JPH05135365A - Re-writable optical disk device - Google Patents

Abstract

PURPOSE:To improve the efficiency of write by correcting and controlling a head position corporating with tracking control in accordance with the detective result of the presence of an impulse received from the head when a matter that the continuity of the write is not held by a present address read is decided. CONSTITUTION:Data is written on a re-writable optical disk D having address information by an optical head device part (head) 2 and the head 2 is positioned by a tracking servo circuit 10. The present address is read from the disk D by the head 2 and whether the address holds the continuity of the write or not is decided by a microcomputer 14. Thus, when the discontinuity of the write, that is, detrack is decided, in accordance with the decision of an impulse sensor 22 deciding the presence of impulse force received by the head 2, the position of the head 2 is corrected and controlled corporating with the circuit 10 by the microcomputer 14. Thus, the appropriate write is performed while correcting the detrack and the efficiency of the write is improved.

Description

Detailed Description of the Invention

[0001]

The present invention relates to absolute time information (ATIP
= Absolute Time in Pregroo
and a writable optical disc device for writing data on a writable optical disc having address information such as ve),
In particular, it relates to a portable type optical disc device.

[0002]

2. Description of the Related Art As a writable optical disc, a CD-WO (Write Once) that can be written only once.
rewritable CD-MO (Magnetic and Opt) in which writing is performed by applying a magnetic field along with laser irradiation.
ical Compact Disk) and the like are known. Pre-grooves for guiding the information writing head are formed on these writable optical disks, and in order to write and record information accurately, it is necessary to properly follow these pre-grooves. Tracking tracking control must be performed. If the write head comes off the pre-groove for some reason (this is called detrack), the recording of that portion will be inaccurate.

Some optical disks have absolute time information in order to improve their recording density. This absolute time information has, for example, 75 frames per second and is composed of 42-bit absolute time data. This absolute time data has an NR that has a bit rate of 3150 bps (ie 42 bits x 75 frames = 3150 bps).
Z (Non Return to Zero) code, which is biphase-mark modulated with a bit clock of 6.3 kHz, and the modulated biphase mark signal is frequency-modulated.
It becomes a wobble signal of the 05 kHz PM signal. Thus, when the master disc of the optical disc is produced, a wobbling pre-groove wobbled in the direction orthogonal to the spiral recording track on the optical disc is formed based on the wobble signal, and thus the absolute time information is held.

Thus, in the case of an optical disc having absolute time information, as a measure against the writing error due to the detrack, the continuity of writing and recording is checked while constantly monitoring the absolute time information, and the detrack occurs. A detrack detecting method for stopping the writing operation is disclosed in Japanese Patent Application No. 1-332958 filed on Dec. 25, 1991 by the present applicant.

[0005]

However, the writing of the information data to the optical disc is not completed just by stopping the writing operation, and the writing process must be continued again later. Furthermore, in this post-processing as well, the processing differs depending on the cause of detrack. That is, if there is a scratch on the optical disk, it is not possible to write or record to the scratched portion, but if the write head is displaced due to impact force, return it to that position and write again. If it is done, write-once recording is possible.

Therefore, an object of the present invention is to provide a writable type optical disc apparatus which not only improves the efficiency of writing information data to an optical disc but also appropriately writes while correcting detrack as much as possible. To do.

[0007]

In view of the above object, the present invention has a writing device having a head for writing data on a writable optical disc having address information, and a tracking control means for positioning the head. The impact sensor for detecting the impact force applied to the head, the reading unit for reading the address at the current writing time from the optical disc, and the address at the current writing time for reading keep the continuity of writing. If the result of the determination is a discontinuity of writing, the determination unit determines whether or not there is an output of the impact sensor, and cooperates with the tracking control unit to determine whether the head Provided is a writable optical disk device, which is provided with position correcting means for correcting and controlling the position.

[0008]

While writing data on the optical disk, the address of the writing location is read by the reading means, and it is judged by the judging means whether or not the address has continuity. If the address is discontinuous, the writing head receives it. Position correction according to the output of the impact sensor that detects the impact force, that is, whether the cause of the discontinuity is simply the impact force from the outside or the presence of scratches or protrusions on the optical disk The head position correction control is made different by the means, and the writing operation is continued.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in more detail based on the embodiments shown in the accompanying drawings. Absolute time information is, for example, 7
The information is one fifth of one second, and this unit is called one frame. TR in FIG. 3 indicates a track along the pre-groove of the optical disc, and m, m + 1, ... Show absolute time information for each frame. A writing device capable of reading this absolute time information is configured as shown in FIG. 1, for example. The optical disc D is rotated by the spindle motor 1 at a constant linear velocity.

Reference numeral 2 indicates an optical head unit, which is a semiconductor laser 2a for outputting a laser beam which is on / off modulated by a given information data signal, and a laser beam for obtaining a reflected light for generating a servo signal. Outputting semiconductor laser 2b, collimating lens 2c, polarization beam splitter 2d, quarter wavelength plate 2e, dichroic mirror 2f that reflects only a specific wavelength beam, objective lens 2
An actuator 2h including a coil for driving g and a magnet, and a four-division photodetector 2j to which a laser beam from the beam splitter 2d is supplied via a cylindrical lens 2i.

The output signal of the four-division photodetector 2j is A,
Assuming B, C, and D, the adder circuit 3 causes A + B + C + D.
Output signal is formed, and the subtraction circuit 4 outputs (A + D)-
A focus error signal represented by (B + C) is supplied to the focus servo circuit 5, and a control signal for focus control is supplied to the actuator 2h.

The output of the adder circuit 3 is the bandpass filter 6
Is supplied to. Bandpass filter 6 is 22.05 kHz
An output signal of the bandpass filter 6 having a pass band of z ± 900 Hz and corresponding to the pregroove is supplied to the synchronous detection circuit 7 and the waveform shaping circuit 11.

The synchronous detection circuit 7 has terminals 2 to 22.0.
A 5 kHz sinusoidal signal is provided. A tracking error signal is extracted from the output of the synchronous detection circuit 7 by the low-pass filter 9, and the extracted tracking error signal is supplied to the tracking servo circuit 10, and the tracking servo circuit 10 sends the optical head device unit 2 to the actuator 18. A control signal for tracking control for driving is given.

The waveform shaping circuit 11 obtains a pulse train modulated by the absolute time code of the optical disc format. This pulse train is demodulated in the demodulation circuit 12 into data bits of the absolute time code, and the demodulated absolute time information controls the system.
4 will be supplied.

On the other hand, the optical head device unit 2 has an impact sensor 22 for detecting an impact force received from the outside.
Is attached, and the output of this sensor is input to the microcomputer 14. Furthermore, the demodulation circuit 12
There is provided an error counter 20 for counting the number of detracks being written from the absolute time information demodulated in the above.
Has been entered in.

Further, the microcomputer 14 uses the absolute time information transmitted from the demodulation circuit 12, the output from the impact sensor 22, and the cumulative detrack number from the error counter 20 to perform the optical head device section by the process described in detail below. The position 2 is corrected and controlled. Further, the microcomputer 14 transmits the detrack generation address and the like to the detrack recording device 16 to record the recording state of the optical disc D.

The flow of processing by the microcomputer 14 will be described below with reference to FIG. In step 30, an initial value of the timer time variable t, which is a time signal as a reference, is set. In step 31, the timer function of the microcomputer causes one frame (1 frame) which is the minimum unit of the absolute time information of the optical disc D to be written.
/ 75 seconds), the timer time variable t is incremented by 1 in step 32 for each frame, and the absolute time information T is read in step 33. Unless the detrack occurs, the read absolute time information T should match the timer time t at the time of reading, and this determination is made in step 34.

If they match, the process proceeds to step 39,
If it is determined that the writing has not been completed, the step 3 is performed again.
Go to 1 and repeat the above steps. If they do not match, in step 35, it is determined whether or not there is an output from the impact sensor 22. The presence of this output indicates that the optical head device unit 2 was originally moved from the original position to the position of the absolute time information read in step 33 due to the impact force. In order to return to the position of 1, the tracking servo circuit 10 shown in FIG. Then, in step 37, the read absolute time information T and the timer time variable t at the time of the previous reading are stored. This step 37
The significance of the process will be described later with reference to FIG.

Then, in step 38, the timer time variable t is reset to the absolute time information value T read at the present time. In step 39, it is determined whether or not the writing work has been completed. If not completed, the above steps are repeated. If completed, in step 40, the absolute time information T and timer time t stored.
Although each set information may be displayed on a display or the like, it may be recorded on the optical disc D itself and used during reproduction.

