JPH063674B2 - Information disc - Google Patents

Description

The present invention relates to a magnetic disk, such as an optical disk or a magneto-optical disk, on which information signals are recorded.

[Summary of the Invention] According to the present invention, a hub is fixed by ultrasonic fusion so that a ring-shaped magnetic body is sandwiched between the central portion of a central hole of an information disc body on which an information signal is recorded and the information disc body. By doing so, it is possible to use only the magnet provided in the above-described example of the disk rotation drive device without providing a disk presser or the like to be sandwiched in the disk rotation drive device provided with the disk centering member such as the centering member provided on the rotation drive device side. This is an information disc that is clamped and can rotate integrally with the above-mentioned rotation drive device.

[Conventional technology]

Conventionally, information discs such as optical discs and magneto-optical discs have an information signal recording layer provided on one main surface of a hard substrate obtained by molding a synthetic resin such as a polycarbonate resin, and the synthetic resin is protected on the recording layer. It is configured by laminating films.

Further, in order to perform accurate recording and reproduction of information signals, this type of information disc needs to be accurately rotationally driven with a constant rotation speed during recording and reproduction.

Therefore, in a recording / reproducing apparatus such as a disc player using the above-mentioned information disc as a recording medium, the disc is rotated integrally with a disc table of a disc rotation driving device which is rotationally controlled and controlled to have a constant rotation speed. So that the information disc is clamped to the disc table. It is known to use a magnet as a means for clamping this information disc on a disc table.

As a conventionally used disk clamping device using the above-mentioned magnet, one shown in FIG. 4 is known. This clamp device includes a yoke 4 integrally attached to a tip end of a spindle 3 of a disc rotation drive device integrally attached with a disc table 2 on which an information disc 1 is mounted, a support arm or a rotatable opening / closing. Lid 5
And a magnet 7 attracted to the yoke 4 attached via a disc retainer 6 which is attached to the back side of the disc and is capable of coming in and out of contact with the disc table 2. Then, the information disc 1 has a center hole 1a engaged with a centering member 9 which is biased upward by a spring 8 which is supported between a disc table 2 and a yoke 4 via a spindle 3 so as to be vertically movable. The spindle 3 is centered and placed on the disk table 2, and the yoke 7 is made to attract the magnet 7 to be sandwiched by the disk retainer 6 and the disk table 2 which are brought close to the disk table 2. It is attached and integrated with the disc table 2, and can rotate in synchronization with the disc table 2.

[Problems to be Solved by the Invention]

By the way, the above-mentioned conventionally used information disc 1
Is mainly made of a synthetic resin disk substrate and is not provided with any magnetic member for magnetic attraction. Therefore, in order to clamp the information disk 1 by magnetic attraction as in the above-described clamping device, the yoke 4 is used. A disc holder 6 having a magnet 7 is required together with the disc table 2 provided with. The disc holder 6 that presses and supports the information disc 1 from above the disc table 2 needs to be attachable to and detachable from the disc table 2 so that the information disc 1 can be attached and detached. Therefore, in order to clamp the above-mentioned conventional information disc 1 by magnetic attraction, a clamping device having a disc retainer 6 is required. In a recording and / or reproducing apparatus in which the information disc 1 is clamped and rotationally driven by using the clamp device having the disc retainer 6 as described above, it is necessary to provide a moving space for the disc retainer 6 in the device. Therefore, it is extremely difficult to reduce the thickness and size of the device itself.

Therefore, the present invention has been proposed for the purpose of providing an information disc that can be clamped by magnet attraction without using the disc retainer as described above.

By enabling the disc table to be clamped without providing a disc retainer, it is possible to achieve a thin and compact recording / reproducing apparatus such as a disc player using the information disc according to the present invention as a recording medium. To aim.

