JP2007066484A - Control method of optical disk apparatus, and optical disk apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control method of an optical disk apparatus, and an optical disk apparatus in which probability causing miss tracking can be reduced. <P>SOLUTION: At least a first laser beam 104 and a second laser beam 105 are emitted, An arbitrary point on a surface of an optical disk 1 is passed through a spot region 102 based on the second laser beam and a spot region 103 based on the first laser beam in this order, when the arbitrary point is entered to the spot region 102 based on the second laser beam, detection of existence of a defect 101 in the arbitrary point is performed, and when it is judged that the defect 101 exists, until the defect 101 is finished to pass through the spot region 103 based on the first laser beam, at least one of actions that control of a first objective lens 4 emitting the first laser beam 104 is interrupted, and that light quantity of the first laser beam 104 is reduced, is performed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method of controlling an optical disk device and at least one optical disk device when information is recorded on or reproduced from an optical disk.

  Optical disk devices are actively being developed for various applications and high performance. In particular, recording density has recently been increased due to the use of a large-capacity optical disc such as a Blu-ray disc, and the optical disc apparatus has been greatly affected by defects such as scratches and dirt on the optical disc. Therefore, an optical disc apparatus that is less susceptible to defects has been desired.

  Here, the configuration of the optical pickup control system in the conventional optical disc apparatus will be described with reference to the drawings.

  FIG. 12 is a block diagram of an optical pickup control system in a conventional optical disc apparatus. In FIG. 12, 1 is an optical disk, 502 is a spindle motor, 503 is a pickup module, 504 is an objective lens, 506 is a carriage, 507 is a feed unit, 508 is a reproduction signal generation means, 509 is a reproduction signal processing means, and 511 is a control signal. Generation means 512 is servo control means, and 513 is motor drive means.

  The operation of the optical pickup control system in the conventional optical disc apparatus configured as described above will be described.

  The pickup module 503 includes a spindle motor 502 that rotates the optical disc 1, an objective lens 504 that records or reproduces information on the optical disc 1 using laser light, and a carriage 506 on which the objective lens 504 is mounted. 1 and a feed portion 507 for moving in the radial direction.

  The control signal generation means 511 generates a focus error signal and a tracking error signal based on a signal output from a split sensor (not shown) inside the optical pickup in the carriage 506 provided inside the pickup module 503, Output to servo control means 512.

  The servo control means 512 includes an ON / OFF circuit, an arithmetic circuit, a filter circuit, an amplifier circuit, and the like, and motor driving means based on the focus error signal and the tracking error signal so that the laser light follows the information track of the optical disk 1. Focus / tracking control of the objective lens 504 is performed via 513.

  The feed unit 507 includes a feed motor, a gear, a screw shaft, and the like. When the feed motor is rotated, the carriage 506 moves, and feed motor pulses are periodically output from the feed motor.

  Further, the reproduction signal generation means 508 generates a reproduction signal based on the electrical signal from the pickup module 503, and the reproduction signal processing means 509 performs signal processing such as synchronization / correction to perform data reproduction.

  When media with a thin substrate such as a Blu-ray disc is used for the optical disc 1, tracking servo and reading performance tend to become unstable due to defects such as dust, scratches and dirt on the surface of the optical disc 1, and the conventional main beam defect Detection has become inadequate.

As a prior art related to prevention of mistracking, an optical tracking device capable of preventing mistracking due to factors such as scratches occurring on an optical recording medium is described in Patent Document 1.
JP-A-62-121936

  (Patent Document 1) uses a means that emits a plurality of lights as a light source, scans spots A and B back and forth within the same tracking guide on the optical recording medium, and makes mistakes such as scratches on the optical recording medium. Even if there is a tracking factor, it is immediately detected and correct information is read using a normal tracking signal obtained at either spot A or spot B to prevent mistracking.

  However, in the above-described conventional configuration, when the cause of mistracking such as a scratch exceeds the distance between the spots A and B, a normal tracking signal cannot be obtained for both the spots A and B. There is a problem that the effect of preventing mistracking by switching the tracking signal cannot be expected.

  The present invention solves such a conventional problem, and makes it less susceptible to defects in tracking control even when defects such as dust, scratches and dirt on the optical disk surface are relatively large. An object of the present invention is to provide an optical disk device control method and an optical disk device that can reduce the probability of mistracking.

  The present invention has been made to solve the above-described problems, and at least a first laser beam and a second laser beam are emitted, and an arbitrary point on the optical disk surface is a spot based on the second laser beam. When an arbitrary point enters a spot region based on the second laser beam, the presence / absence of the defect at the arbitrary point is detected, and there is a defect. If it is determined that the control of the objective lens that emits the first laser light is interrupted until the defect is completely passed through the spot region based on the first laser light, or the first laser light is The method of controlling the optical disc apparatus is characterized in that at least one of the light quantity reduction is performed.

  Further, a rotation driving means for rotating the optical disk, a first objective lens for irradiating the optical disk with the first laser light, a second objective lens for irradiating the optical disk with the second laser light, and the optical disk A light receiving means for receiving reflected light from the light, a control signal generating means for generating an RF signal based on a signal received by the light receiving means, and an optical disc by measuring at least one of an RF signal amplitude or a reflected light level based on the reflected light A defect detection means for detecting the presence / absence of a defect on the surface, and a control unit for performing tracking control on the optical disc, wherein the control unit emits at least a first laser beam and a second laser beam, An arbitrary point is passed in the order of the spot area based on the second laser beam and the spot area based on the first laser beam. When entering the spot area based on the laser beam 2 and detecting the presence / absence of a defect at an arbitrary point, if it is determined that there is a defect, the defect has passed the spot area based on the first laser beam. In the meantime, the control of the objective lens that emits the first laser light is interrupted, or at least one of reducing the light amount of the first laser light is performed.

  In addition, a rotation driving means for rotating the optical disk, a light source for emitting laser light to the optical disk, a hologram for separating the laser light into at least the first laser light and the second laser light, and light reflected from the optical disk are received. Optical disc surface by measuring at least one of the RF amplitude or the reflected light level based on the reflected light of the second laser beam, and a control signal generating means for generating an RF signal based on the signal received by the light receiving means. Defect detection means for detecting the presence / absence of the upper defect and a control unit for performing tracking control on the optical disc, the control unit assigns an arbitrary point on the optical disc surface to the spot region based on the second laser beam, the first When passing an arbitrary spot in the spot area based on the second laser beam through the spot area based on the laser beam of Detecting the presence / absence of a defect at an arbitrary point, and if it is determined that there is a defect, control of the objective lens that emits laser light until the defect passes through the spot area based on the first laser light Is interrupted.

  Further, the control of the objective lens that records and reproduces information on the Blu-ray disc is controlled based on information obtained from the objective lens other than that that records and reproduces on the Blu-ray disc. This is a control method of the optical disc apparatus.

  Furthermore, a rotation drive means for rotating the Blu-ray disc, a first objective lens for recording or reproducing information on the Blu-ray disc, and a first objective lens for recording or reproducing information on a medium other than the Blu-ray disc. 2 objective lens, light receiving means for receiving reflected light from a Blu-ray disc, control signal generating means for generating an RF signal based on a signal received by the light receiving means, and an RF signal amplitude or reflected light level based on the reflected light A defect detection means for detecting the presence / absence of a defect on the surface of the Blu-ray disc and a control unit for performing tracking control on the Blu-ray disc, wherein the control unit controls the first objective lens, Light controlled based on information obtained from the second objective lens It is a disk apparatus.

  With the above configuration, the present invention passes an arbitrary point on the optical disk surface in the order of the spot region based on the second laser beam and the spot region based on the first laser beam, and the arbitrary point is based on the second laser beam. Since the presence or absence of a defect at an arbitrary point is detected when entering the spot area, it is possible to detect a harmful defect in advance when recording or reproducing information with the first laser beam.

  When it is determined that there is a defect by detecting the presence / absence of the defect, the control of the objective lens that emits the first laser light is interrupted until the defect has passed through the spot area based on the first laser light. Or by reducing the amount of the first laser beam, it is possible to avoid the off-tracking caused by using the reflected light whose reliability of information is reduced due to the influence of the defect. Even when defects such as dirt and dirt are relatively large, the influence of the defects can be minimized, and the probability of mistracking can be reduced.

  Therefore, it becomes possible to make it less susceptible to defects in tracking control, and it is possible to realize an optical disk device control method and an optical disk device that can reduce the probability of mistracking.

