JP2004046987A - Optical disk drive - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the reproduction quality and restore the erased data of an optical disk drive erases which the data on an optical disk by over-writing. <P>SOLUTION: Data to be erased is read from an optical disk, data to be over-written based on the data is decided, over-writing is performed so that edges of a mark and a space of data after erase (over-writing) are not deviated from the edges of a mark of data before erasing, further, making information about data making for over-writing is preserved, and it is used for restoration of data. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical disk device for erasing data on an optical disk to which data can be written only once.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, an optical disk apparatus that erases data of an optical disk that can be written only once (hereinafter, referred to as write-once) is described in JP-A-2001-209944.
[0003]
FIG. 9 is a block diagram showing the configuration of this conventional optical disk device.
In FIG. 9, reference numeral 10 denotes an optical disk such as a CD-R or DVD-R, which can be recorded only once, 15 a spindle motor, 20 an optical head having a laser diode, an objective lens, and a photodetector, and 30 a high-frequency signal of reproduced data. Circuit, a PLL circuit for extracting a clock from reproduction data, 45, a synchronization detection circuit for detecting a synchronization pattern, 50, a CPU, 55, a counter, 60, EFM demodulation from a reproduction signal when data is read. , CIRC (Cross-Interleave Reed-Solomon code) decoding and a decoder / encoder that performs decoding processing such as error correction processing, which is the reverse of reading processing at the time of recording, and 70 is an ATIP (Absolute Time) in Pregroove) and synchronization detection Cormorant is a ATIP decoder.
[0004]
This conventional optical disc apparatus aims to avoid the possibility that the rest of the data on the optical disc 10 cannot be reproduced by erasing the absolute address when erasing the partial data. In this case, only the data on the optical disk 10 to be erased is double-written to erase the data. Specifically, after the reproduction data read from the optical head 20 is amplified by the amplification circuit 30, the clock is extracted by the PLL 40, the synchronization detection circuit 45 detects the frame synchronization pattern indicating the start position of the frame, and the counter 55 In, the laser spot output from the optical head 20 detects a synchronization pattern for a target frame. Thereafter, the time until the laser spot reaches the data and the parity part in the frame to be erased and the time until the data and the parity part in the frame to be erased end are measured. While the laser spot output from the optical head 20 is on the data and parity in the frame, the laser power of the optical head 20 is set to be higher than the power at the time of writing, for example, a fixed pattern such as 6T or random data. Is overwritten on the data to be erased.
[0005]
[Problems to be solved by the invention]
However, when performing the data erasing process, regardless of the already recorded data, the fixed or random data is recorded by applying the laser power for recording. It is formed at a random position regardless of the pit position before double writing. Therefore, by this erasing process, a mark or space having a length other than 3T to 11T, which does not originally exist, is formed.
[0006]
However, this problem poses a problem in a Viterbi decoder which has been introduced to increase the reading rate with the increase in the density of DVDs and the digitization of circuits. In designing a Viterbi decoder, an effective mark and space length are limited for the purpose of simplifying the circuit.
[0007]
Therefore, when an erased frame is played back, if a non-standard pattern, for example, data having a length of 14T or 20T, is input during playback of the erased frame, the processing of the Viterbi decoder is disturbed, There is a problem that an error rate becomes high in a decoding process of a frame next to a frame subjected to erasure. In particular, when a long mark is formed by double writing, it takes a long time to eliminate the influence of the long mark in the Viterbi decoder. For this reason, there arises a problem that the ability to reproduce the unerased data and the address information of the frame to be erased is reduced.
[0008]
SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide an optical disc apparatus capable of efficiently and reliably reproducing data from an optical disc on which data has been erased by double writing. I do.
[0009]
[Means for Solving the Problems]
In order to solve this problem, the present invention (claim 1) is an optical disk apparatus for recording or reproducing information by irradiating a light spot from an optical pickup onto an optical disk, wherein the information is erased from the optical disk. Erasing data generating means for generating data for double writing based on power data, and control means for controlling to double-write the data generated by the erasing data generating means on data to be erased on the optical disk. It is provided with.
As a result, double writing based on the data before erasing can be performed, and data can be erased without deteriorating the reproduction quality when reading data from the disk from which data has been erased. .
[0010]
Further, according to the present invention (claim 2), in the optical disc device according to claim 1, the erasure data generating means is configured to determine a length of a mark length and an adjacent space of data after double writing on the disc. The double writing data is generated such that the maximum value and the minimum value are not different from the maximum value and the minimum value of the length of the adjacent space and the mark length of the data before the double writing.
This makes it possible to suppress the deterioration of the read performance even when reading the disk after erasing by a normal optical disk device.
[0011]
According to a third aspect of the present invention, there is provided the optical disk device according to the second aspect, further comprising a data storage unit that reads out and stores data to be erased from the optical disk before erasing the data.
This eliminates the need to separately prepare data for performing double writing.
[0012]
According to a fourth aspect of the present invention, in the optical disk device according to the third aspect, the data storage unit stores the data reproduced from the optical disk and binarized as it is.
This eliminates the need for a special device for reading, and can suppress an increase in the circuit scale for reading from the disk in order to perform double writing.
[0013]
According to a fifth aspect of the present invention, in the optical disk device according to the third aspect, the data storage means stores data reproduced from the optical disk, binarized, decoded, and error-corrected. is there.
