JP2003127190A - Injection molding mold assembly - Google Patents

Abstract

(57) [Problem] To improve the releasability of a disk substrate from a movable mold and an outer peripheral ring member, and prevent deterioration in appearance quality and performance of the disk substrate. SOLUTION: A movable mold 4 which is provided so as to be movable toward and away from a fixed mold 3 and forms a cavity 5 for molding a disk substrate 2 between the movable mold 4 and the fixed mold. A stamper 8 provided on the side cavity forming surface, and a molding surface 2 which is provided so as to be able to advance and retreat in parallel with the moving direction of the movable mold with respect to the fixed mold, and forms the outer peripheral end face of the disk substrate.
7 having an outer peripheral ring member 11. The outer peripheral ring member is divided into first and second divided portions 19 and 20, and an engagement surface 28 is provided between both divided end surfaces. An outlet 31 for blowing out compressed air is provided between the outer peripheral end surfaces of the disk substrate in the width direction.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding die apparatus for injection-molding a disk substrate of an optical disk such as an optical disk or a magneto-optical disk, and more particularly to an injection molding apparatus capable of improving the releasability of the disk substrate. The present invention relates to a molding die device.

2. Description of the Related Art As is well known, for example, disk substrates such as thin optical disks and magneto-optical disks, which are information storage media, are molded by injection molding using an injection molding die device. As shown in FIG. 8, this injection molding die device includes a fixed die 80, a movable die 81 provided on the fixed die 80 so as to be able to come into contact with and separate from the fixed die 80, and both the dies 80 and 81 face each other. A cavity portion 83 formed on each of the surfaces to mold the disk substrate 82, and an outer peripheral end surface 82 of the disk substrate 82.
A peripheral ring member 84 for molding a and a stamper 85 for transferring a predetermined concavo-convex pattern to the disk substrate 82.
And a driving means (not shown) for driving the movable mold 81 toward and away from the fixed mold 80. More specifically, the fixed mold 80 has a fixed-side mirror surface 80a to which a stamper is attached.
The movable mold 81 is formed with a movable side mirror surface 81a for molding the main surface 82b of the disk substrate 82. Further, in the movable die 81, on the outer peripheral portion of the movable side mirror surface 81a, with respect to the cavity portion 83 side, the outer peripheral ring member 84 is substantially parallel to the direction in which the movable die 81 approaches and separates from the fixed die 80. It is provided so that it can be moved. The cavity 83
When the movable die 81 is clamped to the fixed die 80, the movable side mirror surface 81a of the movable die 81 and the fixed die 80 are fixed.
The resin material is filled by the gap between the stamper and the main surface 85a and the molding surface 84a of the outer peripheral ring member 84. The outer peripheral ring member 84 is formed substantially in an annular shape, and the molding surface 84 a for molding the outer peripheral end surface of the disk substrate 82 is provided on the inner peripheral side, and is slidably supported in the movable mold 81. Moving pin 86a
It is adapted to be moved by a moving means 86 using air pressure or hydraulic pressure via the. The stamper 85
Is formed in a disk shape having a central hole, and is in contact with the fixed-side mirror surface 80a of the fixed die 80 to guide the inner-side stamper guide 87 and the outer-side that are slidably guided on the inner-side. The outer peripheral side stamper holder 88 is fixed. Further, in this injection molding die device, when the die is clamped, the outer peripheral ring member 84 is moved with a predetermined pressing force in the direction of approaching the fixed die 80, and the outer peripheral portion of the outer peripheral ring member 84 is on the outer peripheral side. Stamper holder 88
The outer peripheral ring member 84 and the stamper 8 when contacted with the
5, an exhaust gap 89 for exhausting the gas in the cavity 83 is secured. Therefore, in this injection molding die device, the molten resin material flows into the cavity portion 83 through the resin passage 90a into the sprue bush 90, and is generated from the air and the resin material inside the cavity portion 83. The gas is discharged from the exhaust gap 89 and the cavity 83 is filled with the resin material, whereby the filling of the resin material is completed. afterwards,
During the cooling for a predetermined time after the injection of the resin material is completed, a central hole is formed in the disk substrate 82 by the punch cutter 91, and the movable mold 81 with respect to the fixed mold 80 is opened by the drive mechanism. . Subsequently, by opening the mold, the molded disk substrate 82 is moved backward together with the outer peripheral ring member 84 and the movable mold 81 in the direction of arrow a2, and then the outer peripheral ring member 84 is moved by the moving means 86 in the direction of arrow a.
By moving so as to project in one direction, almost the entire main surface 82b of the disk substrate 82 floats up from the molding surface 81a of the movable mold 81 and is released. After that, the eject pin of the eject mechanism (not shown) provided on the inner peripheral side of the disc substrate 82 moves in the direction of the arrow a1 to move the disc substrate 82.
Are discharged from the movable mold 81, and a series of molding steps are completed.