  According to the first aspect of the present invention, at least a first laser beam and a second laser beam are emitted, an arbitrary point on the optical disk surface is a spot region based on the second laser beam, and a spot based on the first laser beam. When an arbitrary point passes through the region and enters a spot region based on the second laser beam, the presence / absence of the defect at the arbitrary point is detected, and if it is determined that there is a defect, the defect is detected. Until the passage through the spot region based on the first laser light is completed, at least one of the control of the objective lens that emits the first laser light is interrupted or the light amount of the first laser light is reduced A control method of an optical disc apparatus characterized by being performed. When an arbitrary point on the optical disk surface passes in the order of the spot area based on the second laser light and the spot area based on the first laser light, and the arbitrary point enters the spot area based on the second laser light Since the presence / absence of a defect at an arbitrary point is detected, a harmful defect can be detected in advance when information is recorded or reproduced with the first laser beam. When it is determined that there is a defect by detecting the presence / absence of the defect, the control of the objective lens that emits the first laser light is interrupted until the defect has passed through the spot area based on the first laser light. Or at least one of the reduction of the light amount of the first laser light can be performed to avoid the off-tracking caused by using the reflected light whose reliability of information is reduced due to the influence of the defect. Even when defects such as dust, scratches and dirt on the optical disk are relatively large, the influence of the defects can be minimized, and the probability of occurrence of mistracking can be reduced. Therefore, it is possible to make it difficult to be affected by defects in tracking control, and it is possible to realize a method for controlling an optical disc apparatus that can reduce the probability of mistracking.

  The invention according to claim 2 is the method of controlling an optical disc apparatus according to claim 1, wherein the wavelengths of the first laser beam and the second laser beam are different. In the optical disc apparatus for emitting laser beams having a plurality of different wavelengths, which can be used for a plurality of types of discs such as a Blu-ray disc, a DVD, a CD, etc., by changing the wavelengths of the first laser beam and the second laser beam. There is no need to provide light emitting means for emitting laser light dedicated to defect detection.

  The invention according to claim 3 is characterized in that the control of the objective lens that emits the first laser light is interrupted immediately before the defect enters the spot region based on the first laser light. A method for controlling an optical disc device according to any one of the preceding claims. The control of the objective lens emitting the first laser light is interrupted immediately before the defect enters the spot region based on the first laser light, thereby maximizing the probability that mistracking will occur after the control of the objective lens is interrupted. It is possible to reduce it to the limit.

  According to a fourth aspect of the present invention, in any one of the first and second aspects, the light amount of the first laser beam is lowered immediately before the defect enters the spot region based on the first laser beam. It is a control method of the described optical disk apparatus. By reducing the light amount of the first laser light immediately before the defect enters the spot region based on the first laser light, the probability that mistracking will occur after the light amount of the first laser light is reduced is maximized. It becomes possible to reduce.

  The invention according to claim 5 is characterized in that the defect detection is judged as having a defect when at least one of the RF signal amplitude or the reflected light level based on the reflected light of the second laser light falls below a predetermined threshold value. 5. A method for controlling an optical disc apparatus according to claim 1. Defect detection can be performed with high accuracy by determining that there is a defect when at least one of the RF signal amplitude or the reflected light level based on the reflected light of the second laser light falls below a predetermined threshold. .

  The invention according to claim 6 is the method of controlling an optical disc apparatus according to any one of claims 1 to 5, wherein the first laser beam and the second laser beam are emitted simultaneously. Since the first laser beam and the second laser beam are emitted at the same time, the defect detection time can be shortened.

  The invention according to claim 7 is characterized in that a wavelength for Blu-ray disc is used for the first laser light, and a wavelength for DVD or CD is used for the second laser light. A method for controlling an optical disc device according to any one of the preceding claims. An optical disc on which a plurality of discs such as a Blu-ray disc, a DVD, and a CD can be used by using a wavelength for a Blu-ray disc for the first laser beam and a wavelength for DVD or CD for the second laser beam. In the apparatus, when recording and / or reproducing information on a Blu-ray disc, the light emitting means for emitting laser light used for recording / reproducing for DVD or CD and the light emitting means for emitting laser light for detecting defect are shared. Therefore, there is no need to newly provide a light emitting means for emitting a laser beam dedicated to defect detection.

  According to an eighth aspect of the present invention, there is provided a rotary driving means for rotating the optical disc, a first objective lens for irradiating the optical disc with the first laser beam, and a second for irradiating the optical disc with the second laser beam. Objective lens, light receiving means for receiving reflected light from the optical disk, control signal generating means for generating an RF signal based on a signal received by the light receiving means, and at least an RF signal amplitude or reflected light level based on the reflected light Defect detecting means for measuring one of them and detecting the presence / absence of a defect on the optical disc surface and a control unit for performing tracking control on the optical disc are provided, and the control unit outputs at least the first laser beam and the second laser beam. Emitting, passing an arbitrary point on the optical disk surface in the order of the spot area based on the second laser beam, the spot area based on the first laser beam, When a desired point enters the spot region based on the second laser beam, the presence / absence of a defect is detected at an arbitrary point. If it is determined that there is a defect, the defect is based on the first laser beam. An optical disc apparatus characterized in that the control of the objective lens that emits the first laser beam is interrupted or at least one of the light amount of the first laser beam is reduced until the passage through the spot region is completed. is there. The control unit emits at least a first laser beam and a second laser beam, and passes an arbitrary point on the optical disk surface in the order of a spot region based on the second laser beam and a spot region based on the first laser beam. When an arbitrary point enters the spot area based on the second laser beam, it is harmful when recording or reproducing information with the first laser beam by detecting the presence or absence of a defect at the arbitrary point. Defects can be detected in advance. When it is determined that there is a defect by detecting the presence or absence of the defect, the control of the objective lens that emits the first laser beam is interrupted until the defect has passed through the spot region based on the first laser beam. In addition, by performing at least one of reducing the light amount of the first laser light, it is possible to avoid the off-tracking caused by using the reflected light whose reliability of information is reduced due to the influence of the defect. Even when defects such as dust, scratches and dirt are relatively large, it is possible to minimize the influence of the defects and reduce the probability of mistracking. Therefore, it is possible to make it difficult to be affected by defects in tracking control, and it is possible to realize an optical disc apparatus that can reduce the probability of mistracking.

  The invention according to claim 9 is the optical disc apparatus according to claim 8, wherein the first laser beam and the second laser beam have different wavelengths. In the optical disc apparatus for emitting laser beams having a plurality of different wavelengths, which can be used for a plurality of types of discs such as a Blu-ray disc, a DVD, a CD, etc., by changing the wavelengths of the first laser beam and the second laser beam. There is no need to provide light emitting means for emitting laser light dedicated to defect detection.

  The invention according to claim 10 is characterized in that the control of the objective lens emitting the first laser beam is interrupted immediately before the defect enters the spot region based on the first laser beam. An optical disc apparatus according to any one of the above items. The control of the objective lens emitting the first laser light is interrupted immediately before the defect enters the spot region based on the first laser light, thereby maximizing the probability that mistracking will occur after the control of the objective lens is interrupted. It is possible to reduce it to the limit.

  The invention according to claim 11 is characterized in that the light quantity of the first laser beam is lowered immediately before the defect enters the spot region based on the first laser beam. The optical disk device described. It is possible to reduce the probability of mistracking to the maximum after the amount of the first laser light is reduced.

  The invention according to claim 12 is characterized in that a line connecting the center in the radial direction of the first objective lens and the center in the radial direction of the second objective lens is perpendicular to the radial direction of the mounted optical disk. An optical disc apparatus according to any one of claims 8 and 9. Defects can be detected with high accuracy by the fact that the line connecting the center in the radial direction of the first objective lens and the center in the radial direction of the second objective lens is perpendicular to the radial direction of the mounted optical disk. it can.

  In the invention described in claim 13, when the focal length of the first objective lens is WDA and the focal length of the second objective lens is WDB, the distance between the first objective lens and the second objective lens in the focus direction is 10. The optical disk apparatus according to claim 8, wherein the optical disk apparatus is a WDB-WDA. When the focal length of the first objective lens is WDA and the focal length of the second objective lens is WDB, the distance in the focus direction between the first objective lens and the second objective lens is WDB-WDA. Defects that are harmful when information is recorded or reproduced using the first objective lens can be accurately detected by the second laser light emitted from the second objective lens.

