JPH09223376A - optical disk - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To prevent a center hub from falling out of a center hole of a disc. An optical disc (1) has a center hub (4) attached to a center hole (3) of an optical disc substrate (2), and by using the center hub (4), it is chucked to a magneto-optical disc recording / reproducing apparatus having a hub chucking mechanism. It is designed to rotate. Center hub 4 above
Is a bottomed cylindrical shape made of a magnetic material, has a spindle bearing hole 14 in the center of the bottom plate 13, and is inserted into the center hole 3 of the optical disc substrate 2 through the center hole insertion portion 11
And is formed integrally with one end of the center hole insertion part 11 and is superposed on the surface of the optical disc substrate 2 when the center hole insertion part 11 is inserted into the center hole 3. It is provided with a flange-shaped annular portion 12. The center hub 4 has the center hole insertion portion 11
The optical disk substrate clamping means 5 is provided so as to protrude toward the outer peripheral surface side and clamp the peripheral edge of the center hole 3 of the optical disk substrate 2 with the annular portion 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a read-only optical disc such as a compact disc (CD) or a CD-ROM which is widely used as a recording medium for music, and more particularly,
The present invention can be applied to a recording / reproducing device for a magneto-optical disk that can also record.

[0002]

2. Description of the Related Art Technologies for transmission, recording, terminals, and the like that integrally handle various types of information such as images, sounds, and data, that is, so-called multimedia have been actively developed. For example, in addition to information that can be conventionally processed such as numerical values, characters, and graphics in a terminal computer, time-series data such as audio and video are associated with each other and handled in synchronization, which is also one form of this multimedia. This technology aims to provide personal computers with a sense of realism and ease of use that exceeds that of books and televisions by adding audio and video to the terminal computer, and is expected to be applied to education, information retrieval, games, etc. I have.

As described above, in order for a computer to handle media data such as video and audio, a large-capacity recording medium for supplying or storing such media data is indispensable. Optical discs are regarded as promising to meet such demands, and computers already equipped with recording / reproducing systems for CD / ROM and magneto-optical discs have been commercialized, and the production of optical discs as a software supply source has also been advanced. Has been.

By the way, in the optical disc, a so-called compact disc for reproduction is widely used as a music recording medium. Therefore, if it is possible to reproduce such a compact disc in a computer, it is considered that the spread of multimedia will be further promoted.

However, since the magneto-optical disc recording / reproducing system and the compact disc reproducing device mounted on the computer have different disc chucking mechanisms, this is the reason why the compact disc is applied to the computer. It's difficult.

That is, in a recording / reproducing system for a magneto-optical disk mounted on a computer, it is necessary to access the optical disk at a higher speed than a reproducing apparatus for a compact disk which only reproduces music for the purpose of the computer. It is rotated at a rotation speed that is 2 to 3 times that of a disc reproducing apparatus. Therefore, the disc chucking mechanism of the magneto-optical disc recording / reproducing system is provided with a metal center hub for the optical disc so that the disc eccentricity does not occur even at such a high speed rotation. A hub chucking method is adopted in which an optical disk is fixed on the disk table by chucking and holding the disk table.

FIG. 15 shows an example of a chucking mechanism of the recording / reproducing system for the magneto-optical disk. This chucking mechanism has a disk table 102 attached to the tip side of a spindle shaft 101 that is rotated by a spindle motor. The disk table 102 is provided with a magnet 103, and the mounting portion 1 on which the disk 104 is mounted on the upper surface on the peripheral side.
05 is protruded.

On the other hand, the optical disc 104 fixed to the disc table 102 has a structure in which a recording portion is formed on a transparent substrate, and has a disk shape with a spindle bearing hole 106 having a diameter of 4 mm formed in the central portion. It has a metal center hub 107.

