WO2005069284A1 - Information recording medium - Google Patents

Abstract

An information recording medium comprises first and second recording layers (107, 207) for recording information. The first and second recording layers each have a groove track (GT) having the same track pitch and adapted to record the information and are preformatted (109, LPP) for producing a clock used in recording so that the recording densities of the recorded information in the layers are different.

Description

 Specification

 Information recording medium

 Technical field

 The present invention relates to a technical field of an information recording medium such as a CD and a DVD.

 Background art

 [0002] For example, information recording media such as optical discs such as CD-ROMs (Compact Disc-Read Only Memory), CD-Rs (Compact Disc-Recordable), and DVD-ROMs are disclosed in Patent Document 1 and the like. In addition, a multi-layer or double-layer or multiple-layer optical disc in which a plurality of recording layers are laminated on the same substrate has been developed. More specifically, the two-layer type optical disk is firstly located on the most front side (that is, the side close to the optical pickup) when viewed from the laser light irradiation side when recording by the information recording device. It has a first recording layer (referred to as an “L0 layer” as appropriate in the present application), and further has a semi-transmissive reflective film located on its inner side (ie, farther from the optical pickup). As a second layer, a second recording layer (referred to as “L1 layer” in the present application) located on the back side of the transflective film with an intermediate layer such as an adhesive layer interposed therebetween is further provided. A reflective film located on the side. When creating such a multi-layer information recording medium, the L0 layer and the L1 layer are formed separately, and finally, the respective layers are bonded together, so that the single-sided, dual-layer optical disc can be manufactured at low cost. Can be manufactured.

 [0003] In an information recording apparatus such as a CD recorder for recording information on such a single-sided, dual-layer optical disc, a recording laser beam is focused (or irradiated) on the L0 layer. Then, information is recorded on the L0 layer by an irreversible change recording method such as irreversible change recording heating and rewritable method, and the laser beam is condensed on the L1 layer. Information is recorded in an irreversible change recording method using irreversible change recording heating or in a rewritable method.

[0004] Furthermore, the recording density of each recording layer is set so as to decrease as the distance from the reference plane parallel to the recording layer increases, so that the signal recorded on each layer can be reproduced correctly. A single-sided-layer type optical disc is described in Patent Document 2, and furthermore, a cover sheet side Patented single-layer, single-layer optical disc for recording, in which the track pitch of the recording layer (LI layer) is wider than the track pitch of the recording layer (LO layer) on the substrate side so that stable tracking can be obtained even for eccentricity. It is described in Reference 3!

Patent Document 1: JP 2001-23237 A

 Patent Document 2: Japanese Patent Application Laid-Open No. 11-16207

 Patent Document 3: JP-A-2003-141775

 Disclosure of the invention

 Problems to be solved by the invention

 [0006] In a general single-sided, dual-layer information recording medium (eg, DVD-ROM), information is recorded such that the recording densities of the L0 layer and the L1 layer are equal to each other due to the standard. Is done. For this reason, information is recorded so as to have a predetermined recording density even when there is a margin in the recording capacity in each recording layer. More specifically, even if there is room for increasing the recording density in each recording layer, the recording density is forcibly reduced to equalize the recording densities of the respective recording layers. Alternatively, even if there is no margin in the margin of information to be recorded due to the condensing of the laser beam or the like, it is necessary to leave a margin without margin to equalize the recording densities of the respective recording layers. Data is recorded. As described above, the current information recording medium is inefficient from the viewpoint of recording density, and information is not necessarily recorded in an optimal state even in each recording layer. It has technical problems.

 [0007] In order to solve this technical problem, Patent Documents 2 and 3 have a problem that the characteristics of the force tracking error signal, which is an approach of increasing the track pitch, are different in each layer.

 [0008] An object of the present invention is to provide a multi-layer information recording medium, for example, in view of the above-mentioned conventional problems.

