JPS61170928A - Optical disk device - Google Patents

Abstract

PURPOSE:To detect a signal securely by writing a deleting pulse train signal with light power larger than light power with which data are written. CONSTITUTION:When the deleting pulse train signal is recorded on an optical disk 5, track address information 18 to be recorded and a deletion enabling signal 20 which reports the execution of deleting operation are applied to a recording optical power control circuit 15 and a control circuit 15 controls a laser driving circuit 10 so that a data modulated signal is outputted from an optical head 7 with the light power larger than the light in its recording by a constant rate. When the optical head 7 reproduces a deleted track, a deletion detecting circuit 17 detects a deleting pulse train signal different in signal pattern from the data modulated signal from the reproducing signal from a head amplifier 11. Consequently, the deleting pulse train signal of good quality is reproduced and its pattern is detected.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an optical information recording/reproducing apparatus for recording and reproducing information on an optical recording disk having an optically detectable guide track.

Conventional Technology For optical recording disk memories, which are considered promising as high-density, large-capacity memories, error control technology is very important in order to overcome the low error rate of optical recording disks.

Optical recording disks usually have optically detectable guide tracks such as guide grooves in order to achieve high track density, and the recording layer formed on these guide tracks has a thickness of 1μ.
Irradiate a laser beam focused to about m to drill holes or
A change in reflectance is caused and recorded.

Since the recording dot and track pitches are approximately 1 μm, various processes such as formation of optical recording disk manufacturing tracks, manufacturing of replica disks, deposition of recording materials, formation of protective layers, and usage environment of unrecorded disks are required. 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 10-4 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.

For this reason, optical information recording and reproducing devices using optical recording disks usually have strong error control. Figure 7 is a diagram showing details of the format of signals actually recorded on optical recording disks. be. 1 is a synchronization signal to encourage clock synchronization during data reproduction, 2 is a data mark using a certain code to indicate the start of data, and 3 is a data mark with redundant bits added based on error correction code theory. , is interleaved encoded data. The recording signal block B consisting of the synchronization signal 1, data mark 2, and encoded data 3 is recorded in the information recording area of the sector divided by the address section 4, as shown in B of FIG. The address section 4 generally records track addresses and sector addresses.

In this way, using an optical recording disk as a sector structure and recording data by dividing it into certain units is very effective when recording digital information where the data length is variable, and it makes the recording area more efficient. Can be used often.

Dropouts that exist in optical recording disks generally reduce the envelope of recorded and reproduced signals and cause demodulation errors, and if these dropouts occur beyond the ability of the error correction code, the errors cannot be corrected during demodulation.

In the case of a non-rewritable disc, if data is recorded in a certain sector and then read out and it is determined that the demodulation error is uncorrectable, the data in that sector is processed so that it cannot be played back, and the data is transferred to another sector. We need to record some more data.

Also, when updating a part of data or deleting a file, it is better to prevent data in sectors that are no longer used from being played back.

Furthermore, if there is a dropout in the information recording area of an unrecorded sickle sector that would prevent correct playback even if data is recorded, that sector will be treated as a bad sector and no data will be recorded. - It is desirable to perform such processing, and in this case, the same applies to rewritable optical recording discs.

As shown in the above example, if the sector in which data is to be recorded or reproduced is a bad sector, or if it is no longer used for purposes such as updating, it is necessary to take steps to identify this at the time of reproduction. is necessary.

Therefore, in order to identify bad sectors and unused sectors, multiple pulse trains of a specific pattern (
Hereinafter, the operation of writing a plurality of pulse trains will be referred to as a delete, and the plurality of pulse trains will be referred to as a delete pulse train. ) is written over the recorded data (Patent Application 1987-2).
No. 22405, Japanese Patent Application No. 59-43415). This method will be briefly explained.

Data section of bad or unnecessary sectors (shown in Figure 9a)
A delete pulse (shown in FIG. 9) having a frequency considerably lower than the data frequency is overwritten on the data. For data recorded overlappingly with a constant optical power, the recorded bits of the data are destroyed by the recorded bits of the delete pulse, and the recorded data cannot be reproduced.

The reproduced signal at this time is shown in FIG. 9C. A delete pulse train, which is a specific pattern that is distinguished from a data signal, is detected in the signal reproduced at this time, and is recognized as a bad sector (or unnecessary sector).