[Means for Solving the Problems]

In order to achieve the above-mentioned object, the present invention has an information disc main body in which a center hole in which a disc centering member such as a centering member provided on the rotary drive side is engaged, and an information signal is recorded. A ring-shaped magnetic body and a hub for sandwiching the ring-shaped magnetic body together with the information disc body, and the hub is fixed to the central hole peripheral portion of the information disc body by ultrasonic fusion to form the ring. The magnetic material is sandwiched between them.

[Work]

In the information disc according to the present invention, the ring-shaped magnetic body attached to the information disc body is attracted to the magnet provided on the disc table of the disc rotation drive device, and is clamped on the disc table and integrated with the disc table. Driven to rotate.

〔Example〕

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

As shown in FIGS. 1 and 2, the information disk 11 according to the present invention is an optical system using a laser beam on one main surface of a hard substrate obtained by forming a synthetic resin such as a polycarbonate resin, or An information disk main body 12 having an information signal recording layer for recording an information signal by a magneto-optical system and a synthetic resin protective film laminated on the recording layer, and a ring shape made of a magnetic metal such as iron. It is composed of a magnetic body 13 and a hub 14 which holds the ring-shaped magnetic body 13 together with the information disk body 12.

The information disc main body 12 is provided with a central hole 15 in the center thereof, into which a centering member as a rotation driving member which is vertically movable is provided at the upper end side of the spindle of the disc rotation driving device. This central hole 15
Tapered surfaces 15a and 15b, which serve as guide surfaces during insertion and engagement with the centering portion, are formed at both upper and lower ends of the. In addition, a non-signal recording area where an information signal recording layer is not formed is formed on the outer peripheral portion of the center hole 15.

The ring-shaped magnetic body 13 is formed by punching a thin iron plate, which is a magnetic metal, in a ring shape, and has a size such that it can be mounted at least in the non-signal recording area when mounted on the information disk body 12. Has been formed.

Further, the hub 14 is formed of a synthetic resin such as a polycarbonate resin which is the same material as the substrate which is the main constituent member of the information disc body 12. This hub 14
The insertion hole 16 formed in the center of the ring-shaped magnetic body 13 has a diameter d ₂ smaller than the diameter d ₁ of the insertion hole 16 on the tip end side of the ring-shaped magnetic body 13 and can be fitted with a slight gap. A fitting portion 17 is formed which is approximately the same as or slightly higher than the thickness of the magnetic body 13 and has a flange on the base end side, the diameter being larger than the diameter d _{1 of the} insertion hole 16 and supporting the peripheral edge of the insertion hole 16. The part 18 is formed. Further, an ultrasonic fusion-bonding portion 19 serving as a fixing portion to the information disk body 12 is formed as a ring-shaped protrusion on the tip end surface of the fitting portion 17. Further, in the center of the hub 14, the through hole 2 is tapered toward the tip of the fitting portion 17.
0 is provided. The through hole 20 is formed so that the minimum diameter d ₃ on the tip end side which is tapered is larger than the maximum diameter d ₄ of the tapered surfaces 15a and 15b of the central hole 15 of the information disk body 12. Then, when the hub 14 is fixed to the information disk body 12 and placed on the disk table of the rotation drive device, the centering member serves as the through hole 20.
It is designed so that it is not locked to the peripheral surface.

The ring-shaped magnetic body 13 is fitted into the fitting portion 17 of the hub 14 thus formed. This ring-shaped magnetic body 13
The center of the through hole 20 is aligned with the center of the center hole 15 of the information disk body 12 in the hub 14 into which the fitting portion 1 is fitted.
The ultrasonic welding portion 19 at the tip of the 7 is disposed in contact with the peripheral portion of the center hole 15. Here, ultrasonic waves are applied to the ultrasonic fusion portion 19 to melt it and fuse it to the information disk body 12 to fix the hub 14. When the hub 14 is fixed in this manner, the ring-shaped magnetic body 13 fitted in the fitting portion 17 is attached.
Is fixed to the information disk body 12 without being fixed to the information disk body 12, and the information disk 11 shown in FIG. 1 is mounted so as to be sandwiched between the flange portion 18 of the hub 14 and the information disk body 12. The ring-shaped magnetic body 13 has a larger diameter insertion hole 1 depending on the diameter d ₂ of the fitting portion 17.
6 and is formed to be the same as or thinner than the height of the fitting portion 17, the information disk body 12 is supported so as to be slightly movable in the horizontal direction.