To fix the disc 104 to the disc table 102, while inserting the spindle shaft 101 into the spindle bearing hole 106 of the center hub 107,
The optical disc 104 is placed on the placing section 105. As a result, the center hub 107 is magnetically attracted to the magnet 103 of the disc table 102, and the disc 10
4 will be fixed on the disc table 102.

Therefore, as a condition for applying the optical disk to the recording / reproducing apparatus for the magneto-optical disk adopting the chucking mechanism, the optical disk has a center hub for chucking and holding the disk table. Is an essential condition. However, the compact discs that have already become widespread are not configured to support the hub chucking method as described above, and the center portion is fitted with a centering member for centering operation in the compact disc reproducing apparatus. Only the center hole is provided. Therefore, in reality, it cannot be applied to the recording / reproducing apparatus for the magneto-optical disk.

In view of the above conventional circumstances, driving of an optical disk which enables application of an optical disk having no center hub such as a compact disk to a recording / reproducing apparatus for a magneto-optical disk mounted on a computer. As a method and a center hub for an optical disc,
Japanese Patent Laid-Open No. 6-60511 has been proposed. The proposed center hub is made of metal magnetic material, magnetic chucking part that is held by magnetic attraction on the disk table, and plastic material, which is detachably fitted to the center hole of the optical disk. It is equipped with a mounting part.

[0012]

As described above, in Japanese Patent Laid-Open No. 6-60511, a center hub provided with a magnetic chucking portion made of a metallic magnetic material is detachably attached to an optical disk, and The chucking portion is magnetically attracted and held by chucking.

However, according to this method, a material having a hardness lower than that of the substrate material of the optical disc, that is, according to the published patent publication of the above-mentioned application, an insertion portion which is detachably fitted into the center hole of the optical disc is formed. In addition, it requires two points of parts that are magnetically attracted to the disk table by magnetic attraction and chucked and held.

Further, there is a method for integrally fastening the above-mentioned two parts, for example, a method in which the mounting portion and a disk-shaped metallic magnetic material for chucking are realized by adhesion. There is also a risk of parts coming off.

Further, due to the problem of securing the bonding accuracy of the two parts, when the optical disk in which this group of parts is inserted is rotated at high speed, disk eccentricity may occur and inconvenience may occur in accurate signal exchange. there is. For the same reason, the disc surface vibrates and the disc contacts the inside of the disc cartridge, causing abrasion inside the disc cartridge, and this abrasion powder may adhere to the disc to damage the disc.

[0016] Two parts, that is, an insertion part that is detachably fitted into the center hole of the optical disk with a plastic material, and a part for holding the chuck by magnetic attraction to the disk table with a metal magnetic material. It is a high-priced disc cartridge because it requires two steps and a fastening method.

Further, the center hub inserted into the center hole of the disc may fall off from the center hole.

Therefore, according to the present invention, the above-mentioned two parts are integrally made of a magnetic metal material so that they can be easily manufactured, and the center hub can be surely prevented from coming off from the disk. It was proposed for the purpose of supplying a quality and inexpensive disc cartridge.

[0019]

In order to solve the above-mentioned conventional problems and to achieve the object of the present invention, the present invention attaches a center hub to the center hole of an optical disk substrate, and a hub chucking mechanism is formed by the center hub. In an optical disk in which a recording / reproducing apparatus for a magneto-optical disk has a hub chuck and is rotated, the center hub is made of a magnetic material and has a cylindrical shape with a bottom, and a spindle bearing hole is provided in the center of the bottom plate. A center hole insertion portion that is inserted into the center hole of the optical disc substrate, and is integrally formed with one end portion of the center hole insertion portion.
The center hole insertion part is provided with a flange-shaped annular part that is superposed on the surface of the optical disc substrate when the center hole insertion part is inserted into the center hole. By providing an optical disk substrate sandwiching means projecting to the outer peripheral surface side and sandwiching the peripheral portion of the center hole of the optical disk substrate with the annular portion, the optical disk substrate sandwiching means allows the center of the center hole to be removed from the center hole. The hub was prevented from coming off, and the two were inseparably integrated. With the center hub, the recording / reproducing apparatus for the magneto-optical disk can be hub-chucked and rotated at the same high speed as the magneto-optical disk like the magneto-optical disk capable of recording and reproducing the optical disk. I did it.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an optical disc of the present invention will be described with reference to the drawings. FIG. 1 is an exploded perspective view of the optical disc 1. The optical disc 1 includes an optical disc substrate 2, a center hub 4 attached to a center hole 3 of the optical disc substrate 2, and an optical disc substrate holding means 5 for preventing the center hub 4 from slipping out of the center hole 3. 15 and the center hub 4 described above is used.
The recording / reproducing apparatus for magneto-optical disk as shown in FIG. 2 can be hub-chucked.

