JP2012038382A - Optical disk drive and spindle control method - Google Patents

Abstract

A spindle motor rotational speed control time suitable for an inserted medium in an optical disc apparatus for recording or reproducing information on a multilayer optical disc having a plurality of recording surfaces and corresponding to the number of recording surfaces and having different recording densities. To shorten.
The rotational speed of a spindle motor is set to an optimal value in advance before reading BCA management information in accordance with the number of layers determined by layer number discrimination based on a focus error signal after insertion of an optical disk.
[Selection] Figure 2

Description

  The present invention relates to a process of controlling a spindle rotational speed that varies depending on the number of layers on a multilayer optical disk having a plurality of recording surfaces and having different recording densities depending on the number of recording surfaces, and records or reproduces information on the multilayer optical disk. The present invention relates to an optical disc device.

  The disc rotation speed of the optical disc is controlled by an FG control mode in which control is performed based on an FG signal obtained from a spindle motor drive circuit for rotating the disc, and a track formed by wobbling on the disc in a cycle of a predetermined length. It has a wobble control mode in which control is performed based on a wobble signal obtained by reproduction. The FG control mode is used when a reproduction signal from the disk cannot be obtained, and is used when control is performed so that the rotation speed is approximately a predetermined rotation speed when the disk reproduction is started. By switching to the wobble control mode when the rotation speed at which the wobble signal can be reproduced from the disc is reached in the FG control mode, high-precision control is performed so that the wobble signal reproduced from the disc has a predetermined frequency. Recording or reproduction is performed at a transfer rate of.

JP 2002-93034 A JP 2009-193618 A JP 2006-309809 A

Proc. of SPIE Vol. 6282 628212, 1-8, "High-denity multilayer optical disc storage"

  As the amount of data handled by individuals increases year by year due to the development of digital media, optical disks have been increased in capacity from CD to DVD and from DVD to BD due to the shorter wavelength of lasers. In recent years, terrestrial digital broadcasting has been started, and in order to record high-definition moving images for a long time, further increase in capacity of an optical disk is required. One of the means for achieving this is a method of multilayering optical discs, and double-layer discs have already been put to practical use in DVDs and BDs, but for the purpose of further increasing the capacity, multi-layer discs having three or more layers of BDs. Standardization is expected. In addition, the recording capacity per recording surface is increased by increasing the linear recording density together with the multi-layer, and the optical disk having a capacity double or more than that of the conventional double-layer disk by combining the multi-layer and the high density. (Non-Patent Document 1).

  The length of the wobble period of a track formed on an optical disc differs between a normal linear recording disc and an optical disc with increased linear recording density. For this reason, when control is performed so that the wobble signal reproduced from the disc has a predetermined frequency in the wobble control mode, the linear velocity is different between an optical disc having a normal linear recording density and an optical disc having a higher linear recording density. . For example, a BD currently commercialized has a recording capacity per recording layer of 25 GB, whereas an optical disc with a recording capacity per recording layer of 33 GB has a rotational speed of 25/33 at the same radial position. = 0.76 times, and the rotational speed is reduced by 20% or more. For this reason, as a method for discriminating the recording density of the optical disc, for example, when the discriminating method is based on the information recorded on the BCA (Burst Cutting Area) formed on the inner periphery of the optical disc shown in FIG. When the BCA is reproduced with a rotational speed corresponding to the recording density and discriminated as an optical disc with a different recording density, it is necessary to change the rotational speed to a disc recording density.

  FIG. 7 shows a spindle control process in the case where the recording density of the optical disc is determined by BCA.

