JP4193132B2 - Laser power control apparatus and control program for optical disk apparatus - Google Patents

Description

The present invention is applied to an optical disk apparatus for recording / reproducing information on an optical disk using a laser beam, in particular, in the optical disc apparatus for controlling laser power in APC (Auto Power Control) method, O PC (Optimum Power Calibration) the when running, a laser power control device and a control program for due to that there is a time lag in the control of the laser power to prevent defective optimum power setting function is produced.

2. Description of the Related Art Conventionally, in an optical disc apparatus, when performing an information recording / reproducing operation by irradiating an optical disc, which is an information recording medium, with a laser beam from a laser diode, which is a light source, there has been a laser power control method called an APC method. It is used a lot.
This APC system suppresses fluctuations in laser power caused by temperature changes and the like, and always maintains a constant optimum laser power in the recording / reproducing mode.

The APC laser power control apparatus generally has a circuit configuration as shown in FIG.
First, laser light of a laser diode (LD) 2 that is driven by a laser diode drive circuit (hereinafter referred to as “LD drive circuit”) 1 and emits light is irradiated onto an optical disc 4 via an optical system such as a beam splitter 3. The reflected light is guided by a beam splitter 3 to a photodiode (PD) 5 that is a photodetector, and the beam power of the laser diode 2 is detected as a current value.
The detected current of the photodiode 5 is converted into a voltage value by a current / voltage conversion circuit (hereinafter referred to as “I / V conversion circuit”) 6, and a high-frequency component of the voltage is removed by a low-pass filter (LPF) 7. After the average value, sampling is performed by a sample hold circuit (hereinafter referred to as “S / H circuit”) 8, and the sampling value is converted into digital data by an AD conversion circuit 9.

The digital data of the voltage average value is output to the comparison circuit 10 as an optical power monitor value. The comparison circuit 10 compares a predetermined target value with the optical power monitor value and outputs the difference to the compensation circuit 11 at the next stage. To do.
The compensation circuit 11 compensates the phase of the difference value input from the comparison circuit 10 to generate control data Dapc for the LD drive circuit 1, and outputs the data to the DA conversion circuit 12.
The LD drive circuit 1 controls the output power of the laser diode 2 based on the control signal after conversion by the DA conversion circuit 12, but the control data Dapc is generated as data for converging the difference value to zero. The optical power monitor value quickly converges to the target value by the operation of the feedback loop, and the output power of the laser diode 2 is controlled to a level corresponding to the target value.

The power target value is a value that gives the optimum beam power in the recording / reproducing mode, and is selectively switched by a recording / reproducing switching signal. (Generally, a higher level value is set in the recording mode than in the reproduction mode.)
In the recording mode, the LD drive circuit 1 blinks the laser diode 2 based on the ON / OFF signal corresponding to the modulation signal from the modulation circuit 13.

As for the laser power control system, many proposals have been made from various viewpoints as seen in the following patent documents.
JP-A-6-309686 JP-A-8-288580 JP 9-219044 A Japanese Patent Laid-Open No. 11-134692

By the way, in the laser power control circuit, there is a slight time lag between the output of the photodiode 5 being AD converted and the DA conversion via the comparison circuit 10 and the compensation circuit 11.
Further, when the sampling frequency in the S / H circuit 8 is low, the time lag further increases.
As a result, when the recording / reproducing mode is switched, the feedback loop does not function normally, and as shown in FIG. 15, the light emission power of the laser diode 2 becomes unstable and changes in a spike shape for a certain period immediately after switching. There are cases.
This phenomenon not only lowers the recording / reproduction quality immediately after switching the recording / reproduction mode, but also affects the servo function of the optical pickup, and in extreme cases, servo control may be disabled. .

In the APC type optical disc apparatus, OPC is often executed in a test area or the like provided in advance on the optical disc 4 in order to obtain the optimum recording power (target value in the recording mode).
In this case, the measurement is performed by switching the power target value for each power recording block of a specific length in the test area or the like, but if there is the time lag, the power setting value is switched by the OPC block switching signal as shown in FIG. There is a possibility that normal measurement data cannot be obtained because an unstable period is interposed in a certain period immediately after.

Accordingly, the present invention, even the time lag is present, O PC laser diode when switching the recording block can be stably emission in a highly accurate OPC prior to eliminate the Kitoi problem points always It was created for the purpose of providing a laser power control device and a control program for realizing the function.

