JP2004355773A - Optical disk device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical disk device capable of reading from an optical disk in which data are written by local detracking. <P>SOLUTION: This device is provided with an objective lens driving means for moving an objective lens in a tracking direction, a tracking servo control means for driving the objective lens driving means based on a signal reproduced from an optical disk to perform a tracking operation, and an error determining means for determining whether there are any reading errors or not in data read from the optical disk. When the presence of a reading error is determined in the data read from the optical disk by the error determining means, the tracking servo control means shifts the locus of an optical spot in a diameter direction by the objective lens driving means to read again from the reading error place. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical disk device that can read data from an optical disk.
[0002]
[Prior art]
FIG. 5 is a block diagram showing the configuration of a conventional optical disk device, and FIG. 6 is a flow chart of the logical judgment of the CPU when a reading error occurs in the conventional optical disk device.
[0003]
5, a read-only memory (ROM) 18 has a program storage area for storing a control program according to the flowchart shown in FIG. 6, and a recording control program for the optical disk device. Reference numeral 19 denotes a main memory, which is used as a storage area necessary for various recording control and reproduction control in addition to a storage area necessary for control. Reference numeral 2 denotes a feed motor, which is driven by a feed motor driver 6. A spindle motor 3 is driven by a spindle motor driver 7. Reference numeral 4 denotes a pickup unit, which is driven by an actuator driver 8. The servo processor 15 controls the feed motor driver 6, the spindle motor driver 7, and the actuator driver 8 by servo control. The pickup unit 4 has a built-in laser diode, and an LD driver 5 that drives the laser diode is controlled by an encoder 10 and a read amplifier 9. The ROM encoder 11 obtains data to be recorded from the buffer memory 12 which stores the data, performs an encoding process for recording, and inputs the result to the encoder 10.
[0004]
In the reproducing system, optical signals obtained from the optical disk 1 and the pickup unit 4 are signal-processed by the read amplifier 9 and used as a feedback signal to the servo processor 15, as well as an input signal of the ATIP detector 13, and an output signal of the encoder 10. Feedback to The decoder 14 is for demodulating the CD signal, performs data demodulation using the output signal of the servo processor 15, and stores the result in the buffer memory 12. The buffer memory 12 is a memory for temporarily storing recording data and demodulated data. These data are exchanged with the host computer via the ATAPI interface unit 21 by communication using the IDE bus 22. The system bus 16 is a bus for data transfer in the optical disk device. The temperature signal 23 is a signal obtained from a temperature sensor in the pickup unit, is digitized through an A / D converter 24, and is processed by the CPU 17 as a digital value.
[0005]
Next, processing when a reading error occurs will be described with reference to FIG.
[0006]
When a reading error (read error) occurs (S1), the disk address of the location where the error occurred is stored (S2), and the location where the error occurred is read (read retry) again based on the disk address (S3). ). If the reading is performed again, the process proceeds to the main process. If a reading error occurs, the number of read retries is checked (S4). It is determined whether the number of read retries has not reached a predetermined number (S5). If the number of read retries does not exceed the predetermined number, the process returns to S3. If the number of read retries exceeds a predetermined number, the number of rotations of the disk is reduced to reduce the occurrence of read errors (S6). It is determined whether the number of rotations of the disk is lower than a predetermined number of rotations (S7). If the rotational speed of the disk has not dropped below the predetermined rotational speed, the process returns to S3. If the number of rotations of the disc is lower than the predetermined number of rotations, the process proceeds to read error processing. The read error process includes a process of returning a read error status to the host computer. In many cases, the host computer determines that reading cannot be performed and stops the reading operation of the optical disk device. Prior examples include (Patent Document 1) and (Patent Document 2).