  In FIG. 7, when an optical disc is inserted (S701), it is determined whether the inserted optical disc is a CD, a DVD, or a BD (S702). As a determination method, for example, as in Patent Document 3, the focus error amount and reflection obtained when the objective lens is brought close to or away from the optical disk while the laser corresponding to each disk type is emitted. A determination method based on the amplitude of a signal indicating the amount of light is used. If it is discriminated as a CD or DVD by the branching process depending on the disc type (S703), a spindle control process corresponding to the CD or DVD is performed (S704). If it is determined as BD, the target rotational speed Nt is set to the rotational speed N25 corresponding to the normal density (S705). Next, the spindle control mode is set to the FG control mode (S706), the spindle control is started, and the optical disk is rotated (S707). Next, focus pull-in is performed, and focus control is started so that the light spot is focused on a predetermined recording layer (S708). The condensed light spot is moved to the BCA portion formed on the inner peripheral portion of the optical disc, and the BCA is reproduced (S709). The recording density of the inserted optical disk is discriminated based on the information unique to the disk obtained by reproducing the BCA (S710). When the recording capacity of the optical disk is 33 GB, the rotational speed N33 corresponding to the target rotational speed Nt is high. The setting is changed to (S711). The rotation speed of the optical disk is monitored (S712), and when the wobble signal reaches a reproducible rotation speed, for example, within 10% of the target rotation speed, the wobble control mode is switched (S713). Through the above processing, spindle control corresponding to the type of disk and the recording density is performed.

  In the above processing, it is necessary to change the target rotation speed when a high-density BD is inserted. If the target rotational speed in step S705 is set to a high density (Nt = N33), it is necessary to change the target rotational speed when a normal density BD is inserted.

  Also, in the method of discriminating the type of the disc based on the frequency of the wobble signal reproduced as in Patent Document 2, the frequency of the wobble signal is once set to a rotational speed corresponding to a normal or high-density disc in the FG control mode. If the disk is detected and discriminated to have a different density, it is necessary to change to a rotational speed corresponding to the recording density of the disk.

  In either case, it takes time to reach a rotational speed corresponding to the density of the inserted optical disk. In particular, since the torque of the spindle motor of a thin optical disk device mounted on a notebook personal computer is small, it takes time to change the rotational speed. For this reason, the setup time from when the disc is set to the optical disc apparatus until recording or reproduction becomes possible becomes long.

  It is an object of the present invention to provide an optical disc apparatus capable of reducing a change in rotational speed and shortening a setup time even in a multilayer optical disc having different recording densities.

  In order to improve the above-described problem, the present invention uses the configuration described in the claims as an example.

  According to the multilayer optical disc recording / reproducing method of the present invention, in a multilayer optical disc having a plurality of recording surfaces and having different recording densities depending on the number of recording surfaces, the rotation speed at the start of spindle control is set corresponding to the recording density. Therefore, it is not necessary to change the rotation speed, and the setup time can be shortened.

1 is a block diagram showing a schematic configuration of an optical disc apparatus according to an embodiment of the present invention. 6 is a flowchart showing a processing procedure of spindle control according to the number of layers in the optical disc apparatus according to the present invention. It is explanatory drawing which showed the focus error signal with respect to each recording layer from the surface at the time of the focus position scan in the optical disk device based on this invention. 6 is a flowchart showing a processing procedure of spindle control according to the number of layers when the number of layers and the type of the optical disc are determined in the same area in the optical disc apparatus according to the present invention. It is explanatory drawing which showed the pull-in error signal with respect to each recording layer from the surface at the time of the focus position scan in the optical disk device based on this invention. It is a figure which shows the recording form of BCA in an optical disk. It is a flowchart which shows the process sequence of the spindle control in the case of discriminating the recording density of an optical disk by BCA.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings in the examples.

FIG. 1 is an overall block diagram of an optical disc apparatus that records or reproduces information on an optical disc 200 in the embodiment. The optical disc 200 has a laser light incident side surface covered with a transparent protective layer. The optical disc 200 has a recording density determined according to the number of recording layers.
In this optical disk apparatus, 201 is an optical pickup, 202 is a laser light source, 203 is a collimating lens, 204 is a polarization beam splitter, 205 is a quarter wave plate, 206 is a total reflection mirror, 207 is an objective lens, 208 is an actuator, 209 Is a spherical aberration correction element, 210 is a cylindrical lens, 211 is a condenser lens, 212 is a photodetector, 213 is a spindle motor, 214 is a thread motor, 221 is a spindle motor drive circuit, 222 is an actuator drive circuit, and 223 is a thread motor. A drive circuit, 224 is a spherical aberration correction element drive circuit, 225 is a reproduction signal generation circuit, 226 is a wobble signal generation circuit, 227 is a servo signal generation circuit, 228 is a laser drive circuit, and 229 is a system control circuit.

