JP3022434U - Laminated optical disk - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a bonded optical disk which can easily make a surface judgment and can sufficiently secure a space for label printing. SOLUTION: In a bonded type optical disk in which at least one of two optical disks having a recording surface storing readable information is bonded with the recording surface of each optical disk inside, the two optical disks to be bonded The stack ring 5 is integrally formed on one of the outer surfaces of the optical disk.

Description

[Detailed description of the device]

[0001]

[Technical field to which the device belongs]

 The present invention relates to a structure of an optical disc such as a laminated digital video disc (hereinafter referred to as a DVD).

[0002]

[Prior art]

 2. Description of the Related Art Conventionally, compact discs (hereinafter referred to as CDs) or laser discs (hereinafter referred to as LDs) are known as optical discs that use optical means such as a laser to read a reproduction signal of information such as video and audio. Has been.

As shown in FIG. 3, a CD has a disk-shaped transparent substrate 1 made of PC (polycarbonate) resin or the like, one surface of which is a recording surface having irregularities as information, and a recording surface of the substrate 1. The reflective film 2 is made of aluminum or the like, and the protective film 3 is made of acrylic resin or the like and is provided on the reflective film 2. The irregularities on the recording surface of the transparent substrate 1 are formed by injection molding. Further, on the protective film 3 on the recording surface side of the CD, a label 4 on which information for identifying the CD itself is printed is printed.

A stack ring 5 is formed on the surface of the other transparent substrate 1. When stacking a plurality of manufactured CDs, the stack ring 5 maintains a predetermined space between the upper and lower CDs to prevent damage to the substrate surface side of the CDs in particular.

However, in such a CD structure, the surface of the substrate 1 made of resin and the surface of the aluminum reflective film having different hygroscopic properties may cause warpage.

In order to cancel out this warp and maintain the flatness of the disk stable, it is conceivable to adopt a structure in which two disks are bonded together.

The LD has such a two-layer bonding structure, and for example, two optical disk substrates (A, B) are bonded to each other with their recording surfaces inside. That is, as shown in FIG. 4, the LD is a transparent substrate 1 having a back surface as a recording surface, a reflective film 2 provided on the recording surface of the substrate 1, and a protective film provided on the reflective film 2. This is a structure in which two optical disks, which are roughly configured by 3 and 3, are bonded together via a rubber adhesive layer 6. Labels 4 are attached to the clamping areas inside the inner circumference lead-ins at the central portions of the front and back surfaces of the LD. In such an LD, a mark is made on an injection molding die for molding a substrate, and the marks A and B are used as a guide.

[0008]

[Problems to be solved by the device]

 However, in the DVD, which has been drawing attention in recent years, the inner lead-in area is small in order to make the recording area wider than that of the CD, and it is close to the clamping area. Will be done. In addition, if stacking is provided in the production process, the label cannot be printed due to the presence of the stack ring.

An object of the present invention is a DVD having a double-bonded structure, which provides a bonded optical disc that can easily determine each surface and has a sufficient space for label printing. To do.

[0010]

[Means for Solving the Problems]

 The bonded optical disk of the present invention is a bonded optical disk in which at least one of two optical disks having a recording surface storing readable information is bonded with the recording surface of each optical disk facing inward. It is characterized in that a stack ring is integrally formed on either one of the outer surfaces of the two optical disks to be combined.

Here, the stack ring is formed in a region between the clamping area and the lead-in area of the optical disc.

[0012]

[Embodiment of device]

 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

1A to 1C are views showing a first embodiment of a bonded optical disk of the present invention, and FIG. 1A is a plan view showing the surface of the bonded optical disk. It is a figure, (b) is a top view which shows the back surface of a bonding type optical disk, (c) is sectional drawing which shows the longitudinal cross section of a bonding type optical disc. Among the constituent elements of the optical disc according to the present embodiment, those common to the constituent elements of the conventional disc shown in FIGS. 3 and 4 are designated by the same reference numerals, and the description thereof will be omitted. To do.

The bonded optical disk according to this embodiment has a structure in which two optical disks are bonded to each other with the protective films 3 facing each other with the adhesive layer 6 interposed therebetween. In this embodiment, as shown in FIGS. 1A and 1C, a convex stack ring 5 is provided on one surface (A surface) of the bonded optical disk and the other surface (B surface) is provided. It is characterized by not providing stacking.

As shown in FIG. 1C, the stack ring 5 is formed integrally with the disk substrate 1 in the region from the outer peripheral edge of the clamping area CRA to the inner peripheral edge of the inner peripheral lead-in area RIA. It is practically inappropriate to form the stack ring 5 in other areas, for example, the lead-out area ROA. That is, if the stack ring 5 is formed in the clamping area CRA, the optical disk may be insufficiently clamped due to the presence of the convex stack ring 5, and the area from the lead-in area RIA to the lead-out area ROA may be insufficient. If the stack ring 5 is formed in the area, the load applied when the optical discs are integrated is concentrated near the stack ring 5, so that distortion may occur, and the distortion causes an inconvenience of insufficient information reproduction. .

