JP2004158173A - Method and apparatus for recording optical information - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly reliable recording method and apparatus for optical disks, which can detect more stable reproduction signals from other recording layers without influenced by the difference of transparency caused by recorded/not recorded parts on a recording layer when reproducing an optical disk provided with a plurality of information recording layers. <P>SOLUTION: An optical disk is provided with a first recording layer 102 and a second recording layer 104 that is placed at the side farther than the first recording layer 104 from a light source. If data are recorded on the second recording layer 104, a data recordable area 403 of the second recording layer 104 is set within the radius of the second recording layer 104 corresponding to the outermost circumference of an area recorded with data on the first recording layer 102 and then data is recorded. <P>COPYRIGHT: (C)2004,JPO

Description

  The present invention relates to a recording method and a recording apparatus for a multi-layer optical disc having a plurality of recording layers and capable of optically recording and reproducing information with respect to each recording layer.

  In recent years, various types of optical disks capable of recording and reproducing a large amount of information have been researched and developed. As one of large-capacity optical disks, there is a double-sided optical disk capable of bonding two optical disks and recording / reproducing on both sides. However, in fields requiring random access frequently, such as recording media for video recording, it is desired that the recording capacity of the optical disc is large and at the same time, it is possible to access arbitrary data without turning over. There's a problem.

  Therefore, as an optical disk that records a large amount of data on one optical disk and is randomly accessible, a multilayer optical disk having two or more recording layers and capable of recording and reproducing information from one side has been proposed. became.

  Recording on the recording layer of an optical disc is usually performed by irradiating a laser beam on the surface of the recording medium to form pits having changed optical characteristics since the recording layer usually uses a phase change material, an organic dye film or the like. However, considering that information is actually recorded / reproduced on / from an optical disc having a plurality of recording layers, when recording is performed on a recording layer on the back side when viewed from the irradiation surface of the laser beam, recording / unrecording on the recording layer on the front side is not performed. Due to the difference in optical characteristics due to recording, the power of the laser beam reaching the recording layer on the back side varies, which may adversely affect the recording / reproducing operation. The following countermeasures have been considered for this.

  As one method, even if there is an area that is determined to be unrecordable during data recording, dummy data is recorded and unified to the recorded area to reach the other layer without differences in optical characteristics In this method, the power of the laser beam to be emitted is made uniform (for example, see Patent Document 1).

WO 01/18799 pamphlet (see FIG. 24 and the like)

  Such a rewritable optical disk generally has a sector structure, and the recording operation is performed in sector units. Therefore, when performing recording / reproduction on an optical disk having a plurality of recording layers, the following problems are posed. was there.

  In general, a sector includes an address area 116, a user data area 120, gap areas 117 and 119, and a buffer area 121 as shown in FIG. Here, for simplicity of description, the test light emitting region 118 is set at the center of the gap regions 117 and 119, and the gap region is divided into two and handled.

  The address area 116 is an area having address information which is an identification signal of each sector. The user data area 120 is an area for recording user data having a synchronization signal at the beginning or end in a sector. The test light emitting area 118 is provided between the address area 116 and the user data area 120, and is used for adjusting the optical output of the semiconductor laser, measuring the optical output optimal for recording, and the like. The first gap region 117 is provided between the address region 116 and the test light emitting region 118, and is a space for preventing signal erasure in the address region 116 when the light output is adjusted in the test light emitting region 118 or the like. Area. The second gap area 119 is provided between the test light emission area 118 and the user data area 120 and plays a role similar to that of the first gap area 117, but is used when recording user data in the user data area 120. It is possible to record the same signal as the synchronization signal at the head of the data in the second gap area 119. The buffer area 121 is an area for absorbing the rotational accuracy of the motor of the optical disk drive.

  In general, since the recording operation is not performed on all of the first gap region 117, the test light emitting region 118, the second gap region 119, and the buffer region 121, the recording state is not accurately continued and the laser is not accurately performed. If the optical characteristics of the recording layer closer to the light source become non-uniform, the power of the laser light reaching the recording layer farther from the laser light source becomes non-uniform. Therefore, there is a case where the problem of the optical characteristics may occur only by performing the dummy recording only in the user data area 120 as in the conventional example.

