JP2006024290A - Optical disk and information recording method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical disk which enables stable recording and reproducing by setting a rule for realizing a double-layered DVD-R. <P>SOLUTION: In a double-layered write once type optical disk 100, a relative positional deviation in the radial direction between the addresses on the respective layers L0, L1 is expressed as a difference between the addresses, and the differential information is recorded on a writable administrative information area of this optical disk. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical disc having a two-layer structure and effective as a write-once recording medium, and an information recording method therefor.

In recent years, a write-once optical disc (CD-R) has been developed, and music data, video data, and the like can be recorded on the CD-R using a recording device. Recently, a DVD (digital versatile disk) capable of recording a large amount of data has been developed as this type of medium. In addition, since a DVD has a thickness similar to that of a CD by bonding two substrates, a proposal of being configured as a two-layer disc has been issued. However, although the dual-layer disc is an international standard for DVD-video or DVD-ROM and details are widely known, the recordable type is widely used for the single-layer structure. Regarding the layer structure, details of what has recently been commercialized are not known.
Japanese Patent Laid-Open No. 11-259917

  Here, in order to realize a dual-layer DVD-R, several problems must be solved. Now, in a write-once two-layer optical disk, the recording layer close to the optical head is L0, and the far side is L1. In this case, when recording the far layer L1, recording is performed with the light that has passed through the near layer L0. To record normally, it is necessary to record with a predetermined recording beam power (light intensity), but the transmittance of the near layer L0 varies depending on whether or not the near layer L0 has been recorded. For this reason, when straddling the unrecorded area and the recording area of the near layer L0 during recording of the far layer L1, the recording beam power reaching the far layer L1 fluctuates and normal recording cannot be performed.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an optical disc and a recording / reproducing method therefor, in which a rule is set to realize a DVD-R having a two-layer structure, and stable recording / reproducing is possible.

  In the present invention, in a two-layer write-once optical disc, the shift amount of the relative position in the radial direction of the address of each layer (the far layer L1 and the near layer L0) is expressed as an address difference, and the information on the difference is expressed as follows: It is recorded in the recordable management information area of this optical disc.

  By the above means, when information is recorded on the layer (L1) far from the head by the optical head, the address to be recorded can be managed. For this reason, when recording information on the far layer (L1), for example, it is possible to record via only one of the recorded area and unrecorded area of the near layer (L0). As a result, there is no power fluctuation of the irradiation beam reaching the far layer (L1), and stable recording is possible.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 schematically shows a state in which a beam 201 is irradiated to a two-layer write-once disc 100 through an objective lens 200. L0 is a layer near the optical head (hereinafter referred to as a first layer), and L1 is a layer far from the optical head (hereinafter referred to as a second layer). In the state shown in the figure, the focal point of the beam 201 coincides with the second layer L1.

  FIG. 2 shows an enlarged view of the vicinity where the beam spot is formed. Now, it is assumed that the first layer L0 includes an unrecorded area AR1, a recorded area AR2, and an unrecorded area AR2 from the left to the right (in the track, from the inner periphery to the outer periphery). Further, the boundary between the unrecorded area AR1 and the recorded area AR2 is shown as ADR1, and the boundary between the recorded area AR2 and the unrecorded area AR3 is shown as ADR2.

  In addition, it is assumed that an unrecorded area exists in the second layer L1 corresponding to the areas AR1 to AR3.

  Here, it is assumed that data is recorded through the recorded area AR2 as the first rule of recording (beam power P1). Then, as shown in FIG. 2, the recordable area AR3 is restricted inside the recorded area AR2. That is, the boundary ADR3 of the recordable area AR3 is outside the boundary ADR1, and the boundary ADR4 is inside the boundary ADR2.

  This relationship is a relationship for obtaining stable recording in the recordable area AR4. The deviation between the boundary ADR1 and ADR3 is preferably equal to or greater than the radius of the beam spot formed in the first layer L0.

  Here, in the write-once optical disc, the recording position is determined using the first address information recorded in advance on the disc. The first address information is a unit in which an ECC (error correction code) block can be recorded, for example, by prepits, and is recorded along the track direction by land prepits. This address is a physical address and is recorded when the disc is manufactured.

  Further, the information itself recorded on the track includes the second address information. The second address information is recorded by being included in the header of the recording data. Here, the first address corresponds to the second address based on a certain rule. The second address is a recording physical address obtained by conversion based on the first address. The first address is used to detect the physical address on the disk, and the second address is used to detect the physical address of the recording data on the disk.

  The correspondence rule may depend on information indicating which layer is L0 or L1. For example, the first address may increase in the same way from the inner periphery to the outer periphery in the first and second layers. In this case, the additional information recorded together with the address includes the layer identification information. In some cases, the first address increases from the inner periphery to the outer periphery of the first layer, and continuously increases from the outer periphery of the second layer toward the inner periphery. The second address represents the data recording start position, recording end position, and the like by converting the first address.

  In the case of a write-once disc, each time data is additionally written, a second address indicating the start and end of data writing is additionally recorded in the management area as the latest information.

  As described above, in order to record information on the second layer L1, it is necessary to determine whether or not the corresponding first layer L0 has been recorded. For this purpose, it is necessary to be able to determine the position from the address information.

  For this purpose, the correspondence between the address of the second layer L1 and the address of the first layer L0 (here, the correspondence of the first address described above) must be constant. For example, for simplicity, it is assumed that the same address is set in the first layer L0 and the second layer L1.

  In this case, when recording at the address A of the second layer L1, the address A of the first layer L0 is at the same radial position, and a certain range before and after the address A of the first layer L0 (this range is (It is determined by the beam radius at the above-mentioned L0), but it is sufficient that either one is recorded or not recorded.

  However, the relationship between the first address recorded on the disc and its position (radial position) has an error between the two layers. When this amount is large, it becomes difficult to accurately grasp and determine the relationship between the address and the position using the address information.

  There are several causes for this positional relationship error. Before this explanation, one track is defined here.

  FIG. 3 is a diagram showing the track 31. A recording unit, for example, the tip of an ECC block is indicated by a black dot in the radial direction. Here, a track is provided on the spiras from the inner periphery toward the outer periphery. Starting from this address, one track is defined as the end of the minimum address that has passed one or more laps. In this way, the width of the overlapped portion is doubled, but the track pitch is about 0.7 um in DVD, so it is sufficient to discuss in units of error of about um. If the ECC block which is a recording unit can be further divided and identified, only the minimum range and the last division unit may be partially adjacent to each other. In actuality, it is sufficient to select whether to use the ECC block or the internal division unit for the convenience of measurement.

Now, one of the factors causing an error in the positional relationship between layers is eccentricity.
FIGS. 4A to 4C show one track of the first layer L0 and the second layer L1, and when there is no error, L0 and L1 are from the disk rotation axis direction. When viewed, it is assumed that they are in exactly the same position.

  The eccentric example in FIG. 4A is an example in which the centers of the layer L0 and the layer L1 are shifted in opposite directions with respect to the rotation center of the disk. The eccentricity in FIG. 4B is when the direction and amount are exactly the same, and at this time, the positions of the layers L0 and L1 are the same.

  Such eccentricity is caused by misalignment when a hole for a rotating shaft is made in the disk substrate, misalignment caused when the layers L1 and L0 are bonded, and the like.

  The next factor is the radius error. FIG. 4C shows a case where the same value and radius are shifted over the entire circumference. This radius error is determined when the disk is manufactured. In general, when the same master recording machine is used, this deviation does not change greatly even if the radius changes. That is, even if the recording start position is deviated, the linear recording density and the track pitch error between the layers L0 and L1 are small.

  Therefore, after manufacturing the disc, the positional relationship error is measured, and the relative position error amount is recorded in a part of the disc management information recording area provided on the disc. This value is used to reduce position errors when performing address recognition.

  For example, it is assumed that the first address of the layer L0 is A0, and the first address of the layer L1 having the same radius is set to A1. Since the radius is shifted, the values A0 and A1 are actually different. Then, as D = A1-A0, D is recorded in the management information recording area of the disc.

  An information recording / reproducing apparatus for recording / reproducing information with respect to the two-layer disc can use this information D to accurately determine the first addresses at the same radial positions of the layers L0 and L1. When recording at the first address B of the layer L1, the first address of the corresponding layer L0 is BD. That is, if an area obtained by adding the above-described beam radius to the GAP (described later) with BD as the center and recording the inner and outer weeks has been recorded, it can be determined that information recording can be performed with the set power. .

  Actually, the ideal value of D may be slightly different depending on the radial position. In this case, it is only necessary to set D so that the radial error is minimized on the entire surface. For example, what is necessary is just to obtain | require D of several places in a radial direction, and employ | adopt the average.

  As described above, by managing the radial error D between the first layer L0 and the second layer L1, when recording at the first address B of the second layer L1, the corresponding first The first address of the layer L0 is BD.

  Even if the first address is adjusted so that the radius error is minimized as described above, the influence of eccentricity still remains. Therefore, in the present invention, in order to further improve accuracy, the maximum deviation of one track after the first address adjustment of the layers L0 and L1 is treated as a gap (GAP) as shown in FIG. The specification of the disk is determined so as to be the quantity. In other words, it is assumed that a disk whose GAP is equal to or smaller than a certain amount is a disk of specifications (standard). By setting in this way, it becomes possible to design the recording ability and the reproducing ability in accordance with the disc standard in the recording device and the reproducing device on the user side.

  Here, as shown in FIG. 6, the recording area (or width) of the layer L1 is in the radial direction from the layer L0 by the value obtained by adding the aforementioned beam radius to the above GAP (the amount shown in FIG. 2). What is necessary is just to make each both ends narrow.

  FIG. 6 shows a case where recording is possible in the layer L1 when passing through the recorded area of the layer L0. Of course, recording is possible even when passing through the unrecorded area of the layer L0. It is.

As described above, the recordable area of the layer L1 is an area obtained by reducing both ends in the radial direction by (GAP + beam radius) from the recorded area of the layer L0. However, in order to actually record data in the layer L1, it is necessary to convert the value of (GAP + beam radius) into an address difference between layers of the first address. When recording on an optical disk with a constant linear recording density, the first address difference corresponding to the radial width varies depending on the radius.

  Therefore, first, the radius R1 is obtained from the first address A1 at the end of the region of the layer L0, and then the radius R2 obtained by adding or subtracting (GAP + beam radius) to the radius R1 is obtained. An address A2 (on the layer L0) corresponding to the radius R2 is obtained. Thereafter, the layer L1 address corresponding to the address A2 may be obtained.

  For example, it calculates | requires as follows. First, a radius serving as a reference of the disk is R0 and an address is A0. This is, for example, the address and radius of the start portion of the data area where user data can be recorded.

  Assume that one of the addresses at the end of the L0 area is A1. The radius R1 is obtained by the following formula.

(R1 ² −R0 ² ) = K (A1−A0) (1)
Here, K is a value determined from the track pitch, linear recording density, 1 address size, and address direction, and is obtained by dividing the area of 1 recording unit by 2π. R1 is obtained from this equation. R1 is a positive value. Let G be the value obtained by adding the beam radius to the maximum GAP defined in the standard.

When R1 is the outer edge in the radial direction of the region, the maximum recordable radius R2 of L1 is R2 = R1-G (2A)
It becomes.

On the contrary, when R1 is the end in the radial direction of the area, the minimum recordable radius R2 of L1 is R2 = R1 + G (2B)
It becomes. Next, an address A2 corresponding to R2 is obtained.

The formula changes slightly depending on whether R1 is larger or smaller than R2. When R2 is smaller than R1 (when R2 is obtained by Equation 2A)
(R1 ² −R2 ² ) ≦ K (A1−A2) (3A)
The maximum address A2 that satisfies is the address to be obtained. Here, it is assumed that the address is an integer and changes in increments of one.

When R2 is larger than R1, (when R2 is obtained by Equation 2B):
(R2 ² −R1 ² ) ≦ K (A2−A1) (3B)
The minimum address A2 that satisfies is the address to be obtained.

  In this way, the address A2 corresponding to the region of the layer L1 on the layer L0 is obtained. Next, the address is converted into the address of the layer L1 based on a predetermined address conversion rule between the layer L0 and the layer L1. For example, if the addresses between the layer L0 and the layer L1 are determined to coincide with each other, the address A2 becomes the address of the layer L1. If addresses are assigned continuously from the layer L0 to the layer L1, A2 + (the maximum address of the layer L0) is obtained.

  Now, the values of R0 and K based on the above calculation have an error with respect to the values determined by the standard. Therefore, by recording the value of R0 and the value of K on the disk and using the above calculation, the position can be determined with higher accuracy, and the recording quality is improved.

  Note that one of the values of R0 and K may be recorded on the disc, and the value not recorded may be a value obtained from the disc standard.

  Alternatively, the values of R0 and K may not be recorded directly, but an error from the standard value determined by the standard may be recorded. Also, the value of K is obtained by dividing the area of one recording unit by 2π. However, it is possible to modify the area of one recording unit by adding a constant 2π to the equation. In short, by recording error management information of the first address (physical address) between the layers in the management area of the two-layer type optical disc, it is appropriate to record information on the second layer. The area can be selected, and high quality recording is possible. In the disc of the present invention, an address indicating a recording position for each recording unit is recorded on a spiral track, and at least a radius or a diameter of a position of a specific address and a value representing a recording area per address are recorded. Either one of the information is recorded in a recordable management information area of the disc. Therefore, it is possible to determine an appropriate recording address based on the error management information.

  As described above, according to the present invention, in the two-layer write-once optical disc, the area that can be recorded on the layer L1 can be obtained with high accuracy.

  The first address can be corrected, the reference radius R0 is recorded, and a value corresponding to the area of one recording unit is recorded on the disk, so that the required accuracy at the time of manufacturing the disk stamper is reduced and the recordable area is accurately obtained. If the recordable area is accurately obtained by determining the allowable GAP, it is guaranteed that L0 is recorded in L1 through the recorded area or L0 is recorded through the unrecorded area. . Therefore, the quality of the recording signal is improved, the error rate is reduced, and reliable recording can be performed.

  FIG. 7 shows a configuration diagram of a mastering apparatus which is a part of an optical disk medium manufacturing apparatus according to an embodiment of the present invention.

  The master 111 is cut by the laser beam from the optical system 112. The master 111 is driven to rotate by the spindle of the spindle and slider unit 113. The optical system 112 is controlled to move by a slider. Reflected light reflected from the optical disk, which is the master disk, via the optical system 112 is converted into an electrical signal by the photodetector 114, and its output is input to the servo circuit 115. The servo circuit 115 controls tracking, focusing, and the like of the optical system 112 using a control signal generated based on a control signal from the controller 116 and an electric signal from the photodetector 114. The servo circuit 115 controls the rotation speed of the master disk via the spindle and slider unit 113.

  The controller 116 controls the formatter 117. The formatter 117 controls the laser light emitted from the optical system 112 to the master 111 by controlling the laser driver 118. The formatter 117 controls the optical system 112 so that addresses are formed.

  That is, in the mastering apparatus of FIG. 7, the laser light quantity of the optical system 112 is controlled based on the signal output from the formatter 117 to the laser driver (LDD) 118. Laser light passes through an AO modulator, an objective lens, and the like included in the optical system 112 and is irradiated onto the master. The focus of irradiation light and the like are controlled by the servo circuit 115. Further, the rotation of the disk and the position in the radial direction are similarly controlled. Since the portion of the master that is exposed to light is exposed, this portion becomes a guide groove or the like.

  FIG. 8 shows a flowchart for creating an optical disk medium. The optical disk medium of the present invention is manufactured by the steps of master production (step ST1), stamper creation (step ST2), molding (step ST3), medium film formation (step ST4), and bonding (step ST5). In the master production process, a resist is applied to a flat master, the resist on the master is exposed by the mastering device in FIG. 7, and the exposed resist is removed by development, so that the information recording layer of the final optical disk medium Create a master with similar irregularities. In the stamper creation process, the master is plated with Ni or the like to form a sufficiently thick metal plate, and the master is peeled off to produce a stamper. At this time, the unevenness formed on the master is reversed and formed on the stamper. Next, in the molding process, a stamper is used as a model, and a resin such as polycarbonate is poured into the stamper to mold the substrate. At this time, the unevenness of the surface of the molded substrate is a transfer of the unevenness of the stamper, that is, substantially the same as the unevenness of the master. Next, another substrate is laminated to complete a two-layer optical disk medium.

  FIG. 9 is a configuration example of a recording / reproducing apparatus. This recording / reproducing apparatus has two types of disk drive units. The optical disc 501 is an information recording medium that can construct a video file. The disk drive unit 502 rotationally drives the optical disk 501 to read / write information. A hard disk drive unit 504 drives the hard disk. The data processor unit 503 can supply recording data to the disk drive unit 502 and the hard disk drive unit 504, and can receive a reproduced signal. The disk drive unit 502 includes a rotation control system, a laser drive system, an optical system, and the like for the optical disk 501.

  The data processor unit 503 handles recording or reproduction unit data, and includes a buffer circuit, a modulation / demodulation circuit, an error correction unit, and the like.

  This recording / reproducing apparatus mainly includes an encoder unit 600 that constitutes a recording side, a decoder unit 700 that constitutes a reproducing side, and a microcomputer block 800 that controls the operation of the apparatus body. The encoder unit 600 includes an analog-to-digital converter for video and audio that digitizes an input analog video signal or analog audio signal, a video encoder, and an audio encoder. Furthermore, a sub-picture encoder is also included.

  The output of the encoder unit 600 is converted into a predetermined DVD-R format by the formatter 604 including the buffer memory 603 and supplied to the data processor unit 503. The encoder unit 600 receives an external analog video signal and an external analog audio signal from the AV input unit 611 or an analog video signal and an analog audio signal from the TV tuner 612. Note that when the directly compressed digital video signal or digital audio signal is directly input, the encoder unit 600 can also supply the compressed digital video signal or digital audio signal directly to the formatter 604. The encoder unit 600 can also directly supply a digital video signal or audio signal subjected to analog-digital conversion to the video mixing unit 705 or the audio selector 701.

  In the video encoder included in the encoder unit 600, the digital video signal is converted into a digital video signal compressed at a variable bit rate based on the MPEG2 or MPEG1 standard. The digital audio signal is converted into a digital audio signal compressed at a fixed bit rate based on the MPEG or AC-3 standard or a linear PCM digital audio signal.

  When a sub-video signal is input from the AV input unit 611 (for example, a signal from a DVD video player with an independent output terminal of the sub-video signal), or a DVD video signal having such a data structure is broadcast and is used as a TV tuner. When received at 612, the sub-video signal in the DVD video signal is encoded (run-length encoded) by the sub-video encoder to become a sub-picture bitmap.

  The encoded digital video signal, digital audio signal, and sub-picture data are packed by the formatter 604 to form a video pack, an audio pack, and a sub-picture pack, and these are assembled to form a DVD-recording standard (for example, DVD-RAM). , DVD-R, DVD-RW, etc.).

  Here, this apparatus uses the data processor unit 503 to send information (packets of video, audio, sub-picture data, etc.) formatted by the formatter 604 and the created management information to the hard disk drive unit 504 or the data disk drive unit. 502 can be recorded on the hard disk or the optical disc 501. Information recorded on the hard disk or the optical disk can also be recorded on the optical disk 501 or the hard disk via the data processor unit 503 and the disk drive unit 502.

  It is also possible to perform an editing process such as deleting a part of video objects of a plurality of programs recorded on the hard disk or the optical disc 501 or connecting objects of different programs. This is because data units handled by the DVD format are defined to facilitate editing.

  The microcomputer block 800 includes an MPU (micro processing unit) or CPU (central processing unit), a ROM in which a control program and the like are written, and a RAM for providing a work area necessary for executing the program. Yes.

  The MPU of the microcomputer block 800 executes defect location detection, unrecorded area detection, recording information recording position setting, UDF recording, AV address setting, etc. using the RAM as a work area according to the control program stored in the ROM. To do.

  The microcomputer block 800 includes an information processing unit necessary for controlling the entire system, and includes a work RAM, a directory detection unit, a VMG (total video management information) information creation unit, a copy-related information detection unit, and a copy. And a scrambling information processing unit (RDI processing unit), a packet header processing unit, a sequence header processing unit, an aspect ratio information processing unit, and the like.

  Among the execution results of the MPU, contents to be notified to the user are displayed on the display unit 802 of the video data recording / reproducing apparatus, or are displayed on the monitor display by OSD (on-screen display). The microcomputer block 800 has a key input unit 801 that gives an operation signal for operating the apparatus. The timing at which the microcomputer block 800 controls the disk drive unit 502, the hard disk drive unit 504, the data processor unit 503, the encoder unit 600, and / or the decoder unit 700 is based on time data from an STC (system time clock) 803. Can be executed. Recording and playback operations are normally executed in synchronization with the time clock from the STC 803, but other processes may be executed at a timing independent of the STC 803.

  The decoder unit 700 separates and extracts each pack from a DVD format signal having a pack structure, a memory used when pack separation or other signal processing is performed, and main video data (video pack) separated by the separator. A V decoder that decodes the content), an SP decoder that decodes the sub-picture data separated by the separator (the contents of the sub-picture pack), and an A decoder that decodes the audio data separated by the separator (the contents of the audio pack) Have A video processor is also provided that appropriately synthesizes the decoded sub-video with the decoded main video and outputs the main video with a menu, a highlight button, subtitles, and other sub-videos.

  The output video signal of the decoder unit 700 is input to the video mixing unit 705. In the video mixing unit 705, text data is synthesized. The video mixing unit 705 is also connected to a line that directly takes in signals from the TV tuner 612 and the A / V input unit 611. A frame memory 706 used as a buffer is connected to the video mixing unit 705. When the output of the video mixing unit 705 is an analog output, it is externally output via an I / F (interface) 707, and when it is a digital output, it is output externally via a digital / analog converter 708.

  The output audio signal of the decoder unit 700 is analog-converted by the digital-analog converter 702 via the selector 701 and output to the outside. The selector 701 is controlled by a select signal from the microcomputer block 800. Accordingly, the selector 701 can directly select a signal that has passed through the encoder unit 600 when directly monitoring a digital signal from the TV tuner 612 or the A / V input unit 611.

  Note that the formatter of the encoder unit 600 creates segmentation information during recording and periodically sends it to the MPU of the microcomputer block 800 (information at the time of GOP head interrupt, etc.). The segmentation information includes the number of packs of VOBU (video object unit), the end address of the I picture from the beginning of the VOBU, the playback time of the VOBU, and the like.

  At the same time, information from the aspect information processing unit is sent to the MPU at the start of recording, and the MPU creates VOB stream information (STI). Here, the STI stores resolution data, aspect data, and the like, and at the time of reproduction, each decoder unit is initialized based on this information.

  In this apparatus, one video file is recorded on one disc. In order to continue playback without interruption while accessing (seeking) data, a minimum continuous information unit (size) is determined. This unit is called CDA (Contiguous Data Area). The CDA size is a multiple of an ECC (error correction code) block (16 sectors), and the file system records in this CDA unit.

  The data processor unit 503 receives data in VOBU units from the formatter of the encoder unit 600 and supplies data in CDA units to the disk drive unit 502 or the hard disk drive unit 504. Further, the MPU of the microcomputer block 800 creates management information necessary for reproducing the recorded data. When the MPU recognizes a data recording end command, it sends the created management information to the data processor unit 503. Thereby, the management information is recorded on the disc. Therefore, when encoding is performed, the MPU of the microcomputer block 800 receives information (eg, segmentation information) from the encoder unit 600. In addition, the MPU of the microcomputer block 800 recognizes management information (file system) read from the optical disk and the hard disk at the start of recording, recognizes an unrecorded area of each disk, and sets a data processor area 503 as a recording area on data. Is set to disk via.

  The microcomputer block 800 has a function of specifying, for example, a recorded area (or an unrecorded area) of the recording layer L0 when information is recorded on the recording layer L1 described above. In addition, a function for obtaining an address for the first recording layer L1 from error information recorded in the management area of the disc is provided. These are collectively shown as an address processing unit in the L1 layer recording.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine suitably the component covering different embodiment.

Explanatory drawing which shows the relationship between the optical disk of the 2 layer structure which concerns on this invention, and a light beam. Explanatory drawing which shows the example of the recordable area | region of the optical disk which concerns on this invention. Explanatory drawing of the track | truck in the optical disk based on this invention. An explanatory view showing an example of an eccentric state of a track between layers in an optical disc having a two-layer structure. FIG. 4 is an explanatory diagram shown to explain the relationship between the maximum gap caused by the track misalignment between the layers and the disk specifications. FIG. 4 is an explanatory diagram shown to explain the relationship between the maximum gap caused by the track misalignment between the layers and the disk specifications. The figure which shows the structural example of the mastering apparatus which is a part of optical disk manufacturing apparatus. The figure which shows the example of the flowchart of optical disk medium preparation. The figure which shows the structural example of the recording / reproducing apparatus which records and reproduces information on the optical disk which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Optical disk, 200 ... Objective lens, L0 ... 1st layer, L1 ... 2nd layer.

Claims (6)

  In a two-layer write-once optical disc, the shift amount of the relative position in the radial direction of the address of each layer is expressed as an address difference, and the information on the difference is recorded in the recordable management information area of the optical disc. An optical disc characterized by   In a two-layer write-once optical disc, an address indicating a recording position for each recording unit is recorded on each layer in a spiral track, and is composed of recording units from an address AS to an address AE, and the area of the address AS An area having at least one turn from the leading edge of the address AE to the trailing edge of the area of the address AE can be defined, and the maximum amount of radial deviation between the areas A0 and A1 of each layer assumed to be the same radius in an ideal state is defined. An optical disc characterized by the above.   An address indicating a recording position for each recording unit is recorded on a spiral track, and information on at least one of a radius or a diameter of a position of a specific address and a value indicating a recording area per address is recorded on the disc. An optical disc recorded in a recordable management information area. Error management information of physical addresses between layers of a two-layer type optical disc is recorded in the management information recording area of the optical disc, and the information is recorded on the optical disc.
Of the two layers, a layer closer to the objective lens for condensing the light beam is a first layer L0, a layer farther from the objective lens is a second layer L1, and when recording information on the second layer L1, Using the error management information to recognize the address of the first layer L0 relative to the address of the second layer;
Whether information is to be recorded for the corresponding address of the second layer L1 is determined according to whether information has been recorded for the address of the first layer L0. Information recording method.   5. The information recording method according to claim 4, wherein when information is recorded at the address of the second layer, it is premised that information has already been recorded at the address of the corresponding first layer L0. .   When the gap between tracks between the first layer L0 and the second layer L1 is GAP, and the radius of the beam spot in the first layer when the light beam is focused on the second layer is r1, the error 5. The information recording method according to claim 4, wherein the management information is information indicating at least (GAP + r1) or more.

Images