JPS6059540A - Recording and reproducing device of optical information - Google Patents

Abstract

PURPOSE:To test recording state simultaneously with recording by comparing a modulated signal output with a reproduced signal output during the recording and counting up and deciding inconsistent outputs. CONSTITUTION:A modulated signal output 100 from a digital modulating circuit 4 is inputted to a semiconductor laser driving circuit 5 and a comparator 17 and optically recorded in an optical recording disc 9. Light reflected by the disc 9 during the recording is converted into an electric signal by an optical head 6 and the electric signal is inputted to a waveform equalization circuit 13 as a reproduced signal 104. A reproduced signal output 105 from the circuit 13 is a signal including the defect of the disc 9 and compared with the output 100 by the comparator 17 and its inconsistent output 107 is inputted to a counting/deciding circuit 18. The circuit 18 counts up the output 107 and decides whether an error generated in the recording can be permitted or not.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an optical information recording and reproducing device for recording and reproducing data on an optical recording disk, and particularly for detecting errors that occur in an optical recording disk while recording data on an optical recording disk. The present invention relates to an optical information recording and reproducing apparatus that can confirm recording on an optical recording disk and verify the accuracy of recording.

Conventional configurations and their problems Optical recording disk memory, which is seen as a promising high-density, large-capacity memory, requires error control technology such as error detection and error correction to overcome the low error rate of optical recording disks. It is.

Optical recording disks usually have optically detectable guide tracks such as guide grooves in order to achieve high track density, and a laser beam focused to a diameter of about 1 μm is applied to the recording layer formed on the guide tracks. The data is recorded by irradiating the beam and making a hole or causing a change in reflectance. The recorded data is read as changes in reflected light by irradiating the optical recording disk with sufficiently weak laser light.

Since the recording dot and track pitches are approximately 1 μm, various changes may occur depending on the manufacturing process of the optical recording disk - formation of guide tracks, manufacture of replica disks, deposition of recording material, formation of the protective layer - or the environment in which the optical recording disk is used. Defects, dust, and scratches occur, resulting in dropouts in the playback signal.

These dropouts vary widely, with burst-like dropouts and random dropouts occurring to the same degree. As a result, the raw error rate of optical recording disks is said to be 10 to 1o, compared to the raw error rate of 10-9 to 1o-12 for magnetic disks, which are typical conventional recording media. The current situation is very bad.

FIG. 1 on page 6 is a conventional example of a configuration diagram of an optical information recording/reproducing apparatus. In Figure 1, 1 is a data buffer 7 memory for temporarily storing data to be recorded, and 2 is an error detection/memory.
An error control circuit for correction; 3 a sector buffer memory for storing encoded data to be recorded on the optical recording disk 9; and 4 a digital modulation circuit. 5 is a semiconductor laser drive circuit, 6 is an optical head, 7 is a head amplifier,
8 is a linear motor that moves the optical head 6 and head amplifier 7 at high speed. 9 is an optical recording disk, and 10 is a disk motor that rotates the optical recording disk 9.

Reference numeral 11 denotes a focus/tracking servo circuit that focuses the output beam of the optical head on a predetermined track of the optical recording disk 9 and follows it. 12 is a linear motor drive circuit, and 13 is a waveform equalization circuit for correcting the frequency of the reproduced signal output from the head amplifier 7 to improve waveform deterioration. 1
Reference numeral 4 denotes an address reproducing circuit that demodulates address information recorded on the tracks of the optical recording disk 9. 16 is a Zoro page digital demodulation circuit, and 16 is a control section for the entire apparatus.

Next, the operation shown in FIG. 1 will be explained.

A sector format disk in which the optical recording disk 9 has tracks divided in advance into a plurality of sectors will be explained. Data corresponding to the sector capacity is input to the data buffer 1. The sector capacity of ξ is 256B (bytes) to 10
It is 24B. The input data of the data buffer 1 is input to BCH (Boss-Chau) by the error control circuit 2.
dhur i -Hocquenghen) code, R
An error detection and correction code such as an S (Reed Solomon) code is stored in the selector buffer 3 as encoded data consisting of a generated check code.

The selector buffer 3 is a temporary memory to be recorded in a sector of the optical recording disk 9, and is used for interleaving burst errors occurring on the optical recording disk e to randomly distribute them to each code word in the encoded data. It has the function of "Being". The encoded data in the sector buffer 3 is input to a digital 7 page modulation circuit 4 in a mixed manner, and is modulated into a signal suitable for optical recording. Modulation signal output 100 of digital modulation circuit 4
The semiconductor laser drive circuit 5 modulates the semiconductor laser of the optical head 6 and outputs a modulated signal 10 to a predetermined sector.
Record 0.