In such a stack ring 5, a ring-shaped recess is usually formed in a mold for injection molding, and a resin such as PC is filled in the mold and solidified to form the transparent substrate 1. Formed in one piece.

Next, the shape and size of the stack ring 5 will be described with reference to FIG.

2A to 2E are schematic sectional views showing examples of the shape of the stack ring. The stack ring 5 shown in FIG. 2A has a substantially trapezoidal cross section, and its top is substantially parallel to the surface of the substrate 1. The height (height from the substrate 1 to the top) h of the stack ring 5 is in the range of 0.1 mm to 0.5 mm, more preferably in the range of 0.2 mm to 0.4 mm, and its width w is The range is 0.5 mm to 3 mm.

In the above embodiment, the top of the stack ring 5 is a flat surface, but the load concentrated when the optical discs are integrated can be supported by a surface of a certain size, and the load concentration can be avoided. In this sense, the stack ring 5 having a rectangular cross section shown in FIG. 2B also has the same effect.

In the above embodiment, the peripheral area of the stack ring 5 is a flat surface, but a recess may be formed along the stack ring 5 in the vicinity thereof. Of course, the depth and size of the concave portion can be appropriately determined in consideration of various aspects such as the mechanical strength of the optical disk and protection of the recording surface.

In the above embodiment, the stack ring 5 has a substantially rectangular cross-section as shown in FIGS. 2A and 2B, but as shown in FIGS. It may be triangular. With such a cross-sectional shape, the load is concentrated, but the contact area at the time of integration is small, so that the friction between the optical disks can be reduced.

Further, as shown in FIG. 2E, the stack ring 5 may have a semicircular cross section. In this case, since the top portion of the stack ring 5 includes the curved surface, the friction between the optical disks can be reduced almost in the same manner as in the cases of FIGS. 2C and 2D.

In the present embodiment, the stack ring 5 is provided at a predetermined position of the optical disc as a manufacturing component related to the bonded optical disc, so that the presence or absence of the stack ring is determined by an optical system such as a light emitting diode (LED). Since it is easy to distinguish the A side and B side of the optical disk by using the detecting means or the mechanical detecting means, it is possible to surely prevent erroneous reproduction of the A / B side and to rationalize the laminating production process. it can.

Further, in the present embodiment, since it is easy to determine the presence / absence of the stack ring, for example, screen printing or offset printing can be performed on the surface without the stack ring, compared to the content display on the optical disc case or the like. , It is possible to prevent the mistake of the disc.

[0025]

【Example】

 Hereinafter, an example of manufacturing the bonded optical disk according to the present invention will be described.

Two optical disks each having a diameter of 12 cm, an inner diameter of 15 mm and a thickness of 0.6 mm were attached to each other using a rubber-based adhesive. As shown in FIG. 1 (c), one of the optical discs has an outer peripheral edge of the clamping area CRA (more than 16.5 mm from the disc center) and an inner peripheral edge of the inner lead-in area RIA (more than 22 mm from the disc center). ), A stack ring 5 having a substantially trapezoidal cross section was formed by molding. The stack ring 5 had a height h of 0.3 mm and a width w of 1.0 mm.

A plurality of such bonded optical disks were manufactured and integrated. The stack ring could facilitate the integration of optical discs. Further, since the stack ring is formed away from the recording area, the recording area itself is not deformed such as distorted.

[0028]

[Effect of device]

 As described above, according to the present invention, by providing the stack ring on one surface of the two optical disks, it is possible to easily determine the surface by the presence or absence of the stack ring, and also to use the stack ring. The entire surface of the other side, which is not provided, can be used as the printing surface.

[Brief description of drawings]

1A to 1C are views showing a first embodiment of a bonded optical disc of the present invention, wherein FIG.
Is a plan view showing the surface of the bonded optical disk,
(B) is a plan view showing the back surface of the bonded optical disk, and (c) is a cross-sectional view showing a vertical section of the bonded optical disk.

2A to 2E are schematic cross-sectional views each showing an example of the shape of a stack ring.

FIG. 3 is a cross-sectional view showing a laminated structure of a CD.

FIG. 4 is a cross-sectional view showing a laminated structure of an LD.

[Explanation of symbols]

 1 Transparent substrate 2 Reflective film 3 Protective film 4 Label 5 Stack ring 6 Adhesive layer CRA Clamping area RIA Lead-in area ROA Lead-out area

Claims (2)

[Scope of utility model registration request] 1. A bonded type optical disk in which at least one of two optical disks having a recording surface storing readable information is bonded with the recording surface of each optical disk inside, and the two optical disks are bonded together. A laminated optical disk, wherein a stack ring is integrally formed on one of the outer surfaces of the optical disk. 2. The bonded optical disk according to claim 1, wherein the stack ring is formed in a region between a clamping area and a lead-in area of the optical disk.