JP4680132B2 - Disc manufacturing method, disc recording medium - Google Patents

Description

  The present invention relates to a disc recording medium manufacturing method in which one surface is a label printing surface and the other surface is an information reading surface on which pits and grooves are formed, and the disc recording medium to be manufactured.

JP 2004-30830 A

In the optical disk manufacturing process, resin-molded disk substrates are often stacked and stored and transported on poles.
For example, as shown in FIG. 12, a substrate carrier 30 having a storage shaft 31 is used, and the center hole of the disk substrate 1 being manufactured is passed through the storage shaft 31, so that a large number of disk substrates 1 are stacked. Store and transport to the next process.

  The discs that are stacked and transported in this way are picked up and processed one by one in the next process, but this causes a problem that the transporter that should handle one by one transports two at a time. It has been known. This is also called “two-sheet picking”, and is a problem that occurs because the stacked disks stick together.

An annular projection called a protection ring is provided in the vicinity of the innermost periphery of the disk substrate in order to prevent the two sheets from being picked up and to prevent the surfaces of the disk substrates from being damaged by overlapping each other. May be.
FIG. 13 shows a cross-sectional structure of the disk substrate 101 during the manufacturing process. The disk substrate 101 is made of, for example, polycarbonate resin, and its center is a center hole 104. One surface of the disk substrate 101 is a label printing surface 102 and the other surface is an information reading surface 103. In FIG. 13, a pit pattern 103a on which information is recorded is formed on the information reading surface 103 side of the disk substrate 101, and a layer structure 106 such as a reflective layer, a cover layer, and a hard coat is formed on the pit pattern side. Yes.
A protection ring 105 is formed around the center hole 104.

For example, the disk substrates 101 at such a stage are stacked on the substrate carrier 30 in FIG.
At this time, the protection ring 105 and the label printing surface 2 are in contact with each other on the disk substrates 101 to be stacked. That is, by preventing the label printing surface of one disk substrate 101 and the information reading surface 103 of the overlapped disk substrate 101 from being in close contact with each other by the protection ring 105, it is possible to prevent the disk substrates from sticking together. Thus, protection of the information reading surface 103 is expected.

  However, in the case of a Blu-ray Disc (registered trademark), for example, the height of the protection ring 105 is determined to be lower than 0.12 mm from the reference surface (the surface of the information reading surface 103). Therefore, the protection ring 105 cannot be made high enough to prevent sticking. In particular, among the large number of stacked disk substrates 101, the outer peripheral portions are likely to be in close contact with each other in the disk substrates positioned on the substrate transport table 30. For this reason, especially in the case of the disk substrate 101 that has not been cooled immediately after being formed, the protection ring 105 often cannot sufficiently perform the sticking prevention function, and in some cases, it is not possible to avoid taking two sheets.

In addition, Patent Document 1 discloses that a protection ring (stack rib) is formed on the label printing surface side, and the top surface of the protection ring is roughened. However, the height of the protection ring is sufficient. If it cannot be removed, the sticking prevention effect may not be sufficiently obtained.
Also, since the label printing surface is required to be printed as cleanly as possible in the widest possible area, forming convex portions such as protection rings on this label printing surface will reduce the commercial value of the disc and is difficult to implement There are also circumstances.

  For these reasons, the printing effect on the label printing surface is not impaired, and even if the protection ring on the information reading surface side is low (or even if there is no protection ring), it will not cause sticking in the manufacturing process. The present invention proposes a disc manufacturing process and a disc recording medium that can meet such a demand.

The disk manufacturing method of the present invention is a disk recording medium manufacturing method in which one side is a label printing surface and the other side is an information reading surface. A substrate generating step for generating a disc substrate having an uneven pattern on the information reading surface side and a satin-like surface having a maximum roughness of more than 0.5 μm and 5 μm on the label printing surface side; A layer forming step of forming a layer on the information reading surface side, and a storage step of stacking and storing a plurality of disk substrates that have undergone the layer forming step.
Furthermore, after taking out each disk board | substrate with which the several sheets were piled up by the said storage process, you may provide the printing process which prints on the said label printing surface side of a disk board | substrate.
Further, in the substrate generating step, the disk substrate is formed using a mold in which the inner surface corresponding to the label surface side of the disk substrate is a matte surface having a maximum roughness in a range from 0.5 μm to 5 μm. Generate.
In this case, it is assumed that the matte surface of the mold is a surface formed by colliding a substantially spherical object by blasting.
In the layer forming step, a moisture-proof film is further formed on the label printing surface having a satin finish.