  According to a fourteenth aspect of the present invention, there is provided a rotation driving means for rotating an optical disk, a light source for emitting laser light to the optical disk, a hologram for separating the laser light into at least first laser light and second laser light, and an optical disk. A light receiving means for receiving reflected light from the light, a control signal generating means for generating an RF signal based on a signal received by the light receiving means, and at least one of an RF amplitude or a reflected light level based on the reflected light of the second laser light A defect detection means for measuring the presence or absence of a defect on the optical disk surface and a control section for performing tracking control on the optical disk, and the control section converts an arbitrary point on the optical disk surface to the second laser beam. A spot region based on the first laser beam, and a spot region based on the second laser beam. When a defect is detected at an arbitrary point when entering the target area, and it is determined that there is a defect, the laser is used until the defect has passed through the spot area based on the first laser beam. An optical disc apparatus characterized by interrupting control of an objective lens that emits light. The control unit passes an arbitrary point on the optical disc surface in the order of the spot area based on the second laser light and the spot area based on the first laser light, and the arbitrary point becomes a spot area based on the second laser light. When entering, by detecting the presence / absence of a defect at an arbitrary point, it becomes possible to detect a harmful defect in advance when recording or reproducing information with the first laser beam. Then, when it is determined that there is a defect by detecting the presence or absence of the defect, the control of the objective lens that emits the laser light is interrupted until the defect has passed through the spot region based on the first laser light, It is possible to avoid out-of-tracking caused by reflected light whose reliability of information has deteriorated due to the influence of the defect, and even if the defect such as dust, scratches and dirt on the optical disk is relatively large, The influence can be minimized, and the probability of mistracking can be reduced. Therefore, it is possible to make it difficult to be affected by defects in tracking control, and it is possible to realize an optical disc apparatus that can reduce the probability of mistracking.

  The invention according to claim 15 is perpendicular to the radial direction of the optical disc on which a line connecting the center of the spot region formed by the first laser beam and the center of the spot region formed by the second laser beam is mounted. 15. The optical disc apparatus according to claim 14, wherein The defect detection is accurate because the line connecting the center of the spot region formed by the first laser beam and the center of the spot region formed by the second laser beam is perpendicular to the radial direction of the optical disc mounted. Can be done well.

  According to the sixteenth aspect of the present invention, the control of the objective lens that performs at least one of recording and reproduction of information on the Blu-ray disc is based on information obtained from the objective lens other than performing at least one of recording and reproduction on the Blu-ray disc. A control method for an optical disc apparatus, wherein the optical disc apparatus is controlled. The control of an objective lens that records and / or reproduces information on / from a Blu-ray disc is controlled based on information obtained from an objective lens other than that that records and / or reproduces information on / from a Blu-ray disc. Even when there is a defect on the surface of the Blu-ray disc when performing at least one of recording or reproduction of information, the information can be obtained from an objective lens other than performing at least one of recording or reproduction on the Blu-ray disc, The effects of defects can be minimized. Therefore, it is possible to make it difficult to be affected by defects in tracking control, and it is possible to realize a method for controlling an optical disc apparatus that can reduce the probability of mistracking.

  According to a seventeenth aspect of the present invention, there is provided a rotation driving means for rotating a Blu-ray disc, a first objective lens for recording or reproducing information on the Blu-ray disc, and recording or reproducing information on a medium other than the Blu-ray disc. A second objective lens that performs at least one; a light receiving unit that receives reflected light from the Blu-ray disc; a control signal generating unit that generates an RF signal based on a signal received by the light receiving unit; and an RF signal based on the reflected light Defect detection means for measuring the presence or absence of a defect on the surface of the Blu-ray disc by measuring at least one of the amplitude and the reflected light level, and a control unit for performing tracking control on the Blu-ray disc, the control unit comprising the first objective The control of the lens based on the information obtained from the second objective lens. An optical disk apparatus according to symptoms. The control unit controls the first objective lens based on the information obtained from the second objective lens, so that at least one of recording and reproduction of information on the Blu-ray disc is performed by the first objective lens. At this time, even if there is a defect on the surface of the Blu-ray disc, the information can be obtained from the second objective lens, and the influence of the defect can be minimized. Therefore, it is possible to make it difficult to be affected by defects in tracking control, and it is possible to realize an optical disc apparatus that can reduce the probability of mistracking.

(Embodiment 1)
Embodiment 1 of the present invention will be described below with reference to the drawings.

  FIG. 1 is a block diagram of an optical pickup control system of the optical disc apparatus according to Embodiment 1 of the present invention. In FIG. 1, 1 is an optical disk, 2 is a spindle motor, 3 is a pickup module, 4 is a first objective lens, 5 is a second objective lens, 6 is a carriage, 6a is a first light receiving means, and 6b is a second light receiving means. , 7 is a feed signal generation means, 9 is a reproduction signal processing means, 10 is a defect detection means, 11 is a control signal generation means, 12 is a servo control means, and 13 is a motor drive means.

  The operation of the optical pickup control system of the optical disc apparatus configured as above according to Embodiment 1 of the present invention will be described.

  The pickup module 3 includes a spindle motor 2 that rotates the optical disc 1, a first objective lens 4 that emits a first laser beam that performs at least one of recording and reproduction of information on the optical disc 1, and a first objective lens 4. The carriage 6 is composed of a feed unit 7 for moving the mounted carriage 6 in the radial direction of the optical disc 1.

  The control signal generation unit 11 is configured to generate an RF signal, a focus error signal, a tracking error, or the like based on a signal output obtained by the first light receiving unit 6a provided in the carriage 6 receiving the reflected light of the first laser beam. A signal is generated and output to the servo control means 12.

  The servo control means 12 is composed of an ON / OFF circuit, an arithmetic circuit, a filter circuit, an amplifier circuit, and the like, and motor driving means based on the focus error signal and the tracking error signal so that the laser light follows the information track of the optical disk 1. The first objective lens 4 is focus / tracked through 13.

  The feed unit 7 includes a feed motor, a gear, a screw shaft, and the like. The carriage 6 is moved by rotating the feed motor, and feed motor pulses are periodically output from the feed motor.

  The reproduction signal generation means 8 generates a reproduction signal based on the electric signal from the pickup module 3, and the reproduction signal processing means 9 performs signal processing such as synchronization / correction to perform data reproduction.

  The pickup module 3 is provided with a second objective lens 5 in addition to the first objective lens 4 that emits a first laser beam that performs at least one of recording and reproduction of information. The second objective lens 5 emits a second laser beam for detecting defects such as dust, scratches and dirt on the optical disk 1. Then, an arbitrary point on the optical disk surface passes in the order of the spot region based on the second laser beam and the spot region based on the first laser beam, and the arbitrary point becomes a spot region based on the second laser beam. Upon entering, detection of the presence / absence of a defect at an arbitrary point is performed.

  In the first embodiment, the first laser beam and the second laser beam have different wavelengths, the wavelength for the Blu-ray disc is used for the first laser beam, and the DVD or CD is used for the second laser beam. The wavelength for was used. The first laser beam can perform at least one of recording and reproduction of information with respect to at least a Blu-ray disc, and the second laser beam can perform at least recording and reproduction of information with respect to at least an optical disk for DVD or CD. One can do it. By doing so, in the case of an optical disc apparatus that emits laser beams of a plurality of different wavelengths that can be used with a plurality of types of discs such as Blu-ray discs, DVDs, and CDs, a light emitting means that emits laser beams dedicated to defect detection is newly provided There is no need, and at least one of recording and reproduction of information on a Blu-ray disc, light emission means for emitting laser light used for recording and reproduction for DVD or CD and light emission for emitting laser light for defect detection The means can be shared, and there is no need to newly provide a light emitting means for emitting a laser beam dedicated to defect detection.

  The defect detection means 10 is used in defect detection on the surface of the optical disc 1 based on the level of signal output obtained by the second light receiving means 6b provided inside the carriage 6 receiving the reflected light of the second laser light. Judge whether there is a defect.

  The servo control unit 12 constitutes a control unit of the present invention, and the servo control unit 12 controls the entire servo unit configured in this way. Although detailed description and illustration are omitted, the servo control unit 12 includes at least a calculation processing device such as a CPU and MPU having a calculation function, and a storage unit such as a ROM and a RAM.

  When at least one of information recording or reproduction is performed by the first laser beam, for example, when at least one of information recording or reproduction is performed on the Blu-ray disc by the first laser beam, the second Preferably, laser light is emitted simultaneously to detect the presence or absence of a defect. By doing so, the defect detection step and the step of recording or reproducing information can be made the same step, and the time for defect detection can be shortened.

