JPS62285248A - Optical information recording disk medium having hollow structure and its manufacture - Google Patents

Abstract

PURPOSE:To prevent the stain of the end face of a disk due to an adhesives and the reduction in the adhering capability of the adhesives and of the function as a spacer by providing a section to sectioning a ring at least at the position of the adhesives applied in a ring form. CONSTITUTION:Adhesives 3a, 3b are applied in the ring form at least at one of two bases 1a, 1b along the inner and outer circumferential ridges, both the bases 1a, 1b are overlapped and adhered to manufacture a hollow optical information recording disk medium. In such manufacture, after a section 5 separating the ring at least at one part of the adhesives 3a, 3b applied in a ring form, both the bases 1a, 1b are overlapped. Since the air in the inner space is emitted externally from the section, the air pressure is not increased and the ring shape of the adhesives is hardly disturbed. Thus, the adhesives do not give the stain to the ends of the optical information recording disk medium and the adhesive operation of the adhesives and the function as a spacer are not deteriorated.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a hollow structure for optically recording and reproducing information.
The present invention relates to an optical information recording disk medium with a so-called air sandwich structure and a method of manufacturing the same.

[Conventional technology]

FIG. 2 shows a schematic cross-sectional view of an optical information recording disk medium having a hollow structure. La and lb are substrates having a central hole that is transparent to laser light, and are made of glass, plastic, or the like. 2a and 2b are recording layers formed on the substrate, which undergo shape changes, phase changes, magneto-optical changes,
Consists of substances that decompose. In some cases, auxiliary layers such as very thin reflective layers and protective layers are laminated above and below the recording layer.

Two substrates la and l on which the recording layer 2a or 2b is formed
b is made by an adhesive 3 which also serves as a spacer and is applied in a ring shape near the inner and outer edges.
They are bonded so that the internal space 4 is sandwiched therebetween. Incidentally, an optical information recording disk medium having an air-sun 7-chi structure in which an information recording layer is provided only on one substrate is also well known.

The internal space is used not only for the purpose of protecting the recording layer when using a disk medium, but also for the purpose of preventing the formation of recording pits. Since there is no need for contact, the thermal energy from the laser beam is difficult to diffuse, improving recording sensitivity. Furthermore, in the case where pits are formed in the recording layer due to deformation, evaporation, decomposition, etc. caused by laser light, the formation of pits is easy because the surface of the recording layer is easily transformed.

[Problem that the invention seeks to solve]

To manufacture an optical information recording disk medium with an air sandwich structure as described above, adhesive is applied in a ring shape along the inner and outer edges of at least one substrate, and then the two substrates are stacked. A matching method is being used.

In this method, the thickness of the adhesive applied to the boards is inevitably thicker than the final gap between the two boards when completed, and after the boards are stacked together, pressure is applied to the boards to spread the adhesive between each board. An optical information recording disk medium having a spacing between substrates that is thinner than the initial coating thickness of the adhesive is produced by adapting it to the substrate. This situation is shown in Figures 3 (a), (b), and (c), which schematically show cross-sectional views near the outer periphery of the board. (a) shows the state in which adhesive is applied to one board. show,
(b) shows when another board is placed on the adhesive.
It shows the state at the moment when the substrate and the adhesive surface come into contact, (C
), pressure is applied to the substrates and the adhesive adapts to each substrate.
This figure shows the completed state in which the distance between the two substrates is narrower than originally.

When manufacturing such an optical information recording disk medium.

Conventionally, adhesive was applied in a ring shape along the entire inner and outer edges of the board, so at the point shown in Figure 2, the ring-shaped adhesive near the inner and outer edges and the two boards were applied. The trapped air undergoes compression by the time the two substrates reach their final spacing as shown in FIG. 2C. As a result, the air pushes out the ring-shaped adhesive, crushes the adhesive layer, and escapes to the outside, which disturbs the ring shape of the adhesive, stains the edge of the disk medium, and prevents the adhesive from acting as a spacer. leading to a decline in the role of Also,
Depending on the viscosity of the adhesive, the ring shape may not be distorted, but in this case, if the pressure is released after the condition shown in Figure 3C is reached, the board spacing and parallelism may become inaccurate due to internal air pressure. I get pushed back.

The purpose of the present invention is to solve this drawback, and to prevent the ring-shaped adhesive applied near the inner and outer edges of a hollow optical information recording disk medium from being disturbed, and to improve the distance between two substrates. The object of the present invention is to manufacture an optical information recording disk medium with accurate parallelism and accuracy.

[Means for Solving the Problems] The present invention, which can achieve the above object, comprises two disk-shaped substrates each having a central hole, each of which is provided with a recording layer on which information is optically recorded. On the other hand, the little seven
An adhesive is applied in a ring shape along each of the inner peripheral edge and the outer peripheral edge, and these two substrates are overlapped, and the recording layer is placed inside and an internal space is formed between the two substrates by the adhesive. When producing an optical information recording disk medium with a hollow structure by bonding the substrates together, the adhesive applied in a ring shape is provided with a break that separates the ring, and then the two substrates are stacked together. It is characterized by

The state of the substrate and the adhesive applied thereto after the operations characteristic of the method of the invention have been carried out is shown in the perspective view of FIG. A state in which a break 5 is provided at one location of the adhesives 3a and 3b applied in a ring shape along each of the peripheries is shown. As a method for applying the adhesive in such a state, a known technique such as screen printing, dispenser printing, offset printing, etc. may be used to provide a break during or after application of the adhesive.

