JP2004355774A - Optical disk device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical disk device in a system of recording address information by CAPA such as DVD-RAM, capable of improving the accuracy of CAPA detection in the case of medium reading and performing stable data reproduction. <P>SOLUTION: This device is provided with an RF amplifier for generating an RF signal from an output signal of the photodetector of an optical pickup, a CAPA slicing circuit for setting a slice level to detect the CAPA part of an RFDIF signal generated from the RF signal and binarizing it, a CAPA slice level switching means for switching the slice level of the CAPA slicing circuit, and a controller capable of instructing a proper slice level to the CAPA slice level switching means according to the CAPA part reading state of the optical disk. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical disk device for reproducing information on an optical disk by an optical pickup.
[0002]
[Prior art]
As optical disk devices, audio CDs, CD-ROMs, CD-R / RWs, DVDs, and the like have already been put into practical use, and applications to various fields and developments for high performance are being actively performed. . In recent years, in particular, with the rapid expansion of the market for personal computers, the penetration rate of optical disc devices in personal computers has been increasing, and the use of portable personal computers and the use of optical discs by external connection of personal computer interfaces have been increasing. Applications are also expanding.
[0003]
Here, a configuration of a conventional optical disk device of a system for recording address information by CAPA (Complementary Allocated Pit Addressing) will be described using a DVD-RAM drive device as an example.
[0004]
FIG. 4 is a block diagram of a CAPA detection control unit of an optical disk device according to the related art, and FIG. 5 is a diagram illustrating CAPA detection in a conventional optical disk device. In FIG. 4, 1 is an optical disk, 2 is a pickup module, 3 is a spindle motor, 4 is an RF amplifier, 5 is a CAPA slice circuit, 6 is a DSP, 7 is a CAPA slice level switching means, 8 is a controller, and 9 is an optical pickup. is there.
[0005]
In FIG. 4, the pickup module 2 includes a spindle motor 3 for rotating the optical disc 1 and an optical pickup 9. The optical pickup 9 irradiates the optical disk 1 with a light spot of laser light, and the reflected light is detected by an optical sensor (not shown) provided inside the optical pickup 9. The RF amplifier 4 extracts an RF signal based on a signal output from the optical sensor, and outputs an RFDIF signal generated from the RF signal to the CAPA slice circuit 5. The CAPA slice circuit 5 has a function of switching a threshold (slice level) for detecting a CAPA portion of the RFDIF signal input from the RF amplifier 4. The setting of the slice level is output from the controller 8, and a predetermined fixed value is input to the CAPA slice circuit 5 via the CAPA slice level switching means 7.
[0006]
Next, the mechanism of CAPA detection will be described with reference to FIG. In FIG. 5, a waveform A represents an RFDIF signal. Waveform B represents a recognized waveform when CAPA detection is performed. 11 is a CAPA signal, 14 is a portion recognized as CAPA, 12 is a portion where the output of the wobble signal suddenly increases, 10 is a CAPA slice level for binarizing the CAPA, and 13 is a reference voltage for slicing. is there. The CAPA portion is detected by setting a CAPA slice level 10 in advance, and when a light spot passes through the CAPA region portion of the optical disk, only the portion of the CAPA signal included in the RFDIF signal exceeds the CAPA slice level 10. Is
[0007]
In this way, the drive reads the address data of the disk by separating the CAPA portion from the data portion.
[0008]
Prior examples include (Patent Document 1) and (Patent Document 2).
[0009]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 2003-036542 [Patent Document 2]
Japanese Patent Application Laid-Open No. 2003-016680
[Problems to be solved by the invention]
In DVD-RAM disks, wobbles recording media address information are recorded along the grooves of the disk at the time of manufacture of the disk, and appear in RFDIF signals. However, some DVD-RAM disks are mass-produced. In some cases, the amplitude of the wobble signal is partially increased due to variation in the wobble signal. In addition, the amplitude of the wobble signal may be partially detected to be larger than the actual amplitude due to vibration or the like during reproduction by the optical disk device. When the wobble amplitude partially increases, the portion may exceed the CAPA slice level. If this phenomenon occurs during data reading, an erroneous address is read, and at the worst, the exact position on the disk cannot be determined, and the disk data cannot be read, so the optical disk device ends with an error.
