WO2014050398A1

WO2014050398A1 - Optical recording device, optical recording method, and multilayer optical disk

Info

Publication number: WO2014050398A1
Application number: PCT/JP2013/072657
Authority: WO
Inventors: 賢一下舞
Original assignee: 太陽誘電株式会社
Priority date: 2012-09-28
Filing date: 2013-08-26
Publication date: 2014-04-03
Also published as: JP2014071928A; TW201428740A

Abstract

[Problem] The present invention enables excellent recording with respect to a plurality of recording layers of a multilayer optical disk. [Solution] A controller (83B) of a disk drive causes the position of a focus of a light beam to move in such a range that the light beam passes through at least a plurality of recording layers; estimates positions of the recording layers based on a waveform of a focus error signal generated in response to this movement by a focus error generation section; assigns pieces of temporary layer information to the estimated positions of the recording layers, respectively; turns on focus servo in a state in which the focus is on the estimated position of the recording layer selected as a recording destination where user data are to be recorded, by using temporary layer information; reads layer information from a lead-in area of a recording layer where the focus servo is drawn in; compares this read layer information and the temporary layer information used for selection of the recording layer as a recording destination where user data are to be recorded; and, if these pieces of information coincide with each other, recognizes that the recording layer where the focus servo is drawn in as the recording layer selected as the recording destination of the user data.

Description

Optical recording apparatus, optical recording method, and multilayer optical disk

The present invention relates to an optical recording apparatus, an optical recording method, and a multilayer optical disc that perform recording on a multilayer optical disc having a plurality of recording layers.

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 using light (guide light) having a wavelength (red) of 650 nm to 680 nm on a guide track layer provided with a guide track having a groove structure, and one of the plurality of recording layers is recorded. In addition, there is an optical disk drive that performs recording using light (recording / reproducing light) having a wavelength (blue) of 390 nm to 420 nm. *

In such an optical disc drive, one of the problems is to accurately focus the recording / reproducing light on the target recording layer among the plurality of recording layers. The following techniques are known for such problems. *

In this known optical disc drive, since the distance between the guide layer of the multilayer optical disc and the target recording layer is known, in the state where the above distance is set to the focal position of the guide light and the focal position of the recording / reproducing light, The objective lens is moved in the optical axis direction to irradiate the multilayer optical disc with recording / reproducing light and guide light, respectively. This optical disk drive is obtained from the waveform of the focus error signal based on the return light of the recording / reproducing light from each recording layer and the waveform of the focus error signal based on the return light of the guide light from the guide layer obtained during this time. The timing when the recording layer is focused is determined. That is, this optical disc drive performs recording / reproduction from the recording layer at the timing when the S-curve signal waveform indicating that the guide layer is focused in the focus error signal based on the return light of the guide light from the guide layer is generated. The focus error signal based on the return light of the light is gated, and the focus servo is pulled in based on the gated focus error signal. As a result, it is possible to solve the problem that the focus servo is pulled into a recording layer other than the intended one.

JP 2010-40093 A

However, in the method of determining the target recording layer based on the waveform of the focus error signal, it is not possible to logically check whether the determined recording layer is actually the target recording layer. For this reason, for example, when the distance between the guide layer and the target recording layer is actually deviated from a known value, the focus servo may be drawn into a recording layer other than the target recording layer due to the error. There is sex. If the focus servo is drawn into a recording layer other than the target recording layer, the recording layer is regarded as the target recording layer as it is, and recording is performed, which causes various troubles. *

In view of the circumstances as described above, an object of the present invention is to enable good recording on a plurality of recording layers of a multilayer optical disc.

In order to achieve the above object, an optical recording apparatus according to an aspect of the present invention includes a plurality of recording layers capable of recording information, and a guide layer provided with a guide track for tracking. Each of the recording layers is an optical recording apparatus for recording on a multilayer optical disc having a layer information recording area in which layer information for identifying the recording layer of the recording layer is recorded, the light source emitting a light beam, and the light beam An objective lens that focuses the light onto the multilayer optical disc, a light receiving unit that receives the light beam reflected by the multilayer optical disc, and outputs an electrical signal, a focus error generation unit that generates a focus error signal from the output of the light receiving unit, The focus position of the light beam is moved within a range that allows at least the plurality of recording layers to pass, and the focus error generation unit generates the movement along with the movement. The position of the plurality of recording layers is estimated on the basis of the waveform of the focus error signal, and provisional layer information is assigned to each of the estimated positions of the plurality of recording layers, and the user uses the provisional layer information. The focus servo is turned on from a state in which the estimated position of the recording layer selected as the data recording destination is focused, and the layer information is read from the layer information recording area of the recording layer to which the focus servo is drawn, The read layer information is compared with the provisional layer information used to select the recording layer as the recording destination of the user data, and if they match, the recording layer into which the focus servo is drawn is determined as the user data. And a control unit that determines the recording layer selected as the data recording destination. *

In the optical recording apparatus according to the present invention, the layer information read from the layer information recording area of the recording layer is compared with the temporary layer information assigned to the position of the recording layer selected as the recording destination of the user data. It is possible to logically check whether the recording layer into which the focus servo is drawn is the recording layer selected as the user data recording destination. *

An optical recording method according to another aspect of the present invention includes a plurality of recording layers capable of recording information and a guide layer provided with a guide track for tracking, and each of the plurality of recording layers is itself An optical recording method for recording on a multi-layer optical disc having a layer information recording area in which management information including layer information for identifying the recording layer is recorded, wherein the focus position of the light beam is at least the plurality of recording layers The position of the plurality of recording layers is estimated based on the waveform of the focusing error signal generated along with the movement, and a temporary layer is placed at the estimated position of the plurality of recording layers. Each of the information is assigned and the focus servo is turned on from the state where the estimated position of the recording layer selected as the user data recording destination is focused using the temporary layer information. The layer information is read from the layer information recording area of the recording layer to which the focus servo is drawn, and the provisional layer used for selecting the read layer information and the recording layer as the recording destination of the user data is used. The layer information is compared, and if they match, the recording layer into which the focus servo is drawn is determined as the recording layer selected as the recording destination of the user data. *