  In the first embodiment, the first laser beam and the second laser beam have different wavelengths, the wavelength for Blu-ray Disc is used for the first laser beam, and the DVD is used for the second laser beam. Alternatively, using the wavelength for CD, based on the level of the signal output obtained when the defect detection means 10 receives the reflected light of the second laser beam, the presence / absence of a defect in the defect detection on the optical disk 1 surface is determined, When at least one of information recording and reproduction is performed with the first laser beam, the second laser beam is emitted at the same time to detect the presence or absence of the defect, but the present invention is not limited to this. For example, the second laser light has a wavelength for a Blu-ray disc, the determination of the presence or absence of a defect uses an RF signal described later, and the first laser light and the second laser light cannot be emitted simultaneously. It may be the case.

  Considering the accuracy of defect detection, the time of defect detection, and the number of components, defect detection is performed using the wavelength for Blu-ray Disc as the first laser beam and the wavelength for DVD or CD as the second laser beam. Based on the level of the signal output obtained by the means 10 receiving the reflected light of the second laser beam, the presence / absence of a defect in the defect detection on the surface of the optical disc 1 is determined, and information recording or recording with the first laser beam is performed. When at least one of the reproductions is performed, it is preferable that the second laser beam is emitted simultaneously to detect the presence or absence of the defect.

  Next, the relationship between the spot area based on the first laser beam and the spot area based on the second laser beam and the defect position on the optical disk surface will be described.

  FIG. 2 is a diagram showing the relationship between the spot area on the optical disk surface and the defect position in the first embodiment of the present invention. FIG. 2A is a diagram showing the positional relationship between the first objective lens, the second objective lens, and the optical disk, and FIG. 2B shows the spot region based on the first laser beam and the second laser beam. It is a figure which shows the positional relationship of the spot area | region based and a defect. In FIG. 2, 4 is a first objective lens, 5 is a second objective lens, 6 is a carriage, 7 is a feed section, 101 is a defect, 102 is a spot region based on the second laser beam, and 103 is a first objective lens. A spot region based on the laser beam, 104 is a first laser beam, and 105 is a second laser beam.

  In the first objective lens 4 and the second objective lens 5, arbitrary points on the surface of the optical disc 1 pass in the order of the spot region 102 based on the second laser light and the spot region 103 based on the first laser light. Are arranged as follows. For example, when the rotation direction of the optical disk 1 is shown in FIG. 2, the second objective lens 5 and the first objective lens 4 are arranged in this order from the left. When the first objective lens 4 and the second objective lens 5 are arranged in this manner, if there is a defect 101 such as dust, scratches or dirt at any point on the surface of the optical disc 1, the second laser beam is first used. A spot region 102 based on the crosses the defect 101. Therefore, it is possible to detect a harmful defect in advance when recording or reproducing information with the first laser beam.

  Next, a defect detection method and tracking control interruption will be described.

  FIG. 3 is a diagram showing control signals in the first embodiment of the present invention. 3A is an addition signal obtained based on the second laser beam, and FIG. 3B is a flaw detection signal generated based on the addition signal shown in FIG. 3 (c) is an addition signal obtained based on the first laser beam, FIG. 3 (d) is a control signal for controlling the first objective lens, and FIG. 3 (e) is the first signal. This is a drive signal for driving the objective lens.

  As described with reference to FIG. 2, when a defect 101 such as dust, scratches, or dirt exists at an arbitrary point on the surface of the optical disc 1, the spot region 102 based on the second laser beam first traverses the defect 101. Therefore, the influence of the defect 101 during the operation of the optical disk apparatus first appears in the addition signal obtained based on the second laser beam 105 shown in FIG. 3A, and then the first laser beam shown in FIG. It appears in the addition signal obtained based on 104.

  The defect detection signal shown in FIG. 3B is generated by the defect detection means 10 based on the addition signal obtained from the second laser beam 105 shown in FIG. As a result, it is possible to calculate the beginning of the disturbance of the control signal (tracking error signal) for controlling the first objective lens 4 shown in FIG. 3D, which occurs after T1 seconds from the rise of the scratch detection signal. Further, the time T1 ′ from the fall of the flaw detection signal necessary for the disturbance of the control signal (tracking error signal) for controlling the first objective lens 4 shown in FIG. A case in which the spot diameter of the spot area 103 based on the laser beam 104 and the spot diameter of the spot area 102 based on the second laser beam 105 are calculated in advance, and an addition signal based on the first laser beam 104 May be calculated directly from.

  By these methods, a control signal (tracking) for controlling the first objective lens 4 shown in FIG. 3D, which occurs T1 seconds after the rising edge of the scratch detection signal and ends after T1 ′ seconds after the falling edge of the scratch detection signal. The error signal) can be calculated. Here, T1 is the delay time of passing through the scratch, that is, the difference between the time during which the defect 101 passes through the spot region 102 based on the second laser beam 105 and the time through which the defect 101 passes through the spot region 103 based on the first laser beam, The calculation method will be described later.

  Then, the control of the first objective lens 4 that emits the first laser beam 104 is performed during the period in which the disturbance of the control signal occurs, that is, until the defect 101 passes through the spot region 103 based on the first laser beam. 3 is generated by the servo control means 12 so as to be interrupted.

  Tracking control of the first objective lens 4 is interrupted until the defect 101 passes through the spot region 103 based on the first laser beam by the generated drive signal. The control of the first objective lens 4 that emits the first laser beam 104 here is interrupted immediately before the defect 101 enters the spot region 103 based on the first laser beam, and therefore after the tracking control is interrupted. It is possible to reduce the probability of mistracking to the maximum. In this state, the state immediately before the defect 101 starts to cross the spot region 103 based on the first laser beam is still following the target track of the first objective lens 4. This is because by interrupting the tracking control, the probability of the initial mistracking being interrupted can be reduced to the maximum.

  In the defect detection, the presence / absence of a defect is determined to be a defect when at least one of the RF signal amplitude or the reflected light level based on the reflected light of the second laser light falls below a predetermined threshold. This utilizes the phenomenon that the amount of reflected light based on the second laser beam 105 always decreases when the spot region 102 based on the second laser beam crosses the defect 101. Here, the detection of the minimal defect 101 that hardly affects the recording or reproduction of information by the first laser beam 104 is eliminated, or a determination error caused by noise on the operation circuit is avoided. Considering this, the accuracy of the defect 101 detection can be improved.

  In the first embodiment, the control of the first objective lens 4 that emits the first laser beam 104 is interrupted immediately before the defect 101 enters the spot region 103 based on the first laser beam. However, the present invention is not limited to this. For example, the tracking control of the first objective lens 4 may be interrupted immediately after the defect 101 passes through the soot region 102 based on the second laser beam. Considering the probability of mistracking after the tracking control is interrupted, the first objective lens 4 that emits the first laser beam 104 is controlled by the spot region 103 in which the defect 101 is based on the first laser beam 104. It is preferable to be interrupted immediately before entering.

  In the first embodiment, the determination of the presence / absence of the defect in the defect detection is performed when at least one of the RF signal amplitude or the reflected light level based on the reflected light of the second laser beam 105 falls below a predetermined threshold. Although it was decided that there was, it is not limited to this. Considering the accuracy of defect detection, the determination of the presence / absence of defect in defect detection is that there is a defect when at least one of the RF signal amplitude or the reflected light level based on the reflected light of the second laser beam 105 falls below a predetermined threshold. It is preferable to judge.

  Next, the positional relationship among the optical disc, the first objective lens, and the second objective lens will be described.

  4 and 5 are diagrams showing a positional relationship among the optical disc, the first objective lens, and the second objective lens in the first embodiment of the present invention. 4 is a cross-sectional view of the optical disc and the carriage, and FIG. 5 is a plan view of the carriage as seen from the optical disc 1 side. 4 and 5, 1 is an optical disk, 4 is a first objective lens, 5 is a second objective lens, 6 is a carriage, 104 is a first laser beam, and 105 is a second laser beam.

