sensitive material has been prevented by a projection having a bulged part in the end part provided on the surface of the hub. CONSTITUTION:The titled medium consists of an information recording disk 10 and a magnetic sensitive hub 20, and constituted so that the sensitive magnetic sensitive hub 20 is installed to a through-hole part of the center of the information recording disk 10. A magnetic sensitive material 22 is formed by a ring shape having a through-hole for allowing a spindle to pass through the center, and on its surface, a through-hole to be engaged to a projection is formed so as to become a point symmetry to the through-hole. The magnetic sensitive body 22 is installed to the surface of the hub 20 in a state that it has been prevented to be separated from the hub 20, by bulged part 24 of the end part of the projection provided on the surface of the hub 20.

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 includes video disks, audio disks, large-capacity still image files, and large-capacity computer disks.
It can be used as 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. On the surface of the substrate on which the recording layer is provided,
In order to improve the flatness of the substrate, improve the adhesion to the recording layer, or improve the sensitivity of the optical disc, an undercoat layer or intermediate layer made of a polymeric substance may be 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, the reproduction of information recorded on an optical disc (
Reading) is performed by irradiating the recording layer with a laser beam of lower energy than the writing laser while rotating the optical disc.

When recording information or producing FLR while rotating an optical disc as described above, the optical disc needs to rotate with high precision without eccentricity or wobbling. The device includes
It is equipped with a spindle, which is the center of rotation of the optical disc, and a clamp, etc., 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 of fixing optical discs is to use a through hole in the center of the disc, which consists of a recording layer and a substrate.

A so-called magnet that has a spindle insertion hole, a hub equipped with a magnetically sensitive material (magnetic hub), and the magnetic material placed on the player's drive ff1 (rotary disk, etc.) magnetically fixes the magnetic hub. A fixing method has been proposed, and the International Optical Disk Standardization Plenary Conference (ISO
) has been studied.

However, as the disk is used repeatedly, the magnetic material attached to the hub has a significantly different coefficient of thermal expansion than normal hub materials, so if the disk is used for a long period of time, it may peel off from the hub due to changes in environmental temperature. .

[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.

[Summary of the Invention] The present invention has a spindle insertion hole in the center of an information recording disk that has a through hole in the center and can write and/or read information using a laser, and a magnetically sensitive material. An information recording medium in which a hub made of thermoplastic resin is attached to which the magnetic material is attached, and the magnetically sensitive material is separated from the hub by a protrusion having a bulge at the end provided on the surface of the hub. This information recording medium is characterized in that a magnetically sensitive material is attached to the surface of a hub in a state where the magnetism is prevented.

[Detailed Description of System 11] The present invention will be described in detail with reference to the accompanying drawings.

A typical aspect of the information recording medium of the present invention is, for example, the first
It has a configuration as shown in the figure, and FIG. 2 shows a bottom view of the magnetically sensitive hub 20 shown in FIG. 1.

That is, the information recording medium of the present invention basically consists of an information recording disk 10 and a magnetically sensitive hub 2o, and has a configuration in which the magnetically sensitive hub 20 is attached to a central through hole of the information recording disk 10. be.

The information recording disc IO has a recording layer 12 provided on a substrate 11, and a protective layer [3] further provided thereon. A thermoplastic resin hub 2° having a spindle insertion hole 21 and equipped with a magnetically sensitive member 14 is bonded to the through hole of the information recording disk 1o.

The magnetically sensitive body 22 has a ring-like shape with a through hole in the center for passing a spindle through, and a through hole for engagement with a protrusion is formed on its surface in point symmetry with the through hole.

The magnetically sensitive body 22 is attached to the surface of the hub 20 in a state where it is prevented from detaching from the hub 20 by a bulge 24 at the end of the protrusion provided on the surface of the hub 20. In the information recording medium of the invention, the magnetically sensitive body is attached to the surface of the hub by mechanical engagement of the magnetically sensitive body and the bulge provided at the end of the protrusion, but at the same time, the magnetically sensitive body is attached to the surface of the hub. It may also be adhered to the surface of the hub with an adhesive or the like.

