JPS61170961A - Optical information recording and reproducing device - Google Patents

Abstract

PURPOSE:To record a delete code having a precise pulse width without the influence of the transient response to an optical servo system by writing plural pulse stringse superposed in their sections '0' in a sector information recording area where the string has been recorded or not yet. CONSTITUTION:In the sector to be deleted, a multiplexer 10 selects a recording signal 12 to the deleting side. A recording gate is inputted to a delete signal generating circuit 16 and a superposed pulse generating circuit 26 as well. The superposed pulse is ORed 27 so as to be superposed in the '0' section of the delete code and becomes a recording signal. The superposed pulse terminates mainly the transient response of the optical servo until the top '1' of the delete code is inputted, and used for controlling a sufficiently stable optical output in the section '1'. On the other hand, a semiconductor servo drive circuit 11 operates the optical servo system even at the time of recording, namely, modulating a pulse, and controls the optical output of the semiconductor laser at a regulated optical output.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention records information on an optical recording disk having an optically detectable guide track, the guide track being divided in advance into a plurality of sectors.

A type of light that records a pulse train of a specific pattern especially in a bad sector or an unused sector in a device that is to be played back, and upon playback, detects the pulse train of the specific pattern to determine that sector as a bad or unused sector and prevents it from being recorded or played back. The present invention relates to an information recording/reproducing device.

As a conventional optical information recording/reproducing device, for example, Japanese Patent Application No. 59-43
No. 415. Since the recording wavelength of an optical recording disk is generally about 1 μm, dropouts of reproduced signals are likely to occur due to defects on the surface of the optical recording disk. Due to the occurrence of this dropout, the raw error rate of the optical recording disk cannot be guaranteed to be 10-4 to 10-6L. Therefore, various error control techniques have been proposed to overcome this low error rate. For example, in the case of a non-rewritable optical recording disk, if data is recorded in a certain sector and then demodulated and it is determined that error correction is impossible, a pulse train of a specific pattern is recorded in the defective sector and then transferred to another sector. Record the data again. This operation in which a pulse train of a specific pattern is recorded in a defective sector and the data in that sector is not reproduced is called a delete.

Furthermore, when there is a dropout such that correct reproduction is predicted to be impossible even if data is recorded in the information recording area of an unrecorded sector, the sector is similarly determined to be a bad sector and deleted. FIG. 3 shows a configuration diagram of an optical information recording/reproducing device that performs this conventional delete operation and improves the reliability of the optical recording disk. 1 is a photodetector that detects the reflected light from the optical recording disk. It is. Reference numeral 2 denotes a focus control circuit which uses a control error signal output from the photodetector 1 to control the focusing of a minute spot light onto the surface of the optical recording disk. 3
The tracking control circuit works so that the minute spot light follows the guide track. Reproduction signal 4 from photodetector 1
is output and binarized by the waveform shaping circuit 6. This 2
The sector detection circuit 6 detects the sector address to be recorded or reproduced based on the converted signal, and the CPU 7 takes in the sector address. If the CPU 7 matches the sector address to be recorded or reproduced, the recording gate generation circuit 8 outputs a recording gate to the modulator 9, and the recording signal 12 is sent to the semiconductor laser drive circuit 11 via the multi-supplexer 10. The semiconductor laser drive circuit 11 optically modulates the semiconductor laser 13 according to the recording signal. This optically modulated light is irradiated onto an optical recording disk to record data. On the other hand, the recorded data is demodulated by the demodulation circuit 14 from the binary reproduction signal outputted from the waveform shaping circuit 6. If it is determined that error correction is not possible as a result of demodulating the recorded data, or if a dropout is determined that error correction is not possible as a result of reproducing unrecorded sectors, the dropout detection 16 detects a dropout. If so, it is determined that it is a bad sector, and the delete code generating circuit 16 generates a pulse train code of a specific pattern. Through such a delete operation, a delete code is overwritten on the bad recording sector.
! . Ya □(D
- In the case of an unrecorded sector with a dropout, only the delete code is recorded.The delete code consists of a pulse train with a specific pattern, but in order to be able to reliably distinguish it from data, the maximum code for normal data must be A pulse train that is sufficiently wider than the inversion interval is used.

FIG. 4 shows signal waveforms at various parts in FIG. 3.

FIG. 4a) shows an area in which a certain specific track of the optical recording disk is further divided, that is, a signal of a sector 19, and the designated sector is detected by the sector detection 6. 18 is an information recording area and shows how data is recorded. b) shows an example of a delete code pattern.3
A repeating pulse train of ``0'' and ``1'' is overwritten in the information recording area.

The pulse "1" is the recording power state, and the overwritten data in the information recording area is lost, and the delete code "1" indicates the recording power state.
Three pulse widths of "1" are written.

