JPH10199055A - Pressing welding device and method for producing optical information recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stick two discoid substrates to each other in parallel with a high precision even though there exists dispersion in the thickness of the peripheral section of the substrates by employing at least one discoid pressing plate having a press effective diameter that is smaller than the diameter of a discoid substrate. SOLUTION: The protective layer of two substrates made of three laminated layers is coated with an adhesive material. The two substrates are laminated while putting these layers inside. Then, both discoid substrates 81a and 81b are adjusted so that their centers come to a prescribed position and are placed on the bottom side of a pair of discoid pressing plates 11a and 11b. Then, a pressure is applied to the plates 11a and 11b and the substrates are stuck together. Since the pressing plates have smaller effective diameters than the diameters of the substrates, the entire surfaces of the plates are adhered to the surfaces of the substrates even though there exist burrs on the outer peripheral sections of the substrates, the pressure applied to the pressing plates is uniformly applied to the substrates and the two substrates are stuck together in parallel with a high precision.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure bonding apparatus used for producing an optical information recording medium having a sandwich structure in which two disc-shaped substrates or a disc-shaped substrate and a disc-shaped protective substrate are bonded to each other. And a crimping method. In particular, the present invention relates to an improvement of a pressure plate provided in a pressure bonding device used when bonding these substrates.

[0002]

2. Description of the Related Art Recently, a DVD (Digital Video Disk) capable of achieving a large recording capacity has been actively studied as an optical information recording medium from which information can be read or written using a laser beam. DVDs are read-only (DVD-ROM) or write-once DVs depending on the application.
D (DVD-R) or rewritable DVD (DVD-R
AM) has been proposed. These optical information recording media are
Two disk-shaped substrates each provided with a layer from which information can be read or written by laser light, or a disk-shaped substrate provided with a layer from which information can be read or written by laser light, and a disk having the same shape as the substrate Each of the substrates has a sandwich type structure in which the respective substrates are overlapped with each other so that these layers are on the inner side, and both substrates are bonded together via an adhesive layer. For example, taking a write-once DVD as an example, this optical information recording medium 80 is formed with a guide groove (pre-group) for tracking, as shown in FIG. Disc-shaped substrates 81a and 81b having a recording layer 86b, dye recording layers (recording layers) 82a and 82b formed on the disc-shaped substrates, and reflective layers 83a and 83b and a protective layer 84a formed thereon.
In this structure, two discs 84b in order are bonded together with an adhesive layer 85 with the respective recording layers facing inward. Incidentally, these optical information recording media, for example,
"Nikkei Electronics" (Special Issue: Optical Disk, 199
5 years, no. 630) and “Nikkei New Media” (separate volume [DVD], published in 1995).

[0003]

SUMMARY OF THE INVENTION The present inventor has studied a crimping apparatus conventionally used when manufacturing an optical information recording medium having a sandwich structure as described above. As a crimping device, for example, a device 70 provided with two disk-shaped pressing plates 71a and 71b as shown in FIG. 7 is generally used. An optical information recording medium having a sandwich structure is manufactured by the following steps using such a pressure bonding apparatus. The manufacturing method of the write-once type DVD described above will be briefly described. First, a recording layer is formed on one side of a disc-shaped substrate using a spin coater or the like, and a reflection layer is provided on the recording layer by masking or the like by vapor deposition or the like. Further, a protective layer made of a curable resin is provided on the reflective layer. Thus, two disk-shaped substrates having three layers stacked are prepared. Next, an adhesive is applied on the protective layer of one or both substrates, and these substrates are overlapped such that each layer is on the inside. After the two substrates are overlapped, the two substrates are sandwiched between the two pressing plates 71a and 71b of the crimping device shown in FIG. 7 and pressed from outside the substrates, whereby the two substrates are bonded in parallel. An optical information recording medium having a sandwich type structure can be manufactured.
The two pressing plates provided in the pressure bonding apparatus are generally formed with an outer diameter larger than that of the disk-shaped substrate as shown in the drawing so that a uniform pressing operation can be performed over the entire surface of the substrate.

[0004] The disk-shaped substrate has a donut shape having a circular hole at the center thereof, and is usually formed of a resin material such as polycarbonate. For this reason, projections such as burrs are likely to occur at the peripheral portion of the substrate, especially at the outer peripheral portion, and the substrate after molding has a problem that the thickness tends to be uneven at the peripheral portion. According to the study of the present inventor, when a substrate having such a thickness variation at the peripheral portion is used, the pressing plate does not completely adhere to the substrate surface when pressing from the outside of the substrate. It has been found that it is difficult to apply pressure uniformly over the entire surface, and as a result, it is difficult to bond two substrates in parallel with high accuracy. In such an optical information recording medium manufactured in a state where the parallelism of the two substrates is not sufficient, for example, a laser beam at the time of reading cannot accurately scan a predetermined track, and thus is likely to cause a decrease in output. . Although a process for removing burrs can be provided after molding the substrate, it is not a preferable method from the viewpoint of productivity because the number of manufacturing steps increases.

