JPH0520813B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to replacement of defective sectors in an optical disk recording and reproducing apparatus that optically records and reproduces information using a laser beam or the like.

BACKGROUND TECHNOLOGY Substitution of defective sectors in a conventional optical disk recording/reproducing apparatus is disclosed in Japanese Patent Laid-Open No. 57-53844.

FIG. 5 shows this conventional device, in which a reproducing optical head 20 and a recording/reproducing head 21 provided on the same base 22 scan the guide track of the optical disk 1 and run the reproducing head. optical head 20
detecting the presence or absence of a defect in the guide track, writing a defective mark on the corresponding sector of the guide track using the recording/reproducing optical head 21, and writing a new ID in the area following the defective sector ID section.
Alternatively, it has been disclosed that a special subdivided sector is created outside the disk and bad sector information is rerecorded there. In particular, in the case of an optical disk that has been treated with defective marks in advance, data is recorded in advance by scanning the sectors with the reproducing optical head 20 to check for the presence or absence of defective marks. The sector is replaced by a subdivided sector provided on the outer periphery of the disk.

Problems to be Solved by the Invention However, the above configuration requires two optical heads, the reproducing optical head 20 and the recording/reproducing optical head 21. If only one recording/reproducing optical head is used, a waiting time of at least two rotations is required to process the above-mentioned defective sector, resulting in a problem of slow access time.

Furthermore, since the reproducing optical head and the recording/reproducing optical head are separated by a distance l on the track, data and defective marks overlap at a portion. This poses a problem in that it becomes difficult to detect a defective mark from the defective sector during data reproduction.

SUMMARY OF THE INVENTION In view of the above, it is an object of the present invention to provide an optical disk recording/reproducing apparatus that simultaneously detects bad sectors during writing and makes it easier to detect bad sectors during playback.

Means for Solving the Problems The present invention provides an optical head, a data modulation/demodulation means, a defective sector detection means, and a defective mark signal consisting of a pulse train having a pulse width sufficiently longer than the maximum signal inversion interval of the data modulation output. A defective mark recording means that generates and records data, a slice level generating means that generates two slice levels, and compares reproduced signals at different slice levels to record and record data.
The present invention is an optical disk recording and reproducing apparatus that includes a defect detection means for checking the presence or absence of a defective mark during reproduction, and a sector replacement means for replacing a defective sector with a normal sector.

Effects According to the above-described configuration, the present invention uses the defective sector detection means to check for the presence or absence of a defective sector before using the optical disk, records a defective mark on the defective sector using the defective mark recording means, and generates a slice level. The means is to set the slice level Vf higher than the recorded signal amplitude of the reproduced signal during data recording.
is applied to the defective mark generation means to check the presence or absence of a defective mark signal, and if a defective sector signal is detected from the sector, the sector is alternatively recorded as a normal sector, and when data is reproduced, approximately half of the reproduced signal is recorded. The slice level Vo of is applied to the defective mark generating means to check the presence or absence of a defective mark signal in the sector, and if a defective sector signal is detected, data is reproduced from the alternative sector.

Embodiment FIG. 1 shows a block diagram of an optical disk recording/reproducing apparatus according to an embodiment of the present invention.

In FIG. 1, 1 is an optical disk, 2 is a motor, 3 is an optical head for recording and reproducing, and 4 is an optical head 3.
5 is a reproduction circuit that amplifies and equalizes the waveform of the minute reproduction signal 100 from the optical head 3; 6 is a data modulation/demodulation circuit that digitally modulates and demodulates the data 170; 7 is a defective one. 8 is a mark generation/detection circuit, 8 is a defect detection circuit, and 9 is a CPU that controls the entire device.

The operation of the optical disc recording and reproducing apparatus of this embodiment configured as described above will be described below.

First, before using an optical disk, a check is made to see if there are any defects in sectors, and a defective mark is written in the defective sectors.

The CPU 9 seeks a target track on the optical disk 1, which is rotating the optical head 3 at a constant speed by the motor 2. The optical head 3 irradiates the optical disc 1 with uniform light that does not cause recording, receives the reflected light, and outputs a reproduced signal 100. The reproduction signal 100 is amplified by the reproduction circuit 5, passed through a filter with a frequency band suitable for disk defect detection, and input as a signal 120 to the defect detection circuit 8. In the defect detection circuit 8, among defects such as drop-outs and drop-ins included in the reproduced signal 100, those exceeding a predetermined slice level are taken into the CPU 9 as a drop-out signal 130, and depending on the length and number of defects, it is determined whether or not they are bad sectors. is determined.

If it is determined to be a bad sector, the CPU 9 sends an activation signal 140 to the bad mark generation/detection circuit 7. The defective mark generation/detection circuit 7 outputs a defective mark signal 150 to the recording circuit 4, and records a defective mark in the corresponding sector.

Sector inspection is performed by repeatedly checking for sector defects and recording defective marks in defective sectors.

Next, the operations for recording data and reproducing data-recorded sectors will be described below.

The data 170 to which the error correction code has been added is
The data is digitally modulated by the data modulation/demodulation circuit 6. The digitally modulated modulation signal 180 is applied to the recording circuit 4, modulates the laser of the optical head 3 at the recording power level, and irradiates the optical disk 1 with the modulated signal 180. At this time, the light reflected by the optical disk is the reproduced signal 1
It is detected as 00 and processed by the reproduction circuit 5, and the signal 1
The signal 90 is input to the defective mark generation/detection circuit 7, and the presence or absence of a defective mark is checked. When a defective mark is detected, an interrupt signal 200 is output to the CPU 9. Using this interrupt, the CPU 9 waits for the data modulation/demodulation circuit 6 to complete writing data to the corresponding sector, switches control to the alternative sector processing routine, and executes the allocation of the alternative sector and rewriting of the data to the alternative sector. do.

In data reproduction, the reproduction signal 100 is divided by the reproduction circuit 5 into a signal 210 for data reproduction and a signal 190 for detecting defective marks. The signal 210 is demodulated by the data modulation/demodulation circuit 6 and output as data 170. The signal 190 is input to the defective mark generation/detection circuit 7 in the same way as when recording data, and the presence or absence of the defective mark is checked.

Signal 220 represents sector write/play mode control and the status of each circuit.

FIG. 2 is an external view of the optical disk 1 of this embodiment. The guide track 11 is divided into a plurality of sectors 10 based on sector ID portions and IDs. sector ID section,
The ID is a sector identification section consisting of address information such as a track address and a sector address. The rest is a data field section for recording data.

FIG. 3 is a diagram of operating signal waveforms in the embodiments of FIGS. 1 and 2. FIG. 3 shows the waveforms of a defective bad sector and a good sector. The numbers of each signal correspond to those in FIG. FIGS. 3a and 3b show the waveforms of a bad mark signal 150 written into a bad sector and a reproduced signal 100 from the bad sector in which the bad mark signal 150 was written. The defective mark signal 150 is a pulse train having a width sufficiently longer than the data recording dot interval. FIG. 3c shows the modulation signal 180
It is. FIG. 3d shows the waveform of the reproduced signal 100 from the optical head during data writing. In the mark portion of the defective mark signal 150a recorded in the defective sector, the reflectance of the recording layer of the optical disc is changed compared to the unrecorded portion. This change is in the form of an increase or decrease in reflectance, ranging from 10% to 10% before and after recording.
This results in a reflectance change of several tens of percent. Therefore, the amount of reflected light reflected at the defective mark portion 150a is greater than the amount of reflected light from areas other than the defective mark portion, and the reproduction signal 10
Uneven waveform 15 corresponding to a pulse train with a defective mark at 0
yields 0b. The voltage Vf is a slice level of the defect detection circuit 8, and is set to a level at which only the defect mark portion of the waveform 150b is detected when the amplitude of the modulated signal 180 is greater than or equal to that detected in the reproduced signal 100.

FIG. 3e shows signal 230 detected from waveform 150b, envelope detected and signal 240.
is obtained.

Figure 3g shows the reproduction signal 100 after data recording is completed.
This is the waveform of The modulation signal 180 is not recorded in the defective mark portion 150c, and the state shown in FIG. 3b is preserved. The defective mark signal 150c is sliced at a slice level Vo that is approximately half the amplitude of the reproduced signal 100, and then subjected to envelope detection.
The envelope signal 240 of FIG. 3h is obtained.

FIG. 4 is a block diagram of one embodiment of the defective mark generation/detection circuit 7 of the present invention.

In FIG. 4, 12 and 13 are comparators;
Comparison voltage sources 14 and 15 provide slice levels V _f and V _p , respectively. 16 is an AND circuit,
17 is an OR circuit, 18 is an envelope detection circuit composed of a retrigger type mono multivibrator, etc., 19 is a serial port, 30 is a delay circuit, 3
1 is a high frequency pulse generation circuit, and 32 is an adder circuit.

The operation of the defective mark generation/detection circuit 7 configured as described above will be explained below.

Serial port 19 is CPU 9 activation signal 140
In response, a low-frequency pulse train signal 300 that is sufficiently wider than the maximum inverted pulse width of the modulation signal 180 is output, and a signal 320 delayed by a certain time T in the delay circuit 30 is outputted from the high-frequency pulse generation circuit 31.
0 and an adder circuit 32 to generate a defective mark signal 150 shown in FIG. 3a.

As the serial port 19, for example, a UART LSI for asynchronous data communication is used.

During data recording, the output 190 of the reproducing circuit 5 is binarized by the comparator 12. threshold
V _f is the reproduced signal 100 as shown in Figure 3d.
The amplitude of the modulated signal 180 is set to a level that slices the defective mark portion of the waveform 150b.
The output of the comparator 12 passes through the OR circuit 17 and outputs a signal 230 shown in FIG. 3e.

At this time, the output of the comparator 13 is not sent to the OR circuit 17 because the read mode signal 220 is set to be invalid in the AND circuit 16.
The envelope of the high frequency component of the signal 230 is detected by the envelope detection circuit 18 and converted into an envelope signal 240 shown in FIG. 3f. The envelope signal 240 is input to the serial port 19,
An interrupt signal of 20 is generated every time a predetermined number of pulses are input.
Outputs 0 to cpu9.

Next, the operation during data reproduction will be explained.

In the present invention, defective sectors are initialized, and during recording, modulation signals are recorded in defective sectors in which defective marks are recorded. Therefore, during playback,
The reproduced signal 150 shown in FIG. 3g is read out.

The reproduced signal 100 in FIG.
2 is not detected.

Since the read mode signal 220 is valid, the output of the comparator 13 passes through the AND circuit 16 and the OR circuit 17 and becomes the signal 230.

As shown in FIG. 3g, the slice level Vo of the comparator 13 is set to 1/2 of the reproduced signal amplitude.

Figure 3h shows the envelope signal 24 in this case.
It is 0. The envelope signal 240 is input to the serial port 19, and an interrupt signal 200 is output to the CPU 9 every time a predetermined number of pulses is detected.

As shown in FIG. 3b, when a defective mark 150a is recorded, a zag occurs due to the low frequency cut-off characteristic of the reproducing circuit 5, and the first few pulses are wider than the subsequent pulses. As a result, the "0" pulse following the first "1" pulse of the envelope signal 240 cannot be normally detected as the start pit of the serial port 19.

Therefore, an embedding pulse of a high frequency pulse having the same level as the modulation signal 130 indicated by A is implanted for a predetermined period T at the beginning of the defect mark signal 150a in FIG. 3A. In this way, zag can be suppressed by the low frequency cutoff characteristic of the reproducing circuit 5.

The defective mark signal 150 is a pulse with a width sufficiently wider than the maximum dot spacing between recording dots and is sufficiently larger than the minimum defect of the disk, so that a good envelope signal 240 can be detected except for particularly large dropouts. .

As is clear from the above description, according to the present invention,
By inspecting sectors for defects in advance and writing defective mark signals in the defective sectors, defective marks can be detected while recording data during data recording.
Furthermore, during data playback, defective sectors can be detected at the same time as data playback, and defect verification does not require a special optical head or disk rotation wait time required for playback verification processing, making it possible to achieve high-speed throughput using conventional heads. be able to.

Effects of the Invention As explained above, according to the present invention, in a one-head optical disk recording and reproducing apparatus, there is no need to wait for rotation during data recording or data reproduction on an optical disk in which a defective mark has been written in a defective sector. It is possible to perform real-time defective sector detection and speed up sector replacement processing. Furthermore, the practical effects are great, such as fewer malfunctions due to defects in the optical disk.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an optical disk recording/reproducing apparatus according to an embodiment of the present invention, Fig. 2 is an external view of the optical disc, Fig. 3 is an operating signal waveform diagram of the embodiment shown in Fig. 1, and Fig. 4 is a defect FIG. 5 is a block diagram of one embodiment of the mark generation/detection circuit, and is an explanatory diagram of the optical head portion of a conventional optical disk recording/reproducing apparatus. 1... Optical disk, 2... Motor, 3... Optical head, 4... Recording circuit, 5... Reproducing circuit, 6...
Data modulation/demodulation circuit, 7...Failure mark generation/detection circuit, 8...Defect detection circuit, 9...CPU, 10
... Sector, 11 ... Guide track, ID ... Sector identification section, 12, 13 ... Comparator, 1
4, 15... Comparison voltage source, Vf, Vo... Slice level, 16... AND circuit, 17... OR circuit, 18... Envelope detection circuit, 19... Serial port, 30... Delay circuit, 31... ...High frequency pulse generation circuit, 32... Addition circuit, 150...
...Defect mark signal, 200...Defect mark detection interrupt signal, 150a, 150b, 150c...Defect mark, A...High frequency pulse implantation part.

Claims (1)

[Scope of Claims] 1. In an optical disk recording and reproducing apparatus that records and reproduces information on an optical disk having an optically detectable guide track divided into a plurality of sectors, the light beam focuses laser light on the sector. a head; a data modulation/demodulation means for modulating and demodulating data; a defective sector detection means; generating a defective mark signal consisting of a pulse train having a pulse width sufficiently longer than the maximum signal inversion interval of the modulated output of the data modulation/demodulation means; A defective mark recording means for recording, a slice level generation means for generating two slice levels, and a reproduction signal at different slice levels generated by the slice level generation means are compared to identify defective marks during recording and reproduction of data. The apparatus includes a defect detection means for checking the presence or absence of a defective sector, and a sector replacement means for replacing a defective sector with a normal sector, and prior to using the optical disk, the defective sector detection means examines the defective sector and records the defective mark on the defective sector. The defective mark is recorded by the means, and the slice level generating means applies a slice level Vf higher than the recording signal amplitude of the reproduced signal reproduced by the optical head during data recording to the defective mark generating means to record the defective mark. The presence or absence of a defective mark signal recorded in a recording sector is inspected, and if a defective sector signal is detected from the sector, the sector is substituted for recording to a normal sector, and the reproduced signal reproduced by the optical head during data reproduction is The present invention is characterized in that a slice level Vo of approximately half of the above is applied to the defective mark generating means to check the presence or absence of a defective mark signal in the sector, and when a defective sector signal is detected, data is reproduced from an alternative sector. Optical disk recording/playback device. 2. The defective mark recording means includes: a first pulse signal generating means for generating a low frequency pulse train signal that is sufficiently longer than the maximum signal inversion interval of the modulated output signal; a delay means for delaying the defective mark; and a delay means for delaying the defective mark. a second pulse train generating a high frequency pulse train having the same frequency as the modulated output signal during a delay time period;
a pulse generating means, and an adding means for adding the output of the first pulse signal generating means and the output of the second pulse generating means, adding a high frequency pulse train to the beginning of the low frequency pulse train to mark a defective mark. 2. The optical disc recording and reproducing apparatus according to claim 1, wherein the optical disc recording and reproducing apparatus records as a signal.