The delete detection 20 reliably detects a pulse width of "1" that is sufficiently wider than the maximum inversion interval of this data. For example, a period of pulse width "1" is counted using a reference clock signal or the like, and if the pulse width is equal to or greater than a predetermined pulse width, it is identified as one pulse of a delete code. In pattern b), three pulses of the delete code are detected and it is determined that the sector has been deleted.0 Problems to be Solved by the Invention However, in the above configuration, the first pulse of the delete code Since the pulse width tends to be recorded narrower than a predetermined pulse width, a delete detection error occurs, and furthermore, focus control and tracking control become unstable when recording a delete code. First, the reason why the leading pulse width is recorded narrow will be explained. The delete code is optically modulated by the semiconductor laser drive circuit 11 and irradiated onto the optical recording disk. However, since the semiconductor laser 13 is characterized in that its optical output-drive current characteristics fluctuate drastically due to temperature changes, it cannot be used for predetermined optical recording. Therefore, for example, a bin diode 22 is placed adjacent to the light emitting surface to apply optical power servo.

That is, when switching from the reproduction state to the recording state, the value of the comparison reference voltage of the servo system is naturally changed. At this time, a transient response occurs depending on the frequency characteristics of the servo system. Figure 4 d)
shows the optical output waveform when the optical power servo is switched as described above. Figure 4C) is the recording gate signal.
1” level indicates the recording state. 23 represents the recording power level, and 24 represents the reproduction power level. The optical power servo in the recording state starts immediately after light emission, that is, from the rising edge of the leading pulse 21, and reaches a predetermined specified power level after a certain amount of time has elapsed depending on the frequency characteristics of the servo system. The time it takes to reach this predetermined level depends on the frequency characteristics of the servo system, but is limited to approximately several μB. Therefore, since a transient state of the servo system as shown in 25 occurs in the optical output of the pulse at the beginning of the delete code, the required pulse width cannot be recorded. Figure 4 e) shows the waveform of the reproduced signal 40 from the optical recording disk recorded by the optical output signal as shown in d), and Figure 4 f) shows the waveform of such reproduced signal e. The subsequent signal waveform is shown. As described above, the pulse width of the shaped binary signal of f is counted by a reference clock or the like, and it is determined whether the pulse width is a predetermined pulse width or not. Therefore, since the pulse width at the beginning of the delete code is narrower than a predetermined width, the sector is not determined to be deleted in the delete detection 20, and a detection error occurs. Next, the reason why focus control and tracking control become unstable during delete recording will be explained. The pulse width of the delete code is set to be sufficiently wider than the maximum inversion interval of data in order to reliably distinguish it from data, and approximately 5 to 1 μ8 is considered appropriate. If the repetition frequency of the data recording signal is sufficiently high compared to the frequency characteristics of focus control and tracking control, the servo system will respond to the recording signal and the control will not become unstable. However, like the delete code, the rOJ pulse, that is, the optical output is zero □8. ~,. , 30o, yo7, -ka 3□18ka I is 9%) When the racking error signal is deleted, as shown in h, disturbance occurs on the original error signal, making focus control and tracking control unstable. I end up.

In view of the above, the present invention records a delete code with an accurate pulse width without being affected by the transient response that occurs when switching from reproduction to recording in an optical servo system, performs stable delete detection, and This is an optical recording and reproducing device that can maintain stable control while suppressing disturbances to focus control and tracking control that occur during recording.

Means for Solving the Problems The present invention provides means for recording and reproducing data in sector units on an optical recording disk having an optically detectable guide track, the guide track being divided into a plurality of sectors; Recorded or unrecorded sector information of a pulse train consisting of repetitions of rOJ and rIJ having a width wider than the maximum inversion interval of , and in which a plurality of pulse trains are superimposed in the "o" section of this pulse train. This is an optical information recording/reproducing device including means for writing into an area.

Effect of the present invention With the above-described configuration, the transient response at the time of switching from reproduction to recording of the optical servo system is detected by rOJ at the beginning of the delete code.
When recording a "1" section, that is, a delete code, it is possible to record with a sufficiently stable optical output in terms of servo. Therefore, it is possible to provide an extremely stable optical information recording/reproducing apparatus in which the pulse width of the first "1" section is recorded narrowly and delete detection errors do not occur. In addition, since the optical output level in the rOJ section does not all become zero when recording the delete code, there is less disturbance to the recording signal to the focus error signal and tracking error signal, and stable focus is maintained even when the delete code is being recorded. control and tracking control.

Embodiment FIG. 1 shows a configuration diagram of an optical information recording/reproducing apparatus in an embodiment of the present invention. Components that are the same as those of the conventional example shown in FIG. 3 are given the same numbers. Similarly to the conventional example, a reproduced signal 4 from an optical recording disk is waveform-shaped by a waveform shaping circuit 5, a sector address to be recorded or reproduced is detected by a sector detection circuit 6, and the data is taken into a CPU 7. The CPU 7 triggers the recording gate generation circuit 8 in the section of the sector position. In the sector to be deleted, the recording signal 12 is selected to the de-IJ-to side by the multi-supplexer 1o. The recording gate includes a delete code generation circuit 16 and a superimposed pulse generation circuit 26.
is also entered. The superimposed pulse is logically summed (27) and becomes a recording signal so that it is superimposed on the "0" section of the delete code. The superimposed pulse mainly ends the transient response of the optical servo by the time the first "1" of the delete code is input.
'' is used to control the light output in a sufficiently stable manner. On the other hand, the semiconductor laser drive circuit 11 operates the optical servo system even during recording, that is, during pulse modulation, and controls the optical output of the semiconductor laser to a specified optical output level. The pulse-modulated optical output signal is received by a pin diode 22 disposed close to the semiconductor laser, and the peak value of the received pulse signal is held by a peak hold circuit 28 at that level.

