JPH09153231A - Optical disk - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical disk of a sticking type which is large in the permissible value of the misalignment between upper and lower disks at the time of sticking and the amt. of protrusion of sticking members from layers to be stuck and allows the easy identification of the surfaces to be provided with the reflection layers of disk substrates before adhesion of the reflection layer and the surface opposite thereto. SOLUTION: Two sheets of such optical disks 2 which consist of the substrates 19, the reflection layers 20 and protective layers 21, have central holes of the bores changing from the surface positions of the substrate side disk toward the surface position of the protective layer side disk and have another sections of the bore of the central hole smaller than the bore of the central hole in the surface position on the protective layer side disk are stuck to each other to form one sheet of the optical disk.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of an optical disc such as a video disc or a compact disc capable of reproducing information by irradiating a laser beam and a disc memory capable of recording / reproducing / erasing information.

[0002]

2. Description of the Related Art In a conventional optical disc, particularly an optical disc having a structure in which two optical discs are bonded together to form one optical disc, the cross-sectional shape in the radial direction on the side of the center hole of the optical disc as shown in FIG. 2. Description of the Related Art There is known a structure in which two optical discs each having a shape cut out in a direction perpendicular to the surface of the optical disc are attached.

21 and 22 are cross-sectional views when the bonding disk 23 is set on the chucking portion of the player. A turntable 13 is provided on the output shaft 12 of the disk motor, and further has a cone 16 for centering the disk and a magnet 14 for fixing the disk, and a bonded disk 23 by a clamper 18 for fixing the disk.
Is fixed to the disc motor 11. The clamper 18 has a magnetic material 17, and is fixed to the disc motor 11 via the disc 23 by the magnetic force of the magnet 14 provided on the turntable 13. The cone 16 is pushed up to the side opposite to the turntable 13 by the elastic material 15. The cone 16 is pushed down by setting the bonding disk 23, and the center hole of the bonding disk 23 comes into contact with the cone 16 to center the disk.

As another conventional example, in an optical disk as shown in FIGS. 25 and 26, two optical disk substrates 19 each having a central hole are opposed to each other and are bonded by an adhesive (bonding member) 25. A configuration in which an adhesive outflow preventing ridge 26 is provided on at least one of the outer peripheral edge and the inner peripheral edge of the bonding surface of the optical disk substrate,
A proposal has been made for the purpose of preventing the sticking member from protruding (see, for example, Japanese Patent Laid-Open No. 208839/1990).

[0005]

In the former of those described in the prior art, there is a problem that the bonded disc cannot be set in the chucking portion when the bonded disc has a large amount of misalignment. Further, even when the amount of sticking displacement is small, there is a problem that the sticking disc cannot be properly fixed to the turntable when the sticking member protrudes from the sticking layer at the time of sticking. .

FIG. 23 shows a cross-sectional view of a bonded disc having a sticking deviation, and FIG. 24 shows a cross-sectional view of the stuck disk having a sticking deviation when set in a chucking portion. If there is a sticking error in the sticking disk 23, the sticking disk 23 will come from the disk motor side.
The entered cone 16 hits the disk on the side opposite to the disk motor, and proper centering cannot be performed. If the displacement is further large, the bonded disc 23 cannot be properly fixed to the turntable 13. Therefore, it is necessary to manage the amount of sticking displacement in the sticking process at the time of manufacturing the disc to be small. Even if the amount of sticking displacement is small, if the sticking member sticks out of the sticking layer during sticking, the inner diameter of the disk becomes small, and if the amount is large, the sticking disk 23 is properly placed on the turntable 13. It cannot be fixed.

Further, in the latter of those described in the prior art, although it is possible to prevent the sticking member from protruding to some extent, unless the usage amount of the sticking member is strictly controlled. It is unavoidable that the sticking member slightly protrudes. Further, in this conventional example, no consideration or ingenuity has been made on increasing the allowable value of the amount of sticking displacement of the stuck disk as described above.

The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to allow a sticking deviation in a sticking step in manufacturing a stuck disk. It is an object of the present invention to provide a bonded type optical disc that can increase the allowable value of the amount of sticking out of the sticking member from the sticking layer.