 Means for solving the problem

[0009] In order to solve the above problems, an information recording medium of the present invention includes at least a first recording layer and a second recording layer for recording information, and the first recording layer and the second recording layer Each of the recording layers has the same track pitch force and has a groove track for recording the information, and the recording density at the time of recording is different so that the recording density of the information recorded on each recording layer is different. A preformat for generating a clock has been performed.

 [0010] The operation and the advantages of the present invention will be made clear by the embodiment described below.

 Brief Description of Drawings

 FIG. 1 shows the basic structure of an optical disc according to a first embodiment of the information recording medium of the present invention, and the upper part is a schematic plan view of the optical disc having a plurality of recording areas, and is associated with this. The lower part is a schematic conceptual diagram of the recording area structure in the radial direction.

 FIG. 2 is a partially enlarged perspective view of a recording surface of the optical disc according to the first embodiment of the present invention.

FIG. 3 is a schematic diagram conceptually showing information pits recorded on groove tracks of the optical disc according to the first embodiment.

 FIG. 4 is a plan view conceptually showing the distribution of the recording density of the optical disc according to the second embodiment.

 FIG. 5 is an explanatory diagram conceptually showing a mode of recording information on a recording layer farther from the side irradiated with the laser beam, of two different recording layers of the optical disc according to the second embodiment. is there.

 FIG. 6 is a block diagram of an information recording / reproducing apparatus according to an embodiment of the present invention.

 Explanation of symbols

[0012] 1 Center Honoré

 100, 100a, 100b, 100c Optical disc

 102 data zone

 109 wobbles

 300 Information recording / reproducing device

 306 Data input / output control means

 307 Operation control means

 352 Optical pickup

 353 Signal recording / reproducing means

 354 Processor (drive control means)

 GT Groove Truck

LT Land Truck LB laser light

 LPP Land Prepit

 BEST MODE FOR CARRYING OUT THE INVENTION

 [0013] An embodiment of the information recording medium of the present invention includes at least a first recording layer and a second recording layer for recording information, and the first recording layer and the second recording layer are respectively provided. The same track pitch force has a groove track for recording the information, and generates a recording clock so that the recording density of the information recorded on each recording layer is different. Preformatted.

 According to the embodiment of the information recording medium of the present invention, information can be recorded on each of the first recording layer and the second recording layer. Each recording layer has a group track for recording information, and the track pitch, which is the interval between these group tracks, is the same in each recording layer.

 [0015] In the present embodiment, in particular, the preformat is performed such that the information recording density of the first recording layer is different from the information recording density of the second recording layer. Various types of information are recorded based on a recording clock (clock at the time of recording) generated based on the preformat, for example, by the operation of an information recording / reproducing apparatus described later. For example, if the recording density of the first recording layer is higher than the recording density of the second recording layer, the first recording layer contains information having a capacity equal to or greater than the information recordable on the second recording layer having the same area. Can be recorded. On the other hand, for example, if the recording density of the first recording layer is lower than the recording density of the second recording layer, the first recording layer has information having a capacity larger than the information recordable on the second recording layer of the same area. Cannot be recorded.

 If it is assumed that the recording densities of the first recording layer and the second recording layer must be the same, the optimum of each recording layer (that is, the first recording layer and the second recording layer) If the recording densities are the same, it is good, but if they are not (ie, the optimum recording densities of the respective recording layers are different), inconvenience occurs. In this case, it is necessary to forcibly match the recording density of one recording layer with the recording density of the other recording layer, and information is not always recorded at the optimum recording density in the other recording layer. Problems.

However, according to the present embodiment, the recording densities of the respective recording layers are different from each other (ie, Since the preformat is performed (so that information can be recorded at different recording densities on the respective recording layers), the above-described inconvenience does not occur. That is, it is not always necessary to make the recording densities of one recording layer and the other recording layer coincide. Therefore, regardless of the recording density and the state of the other recording layer, information can be recorded on one recording layer at a suitable or optimum recording density. For example, the recording density of the second recording layer can be determined regardless of the recording density of the first recording layer, and the recording density of the first recording layer can be determined regardless of the recording density of the second recording layer. it can. Further, it is not necessary to forcibly adjust the recording density, and as a result, the disadvantage that information is recorded in an originally undesirable state can be solved. This has a great advantage that it leads to improvement in information recording characteristics (for example, stable recording).

 As a result, according to the embodiment of the information recording medium of the present invention, since the recording densities of the first recording layer and the second recording layer are different, each recording layer has! Information can be appropriately recorded at a suitable recording density.

 [0019] In one aspect of the embodiment of the information recording medium of the present invention, the first recording layer and the second recording layer each include a groove track that oscillates at a different cycle in each recording layer. The preformat has been performed.

 According to this aspect, the groove track oscillates at a predetermined cycle, and has a wobble (or wobble). This page is mainly used as one parameter for generating a reference clock indicating the recording timing when information is recorded on the information recording medium. Then, since the period of the swing (that is, the wobble) of the groove track is different in each of the first recording layer and the second recording layer, the information recording density in each recording layer can be made different. In other words, even for information recording media having different recording densities, an appropriate recording operation can be realized by referring to the reference clock indicated by the oscillation cycle.

[0021] In another aspect of the embodiment of the information recording medium of the present invention, the first recording layer and the second recording layer each further include a land pre-pit indicating a recording address position on the groove track. The land prepits in each recording layer are formed such that the recording densities of the information recorded in each recording layer are different. According to this aspect, the recording address position on the group track indicated by the land pre-pit (for example, LPP described later) is different in each of the first recording layer and the second recording layer. The recording density of information in the recording layer can be different. In other words, even with information recording media having different recording densities, an appropriate recording operation can be realized by referring to the land pre-pits.

 [0023] In another aspect of the embodiment of the information recording medium of the present invention, the first recording layer and the second recording layer each have a minimum reproduction jitter of the information recorded on each recording layer. In addition, the preformat is performed.

 According to this aspect, the recording density of the first recording layer is defined as a value that minimizes the reproduction jitter value of information recorded on the first recording layer, and the recording density of the second recording layer is It is defined as a value that minimizes the reproduction jitter value of the information recorded on the two recording layers. Therefore, there is a great advantage that it is possible to more appropriately reproduce information in each of the recording layers in addition to the various benefits described above.

 [0025] The operation and other advantages of the present embodiment will become more apparent from the examples described below.

 As described above, according to the embodiment of the information recording medium of the present invention, the preformat is performed so that the recording densities of the first recording layer and the second recording layer are different from each other. Therefore, information can be appropriately recorded at a more suitable recording density in each recording layer.

 Example

(Information recording medium)

 Hereinafter, embodiments of the information recording medium of the present invention will be described with reference to the drawings.

(First Example)

 First, an optical disc according to a first embodiment of the information recording medium of the present invention will be described in detail with reference to FIGS.

First, the basic structure of the optical disc according to the first embodiment will be described with reference to FIG.

Here, FIG. 1 shows a basic structure of an optical disc according to a first embodiment of the information recording medium of the present invention, and an upper part is a schematic plan view of an optical disc having a plurality of recording areas. The lower portion associated therewith is a schematic conceptual diagram of the recording area structure in the radial direction.

 As shown in FIG. 1, the optical disc 100 is, for example, on a recording surface on a disc body having a diameter of about 12 cm, which is the same as a DVD, with the center hole 1 as the center and the inner peripheral force directed toward the outer peripheral side. A lead-in area 101, a data zone 102, and a lead-out area 103 according to the example are provided. In each recording area, for example, tracks 10 such as groove tracks and land tracks are alternately provided spirally or concentrically with the center hole 1 as a center. On the track 10, data is recorded by being divided into units of sectors 11. The sector 11 is a data management unit based on a preformat address in which recording information can be corrected for errors.

 The present invention is not particularly limited to an optical disk having such three areas.

 For example, even if the lead-in area 101 and the lead-out area 103 do not exist, the data structure described below can be constructed. Further, as described later, the lead-in area 101 and the lead-out area 103 may have a configuration further subdivided.

 As shown in FIG. 2, the optical disc 100 according to the first embodiment is configured as a two-layer optical disc in which a plurality of data zones 102 and the like are formed in a laminated structure, for example. FIG. 2 is a partially enlarged perspective view of the recording surface of the optical disc of the first embodiment.

 In FIG. 2, in the first embodiment, the optical disc 100 is placed on a disc-shaped transparent substrate 106.

(On the lower side in FIG. 2), an irreversible change recording due to heating or the like constituting the information recording surface, and a first recording layer 107 (that is, an LO layer) of an irreversible change recording type by heating and the like are further laminated thereon. On the lower side (in FIG. 2), a transflective film 108 is laminated. On the information recording surface composed of the surface of the first recording layer 107, groove tracks GT and land tracks LT are formed alternately. At the time of recording and reproduction of the optical disc 100, for example, as shown in FIG. 2, the laser beam LB is irradiated onto the groove track GT via the transparent substrate 106. For example, at the time of recording, irreversible change recording is performed by heating the first recording layer 107 according to the recording data by irradiating the laser beam LB with the recording laser power. On the other hand, at the time of reproduction, the recording data written in the first recording layer 107 is read by irradiating the laser beam LB with the reproduction laser power weaker than the recording laser power. [0034] In the present embodiment, the groove track GT is rocked at a constant amplitude and a constant spatial frequency. That is, the groove track GT is wobbled, and the cycle of the wobbles 109 is set to a predetermined value. On the land track LT, an address pit called a land pre-pit LPP indicating a recording address position (pre-format address information) on the groove track is formed. Information necessary for data recording, such as generation of a disk rotation control signal and a recording clock during recording and a recording address on the groove track GT, can be obtained by these two addressing (that is, the page 109 and the land pre-pit LPP). The preformat address information may be recorded in advance by modulating the wobble 109 of the groove track GT by a predetermined modulation method such as frequency modulation or phase modulation.

 Further, in this embodiment, the second recording layer 207 (ie, L1 layer) is formed on the transflective film 108 (the lower side in FIG. 2), and further thereon (the lower side in FIG. 2). A reflection film 208 is formed. The reflection film 208 is formed on the second recording layer 207. The second recording layer 207 is irradiated with the laser beam LB through the transparent substrate 106, the first recording layer 107, and the semi-transmissive reflection film 108, and thus, in a manner similar to the first recording layer 107, irreversible by heating or the like. It is configured to enable change recording type recording and playback. The second recording layer 207 and the reflection film 208 may be formed on the transparent substrate 106 on which the first recording layer 107 and the transflective film 108 are formed, or may be formed on another substrate. After forming the film, it may be bonded to the transparent substrate 106. A transparent intermediate layer 205 having a strength such as a transparent adhesive is provided between the transflective film 108 and the second recording layer 207 as appropriate according to the manufacturing method.

 At the time of recording / reproducing of such a two-layer type optical disc 100, recording / reproducing on the first recording layer 107 is performed or the recording / reproducing is performed on the first recording layer 107, depending on which recording layer is focused on the laser beam LB. Recording and reproduction on the two recording layers 207 are performed.

 The optical disc 100 according to the first embodiment may be a multi-layer optical disc having three or more layers, as shown in FIG. 2, which is not limited to a two-layer single-sided, that is, a dual layer. . If the optical disc has three or more layers, a semi-transmissive reflective film is provided in place of the reflective film 208, and a third recording layer and a reflective film (or a semi-transmissive reflective film) are further provided thereon (the lower side in FIG. 2). May be formed in order.

Subsequently, information pits recorded on the recording layer of the optical disc 100 will be described with reference to FIG. This will be described in more detail. FIG. 3 is a schematic view conceptually showing information pits recorded on a groove track.

 As shown in FIG. 3, recording data including video information, audio information, and the like is recorded on the first recording layer and the second recording layer as information pits. For these information pits, for example, an ECC as an error correction code is added to the coded or compressed original video information or audio information and the like, and a modulation signal is created by performing 8Z16 modulation. After that, it is recorded on the groove track GT so as to have a pit length corresponding to the modulation signal.

 In the first embodiment, particularly, the LO layer shown on the left side in FIG. 3 and the L1 layer shown on the right side in FIG. 3 are formed such that the swing cycle of the double track GT is different. As a result, by performing the recording operation based on the recording clock defined by the magnitude of the oscillation cycle, the unit length of the information pits recorded on each recording layer becomes different. That is, when the same recording data is recorded in each of the LO layer and the L1 layer, it is recorded as information pits having different pit lengths. Specifically, it is assumed that predetermined information pits are recorded in the LO layer as shown in the left-hand diagram in FIG. At this time, when the same recording data as the recording data recorded on the LO layer is recorded on the L1 layer, information pits shorter than the information pits on the LO layer are generated as shown in the right diagram in FIG. Be recorded. In other words, the five information pits on the left side in FIG. 3 and the five information pits on the right side in FIG. The recording densities will be different.

As described above, by changing the oscillation period of the groove track GT so that the unit length of the information pits of the LO layer and the L1 layer (ie, the recording density) changes, the recording density of each recording layer is changed. Can be different. For example, in Fig. 3, the unit length of the information pits recorded in the L1 layer is shorter than the unit length of the information pits recorded in the LO layer, so the recording density in the L1 layer is Large compared to. At this time, for example, assuming that the channel bit rate of the information recording / reproducing apparatus described later is the same in the LO layer and the L1 layer, the linear velocity of the LO layer is relatively high in order to properly record data. However, the linear velocity of the L1 layer needs to be relatively low. At this time, the period of the wobbles 109 is changed in accordance with the change in the unit length of the information pit (or in accordance with the change in the recording density). ing. As a result, even if the unit length of the information pit is changed, the information recording / reproducing apparatus described below can appropriately record information by referring to the preformat address information that has been changed accordingly. It becomes possible. In other words, if the optical disc has the preformat address information changed in this way, for example, the information recording / reproducing apparatus refers to the table 109 or the like and records the recorded data with the length of the information pit corresponding to the information. Can be recorded.

 Further, as shown in FIG. 3, the position of the land prepit LPP indicating the preformat address information has also been changed. Specifically, according to the fact that the period of the pebbles 109 of the L1 layer is smaller than that of the LO layer, the interval between the land prepits LPP in the L1 layer is smaller than that of the LO layer. Also according to this, for example, the information recording / reproducing apparatus can record the recording data with the information pit length corresponding to the land pre-pit LPP.

 [0043] It is preferable that the recording density in each recording layer is an optimum recording density for each recording layer. More specifically, for example, the recording density may be such that the reproduction jitter value when reproducing the information pit is minimized. That is, the recording density in the LO layer may be such that the reproduction jitter value when reproducing the information pits recorded in the LO layer is minimized, and the recording density in the L1 layer is the L1 layer. The recording density may be such that the reproduction jitter value at the time of reproducing the information pits recorded on the disc is minimized. In any case, the recording density of the LO layer can be determined regardless of the recording density of the L1 layer, and the recording density of the L1 layer can be determined regardless of the recording density of the LO layer. Further, the recording density may be such that the reproduction error rate is minimized, or the recording density may be such that there is a margin (interval) enough to track information pits.

 As a result, according to the optical disc 100 of the first embodiment, recording data can be recorded at an optimum recording density for each recording layer. Further, according to the recording density of the other recording layers, it is not necessary to record the recording data in an originally undesired state. As a result, the characteristics of the recording data are improved and the advantages are obtained.

In the first embodiment, the tape 109 and the land pre-pit LPP are used to record the pre-format address information. RZRW, etc.). For example, in the case of a DV D + RZRW or the like as a specific example of an optical disk, since the preformat address information is recorded by the wobbles 109 without using the land prepit LPP, it is sufficient to change the cycle of the wobbles 109. You. In various other optical discs as well, if the preformat address information is recorded so that the recording density of data is different in each recording layer, the above-mentioned various benefits can be enjoyed.

