JP2008293645A - Authentication system of magnetic recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a system for authenticating a magnetic recording medium. <P>SOLUTION: The authentication system has a magnetic recording medium, a recording and reproducing device and an external data base. The magnetic recording medium is provided with a substrate, recording tracks, a track separating part physically separating tracks, a magnetic recording area formed in the tracks and formed by using a magnetic recording layer in which information can be magnetically recorded, a magnetically deficient part which is formed in the peculiar position of the recording track so as to separate the magnetic recording area and in which information can not be magnetically recorded and ID information specifying presence of the magnetically deficient part. The recording and reproducing device is provided with an acquiring part acquiring position specifying information for specifying the position of the magnetically deficient part on the basis of the ID information, a recording and reproducing part and an authenticating part extracting the position of the deficient part from information reproduced from the recording and reproducing part and comparing the extracted deficient position and position specifying information with each other to authenticate the magnetic recording medium. The external database stores the position specifying information compatible with the ID information and specifying the position of the deficient part. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

    The present invention relates to a recording medium, a recording / reproducing apparatus, and a recording / reproducing method, and in particular, for example, a recording medium for managing copy protection or accessibility of contents stored in a recording medium, and using this recording medium The present invention relates to an authentication method and an authentication system capable of executing this authentication method.

    With the spread of digital data, the importance of copy protection technology for copyright protection of music software, video software, application software, etc. is increasing. Typical examples of software that particularly requires copy protection include a DVD (Digital Versatile Disk) video disk or a DVD-ROM disk that employs a digital recording method. Conventionally, encryption technology has been used for copy protection for video software for digital recording.

  The copy protection method using the encryption technique functions effectively for a DVD video disk or a DVD-ROM disk in which already encrypted data is recorded. However, in the case of a DVD-RAM in which a user can newly record data, the following problem occurs.

  (1) It is difficult to manage the “encryption key” required for encryption.

  (2) In a data recording / reproducing apparatus (for example, a DVD-RAM recorder capable of digitally recording / reproducing like a widely used analog video cassette recorder), a strong encryption process is performed. It is difficult and the code is easily broken.

  (3) When the data recording / reproducing apparatus can perform encryption and decryption, the data once created and encrypted by the user is decrypted by another data recording / reproducing apparatus and then encrypted again. By performing the processing, the data content desired to be copy protected is easily copied.

  Because of these problems, it is difficult for a digital video data recording / reproducing apparatus to effectively function copy protection using a conventional encryption technique. Also, if the DVD-RAM drive side tries to perform copy protection processing on the DVD-RAM data recording medium by a unique method, the data recording medium is reproduced by the DVD-ROM drive, or conversely, the DVD-ROM. There is a problem that the copy protection processing circuit becomes complicated when the disc is reproduced by a DVD-RAM drive. This also increases the product cost of the DVD-RAM drive.

  The inventor of the present invention has already provided an authentication area in the recording medium, a RAM bit in which data can be rewritten in accordance with the first write condition, and a ROM in which data cannot be written under the first write condition. Patent Document 1 proposes a recording medium that can realize copy protection for recorded data by arranging bits.

On the other hand, in recent years, in order to cope with higher density of magnetic recording media, adjacent magnetic recording tracks are separated by a groove or a guard band made of a non-magnetic material so as to reduce magnetic interference between adjacent tracks. Discrete track media is gaining attention. When manufacturing such a discrete track medium, patterns of a magnetic material and a non-magnetic material forming a magnetic recording track are formed by an imprint method using a stamper.
JP2004-39006

  According to the recording medium disclosed in Patent Document 1, reliable copy protection can be realized, but copy protection by a simpler method is required.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a recording medium, an authentication method, and an authentication system capable of performing safe and reliable copy protection for recorded data and preventing unauthorized copying. And providing a restoration system.

According to this invention,
A substrate,
A recording track extending on the substrate surface so as to be arranged adjacent to each other;
A track separation unit that physically separates the adjacent recording tracks from each other;
A magnetic recording region formed of a magnetic recording layer formed on the recording track and capable of magnetically recording information;
A magnetic defect formed on the recording track so as to separate the magnetic recording area, and magnetic recording of information is impossible;
A magnetic recording medium is provided.

Moreover, according to this invention,
A substrate,
A recording track extending on the substrate surface so as to be arranged adjacent to each other;
A track separation unit that physically separates the adjacent recording tracks from each other;
A magnetic recording dod formed on a magnetic recording layer periodically formed on the recording track and capable of recording information magnetically;
A magnetic defect formed on the recording track so as to separate a periodic arrangement of the magnetic recording dods, and magnetically unable to record information;
A magnetic recording medium is provided.

Furthermore, according to the present invention,
A recording track extending on the surface of the substrate so as to be adjacent to each other, a track separation part for physically separating the recording tracks adjacent to each other, and a magnetic information formed on the recording track. A magnetic recording area formed of a magnetic recording layer capable of recording a magnetic recording layer, and a magnetic defect portion formed on the recording track so as to separate the magnetic recording area and incapable of recording information magnetically. Medium,
An acquisition unit for acquiring position specifying information capable of specifying the position of the missing part;
A recording / reproducing unit for recording information on the recording layer of the magnetic recording medium and reproducing information from the recording layer;
An authentication unit for extracting the position of the missing portion from the information reproduced from the recording / reproducing unit, comparing the extracted defect position and the position specifying information, and authenticating the magnetic recording medium;
A recording / reproducing apparatus is provided.

Furthermore, according to the present invention,
A recording track extending on the surface of the substrate so as to be adjacent to each other, a track separation part for physically separating the recording tracks adjacent to each other, and a magnetic information formed on the recording track. A magnetic recording area formed of a magnetic recording layer capable of recording a magnetic recording layer, and a magnetic defect portion formed on the recording track so as to separate the magnetic recording area and incapable of recording information magnetically. In a recording / reproducing method for recording information on the recording layer of a medium and reproducing information from the recording layer,
Acquiring position specifying information that can specify the position of the defect,
A recording / reproducing method is provided, wherein the position of the defect portion is extracted from the reproduction information, and the magnetic recording medium is authenticated by comparing the extracted defect position and the position specifying information.

  In the magnetic recording medium described above, the magnetic recording layer extends on the surface of the substrate, a magnetic recording track is defined in the magnetic recording region, and a track separation unit that physically separates the magnetic recording tracks from each other includes the magnetic recording medium. A track may be formed side by side on the substrate, and the magnetic defect portion may be provided in the magnetic recording track.

  Further, the magnetic recording track may be divided at a constant interval with respect to the track direction, and the divided portion may be provided with a magnetic dividing portion that cannot magnetically record information. When information is recorded on the medium by the recording / reproducing head, the recording / reproducing head performs information recording for each magnetic recording track divided by a magnetic dividing unit at a constant period. That is, the period at which the magnetic recording track is divided corresponds to one unit of information recorded by the recording / reproducing head.

  In the above magnetic recording medium, the magnetic recording track is divided at a constant period by the magnetic dividing portion, which is different from the magnetic defect portion of the present invention. The magnetic division parts are arranged at a constant period along the magnetic recording track, whereas the magnetic defect parts are not arranged at a constant period and are scattered at unique positions corresponding to the ID information.

  According to the present invention, when information recorded in a recording apparatus is copied by a general user, it is possible to select original recording and copy recording using defect information, and authentication or copy protection can be performed. Become.

  The inventor has focused on discrete track recording media and has come to the idea that with the structure of a discrete track medium, copy protection can be realized in a simple manner while reducing the manufacturing cost of the recording medium. . Further, based on this idea, not only a discrete track recording medium but also a defect portion is provided in a track of the recording medium, and ID information for specifying the arrangement of the defect portion corresponds to the arrangement of the defect portion. In some cases, the idea is that the content or program recorded on the recording medium can be guaranteed to be original.

  Hereinafter, a recording medium, an authentication method, an authentication system, and a restoration system according to an embodiment of the present invention will be described with reference to the drawings as necessary.

  FIG. 1 is a plan view schematically showing a recording area in a magnetic recording medium according to an embodiment of the present invention.

  As shown in FIG. 1, on a recording medium, for example, a magnetic disk, magnetic recording tracks 2 are arranged adjacent to each other and extend in the recording area along the track direction (recording / reproducing direction) RW. The magnetic recording track 2 is physically separated from each other by a nonmagnetic separation portion 6 formed of a nonmagnetic material layer extending along the magnetic recording track 2 to form a discrete track on the magnetic disk. On the magnetic recording track 2, a plurality of strip-like magnetic layers capable of magnetically recording / reproducing data are formed as magnetic recording regions. If the recording medium shown in FIG. 1 is a disk-shaped magnetic disk described with reference to FIG. 4, the track direction RW corresponding to the recording / reproducing direction is determined in the direction along the circumference of the disk. Yes. In a normal disk-like disk, the rotation direction is set to the recording / reproducing direction, and a magnetic recording track 2 as a magnetic layer extends along the circumferential direction which is the rotation direction. As already known, patterns of the magnetic layer and the nonmagnetic layer are formed by the imprint method using a stamper, and are determined on the magnetic recording track 2 and the nonmagnetic separation portion 6.

  As shown in FIG. 1, the magnetic recording track 2 of the recording medium includes a defect portion (defect segment) 8 in which the recording layer is lost and the recording area is separated, and the defect portion (defect segment) 8 is the recording medium. It is provided in a specific area 4 of the specific magnetic recording track 2 inside. The defect portion 8 may be formed as a non-magnetic segment similar to the non-magnetic separation portion 6 or is formed of a magnetic material, but a recess is formed in the band of the magnetic layer and the defect portion 8 is formed. It may be defined in a part (segment) 8.

  It should be noted that the nonmagnetic separation portion 6 may be formed of a magnetic material in the same manner as the defect portion (segment) 8 and may be defined as the nonmagnetic separation portion 6 by forming a recess in the band of the magnetic layer. is there.

  When the magnetic recording track 2 is searched with a magnetic head (not shown), the defect 8 formed as a non-magnetic segment is not detected magnetically, and a recess is formed in the band of the magnetic layer. Since the distance between the defect portion 8 and the magnetic head is increased, the defect portion 8 is not substantially magnetically detected.

  The recording layer of the magnetic recording track 2 is not limited to the case where the defect portion 8 is formed in the magnetic recording track 2 extending in a strip shape as shown in FIG. 1 but along the track direction RW as shown in FIG. A structure (patterned medium structure) in which the magnetic dots 12 are divided and periodically arranged may be provided. That is, the magnetic recording track 2 may be defined as a track in which a large number of magnetic dots 12 are periodically arranged along the track direction RW, and a part 18 of the periodically appearing magnetic dots 12 may be lost. . That is, the arrangement of the periodic magnetic dods 12 may be separated. In the region of the magnetic recording track 2 in which the magnetic dots 12 are periodically arranged, a nonmagnetic separation stripe 10 formed of a nonmagnetic material layer is provided in the same manner as the nonmagnetic separation portion 6. The dots 12 are alternately arranged on the area of the magnetic recording track 2. Further, the missing portion 8 on the magnetic recording track 2 corresponds to at least a portion where the pair of separation stripes 10 and the magnetic dots 12 between the pair of separation stripes 10 are to be originally formed. Similarly, it is formed of a nonmagnetic layer. The separation stripe 10 and the defect portion 8 are formed of a magnetic material, but may be defined as the defect portion 8 by forming a recess in the band of the magnetic layer.

  In the recording medium shown in FIGS. 1 and 2, the magnetic recording track 2 is formed in a discrete track structure separated from each other by a separation stripe 10, but the separation stripe 10 is not provided as shown in FIG. Even if a defect portion 8 is provided in a specific region 4 of a general magnetic recording medium in which a magnetic layer is formed on the entire surface of the recording medium and the magnetic tracks 2 are arranged in parallel along the magnetic recording direction RW. good.

  In the disk-shaped disk 20 shown in FIG. 4, ID information 22 that specifies the presence or absence of the missing portions 8 and 18 in the specific area 4 is recorded in the sector area of the management area of the disk 20. In the ID information 22 itself, a recording layer missing position, for example, a track address and a sector address are not recorded. The ID information 22 describes that there are missing portions 8 and 18 and a code unique to the arrangement of the missing portions 8 and 18.

  Information that can identify the positions of the missing portions 8 and 18 of the recording layer is stored in a database outside the recording / reproducing apparatus as will be described later. However, the information is recorded on the recording medium itself or on this recording medium. You may store in the memory incorporated in the recording / reproducing apparatus which reproduces | regenerates information from a recording medium. The information that can specify the positions of the missing portions 8 and 18 of the recording layer is not limited to the case where the position information of the missing portions of the recording layer is listed, such as the track address and the sector address, but the position of the missing portion of the recording layer described later. ID information such as an address number for accessing the external database in which the information is recorded and reading out the position information of the missing portion may be used. Further, the ID information 22 and the position information of the missing part may be recorded in the magnetic recording area, for example, as an array (pattern) of the missing parts 8 and 18 in the management area. In other words, the ID information 22 and the position information of the missing portion may be recorded in a pattern generated by the presence or absence of a recording layer in the magnetic recording area or an arrangement (pattern) of a portion where magnetic recording is impossible.

  Next, an authentication method in the recording / reproducing apparatus according to the embodiment of the present invention will be described with reference to FIGS.

  5A to 5C show the structure of the magnetic recording track shown in FIG. 1, the sequence data as information to be recorded on the magnetic recording track, and the recording state of the sequence data on the recording medium. Shown schematically. As shown in FIG. 5A, in a certain recording area 4, the magnetic track 2 has a partial defect portion 8, and as shown in FIG. It is assumed that sequence data composed of binary values such as “0” and “0” or “+1” and “−1” is recorded. In FIG. 5B, “−1” is shown in white and “+1” is shown in black for easy understanding. A recording head (not shown) is supplied with sequence data as magnetic information as shown in FIG. 5B, and this information is recorded on the magnetic recording track 2 shown in FIG. 5A one after another. At the time of this information recording, information recording is performed regardless of the position of the defect on the recording medium. However, since no information is recorded on the defect portion 8 on the magnetic track 2, a recording medium as shown in FIG. Above, partial information corresponding to white, black, and white, for example, (−1, +1, −1), as indicated by the arrow 28, is recorded in the missing portion 8 without being missing. Therefore, recording is performed on the magnetic track 2 in a state where a part of the sequence data as shown in FIG. 5B is missing.

  FIG. 6 is a flowchart showing a method for reproducing and authenticating the recorded information as shown in FIG.

  At the start of information reproduction, the ID information 22 previously recorded in the management area on the recording medium is read by the reproducing magnetic head as shown in step S30. The defect information ID 22 read from the reproducing magnetic head is temporarily stored in RAM (not shown) as management data as shown in step S40. After all the management information is read, the data area is searched by the reproducing magnetic head, and object data such as programs, audio data or video data is read by the reproducing magnetic head.

  At the time of reproducing information including such management information and object data, the detection signal from the reproducing magnetic head in step S30 is subjected to processing such as a gain amplifier, a filter, and peak detection (not shown) as shown in step S32. As shown in step S34, error correction is performed and converted into restored data, which is output as shown in step S36.

  Here, error correction is performed by an ECC (Error Correction Code) circuit. For error correction, for example, there is a method of using encoding when recording information. The encoding includes, for example, Reed-Solomon code, convolutional code, concatenated code, Viterbi decoding, turbo code, LDPC code (low density parity check codes), etc. In general, any code can be used for a data block with k bits. On the other hand, redundant data is added by encoding to obtain an n-bit (n> k) error correction code. This error correction code has m-bit error correction capability for a data block of k bits. That is, even if data is erroneously read up to m bits in a k-bit data block, the original data can be correctly restored by error correction. The value of the error correction capability m for the number of bits k and the code length n varies depending on the coding scheme. The missing portion according to the above-described embodiment works effectively as long as the missing data amount does not exceed the value of the error correction capability m. Therefore, the specific method of encoding is not limited in the present invention. For example, the Reed-Solomon code uses a j × 2 byte ECC code to have a correction capability of j bytes. As a matter of course, it is preferable to give the missing data (binary data) that can be stored in the missing portion 8 in each track as many as the Reed-Solomon code correction capability does not exceed. Even if the recorded information is lost in the missing part 8, the recorded information can be restored. In this sense, it is necessary that the missing portion 8 be arranged on the magnetic recording track 2 so that the data lost at the missing portion remains within the range of the error correction capability.

  The error-corrected restored data is supplied to the reproduction processing unit or another data processing unit, and is transferred to an error position confirmation process as shown in step S38. In this step S38, the position of the error corresponding to the restored data position is specified by comparing the restored data with the detection signal before error correction. That is, the error position is specified by comparing the restored data with the data before restoration. In addition to the data that should have been recorded in the missing part 8, the specified error includes a defect on the disc or recording / reproduction data that occurred accidentally at the time of data processing. Corresponding errors are extracted in this step S38. In step S38, an error other than an error caused by the defective portion 8, for example, an error having a specific bit length or more may be excluded as an error caused by the defective portion 8.

  The extracted error is converted into error position data, and the error position is specified. That is, the extracted error position data is stored in a RAM (not shown) as the position on the disk where the error has occurred. The position on the disk where the error occurred is specified as a track address and a sector address on the disk.

  If the recorded information is an image or music, the reproduction information can be browsed to some extent without completely restoring the information by error correction. In such a case, the information error position may be determined by an error detection mechanism such as parity check instead of error correction, and may be grasped as the positions of the missing portions 8 and 18 of the recording layer.

  Next, in step S42, when the missing information ID stored in the RAM is referred to in step S40 and it is confirmed that the disk has the defective part 8, the disk is defective based on this ID. 8 is confirmed. In step S42, the defect information ID is sent to the defect position verification database outside the recording / reproducing apparatus. In step S44, defect position verification information is specified with reference to the defect information ID. When the defect position collation information is acquired by the recording / reproducing apparatus, it is confirmed with reference to the defect position collation information whether the extraction error position data is included therein. As shown in step S46, when all or most of the extracted error position data is included in the defect position verification information, the content data such as the program or video recorded on the disc is authentic data. The original data is confirmed. When the recorded data is confirmed to be original and approved, the output from step S36 is decoded by a decoder (not shown), or another processing unit (not shown), for example, decrypts a cipher. Is processed as original data by the decoding unit.

Here, the external defect location verification database corresponds to a database of a program provider (content provider) connected to the Internet, and the recording / playback apparatus is an apparatus used by a user who contracts supply of content with the program provider. Is applicable. The user who is a contractor corresponds to the case of notifying the program provider of the position information of the defective portion 8 and receiving the defect information ID from the program provider.

  On the other hand, when the information recorded on the original medium is copied to a different medium, the information to be copied is only the magnetization information, and the actual missing portion does not exist on the copy medium. Therefore, when the reading error position is compared by the above method, the reading error does not occur on the copied medium, and there is a state in which no error occurs at the missing position recorded in the recording area. In this case, since it is determined that the recorded information is not original, for example, copy protection such as invalidating the recorded information can be performed. Copy protection can be strengthened by using information encryption technology.

  In the above description, it is assumed that the defect position verification information referred to by the defect information ID is stored in a database outside the recording / reproducing apparatus, but the memory in which the defect position verification information is provided in the recording / reproducing apparatus. For example, it may be stored in a ROM or a non-volatile memory and referred to by a missing information ID.

  When the recording area of the defect position verification information is in the recording / reproducing apparatus, authentication can be performed even if the recording apparatus is not connected to any external peripheral device. On the other hand, if there is a recording area in which defect location verification information is recorded outside the device owned by the user, for example, on the network, the recording / reproducing apparatus is generally used if a certain user authentication mechanism is provided in this recording area. It becomes impossible for the user to change the defect position without permission, and more robust copy management can be realized.

Example 1
Next, a copy protection method using an encryption technique will be described as an embodiment of the present invention.

  A copy protection method in the case where some information is copied from the server and recorded in the recording apparatus described above will be described in detail.

  In this copy protection method, it is assumed that a defect portion 8 having a size of n bits for each sector is artificially given to the recording layer in the magnetic recording medium provided in the recording apparatus. In addition, when recording on a magnetic recording medium, an ECC code having an error correction capability of m bytes larger than n is attached. It is assumed that the defect position artificially formed in each sector is recorded on the server and stored together with the ID for each recording medium.

  When information such as content data stored in the server is recorded on a recording device of a specific user (simply referred to as a specific recording device), the information is encrypted by the server and a decryption key is created. Next, the server receives the ID of the copy destination medium, and sends the encrypted information to a specific recording device. On the specific recording apparatus side, the encrypted information is recorded on the recording medium together with the ECC code.

  Next, it is assumed that the encrypted information is copied from a specific recording device to another unauthorized recording device (referred to simply as another recording device) while being encrypted. At this time, it is assumed that the medium ID of a specific recording device is also read and copied to another recording device. However, it is assumed that a defect position in a medium of a specific recording apparatus and another recording apparatus is different.

  When reproducing information recorded in a specific recording device, first, the information is restored by the specific recording device via the ECC circuit. Since the number n of artificially formed defects does not exceed the error correction capability m, the information recorded in the sector including the defect is also correctly error-corrected and output. Next, when restoring the output encrypted information, the part for which the error was corrected by the ECC circuit and the medium ID of the specific recording apparatus are transmitted to the server side. On the server side, the received error part and medium ID are checked against defect information stored on the server side. When all defective parts stored on the server side are included in the sent error part, the server authenticates this specific recording apparatus as a regular recording apparatus and transmits an encryption key. Therefore, this specific recording apparatus can receive the encryption key (decryption key) and restore the encrypted information using this key.

  On the other hand, in the other recording apparatus in which the information and the medium ID are copied, when using the same authentication method as described above, the position where error correction is performed, that is, the artificially formed defect position is the specific recording apparatus. Is different. Therefore, since the missing position stored in advance on the server side is different from the error position sent from the other recording device, the other recording device is not authenticated to the regular recording device and the encryption key is not transmitted. It will be. Accordingly, the encrypted information cannot be restored by another recording device copied with information from the specific recording device. With the above operation, the copy protection function can be operated reliably.

(Example 2)
7 (a) to 7 (c) show a recording / reproducing method and an authentication method according to another embodiment of the present invention. FIG. 7A shows the structure of the magnetic recording track shown in FIG. 1, FIG. 7B shows sequence data as information to be recorded on the magnetic recording track, and FIG. Shows schematically the recording state of the sequence data on the recording medium.

  At the time of information recording, as already described, first, the defect position of the defect portion 8 as shown in FIG. 7A is grasped from the medium defect position ID information and the defect position recording area 4. Next, when the sequence data as shown in FIG. 7B is recorded, the sequence data is recorded while avoiding the missing position of the missing portion 8 as shown in FIG. 7C. Therefore, on the magnetic recording track 2, the sequence data is separated and recorded avoiding the missing portion 8. At the time of information reproduction, similarly, the defect position of the defect portion 8 as shown in FIG. 7A is grasped from the medium defect position ID information and the defect position recording area 4, and as shown in FIG. Sequence data is reproduced while avoiding 8 missing positions. Therefore, the sequence data is reproduced normally. When recording information, the recorded information and the ID of the medium on which this information is recorded are recorded in the management area of the recording medium.

  However, when information is copied to a recording medium of another recording device having a defect position, the defect position when reproducing the recorded information and the defect position specified by the ID of the recording medium recorded in advance are Is different. Accordingly, it is found that the original recording is not performed. Thereby, for example, copy protection such as invalidating recorded information can be realized.

(How to create media)
The recording medium shown in FIG. 1 can be preferably manufactured through one of the following first and second manufacturing methods.

1st manufacturing method (magnetic body processing type)
First, a defect position provided on the recording medium and ID information related to the defect position are created and stored in the storage device as defect information.

  Next, an imprint stamper is manufactured as shown in FIGS.

  In the imprint stamper creation process, as shown in FIG. 8A, an imprint stamper substrate 50 having a flat surface, preferably a Si substrate or a glass substrate, is prepared. A resist 52 for electron beam drawing is applied. A pattern corresponding to the magnetic recording track 2 as shown in FIG. 1 is drawn on the resist 52 by an electron beam, and the resist 52 is developed and the pattern is uneven as shown in FIG. 8B. As shown in FIG. A drawing apparatus for drawing a pattern draws the pattern of the magnetic recording track 2 over the entire circumference of the resist, writes a code corresponding to the ID information in a management area on the recording medium in accordance with the ID information, and on the recording medium in accordance with the defect position. The missing portion 8 is written in the specific area 4. Therefore, a groove corresponding to the magnetic recording track 2, a concavo-convex corresponding to ID information, and a convex corresponding to the missing portion 8 are formed in the groove corresponding to the magnetic recording track 2 on the developed resist 52. .

  Thereafter, as shown in FIG. 8C, a stamper 54 is formed on the resist 52 by electroforming. The material of the stamper 54 is preferably Ni, but is not limited thereto. On the surface of the stamper 54, the unevenness of the resist 52 is reversed and transferred. Although not shown, the stamper may be formed by etching the resist 52 shown in FIG. 8B and transferring the irregularities of the resist 52 to the substrate 50 as irregularities.

  The imprint stamper 54 is prepared by the above process. A magnetic recording medium is manufactured through the steps shown in FIGS. 8D to 8G using the imprint stamper 54.

  In the magnetic recording medium manufacturing process, a medium substrate 60 is prepared as shown in FIG. 8D, and a magnetic recording magnetic layer 62 is formed on the medium substrate 60. The magnetic layer 62 is preferably made of a material suitable for perpendicular magnetic recording, and a recording ferromagnetic film is formed as the magnetic layer 62. Preferably, an underlayer made of a soft magnetic material is formed under the recording ferromagnetic film, and the magnetic layer 62 is constituted by a two-layer structure of a soft magnetic underlayer and a ferromagnetic film. On the magnetic layer 62, as shown in FIG. 8D, a resist film 64 for imprinting is further applied to prepare a substrate structure 66 provided with the resist film 64.

  Next, an imprint stamper faces the substrate structure 66 having the resist film 64 shown in FIG. 8D, and the imprint stamper is pressed against the resist film 64 based on the imprint method. A pressure is applied between the substrate structure 66. Accordingly, the uneven pattern on the surface of the imprint stamper 54 is transferred to the surface of the resist film 64. After this transfer, the imprint stamper 54 is peeled from the substrate structure 66 shown in FIG. 8D, as shown in FIG.

  Further, as shown in FIG. 8F, the resist film 64 on which the concavo-convex pattern is formed is etched so that the same concavo-convex pattern is formed on the magnetic layer 62 of the substrate structure 66. That is, as shown in FIG. 8F, the magnetic layer 62 is patterned according to the concavo-convex pattern on the surface of the resist layer.

  Thereafter, as shown in FIG. 8G, a carbon protective film 68 is provided on the substrate structure 66 on which the magnetic pattern is formed on the magnetic layer 62, and a lubricant is applied onto the carbon protective film 68. Thus, the magnetic recording medium is completed. Here, the lubricant is provided in order to make the relative running smoothly on the magnetic recording medium on which the magnetic head rotates.

  By the method described with reference to FIGS. 8A to 8G, a magnetic track and a non-magnetic pattern having a defect portion in the recording layer are formed as shown in FIG. 1 or FIG. A recording medium is produced. This recording medium is incorporated into a recording apparatus by a method similar to the conventional method.

Second manufacturing method (substrate processing mold)
In the twenty-second manufacturing method, as shown in FIGS. 9A to 9C, the imprint stamper performs the steps shown in FIGS. 8A to 8C similar to those in the first manufacturing method. Created after. Accordingly, the description of the steps shown in FIGS. 9A to 9C will be given the same reference numerals as those used in the steps shown in FIGS. 8A to 8C, and description thereof will be omitted.

  Next, as shown in FIG. 9D, a medium substrate 60 is prepared, and an imprint resist film 64 is applied on the medium substrate 60 to prepare a medium substrate structure 70. As shown in FIG. 8E, the medium substrate structure 70 faces the imprint stamper 54, and the imprint stamper 54 is pressed against the resist film 64 based on the imprint method, so that the medium substrate structure 70 and the imprint stamper are pressed. 54, pressure is applied. Accordingly, the uneven pattern on the surface of the imprint stamper 54 is transferred to the surface of the resist film 64. After this transfer, the imprint stamper 54 is peeled off from the resist film 64.

  Further, as shown in FIG. 9 (f), a similar uneven pattern is formed on the substrate 60 of the substrate structure 66 by etching the resist film 64 on which the uneven pattern is formed. Thereafter, as shown in FIG. 9G, a magnetic layer 72 for magnetic recording is formed on the substrate 60 on which the concavo-convex pattern is formed. The magnetic layer 62 is preferably made of a material suitable for perpendicular magnetic recording, and a recording ferromagnetic film is formed as the magnetic layer 62. Preferably, an underlayer made of a soft magnetic material is formed under the recording ferromagnetic film, and the magnetic layer 62 is constituted by a two-layer structure of a soft magnetic underlayer and a ferromagnetic film. Finally, a carbon protective film is provided on the magnetic layer 62 on the substrate 60 having the concavo-convex pattern, and a lubricant is further applied to complete the recording medium.

  By the manufacturing method described above, a recording medium having a recording layer defect portion as a magnetic concave pattern on the surface of the recording layer can be produced. In this recording medium, data can be recorded by a recording apparatus as in the conventional case.

1 is a plan view schematically showing a recording area in a magnetic recording medium according to an embodiment of the present invention. FIG. 6 is a plan view schematically showing a recording area in a magnetic recording medium according to another embodiment of the present invention. It is a top view which shows roughly the recording area in the magnetic recording medium based on other embodiment of this invention. FIG. 2 is a plan view schematically showing a magnetic disk as a magnetic recording medium on which the magnetic track shown in FIG. 1 is formed. (A)-(c) is the schematic for demonstrating the reproducing method and authentication method which concern on the Example of this invention, Comprising: (a) is the outline of the structure of the magnetic recording track | truck shown by FIG. FIG. 4B is a schematic diagram showing sequence data as information to be recorded on the magnetic recording track, and FIG. 4C is a schematic diagram showing a recording state of the sequence data on a recording medium. It is. It is a flowchart which shows the reproduction | regeneration method and authentication method of the sequence data recorded as shown in FIG.5 (c). (A)-(c) is the schematic for demonstrating the reproducing | regenerating method and authentication method based on another Example of this invention, Comprising: (a) is the structure of the magnetic recording track | truck shown by FIG. FIG. 4B is a schematic diagram showing sequence data as information to be recorded on the magnetic recording track, and FIG. 4C shows a recording state of the sequence data on a recording medium. It is a schematic diagram. (A)-(g) is sectional drawing which shows roughly the process in the method of manufacturing the recording medium shown by FIG. (A)-(g) is sectional drawing which shows schematically the process in the other method of manufacturing the recording medium shown by FIG.

Explanation of symbols

2. . . 3. magnetic recording track; . . 5. Specific recording area, . . Non-magnetic separation part, 8, 18. . . Deficient part, 10. . . Nonmagnetic separation stripes, 12. . . Magnetic dodd, 22. . . ID information, 50. . . Substrate, 52. . . Resist, 54. . . Imprint stamper, 60. . . Medium substrate, 62. . . Magnetic layer, 64. . . Resist film

Claims (1)

Formed on the recording track, a recording track extending on the surface of the substrate so as to be arranged adjacent to each other, a track separation unit for physically separating the recording tracks arranged adjacent to each other, and a magnetic field Magnetic recording area formed by a magnetic recording layer capable of recording information and a magnetic defect that is formed at a specific position of the recording track so as to separate the magnetic recording area and cannot record information magnetically And a magnetic recording medium comprising ID information for specifying the presence or absence of the magnetic defect portion,
An acquisition unit that acquires position specifying information that can specify the position of the magnetic defect portion based on the ID information, and a recording / reproducing unit that records information on the recording layer of the magnetic recording medium and reproduces information from the recording layer And an authentication unit that authenticates the magnetic recording medium by extracting the position of the defect from the information reproduced from the recording / reproducing unit and comparing the extracted defect position with the position specifying information. A recording / playback device;
A magnetic recording medium authentication system comprising: an external database storing position specifying information corresponding to the ID information and capable of specifying the position of the defect portion.

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