JP3264820B2 - Laminated disk, method of manufacturing the same, and disk forming apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technology relating to a bonded type disc manufactured by laminating and bonding two separately formed discs such as a DVD (Digital Video Disc) and the like. More particularly, the present invention relates to a structure of a single-sided reading type bonded disc, a method of manufacturing the same, and a disk forming apparatus for forming two disks constituting the bonded type disc.

[0002]

2. Description of the Related Art In recent years, a bonded disc has been developed in which first and second discs formed separately from each other are integrated with each other for the purpose of improving recording capacity and the like. Have been. Such a bonded disc has two signal recording surfaces, which enables recording of a feature-length movie or large-capacity data.
When used as a general movie or data recording disc, only one recording surface is used, and it is a single-sided reading type. The single-sided reading type bonded disc has a structure in which a second disc having no signal recording surface is superimposed and adhered to a signal recording surface formed on one surface of the first disc. In general, a first disk and a second disk each having a thickness of less than half of the target disk are each resin-molded using a mold similar to a normal single-structure disk, and the first disk is formed. After forming a reflective film and a protective film on the signal recording surface formed on the disc,
It is formed by overlapping and adhering both disks so that the signal recording surface is covered by the second disk.

By interposing an adhesive layer between the second disk of the first disk and the other disk, there is an advantage that the thickness error between the two disks can be absorbed, but the type (characteristic) of the adhesive In some cases, the thickness of the adhesive layer must be reduced depending on the size of the disc and the size of the disc. For example, in the case of a DVD or the like using an ultraviolet curable adhesive, it is difficult to apply a thick coating due to the characteristics of the photopolymer used, and it is difficult to secure a thickness of the adhesive layer of 40 μm or more.

However, when the thickness of the adhesive layer is reduced,
Despite satisfying the required shape and dimensional accuracy of the first and second discs alone, when they are bonded together to produce a bonded disc, poor adhesion and poor thickness dimensions occur. A new problem has been found that is easy to perform and increases the defective product rate. Although such a problem is not so serious at the prototype stage, it is a very serious problem when considering mass production.

[0005]

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to achieve excellent mass productivity by suppressing the rejection rate during manufacturing. It is an object of the present invention to provide a single-sided reading type bonded disc having a novel structure, a method of manufacturing the same, and a disc forming die.

[0006]

According to the present invention, the inventors of the present invention have conducted a number of experiments and conducted intensive studies. As a result, the problem of the defective product rate as described above has been raised during the formation of the first and second disks constituting the bonded disk. This is based on the knowledge that it is likely to be caused by minute burrs to be formed.

That is, the molding dies for forming the first and second disks generally comprise a pair of molding dies (fixed mold and movable mold) mounted on a fixed plate and a movable plate of a mold clamping device, respectively. By setting a stamper on the cavity forming surface of one of the molds and matching the mold, a mold cavity is formed between the mold matching surfaces,
In general, the cavity forming surface of each mold is a mirror surface plate, and a bush, a female cutter sleeve, an ejector sleeve, a stationary sleeve, and a stamper holder which are concentrically disposed through a central portion of the mirror surface plate. Etc. are formed cooperatively by the axial end surfaces and stampers of a plurality of mold members. In a molding die in which the cavity forming surface is formed cooperatively by a plurality of members as described above, a boundary portion of each member is formed. Inevitably, a gap of 10 μm or more is unavoidable. In particular, a gap of 10 to 30 μm is required between the inner and outer peripheral mold members of the ejector sleeve driven in the axial direction. When the resin material enters, annular burrs are likely to occur on the disk molded product, albeit slightly. According to measurements made by the inventor,
Such an annular burr has a maximum height of 20 to 30 μm at a portion corresponding to an area between the ejector sleeve and the stationary sleeve when polycarbonate is used as a molding material. The maximum height was 15 to 25 μm at the portion corresponding to the space between the stamper holders, and the protrusions were generated.

Therefore, even if the shapes and dimensions of the first and second discs alone are within the allowable accuracy, when the two discs are overlapped, the annular burrs formed on each disc abut against each other. As a result, the two discs cannot be superposed with a desired gap, and the gap between the superposed faces of the two discs becomes large or non-uniform. The present inventor has newly obtained the knowledge that problems such as poor thickness and poor thickness will be caused, and thus completed the present invention.

