JPH06187744A - Draw type optical disk inspection method and device therefor - Google Patents

Abstract

PURPOSE:To provide a DRAW type optical information method and its device capable of distinguishing an error in a DRAW start position of information from an error in the information. CONSTITUTION:C1 error signals C1E and a C2 error signal C2E corresponding to 1st and 2nd Reed Solomon codes are latched in shift registers 15 and 16 by a pulse signal B to be outputted basing on the synchronous signal of an EFM frame unit. They are shifted accordingly, and the period of continuously generating a C1 error and a C2 error is measured by the EFM frame unit. Then, when the C1 error is sparsely generated by a comparing part 17, while the C2 error is continuously generated along 108 EFM frames, the occurrence of these errors is decided to be at the DRAW start position of information. By this method, the error generated in the DRAW start position and the error in recorded information can easily be discriminated, and hence and accurate inspection result can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a CIRC (Cross Inte
rleaved Reed-Solomon Code) and EFM (Eight to Fo)
The present invention relates to an inspection method and an apparatus for a write-once optical disc on which information is recorded by using modulation of urteen modulation.

[0002]

2. Description of the Related Art Conventionally, in a compact disc on which music or the like is recorded, as shown in FIG. 2, a lead-in area 2a is provided on the inner peripheral portion of the optical disc 1 and a lead-out area 2b is provided on the outer peripheral portion thereof. Data area 2c between
As such, information such as music is recorded in this data area 2c. As is well known, the lead-in area indicates that a data area next exists, and TOC (Table of Contents) information indicating the recorded contents of information in the data area is recorded, and the lead-out area ends the data area. It represents what you have done.

When recording information on these optical disks, information is recorded in the formats shown in FIGS. 3 (a) and 3 (b), for example. That is, after the information to be recorded is digitized, an error correction code by CIRC described later is added. Further, the data is converted into EFM-modulated main data and divided into 14-bit symbols, and 24
The main data MD of the symbol and the parity PT of 8 symbols are connected between each symbol via a 3 bit coupling bit CB. Furthermore, a 24-bit frame synchronization signal FS and a 14-bit sub-coding SB are added at the beginning of these.
Are concatenated via the 3 combined bits CB to form one EFM frame. A plurality of EFM frames are formed according to the capacity of information to be recorded, and 98E
One block BK is composed of an FM frame, and a synchronization signal S for identifying the head of the block in block units.
0 and S1 are recorded in the sub-coding SB.

On the other hand, although the reproduction characteristic is improved by performing the EFM modulation as described above, an error exists as a hindrance to this. This error is classified into a defect caused during manufacturing and a defect caused during handling. The size is as small as 1 bit or 2 bits (random error) and large as a few tens of bytes or more. Things (burst error) are mixed. In order to correct these errors, an error correction code is added to the digitized recording target information by CIRC.

As well known, the CIRC is a combination of two types of Read Solomon codes C1 and C2 via an interleave.
The data is dispersed over the 8EFM frame, and the parity based on the first and second Reed-Solomon codes C1 and C2 is added to this data. As a result, at the time of reproducing information, the random error is corrected by the first read Solomon code C1 and the burst error is detected. Further, the second lead Solomon code C2 is used for the first lead.
Random errors and burst errors that could not be corrected by the Dosolomon code C1 are corrected. The error that could not be corrected by the second Read Solomon code C2 is interpolated. This interpolation has a great influence on the quality of the optical disc on which information is recorded.

In the inspection device for inspecting the optical disc in which the information is recorded in the above-mentioned format, an error (hereinafter, referred to as C1) for the first and second Reed-Solomon codes C1 and C2 when the recorded information in the data area is reproduced. Error, referred to as C2 error) and interpolation,
The absolute time when these errors occur is read from the sub-coding SB, the position where the error occurs is specified, and it is used as a clue to investigate the cause of the error.

