JP3576121B2 - Optical disk and information recording / reproducing device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical disk having multiple recording / reproducing layers and an information recording / reproducing apparatus capable of recording / reproducing information on / from the optical disk.
[0002]
[Prior art]
As a technique for increasing the capacity of an optical disc, there is a two-layer technique in which a recording / reproducing layer is stacked in two layers, which can increase the capacity per unit area to about twice.
[0003]
As a product of an optical disk employing this technology, there is a single-sided, dual-layer DVD for reproduction (a digital versatile disk (DVD) having two layers of information recording surface and readable from one side), and has a storage capacity of 8. It is as large as 54 GB. DVD is a read-only optical disk, but also for recording / reproducing recording / reproducing optical disks, presentations at conferences on two-layer technology have been made, and a promising technology that can increase the capacity without changing large hardware such as a light source. It is believed that.
[0004]
In the case of a two-layer disc, the distance from the substrate surface is different between the first layer and the second layer because the recording / reproducing layer exists in two layers. For this reason, there is a so-called interlayer crosstalk in which information from one layer leaks when information of one layer is reproduced. Interlayer crosstalk depends on the interlayer distance of the recording / reproducing layer, and the effect is reduced as the interlayer distance is increased. However, if the interlayer distance is large, the difference in distance from the substrate surface to each layer increases, and spherical aberration increases. Conversely, there is a trade-off that when the interlayer distance is reduced, interlayer crosstalk increases. For this reason, it is necessary to design the interlayer distance within a range of an allowable spherical aberration amount.
[0005]
In the current standard for single-sided, dual-layer DVD discs, the interlayer distance is 55 μm ± 15 μm. Although the spherical aberration increases due to the two-layer structure, the specification is determined so that the increase amount falls within the range of the specification of the optical aberration amount which is allowed and the range where the influence of interlayer crosstalk is allowed. I have.
[0006]
FIGS. 1A, 1B, and 1C are views showing the state of a light spot irradiated on the other layer when reproducing data of one layer of the two-layer structure.
[0007]
When the beam spot 102 (FIG. 1B) is focused on the recording / reproducing layer L0 (FIG. 1A), as shown in FIG. 1) (FIG. 1A) is sufficiently large with respect to the recording pit.
[0008]
The reflected light of the spot 104 leaks into the reproduction signal. However, when pits are recorded in advance over the entire area such as a DVD-ROM, crosstalk from other layers is an average DC. Since it is the light amount of the (DC) component and the leakage amount is almost the same in any region, the influence on the reproduction signal is as small as possible.
[0009]
On the other hand, in a recording / reproducing optical disk, ID information such as a physical address is recorded in advance for each information unit in order to determine where to perform recording and reproduction when recording and reproducing data. Usually, the ID information is not a record mark that can be erased from the viewpoint of reliability and stability, but often cannot be erased and is recorded on the substrate of the optical disc in the form of embossed prepits. For example, FIG. 13 schematically shows the physical structure of a DVD-RAM. In the DVD-RAM, address information is recorded as embossed prepits on the substrate of an optical disc with respect to information in sector units. The ID information is radially aligned within the recording zone from the viewpoint of reducing crosstalk.
[0010]
Further, there is a tracking guide groove called a groove, and data is recorded in a region between groove tracks called a groove track 1301 or a land track 1302. The data area where data is recorded is an area where a groove exists, and the ID information area is an area where the groove is divided, so that these areas have different average reflectances. Apart from the above, there has been proposed a method in which a groove is not divided and information is recorded between a land and a groove.
[0011]
In this method, since the groove is not divided, the reflectivity between the ID information area and the data area is almost the same before data is recorded.
[0012]
However, since data is not always recorded in the ID information area, when data is recorded in the data area, the average reflectivity of the data area changes (usually, the reflectivity decreases). A difference occurs in the reflectance between the two.
[0013]
[Problems to be solved by the invention]
In a recording / reproducing optical disk having a recording / reproducing layer having a physical format structure in which ID information is radially aligned as described above, the following problem occurs when the recording / reproducing layer is made into two layers.
When a light spot is condensed on a certain layer and data in that layer is reproduced, crosstalk occurs due to the reflected light of the light spot irradiating the other layer.