The feature of the present invention relating to a single-sided reading type bonded disc made based on such knowledge is that a stamper is set in one of the molds and each cavity forming surface is formed. The first disk and the second disk, each formed by using a pair of molds formed of a plurality of concentrically arranged members and forming a molding cavity between the mold mating surfaces, are bonded to an adhesive layer. A bonded disc that is superimposed and adhered via a boundary position between the plurality of members forming the cavity forming surface of one molding die, and a plurality of forming the cavity forming surface of the other molding die. The boundary position of the member is set at one of the molding dies by a pair of molding dies which are radially different from each other at least in a facing region within the center hole of the stamper. A first disk formed by setting a stamper, and a second disk formed by setting a blank stamper in the one mold, the stamper transfer surface of the first disk, the second disk This is because the surface opposite to the stamper transfer surface is overlapped and adhered.

[0010] The "information stamper" and the "blank stamper" are both superposed on the surface of one mold and set by a predetermined holding mechanism to constitute a part of the cavity forming surface. The stamper is a thin annular disk-shaped stamper. In particular, the "information stamper" refers to a stamper having irregularities (information) such as pits and pre-grooves to be transferred to a superposed surface of a disc formed on the surface, while a "blanks A `` tamper '' refers to a material that does not require any information to be transferred to a disc.For example, a stamper or the like that has no irregularities on its surface and is mirror-finished is suitable as a blank stamper. Adopted to. The “cavity forming surface” is a pair of molds,
It is a surface forming a disk molding cavity by being matched with each other, and does not include a surface on which a gate, a runner or the like is formed in a disk center hole or the like. Further, the “facing region in the center hole of the stamper” refers to a region of the cavity forming surface located radially inward of the inner peripheral edge of the stamper, and does not include the boundary position of the inner peripheral edge of the stamper. Further, the “stamper transfer surface” refers to a surface formed by the cavity forming surface of the mold on which the stamper is set.

That is, in the bonded disc having the structure according to the present invention, the superposed face of the first disc is formed by the cavity forming face of one of the molds, while the superposed face of the second disc is formed. The surface is formed by the cavity forming surface of the other mold, and the boundary positions of the members on the cavity forming surfaces of the two molds are different from each other, so that the first and second discs are formed. Since the burrs on the overlapping surfaces are shifted from each other in the radial direction of the disk, mutual interference of burrs on the first disk and the second disk which are superposed is avoided.

Therefore, even when burrs are present on the superposed surfaces of the first and second disks, the two disks can be brought sufficiently close to each other while avoiding the mutual interference of the burrs between the two disks. The two disks can be bonded to each other via the adhesive layer having a small thickness, and a defective rate such as a defective bonding or a defective thickness due to the generation of a gap between the two disks can be greatly improved.

Further, in order to solve the above-mentioned problem,
A feature of the present invention relating to a method for manufacturing a single-sided reading type bonded disc is that a stamper is set in one molding die, and each cavity forming surface is constituted by a plurality of members arranged concentrically. Using a pair of molds that form a molding cavity between the mold mating surfaces, separately forming the first disk and the second disk, and overlapping the first disk and the second disk with each other. A method of manufacturing a bonded disc by bonding via an adhesive layer, comprising: (a) a boundary position between a plurality of members forming a cavity forming surface of one molding die and another molding die; A pair of molds in which the boundary positions of the plurality of members forming the cavity forming surface are radially different from each other at least in the facing region within the center hole of the stamper. A step of preparing; (b) a step of setting an information stamper on one of the pair of molds to form a first disc; and (c) a blanking step of forming one of the pair of molds on one of the pair of molds. Setting a tamper to form a second disk, (d) transferring the first disk and the second disk to a stamper transfer surface of the first disk and a stamper transfer surface of the second disk And superposing the surfaces opposite to each other so as to face each other and bonding them together via an adhesive layer.

That is, according to the manufacturing method of the present invention, a pair of molding dies in which the boundary positions of the members on the respective cavity forming surfaces are different from each other are used, and the cavity forming surface of one molding die is used. As a result, the overlapping surface of the first disk is formed, while the cavity forming surface of the other mold forms the overlapping surface of the second disk. Are shifted from each other in the radial direction of the disk.