  Hereinafter, this problem will be specifically described using a two-layer disc as an example. FIG. 9A is a diagram illustrating the structure of an optical disc having a first recording layer 102 and a second recording layer 104. In the following description, in the first recording layer 102, the user data area is in a recording state, the first gap area, the second gap area, and the buffer area are in an unrecorded state, and the central part of the test light emitting area The power of the laser beam that reaches the second recording layer when is in the recording state will be described. In the first recording layer 102, an area 501 is a recorded area, and an area 502 is an unrecorded area. The address area 116, the first gap area 117, the test light emission area 118, the second gap area 119, the user data area 120, and the buffer area 121 constitute a sector.

  The first recording layer 102 and the second recording layer 104 are made of a phase change material. Further, the first recording layer 102 has optical characteristics as shown in FIG. The recording layer is in a crystalline state when data is not recorded, and data is recorded by irradiating laser light to form pits in an amorphous state.

  When the laser light 402 having the same power is applied to each area in the sector, the power of the laser light reaching each area of the second recording layer 104 differs depending on the recording state of the first recording layer 102. This is because the first recording layer 102 has an optical characteristic that the transmittance is different between when it is crystalline and when it is amorphous. In this optical characteristic, the transmittance is higher in the amorphous state than in the crystalline state. Therefore, as the ratio of the recording portion of the first recording layer 102 in the beam spot area of the laser beam 402 increases, the laser beam 402 This means that the number reaches the second recording layer more.

  FIGS. 9C to 9E show a test light emission area where data is not recorded, a user data area 120 where data is entirely recorded, and data recorded in a part of the first recording layer 102. FIG. 9 is a diagram showing the power of the laser light reaching the second recording layer 104 when a laser beam is applied to each of the boundaries between the user data area and the buffer area. When the user data area 120 is irradiated with the laser beam 402, the power of the laser beam reaching the second recording layer becomes the largest. Therefore, there is a problem that a difference occurs in the power of the reflected light from the second recording layer depending on whether the area in the sector in the first recording layer is recorded / unrecorded, and the reproduced signal is distorted. May occur.

  The present invention solves the problems described above, and when reproducing an optical disc having a plurality of information recording layers, is not affected by a difference in transmittance due to a recorded / unrecorded portion of one recording layer, and is not affected by other recording layers. An object of the present invention is to provide a highly reliable optical disk recording method and recording device capable of detecting a stable reproduction signal.

  A first recording method according to the present invention is a method for recording optical information for recording data on an optical disk having a plurality of recording layers capable of optically recording information. The optical disc has a first recording layer and a second recording layer disposed farther from the light source than the first recording layer. In the recording method, when data is recorded on the second recording layer, the radius of the outermost periphery of the data recordable range of the second recording layer is set to the outermost radius of the region where data is recorded on the first recording layer. Make the radius or less.

  A second recording method according to the present invention is a method for recording optical information for recording data on an optical disk having a plurality of recording layers capable of optically recording information. The optical disc has a first recording layer and a second recording layer disposed farther from the light source than the first recording layer. The optical disc has a track divided into a plurality of sectors, and each sector includes a buffer area at the end. In the second recording method, predetermined dummy data is recorded in a buffer area.

  A first recording apparatus according to the present invention is an optical information recording apparatus for recording data on an optical disc having a plurality of recording layers capable of optically recording information. The optical disc has a first recording layer and a second recording layer disposed farther from the light source than the first recording layer. The first recording device includes an optical head that irradiates a laser beam for recording information on an optical disk, a drive control unit that drives the optical head, and a control unit that controls the drive unit. When data is recorded on the second recording layer, the control means sets the outermost radius of the data recordable range of the second recording layer to the outermost radius of the area where data is recorded on the first recording layer. It is controlled to be less than the radius.

  A second recording device according to the present invention is a method for recording optical information for recording data on an optical disk having a plurality of recording layers on which information can be optically recorded. The optical disc includes a first recording layer, a second recording layer disposed farther from the light source than the first recording layer, and further has a track divided into a plurality of sectors. The sector includes a buffer area at the end. The second recording device includes an optical head that irradiates a laser beam for recording information on an optical disk, a drive control unit that drives the optical head, and a control unit that controls the drive control unit. The control means controls to record predetermined dummy data in the buffer area.