[0007]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 2003-045056 [Patent Document 2]
JP 08-129766 A
[Problems to be solved by the invention]
In a writing optical disc such as a CD-R / RW, a DVD-R / RW, or a DVD-RAM, at the time of writing, the written bit is locally detracked, i.e., in the radial direction, due to the servo characteristics of the drive, vibration, or impact. May be written slightly off. It is very rare and rarely possible to write with detracking from the beginning, but it is usually impossible, but the detracking state temporarily occurs due to vibration / shock during writing or abnormal feed control, and writing continues as it is Often it is. In many cases, the reciprocal of the time from occurrence of such detrack to return to the original state, that is, the frequency component, is higher than the normal tracking servo control band. For this reason, if a writing system optical disk written including such a detrack is read by a drive that wrote the data or by another drive, the servo cannot be followed at a location where the detrack was written, so The laser beam spot deviates from the position where the pits exist, and a phenomenon occurs in which data demodulation from the disk is not performed normally. As a result, the reading speed is reduced by repeating the read retry, and in the worst case, the reading may be stopped.
[0009]
[Means for Solving the Problems]
In order to solve this problem, the present invention relates to an optical pickup device for reproducing and / or recording data by focusing a light spot on an optical disk using an objective lens on the optical disk. And a tracking servo control unit for performing a tracking operation by driving the objective lens driving unit based on a signal reproduced from the optical disc, and a reading error occurs in data read from the optical disc. Error tracking means for determining whether or not there is an error, and when the error determination means determines that there is a reading error in the data read from the optical disk, the tracking servo control means controls the light by the objective lens driving means. Shift the spot trajectory in the radial direction to read It was decided to time lead.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
The invention according to claim 1 is an optical pickup device for reproducing and / or recording data by condensing a light spot on an optical disk using an objective lens on the optical disk, wherein the objective lens is moved in a tracking direction. An objective lens driving unit that drives the objective lens driving unit based on a signal reproduced from the optical disk, and a tracking servo control unit that performs a tracking operation. An error determining unit for determining whether or not the data read from the optical disc has a read error by the error determining unit. Shift the orbit in the radial direction and read the error location again The optical disk apparatus according to claim Rukoto can perform reading of data correctly even for locally optical disc detrack state was then data is written occurred.
[0011]
According to a second aspect of the present invention, the disk address position when a reading error occurs and the offset condition given to the tracking servo system at the time of reading are stored in the temporary storage means in association with each other, and the disk address position is separately stored at the time of reading separately. 2. An optical disk device according to claim 1, wherein when the disk drive reaches a position near the disk address position stored in the means, an offset condition corresponding to the stored disk address position is given to the tracking servo system. Data can be accurately read from an optical disk on which data has been written due to the occurrence of a detrack state, and a delay in the reading time in the second and subsequent reading can be prevented.
[0012]
According to a third aspect of the present invention, the operation of shifting the tracking trajectory in the radial direction includes an operation of shifting radially inward and an operation of shifting radially outward, and a reading error occurs in one of the two operations. 2. The optical disk device according to claim 1, wherein when the error occurs, the other operation is performed, and when a reading error occurs in both operations, an operation of returning the tracking to a state before the shift is performed. Data can be read accurately even in the detrack state.
[0013]
According to a fourth aspect of the present invention, when it is determined that there is a reading error in the data read from the optical disk, the data can be read while the rotation speed of the optical disk is gradually reduced to a predetermined lower rotation speed than normal. The optical disk device according to claim 1, which includes a procedure for repeating reading until data can be read even in a detrack state where reading is more difficult.
[0014]
The invention according to claim 5 is characterized in that the offset amount is one or several fixed values determined in advance, and the data is written by the local occurrence of a detrack state by the optical disk device according to claim 1. Data can be read from the read optical disk by an easy method.
[0015]
According to a sixth aspect of the present invention, the offset amount is a change amount, and the optical disk apparatus according to the first aspect can read data even in a detrack state where reading is more difficult.
