JPS6142742A - Optical disk recording device - Google Patents

Abstract

PURPOSE:To evade the destruction of recorded contents without decreasing a recording capacity by obtaining two threshold voltages which vary stepwise according to whether the peak value of a tracking error signal is positive or negative from a tracking error signal. CONSTITUTION:A light beam from a laser light source 21 is reflected by a disk 10 and passed through a signal generating cirucit 31, phase compensating circuit 32, S terminal of SW33, and amplifying ciucuit 34 to obtain a tracking error signal TE and a playback output RE, and control is so carried out that the incidence position of a incident light beam on the disk 10 crosses a track, thus performing servo control. A switching control signal TR is held at a high level for a specific period prior to the recording of the signal, and the SW33 is changed over to a side T to allow the incidence position of the light beam on the disk 10 to move in the crossing direction of the track beyond a specific range without performing the servo control. Consequently, if the light is disordered as the device becomes out of the servo control, the recording of the signal to the disk is stopped and the contents of the recorded signal are prevented from being destroyed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides a method for recording signals by directing a light beam modulated by the signal onto an optical disc on which a user is able to optically record signals. The present invention relates to an optical disc recording 6 for recording.

7. Prior Art Optical discs, such as so-called DRAW discs, on which a user can optically record signals 7. However, in such a disk, a guide groove is generally provided in advance on the recording surface to define a spiral track, and in an optical disk recording device that records signals on this disk, the disk rotates. To the optical system that is moved in the radial direction of the disk and moved in the radial direction of the disk・2
A signal is recorded on the disc by irradiating the disc with a light beam modulated by the signal to be recorded by the disc, and in this case, the irradiation is performed on the disc in such a way that the signal is recorded on a preformed track on the disc. The positional deviation of the spot of the light beam on the disk with respect to the track is detected, and based on the tracking error signal, which is the detection signal, optical means such as an objective lens constituting the optical head or the entire optical head is detected. The incident position of the driven light beam that enters the disk is
Tracking servo control is performed to control the light beam that is moved in the direction across the track and is incident on the disk to scan over the track.

By the way, when a disc has a defect such as a scratch and the light beam incident on the disc scans the defect, or when an external shock is applied to the recording device or disc, tracking is disturbed and the light beam is affected. The incident position of the light beam on the disk is moved significantly in the direction across the track, the incident position of the light beam on the disk is returned to the area where the signal has already been recorded, and the signal recording operation is performed on that area.
There is a risk that the contents of the already recorded signal will be destroyed.

Therefore, by detecting whether or not the tracking error signal when recording signals on the disk becomes higher than a certain positive detection level and lower than a certain negative detection level, tracking is disturbed and light is detected. It is detected in advance that the incident position of the beam on the disk is moved significantly in the direction across the track, and when the tracking error signal becomes higher than a certain positive detection level and lower than a certain negative detection level, the disk The idea is to prevent the recording of signals to.

Problems to be Solved by the Invention However, the magnitude of the tracking error signal varies within a range of 6 dll depending on the disc on which the signal is recorded, and its positive and negative peak values vary, for example, by ±1. Varies within a range of ±0.5 V from Ov.

Therefore, if the tracking disturbance detection level is constant regardless of the disc as described above, tracking disturbance cannot be accurately detected regardless of the disc, and depending on the case, the following causing inconvenience. That is, based on the disk where the tracking error signal is minimum, its positive and negative peak values ±0
．． When setting ±0.4v, which is 80% of 5v, as the tracking disturbance detection level, when recording No. 13 on a disc where the tracking error signal is the maximum, the tracking disturbance detection level is the tracking error signal. The tracking error signal is only 40% of the positive and negative peak values of ±1.0μ, and tracking disturbances that are not a practical problem are detected, resulting in a decrease in the recording capacity of the disc. The positive and negative peak values are ±1.0■ based on the disk with the maximum
When setting the tracking disturbance detection level to ±0.8V, which is 80% of If the negative peak value becomes 160% of 0°5V, there is a risk that problematic tracking disturbances will not be detected and the contents of the already recorded signal will be destroyed as described above.

In view of the above, the present invention enables accurate detection of tracking disturbances regardless of the disk on which signals are to be recorded, and allows the contents of already recorded signals to be recorded without reducing the recording capacity of the disk. This is to avoid damage.