[0009]

In order to achieve the above object, an optical disk according to the present invention comprises a first optical disk having the following structure and a second optical disk having the same structure. The structure has a structure in which the protective film sides are opposed to each other and are bonded together.

The first optical disk comprises a transparent substrate that transmits light, an information storage layer formed on one surface of the transparent substrate, and a protective layer formed on the information storage layer. For the purpose of increasing the permissible values of the disc sticking displacement amount and the sticking member protrusion amount, between the surface position of the optical disc on the transparent substrate side of the laminated disc and the surface position of the optical disc on the protective layer side. It has a central hole whose inner diameter is changed and has another position where the inner diameter of the central hole is smaller than the inner diameter of the central hole at the surface position of the optical disk on the protective layer side.

The structure of the center hole of the first optical disk is as follows:
The cross-sectional shape of the optical disk in the radial direction on the side of the central hole may be a shape that is merely inclined so that the shape can be easily manufactured.

In the case where the cross-sectional shape is a shape that is merely inclined, a burr may be formed on the inner wall of the center hole at the disk surface position on the transparent substrate side in the optical disk manufacturing process. Therefore, when it is subjected to a process such as deletion, the cross-sectional shape, that is, the cross-sectional shape of the optical disc in the radial direction on the side of the center hole is inclined from the surface position of the optical disc on the side of the transparent substrate. In addition, the shape may be such that it is inclined from the surface position of the optical disc on the protective layer side.

In addition to the above-mentioned object, in the case of attaching a reflection layer for reflecting a light beam on a transparent substrate, it is necessary to clarify the distinction between the surface on which the reflection layer is attached and the opposite surface. The cross-sectional shape may be a stepped shape.

Further, in order to make the handling of the optical disc safe and reduce the damage of the cone of the chucking portion of the player, the cross-sectional shape may be curved.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows the structure of the optical disc of the present invention before being attached. This figure shows a partial sectional view in the radial direction on the side of the center hole of the disk. Reference numeral 19 in the figure denotes a transparent substrate, which is made of glass or synthetic resin. An information signal such as a minute information pit is formed in advance on one surface of the transparent substrate 19 by molding, and then a metal reflection film 20 such as aluminum is coated on the transparent substrate 19 to form an information storage layer. ing. Metal reflective film 20
A protective coating of resin or the like is applied on the top surface to form a protective layer 21.

The structure of the center hole of the optical disk is such that the inner diameter changes from the surface position of the optical disk on the transparent substrate side to the surface position of the optical disk on the protective layer side, and the surface of the optical disk on the protective layer side. With respect to the inner diameter of the central hole at the position, the inner diameter of the central hole is smaller than the inner diameter.

FIG. 2 is a partial cross-sectional view of an embodiment of the present invention in which the two optical disks shown in FIG. 1 are bonded together with their protective layers facing each other to form one optical disk. FIG. 3 shows a cross-sectional view when the bonding disk 23 is set on the chucking portion of the player. The output shaft 12 of the disc motor 11 is provided with a turntable 13, a cone 16 for disc centering and a disc fixing magnet 14 are provided, and the disc 23 is fixed to the disc motor 11 by a clamper 18 for fixing the disc. To be done. The clamper 18 is fixed to the disc motor 11 via the disc 23 by the magnetic force of the magnet 14 having the magnetic material 17 and provided on the turntable 13. The cone 16 is pushed up to the side opposite to the turntable 13 by the elastic material 15. The cone 16 is a disc 23
Is pushed down by setting the disc 23
The centering of the disc is performed by the contact between the center hole of the cone and the cone 16.

FIG. 4 shows an embodiment of the present invention corresponding to claim 2. The configuration of the center hole of the optical disk is such that the inner diameter of the center hole at the position of the bonding surface of the bonded disk (the surface position of the optical disk on the protective layer side in the optical disk before bonding) is the maximum inner diameter φmax, and The inner diameter of the center hole at the surface position of the bonded disk (the surface position of the optical disk on the transparent substrate side in the optical disk before bonding) becomes the minimum inner diameter φmin, and
The shape in which the change in the inner diameter changes substantially linearly, in other words, the cross-sectional shape of the optical disk in the radial direction on the side of the central hole is a shape that is merely inclined.

