JP4445942B2 - Information recording / reproducing method and information recording / reproducing apparatus - Google Patents

Description

  The present invention relates to an information recording medium for recording and reproducing information using light, an information recording / reproducing method, and an information recording / reproducing apparatus.

  A technique for recording and reproducing information using light is widely used in the world. A typical example is an optical disk. Optical disks are characterized by the fact that a semiconductor laser can be used as a light source, the recording medium can be removed from the recording / reproducing apparatus, and the cost per bit of the recording medium is low. In addition, holographic recording has been actively researched in recent years. In addition to the low bit unit price, forgery is difficult, and expectations for future software distribution media are increasing. Therefore, in these information recording media, it is desirable to increase the recording capacity without losing this characteristic and taking advantage of the characteristics of light transmission and transmission. In view of this, studies have been made on increasing the capacity by laminating a plurality of recording layers on both the optical disk and the planar hologram and making the recording area three-dimensional. However, with three or more layers, the transmittance and recording sensitivity of each layer are in a trade-off relationship, and either the reproduction signal quality or the recording sensitivity must be sacrificed.

  Therefore, a technique for eliminating this trade-off has been developed. For example, in Japanese Patent Application Laid-Open No. 2003-346378, a recording layer using an electrochromic material is multilayered, and the recording layer is sandwiched between a pair of electrodes. And recording the information by selectively coloring the recording layer so as to absorb light by changing the absorption spectrum by applying a voltage to the recording layer itself.

As an example of a hologram, JP-A-11-345419 describes a read-only multiple hologram information recording medium in which single mode planar optical waveguides are stacked in multiple layers. An information recording medium provided with a periodic scattering factor having a period substantially equal to the period of the waveguide mode of this single mode planar optical waveguide is guided by the periodic scattering factor when guided light is introduced into an arbitrary optical waveguide. A feature is that a hologram is formed by diffracted light diffracted out of the waveguide. It is described that this planar optical waveguide hologram card is also a business card size, which is a laminate of 100 planar optical waveguides and has a storage capacity of approximately 130 GB.
JP 2003-346378 A JP-A-11-345419

  In order to record and reproduce information using light on an information recording medium whose effective recording density is improved by multilayering, it is necessary to select a layer. If the layer selection is not successful, there is no defect in the recording material, and the information There is a problem that information cannot be recorded or reproduced even if it is stored normally. In the case of a planar optical waveguide hologram card, it is necessary to make light incident on a desired optical waveguide among a plurality of optical waveguides provided on the information recording medium. In a layer-selective optical disc by voltage, it is necessary to apply a voltage to an electrode for a desired recording layer among a plurality of electrodes.

  One of the features of recording and reproducing information using light is that the recording medium (disc) can be removed from the recording / reproducing apparatus. However, the recording medium can be dropped while being carried, stress can be applied to the recording medium. There is a possibility of being scratched. For example, in a planar optical waveguide hologram card, if a phenomenon occurs such that the light incident surface is scratched or the medium warps, light cannot be incident on a desired layer, or light scattered by the scratches can be divided into a plurality of optical waveguides. May cause the necessary information not to be reproduced. In a layer-selective optical disc by voltage, the layer may not be selected even when a voltage is applied due to the destruction of the electrode portion or the poor contact with the recording layer, and necessary information may not be reproduced.

  An object of the present invention is to solve these problems and provide a large-capacity information recording medium, an information recording / reproducing method, and an information recording / reproducing apparatus that can be handled easily without causing the user to feel inconvenience. is there.

  An information recording medium according to the present invention has a plurality of recording layers formed by stacking, each recording layer is divided into a plurality of recording areas, and the recording area corresponding to each recording layer is a recording layer. The recording areas are arranged so as to overlap each other in the stacking direction, and each recording area can be selected independently, and only the selected recording area can be recorded or reproduced.

  Information recording on the information recording medium of the present invention is performed by selecting a plurality of recording areas belonging to different recording layers and not overlapping in the depth of focus direction, from a plurality of recording layers within the focal depth of the recording light. Is performed by distributing and recording the write information for forming a plurality of selected recording areas. The write information forming the logical group includes a plurality of data blocks obtained by dividing user data and parity data generated from the plurality of divided data blocks.

  An apparatus for recording information on an information recording medium according to the present invention divides write information forming a logical group into a plurality of data blocks and generates parity data from the divided data blocks. From the data processing unit and a plurality of recording layers within the focal depth of the recording light, select a number of recording areas equal to or greater than the number of the data blocks so that they belong to different recording layers and do not overlap in the depth of focus direction And a recording processing unit that performs a recording operation in a one-to-one correspondence with a plurality of recording regions that respectively select the plurality of data blocks and parity data. Embedded information is distributed and recorded in a plurality of selected recording areas.

  According to the present invention, information is three-dimensionally distributed and stored in an information recording medium without greatly changing the conventional recording / reproducing apparatus, and even when a certain recording area cannot be selected due to an unexpected event, It is possible to restore the information of the recording area that can no longer be selected from the information stored in a distributed manner. That is, an inexpensive and highly reliable large-capacity information recording medium and recording / reproducing apparatus can be provided.

  A multilayer recording medium is used for the recording / reproducing apparatus and recording / reproducing method of the present invention. As the multilayer recording medium, a voltage layer selective multilayer recording medium may be used, or a planar optical waveguide hologram medium may be used.

  When a voltage layer selective multilayer recording medium is used, the basic state of each recording layer is transparent. Only the layer to which voltage is applied between the electrode layers sandwiching the recording layer is colored. In the present invention, the direction of voltage when coloring is defined as positive. If the recording function is lost by irradiating the recording laser beam and the recording mark is formed, the recording mark cannot be seen when the entire layer is returned to the transparent state, and does not hinder the recording / reproduction of other layers. Thereby, since there is no interference of other layers, the layer interval can be narrowed, and the multilayer and the capacity can be increased as compared with the conventional multi-layer disc.

  FIG. 1 is a schematic cross-sectional view showing a configuration example of a voltage layer selective multilayer recording medium. Here, for ease of understanding, the light is shown as incident from the lower side of the drawing. From the light incident side, the medium is the substrate 1, the protective layer 2, the first electrode (transparent electrode) 3, the electrochromic material layer 4, the second electrode 5, the insulator layer 6, the UV curable resin layer 7, and the protective substrate. 8 is comprised, 9 is equivalent to a groove part and 10 is equivalent to a land part. A combination of a first electrode (transparent electrode) 3 and an electrochromic material layer 4 is laminated in multiple layers with an insulator layer 6 therebetween. Another layer such as a thin insulator layer or an interface layer may be interposed between the recording layer (electrochromic material layer) and the first electrode or the second electrode.

  In the medium configuration of FIG. 1, in addition to the electrochromic material layer that directly develops color when a voltage is applied, a layer having a region that emits light when a voltage is applied and a region that develops or decolors when receiving the light can also be used as the recording layer. That is, as the recording layer, a laminated film of an organic or inorganic electrochromic material layer and a solid electrolyte layer, a mixed material layer or a laminated film of an electroluminescent material and a photochromic material can be used. Thereby, only an arbitrary recording layer can absorb light, and other recording layers can hardly absorb light. Examples of electrochromic materials include polymers of tungsten oxide and thiophene-based organic molecules. In addition, they are described in “Electrochromic Display” published on June 28, 1991 by Sangyo Tosho Co., Ltd. Many known electrochromic materials can be used, such as various materials.

  Photochromic is a phenomenon in which the absorption spectrum of crystals, molecules or complexes changes reversibly by light irradiation. Diarylethene-based materials known as typical photochromic materials usually have a wavelength region of 450 nm or less. Absorption occurs in the vicinity of 500 to 600 nm. Diarylethene-based materials are described in, for example, Japanese Applied Physics, vol. 35, 3987 (1993). In addition, fluoric compounds that become colored by UV irradiation and become absorbed at a specific wavelength are reported in the Ricoh Technical Report [http://www.ricoh.co.jp/about/business_overview/report/ 29 / pdf / B2906.pdf].

  Next, a configuration when using a multilayer planar optical waveguide hologram medium will be described. Multi-layer planar optical waveguide hologram media are optical waveguide hologram media ("Electronic Communication Society Journal" '77 / 4 Vol.J60-C, No.4, pp.197-204 (52-185 [c-34 ])) Is laminated to obtain a multiple recording hologram medium. FIG. 2 shows a structural example of a hologram memory according to an embodiment of the present invention. The hologram memory has a structure in which a clad layer 12a, a core layer 12b, a clad layer 13a, a core layer 13b, a clad layer 14a, and a core layer 14b are sequentially laminated on the substrate 11 from below, and the clad layer 15 is formed on the uppermost layer. have. In each core layer, a scattering factor, that is, a hologram having a period substantially equal to the period of the waveguide mode of the optical waveguide is formed. The scattering factor modulates the refractive index of the core layer, thereby superimposing information in advance.

  With this configuration, the reproduction illumination light 17 is introduced from the reproduction illumination light source 16 into an arbitrary core layer, that is, the core layer 12b in FIG. The reproduction illumination light 17 propagates as sheet-like guided light in the in-plane direction of the core layer, is scattered by the hologram, and is emitted as diffracted light 18 from the surface of the hologram memory. A hologram image 19 is formed on the image plane by the diffracted light 18. Information can be read by capturing the hologram image 19 with a two-dimensional photodetector such as a CCD. In this way, by directly detecting the hologram image 19 with the two-dimensional photodetector, a special lens group for reading information becomes unnecessary.

  An example of the configuration when an optical layer selection type planar optical waveguide type multilayer photochromic medium is used is shown below. Similar to the layer selection type optical disc, the basic state of each recording layer is transparent. The recording layer of the light-selective planar optical waveguide multilayer photochromic medium corresponds to the core layer of the planar optical waveguide hologram medium, and has a structure in which both sides thereof are sandwiched by clad layers having different refractive indexes. The layer is selected by allowing reproduction illumination light to enter an arbitrary optical waveguide, thereby coloring only the recording layer of the arbitrary core layer. The photochromic material returns to a basic state, that is, a transparent state when light incident on the optical waveguide is stopped. If the recording layer is formed by irradiating another selected recording laser beam to the selected layer and losing the coloring function of the colored photochromic material, the recording mark will be Is not visible, and does not interfere with recording / playback of other layers.

  Regardless of which multilayer recording medium is used, the multilayer recording medium is designed to have a plurality of recording areas in a single layer, and a plurality of recording media selected so as not to overlap in the direction of the focal depth of light. Write information (data) forming a logical group is three-dimensionally distributed and stored in a plurality of recording areas of the layer. Due to this feature, even when a specific recording area cannot be selected due to an unforeseen event without making major changes to the conventional recording / playback device, it is possible to select from information stored in a distributed manner in the remaining recording areas. It becomes possible to restore the information of the recording area that has become impossible.

  As a method for restoring original information from information stored in a distributed manner, an error correction code using parity that is put into practical use in a disk array device can be used. A disk array is a device that accesses a plurality of small disk devices arranged in parallel as an external storage device of a computer system, records data in a distributed manner, and accesses them in parallel. Such a disk array device is characterized in that data writing and data reading are performed at high speed by operating a plurality of built-in disk units in parallel. In addition, reliability is improved by providing redundancy. This RAID is classified into various levels, and representative examples thereof include RAID 4 (level 4) and RAID 5 (level 5). D.Patterson, G.Gibson, and RHKartz; A Case for Redundant Arrays of Inexpensive Disks (RAID), in ACM SIGMOD Conference, Chicago, IL, (June 1988) The performance and reliability of the disk array (level 5) that distributes the array (level 3) and data and handles them independently have been reported.

  In the present invention, high reliability is realized by arranging a plurality of recording areas in one multilayer information medium, instead of arranging a plurality of small disk devices. In addition, by creating multiple recording areas that can be selected independently within the depth of focus, and providing conditions for selecting the recording areas so that they do not overlap in the depth of focus direction, the layers can be different with only one recording / reproducing head It becomes possible to access the recording areas of a plurality of recording layers without being aware of the above. In RAID, what is constituted by a plurality of heads and a plurality of disks can be realized by a simple configuration of one head and one multilayer information recording medium in the present invention.

  Here, an error correction method with reference to RAID 4 will be described. Input data is divided into data blocks in units of one sector (or in units of several sectors), and each divided data block is distributed and stored in a plurality of recording areas. Also, parity data is generated from the divided data blocks, and the generated parity data is stored in a specific recording area.

  On the other hand, RAID 5 also stores the divided data blocks in a plurality of recording areas in the same manner as RAID 4. Nevertheless, unlike RAID 4, RAID 5 does not create a parity-only recording area, but stores parity data in each recording area as appropriate.

  FIG. 3 is a schematic diagram showing an example of an information recording / reproducing apparatus according to the present invention. FIG. 3 is a block diagram showing an example of a system including the multilayer information recording medium 20 to which RAID 4 is applied. Here, consider a case where one recording layer constituting the multilayer recording medium is divided into four recording areas.

  The multilayer information recording medium 20 has one recording layer divided into four recording areas a, b, c and d, and has three recording layers 21, 22 and 23 and a parity storage recording layer 24. The drive includes a controller 25 and a disk I / F 26. The recording layers 21, 22, and 23 store the divided data blocks (stripes). The parity storage recording layer 24 stores parity data (redundant data). When writing data, the controller 25 divides the data sent from the host computer 27 and stores the divided data blocks in different recording layers 21, 22 and 23. At that time, the controller 25 calculates the exclusive OR of each data block to generate parity data, and stores this parity data in the parity storage recording layer 24.

  In addition, when reading data, the controller 25 reads data blocks stored in the recording areas 21, 22, and 23. The controller 25 combines the data blocks and supplies the combined data to the host computer 27. A disk I / F (interface) 26 connects the controller 25 and the multilayer information recording medium 20.

  Even when a failure occurs in any one of the recording layers 21, 22, and 23, the controller 25 can restore the data block by using the parity data stored in the parity storage recording layer 24. For example, consider a case where data A is distributed and stored in the recording areas 21a, 22b, 23c and the parity storage recording area 24d and the recording area 21a fails due to an accident. At this time, the controller 25 calculates the exclusive OR of the data block read from the remaining recording areas 22b and 23c and the parity data read from the parity storage recording area 24d, and restores the data block in the recording area 21a. To do.

  The data should be distributed so that they do not overlap in the direction of the focal depth of light, as in the above example, the data A is distributed and stored in the recording areas 21a, 22b, 23c and the parity storage recording area 24d. By distributing the data to different layers, the physical distance between the recording areas can be increased. In addition, by distributing the data to multiple layers so that they do not overlap within the depth of focus, even if multiple layers are selected, the data that is distributed and arranged in these multiple recording layers exists as if it were a single layer from the drive side Looks like you do. This indicates that it is not necessary to move and adjust the optical element in the depth of focus direction on the drive side, and that the apparatus / system configuration is as simple as the conventional optical disk apparatus.

  On the other hand, when data is distributed and stored so as to overlap in the focal direction as in the recording areas 21a, 22a, and 23a, the overlapping recording areas within the same focal depth appear to be the same recording area on the drive side. Therefore, it is necessary to select the recording areas 21a, 22a, and 23a at different times and to repeatedly perform the recording / reproducing operation. In addition, data is concentrated in a recording area having a close physical distance. For this reason, it is not preferable to distribute and store data in a plurality of layers by a method that overlaps in the focal direction from the viewpoint of data recording / reproducing speed and data safety.

  When data is dispersed in the multilayer planar optical waveguide hologram medium, the data sent from the host computer is divided by the controller, and the hologram image formed in each recording area is calculated from the divided data.

  In the case of RAID 5 in which parity data is appropriately stored in each recording area, an independent recording area is not required for parity storage, and therefore when writing information forming a logical group is divided into a plurality of data blocks. The number of data blocks is preferably the same as the number of recording areas provided in each recording layer.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, embodiment described below is an example, Comprising: This invention is not limited by this. In the drawings described below, components having the same function are denoted by the same reference numerals, and repeated description thereof is omitted.

[Example 1] Layer-selective optical disc-voltage selection As shown in FIG. 4, an in-groove having a diameter of 12 cm, a thickness of 0.6 mm, a track pitch of 0.74 μm, a depth of 60 nm, and a groove width of 0.35 μm. An Ag ₉₄ Pd ₄ Cu ₂ translucent reflective layer 29, an ITO transparent electrode 30, an electrochromic material layer 31, ion passage control is provided on a polycarbonate substrate 28 having a tracking groove for recording and address information as wobble of the groove. The layer 32, the solid electrolyte layer 33, the ITO transparent electrode 34, and then the layers 31 to 34 were repeatedly laminated twice to produce a multilayer recording medium including three recording layers. Finally, an ultraviolet curable resin layer was formed by coating.

In the electrochromic material layer, tungsten oxide WO ₃ was used as a coloring material. A solid electrolyte material is laminated thereon via an ion passage control layer. The electrochromic material layer is formed by sputtering. The electrochromic material layer is colored by applying a voltage between the upper and lower electrodes. Each layer is formed by sputtering or coating, and laser light is incident from above. The wavelength of the laser beam was 660 nm and the track pitch was 0.6 μm.

The layer structure was Li triflate (official name: Li trifluoromethane sulfonate) for the acrylic UV curable resin, and tantalum pentoxide Ta ₂ O ₅ for the solid electrolyte layer. The electrochromic material layer is composed of three layers or two layers. In the case of the three layers, for example, an oxidation coloring type first coloring layer of IrOx or NiOx (x is a positive number less than 1) is 70 nm, a solid electrolyte layer. It consists of _three layers of a Ta ₂ O ₅ layer of 150 nm and a WO ₃ layer of 100 nm as a reduction coloring type second coloring layer. In the case of two layers, for example, an OH ion storage layer of 100 nm of Cr ₂ O ₃ and of WO ₃ The coloring material layer is composed of two layers of 100 nm.

  The merit of using an inorganic material layer is that optical properties (refractive index) are close to those of the transparent electrode ITO, and high-precision film thickness control by sputtering is possible, so that a multilayer information recording medium having high transparency can be produced. It is to become. Further, since all the layers constituting the multilayer information recording medium can be formed by sputtering, it can be produced using an existing optical disc production line.

As a material used for the electrochromic material layer, organic materials such as polythiophene-based organic polymers and thiophene-based organic oligomers and polymers can also be used. The conductive organic material can be formed by coating, and is characterized by excellent coloring efficiency. The polymer of thiophene is formed by vacuum deposition or electrolytic polymerization. In the electropolymerization, poly (3-methylthiophene) which is a thiophene derivative is used as a monomer, LiBF ₄ is used as a supporting electrolyte, and benzonitrile is used as a solvent.

The merit of using an organic material layer is that it has conductivity, conductivity increases with increasing temperature, and can also have photoconductivity, so photocarriers are accelerated by an electric field, and recording sensitivity increases with increasing temperature. In other words, unlike WO ₃ , it is not necessary to enter and exit moisture (protons) in the film for color erasing. Coloring occurs when ions such as Li move to the vicinity of the molecule, so that electrons are given to the molecule and can be excited by light. When the electrochromic material layer is formed by coating, the groove is gradually filled by lamination, and the distance between the electrodes on both sides of the recording layer is closer to the land portion than to the groove portion.

  When a voltage is applied to the transparent electrodes on both sides of the recording layer to be recorded or reproduced, only that layer is colored and absorbs and reflects the laser light. Therefore, when laser light with a wavelength of 660 nm is irradiated, information is selectively displayed. Can be recorded and read.

  As shown in FIG. 5A, each recording layer was formed so as to have three recording areas having the same area. For example, the first recording layer has three recording areas 35a, 35b, and 35c. When each layer is formed by sputtering, a mask is applied to the exposed electrode portion, and the mask is made smaller one by one in accordance with the formation of the upper layer, so that each recording area 36a, 36b, 36c, 37a, 37b is recorded. , 37c was prepared so that the outermost surface was exposed. The surface of each recording area is a transparent electrode 5. The subscript alphabets a, b, and c indicate the positions of the recording areas.

  For example, the recording area 35a of the first recording layer, the recording area 36b of the second recording layer, and the recording area 37c of the third recording layer are overlapped in the focal depth direction of the recording / reproducing laser beam 38. When the recording area of each layer is colored so that it does not become visible, as shown in FIG. 5B, the recording medium looks as if it is a single-layer medium from the device (photodetector). Accordingly, the recording / reproducing operation can be performed without being particularly aware of the fact that the medium is a multilayer medium.

  Each recording layer may be further divided in the radial direction as shown in FIG. When the recording layer is also divided in the radial direction, it is not necessary to apply a voltage to the recording area other than the recording area including the track on which information is recorded / reproduced. No voltage is applied to the material, and the durability of the device is improved even when a material having the same number of repetitions is used.

  Further, a polycarbonate substrate having a diameter of 120 mm and a thickness of 0.6 mm was attached thereon. Light was incident from the side of the laminated substrate. A metal electrode such as W-Ti may be used instead of the transparent electrode farthest from the light incident side.

  A mechanism for supplying voltage from the recording device to the recording medium will be described below. As shown in FIG. 7, the recording medium is set in a disk receiving portion 39 provided in the apparatus. 7A is a perspective view of the recording medium and the disk receiving portion 39, and FIG. 7B is a schematic cross-sectional view of the recording area a when the disk is placed.

  The transparent electrodes formed on the surface of the recording medium are connected by divided concentric electrodes 40a, 40b, and 40c near the center hole of the disk. Since these divided concentric electrodes 40a, 40b, 40c are connected to different electrodes on the disk rotation shaft of the recording / reproducing apparatus, they are located at positions corresponding to the electrodes of the disk provided on the disk receiving portion 39 of the rotation shaft. It is connected to a plurality of pin electrodes 41a, 41b, 41c arranged concentrically with a little springiness in the vertical direction. The concentric arrangement pin electrodes 41a, 41b, and 41c are connected to a power source in the apparatus through the extraction electrode.

  Information was recorded / reproduced on the recording medium. FIG. 8 is a block diagram showing a configuration example of an information recording / reproducing apparatus using a layer selection type multilayer recording medium based on voltage selection according to the present embodiment. The information recording / reproducing operation will be described below with reference to FIG. First, as a motor control method for recording / reproducing, a method employing a ZCAV (Zoned Constant Linear Ve1ocity) method in which the number of rotations of the disk is changed for each zone for recording / reproducing will be described.

  Information from the outside of the recording apparatus is divided into a plurality of data to which parity is given through a controller. At this time, the recording data is divided into three data to which the parity is given by the data processing unit 91 as in the RAID5. As with RAID 4, only the parity may be stored in one recording area. However, if the recording area storing only the parity cannot be selected, the subsequent restoration cannot be performed. Therefore, it is preferable to take one of the following two measures.

  First, the recording area storing only the parity is constructed using an existing rewritable phase change material that does not require layer selection. The recording area using the rewritable phase change material is provided apart from the other recording areas by using a spacer layer or the like in order to reduce the influence of multiple interference with the other recording areas. By recording parity in a layer that does not require layer selection, the risk of data loss can be reduced.

  Second, the parity is copied to another recording area, and the recording area where the parity is copied is changed to a different recording area every certain period. In the existing optical disc Blu-Ray Disc, a file with a small file capacity is recorded in two places in advance by a function called robust attribute so that one of the files can be dealt with when it cannot be read. In the present invention, the recording area where the parity is duplicated is changed to a recording area which is different in time, thereby reducing the probability that the recording area storing two parities will simultaneously fail due to the durability of the recording area. Is possible. If the same thing is done by RAID, HDD replacement work is required. However, in the information recording medium of the present invention, since a large number of recording areas are created in advance, no replacement work is required. It can be completed only by the work in the recording apparatus.

  Each data is transmitted to the 8-16 modulator 87 in units of 8 bits. When information was recorded on the information recording medium 81, recording was performed using a modulation system that converts 8 bits of information into 16 bits, a so-called 8-16 modulation system. In this modulation method, information having a mark length of 3T to 14T corresponding to 8-bit information is recorded on the medium. The 8-16 modulator 87 in the figure performs this modulation. Here, T represents a clock cycle during information recording. The disk was rotated so that the linear velocity of the light spot was 15 m / s.

  The 3T to 14T digital signals converted by the 8-16 modulator 87 are transferred to the recording waveform generation circuit 85 to generate a multi-pulse recording waveform. In the recording waveform generation circuit, signals of 3T to 14T are made to correspond to “0” and “1” alternately in time series. In the recording waveform generation circuit 85, when forming a series of high power pulse trains for forming the mark portion, the first pulse width and the last pulse width of the multi-pulse waveform according to the length of the space portion before and after the mark portion. It has a multi-pulse waveform table corresponding to the method of changing the pulse width of the tail (adaptive recording waveform control), so that the multi-pulse recording waveform that can eliminate the influence of thermal interference between marks as much as possible It has occurred.

  The recording waveform generated by the recording waveform generation circuit 85 is transferred to the laser driving circuit 86, and the laser driving circuit 86 causes the semiconductor laser in the optical head 83 to emit light based on this recording waveform. The optical head 83 is equipped with a semiconductor laser having an optical wavelength of 660 nm as a laser light source for information recording. Further, this laser beam was narrowed down onto the recording layer of the optical disk 81 by an objective lens having a lens NA of 0.65, and information was recorded by irradiating the laser beam. Recording is performed so that the electrochromic action of the film is lost by laser light irradiation, and no color is developed even when a voltage is applied, or the absorption spectrum is different from that before recording. At this time, the recording areas 35a, 36b, and 37c shown in FIG. 5 were colored by the voltage application by the recording area selection unit 92, and information was distributed and recorded in a plurality of layers.

  Since the recording principle is as described above, it is possible to easily form a plurality of light spots from a single optical head or from a plurality of optical heads on the same or different recording tracks and simultaneously record them. By using a plurality of light spots, speeding up can be realized. In addition, this recording apparatus is compatible with a system for recording information on a land out of a groove and a land (an irregular version of a so-called in-groove recording system).

  When mark edge recording is performed under the above conditions, the mark length of the 3T mark, which is the shortest mark, is about 0.20 μm, and the mark length of the 14T mark, which is the longest mark, is about 1.96 μm. The recording signal includes repeated dummy data of 4T mark and 4T space at the start and end of the information signal. VFO is also included in the start end. In mark edge recording, the positions of both ends of a recording mark formed on a recording film are made to correspond to 1 of the digital data, so that the length of the shortest recording mark is reduced to 2 to 3 instead of one reference clock. Correspondingly, the density can be increased.

As a material for the transparent electrode, a composition of (In ₂ O ₃ ) _x (SnO ₂ ) _1-x , where x is in the range of 5% to 99%, more preferably in terms of resistance, x is 90% To 98% of material, to which 50% or less of SiO ₂ is added to this, SnO ₂ to which other oxides such as ₂ to 5% of Sb ₂ O ₃ are added, And known transparent electrode materials, and conductive organic materials such as polythiophene and polyacetylene described in detail in Example 2 can be used.

  In this embodiment, a polycarbonate substrate having a tracking groove directly on the surface is used. A substrate having a tracking groove is a substrate having a groove with a depth greater than or equal to λ / 15n (n is the refractive index of the substrate material) when the recording / reproducing wavelength is λ on the entire surface or part of the substrate surface. is there. The groove may be formed continuously in one round or may be divided in the middle. It has been found that when the groove depth is about λ / 12n, it is preferable in terms of the balance between tracking and noise. Further, the groove width may vary depending on the location. A substrate having a format capable of recording / reproducing in both the groove portion and the land portion may be used, or a substrate having a format in which recording is performed on one of them may be used. In the type of recording only in the groove, it is preferable that the track pitch is about 0.7 times the wavelength / NA of the focusing lens, and the groove width is about a half thereof.

The recorded information was also reproduced using the optical head. At the time of reproduction, firstly, the recording area storing the management information indicating the correspondence between the recording area and the write information forming the logical group is read. According to the information stored there, the recording area selecting unit 92 applies a voltage to the selected predetermined layer to color it, irradiates the recorded mark with laser light, and reflects it from the mark and the part other than the mark. By detecting light, the writing information forming the logical group is reproduced. In the mark portion, the coloring function is lost due to the laser light irradiation at the time of recording and the color is light, so that a reproduction signal can be obtained. In this example, it was presumed that H ⁺ was not easily inserted into the tungsten oxide used as the electrochromic material due to laser light irradiation, and it was difficult to color. The amplitude of the reproduction signal is increased by the preamplifier circuit 84, and converted into 8-bit information every 16 bits by the 8-16 demodulator 89. With the above operation, the reproduction of the recorded mark is completed.

  It is not necessary for all management information to be stored in the information recording medium. -When storing information predetermined at the time of distribution as in the ROM type, only a unique ID is recorded on the disk, and a recording area recorded as a table in the memory in the drive from the read ID during reproduction The management information corresponding to the ID may be read out from the management information indicating the correspondence of the write information forming the logical group. Thereafter, management information newly created in the disk by a restoration operation described later can be read, and the logical group distributed and stored in the disk can be reproduced.

  As shown in FIG. 9A, a series of data forming a logical group is distributed and stored in a plurality of recording areas 43a, 44b, and 45c, and processing when the recording area 43a fails due to an accident. Will be described. The layer structure is the same as in FIG. It is assumed that the management information indicating the correspondence between the recording area and the write information forming the logical group is stored in the recording area 47a.

  FIG. 10 shows a processing flow by the information recording / reproducing apparatus of the present invention. First, in step 11, the recording area selection unit 92 of the information recording / reproducing apparatus selects the recording area 47a in which the management information is recorded to be colored, and reproduces the management information by irradiating the reproducing light from the head. The selected recording area 47a is colored by applying a voltage between the upper and lower electrodes sandwiching the recording area 47a. The information recording / reproducing apparatus recognizes that the desired continuous data constituting the logical group is distributed and stored in the recording areas 43a, 44b, 45c from the reproduced management information. Next, in step 12, the recording area 47a from which data has been read is unselected and returned to the decolored state. In order to return the recording area 47a to the decolored state, voltage application to the electrodes sandwiching the recording area 47a from above and below is cut off. Next, in step 13, the recording area selection unit 92 selects the corresponding recording areas 43a, 44b, and 45c so as to be colored, and in step 14, it is determined whether or not all the selected recording areas are colored. If all the recording areas are colored, the process proceeds to step 15 to reproduce data from the colored recording areas 43a, 44b, 45c. At this time, as shown in FIG. 9B, since the three-layer recording areas 43a, 44b, and 45c are within the focal depth of the reproduction laser beam, the recording areas 43a, 43b, Data recorded in 44b and 45c can be read out continuously. Next, in step 16, the host computer reproduces information recorded in a plurality of layers and acquires target information.

  Next, processing when the recording area 43a is not colored in the determination in step 14 will be described. In this case, since the information cannot be read out even though the recording area 43a is selected, the controller confirms that the recording area 43a has failed. In step 17, the controller selects and blanks the blank area 46a on which nothing is recorded. Then, the head is read again. The reason for selecting the blank area is to prevent the drive-side autofocus from being removed. In step 18, the recording areas 44b, 45c and 46a are reproduced, and only the information recorded in the recording areas 44b and 45c is reproduced. In step 19, the host computer calculates the exclusive OR of the parity-added data blocks read from the recording areas 44b and 45c, restores the data blocks in the recording area 43a, and temporarily stores them in the memory in the drive. . In step 20, the restored data in the recording area 43a is recorded in an unused recording area, for example, the recording area 46a. Further, in step 21, the new management information of this time is added to the recording area 47a in which the management information indicating the correspondence between the recording area and the write information forming the logical group is stored. When data is reproduced from the next time by updating the management information, the updated management information is read first, and the recording area 46a storing the restored data is selected instead of the recording area 43a in which the failure has occurred. . Next, proceeding to step 22, the recording areas 46a, 44b and 45c are selected and the recorded data is read out. In step 16, the host computer reproduces information recorded in a plurality of layers and acquires the target information.

  In order to realize a large capacity in the voltage selective optical disc, it is necessary to stack as many recording layers as possible. On the other hand, it is necessary to increase the transparency by holding the transparent electrodes as small as possible by sharing the transparent electrodes between the upper and lower recording layers. In such a case where a common electrode is used in the upper and lower recording layers, in the case where an unexpected situation occurs and the transparent electrode is damaged, recording / reproduction is performed with two recording layers adjacent to the upper and lower sides of the damaged transparent electrode. Can be assumed to be impossible. For example, when the recording area 44b cannot be selected, a similar selection error occurs with a high probability in the recording area 43b using the common transparent electrode or the recording area 45b.

  Therefore, when a selection error occurs when a certain recording area is selected, the processing flow includes a step for checking whether a layer selection error has occurred in the upper and lower two recording areas having the same transparent electrode as the recording area where the error has occurred. May be added. The confirmation can be performed by monitoring the current value of the voltage application unit provided in the drive. When an error is confirmed, the recording area is also restored. Data restoration takes top priority on the selected recording area, and restoration of the adjacent recording area across the transparent electrode is performed after reading a series of information, that is, when access to the disk decreases. What should I do? The controller / host computer / memory unit necessary for restoration may be expanded and two recording areas may be restored simultaneously.

[Embodiment 2] Multilayer Laminate Planar Hologram-Light Selection FIG. 11 is a diagram for explaining an example of a production process of a reproduction-only multiplex hologram card according to the present invention. This card has a layer structure in which an ultraviolet curable resin and PMMA (polymethyl methacrylate) are alternately stacked. The ultraviolet curable resin has a refractive index of 1.480 and a thickness of 8 μm, and PMMA has a refractive index of 1. .492 and a thickness of 1.7 μm.

  The production method is as follows. First, an ultraviolet curable resin 50 is spin-coated on a 1-inch square optically polished glass substrate 49 with a thickness of 8 μm, exposed to ultraviolet light 51, and then PMMA 52 is spin-coated with a thickness of 1.7 μm. Then, a pattern is transferred using a transparent stamper 53 with a UV-absorbing pattern with a period of 0.46 μm and a low UV absorption. This UV curing resin coating, curing by UV exposure, PMMA coating, stamper transfer to PMMA is repeated for a total of 10 cycles, 10 layers of recording layers are laminated, and finally a UV curing resin layer is formed as a protective layer Thus, a planar waveguide having a periodic layer structure was obtained. In this case, the ultraviolet curable resin layer is a clad and the PMMA layer is a core, and an uneven pattern as a periodic scattering factor is formed on each core layer by a stamper.

  The recording area can be divided by changing the uneven pattern of the stamper. FIG. 12 shows an example in which one recording layer is divided into four recording areas 54a, 54b, 54c, and 54d. Although only one recording layer is shown in the drawing, a plurality of recording layers are laminated to constitute an information recording medium. Lights 55a, 55b, 55c, and 55d incident on the optical waveguides in the respective recording regions by the cylindrical lenses 56a, 56b, 56c, and 56d are changed in incident direction by 90 degrees in a plane parallel to the recording layer. This takes into consideration that the end face to which incident light of the information recording medium is applied is damaged, and information can be recorded / reproduced from the recording areas provided in the remaining three places even if light cannot enter from a specific end face. I did it. The four cylindrical lenses 56a, 56b, 56c, and 56d are independently driven in the recording layer stacking direction, and can make sheet-like light incident on the recording area of the desired recording layer. One end surface of the recording medium was polished at 45 ° as shown in FIG. With this processing, light can be incident on a plurality of recording areas as shown in FIG. 12, not from the side surface (four directions) of the recording film, but from directly below or directly above (one direction) as shown in FIG. It becomes. This means that the apparatus configuration is easy in terms of the light source / optical system arrangement.

  As in the first embodiment, the information provided with parity in a form close to RAID 5 is distributed and stored in different recording areas a, b, c, and d of different recording layers. A semiconductor laser beam having a wavelength of 680 nm was used as a light source, and after being shaped into a parallel beam having a diameter of 5 mm by a collimator lens, it was condensed into a sheet-like beam by cylindrical lenses 56a, 56b, 56c, and 56d having a focal length of 13 mm. When the focus of the laser beam 55 is adjusted to the 45 ° cut position of the target PMMA layer, diffracted beams 57 and 58 appear in the vertical direction.

  This hologram card requires an operation of condensing laser light at a predetermined position with a lens, like a normal optical disk. However, the optical disk reproduces information on the surface of the disk bit by bit by changing the focusing position, whereas the hologram card according to the present invention changes the image (two-dimensional information) by changing the focusing position. To do. Since there is no change in reading the information by changing the condensing position, the alignment of the condensing position is important in terms of both the alignment speed and accuracy as in the case of the optical disc.

  As shown in FIG. 14A, the information is distributed and stored in a plurality of recording areas 59a, 60b, 61c, and 62d. In reproducing information, a plurality of recording areas are simultaneously reproduced, and a complete reproduction image obtained by combining the reproduction images from the four recording areas is acquired. Here, processing when the recording area 59a fails due to an unexpected accident will be described. First, the management information stored in 63a is read, the recording areas 59a, 60b, 61c and 62d are selected, and the diffraction pattern is detected by the CCD. The state at this time is shown in FIG.

  The image in the recording area 59a includes leakage of information in other recording areas and includes crosstalk. At this time, when the abnormality of the image is detected by the CCD, the controller selects the blank recording area 64a where nothing is recorded as the incident area of the sheet beam irradiated by the cylindrical lens 56a. The reason for selecting the blank layer is to analyze an image including crosstalk so that erroneous data is not reproduced.

  The host computer calculates the exclusive OR of the parity-added data blocks read from the remaining recording areas 60b, 61c and 62d detected by the CCD, and restores the data blocks in the recording area 59a. The restored data block information of the recording area 59a is stored in the memory in the temporary drive and recorded in the unused recording area 61a.

  Then, the new management information of this time is added to the recording area 63a storing the management information indicating the correspondence between the recording area and the writing information forming the logical group. When data is reproduced after the next time, the updated management information is read first, and the recording area 59a in which the failure has occurred is not selected, but the recording area 61a in which the restored information is stored is selected.

[Embodiment 3] Layer Selective Card-Light Selection An embodiment of a card type multilayer recording medium in which layer selection is performed according to the position of incident light will be described.
In this embodiment, the mechanism for selecting a recording area in the apparatus configuration is the same as that in the second embodiment, but a read-only light source and head are used instead of a CCD for reading data. Further, as the recording medium was produced only writable (W rite O nce) medium once. A photochromic material (diarylethene) is used for the core layer corresponding to the recording area. The core layer was prepared by dispersing diarylethene in PMMA used in Example 2. The PMMA layer and the diarylethene layer may be separated, but in order to realize an optical waveguide, the PMMA layer must be adjusted to have a refractive index close to 1.49. Diarylethene is colored by light incident at a wavelength of 400 nm, and an absorption band is generated from a wavelength of 500 nm to 600 nm only when colored.

  The production method of the multilayer recording medium is the same as that for the reproduction-only multiple hologram card except that diarylethene is added to the core layer. First, a 1-inch square optically polished glass substrate was spin-coated with an ultraviolet curable resin with a thickness of 8 μm, exposed to ultraviolet light, and then PMMA 51 added with 5% by weight of diarylethene was spin-coated with a thickness of 1.7 μm. Then, a pattern is transferred using a transparent stamper 53 with a UV-absorbing pattern with a period of 0.46 μm and a low UV absorption. This UV curing resin coat, curing by UV exposure, PMMA coating, stamper transfer to PMMA is repeated for a total of 5 cycles, and after 5 recording layers are laminated, an ultraviolet curing resin layer is finally formed as a protective layer Thus, a planar waveguide having a periodic layer structure was obtained.

  In this case, the concave / convex pattern formed by the ultraviolet curable resin layer as the cladding and the PMMA layer as the core and formed by the stamper in each core layer guides the light source for reproduction, not the function of the periodic scattering factor in the second embodiment. It is a groove for. Since color development occurs only in pits with a large amount of added diarylethene, signals can be obtained from the contrast of darkly colored pits and non-pit areas where little coloring occurs in the selected recording area, enabling selective readout. It is. When a high-power laser is used as a light source for recording and heated to a decomposition temperature of 200 ° C. or higher, the diarylethene is not colored again. In such a write-once type, it is preferable that the photochromic material is uniformly distributed in the recording area, rather than being concentrated only on the pits as in the ROM medium.

  Since such a -ROM and -R mixed multi-layer card has the same ROM layer as a single-layer ROM, it can be read by many devices, and a user having a recordable device can record on the -R layer. Since it is possible to refer to the ROM layer at the time of recording, the merit as a recording medium is very large.

  The structure of the information recording medium was card-like as in Example 2. The recording area can be divided by changing the uneven pattern of the stamper. FIG. 15 shows an example in which one recording layer is divided into three recording areas 65a, 65b, and 65c. Although only one recording layer is shown in the figure, a plurality of recording layers are stacked to constitute a card type medium. Lights 66a, 66b, and 66c incident on the optical waveguides in the respective recording areas by the cylindrical lenses 67a, 67b, and 67c are changed by 180 degrees in a plane parallel to the recording layer. This is because the end face of the information recording medium irradiated with the incident light may be damaged. Even if light cannot be incident only from a specific end face, the information can be recorded / reproduced from the remaining two recording areas. This is to make it possible. In addition, since the card-type medium is read by laser scanning, all the divided areas are included in the laser scanning locus. The three cylindrical lenses 67a, 67b, and 67c can be independently positioned in the recording layer stacking direction, and sheet-like light can be incident on a recording area of a desired recording layer.

  FIG. 16 is a block diagram illustrating a configuration example of an information recording / reproducing apparatus using a card type multilayer recording medium that performs layer selection by light selection according to the present embodiment. The recording area is selected by selecting the light incident positions of a plurality (three in this embodiment) of recording area selecting optical heads by the recording area selecting section 92. The three recording area selecting optical heads correspond to the three cylindrical lenses 67a, 67b, 67c. One end surface of the recording medium was polished at 45 ° as shown in FIG. With this processing, light can be incident on a plurality of recording areas as shown in FIG. 15, not from the side surface (four directions) of the recording film, but from directly below or directly above (one direction) as shown in FIG. It becomes. This means that the apparatus configuration is easy in terms of the light source / optical system arrangement.

  As in the first embodiment, the information provided with parity in a form close to RAID 5 is distributed and stored in different recording areas a, b, and c of different recording layers. In recording information, the recording areas of a plurality of recording layers on which information is to be recorded are irradiated with a sheet-like beam from the side as shown in FIG. 15 to color the recording areas. After that, recording is performed while recording light is scanned from the film thickness direction of the medium. At this time, the recording layer is selected so that the plurality of recording areas are all within the focal depth of the recording light. As a result, the recording operation can be performed in the same manner as recording information on a single recording film as in the past, without being conscious of the fact that individual recording areas exist at different positions in the film thickness direction. Can do.

  A semiconductor laser beam having a wavelength of 405 nm was used as a light source. After being shaped into a parallel beam having a diameter of 5 mm by a collimator lens, the light was condensed as a sheet-like beam by cylindrical lenses 67a, 67b and 67c having a focal length of 13 mm. The information of the selected recording area was read out by an Ar laser having a wavelength of 514 nm as the reproducing laser 68 in accordance with the focus of the laser beam irradiated from the recording area selecting optical head at the 45 ° cut position of the target PMMA layer. .

  As shown in FIG. 18A, data stored in the recording areas 69a, 70b, and 71c and stored, and processing when the recording area 69a fails due to an unexpected accident will be described. First, the management information stored in the recording area 72a is read, the recording areas 69a, 70b, 71c are selected, and reproduction is performed using a reproduction laser. The state at this time is shown in FIG. As shown in FIG. 15, the recording area for reproducing the information is selected by coloring the selected recording area with incident light from the side.

  At this time, an abnormality in the recording area 69a, for example, when information cannot be obtained from the recording area 69a, or light in the adjacent recording area 70b leaks into the recording area 69a, and light for reproducing the recording area 69a is reproduced in 70b. In the case where the crosstalk between adjacent recording areas where the desired information is not obtained and the reproduction signal quality deteriorates when the light is detected for including the light for the controller, the controller records a blank recording area where nothing is recorded 73a is selected. The reason for selecting the blank layer is to prevent reproduction of data including crosstalk. Then, the host computer calculates the exclusive OR of the parity added data blocks read from the remaining recording areas 70b and 71c detected by the reproducing head, and restores the data blocks in the recording area 69a. The restored data block information of the recording area 69a is stored in the memory in the temporary drive and recorded in the unused recording area 71a.

  Then, the new management information of this time is added to the recording area 72a in which the management information indicating the correspondence between the recording area and the write information forming the logical group is stored. When the data is reproduced after the next time, the updated management information is read first, and the recording area 69a in which the restored information is stored is selected without selecting the recording area 69a in which the failure has occurred in advance. Then, by reproducing the recording areas 71a, 70b, 71c, desired data can be obtained.

FIG. 3 is a schematic cross-sectional view showing a configuration example of a voltage layer selective multilayer recording medium. The figure which shows the structural example of a hologram memory. The block diagram which shows an example of the system containing the multilayer information recording medium to which RAID4 was applied by this invention. The figure which shows the structural example of the layer selection type optical disk by voltage selection. The figure which shows the structural example which divided | segmented one recording layer of the layer selection type optical disk by voltage selection into the some recording area. The figure which shows the structural example which divided | segmented one recording layer of the layer selection type optical disk by voltage selection into the several recording area. The figure which shows the structural example of the disc holder part which sets an information recording medium and a medium. The block diagram which shows the structural example of the information recording / reproducing apparatus using the layer selection type multilayer recording medium by voltage selection. The figure which shows the coloring of the recording area at the time of the information reproduction of the layer selection type optical disk by voltage selection. The flowchart explaining the information reproduction | regeneration at the time of abnormality occurrence. Explanatory drawing of the manufacturing process of a reproduction-only multiple hologram card. The figure which shows the structural example which divided | segmented one recording layer of the read-only multiple hologram card into the several recording area. The figure which shows the positional relationship of the incident light and diffracted light of the read-only multiple hologram card which has the divided | segmented recording area. Explanatory drawing at the time of information reproduction | regeneration of the reproduction | regeneration only multiple hologram card which has the divided | segmented recording area. The figure which shows the structural example of the layer selection type optical card by light selection. The block diagram which shows the structural example of the information recording / reproducing apparatus using the card type multilayer recording medium which performs layer selection by light selection. The figure which shows reproducing | regenerating operation | movement of the layer selection type | mold optical card by the optical selection which has the divided | segmented recording area. The figure which shows reproducing | regenerating operation | movement of the layer selection type | mold optical card by the optical selection which has the divided | segmented recording area.

Explanation of symbols

1: Substrate 2: Protective layer 3: First electrode (transparent electrode)
4: Electrochromic material layer 5: Second electrode (transparent electrode)
6: insulator layer 7: UV curable resin layer 8: protective substrate 9: groove portion 10: land portion 12a: clad layer 12b: core layer 13a: clad layer 13b: core layer 14a: clad layer 14b: core layer 15: clad Layer 16: Reproduction illumination light source 17: Reproduction illumination light 18: Diffracted light 19: Hologram image 20: Multilayer information recording medium 21: Recording layer (first layer)
22: Recording layer (second layer)
23: Recording layer (third layer)
24: Parity storage recording area (fourth layer)
25: Controller 26: Disk I / F
27: Host computer 28: Substrate 29: Translucent reflective layer 30: Transparent electrode 31: Electrochromic material layer 32: Ion passage control layer 33: Solid electrolyte layer 34: Transparent electrode 35a: Recording area 35b of the first area a 1st layer b area recording area 35c: 1st layer c area recording area 36a: 2nd layer a area recording area 36b: 2nd layer b area recording area 36c: 2nd layer c area Area recording area 37a: Third layer a area recording area 37b: Third layer b area recording area 37c: Third layer c area recording area 38: Recording / reproducing laser 39: Disc receiving section 40: Concentric circle split electrode 41: Concentric circle arrangement pin electrode 42: Lead electrode 43a: Recording area in area a of the first layer (distributed data recording unit 1/3)
43b: recording area of the b area of the first layer 43c: recording area of the c area of the first layer 44a: recording area of the a layer of the second layer 44b: recording area of the b area of the second layer (distributed data recording unit 2) / 3)
44c: recording area 45a of the second layer c area 45a: recording area of the third layer a area (unused recording area)
45b: b area recording area 45c of the third layer: c area recording area of the third layer (distributed data recording unit 3/3)
46a: recording area (blank area) of area a of the fourth layer
46b: recording area (blank area) of area b of the fourth layer
46c: recording area (blank area) of c area of the fourth layer
47a: recording area of area a of the fourth layer (management information storage unit)
47b: b area recording area 47c of the 4th layer 47c: recording area 48c of the 4th layer c: recording / reproducing laser 49: glass substrate 50: UV curable resin 51: UV light 52: PMMA
53: Transparent stamper 54a: recording area 54b of the first layer a area 54b: recording area 54b of the first layer b: recording area 54d of the first layer c area 54d: recording area 55a of the first layer d area: Light 55b incident on the recording area of the first area a area 55b: Light incident on the recording area of area b of the first layer 55c: Light 55d incident on the recording area of area c of the first layer Light 56a incident on the recording area in the d area of the eye: Cylindrical lens 56b that condenses light incident on the recording area in the a area: Cylindrical lens 56c that condenses light incident on the recording area in the b area: Cylindrical lens 56d for condensing light incident on the recording area in area c: Cylindrical lens 57 for condensing light incident on the recording area in area d: diffracted light 58: diffracted light 59a: first layer Recording region of the area (distributed data recording unit 1/4)
60b: recording area of b area of second layer (distributed data recording unit 2/4)
61a: recording area of area a of the third layer (unused recording area)
61c: recording area of c area of third layer (distributed data recording unit 3/4)
62d: recording area of d area of fourth layer (distributed data recording unit 4/4)
63a: recording area of area a in the fifth layer (management information storage unit)
64a: Blank recording area 65a in the a area of the fifth layer: Recording area 65b in the first layer a area 65b: Recording area 65c in the first layer b area: Recording area 66a in the first layer c area 66a: First layer Light 66b that is incident on the recording area in area a, light 66c that is incident on the recording area in area b of the first layer, light 67c that is incident on the recording area in area c of the first layer 67a: recording area in area a Cylindrical lens 67b that condenses the light incident on the recording area 67b: Cylindrical lens 67c that condenses the light incident on the recording area in the area b: Cylindrical lens 68 that condenses the light incident on the recording area in the area c: Reproduction Laser beam 69a: recording area of area a of the first layer (dispersed data recording unit 1/3)
70b: recording area of b area of second layer (distributed data recording unit 2/3)
71a: recording area of area a of the third layer (unused recording area)
71c: recording area of c area of third layer (distributed data recording unit 1/3)
72a: recording area of area a of the fourth layer (management information storage unit)
73a: blank recording area 81 in area a of the fifth layer 81: information recording medium 82: motor 83: optical head 84: preamplifier circuit 85: recording waveform generation circuit 86: laser drive circuit 87: 8-16 modulator 88: L / G servo circuit 89: 8-16 demodulator 91: data processor 92: recording area selector

Claims (12)

Each of the recording layers has a plurality of recording layers formed by being laminated, and each recording layer is divided into a plurality of recording areas that can be independently selected, and the corresponding recording area of each recording layer is the stacking direction of the recording layers Using an information recording medium that can be recorded by irradiating recording light only to a selected recording area,
From a plurality of recording layers within the focal depth of the recording light, select a plurality of recording areas belonging to different recording layers and not overlapping in the focal depth direction,
An information recording method characterized in that write information forming a logical group is distributed and recorded in the selected plurality of recording areas. The information recording method according to claim 1 ,
The recording layer has an electrochromic material layer;
The selection of the recording area is performed by applying a voltage to the recording area,
An information recording method, wherein information is recorded by irradiating the recording light to a recording area whose optical properties have been changed by applying the voltage. The information recording method according to claim 1 ,
The recording layer is a core layer containing a photochromic material sandwiched between clad layers,
The recording area is selected by making light incident on the core layer,
An information recording method, wherein information is recorded by irradiating the recording light onto a recording area whose optical properties have been changed by the incident light. 2. The information recording method according to claim 1 , wherein management information indicating a correspondence between the recording area and the writing information forming the logical group is recorded on the information recording medium. 2. The information recording method according to claim 1 , wherein the write information forming the logical group includes a plurality of data blocks obtained by dividing user data and parity data generated from the divided data blocks. An information recording method, wherein a data block and the parity data are distributed and recorded in different recording areas. The recording layer has a plurality of recording layers, each recording layer is divided into a plurality of recording areas that can be independently selected, and the corresponding recording area of each recording layer is the stacking direction of the recording layers A medium holding unit for holding an information recording medium that is arranged so as to overlap with the selected recording area and can be recorded by irradiation of recording light only;
An optical head that includes a light source that generates recording light and is movable with respect to the information recording medium held in the medium holding unit;
A data processing unit that divides write information forming a logical group into a plurality of data blocks and generates parity data from the divided data blocks;
Recording area selection for selecting, from a plurality of recording layers within the focal depth of the recording light, a number of recording areas equal to or greater than the number of data blocks so that they belong to different recording layers and do not overlap in the focal depth direction And
A recording processing unit that performs a recording operation by associating the plurality of data blocks and the parity data with the selected plurality of recording areas on a one-to-one basis,
An information recording apparatus, wherein write information forming the logical group is distributed and recorded in the selected plurality of recording areas. 7. The information recording apparatus according to claim 6 , wherein one record of the information recording medium held in the medium holding unit as management information is a correspondence relationship between the plurality of data blocks and the parity data and the plurality of selected recording areas. An information recording apparatus for recording in an area. The information recording apparatus according to claim 6 , wherein
The information recording medium has an electrochromic material layer as the recording layer and a plurality of transparent electrode layers formed so as to sandwich the electrochromic material layer for each recording region,
The medium holding unit includes a plurality of electrodes in contact with each of the plurality of transparent electrode layers,
The recording area selection unit applies a voltage to a pair of transparent electrodes sandwiching a desired recording area via an electrode provided in the medium holding unit,
An information recording apparatus for recording information by irradiating the recording light to a recording area whose optical properties have been changed by applying the voltage. 9. The information recording apparatus according to claim 8 , wherein the recording area is divided and arranged in a circumferential direction of the recording layer. 9. The information recording apparatus according to claim 8 , wherein the recording area is partitioned in the circumferential direction of the recording layer and is also partitioned in the radial direction. The information recording apparatus according to claim 6 , wherein
The information recording medium has a core layer having a photochromic material as the recording layer and a cladding layer sandwiching the core layer,
The recording area selecting means includes a plurality of optical means for causing the sheet-like incident light to enter the core layer, and a means for moving the optical means independently in the stacking direction of the recording layers. ,
An information recording apparatus for recording information by irradiating the recording light on a recording area whose optical properties have been changed by light incidence from the recording area selecting means. 12. The information recording apparatus according to claim 11 , wherein the recording layer has a rectangular shape, and the recording area has a rectangular shape in which two opposing sides are the same length as the recording layer.

Images