JPH04209377A - Optical disk - Google Patents

Abstract

PURPOSE:To prevent the deformation of a disk substrate and the peeling of disk substrate and the center hub by forming a recessed part on a trunk part or a projected part on the central hole part, and fitting the projected part and the recessed part. CONSTITUTION:The center hub 10 is composed of the trunk part 11 and a flange part 12, and two recessed parts 13 are provided so as to face each other on the side surface of the trunk part 11. On the other hand, two projected parts 17 are provided so as to face each other on the periphery 16 of the central part 15 of the disk substrate 14, and the projected parts 17 and the recessed parts 13 are engaged. The center hub 10 is fitted into the central hole part 15, and the flange part 12 and the surface part of the disk substrate 14 are stuck and fixed by an adhesive, to form the optical disk. When the central hub 10 has rotary torque, a part where the projected part 17 and the recessed part 13 are engaged plays as a stopper, and the rotary torque is relaxed. Then, the deformation of the disk substrate 14 is eliminated, and the peeling between the trunk part 12 and the surface of the substrate 14 can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Objective of the Invention (Field of Industrial Application) The present invention relates to an optical disc, and particularly relates to an improvement of a center hub used in an optical disc.

(Prior Art) A conventional optical disc is constructed as shown in FIG. In the figure, 50 indicates a disk substrate.

A hole is formed in the center of the disk substrate 50,
A center hub 52 is fitted into the hole. As shown in FIG. 15, the center hub 52 has a cylindrical portion 5.
4 and a disc-shaped flange 56. Usually, an adhesive member such as an adhesive is provided on the surface of the flange portion 56 to join the disk substrate 50 and the center hub 52 together.

(Problems to be Solved by the Invention) However, in the optical disc having such a configuration, if the surface precision of the flange portion 56 of the center hub 52 is poor, that is, if the surface of the flange portion 56 is not smooth, the disc substrate 50 and There is a problem in that the disk substrate 50 is deformed when the center hub 52 is joined. For this reason, attempts have been made to reduce the area of the flange 56 of the center hub 52 to reduce the contact area between the disk substrate 50 and the flange 56, thereby preventing the disk substrate 50 from deforming.

However, in this case, the bonding strength between the disk substrate 50 and the center hub 52 becomes weak, and the center hub 52 becomes easily peeled off from the disk substrate 50. Particularly, when rotational torque is applied to the center hub 52, separation of the center hub 52 from the disk substrate 50 becomes noticeable.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an optical disc in which the disc substrate is not deformed and separation between the disc substrate and the center hub can be prevented.

[Structure of the Invention (Means for Solving the Problems) The present invention provides a method for fitting a center hub consisting of a cylindrical portion and a flange into a central hole of a disk substrate, and connecting the flange and the disk substrate via an adhesive layer. In the optical disc which is fixed to the cylindrical portion, a convex portion or a concave portion is formed on one of the cylindrical portion and the hole portion, and a concave portion or a convex portion that fits with the convex portion or the concave portion is formed on the other. Provides an optical disc featuring the following.

The present invention also provides an optical disc in which a center disk comprising a cylindrical portion and a flange is fitted into a central hole of a disk substrate, and the flange and the disk substrate are fixed via an adhesive layer. The present invention provides an optical disc characterized in that the adhesive layer extends on the surface area of the disc substrate outside the flange by a width at least twice the thickness of the adhesive layer.

(Function) According to the optical disc of the present invention, a concave part and a convex part are provided in the cylindrical part of the center hub and the central hole part of the disc substrate, and the center hub and the disc substrate are joined by engaging these parts. Thereby, when a rotational torque is applied to the portion where the recess and the projection are engaged, the rotational torque is relieved by acting as a stopper.

Further, according to the optical disc of the present invention, the adhesive layer extends on the surface area of the disc substrate outside the flange by a width at least twice the thickness of the adhesive layer.

Thereby, when a rotational torque is applied to a region extending by a width at least twice the thickness of the adhesive layer, the region serves as a stopper and relieves the rotational torque.

Therefore, the contact area between the flange of the center hub and the disk substrate is reduced (to prevent deformation of the disk substrate, while
The center hub and the disk substrate can be firmly joined, and separation between them can be sufficiently prevented.

(Example) Hereinafter, an example of the present invention will be specifically described with reference to the drawings.

Embodiment 1 FIG. 1 is an explanatory diagram showing one embodiment of a center hub used in the optical disc of the present invention. The center hub 10 is
It is composed of a cylindrical portion 11 and a collar portion 12. Two recesses 13 are provided on the side surface of the cylindrical portion 11 so as to face each other. Note that the flange portion 12 is formed with a narrow width in order to reduce the contact area with the disk substrate. FIG. 2 is an explanatory diagram showing one embodiment of a disk substrate used in the first disk of the present invention. Two protrusions 17 are provided on the circumferential surface 16 of the central hole 15 of the disk substrate 14 so as to face each other. The center hub 10 is fitted into the center hole 15 of the disk substrate 14 so that the convex portion 17 of the disk substrate 14 and the four parts 13 of the center hub 10 are engaged, and the flange 12 and the surface of the disk substrate are bonded with adhesive or the like. By gluing and fixing the tip disc 1 as shown in Fig. 3,
is configured.

In the optical disc having such a configuration, when a rotational torque is applied to the center hub 10, the portion where the convex portion and the four portions engage serves as a stopper and relieves the rotational torque, so that the flange portion 12 and the surface of the disk substrate Peeling between the two can be prevented.

