JP2001028130A - Optical recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare various kinds of ciphers for preventing the content information of an optical disk from being reproduced by an existent reproducing system by providing an area composed of a pit destroying all or a part of a rugged pit stream and a pit in non-destroyed rugged shape at a prescribed position while using laser beams so as not to reproduce recording information. SOLUTION: Information to be recorded is recorded on an optical disk 1 while being enciphered by the pit in rugged shape, and managing information 2 of this recorded information is recorded on a label side. The managing information 2 is determined corresponding to a deciphering method and key information for deciphering the information can be prescribed. In order to make this key information different one by one, a pit is formed by laser light corresponding to the key information or plural kinds of key information are prepared and a pit is formed corresponding to these pieces of information. After the optical disk is molded, the shape of pits except for the key information to be used is destroyed for preventing the reproduction of information recorded in that rugged shape.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording medium in which minute irregularities corresponding to information are formed and information is read out by detecting a change in the irregularities using a laser beam. And an optical recording medium suitable for security.

[0002]

2. Description of the Related Art Conventionally, an optical recording medium on which information is read out by forming minute irregularities corresponding to information on a light-transmitting substrate and detecting a change in the irregularities using a laser beam is known. is there. For example, optical disks are generally widely used because such optical recording media can be mass-produced at low cost. Since this optical disk has a large recording capacity, it has recently been used as a recording medium for recording document information, image data, program software and the like, such as a CD-ROM, and has been widely used taking advantage of the above advantages. . By the way, when document information, image data, program software, and the like are recorded on the optical disc in this way, it is difficult for the user to check the contents and purchase the content. For example, in the case of general printed matter, it is possible to see the contents of a book arranged in a store or read the headline to check the contents, but it is possible to check the contents of the document data and image data recorded on the optical disk. If the same thing is to be performed, it is necessary to prepare a large number of optical disk reproducing devices and display devices for displaying the contents, which is not practical in terms of cost and space. Further, since a plurality of persons handle the optical disk, the optical disk may be damaged or the like, making it impossible to reproduce the data. This is extremely problematic in terms of product management.

Therefore, in recent years, information such as document data, image data, and program software has been encrypted so that it cannot be reproduced by an ordinary reproducing apparatus, and the contents of the recorded information can be confirmed in addition to the encrypted information. As described above, there is an optical disc on which information that can be reproduced by a general reproducing apparatus is recorded. The encrypted information can be reproduced if there is specific key information, and the optical disk is manufactured by narrowing down the encryption method and key information for decrypting the key to a specific number. It should be almost impossible to unravel. In this way, the optical disk itself can be distributed at very low cost or free of charge. Then, if there is any information that the user likes among the recorded information, the key information for decrypting the favorite information is provided from the selling source for a fee. By doing so, the user can check the contents and purchase only the information that he / she likes, and the problem of the store, such as cost and space, does not occur.

[0004]

By the way, the above-mentioned optical disk is manufactured using a stamper in which irregularities are formed in advance, and is manufactured using the same stamper in order to prevent encryption from being broken. A small-volume molding technique of limiting the number of optical disks to about several hundred is adopted. However, such a method loses the merit of the optical disc that the cost can be reduced by mass production. Conversely, if a large number of optical disks are manufactured from the same stamper in order to reduce the manufacturing cost, the possibility that the encryption will be broken increases.

[0005] In such an optical disk, a magnetic layer is provided on the side opposite to the surface from which light is read, and the information in the magnetic layer is encrypted or cannot be scanned by an optical head of a general reproducing apparatus. An optical disc has also been proposed in which a barcode is recorded on a label surface or an outer peripheral end, and the barcode is used as encryption. Although these optical discs have the advantage of being mass-produced, they require the provision of a second detection means other than the information reading optical head on the reproducing apparatus side, and have the disadvantage that they cannot be reproduced by existing reproducing apparatuses.

Therefore, the present invention has been made in view of the above points, and various types of encryption can be prepared so as to make it impossible to reproduce the contents information of an optical disk by a normal reproduction method. It is an object of the present invention to provide an inexpensive optical recording medium that can be mass-produced by a stamper.

[0007]

In order to make specific information such as key information (decryption information) for decrypting encrypted information different in a small number of units and to manufacture an optical recording medium at low cost, The specific information is recorded on the substrate in a manufacturing process after the substrate is injection-molded by the stamper.
Therefore, the invention for achieving the above object has a `` reflecting layer made of at least a light-reflective substance on a light-transmitting substrate on which a pit array having an uneven shape according to information is formed over a plurality of tracks, In the optical recording medium in which the information is read out by detecting the uneven shape of the pit row by a laser beam irradiated from the opposite side of the light transmissive substrate on which the pit row is formed, A pit in which the whole or a part of the uneven pit row is destroyed using a laser beam so that information cannot be reproduced,
The area consisting of pits whose irregularities are not destroyed,
An optical recording medium provided at a predetermined position. ”.

Further, in the optical recording medium according to the present invention,
It is intended to provide an "optical recording medium characterized in that information on the existence of the destroyed pits is recorded in a lead-in area."

[0009]

An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a diagram showing the appearance of an optical disk according to an embodiment of the present invention, and shows the optical disk viewed from a label surface (surface opposite to a signal reading surface). The information recorded on the optical disc 1 shown in FIG. 1 by pits having an uneven shape is recorded, for example, in an encrypted form so that it cannot be decrypted by a normal reproducing apparatus. The recorded information is recorded on the label surface. Information 2 is recorded. The management information 2 is determined according to a decoding method for decoding information recorded on the optical disc 1, and key information (decoding information) for decoding information is specified by the management information 2. You can. That is, the optical disc 1 cannot decode recorded information without key information. This key information is recorded in a key information recording area provided in a predetermined area in the optical disc 1.

In order to make the key information of the optical disc 1 different for each disc, in this embodiment, the key information is recorded in a manufacturing process after injection molding of the substrate of the optical disc. Specifically, pits corresponding to key information are formed by laser light, or a plurality of key information is prepared in advance, pits are formed according to the key information, and pits other than the key information to be used are formed. The uneven shape is destroyed after molding the optical disk so that the information recorded by the uneven shape cannot be reproduced. Hereinafter, embodiments of these optical disks will be described.

FIG. 2 is a diagram showing a cross-sectional view in the track direction of the key information recording area of the optical disc according to the first embodiment of the present invention. The lower part of the figure shows the pit shape when viewed from the signal reading surface (substrate side). The optical disk 11 shown in FIG. 1 is configured such that a reflective layer 13 made of a light-reflective material and a protective film 14 are laminated in this order on a substrate 12 on which pits 15 and 16 having irregularities according to information are formed. I have.

Among the pits 15 and 16 formed in the key information recording area shown in FIG. 1, a pit 15 is formed by injection molding using a stamper, and has a rim at the periphery of the uneven shape. Not. The pit 16
The pits are formed by cutting with a laser beam in a manufacturing process after the injection molding of the substrate 12, and have a shape having a rim 17 on the periphery of the uneven shape. This substrate 12
As the material, a material whose shape is changed by irradiation with strong laser light is used, and for example, a light-transmissive resin such as polycarbonate used for a CD is used. The reflective layer 13 is made of a metal or an alloy having a high light reflectance such as aluminum, gold, or copper, and the metal or alloy layer is composed of one layer. The protective film 14 is made of an ultraviolet curable resin.

FIG. 3 is a diagram showing a cross-sectional view in the track direction of a key information recording area of an optical disc according to a second embodiment of the present invention. As in FIG. 2, the shape of the pit when viewed from the signal reading surface (substrate side) is shown on the lower side. The same parts as those of the optical disk 11 are denoted by the same reference numerals. The optical disk 21 shown in FIG. 3 breaks the pits and projections of the pits 15 formed by injection molding with a stamper so that the information recorded by the pits and projections cannot be reproduced. I make them different. This optical disk 21 is configured such that a reflective layer 13 made of a light-reflective material and a protective film 14 are laminated in this order on a substrate 22 on which pits 15 are formed, similarly to the optical disk 11 described above.

The pits 15 recorded in the key information recording area shown in FIG. 1 are formed when the substrate 22 is injection-molded by a stamper, and some of the pits 15 are formed by laser light. Irradiation has destroyed the original uneven shape. The deformed portion 23 destroyed by the laser beam has a rim 24 on an outer peripheral portion, and an inner portion surrounded by the rim 24 is wrinkled. The generation of the wrinkles is caused by the difference between the expansion rate when the substrate 22 is deformed by the irradiation of the laser beam and the expansion rate of the reflective layer 13. Therefore, if such a recording operation is performed using laser light on the substrate 22 having no reflective layer 13, it is possible to form the deformed portion 23 without wrinkles. Note that, in FIG. 2, all the irregularities of the pits 15 formed on the substrate 22 are destroyed, but if the information by the pits 15 cannot be reproduced, only a part of the pits 15 may be destroyed. In addition, as shown in the figure, it is possible to break not only two pits but also a plurality of pits in the track direction.

As described above, the optical disks 11, 21
Is made of a material generally used in a conventional optical disk, and has almost the same structure.

Next, a method for producing the optical disks 11 and 21 will be described. The optical disks 11 and 21
Except for recording key information, it is created almost in the same manner as a conventional CD (compact disc). That is, a photosensitive film such as a photoresist is formed on the surface of the glass master disk, and the photosensitive film is irradiated with a laser beam to perform exposure and development to form pits. Here, in the case of the above-mentioned optical disk 11, exposure is not performed on a portion to be a key information recording area, and no pit or pit row is formed. In the case of the optical disk 21, a plurality of different pieces of key information are recorded in the key information recording area. The position where the key information recording area is provided is arbitrary, such as a lead-in area or the start position (header or the like) of the program software. The position is recorded in an area or the like.

Next, after forming a conductive film on the photosensitive film on which the pits are formed, a stamper is formed by plating.
The stamper is mounted on an injection molding machine, and the substrate 12 or the substrate 22 is formed from a resin such as polycarbonate. Then, a reflective layer 13 made of the above metal or alloy is vapor-deposited on the substrates 12 and 22, and an ultraviolet curable resin or the like is formed on the reflective layer 13 by spin coating.

Next, recording of key information on the optical disks 11 and 21 will be described. Recording (destruction) of key information
This is performed using a recording device dedicated to recording. The key information is recorded in the manufacturing process after the injection molding of the substrates 12 and 22 before forming the reflective layer 13 or after forming the reflective layer 13 and before forming the protective film 14, May be performed in any of the steps, such as after the formation of.

First, the case of the optical disk 11 will be described. FIG. 4 shows the state of the pits in the key information recording area of the optical disk 11 created as described above before the key information is recorded. As shown in the figure, a pit 15 having an uneven shape is formed by injection molding on a substrate, and an unrecorded area 31 where the pit 15 is not formed is included in an information track where the pit is formed. Some have. The key information is recorded in the unrecorded area 31 where the pits 15 are not formed, and becomes the key information recording area.

When such an optical disk is mounted on a recording device, the substrate 12 is irradiated with, for example, a laser beam having an output of 5 mW to reproduce the formed pits.
The unrecorded area 31 is searched by detecting an area in which no signal is detected for a certain period. When the unrecorded area 31 is searched, the laser beam output is increased to about 300 mW, the tracking of the recording device is fixed, and the pit 16 based on the key information is formed in the unrecorded area 31. As described above, the pit 16 formed by the laser beam has a concave shape like the pit 15 formed by injection molding, but a convex rim is formed on an outer peripheral portion thereof, so that the outer appearance differs from the pit 15 ( (See FIG. 2). However, by appropriately selecting the laser beam output and the linear velocity at the time of forming the pits, it is possible to set the level at which the signal quality does not pose a problem. That is, since the recording of the key information is performed in the manufacturing process after the molding of the optical disk substrate, the output of the laser beam used for recording and the linear velocity at the time of recording can be set arbitrarily regardless of the standard as long as the substrate does not significantly deform. Therefore, it is possible to appropriately set an optimum laser light output that provides the best signal quality. The laser beam for forming the pits 16 may be irradiated from either the signal reading surface side or the signal surface side, or from either side. When the key information is recorded in this manner, the management information 2 corresponding to the key information is printed on the label surface, and the optical disc 11 is created.

Next, the case of the optical disk 21 will be described. In a key information recording area of the optical disk 21 before recording of key information (before pit destruction), a plurality of pits having uneven shapes corresponding to a plurality of different key information are formed. As the recording device on which the optical disk 21 is mounted, a recording device having the same laser beam output as the optical disk 11 is used. When such an optical disk is mounted on a recording device,
The key information recording area is searched for while irradiating a laser beam of, for example, 5 mW from the substrate 22 side and reproducing the formed pits 15. When the key information recording area is searched, the laser light output is increased to 300 mW, and the pits other than the specific one or two types of key information are destroyed so as to be unreproducible as shown in FIG. Here, when the deformed portion 23 is formed before the reflective layer 13 is formed, since the light reflectance of the substrate 22 is low, a reproducing operation for searching for a key information recording area and a recording operation for forming the deformed portion 23 are performed. Must be performed without transmitting through the substrate 22.
For this reason, the laser beam is applied from the pit side to the substrate 22 on which the reflective layer 13 is not formed.

After the pits 15 are destroyed in this manner, the management information 2 is printed on the label surface in accordance with the key information constituted by the pits 15 which are correctly read, and the optical disc 21 is created. Since the optical disc 21 destroys the recorded pits 15, the recording accuracy is not required as compared with the case where the pits are recorded as in the case of the optical disc 11, but the storage capacity of the optical disc is equivalent to the pit 15 to be destroyed. Is reduced. However, the key information recording area in which the pits 15 are destroyed is small in view of the storage capacity of the entire optical disk, so there is no problem that the storage capacity is reduced.

In the optical disc 21, any means other than laser light can be used as long as the pits 15 can be destroyed. May be. When flaws are formed in the pits as described above, the pits 15 are preferably destroyed before forming the protective film 14 and after the injection molding of the substrate 12 or after the formation of the reflective layer 13.

On the basis of these methods, the optical disks 11 and 21 were prepared using CDs (compact disks). <Embodiment 1> The pit 15 from the specific address of the CD
A stamper in which an unrecorded area 31 where no is formed is provided by about 1 mm, and a polycarbonate is injection-molded by an injection molding machine using the stamper to form a substrate 12, and an aluminum reflective layer 13 is formed on the substrate 2 by 60 nm. An optical disk was formed by forming the UV resin protective film 14 to a thickness of 10 μm. This optical disk was mounted on a recording device equipped with a semiconductor laser having a wavelength of 780 nm as a light source, and output 5 mW
To reproduce the pit 15 and search for the unrecorded area 31. When the unrecorded area 31 was searched, the pit 16 was formed in the unrecorded area 31 by increasing the laser beam output. At this time, the laser beam output on the pit is 20 mW
/ Μm 2 and a linear velocity of 0.5 m / s. After recording the key information, the management information 2
"ABC-123" is printed with a rubber stamp.
As in the case of a normal CD, the aluminum reflective layer 13 is
The optical disk 11 was formed by forming a protective film 14 having a thickness of 10 μm. When the optical disk 11 was mounted on a normal reproducing apparatus and reproduced, the key information could be detected, but the encrypted information could not be correctly decoded and the information could not be reproduced. Next, the management information “ABC-12” which is attached to a reproducing apparatus having a decoding table in which a decoding method is determined by inputting key information and is printed, is provided.
When the key information based on "3" was input to the reproducing apparatus, the information was correctly decoded and the information could be reproduced.

<Embodiment 2> A key information recording area is provided at a specific address of a CD, a stamper in which a combination of ten numbers is recorded by pits 15 is created in the key information recording area, and polycarbonate is used by using the stamper. Is injection-molded by an injection molding machine into a substrate 22.
An optical disk was formed by forming an aluminum reflective layer 13 of 60 nm and an ultraviolet resin protective film 14 of 10 μm on the optical disk 2. This optical disk was mounted on a recording apparatus equipped with a semiconductor laser having a wavelength of 780 nm as a light source, and the pit 15 was reproduced at an output of 5 mW to search for a key information recording area.
When the key information recording area was searched, the laser output was increased, and the concave and convex shape of the pit containing information of eight of the ten numbers was destroyed. The laser output at this time was 10 mW / μm 2 and the linear velocity was 0.5 m / s. After recording the key information, "ABC-123" is printed with a rubber stamp as management information 2 on the inner peripheral portion of the label surface,
Thereafter, the aluminum reflective layer 13 is formed to have a thickness of 60 nm and the protective film 14 is formed to have a thickness of 10 μm in the same manner as a normal CD, and the
1 was created. When this was mounted on a normal reproducing apparatus and reproduction was performed, the above eight numbers could not be read and only two numbers could be read. In addition, the optical disk 1
As in the case of No. 1, information cannot be reproduced by a normal reproducing apparatus, and the reproducing apparatus is mounted on a reproducing apparatus having a decoding table based on key information and reproduces key information based on the printed management information "ABC-123". When input to the device, playback was performed normally.

As described above, the optical disk 11 of this embodiment
No. 21 cannot be reproduced without key information. As described above, the management information 2 corresponding to the key information is printed on the label surface of the optical disc. This management information 2 is used, for example, as follows. When the user wants to use the software recorded on the optical disc purchased, the user gives the creator (or distributor) of the optical disc to the management information (for example, ABC-1) printed on the optical disc.
When notified of 23) along with the software usage fee, the creator
The key information corresponding to “ABC-123” is provided to the user, and the user can use the software using the key information. In addition, since the owner of the optical disk can be specified by using the management information, for example, the original optical disk used to create the pirated optical disk is specified based on the management information, and the optical disk used as the pirated disk is identified. There is also an effect that the owner can be found and illegal copying of the optical disc is prevented.

When the optical disks 11 and 21 are reproduced, a decoding method that requires key information is required. The decryption method and the key information can be arbitrarily configured. However, the decryption method and the key information may be configured so that the information is correctly reproduced by inputting the key information. For example, since the optical discs 11 and 21 of this embodiment are manufactured using a common stamper, information other than the key information may be set to a decoding method that can be reproduced by a normal reproducing apparatus. In this case, for example, the key information recorded on the optical disc is collated with the key information specified by the management information so that the recorded information can be reproduced.

Since the decoding method for reproducing the information of the optical disks 11 and 21 is different from the decoding method of a normal reproducing apparatus, a hardware (computer or the like) using the information of the reproducing apparatus or the optical disk is used. It is necessary to prepare this decoding method in advance. This decoding method is, for example, recorded on an optical recording medium so that it can be reproduced even by ordinary decoding, supplied by another recording medium such as a magnetic disk, or prepared in a reproducing apparatus. Just do it. The key information does not need to be different for each optical disc, but can be different for several, several tens or several hundreds of optical discs. Further, a plurality of key information recording areas may be provided on the optical disc. For example, if a plurality of software programs are recorded on the optical disc, a number corresponding to the software program or more may be provided. Further, the present invention is naturally applicable to other optical recording media such as a card type and a tape type as well as an optical disk.

[0029]

As described above, according to the optical recording medium of the first and second aspects of the present invention, the whole or a part of the uneven shape is destroyed so that the recorded information cannot be reproduced. Since the area composed of the pits and the pits in which the irregularities are not destroyed is provided at a predetermined position, even if the stamper for injection-molding the light-transmitting substrate is common, one piece of information of the optical recording medium can be obtained. It is possible to make the difference in a small unit such as several sheets, several tens sheets, and several hundred sheets. As a result, there is an effect that an optical recording medium having excellent security can be provided at low cost.

[Brief description of the drawings]

FIG. 1 is a diagram showing an appearance of an optical disc according to an embodiment of the present invention.

FIG. 2 is a diagram showing a cross-sectional view in the track direction of a key information recording area of the optical disc according to the first embodiment of the present invention.

FIG. 3 is a diagram showing a cross-sectional view in the track direction of a key information recording area of an optical disc according to a second embodiment of the present invention.

FIG. 4 is a diagram showing a key information recording area of the optical disc in FIG. 2 before recording key information.

[Explanation of symbols]

 1,11,21 Optical disk (optical recording medium) 2 Management information 12,22 Substrate (light transmitting substrate) 13 Reflective layer 14 Protective film 15,16 Pit 17,24 Rim 23 Deformation part

Claims (2)

[Claims] 1. A light-transmitting substrate having a plurality of tracks formed with a pit row having an uneven shape corresponding to information over a plurality of tracks, the light-transmitting substrate having at least a reflection layer made of a light-reflective substance. In an optical recording medium from which the information is read out by detecting the unevenness of the pit row by using a laser beam emitted from the side opposite to the side on which the row is formed, the recorded information cannot be reproduced. An optical recording medium characterized in that a region composed of pits in which the whole or a part of the pit row having an irregular shape is destroyed by using a laser beam and pits in which the irregular shape is not destroyed is provided at a predetermined position. . 2. The optical recording medium according to claim 1, wherein information relating to the presence of the destroyed pit is recorded in a lead-in area.