However, in the above-mentioned conventional injection molding die device, after the mold is opened,
The outer peripheral ring member 84 projects and moves from the movable mold 81 so that the main surface 82a of the disk substrate 82 becomes the molding surface 8 of the movable mold 81.
When the pressing force by the outer peripheral ring member 84 is not sufficiently transmitted to the disk substrate 82 when peeled from 1a,
The main surface 82b of the disk substrate 82 cannot be floated over the molding surface 81a of the movable mold 81, and the inner peripheral portion of the disk substrate 82 contacts the molding surface 81a of the movable mold 81. It remains in contact with them. Therefore, a release mark may occur between the outer peripheral side and the inner peripheral side of the disc substrate 82. Also, this disk substrate 8
It is conceivable that compressed air may be blown between the second main surface 82b and the molding surface 81a of the movable mold 81 to improve the peelability of the disk substrate 82 from the movable mold 82.
Good peelability cannot always be obtained depending on the location where the compressed air is blown out. In particular, since the peelability between the outer peripheral end surface 82a of the disc substrate 82 and the molding surface 84a of the outer peripheral ring member 84 is not sufficiently taken into consideration, good peelability of the disc substrate 82 with respect to the outer peripheral ring member 84 cannot be obtained. The present invention has been devised in view of the actual state of the conventional injection molding die apparatus, and after the fixed mold and the movable mold are opened, compressed air is blown to the outer peripheral end face side of the disk substrate. In particular, it is an object of the present invention to provide an injection molding die device capable of improving the peeling property of a disk substrate from an outer peripheral ring member.