Thereby, the quality of the read data for double writing can be improved.
[0014]
Further, the present invention (claim 6) is an optical disc apparatus for recording or reproducing information by irradiating a light spot from an optical pickup onto an optical disc, wherein the optical disc apparatus has Creation information storage means for recording creation information of double-write data, reading data from the optical disk after the data has been erased, and restoring the read data based on the information stored in the creation information storage means Data restoring means.
As a result, the data once erased can be restored.
[0015]
Further, according to the present invention (claim 7), in the optical disk device according to claim 6, the data storage means for reading out and storing the data to be erased from the optical disk before erasing the data, and the data storage means And an erasing data generating means for generating the data for double writing based on the data stored in the erasing data, and writing the data generated by the erasing data generating means on the data to be erased on the optical disk. And control means for controlling.
This eliminates the need to separately prepare data for performing double writing.
[0016]
Further, according to the present invention (claim 8), in the optical disc device according to claim 7, the erasure data generating means is configured to determine, according to a length of an adjacent space and a mark, which is data on the optical disc before erasure. The double writing data is created.
As a result, the size of data required for data restoration can be suppressed.
[0017]
According to a ninth aspect of the present invention, in the optical disk device according to the eighth aspect, the erasure data generating means determines the length of the adjacent space and the mark, each space being nT (n is an integer, and T is The data for double writing is created so as to be shorter by (channel clock cycle) and longer by nT.
As a result, the size of data required for data restoration can be further reduced.
[0018]
According to a tenth aspect of the present invention, in the optical disk device according to the ninth aspect, the data restoring means reads the data from the optical disk after the data is erased, and reads the lengths of all adjacent spaces and marks. Are corrected so that the space is longer by nT and the mark is shorter by nT, respectively, to restore the data.
As a result, the size of data required for data restoration can be further reduced.
[0019]
Further, according to the present invention (claim 11), in the optical disc device according to claim 6, the creation information storage means stores the creation information in a free area of the optical disc.
This facilitates management of the creation information and the erasure data.
[0020]
Also, the present invention (claim 12) relates to an optical disc device for recording or reproducing information by irradiating a light spot from an optical pickup onto an optical disc, wherein an object to be erased from the optical disc prior to erasure of data. A data storage means for reading and storing data, and a fixed value mT (where m is an integer, E is an erasure data generating means for generating data for double writing so that a space is short and a mark is long by T (a channel clock cycle), and data generated by the erasure data generation means is to be erased on the optical disk. Control means for controlling the data to be double-written, and reading the data from the optical disk after the data has been erased Data restoration means for correcting the length of the adjacent space and the length of the mark uniformly by a fixed value mT (m is an integer, T is the channel clock cycle) so that the mark is shortened and the data is restored. Things.
Thus, data can be restored without having information on the data for erasure.
[0021]
Further, the present invention (claim 13) is an optical disc apparatus for recording or reproducing information by irradiating a light spot from an optical pickup onto an optical disc, wherein data to be erased is erased when data is erased. Transferring data from the host computer, erasing data generating means for generating double-writing data based on the data transmitted by the data transferring means, and data generated by the erasing data generating means on the optical disk. And control means for controlling to double-write the data to be erased.
Thus, the management of the erasing data can be performed by the host computer, and the control becomes easy.
[0022]
According to a fourteenth aspect of the present invention, in the optical disk device according to the thirteenth aspect, prior to data restoration, data transfer means for transferring data necessary for restoration from the host computer, and the data transfer means Data restoration means for restoring data read from the optical disk based on the transmitted data.
This makes it possible to easily manage data necessary for data restoration.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
(Embodiment 1)
In the first embodiment, desired information (data) is written in data recorded on a write-once optical disc by double-writing only the data in the frame and the parity portion so as not to erase address information and the like. ), The position of each edge of the double-written data mark (or space) recorded on the disc should not be shifted from the edge of the data mark to be erased, The present invention relates to an optical disk device that generates double-written data based on a space length and a mark length of data to be erased and performs erasure such that each length of a mark and a space becomes 3T to 11T.
[0024]
Hereinafter, an optical disc device according to the first embodiment of the present invention will be described with reference to FIGS. 1, 2, and 3. FIG.
FIG. 1 is a block diagram illustrating a configuration of an optical disc device according to Embodiment 1 of the present invention.
In FIG. 1, reference numeral 10 denotes an optical disk, which is described as a once-writable CD-R, but may be another medium such as a DVD-R. Reference numerals 15 to 70 are the same as those of the conventional technology, 100 is a memory for storing data, 110 is an erase data generation circuit for generating data for double writing at the time of erasure, 120 is a selector, and 130 is a read clock and a write clock. A PLL 140, which is generated by switching between clocks, is a binarizing circuit 140 for binarizing reproduced data composed of a Viterbi decoder, and 145 is an EFM demodulation, a CIRC decoding, and an error decoding from a reproduced signal at the time of reading normal data. The encoder / decoder performs not only decoding processing such as correction processing but also processing for generating recording data.
[0025]
Next, the operation of the optical disk device according to the first embodiment having the above configuration will be described.
In the optical disk device according to the first embodiment, the erasure of data already recorded on the optical disk 10 is performed in such a procedure. That is, prior to erasing, data to be erased is once read into the memory 100, data to be double-written is created based on the read data, and data to be erased on the optical disk 10 is double-written.
