JP2593482B2 - optical disk - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk with a hub, and more particularly to optimization of a hub configuration in a single disk, improvement in reliability when clamping the optical disk, and downsizing of the device. And an optical disk with a hub that achieves the above.

[Conventional technology]

Conventionally, an optical disk clamping method has been performed by engaging a turntable for holding the optical disk and a clamper for pressing the optical disk from above, but requires a smaller optical disk device (especially a reduction in height). Therefore, as described in the article of Nikkei Electronics on November 17 and December 29, 1986, in a data optical disk, a hub provided with a magnetic material was provided on an optical disk, and a magnet provided in a turntable was provided. It has been considered that the optical disk is clamped by a magnetic coupling force with the optical disk, thereby removing a clamper and the like provided at the upper part in the related art, thereby achieving downsizing.

[Problems to be solved by the invention]

Since the above-mentioned prior art has an optical disk configuration in which two single-plate disk-shaped information media are bonded together, the hub configuration has a surface for irradiating the light spot of each single-plate disk (second aspect of the present invention).
Surface), a hub having a magnetic material is fixed to the optical disk, so that the hub protrudes from the lower surface of the optical disk. At present, studies are being made on magneto-optical disks and the like. However, since the studies on optical disks here are limited to single-plate disc-shaped information media, the hub structure of conventional bonded optical disks is However, no consideration has been given to a single disk, and there is a problem that further miniaturization of the single disk cannot be achieved. Further, in the conventional hub configuration, when the fixed portion between the hub and the optical disk is disengaged, the optical disk becomes free, and there is a problem that the optical disk may be damaged or the device may be damaged. There is a need.

SUMMARY OF THE INVENTION It is an object of the present invention to construct a hub configuration that is optimal for a single-disc disk-shaped information medium, to reduce the size of the device, and to improve the reliability of the fixed system.

[Means for solving the problem]

In order to achieve the above object, according to the present invention, a hub member made of a synthetic resin material has a fixed portion fixed to a first surface provided with an information recording portion of a single-plate single plate disk. By this, a convex portion attached to the single-plate disk and projecting in the axial direction from a fixing portion of the hub member is inserted into the disk center hole, and the convex portion has a smaller diameter than the disk center hole, A magnetic member having a diameter smaller than the center hole of the disk is provided at the tip of the convex portion, and the magnetic member protrudes on the second surface side of the single-plate disk opposite to the first surface, Further, a gap is provided between the protruding portion and the disk center hole at a predetermined interval in the radial direction, and furthermore, a clamp area to be clamped by the rotation drive unit of the optical disk device is provided for the single disk. On the second surface, in the radial direction Outside diameter side than the disk center hole, and to be positioned within the outer diameter of the fixed portion of the hub member.

[Action]

The synthetic resin material constituting the single-plate disk or the convex portion and the magnetic member have different coefficients of thermal expansion, and the amounts of thermal expansion due to temperature changes are different. However, in the present invention, the magnetic member is projected from the disk center hole of the single-plate disk to the second surface side of the single-plate disk, and a gap is provided at a predetermined interval between the convex portion and the disk center hole. Therefore, even if the amount of thermal expansion at the distal end where the convex magnetic member is provided may be restricted by the amount of thermal expansion of the magnetic member due to a temperature change, the single-plate disk is affected by this. And no undesired deformation occurs. Moreover, as described above, by providing a gap at a predetermined interval between the convex portion and the disk center hole, even if the magnetic member is set at a position substantially the same as the second surface of the single-plate disk, Since the influence of the difference in the coefficient of thermal expansion between the synthetic resin material and the magnetic member can be prevented, the thickness of the optical disk is not increased.

Further, the clamp area set on the second surface of the single-disc disk is substantially in front of the fixed portion of the hub member fixed on the first surface, and the present invention is mounted on the rotation drive unit of the optical disk device. In this case, the magnetic member provided on the convex portion is attracted by magnetic attraction means provided on the rotary drive unit, and the clamp area is fixed so as to abut the turntable of the rotary drive unit. In this state, the fixed portion and the turntable are opposed to each other in front of each other to clamp the single-disc disk, so that the turntable is stable. Even if the single disk is disengaged from the how member by clamping, the single disk does not become free.

