JP2003080567A - Apparatus for molding disc, method for manufacturing stamper, method for molding block, stamper and disc for fixing glass master, disc substrate and disc product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To mold an optical disc substrate by a method for assuring required transferability and other characteristics and then holding productivity good. SOLUTION: An apparatus for molding the disc comprises a pair of stampers 6, 6 mounted on both opposed surfaces of cavities 5 of molds 10 and 11, thereby molding to transfer necessary fine shapes to both surfaces of a molding. The apparatus further comprises a heat insulation stamper enclosing a heat insulator as any one of the pair of the stampers 6, 6. Thus, the transferability required for the disc substrate and other characteristics are assured and the disc substrate can be molded with the good productivity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention reads or additionally records information transferred on the surface of a thin plate molded article from the transfer surface side using either a contact type or non-contact type method.
Regarding a thin plate molded product used in an information recording device for rewriting, particularly, a disk molding device for molding a molded product, such as an optical disk substrate, on which a fine pattern engraved on the stamper is transferred to the surface, a stamper manufacturing method, The present invention relates to a block for fixing a glass master, a stamper, a disk molding method, a disk substrate, and a disk product.

[0002]

2. Description of the Related Art Conventionally, various types of optical discs such as CDs, MOs, DVDs, etc. have been used in a type suitable for read-only, write-once, and rewrite applications. Has been done. Various methods have been attempted to further increase the amount of information loaded on one optical disc and further improve the convenience of the user.

As one of such methods, a method called "surface recording method" has been proposed. In the conventional optical disc, as shown in FIG. 1, the laser beam L is incident and focused through the optical disc substrate 3 from the side opposite to the information face 2 of the optical disc 1 to read the information on the information face 2 or additionally write the information. While the rewriting method is adopted, in the surface recording type optical disc 1a, as shown in FIG. 2, the laser beam L is incident and condensed from the information surface 2 side through the thin cover layer 4. I am collecting. The laser beam L used in the surface recording type optical disc 1a has a wavelength much shorter than that of the conventional one, and is based on an optical system capable of finely focusing on the information surface. As a result, it is possible to mount information on the information surface 2 with higher density, and the total amount of information that can be mounted on one optical disk is also increased. In each drawing, r is the rotation axis of the optical disc 1.

By the way, when the above-mentioned surface recording method is adopted and the amount of information that can be mounted on one optical disk is further expanded, as shown in FIG. 3, the optical disk 1b is used.
If information is loaded on both sides, the amount of information can be simply and easily doubled.

When molding the above-mentioned optical disk substrate having information surfaces on both sides, a cavity 5 as shown in FIG. 4 is formed.
An optical disk substrate molding apparatus having a mold in which stampers 6, 6 are mounted on both of the two surfaces facing each other is used. In the figure, 7 is a spool, 8 is a stamper inner peripheral presser, 8 is cavitation, 9 is a stamper outer peripheral suction device, throat 10 is a fixed mold, 11
Is a movable mold, and 12 is a sprue. The configuration itself of an (optical) disk substrate molding apparatus having a mold in which stampers 6 are mounted on both of two facing surfaces of a cavity as shown in FIG. 4 has been generally used since the era of analog records. , Never a new configuration. Also,
On the stamper 6 described above, the information to be mounted on the optical disc is engraved as a pit row, or a guide groove and an address for guiding a laser beam for additionally writing / rewriting information on the optical disc. Information is engraved. These pit rows or guide grooves are transferred onto the optical disc substrate 3 while the molten resin is filled in the cavity 5, cooled, and solidified to mold the optical disc substrate 3. Further, the transfer is required to be accurately transferred in order to obtain good information reading or write-once / rewrite characteristics.

However, the pit row or the guide groove engraved on the stamper 6 described above is extremely fine and minute as the amount of information to be mounted on the optical disk is increased. It is very difficult to accurately transfer these fine and dense pits onto the optical disc substrate 3. In addition, the optical disc on which more information is loaded has more strict characteristics in terms of shape characteristics such as warpage and waviness of the substrate 3 at the same time so that information can be stably read or additionally recorded / rewritten. It is required to be managed. These requirements make the molding of the optical disk substrate 3 very difficult.

For example, in order to accurately transfer the pit row or the guide groove, which is extremely fine and densified and which is difficult to transfer, onto the optical disk substrate 3, the temperature setting of the mold cavity 5 temperature control should be increased. You can set it to. However, when the cavity temperature control is increased, the optical disk substrate 3 to be molded is formed.
Shape characteristics such as warpage and undulation deteriorate. Regarding the deterioration of the shape characteristics described above, it is possible to avoid this by setting a longer cooling time after filling the cavity with the molten resin. However, if the cooling time is set longer, the time required to mold one optical disk substrate becomes longer,
Productivity will decrease.

