JP2002240104A - Method and apparatus for molding optical disk substrate - Google Patents

Abstract

(57) [Summary] (with correction) [PROBLEMS] To enable molding while individually controlling the characteristics of optical disk substrates that are simultaneously molded in a single molding operation, and to achieve molding with good characteristics and multiple moldings. Provided are an optical disk substrate molding method and an apparatus for molding an optical disk substrate, which can mold an optical disk substrate having small characteristic variations between substrates. An optical disk substrate injection molding method for simultaneously molding a plurality of optical disk substrates by forming a plurality of cavities by clamping a fixed die and a plurality of movable dies is performed. Is not performed simultaneously for a plurality of cavities, but is performed only for the cavity farthest from the injection device first, and after this operation is completed, the cavity before one is injected and filled. The injection filling operation is performed one by one from the cavity immediately before and the cavity farthest from the injection device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding direction of an optical disk substrate and an apparatus for forming the same. Thus, the present invention is effective as a molding method and a molding apparatus of a molded article for which high demands are made.

[0002]

2. Description of the Related Art Various types of optical disks, such as a CD system, an MO system, and a DVD system, are used in read-only, write-once, and rewrite types. Substrates used for such optical discs are molded and produced by injection molding or injection compression molding using a resin mainly composed of polycarbonate from the viewpoint of production efficiency and cost. In all of these optical disc substrate molding methods, the cavity formed by closing the mold is filled with the molten material resin, and the molten resin is cooled and solidified in the mold until it reaches a temperature at which it can be removed from the mold. Then, it is formed into a predetermined substrate shape. In the cavity, a stamper in which information necessary for the optical disk is engraved as a pit row or a guide groove is set, and during the process from filling the above-described molten resin into the cavity and solidifying it,
The necessary information engraved on the stamper is transferred onto the optical disk substrate to be molded. Then, the optical disk substrate molded in the mold, after the cooling step in the mold is completed,
It is taken out of the mold and passed to the next process after molding.

However, the range of use of optical disks has expanded,
As a result, as the demand increases and the production volume increases, the demand for reducing the manufacturing cost of the optical disk also becomes strict, and attempts are being made to reduce the cost from various viewpoints.
In order to respond to such a reduction in manufacturing cost, it is effective to shorten the molding cycle and improve molding efficiency. Attempts to shorten the molding cycle have been made in various ways, both on the hardware side of the molding machine, the mold, and the removal device that takes the molded optical disk substrate out of the mold, and on the software side, such as setting the molding conditions. We are pushing the limits of the material properties of materials.

[0004] However, there is no limit to the demand for further reducing the manufacturing cost of the optical disk substrate, in other words, the demand for shortening the molding cycle. As one method to meet such a demand, the production of a large number of optical disk substrates has been studied. This is achieved by simultaneously molding a plurality of optical disc substrates by one molding operation (one cycle).
In an attempt to shorten the molding time per sheet, an injection molding apparatus having a configuration in which a plurality of cavities are arranged side by side in the same plane, that is, a configuration in which a plurality of dies are arranged side by side, has been used. It is common. However, in such an injection molding apparatus, since a plurality of cavities (dies) are arranged side by side, the projected area of the mold becomes large. )
The clamping force for closing the cavity (mold) must also be increased at the same time. In other words, a large-sized injection molding machine is required for multi-cavity molding of a molded substrate as described above. This leads to an increase in the introduction cost and the installation area of the molding machine, and is disadvantageous from the viewpoint of reducing the production cost.

As a method of forming an optical disk substrate by solving the above-mentioned problem, Japanese Patent Application Laid-Open No. 9-207171 discloses an "injection molding method for a molded article having an opening formed in the center and an injection molding apparatus therefor". This is the same as the prior art in that the apparatus configuration having a plurality of cavities and the simultaneous molding of a plurality of optical disc substrates by one molding operation are the same as in the prior art, but a plurality of cavities (die). Instead of arranging in the lateral direction, it has a so-called stacking mold configuration in which it is arranged in the mold clamping direction, and a configuration in which a central hole can be punched in the center of the substrate during the molding process. It is characterized by having.
Therefore, there is an advantage that a plurality of optical disk substrates can be simultaneously molded using an existing small-sized injection molding machine.