Track access to the optical recording disk 9 is performed by reading the address output 101 of the address reproduction circuit 14, calculating the difference between the current address and the target address in the control section 16, and controlling the linear motor 8 with the linear motor drive circuit 12. It will be done.

Further, the detection of the designated sector is performed by the control unit 16 comparing the sector address included in the address recorded in advance at the beginning of each sector of the optical recording disk 9, and the write gate signal 102 and the reproduction gate signal 103 are detected. generated by the digital modulation circuit 4. Digital demodulation circuit 15
input to control each operation.

The head amplifier 7 amplifies a weak reproduction signal obtained by photoelectrically converting changes in reflected light from the optical recording disk 9 using a photoelectric conversion element built into the optical head 6. The reproduced signal 104 amplified by the head amplifier 7 is frequency-corrected by the waveform equalization circuit 13 and binarized to become a reproduced signal output 105. The reproduced signal output 105 is demodulated by the digital demodulation circuit 15, deconfused as reproduced encoded data, and temporarily stored in the sector buffer 3.

The reproduced encoded data is checked for errors in the error control circuit 2, and if an error is detected, it is corrected and stored in the data buffer 1.

In FIG. 1, to check whether data has been recorded correctly, the recorded sector is played back and the error control circuit 2 detects an error, or the data buffer 1 is used to check whether the input data and the playback data are Verification through data comparison is necessary.

Since the raw error rate of optical recording disks is as low as 1σ4 to 10'5, powerful error detection and correction codes are used, and a time delay of several 100 μB to several rns is involved in decoding reproduced encoded data. For this reason, nine pages are required to perform the above-mentioned recording verification on a sector format disk, and a rotational wait for verification occurs, making it impossible to perform continuous sector recording. Waiting for disk rotation causes a problem in that the data transfer speed to the data buffer 1 is significantly reduced.

OBJECTS OF THE INVENTION The present invention is directed to errors occurring during recording on optical recording discs, such as dropouts of optical recording discs.

Detects in real time recording defects caused by out-of-focus of the optical head's light beam or track-following errors, recording defects due to semiconductor laser defects, errors occurring in the electrical circuit system, etc., and verifies the state of recording on the optical recording disk. The object of the present invention is to provide an optical information recording/reproducing device that enables accurate data recording.

Structure of the Invention The present invention involves photoelectrically converting light reflected from an optical recording disk when recording a modulated signal output obtained by modulating encoded data in which an error detection and correction code is added to the data to be recorded in a digital modulation circuit on an optical recording disk. Detecting errors that occurred during recording by comparing the reproduced signal output and the modulated signal output for 10 pages;
The recording state is verified by determining whether or not it is within the error correction capability of the error detection and correction code.

DESCRIPTION OF THE EMBODIMENT FIG. 2 is a block diagram of an embodiment of the optical information recording/reproducing apparatus of the present invention.

1 to 16 and 100 to 106 correspond to the numbers in FIG. 1, and the same numbers are the same.

17 is a comparison circuit that compares the modulated signal output 100 and the reproduced signal output 105; 18 is a mismatch output 10 of the comparison circuit 17;
This is a counting/determination circuit that counts the errors that have occurred during recording detected by 7 and determines whether or not the errors are permissible. 1
06 is a modulation clock for the modulation signal output 1oo.

The data input to the data buffer 1 is given an error detection and correction code by the error control circuit 2, and is stored in the sector buffer 3 as encoded data.

To record on the optical recording disk 9, the encoded data stored in the sector buffer 3 is read out in an intersecting manner and output, modulated by the digital modulation circuit 4, and outputted as a modulated signal 1o○ by the semiconductor laser drive circuit 6. and comparison circuit 17
is input. The modulated signal output 100 is optically recorded on the optical recording disk 9 by the optical head 6 .

The light reflected by the optical recording disk 9 while recording the modulated signal output 100 is converted into an electric signal by the photoelectric conversion element of the optical head 6, amplified by the head amplifier 7, and inputted to the waveform equalization circuit 13 as a reproduced signal 104. Ru.

