JPH05325466A - Method and device for attaching magnetic plate to disk substrate - Google Patents

Abstract

(57) [Summary] [Construction] In the state where the magnetic plate 5 is provided with a constant space H between the magnetic plate 5 and the bottom surface 6a of the magnetic plate storage recess 6 provided in the center of the disk substrate 2, the magnetic plate storage recess 6 is formed. The horn 17 is brought into contact with the peripheral edge of the magnetic plate and ultrasonically processed to form a protruding portion 19 protruding from the peripheral edge of the magnetic plate housing concave portion 6 toward the inside of the concave portion 6. [Effect] The magnetic plate can be housed and held in a loosely fitted state with a fixed clearance with respect to the disk substrate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mounting method and a mounting device for a magnetic plate disposed on a disk substrate which constitutes an information signal recording disk such as an optical disk or a magneto-optical disk in which desired information signals are recorded. ..

[0002]

2. Description of the Related Art Conventionally, discs for recording information signals, such as optical discs and magneto-optical discs, on which desired information signals are recorded have been proposed. This type of disc is capable of high density recording of information signals, so that a disc having an extremely small diameter has been proposed. For example, there has been proposed an optical disk or a magneto-optical disk having a diameter of about 64 mm and capable of recording a music signal for about 74 minutes.

The magneto-optical disk having such a small diameter and capable of high-density recording of information signals is mounted on a disk rotation driving device and rotated at a high speed. Then, while being driven to rotate at a high speed, a fine recording track provided on the signal recording layer formed on one main surface of the magneto-optical disk is irradiated with a light beam emitted from the optical pickup device, and a magnetic field is generated. A desired information signal is recorded by applying an external magnetic field that is magnetic field modulated according to the information signal to be recorded from an external magnetic field generator such as a head.

In order to accurately irradiate a fine recording track with a light beam while being rotationally driven at such a high speed,
The magneto-optical disk is required to be securely integrated with the disk table of the disk rotation driving device and to be mounted with the rotation center positioned with high accuracy on the axis of the disk table. In order to achieve such an object, conventionally, a metal plate made of a magnetic material is arranged on the side of the magneto-optical disk, and this is attracted by a magnet provided on the side of the disk table. A disk mounting method has been proposed in which the disk is chucked upward.

The magneto-optical disk used in the magnet chucking system utilizing the attractive force of this magnet is
As shown in FIG. 10, a disk substrate 51 formed by molding a transparent synthetic resin such as a polycarbonate resin into a disk shape is provided. An information signal recording layer on which a desired information signal is recorded is formed on one main surface 51a side of the disc substrate 51. Then, the disc substrate 51
Defines the other main surface 51b opposite to the one main surface 51a on which the information signal recording layer is formed as an information signal writing / reading surface, and irradiates the signal recording layer with a light beam from this writing / reading surface side. Recording or reproduction of a desired information signal is performed.

A center hole 52 is formed in the center of the disk substrate 51 so that a centering member provided on the disk rotation drive side can engage with the center hole 52. Further, a disk-shaped magnetic plate 53 made of a metallic material is disposed in the center of the one main surface 51a side of the disk substrate 51 so as to close the center hole 52. The magnetic plate 53 is arranged so as to fit into a magnetic plate storage recess 54 formed on the one main surface 51a side of the disk substrate 51 so as to surround the center hole 52. And
The magnetic plate 53 disposed in the magnetic plate storage recess 54 is formed by the protrusion 55 that is formed so as to project inward of the recess 54 by ultrasonically processing the peripheral edge of the magnetic plate storage recess 54. The disc substrate 51 is housed and held.

The attachment of the magnetic plate 53 to the disk substrate 51 is performed as follows. First, as shown in FIG. 10, the disc substrate 51 is positioned and placed on the disc receiving base 56. The above disk cradle 5
Reference numeral 6 denotes a magnetic plate storage recess 5 provided on the disk substrate 51.
4 has a disk receiving portion 57 for accommodating the disk substrate 51 by accommodating the projecting portion 59 projecting from the outer periphery of the disk 4, and by accommodating the projecting portion 59 in the disk receiving portion 57, The substrate 51 is positioned.

Next, a cylindrical horn 58 is brought into contact with the opening peripheral edge of the magnetic plate accommodating recess 54 of the disc substrate 51 placed on the disc receiving portion 57, and ultrasonic waves from an ultrasonic oscillator (not shown) are generated. Vibration is transmitted to this horn 58. As a result, as shown in FIG. 11, the peripheral edge of the opening of the magnetic plate accommodating recess 54 is thermally deformed, and the resin in the peripheral edge of the opening is pressed by the pressure applied by the depression of the horn 58.
An annular protrusion 55 is formed so as to project inward. As a result, the magnetic plate 53 is housed and held in the magnetic plate housing recess 54 in a loosely fitted state.

