JP2009129497A - Optimum recording power setting method, recording method, and optical disk drive - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve an optimum recording power setting method by which optimum recording power when information is recorded in a multi-layer optical disk can be set, to provide a recording method by which recording can be performed with more stable recording quality by setting optimum recording power using the method, and to provide an optical disk drive. <P>SOLUTION: In the optimum recording power setting method by which optimum recording power is set by irradiating the trial writing region of a multi-layer optical disk having recording layers of three layers or more with a laser beam, performing trial writing by changing recording power of the laser beam, measuring modulation degree of a trial writing results, and setting optimum recording power, the modulation degree in which effect of reflected light (flare light) from the recording layer other than a recording layer to which trial writing is performed is excluded is used. For example, optimum recording power can be obtained in the same way as two layers optical disk even in three layers optical disk by calculating the modulation degree in which influence of the flare light is excluded using a value pre-formatted in the disk, for example. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optimum recording power setting method, a recording method, and an optical disc apparatus, and more specifically, an optimum recording power setting method for recording information on an optical disc having a plurality of recording layers capable of rewriting information, and The present invention relates to a recording method for recording information by setting an optimum recording power using the optimum recording power setting method, and an optical disc apparatus for recording information on the optical disc using the recording method.

  In recent years, with the advancement of digital technology and the improvement of data compression technology, as a medium for recording information (hereinafter also referred to as “content”) such as music, movies, photos and computer software, such as DVD (digital versatile disc) Optical discs have attracted attention, and along with the reduction in price, optical disc apparatuses that use optical discs as information recording media have become widespread.

  In an optical disc apparatus, information is recorded by forming a micro-spot of laser light on a recording surface on which spiral or concentric tracks of an optical disc are formed, and information is reproduced based on reflected light from the recording surface. Is going. This optical disc apparatus is provided with an optical pickup device for irradiating the recording surface of the optical disc with laser light and receiving reflected light from the recording surface.

  Usually, the optical pickup device includes an objective lens, and guides the light beam emitted from the light source to the recording surface of the optical disc and guides the return light beam reflected by the recording surface to a predetermined light receiving position, which is disposed at the light receiving position. Lens driving device for driving the optical detector and the objective lens in the optical axis direction (hereinafter referred to as “focus direction”) and the direction orthogonal to the tangential direction of the track (hereinafter referred to as “tracking direction”) Etc. From the photodetector, a signal including not only reproduction information of data recorded on the recording surface but also information (servo information) necessary for position control of the objective lens is output.

In an optical disc, information is recorded by the lengths and combinations of marks and spaces having different reflectivities.
For example, a recordable DVD such as DVD + RW (DVD + rewritable) and DVD + R (DVD + recordable) has a light emission power pulse shape or the like based on a rule (method) relating to the light emission pulse shape or the like called a recording strategy.
In the optical disc apparatus, a test called a PCA (Power Calibration Area) set in advance prior to recording of information so that a mark and a space of a target length are formed at the target position of the optical disc at the time of recording. Trial writing is performed in the writing area to obtain the optimum recording power (for example, see Non-Patent Document 1). This process is called an OPC (Optimum Power Control) process.

Incidentally, the amount of content information tends to increase year by year, and further increase in the recording capacity of the optical disc is expected. Thus, as one of means for increasing the recording capacity of the optical disc, it is conceivable to make the recording layer multi-layered. The development of equipment is being actively conducted. Also, it is important to obtain an appropriate recording power even in a multilayer optical disc, and various proposals have been made regarding OPC processing (see, for example, Patent Documents 1 and 2).
However, in a recordable multilayer optical disk, for example, when the number of recording layers is three or more, the recording quality may vary even if recording is performed with the optimum recording power obtained by the OPC process.

Japanese Patent No. 3895354 JP 2007-115386 A ECMA-337 "Data Interchange on 120mm and 80mm Optical Disk using + RW Format Capacity: 4.7 and 1.46 Gbytes per Side" December 2003

This will be described below with reference to the drawings.
FIG. 5 is a diagram showing the state of reflected light from the double-layer optical disk 15. The two-layer optical disk 15 has two recording layers L0 and L1. FIG. 5 shows a state in which the laser beam from the objective lens 60 of the optical pickup is focused on L1, and flare light from L0 is included in the reflected light from the two-layer optical disk 15 in addition to the readout light from L1. ing.

