JPH04258860A - Recording disk - Google Patents

Abstract

PURPOSE:To obviate the generation of a distortion in a disk substrate by the displacement of a film body even if a disk hub and the disk substrate thermally expands or contracts differently. CONSTITUTION:The disk hub 4 placed on the central part 5 of the disk substrate 1 is held onto this disk substrate 1 by depositing and forming a film body 7 consisting of a synthetic resin material on the main surface part of the disk hub 4 and the main surface part of the disk substrate 1 through.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording disk, such as a so-called optical disk or a magneto-optical disk, which serves as a recording medium for information signals.

0002

2. Description of the Related Art Conventionally, recording disks for recording and/or reproducing information signals, such as so-called optical disks and magneto-optical disks, have been proposed. As shown in FIG. 5, this recording disk has a disk-shaped disk substrate 101, and one main surface of this disk substrate 101 is configured as a signal recording surface 101a. This disk substrate 101 is made of a transparent synthetic resin material such as polycarbonate. A signal recording layer 101b made of a magnetic material film, a metal film, etc. is formed on the other main surface of the disk substrate 101. That is, information signals are written to and/or read from the signal recording layer 101b from one main surface of the disk substrate 101, which is the signal recording surface 101a, through the disk substrate 101 and into the signal recording layer 101b. This is done by irradiating a beam of light.

The central portion of this recording disk is a chucked portion 102 that is held by a so-called disk player device that writes and/or reads information signals to and from the recording disk. The chucked portion 102 has a center hole 103 provided in the center of the disk substrate 101, and a center hole 103 that closes the center hole 103 to cover the disk substrate 101.
A metal plate body 104 is attached to the other main surface of the metal plate 104. The center hole 103 is formed substantially concentrically and spirally on the signal recording surface 101a, with its center coinciding with the center of curvature of a recording track on which an information signal is written.

[0004]The recording disc is placed and held on a disc table 201 in the disc player device. This disk table 201 is formed into a disk shape with a larger diameter than the center hole 103, and is attached to a drive shaft 202a of a spindle motor 202. A truncated conical centering protrusion 203 having a diameter approximately corresponding to the center hole 103 is provided on the upper surface of the disc table 201 . A magnet (not shown) is provided within this centering protrusion 203.

When this recording disk is placed on the disk table 201 with the center side of one main surface in contact with the disk table 201, the recording disk is placed in the center hole 103. By fitting the centering protrusion 203, a so-called centering operation is performed in which the center of the center hole 103 is aligned with the center of the centering protrusion 203. Then, this recording disk has one main surface portion brought into contact with the upper surface portion of the disk table 201 by the metal plate body 104 being attracted by the magnet.
Retained.

[0006]

In the recording disk as described above, the metal plate 104 is attached to the disk substrate 101 by means such as bonding using an adhesive. Since this adhesive must adhere to both the synthetic resin material such as polycarbonate forming the disk substrate 101 and the metal material forming the metal plate 104, the types of adhesives that can be used are limited.

[0007] Furthermore, the synthetic resin material forming the disk substrate 101 and the metal material forming the metal plate 104 are as follows:
Since their coefficients of thermal expansion differ from each other, when the environmental temperature changes,
Easy to cause peeling. On the other hand, if the disk substrate 101 and the metal plate 104 are firmly attached so as not to cause peeling, changes in the environmental temperature may cause the disk substrate 101 to
Distortion may occur in the disk substrate 101, and so-called birefringence may occur within the disk substrate 101. If birefringence occurs within the disk substrate 101, it is impossible to write and/or read information signals favorably to the signal recording layer 101b.

Therefore, the present invention is proposed in view of the above-mentioned circumstances, and the present invention is such that a plate made of a material different from that of the disk substrate is securely attached to the disk substrate, and the disk is prevented from changing due to changes in environmental temperature or the like. It is an object of the present invention to provide a recording disk in which distortion is prevented from occurring in the substrate.

[0009]

[Means for Solving the Problems] In order to solve the above problems and achieve the above objects, a recording disk according to the present invention has at least one main surface serving as a signal recording surface and a through hole provided in the center. a disk substrate; a plate body formed of a material different from the disk substrate and placed on one main surface of the disk substrate with the through hole closed; and a side of the plate body that abuts the disk substrate; A membrane body is formed over the main surface portion of the opposing side and the main surface portion of the disk substrate on which the plate body is placed, and holds the plate body on the disk substrate. .

0010

[Operation] In the recording disk according to the present invention, the plate formed of a material different from the disk substrate and placed on one main surface of the disk substrate is opposite to the side of the plate that comes into contact with the disk substrate. Since it is held on the disk substrate by a film formed over the main surface of the disk substrate on which the plate is placed and the main surface of the disk substrate on which the plate is placed, changes in the environmental temperature do not occur. Also, the displacement of the film body does not cause distortion in the disk substrate.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the present invention will be described below with reference to the drawings. In this example, the recording disk according to the present invention is configured as a so-called magneto-optical disk.

This recording disk is constructed with a disk substrate 1, as shown in FIGS. 1 and 3. As shown in FIGS. The disk substrate 1 is formed into a disk shape from a material such as a transparent synthetic resin such as polycarbonate. One main surface of the disc substrate 1 serves as a signal recording surface 1a on which information signals are written and/or read by the disc player. On the other main surface of the disk substrate 1, a signal recording layer 2 made of a magnetic material is adhered. That is, writing and/or reading of information signals to and from the signal recording layer 2 is performed using the disk substrate 1.
This is carried out by irradiating the signal recording layer 2 with a light flux through the disk substrate 1 from the signal recording surface 1a, which is one of the principal surfaces of the signal recording surface 1a.

At the center of the disk substrate 1, there is a chucked portion 5 consisting of a center hole 3, which is a transparent hole, and a disk hub 4, which is a plate, for the disk player device to hold the disk substrate 1. is provided. The center hole 3 is a circular through hole penetrating from one main surface to the other main surface of the disk substrate 1, and is formed substantially concentrically and spirally on the signal recording layer 2. It is formed so that its center coincides with the center of curvature of the recording track to be formed. The disc hub 4 is made of a material such as a metal plate, and the center hole 1 is made of a material such as a metal plate.
It is formed into a disk shape with a slightly larger diameter than a. The disc hub 4 is substantially concentric with the center hole 1a so as to close the center hole 1a,
It is arranged on the other main surface of the disk substrate 1.

A hub mounting recess 6 is provided on the other main surface of the disk substrate 1 so as to surround the center hole 3. This hub attachment recess 6 is formed to have a diameter corresponding to the diameter of the disk hub 4 and a depth corresponding to the thickness of the disk hub 4. The disk hub 4 is disposed so as to be fitted into the hub attachment recess 6. Therefore, in this disk hub 4, the upper main surface, that is, the main surface on the side opposite to the side that contacts the disk substrate 1, is flush with the other main surface of the disk substrate 1. .

[0015] On the other main surface of the disk substrate 1, an ultraviolet curable resin film is formed so as to cover the upper main surface of the disk hub 4 and the periphery of the hub mounting recess 6. 7 is formed. This ultraviolet curing resin film 7 is fixed to at least the disk substrate 1, and the disk hub 4 is fixed to the disk substrate 1.
holding on top. That is, the ultraviolet curing resin film 7
Even if they are not fixed to the disk hub 4, they work together with the disk substrate 1 to sandwich the disk hub 4, so that the disk hub 4 can be held on the disk substrate 1. This ultraviolet curing resin film 7 has a thickness of 50 μm.
It is formed to have a predetermined thickness of about m to 100 μm.

The ultraviolet curable resin film 7 can be formed by a so-called spray method, a roll coater method, or a spinning method. The spray method is a method in which an uncured ultraviolet curable resin is sprayed onto the upper main surface of the disk hub 4 and the other main surface of the disk substrate 1, and then the sprayed ultraviolet curable resin is cured by ultraviolet irradiation. . In the roll coater method, an uncured ultraviolet curable resin is applied onto the upper main surface of the disk hub 4 and the other main surface of the disk substrate 1 using a roller, and then the applied ultraviolet curable resin is cured by ultraviolet irradiation. It's a method. In the spinning method, an uncured ultraviolet curable resin is dropped onto the upper main surface of the disk hub 4, and the dropped ultraviolet curable resin is applied to the disk substrate 1 by centrifugal force caused by high-speed rotation of the disk hub 4 and the disk substrate 1. This is a method in which the ultraviolet curable resin is made to flow onto the other main surface of the resin and then cured by ultraviolet irradiation.

It should be noted that on the other main surface of the disk substrate 1, a signal layer is provided to protect the signal recording layer 2, corresponding to the signal recording area of the signal recording surface 1a indicated by arrow A in FIG. A recording layer protective film 8 is formed. The signal recording layer protective film 8 is formed using the same material and method as the ultraviolet curing resin film 7 so as to cover the signal recording layer 2. This signal recording layer protective film 8 is formed to have a predetermined thickness of about 40 μm.

Further, on one main surface of the disk substrate 1, an annular protrusion 9 is provided around the center hole 3. This protrusion 9 is for facilitating a centering operation which will be described later.

In the recording disk according to the present invention configured as described above, the ultraviolet curing resin film 7 has flexibility, so that the disk hub 4 and the disk may be damaged due to changes in environmental temperature or the like. Even if the substrate 1 undergoes thermal expansion or contraction different from that of the substrate 1, no distortion occurs in the disk substrate 1 due to the displacement of the ultraviolet curing resin film 7.

When in use, this recording disk is placed on a disk table 201 attached to a drive shaft 202a of a spindle motor 202 of a disk player, as shown in FIG. The disc play device is a device that writes and/or reads information signals to and from this recording disc. The disk table 201 is formed into a disk shape with a larger diameter than the center hole 3, and is supported by the drive shaft 202a. The center hole 3 on one main surface of the disk substrate 1 is provided on the upper surface of the disk table 201.
The surrounding portion, that is, the tip of the protrusion 9 is placed.