[0014]
During data reproduction, as shown in FIG. 2A, when the light spot 104 irradiating another layer scans the boundary between the recording data area and the ID information area, the recording data area and the ID Since the DC component of the amount of reflected light differs in the information area, the amount of crosstalk at that time greatly fluctuates.
[0015]
Therefore, there is a problem that a reproduced signal locally causes a DC fluctuation due to crosstalk, which adversely affects data reproduction.
[0016]
Accordingly, an object of the present invention is to provide an optical disc capable of suppressing local DC fluctuation due to crosstalk from another layer in a recording / reproducing optical disc having a two-layer structure in view of the above problems.
[0017]
[Means for Solving the Problems]
The optical disc of the present invention includes a plurality of recording / reproducing layers, each of which has a land track and a groove track, and one or a plurality of sector-based recording data areas on the land track and the groove track. An optical disc which has an ID information area recorded in advance so as to correspond thereto and performs data recording and reproduction on at least one of these land tracks and groove tracks by utilizing a change in reflectance of a recording mark.A reflectance control area is provided for the ID information area so as to be arranged in a radial direction of the optical disk, and the ID information area and the reflectance control area are alternately arranged in the radial direction. The track is divided every other track as the ID information area, and the divided part becomes a land. Embossed prepits are formed at the boundary between the land and the adjacent land track, and the embossed prepits are arranged in the radial direction. The land track and the groove track located between the pits are set as the reflectance control areas in which the reflectance is lower than that of the land.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0019]
FIGS. 3A, 3B, and 4 are views showing the physical structure of the first optical disk according to the embodiment of the present invention.
[0020]
3A and 3B are views of the optical disk viewed from a cross section. The recording / reproducing layer has two layers, L0 and L1. When reproducing or recording a signal, the recording / reproducing device irradiates a laser beam from one surface of the disk, focuses on a layer to be reproduced by the objective lens 301, and tracks along a guide groove on the optical disk. Then, data can be reproduced by photoelectrically converting the light reflected from the disk. The laser light is modulated by controlling the laser light source based on the recording information, and the recording layer is irradiated with the laser light, whereby information can be recorded on the recording layer.
[0021]
FIG. 4 is a schematic diagram when the physical structure of the recording / reproducing layer of this optical disc is viewed from the surface. This is a so-called land / groove recording type optical disc in which recording marks 403 are recorded on both the groove track 401 and the land track 402. The recording film is composed of a phase change film. The recording film is irradiated with laser light to modulate light intensity. In the recording film, a region where the irradiation light power is strong changes from a crystalline state to an amorphous state, and a recording mark 403 is formed. The difference in the amount of reflected light between the crystalline region and the amorphous region is different, and a reproduction signal is obtained by determining the recording mark based on the intensity of the reflected light.
[0022]
It is necessary to obtain a physical position on the optical disc for controlling recording or reproduction of information on the optical disc. For this purpose, an ID information area is provided as shown in FIG. 4, and ID information 404 is recorded on the disc in advance as emboss prepits.
[0023]
Between the data area and the ID information area, a reflectance control area having a constant width, which is a feature of the present invention, is provided. The physical shape of the reflectance control area is the same land / groove structure as the data area. Thus, mark recording is possible in the same manner as recording information in the data area.
[0024]
In the reflectance control area, a long amorphous mark different from the pattern of the modulation method used for recording user data is recorded on both the land track and the groove track.
[0025]
Next, the effects of the present invention will be described.
[0026]
In a two-layer disc, the physical shape of the substrate differs between the data area and the ID information area. For this reason, as shown in FIG. 2, when the light spot irradiating the other layer scans the place where the data area changes from the data area to the ID information area, the DC component of the reproduced signal locally largely changes. As a result, the DC component of the amount of crosstalk from another layer largely changes locally, which adversely affects the reproduced signal.
[0027]
In the optical disc of the present invention, the reflectance control area is provided before and after the ID information area in the track tangential direction, and the average reflectance of the reflectance control area can be changed by a normal amorphous mark.
[0028]
For example, in FIG. 4, since the ID information area has more lands than the data area having the land / groove structure, the reflectance is generally higher. For example, in the case of a type of phase change optical disk in which the reflectance of the amorphous portion is lower than the reflectance of the crystal portion, most of the reflectance control regions between the data region and the ID information region are made to be amorphous portions. The average reflectance of this area can be made lower than that of the data area.