[0026]
Next, a process of reading data to be erased will be described first.
The optical disk 10 is rotated by the spindle motor 15, and a laser beam is emitted from the optical head 20. Based on the reflected light from the optical disk 10, reproduced data of a high-frequency signal is output from the optical head 20 and supplied to the amplifier circuit 30 for amplification. After that, it is supplied to the PLL circuit 130.
After the reproduction data input to the binarization circuit 140 is binarized, the synchronization detection circuit 45 detects a frame synchronization pattern. Further, the binarized reproduction data is input to the encoder / decoder 145 together with the clock signal, and when the counter 55 confirms that the reproduction data is data in a frame and reproduction data of a parity part, the input reproduction data is stored in a memory. Stored in 100.
[0027]
The confirmation of the data and the parity part in the frame here is performed by the following processing. A clock signal is extracted from the reproduced data signal in the PLL circuit 130, and a counter 55 measures the time elapsed from the detection of the frame pattern by the synchronization detection circuit 45, and the synchronization detection circuit 45 newly detects the frame pattern. Upon detection, the counter 55 is cleared, and re-measurement of the elapsed time is started.
[0028]
By this processing, the time until the laser spot reaches the data and the parity part in the frame is measured, and the data in the frame and the data in the frame after the laser spot reaches the head of the parity part and the data in the frame as the target position are measured. The CPU 50 controls the decoder / encoder 145 based on the interrupt signal output from the counter 55 so that the binary data output from the synchronization detection circuit 45 is stored in the memory 100 as it is until the end of the parity section. In this manner, the data of the frame corresponding to the file to be erased can be read from the optical disk, and the mark and space length of the reproduced data can be stored in the memory 100 without being demodulated by the encoder / decoder 145.
[0029]
Next, the double writing process performed on the recorded data will be described.
When the double writing process is started, the decoder / encoder 145 reads out the stored data from the memory 100 prior to the double writing process and reads the data to be double-written by the erase data generation circuit 110 based on this data. After that, the output of the erase data generation circuit 110 is selected by the selector 120.
In parallel with this processing, the optical head 20 is moved to a position on the optical disk immediately before the read frame, and reading is performed until the laser spot comes to the pit position of the frame to be erased.
[0030]
Confirmation of the pit position is performed as follows. The synchronization detection circuit 45 detects the frame synchronization pattern, and the counter 55 counts the clock signal from the detection of the frame synchronization pattern until the start of the target pit to detect the target pit position. By this processing, the time until the laser spot reaches the data and parity part in the frame is measured, and when the laser spot reaches the target position, an interrupt signal is output to the CPU 50, and the CPU 50 executes the double-write processing. Control to start. Further, when the laser spot reaches the end of the parity section, an interrupt signal is output to the CPU 50 again, and the CPU 50 controls to end the double writing process.
When the double writing process is started according to an instruction from the CPU 50, the output of the selector 120 is supplied to the pickup 20 through the amplifier circuit 30, and data to be erased is recorded on the optical disk 10.
[0031]
Here, the data to be double-written is created in the erase data generation circuit 110 as follows.
Data to be double-written is determined by focusing on the length of each of the continuous space and the mark. At this time, it is necessary to make the length of the mark and the space on the optical disk 10 after the double writing fall within the range of 3T to 11T. In order to observe this rule, the erasure data generation circuit 110 determines the length of the mark to be double-written in the space portion as described below, and generates erasure data.
[0032]
For example, when the input data sequence is a combination of (n) Mark- (x) Space- (m) Mark,
If n + x + m <11,
Mark after double writing (n + x + m)
A mark having a length x is recorded in the space portion so as to eliminate the space portion.
Here, n, x, and m indicate the lengths of the corresponding spaces or marks, respectively, and after the mark of length nT (T represents the clock cycle of the input data), the length is added. This indicates that the combination is a space of xT followed by a mark of length mT. This is the same in the following description.
[0033]
Further, the erasing data is determined as follows.
When the input data is a combination of (n) Space- (x) Mark,
When n = 11
(N) The Space part is
(3) Space- (5) Mark- (3) Space
The 5T mark is double-written in the middle of the 11T space so that
[0034]
When x <10 and 3 <n <11
(Ny) Space- (x + y) Mark
The mark of yT is double-written immediately before the mark so that
Here, y is a value that is randomly determined so that both (ny) and (x + y) become 3 or more and 11 or less, or a fixed value.
[0035]
When n = 3
(3) space- (x) Mark
Do not write the mark twice so that
[0036]
Thus, by determining the position and length of the mark to be double-written, the space length and the mark length can be kept within the range of 3T to 11T even after double-writing.
Also, when double writing (recording) is started, reproduced data cannot be obtained. Therefore, in order to accurately perform the double writing so that the pit position does not shift, the PLL 130 adjusts the phase of the recording clock and the reproduction clock until reaching the target pit position where double writing is started. The clock is switched when the target pit position is reached.
[0037]
FIG. 2 is a block diagram illustrating a configuration of the PLL 130.
2, 150 and 175 are phase comparators, 155 and 180 are low-pass filters (hereinafter, referred to as LPFs), 160 is a selector, 165 and 185 are voltage controlled oscillators (hereinafter, referred to as VCOs), and 170 is a crystal. It is a transmitter. The phase comparator 150, the LPF 155, and the VCO 165 constitute a reading PLL, and the phase comparator 175, the LPF 180, and the VCO 185 constitute a recording PLL. The selector 160 selects a clock to be output.