[0011]
SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an optical disc apparatus such as a DVD-RAM, which records address information in CAPA, improves the accuracy of CAPA detection when reading media, and provides stable data. It is an object of the present invention to provide an optical disk device capable of reproducing.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, an optical disc apparatus according to the present invention comprises: an optical pickup that condenses a light spot on the optical disc using an objective lens to record and reproduce data; and an optical pickup of the optical pickup. An RF amplifier that generates an RF signal from an output signal of a detector, a CAPA slice circuit that detects a CAPA portion of an RFDIF signal generated from the RF signal by setting a slice level, and further performs binarization; A CAPA slice level switching means for switching a slice level of a circuit, and a controller capable of instructing the CAPA slice level switching means of an appropriate slice level in accordance with a reading state of a CAPA section of the optical disk.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
According to a first aspect of the present invention, there is provided an optical pickup for recording / reproducing data by condensing a light spot on the optical disk by using an objective lens on the optical disk, and a photodetector of the optical pickup. An RF amplifier that generates an RF signal from an output signal, a CAPA slice circuit that detects a CAPA portion of an RFDIF signal generated from the RF signal by setting a slice level, and performs binarization, and a slice of the CAPA slice circuit An optical disc apparatus comprising: a CAPA slice level switching means for switching a level; and a controller capable of instructing the CAPA slice level switching means on an appropriate slice level in accordance with a reading state of a CAPA section of the optical disc. , The optimal CAPA selected by the controller By setting the rice level, the optical disk apparatus even if disturbance occurs in the wobble signal when the leading DVD-RAM media, can be realized an optical disk apparatus capable of performing stable data reproduction.
[0014]
The invention according to claim 2 of the present invention is characterized in that the instruction of the slice level includes a procedure of repeating the detection operation while changing the value of the slice level when the CAPA portion cannot be detected. The optical disk device described above can realize an optical disk device capable of performing stable data reproduction even when a wobble signal is disturbed when the optical disk device reads a DVD-RAM medium.
[0015]
The invention according to claim 3 of the present invention includes a step of repeating the detection operation while changing the value of the slice level from a low value to a high value. Even when a wobble signal is disturbed when reading a DVD-RAM medium, the function of performing stable data reproduction can be further improved.
[0016]
The invention according to claim 4 of the present invention includes a step of changing the value of the slice level from a low value to a high value once or a plurality of times and then returning to a first slice level value. The optical disk device described above can further improve the function of performing stable data reproduction even when a wobble signal is disturbed when the optical disk device reads a DVD-RAM medium.
[0017]
According to a fifth aspect of the present invention, in the optical disk device according to the third aspect, the initial value of the slice level is set at about 50% of the average level of the peak value of the CAPA signal. Becomes more appropriate, and more stable data reproduction can be performed.
[0018]
The invention according to claim 6 of the present invention is characterized in that the slice level value is set in two stages of a low value and a high value, and the high value is set near 150% of the low value. According to the optical disk device, the slice level setting becomes more appropriate, and more stable data reproduction can be performed.
[0019]
The invention according to claim 7 of the present invention is characterized in that a peak value of a CAPA signal is detected upon power-on, and a slice level is set within a range of 25% to 75% of a potential of the peak value. According to the optical disk device described in the item 2, even if the amplitude level of the CAPA signal is slightly different due to the difference between the disk and the optical disk device, the optimum slice level can be set, and more stable data reproduction can be performed.
[0020]
The invention according to claim 8 of the present invention is characterized in that a peak value of a CAPA signal is detected upon power-on, a first slice level is set to around 50% of the potential of the peak value, and a CAPA portion is set at the first slice level. 3. An optical disk device according to claim 2, wherein the next slice level in the case where the signal cannot be detected is set to around 75% of the potential of the peak value. Even if the levels are slightly different, the optimum slice level can be set, and more stable data reproduction can be performed.
[0021]
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0022]
(Embodiment)
FIG. 1 is a block diagram of a CAPA detection control unit of an optical disc device according to one embodiment of the present invention. In FIG. 1, 1 is an optical disk, 2 is a pickup module, 3 is a spindle motor, 4 is an RF amplifier, 5 is a CAPA slice circuit, 6 is a DSP, 7 is a CAPA slice level switching circuit, and 8 is a controller.
[0023]
In FIG. 1, the pickup module 2 includes a spindle motor 3 for rotating the optical disc 1 and an optical pickup 9. The RF amplifier 4 generates an RF signal based on a signal output from an optical sensor (not shown) formed inside the pickup module 2, and generates an RFDIF signal from the RF signal. Here, the RF signal is a data signal of the optical disc 1 extracted by the pickup module 2, and the RFDIF signal is a signal generated from a sum signal of the RF signals.
[0024]
The RF amplifier 4 outputs an RFDIF signal to the CAPA slice circuit 5. The CAPA slice circuit 5 detects the CAPA portion of the RFDIF signal and binarizes the CAPA portion. Unlike the normal data portion, the CAPA portion is recorded at a position shifted from the groove portion of the disk, so that a potential is generated in the RFDIF signal. The detection of the CAPA portion of the RFDIF signal is performed by setting the CAPA slice level 10 so that only the portion of the CAPA signal exceeds the level.