The disc recording medium of the present invention is a disc recording medium in which one side is a label printing surface and the other side is an information reading surface, and the label printing surface side has a satin finish having a maximum roughness of more than 0.5 μm. In this case, the disk substrate is formed in a satin shape with a substantially spherical collision shape within a range of up to 5 μm, and is formed by forming a layer on the information reading surface side of the disc substrate having the unevenness pattern on the information reading surface side.
Further, a moisture-proof film is formed on the label printing surface side of the satin-like disk substrate, and printing is performed.

When multiple disc substrates are stacked, the satin-like label printing surface of one disc substrate and the signal reading surface of the other disc substrate are in contact, but the label printing surface is matte. Thus, it is possible to almost completely prevent the disk substrates from sticking to each other.
“Nashiji” refers to a state in which fine irregularities are uniformly formed on the surface by mechanical or scientific treatment as defined in JIS (Japan Industrial Standard) (“pear finish”).
The maximum roughness of the satin is 0.5 μm to 5 μm, but 0.5 μm is the minimum roughness for obtaining the sticking prevention effect, and 5 μm is the aesthetic appearance of the label surface after the printing process. The maximum roughness is maintained.
In addition, a moisture-proof film was formed when the pear surface on the disk substrate was manufactured with a mold having a pear ground formed by colliding a substantially spherical object by blasting to a pear-like surface with a substantially spherical collision shape. The appropriate moisture-proof effect can be exhibited.

Since the label printing side of the disk substrate has a satin finish, many disk substrates are stacked and stored in the storage process, and when they are transported, the stacked disk substrates are stuck together. For this reason, when taking out the disk substrates one by one in the next step, “two picks” do not occur. This has the effect that efficient disk manufacture can be performed.
Also, on the side of the label printing surface that is made into a satin-like shape, in the printing process, for example, the white surface is flattened with a white coat, and printing is performed, so that the same aesthetic appearance as in the case of a normal flat surface-like label printing surface is obtained. Can maintain product value.

  Furthermore, by making the satin surface of the disk substrate into a satin surface having a substantially spherical collision shape, an appropriate moisture-proof effect when a moisture-proof film is formed can be exhibited, thereby suppressing warping of the disk substrate.

An embodiment of the disk manufacturing method of the present invention will be described. FIG. 1 shows the steps of the disk manufacturing method according to the embodiment, which will be described along these steps.
The disk manufacturing method of the embodiment includes a substrate forming process in step F101, a reflective film forming process in step F102, a cover layer forming process in step F103, a hard coat process in step F104, an inspection process in step F105, and a storage process in step F106. And a label printing process of step F107.

In the substrate forming process of step F101, a disk substrate is formed in which one surface is a label printing surface and the other surface is an information reading surface. At this time, the entire surface (or almost the entire surface) of the label printing surface of the disk substrate is made into a satin finish.
Disc substrate molding is performed by injection molding of polycarbonate resin. FIG. 2 (a) schematically shows a mold for molding a disk substrate. This mold is composed of a lower cavity 20 and an upper cavity 22, and a stamper 21 for transferring information pits is disposed in the lower cavity 20. The stamper 21 is formed with an uneven pattern 25 of information pits and a ring-shaped recess 24 for forming a protection ring as a ring-shaped region on the inner peripheral side of the disc.
In the manufacturing process of the read-only disk, the stamper 21 having the uneven pattern 25 of information pits is disposed as the embossed pit. In the manufacturing process of the recordable disk (for example, write-once disk or rewritable disk), the recording track A stamper on which a concavo-convex pattern for forming a groove (wobbling groove) is formed is disposed.

In addition, the upper cavity of the mold has a matte surface 23 that forms the label printing surface side of the disk substrate.
The pear ground 23 can be formed by etching or a blaster method in which alumina, glass beads, plastic beads or the like collide.
As shown in FIG. 2B, the pear surface of the pear ground 23 has a maximum roughness as the size of the most uneven portion of the unevenness, for example, in the range of 0.5 μm to 5 μm. In practice, the thickness is preferably 2 to 3 μm.

