JP2012033226A - Optical information recording method, reproduction method and recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To retain reliability against flaws and defects, to keep high capacity efficiency of user data and to maintain easiness of updating of management information, when recording data on a holographic recording medium.SOLUTION: In the holographic recording device, error correction codes across multiple books are added to user data. And the management information is multiple written on two or more different books.

Description

  The present invention relates to an optical information recording method, a reproducing method, and a recording apparatus.

  Currently, it is possible to commercialize optical discs with a recording density of about 50 GB even for consumer use by the Blu-ray Disc (BD) standard and the High Definition Digital Versatile Disc (HD DVD) standard using a blue-violet semiconductor laser. It has become.

  In the future, it is desired to increase the capacity of an optical disk to the same level as an HDD (Hard Disc Drive) capacity of 100 GB to 1 TB.

  However, in order to realize such an ultra-high density with an optical disk, a new storage technology different from the trend of the conventional high-density technology due to the shorter wavelength and the higher objective lens NA is required. .

  While research on next-generation storage technology is underway, hologram recording technology that records digital information using holography is attracting attention.

  The hologram recording technique is a method in which a signal light having page data information two-dimensionally modulated by a spatial light modulator and a reference light are superimposed inside the recording medium, and an interference fringe pattern generated at that time causes the inside of the recording medium. This is a technique for recording information by causing refractive index modulation in the optical disk.

  When reproducing the information, if the recording medium is irradiated with the reference light used for recording in the same arrangement, the hologram recorded in the recording medium acts like a diffraction grating to generate diffracted light. This diffracted light is reproduced as the same light including the recorded signal light and phase information.

  The reproduced signal light is detected two-dimensionally at high speed using a photodetector such as a CMOS or CCD. Thus, in hologram recording, two-dimensional information can be simultaneously recorded / reproduced by one hologram, and a plurality of page data can be overwritten at the same location, so that large-capacity and high-speed information can be recorded / reproduced. It is valid.

  As a hologram recording technique, for example, there is JP-A-2004-272268 (Patent Document 1). In this publication, a signal beam is condensed on an optical information recording medium by a lens, and simultaneously, a hologram is recorded by irradiating and collimating a reference beam of a parallel beam, and further determining the incident angle of the reference beam on the optical recording medium. A so-called angle multiplex recording method is described in which multiplex recording is performed by displaying different page data on a spatial light modulator while changing. Furthermore, in this publication, the distance between adjacent holograms can be shortened by condensing the signal light with a lens and providing an aperture (spatial filter) in the beam waist, which is compared with the conventional angle multiplex recording system. A technique for increasing the recording density / capacity is described.

  Further, as a hologram recording technique, for example, there is WO2004-102542 (Patent Document 2). In this publication, in one spatial light modulator, light from an inner pixel is signal light, light from an outer ring-shaped pixel is reference light, and both light beams are condensed on an optical recording medium with the same lens. An example is described in which a shift multiplexing method is used in which a hologram is recorded by causing signal light and reference light to interfere with each other in the vicinity of the focal plane of the lens.

  According to the standard ECMA-377 (Non-Patent Document 1), which is standardized as one of the lens shift multiplexing systems, an LDPC code (LowDencity) is used as an error correction code for protecting data reliability. It is described that high reliability is maintained by encoding by Parity-check Code) and encoding by Reed-Solomon code between pages.

  In addition, a defect location indicating a replacement positional relationship is recorded as management information, and the defect information indicating the replacement positional relationship is recorded as management information. In particular, in a disc that can be recorded once, the Temporary Defect List is replaced with Temporary Disc Management Area. Is recorded.

JP 2004-272268 A WO2004-102542

ECMA-377 http://www.ecma-international.org/publications/files/ECMA-ST/ECMA-377.pdf

  However, if the disk surface is scratched or soiled with respect to substantially the same volume on which page data is multiplexed and recorded, the data of the scratched or soiled volume is lost. Even with such an error correction code between pages, there is a problem that the reliability of data is lowered. Furthermore, there is a problem that it is necessary to keep the data recording efficiency high while ensuring the reliability of the data.

  Accordingly, an object of the present invention is to ensure data reliability and to keep data recording efficiency high.

  As an example, the above-mentioned problem is that user data is added with an error correction code between volumes in which data is recorded, and management information is recorded at least twice in the same volume in different volumes. Solved.

  According to the present invention, data reliability can be ensured and data recording efficiency can be kept high.

A flow chart showing a method of recording on a holographic recording medium. Explanatory drawing which shows the recording method to a holographic recording medium. FIG. 4 is a simulation diagram of a medium showing a recording method on a holographic recording medium. A flow chart showing a method of recording on a holographic recording medium. A flow chart showing a method of recording on a holographic recording medium. Explanatory drawing which shows the recording method of the management information to a holographic recording medium. A flow chart showing a method of recording on a holographic recording medium. Explanatory drawing which shows the recording method of the user data to a holographic recording medium. The block diagram of a holographic recording / reproducing apparatus.

  Hereinafter, a first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a flowchart showing a recording method on a holographic recording medium according to this embodiment.

  In the present embodiment, the signal light beam is condensed on the holographic recording medium by the lens, and simultaneously, the hologram is recorded by irradiating and collimating the reference light of the parallel light beam, and the incident angle of the reference light to the holographic recording medium An example of an angle multiplexing method in which different page data is displayed on the spatial light modulator while performing multiple recording by changing the above will be described. A data group in which page data is angle-multiplexed and recorded in the volume is referred to as book data or a book. The volume refers to a partitioned area on the recording medium, and there are a plurality of volumes on the holographic recording medium.

  When the processing of the recording method according to this embodiment is started (100), it is determined whether the data to be recorded is management information or user data (101). Here, the management information includes information related to user data updated by replacement processing or the like, for example, information indicating an address of an area in which defective user data is recorded.

  If it is determined that the data to be recorded is user data, an amount of data corresponding to n books is collected (102). Thereafter, inter-book parity is generated for n books, and the generated inter-book parity is configured as a parity book having a configuration of m book data. Then, a parity book is added to n books (103). On the other hand, if it is determined that the information is management information, the processes 102 and 103 are not performed.

  In this way, after the data and parity are collected in book units, a plurality of page data included in the book is collected for each book, and parity between page data is generated (104). Then, parity between the generated page data is added to each book data (104). Next, parity generation is performed within each page, and the generated parity is added to each page (105). After generation of each parity in this way, if it is user data (106-user data), normal recording is performed (107), and if it is management information (106-management information), for example, the same data is one Data of the same management information is recorded in two locations at a distance from each other so as not to be simultaneously destroyed by a flaw (108). If the recording is not finished (109-No), the processing is repeated from 101. If it is 109-Yes, the process ends.

  Next, an example of a recording method on the holographic recording medium in the present embodiment will be described with reference to FIG. FIG. 2 is a schematic diagram showing an arrangement of volumes in which book data in which page data is recorded by angle multiplexing is recorded. Each circle indicates a volume in which book data is recorded. In the case of a disk-shaped holographic recording medium, the explanation is about the case where these volumes are arranged in a spiral shape or on the circumference from the inner circumference side. To do.

  In this embodiment, the holographic recording medium is divided into a management area 200, which is an area where management information is recorded, and a user data area 201, which is an area where user data is recorded. The DM0 book data in which the management information is recorded is recorded in the volume 202, and is not recorded in the adjacent volume, but a copy of the book data in DM0 is recorded in the volume (203) separated by a predetermined distance. Is done. This can reduce the possibility of data loss due to a single scratch or defect.

  On the other hand, D0, D1, D2, D3 and four book data are collected in the user data area. Parity is generated for these, and book data P0 (205) composed of parity is generated to constitute an ECC (Error Correction Code) unit (hereinafter referred to as an interbook ECC unit) between books. Then, they are recorded on the volume.

  It should be noted that the parity correction capability between the books should be such that it is possible to substantially correct a scratch or defect of a size that is intended to avoid losing data due to a single scratch or defect in the management area. Thereby, the reliability of user data and the reliability of the data of management information can be made substantially equivalent.

  In addition, by making the distance between data multiplexed in the management area equal to or greater than the parity correction capability for user data, the reliability of management information can be made particularly high. Even if three or more pieces of the same management information are multiplex-recorded, the reliability of the management area can be made particularly high.

  As described above, according to the present embodiment, for user data, a plurality of books are collected to generate inter-book parity, and a book composed of the generated parity is formed, and the parity book is added to the collected books. Thus, it is possible to ensure the reliability of user data against scratches on the holographic recording medium. In addition, by generating a code so that it can be corrected for scratches with a distance equivalent to the distance of multiple recording in the management area, the data code can be compared with multiple recording of user data on separate volumes. Efficiency can be kept high.

  On the other hand, for management information with a relatively small data capacity and high update frequency, the same management information data is recorded in a remote volume without collecting books and building correction blocks. By doing so, it is possible to update without collecting a large amount of book data each time management information is updated, and it is possible to perform additional writing in a small unit even with a write-once medium, so that the recording efficiency can be improved. In addition, since a plurality of the same management information is recorded at a predetermined distance, it is possible to improve data reliability.

  In this embodiment, all the data in the management area is recorded without adding the parity between books. However, the data in the management area is divided from the viewpoint of the update frequency, and the data with low update frequency is recorded. The processing may be divided so that multiple recording is performed without adding inter-book parity for those frequently updated, and adding inter-book parity. Thereby, the recording capacity can be used more effectively.

  In addition, since a book is composed of parity data to be added, the start and end points of recording can be selected by the length of the book unit by virtually adding 0 data even when the start and end of recording does not reach the interbook ECC unit. can do.

  Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 3 shows a holographic recording medium on which recording and reproduction are performed according to this embodiment. In FIG. 3, a circle indicates a volume in which book data in which page data is recorded by angle multiplexing is recorded. Reference numerals 301, 302, 303, 304, 305, and 306 denote tracks on which volumes on which book data is recorded are arranged. Of each track, 301 is a management area, and 302, 303, 304, 305, and 306 are user data areas. In this figure, the track is represented by a square for convenience of drawing, but if it is formed in a spiral shape or a circular shape, it is possible to easily align the book data when recording the book data.

  In the management area 301, a data book DM0 in which data of management information is recorded is recorded in a volume number 1 in FIG. 3, and a copy of DM0 is recorded in a volume number 5 and separated by a predetermined distance. A copy of the book data is recorded.

  On the other hand, one interbook ECC unit is recorded on the track 302 in the user data area.

  In the present embodiment, the book data D0, D1, D2, and D3 are written in the volumes of numbers 17, 19, 21, and 23, and subsequently the parity book data P0 and P1 generated from D0, D1, D2, and D3 are stored. Write to 25 and 27 volumes respectively.

  Unlike the first embodiment, by recording the interbook ECC unit for one skipped volume (skip the volume one by one), the tolerance to defects and scratches can be improved.

  A recording apparatus that records information on a holographic recording medium may use a so-called stop-and-go method in which movement, alignment, stillness, and book data recording are repeated. When this method is used, it is easier to record on the recording medium than on a bit-by-bit recording medium such as a DVD. Therefore, when recording the interbook ECC unit by skipping one by one (skip the volume), it is possible to reduce the interleave RAM required for the encoding system.

  In addition, since the parity book data is two, P0 and P1, it is possible to reproduce even if the parity data book is lost due to one flaw.

  In other words, an inter-book ECC unit is configured with book data skipping a predetermined volume, and an ECC code is selected so that an appropriate correction capability can be ensured, thereby improving the flaw defect tolerance of user data and reducing the update unit. Management information can be handled easily.

  In this embodiment, the case where two parity book data P0 and P1 are generated has been described. However, the present invention is not limited to this, and may be one according to the degree to be corrected. It may be more than one.

  Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 4 is a flowchart showing a recording method for the holographic recording medium shown in FIG. 3 according to the present embodiment, and will be described with reference to FIG.

  Parity book data P00 and P01 are generated from D0, 1, 2, and 3 (401), D0 is recorded in the number 17 volume (402), D1 is recorded in the number 19 volume (403), and D2 is number 21 Record in volume (404), record D3 in volume No. 23 (405), record P00 in volume No. 25 (407), and record P10 in volume No. 27.

  A case where recording of another interbook ECC unit is continued from this state will be described below. First, parity book data P01 and P11 are generated from the following data D4, 5, 6 and 7 (408), D4 is recorded in the number 18 volume (409), and D5 is recorded in the number 20 volume (410), D6. Is recorded in the volume number 22 (411), D7 is recorded in the volume number 24 (412), P01 is recorded in the volume number 26 (413), and P11 is recorded in the volume number 28 (414). In association with these recording processes, the management information update is recorded in the volumes numbered 1 and 5.

  As described above, according to the present embodiment, even if recording is advanced while skipping a predetermined volume, it is difficult for a useless area to exist by recording another book data on the skipped volume. As a result, the reliability of data can be improved and the recording efficiency can be improved.

  Next, a fourth embodiment of the present invention will be described with reference to FIG. FIG. 5 is a flowchart showing an example of a recording method for the holographic recording medium shown in FIG.

  In the present embodiment, it is shown how processing is performed when the recording end portion is less than the interbook ECC unit.

  Reference numerals 501 to 507 are the same as 401 to 407 in FIG. A case will be described in which two book data of D4 and 5 are recorded and terminated after the processing of 507. First, it is assumed that the book data of D6 and D7 are all 0 (dummy data). Then, book data of P01 and P11 are generated from D4, 5 and virtual D6, 7 (508). D4 is recorded in the number 18 volume (509), D5 is recorded in the number 20 volume (510), P01 is recorded in the number 22 volume (511), and P11 is recorded in the number 24 volume (512).

  Then, the management information related to the recording, such as information indicating that the recording is performed with less than the unit length of the interbook ECC unit in relation to these recording processes, is multiplexed and recorded in the two volumes numbered 1 and 5 (513) ). Then, the recording is finished (514).

  As described above, according to the present embodiment, recording can be ended and started in units of books without being constrained in units of interbook ECC units. Therefore, even a write-once medium is sufficiently resistant to defects and scratches. It is easy to select the code length of the interbook ECC unit.

  Next, a fifth embodiment of the present invention will be described with reference to FIG. As shown in the fourth embodiment, since the interbook ECC unit does not always have a fixed length, the beginning and end number volumes of the interbook ECC unit are recorded as information related to recording in book units. Need to be done. This embodiment relates to this method.

  FIG. 6 shows an example of a method for recording management information on a holographic recording medium. Reference numeral 601 denotes an example of a data structure of management information representing replacement processing. status indicates the type of replacement process, such as a pair that represents a defective replacement source and a replacement destination, or a defective replacement source that is specified but a replacement destination is not specified. Defect Address is a replacement The original address is shown, and Replacement Address is the replacement address. Here, there is a problem of which unit is preferable to perform the replacement process.

  In a holographic recording medium, a fixing process (post-cure) may be required for the recorded data. Here, the fixing process (post-cure) is a process of irradiating a predetermined light beam in order to make it impossible to make additional recording after recording information at a desired position in the holographic recording medium. . Fixing processing (post-cure) must be performed at least in units of angle-multiplexed books, and a book is a data group in which page data is angle-multiplexed over a large number, and compared to a Blu-ray cluster, etc. Since this is a large unit, replacement processing is performed in units of books, which is the minimum unit of postcure. This state is shown in FIG.

  Reference numeral 602 denotes a format for listing all the volume numbers of the parity book of the interbook ECC. Reference numeral 603 denotes the start address of the interbook ECC unit, and reference numeral 604 denotes the end address of the interbook ECC unit.

  By registering data in these formats together in the management area every time recording is completed, the case where recording is performed with less than the unit length of the interbook ECC unit as in the case of the fourth embodiment, etc. Can also be supported.

  Further, by aligning the list format related to the replacement process and the list format of the ECC position, that is, expressing the position related to the replacement process and the position related to the ECC in book units, it corresponds to the quality check result by the verification check after recording. Since it is possible to combine the alternation processing mainly for the above and the interbook ECC mainly for dealing with scratches at the time of storage thereafter, it is possible to maintain the data quality.

  Moreover, when the number of scratches increases and the data quality of the interbook ECC becomes insufficient, the replacement process can be added again.

  Next, a sixth embodiment of the present invention will be described. FIG. 7 is a flowchart showing an example of a recording method for the holographic recording medium shown in FIG. 3, and once recording is performed up to book data D5 in the process shown by the flowchart in FIG. Later, we will show how to make additional notes.

  In the present embodiment, an example in which data of D6 and D7 are additionally recorded on the holographic recording medium in a state where the recording shown in FIG.

  First, the book data of D4 is read from the volume of number 18 (701). Next, the book data of D5 is read from the volume of number 20 (702). Parity book data P01 and P11 are regenerated from the read D4 and D5 book data and the newly entered D6 and D7 book data for additional writing (703). Next, D6 is recorded in the number 26 volume (704), and D7 is recorded in the number 28 volume (705).

  Next, P01 regenerated in 703 is recorded in the volume number 30 (706). Similarly, P11 regenerated in 703 is recorded in the volume number 32 (708). Then, in relation to these recording processes, management information related to recording such as information for invalidating P01 and P11 before additional recording recorded in number 22 and number 24 together with the start address and final address of the new interbook ECC unit. Updates are recorded in two volumes numbered 2 and 6 according to the format shown in FIG. 6 (709).

  As described above, according to the present embodiment, when the recording is performed after the recording is finished in the book unit which is less than the interbook ECC unit unit, the recording can be performed again in the interbook ECC unit unit even in the write-once medium. Therefore, the additionally recorded medium can efficiently perform ECC processing in units of inter ECC blocks, and can keep the reproduction speed high.

  Further, according to this embodiment, when data recorded in units of inter ECC blocks or less continues, for example, a, b, and c, the ECC processing must be performed by combining the virtual data for each of a, b, and c. By having to do so, it is possible to reduce the possibility that the playback processing will become heavy and the playback speed will be slow.

  Further, by recording information for invalidating the parity book data before additional recording in the management information, the parity book data before additional recording is not erroneously reproduced. Here, as information to be invalidated, for example, parity book data before additional writing may be handled as defective, and replacement processing information indicating the address of the data may be recorded in the management information.

  Next, an example of each arrangement of ECC in each embodiment will be described. FIG. 8 is a schematic diagram showing the arrangement of each ECC when a plurality of books are collected and ECC is added in angle multiplexing holographic recording. Here, the intra page ECC indicates an ECC within a page, the inter page ECC indicates an ECC between pages, and the inter book ECC indicates an ECC between books.

  A method for constructing an interbook ECC by adding a parity book will be described with reference to FIG. 8 together with the relationship between the interpage ECC and the intrapage ECC.

  Reference numeral 803 denotes an interbook ECC. Collect multiple books and collect data with the same relationship on the same page as shown in the figure (for example, data multiplexed by the same reference beam angle or data with the same header information indicating the number of pages each page data has) Thus, a plurality of ECC blocks are formed (each two-dot broken line indicates one ECC block), and Parity is added to the data. The added parity is added to the same page of the parity book to form a parity book.

  Next, the interpage ECC indicated by 802 is added to the data. The interpage ECC collects approximately the same number of data from each page to form a plurality of ECC blocks (each dashed line is one ECC block), and adds parity to each ECC block.

  Reference numeral 801 denotes addition of an intra page ECC. In 801, a certain number of data in the page are collected and divided into a plurality of ECC blocks (each battle indicates one ECC block), and the ECC is added to the data.

  Heretofore, the addition of ECC has been described. As for the type of each ECC code, in order to increase the recording density of data recorded on the holographic recording medium, the correction capability is high, but the probability of erroneous correction is assumed from a relatively good quality LDPC (Low Density Parity-check code) is used as intra-page ECC, Reed-Solomon code is used for inter-page ECC in order to compensate for the characteristics of LDPC that exists in a situation where the probability of error correction is relatively good. It is effective to use a Reed-Solomon code in consideration of burstiness. However, the present invention is not limited to this.

  Also, here, an example has been shown in which an ECC block is generated by collecting data of the same positional relationship within each book and the same page in the interbook ECC, but this is a case where the configuration method is the simplest. . Processing is complicated by combining different pages in each book and data with different positional relationships. However, if there is a problem with recording at a specific angle in angle multiplex recording, or reading out due to a defect in a CCD that is a kind of reading device. It is possible to increase error resistance against a case where a specific dot sometimes causes an error.

  Further, the same type of correction code is used for the interbook ECC and the interpage ECC, the code length is made common, the number of ECC blocks divided by each is substantially the same, and the generation of the interbook ECC and the generation of the interpage ECC are performed simultaneously. However, if the system is not a sequential system, the necessary interleaving memory can be integrated into one, which is effective in simplifying the system.

  Next, an example of the holographic recording / reproducing apparatus of each embodiment will be described with reference to FIG. FIG. 9 is a diagram showing a holographic recording / reproducing apparatus according to an embodiment of the present invention. In FIG. 9, 900 is a holographic recording medium, 901 is a disk motor that rotates the holographic recording medium, 902 is an optical pickup that emits signal light from the recording signal, and 903 is emitted from 902 This is a phase conjugate optical system that generates phase conjugate light of reference light by the phase conjugate optical system 12. Here, the phase conjugate light is a light wave that travels in the opposite direction while maintaining the same wavefront as the input light.

  Reference numeral 904 denotes a disc cure optical system for irradiating fixing light to recorded book data. Reference numeral 905 denotes an access control circuit for moving each optical system of 902, 903, and 904 to a target location. Is a light source driving circuit for driving the laser of the optical pickup 902 and the disk cure optical system 904.

  A servo control circuit 907 performs rotation control of the disk motor 901, position control of the optical pickup 902, focus control, and the like, and 908 changes the light beam system of the disk cure optical system 904 between continuous recording and recording stop / start. Thus, the light beam diameter control circuit is used to speed up the fixing process by taking a large light beam system only during continuous recording.

  Reference numeral 909 denotes an interface circuit that exchanges recording data or reproduction data with an external device. Reference numeral 910 denotes a signal generation circuit that performs ECC addition, modulation processing, and the like. This is a signal generation circuit for performing the generation process.

  The signal generation circuit 910 includes an intra-page correction code generation circuit 911, an inter-page correction code generation circuit 912, an inter-book correction code generation circuit 913, and a generation processing buffer RAM 914. The input user data is temporarily stored in the reproduction processing buffer RAM 914. The data stored in the generation processing buffer RAM 914 is read out and subjected to each correction code addition process described below. The intra-page correction code generation circuit 911 and the inter-page correction code generation circuit 912 perform correction code generation processing for all books.

  On the other hand, the inter-book correction code generation circuit 913 performs a generation process on the user data input in the user data recording area, and does not perform a generation process on the management information. After the correction code is added by the intra-page correction code generation circuit 911 and the inter-page correction code generation circuit 912, the same data is copied according to the control of the multiprocessing circuit 930, and the management information data is data for two books. The access control circuit 905 controls the position of data to be overwritten, and the same book data is recorded in two different volumes on the management area.

  On the other hand, reference numeral 920 denotes a signal reproduction processing circuit that performs demodulation processing, error correction processing, and the like, and performs error correction by reproducing the data that has been written as described in the above-described embodiment during reproduction. The signal reproduction processing circuit 920 includes an in-page correction processing circuit 921, an interpage correction processing circuit 922, an interbook correction processing circuit 923, and a reproduction processing buffer RAM 924. Data reproduced from the optical pickup is temporarily stored in the reproduction processing buffer RAM. The data stored in the reproduction processing buffer RAM 924 is read out and subjected to each correction process described below. The intra-page correction processing circuit 921 and the inter-page correction processing circuit 922 perform correction processing in reproduction of all books.

  On the other hand, in the inter-book correction process, the correction process is performed on the user data in the user data area, but the correction process is not performed on the management information. The management information data is corrected by the in-page correction processing circuit 921 and the inter-page correction processing circuit 922, and the multiple-written data is managed in cooperation with the access control circuit 905 under the control of the multi-processing circuit 930. Read from two different volumes on the region. If the two pieces of read management information are not correctable, it is determined whether or not they match, and if they match, the management information is read with the matched contents. Thereby, the certainty of reading of management information can be improved. If one of the management information is uncorrectable and data cannot be read, the non-correctable information is read. Thereby, readability can be raised.

  As mentioned above, according to this, the circuit which implement | achieves each above-mentioned Example can be provided.

  Of course, the above embodiments may be appropriately combined.

  Further, every time the management information is updated in the above embodiment, the same management information is recorded twice on the holographic recording medium. Until the data amount of the management information satisfies the book unit, for example, in the holographic recording / reproducing apparatus. Management information is stored in the memory (for example, the generation processing buffer RAM 914), the management information is updated, and when the data amount of the management information satisfies the book unit, the same management information is stored in the holographic recording medium. You may record twice. This can further increase the recording efficiency. Further, the same effect can be obtained by attaching the memory to the recording medium and holding the memory until the data amount of the management information satisfies the book unit.

  Moreover, in the said Example, although the case where two or more same management information was recorded was shown about management information, the same thing said in the said Example does not necessarily need that all information is the same, management information Among them, particularly important information such as defect management information may be recorded at least twice.

103 Inter-book parity code generation 104 Inter-page parity code generation 105 In-page parity code generation 108 Data multiplex recording 900 Holographic recording medium 901 Disc motor 902 Optical pickup 903 Phase conjugate optical system 904 Disc cure optical system 905 Access control circuit 906 Light source drive Circuit 907 Servo control circuit 908 Beam diameter control circuit 909 Interface circuit 910 Signal generation circuit 911 In-page correction code generation circuit 912 Inter-page correction code generation circuit 913 Inter-book correction code generation circuit 914 Generation processing buffer RAM
920 signal reproduction processing circuit 921 intra-page correction processing circuit 922 inter-page correction processing circuit 923 inter-book correction processing circuit 924 reproduction processing buffer RAM
930 Multiple processing circuit

Claims (12)

A recording method for recording information on a holographic recording medium,
When trying to record data in multiple volumes on a holographic recording medium,
When the data to be recorded is user data, an error correction code is generated between the plurality of volumes,
Adding an error correction code between the generated volumes to the user data;
A recording method, wherein when the data to be recorded is management information, the same management information is recorded in different volumes. The recording method according to claim 1,
The recording method is an angle multiplexing method in which a plurality of pages are multiplexed and a book is generated by changing the incident angle of the reference light,
If the data to be recorded is user data, generate an error correction code between books,
An error correction code between the generated books is added to the user data. The recording method according to claim 2,
A process of generating an error correction code within the page of the generated book;
A process of adding an error correction code in the generated page;
A process of generating an error correction code between pages of the generated book;
A process of adding an error correction code between the generated pages;
A recording method characterized by comprising: The recording method according to claim 2,
A recording method characterized in that parity by error correction code between books added to user data is recorded in a volume on a holographic recording medium as an independent book. The recording method according to claim 2,
When recording a data group that is less than an interbook ECC unit, a fixed data is virtually inserted, and then an error correction code between books is generated for the data group and the fixed data. . The recording method according to claim 5, wherein
A recording method, wherein information indicating an address of a first book of an interbook ECC unit and information indicating an address of a final book are recorded as management information. The recording method according to claim 5, wherein
When adding data after generating an error correction code between books for the data group and the fixed data, the data group is reproduced, and the reproduced data group and the newly added data are added between the books. A recording method comprising generating an error correction code. The recording method according to claim 7, wherein
A recording method, wherein information indicating that parity by an error correction code between books for the generated data group and the fixed data is invalid is recorded in management information. The recording method according to claim 2,
When recording the management information, the same management information is recorded in a separate volume. The recording method according to claim 6, wherein
For a book with poor recording, replace it with another book and perform replacement processing to record replacement information in the management area.
A recording method comprising: recording the information indicating the address and the replacement information of the replacement process in the same format. User data to which an error correction code across books, an error correction code between pages in the same book, and an error correction code within a page are added, and a plurality of identical management information are recorded by the angle multiplexing method. A reproduction method for reproducing data from a holographic recording medium,
Playing back the data that has been subjected to the error correction process in the page and the error correction process between pages in the book,
If the reproduced data is user data, perform error correction between books,
If the reproduced data is management information, the management information is reproduced from the reproduced data. A recording device for recording information on a holographic recording medium,
Recording processing means for recording a plurality of pages in the same volume or substantially the same volume, and generating a book;
A first correction processing circuit for generating an error correction code in the page;
A second correction code generation circuit for generating an error correction code between pages in the book;
A third correction code generation circuit for generating an error correction code between books for user data;
A recording apparatus comprising: multiple recording processing means for recording the same management information in different books for management information.

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