This reproduction signal 104 is generated by direct defects of recording dots due to defects such as scratches and dust on the tracks of the optical recording disk 9;
Alternatively, changes in the amplitude of the reproduced signal 104 due to defocusing of the recording light beam due to the influence on focus/tracking servo, S/N deterioration due to tracking deviation, jitter of recording dots, etc. are reflected. The reproduced signal 104 is frequency-corrected and binarized by the waveform equalization circuit 13.

This reproduced signal output 105 is a signal containing defects in the recording disk 9.

Comparison circuit 17 compares this reproduced signal output 105 with modulated signal output 100 for consistency. The comparison is performed at the timing of the modulation clock 106 and is input to the determination circuit 18 as a mismatch output 107. The counting judgment circuit 18 has a discrepancy output 1
07, and in cooperation with the control unit 16, it is determined whether the error that occurred during recording is tolerable or not. The determination of this permissible error depends on the ability of the error control circuit, but it is set to at least below the error correction ability.

FIG. 3 shows an embodiment of the comparator circuit 17 and the count determination circuit 18.

19. 20 and 22 are latch circuits, 21 is exclusive off (
EOR), 23 is a pulse number counter, and 24 is a pulse width counter.

In FIG. 3, the modulated signal output 100
is latched by the modulation clock 106.

Similarly, the reproduced signal output 105 is latched by the modulation clock 106 in the latch circuit 2o. The outputs of the latch circuits 19 and 20 are compared by exclusive OR 21. The output of exclusive OR 21 is latched in latch 132 to prevent glitches. Therefore, when a mismatch between the inputs is detected by the exclusive OR 21, the mismatch output 1o of the latch circuit 22 is enabled. This mismatch output 107
is input to the pulse number counter 23 and pulse width counter 24. The pulse number counter 23 has a discrepancy output 107
The number of random errors is counted from , and the result is sent to the control unit 1.
Notify 6. The pulse width counter 24 detects the length of a burst error, and similarly notifies the control unit 16 of the length. The control unit 16 determines whether the error can be corrected by the error control circuit 2 based on the number of random errors and the burst error length.

FIG. 4 shows another embodiment of the present invention. FIG. 5 shows the format and control signal of the modulated signal output 1oO to the sector of the optical recording disk to which FIG. 4 is applied.

4 and 5, 4. 5. 13. 17° and 18 represent the same blocks as the same numbers in Figure 2, and 10
0.105, 106, and 107 also represent the same signal.

14 Page 25 is a comparison gate signal generation circuit, 108 is a modulation signal output enable signal, and 1o9 comparison gate signal.

The modulated signal output 100 includes a synchronization pattern 11o for facilitating clock recovery during reproduction, and data marks 111. Data 112 and error detection and correction code 1
Consists of 13.

The comparison gate signal generation circuit 25 generates a comparison gate signal 109 that covers the data mark 111 with the modulation signal output enable signal 108 and the modulation clock 106. Comparison circuit 17 compares modulated signal output 100 and reproduced signal output 105 while comparison gate signal 109 is valid, and outputs the result.

In the modulated signal output 100 shown in FIG. 6, if the data mark 111 is incorrectly detected or cannot be detected due to an error, a large burst error will occur in the data portion. Therefore, the count determination circuit 18 of FIG. 4 determines that recording is defective when the count of 15 errors exceeds the number of pit errors allowed by the data mark detection logic.

FIG. 6 is a block diagram of another embodiment of the present invention, which is applied when the encoded data shown in FIG. 7 is interleaved and recorded.

Figure 7 shows four rows of (n, k) codewords with n code lengths, each with r check codes added to the data code. recorded in the row direction.

Since the burst errors occurring in the optical recording disk 2 occur in the row direction in FIG. 7, the code words in each column are randomized. For example, Reed of GF(2) as codeword
If the Solomon code is configured with r = 4 symbols (symbol - 8 bits), the code distance will be 6, so it is possible to correct errors up to 2 symbols. therefore,
Burst errors up to 2xl symbols can be corrected in the entire sector. However, when a random error occurs, a maximum of 2×7 symbols can be corrected if uniformly random, but in the worst case, if 3 symbol errors are concentrated in the same code word, it cannot be corrected.

FIG. 6 shows the verification of the record by detecting the concentration of errors in one code word.

In Fig. 6, 4, 17, 100, 105°, 106.
107 and 108 are the same as the same numbers in FIGS. 2 and 4.

26 is a demultiplexer, 27 is a dinterleave counter, 28 is a counter array, and 29 is a determination circuit.