The disk substrate 1 is formed by injection molding using such a mold, and the formed disk substrate 1 is as shown in FIG.
That is, the center of the disk substrate 1 made of polycarbonate resin is the center hole 4, and the information reading surface 3 side is a pattern of information pits 3a to which the unevenness formed on the stamper 21 in the mold is transferred. In some cases, not information pits but grooves (continuous grooves) are formed. A ring-shaped convex portion as a protection ring 5 is formed around the center hole 4 on the inner peripheral side.
Further, the label printing surface 2 side of the disk substrate 1 is a pear ground 11 to which a pear ground 23 of a mold is transferred. That is, the label printing surface 2 is a textured surface having a maximum roughness of, for example, 0.5 μm to 5 μm (for example, 2 to 3 μm).

The disk substrate 1 thus formed is formed with a layer structure on the signal reading surface 3 side in steps F102, F103, and F104. 4A and 4B show the layer structure in a state where the process proceeds to Step F104. FIG. 4B is an enlarged view of the layer structure on the signal readout surface 3 side.
First, in step F102, a reflective film 7 made of, for example, an Ag alloy is formed on the signal reading surface 3 side where the information pit pattern is formed.
Next, in Step F103, the cover layer 6 is formed by a technique such as pasting of a polycarbonate film or spin coating with an ultraviolet curable resin.
In step F104, the hard coat layer 8 is formed as a surface treatment on the signal readout surface 3 side. The hard coat layer 8 may not be formed.

  Through the above steps, the necessary layer formation is completed on the signal readout surface 3 side. The disk substrate 1 that has undergone the above steps is subjected to quality check in the inspection step of Step F105. In step F106, the disc substrate 1 as an acceptable product is stored in a state of being stacked on the substrate transport table 30 shown in FIG. 12, and transported to the next process.

The large number of disk substrates 1 stacked and conveyed on the substrate conveyance table 30 are then taken out one by one and printed on the label printing surface 2 side in the printing process of step F107.
In this printing process, as so-called offset printing, a white coat is applied to the entire surface on the label printing surface 2 side, which is made into a satin finish, and then, for example, color printing is performed, and a printing layer 9 is formed as shown in FIG. It is formed. Thereby, the label printing surface 2 side after printing becomes a flat printing surface on which the matte surface 11 is not exposed.

In the disk manufacturing process described above, the label printing surface 2 side of the disk substrate 1 has a satin finish, so that even if a large number of disk substrates are stacked and stored on the substrate transport table 30 in step F106, they are stacked vertically. There is no sticking of the disk substrates. This is because the satin-like label printing surface 2 lowers the adhesion with the signal reading surface 3 of the disk substrate 1 stacked thereon.
In particular, when the maximum roughness of the satin is about 2 to 3 μm (at least 0.5 μm or more), the sticking prevention effect can be obtained satisfactorily.
For this reason, when taking out the disk substrates one by one in the next printing process, “two-sheet picking” does not occur, and efficient disk manufacture can be realized.

Further, on the label printing surface 2 side that is in a satin-like shape, the label printing surface 2 side of the disc substrate 1 is made a satin-like shape in the printing process by flattening the pear ground 11 with a white coat in the printing process. As with normal disk substrates, the aesthetic appearance of a flat printed surface can be maintained, so that the commercial value is not impaired.
In particular, since the maximum roughness of the satin is about 2 to 3 μm (at least 5 μm or less), it is possible to easily flatten the label printing surface 2 with a white coat.
The white coat is also carried out in the normal printing process to obtain good color development and fixing properties of the ink during printing, and is especially executed to fill the pear ground 11 in this example. Not what you want. That is, in this example, the labor of the printing process is not increased.

  In this example, the disk substrate 1 having the protection ring 5 is taken as an example, but the protection ring 5 is formed at a height of 0.12 mm or less from the surface of the signal reading surface 3 which is a reference surface, for example. Yes. Such a protection ring 5 is particularly effective as a protection function for the signal reading surface 3 between the stacked disk substrates 1, but does not sufficiently function to prevent sticking. The sticking prevention effect is only due to the satin-like label printing surface 2. Therefore, for example, depending on the material of the signal reading surface 3 (hard coat layer 8), the protection ring 5 may not be formed if a protective function is not required so much.