A multilayer optical disc according to another aspect of the present invention has a plurality of recording layers capable of recording information, and a guide layer provided with a guide track for tracking, and each of the plurality of recording layers has its own recording layer. It has a lead-in area in which management information including layer information for identifying a recording layer is recorded, and the lead-in area is arranged with a position shifted between adjacent recording layers. . This enables the disk drive to read the layer information of the recording layer from the recording layer in which the focus is drawn. In addition, since the lead-in area of each recording layer is arranged so as to be shifted from each other between the adjacent recording layers, generation of interlayer crosstalk during access of the lead-in area can be suppressed, and layer information is included. Management information can be read stably by the optical recording apparatus. *

In the multilayer optical disc, management information including layer information may be recorded in advance in the lead-in area. *

A multilayer optical disc according to another aspect of the present invention has a plurality of recording layers capable of recording information and a guide layer provided with a guide track for tracking, and each of the plurality of recording layers has its own recording layer. Layer information for identifying a recording layer has a BCA (Burst_Cutting_Area) recorded in advance, and the BCAs of the plurality of recording layers are arranged at different disk radial positions. Thereby, in the disk drive, the layer information of the recording layer can be read from the BCA of the recording layer in which the focus is drawn. Further, since the BCAs of the respective recording layers are arranged at different disk radial positions, it is possible to suppress the occurrence of a reading error due to interference between the BCAs of different recording layers, and the optical recording apparatus can stably store the layer information. Can be read. *

A disc identifier for identifying a multilayer optical disc may be recorded in advance in the BCA.

As described above, according to the present invention, it is possible to perform good recording on a plurality of recording layers of a multilayer optical disc.

1 is a diagram showing an optical recording system according to an embodiment of the present invention. It is a figure which shows the accommodation form of the disc cartridge in the optical recording system of FIG. 1, and the several multilayer optical disk in this. It is a figure which shows the structure of the disk cartridge in the optical recording system of FIG. 1, a multilayer optical disk, and a drive unit. It is sectional drawing which shows the structure of a multilayer optical disk. FIG. 5 is a diagram illustrating a configuration of a region divided by radial positions of a guide layer and a recording layer in the multilayer optical disc of FIG. FIG. 6 is a diagram showing a physical format showing a relationship between recording positions of management information of each recording layer in the recording layer lead-in area of FIG. 5. FIG. 6 is a diagram showing a modification of the physical format showing the relationship between the recording positions of the management information of each recording layer in the recording layer lead-in area of FIG. 5. It is a figure which shows the structure of the disk drive in the optical recording system of FIG. FIG. 9 is a diagram illustrating an example of a focus error signal obtained during the swing period of the optical pickup and a binarization signal generated by the binarization unit from the focus error signal in the disk drive of FIG. 8. FIG. 9 is a flowchart of an operation for confirming the alignment between the recording layer selected as the user data recording destination and the recording layer into which the focus servo is actually drawn based on the layer information in the disk drive of FIG. 8. It is a whole top view of the multilayer optical disc of the 2nd embodiment concerning the present invention. FIG. 12 is a detailed plan view of a BCA portion of the multilayer optical disc in FIG. 11. FIG. 13 is a cross-sectional view taken along the line AA of the multilayer optical disc of FIG. It is a block diagram which shows the structure of the disk drive of 2nd Embodiment which concerns on this invention. It is a flowchart which shows the operation | movement of the confirmation of the recording layer by the disc drive of 2nd Embodiment. It is a block diagram which shows the structure of the disk drive of a modification. It is a figure which shows the waveform of a BCA reproduction signal.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
<First Embodiment>
FIG. 1 is a diagram showing the overall configuration of an optical recording system. The optical recording system 1 includes a disk cartridge 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.

[Disc Cartridge 10] The disc cartridge 10 is a unit in which a plurality of multilayer optical discs 11 which are multilayer optical recording media are individually detachably accommodated. *

FIG. 2 is a view showing a storage form of the disk cartridge 10 and a plurality of multilayer optical disks 11 therein. As the accommodation form of the plurality of multilayer optical discs 11 in the disc cartridge 10, flat stacking, vertical alignment, and the like are assumed. In any case, it is preferable that a certain gap is provided between adjacent multilayer optical discs 11 so that the multilayer optical disc 11 can be smoothly inserted into and removed from the disc cartridge 10. The shape of the disk cartridge 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 multilayer optical disk 11. In the example of FIG. 2, a rectangular parallelepiped disk cartridge 10 in which a plurality of multilayer optical disks 11 are accommodated in a flat stack is used. *

FIG. 3 is a diagram showing the configuration of the disk cartridge 10, the multilayer optical disk 11, and the drive unit 30. At least one side surface of the disc cartridge 10 is provided with an opening 110 for inserting and removing the multilayer optical disc 11 and a door (not shown) for opening and closing the opening 110. The door is opened and closed in conjunction with the operation of loading / unloading the multilayer optical disk 11 from / to the disk cartridge 10 by the disk transport mechanism 20, and is closed at other times. The plurality of multilayer optical disks 11 accommodated in the disk cartridge 10 are taken out by the disk transport mechanism 20 and selectively transported (loaded) to the plurality of disk drives 31 in the drive unit 30. *

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

[Multilayer Optical Disc 11] The multilayer optical disc 11 accommodated in the disc cartridge 10 is assumed to be a so-called guide layer separation type multilayer optical disc in which the guide layer and the recording layer are separated into separate layers. . *

FIG. 4 is a cross-sectional view showing a configuration of a multilayer optical disc 11 that is a guide layer separation type multilayer optical disc. The multilayer optical disk 11 includes a guide layer 112 and a plurality of recording layers 113. In the example of the multilayer optical disk 11 in FIG. 9, 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. Each recording layer 113 is distinguished from the opposite side of the laser beam incident side (guide layer side) as “recording layer L0”, “recording layer L1”, “recording layer L2”, and “recording layer L3”. To do. *

A guide track 121 having a land / groove structure is spirally or concentrically provided on the surface of the guide layer 112 facing the recording layer 113. In the guide track 121, physical address information is formed by wobbling or pit rows on the side wall surface. 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 the optical recording system 1 of the present embodiment, for example, a push-pull method (PP: Push-Pull), a differential push-pull method (DPP: Differential-Push-Pull), 3 beams in each of the land and groove of the guide track 121. Tracking control is performed by law. By performing tracking control in each of the land and groove of the guide track 121, information can be recorded on the recording layer 113 at a track pitch of 0.32 μm. *