[0006]

2. Description of the Related Art The "injection molding method for molded articles having an opening at the center and the injection molding apparatus therefor" in Japanese Patent Application Laid-Open No. 9-207171 discloses a method for molding a molded article having an opening at the center. Not only is it possible to mold a plurality of molds at the same time, but it is also extremely excellent in that equipment costs can be reduced by using existing small injection molding machines, but this is actually an optical disk substrate, especially that substrate. There is a very large problem in applying to the molding of an optical disc substrate which has good characteristics itself and is required to keep the characteristic variation among a plurality of substrates small, for example, a DVD or an optical disc substrate for high density recording of DVD or more. Is left. This problem is that, when a plurality of cavities are filled with molten resin in a single molding operation to form a plurality of molded products, it is difficult to make characteristics between molded products molded in different cavities uniform. It is. In particular, in this molding method, since a plurality of cavities are arranged so as to overlap in the mold clamping direction instead of in the lateral direction, the resin filled in each cavity flows after flowing through a flow path having a different length between the cavities. Since the cavities are filled, it is extremely difficult to make the characteristics of a molded product molded between different cavities uniform.

To explain the above difficulties in more detail, when molding using N cavities by the above-described method, the first cavity located closest to the injection device side has a nozzle portion at the tip of the injection device. Is filled with the resin that has flowed through the normal sprue runner portion by being injected from the sprue runner. The second cavity disposed second from the injection device side is filled with a resin that has flown through the runner portion in the first intermediate gate cutter having the same length as the thickness of the first intermediate movable mold in addition to the sprue runner portion. Is done. The third cavity further includes a sprue runner and first and second cavities.
The resin that has flowed through the runner having a length that is equal to the thickness of the movable mold is filled. Thus, the n-th counting from the injection device side
The second cavity has a sprue runner section and (n-
1) The resin that has flown in the runner portion having the length obtained by adding the thickness of the intermediate movable mold for the individual pieces is filled. In addition, since all of the above filling operations are performed by a common injection device,
When the resin reaches the outermost peripheral end of the n-th cavity (filling is completed), the subsequent (n +
The (α) -th cavity is filled with the resin flowing through a longer path than the n-th cavity, so that the filling operation is incomplete, and the (n-α) -th cavity in the front is already filled. Is completed, while the injection device is still performing the filling operation, so that the filling pressure is excessively applied to the cavity, in other words, the resin is about to be excessively charged. As a result, for example, if the filling conditions of the injection device are set so that the characteristics of the molded product molded in the n-th cavity are the best, the resin in the cavity closer to the injection device than the cavity is more than the optimum condition. In the formed molded product and the cavity on the side of the mold clamping device, a molded product underfilled under the optimum condition can be obtained. Since these molded products are molded by filling the resin with settings different from the optimum conditions, the characteristics are naturally inferior to those of the molded products molded in the n-th cavity. Furthermore, since these molded products are molded under different filling conditions according to the distance from the optimal filling cavity at the cavity position where the molded product is molded, all molded products having mutually different molded product characteristics. Becomes That is, using the above method, N molded products obtained by one molding operation are:
All N will have different properties from each other.

When molding an optical disk substrate by the above method, obtaining a plurality of optical disk substrates by one molding operation is extremely effective in reducing manufacturing costs. However, the optical disk substrate is also required to strictly satisfy the characteristic specifications defined for the substrate characteristics at the same time. Particularly, in the case of a DVD or an optical disk substrate for high-density recording of DVD or higher, the allowable width of the above-mentioned characteristic specifications is also limited. It is set in a very narrow range. Therefore, the above-described molding method in which the characteristics of a molded product molded among a plurality of cavities are essentially varied is not an appropriate molding method in view of control of the quality of the molded product.

As a method of suppressing the characteristic variation among a plurality of molded products obtained by one molding operation, in a usual multi-cavity mold, a flow path in which a molten resin flows is branched in the mold and injected. Design the length of the resin flow path to each cavity so that all the resin flows from the device to each cavity by the same distance and fills it, and makes the state of resin flowing into each cavity uniform in all cavities For this reason, not only the flow path length of the resin flow path but also the flow path cross-sectional area has been taken into consideration for each cavity. Further, in a cavity into which resin does not easily flow due to a shape or the like, there is a method of performing a flow path design in which a plurality of inlets (gates) through which resin flows into the cavity and simultaneously completing the resin filling operation into all cavities. .