Therefore, even if burrs are generated on the superposed surfaces of the first and second disks in the step of forming the first and second disks, mutual interference of the burrs on the two disks is prevented in the bonding step. It is possible to make the two disks sufficiently close to each other while avoiding them, and the product defect rate such as defective adhesion or defective thickness due to the generation of a gap between the two disks is greatly improved.

Further, in order to solve the above-mentioned problems, a feature of the present invention relating to a single-sided reading type lamination type disc forming apparatus is that the apparatus is overlapped with each other via an adhesive layer and adhered. (A) a stamper is set in one of the molding dies, and each cavity forming surface is concentrically arranged. Composed of multiple members,
A pair of molding dies forming a molding cavity between the mold mating surfaces; and (b) an overlapping surface side of the first disk with respect to the second disk by being set in one of the pair of molding dies. And (c) an information stamper forming a part of a molding surface of the pair of molding dies, which is set on one of the pair of molding dies so that a surface of the second disk opposite to a surface on which the first disk is superimposed. And a blank stamper which forms a part of the molding surface of the present invention, wherein the information stamper and the blank stamper are selectively set to one of the molding dies.

That is, in the disk forming apparatus having the structure according to the present invention, the boundary positions of the members on the cavity forming surface which cause the generation of burrs are different from each other in each of the forming dies. Then, at the time of molding the first disk, the overlapping surface is formed by the cavity forming surface of one of the molds on which the stamper has been set, while at the time of molding the second disk, the side opposite to the side where the stamper has been set. Since the overlapping surface can be formed by the cavity forming surface of the other molding die, the first disk and the second disk whose burrs are generated on the surfaces to be overlapped with each other are displaced in the disk radial direction. The disk can be advantageously formed.

In the first and second disks formed using such a disk forming apparatus having the structure according to the present invention and having burrs generated at different positions, mutual interference of burrs Because both discs can be brought close enough to adhere while avoiding
The product defect rate such as defective adhesion or defective thickness due to the generation of a gap between the two disks is greatly improved.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, in order to clarify the present invention more specifically, embodiments of the present invention will be described in detail with reference to the drawings.

First, FIG. 1 shows a disk forming die for forming a first disk and a second disk which provide a single-sided reading type bonded disk. This mold has a fixed mold 10 as a pair of molds.
And a movable mold 12, which are not shown,
While the fixed mold 10 is attached to the fixed plate of the mold clamping device, the movable mold 12 is attached to and supported by the movable plate of the mold clamping device, and by moving the movable plate in the approaching / separating direction with respect to the fixed plate, These fixed mold 10 and movable mold 1
The mold 2 is opened and closed. Then, as shown in the drawing, the fixed mold 10 and the movable mold 12 are subjected to mold matching, so that the molding cavity 14 of the first disc or the second disc is formed between the mold matching surfaces. Has become. That is, in the present embodiment, the fixed mold 10 and the movable mold 1 having the structure as shown in FIG.
Using a pair of molding dies, a first disc on which predetermined information has been transferred and a dummy second disc having no information surface are respectively formed, and are formed on the information surface of the first disc. After forming a reflective film and the like, an appropriate adhesive is applied to the superposed surfaces of the two disks and the two disks are superimposed, and the two disks are adhered via an adhesive layer, thereby obtaining
As a result, a single-sided reading type bonded disc such as a VD is formed.

More specifically, a fixed mirror block 16 having a substantially thick annular plate shape is fixedly mounted on the fixed mold 10 via a back plate 18 on the side where the molding cavity 14 is formed. Installed. In addition, a center bush 20 is fixedly disposed so as to penetrate through the center portion of the fixed side mirror block 16 and the back plate 18 in the axial direction, and a center hole of the center bush 20 is provided with a disk center hole. A female cutter sleeve 21 for punching is provided, and a sprue bush 24 is provided in a center hole of the female cutter sleeve 21.

In this embodiment, the cavity forming surface 22 on the fixed mold 10 side is provided with the mirror surface of the fixed mirror block 16 and the center bush 20 and the female bush concentrically arranged at the central portion of the fixed mirror block 16. Cutter sleeve 2
1 are formed in cooperation with each other. Further, in the fixed mold 10 of the present embodiment, the resin material injected from the nozzle of the injection device (not shown) is guided to the molding cavity 14 and filled through the center hole of the sprue bush 24. At the same time, compressed air is supplied to the superposed surface of the female cutter sleeve 21 and the center bush 20 to assist in releasing the molded product when the mold is opened after the molding, and the compressed air is discharged to the cavity forming surface 22. ing.