  According to the configuration of the optical pickup 201, the light beam emitted from the laser light source 202 is converted into a parallel light beam by the collimator lens 203, passes through the polarization beam splitter 204, and is converted into circularly polarized light by the quarter wavelength plate 205. Is done. The circularly polarized light is added with a predetermined spherical aberration by the spherical aberration correction element 209, then reflected on the total reflection mirror 206 and guided to the objective lens 207. The objective lens 207 forms a light spot on the information recording layer of the optical disc 200 corresponding to the incident light beam.

  On the other hand, the reflected light beam from the optical disc 200 passes through the objective lens 207, the total reflection mirror 206, the spherical aberration correction element 209, and the quarter wavelength plate 205 again and is reflected by the polarization beam splitter 204. Then, the reflected light beam passes through the cylindrical lens 210 and is condensed on the photodetector 212 by the condenser lens 211.

  The electric signal output from the photodetector 212 is supplied to the reproduction signal generation circuit 225, the wobble signal generation circuit 226, and the servo signal generation circuit 227. The reproduction signal generation circuit 225 obtains a reproduction information signal recorded on the optical disc 200, the wobble signal generation circuit 226 generates a wobble signal corresponding to the wobbled track of the optical disc, and the servo signal generation circuit 226 generates a focus error. Various servo signals such as a signal, a tracking error signal, and a pull-in error signal corresponding to the amount of light reflected from the disk 200 are generated and output to the system control circuit 229.

  The system control circuit 229 has a function of controlling the entire optical disc apparatus. That is, the rotation control of the optical disc 200 mounted on the spindle motor 213 is performed via the spindle motor drive circuit 221, and the actuator 208 equipped with the objective lens 207 is driven via the actuator drive circuit 222 so that focus, tracking, etc. Servo control is performed, and the thread motor 214 is driven via the sled motor driving circuit 223 to control the transfer of the optical pickup 201 in the disk radial direction. Further, the optical pickup 201 is controlled via the spherical aberration correction element driving circuit 224. Detect and correct spherical aberration.

  Further, the system control circuit 229 stores therein a spindle motor rotation speed table corresponding to the number of disk layers in the circuit. When discriminating the number of disk layers, a drive signal corresponding to the table is sent to the spindle motor drive circuit 221 to control the spindle motor 213.

  The system control circuit 229 drives the laser light source 202 via the laser drive circuit 226 so that the light amount of the light spot condensed on the information recording layer of the optical disc 200 becomes a predetermined light amount.

  FIG. 2 shows an example of the flow of processing by the system control circuit 229 of the optical disk apparatus in this embodiment.

  In step S201 in the figure, the optical disc 200 is inserted into the optical disc apparatus. In step S202, it is determined whether the optical disc 200 is a CD, a DVD or a BD. If it is discriminated as a CD or DVD by the branching process depending on the disc type (S203), a spindle control process corresponding to the CD or DVD is performed (S204). If it is discriminated to be BD, the pickup 201 is moved to a radial position for discriminating the number of layers and performing focus pull-in by driving the stepping motor 214 (S205). In step S206, the number of layers of the inserted optical disk 200 is determined based on a focus error signal obtained by moving the objective lens 208 in a direction perpendicular to the optical disk 200 in a state where a laser corresponding to BD is emitted.

  FIG. 3 shows an example of a focus error signal detected when an optical disc having four recording layers is used. By moving the objective lens 207 in a direction perpendicular to the disk surface and scanning the focal position of the laser beam, a focus error signal generally called an S-shaped waveform is obtained. Since the S-shaped waveform is considered to be detected by the number of recording layers of the optical disk, the number of recording layers of the optical disk 200 inserted is determined from the number of S-shaped.

  In step S207, the target rotational speed Nt of the spindle motor corresponding to the number of layers of the optical disk 200 determined in step S206 is determined based on a disk rotational speed table prepared in advance in the system control circuit 229. Next, the spindle control mode is set to the FG control mode (S208), spindle control is started, and the optical disk is rotated (S209). Next, focus pull-in is performed, and focus control is started so that the light spot is focused on a predetermined recording layer (S210). The rotational speed of the optical disc 200 is monitored (S211). For example, when the wobble signal reaches a reproducible rotational speed within 10% of the target rotational speed, the mode is switched to the wobble control mode (S212). Through the above processing, spindle control corresponding to the type of disk and the recording density is performed.