[0025]
The slice level is set in the CAPA slice circuit 5 through a CAPA slice level switching means 7 in accordance with a command from a CPU whose predetermined level is 8.
[0026]
The sliced and binarized CAPA signal is output to the DSP 6 and recognized as the DVD-RAM address information.
[0027]
Next, the operation of the CAPA detection control according to the embodiment of the present invention will be described in detail with reference to FIGS. FIG. 2 is a diagram for explaining the CAPA detection of the optical disk device according to one embodiment of the present invention, and FIG. 3 is a flowchart showing the operation of the CAPA detection control unit according to one embodiment of the present invention. In FIG. 2A, the waveform A is an RFDIF signal, and the waveform B is a recognized waveform when CAPA detection is performed, and shows a state where there is a large portion in the wobble signal amplitude and the portion exceeds the slice level of the CAPA detection. I have. In FIG. 2B, a waveform C is an RFDIF signal, and a waveform D is a recognized waveform when CAPA detection is performed. There is a large portion in the wobble signal amplitude. This shows a state in which the level is prevented from being exceeded. 10 is a CAPA slice level, 10a is a CAPA slice level A, 10b is a CAPA slice level B, 11 is a CAPA signal, 12 is a portion of the RFDIF signal where the wobble signal amplitude is locally increased, and 13 is a reference voltage for slicing. , 14 are portions recognized as the CAPA portion of the CAPA recognition waveform.
[0028]
When the power is turned on, the controller 8 sets the slice level. First, a command is issued to the CAPA slice level switching circuit 7 to set the first-stage CAPA slice level A10a set by the controller 8 in the CAPA slice circuit 5 (S1). The address read (S2) is started while the state of the set CAPA slice level A10a is maintained.
[0029]
Next, it is determined whether the address information recorded on the optical disc has been read (S3). Here, the fact that the address read was successful means that only the CAPA signal 11 exceeds the CAPA slice level 10 in the RFDIF signal as shown by the waveform A in FIG. Is read by the controller 8. At this time, the CAPA detection signal obtained when the RFDIF signal exceeds the CAPA slice level 10 becomes a normal signal as shown in a waveform B. If the address read is successful, the next address read is performed while maintaining the CAPA slice level 10 (S4). It is determined whether the target address specified by the host computer has been reached (S5). If not reached, the address read is continued at the CAPA slice level 10 as much as possible. When it reaches the target address, it returns a read end to the host computer and waits for an instruction from the host computer.
[0030]
In addition, when the address cannot be read at the point of S3, that is, as shown in FIG. 2B, the locally large portion 12 of the wobble amplitude exceeds the CAPA slice level A10a, but is not the CAPA. If the controller 8 cannot read the address data that should be written in the controller 8, the first-stage CAPA slice level A10a set by the controller 8 is changed to the CAPA slice level B10b, and reading is resumed (S7). To change the slice level, the controller 8 outputs the CAPA slice level B10b to the CAPA slice circuit 5, and switches the CAPA slice level switching circuit 7. The CAPA slice level B10b is set to a higher potential than the CAPA slice level A10a. It is determined whether the address read was successful (S8). If the address read was successful, that is, the CAPA slice level is changed from the CAPA slice level A10a to the CAPA slice level B10b as shown in FIG. If only the portion 11 exceeds the CAPA slice level B10b, the next address read is performed while maintaining the CAPA slice level B10b (S9). It is determined whether the target address specified by the host computer has been reached (S10). If not reached, the address read is continued at the CAPA slice level B10b as much as possible. When it reaches the target address, it returns a read end to the host computer and waits for an instruction from the host computer.
[0031]
If the address cannot be read at the point in S8, it is determined whether the number of times that the address was not read is an arbitrary predetermined number n (S12). If the number of loops is equal to or less than an arbitrary predetermined number n, the CAPA slice level 1 is returned to the CAPA slice level A10a to perform address reading (S11), and the process returns to the point of S3. This is because the abnormality of the wobble signal output is limited and may be eliminated by performing the address read again. If the number of times that the address read could not be performed exceeds the predetermined number of times n, the process is terminated with NG, or the read NG is returned to the host computer.
[0032]
The level of the CAPA slice level A10a is set to be close to 50% of the average level of the peak value E of the CAPA signal, which varies slightly depending on the disc or optical disk device, and the level of the CAPA slice level B10b is the level of the CAPA slice level A10a. When it is set to around 150%, good detection stability can be obtained.