In the movable mold 12, similarly to the fixed mold 10, a movable mirror block 28 having a substantially thick annular plate shape is provided on the side where the molding cavity 14 is formed via a back plate 30. , Fixedly mounted. Furthermore,
A substantially cylindrical stamper holder 32 having an outer peripheral surface tapered over a predetermined length in the axial direction is inserted through the movable mirror block 28 and the central portion of the back plate 30 in the axial direction, and is not shown. It is fixedly attached by a screw mechanism or the like. A stationary sleeve 34 is inserted through a central hole of the stamper holder 32 and is fixed to the movable mold 12. An ejector for releasing a molded product from the central hole of the stationary sleeve 34 is also provided. The ejector sleeve 38 is guided through the inner peripheral surface of the stationary sleeve 34 by a driving mechanism (not shown) and is reciprocated a predetermined amount in the axial direction. Further, a male cutter sleeve 40 for punching a disk center hole is inserted through the center hole of the ejector sleeve 38 so as to be movable in the axial direction, and the center hole of the male cutter sleeve 40 is A moving sleeve 41 which is reciprocated together with the male cutter sleeve 40 under a driving force.
Is provided in the center hole of the moving sleeve 41, and an ejector pin 42 for releasing the gate portion is released.
Are disposed so as to be able to protrude in the axial direction.

On the movable mirror block 28, a thin annular plate-shaped stamper 44 is mounted, and an inner peripheral edge thereof is formed in an annular stamper holder 45 (FIG. 1) protruding from the outer peripheral edge of the stamper holder 32. 2), while the outer peripheral edge portion is held by an outer peripheral holding ring 46 having a hook-shaped cross-section fixed to the movable mold 12, so that the stamper 44 becomes a mirror surface of the movable mirror block 28. It is designed to be mounted on top.

That is, in the present embodiment, the stamper 44 mounted on the mirror surface of the movable mirror block 28, the stamper holder 32 and the stepper positioned in the center hole of the stamper 44 and arranged concentrically with each other. The axial end surfaces of the shoulder sleeve 34 and the ejector sleeve 38 cooperate to form the cavity forming surface 36 on the movable mold 12 side. Although not explicitly shown in the drawing, compressed air for assisting the release of the molded product is supplied to the superposed surface of the ejector sleeve 38 and the stationary sleeve 34 and discharged to the cavity forming surface 36. I am being squeezed.

As is apparent from this, in the present embodiment, one of the molding dies on which the stamper 44 is set is constituted by the movable mold 12, and the stamper is set by the fixed mold 14. The other mold is not formed.

Here, the stamper 44 and the stamper holder 3 constituting the cavity forming surface 36 of the movable mold 12 are provided.
2. The stationary boundary between the stationary mirror block 16, the center bush 20, and the female part of the stationary sleeve 34 and the ejector sleeve 38, each of which has an annular boundary position extending in the circumferential direction between the members, constitutes the cavity forming surface 22 of the stationary mold. The cutter sleeve 21 is radially shifted by a predetermined amount from an annular boundary position extending in the circumferential direction between the members. That is, as shown in FIG. 2, the diameters of the respective annular boundary positions A, B, and C on the cavity forming surface 36 of the movable mold 12 are φa, φb, and φc. Each of the annular boundary positions on the forming surface 22 is set to be different from the diameter dimension of D and E: φd and φe, whereby the boundary positions of the movable mold 12 are fixed to A, B, and C. Boundary position of mold 10:
D and E are set to be shifted from each other in the radial direction so as not to be opposed to each other in the mold matching direction of the movable mold 12 and the fixed mold 10. In this embodiment, as is apparent from FIG. 2, φc <φe <φb <φa <φd.