According to a first aspect of the present invention, there is provided a fixed die and a disc-shaped recording medium provided between the fixed die and the fixed die so as to be able to come into contact with and separate from the fixed die. A movable die for forming a cavity for molding a disc substrate, a stamper provided on the cavity forming surface on the fixed die side for transferring information to the disc substrate, and a moving direction of the movable die with respect to the fixed die. And an outer peripheral ring member having a molding surface for molding the outer peripheral end face of the disk substrate, the outer peripheral ring member being provided in the width direction midway of the molding surface. It is characterized in that it is divided into two parts, and an air outlet for blowing air is formed from the divided end face to the outer peripheral end face of the disk substrate. Therefore, according to the present invention, after the fixed mold and the movable mold are released from each other, when the outer peripheral ring member projects and moves from the movable mold, the compressed air flowing from the air collecting passage into the outlet is From this outlet, it directly abuts on a substantially central portion of the outer peripheral end face of the disc substrate in the width direction, flows out between the outer peripheral end face of the disc substrate and the molding surface of the outer peripheral ring member on which the outer peripheral end face is molded, and is movable. While flowing around between the molding surface of the mold and the main surface of the disk substrate, it flows toward the center of the disk substrate. Therefore, the releasability of the outer peripheral end surface of the disc substrate from the outer peripheral ring member is improved, and the releasability of the disc substrate from the molding surface of the movable mold is improved. Claim 2
According to the invention described in (3), an engaging surface that engages with the outer peripheral portion of the disk substrate is formed on the inner peripheral portion of the divided portion of the outer peripheral ring member, and an air collecting passage is annularly formed in the vicinity of the engaging surface. And a plurality of the outlets communicating with the air collecting passage are formed in the engagement surface along the radial direction. The invention according to claim 3 is characterized in that the engagement surface of the outer peripheral ring member causes the outer peripheral portion of the disk substrate to project and is released.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a concrete embodiment of the present invention will be described in detail with reference to the drawings on an injection molding die apparatus for molding a disk substrate of a magneto-optical disk. The injection mold apparatus according to the present invention is, for example, ISO / IEC152.
Diameter 13 used for magneto-optical disk conforming to 8 standards
It is applied to mold 0mm disc substrates. This magneto-optical disk has a recording capacity of, for example, 5.2 gigabytes. As shown in FIG. 1, the injection molding die apparatus 1 includes a set of a fixed die 3 and a movable die 4 each having a cavity 5 for molding a disc substrate 2, and a fixed die 3 of these.
And a fixed side mounting plate 6 and a movable side mounting plate 7 to which the movable mold 4 is mounted respectively, a stamper 8 for transferring a predetermined concave-convex pattern to the disk substrate 2, and an outer peripheral portion of the stamper 8 on the fixed mold 3 An outer peripheral side stamper holder 9 for fixing the outer peripheral side stamper, an inner peripheral stamper guide 10 for guiding the inner peripheral portion of the stamper 8, and an outer peripheral ring member 11 for molding the outer peripheral end surface 2a of the disk substrate 2. Further, the injection molding die device 1 includes a frame die 12 for guiding the movable die 4 with respect to the fixed die 3, an adjusting spacer 13 for adjusting the size of the cavity portion 5, and a disc substrate 2.
Gate punch 1 for cutting the gate near the center hole of
4 and. As shown in FIG. 1, the fixed mold 3 is provided with a fixed-side mirror surface 15 to which the stamper 8 is attached, while the movable mold 4 is arranged so as to face the fixed mold 3. The fixed mold 3 is provided so as to be movable in the arrow a1 direction and the arrow a2 direction. Further, the movable mold 4 is provided with a movable side mirror surface 16 (hereinafter referred to as a molding surface 16) for molding the main surface 2b of the disk substrate 2. Further, the fixed mold 3 and the movable mold 4 are respectively provided with temperature control circuits 17 and 17 through which cooling water for cooling the cavity 5 flows. A spool bush 18 into which a molten resin material injected by a screw of an injection molding machine (not shown) flows is provided in the center of the fixed side mounting plate 6 and the fixed mold 3. As the resin material, for example, polycarbonate, PMMA (polymethylmethacrylate) or the like is used. Further, the gate cut punch 14 is movably provided at the center of the movable side mounting plate 7 and the movable mold 4. The stamper 8 is formed in a disk shape having a center hole, and a predetermined concavo-convex pattern such as a pre-groove and a pre-format pit is provided on the surface facing the cavity portion 5, and the stamper 8 is fixed. It is abutted and fixed on the fixed side mirror surface 15 side. The outer peripheral side stamper holder 9 is formed into a substantially cylindrical shape, and an engaging collar portion 9a that engages with the outer peripheral portion of the stamper 8 is integrally formed on the inner peripheral portion. The outer peripheral ring member 11 is shown in FIG. 1, FIG.
As shown in (A) and (B), the outer stamper holder 9
Side and the movable mold 4 side are divided into two parts, and the first dividing part 1 is formed.
9 and the second divided portion 20 are integrally connected by a bolt and a nut, which are fastening means (not shown), and are formed in a substantially annular shape as a whole, and the molding surface of the movable mold 4 is formed. It is located on the outer peripheral side of 16. Also,
The outer peripheral ring member 11 is provided on the movable mold 4 so as to be able to advance and retreat in the arrow a1 direction that advances in parallel with the moving direction with respect to the fixed mold 3 and in the a2 direction that retracts, and the movable mold 4 and the movable side. A plurality of projecting rods 21 which are drive mechanisms provided inside each of the mounting plates 7 are driven forward by compressed air supplied through an air passage 22. Further, the maximum amount of protrusion of the outer peripheral ring member 11 is set to about 1.4 mm to 1.7 mm, and therefore, the predetermined amount is set to 1.2 mm which is equal to the thickness of the disk substrate 2 molded at the time of mold clamping. The protrusion amount of 0.2