Next, when recording data by rotating an optical disk at a constant rotational speed, as you can easily understand, the rotation speed of tracks away from the center becomes faster, so data is written to the optical disk with a constant optical power. In this case, the power density becomes smaller in tracks closer to the outer periphery, making it impossible to write uniformly over the entire disc. It has long been well known that as a way to solve this problem, by reading the track address from the optical disc and writing data with an optical power (increasing the outer edge power) according to the track address, consistently good writing can be achieved over the entire disc. (Japanese Unexamined Patent Publication No. 49-38529) 0 Problems to be Solved by the Invention In such conventional optical disk devices, the optical power for writing the delete pulse train signal is the same as the optical power for writing the data. I was recording it.

In such a conventional method, the effect of suppressing data signal components due to overwriting of the delete pulse train signal is small. 10th
The figure shows the reproduced signal waveform at that time.

FIG. 10a shows the reproduced waveform when no deletion is performed. FIG. 10 shows a delete pulse train signal written to the disk. FIG. 10C shows a reproduced signal when the delete pulse train signal shown in FIG. 10S is written with the same optical power as that used to write the data signal shown in FIG. 10A.

In other words, even if you try to use the same optical power for data recording as the optical power for deleting, the emission power of the semiconductor laser will decrease when the ambient conditions, especially the temperature, increases, or the optical power of the optical disc during overwriting will decrease. As the sensitivity of the pulse train signal decreases, there are cases in which the data signal, which is suppressed by deletion, cannot be suppressed sufficiently, resulting in insufficient reliability in detecting the deleted pulse train signal.

SUMMARY OF THE INVENTION An object of the present invention is to solve such problems and provide an optical disc device that can reliably detect a delete pulse train signal.

Means for Solving the Problems In order to solve the above problems, the present invention writes a delete pulse train signal with an optical power greater than the optical power used to write data.

Function The present invention achieves the following functions and effects with the above-mentioned configuration.

That is, a light beam modulated by data is formed as data pits on the optical disk. The reflectance of these pits is about 10% higher than that of the unrecorded area (where the light beam is not irradiated). This change in reflectance is proportional to the recording light power.

Next, pits are formed by deleting on top of the data recording pits using an optical power modulated by the delete pulse train signal that is at least higher than the optical power with which the data was previously recorded. Since pits caused by deletion are written with at least higher optical power than pits caused by data, the amount of reflected light from pits caused by deletion is greater than pits caused by data. The influence of pits is greatly suppressed, and a reliable delete signal can be detected.

Embodiment FIG. 1 is a block diagram showing a first embodiment for recording a delete pulse train signal of the present invention.

In FIG. 1, 6 is an optical disk, and 6 is a disk motor that rotates the optical disk 6 at a constant speed. 7 is an optical head for writing and reading data information. 8 is a linear motor that allows the optical head 7 to access a designated track. 9 is a disk motor drive circuit that drives the disk motor 6. 1Q is a laser drive circuit that drives a semiconductor laser that is the light source of the optical head 7, and 11 is a head amplifier that amplifies the signal extracted by the optical head 7. 12 is a focus/tracking circuit that controls focusing and tracking of the optical head 7. Reference numeral 13 denotes an address reading circuit for reading track addresses previously formed on the optical disc 1 from the reproduction signal obtained by the head amplifier 11. 14 is head amplifier 11
This is a demodulation circuit that demodulates the signal extracted by.

Reference numeral 16 controls the amount of optical power with which the laser drive circuit 10 records write data or delete pulse train signals on the optical disc 5, according to the track address information obtained from the address reading circuit 13 and a delete enable signal that indicates whether or not a delete operation is being performed. This is a recording light power control circuit. 16 is a linear motor drive circuit for driving the linear motor 8. 17 is a delete detection circuit that detects the pattern of the delete pulse train signal from the reproduced signal from the head amplifier 11; Reference numeral 18 denotes a controller circuit composed of a CPU that controls the above-mentioned components.

The operation of the optical disc device of this embodiment configured as described above will be briefly described below.

First, the optical disc 6 is rotated at a constant speed by the disc motor 6. Next, the optical head 7 is subjected to focus control and tracking control by the focus/tracking circuit 12 to follow the track of the optical disk 5. Further, the optical head 7 accesses a predetermined track by a linear motor 8 activated by a linear motor drive circuit 16. The controller circuit 18 reads the current track address that the optical head 7 is currently following with the address reading circuit 13, sets the difference from the target track address in the linear motor drive circuit 16, and moves the linear motor 8 to the target track address. Search for tracks. The controller circuit 18 also performs focus pull-in sequence control, tracking sequence control, and disk motor control. Next, the operation of writing a data modulation signal and a delete signal to the optical disk 6, which is the key point of the present invention, will be explained. Laser drive circuit 10
When reproducing, a certain reproduction optical power (approximately 1 mw on the optical disc) is output from the optical head, and during recording, the recording optical power modulated into the signal (data or delete signal) to be recorded on the optical disc 5 (approximately 1 mw on the optical disc) is output from the optical head. Approximately 5
mw to 8 mw) is output from the optical head. First, the optical power when recording a data modulation signal on the optical disk 6 is determined by the controller 18 reading the track address previously formed on the optical disk 5 via the address reading circuit 13, and the track address information 1 of the track to be recorded.
9 is applied by the controller 18 to the recording light power control circuit 16, and the light power becomes the light power corresponding to the track address to be recorded (outer periphery root power is large).

The relationship between this track address and the optical power when recording the data modulation signal is shown in FIG. 2A. FIG. 2 shows an example of an optical disc in which the track address becomes larger toward the inner circumference. Next, when recording a delete pulse train signal on the optical disk 6, the track address information 19 to be recorded and the delete enable signal 2o from the terminal 2o informing that a delete operation is to be executed are applied to the recording light power control circuit 16, From Figure 2 A, the optical power when recording a data modulation signal is increased at a certain rate.
The recording light power control circuit 1 controls the recording light power control circuit 1 so that the optical head 7 outputs the light at J high (0.5 mw) light power (shown in FIG. 2B).
6 controls the laser drive circuit 1o. When the optical head 7 reproduces the deleted track, the delete detection circuit detects a delete pulse train signal having a signal pattern different from the data modulation signal shown in FIGS. 9 and 10 from the reproduced signal from the head amplifier 11. 17 detects, and when it detects a sector of the track that has been deleted at the terminal 21, it outputs a detection signal to inform the outside.

Further, the data modulation signal that has not been deleted is demodulated by the data demodulation circuit 14 and becomes read data. In this embodiment, since the optical power for deletion is controlled in the radial direction, the thermal influence on adjacent tracks can always be kept to a minimum. FIG. 3 shows a second embodiment of the present invention. This is an example. Tri-state buffer logic IC21 as recording light power control circuit
, pull-up resistor group 22. A circuit consisting of a D/A converter 23 is used. As a laser drive circuit, a reproduction power current source 24 that determines reproduction power. Turns on during playback 5
W25. Recording power current source 26 that determines recording power. It consists of 5W27 which is 0N10FF by a data modulation signal or a delete pulse train signal at the time of recording. The operation of this embodiment configured as above will be explained.

During reproduction, only S W 2 s is turned on, a current from a reproduction power current source flows through the semiconductor laser 28 (hereinafter referred to as half half), and a constant reproduction power is obtained from half half 28 .

Next, when recording a data modulation signal, the delete enable signal (DEN) at terminal 29 is inactive and “L”.
”, so 3 from MSB indicating track address information
Bit data ADa, ADb.

ADa is applied to the D/A converter 23, and a voltage proportional to the track address information controls the recording power current source. That is, when recording a data modulation signal, a current from the recording current source flows so that the inner culm power becomes smaller according to the address information of the track to be recorded.
The recording power according to the recording track address information shown in FIG. 4A is obtained from the half 28. When recording the delete pulse train, DEN of the terminal 29 becomes active and becomes H. Then, the tryst buffer IC21 becomes non-active and the output side of pIc21 is pulled up by the resistor group 22, so the track address information ADa,
Regardless of ADb and ADc, the output of IC21 is abtt
Both +t1'' and 3 bits of "Itllll" data are added to the D/A converter 23. At this time, as is clear, the maximum voltage will be output from the D/A converter 23, and the recording power current source 26, which controls the current flowing to the half 28 at this time, will also flow the maximum current. .

In other words, when recording a delete pulse train signal, regardless of the track address to be recorded, as shown in FIG. 4B, the data modulation signal is recorded with a constant optical power that is greater than the optical power of any track address that is recorded, regardless of the track address. I will do it.

Also, when performing a recording operation, 5W25 is turned OFF, and 5W25 is turned OFF.
W27 becomes 0N10FF in response to the data modulation signal or the delete pulse train signal, and the optical power modulated by these signals is output from the half 28.

FIG. 6 shows a third embodiment of the present invention.

D/A converter 30, D as a recording light power control circuit
data recording power current source 31 ./A converter 30 . A circuit consisting of a write power current source 32 at the time of deletion and a 5W 33 which is turned ON at the time of deletion is used. As a laser drive circuit, a reproduction power current source 34 that determines the reproduction power. 5W3 that turns on during playback
s, consists of 5W36 which performs 0N10FF with the signal to be recorded.

The operation of this embodiment configured as above will be explained. At the time of reproduction, only 5Was is turned on, and a current from the reproduction power current source flows in half 37, so that a constant reproduction power is obtained. Next, when recording a data modulation signal, the 3-bit data ADa, ADb, ADc from the MSB indicating track address information is converted to D/A...
A voltage proportional to the track address information added to the track address information controls the data recording power current source, resulting in the recording power shown in FIG. 6A in accordance with the track address information to be recorded. At the time of deletion, similarly to when recording data, the delete enable signal (DEN) at the terminal 38 is activated by the current generated by the data recording power current source controlled by the D/A converter 30 according to the track address information to be recorded. As a result, the 5W 33 is turned ON, and a certain current from the write power current source 32 is applied at the time of deletion to drive the half 37. At the time of deletion, the recording power becomes as shown in FIG. 6B.

Effects of the Invention As described above, according to the present invention, a delete pulse train signal can be superimposed on the data recorded area with a recording optical power greater than the recording optical power when recording the data modulation signal using a simple circuit configuration. The components of the data modulation signal that can be recorded and before being overwritten by the demarking operation are more completely suppressed by the present invention. As a result, when a sector of a deleted track is reproduced, a high-quality delete pulse train signal is reproduced, and its pattern can be detected. Therefore, the reliability of the optical disk device is further improved, and the practical effect is great.

The above has described overwriting a demark pulse train on a sector in which data has been recorded, but it goes without saying that there is no problem even if the deletion process of the present invention is applied to sectors in which no data has been recorded.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an optical disk device according to a first embodiment of the present invention, FIG. 2 is a diagram explaining the operation of the first embodiment, and FIG. 3 is a diagram of a laser drive according to a second embodiment of the present invention. A diagram showing a circuit and a circuit for controlling recording power, FIG. 4 is a diagram for explaining the operation of the second embodiment, and FIG. 6 shows a laser drive circuit and a circuit for controlling recording power in the third embodiment. Figure, 6th
The figures are diagrams explaining the operation of the third embodiment, Figure 7 is a diagram showing the format of a signal recorded on an optical disc, Figure 8 is a time chart showing the arrangement of the address part and data part of sectors, and Figure 9 1 and 10 are signal waveform diagrams showing the relationship between the data modulation signal, the delete pulse train signal, and the deleted reproduced signal. DESCRIPTION OF SYMBOLS 10... Laser drive circuit, 13... Address reading circuit, 16... Recording optical power control circuit, 18... Controller circuit, 21...・
・・Tristed Pyphalogic IC, 22...
... Pull-up resistor group, 23 ... D/A converter, 26 ... Recording power current source, 28 ...
...Semiconductor laser, 3o...D/A converter, 31...Data recording power current source, 32
... Recording power current source at de-IJ, 33...
...Switch, 37...Semiconductor laser. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
Figure Y Rack 7) Outer cylinder ---- Force circumference Figure 3 Figure 4 Figure 5 EN Figure 6 No. 1% Rebellion ν3 Kite ■
1 question Figure 7 Figure 8-111 Sector 111

Claims (1)

[Claims] a first means for recording information on a predetermined track of an optical disk by modulating optical power; a second means for recording special information having a lower frequency component than the information on the same predetermined track; an optical disc device comprising: means for making the recording light power during recording larger than the recording light power of the first means.