[0029]
That is, when a light spot is condensed on a certain layer and the light spot irradiated on the other layer during recording and reproduction of information has a large spot diameter as shown in FIG. The quantities are average DC quantities. In the present invention, when the light spot irradiated to the other layer scans near the boundary between the data area and the ID information area, it passes through a reflectance control area having a low reflectance. As shown in FIG. 5B, it is possible to reduce the variation in the amount of crosstalk given to the reproduction signal. FIG. 5A shows a conventional variation in the amount of crosstalk.
[0030]
In this embodiment, the case where the ID information in the ID information area is recorded as embossed prepits on the land where the groove is divided has been described. However, the same effect can be obtained even when the groove is not divided and the ID information is recorded on the boundary between the land track and the adjacent groove track.
[0031]
FIG. 6 shows an example in which the present invention is applied to a case where a groove is not divided and ID information is recorded at a boundary between a land track and an adjacent groove track.
[0032]
In the ID information area, since the disc has a land / groove structure, unlike the case of embossed prepits, there is not much difference in the average reflectance between the data area and the ID information area due to the physical structure.
[0033]
However, when a recording mark is recorded in the data area, the average reflectance of the data area changes (usually decreases) by the amount of the amorphous recording mark. As a result, the ID information area is always in a crystalline state without recording marks, and the data area and the ID information area have different average reflectances.
[0034]
Therefore, when a light spot on another layer scans near the boundary between the data area and the ID information area on a two-layer disc, the DC (direct current) component of the reflectance greatly changes locally in the data area and the ID information area. I do. As a result, the DC component of the amount of crosstalk from another layer largely changes locally, which adversely affects the reproduced signal.
[0035]
Therefore, in the present invention, by providing the reflectance control area as shown in FIG. 6, it is possible to reduce the variation in the amount of crosstalk given to the reproduced signal by the same effect.
[0036]
In FIGS. 4 and 6, a recording area having a fixed width is provided at a position continuous with both ID information areas in which ID information is recorded in the track tangential direction, and the recording area controls the average reflectance in the area. Area for controlling the reflectance. However, it is needless to say that the reflectance control area may be one of the front and rear of the ID information area.
[0037]
FIG. 7 is a diagram illustrating a physical structure of the second optical disc according to the embodiment of the present invention. Similar to the first embodiment, this is a land / groove recording type two-layer structure phase-change optical disc. The land track 702 is continuous in the ID information area. Groove track701Is divided every other track in the ID information area, and here is a land area.To.
[0038]
The emboss pre-pit 704 is located at the boundary between the land where the groove track 701 is divided and the land track 702. In this example, the embossed prepits are located one at a time in the radial direction when the land / groove track is a set, and are aligned in the radial direction.
[0039]
In the present embodiment, the ID information area and the reflectance control area are alternately arranged in the radial direction, and the area adjacent to the ID information area among the tracks adjacent to the ID information area becomes the reflectance control area. It is located in.
[0040]
In the reflectance control area, the average reflectance of this area can be changed by a normal amorphous recording mark. FIG. 7 shows a case where a long amorphous mark 705 is recorded.
[0041]
In FIG. 7, since the ID information area has many lands, the reflectivity of the ID information area is generally higher than the data area of the land / groove structure. However, in the present invention, as in the first embodiment, in the case of a phase change optical disk of a type in which the reflectance of the amorphous portion is lower than that of the crystal portion, most of the reflectance control region is made to be the amorphous portion. Can be made lower than the data area.
[0042]
In the present embodiment, by arranging the ID information area and the reflectance control area alternately in the radial direction, when a light spot is condensed on one layer and information is recorded and reproduced, the ID spot is recorded on another layer. When the irradiated light spot scans the vicinity of the boundary between the data area and the ID information area, it is possible to reduce the variation in the average amount of reflected light as compared with the first embodiment. As a result, it is possible to further reduce the variation in the crosstalk amount given to the reproduction signal.
[0043]
That is, a recording area having a constant width is provided adjacent to at least one or both of the tracks adjacent to the ID information area where the ID information is recorded, and this recording area has a reflectance for controlling the average reflectance in the area. This is a control area.
[0044]
FIG. 8 shows still another embodiment. Also in this embodiment, similarly to FIG. 6 of the first embodiment, the effect of the present invention can be obtained even when the groove is not divided and the ID information is recorded at the boundary between the land track and the adjacent groove track. Obtainable. 801 is a groove track, 802 is a land track, 803 is a recording mark in a data area, and 804 is an ID information area. In this ID information area 804, a reflectance control area is formed by an amorphous mark 805.
[0045]
In this case, since the ID information area has the same land / groove structure as the data area, unlike the case of embossed prepits, there is not much difference in reflectivity due to the physical structure, and the recording mark is recorded in the data area. There is a difference in the reflectance between the data area and the ID information area due to the presence of.
[0046]
According to the present invention, by controlling the average reflectance of the reflectance control area, it is possible to suppress the average reflectance difference between the data area and the ID information area. In addition, it is possible to reduce the variation in the amount of crosstalk given to the reproduction signal.
The present embodiment can be applied in various forms.
[0047]
In the second embodiment, the case where the ID information area and the reflectance control area are alternately arranged in the radial direction of the optical disc has been described. However, in the optical disc, the ID information area is not arranged intermittently but in the radial direction. There is a case where they are arranged in a continuous state and in an aligned state.
[0048]
In this case, by arranging the ID information area and the reflectance control area in a staggered manner as shown in FIGS. 9 and 10, it is possible to realize the arrangement of the ID information without impairing the effect of the present invention. is there.
[0049]
In FIG. 9, reference numeral 901 denotes a groove track; 902, a land track; 903, a recording mark in a data area; and 904, an ID information area. In the ID information area 904, a reflectance control area is formed by an amorphous mark 905.
[0050]
10, 1001 is a groove track, 1002 is a land track, 1003 is a recording mark in a data area, and 1004 is an ID information area. In this ID information area 1004, a reflectance control area is formed by an amorphous mark 1005.
[0051]
FIG. 9 shows an example in which the ID information in the ID information area 904 is recorded as embossed prepits on the land where the groove is divided, and the ID information in the ID information area 1004 in FIG. In this example, ID information is recorded at a boundary between a land track and a groove track adjacent to the land track.
[0052]
11 and 12, similarly to FIGS. 7 and 8, the ID information area and the reflectance control area are alternately arranged in the radial direction of the optical disk, and among the tracks adjacent to the ID information area, This is an example of an optical disc in which a region adjacent to the optical disk is arranged so as to be a reflectance control region, and further, an address information region and a reflectance control region are alternately arranged in a track tangential direction.
[0053]
In FIG. 11, 1101 is a groove track, 1102 is a land track, 1103 is a recording mark in a data area, 1104, 1105, and 1106 are ID information areas (emboss pre-pits).
[0054]
In FIG. 11, a reflectance control area 1108 is provided in the middle of a data area 1107 corresponding to the emboss pre-pit 1104, and is arranged at a position adjacent to the address information areas 1105 and 1106 of both adjacent tracks.
[0055]
In this case, as compared with the case shown in FIG. 9, the ID information area can be divided into two locations, and the width of the ID information area per location can be shortened. As a result, it is possible to further reduce the amount of change in the amount of crosstalk applied to the reproduction signal.
[0056]
FIG. 12 shows an example in which the groove is not divided in FIG. 11 and the ID information is recorded at the boundary between the land track and the adjacent groove track, and the effect of the present invention can be obtained similarly.
[0057]
Reference numeral 1201 denotes a groove track; 1202, a land track; 1203, a recording mark in a data area; and 1204, an ID information area. In this ID information area 1204, a reflectance control area is formed by an amorphous mark 1205.
[0058]
In the above embodiment, a case was described in which a very long amorphous mark different from the pattern of the modulation method used for recording data is also recorded on the land / groove. A repeating pattern of a mark and a short space may be used. In this case, the reflectance can be controlled using a circuit for generating a recording pulse. Further, as long as an amorphous area having a shape such that the average reflectance can be controlled can be generated in the reflectance control area, it is not necessary to stick to a normal recording mark.
[0059]
Although the case where the embossed prepit structure is also circular has been described, the effects of the present invention can be naturally obtained with other shapes.
[0060]
In the present embodiment, a land / groove recording type phase change optical disc has been described. However, the present invention can be similarly applied to a case where recording is performed only on lands or grooves.
[0061]
Next, an example of the information recording / reproducing apparatus for the optical disc will be described.
[0062]
As shown in FIG. 14, this information recording / reproducing apparatus has a disk drive unit 20 that rotates and drives an optical disk 10 as a first medium and executes reading and writing of information. Further, a hard disk drive unit HDD that drives a hard disk as a second medium is provided. The data processor unit 21 can supply recording data to the disk drive unit 202 and the hard disk drive unit HDD, and can receive reproduced signals. The disk drive unit 20 has a rotation control system for the optical disk 10, a laser drive system, an optical system, and the like.
[0063]
The data processor 21 handles data in units of recording or reproduction, and includes a buffer circuit, a modulation / demodulation circuit, an error correction unit, and the like.
[0064]
The recording / reproducing apparatus mainly includes an encoder unit 50 constituting a recording side, a decoder unit 60 constituting a reproducing side, and a microcomputer block 30 for controlling the operation of the apparatus main body.
[0065]
The encoder unit 50 includes a video and audio analog-to-digital converter for digitizing the input analog video signal and the input analog audio signal, a video encoder, and an audio encoder. Furthermore, it also includes a sub-picture encoder. The output of the encoder unit 50 is converted into a predetermined DVD-RAM format by a formatter 51 including a buffer memory and supplied to the data processor unit 21.
[0066]
An external analog video signal and an external analog audio signal from the AV input unit 41 or an analog video signal and an analog audio signal from a TV (television) tuner 42 are input to the encoder unit 50.
[0067]
The digital video signal or digital audio signal that has been converted from analog to digital can be directly supplied to the video mixing unit 71 and the audio selector 76.
[0068]
In the video encoder, 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 or a digital audio signal of linear PCM based on the MPEG or AC-3 standard.
[0069]
When the sub-picture information is input from the AV input unit 41 (for example, a signal from a DVD video player with an independent output terminal for the sub-picture signal), or a DVD video signal having such a data structure is broadcast, and the broadcast is transmitted to the TV tuner 42. , The sub-picture signal in the DVD video signal is encoded (run-length compressed) by the sub-picture encoder, and becomes a bit map of the sub-picture.
[0070]
The encoded digital video signal, digital audio signal, and sub-picture data are packed in the formatter 51 to become a video pack, an audio pack, and a sub-picture pack, and these are aggregated to form a DVD-recording standard (eg, DVD-RAM). , DVD-R, DVD-RW, etc.).
[0071]
Here, the present apparatus supplies the information (packs of video, audio, sub-picture data, etc.) formatted by the formatter 51 and the created management information to the hard disk drive HDD via the data processor 21. However, it can be recorded on a hard disk (or optical disk 10). Also, information recorded on the hard disk (or the optical disk 10) can be recorded on the optical disk 10 via the data processor unit 21 and the disk drive unit 1002.
[0072]
Further, editing processing such as partially deleting video objects of a plurality of programs recorded on the hard disk or the optical disk 10 and connecting objects of different programs can be performed.
[0073]
The microcomputer block 30 includes an MPU (microprocessing 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. .
[0074]
The MPU of the microcomputer block 30 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. I do.
[0075]
The microcomputer block 30 includes an information processing unit necessary for controlling the entire system, and includes a work RAM, a directory detection unit, a VMG (whole video management information) information creation unit, a copy-related information detection unit, A copy and scrambling information processing unit (RDI processing unit), a packet header processing unit, a sequence header processing unit, and an aspect ratio information processing unit are provided.
[0076]
Of the execution results of the MPU, the contents to be notified to the user are displayed on the display unit 43 of the DVD video recorder, or displayed on the monitor display by OSD (on-screen display). Further, the microcomputer block 30 has a key input unit 44 for giving an operation signal for operating this device.
[0077]
The timing at which the microcomputer block 30 controls the disk drive unit 1002, the hard disk drive unit 20, the data processor unit 21, the encoder unit 50 and / or the decoder unit 60, etc. is based on time data from the system time clock (STC) 38. Can be performed based on Recording and playback operations are normally performed in synchronization with the time clock from the STC 38, but other processing may be performed at a timing independent of the STC 38.
[0078]
The decoder unit 60 includes a separator for separating and extracting each pack from a DVD format signal having a pack structure, a memory used for performing pack separation and other signal processing, and main video data (for a video pack) separated by the separator. A V-decoder that decodes the content, an SP decoder that decodes the sub-picture data (contents of the sub-picture pack) separated by the separator, and an A-decoder that decodes the audio data (contents of the audio pack) separated by the separator. Have. The video processor further includes a video processor that appropriately combines the decoded main video data with the decoded sub video data, and superimposes a menu, a highlight button, subtitles, and other sub video on the main video.
[0079]
The output video signal of the decoder unit 60 is input to the video mixing unit 71. The video mixing section 71 synthesizes text data. The video mixing section 71 is also connected to a line for directly taking in signals from the TV tuner 42 and the A / V input section 41. A frame memory 72 used as a buffer is connected to the video mixing unit 71. When the output of the video mixing unit 71 is a digital output, it is output to the outside via an interface (I / F) 73, and when it is an analog output, it is output to the outside via a digital-to-analog converter 74.
[0080]
The output audio signal of the decoder section 60 is converted to an analog signal by a digital-to-analog converter 77 via a selector 76 and output to the outside. The selector 76 is controlled by a select signal from the microcomputer block 30. Thus, when directly monitoring the digital signal from the TV tuner 41 or the A / V input unit 42, the selector 76 can directly select a signal that has passed through the encoder unit 50.
[0081]
Note that the formatter of the encoder unit 50 creates each segmentation information during recording and sends it to the MPU of the microcomputer block 30 periodically (information at the time of interruption of the GOP head). The segmentation information includes the number of VOBU packs, the end address of the I picture from the beginning of the VOBU, and the playback time of the VOBU.
[0082]
In addition, in the recording / reproducing DVD, one video file is used for one disk. In order to continue reproduction 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 performs recording in CDA units.
[0083]
The data processor unit 21 receives data in VOBU units from the formatter of the encoder unit 50 and supplies data in CDA units to the disk drive unit 20 or the hard disk drive unit HDD. Further, the MPU of the microcomputer block 30 creates management information necessary for reproducing the recorded data, and sends the created management information to the data processor unit 21 when recognizing a command to end data recording. Thus, the management information is recorded on the disc. Therefore, when encoding is being performed, the MPU of the microcomputer block 30 receives data unit information (such as segmentation information) from the encoder unit 50. At the start of recording, the MPU of the microcomputer block 30 recognizes the management information (file system) read from the optical disk and the hard disk, recognizes the unrecorded area of each disk, and changes the data recording area to the data processor unit 21. Through the disk is set.
[0084]
Here, an operation for recording a mark constituting the reflectance control area on the optical disk will be briefly described.
[0085]
As shown in FIG. 15, when the recording operation is started, it is determined whether or not the disc is a two-layer disc. In the case of a two-layer disc, a mark recording operation is performed on the reflectance control area. The recording layer is determined, the focus is adjusted, the disc management information is read, and the unrecorded area is recognized from the recorded address information (steps S1-S3). When the recording starts, it is determined whether or not the data recording position is the recording position before and after the ID information area. If it is a recording position before or after, a reflectance control mark is recorded in the reflectance control area (steps S4, S5, S6). If the data recording position is not before or after the ID information area, a data mark is recorded (step S7). Next, it is determined whether there is a recording stop command. If there is a recording stop command, the recording operation is stopped. If not, the recording data is prepared, and the process returns to step S5. That is, the apparatus of the present invention has means for recording a mark larger than the maximum length of the data mark as a reflectance control mark while data is being recorded in the recording data area.
[0086]
As described above, in the recording / reproducing apparatus according to the present invention, when data is recorded, a reflectance control mark is recorded in the reflectance control area. Thereby, when data is read or written in another layer, crosstalk from the ID information area of the layer on which data is recorded is suppressed.
[0087]
【The invention's effect】
As described above, according to the present invention, an area adjacent to the ID information area is used as a reflectance control area, and by controlling the reflectance of this area, a light spot is condensed on a certain layer in a two-layer disc, and information recording and information can be recorded. It is possible to suppress local DC fluctuation which occurs when a light spot irradiated on another layer during reproduction performs scanning near the boundary between the data area and the ID information area, and the crosstalk applied to a reproduction signal can be suppressed. Variations in volume can be reduced.
[Brief description of the drawings]
FIG. 1 is a diagram showing a light spot applied to another layer when reproducing data of one layer in an optical disc having a two-layer structure.
FIG. 2 is a diagram illustrating a change in the amount of crosstalk when a light spot irradiating another layer scans a boundary between a recording data area and an ID information area during data reproduction.
FIG. 3 is a cross-sectional view of an optical disc having a two-layer structure.
FIG. 4 is a diagram showing a physical structure of a first optical disc according to the embodiment of the present invention.
FIG. 5 is a view showing an effect of the first optical disc according to the embodiment of the present invention.
FIG. 6 is a diagram showing a physical structure of a first optical disc according to the embodiment of the present invention.
FIG. 7 is a diagram showing a physical structure of a second optical disc according to the embodiment of the present invention.
FIG. 8 is a diagram showing a physical structure of a second optical disc according to the embodiment of the present invention.
FIG. 9 is a diagram showing an application example of the second optical disc according to the embodiment of the present invention.
FIG. 10 is a diagram showing another application example of the second optical disc according to the embodiment of the present invention.
FIG. 11 is a diagram showing still another application example of the second optical disc according to the embodiment of the present invention.
FIG. 12 is a diagram showing still another application example of the second optical disc according to the embodiment of the present invention.
FIG. 13 is a schematic view showing a physical structure of a DVD-RAM.
FIG. 14 is an explanatory diagram of a configuration of an information recording / reproducing apparatus according to the present invention.
FIG. 15 is a flowchart shown to explain the operation of the characteristic part of the present invention in the information recording / reproducing apparatus of FIG. 14;
[Explanation of symbols]
101, 301: objective lens, 102: light spot focused on L0 layer, 103: information pit, 104, 204: light spot irradiated on L1 layer when reproducing L0 layer, 401, 601, 701, 801 , 901, 1001, 1101, 1201 ... groove track, 402, 602, 702, 802, 902, 1002, 1102, 1202 ... groove track, 403, 603, 703, 803, 903, 1003, 1103, 1203 ... recording mark, 404, 604, 704, 804, 904, 1004 ... ID information, 1104, 1105, 1106, 1204 ... ID information, 1108 ... Reflectance control area.

Claims (4)

A plurality of recording / reproducing layers are provided, and the recording / reproducing layers are pre-recorded so as to correspond to a land track and a groove track and a recording data area of one or more sectors on the land track and the groove track, respectively. An optical disc that includes a recorded ID information area and records and reproduces data on at least one of the land track and the groove track by using a change in the reflectance of a recording mark.
For the ID information area, a reflectance control area is provided so as to be arranged in the radial direction of the optical disc, and the ID information area and the reflectance control area are alternately arranged in the radial direction,
In addition, groove tracks are divided every other track as the ID information area, and the divided part becomes a land portion. Embossed prepits are formed at the boundary between this land portion and an adjacent land track, and are arranged in the radial direction. An optical disc, wherein land tracks and groove tracks located between the embossed pre-pits are set as the reflectance control areas whose reflectance is lower than that of the land portions . 2. The optical disk according to claim 1, wherein the optical disk is of a phase change type that performs recording and reproduction of information by utilizing a change in reflectance between amorphous and amorphous. 2. The optical disc according to claim 1, wherein the reflectance control area reduces the average reflectance by a recording mark. In an information recording apparatus that optically records information on an optical disc having a plurality of recording / reproducing layers and also reproduces information,
The recording / reproducing layer of the optical disc has a land track and a groove track, and an ID information area recorded in advance on the land track and the groove track so as to correspond to a recording data area of one or a plurality of sectors. Data is recorded and reproduced on at least one of the land track and the groove track by using a change in the reflectivity of a recording mark, and the data is recorded in the radial direction of the optical disc with respect to the ID information area. The ID information area and the reflectivity control area are alternately arranged in the radial direction, and groove tracks are divided every other track as the ID information area. And the divided portion becomes a land portion, and this land portion and the adjacent land track Embossed prepits are formed at the boundaries, and land tracks and groove tracks located between the embossed prepits arranged in the radial direction are set as the reflectance control areas in which the reflectance is lower than that of the land portions. ,
The information recording and reproducing device,
In the reflection control area, means for recording a mark larger than the maximum length of the data mark as a reflectance control mark during data recording in the recording data area is provided. Information recording / reproducing device.

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