The recording layer 113 is a layer on which information is recorded at a track pitch (0.32 μm) corresponding to blue laser light used for recording / reproducing of a Blu-ray Disc (registered trademark), for example. Hereinafter, this blue laser light is 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 multilayer optical disc 11 is irradiated with the recording light, the reflectance of the area irradiated with the recording light is changed, and the area where the reflectance is changed is formed as a recording mark. Information is recorded in layer 113. *

The tracking control and the acquisition of the physical address and the reference clock at the time of recording information on the recording layer 113 are performed by using the guide track 121 of the guide layer 112. Therefore, the recording layer 113 has a land / groove structure guide track. 121 is not necessary. Therefore, the surface of the recording layer 113 may be flat. *

FIG. 5 is a diagram showing a configuration of regions divided by radial positions of the guide layer 112 and the recording layer 113 in the multilayer optical disc 11. The guide layer 112 and the recording layer 113 are divided into the lead-in area, the data area, and the lead-out area in common from the inner circumference side depending on the position in the radial direction. *

In the lead-in area of the guide layer 112, management information unique to the multilayer optical disk 11 is recorded in advance by wobbling of guide tracks or pit rows provided in lands and grooves. The management information unique to the multilayer optical disc 11 includes, for example, recommended information such as the number of recording layers, recording method, recording linear velocity, laser power and laser drive pulse waveform during recording / reproduction, position information of the data area, position of the OPC area Contains information. The OPC area is provided, for example, on the inner peripheral side of the lead-in area. Also, in the lead-in area of the guide layer 112, the position information (disk radius position) of each recording layer 113 is recorded in advance by wobbling of the guide track or pit rows provided in the land and groove. Has been. *

In the data area of the guide layer 112, physical address information assigned to the data area is recorded in advance by wobbling of the guide track 121 or prepit rows provided in lands and grooves. *

In the lead-out area of the guide layer 112, the same information as the information recorded in the lead-in area may be recorded in advance by wobbling of the guide track 121 or a prepit row provided in the land and groove. Good. *

The lead-in area of the recording layer 113 (hereinafter referred to as “recording layer lead-in area”) is an area where management information used for recording / reproduction of the recording layer 113 is recorded by a recording mark. Management information used for recording / reproduction of the recording layer 113 includes layer information such as a layer number assigned to which recording layer 113 is assigned, replacement management information regarding replacement processing of a defective area, OPC processing (calibration processing). The recording condition data such as the optimum laser power at the time of recording determined by (1) is included. Among these, at least the layer information is, for example, information recorded with a recording mark on each recording layer 113 before the multilayer optical disc 11 is actually used for data recording by the user. Such layer information may be recorded in advance on each recording layer when, for example, a multilayer optical disc is manufactured. If recording is performed when a multilayer optical disc is manufactured, layer information can be recorded for each manufacturing lot, so that layer information can be recorded more accurately without being subject to fluctuations in lot-to-lot variations. *

FIG. 6 is a diagram showing a physical format showing the relationship between the recording positions of the management information of each recording layer 113 in the recording layer lead-in area. As shown in the figure, in the recording layer lead-in area, the management information of each recording layer 113 is recorded so that the positions are shifted from each other at least between the adjacent recording layers. Here, “the position shifts” means “the positions do not overlap”. More specifically, the lead-in area of the recording layer 113 is divided into at least as many child areas as the number of recording layers depending on the position, and these child areas are assigned to different recording layers as follows, for example. *

Here, the child areas are designated as “child area E0”, “child area E1”, “child area E2”, and “child area E3” from the inner peripheral side of the disc. When the four recording layers 113 are designated as “recording layer L0”, “recording layer L1”, “recording layer L2”, and “recording layer L3” from the one closest to the guide layer 112, the child area E0 is subordinate to the recording layer L0. E1 is assigned to the recording layer L1, the child area E2 is assigned to the recording layer L2, and the child area E3 is assigned to the recording layer L3. *

As described above, by assigning separate recording layers to a plurality of child areas that divide the recording layer lead-in area, the management information of each recording layer 113 is at least adjacent in the recording layer lead-in area. The recording layers are recorded with their positions shifted from each other. *

In addition, since the management information of each recording layer 113 should just be recorded so that a position may mutually shift between at least adjacent recording layers, you may employ | adopt the following arrangement | positioning. *

For example, as shown in FIG. 7, the child area of the recording layer L0 and the child area of the recording layer L2 are allocated to the same disk radius position (position E0) in the lead-in area, and the child area and the recording layer of the recording layer L1. The child area of L3 may be assigned to another disk radius position (position E1) in the lead-in area. *

By assigning a plurality of recording layer child areas to the same disk radial position in the lead-in area in this way, the size of the required lead-in area can be further reduced, and the recording capacity for each recording layer can be increased. I can plan. *

As described above, in the recording layer lead-in area, the management information of each recording layer 113 is recorded at a position shifted between at least adjacent recording layers for the following reason. . *

When information is read from an arbitrary recording layer of the multilayer optical disc 11, stray light reflected by a recording layer other than the recording layer to be read becomes noise called interlayer crosstalk and is mixed into return light from the recording layer to be read, It is known to adversely affect tracking control and recording / reproducing user data. Here, the occurrence of interlayer crosstalk is actually caused by factors that cause reflectance fluctuations such as recording marks of recording layers other than the recording layer to be read. For this reason, the management information of each recording layer 113 is recorded by shifting the position between at least adjacent recording layers, thereby suppressing the occurrence of interlayer crosstalk. *

[Disc Conveying Mechanism 20] The disc conveying mechanism 20 takes out the target multilayer optical disk 11 from the disk cartridge 10 and loads it into the disk drive 31 in the drive unit 30, or conversely discharges the multilayer optical disk 11 ejected from the disk drive 31 into a disk This is a mechanism for returning to the cartridge 10. *

The disk transport mechanism 20 operates independently so that, for example, a plurality of multilayer optical disks 11 can be taken out simultaneously or sequentially from the disk cartridge 10 and can be separately loaded into the plurality of disk drives 31 in the drive unit 30. A plurality of possible transport mechanisms may be provided. *

[Drive Unit 30] A plurality of disk drives 31 are mounted on the drive unit 30. In the example of FIG. 5, five disk drives 31 are mounted. In the example of FIG. 5, five disk drives 31 are mounted. The number of multilayer optical disks 11 accommodated in the disk cartridge 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. 8 is a diagram showing a configuration of the disk drive 31 that is an optical recording apparatus. The disk drive 31 includes an optical pickup 32. The optical pickup 32 includes a recording / reproducing optical system corresponding to the recording / reproducing light and a guide optical system corresponding to the guide light. *

The recording / reproducing 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 plate. 39, an objective lens 60, a first light receiving lens 61, a first light receiving portion 62, and the like. Here, the combining prism 38, the quarter wavelength plate 39, and the objective lens 60 belong to both the recording / reproducing optical system and a guide optical system described later. *

The first light source 33 includes a laser diode that emits blue laser light 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 makes 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 a guide optical system, which will be described later, coincide with each other. And is incident on the objective lens 60 through the quarter-wave plate 39. The incident recording / reproducing light is collected by the objective lens 60 so as to be focused on the target recording layer 113 of the multilayer optical disc 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. *

For example, the first light receiving unit 62 includes 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 divided light receiving surface. To do. *

The guide 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 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 that is red laser light. 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 is combined by the combining prism 38 so that the optical axis coincides with the recording / reproducing light R1 incident from the second collimator lens 37 of the recording / reproducing optical system. Then, the light enters the objective lens 60 through the quarter-wave plate 39. The incident guide light R <b> 2 is collected by the objective lens 60 so as to be focused on the guide layer 112 of the multilayer 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 constituted by, for example, a light receiving element whose light receiving surface is divided into four in the disk radial direction and the tangential direction. The second light receiving unit 69 outputs a voltage signal corresponding to the amount of received light for each divided light receiving surface. *

The optical pickup 32 is provided with a tracking actuator 70 and a focus actuator 79. The tracking actuator 70 moves the objective lens 60 in the disk radial direction that is perpendicular to the optical axis under the control of the tracking control unit 71. The focus actuator 79 moves the objective lens 60 in the optical axis direction under the control of the focus control unit 77. *

Further, the optical pickup 32 guides the guide light R2 and the first relay lens actuator 80 that moves the first relay lens 36 in the optical axis direction in order to switch the recording layer 113 irradiated with the recording / reproducing light. In order to focus on the layer 112, a second relay lens actuator 81 that moves the second relay lens 66 in the optical axis direction is provided. *

Also. Although not shown, the optical pickup 32 is also provided with a tilt actuator that adjusts the inclination of the objective lens 60 in the radial direction and the tangential direction with respect to the recording surface of the multilayer optical disc 11. The above is the description of the optical pickup 32. *

In addition to the optical pickup 32, the disk drive 31 includes a tracking control unit 71, a data modulation unit 72, a first light source drive unit 73, a second light source drive unit 74, an equalizer 75, a data reproduction unit 76, a focus A control unit 77, a binarization unit 78, a tracking error generation unit 82, a controller 83, a first relay control unit 84, a second relay control unit 85, and a focus error generation unit 86 are provided. In addition, the disk drive 31 includes a disk motor driving unit that drives the disk motor 91, a feed mechanism that sends the optical pickup 32 in the radial direction of the multilayer optical disk 11, and a pickup vertical feed mechanism that sends the optical pickup 32 in the optical axis direction of the objective lens 60. Etc. These illustrations are omitted. *

The data modulator 72 modulates the recording data supplied from the controller 83 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 an equalization process such as PRML (Partial Response Maximum Likelihood) on the reproduction RF signal from the first light receiving unit 62 to generate a binary signal. *

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 83. *

The tracking error generation unit 82 generates a tracking error signal based on the output of the second light receiving unit 69 by, for example, a push-pull method, a differential push-pull method, a three-beam method, or the like. *

The tracking controller 71 performs tracking control by controlling the tracking actuator 70 based on the tracking error signal to move the objective lens 60 in a direction perpendicular to the optical axis. *

The focus error generation unit 86 generates a focus error signal based on, for example, the astigmatism method based on the output of the first light receiving unit 62. *

The focus control unit 77 performs focus control by controlling the focus actuator 79 and moving the objective lens 60 in the optical axis direction based on the focus error signal. *

The binarization unit 78 binarizes the focus error signal generated by the focus error generation unit 86 during the swing of the optical pickup 32 at a predetermined slice level, and supplies the binarization unit 78 to the controller 83 as S-curve information of the focus error signal. *

The first relay control unit 84 controls the first relay lens actuator 80 so as to switch the recording layer to be recorded. *

The second relay control unit 85 controls the second relay lens actuator 81 so that the guide light R2 is focused on the guide layer 112. *

The controller 83 includes a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), and the like. The controller 83 controls the entire disk drive 31 based on a program loaded in the main memory area allocated to the RAM (corresponding to a “control unit” in the claims). *

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 multilayer 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 83 of each disk drive 31 to which a recording or reproduction instruction is given from the RAID controller 40 performs control for recording or reproducing data on the multilayer 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. *

As illustrated in FIG. 3, the host device 50 includes a CPU 51, a memory 52, a drive I / F 53, a disk transport mechanism I / F 54, and a system bus 56. *

The CPU 51 performs arithmetic processing for executing a program stored in the memory 52 and controls exchange of information with each unit through the system bus 56. The memory 52 is a main memory in which programs to be executed by the CPU 51 and calculation results are stored. *

The drive I / F 53 is an interface for communicating with the plurality of disk drives 31 through the RAID controller 40. *

The disk transport mechanism I / F 54 is an interface for communicating with the disk transport mechanism 20. [Operation of Disk Drive 31] Next, typical operations in the disk drive 31 according to the present embodiment are as follows. Recording of layer information 2. Description will be made in the order of confirmation of the recording layer using the layer information. *

(1. Recording of layer information) The procedure for recording layer information on the multilayer optical disc 11 is, for example, as follows. In the disk drive 31, it is assumed that the push-pull method is used for tracking control and the astigmatism method is used for focus control. *

1. The controller 83 of the disk drive 31 controls a feed mechanism (not shown) to move the optical pickup 32 to a predetermined radial position. The predetermined radial position is, for example, a radial position corresponding to the head of the lead-in area of the guide layer. At this position, the controller 83 adjusts the initial focus offset with respect to the guide layer and the tilt adjustment of the objective lens 60 as follows. *

2. That is, the controller 83 controls the second light source driving unit 74 to turn on the second light source 63. Thus, the guide light R2 is irradiated from the objective lens 60 of the optical pickup 32 to the guide layer 112 of the multilayer optical disc 11 through the guide optical system. The return light from the guide layer 112 of the multilayer optical disc 11 is received by the second light receiving unit 69, so that a voltage signal corresponding to the received light intensity is output from each divided region of the second light receiving unit 69.