FIG. 6 is a diagram showing the relationship between the amount of reflected light from the double-layer optical disc 15 and defocusing. There are reflected light from L0 and reflected light from L1, but since the actual light cannot be distinguished, the reflected light from the whole becomes the amount of received light. As shown in this figure, in the two-layer optical disc 15, when the laser light from the optical pickup is in focus at L1, the influence of the flare light from L0 is very small. Conversely, when L0 is focused on the laser light from the objective lens 60 of the optical pickup, the influence of flare light from L1 is very small. In other words, it can be said that the double-layer optical disk 15 was designed to minimize the influence of flare from adjacent layers.
However, today, where the recording capacity of optical discs is expected to increase further, the number of layers of three or more layers is required.

  FIG. 7 is a diagram showing the state of reflected light from the three-layer optical disk 15. The three-layer optical disk 15 has three recording layers L0, L1, and L2. FIG. 7 shows a state in which the laser beam from the objective lens 60 of the optical pickup is focused on L1. In addition to the readout light from L1, flare light from L0 and flare light from L2 are also transmitted from the three-layer optical disk 15. Is included in the reflected light.

  FIG. 8 is a diagram showing the relationship between the amount of reflected light from the three-layer optical disk 15 and the defocusing. There are reflected light from L0, reflected light from L1, and reflected light from L2, but since it cannot actually be distinguished, the reflected light from the whole becomes the amount of received light. As shown in this figure, in the three-layer optical disk 15, when the laser light from the optical pickup is focused on L1, the influence of the flare light from L0 and the flare light from L2 is very large.

  For example, the OPC method in Non-Patent Document 1 is called a so-called γ method, and employs a method of calculating the optimum recording power from the relationship between the recording power and the modulation degree of the reproduction signal (Non-Patent Document 1). , P.93, Annex H, H.1).

A case where OPC is performed on the L1 layer of the two-layer optical disk and the L1 layer of the three-layer optical disk using the γ method will be described with reference to FIG.
In the γ method, recording is performed while changing the recording power Pw, the degree of modulation m is measured when the recorded result is reproduced, and γ = (dm / dPw) / (Pw / m) is calculated from the degree of modulation m. In this method, a value Pp obtained by multiplying Pw where γ = γtarget is multiplied by ρ is set as the optimum recording power.

In the case of the L1 layer of the dual-layer optical disk, Pw2 where γ = γtarget is set as Ptarget2. A value Pp2 obtained by multiplying Ptarget2 by ρ (value of 1 or more) is set as the optimum recording power.
Further, in the case of the L1 layer of the three-layer optical disk, Pw where γ = γtarget is set as Ptarget3. A value Pp3 obtained by multiplying Ptarget3 by ρ (value of 1 or more) is set as the optimum recording power.

As shown in FIG. 9, when OPC is performed using the γ method, the optimum recording power Pp3 of the three-layer optical disk is lower than the optimum recording power Pp2 of the two-layer optical disk.
That is, when information is recorded on a three-layer optical disk, recording is performed with a low recording power, and a desired recording quality cannot be obtained.

  The present invention has been made in view of the above circumstances, and provides an optimum recording power setting method capable of setting an optimum recording power when recording information on an optical disc having a plurality of rewritable recording layers. An object of the present invention is to provide a recording method capable of recording with stable recording quality by setting the optimum recording power using the optimum recording power setting method, and further using the recording method. An object of the present invention is to provide an optical disc apparatus capable of recording with stable recording quality.