[0038]
At the time of reading, the selector 160 selects and outputs the output of the VCO 165 so as to constitute a PLL for reading. The reproduced data is input to the phase comparator 150 together with the clock signal output from the VCO 165, a phase comparison between the two signals is performed, the phase difference is filtered by the LPF 150, and then input to the VCO 165, where The transmission frequency of the output clock signal is controlled accordingly. At this time, in order to double-write data at an accurate pit position, the phase comparator 175 compares the phase of the clock signal output from the VCO 165 via the selector 160 with the clock signal output from the crystal oscillator 170. Even if a clock signal output from the VCO 185 is selected by the selector 160, it can be immediately followed.
[0039]
When the recording is performed after reaching the target pit position, that is, while the counter 55 is outputting the data parity signal, the selector 160 selects and outputs the output of the VCO 185. Even if this switching is performed, since the phase comparison is performed at the time of reading as described above, the clock signal output from the VCO 185 is switched to the recording clock without any significant disturbance.
[0040]
In the case of performing double writing, the laser power in the optical head 20 is controlled by a laser control circuit (not shown) so that the laser power in the optical head 20 is increased to the recording power level when recording a mark, as in normal recording. . Further, the minimum space / mark length during normal recording is 3T, but a short mark of 1T or 2T must be recorded during double writing at the time of erasing. In the first embodiment, double writing may be performed so as to lengthen the mark after the space, that is, to lengthen the front side of the mark. Therefore, as long as the first edge of the double writing can be accurately recorded, even in the case of recording a 1T or 2T mark, recording can be performed using the same write strategy as in 3T, or using only the peak power during recording. Either way, you can record accurately.
[0041]
FIG. 3 is a schematic diagram of pits (marks) on the medium before erasing and after erasing (double writing). In this example, the mark length before erasure is 3T, 5T, and 6T, and the space length is 9T and 4T. After erasing, a mark of 1T length is double-written before the 5T mark and the 6T mark, the mark length becomes 6T and 7T, respectively, and the space length before each mark is 9T to 8T. , From 4T to 3T. Due to the change of the data, the data cannot be correctly reproduced even if the data is reproduced. Further, by erasing all data of the file to be erased, it becomes difficult to reproduce data by error correction.
[0042]
As described above, in the optical disc device according to the first embodiment, the clock is made to follow the change from the read to the write, the PLL is generated by switching between the read clock and the write clock, and the binarization is performed to binarize the reproduction data. A circuit, a memory for recording the data to be erased read from the optical disk 10, and an erase data generator for generating data for double writing based on the data to be erased so that the length of the space or mark is within 3T to 11T. Since the circuit 110 is provided, the mark length and space length of the erased data can be limited within the range of 3T to 11T without changing the position of the pit on the optical disk when erasing the data. After erasing the data, the data can be efficiently and accurately reproduced from the optical disk.
[0043]
In the description of the first embodiment, an example has been described in which data is processed in units of frames, and data read without performing EFM demodulation and error correction is stored in the memory 100. However, processing is performed in units of 96 frames. It is also possible to implement a configuration in which the data is stored in the memory 100 after the error correction such as CIRC is performed after the EFM demodulation.
[0044]
(Embodiment 2)
In the second embodiment, information of double-written data is stored as KEY information on the configuration of the above-described first embodiment, and data read later from the disk and data erased by the KEY information are stored. The present invention relates to an optical disk device capable of restoring an optical disk.
[0045]
Hereinafter, the optical disc device according to the second embodiment of the present invention will be described with reference to FIGS.
FIG. 4 is a block diagram showing a configuration of an optical disk device according to Embodiment 2 of the present invention.
[0046]
In FIG. 4, reference numeral 320 denotes double-written data information, which is a KEY storage device (creation information storage) for storing creation information (hereinafter, referred to as KEY information) used when restoring erased data. Device), 310 is an erasure data generation circuit that generates data for double writing, and 300 is a decoding process such as EFM demodulation, CIRC decoding, and error correction from a reproduction signal at the time of reading normal data. In addition to performing the process, when reading the erased (double-written) data, the process of decoding the data from the reproduction data based on the KEY information stored in the KEY storage device 320 and the process of generating the recording data at the time of erasing The encoder / decoder 300 also functions as a data restoration circuit. The other components are the same as those in the first embodiment.
[0047]
Next, the operation of the optical disk device according to the second embodiment having the above configuration will be described.
In the optical disk device according to the second embodiment, the erasure of the already recorded data on the optical disk 10 and the restoration of the once erased data are performed when the data and the parity part in the frame are erased only. Is stored as KEY information, and the data is restored based on the data read from the disk later and the KEY information.
[0048]
First, the operation at the time of erasing will be described.
The operation at the time of erasing is almost the same as that of the first embodiment. When erasing data, data to be erased is once read into the memory 100 in frame units. To read data, the optical disk 10 is rotated by the spindle motor 15, a laser beam is emitted from the optical head 20, and a high-frequency signal of reproduced data is output from the optical head 20 based on the reflected light from the optical disk 10, After being supplied and amplified, it is supplied to the PLL circuit 130. In the PLL circuit 130, a clock signal is extracted from the reproduced data signal, and this clock signal is input to the counter 55 to count the number of clocks.