The optical disk substrate 2 is made of a transparent plastic such as polycarbonate and has a reflective film, a protective film, etc. on the surface thereof, and the center hole 3 in the center thereof.

The center hub 4 is provided with a cylindrical center hole insertion portion 11 and a flange-shaped circular ring portion 12 which is connected to the upper end of the center hole insertion portion 11. The hole insertion portion 11 and the annular portion 12 are integrally formed of a magnetic material such as iron.

The center hole insertion portion 11 is formed in a so-called bottomed cylindrical shape, and has a flat bottom plate 13 at the lower end.
And a spindle bearing hole 14 is provided in the center of the bottom plate 13. Further, notched window portions 15 ... 15 are formed on the peripheral surface of the center hole insertion portion 11 so as to project the bent portions 7 ... 7 of the optical disk substrate sandwiching means 5 described later.

The center hub 4 has a thickness of 0.2, for example.
mm-0.4 mm flat magnetic metal such as SUS430
Is easily formed by molding by a method such as pressing. Here, the size and shape of each part of the center hub 4 are set as follows. As shown in FIGS. 6 to 7, the outer diameter A of the center hole insertion portion 11 on the upper end side (the annular portion 12 side) is slightly larger than the inner diameter B of the center hole 3, for example, the center hole. 0.2m than inner diameter B of 3
It is set to be large by about m to 0.5 mm. By setting the outer diameter A of the center hole insertion portion 11 to the value as described above, when the center hole insertion portion 11 is inserted into the center hole 3, the center hole insertion portion 11 has an appropriate size. Due to the bending, a clamping force is generated between the outer peripheral surface of the center hole insertion portion 11 and the inner peripheral surface of the center hole 3, so that the center hub 4 is securely fixed to the optical disk substrate 2.

The outer peripheral surface of the center hole insertion portion 11 is a rough surface, that is, a ten-point average roughness (R _Z ) of 5 μm to 2 μm.
When the center hole insertion part 11 is inserted into the center hole 3, the frictional force is generated between the outer peripheral surface of the center hole insertion part 11 and the inner peripheral surface of the center hole 3 when the center hole insertion part 11 is inserted into the center hole 3. Then, the center hub 4 is securely fixed to the optical disk substrate 2. If the surface roughness (R _Z ) is 5 μm or less, the frictional force between the center hole insertion portion 11 and the center hole 3 may be insufficient, and the stability during rotation may be impaired. When the surface roughness (R _Z ) is 25 μm or more, the inner peripheral surface of the center hole 3 may be scraped when the center hole insertion portion 11 is inserted into the center hole 3.

The outer diameter C on the lower end side (bottom plate 13 side) of the center hole insertion portion 11 is slightly larger than the outer diameter A on the upper end side, for example, 0.1 to 0 from the outer diameter A. It is set to be large by about 0.3 mm. Therefore, the center hole insertion part 11 is arranged from the lower end side (bottom plate 13 side) to the upper end side (annular part 1).
2 side), it has a conical shape with an inclination angle θ that gradually becomes smaller toward the optical disk substrate 2 with the peripheral surface of the conical shape when being inserted into the center hole 3.
Is pressed upward to press the upper surface of the optical disk substrate 2 against the lower surface of the annular portion 12 to play an auxiliary role of the optical disk substrate sandwiching means 5 and to connect the optical disk substrate 2 and the center hub 4. Has become even stronger.

The height H from the lower surface of the annular portion 12 of the center hub 4 to the lower surface of the bottom plate 13 is used in a recording / reproducing apparatus for a magneto-optical disk to which the optical disk 1 of the present invention is applied. The height of the center hub is set to be approximately the same as that specified for the magneto-optical disk. For example, in the case of a center hub that is inserted into a compact disc (CD), the height H is 15.5 mm,
The outer diameter A is about 24 mm.

Next, the optical disk substrate clamping means 5 will be described. The optical disk substrate sandwiching means 5 is formed in a substantially equilateral triangle shape by bending a linear material having excellent elasticity and strength such as a piano wire (steel wire). The optical disk substrate sandwiching means 5 formed by bending the linear material into a substantially equilateral triangle has a gap C between both ends of the linear material.
Is generated so that the diameter can be reduced.

The optical disk substrate clamping means 5 is in a reduced diameter state, and the center hole insertion portion 1 of the center hub 4 is
1 is inserted. The positions of the bent portions 7 ... 7 of the optical disk substrate clamping means 5 are set to the center hole insertion portion 11
15 is aligned with the positions of the cutout window portions 15 provided on the peripheral surface of the optical disc substrate, and the force that reduces the diameter of the optical disc substrate clamping means 5 is released, the optical disc substrate clamping means 5 has its own spring. The diameter is expanded by force, and as shown in FIGS. 2 to 5, the bent portions 7 ... 7 enter the cutout window portions 15 ... 15, and the center is passed through the cutout window portions 15 ... 15. The center hole 4 projects from the outer peripheral surface of the hole insertion portion 11 to hold the peripheral edge of the center hole 3 of the optical disk substrate 2 between the ring insertion portion 12 and the center hole 4, and the center hole 4 falls off from the center hole 3. It is designed to prevent

8 to 10 show modifications of the optical disk substrate holding means 5. In the first modification shown in FIG. 8, the bent portions 7 are formed by forming the bent portions 7 ... 7 in a circular shape.
... 7 is improved in the sandwiching effect and the drop-out preventing effect. Further, in the second modified example shown in FIG. 9, by forming the optical disk substrate holding means 5 in a quadrangular shape,
7 shows the case where the optical disk substrate 2 is sandwiched between the four bent portions 7 ... 7 and the annular portion 12. In the embodiment shown in FIG. 10, by forming the optical disk substrate holding means 5 into a pentagonal shape, five bent portions 7 ... 7 and an annular portion 12 are formed.
The case where the optical disk substrate 2 is sandwiched between the two is shown. In the case of FIGS. 9 to 10, the center hole insertion portion 11 is formed with the same number of notched window portions 15 ... 15 as the number of the bent portions 7 ... 7. The optical disk clamping means 5 is not limited to the one described above, and any means may be used as long as it can reliably clamp the optical disk substrate 2 with the annular portion 12.

As shown in FIGS. 1 and 11, the optical disk substrate 2 and the center hub 4 are engaged with each other when the center hub 4 is inserted into the center hole 3 so that the center hole 3 can be engaged with the center hub 3. A protrusion 21 and a protrusion engaging portion 22 that prevent the hub 4 from idling are provided. The protrusion 21
Is formed by projecting the annular portion 12 of the center hub 4 into a cylindrical shape, and the protrusion engaging portion 22
Are formed by providing circular holes and grooves on the upper surface of the optical disc substrate 2.