In this embodiment, the center hub 10 has a recess]3,
Although the convex portions] 7 are provided on the disk substrate 14,
It goes without saying that the same effect can be obtained by providing a convex portion on the center hub and a concave portion on the disk substrate.

Embodiment 2 FIG. 4 is an explanatory diagram showing another embodiment of the center hub used in the optical disc of the present invention. The center hub 20 includes a cylindrical portion 21 and a flange portion 22. Tsuba 22
A plurality of projections and depressions 23 are formed on the circumferential surface. Note that the flange portion 22 is formed with a narrow width in order to reduce the contact area with the disk substrate. By fitting the center hub 20 into the central hole 25 of the disk substrate 24 shown in FIG. 5, and fixing the flange 22 and the surface of the disk substrate 24 with adhesive by providing an adhesive layer, an optical disk as shown in FIG. It consists of 2. The adhesive layer provided between the flange 22 and the disk substrate 24 is attached to the flange 2 as shown in FIG.
The adhesive layer 26 extends on the outer surface area of the disk substrate 24 by a width at least twice the thickness of the adhesive layer 26 . here,
The reason why the thickness is at least twice the thickness of the adhesive layer 26 is that if the width extends less than the thickness of the adhesive layer 26, the rotational torque cannot be sufficiently alleviated when rotational torque is applied to the center hub. It is from.

In an optical disc having such a configuration, when a rotational torque is applied to the center hub 20, the thickness of the adhesive layer is at least 2
Since the region extending by the double width serves as a stopper and relieves the rotational torque, separation between the flange portion 22 and the surface of the disk substrate 24 can be prevented.

In this embodiment, a center hub 20 is used in which a plurality of irregularities are formed on the circumferential surface of the collar portion 22.
Similar effects can be obtained by using a center hub 30 whose flange 32 has a polygonal shape as shown in FIG. In this case, as shown in FIG. 9, a disk substrate 40 is used in which a stepped portion 42 is formed around the hole 41 in accordance with the shape of the center hub to be fitted, and has a step portion 42 having approximately the same shape as the flange portion thereof. As a result, an optical disc 3 having a structure as shown in FIG. 10 is obtained. This optical disc 3 can achieve a higher effect in alleviating rotational torque when rotational torque is applied to the center hub.

In addition, the center hub 20 with the unevenness 23 formed on the circumferential surface of the flange 22 shown in FIG. 4 is fitted into the center hole 45 of the disk substrate 44, which has a circular stepped portion 43 as shown in FIG. Similar effects can also be obtained with the optical disc 4 obtained by providing an adhesive layer by filling the recesses 46 formed by the stepped portions 43 and the unevenness 23 with an adhesive. The optical disc 4 is configured such that the flange of the center hub 20 is housed in a stepped portion 43 of a disc substrate 44, as shown in FIG.

In the first and second embodiments described above, a single-sided optical disc is described, but the optical disc of the present invention can also be applied to a double-sided optical disc in which two optical discs are symmetrically bonded together.

[Effects of the Invention] As explained above, in the optical disc of the present invention, there is no deformation of the disc substrate, and separation between the disc substrate and the center hub can be prevented.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing one embodiment of the center hub used in the optical disc of the present invention, FIG. 2 is an explanatory diagram showing one embodiment of the disc substrate used in the optical disc of the present invention, and FIG. 4 and 8 are explanatory views showing one embodiment of the optical disc of the present invention, and FIGS. 5, 9, and 8 are explanatory views showing other embodiments of the center hub used in the optical disc of the present invention. FIG. 11 is an explanatory view showing other embodiments of the disk substrate used in the optical disk of the present invention, FIGS. 6 and 10. FIG. 12 is an explanatory diagram showing another embodiment of the optical disc of the present invention, FIG. 7 is a sectional view of the optical disc shown in FIG. 6, and FIG.
The drawings are a sectional view of the optical disc shown in FIG. 12, FIG. 14 is an explanatory diagram showing a conventional optical disc, and FIG. 15 is an explanatory diagram showing a center hub used in the conventional optical disc. 1.2, 3.4... optical disc, 10, 20.30.
...Center hub, 11.21...Cylinder part, 12,22
．． 32... Flange part, 13... Concave part, 14, 24, 40
゜44...Disk board, 15, 25.41.4'5
...Central hole, 16...Surrounding surface, 17...Protrusion, 2
3... Irregularities, 26... Adhesive layer, 42.43... Step portion. Applicant's Representative Patent Attorney Takehiko Suzue Figure 10 Figure 11 Figure 2 Figure 13 Figure 15

Claims (2)

[Claims] (1) In an optical disc in which a center hub consisting of a cylindrical part and a flange part is fitted into a central hole of a disc substrate, and the flange part and the disc substrate are fixed via an adhesive layer, the cylindrical part and the hole part An optical disc characterized in that a convex portion or a concave portion is formed on one of the two, and a concave portion or a convex portion that fits into the convex portion or the concave portion is formed on the other side. (2) In an optical disc in which a center hub consisting of a cylindrical portion and a flange is fitted into a central hole of a disk substrate, and the flange and the disk substrate are fixed via an adhesive layer, the adhesive layer An optical disc characterized in that a width at least twice the thickness of the adhesive layer extends on the surface area of the disc substrate outside the flange.