  In the above process, in order to set the target rotation speed Nt according to the recording density, that is, the number of layers determined in advance in the layer number determination process S207 before the spindle control is started, it is necessary to change the target rotation speed in step S711 in FIG. Absent.

  Here, the radial position at which the focus is pulled in step S205 may be always pulled at the same radial position regardless of the type of the optical disk 200 to be inserted.

  Here, in the first embodiment, the type determination process of the optical disc 200 in step S202 may be performed simultaneously with the determination of the number of layers of the optical disc. The processing by the system control circuit 229 in this case is shown in FIG.

In FIG. 4, the optical disc 200 is inserted in step S401, and in step S402, the pickup 201 is moved to a radial position where disc type determination, layer number discrimination, and focus pull-in are performed. In step S403, the laser corresponding to the BD is emitted. Next, the objective lens 208 is moved in the direction perpendicular to the optical disc 200 (S404), and the amplitude of the obtained pull-in error signal is compared with a predetermined determination level _VBD (S405). When the pull-in error signal is equal to or higher than the determination level V _BD (Yes), the number of layers of the inserted optical disc 200 is determined based on the number of times the pull-in error signal exceeds the determination level V _BD (S406). In step S407, a target rotational speed Nt corresponding to the number of layers of the optical disc 200 determined in step S406 is determined based on a spindle motor rotational speed table prepared in advance in the system control circuit 229. Next, the spindle control mode is set to the FG control mode (S408), the spindle control is started, and the optical disk is rotated (S409). Next, focus pull-in is performed, and focus control is started so that the light spot is condensed on a predetermined recording layer (S410). The rotational speed of the optical disc 200 is monitored (S411). For example, when the rotational speed of the wobble signal reaches a reproducible rotational speed within 10% of the target rotational speed, the wobble control mode is switched (412).

In step S405, if the pull-in error signal is equal to or lower than the determination level V _BD (No), the laser corresponding to BD is extinguished and the laser corresponding to DVD is emitted (S413). Next, the objective lens 208 is moved in the direction perpendicular to the optical disc 200 (S414), and the amplitude of the obtained pull-in error signal is compared with a predetermined determination level V _DVD (S415). If the pull-in error signal is equal to or higher than the determination level V _DVD (Yes), spindle control processing corresponding to DVD is performed (S416).

In step S415, when the pull-in error signal is equal to or lower than the determination level V _DVD (No), the laser corresponding to the DVD is extinguished and the laser corresponding to the CD is emitted (S417). Next, the objective lens 208 is moved in the direction perpendicular to the optical disc 200 (S418), and the amplitude of the obtained pull-in error signal is compared with a predetermined determination level V _CD (S419). If the pull-in error signal is equal to or higher than the determination level V _CD (Yes), spindle control processing corresponding to CD is performed (S420).

In step S419, when the pull-in error signal is equal to or lower than the determination level V _CD (No), it is determined that the optical disk is not compatible or that there is no optical disk.

  In the present embodiment, in step S206 of the layer number determination process of the optical disc 200 in the first embodiment, a pull-in error signal that is the total light amount received by the photodetector 214 is used as the layer number determination means instead of the focus error signal. The optical disc 200 in the present embodiment is assumed to have the same configuration as that of the first embodiment.

  Since the amount of reflected light from each recording layer increases when the objective lens 207 is positioned near the focal point, when the objective lens 207 is moved in the focus direction in step S404, the objective lens 207 is moved as shown in FIG. The amplitude of the partial pull-in error signal increases at a timing positioned near the focal point of each recording layer, and is detected as a convex waveform.

FIG. 5 shows a pull-in error signal detected when an optical disc having four recording layers is used as an example. The convex waveform is considered to be detected by the number of recording layers of the optical disc, and the number of recording layers of the optical disc 200 inserted is determined from the number of times that the predetermined waveform exceeds a predetermined determination level _VBD .

  In this embodiment, the corresponding laser is emitted in the order of BD, DVD, and CD to discriminate the disc type. However, other types of discs may be used.

  In the above two embodiments, the method using the focus error signal and the pull-in error signal has been described. However, the accuracy can be further improved by using these two signals together. Further, a signal that can determine the number of layers other than the two signals may be used. In this embodiment, the number of layers is determined by using the focus error signal and the pull-in error signal in the recording layer. However, the number of layers is also determined including the focus error signal and the pull-in error signal detected on the surface of the disc. You may make it do.

  In addition, this invention is not limited to an above-described Example, Various modifications are included. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. In addition, a part of the configuration of a certain embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of a certain embodiment.

DESCRIPTION OF SYMBOLS 200 ... Optical disk, 201 ... Optical pick-up, 202 ... Laser light source, 203 ... Collimating lens, 204 ... Polarizing beam splitter, 205 ... 1/4 wavelength plate, 206 ... Total reflection mirror, 207 ... Objective lens, 208 ... Actuator, 209 ... Spherical aberration correction element, 210... Cylindrical lens, 211.
Condensing lens, 212... Photodetector, 213... Spindle motor, 214... Thread motor, 221... Spindle motor drive circuit, 222... Actuator drive circuit, 223. ... reproduction signal generation circuit, 226 ... wobble signal generation circuit, 227 ... servo signal generation circuit, 228 ... laser drive circuit, 229 ... system control circuit

Claims (8)

  In an optical disc apparatus that records or reproduces information on a multilayer optical disc having a plurality of recording surfaces and having different recording densities depending on the number of recording surfaces, a spindle motor that rotates the multilayer optical disc, and a rotation speed of the spindle motor A rotation speed control means for controlling the laser beam, an objective lens for condensing laser light, an actuator for driving the objective lens, a drive signal output means for outputting a drive signal to the actuator, and the drive signal output means. An optical disc comprising a control means and a photodetector for receiving reflected light of a light spot on the disc, wherein the rotational speed of the spindle motor is set according to the number of layers determined by discriminating the number of layers after the optical disc is inserted apparatus.   2. The optical disk apparatus according to claim 1, wherein the determination of the number of layers after the optical disk is inserted determines the total number of layers based on a focus error signal.   2. The optical disc apparatus according to claim 1, wherein the discriminating the number of layers after inserting the optical disc discriminates the total number of layers based on a pull-in error signal.   2. The optical disk apparatus according to claim 1, wherein the number of layers and the type of the optical disk are determined at the same radial position.   2. The optical disk apparatus according to claim 1, wherein a rotation speed of the spindle motor corresponding to the number of layers of the optical disk is determined based on a spindle motor rotation speed table prepared in advance.   2. The optical disk apparatus according to claim 1, wherein the optical disk apparatus is swept in a focus direction in a state where a laser is emitted before rotating the inserted optical disk.   An optical disk apparatus for recording or reproducing information on a multilayer optical disk having a plurality of recording surfaces, a spindle motor that rotates the multilayer optical disk, a laser light source, and a laser beam emitted from the laser light source Objective lens, an actuator for driving the objective lens, drive signal output means for outputting a drive signal to the actuator, control means for controlling the drive signal output means, and reflected light of the light spot on the disk A light detector is provided, and the objective lens is driven in the focus direction by the actuator while emitting the laser light without rotating the optical disk, and then the spindle motor is set according to the number of layers on the recording surface of the multilayer optical disk. Light that rotates at a rotation speed set by Disk apparatus. A spindle control method for an optical disc apparatus for recording or reproducing information on a multilayer optical disc having a plurality of recording surfaces,
A spindle motor that rotates a multilayer optical disk having a plurality of recording surfaces and having different recording densities depending on the number of recording surfaces, a control unit that controls the rotation speed of the spindle motor, a laser light source, and light emitted from the laser light source. An objective lens for condensing the laser beam, an actuator for driving the objective lens, a drive signal output means for outputting a drive signal to the actuator, a control means for controlling the drive signal output means, and the multilayer disk In the optical disc apparatus provided with a photodetector for receiving the reflected light of the light spot, the objective lens is driven in the focus direction by the actuator while emitting the laser light without rotating the multilayer optical disc, The spindle motor is adapted to the number of recording surfaces of the multilayer optical disc. Spindle control method characterized by a rotational speed to be set, rotate Te.

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