  According to the present invention, fluctuation of transmittance is eliminated by recording pseudo data in an area within a sector, and further, the recordable range of another layer is limited according to the recording range of the recording layer on the laser beam irradiation side. Thereby, the power of the laser beam reaching the other layer can be made uniform, and recording / reproduction can be performed under more stable conditions.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

1. Diagram 1 of the optical disc apparatus is a block diagram showing a configuration of an optical disk apparatus according to the present invention. The optical disk device includes an optical disk drive 300 and a host PC 310 that controls the optical disk drive 300.

  The optical disk drive 300 includes a spindle motor 302, an optical head 303, a laser drive circuit 304, a servo control circuit 305, a digitizing circuit 306, a digital signal processing circuit 307, a recording compensation circuit 308, and a CPU 309.

  The spindle motor 302 rotates the optical disc 301. The optical head 303 irradiates a laser beam for recording data on the optical disk 301 or reproducing data from the optical disk 301, and outputs a reproduction signal obtained by electrically converting reflected light from the optical disk 301. The laser drive circuit 304 controls the power of the laser light emitted from the optical head 303. The servo control circuit 305 performs rotation control of the spindle motor 302, position control of the optical head 303, focus and tracking control.

  The digitizing circuit 306 performs amplification, filtering, and digitization of the reproduction signal obtained from the optical head 303 to generate a digital signal (for example, a binary signal). The digitizing circuit 306 includes a PLL (not shown) therein, thereby generating a clock signal synchronized with the binarized signal.

  The digital signal processing circuit 307 performs a predetermined demodulation process on the digital signal during reproduction, performs an address extraction, an error correction process, and the like, and performs a process of adding an error correction code to recording data and a predetermined modulation process during recording. To generate modulation data. At this time, dummy data is added to the recording data as needed.

  The recording compensation circuit 308 converts the modulated data into optical modulated data composed of a pulse train, finely adjusts the pulse width and amplitude of the optical modulated data, and converts the modulated data into a recording pulse signal suitable for pit formation. The CPU 309 controls the entire optical disk drive. The host PC 310 includes a computer (not shown) and an operating system (not shown), and issues a recording / reproduction request to the optical disk drive 300.

2. Construction 2 of the optical disk, the optical disk apparatus of the present embodiment is a recording of data is a diagram showing a structure of an optical disc 301 to be reproduced. The optical disc 301 physically includes a first substrate 101, a first recording layer 102, a second recording layer 104, and a second substrate 105. Further, a clamp hole 106 is provided at the center of the optical disc 301.

  The first substrate 101 and the second substrate 105 are made of a polycarbonate resin or the like, and protect the first recording layer 102 and the second recording layer 104. The first recording layer 102 and the second recording layer 104 are bonded with an adhesive resin 103, and the adhesive resin 103 is made of a UV resin or the like. The clamp hole 106 is provided for transmitting the rotation of the spindle motor by a shaft rod and rotating the disk.

  The first recording layer 102 logically has a lead-in area 107, a defect list area 108, a spare area 109, and a data area 110. Similarly, the second recording layer 104 has a lead-in area 111, a defect list area 112, a spare area 113, and a data area 114.

  The first recording layer 102 and the second recording layer 104 have a plurality of tracks (not shown) in a spiral or concentric manner. The track is composed of a plurality of sectors 115. The sector 115 includes an address area 116, a first gap area 117, a test light emission area 118, a second gap area 119, a user data area 120, and a buffer area 121. The address area 116 has address information. The first gap area 117, the test light emission area 118, and the second gap area 119 do not normally record signals. The user data area 120 records user data having a synchronization signal at the beginning or end. The buffer area 121 absorbs the rotation accuracy of the motor.

  In the first recording layer 102 and the second recording layer 104, information recorded by a predetermined modulation rule, for example, the 1-7 modulation method, is recorded as pits on each sector 115. The pits are formed by changing the material of the recording layer into optical characteristics by the power of the laser beam. Recording and reproduction of information on the optical disk 301 are performed by irradiating a laser beam from the first substrate 101 side. Therefore, recording / reproducing of the second recording layer 104 is performed by the laser light transmitted through the first recording layer. In the present embodiment, the material of the recording layer is a phase change material, but may be an organic dye film. In this embodiment, it is assumed that the recording is performed sequentially from the inner circumference to the outer circumference of the first recording layer, and then the recording is performed from the outer circumference to the inner circumference of the second recording layer. Recording may start from the layer. The recording direction is not limited to this.

  In the present embodiment, it is assumed that address information is formed of uneven pits in each sector. The address information may be formed by a method other than the uneven pits. For example, as shown in FIGS. 3A and 3B, the track forming structure itself may include address information (for example, a digital signal). In this example, address information (digital signal) is included in a wobble shape in which a track is meandering. FIGS. 3A and 3B are diagrams showing wobble shapes 701 and 702 constituting the address information signals "0" and "1", respectively. The signals “0” and “1” are determined based on the difference in the wobble shape. FIG. 3C shows address information configured by combining wobble shapes 701 and 702 indicating signals “0” and “1”. As described above, the address information need not be formed in each sector, and may be formed by a method other than the uneven pits.

3. Recording Operation of Optical Disk Device The recording operation of the optical disk device will be described. Note that the following control can be realized by the CPU 309 executing a predetermined program and appropriately controlling the laser drive circuit 304, the servo control circuit 305, and the like.

  When recording data on the first recording layer 102 (the recording layer closer to the laser light source) of the optical disk 301, the optical disk device records dummy data in addition to the original data. This makes the recording state (crystal state) of the entire first recording layer 102 substantially uniform, transmits through the first recording layer 102, and reaches the second recording layer 104 (the recording layer farther from the laser light source). The intensity (transmittance) of the generated light can be made uniform, and the influence of the recording state of the first recording layer 102 on the reproduction signal from the second recording layer 104 can be eliminated. Hereinafter, the dummy data recording will be described in detail with reference to FIGS.

(Dummy data recording)
FIG. 4A is a diagram illustrating a state of the first recording layer 102 on which data is appropriately recorded by a method without performing dummy data recording. FIG. 4B is a diagram showing a waveform of a reproduced signal obtained when reproducing the second recording layer corresponding to the first recording layer 102 shown in FIG. That is, FIG. 4B shows a reproduction signal obtained by reflecting light transmitted through the first recording layer 102 shown in FIG. 4A at a corresponding area on the second recording layer. . As shown in FIG. 4B, a reproduction signal from the area of the second recording layer 104 corresponding to the area of the first recording layer 102 on which data is recorded, and the first recording on which no data is recorded. It can be seen that the signal level is different from the reproduction signal from the area of the second recording layer 104 corresponding to the area of the layer 102.

  Therefore, as shown in FIG. 5A, the optical disc device according to the present embodiment has an area where no data is recorded in the first recording layer shown in FIG. In addition, dummy data 203 is recorded in the buffer area 121 in addition to the original data 202. FIG. 5B shows a waveform of a reproduced signal obtained when reproducing the second recording layer corresponding to the first recording layer 102 shown in FIG. FIG. 5B shows that the signal level of the reproduction signal from the second recording layer 104 is flattened by the dummy data recording. Note that the reproduced signal waveform from the second recording layer 104 in FIG. 4B and FIG. 5B has an unrecorded state on the entire surface of the second recording layer, and the signal distortion due to the second recording layer is Do not think.

  Here, the mark 203a located at the end of the dummy data in the test light emitting area 118 or the second gap area 119 and the mark 202a located at the beginning of the recording data in the user data area 120 have a predetermined distance between marks. Record at a distance of d. Further, the mark 202b located at the end of the recording data in the user data area 120 and the mark 203b located at the beginning of the dummy data in the buffer area 121 are recorded with a predetermined distance d between the marks.

  The distance d between marks will be described. As an example, considering data having a recording mark length from 3T to 11T, the distance between each mark is also from 3T to 11T. Therefore, the distance d between marks is preferably equal to or less than 11T. However, in actuality, a slight displacement occurs due to the inclination of the disk or the like. Therefore, in consideration of the case where the distance d between marks is 11 T or more, if the distance d between marks is within 22T, which is twice as large as 11T, There is no optical effect due to the unrecorded area in the sector. That is, the distance d between marks is within twice the distance at which the recording mark length in the predetermined modulation rule is maximum. The distance d between marks is set to a length equal to or longer than the minimum mark length in a predetermined modulation rule.