  The first objective lens 4 and the second objective lens 5 are mounted on a carriage 6. If the focal length of the first objective lens 4 is WDA and the focal length of the second objective lens 5 is WDB, the first objective lens 4 and the second objective lens 5 are set to WDB. The objective lens 4 and the second objective lens 5 are provided at a position where the distance in the focus direction is WDB-WDA. By doing so, the defect 101 that is harmful when information is recorded or reproduced using the first objective lens 4 is accurately detected by the second laser beam 105 emitted from the second objective lens 5. can do. This is because the second laser beam 105 emitted from the second objective lens 5 can be focused on the surface of the optical disc 1, so that the spot diameter of the second laser beam 105 on the surface of the optical disc 1 is the defect 101. This is because the detection accuracy of the defect 101 is improved because the size becomes relatively small with respect to the size.

  A line A connecting the center in the radial direction of the first objective lens 4 that emits the first laser light 104 and the center in the radial direction of the second objective lens 5 that emits the second laser light 105 is attached. The optical disk 1 was arranged so as to be perpendicular to the radial direction. In this way, the defect 101 can pass through the spot region 103 based on the first laser beam 104 immediately after passing through the spot region 102 based on the second laser beam 105. It can be performed with high accuracy. If the optical disk on which the line A connecting the center in the radial direction of the first objective lens 4 emitting the first laser beam 104 and the center in the radial direction of the second objective lens 5 emitting the second laser beam 105 is mounted If not perpendicular to the radial direction of 1, the defect 101 cannot pass through the spot region 103 based on the first laser beam 104 immediately after passing through the spot region 102 based on the second laser beam 105. The scratch passage delay time T1 becomes longer and the accuracy of defect detection is lowered.

  In the first embodiment, if the focal length of the first objective lens 4 is WDA and the focal length of the second objective lens 5 is WDB, the first objective lens 4 and the second objective lens 5 are The position where the distance in the focus direction becomes WDB-WDA, the center in the radial direction of the first objective lens 4 that emits the first laser beam 104, and the radius of the second objective lens 5 that emits the second laser beam 105 Although the first objective lens 4 and the second objective lens 5 are provided at positions perpendicular to the radial direction of the optical disc 1 on which the line A connecting the centers in the direction is mounted, the present invention is not limited thereto. . Considering the accuracy of defect detection, if the focal length of the first objective lens 4 is WDA and the focal length of the second objective lens 5 is WDB, the first objective lens 4 and the second objective lens 5 are It is preferable to set the distance in the focus direction to WDB-WDA. Further, in consideration of a decrease in defect 101 detection accuracy due to an increase in the wound passage delay time T1, the radial center of the first objective lens 4 that emits the first laser beam 104 and the second laser beam. It is preferable that the line A connecting the centers in the radial direction of the second objective lens 5 that emits 105 is perpendicular to the radial direction of the mounted optical disk 1.

  Next, the scratch passage delay time T1 will be described with reference to FIG.

  The linear velocity of the second objective lens 5 (or the first objective lens 4) with respect to the rotating optical disk 1 is V (m / s), and the first objective lens 4 and the second objective lens 5 in the radial direction are used. When the center-to-center distance is L1 (m), the scratch passage delay time T1 described in FIG. 3 can be calculated by L1 / V (m). In this case, a line A connecting the center in the radial direction of the first objective lens 4 that emits the first laser beam 104 and the center in the radial direction of the second objective lens 5 that emits the second laser beam 105 is attached. Since it is assumed that the optical disk 1 is perpendicular to the radial direction of the optical disk 1, if the optical disk 1 is not perpendicular to the radial direction of the mounted optical disk 1, it is necessary to consider the angle of the mounted optical disk 1 with respect to the radial direction. . In addition, when the rotation speed of the spindle motor 2 that rotates the optical disk 1 is changed, it is necessary to consider the change in the rotation speed. In this way, the defect 101 that is harmful when information is recorded or reproduced using the first objective lens 4 is accurately detected by the second laser beam 105 emitted from the second objective lens 5. Can do.

  Next, procedures for defect detection and tracking control will be described.

  FIG. 6 is a flowchart showing defect detection and tracking control in the first embodiment of the present invention. Here, the first objective lens 4 is used for a Blu-ray disc and the second objective lens 5 is used for a DVD. However, the present invention is not limited to these. For example, the first objective lens 4 may be for a Blu-ray disc and the second objective lens 5 may be for a CD.

  When the optical disc 1 for the Blu-ray disc is mounted on the optical disc apparatus and an instruction to record or reproduce information is issued from the system for controlling the optical disc apparatus, the servo control means 12 receives the spindle motor via the motor drive means 13. 2, movement of the carriage 6, light emission of the first objective lens 4, and light emission of the second objective lens 5.

  When the spindle motor 2 reaches a predetermined number of revolutions and the carriage 6 moves to a predetermined point, the first laser beam 105 emitted from the second objective lens 5 is used to detect the defect 101 while performing the first detection. Information recording or reproduction is performed using the first laser beam 104 emitted from the objective lens 4. At this time, the second laser beam 105 reflected from the optical disc 1 is always received by the second light receiving means 6b, and the information is sent to the defect detecting means 10 and the control signal generating means 11.

  The defect detection means 10 determines that there is a defect 101 on the surface of the optical disc 1 when at least one of the RF signal amplitude based on the reflected light of the second laser beam 105 or the reflected light level falls below a predetermined threshold. Information is sent to the servo control means 12 (S1).

  In the servo control means 12, the linear velocity V (m / s) of the second objective lens 5 with respect to the rotating optical disc 1 and the distance between the lens centers in the radial direction of the first objective lens 4 and the second objective lens 5 are determined. The wound passage delay time T1 is calculated from L1 (m) (S2). Thereafter, tracking control is continued during the calculated wound passage delay time T1 (S3), and after the calculated wound passage delay time T1, the parameter change and tracking control based on the parameter change are performed (S4). At this time, it is necessary to consider the time required to calculate the flaw passage delay time T1 and the time required to switch the parameter. The parameter changes performed here are tracking servo hold, servo gain change, reproduction signal synchronization PLL hold, and data slicer hold.

  Next, when at least one of the RF signal amplitude or the reflected light level based on the reflected light of the second laser beam 105 recovers to a predetermined level and exceeds a predetermined threshold, the defect detection unit 10 sends information to the servo control unit 12. The servo controller 12 determines that the defect 101 on the surface of the optical disc 1 has passed through the spot region 102 based on the second laser beam 105 (S5).

  Then, during the wound passage delay time T1 ′ shown in FIG. 3, the tracking control of the first objective lens 4 is interrupted (S6), and the parameters changed earlier are restored to the original values after the passage of the wound passage delay time T1 ′ ( S7) The tracking control of the first objective lens 4 is resumed (S8). At this time, if the linear velocity of the second objective lens 5 with respect to the rotating optical disc 1 changes V (m / s), it is necessary to recalculate the wound passage delay time T1.

  As described above, an arbitrary point on the surface of the optical disc 1 passes through the spot region 102 based on the second laser beam 105 and the spot region 103 based on the first laser beam 104 in this order, and the arbitrary point passes through the second laser beam. When the spot region 102 based on the light 105 is entered, the presence or absence of the defect 101 at an arbitrary point is detected. Therefore, when the information is recorded or reproduced with the first laser beam 104, the harmful defect 101 is previously detected. It becomes possible to detect.

  If it is determined that the defect 101 is present by detecting the presence or absence of the defect 101, the first laser beam 104 is emitted until the defect 101 passes through the spot 103 based on the first laser beam 104. When the control of one objective lens 4 is interrupted, it is possible to avoid the off-tracking caused by using the reflected light whose reliability of information is lowered due to the influence of the defect 101, and it is possible to avoid dust or scratches on the optical disc 1. Even if the defect 101 such as dirt is relatively large, the influence of the defect 101 can be minimized, and the probability of mistracking can be reduced.

  Therefore, it is possible to make it less susceptible to the influence of the defect 101 in tracking control, and it is possible to realize an optical disc device control method and an optical disc device that can reduce the probability of mistracking.

  In the first embodiment, at least the first laser beam 104 and the second laser beam 105 are emitted, and an arbitrary point on the surface of the optical disc 1 is a spot region 102 based on the second laser beam 104, When an arbitrary point enters the spot region 102 based on the second laser beam 105 through the spot region 103 based on the first laser beam 105, detection of the presence or absence of the defect 101 at the arbitrary point is performed. If it is determined that the defect 101 is present, the control of the first objective lens 4 that emits the first laser beam 104 until the defect 101 passes through the spot region 103 based on the first laser beam 104 is completed. However, the presence or absence of the defect 101 at any point is detected and the diff is detected. If it is determined that the defect 101 exists, the same effect can be obtained by reducing the light amount of the first laser beam 104 until the defect 101 completes passing through the spot region 103 based on the first laser beam 104. Can be obtained. This is because the tracking information cannot be obtained with the reflected light from the optical disc 1 when the light amount of the first laser beam 104 decreases.

(Embodiment 2)
Embodiment 2 of the present invention will be described below with reference to the drawings.

  In the first embodiment, the case where the first laser beam is emitted from the first objective lens and the second laser beam is emitted from the second objective lens has been described, but in the second embodiment, the first laser beam is emitted from the first objective lens. The case where the first laser beam and the second laser beam are emitted from the same objective lens when the laser beam and the second laser beam have the same wavelength will be described.

  FIG. 7 is a block diagram of an optical pickup control system of the optical disc apparatus according to Embodiment 2 of the present invention. In FIG. 7, 1 is an optical disk, 2 is a spindle motor, 203 is a pickup module, 204 is an objective lens, 206 is a carriage, 206a is a first light receiving means, 206b is a second light receiving means, 7 is a feed section, and 8 is a feed section. Reproduction signal generation means, 9 is reproduction signal processing means, 10 is defect detection means, 11 is control signal generation means, 12 is servo control means, and 13 is motor drive means.

  The operation of the optical pickup control system of the optical disc apparatus configured as above according to Embodiment 2 of the present invention will be described.

  The pickup module 203 detects a spindle motor 2 that rotates the optical disc 1, a first laser beam that performs at least one of recording and reproduction of information on the optical disc 1, and defects such as dust, scratches, and dirt on the surface of the optical disc 1. The objective lens 204 for emitting the second laser beam for the purpose and the feed unit 7 for moving the carriage 206 on which the objective lens 204 is mounted in the radial direction of the optical disc 1 are configured.

  The control signal generation unit 11 generates an RF signal, a focus error signal, and a tracking error signal based on a signal output obtained by the first light receiving unit 206a in the carriage 206 receiving the reflected light of the first laser beam. And output to the reproduction signal processing means 9.

  The servo control means 12 is composed of an ON / OFF circuit, an arithmetic circuit, a filter circuit, an amplifier circuit, and the like, and motor driving means based on the focus error signal and tracking error signal so that the laser light follows the information track of the optical disc 1. The objective lens 204 is focus / tracked through 13.

  The feed unit 7 includes a feed motor, a gear, a screw shaft, and the like. The carriage 206 is moved by rotating the feed motor, and feed motor pulses are periodically output from the feed motor.

  The reproduction signal generation means 8 generates a reproduction signal based on the electrical signal from the pickup module 203, and the reproduction signal processing means 9 performs signal processing such as synchronization / correction to perform data reproduction.

  The defect detection means 10 determines whether or not there is a defect in defect detection on the surface of the optical disc 1 based on the level of the signal output obtained by the second light receiving means 206b in the carriage 206 receiving the reflected light of the second laser beam. Make a decision.

  The servo control unit 12 constitutes a control unit of the present invention, and the servo control unit 12 controls the entire servo unit configured in this way. Although detailed description and illustration are omitted, the servo control unit 12 includes at least a calculation processing device such as a CPU and MPU having a calculation function, and a storage unit such as a ROM and a RAM.

  Next, the configuration of the optical pickup according to the second embodiment of the present invention will be described.

  FIG. 8 shows an optical pickup according to the second embodiment of the present invention. In FIG. 8, 101 is a defect, 104 is a first laser beam, 105 is a second laser beam, 211 is a light source, 212 is a collimator lens, 213 is a hologram, 204 is an objective lens, 206a is a first light receiving means, Reference numeral 206b denotes a second light receiving means, and the optical path of the laser light is indicated by a broken line.

  The light source 211 contains a semiconductor laser for a Blu-ray disc. When the laser light emitted from the light source 211 passes through the collimator lens 212, at least two laser beams are provided by the hologram 213 provided on the surface of the collimator lens 212. The laser beam is separated as described above. In the second embodiment, the two laser beams are separated into three laser beams due to the characteristics of the hologram.

  The separated laser light passes through the objective lens 204 and is condensed at three locations on the surface of the optical disc 1. The three condensed laser beams are each reflected by the optical disc 1, pass through the objective lens 204 again, and are received by the first light receiving means 206a and the second light receiving means 206b via the hologram 213 and the collimator lens 202. The

  In order to detect a defect 101 such as dust, scratches or dirt on the optical disc 1, an arbitrary point on the surface of the optical disc 1 is a spot region based on the second laser beam 105 or a spot region based on the first laser beam 104. When passing through in order and the arbitrary point enters the spot region based on the second laser beam 105, the presence or absence of the defect 101 at the arbitrary point is detected. In the second embodiment, both the first laser beam 104 and the second laser beam 105 use the wavelength for the Blu-ray disc. However, if the light source is a light source capable of emitting a plurality of wavelengths, The laser beam 104 and the second laser beam 105 may have different wavelengths, and the first laser beam 104 and the second laser beam 105 are not limited to the wavelength for the Blu-ray disc.

  Then, when at least one of the RF signal amplitude or the reflected light level based on the reflected light of the received second laser light 105 falls below a predetermined threshold, it is determined that the defect 101 is present. As in the first embodiment, this utilizes the phenomenon that the amount of reflected light based on the second laser beam 105 always decreases when the spot region 102 based on the second laser beam 105 crosses the defect 101. is there. Here, the detection of the minimal defect 101 that hardly affects the recording or reproduction of information by the first laser beam 104 is eliminated, or a determination error caused by noise on the operation circuit is avoided. Considering this, the accuracy of the defect 101 detection can be improved.

  Next, the relationship between the spot area based on the first laser beam and the spot area based on the second laser beam and the defect position on the optical disk surface will be described.

  FIG. 9 is a diagram showing the relationship between the spot area on the optical disk surface and the defect position in the second embodiment of the present invention, and the spot area based on the first laser beam, the spot area based on the second laser beam, and the defect position. It is a figure which shows these positional relationships. In FIG. 9, 101 is a defect, 102 is a spot region based on the second laser light, 103 is a spot region based on the first laser light, and 303 is a spot region based on the third laser light.

  Two or more spots are formed on the surface of the optical disc by at least two laser beams emitted from one objective lens 204. In the second embodiment, a spot is formed by three laser beams as two or more laser beams due to the characteristics of the hologram. Then, when the optical disk 1 rotates, the hologram 213 is formed so that arbitrary points are in the order of the spot region 102 based on the second laser beam and the spot region 103 based on the first laser beam. By doing so, as shown in FIG. 9, the spot region 102 based on the second laser light, the spot region 103 based on the first laser light, and the spot based on the third laser light from the side closer to the defect 101. Spots are formed in the order of the region 303. Here, the spot region 303 based on the third laser beam is a spot formed due to the characteristics of the hologram 213 and is not actively used for the present invention.

  If the line connecting the center of the spot region 103 based on the first laser beam and the center of the spot region 102 based on the second laser beam on the surface of the optical disc 1 mounted on the optical disc apparatus is defined as line B, the line B is mounted. A hologram 213 is formed so as to be perpendicular to the radial direction of the optical disk 1 thus formed. In this way, since the defect 101 can pass through the spot region 103 based on the first laser light immediately after passing through the spot region 102 based on the second laser light, the defect 101 can be detected with high accuracy. It can be carried out. If the line B connecting the center of the spot region 103 based on the first laser beam and the center of the spot region 102 based on the second laser beam is not perpendicular to the radial direction of the mounted optical disc 1, the defect 101 Cannot pass through the spot region 103 based on the first laser beam immediately after passing through the spot region 102 based on the second laser beam, so that the flaw passage delay time T2 becomes longer and the accuracy of defect detection decreases. To do.

  In the second embodiment, with respect to the radial direction of the optical disc 1 on which the line B connecting the center of the spot region 103 based on the first laser beam and the center of the spot region 102 based on the second laser beam is mounted. However, it is not limited to these. Considering the defect detection accuracy, with respect to the radial direction of the optical disc 1 on which the line B connecting the center of the spot region 103 based on the first laser beam and the center of the spot region 102 based on the second laser beam is mounted. It is preferable to be vertical.

  Next, a defect detection method and tracking control interruption will be described.

  FIG. 10 is a diagram for explaining a defect detection method and tracking control interruption according to the second embodiment of the present invention. FIG. 10A is an addition signal obtained based on the second laser beam, and FIG. 10B is a flaw detection signal generated based on the addition signal shown in FIG. 10 (c) is an addition signal obtained based on the first laser beam, FIG. 10 (d) is a control signal for controlling the objective lens, and FIG. 10 (e) drives the objective lens. Drive signal for

  As described with reference to FIG. 9, when a defect 101 such as dust, scratches, and dirt exists at an arbitrary point on the surface of the optical disc 1, the spot region 102 based on the second laser beam first traverses the defect 101. Therefore, the influence of the defect 101 during the operation of the optical disk apparatus first appears in the addition signal obtained based on the second laser beam 105 shown in FIG. 10A, and then the first laser beam shown in FIG. It appears in the addition signal obtained based on 104.

  The defect detection signal shown in FIG. 10B is generated by the defect detection means 10 based on the addition signal obtained from the second laser beam 105 shown in FIG. As a result, it is possible to calculate the beginning of the disturbance of the control signal (tracking error signal) for controlling the objective lens 204 shown in FIG. 10 (d) that occurs T2 seconds after the rise of the scratch detection signal. Further, the time T2 ′ from the fall of the flaw detection signal necessary for the disturbance of the control signal (tracking error signal) for controlling the objective lens 204 shown in FIG. There are a case where it is calculated in advance from a spot diameter of the spot region 103 based on the above and a spot diameter of the spot region 102 based on the second laser beam 105, and a case where it is calculated from an addition signal based on the first laser beam 105. is there.

  By these methods, a control signal (tracking error signal) for controlling the objective lens 204 shown in FIG. 10D, which occurs T2 seconds after the rise of the scratch detection signal and ends after T2 ′ seconds from the fall of the scratch detection signal. Can be calculated. Here, T2 is a scratch passage delay time, that is, a difference between a time during which the second laser beam 105 passes through the defect 101 and a time during which the first laser beam 104 passes through the defect 101, and a calculation method thereof will be described later. I will do it.

  Then, the control of the objective lens 204 is interrupted until the control signal is disturbed, that is, until the defect 101 passes through the spot region 103 based on the first laser beam 104, as shown in FIG. A drive signal shown in e) is generated by the servo control means 12.

  The objective lens 204 is suspended from tracking control of the objective lens 204 until the defect 101 completes passing through the spot region 103 based on the first laser beam 104 by the generated drive signal. Since the control of the objective lens 204 is interrupted immediately before the defect 101 enters the spot region 103 based on the first laser beam 104, the probability of mistracking occurring after the tracking control is interrupted is maximized. It becomes possible to do.

  In the second embodiment, the tracking control of the objective lens 204 that emits the first laser beam 104 is interrupted immediately before the defect 101 enters the spot region 103 based on the first laser beam 104. However, the present invention is not limited to this. For example, the tracking control may be interrupted immediately after the defect 101 passes through the spot region 102 based on the second laser beam 105. Considering the probability of mistracking after the tracking control is interrupted, it is preferable to interrupt the defect 101 immediately before entering the spot region 103 based on the first laser beam 104.

  In the second embodiment, the determination of the presence or absence of the defect 101 in the detection of the defect 101 is performed when at least one of the RF signal amplitude or the reflected light level based on the reflected light of the second laser beam 105 falls below a predetermined threshold value. Although it is determined that the defect 101 is present, the present invention is not limited to this. In consideration of the accuracy of the defect 101 detection, the determination of the presence or absence of the defect 101 in the defect 101 detection is made when at least one of the RF signal amplitude or the reflected light level based on the reflected light of the second laser beam 105 falls below a predetermined threshold. It is preferable to determine that there is a defect.

  Next, the scratch passage delay time T2 will be described with reference to FIG.

  Let the linear velocity of the objective lens 204 with respect to the rotating optical disc 1 be V (m / s), and the center of the spot at the center of the spot region 103 based on the first laser beam 104 and the center of the spot region 102 based on the second laser beam 105. When the distance is L2 (m), the wound passage delay time T2 described in FIG. 10 can be calculated by L2 / V (m). In this case, a line B connecting the center of the spot region 103 based on the first laser beam 104 and the center of the spot region 102 based on the second laser beam 105 is perpendicular to the radial direction of the optical disc 1 loaded. Therefore, if it is not perpendicular to the radial direction of the mounted optical disk 1, it is necessary to consider the angle of the mounted optical disk 1 with respect to the radial direction. In addition, when the rotation speed of the spindle motor 2 that rotates the optical disk 1 is changed, it is necessary to consider the change in the rotation speed. In this way, it is possible to accurately detect the defect 101 that is harmful when recording or reproducing information using the first laser beam 104 with the second laser beam 105.

  Next, procedures for detecting the defect 101 and tracking control will be described.

  FIG. 11 is a flowchart showing defect detection and tracking control in the second embodiment of the present invention. Here, the objective lens 204 is described for a Blu-ray disc, but is not limited thereto. For example, the objective lens may be for DVD.

  When the optical disc 1 for the Blu-ray disc is mounted on the optical disc apparatus and an instruction to record or reproduce information is issued from the system for controlling the optical disc apparatus, the servo control means 12 receives the spindle motor via the motor drive means 13. 2 rotation, movement of the carriage 206, and emission of the objective lens 204.

  When the spindle motor 2 reaches a predetermined rotational speed and the carriage 206 moves to a predetermined point, the defect 101 is detected using the second laser beam 105 emitted from the objective lens 204 and separated in the middle. Information is recorded or reproduced using the first laser beam 104 emitted from the objective lens 204 and separated in the middle. At this time, the second laser beam 105 reflected from the optical disc 1 is always received by the second light receiving means 206b, and the information is sent to the defect detecting means 10 and the control signal generating means 11.

  The defect detection means 10 determines that there is a defect 101 on the surface of the optical disc 1 when at least one of the RF signal amplitude or the reflected light level based on the reflected light of the second laser beam 105 falls below a predetermined threshold value. The information is sent to the servo control means 12 (S11).

  In the servo control means 12, the spot velocity 103 and the second laser light based on the linear velocity V (m / s) of the objective lens 204 with respect to the rotating optical disc 1 and the first laser beam 104 formed on the surface of the optical disc 1. The scratch passage delay time T2 is calculated from the spot center distance L2 (m) of the spot region 102 based on 105 (S12). Thereafter, tracking control is continued during the calculated wound passage delay time T2 (S13), and parameter change and tracking control based thereon are performed after the calculated wound passage delay time T2 (S14). At this time, it is necessary to consider the time required to calculate the flaw passage delay time T2 and the time required to switch the parameter. The parameter changes performed here are tracking servo hold, servo gain change, reproduction signal synchronization PLL hold, and data slicer hold.

  Next, when at least one of the RF signal amplitude or the reflected light level based on the reflected light of the second laser beam 105 recovers to a predetermined level and exceeds a predetermined threshold, the defect detection unit 10 sends information to the servo control unit 12. The servo control means 12 determines that the defect 101 on the surface of the optical disc 1 has passed through the spot region 102 based on the second laser beam 105 (S15).

  Then, the objective lens 204 is continuously interrupted during the scratch passage delay time T2 ′ shown in FIG. 10 (S16), and the parameters changed earlier are restored after the scratch passage delay time T2 ′ has elapsed (S17). The tracking control 204 is resumed (S18). At this time, if the linear velocity V (m / s) of the objective lens 204 with respect to the rotating optical disc 1 has changed, it is necessary to calculate the wound passage delay time T2 again.

  As described above, an arbitrary point on the surface of the optical disc 1 passes through the spot region 102 based on the second laser beam 105 and the spot region 103 based on the first laser beam 104 in this order, and the arbitrary point passes through the second laser beam. When the spot region 102 based on the light 105 is entered, the presence or absence of the defect 101 at an arbitrary point is detected. Therefore, when the information is recorded or reproduced with the first laser beam 104, the harmful defect 101 is previously detected. It becomes possible to detect.

  When it is determined that the defect 101 is present by detecting the presence or absence of the defect 101, the objective that emits the first laser beam 104 until the defect 101 completes passing through the spot 103 based on the first laser beam 104. When the control of the lens 204 is interrupted, it is possible to avoid the tracking error caused by using the reflected light whose reliability of information is lowered due to the influence of the defect 101, and it is possible to avoid dust, scratches, dirt, etc. on the optical disc 1. Even if the defect 101 is relatively large, the influence of the defect 101 can be minimized, and the probability of mistracking can be reduced.

  Therefore, it is possible to make it less susceptible to the influence of the defect 101 in tracking control, and it is possible to realize an optical disc device control method and an optical disc device that can reduce the probability of mistracking.

  In the second embodiment, an arbitrary point on the surface of the optical disk 1 passes through the spot region 102 based on the second laser beam 105 and the spot region 103 based on the first laser beam 104 in order, When the point enters the spot region 102 based on the second laser beam 105, the presence or absence of the defect 101 at any point is detected, and if it is determined that the defect 101 is present, the defect 101 is the first defect 101. The case where the control of the objective lens 204 that emits the laser beam before separation is interrupted until the passage through the spot region 103 based on the laser beam 104 is completed has been described, but the presence or absence of the defect 101 at any point is detected. If it is determined that the defect 101 exists, the defect 101 Until through complete spot area 103 based on the laser light 104, also by the amount of the laser beam before separation is lowered it is possible to obtain the same effect. This is due to the fact that tracking information cannot be obtained from reflected light due to a decrease in the amount of laser light before separation.

  Since the present invention can reduce the probability of mistracking by making it less susceptible to defects in tracking control, a control method for an optical disc apparatus that performs at least one of recording and reproduction of information on an optical disc, an optical disc apparatus, and the like Can be adapted to.

1 is a block diagram of an optical pickup control system of an optical disc apparatus according to Embodiment 1 of the present invention. The figure which shows the relationship between the spot area | region on the optical disk surface in Embodiment 1 of this invention, and a defect position. The figure which shows the control signal in Embodiment 1 of this invention The figure which shows the positional relationship of the optical disk in Embodiment 1 of this invention, a 1st objective lens, and a 2nd objective lens. The figure which shows the positional relationship of the optical disk in Embodiment 1 of this invention, a 1st objective lens, and a 2nd objective lens. The flowchart which shows the defect detection and tracking control in Embodiment 1 of this invention. Block diagram of the optical pickup control system of the optical disc apparatus in Embodiment 2 of the present invention The figure which shows the optical pick-up in Embodiment 2 of this invention The figure which shows the relationship between the spot area | region on the optical disk surface in Embodiment 2 of this invention, and a defect position. The figure explaining the detection method of a defect and the interruption of tracking control in Embodiment 2 of this invention The flowchart which shows the defect detection and tracking control in Embodiment 2 of this invention. Block diagram of optical pickup control system in conventional optical disc apparatus

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical disk 2 Spindle motor 3 Pickup module 4 1st objective lens 5 2nd objective lens 6 Carriage 6a 1st light-receiving means 6b 2nd light-receiving means 7 Feed part 8 Reproduction | regeneration signal generation means 9 Reproduction | regeneration signal processing means 10 Defect detection Means 11 Control signal generation means 12 Servo control means 13 Motor drive means 101 Defect 102 Spot area based on second laser light 103 Spot area based on first laser light 203 Pickup module 204 Objective lens 206 Carriage 206a First light receiving means 206b Second light receiving means 211 Light source 212 Collimator lens 213 Hologram 303 Spot region based on third laser beam 502 Spindle motor 503 Pickup module 504 Objective lens 50 The carriage 507 feed section 508 reproduction signal generating means 509 reproduction signal processing unit 511 control signal generating unit 512 servo control unit 513 motor driving means

Claims (17)

At least a first laser beam and a second laser beam are emitted;
An arbitrary point on the optical disc surface passes through the spot area based on the second laser beam and the spot area based on the first laser beam in this order.
When the arbitrary point enters the spot region based on the second laser beam, the presence or absence of a defect at the arbitrary point is detected,
If it is determined that there is a defect,
Until the defect completes passing through the spot region based on the first laser beam,
A method of controlling an optical disc apparatus, wherein control of an objective lens that emits the first laser light is interrupted, or at least one of the light amount of the first laser light is reduced. 2. The method of controlling an optical disc apparatus according to claim 1, wherein the first laser beam and the second laser beam have different wavelengths. The control of the objective lens that emits the first laser light is interrupted immediately before the defect enters a spot region based on the first laser light. The control method of the optical disk apparatus described. 3. The optical disc apparatus according to claim 1, wherein the light amount of the first laser light is lowered immediately before the defect enters a spot region based on the first laser light. Control method. The defect detection is characterized in that it is determined that there is a defect when at least one of an RF signal amplitude or a reflected light level based on the reflected light of the second laser light falls below a predetermined threshold. 5. A method for controlling an optical disk device according to any one of 4 above. 6. The method of controlling an optical disc apparatus according to claim 1, wherein the first laser beam and the second laser beam are emitted simultaneously. The wavelength of a Blu-ray disc is used for the first laser light, and the wavelength for DVD or CD is used for the second laser light. Method for controlling the optical disk apparatus of the present invention. A rotation driving means for rotating the optical disc; a first objective lens for irradiating the optical disc with a first laser beam; a second objective lens for irradiating the optical disc with a second laser beam; Light receiving means for receiving reflected light from the optical disc, control signal generating means for generating an RF signal based on a signal received by the light receiving means, and measuring at least one of an RF signal amplitude or a reflected light level based on the reflected light A defect detecting means for detecting the presence or absence of defects on the optical disc surface, and a control unit for performing tracking control on the optical disc,
The controller is
Emitting at least a first laser beam and a second laser beam;
An arbitrary point on the optical disk surface is passed in the order of the spot area based on the second laser beam and the spot area based on the first laser beam,
When the arbitrary point enters the spot region based on the second laser beam, the presence or absence of a defect at the arbitrary point is detected,
If it is determined that there is a defect,
Until the defect completes passing through the spot region based on the first laser beam,
An optical disc apparatus characterized in that control of an objective lens that emits the first laser light is interrupted or at least one of reducing the light amount of the first laser light is performed. 9. The optical disc apparatus according to claim 8, wherein the first laser beam and the second laser beam have different wavelengths. The control of the objective lens that emits the first laser beam is interrupted immediately before the defect enters the spot region based on the first laser beam. The optical disk device described. 10. The optical disc apparatus according to claim 8, wherein the light amount of the first laser light is lowered immediately before the defect enters a spot region based on the first laser light. The line connecting the center in the radial direction of the first objective lens and the center in the radial direction of the second objective lens is perpendicular to the radial direction of the mounted optical disk. 10. The optical disk device according to any one of 9 above. When the focal length of the first objective lens is WDA and the focal length of the second objective lens is WDB,
The distance in the focus direction between the first objective lens and the second objective lens is
WDB-WDA
The optical disc device according to claim 8, wherein the optical disc device is an optical disc device. Rotation drive means for rotating the optical disk, a light source for emitting laser light to the optical disk, a hologram for separating the laser light into at least first laser light and second laser light, and reflected light from the optical disk A light receiving means for receiving light, a control signal generating means for generating an RF signal based on a signal received by the light receiving means, and measuring at least one of an RF amplitude or a reflected light level based on the reflected light of the second laser light. Defect detection means for detecting the presence or absence of defects on the optical disc surface, and a control unit for performing tracking control on the optical disc,
The controller is
An arbitrary point on the optical disk surface is passed in the order of the spot area based on the second laser beam and the spot area based on the first laser beam,
When the arbitrary point enters the spot region based on the second laser beam, the presence or absence of a defect at the arbitrary point is detected,
If it is determined that there is a defect,
Until the defect completes passing through the spot region based on the first laser beam,
An optical disk apparatus, wherein control of an objective lens that emits the laser light is interrupted. The line connecting the center of the spot region formed by the first laser beam and the center of the spot region formed by the second laser beam is perpendicular to the radial direction of the loaded optical disc. The optical disc apparatus according to claim 14. Control of an objective lens that records and reproduces information on a Blu-ray disc is controlled based on information obtained from an objective lens other than that that records and reproduces information on the Blu-ray disc. Method for controlling an optical disc apparatus. Rotation drive means for rotating the Blu-ray disc, a first objective lens for recording or reproducing information on the Blu-ray disc, and a second for recording or reproducing information on a medium other than the Blu-ray disc Objective lens, light receiving means for receiving reflected light from the Blu-ray disc, control signal generating means for generating an RF signal based on a signal received by the light receiving means, and RF signal amplitude or reflection based on the reflected light Defect detection means for measuring at least one of the light levels and detecting the presence or absence of a defect on the Blu-ray disc surface, and a control unit for performing tracking control on the Blu-ray disc,
The controller is
An optical disc apparatus, wherein the control of the first objective lens is controlled based on information obtained from the second objective lens.

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