(Second Embodiment)

 Next, an optical disc according to a second embodiment of the information recording medium of the present invention will be described with reference to FIGS. Here, FIG. 4 is a plan view conceptually showing the distribution of the recording density of the optical disk according to the second embodiment, and FIG. 5 is the side of the two different recording layers to which the laser beam is irradiated. FIG. 4 is an explanatory diagram conceptually showing a mode of recording information on a recording layer on a far side as viewed from the outside.

 As shown in FIG. 4, the optical disc 100b according to the second embodiment has a plurality of regions having different recording densities in the same recording layer (for example, the L0 layer). Specifically, for example, in the LO layer, the recording density in the relatively inner recording area indicated by S1 is different from the recording density in the relatively outer recording area indicated by S2. . For this reason, the recording characteristics and the linear velocity (or the rotation speed of the optical disc) in the first recording layer 107 (or in the second recording layer 207) are sufficiently taken into consideration, and a more favorable recording density is obtained. Information can be recorded.

Further, the recording density in the L1 layer may be changed according to the state of the LO layer, for example, as shown in FIG. 5, regardless of the position in the recording layer. Specifically, as shown in FIG. 5 (a), the recording density in the recording area of the L1 layer corresponding to the recording area of the LO layer where information has been recorded, and as shown in FIG. 5 (b), The recording density in the recording area of the L1 layer corresponding to the recording area of the LO layer in which no information is recorded may be different. More specifically, when the LO layer is already recorded, the irradiated laser beam LB is liable to be scattered, etc., so that the recording density of the L1 layer is relatively low (that is, relatively coarse). Is preferably recorded. On the other hand, when the LO layer is unrecorded, information pits may be recorded so that the recording density of the L1 layer becomes relatively large (that is, relatively dense). [0049] For example, in the case of an information recording / reproducing apparatus to be described later, when recording information on the L1 layer, the state of the LO layer (that is, the force at which the information is recorded and unrecorded is determined in advance, and the It is preferable that the recording density in the L1 layer is determined according to the determination result.

 (Information recording / reproducing device)

 Next, with reference to FIG. 6, the configuration and operation of an embodiment of an information recording / reproducing apparatus for recording / reproducing data using the information recording medium according to the present invention will be described.

 First, the configuration of the information recording / reproducing device 300 according to the embodiment of the present invention will be described with reference to FIG. FIG. 6 is a block diagram of the information recording / reproducing apparatus 300 according to the embodiment of the present invention. The information recording / reproducing device 300 has a function of recording the recording data on the optical disk 100 and a function of reproducing the recording data recorded on the optical disk 100.

 The internal configuration of the information recording / reproducing device 300 will be described with reference to FIG. The information recording / reproducing device 300 is a device that records information on the optical disc 100 and reads information recorded on the optical disc 100 under the control of the processor 354.

 The information recording / reproducing device 300 includes an optical disk 100, a spindle motor 351, an optical pickup 352, a signal recording / reproducing means 353, a processor (drive control means) 354, a memory 355, a data input / output control means 306, and an operation button 310. , A display panel 311, and a bus 357.

 The spindle motor 351 rotates and stops the optical disk 100, and operates when accessing the optical disk. More specifically, the spindle motor 351 is configured to rotate and stop the optical disc 100 at a predetermined speed while receiving spindle servo from a servo unit (not shown) or the like.

 In the present embodiment, in particular, the data recording operation is performed according to the clock signal indicated by the preformat address information such as the wobbles 109 and land pre-pitched LPP formed on the optical disc 100 in advance. That is, the spindle motor 351 controls the rotation of the optical disc 100 based on the preformat.

The optical pickup 352 performs recording and reproduction on the optical disc 100, and includes a laser device and a lens. More specifically, the optical pickup 352 irradiates the optical disc 100 with a light beam such as a laser beam at a first power as reading light during reproduction, and At the time of recording, the recording light is irradiated with the second power while being modulated.

The signal recording / reproducing unit 353 performs recording / reproducing on the optical disc 100 by controlling the spindle motor 351 and the optical pickup 352.

The memory 355 is used for all data processing in the disk drive 300, such as a buffer area for recording / reproducing data and an area used as an intermediate buffer when converting into data that can be used by the signal recording / reproducing means 353. You. The memory 355 is composed of a ROM area for storing programs for operating these recorder devices, a buffer area for compression / expansion of video data, and a RAM area for storing variables necessary for the program operation. Is done.

 [0059] The CPU (drive control means) 354 is connected to the signal recording / reproducing means 353 and the memory 355 via the bus 357, and controls the entire information recording / reproducing apparatus 300 by giving an instruction to each control means. . Normally, software for operating the CPU 354 is stored in the memory 355.

 The data input / output control unit 306 controls data input / output from / to the information recording / reproducing device 300 from outside, and stores and retrieves data into / from a data buffer on the memory 355. When data input / output is a video signal, externally received data is compressed (encoded) into an MPEG format at the time of data input and output to the memory 355, and at the time of data output, the MPEG format received from the memory 355 is output. Expands (decodes) the data from and outputs it to the outside.

 The operation control means 307 receives and displays an operation instruction to the information recording / reproducing apparatus 300, and transmits an instruction by an operation button 310 such as recording or reproduction to the CPU 354, and transmits the instruction to the information recording / reproducing apparatus 300 during recording or reproduction. The operating state is output to a display panel 311 such as a fluorescent tube.

[0062] As described above, a household device, which is an example of the information recording / reproducing device 300, is a recorder device that records and reproduces video. This recorder device is a device that records a video signal from a broadcast receiving tuner or an external connection terminal onto a disc, and outputs the video signal reproduced from the disc to an external display device such as a television. The operation as a recorder device is performed by causing the CPU 354 to execute the program stored in the memory 355. In the present embodiment, in particular, the information recording / reproducing apparatus 300 controls the optical disc 100 so that the recording densities of the first recording layer and the second recording layer are different with reference to the preformat address information. Record the recording data in Specifically, the recording data is recorded on each recording layer based on the period of the pebbles 109 indicating the preformat address information and the recording clock obtained by reading the land prepit LPP. For this reason, the recording of the first recording layer 107 is performed according to the recording density of the first recording layer 107 itself, and the recording of the second recording layer 207 is performed according to the recording density of the second recording layer 207 itself. In accordance with the above, the optical pickup 352 can perform the laser light satisfactorily using laser light having appropriate power. Therefore, the recording data can be recorded in a more suitable state on each recording layer.

 In the above-described embodiment, the description has been given by taking an optical disk having two recording layers as an example. However, a similar configuration can be adopted in an optical disk having three or more recording layers. Needless to say. Then, if a similar configuration is adopted, the various benefits described above can be enjoyed.

 [0065] The present invention is not limited to the above-described embodiments, and may be modified as appropriate without departing from the spirit or spirit of the invention which can be read by the claims and the entire specification. Information recording media and information recording / reproducing devices are also included in the technical scope of the present invention.

 Industrial applicability

The information recording medium according to the present invention is applicable to, for example, a multilayer optical disc for consumer or business use that can record various types of information at a high density.

Claims

The scope of the claims  [1] It has at least a first recording layer and a second recording layer for recording information,  The first recording layer and the second recording layer each have a groove track for recording the information having the same track pitch, and have different recording densities of the information recorded on each recording layer. An information recording medium characterized by being preformatted to generate a clock for recording as described above. [2] The pre-format of the first recording layer and the second recording layer is performed by the groove track oscillating at a different cycle in each recording layer. An information recording medium according to paragraph 1. [3] Each of the first recording layer and the second recording layer is further formed with a land prepit indicating a recording address position on the groove track,  3. The information recording medium according to claim 2, wherein the land prepits in each recording layer are formed so that recording densities of the information recorded in each recording layer are different. .  [4] The pre-format is performed on each of the first recording layer and the second recording layer such that reproduction jitter of the information recorded on each recording layer is minimized. An information recording medium according to paragraph 1 of the scope.