It is adapted to move forward in the direction of arrow a1 from mm to 0.5 mm. Further, in the outer peripheral ring member 11, an exhaust gap 23 for exhausting gas generated in the cavity portion 5 is provided between the main surface of the stamper 8 and the facing surface that faces the main surface of the stamper 8 during mold clamping. Has been formed. This exhaust gap 2
3 is set to about 20 μm, which prevents the molten resin material from flowing into the exhaust gap 23, and prevents burrs from being formed on the outer peripheral edge of the molded disc substrate 2. . Further, the outer peripheral ring member 11 is
An annular protrusion 24 protruding toward the stamper 8 is provided on the inner peripheral side of the first divided portion 19, and a vertical inner peripheral surface 25 of the annular protrusion 24 and an inner periphery of the second divided portion 20 on the annular protrusion 24 side. The vertical inner peripheral surface 26 of the end portion is the outer peripheral end surface 2 of the disk substrate 2.
It is a molding surface 27 for molding a. Therefore, the cavity 5 includes the main surface of the stamper 8 of the fixed mold 3, the molding surface 16 of the movable mold 4, and the outer peripheral ring member 1.
1 molding surface 27 and its width W is set to 1.2 mm. Further, the inner peripheral surface 25 of the first divided portion 19 and the inner peripheral surface 26 of the second divided portion 20 which form the molding surface 27 are formed in a step shape in which the side of the second divided portion 20 projects. A horizontal step surface is formed as an engaging surface 28 that is located substantially at the center of the disc substrate 2 in the thickness direction and engages with the outer peripheral portion of the disc substrate 2. As shown in FIG. 2A, the engagement surface 28 is formed parallel to the main surface 2b of the disc substrate 2, and
It is formed as a continuous annular surface over the outer circumference of the disk substrate 2. Further, the width W of the engagement surface 28 in the radial direction of the disk substrate 22 is set to 0.15 to 0.4 mm (preferably 0.25 to 0.35 mm). Further, the divided portions 19 and 20 of the outer peripheral ring member 11 are formed by being divided along the radial direction from a substantially central position of the axial thickness width of the outer peripheral ring member 11, and the abutting edges 29 of the divided end surfaces thereof. However, as shown in FIG.
It is formed in an inclined shape from the 4 side to the lower side to a predetermined range, and is further formed horizontally from here. Then, the air collecting passage 30 is formed in the inclined portion of the butting edge 29 by notching the slanted dividing surface of the second dividing portion 20, and the butting edge 29 on the side of the annular projection 24 is formed. An outlet 3 communicating with the air collecting passage 30 in the horizontal portion.
1 is formed. As shown in FIGS. 1 and 2 (A), the air collecting passage 30 is formed over the entire inclined portion of the abutting end edge 29, is formed in a substantially truncated cone shape, and is formed at a substantially central position. An air supply passage 32 formed in the first divided portion 19 communicates with each other, and functions as a collector that collects the compressed air supplied from the air supply passage 32 in an annular shape. Further, the air supply passages 32 are formed at four positions in the circumferential direction of the first division portion 19, and each is connected to a compressed air supply circuit (not shown) including a control valve, an air pump and the like.
In addition, an annular seal member 33 that prevents the compressed air in the blowout port 31 from leaking to the outside through the divided edge is provided at both of the divided edges on the outer peripheral side of the blowout port 31, the second divided portion. It is fitted in a seal groove 34 formed on the divided surface of 20. The outlet 31 is shown in FIG.
As shown in (A) and (B), the annular protrusion 2 of the first divided portion 19
Grooves are formed along the radial direction on the divided surface on the 4 side, eight are formed at equal intervals in the circumferential direction, and each tip opening 31a is formed horizontally along the engagement surface 28. ing. Therefore, each of the tip openings 31a is radially directed to a substantially central portion of the molded disk substrate 2 in the width direction, and the disk substrate 22 molded by the engaging surface 28.
Compressed air is blown directly to the stepped surface of the. The height (groove depth) of the air outlet 31 is
H is set to 0.015 to 0.03 mm,
The width and length are set to 3-5 mm. As described above, since the opening area of the blowout port 31 is set to be small, it becomes possible to prevent the molten resin flowing into the cavity portion 5 from flowing into the blowout port 31. Hereinafter, the operation of the injection molding die apparatus 1 of the present embodiment will be described. In the injection molding die apparatus 1, the movable die 4 is moved with respect to the fixed die 3 in the arrow a1 direction of FIG. The mold is clamped. When the mold is clamped, the molding surface 27 of the outer peripheral ring member 11 shows that the movable mold 4 has an arrow a1 with respect to the fixed mold 3.
By moving in the direction, the outer peripheral side stamper holder 9 of the fixed mold 3 is abutted, so that the thickness of the disk substrate 2 to be molded is retracted relative to the stamper 8 in the direction of arrow a2. Is projected with a predetermined projecting amount equal to. After that, the cavity portion 5 including the molding surface 27 of the outer peripheral ring member 11 having a predetermined protrusion amount with respect to the molding surface 16 of the movable mold 4, the main surface of the stamper 8 and the molding surface 16 of the movable mold 4 is formed. A molten resin material is filled therein by a not-shown injection molding machine through a resin passage 18a in the spool bush 18. Then, after the molten resin material is completely filled in the cavity portion 5, pressure holding and cooling are started, and the gate cut punch 14 is moved in the direction of the arrow a1 in a delayed manner, whereby the disk substrate 2 The gate in the vicinity of the center hole is cut, and the mold is opened after a predetermined cooling time. Thereafter, the movable mold 4 is moved in the direction of the arrow a1 with respect to the fixed mold 3 to open the mold, and at the time of this mold opening, the disk substrate 22 is integrated with the movable mold 4 relative to the fixed mold 3. Although trying to move in the direction of the arrow a2, the outer peripheral ring member 11 is moved toward the molding surface 16 of the movable mold 4 by the arrow a1.
It advances in the direction and is projected with the maximum projection amount. Then, at this time, compressed air is supplied from the compressed air supply circuit to each air supply passage 32, and this compressed air flows into the air collecting passage 30 as it is, and from here, it is further branched to each outlet 31. Tip opening 3 of each outlet 31
It is directly sprayed from 1a through the engagement surface 28 to the stepped surface at the substantially central portion of the outer peripheral end surface 2a of the disk substrate 2. Thereafter, the compressed air spreads from the stepped surface of the disk substrate 2 to the entire outer peripheral end surface 2a, and further circulates between the outer peripheral portion of the main surface 2b of the disk substrate 2 and the molding surface 16 of the movable mold 4, The air flows into the inner peripheral portion of the main surface 2b and spreads over the entire main surface 2b of the disk substrate 2 to form an air layer between the main surface 2b and the molding surface 16. Therefore, the disk substrate 2 is
The main surface 2b is satisfactorily released from the molding surface 16 of the movable mold 4, and the outer peripheral portion is the engagement surface 2 of the outer peripheral ring member 11.
8 is engaged. After that, the inject pin (not shown) moves in the direction of the arrow a1, so that the disk substrate 2 is disengaged from the engaging surface 28 of the outer peripheral ring member 11 and ejected from the movable mold 4. Disc substrate 2 ejected
Is adsorbed and taken out by, for example, an adsorbing member of a holding means (not shown) and conveyed to the next step. As described above, according to the injection molding die apparatus 1 and the molding method thereof of the present embodiment, by providing the engaging surface 28 that engages with the outer peripheral portion of the disk substrate 2, the outer peripheral ring member at the time of mold release. 11
Of the molding surface 16 of the movable mold 4
On the other hand, since the disk substrate 2 can be floated and released so as to be uniformly spaced by a predetermined amount over the entire main surface 2b, a mold release mark is generated on the main surface of the molded disk substrate 22. Can be prevented. Moreover, in this injection molding die apparatus 1 and its molding method, compressed air that has flowed into the air collecting passage 30 prior to the outer peripheral ring member 11 projecting from the movable die 4 or in synchronism with each other is blown out at each outlet. 31 to the outer peripheral end surface 2 of the disk substrate 2
Since the compressed air is blown directly to the substantially central portion of the a, the compressed air is generated by the outer peripheral end surface 2a and the main surface 2b of the disk substrate 2.
Since it goes around to form an air layer in these parts,
The peelability of the disk substrate 2 from the molding surface 16 of the movable mold 4 and the engagement surface 28 of the outer peripheral ring member 11 is improved. In particular, the compressed air is first applied to the outer peripheral end surface 2 of the disk substrate 2.
Since it is directly blown to the step surface in the substantially central portion of a, the compressed air is not only excellent in peelability between the step surface and the engaging surface 28 with which the step surface abuts, but also the compressed air.
Since it is possible to sufficiently and swiftly cover the entire main surface 2b, the peelability of the disk substrate 2 from the movable mold 4 and the outer peripheral ring member 11 is further improved. In the present embodiment, the engagement surface 28 is the main surface 2 of the disc substrate 2.
Although it is formed parallel to b, it is not limited to this.
As shown in (B), for example, a sloped surface 28 of 30 ° or 45 °
A (chamfered shape) may be used to facilitate air wraparound. Further, since the compressed air can be uniformly dispersed and supplied to the blowout ports 31 by the air collecting passages 30, the compressed air blown out from the blowout ports 31 can be supplied to the outer peripheral end surface 2a of the disc substrate 2 and the disc substrate 2. It can be uniformly supplied to the molding surface 16 of the movable mold 4. Then, when the disc substrate 2 molded by the injection molding die device 1 and the disc substrate 2 molded by the device having no compressed air blowing mechanism are observed through the deflecting plate, no blowing mechanism is provided. Although some disk substrates 2 molded by the apparatus had an abnormal deflection from the outer edge to the inner side by about 2 to 3 mm, the disk substrate 2 molded by the apparatus 1 of the present embodiment did not show any abnormal deflection. Next, an MO disk (hereinafter referred to as a disk A) created by using the disk substrate 2 molded by the injection molding mold apparatus 1 of the present invention and a conventional mold apparatus having no blowing mechanism were molded. MO disk created using a normal disk substrate 2 (hereinafter referred to as disk B)
The specific signal balance signal of was observed experimentally. As shown in FIG. 4, the MO disks A and B include a disk substrate 2 (a), a recording layer b formed on the disk substrate a, and a protective layer formed on the recording layer b. c
It consists of and. The recording layer b is composed of a first dielectric film d made of SiN or the like, a magneto-optical recording film e made of a magnetic material for magneto-optical recording, a dielectric film f made of SiN or the like, or Al. The reflective film g and the reflective film g are laminated. The waveform of the difference signal at a position 2 mm (radius 41 mm) from the outer peripheral edge of these disks A and B is shown in FIG.
And shown in FIG. As the recording data, a repeating signal (2T signal) of the mark and space having the shortest mark length (0.385 μm) is recorded. I2T in the figure represents the amplitude of the recording signal, and ISI is the signal fluctuation due to microcracks. The value of this signal fluctuation (ISI) standardized by the amplitude (I2T) when the shortest mark length is recorded is important in the system. According to the result of this experiment, the value of ISI / I2T at a radius of 41 mm was about 0.08 in the disk A, while it was 0.37 in the disk B. Further, FIG. 7 shows data obtained by measuring ISI / I2T for each radius. Since the outer diameter of the disk substrate 2 is 43 mm in radius, the position of radius 40 mm corresponds to 3 mm from the outer edge. As is clear from these results, the disc A formed by the outer peripheral ring member 11 having the blowout mechanism as in the present embodiment is superior to the disc B having no blowout mechanism. . The present invention is not limited to the configuration of the above-described embodiment, and for example, the stamper 8 can be attached to the movable mold 4 instead of the fixed mold 3, and in this case, the disk substrate 2
The outer peripheral end of the outer peripheral stamper is determined by the inner peripheral surface of the outer peripheral stamper holder 9.
By this, it becomes possible to mold the disk substrate 2 with no microcracks or polarization abnormality at the outer peripheral edge. Further, the air collecting passage does not necessarily have to be formed between the divided end faces. It goes without saying that the present invention can be widely applied not only to the molding of the MO disk but also to the molding of the disk substrate 2 such as a phase change disk or the disk substrate of 90 mm diameter type.