FIG. 5 shows the relationship between the cone and the bonded disc when the bonded disc shown in FIG. 4 is set in the chucking portion of the player. In this case, since there is no sticking displacement in the stuck disk, no special problem occurs in setting to the chucking portion.

FIG. 6 shows a partial cross-sectional view of the bonded disk shown in FIG. 4 when the bonded disk has a slight bonding deviation. The dotted line in the figure shows the case of a conventional pasting disc, which corresponds to the pasting disc of the present invention shown by the solid line, and when the pasting disc of the present invention has a pasting discrepancy, the past pasting disc It shows how much the sticking disc will be stuck.

FIG. 7 shows a cone when the laminated disc shown in FIG. 6 is set in the chucking portion of the player with the maximum discrepancy that can be allowed due to the relationship between the pasted disc 23 and the cone 16. Shows the relationship between the bonded disc and the bonded disc. The dotted line in the figure corresponds to the case of the present invention shown by the solid line as in FIG. 6, but the sticking deviation here indicates the allowable sticking deviation from the above. Comparing the case with the solid line and the case with the dotted line,
Even if the sticking deviation in the case of the solid line is larger than that in the case of the dotted line, the cone 16 that has entered the bonding disk 23 from the turntable 13 side hits the bonding disk 23 on the opposite side of the turntable 13 and is appropriate. The centering can be done and the bonded disc 23 can be used as the turntable 13.
You can see that it can be fixed properly. In other words, the structure of the center hole is changed from the surface position of the bonded disk (the surface position of the optical disk on the transparent substrate side in the optical disk before bonding) to the disk bonding surface (the protective layer side in the optical disk before bonding). The inner diameter of the central hole changes up to the surface position of the optical disk, and the inner diameter of the central hole is smaller than the inner diameter of the central hole at the position of the bonding surface (in this embodiment, Has a surface position of the bonded disk), it is possible to increase the allowable value of the disk sticking displacement amount.

Further, with the above-mentioned structure, a slight space is formed in the inner wall portion of the center hole after attachment, and the protrusion of the attachment member from the attachment layer at the time of attachment is Since it is possible to stay in the space to some extent, the allowable value of the protruding amount of the attaching member can be increased.

Further, the above-mentioned structure is related to the inner diameter of the center hole of the transparent substrate of the optical disc before bonding.
Since it is to form the change of the inner diameter in the direction perpendicular to the in-plane direction of the optical disk, and it is easy to confirm the change, it is necessary to confirm the change of the inside diameter of the transparent substrate. It is also possible to easily distinguish the surface.

Further, in the present embodiment, since the cross-sectional shape of the optical disc in the radial direction on the side of the central hole is a mere inclination, a disc having such a shape is produced. Even if it is produced by using a disk similar to the conventional one to perform processing such as cutting processing on its center hole, it is produced using a mold such that the inner wall of the center hole has the above-mentioned configuration. However, in any case, it can be easily manufactured.

FIG. 8 shows another embodiment of the present invention.
Corresponding to claim 3. The configuration of the center hole of the optical disk is such that the inner diameter of the center hole at the position of the bonding surface of the bonded disk (the surface position of the optical disk on the protective layer side in the optical disk before bonding) is the maximum inner diameter φmax, and The inner diameter of the central hole at a certain position from the position of the bonding surface to the surface position of the bonded disk (the surface position of the optical disk on the transparent substrate side in the optical disk before bonding) is the minimum inner diameter φmin, and A shape in which the change of the inner diameter changes substantially linearly, in other words, a shape in which the cross-sectional shape of the optical disk in the radial direction on the side of the central hole has an inclination from both the surface and the bonding surface of the optical disk. Has become.
Such a shape is formed because, in the optical disc according to the embodiment shown in FIG. 4, burrs are formed on the inner wall of the center hole at the disc surface position on the transparent substrate side in the optical disc manufacturing process before the bonding. This is the case when a process such as scraping off the burr is performed. Conversely, with such a shape, it is possible to obtain a good optical disk that has been subjected to the burr removal processing.