[0049]
The reproduction data is input to a binarization circuit 140, and is binarized by a binarization circuit for binarizing the reproduction data composed of a Viterbi decoder. The counter 55 measures the time that has elapsed since the synchronization detection circuit 45 detected the frame pattern.
Further, the binarized reproduced data is input to the encoder / decoder 300 together with the clock signal, and when it is confirmed by the counter 55 that the reproduced data is data in a frame and reproduced data of a parity part, the input reproduced data is stored in a memory. Stored in 100.
[0050]
Next, in order to erase the data, double writing is performed based on the data in the memory 100. The erase data generation circuit 310 generates data for double writing as follows.
When the input data is a combination of (n) Space- (x) Mark,
When x = 11
(N) Space- (11) Mark
Do not double-write the mark so that
[0051]
When n = 3
(3) space- (x) Mark
Do not double-write the mark so that
[0052]
3 <n and x <11
(Ny) Space- (x + y) Mark
The mark of yT is double-written immediately before the mark so that
Here, y is a value that is randomly determined so that both (ny) and (x + y) become 3 or more and 11 or less, or a fixed value.
[0053]
In this way, by determining the position and length of the mark to be double-written, it is possible to fit the space length and mark length from 3T to 11T even after double-writing. In the above description, the value of y may be a fixed value or a variable value that changes randomly.
However, at the time of data generation, the erase data generation circuit 300 outputs the length of the space shortened by duplicating the mark, that is, the newly recorded mark length, as KEY information.
[0054]
That is, 0 when x = 11 or n = 3,
When 3 <n and x <11, y is used as KEY information.
Output to the key storage device 320, and the key storage device 320 sequentially stores the key information.
[0055]
When the erasing of the frame is completed or when data cannot be stored in the KEY storage device 320 again, the KEY information in the KEY storage device 320 is recorded in an empty area on the disk 10. If the erasure of all the frames of the file to be erased has been completed, the erasure processing is ended. If the erasure has not been completed, the erasure of the frames is restarted. When the KEY information is stored, if there is no free space on the optical disk 10 or, instead of storing it on the optical disk 10, the KEY information may be sent to a host computer (not shown), and the KEY information may be held by the host computer.
[0056]
Next, an operation for restoring the deleted file will be described.
When restoring a file once erased, first, the KEY information of the file to be restored is read from the disk 10 or, if stored in the host computer, from the host computer and stored in the KEY storage device 320.
[0057]
Thereafter, data is read from a frame on the optical disk 10 corresponding to the KEY information stored on the KEY storage device 320. Since the read data cannot be decoded by the encoder / decoder 300 as it is, the KEY information is sequentially read from the KEY storage device 320, and a combination of (n) Space- (x) Mark of the input data and the KEY storage device 320 The read key information is made to correspond to the read order, and the space / mark length of the reproduced data is corrected, and the data is decoded. That is, correction is made to be (n + y) Space- (xy) Mark by the combination of (n) Space- (x) Mark of the input data and the KEY information y read from the KEY storage device 320. EFM demodulation, CIRC decoding, and error correction are performed on the data on which the correction has been performed, and the data is reproduced.
[0058]
FIG. 5 is a schematic diagram of pits (marks) and KEY information on a medium before erasing and after erasing (double writing).
In FIG. 5, the mark lengths before erasing were 3T, 5T and 6T, but after erasing are 3T, 7T and 7T, and the KEY information created at the time of recording is 0T, 2T, And 1T.
[0059]
A combination of the KEY information 0T, 2T, and 1T and (n) Space- (x) Mark, that is, (3) Space- (3) Mark, (5) Space- (7) Mark, and (3) With Space- (7) Mark, (3) Space- (3) Mark, (7) Space- (5) Mark, and (4) Space- (6) Mark can be restored.
[0060]
At the time of restoration, a space and a subsequent mark are managed as one set, and correction is performed based on the corresponding KEY information so that the space length is longer by the KEY information and the mark length is shorter by the KEY information. By performing this correction, data before erasing can be restored.
[0061]
As described above, in the optical disk device according to the second embodiment, when erasing (double-writing) data on the disk, KEY information for creating double-writing data based on the data to be erased is stored in the memory. With this configuration, the erased data can be read from the disk as needed, and the original data can be restored using the KEY information corresponding to the data.
[0062]
In the description of the second embodiment, an example has been described in which data read out without performing EFM demodulation or error correction is stored in the memory 100 without processing in units of frames. However, processing is performed in units of 96 frames. A configuration in which data is stored in the memory 100 after error correction such as CIRC after EFM demodulation is also possible.
[0063]
(Embodiment 3)
According to the third embodiment, the data in the frame on the disk and the parity portion are double-written so that the address information and the like are not erased. Using a binarization circuit composed of a Viterbi decoder corresponding to the pit length of the pit, the double writing is performed so that the relationship between the data before the double writing and the overwritten data is uniquely determined when erasing the data. The present invention relates to an optical disk device capable of performing restoration by using only data read from a disk.
[0064]
Hereinafter, an optical disc device according to the third embodiment of the present invention will be described with reference to FIGS.
FIG. 6 is a block diagram showing a configuration of an optical disc device according to Embodiment 3 of the present invention.