As is apparent from the above description, claim 1
According to the invention described in (1), the compressed air is blown from each of the outlets to a substantially central position of the outer peripheral end surface of the disk substrate. Therefore, the compressed air is applied to the outer peripheral end surface of the disk substrate, the main surface of the disk substrate and the movable mold. Since the air layer is formed around these molding surfaces by forming an air layer in these portions, the releasability of the disk substrate from the movable mold and the outer peripheral ring member becomes good. In particular, since the compressed air is first directly blown to the substantially central position of the outer peripheral end surface, good peelability between the outer peripheral end surface and the molding surface of the outer peripheral ring member with which the outer peripheral end surface abuts is, of course, Since compressed air can be sufficiently and quickly distributed to the main surface side of the disk substrate, the peelability of the disk substrate from the movable mold and the outer peripheral ring member is further improved. As a result, it is possible to effectively prevent the generation of a release mark on the disc substrate, and moreover, the compressed air is simply blown to separate the disc mark, so that the appearance quality of the disc substrate 2 is not deteriorated and the product is not only produced. It does not affect the function of. According to the second aspect of the present invention, the outer peripheral ring member is provided with the engaging surface that engages with the outer peripheral portion of the disk substrate. Since the disk substrate can be floated and released from the molding surface of the mold so as to be uniformly separated by a predetermined amount over the entire main surface, the disk substrate is combined with the good releasability by the compressed air. The releasability from the movable mold can be further improved. According to the third aspect of the present invention, since the outer peripheral portion of the disc substrate is projected by the engaging surface of the outer peripheral ring member to release the disc substrate, the releasability of the disc substrate is further improved. become.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of an injection molding die device of the present invention.