Means for Solving the Problems In the present invention, when the incident position of the light beam incident on the disk on which a signal is to be recorded is moved by one track or more in the direction across the tracks, First and second voltage generating sections are provided for obtaining first and second threshold voltages that are changed stepwise according to the positive and negative peak values of the tracking error signal; a plurality of voltage comparison circuits that sequentially compare the tracking error signal of the voltage generation section with different reference voltages in a stepwise manner, a plurality of holding circuits that hold the output of each voltage comparison circuit, and each holding circuit. The first and second threshold voltages obtained from the first and second voltage generators are combined with the above-mentioned tracking disturbance. detection level.

According to this, if the magnitude of the tracking error signal varies within a range of 66B depending on the disc on which the signal is to be recorded, such that its positive and negative peak values vary within the range of ±1.0V to ±065V. Then, when recording a signal on a disk where the tracking error signal is maximum, the tracking disturbance detection level is, for example, 65 of the positive and negative peak values of the tracking error signal ±i, o v.
%, and the tracking error signal is at its minimum.When recording a signal on a disk, the tracking disturbance detection level is ±0.5v of the positive and negative peak values of the tracking error signal, for example 78 ±0.39 of %
The detection level of the trough disturbance is about 60 to 80% of the positive and negative peak values, depending on the magnitude of the tracking error signal of the disk on which the signal is to be recorded. This makes it possible to accurately detect tracking disturbances regardless of the disc on which the signal is recorded.

Embodiment FIG. 1 shows an example of the optical disc recording device of the present invention, in which a disc 10 records signals by irradiating a light beam modulated by a signal onto a spiral track formed in advance as described above. The optical head 20 faces the disk 10, and the optical head 20
It is arranged so that it can move in the radial direction. The optical head 20 makes a light beam from a built-in laser light source 21 enter the disk 10, receives the light beam reflected by the disk 10 with a built-in optical part, and generates an electric signal according to the destination (). . The output signal of the optical part of the optical head 20 is supplied to a signal forming circuit 31, from which a tracking error signal TE and a reproduction output RF of the signal recorded on the track of the disk 10 are obtained.

The tracking error signal TE obtained from the signal forming circuit 31 is supplied to the terminal S of the switch 33 through the phase compensation circuit 32, and when the switch 33 is switched to the terminal S side, the tracking error signal TE is supplied to the drive amplifier circuit 34 through the switch 33. A drive signal is sent from the drive amplifier circuit 34 to the tracking error signal TE to the tracking drive coil 35.
and drives an optical means such as an objective lens built into the optical head 20 or the entire optical head 20 so that the incident position of the light beam incident on the disk 10 is moved in a direction across the track. Tracking servo control is then performed to control the light beam incident on the disk IO to scan over the track.

Prior to recording a signal on the disk 10, the switching control signal TR supplied from the system control circuit 40 to the switching control terminal of the switch 33 is kept high for a certain period of time as shown in the top row of FIG. During this period, the switch 33 is switched to the terminal T side, the above-mentioned tracking servo control is not performed, and the disk 10
The incident position of the light beam incident on the disk 10 is allowed to move beyond a certain range in the direction across the track. During this period, the system control circuit 4
The operation mode setting signal CS supplied from 0 to the operation mode control circuit 3G that controls the operation mode of the laser light source 21 of the optical head 20 is set to the first state, and the operation mode control circuit 36 outputs a certain amount A certain amount of the light beam is made incident on the disk 10. During this period, the track jump signal TJ is supplied from the system control circuit 40 to the terminal T of the switch 33, and by switching the switch 33 to the terminal T side, this track jump signal TJ is supplied to the drive amplifier circuit 34 through the switch 33. A drive signal is supplied from the drive amplification circuit 34 to the tracking drive coil 35 in addition to the track jump signal TJ, and a certain amount of light beam incident on the disk 10 is transmitted to the disk 10.
The incident position on the track is moved by one track in the direction across the track. Therefore, during the period in which the switching control signal TR is at a high level, the tracking error signal TE obtained from the signal forming circuit 31 changes sinusoidally as shown as the tracking error signal TEJ in FIG.

Here, the magnitude of the tracking error signal TEJ is, for example, 6d depending on the disc 1o on which the signal is to be recorded.
The positive and negative peak values vary within the range of B, and the positive and negative peak values vary from the main value of 1°0 when the tracking error signal TEJ is at its maximum, as shown by the solid line in FIG. 2, to the broken line in FIG. It changes within the main range of 0°5V at the minimum shown by.

This tracking error signal TEJ is supplied to the first and second voltage generators 60 and 70, and the first and second voltage generators 6o and 7o generate a tracking error signal T.
As for EJ, first and second threshold voltages v1 and V2 are obtained which can be changed stepwise according to its positive and negative peak values. This example is a case where the first and second threshold voltages 1 and V2 are changed in five steps depending on the positive and negative peak values of the tracking error signal TEJ.

That is, to explain the first voltage generating section 6o that obtains the first threshold voltage Vl corresponding to the positive peak value of the tracking error signal TEJ, the input terminal to which the tracking error signal TEJ is supplied and the -1, Ov A capacitor [C1 and a resistor R1 are connected in series between the terminal where the voltage of The positive peak value is 1. A tracking error signal TEX varying in the range from OV to Ov is obtained, and this tracking error signal TEX is sent to four voltage comparison circuits 88. 86. 84 and 82 as respective comparison inputs. Also, +1.
□ Five resistors of equal value RIO, RO8, R06, RO4,
RO2 is connected in series to resistor RIO and RO8, R
O8 and RO6, RO6 and R04, 'RO4 and RO
2 (7) Connection point ni o, 8 V.

0.6 V, 0.4 V, 0.2 V (7) voltages are obtained, and the voltages are 0.8 V, 0.6 V, 0.4 V
, the voltage of 0.2 V is the voltage comparator circuit 88.86,84
．． 82 as respective reference voltages. When the tracking error signal TEX serving as a comparison input is higher than the reference voltage, the voltage comparator circuits 88, 86, 84, and 82 output a high level, and the tracking error signal TE becomes high.
When X is below the reference voltage, the output is at a low level.

The output C8 of this voltage comparison circuit 88, 86, 84.82,
C6, C4, and C2 constitute the holding circuit, RS-free, differential-0:! Hupu 9B, 96, 94. ．． 92 set terminal S
, respectively, and the outputs C8, C6°C4, C2 rise from low level to high level, causing the RS flip-flops 98,96°94.92 to be sent, and the outputs Q8. Q6°C4 and C2 are set to high level. Note that the above-mentioned switching control signal TR is supplied from the system control circuit 40 to the reset terminals R of the RS flip-flops 9B, 96, 94.
B, 96, 94.92 are respectively reset, and their outputs Q8. Q6. Q4. Q2 are respectively brought to a low level.

The output Q8 of this RS flipflop 9B, 96.94°92. Q6. Q4. By adding Q2, an output threshold voltage ■1 is obtained. The adder circuit is, for example, an RS flip-flop 9B, 96.94.9
2 are connected to the inverting input terminal of the operational amplifier circuit 83 via resistors R8, R6, R4, and R2, respectively, and a resistor R3 is connected between the output terminal of the operational amplifier circuit 83 and the inverting input terminal.
is connected, the output terminal of the operational amplifier circuit 83 is connected to the inverting input terminal of the operational amplifier circuit 87 via the resistor R5, and the resistor R7 is connected between the output terminal and the inverting input terminal of the operational amplifier circuit 87, A bias voltage VB is supplied to the non-inverting input terminal of the operational amplifier circuit 87 to configure it. - As an example, the high level voltage of the output Q8° C6, C4, C2 of the RS flip-flops 98, 96, 94.92 is 12V,
The resistances R8, R6, R4, and R2 are selected to be 470Ω, the resistance R3 is selected to be 5.1Ω, the resistors R5 and R7 are selected to be 10Ω, and the bias voltage VB is selected to be 0.39V.

According to the above, the positive peak value of the tracking error signal TEJ is higher than 0.9■<1.0V, and the positive peak value of the tracking error signal TEX is higher than 0.8■<1.0V.
1.0. When the voltage is below V, the voltage comparator circuits 8B, 86, 8
4.82 outputs CB, C6, C4, and C2 all become high level during a part of the high level period of the switching control signal TR as shown in FIG.
96.94°92 output Q8. Q6. Q4. As shown in FIG. 2, Q2 becomes high level after the time period during which the switching control signal TR is at a high level, and the output voltage VA of the operational amplifier circuit 83 becomes as shown in FIG. The first threshold voltage v1, which is the output voltage of the circuit 87, is 0.65V as shown in FIGS. 2 and 3. The positive peak value of the tracking error signal TEJ is higher than 0.8 V<0.9V, and the positive peak value of the tracking error signal TEX is higher than 0.6V<0.8
V or less, the output terminals C6, C4°C2 of the voltage comparison circuits 86, 84.82 become high level during a part of the high level period of the switching control signal TR, and the RSS flip-flops 9.94. 92 output Q6. Q4. Q2 becomes high level after the time within the period of the low level of the switching control signal TR, and the first threshold voltage v1 becomes 0.585 V as shown in FIG. The positive peak value of the tracking error signal TEJ is higher than 0°7v <0.8V
In the following, when the positive peak value of the tracking error signal TEX is higher than 0.4V and lower than 0.6V, the outputs C4 and C2 of the voltage comparator circuit 84.82 are in the high level period of the switching control signal TR. The output Q4 of the RS flip-flops 94 and 92 becomes high level for a part of the period. Q2 becomes high level after the time period during which the switching control signal TRO is at high level, and the first threshold voltage 1 becomes 0.52V as shown in FIG. Tracking error signal T
The positive peak value of EJ is higher than 0.6V and less than 0.7V, and the positive peak value of tracking error signal TEX is 0.
When the voltage is higher than 2 V and less than 0.4 V, the voltage comparator circuit 8
Only the output C2 of the RS flip-flop 92 becomes high level during a part of the high level period of the switching control signal TR, and only the output C2 of the RS flip-flop 92 becomes high level after the point in time during the high level period of the switching control signal TR. It becomes a high level, and the first threshold voltage 1 becomes 0.455V as shown in FIG. When the positive peak value of the tracking error signal TEJ is 0.5V or more and 0.6V or less, and the positive peak value of the tracking error signal TEX is 0V or more and 0°2V or less, the voltage comparison circuits 88', 86, 84.82 output CB
+ C6, C4 + C2 remains at a low level, and the RS flip-flop 98.96.94.92
Output Q8. Q6. Q4°C2 remains at a low level and the first threshold voltage ■1 becomes 0.39V as shown in FIG.

The second voltage generating section 70 that obtains the second threshold voltage V2 corresponding to the negative peak value of the tracking error signal T E has a similar configuration, and as shown in FIG. 3, the tracking error signal TBJ The negative peak value of -0,9
■When the voltage is lower than -1,0■ or more, the second threshold voltage JEV2 becomes -0,65V, and the negative peak value of the tracking error signal TEJ is lower than -0,8V.
When it is 0.9■ or more, the second threshold voltage ■2
If it becomes -0,585V, the tracking error signal TE
When the negative peak value of J is lower than -0.7■ and greater than -0.8■, the second threshold voltage ■2 is -0.52
When the negative peak value of the tracking error signal TEJ is lower than -0.6V and greater than or equal to -0.7V, the second threshold voltage 2 becomes -0.455V, and the tracking error signal TEJ The negative peak value of -0,5
When the voltage is below -0 and 6■, the second threshold voltage (2) becomes -0.39V.

The first threshold voltage (1) obtained from the first voltage generator 60 is supplied to the negative input terminal of the voltage comparison circuit 51. Further, the second threshold voltage v2 obtained from the second voltage generating section 70 is supplied to the positive input terminal of the voltage comparison circuit 52.

When the switching control signal TR is inverted from high level to low level, the system control circuit 40 selects the operation mode 111.
The operation mode setting signal C3 supplied to the control circuit 36 is set to the second state, and the operation mode control circuit 36 causes the laser light source 21 to emit a light beam modulated by the recording signal R3 supplied from the input terminal 37. A light beam modulated by the recording signal R3 enters the disc 10, and the switch 33 is switched to the terminal S side, the above-mentioned tracking servo control is performed, and recording is performed on the track on the disc 10. Signal R3 is recorded.

In this state, the tracking error signal TE obtained from the signal forming circuit 31 is specifically converted into a tracking error signal T.
If ER, the switching control signal TR is supplied from the system control circuit 40 to the switching control terminal of the switch 39, and when the switching control signal TR is inverted from high level to low level, the switch 39 is switched from off to on, and tracking is performed. The error signal TER is supplied to the positive input terminal of the voltage comparator circuit 51 and the negative input terminal of the voltage comparator circuit 52 through the switch 39, and in the voltage comparator circuit 51, the trunking error signal TER is supplied from the first threshold voltage ■1. It is detected whether the voltage becomes high or not, and the voltage comparison circuit 5
2, it is detected whether the tracking error signal TER becomes lower than the second threshold voltage v2. Then, the outputs S1 and S of the voltage comparison circuits 51 and 52
2 is supplied to the OR gate 53, the output S3 of the OR gate 53 is supplied to the set terminal S of the RS flip-flop 54, the stop control signal SQ is supplied from the system control circuit 40 to the reset terminal R of the RSS flip-flop 5, and the RS flip-flop The output SO of the flip-flop 54 is supplied to the operating mode control circuit 36.

When the tracking error signal TER is below the first threshold voltage 1 and above the second threshold voltage 12, the outputs SL and S of the voltage comparison circuits 51 and 52 are
2 are both low level, and the output S3 of Agate fi3 is low level, but the tracking error signal TE
When R becomes higher than the first threshold voltage v1, the output S1 of the voltage comparator circuit 51 becomes high level, and the tracking error signal TER rises to the second threshold voltage v
When the voltage becomes lower than 2, the output S2 of the voltage comparator circuit 52 becomes high level. Therefore, when the tracking error signal TER becomes higher than the first threshold voltage 1 and lower than the second threshold voltage v2, the output S3 of the OR gate 53 becomes high level, and its rise causes the RSS flip-flop to When the output signal R3 is sent, its output SO becomes high level, and this causes the operation mode control circuit 36 to be in a state where, for example, the laser light source 21 does not emit a light beam, thereby preventing the recording signal R3 from being recorded on the disk 10. Ru. After recording is blocked in this way, when the stop control signal SQ is reversed from low level to high level,
The rising edge resets the RS flip-flop 54, causing the output SO of the RS flip-flop 54 to return to a low level, thereby returning the operating mode control circuit 36 to its initial state.

The magnitude of the tracking error signal TEH is disk 10.
The first and second threshold voltages vl and v, which are tracking disturbance detection levels, vary depending on
2 is also changed by the disk 10 as described above, so that tracking disturbances can be accurately detected regardless of the disk 10, i.e., regardless of the disk 10, it can be ensured that only when the tracking is disturbed so much that the servo is dislocated. The output S3 of the OR gate 53 becomes high level, and recording of the recording signal R3 onto the disk 10 is prevented. Tracking error signal TE in the lower part of Fig. 2
The solid line R indicates the case where the disk 10 has a tracking error signal TEJ whose positive peak value is higher than 0.9 V and whose negative peak value is lower than -0.9 V. In this case, Output si of voltage comparison circuits 51 and 52
and S2, the output S3 of the OR gate 53, and the output SO of the RS flip-flop 54 are shown by solid lines, respectively, when the tracking error signal TER becomes higher than 0.65V and lower than -0,65V, the recording signal R5 Recording on the disc 10 is prevented. What is indicated by the broken line of the tracking error signal TER is when the disk 10 has a positive peak value of the tracking error signal TEJ of 0.6v or less and a negative peak value of -0°6v or more. When the tracking error signal TER becomes higher than 0.39V, as shown by the broken lines of the outputs S1 and S2 of the voltage comparison circuits 51 and 52, the output S3 of the OR gate 53, and the output SO of the RSS flip-flop 5, respectively, When the recording signal R becomes lower than -0.39V,
3 is prevented from being recorded on the disk 10.

Effects of the Invention According to the present invention, the positive and negative values are determined from the tracking error signal when the incident position of the light beam incident on the disc on which a signal is to be recorded is moved over one track or more in the direction across the tracks. First and second threshold voltages are obtained that can be changed stepwise according to the negative peak value, and these first and second threshold voltages are used as tracking disturbance detection levels. Regardless of the disc you are trying to record on,
When a disc has a defect such as a scratch and the light beam incident on the disc scans the defect, or when an external impact is applied to the recording device or disc, and tracking is disturbed so much that the servo becomes disconnected. Only then can recording of signals on the disk be reliably prevented, and damage to the contents of already recorded signals can be avoided without reducing the recording capacity of the disk.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of an example of the optical disc recording device of the present invention, and FIGS. 2 and 3 are diagrams for explaining its operation and first and second threshold voltages. In the figure, 10 is a disk, 20 is an optical head, 21 is a laser light source, 31 is a signal forming circuit, 35 is a tracking drive coil, 36 is an operation mode control circuit, 37 is an input terminal for recording signals, 40 is a system control circuit, 51 and 52 are voltage comparison circuits, 60 and 70 are first and second voltage generation sections, 88° 86.84.82 are voltage comparison circuits, 9
B, 96°94.92 is an RS flip-flop as a holding circuit, and 83 and 87 are operational amplifier circuits forming an adder circuit.

Claims (1)

[Claims] A signal can be recorded by irradiating a preformed track with a light beam modulated by a signal.The incident position of the light beam incident on the disc is moved in the direction across the track by one track or more. The first and second tracking error signals are changed stepwise according to their positive and negative peak values.
first and second voltage generators that obtain a threshold voltage; and whether a tracking error signal when recording a signal on the disk becomes higher than the first threshold voltage; detecting whether the voltage is lower than a threshold voltage, and preventing recording of a signal on the disk when the voltage is higher than the first threshold voltage and when the voltage is lower than the second threshold voltage; a plurality of voltage comparison paths in which the first and second voltage generation sections respectively compare the tracking error signal with different reference voltages in a stepwise manner;
An optical disc recording device comprising a plurality of holding circuits that hold the output of each voltage comparison circuit, and an adding circuit that adds the outputs of each holding circuit to obtain an output threshold voltage.