JPH10208317A - Coating applicator for optical disk - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high-quality optical disk by providing a coating device with a turn table, a means for driving the table, a discharge nozzle and a turn table cover, rotating the turn table and sucking a shaken off liquid material. SOLUTION: A substrate 8 is installed on the turn table 7 in such a manner that its reflection film surface faces upward. The substrate is rotated by the rotational driving means 5. The liquid material 2 is dropped from the discharge nozzle 1 near to the center of the substrate 8 under rotation. The substrate of the second sheet is immediately superposed thereon in the direction where the reflection film surface faces downward. The cap 6 of the turn table 7 cover 3 is then closed. Suction is started under 200Torr from the suction part 4 in the cover 3. The application and shaking of the liquid material 2 are executed by setting the number of revolutions of the substrate 8 at a high speed. Next, the bonding substrate is irradiated with the UV rays generated by a high- pressure mercury lamp to cure the liquid material and to adhere the substrates. As a result, both of the front surface and the rear surface are kept free from splashes and stains, etc. The bonding substrate having good appearance is thus obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a coating apparatus for an optical disk. The coating apparatus of the present invention is preferably used, for example, when forming a protective film on an optical disk substrate or when forming an adhesive layer between two optical disks.

[0002]

2. Description of the Related Art An optical disk useful as a high-density information recording medium has a plastic or glass substrate such as polymethyl methacrylate, polycarbonate, or polyolefin, and has pits or pre-groups for information recording on one side. An information surface is formed, and a metal film, an organic dye film, or the like that functions as a recording layer or a light reflection layer is formed on the information surface. There are two types of optical discs, a single-disc disc composed of a single substrate and a double-sided disc having a structure in which the information surfaces of two single-disc discs are bonded to each other. Information is read by inputting a laser beam from the surface opposite to the surface.

The above-mentioned recording layer or light reflecting layer is susceptible to oxidation, and in the case of a single-disc disk, it is widely practiced to apply a protective coat on the recording layer with an ultraviolet curing resin or the like (for example, Japanese Patent Application Laid-Open No. 7-6408). See). On the other hand, in the case of a double-sided disc, in order to bond and bond two single-plate discs,
Ultraviolet curing adhesives, anaerobic adhesives, hot melt adhesives and the like are used.

As a method of applying such a protective film and an adhesive, there are a roll coating method, a spin coating method, a screen printing method and the like. Of these coating methods, a spin coating method with high industrial productivity is often employed. Spin coating is a method in which a liquid material is dropped onto the painted surface of an optical disc substrate and then placed several thousand revolutions per minute around the center of the substrate as a rotation axis, and the liquid material is shaken off and painted to remove excess liquid material. It is.

[0005]

In the conventional method of coating an optical disk substrate by spin coating, the liquid material shaken off by the rotation of the substrate becomes fine mist and drifts around the substrate, and when the rotation of the substrate is stopped, the liquid material is removed. Mist settled down and adhered to the substrate in some cases. This causes dirt, which not only impairs the commercial value, but also in the case of a double-sided disc, the passage of recording / reproducing laser light is hindered, and recording / reproducing may not be possible.

Heretofore, several methods have been studied as methods for preventing the adhesion of such a liquid material.
For example, a coating method using an optical disk substrate whose outer end surface is inclined inward from the information surface toward the opposite surface is known (Japanese Patent Application Laid-Open No. 7-296418). However, this method requires a special outer die mold for the disk, and its application is limited to the painting of a single disk,
There is a problem that it cannot be applied to the bonding of a double-sided disk. There is also known a method of detecting a liquid temperature correlated with the viscosity of a liquid material (ultraviolet curable resin) to be applied and controlling the application conditions (see Japanese Patent Application Laid-Open No. Hei 6-103618). This method is effective for a liquid material having a viscosity of several tens of cps in an actual operating temperature range (15 to 30 ° C.).
When a liquid material of s, several hundreds cps is applied in an actual use temperature range, there is a problem that a change in viscosity cannot be appropriately controlled.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a liquid resin can be applied irrespective of the form of an optical disk substrate and the viscosity of a liquid material to be applied. It is an object of the present invention to provide a device capable of performing such operations.

[0008]

According to an embodiment of the present invention, there is provided an apparatus for rotating an optical disk substrate rotatably, a rotation driving means for the rotary table, and a liquid material on the optical disk substrate. A discharge nozzle for discharging,
A rotary table cover having at least one suction port formed at a position lower than the optical disk substrate supported by the rotary table; and a liquid material connected to the suction port and shaken off by rotating the rotary table. And a suction means for sucking the air.

The apparatus of the present invention can be used for applying a liquid resin when the liquid resin is cured to form a protective film. Further, the apparatus of the present invention is used for forming a bonding layer between two disks by applying a liquid resin on a first optical disk substrate, then laminating a second optical disk substrate, and curing the liquid resin. Can be used to apply the liquid resin.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method of manufacturing an optical disk using the present apparatus will be specifically described while describing the structure of the apparatus of the present invention with reference to FIGS.