3. Subsequently, the controller 83 drives the second relay lens actuator 81 through the second relay control unit 85 to move the second relay lens 66 to the initial position in the optical axis direction. Here, the initial position of the second relay lens 66 in the optical axis direction is a position determined in advance so that the guide light R <b> 2 from the objective lens 60 is focused on the guide layer 112. The controller 83 maximizes the amplitude of the tracking error signal (push-pull signal) generated by the tracking error generator 82 based on the voltage signal corresponding to the received light intensity from each divided region of the second light receiver 69. Thus, the focus offset with respect to the guide layer 112 is adjusted. *

4). Then, the controller 83 drives a tilt actuator (not shown) in the optical pickup 32 to change the inclination of the objective lens 60 in the radial direction and the tangential direction with respect to the recording surface of the multilayer optical disc 11, and the amplitude of the tracking error signal. The tilt adjustment in each direction is performed so that becomes maximum. Thus, the first focus offset adjustment with respect to the guide layer and the tilt adjustment of the objective lens 60 are completed. *

5. Next, the controller 83 supplies a control command to the first light source driving unit 73 so as to emit a laser beam having a power set for searching the recording layer, such as a reproducing power. As a result, the first light source 33 emits laser light having the power set for searching the recording layer, and irradiates the multilayer optical disc 11 through the recording / reproducing optical system. The return light from the multilayer optical disk 11 is received by the first light receiving unit 62 in the optical pickup 32, and a voltage signal corresponding to the received light intensity is output from each divided region of the first light receiving unit 62. *

6). Subsequently, the controller 83 controls a pickup vertical feed mechanism (not shown) so that the focus position of the recording layer search laser light passes through at least all the recording layers 113 of the multilayer optical disc 11 through the recording / reproducing optical system. The optical pickup 32 is moved (swinged) several times at a constant speed in the optical axis direction of the objective lens 60. At this time, the controller 83 changes the position of the first collimator lens 34 every swing in order to probabilistically try to correct the spherical aberration. *

FIG. 9 is a diagram illustrating an example of a focus error signal obtained during the swing period of the optical pickup 32 and a binarized signal generated by the binarization unit 78 from the focus error signal. Thus, every time the focal point of the laser beam passes through the swing period of the optical pickup 32, the protective layer of the multilayer optical disc 11, the recording layer L3, the recording layer L2, the recording layer L1, the recording layer L0, and the interlayer portion of the guide layer. The focus error signal generated by the focus error generator 86 changes to an S shape. Since the waveform of the S-shaped voltage includes a spherical aberration component caused by the layer spacing of the multilayer optical disc 11, the controller 83 adjusts the position of the first collimator lens 34 every swing, and The S-shaped voltage at the position of the first collimator lens 34 where the amplitude of the S-shaped voltage is maximum is determined as the S-shaped voltage in a state where the spherical aberration is corrected. *

7). The controller 83 obtains, as the S-curve information of the focus error signal, the result of binarizing the S-shaped voltage with the spherical aberration corrected at the predetermined slice level by the binarizing unit 78. *

Next, the controller 83 records layer information on each recording layer as follows, for example. Note that the recording order of layer information for each recording layer is assumed to be L0, L1, L2, and L3. *

9. First, in order to record layer information on the recording layer L0, the controller 83 moves the optical pickup 32 from a predetermined initial position to a position where the binarized signal becomes the “H” level for the fifth time. Control the focus servo to be pulled in at the position. As a result, the focus servo is drawn into the recording layer L0. *

10. After the focus servo is drawn into the recording layer L0, the controller 83 detects the light detection signal output from each divided region of the first light receiving unit 62 for the return light from the unrecorded region of the recording layer L0. The focus offset for the recording layer L0 is adjusted so that the sum signal is maximized. *

11. Subsequently, the controller 83 adjusts the focus offset with respect to the guide layer 112 again so that the amplitude of the tracking error signal is maximized. *

12 Subsequently, the controller 83 performs control so as to draw tracking servo into the guide track 121 of the guide layer 112. At this time, the controller 83 adjusts the tracking offset based on the waveform of the tracking error signal. For example, an intermediate potential between a maximum value and a minimum value in the waveform of the tracking error signal is used as an offset value, and the tracking error signal is adjusted with this offset value. *

Thereafter, the controller 83 performs control so as to record the layer information on the recording layer L0. When recording layer information, for example, as shown in FIG. 6, the controller 83 is assigned in advance to the recording layer L0 among the plurality of child areas E0 to E3 that divide the recording layer lead-in area. Control is performed so that the layer information is recorded in the child area E0. More specifically, information on the disk radius positions of the small areas E0 to E3 allocated to the respective recording layers is recorded in advance in the lead-in area of the guide layer. The controller 83 reads the information on the disk radial position of each of the small areas E0 to E3 from the lead-in area of the guide layer, identifies the child area for each recording layer based on this information, and stores the layer information here. Control to record. *

Subsequently, in order to record layer information on the next recording layer L1, the controller 83 moves the optical pickup 32 from a predetermined initial position to a position where the binarized signal becomes the “H” level for the fourth time. The focus servo is pulled in at this position. As a result, the focus servo is drawn into the recording layer L1, and thereafter, the same processing until the layer information is recorded on the recording layer L1 is performed. The processes until the layer information is recorded on the recording layer L2 and the recording layer L3 are repeated in the same procedure. *

The above layer information recording operation is merely an example, and other methods may be employed as long as management information can be recorded in the correct arrangement on each recording layer of the multilayer optical disc 11. *

(2. Confirmation of recording layer using layer information) In the disk drive 31 of this embodiment, before recording user data on the multilayer optical disk 11, confirmation of how many layers each recording layer is. For example, confirmation of the alignment between the recording layer selected as the user data recording destination and the recording layer into which the focus servo is actually drawn is performed. Next, this operation will be described with reference to the flowchart of FIG. *

This operation is started when, for example, the multilayer optical disc 11 on which layer information is recorded is loaded into the disc drive 31. *