  Also, an unrecorded space having substantially the same size as the first gap area 117 is secured between the buffer area 121 and the address area 116 at the head of the next sector in order to prevent signal erasure of the address area 116. .

  As shown in FIG. 4B, when no dummy data is recorded on the first recording layer 102, a laser beam reaching the second recording layer 104 due to a difference in optical characteristics between a recorded portion and an unrecorded portion. Are different, and the reproduced signal waveform is disturbed. On the other hand, as shown in FIG. 5B, when dummy data is recorded on the first recording layer 102, the optical characteristics are uniform except for the vicinity of the address area 116 where dummy data cannot be recorded. Thus, the power intensity of the laser light reaching the second recording layer 104 can be made uniform.

  The recording of the dummy data is performed when the user records the data. However, it may be performed at the time of the initial inspection performed at the time of formatting the optical disk. The purpose can be achieved by executing the recording of the dummy data only once, but the recording of the dummy data may be performed twice or more.

  In addition, the laser power for recording the dummy data is recorded with a lower power than when recording the data so that adjacent data is not erased or the transmittance of the address area is not changed. Is preferred.

  The recording range of the dummy data is equal to the entire area of the test light emitting area 118, the entire area of the second gap area 119, and the unrecorded space corresponding to the first gap area just before the address area of the next sector in the buffer area 121. Is the remaining buffer area. However, although the accuracy of address detection is slightly reduced by recording at a low power in the first gap area 117, if there is no problem in signal reproduction, the entire area of the first gap area 117 and the buffer area 121 can be used. May be recorded. In the wobble-shaped addressing method described with reference to FIGS. 3A to 3C, the address information is not erased by recording the dummy data, so that the recording range of the dummy data is outside the user data area. It is effective. As the dummy data, a synchronization signal or an arbitrary random signal recorded at the head of the user data can be considered.

(Setting of recordable range on second recording layer)
The setting of the recordable range of the second recording layer 104 by the optical disc device of the present embodiment will be described. The recording of data on the optical disc 301 is performed in block units, and one block is composed of 16 sectors.

  FIG. 6A shows a case where the recording of the first recording layer 102 ends in block units. FIG. 6B shows a waveform of a reproduced signal from the second recording layer 104 in the state shown in FIG.

  The block 401 is an error correction block composed of 16 sectors and added with a code for detecting and correcting a signal error during signal reproduction. The sector group 404 is a recorded sector on which data is recorded, and the sector group 405 is an unrecorded sector on which no data is recorded.

  In FIG. 6A, since the entire area of the first recording layer 102 is recorded, the power of the laser beam reaching the second recording layer 104 is constant over the entire area. The distortion based on the recording state of the first recording layer 102 does not occur in the reproduction signal waveform. Therefore, when recording the second recording layer 104, there is no problem if recording is performed at any radial position. Therefore, the optical disc apparatus sets the entire area on the second recording layer 104 as the recordable area 403. Note that the recordable area 403 of the second recording layer is the entire area even when the first recording layer 102 has not been recorded in the entire area.

  Next, as shown in FIG. 7A, in the case where the unrecorded area in the first recording layer 102 is a few sectors remaining and becomes very small so as not to satisfy one block, the second recording layer 104 The setting of the recording range will be described. The entire area of the second recording layer is unrecorded. In FIG. 7A, the unrecorded area 405 of the first recording layer 102 has six sectors (less than one block).

  Since recording is performed in units of blocks, as shown in FIG. 7A, if the unrecorded sector 405 becomes the remaining six sectors and is less than one block, further recording cannot be performed in the first recording layer 102. . That is, the first recording layer 102 cannot record completely up to the outermost periphery. Therefore, the data is moved to the second recording layer 104 to perform data recording. However, since the recorded sector 404 and the unrecorded sector 405 are mixed in the first recording layer 102, the recording state may be different. There is a problem that a difference occurs in the power of the laser beam 402 reaching the second recording layer 104, and distortion may occur in a reproduced signal waveform.

  Therefore, the optical disc device limits the recordable range 403 of the second recording layer 104 to the same range (the area within the same radius) as the recording range of the first recording layer 102. The recordable range 403 is determined without depending on the state of recording / unrecording of the second recording layer 104. As a result, in the second recording layer 104, data is recorded only in a range where the power of the laser beam 402 is constant, so that the influence of the distortion of the reproduction signal waveform can be reduced. Normally, the unrecorded portion of the first recording layer 102 does not become less than one block, but for example, the next sector is used because a defective sector affected by scratches or dust is detected during the recording operation. For example, when the sector is not used as scheduled, the unrecorded sector may occur at the final stage of recording.

  Since the recordable range of the second recording layer 104 is determined as described above, the optical head 303 of the optical disc device moves from the inner periphery to the outer periphery of the optical disc when recording on the first recording layer 102, and When the recording of the recording layer is completed, the recording of the second recording layer 104 is started from that position.

  It should be noted that instead of setting the recordable range 403 of the second recording layer 104 to the same range as the range where recording was performed on the first recording layer 102, as shown in FIG. The recordable range 403 of 104 may be set to an area inside the recording area of the first recording layer 102. For example, the outer peripheral position of the recording area of the second recording layer 104 is shifted from the outermost periphery of the recording area of the first recording layer 102 to the first recording layer when the laser beam is focused on the second recording layer. (See FIG. 8 (b)). By determining the recording area of the second recording layer 104 in this manner, it is possible to eliminate the influence of the nonuniformity of the transmittance at the end of the recording area of the first recording layer 102 with respect to the second recording layer 104, and to achieve a stable operation. Recording becomes possible.

  Next, an operation of recording the second recording layer 104 after the recording of the first recording layer 102 is completed will be described. The defect list area 108 is used to transmit information on the recording range of the first recording layer 102 to the second recording layer 104. The defect list area 108 is an area secured in the inner peripheral portion of the disk for recording defect information of a sector.

  First, when the recording of the first recording layer 102 is completed, the optical head 303 moves to the defect list area 108 and, according to an instruction from the CPU 309, the innermost sector and the outermost periphery of the recording area 501 of the first recording layer 102. Is recorded in the defect list area 108.

  The recordable area 403 of the second recording layer 104 converts the address information of the recording area 501 of the first recording layer 102 read from the defect list area 108 into position information of the optical head 303, Data recording is performed by determining a range in which the recording layer 104 is irradiated with the laser beam 402. The information in the recording area 501 of the first recording layer 102 may be recorded in the defect list area 112, the spare area 109, or the spare area 113. Further, an area for recording only the information of the recording area 501 may be newly provided. Further, the recording may be started from any position as long as the recording start position of the second recording layer 104 is within the range of the recordable area 403. Further, the recording of the recordable area 403 may be started with the position of the optical head where the recording is completed in the first recording layer 102.

  As described above, by recording the dummy data in the area where data is not normally recorded in the sector, the dispersion of the transmittance in the recording layer is eliminated, and the power of the laser beam reaching the other layer is made uniform. Further, by limiting the recordable range of the other layer, recording / reproduction can be performed under more stable conditions.

4. Modification Example The method for determining the recordable area 403 of the recording layer 104 in the above-described embodiment is an example, and the light of the recording layers 102 and 104 is focused on the recording layer 104 at the same radial position after reproducing the recording area 501. Other means may be used as long as the heads have the same positional relationship.

  In this embodiment, when data is overwritten on the first recording layer 102 and the recording area 501 is enlarged, the recordable range 403 is also enlarged. When the entire area of the recording layer 102 is recorded by overwrite recording, the recording range of the second recording layer 104 is not limited.

  Further, in the present embodiment, if the range overwritten on the first recording layer 102 is within the range of the recording area 501 before overwriting, the recordable area 403 on the second recording layer 104 does not change. However, the recording of the second recording layer 104 may be started from the position of the optical head at the end of the overwriting of the first recording layer 102.

  In the above-described embodiment, the positional relationship on the outer peripheral side of the recording areas of the first and second recording layers 102 and 104 has been described, but the inner peripheral side has the innermost of the recordable area of the second recording layer 104. The radius of the circumference may be set to be equal to or larger than the radius of the innermost circumference of the recording area of the first recording layer 102. As a result, the laser beam that reaches the second recording layer 104 always passes through the recordable area of the first recording layer 102 and is transmitted.