According to a first aspect of the present invention, there is provided an optical disc apparatus for recording / reproducing information on / from an optical disc using a laser beam, a light detecting means for detecting a light emission amount of a laser light source as a current value, and the detected current value as a voltage value Current / voltage conversion means for conversion, AD conversion means for converting the voltage value into digital data to obtain a laser power monitor value, comparing the laser power monitor value with a preset target value, and a difference value thereof A feedback loop comprising: a comparing means for obtaining control data; a control data generating means for generating control data using the difference value as error information; and a laser light source control means for controlling the light emission amount of the laser light source based on the control data. In the recording mode and the playback mode, the target values are switched to the recording mode target value and the playback mode target value, respectively. In the laser power control device for controlling the light emission quantity of the laser light source in the laser, when the measurement mode for obtaining the optimum laser power for recording is set, the feedback control stop means for stopping the laser power control by the feedback loop And data holding means for storing a plurality of control data for obtaining the optimum laser power, and based on the setting of the measurement mode, each control data is sequentially read from the data holding means to the laser light source control means, Recording execution means for recording information on the optical disc in a control state of the light emission amount of the laser light source by data, and start when the recording execution means starts recording in the control state by the control data Timing control to stop the operation of AD conversion means for a certain period from the time And monitor value holding means for storing each laser power monitor value output by the AD conversion means after the predetermined period when recording is performed for each control data by the recording execution means, and the monitor value holding means is stored. An optical disc apparatus comprising: target value setting means for analyzing each laser power monitor value to determine an optimum laser power value for recording and setting it as a target value for a recording mode in the feedback loop The present invention relates to a laser power control apparatus.

The present invention is applied when the OPC operation is performed in the laser power control apparatus for an optical disc apparatus having the APC function.
In the present invention, when the measurement mode (OPC mode) is set, the laser power control by the feedback loop is stopped by the feedback control stop means.
Then, each control data of the data holding unit is sequentially read out, and the recording execution unit executes recording on the optical disc in a state where the light emission amount of the laser light source is controlled by each control data. At that time, the timing control unit performs each recording. The operation of the AD conversion means is stopped for a certain period from the start time.
Therefore, each laser power monitor value stored in the monitor value holding means is the one after the predetermined period, and even when there is an unstable period of the emission power of the laser diode when each control data is switched, the laser power monitor in that period The value is not stored, and the target value setting means can obtain the optimum laser power based on the data of the stable period after the period, and the target value setting accuracy can be improved.
Incidentally, before Symbol length of the "predetermined period" according to the characteristics of the feedback loop or laser diode, it is desirable to be able to freely variably set for timing control means.

The second invention comprises a first and said comparison means in the invention and the control data generating means and said feedback control stop unit and the data holding means and the recording execution means and said timing control means the monitoring value holding means A program for causing a computer to execute each function of the target value setting means, wherein the laser power monitor value obtained by the AD conversion means is compared with a preset target value to obtain a difference value thereof. And the setting state of the recording / reproducing mode, control data is generated using the difference value obtained in the first procedure as error information, and the control data is output to the laser light source control means for recording. When the measurement mode for obtaining the optimum laser power is set, the second procedure for stopping the output of the control data and the optimum laser power Based on the third procedure for storing a plurality of control data for obtaining the first storage means in the first storage means and the setting of the measurement mode, each control data stored in the third procedure is sequentially controlled by the laser light source control Read out to the means, and a fourth procedure for executing recording of information on the optical disc in a control state of the light emission amount of the laser light source by each control data, and recording in a control state by each control data in the fourth procedure is started. When the recording is performed for each control data in the fourth procedure and the fifth procedure for stopping the operation of the AD conversion unit for a certain period from the start time, the AD conversion unit performs the certain period. A sixth procedure for storing each laser power monitor value to be output later in the second storage means, and analyzing each laser power monitor value stored in the sixth procedure to obtain an optimum recording level. Seeking Zapawa, according to it to the laser power control program in the optical disk apparatus characterized by performing a seventh step of setting a target value for a recording mode in the feedback loop.

Each of the above-described inventions has the following effects due to the above configuration.
According to the first aspect of the present invention, in the optical disc apparatus that executes the APC operation and also performs the OPC operation, when the information is recorded by sequentially switching the light emission power of the laser light source in the OPC mode, the light emission power is reduced as described above. Although the stabilization occurs, a target value for obtaining the optimum laser power is set based on each laser power monitor value obtained after the unstable period at the time of each switching. Therefore, a highly accurate APC operation with an accurate target value Is realized.

Also, the second invention, each of the first comparison means and the control data generating means and the recording execution unit feedback control stopping means and the data holding means and the timing control means and monitoring value holding means and the target value setting means in the invention When the function is executed by a computer, a suitable program is provided.

Embodiments of the “laser power control apparatus and its control program in an optical disk apparatus” according to the present invention will be described below in detail with reference to FIGS.
In each of the embodiments, in the feedback loop of the laser power control circuit shown in FIG. 14, recording is performed due to the time lag until the optical power monitor value is obtained from the detection current of the photodiode 5 and the LD driving circuit 1 is controlled. / To deal with the problem that the laser power becomes unstable when switching the playback mode or when switching the recording block at the time of OPC execution, the control data is replaced during the unstable period, and the delay period is added to the operation of the AD converter circuit. The problem is solved by the method of installation.

This embodiment relates to an apparatus for controlling laser power when the recording / reproducing mode is switched in an optical disk apparatus, and its circuit configuration is shown in FIG.
As is clear from comparison between FIG. 14 and FIG. 14, this embodiment also performs APC control, and the basic circuit configuration is common to the control circuit of FIG.
That is, in this embodiment, a switching circuit 21 is provided between the compensation circuit 11 and the DA converter circuit 12, and a pulse generation circuit 22 is provided for the compensation circuit 11 and the switching circuit 21. Other circuit parts are the same as those in FIG.
Therefore, the description of the parts common to FIG. 14 will be omitted here, and the control operation by the switching circuit 21 and the pulse generation circuit 22 which are characteristic parts of this embodiment will be mainly described.

First, an APC setting signal and a recording / reproduction switching signal are input to the pulse generation circuit 22, and an APC enable signal is output from the circuit 22 to the compensation circuit 11 and the switching circuit 21.
Further, the “APC OFF period setting value” can be input to the pulse generation circuit 22.
Then, as shown in the signal timing chart of FIG. 2, the pulse generation circuit 22 detects that the recording / reproduction switching signal is at the “1” level (reproduction mode) when the APC setting signal is “1”. ) And “0” level (recording mode) when switching from one to the other, the APC enable signal is inverted and output only for a certain period.
In other words, the APC enable signal normally outputs “1” level, but every time the recording / reproduction switching signal is switched, it is “0” only for the period set by the “APC OFF period setting value”. Inverted to level.

The compensation circuit 11 operates in a state where the APC enable signal is at the “1” level. During the APC operation, the compensation circuit 11 compensates the phase of the difference value obtained from the comparison circuit 10 and outputs the control data Dapc to the switching circuit 21. In the state of “0” level, it is regarded as an APC OFF instruction and becomes inoperative, and “0” level or predetermined level data is output as invalid data.
On the other hand, two types of switching control data Dsw and Dsr are input to the switching circuit 21 from the outside. When the APC enable signal is at the “1” level, the control data Dapc obtained from the compensation circuit 11 is converted to the DA conversion circuit 12. On the other hand, when the APC enable signal is at "0" level, the switching control data Dsw or Dsr is selectively output to the DA converter circuit 12 according to the recording / reproducing mode setting state.
Here, the switching control data Dsw and Dsr are data for setting the laser power at the time of switching to the recording mode and the reproducing mode, respectively, and are obtained in the stable period after the lapse of the optical power unstable period in FIG. This is data for controlling the LD drive circuit 1 so that power substantially equal to the recording and reproducing laser power can be obtained.
In other words, the control data can obtain an optical power monitor value equivalent to the target value during the APC operation.

Therefore, as shown in FIG. 2, when the recording mode and the reproduction mode are alternately set for the optical disc apparatus, the APC enable signal is set to the “APC OFF period setting” based on the inversion of the recording / reproduction switching signal. Inversion is performed from the “1” level to the “0” level for the predetermined period set by “value”, and the inversion period is set as the APC OFF period.
During that period, the compensation circuit 11 only outputs the invalid data to the switching circuit 21 without outputting the control data Dapc in the APC operation, and the switching circuit 21 switches from the reproduction mode to the recording mode. The switching control data Dsw is output to the DA conversion circuit 12 at the time of switching, and conversely, the switching control data Dsr is output to the DA conversion circuit 12 at the time of switching from the recording mode to the reproduction mode. Then, the laser power of the laser diode 2 is set.
The target values used in the APC operation are for the recording mode and the reproduction mode. These target values are also switched in advance in accordance with the recording / reproduction switching signal within the period. That is, when switching to the recording mode, the value is input to the comparison circuit 10 after switching to the target value for the recording mode, and when switching to the reproduction mode, the value is switched to the target value for the reproduction mode.

  On the other hand, when the period ends, the APC enable signal returns to the “1” level, so that the normal APC operation state is restored and the compensation circuit 11 outputs the control data Dapc. The control data Dapc is output to the DA converter circuit 12 to control the LD drive circuit 1.

As a result, when the recording / reproducing mode is switched, the period during which the laser power becomes unstable is controlled not by the control data Dapc in the APC operation but by the switching control data Dsw or Dsr, and the period ends. After that, the APC operation by the feedback loop is restored, and the control with the control data Dapc is performed. At that time, the laser power is already at a level close to the target value in the normal APC operation. As shown in FIG. 5, stable laser power can be obtained over the entire period in each of the recording mode and the reproduction mode.
That is, the light emission power instability period in FIG. 15 is replaced with the laser power close to the target value, and the occurrence of spike-like power changes can be prevented, and the pull-in operation can be performed almost instantaneously when returning to the APC operation. Complete.
Since it is impossible to prevent fluctuations in laser power due to temperature changes during the APC OFF period, it is desirable to set the length of the APC OFF period to a range in which the influence of the fluctuation does not appear.

This embodiment relates to a control device for solving the problem that the laser power becomes unstable and does not operate normally when OPC is executed in the optical disc apparatus, and its circuit configuration is shown in FIG.
As is clear from comparison of FIG. 14 and FIG. 14, the basic circuit configuration in this embodiment is also common to the control circuit of FIG.
In other words, in this embodiment, a data holding circuit 31, a data selection circuit 32, a power monitor value holding circuit 33, and a timing signal generation circuit 34 are provided as circuits for executing OPC. The circuit configuration is the same as that of FIG. 14 except that the circuit 32 is provided between the compensation circuit 11 and the DA conversion circuit 12.
Therefore, also in this embodiment, the description of the parts common to FIG. 14 will be omitted, and the control operation of each of the circuits 31 to 34 mainly related to OPC will be described.

First, the OPC block switching signal, the recording / reproducing switching signal, and the OPC mode signal are input to the data holding circuit 31, the data selection circuit 32, and the timing signal generation circuit.
The data holding circuit 31 holds a plurality of externally input OPC data (OPC control data) Dopc (i) [i = 1 to m] and the OPC mode signal is “1” (OPC mode ON). , Detection of the rising edge of the recording / playback switching signal from “0” to “1” (that is, switching from the playback mode to the recording mode), and each synchronization with the OPC block switching signal output as a trigger pulse thereafter. The OPC data Dopc (i) is sequentially output to the data selection circuit 32.
Each OPC data Dopc (i) is control data for sequentially changing the light emission power of the laser diode 2 to different levels by the LD drive circuit 1.
The data selection circuit 32 outputs the control data Dapc of the compensation circuit 11 based on the APC operation to the DA converter circuit 12 when the OPC mode signal is “0” (OPC mode OFF), but the OPC mode is ON as described above. In the state, each OPC data Dopc (i) input from the data holding circuit 31 is output to the DA converter circuit 12.

A signal timing chart in the OPC mode setting state is shown in FIG. 4, and the circuit operation will be described below with reference to FIG.
As described above, when each OPC data Dopc (i) is output to the DA converter circuit 12, the LD drive circuit 1 is controlled by the control signal after DA conversion, and the light emission power of the laser diode 2 is changed to each OPC data Dopc (i). In the OPC mode, a predetermined modulation signal is input from the modulation circuit 13 to the LD drive circuit 1, and light emission of the laser diode 2 is blinked at each level to record information. .
Then, in the light emission power control state by each OPC data Dopc (i), the sampling value obtained by processing the detected current of the photodiode 5 by the I / V conversion circuit 6, the low-pass filter 7, and the S / H circuit 8 is AD. The conversion circuit 9 converts it into digital data C (i) to obtain an optical power monitor value in each control state.
Then, after each optical power monitor value corresponding to each OPC data Dopc (i) is saved in the power monitor value holding circuit 33, the system control unit 40 analyzes the optical power monitor value to obtain an optimum power, The optimum power is output to the comparison circuit 10 as a target value for APC.

By the way, in the conventional OPC execution procedure, when the OPC mode is in the ON state, the optical power monitor value is immediately obtained from the time when the playback mode is switched to the recording mode and the trigger pulse of the subsequent OPC block switching signal is detected. The power monitor value holding circuit 33 was saved.
However, in this embodiment, the timing signal generation circuit 34 outputs a data acquisition signal to the AD conversion circuit 9 at a predetermined timing, thereby limiting the data acquisition period of the AD conversion circuit 9.
That is, as shown in FIG. 4, when there is a rising edge of the recording / reproducing switching signal and a trigger pulse of the OPC block switching signal inputted thereafter, the timing signal generating circuit 34 generates constant data after the rising edge or pulse input. A data capture signal is output with a capture delay period interposed.
This data capture signal is output as a pulse having a predetermined width. However, when a single pulse is output to one OPC block as in the data capture signal a in FIG. In the case where the data captured in is used as the optical power monitor value for the OPC block at that time and is output as a plurality of pulses for one OPC block as in the data capture signal b, each pulse width The average value of each optical power monitor value captured during the period is taken as the optical power monitor value for the OPC block.

Here, when the light emission power of the laser diode 2 is changed to a different level by the OPC block switching signal, the data acquisition delay period is not constant during a certain period immediately after the switching as shown in FIG. In consideration of stabilization, the delay period is set longer than the unstable period.
However, if the data acquisition delay period is made too long, the data acquisition period in the OPC block is shortened. Therefore, in each OPC block, the pulse of the data acquisition signal can be output with sufficient margin in the remaining period excluding the data acquisition delay period. Stay in range.
If the period set value can be input from the outside to the timing signal generation circuit 34, the data acquisition delay period can be adjusted according to the feedback loop of the APC and the characteristics of the laser diode 2.

As described above, the timing signal generation circuit 34 controls the data capture period of the AD conversion circuit 9, but the OPC mode is ON and the OPC input after the rise of the recording / reproduction switching signal is in the ON state. In synchronization with the trigger pulse of the block switching signal, the storage address Add (i) for saving the optical power monitor value corresponding to each OPC block is output to the power monitor value holding circuit 33, and is obtained in each OPC block. The obtained optical power monitor values are sequentially saved in the power monitor value holding circuit 33 in a divided manner.
Therefore, the power monitor value holding circuit 33 has an optical power monitor at a stable level immediately after switching from the reproduction mode to the recording mode and after an unstable period of light emission power immediately after the OPC block switching signal is output. The value is saved, and the system control unit 40 can analyze the data to obtain an accurate optimum recording power, and can set a target value for the recording mode with no error for the comparison circuit 10.
As a result, the optical disc apparatus can execute an APC operation in which the target value is set with high accuracy according to the characteristics of the laser diode 2 and the LD drive circuit 1, and can increase the setting accuracy of the optimum laser power applied in the recording mode to record information. Reliability can be improved.

In the first embodiment (circuit configuration shown in FIG. 1), the laser power is controlled when the recording / reproducing mode is switched by the hardware configuration. In this embodiment, the main control portion is a microcomputer circuit ( In the following, it is replaced with “microcomputer circuit” to execute control in software.
The circuit configuration of the laser power control apparatus of this embodiment is shown in FIG.
As is apparent from comparison between FIG. 1 and FIG. 1, in the apparatus of this embodiment, the comparison circuit 10, the compensation circuit 11, the switching circuit 21, and the pulse generation circuit 22 in FIG. However, the other circuit portions are the same as in FIG.
Here, the microcomputer circuit 50 has a general circuit configuration including a CPU 51, a ROM 52, a RAM 53, an I / O port 54, and a timer 51a, and functions of the circuits 10, 11, 21, and 22 shown in FIG. The operation procedure is stored in the ROM 52 as a program.
And when CPU51 runs the program, control similar to the apparatus of Example 1 is performed.

Hereinafter, the laser power control procedure by the apparatus of this embodiment will be described with reference to the flowchart of FIG.
First, the following various setting values are input from the I / O port 54.
That is, the setting value corresponding to the gain or the like input to the compensation circuit 11 in the first embodiment, the setting value corresponding to the APC OFF period input to the pulse generation circuit 22, and the switching control input to the switching circuit 21. Each data corresponding to the data Dsw and Dsr and a set value for the recording mode and the reproducing mode corresponding to the target value input to the comparison circuit 10 are input, and each is stored in a predetermined area of the RAM 53 in advance ( S1-S4). The input order of the set values and data is not particularly limited.

When the above inputs are completed, the APC setting signal input to the I / O port 54 is turned on to enter the APC operation state, the laser diode 2 is set to ON, and then the recording mode or reproducing mode is set by the recording / reproducing switching signal. Is set (S5 to S7).
Here, assuming that the recording mode has been set first, the CPU 51 switches off the APC operation based on the detection of the recording mode setting signal, and two types of switching control data Dsw and Dsr stored in the RAM 53. The control data Dsw on the recording mode is output to the DA conversion circuit 12 via the I / O port 54, and the timer 51a starts counting (S8, S9).
As the recording mode is set, preparations for the APC operation are made in advance by setting a flag corresponding to the recording mode target value in each target value of the APC operation stored in the RAM 53. (S10).

Therefore, immediately after the recording mode is set, the control data Dsw is output to the DA conversion circuit 12 via the I / O port 54, and the LD drive circuit 1 drives the laser diode 2 with the light emission power based on the control data Dsw. Then, it is blinked by the modulation signal input from the modulation circuit 13.
Here, the control data Dsw is set as data for controlling the LD driving circuit 1 so as to obtain a power substantially equal to the recording laser power obtained in the stable period after the lapse of the optical power instability period in FIG. Therefore, information recording with the light emission power is performed.

By the way, the CPU 51 monitors the count value of the timer 51a, and when the count value is in the OFF period of the APC stored in the RAM 53, the APC operation that is OFF is switched ON (S11, S12).
Then, the CPU 51 compares the optical power monitor value obtained from the AD conversion circuit 9 with the recording mode setting value previously prepared in step S10, and uses the value obtained by phase compensation of the difference value as a result of the comparison as the APC control data Dapc. The data is output from the I / O port 54 to the DA conversion circuit 12.
Therefore, if the recording mode is set, recording in the APC operation state is continuously executed as it is (S12).
The timer 51a stops counting when the APC OFF period ends (S13).