〔Example〕

 Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of a configuration of an optical disk with a hub showing one embodiment of the present invention, FIG. 2 is a configuration diagram showing a clamped state of the optical disk with a hub in an optical disk device, and FIG. FIG. 4 is an explanatory diagram of the system, and shows another embodiment of the optical disk with a hub.

In the figure, reference numeral 1 denotes a single-disc disk including a first surface 1a having an information recording unit 2, a second surface 1b on which a light spot 5 is irradiated, a center hole 3, and the like, and 10 denotes a first surface of the single-disc disk 1.
Reference numeral 1 denotes a hub holder having a fixed portion 11a and a hub provided with a magnetic body 12 on the second surface 1b side of the single-plate disk 1, 20 a disk motor, 21 a spindle, and 22 a turntable provided with a magnet 23.

 Next, the operation will be described.

The configuration of the optical disk with a hub according to the present invention will be described with reference to FIG.

A single disk 1 (for example, a CD: the same as a compact disk) has a first surface 1a having an information recording unit 2, a second surface 1b for irradiating the information recording unit 2 with a light spot 5, a center hole 3, and the like. It is a configured disc-shaped information medium. A hub 10 is provided by utilizing the center hole 3 of the single-plate disc 1 to constitute an optical disc with a hub. That is, a hub holder 11 having a fixed portion 11a fixed to the first surface 1a having the information recording portion 2 of the single-plate disc 1 and a convex portion 11b protruding in the axial direction from the fixed portion 11a is provided. Convex part 1
1b is inserted into the center hole 3 of the single-disc disk 1, and the magnetic body 12 is fixed to the front end surface of the single-disc disk 1 on the third surface 1b side, thereby forming an optical disk with a hub. In addition, a hub holder engaged with the center hole 3 of the single-plate disc 1
The dimension of 11 is slightly smaller than the dimension of the center hole 3 (about 14.5 mm to 14.7 mm for a center hole diameter of 15 mm). As is clear from FIG.
A gap is provided between the center hole 11b and the center hole 3 at a predetermined interval in the radial direction. Further, as is clear from FIG. 1, the magnetic body 12 provided on the tip end surface of the convex portion 11b is
Although it protrudes from the center hole 3, the second
It is located at substantially the same position as the plane including the surface 1b. In addition, in the optical disk with a hub of the present invention, even if the single disk 1 is provided with the hub 10, the thickness can be made substantially the same as the thickness of the single disk 1, and the apparatus can be downsized (thickness Reduction)
Can be achieved.

Next, with reference to FIG. 2, the clamping method of the optical disk with a hub of the present invention in the optical disk device will be described.

In the clamping method of the optical disk with a hub, a clamp area of the second surface 1b of the single disk 1 is held on a turntable 22 fixed to a spindle 21 of a disk motor 20, and a center hole 12a of a magnetic body 12 of the hub 10 is provided. And spindle 21
The center position of the optical disk with a hub is determined by the engagement of. The clamping force of the optical disk with a hub is reliably clamped by the magnetic attraction between the magnetic body 12 of the hub 10 and the magnet 23 fixed in the tongue table 22.

Therefore, in the conventional optical disk with a hub shown in FIG. 5, the hub 10 of the optical disk 7 is connected to the second surface 7b of the optical disk 7.
When the turntable 22 that holds the optical disk 7 is positioned at the same position, the hub 10 is inserted into the turntable 22, so that the position of the magnet 23 that generates the clamping force is below. Will be prepared for
The thickness of the turntable 22 is increased.
Further, by fixing the hub 10 to FIG. 7B, the diameter of the turntable 22 must be larger than the outer diameter of the hub holder 11. The optical head 30 is compared with the optical disk 7
It is also conceivable that the recording capacity cannot be moved to the inner periphery of the recording medium and the recording capacity is reduced. Further, since the conventional hub 10 is fixed on the second surface 7b side of the optical disk 7 held on the turntable 22, if the optical disk 7 and the hub 10 are unlocked, the optical disk 7 becomes free. It is conceivable that the optical disk, the optical head, the mechanical system, and the like may be damaged in the optical disk device. However, in the optical disk with a hub of the present invention, as described above, the fixing portion 11a of the hub holder 11 of the hub 10 is the first surface 1a of the single disk 1.
In addition, as is clear from FIG. 2, the area where the turntable 22 contacts the second surface 1b of the single disk 1, that is, the clamp area is located outside the center hole 3 of the single disk 1. A region on the radial side and within the outer diameter of the fixed portion 11a, which is substantially opposed to the fixed portion 11a in front of the fixed portion 11a. However, since the turntable 22 and the veneer disk 1 which face each other are sandwiched, the veneer disk 1 does not become free and there is no problem such as breakage.