However, in the case of molding an optical disk substrate, if a weld line (a trace of the flowing state of the resin, which is particularly noticeable in a portion where resin flows in different directions collide with each other) is formed in the substrate, the weld line is formed. However, since this directly causes a signal failure of the optical disc, an inflow port (gate) through which the resin flows into the cavity is always provided at the center of the cavity, and the resin is uniformly distributed from the center of the cavity to the outer peripheral edge of the substrate (concentric circle). The resin flow path is designed to flow (so that it spreads like a circle). Therefore, as described above, in a so-called stack molding die in which a plurality of cavities are stacked in the mold clamping direction rather than in the lateral direction, the melt flow path is branched in the die, and the resin is completely injected from the injection device to each cavity. Either design the length of the resin flow path into each cavity so that it flows and fills by the same distance, or flow the resin flow path to make the resin flow into each cavity uniform in all cavities. By adopting a method that considers not only the path length but also the cross-sectional area of the flow path and the position and number of gates for each cavity, it is possible to suppress the characteristic variation among multiple molded products obtained in one molding operation. Therefore, it can be said that the mold structure is impossible.

[0011]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is extremely difficult in terms of a mold structure to suppress a characteristic variation among a plurality of molded products obtained by one molding operation. In an optical disk substrate molding apparatus using a so-called stack molding die, in which a plurality of cavities are arranged so as to overlap in a mold clamping direction instead of in a lateral direction, instead of performing a resin filling operation on a plurality of cavities at the same time, one operation is performed. By providing a molding apparatus configuration and molding method that can perform filling operations sequentially for each cavity, molding can be performed while individually controlling the characteristics of optical disk substrates that are simultaneously molded in a single molding operation. Optical disk substrate molding method and molding apparatus for molding an optical disk substrate having good characteristics and small variation in characteristics among a plurality of molded substrates It is an its object to devise.

[0012]

[Measures taken to solve the problem]

According to a first aspect of the present invention, there is provided a method of forming a plurality of optical disc substrates by simultaneously forming a plurality of cavities by clamping a fixed mold and a plurality of movable molds. In the optical disk substrate injection molding method, the operation of injecting and filling the molten resin into the cavities is not performed simultaneously on a plurality of cavities, but is performed only on the cavity farthest from the injection device at first, and this operation is completed. After that, the next cavity is injected and filled, and the next cavity and the cavity farthest from the injection device are sequentially injected and filled one by one, whereby a plurality of optical disc substrates can be simultaneously formed in one molding operation. In the case of molding as well, it is to perform an injection filling operation capable of individually controlling the characteristics of each molded substrate.

[0013]

According to a second aspect of the present invention, there is provided an optical disk substrate molding apparatus for performing molding by an optical disk substrate injection molding method according to the first aspect of the present invention, wherein while a certain cavity is being injected and filled with a molten resin, By providing a resin injection and filling control means for preventing the resin from flowing into other cavities, it is possible to prevent the injection and filling operation for one cavity from affecting the injection and filling operation for other cavities, The purpose of the present invention is to appropriately control the injection filling and the characteristics of the optical disk substrate to be molded in the cavity.

[0014]

According to a third aspect of the present invention, in the optical disk substrate molding apparatus of the second aspect, the filling of the molten resin into a certain cavity is completed and the operation of closing the gate of the cavity is performed. Then, by performing the operation of opening the gate of the cavity to be filled with the molten resin, by providing the molten resin injection and filling control means, the switching operation of the injection filling operation performed for each cavity, in a short time, The goal is to keep the entire molding cycle short.

[0015]

According to a fourth aspect of the present invention, in the optical disk substrate forming apparatus according to the second or third aspect, the mirror surface of the optical disk substrate is formed on both the injection device side and the mold clamping device side. For an intermediate movable mold having a stamper mirror surface for mounting a stamper for transferring information onto a cavity mirror surface or an optical disk substrate, a temperature control circuit for individually controlling the temperature of the two mirror surfaces of the one intermediate movable mold. By performing the optimum cavity temperature control for each cavity individually, the injection filling control and the control of the characteristics of the optical disk substrate to be molded are performed optimally for each cavity individually.

