JPS62164242A - Production of disk carrier for optical information recording and reproduction - Google Patents

Abstract

PURPOSE:To prevent warping during curing and to obtain the titled high-quality carrier by uniformly irradiating rays on the whole surface of an optical disk including the part to be coated and the part not to be coated with a material when the liq. UV curing material is cured and formed on the surface of the optical disk. CONSTITUTION:An optical disk 5 coated with an UV curing material 6 is mounted on a holder 8. The UV curing material 6 on both surfaces are simultaneously cured by strip UV rays 11 radiated from a UV ray generating cured by strip UV rays 11 radiated from a UV ray generating lamp 10 and a reflecting mirror 9 and connecting the central hole 4 of the optical disk 5 and the outer periphery while rotating the optical disk 5 by a rotating shaft 7 to form a light-transmitting hard coated film 6'. The holder 8 is made of a light- transmitting resin, the rotating shaft 8 is thinned, and the rays are uniformly irradiated even on the part not to be coated with the UV curing material 6. Consequently, the resinous substrate 5 is thermal-expanded uniformly, and warping can be prevented during curing.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method of manufacturing a disc carrier for optical information recording and reproducing, and in particular, forming a hard coating on the surface of the disc carrier for optical information recording and reproducing which is in contact with the atmosphere. The present invention relates to a method of manufacturing a disc carrier for optical information recording and reproducing according to the method.

2. Description of the Related Art In recent years, so-called optical disk devices that optically record and reproduce information using laser beams have attracted attention as high-density, large-capacity recording and reproducing devices.

This means, for example, that the light from a semiconductor laser etc. has a diameter of 1 μm3-.
By irradiating the optical disk recording member with a laser beam focused to a certain degree, the width of the recording member is 0.5 to 1 μm and the length is 1 to 2 μm.
? Information is recorded by forming bits of + or so on a recording member, and this focus is reproduced using a similar laser beam. Conventionally, such optical information recording and reproducing disk carriers (hereinafter referred to as optical disks) have been produced through a process of forming a recording member that can optically record and reproduce on a circular light-transmitting resin substrate. Accordingly, it has been common to use two light-transmissive resin substrates, which are superimposed and bonded together to protect the recording member. The problem with this conventional method is that the substrate of the recording member and the light-transmitting resin substrate used for protection get scratches on the surface due to contact with dust or foreign matter during manufacturing, resulting in noise in recording and reproduction signals during recording and reproduction of optical discs. There was a problem with it appearing. On the other hand, it has been found that by applying an ultraviolet curable material to the surface of an optical disk manufactured by a conventional method and curing it to form a light-transmitting hard coating, a remarkable scratch-preventing effect appears ( For example, Japanese Patent Application Laid-Open No. 58-45637). An example of such an optical disc is not shown in a sectional view in FIG. In Figure 4(d), 1
is a light-transmissive resin substrate, 2d recording member, 3 is an adhesive, and 6'
is a light-transmitting hard coating.

Further, FIGS. 4(b) and 4(c+) are sectional views of an apparatus for curing and forming a light-transmitting hard coating. A method for forming a light-transmitting hard coating will be explained using FIG. Figure 5 (b
), a dip bath 9 is filled with an ultraviolet curable material 6, and a conventional optical disk 5 is mounted on a rotating shaft 7 with a support 8, and the ultraviolet ray curable material 46 is simultaneously applied to both surfaces while rotating. Next, as shown in FIG. 6(c), while the optical disk 6 is being rotated by the same rotating shaft 7 as during coating, ultraviolet rays are emitted from the ultraviolet lamp 1o and the reflecting mirror 9 onto the area where the ultraviolet curable material 6 is applied. The light-transmitting hard film 6' is formed by simultaneously curing both sides of the ultraviolet curable material 6 by the irradiation step 11.

Problems to be Solved by the Invention However, in the method for forming a light-transmitting hard coating described above, it is difficult to obtain an optical disc without warpage;
This has caused a new problem in that warpage occurs over time after formation.

In other words, with an optical disk having a large warp, it is difficult to maintain a constant distance between the semiconductor laser beam head and the optical disk, making it impossible to record and reproduce signals, and conversely deteriorating the performance of the optical disk. This is due to the following reasons.

