JPS62285249A - Optical information recording disk having hollow structure and its production - Google Patents

Abstract

PURPOSE:To prevent the contamination at the end face of a disk by an adhesive agent coated to an annular shape and the degradation in function as a spacer by embedding a hollow pipe into at least one point of the adhesive agent so as to cross the ring. CONSTITUTION:The hollow pipe 5 is embedded into at least one point of the adhesive agent 3 coated to the annular shape so as to cross the ring and thereafter two substrates 1a, 1b are superposed at the time of producing the optical information recording disk medium having hollow structure by coating the adhesive agent 3 to at least one of the substrates 1a, 1b along the respective inside and outside peripheral edges thereof to the annular shape and superposing and sticking the two substrates. Since the air in the internal space is thereby released from the pipe to the outside, the increase of the air pressure is obviated and the annular shape of the adhesive agent is hardly disturbed. The contamination at the end of the optical information recording disk medium by the adhesive agent is thereby obviated and the degradation in the adhesive effect of the adhesive agent and the function as the spacer is prevented.

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]

A schematic cross-sectional view of a hollow optical information recording disk medium is shown in FIG. 4, where la and lb are substrates having a central hole that is transparent to laser light, m 2 a made of glass, plastic, etc. 2b is a recording layer formed on a substrate, and is made of a substance that undergoes shape change, phase change, magneto-optical change, decomposition, etc. by laser light. 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. Note that optical information recording disk media having an air sandwich structure in which an information recording layer is provided only on one substrate are also well known.

The internal space is not only used for the purpose of protecting the recording layer when using a disk medium, but also has an important meaning for the formation of recording pits.In other words, it is necessary to prevent one side of the recording layer from coming into contact with liquids or solids with relatively high thermal conductivity. This makes it difficult for the thermal energy from the laser beam 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]

In order to manufacture an optical information recording disk medium having an air sandwich structure as described above, at least one of the substrates is
A method is used in which adhesive is applied in a ring shape along the inner and outer peripheries, and then the two substrates are stacked. 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 FIGS. 5(a), (b), and (c), which schematically show cross-sectional views near the outer peripheral edge of the substrate.
a) shows the state in which adhesive is applied to one board, and (b)
) shows the state at the moment when the surface of the adhesive contacts the substrate when another substrate is placed on top of the adhesive, and (C) shows the state at the moment when pressure is applied to the substrate and the adhesive blends into each substrate. This 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 as shown in Figure 6, so at the time shown in Figure 5, the ring-shaped adhesive near the inner and outer edges and two The air trapped by the two substrates is compressed by the time the two substrates reach their final spacing as shown in FIG. 5C. As a result, the air pushes out the ring-shaped adhesive, penetrates the adhesive layer, and escapes to the outside, which disturbs the ring shape of the adhesive and stains the edges of the disk medium.
This leads to a decrease in the adhesive action of the adhesive and its role as a spacer.

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 reaching the state shown in Figure 3C, the board spacing and parallelism may be inaccurate due to internal air pressure. being pushed back into the situation.

The purpose of the present invention is to solve this drawback, and to solve the problem without disturbing the shape of the ring-shaped adhesive applied near the inner and outer edges of a hollow optical information recording disk medium.
The objective is to manufacture an optical information recording disk medium with accurate substrate spacing and parallelism.

[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. to at least one of the
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 manufacturing an optical information recording disk medium with a hollow structure by bonding the substrates together, a hollow pipe is buried in at least one place in the adhesive applied in a ring shape so as to cross the ring, and then one substrate is stacked on top of the other. It is characterized by

Figures 1 to 3 show the main steps in carrying out the present invention by providing a hollow pipe in the adhesive applied in a ring shape along the outer periphery of the substrate, depending on the conditions near the outer periphery of the substrate and its surroundings. FIG. FIG. 1 shows a state in which the adhesive 3 is applied along the outer periphery of the substrate 1a, and the second
The figure shows a state in which a hollow pipe 5 is provided so as to cross the adhesive 3, and FIG. Note that the pipe may be provided in an adhesive applied in a ring shape along the inner peripheral edge of the substrate.

In the method of the present invention, when transitioning from the state shown in FIG. 2 to FIG. 3, the air in the internal space is released from the pipe to the outside, so the air pressure does not increase and the ring shape of the adhesive is disturbed. Therefore, the adhesive does not stain the edges of the optical information recording disk medium, nor does the adhesive effect or function as a spacer deteriorate. The state of C is maintained as is.