In the method of the present invention, when transitioning from the state shown in FIG. 3 S to the state shown in FIG. Therefore, the adhesive does not stain the edges of the optical information recording disk medium, and the adhesive action and spacer function of the adhesive does not deteriorate. The state shown in Figure 3C is maintained as it is.

It is sufficient to provide the break at at least one location for degassing, but considering the weight balance during rotation of the optical information recording disk, it is effective to provide the break on multiple sides symmetrically with respect to the center hole. Considering the same points, it is better to provide it near the inner periphery than near the outer periphery.It is preferable to minimize the size of the break. This is because flatness, breakage resistance, etc. can be maintained for a long period of time by firmly adhering at certain points. If necessary, you can overlap the two substrates and close the gap after the adhesive has hardened. To determine the final spacing between the two substrates, place a part of the substrate approximately equal to the spacing. Various methods can be considered, such as a method of providing a projection or a method of using a ring-shaped spacer member. However, a method in which particles having a diameter approximately equal to the spacing is mixed into the adhesive is particularly effective from the viewpoint of cost and productivity.

[Example] Example 1 Outer diameter: 200 mm, thickness: 35 mm diameter center hole!
, 2 arm disc-shaped transparent polycarbonate substrates
One was created. A recording layer was formed by applying a polymethine dye having a light absorption peak around 830 μs to a thickness of 100 OA using a spinner only on one side.

On the other hand, the particle size is 0.
Glass beads of 5 to 0.59 mm were added and mixed in an amount of 10% by weight. The substrate on which the recording layer was not formed was rotated, and the adhesive was discharged from a dispenser and applied in a ring shape near the inner and outer edges of the substrate along each edge.

The width of each adhesive was about 21 mm, the height was about 1 mm, and the cross-sectional shape was approximately semicircular. As shown in Figure 1, the adhesive applied near the outer edge of the board has a width of approximately 3mm in one spot.
I provided a break in the adhesive. The substrate on which the above-mentioned recording layer was formed was stacked on this substrate with the recording layer inside. At that time, the positions were adjusted so that the center holes were aligned. When a pressure of 20 kg was applied so that the force was applied uniformly to the entire surface of the substrate, the final spacing between the substrates was approximately 0. It becomes flimm, and the adhesive.

A neat ring shape with a width of about 3 cm was formed along the inner and outer edges of the substrate, and the edge of the disk medium was not contaminated at all.

Comparative Example 1 An optical information recording disk was produced in the same manner as in Example 1 except that the adhesive applied in a ring shape was not provided with any breaks. Since the adhesive was spread out by the air pressure within the internal space, meandering was observed, and the adhesive gushed out from one location on the outer periphery, staining the outer periphery end surface. In addition, because the substrates were pushed back by the pressure of the trapped internal air, the spacing between the substrates after being cured at room temperature was approximately 0.8 degrees near the outer periphery, but approximately 0.8 degrees near the inner periphery.
It became mm.

〔Effect of the invention〕

According to the present invention described in detail above, when two substrates are bonded together with an adhesive to form a hollow optical information recording disk medium, the adhesive is spread by the air in the internal space and the shape of the optical information recording disk medium is expanded. Therefore, the adhesive does not stain the edge surface of the disk, the adhesive action and function as a spacer do not deteriorate, and the air pressure in the internal space does not increase, so the board spacing and parallelism are accurate. is formed.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a state in which adhesive is applied to a substrate in a ring shape with some breaks in the method of the present invention; FIG. 2 is a schematic cross-sectional view of an optical information recording disk medium having a hollow structure; FIG. 3 is a schematic cross-sectional view showing the process of applying an adhesive to a substrate and then overlapping another substrate to bond the two substrates together. la, lb...board, 2a, 2b...
...recording layer. 3.3a, 3b...Adhesive, 4...
...Inner space, 5......Temporary.

Claims (1)

[Scope of Claims] 1) At least one of two disc-shaped substrates having a central hole, on at least one of which is provided with a recording layer on which information is optically recorded, an inner peripheral edge and an outer peripheral edge thereof. An adhesive is applied in a ring shape along each of the two substrates, and these two substrates are overlapped, and the adhesive is used to bond the two substrates so that the recording layer is on the inside and an internal space is formed between the two substrates. What is claimed is: 1. An optical information recording disk medium having a hollow structure, characterized in that an adhesive applied in a ring shape is provided with a break at at least one place to separate the ring. 2) The optical information recording disk medium according to claim 1, wherein the adhesive contains granular material having a diameter approximately equal to the height of the formed internal space. 3) At least one of two disk-shaped substrates having a central hole, each of which is provided with a recording layer on which information is optically recorded, along each of its inner and outer edges. , apply an adhesive in a ring shape, overlap these two substrates, and bond them together with the adhesive so that the recording layer is on the inside and an internal space is formed between the two substrates to create optical information in a hollow structure. A method for manufacturing an optical information recording disk medium, characterized in that the adhesive applied in a ring shape is provided with a break that separates the ring at at least one location, and then both substrates are superimposed. Method. 4) The method for manufacturing an optical information recording disk medium according to claim 3, wherein the gap is closed after the adhesive is cured.