JPH0583970B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is directed to an optical disc which allows a user to optically record a signal with a light beam modulated based on the signal. The present invention relates to an optical disk recording device that records signals using

BACKGROUND ART AND THEIR PROBLEMS Optical discs, such as so-called DRAW discs, have been proposed that allow users to optically record signals. In such a disk, a guide groove defining a spiral track is generally provided in advance on the recording surface.
Signal recording is performed along this track.

In an optical disc player that handles such an optical disc, there is a recording operation in which a light beam is used to record a signal on a spiral track defined by the above-mentioned guide groove on the disc, and Once the above signal has been recorded, a reproduction operation is performed in which the signal is reproduced using a light beam from a spiral track, which in either case is placed opposite the rotating disk and moves in its radial direction. A light beam is directed onto the disk by an optical head. Then, during each recording operation and reproduction operation, the position of the spot on the disk relative to the track by the light beam from the optical head moving in the radial direction of the disk is detected, and the optical head is moved based on the detection signal. Tracking control is required to move the light beam from the disk across the tracks of the disk so that the light beam scans correctly over the tracks.

Tracking control in such an optical disk player usually involves a light beam being made incident on the disk by an optical head, reflected by the disk, returned to the optical head, and guided to a photosensitive section disposed therein. A tracking error detection signal corresponding to the positional deviation of the spot caused by the light beam with respect to the track on the disk is obtained from the output signal obtained by the photosensitive section when the optical head is moved. This can be accomplished by providing a servo control circuit that drives and controls the position of lenses, mirrors, etc., or the entire optical head.

The above-described tracking control allows the optical disc player to properly perform recording and reproducing operations on a disc on which signals can be optically recorded, by following the track. If an external shock is applied to the optical disc player while it is in recording or reproducing operation, or if the disc being used for signal recording or signal reproduction by the optical disc player has a defect such as a scratch. When the light beam incident on the disk scans such a defective part, the tracking state is disturbed and the position on the disk of the light beam incident on the disk rapidly moves in the direction across the track. A situation may arise in which the disk is moved to an undesired position on the disk. When the optical disc player is in a recording operation state, the position of the light beam incident on the disc moves rapidly, so that the position of the light beam on the disc has already been recorded as a signal. At the same time, the signal is returned to the part where the signal was recorded, and the signal recording state is again assumed for the part where the signal has already been recorded.
Therefore, there is a risk that not only the signal recording will be interrupted, but also the recorded contents of the part where the signal has already been recorded will be damaged.

OBJECT OF THE INVENTION In view of the above, the present invention provides that, in a recording operation state in which a disk capable of optically recording signals is mounted, a light beam incident on the disk reaches a position on the disk in a direction that crosses a track. To provide an optical disk recording device in which even if an undesirable situation occurs in which the disk is rapidly moved, there is no risk of damaging the recorded contents in a part of the disk where signals have already been recorded. The purpose is to

Summary of the Invention An optical disk recording device according to the present invention obtains a signal corresponding to a tracking error of a light beam incident on a disk on which a spiral track is formed and optical signal recording can be performed. In addition to a signal forming section and a light beam drive section that moves the light beam incident on the disk in a direction across a spiral track, the light beam drive section moves the light beam incident on the disk in a spiral shape. When the device is moved in a direction across the track, a signal corresponding to the tracking error obtained from the signal forming section is supplied, and the upper peak level and lower peak level of the signal corresponding to the tracking error are detected. A peak level detection section, a first reference level slightly lower than the upper peak level detected by the peak level detection section, and a second reference level slightly higher than the lower peak level detected by the peak level detection section. During the recording operation in which the signal is recorded on the disk, the level of the signal corresponding to the tracking error obtained from the signal forming section is set to the first reference level held by the level holding section and the second reference level held by the level holding section. a level comparison section that generates a detection output when the level range between the standard level of It is equipped with and configured.

By doing this, during the recording operation, the occurrence of a situation where the arrival position of the light beam incident on the disk on the disk rapidly moves in the direction across the track is detected immediately before the occurrence of the situation, and the signal recording is immediately stopped. Therefore, even if the light beam incident on the disk rapidly moves to an area on the disk where a signal has already been recorded, the recorded contents of that area will not be damaged. Moreover, in order to detect a situation in which the arrival position of the light beam incident on the disk rapidly moves across the track, the level of the signal corresponding to the tracking error obtained from the signal forming section is determined by the level holding section. This is done in response to the detection output from the level comparator obtained when the level range between the first reference level and the second reference level held by the Both of the two reference levels are set in advance based on the level of a signal corresponding to the tracking error obtained when the light beam incident on the disk moves in a direction across the spiral track.
Since it is determined according to each disk, it is possible to avoid erroneous detection caused by uneven characteristics between disks.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows an example of an optical disc recording device according to the present invention. A disk 1 is mounted here, on which signals can be recorded optically, and this disk 1 has a spiral track.
Opposite the disk 1, an optical head 2 is arranged so that the disk 1 can move in the radial direction,
The optical head 2 has a built-in light source 3, for example a laser light source. The optical head 2 is
A light beam is made incident on the disk 1 from the light source 3,
Further, the light beam reflected by the disk 1 is received by a built-in photosensitive section, and an electric signal corresponding to the amount of light is generated. The output signal from the photosensitive section of the optical head 2 is supplied to the signal forming circuit 4.
From this, a signal corresponding to the tracking error of the light beam incident on the disk 1, that is, a tracking error signal TE and a reproduction output RF of the signal recorded in the tracking of the disk 1 are obtained.

The tracking error signal TE is transmitted through the phase compensation circuit 5, the selection contact 6a of the switch 6, and the movable contact 6.
The signal is supplied to the drive amplifier circuit 7 via c. Then, the drive amplifier circuit 7 receives a tracking error signal.
A drive signal based on TE is supplied to the tracking adjustment drive coil 8. Thereby, the tracking adjustment drive coil 8 is connected to an optical means built in the optical head 2, for example, an objective lens or
The entire optical head 2 is driven such that the position of the spot on the disk 1 caused by the light beam incident on the disk 1 moves in the direction across the track,
In this way, the tracking adjustment is performed so that the light beam incident on the disk 1 always follows the track.
A servo control mechanism is formed.

The light source 3 built into the optical head 2 is connected to the output end of an operation mode control circuit 9, and the output of the operation mode control circuit 9 determines the recording operation state and the state in which signals are recorded on the disk 1. The light source 3 is controlled in accordance with the reproduction operation state in which the signal from the disk 1 is reproduced.

When the recording operation state is taken, first, a traverse signal St as shown in FIG. 2A is supplied from the terminal 10 to the control end of the switch 6, and the movable contact 6c of the switch 6 is connected to the grounded selection contact 6b. I am forced to do it. As a result, the tracking error signal TE is not supplied to the drive amplifier circuit 7.
The tracking servo control mechanism is disabled and the light beam incident on the disk 1 is caused to move the spot on the disk 1 across the track. At this time, the tracking error signal TE obtained from the signal forming circuit 4 has a sin waveform having a peak every time a spot on the disk 1 passes a track due to the light beam incident on the disk 1.

Further, the traverse signal St from the terminal 10 is transmitted to the switch 11 connected to the output terminal of the signal forming circuit 4.
and 12, the switch 11 is turned on during the traverse signal St, and the switch 12 is turned off during the traverse signal St. As a result, switch 1
As shown in FIG. 2B, the tracking error signal TE having a sinusoidal waveform obtained from the signal forming circuit 4 is obtained at the output end of the signal forming circuit 1 for the period of the traverse signal St, and The signals are supplied to the side peak level detection circuit 14, respectively.

The upper peak level detection circuit 13 outputs an output signal having a level corresponding to the upper peak level of the tracking error signal TE having a sin waveform.
Vt is obtained and supplied to the level holding circuit 15. The level holding circuit 15 holds the level V1, which is slightly lower than the level of the output signal Vt of the upper peak level detection circuit 13, as shown in FIG. 2B. On the other hand, a tracking error signal having a sin waveform is output from the lower peak level detection circuit 14.
An output signal Vb having a level corresponding to the lower peak level of TE is obtained, and this is supplied to the level holding circuit 16. The level holding circuit 16 holds the level V2, which is slightly higher than the level of the output signal Vb of the lower peak level detection circuit 14, as shown in FIG. 2B.

The levels V1 and V2 held in these level holding circuits 15 and 16 are determined according to the level of the tracking error signal TE having a sinusoidal waveform obtained from the signal forming circuit 4.
Since the tracking error signal TE having a sin waveform has a level corresponding to disk 1, the level V
1 and V2 also correspond to disk 1.

After the period of the traverse signal St has elapsed, the recording operation command signal Sr is supplied from the terminal 17 to the first control end of the operation mode control circuit 9, and the recording operation state is assumed. In the recording operation state, the recording signal SS is supplied from the terminal 18 to the operation mode control circuit 9, and the operation mode control circuit 9 uses its output to control the light source 3 built in the optical head 2 so that the light beam obtained from it is used for recording. It is controlled so that it is modulated by the signal SS. Therefore, a light beam modulated by the recording signal SS is made incident on the disk 1 from the optical head 2, and the recording signal SS is recorded on the track on the disk 1. At this time, the traverse signal St is no longer supplied to the control end of the switch 6, and the switch 6 is in a state where the movable contact 6c is connected to the selection contact 6a. signal forming circuit 4
A tracking error signal TE is supplied to the drive amplifier circuit 7. This allows the tracking servo control mechanism to function.

In addition, in this state, the traverse signal St is not supplied to the control terminals of the switches 11 and 12, and the switch 11 is turned off.
Further, the switch 12 is turned on, the tracking error signal TE is not supplied to the upper peak level detection circuit 13 and the lower peak level detection circuit 14, and the tracking error signal TE is transmitted via the switch 12. The signal is supplied to the positive input terminal of the level comparison circuit 19 and the negative input terminal of the level comparison circuit 20, respectively. At the negative input terminal of the level comparison circuit 19 and the positive input terminal of the level comparison circuit 20, respectively,
A level V1 from a level holding circuit 15 and a level V2 from a level holding circuit 16 are supplied.

In such a state, if the tracking servo control mechanism is performing normal tracking adjustment for the light beam from the optical head 2 that is incident on the disk 1, the tracking error signal TE is output from the level holding circuit 15. level V1 from the level holding circuit 16 and higher than the level V2 from the level holding circuit 16. Therefore, no output is obtained from the level comparison circuits 19 and 20, and a normal tracking adjustment state is maintained.

During such a recording operation state, for example, an external impact is applied such that the light beam from the optical head 2 that is incident on the disk 1 causes the spot on the disk 1 to rapidly move in the direction across the track. If such a situation occurs, the tracking error signal TE' having a sinusoidal waveform as shown in FIG. It is supplied to the positive input terminal of the circuit 19 and the negative input terminal of the level comparison circuit 20. The upper peak level of this tracking error signal TE' exceeds the level V1 from the level holding circuit 15, and the lower peak level is lower than the level V2 from the level holding circuit 16. Therefore, an output signal is obtained from the level comparison circuit 19 when the level of the tracking error signal TE' becomes higher than the level V1, and an output signal is obtained from the level comparison circuit 20 when the level of the tracking error signal TE' becomes higher than the level V1. When it becomes lower than V2, an output signal is obtained, and both outputs are supplied to an OR gate circuit 21, at the output of which a signal Sp as shown in FIG. 2C is obtained. In such a case, levels V1 and V
2 is set in accordance with the disk 1 as described above, so there is no possibility of malfunction occurring due to uneven characteristics between the disks when the signal Sp is obtained.

The signal Sp from the OR gate circuit 21 is a set-reset-flip-flop (R-S
FF) is supplied to the set terminal S of 22, and R-S
Time t1 when FF22 first rises (Fig. 2 C)
to the set state. This allows R-S FF
At the output terminal Q of 22, as shown in FIG. 2D, an output signal So rising from a low level l to a high level h at time t1 and maintaining the high level h is obtained.
This output signal So is the second output signal of the operation mode control circuit 9.
is supplied to the control end of. Operation mode control circuit 9
When the output signal So from the output terminal Q of the R-S FF 22 assumes a high level h, the recording operation state is interrupted and the reproduction operation state is assumed. As a result, a recording signal is generated for the light beam from the light source 3 built into the optical head 2.
The modulation by SS is stopped, and the light beam from the light source 3 has a light intensity suitable for reading the signal from the disk 1, and this state is a state in which the output signal Sp from the OR gate circuit 21 cannot be obtained. Even so, the reproducing operation for the disk 1 continues under proper tracking adjustment of the light beam from the optical head 2 incident on the disk 1 by the tracking servo control mechanism.

As a result, even if the spot on the disk 1 caused by the light beam from the optical head 2 incident on the disk 1 is moved to an area where a signal has already been recorded when an external impact is applied, Therefore, the recorded contents in the portion where the signal has already been recorded will not be damaged by the light beam from the optical head 2.

After that, to the reset terminal R of R-S FF22,
By supplying the reset signal Sq from the terminal 23, the R-S FF 22 is reset, and the output signal So obtained at its output terminal Q has a low level l.
As a result, the operation mode control circuit 9 stops the reproduction operation state and returns to the initial state.

As described above, in the recording operation state in which a signal is recorded on the disk 1 in which the signal can be recorded optically, the spot on the disk 1 of the light beam from the optical head 2 incident on the disk 1 is
For example, even if the disk 1 is moved to a portion of the disk 1 where signals have already been recorded due to an external impact, the recorded contents of that portion will be prevented from being damaged.

Note that in the above example, it is assumed that not only the recording operation state for the disk but also the playback operation state can be taken, but the playback operation state is not assumed, and therefore, in the recording operation state. R-
When the output signal So from the output terminal Q of the S FF 22 takes a high level h, the recording operation on the disk may simply be stopped.

Effects of the Invention As is clear from the above description, according to the optical disk recording device according to the present invention, when a disk capable of optically recording signals is mounted and in a recording operation state, an impact is applied from the outside. Or, if the disk has a defect such as a scratch, and the light beam incident on the disk operates on that defect, the position of the light beam incident on the disk may be incorrect. Even if a situation occurs in which the disk is moved rapidly across the track to a portion where a signal has already been recorded, the situation is detected immediately before it occurs, and the recording operation to the disk is immediately aborted. It is possible to reliably avoid the inconvenience that, after the occurrence of signal recording, signal recording is performed in a portion where signal recording has already been performed, resulting in damage to the recorded contents. Furthermore, in order to detect a situation in which the arrival position on the disk of a light beam incident on the disk rapidly moves in a way that crosses a spiral track, the level of the signal corresponding to the tracking error is maintained by the level holding unit. This is performed in response to the detection output from the level comparison section obtained when the level range between the first reference level and the second reference level is exceeded, and in this case, the detection output of the first reference level and the second reference level is Both are set in advance in accordance with the respective disks based on the level of a signal corresponding to the tracking error obtained when the light beam incident on the disk moves in a direction across the spiral track. Therefore, it is possible to avoid erroneous detection caused by uneven characteristics between disks.

[Brief explanation of the drawing]

FIG. 1 is a block connection diagram showing an example of an optical disk recording device according to the present invention, and FIGS.
FIG. 4 is a waveform diagram used to explain the operation of the example shown in the figure. In the figure, 1 is a disk, 2 is an optical head, 3 is a light source, 4 is a signal forming circuit, 6, 11, and 12 are switches, 7 is a drive amplifier circuit, 8 is a drive coil for tracking adjustment, and 9 is an operation mode control circuit. , 13 is an upper peak level detection circuit, 14 is a lower peak level detection circuit, 15 and 16 are level holding circuits,
19 and 20 are level comparison circuits, 22 is R-S
It is FF.

Claims (1)

[Scope of Claims] 1. A signal forming unit that obtains a signal corresponding to a tracking error of a light beam incident on a disk on which a spiral track is formed and optical signals can be recorded; a light beam driver configured to move a light beam incident on the disk in a direction across the spiral track; and a light beam driver configured to move the light beam incident on the disk in a direction across the spiral track. a peak level detection section that is supplied with a signal corresponding to the tracking error obtained from the signal forming section when the movement is made, and detects an upper peak level and a lower peak level of the signal corresponding to the tracking error; , a level that maintains a first reference level slightly lower than the upper peak level detected by the peak level detector and a second reference level slightly higher than the lower peak level detected by the peak level detector. a holding section; during a recording operation in which a signal is recorded on the disk, a level of a signal according to a tracking error obtained from the signal forming section is set to the first reference level held by the level holding section; A level comparison section that generates a detection output when the level range between the second reference level and the second reference level is exceeded; and a state in which signal recording to the disk is stopped when the detection output from the level comparison section is obtained. An optical disk recording device comprising: an operation control section that controls the following;