  Also, data recording is started from the second recording layer 104, and recording to the first recording layer 102 is started after the recording of the second recording layer 104 is completed. Similarly, the recordable area of the first recording layer 102 is limited to be equal to or larger than the recording area of the second recording layer 104 (preferably, the recordable area of the first recording layer 102 is limited). The area is set to be larger than the recording area of the second recording layer 104. That is, the laser beam always passes through the recordable area of the first recording layer 102 and reaches the second recording area 104. The outermost and innermost radii of the recording area of the first recording layer 102 are determined as follows. The radius of the outermost circumference of the recordable area of the first recording layer 102 is set to be equal to or larger than the radius of the outermost circumference of the recording area of the second recording layer 104, and the radius of the innermost circumference of the recordable area of the first recording layer 102 Is set to be equal to or less than the innermost radius of the recording area of the second recording layer 104.

  INDUSTRIAL APPLICABILITY The present invention can be applied to an optical disc device that records information on an optical disc capable of optically recording / reproducing information, particularly a multilayer optical disc having a plurality of recording layers, and reaches a recording layer far from a laser light source. The power of the laser beam can be made uniform, and recording and reproduction can be performed under more stable conditions.

1 is a block diagram of an optical disk device according to the present invention. FIG. 1 is a structural diagram of an optical disk on which information is recorded / reproduced by an optical disk device according to the present invention (A) A diagram illustrating a wobble shape indicating a signal “0” when the address information is included in the wobble shape in which the track is meandering, and (b) a signal when the address information is included in the wobble shape in which the track is meandering. A diagram illustrating a wobble shape indicating “1”, and (c) a diagram illustrating address information configured by combining wobble shapes indicating signals “0” and “1”. (A) A diagram showing a state of the first recording layer 102 on which data is appropriately recorded by a method without performing dummy recording, and (b) a second recording corresponding to the first recording layer shown in (a). Diagram showing the waveform of the reproduced signal obtained when reproducing the layer (A) A diagram showing a state of a first recording layer on which dummy data is recorded. (B) Reproduction obtained when reproducing a second recording layer corresponding to the first recording layer shown in (a). Diagram showing signal waveform (A) A diagram for explaining the recordable range of the second recording layer when there is no unrecorded sector in the first recording layer, and (b) a diagram from the second recording layer in the case shown in (a). Diagram showing playback signal waveform (A) A diagram for explaining the recordable range of the second recording layer when the first recording layer has an unrecorded sector, (b) Reproduction from the second recording layer in the case shown in (a) Diagram showing signal waveform (A) A diagram for explaining the recordable range of the second recording layer, (b) A diagram for explaining the recording end position of the first recording layer and the recording start position of the second recording layer FIG. 7 is a diagram for explaining the effect of the optical characteristics of the first recording layer on the laser beam reaching the second layer. FIG. 4 is a diagram showing optical characteristics of a first recording layer.

Explanation of reference numerals

102 first recording layer 104 second recording layer 107 lead-in area 108 defect list area 109 spare area 110 data area 115 sector 116 address area 117, 119 gap area 118 test emission area 120 user data area 121 buffer area 201 address information 202 Recording data 203 Dummy data 300 Optical disk drive 301 Optical disk

Claims (21)

