TW201312554A - Replay method and replay device - Google Patents

Abstract

A recording medium having formed therein track groups having a plurality of adjacent information recording tracks formed using a shorter track pitch (Tp1) than a track pitch corresponding to an optical cutoff specified by the wavelength of an irradiated laser light and the NA of a radiating optical system. A track group pitch (TpG) of the track groups is longer than the track pitch corresponding to the optical cutoff. Difference signals for each radial contrast signal obtained by each reflected-light information for two replay laser spots radiated on the track groups are used as tracking error signals. At least one replay laser spot is made to be on-track on one of the information recording tracks and data is replayed from the reflected light information thereof, by tracking servo control using these tracking error signals.

Description

Regeneration method, regeneration device

The present invention relates to a reproducing method and a reproducing apparatus, and more particularly to a technique for performing appropriate reproduction on a recording medium for performing high-density recording by track pitch.

[Previous Technical Literature] [Patent Document]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2010-225237

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2010-244672

[Patent Document 3] Japanese Patent No. 4023365

[Patent Document 4] Japanese Patent Laid-Open Publication No. 2005-332453

Development of various discs and recordable discs (single readable and readable discs) in the category of CD (Compact Disc), DVD (Digital Versatile Disc), Blu-ray Disc (registered trademark), etc. Slices and rewritable discs).

For example, in the field of such optical discs, as a next-generation disc, further capacity increase due to high-density recording is required.

For example, as a directivity of high-density recording of a disc-shaped recording medium, it is conceivable to multilayer the recording layer, increase the recording density in the track line direction, and increase the recording density (small track pitch) in the track pitch direction, thereby Signal processing such as data compression processing, increase of recording capacity, and the like.

Among them, in the present invention, attention is paid to increasing the recording density in the track pitch direction.

For a disc, the laser spot is illuminated to the information track, and the data is reproduced based on the reflected light information. However, at this time, if the track pitch on the optical disk is narrower than the optical interception pitch, good reflected light information cannot be obtained. In particular, it is impossible to obtain information on the direction of tracking. For this reason, it is impossible to track the laser spot on the information track by tracking servo control.

Therefore, even if the narrow track pitch is not planned, it cannot be properly reproduced, and it cannot be established as a recording and reproducing system.

Here, the "pitch corresponding to optical occlusion" means the reciprocal of the spatial frequency of the optical occlusion, and the "pitch which is narrower than the optical severance" means the optical property corresponding to the pitch. The state where the spatial frequency is higher than the frequency of the occlusion space.

Therefore, as a high-density recording due to the narrow track pitch, when a high-density recording is performed with a recording medium having a track pitch narrower than the pitch corresponding to the optical cutoff, it is possible to provide appropriate tracking control. The method of reproducing the data and the reproducing device are preferred.

A reproducing method according to an embodiment of the present invention is a method for reproducing a recording medium, wherein the information recording track is optically interrupted by a ratio corresponding to a wavelength of the laser light to be irradiated and an NA of the illumination optical system. The track pitch is also a short track pitch, forming a track group adjacent to the plurality of tracks, and the track group spacing in terms of the aforementioned track group unit is a ratio equivalent The track spacing of the aforementioned optical occlusion is also long. Then, the complex orbits in the track group irradiate at least two reproducing laser spots, and the differential signals of the respective radial contrast signals obtained by the information of the reflected lights of the two reproducing laser spots are set as tracking errors. The signal is controlled by the tracking servo using the tracking error signal, and at least one or more reproducing laser spots are combined and controlled to fall on any information recording track, and the data is reproduced according to the reflected light information. .

A reproducing apparatus according to an embodiment of the present invention includes an optical head that is configured to provide an information recording track with an optically interrupted track pitch corresponding to a wavelength of a laser beam to be irradiated and an NA of an illumination optical system. a short track pitch, forming a track group adjacent to a plurality of tracks, and a track group pitch in terms of the above-mentioned track group unit is a recording medium longer than a track pitch corresponding to the optical cutoff, and is at least two reproducing thunder In the manner of irradiating the light spot, the laser light is irradiated through the object lens to obtain information about the reflected light of each laser spot; and the servo circuit portion is obtained by the information of each of the reflected light spots of the two reproducing laser spots. The differential signal of the comparison signal is set as a tracking error signal, and by using the tracking servo control of the tracking error signal, the optical head performs at least one or more reproducing laser spot to be combined and falls on any information record. The tracking operation on the rail; and the regenerative circuit unit regenerate based on the reflected light information of the reproducing laser spot that falls on the information track by the tracking control Material.

Further, the crosstalk canceling unit performs crosstalk canceling processing on the reflected light information of the reproducing laser spot that falls on the information recording track by the mesh control, and the reproducing circuit unit uses the crosstalk Offset The reflected light information of the crosstalk cancellation processing can also be used to reproduce data.

According to an embodiment of the present invention, in the recording medium, a track group adjacent to the plurality of tracks is formed at a track pitch shorter than a track pitch corresponding to the optical block, and further, a track group pitch ratio between adjacent track groups The track pitch equivalent to optical occlusion is also long. In other words, the track pitch is shortened in the track group, and the density in the track pitch direction is increased as a whole.

In addition, the track group pitch is a pitch when a track group formed by a plurality of tracks is determined as one track. That is, the distance between the central position in the radial direction when viewed from the entire track group and the same central position of the adjacent track group.

At this time, the track group is set to have a longer distance than the optical block, and the signal used for the tracking servo can be obtained from the periodic structure of the track group. Specifically, when at least two reproducing laser spots are irradiated to the complex orbits in the track group, radial contrast signals can be obtained as information of the respective reflected lights of the two reproducing laser spots. The differential signal of the radial contrast signal can be set as a tracking error signal for tracking servo control.

According to an embodiment of the present invention, the information recording track having a track pitch shorter than the track pitch corresponding to the optical occlusion is formed, and the tracking servo can be appropriately applied to the recording medium for realizing high-density recording. Thereby, a high-density recording and reproducing system can be realized.

Hereinafter, embodiments of the present invention will be described in the following order.

<1. Recording medium of the embodiment>

<2. Configuration Example of Disc Drive Device>

<3. Record reproduction method>

<4. High density due to narrow track pitch>

<5. Tracking method>

<6. Optical system structure example>

<7. Modifications>

<1. Recording medium of the embodiment>

The recording medium of the embodiment is, for example, a CD, a DVD, a Blu-ray Disc (BD) or the like, for example, a disc having a diameter of 12 cm.

Fig. 1 is a view showing an example of a cross-sectional structure of a recording medium (disc) 90 of the embodiment.

FIG. 1A discloses a configuration example in which the optical disk 90 has the substrate 93, the volume layer 91, and the cover layer 92. A recording layer (layer L0) is formed at a predetermined depth position in the volume layer 91. Further, the "depth" is the distance from the surface of the cover layer 92 in the thickness direction. The structure of this FIG. 1A is an example of a single layer disc of a single layer.

The surface side of the cover layer 92 is the incident surface of the laser light. The laser light is incident from the surface side of the cover layer 92, is focused on the layer L0, forms a spot, and is recorded or reproduced.

Fig. 1B shows an example of a multilayer disc in which a plurality of recording layers (layers L0...Ln) are formed in a volume layer. At this time, the laser light is incident from the surface side of the cover layer 92, and is focused on the target layer to form a light spot for recording or reproduction.

FIG. 1C is an example of setting a reference plane RL. Reference plane RL is for example A portion of the joint surface of the volume layer 91 and the cover layer 92.

This reference plane RL has a convex/concave rail configuration. For example, the groove is formed in a spiral shape, and is guided by the tracking of the information recording track formed on the layers L0 to Ln in the volume layer 91.

Furthermore, the reference plane RL is not a groove, and may be a concave rail row. Moreover, the concave track or the pit row is caused to oscillate (snake) according to the address information, and the absolute position information may be recorded.

Each example of Fig. 1 is only an example. As an example of the layer structure of the optical disk 90 of the embodiment, examples other than the above structures may be considered.

In the case of a single layer, it is not necessary to provide the volume layer 91 as in Fig. 1A. For example, the cover layer 92 is formed on the substrate 93, and the layer L0 may be formed on the joint surface of the substrate 93 and the cover layer 92.

Moreover, in the case of the multilayer disc of the multilayer of FIG. 1B and FIG. 1C, the volume layer 91 is a laminated film structure, and each layer L0...Ln may be formed in each laminated film. In the following, the layer L0 in the case of a single layer of the recording layer and the layer L0...Ln in the collective layer are collectively referred to as "layer L".

As the optical disc 90 of the embodiment, a reproduction-only disc and a recordable disc (single-readable disc or rewritable disc) are conceivable.

In the case of reproducing a dedicated disc, embossed pit rows are formed in each layer L. The embossed pit row may be formed by imprinting a stamper formed from a disc master for each layer L.

In the state of the optical disk 90 of the recordable type disc, laser light for recording is irradiated in a state where the recording device is rotationally driven, and a mark array in which information is recorded in the layer L is formed. As a marker, I want to change the phase Note, pigment change mark, interference mark mark, void (hole) mark, refractive index change mark, and the like.

At the time of reproduction of the optical disk 90, in the state where the optical disk 90 is rotationally driven by the reproducing device, the laser light for reproduction is irradiated to the layer L of the target of reproduction. Then, the reflected light information is detected in response to the pit train or the mark column formed in the layer L, and the data is reproduced.

Here, the optical disk 90 of the present embodiment is used for the high-density recording by the narrow track pitch of the information recording track formed by the mark row (or the emboss pit row) in the layer L, and is intended to increase the capacity.

An example of an information recording track is disclosed in FIGS. 2, 3, and 4.

Figure 2 illustrates an example of forming a track in a double spiral configuration. In addition, the "information recording track" is a track structure formed by a spiral continuous mark row (or a embossed pit row), and the term "track" means a track that is wound around one turn.

2A is a diagram showing an information recording track formed by layer L in a mark column (or embossed pit column: exemplified by an example of a mark column).

Further, Fig. 2B is a mode for revealing a track when the information track formed by the mark column is viewed in the plane direction of the disc.

As shown in FIG. 2B, the information recording track is formed into a spiral double spiral structure in which two independent tracks TKa and TKb are respectively formed.

Fig. 2A is an enlarged view of eight tracks (TK1 to TK8) adjacent to the radial direction of the information track of the double helix structure. Furthermore, in each of the tracks TK1 to TK8, (a) or (b) is added to the end of the symbol, and the tracks TK1, TK3, TK5, and TK7 of (a) are added as tracks on the track TKa, and are added. The tracks TK2, TK4, TK6, and TK8 of (b) are the tracks on the track TKb.

This information recording track system utilizes two adjacent tracks of the track on the track TKa and the track on the track TKb to form a track group. For example, the tracks TK1 and TK2 are track groups, and the tracks TK3 and TK4 are track groups.

Here, the orbit group refers to a combination of adjacent tracks adjacent to each other with a track pitch Tp1. Then, the track pitch Tp1 is a first track pitch which is shorter than the track pitch which is optically blocked according to the wavelength of the irradiated laser light and the NA of the illumination optical system.

For example, between the tracks TK1 and TK2, the track pitch Tp1 is shorter than the optical interception.

Further, the tracks adjacent to each other in the adjacent track group are separated by the track pitch Tp2. The track pitch Tp2 is, for example, a second track pitch which is longer than the track pitch corresponding to the optical block.

For example, between the tracks TK2 and TK3, between the tracks TK4 and TK5, and the like, the tracks are adjacent to each other in the adjacent track groups, and the equal intervals become the track pitch Tp2.

The track group pitch TpG indicates the pitch of the track groups. When the track pitch Tp2 is longer than the track pitch corresponding to the optical occlusion, the track group pitch TpG is necessarily longer than the track pitch corresponding to the optical occlusion.

That is, the information recording track of FIG. 2 forms a track group adjacent to the two tracks by using a track pitch Tp1 which is shorter than the track pitch corresponding to the optical interception, and the track group spacing TpG of the adjacent track groups. Ratio The track pitch equivalent to optical occlusion is also long.

Then, the information recording track system is as shown in FIG. 2B, and the two independent tracks TKa and TKb are respectively formed into a spiral double spiral structure, and the tracks TKa and TKb are formed to be shorter than the track pitch corresponding to the optical occlusion. Track group with track pitch Tp1. Further, the track group pitch TpG of the track group adjacent to each other in the double spiral structure is longer than the track pitch corresponding to the optical block.

The track pitches Tp1 and TpG are described in detail later. However, in the track adjacent to the track pitch Tp1 which is shorter than the optical blockage, the RF signal cannot be satisfactorily obtained as the reflected light information at the time of laser irradiation. , SUM signal, push-pull signal, etc.

