JPH01220156A - Manufacturing instrument for substrate for optical disk - Google Patents

Abstract

PURPOSE:To make the flowing-in of resin smooth, to erase the residue of a bubble and to prevent drop-out from being generated by adding roundness or providing inclination to side surface which contacts to the moulding space of a stamper, a nozzle and an outer circumference ring. CONSTITUTION:For an injecting nozzle 7, a round part 9 is provided on a nozzle side surface 11 which is in the outer side of a notch 10. Further, the round part 9 is provided on an outer circumference ring side surface 12 as well. Thus, the flowing-in of the resin can be made smooth and the residue of the bubble is erased in a border part. Then, the drop-out can be prevented from being generated. The same effect can be obtained even when the giving of the roundness is replaced with providing the inclination.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical disc substrate for storing, recording, and reproducing images, information, etc., and particularly relates to an apparatus for manufacturing the same.

[Conventional technology]

Optical disc substrates used for digital audio discs, video discs, write-once optical discs, etc. have a thickness of approximately 1.
It consists of information patterns such as grooves and pits formed on the surface of the dragon's transparent plate.

Conventionally, the following methods have been known for forming these optical disk substrates. That is, <1> A method of injecting and molding a polymeric material such as polycarbonate or polymethyl methacrylate into a mold in which a metal stamper having an information pattern such as a groove or pit is placed [Nikkei Mechanical P34 (1982-2-1) ), Nikkei Electronics P133 (1982-6-7)).

2) A method of attaching a photocurable resin thin film with an information pattern to the surface of a transparent support plate prepared in advance (Japanese Patent Laid-Open No. 53
-86756, JP-A-55-152028).

3> After injecting a thermosetting resin or a photocurable resin into the space created by facing a stamper with an information pattern and a flat plate without a pattern, the resin is cured by heating and light irradiation, and the stamper and flat plate are removed. A method for obtaining a transparent substrate with an information pattern made of a cured resin.

It is.

However, the optical disc substrate obtained by 1)
Because it is difficult to completely remove the molecular orientation that occurs when a polymer material flows and solidifies, optical anisotropy tends to occur within the substrate, and the shape of the information pattern is not faithfully transferred from the stamper to the substrate. Therefore, the operating characteristics of the optical disc tended to deteriorate.

The optical disc substrate obtained by method (2) requires a transparent support to be manufactured in advance, which tends to complicate the process and increase the price.

Although method (3) has the potential to solve the drawbacks of methods (1) and (2), the conventional methods have the following problems.

That is, in the general method (3), as shown in FIG. A thermosetting resin or a photocuring resin is filled through the injection nozzle 7 and cured by heating the entire body or by irradiating light from at least one of the flat plate 1 and the stamper 2.

The polymeric resins commonly used here, such as acrylate, methacrylate, polythiol, and epoxy, have a lower viscosity than injection molding resins and have high fluidity, so when filled into the mold, the diameter is 0.01 to 1 fl. It is easy to entrain some bubbles, which causes dropouts during disk operation.

Attempts to solve this problem include (1) a method in which the injection port is lowered to the same height as the stamper during resin injection, and (2) a method in which the entire mold is depressurized.

However, according to these methods, in the method <1>, the resin invades the sliding part and causes flakes.

In method 2), the mechanism becomes complicated, and if the degree of vacuum is increased too much, soluble gases and low boiling point components in the resin will gasify.
New air bubbles are likely to be generated, and if the degree of vacuum is lowered too much, there is a problem that air bubbles trapped during resin filling will not disappear.

In the figure, 3 is an outer ring, 4 is a photocurable resin, 5 is a resin reservoir space, 6 is a light source, 8 is an injection valve, 10 is a notch,
18 indicates an adhesive.

Note that the notch 10 is provided to reduce the thickness of the resin at that portion to facilitate cutting and molding into a circular shape.

[Problem that the invention seeks to solve]

This invention was made in order to solve the above-mentioned problems, and an object of the present invention is to provide a manufacturing apparatus that can easily manufacture an optical disk substrate with good recording and reproducing characteristics that does not cause dropouts due to air bubbles. That is.