Then, the center hole 3 of the optical disc substrate 2
Insert the center hole insertion part 11 of the center hub 4 into the
When the lower surface of the annular portion 12 of the center hub 4 is overlapped with the upper surface of the optical disc substrate 2, the protrusion 21 fits into the protrusion engaging portion 22, and the optical disc substrate 2 and the center hub 4 are joined together.
It is designed to prevent the relative rotation of the. The protrusion 21
Is formed at the same time when the center hub 4 is molded by providing the press die with a projection for forming a protrusion when the center hub 4 is pressed. The protrusion engaging portion 22 is provided in the mold for forming the optical disk substrate and has the center hole 3
By performing the same processing as that for forming the optical disk substrate, the optical disk substrate and the optical disk substrate are simultaneously formed.

FIG. 12 shows the protrusion 21 and the protrusion engaging portion 22.
The 1st modification of is shown. In this modification, the protrusion 21 is formed on the outer peripheral surface of the center hub 4, and the protrusion engaging portion 22 is formed on the inner peripheral surface of the center hole 3 of the optical disc substrate 2.

Then, the center hole inserting portion 11 is inserted into the center hole 3 in a state where the positions of the protrusion 21 and the protrusion engaging portion 22 are aligned.

FIG. 13 shows the protrusion 21 and the protrusion engaging portion 22.
The 2nd modification of is shown. In this modification, the protrusion 2
1 is provided on the optical disk substrate 2, and the projection engaging portion 22 is formed by providing a hole or groove in the annular portion 12 of the center hub 4.

Then, the center hole insertion portion 11 of the center hub 4 is inserted into the center hole 3 of the optical disk substrate 2, and the lower surface of the annular portion 12 of the center hub 4 is superposed on the upper surface of the optical disk substrate 2. Then, the projection 21 is fitted into the projection engaging portion 22 to prevent relative rotation of the optical disk substrate 2 and the center hub 4. The protrusion 21 is formed integrally with the optical disc substrate 2 when the optical disc substrate 2 is formed, and the protrusion engagement portion 22 is formed integrally with the center hub 4 when the optical disc substrate 2 is formed.

As shown in FIG. 14, the optical disk substrate 2
A chamfered portion 31 is formed in the peripheral portion of one end of the center hole 3 on the upper surface side (the surface that contacts the annular portion 12 of the center hub 4). When the center hub 4 is formed by pressing a metal plate, a bulging portion 32 is generated at the root of the annular portion 12 due to the deformation strain, and the bulging portion 32 causes the annular portion 12 to form the optical disk substrate. It becomes an obstacle when stacking on 2.

The chamfered portion 31 accommodates the bulging portion 32 when the center hub 4 is inserted into the optical disc substrate 2, and the bulging portion 32 superimposes the annular portion 12 on the optical disc substrate 2. The center hub 4 can be accurately attached to the optical disc substrate 2 so as not to become an obstacle.

The chamfered portion 31 is formed simultaneously with the molding of the optical disc substrate 2.

[0040]

The optical disk of the present invention has the following effects.

(1) In the optical disc of claim 1, the center hub is attached to a read-only optical disc substrate such as a compact disc or a CD-ROM. Therefore, the center hub is attached to a recording / reproducing system such as a computer. When applied to the recording / reproducing device for magneto-optical discs installed in, the disk chuck will be held by hub chucking, and the optical disc will be securely held on the turntable to obtain stable and reliable high-speed rotation characteristics. You can In particular, since the center hub is integrally formed of a magnetic material, the cost can be reduced as compared with the conventional center hub assembled with two parts, and the center hub has excellent durability.

Further, since the upper and lower surfaces of the peripheral edge of the center hole of the optical disk substrate are sandwiched between the annular portion of the center hub and the optical disk clamping means attached to the center hub, the optical disk substrate and the center hub are not coupled. This ensures reliability and prevents the center hub from falling off the optical disk substrate.

(2) In the optical disc of claim 2,
The optical disk substrate holding means formed by bending a linear material having elasticity into a polygonal shape is reduced in diameter and inserted into the center hole insertion portion of the center hub, and then expanded in diameter to insert the bent portion into the center hole. The optical disc substrate can be reliably sandwiched between the annular portion of the center hub and the simple configuration of protruding from the cutout window portion provided in the attachment portion and the easy operation.