FIG. 9 shows the relationship between the cone and the bonded disc when the bonded disc shown in FIG. 8 is set in the chucking portion of the player. In this case, since there is no sticking displacement in the stuck disk, no special problem occurs in setting to the chucking portion.

FIG. 10 shows a partial cross-sectional view of the bonded disk in the case where the bonded disk shown in FIG. 8 has a slight bonding deviation. The dotted line in the figure
Similar to that shown in FIG. 6, the case of a conventional pasting disk is shown.

FIG. 11 shows a cone when the laminated disc shown in FIG. 10 is set in the chucking portion of the player with the maximum discrepancy that can be allowed due to the relation between the laminated disc 23 and the cone 16. Shows the relationship between the bonded disc and the bonded disc. The difference in pasting here is
This is the same as that shown in FIG. 7 and shows the allowable sticking deviation. Comparing the case of the embodiment of the present invention (solid line) with the case of the conventional laminating disk (dotted line), even if the sticking deviation is larger in the case of the solid line than in the case of the dotted line, Turn the bonded disc 23 into the turntable 1
It turns out that it can be properly fixed to 3. Furthermore, in the embodiment shown in FIG. 11, the cross-sectional shape of the optical disc in the radial direction on the side of the center hole is such that the optical disc is inclined not only from the bonding surface of the optical disc but also from the surface side of the optical disc. Therefore, a part of the inner wall portion of the center hole of the optical disc that was in contact with the cone in the case of FIG. 7 is removed, and as a result, the sticking is performed more than in the embodiment shown in FIG. It is possible to slightly increase the allowable value of the amount of misalignment.

Further, as in the case of FIG. 7, a slight space is formed in the inner wall portion of the center hole after the optical disc is attached, so that the permissible value of the protruding amount of the attaching member can be increased. .

Further, since it is easy to confirm the change in the inner diameter of the center hole of the transparent substrate of the optical disc before the bonding in this embodiment as well,
It is possible to easily distinguish the surface of the transparent substrate on which the reflective layer is attached from the surface opposite to the surface.

FIG. 12 shows another embodiment of the present invention and corresponds to claim 4. The configuration of the center hole of the optical disk is such that the inner diameter of the center hole at the position of the bonding surface of the bonded disk (the surface position of the optical disk on the protective layer side in the optical disk before bonding) is the maximum inner diameter φmax, and The inner diameter of the center hole at the surface position of the laminated disc (the surface position of the optical disc on the transparent substrate side in the optical disc before bonding) is the minimum inner diameter φmin, and the change of the inner diameter is as shown in FIG. The shape is changing.

With such a shape, since the shape of the center hole of the optical disk is not merely inclined but has a clear step, it is possible to more easily confirm the change in the inner diameter of the center hole. It is possible to more easily distinguish the surface of the transparent substrate on which the reflective layer is attached and the surface opposite to the surface.

FIG. 13 shows the relationship between the cone and the bonded disc when the bonded disc shown in FIG. 12 is set in the chucking portion of the player. In this case, since there is no sticking displacement in the stuck disk, no special problem occurs in setting to the chucking portion.

FIG. 14 shows a partial cross-sectional view of the bonded disk shown in FIG. 12 when the bonded disk has a slight bonding deviation. The dotted line in the figure is the same as that shown in FIG. 6 and the like, and shows the case of the conventional pasting disk.

FIG. 15 shows a case where the laminating disc shown in FIG. 14 is set in the chucking portion of the player with the maximum laminating discrepancy which is allowable due to the relation between the laminating disc 23 and the cone 16. , Shows the relationship between the cone and the bonded disc. The sticking misalignment here is similar to that shown in FIG. 7 and the like, and shows an allowable sticking misalignment. Comparing the case of the embodiment of the present invention (solid line) with the case of the conventional laminating disk (dotted line), even if the sticking deviation is larger in the case of the solid line than in the case of the dotted line, The laminating disc 23 can be properly fixed to the turntable 13. That is, it can be seen that by adopting the configuration of the present invention, it is possible to increase the allowable value of the amount of sticking displacement.

Also, as in the case of FIG. 7 and the like, since a slight space is formed in the inner wall portion of the center hole after the optical disc is attached, the allowable value of the protruding amount of the attaching member can be increased. it can.