When the first disk and the second disk are formed using the dies 10 and 12 having such a structure, the pits to be transferred to the disk are provided separately from the dies 10 and 12 main body. An information stamper 44 (a) having predetermined information such as a groove and a pre-groove formed on the surface thereof, and a blank stamper 44 (b) having a mirror-finished surface and having no information to be transferred formed thereon are prepared. I do. Then, the information stamper 44 (a) is set on the movable side mirror block 28 of the movable mold 12, the fixed mold 10 and the movable mold 12 are mold-matched, and the molding cavity 14 formed between the mold mating surfaces is formed. Is filled with a predetermined resin material to form a first disk 50 (see FIG. 3) on which information of the information stamper 44 (a) is transferred. Apart from the formation of the first disk 50, the blank stamper 44 (b) is placed on the movable mirror block 28 of the movable mold 12.
Is set, the fixed mold 10 and the movable mold 12 are mold-matched, and the molding cavity 14 formed between the mold-matching surfaces is set.
Is filled with a predetermined resin material to form a second disk 52 (see FIG. 3). That is, the molding die of the present embodiment selects and replaces the stamper 44 set on the movable mold 12 to thereby obtain a first disk 50 as an information disk having an information surface on which predetermined information is transferred.
Of the second disk 52 as a dummy disk having no information surface and as a dummy disk having no information surface.

The first disk 50 and the second disk 52 are shown in FIG. 4 after a reflective film is formed on the information surface of the first disk 50 according to a conventional method. As described above, by overlapping and bonding with each other via the adhesive layer 55, the intended bonded disc 56 is obtained.

Here, in the first disk 50,
A surface (information surface) formed by the cavity forming surface 36 on the movable mold 12 side including the information stamper 44 (a) (information surface)
Is the overlapping surface 54 for the second disk 52, while the surface of the second disk 52 formed by the cavity forming surface 22 on the stationary mold 10 side is the overlapping surface for the first disk 50. A mating surface 58 is provided.

That is, in the first disk 50 and the second disk 52, the boundary positions of the members forming the cavity forming surfaces 22, 36 of both the dies 10, 12 are as follows:
Due to the resin material entering the gaps between A, B, C, D and E, annular burrs 60 and 62 extending in the circumferential direction on the disk surface may be generated as shown in FIG. However, the radial positions of the boundary positions D and E on the cavity forming surface 22 on the fixed mold 10 side and the boundary positions A, B and C on the cavity forming surface 36 on the movable mold 12 side are mutually opposite. The annular burr 60 generated on the overlapping surface 54 of the first disk 50 and the annular burr 62 generated on the overlapping surface 58 of the second disk 52 are displaced from each other in the radial direction. The two disks 50, 5
The mutual interference of the annular burrs in 2 is avoided.

In short, the first and second disks 50,
30 on each of the superimposed surfaces 54 and 58
Assuming that annular burrs 60 and 62 having a height of m are generated, if at least one occurrence position of the annular burrs 60 and 62 is the same on the overlapping surfaces 54 and 58, the disks 50 and 52 are overlapped. When combined, both annular burrs 60, 62
Abut against each other and act like a support rod, and both discs 50,
Since it is not possible to bring the adhesive layer 52 sufficiently close, it is extremely difficult to stably obtain the adhesive layer 55 having a target thickness (for example, 40 μm). First and second discs 5 formed in a mold
At positions 0 and 52, the positions at which the annular burrs 60 and 62 are formed on the respective superposed surfaces 54 and 58 are shifted in the radial direction. Even if
By avoiding the mutual interference of the annular burrs 60, 62 between the two disks 50, 52, the first disk 50 and the second disk 52 are brought close to, for example, 40 μm or less, and the desired thickness of the adhesive is bonded. The agent layer 55 can be stably obtained.

Although the embodiments of the present invention have been described in detail above, these are literal examples, and the present invention is not limited to such specific examples.

For example, in the above-described embodiment, the stamper 44 is mounted on the movable mold 12 side. However, the stamper 44 may be mounted on the fixed mold 10 side.

As the structure for attaching the stamper 44 to the mold, a vacuum suction structure or the like may be employed in addition to the pressing structure of the inner peripheral portion of the stamper as illustrated.

Further, the boundary position of the plurality of members forming each cavity forming surface is at least in the center hole of the stamper (in other words, it is exposed to the molding cavity of the stamper surface and forms a part of the cavity forming surface. In the opposing region at the portion located radially inward from the innermost peripheral portion of the portion), it is sufficient if they are different from each other in the radial direction.
For example, when the inner peripheral portion of the stamper 44 is pressed and held by the stamper holder 32 as in the above-described embodiment, the burr generated due to the resin material entering the gap between the inner peripheral edges of the stamper 44 is generated. Because there is almost no problem, the boundary position of the member of the cavity forming surface in the other mold may be opposed to the boundary position between the stamper 44 and the stamper holder 32. However, the effects of the present invention can be effectively achieved.