[0016]
The invention according to claim 7 is characterized in that the disk address position at the time of occurrence of a reading error and the offset condition given to the tracking servo system at the time of reading are stored in temporary storage means until the optical disk is taken out of the optical disk device. With the optical disc device described in item 2, it is possible to prevent a delay in the reading time in the second and subsequent reading.
[0017]
In the invention according to claim 8, the temporary storage means stores the disk address position at the time of the occurrence of the read error and the disk identification information read from the disk in association with the offset condition given to the tracking servo system at the time of the read, in association with each other. At least a part of the contents stored in the storage means is retained until a separately determined period, and when the disk identification information of the separately mounted optical disk matches the disk identification information stored in the storage means, the disk address position is read. 2. The optical disk device according to claim 1, wherein when the data reaches a position near the disk address position stored in the temporary storage means, an offset condition corresponding to the stored disk address position is given to the tracking servo system. When using multiple optical discs, It is possible to prevent the delay of the reading time by.
[0018]
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0019]
FIG. 1 is a block diagram showing a configuration of an optical disk device according to an embodiment of the present invention. FIG. 2 is a flowchart of a logical judgment by a CPU when a reading error occurs in the optical disk device according to an embodiment of the present invention. FIG. 4 is a diagram for explaining the operation of the optical disk device according to one embodiment of the present invention, and FIG. 4 is a diagram showing an example of a temporary storage unit in a main memory of a reading error occurrence position of the optical disk device according to one embodiment of the present invention.
[0020]
In FIG. 1, reference numeral 18 denotes a read-only memory (ROM), which has a program storage area for storing a control program according to the flowchart shown in FIG. 2 and a recording control program for an optical disk device. Reference numeral 19 denotes a main memory, which is used as a storage area necessary for various recording control and reproduction control in addition to a storage area necessary for control. Reference numeral 2 denotes a feed motor, which is driven by a feed motor driver 6. A spindle motor 3 is driven by a spindle motor driver 7. Reference numeral 4 denotes a pickup unit, which is driven by an actuator driver 8. The servo processor 15 controls the feed motor driver 6, the spindle motor driver 7, and the actuator driver 8 by servo control. The pickup unit 4 has a built-in laser diode, and an LD driver 5 that drives the laser diode is controlled by an encoder 10 and a read amplifier 9. The ROM encoder 11 obtains data to be recorded from the buffer memory 12 which stores the data, performs an encoding process for recording, and inputs the result to the encoder 10.
[0021]
In the reproducing system, optical signals obtained from the optical disk 1 and the pickup unit 4 are signal-processed by the read amplifier 9 and used as a feedback signal to the servo processor 15, as well as an input signal of the ATIP detector 13, and an output signal of the encoder 10. Feedback to The decoder 14 is for demodulating the CD signal, performs data demodulation using the output signal of the servo processor 15, and stores the result in the buffer memory 12. The buffer memory 12 is a memory for temporarily storing recording data and demodulated data. These data are exchanged with the host computer via the ATAPI interface unit 21 by communication using the IDE bus 22. The system bus 16 is a bus for data transfer in the optical disk device. The temperature signal 23 is a signal obtained from a temperature sensor in the pickup unit, is digitized through an A / D converter 24, and is processed by the CPU 17 as a digital value.
[0022]
Next, a re-read operation when a read error occurs, which is a characteristic part of the present invention, will be described in detail with reference to FIGS.
