JP4308876B2 - Optical recording medium and information recording method - Google Patents

Description

  The present invention relates to an optical recording medium and an information recording method that include recording layers having a multilayer structure each having a track for guiding recording light, and capable of recording user data in each recording layer.

  As recordable DVD disks, there are DVD + R which is a recordable DVD disk and DVD + RW which is a rewritable DVD disk, and these disks are recordable DVD disks which have high reproduction compatibility with a single-sided single-layer reproduction-only DVD disk. Research and development for increasing the speed and capacity of such recordable discs has been actively conducted.

  As described above, in an optical recording medium having a plurality of stacked recording layers, the recording / reproducing light to the recording layer disposed behind the light incident surface passes through the preceding recording layer. Therefore, in the optical recording medium in which the optical characteristics of the recording layer are changed by changing the intensity of the recording light, the waveform conditions and intensity conditions of the recording light are different. When recording is sequentially performed on a plurality of recording layers, the waveform condition and intensity condition of the recording light change from the start of recording due to heat generated during recording of recording information. Therefore, different waveform conditions and intensity conditions are required for the optical recording medium having a single recording layer.

For this reason, for example, according to Patent Document 1, information specifying the data layer and recording conditions of the data layer are reflected in the data layer in a direction in which the recording track extends. There is a proposed example in which the rate region and the high reflectivity region are provided in a bar code shape alternately existing.
JP 2002-50053 A

  However, the proposed example described in Patent Document 1 is based on the fact that data layer specific information can be read without performing tracking servo, and as an optical pickup, the original operation is specific to the data layer. Not only can information not be read, but also the portion occupied by the data layer specific information area = barcode information area cannot be used for information recording, resulting in extremely low recording information density.

  The present invention, in a multilayer structure having a plurality of recording layers, does not require extra movement of the optical pickup, allows reading of layer information for identifying each recording layer and trial writing processing, and proceeds to a recording operation as it is. An object of the present invention is to provide an optical recording medium that can be used.

  In addition, an object of the present invention is to make it possible to recognize a recording condition suitable for each recording layer by an original optical pickup operation and to provide a good recording operation.

  In addition, an object of the present invention is to make it possible to read a recording condition without being affected by a recording signal in a data area.

  According to the first aspect of the present invention, there is provided an optical track recording system having an opposite track path type multi-layered recording layer each having a spiral track for guiding recording light and capable of recording data in each recording layer. A medium in which a test writing area, which is trial-written to determine a recording condition for recording data on each recording layer, has a spiral direction of the track from the inner circumference side to the outer circumference side during recording and reproduction. Has at least an inner peripheral portion, and has at least an outer peripheral portion in the case of going from the outer peripheral side to the inner peripheral side, and the layer information for identifying each recording layer includes a spiral direction of the track during recording and reproduction. When it goes from the inner peripheral side to the outer peripheral side, it has at least the inner peripheral part, and when it goes from the outer peripheral side to the inner peripheral side, it has at least the outer peripheral part.

  In general, trial writing is performed in the trial writing area in order to determine the recording condition. However, such a trial writing area is provided in each recording layer, and the inner peripheral portion or the outer peripheral portion is matched to the spiral direction. By setting in the area, it is possible to perform the test writing process without moving the optical pickup and move to the recording operation as it is. Also, the track is often formed in a spiral shape, but when the spiral direction of the track goes from the inner peripheral side to the outer peripheral side, the inner peripheral portion, and when going from the outer peripheral side to the inner peripheral side, the outer periphery Since each part has information on recording conditions, etc., the optical pickup coincides with the first access side at the start of the recording operation for the recording layer, and no extra movement of the optical pickup is required. The layer information to be identified can be read, and the recording operation can be shifted as it is.

  According to a second aspect of the present invention, in the optical recording medium according to the first aspect, layer information for identifying each recording layer is preformatted on the track itself.

  Therefore, by providing the layer information for identifying each recording layer as an information signal on the track (guide pit or guide groove), the recording condition suitable for each recording layer can be realized by the original optical pickup operation to follow the track. Can be recognized, and can be used for a good recording operation. Further, as layer information for identifying each recording layer, for example, normal pits or recording marks may be recorded, but by preformatting the track itself as information on the track, the data area Necessary information can be embedded without reducing.

  According to a third aspect of the present invention, in the optical recording medium according to the second aspect, the recording layer of the multilayer structure includes an odd numbered layer and an even numbered layer in which groove tracks and land tracks are alternately arranged as recording positions. It is characterized by being set.

  Accordingly, when recording on a recording layer having a multi-layer structure, as a track, recording is normally performed only on the groove, recorded only on the land, or recorded on the land or on the land. However, the present invention can be applied without any problem when the recording positions of the odd-numbered layer and the even-numbered layer are alternately set to the groove track and the land track.

  According to a fourth aspect of the present invention, in the optical recording medium according to the second or third aspect, the layer information for identifying each recording layer is preformatted as pits or grooves constituting the track. And

  Therefore, by pre-formatting layer information for identifying each recording layer as pits or grooves formed on a transparent substrate and constituting a track, a medium can be easily produced at low cost.

  According to a fifth aspect of the present invention, in the optical recording medium according to any one of the second to fourth aspects, layer information for identifying each recording layer is preformatted on the track itself by phase modulation. It is characterized by that.

  Therefore, as a method for preformatting information on the track itself, there are methods such as periodic modulation and amplitude modulation, but the intensity variation of reflected light is large depending on the state of the recording medium, and the synchronization signal is as high as 100 kHz. When the DVD + R / RW type having a period is assumed, phase modulation is suitable.

  According to a sixth aspect of the present invention, in the optical recording medium according to any one of the first to fifth aspects, layer information for identifying each recording layer is provided on the track outside the data area. Features.

  Therefore, since the signal SN of the signal on the track changes before and after the information is recorded on the recording layer, avoid the data area as a position for recording the layer information for identifying each recording layer on the track. In the case of a concentric or spiral track, the data area is often provided in the middle area, so generally it is provided in one or both of the inner and outer circumferences. Is preferred.

  According to a seventh aspect of the present invention, in the optical recording medium according to any one of the first to sixth aspects, each of the recording layers individually has layer information for identifying each of the recording layers. Features.

  Therefore, by having the layer information for identifying each recording layer individually for each recording layer, it is possible to appropriately set the recording conditions for each recording layer, and the conditions such as the recording conditions for each recording layer. Can be expanded without changing the format of recording conditions even when the number of recording layers increases, etc., and it is easy to achieve compatibility with the case of single-layered optical recording media that are already in widespread use. It will be a thing.

  According to an eighth aspect of the present invention, in the optical recording medium according to any one of the first to seventh aspects, the recording layer to be recorded first is located closest to the front side when viewed from the incident side of the recording light. It is characterized by being located.

  Therefore, the recording layer to be recorded first is the recording layer that is positioned closest to the incident side of the recording light that is most unaffected by the other recording layers, so that the recording conditions and the like can be read out satisfactorily. It can be carried out.

  According to a ninth aspect of the present invention, in the optical recording medium according to any one of the first to seventh aspects, the first recording layer to be recorded is located on the innermost side when viewed from the incident side of the recording light. It is characterized by being located.

  Therefore, the first recording layer is the recording layer that is located at the farthest position when viewed from the incident surface side of the recording light, and the influence of the preceding recording layer during recording on the recording layer on the near side thereafter Recording can be performed without being affected, so that stable recording can be performed.

  According to a tenth aspect of the present invention, in the optical recording medium according to any one of the first to ninth aspects, each recording layer is transparent to the wavelength of the recording light and forms a track. It is characterized by being laminated on a substrate.

  Therefore, the optical recording medium according to any one of claims 1 to 9 can be provided simply and inexpensively.

  According to an eleventh aspect of the present invention, in the optical recording medium according to any one of the first to tenth aspects, the recording layer has two recording layers on one side in accordance with the DVD + R standard.

  Therefore, the present invention can be suitably applied to a write-once type optical recording medium that complies with the DVD + R standard and has two recording layers on one side.

  According to a twelfth aspect of the present invention, in the optical recording medium according to any one of the first to tenth aspects of the present invention, the optical recording medium has a single-sided, two-layered recording layer based on the DVD + RW standard.

  Therefore, the present invention can be suitably applied to a rewritable optical recording medium that complies with the DVD + RW standard and has two recording layers on one side.

  According to a thirteenth aspect of the present invention, in the information recording method, a step of recording data on one of the recording layers included in the optical recording medium according to any one of the first to twelfth aspects, and the recording of the data A test writing to the test writing area of the recording layer adjacent to the recording layer to determine the recording conditions, and a step of recording data to the adjacent recording layer under the determined recording conditions. Features.

  In general, trial writing is performed in the trial writing area in order to determine the recording condition. However, such a trial writing area is provided in each recording layer, and the inner peripheral portion or the outer peripheral portion is matched to the spiral direction. By setting in the unit, it is possible to perform the test writing process without moving the optical pickup and move to the recording operation as it is. Also, the track is often formed in a spiral shape, but when the spiral direction of the track goes from the inner peripheral side to the outer peripheral side, the inner peripheral portion, and when going from the outer peripheral side to the inner peripheral side, the outer periphery Each of the recording layers has information on recording conditions, etc., so that when the recording operation for the recording layer is started, the optical pickup coincides with the first access side, and no extra movement of the optical pickup is required. Can be read out, and the recording operation can be shifted as it is.

  According to the first aspect of the present invention, the trial writing is generally performed in the test writing area in order to determine the recording condition. However, such a test writing area is provided in each recording layer, and By setting the inner peripheral portion or the outer peripheral portion in accordance with the spiral direction, it is possible to shift to the recording operation as it is by performing the test writing process without requiring extra movement of the optical pickup. In addition, when the spiral direction of the track is directed from the inner peripheral side to the outer peripheral side, the outer peripheral portion has information on the recording condition and the like when the head is directed from the outer peripheral side to the inner peripheral side. At the start of the recording operation, the optical pickup coincides with the first accessing side, and it is possible to read the conditions such as the recording conditions without requiring extra movement of the optical pickup, and to proceed to the recording operation as it is. it can.

  According to the second aspect of the invention, in the optical recording medium according to the first aspect, the layer information for identifying each recording layer is provided as the information signal on the track, so that the recording conditions suitable for each recording layer, etc. Can be recognized by an original optical pickup operation that follows the track, and can be used for a good recording operation. Furthermore, as the layer information for identifying each recording layer, for example, it may be recorded by normal pits or recording marks, but since it is preformatted on the track itself as information on the track, Necessary information can be embedded without reducing the data area.

  According to a third aspect of the invention, in the optical recording medium of the second aspect, when recording on a recording layer having a multilayer structure, as a track, as a normal track, any recording layer is on the groove. Recording only on the land, recording only on the land, or recording on both the groove and the land may be adopted, but the recording position of the odd-numbered layer and the even-numbered layer is the groove track. Even when the land track and the land track are alternately set, the present invention can be applied without any trouble.

  According to the invention described in claim 4, in the optical recording medium described in claim 2 or 3, the layer information for identifying each recording layer is preformatted as pit or groove information in the transparent substrate. Media can be made easily at low cost.

  According to a fifth aspect of the invention, in the optical recording medium according to any one of the second to fourth aspects, a method such as periodic modulation or amplitude modulation is used as a method for preformatting information on the track itself. However, since it is a phase modulation method, it can be suitably applied to the DVD + R / RW type in which the intensity fluctuation of the reflected light is large depending on the state of the recording medium and the synchronizing signal has a high period such as 100 kHz. it can.

  According to the invention described in claim 6, in the optical recording medium according to any one of claims 1 to 5, the signal on the track has a signal SN before and after information is recorded on the recording layer. Therefore, it is preferable to avoid the data area as a position for recording information on recording conditions on the track. In the case of a concentric or spiral track, a data area is provided in the middle area. In general, it is preferably provided on one or both of the inner peripheral portion and the outer peripheral portion.

  According to the seventh aspect of the present invention, in the optical recording medium according to any one of the first to sixth aspects, each recording layer is provided with layer information for identifying each recording layer, whereby each recording layer is recorded. It is possible to set the recording conditions for each layer properly and to set the recording conditions for each recording layer, so the recording conditions can be expanded without changing the format of the recording conditions. It can be applied, and compatibility with the case of an optical recording medium having a single layer structure that is already in widespread use can be facilitated.

  According to an eighth aspect of the present invention, in the optical recording medium according to any one of the first to seventh aspects, the recording light that is recorded first is the recording light that is least affected by the other recording layers. By using the recording layer located closest to the incident side of the recording layer, it is possible to satisfactorily read out the recording conditions and the like.

  According to the ninth aspect of the present invention, in the optical recording medium according to any one of the first to seventh aspects, the recording layer to be recorded first is the farthest when viewed from the incident surface side of the recording light. By using the recording layer positioned at the position, since recording can be performed without being affected by the preceding recording layer at the time of recording on the recording layer on the near side thereafter, stable recording can be performed.

  According to the tenth aspect of the present invention, each recording layer is transparent to the wavelength of the recording light, and is laminated on the substrate on which the track for each recording layer is formed. The optical recording medium according to any one of the above can be provided simply and inexpensively.

  According to an eleventh aspect of the present invention, in the optical recording medium according to any one of the first to tenth aspects, a write-once type optical recording medium that conforms to the DVD + R standard and has two recording layers on one side. It can be suitably applied to the target.

  According to the invention described in claim 12, the rewritable optical recording medium according to any one of claims 1 to 10, which is based on the DVD + RW standard and has two recording layers on one side. It can be suitably applied to the target.

  According to the thirteenth aspect of the present invention, the trial writing is generally performed in the test writing area in order to determine the recording condition. However, such a test writing area is provided in each recording layer, and By setting the inner peripheral portion or the outer peripheral portion in accordance with the spiral direction, it is possible to shift to the recording operation as it is by performing the test writing process without requiring extra movement of the optical pickup. In addition, when the spiral direction of the track is directed from the inner peripheral side to the outer peripheral side, the outer peripheral portion has information on the recording condition and the like when the head is directed from the outer peripheral side to the inner peripheral side. At the start of the recording operation, the optical pickup coincides with the first accessing side, and it is possible to read the conditions such as the recording conditions without requiring extra movement of the optical pickup, and to proceed to the recording operation as it is. it can.

  An embodiment of the present invention will be described with reference to the drawings.

[Basic structure of optical recording medium]
In the present embodiment, an application target is an optical recording medium having a multilayer structure in which a plurality of recording layers are stacked in the incident direction of recording / reproducing light. FIG. 1 is a cross-sectional view of an optical recording medium 1 used in the present embodiment. For example, the recording / reproducing light is an example of a single-sided two-layer type in which light is incident only from one recording surface side. The first recording layer 3, the second recording layer 4, and the transparent substrate 5 are sequentially laminated. The first recording layer 3 has a laminated structure of a recording film 6 and a reflective film 7 formed on the transparent substrate 2, and the second recording layer 4 is a reflective film 8 and a recording film 9 formed on the transparent substrate 5. These are integrated by an adhesive film 10.

  Next, details of each layer will be described below.

  First, the recording films 6 and 9 are preferably made of a material whose physical shape or optical property changes due to thermal and / or optical influence caused by the incidence of recording light. For example, in the case of the write-once type one-sided two-layer optical recording medium 1 conforming to the DVD + R standard, in the case of an organic dye material, an azo dye, a cyanine dye, a phthalocyanine dye, a pyrylium dye, an azurenium dye, and squarylium. Dyes, metal complex salt dyes such as Ni and Cr, naphthoquinone dyes, anthraquinone dyes, indophenol dyes, indoaniline dyes, triphenylmethane dyes, triallylmethane dyes, aminium dyes, diimmonium dyes and nitrozo compounds Formazan metal chelates can be mentioned. Among these, azo dyes, squarylium dyes, and formazan metal chelates that are particularly excellent in light resistance are desirable. Furthermore, other 3rd components, for example, a binder, a stabilizer, etc. can be contained as needed. The forming method includes a method in which an organic dye is developed in a solvent and applied by spin coating, and a method in which a film is formed by sputtering in a vacuum. The film thickness of the recording films 6 and 9 is usually 300 to 5000 mm, preferably 700 to 2000 mm. When the spin coating method is used, it is desirable to perform annealing at a high temperature in order to remove the residual solvent. The annealing temperature is usually preferably 80 to 110 ° C. Furthermore, the vicinity of 100 ° C. is preferable. The annealing time is preferably 15 minutes to 30 minutes.

In addition to the above organic materials, phase change materials can also be used in the case of the rewritable single-sided two-layer optical recording medium 1 conforming to the DVD + RW standard that can record information by changing the atomic arrangement. In this case, the recording films 6 and 9 include a film of a phase change material and a heat insulating protective film for holding heat of the phase change material. Specifically, it is an alloy represented by A—B—C—Ge—Te. Where A = Cu, Ag, Au, Sc, Y, Ti, Zr, V, Nb, Cr, Mo, Mn, Fe, Ru, Co, Rh, Ni, Pd, Hf, Ta, W, Ir, Pt, It represents at least one element among Hg, B, C, N, P, O, S, Se, a lanthanide element, an actinide element, an alkaline earth metal element, an inert gas element, and the like. B is at least one element among halogen elements such as Tl and I, and alkali metal elements such as Na. C is at least one element of Sb, SN, As, Pb, Bi, Zn, Cd, Si, Al, Ga, and In. Further, a metal material used for the magneto-optical material, for example, the metal elements Tb, Fe, Co, etc. can be used as the recording films 6 and 9. The protective film is made of the same or individual material. As each material, oxides such as SiO, SiO ₂ , ZnO, SNO ₂ , Al ₂ O ₃ , TiO ₂ , In ₂ O ₃ , MgO, ZrO ₂ , Si ₃ N ₄ , AlN, TiN, BN, ZrN, etc. Nitrides, sulfides such as ZnS, In ₂ S ₃ , TaS ₄ , carbides such as SiC, TaC, B ₄ C, WC, TiC, ZrC, diamond-like carbon, or a mixture of two or more of these . Further, as a forming method, sputtering, ion plating, vacuum vapor deposition, plasma CVD or the like is used later.

For the reflection films 7 and 8, for example, a silver film formed by sputtering is used. In addition, as the material of the reflection films 7 and 8, a metal material such as aluminum, silver, or copper, or an alloy material containing these as a main component can be used. It is particularly preferable to use a metal or alloy mainly composed of gold. When silver is the main component, the silver content is preferably 80 to 100 atomic%, particularly 90 to 100%. Of these reflective films 7 and 8, aluminum can be used because it is inexpensive and has been used in compact discs. When a metal material or an alloy material is used as the metal film material, the reflection films 7 and 8 can be formed by a vacuum film formation method such as sputtering or vacuum deposition. In this case, a technique for increasing the reflectance of the metal reflective film by changing the degree of vacuum in the vacuum chamber (for example, about 10 ⁻⁵ torr) and forming a film having a different density or crystallization state is applied. You can also As in the present embodiment, in the reflection films 7 and 8 having one or more recording layers at least in the back with respect to the incident direction of the recording / reproducing light, it is necessary to form a translucent reflection film in order to transmit the reflected light. Therefore, the thickness of the reflective films 7 and 8 is preferably 300 mm or more and 1000 mm or less.

  As the transparent substrates 3 and 5 serving as a base on which the recording films 6 and 9 are formed, a material that is transparent with respect to the wavelength of the recording / reproducing light is desirable. Examples include, but are not limited to, plastics such as polycarbonate, acrylic resin, polymethyl methacrylate, polystyrene resin, vinyl chloride resin, and epoxy resin, or glass. In particular, polycarbonate and acrylic resin are desirable due to ease of molding, inexpensive materials, and light weight differences. The recording film 6, 9 must be in front of the recording film 6, the reflective film 7, the recording film 9, and the reflective film 8 that form a pair with respect to the incident direction of the recording / reproducing light. Therefore, the order in which the recording film and the reflective film are laminated on the transparent substrates 2 and 5 is such that when the incident light reaches the recording layer through the transparent substrate, the transparent substrate 2, the recording film 6 and the reflective film 7 are laminated in this order. When reaching the recording layer without passing through the transparent substrate, it is desirable to laminate the transparent substrate 5, the reflective film 8, and the recording film 9 in this order.

  As a method of forming guide grooves (or guide pits = prepits) 11 and 12 serving as recording light guide tracks on the reflective films 7 and 8, guide grooves (or guide pits) 11 are formed on the transparent substrates 2 and 5. , 12 and the reflective films 7 and 8 formed thereon are preferable from the standpoint of manufacturing simplicity and cost. When the guide grooves (or guide pits) 11 and 12 are discriminated using the interference due to the path difference of the recording / reproducing light between the guide groove (or guide pits) 11 and 12 area and other areas, the depth is A depth of λ / 8n is optimal, where n is the refractive index of the transparent substrates 2 and 5, and λ is the wavelength of the recording light.

  The guide grooves (or guide pits) 11 and 12 for guiding the recording light guide the recording light to accurately scan the recording area on the optical recording medium 1, and the recording light defines the optical recording medium 1. It is common to have a synchronizing signal for scanning at a linear speed of. At this time, in order to generate a synchronization signal, a method of wobbling the guide grooves 11 and 12 at a constant period is generally used. Here, as in this embodiment, in order to record information such as recording conditions on the guide grooves (or guide pits) 11 and 12 for the recording light, the guide grooves (or guide pits) 11 and 12 are used. It is preferable to perform periodic modulation, amplitude modulation, phase modulation, etc. on the generated synchronization signal. In the case of the optical recording medium 1, since the intensity fluctuation of the reflected light varies greatly depending on the state of the optical recording medium 1, periodic modulation and phase modulation are preferable to amplitude modulation. Furthermore, phase modulation is suitable when the synchronization signal has a high period of 100 kHz, such as a DVD + R / RW type disc.

  As a method for producing a laminated structure of the recording films 6 and 9, a method in which the recording films 6 and 9 and the reflective films 7 and 8 are laminated on the transparent substrates 2 and 5 and the transparent substrates 2 and 5 are bonded together is preferable. As the adhesive film 10 at that time, a pressure sensitive adhesive sheet, a thermosetting adhesive, an ultraviolet curable adhesive, and a cationic ultraviolet curable adhesive are suitable. Furthermore, an adhesive sheet is particularly desirable from the viewpoint of smoothness and uniformity.

  In the multi-layered optical recording medium 1 having a plurality of recording layers 3 and 4 manufactured under such conditions, each recording layer 3 and 4 has an environment such as optical conditions and thermal conditions of incident recording light. Since the conditions are different, high quality recording cannot be performed under the same recording conditions. In this case, the “optical condition” refers to the recording layer (first recording layer 3) disposed in front of the recording layer (second recording layer 4) disposed behind the incident surface of the recording light. Intensity change due to passing, difference in optical path length due to passing through a plurality of transparent substrates 2, phase fluctuation due to birefringence of the transparent substrate 2, and the like. “Thermal condition” means that the recording films 3 and 4 are caused by the permutations and thickness differences of the reflecting films 7 and 8 near the recording films 6 and 9, the transparent substrates 2 and 5, and the adhesive film 10. Heat storage and heat dissipation conditions.

  High-quality recording can be performed on the plurality of recording layers 3 and 4 by selecting the optimum recording conditions for the recording layers 3 and 4 in consideration of the difference between these environmental conditions. The recording conditions at this time include the intensity, wavelength, phase, wavefront, and light emission waveform of the recording light. It is optimal to use the intensity condition and the light emission waveform condition that can be easily adjusted with a single light emitting element.

  As the contents of the recording conditions, the recording conditions are derived directly from the direct digitization of the intensity and waveform of the recording light, or from the trial writing on the optical recording medium 1 and the reflectance fluctuation of the optical recording medium 1. This is a setting condition. As a method for deriving the recording condition, a β method used for CD-R and DVD ± R and a γ method used for CD-RW and DVD ± RW are known as methods for deriving the intensity condition of recording light. In this case, the recording conditions include β and γ as targets, and an approximate recording intensity used for condition derivation. It is also possible to derive a suitable waveform condition by performing trial writing while changing the waveform condition. It is also possible to estimate the recording film thickness and the transmittance of the transparent substrate from the change in reflectance and derive a recording condition suitable for it. By using these methods for deriving the recording conditions, it is possible to cope with individual differences of the optical recording medium 1, and further, the amount of information recorded on the guide grooves (or induction pits) 11 and 12 as tracks as the recording conditions. Can be reduced.

  In the optical recording medium 1 having a plurality of recording layers 3 and 4, when trial writing is performed and the recording conditions are optimized, it is preferable to provide a trial writing area in each recording layer 3 and 4. Further, by performing test writing on all the recording layers 3 and 4 at the start of recording and optimizing the recording conditions, it is possible to reduce the time of test writing at the time of recording and perform continuous recording. However, the optical conditions such as the wavelength and efficiency of the light emitting element are fluctuated due to environmental fluctuations such as temperature during recording, and the recording conditions fluctuate between the optimization of the recording conditions and the actual recording. Therefore, the sensitivity of the recording films 6 and 9 due to changes in environmental conditions such as temperature is added to the recording conditions optimized at the start of recording by including information on sensitivity variations with respect to the wavelength and temperature of the recording films 6 and 9 in the recording conditions. By adding a condition calculated from fluctuations or the like, an optimum recording condition can be obtained for each of the recording layers 3 and 4 only by trial writing at the start of recording.

  The signal of the guide grooves (or induction pits) 11 and 12 as tracks changes before and after information is recorded on the recording layers 3 and 4, so that the signal SN changes on the optical recording medium 1. As a position for recording the recording conditions in the guide pits 11 and 12, a method in which the user avoids a data area in which arbitrary information is recorded is preferable. When the guide grooves (or guide pits) 11 and 12 are arranged concentrically or spirally, a data area is often provided in the middle area, so that recording conditions are set on at least one of the inner and outer circumferences. It is preferable to record.

  Further, when the guide grooves (or induction pits) 11 and 12 are arranged in a spiral shape, the entire surface of the optical recording medium 1 can be continuously scanned by rotating the optical recording medium 1 during recording and reproduction. In this case, in order to avoid unnecessary movement of the optical pickup at the start of recording, the inner peripheral portion or the outer peripheral portion where recording is started, and when the spiral direction is toward the outer periphery with respect to the rotational direction at the time of recording / reproducing of the optical recording medium 1, When going to the inner periphery, it is preferable to have recording conditions on the outer periphery.

  Further, by determining the recording condition by performing trial writing on the optical recording medium 1, it is possible to derive a suitable recording condition in consideration of environmental conditions such as temperature and humidity. Also in this case, in order to obtain good recording quality at the start of recording, the inner peripheral portion or the outer peripheral portion where recording is started, or the inner peripheral portion when the spiral direction is toward the outer periphery with respect to the rotation direction during recording / reproducing of the optical recording medium 1 In addition, when going to the inner circumference, it is preferable to have a test writing area on the outer circumference. In this case, unnecessary movement of the optical pickup can be omitted, and the time from trial writing to recording can be shortened to suppress the change over time in suitable recording conditions.

  As a method for recording the recording conditions on the recording layers 3 and 4, there is a method of recording the recording conditions of the same specification on the recording layers 3 and 4. In this case, since it is possible to set the recording conditions and / or to derive the recording conditions for each of the recording layers 3 and 4, the recording conditions can be expanded without changing the format of the recording conditions for the subsequent increase in the number of recording layers. can do. Therefore, it can be easily applied to an optical recording medium that is already widely used as an optical recording medium having a single recording layer, such as DVD ± R / RW and CD-R / RW.

  Further, as a recording method of the recording conditions on each recording layer 3, 4, the recording conditions are recorded on the recording layer that performs recording first (that is, the first recording layer 3) among the recording layers 3, 4, In addition, the recording layer 3 includes a reflective film 7 paired with information for identifying the recording layer 3, and for the other recording layers 4, the recording conditions for the recording layer 4 are derived from the recording conditions of the first recording layer 3. There is a method of recording the information. This method can reduce the amount of information necessary for the recording conditions for the recording layers after the second recording layer 4 as compared with the recording method described above. Therefore, if the error correction capability is improved by adding a surplus signal, sufficient reading capability can be maintained even if the signal-to-noise ratio of the signal is reduced by recording the first recording layer 3.

  Further, as a recording method of recording conditions on each recording layer 3, 4, there is a method of recording the recording conditions of all the recording layers 3, 4 on the first recording layer 3. In this case, compatibility with a single recording layer is difficult to maintain, but since it is not necessary to read the recording conditions after the second recording layer 4, the second recording layer 4 and the subsequent recording signals of the recording layer 4 are identified. Signal quality that can only be read out is sufficient. The first recording layer 3 that performs recording first is desirably the recording layer that is closest to the recording light incident surface that can be read without being subjected to factors such as the other recording layer 4. Or, conversely, the first recording layer 3 that performs the recording first may be the recording layer that is located on the farthest side as viewed from the recording light incident side. That is, if the first recording layer 3 that performs the recording first is the recording layer that is located farthest from the incident surface side of the recording light, the first recording layer 3 is recorded at the time of recording on the second recording layer on the front side. Since recording can be performed without being affected by the preceding recording layer including one recording layer, stable recording can be performed.

  Further, in the case of the optical recording medium 1 having a plurality of recording layers 3 and 4, accumulation of heat generation in the recording apparatus is performed when the recording layers 3 and 4 are continuously recorded and when all the recording layers 3 and 4 are continuous. Environmental conditions such as temperature vary greatly because the amount changes. In particular, when a semiconductor laser is used as a light source, wavelength variation due to temperature is significant. Therefore, it is desirable to provide a recording condition on the optical recording medium 1 that varies in recording conditions depending on temperature and wavelength. As a result, suitable recording can be performed no matter where the optical recording medium 1 starts to be recorded.

[Example of signal format configuration]
Specific configuration examples (signal format examples) of the present embodiment based on the above-described various configuration examples will be described as configuration examples 1 to 4 with reference to FIGS.

  2 to 5 schematically show examples of signal formats recorded on the recording guide grooves (tracks) 11 and 12 of the configuration examples 1 to 4. FIG. FIG. 6 is a comparative example showing an example of a single layer structure. In these drawings, “corresponding standard information” refers to a corresponding standard version of the optical recording medium 1. “Disk structure” means physical shape information such as the size of the optical recording medium 1, track pitch of the guide grooves 11 and 12, recording film material, data area start address, end address information, optical recording medium 1 Information such as the purpose of use. The “recording layer number” is layer information used for identifying the recording layers 3 and 4 by entering different values for the recording layers 3 and 4 respectively. “Vendor information” and “version information” are vendor information (maker identification information) of the optical recording medium 1 and manufacturing version information of the optical recording medium 1. The “wavelength condition” represents the sensitivity fluctuation of the recording film depending on the wavelength.

[Configuration example 1]
In the configuration example 1 shown in FIG. 2, both the first recording layer 3 and the second recording layer 4 have a parallel track path (PTP) type light having spiral guide grooves 11 and 12 from the inner circumference side to the outer circumference side of the medium. 2 is an example of a recording medium 1. In this example, information relating to recording conditions and layer information are preformatted on the inner periphery of each of the first recording layer 3 and the second recording layer 4 on the guide grooves 11 and 12.

  Therefore, for the first recording layer 3, trial writing is performed on the first recording layer 3 using the recording conditions pre-formatted on the guide grooves 11 of the first recording layer 3, and the optimum recording conditions are derived. In addition, direct recording is performed according to direct recording conditions. When recording on the second recording layer 4, the optical pickup moves to the inner periphery of the optical recording medium 1, and the recording conditions preformatted on the guide groove 11 of the second recording layer 4 are used. Test writing is performed to derive optimum recording conditions, and direct recording is performed according to the direct recording conditions. Therefore, by using such an optical recording medium 1, recording can be performed on each recording layer 3, 4 based on optimum recording conditions.

[Configuration example 2]
In the configuration example 1 shown in FIG. 3, the first recording layer 3 has a spiral guide groove 11 from the medium inner circumferential side to the outer circumferential side, but the second recording layer 4 is directed from the medium outer circumferential side to the inner circumferential side. 2 is an example of an opposite track path (OTP) type optical recording medium 1 having a spiral guide groove 12. In this example, information on the recording conditions and layer information are preformatted on the inner circumferential portion on the guide groove 11 of the first recording layer 3, and information on the outer circumferential portion is recorded on the guide groove 12 of the second recording layer 4. An example in which information and layer information are preformatted is shown.

  Therefore, for the first recording layer 3, as in the case of the configuration example 1, using the recording conditions on the first recording layer 3, trial writing is performed on the first recording layer 3 to derive optimum recording conditions. In addition, direct recording is performed according to direct recording conditions. Subsequently, when recording on the second recording layer 4, test writing is performed on the outer periphery of the second recording layer 4 using the recording conditions on the second recording layer 4 with an optical pickup that extends to the outer periphery. Recording conditions are derived, and direct recording is performed according to the direct recording conditions.

  Therefore, by using such an optical recording medium 1, the movement of the optical pickup from the first recording layer 3 to the second recording layer 4 becomes the shortest, so that substantially continuous recording is possible and each recording is possible. Recording can be performed in the layers 3 and 4 based on optimum recording conditions. Further, the signal format recorded in the guide groove 11 of the first recording layer 3 is almost the same as that of the single-layer recording layer of Comparative Example 1 shown in FIG. 6 and has high backward compatibility as the optical recording medium 1. It becomes.

[Configuration example 3]
Configuration example 3 shown in FIG. 4 is an example of an opposite track path (OTP) type optical recording medium 1 similar to the case of configuration example 2. However, unlike the configuration example 2, the guidance of the second recording layer 4 is performed. On the groove 12, information on the recording condition of the second recording layer 4 includes indirect recording conditions for deriving the recording conditions for the second recording layer 4 from the recording conditions of the first recording layer 3. Information is recorded, and the amount of information necessary for the recording condition is smaller than that in the configuration example 2.

  Therefore, for the first recording layer 3, test writing is performed on the first recording layer 3 using the recording conditions on the first recording layer 3 in the same manner as in the configuration examples 1 and 2, and the optimum recording conditions are set. Derived and recorded directly according to the direct recording conditions. Subsequently, when recording on the second recording layer 4, test writing is performed on the outer periphery of the second recording layer 4 using the recording conditions on the second recording layer 4 with an optical pickup that extends to the outer periphery. The recording condition is derived, and the recording condition for the second recording layer 4 is derived according to the derived information based on the recording condition of the first recording layer 3, and recording is performed according to the condition.

  Therefore, by using such an optical recording medium 1, the movement of the optical pickup from the first recording layer 3 to the second recording layer 4 becomes the shortest, so that substantially continuous recording is possible and each recording is possible. Recording can be performed in the layers 3 and 4 based on optimum recording conditions. Further, the signal format recorded in the guide groove 11 of the first recording layer 3 is almost the same as that of the single-layer recording layer of Comparative Example 1 shown in FIG. 6 and has high backward compatibility as the optical recording medium 1. It becomes. Furthermore, since only the conditions for changing the recording conditions of the second recording layer 4 from those of the first recording layer 3 are used, the amount of information necessary for the recording conditions can be reduced.

[Configuration Example 4]
Configuration example 4 shown in FIG. 5 is an example of an opposite track path (OTP) type optical recording medium 1 similar to the case of configuration examples 2 and 3, but unlike the case of configuration examples 2 and 3, it relates to recording conditions. All the information is recorded on the guide groove 11 of the first recording layer 3, and only the layer information is recorded on each of the recording layers 3 and 4.

  Therefore, for the first recording layer 3, test writing is performed on the first recording layer 3 using the recording conditions on the first recording layer 3 in the same manner as in the configuration examples 1 to 3, and the optimum recording conditions are set. Derived and recorded directly according to the direct recording conditions. Subsequently, when recording on the second recording layer 4, only the layer information on the second recording layer 4 is recognized by the optical pickup extending to the outer peripheral portion, and the recording conditions are the second recording acquired in the first recording layer 3. Using the recording conditions for the layer 4, trial writing is performed on the outer periphery of the second recording layer 4, the optimum recording conditions are derived, and recording is performed according to the recording conditions.

  Therefore, by using such an optical recording medium 1, the movement of the optical pickup from the first recording layer 3 to the second recording layer 4 becomes the shortest, so that substantially continuous recording is possible and each recording is possible. Recording can be performed in the layers 3 and 4 based on optimum recording conditions. Further, since the recording conditions of the second recording layer 4 are recorded in the first recording layer 3, it is possible to recognize only the layer information for identifying the second recording layer 4.

[Information recording method]
Therefore, as an information recording method when the optical recording medium 1 of the present invention as exemplified in these structural examples 1 to 4 is loaded in the optical information recording apparatus, the process shown in FIG. Take it. First, the presence or absence of loading of the optical recording medium 1 is monitored (step S1), and if loaded, prior to the recording operation on the optical recording medium 1, the recording conditions are related from the guide grooves 11 and 12 of the optical recording medium 1. The information and the layer information for identifying the recording layers 3 and 4 are read (S2: Condition reading step. Subsequently, the recording to be recorded is performed based on the information related to the read recording conditions and the layer information for identifying the recording layers 3 and 4. Recording conditions for the layer 3 or 4 are set (S3; recording condition setting step), and a recording operation for the recording layer 3 or 4 to be recorded is executed according to the set recording conditions (S4; recording operation execution step). ).

  As described above, according to the present embodiment, even in the case of the multilayered optical recording medium 1 having the plurality of recording layers 3 and 4, information on the recording conditions provided as information on the guide grooves 11 and 12 and each By reading the layer information for identifying the recording layer, setting the recording condition for the recording layer 3 or 4 and executing the recording operation, optimum recording can be performed under the recording condition suitable for each recording layer 3 and 4. Can do.

[Modification]
In the above description, when recording on the recording layers 3 and 4 having a multi-layer structure, as a track, the recording tracks 3 and 4 are normally only on the grooves (guide grooves 11 and 12). Although described as an example of application to a recording system (recording only on lands, or recording on both grooves and lands), a multilayered recording layer is an odd-numbered layer. The present invention can be similarly applied to an optical recording medium in which groove tracks and land tracks are alternately set as the recording positions in the even-numbered layers. For example, the first recording layer and its wobble are conventionally arranged on the groove track (guide groove), but the second recording layer and its wobble are arranged on the land track as in the conventional method. This is because when recording is performed on the second recording layer of a two-layer disc in which an organic dye-based material is mainly used, it is necessary to mark the second recording layer deeply in a layer direction. If the mark is formed on the groove of the second recording layer, the heat at the time of recording is transferred to the land side, and the recording quality is deteriorated. This is a track system to avoid.

  The track system will be described with reference to FIG. First, the first recording layer 3 has a recording film 6 having a groove structure in the laser irradiation direction with respect to the reflective layer 7, and the second recording layer 4 also has a groove structure in the laser irradiation direction with respect to the reflective layer 8. A film 9 is formed. The groove is formed in a spiral shape from the center direction of the disc toward the outer periphery, and the information recording / reproducing apparatus performs reproduction and recording along the groove. In general, the groove closer to the laser irradiation surface side is called a groove track 11, and the far groove is called a land track 13. In the first recording layer 3, a recording film 6 is formed on the groove track 11. In the two recording layer 4, a recording film 9 is formed on the land track 13. In other words, the first recording layer 3 and the second recording layer 4 have recording films formed on different tracks.

  More specifically, in the groove structure of the first recording layer 3, the groove track 11 is formed by the recording film 6. As shown in FIG. 9A, the groove track 11 is wobbled, and the wobble signal records position information in the disk surface, recording power and recording pulse shape when performing OPC, and the like. Has been. A second recording layer 4 is formed in the back of the first recording layer 3 with the adhesive layer 10 and the inorganic protective layer 14 interposed therebetween. Unlike the first recording layer 3, the second recording layer 4 has a recording film 9 formed on the land track 13, and a wobble signal is also recorded on the land track 13 (see FIG. 9B). In this wobble signal, the position information of the second recording layer 4, the recording power and the recording pulse shape when performing OPC, and the like are recorded.

  Even in the case of an optical disc employing such a track system, the recording method of the recording conditions on the recording layers 3 and 4 as described with reference to FIGS.

1 is a cross-sectional structure diagram of an optical recording medium showing an embodiment of the present invention. It is a schematic diagram which shows the example of a signal format on a guide groove in the case of the structural example 1. FIG. It is a schematic diagram which shows the example of a signal format on a guide groove in the case of the structural example 2. FIG. It is a schematic diagram which shows the example of a signal format on a guide groove in the case of the structural example 3. FIG. It is a schematic diagram which shows the example of a signal format on a guide groove in the case of the structural example 4. It is a schematic diagram which shows the example of a signal format on a guide groove in the case of a comparative example. It is a schematic flowchart which shows the information recording method. FIG. 10 is a cross-sectional structure diagram of an optical recording medium showing a modified example of a different track system. It is explanatory drawing which shows typically the example of the wobble signal on each track.

Explanation of symbols

1 optical recording medium 3 first recording layer 4 second recording layer 11, 12 tracks

Claims (13)

An optical recording medium having a multilayer recording layer of an opposite track path system each having a spiral track for guiding recording light, and capable of recording data on each recording layer,
The test writing area to be trial-written to determine the recording conditions for recording data on each recording layer is set to at least the inner circumference when the spiral direction of the track is directed from the inner circumference side to the outer circumference side during recording / reproduction. Has at least the outer peripheral part when going from the outer peripheral side to the inner peripheral side,
The layer information for identifying each recording layer has at least the inner peripheral portion when the spiral direction of the track goes from the inner peripheral side to the outer peripheral side at the time of recording / reproduction, and the information goes from the outer peripheral side to the inner peripheral side An optical recording medium having at least an outer peripheral portion.   2. The optical recording medium according to claim 1, wherein layer information for identifying each recording layer is preformatted on the track itself.   3. The optical recording medium according to claim 2, wherein the recording layer of the multilayer structure has an odd numbered layer and an even numbered layer in which groove tracks and land tracks are alternately set as recording positions.   4. The optical recording medium according to claim 2, wherein layer information for identifying each recording layer is preformatted as pits or grooves constituting the track.   5. The optical recording medium according to claim 2, wherein layer information for identifying each recording layer is preformatted on the track itself by phase modulation.   6. The optical recording medium according to claim 1, wherein layer information for identifying each recording layer is provided on the track outside the data area.   The optical recording medium according to claim 1, wherein each recording layer individually includes layer information for identifying each recording layer.   The optical recording medium according to any one of claims 1 to 7, wherein the recording layer to be recorded first is positioned closest to the recording light incident side.   The optical recording medium according to any one of claims 1 to 7, wherein the recording layer to be recorded first is located on the innermost side when viewed from the incident side of the recording light.   10. The optical recording according to claim 1, wherein each recording layer is transparent with respect to a wavelength of the recording light, and is laminated on a substrate on which a track is formed. Medium.   11. The optical recording medium according to claim 1, wherein the optical recording medium conforms to a DVD + R standard and has the two recording layers on one side.   11. The optical recording medium according to claim 1, wherein the optical recording medium conforms to a DVD + RW standard and has two recording layers on one side. Recording data on one of the recording layers of the optical recording medium according to any one of claims 1 to 12,
A step of performing test writing in the test writing area of a recording layer adjacent to the recording layer in which the data is recorded, and determining the recording conditions;
An information recording method comprising: recording data on the adjacent recording layer under the determined recording condition.

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