3(a) to 3(b) are diagrams showing the manufacturing process of the hub 20 of the information recording medium shown in FIG. 2.

First, in a first step (a), a hub made of thermoplastic resin is prepared, in which a protrusion 23 without a bulge is formed on the surface of the hub 20, and in a second step (b), a hub made of thermoplastic resin is prepared. A magnetically sensitive body 22 having a through hole is fitted therein.

Then, in a third step (C), the ends of the protrusions 23 are thermally melted and then solidified to form the bulges 24. The magnetically sensitive body 22 is prevented from detaching from the hub 20 by the bulge 24 formed in this way, and is attached to the surface of the hub 20.

The hub 20 can be manufactured as follows.

4 and 5 show another embodiment of the information recording medium of the present invention. In FIG. 4, the magnetically sensitive hub 50 is attached to the information recording disk 4.
It is configured to be installed in the central through hole of 0. Fifth
The figure shows a bottom view of the magnetically sensitive hub 50 shown in FIG.

The information recording disk 40 has a recording layer 42 provided on a substrate 41, and a protective layer 43 further provided thereon. A hub 50 made of thermoplastic resin, which has a spindle insertion hole 51 and is equipped with a magnetically sensitive material 52, is bonded to the through hole of the information recording disk 40.

The magnetically sensitive body 52 is prevented from detaching from the hub 50 by the bulges 54 and 56 provided at the respective ends of the inner protrusion 53 and the outer protrusion 55 provided on the surface of the hub 50. It is attached to the surface of the hub 50 in a state where it is attached.

Note that the information recording medium shown in FIGS. 1.2.4 and 5 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.

Further, the information recording medium of the present invention may be of a bonded type or an air sandwich type.

The information recording medium of the present invention can be manufactured, for example, as follows.

First, the magnetically sensitive hub that is bonded to the information recording disk will be explained.

The material for the magnetically sensitive hub body is not particularly limited as long as it is a thermoplastic resin that can be easily handled during molding, and examples include synthetic resins such as polyolefin, vinyl chloride resin, polycarbonate resin, polyacrylic resin, and acetal resin. Can be done. In order to match the thermal expansion coefficient and hygroscopic expansion coefficient of the substrate and the hub, it is preferable that the substrate and the hub be made of the same material, and examples of materials that can be used for both include polycarbonate resin and polyacrylic resin.

The hub can be manufactured by injection molding, and in order to achieve good bonding to the information recording disk, the top of the hub has a spindle insertion hole in the center, and is a cylindrical cylinder that is inserted into the through hole of the information recording disk. A section may be provided.

The hub may be provided with a recording section containing optically readable information, or the surface of the hub on the side to be joined to the disk so that adhesive or the like does not leak into the recording section of the information recording disk. A groove may be provided for accommodating adhesive.

A magnetically sensitive material is attached to the hub, and the magnetically sensitive material is made of a magnetically sensitive material such as iron or an alloy containing iron, and is preferably made of a material that is resistant to rust. Although there is no particular limitation on the shape, typical shapes include a plate shape, a rod shape, a ring shape, and the like. The magnetically sensitive body attached to the hub may be coated with resin, and the hub to which the magnetically sensitive body is attached is bonded to the information recording disk.

Next, the information recording disc will be explained.

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;
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, polycarbonate, etc., and polymeric substances such as nitrogen coupling agents. Organic substances: and inorganic oxides (
Examples include inorganic substances such as Si02, Al2O, etc.) and inorganic fluorides (MgF2).

Examples of materials used for the recording layer include Te, Zn, I
n, Sn, Zr, An, Ti, Cu, Ge, Au, P
Examples include metals such as T; 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, 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 is formed by vapor depositing and sputtering the above materials.

It can be formed directly on the substrate or via an undercoat layer by a method such as 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 densities, preferably in the range of tso to 1,000 densities, in view of the optical density required for optical information recording.

A protective layer may be provided on the recording layer for the purpose of improving mechanical strength or the like.

Examples of materials used to form the four layers include S 1
Examples include inorganic substances such as O1Si02 and MgF2.5n02, and organic substances such as thermoplastic resins, thermosetting resins, and UV curable resins.