[0023]
When a reading error (read error) occurs (S1), the address position of the disk where the error occurred is stored (S2), and based on the address position, the disk is returned to the position before the error occurred (S3). An offset (1) is added to the tracking (S4). The offset {circle around (1)} shifts a predetermined amount toward the inner side or the outer side with respect to the normal tracking. Then, the portion where the reading error has occurred is read again (S5), and it is determined whether or not reading is possible (S6). If reading is possible, the tracking setting and the address of the disk at the time of reading are stored in the main memory 19 (S15), and the process returns to the main processing. If the data cannot be read, the process returns to the position where the error occurred based on the stored address of the disk where the error occurred (S7), and adds an offset (2) to the tracking (S8). The offset {circle around (2)} shifts a predetermined amount toward the inner circumference or the outer circumference with respect to the normal tracking, but shifts in the opposite direction to the offset {1}. Then, the portion where the reading error has occurred is read again (S9), and it is determined whether or not reading is possible (S10). If reading is possible, the tracking setting and the address of the disk at the time of reading are stored in the main memory 19 (S15), and the process returns to the main processing. If the data cannot be read, the disk is returned to the position before the error based on the stored address of the disk where the error occurred (S11), and the tracking offset is returned to the original position, that is, in S1 without the offset. (S12). Then, the portion where the reading error has occurred is read again (S13), and it is determined whether or not reading is possible (S14). If reading is possible, the tracking setting and the address of the disk at the time of reading are stored in the main memory 19 (S15), and the process returns to the main processing. If the data cannot be read, the process proceeds to read error processing. The read error process includes a process of returning a read error status to the host computer. For example, the host computer determines that reading is not possible and stops the reading operation of the optical disk device.
[0024]
Next, the actual movement of the laser spot according to the flowchart of FIG. 2 will be described in detail with reference to FIG. FIG. 3A is an enlarged view of one track on the recording surface of the disk, and shows a case where pits are normally formed on the on-track. FIG. 3B shows one track on the recording surface of the disk. FIG. 3 (c) is an enlarged view showing a case where pits are formed by detracking partially on the inner peripheral side of the disk, and FIG. 3 (c) is an enlarged view of one track on the recording surface of the disk. This shows a case where pits are formed by detracking on the outer peripheral side of the disk.
[0025]
Reference numeral 27 denotes pits, which are data written on the writing disk surface and formed by a writing operation of a writing drive such as a CD-R / RW, a DVD-R / RW, and a DVD-RAM. Reference numeral 26 denotes a track area (on-track area) where the pit 27 is formed. If the pit 27 is normally formed on the on-track, the pit 27 is formed in this area. In addition, the pit 27 can be servo-followed for the shift in the radial direction in this area. Reference numeral 25 denotes a region where the pit 27 is not formed and a gap between the region where the adjacent pit 27 is formed. Reference numeral 28 denotes a laser spot for reading.
[0026]
When the pit 27 is normally formed on the on-track by the writing operation of the writing drive, the pit 27 is formed in the on-track area 26 as shown in FIG. The spot 28 can scan on the pit 27.
[0027]
On the other hand, a detrack state occurs temporarily due to vibration / shock or an abnormal feed control during the writing operation of the writing system drive. However, when writing is continued as it is, the pits 27 as shown in FIG. , A detrack section 29 partially deviating from the on-track area 26 occurs. Here, the pit 27a is detracked on the inner circumference side of the disk. In this case, the spot position 28a of the first laser having no offset deviates from the pit 27a, and a reading error occurs (FIG. 2 (S1)). When a read error occurs, the address position of the disk at this location is stored (FIG. 2 (S2)), and based on this address position, the process returns to the position where the read error occurred (FIG. 2 (S3)). Next, the offset (1) is added to the tracking (FIG. 2 (S4)), and the portion where the read error has occurred is read again (FIG. 2 (S5)). If the direction of offset (1) is the offset amount A on the inner circumferential side of the disk, the laser spot position is 28b and the on-track area is 26a. Since the partially detracked pit 27a becomes on-track and becomes readable, the tracking setting at the time of reading, that is, the offset direction, the offset amount A, and the address position are stored (FIG. 2 (S15)), and the process returns to the main processing. .
[0028]
Also, as shown in the detrack section 30 in FIG. 3C, when the pits are detracked toward the outer circumference of the disk, the offset (1) is an offset toward the inner circumference of the disk, and therefore, the offset (1) is maintained even after the offset. Cannot read. Therefore, the position returns to the position where the read error has occurred (FIG. 2 (S7)), the offset (2) is added to the tracking (FIG. 2 (S8)), and the position where the read error has occurred is read again (FIG. 2). (S9)). The offset direction of the offset (2) is opposite to the offset direction of the offset (1), and in this case, is on the outer peripheral side of the disk. Assuming the offset amount B, the laser spot position becomes 28c and the on-track area becomes 26b. Since the partially detracked pit 27b becomes on-track and becomes readable, the tracking setting at the time of reading, that is, the offset direction, the offset amount B and the address position are stored (FIG. 2 (S15)), and the process returns to the main processing. .
[0029]
As described above, the detrack section 29 or the detrack section 30 partially deviating from the on-track area 26 can be read by the processes of FIG. 2 (S1) to (S10). When the pit 27 returns to the state shown in FIG. 3A again, the track is detracked with the offset added. Therefore, in FIGS. 2 (S6) and (S10), the determination is NO, and it is possible to return to the state without offset in the process from (S11) to (S14).
[0030]
If the detrack amount is large and the offset amounts A and B do not become on-track, the determinations of (S6), (S10) and (S14) are all NO, and the process proceeds to the read error process.
[0031]
Incidentally, the offset (1) may be an offset in the disk outer peripheral direction, and the offset (2) may be an offset in the disk inner peripheral direction. When the offset amounts A and B are fixed values determined from the assumed detrack amount of the pit, the tracking setting stored in S15 may be only the offset direction. Further, the offset amounts A and B may be variable amounts that change with the track scanning, for example, may be variable amounts that gradually increase and decrease with the track scanning. Further, the offset amount is preferably a fixed value or a change amount between 20% and 50% of the track width, and more preferably a fixed value or a change amount between 25% and 35% of the track width.
[0032]
In addition, a routine for reading and retrying while lowering the rotation of the disk to a predetermined value as shown in S5 to S7 in FIG. 6 of the related art is added. If reading cannot be performed by S14, the rotation of the disk is determined in advance. The routine of FIG. 2 may be repeated while dropping to the specified value.
[0033]
FIG. 4 shows an example of a means for temporarily storing the reading error occurrence location in the main memory 19. The tracking setting and the storage of the address position at the time of reading, which are performed in FIG. 2 (S15), are performed by attaching an index number to the memory and using the disk address of the reading error location and the offset amount given to the tracking servo system.
[0034]
Since the information on the offset temporarily stored in the main memory 19 is retained until the disk is ejected, the disk address position corresponding to the read command from the host computer is stored in the main memory 19 in the subsequent reading until the disk is ejected. In the same case, the tracking offset amount and the direction corresponding to the disk address position are given to the tracking servo system so that a reading error does not occur and the time until the data is read can be shortened. Further, the memory for storing the information regarding the offset may be a memory external to the optical disk device such as a host computer. Also, if the information storage period is longer than before the disk is ejected and the disk identification information is also stored, it is possible to avoid reading errors and shorten the reading time in the above process for multiple past disks that have been read once. It can be performed. For example, there is a method in which the information storage period is set based on the number of loaded disks, the information is stored until the number reaches the preset number, and when the number exceeds the set number, the information on the old disk is deleted.
[0035]
【The invention's effect】
The present invention relates to an optical pickup device for reproducing and / or recording data by condensing a light spot on an optical disk using an objective lens with respect to the optical disk, and driving the objective lens in a tracking direction. Means, and a tracking servo control means for performing a tracking operation by driving the objective lens driving means based on a signal reproduced from the optical disc, and determining whether there is a reading error in data read from the optical disc. When the error determination means determines that there is a reading error in the data read from the optical disc, the tracking servo control means causes the objective lens driving means to change the trajectory of the light spot in the radial direction. And read the error location again. As a result, data can be read even from an optical disk on which data has been written due to the occurrence of a locally detracked state. Becomes possible.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a configuration of an optical disk device according to an embodiment of the present invention. FIG. 2 is a flowchart of a logical determination of a CPU when a reading error occurs in the optical disk device according to an embodiment of the present invention. FIG. 4 is a diagram for explaining the operation of the optical disk device according to one embodiment of the present invention. FIG. 4 is a diagram showing an example of a temporary storage unit in a main memory of a reading error occurrence position of the optical disk device according to one embodiment of the present invention. 5 is a block diagram showing a configuration of a conventional optical disk device. FIG. 6 is a flowchart of a logical judgment of a CPU when a reading error occurs in a conventional optical disk device.
Reference Signs List 1 optical disk 2 feed motor 3 spindle motor 4 pickup unit 5 LD driver 6 feed motor driver 7 spindle motor driver 8 actuator driver 9 read amplifier 10 encoder 11 ROM encoder 12 buffer memory 13 ATIP detector 14 decoder 15 servo processor 16 system bus 17 CPU
18 ROM
Reference Signs List 19 main memory 20 nonvolatile memory 21 ATAPI interface unit 22 IDE bus 23 temperature signal 24 A / D converter 25 area where no pit is formed 26 on-track area 26a on-track area 26b on-track area 27 pit 27a pit 27b pit 28 laser spot 28a Laser spot position 28b Laser spot position 28c Laser spot position 29 Detrack section 30 Detrack section

Claims (8)

An optical pickup device for reproducing and / or recording data by condensing a light spot on an optical disk using an objective lens with respect to the optical disk, comprising: objective lens driving means for moving the objective lens in a tracking direction; Error determining means for determining whether or not there is a read error in data read from the optical disc, comprising tracking servo control means for performing a tracking operation by driving the objective lens driving means based on a signal reproduced from the optical disk. When the error determination means determines that there is a read error in the data read from the optical disk, the tracking servo control means shifts the trajectory of the light spot in the radial direction by the objective lens drive means. Light for re-reading a reading error portion Disk apparatus. The disk address position at the time of occurrence of the reading error and the offset condition given to the tracking servo system at the time of reading are stored in the temporary storage means in association with each other, and the disk address position at the time of reading separately is stored in the temporary storage means. 2. The optical disk apparatus according to claim 1, wherein when the distance has reached the vicinity, an offset condition corresponding to the stored disk address position is given to the tracking servo system. The operation of shifting the tracking trajectory in the radial direction includes an operation of shifting inward in the radial direction and an operation of shifting outward in the radial direction.If a reading error occurs in one of the two operations, the other operation is performed. 2. The optical disk device according to claim 1, wherein when a reading error occurs in both operations, an operation of returning tracking to a state before the shift is performed. If it is determined that there is a reading error in the data read from the optical disk, the method should include a step of repeating reading until the disk becomes readable while gradually reducing the rotation speed of the optical disk to a rotation speed lower than a predetermined normal rotation speed. The optical disk device according to claim 1, wherein: 2. The optical disk device according to claim 1, wherein the offset amount is one or several fixed values determined in advance. 2. The optical disk device according to claim 1, wherein the offset amount is a change amount. 3. The optical disk device according to claim 2, wherein the disk address position at the time of occurrence of the read error and the offset condition given to the tracking servo system at the time of reading are stored in a temporary storage unit until the optical disk is removed from the optical disk device. The temporary storage unit stores the disk address position at the time of the reading error and the disk identification information read from the disk in addition to the offset condition given to the tracking servo system at the time of reading in association with each other, and stores the contents stored in the storage unit. At least a part is retained until a separately determined period, and when the disk identification information of the separately mounted optical disk matches the disk identification information stored in the storage unit, the disk address position is stored in the temporary storage unit by reading. 2. The optical disk apparatus according to claim 1, wherein when the disk drive reaches the vicinity of the disk address position, an offset condition corresponding to the stored disk address position is given to the tracking servo system.

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