  By the way, the label printing surface 2 side of the disk substrate 1 is the pear surface 11, in other words, the inner surface of the upper cavity 22 of the mold (the inner surface corresponding to the label surface side of the disk substrate) is pear as shown in FIG. By using the ground 23, the effect of improving the accuracy of forming pits formed on the signal reading surface 3 side can be obtained. This will be described.

For recording pit formation of CD (Compact Disc) and DVD (Digital Versatile Disc), accurate transfer of stamper pit patterns is required, and high-precision molding technology is required.
Here, in the Blu-ray Disc (registered trademark), which is a higher density optical disc developed recently, the track pitch of the pit row is 0.32 μm, which is about half that of a DVD. The width, length, and depth of the plate are also small. Therefore, when a disc substrate is molded using a stamper, pit deformation (hereinafter referred to as pit deviation) on the molded substrate is likely to occur, and a slight amount Even a slight pit shift will greatly affect the reproduction signal.

FIG. 6 shows the state of pit shift. FIG. 6A shows an example in which pits 3a are normally formed when a disk substrate is manufactured using a stamper.
However, especially on the inner circumference side of the disc, a pit shift occurs in the shape of the pit 3a flowing on the inner circumference side as shown in FIG. 6B, or as shown in FIG. 6C on the outer circumference side of the disc. A pit shift is likely to occur as if the pit 3a flowed on the outer peripheral side.
This pit shift depends on the adhesion between the stamper and the disk substrate during molding. For example, if the adhesion between the stamper and the disk substrate is weak, pit displacement tends to occur when the resin is cooled in the mold and when the clamping force is released. On the other hand, if the adhesion is too strong, pit deviation is likely to occur when the disk substrate is peeled from the stamper.
Therefore, moderate adhesion is required. However, if the size of the pit itself is reduced as in a high-density optical disk such as a Blu-ray disc, it is difficult to obtain sufficient adhesion between the stamper and the disk substrate during molding. Deviation tends to occur.

Here, in the case of this example, the label printing surface 2 which is the other surface with respect to the information reading surface 3 on which the information pits 3a are formed on the disk substrate 1 as described above is made to be a matte surface 11. That is, the inner surface of the upper cavity 22 of the mold is a matte surface 23. As a result, appropriate adhesion can be obtained when the disk substrate 1 is molded by the molds (20, 22) and the stamper 21, and shrinkage when the resin is cooled in the mold and release of the clamping force. There is an effect that sometimes prevents pit shift. That is, a normal pit 3a as shown in FIG. 6A can be formed over the entire circumference of the disk.
Actually, in the read-only optical disc formed in this way, when it was reproduced and jitter was measured, a good result of 5.5% or less over the entire circumference of the disc was obtained. That is, the deterioration of the reproduction signal characteristics due to the pit shift was not recognized. Further, in order to confirm the molding stability, even when 10000 sheets were continuously molded, the jitter was not deteriorated even when the sampling evaluation was performed.
Thus, the occurrence of pit deviation can be prevented and the pit transfer accuracy can be improved, so that the manufactured optical disk can be an optical disk with stable reproduction signal characteristics.
As a result of confirmation by actual production, it was found that the maximum roughness of the satin texture is preferably 0.5 μm or more in terms of not only the above-mentioned sticking prevention effect but also prevention of pit shift.

By the way, in the description of the process of forming the cover layer 6 in step F103 in FIG. 1, it has been described that the cover layer 6 is formed by a technique such as pasting a polycarbonate film or spin coating with an ultraviolet curable resin.
Here, depending on whether the cover layer 6 formed on the signal reading surface 2 side of the polycarbonate disk substrate 1 is formed of the same material (polycarbonate) as the disk substrate 1 or a different material (ultraviolet curable resin), Different circumstances arise.

7A and 7B schematically show the disk layer structure in which the hard coat layer 8 is formed as shown in FIG. 4A by the manufacturing process, that is, steps F101 to F104. FIG. 7A shows an example in which a cover layer 6 made of a polycarbonate material is formed on a polycarbonate disk substrate 1. FIG. 7B shows an example in which a cover layer 6 made of an ultraviolet curable resin is formed on a polycarbonate disk substrate 1.
For example, in the state of FIG. 7 (a) or FIG. 7 (b), the disk substrate 1 proceeds to the inspection, storage, and transport process. In the case of FIG. 7 (b), the warpage of the disk substrate 1 is performed. Problems are likely to occur.

When the disk substrate 1 and the cover layer 6 are made of the same material as shown in FIG. 7 (a), since the moisture absorption amount of each layer is equal, the warp does not occur so much, but the disk as shown in FIG. 7 (b). When the substrate 1 and the cover layer 6 are made of different materials, a relatively large warp is likely to occur due to the difference in the amount of moisture absorption, and there are many discs that cannot be used, that is, a disc whose warp amount becomes too large, resulting in a production yield. Is significantly worse.
Therefore, when the disc substrate 1 and the cover layer 6 are made of different materials as shown in FIG. 7B, the moisture-proof film 10 is formed on the label printing surface 2 side of the disc substrate 1 as shown in FIG. 7C. It is possible to do. For example, as the moisture-proof film 10, an inorganic oxide film or the like is formed by sputtering.

However, as described above, when the label printing surface 2 side of the disk substrate 1 is the matte surface 11 in order to prevent sticking and improve pit transferability, the moisture-proof film 10 having a necessary thickness is effectively formed on the surface. It is difficult to do.
As the moisture-proof film 10, for example, SiO ₂ needs to be formed in a thickness of about 50 to 100 nm. However, the moisture-proof film 10 is uniform in the pear ground 11 formed by a usual blaster made of alumina depending on the micro-inclination of the surface and the situation. Thus, the moisture-proof function is impaired and the disk substrate 1 is warped.

Here, the situation of the pear ground (the pear ground 23 of the upper cavity 22 of the mold and the pear ground 11 of the disk substrate 1) is considered. FIGS. 8A and 8B schematically show the state of the pear ground 11 formed on the disk substrate 1.
FIG. 8A shows a case where the pear ground 23 of the upper cavity 22 of the mold is formed by blasting using spherical glass beads as shown in FIG. 9A, and FIG. The case where the pear ground 23 of the upper cavity 22 of the mold is formed by blasting using alumina which is not a substantially spherical body as in b) is shown respectively.
When a spherical body as shown in FIG. 9A (or a substantially spherical body such as an elliptical sphere) is used in blasting, the surface of the pear ground 11 (pear ground 23) as shown in FIG. 8A. It becomes a gentle state. On the other hand, when blasting is performed using alumina with a sharp surface as shown in FIG. 9B, the surface of the pear ground 11 (pear ground 23) is sharp as shown in FIG. 8B. It will be like standing upright.

According to the experiment, it was confirmed that the effect of the moisture-proof film 10 varies depending on the difference in the pear ground 11.
That is, when the pear ground 23 is formed on the mold by blasting using alumina as shown in FIG. 8B and transferred as the pear ground 11 of the disk substrate 1, as shown in FIG. 7C. Even if the moisture-proof film 10 is formed, the moisture-proof effect, that is, the warp-preventing effect is not sufficiently obtained, but a surface formed by colliding a substantially spherical object as shown in FIG. 8A (substantially spherical object collision shape). As shown in FIG. 7C, a sufficient moisture-proof effect can be obtained and the warp of the disk substrate 1 can be prevented.

Therefore, when the disk substrate 1 and the cover layer 6 are formed of different materials, such as when an ultraviolet curable resin is used for the cover layer 6, the manufacturing process is performed as shown in FIG. 10.
In this case, the disk manufacturing method includes a substrate forming process in step F201, a reflective film forming process in step F202, a cover layer forming process in step F203, a hard coat process in step F204, a moisture-proof film forming process in step F205, and an inspection in step F206. A process, a storage process in step F207, and a label printing process in step F208.

In the substrate molding process of Step F201, the disk substrate 1 having the label printing surface 2 side of the pear surface 11 is manufactured by injection molding of polycarbonate resin. The pear on the inner surface side of the upper cavity 22 of the mold used at this time is manufactured. The ground 23 (see FIG. 2A) is formed by blasting using glass beads. For example, a bead blast of # 70 (JIS R6001) is used. The pressure is about 4.5 kg.
In this case as well, the maximum roughness of the pear surface of the pear surface 23 is, for example, in the range of 0.5 μm to 5 μm, and actually 2 to 3 μm is preferable.
The disk substrate 1 to be molded is as described in FIG. 3, but the pear ground 11 has a maximum roughness in the range of 0.5 μm to 5 μm and has a smooth surface as shown in FIG. A substantially spherical object collision shape.