The controller 83 of the disk drive 31 supplies a control command to the first light source driving unit 73 so that the first light source 33 emits a laser beam having a power set for searching the recording layer such as a reproduction power. To do. Subsequently, the controller 83 moves the focus position of the laser beam for searching the recording layer within a range in which at least all of the recording layers of the multilayer optical disc 11 are passed while the optical pickup 32 is placed at a predetermined initial position. In this manner, the pickup vertical feed mechanism (not shown) is controlled to move (swing) the optical pickup 32 a plurality of times in the direction of the optical axis of the objective lens 60 at a constant speed. At this time, the controller 83 changes the position of the first collimator lens 34 every swing in order to probabilistically try to correct the spherical aberration (step S101). *

The controller 83 determines the S-shaped voltage at the position of the first collimator lens 34 where the amplitude of the S-shaped voltage of the target recording layer is the maximum among the focus error signals (S-shaped voltage) obtained for each swing. Is obtained as S-curve information of the focus error signal, and the result obtained by binarizing the S-curve voltage at a predetermined slice level by the binarization unit 78 is obtained as the S-curve information of the focus error signal. (Step S102). *

The controller 83 estimates the position of each recording layer in the swing range of the optical pickup 32 based on the acquired S-curve information of the focus error signal, and provisional layer information is added to each estimated recording layer position. And the correlation information is stored in a memory in the controller 83. Here, the position of each recording layer is expressed by the amount of movement of the optical pickup 32 from the initial position, for example. The provisional layer information is allocated according to the same allocation rule as the layer information actually recorded in the lead-in area so that the layer information can be compared with the layer information actually recorded in the lead-in area of each recording layer ( Step S103). *

Thereafter, a recording layer as a recording destination of user data is selected using temporary layer information. For example, it is assumed that the recording layer L1 is selected as the user data recording destination based on the provisional layer information. The controller 83 reads the position information of the recording layer L1 corresponding to the provisional layer information from the memory, and controls the optical pickup lifting / lowering mechanism (not shown) based on this information to move the optical pickup 32 from the initial position in the optical axis direction. Move (step S104). *

Thereafter, the controller 83 sets the feed mechanism so as to move the optical pickup 32 in the disc radial direction to a position where the layer information can be read from the lead-in area in the recording layer L1 selected as the user data recording destination. Control is performed (step S105). More specifically, in order to perform this control, the controller 83 reads in advance the position information (disk radius position) of the lead-in area of each recording layer from the lead-in area of the guide layer and temporarily stores it in the memory in the controller 83. It is necessary to store in association with the layer information. The controller 83 acquires the position information of the lead-in area associated with the temporary layer information of the recording layer L1 selected as the user data recording destination from the memory, and based on this, the lead-in area in the recording layer L1 is read. The feed mechanism is controlled so that the optical pickup 32 is moved in the disk radial direction to a position where the layer information can be read from the area. *

Thereafter, the controller 83 supplies a control command to the focus control unit 77 so as to start the focus servo pull-in (step S106). As a result, the laser beam is focused on the recording layer that is closest to the focus position of the laser beam for searching the recording layer. At this time, the recording layer is designated as the recording destination. Whether it is L1 is uncertain. *

The controller 83 performs control so as to read layer information from the lead-in area of the focused recording layer (step S107). *

When the controller 83 succeeds in reading the layer information from the lead-in area of the focused recording layer, the read layer information matches the temporary layer information used for selecting the recording layer as the recording destination. Whether or not (step S108). *

If a mismatch is determined, the controller 83 performs a predetermined error process (step S109). For example, the host device 50 is notified that recording on the multilayer optical disk 11 is impossible due to mismatch of layer information. Alternatively, the position information may be corrected based on the relationship between the read layer information and the provisional layer information used for selecting the recording layer to be recorded, and the focus servo may be pulled again. . *

If coincidence is determined, the controller 83 determines the focused recording layer as the recording layer L1 selected as the recording destination (step S110), for example, the next to be executed for the multilayer optical disc 11 Processing, for example, OPC processing, defect replacement processing, and the like are performed, and then user data is recorded. The above operation is performed in a state where the multilayer optical disc 11 is driven by the CLV method or the CAV method.

(Effect of this embodiment) As mentioned above, in this embodiment, the following effects are acquired. 1. Since the layer information is recorded on each recording layer of the multilayer optical disc 11, it is logically confirmed whether or not the focused recording layer is the recording layer selected as the recording destination of the user data. Data can be recorded. Thereby, it is possible to stably perform recording on each recording layer of the multilayer optical disc 11, and the reliability is improved. *

2. As shown in FIG. 6, the management information of each recording layer of the multilayer optical disc 11 is recorded so that the positions of the recording layers are shifted from each other at least between adjacent recording layers, thereby managing from the lead-in area of one recording layer. It is possible to eliminate an adverse effect caused by interlayer crosstalk when reading information. As a result, the management information in the lead-in area can be satisfactorily read, and the stability of recording and reproduction is improved. *

3. Furthermore, as shown in FIG. 7, the size of the required lead-in area can be further reduced by alternately assigning a plurality of recording layers of three or more to the two small areas of the lead-in area in the stacking order. Thus, the recording capacity of each recording layer can be increased. *

<Second Embodiment>
In the first embodiment, it is assumed that layer information is recorded in the lead-in area of each recording layer of the multilayer optical disc 11. However, the layer information may be recorded in any region as long as it can be obtained from the focused recording layer. For example, it is assumed that layer information is recorded in a BCA (Burst Cutting Area) for each recording layer.

The BCA is formed by partially burning the recording layer with a high-power laser beam during the manufacturing process of the multilayer optical disc. When the light reflectance is different between the burned-out portion and the unburned-out portion, when the multilayer optical disc is rotated and the BCA is focused and irradiated with laser light, for example, as shown in FIG. In addition, a signal whose reflection level changes in two steps, BCAtop and BCAbottom, is obtained. Data (BCA data) is obtained by demodulating and decoding this signal. *

FIG. 11 is an overall plan view of the multilayer optical disk 11A of the present embodiment. FIG. 12 is a detailed plan view of the BCA portion of the multilayer optical disk 11A of FIG. 13 is a cross-sectional view of the multilayer optical disk 11A of FIG. As shown in FIG. 11, a center hole 101 for disc chucking is provided in the center of the multilayer optical disc 11A. A chucking area 102 for disc chucking is also provided on the outer peripheral side of the center hole 101. A BCA 103 is provided on the outer peripheral side of the chucking area 102, and a recording area 104 including a lead-in area is provided on the outer peripheral side thereof. *