FIG. 16 shows another embodiment of the present invention and corresponds to claim 5. The configuration of the center hole of the optical disk is such that the inner diameter of the center hole at the position of the bonding surface of the bonded disk (the surface position of the optical disk on the protective layer side in the optical disk before bonding) is the maximum inner diameter φmax, and The inner diameter of the central hole at a certain position from the position of the bonding surface to the surface position of the bonded disk (the surface position of the optical disk on the transparent substrate side in the optical disk before bonding) is the minimum inner diameter φmin, and The shape of the inner diameter changes in a curve as shown in FIG. Such a shape is formed when the corners formed on the inner wall of the center hole are shaved and rounded in the manufacturing process of the optical disc as shown in FIGS. 4, 8 and 12, or by using a mold. When the desired shape (for example, the shape where the inner wall of the central hole has a step as shown in FIG. 12) does not appear clearly when it is manufactured by injection or the like, or when it is designed to have an aesthetic appearance, etc. Is.

FIG. 17 shows the relationship between the cone and the bonded disc when the bonded disc shown in FIG. 16 is set in the chucking portion of the player. In this case, since there is no sticking displacement in the stuck disk, no special problem occurs in setting to the chucking portion.

FIG. 18 shows a partial cross-sectional view of the bonded disk in the case where the bonded disk shown in FIG. 16 has a slight bonding deviation. The dotted line in the figure is the same as that shown in FIG. 6 and the like, and shows the case of the conventional pasting disk.

FIG. 19 shows a case where the bonded disc shown in FIG. 18 is set in the chucking portion of the player with the maximum bonding deviation allowable from the relationship between the bonded disc 23 and the cone 16. , Shows the relationship between the cone and the bonded disc. The sticking misalignment here is similar to that shown in FIG. 7 and the like, and shows an allowable sticking misalignment. Comparing the case of the embodiment of the present invention (solid line) with the case of the conventional laminating disk (dotted line), even if the sticking deviation is larger in the case of the solid line than in the case of the dotted line, The laminating disc 23 can be properly fixed to the turntable 13. That is,
It can be seen that, by adopting the configuration of the present invention, it is possible to increase the allowable value of the amount of sticking displacement.

Further, as in the case of FIG. 7 and the like, since a slight space is formed in the inner wall portion of the center hole after the optical disc is attached, the permissible value of the protruding amount of the attaching member can be increased. it can.

Further, by making the shape of the inner wall of the center hole into a curved shape as shown in FIG. 19, the handling of the optical disk is made safe and the damage to the cone of the chucking portion of the player is reduced. It becomes possible.

[0043]

The surface of the optical disc on the transparent substrate side comprises a transparent substrate which transmits light, an information storage layer formed on one side of the transparent substrate, and a protective layer formed on the information storage layer. It has a central hole whose inner diameter changes from the position to the surface position of the optical disc on the protective layer side, and makes the inner diameter of the central hole of the optical disc on the protective layer side a predetermined inner diameter, which is smaller than the predetermined inner diameter. Attaching a bonded disc by providing a structure in which a first optical disc having a structure having a part and a second optical disc having a similar structure are bonded with their protective layer sides facing each other. It is possible to increase the allowable values of the shift amount and the sticking-out amount of the sticking member.

[Brief description of the drawings]

FIG. 1 is a diagram showing a structure of a disc of the present invention before being attached.

FIG. 2 is a diagram showing the structure of the disc of the present invention after being attached.

FIG. 3 is a cross-sectional view showing a state in which the disc of the present invention after being attached is fixed to a chucking portion of a player.

FIG. 4 is a diagram showing a structure of a central hole after pasting according to the first embodiment of the present invention.

FIG. 5 is a cross-sectional view showing the relationship between the bonded disc and the cone when the disc of the present invention after being attached to the first embodiment of the present invention is set in the chucking portion of the player.

FIG. 6 is a diagram showing a structure of a central hole in the case where there is a deviation at the time of attachment according to the first embodiment of the present invention.

FIG. 7 is a cross-sectional view showing a relationship between a pasted disc and a cone when the disc according to the first embodiment of the present invention is set in a chucking portion of a player when there is a discrepancy during pasting.

FIG. 8 is a view showing a structure of a center hole after pasting according to a second embodiment of the present invention.

FIG. 9 is a cross-sectional view showing the relationship between the bonded disc and the cone when the disc of the present invention after being attached to the second embodiment of the present invention is set in the chucking portion of the player.

FIG. 10 is a diagram showing a structure of a center hole in the case where there is a deviation at the time of attachment according to the second embodiment of the present invention.

FIG. 11 is a cross-sectional view showing a relationship between a pasted disc and a cone when the disc according to the second embodiment of the present invention is set in a chucking portion of a player in the case where there is a discrepancy during pasting.

FIG. 12 is a view showing the structure of a center hole after attachment according to the third embodiment of the present invention.

FIG. 13 is a cross-sectional view showing the relationship between the bonded disc and the cone when the disc of the present invention after being attached to the third embodiment of the present invention is set in the chucking portion of the player.

FIG. 14 is a diagram showing a structure of a center hole when there is a deviation at the time of sticking according to the third embodiment of the present invention.

FIG. 15 is a cross-sectional view showing a relationship between a pasted disc and a cone when the disc according to the third embodiment of the present invention is set in a chucking portion of a player when there is a discrepancy during pasting.

FIG. 16 is a diagram showing a structure of a center hole after being attached according to a fourth embodiment of the present invention.

FIG. 17 is a cross-sectional view showing the relationship between the bonded disc and the cone when the disc of the present invention after being attached to the fourth embodiment of the present invention is set in the chucking portion of the player.

FIG. 18 is a diagram showing a structure of a center hole in the case where there is a deviation at the time of attachment according to the fourth embodiment of the present invention.

FIG. 19 is a cross-sectional view showing a relationship between a pasted disc and a cone when the disc according to the fourth embodiment of the present invention is set in a chucking portion of a player when there is a discrepancy during pasting.

FIG. 20 is a view showing a structure of a center hole after pasting a conventional disc.

FIG. 21 is a view showing the relationship between the pasted disc and the cone when the pasted pasted disc is set in the chucking portion of the player.

FIG. 22 is a cross-sectional view showing a state where the pasted conventional disc is fixed to the chucking portion of the player.

FIG. 23 is a diagram showing a structure of a center hole when there is a deviation when pasting a conventional disc.

FIG. 24 is a cross-sectional view showing the relationship between the pasted disc and the cone when the conventional disc is set in the chucking portion of the player when there is a discrepancy during pasting.

FIG. 25 is a sectional view showing the structure of another conventional disc.

FIG. 26 is a sectional view showing the structure of another conventional disc.

[Explanation of symbols]

 11 Disk Motor 12 Output Shaft 13 Turntable 14 Magnet 15 Elastic Body 16 Cone 17 Magnetic Material 18 Clamper 19 Substrate 20 Reflective Layer 21 Protective Layer 22 Adhesive Layer 23 Laminated Disc 24 Recording Layer 25 Adhesive 26 Protrusion

Claims (5)

[Claims] 1. An optical disk comprising a transparent substrate that transmits light, an information storage layer formed on one surface of the transparent substrate, and a protective layer formed on the information storage layer, with their protective layer sides facing each other. A bonded-type optical disk in which two pieces are bonded has a central hole whose inner diameter changes between the surface position of the optical disk on the transparent substrate side and the surface position of the optical disk on the protective layer side, and The inner diameter of the center hole of the optical disc is a predetermined inner diameter, and a first optical disc having a portion having an inner diameter smaller than the predetermined inner diameter, and a second optical disc having the same configuration as the first optical disc are provided on the protective layer side. An optical disc having a structure in which the two are opposed to each other and bonded together. 2. The optical disk according to claim 1, wherein the cross-sectional shape in the radial direction on the side of the central hole is an inclined shape. 3. The cross-sectional shape is a shape inclined from the surface position of the optical disk on the transparent substrate side, and a shape inclined from the surface position of the optical disk on the protective layer side. The optical disc according to item 1. 4. The optical disc according to claim 1, wherein the cross-sectional shape is a stepped shape. 5. The optical disk according to claim 1, wherein the cross-sectional shape is a curved shape.