JPH0443334B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method of manufacturing an information recording substrate in which information is written and read by optical means such as a laser beam, and in particular, relates to a method of manufacturing an information recording substrate in which information is written and read by optical means such as a laser beam. The present invention relates to a method of manufacturing a disk substrate.

[Conventional technology]

A disk-shaped information recording substrate 1 (hereinafter referred to as disk 1), which is generally used for optical disks, usually has a third
It has a structure as shown in the figure. That is, thin film recording media 3 and 3' are deposited on transparent plastic substrates 2 and 2' made of, for example, acrylic resin or polycarbonate resin, which transmit optical signals.
and 2' are inner peripheral spacers 4 (hereinafter referred to as spacers 4) made of acrylic resin or the like on the inner and outer peripheral parts.
and are bonded to each other with adhesives 6 and 6' via an outer circumferential spacer 5 (hereinafter referred to as spacer 5),
A hollow portion 7 is formed between the recording media 3 and 3'.

Conventionally, there is an invention as described in Japanese Patent Publication No. 57-16445, for example, regarding a method of manufacturing an information recording substrate having an air sandwich structure using spacers 4 and 5. In this invention, as shown in FIG. 2, a disk 1 is placed on a base 8, and an ultraviolet curing adhesive (hereinafter referred to as UV adhesive) is applied to the joint surfaces of spacers 4 and 5 and substrates 2 and 2'. ) until the layer thickness becomes uniform. After this leaving, the disk 1 is irradiated from above with a UV lamp (ultraviolet lamp) 9 to harden the UV adhesive.
As a result, there is an advantage that the adhesive layer on the joint surface is uniform.

[Problem that the invention seeks to solve]

However, in such a conventional method for manufacturing information recording substrates, the UV lamp 9 is installed only at one location above the disk 1, so the irradiated ultraviolet light passes through the substrate 2 of the disk 1 and hardens the adhesive layer 6. However, if the light is attenuated or cut by the spacers 4 and 5, the substrate 2' and the spacer 4,
The adhesive layer 6' between the adhesive layers 5 and 5 remains uncured. Therefore, disk 1 is turned over and irradiated with ultraviolet rays again, but this not only causes misalignment and uneven adhesion, but also has disadvantages such as the need to turn disk 1 and irradiate it twice, which increases the number of manufacturing steps. .

Additionally, the lamp used to cure the UV adhesive is several kilowatts.
Since the output is high and the temperature is quite high during irradiation, the lamp 9 is used for unilateral irradiation as shown in Figure 2.
A temperature difference occurs between the substrate 2 on the side and the substrate 2' on the base 8 side, making it impossible to manufacture a disk without warping.

An object of the present invention is to provide a method for manufacturing an information recording substrate that solves these problems.

[Means for solving problems]

The method for manufacturing an information recording substrate of the present invention is based on an Air Sun Germany method in which two disc-shaped substrates each having a center hole are bonded together with an inner circumferential spacer and an outer circumferential spacer each sandwiching an inner circumferential spacer and an outer circumferential spacer each having a center hole in the inner and outer circumferential portions. In the method for manufacturing an information recording substrate of manufacturing an information recording substrate having a structure, the shaft has a shaft in the center that fits into the center hole of the two substrates and the inner circumferential spacer, and a shaft that fits in the outer circumferential spacer at the outer circumferential part. A step of applying an ultraviolet curable adhesive to the joint surfaces of each other on a base having a positioning guide and transmitting ultraviolet rays, and placing the two substrates, the inner circumferential spacer and the outer circumferential spacer; and after this step. A step of pressurizing the joint surface of the substrate with a presser plate that transmits ultraviolet rays, and after this step, the two stacked substrates are simultaneously irradiated with ultraviolet rays from both sides to cure the ultraviolet curable adhesive. The method includes a step of causing

[Effect]