[Means to solve the problem]

The above purpose is to make the angle between the stamper with an information pattern or the stamper or the flat plate not 90 degrees but rounded by the side surface that contacts the molding space of at least one of the injection nozzle fitted into the flat plate and the outer circumferential ring. Alternatively, by providing a slope, the flow of the resin into the molding space is smoothed, and this is achieved by preventing air entrainment on the side surface of the injection nozzle and air bubbles remaining in the outer ring. In this case, the roundness and slope do not necessarily correspond to the injection nozzle,
It is not necessary to provide it directly on the outer circumferential ring, but it may be provided on a ring member that is connected to these.

〔Example〕

Hereinafter, this will be explained in detail with reference to Examples.

Example 1 As shown in Fig. 1 (Ta), a quartz flat plate 1 with a thickness of 10 nm and an outer diameter of 180 mm and a nickel stamper 2 with an inner diameter of 17 fl and an outer diameter of 128 nm were placed facing each other with a distance of 1.3 fins. The injection molding device is placed in parallel with each other, has a step of 1 crane in width on the outside of the notch 10 with a height of 1.21 m and an outer diameter of 15 m, and has a rounded part 9 with a radius of 0.4 crane at the part where the step touches the nozzle side surface 11. There is a step with a width of 1 dragon on the inside of the nozzle 7 and a notch 10 with a height of 1.2 fins and an inner diameter of 130 dragons, and a rounded part 9 with a radius of 0.4 crane is attached to the part where the step touches the outer ring side surface 12. A mold was created in which the outer ring 3 was fitted into the stamper 2.

FIG. 2B shows an optical disk substrate obtained by such a manufacturing apparatus.

Example 2 As shown in Fig. 2, a quartz flat plate 1 with a thickness of 10 fins and an outer diameter of 180 fl and a nickel stamper 2 with an inner diameter of 15 mm and an outer diameter of 130 fl are placed facing each other with an interval of 1.3 ts. Notch 1 with a height of 1.2 fl and an outer diameter of 14.4 fl.
0, and the angle θ1 that the nozzle side surface 11 forms with the stamper 2
An injection nozzle 7 with a diameter of 105a, a notch 10 with a prong length of 1.2 fl and an inner diameter of 130.6 m, and an outer ring 3 with an angle θ2 of 105'' between the ring side surface 12 and the stamper 2 were fitted into the stamper 2. A mold was created.It should be noted that θ2.
θ2 is preferably in the range of too' to 135'.

FIG. 3 shows an enlarged sectional view of a main part according to a modification, in which instead of forming a rounded part on the injection nozzle itself, a ring member 19 on which a rounded part 9 is formed is fitted into this injection nozzle 7. It's okay.

For each example, acrylic and methacrylic resins (30% by weight of dipentaerythritol hexaacrylate, 40% by weight of the reaction product of 1 mole of isophorone diisocyanate and 2 moles of 2-hydroxyethyl acrylate) were injected into the mold through the nozzle 7. , isobornyl methacrylate 2
9% by weight, 1% by weight of 1-hydroxycyclohexyl phenyl ketone) 4 was injected at a discharge rate of 0.8 ml/see, and when the photocurable resin 4 entered about half of the resin reservoir space 5, the injection was carried out. Valve 8 was closed to stop the injection. Resin viscosity is 2
It is about 7000 cps at 5°C. Then, the photocurable resin 4 was cured by the light source 6. Next, the cured photocurable resin is removed from the quartz flat plate 1 and the nickel stamper 2, and the first
A substrate 13 with an information pattern shown in Figure (b) was obtained. Regarding the obtained substrate 13, bubbles having a diameter of 0.1 m or more in the substrate were counted by visual inspection.

As a comparative example, like the conventional example shown in FIG. 4,
A quartz flat plate 1 with a thickness of 10 m, an inner diameter of 15 fl, an outer diameter of 130
+n nickel stampers 2 are placed facing each other with an interval of 1.3 cm, and have a notch 10 with a height of 1.2 fl and an outer diameter of 15 m, and the angle between the nozzle side surface 11 and the stamper 2 is 90''. injection nozzle 7 and the height!, 21[l
A mold was made in which an outer ring 3 having a notch 10 with an inner diameter of 130mm and an angle of 90'' between the ring side surface 12 and the stamper 2 was fitted into the stamper 2, and a substrate was prepared in the same manner and mixed. Bubbles were counted.