As shown in FIGS. 12 and 13, the BCA 103 is provided for each recording layer 113. The BCA 103 for each of the recording layers 113 (recording layers L0, L1, L2, and L3) is “BCA (L0)”, “BCA (L1)”, “BCA (L2)”, and “BCA (L3) as necessary for explanation. ) ”. The BCA 103 for each recording layer 113 is provided at different disk radial positions. For example, the radial positions of the multi-layer optical disc 11A are shifted from the inner circumference side to the outer circumference side so as not to overlap each other, as in BCA (L0), BCA (L1), BCA (L2), and BCA (L3). Arranged in ascending order of layer number values. *

Each BCA 103 for each recording layer 113 has at least a disc ID and layer information recorded in advance (when the multilayer optical disc 11A is manufactured). The disc ID is a serial number unique to the multilayer optical disc 11A, that is, information for identifying the individual of the multilayer optical disc 11A. The layer information is information for identifying individual recording layers 113 (recording layers L0, L1, L2, and L3) of the multilayer optical disc 11A. For example, the BCA (L0) of the recording layer L0 records layer information that can uniquely identify the layer position of the recording layer L0 in the multilayer optical disc 11A. *

The BCA (L0), BCA (L1), BCA (L2), and BCA (L3) are arranged so that the disk radial positions are not shifted from each other, thereby causing interference between the BCAs 103 of the plurality of recording layers 113. The occurrence of reading errors can be suppressed. *

(Configuration of Disk Drive) Next, the configuration of the disk drive of the second embodiment will be described. FIG. 14 is a block diagram showing the configuration of the disk drive 31A of the second embodiment. Here, the BCA processing unit 87 reproduces the disk ID and layer information, which are data recorded in the BCA 103, based on the reproduction RF signal from the first light receiving unit 62, and supplies it to the controller 83A. For example, the controller 83A confirms the number of recording layers designated as the user data recording target based on the layer information reproduced by the BCA processing unit 87, for example, as the recording destination of user data. Confirmation of the alignment between the selected recording layer and the recording layer into which the focus servo is actually drawn is performed. Other configurations are the same as those of the disk drive 31 of the first embodiment. *

(Confirmation of Recording Layer Using Layer Information) FIG. 15 is a flowchart showing an operation of confirming the recording layer by the disk drive 31A of the second embodiment. When the multilayer optical disk 11A is loaded, the controller 83A of the disk drive 31A causes the first light source 33 to emit a laser beam having a power set for searching the recording layer such as a reproduction power. A control command is supplied to the light source driving unit 73. *

Subsequently, the controller 83A moves the focus position of the laser beam for searching the recording layer within a range that allows at least all the recording layers of the multilayer optical disc 11A to pass while the optical pickup 32 is placed at a predetermined initial position. In this manner, the pickup vertical feed mechanism (not shown) is controlled to move (swing) the optical pickup 32 a plurality of times at a constant speed in the optical axis direction of the objective lens 60 (step S201). At this time, the controller 83A changes the position of the first collimator lens 34 every swing in order to probabilistically try to correct the spherical aberration (step S201). *

The controller 83A has an S-curve at the position of the first collimator lens 34 where the amplitude of the S-curve voltage of the target recording layer becomes the maximum among the focus error signals (S-curve voltage) obtained for each swing. The voltage is determined as the S-shaped voltage with the spherical aberration corrected, and the result of binarizing the S-shaped voltage at a predetermined slice level by the binarizing unit 78 is used as the S-shaped curve information of the focus error signal. Obtain (step S202). *

The controller 83A estimates the position of each recording layer in the swing range of the optical pickup 32 based on the acquired S-curve information of the focus error signal, and provisional layer information is added to each estimated recording layer position. And the correlation information is stored in the memory in the controller 83A. Here, the position of each recording layer is expressed by the amount of movement of the optical pickup 32 from the initial position, for example. The temporary layer information is assigned according to the same assignment rule as the layer information actually recorded on the BCA 103 so that the layer information can be compared with the layer information actually recorded on the BCA 103 of each recording layer (step S203). *

Thereafter, a recording layer as a recording destination of user data is selected using temporary layer information. For example, it is assumed that the recording layer L1 is selected as the user data recording destination based on the provisional layer information. The controller 83A reads the position information of the recording layer L1 corresponding to the provisional layer information from the memory, and controls the optical pickup lifting / lowering mechanism (not shown) based on the information, thereby moving the optical pickup 32 from the initial position in the optical axis direction. Move (step S204). *

The controller 83A moves the optical pickup 32 in the disc radial direction to a position where the layer information can be read from the BCA 103 (L1) in the recording layer L1 selected as the user data recording destination (step S205). More specifically, in order to perform this control, the controller 83A reads in advance the position information (disk radius position) of the BCA 103 for each recording layer from the lead-in area of the guide layer and stores the temporary layer in the memory in the controller 83A. It is necessary to store the information in association with it. The controller 83A acquires the position information of the BCA 103 (L1) associated with the temporary layer information of the recording layer L1 selected as the user data recording destination from the memory, and based on this, the BCA 103 in the recording layer L1 is acquired. The feed mechanism is controlled so that the optical pickup 32 is moved in the disk radial direction to a position where the layer information can be read from (L1). *

Subsequently, the controller 83A supplies a control command to the focus control unit 77 so as to start the focus servo pull-in (step S206). Thereby, the laser beam is focused on the recording layer that is closest to the focus position of the laser beam. At this time, whether or not the recording layer is the recording layer L1 designated as the recording destination. Is uncertain. *

Subsequently, the controller 83A performs control so that the BCA processing unit 87 reads layer information from the BCA 103 of the focused recording layer (step S207). *

The controller 83A determines whether or not the layer information read from the BCA 103 of the focused recording layer matches the temporary layer information used for selecting the recording layer as the recording destination (step S208). *

If a mismatch is determined, the controller 83A performs a predetermined error process (step S209). For example, the host device 50 is notified that recording on the multilayer optical disc 11A is impossible due to the mismatch of the layer information. Alternatively, the position information may be corrected based on the relationship between the read layer information and the provisional layer information used for selecting the recording layer to be recorded, and the focus servo may be pulled again. . *

