JP2002326256A - Method and apparatus for manufacturing optical disk substrate - Google Patents

Abstract

(57) [Summary] [Problem] The quality of a resin injected from a nozzle tip is deteriorated because a flow path is changed at right angles to a product part, and a flow velocity is reduced, thereby deteriorating birefringence characteristics. There is. SOLUTION: A resin material is injected from an axial center of one of the optical disk substrates of opposing dies 2, 10 toward the other die 2, and the flow of the resin material immediately after the injection is applied to the optical disk substrate. It is changed at an obtuse angle in the radial direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and an apparatus for manufacturing an optical disk substrate.

[0002]

2. Description of the Related Art In recent years, optical discs have received much attention from various industries. In recent years, where a dramatic increase in storage capacity and digitization are required, in order to cope with the increase in capacity and digitization, DVDs, which are a kind of optical disc, are appearing on the market. Optical discs manufactured as DVDs
It is manufactured by laminating two molded bodies. An example of the above-mentioned conventional molded body, a molding method thereof, and a method of laminating the molded bodies in such a bonding type optical disk will be described below with reference to the drawings.

Conventionally, a disk molded body is molded by a molding apparatus as shown in FIG. Note that the molding device has a concentric structure about the central axis 4. The molding device is capable of opening the mold, and has two molds 2 for forming a gap 5 for molding a disc molded body when the mold is clamped.
And a mold 10. A stamper 3 for engraving information on a molded disk is fixed to the mold 10 by a stamper holder 9 and an outer stamper holder 14, and a resin material is injected to mold the molded disk. A sprue 6 is formed. On the mold 2 side, a gate cutter 11 is movably mounted along the central axis 4 at a central portion of the disk molded body to be molded, and furthermore, an eject rod 7 slidable with respect to the gate cutter 11. Is provided. During the molding of the disk molded body, the eject rod 7 forms a recess called a slag well 13.

[0004] The molding of a disk molded body using such a molding apparatus is performed as follows. After the stamper 3 is attached to the mold 2, the mold 2 and the mold 10 are formed between the mold 2 and the mold 10 when the mold 2 is closed. The resin material is filled, and the irregularities 8 engraved on the stamper 3 are transferred to the resin material. After the transfer of the irregularities 8, the filled resin material is cooled. During or after the cooling, the gate cutter 11 is moved upward and punched out. After cooling, the resin material present in the mold 2 and the sprue 6 is pushed up with the molded body to be the disk molded body formed by the gap 5, and the mold 2 is pressed.
From the molded article. After the end of the eject operation,
The above-mentioned molded body is transferred to the outside of the molding device by the take-out machine.

[0005] The two molded bodies thus formed are bonded together with an adhesive by a bonding method described below. At the time of this bonding, as shown in FIG.
An inclined portion 24 is provided at the outer peripheral end of each of Oa and 20b.

With respect to the two molded bodies 20a and 20b, the recording surfaces 22 and 22 thereof are opposed to each other, are arranged on a concentric axis by a positioning pin 31, and the nozzle tip 33 of the dispenser 32 is brought into the gap. . Then, after injecting the adhesive into the inner peripheral side of the recording portion of each of the molded bodies 20a and 20b, the dispenser 32 is removed. Then, the compacts 20a, 20b are pressed in the thickness direction, and the compacts 20a, 20b are pressed by a suction device 35 through a suction pipe 34 formed inside the positioning pin 31.
The adhesive is sucked from the central portion of the moldings 20a, 20b.
The adhesive is uniformly diffused in the inner peripheral portion of b. Next, the compacts 20a and 20b are rotated at high speed around the axis in the same direction, and the adhesive diffused to the inner peripheral portions is diffused to the outer peripheral portions of the compacts 20a and 20b. Thereafter, the adhesive spread on the recording surfaces 22, 22 of the molded bodies 20a, 20b is cured by irradiation with ultraviolet rays, and the bonding of the two molded bodies 20a, 20b is completed.

[0007] In the above description, 2
Although the case where the recording surface is formed on each of the molded bodies 20a and 20b is taken as an example, the recording part may be formed on only one of the two molded bodies.

[0008]

However, the above-described conventional configuration has the following problems. That is,
The resin injected from the nozzle tip has a quality deterioration problem in that the flow path is changed at right angles to the product part, whereby the flow speed is reduced and the birefringence characteristic is deteriorated.

After the resin is filled in the mold, the molded body and the sprue are cooled and solidified, the mold is opened, and when the molded body and the sprue are taken out from the mold by the take-out machine, the sprue is not sufficiently solidified. When the mold is opened in the middle, the sprue is torn off and separated, or the sprue remains in the mold. As a result, there is a problem that sprue take-out failure occurs, continuous production of the disk molded body is stopped, the operating rate is reduced, and the material yield is reduced.

[0010] Further, when the temperature of the center of the mold is lowered to cool the sprue quickly, there is a problem of deterioration in quality such that the birefringence characteristics deteriorate.