The average values for each of the 10 molded substrates are shown in the table below.

In the comparative example, as shown in FIG.
When the injection nozzle 7 and the stamper 2 come into contact with each other, residual air 15 is generated at the boundary between the injection nozzle 7 and the stamper 2, and during resin injection into the molding space, it is carried into the molding space 14 by the resin flow 17 and forms air bubbles 16 (Fig. 5). (b)).

Further, at the outer periphery, as shown in FIG. 5 (C1), when the photocuring resin 4 comes into contact with the outer ring 3, residual air 15 is generated at the boundary and becomes large bubbles.

Although the bubbles in the outer circumferential portion do not affect the recording/reproducing characteristics of the substrate I3, they not only pose a problem in terms of appearance, but also make the substrate more likely to break when dropped.

On the other hand, in Example 1, a rounded part 9 is attached to the side surface of the injection nozzle 7 and the outer ring 3, and in Example 2, the side surface of the injection nozzle 7 and the outer ring 3 is sloped (tapered), so that the resin The flow of air became smoother, air remained at the boundary, and the number of air bubbles was drastically reduced.

In this example, the substrate was molded using a photocurable resin, but the present invention can also be applied to molding using a thermosetting resin.

Further, in this embodiment, a mold in which the injection nozzle 7 and the outer ring 3 were fitted into the nickel stamper 2 was used, but the present invention can also be applied to a mold in which the injection nozzle 7 and the outer ring 3 are fitted into the flat plate 1. Applicable.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to supply an optical disc substrate with excellent recording and reproducing characteristics without dropout at high speed and at low cost.

[Brief explanation of the drawing]

FIG. 1 (al is a vertical cross-sectional view of an optical disk substrate manufacturing apparatus according to the first embodiment of the present invention, FIG. 1 (b) is a vertical cross-sectional view of the optical disk substrate, and FIG. FIG. 3 is an enlarged longitudinal sectional view of a main part showing a modification of the first embodiment, and FIG. 4 is a vertical sectional view of a manufacturing apparatus according to a conventional example. Figures 5(c) and 5(c) are cross-sectional views of essential parts showing the bubble generation mechanism using the conventional manufacturing apparatus, and Figure 5!d) is a cross-sectional view of the substrate obtained using the conventional manufacturing apparatus. DESCRIPTION OF SYMBOLS 1... Transparent plate, 2... Stamper, 3... Outer ring, 4... Photocurable resin, 5... Resin reservoir space,
6... Light source, 7... Injection nozzle, 8... Injection valve,
9... Rounded part, 10... Notch, 11... Nozzle side surface, 12... Outer LJ ring side surface, 13... Optical disc substrate, 14... Molding space, 15... Residual air , 16... Air bubbles, 17... Resin flow, 19... Ring member. Figure 1 (a) (b) ゛ \ Figure 2 January Figure 3 Figure 4 Figure 5 (Q) +6 (b) \ 16 (d)

Claims (1)

[Scope of Claims] (1) A stamper having an information pattern and a flat plate without a pattern are arranged facing each other, and at least one of an injection nozzle and an outer peripheral ring is fitted into at least one of the stamper and the flat plate, In an optical disc substrate manufacturing apparatus in which a molding space is filled with an uncured synthetic resin from an injection nozzle and the resin is cured to obtain a substrate with an information pattern, the molding space is formed on at least one of the injection nozzle side and the outer peripheral ring side. 1. An apparatus for manufacturing an optical disc substrate, characterized in that an air escape portion is provided at the boundary between the stamper or the flat plate fitted in the side surface that contacts the stamper. (2) The apparatus for manufacturing an optical disk substrate according to claim (1), wherein the air escape portion is a rounded portion formed directly on a side surface of an injection nozzle or a side surface of an outer peripheral ring. (3) The optical disc substrate manufacturing apparatus according to claim (1), wherein the air escape portion is a tapered portion formed directly on a side surface of an injection nozzle or a side surface of an outer peripheral ring. (4) The apparatus for manufacturing an optical disk substrate as set forth in claim (1), wherein a ring member having the air escape portion formed thereon is fitted to the outer peripheral portion of the injection nozzle.