[0065]
In FIG. 6, steps 10 to 140 are the same as those in the first and second embodiments described above, and reference numeral 400 binarizes reproduction data including a Viterbi decoder corresponding to a pit length of 2T to 12T. A binarization circuit 410 is an encoder / decoder that decodes data from reproduced data and generates recording data, and 420 is an erase data generation circuit.
[0066]
Next, the operation of the optical disc device according to the third embodiment having the above configuration will be described.
First, the operation at the time of erasing will be described. The operation at the time of erasing is performed in substantially the same manner as in the first and second embodiments.
The optical disk 10 is rotated by the spindle motor 15, and a laser beam is emitted from the optical head 20. Based on the reflected light from the optical disk 10, reproduced data of a high-frequency signal is output from the optical head 20 and supplied to the amplifier circuit 30 for amplification. After that, it is supplied to the PLL circuit 130. In the PLL circuit 130, a clock signal is extracted from the reproduced data signal, and the clock signal is input to the counter 55 to count the number of clocks.
[0067]
After being input to the binarization circuit 400 and binarized by the Viterbi decoder, it is input to the synchronization detection circuit 45 to detect a frame synchronization pattern, and the counter 55 detects the frame pattern after the synchronization detection circuit 45 detects the frame pattern. Measure the elapsed time.
Further, the binarized reproduced data is input to the encoder / decoder 410 together with the clock signal, and when it is confirmed by the counter 55 that the data is the data in the frame and the reproduced data of the parity part, the input reproduced data is stored in the memory. Stored in 100.
[0068]
The erasing (double writing) process performed on recorded data will be described below. First, the optical head 20 is moved to a position on the optical disk immediately before the read frame, and reading is performed until the laser spot comes to the pit position of the frame to be erased.
[0069]
The detection of the pit position is performed as follows. The synchronization detection circuit 45 detects the frame synchronization pattern, and the counter 55 counts the clock signal from the detection of the frame synchronization pattern until the start of the target pit, thereby detecting the target pit position.
[0070]
When the pit position to be erased is reached, data is read from the memory 100, and based on this data, the erase data generation circuit 420 creates data to be double-written and supplies it to the pickup 20 through the amplifier circuit 30 for erasing. Is recorded on the optical disc 10. In the case of performing double writing, similarly to the case of normal recording, when recording a mark, a laser control circuit (not shown) controls the laser power in the optical head 20 to be increased to the recording power level. Is done.
[0071]
The data to be double-written is created in the erase data generation circuit 420 as follows. Data to be double-written is determined by focusing on the length of each of the continuous space and the mark. At this time, the length of the mark and the space on the optical disk 10 after the double writing is made to fall within the range of 2T to 12T.
[0072]
The erasure data generation circuit 420 determines the length of a mark to be overwritten on a space portion as described below, and generates erasure data.
When the input data is a combination of (n) Space- (x) Mark,
(N-1) Space- (x + 1) Mark
1T mark is double-written immediately before the mark so that In this way, by determining the position and length of the mark to be double-written, each space length and mark length can be kept within the range of 2T to 12T even after double-writing. Here, the mark is always double-written so as to be 1T longer, so that the relationship between the data before erasure and the data after erasure is unique.
[0073]
Next, data restoration processing will be described below.
At the time of data restoration, the reproduced data read from the optical disk 10 is amplified by the amplifier circuit 30 and then binarized in the binarization circuit 400 by the Viterbi decoder corresponding to the pit length from 2T to 12T. , The encoder / decoder 410 corrects the reproduction data space so as to be 1T longer and the mark shorter by 1T, that is, after correcting (n + 1) Space− (x−1) Mark, and then performing normal EFM demodulation and CIRC. Data can be restored by performing decoding and decoding processing such as error correction processing. Although the relationship between the data before erasure and the data after erasure is unique, the range of the recorded mark and space length is different from that before erasure, so that it cannot be read by other optical disk devices, and the data security Sex is preserved.
[0074]
FIG. 7 is a schematic diagram of pits (marks) on a medium before erasing and after erasing (double writing). In FIG. 7, the mark lengths before erasing were 3T, 5T and 6T, but after erasing, the mark lengths were 4T, 6T and 7T, and the space lengths immediately before the marks were 2T, 6T and 3T. Become. Further, at the time of reproduction, an operation reverse to this operation is performed, and data before erasure can be reproduced without using key information.
[0075]
Thus, in the optical disc device according to the third embodiment, the Viterbi decoder of the binarization circuit 400 corresponds to the mark length of 2T to 12T, and the erase data generation circuit 420 determines that the mark length of the original data is Since double-written data is created so as to be 1T longer and data to be erased on the optical disk 10 is double-written, the data before erasure and the data after erasure have a unique relationship, Data restoration can be performed without having KEY information on the data. Further, since the mark and space lengths of the data before erasure and the data after erasure are different, the disk after erasure cannot be reproduced by another optical disk device, and the confidentiality of the data is maintained. Further, the configuration of the memory, the key storage device, and the like can be omitted, and an optical disk device that can be deleted and restored at low cost can be provided.
[0076]
(Embodiment 4)
According to the fourth embodiment, data for performing double writing at the time of erasing and KEY information are stored and managed in a file device of the host computer. The present invention relates to an optical disk device capable of erasing and restoring data without having a memory for storing read data by reading and transferring the data to an encoder / decoder.
[0077]
Hereinafter, an optical disc device according to Embodiment 4 of the present invention will be described with reference to FIG.