[0009]

By the way, as described above, in order to accommodate and hold the magnetic plate 53 in the loosely fitted state, the variation in the sinking amount Ha of the horn 58 and the thickness Hb of the protruding portion 55 is varied. It is necessary to swage with consideration. Therefore, swaging must be performed under a narrow condition width, and when the allowable range is exceeded even slightly, the magnetic plate 53 is loosely fitted in the disk substrate 51.
Difficult to hold. In the worst case, the magnetic plate 53 may be fixed to the disk substrate 51. When the magnetic plate 53 is fixed to the disk substrate 51, the disk substrate 2 may be deformed due to the difference in thermal expansion coefficient between the magnetic plate 58 made of these metal materials and the disk substrate 51 made of synthetic resin. As a result, birefringence occurs in the disk substrate 51, and there is a risk that writing or reading of an information signal may be defective due to deterioration of optical characteristics.

Therefore, the present invention has been proposed in view of the above technical problem, and the magnetic plate can be housed and held in a loosely fitted state with a certain clearance with respect to the disk substrate. An object of the present invention is to provide a method for attaching a magnetic plate to a disc substrate, which is capable of attaching the magnetic plate to the disc substrate under a wide range of conditions.

A further object of the present invention is to provide a device for attaching a magnetic plate to a disk substrate, which allows the magnetic plate to be housed and held in a loosely fitted state with a fixed clearance with respect to the disk substrate.

[0012]

In order to achieve the above-mentioned object, the present invention provides a state in which a magnetic plate is provided with a constant space between the magnetic plate and the bottom surface of a magnetic plate accommodating recess provided in the center of a disk substrate. Then, the ultrasonic wave generating means is brought into contact with the peripheral edge of the magnetic plate accommodating concave portion to form a projecting portion projecting inward from the peripheral edge of the magnetic plate accommodating concave portion. The magnetic plate is attached to the disk substrate.

Further, according to the mounting apparatus of the present invention, there is provided a disk mounting means having a projecting portion facing the center hole of the disk substrate and projecting from the bottom surface of the recess for storing the magnetic plate of the disk substrate, and the magnetic plate is mounted on the projecting portion. In a state of being placed, it is provided with an ultrasonic wave generating means that abuts on the peripheral edge of the magnetic plate accommodating recess and thermally deforms the peripheral edge of the magnetic plate accommodating recess.

[0014]

In the method according to the present invention, when the magnetic plate is accommodated and held in the magnetic plate accommodating recess provided in the center of the disk substrate in a loosely fitted state, the magnetic plate accommodating recess is spaced from the bottom surface of the magnetic plate accommodating recess by a certain distance. Since the magnetic plate is ultrasonically processed in a floating state, even if a protrusion formed by thermal deformation by ultrasonic processing hits the magnetic plate, the gap is not eliminated. Therefore, a constant clearance is surely provided between the magnetic plate and the disk substrate.

On the other hand, in the apparatus according to the present invention, the disk mounting means for mounting the disk substrate is provided with a projecting portion that faces the center hole of the disk substrate and projects from the bottom surface of the magnetic plate accommodating recess of the disk substrate. Therefore, by mounting the magnetic plate on the protruding portion, a certain clearance is provided between the magnetic plate and the disk substrate.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments to which the present invention is applied will be described in detail below with reference to the drawings. The present embodiment is an example in which the present invention is applied to a magneto-optical disk having a diameter of 64 mm. First, a magneto-optical disk to which the present invention is applied will be described. Such a magneto-optical disk 1
As shown in FIG. 1, the disk substrate 2 is formed by integrally molding a transparent synthetic resin material such as a polycarbonate resin. The disc substrate 2 has a diameter of about 64 mm and is formed in a disk shape with a thickness of about 1.2 mm.

A magneto-optical disc 1 constructed by using this disc substrate 2 has one main surface 2 of the disc substrate 2.
It has a signal recording part formed with an information signal recording layer for recording a desired information signal on the a side, and the other main surface 2b on the opposite side is used as a writing / reading surface of the information signal, and The information signal is recorded / reproduced by irradiating the signal recording layer with a light beam from the writing / reading surface side.

