JPH06131702A - optical disk - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide an optical disc having improved mechanical reliability during high-speed rotation by alleviating the concentrated stress in the portion where the stress is concentrated during high-speed rotation of the optical disc. [Structure] The present optical disk 10A includes a substrate 13 having a recording layer 11 formed inside and a central hole 12 formed in the central portion, and a pair of clamps attached to the central portion from both sides of the substrate 13, respectively. With hubs 14, 14 of
Ring members 15, 15 each having an outer diameter gradually increasing from the upper end of the outer periphery toward the surface of the substrate 13 are inserted into and attached to the outer peripheral surfaces of the hubs 14, 14, respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk capable of recording and erasing information on a recording film or reproducing information recorded on the recording film by using a minute light spot.

[0002]

2. Description of the Related Art As conventional optical disks of this type, those shown in FIGS. 7 to 10 are known. Figure 7-
FIG. 9 shows an optical disk of the type in which a hub is attached to a substrate, and FIG. 10 shows an optical disk of the type without a hub. Therefore, a conventional optical disc will be described with reference to FIGS.

FIG. 7 and FIG. 8 show a type of optical disc with a hub, in which the hub is adhered from both sides of the substrate. This type of optical disc 10 is generally 5.25
The optical disc 10 is adopted as an inch size optical disc. As shown in FIG. 1, the optical disc 10 includes a substrate 13 having a recording layer 11 and a central hole 12 sandwiched therein,
The substrate 13 is provided with a pair of clamping hubs 14 and 14 attached to both surfaces of the substrate 13, respectively. The substrate 13 has a recording film 11A on one side,
The structure substrates 13A and 13B on which 11B is formed are bonded together to form a sandwich structure in which the recording films 11A and 11B are integrated as the recording layer 11 inside the substrate 13. A magnetic plate 14A is embedded in the center of the hub 14. The optical disk 10 is configured to record and reproduce information while rotating by the rotation of the spindle 20. As shown in FIG. 7, the spindle 20 includes a substantially bowl-shaped flange portion 21 for supporting the substrate 10 around the hub 14 thereof,
A penetrating shaft portion 22 formed at the center of the flange portion 21 and penetrating the central hole 14B of the hub 14 and a magnet 23 attached to the upper surface of the flange portion 21 so as to surround the penetrating shaft portion 22 are provided. It is configured to have.

Next, the operation will be described. When the optical disc 10 is used as shown in FIG. 7, the optical disc 10 is mounted on the flange portion 21 by aligning the central hole 14B of the hub 14 with the through shaft portion 22 of the spindle 20. At 14A, it is attracted to the magnet 23 and clamped to the spindle 20. Then
When the spindle 20 is driven, the optical disk 10 becomes 1800
Rotate at high speed at ~ 2400 rpm. Along with this rotation, information is recorded on the recording layer 11 of the optical disc 10 via an optical head (not shown) of the optical disc drive, and the information recorded on the recording layer 11 is reproduced or erased. Then, from now on, the rotational speed of the optical disk 10 is 3000 to 5000 rp for the purpose of further speeding up data transfer.
The optical discs 30 and 40 to be described later are increasing in speed to m.
Similarly, high speed rotation is achieved.

In addition, FIG. 9 shows an optical disk with a hub.
It shows a type in which the hub is attached from one side of the substrate. This type of optical disc 30 is generally adopted as a 3.5-inch size optical disc, and this optical disc 30 includes a substrate 33 having a recording film 31 and a central hole 32 formed on one side, as shown in FIG. The substrate 33 is provided with a metal hub 34 for clamping which is inserted into the central hole 32 from the recording film 31 side. Further, in such an optical disc 30, in addition to the metal hub 34,
A composite type hub is used in which only the portion of the spindle 20 that is attracted to the magnet 23 is made of metal. When this optical disk 30 is used, the optical disk 30 is mounted in the center hole 3 of the metal hub 34 in the manner described above.
When mounted on the spindle 20 with 4B as a reference, the metal hub 34 attracts the magnet 23 of the spindle 20 to clamp the optical disk 30 on the spindle 20, and the information is recorded, reproduced, and erased. At this time, the substrate 3
3, the area supported by the flange portion 21 of the spindle 20 is used as the clamp area 35, and the outside of the clamp area 35 with a gap is used as the data area 36.

Further, FIG. 10 shows an optical disk of a type having no hub. This type of optical disc 40 is generally adopted as an optical disc of 5.25 inch size, and as shown in the figure, this optical disc 40 has a substrate 43 having a recording layer 41 and a central hole 42 sandwiched therein. And a magnetic plate 44 for clamping which is disposed inside the recording layer 41 inside the substrate 43 with a gap therebetween. Then, the substrate 43 is configured by laminating the constituent substrates 43A and 43B having the recording films 41A and 41B formed on one surface thereof. When this optical disk 30 is used, it can be used in the same manner as the optical disks 10 and 30 with the hub described above. Also at this time, the substrate 43 is connected to the spindle 20.
The area supported by the flange portion 21 of the clamp area 45 is
The outer side of the clamp area 45 separated by a gap is used as a data area 46.

[0007]

However, in the case of the conventional optical disk 10, the spindle 20 has 1800
When the optical disc 10 clamped by the spindle 20 is rotated at a high speed of ˜2400 rpm, the outer peripheral edge portion of the substrate 13 vibrates up and down violently due to the high-speed rotation, which causes a large tensile stress at the boundary between the substrate 13 and the hub 14. Will be added repeatedly. Since the substrate 13 and the hub 14 are significantly different in radial cross-sectional area, the rotation speed of the optical disk 10 will be doubled as the data transfer speed increases in the future. At a high speed of 3000 to 5000 rpm, the tensile stress is concentrated more and more on the boundary, and the reliability of the mechanical strength of the substrate 13 is lowered. In some cases, cracks C, C are formed on the boundary as shown in FIG. There was a problem that it might occur.

Further, in the case of the conventional optical disk 30,
When the optical disc 30 rotates at high speed, the substrate 33
The outer peripheral edge of the spindle violently vibrates up and down, and the flange portion 21 of the spindle 20, particularly the surface portions 37 and 38 of the substrate 33 at the lower ends of the inner and outer peripheral surfaces of the flange portion 21, are repeatedly subjected to concentrated stress, and the mechanical strength of this portion is increased. There is a problem that reliability is lowered by high-speed rotation of the optical disk 30, and in some cases, cracks (not shown) are easily generated in this portion.

Further, in the case of the conventional optical disc 40,
When the optical disc 40 rotates at high speed, the substrate 43
The outer peripheral edge portion of the spindle violently vibrates up and down, and repeatedly receives concentrated stress on the flange portion 21 of the spindle 20, especially on the surface portions 47 and 48 of the substrate 33 at the lower ends of both the inner and outer peripheral surfaces of the flange portion 21, and the mechanical strength of this portion There is a problem that reliability is lowered due to high-speed rotation of the optical disc 40, and in some cases, cracks (not shown) easily occur in this portion.

The present invention has been made in order to solve the above-mentioned problems, and alleviates the concentrated stress in a portion where stress is concentrated at the time of high speed rotation of an optical disk, and enhances the mechanical strength of that portion, thereby allowing high speed rotation. The purpose is to provide an optical disc with improved mechanical reliability.

[0011]

An optical disk according to claim 1 of the present invention is a substrate having a recording layer formed inside and a central hole formed in the central portion, and a central portion on both sides of the substrate. A pair of clamp hubs are attached to each other, and a ring member whose outer diameter is gradually increased from the upper end of each outer periphery toward the surface of the substrate is attached to the outer periphery of each hub.

The optical disk according to a second aspect of the present invention is a substrate having a recording layer formed inside and a central hole formed in the central portion, and a substrate having both central portions formed on both sides thereof. And a reinforcing ring having a width extending from the inner side to the outer side of the outer circumference of the hub is positioned inside the recording layer in the radial direction and is provided inside the substrate. .

An optical disk according to a third aspect of the present invention is a substrate having a recording film and a central hole formed on one surface, and a clamping hub fitted in the central hole from the recording film side of the substrate. And the outer peripheral surface of the clamp area is formed in a tapered shape, while the thickness of the clamp area of the substrate is formed to be thicker than the thickness of the data recording area outside thereof.

The optical disk according to a fourth aspect of the present invention is a substrate having a recording film and a central hole formed on one surface, and a clamping hub fitted into the central hole from the recording film side of the substrate. And a support ring having a width extending from the outer peripheral end of the hub to the outside of the clamp region of the substrate is attached to the recording film.

The optical disk according to a fifth aspect of the present invention is a substrate having a recording layer formed inside and a central hole formed in the central portion, and a gap is formed inside the substrate inside the recording layer. And a magnetic plate for clamping which is interposed so as to be spaced apart from each other, and the thickness of the clamp region of the substrate is formed to be thicker than the thickness of the data recording region outside thereof, and the outer peripheral surface of the clamp region is tapered. It is a thing.

An optical disk according to a sixth aspect of the present invention is a substrate having a recording layer formed inside and a central hole formed in the central portion, and a gap inside the substrate inside the recording layer. And a magnetic plate for clamping which is interposed apart from each other, and the outer end of the magnetic plate extends outside the outer periphery of the clamp region of the substrate.

[0017]

According to the first aspect of the present invention, since the outer peripheral surface of the hub has its radial cross-sectional area gradually reduced through the ring member, the optical disk rotates at a high speed and the outer peripheral edge of the substrate. Even if the portion vibrates up and down violently, the concentrated stress on the substrate surface can be relieved by the ring member.

According to the second aspect of the present invention, since the reinforcing ring is provided inside the portion of the surface of the substrate to which the concentrated stress is applied, the optical disk rotates at a high speed and the outer peripheral edge of the substrate. Even if the portion vibrates up and down violently, the reinforcing ring can suppress the displacement of the substrate on the outer periphery of the hub and reduce the load due to the concentrated stress.

According to the third aspect of the present invention, the thickness of the clamp area of the substrate is formed to be thicker than the thickness of the data recording area outside the clamp area, and the outer peripheral surface of the clamp area is tapered. Since the optical disc is rotated at a high speed and the outer peripheral edge of the substrate vibrates up and down violently, mechanical strength is secured in the thick clamp region and stress concentration is relieved in the tapered portion on the outer periphery of the clamp region. be able to.

According to the fourth aspect of the present invention, since the support ring having the width extending from the outer peripheral edge of the hub to the outside of the clamp area of the substrate is attached to the recording film side, the optical disk rotates at a high speed. Even if the outer peripheral edge of the substrate vibrates up and down violently, the support ring can suppress the displacement of the substrate on the outer circumference of the hub and reduce the load due to the concentrated stress.

According to the fifth aspect of the present invention, the thickness of the clamp area of the substrate is made thicker than the thickness of the data recording area outside thereof, and the outer peripheral surface of the clamp area is tapered. Since the optical disc is rotated at a high speed and the outer peripheral edge of the substrate vibrates up and down violently, mechanical strength is secured in the thick clamp region and stress concentration is relieved in the tapered portion on the outer periphery of the clamp region. be able to.

According to the sixth aspect of the present invention, since the outer edge of the magnetic plate extends outside the outer periphery of the clamp region of the substrate, the magnetic plate displaces the substrate at the outer periphery of the clamp region. Can be suppressed and the load due to the concentrated stress can be reduced.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Based on the embodiments shown in FIGS. 1 to 6, the same or corresponding parts as in the prior art will be designated by the same reference numerals, and the description will focus on the characteristics of the present invention. In each of the drawings, FIG. 1 is a sectional view showing a main part of an embodiment of a hub-adhesion type optical disk of the present invention, and FIG. 2 is a main part of another embodiment of a hub-adhesion type optical disk of the present invention. 4 is a sectional view showing a main part of an embodiment of a hub insertion type optical disk of the present invention, FIG.
FIG. 6 is a sectional view showing a main part of another embodiment of the hub insertion type optical disk of the present invention, FIG. 5 is a sectional view showing a main part of an embodiment of the hubless type optical disk of the present invention, and FIG. FIG. 9 is a cross-sectional view showing the main parts of another embodiment of the hubless type optical disc of the invention.

Example 1. Optical disc 10A of the present embodiment
As shown in FIG. 1, a substrate 13 having a recording layer 11 formed inside and a central hole 12 formed in the central portion,
The substrate 13 includes a pair of clamping hubs 14 and 14 attached to the central portions of both sides of the substrate 13, respectively.
4, 14 on the outer peripheral surface from the upper end of each outer periphery
3 Ring members 15, 1 whose outer diameter gradually increases toward the surface
5 are inserted and configured.

That is, the radial cross section of the ring member 15 has a tapered outer peripheral surface and a cylindrical inner peripheral surface perpendicular to the substrate 13. Further, by forming the tapered surface 15A on the outer peripheral surface of the ring member 15 as described above, the hub 14 integrated with the ring member 15 is formed such that the radial cross-sectional area from the upper end of the outer peripheral surface to the substrate 13 is gradually reduced. As a result, even if the optical disk 10A rotates at high speed and the outer peripheral edge of the substrate 13 vibrates up and down violently, the taper surface 15A of the ring member 15 can alleviate the concentrated stress on the surface of the substrate 13. ing. Others are configured according to the conventional optical disc 10. The substrate 13 is made of polycarbonate resin in the same size as the conventional one and has an ISO standard size of 5.25 inches, and the ring member 15 is also made of polycarbonate resin like the substrate 13.

Then, the optical disk 10A was manufactured as follows. The ring member 15 was made of a polycarbonate resin, and the conventional optical disk 10 of ISO standard 5.25 inches including the polycarbonate substrate 13 was prepared. Then, the two ring members 15 are fitted into the hubs 14 of the conventional optical disk 10 and fixed on both surfaces of the substrate 13 with an adhesive to manufacture the optical disk 10A.
I prepared one. In addition, the conventional I without the ring member 15
Three SO standard 5.25 inch optical disks 10 were prepared.

Next, the three optical disks 10 were artificially accelerated and deteriorated in a thermostat at a temperature of 80 ° C. and a relative humidity of 80% at high temperature and high humidity. Then, the optical disks 10 were taken out at regular intervals, and each was rotated at a high speed of 5000 rpm by the spindle 20 to observe the surface of the substrate 13 on the outer peripheral portion of each hub 14. Further, the three optical disks 10A of this example were also subjected to accelerated deterioration and rotation under the same conditions as the conventional ones, and then the respective optical disks 10A were observed. As a result of the above observation, in the case of the conventional optical disc 10, although the cracks C and C were generated at the boundary of the hub 14 as shown in FIG. No cracks were observed.

Consider the results. When the conventional optical disc 10 is clamped by the spindle 20,
The magnet 14A of the hub 14 is attracted by the magnetic plate 23 of the spindle 20, the substrate 13 contacts the flange portion 21 and the substrate 13 is pushed up, and tensile stress is generated on the surface of the substrate 13 at the outer peripheral end of the hub 14. . When the optical disk 10 is further rotated at a high speed, the outer peripheral edge portion of the substrate 13 warps upward, and tensile stress is repeatedly applied to the surface of the substrate 13 at the outer peripheral end of the hub 14. Then, when the optical disk 10 rotates, the tensile stress concentrates on the surface of the substrate 13 to generate minute cracks C, C. However, in the case of the optical disc 10A of the present embodiment, the outer peripheral surface of the hub 14 is gradually reduced in cross-sectional area in the radial direction through the ring member 15, so that the optical disc 10A rotates at a high speed and the outer peripheral edge of the substrate 13 is increased. It was found that the tapered surface 15A of the ring member 15 alleviates the concentrated stress on the surface of the substrate 13 at the outer peripheral edge thereof to suppress the generation of minute cracks and improve the durability even if the portion vibrates up and down violently. .

As described above, according to the present embodiment, the outer peripheral surface of the hub 14 has its radial cross-sectional area gradually reduced through the tapered portion of the ring member 15.
It is possible to relieve the concentrated stress in the portion where the stress concentrates at the time of high-speed rotation of A, and improve the mechanical reliability during the high-speed rotation.

In the present embodiment, the ring member 15 has been described as a member separate from the hub 14, but the two members 14 and 15 may be integrally molded. Further, the ring member 15 having the tapered outer peripheral surface has been described.
The outer peripheral surface of the hub 14 may have an R-shape in which the outer diameter gradually increases from the upper end of the outer periphery of the hub 14 toward the surface of the substrate 13.

Example 2. Optical disc 10B of the present embodiment
2, the reinforcing ring 16 having a width ranging from the inner side to the outer side of the outer circumference of the hub 14 is positioned on the inner side in the radial direction of the recording layer 11 interposed in the substrate 13, and the substrate 13 is
It is provided inside. That is, in the case of the optical disc 10B of the present embodiment, the recording layer 11 interposed in the substrate 13 is formed in the region from the outer peripheral edge of the substrate 13 to the outer side of the outer peripheral surfaces of the hubs 14 and 14, Reinforcing ring 16
Is sandwiched between the constituent substrates 13A and 13B on the inner side in the radial direction of the recording layer 11 as in the recording layer 11. As described above, in the optical disc 10B of the present embodiment, the reinforcing ring 16 is interposed inside the portion of the surface of the substrate 13 to which the concentrated stress is applied, so that the optical disc 10B rotates at a high speed.
Even when the outer peripheral edge portion of 3 vibrates up and down violently, the reinforcing ring 16 suppresses the displacement of the substrate 13 on the outer periphery of the hub 14 and reduces the load of concentrated stress in this portion. . The others are configured according to the conventional optical disc 10.

The optical disk 10B is manufactured as follows. First, an ISO standard 5.25-inch configuration substrate 13A having a recording film 11A formed on one surface.
A substrate 13B for construction having a recording film 11B formed on one side similar to this, and a hub 14 having an outer diameter of 25 mm.
And a reinforcing ring 16 made of magnetic stainless steel having an inner diameter of 17 mm and an outer diameter of 33 mm. After that, as shown in FIG. 2, the reinforcing ring 16 is center-aligned and sandwiched between the constituent substrates 11A and 11B, and the both 11A and 11B are bonded together.
Is fixed to the surface of the substrate 13 with an adhesive and the optical disc 1
OB was prepared.

Next, the same accelerated deterioration test and high-speed rotation test as in Example 1 were performed on the optical disk 10B and the conventional optical disk 10, and Example 1 was performed for each.
The same observations as above were made. As a result, in the case of the conventional optical disk 10, although the cracks C and C were generated at the boundary of the hub 14 as shown in FIG. 8, the cracks were generated in the case of the optical disk 10A of the present embodiment. I was not able to admit.

Therefore, in the case of the optical disk 10B of the present embodiment, the reinforcing ring 16 is interposed inside the portion of the surface of the substrate 13 to which the concentrated stress is applied, so that the optical disk 10B.
Even when B rotates at a high speed and the outer peripheral edge of the substrate 13 vibrates violently up and down, the reinforcing ring 16 suppresses the displacement of the substrate 13 on the outer periphery of the hub 14 to reduce the load due to the concentrated stress and to prevent the generation of microcracks. It was found that the suppression was suppressed and the durability was improved.

As described above, according to this embodiment, since the reinforcing ring 16 is provided inside the portion of the surface of the substrate 13 to which the concentrated stress is applied, the stress is concentrated on the portion where the stress is concentrated when the optical disk 10B is rotated at a high speed. It is possible to enhance the mechanical strength of the, and thus enhance the mechanical reliability during high-speed rotation.

In this embodiment, the reinforcing ring 16 is made of non-magnetic stainless steel.
The reinforcing ring 16 is not particularly limited as long as it is a non-magnetic material having high mechanical strength. Further, by simultaneously embedding the reinforcing ring 16, the manufacturing process of the optical disc 10B can be simplified.

Example 3. Optical disc 30A of the present embodiment
As shown in FIG. 3, a substrate 33 having a recording film 31 and a central hole 32 formed on one surface, and a metal hub 34 for clamping fitted to the central hole 32 from the recording film 31 side of the substrate 33. And a taper surface 33A is formed on the outer peripheral surface of the clamp area 35 while the wall thickness of the clamp area 35 of the substrate 33 is made thicker than the thickness of the data recording area 36 outside thereof. There is. As described above, in the optical disc 30A of the present embodiment, the thickness of the clamp area 35 is made thicker than the thickness of the data recording area 36 on the outer side thereof, and the taper surface 33 is formed on the outer peripheral surface of the clamp area 35.
By forming A, the mechanical strength is ensured in the thick clamp area 35 and the taper of the outer circumference of the clamp area 35 is achieved even when the optical disk 30A rotates at a high speed and the outer peripheral edge of the substrate 33 vibrates up and down violently. The surface 33A is configured so that stress concentration can be relieved. The others are configured according to the conventional optical disc 30.

Then, three optical disks 30A were manufactured as follows. First, the clamp area 35 is 1.
5 mm, data area 36 is 1.2 mm and tapered surface 33A
An ISO standard 3.5-inch substrate 33 having an inclination of 45 ° is produced, and then a metal hub 34 is inserted into the central hole 32 of the substrate 33 by using an adhesive agent, and the optical disc 30A of the present embodiment. Was produced.

Next, the above-mentioned optical disk 30A and the conventional optical disk 30 were subjected to the same accelerated deterioration test and high-speed rotation test as those of the above-mentioned respective examples, and the same observations as those of the above-mentioned respective examples were carried out. As a result, in the case of the conventional optical disk 30, the flange portion 21 of the spindle 20, especially the substrate 33 at the lower ends of both the inner and outer peripheral surfaces of the flange portion 21.
Although the surface portions 37 and 38 (see FIG. 9) of the optical disk 30 are repeatedly subjected to concentrated stress and microcracks (not shown) are generated in these portions, in the case of the optical disk 30A of the present embodiment, the cracks are generated. Was not observed.

Therefore, in the case of the optical disc 30A of the present embodiment, the thickness of the clamp area 35 of the substrate 33 is formed thicker than the thickness of the data recording area 36 outside thereof.
Moreover, the outer peripheral surface of the clamp region 35 is tapered surface 33A.
Therefore, the optical disc 30A rotates at high speed and the substrate 33
Even if the outer peripheral edge portion of the clamp region vibrates up and down violently, mechanical strength is secured in the thick clamping region 35, and stress concentration is relaxed by the tapered surface 33C on the outer periphery of the clamping region 35 to suppress generation of microcracks. Have been found to improve durability.

As described above, according to the present embodiment, the thickness of the clamp area 35 of the substrate 33 is made thicker than the thickness of the data recording area 36 outside thereof, and the outer peripheral surface of the clamp area 35 is tapered. With this configuration, it is possible to relieve the concentrated stress in a portion where stress is concentrated during high-speed rotation of the optical disc 30A, and increase the mechanical strength of that portion, thereby improving the mechanical reliability during high-speed rotation.

Although the metal hub 34 is used in this embodiment, the hub may be a composite type made of metal and plastic.

Example 4. Optical disc 30B of the present embodiment
As shown in FIG. 4, a substrate 33 having a recording film 31 and a central hole 32 formed on one surface, and a metal hub 34 for clamping fitted to the central hole 32 from the recording film 31 side of the substrate 33. And a metal support ring 39 having a width extending from the outer peripheral end of the metal hub 34 to the outside of the clamp region 35 of the substrate 33 is attached to the recording film 31. Thus, the optical disk 30 of this embodiment
B is a metal support ring 39 having a width extending from the outer peripheral edge of the metal hub 34 to the outside of the clamp region 35 of the substrate 33.
By depositing on the central portion of the recording film 31, the metal support ring 39 ensures the mechanical strength of the substrate 33 even if the optical disc 30B rotates at a high speed and the outer peripheral edge portion of the substrate 33 vibrates vertically. It is configured. The others are configured according to the conventional optical disc 30.

Then, three optical disks 30B were manufactured as follows. First, a substrate 33 made of polycarbonate resin having an ISO standard of 3.5 inches and a thickness of 1.2 mm.
While the outer diameter is the flange portion 2 of the spindle 20
A metal support ring 39 having a diameter of 8 mm larger than the outer diameter of 1 and a thickness of 0.4 mm was produced. After that, the metal support ring 39 was fixed to the recording film 31 side by using an adhesive with the axial center aligned with the central hole 32 of the substrate 33. Next, an adhesive was used to insert a metal hub 34 into the central hole 32 of the substrate 33 to manufacture an optical disk 30B of this embodiment.

Next, the above-mentioned optical disk 30B and conventional optical disk 30 were subjected to the same accelerated deterioration test and high-speed rotation test as those of the above-mentioned respective embodiments, and the same observations as those of the above-mentioned respective embodiments were carried out. As a result, in the case of the conventional optical disk 30, the flange portion 21 of the spindle 20, especially the substrate 33 at the lower ends of both the inner and outer peripheral surfaces of the flange portion 21.
In the case of the optical disk 30B of the present embodiment, although the surface stresses 37, 38 (see FIG. 9) of FIG. Was not observed.

Therefore, in the case of the optical disk 30B of the present embodiment, the metal support ring 39 having a width extending from the outer peripheral end of the metal hub 34 to the outside of the clamp area 35 of the substrate 33 is adhered to the recording film 31. Optical disk 30B
Even if the outer peripheral edge portion of the substrate 33 vibrates violently up and down due to high speed rotation, the metal support ring 39 suppresses the displacement of the substrate 33 on the outer periphery of the metal hub 34, reduces the load due to concentrated stress, and improves durability. I knew that.

As described above, according to the present embodiment, the metal support ring 39 having a width extending from the outer peripheral end of the metal hub 34 to the outside of the clamp area 35 of the substrate 33 is attached to the recording film 31 side, so that the optical disc. It is possible to enhance the mechanical strength of the portion of 30B where stress is concentrated during high-speed rotation, and thus enhance the mechanical reliability during high-speed rotation.

In the present embodiment, the metal hub 34 is used, but the hub may be a composite type made of metal and plastic. The metal support ring 39 may be made of a non-magnetic material or a magnetic material in consideration of the clamping force of the spindle 20.

Example 5. Optical disc 40A of the present embodiment
Is a substrate 43 having a recording layer 41 formed inside and a central hole 42 formed in the central portion, as shown in FIG.
A magnetic plate 44 for clamping is provided inside the substrate 43 with a gap inside the recording layer 41, and the thickness of the clamp region 45 of the substrate 43 is set to the data recording region 46 outside thereof.
Thicker than that of the clamp region 4 and
5, the outer peripheral surface of 5 is formed with a tapered surface 49.
As described above, in the optical disc 40A of the present embodiment, the thickness of the clamp area 45 of the substrate 43 is set to the data recording area 46 outside the clamp area 45.
Thicker than that of the clamp region 4 and
By forming the taper surface 49 on the outer peripheral surface of 5, the optical disc 40A rotates at a high speed and the outer peripheral edge portion of the substrate 43 vibrates up and down violently. The taper surface 49 on the outer periphery of the clamp region 45 is configured to reduce stress concentration.
The others are configured according to the conventional optical disc 40.

Then, three optical discs 40A were manufactured as follows. First, the clamp area 45 is 1.
4 mm, the data area 46 is 1.2 mm, and the outer peripheral surface is 4 mm.
Two ISO standard 5.25-inch substrates 43 having a 5 ° tapered surface 49 are produced, and then two substrates 43A,
An optical disk 40A without a hub was manufactured by sandwiching the magnetic plate 44 with the recording films 41A and 41B inside with the magnetic film 43B interposed therebetween. In addition, the conventional ISO standard 5.25 inch optical disk 40
Prepared 3 sheets.

Next, the above-mentioned optical disc 40A and conventional optical disc 40 were subjected to the same accelerated deterioration test and high-speed rotation test as in the above-mentioned respective examples, and the same observations as in the above-mentioned respective examples were carried out. As a result, in the case of the conventional optical disc 40, the flange portion 21 of the spindle 20, especially the substrate 43 at the lower end of both the inner and outer peripheral surfaces of the flange portion 21.
Although the surface portions 47 and 48 (see FIG. 10) of the disk have been repeatedly subjected to concentrated stress and microcracks (not shown) have been generated in these portions, the optical disk 40A of the present embodiment.
In the case of No, no crack was observed.

Therefore, in the case of the optical disc 40A of the present embodiment, the thickness of the clamp area 45 of the substrate 43 is formed thicker than the thickness of the data recording area 46 outside thereof.
Moreover, since the outer peripheral surface of the clamp region 45 is tapered, the optical disc 40A rotates at a high speed and the substrate 43 is rotated.
Even if the outer peripheral edge of the clamp region vibrates up and down violently, mechanical strength is secured in the thick clamp region 45, and stress concentration is relaxed by the tapered surface 49 on the outer periphery of the clamp region 45 to suppress the generation of microcracks. Have been found to improve durability.

As described above, according to the present embodiment, the thickness of the clamp area 45 of the substrate 43 is made thicker than the thickness of the data recording area 46 outside thereof, and the outer peripheral surface of the clamp area 45 is formed. Since the taper shape is used, it is possible to relieve the concentrated stress in a portion where the stress is concentrated during high-speed rotation of the optical disc 40A, and to increase the mechanical strength of the portion, thereby improving the mechanical reliability during high-speed rotation.

Example 6. Optical disc 40B of the present embodiment
As shown in FIG. 6, a substrate 43 having a recording layer 41 and a central hole 42 sandwiched therein, and a clamp interposed inside the substrate 43 on the central hole 42 side apart from the recording layer 41. And a magnetic plate 44 for use with the magnetic plate 44, and the outer end of the magnetic plate 44 extends outside the outer periphery of the clamp region 45 of the substrate 43. As described above, in the optical disc 40B of this embodiment, the outer end of the magnetic plate 44 is extended outside the outer periphery of the clamp region 45 of the substrate 43, and the magnetic plate 44 suppresses the displacement of the substrate 43 on the outer periphery of the clamp region 45. It is configured to reduce the load due to concentrated stress. The others are configured according to the conventional optical disc 40.

Then, three optical disks 40B were manufactured as follows. First, a substrate 4 made of polycarbonate resin having an ISO standard of 5.25 inches and a thickness of 1.2 mm.
3 are prepared, and then the two substrates 43A and 43B are placed with the respective recording films 41A and 41B inside, and the magnetic plate 44 having an outer diameter larger than the clamp region 45 by about 4 mm is provided between the two substrates 43A and 43B. The optical disc 40B without a hub was produced by sandwiching and pasting the recording films 41A and 41B together. In addition, the conventional ISO standard 5.25
Three 3 inch inch optical disks 40 were prepared.

Next, the above-mentioned optical disc 40B and conventional optical disc 40 were subjected to the same accelerated deterioration test and high-speed rotation test as in the above-mentioned respective examples, and the same observations as in the above-mentioned respective examples were carried out. As a result, in the case of the conventional optical disc 40, the flange portion 21 of the spindle 20, especially the substrate 43 at the lower end of both the inner and outer peripheral surfaces of the flange portion 21.
Although the surface portions 47 and 48 (see FIG. 10) of the disk are repeatedly subjected to concentrated stress and micro cracks (not shown) are generated in these portions, the optical disk 40B of the present embodiment.
In the case of No, no crack was observed.

Therefore, in the case of the optical disc 40B of the present embodiment, since the outer end of the magnetic plate 44 is extended to the outside of the outer periphery of the clamp region 45 of the substrate 43, the outer periphery of the clamp region 45 is covered by the magnetic plate 44. It has been found that the displacement of the substrate is suppressed, the load due to the concentrated stress is reduced, the generation of microcracks is suppressed, and the durability is improved.

As described above, according to the present embodiment, since the outer end of the magnetic plate 44 is extended outside the outer circumference of the clamp region 45 of the substrate 43, the machine in the portion where stress concentrates when the optical disc 40B rotates at high speed. It is possible to increase the mechanical strength and, therefore, the mechanical reliability during high-speed rotation. Although the wide magnetic plate 44 is used in the above embodiment, if the magnetic plate 44 may adversely affect the data area 36, the inner peripheral portion thereof is made of a magnetic material and the outer peripheral portion thereof is formed. May be a non-magnetic material.

Needless to say, the present invention is not limited to the above embodiments.

[0060]

As described above, according to the first aspect of the present invention, the outer peripheral surface of the hub is gradually reduced in radial cross-sectional area through the ring member. It is possible to provide an optical disc in which the concentrated stress in the portion where the stress is concentrated during rotation is relaxed and the mechanical reliability during high speed rotation is improved.

According to the second aspect of the present invention, since the reinforcing ring is provided inside the portion of the substrate surface to which the concentrated stress is applied, the portion where the stress is concentrated when the optical disc is rotated at a high speed. It is possible to provide an optical disc having an increased mechanical strength and a high mechanical reliability during high-speed rotation.

According to the third aspect of the present invention, the thickness of the clamp area of the substrate is made thicker than the thickness of the data recording area outside thereof, and the outer peripheral surface of the clamp area is tapered. As a result, it is possible to provide an optical disc that relieves the concentrated stress at the portion where the stress is concentrated during high-speed rotation of the optical disc and enhances the mechanical strength of that portion, thus increasing the mechanical reliability during high-speed rotation. .

According to the fourth aspect of the present invention, since the support ring having the width extending from the outer peripheral end of the hub to the outside of the clamp area of the substrate is attached to the recording film,
It is possible to provide an optical disc in which the mechanical strength of a portion where stress is concentrated at the time of high-speed rotation of the optical disc is enhanced, and thus the mechanical reliability at the time of high-speed rotation is enhanced.

According to the fifth aspect of the present invention, the thickness of the clamp area of the substrate is made thicker than the thickness of the data recording area outside the clamp area, and the outer peripheral surface of the clamp area is formed. Since the taper shape is provided, it is possible to provide an optical disc that relieves the concentrated stress in the portion where the stress is concentrated at high speed rotation of the optical disc and enhances the mechanical strength of that portion, thereby improving the mechanical reliability at high speed rotation. it can.

According to the sixth aspect of the present invention, since the outer end of the magnetic plate is extended to the outside of the outer circumference of the clamp area of the substrate, the machine where stress is concentrated during high-speed rotation of the optical disk is machined. Thus, it is possible to provide an optical disc having a high mechanical strength and thus a high mechanical reliability during high-speed rotation.

[Brief description of drawings]

FIG. 1 is a sectional view showing a main part of an embodiment of a hub-adhering type optical disc of the present invention.

FIG. 2 is a cross-sectional view showing a main part of another embodiment of the hub-adhering type optical disk of the present invention.

FIG. 3 is a cross-sectional view showing a main part of an embodiment of a hub insertion type optical disc of the present invention.

FIG. 4 is a cross-sectional view showing the main parts of another embodiment of the hub insertion type optical disk of the present invention.

FIG. 5 is a sectional view showing a main part of an embodiment of a hubless type optical disc of the present invention.

FIG. 6 is a cross-sectional view showing the main parts of another embodiment of the hubless type optical disk of the present invention.

FIG. 7 is a cross-sectional view of essential parts showing a state in which a conventional hub-adhesion type optical disk is rotated by a spindle.

FIG. 8 is a cross-sectional view of essential parts showing a state where a crack is generated in the substrate by rotating the optical disc in the state shown in FIG.

FIG. 9 is a cross-sectional view of essential parts showing a state in which a conventional hub-insertion type optical disc is rotated by a spindle.

FIG. 10 is a cross-sectional view of essential parts showing a state in which a conventional hubless type optical disc is rotated by a spindle.

[Explanation of symbols]

 10A Optical disc 10B Optical disc 11 Recording layer 12 Central hole 13 Substrate 14 Hub 15 Ring member 16 Reinforcement ring 30A Optical disc 30B Optical disc 31 Recording film 32 Central hole 33 Substrate 33A Tapered surface 34 Metal hub 35 Clamp area 36 Data recording area 39 Metal support ring 40A Optical disc 40B Optical disc 41 Recording layer 42 Central hole 43 Substrate 44 Magnetic plate 45 Clamp area 46 Data recording area 49 Tapered surface

Claims (6)

[Claims] 1. A substrate having a recording layer formed inside and a central hole formed in the central portion, and a pair of clamping hubs attached to the central portion from both sides of the substrate, respectively. An optical disk, wherein a ring member whose outer diameter is gradually increased from the upper end of each hub toward the surface of the substrate is attached to each hub outer circumference. 2. A substrate having a recording layer formed inside and a central hole formed in the central portion, and a pair of clamping hubs attached to the central portion from both surfaces of the substrate, respectively. An optical disc, wherein a reinforcing ring having a width extending from the inner side to the outer side of the outer periphery of the hub is positioned inside the radial direction of the recording layer and provided inside the substrate. 3. A substrate having a recording film and a central hole formed on one surface, and a clamp hub fitted in the central hole from the recording film side of the substrate, wherein the clamping region of the substrate has a wall thickness. And an outer peripheral surface of the clamp area formed in a taper shape. 4. A substrate having a recording film and a central hole formed on one surface, and a clamp hub fitted into the central hole from the recording film side of the substrate, the substrate from the outer peripheral end of the hub. An optical disc having a support ring having a width extending to the outside of the clamp region, which is attached to the recording film. 5. A substrate having a recording layer formed inside and a central hole formed in the central portion, and a magnetic plate for clamping interposed in the substrate inside the recording layer with a gap therebetween. An optical disc in which the clamp region of the substrate is formed thicker than the data recording region outside thereof and the outer peripheral surface of the clamp region is tapered. 6. A substrate having a recording layer formed inside and a central hole formed in a central portion, and a magnetic plate for clamping interposed in the substrate inside the recording layer with a gap therebetween. An optical disc in which an outer end of the magnetic plate is provided outside an outer periphery of a clamp region of the substrate.