The protective layer is formed by laminating, for example, a film obtained by extrusion of plastic onto the recording layer (or laser light sensitizer layer or laser light reflecting layer) and/or onto the substrate via an adhesive layer. be able to. Alternatively, it may be applied by methods such as vacuum evaporation, sputtering, and coating. In the case of thermoplastic resins and thermosetting resins, the coating solution is prepared by dissolving these in an appropriate solvent, and then the coating is applied. It can also be formed by applying a liquid and drying it. In the case of a UV curable resin, it can also be formed by preparing a coating liquid as it is or by dissolving it in an appropriate solvent, applying this coating liquid, and curing it by irradiating it with UV light. These coating solutions further contain antistatic agents, antioxidants, and U.
Various additives such as V absorbers may be added depending on the purpose.

The thickness of the protective layer is generally in the range 0.1-100 lumen.

The surface of the substrate opposite to the side on which the recording layer is provided is coated with organic substances such as silicon dioxide, tin oxide, and magnesium fluoride in order 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.

Finally, the joining of the magnetically sensitive hub and the information recording disk will be explained.

Various known adhesives can be used to bond the magnetically sensitive hub to the information recording disk, such as ultraviolet curing acrylic adhesive, ultraviolet curing epoxy adhesive,
Examples include ultraviolet curable ene-thiol adhesives, thermosetting epoxy adhesives, thermosetting urethane adhesives, silicone adhesives, and hot melt adhesives.

The magnetically sensitive hub can be joined to the information recording disk by melting and adhering the substrate or part of the hub using ultrasonic waves, or it is also possible to join by mechanical engagement. .

As described above, the information recording medium of the present invention can be manufactured.

[Effects of the Invention] In the information recording medium of the present invention, the magnetically sensitive body is mechanically engaged with the bulge provided at the end of the protrusion on the hub surface, and the magnetically sensitive body is attached to the surface of the hub. Because the hub is attached to the hub, the magnetically sensitive material will not peel off from the hub due to long-term use or changes in environmental temperature, allowing good rotational drive to be maintained.

[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 bottom view of the magnetically sensitive hub of FIG. 1; FIG. FIG. 3 is a sectional view showing the manufacturing process of the magnetically sensitive hub of FIG. 1. FIG. 4 is a sectional view of the central portion showing the configuration of another embodiment of the information recording medium of the present invention. 5 is a bottom view of the magnetically sensitive hub of FIG. 4; FIG. 10.40: Information recording disk 11.41: Substrate 12.42: Recording layer 13.43: Protective layer 20.50: Hub (magnetic hub) 21.51 Spindle insertion hole 22/52: Magnetically sensitive material 23 : Protrusion 53: Inner circumference side protrusion 55: Outer circumference side protrusion 24, 54, 56: Swelling part Patent applicant: Fuji Photo Film Co., Ltd. Agent: Patent attorney: Yasushi Yanagawa (Figure 1, M3, Figure 4, Figure 5)

Claims (1)

[Claims] 1. An information recording disk having a through hole in the center and on which information can be written and/or read by a laser has a hole for inserting a spindle in the center, and a magnetically sensitive material is inserted into the through hole. An information recording medium in which an attached thermoplastic resin hub is bonded, and the magnetically sensitive material is prevented from detaching from the hub by a projection having a bulge at the end provided on the surface of the hub. An information recording medium characterized in that a magnetically sensitive material is attached to the surface of a hub in a state where the magnetic material is 2. After attaching a magnetically sensitive material to the area where the bulge of the protrusion provided on the hub is formed by the base of the protrusion that does not have a bulge at the end provided on the hub and the surface of the hub. 2. The information recording medium according to claim 1, wherein the bulge is formed by heating, melting, and solidifying the end of the protrusion. 3. The magnetically sensitive body has a through hole, and the magnetically sensitive body is attached to the hub by engagement of the through hole with a protrusion of the hub. Information recording medium. 4. Claim 1, characterized in that the bulging portion of the protrusion provided on at least one of the inner and outer surfaces of the hub prevents the magnetically sensitive body from detaching.
Information recording medium described in section.