(3) In the optical disc of claim 3,
Since the optical disc substrate is provided with a protrusion engaging portion such as a small hole or a notch that engages with the protrusion of the center hub integrally formed of a magnetic material, the center hub engaged during rotation is It is maintained without idling in.

(4) In the optical disc of claim 4,
Since the optical disc substrate is provided with a protrusion and a protrusion engaging portion such as a small hole or a notch that engages with the protrusion of the center hub integrally formed of a magnetic material is provided, the center hub engaged during rotation can be , It is maintained in the center hole without spinning.

[Brief description of drawings]

FIG. 1 is an exploded perspective view.

FIG. 2 is a perspective view of an assembled state.

FIG. 3 is a perspective view seen from the bottom side.

FIG. 4 is a plan view of a main part.

FIG. 5 is a sectional view taken along line AA of FIG. 4;

FIG. 6 is a sectional view of an optical disk substrate and a center hub.

FIG. 7 is a sectional view of the inserted state.

FIG. 8 is a plan view of a modified example of the optical disk substrate clamping means.

FIG. 9 is a plan view of a modified example of the optical disk substrate holding means.

FIG. 10 is a plan view of a modified example of the optical disk substrate holding means.

FIG. 11 is a perspective view of a protrusion and a protrusion engaging portion.

FIG. 12 is a perspective view of a modification.

FIG. 13 is a perspective view of a modified example.

FIG. 14 is an enlarged sectional view of a chamfered portion.

FIG. 15 is a sectional view of a conventional example.

[Explanation of symbols]

1 ... Optical disc, 2 ... Optical disc substrate, 3 ... Center hole, 4 ... Center hub, 5 ... Optical disc substrate clamping means,
Reference numeral 7 ... Bent portion, 11 ... Center hole insertion portion, 12 ... Flange ring portion, 13 ... Bottom plate, 14 ... Spindle bearing hole,
21 ... Projection, 22 ... Projection engaging part, 31 ... Chamfer part.

Claims (4)

[Claims] 1. A recording / recording device for a magneto-optical disc having a hub chucking mechanism by attaching a center hub to a center hole of an optical disc substrate and using the center hub.
In an optical disk adapted to be hub-chucked to a reproducing device for rotation, the center hub has a cylindrical shape with a bottom made of a magnetic material, and has a spindle bearing hole in the center of the bottom plate, and the center hole of the optical disk substrate. A center hole insertion portion to be inserted into the center hole insertion portion, and one end portion of the center hole insertion portion integrally formed with the center hole insertion portion. When the center hole insertion portion is inserted into the center hole, the optical disc is inserted. The center hub is provided with a flange-shaped annular portion that is superposed on the surface of the substrate, and the center hub projects toward the outer peripheral surface side of the center hole insertion portion, and the center hub of the optical disc substrate An optical disk comprising an optical disk substrate clamping means for clamping the peripheral portion of the center hole. 2. The cutout window according to claim 1, wherein the optical disk substrate holding means is formed by bending a linear material having elasticity into a polygonal shape, and the bent portion is provided in the center hole inserting portion. An optical disc, characterized in that it is formed by projecting from the inner peripheral surface side to the outer peripheral surface side of the center hole insertion portion through the portion. 3. The optical disc substrate and the center hub according to claim 1, wherein the optical disc substrate has a protrusion and a protrusion engaging portion that engage with each other when the center hub is inserted into the optical disc substrate and prevent rotation of the center hub with respect to the optical disc substrate. Playing optical disc. 4. The protrusion and the protrusion engaging portion according to claim 3, wherein the protrusion is provided on a peripheral portion of a center hole of the optical disk substrate, and the center hub is provided with a recess into which the protrusion is fitted. Optical disc.