This method involves attaching the center hole of an optical disk to a rotating shaft to form a light-transmissive hardened film.In addition, the center hole diameter and the flatness of the area around the center hole are determined. Because of this need, it is necessary to form it in a portion of the optical disc excluding the vicinity of the center hole. In this case, only the portion of the ultraviolet curable material is often formed by irradiating ultraviolet rays. Therefore, there is a difference in thermal expansion of the light-transparent resin substrate between the part coated with the UV-curable material and the part not coated with the UV-curable material. This causes warpage. This warping becomes more pronounced as a resin substrate having a lower thermal conductivity and a higher coefficient of thermal expansion is used. Conventionally, the warping of 6''''-pas has been suppressed by forcibly confining the ultraviolet curable material under specific conditions in which both sides are simultaneously cured. In other words, we realized that warping changes are accumulated, and that the release changes of this accumulation are warping that appears over time.

Therefore, the present invention has been made in view of these points, and it is possible to prevent the occurrence of warping of an optical disc during the formation of a transparent cured film using a simple method, and to produce a high-quality optical disc that does not warp over time. The purpose is to provide a method.

Means for Solving the Problems The technical means of the present invention for solving the above problems is to set an optical disk on a rotatable rotating shaft having a support made of a light-transmitting material, and while rotating it, an ultraviolet curable material is used. The entire surface of the coated and non-coated areas is uniformly irradiated with ultraviolet rays from an ultraviolet generating lamp to cure the ultraviolet curable material and form a light-transmissive hard coating.

For production The effect of this technical means is as follows.

7-7 That is, by uniformly irradiating the entire surface of the light-transmissive resin substrate, including both the coated and non-coated parts of the UV-curable material, to cure and form the UV-curable material, the coated and non-coated parts are cured. Thermal expansion of the resin substrate acts uniformly over the entire surface of the optical disc, thereby weakening the large warpage of the optical disc.

As a result, it is possible to prevent the optical disc from warping during the formation of the light-transmitting hard coating, and to obtain a high-quality optical disc that does not warp over time.

Embodiment The optical disc used in the present invention consists of three parts as shown in FIG. 3(a). A circular light-transmitting resin substrate 1 made of, for example, polycarbonate and having a hole 4 in the center, a diameter 13Offlff and a thickness of 1.2 mm.
After forming a recording member 2 capable of optically recording and reproducing, another light-transmitting resin substrate 1 formed in the same manner is bonded with an adhesive 3.
are superimposed by More specifically, this recording member utilizes the principle of changing the reflectance or transmittance of the recording member by causing a phase transition by irradiation with a laser beam.
A thin film mainly composed of (2) is used. The adhesive used is a pressure adhesive that hardens by applying pressure after application.

The method of applying the ultraviolet curable material 6 is as shown in FIG. 3(b).
When attaching the optical disc to the support base 8 of the rotating shaft 7, the ultraviolet curable material 6 is applied between both sides of the optical disc 50 while rotating.
is applied.

The method for manufacturing an optical disc according to the present invention will be explained below.

FIG. 1 is a cross-sectional view of one embodiment of the method of curing and forming an ultraviolet curable material of the present invention. In FIG. 1, reference numeral 6 denotes an ultraviolet curable material U110, an ultraviolet generating lamp, 9 a reflecting mirror, and 7 a rotating shaft.A supporting base 8 consisting of a table 8a and a clamp 8b is fixed to the rotating shaft 7. An optical disc 5 coated with an ultraviolet curing material 6 is attached to a support stand 8. Next, while rotating the optical disk 6 with the rotating shaft 8, the ultraviolet curable material 6 is simultaneously applied to both surfaces by the band-shaped ultraviolet ray 11 that connects the center hole 4 of the optical disk 5 and the outer periphery of the vane 9 and the center hole 4 of the optical disk 5 emitted from the ultraviolet ray generating lamp 1o and the reflecting mirror 9. It is cured to form a light-transmitting hard coating 6'. At this time, the support base 8 is made of a light-transmitting resin such as acrylic resin, and the ultraviolet rays are uniformly irradiated near the center hole 4 of the optical disk, that is, the non-coated area 1 of the ultraviolet curable material 6. It is configured so that it can be done. Further, the rotating shaft 7 is made as thin as possible so as not to be affected by the ultraviolet rays. With the above, the center hole 4 of the optical disc
It is possible to uniformly irradiate the entire surface including the vicinity, that is, the uncoated portion of the ultraviolet curable material 6, with the ultraviolet rays 11 from the ultraviolet generating lamp 10. As a result, the thermal expansion of the resin substrate caused by the irradiation light including ultraviolet rays emitted from the ultraviolet ray generating lamp when the ultraviolet curable material is cured and formed acts uniformly, thereby weakening the large warpage of the optical disk. In addition, by preventing warping during hardening, it was confirmed that no warping occurred after 100 hours in a forced deterioration test in an atmosphere at 100°C, 80%, and 70 hours under accelerated conditions equivalent to 10 years of deterioration of a recording member. I confirmed it.

10'- Next, other embodiments of the present invention will be described.

FIG. 2 shows another embodiment of the present invention, in which the support base 8 is attached with a clamp table made of metal and resin in the shape of a claw in FIG. 2(a). In FIG. 2(b), a clamp table having a mesh-shaped configuration is attached. With any of these configurations, more uniform irradiation light can be obtained, and as in the first embodiment, a method of manufacturing an optical disk with small warpage can be obtained. Note that these effects L1: By providing a slight gap between the support base and the diameter of the center hole of the optical disk, a relief is created at the middle periphery due to thermal expansion of the resin substrate, thereby further emitting light. Furthermore, it has been confirmed that warpage is similarly weakened in optical discs configured such as CDs (compact discs) and in optical discs in which a light-transmitting hard coating is formed on one side.

Effects of the Invention As described above, the present invention provides the following advantages: When a liquid ultraviolet curable material is cured and formed on the surface of a source disk, the source disk 11 includes an area coated with the ultraviolet curable material and a portion not coated with the ultraviolet curable material. By using a simple means to uniformly irradiate the entire surface with irradiation light from an ultraviolet generating lamp, it is possible to reduce the difference in thermal expansion distribution of the light-transmissive resin substrate during curing and forming, thereby preventing warping during curing and forming over time. At the same time, it is possible to stably manufacture high-quality optical discs without warping, which has great practical effects.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of an apparatus showing a method of manufacturing a 7' isk carrier for optical information recording and reproduction in one embodiment of the present invention;
The figure is a perspective view of a main part of an apparatus according to another embodiment of the present invention, and FIG. 3 is a sectional view of a disk and apparatus showing a conventional method of manufacturing a disk carrier for optical information recording and reproduction. 5... Disc carrier, 6... Ultraviolet curable material, 7... Rotating shaft, 8... Support stand, 9...
Reflection mirror, 10... Ultraviolet generating lamp, 11.
...Ultraviolet rays/Name of agent Patent attorney Toshio Nakao and 1 other person δ---Te'isk Jdan set 6-E Tato blade ni Tsuji 1 Iz'EL material rod call 7--- Rotation, Chapter 6--- Emochiai/I--Ichigo Tatoyo Figure 2 Figure 3!

Claims (4)

[Claims] (1) A liquid ultraviolet curable material is coated on the surface of the optically transparent resin substrate of the optical information recording/reproducing disk carrier through which at least the laser beam passes and is cured to make the substrate thinner and harder than the optically transparent resin substrate. In the method of forming a light-transmitting hard coating, the optical information recording/reproducing disk carrier is set on a rotatable support and while being rotated, ultraviolet rays are uniformly applied to the entire surface of the areas coated with the ultraviolet curable material and the areas not coated. 1. A method of manufacturing a disc carrier for optical information recording and reproducing, characterized in that the ultraviolet curable material is cured by irradiation with UV light. (2) The optical system according to claim 1, wherein the ultraviolet rays are obtained from an ultraviolet generating lamp arranged so that the ultraviolet rays are emitted in a band-like manner on a line connecting the center hole and the outer periphery of the optical information recording/reproducing disk carrier. A method of manufacturing a disc carrier for information recording and reproduction. (3) A method for manufacturing a disc carrier for optical information recording and reproducing according to claim 1 or 2, which comprises a clamp and a table whose rotatable support base is made of a light-transmitting resin. (4) A method for manufacturing a disc carrier for optical information recording and reproducing according to claim 1 or 2, wherein the rotatable support base comprises a claw-like or mesh-like clamp and a table.