An object of the present invention is to provide a crimping apparatus and a method for crimping two disc-shaped substrates which are suitably used for manufacturing an optical information recording medium having a sandwich structure. In particular, an object of the present invention is to provide a crimping apparatus and a crimping method capable of bonding two disc-shaped substrates in parallel with high accuracy even if there are protrusions such as burrs on a peripheral portion of the substrate. It is.

[0006]

According to the study of the present inventor, the use of at least one disc-shaped pressing plate having an effective pressing diameter smaller than the diameter of the disc-shaped substrate allows the peripheral edge of the substrate to have a reduced thickness. It has been found that even if there is a variation, two disc-shaped substrates can be bonded in parallel with high accuracy, thereby making it possible to manufacture an optical information recording medium without causing a decrease in performance such as a decrease in output. The invention has been completed. That is, by using a pressure plate having a pressure effective diameter smaller than the diameter of the disc-shaped substrate, when the substrate is pressed by the pressure plate, there is a portion having an uneven thickness at the outer peripheral portion of the substrate. The pressure plate is placed so that it contacts the surface of the substrate only in areas where the thickness of the substrate is uniform, so the pressure is applied evenly over the entire surface of the substrate, enabling the two substrates to be bonded in parallel with high precision. Become. In this specification, the effective pressing diameter means the diameter of the area of the pressing plate that can be brought into close contact with the substrate surface when the disk-shaped substrate is pressed by the disk-shaped pressing plate.

According to the present invention, there are provided two disk-shaped substrates each provided with a layer from which information can be read or written by a laser beam, or a disk-shaped substrate provided with a layer from which information can be read or written by a laser beam. A disk-shaped protective substrate having the same shape as the substrate, the substrates are overlapped with each other such that these layers are on the inside, and pressure is applied from the outside of each substrate,
There is provided a pressure bonding apparatus for manufacturing an optical information recording medium, comprising at least one disk-shaped pressing plate having an effective pressing diameter smaller than the diameter of the disk-shaped substrate for bonding the substrates together via an adhesive layer.

The present invention is also directed to two disk-shaped substrates each provided with a layer from which information can be read or written by laser light, or a disk-shaped substrate provided with a layer from which information can be read or written by laser light. And a disk-shaped protective substrate having the same shape as the substrate, and the substrates are overlapped with each other such that these layers are on the inside. At least one of the substrates having an effective pressing diameter smaller than the diameter of the substrate from the outside of each substrate. There is also a pressure bonding method for manufacturing an optical information recording medium in which the substrates are bonded to each other via an adhesive layer by pressing with two disk-shaped pressing plates.

The preferred embodiments of the present invention are as follows. (1) The effective pressing diameter of the pressing plate is 90% or more of the diameter of the substrate.
99% (more preferably, 92% to 98%, especially 95%
% To 98%). (2) Both the disk-shaped substrate and the disk-shaped pressing plate are donut-shaped having a circular hole at their respective centers, and the inner diameter of the pressing plate is larger than the inner diameter of the substrate. (3) In the above (2), the diameter of the circular hole of the pressure plate is 1.01 to 1.1 times (more preferably, 1.02 to 1.08 times) the diameter of the circular hole of the substrate. is there.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A crimping apparatus for manufacturing an optical information recording medium (hereinafter, may be simply referred to as a crimping apparatus) and a crimping method according to the present invention will be described with reference to the accompanying drawings. FIG.
FIG. 1 is a schematic cross-sectional view of a preferred example of a pressure bonding apparatus for manufacturing an optical information recording medium according to the present invention. In the following figures, the write-once type DVD described above as an optical information recording medium is shown sandwiched between two pressure plates of a pressure bonding apparatus. As shown in FIG. 1, the crimping apparatus 10 includes two upper and lower disc-shaped pressure plates 11a and 11b. The pressure plates are used as disk-shaped substrates 81a and 81, which constitute the optical information recording medium 80, respectively.
It is formed with a pressurized effective diameter smaller than the diameter of 1b. The effective diameter of the pressure plate is 90% to 9% of the diameter of the substrate.
9% (more preferably 92% to 98%, particularly 95% to
98%). The pressure plate having the pressure effective diameter set in such a range is not affected by burrs generated on the outer peripheral portion of the substrate.