The modulation signal output 100 and the reproduction signal output 105 are provided by the comparison circuit 1.
7, and an error is output as a mismatch output 107. The mismatch output 107 is sent to the seventh
It is distributed to the input of a counter array 28 provided in one-to-one correspondence with one column of code words in the figure, and the number of errors for each code word is counted. The dinterleave counter 27 counts the modulation clock 106 using the modulation signal output enable signal 108 and generates the address signal 114 of the code word column to which the mismatch output 1070 currently being compared belongs.

The determination circuit 29 determines whether the counted value of the counter array 28 exceeds the number of correctable codes of the code word (17), and if even one of the counter arrays 28 exceeds the number, it is determined that there is a recording defect.

The sector recorded as described above is determined to be defective and is re-recorded in another unrecorded sector.

In addition to the effects of the invention, the present invention compares the modulated signal output and the reproduced signal output during recording, and counts and determines the mismatched outputs.
Detection of errors that occur during recording, especially error detection using special identification signals that are susceptible to errors, or detection of the presence or absence of worst-case random errors that exceed the error correction ability of code words that are recorded in a mixed manner. This enables verification of information and recording at the same time.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the conventional configuration of an optical information recording/reproducing device, FIG. 2 is a block diagram showing the configuration of an embodiment of the optical information recording/reproducing device of the present invention, and FIG. 3 is a block diagram of the same embodiment. Block diagram of the comparison circuit and counting judgment circuit in 4th
The figure is a block diagram showing the configuration of another embodiment 18 of the present invention, FIG. 6 is a diagram showing the format of the modulated signal output and the control signal to which FIG. 4 is applied, and FIG. Block 7 showing the configuration of another embodiment
The figure is a diagram showing an arrangement of code words when encoded data to which FIG. 6 is applied is recorded in a mixed manner. 1... Data buffer, 2... Error control circuit, 3... Sector buffer, 4...
...Digital modulation circuit, 6...Semiconductor laser drive circuit, 6...Optical head, 7...
Head amplifier, 9... Optical recording disk, 13.
... Waveform equalization circuit, 16 ... Digital demodulation circuit, 16 ... Control section, 17 ...
Comparison circuit, 18...Counting judgment circuit, 26...
... Comparison gate signal generation circuit, 26 ... Demultiplexer, 27 ... Dinterleave counter, 28 ... Counter array, 29 ...
...Judgment circuit, 100...Modulation signal output, 1o
6... Reproduction signal output, 106... Modulation clock, 1o9... Comparison gate signal. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 3
Figure 4 Figure 5

Claims (1)

[Scope of Claims] (1) An optical recording disk, a buffer means for temporarily storing input data, a means for adding an error detection and correction code to the input data, and a modulation means for modulating the input data to which the error detection and correction code has been added. , means for recording the modulated signal output of the modulating means on a predetermined track of the optical recording disk using a laser light source. means for receiving and photoelectrically converting reflected light from the optical recording disk; demodulating means for demodulating the reproduced signal output of the photoelectric converting means; detecting and correcting errors occurring in the reproduced data output of the demodulating means using the error detection and correction code; means for storing the corrected reproduction data in the buffer means; and means for comparing the modulation signal output of the modulation means and the reproduction signal output of the photoelectric conversion means during recording on the optical recording disk; An optical information recording/reproducing apparatus comprising means for determining whether the error detection and correction code is within the correction capability of two pages based on the mismatch output of the comparison means. (2. An optical information recording/reproducing device as set forth in claim 1, characterized in that the corresponding input data is re-recorded by the output of the determining means. (3) As set forth in claim 1 , an optical information recording and reproducing device characterized in that the comparing means compares the modulated signal output and the reproduced signal output at the timing of the modulation clock of the modulating means. (4) Claim 1 or 2. The optical information recording/reproducing device according to claim 3, wherein the operation of the comparison means is controlled by a gate signal indicating a specific section of the modulated signal output. (5) In claim 4, the modulated signal output is clocked A final synchronization pattern to facilitate reproduction, and an identification signal indicating the end of the synchronization pattern.Comprised of the input data and its error detection and correction code, the gate signal is output in an interval including at least the identification signal. An optical information recording/reproducing device characterized by: 3-Signed (6) Claims 1 or 3, wherein the modulation signal is modulated by interlacing code words obtained by error detection and correction coding of input data. 1. An optical information recording and reproducing apparatus, characterized in that the optical information recording and reproducing apparatus generates a code word and counts mismatch outputs of a comparing means for each code word.