JP2006007690A - Disk molding mold - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a disk molding mold which improves the transfer rate of the peripheral part without increasing the temperature of the interior part of an optical disk and production efficiency by suppressing the occurrence of the deformation of a pit or a groove and shortening a molding cycle. <P>SOLUTION: The disk molding mold 100 is composed of a movable mold 5 and a fixed mold 3, and an optical disk molding is molded by injecting a resin material into a void part 13 formed in the mold 100. In the mold 3 fitted with a stamper 11 having the information recording groove, an empty layer 83 is formed between a mold mirror surface 3d in contact with the peripheral part of the stamper 11 and a mold temperature adjusting piping path 25. Hot air heated at a prescribed temperature is supplied to the empty layer 83 as required to raise the temperature of the peripheral part of the disk to be higher than the temperature of the interior part of the disk. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a disk molding die, and more particularly to a disk molding die capable of molding an optical disk having excellent optical characteristics.

  In general, an optical disk (molded substrate) is molded by injecting a molten thermoplastic resin into a gap formed in a mold and then cooling it in the mold. FIG. 4 is an enlarged view of a main part of such an optical disk molding die. As shown in FIG. 4, the optical disc molding die 1 includes a fixed die 3 and a movable die 5. The fixed die 3 is supported so as not to move, and the movable die 5 is a fixed die 3. Are arranged so as to be freely connected to each other (movable in the vertical direction in FIG. 4).

  The fixed mold 3 includes a fixed-side positioning member 7 on the outer peripheral portion, and a nozzle 9 provided with a nozzle hole 9a for injecting a resin material at the center. A barrel (not shown) for supplying a molten thermoplastic resin is connected to the nozzle 9. A stamper 11, which is an information master with an information recording groove formed thereon, is fixed to the mirror surface 3 a of the fixed mold 3 so as to constitute a part of the gap portion 13. More specifically, the inner peripheral portion of the stamper 11 is fixed by a stamper holder 15, and the outer peripheral portion of the stamper 11 is a vacuum such as a vacuum pump connected to a pipe line 3 b formed in the fixed mold 3. The air between the mirror surface 3a and the stamper 11 is sucked by the supply source 21 and adsorbed on the mirror surface 3a.

  The movable mold 5 includes a movable-side positioning member 23 on the outer peripheral portion, and a punch 25 is provided in the center portion. When the movable mold 5 is moved and joined to the fixed mold 3, the movable side positioning member 23 of the movable mold 5 and the fixed side positioning member 7 of the fixed mold 3 are fitted to each other, and the fixed mold 3. The relative position of the movable mold 5 is determined, and a gap (cavity) 13 is formed to face the stamper 11. Further, in the optical disc molding die 1, for example, spiral flow paths 25 and 27 in which a coolant is circulated are formed inside the fixed mold 3 and the movable mold 5, respectively. 27 is connected to a temperature controller (not shown) for circulating the refrigerant.

  The optical disc (molded substrate) is molded by the optical disc molding die 1 by a resin material (not shown) melted from the nozzle hole 9a in the cavity 13 formed by joining the movable die 5 to the fixed die 3 integrally. The resin material injected into the cavity 13 is forcibly cooled by the refrigerant together with the optical disc molding die 1. Then, after the resin material is solidified by cooling, the movable mold 5 is opened apart from the fixed mold 3 and the optical disk molded product is taken out.

  In the above-described molding of the optical disk (molded substrate), the resin temperature is preferably higher than the solidification temperature of the resin during injection filling and lower than the temperature at which it can be taken out during solidification. That is, when the resin material temperature is higher than the solidification temperature, the resin fluidity in the cavity 13 is high, so that the transfer property to the stamper 11 is improved, and a pit shape close to the unevenness of the stamper 11 is obtained. The optical disk characteristics such as rate are improved. Further, if the resin material temperature is not lower than the solidification temperature at the time of taking out, the optical disc (molded substrate) is deformed when taken out, warping occurs, and the optical disc characteristics deteriorate.

