JP2007226891A - Optical disk recording medium, disk manufacturing method and recording apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make it difficult to manufacture a pirated version of a disk by providing a recording layer by printing even in a recent high recording density disk wherein a pit surface of a substrate is provided on a laser beam incident side surface. <P>SOLUTION: The recording layer by printing is formed by forming a paint of a material having reflectivity in a prescribed pattern onto a transmissible layer formed on a surface opposite to the pit surface of the substrate or directly onto the surface opposite to the pit surface of the substrate. Thereby, it can be avoided that practical use is made difficult as the case a printing recording layer is merely conventionally provided on the rear side of a reflection film, physical transfer of copy right protection information recorded by printing is difficult and manufacture of the pirated version of the disk is made difficult. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical disk recording medium, a manufacturing method thereof, and a recording apparatus.

Japanese Patent No. 3454410 JP 2001-176132 A

  As an optical disk, in particular, a read-only ROM disk is widely used around the world as a package medium because a large number of replica substrates can be manufactured in a short time by plastic injection molding from a single stamper. For example, CDs (Compact Discs), DVDs (Digital Versatile Discs), and the like are widely used as ROM disks for recording information such as music and video.

Conventionally, so-called pirated discs have been created by illegally copying the recorded data based on ROM discs sold as package media in this way, and copyright infringement has been a problem.
In general, a pirated disc is produced by producing a stamper by producing a stamper by a mastering process based on a signal reproduced from a regular disc. Alternatively, it is created by copying a signal reproduced from a regular disc to a recordable disc.

  Various techniques have been proposed to prevent the production of pirated discs. One of them is a technology for adding different identification information for each disc, for example. In this way, by adding different identification information to each disk, it is possible to construct a system in which the playback device reads the identification information and transmits it to an external server device via a network. If such a system is used, for example, when a pirated disk is created and sold, a large amount of the same identification information is detected by the server device, so that the presence of the pirated disk can be detected. Furthermore, it may be possible to specify a pirated dealer by specifying the playback apparatus that has transmitted the detected identification information.

However, it is useful for copyright protection that identification information unique to each disc is recorded so that it cannot be easily copied by a commercially available drive device.
Therefore, for example, in Patent Document 1 described above, the identification information is recorded by forming a mark on a reflective film of a disk to give a slight change in reflectance. That is, in the disc described in Patent Document 1, main data (content data, management information, etc.) is recorded by a combination of pits and lands, and a minute reflection with respect to a reflective film on a predetermined pit or land. By forming a mark that gives a rate change, sub data (identification information) other than the main data is recorded.

  The mark recording on the reflective film is performed by laser irradiation with a recording power higher than the laser power during reproduction. At this time, the change in reflectance due to the mark is made minute so as not to affect the reproduction of the main data recorded by the combination of pits and lands. That is, this prevents the sub data from being reproduced in the normal reproduction operation for the main data.

By the way, in the above description, it is assumed that the pirated disc is created from the reproduction signal of the regular ROM disc. However, as another method, the stamper is created by directly transferring the physical shape of the substrate of the ROM disc. A method is also conceivable.
Specifically, the shape of the pits and lands formed on the substrate is exposed by peeling the disc cover layer and the reflective film from the substrate. Then, by physically transferring the concavo-convex shape thus exposed, the content recorded on the disk is duplicated.

  In the disc described in Patent Document 1, identification information for each disc is recorded by a mark formed on the reflective film. According to this, the physical transfer method that requires the cover layer and the reflective film to be peeled off from the substrate as described above cannot transfer even the mark (identification information) formed on the reflective film. Therefore, it is considered that the production of pirated discs can be prevented.

As another method for preventing the manufacture of pirated discs by physical transfer, the present applicant has previously proposed a technique as described in Patent Document 2 above.
FIG. 7 shows a cross-sectional structure of an optical disc as one embodiment of the invention described in Patent Document 2.
In the optical disc described in Patent Document 2, as shown in the figure, the pit forming surface, which is the surface opposite to the laser light incident side of the pit transfer substrate 101, is slightly transparent. After the reflective film 104 is formed, a recording layer 105 for recording sub-data is further provided on the back side (on the upper layer) when viewed from the laser light incident side. Further, a protective film 103 is formed on the upper layer.

  In this optical disc, the recording layer 105 is a layer formed by printing. Specifically, printing is performed so that a required pattern (pattern) is formed by paints having different reflectivities. By forming such patterns having different reflectivities, sub-data values are recorded in the recording layer 105.

In this case, since a material having a certain degree of transparency is selected as the reflective film 104, the laser beam is irradiated through the objective lens so as to be condensed on the reflective film 104 as shown in the figure. Then, part of the light passes through the reflective film 104 and reaches the recording layer 105. When the light reaches the recording layer 105, reflected light corresponding to the reflectance of the paint applied at the arrival position is obtained, and this is returned to the objective lens side through the reflective film 104.
At this time, since the optical disk is driven to rotate, the amount of reflected light from the recording layer 105 obtained by irradiating the laser beam as described above is very small depending on the pattern formed on the recording layer 105. It will be obtained as it changes. By detecting this slight change in the amount of reflected light, the sub-data value can be reproduced.

Note that the amount of reflected light from the recording layer 105 becomes small in this way because the reflected light obtained by irradiating the recording layer 105 with the laser light through the reflective film 104 and passing through the reflective film 104 is signaled. This is because it is used as light.
On the playback device side, each value of the sub data is validated based on the result of performing a large number of samplings and integrating them with respect to such a slight change in the amount of reflected light reflecting the value of the sub data from the recording layer 105. Can be detected.
It is effective that the amount of reflected light from the recording layer 105 is so small that the sub-data signal light affects the reproduction of the main data recorded by the pits and lands. Has been prevented.

  As shown in FIG. 7, even when the secondary data is recorded by printing, the secondary data is not recorded due to a physical shape change, thereby effectively producing a pirated disk by physical transfer. Can be prevented.

For confirmation, if it is intended to realize only that sub-data can be recorded, in the configuration of FIG. 7, the recording is performed in the order of the substrate 101 → the recording layer 105 → the reflective film 104. The layer 105 is a printed layer made of a paint having a different transmittance so that a change in transmittance as the recording layer 105 is given before entering the reflective film 104 so that reflected light reflecting the sub data can be obtained. It is also possible. However, when such a configuration is adopted, the change in the amount of light according to the recording information of the sub data becomes large, which easily affects the reproduction of the main data.
In this respect, the recording layer 105 by printing needs to be provided in the order of the substrate 101 → the reflective film 104 → the recording layer 105 as shown in FIG.

By the way, in recent years, an optical disc having a new structure different from conventional CDs and DVDs has been proposed and put into practical use in response to a demand for an increase in data storage capacity.
The methods for realizing a large capacity can be broadly divided into a method for increasing the recording layer and a method for increasing the recording density. For example, when the recording density is increased, the recording layer is formed more finely. It is necessary to secure a higher NA (Numerical Aperture) so that pits and lands can be detected at a high magnification.

Here, when a higher NA is set in this way, the working distance in the focus direction is also constrained accordingly, and accordingly, the distance from the objective lens to the pit surface is shortened as the structure on the optical disc side. It is necessary to configure as follows.
That is, according to this, when a conventional disc structure such as a CD / DVD in which the pit transfer substrate 101 shown in FIG. 7 is the laser incident side is adopted, the thickness of the pit transfer substrate 101 is further increased. It needs to be thin.

  However, the pit transfer substrate 101 is required to have a predetermined thickness or more from the viewpoint of ensuring strength, for example. That is, for this reason, as shown in FIG. 7, in the conventional disk structure in which the pit forming surface of the pit transfer substrate 101 is located on the back side as viewed from the laser incident side, there is a limit to increasing the NA, and the data that can be expanded There was also a limit in storage capacity.

Therefore, in recent years, for example, as shown in FIG. 8 below, the pit formation surface of the pit transfer substrate 101 is made to be a laser incident side surface, and the reflective film 102 → the cover layer 103 is formed on this pit formation surface. A laminated disk structure has been proposed and put into practical use.
A recording medium having such a structure is known as, for example, a Blu-ray Disc (registered trademark).

  According to the disk structure in which the pit forming surface of the pit transfer substrate 101 is positioned on the laser light incident side as described above, there is no need to interpose the thickness of the substrate body between the objective lens and the pit forming surface, The distance between them can be shorter. In other words, this makes it possible to achieve a higher NA than in the case of the conventional disk structure described above, and as a result, it is possible to achieve a higher recording density and consequently a larger storage capacity.

  Here, even for a large-capacity disc having a structure like the above-mentioned Blu-ray disc, for example, recording of sub-data as copyright protection information is difficult to manufacture a pirated disc by providing a recording layer by printing as described above. It can be considered to be.

However, as described above, the structure of a large-capacity disk such as a Blu-ray disk is different from the structure of the conventional disk as shown in FIG. 7, and the pit formation surface of the pit transfer substrate 101 is located on the laser light incident side. Has been.
Assuming that the recording layer 105 is provided on the back surface of the reflective film 104 (the back surface when viewed from the laser incident side) in the same way as in FIG. The disc cross-sectional structure in this case is as shown in FIG.

  That is, as the structure of the optical disk in that case, first, as shown in FIG. Further, after forming a reflective film 104 having transparency so as to be overcoated thereon, a cover layer 106 is then formed thereon.

However, according to the structure shown in FIG. 9, even if the recording layer 105 can be formed so as to leave the concave shape of the pits as shown in the figure, the reflection is formed so as to be overcoated thereon. The film 104 may not be able to leave a concave shape of pits.
Alternatively, it is conceivable that the pits are filled when the recording layer 105 is formed, and in this case, the concave shape of the pits is lost in the reflective film 104.
If the cross-sectional shape of the reflective film 104 does not accurately reflect the pit formation pattern in this way, it is natural that the main data recorded by the pits cannot be properly reproduced. It will be.
In particular, since an optical disk in this case is assumed to be a high recording density disk, the size of the pits is small accordingly, and it is highly possible that the pits are filled by the formation of the recording layer 105 as described above. It will be a thing. In other words, if a technology for preventing piracy based on the conventional technique shown in FIG. 7 is simply applied to a large-capacity optical disk having a structure as shown in FIG. 8, this may not be effectively put into practical use.

Accordingly, an object of the present invention is to provide an optical disk recording medium that makes it extremely difficult to manufacture a pirated disk even when the structure of a recent large-capacity disk as shown in FIG. 8 is adopted.
For this reason, in the present invention, the optical disk recording medium is configured as follows.
That is, the optical disc recording medium of the present invention includes a substrate having transparency on which pits are formed, a reflective film having transparency formed on the pit surface of the substrate on which the pits are formed, and the reflection A permeable cover layer formed on the film, and a permeable layer formed on a surface of the substrate opposite to the pit surface, or the substrate. A paint made of a reflective material is applied to the surface opposite to the pit surface so as to form a required pattern.

Further, in the present invention, a disk manufacturing method for manufacturing an optical disk recording medium on which main data is recorded by pits formed on a substrate is as follows.
That is, a master disc generating step for generating a master disc on which pits based on the main data are formed is provided.
Then, a substrate having a pit surface on which the pits are formed is generated by a stamper created based on the disc master, and a reflective film having at least transparency to the pit surface and a cover layer are formed thereon. In addition, based on sub-data different from the main data, with respect to the layer having transparency formed on the surface opposite to the pit surface on the substrate, or the pit surface on the substrate A disk generation / printing recording process is provided in which a coating made of a reflective material is applied to the opposite surface so that a required pattern is formed.

In the present invention, a transparent substrate having pits formed thereon, a transparent reflective film formed on the pit surface of the substrate having the pits formed thereon, and a reflective film formed on the reflective film. A recording apparatus for recording information on a disk-shaped medium having at least a film-coated cover layer is configured as follows.
That is, based on the sub-data different from the main data recorded by the pits on the substrate, the transparent layer formed on the surface of the substrate opposite to the pit surface, or The substrate is provided with printing means for applying a coating made of a reflective material on a surface opposite to the pit surface on the substrate so that a required pattern is formed.

According to the present invention, the sub data different from the main data recorded by the pits can be recorded by applying (that is, printing) the reflective paint.
In addition, in the present invention, the layer on which the sub-data is recorded by such printing is formed on the surface opposite to the pit surface on the substrate (that is, opposite to the laser beam incident side). It is directly formed with respect to the layer which has the permeability | transmittance made, or with respect to the surface on the opposite side to the said pit surface in the said board | substrate. That is, the recording layer is formed by printing at the layer position on the back side of the substrate as viewed from the laser beam incident side.
In this way, by providing a recording layer by printing at the layer position on the back side of the substrate when viewed from the laser beam incident side, the reflective film can be formed directly on the pit surface, and the conventional method is applied as it is Thus, it is possible to prevent the problem of impeding its practical use from occurring.
For confirmation, as described above, the recording layer by printing is formed directly on the surface opposite to the pit surface on the substrate through the layer having transparency. As a result, the laser beam incident through the substrate body can reach the recording layer by this printing. That is, this allows the reflected light obtained in response to the application of the paint to be appropriately returned as return light through the substrate, so that the signal recorded on the recording layer by printing is properly reproduced. Can be.

  Thus, in the present invention, the sub data recording layer is provided on the back side of the substrate as viewed from the laser beam incident side, so that the reflective film can be formed directly on the pit surface of the substrate. Therefore, it is possible to provide an optical disk recording medium capable of effectively preventing the production of a pirated disk so that it can be put into practical use in response to the case where a structure of a high recording density disk having a pit surface on the laser beam incident side is employed.

  Further, in the present invention, since the sub data is recorded by printing and not by physical shape change, it is very difficult to manufacture a pirated disk by physical transfer.

Further, according to the disk manufacturing method of the present invention, an optical disk recording medium having the above excellent effects can be manufactured.
Also, according to the recording apparatus of the present invention, it is possible to record the sub data for copyright protection on the layer position on the back side of the substrate as viewed from the laser beam incident side by printing.

Hereinafter, the best mode for carrying out the invention (hereinafter referred to as an embodiment) will be described.
FIG. 1 is a cross-sectional view showing a cross-sectional structure of an optical disc 10 as an optical disc recording medium of the present embodiment.
The optical disk 10 of the present embodiment is a read-only ROM disk, and specifically adopts a disk structure and format compliant with an optical disk called a Blu-Ray Disc (registered trademark). Become.

In FIG. 1, an optical disc 10 is provided with a pit transfer substrate 1 having a pit formation surface (also referred to as a pit surface) on which pits are formed by stamper transfer. The pit transfer substrate 1 is made of polycarbonate, for example.
In the pit transfer substrate 1, a concavo-convex cross-sectional shape is given on the pit surface. The concave cross section is a pit, and the convex cross section is a land. In the optical disc 10, information can be recorded by a combination of these pits and lands, specifically, the lengths of the pits and lands.

A reflective film 2 is formed on the pit surface side of the pit transfer substrate 1 as shown in the figure.
In the case of the present embodiment, the reflective film 2 is formed of a material that has both reflectivity and transparency, such as a so-called double-layer film used in a current multilayer disk.

  For confirmation, the reflectance of the reflective film 2 is determined by the reflected light (return light) when the laser light for reading the signal recorded by the pits (and lands) is irradiated. It is sufficient that the light quantity sufficient for detection is obtained, and the transmittance is recorded when a laser beam for reading a signal recorded on the recording layer 5 described later is irradiated. What is necessary is just to set so that the light quantity sufficient for the detection of the reflected light obtained from the layer 5 may be obtained.

  A cover layer 3 made of polycarbonate or the like is formed on the reflective film 2 as shown in the figure. The cover layer 3 is provided to protect the pit surface on which the reflective film 2 is formed.

Here, the reflective film 2 is laminated on the pit forming surface of the pit transfer substrate 1 to give the concave and convex sectional shape according to the shape of the pit and land as described above. Thus, when the laser beam is irradiated through the cover layer 3 so as to be condensed on the reflection film 2, the amount of the reflected light is changed according to the unevenness. As a result, on the reproducing apparatus side that reproduces the optical disc 10, information recorded by a combination of pits and lands can be detected (read out) based on the reflected light from the reflecting film 2 of the irradiated laser light. it can.
As can be understood from this description, in the optical disc 10, it can be seen that the pit formation surface of the pit transfer substrate 1 is located on the surface on the incident side of the laser beam during reproduction.

  On the surface of the pit transfer substrate 1 opposite to the pit formation surface (that is, the surface opposite to the laser light incident side), a base layer 4 is formed as shown. . Then, a paint 5a is partially applied to the base layer 4 as shown in the figure, and a shielding protective film 6 is further formed on the base layer 4 where the paint 5a is not applied and the paint 5a. The film is formed so as to cover the top.

  Here, the base layer 4 is made of a material on which the paint 5a can be applied, and laser light for reading a signal recorded by applying the paint 5a is applied to the base layer 4 as will be described later. A material having permeability is selected so that it can pass through. That is, as the base layer 4, a material that is suitable as a base for printing and has transparency is formed.

In addition, the coating 5a applied to the underlayer 4 is partially applied on the underlayer 4, whereby a required pattern of the coating 5a is printed on the underlayer 4. Will be.
In this case, a shielding protective film 6 is further formed. By this, a region where the paint 5a is applied and a part of the other shielding protective film 6 are formed on the base layer 4. Two regions, the filmed region, will be formed.

  Further, the shielding protective film 6 is provided to prevent the paint 5a from appearing on the surface of the optical disc 10 and to prevent the pattern formed by the paint 5a from being visually identified. For this reason, as the protective film 6 for shielding, a material having no permeability or a very low transmittance is formed. As the shielding protective film 6 in FIG. 1, for example, an ultraviolet curable resin can be used.

In this case, the coating material 5a is made of a reflective material, and the material is selected so that the reflectance is different from that of the protective film 6 for shielding.
As a result, in the upper layer of the base layer 4, a required pattern having a different reflectance is formed by application of the paint 5 a. As a result, when the laser beam is irradiated so as to be focused on the layer position where the paint 5a is applied, the amount of reflected light can be changed at the portion where the paint 5a is applied. In other words, with such a configuration, data (referred to as main data) other than the data (referred to as main data) recorded on the pit forming surface on the pit transfer substrate 1 depending on the formation pattern of the application portion of the paint 5a. Can be recorded).

In addition, the layer to which the reflectance change is given by applying the coating material 5a as described above is hereinafter referred to as a recording layer 5 from the viewpoint of a layer on which the sub data is recorded.
According to the above description, in this case, since the reflectance is changed by the paint 5a and a part of the shielding protective film 6, the paint 5a and a part of the shielding protective film 6 are mixed. The layer position is the recording layer 5.

Here, in the conventional CD (Compact Disc) and DVD (Digital Versatile Disc) type optical discs, as shown in FIG. 7, a pit surface is provided on the surface opposite to the laser light incident side. The pit transfer substrate 101, the reflective film 104, the recording layer 105, and the protective film 103 are stacked in this order, and the pit surface is irradiated with laser light through the thickness of the substrate 101 main body.
As a result, the recording layer 105 on which information for copyright protection as sub data was recorded could be directly provided on the upper side where the reflective film 104 was formed on the pit surface.

  On the other hand, in the optical disk 10 of the present embodiment, in order to achieve higher recording density than the conventional CD or DVD system, the pit surface of the pit transfer substrate 1 is different from the case of FIG. It is provided on the surface that becomes the side. The reflective film 2 and a cover layer 3 are further laminated on the pit surface. In other words, with such a configuration, the distance from the disk surface on the laser beam incident side to the pit formation surface can be shortened, and accordingly, a higher NA (NA = Numerical Aperture) can be accommodated. It is possible to cope with an increase in recording density and, in turn, an increase in storage capacity.

However, in the case where the pit surface of the pit transfer substrate 1 is provided on the laser light incident side in this way, recording is performed on the back surface of the reflective film (the back surface as viewed from the laser incident side) as in FIG. Assuming that a layer is provided, as shown in FIG. 9, the recording layer 105 is formed so as to be overcoated even if it can be formed so as to leave a concave shape of the pit. In the reflective film 104, there is a possibility that the concave shape of the pit cannot be left.
Alternatively, it is conceivable that the pits are filled when the recording layer 105 is formed, and in this case, the concave shape of the pits is lost in the reflective film 104.
If the cross-sectional shape of the reflective film 104 does not accurately reflect the pit formation pattern in this way, it is natural that the main data recorded by the pits cannot be properly reproduced. It will be.
In particular, since an optical disk in this case is assumed to be a high recording density disk, the size of the pits is small accordingly, and it is highly possible that the pits are filled by the formation of the recording layer 105 as described above. It will be a thing. In other words, if the anti-piracy technology based on the conventional method shown in FIG. 7 is simply applied to the large-capacity optical disk as in the present embodiment, there is a possibility that this cannot be effectively put into practical use.

Therefore, in the present embodiment, as shown in FIG. 1, the recording layer 5 is provided at a layer position on the back side of the substrate 1 when viewed from the laser beam incident side. Specifically, the layer position on the back side of the substrate 1 when viewed from the laser light incident side is provided at the next layer position through the base layer 4.
As a result, simply applying the configuration of FIG. 7 as it is, the cross-sectional shape of the reflective film is the pit surface as in the case where the recording layer is provided directly on the back surface of the reflective film as seen from the laser light incident side. The sub-data for copyright protection can be recorded while avoiding the situation where the uneven shape is not reflected. That is, sub-data for copyright protection can be recorded so that it can be put into practical use.

  For confirmation, the sub data is recorded on the recording layer 5 in this case by printing, and is not recorded by a physical shape change. This makes it very difficult to manufacture pirated discs by physical transfer.

  By the way, in the configuration of the conventional optical disc as shown in FIG. 7, since the recording layer 105 by printing is directly formed on the back side of the reflective film 104 when viewed from the laser light incident side, the laser light is reflected on the reflective film 104. Under the focus, a part of the light can pass through the reflective film 104 and reach the recording layer 105, and light reflected by the coating material of the recording layer 105 can be returned through the reflective film 104. I was able to. That is, according to such a conventional configuration, the main data and the sub data can be read using the common laser beam by focusing on the reflective film 104.

  However, in the optical disk 10 of the present embodiment shown in FIG. 1, the recording layer 5 is provided on the back side of the substrate 1 when viewed from the laser light incident side. In order to read the signal recorded on the recording layer 5 formed on the back surface of the pit transfer substrate 1 in this way, it is necessary to focus the laser beam on the recording layer 5 through the thickness of the substrate 1 body.

According to the above description, the laser beam with high NA for reading the signal of the pit surface of the substrate 1 cannot be focused through the thickness of the substrate 1 main body. That is, the focus cannot be adjusted to the recording layer 5. If the recording layer 5 is not focused in this way, the laser light is scattered before reaching the recording layer 5, and the reflected light from the coating 5 a on the recording layer 5 is hardly obtained. That is, it becomes extremely difficult to detect the reflected light according to the sub data.
For this reason, in reading the signal recorded on the recording layer 5 in the optical disc 10 of the present embodiment, the laser beam for reproducing the main data cannot be used in common.

Therefore, when reading the sub data recorded on the recording layer 5 of the optical disc 10 of the present embodiment, a separate laser beam is irradiated as shown in the sectional view of FIG.
Specifically, the reading is performed by irradiating a laser beam by a conventional CD or DVD-based NA capable of securing a working distance that can be focused through the thickness of the substrate 1 main body.