In the present embodiment, the track group caused by the plurality of orbits adjacent to the track pitch Tp1 is configured to have a periodic structure of the track group pitch TpG which is longer than the optical block, and the tracking control signal can be extracted. .

Further, the track pitch Tp2 may be set to be shorter than the optical interception. That is, the track group pitch TpG may be longer than the pitch corresponding to the optical block.

For example, in the case of this double helix configuration, the track group spacing TpG = Tp1 + Tp2. Therefore, even if any of the track pitches Tp1 and Tp2 is shorter than the optical blocking, the Tp1+Tp2 ratio may be longer than the optical blocking. If the track pitch Tp2 is reduced to a length shorter than the optical interception, it is only advantageous in terms of high density. On the other hand, when the track pitch Tp2 is longer than the length corresponding to the optical breakage, the crosstalk at the time of extraction or reproduction of the tracking error signal TE or It is advantageous from the viewpoint of cross write at the time of recording.

The information recording track of the disk 90 of the embodiment may be a triple helix structure or a quadruple spiral structure in addition to the double spiral structure of FIG. 2, and may have a heavier spiral structure.

3A and 3B show the configuration of the information recording track in the same form as that of Figs. 2A and 2B.

As shown in FIG. 3B, the information recording track is formed into a spiral triple helix structure in which three independent tracks TKa, TKb, and TKc are respectively formed.

Fig. 3A is an enlarged view of nine tracks (TK1 to TK9) adjacent to the radial direction of the information track of the triple helix structure. Furthermore, the symbol tails (a), (b) and (c) of the respective tracks TK1 to TK9 reveal the tracks TKa, TKb, and TKc including the tracks.

This information recording track system uses the orbits on the track TKa, the tracks on the track TKb, and the three adjacent tracks of the track TKc to form a track group. For example, the tracks TK1, TK2, and TK3 are track groups, and the tracks TK4, TK5, and TK6 are track groups.

Then, the tracks in the track group are adjacent by the track pitch Tp1. Further, the adjacent track groups are separated from each other by the track group pitch TpG2.

That is, the information recording track of FIG. 3 forms a track group adjacent to three tracks by using a track pitch Tp1 which is shorter than the track pitch corresponding to the optical interception, and the track group spacing TpG of the adjacent track groups. The ratio is longer than the track pitch equivalent to optical occlusion.

Then, the information recording track system is as shown in FIG. 3B, and the independent three tracks TKa, TKb, and TKc are respectively formed into spiral triple spirals. The structure forms a track group of the track pitch Tp1 by the tracks TKa, TKb, and TKc. Further, the track group pitch TpG between the adjacent track groups in the triple helix structure is longer than the track pitch corresponding to the optical block.

In the case of this triple helix configuration, the orbital group spacing TpG = Tp1 + Tp2 + Tp1.

Therefore, if the track pitch Tp2 of the tracks adjacent to each other adjacent to each other (for example, the tracks TK3, TK4) is set to be longer than the track pitch corresponding to the optical occlusion, the track group pitch is inevitably TpG will be longer than the track pitch equivalent to optical occlusion.

Of course, the track pitch Tp2 may be shorter than the track pitch corresponding to the optical break.

4A and 4B show the configuration of the information recording track in the same form as that of Figs. 2A and 2B.

As shown in FIG. 4B, the information recording track is formed into a spiral quadruple spiral structure in which four independent tracks TKa, TKb, TKc, and TKd are respectively formed.

Fig. 4A is an enlarged view of 12 tracks (TK1 to TK12) adjacent to the radial direction of the information recording track of the quadruple spiral structure. Furthermore, the symbol tails (a), (b), (c), and (d) of the respective tracks TK1 to TK12 reveal the tracks TKa, TKb, TKc, and TKd including the tracks.

This information recording track system uses a track on the track TKa, a track on the track TKb, a track of the track TKc, and four adjacent tracks of the track TKd to form a track group. For example, the tracks TK1, TK2, TK3, and TK4 are track groups, and the tracks TK5, TK6, TK7, and TK8 are track groups.

Then, the tracks in the track group are adjacent by the track pitch Tp1. Further, the adjacent track groups are separated from each other by the track group pitch TpG.

That is, the information recording track of FIG. 4 forms a track group adjacent to four tracks by using a track pitch Tp1 which is shorter than the track pitch corresponding to the optical interception, and the track group spacing TpG of the adjacent track groups. The ratio is longer than the track pitch equivalent to optical occlusion.

Then, as shown in FIG. 4B, the independent four tracks TKa, TKb, TKc, and TKd are respectively formed into a spiral quadruple spiral structure, and the track pitches Tp1 are formed by the tracks TKa, TKb, TKc, and TKd. Track group. Further, the pitch of the adjacent track groups in the quadruple spiral structure is a track group pitch TpG which is longer than the track pitch corresponding to the optical block.

In the case of this quadruple spiral structure, the track group spacing TpG = Tp1 + Tp1 + Tp1 + Tp2.

Therefore, if the track pitch Tp2 of the tracks adjacent to each other adjacent to each other (for example, the tracks TK4, TK5) is set to be longer than the track pitch corresponding to the optical occlusion, the track group pitch is inevitably TpG will be longer than the track pitch equivalent to optical occlusion.

Of course, the track pitch Tp2 may be shorter than the track pitch corresponding to the optical break.

Although the examples of the double helix structure, the triple helix structure, and the quadruple helix structure have been described above, the multiple helix structure of the five-helix structure or more can also be considered.

<2. Configuration Example of Disc Drive Device>

The structure of the disc drive device (recording/reproducing device) of the present embodiment will be described with reference to Fig. 5 .

The disc drive device of the embodiment can be used as a reproduction-only disc and a recordable disc (a single readable and readable disc or a rewritable disc) as the disc 90 having the above-described embodiment of the information recording track structure. To carry out regeneration or recording.

When the optical disk 90 of the embodiment is mounted on the disk drive device, it is stowed on a turntable (not shown), and is rotationally driven by the spindle motor 2 at a constant linear velocity (CLV) or a constant angular velocity (CAV) during the recording/reproduction operation. .

Then, at the time of reproduction, the mark information (or embossed pit information) of the information track recorded on the optical disk 90 is read by the optical pickup (optical head) 1.

Further, in the case of data recording on the optical disk 90, the user data is recorded as a mark column by the optical pickup 1 on the track on the optical disk 90.

In the optical pickup 1, a laser diode serving as a laser light source, a photodetector for detecting reflected light, an object lens serving as an output end of the laser light, and a transmission lens are irradiated to the disc recording surface. The light is emitted, and the reflected light is guided to the optical system of the photodetector.

In the optical pickup 1, the object lens is held to be movable in the tracking direction and the focusing direction by a two-axis mechanism.

Further, the optical pickup 1 as a whole is movable in the radial direction of the disk by the screw mechanism 3.

Further, the laser diode system of the optical pickup 1 is driven by laser light by the laser driver 13 to perform laser light emission.

The reflected light information from the disc 90 is detected by the photodetector and supplied to the matrix circuit 4 in response to an electrical signal of the amount of received light.

The matrix circuit 4 includes a current-voltage conversion circuit and a matrix operation/amplification circuit corresponding to an output current from a plurality of light-receiving elements as photodetectors, and generates a desired signal by matrix calculation processing.

For example, a reproduction information signal (RF signal) equivalent to the reproduction data, a focus error signal for performing servo control, a tracking error signal, and the like are generated.

The reproduced information signal output from the matrix circuit 4 is supplied to the data detection processing unit 5 via the crosstalk cancel circuit 6. Further, the focus error signal and the tracking error signal outputted from the matrix circuit 4 are supplied to the optical block servo circuit 11.

The crosstalk cancellation circuit 6 performs crosstalk cancellation processing on the RF signal. The optical disk 90 of the present embodiment has a track adjacent to each other with a very narrow track pitch Tp1 as illustrated in FIGS. 2, 3, and 4. The narrower the track pitch, the more the mixing of the crosstalk components adjacent to the track becomes. Here, the crosstalk canceling circuit 6 is provided to perform processing for canceling the RF signal component of the adjacent track.

Further, depending on the format (track pitch, etc.) of the information recording track on the optical disk 90, the crosstalk canceling circuit 6 may not be provided.

Further, the crosstalk canceling circuit 6 controls the operation of the matrix circuit for the generation of the tracking error signal.

The data detection processing unit 5 performs binarization processing of the reproduced information signal.

For example, the data detection processing unit 5 performs A/D conversion processing of RF signals, reproduction clock generation processing by PLL, PR (Partial Response) processing, and Viterbi decoding (maximum likelihood decoding). A partial response maximum likelihood decoding process (PRML detection method: Partial Response Maximum Likelihood detection method) is performed to obtain a 2-value data column.

Then, the data detection processing unit 5 supplies the binary data sequence as the information read from the optical disk 90 to the encoding/decoding unit 7 in the subsequent stage.

The encoding/decoding unit 7 performs mediation of the reproduced data at the time of reproduction and modulation processing of the recorded data at the time of recording. That is, data reconciliation, deinterleaving, ECC decoding, address decoding, etc. are performed during reproduction, and ECC encoding, interleaving, data modulation, and the like are performed at the time of recording.

At the time of reproduction, the binary data sequence decoded by the above-described data detection processing unit 5 is supplied to the encoding/decoding unit 7. The encoding/decoding unit 7 performs a mediation process for the binary data sequence, and acquires the reproduced data from the optical disk 90.

For example, the data recorded on the optical disc 90 is a continuous length limit code modulation (RLL; Run Length Limited, PP: Parity preserve/Prohibit rmtr (repeated minimum transition run length) which is applied with RLL (1, 7) PP modulation or the like. At this time, the mediation process for such data modulation is performed, and the ECC decoding process is used to perform error correction to obtain the reproduced data from the optical disk 90.

The data decoded by the encoding/decoding unit 7 to the reproduced data is transmitted to the host interface 8, and transmitted to the host device 100 in accordance with an instruction from the system controller 10. The host device 100 is, for example, a computer device or an AV (Audio-Visual) system device.

At the time of recording, the recorded data is transferred from the host device 100, but the recorded data is supplied to the encoding/decoding portion 7 through the host interface 8.

At this time, the encoding/decoding unit 7 performs an encoding process of recording data, and adds an error correction code (ECC code), an interleave, a sub-code, and the like. Further, for the data to which the processing is applied, a continuous length limit code modulation such as the RLL (1-7) PP method or the like is applied.

The recording data processed by the encoding/decoding unit 7 is supplied to the writing strategy unit 14. In the write strategy unit, as the recording compensation process, the laser drive pulse waveform adjustment such as the characteristics of the recording layer, the spot shape of the laser light, and the recording linear velocity is performed. Then, the laser driving pulse is output to the laser driver 13.

The laser driver 13 performs laser light emission by the laser diode in the optical pickup 1 in accordance with the laser driving pulse for performing the recording compensation process. Thereby, a mark corresponding to the recorded material is formed on the optical disk 90.

Further, the laser driver 13 is equipped with a so-called APC circuit (Auto Power Control) to monitor the laser output power while monitoring the output of the laser detector provided in the optical pickup 1. The output of the laser is not controlled in a certain way due to changes in temperature and the like.

The target value of the laser output during recording and regeneration is from the system controller. The 10 is given so as to control each of the laser output levels to be the target value at the time of recording and reproduction.

The optical block servo circuit 11 generates various servo drive signals for focusing, tracking, and screwing based on the focus error signal and the tracking error signal from the matrix circuit 4, and performs servo operations.

That is, the focus drive signal and the tracking drive signal are generated in response to the focus error signal and the tracking error signal, and the focus coil and the tracking coil of the two-axis mechanism in the optical pickup 1 are driven by the two-axis driver 18. Thereby, the picker 1, the matrix circuit 4, the optical block servo circuit 11, the two-axis driver 18, the tracking servo loop caused by the two-axis mechanism, and the focus servo loop.

Further, the optical block servo circuit 11 performs the track jump operation by outputting the skip drive signal by turning off the tracking servo circuit in response to the track jump command from the system controller 10.

Moreover, the optical block servo circuit 11 generates a screw drive signal based on a screw error signal obtained from a low frequency band component of the tracking error signal, an access execution control from the system controller 10, and the like, and drives the screw by the screw driver 19. Agency 3. Though not shown, the screw mechanism 3 has a mechanism for holding the spindle shaft, the screw motor, the transmission gear, and the like of the pickup 1, and drives the screw motor in response to the screw drive signal to perform the required sliding of the optical pickup 1. mobile.

The spindle servo circuit 12 performs control for causing the spindle motor 2 to perform CLV rotation.

The spindle servo circuit 12 is obtained as a clock of the PLL processing for the RF signal, and the rotational speed of the motor 2 as the current spindle is obtained. Information, and compare it with the specified CLV (or CAV) reference speed information to generate a shaft error signal.

Then, the spindle servo circuit 12 outputs a spindle drive signal generated in response to the spindle error signal, and the spindle driver 17 performs CLV rotation or CAV rotation of the spindle motor 2.

Further, the spindle servo circuit 12 generates a spindle drive signal in response to the spindle start/brake signal from the system controller 10, and performs an operation of starting, stopping, accelerating, decelerating, and the like of the spindle motor 2.

Further, the spindle motor 2 is provided with, for example, an FG (Freqency Generator) and a PG (Pulse Generator), and the output thereof is supplied to the system controller 10. Thereby, the system controller 10 can recognize the rotation information (rotation speed, rotation angle position) of the spindle motor 2.

The various operations of the servo system and the recording and reproducing system as described above are controlled by the system controller 10 formed by the microcomputer.

The system controller 10 executes various processes in response to an instruction from the host device 100 given by the host interface 8.

For example, when a write command is issued from the host machine 100, the system controller 10 first moves the pickup 1 to the address of the logical or physical space to be written. Then, the encoding/decoding unit 7 performs encoding processing on the data (for example, video material or audio material, etc.) transmitted from the host device 100 as described above. Then, as described above, the laser driver 13 performs laser light emission driving based on the data to be encoded, and performs recording.

For another example, the host machine 100 supplies a certain one recorded on the optical disc 90. When the read command of the transfer of the data is made, the system controller 10 first performs the search operation control with the target address as the target. That is, an instruction is given to the optical block servo circuit 11 to perform an access operation of the optical pickup 1 targeting the address specified by the search command.

Thereafter, action control required to transfer the data of the instructed data section to the host device 100 is performed. That is, the data reading from the disc 90 is performed, and the data detection processing unit 5 and the encoding/decoding unit 7 are reproduced, and the requested data is transmitted.

Incidentally, the example of Fig. 1 has been described as a disk drive device connected to the host device 100. However, the disk drive device may be connected to another device. At this time, the operation unit and the display unit are provided, and the structure of the interface portion where the data is input and output is different from that of FIG. 1 . That is, recording and reproduction are performed in response to the user's operation, and a terminal portion for outputting various materials can be formed. Of course, as various structural examples of the disc drive device, other various examples are also conceivable.

<3. Record reproduction method>

Various examples of the recording and reproducing method as the embodiment will be described.

Fig. 6 is a view showing an example of a recording operation and a reproduction operation when the information recording track is set to the double spiral structure of Fig. 2; In each figure, the information track is revealed by a solid line or a dotted line.

6A is a view of irradiating the two reproducing laser spots SPp1 and SPp2 due to the laser of the reproducing power with the two recording laser spots SPr1 and SPr2 due to the laser of the recording power to the layer L of the optical disk 90. example.

In particular, an example of a double spiral track is formed at the same time.

The reproducing laser spots SPp1 and SPp2 are laser light for servo for detecting a tracking error signal. Then, the tracking control is performed such that the reproducing laser spots SPp1 and SPp2 track the track groups of the double spiral tracks TKx and TKx+1. For example, it is controlled by the track at the center of the tracks TKx and TKx+1.

Further, the track pitch Tp1 between the tracks TKx and TKx+1 is smaller than the track pitch which is shorter than the optical block, but is obtained as information of the reflected light by the two reproducing laser spots SPp1 and SPp2. The differential signal of each radial contrast signal can obtain a tracking error signal. This will be detailed later.

At this time, the optical pickup 1 irradiates the recording laser spots SPr1 and SPr2 in a state of being spaced apart from each other by the track pitch Tp1 in the radial direction of the disk. Further, the reproducing laser spot SPp2 and the recording laser spot SPr1 are irradiated in a state of being spaced apart from the track pitch Tp2 in the radial direction of the disk.

In this way, the tracking group (the tracks TKx and TKx+1) on the inner circumference side can be controlled by the tracking, and the outer peripheral side can be used by the recording laser spots SPr1 and SPr2 along the tracks TKx and TKx+1. The tracks TKx+2 and TKx+3 are recorded at the track group spacing TpG.

Further, by using a track in which a double helix is simultaneously formed, recording with a high transfer rate can be realized.

In addition, such a recording operation is performed by using a laser beam for reproduction on the inner circumference side while performing tracking control on the outer circumference side, and recording is performed on the outer circumference side by the recording laser spot. This type of tracking servo method is called It is "adjacent tracking servo".

When this adjacent tracking servo is performed, first, there must be a track of the first turn.

As shown in FIG. 1C, when the reference surface RL is provided, the concave track of the reference surface RL or the like can be used, and the double spiral track of the first turn can be formed by guiding the concave track of the reference surface RL or the like. After the second lap thereafter, as shown in FIG. 6A, the recording can be performed by the adjacent tracking servo.

On the other hand, as shown in FIG. 1A and FIG. 1B, when there is no reference plane RL, an operation example shown in FIGS. 9A to 9D can be considered.

First, as shown in FIG. 9A, the guide tracks TKG1 and TKG2 which are perfect circles of one week are recorded on the layer L of the optical disk 90. In the state where the optical pickup 1 fixes the position of the laser spot, it can be formed by rotating the optical disk 90 once. Specifically, the guide track TKG1 is first formed, and then the adjacent tracking servo is applied to the guide track TKG1 to form the guide track TKG2.

At this time, the interval (track pitch) between the guide tracks TKG1 and TKG2 of the concentric circles is set to be equal to the track group pitch TpG.

Thus, when the guide tracks TKG1, TKG2 are recorded, the track jump from the guide tracks TKG1 to TKG2 is learned to be a skip pulse that is rotated one revolution. That is, a skip pulse of the track revealed by the broken line in Fig. 9B is formed.

Then, using the learning skip pulse, as shown in Fig. 9C, the double spiral track of the first turn is recorded. By using the learning skip pulse, the first circle of the double spiral track TKa, TKb is gradually shifted toward the outer circumference side by the recording laser spot SPr1, SPr2 depending on the angular position. That is, the track of the first circle of the double spiral shape can be formed.

After the second lap, the adjacent tracking servo described in Fig. 6A can be utilized, and the double spiral track is recorded as shown by the broken line in Fig. 9D.

6B, the two reproducing laser spots SPp1 and SPp2 due to the laser of the reproducing power are irradiated to the layer L of the optical disk 90 by one recording laser spot SPr caused by the laser of the recording power. Examples of the respective tracks that form a double helix, respectively.

First, as in the case of a solid line, it is assumed that the orbit of the track TKa has been recorded in a spiral state. Further, at this time, the track of the track TKa is recorded such that the track pitch becomes Tp1 + Tp2.

In the state where the track of this track TKa exists, the track of the track TKb revealed by the broken line is recorded.

At this time, the reproducing laser spots SPp1 and SPp2 perform tracking control on the track of the track TKa of the solid line. For example, tracking control is performed such that the middle of the reproducing laser spots SPp1, SPp2 is located on the track of the track TKa.

Then, the recording laser spot SPr is irradiated in a state of being separated from the track TKa by the track pitch TKa in the radial direction of the disk.

In this way, the track in which the track TKa abuts to form the double spiral track TKb is recorded.

As a result, the data recording by the information recording track of Fig. 2 having the double spiral and having the track pitches Tp1, Tp2 and the track group pitch TpG can be performed.

Furthermore, as described above, this recording operation also performs the adjacent tracking servo, but at this time, the track is initially recorded before the double spiral track is formed. The orbit of the track TKa with a pitch of Tp1 + Tp2.

As shown in FIG. 1C, the reference plane RL is set, and when the concave track of the reference plane RL is used, the concave track of the reference plane RL or the like is used as a guide, and as shown in FIG. 9E, a double spiral of the track TKa of the track pitch Tp1+Tp2 is formed. The track is fine. Thereafter, the recording of the spiral track of the track TKb is performed as shown by the broken line in Fig. 9F by performing the adjacent tracking servo as shown in Fig. 6B.

On the other hand, as in the case of the reference plane RL as shown in FIGS. 1A and 1B, first, as shown in FIG. 9A, the guide tracks TKG1 and TKG2 which become perfect circles are recorded on the layer L of the optical disk 90.

Thus, when the guide tracks TKG1, TKG2 are recorded, as described with reference to FIG. 9B, the track jump from the guide tracks TKG1 to TKG2 is learned to be a skip pulse that is rotated one revolution. Then, using the learned skip pulse, the single-layer spiral track of the first turn of the track TKa is recorded.

Thereafter, after the second lap, the track having the track pitch Tp1 + Tp2 is formed by the adjacent tracking servo, and as shown in Fig. 9E, a spiral track as the track TKa can be formed.

Thereafter, the recording of the spiral track of the track TKb is performed as shown by the broken line in Fig. 9F by performing the adjacent tracking servo as shown in Fig. 6B.

Next, the reproduction operation will be described using FIG. 6C.

This is an example of the reproduction operation when the information recording track of the double spiral structure of FIG. 2 is formed by the recording operation (or the reproduction dedicated disk) of FIG. 6A or FIG. 6B.

At this time, the two reproducing laser spots SPp1 and SPp2 due to the laser of the reproducing power are irradiated to the layer L of the optical disk 90. Regeneration laser spot SPp1 SPp2 is irradiated in a state in which the track pitch Tp1 is spaced apart from each other in the radial direction of the disk.

Then, the reproducing laser spots SPp1 and SPp2 are respectively traversed on the tracks TKx and Tkx+1 of the track pitch Tp1.

Although the track pitch Tp1 is shorter than the track pitch corresponding to the optical break, the differential signal of each radial contrast signal obtained by the information of each of the two reflected laser spots SPp1 and SPp2 can be used. Get the tracking error signal. By using the tracking servo control of the tracking error signal, the reproducing laser spots SPp1 and SPp2 are placed on the tracks TKx and TKx+1 to be combined.

Then, the data of the tracks TKx and TKx+1 can be reproduced based on the reflected light information of the reproducing laser spots SPp1 and SPp2.

Further, by using the track in which the double helix is simultaneously reproduced, high-rate reproduction can be realized.

Next, in FIG. 7, a recording operation example and a reproduction operation example in the case where the information recording track is similarly set to the double spiral structure of FIG. 2 will be described. This example is an example of a laser spot for the servo laser spot SPp45, which is an astigmatic laser spot that is illuminated at an angle of 45° for the direction of the information recording track.

First, FIG. 7A shows an example in which the servo laser spot SPp45 due to the laser of the reproducing power and the two recording laser spots SPr1 and SPr2 due to the laser of the recording power are irradiated to the layer L of the optical disk 90. In particular, an example of a track that simultaneously forms a double helix is disclosed.

The tracking control is performed such that the servo laser spot SPp45 tracks the track group of the double spiral tracks TKx and TKx+1. For example The tracking is controlled at the center of the tracks TKx, TKx+1.

Further, although the track pitch Tp1 between the tracks TKx and TKx+1 is shorter than the track pitch corresponding to the optical break, the laser light is applied as the servo laser spot SPp45 to impart astigmatism. As a tangential push-pull signal of the reflected light information (for the direction of the track line, the differential signal of each photodetector divided in the vertical direction), a tracking error signal can be obtained. This will be detailed later.

At this time, the optical pickup 1 is irradiated in a state where the recording laser spots SPr1, SPr2 are spaced apart from each other by the track pitch Tp1 in the disk radial direction. Further, the servo laser spot SPp45 and the recording laser spot SPr1 are irradiated with a track pitch Tp2+ (Tp1/2) in the radial direction of the disk.

In this manner, the track TKx and TKx+1 can be tracked on the inner circumference side, and the track TKx+ can be recorded on the outer circumference side by the recording laser spots SPr1 and SPr2 along the tracks TKx and TKx+1. 2. TKx+3. As a result, an information recording track having a double spiral structure having track pitches Tp1, Tp2 and track group pitch TpG as shown in FIG. 2 is formed.

At this time, recording with a high transfer rate can be realized by using a track in which a double helix is simultaneously formed.

Further, when recording the track group of at least the first rotation of the adjacent tracking servo, the recording by the reference plane RL, the recording operation described with reference to FIGS. 9A to 9D, and the like may be performed.

Next, FIG. 7B is a laser light for laser beam SPp45 due to a laser of regenerative power, and one laser light for recording caused by a laser of recording power. The point SPr is irradiated to the layer L of the optical disk 90 to form an example of each track of the double spiral, respectively.

First, as in the case of a solid line, it is assumed that the orbit of the track TKa has been recorded in a spiral state. Further, at this time, the track of the track TKa is recorded such that the track pitch becomes Tp1 + Tp2 (= TpG).

In the state where the track of this track TKa exists, the track of the track TKb revealed by the broken line is recorded.

At this time, the tracking control is performed such that the servo laser spot SPp45 is aligned with the track of the track TKa of the solid line.

Then, the recording laser spot SPr is irradiated in a state of being separated from the track TKa by the track pitch TKa in the radial direction of the disk.

In this way, the track in which the track TKa abuts to form the double spiral track TKb is recorded.

As a result, the data recording by the information recording track of Fig. 2 having the double spiral and having the track pitches Tp1, Tp2 and the track group pitch TpG can be performed.

In addition, when the track of the track TKa of one of the spiral tracks is recorded, the recording by the reference plane RL, the recording operation described with reference to FIGS. 9A, 9B, 9E, and 9F may be performed.

Next, the reproduction operation will be described using FIG. 7C.

This is an example of the reproduction operation when the information recording track of the double spiral structure of FIG. 2 is formed by the recording operation (or the reproduction dedicated disk) of FIG. 7A or FIG. 7B.

At this time, the servo laser spot caused by the laser of the regenerative power The SPp 45 is irradiated to the layer L of the optical disk 90 with the two reproducing laser spots SPp1, SPp2.

In particular, the tracking control is performed such that the servo laser spot SPp45 tracks the track groups of the tracks TKx and TKx+1. For example, it is controlled by the track at the center of the tracks TKx and TKx+1.

For the reproducing laser spots SPp1 and SPp2, the track pitch Tp1 is separated in the radial direction, and the reproducing laser spot SPp1 and the servo laser spot SPp45 are arranged in the radial direction, and are separated by Tp2+ (Tp1/). 2) Irradiation in the same way.

In this state, the reproducing laser spot SPp1, SPp2 is aligned in the track TKx+2, TKx+3 by using the adjacent tracking servo which is the tangential push-pull signal of the reflected light information of the servo laser spot SPp45. on.

Thereby, the data of the tracks TKx+2 and TKx+3 can be reproduced based on the reflected light information of the reproducing laser spots SPp1 and SPp2.

Further, as shown in FIG. 7D, when the servo laser spot SPp45 tracks the centers of the tracks TKx and TKx+1, the reproducing laser spots SPp1 and SPp2 are respectively aligned on the tracks TKx and TKx+1, and may be reproduced according to the reproduction. The information of the orbits TKx and TKx+1 is reproduced by using the reflected light information of the laser spots SPp1 and SPp2.

In either of the cases of FIGS. 7C and 7D, the track of the double helix can be simultaneously reproduced, and the high transmission rate can be realized.

Next, a recording operation example and a reproduction operation example in the case where the information recording track is set to the triple helix structure of FIG. 3 will be described with reference to FIG.

Fig. 8A is three reproducing laser light caused by laser of regenerative power The points SPp1, SPp2, and SPp0 are irradiated to the layer L of the optical disk 90 by the three recording laser spots SPr1, SPr2, and SPr3 due to the laser of the recording power.

In particular, an example of a track of a triple helix is formed at the same time.

The reproducing laser spots SPp1, SPp0, and SPp2 are laser light for servo for detecting a tracking error signal. Then, the tracking control is performed such that the reproducing laser spots SPp1, SPp0, and SPp2 track the track groups of the triple spiral tracks TKx, TKx+1, and TKx+2.

Furthermore, the track pitch Tp1 between the tracks TKx, TKx+1, and TKx+2 is shorter than the track pitch which is shorter than the optical break, but as the laser spot for reproducing two of the three The tracking signals of the radial contrast signals obtained by the reflected light information of SPp1 and SPp2 can obtain the tracking error signal. This will be detailed later.

At this time, the optical pickup 1 irradiates the recording laser spots SPr1, SPr2, and SPr3 in a state of being spaced apart from each other by the track pitch Tp1 in the radial direction of the disk. Further, the reproducing laser spot SPp2 and the recording laser spot SPr1 are irradiated in a state of being spaced apart from the track pitch Tp2 in the radial direction of the disk.

In this way, the tracking group (tracks TKx, TKx+1, and TKx+2) on the inner circumference side can be tracked, and the recording laser spots SPr1, SPr2, and SPr3 are recorded along the track group. The outer circumference side tracks TKx+3, TKx+4, and TKx+5. In other words, a track group having a track group pitch TpG longer than the optical blockage can be formed while forming a track having a track pitch Tp1 shorter than the optical block.

Further, with the track in which the triple helix is simultaneously formed, recording with a high transfer rate can be realized.

Further, in the case of recording the track group of at least the first rotation required for performing the above-described adjacent tracking servo, the recording by the reference plane RL, the recording operation described with reference to FIGS. 9A to 9D, and the like may be performed.

Next, Fig. 8B is an example of forming the respective tracks TKa, TKb, and TKc of the triple helix, respectively.

First, the recording of the tracks TKa and TKb may be performed by the technique shown in Fig. 6B. However, when recording the track TKa, the track pitch is Tp1 + Tp1 + Tp2 (= TPG).

In Fig. 8B, the state of the track (dashed line) of the track TKc is recorded as the third spiral track after forming the tracks of the tracks TKa, TKb as in the solid line.

The optical pickup 1 irradiates the two reproducing laser spots SPp1 and SPp2 due to the laser of the reproducing power and the one recording laser spot SPr due to the laser of the recording power to the layer L of the optical disk 90. example.

At this time, the reproducing laser spots SPp1 and SPp2 perform tracking control on the two tracks of the tracks TKa and TKb of the solid line. However, at least the reproducing laser spot SPp2 may be controlled by the track of the track TKb.

For example, if the reproducing laser spots SPp1 and SPp2 are separated by the track pitch Tp1 in the radial direction, the tracking control may be performed such that the center of the reproducing laser spots SPp1 and SPp2 is located between the tracks TKa and TKb.

Then, the laser spot SPr is recorded to recover from the laser spot for regeneration. SPp2 is irradiated in a state in which the track pitch Tp1 is separated in the radial direction of the disk.

In this way, the track of the track TKc in which the third heavy spiral is formed adjacent to the tracks TKa and TKb is recorded.

As a result, it is possible to perform data recording by the information recording track of Fig. 3 having a triple helix and having track pitches Tp1, Tp2 and track group pitch TpG.

Next, the reproduction operation will be described using FIG. 8C.

This is an example of the reproduction operation when the information recording track of the triple helix structure of FIG. 3 is formed by the recording operation (or the reproduction dedicated disk) of FIG. 8A or FIG. 8B. At this time, the three reproducing laser spots SPp1, SPp0, and SPp2 due to the laser of the reproducing power are irradiated to the layer L of the optical disk 90.

Then, the reproducing laser spots SPp1, SPp0, and SPp2 are irradiated in a state of being spaced apart from each other by the track pitch Tp1 in the radial direction of the disk. Then, the reproducing laser spots SPp1, SPp0, and SPp2 are traversed on the tracks TKx, TKx+1, and TKx+2 of the track pitch Tp1, respectively.

Although the track pitch Tp1 is a track pitch shorter than the optical break, the difference between the radial contrast signals obtained by the reflected light information of the two of the three reproducing laser spots SPp1 and SPp2 is obtained. Signal, you can get the tracking error signal. By using the tracking servo control of the tracking error signal, the reproducing laser spots SPp1, SPp0, and SPp2 are placed on the tracks TKx, TKx+1, and TKx+2, respectively.

Then, the data of the tracks TKx, TKx+1, and TKx+2 can be reproduced based on the reflected light information of the reproducing laser spots SPp1, SPp0, and SPp2.

Further, by using the track in which the triple helix is simultaneously regenerated, high transmission rate can be achieved.

The recording operation illustrated in FIGS. 6A, 6B, 7A, 7B, 8A, and 8B is such that a track group adjacent to a plurality of tracks is formed by the track pitch Tp1, and the adjacent track groups are at a track group pitch TpG. Separately, tracking control of the laser light for recording is performed, and a recording method of the information recording track is formed on the recording medium.

In particular, by recording the laser light, an information recording track in which a plurality of independent orbits are formed into a spiral multi-spiral structure is formed, and a track group of the track pitch Tp1 is formed by the plurality of tracks. Then, the track groups adjacent to each other in the multi-spiral structure are track-controlled so as to be the track group pitch TpG so as to perform the tracking laser spot.

As a result, it is possible to realize the optical disk 90 having the track pitch Tp1 (Tp1 and Tp2 depending on the condition) corresponding to the optical occlusion, and as a whole, high-density recording due to the narrow track pitch can be realized.

Further, in the reproducing operation illustrated in FIGS. 6C and 8C, at least two reproducing laser spots are irradiated to the complex orbits in the track group, and the reflected light information of the two reproducing laser spots is obtained. The differential signal of each radial contrast signal is set as a tracking error signal. Then, by using the tracking servo control of the tracking error signal, at least one or more reproducing laser spot is placed on any of the information tracks to perform the tracking control, and the reproduction of the reproduced data is performed based on the reflected light information. method.

Thereby, data reproduction can be realized based on the optical disk 90 having the track pitch Tp1 (Tp1 and Tp2 depending on the condition) corresponding to the optical interception. .

Further, in the regenerative operation illustrated in FIG. 7C and FIG. 7D, the servo laser spot SPp45 which is provided with the astigmatism at an angle of 45° is applied to the wiring direction of the information recording track, and the reproduction laser spot SPp45 for one or more is used. Laser spot. Then, the tangential push-pull signal obtained by the reflected light information of the servo laser spot SPp45 is used as a tracking error signal, and at least one or more reproductions are performed by the tracking servo control using the tracking error signal. The laser spot performs the tracking control to cause it to fall on any information track, and the method of reproducing the data is reproduced based on the information of the reflected light.

Thereby, data reproduction can be realized based on the optical disk 90 having the track pitch Tp1 corresponding to the optical cutoff (Tp1 and Tp2 depending on the situation).

<4. High density due to narrow track pitch>

As can be understood from the above description, in the present embodiment, high-density recording is realized as the optical disk 90 having the track pitch Tp1 or the like corresponding to the optical cutoff. Further, data reproduction can be realized based on the optical disk 90, and it can be appropriately established as a recording and reproducing system.

Here, the reason for forming the information recording track of FIGS. 2 to 4 will be described.

First, Figure 10 reveals the signal waveforms seen in previous Blu-ray disc systems. In the case of the Blu-ray disc system, recording and reproduction were carried out under the conditions of a combination of a laser having a wavelength of 405 nm (so-called blue laser) and an object lens having an NA of 0.85, and the track pitch was 0.32 μm.

Further, a spiral concave rail is formed on the recording surface, and the concave rail is a recording rail.

Fig. 10A is a view showing an RF signal observed in a so-called traverse state (a state in which a laser spot is traversed in a radial direction) and a push-pull signal P/P (a photodetector split along the direction of the track line) The differential radial push-pull signal).

Moreover, FIG. 10B is a SUM signal, which discloses an enlarged view of the low-band component signal of the RF signal and the push-pull signal P/P. The horizontal axis is set to detrack and is disclosed in the range of 0° to 360°. 360° is equivalent to the track pitch (= cycle).

The RF signal, the SUM signal, and the push-pull signal P/P all observe the signal modulation of the concave/bull track in response to the traverse. It can also be seen that the position information (tracking error signal) of the radial direction of the laser spot can be detected according to the push-pull signal P/P.

Here, it is considered to perform narrow track pitching for high-density recording.

Fig. 11 is a view showing the SUM signal and the push-pull signal P/P observed when the track pitch Tp is set from 0.32 μm to 0.27 μm and 0.23 μm.

Further, as the horizontal axis of the horizontal axis, "G" is the center position of the concave track, and "L" is the center position of the convex track.

As can be seen from Fig. 11, when the track pitch is gradually reduced, the modulation component of the SUM signal and the push-pull signal P/P is gradually reduced, and when it is 0.23 μm, no modulation component is observed.

The orbital pitch of 0.23 μm is almost the same as the optical interception in the case of a laser having a wavelength of 405 nm and an optical system having an NA of 0.85.

The optical occlusion will be described with reference to FIG.

The zero-order light and the diffracted light of the laser light (+1 time light, -1 order light) are shown in FIG. The amount of shift of the diffracted light is revealed by an arrow SF in the figure.

The amount of shift of the diffracted light when the radius of the circle is "1" is expressed by the following calculation formula.

The amount of displacement of the diffracted light = λ / (NA.p) = (λ / NA) / p

However, λ is the wavelength and p is the period of the periodic structure. The periodic structure is a period of a configuration such as a convex rail/a concave rail.

Regarding the laser light (reflected light) incident on the photodetector, the overlapping portion of the 0th order light and the ±1st order light is a modulation component.

That is, as the area of the overlapping portion revealed by the oblique line portion is larger, the difference in brightness between the detection of the photodetector is larger, and a larger signal modulation can be obtained.

When the circle of the radius "1" is set to "2" when the amount of shift of the diffracted light is "2", the overlapping portion disappears and the modulation component cannot be obtained.

That is, if (λ/NA)/p=2, the modulation signal cannot be obtained.

At the wavelengths λ and NA of the Blu-ray disc system, the period p of the period structure in which the shift amount is "2" is 0.24 μm.

Therefore, as the track pitch corresponding to the period p of the periodic structure, 0.24 μm is a pitch corresponding to optical blocking.

Organize into the following.

. When the period is p≦λ/(2NA), the modulation signal cannot be obtained.

. When the period p>λ/(2NA), the modulation signal can be obtained.

According to this, when considering the high-density recording caused by the narrow track pitch, It is impossible to carry out a narrow track pitch which is equivalent to optical interception.

Therefore, considering the same wavelength and NA as the Blu-ray disc system, the limit of the track pitch is 0.25 μm, and practically, the modulation component is hardly obtained in 0.25 μm, so that the actual track pitch is 0.27 μm or more.

Further, in the case of the Blu-ray disc system, although the concave rail/bump rail structure is provided, the optical disc 90 of the present embodiment does not have a concave rail/bulb rail structure in the layer L.

Since the concave rail/bulb rail structure is not formed in each layer L, it is advantageous for multilayering.

In such a situation, a large high-density recording due to the narrow track pitch is reviewed.

When the concave rail/bump configuration is not formed, the track itself as a mark column or a embossed pit train is a periodic structure that affects the signal modulation in the radial direction.

Therefore, when the information recording track is formed only by the track pitch Tp1 corresponding to the above-described optical blocking, the modulation component cannot be obtained, and the tracking servo cannot be applied.

However, for obtaining the modulation component for the signal as the reflected light information, it is found that even if the track pitch Tp1 below the optical interception corresponding to the period p ≦ λ / (2NA) is included, the period is p > λ / The method of (2NA) can constitute a track group. In other words, as the periodic structure due to the track group, the track group may be formed by a track group pitch TpG larger than the optical block.

That is, the capital constituting the structure illustrated in FIGS. 2, 3, and 4 is utilized. The recording track can obtain a modulation component as the reflected light information even if it includes the track pitch Tp1 corresponding to the optical blocking.

In Fig. 13, in the case where the wavelength λ = 405 nm and NA = 0.85, the SUM signal and the push-pull signal P/P of various track pitch structures are disclosed in the case where the layer L is not provided with the concave track/bump structure.

First, as described above, similarly to the conventional Blu-ray disc system, when the track pitch Tp is 0.32 μm, the modulation of the SUM signal is observed.

Then, when the track pitch is directly shortened and the track pitch Tp = 0.23 μm corresponding to the optical cutoff is not obtained, no modulation component is observed.

Here, it is assumed that the track structure has the track pitches Tp1 and Tp2 as shown in FIG. 2 . Here, it is assumed that Tp1=0.20 μm and Tp2=0.30 μm. Thus, as a SUM signal, a modulation component was observed. That is, the modulation component corresponding to the amount of the scattered rail can be obtained. At this time, the track group pitch TpG = 0.50 μm.

Further, in the signal waveform diagram in the case of Tp1=0.20 μm and Tp2=0.30 μm, the 360° of the horizontal axis of the horizontal axis is the track group period (corresponding to the track group pitch TpG). In the case of Tp=0.32 μm and Tp=0.23 μm (further in the cases of FIGS. 10 and 11), it is noted that the 360° of the horizontal axis is different from the state of the orbital period.

That is, in the case of Tp1 = 0.20 μm and Tp2 = 0.30 μm, the SUM signal indicates that one cycle of the modulation component can be obtained in the periodic unit of the track group.

Even in the subsequent planes, the sign of the loose track with the orbital group structure is 360°, which means the track group period.

Moreover, when the layer L is a mirror structure having no concave rail/bump rail structure, the recording is performed. If the mark has no phase difference, the push-pull signal P/P cannot be obtained.

In the case of Tp1=0.20 μm and Tp2=0.30 μm, since the modulation of the sufficient SUM signal can be obtained, the narrow track pitch is further reviewed as FIG.

In Fig. 14, the case where Tp1 = 0.19 μm and Tp2 = 0.27 μm is additionally disclosed, but in this case, sufficient SUM signal modulation can be obtained. At this time, the track group pitch TpG is 0.46 μm, and the average value of the track pitch is 0.23 μm, that is, it means that even if it is equal to the track pitch of the modulation component not observed in FIG. 13, it can be sufficiently obtained. Modulation.

As described above, with the structure of the information recording track of the embodiment, even if there is a track pitch Tp1 corresponding to the optical cutoff, it is confirmed that a periodic structure that does not reach optical breakage is available, that is, it has a track group. The track group of the pitch TpG acquires a modulation component corresponding to the signal of the radial direction (tracking control method).

<5. Tracking method>

As described above, the modulation component can be obtained as the SUM signal, and the optical disk 90 of the present embodiment can be subjected to the following method of tracking as illustrated in FIGS. 15 to 21 .

Fig. 15 is a flowchart showing an operation method of a tracking error signal applicable to the recording operation of Fig. 6A or Fig. 8B and the reproducing operation of Fig. 6C.

Fig. 15A is a view showing an information recording track of a double helix configuration.

The reproducing laser spots SPp1 and SPp2 are laser light for servo for detecting a tracking error signal. Then, using this laser spot for regeneration SPp1 and SPp2 perform tracking control on the track group of the double spiral track TKx and TKx+1.

For example, the center of the tracks TKx and TKx+1 is set to a position where the amount of the track is 270°. (360° is the period of the orbit group: the same applies to the following in Fig. 16 to Fig. 22)

The reflected light amount signals of the reproducing laser spots SPp1 and SPp2 are set to S1 and S2. At this time, as shown in FIG. 15B, the operation of the reflected light amount signal S2-S1 can be performed by the differential operation circuit 31 to generate the tracking error signal TE.

As the reflected light amount signals S1 and S2, as shown in Fig. 15C, a modulation component as a radial contrast signal can be obtained.

For example, if the reproducing laser spot SPp1 and SPp2 are shifted to the right in FIG. 15A, the reflected light amount signal S1 will be darkened (the signal level is lowered), and the reflected light amount signal S2 will be brightened (the signal level is increased).

Further, a condition of Tp1 = 0.19 μm and Tp2 = 0.27 μm (TpG = 0.46) is disclosed herein. Further, the SUM signal at this time is a signal in consideration of the virtual spot at the center position in the radial direction of the disk of the reproducing laser spot SPp1, SPp2.

Then, as the difference S2-S1 of the radial contrast component, the tracking error signal TE corresponding to the amount of the scattered track in the unit of the track group can be obtained.

According to the tracking error signal TE, the servo control is performed at the 270° position, and the tracking control by the reproducing laser spots SPp1 and SPp2 of Fig. 15A can be performed. Thereby, the recording operation of FIG. 6A or FIG. 8B and the reproducing operation of FIG. 6C can be performed.

However, in Fig. 15B, the reflected light amount signals S1, S2 are input to the crosstalk canceling circuit 6, and the operation of the differential arithmetic circuit 31 is adjusted by the equalization control signal TK-BL from the crosstalk canceling circuit 6.

When the difference between the reflected light amount signals S1 and S2 is simply obtained, the state of the track is lost due to the recording state of each track. Since the crosstalk canceling circuit 6 detects the crosstalk component of the adjacent track, the deviation of the light amount balance of the tracks TKx and TKx+1 can be corrected. Here, the crosstalk canceling circuit 6 outputs the equalization control signal TK-BL in such a manner that the crosstalk components of the adjacent tracks are equalized with each other.

In the differential operation circuit 31, in response to the equalization control signal TK-BL, an equalization adjustment operation for applying a correction coefficient corresponding to the recording state of each track is performed on each of the reflected light amount signals S1 and S2, and an operation of S2-S1 is performed. A suitable compensation bias voltage is applied to the result of the calculation, whereby a tracking error signal TE which is hardly affected by the recording state is generated.

In FIG. 15, although the illustration is omitted, the reflected light amount signals S1 and S2 applied with the crosstalk canceling circuit 6 by the crosstalk canceling circuit 6 are supplied to the data detecting processing unit 5 shown in FIG. 5.

That is, when the reproduction of FIG. 6C is performed, the reflected light amount signals S1 and S2 are used as RF signals for the tracks TKx and TKx+1 for data reproduction.

Next, Fig. 16 is a flowchart showing an operation method of a tracking error signal applicable to the recording operation of Fig. 6B.

As shown in Fig. 16A, the reproducing laser spots SPp1 and SPp2 are laser light for detecting the tracking error signal, and the reproducing laser spots SPp1 and SPp2 are used to sandwich one of the double spiral tracks. TKx While tracking the way to record the tracking control.

In this state, the adjacent tracking servo is performed, and the adjacent track TKx+1 is recorded by the recording laser spot SPr.

At this time, as shown in FIG. 16B, the tracking error signal TE can be obtained by an operation of the reflected light amount signal S2-S1 of the differential operation circuit 31. At this time, the adjustment of the reflected light amount signals S1 and S2 can be performed by the equalization control signal TK-BL from the crosstalk canceling circuit 6.

Further, since the track pitch is wide during recording, the RF output from the reproducing laser spots SPp1 and SPp2 is mostly from the track TKx, and the RF output and output signals from the reproducing laser spots SPp1 and SPp2 are used. Comparing the results, the signal regeneration and equalization control signal TK-BL of the track TKx can be obtained.

Various signal waveforms are disclosed in Figure 16C. Furthermore, since the track of the recording track TKa and the state of the recording track TKb are revealed later, the track pitch before recording is Tp1 + Tp2 = 0.46 μm.

As the reflected light amount signals S1, S2, and SUM signals, as shown, a radial contrast modulation component can be obtained. Then, as S2-S1, a tracking error signal TE corresponding to the amount of the scattered rail is obtained.

At this time, according to the tracking error signal TE, the servo control is at the 0° position, and the tracking control by the reproducing laser spots SPp1 and SPp2 of FIG. 16A can be performed. Thereby, the recording operation of FIG. 6B can be performed.

Next, Fig. 17 discloses an operation method of a tracking error signal applicable to the recording operation of Fig. 7A and the reproducing operation of Fig. 7C or Fig. 7D.

As shown in Fig. 17A, the wiring direction for the information track will be given The servo laser spot SPp45 of the astigmatism at an angle of 45° is irradiated to the layer L of the optical disk 90. Then, tracking control is performed such that the servo laser spot SPp45 tracks the track groups of the tracks TKx and TKx+1.

At this time, in the optical pickup 1, the reflected light of the servo laser spot SPp45 is received by the four-divided photodetector 33 shown in FIG. 17B. The signals obtained on the light receiving surfaces A, B, C, and D are supplied to the arithmetic circuit 34.

In the arithmetic circuit 34, the signal of the light receiving surface B+C is subtracted from the signal of the light receiving surface A+D, and this is output as the tracking error signal TE. That is, for the track line direction, the tangent push-pull signal of the differential signal of each photodetector divided in the vertical direction becomes the tracking error signal TE.

The signal waveform is shown in Figure 17C. Here, a condition of Tp1=0.20 μm, Tp2=0.30 μm, and TpG=0.50 μm is disclosed herein.

Further, the amount of astigmatism is a condition of Z6=0.275. (Z6 is the Z6 of the aberration polynomial of Fringe-Zamike)

As shown in the figure, as a tracking error signal TE caused by the tangential push-pull signal, a signal corresponding to the amount of the scattered rail is obtained.

According to the tracking error signal TE, the servo is controlled at the 270° position, and the tracking control of the track group can be performed by the servo laser spot SPp45 as shown in FIG. 17A. Thereby, the recording operation of FIG. 7A and the reproducing operation of FIG. 7C can be performed.

Next, Fig. 18 is a flowchart showing an operation method applicable to the tracking error signal of the recording operation of Fig. 7B.

As shown in FIG. 18A, the servo laser spot SPp45 is irradiated onto the disc. The layer L of 90 is such that it tracks the track TKx that has been formed in the double helix.

In this state, the adjacent tracking servo is performed, and the adjacent track TKx+1 is recorded by the recording laser spot SPr.

At this time, as shown in FIG. 18B, the tangent push-pull signal obtained by the operation of the (A+D)-(B+C) by the arithmetic circuit 34 becomes the tracking error signal TE. The signal waveform is shown in Fig. 18C. Further, since the track of the recording track TKa and the state of the track of the recording track TKb are revealed later, the track pitch before recording is Tp1 + Tp2 = 0.46 μm. Further, the amount of astigmatism is a condition of Z6=0.262.

As shown in the figure, as a tracking error signal TE caused by the tangential push-pull signal, a signal corresponding to the amount of the scattered rail is obtained.

According to the tracking error signal TE, the servo is controlled at the 0° position, and the tracking control of the servo laser spot SPp45 tracking track TKx can be performed as shown in FIG. 18A. Thereby, the recording operation of FIG. 7B can be performed.

Next, Fig. 19 discloses an operation method applicable to the tracking error signal of the recording operation of Fig. 8A and the reproduction operation of Fig. 8C.

Fig. 19A is a view showing an information recording track of a triple helix configuration.

The reproducing laser spots SPp1, SPp0, and SPp2 are laser light for servo for detecting a tracking error signal. Then, the reproduction laser spots SPp1, SPp0, and SPp2 perform tracking control so as to track the track groups of the triple spiral tracks TKx, TKx+1, and TKx+2.

The center of the tracks TKx, TKx+1, and TKx+2 is set to a position where the track is = 270°.

The amount of reflected light of the reproducing laser spots SPp1, SPp0, and SPp2 The signal is set to S1, S0, S2. At this time, as shown in FIG. 19B, the operation of the reflected light amount signal S2-S1 can be performed by the differential operation circuit 31 to generate the tracking error signal TE.

As the reflected light amount signals S1, S0, and S2, as shown in Fig. 19C, a modulation component as a radial contrast signal can be obtained. Further, a case of Tp1 = 0.19 μm and Tp2 = 0.26 μm is disclosed herein.

Then, as the difference S2-S1 of the radial contrast component, the tracking error signal TE corresponding to the amount of the scattered rail can be obtained.

According to the tracking error signal TE, the servo control is performed at the 270° position, and the tracking control by the reproducing laser spots SPp1 and SPp2 of Fig. 19A can be performed. Thereby, the recording operation of FIG. 8A and the reproducing operation of FIG. 8C can be performed.

Further, in Fig. 19B, the reflected light amount signals S1, S0, and S2 are input to the crosstalk canceling circuit 6, and the operation of the differential arithmetic circuit 31 is adjusted by the equalization control signal TK-BL from the crosstalk canceling circuit 6.

As described in the foregoing situation of FIG. 15, the differential operation circuit 31 first performs an equalization adjustment operation of applying a correction coefficient corresponding to the recording state of each track in each of the reflected light amount signals S1 and S2 in response to the equalization control signal TK-BL. The calculation of S2-S1 is performed, and the appropriate compensation bias is applied to the result of the calculation, whereby the tracking error signal TE which is hard to be affected by the recording state can be generated.

Further, although not shown in FIG. 19, the reflected light amount signals S1, S0, and S2 to which the crosstalk canceling circuit 6 applies the crosstalk canceling processing are supplied to the material detecting processing unit 5 shown in FIG. 5.

That is, when the reproduction of FIG. 8C is performed, the reflected light amount signals S1, S0, and S2 are used as RF signals for the tracks TKx, TKx+1, and TKx+2 for data reproduction.

Next, FIG. 20 is an example in which tracking is performed using the servo laser spot SPp45 for imparting astigmatism when the third track TKc is recorded in a state where the tracks TKa and TKb have been formed, as in FIG. 8B.

The recording operation of FIG. 8B may be performed by using two reproducing laser spots SPp1 and SPp2 as described above with reference to FIG. 15, but here, it is disclosed that one servo laser spot SPp45 is used. Sample.

As shown in FIG. 20A, the tracking control is performed such that the servo laser spot SPp45 tracks the tracks TKx and TKx+1 of the already formed tracks TKa and TKb.

At this time, as shown in FIG. 20B, the tangential push-pull signal can be obtained by the arithmetic circuit 34 and set as the tracking error signal TE.

As shown in Fig. 20C, as the tracking error signal TE, a signal corresponding to the amount of the scattered rail is obtained.

According to this tracking error signal TE, servo control is performed at a 90° position, and tracking control of the servo laser spot SPp45 tracking tracks TKx and TKx+1 can be performed as shown in FIG. 20A. The track of the third track TKc can be recorded by the adjacent tracking servo in this state to record the laser spot SPr.

Fig. 21 is a view showing the same servo system as that of the tracking servo system of Fig. 19. However, in the information track of the triple helix, the tracks of the tracks TKa and TKc have been formed, and the track TKb of the center has not been recorded. Tracking servo mode.

As shown in Fig. 21A, since the track of the track TKb in the middle is unrecorded, the distance between the track of the track TKa and the track of the track TKc is Tp1 + Tp1 = 0.38. Also, the track pitch between the track groups is Tp2 = 0.26.

The generation mode g of the tracking error signal TE of Fig. 21B is the same as that of Fig. 19B.

The waveform of each signal is shown in Fig. 21C. At this time, since there is no center spiral, although the polarity of the tracking error signal TE is opposite to that of FIG. 19, for example, the tracking servo of FIG. 21A can be performed by servo control at the 270° position.

Thus, even in the state where the spiral track in the middle of the triple helix is unrecorded, servo control can be performed for recording or reproduction.

However, it has been previously described that not only the track pitch Tp1 but also the track pitch Tp2 is equivalent to the track pitch below the optical cutoff.

In the example of FIGS. 15 to 21 described above, an example in which the track pitch Tp2 is longer than the optical breakage is disclosed. In this case, the track group pitch TpG is necessarily longer than the optical break.

In FIG. 22, it is disclosed that the tracking error signal TE can be obtained even if the track pitches Tp1 and Tp2 are equal to or less than the optical blocking length, as long as the track group pitch TpG is longer than the optical blocking.

22A, 22B, and 22C are the same as FIG. 15, and the state of the tracking error signal TE is obtained by the radial contrast signals of the reproducing laser spots SPp1 and SPp2 for the information track of the double spiral structure.

At this time, it is assumed that the track pitch Tp1=0.15 μm, Tp2=0.23 μm, both It is equivalent to optically intercepting the following track pitch. The track group spacing TpG is 0.38 μm.

As the reflected light amount signals S1 and S2, as shown in Fig. 22C, a modulation component as a radial contrast signal can be obtained.

Then, as the difference S2-S1 of the radial contrast component, the tracking error signal TE corresponding to the amount of the scattered rail can be obtained.

According to the tracking error signal TE, the servo control is performed at the 270° position, and the tracking control by the reproducing laser spots SPp1 and SPp2 of Fig. 22A can be performed.

As described above, even if the track pitches Tp1 and Tp2 correspond to the track pitch below the optical cutoff, an appropriate tracking servo can be performed as long as the track group pitch TpG is longer than the optical break.

In addition, in FIG. 22, the tracking method of FIG. 15 is used as a guide. However, even in the case of the tracking method described in FIGS. 16 to 21, even if the track pitches Tp1 and Tp2 correspond to optical masking, The track pitch below is broken, and an appropriate tracking servo can be performed as long as the track group pitch TpG is longer than the optical break.

<6. Optical system structure example>

An example of the structure of the optical system of the optical pickup 1 for realizing the recording operation and the reproducing operation of the above embodiment will be described.

Fig. 23 is an example of a case where a plurality of laser spots are used for a tracking servo, as in Figs. 6 and 8, for example.

As the optical system in the optical pickup 1, a multi-beam LD is provided ( The laser diode 41, the collimator lens 42, the spectroscope 43, the objective lens 44, the multiple lens 45, the light receiving element portion 46, and the two-axis mechanism 47.

The laser light emitted from the multi-beam LD 41 is parallel light by the collimator lens 42 and is collected by the spectroscope 43 by the object lens 44 to be irradiated onto the optical disk 90.

The objective lens 44 can be held in the focus direction and the tracking direction by the two-axis mechanism 47. The two-axis mechanism 47 is driven by the two-axis actuator 18 shown in Fig. 5 to perform tracking servo and focus servo.

The reflected light from the optical disk 90 is reflected by the spectroscope 43 through the objective lens 44, and reaches the multiple lens 45. Then, it is condensed by the multiple lens 45 and incident on the light receiving element portion 46.

In this configuration, as the multi-beam LD41, the structures of the light-emitting surfaces of the example 1 to the example 4 are considered in the drawing, and the light detector structure of the light-receiving element portion 46 is considered as an example of the multi-beam LD41. ~ Example 4.

In the first embodiment, the multi-beam LD 41 has a structure in which a light-emitting surface of a double beam for reproduction is used, and the light-receiving element portion 46 has a structure in which two four-divided photodetectors PD1 and PD2 are provided. This is a reproduction device, and for example, a configuration example in the case of the reproduction operation described with reference to FIGS. 6C and 15 can be performed.

The two reproducing laser spots SPp1, SPp2 are irradiated, and the reflected lights are detected by the photodetectors PD1, PD2. The sum signal of the four divided light receiving surfaces of the photodetectors PD1 and PD2 is the reflected light amount signals S1 and S2 in FIG.

And by the operation of each signal of the four-divided light-receiving surface, a focus error is generated. Other necessary signals such as the false alarm number.

In the example 2, the multi-beam LD 41 has a structure in which a light-emitting surface of three beams for exclusive use is used, and the light-receiving element portion 46 has a structure in which two photodetectors PD3 and PD5 and a four-divided photodetector PD4 are provided.

This is a reproduction device, and for example, a configuration example in the case of the reproduction operation described with reference to FIGS. 8C and 19 can be performed.

The three reproducing laser spots SPp1, SPp0, and SPp2 are irradiated, and the reflected lights are detected by the photodetectors PD3, PD4, and PD5. The reflected light amount signals S1 and S2 in Fig. 19 are obtained from the photodetectors PD3 and PD5. Further, the sum signal of the four divided light receiving surfaces of the photodetector PD4 is the reflected light amount signal S0.

Further, by the calculation of the signals of the four divided light receiving surfaces of the photodetector PD4, other necessary signals such as focus error signals are generated.

In the example 3, the structure of the recording operation of FIG. 6(a) is performed, and the multi-beam LD41 has a structure in which the light-emitting surface of the two beams for reproduction and the light-emitting surface of the two beams for recording are used. Accordingly, the light-receiving element portion 46 is used for the reproducing laser spots SPp1 and SPp2, and two photodetectors PD6 and PD7 are provided, and the recording laser spots SPr1 and SPr2 are provided with two photodetectors PD8 and PD9.

In the example 4, the structure of the recording operation of FIG. 8(a) is performed, and the multi-beam LD41 has a structure in which the light-emitting surface of the three beams for reproduction and the light-emitting surface of the three beams for recording are provided. In response to this, the light receiving element unit 46 is used for the reproducing laser spots SPp1, SPp2, and SPp3, and is provided with three photodetectors PD10, PD11, and PD12, and the recording laser spots SPr1, SPr2, and SPr3 are provided. There are three photodetectors PD13, PD14, and PD15.

Fig. 24 is a view showing an example 2 of the present invention, that is, a configuration having a reproduction-only three-beam light-emitting surface and a light-receiving element portion 46 (photodetectors PD3, PD4, PD5) as an example, and revealing that three optical laser spots are formed on the optical disk 90. Multi-beam person.

As shown, the three laser beams from the multi-beam LD 41 are optically induced by the collimating lens 42, the spectroscope 43, and the object lens 44, and three light spots are formed for the information track on the disc 90. This is the reproducing laser spot SPp1, SPp0, and SPp2 described in FIG. 8C and FIG.

Further, the reflected light of the three laser spots is incident on the photodetectors PD3, PD4, and PD5 of the light receiving element portion 46 via the optical systems of the objective lens 44, the spectroscope 43, and the multiple lens 45.

Here, the description will be made with the case of the example 2, but the other examples 1, the example 3, and the example 4 are also the same.

Fig. 25 is an example of a tracking servo using a plurality of laser spots, but shows an example of a reproducing optical system when the multi-beam LD 41 is not used.

The optical system in the optical pickup 1 is provided with an LD 51, a collimator lens 42, a spectroscope 43, a grating 52, a QWP (1/4 wavelength plate) 53, an objective lens 44, a multiple lens 45, a light receiving element portion 46, and two. Shaft mechanism 47.

The laser light emitted from the multi-beam LD 41 is collimated by the collimator lens 42 and passes through the spectroscope 43 to reach the grating 52.

The grating 52 can be a polarizing grating that is only diffracted toward the path, or a liquid crystal grating that can be turned ON/OFF.

The 3-beam optical system for reproduction can be formed by using the zero-order light and the ±first-order light obtained by the grating 52. Thereby, the reproducing laser spots SPp1 and SPp2 of FIG. 6C or the reproducing laser spots SPp1, SPp2, and SPp3 of FIG. 8C can be obtained.

The zero-order light and the ±first-order light are condensed by the object lens 44 via the QWP 53, and are irradiated onto the optical disk 90.

The reflected light from the optical disk 90 is transmitted through the objective lens 44, transmitted through the QWP 53 and the grating 52, and reflected by the spectroscope 43 to reach the multiple lens 45. Then, it is condensed by the multiple lens 45 and incident on the light receiving element portion 46.

In the light-receiving element portion 46, a photodetector that corresponds to the reproducing laser spots SPp1, SPp2, and SPp3 due to the zero-order light and the ±first-order light may be formed.

In addition, although the optical system for reproduction of the LD 51 having one light beam is disclosed in FIG. 25, a two-beam LD, a three-beam LD, or the like may be used to form an optical system that can be recorded and reproduced.

Figure 26 is a diagram showing an example of an optical system corresponding to the multilayer optical disc 90 of Figure 1B.

The basic structure is the same as the example of Fig. 25, but a beam expander lens 54 for spherical aberration correction is provided. The beam expander lens 54 is formed by a fixed lens 54a and a movable lens 54b. The movable lens 54b is variably located in the direction of the arrow V, that is, the direction of the optical axis.

The layer L corresponding to the target is driven to expand the lens 54 and to perform spherical aberration correction.

Furthermore, the grating 52 may be disposed between the beam expander lens 54 and the QWP 53, but may be disposed in the collimation as shown by the dashed grating 52A. Alternatively, the lens 42 and the beam splitter 43 may be used.

When the grating 52 is used, polarization dependence is required. However, when the grating 52A is used, polarization dependence is not required.

Fig. 27 is a view showing the multi-beam when the optical disk 90 forms three laser spots in the configuration of Fig. 26. Here, as an example of using the grating 52A.

The laser light output from the LD 51 is a zero-order light and a ±1st-order light by the grating 52A, and a multi-beam which forms three light spots is formed. Thereby, as the three laser spots irradiated to the layer L of the disc 90, the reproducing laser spots SPp1, SPp2, and SPp3 described in FIG. 8C can be obtained.

The reflected light of the laser spot is incident on the light receiving element portion 46 by the light beam shown in the drawing. Therefore, the light-receiving element portion 46 is configured to detect reflected light by, for example, the photodetector structure shown in Example 2 in FIG.

In the structure of FIG. 26, the configuration examples of FIGS. 23 and 25 are considered for the LD 51 and the light receiving element portion 46.

Further, in each of the examples of FIGS. 23, 25, and 26, it is also possible to independently provide the laser diode for reproduction and the laser diode for recording.

Fig. 28 is an optical system configuration of the optical disk 90 corresponding to the reference plane RL, as shown in Fig. 1C.

The LD 51, the collimator lens 42, the grating 52A, the spectroscope 43, the objective lens 44, the beam expanding lens 54, the multiple lens 45, and the light receiving element portion 46 are the same as those in Fig. 26.

At this time, setting the laser light of different wavelengths to be condensed on the reference plane RL Optical system.

That is, the LD 65, the collimator lens 66, the spectroscope 67, the beam expander 60, the dichroic 61, the two-wavelength QWP, and the wavelength selective aperture limiting element 62 are added.

The LD65 outputs laser light of a different wavelength from the LD51. For example, the LD 51 is a blue laser having a wavelength of 405 nm, and the LD 65 is, for example, a red laser having a wavelength of 650 nm. The laser light emitted from the LD 65 is collimated by the collimator lens 66, passes through the spectroscope 67, and is guided to the beam expander lens 60.

The beam expander lens 60 is formed by the fixed lens 60a and the movable lens 60b, and corrects the focus position so that the laser spot of the red laser light is focused on the reference surface RL.

Then, it is reflected by the dichroic chirp 61, and the λ/4 polarization and the aperture are restricted by the two-wavelength QWP and the wavelength selective aperture limiting element 62, and then the transmission lens 44 is irradiated to the reference plane RL of the optical disc 90.

The reflected light from the reference plane RL is transmitted through the object lens 44, the 2-wavelength QWP, and the wavelength selective aperture limiting element 62, the dichroic aperture 61, and the beam expander 60, and is reflected by the beam splitter 67 by the multi-lens 68. The light is incident on the light receiving element portion 69.

Furthermore, the laser light from the LD 51 as a blue laser passes through the collimator lens 66, the grating 52A, the beam splitter 43, the beam expander 54, the dichroic color 稜鏡 61, the 2-wavelength QWP, and the wavelength selective aperture limiting element. 62. The object lens 44 is irradiated to the layer L of the target of the optical disk 90. Then, the reflected light is an object lens 44, a 2-wavelength QWP, and a wavelength selective aperture limiting element 62, The system of the dichroic cylinder 61, the beam expanding lens 54, the spectroscope 43, and the multiple lens 45 is incident on the light receiving element portion 46.

At this time, the red laser light from the LD 65 and the blue laser light from the LD 51 are synthesized by the dichroic color 61, and guided to the objective lens 44.

The focus of the objective lens 44 is controlled in such a manner that the blue laser is focused on the target layer L. At this time, in order to focus the red laser on the reference plane RL, the movable lens 60b of the beam expander lens 60 is adjusted to the optical axis. Direction V2. For red laser light, the adjustment caused by the beam expander lens 54 and the aperture limitation by the 2-wavelength QWP and the wavelength selective aperture limiting element 62 are focused on the reference plane RL.

When such an optical system is used, information such as a concave track formed on the reference surface RL can be obtained based on the reflected light information obtained by the light receiving element portion 69. Therefore, as the tracking guidance information, the tracking servo operation of the objective lens 44 is performed, and recording or reproduction of the layer L by the blue laser can be performed.

Further, in the configuration of Fig. 28, it is also conceivable to use the multi-beam LD41 instead of the LD 51, and to separately provide the reproducing laser diode and the recording laser diode.

Next, Fig. 29A shows an example of the structure of an optical system when the servo laser spot SPp45 for astigmatism is used as shown in Fig. 7 .

As the optical system for irradiating the reproducing laser spots SPp1 and SPp2, the multi-beam LD41, the collimator lens 42, the spectroscope 43, the beam expander 54, the QWP 53, and the object lens 44 are provided. Further, a multiple lens 45 and a light receiving element portion 46 for receiving light of reflected light are provided.

In addition, for the irradiation of the laser spot SPp45 for servo, set There are an LD 70, a collimator lens 71, a 45° non-point beam diffractive element 72, and an optical path combining unit 73.

The laser light from the multi-beam LD 41 passes through the collimator lens 42, the optical path combining cymbal 73, the spectroscope 43, the beam expander 54, the QWP 53, and the objective lens 44, and is irradiated to the target layer L of the optical disk 90. Then, the reflected light is incident on the light receiving element portion 46 by the system of the objective lens 44, the QWP 53, the beam expander 54, the spectroscope 43, and the multiple lens 45.

On the other hand, the laser light from the LD 70 is incident on the 45° non-spot beam diffraction element 72 by the collimator lens 71 as parallel light.

The 45° non-spot beam diffractive element 72 is formed by generating a holographic pattern of astigmatism as shown in FIG. 29B, and is reversed with respect to each other for a pair of sub beams (±1 order light), and is given The wiring direction of the information recording track formed on the layer L of the optical disk 90 is an astigmatism of an angle of 45°.

The servo laser spot SPp45 described in Fig. 7 and the like has a laser spot having a 45° astigmatism. For this reason, the +1st order light or the -1st order light obtained from the 45° non-point beam diffractive element 72 may be used as the laser light for forming the servo laser spot SPp45.

Further, as the diffraction element which is not caused by the hologram pattern, a structure in which opaque aberration is imparted to the liquid crystal element may be employed.

The laser light from the 45° non-point beam diffractive element 72 for forming the servo laser spot SPp45 is formed by the optical path combining 稜鏡 73 and the laser light from the LD 70 (forming the reproducing laser spot SPp1, SPp2). The laser light is synthesized and irradiated to the optical disk 90 in the same path. In addition, the reflected light of the servo laser spot SPp45 is used for the laser spot for regeneration. The same path of SPp1 and SPp2 is guided to the light receiving element unit 46.

For example, by using such an optical system, a tangential push-pull signal obtained by imparting reflected light information of a servo laser spot SPp45 having an astigmatism angle of 45° is used as a tracking error, by using the The tracking servo control of the track error signal enables the reproducing laser spot SPp1 and SPp2 to fall on the information track to control the track, and the data can be reproduced according to the reflected light information.

Further, in the configuration of Fig. 29, the recording operation of Figs. 7A and 7B can be performed by using the laser light from which the recording power is output from the multi-beam LD 41 (or the LD 51 instead).

Of course, it is also possible to consider independently setting the laser diode for reproduction and the laser diode for recording.

<7. Modifications>

Although the embodiments have been described above, the techniques of the present invention are not limited to the examples of the embodiments, and various modifications can be considered.

The information recording track of the optical disk 90 is a multiple spiral structure such as a double spiral structure or a triple spiral structure. However, the structure may be a concentric circle.

That is, as the track of the concentric circle, it is assumed that the adjacent plurality of track groups are formed at the track pitch Tp1, and the track groups are separated from each other by the track pitch Tp2. Thereby, the information recording track shown in FIG. 2A, FIG. 3A, and FIG. 4A can be formed.

Further, in the case of the multiple spiral structure, the relationship between the number of spirals and the number of tracks separated by the track pitch Tp1 in the track group is not necessarily limited to the same number. the amount.

For example, FIG. 2, FIG. 3, and FIG. 4 are states in which the two orbits are in the orbit group in the double helix structure, the three orbits in the triplet structure, and the four orbits in the quadruple structure. To illustrate. However, the example shown in Figure 30 is also intended.

In the structure shown in Fig. 30A, as the orbits TKa, TKb, TKc, and TKd, a quadruple spiral structure is adopted.

Then, as shown in a part of FIG. 30B, the track pitch of each track of the tracks TKa and TKb is Tp1, and the track pitch of each track of the tracks TKc and TKd is also Tp1. On the other hand, the track pitch of each track of the track tracks TKb and TKc is Tp2.

In other words, at this time, "the orbital group adjacent to the plurality of orbits is a track pitch Tp1 which is shorter than the track pitch corresponding to the optical interception", and the combination of the tracks TKa and TKb and the combination of the tracks TKc and TKd. Therefore, the track group spacing TpG is the track group between the track groups TKa and TKb and the track group of the tracks TKc and TKd.

Although this example is a quadruple spiral structure, it is an example of a track group in which each of the two tracks becomes a track group, and the same information recording track structure as that of FIG. 2A is seen in the radial direction of the disk.

In this way, it is also possible to consider an example in which all the tracks of the multiple helix number are not set to the track group separated by the track pitch Tp1. In other words, as described above, the relationship between the number of spirals and the number of tracks separated by the track pitch Tp1 in the track group may not be the same.

Similarly, in the six-helix, there are also three orbitals with a track pitch of Tp1. An example in which two track groups are formed, or three track groups are formed by two tracks of each track pitch Tp1.

Moreover, the track pitch in the track group is not limited to a certain extent. For example, in FIG. 4, a track group is formed by four tracks, and each track in the track group is separated by a track pitch Tp1.

For example, in TK1, TK2, TK3, and TK4, the track pitch Tp1 is any between the tracks TK1 and TK2, between the tracks TK2 and TK3, and between the tracks TK3 and TK4. Here, the track pitch (Tp1) between the tracks TK1 and TK2, between the tracks TK2 and TK3, and between the tracks TK3 and TK4 may not necessarily be the same.

For example, there is a case where the track between TK1 and TK2 is 0.15 μm, the track between TK2 and TK3 is 0.20 μm, and the track between TK3 and TK4 is 0.15 μm.

Further, a plurality of types of arrangement of the laser spot irradiation positions described in FIG. 6, FIG. 7, and FIG. 8 are also conceivable. An example is disclosed in FIG. 31A is a modification of FIG. 6A, FIG. 31B is a modification of FIG. 7A, and FIG. 31C is a modification of FIG. 8A.

In FIG. 6A, the reproducing laser spots SPp1 and SPp2 used as the servos are set in the track line direction before the recording laser spots SPr1 and SPr2. As shown in FIG. 31A, the recording laser spots SPr1 and SPr2 may be in the state of the track line direction.

In FIG. 7A, the servo laser spot SPp45 is advanced before the recording laser spots SPr1 and SPr2. However, as shown in FIG. 31B, the recording laser spots SPr1 and SPr2 may be preceded by the track line direction.

In FIG. 8A, the reproducing laser spots SPp1, SPp0, and SPp2 used for the servo are set to be in the track line direction before the recording laser spots SPr1, SPr2, and SPr3, but this is as shown in FIG. 31C. It is also assumed that the recording laser spots SPr1, SPr2, and SPr3 are in the direction of the track line.

Moreover, although an optical disk is mentioned as an example of a recording medium, it is not limited to the disk-shaped recording medium. For example, even in a card-shaped recording medium such as an optical card, the track structure and the tracking servo method described in the embodiment can be applied.

Furthermore, the technology of the present invention can also adopt the following configuration.

(1) A reproducing method in which a recording medium is formed by an information recording track having a track pitch which is shorter than a track pitch which is optically interrupted by a wavelength of a laser light to be irradiated and an NA of an illumination optical system. a track group adjacent to the plurality of tracks, and a track group pitch in terms of the track group unit is longer than a track pitch corresponding to the optical block, and the recording medium performs the following operations: for the plurality of tracks in the track group Illuminating at least two reproducing laser spots, and using the differential signals of the respective radial contrast signals obtained by the information of the reflected lights of the two reproducing laser spots as tracking error signals, by using the tracking error The tracking servo control of the signal combines at least one or more of the reproducing laser spots to be placed on any of the information tracks, and the data is reproduced based on the reflected light information.

(2) The reproduction method according to the above (1), wherein n pieces of reproducing laser spots corresponding to the number of tracks n in the track group are irradiated, and by using two of the n laser spots The differential signals of the respective radial contrast signals obtained by the reflected light information are set as tracking error signals for tracking servo control, and the n reproducing laser spots are irradiated to n tracks in the track group, according to the irradiation The information of the reflected light of the reproducing laser spot is used to reproduce the information of each track.

(3) The reproduction method according to (1), wherein the information recording track of the recording medium is formed by a spiral multi-helical structure in which n tracks are independent, and the n tracks are used to form the aforementioned In the orbit group, the track group pitch of the track group adjacent to each other by the multiple spiral structure is longer than the track pitch corresponding to the optical breakage; and n reproductions corresponding to the number n of tracks in the track group are irradiated a laser spot, and using the differential signals of the respective radial contrast signals obtained by the information of the reflected light of the two of the n laser spots as the tracking error signal, the tracking servo control is performed, and the n The reproducing laser spot is used to track the state of each track, and is irradiated to n tracks in the track group, and the information of each track is reproduced based on the reflected light information of the laser spot for reproducing the irradiation.

(4) The reproducing method according to (3) above, wherein the information recording track is formed by a spiral double helix structure in which two independent tracks are formed, and the n=2.

(5) The reproduction method according to (3) above, wherein the information recording track has three independent spiral tracks formed in a spiral triple helix structure, and the n=3.

(6) The reproducing method according to any one of the above (1), wherein the reflected light information of the reproducing laser spot that falls on the information recording track by the tracking control is first performed. The sound cancellation process regenerates the data.

This application is based on the Japanese Patent Application No. 2011-113543 filed on May 20, 2011 by the Japanese Patent Office. The priority is claimed by reference to the contents of this application. case.

1‧‧‧ Optical pickup (optical head)

2‧‧‧Shaft motor

3‧‧‧ screw mechanism

4‧‧‧Matrix circuit

5‧‧‧Data Detection and Processing Department

6‧‧‧ crosstalk cancellation circuit

7‧‧‧Encoding/Decoding Department

8‧‧‧Host interface

10‧‧‧System Controller

100‧‧‧Host machine

11‧‧‧Optical block servo circuit

12‧‧‧Rotary axis servo circuit

13‧‧‧Laser driver

14‧‧‧Writing Strategy Department

17‧‧‧Rotary shaft drive

18‧‧‧Two-axis drive

19‧‧‧ Screw drive

31‧‧‧Differential Operation Circuit

33‧‧‧Photodetector

34‧‧‧Operating circuit

41‧‧‧Multiple beam LD

42,66,71‧‧‧ collimating lens

43,67‧‧‧ Spectroscope

44‧‧‧ object lens

45‧‧‧Multiple lenses

46,69‧‧‧Light-receiving components

47‧‧‧Two-axis mechanism

51,65,70‧‧‧LD

52, 52A‧‧ ‧ grating

53‧‧‧QWP

54,60‧‧‧beam expander lens

54a, 60a‧‧‧Fixed lens

54b, 60b‧‧‧ movable lens

61‧‧‧Dual color

62‧‧‧ Wavelength selective opening limiting element

72‧‧‧45° non-point beam diffractive element

73‧‧‧Light path synthesis

90‧‧‧Recording Media (CD-ROM)

91‧‧‧Volume layer

92‧‧‧ Coverage

93‧‧‧Substrate

A, B, C, D‧‧‧ light surface

RL‧‧‧ reference surface

L0...Ln‧‧‧ layer

TK1~12, TKa, TKb, TKc, TKd‧‧ track

TKG1, TKG2‧‧‧ guided orbit

Tp1, Tp2‧‧‧ track spacing

TpG, TpG2‧‧‧ Track group spacing

SPp0~3‧‧‧Renewable laser spot

SPr, SPr1~3‧‧‧ Recording laser spot

SPp45‧‧‧ Servo laser spot

S0, S1, S2‧‧‧ reflected light signal

TE‧‧‧Tracking error signal

TK-BL‧‧‧balance control signal

PD1~15‧‧‧Photodetector

Fig. 1 is an explanatory diagram showing a configuration example of a recording medium according to an embodiment of the present invention.

Fig. 2 is an explanatory view of a double spiral track structure of the embodiment.

Fig. 3 is an explanatory view of a track structure of a triple helix of the embodiment.

Fig. 4 is an explanatory view of a track structure of a quadruple spiral according to an embodiment.

Fig. 5 is a block diagram of a disk drive device according to an embodiment.

Fig. 6 is an explanatory diagram showing an example of a recording/reproduction method by two reproduction spots + recording spots in the embodiment.

Fig. 7 is an explanatory diagram showing an example of a recording/reproduction method by an astigmatism spot + recording (reproduction) spot of the embodiment.

[Fig. 8] Recording caused by the reproduction spot + recording spot of the third embodiment An illustration of the birth mode example.

Fig. 9 is an explanatory diagram showing an example of a recording means in the embodiment.

[Fig. 10] An explanatory diagram of a signal obtained by a previous optical disc.

[Fig. 11] An explanatory diagram of the influence of the signal of the narrow track pitch.

Fig. 12 is an explanatory diagram of optical occlusion.

Fig. 13 is an explanatory diagram of a signal modulated in the embodiment.

Fig. 14 is an explanatory diagram of the detection sensitivity of the signal modulated in the embodiment.

Fig. 15 is an explanatory diagram of a tracking method by two light spots in the embodiment.

Fig. 16 is an explanatory diagram of a recording operation by tracking using two spots of the embodiment.

Fig. 17 is an explanatory diagram of a tracking method by astigmatism spots of the embodiment.

FIG. 18 is an explanatory diagram of a recording operation using tracking by the astigmatic aberration spot of the embodiment. FIG.

Fig. 19 is an explanatory diagram of a tracking method by two light spots at the time of three-spot irradiation in the embodiment.

FIG. 20 is an explanatory diagram of a recording operation using tracking by the astigmatic aberration spot of the triple helix trajectory of the embodiment. FIG.

Fig. 21 is an explanatory diagram of a tracking mode at the time of three-spot irradiation in a state where there is no central track in the embodiment.

FIG. 22 is an explanatory diagram of a tracking method by two light spots when the pitch of the track is further reduced.

Fig. 23 is an explanatory diagram of an optical system structure example of the embodiment.

Fig. 24 is an explanatory diagram of a multiple beam of an optical system configuration example of Fig. 23;

Fig. 25 is an explanatory diagram of an optical system structure example of the embodiment.

Fig. 26 is an explanatory diagram of an optical system structure example of the embodiment.

FIG. 27 is an explanatory diagram of a multiple beam of an optical system configuration example of FIG. 26. FIG.

Fig. 28 is an explanatory diagram of an optical system structure example of the embodiment.

Fig. 29 is an explanatory diagram of an optical system structure example of the embodiment.

Fig. 30 is an explanatory diagram showing a modification of the structure of the recording medium track of the embodiment.

Fig. 31 is an explanatory diagram showing a modification of the positional relationship of the laser spot irradiation in the embodiment.

Tp1, Tp2‧‧‧ track spacing

TpG‧‧‧ Track group spacing

SPp1, SPp2‧‧‧Renewable laser spot

TE‧‧‧Tracking error signal

TK-BL‧‧‧balance control signal

S1, S2‧‧‧ reflected light signal

6‧‧‧ crosstalk cancellation circuit

31‧‧‧Differential Operation Circuit

TKx, TKx+1‧‧ track

A, B, C‧‧‧ light surface

Claims (8)

A reproducing method, wherein the recording medium is formed by a plurality of track abutments at a track pitch which is shorter than a track pitch corresponding to an optically interrupted track defined by a wavelength of the irradiated laser light and an NA of the illumination optical system. The track group, and the track group pitch in terms of the track group unit is longer than the track pitch corresponding to the optical block, and is characterized in that the recording medium performs the following operation: for the plural in the track group Orbiting, irradiating at least two reproducing laser spots, and using the differential signals of the respective radial contrast signals obtained by the information of the reflected light of the two reproducing laser spots as a tracking error signal, by using the tracking The tracking servo control of the error signal combines at least one or more reproducing laser spotes onto the information recording track, and reproduces the data based on the reflected light information. The reproducing method according to claim 1, wherein the n reproducing laser spots corresponding to the number of tracks n in the track group are irradiated, and each of the n laser spot points is used. The differential signal of each radial contrast signal obtained by the reflected light information is set as a tracking error signal for tracking servo control, and the n reproducing laser spots are irradiated to n tracks in the track group, and the regeneration is performed according to the irradiation. Anti-ray spot Light information to reproduce information on each track. The reproducing method according to the first aspect of the invention, wherein the information recording track of the recording medium is formed by a spiral multi-spiral structure in which n independent tracks are formed, and the track is formed by the n tracks. The group of the above-mentioned orbital groups adjacent to each other by the multiple spiral structure is spaced apart from each other by a distance corresponding to the optically interrupted orbital distance; and the plurality of reproducing thunders corresponding to the number n of the orbits in the orbital group are irradiated Shooting light points, and using the differential signals of the respective radial contrast signals obtained by the information of the reflected light of the two of the n laser light spots as tracking error signals to perform tracking servo control, the n regenerations are performed. The laser spot is used to track the state of each track, and the n tracks in the track group are irradiated, and the information of each track is reproduced based on the reflected light information of the laser spot for reproducing the irradiation. The reproducing method according to claim 3, wherein the information recording track is formed by a spiral double spiral structure, and the n=2. The reproducing method according to claim 3, wherein the information recording track is formed by a spiral triple helix structure, and the n=3. The regeneration method as recited in claim 1, wherein For the reflected light information of the reproducing laser spot falling on the information track by the combined track control, the crosstalk canceling process is first performed to regenerate the data. A reproducing apparatus characterized by comprising: an optical head having a track pitch shorter than an optically occluded track pitch corresponding to a wavelength of a laser beam to be irradiated to an optical system according to a wavelength of the laser light to be irradiated to the information recording track; And forming a track group adjacent to the plurality of tracks, and the track group pitch in the unit of the track group is a recording medium longer than the track pitch corresponding to the optical block, and is irradiated by at least two reproducing laser spots. In the method, the laser light is irradiated through the object lens to obtain information about the reflected light of each laser spot; and the servo circuit portion is a difference of the radial contrast signals obtained by the information of the reflected light of the two reproducing laser spots. The signal is set as a tracking error signal, and by using the tracking servo control of the tracking error signal, the optical head performs at least one or more reproducing laser spot to be combined and falls on any information recording track. The track operation and the reproduction circuit unit reproduce the data based on the reflected light information of the reproducing laser spot that falls on the information track by the mesh control. The reproduction device according to claim 7, further comprising: a crosstalk canceling unit that performs crosstalk cancellation on the reflected light information of the reproducing laser spot that falls on the information track by the mesh control Processing; the regenerative circuit unit is configured to perform stringing based on the crosstalk canceling unit The sound cancels the reflected light information to regenerate the data.