As shown in FIG. 2, the central portion of the disc substrate 2 constituting the magneto-optical disc 1 is arranged at the central portion of the disc table constituting the disc rotation driving device arranged in the recording / reproducing apparatus. A center hole 3 is formed in which a provided centering member (not shown) is engaged. The center hole 3 is formed as a circular hole penetrating the disk substrate 2, and the center of the center hole 3 coincides with the center of curvature of a recording track formed concentrically or spirally on the signal recording layer. It is formed to let.

The other main surface 2 of the disk substrate 2
An annular projecting portion 4 is integrally formed in the center portion on the b side so as to surround the center hole 3. This protrusion 4
The center hole 3 of the centering member arranged on the side of the disk table on which the magneto-optical disk 1 is mounted, without increasing the depth of the center hole 3 formed in the thin disk substrate 2. The amount of protrusion with respect to is increased, and the centering operation for mounting the magneto-optical disk 1 with the rotation center of the magneto-optical disk 1 aligned with the axis of the disk table is performed reliably. further,
The tip surface 4a of the protruding portion 4 functions as a reference surface for mounting on the disc table.

The protrusion 4 is formed at least in the non-signal recording area on the inner peripheral side of the disc substrate 2 where the signal recording layer is not formed, and protrudes with a protrusion amount substantially equal to the thickness of the disc substrate 2. Has been formed. Therefore, the portion of the disk substrate 2 on which the protruding portion 4 is formed is about twice as thick as the substrate body portion.

At the center of the one main surface 2a side of the disk substrate 2, there is formed an annular magnetic plate accommodating recess 6 in which a magnetic plate 5 for magnet attraction is arranged so as to surround the center hole 3. Has been formed. The magnetic plate accommodating recess 6 has a diameter smaller than the outer peripheral diameter of the protrusion 4, and the disk substrate 2
Is formed to a depth approximately equal to the thickness of. Further, the inner diameter of the opening of the magnetic plate housing recess 6 is larger than the diameter of the center hole 3. Therefore, an annular flat surface 6a is provided at the bottom of the magnetic plate storage recess 6. The flat surface 6a serves as a mounting surface on which the magnetic plate 5 is mounted.

On the other hand, the magnetic plate 5 accommodated and held in the magnetic plate accommodating recess 6 is formed by punching a metal material such as a stainless plate into a disc shape. The magnetic plate 5 is formed as a disk having a size large enough to be stored in the magnetic plate storage recess 6, and when the magnetic plate 5 is stored and held in the magnetic plate storage recess 6, the outer peripheral surface 5a thereof is the magnetic plate. It is formed in such a size that it does not come into contact with the inner peripheral wall 6b of the storage recess 6. Also, this magnetic plate 5
A small circular hole 7 used for handling in the manufacturing process is formed in the center of the.

The magnetic plate 5 formed as described above is attached to the disk substrate 2 by an attaching device having an ultrasonic wave generating means described below. As shown in FIG. 3, such a mounting device includes a disk substrate supporting table 8 which is a disk mounting means for mounting the disk substrate 2 and an ultrasonic wave generating means which is an ultrasonic wave generating means for applying an ultrasonic wave to the disk substrate 2. It is composed of a mechanical section 9.

The disk substrate support table 8 is constructed so as to position the mounted disk substrate 2, and the support table body 1 has a flat plate shape.
On the upper surface side of 0, a disk substrate mounting table 11 for positioning and mounting the disk substrate 2 is provided. As shown in FIGS. 4 and 5, the disc substrate mounting table 11 has a fitting protrusion 12 which is a protrusion into which the center hole 3 of the disc substrate 2 fits, as shown in FIGS. A protrusion fitting recess 13 is formed around the outer periphery of the joint protrusion 12 to allow the protrusion 4 of the disk substrate 2 to be fitted loosely.

The fitting protrusion 12 is formed as a columnar protrusion having an outer diameter substantially the same as the opening diameter of the center hole 3, and the inside of the magnetic plate accommodating recess 6 from the center hole 3 of the disk substrate 2. The magnetic plate housing concave portion 6 is slightly protruded from the bottom surface 6a. The height H of the fitting projection 12 that projects from the bottom surface 6a of the magnetic plate storage recess 6 is a constant clearance C required to hold the magnetic plate 5 in the magnetic plate storage recess 6 in a loosely fitted state. And the thickness T of the magnetic plate 5 are summed. In addition, an inclined surface 14 is formed on the peripheral edge of the fitting protrusion 12 on the tip side.
Is provided so that the disc substrate 2 can be easily inserted into the fitting projection 12.