An optical information recording method for recording data on an optical disc having a plurality of recording layers capable of optically recording information,
The optical disc has a first recording layer, and a second recording layer disposed on a side farther from the light source than the first recording layer,
When data is recorded on the second recording layer, the outermost radius of the data recordable range of the second recording layer is set to the outermost radius of the area where data is recorded on the first recording layer. A method for recording optical information, comprising:   The spiral direction of the track structure is alternately reversed for each recording layer and the recording direction is different, and the position of the optical head after the end of the data recording of the first recording layer is set as the recording start position of the second recording layer. The method for recording optical information according to claim 1, wherein: The optical disc has data recorded in predetermined block units,
When the unrecorded area of the first recording layer becomes smaller than the size of one block during the data recording operation of the first recording layer, the recording to the unrecorded area is not performed and the second recording layer is not recorded. 2. The method for recording optical information according to claim 1, wherein the data recording layer is switched to a recording layer.   4. The method according to claim 3, wherein the outermost radius of the recordable area of the second recording layer is smaller than the outermost radius of the data recording area of the first recording layer by a predetermined amount. Method of recording optical information.   2. The optical device according to claim 1, wherein an innermost radius of a data recordable area of the second recording layer is equal to or larger than an innermost radius of a data recording area of the first recording layer. How information is recorded.   The method according to claim 1, wherein an innermost radius of a data recordable range of the second recording layer is set to a value larger by a predetermined amount than an innermost radius of a data recording area of the first recording layer. Item 4. The method for recording optical information according to Item 1. An optical information recording method for recording data on an optical disc having a plurality of recording layers capable of optically recording information,
The optical disc has a first recording layer, and a second recording layer disposed on a side farther from the light source than the first recording layer,
A method for recording optical information, characterized in that the optical disc has a track divided into a plurality of sectors, each sector includes a buffer area at the end, and predetermined dummy data is recorded in the buffer area.   The sector further includes an address area including a sector identification signal, a user data area disposed before the buffer area and recording data, and a gap area provided between the address area and the user data area. The method for recording optical information according to claim 7, comprising:   9. The optical information recording method according to claim 8, wherein dummy data is recorded in all of the gap area and the buffer area.   9. The optical information recording method according to claim 8, wherein dummy data is recorded in a part of the gap area and the buffer area.   9. The optical information recording method according to claim 8, wherein the dummy data is not recorded in the gap area or the area in the buffer area near the boundary with the address area.   9. The optical information recording method according to claim 8, wherein the dummy data is the same as a synchronization signal recorded at the beginning or end of the user data area. The sector has a user data area for recording data before the buffer area,
Dummy data in the buffer area is recorded at a predetermined distance from data recorded at the end of the user data area,
8. The optical information according to claim 7, wherein the predetermined distance is a length within two times a maximum mark length determined by the modulation rule when the data is recorded according to a predetermined modulation rule. Recording method.   14. The optical information recording method according to claim 13, wherein the predetermined distance is longer than a minimum mark length determined by the modulation rule. An optical information recording apparatus for recording data on an optical disc having a plurality of recording layers capable of optically recording information, wherein the optical disc has a first recording layer and a light source that is more than the first recording layer. And a second recording layer disposed on the far side.
The recording apparatus includes: an optical head that irradiates a laser beam for recording information on the optical disk; a drive control unit that drives the optical head; and a control unit that controls the drive control unit.
When data is recorded on the second recording layer, the control means sets the radius of the outermost periphery of the data recordable range of the second recording layer to an area where data is recorded on the first recording layer. An optical information recording apparatus, wherein the control is performed so as to be equal to or smaller than the outermost radius of the optical information. The optical disc has data recorded in predetermined block units,
During the data recording operation of the first recording layer, when the unrecorded area of the first recording layer becomes smaller than the size of one block, recording to the unrecorded area is not performed and the second recording layer is not recorded. 16. The optical information recording device according to claim 15, wherein a data recording layer is switched to a recording layer.   17. The system according to claim 16, wherein the outermost radius of the recordable area of the second recording layer is smaller than the outermost radius of the data recording area of the first recording layer by a predetermined amount. Optical information recording device.   16. The optical device according to claim 15, wherein an innermost radius of a data recordable range of the second recording layer is equal to or larger than an innermost radius of a data recording area of the first recording layer. Information recording device.   The method according to claim 1, wherein an innermost radius of a data recordable range of the second recording layer is set to a value larger by a predetermined amount than an innermost radius of a data recording area of the first recording layer. Item 16. An optical information recording device according to Item 15. What is claimed is: 1. An optical information recording method for recording data on an optical disc having a plurality of optically recordable recording layers, wherein the optical disc is a first recording layer and a light source more than the first recording layer. A second recording layer disposed on the far side, further comprising a track divided into a plurality of sectors, each sector including a buffer area at the end,
The recording apparatus includes: an optical head that irradiates a laser beam for recording information on the optical disc; a drive control unit that drives the optical head; and a control unit that controls the drive control unit.
The recording device for optical information, wherein the control means controls to record predetermined dummy data in the buffer area. The sector further includes an address area including a sector identification signal, a user data area disposed before the buffer area and recording data, and a gap area provided between the address area and the user data area. The optical information recording apparatus according to claim 20, comprising:

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