[0033]
In the present embodiment, the slice level is two levels set in advance. However, when the slice level is a plurality of levels equal to or more than three levels and address reading cannot be performed, the level can be sequentially increased from the low potential level in the same manner as described above. It is.
[0034]
Further, as a method of setting the CAPA slice level, the peak value E of the CAPA signal is detected when the power is turned on, and the CAPA slice level is set within a range of 25% to 75% of the potential of the peak value E. The optimum CAPA slice level can be set even if the amplitude level of the RFDIF signal is slightly different due to the difference in the optical disk device. More specifically, when the power is turned on, the peak value E of the CAPA signal is detected, the CAPA slice level A10a is set to 50% of the peak value E of the CAPA signal, and the CAPA slice level B10b is 75% of the peak value E of the CAPA signal. By setting to%, an optimal slice level can be set.
[0035]
As described above, by setting the optimum CAPA slice level selected by the controller in accordance with the read state of the CAPA section of the DVD-RAM by switching the CAPA slice level, the optical disk apparatus reads the DVD-RAM medium. Even if the wobble signal is disturbed, stable data reproduction can be performed.
[0036]
【The invention's effect】
An optical pickup that condenses a light spot on the optical disc using an objective lens on the optical disc to record and reproduce data, an RF amplifier that generates an RF signal from an output signal of a photodetector of the optical pickup, A CAPA slice circuit that sets a slice level to detect a CAPA portion of an RFDIF signal generated from the RF signal and performs binarization; a CAPA slice level changing unit that switches a slice level of the CAPA slice circuit; By providing a controller capable of instructing the slice level switching means to an appropriate slice level in accordance with the read state of the CAPA section of the optical disk, the wobble signal is disturbed when reading DVD-RAM media. Can detect CAPA stably, In which an optical disk device capable were the data reproduction can be realized.
[Brief description of the drawings]
FIG. 1 is a block diagram of a CAPA detection control unit of an optical disk device according to one embodiment of the present invention; FIG. 2 is a diagram illustrating CAPA detection of an optical disk device according to one embodiment of the present invention; FIG. 4 is a flowchart showing the operation of a CAPA detection control unit according to one embodiment; FIG. 4 is a block diagram of a CAPA detection control unit of an optical disk device according to a conventional technique; FIG. 5 is a diagram illustrating CAPA detection in a conventional optical disk device; Description】
DESCRIPTION OF SYMBOLS 1 Optical disk 2 Pickup module 3 Spindle motor 4 RF amplifier 5 CAPA slice circuit 6 DSP
7 CAPA slice level switching means 8 Controller 9 Optical pickup 10 CAPA slice level 10a CAPA slice level A
10b CAPA slice level B
11 Capa signal 12 RFDIF signal locally increased wobble signal output 13 Reference voltage 14 Capa recognized part of CAPA recognized waveform

Claims (8)

An optical pickup that condenses a light spot on the optical disc using an objective lens on the optical disc to record and reproduce data, an RF amplifier that generates an RF signal from an output signal of a photodetector of the optical pickup, A CAPA slice circuit that sets a slice level to detect a CAPA portion of an RFDIF signal generated from the RF signal and performs binarization; a CAPA slice level switching unit that switches a slice level of the CAPA slice circuit; An optical disc apparatus comprising a controller capable of instructing a slice level switching means on an appropriate slice level in accordance with a read state of a CAPA section of the optical disc. 2. The optical disk device according to claim 1, wherein the instruction of the slice level includes a procedure of repeating the detection operation while changing the value of the slice level when the CAPA portion cannot be detected. 3. The optical disk apparatus according to claim 2, further comprising a procedure of repeating the detection operation while changing the slice level value from a low value to a high value. 3. The optical disk apparatus according to claim 2, further comprising a procedure of changing the slice level value from a low value to a high value once or a plurality of times and returning to a first slice level value. 4. The optical disk device according to claim 3, wherein the initial value of the slice level is set to be around 50% of the average level of the peak value of the CAPA signal. 4. The optical disk device according to claim 3, wherein the slice level value is set in two stages of a low value and a high value, and the high value is set near 150% of the low value. 3. The optical disk apparatus according to claim 2, wherein a peak value of the CAPA signal is detected when the power is turned on, and a slice level is set within a range of 25% to 75% of the potential of the peak value. When the power is turned on, the peak value of the CAPA signal is detected, the first slice level is set near 50% of the potential of the peak value, and the next slice level when the CAPA portion cannot be detected at the first slice level is set. 3. The optical disk device according to claim 2, wherein the potential is set at about 75% of the potential of the peak value.

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