The present invention has been made in order to solve such problems, and provides a method and apparatus for manufacturing an optical disk, which achieves improvement in optical disk quality, improvement in yield, and reduction in manufacturing cost. The purpose is to:

[0012]

According to the present invention, a resin material is injected from the center of the optical disk substrate of one of the opposing molds to the other mold. The flow of the resin material immediately after is changed obtusely in the radial direction of the optical disk substrate.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The manufacture of an optical disk substrate according to an embodiment of the present invention will be described below with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals. In the following description, a type in which a recording portion is formed on both of the two molded bodies to be bonded is taken as an example, but the recording portion is formed on only one of the two sheets. The present embodiment is also applicable to types.

FIG. 1 shows an optical disk substrate manufacturing apparatus according to a first embodiment of the present invention. The basic configuration is the same as that of the above-described conventional apparatus, and the same reference numerals are given.

This optical disk substrate manufacturing apparatus differs from the conventional apparatus in that the eject rod 77 is formed obliquely from the nozzle tip to the disk product part. With such a structure, the resin injected from the nozzle tip can flow obliquely along the eject rod 77, and the fluidity of the resin is improved. As a result, the birefringence characteristics are improved, and the disc quality is improved. In addition, since the contact area between the sprue 66 and the eject rod 77 increases, the cooling effect of the sprue 66 increases. As a result, since the sprue 66 is sufficiently solidified, it is possible to prevent the sprue 66 from being taken out poorly, and it is possible to continuously produce a disk molded body, thereby improving the operation rate and the material yield.

FIG. 2 shows an optical disk substrate manufacturing apparatus according to a second embodiment of the present invention. The basic configuration is the same as that of the optical disk substrate manufacturing apparatus according to the above-described first embodiment. And have the same reference numerals.

The optical disk substrate manufacturing apparatus is different from the optical disk substrate manufacturing apparatus according to the first embodiment in that the movable die 2 and the movable die 2 are separated from the nozzle tip of the die 10 on the nozzle side to the product part. The point is that the taper is the same angle.
Thereby, the resin injected from the nozzle tip can flow obliquely along the eject rod 777,
The fluidity of the resin is improved. As a result, the birefringence characteristics are improved, and the disc quality is improved. Also, by increasing the contact area between the sprue 666 and the eject rod 777,
The cooling effect of the sprue 666 increases. As a result, since the sprue 666 is sufficiently solidified, it is possible to prevent the sprue 666 from being taken out poorly, and it is possible to continuously produce a disc molded body, thereby improving the operation rate and the material yield.

In FIGS. 1 and 2, a taper is used as a means for changing the flow direction at an obtuse angle. It goes without saying that it is good.

[0019]

As described above, according to the present invention, the resin material is injected from the center of the optical disk substrate of one of the opposing molds toward the other mold, and the flow of the resin material immediately after the injection is performed. Is changed obtusely in the radial direction of the optical disk substrate, thereby improving the flow of the resin and improving the birefringence characteristics.

Further, by providing a taper in the gap from the tip of the nozzle to the product, cooling of the sprue can be accelerated.

Furthermore, the flow of the resin is improved and the birefringence characteristics are improved by forming the taper of the same angle from the tip of the nozzle from which the resin of both the movable and fixed molds is injected to the product portion. Can be.

Therefore, the quality of the optical disk can be improved, the material yield can be improved, and the manufacturing cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view of an optical disk substrate manufacturing apparatus according to a first embodiment of the present invention.

FIG. 2 is a sectional view of an optical disk substrate manufacturing apparatus according to a second embodiment of the present invention;

FIG. 3 is a cross-sectional view of a conventional optical disk substrate manufacturing apparatus.

FIG. 4 is a diagram showing a state of a bonding step in manufacturing a conventional optical disc.

[Explanation of symbols]

 66 sprue 77 eject rod 666 sprue 777 eject rod

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4F202 AG19 AH79 AM32 CA11 CB01 CK02 5D121 DD05 DD18

Claims (3)

[Claims] 1. A method of manufacturing an optical disk substrate formed on a disk by injecting a resin material into a void portion in a mold, comprising: An optical disk substrate comprising: a step of injecting a resin material toward a mold of the type; and a step of changing a flow of the resin material immediately after the injection at an obtuse angle in a radial direction of the optical disk substrate. Manufacturing method. 2. An apparatus for manufacturing an optical disk substrate formed on a disk by injecting a resin material into a cavity in a mold, comprising: an opposing mold having a cavity inside; A means for injecting a resin material from one mold to the other mold at a center of the resin material and a resin material provided at the other mold at a position facing the means for injecting the resin material. An apparatus for manufacturing an optical disk substrate, comprising: a taper for changing a flow in a radial direction of the optical disk substrate. 3. The optical disk substrate manufacturing apparatus according to claim 2, wherein the taper has a taper at the same position as the taper provided at one of the molds at a position facing the taper.