FIG. 2 is a schematic sectional view of another preferred example of the crimping device. As shown in FIG.
The pressurizing plates 21a and 21b provided in the “0” are provided with concave grooves 22a and 22b. The concave groove is formed on the surface of the pressure plate corresponding to the outer peripheral portion of the substrate with the substrate sandwiched between the pressure plates. The surface surrounded by the effective pressurized diameter corresponds to the area formed by the inner peripheral edge of the concave groove. The effective pressurizing diameter in this case can also be set in the same range as described above. The shape of the concave groove is not particularly limited. For example, as shown in FIG. 2, the cross-sectional shape may be a square shape, or, as shown in FIG.
Various shapes such as a triangular shape, a pentagonal shape, a semicircular shape, an elliptical shape, and a trapezoidal shape can be taken. The depth of the concave groove is adjusted by the height of the projection of the burr generated on the periphery of the substrate,
Usually, it is in the range of 0.5% to 20% of the thickness of the pressure plate. In addition, the edge of the concave groove (for example, in FIG. 2, 23a,
The corner portion 23b) is preferably chamfered in a round shape. The radius of the radius is 0.05-10
mm (more preferably, 0.2 to 2 mm).

FIGS. 4 (a) and 4 (b) correspond to the peripheral edges of circular holes 86a and 86b provided at the center of the substrate in the pressing plate of the crimping apparatus shown in FIGS. 1 and 2, respectively. Grooves 14a, 14b, 2
It is a partial cross section schematic diagram of the pressure plate provided with 4a, 24b.
By providing a concave groove on the surface of the pressure plate corresponding to the peripheral portion of the circular hole of the substrate, the influence of projections due to burrs generated at the peripheral portion of the circular hole is also avoided, so that the pressure plate can further affect the surface of the substrate. High adhesion can be realized. The concave groove can be provided in various shapes as described above. Also, the depth of the concave groove can be set in the above range. Further, in the concave groove provided inside the pressure plate, it is preferable that the edge of the groove is chamfered in a round shape as described above.

FIG. 5 is a schematic sectional view of another preferred example of the crimping device. The crimping device 50 shown in FIG. 5 is provided with a donut-shaped pressure plate having a shape in which circular holes 55a and 55b are provided at the centers of the pressure plates 51a and 51b. The diameter of the circular holes 55a and 55b provided in the pressure plate is set larger than the diameter of the circular holes 86a and 86b of the substrate. For this reason, the influence of the unevenness of the thickness of the substrate due to the burrs generated at the peripheral portion of the circular hole can be avoided by the circular hole provided in the pressing plate. Therefore, at the time of pressurization, a portion with high uniformity of the thickness of the substrate other than the inner and outer peripheral portions of the substrate,
In other words, the pressure is applied by the pressure plate in a state of being in contact with only the donut-shaped surface, so that the pressure is evenly applied to the substrate. The diameter of the circular hole of the pressing plate may be set to be in a range of 1.01 to 1.1 times (more preferably, 1.02 to 1.08 times) the diameter of the circular hole of the substrate. preferable. Further, it is preferable that the periphery of the circular hole is chamfered as described above. The pressing device shown in FIG. 5 is an example in which the pressing plate of the pressing device shown in FIG. 1 is provided with a circular hole at the center to form a donut-shaped pressing plate, but is shown in FIG. By providing a circular hole at the center of the pressing plate of the crimping device, a donut-shaped pressing plate can be obtained.

In the pressure bonding apparatus according to the present invention, as described above, both the two pressing plates are designed so that the effective pressing diameter of the two pressing plates is smaller than the diameter of the disc-shaped substrate. Although it is preferable, the effective pressing diameter of only one of the pressing plates can be smaller than the diameter of the disc-shaped substrate. Further, the pressure bonding apparatus according to the present invention is characterized by the shape of the pressure plate as described above, and other requirements (for example, the material and thickness of the pressure plate) are not particularly limited. Therefore, other requirements can be configured in the same manner as the conventional one. For example, as a material of the pressing plate, a material such as stainless steel or glass is usually used.

Next, a brief description will be given of a pressure bonding method for manufacturing the optical information recording medium according to the present invention using the above-described pressure bonding apparatus. The pressure bonding method of the present invention is advantageously used in the final step of bonding two disc-shaped substrates when manufacturing an optical information recording medium having a so-called sandwich structure. An optical information recording medium having a sandwich structure is a read-only DVD-R as described above.
OM, write-once DVD-R, and rewritable DVD-RAM are included. Hereinafter, a write-once DVD-R will be described as an example.