As described above, with respect to the optical disc substrate used for the optical disc on which more information is loaded, the required transferability and other characteristics are ensured and the productivity is also kept good. It can be said that molding is extremely difficult. The present invention has been made in view of the above problems,

[0009]

In order to achieve the above object, a disk molding apparatus according to claim 1 of the present invention has a pair of stampers mounted on both surfaces facing each other in a cavity of a mold, and is required. In a disk molding apparatus for molding in which a fine shape is transferred to both sides of a molded product, by using an adiabatic stamper in which a heat insulating material is included in at least one of a pair of stampers, transferability required for a disk substrate and other It is possible to secure the above characteristics at the same time and mold the disk substrate with good productivity.

According to a second aspect of the present invention, there is provided the disc forming apparatus according to the first aspect, in which both the pair of stampers to be used are heat insulating stampers.
The molding conditions can be set more easily, and the warp shape characteristics of the disk substrate to be molded and its temporal stability are improved.

According to a third aspect of the present invention, there is provided a disk molding apparatus in which a pair of stampers are attached to both surfaces of a mold cavity that face each other, and a required fine shape is transferred to both surfaces of the molded product. Using a stamper having an annular or discontinuous recess forming a stack rib for preventing contact between the substrates when at least one of the pair of stampers to be used is loaded with the substrates molded by the molding apparatus. As a result, a production line with excellent mass productivity will be built.

According to a fourth aspect of the present invention, there is provided a disk forming apparatus in which a pair of stampers are mounted on both surfaces of a mold cavity that face each other, and a necessary fine shape is transferred to both surfaces of the molded product. Both of the pair of stampers to be used have a relatively fluidity by using a stamper having a recess forming a stack rib for preventing the substrates from contacting each other when the substrates molded by the above-mentioned molding apparatus are stacked on the surface. Enables substrate molding even with bad molding materials.

According to a fifth aspect of the present invention, there is provided the disc forming apparatus according to the third or fourth aspect, wherein the recess forming the stack rib on the molded substrate is a discontinuous recess, thereby preventing damage to the stamper. And extend the life of the stamper.

According to a sixth aspect of the present invention, there is provided the disc forming apparatus according to the third to fifth aspects, wherein the depth of the recess forming the stack rib on the molded substrate is less than ⅔ of the average plate thickness of the stamper. As a result, damage to the recess is prevented, and the life of the stamper is extended.

In the stamper manufacturing method according to the seventh aspect,
In the process of manufacturing a stamper for forming information transferred to a molded substrate, a block having a predetermined shape is provided on the cavity inner wall forming surface of a glass master, which is a master of the stamper, by a peelable fixing means, so that the concave portion can be easily formed. It shall have a shape.

In the block for fixing the glass master used in the stamper manufacturing method according to the eighth aspect, in the stamper manufacturing method of the seventh aspect, the mold releasability is improved in the conductive film forming region of the block fixed to the glass master. Due to the surface treatment, it has excellent mass productivity.

In the block for fixing the glass master according to claim 9, in the block for fixing the glass master according to claim 8, since the block is composed of an inclined surface having a large adhesive surface to the glass master, It shall have a concave shape that does not deteriorate the quality of the molded substrate.

In the disk molding apparatus according to the tenth aspect,
In the disk molding apparatus according to the second aspect of the present invention, the heat insulating effect of the pair of heat insulating stampers is changed so that the inner wall of the cavity has uniform thermal conductivity in the information forming area.

In the disk molding apparatus according to claim 11,
In the disk forming apparatus according to any one of claims 1 to 6, the other components constituting the inner wall surface of the cavity also have a heat insulating structure having a heat conduction blocking effect equivalent to that of the heat insulating stamper, so that the components other than the information forming area are provided. Also, the part (1) has the same thermal conductivity as that of the above region.

In the disk molding apparatus according to claim 12,
In the disk forming apparatus according to any one of claims 1 to 6, the heat insulating effect of the heat insulating structure given to the element forming the inner wall surface of the cavity is not uniform over the entire inner wall surface of the cavity, and varies depending on each position in the cavity. This creates an ideal temperature environment for the molded substrate.

In the stamper according to claim 13, claim 1
In the stamper used in the second disk molding apparatus, the heat insulation effect is changed in the radial direction to create an ideal temperature distribution environment in the actual use state.

According to the stamper of claim 14, claim 1
In the stamper of No. 3, the heat insulating material having the heat insulating effect has a film thickness distribution that becomes thicker toward the outer periphery in the radial direction, so that the heat insulating effect is easily changed.

In the stamper according to claim 15, claim 1
In the No. 4 stamper, the thickness of the heat insulating material in the outer peripheral portion relative to the thickness of the heat insulating material in the inner peripheral portion is relatively increased by 50 to 150 μm so that a predetermined temperature distribution is exhibited.

According to a sixteenth aspect of the present invention, in the method for producing a stamper according to the thirteenth or fourteenth aspect, after the heat insulating material layer is formed uniformly over the entire surface with the thickness of the heat insulating material, the polishing method is used. By forming the predetermined film thickness distribution, the heat insulating stamper having the predetermined film thickness distribution can be easily manufactured.

In the disk molding method according to the seventeenth aspect,
Any one of claims 1 to 6 or claims 10 to 1
By using the disc forming apparatus according to claim 2 or the stamper according to any one of claims 13 to 15,
A disk substrate having good characteristics can be molded with high productivity.

In the disk substrate according to the eighteenth aspect, by molding by the disk molding method according to the seventeenth aspect, it is possible to obtain a disk substrate having good characteristics and low cost.

According to a nineteenth aspect of the present invention, in the disk substrate according to the first aspect, the disk forming apparatus according to any one of the first to sixth aspects or the tenth to twelfth aspects is used, and the information forming stamper includes any one of the thirteenth to fifteenth aspects. By molding using the stamper, it is possible to obtain a molded substrate having a uniform groove-shaped transfer state from the inner circumference to the outer circumference.

A disc product according to a twentieth aspect can be obtained by using the disc substrate according to the eighteenth or nineteenth aspect to obtain a disc product having good characteristics and low cost.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. It should be noted that, in the following, the same parts as those in the prior art will be denoted by the same reference numerals, and overlapping description will be omitted. In the following description, an optical disc substrate of an optical disc having information surfaces on both sides will be described. However, a magnetic disc that uses another contact / non-contact method instead of a laser beam for reading or additionally writing / rewriting information,
The same applies to substrates of all disc products such as analog records and VHD discs.

In the following description, the optical disk substrate molding apparatus having the structure shown in FIG. 4 is used. The present invention uses a heat insulating stamper having a heat insulating structure in which a heat insulating material is included in at least one of the stampers 6 mounted on both of the two facing surfaces of the cavity 5.

Although not shown in FIG. 4, an enlarged shape of the inner peripheral portion of the heat insulating stamper 6 is shown in FIG. The inner peripheral portion of the surface of the stamper 6 is provided with a recess 15 as shown in the figure. The recess 15 forms the protrusion 14 having the same shape when transferred to the molded substrate (see FIG. 6). When the substrates 3 are stacked on each other, the protrusion 14 functions as a spacer as shown in FIG. 7, and protects the substrate surface from the contact between the substrates 3. As a result, the manufacturing line does not need a spacer, and a simple structure can be selected in terms of the line structure. Reference numeral 13 in the drawing is a mark of the stamper inner peripheral pressing member 7.

As shown in FIG. 8, the recess 15 may be annularly provided on the inner peripheral portion of the stamper. However, when molding is performed with such a stamper, at a certain number of shots,
The stamper itself was destroyed. This was found to be because the mechanical strength of the stamper itself was insufficient in the recess 15 provided in the stamper. As a countermeasure against this, in the present invention, an initially annular recess is provided as a discontinuous recess 15 on the stamper surface (see FIG. 9). As a result, the mechanical strength of the stamper as a whole was sufficiently ensured, and the same level of life as the conventional stamper could be achieved.

Next, the depth of the recess 15 will be described. Initially, the shape (depth) of the recess 15 was determined by paying attention to the shape of the stack rib formed on the substrate 3, that is, the shape of the protrusion 14. However, even after solving the above problems, further problems were found. It is a breakage of the concave portion 15. Although the strength of the stamper itself was secured, the recess 15
Damage was confirmed at the part, especially at the bottom. As a result of studying the depth of the recess 15 that can avoid this phenomenon, it was confirmed that it must be less than 2/3 of the stamper average plate thickness.

Next, the stamper having the recess 15 can be easily manufactured by the following method. FIG. 10 is a perspective view of the glass master 20 showing a state immediately before the formation of the conductive film before the electroforming step. A stack rib 14 formed on a surface of the glass master 20 has a predetermined shape, that is, a stack rib 14 formed on a molded substrate.
A block 21 in the shape of is bonded. The block 21 is made of metal or synthetic resin. Furthermore, a surface treatment for improving releasability, such as a Teflon (registered trademark) coat treatment, constitutes the cavity inner wall forming surface 20a on the surface thereof.

In this state, a conductive film is formed and put into the stamper manufacturing process similar to the conventional one. FIG. 11 is a diagram schematically showing the glass master after completion of electroforming. A metal film 23 is formed on the glass master 20 and is raised at a portion corresponding to the block 21 bonded to the surface of the glass master 20. As a next step, when the metal film 23 is peeled off from the glass master 20, the state shown in the schematic view of FIG. 12 is obtained. By polishing the back surface (including the protrusions 14) of the metal film 23 to a predetermined thickness by polishing, a stamper having a recess 15 on the stamper surface can be manufactured. In the figure, x indicates a portion to be removed by polishing.

Further, this block 21 is a glass master 2
It has a trapezoidal shape with a large portion bonded to 0. Initially, the block 21 was composed of a vertical surface having no inclined surface (see FIG. 13). When the substrate was molded with this concave shape, deterioration of the shape quality of the molded substrate was recognized. As a result of investigating the cause, it was found that the recess 15 for the stack rib provided on the inner peripheral portion of the stamper functions as a release resistance when the substrate 3 is peeled off, and as a result, the quality of the substrate shape is deteriorated. As a countermeasure, the glass master plate fixing block 21 has the shape shown in FIG. As is clear from the figure, a trapezoidal shape having a large adhesive surface with the glass master 20 was used. The shape of the recess of the stamper produced in this block 21 became the shape shown in FIG. 6, and there was no hindrance to the release from the stamper surface. As a result, a molded substrate with good shape accuracy was obtained.

Even in the molding apparatus equipped with the stamper which has been subjected to these methods, there were moldings in which problems occurred. It was molding with a molding material in which the fluidity was relatively poor. The molding material having poor fluidity may be dependent on the physical properties of the molding material itself, or may be a molding material having a different melting temperature. In such a case, the most noticeable change is incomplete transfer of the stack rib 14 shape. That is, when the stamper was manufactured, the intended shape accuracy could not be ensured, and when the stamper 31 was stacked (vertically stacked) on the pole stacker 30 or the like, the stacked state deteriorated. For example, it is a phenomenon in which the flatness of the uppermost substrate is disturbed (see FIG. 15).

This phenomenon is a phenomenon in which the influence is amplified by stacking stack ribs whose shape accuracy is deteriorated. In such a state, there is a problem in taking out a substrate by a robot arm designed on the premise of taking out a horizontally held substrate, and the operating rate of the production line is significantly reduced. In order to solve this problem, in the present invention, recesses 15 for stack ribs are formed on both surfaces of a pair of stampers. In addition, the depth of the recess 15 in that case was set to half the depth set when forming the recess on only one side. When the substrate was formed by this method, the rib shape accuracy did not deteriorate as described above, and as a result, the line could be operated without problems.

Now, when the molten resin 32 is filled into the cavity 5 from the sprue 12 at the center of the cavity 5, the molten resin 32 forms a contact surface with the inner wall surface of the cavity 5 from the moment when it starts flowing into the cavity 5. The heat which it has is conducted to the metal molds 10 and 11 through it and begins to cool. At that time, a solidified layer 33 called a skin layer is formed on the cavity contact surface of the molten resin (see FIG. 16). In the figure, 34 is a fluidized bed called a core layer, and 35 is a shear layer. The skin layer 33 has a property of inhibiting fine plastic deformation (transfer of fine shape) of the surface of the optical disk substrate to be molded, and in the case of molding that requires more precise and precise transfer, the skin layer 33 is required. Formation must be suppressed as much as possible. Therefore, in the usual method, the temperature control temperature for controlling the temperature around the cavity 5 is set to be high, but as described above, this method has a bad influence on the substrate shape characteristics other than the transferability, There is an adverse effect such as a decrease in productivity. In the present invention, the heat insulating stamper 40 is used in the portion where the pit row or the guide groove that requires precise transferability is transferred (see FIGS. 17A and 17B. FIG. 17C is a conventional example). Reference numeral 41 in the figure is a heat insulating layer. Therefore, in the portion where the precise transfer is required, the speed at which the molten resin 32 conducts heat to the molds 10 and 11 via the heat insulating stamper 40 becomes slow, and the formation of the skin layer 33 is suppressed. . This effect contributes to the lowering of the viscosity of the molten resin 32, and as a result, the molten resin 32 can maintain the flexibility capable of transferring a good fine shape. Further, due to this heat insulation effect, the cavity temperature control is set by the normal stamper 40.
It is possible to set the temperature lower than when using a. As a result, not only the shape characteristics such as warpage and waviness of the optical disk substrate to be molded become good, but also the molding cycle can be shortened and the productivity can be improved by lowering the cavity temperature control setting.

In the embodiment of the present invention, even if the heat insulating stamper 40 is used for only one of the two stampers used, the above-mentioned transferability, substrate shape characteristic improvement, and productivity improving effect by shortening the cycle are confirmed. did it. However, in order to correct the difference in heat conduction through the pair of stampers, it is necessary to set the temperature adjustment set temperatures of the heat insulating stamper side of the cavity and the normal stamper side to different optimum settings.
However, when the two stampers are both used as the heat insulating stamper 40, the heat conduction through both stampers can be balanced, so that not only the optimum temperature control can be easily set, but also the optical disc substrate to be molded can be The transferability, shape characteristics, and productivity can be further improved.

Further, in addition to the above-mentioned stamper, the heat insulating layer 42 is provided not only for the other elements constituting the inner wall surface of the cavity 5, for example, the stamper inner circumference pressing member 7 for fixing the stamper to the cavity, but also for insulating the heat insulating stamper 40. The heat insulating structure that gives the same effect as the effect is given (Fig. 1
8)), the effect of further improving the shape characteristics of the obtained optical disk substrate was obtained.

If the optical disc substrate is required to transfer a finer and finer shape with higher precision, and the shape characteristics are more rigorously defined, it is necessary to achieve uniform heat insulation of the entire inner wall surface of the cavity 5 as described above. It became clear that it was not possible to meet. Therefore, the thermal analysis from the behavior until the molten resin 32 flows into the cavity 5 and the whole is filled up to the completion of the cooling process is performed, and based on the result, the effect is changed depending on the position of the cavity 5, Specifically, when a heat insulating structure with a heat insulating layer 41 having a smaller heat insulating effect toward the center of the cavity 5 is applied to a stamper and other components to perform molding, an optical disk substrate that secures required characteristics can be manufactured with high productivity. It could be obtained without lowering (see FIG. 19).

A method of manufacturing the stamper heat insulating structure obtained as a result of the above flow analysis will be described below. The method is the same as the conventional method until the heat insulating layer 41 is formed inside the stamper.
However, the film thickness of the heat insulating layer formed at this time is set to the maximum in-plane film thickness required in the outer peripheral portion (see FIG. 20). Next, the additional processing stage of the heat insulating layer 41 is started. When the temperature distribution of the mold was confirmed, a temperature difference of about 10 ° C. was confirmed between the inner peripheral portion and the outer peripheral portion of the cavity 5. Naturally, the inner circumference is maintained at a higher temperature. In order to eliminate this temperature difference, the heat insulating layer 4
The film thickness of 1 was adjusted. It has been found that, when the numerical value is set to a thickness of 50 to 150 μm in the outer peripheral portion, based on the film thickness of the inner peripheral portion, a good result can be obtained. The width of this numerical value is a numerical value determined by the shape of the groove transferred to the molded substrate. With a stamper using a metal thin film as a recording film, the effect was sufficiently obtained with a film thickness difference of about 50 μm. Further, a stamper using an organic film as a recording film requires a film thickness difference of about 150 μm. The polishing method was most suitable as a concrete method. The entire surface of the stamper is polished to a film thickness suitable for the groove shape to which the heat insulating layer 41 formed in the outer peripheral portion is formed (see FIG. 21). In the figure, 43 is a polishing tool. The resulting heat insulating stamper 40 in the process of manufacture is in the state shown in FIG. This stamper 40 is electroformed again to complete a stamper having a predetermined plate thickness. When the heat insulating layer having the film thickness distribution is electroformed, a stamper having a plate thickness distribution following the film thickness distribution of the heat insulating layer 41 is obtained as shown in FIG. 23. From this state, the stamper surface ( The heat insulating stamper 4 having a uniform thickness distribution and having a film thickness gradient of the heat insulating layer by polishing the back surface based on the information recording surface).
0 (see FIG. 24) can be easily manufactured.

By using this stamper, a substrate with good groove transfer was obtained. The molded substrate, in which the effect was particularly remarkable, was a medium in which an organic thin film was formed on the substrate by spin coating. When the organic thin film is formed by spin coating, that is, a liquid coating method, a relatively deep groove needs to be formed on the substrate because the organic film tends to be deposited more in the groove on the substrate. On the other hand, since the temperature distribution of the molding die is such that the heat radiation is larger toward the outer periphery of the die, the temperature distribution of the inner wall of the cavity 5 tends to be correspondingly lower toward the outer periphery. This temperature gradient is based on the above-mentioned skin layer 3
3 is greatly affected. In the experiment conducted by the inventor of the present application, when the depth of the groove exceeds 1500 Å, the tendency of the groove transfer to deteriorate in the outer peripheral portion starts to be recognized due to the influence of the temperature gradient. When this problem was molded with a mold having an inner wall of the cavity with a change in the heat insulation effect, a substrate having a uniform groove transfer state was obtained. The characteristics of the optical disk manufactured by using the optical disk substrate thus obtained, especially the characteristics of the organic thin film type recording medium having a relatively deep groove, were good, and the cost thereof was kept low.

[0045]

As described above, in the disk molding apparatus according to the first aspect of the present invention, a pair of stampers are mounted on both surfaces of the mold cavity that face each other, and a necessary fine shape is formed on both surfaces of the molded product. In a disk molding apparatus that performs transfer molding, by using a heat insulating stamper in which a heat insulating material is included in at least one of a pair of stampers, the transferability and other characteristics required of the disk substrate are secured at the same time, and The disk substrate could be molded with good productivity.

As described above, the disk molding apparatus according to the second aspect of the present invention makes it easier to set molding conditions by using a heat insulating stamper for both the pair of stampers used in the disk molding apparatus of the first aspect. so,
It was possible to provide a molding apparatus in which the warped shape characteristics of the molded disk substrate and the temporal stability thereof are also good.

As described above, the disk molding apparatus according to claim 3 is the disk molding apparatus according to claim 1 or 2, in which a pair of stampers is mounted on both surfaces of the mold cavity facing each other, and is required. In a disk molding device that performs molding to transfer a fine shape to both sides of a molded product, when the substrates molded by the molding device are stacked on at least one stamper surface of a pair of stampers to be used, contact between the substrates is prevented. By using a stamper having an annular or discontinuous concave portion that forms a stack rib to prevent, a production line excellent in mass productivity could be constructed.

As described above, the disk molding apparatus according to claim 4 is the disk molding apparatus according to claim 1 or 2, in which a pair of stampers is mounted on both surfaces of the mold cavity facing each other, and is required. In a disk molding apparatus that performs molding to transfer both fine shapes to both sides of a molded product, both of a pair of stampers to be used are stacks for preventing contact between the boards when the substrates molded by the molding apparatus are stacked on the surfaces. By using a stamper having a concave portion for forming a rib, it is possible to provide a molding apparatus that enables molding of a substrate even with a molding material having relatively poor fluidity.

As described above, the disk forming apparatus according to a fifth aspect of the present invention is the disk forming apparatus according to the third or fourth aspect, wherein the recess forming the stack rib on the molded substrate is a discontinuous recess. As a result, it was possible to prevent the stamper from being damaged and provide a stamper having a long life.

As described above, the disk molding apparatus according to a sixth aspect of the present invention is the disk molding apparatus according to any one of the third to fifth aspects, wherein the depth of the recessed portion forming the stack rib on the molded substrate is the stamper. By setting the average plate thickness to be less than ⅔, it is possible to provide a stamper having a long service life by preventing breakage in the recess.

In the stamper manufacturing method according to the seventh aspect,
The disc molding apparatus according to any one of claims 3 to 5, wherein in a step of manufacturing a stamper for forming information transferred to a molded substrate, a fixing means that can be peeled off from a cavity inner wall forming surface of a glass master serving as a master of the stamper. By providing a block having a predetermined shape, it becomes possible to easily have a concave shape.

In the block for fixing a glass master according to claim 8, in the stamper manufacturing method according to claim 7, the conductive film forming region of the block fixed to the glass master is subjected to a surface treatment for improving releasability. As a result, it was possible to achieve excellent mass productivity.

In the block for fixing the glass master according to claim 9, in the block for fixing the glass master according to claim 8, since the block is composed of an inclined surface having a large adhesion surface to the glass master, It was possible to have a recessed shape in which the quality of the molded substrate did not deteriorate.

In the disk forming apparatus according to the tenth aspect,
In the disk molding apparatus of the second aspect, the thermal conductivity of the information forming area can be made uniform on the inner wall of the cavity by changing the heat insulating effect of the pair of heat insulating stampers.

In the disk molding apparatus according to claim 11,
In the disk molding apparatus according to any one of claims 1 to 6, also with respect to other elements constituting the inner wall surface of the cavity,
By providing the heat insulating structure having the same heat conduction blocking effect as that of the heat insulating stamper, it was possible to make the portions other than the information forming area have the same thermal conductivity as the above area.

In the disk molding apparatus according to claim 12,
In the disk forming apparatus according to any one of claims 1 to 6, the heat insulating effect of the heat insulating structure given to each element forming the inner wall surface of the cavity is not uniform over the entire inner wall surface of the cavity, and changes depending on each position in the cavity. By doing so, it was possible to create an ideal temperature environment for the molded substrate.

In the stamper according to claim 13, claim 1
In the stamper used in the disk molding apparatus of No. 2, the heat insulating effect of the heat insulating stamper was changed in the radial direction, so that an ideal temperature distribution environment could be obtained in an actual use state.

In the stamper according to claim 14, claim 1
In the heat insulating stamper of No. 3, since the heat insulating material of the heat insulating stamper having a heat insulating effect has a film thickness distribution that becomes thicker toward the outer periphery in the radial direction, a heat insulating stamper whose heat insulating effect changes easily can be obtained. did it.

In the stamper according to claim 15, claim 1
In the heat insulating stamper of No. 4, the heat insulating material film thickness of the outer peripheral portion relative to the heat insulating material film thickness of the inner peripheral portion is 50 to 150 μm.
s that shows a predetermined temperature distribution by increasing the thickness
We were able to.

According to a sixteenth aspect of the present invention, in the method of manufacturing a stamper according to the thirteenth or fourteenth aspect, first, a heat insulating layer is formed uniformly over the entire thickness of the heat insulating material in the outer peripheral portion, and then a predetermined film is formed by a polishing method. By forming the thickness distribution, a heat insulating stamper having a predetermined thickness distribution can be easily manufactured.

In the disk molding method according to the seventeenth aspect,
Any one of claims 1 to 6 or claims 10 to 1
By using the disc forming apparatus according to claim 2 or the stamper according to any one of claims 13 to 15,
A disk substrate having good characteristics could be molded with high productivity.

According to the disk substrate of the eighteenth aspect, by molding by the disk molding method of the seventeenth aspect, a disk substrate having good characteristics and low cost can be obtained.

According to a nineteenth aspect of the present invention, the disc substrate according to any one of the first to sixth aspects or the tenth to twelfth aspects is used for the disc substrate, and the information forming stamper includes the thirteenth to fifteenth aspect. By molding using the stamper, it was possible to obtain a molded substrate having a uniform groove-shaped transfer state from the inner circumference to the outer circumference.

The disc product according to claim 20 was manufactured by using the disc substrate according to claim 18 or 19, whereby a disc product having good characteristics and low cost could be obtained.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a conventional optical disc.

FIG. 2 is a sectional view of a surface recording type optical disc.

FIG. 3 is a cross-sectional view of a front surface recording type double-sided optical disk.

FIG. 4 is a sectional view showing a basic structure of an optical disk substrate molding apparatus.

5 is a sectional view showing a stamper fixing structure of the apparatus of FIG.

6 is a sectional view of a molded substrate molded by the apparatus of FIG.

FIG. 7 is a cross-sectional view showing a state where the molded substrates of FIG. 5 are stacked.

8 is an enlarged plan view (A) and an AA cross-sectional view (B) of the inner peripheral portion of the heat insulating stamper used in the apparatus of FIG.

9 is an enlarged plan view (A) and a sectional view (B) taken along the line BB of the inner peripheral portion of the heat insulating stamper of the embodiment of the present invention used in the apparatus of FIG. 4.

FIG. 10 is a perspective view of a glass master according to the embodiment of the present invention.

11 is an enlarged cross-sectional view of the glass master shown in FIG.

FIG. 12 is a perspective view (A) and a sectional view taken along the line CC of FIG. 10 showing a stamper manufacturing process using the glass master disk of FIG. 10;

FIG. 13 is a cross-sectional view showing a block for forming stack ribs on a glass master.

FIG. 14 is a cross-sectional view showing a block for forming stack ribs on a glass master.

FIG. 15 is a side view showing a state where the manufactured stamper is loaded on the pole stacker.

FIG. 16 is a cross-sectional view showing a molten resin flowing in a cavity.

FIG. 17 is a cross-sectional view (A) of the heat insulating stamper of the present invention and a cross-sectional view (B, C) of a temperature state by the heat insulating stamper.

FIG. 18 is a sectional view showing the structure of another example of the optical disk substrate molding apparatus of the present invention.

FIG. 19 is a cross-sectional view of another example of the heat insulating stamper of the present invention.

20 is a cross-sectional view showing the manufacturing process of the heat insulating stamper of FIG.

FIG. 21 is a cross-sectional view showing a manufacturing process of the heat insulating stamper of FIG. 19.

22 is a cross-sectional view showing the manufacturing process of the heat insulating stamper of FIG.

FIG. 23 is a cross-sectional view showing the manufacturing process of the heat insulating stamper of FIG. 19.

FIG. 24 is a cross-sectional view showing the manufacturing process of the heat insulating stamper of FIG. 19.

[Explanation of symbols]

1, 1a, 1b optical disc 2 Information side 3 Optical disc substrate 4 cover layers 5 Cavity 6 Stamper 7 spool 8 Stamper inner circumference presser 8 cavilling 9 Stamper peripheral suction mechanism 10 Fixed mold 11 movable mold 12 sprue 14 Projection (stack rib) 15 recess 20 glass master 21 blocks 23 Metal film 30 pole stacker 31 Stamper 32 molten resin 40 Insulation stamper 41, 42 heat insulation layer L laser beam

Continued front page    F-term (reference) 4F202 AG28 AH38 AH79 CA11 CB01                       CD02 CK06 CK28                 4F206 AG28 AH38 AH79 JA07 JQ81                 5D121 BA05 BB05 CA01 CA10 DD05                       DD18 GG22

Claims (20)

[Claims] 1. A disk molding apparatus for mounting a pair of stampers on opposite surfaces of a cavity of a mold to transfer a required fine shape to both surfaces of a molded product, and at least one of the pair of stampers. A disk molding apparatus, characterized in that a heat insulating stamper including a heat insulating material is used on one side. 2. The disk molding apparatus according to claim 1, wherein
A disk molding apparatus, wherein heat insulating stampers are used for both of the pair of stampers. 3. The disc molding apparatus according to claim 1, wherein a stack rib is formed on at least one surface of the pair of stampers to prevent contact between the substrates when stacking the molded substrates. A disk molding device having a recess. 4. The disk molding apparatus according to claim 1 or 2, wherein recesses are formed on both surfaces of the pair of stampers for forming stack ribs for preventing contact between the molded substrates when they are stacked. A disk molding device characterized by having. 5. The disk molding apparatus according to claim 3 or 4, wherein a plurality of recesses for forming the stack ribs are discontinuously provided. 6. The disk molding apparatus according to claim 3, wherein the depth of the recess for forming the stack rib is less than ⅔ of the average plate thickness of the stamper. . 7. A method of manufacturing a stamper, which is used in the disk molding apparatus according to claim 3 to form information transferred to a molded substrate, and is capable of being peeled onto a cavity inner wall forming surface of a glass master serving as a master of the stamper. A method of manufacturing a stamper, characterized in that a block having a predetermined shape is provided by various fixing means. 8. The glass master fixing block used in the stamper manufacturing method according to claim 7, wherein the conductive film forming region is subjected to a surface treatment for improving releasability. Blocks. 9. The block for fixing a glass master according to claim 8, wherein the block for fixing the glass master is constituted by an inclined surface having a large adhesion surface to the glass master. 10. The disk molding apparatus according to claim 2, wherein the pair of stampers have different heat insulating effects. 11. The disk forming apparatus according to claim 1, wherein the other components forming the inner wall surface of the cavity also have a heat insulating structure having a heat conduction blocking effect equivalent to that of the heat insulating stamper. Characteristic disk forming device. 12. The disk forming apparatus according to claim 1, wherein the heat insulating effect of the heat insulating structure applied to the elements forming the inner wall surface of the cavity is not uniform over the entire inner wall surface of the cavity, and A disk forming apparatus, which is different at each position. 13. The stamper used in the disk forming apparatus according to claim 12, wherein the heat insulating effect is changed in the radial direction. 14. The stamper according to claim 13, wherein a film thickness of the heat insulating material having a heat insulating effect has a film thickness distribution which becomes thicker toward the outer periphery in the radial direction. 15. The stamper according to claim 14, wherein the thickness of the heat insulating material at the outer peripheral portion is relatively thicker than that of the heat insulating material at the inner peripheral portion by 50 to 150 μm. 16. The stamper manufacturing method according to claim 13 or 14, wherein a layer of the heat insulating material is formed uniformly over the entire surface of the heat insulating material, and then a predetermined thickness distribution is formed by a polishing method. A method for manufacturing a stamper, characterized by: 17. A disk molding method using the disk molding apparatus according to any one of claims 1 to 6 or any one of claims 10 to 12 or the stamper according to any one of claims 13 to 15. 18. A disk substrate formed by the disk forming method according to claim 17. 19. A disk molding apparatus according to any one of claims 1 to 6 or any of claims 10 to 12 is used, and an information forming stamper is formed by using the stamper according to any one of claims 13 to 15. A disk substrate characterized by being formed. 20. A disc product manufactured by using the disc substrate according to claim 18 or 19.