FIG. 8 is a block diagram showing a configuration of an optical disk device according to Embodiment 4 of the present invention.
In FIG. 8, reference numeral 530 denotes a file device for storing data for erasing data and KEY information as information for restoring data, 520 denotes a host computer (hereinafter referred to as HOST), and 510 denotes a host computer 520. HOSTI / F 500 is an encoder / decoder that decodes data from reproduction data based on the KEY information stored in the file device 530 and generates recording data, and 540 is an erasure data generation device. . Other components are the same as those in the second embodiment.
[0078]
Next, the operation of the optical disk device according to the fourth embodiment having the above configuration will be described.
First, the operation at the time of erasing will be described. The operation at the time of erasing is performed in substantially the same manner as in the first and second embodiments.
When erasing data, the optical disk 10 is rotated by the spindle motor 15, a laser beam is irradiated from the optical head 20, and based on the reflected light from the optical disk 10, reproduced data of a high-frequency signal is output from the optical head 20 and amplified. After being supplied to the circuit 30 and amplified, it is supplied to the PLL circuit 130. In the PLL circuit 130, a clock signal is extracted from the reproduced data signal, and this clock signal is input to the counter 55 to count the number of clocks.
[0079]
The reproduced data is input to a binarization circuit 140, binarized by a Viterbi decoder, and then input to a synchronization detection circuit 45, where a frame synchronization pattern is detected. The time elapsed since detection is measured.
[0080]
Further, the binarized reproduced data is input to the encoder / decoder 500 together with the clock signal, and is subjected to decoding processing such as EFM demodulation, CIRC decoding, and error correction processing from the reproduced signal. Forward. The HOST 520 stores the data in the file device 530 as an erasure file.
Based on the data stored in the file device 530, the data on the optical disk 10 is double-written, and the double writing for erasing the data is performed.
[0081]
The erasing (double writing) process performed on recorded data will be described below.
When the double writing process is started, first, the HOST 500 reads data from the file device 530 to erase the data, and transfers the data to the encoder / decoder 500 via the HOST I / F 510. The encoder / decoder 500 performs the same encoding processing as in normal recording based on the transferred data, and outputs the same to the erase data generation circuit 540. In the erase data generation circuit 540, data for performing double writing is created by the same processing as in the second embodiment, and the output of the erase data generation circuit 540 is selected by the selector 120, and amplified by the selector 540. Output to the circuit 30.
[0082]
In parallel with this processing, the optical head 20 is moved to a position on the optical disk immediately before the read frame, and reading is performed until the laser spot comes to the pit position of the frame to be erased. When the optical head 20 is moved and the laser spot reaches the position of the pit to be erased, the CPU 50 controls the amplifying circuit 30 to start the double writing process so that the recording process is performed.
[0083]
The erase data generation circuit 540 transfers the KEY information created at the time of creating data for performing double writing to the HOST 520 via the HOST I / F 510, and stores the KEY information in the file device 530. The KEY file is transferred to the HOST 520 at the timing when the double writing in the frame unit, the packet unit in 96 frames, or the file unit is completed.
[0084]
Next, an operation for restoring the deleted file will be described.
When restoring a file once erased, the HOST 520 first reads the key information of the file to be restored from the file device 530 and transfers the KEY information to the encoder / decoder 500 via the HOST I / F 510. The transfer of the KEY information is performed in frame units, 96 frame units, or file units.
[0085]
Then, data is read from the frame on the optical disk 10 corresponding to the KEY information. Since the read data cannot be decoded by the encoder / decoder 500 as it is, the KEY information is associated with the combination of (n) Space- (x) Mark of the input data in the reading order, and the space / mark of the reproduced data is obtained. The length is corrected and the data is decoded. The data subjected to this correction is subjected to EFM demodulation, CIRC decoding and error correction to reproduce the data.
[0086]
As described above, in the optical disk device according to the fourth embodiment, the HOST 520 stores data for performing double writing at the time of erasing and KEY information in the file device 530 and restores the data when the HOST 520 restores the data. By reading data from the file device 530 and transferring it to the encoder / decoder 500, data can be erased and restored without having a memory for storing read data.
[0087]
【The invention's effect】
As described above, according to the present invention, based on the data to be erased, the data to be double-written is determined so that the maximum and minimum values of the space after erasing and the mark length are the same as before erasing, and the data reading is performed. At the same time, by adjusting the phase of the clock of the recording system of the PLL, it is possible to prevent a decrease in the ability to reproduce unerased data even when reading the data after erasure.
[0088]
In addition, at the time of double writing, by recording the generation information of the double writing data as a set of adjacent spaces and marks, there is an effect that the data once erased can be restored.
[0089]
In addition, when writing twice, the adjacent space and mark are paired to limit the method of generating data for double writing, so that the information for generation of data for double writing can be erased once. There is an effect that the restored data can be restored.
[0090]
Further, by supplying the double writing data from the host computer, it is not necessary to have a memory for holding data, and an advantageous effect that hardware can be reduced can be obtained.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a configuration of an optical disc device according to a first embodiment of the present invention.
FIG. 2 is a block diagram showing a configuration of a PLL of the optical disc device according to the first embodiment of the present invention.
FIG. 3 is a schematic diagram of pits on an optical disc before and after erasure according to the first embodiment of the present invention.
FIG. 4 is a block diagram showing a configuration of an optical disc device according to a second embodiment of the present invention.