The projection fitting recess 13 provided on the outer periphery of the fitting projection 12 is formed as an annular recess sufficient to accommodate the projection 4 of the disk substrate 2 therein. When the protruding portion 4 is stored, the inner peripheral wall 1 thereof is
A predetermined gap is formed between 3a and the outer peripheral surface 4b of the protrusion 4. Therefore, the disc substrate 2 is positioned on the disc substrate mounting table 11 by fitting the center hole 3 into the fitting protrusion 12. In the state where the disc substrate 2 is positioned, the tip end surface 4a of the protrusion 4 of the disc substrate 2 is supported by the bottom surface 13b of the protrusion fitting recess 13 and the upper end surface 11a of the disc substrate mounting table 11 is A main surface 2b, which is a writing / reading surface for information signals of the disk substrate 2, is supported. The disk substrate supporting table 8 configured as described above includes the disk substrate mounting table 11
In order to securely fix the disc substrate 2 placed on the
A suction mechanism (not shown) for vacuum suction using a vacuum pump is provided.

On the other hand, as shown in FIG. 3, the ultrasonic wave generation mechanism section 9 has an ultrasonic wave vibrator 15 which mainly converts electric energy generated from an ultrasonic wave oscillator into mechanical vibration.
And a cone 16 for amplifying the mechanical vibration of the ultrasonic transducer 15 and a horn 17 for propagating the amplified mechanical vibration to the workpiece. The ultrasonic transducer 15, the cone 16, and the horn 17 are integrated in a line in that order, and by an air cylinder 18,
It is adapted to move up and down with respect to the disk substrate 2. A control board is provided between the disc substrate support table 8 and the ultrasonic oscillator, and the disc substrate 2
The pressing force of the horn 17, the amount of amplitude, and the swaging depth are controlled.

In order to hold the magnetic plate 5 in the disk substrate 2 in a loosely fitted state by using the above-mentioned mounting device, the following procedure is carried out. First, as shown in FIG. 4, the disk substrate 2 is mounted on the disk substrate mounting table 11. That is,
Fitting protrusion 1 provided on the disk substrate mounting table 11
The center hole 3 of the disk substrate 2 is fitted to the disk 2, and the projection 4 of the disk substrate 2 is housed and held in the projection fitting recess 13. As a result, the mounting position of the disc substrate 2 on the disc substrate mounting table 11 is determined.

After that, the disk substrate mounting table 11
By operating a suction mechanism built in the disk substrate 2 by vacuum suction, the disk substrate mounting table 11
Fix it on top.

Next, the magnetic plate 5 is put into the magnetic plate housing recess 6 of the disk substrate 2. As a result, the magnetic plate 5 is
As shown in FIG. 5, it is placed on the fitting projection 12 and is held in a state of floating with a predetermined height H from the bottom surface 13a of the projection fitting recess 13. Next, the horn 17 is lowered by the air cylinder 18, and as shown in FIG. 6, the tip 17a of the horn 17 is provided around the opening peripheral edge of the magnetic plate accommodating recess 6 of the main surface 2a of the disk substrate 2 on which the information signal recording layer is formed. Abut the part.

Then, ultrasonic vibration is applied to the disk substrate 2 while a predetermined pressure F is applied to the disk substrate 2 by the air cylinder 18.

Then, as shown in FIG. 7, the peripheral edge of the opening of the magnetic plate accommodating recess 6 with which the horn 17 is in contact is heated and softened. Then, the pressing force F applied to the horn 17 causes the opening peripheral portion of the magnetic plate housing recess 6 to form a recess corresponding to the size of the horn 17, as shown in FIG. It projects to the inner peripheral side of the plate storage recess 6.

As a result, as shown in FIG.
A protruding portion 19 is formed at a portion abutting against the inner peripheral side of the magnetic plate accommodating concave portion 6. Such protrusion 19
Is formed in an annular shape so as to cover the outer peripheral edge portion 5a of the magnetic plate 5 housed in the magnetic plate housing recess 6, and prevents the magnetic plate 5 from falling off the disk substrate 2. In addition, in such swaging, the protrusion 19 is formed on the magnetic plate 5.
Since it abuts against the upper end surface 5b of the, the thickness of the protrusion 19 is controlled with high accuracy.

