JPH0223552A - Optical disk medium evaluating device - Google Patents

Abstract

PURPOSE:To correctly switch constant linear speeds of optical disks of MCAV and MCLV systems to each other so that reproduction of the disks can be performed stably by performing the selection of data reproducing sections and switching of the constant linear speeds to the disks of the MCAV and MCLV systems by identifying demodulated ID codes. CONSTITUTION:Data read out by an optical head 41 are supplied to a detection circuit 43 where a bit train to an ID code is detected through an amplifier 42. The bit train is inputted to the data reproducing section 51 of a test control section 5. A variable frequency oscillator (VFO) 512 freely oscillates clocks almost equal to the clock frequency of each track train group and the frequency of a clock circuit is drawn into the inputted bit train, resulting in the synchronization of clocks to the bit train. As the clocks are synchronized to the bit train, the bit train is changed to the ID code of recorded codes and selected by a computer (MPU) 2 at a selector 51. After selection, the ID code is inputted to a demodulating section 52 where the ID code is demodulated and compared with a writing pattern at a fault detecting section 53 for fault detection. Then the MPU 2 identifies the final track number and final sector number of the ID code and switches the frequency of the clock circuit to the clock frequency of the adjacent track group.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a medium evaluation device for optical discs, and more specifically, for evaluating optical discs based on extended constant angular velocity recording (MCAV) or extended constant linear velocity recording (MCLV). target,
This is an evaluation device that determines whether a preformatted identification (ID) code is [E or not, and also reads/reads a test pattern to evaluate its acceptability.

[Prior Art] Optical disks, which are frequently used as information recording media, are capable of extremely high-density information recording by providing information pits at minute intervals in tracks at minute pitch intervals. FIGS. 3(a) and 3(b) explain the recording method of the optical disc. In FIG. 3(a), the outer circumference of the optical disc 1 is set as 13, and the recording range is set between the circumference ib and IC with an appropriate radius.
A large number of tracks 1d are set within this range, and each track has equiangular sectors S! in the circumferential direction. ~Sn. Each track has a sector mark (SM), a synchronization code (VFO8Y
NC), sector information such as identification (ID) codes for sector numbers and track numbers are recorded (preformatted). When used, information data is recorded in a data area (DATA) following these sector information. Note that optical discs use a special code system that is different from general code systems, and code conversion is performed when communicating with a computer.

Recently, in order to increase the recording capacity M of optical discs, improvements or expansions have been made to recording methods for larger sizes (12 inches).

Figure 4 shows an expanded recording method in which the disk is divided into a plurality of track groups (Gl to Gm) in the radial direction, and the number of sectors is changed for each track group to move from the inside to the outside. The number of sectors is increased. There are two types of such recording methods. One is the constant rotational angular velocity (MCAV) method, which uses different clocks for track groups so that the recording density of all tracks is approximately constant. Use frequency. The other method is to keep the clock frequency constant and rotate each track group at a constant linear velocity (MCL
V) method is adopted so that the recording density of each track is almost constant. For these reasons, it is necessary to perform sector information inspection and 11'Y value 1 test of illumination/reading using a test pattern at the manufacturing stage of the optical disk.

[Problems to be solved] Conventional optical disc media evaluation devices support constant angular velocity recording with just one clock frequency; There is no switching or rotational speed change function (therefore, it is not possible to read sector information and evaluate the media performance based on the test pattern. In this case, the evaluation device does not have the optical disc rotational speed (angular velocity, linear velocity). ) has some fluctuations, so it is necessary to read sector information stably regardless of these fluctuations.

This invention provides a means for adjusting the clock frequency for each track group for (MCAV) type optical discs, and for (MCLV) type optical discs.
For each method, the linear velocity is switched, the ID code of the recorded code system that has been preformed is stably read out, and the read ID code is converted into a computer code (I Jl) to determine whether it is correct or not. do. Also,
The object of the present invention is to provide a medium evaluation device for an optical disc that converts a test pattern of a computer code into a recording code (variant, 1Jl), reads/writes it, demodulates it into a computer code, and inspects the quality.

[Means for Solving the Problems] This invention utilizes the above-mentioned (MCAV) method or (MCL) method.
V) type of optical disc media evaluation apparatus, which targets an optical disc in which each track is preformatted with an identification (ID) code such as a synchronization code based on a recording code, a track number, and a sector number. Its configuration consists of a disk drive section, a data read/write section, and a test control section, each controlled by a computer.

The data read/write unit includes an optical head that reads and writes data to the optical disk, a bit detection circuit that detects a bit string from a signal read by the optical head, and a write control unit. The test control/aiF value section includes a data image generation section that manually generates an ID code of the bit string detected by the bit detection circuit and synchronized with the clock frequency of the corresponding track group according to computer selection; a demodulator (4 demodulators) that demodulates the raw data into a computer code; a defect detector that detects defects by comparing the demodulated ID code with 10 codes preset in the computer;
and a defect location memory that stores the location of defect data.

In the above, the write pattern from the test pattern generator is modulated into a recording code by the write control unit, and written/read from the data part of the optical disk, and the read pattern is demodulated into computer code by the demodulation unit, A defect detection unit detects a defect by comparing it with the written pattern, and stores the position of the defect data in a defect position memory.

In Article J-, the selection of the above-mentioned data reproduction for (MCAV) type optical discs, and (MCLV)
For optical discs of this type, switching of the constant linear velocity corresponding to a track group is performed by identifying the demodulated II) code (track number, sector number) in a computer.

[Function] In the optical disk medium evaluation apparatus of the present invention having the above configuration, the ID code preformatted in the recording code format is detected as a bit string by the data M reading/reading section, and test control *, ? 'l'4
In the case of the fim+, OITE, (MCAV) system, a computer reproduces the I[') code of a bit string synchronized with the clock frequency of the track group in question in the data recording section. In the case of the (MCLV) method, the computer switches the rotation at a constant linear velocity for the track group to generate the IY code in the same way. The reproduced data is demodulated into an ID code, which is a computer code, in the demodulation section, and the defect detection section determines whether the data is correct or not by comparing it with an II) code preset in the computer. In the case of a test pattern, an old pattern in a computer code format from a test pattern generator is modulated into a recording code format and written/read, and the read pattern is demodulated into a computer code in a demodulation section. Similar comparisons are made. The position of data determined to be defective is stored in a defective position memory.

Next, regarding the selection and switching of the data FrG generation section with respect to the clock frequency of the track group described above, 1. Using the ID code obtained in this way, the number of the last track in the track group and the number of the last sector of that track can be identified and switched. (MCLV)
For the system, the above numbers are similarly identified and IJJ switching of constant linear velocity is performed. Note that the transition between track groups can also be performed by skipping adjacent track groups, depending on the order set in the track computer.

[Embodiment] FIG. 1 shows an optical disc medium 1 according to the present invention.・) This shows the block configuration in an embodiment of the shelf device. To explain the configuration and operation of each part using diagrams, the disk drive f
The motor driver 32 of f1s3 is programmable, and its rotational speed is specified by the computer 2. Current from this motor driver 32 is supplied to the spindle motor 3I to rotate the optical disk to be scanned 4Ijl mounted on the spindle. In the data reading/old storage section 4, the optical head 4
1 is inserted corresponding to the optical disc, 7M of data is read out, and the read data is amplified by n.
(AMP) 42 adjusts it to an appropriate level, and a bit detection circuit 43 detects the bit string for the ID code. The bit detection circuit is a normal one consisting of an AGC, an LPF1 differentiation circuit, and a binarization circuit. In the test control unit 5, the above bit string is stored in the data itG generation unit 51.
to use human power. The data ltt generation section is provided with m sets of clock circuits 5 and 01 variable frequency oscillator (VF'0) 512, which is the same number as the track groups of the (MCAV) method, and the clock oscillation circuit is approximately equal to the clock frequency of each track group. The clock is freely oscillating. The frequency of the clock circuit is drawn into the input bit string by the corresponding variable frequency oscillator, and the clock is synchronized therewith. By synchronization, the bit string is made into the ID code of the recording code, and is further selected by the computer in the selector 513 and sent to the demodulator 5.
2 and demodulated into computer code. The demodulated II) code is compared with the ID code set in the rth computer in the defect detection section 53 to determine whether it is correct or not, and if there is a defect, its location is stored in the defect location memory 54.

Next, evaluation tests using test patterns will be described.

A test pattern generator 55 generates an appropriate test pattern of computer code, which is modulated into a recording code pattern by the write control section 44, and is then modulated by the optical head 41.
The data is written into the data section of the optical disc 1. This is read out and adjusted to an appropriate level by amplifier 42. In this case, the read data is directly demodulated +'
The signal is transferred to the i552 and demodulated into a computer code pattern, and the defect detection section 53 compares it with the S writing pattern to detect defects. The following operations of the defect detection section 53 and the defect position memory 54 can be performed within the computer 2 by program processing.

Next, we will discuss the selection and switching of the clock in the data reproduction section (data reproduction section in the above) for the above track group. The final track number and the number of its final sector are separated by 11'a by the computer, and when the rear end of the data area of the final sector is detected, the clock frequency is switched to that of the adjacent track group.In this case, the clock frequency of the final track, sector In addition to each number, the identification is by a sector mark (see Figure 3 (b) IJ).
This is done in combination with the number of detected objects.

According to the evaluation apparatus of the present invention, it is also possible to perform the 1) devaluation test using the (MCAV) method on an optical disc using the (MCLV) method.

Figure 2 shows a computer flowchart for clock switching. First, the σj switching sequence is started, and when the sector number becomes final, the rear end of the data area is detected and the adjacent track group is switched. Against Kuro, Ri is replaced with IJJ■. Then, when a sector mark is detected, it is assumed that the switching has been done normally, and I) Detection of code or information data N! rll determination is performed ■, and is repeated until the number of switching becomes m, which is the same as track J1″r. If no sector mark is detected in ■, the clock is switched +17 degrees ■, and a sector mark is detected. When ■, the process moves to the above-mentioned track detection ■.If the sector mark is still not detected in ■ and the number of switching is still m, the process returns to ■, and the clock is switched again.In ■, the number of switching is m. If it has reached, it is assumed that none of the switching has been performed normally, and the error processing [phase] is performed and the process ends. Hereinafter, the 1゛V value test of one optical disk is completed by H. .In addition, (MC
The constant linear velocity switching for the LV) method is also the same as described above.

[Effects of the Invention] As is clear from the explanation in 1-1, the optical disc medium evaluation apparatus according to the present invention is capable of switching clock frequencies corresponding to track groups for (MCAV) or (MCLV) type optical discs. , or the constant linear velocity υJ is accurately changed, and data can be stably reproduced due to the frequency pull-in effect of data + 1 generation even with slight fluctuations in the rotational speed of the optical disk. In addition, evaluation tests can be performed completely by performing the necessary Henken demodulation between the computer code format and the recorded code format for each track's [II] code or test pattern, making it a highly advanced system. The effects of this contribution on media evaluation of optical discs are significant.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the optical disk medium evaluation apparatus according to the present invention, FIG. 2 is a partial flowchart of computer processing for FIG. 1, and FIG. 3(a)
and (b) is an explanatory diagram of tracks and sectors of an optical disc, and sector information set on the tracks, and FIG. 4 is an explanatory diagram of extended recording methods (MCAV) and (MCLV). ■...Optical disc, la...Disk outer circumference, lb, lc...Circumference, ld...Track, 1e...Track J? L 2-...Computer, 3...Disk drive section, 31...Spindle motor, 32...Motor driver, 4...Data reading! 1. F/A included? J<41...Optical head, 42...Amplifier, 43...Bit detector, 44...
...Infiltration control section, 5...Test control fist evaluation section, 51.
...Data reproduction section, 511...Clock circuit, 512
...Variable frequency oscillator, 513...Selector, 52.
...? jJ tuning section, 53...defect detection section, 54.
...Defect position memory section, 55...Test pattern generator, ■~■...Flowchart number.

Claims (3)

[Claims] (1) An expanded standard that divides a large number of tracks set on a disk surface into multiple track groups, divides each track group into a different number of sectors, and uses a different clock frequency for each track group. Angular velocity recording (MCAV) method,
Alternatively, extended constant linear velocity recording (MCL) uses a constant clock frequency to record information data at a constant linear velocity (hereinafter simply referred to as constant linear velocity) that differs for each track group.
V) In the evaluation test of the optical disc of the method, identification (ID) codes such as a synchronization code, track number, and sector number according to the recording code system of the optical disc (hereinafter simply referred to as recording code) are recorded on each track. It targets the preformatted optical disc, and includes a disc drive unit that rotates the optical disc and is controlled by a computer, an optical head that reads/writes data to/from the optical disc, and an optical head that reads/writes data to/from the optical disc. A data read/write section includes a bit detection circuit that detects a bit string from a signal detected by the head, and a write control section, and the bit string detected by the bit detection circuit is input, and the computer selects the corresponding track. a data reproducing unit that reproduces an ID code synchronized with the clock frequency of the group; an ID demodulating unit that demodulates the reproduced data obtained by the data reproducing unit into an ID code of a computer code system (hereinafter simply referred to as computer code); A test control/evaluation section comprising a defect detection section that detects defects by comparing the demodulated ID code with an ID code preset in the computer, and a defect position memory that stores the position of the detected defect data. An optical disc medium evaluation device comprising: (2) In the above, the writing control unit modulates the write test pattern from the test pattern generator into the pattern of the recording code and writes/reads the data part of the optical disc, and the read test pattern is Demodulating the pattern into a pattern of the computer code in the demodulation section, and detecting defects by comparing it with the written test pattern in the defect detection section,
2. The optical disc medium evaluation apparatus according to claim 1, wherein the position of the defect data is output and stored in the defect position memory. (3) In the above, the selection of the computer for the data reproducing unit on the (MCAV) type optical disc or the switching of the constant linear velocity for the track group on the (MCLV) type optical disc is performed by the computer code in the demodulation unit in the computer. 3. The optical disc medium evaluation apparatus according to claim 1, wherein the optical disc medium evaluation apparatus performs the evaluation by identifying an ID code (track number, sector number) demodulated.