Specifically, since the optical disc 10 in this case is assumed to be compliant with the Blu-ray disc as described above, the reproduction of the main data, that is, the laser light applied to the reflective film 2 is as follows. The same blue laser light (wavelength λ = 405 nm, NA = 0.85) as that used in the current Blu-ray disc is used.
For reading out the sub data recorded on the recording layer 5, for example, when the recording layer 5 is provided at the same layer position as the DVD system with a substrate thickness of 0.6 mm, the red laser beam (wavelength λ = 650 nm, NA = 0.65), and a CD-type red laser (wavelength λ = 780 nm, NA = 0.45) is used when the substrate thickness is 1.2 mm as in the case of the CD system. It may be used.
That is, it is possible to secure a working distance in which the laser beam can be focused according to the layer position of the recording layer 5, and to the recording layer 5 using a laser beam having a lower NA than that for reading main data. It is only necessary to read out the sub data to be recorded.

Next, FIG. 3 is a diagram for explaining a manufacturing process (manufacturing method) of the optical disc 10.
In FIG. 3, when the optical disc 10 is manufactured, first, the formatting step S11 in the drawing is executed. This formatting step S11 is performed using, for example, a computer.
In this formatting step S11, a conversion operation is performed on content data (user data) to be recorded on the optical disc 10 so as to obtain a format data string according to a predetermined standard. That is, in the case of the embodiment, the conversion operation is performed so that a data string according to the Blu-ray Disc standard is obtained. In practice, address information insertion processing, addition of error detection codes and error correction codes to user data, interleaving processing, and the like are also performed.

In the variable length modulation step S12, variable length modulation processing is performed on the data string generated in the formatting step S11. In the case of the embodiment, RLL (1, 7) PP (Parity preserve / prohibit, RLL: Run Length Limited) modulation processing and NRZI (Non Return to Zero Inverse) modulation processing are performed. The “0” “1” pattern of the data string obtained by the variable length modulation step S12 becomes a pattern of pits and lands actually formed on the optical disc 10.
Data obtained by formatting user variable data and performing variable-length modulation processing in this way is referred to as main data here.

Subsequently, the master generation step S13 is performed. The master production step S13 is performed using a mastering device.
In the master production step S13, first, a photoresist is applied to the glass master. Then, by irradiating the laser beam according to the main data generated in the variable length modulation step S12 in a state where the glass master coated with the photoresist is rotationally driven in this manner, a pattern of unevenness along the recording track Form. In other words, pits and lands are formed.
Next, the resist on which the pits and lands are formed is developed and fixed on the glass master, and the surface of the master is electroplated to generate the metal master D1 shown in the figure.

Each process for actually generating the optical disc 10 is performed using the metal master D1 thus generated.
First, the illustrated transfer / film formation step S14 is performed.
In this transfer / film formation step S14, a stamper is first created based on the metal master D1. And this stamper is arrange | positioned in a shaping | molding die, and the pit transcription | transfer board | substrate 1 is produced | generated with transparent resins, such as a polycarbonate and an acryl, using an injection molding machine. On the pit transfer substrate 1, pit and land patterns corresponding to the main data generated in the previous modulation step S12 are formed along the recording track.
A reflective film 2 is formed on the pit forming surface of the pit transfer substrate 1 by vapor deposition or the like, and a cover layer 3 made of, for example, an ultraviolet curable resin is formed on the reflective film 2.

In the transfer / film formation step S14 in this case, the underlayer 4 is further formed on the surface of the pit transfer substrate 1 opposite to the pit surface.
In this way, a disc in which the reflective film 2 and the cover layer 3 are laminated on the pit formation surface side of the pit transfer substrate 1 and the base layer 4 is laminated on the opposite side of the pit transfer substrate 1 from the pit formation surface. Is a disk on which only main data is recorded, and is hereinafter referred to as a main data recording disk D2.

Subsequently, the sub data recording step S15 is executed.
Here, in the embodiment, sub data is recorded in addition to the main data recorded by the pit and land pattern as described above.
In this case, the sub data records serial number information that is unique to each optical disc 10 (main data recording disc D2) as actual data that is the data content portion. That is, as a result, each optical disc 10 generated through the sub-data recording step S15 is given unique identification information (identification number).
Further, in addition to the identification information as the actual data, in this case, an error correction code is also added as the sub data. By attaching this error correction code, it becomes possible to perform an error correction process on the identification information during reproduction.

In this case, the sub data is recorded so as to overlap with a specific address section of the main data by pits and lands, for example.
That is, in this case, an area in which sub-data is to be written is determined in advance with the playback device side, and the playback device side determines the predetermined area based on the result of detecting address information obtained by playing back the main data. After accessing the area, the recording layer 5 is irradiated with laser light to reproduce the sub data.

The sub data recording step S15 shown in FIG. 3 is performed using the sub data recording apparatus 20 having the configuration shown in FIG.
In FIG. 4, the sub data recording device 20 may be considered to have substantially the same basic configuration as, for example, a general printer device that is widely spread at present.
First, a CPU (Central Processing Unit) 21 performs overall control and arithmetic processing of the sub data recording device 20 based on the activated program.
The CPU 21 includes a ROM (Read Only Memory) 22 and a RAM (Random Access Memory) 23 as shown in the figure.
The ROM 22 stores an operation program for the CPU 21, a program loader, various arithmetic coefficients, parameters used in the program, and the like.
Further, in the RAM 23, a data area and a task area for the CPU 21 to execute the program are temporarily secured.

  In particular, the ROM 22 in this case stores an ID / image conversion program 24 shown in the figure for converting identification information (ID information) as sub-data into required image data (image data).

  Here, as described above, the sub-data is recorded in a predetermined area on the disc predetermined with the reproducing apparatus side. The ID / image conversion program 24 is an image for printing a pattern corresponding to the value of identification information (in this case, the value of sub-data including an error correction code in this case) for this predetermined area. This is a program for generating data (print data).

For example, according to the processing of the CPU 21 in accordance with the ID / image conversion program 24 as an example, as shown in FIG. 5, the image data on the surface of the optical disk 10 is assumed to be stored in a predetermined area on the surface. Image data in which a pattern as data is formed is generated.
That is, if a write area (write start address to write end address) is determined in advance, the physical position on the disk can be specified based on the address information. Then, image data for the disk surface is generated so that a pattern (print pattern) corresponding to the value of the sub data is formed at the specified physical position.

  Returning to FIG. 4, an image memory 25 is provided for the CPU 21. The image memory 25 is used for storing image data as shown in FIG. 5 generated by the CPU 21 in accordance with the ID / image conversion program 24 as print data.

  The operation input unit 26 is an input device such as an operation key (not shown) provided so as to be exposed on the outer surface of the case of the sub data recording device 20, for example, and the user performs various operation inputs and data inputs. Information input by the operation input unit 26 is transmitted to the CPU 21 as operation or data input information. The CPU 21 performs necessary calculations and controls corresponding to the input information.

  Here, it is assumed that the value of the identification information constituting the sub data is input to the CPU 21 by a user operation input via the operation input unit 26. Based on the input identification information, the CPU 21 performs necessary processing such as addition of the error correction code described above to generate sub data.

  The timing control unit 27, the discharge control unit 28, the paint tank 29, the discharge head 30, the head feed control unit 31, the head feed motor 32, the slide control unit 33, and the slide motor 34 are arranged on the stage 35 as illustrated. The main data recording disk D2 is actually configured to perform printing based on the above-described image data.

  First, the timing control unit 27 outputs various timing control signals for controlling each operation timing of the ejection head 30, the head feed motor 32, and the slide motor 34 based on the image data supplied from the CPU 21, respectively. 28, supplied to the head feed control unit 31 and the slide control unit 33.

The ejection control unit 28 controls the ejection operation by the ejection head 30 based on the timing control signal from the timing control unit 27.
The discharge head 30 is provided with a paint tank 29 as shown, and the paint supplied from the paint tank 29 is discharged under the control of the discharge control unit 28.
In the case of the present embodiment, since the paint 5a is applied to the base layer 4 of the main data recording disk D2, the paint tank 29 is filled with the paint 5a.

Although not shown in the figure, in this case, the ejection head 30 is capable of reciprocatingly sliding the ejection head 30 on a main data recording disk D2 disposed on the stage 35 in a predetermined axial direction. It is held by a holding reciprocating slide mechanism.
The reciprocating slide operation of the discharge head 30 by the reciprocating slide mechanism is realized by driving the head feed motor 32 shown in the figure.

  The operation of the head feed motor 32 is performed based on a drive signal from the head feed control unit 31. The head feed control unit 31 controls the operation of the head feed motor 32 by generating a drive signal based on the timing control signal from the timing control unit 27 and supplying the drive signal to the head feed motor 32. To be done.

The stage 35 is configured such that the main data recording disk D2 can be arranged, and a slide mechanism (not shown) that slides the arranged main data recording disk D2 in a direction perpendicular to the reciprocating sliding direction of the ejection head 30. ).
The slide motor 34 slides the main data recording disk D2 disposed on the stage 35 in a direction perpendicular to the feeding direction of the ejection head 30 by driving the slide mechanism of the stage 35.

  The operation of the slide motor 34 is controlled by a slide control unit 33. The slide control unit 33 generates a drive signal for driving and controlling the slide motor 34 based on the timing control signal from the timing control unit 27 described above. The operation of the slide motor 34 is controlled by supplying this drive signal to the slide motor 34.

  With such a configuration of the sub data recording device 20, the paint 21 a filled in the paint tank 29 based on the image data generated by the CPU 21 according to the ID / image conversion program 24 based on the sub data value is transferred to the main data recording disk. It can apply | coat with respect to the base layer 4 of D2. That is, the pattern of the paint 5a as the sub data can be recorded by printing on a predetermined area on the disk predetermined with the reproducing apparatus.

  In the above description, the identification number information has been described as being manually input by the user. However, for example, a counter that increments the count value every time printing is performed on the main data recording disk D2 in the sub data recording device 20 is performed. It is also possible to configure such that the CPU 21 automatically acquires the value of the counter as identification number information.

Returning to FIG.
By the sub data recording step S15, a disk (referred to as a printed disk D3) in which the paint 5a is printed and recorded in a predetermined pattern on the base layer 4 of the main data recording disk D2 is generated.
Then, when the printed disc D3 is generated by the sub data recording step S15 as described above, a protective film forming step S16 is performed as shown in the figure. That is, the shielding protective film 6 is formed so as to cover both the paint 5a and the portion of the base layer 4 where the paint 5a is not applied.
As a result, the optical disc 10 according to the present embodiment shown in FIG. 1 is generated.

Here, with respect to the optical disc 10 of the present embodiment described as it is, the reproduction of the sub data recorded on the recording layer 5 by printing is performed while reproducing the main data.
That is, since the sub data in this case is recorded in a predetermined area on the disc as described above, the main data is first reproduced to detect the address information. It will be necessary. Then, when the predetermined area is reached based on the detected address information, the recording layer 5 is irradiated with a laser beam for reproducing the sub data as shown in FIG. Reading is started. Even during the reading, the detection of the address information based on the main data is continued, the end point of the predetermined area is waited, and the reading of the sub data is ended when the end point is reached.

Thus, when reading the sub data, it is necessary to simultaneously reproduce the main data.
According to this, as the laser light for sub data reproduction, if the change in the amount of reflected light is large, the main data may not be reproduced properly. That is, as a result, the sub data cannot be properly reproduced.

  Therefore, in the optical disc 10, the difference in reflectance between the paint 5a formed on the recording layer 5 and the shielding protective film 6, that is, the reflected light when the recording layer 5 is irradiated with laser light for reproducing sub-data. The light amount change amount is set so as to be so weak that it cannot be binarized by the binarization process for the main data. As a result, even when the reproduction of the main data is performed in parallel, the binarization can be prevented from being affected, that is, the binarization can be appropriately performed.

  As a result of the fact that the difference in reflectance between the paint 5a formed on the recording layer 5 and the protective film 6 for shielding is made weak as described above, the sub-data detection system is used for sub-data reproduction. For the RF signal obtained based on the return light of the laser beam, the sum or difference between the signal value obtained at the coating portion of the coating 5a and the signal value obtained at the portion where the shielding protective film 6 is formed is integrated. Based on this, the value is detected.

  Here, as a specific sub data value recording / reproducing method, first, as a value recording method, a section for recording each value constituting sub data is allocated. In this single value section, it is further divided into a first half section and a second half section. For example, the paint 5a is applied in the first half section, and the paint 5a is not applied in the second half section (that is, the shielding protective film 6 is formed in the second half section). The value is defined as “1”. On the contrary, if the paint 5a is not applied in the first half section and the paint 5a is applied in the second half section, the value is defined as “0”, for example.

However, in this case, since the reflectance change between the application portion of the paint 5a and the portion where the paint 5a is not applied (the formation portion of the shielding protective film 6) is made weak as described above, It is very difficult to accurately detect the value based only on the RF signal for one interval of the one value.
For this reason, in the area where the sub data is recorded, the one-value section as each value constituting the sub data is repeatedly recorded a predetermined number of times. That is, the same value is repeatedly recorded a predetermined number of times in the sub data recording area.

  According to such a recording method, at the time of reproduction of the value of the sub data, the RF signal of the first half portion is recorded for each of the one value sections recorded a plurality of times for each value of the sub data as described above. The sum or difference between the value and the value of the RF signal in the latter half section is obtained, and the value is detected based on the result of integrating the sum or difference. Then, the sub data is reproduced by performing such a detection operation for each value constituting the sub data.

When sub data is recorded, the values of the sub data can be repeatedly recorded in the same order, but in actuality, each value is set so that it is difficult to specify the value of the sub data to be recorded. It is also possible to perform recording so that the above-described single value sections to be recorded are randomly arranged in the sub data recording area.
That is, at the time of recording, each value is set in such a manner that each of the above-described one-value sections is randomly scattered in the sub-data recording area based on a predetermined algorithm determined in advance with the reproducing apparatus. Make a record.
Then, the playback device side randomly reads out each of the one-value sections in the order based on the predetermined algorithm, and integrates the sum or difference of the RF signal values in the one-value sections. A value is detected based on the result. That is, by reading data in units of one-value sections in the order based on the same algorithm previously determined with the recording side in this way, sub data recorded in a random order at the time of recording in a regular playback device Each value of can be detected appropriately.

It should be noted that the sub-data recorded on the optical disc 10 can be properly reproduced by using the regular reproduction device as described above. According to this, for example, an illegal trader used the regular reproduction device. In this case, the sub data value itself can be obtained.
However, if a pirated disc is manufactured for the optical disc 10 of the present embodiment, as is understood from the recording / reproducing method described above, the recording location (that is, the area on the disc) is not known. Don't be. In other words, even if the sub-data value itself can be reproduced, it cannot be reproduced properly unless it is recorded in an appropriate place on the pirated disc.

In the optical disk 10 of the present embodiment, the sub data is recorded by printing on the recording layer 5 as described above, and a shielding protective film 6 is formed on the recording layer 5.
Since the shielding protective film 5 is formed, it is possible to make it extremely difficult to specify the sub-data recording area by visual inspection from the outside of the optical disk 10. That is, this makes it very difficult to specify the sub data recording area and the recording pattern.
In order to specify the sub-data recording area, the protective film 6 for shielding may be peeled off to expose the paint 5a. However, since the paint 5a is recorded by printing, only the protective film 6 for shielding is used. It can be made extremely difficult to peel off, and as a result, it is possible to strongly prevent peeling of the shielding protective film 6 without impairing the coating pattern of the paint 5a.
In these respects, the optical disk 10 of the present embodiment is intended to prevent the production of pirated disks.

Subsequently, the cross-sectional views of FIGS. 6A and 6B respectively show the configurations of modified examples of the optical disk recording medium of the present embodiment. In FIG. 6, parts that are the same as those already described with reference to FIG.
First, in the modified example of FIG. 6A, the recording layer 5 is the one that reflects the change in reflectance between the paint 5a and a part of the protective protective film 6 in the case of FIG. The reflectance is changed by applying two kinds of paints (paint 5a-1 and paint 5b-1) having different rates.
Here, as shown in the figure, one paint 5a-1 is a red paint, and the other paint 5a-2 is a case where a blue paint is applied.

The red and blue paints are selected in this way, as described above, as the laser light applied to the recording layer 5 for reproducing the sub data, through the thickness of the substrate 1. This corresponds to either laser light (wavelength λ = 780 nm) used in the CD system or laser light (wavelength λ = 650 nm) used in the DVD system because of the irradiation relationship.
Generally, with respect to laser light irradiation in a long wavelength region (for example, about 600 nm to 780 nm) in the visible light wavelength region, red has a high reflectance and blue has a low reflectance. Further, for laser light irradiation in a low wavelength region (for example, about 400 nm to 500 nm), blue has a high reflectance and red has a low reflectance.
Based on this fact, it can be understood that the reflectance can be changed by applying the red and blue paints to the laser light used in the CD system and the DVD system.

  For confirmation, as shown in FIG. 6A, even when two kinds of paints are applied to change the reflectance, the paints are applied so that a required pattern is formed. There is no change in doing.

In the modification shown in FIG. 6B, the base layer 4 is omitted, and the paint 5a is directly applied to the back surface of the pit transfer substrate 1.
In this figure, as shown in FIG. 6A, the case where the reflectance is changed by two kinds of paints 5a as the recording layer 5 is illustrated. However, as shown in FIG. 1, the paint 5a and the shielding protection are shown. Similarly, when the reflectance is changed by a part of the film 6, the base layer 4 can be similarly omitted.

For confirmation, in the case of adopting the configuration of the modified example of FIG. 6B, printing is performed directly on the back surface of the substrate 1 by the paint 5a, so that the case of FIG. Compared with the case where printing is performed on the base layer 4 suitable for printing, the materials that can be selected as the paint 5a are limited.
However, if the coating material 5a is directly printed on the substrate 1 in this way, there is an advantage that the step of forming the base layer 4 can be omitted in manufacturing the optical disk recording medium.

Here, in the configuration of the optical disk recording medium described so far, the protective film 6 for shielding is directly formed on the recording layer 5, and the film for protecting and shielding the coating material 5a printed on the recording layer 5 is formed. However, it is also possible to divide the protective film for protecting the paint 5a and the shielding film into separate films.
Although not shown in the figure, in that case, as a film for protecting the paint 5a, for example, a film made of an ultraviolet curable resin or the like is formed directly on the recording layer 5, and further as a shielding film thereon. For example, a paint having no permeability or a very low transmittance may be applied.

Although the embodiments of the present invention have been described above, the present invention should not be limited to the embodiments described so far.
For example, in the embodiment, the case where the optical disc 10 is a disc compliant with the Blu-ray disc is exemplified. However, the optical disc recording medium of the present invention includes a transparent substrate on which pits are formed, and the pits on the substrate. An optical disc recording medium comprising at least a reflective film having transparency formed on the surface on which the film is formed and a cover layer having transparency formed on the reflective film, that is, a laser incident side of the substrate If this is an optical disc recording medium configured to have a pit forming surface on the surface, this can be widely applied.

In the embodiment, the case where the print recording layer formed by applying the paint 5a is formed on the base layer having transparency formed on the substrate is illustrated. Another layer can be interposed between the layers as long as they are permeable.
In any case, the print recording layer in this case is a required layer (a plurality of layers are acceptable) having transparency formed on the substrate, or the side opposite to the pit surface on the substrate. It is sufficient that the laser beam that is formed directly on the surface of the substrate and incident through the substrate can reach the print recording layer.
As a result, the reflected light obtained in accordance with the paint pattern in the recording layer can be appropriately returned as return light through the substrate, and reproduction of the signal recorded in the recording layer is performed properly. be able to.

  In the embodiment, only the case where the shielding film is directly formed on the recording layer by printing is illustrated. However, as the shielding film, at least a predetermined layer above the layer position of the printing recording layer is used. It suffices if the film is formed at the layer position. This makes it difficult to visually identify the print pattern of the paint 5a formed on the print recording layer from the outside.

It is the figure which showed the cross-section of the optical disk recording medium as embodiment of this invention. It is sectional drawing for demonstrating the read-out method about the optical disk recording medium of embodiment. It is a figure for demonstrating the manufacturing method of the optical disk recording medium of embodiment. It is a block diagram shown about the structure of the recording device of embodiment. It is a figure for demonstrating an example of the image data (print data) assumed on the board surface of an optical disk recording medium. It is the figure which showed the cross-section of the optical disk recording medium as a modification of embodiment. It is the figure which showed the cross-sectional structure of the conventional optical disk recording medium in which a recording layer is formed by printing in order to prevent pirated disk manufacture. It is sectional drawing shown about the structure of the optical disk recording medium suitable for high recording density increase. FIG. 9 is a cross-sectional view showing the structure of an optical disk recording medium when the pirated disk manufacturing prevention technology of FIG. 7 is applied as it is to the optical disk recording medium having the structure shown in FIG.

Explanation of symbols

  1 Pit transfer substrate, 2 reflective film, 3 cover layer, 4 underlayer, 5 recording layer, 5a paint, 6 shielding protective film, 10 optical disk, D1 metal master, D2 main data recording disk, D3 printed disk, 20 sub Data recording device, 21 CPU, 22 ROM, 23 RAM, 24 ID / image conversion program, 25 image memory, 26 operation input unit, 27 timing control unit, 28 discharge control unit, 29 paint tank, 30 discharge head, 31 head feed Control unit, 32 head feed motor, 33 slide control unit, 34 slide motor, 35 stage

Claims (6)

A transparent substrate with pits formed thereon;
A reflective film having transparency formed on the pit surface on which the pits of the substrate are formed;
A transparent cover layer formed on the reflective film, and
Depending on the material having reflectivity for the layer having transparency formed on the surface opposite to the pit surface in the substrate or the surface opposite to the pit surface in the substrate The paint is applied to form the required pattern,
An optical disc recording medium characterized by the above.   2. The optical disk recording medium according to claim 1, wherein a shielding film is formed at a predetermined layer position above the layer position to which the paint is applied.   2. The optical disk recording medium according to claim 1, wherein the paint is directly applied to a surface of the substrate opposite to the pit surface.   2. The optical disk recording medium according to claim 1, wherein the paint is applied to a base layer having transparency formed on a surface of the substrate opposite to the pit surface. . As a disk manufacturing method for manufacturing an optical disk recording medium in which main data is recorded by pits formed on a substrate,
A master production process for producing a master disk on which pits are formed based on the main data;
A substrate having a pit surface on which the pits are formed is generated by a stamper created on the basis of the disc master, and a reflective film having at least transparency to the pit surface and a cover layer are formed thereon. , Based on sub-data different from the main data, with respect to a layer having transparency formed on the surface opposite to the pit surface on the substrate, or on the opposite side to the pit surface on the substrate A disc generation / printing recording process for applying a coating made of a reflective material to the surface in such a way that a required pattern is formed;
A disc manufacturing method comprising: A transparent substrate having pits formed thereon, a reflective film having transparency formed on the pit surface of the substrate having the pits formed thereon, and a transparent film formed on the reflective film. As a recording device for recording information on a disc-shaped medium having at least a cover layer having
Based on sub-data different from the main data recorded by the pits on the substrate, the transparent layer formed on the surface of the substrate opposite to the pit surface, or the substrate A printing means for applying a coating made of a reflective material to a surface opposite to the pit surface in such a manner that a required pattern is formed;
A recording apparatus.

Images