If there is no output from the impact sensor in step 35, detrack occurs even though the optical head device 2 does not receive an impact force, and the optical disc is free from scratches and protrusions. It can be seen that there is. In this case, the processing is divided into two types based on the history of the cumulative number of detracks output from the error counter 20 shown in FIG.

That is, in the case of a scratch, generally, the cumulative number of detracks does not suddenly increase, and the rate of increase thereof gradually increases. It is determined that there is a scratch on the optical head device unit 2 and the address of the optical head device unit 2 is greatly advanced with respect to the optical head D in step 43 in order to avoid the scratch.

On the other hand, in the normal case where the cumulative number of detracks does not increase significantly, it is not a case of scratches. The head device unit 2 advances the address with respect to the optical head D. Step 42
Alternatively, after the processing of 43, the process proceeds to step 37 as in the case of step 36.

The state of writing and recording when detrack occurs and the significance of steps 37 and 38 in FIG. 2 will be described with reference to FIG. First, in the writing / recording state M1, writing was normally performed up to the absolute time (m + 4) frame position of the track TR along the pre-groove, but the next absolute time (m + 5) frame was generated due to external impact force or the like. A case is shown in which the position cannot be moved to the position, the position moves back to the absolute time (m + 3) frame position, and writing is further performed from that position. In the case of the write recording state M2, the writing was normally performed up to the absolute time (m + 4) frame position. However, due to an external impact force or the like, the writing jumps to the absolute time (m + 6) frame position and the writing starts from that position. Shows when done.

In the writing / recording state M1, the absolute time T read during writing at the position of the absolute time (m + 3) frame that has returned to the reverse is (m + 3) frames, but the timer time t is ( m + 5) frames. Therefore, in step 23 of FIG. 2, the two do not match,
Go to steps 24 and 25. In step 25, the absolute time (m + 3) and the previous timer time (m + 4) are stored.

After the writing on the optical disk D is completed, (T, t) = ((m + 3), (m +
From 4)), first, it is understood that this detrack is a retreated detrack because T <t. Therefore, although the writing was normally performed up to the position of the absolute time (m + 4) frame, it can be recognized that the writing was performed back to the position of the absolute time (m + 3) frame and the continuation was started from there. That is, the writing / recording state M1 of FIG. 3 can be reproduced.

Next, in the writing / recording state M2, the absolute time T read during writing at the absolute time (m + 6) frame position jumped forward is (m + 6) frames, but the timer time is t is a (m + 5) frame. Therefore, in step 23 of FIG. 2, the two do not match, and the process proceeds to steps 24 and 25. In step 25, the absolute time (m + 6) and the previous timer time (m + 4)
And remember.

After the writing on the optical disk D is completed, (T, t) = ((m + 6), (m +
From 4)), it is understood that this detrack is a detrack that flew forward because T> t. Therefore, although the writing was normally performed up to the position of the absolute time (m + 4) frame, it can be recognized that the writing jumped to the position of the absolute time (m + 6) frame and the continuation thereof was started from there. That is, the write / record state M2 of FIG. 3 can be reproduced.

[0028]

As is apparent from the above description, according to the present invention, even if there is a writing error, writing is not stopped at that point, so that the efficiency of writing information data to the optical disk can be improved. Further, in the writing process, the causes of the detrack are classified, and the head position correction processing is performed according to each cause, so that the writing on the optical disk can be optimized.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a writable optical disk device according to the present invention.

FIG. 2 is a process flow diagram of a writable optical disc device according to the present invention.

FIG. 3 is an explanatory diagram of a writing / recording state on an optical disc.

[Explanation of symbols]

 14 Microcomputer 20 Error Counter 22 Impact Sensor D Optical Disk M1 Writing / Recording State M2 Writing / Recording State TR Track along Pregroove

Claims (1)

[Claims] 1. A writing device having a head for writing data on a writable optical disc having address information, and a tracking control means for positioning the head, wherein the impact force received by the head is detected. An impact sensor, a reading means for reading the address at the time of the current writing from the optical disc, a judgment means for judging whether or not the read address at the time of the current writing holds the continuity of the writing, When the result is the discontinuity of writing, a position correcting unit that controls the position of the head in cooperation with the tracking control unit according to the presence or absence of the output of the impact sensor is provided. Characteristic writable optical disk device.