On a polycarbonate substrate having an outer diameter of 120.0 mm and a thickness of 0.6 mm having information pits formed on one side by injection molding, an Al reflective film was formed by sputtering so as to have a thickness of 50 nm. As a liquid material applied on this substrate, World Rock No. which is an ultraviolet curable adhesive having a viscosity of 500 cps (25 ° C.) is used. 811LK (Product name:
(Kyoritsu Chemical Industry Co., Ltd.).

Next, the substrate 8 is placed on the turntable 7 (FIGS. 1 and 2) of the coating apparatus according to the present invention so that the surface of the Al reflection film faces upward.
Rotate at pm. 1 ml of the liquid material 2 is dropped from the discharge nozzle 1 near the center of the rotating substrate 8 (see FIG. 1). Immediately, the second substrate is stacked with the Al reflecting film face down, and the lid 6 of the cylindrical rotary table cover 3 having a diameter of 140.0 mm is closed. Suction was started from the four suction ports 4 provided inside the rotary table cover 3 at a degree of vacuum of 200 Torr, the rotation speed of the substrate 8 was set to 3000 rpm at high speed, and the liquid material 2 was applied and shaken off. Next, ultraviolet light generated by a high-pressure mercury lamp was applied to the bonded substrate (not shown) to cure the liquid material and bond the substrate (FIG. 2). The bonded substrate was taken out of the coating apparatus according to the present invention, and its appearance was visually observed. As a result, a bonded substrate having good appearance without splashing or dirt on the front and back surfaces was obtained.

Next, an example of manufacturing a single disk will be described. Same outer diameter as above 120.0mm, thickness 1.2mm
Was formed by sputtering on a substrate made of polymethyl methacrylate having a thickness of 50 nm. As a liquid material applied on the substrate, SD-17 (trade name: UV curable protective coating agent having a viscosity of 28 cps (25 ° C.))
(Manufactured by Dainippon Ink and Chemicals, Inc.).

Next, the substrate is placed on a rotary table of the coating apparatus according to the present invention so that the Al reflective film surface faces upward, and is rotated at a rotation speed of 80 rpm by a rotation driving means. 1 ml of the liquid is dropped from the discharge nozzle near the center of the rotating substrate. Immediately close the lid of the cylindrical rotary table cover with a diameter of 140.0 mm. Suction is started from the four suction ports provided inside the rotary table cover at a vacuum of 200 Tprr, and the number of rotations of the substrate is increased to 3000.
The liquid was applied and shaken off at rpm. Ultraviolet light generated by a high-pressure mercury lamp was applied to the substrate coated with the protective coating solution on the reflective film surface to cure the liquid material on the surface. The substrate was taken out of the coating apparatus according to the present invention, and the appearance was visually observed. As a result, a bonded substrate having a good appearance was obtained without any contamination on the front and back surfaces.

An optical disk obtained by the coating apparatus according to the present invention is compared with an optical disk obtained by the conventional coating apparatus shown in FIG. The same outer diameter as above 120.0 mm,
On a polycarbonate substrate having a thickness of 0.6 mm, an Al reflective film was formed by sputtering so as to have a thickness of 50 nm. As the liquid material to be applied on the substrate, the above-mentioned World Rock No. 811LK was used. The substrate 8 is set on the turntable 7 of the coating apparatus shown in FIG. 3 so that the surface of the Al reflection film faces upward.
Rotate at m. 1 ml of the liquid material 2 is dropped from the discharge nozzle 1 near the center of the rotating substrate 8. Immediately, the second substrate is stacked with the Al reflecting film surface facing down. Immediately, the rotation speed of the substrate was set to 3000 rpm, and the liquid material 2 was applied and shaken off. Next, ultraviolet light generated by a high-pressure mercury lamp was applied to the bonded substrate to cure the liquid material 2 and bond the substrate. The bonded substrate was taken out of the coating device shown in FIG. 3 and its appearance was visually observed.
Splashes, stains, etc. were generated on the surface, and only a bonded substrate having poor appearance was obtained.

[0016]

According to the present invention, the surplus liquid material that has been shaken off is collected by suction, so that no dripping or splashing occurs on the surface of the optical disk substrate after application, and a high-quality optical disk is prevented. Can be manufactured.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a coating apparatus according to the present invention.

FIG. 2 is a schematic sectional view when a liquid material is applied and shaken off by the apparatus of the present invention.

FIG. 3 is a schematic sectional view of a conventional coating apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Discharge nozzle 2 ... Liquid material 3 ... Rotary table cover 4 ... Suction port 5 ... Rotation drive means 6 ... Cover lid 7 ... Rotary table 8 ... Optical disc substrate

Claims (1)

[Claims] A rotary table for rotatably supporting an optical disk substrate; a rotation driving means for the rotary table; a discharge nozzle for discharging a liquid material onto the optical disk substrate;
A rotary table cover having at least one suction port formed at a position lower than the optical disk substrate supported by the rotary table; and a liquid material connected to the suction port and shaken off by rotating the rotary table. A coating device for an optical disk, comprising: a suction unit for sucking a liquid.