In order to achieve the above object, the present invention employs the following solutions.
The first means of the present invention irradiates a test writing area of a multilayer optical disc having three or more recording layers with laser light, changes the recording power of the laser light, performs test writing, and modulates the test writing result. In the optimum recording power setting method in which the optimum recording power is measured by measuring the degree of modulation, the modulation degree excluding the influence of reflected light (hereinafter referred to as flare light) from recording layers other than the recording layer on which test writing is performed should be used. It is characterized by.
According to a second means of the present invention, in the optimum recording power setting method of the first means, a modulation factor excluding the influence of flare light is calculated using a value preformatted on the multilayer optical disk. Features.
Further, according to a third means of the present invention, in the optimum recording power setting method of the second means, the value preformatted on the multilayer optical disk has no modulation degree affected by flare light and no influence by flare light. It is characterized by the ratio to the modulation factor.
Further, the fourth means of the present invention is characterized in that, in the optimum recording power setting method of the third means, the value preformatted on the multilayer optical disk is a recording layer interval.

According to a fifth means of the present invention, in the recording method for recording information by irradiating a multilayer optical disk having three or more recording layers with laser light, the optimum recording power setting of any one of the first to fourth means is set. A method is used to set an optimum recording power of the laser beam and record information.
According to a sixth aspect of the present invention, there is provided an optical disc apparatus that records or reproduces information by irradiating a multilayer optical disc having three or more recording layers with laser light, and uses the recording method of the fifth means. It is characterized by recording.

In the first means of the present invention, laser light is irradiated to a test writing area of a multilayer optical disc having three or more recording layers, the test power is changed by changing the recording power of the laser light, and the test writing result is modulated. In the optimum recording power setting method for measuring the degree of measurement and setting the optimum recording power, three layers are obtained by using the modulation degree excluding the influence of the reflected light (flare light) from the recording layer other than the recording layer on which trial writing is performed. Even in the case of an optical disc, it is possible to obtain an optimum recording power as in the case of a two-layer optical disc.
In the second means of the present invention, in the optimum recording power setting method of the first means, the modulation degree excluding the influence of flare light is calculated by using the value preformatted on the disk. Even in the case of a double-layer optical disk, it is possible to obtain an optimum recording power as in the case of a double-layer optical disk.
Further, according to the third means of the present invention, in the optimum recording power setting method of the second means, the value α (α = (degree of modulation affected by flare light) / (flare light influence) preformatted on the disk is used. By using the modulation degree without influence)), it is possible to obtain an optimum recording power in the case of a three-layer optical disk as in the case of a two-layer optical disk.
Further, in the fourth means of the present invention, in the optimum recording power setting method of the third means, α is obtained from the recording layer interval preformatted on the disc, and the obtained α is used to obtain three layers. Even in the case of an optical disc, it is possible to obtain an optimum recording power as in the case of a two-layer optical disc.

According to a fifth means of the present invention, in a recording method for recording information by irradiating a multilayer optical disc having three or more recording layers with laser light, the optimum recording power setting of any one of the first to fourth means is set. By setting the optimum recording power of the laser beam using the method and recording information, it is possible to realize a recording method capable of recording with stable recording quality.
According to a sixth means of the present invention, information is recorded using the recording method of the fifth means in an optical disk apparatus that records or reproduces information by irradiating a multilayer optical disk having three or more recording layers with laser light. By performing this recording, it becomes possible to realize an optical disc apparatus capable of recording with stable recording quality.

  Hereinafter, an optimum recording power setting method, a recording method, and an optical disc apparatus according to the present invention will be described in detail with reference to FIGS. 1 to 4 and FIG.

FIG. 1 is a block diagram showing a schematic configuration of an optical disc apparatus 20 according to an embodiment of the present invention.
An optical disk device 20 shown in FIG. 1 includes a spindle motor 22 that rotates and drives an optical disk 15 according to an embodiment of the present invention, an optical pickup device 23, a seek motor 21 that drives the optical pickup device 23 in a sledge direction, and a laser. A control circuit 24, an encoder 25, a drive control circuit 26, a reproduction signal processing circuit 28, a buffer RAM 34, a buffer manager 37, an interface 38, a flash memory 39, a CPU 40, a RAM 41, and the like are provided. Note that the arrows in FIG. 1 indicate the flow of typical signals and information, and do not represent the entire connection relationship of each block. In this embodiment, it is assumed that the optical disc apparatus 20 is compatible with a multilayer optical disc.