FIG. 5 is a diagram showing a schematic diagram of pits before and after erasure on an optical disk and KEY information of erase data in Embodiment 2 of the present invention.
FIG. 6 is a schematic diagram of pits on an optical disc before and after erasure according to a third embodiment of the present invention.
FIG. 7 is a diagram showing a schematic diagram of pits before and after erasure on an optical disc and KEY information of erased data in Embodiment 3 of the present invention.
FIG. 8 is a diagram illustrating a schematic diagram of pits before and after erasure on an optical disc and KEY information of erase data according to a fourth embodiment of the present invention.
FIG. 9 is a block diagram for explaining a conventional optical disk device.
[Explanation of symbols]
10 Optical disk
15 Spindle motor
20 Optical head
30 Amplifier circuit
40, 130 PLL
45 Synchronization (pattern) detection circuit
50 CPU
55 counter
60, 145, 300, 410, 500 encoder / decoder
70 ATIP decoder
100 memory
110, 310, 420, 540 erase data generation circuit
120, 160 selector
140, 400 binarization circuit
150, 175 Phase comparator
155, 180 Low-pass filter
165, 185 VCO
170 crystal oscillator
320 Key information storage device
510 HOST I / F
520 HOST
530 file device

Claims (14)

An optical disc device for recording or reproducing information by irradiating a light spot from an optical pickup on an optical disc,
Erasing data generating means for generating data for double writing based on data to be erased on the optical disc;
Control means for controlling the data generated by the erasure data generation means to double-write the data to be erased on the optical disc,
An optical disc device characterized by the above-mentioned. The optical disc device according to claim 1,
The erasure data generating means may have a maximum value and a minimum value of the length of the adjacent space and the mark of the data after the double writing on the disk, respectively, the adjacent space and the mark of the data before the double writing. Generating the data for double writing so as not to be different from the maximum value and the minimum value of the length of
An optical disc device characterized by the above-mentioned. The optical disc device according to claim 2,
Prior to erasure of data, the data storage means for reading and storing data to be erased from the optical disc,
An optical disc device characterized by the above-mentioned. The optical disc device according to claim 3,
The data storage means stores the data reproduced from the optical disc and binarized as it is,
An optical disc device characterized by the above-mentioned. The optical disc device according to claim 3,
The data storage means stores data reproduced from the optical disc, binarized, decoded, and error-corrected;
An optical disc device characterized by the above-mentioned. An optical disc device for recording or reproducing information by irradiating a light spot from an optical pickup on an optical disc,
Creation information storage means for recording creation information of data for double writing based on data to be erased on the optical disc;
Data reading means for reading data from the optical disk after the data has been erased, and restoring the read data based on the information stored in the creation information storage means,
An optical disc device characterized by the above-mentioned. The optical disk device according to claim 6,
Prior to erasing data, data storage means for reading and storing the data to be erased from the optical disc,
Based on data stored in the data storage means, erase data generation means for generating the data for double writing,
Control means for controlling the data generated by the erasure data generation means to double-write the data to be erased on the optical disc,
An optical disc device characterized by the above-mentioned. The optical disk device according to claim 7,
The erasure data generation means, the data on the optical disk before erasure, according to the length of the adjacent space and the mark, creates the data for double writing,
An optical disc device characterized by the above-mentioned. The optical disk device according to claim 8,
The erasure data generating means may reduce the length of the adjacent space and the mark by setting the length of the double writing so that the space is shorter by nT (n is an integer and T is a channel clock cycle) and the mark is longer by nT. Create data,
An optical disc device characterized by the above-mentioned. The optical disk device according to claim 9,
The data restoring means reads data from the optical disk after the data has been erased, and corrects the lengths of all adjacent spaces and marks so that each space is longer by nT and each mark is shorter by nT. Restore the
An optical disc device characterized by the above-mentioned. The optical disk device according to claim 6,
The creation information storage means stores the creation information in a free area of the optical disc,
An optical disc device characterized by the above-mentioned. An optical disc device for recording or reproducing information by irradiating a light spot from an optical pickup on an optical disc,
Data storage means for reading and storing data to be erased from the optical disk prior to erasing the data;
The length of the adjacent space and the mark on the disk related to the data to be erased stored in the data storage means is uniformly reduced by a fixed value mT (m is an integer, T is a channel clock cycle). Means for generating data for double writing so as to be longer,
Control means for controlling the data generated by the erasure data generation means to double-write the data to be erased on the optical disc;
The data is read from the optical disk after the data has been erased, and the length of the adjacent space and the length of the mark are corrected uniformly so that the space is longer by a fixed value mT (m is an integer, T is the channel clock cycle) and the mark is shorter. And data restoration means for restoring data.
An optical disc device characterized by the above-mentioned. An optical disc device for recording or reproducing information by irradiating a light spot from an optical pickup on an optical disc,
Data transfer means for transferring data to be erased on the optical disk from the host computer when erasing data;
Based on data sent by the data transfer means, erase data generating means for generating data for double writing,
Control means for controlling the data generated by the erasure data generation means to double-write the data to be erased on the optical disk,
An optical disc device characterized by the above-mentioned. The optical disc device according to claim 13,
Prior to data restoration, data transfer means for transferring data necessary for restoration from the host computer,
Data restoration means for restoring data read from the optical disk based on the data sent by the data transfer means,
An optical disc device characterized by the above-mentioned.

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