[0016]

According to a fifth aspect of the present invention, in the intermediate movable mold of the injection molding apparatus according to any one of the second to fourth aspects, the intermediate means is located at a central portion of the intermediate movable mold, and is provided on the injection device side. Close the gate of the cavity to form the center hole of the optical disc substrate, and separate each of the intermediate gate cutters with the runner for introducing the molten resin into the cavity on the mold clamping mechanism side. By providing a temperature control circuit for controlling the temperature of each intermediate gate cutter and controlling the temperature of the optimal runner portion individually for each intermediate gate cutter, the injection filling control for each cavity and the control of the characteristics of the optical disc substrate to be formed are optimally performed. At the same time, the cooling operation of the runner part is appropriately performed.

[0017]

According to a sixth aspect of the present invention, there is provided the optical disk substrate injection molding method according to the first aspect, wherein the optical disk substrate molding apparatus according to the second to fifth aspects is used.
When the mold is opened and the molded product is taken out after the cooling process is completed, first, the cavity closest to the injection device is opened, the optical disk substrate and the runner part are taken out, and then the cavities on the mold clamping mechanism side are sequentially taken out. An object of the present invention is to open the optical disk substrate and take out the optical disk substrate, so that the amount of mold opening required for the entire mold is suppressed to a small value, and the optical disk substrate can be molded by the molding method of the present invention using an existing small molding apparatus.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A method and apparatus for molding an optical disk substrate according to the present invention will be described in accordance with the procedure.
The embodiment described below has one intermediate movable mold and two intermediate movable molds.
Although a molding apparatus having two cavities has been described, a configuration having more intermediate movable molds and cavities can be explained by simply repeating the contents described in the present embodiment as it is. FIG. 1 shows a state in which the mold 1 of the molding apparatus 0 according to the present invention is opened. The mold is composed of a fixed mold 10, an intermediate movable mold 20, and a movable mold 30, and a molding device 0 is an injection device (not shown) on the left hand side of the fixed mold in addition to the illustrated mold 1. ) And a mold clamping device (not shown) on the right hand side of the movable mold 30. In the method of molding an optical disk substrate according to the present invention, first, the mold 1 is closed using a mold clamping device (not shown) of the molding device 0 (FIG. 2). Next, as shown in an enlarged view around the center of the mold in FIG. 3, the injection device (not shown) advances, and the nozzle 2 presses the sprue bush 11 of the fixed mold 10 at a predetermined nozzle touch pressure P1. The sprue bush 11 advances by a predetermined stroke when receiving the nozzle touch pressure equal to or higher than the pressure P2 smaller than the pressure P1, and returns when the nozzle touch pressure becomes equal to or lower than the predetermined pressure P2.
2 so as to retreat to the initial position, and to be slidable back and forth. Then, the sprue bush 11 pushed by the nozzle 2 advances as shown in FIG. 3 until the intermediate gate cutter 21 of the intermediate movable mold 20 is pressed against the sprue bush 11, and the sprue runner 13 in the sprue bush 11 and the intermediate in the intermediate gate cutter. The runner 22 is connected, and at the same time, the first gate 15 of the first cavity 14 formed between the fixed mold 10 and the intermediate movable mold 20 is closed. And nozzle 2
More molten resin (not shown) is injected and filled into the mold 1 through the sprue runner 13. At this time, since the first gate 15 is closed by the advancing sprue bush 11, the molten resin is filled in the first cavity 14. Does not flow, flows through the intermediate runner 22 and flows into the second cavity 31 formed between the intermediate movable mold 20 and the movable mold 30.