When the coincidence is determined, the controller 83A determines the focused recording layer as the recording layer L1 selected as the recording destination (step S210), and, for example, the next to be executed for the multilayer optical disc 11A. Processing, for example, OPC processing, defect replacement processing, and the like are performed, and then user data is recorded. *

(Effect of 2nd Embodiment) As mentioned above, in this embodiment, the following effects are acquired. After layer information is recorded on each BCA 103 of each recording layer of the multilayer optical disc 11A, it is logically confirmed whether or not the focused recording layer is the recording layer selected as the user data recording destination. Can record user data. Thereby, recording can be stably performed on each recording layer of the multilayer optical disc 11A, and the reliability is improved. *

<Modification 1> As shown in FIG. 13, BCA (L0), BCA (L1), BCA (L2), and BCA (L3) for each recording layer are not interfering with each other during reading. Provided at different disk radius positions. Therefore, by assigning layer information in advance to position information (disk radius position) of BCA (L0), BCA (L1), BCA (L2), and BCA (L3) for each recording layer, the disk drive is focused. Can be determined without depending on the layer information recorded in the BCA 103, and double confirmation can be performed together with the layer information read from the BCA 103. . The specific method will be described below. *

FIG. 16 is a block diagram showing the configuration of the disk drive 31B of this modification. This disk drive 31B is obtained by adding an address reproducing unit 88 to the configuration of the disk drive 31A of the second embodiment. Based on the output of the second light receiving unit 69, the address reproducing unit 88 reproduces physical address information recorded in the guide track of the guide layer 112 after being modulated, for example, into wobbling or a pit row, and supplies it to the controller 83B. To do. *

In the memory of the controller 83B, correlation data in which the position information (disk radius position) of BCA (L0), BCA (L1), BCA (L2), and BCA (L3) for each recording layer is associated with the layer information is stored. Is done. This correlation data is read from, for example, the lead-in area of the guide layer of the multilayer optical disc 11B and stored in the memory. The controller 83B calculates a disk radius position using a predetermined conversion formula or the like based on the physical address information supplied from the address reproducing unit 88, and refers to the correlation data stored in the memory 52 to determine the disk radius. The layer information associated with the position is acquired. Then, the controller 83B determines whether or not the layer information matches the layer information read from the BCA 103. If they match, the controller 83B determines the layer information as the layer information of the focused recording layer. Thereby, it can be logically and more surely confirmed by double determination whether or not the focused recording layer is the recording layer selected as the user data recording destination. *

<Modification 2> The controller 83B calculates the disk radius position using a predetermined conversion formula based on the physical address information supplied from the address reproducing unit 88, and refers to the correlation data stored in the memory. The layer information associated with the disc radius position may be determined as the layer information of the focused recording layer. According to this method, even if no layer information is recorded in the BCA, the controller 83B logically checks whether the focused recording layer is the recording layer selected as the user data recording destination. be able to.

The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 ...

Optical recording system

11, 11A, 11B ... Multi-layer optical disk 31, 31A, 31B ... Disk drive 32 ... Optical pick-up 33 ... First light source 50 ... Host device 51 ... CPU 52 ... Memory 60 ... Objective lens 62 ... First Light receiving unit 77 ... Focus control unit 78 ... Binarization unit 79 ... Focus actuator 83 ... Controller 86 ... Focus error generation unit 87 ... BCA processing unit 88 ... Address reproduction unit 103 ... BCA 112 ... Guide layer 113 ... Recording layer 115 ... Protection Layer 121 ... Guide track

Claims

It has a plurality of recording layers capable of recording information and a guide layer provided with a guide track for tracking, and each of the plurality of recording layers records layer information for identifying its own recording layer. An optical recording apparatus for recording on a multilayer optical disc having a layer information recording area, a light source that emits a light beam, an objective lens that focuses the light beam on the multilayer optical disc, and light reflected by the multilayer optical disc A light receiving unit that receives the beam and outputs an electric signal; a focus error generating unit that generates a focus error signal from the output of the light receiving unit; and a range in which the focus position of the light beam passes through at least the plurality of recording layers Based on the waveform of the focus error signal generated by the focus error generator along with the movement, The estimated recording layer position, assigning temporary layer information to each of the estimated recording layer positions, and using the temporary layer information, the estimated recording layer selected as a user data recording destination. The focus servo is turned on from the state in which the focus is adjusted to read the layer information from the layer information recording area of the recording layer into which the focus servo is drawn, and the read layer information and the user data are recorded. Compared with the provisional layer information used to select the recording layer as the destination, and if they match, the recording layer into which the focus servo is drawn is determined as the recording layer selected as the recording destination of the user data. An optical recording apparatus comprising a control unit.
Management including a plurality of recording layers capable of recording information and a guide layer provided with a guide track for tracking, each of the plurality of recording layers including layer information for identifying its own recording layer An optical recording method for recording on a multi-layer optical disc having a layer information recording area in which information is recorded, wherein the focus position of the light beam is moved within at least a range passing through the plurality of recording layers, and accompanying this movement Based on the generated focusing error signal waveforms, the positions of the plurality of recording layers are estimated, temporary layer information is allocated to the estimated positions of the plurality of recording layers, and the temporary layer information is used. When the focus servo is turned on from the state where the estimated position of the recording layer selected as the user data recording destination is focused, the focus servo is turned on. The layer information is read from the layer information recording area of the recording layer to be included, and the read layer information is compared with the temporary layer information used for selecting the recording layer as the recording destination of the user data. If they coincide with each other, an optical recording method in which the recording layer into which the focus servo is drawn is determined as the recording layer selected as the recording destination of the user data.
A plurality of recording layers capable of recording information, and a guide layer provided with a guide track for tracking, wherein each of the plurality of recording layers includes layer information for identifying its own recording layer A multi-layered optical disc having a lead-in area in which information is recorded, and the lead-in area is disposed so as to be shifted from each other between adjacent recording layers.
The multilayer optical disc according to claim 3, wherein management information including the layer information is recorded in advance in the lead-in area.
It has a plurality of recording layers capable of recording information and a guide layer provided with a guide track for tracking, and each of the plurality of recording layers records layer information for identifying its own recording layer in advance. A multi-layered optical disk having a BCA (Burst_Cutting_Area), wherein the BCAs of the plurality of recording layers are arranged at different disk radial positions.
6. The multilayer optical disk according to claim 5, wherein a disk identifier for identifying the multilayer optical disk is further recorded in advance on the BCA.