FIG. 6 is a diagram schematically showing a state in which two disk-shaped substrates are overlapped and pressed by using the pressing device of FIG. First, two disc-shaped substrates in an overlapping state are prepared. The disc-shaped substrates 81a and 81b are molded with resin in the same manner as in the related art, and burrs 87a and 87b are formed on the outer peripheral portions as shown in the figure. On one surface of the disc-shaped substrate, a recording layer, a reflective layer, and a protective layer are sequentially formed in a laminated state according to a conventional method. Two substrates having such three layers stacked are prepared. Then, an adhesive is applied on the protective layer of one or both substrates, and the two substrates are overlapped such that these layers are on the inside. Next, the two substrates 81a, 8
The lower pressing plate 11a of the upper and lower two pressing plates 11a and 11b while adjusting the center of the pressing plate 11b so that the center thereof is at a predetermined position.
Place on. Then, pressure is applied to both pressurizing plates to bond the substrates together. Since the pressing plate according to the present invention has an effective pressing diameter smaller than the diameter of the substrate, even if there is a burr on the outer peripheral edge of the substrate as shown in the figure, the pressing plate is entirely covered on the surface of the substrate. It can be in close contact. Therefore,
The pressure applied to the pressing plate is uniformly applied to the substrates, and the two substrates can be bonded in parallel with high accuracy. The above optical information recording medium is an example manufactured using a substrate having a structure in which a recording layer, a reflective layer, and a protective layer are sequentially provided on both of two substrates. Similarly, when a substrate provided with these layers is used and the other substrate is configured as a disc-shaped protective substrate, it is also possible to bond two substrates in parallel with high accuracy.

[0017]

According to the present invention, by using the pressure bonding apparatus provided with the pressing plate according to the present invention, even when a disk-shaped substrate having projections such as burrs on the peripheral edge is used, two substrates can be paralleled with high accuracy. It is possible to attach. Therefore, a higher performance optical information recording medium can be manufactured.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a preferred example of a pressure bonding apparatus for producing an optical information recording medium according to the present invention.

FIG. 2 is a schematic cross-sectional view of another preferred example of a pressure bonding apparatus for producing an optical information recording medium according to the present invention.

FIG. 3 is a schematic diagram showing a cross-sectional shape of a concave groove.

FIG. 4 (a) shows a pressing plate of the pressing device shown in FIG. 1, in which a concave groove is provided on a surface of the pressing plate corresponding to a peripheral portion of a circular hole provided at the center of the substrate. It is a partial section schematic diagram of a pressure plate. (B) is a partial cross section of the pressing plate of the pressing device shown in FIG. 2 in which a concave groove is provided on the surface of the pressing plate corresponding to the peripheral portion of a circular hole provided at the center of the substrate. It is a schematic diagram.

FIG. 5 is a schematic cross-sectional view of another preferred example of a pressure bonding apparatus for manufacturing an optical information recording medium according to the present invention.

FIG. 6 is a diagram schematically showing a state in which two disk-shaped substrates are pressed by using the pressing device of FIG. 1;

FIG. 7 is a schematic sectional view of an example of a conventional pressure bonding apparatus for manufacturing an optical information recording medium.

FIG. 8 is a schematic partial sectional view of a conventional optical information recording medium.

[Explanation of symbols]

10, 20, 50, 70 Crimping device for manufacturing optical information recording medium 11a, 11b, 21a, 21b, 51a, 51b, 7
1a, 71b Disc-shaped pressure plate 14a, 14b, 22a, 22b, 24a, 24b Concave groove 55a, 55b Disc-shaped pressure plate circular hole 80 Optical information recording medium 81a, 81b Disc-shaped substrate 82a, 82b Recording layer 83a, 83b Reflective layer 84a, 84b Protective layer 85 Adhesive layer 86a, 86b Circular hole of disc-shaped substrate

Claims (4)

[Claims] 1. A disc-shaped substrate provided with a layer on which information can be read or written by laser light, or a disc-shaped substrate provided with a layer on which information can be read or written by laser light, and the substrate A disk-shaped protective substrate having the same shape as the above, the substrates are overlapped such that these layers are on the inside, and pressure is applied from the outside of each substrate, and the substrates are bonded to each other via an adhesive layer. A pressure bonding apparatus for producing an optical information recording medium, comprising at least one disk-shaped pressure plate having an effective pressure diameter smaller than the diameter of the disk-shaped substrate. 2. The pressure bonding apparatus according to claim 1, wherein the effective pressing diameter of the pressing plate is 90% to 98% of the diameter of the substrate. 3. Both the disc-shaped substrate and the disc-shaped pressure plate are
The crimping device according to claim 1, wherein the pressure plate has a donut shape having a circular hole at the center thereof, and a diameter of the circular hole of the pressing plate is larger than a diameter of the circular hole of the substrate. 4. A disc-shaped substrate provided with a layer on which information can be read or written by laser light, or a disc-shaped substrate provided with a layer on which information can be read or written by laser light, and the substrate And a disk-shaped protective substrate having the same shape as the above, and the substrates are overlapped with each other such that these layers are on the inner side, and at least one disk-shaped substrate having a pressurized effective diameter smaller than the diameter of the substrate from the outside of each substrate. A pressure bonding method for manufacturing an optical information recording medium in which the substrates are bonded to each other via an adhesive layer by pressing with a pressing plate.