The plurality of members forming the cavity forming surface are appropriately designed in accordance with the structure of the molding die and the like, and are not limited to those in the above-described embodiment.

In addition, although not enumerated one by one, the present invention
Based on the knowledge of those skilled in the art, the present invention can be implemented in a form in which various changes, modifications, improvements, and the like are made.
It goes without saying that all such embodiments are included within the scope of the present invention, without departing from the spirit of the present invention.

[0039]

As is apparent from the above description, according to the present invention, the burrs on the first disk and the second disk which are superimposed on each other are shifted from each other, so that the two disks are superimposed. Since the mutual interference of burrs between the surfaces is avoided, such as a disk adhesion defect and a thickness dimension defect caused by the mutual interference of burrs.
Conventional problems can be solved, and the defective product rate of the bonded disc can be greatly improved.

[Brief description of the drawings]

FIG. 1 is an explanatory longitudinal sectional view showing a specific example of a molding die used for carrying out the method of the present invention.

FIG. 2 is an explanatory diagram showing a main part in FIG. 1 in an enlarged manner.

FIG. 3 is an explanatory cross-sectional view showing, on an enlarged scale, respective main parts of a first disk and a second disk separately formed by using the forming die shown in FIG. 1;

FIG. 4 is an enlarged cross-sectional view of a main part showing a specific example of a bonded disc having a structure according to the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 fixed mold 12 movable mold 14 disk molding cavity 16 fixed mirror block 20 center bush 21 female cutter sleeve 22 cavity forming surface (fixed mold side) 28 movable mirror block 32 stamper holder 34 stationary sleeve 36 cavity formation Surface (movable mold side) 38 Ejector sleeve 44 Stamper 50 First disk 52 Second disk 54, 58 Lamination surface 55 Adhesive layer 56 Laminated disk 60, 62 Burr

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G11B 7/24 G11B 7/26

Claims (3)

(57) [Claims] 1. A pair of molds, each having a stamper set on one mold and each cavity forming surface being formed by a plurality of members arranged concentrically, and forming a molding cavity between the mold mating surfaces. Using the first disk and the second disk respectively formed, via an adhesive layer,
A bonded disc that is superimposed and bonded, wherein a boundary position of the plurality of members forming a cavity forming surface of the one mold and the plurality of members forming a cavity forming surface of the other mold are provided. The boundary position of the first stamper is formed by setting an information stamper in one of the stampers by a pair of stampers radially different from each other in at least an opposing region in the center hole of the stamper. A disk, and the second disk formed by setting a blank stamper in the one mold, the stamper transfer surface of the first disk, the opposite side of the stamper transfer surface of the second disk A laminated disc characterized in that surfaces are superimposed and adhered. 2. A pair of molds, each having a stamper set in one mold and each cavity forming surface being constituted by a plurality of members arranged concentrically, and forming a molding cavity between the mold mating surfaces. Using, the first disk and the second disk are separately formed, and the first disk and the second disk are superimposed on each other and adhered through an adhesive layer, thereby forming a bonded disk. Wherein the boundary position of the plurality of members forming the cavity forming surface of one mold, and the boundary position of the plurality of members forming the cavity forming surface of the other mold, at least the A step of preparing the pair of dies which are radially different from each other in a facing region within the center hole of the stamper; and forming the one of the pair of dies. Setting an information stamper to form the first disc; setting a blank stamper to the one of the pair of molds to form the second disc; The first disk and the second disk are overlapped so that the stamper transfer surface of the first disk and the surface opposite to the stamper transfer surface of the second disk face each other, and the adhesive Adhering through a layer. 3. An apparatus for forming a first disk and a second disk which are laminated and bonded to each other via an adhesive layer to provide a bonded disk, wherein one of the molding dies is provided. A stamper is set, each cavity forming surface is constituted by a plurality of members arranged concentrically, a pair of molding dies forming a molding cavity between the mold mating surfaces, and the one of the pair of molding dies By being set in a molding die, an information stamper that constitutes a part of a molding surface on the side of the first disk that overlaps the second disk, and the one molding die in the pair of molding dies. By being set, a bra that constitutes a part of the molding surface of the second disk on the side opposite to the superimposed surface on the first disk And a blank stamper, wherein the information stamper and the blank stamper are selectively set with respect to the one mold.