By simultaneously irradiating both sides of the disk 1 with a UV lamp, the adhesive layers 6 and 6' applied to the joint surfaces of the two substrates 2 and 2' and the spacers 4 and 5 are simultaneously cured in a few seconds, thereby preventing positional misalignment. Also, there is no uneven adhesion, and the number of manufacturing steps is greatly reduced. Furthermore, by irradiating both sides of the disk 1 at the same time, the illuminance pattern and heat distribution on the substrates 2 and 2' are uniform, which has the advantage that the warpage and adhesive strength of the substrates 2 and 2' on both sides are uniform. be.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a sectional view showing one embodiment of the present invention. The manufacturing method of the disk 1 in this embodiment is as shown in FIG. 1, in which a round hole in a transparent substrate 2' made of acrylic resin or polycarbonate resin is fitted into a shaft 11 located at the center of a base 10, and a recording medium 3' The substrate 2' is placed on the base 10 so that the substrate 2' faces upward. Next, apply UV adhesive (for example, UV adhesive manufactured by Toagosei Kagaku Kogyo Co., Ltd.
-3000 series, etc.) using a dispenser, etc. Subsequently, a spacer 4 made of the same material as the substrate 2' is placed along the axis 11, and a spacer 5 is placed along the base 1.
When the spacers 4 and 5 are inserted along the positioning guide 13 provided at 0 and placed on the substrate 2', an adhesive layer 6' is formed between the substrate 2' and the spacers 4 and 5. Next, place it again on spacers 4 and 5.
Apply UV adhesive, fit the round hole of the substrate 2 into the shaft 11 from above, and place the substrate 2 on the spacers 4 and 5 with the recording medium 3 facing down. An adhesive layer 6 is formed between them, and the disk 1 is assembled. Furthermore, by placing the presser plate 14 on the disk 1 and applying pressure, the flow of the adhesive is improved, and adhesive layers 6 and 6' without uneven adhesion can be formed. Transparent plates may be used for the base 10 and the presser plate 14, but the light transmittance is
If quartz glass is used, which cuts out 95% or more of the long wavelength region, it will sufficiently transmit ultraviolet rays and block infrared rays when irradiated with a UV lamp.
2' can be prevented from increasing. Furthermore, the surfaces of the base 10 and the presser plate 14 that contact the areas on which the recording media 3 and 3' of the substrates 2 and 2' are deposited may be flat, but grooves 12 and 15 that are treated to make them opaque are provided. In this case, since the ultraviolet rays during irradiation do not directly hit the recording media 3 and 3', deterioration of the recording media 3 and 3' due to ultraviolet rays and heat can be prevented. Next, high-pressure mercury lamps (UV
By simultaneously irradiating the adhesive layers 6 and 6' with the lamps 9 and 9' for several seconds, the adhesive layers 6 and 6' are simultaneously solidified, producing a disk 1 having a so-called air sandwich structure.
During this irradiation, if the difference in the illuminance of the ultraviolet rays irradiated to substrates 2 and 2' of disk 1 becomes unbalanced by 20 mw/ ^cm2 or more, the substrate side with higher illuminance will have a lower illuminance than the substrate side with lower illuminance. As the temperature rises, the substrate becomes more easily deformed, resulting in a warped and unbalanced disk. Therefore, the distance between the UV lamps 9 and 9' and the disk 1 must be such that the difference in the illuminance of the ultraviolet rays hitting the substrates 2 and 2' is always 20 mw/cm ² or less.

Furthermore, during ultraviolet irradiation, the disk 1 may be in a stationary state, but generally the UV lamps 9 and 9'
The illuminance in the longitudinal direction is almost constant for the disk 1 under the lamp and above the lamp, but the illuminance in the axial direction decreases with distance, so when the disk 1 is stationary, it is always uneven. The disk becomes slightly undulating in the circumferential direction due to the ultraviolet rays of the illuminance distribution and accompanying heat distribution. Therefore, if the disk 1 is rotated during the irradiation period, all areas will receive ultraviolet rays of the same intensity, and the above-mentioned problem will be solved and a disk without waviness will be obtained.

〔Effect of the invention〕

As explained above, the present invention applies UV adhesive to the joint between a spacer and two substrates, presses the two substrates using a base and a presser plate that transmit ultraviolet rays, and then connects the two substrates. The substrate is irradiated with ultraviolet rays from both directions at the same time, the UV adhesive is cured, and the substrate and spacer are bonded together, so there is no uncured adhesive layer compared to when irradiating from one side, and the resulting misalignment and uneven adhesion are eliminated. Not only does it eliminate this problem, but it also cures with one irradiation, which can reduce the number of manufacturing steps.
Furthermore, when both sides are irradiated simultaneously, a uniform illuminance distribution and heat distribution can be obtained on both sides of the substrate, so it is possible to obtain an information recording substrate with an air sand arch structure that has excellent parallelism between the substrates and is free from waviness and distortion. be.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing one embodiment of the present invention, and FIG.
The figure is a cross-sectional view showing an example of a conventional method for manufacturing an information recording substrate, and FIG. 3 is a cross-sectional view of a general information recording substrate. 1... Information recording board, 2, 2'... Substrate, 3,
3'... Recording medium, 4... Inner spacer, 5...
Peripheral spacer, 6, 6'...adhesive layer, 7...hollow part, 8...base surface, 9,9'...UV lamp, 10
... Base, 11 ... Shaft, 12, 15 ... Groove, 13
...Positioning guide, 14...Press plate.

Claims (1)

[Claims] 1. Information for manufacturing an information recording substrate with an air sandwich structure in which two disc-shaped substrates each having a center hole are bonded together with an inner circumferential spacer and an outer circumferential spacer each having a center hole sandwiched between the inner and outer circumferential portions. In the method of manufacturing a recording substrate, the substrate has a shaft in the center that fits into the center hole of the two substrates and the inner spacer, a positioning guide that fits in the outer spacer on the outer periphery, and transmits ultraviolet rays. A step of applying an ultraviolet curable adhesive to the joint surfaces of each other on a stand and placing the two substrates, the inner peripheral spacer and the outer peripheral spacer, and after this step, applying ultraviolet rays to the joint surfaces of the substrates. and a step of curing the ultraviolet curable adhesive by simultaneously irradiating the two stacked substrates with ultraviolet rays from both directions after this step. A method for manufacturing an information storage board.