When the flow of the molten resin into the second cavity 31 and the filling thereof are completed and the injection and filling into the second cavity 31 are completed, as shown in FIG.
2 moves forward by a predetermined stroke to close the second gate 33 of the second cavity 31. At this time, the ejector pin 34 also advances by the same amount of advance in conjunction with the advance operation of the gate cutter 32, and closes the opening 23 on the second cavity side of the intermediate runner 22. Further, in conjunction with the above-described forward movement of the gate cutter 32, the nozzle touch pressure of the nozzle 2 is reduced to a predetermined pressure P3. The nozzle touching force P3 is high enough to keep the nozzle 2 and the sprue bush 11 pressed against the injection pressure for filling the molten resin into the mold 1, and the return spring 1 of the sprue bushing.
Due to the spring force of 2, the sprue bush 11 is set at a pressure low enough to retreat to the initial position. As a result, the nozzle 2 and the sprue bush 11 recede, and the first gate 1
5 is opened, and the molten resin starts flowing into the first cavity 14. At this time, since the second gate 33 of the second cavity 31 is already closed, the operation of filling the second cavity 31 by the operation of filling the first cavity 14 and the characteristics of the optical disk substrate formed by the second cavity are as follows. It is not affected.

When the injection and filling of the molten resin into the first cavity 14 is completed and the injection and filling of the molten resin into the first cavity 14 is completed, as shown in FIG.
2 is further advanced by a predetermined stroke, pushed by the intermediate gate cutter 21 to advance, closes the first gate 15, and the injection device (not shown) injects and fills the molten resin into the mold 1. Is completed. Also at this time, the ejector pin 34 advances by the same amount of advance in conjunction with the advance operation of the gate cutter 32, and maintains the state around the opening 23 on the second cavity side of the intermediate runner 22 as it is.
In the injection filling operation described above, since the individual injection filling operation is performed for each of the first and second cavities as described above, it is possible to perform the injection filling by setting the optimum conditions for each cavity. In addition, each filling operation does not affect the filling operation of the other cavity and the characteristics of the optical disk substrate to be formed. for that reason,
It is possible to improve the characteristics of the optical disk substrate formed by both cavities and to reduce the characteristic difference between the cavities. In addition, the time required for the injection filling operation is not different from the case of simultaneous injection filling for all cavities in the final filling amount of the molten resin and the injection rate of the molten resin in the injection device used in both methods. In addition, as for the operation of switching injection and filling between cavities, the gate closing of one cavity and the operation of opening the gate and starting injection and filling of the next cavity are performed in conjunction with each other as described above, and there is no time loss. Even when the injection filling operation is individually performed for a plurality of cavities as in the invention,
The injection filling time is not extended as compared with the case where all the cavities are injected and filled at the same time.

The operation of injecting and filling the molten resin into both the first and second cavities is completed by the above procedure, and the process proceeds to a cooling step of cooling the molten resin filled in the cavity for a predetermined time. Due to the effect of the mold clamping operation by the mold clamping device (not shown) of the molding device 0 mainly before and after the completion of the injection filling operation, necessary information engraved as pit rows or guide grooves on the stamper is printed on the molding substrate. Transcribed. In the above embodiment, the stampers 16 and 24
Are respectively provided on the mirror surfaces of the fixed mold 10 and the intermediate movable mold 20 on the mold clamping device side, with the inner peripheral portions of the stamper inner peripheral holder 17,
25, and the outer peripheral side is held and mounted by a vacuum suction method.

Further, in the present invention, the fixed mirror surface (stamper mirror surface) block 18 of the fixed mold 10, the intermediate movable mold 2
The temperature control circuit (not shown) for individually controlling the temperature of the mirror surface block 26, the stamper mirror surface block 27, and the mirror surface block 35 of the movable mold 30 is provided. During the entire process, the mirror side and the information side (stamper side) of the cavity in which all the optical disk substrates in the mold 1 are molded can be controlled at optimal temperature settings, and the optical disk to be molded There is an effect that the characteristics of the substrates can be improved, and at the same time, the variations in characteristics between the formed substrates can be suppressed.

Further, in the present invention, the sprue bush 11 and the gate cutter 32 which are generally used in the related art are used.
In addition to providing a temperature control circuit (not shown) on the intermediate gate cutter 21, a dedicated temperature control circuit (not shown) is also provided on the intermediate gate cutter 21 so that the intermediate runner 22 can be controlled at an optimum temperature. By adjusting the temperature and optimizing the injection filling operation of the molten resin into the second cavity 31 and the cooling operation before and after the intermediate runner 22 during the cooling step,
In addition to improving the characteristics of the optical disk substrate to be molded, it is possible to stably and reliably open the mold after completion of the cooling step and take out the molded optical disk substrate / runner.