FIG. 2A is an enlarged view of a portion A in FIG. 1, and B is an enlarged view showing another example.

FIG. 3A is a perspective view of one divided portion of the outer peripheral ring member used in the present embodiment, and B is a perspective view of the other divided portion.

FIG. 4 is an enlarged cross-sectional view of an essential part of an MO disk in which a recording layer and the like are laminated on the upper surface of a disk substrate 2 molded by the injection molding die device of this embodiment.

FIG. 5 is a characteristic diagram of MO signals of an MO disc using the disc substrate 2 set to a radius of 41 mm in the present embodiment.

FIG. 6 Radius 41 mm molded by a conventional injection molding die device
M of the MO disc using the disc substrate 2 set to
The characteristic diagram of O signal.

FIG. 7 is a characteristic diagram of radius dependency of a signal imbalance signal.

FIG. 8 is a cross-sectional view showing a conventional injection molding die device.

[Explanation of symbols]

1 ... Injection mold equipment 2 ... Disk substrate 2a ... Outer peripheral end face 2b ... Main surface 3 ... Fixed mold 4 ... Movable mold 5 ... Cavity 8 ... Stamper 11 ... Outer ring member 19 ... 1st division part 20 ... 2nd division part 27 ... Molding surface 28 ... Engaging surface 29 ... Butt edge 30 ... Air collecting passage 31 ... Blowout port

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Jun Shimizu             6-735 Kita-Shinagawa, Shinagawa-ku, Tokyo Soni             -Inside the corporation F term (reference) 4F202 AH38 AH79 CA11 CB01 CK06                       CK53 CK74 CM04 CM08

Claims (3)

[Claims] 1. A fixed mold, and a movable mold which is provided so as to be able to come into contact with and separate from the fixed mold and which forms a cavity for molding a disc substrate of a disc-shaped recording medium between the fixed mold and the movable mold. A stamper provided on the cavity forming surface of the fixed mold for transferring information to the disc substrate; and a disc substrate provided so as to be movable back and forth in parallel with a moving direction of the movable mold with respect to the fixed mold. And an outer peripheral ring member having a molding surface for molding the outer peripheral end surface of the outer peripheral ring member, the outer peripheral ring member is formed separately from the middle of the width direction of the molding surface, and the disk substrate is formed from the divided end surface. An injection molding die device, characterized in that an air outlet for blowing air is formed on the outer peripheral end face of the. 2. An engaging surface which engages with an outer peripheral portion of the disk substrate is formed on an inner peripheral portion of a divided portion of the outer peripheral ring member, and an air collecting passage is annularly formed in the vicinity of the engaging surface. The injection-molding die device according to claim 1, wherein a plurality of blow-out ports are formed on the engaging surface and communicate with the air collecting passage along the radial direction. 3. The injection molding die apparatus according to claim 2, wherein the engaging surface of the outer peripheral ring member causes the outer peripheral portion of the disk substrate to project and is released.