This held peak value is compared with a reference voltage 29 and outputted, and a servo system is configured so that a specified optical output level can be obtained even during recording. Therefore, the pulse train to be superimposed on the rOJ section of the delete code may be set to a pulse width and pulse interval sufficient for the peak hold circuit 28 to hold the peak value. According to another study, when the superimposed pulse is overwritten with the underlying data, the "o" of the data
"1" of the superimposed pulse happens to coincide with the sign part of
It is necessary to avoid a superimposed pulse pattern in which a series of "1" levels occurs, making it difficult to distinguish it from the "1" section of the original delete code. Therefore, as the optimal pattern for superimposed pulses, it is necessary to select a pattern in which the pulse width is as narrow as possible, has a value sufficient to maintain the peak value, and the pulse interval is sufficiently wide, so that consecutive "1" levels do not occur. be.
In I-optical recording discs, differential recording is used to record only the rising/falling edge information of the modulation code in order to avoid an increase in jitter due to the delicate characteristics of recording power and second-order distortion of the reproduced signal. ing. For example, the pulse width of an MFM code is T.

1.5T, 2T, differential recording is performed with these codes, and the highest recording efficiency is written on the differentially recorded data on the optical recording disk surface, for example, as shown above, and in the worst case,
If a series of "1" levels occurs, recording of superimposed pulses will not increase the sibling detection error even if there is an effect of jitter or the like. FIG. 2 is a diagram showing signal waveforms at various parts in the configuration of FIG. 1. FIG. 2a) is a format diagram showing the time relationship between the sector 19, the track address, the sector address 17 in which the sector address is coded, and the information recording area 18. b) shows a recording signal that is logically ORed with the superimposed pulse in the "0" section of the delete code.

C) is a recording gate, and when it is at the "1" level, the optical power is controlled to the recording light level. d) shows the optical output waveform of the semiconductor laser 13 modulated by the recording signal waveform b).

As shown in 3o, the transient response of the optical power servo is completed by the time the first "1" pulse of the delete code rises due to the superimposed narrow pulses, and the transient response of the optical power servo is completed from the rising edge of the first "1" pulse. It can be seen that the specified optical output level has been reached. e) is the reproduced signal after overwriting the delete signal of b) in the data section, and f) is the reproduced signal after waveform shaping 6.
Shows digitized output. As can be seen from f), in the conventional configuration, the pulse width of the leading "1" was narrow due to the transient response of the optical power servo system, whereas in this embodiment,
The pulse width of a predetermined delete code has been detected. q)
The focus error signal h) is a tracking error signal, and unlike the conventional example, the optical power does not remain at zero level for a long time, but becomes recording light intermittently at the "1" portion of the superimposed pulse. No large disturbance occurs in the tracking error signal h) or the focus error signal. Therefore, de IJ
- Stable focus control even during delete recording by ORing the superimposed pulses in the "0" section of the delet code;
Tracking control can be performed.

In this embodiment, a plurality of pulse trains are superimposed on all parts of the delete code "0", but even if a plurality of pulse trains are superimposed only on the first rOJ part, the first effect of the optical power servo system can be improved. It is quite possible for the transient response to reach the specified optical output level before the first level of "1" begins.

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, a delete code, which is an identification code of a defective sector, is controlled to a specified output light level by applying an optical power servo even during recording, using a semiconductor laser drive circuit. Even when writing is performed on an optical recording disk, recording and playback can be performed without narrowing the pulse width at the beginning of the delete code due to the transient response of the optical power servo system, making it possible to perform extremely reliable delete detection. . Further, disturbances to error signals of focus control and tracking control can be reduced during delete recording, and stable operation of the control system is possible, which has a great practical effect.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an optical information recording/reproducing apparatus according to an embodiment of the present invention, FIG. 2 is an operational waveform diagram of the same embodiment, FIG. 3 is a block diagram of a conventional optical information recording/reproducing apparatus, and FIG. 4 is an operating waveform diagram in FIG. 3. 1B...Information recording area, 19...Sector, 16...Delete code generation circuit, 26...
...Superimposed pulse generation circuit. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
Illustration □ Figure 4 dog)

Claims (1)

[Claims] means for recording and reproducing data in sector units on an optical recording disk having an optically detectable guide track, the guide track being divided into a plurality of sectors; means for writing a pulse train consisting of a repetition of "0" and "1" and in which a plurality of pulse trains are superimposed on the "0" section of this pulse train into a recorded or unrecorded sector information recording area; An optical information recording/reproducing device comprising: