JPH07100866A - Injection molding machine and information recording carrier manufactured thereby - Google Patents

Abstract

PURPOSE:To provide an injection molding machine adapted to mold a thin information recording carrier (e.g. an optical disk having a thickness of 0.6mm of a half of a compact disk having a thickness of 1.2mm). CONSTITUTION:Stampers 9, 17 are provided on both surfaces of a stationary mold 2 and a movable mold 3 of molds 1, and slow cooling plates 8, 16 are provided on rear surfaces of the stampers of both surfaces. A collar 21 of an inner peripheral holder 10 of the mold 2 side is displaced from a collar 22 of an inner peripheral holder 18 of the mold 3 side, and the stampers 9, 17 of both surfaces are fixed. Further, (the stamper blocks of) the molds 2, 3 are so set that heat conductions become symmetrical. After resin is charged, a cut pin 15 is advanced before the resin is solidified, and mold clamping force is immediately increased to be molded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding apparatus and an information record carrier manufactured by the apparatus, and more particularly to a thin information record carrier (for example, 0.6 mm which is half of a 1.2 mm thick compact disc). The present invention relates to an injection molding apparatus suitable for molding a thick optical disc) and an information record carrier manufactured by the apparatus.

[0002]

2. Description of the Related Art In recent years, optical disc type information recording carriers (optical discs) have been developed aiming at high density, large capacity and miniaturization. There is an injection compression molding method in which a polycarbonate resin is used and molding is performed using an injection molding device as one of the methods for manufacturing the optical disc type information recording carrier.

As shown in FIG. 7, a stamper block 41 having a desired signal engraved thereon is attached to an injection molding apparatus.
a, or one of the stamper blocks 43a of the fixed mold part 43 that faces the movable mold part 41 with a cavity 42 therebetween, and the molten resin (not shown) is filled into the mold cavity 42 at high speed. The mold clamping force at this time is a pressure at which the mold is appropriately opened by the resin filling pressure, and after the resin in the gate portion 44 is solidified, the mold clamping force is increased to transfer the signal of the stamper 40 to the information recording carrier, After solidification, the mold is opened and the desired information recording carrier is taken out of the mold. In addition, 45 is an outer ring, 4
6 is a sprue bush, 47 is a cut pin, and 48 is an inner peripheral holder. The size of this information recording carrier is an outer diameter φ1.
It has a diameter of 20 mm, an inner diameter of 15 mm, and a thickness of 1.2 mm (this is the standard size of a general compact disc).

By the way, the above-mentioned simple substance structure has a drawback that the weather resistance is poor (there is a surface wobbling or warping) because a reflecting film or a protective film is attached to one surface (on the signal surface side), and a countermeasure against it. One of the methods is to attach a reflective film to an information recording carrier having a half thickness, and attach two information recording carriers so that the reflective film is on the inside. Furthermore, there is also one in which a plurality of thin information recording carriers are used and the signal portion is multi-layered to further increase the density, for example, Japanese Patent Publication No. 61-2.
There is one described in Japanese Patent No. 7815.

As described above, at present, in order to improve weather resistance and increase density, a thin information recording carrier (for example,
0.6 which is half of a 1.2 mm thick compact disc
Therefore, it is necessary to form a mm-thick optical disk).

[0006]

However, even if a thin information recording carrier is molded by the conventional injection molding apparatus and its manufacturing method, a good product cannot be obtained. For example, when an analysis is performed when a thin information recording carrier having a thickness of 0.6 mm is molded, the filling pressure is 8 times, the cooling rate and the thermal stress are 2 times, and the information recording carrier having a large stress due to the molding conditions. It is estimated that On the other hand, the rigidity is 1/8
Therefore, if the stress is the same, it is estimated that the amount of deflection such as surface wobbling and warp angle becomes eight times. To make this rigidity the same as that of a conventional 1.2 mm thick substrate, it is possible to bond two substrates, but it is estimated that the amount of deflection will be large. In particular, the effect of bonding is proportional to the fourth power of the bending period, so that reduction in the high frequency region cannot be expected.

Therefore, a 0.6 mm thick substrate is 1.2 mm
It is necessary that the stress be smaller than that of a thick substrate, and that the surface deflection and warp angle have small high frequency components. However, as described above, it is not possible to solve the problem only by making it possible to mold a thin information record carrier by the conventional manufacturing method. actually,
When a thin information recording medium (0.6 mm thick) was molded by the conventional method, the physical properties of birefringence and transferability of the single substance were poor, and the warp angle and surface run-out of the conventional information recording medium ( The thickness was worse than 1.2 mm (Comparative Example 1 described later)
reference).

Furthermore, a 0.6 mm thick substrate and 1.2 mm
The molding of thick substrates will be described in detail in comparison. Generally, when considering a cooling and solidifying process of a polymer material such as a polycarbonate resin by an injection molding method, there is a state as shown in FIG. At the time of filling, the flow of the resin is fast in the central portion and becomes zero where it is in contact with the stamper or the surface of the mold, and a shear rate occurs (see (A) of FIG. 6). As a result, the stamper that is being cooled and the polymer chains on the surface of the mold are subjected to a large shearing force by the melt and are solidified while being stretched in the flow direction (see (B) in the same figure). Further, the polymer material in the central portion is stretched in the flow direction during filling, but is not solidified after filling, so that the polymer chains become random due to stress relaxation, and are cooled and solidified as they are. However, the layer close to the surface layer is cooled and solidified while being oriented (see (C) in the same figure).

When the filling pressure is high in the process of causing the orientation, the time during which the orientation is maintained becomes long, and the resin after solidification has a thick orientation layer and a thin non-orientation layer. The thicker the alignment layer, the greater the thermal stress and the greater the birefringence.

Further, one of the causes of the surface runout and the warp angle is caused by the imbalance when the heat of the filled resin is taken by the fixed mold part and the movable mold part. That is, it is caused by the thickness variation of the surface layer and the orientation layer.

Here, a 0.6 mm thick substrate and 1.2 mm
Considering a thick substrate, the analysis result shows that the substrate having a thickness of 0.6 mm has a higher filling pressure and a higher cooling rate than the substrate having a thickness of 1.2 mm, and thus the orientation layer can be thickened. Further, since the thermal stress is high and the rigidity is low, a slight amount of unevenness in the thickness of the alignment layer is large. Therefore, it is necessary to make the resin filling pressure and thermal stress smaller than the 1.2 mm thick substrate. Further, in order to reduce the surface runout and the warp angle, it is necessary to make the temperature gradient of the cooling process on the fixed side the same as that on the movable side.

To reduce the filling pressure and thermal stress, (a) decrease the resin viscosity, (b) increase the resin temperature, (c) increase the mold temperature, and (d) make the cavity easy to flow resin. A method such as doing is possible. However, regarding (a), the grade of the resin used for the optical disc type information recording carrier is already the one having the lowest molecular weight, and the solution from the resin side cannot be expected. For (b) and (c), the resin temperature,
An attempt was made to raise the mold temperature to the maximum that could be molded, but the filling pressure was considerably higher than when a 1.2 mm thick information record carrier was molded.

Regarding (d), for example, as shown in FIG. 8, a shape in which the flanges of the inner peripheral holders 49x and 49y are eliminated can be considered (see FIG. 7). However, stampers 40x, 40
When the y is deformed, the stamper has a drawback that the circularity distortion of the distortion signal and the eccentricity increase. Further, an information record carrier formed by this method is shown in FIG. 9, which corresponds to the deformed portions of the stampers 40x and 40y and is a.
This method is not a good solution because there is a problem that burrs are formed on the part and the surface run-out of the information recording carrier becomes large due to the burrs when taken out.

Now, the position of the collar 48a of the inner peripheral holder 48 will be considered with reference to FIG. The flange 48a of the inner peripheral holder 48 has a structure that prevents the stamper 40 from coming out of the inner peripheral holder 48 when the inner diameter of the stamper 40 enters the outer diameter of the inner peripheral holder and is fixed to the stamper block 43a. This is for facilitating close contact with the stamper block 43a. The shape of an information recording carrier having a stamper attached to only one side like the conventional 1.2 mm-thick information recording carrier is shown in FIG. The information recording carrier 200 is formed with a recess c corresponding to the flange 48a of the inner peripheral holder 48.

As a result of molding an information record carrier having a thickness of 0.6 mm and an information record carrier having a thickness of 1.2 mm with a conventional mold,
There was no problem with the physical properties of the 2 mm-thick information recording medium, but 0.
The physical properties (especially the warp angle) of the 6 mm-thick information recording medium were quite bad. This is because the material of the stamper and the material of the mirror surface have different thermal conductivities, the cooling rates are different on the stamper side and the mirror surface side, and the alignment layer thicknesses on the stamper side and the mirror surface side are different.

As a countermeasure against this, a 0.6 mm thick information record carrier as shown in FIG. 5 is used as a mold structure in which stampers are attached to both sides to make the cooling rates of the fixed side and the movable side the same. In this information recording carrier 201, the physical property values are better than those described above, but if the die structure is such that the portion a in FIG. 5 is 0.3 mm or less and the portion b is 1 mm or more, the resin filling pressure is Unless it is high and the filling speed is considerably high, new problems occur such that the outer peripheral portion cannot be filled, and even if the outer peripheral portion is filled, the transferability of the outer peripheral portion deteriorates.

On the other hand, when the portion a in FIG. 5 is intended to be thick, it is necessary to make the flange of the inner peripheral holder thin, but there is a problem that machining is not possible or even if machining is possible, the life is short.

[0018]

Therefore, an information recording carrier 100 having a shape as shown in FIG. 3 is provided with a stamper on both sides and a mold structure in which the position of the flange of the inner peripheral holder is shifted between the fixed side and the movable side. And The physical property value was the smallest in this shape, and the filling pressure was also considerably smaller than when the information recording carrier 201 shown in FIG. 5 was molded.

However, the value was still worse than that of the information record carrier having a thickness of 1.2 mm. This is caused by rapid cooling during resin filling.As a countermeasure against this, a material with low heat conductivity and high heat resistance is inserted between the backside of the stamper and the mold surface to prevent rapid cooling of the resin temperature during filling. As a result of the examination, it was possible to achieve the same purpose at low cost. That is, (a) the die has a structure in which stampers having the same thickness are attached to both sides, the stamper block has the same material thickness, and the cooling grooves are plane-symmetric. (Please refer to (a) Double-sided stamper and (d) Symmetry of heat conducting surface of stamper block described later in the examples.) (A) In order to cool the resin at an appropriate speed, Between the back surface of the stamper and the front surface of the stamper block, a material having a small heat conductivity and heat resistance (slow cooling plate) and having the same thickness is used on both sides to form a mold structure. (See (c) Annealing plate described later in Examples). (C) The flange of the inner holder that holds the stamper has a shape that is offset from the fixed side and the movable side. As a result, the inner peripheral portion of the information recording carrier molded by this mold has a groove formed on both sides which is displaced. (See (b) Misalignment of the collar of the inner holder, which will be described later in Examples).

In view of the above points (a) to (c), the present invention provides an injection molding apparatus suitable for manufacturing a thin information record carrier and an information record carrier manufactured by the apparatus.

In order to solve the above problems, the present invention comprises a fixed mold portion 2 of an injection molding die 1 and a movable mold portion 3 facing the fixed mold portion 2 as shown in FIG. An injection molding apparatus for manufacturing the information record carrier of claim 1, wherein stampers 9 and 17 are provided on both surfaces of the fixed mold part 2 and the movable mold part 3, and slow cooling plates 8 are provided on the back surfaces of the stampers on both surfaces.
16 is provided, and the inner peripheral holder 1 on the fixed mold side is provided.
No. 0 collar part 21 and the collar part 22 of the inner peripheral holder 18 on the movable mold part side are provided so as to be displaced so as to fix the stampers 9 and 17 on both sides. provide.

Further, as shown in FIG. 3, for example, an annular groove x, is formed inside the signal portion 100a of the information recording carrier 100.
An information record carrier manufactured by the injection molding apparatus according to claim 1, wherein y is provided so as to be shifted on both sides.

[0023]

According to the injection molding apparatus configured as described above, the heat conduction surfaces on the fixed mold part 2 side and the movable mold part 3 side are symmetrical, and the resin cooling speed is substantially the same. Further, the flange portion 21 of the inner peripheral holder 10 on the fixed die portion 2 side and the movable die portion 3
Since the flange portion 22 of the inner peripheral holder 18 on the side is provided so as to be offset from each other, a narrow portion does not occur in the cavity 20 and resin filling is good.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the injection molding apparatus and the information recording carrier manufactured by the apparatus according to the present invention will be described.

(Embodiment 1) First, a concrete embodiment of the injection molding apparatus and the information recording carrier according to the present invention will be described with reference to FIGS. 1 and 3. FIG. 1 is an injection molding apparatus for manufacturing an information record carrier, which is a schematic cross-sectional view of a mold. FIG. 3 is a schematic sectional view of the information record carrier.

An injection molding apparatus according to the present invention (structure of a mold for manufacturing an information record carrier) will be described with reference to FIG. The injection molding die (mold) 1 is composed of a fixed die portion 2 and a movable die portion 3, and is fixed to a fixed die plate and a movable die plate of an injection molding machine (not shown) by screws (not shown), respectively. There is.

The fixed mold portion 2 includes a fixed side base plate 4 and a fixed side stamper block 5 for cooling grooves (space portions) 6.
And a sprue bush 7 is provided at the center. On the surface of the fixed-side stamper block 5, the fixed-side stamper 9 is sandwiched with the fixed-side gradually cooling plate 8 interposed therebetween.
Are held by the fixed side inner peripheral holder 10 and the fixed side outer peripheral ring 11.

Similarly, in the movable mold part 3, the movable base plate 12 and the movable stamper block 13 constitute a cooling groove (space part) 14, and a cut pin 15 is provided in the central part. On the surface of the movable side stamper block 13, a movable side stamper 17 is held by a movable side inner peripheral holder 18 and a movable side outer peripheral ring 19 with a movable side slow cooling plate 16 interposed therebetween.

In this state, when the injection molding machine is closed, the cavity 20 is formed, resin is injected into the cavity 20, and the information record carrier is injection molded. Further, the following (a) to (e) which are features of the injection molding apparatus according to the present invention will be described in detail.

(A) Double-sided stamper A fixed stamper 9 and a movable stamper 17 are provided on both surfaces of the fixed mold part 2 and the movable mold part 3 facing the fixed mold part 2. The movable stamper 17 is a stamper on which information to be recorded is engraved,
On the other hand, the fixed-side stamper 9 is conventionally unnecessary. By providing the fixed side stamper 9 in this way, the temperature gradient (resin cooling rate) is substantially the same in the movable mold part 3 and the fixed mold part 2 where the movable side stamper 17 is present.

(B) Misalignment of the flange of the inner peripheral holder As described above, the stampers are provided on both surfaces of the fixed mold part 2 and the movable mold part 3, but the flange part 21 of the fixed side inner peripheral holder 10 is provided.
And the flange portion 22 of the movable side inner peripheral holder 18 are configured so as not to be at the same position. That is, the collar portion 22 of the movable side inner peripheral holder 18 is provided so as to be outside the collar portion 21 of the fixed side inner peripheral holder 10. That is, when the flanges of the inner peripheral holders used in the fixed mold part 2 and the movable mold part 3 have the same size, the flange part has an extremely thin cavity (20) shape, and there is a problem that the filling pressure increases, and the like. The collar portions 21 and 22 of the inner peripheral holder are formed in a shape in which the fixed side portion 2 and the movable side portion 3 are displaced from each other. With this structure, the cavity 20 does not have an extremely thin portion, and it is not necessary to increase the pressure during resin filling.

Further, as shown in FIG. 3, the shape of the inner peripheral portion of the information recording carrier 100 molded by such a die is a shape in which the grooves x and y formed on both sides are deviated. In this case, the optical disk type information record carrier includes a type in which a hub is attached to the center portion, a type in which a hub is not attached, and various sizes according to applications. Since any type has the clamping area n inside the innermost peripheral signal portion m, it is desirable to provide the grooves x and y inside the innermost peripheral signal portion m excluding the clamping area n. For example, since the clamping area of an information record carrier having an outer diameter of 120 mm, such as a compact disc, is 26 mm to 33 mm, it is 33 mm.
The width is 0.5 mm to 3 mm and the depth is 0.
A groove shape on the circumference of 1 mm to 0.4 mm is preferable.
With such a configuration, the standards such as Red Book can be satisfied when they are laminated.

(C) Gradual Cooling Plates Gradual cooling plates 8 and 16 are provided on both surfaces of the fixed mold portion 2 and the movable mold portion 3 facing the fixed mold portion 2. The stationary side slow cooling plate 8 and the movable side slow cooling plate 16 have a thermal conductivity of 10 W / m · K or less and a heat resistant temperature of 80 ° C. in consideration of the thermal conductivity of Ni which is a stamper material.
The above materials, the same material, and the same thickness. As a result, the resin is not rapidly cooled during and after the filling, so that the resin filling pressure is lowered and the cooling rate is slowed, the non-alignment layer is increased, and the birefringence is reduced. Furthermore, since the slow cooling plates are attached to both sides, surface wobbling and warp angle can be reduced.

(D) Symmetry in the heat conducting surface of the stamper block Further, the fixed stamper block 5 and the movable stamper block 13 are made of the same material having the same thermal conductivity and the same thickness,
The cooling groove 6 and the cooling groove 14 have the same shape and are plane-symmetric. As a result, the temperature gradients taken by the fixed mold part 2 and the movable mold part 3 are the same. In this embodiment (specific examples below), the material and thickness of the stamper block are fixed.
STAVAX (manufactured by UDDEHOLM) was used in the same movable manner, and the thickness was 20 mm. The groove shape was a spiral shape having a width of 7 mm and a depth of 6 mm.

(E) Operation of Cut Pin Further, the operation of the cut pin 15 is such that after the resin is filled, the cut pin 15 is advanced before the resin is solidified and the mold clamping force is immediately increased. By this operation, it is possible to prevent backflow of the resin when the mold clamping force is increased, and to obtain an information recording carrier having high transfer property, uniform transfer property over the entire surface, and low birefringence.

(F) Bonding Method (This point will be described in detail in Example 2) Further, many adhesives for bonding the information record carrier undergo curing shrinkage. Therefore, for the purpose of absorbing the shrinkage and reducing the surface wobbling and the warp angle caused by the molding, when the information recording carriers are stuck and bonded, the substrate is applied with an even load until the adhesive is cured. As a result, it is possible to manufacture an information record carrier having small surface wobbling and warpage.

(Embodiment 1) Next, an injection molding apparatus according to the present invention and an information recording carrier manufactured by the apparatus will be described.
A more specific description will be given. In the fixed side portion 2 of the mold 1, the outer diameter φ128 mm, the inner diameter φ35.6 mm, the thickness 0.25 m
m, a nickel stamper 9 and an outer diameter φ128 mm, an inner diameter φ35.6 mm, a thickness 0.3 mm polyimide slow cooling plate (heat conductivity 0.29 W / m K) 8 on the fixed side stamper block 5. Circumferential holder (size of collar 21 φ
33.4 mm to φ36.5 mm, thickness 0.2 mm) 10
It was attached by the outer peripheral ring 11.

On the other hand, on the movable side portion 3 of the die 1, the outer diameter φ1
66 mm, inner diameter φ41.6 mm, thickness 0.25 mm nickel stamper 17, outer diameter φ166 mm, inner diameter φ
41.6 mm, 0.3 mm thick polyimide slow cooling plate (heat conductivity 0.29 W / m K) 16 and a movable side stamper block 13 on the inner circumference holder (size of flange 22 φ).
39.4 mm to φ42.5 mm, thickness 0.2 mm) 18
It was attached by means of a peripheral ring 19.

Further, using a polycarbonate (average molecular weight 15000) as a molding resin, a resin temperature of 345
The resin was filled under the conditions of ℃ and mold temperature of 115 ℃, the cut pin 15 was immediately advanced, then the mold clamping force was increased, and after the resin was solidified, the gate cutting was performed. Then, the mold was opened to obtain a substrate 100 having an outer diameter φ120 mm, an inner diameter φ15 mm, and a thickness of 0.6 mm, which had the shape shown in FIG. The physical properties of the single plate are shown in Table 1. As will be described later, all physical properties were significantly reduced, and a good information record carrier having a thickness of 0.6 mm was obtained.

[0040]

[Table 1]

Comparative Example 1 Conventional 1.2 mm shown in FIG.
By changing the thickness of the outer peripheral ring 45 of the thick substrate mold, 0.6
A substrate having a thickness of mm can be molded. On the stamper block 43a of the fixed mold part 43 of the mold, the outer diameter φ128m
m, an inner diameter φ35.6 mm, and a thickness of 0.25 mm, and a nickel stamper 40 is used as an inner circumference holder 46 (size of the collar 46a φ33.4 mm to φ36.5 mm, thickness 0.2 m).
m) and the outer ring 45.

Further, using a polycarbonate (average molecular weight 15000) as a molding resin, a resin temperature of 345
The resin was filled under the conditions of a temperature of 150 ° C. and a mold temperature of 115 ° C. After the gate was sealed, the mold clamping force was increased and the cut pin 44 was used to cut the gate. The outer diameter φ12 having the shape shown in FIG.
Substrate 200 of 0 mm, inner diameter φ15 mm, thickness 0.6 mm
Got Table 1 shows the physical properties of the single plate.

Concrete Example 1 includes (a) the double-sided stamper, (b) the positional deviation of the collar of the inner peripheral holder, (c) the slow cooling plate, (d) the symmetry in the heat conducting surface of the stamper block,
(e) All of the features such as the operation of the cut pin are provided, and none of Comparative Example 1 is provided. Table 1
As is clear from Comparative Example 1, the specific example 1 is
The values were small in any of surface wobbling, warp angle, and birefringence, and a good information recording carrier was obtained.

Comparative Example 2 In FIG. 1, the fixed side portion 2 of the mold 1 has an outer diameter φ128 mm, an inner diameter φ35.6 mm,
Nickel stamper 9 with a thickness of 0.25 mm and outer diameter φ
128 mm, inner diameter φ35.6 mm, and thickness 0.3 mm of polyimide slow cooling plate (thermal conductivity 0.29 W / m K) 8 and an inner peripheral holder (size of flange 21 φ33. 4 mm to 36.5 mm, thickness 0.2 mm) 10 and the outer peripheral ring 11 were used for attachment.

On the other hand, on the movable side portion 3 of the mold 1, the outer diameter φ1
66 mm, inner diameter φ35.6 mm, thickness 0.25 mm nickel stamper 17, outer diameter φ166 mm, inner diameter φ
A slow cooling plate (heat conductivity 0.29 W / m K) 16 made of polyimide having a thickness of 35.6 mm and a thickness of 0.3 mm is mounted on the movable side stamper block 13 on the inner circumference holder (size φ of the collar 22).
33.4 mm to φ36.5 mm, thickness 0.2 mm) 18
It was attached by means of a peripheral ring 19. That is,
In this example, the collar 21 of the inner peripheral holder 10 and the collar 22 of the inner peripheral holder 18 are not displaced.

Further, using a polycarbonate (average molecular weight 15000) as a molding resin, the resin temperature is 345.
The resin was filled under the conditions of ℃ and mold temperature of 115 ℃, the cut pin 15 was immediately advanced, and then the mold clamping force was increased to solidify the resin, and then gate cutting was performed. Then, the mold was opened to obtain a substrate having an outer diameter φ120 mm, an inner diameter φ15 mm, and a thickness of 0.6 mm having the shape shown in FIG. Table 1 shows the physical properties of the single plate.

The specific example 1 and the comparative example 2 are different from each other only in the condition (b) of the positional deviation of the flange of the inner peripheral holder. As is clear from Table 1, even when compared with Comparative Example 2, in Example 1, the values were small in any of surface wobbling, warp angle, and birefringence, and also a good information record carrier was obtained.

(Embodiment 2) Next, a method for laminating the information recording carrier (hereinafter referred to as a disk substrate) manufactured according to Embodiment 1 will be described with reference to FIG. In FIG. 2, the base 30 has an opening 30a in the center thereof, and an ultraviolet irradiation device 31 is installed below the opening 30a so as to irradiate upward. On the base 30, there is a plate 32 made of a material that transmits ultraviolet rays (quartz glass or blue plate glass), and this plate 32 has a center pin 33 in the center.

There are two information recording carriers (disk substrates) 34 and 35 for pasting, using the center pin 33 as a guide. Further, a top plate 36 is installed on an air cylinder (not shown) through a universal joint (not shown) and evenly attached to the disc substrate when the information recording carriers (disc substrates) 34 and 35 are bonded. It can be loaded with various loads.

An ultraviolet curing type adhesive is used, and it is hung down by a dispenser on the circumference of about φ80 mm of the lower disk substrate 34, and the upper disk substrate 35 is placed on the disk substrate 34 so that air bubbles do not enter the resin. The resin is spread over the entire surface of the disk substrate. After that, the top plate 36 is pressed against the upper surface of the disk substrate 35, a uniform load is applied to the disk substrate, and ultraviolet rays are applied to the disk substrate from the lower side while applying a constant load to cure the resin.

(Specific Example 2) Further detailed description will be given.
Using the apparatus of FIG. 2 described above, two disk substrates formed by the method described in Embodiment 1 (the information recording carrier 10 in which the annular grooves x and y shown in FIG.
0) was used for bonding. As the lower disk substrate 34, a disk substrate containing no signal was used. As the upper disk substrate 35, a disk substrate having an Al sputtered film previously attached to the signal side was used. About 1.5 cc of UV curing resin (XR-11, manufactured by Sumitomo Chemical Co., Ltd.) is hung on the circumference of φ80 mm of the lower disk substrate 34, and the upper disk substrate 35 sets the signal downward so that air bubbles do not enter the resin. As described above, the ultraviolet curable resin was spread on the lower disk substrate 34.

After that, the top plate 36 is pressed against the upper surface of the disk substrate 35 and an even load of 1.1 kg / cm ² is applied to the disk substrate, and ultraviolet rays having an illuminance of 4.6 mw / cm ² (wavelength 310 nm) at the curing portion are applied. After checking for 15 seconds, a bonded disk substrate was obtained. When the surface deflection and the warp angle of this disk substrate were measured, the high results shown in Table 2 were obtained.

[0053]

[Table 2]

Comparative Example 3 Using the apparatus shown in FIG. 2, two disk substrates formed by the method described in Example 1 were bonded together. As the lower disk substrate 34, a disk substrate containing no signal was used. As the upper disk substrate 35, a disk substrate having an Al sputtered film previously attached to the signal side was used. Φ80m of lower disk substrate 34
About 1.5 cc of UV curable resin (XR-1
(1) made by Sumitomo Chemical Co., Ltd., and the upper disk substrate 35 was placed on the lower disk substrate 34 with the signal facing downward so that air bubbles did not enter the resin, and the ultraviolet curable resin was extended.

Thereafter, the top plate 36 is pressed against the upper surface of the disk substrate 35, and once on the disk substrate, 1.1 kg /
After applying a uniform load of cm ^2, illuminance 4.6 mW / cm ² of the cured portion in a state of releasing the load the ultraviolet (wavelength 310 nm) 1
After checking for 5 seconds, a bonded disk substrate was obtained. The surface deflection and the warp angle of this disk substrate were measured, and the values shown in Table 2 were obtained.

As is clear from Table 2, by adhering the disk substrate while applying a uniform load to the substrate, the surface wobbling and the warp angle are reduced, and a good information record carrier can be obtained.

In the second embodiment, the adhesive is not limited to the ultraviolet curable resin, but if the adhesive is of a type that contracts when it cures, it cures while applying a uniform load to the disk substrate. As a result, surface wobbling and warp angle can be reduced. The method for applying a constant load to the information recording carrier is not limited to the air cylinder.

[0058]

As described above in detail, the injection molding apparatus according to the present invention (and the information record carrier manufactured by the apparatus).
According to this, it is possible to reduce the physical characteristics such as surface wobbling, warp angle, and birefringence of the thin information recording carrier at low cost, and to obtain a thin information recording carrier having excellent characteristics.

[Brief description of drawings]

FIG. 1 is a view showing an embodiment of an injection molding apparatus according to the present invention, and is a schematic sectional view of a mold.

FIG. 2 is a conceptual diagram of an information recording carrier bonding device.

FIG. 3 is a schematic sectional view of an information record carrier manufactured by the injection molding apparatus according to the present invention.

FIG. 4 is a schematic sectional view of a conventional information record carrier.

FIG. 5 is a schematic sectional view of a conventional information record carrier.

FIG. 6 is a conceptual diagram showing a process in which orientation occurs.

FIG. 7 is a schematic cross-sectional view of a conventional mold.

FIG. 8 is a schematic cross-sectional view showing a clamped state of a stamper when using a collarless inner peripheral holder.

FIG. 9 is a schematic cross-sectional view of an information recording carrier molded using a collarless inner circumference holder.

[Explanation of symbols]

1 mold, 2 fixed mold part, 3 movable mold part, 4 fixed side base plate, 5 fixed side stamper block 6 cooling groove, 7 sprue bushing, 8 fixed side slow cooling plate, 9 fixed side stamper, 10 fixed side inner circumference holder , 11 fixed side outer ring, 12 movable side base plate, 13 movable side stamper block, 14 cooling groove, 15 cut pin, 16 movable side cooling plate 17 movable side stamper, 18 movable side inner peripheral holder,
19 movable side outer ring, 20 cavity, 21
Collar part of the inner peripheral holder on the fixed mold part side, 22 Collar part of the inner peripheral holder on the movable mold part side 30 Base, 31 UV irradiation device, 32 plate, 33 center pin, 34 disc substrate, 35 disc substrate, 36 top plate , 100 information record carrier, x, y annular groove of information record carrier

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display area // B29L 17:00

Claims (4)

[Claims] 1. An injection molding apparatus for manufacturing a thin information recording carrier, which comprises a fixed mold part of an injection molding die and a movable mold part facing the fixed mold part, the fixed mold part and the movable mold. Stampers are provided on both sides of the part,
An annealing plate is provided on the back surfaces of the stampers on both surfaces, and the flange portion of the inner peripheral holder on the fixed mold portion side and the flange portion of the inner peripheral holder on the movable mold portion side are provided so as to be offset from each other. An injection molding device characterized in that a stamper is fixed. 2. The compressing operation is performed by advancing the cut pin before the resin is solidified after the resin is filled in the cavity formed by the fixed mold part and the movable mold part. The injection molding apparatus described in 1. 3. The information recording carrier manufactured by the injection molding apparatus according to claim 1, wherein annular grooves are provided on both sides of the information recording carrier so as to be displaced inside the signal portion. 4. An information recording medium manufactured by the injection molding apparatus according to claim 1, wherein two information recording carriers having annular grooves on both sides which are offset from each other are adhered to each other while applying an equal load. An information recording carrier characterized by: