WO2014021295A1

WO2014021295A1 - Guide-layer-separated optical recording medium and optical recording device

Info

Publication number: WO2014021295A1
Application number: PCT/JP2013/070544
Authority: WO
Inventors: 賢一下舞; 今村　裕
Original assignee: 太陽誘電株式会社
Priority date: 2012-07-31
Filing date: 2013-07-30
Publication date: 2014-02-06
Also published as: JP2014029748A; TW201411613A

Abstract

[Problem] To enable stable tracking control falling between the switching of the polarity of a tracking servo. [Solution] This optical recording device records at an optical recording medium that has at least one recording layer and a guide layer provided as a guide track at which a land section and a groove section are helically continuous and is provided with a flag region at which a flag signal is recorded for generating the timing of switching points immediately prior to the switching points of the groove section and the land section in the recording direction in the guide track. An optical pickup radiates guide light at the guide track of the guide layer, and receives returning light. A tracking control unit performs tracking control by generating a tracking error signal on the basis of the received light signal. A flag processing unit generates the timing of the switching points by detecting a flag signal on the basis of the received light signal, and reverses the polarity of tracking control at said timing.

Description

Guide layer separation type optical recording medium and optical recording apparatus

The present invention relates to a guide layer separation type optical recording medium having a land / groove structure guide layer and an optical recording apparatus for recording on the guide layer separation type optical recording medium.

For the purpose of increasing the capacity of an optical disk such as a DVD (Digital Versatile Disk) or a Blu-ray Disc (registered trademark), the recording layer is multi-layered. Along with the increase in the number of recording layers, there is also known a system in which track king control at the time of recording or reproducing data on a recording layer is performed using a guide track provided in a layer different from the recording layer. *

For example, tracking control is performed on a guide track layer provided with a guide track having a groove structure using light having a wavelength of 390 nm to 420 nm (blue), and one recording layer among a plurality of recording layers is 650 nm to 680 nm. There is an optical drive device that performs recording using light of the wavelength (red) (for example, Patent Document 1). *

Further, as a system for increasing the recording capacity per recording layer, there is a land / groove recording system in which marks are recorded on both lands and grooves. In this land / groove recording method, the pitch can be narrowed by using the tracking control method employed in the method of recording only in the groove portion. *

Generally, a track of an optical recording medium such as a DVD or a Blu-ray is provided in a spiral shape. Therefore, in the tracking control method, the tracking target for causing the laser spot from the optical pickup to follow the track is periodically switched between the land portion and the groove portion. At this time, the tracking servo polarity is reversed between the land portion and the groove portion. *

FIG. 14 shows a case where a PP (push-pull) method or a DPP (differential push-pull) method is employed as a tracking control method, when the laser spot is on the groove portion (during groove on track) and on the land portion. FIG. 6 is a diagram illustrating a relationship between an off-track amount and a tracking error signal when the track is at a land (on land-on-track). *

Here, the tracking servo is control for moving the laser spot in a direction orthogonal to the direction along the track so that the tracking error signal becomes zero. At the time of groove on track, the polarity of the tracking error signal becomes positive when the laser spot is shifted to the left side from the center of the groove. Therefore, by moving the laser spot to the right and positioning it at the center of the groove, the value of the tracking error signal gradually approaches 0 from a positive value. *

On the other hand, at the time of land-on-track, the polarity of the tracking error signal becomes positive when the laser spot is shifted to the right side from the center of the land. Accordingly, by moving the laser spot to the left and positioning it at the center of the land, the value of the tracking error signal gradually approaches 0 from a positive value. *

Due to the above circumstances, in the land / groove recording method, it is necessary to switch the polarity of the tracking servo between when the laser spot is on the groove portion and on the land portion. In particular, in the case of a structure in which lands and grooves are switched while tracks are spirally continuous, tracking becomes unstable if there is a deviation in the timing of switching the polarity of the tracking servo. *

In Patent Document 2, in an optical disk medium in which land areas and groove areas are alternately provided for each track, a unique signal pattern indicating the presence of a header area is recorded at the head of each of the land area and the groove area. A technique for detecting the unique signal pattern and switching the polarity of the tracking servo is disclosed.

JP 2007-200197 A JP-A-10-154355

However, the one disclosed in Patent Document 2 assumes a physical format in which the land group structure is interrupted in the header area. Therefore, it is sufficient that the switching of the tracking servo polarity is completed within the header area. *

On the other hand, in the case of an optical recording medium that employs a continuous physical format with the land / group structure spirally uninterrupted, the polarity of the tracking servo can be switched at the switching point between the land and groove. Unless it is performed with high accuracy, stable tracking cannot be expected. Therefore, with the method of simply detecting the unique signal pattern and switching the polarity of the tracking servo, it is not always possible to switch the polarity of the tracking servo at a timing that is expected with high accuracy, and stable switching with the switching of the polarity of the tracking servo in between Tracking is not guaranteed. *

Further, it is assumed that the guide layer separation type multilayer optical disc is provided as physical address information recorded on the guide track of the guide layer by wobble or the like. Prior to recording user data on the recording layer, the optical recording apparatus for recording on the guide layer separation type multilayer optical disc demodulates the physical address information from the wobble signal, and specifies the physical address information and the information for specifying the recording layer. From this, it is assumed that the logical address given to the data unit recorded in the recording layer is calculated. *

In such an assumption, when a flag signal for giving a timing for switching the polarity of the tracking servo to the guide track of the guide layer is recorded by wobble or the like, the flag signal is inserted into the physical address information of the guide track. Missing period. For this reason, a logical address given to the data unit recorded in the recording layer cannot be generated during the missing period, and there is a problem that a continuous logical address cannot be correctly given to the data in the recording layer. *

In view of the circumstances as described above, an object of the present invention is to enable stable tracking control with switching the polarity of the tracking servo, and to continuously give a logical address to data recorded on the recording layer. Another object is to provide a guide layer separation type optical recording medium and an optical recording apparatus.

In order to achieve the above object, a guide layer separation type optical recording medium according to an embodiment of the present invention includes one or more recording layers, a guide layer provided as a guide track in which land portions and groove portions are spirally continuous, and And a flag area in which a flag signal for causing the optical recording device to generate the timing of the switching point immediately before the switching point between the land portion and the groove portion in the recording direction is recorded in the guide track. Is provided. *

The flag signal may be recorded by wobbling the guide track. Alternatively, the flag signal may be recorded by a pit row. *

An optical recording apparatus according to another aspect of the present invention includes one or more recording layers capable of recording information, and a guide layer provided as a guide track in which land portions and groove portions are spirally continuous, The guide track is provided with a flag area in which a flag signal for generating the timing of the switching point in the optical recording apparatus is recorded immediately before the switching point between the land portion and the groove portion in the recording direction. An optical recording apparatus that performs recording on a layer-separated optical recording medium, wherein a laser beam is applied to the guide track of the guide layer of the driven optical recording medium and a driving unit that drives the guide layer-separated optical recording medium And an optical pickup having a guide optical system that receives reflected light of the guide light and converts it into a received light signal, and a trap based on the received light signal. A tracking control unit that generates a tracking error signal and performs tracking control, detects the flag signal based on the received light signal, generates the timing of the switching point, and sets the polarity of the tracking control at the generated timing. And a flag processing unit that sequentially inverts. *

According to this optical recording apparatus, the polarity of the tracking servo can be accurately switched at the switching point between the land portion and the groove portion, and stable tracking control can be performed with the switching of the polarity of the tracking servo. *

The optical recording apparatus further includes a clock generation unit that generates a reference clock based on the light reception signal, and the flag processing unit detects the flag signal after detecting the flag signal based on the light reception signal. And the time when the count value reaches a predetermined value may be generated as the timing of the switching point. *

The flag signal may be recorded as a predetermined wobble of the guide track, and the flag processing unit may detect the flag signal recorded as the predetermined wobble based on the light reception signal. *

The flag signal may be recorded as a predetermined pit row on the guide track, and the flag processing unit may detect the flag signal recorded as the predetermined pit row based on the light reception signal. *

Further, the optical recording apparatus includes a control unit that controls to stop recording on the recording layer from when the flag signal is detected by the flag processing unit until the timing of the switching point is generated It may further comprise. This ensures the acquisition of physical address information necessary for generating the logical address to be given to the data recorded on the recording layer, and can continuously give the logical address to the data recorded on the recording layer. *

Alternatively, the optical recording apparatus is a control unit that performs control to record dummy data on the recording layer from when the flag signal is detected by the flag processing unit to when the timing of the switching point is generated It may further comprise.

As described above, according to the present invention, stable tracking control with switching of the polarity of the tracking servo becomes possible, and logical addresses can be continuously given to data recorded on the recording layer.

1 is a diagram showing an optical recording system according to an embodiment of the present invention. It is a figure which shows the relationship between the storage unit, the optical disk, and drive unit in the optical recording system of FIG. It is sectional drawing which shows the structure of the optical disk which is a guide layer separated type optical recording medium. FIG. 4 is a plan view showing a guide track of a guide layer of the optical disc in FIG. 3. FIG. 5 is a diagram illustrating a structure around a switching point between a land portion and a groove portion in the guide track of FIG. 4. It is a figure which shows the structure of a polarity inversion flag area | region. It is a figure which shows the structure of the disk drive in the optical recording system of FIG. FIG. 8 is a block diagram illustrating a specific configuration of a wobble playback unit and a flag processing unit in the disk drive of FIG. 7. FIG. 5 is a diagram showing a modification of the structure around a switching point between a land portion and a groove portion in the guide track of FIG. 4. It is a figure which shows the structure of the disk drive which is a modification. FIG. 11 is a block diagram illustrating a specific configuration of a wobble reproduction unit and a pit string flag processing unit in the disk drive of the modified example of FIG. It is a figure which shows the relationship between the physical address of the data area of a guide layer, and the logical address allocated to the data area of each recording layer. It is a figure which shows the specific allocation of a logical address. It is a figure which shows the relationship between the amount of off-tracks at the time of groove on track and land on track, and a tracking error signal in PP method or DPP method.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an optical recording system according to an embodiment of the present invention. *

FIG. 1 is a diagram showing the overall configuration of an optical recording system. The optical recording system 1 includes a storage unit 10, a disk transport mechanism 20, a drive unit 30, a RAID controller 40, and a host device 50. Details of each will be described below.

[Storage Unit 10] The storage unit 10 is a unit in which a plurality of optical disks 11 (guide layer separation type optical recording media) are individually detachably accommodated. *

As a storage form of the plurality of optical disks 11 in the storage unit 10, flat stacking, vertical alignment, and the like are assumed. In any case, it is preferable that a certain gap is provided between the adjacent optical disks 11 so that the optical disk 11 can be smoothly inserted into and removed from the storage unit 10. The shape of the storage unit 10 is assumed to be, for example, a rectangular parallelepiped shape or a cylindrical shape from the viewpoint of handling by the user and the storage efficiency of the optical disk 11. In the example of FIG. 1, a rectangular parallelepiped storage unit 10 in which a plurality of optical disks 11 are accommodated in a flat stack is used. *

FIG. 2 is a diagram illustrating the configuration of the storage unit 10, the optical disk 11, and the drive unit 30. At least one side surface of the storage unit 10 is provided with an opening 101 for inserting and removing the optical disk 11 and a door (not shown) for opening and closing the opening 101. The door is opened / closed in conjunction with the operation of loading / unloading the optical disk 11 from / to the storage unit 10 by the disk transport mechanism 20, and is closed at other times. *

In the present invention, the configuration of the storage unit 10 is not limited to that shown in FIG. Various modifications such as the shape of the storage unit 10, the number and position of the openings, the presence / absence of a door, and the accommodation form of a plurality of optical disks 11 are possible. *

[Optical Disc 11] The optical disc 11 accommodated in the storage unit 10 is a so-called “guide layer separation type optical recording medium” in which a guide layer and a recording layer are separated into separate layers. *

(Cross-Sectional Structure of Optical Disc 11) FIG. 3 is a cross-sectional view showing the structure of the optical disc 11. The optical disc 11 has a guide layer 112 and one or more recording layers 113. In the example of the optical disk 11 in the figure, the number of recording layers 113 is “4”. An intermediate layer 114 having optical transparency is interposed between the guide layer 112 and the recording layer 113 closest to the guide layer 112 and between the adjacent recording layers 113. These layers are the protective layer 115, the recording layer 113, the intermediate layer 114, the recording layer 113, the intermediate layer 114, the recording layer 113, the intermediate layer from the side on which the recording / reproducing light R1 and the guide light R2 from the optical pickup 32 are incident. The layer 114, the recording layer 113, the intermediate layer 114, and the guide layer 112 are stacked in this order. *

A guide track 121 having a land / groove structure is spirally provided on the surface of the guide layer 112 facing the recording layer 113. On the side wall surface of the guide track 121, physical address information indicating position information over the entire circumference of the disk is recorded by wobble. The guide track 121 is formed with a track pitch (0.64 μm) corresponding to, for example, red laser light used for recording / reproduction of a DVD (Digital Versatile Disk). The average pitch between the land and the groove is 0.32 μm. Hereinafter, the laser beam of the red laser beam is referred to as “guide light”. *

In this embodiment, since land / groove recording is assumed, the land portion and the groove portion are used as a guide track 121 having a spiral shape. Therefore, the pitch of the guide track 121 is 0.32 μm. *

For tracking of the guide track 121 of the guide layer 112, a laser beam having a red wavelength (second wavelength) used for recording / reproduction of a DVD (Digital Versatile Disk) is used. Hereinafter, the laser light having the second wavelength may be referred to as “guide light”. *

In the optical recording system 1 of the present embodiment, tracking control by, for example, a differential push-pull method (DPP: Differential Push-Pull) is performed in each of the land portion and the groove portion of the guide track 121. By performing tracking control in each of the land portion and the groove portion of the guide track 121, information recording on the recording layer 113 can be performed at a track pitch of 0.32 μm. *

Since the guide track 121 is provided in a spiral shape, the tracking target for causing the guide light spot from the optical pickup to follow the guide track 121 is switched alternately between the land portion and the groove portion. Since the tracking servo polarity is reversed between the land and groove, stable tracking control is possible unless the switching point between the land and groove is detected as accurately as possible and the tracking servo polarity is reversed. Can not expect. *

In the present embodiment, in order to solve such a problem, the following physical format is adopted for the guide track 121. *

(Structure of the guide track 121) FIG. 4 is a plan view showing the guide track 121 of the guide layer 112 of the optical disc 11, and FIG. 5 is an enlarged view of the structure around the switching point between the land portion and the groove portion in the guide track 121 of FIG. FIG. *

For example, it is assumed that the land portion and the groove portion are switched at a cycle of one rotation of the optical disc 11. In this case, the switching point between the land portion and the groove portion is arranged on one radiation from the center point of the optical disc 11. As shown in FIG. 5, with respect to the recording direction, a polarity inversion flag region 122 is provided immediately before the switching point between the land portion and the groove portion. *

FIG. 6 is a diagram showing the structure of the polarity inversion flag region 122. As shown in the figure, in the polarity reversal flag area 122, a flag signal for causing the disk drive 31 to generate the timing of the switching point between the land portion and the groove portion is recorded as, for example, a wobble of the guide track 121. Yes. Hereinafter, the wobble recorded as the flag signal is referred to as “flag wobble”. *

The areas other than the polarity inversion flag area 122 of the guide track 121 are areas used for tracking control, acquisition of physical address information, recording clock generation, and the like when recording on the recording layer 113. This area is referred to as a “data area 123”. I will call it. In the data area 123, physical address information is recorded as wobble. Hereinafter, the wobble in the data area 123 is referred to as “data wobble”. *

The data wobble and the flag wobble are formed with different frequencies or amplitudes so that the disk drive 31 can discriminate between the data wobble and the flag wobble. FIG. 6 shows a case where a difference is made in the frequency of the data wobble and the flag wobble. In this case, the flag wobble cycle W1 is set to a value sufficiently smaller than the data wobble cycle W0 so that the disk drive 31 can reliably and quickly discriminate between the data wobble and the flag wobble. In FIG. 6, the flag wobble cycle W1 is depicted as being several times lower than the data wobble cycle W0, but may be several tens of times lower or even lower. If the flag wobble cycle W1 is not set to a value sufficiently lower than the data wobble cycle W0, it is difficult to reliably distinguish the flag wobble from the data wobble, and the timing of the switching point is generated with high accuracy. It's also difficult. Further, it takes time until the disk drive 31 determines the detection of the flag wobble, and the length of the polarity reversal flag area 122 is required accordingly, so that the overall recording capacity is reduced. Therefore, it is desirable that the flag wobble cycle W1 is set to a value sufficiently lower than the data wobble cycle W0. *

However, in the present invention, the physical condition of the flag wobble is not limited to the above. For example, even if the flag wobble period W1 is larger than the data wobble period W0, the meaning of satisfying the role of the flag signal for causing the disk drive 31 to generate the switching point timing between the land part and the groove part is satisfied. Then it is effective. Alternatively, a structure in which the polarity reversal flag region 122 is not intentionally wobbled is also conceivable. The above is the description of the guide layer 112. *

The recording layer 113 is a layer on which information is recorded with a track pitch of 0.32 μm using a laser beam having a blue wavelength (first wavelength) used for recording and reproduction of a Blu-ray Disc (registered trademark), for example. Hereinafter, the laser light having the first wavelength may be referred to as “recording / reproducing light” or “recording light”. *

The recording layer 113 is composed of, for example, a light absorption layer and a reflection layer. As the light absorption layer, organic dyes such as cyanine dyes and azo dyes, and inorganic materials such as Si, Cu, Sb, Te, and Ge are used. When the target recording layer 113 in the optical disc 11 is irradiated with the recording light, the reflectance of the region irradiated with the recording light changes, and the region with the changed reflectance is formed as a pit, so that the recording layer 113 is formed. Information is recorded in *

Since tracking control and physical address information at the time of recording and reproducing information on the recording layer 113 and acquisition of a recording clock such as a recording clock are performed using the wobble signal of the guide track 121 of the guide layer 112, The recording layer 113 does not require the guide track 121 having a land / groove structure. Therefore, the surface of the recording layer 113 may be flat. *

[Disk transport mechanism 20] The disk transport mechanism 20 takes out the target optical disk (guide layer separation type optical recording medium) 11 from the storage unit 10 and loads it into the disk drive 31 in the drive unit 30, or conversely from the disk drive 31. This is a mechanism for returning the ejected optical disk 11 to the storage unit 10. *

For example, the disk transport mechanism 20 can take out a plurality of optical disks 11 from the storage unit 10 at the same time and separately load them into a plurality of disk drives 31 in the drive unit 30. It is desirable to have a mechanism. *

[Drive unit 30] A plurality of disk drives 31 are mounted in the drive unit 30. In the example of FIG. 5, five disk drives 31 are mounted. The number of optical disks 11 accommodated in the storage unit 10 and the number of disk drives 31 mounted in the drive unit 30 are not necessarily the same. *

(Configuration of Disk Drive 31) FIG. 7 is a diagram showing the configuration of the disk drive 31. The disk drive 31 includes an optical pickup 32. The optical pickup 32 includes a first optical system corresponding to the recording / reproducing light and a second optical system corresponding to the guide light. *

The first optical system includes a first light source 33, a first collimator lens 34, a first polarizing beam splitter 35, a first relay lens 36, a second collimator lens 37, a combining prism 38, and a quarter wavelength. The plate 39, the objective lens 60, the first light receiving lens 61, the first light receiving unit 62, and the like are included. Here, the synthesis prism 38, the quarter wavelength plate 39, and the objective lens 60 belong to both the first optical system and a second optical system described later. *

The first light source 33 includes a laser diode that emits laser light having a first wavelength as recording / reproducing light R1. The recording / reproducing light R 1 emitted from the first light source 33 is converted into parallel light by the first collimator lens 34, and passes through the first polarization beam splitter 35, the first relay lens 36 and the second collimator lens 37. The light enters the combining prism 38. The synthesizing prism 38 matches the optical axes of the recording / reproducing light R1 incident from the second collimator lens 37 and the guide light R2 incident from a third collimator lens belonging to the second optical system described later. Are combined and made incident on the objective lens 60 via the quarter-wave plate 39. The incident recording / reproducing light is condensed by the objective lens 60 so as to be focused on the target recording layer 113 of the optical disk 11. *

The recording / reproducing light (returned light) reflected by the recording layer 113 is incident on the combining prism 38 via the objective lens 60 and the quarter wavelength plate 39, and is transmitted through the combining prism 38 in the incident direction. Return to the first polarization beam splitter 35 via the collimator lens 37 and the first relay lens 36. The first polarization beam splitter 35 reflects the return light of the first wavelength from the first relay lens 36 at an angle of about 90 degrees and passes through the first light receiving lens 61 to the first light receiving unit 62. Make it incident.

The first light receiving unit 62 is composed of a light receiving element whose light receiving surface is divided into four in the disk radial direction and the tangential direction, and outputs a voltage signal of a level corresponding to the light receiving intensity for each of the divided light receiving surfaces. Is output to the equalizer 75 as a reproduction signal of the recording data, and a voltage signal for each divided light receiving surface is output to a focus error generation unit (not shown). *

The second optical system includes a second light source 63, a third collimator lens 64, a second polarizing beam splitter 65, a second relay lens 66, a fourth collimator lens 67, a combining prism 38, and a quarter wavelength. The plate 39, the objective lens 60, the second light receiving lens 68, the second light receiving portion 69, and the like. *

The second light source 63 emits guide light R2 having a second wavelength. The guide light R2 emitted from the second light source 63 is converted into parallel light by the third collimator lens 64, and is combined through the second polarization beam splitter 65, the second relay lens 66, and the fourth collimator lens 67. The light enters the prism 38. As described above, the guide light R2 incident on the combining prism 38 and the optical axis of the recording / reproducing light R1 having the first wavelength incident on the combining prism 38 from the second collimator lens 37 of the first optical system. Are made to coincide with each other and enter the objective lens 60 via the quarter-wave plate 39. The incident guide light R2 is collected by the objective lens 60 so as to be focused on the guide layer 112 of the optical disk 11. *

The guide light R2 (return light) reflected by the guide layer 112 enters the synthesis prism 38 through the objective lens 60 and the quarter wavelength plate 39, and is reflected by the synthesis prism 38 at an angle of about 90 degrees. Returning to the second polarizing beam splitter 65 via the fourth collimator lens 67 and the second relay lens 66. The second polarization beam splitter 65 reflects the return light of the guide light R2 from the second relay lens 66 at an angle of about 90 degrees, and passes through the second light receiving lens 68 to the second light receiving unit 69. Make it incident. *

The second light receiving unit 69 is, for example, a light receiving element whose light receiving surface is divided into two in the disk radial direction orthogonal to the track, a light receiving element whose light receiving surface is divided into four in the disk radial direction and the tangential direction, or light receiving A main light-receiving element whose surface is divided into at least two parts and a combination of two sub-light-receiving elements divided into two parts are arranged on both sides of the main light-receiving element in the tangential direction. The second light receiving unit 69 selectively outputs a voltage signal having a level corresponding to the received light intensity of each divided light receiving surface to the tracking control unit 71 and the wobble reproduction unit 78. *

The optical pickup 32 is provided with a tracking actuator 70 and a focusing actuator (not shown). The tracking actuator 70 moves the objective lens 60 in the disk radial direction based on the tracking drive signal from the tracking control unit 71. The focusing actuator moves the objective lens 60 in the optical axis direction by a focus drive signal from a focus control unit (not shown). *

Further, although not shown, the optical pickup 32 includes a first relay lens actuator that moves the first relay lens 36 in the optical axis direction so as to switch the recording layer 113 irradiated with the recording / reproducing light, and a first relay lens actuator. A second relay lens actuator for moving the second relay lens 66 in the optical axis direction is provided. The above is the description of the optical pickup 32. *

In addition to the optical pickup 32 described above, the disk drive 31 includes a data modulating unit 72, a first light source driving unit 73, a second light source driving unit 74, an equalizer 75, a data reproducing unit 76, a tracking control unit 71, a wobble. The reproduction unit 78, the disk motor driving unit 79, the feed mechanism 80, the disk motor control unit 81, the controller 82, the flag processing unit 83, and a focus error generation unit, a focus control unit, a relay lens control unit, and the like (not shown) are included. *

The data modulator 72 modulates the recording data supplied from the controller 82 into a bit string signal suitable for forming a recording mark, and supplies the modulated signal to the first light source driver 73. *

The first light source drive unit 73 generates a drive pulse for driving the first light source 33 based on the modulation signal from the data modulation unit 72. *

The equalizer 75 performs binarization at a predetermined slice level after performing an equalization process such as PRML (Partial Response Maximum Likelihood) on the reproduction RF signal from the first light receiving unit 62. *

The data reproduction unit 76 demodulates data from the binary signal output from the equalizer 75, performs decoding processing such as error correction from the demodulated data, generates reproduction data, and supplies the reproduction data to the controller 82. *

The tracking control unit 71 generates a tracking error signal by, for example, the PP (push-pull) method or the DPP (differential push-pull) method based on the voltage signal of each divided light receiving surface of the second light receiving unit 69. Then, a tracking drive signal to be supplied to the tracking actuator 70 is generated based on the tracking error signal. Further, the tracking control unit 71 receives the tracking servo polarity switching signal from the flag processing unit 83, and the polarity of the tracking drive signal, that is, the direction in which the objective lens 60 is moved is the + direction of the disk radial direction (the direction toward the disk outer periphery). And-direction (direction toward the inner circumference of the disc). *

The wobble reproduction unit 78 reproduces a wobble signal based on the output of the second light receiving unit 69, discriminates the reproduced wobble signal into a data wobble signal and a flag wobble signal based on the frequency, etc. Address information is demodulated and supplied to the controller 82. The wobble reproduction unit 78 generates a reference recording clock from the data wobble signal. Further, the wobble reproduction unit 78 supplies the discriminated flag wobble signal to the flag processing unit 83. *

The flag processing unit 83 detects the polarity inversion flag region 122 based on the flag wobble signal supplied from the wobble reproduction unit 78, generates the switching point timing between the land portion and the groove portion, and at the generated timing. A tracking servo polarity switching signal is supplied to the tracking control unit 71 and the controller 82. The specific configuration and operation of the flag processing unit 83 will be described later. *

The disk motor drive unit 79 supplies a drive signal to a disk motor 85 that rotates the optical disk 11 under the control of the disk motor control unit 81. *

The feed mechanism 80 is a mechanism for transporting the optical pickup 32 in the radial direction of the optical disc 11. *

A focus control unit (not shown) supplies a focus drive signal to the focusing actuator based on a focus error signal from a focus error generation unit (not shown) to move the objective lens 60 in the optical axis direction. *

The controller 82 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. The controller 82 controls the entire disk drive 31 based on a program loaded in the main memory area allocated to the RAM. *

A plurality of the disk drives 31 described above are mounted on the drive unit 30 and can be controlled independently, and information can be recorded and reproduced on the loaded optical disk 11 simultaneously. *

[RAID Controller 40] A RAID (Redundant Arrays of Inexpensive Disks) controller 40 records data in multiple on one or more disk drives 31 in the drive unit 30 in response to a recording command from the host device 50, or performs striping. RAID control to record in a distributed manner is performed. *

The controller 82 of each disk drive 31 to which the recording or reproducing instruction is given from the RAID controller 40 performs control for recording or reproducing data on the optical disk 11. *

[Host device 50] The host device 50 is the highest-level device that controls the optical recording system 1. The host device 50 may be a personal computer. The host device 50 creates or prepares data for recording, and supplies a recording command for the data for recording to the RAID controller 40. Further, the host device 50 supplies a read command including a file name designated by a user or the like to the RAID controller 40, and acquires data of the corresponding file name from the RAID controller 40 as a response. *

[Operation of Optical Recording System 1] Next, control when recording is performed on the optical disk 11 in one or more disk drives 31 in the drive unit 30 of the optical recording system 1 will be described. *

A data recording command is given from the host device 50 to the controller 82 of one or more disk drives 31 in the drive unit 30 through the RAID controller 40. Since the operation of each disk drive 31 when receiving a recording command is the same, the operation of one disk drive 31 will be described. *

The controller 82 of the disk drive 31 controls the feed mechanism 80 so that the optical pickup 32 is moved to a position corresponding to the innermost circumference of the area in which no data is recorded in the recording area of the recording layer 113 of the optical disk 11, and The disk motor drive unit 79 is controlled to rotate the disk 11 at an appropriate speed in the CLV method or the CAV method. *

Further, the controller 82 sets the position of the first relay lens 36 of the optical pickup 32 in the optical axis direction so that the recording light from the objective lens 60 of the optical pickup 32 is focused on the target recording layer 113 of the optical disc 11. At the same time, the position of the second relay lens 66 of the optical pickup 32 in the optical axis direction is controlled so that the guide light from the objective lens 60 of the optical pickup 32 is focused on the guide layer 112 of the optical disc 11. *

The controller 82 of the disk drive 31 supplies the recording data transferred from the host device 50 through the RAID controller 40 to the data modulator 72. The data modulation unit 72 generates a recording signal by performing modulation of recording data, adding an error correction code, and the like, and supplies the recording signal to the first light source driving unit 73. The first light source driving unit 73 generates a driving pulse for the first light source 33 based on the recording signal and supplies it to the first light source 33. At the same time, the controller 82 outputs a control signal to the second light source driving unit 74 so as to drive the second light source 63. Thereby, recording of data on the recording layer 113 by the recording light from the optical pickup 32 is started. That is, data recording by the CLV method or the CAV method is started from the inner periphery to the outer periphery with respect to the target recording layer 113 of the optical disc 11. *

(Tracking control) Next, tracking control during data recording will be described. The tracking control is performed using guide tracks 121 provided on the guide layer 112 of the optical disc 11 with a track pitch of 0.32 μm. The tracking control unit 71 generates a tracking error signal based on the output of the second light receiving unit 69 by, for example, a PP (push-pull) method or a DPP (differential push-pull) method, and based on this tracking error signal Then, a tracking drive signal is supplied to the tracking actuator 70, and the objective lens 60 is moved in a direction perpendicular to the optical axis (disk radial direction) to perform tracking control. *

Next, the operations of the wobble reproduction unit 78 and the flag processing unit 83 that generate the timing for reversing the tracking servo polarity at the switching point between the land part and the groove part in this tracking control will be described.

The wobble reproduction unit 78 reproduces the wobble signal based on the output of the second light receiving unit 69. Since the wobble reproduction unit 78 has a function of discriminating the reproduced wobble signal into a data wobble signal and a flag wobble signal based on a frequency or the like, when the beam spot of the guide light is in the data area 123 of the guide track 121, The wobble signal is discriminated as a data wobble signal, physical address information is demodulated from the data wobble signal, and a recording clock is generated from the data wobble signal. *

When the beam spot of the guide light is in the polarity inversion flag region 122 of the guide track 121, the wobble reproduction unit 78 discriminates the wobble signal as a flag wobble signal and supplies the flag wobble signal to the flag processing unit 83. The flag processing unit 83 detects the polarity inversion flag region 122 based on the flag wobble signal supplied from the wobble reproduction unit 78, and generates the timing of the switching point between the land portion and the groove portion. At this timing, the tracking servo polarity Is supplied to the tracking control unit 71. Next, more specific configurations and operations of the wobble playback unit 78 and the flag processing unit 83 will be described. *

[Specific Example 1 of Wobble Reproduction Unit 78 and Flag Processing Unit 83] FIG. 8 is a block diagram showing a more specific configuration of the wobble reproduction unit 78 and the flag processing unit 83. *

The wobble reproduction unit 78 includes a wobble signal generation unit 90, a wobble discriminator 91, a wobble PLL 92, and a recording clock PLL 93. The flag processing unit 83 includes a flag wobble counter 94 and a clock counter 95. *

In the wobble reproduction unit 78, the wobble signal generation unit 90 generates a wobble signal using the signal from the second light receiving unit 69. The generated wobble signal is discriminated by the wobble discriminator 91 into a data wobble signal and a flag wobble signal based on, for example, the frequency and amplitude of the wobble signal. The data wobble signal is supplied to a wobble PLL (Phase-Locked Loop) 92, where a wobble clock which is a clock corresponding to the data wobble period is generated. The wobble clock is multiplied by the recording clock PLL 93 to generate a recording clock. The generated recording clock is supplied to the data modulation unit 72 and also to the clock counter 95 of the flag processing unit 83 and the like. *

On the other hand, the flag wobble signal discriminated by the wobble discriminator 91 is supplied to the flag wobble counter 94 in the flag processing unit 83. The flag wobble counter 94 counts the flag wobble signal supplied from the wobble discriminator 91. For example, when the flag wobble counter 94 determines that n flag wobble signals have been continuously input, the flag wobble counter 94 determines that the beam spot of the guide light is currently in the polarity inversion flag region 122 and counts it to the clock counter 95. A start signal is output. *

Here, as shown in FIG. 6, n or more flag wobbles are continuously provided from the start point of the polarity inversion flag region 122 in the recording direction. The distance from the position where n flag wobbles are completed to the switching point between the land portion and the groove portion can be expressed by the number x of recording clocks. Therefore, the clock counter 95 supplies a tracking servo polarity switching signal to the tracking controller 71 when the number of recording clocks supplied from the recording clock PLL 93 reaches x after starting the counting. *

Based on the tracking servo polarity switching signal, the tracking control unit 71 determines the polarity of the tracking drive signal, that is, the direction in which the objective lens 60 is moved, in the + direction (direction toward the outer periphery of the disk) and the − direction (in the disk). (Direction toward the lap). *

(Data recording to the area corresponding to the polarity reversal flag area 122 of the recording layer) In the disk drive 31 of the present embodiment, significant user data recording to the recording layer 113 corresponds to the data area 123 of the guide layer 112. This is performed only in the area, and recording of user data is stopped in the area corresponding to the polarity inversion flag area 122. That is, the user data is recorded on the recording layer 113 so that the logical addresses are continuous before and after the area corresponding to the polarity inversion flag area 122. However, if there is no pit string in the area corresponding to the polarity inversion flag area 122, an extra DC component is generated in the reproduction signal, which may adversely affect data demodulation processing. In such a case, for example, a pit string of dummy data obtained by repeating a 9-T mark and a space may be recorded in an area corresponding to the polarity inversion flag area 122 of the recording layer 113. A method for generating a logical address will be described later. *

More specifically, for example, when the flag wobble counter 94 in the flag processing unit 83 determines that n flag wobble signals have been continuously input, the beam spot of the current guide light is changed to the polarity inversion flag region 122. At the same time, a count start signal is output to the clock counter 95, and at the same time, a start point detection signal of the polarity inversion flag region 122 is supplied to the controller 82, and a tracking servo polarity switching signal is supplied to the tracking controller 71. The end point detection signal of the polarity reversal flag region 122 is supplied to the controller 82 at the timing of *

The controller 82 gives dummy data by repeating, for example, a 9-T mark and a space to the data modulation unit 72 after receiving the start point detection signal of the polarity inversion flag region 122 until receiving the end point detection signal. Control to output. As described above, the recording is continuously performed during the period from the reception of the start point detection signal of the polarity inversion flag region 122 to the reception of the end point detection signal, so that tracking during reproduction can be stabilized. it can. *

As described above, the tracking servo polarity can be switched at the switching point between the land portion and the groove portion with high accuracy in the order of the recording clock cycle. In the present embodiment, since the guide track 121 is continuously provided in the entire circumference, the tracking control is executed without interruption, and stable tracking control is possible even when the switching point between the land portion and the groove portion is sandwiched. It becomes. *

<Modification> In the above embodiment, a flag signal for generating the timing of the switching point between the land part and the groove part in the disk drive 31 is recorded in the polarity reversal flag area 122 of the guide track 121 by wobble. However, the present invention is not limited to this. *

For example, as shown in FIG. 9, a flag signal for causing the disc drive 31 to generate the timing of the switching point between the land portion and the groove portion is configured by a pit row in the polarity reversal flag region 122 of the guide track 121. Also good. *

In this case, the mark and space pattern constituting the pit row used in the polarity reversal flag region 122 may be any when the other data is not pre-written on the guide track 121 by the pit row by the 8-16 modulation method or the like. Such may be used. Alternatively, in the case where other data is pre-written on the guide track 121 with a pit row by, for example, the 8-16 modulation method, dummy data using a mark length that is not used in the 8-16 modulation method can be used. Good. *

As an example, in this modification, it is assumed that a pit string is recorded only in the polarity inversion flag area 122. In this case, the mark and space pattern constituting the pit row may be any pattern that allows the disk drive to detect the polarity reversal flag region 122 reliably and quickly. In the example of FIG. 9, for example, with m being an arbitrary value, a pit row pattern in which mT-length spaces and mT-length marks are alternately continued at least n times is prewritten from the tip of the polarity inversion flag region 122. ing. *

FIG. 10 shows a disc that employs a method of generating a timing for reversing the tracking servo polarity at the switching point between the land portion and the groove portion from the polarity reversal flag region 122 in which the flag signal is recorded in the pit row pattern as described above. It is a block diagram which shows the structure of drive 31A. *

In this disk drive 31A, the pit row flag processing unit 83A generates a signal obtained by fully adding the voltage signals obtained from the divided light receiving surfaces from the second light receiving unit 69, and equalization processing of the generated signal After the binarization, the polarity inversion flag region 122 is detected, the timing of the switching point between the land portion and the groove portion is generated, and the tracking servo polarity switching signal is generated at the generated timing by the tracking control unit 71 and the controller 82. To supply. *

Next, a specific configuration of the pit row flag processing unit 83A will be described. FIG. 11 is a block diagram showing a more specific configuration of the wobble playback unit 78A and the pit string flag processing unit 83A. *

The wobble reproduction unit 78A includes a wobble signal generation unit 90A, a wobble PLL 92A, and a recording clock PLL 93A. The pit string flag processing unit 83A includes an equalizer 96A, a pit string flag detecting unit 97A, a clock counter 95A, and the like. *

In the wobble reproduction unit 78A, the wobble signal generation unit 90A generates a wobble signal using the signal from the second light receiving unit 69. The generated wobble signal is supplied to the wobble PLL 92A, where a wobble clock which is a clock corresponding to the wobble cycle is generated. The wobble clock is multiplied by the recording clock PLL 93A to generate a recording clock. The generated recording clock is supplied to the data modulation unit 72 and is also supplied to the clock counter 95A in the pit string flag processing unit 83A. *

On the other hand, a signal from the second light receiving unit 69 (a signal obtained by fully adding the voltage signals obtained by the divided light receiving surfaces) is supplied to the equalizer 96A in the pit string flag processing unit 83A, where Are removed and then supplied to the pit row flag detector 97A. Based on the binary signal output from the equalizer 96A, the pit row flag detection unit 97A generates a predetermined pit row pattern in which mT length spaces and mT length marks are alternately repeated n times. It is determined as a flag signal. When the pit row flag detection unit 97A detects the pit row pattern of the flag signal, it determines that the beam spot of the guide light is currently in the polarity inversion flag region 122 and outputs a count start signal to the clock counter 95A. Note that m is a predetermined integer. *

Here, as shown in FIG. 9, the distance from the position where the pit string pattern, which is the flag signal, is completed to the switching point between the land portion and the groove portion can be expressed by the number x of recording clocks. Therefore, the clock counter 95A supplies a tracking servo polarity switching signal to the tracking control unit 71 when the number of recording clocks supplied from the recording clock PLL 93A reaches x after starting the counting. *

As described above, according to this modification, the tracking servo polarity can be switched at the switching point between the land portion and the groove portion with high accuracy in the order of the recording clock cycle. *

<Other Modifications> In the embodiment and the modification described above, the case where a guide track having a wobbling land / groove structure has been described. These examples are identical in that the recording clock for generating the tracking servo polarity switching timing is generated from the data wobble signal. *

However, the present invention is not limited to this. For example, in the case where physical address information is recorded in a pit row on a land / groove guide track, the pit row can generate a similar recording clock. The switching timing of the tracking servo polarity may be generated using a recording clock generated by using the recording clock.

(Regarding Logical Address Assigned to User Data of Recording Layer) FIG. 12 is a diagram showing the relationship between the physical address of the data area of the guide layer and the logical address assigned to the data area of each recording layer. 12, the solid line indicates the physical address of the data area of the guide layer, and the dotted line indicates the logical address assigned to the data areas of the four recording layers. The four recording layers are denoted as a recording layer L0, a recording layer L1, a recording layer L2, and a recording layer L3 in order from the one closest to the guide layer. Note that user data is recorded on the four recording layers in the order of L0, L1, L2, and L3, and user data is recorded on each recording layer from the inner periphery toward the outer periphery. *

Since the physical address space of the data area of the guide layer has only the capacity of the data area of one recording layer, it can be assigned only to the logical address space of the data area of one recording layer as it is. Therefore, in this embodiment, the logical addresses of the data areas of all the recording layers indicated by the dotted lines are obtained by calculation from the physical address of the guide layer and the recording layer information. *

Specifically, in this calculation, the maximum physical address (final physical address) in the guide layer is PSN_max, the recording layer information of the recording layer Lx is x (x = 0, 1, 2,...), And the recording layer Lx. LSN = (PSN_max × x) + PSN, where PSN is the physical address corresponding to the recording destination position in the data area, and LSN is the logical address given to the data unit recorded at the recording destination position in the data area of the recording layer Lx ... Performed by equation (1). *

FIG. 13 is a diagram showing specific allocation of logical addresses. For example, it is assumed that physical addresses from “1” to “100” are assigned to the guide layer from the inner peripheral side, the top physical address of the data area of the guide layer is “10”, and the last of the data area of the guide layer is The physical address is “90”. Note that the values of these physical addresses are only values determined for convenience of explanation. *

When the logical address LSN is calculated according to the equation (1), in the case of the data area of the recording layer L0 (x = 0), the calculation result of (100 × 0) + PSN becomes the logical address. Physical addresses “10” to “90” are assigned as logical addresses of the data area of the recording layer L0 as they are. Since the calculation result of (100 × 1) + PSN is a logical address in the data area of the recording layer L1 (x = 1), “110” to “190” are assigned as the logical address of the data area of the recording layer L1. . Since the calculation result of (100 × 2) + PSN is a logical address in the data area of the recording layer L2 (x = 2), “210” to “290” are assigned as the logical address of the data area of the recording layer L2. . Since the calculation result of (100 × 3) + PSN is a logical address in the data area of the recording layer L3 (x = 3), “310” to “390” are assigned as logical addresses of the data area of the recording layer L3. . *

When reading user data from the recording layer, the logical address (LSN) specified by the host device 50 is divided by the maximum physical address (PSN_MAX) of the guide layer. The quotient value obtained by this calculation is the recording layer information (x), and the remainder is the physical address (PSN). *

After the logical address is created as described above, the controller 82 creates an ID by merging the created sector information (Sector Information) and the logical address. Subsequently, the controller 82 adds the error detection code, user data, and error detection code of the ID to the ID to create a data frame. Further, the controller 82 scrambles the data frame, creates an ECC block, and interleaves, and supplies the result to the data modulator 72 as data for recording. *

The data modulation unit 72 modulates the recording data with a recording code such as an 8/16 conversion code and supplies the modulation signal to the first light source driving unit 73. The first light source drive unit 73 supplies drive pulses to the first light source 33 based on the modulation signal from the data modulation unit 72. As a result, the recording / reproducing light R 1 is emitted from the first light source 33, and user data is recorded in the data area of the recording layer of the optical disk 11.

DESCRIPTION OF SYMBOLS 1 ... Optical recording system 10 ... Storage unit 11 ... Optical disk 31 ... Disk drive 32 ... Optical pick-up 71 ... Tracking control part 78 ... Wobble reproduction part 79 ... Disc motor drive part 82 ... Controller 83 ... Flag processing part 90 ... Wobble signal generation part 91 ... Wobble discriminator 92 ... Wobble PLL 93 ... Recording clock PLL 94 ... Flag wobble counter 95 ... Clock counter 112 ... Guide layer 113 ... Recording layer 121 ... Guide track 122 ... Polarity reversal flag area 123 ... Data area

Claims

One or more recording layers, and a guide layer provided as a guide track in which the land portion and the groove portion are spirally continuous, and the guide track is switched between the land portion and the groove portion in the recording direction. A guide layer separation type optical recording medium, characterized in that a flag area in which a flag signal for causing the optical recording device to generate the timing of the switching point is provided immediately before the point.
The guide layer separation type optical recording medium according to claim 1, wherein the flag signal is recorded by wobbling the guide track.
The guide layer separation type optical recording medium according to claim 1, wherein the flag signal is recorded by a pit row.
One or more recording layers, and a guide layer provided as a guide track in which the land portion and the groove portion are spirally continuous, and the guide track is switched between the land portion and the groove portion in the recording direction. An optical recording apparatus for recording on a guide layer separation type optical recording medium provided with a flag area in which a flag signal for generating the timing of the switching point in the optical recording apparatus is generated immediately before the point, A drive unit for driving a guide layer separation type optical recording medium and a guide track of the guide layer of the driven optical recording medium are irradiated with laser light as guide light, and the return light of the guide light is converted into a received light signal. And an optical pickup having a guiding optical system that performs tracking control that generates a tracking error signal based on the received light signal and performs tracking control A light comprising: a control unit; and a flag processing unit that detects the flag signal based on the received light signal, generates the timing of the switching point, and sequentially reverses the polarity of the tracking control at the generated timing. Recording device.
The optical recording apparatus according to claim 4, further comprising a clock generation unit that generates a reference clock based on the light reception signal, wherein the flag processing unit is configured to generate the flag signal based on the light reception signal. An optical recording apparatus that counts the number of clocks after detecting the signal and generates the timing when the count value reaches a predetermined value as the timing of the switching point.
6. The optical recording apparatus according to claim 5, wherein the flag signal is recorded as a predetermined wobble of the guide track, and the flag processing unit is recorded as the predetermined wobble based on the light reception signal. An optical recording device that detects flag signals.
6. The optical recording apparatus according to claim 5, wherein the flag signal is recorded as a predetermined pit row on the guide track, and the flag processing unit is recorded as the predetermined pit row based on the light reception signal. An optical recording device that detects the flag signal.
8. The optical recording apparatus according to claim 4, wherein the recording layer is a period from when the flag signal is detected by the flag processing unit to when the timing of the switching point is generated. An optical recording apparatus further comprising a control unit that performs control so as to stop recording.
8. The optical recording apparatus according to claim 4, wherein the recording layer is a period from when the flag signal is detected by the flag processing unit to when the timing of the switching point is generated. An optical recording apparatus further comprising a control unit that performs control so as to record dummy data.