The optical disc 15 is incident with a light beam from one surface, and has three recordable recording layers as an example. That is, the optical disk 15 is a recordable single-sided three-layer optical disk, and has three recording layers L0, L1, and L2 in order from the light incident surface as shown in FIG. Yes.
For example, the data zone in each recording layer has a radial position between 24.0 mm and 58.0 mm. Then, it is possible to provide a drive test zone which is a test writing area of each layer at a position avoiding the data zone of 24.0 mm to 58.0 mm in each recording layer. For example, each drive test zone may be provided between 23.4 mm and 23.75 mm in the radial position and between 58.1 mm and 58.25 mm in the radial position. That is, here, the test writing area is provided in the inner peripheral portion and the outer peripheral portion of each recording layer. Hereinafter, for convenience, the drive test zone is also referred to as “PCA (Power Calibration Area)”.

  The optical pickup device 23 condenses laser light on a recording layer to be accessed (hereinafter abbreviated as “target recording layer”) of the two recording layers of the optical disc 15 and receives reflected light from the optical disc 15. It is a device for doing. As shown in FIG. 2 as an example, the optical pickup device 23 includes a light source unit 51, a coupling lens 52, a polarizing beam splitter 54, a quarter wavelength plate 55, an objective lens 60, a condenser lens 58, and a photodetector. And a driving system AC for driving the objective lens 60, and the like.

The light source unit 51 includes a semiconductor laser LD as a light source that emits laser light having a wavelength corresponding to the optical disk 15 (here, about 660 nm). In this embodiment, the maximum intensity emission direction of the laser light emitted from the light source unit 51 is defined as the + X direction. As an example, it is assumed that a light beam of polarized light (P-polarized light) parallel to the incident surface of the polarization beam splitter 54 is emitted from the light source unit 51.
The coupling lens 52 is disposed on the + X side of the light source unit 51, and the light beam emitted from the light source unit 51 is made to be substantially parallel light.

The polarization beam splitter 54 is disposed on the + X side of the coupling lens 52. The polarization beam splitter 54 has a different reflectance depending on the polarization state of the incident light beam. Here, for example, the polarization beam splitter 54 is set so that the reflectance with respect to the P-polarized light is small and the reflectance with respect to the S-polarized light is large. That is, most of the light beam emitted from the light source unit 51 can pass through the polarization beam splitter 54. The quarter-wave plate 55 is disposed on the + X side of the polarization beam splitter 54.
The quarter wavelength plate 55 gives an optical phase difference of a quarter wavelength to the incident light beam. The objective lens 60 is disposed on the + X side of the quarter-wave plate 55 and condenses the light beam that has passed through the quarter-wave plate 55 on the target recording layer. Here, the NA (numerical aperture) of the objective lens 60 is 0.60.

  The detection lens 58 is arranged on the −Z side of the polarization beam splitter 54 and condenses the return light beam branched in the −Z direction by the polarization beam splitter 54 on the light receiving surface of the light receiver PD. This light receiver PD includes a plurality of light receiving elements (or light receiving regions) for generating an optimum signal (photoelectric conversion signal) for detecting an RF signal, a wobble signal, a servo signal, and the like in the reproduction signal processing circuit 28. It is configured to include.

  The drive system AC includes a focusing actuator for minutely driving the objective lens 60 in the focus direction that is the optical axis direction of the objective lens 60 and a tracking actuator for minutely driving the objective lens 60 in the tracking direction. .

Next, the operation of the optical pickup device 23 configured as described above will be briefly described.
The light beam of linearly polarized light (here P-polarized light) emitted from the light source unit 51 becomes substantially parallel light by the coupling lens 52 and enters the polarization beam splitter 54. Most of this light beam passes through the polarization beam splitter 54 as it is, is circularly polarized by the quarter-wave plate 55, and is condensed as a minute spot on the target recording layer of the optical disk 15 via the objective lens 60. The reflected light from the optical disk 15 becomes circularly polarized light in the direction opposite to the outward path, and is converted into a substantially parallel light again by the objective lens 60 as a return light beam. ). The return light beam enters the polarization beam splitter 54. The return light beam reflected in the −Z direction by the polarization beam splitter 54 is received by the light receiver PD via the detection lens 58. In the light receiver PD, photoelectric conversion is performed for each light receiving element (or light receiving region), and each photoelectric conversion signal is output to the reproduction signal processing circuit 28.

  Returning to FIG. 1, the reproduction signal processing circuit 28, based on the output signal (a plurality of photoelectric conversion signals) of the light receiver PD, servo signals (focus error signal, track error signal, etc.), address information, synchronization information, An RF signal or the like is acquired. The servo signal obtained here is output to the drive control circuit 26, the address information is output to the CPU 40, and the synchronization signal is output to the encoder 25, the drive control circuit 26, and the like. Further, the reproduction signal processing circuit 28 performs decoding processing, error detection processing, and the like on the RF signal. When an error is detected, the reproduction signal processing circuit 28 performs error correction processing, and then plays back the buffer via the buffer manager 37 as reproduction data. Store in the RAM 34. The address information included in the reproduction data is output to the CPU 40.

  The drive control circuit 26 generates a drive signal for the tracking actuator for correcting the displacement of the objective lens 60 in the tracking direction based on the track error signal from the reproduction signal processing circuit 28. Further, the drive control circuit 26 generates a drive signal for the focusing actuator AC for correcting the focus shift of the objective lens 60 based on the focus error signal from the reproduction signal processing circuit 28. The drive signals for the actuators generated here are output to the optical pickup device 23. Thereby, tracking control and focus control are performed. Furthermore, the drive control circuit 26 generates a drive signal for driving the seek motor 21 and a drive signal for driving the spindle motor 22 based on an instruction from the CPU 40. The drive signal of each motor is output to the seek motor 21 and the spindle motor 22, respectively.

  The buffer RAM 34 temporarily stores data to be recorded on the optical disc 15 (recording data), data reproduced from the optical disc 15 (reproduction data), and the like. Data input / output to / from the buffer RAM 34 is managed by the buffer manager 37.

  The encoder 25 takes out the recording data stored in the buffer RAM 34 through the buffer manager 37 based on an instruction from the CPU 40, modulates the data, adds an error correction code, and the like, and writes a signal to the optical disc 15. Is generated. The write signal generated here is output to the laser control circuit 24.

  The laser control circuit 24 controls the light emission power of the semiconductor laser LD. For example, at the time of recording, a drive signal for the semiconductor laser LD is generated by the laser control circuit 24 based on the write signal, recording conditions, light emission characteristics of the semiconductor laser LD, and the like.

  The interface 38 is a bidirectional communication interface with a host device 90 (for example, a personal computer), and is a standard interface such as ATAPI (AT Attachment Packet Interface), SCSI (Small Computer System Interface), and USB (Universal Serial Bus). Is compliant.

  The flash memory 39 stores various programs including a program according to an embodiment of the present invention described by codes readable by the CPU 40, and various data such as light emission characteristics of the semiconductor laser LD.

  The CPU 40 controls the operation of each unit in accordance with the program stored in the flash memory 39 and stores data necessary for control in the RAM 41 and the buffer RAM 34.

Next, processing in the optical disc device 20 when a recording request is received from the host device 90 will be described with reference to the flowchart of FIG.
The flowchart in FIG. 3 corresponds to a series of processing algorithms executed by the CPU 40. When the recording request command is received from the host device 90, the start address of the program corresponding to the flowchart of FIG. 3 stored in the flash memory 39 (hereinafter referred to as “recording processing program”) is set in the program counter of the CPU 40. The recording process starts.

  In the first step 401, the drive control circuit 26 is instructed to rotate the optical disc 15 at a predetermined linear velocity (or angular velocity), and the reproduction signal processing circuit 28 is notified that the recording request command has been received from the host device 90. To do. As an example, the recording scanning speed is 9.19 m / s (corresponding to 2.4 times the speed of DVD).

In the next step 402, calibration conditions and recording strategy information recorded on the optical disc 15 are acquired via the reproduction signal processing circuit 28. Here, the reproduction signal processing circuit 28 phase-demodulates the wobble signal detected for each layer, extracts calibration conditions and recording strategy information for each layer, and sets recording conditions. Various parameters defining the emission waveform of the semiconductor laser LD are set in a register (not shown) of the laser control circuit 24.
In the next step 403, an OPC process is performed based on the calibration information and recording conditions acquired in step 402 to obtain an optimum recording power Pp.

Next, details of the OPC process will be described.
In FIG. 9, recording is usually performed while changing the recording power Pw, and the degree of modulation m when the recorded result is reproduced is measured, and γ = (dm / dPw) / (Pw / m) is calculated from the degree of modulation m. A value Pp obtained by multiplying Pw where γ = γtarget is multiplied by ρ is set as the optimum recording power. γtarget and ρ have been acquired as calibration information.
However, as described above, in the case of the L1 layer of the three-layer optical disk, Pw where γ = γtarget is set as Ptarget3. That is, a value Pp3 obtained by multiplying Ptarget3 by ρ (a value of 1 or more) is set as the optimum recording power.

  Therefore, the present invention corrects the degree of modulation m from the actually measured value. For example, a correction coefficient α is recorded in advance on the optical disc as calibration information, and calculation is performed with mα as a true modulation degree. By doing so, the optimum recording power can be obtained in the same manner as L1 of the double-layer optical disk in FIG.

Here, for example, the correction coefficient α is α = 1.5 or a value of 1 or more. That means
α = (modulation degree with influence of flare light) / (modulation degree without influence of flare light)
It is. Α can also be determined from the layer spacing between adjacent layers.
For example, α can be obtained from the relationship shown in FIG. That is, it is also possible to record the layer spacing with the adjacent layer on the optical disc in advance as calibration information.
In the next step 404, user data is recorded on the target recording layer with the optimum recording power obtained from the above.

As is clear from the above description, in the optical disk device 20 according to the present embodiment, the flash memory 39 constitutes a memory, and the encoder 25 and the laser control circuit 24 constitute a processing device. Further, the CPU 40 constitutes a control computer.
In the present embodiment, among the programs stored in the flash memory 39, the recording processing program includes the program according to the present invention. In the recording process, the recording method according to the present invention is performed.

  In the above embodiment, the case where the calibration information and the recording strategy information corresponding to each recording layer are individually recorded for each recording layer has been described. However, the present invention is not limited to this. All of the calibration information and the recording strategy information corresponding to each recording layer may be recorded only in the recording layer.

In the above-described embodiment, the case where the calibration information and the recording strategy information are set for each recording layer has been described. However, the present invention is not limited to this. Calibration information and recording strategy information may be set and recorded in any recording layer.
Further, in the above-described embodiment, the description has been given of the case where the test writing area is provided in each of the inner peripheral part and the outer peripheral part of the optical disc. Also good.
In the above embodiment, the case where the test writing area on the inner periphery of the disk is provided between the radius positions of 23.4 mm and 23.75 mm has been described. However, the present invention is not limited to the radius positions.
In the above embodiment, the case where the test writing area on the outer periphery of the disk is provided between the radius positions of 58.1 mm and 58.25 mm has been described. However, the present invention is not limited to the radius positions.

  Furthermore, in the above embodiment, the program according to the present invention is recorded in the flash memory 39, but is recorded in another recording medium (CD, magneto-optical disk, DVD, memory card, USB memory, flexible disk, etc.). May be. In this case, the program according to the present invention is loaded into the flash memory 39 via the playback device (or dedicated interface) corresponding to each recording medium. Further, the program according to the present invention may be transferred to the flash memory 39 via a network (LAN, intranet, Internet, etc.). In short, it is sufficient that the program according to the present invention is stored in the flash memory 39.

  In the above-described embodiment, the case where the optical disk 15 is a DVD-based information recording medium has been described. However, the present invention is not limited to this, and for example, a CD-based rewritable single-sided multilayer optical disk, a wavelength of A rewritable single-sided multilayer optical disc corresponding to a light beam of 405 nm may be used. In this case, for example, in a CD having a numerical aperture of the objective lens 60 of the optical pickup device 23: NA = 0.5 and wavelength: λ = 780 nm, the track pitch is 1.6 μm, NA = 0.65, λ = 405 nm. In the HD DVD, the track pitch is 0.4 μm.

  Furthermore, although the case where the optical pickup device 23 includes one semiconductor laser has been described in the above embodiment, the present invention is not limited thereto, and for example, a plurality of semiconductor lasers that emit light beams having different wavelengths may be included. In this case, for example, at least one of a semiconductor laser that emits a light beam with a wavelength of about 405 nm, a semiconductor laser that emits a light beam with a wavelength of about 660 nm, and a semiconductor laser that emits a light beam with a wavelength of about 780 nm may be included. . That is, the optical disk apparatus 20 may be an optical disk apparatus that supports a plurality of types of optical disks that conform to different standards. At this time, it is sufficient that at least one of the plural types of optical discs is a rewritable single-sided multilayer optical disc.

  As described above, according to the recording method and the optical disc apparatus using the optimum recording power setting method of the present invention, it is suitable for recording on an optical disc having a plurality of rewritable recording layers with stable recording quality. . Therefore, according to the present invention, it is possible to realize a recording method and an optical disc apparatus that can perform recording with stable recording quality.

1 is a diagram illustrating an embodiment of the present invention, and is a block diagram illustrating a schematic configuration of an optical disc apparatus. It is a schematic block diagram which shows the structural example of the optical pick-up apparatus with which the optical disk apparatus of FIG. 1 is equipped. 3 is a flowchart showing an example of a recording process in the optical disc apparatus of FIG. It is a figure which shows the relationship between the space | interval with the adjacent layer of a multilayer optical disk, and correction coefficient (alpha). It is the figure which showed the condition of the reflected light from a 2 layer optical disk. It is the figure which showed the relationship between the received light quantity of the reflected light from a two-layer optical disk, and defocusing. It is the figure which showed the condition of the reflected light from a 3 layer optical disk. It is the figure which showed the received light amount of the reflected light from a 3 layer optical disk, and the relationship of defocusing. It is explanatory drawing at the time of performing OPC for the L1 layer of a two-layer optical disk and the L1 layer of a three-layer optical disk using the γ method.

Explanation of symbols

15: Multi-layer optical disk 20: Optical disk device 21: Seek motor 22: Spindle motor 23: Optical pickup device 24: Laser control circuit 25: Encoder 26: Drive control circuit 28: Reproduction signal processing circuit 34: Buffer RAM
37: Buffer manager 38: Interface 39: Flash memory 40: CPU
41: RAM
51: Light source unit 52: Coupling lens 54: Polarizing beam splitter 55: 1/4 wavelength plate 58: Condensing lens 60: Objective lens 90: Host device (personal computer, etc.)
AC: Drive system (focusing actuator, tracking actuator)
PD: light receiver L0, L1, L2: recording layer

Claims (6)

The test writing area of a multilayer optical disc having three or more recording layers is irradiated with laser light, test writing is performed by changing the recording power of the laser light, and the modulation degree of the test writing result is measured to obtain the optimum recording power. In the optimum recording power setting method to be set,
An optimum recording power setting method characterized by using a modulation degree excluding the influence of reflected light (hereinafter referred to as flare light) from a recording layer other than the recording layer on which trial writing is performed. In the optimal recording power setting method according to claim 1,
An optimum recording power setting method, wherein a modulation degree excluding the influence of flare light is calculated using a value preformatted on the multilayer optical disc. In the optimum recording power setting method according to claim 2,
An optimum recording power setting method characterized in that the value preformatted on the multilayer optical disc is a ratio between a modulation factor affected by flare light and a modulation factor not affected by flare light. In the optimum recording power setting method according to claim 3,
An optimum recording power setting method, wherein the value preformatted on the multilayer optical disc is a recording layer interval. In a recording method for recording information by irradiating a multilayer optical disc having three or more recording layers with laser light,
5. A recording method for recording information by setting an optimum recording power of the laser beam using the optimum recording power setting method according to any one of claims 1 to 4. In an optical disc apparatus for recording or reproducing information by irradiating a multi-layer optical disc having three or more recording layers with laser light,
6. An optical disc apparatus that records information using the recording method according to claim 5.

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