As shown in FIG. 3, the information disk 11 is mounted on the disk table 22 of the disk rotation drive device in which the magnet 23 is arranged on the disk mounting surface side of the disk table 22 integrally attached to the spindle 21. It is clamped so as to be integrated with the disc table 22 simply by placing it. That is, the information disc 11 has the center hole 1 in the centering member 25 which is attached to the upper end side of the spindle 21 by the spring 24 so as to be vertically movable.
When 5 is inserted and placed on the disk table 22, the ring-shaped magnetic body 13 is attracted to the magnet 23 and clamped on the disk table 22. Then, the information disc 11 has the centering member 2 in the process of inserting the center hole 15 into the centering member 25.
5 by the vertical movement of 5 and the guide by the inclined guide surface 26 formed on the outer peripheral surface of the centering member 25.
1 is centered and clamped on the disc table 22. Further, when the information disk 11 is placed on the disk table 22, the through hole 20 of the hub 14 is formed in a taper shape and the peripheral surface is an inclined surface, so that the centering member 25 serves as a guide when inserting. The centering member 25 can be smoothly inserted.
Further, since the minimum diameter d ₃ on the tip end side of the through hole 20 is larger than the maximum diameter d ₄ of the tapered surfaces 15a and 15b of the central hole 15, the centering member when the information disk 11 is clamped. 25 is a tapered surface of the center hole 15 without being locked in the through hole 20 of the hub 20.
5b is contacted and locked. Further, the centering of the information disk body 12 with respect to the spindle 21 can be achieved without being influenced by the mounting accuracy of the hub 20. That is, centering is achieved while maintaining the accuracy of the central hole 15 provided in the information disc body 12.

〔The invention's effect〕

As described above, according to the present invention, since the ring-shaped magnetic body is attached to the information disc body, the yoke which is opposed to the magnet forming the magnetic field of the magnet as a closed magnetic path is not required. Since the disc can be clamped on the disc table of the disc rotation drive device provided with a magnet without using the disc retainer required in the drive device, the above device can be made thin, and the recording / reproducing device such as a disc player can be made thin. The miniaturization and size reduction are achieved, the number of parts for clamping the disc is reduced, and the configuration is simplified.

Further, since the information disc according to the present invention is mounted in a free state with a gap to the hub without fixing the ring-shaped magnetic body, the difference in thermal expansion between the information disc body and the ring-shaped magnetic body is absorbed. be able to. That is, even when the information disk is thermally expanded in an atmosphere at a high temperature, deformation caused by a difference in coefficient of thermal expansion between the information disk body mainly made of synthetic resin and the ring magnetic body made of iron or the like is prevented. can do.

Further, since the hub is ultrasonically fused near the innermost periphery of the non-signal recording area of the information disc body, the signal recording layer is not affected by the heat generated at the time of this fusion.

[Brief description of drawings]

1 is a sectional view showing an information disk according to the present invention, FIG. 2 is an assembled sectional view thereof, and FIG. 3 is a sectional view showing a state of being clamped to a disk rotation drive device. FIG. 4 is a sectional view showing a state in which a conventional information disc is clamped to a disc rotation drive device. 11 ... Information disc 12 ... Information disc main body 13 ... Ring-shaped magnetic body 14 ... Hub 19 ... Ultrasonic welding portion

Claims (1)

[Claims] 1. An information disc main body having a central hole into which a disc centering member on the side of a rotation drive device engages, and an information signal is recorded, a ring-shaped magnetic body, and the ring-shaped magnetic body. A hub for sandwiching the ring-shaped magnetic body with the information disc body, the hub being secured to the peripheral portion of the center hole of the information disc body by ultrasonic fusion. Information disc.