For the disk substrate 1, a layer structure on the signal reading surface 3 side is formed in steps F202, F203, and F204 (see FIGS. 4A and 4B).
That is, in step F202, the reflective film 7 made of, for example, Ag alloy is formed on the signal reading surface 3 side where the information pit pattern is formed.
Next, in step F203, the cover layer 6 is formed by spin coating with an ultraviolet curable resin.
In step F204, the hard coat layer 8 is formed as a surface treatment on the signal readout surface 3 side. The hard coat layer 8 may not be formed.

Next, in step F205, as shown in FIG.7 (c), the moisture-proof film | membrane 10 is formed in the surface of the pear ground 11 by the side of the label printing surface 2 side. For example, the moisture-proof film 10 is formed by sputtering of SiN. The thickness of the moisture-proof film 10 needs to be 5 nm or more in order to obtain a moisture-proof effect. On the other hand, if it is too thick, the film formation time may be prolonged, and conversely, the moisture-proof effect may not be obtained. Preferably, the moisture-proof film 10 has a thickness in the range of 5 nm to 20 nm.
Note that the moisture-proof film 10 in step F205 may be formed before or during the processes in steps F202, F203, and F204.

Through the above steps, the necessary layer formation has been completed on the signal reading surface 3 side and the label printing surface 2 side, and the quality check is performed on the disk substrate 1 that has undergone the above steps in the inspection process of step F206. . In step F207, the disc substrate 1 as an acceptable product is stored in a state of being stacked on the substrate transport table 30 shown in FIG. 12, and transported to the next process.
The large number of disk substrates 1 stacked and conveyed on the substrate conveyance table 30 are then taken out one by one in the printing process of step F208 and printed on the label printing surface 2 side.
In this printing process, for example, color printing is performed on the entire surface on the label printing surface 2 side on which the matte surface 11 and the moisture-proof film 10 are formed, for example, as offset printing.
The optical disc is completed through the above steps.

In the example of FIG. 10, the moisture-proof film 10 can be validated by making the pear ground 11 (mold pear ground 23) have a substantially spherical object collision shape. Therefore, even when different materials are used for the disk substrate 1 and the cover layer 6, the generation of warpage can be remarkably reduced, and the manufacturing yield can be greatly improved in practice.
FIG. 11 shows the warp prevention effect.
In FIG. 11, the horizontal axis represents time and the vertical axis represents the amount of warp, and shows how the warp changes when humidity changes. In each case, a cover layer 6 made of an ultraviolet curable resin is formed on a polycarbonate disk substrate 1, and □ is a disk substrate 1 having a textured surface 11 based on a blasting process using alumina and no moisture-proof film 10 is formed. , ■ shows the case where the moisture-proof film 10 is formed in the disk substrate 1 having the matte surface 11 based on blasting with alumina. Further, ▲ is a case where the moisture-proof film 10 is formed on the disk substrate 1 having the matte surface 11 based on blasting with glass beads.
FIG. 11 shows that the warp prevention effect is hardly obtained even when the moisture-proof film 10 is formed when the pear ground 11 is made of alumina blast.
On the other hand, it can be seen that the moisture-proof film 10 functions and the warp is reduced by making the pear ground 11 of the disk substrate 1 into a substantially spherical object collision shape by the glass bead blasting.

  In FIG. 10, the case where the disk substrate 1 and the cover layer 6 are formed of different materials has been described. However, when the disk substrate 1 and the cover layer 6 are made of the same material, warping does not occur so much, that is, a moisture-proof film. 10 is not required, the pear ground 23 may be formed by either blasting with glass beads or blasting with alumina. However, even if the disk substrate 1 and the cover layer 6 are made of the same material, if it is preferable to form the moisture-proof film 10 for some reason, blasting with glass beads is performed to make the pear ground 11 (pear ground 23 ) May be a substantially spherical object collision shape.