After the molten resin filled in the cavity is cooled in the mold for a predetermined cooling time, the molding machine
The mold is opened by the mold clamping device (not shown). At this time, in the present invention, as shown in FIG. 6, first, the intermediate movable mold 20 and the movable mold 30 are kept closed by the intermediate movable mold opening / closing mechanism 4 provided on the coupling sleeve 3 of the mold 1. ,
Only the first cavity between the fixed mold 10 and the intermediate movable mold 20 is opened. At the time of the mold opening operation, the sprue bush 11 of the fixed mold 10 and the inner peripheral holder 1 of the stamper are used.
A mold release air blow is blown out from an air slit (not shown) between the molds 7 to release the molded optical disk substrate 5 from the fixed mold 10 and to support it on the intermediate movable mold 20 side. At the same time, the runner 6 in which the resin filled in the sprue runner 13 and the intermediate runner 22 are integrated and solidified is also supported by the intermediate movable mold 20 side.

Subsequently, as shown in FIG. 7, the release air blown from an air slit (not shown) between the intermediate gate cutter 21 and the first ejector sleeve 28 and the first release air.
By ejecting the ejector sleeve 28, the optical disk substrate 5 is released from the intermediate movable mold 20 as well.
Ejector pin 3 for ejecting operation at the same time
The runner 6 is also released from the intermediate movable mold 20 by 4. Then, the optical disk substrate 5 and the runner 6, which have been released from the intermediate movable mold 20, are taken out of the molding apparatus by a molded article take-out apparatus (not shown) and are put into subsequent steps. When the removal of the molded product from the first cavity 14 is completed, the first ejector sleeve 28 and the ejector pin 34 are retracted to the initial position as shown in FIG. 20 moves to the injection device (not shown) side to open the second cavity 31, and further moves to the fixed mold 10 to form the first cavity 14. During this operation, an air slit (not shown) between the stamper inner peripheral holder 25 of the intermediate movable mold 20 and the intermediate gate cutter 21.
Is released from the mold, the optical disk substrate 7 formed in the second cavity 31 is released from the intermediate movable mold 20 and is supported on the movable mold 30 side. Also, an intermediate gate cutter 21 and a gate cutter 32 punched to form a center hole of the optical disc substrate 7.
Punched piece 8 in which resin filled in the portion between
Is supported at the tip of the gate cutter 32 by an inverted taper portion provided in the slag reservoir 36 at the tip of the gate cutter 32.

Subsequently, as shown in FIG. 9, the optical disk substrate 7 is released by the release air blown from an air slit (not shown) between the gate cutter 22 and the second ejector sleeve 37 and the operation of projecting the second ejector sleeve 37. The mold is also released from the movable mold 30. Also the second
The ejector sleeve 37 has a mechanism for simultaneously projecting the punched pieces 8 supported by the slag reservoir 36 together with the optical disk substrate 7, and the punched pieces 8 are also released from the movable mold 30. Then, the optical disk substrate 7 released from the movable mold 30 is taken out of the molding device by a molded product take-out device (not shown), and is put into subsequent steps. At this time, the punched piece 8 falls and is discharged as it is.

In the procedure of opening the mold and removing the molded product in the procedure according to the present invention, the molded product formed by the plurality of cavities arranged in the mold opening / closing direction is not removed simultaneously with opening all the cavities at the same time. Since the operations of taking out the molded products one by one after being opened one by one are performed, it is possible to reduce the amount of mold opening required as a whole mold, and it is possible to utilize existing small molding equipment. . Then, after performing the mold opening to the molded product removal operation according to the above-described procedure, the movable mold 30 is moved to the injection device (not shown) by the mold clamping device (not shown) of the molding device 0.
Then, the entire mold 1 is closed (FIG. 2), and the molding operation of the next cycle is performed.

[0028]

The operation and effect of the present invention are summarized as follows for each claim. 1. The invention according to claim 1, wherein in the optical disk substrate injection molding method for performing molding by overlapping a fixed die and a plurality of movable dies to form a plurality of cavities to simultaneously mold a plurality of optical disk substrates, The operation of injecting and filling the molten resin into the cavity at the farthest position from the injection device is performed first, instead of simultaneously performing the operations of multiple cavities. In the case where a plurality of optical disc substrates are simultaneously molded by one molding operation, each molding is performed by sequentially performing the injection filling operation one by one from the cavity farthest before and the cavity farthest from the injection device. Injection and filling operations that can individually control the substrate characteristics provide good characteristics and small variations in characteristics between substrates. An optical disk substrate can be manufactured.

2. According to the second aspect of the present invention, in the optical disk substrate molding apparatus according to the first aspect of the present invention, the resin is prevented from flowing into another cavity while the molten resin is being injected and filled into one cavity. Since the injection filling control means for the molten resin is provided, it is possible to prevent the injection filling operation to one cavity from affecting the injection filling operation to the other cavities, and to control the injection filling operation for each cavity. It is possible to appropriately control the characteristics of the optical disk substrate to be molded.

3. According to the third aspect of the present invention, in the optical disk substrate molding apparatus of the second aspect, the filling of the molten resin into one cavity is completed, and the molten resin is filled next in conjunction with the operation of closing the gate of the cavity. Since the apparatus is provided with a molten resin injection filling control means for opening the gate of the cavity, the switching operation of the injection filling operation performed for each cavity can be performed in a short time, and the entire molding cycle can be shortened. .

4. According to the fourth aspect of the present invention, in the optical disk substrate molding apparatus according to the second or third aspect, information is transferred onto a cavity mirror surface or an optical disk substrate that forms a mirror surface of the optical disk substrate on both the injection device side and the mold clamping device side. For an intermediate movable mold having a stamper mirror surface to which a stamper to be mounted is provided, a temperature control circuit is provided for individually controlling the temperature of two mirror surfaces of one intermediate movable mold, and an optimal cavity temperature control is individually performed for each cavity. Therefore, it is possible to optimally perform the injection filling control and the control of the characteristics of the optical disk substrate to be molded individually for each cavity.

5. According to a fifth aspect of the present invention, in the intermediate movable mold of the injection molding apparatus according to any one of the first to fourth aspects, the gate of the cavity at the center of the intermediate movable mold on the side of the injection device is closed to close the optical disk substrate. A temperature control circuit for individually controlling the temperature of each of the intermediate gate cutters is provided for the intermediate gate cutters having a center hole formed therein and a runner for introducing the molten resin into the cavity on the mold clamping mechanism side. Equipped,
Since the optimal temperature control of the runner part is performed individually for each intermediate gate cutter, the injection filling control performed individually for each cavity and the characteristic control of the optical disc substrate to be formed are optimized, and the cooling operation of the runner part is appropriately performed. It can be carried out.

6. According to the invention of claim 6, in the optical disk substrate injection molding method of claim 1 using the optical disk substrate molding apparatus of claims 2 to 5, when the mold is opened and the molded product is taken out after the cooling step is completed. First, the cavity closest to the injection device is opened, and the optical disk substrate and the runner portion are taken out. Subsequently, the cavity on the mold clamping mechanism side is opened and the optical disk substrate is taken out. The required amount of mold opening can be kept small, and the optical disk substrate can be formed by the forming method of the present invention using an existing small-sized forming apparatus.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a state in which a mold 1 of a molding apparatus according to an embodiment is opened.

FIG. 2 is a cross-sectional view showing a state in which a mold is closed using a mold clamping device of the molding device of the embodiment.

FIG. 3 is an enlarged sectional view of a part of FIG. 2;

FIG. 4 is a cross-sectional view showing a state in which a gate cutter of a mold of the molding apparatus according to the embodiment advances by a predetermined stroke to close a second gate of a second cavity.

FIG. 5 shows that the gate cutter of the mold of the molding apparatus of the embodiment advances by a predetermined stroke, the intermediate gate cutter advances, closes the first gate 15, the ejector pin advances, and the intermediate runner moves forward. It is sectional drawing which shows the state which has hold | maintained the state of the opening part periphery on the 2 cavity side as it is.

FIG. 6 is a view showing a state in which the intermediate movable mold and the movable mold are closed by an intermediate movable mold opening / closing mechanism provided on a coupling sleeve of the mold of the molding apparatus according to the embodiment, and the fixed mold and the intermediate movable mold are held together. It is sectional drawing which shows the state which only the 1st cavity between the dies opened.

FIG. 7 is a cross-sectional view showing a state in which the optical disc substrate is released from the intermediate movable mold in the mold of the molding apparatus according to the embodiment.

FIG. 8 is a cross-sectional view showing a state in which the intermediate movable mold is moved to the injection device side by the intermediate movable mold opening / closing mechanism and the second cavity is opened in the mold of the molding apparatus according to the embodiment. .

FIG. 9 is a cross-sectional view showing a state in which the optical disk substrate is released from the movable die by a protrusion operation of the second ejector sleeve or the like in the die of the molding apparatus according to the embodiment.

[Explanation of symbols]

 0: molding apparatus 1: mold 2: nozzle 5, 7: optical disk substrate 6: runner 10: fixed mold 11: sprue bush 12: spring 13: sprue runner 14: first cavity 15: first gate 16, 24: Stampers 17, 25: Stamper inner peripheral holder 18: Fixed mirror surface block 20: Intermediate movable mold 21: Intermediate gate cutter 22: Intermediate runner 23: Opening on the second cavity side 25: Stamper inner peripheral holder 26, 35: Mirror surface block 28: 1st ejector sleeve 30: Working mold 31: To 2nd cavity 32: Gate cutter 33: 2nd gate 34: Ejector pin 37: 2nd ejector sleeve

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4F202 AG19 AH79 AR06 CA11 CB01 CK03 CK06 CK07 CK43 CL01 CL06 CL09 4F206 AG19 AH79 AR064 JA07 JL02 JM04 JN12 JN15 JN17 JN32 JQ81 JQ83 5D121 AA02 DD05 DD17 DD20

Claims (6)

[Claims] In an optical disk substrate injection molding method, a fixed die and a plurality of movable dies are overlapped to form a plurality of cavities to simultaneously form a plurality of optical disk substrates. Is performed only on the cavity farthest from the injection device first, and after this operation is completed, the cavity is injected and filled into the immediately preceding cavity, and then the cavity immediately before and An injection molding method for an optical disk substrate, comprising sequentially performing an injection filling operation one by one from a cavity far from an injection device. 2. An optical disk substrate molding apparatus according to claim 1, wherein the resin is prevented from flowing into another cavity while injection molding and filling of the molten resin into one cavity.
An optical disk substrate molding apparatus, comprising: means for controlling filling of molten resin. 3. The optical disk substrate molding apparatus according to claim 2, wherein the filling of the molten resin into one cavity is completed, and the cavity to be filled with the molten resin next is linked with the operation of closing the gate of the cavity. An optical disk substrate molding apparatus, comprising: a molten resin filling control means for performing an operation of opening a gate to a substrate. 4. An optical disk substrate molding apparatus according to claim 2, wherein information is transferred onto a cavity mirror surface for forming a mirror surface of the optical disk substrate on both the injection device side and the mold clamping device side, or onto the optical disk substrate. An optical disk substrate forming apparatus, comprising: a temperature control circuit for individually controlling the temperatures of two mirror surfaces of the intermediate movable mold with respect to an intermediate movable mold having a stamper mirror surface for mounting a stamper. 5. The intermediate movable mold of the injection molding apparatus according to claim 2, wherein a center hole of the cavity on the side of the injection apparatus is closed by closing a gate of the cavity on the injection apparatus side. And a temperature control circuit for individually controlling the temperature of each of the intermediate gate cutters provided with a runner for introducing the molten resin into the cavity on the mold clamping mechanism side. An optical disk substrate molding apparatus, comprising: 6. The optical disk substrate injection molding method according to claim 1, wherein the optical disk substrate molding apparatus uses the optical disk substrate molding apparatus according to any one of claims 2 to 5, when the mold is opened to take out a molded product after the cooling step is completed. An optical disk substrate molding method, comprising: opening a cavity closest to an injection device, extracting an optical disk substrate and a runner portion, and then sequentially opening a cavity on a mold clamping mechanism side and extracting an optical disk substrate.