[0021] A centering protrusion 203 is provided on the disc table 201 in a protruding manner. This centering protrusion 203 is located on the disc table 2.
The distal end side supported by the disk substrate 1 is smaller in diameter than the proximal end side, and is formed into a substantially truncated conical shape, and has an outer diameter that can be fitted into the center hole 3 of the disk substrate 1. This centering protrusion 203 is provided on the disk table 201 with its center aligned with the axis of the drive shaft 202a of the spindle motor 202. Further, a magnet (not shown) for attracting the disk hub 4 is built into the centering protrusion 203.

When the disk substrate 1 is placed on the disk table 201, the centering protrusion 2
03 attracts the disc hub 4, so that the centering protrusion 203 brings the outer peripheral surface into contact with the inner peripheral edge of the center hole 3. This centering protrusion 203 is formed by bringing the outer circumferential surface into contact with the inner circumferential edge of the center hole 3 in this way.
Center the center hole 3 with this centering protrusion 2
A so-called centering operation is performed to match the center of 03. In this way, the disk substrate 1 is positioned at a predetermined position relative to the disk table 201 by the upper surface of the disk table 201 and the centering protrusion 203.

[0023] Since the protrusion 9 is provided around the center hole 3, the center hole 3 viewed from one main surface side of the disk substrate 1
is made as deep as the height of the protrusion 9. Therefore, in this recording disk, the height of the centering protrusion 203 can be made higher than in the case where the protrusion 9 is not provided, and the centering operation is facilitated.

In the recording disk according to the present invention mounted in the disk player apparatus as described above, the disk substrate 1 is rotated by the disk table 201 as the disk table 201 is rotated by the spindle motor 202. Rotation operation is performed with

In the disc player device, an optical pickup device (not shown) writes and/or reads information signals to and from the signal recording layer 2. This optical pickup device has the above-mentioned signal recording surface 1a.
The signal recording surface 1a is moved over the inner and outer peripheries of the signal recording surface 1a in correspondence with at least the signal recording area. This optical pickup device includes an objective lens,
A light beam is irradiated onto the signal recording layer 2 through the disk substrate 1 through this objective lens, and the signal recording layer 2 is
Writes and/or reads information signals to and from.

In the recording disk according to the present invention, the ultraviolet curable resin film 7 is formed over the entire surface of the other main surface of the disk substrate 1, so that the outer peripheral side of the ultraviolet curable resin film 7 is It may also be used as a signal recording layer protective film. In addition, the ultraviolet curing resin film 7
When forming by the spinning method, as shown in FIG. 4, in order to prevent the uncured ultraviolet curable resin from flowing onto the signal recording layer 2, it is necessary to A prevention protrusion 10 may also be provided. This outflow prevention protrusion 10 is integrally formed with the disk substrate 1.

The film body of the recording disk according to the present invention is not limited to the one made of ultraviolet curing resin as shown in the above embodiments, but can be made of various synthetic resin materials. can.

Furthermore, the recording disk according to the present invention is not limited to being constructed as a so-called magneto-optical disk as shown in the above embodiments, but may be constructed as a so-called optical disk.

Further, the recording disk according to the present invention is rotatably housed in a thin housing-like cartridge having a rectangular main surface portion whose length on one side is slightly longer than the diameter of the disk substrate 1, and the recording disk is rotatably housed in a cartridge. It may also be used as a recording disk constituting a.

[0030]

As described above, in the recording disk according to the present invention, the plate formed of a material different from that of the disk substrate and placed on one main surface of the disk substrate can It is held on the disk substrate by a film formed over the main surface on the side opposite to the side that contacts the substrate and on the main surface on which the plate of the disk substrate is placed.

[0031] The above-mentioned membrane body has flexibility if it is formed thinly from a synthetic resin material or the like. Therefore, in this recording disk, even if the plate body and the disk substrate undergo different thermal expansion or contraction due to changes in environmental temperature, etc., the film body will not be displaced and the disk substrate will not be distorted. You can do it like this.

That is, the present invention provides a recording disk in which a plate made of a material different from the disk substrate is securely attached to the disk substrate, and distortion of the disk substrate due to changes in environmental temperature or the like is prevented. It is something that can be done.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view showing the configuration of a recording disk according to the present invention and a state in which the recording disk is installed in a disk player device.

FIG. 2 is an enlarged vertical cross-sectional view of a main part showing the configuration of the recording disk.

FIG. 3 is a plan view showing the configuration of the recording disk.

FIG. 4 is an enlarged vertical cross-sectional view of a main part showing another example of the configuration of the disk cartridge.

FIG. 5 is a longitudinal cross-sectional view showing the configuration of a conventional recording disk.

[Explanation of symbols]

1......Disk board 1a...
・・・・・・Signal recording surface

Claims (1)

[Claims] 1. A disk substrate having at least one main surface serving as a signal recording surface and having a through hole in the center;
A plate body formed of a material different from the disk substrate and placed on one main surface of the disk substrate with the through hole closed; and a plate body facing the side of the plate body that contacts the disk substrate. A recording disk comprising: a film body formed over a main surface portion of the side and a main surface portion of the disk substrate on which the plate body is placed, and holding the plate body on the disk substrate.