Next, referring to FIG. 3, the hub holder 11 of the hub 10 and the magnetic body 12
Will be described.

FIGS. 3 (a) and 3 (b) show the hub holder 11 and the magnetic body 12 integrally molded and fixed.

That is, FIG. 3 (a) shows that several places of the magnetic
When the hub holder 11 is formed, the magnetic body 12 is also integrally formed (by an outsert method or an insert method) so as to form the recess 12b.
The resin of the hub holder 11 is caused to flow through the hole 12c and fixed.

Further, FIG. 3 (b) shows that the magnetic body 12 is cut and raised in several places, and the magnetic body 12 is integrally formed when the hub holder 11 is formed. The hub holder 11 is fixed by pouring the resin therein.

FIG. 3 (c) shows a magnetic body 12 fixed to a hub holder 11 by screws 13. Note that the screw mounting portion 12 of the magnetic body 12 is
e has a concave configuration. In the fixing method using the screw 13, the outer diameter of the magnetic body 12 can be made larger than the diameter of the center hole 3 of the single disk 1 as shown in the figure, and the magnetic coupling force can be increased. It is.

Although not shown in the figure, the hub holder
There is no problem even if the magnetic material 12 is adhered to 11. The single disk 1 and the fixing portion 11a of the hub holder 11 are fixed by a bonding method, a welding method using ultrasonic waves, or the like. The hub holder 11 is made of a material having the same performance (coefficient of thermal expansion, specific gravity, etc.) as the single disk 1 due to the improvement of the characteristics of the single disk 1.

The single disk 1 is also made of a synthetic resin material such as a CD, for example. However, the synthetic resin material of the single disk 1 and the hub holder 11 and the magnetic material have a coefficient of thermal expansion. In contrast, the synthetic resin material has a larger coefficient of thermal expansion. Therefore, when there is a change in temperature, the synthetic resin material has a larger thermal deformation amount. For example, when the temperature is lowered and the thermal shrinkage occurs, the synthetic resin material has a larger thermal shrinkage amount. However, since the magnetic body 12 is provided at the tip of the convex portion 11b of the hub holder 11, the amount of heat shrinkage is smaller than other portions of the synthetic resin material. As shown in FIG. 1, if there is no gap between the protruding portion 11b and the center hole 3 of the single-plate disc 1, as shown in FIG. May affect the single-disc disk 1 and cause undesired deformation. In particular, the second
The clamp area of the surface 1b on the side of the center hole 3 is easily affected by this. However, in this embodiment, the magnetic material 12
Is protruded from the center hole 3 of the single-disc disk 1, and a gap of a predetermined size is provided between the convex portion 11b and the center hole 3 of the single-disc disk as described above. Can be eliminated.

FIG. 4 shows another embodiment of the optical disk with a hub according to the present invention. Particularly, the configuration of the hub 10 is different.

That is, in the present embodiment, the shape of the magnetic body 12 is such that the fixing portion 12 with the hub holder 11 is provided on the first surface 1a side of the single-plate disc 1.
f, and a magnetic coupling side 12g is provided on the second surface 1b side of the single disk 1 via the center hole 3 of the single disk 1.

That is, the magnetic member 12 is configured such that the diaphragm portion has a diameter slightly smaller than the diameter of the center hole 3 of the single-plate disc 1. The height of the drawn portion is about the thickness of the single-plate disc 1 (about 1.2 mm), and there is no problem during molding.

That is, in this configuration, since the fixing portion 12e of the magnetic body 12 with the hub holder 11 is provided on the first surface 1a side of the single-plate disc 1, the fixing portion 12e of the hub holder 11 with the magnetic body 12 is disengaged. However, the single disk 1 does not become free, and the reliability in the clamped state can be further improved.

〔The invention's effect〕

As described above, according to the present invention, the clamp area to be clamped to the turntable of the rotation drive unit of the optical disk device is located on the outer diameter side of the disk center hole on the second surface of the single-plate disk, and Since it is the area within the outer diameter of the fixed part of the main body, when it is mounted on such a rotary drive, the fixed part and the turntable, which face each other in front, will clamp the single disk, and a stable clamping state will be achieved. As a result, even if the veneer disk comes off the hub member, the veneer disk does not become free.

Further, according to the present invention, the convex portion of the hub member inserted into the disk center hole of the single-plate disk has an outer diameter smaller than that of the disk center hole, and has a predetermined distance from the disk center hole. Since a magnetic member provided at the tip of the convex portion and having a smaller diameter than the disk center hole protrudes from the disk center hole to the second surface side of the single disk, There is a difference in the coefficient of thermal expansion between the magnetic resin and the synthetic resin material that forms the veneer disk or the convex portion, and even if there is a difference in the amount of thermal expansion due to a temperature change between them, the veneer is affected by this. There is no unwanted deformation of the disk. Moreover, even if the magnetic member is projected from the center hole of the disk toward the second surface of the single-plate disk, a gap is provided at a predetermined distance from the center hole of the disk. Thus, it is possible to prevent the above-mentioned influence due to the difference in the thermal expansion coefficient.

Further, according to the present invention, the magnetic member has a smaller diameter than the disk center hole of the single-plate disk, and the clamp region of the single-plate disk is on the outer diameter side of the disk center hole. The arrangement area of the members is not divided and overlapped in the radial direction of the single-plate disk, and therefore, the optical disk can be made thinner.

Further, according to the present invention, since the hub member is not clamped in the clamp area on the second surface of the single-plate disk and does not serve as a clamp surface, even if there is a shape error of the hub member or a mounting error to the single-plate disk, this will not occur. Does not affect clamping.

Further, according to the present invention, when the magnetic member is clamped to the turntable, the magnetic member comes close to the magnetic attraction means of the rotation drive unit of the disk device, thereby increasing the magnetic attraction force. The magnetic member is
Since it is close to the magnetic attraction means and distant from the first surface on which the information recording portion of the single-plate disk is provided, magnetic leakage to the first surface is reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a configuration of an optical disk with a hub showing one embodiment of the present invention, FIG. 2 is a configuration diagram of a clamp of an optical disk with a hub in an optical disk device, and FIG. FIG. 4 is a sectional view showing the structure of another embodiment of the optical disk with a hub, and FIG. 5 is a diagram showing the structure of a clamp for a conventional optical disk with a hub. DESCRIPTION OF SYMBOLS 1 ... Single disk, 2 ... Information recording part, 3 ... Center hole, 10 ... Hub, 11 ... Hub holder, 12 ... Magnetic body, 20 ... Disk motor, 21 ... Spindle, 22 ... Turntable, 23 ... magnet.

Claims (1)

(57) [Claims] An information recording section is provided on a first surface side of a single-plate-shaped single-disc disk at a center portion thereof, and the information recording section is provided on the opposite side of the first surface from the first surface. Second
In an optical disc irradiated with light from the surface side, the single-plate disc has a disc center hole in the center thereof, the hub member is a hub body member made of a synthetic resin material,
The hub body member is provided integrally with the hub body member and has a magnetic member having a smaller diameter than the disc center hole. The hub body member has a fixed portion having a predetermined width in the radial direction, The magnetic member is provided at the tip end side, and the outer diameter is smaller than the diameter of the disc center hole by a predetermined dimension. The hub member is configured such that the convex portion is inserted into the disc center hole from the first surface side, and is attached to the first surface of the single-plate disc by the fixing portion. The convex portion is fitted with a predetermined interval in the radial direction between the disc and the center hole of the disc, and the magnetic member is formed to protrude toward the second surface. The clamp area to be clamped by the drive unit is Optical disc, characterized in that a second side of the plate disk, comprising the outside diameter side from the disk center hole in the radial direction, and is disposed within the outer diameter of the fixing portion of the hub body member.