After the swaging is completed, the horn 1
7 is lifted with respect to the disk substrate 2, vacuum suction is released, and the disk substrate 2 is taken out. As a result, as shown in FIG. 9, the magneto-optical disk 1 in which the magnetic plate 5 is held in the disk substrate 2 in a loosely fitted state is manufactured. Since the magneto-optical disk 1 is manufactured by swaging the magnetic plate 5 while preliminarily floating the magnetic plate 5 with respect to the disk substrate 2, the magnetic plate 5 and the protruding portion 19 formed so as to cover the magnetic plate 5 are formed. A certain clearance C is secured between them. That is, the magnetic plate 5 can be loosely fitted and held on the disk substrate 2 with a preset clearance C. As a result, it is possible to prevent the disk substrate 2 from being deformed due to the difference in thermal expansion coefficient between the disk substrate 2 made of synthetic resin and the magnetic plate 5 made of a metal material.

In the present embodiment, an example in which the present invention is applied to a magneto-optical disk has been described, but the present invention also has a disk substrate made of synthetic resin and a magnetic plate for magnet chucking. It is widely applicable to information signal recording discs having

[0036]

As is apparent from the above description, in the method of the present invention, the magnetic plate is magnetically suspended from the bottom surface of the recess for storing the magnetic plate so that a predetermined clearance can be secured in advance. Since the peripheral edge of the plate housing recess is ultrasonically processed, the magnetic plate can be housed and held in the magnetic plate housing recess in a loosely fitted state. Therefore, the magnetic plate can be prevented from being fixedly attached to the main surface of the disk substrate in a tilted manner, and the disk caused by the difference in thermal expansion coefficient between the disk substrate made of synthetic resin and the magnetic plate made of a metal material. The deformation of the substrate can be prevented. This allows
An information signal recording disk configured using this disk substrate can be stably mounted on the disk table of the disk rotation drive mechanism.

On the other hand, in the apparatus according to the present invention, since the disk mounting means for mounting the disk substrate is provided with the projecting part projecting from the bottom surface of the magnetic plate accommodating recess of the disk substrate, the magnetic plate is mounted on this projecting part. By mounting the disk, a certain clearance can be provided between the magnetic plate and the disk substrate. Therefore, swaging of the magnetic plate with respect to the disk substrate can be easily performed, and an information signal recording disk can be manufactured with high yield.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a magneto-optical disk to which the present invention is applied.

FIG. 2 is a cross-sectional view showing a disassembled state of a magneto-optical disk to which the present invention is applied.

FIG. 3 is a front view showing a magnetic plate attachment device to which the present invention is applied.

FIG. 4 is a cross-sectional view showing a state in which a magnetic plate is placed on the disc substrate.

FIG. 5 is an enlarged cross-sectional view of an essential part in a state where a magnetic plate is placed on the disc substrate.

FIG. 6 is a cross-sectional view showing a state where a horn is in contact with a disk substrate.

FIG. 7 is a cross-sectional view showing a swaging state.

FIG. 8 is an enlarged cross-sectional view of a main part in a swaging state.

FIG. 9 is a sectional view of the magneto-optical disk after swaging is completed.

FIG. 10 is a cross-sectional view showing a state of swaging by a conventional method.

FIG. 11 is an enlarged cross-sectional view of a main part in a swaging state according to a conventional method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Magneto-optical disk 2 ... Disk substrate 3 ... Center hole 5 ... Magnetic plate 6 ... Magnetic plate storage recess 8 ... Disk substrate support table 9 ... Ultrasonic wave generation mechanism part 11 ... Disk substrate mounting table 12 ... Fitting projection 15 ... Ultrasonic transducer 16 ... Cone 17 ... Horn 18 ... Air cylinder 19 ... Projection

Claims (2)

[Claims] 1. An ultrasonic wave generating means is brought into contact with the peripheral edge of the magnetic plate accommodating recess in a state in which the magnetic plate is spaced from the bottom surface of the magnetic plate accommodating recess provided in the center of the disk substrate. By forming the magnetic plate accommodating concave portion, a protrusion protruding from the peripheral edge of the magnetic plate accommodating concave portion toward the inside of the concave portion is formed, and the magnetic plate is attached to the disc substrate by the protruding portion. How to install. 2. A disk mounting means having a projecting portion facing the center hole of the disk substrate and projecting from the bottom surface of the magnetic plate accommodating concave portion of the disk substrate; and a magnetic plate mounted on the projecting portion. An apparatus for attaching a magnetic plate to a disk substrate, comprising: an ultrasonic wave generation unit that comes into contact with the peripheral edge of the magnetic plate storage recess and thermally deforms the peripheral edge of the magnetic plate storage recess.