  In the above example, the pear ground 11 (mold pear ground 23) is formed by blasting using glass beads. However, in order to make the moisture-proof film 10 function effectively, the pear ground 11 is a sphere. What is necessary is just to be made into an object collision shape. That is, even if it is not a glass bead, the blaster process using a substantially spherical body should just be performed.

As described above, the following effects are obtained in the present embodiment.
First, since the label printing surface 2 side of the disk substrate 1 is the matte surface 11, sticking of the disk substrates 1 during storage and transportation is prevented, and the efficiency of the manufacturing process is realized.
Further, the label printing surface 2 side of the disk substrate 1 is the matte surface 11 (the inner surface side of the upper cavity 22 of the mold is the matte surface 23), thereby improving the pit molding accuracy on the disc substrate 1, Thereby, a high quality optical disk can be manufactured.
Further, when the disk substrate 1 and the cover layer 6 are formed of different materials, the moisture-proof film 10 is formed on the pear ground 11 so that the pear ground 11 of the disk substrate 1 has a substantially spherical object collision shape. The warp of the disk substrate 1 can be reduced and the manufacturing yield can be improved.

In the embodiment, an example of an optical disk having a single-layer structure is given as the recording layer (information pit 3a layer) on the signal readout surface 3. Of course, the present invention is also suitable for a multi-layer disk having two or more recording layers. .
Further, the present invention can be applied to various discs such as a Blu-ray disc, a DVD (Digital Versatile Disc) disc, and a CD (Compact Disc) disc.

It is explanatory drawing of the process of the disc manufacturing method of embodiment of this invention. It is explanatory drawing of the metal mold | die for disk substrate manufacture of embodiment. It is explanatory drawing of the disk board | substrate of embodiment. It is explanatory drawing of the disc board | substrate which formed the layer in the signal reading surface side of embodiment. It is explanatory drawing of the disc board | substrate which printed on the label printing surface of embodiment. It is explanatory drawing of prevention of pit deviation of embodiment. It is explanatory drawing of the layered structural example of the disk of embodiment. It is explanatory drawing of the pear ground of embodiment. It is explanatory drawing of the shape of the glass bead and alumina of embodiment. It is explanatory drawing of the process of the other disc manufacturing method of embodiment. It is explanatory drawing of the warp prevention effect of embodiment. It is explanatory drawing of a board | substrate conveyance stand. It is explanatory drawing of the conventional disc board | substrate.

Explanation of symbols

  1 disk substrate, 2 label printing surface, 3 signal readout surface, 4 center hole, 5 protection ring, 6 cover layer, 7 reflective film, 8 hard coat layer, 9 printing layer, 10 moisture-proof film, 11 pear surface

Claims (7)

A method of manufacturing a disk recording medium in which one surface is a label printing surface and the other surface is an information reading surface,
A substrate generating step for generating a disc substrate having a concave-convex pattern on the information reading surface side and a satin-like surface having a maximum roughness of more than 0.5 μm and up to 5 μm on the label printing surface side;
A layer forming step of forming a layer on the information reading surface side;
A storage step of stacking and storing a plurality of disk substrates that have undergone the layer formation step,
A disk manufacturing method comprising:   In the above substrate generation process, a disk substrate is generated using a mold in which the inner surface corresponding to the label surface side of the disk substrate has a matte surface with a maximum roughness of more than 0.5 μm and up to 5 μm. The disk manufacturing method according to claim 1.   The disc manufacturing method according to claim 2, wherein the matte surface of the mold is a surface formed by colliding a substantially spherical object by blasting.   The disc manufacturing method according to claim 3, wherein in the layer forming step, a moisture-proof film is further formed on the label printing surface having a satin finish.   The matte surface of the mold is rough enough to prevent pit displacement when the resin is cooled in the mold and when the mold clamping force is released during the substrate generation process. The disk manufacturing method according to claim 3. A disk recording medium in which one side is a label printing surface and the other side is an information reading surface,
The label printing surface side is a satin-like shape with a substantially spherical collision shape within a range where the maximum roughness of the satin surface is greater than 0.5 μm and up to 5 μm, and the information reading surface side of the disc substrate having an uneven pattern , A disk recording medium formed by forming a layer on the information reading surface side.   7. The disc recording medium according to claim 6, wherein a moisture-proof film is formed on the label printing surface side of the satin-like disc substrate, and printing is performed.

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