JP2000222730A - Recording power correction device - Google Patents

Abstract

(57) [Summary] [Problem] To follow the intensity of a recording laser beam irradiated at the time of data recording on a write-once optical disc, following dirt such as a fingerprint attached to a recording surface, and following the recording surface deviation. Control so that the data recording state on the optical disk is always optimal and stable. SOLUTION: A semiconductor laser diode 101 for irradiating a first laser beam and a second laser beam, and a servo / RF for receiving reflected light from a write-once optical disc and outputting an electric signal indicating the reflected light intensity A photodiode 104;
A B value detection circuit 105 for detecting a B value of the reflected light;
A DRC detection circuit 106 for detecting a signal, and a fingerprint detection circuit 107 for detecting dirt such as a fingerprint based on the DRC signal.
, RO value based on the B value and the output of the fingerprint detection circuit 107.
An ROPC loop filter circuit 108 that selects a control speed and a control frequency band of the PC and outputs a gain.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an apparatus for stably recording a data signal on a write-once optical disc.

[0002]

2. Description of the Related Art CD-R (Compact Disc-Recordable)
When recording data signals on write-once optical disks such as
Generally, a CIRC (Cross Interleaved Reuse) is added to a data signal.
The parity is added for error correction based on the ad-Solomon Code) and the signal is further converted to EFM (Eight to
Fourteen Modulation) is used. The modulated signal has nine time widths 3T to 11T obtained by multiplying a predetermined reference time width T by 3 to 11 as a high-level or low-level time width of the signal.
Is given. Based on this signal, for example, when the signal is at a high level, the write-once optical disc is irradiated with pulsed laser light to form pits on the recording layer of the write-once optical disc. Thus, the data signal is recorded on the write-once optical disc.

In performing the above signal recording, before irradiating the recording layer of the write-once optical disc with a laser beam, the recording laser beam intensity optimization (Optimum Power Calibration;
"PC". )I do.

[0004] Generally, a write-once optical disc has a power calibration area (Power Cali- bration) for performing OPC.
bration Area, hereinafter referred to as “PCA”. )have. The PCA has a test area and a count area, each of which has 100 partitions, and one partition of the test area has 15 frames.

[0005] OPC is performed by recording a predetermined signal on the PCA and reproducing the recorded signal. In the Orange Book, which is a standard for write-once optical discs, for example, pits are formed using 15 levels of laser light intensity for 15 frames, and the laser light intensity with the best recording state is detected, A method of recording a data signal by light intensity is described.

[0006] In a state where a data signal is recorded on the recording layer of the write-once optical disc, running OPC (hereinafter referred to as "ROPC") is performed. ROPC is the above OP
In order to keep the optimum laser beam intensity obtained by C constant during the data signal recording state, the reflected light intensity of the pits at the time of the OPC and at the time of data signal recording is compared, and based on the result, a laser beam is irradiated. The light intensity is corrected at any time. The pit used to detect the reflected light intensity is:
It has a time width of 11T, and the reflected light intensity at the rear end of the pit is used. This reflected light intensity is called a B value.

FIG. 9 is a diagram for explaining the relationship between the laser beam irradiated on the write-once optical disc and the reflected light.
9A shows the waveform of the laser light output, and FIG. 9B shows the waveform of the reflected light intensity.

For example, the light intensities k1, k2, k3, k4
When pits are formed by irradiating the write-once optical disc with five stages of laser light of k5 (FIG. 9A), the respective reflected light levels have waveforms k'1, k'2, k'3, k'4. , K'5
(FIG. 9B). The waveform of the reflected light level is high at the start end of the pit, then gradually decreases, and converges to a constant value near the end. This is because the pits formed on the write-once optical disc are gradually formed after receiving the laser beam, and the reflected light due to the pits gradually decreases. Therefore, in order for the reflected light level to converge to a constant value, it is necessary that the pit is a sufficiently long pit such as a pit having a time width of 11T. For example, the reflected light level from a short pit such as a pit having a time width of 3T is Does not converge even at the end of the pit. This converged reflected light level is B
And the B value changes according to the intensity of the laser beam emitted for forming the pits. By controlling the laser beam intensity so that the B value becomes an optimum value, the recording state on the write-once optical disc can be optimized.

FIG. 10 is a block diagram for explaining a conventional recording power correction apparatus. In the figure, 200
Is the above-described recording power correction device, calculates the B value from the reflected light of the recording laser light applied to the write-once optical disc,
The irradiation intensity of the laser light is controlled based on the B value.

The recording power correction device 200 includes a semiconductor laser diode 201 for irradiating a write-once optical disc with recording or reproduction laser light, and a part of the laser light for monitoring the irradiation intensity of the laser light. And a monitoring photodiode 202 for receiving the output and outputting an electric signal corresponding to the light intensity, and an APC (Automati
c Power Control) circuit 203, a servo / RF photodiode 204 that receives reflected light generated from the laser light from the write-once optical disc and outputs an electric signal corresponding to the reflected light intensity, and receives the electric signal. It comprises a B value detection circuit 205 for detecting a B value, and a ROPC loop filter 206 for setting a gain based on the B value.

Hereinafter, the operation of the recording power correction apparatus 200 will be described. Semiconductor laser diode 201
Irradiates a write-once optical disc with a recording laser beam having an optimum light intensity obtained by OPC. The monitoring photodiode 202 receives a part of the laser light, converts its intensity into an electric signal, and outputs the electric signal to the APC circuit 203. APC
The circuit 203 receives the output and controls the semiconductor laser diode 201 so that the laser beam of the optimum intensity becomes constant.

[0012] Servo / RF photodiode 204
Receives reflected light from a write-once optical disc generated by a recording laser beam, converts the reflected light intensity into an electric signal, and outputs the electric signal. The B value detection circuit 205 receives the output and detects a B value from the waveform of the reflected light. ROPC loop filter 206 outputs a gain based on the difference between the B value and the target value. The APC circuit 203 updates the target value of the light intensity of the recording laser light based on the gain. This allows
The intensity of the recording laser light emitted from the semiconductor laser diode 201 is controlled so that the B value becomes a predetermined target value.

As described above, the recording power correction device 20
According to 0, the intensity of the recording laser light emitted from the semiconductor laser diode 201 is controlled so that the B value detected from the reflected light of the write-once optical disc always becomes a target value. During the recording state, even when factors such as a change in laser light intensity due to a temperature change of the semiconductor laser diode, a change in the shape of the write-once optical disc, or a change in the recording sensitivity of the disc recording layer follow these, Stable data recording can be performed.

[0014]

The recording surface of a write-once optical disc may be stained by fingerprints or the like when the disc is handled. This can also cause a change in the data recording state, so it is necessary to control the recording laser beam intensity for these stains to optimize the data recording state. Generally, in order to control the intensity of a laser beam applied to an optical disc so as to follow dirt on a disc recording surface, ROPC
It is necessary to make the control characteristics of the device high speed and wide band. Normal,
Since dirt such as fingerprints has a size of several mm to several tens of mm, the linear velocity at which a write-once optical disc is traced is set to 1.
When the speed is 2 m / s, the time during which 1 mm of dirt is affected is about 0.83 ms. In order to change the recording power and maintain the optimum recording state in response to such contamination, it is necessary to control the ROPC at a high speed of about several kHz and in a wide band.

However, when the control characteristic of the ROPC is set to a high speed and a wide band, the fluctuation of the B value caused by the recording surface deviation which is inevitable in the molding accuracy of the disk can be followed.
There is a problem that ROPC cannot be performed stably.

FIG. 11 is a diagram for explaining the B value, recording power, and reproduction RF signal envelope when the control band of ROPC is narrow. FIG. 11 (a) shows the fluctuation of the B value, which fluctuates with one rotation of the disk due to the fluctuation of the recording surface of the write-once optical disk. FIG. 11 (b) shows the fluctuation of the recording power. Since the recording power has a narrow control band of ROPC,
A constant value is maintained without following the fluctuation of the B value. FIG. 11 (c) shows the fluctuation of the reproduction RF envelope. Since the recording power of the reproduction RF envelope keeps a constant value and the recording state does not fluctuate, there is no fluctuation due to disk rotation.

FIG. 12 is a diagram for explaining the B value, recording power, and RF signal envelope when the control band of ROPC is wide. FIG. 12 (a) shows the fluctuation of the B value, which fluctuates in a cycle of one rotation of the disk due to the fluctuation of the recording surface of the write-once optical disk, similarly to FIG. 11 (a). . FIG. 12B shows the fluctuation of the recording power. The recording power follows the fluctuation of the B value because the control band of the ROPC is sufficiently wide with respect to several Hz of the recording surface blur component. Fluctuating. FIG. 12C shows the fluctuation of the reproduction RF envelope, and the reproduction RF envelope fluctuates in accordance with the fluctuation of the recording power.

As described above, when the control characteristic is set to a high speed and a wide band in order to make the ROPC cope with stains such as fingerprints, the intensity of the recording laser beam follows the fluctuation of the B value due to the fluctuation of the recording surface of the optical disk. Fluctuates, and on the contrary, the recording state becomes unstable.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has an advantage that the intensity of a recording laser beam irradiated at the time of recording data on a write-once optical disc follows dirt such as a fingerprint attached to a recording surface, and It is an object of the present invention to provide a recording power correction device which controls so as not to follow a recording surface deviation or the like, thereby always making an optimal and stable data recording state on an optical disk.

[0020]

A recording power correction apparatus according to the present invention (claim 1) forms pits on an optical disc on which data is recorded based on the presence or absence of pits formed on a track groove based on recording data. By irradiating a first laser beam having a laser beam intensity and a second laser beam having an intensity that does not form pits, the optical disc apparatus is provided with a laser beam irradiating means for recording the recording data on the optical disc. A recording power correction device for receiving reflected light of the first or second laser light generated by the optical disk and outputting a reflected light intensity signal representing the intensity of the reflected light; A pit reflected light detecting means for outputting a first signal representing a reflected light intensity of the rear end of the pit based on the light intensity signal, and a reflected light intensity signal of the second laser light, A track detecting means for outputting a second signal indicating whether or not the laser beam is irradiated on the track groove of the optical disc; and a fingerprint on the track groove of the optical disc when the second signal is equal to or more than a predetermined threshold value. Alternatively, a fingerprint detecting means for outputting a third signal indicating that there is dirt, and following the change of the first signal due to the fingerprint or dirt when the third signal indicates that there is fingerprint or dirt. Control means for outputting a control signal for controlling the irradiation intensity of the first laser light.

According to a second aspect of the present invention, in the recording power correction apparatus according to the first aspect, the control means includes:
When the third signal indicates that there is a fingerprint or a stain, the control signal is output at a higher speed and a wider band than a predetermined control characteristic.

Further, according to the present invention (claim 3), in the recording power correction apparatus according to claim 1, the control signal is:
This is for directly correcting the value of the current flowing through the laser beam irradiation means.

According to a fourth aspect of the present invention, in the recording power correction apparatus according to any one of the first to third aspects, the laser light irradiating means irradiates the track groove of the optical disk with the second laser light. A first light emitting element that emits light and a second laser light that irradiates a second laser beam between track grooves of the optical disc.
A first light-receiving element for receiving reflected light of the optical disk generated by the first light-emitting element and outputting a reflected light intensity signal representing the light intensity; and a second light-receiving element. A second light receiving element for receiving the reflected light of the optical disk generated by the light emitting element and outputting a reflected light intensity signal representing the light intensity, wherein the track detecting means includes a reflected light output by the first light receiving element. The second signal is output based on the intensity signal and the reflected light intensity signal output by the second light receiving element.

According to a fifth aspect of the present invention, in the recording power correction apparatus according to any one of the first to fourth aspects, the laser beam irradiating means receives the second laser beam, and the light intensity of the second laser beam is received. And a control circuit for receiving the light intensity signal and controlling the irradiation intensity of the second laser light, and keeping the irradiation intensity of the second laser light constant. Is what you do.

[0025]

Embodiments of the present invention will be described below. (Embodiment 1) FIG. 1 is a block diagram showing a configuration of a recording power correction apparatus according to Embodiment 1 of the present invention. In the figure, reference numeral 100 denotes the above-described recording power correction device, which is a semiconductor that irradiates a first laser beam having a light intensity that forms a pit on a write-once optical disc and a second laser beam having a light intensity that does not form a pit. It is connected to an optical disk device (not shown) having a laser diode 101.

The recording power correction device 100 receives a part of the first laser light and outputs an electric signal indicating the light intensity. A to control the first laser beam intensity to be irradiated to maintain a target value.
A PC circuit 103; a servo / RF photodiode 104 for receiving reflected light from a write-once optical disc generated by a recording or second laser beam and outputting an electric signal indicating the reflected light intensity; and a first laser beam A B-value detection circuit 105 that receives an electric signal based on the second laser beam and receives an electric signal based on the second laser beam and receives a DRC (Differ
DRC detection circuit 106 for detecting an ntial radial contrust signal, a fingerprint detection circuit 107 for detecting dirt such as a fingerprint based on the DRC signal, a B value and fingerprint detection circuit 107
And a ROPC loop filter circuit 108 that selects a control speed and a control frequency band of the ROPC based on the output of the ROPC and outputs a gain.

Hereinafter, the detailed configuration of the recording power correction apparatus 100 will be described. FIG. 2 shows the DRC circuit 1
FIG. 12 is a diagram showing a configuration of a peripheral circuit 06 and peripheral circuits thereof. In the figure, Tr is a track groove of a write-once optical disc. The track groove Tr has a main beam Mb for recording or irradiating a second laser beam and sub-beams Sb1 and Sb2 for detecting a track or focus error. Has been irradiated. Main beam Mb and sub beams Sb1, Sb2
Are arranged such that their irradiation positions are shifted by half the width between the track grooves. That is, the irradiation position of the main beam Mb is at the center of the track groove Tr, the irradiation position of the sub beam Sb1 is between the track grooves on one end side of the track groove Tr, and the irradiation position of the sub beam Sb2 is the track groove on the other end side of the track groove Tr. The servo / RF photodiode 104 disposed between the main beam photodiode 41 receives the reflected light of the main beam Mb and outputs an electric signal indicating the light intensity, and the reflection of the sub beam Sb1. A sub-beam photodiode 42 for receiving light and outputting an electric signal representing the light intensity
And a sub-beam photodiode 43 that receives the reflected light of the sub-beam Sb2 and outputs an electric signal indicating the light intensity.

The main beam photodiode 41
Is a four-division photodiode, which outputs signals A, B, C, and D based on the light intensity received by each. On the other hand, the sub-beam photodiodes 42 and 43
Is a two-division photodiode which outputs signals E and F based on the reflected light of the sub-beam Sb1 and signals G and H based on the reflected light of the sub-beam Sb2.

The DRC circuit 106 includes a sample / hold circuit 61a for holding the signal A, a sample / hold circuit 61b for holding the signal B, a sample / hold circuit 61c for holding the signal C, and a sample / hold circuit 61d for holding the signal D. A sample and hold circuit 61e for holding the signals E and G, a sample and hold circuit 61f for holding the signals F and H, an adder 62a for adding the output of the sample and hold circuit 61a and the output of the sample and hold circuit 61b, Adder 6 for adding the output of sample hold circuit 61c and the output of sample hold circuit 61d
2b, an adder 62c for adding the output of the sample and hold circuit 61b and the output of the sample and hold circuit 61c
An adder 62d for adding the output of the sample and hold circuit 61b to the output of the sample and hold circuit 61d; an adder 62e for adding the output of the adder 62a to the output of the adder 62b; A subtractor 63a for subtracting the output of the adder 62d, a subtractor 63b for subtracting the output of the adder 62a and the output of the adder 62b, and subtracting the output of the sample hold circuit 61e and the output of the sample hold circuit 61f. Subtractor 63c, the output of sample and hold circuit 61e and sample and hold circuit 61f
Adder 62f that adds the output of the adder 62f, an amplifier circuit 64 that amplifies the output of the adder 62f, an amplifier circuit 65 that amplifies the output of the subtractor 63c, and the output of the adder 62e and the output of the amplifier circuit 64. Subtractor 63d for subtracting
subtracter 63 for subtracting the output of the amplifier circuit 65 from the output of b.
e.

On the other hand, the B value detection circuit 105 outputs the output signals A, B, C, D of the main beam photodiode 41.
, And a sample-and-hold circuit 52 that holds the output of the adder 51.

FIG. 3 is a block diagram showing the configuration of the fingerprint detection circuit 107. In the figure, the fingerprint detection circuit 1
Reference numeral 07 denotes a window comparator 71 which receives a DRC signal and outputs a DRC compare signal when the DRC signal exceeds a predetermined threshold value, and removes and outputs Lo pulses of a predetermined time or less from the DRC compare signal. And a one-shot multivibrator 72.

FIG. 4 shows the APC circuit 103 and the ROP
FIG. 3 is a block diagram showing a configuration of a C loop filter circuit 108. In the figure, the APC circuit 103 includes a recording power target value storage circuit 31 for holding a target recording power.
And the output of the recording power target value storage circuit 31 and ROPC
An adder 32 for adding the output of the loop filter 83,
The output of the adder 32 and the monitoring photodiode 102
, A WAPC loop filter for controlling the output of the subtractor 33 with a predetermined frequency characteristic, and an output of the WAPC loop filter and an output of the recording current correction circuit 84. And an adder 35.

The above ROPC loop filter circuit 1
08 is a B value target value storage circuit 81 for holding a target B value, a subtracter 82 for subtracting the output of the B value target value storage circuit 81 and the output of the B value detection circuit 105, and a fingerprint detection circuit An ROPC loop filter 83 that switches its control characteristic from low-speed and narrow-band to high-speed and wide-band based on the output of 107, and a recording current correction circuit 84 that corrects the recording current based on the output of the ROPC loop filter 83. ing.

FIG. 8 is a block diagram showing a detailed configuration of the recording power correction apparatus of FIG.
Reference numeral 11 denotes a digital APC circuit.
03 is equivalent to 112, and 112 is a digital ROPC
This is a loop filter circuit corresponding to the ROPC loop filter circuit 108, and performs processing by a digital signal.

The digital APC circuit 111 includes a recording power target value storage circuit 1 for holding a target recording power.
1, an adder 12 that adds the output of the recording power target value storage circuit 31 and the output of the digital ROPC filter circuit 112, a recording power setting limiter 13 that limits the added value so as not to exceed a setting limit, A subtractor 14 for subtracting the output of the recording power setting limiter 13 from the output of the monitor photodiode 102 which has been digitally converted.
A multiplier 15a for multiplying the output of the subtracter 14 by a filter constant, an adder 15c for adding the output of the multiplier 15a and the output of the multiplier 15b, and adding a delay to the output of the adder 15c. A unit delay unit 15d, and the delay unit 1
A multiplier 15b for multiplying the output of 5d by a filter constant;
Recording current reference value storage circuit 16 for holding the recording current reference value
And the output of the recording current storage circuit 16 and the digital ROPC
An adder 17 for adding the output of the filter circuit 112,
A recording current setting limiter 18 for limiting the output of the adder 17 so as not to exceed a predetermined setting limit, and an adder 19 for adding the output of the recording current setting limiter 18 and the output of the adder 15c. I have. Note that the multiplier 15a
, A multiplier 15b, an adder 15c, and a unit delay unit 15d to form a first-order IIR digital filter, and frequency characteristics can be switched by switching constants of the multipliers 15a and 15b. .

The digital ROPC filter circuit 112 includes a B value target value storage circuit 21 for holding a target B value, and an output of the B value target value storage circuit 21 and a digitally converted B value detection circuit 105. , A multiplier 22a for multiplying the output of the subtracter 22 by a filter constant, and an output of the multiplier 22a and the multiplier 22.
b, an adder 22c for adding a delay to the output of the adder 22c, and a multiplier 22b for multiplying the output of the delay 22d by a filter constant
And a recording current correction circuit 23 for correcting the recording current based on the output of the adder 22c. Note that the multiplier 22a, the multiplier 22b, the adder 22c, and the unit delay unit 22d constitute a first-order IIR digital filter, and the frequency characteristics are switched by switching the constants of the multiplier 22a and the multiplier 22b. Can be done.

Next, the operation will be described. A semiconductor laser diode 101 irradiates a write-once optical disc with a laser beam for recording based on recording data to be recorded on the optical disc, and a monitor photodiode 102 receives a part of the laser beam and its light intensity. The electrical signal corresponding to
Output to the PC circuit 103. The APC circuit 103 receives the electric signal and holds the first laser light intensity irradiated by the semiconductor laser diode at a target value. On the other hand, the servo / RF photodiode 104 receives the reflected light from the write-once optical disc generated by the second laser light, and outputs an electric signal corresponding to the light intensity. The DRC detection circuit 106 receives the electric signal and detects a DRC signal.

Hereinafter, detection of the DRC signal will be described. In FIG. 2, the photodiode 4 for the main beam is used.
Numeral 1 receives the disk reflected light generated by the second laser light of the main beam Mb, and outputs the electric signals A, B, C, and D corresponding to the light intensity, respectively, to the four-division photodiodes. On the other hand, the sub-beam photodiode 4
Reference numerals 2 and 43 respectively receive the disk reflected light of the sub-beams Sb1 and Sb2, and output electric signals E, F or G and H corresponding to the light intensities of the photodiodes into two parts. Signals A, B, C, and D are sampled and held by sample and hold circuits 61a, 61b, 61c, and 61d, respectively, signals E and G are sampled and held by sample and hold circuit 61e, and signals F and H are sampled and held by sample and hold circuit 61f. You.

FIG. 5 is a diagram for explaining the details of the sample hold. FIG. 5A shows an optical output waveform of a laser beam applied to a write-once optical disc. The semiconductor laser diode 101 irradiates the optical disc based on recording data to be recorded on the optical disc. The main beam Mb irradiates a first laser beam having a high light output in a section where a pit is formed on the recording layer of the disc, and irradiates a second laser beam having a low light output in a section where no pit is formed. I have. FIG. 5B shows the waveform of the reflected light from the disk. The intensity of the reflected light is high at the starting point of the pit, then gradually decreases, and converges to a constant value near the end.
FIG. 5C shows a sample-and-hold circuit control signal, which is Hi during the section where the second laser beam is irradiated.
, And becomes Lo in the section where the first laser light is irradiated, and holds the disk reflected light (FIG. 5B). The position at which the sample-and-hold circuit control signal transitions from Lo to Hi is determined by the response (R1, R) of the disk reflected light (FIG. 5B) generated at the time of transition from the first laser light to the second laser light.
2, R3) is provided with a slight delay from the position where the laser light transitions. In this way, the disk reflected light when the second laser light is irradiated is sampled and held.

By the above sample hold, the sample hold circuit 61a receives the signal A ', the sample hold circuit 61b receives the signal B', the sample hold circuit 61c receives the signal C ', the sample hold circuit 61d receives the signal D',
The sample and hold circuit 61e samples and holds the signal EG ', and the sample and hold circuit 61f samples and holds the signal FH'. The adder 62c adds the signal A 'and the signal C', the adder 62d adds the signal B 'and the signal D', and
3a calculates the focus error signal {(A '+ C')-(B '+ D')} by subtracting the addition signal (A '+ C') from the addition signal (B '+ D').

The adder 62a adds the signal A 'and the signal B', the adder 62b adds the signal C 'and the signal D', and the subtractor 63b adds these signals (A '+ B').
And the addition signal (C ′ + D ′). On the other hand, the subtractor 63c subtracts the signal EG 'and the signal FH', and the amplifier circuit 65 multiplies the subtracted signal (EG'-FH ') by Q times. The subtractor 63e subtracts the output of the subtractor 63b and the output of the amplifier circuit 65 to obtain a track error signal ｛(A ′ + B ′) − (C ′ + D ′) − Q (EG′−F).
H ′) is calculated.

The adder 62e adds the addition signal (A '+ B') and the addition signal (C '+ D'). On the other hand, the adder 62f adds the signal EG 'and the signal FH', and the amplifying circuit 64 adds this signal (EG '+ F
H ') is multiplied by P times. The subtractor 63d is connected to the adder 62e.
Is subtracted from the output of the amplifying circuit 64 to obtain DR
C signal ｛(A ′ + B ′ + C ′ + D ′) − P (EG ′ + F
H ′) is calculated.

The DRC signal is obtained by subtracting the reflected light amounts of the sub beams Sb1 and Sb2 from the reflected light amount of the main beam Mb. Usually, the sub beams Sb1 and Sb2 are
Since the light amount is smaller than that of the main beam Mb, the electric signal is amplified P times by the amplifier circuit 64. P is calculated from the light amount ratio between the main beam Mb and the sub beams Sb1 and Sb2.

When the reflectivity of the area irradiated with the main beam Mb is equal to the reflectivity of the area irradiated with the sub beams Sb1 and Sb2, the DRC signal becomes zero. When the reflectivity of the area irradiated with the main beam Mb is smaller, the DRC signal is negative. Conversely, when the reflectivity of the area irradiated with the sub beams Sb1 and Sb2 is smaller, the DRC signal is positive. Becomes Normally, the irradiation position of the main beam Mb and the irradiation positions of the sub beams Sb1 and Sb2 are positions shifted from each other by half a track groove. Therefore, when the main beam Mb is on the track groove Tr (on-track), the sub beams Sb1 and Sb1
b2 is located between the track groove Tr and the track groove adjacent to the track groove Tr (off-track). Conversely, when the main beam Mb is off-track, the sub-beams Sb1 and Sb2 are on-track. In an optical disc, the on-track reflectivity is smaller than the off-track reflectivity, so that the off-track / on-track of the main beam Mb can be determined from the positive / negative of the DRC signal.

On the other hand, the adder 51 adds and outputs the output signals A, B, C and D of the main beam photodiode 41, and the sample and hold circuit 52 samples and holds the B value from the output.

FIG. 6 is a diagram for explaining the sample hold. FIG. 6A shows an output waveform of the adder 51. The sample hold circuit 52 performs sampling after a lapse of a certain period from the beginning of the waveform, for example, 5T, in a long pit of the output waveform, for example, a pit having a time width of 6T or more, to obtain the B at the trailing end of the waveform. The value is sampled and held (FIG. 6 (b)).

FIG. 7 is a diagram for explaining detection of a stain such as a fingerprint by the DRC signal. In FIG. 7 (a), 3
Reference numeral 01 denotes an optical disk, which represents a cross section of the optical disk 301. Reference numeral 302 denotes an objective lens,
The focus of the laser light applied to the light source 01 is controlled. X
Is a stain such as a fingerprint attached to the optical disc 301.

FIG. 7B shows a DRC signal, and the DRC signal greatly fluctuates at a position where there is a stain X such as a fingerprint. Dirt such as fingerprints is usually not optically uniform,
The reflected light amount of the main beam and the reflected light amount of the sub beam are
It fluctuates greatly due to the dirt. Therefore, the DRC signal which is a relative value between the reflected light amount of the main beam and the reflected light amount of the sub beam fluctuates randomly as shown in FIG. 7 (b).

The window comparator 71 is connected to the DR
Detect the fluctuation of the C signal. Since the DRC signal slightly fluctuates due to irregularities in the reflectance of the optical disc and noise generated by an electric circuit, a predetermined threshold is set in advance, and when the DRC signal exceeds the threshold, the DRC comparator signal (FIG. 7C) ) Is output.

The one-shot multivibrator 72
A signal of a predetermined pulse or less is removed from the DRC compare signal, and a fingerprint detection signal is output (FIG. 7 (d)).
For example, the linear velocity for tracing an optical disk is 1.2 m /
s, assuming that the size of the stain to be detected is 1 mm, the time required to pass through the stain is 0.83 ms.
Remove pulses less than s.

The ROPC loop filter 83 receives the fingerprint detection signal, and when the fingerprint detection signal is Lo, the control characteristics are set to a low speed and a narrow band, and when the fingerprint detection signal is Hi, the control characteristics are set to a high speed and a wide band. A correction value is calculated and output from the difference between the output at 105 and the B value target value.

The adder 32 adds the above correction value to the target recording power value and outputs the result. WAPC loop filter 34
Receives the difference between the output of the adder 32 and the output of the monitoring photodiode 102, sets the recording current, and outputs it. The semiconductor laser diode 101 emits a first laser beam based on the recording current.

The recording current correction circuit 84 directly corrects the recording current by outputting the recording current to be increased to the adder 35 when the output of the subtracter 33 exceeds the control frequency band limit of the WAPC loop filter. Do. The semiconductor laser diode 101 emits a laser beam based on the recording current.

As described above, according to the recording power correction apparatus 100 of the first embodiment, the B value of the reflected light and the DR value are determined based on the electric signal indicating the intensity of the reflected light from the write-once optical disc.
C, and when a stain such as a fingerprint is detected based on the DRC signal, the ROPC loop filter 83
The recording power of the semiconductor laser diode 101 is corrected by setting the control characteristics of the laser diode to high speed and wide band, and to low speed and narrow band when not detected. To
Since the control is performed so as to follow dirt such as a fingerprint attached to the recording surface and not to follow the deviation of the recording surface, the data recording state on the optical disk can always be optimized.

[0055]

According to the recording power correction apparatus of the present invention (claim 1), the intensity of forming pits on an optical disk on which data is recorded based on the presence or absence of pits formed on the track groove based on the recording data. A first laser beam of
A recording power correction device used in an optical disc apparatus having a laser beam irradiating means for recording the recording data on the optical disc by irradiating it with a second laser beam having an intensity that does not form pits. Light receiving means for receiving reflected light of the first or second laser light and outputting a reflected light intensity signal representing the intensity of the reflected light;
Pit reflected light detection means for outputting a first signal representing the reflected light intensity at the rear end of the pit based on the reflected light intensity signal of the first laser light; and based on the reflected light intensity signal of the second laser light. A track detecting means for outputting a second signal indicating whether or not the laser beam is irradiated on a track groove of the optical disc; and a track detecting means for outputting the track of the optical disc when the second signal is equal to or more than a predetermined threshold value. A fingerprint detecting means for outputting a third signal indicating that a fingerprint or dirt is present on the groove; and a change in the first signal due to the fingerprint or dirt when the third signal indicates that the fingerprint or dirt is present. And control means for outputting a control signal for controlling the irradiation intensity of the first laser light, so that the intensity of the laser light irradiated when data is recorded on the optical disc can be determined by the fingerprint attached to the recording surface. Etc. It follows the les, and the recording surface vibration, etc. can be controlled to not follow, can be a data recording state on the optical disc always optimal.

Further, according to the present invention (claim 2), in the recording power correction apparatus according to claim 1, the control means, when the third signal indicates that there is a fingerprint or stain, Since the control signal is output at a higher speed and a wider band than the predetermined control characteristic, the control signal is output, so that the intensity of the laser beam irradiated at the time of recording data on the optical disk follows the stain such as a fingerprint attached to the recording surface. ,And,
Since the control can be performed without following the recording surface deviation or the like, the data recording state on the optical disk can always be optimized.

According to the present invention (claim 3), in the recording power correction apparatus according to claim 1, the control signal directly corrects a current value flowing to the laser beam irradiation means. Since the current flowing in the laser beam irradiated when recording data on the optical disk can be corrected at a high speed without following dirt such as fingerprints attached to the recording surface and without following the recording surface deviation, etc. Therefore, the data recording state on the optical disk can always be optimized.

Further, according to the present invention (claim 4), in the recording power correction apparatus according to any one of claims 1 to 3, the laser beam irradiating means includes a second laser beam on a track groove of the optical disk. A first light emitting element for irradiating
A second light emitting element for irradiating a second laser beam between the track grooves of the optical disc, wherein the light receiving means receives the reflected light of the optical disc generated by the first light emitting element and reflects the reflected light intensity; A first light receiving element for outputting a light intensity signal, and a second light receiving element for receiving reflected light of the optical disk generated by the second light emitting element and outputting a reflected light intensity signal representing the light intensity; The track detecting means includes:
The second signal is output based on the reflected light intensity signal output from the light receiving element and the reflected light intensity signal output from the second light receiving element. A fingerprint or the like can be detected with high sensitivity and high accuracy without being affected, and the data recording state on the optical disk can always be optimized.

Further, according to the present invention (claim 5), in the recording power correction device according to any one of claims 1 to 4, the laser beam irradiation means receives the second laser beam and receives the second laser beam. A light receiving element for monitoring that outputs a light intensity signal representing the light intensity, and a control circuit that receives the light intensity signal and controls the irradiation intensity of the second laser light, and keeps the irradiation intensity of the second laser light constant Therefore, the state of recording data on the optical disk can be always kept stable.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a recording power correction device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a DRC circuit 106 and peripheral circuits thereof.

FIG. 3 is a block diagram illustrating a configuration of a fingerprint detection circuit 107;

FIG. 4 is a block diagram showing a configuration of an APC circuit 103 and a ROPC loop filter circuit 108.

FIG. 5 is a diagram for explaining details of a sample hold.

FIG. 6 is a diagram illustrating a sample hold.

FIG. 7 is a diagram for explaining detection of a stain such as a fingerprint by a DRC signal.

8 is a block diagram showing a detailed configuration of the recording power correction device of FIG.

FIG. 9 is a diagram for explaining the relationship between laser light and reflected light applied to a write-once optical disc.

FIG. 10 is a block diagram for explaining a conventional recording power correction device.

FIG. 11 is a diagram for explaining a B value, recording power, and a reproduction RF signal envelope when a control band of ROPC is narrow.

FIG. 12 is a diagram for explaining a B value, recording power, and an RF signal envelope when the control band of ROPC is wide.

[Explanation of symbols]

11, 81: Recording power target value storage circuit 12, 15c, 17, 19, 22c, 32, 35, 62
a to f, 51: adder 13: recording power setting limiter 14, 22, 33, 82, 63a to e: subtractor 15a, 15b, 22a, 22b: multiplier 15d, 22d: unit delay unit 16: recording current reference Value storage circuit 18: Recording current setting limiter 100: Recording power correction device 101: Semiconductor laser diode 102: Monitor photodiode 103: APC circuit 104: Servo / RF photodiode 105: B value detection circuit 106: DRC detection circuit 107 : Fingerprint detection circuit 108: ROPC loop filter circuit 111: digital APC circuit 112: digital ROPC loop filter circuit 21, 81: B value target value storage circuit 23: recording current correction circuit 200: recording power correction device 201: semiconductor laser diode 202 : Photoda for monitor Ide 203: APC circuit 204: Photodiode for servo / RF 205: B value detection circuit 206: ROPC loop filter 31: Recording power target value storage circuit 34: WAPC loop filter 301: Optical disc 302: Objective lens 41: Photo for main beam Diodes 42, 43: photodiodes for sub-beams 61a to 61f, 52: sample and hold circuits 64, 65: amplifier circuits 71: window comparators 72: one-shot multivibrators 83: ROPC loop filters 84: recording current correction circuits

Claims (5)

[Claims] 1. A first laser beam having an intensity of forming a pit and a second laser having an intensity of not forming a pit are formed on an optical disk on which data is recorded based on the presence or absence of a pit formed on a track groove, based on recording data. A recording power correction device used in an optical disk device having a laser light irradiating means for recording the recording data on the optical disk by irradiating the optical disk with the laser light, wherein the first or second laser light generated by the optical disk is A light-receiving means for receiving the reflected light and outputting a reflected light intensity signal representing the intensity of the reflected light; and a first means for representing the reflected light intensity at the rear end of the pit based on the reflected light intensity signal of the first laser light. Pit reflected light detecting means for outputting a signal of the second laser light, and determining whether or not the laser light is irradiated on the track groove of the optical disc based on the reflected light intensity signal of the second laser light. A track detection means for outputting a second signal indicating the presence of a fingerprint or a stain on a track groove of the optical disk when the second signal is equal to or more than a predetermined threshold value; Detecting means for controlling the irradiation intensity of the first laser beam by following a change in the first signal due to the fingerprint or stain when the third signal indicates that there is a fingerprint or stain. And a control means for outputting a control signal. 2. The recording power correcting apparatus according to claim 1, wherein said control means, when said third signal indicates that there is a fingerprint or dirt, makes the control characteristic faster than a predetermined control characteristic. A recording power correction device for outputting the control signal as a wide band. 3. The recording power correction apparatus according to claim 1, wherein the control signal directly corrects a current value flowing through the laser beam irradiation means. 4. The recording power correction device according to claim 1, wherein the laser light irradiating means irradiates a second laser beam onto a track groove of the optical disk, and the optical disk. And a second light emitting element for irradiating a second laser beam between the track grooves of the optical disc. The light receiving means receives the reflected light of the optical disk generated by the first light emitting element and reflects the light intensity. A first light-receiving element for outputting an intensity signal; and a second light-receiving element for receiving reflected light of the optical disk generated by the second light-emitting element and outputting a reflected light intensity signal representing the light intensity. The track detecting means outputs the second signal based on a reflected light intensity signal output from the first light receiving element and a reflected light intensity signal output from the second light receiving element. Recording power Correction device. 5. The recording power correction apparatus according to claim 1, wherein said laser beam irradiation means receives a second laser beam and outputs a light intensity signal representing the light intensity. A light receiving element; and a control circuit for receiving the light intensity signal and controlling the irradiation intensity of the second laser light, wherein the control circuit keeps the irradiation intensity of the second laser light constant. Recording power correction device.