In addition, in order to obtain an optical disk with less distortion that causes a trace error when reading information and a decrease in C / N, the cooling rate of the resin material injected and filled in the cavity 13 is the same over the entire surface of the optical disk. Desirably, as such a disk molding die, between the heating means provided in the fixed die and the movable die, and the cooling means provided in the spool bush and the punch core for cooling the spool, It is known that a heating means is provided so that cooling of the central portion of the optical disk by the cooling means is suppressed so that the cooling rate of the optical disk is substantially the same over the entire surface. (For example, refer to Patent Document 1).
JP-A-5-221767

  As shown in the photograph of the temperature distribution measured by the infrared sensor in FIG. 5, in the molding of the optical disc by the conventional optical disc molding die 1 shown in FIG. 4, the molten resin at the time of injection filling is cooled from the contact portion with the cavity 13. Since the solidified layer develops and the inner peripheral portion is directly affected by the high temperature resin injected and filled into the cavity 13, a temperature difference occurs between the inner peripheral portion and the outer peripheral portion of the optical disc, and the temperature of the outer peripheral portion c is increased. (For example, 114.9 ° C.) tends to be lower than the temperature of the inner peripheral portion a (for example, 119.6 ° C.). For this reason, the transfer rate of grooves (grooves) and pits of the stamper 11 at the outer peripheral portion is lowered. Here, the temperature of the middle peripheral part b located between the outer peripheral part c and the inner peripheral part a is 117.0 ° C.

  FIG. 6 shows the relationship between the distance (Radius) from the center of the optical disc and the transferred groove depth (I). The groove depth up to about 47 mm from the center is approximately 160 nm. However, the groove depth gradually becomes shallower at the outer peripheral portion and decreases to about 100 nm at the outermost peripheral portion. That is, it can be seen that the transfer rate at the outer peripheral portion of the optical disk is lowered.

  Although it is possible to improve the transfer rate at the outer peripheral part by setting the mold temperature higher than the conventional temperature and improving the fluidity of the resin, according to this, the temperature of the inner peripheral part is more than necessary. However, it takes a long time to cool until the temperature of the inner peripheral portion becomes equal to or lower than the solidification temperature required for mold opening, and there is a problem that the production cycle is prolonged and the production efficiency is lowered. Further, since the temperature of the inner peripheral portion is high, the shape of the pits and grooves is deformed when the optical disc is taken out, and the inner peripheral portion cloud is likely to be generated, and the optical disc characteristics may be deteriorated.

  Further, according to the disk molding die disclosed in Patent Document 1, since the molten resin at the time of injection filling is cooled from the contact portion with the cavity, the outer peripheral portion of the optical disc having a lower temperature than the inner peripheral portion of the optical disc. Accordingly, the temperature of the entire surface of the optical disc is made substantially the same. In other words, since the molding is performed with the temperature of the entire surface of the optical disk being low, the transfer rate of pits and grooves may be reduced.

  The present invention has been made in view of the above circumstances, and it is possible to improve the transfer rate of the outer peripheral portion without increasing the temperature of the inner peripheral portion of the optical disc, to prevent deformation of pits and grooves, and to form a molding cycle. An object of the present invention is to provide a disk molding die that can be shortened to improve production efficiency.

  The disc molding die of the present invention is a disc molding die that is composed of at least two molds, and that molds an optical disk molded product by injecting a resin material into a gap formed in the mold. In the mold on the side to which the stamper having the recording groove is attached, a space layer is provided between the mold mirror surface in contact with the outer periphery of the stamper and the mold temperature control piping.

  According to the above configuration, in the mold on the side where the stamper having the information recording groove is attached, the space layer is provided between the mold mirror surface that is in contact with the outer peripheral portion of the stamper and the mold temperature control piping. The space layer acts as a heat insulating layer, and heat is stored on the stamper outer peripheral side of the mold. Therefore, the temperature of the outer periphery of the disk can be maintained higher than the temperature of the inner periphery without increasing the temperature of the inner periphery of the disk. As a result, the transfer rate of the outer peripheral portion of the disk is improved to obtain a pit shape close to the uneven shape of the stamper, and the optical disk characteristics such as birefringence and reflectance are improved.

  The disc molding die according to the present invention includes one provided with hot air supply means for supplying hot air heated to a predetermined temperature to the space layer.

  According to the above configuration, since the hot air heated to a predetermined temperature can be supplied to the space layer, the mold temperature of the outer peripheral portion of the disk can be further increased, thereby transferring the outer peripheral portion of the disk. The rate can be further improved.

  The disk molding die of the present invention includes air heating means for heating the temperature of the compressed air to a predetermined constant temperature by flowing the compressed air through a temperature-controlled pipe, and the air heating means has a predetermined constant temperature. The compressed air heated to a temperature is supplied to the space layer.

  According to the above configuration, the air heating means for heating the temperature of the compressed air to a predetermined constant temperature by flowing the compressed air through the temperature-controlled pipe is heated to the predetermined constant temperature by the air heating device. Since compressed air is supplied to the space layer, the temperature of the mold mirror surface with which the outer periphery of the stamper contacts can be stably controlled to an arbitrary temperature. As a result, the temperature at the outer periphery of the disk can be raised to substantially the same temperature as that at the inner periphery, and the temperature difference between the inner periphery and the outer periphery of the disk can be reduced. Accordingly, the optical disk characteristics can be improved by improving the transfer rate of the outer peripheral portion without lengthening the molding cycle.

  The disk molding die of the present invention includes one in which the air heating means includes a flow rate adjusting mechanism, and the flow rate of the compressed air supplied to the space layer is adjusted by the flow rate adjusting mechanism.

  According to the above configuration, the air heating means includes the flow rate adjusting mechanism, and the flow rate of the compressed air supplied to the space layer is adjusted by the flow rate adjusting mechanism, so that the temperature of the mold mirror surface with which the outer periphery of the stamper contacts is adjusted. Control can be performed more easily. As a result, the transfer rate of the disk can be improved and the molding cycle can be shortened easily.

  According to the disk molding die of the present invention, a space layer is provided between the mold mirror surface that is in contact with the outer peripheral portion of the stamper and the mold temperature adjusting piping, and hot air heated to a predetermined temperature is further applied to the space layer. Since it is supplied, it is possible to maintain the temperature of the outer periphery of the disk at a temperature higher than or substantially the same as the temperature of the inner periphery without increasing the temperature of the inner periphery of the disk. Thus, an optical disc having excellent optical disc characteristics can be formed by improving the transfer rate of the outer peripheral portion of the disc without increasing the molding cycle time. Further, the occurrence of deformation of pits and grooves can be reduced by controlling the temperature difference between the outer peripheral portion and the inner peripheral portion of the disk to a minimum.

  The present invention has been briefly described above. Furthermore, the details of the present invention will be further clarified by reading through the best mode for carrying out the invention described below with reference to the accompanying drawings.

  Embodiments according to the present invention will be described below in detail with reference to the drawings.

(First embodiment)
FIG. 1 is a schematic configuration diagram of a pre-plastic injection molding machine to which a disc molding die of the present invention is applied, and FIG. 2 is a longitudinal sectional view of an essential part of the disc molding die of the first embodiment.

  The injection molding machine of the present invention is formed in a substantially donut disk shape between the mirror surface 3a corresponding to the disk outer periphery of the fixed mold 3 in the disk molding mold 100 and the mold temperature adjusting piping 25. First, an injection molding machine will be described with reference to FIG. 1, which is characterized by having a space layer 83 (see FIG. 2). The injection molding machine 50 includes a cylinder 51, a barrel 53, and a disk molding die 100 according to the present invention. The cylinder 51 is for injecting a molten resin material into the cavity (gap) 13 of the disk molding die 100. A nozzle 55 serving as a resin injection port is provided at the tip (lower end in FIG. 1). The plunger 59 is accommodated in the internal cylinder chamber 57 so as to be movable in the axial direction. The lower part of the cylinder chamber 57 serves as a storage part for temporarily storing the resin material supplied from the barrel 53 side.

  At the upper end of the plunger 59, a load cell 61 for detecting the magnitude of the force acting on the plunger 59 and a slider 63 having a female screw portion (not shown) are disposed. The slider 63 is integrally attached to the plunger 59 via the connecting member 65. The internal thread portion of the slider 63 is screwed into a ball screw 69 fixed to the rotation shaft of the servo motor 67, and the plunger 59 is moved in the vertical direction by rotating the ball screw 69. The slider 63 has a guide hole (not shown) formed in the connecting member 65 slidably fitted on two guide pins 73 installed between the cylinder 51 and the base 71. The movement of the slider 63 in the rotational direction is limited. The servo motor 67 is provided with an encoder 75 for detecting the rotation speed and rotation angle of the rotation shaft of the servo motor 67.

  The control device 77 is electrically connected to the servo motor 67, the encoder 75, and the load cell 61. The rotation speed and rotation angle of the rotation shaft of the servo motor 67 detected by the encoder 75, and the plunger 59 detected by the load cell 61. A detection signal such as the magnitude of the force acting on the servo motor 67 is input, and a control signal based on the detection signal is output to the servo motor 67 to control the servo motor 67. That is, the control device 77 drives and controls the servo motor 67 so that the output torque of the servo motor 67 and the resin pressure in the storage portion of the cylinder chamber 57 detected by the load cell 61 become predetermined values.

  The barrel 53 has a supply port 79a communicating with the cylinder chamber 57 at one end (the right end in FIG. 1), and a screw chamber 79 for rotatably housing a screw 81 therein. A heating device (not shown) such as an electric heater for melting the resin material is wound around the outer peripheral surface of the screw chamber 79. The barrel 53 is provided with a hopper (not shown), and a resin material is put into the screw chamber 79 from the hopper. Then, by rotating the screw 81, the resin material charged into the screw chamber 79 from the hopper and melted by the heating device is supplied to the cylinder chamber 57 through the supply port 79a.

  The disc molding die 100 is composed of a fixed die (upper die) 3 and a movable die (lower die) 5, and when the die is clamped, an optical disk is formed by the fixed die 3 and the movable die 5. A cavity (gap part) 13 is formed. A gate 3 c that communicates with the cavity 13 is formed in the fixed mold 3, and the nozzle 55 of the cylinder 51 is disposed so as to communicate with the gate 3 c.

  Next, the disk molding die 100 will be described with reference to FIG. In the following embodiments, the basic configuration and basic operation of the disk molding die 100 are the same as those of the disk molding die 1 already described with reference to FIG. Detailed description will be omitted.

  As shown in FIG. 2, the disc molding die 100 is configured such that a stamper 11, which is an information master having an information recording groove formed on the mirror surface 3 a of the fixed die 3, constitutes a part of the gap portion 13. It is fixed. That is, the inner peripheral portion of the stamper 11 is fixed by the stamper holder 15, and the outer peripheral portion of the stamper 11 is mirrored by the vacuum supply source 21 connected to the conduit 3 b formed in the fixed mold 3. And the stamper 11 are sucked and fixed to the mirror surface 3a. A space layer 83 formed in a substantially donut disk shape is provided between a portion 3d of the mirror surface 3a that is in contact with the outer periphery of the stamper and the pipe 25 for mold temperature adjustment.

  The optical disk is molded by the disk molding die 100 according to the present embodiment. The movable die 5 is integrally joined to the fixed die 3 to form the cavity 13, the servo motor 67 is rotated, the plunger 59 is moved, and the nozzle is moved. A molten resin material (not shown) is injected into the cavity 13 from the hole 9a. Then, the resin material injected into the cavity 13 is forcibly cooled together with the disk molding die 100 by the refrigerant flowing through the mold temperature adjusting piping 25. After solidifying the resin material by cooling, the movable mold 5 is separated from the fixed mold 3 and the resin material adhering to the surface of the fixed mold 3 is peeled off by air blow (not shown) from the center of the mold 100. Thus, an optical disk molded product as a solidified resin material is obtained.

  Since the resin material injected into the cavity 13 is cooled from the contact portion with the cavity 13 and a solidified layer develops, and the inner peripheral portion is directly affected by the high-temperature resin injected and filled into the cavity 13, the optical disk A temperature difference occurs between the inner peripheral portion and the outer peripheral portion, and the temperature of the outer peripheral portion tends to be lower than the temperature of the inner peripheral portion. Since the space layer 83 is provided between the contacting portion 3d and the mold temperature adjusting pipe 25, the space layer 83 acts as a heat insulating layer, and the heat is in the vicinity of the portion 3d where the stamper outer peripheral portion of the mirror surface 3a is in contact. Thus, the temperature drop at the outer periphery of the stamper is suppressed. Therefore, the temperature of the outer peripheral portion of the disk can be maintained at a temperature higher than the temperature of the inner peripheral portion, thereby greatly improving the transfer rate of the outer peripheral portion of the disk.

  According to the disk molding die 100 of the present embodiment, in the die 3 on the side where the stamper 11 having the information recording groove is attached, the die mirror surface 3a with which the outer periphery of the stamper 11 contacts and the die temperature control piping Since the space layer 83 is provided between the layers 25, the space layer 83 acts as a heat insulating layer and stores heat on the stamper outer peripheral side of the mold 3. Therefore, the temperature of the outer periphery of the disk can be maintained higher than the temperature of the inner periphery without increasing the temperature of the inner periphery of the disk. Thereby, the transfer rate of the outer peripheral part of the disc is improved, and a pit shape close to the unevenness of the stamper 11 is obtained, and the optical disc characteristics such as birefringence and reflectance can be improved.

(Second Embodiment)
Next, a second embodiment of the disk molding die of the present invention will be described with reference to FIG. FIG. 3 is a schematic configuration diagram of a disk molding die according to the second embodiment of the present invention.
The disc molding die 200 according to the second embodiment has many common points with the disc molding die 100 according to the first embodiment, except that an air heating device 91 that supplies hot air to the space layer 83 is arranged. Since only the points are provided, the same parts are denoted by the same or corresponding reference numerals, and the description will be simplified or omitted.

  As shown in FIG. 3, the disk molding die 200 of the second embodiment includes an air heating device 91. The air heating device 91 controls the pipe 93 formed in a pipe shape with metal or the like, the heater 95 wound around the outer peripheral surface of the pipe 93, and the energization amount to the heater 95. And a temperature adjuster 97 that controls the temperature of the pipe line 93 to an arbitrary temperature. An upstream end portion 93 a of the conduit 93 is connected to a compressed air supply device (not shown) through a flow rate adjusting mechanism 99 by a pipe 111. The downstream end 93 b of the conduit 93 is connected to the space layer 83 by a pipe 113.

  Then, the compressed air is supplied from the compressed air supply device into the pipe line 93 heated to an arbitrary predetermined temperature by being controlled by the temperature regulator 97 and heated to the predetermined temperature, and then the heated compressed air is heated. Is supplied to the space layer 83 through the pipe 113. As a result, the temperature of the mirror surface 3d corresponding to the outer peripheral portion of the disk of the fixed mold 3 is increased to at least the same temperature as the inner peripheral surface of the disk to improve the transfer rate of the outer peripheral portion of the disk. Note that the temperature and supply amount of the compressed air supplied to the space layer 83 can be arbitrarily adjusted by the temperature adjuster 97 and the flow rate adjusting mechanism 99, whereby the mirror corresponding to the outer peripheral portion of the disk of the fixed mold 3. The temperature of the surface 3d can be controlled to an arbitrary temperature.