Since the pipe is for communicating between the internal space and the outside world, it is sufficient to provide it so as to cross at least one of the adhesives applied in a ring shape near the inner peripheral edge and the outer peripheral edge. The material of the pipe can be glass, metal, synthetic resin, etc. without any restrictions. If the pipe is to remain in the final product, it is better to remove the part of the pipe that protrudes from the disk end after the adhesive has hardened. It also acts as an air flow hole so that the outer shape of the medium is not substantially changed. If the recording layer is sensitive to moisture, etc., the pipe opening can be closed with epoxy resin, silicone resin, urethane resin, acrylic resin, etc. to seal the internal space. There is a method in which after pressing the two substrates to the final spacing, the pipe is pulled out while the adhesive is not cured, and then the adhesive is cured. In this method, by adjusting the thickness of the pipe and the speed at which the pipe is pulled out, the adhesive can easily flow into and close the tiny gaps left after the pipe is pulled out. In any case, by using a pipe, the internal space can be sealed very easily.

Various methods can be considered to determine the final distance between the two substrates, such as providing a portion of the substrate with a protrusion approximately equal to the distance, or 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 Two disk-shaped transparent polycarbonate substrates with an outer diameter of 200 am and a thickness of 1.2 mm and a center hole of 35 mm diameter were prepared.
One was created. A recording layer was formed by applying a polymethine dye having a light absorption peak around 830° to a thickness of 100 OA using a spinner.

On the other hand, a two-liquid room temperature curing silicone adhesive with a particle size of 0.
Glass beads of 5 to 0.59+am were added and mixed in a weight ratio of LO%. 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 is about 2cm, the height is about 1III11,
The cross-sectional shape was approximately semicircular.

Next, a hollow glass pipe with an outer diameter of 0.4 + a + a, an inner diameter of 0.2 mm, and a length of 7 cm was buried in one spot of adhesive applied in a ring shape near the outer periphery of the board, as shown in Figure 2. It's here.

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 0.61 over the entire surface of the substrate, and the adhesive was applied in a uniform manner along the inner and outer edges of the substrate. It was in the shape of a ring with a width of 3cm, 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 pipe was not embedded in the adhesive applied in a ring shape. 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 substrate spacing after curing at room temperature was approximately 0 and 8 ma+ near the outer periphery, but approximately 0 mm near the inner periphery.
．． It became 80III.

Example 2 Two substrates were overlapped and the distance between the two substrates was adjusted to the final distance in the same manner as in Example 1.

Immediately, the pipe was gently pulled out. The adhesive flowed and sealed the area where the pipe was pulled out. then 24
The adhesive was cured by standing at room temperature for an hour. The completed hollow-structured disk medium according to the present invention had a sealed structure in which the inner and outer circumferences were bonded together with an adhesive that also served as a ring-shaped spacer without disturbance.

〔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 adhesion effect of the adhesive or its function as a spacer does not deteriorate, and the air pressure in the internal space does not increase, so the spacing and parallelism of the substrates can be adjusted. Formed accurately.

[Brief explanation of drawings]

1 to 3 are schematic cross-sectional views showing the main steps of the method of the present invention in the vicinity of the outer peripheral edge of the substrate and the surroundings thereof. Fig. 4 is a schematic cross-sectional view of an optical information recording disk medium with a hollow structure, and Fig. 5 is a schematic diagram showing the process of applying adhesive to a substrate, overlapping another substrate, and bonding both substrates together. FIG. FIG. 6 is a perspective view showing a state in which adhesive is applied in a ring shape near the outer peripheral edge of the substrate. ! a, lb...board, 2a, 2b・
...Recording layer. 3.3a, 3b...Adhesive, 4...
...Inner space, 5...Hollow pipe.

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. 1. An optical information recording disk medium having a hollow structure, characterized in that a hollow pipe is embedded in at least one place of an adhesive coated in a ring shape so as to cross the ring. 2) The optical information recording disk medium according to claim 1, wherein the opening of the hollow pipe is closed. 3) 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. 4) At least one of two disc-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 peripheries. , 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 a hollow pipe is buried in at least one place of an adhesive applied in a ring shape so as to cross the ring, and then both substrates are overlapped. Method. 5) The method for manufacturing an optical information recording disk medium according to claim 4, wherein after the distance between the two substrates is finally determined, the hollow pipe is removed while the adhesive is not cured.