[0007]

However, in recent years,
The write-once type optical disc has become widespread, and in the above-mentioned conventional optical disc inspection apparatus, when the optical disc on which the information is additionally written is inspected, C is added at the additional write start position, that is, the joint of the information.
However, there is a problem in that the C1 error and the C2 error occur, the error and the error in the recorded information cannot be discriminated, and the accurate inspection cannot be performed.

That is, when information is recorded on the write-once type optical disc, as shown in FIG. 4, the recording of information is completed with 26 ± 1 EFM frames from the synchronizing signals S0 and S1 representing the head of the block BK. When additional recording of information follows this, recording is started from the last end position END.
Therefore, at such a joint of information, C
1, C2 error occurs.

In view of the above problems, it is an object of the present invention to provide a write-once optical disc inspection method and apparatus capable of distinguishing an error at an information write start position from an error in information.

[0010]

In order to achieve the above object, the present invention provides, in claim 1, a cross interleaved lead combining a first and a second Lead Solomon code.
Together with Do Solomon Code (CIRC), Eight to Four Modulation (EF)
In the method of inspecting a write-once optical disc in which the information modulated by the M) method and having the synchronization information inserted in a unit of an EFM frame at every predetermined period is recorded, the recording information of the optical disc is reproduced, and the synchronization information and the first information are recorded. Detecting an error for the Reed-Solomon code and an error for the second Reed-Solomon code, and detecting a continuous occurrence period of the error for the first Reed-Solomon code based on the number of times the synchronization information is detected, Based on the number of times the synchronization information is detected, a continuous error occurrence period for the second Reed-Solomon code is detected, and information is detected based on the continuous error occurrence period for each of the first and second Reed-Solomon codes. We propose a method for inspecting the write-once type optical disk that specifies the write-once starting position.

Further, in claim 2, the first and second reels are provided.
Cross interleaved combination of Dosolomon code
Along with the use of lead solomon code (CIRC), it is also modulated by the eight-to-four modulation (EFM) method, and additional information is recorded in which synchronization information is inserted in EFM frame units at predetermined intervals. Type optical disc inspection apparatus, information reproducing means for reproducing information recorded on the optical disc to be inspected as a signal, synchronization information detecting means for detecting the synchronization information from the reproduction signal, and the first signal from the reproduction signal. Of the error occurrences for the Reed-Solomon code, the first measuring means for measuring the error occurrence time for the second Read-Solomon code based on the number of times the synchronization information is detected, Second measuring means for measuring based on the number of times the synchronization information is detected, and measurement of the first and second measuring means Based on the results, we propose a test apparatus of a write-once optical disc having a postscript start position specifying means for specifying the write once start position information.

[0012]

According to the first aspect of the present invention, the information recorded on the optical disk is reproduced at the time of the inspection, and the error for the synchronization information and the first Reed-Solomon code and the error for the second Reed-Solomon code are detected. Further, based on the number of times the synchronization information is detected, a continuous occurrence period of an error for the first Reed-Solomon code is detected, and based on the number of times the synchronization information is detected, an error for the second Reed-Solomon code is detected. The continuous occurrence period of is detected. Further, the additional recording start position of the information, that is, the joint of the information is specified based on the continuous occurrence period of the error for each of the first and second Reed-Solomon codes, and is distinguished from the error occurred in the recorded information. Here, the error for the first Reed-Solomon code is
Since it is generated for each 8-bit symbol in EFM modulation, it does not occur continuously for a long period.
Since the M-modulated data is distributed and recorded over a maximum of 108 EFM frames by the combined use of interleaving, an uncorrectable error for the second Reed-Solomon code is 108E at the additional recording start position of information.
Since it occurs over the FM frame, the additional recording start position of information is specified.

According to the second aspect, the information reproducing means reproduces the information recorded on the optical disc to be inspected as a signal, and the synchronous information detecting means detects the synchronous information from the reproduced signal. Further, based on the number of times the reproduced signal and the synchronization information are detected, the first measuring means measures the continuous occurrence period of the error for the first Lead Solomon code, and the second measuring means measures the second error period. The continuous occurrence period of the error with respect to the Read Solomon code is measured, and the additional write start position specifying means specifies the additional write start position of the information based on the measurement results of the first and second measuring means. Here, the error for the first Reed-Solomon code does not occur continuously for a long period of time because it is completely decoded in 2 EFM frames, but the EFM-modulated data is a maximum of 108 EFM frames due to the combined use of interleaving. Since it is recorded in a distributed manner over the time, at the additional recording start position of information,
Since an uncorrectable error with respect to the second Reed-Solomon code occurs over the 108 EFM frame, the additional write start position of information is specified.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. In the figure, 1 is an optical disk, and 10 is an inspection device. Information is recorded on the optical disc 1 in the above-described format. In addition, the inspection device 10
Optical pickup 11, frame synchronization detection unit 12, data decoder 13, Q code decoder 14, shift registers 15 and 16, comparison unit 17, arithmetic processing unit 18, and display unit 1.
It is composed of nine.

The optical pickup 11 includes a laser diode, a photodetector and the like, and also has an optical disc 1.
Is movably arranged on the reflection surface side of the optical disc 1 and outputs the EFM-modulated signal A having a voltage proportional to the intensity of the reflected light from the optical disc 1.

The frame synchronization detector 12 receives the output signal A of the optical pickup 11 and inputs it to the data decoder 1.
3 and outputs from the signal A to the frame synchronization signal FS
And the pulse signal B is output to the shift registers 14 and 15 every time the frame synchronization signal FS is detected.

The data decoder 13 receives the EFM-modulated signal A, demodulates it, detects the errors for the read Solomon codes C1 and C2 from the reproduced signal A, and detects the errors. , And outputs the corresponding C1 error signals C1E and C2 error signals C2E at high level for a predetermined time. Further, the data decoder 13 receives the information DA of the sub coding SB from the Q code decoder 14
Output to.

The Q code decoder 14 uses the sub-coding information DA input from the data decoder 13 to obtain absolute time information T on the optical disc 1 which is currently reproducing data.
D is detected and output to the arithmetic processing unit 18.

The shift register 15 has an output of, for example, 108 bits, and has a C1 error signal C1E when the pulse signal B output from the frame synchronization detector 12 is input.
And the output data is shifted by 1 bit by the pulse signal B.

The shift register 16 has, for example, an output of 108 bits, and a C2 error signal C2E when the pulse signal B output from the frame synchronization detection unit 12 is input.
And the output data is shifted by 1 bit by the pulse signal B.

The comparison unit 17 includes shift registers 15 and 16
Monitor the output data of C2, sparse C1 error,
When the error continuously occurs over 108 EFM frames, it is determined that the error has occurred at the additional recording start position of information, and this is output to the arithmetic processing unit 18 as error information ER.

The arithmetic processing unit 18 is composed of, for example, a CPU, and the data decoder 13 outputs C1 error signals C1E and C1.
2) The error signal C2E, the absolute time information from the Q code decoder 14 and the error information ER from the comparison unit 17 are input, and the absolute time of the respective occurrence positions of the C1 error and the C2 error is obtained and displayed on the display unit 19. Along with
The display unit 19 displays whether or not the cause of the error is the additional recording start position of the information.

According to this embodiment having the above-mentioned structure,
By simply reproducing the information recorded on the write-once type optical disc 1 to be inspected, the positions where the C1 error and C2 error occur can be known by absolute time, and the cause of these errors is the additional recording of information. Since it is possible to easily know whether or not it is the start position, it is possible to immediately determine whether or not the write-once optical disc 1 is practical.

That is, as described above, the recording data is distributed over 108 EFM frames by interleaving, and the parity by the first and second Reed-Solomon codes C1 and C2 is added to this data. Further, when recording information on the write-once type optical disc, as shown in FIG. 4, sync signals S0 and S1 representing the head of the block BK are recorded.
When recording of information is completed at 26 ± 1 EFM frames from then, and when additional information is recorded subsequently, recording is started from the previous end position, so at such a joint of information, be sure to record 108 EFM frames. A C2 error occurs over time. Further, in the recorded information, the C1 error does not occur continuously over a long period of time, so the period during which the C1 error continuously occurs and the period during which the C2 error consecutively occurs are measured. This makes it possible to easily determine whether or not the cause of the error is the additional recording start position of the information.

The configuration of this embodiment is an example, and the present invention is not limited to this. For example, shift registers 15 and 1
The same effect can be obtained even if the arithmetic processing unit 18 is provided with the functions of 6 and the comparison unit 17 and the processing is performed by the program of the arithmetic processing unit 18.

[0026]

As described above, according to the first aspect of the present invention, the first and second values are detected based on the number of times synchronization information is detected.
Since the continuous occurrence period of the error for the Reed-Solomon code is measured and the additional recording start position of the information is specified based on the measurement result, the error occurring at the additional recording start position and the error in the recorded information can be easily distinguished. You can
Accurate test results can be obtained.

Further, according to claim 2, based on the number of times of detection of the synchronization information detected by the synchronization information detecting means,
The first and second measuring means measure the continuous occurrence period of the error for the first and second Reed-Solomon codes,
Since the additional recording start position of the information is specified by the additional recording start position specifying means on the basis of the measurement result, an error occurring at the additional recording start position and an error in the recorded information can be easily discriminated and an accurate inspection can be performed. It has a very excellent effect that the result can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

FIG. 2 is a diagram showing an information recording area on a compact disc.

FIG. 3 is a diagram showing a frame format at the time of recording information.

FIG. 4 is a view showing a timing at an information additional recording start position.

[Explanation of symbols]

1 ... Optical disc, 2a ... Lead-in area, 2b ... Lead-out area, 2c ... Data area, 3 ... Information unrecorded area,
10 ... Inspection device, 11 ... Optical pickup, 12 ... Frame synchronization detection unit, 13 ... Data decoder, 14 ... Q code decoder, 15, 16 ... Shift register, 17 ... Comparison unit, 18 ... Arithmetic processing unit, 19 ... Display unit .

Claims (2)

[Claims] 1. A cross-interleaved read-solomon code (CIRC) combining first and second read-solomon codes is used together with eight-to-four-modulation (EFM). A method of inspecting a write-once optical disc, which is modulated by a method and in which information in which synchronization information is inserted in units of EFM frames at a predetermined cycle is recorded, wherein the recorded information on the optical disc is reproduced, and the synchronization information and the first read An error with respect to the Solomon code and an error with respect to the second Reed-Solomon code are detected, and a continuous occurrence period of the error with respect to the first Reed-Solomon code is detected based on the number of detections of the synchronization information. Based on the number of times information is detected, the second
Detecting the continuous occurrence period of the error with respect to the Reed-Solomon code, and specifying the additional write start position of information based on the continuous occurrence period of the error with respect to each of the first and second Reed-Solomon codes. Inspection method for write-once optical disc. 2. A cross-interleaved read-solomon code (CIRC) combining first and second read-solomon codes is used together, and eight to four modulation (EFM) is used. In the inspection apparatus of the write-once optical disc in which the information which is modulated by the method and in which the synchronization information is inserted in the frame at every predetermined cycle is recorded, an information reproducing means for reproducing the information recorded in the optical disc to be inspected as a signal, A synchronization information detecting means for detecting the synchronization information from the reproduction signal; and a first period for measuring a continuous occurrence period of an error for the first Read Solomon code from the reproduction signal based on the number of times the synchronization information is detected. Means for measuring the number of consecutive occurrences of errors from the reproduced signal with respect to the second Lead Solomon code. A second measuring unit that measures based on the number of times of detection, and an additional recording start position specifying unit that specifies the additional recording start position of information based on the measurement results of the first and second measuring units are provided. Characteristic write-once optical disc inspection device.