  According to the disk molding die 200 of the present embodiment, since the hot air heated to an arbitrary predetermined temperature is supplied to the space layer 83, the mold temperature of the outer peripheral portion of the disk can be increased, Thereby, the transfer rate of the outer periphery of the disk can be improved.

  Moreover, according to the disk molding die 200 of the present embodiment, the air heating device 91 that heats the temperature of the compressed air to a predetermined constant temperature by flowing the compressed air through the temperature-controlled pipe line 93 is provided. Since the compressed air heated to a predetermined constant temperature by the heating device 91 is supplied to the space layer 83, the temperature of the mold mirror surface 3d with which the outer peripheral portion of the stamper 11 contacts is stably controlled to an arbitrary temperature. be able to. As a result, the temperature at the outer periphery of the disk can be raised to substantially the same temperature as that at the inner periphery, and the temperature difference between the inner periphery and the outer periphery of the disk can be reduced. Accordingly, the optical disk characteristics can be improved by improving the transfer rate of the outer peripheral portion without lengthening the molding cycle.

  Furthermore, according to the disk molding die 200 of the present embodiment, the air heating device 91 includes the flow rate adjusting mechanism 99, and the flow rate adjusting mechanism 99 adjusts the flow rate of the compressed air supplied to the space layer 83. The temperature of the mold mirror surface 3d with which the outer periphery of the stamper 11 is in contact can be more easily controlled. As a result, the transfer rate of the outer periphery of the disk can be improved and the molding cycle can be shortened.

  In addition, this invention is not limited to embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably. In addition, the material, shape, dimension, numerical value, form, number, arrangement location, and the like of each component in the above-described embodiment are arbitrary and are not limited as long as the present invention can be achieved.

1 is a schematic configuration diagram of a pre-plastic injection molding machine to which a disc molding die of the present invention is applied. It is a principal part longitudinal cross-sectional view of the disk shaping die of 1st Embodiment of this invention. It is a schematic block diagram of the disk shaping die which is 2nd Embodiment of this invention. It is a principal part longitudinal cross-sectional view of the conventional disk shaping die. It is a photograph which shows the temperature distribution just before disc taking-out of the disc shape | molded with the conventional disc shaping die. It is a graph which shows the relationship between the transfer depth of the groove | channel of the disk shape | molded with the conventional disk shaping die, and the radius of a disk.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Disc molding die 200 Disc molding die 3 Fixed die 3a Mold mirror surface 5 Movable die 11 Stamper 13 Cavity (gap part)
25 Mold temperature control piping 83 Spatial layer 91 Air heating device 93 Pipe 99 Flow rate control mechanism

Claims (4)

A disk molding die that is composed of at least two molds and molds an optical disk molded product by injecting a resin material into a gap formed in the mold,
A disk molding die characterized in that, in a mold to which a stamper having an information recording groove is attached, a space layer is provided between a mold mirror surface in contact with the outer peripheral portion of the stamper and a mold temperature control pipe. Type.   The disk molding die according to claim 1, further comprising hot air supply means for supplying hot air heated to a predetermined temperature to the space layer. Air heating means for heating the temperature of the compressed air to a predetermined constant temperature by flowing the compressed air through the temperature-adjusted pipe;
The disk molding die according to claim 1 or 2, wherein the compressed air heated to a predetermined constant temperature by the air heating means is supplied to the space layer. The air heating means includes a flow rate adjusting mechanism,
4. The disk molding die according to claim 3, wherein a flow rate of the compressed air supplied to the space layer is adjusted by the flow rate adjusting mechanism.