Next, when the recording / reproduction switching signal input to the I / O port 54 is switched to the reproduction mode, the CPU 51 that detects it switches the APC operation to OFF, and at the reproduction mode side stored in the RAM 53. The control data Dsr is output to the DA converter circuit 12 via the I / O port 54, and the timer 51a starts counting (S14 to S16).
As the playback mode is set, preparation for the APC operation is made in advance by setting a flag corresponding to the playback mode target value in the RAM 53, as in the recording mode (step S10). (S17).

Therefore, immediately after the reproduction mode is set, the control data Dsr is output to the DA conversion circuit 12 via the I / O port 54, and the LD drive circuit 1 drives the laser diode 2 with the light emission power based on the control data Dsr. Thus, reproduction is executed with the light emission power.
Here, the control data Dsr is set as data for controlling the LD drive circuit 1 so as to obtain a power substantially equal to the reproducing laser power obtained in the stable period after the lapse of the optical power unstable period in FIG. Thus, information reproduction is performed with the light emission power.

As in the recording mode, the CPU 51 monitors the count value of the timer 51a in the playback mode, and when the count value is in the OFF period of the APC stored in the RAM 53, the APC operation is switched ON (S19).
Thereafter, the optical power monitor value obtained from the AD conversion circuit 9 is compared with the reproduction mode target value previously prepared in step S17, and a value obtained by phase compensation of the difference value obtained by the comparison is used as APC control data Dapc as I / O The output from the port 54 to the DA converter circuit 12 is the same as in the recording mode except that the target value is different (S18, S19).
Also, the count operation of the timer 51a is stopped when the APC OFF period ends, as in the recording mode (S20).

Thereafter, each time the recording / reproducing mode is switched by the recording / reproducing switching signal as described above, the APC operation is once set to OFF, and the control data Dsw and Dsr are converted into the DA conversion circuit according to each mode for the APC OFF period. 12 and the APC operation is returned to ON after the period has elapsed (S20 → S7 to S13 → S14 to S20).
Therefore, also in the apparatus of this embodiment, the same functions and effects as those of the control apparatus of Embodiment 1 can be obtained.

The laser power control apparatus of this embodiment is to execute the function of the apparatus (hardware configuration) of the embodiment 2 in software, and in that sense, is similar to the relationship of the apparatus of the embodiment 3 to the apparatus of the embodiment 1. It is.
The circuit configuration of the laser power control apparatus of this embodiment is shown in FIG.
As is apparent from a comparison between FIG. 3 and FIG. 3, in the apparatus of this embodiment, the comparison circuit 10, the compensation circuit 11, the data holding circuit 31, the data selection circuit 32, the power monitor value holding circuit 33 in FIG. The timing signal generation circuit 34 is composed of the microcomputer circuit 60, but the other circuit portions are the same as in the case of FIG.
Here, the microcomputer circuit 60 has a general circuit configuration including a CPU 61, a ROM 62, a RAM 63, an I / O port 64, and a timer 61a, and the circuits 10, 11, 31, 32, 33, and 34 shown in FIG. The operation procedure related to the function is stored in the ROM 62 as a program.
The CPU 61 executes the program to perform the same control as that of the apparatus of the second embodiment.

The laser power control procedure by the apparatus of this embodiment will be described below with reference to the flowchart of FIG.
First, the following various setting values are input from the I / O port 64.
That is, in the second embodiment, the setting value corresponding to the gain or the like input to the compensation circuit 11 and the setting value corresponding to the data acquisition delay period input to the timing signal generation circuit 34 are input, and the predetermined value of the RAM 63 is input in advance. Store in the area (S31, S32).
Further, after the APC setting signal is turned ON to set the APC operation state and the laser diode 2 is turned ON, the OPC data D (i) [i = 1 to m] is input and the data is stored in the RAM 63 (S33 to S33). S35).
In this embodiment, the OPC data D (i) [i = 1 to m] is input at the above stage, but it may be stored in the ROM 62 in advance as fixed data.

When the procedure is completed, the OPC mode signal of the I / O port 64 is used to switch to the OPC mode, and the APC setting signal is switched OFF to turn off the APC operation (S36, S37).
At this stage, a data take-in prohibition signal is output to the AD conversion circuit 9 so that the AD conversion circuit 9 does not take in the sampling data of the S / H circuit 8 (S38).
Then, the CPU 61 reads out the OPC data Dopc (1) relating to the first recording block to the DA converter 12 and starts counting of the timer 61a at the same time, and then records it on the test area of the optical disc 4 by the recording / reproduction switching signal. Is started (S39 to S41).
That is, recording is performed while the laser diode 2 is blinked by the modulation signal from the modulation circuit 13 in the laser power setting state controlled by the OPC data Dopc (1).

In that case, in the conventional OPC operation, the optical power monitor value of the AD conversion circuit 9 based on the detection current obtained from the photodiode 5 is immediately taken. In this embodiment, the laser power setting by the OPC data Dopc (1) is performed. In this state, the timer 61a starts counting, and the data acquisition prohibited state of the AD conversion circuit 9 is maintained until the count value counts the data acquisition delay period stored in the RAM 63 (S39). ~ S42).
Therefore, even if recording is started as described above, the AD conversion circuit 9 does not output the optical power monitor value during the data capture delay period.

On the other hand, when the timer 61a counts the data take-in delay period, the CPU 61 outputs a data take-in signal to the AD conversion circuit 9, cancels the data take-in prohibition state, and starts an AD conversion operation (S43).
In this case, the CPU 61 outputs a data fetch signal as a single pulse or a plurality of pulses having a predetermined width, and designates a write address Add (1) to the RAM 63 in synchronization with the pulse output.
As a result, the optical power monitor value C (1) output from the AD conversion circuit 9 is saved to the designated address Add (1) of the RAM 63 via the I / O port 64, and the optical power monitor corresponding to the pulse output period. The value is recorded in the RAM 63 (S44).
When the saving of the optical power monitor value is completed, since the pulse is not output, the AD conversion circuit 9 is in a data import prohibited state (S45).
Further, the CPU 61 stops the count of the timer 61a at this time (S46).

Next, when an OPC block switching signal is input to the I / O port 64, the CPU 61 reads out the OPC data Dopc (2) relating to the next recording block and outputs it from the I / O port 64 to the DA converter 12. The timer 61a starts counting (S47 to S50).
In this case, since the laser diode 2 has already been blinked by the modulation signal from the modulation circuit 13, recording on the test area of the optical disc 4 is automatically performed.
Thereafter, when the timer 61a counts the data acquisition delay period, the data acquisition signal is output as a pulse to the AD converter 9 to start the data acquisition in the same manner as in the steps S42 to S46. After saving the value C (2) to the designated address Add (2) of the RAM 63, the AD conversion circuit 9 is in a data take-in prohibition state and the count of the timer 61a is stopped (S51 to S55).

The steps S48 to S56 are repeatedly executed every time there is a block switching signal for the third and subsequent recording blocks, and when the processing up to the final mth recording block is completed, the OPC mode signal is turned OFF, The OPC operation is completed (S56, S57 → S48 to S56 / S56 → S58).
As a result, the optical power monitor values C (1) to C (C (1) to C (()) in the laser power setting state controlled by the respective OPC data Dopc (1) to Dopc (m) are stored in the addresses Add (1) to Add (m) of the RAM 63. m) has been recorded.

Therefore, the CPU 61 transfers each OPC data Dopc (1) to Dopc (m) and each optical power monitor value C (1) to C (m) to the system control unit (not shown) via the I / O port 64. Then, the system control unit analyzes the data to obtain the optimum power, and returns the optical power monitor value corresponding to the optimum power to the microcomputer circuit 60 (S59).
The microcomputer circuit 60 stores the optical power monitor value related to the optimum power in the RAM 63 as a target value for the recording mode in APC, and the target value is applied in the recording mode in the subsequent APC operation (S59).
Therefore, also in the apparatus of this embodiment, the same functions and effects as those of the control apparatus of Embodiment 2 can be obtained.
In the above description, the system control unit obtains the optimum power. However, an analysis program is prepared in the ROM 62 of the microcomputer circuit 60, and the CPU 61 obtains the optimum power based on the data recorded in the RAM 63 to obtain the APC. The target value may be set directly.

As in the case of the first embodiment, this embodiment relates to a device for controlling the laser power when the recording / reproducing mode is switched in the optical disk apparatus, and its circuit configuration is shown in FIG.
As is apparent from a comparison between FIG. 1 and FIG. 1 (circuit configuration of the first embodiment), this embodiment also performs APC control, and the basic circuit configuration is the same as that of the control circuit of FIG. is doing.
That is, the control data generation circuit 20, the AD conversion circuit 23, the memory 24, and the temperature sensor 25 are newly added as circuit elements to the circuit of FIG. 1, but the other circuit portions are as shown in FIG. It is almost the same as the case.
In the circuit of this embodiment, input of an APC target value to the comparison circuit 10, input of a setting value such as a gain to the compensation circuit 11, input of an APC setting signal and an APC OFF period setting value to the pulse generation circuit 22 are performed by system control. The recording / reproduction switching signal is output from the system control unit 40 ′ to the pulse generation circuit 22 and the control data generation circuit 20, and the APC enable signal of the pulse generation circuit 22 is supplied from the switching circuit 21. Not only that, it is also input to the control data generation circuit 20.
Therefore, the description of the parts common to FIG. 1 is omitted here, and the control operation by the additional circuit elements, which is the feature of this embodiment, will be mainly described.

First, the AD conversion circuit 23 converts the LD drive voltage output from the LD drive circuit 1 into digital data, and outputs the digital data to the control data generation circuit 20 as an LD drive voltage monitor value.
The temperature sensor 25 detects the temperature of the laser diode 2 itself or a temperature in the vicinity thereof, and outputs the detected temperature data to the control data generation circuit 20.
The memory 24 stores in advance control voltage-laser power characteristics under a large number of temperature conditions as a temperature characteristic table, and is also used as a data save area by the control data generation circuit 20 to monitor the LD drive voltage monitor. Values and temperature data are saved as appropriate.

The feature of this embodiment is that the control data generation circuit 20 has an APC enable signal from the pulse generation circuit 22, a recording / reproduction switching signal from the system control unit 40 ', output data from the compensation circuit 11, and an AD conversion circuit. The LD drive voltage monitor value from 23 and the temperature data from the temperature sensor 25 are input, respectively, and when the control data generation circuit 20 switches from the reproduction mode to the recording mode, the final value of Dapc in the previous recording mode. Is output to the switching circuit 21 as switching control data Dsw ′. When switching from the recording mode to the reproduction mode, the switching control data Dsr ′ corrected using the temperature characteristic table of the memory 24 is obtained and output to the switching circuit 21. In the point.
The switching circuit 21 outputs the control data Dapc obtained from the compensation circuit 11 to the DA converter 12 during the APC ON period when the APC enable signal is “1”, and the APC OFF period when the APC enable signal is “0”. Then, the control data generation circuit 20 outputs the switching control data Dsw ′ and Dsr ′ generated according to the recording mode and the reproduction mode to the DA converter 12, and the LD driving circuit 1 outputs the control data Dapc, Dsw ′, Dsr. The laser power of the laser diode 2 is set based on the control signal after DA conversion.

Hereinafter, a method of generating the switching control data Dsw ′ and Dsr ′ will be described with reference to FIG.
(1) Generation of Dsw ';
The control data generation circuit 20 updates Dsw ′ = Dapc (control data obtained from the compensation circuit 11) when the recording / reproduction switching signal is “1” (recording mode) and the APC enable signal is “1”. In the other period, the final value of Dapc in the recording mode is continuously held, and in the period in which the recording / reproduction switching signal is “1” and the APC enable signal is “0”, the last Dapc held The value (final value of Dapc in the previous recording mode) is output to the switching circuit 21 as switching control data Dsw ′.
(2) Generation of Dsr ';
The control data generation circuit 20 updates Dsr ′ = Dapc (control data obtained from the compensation circuit 11) when the recording / reproduction switching signal is “0” (reproduction mode) and the APC enable signal is “1”. Subsequently, during the other periods, the final value of Dapc in the reproduction mode is held, and a value obtained by adding the correction value ΔD to the value is obtained as the switching control data Dsr ′, and the recording / reproduction switching signal is “0” ( The switching control data Dsr ′ is output to the switching circuit 21 during the period when the APC enable signal is “0”.

Here, the correction value ΔD relating to the generation of the switching control data Dsr ′ in (2) is obtained by the control data generation circuit 20, and has the following significance.
First, FIG. 11 is a graph showing a drive current-light emission power characteristic of a general laser diode. The light emission power of the laser diode is proportional to the drive current and has a temperature characteristic in which temperature is involved as a parameter. When the same light emission power is obtained, a higher driving current is required if the temperature is increased.
That is, when the laser diode is caused to emit light with high power, a large amount of drive current is consumed and the temperature rises, and accordingly, the drive current-light emission power characteristic shifts to the right as shown in FIG.
Therefore, if the recording mode for emitting light at a high power continues for a certain period of time, the drive current-light emission power characteristics change from the playback mode before the recording mode, and the control data Dapc by APC in the previous playback mode is output. The light emission power may be reduced.
Therefore, the temperature characteristic table of FIG. 11 in which the drive current is replaced with the control data is stored in the temperature characteristic table of the memory 24, and the control data generation circuit 20 stores the LD drive voltage monitor value obtained from the AD conversion circuit 23. The control data conversion value and the temperature data obtained from the temperature sensor 25 are applied to the temperature characteristic table of the memory 24 to obtain the correction value ΔD, and the correction value ΔD is added to the control data Dapc in the APC operation in the previous reproduction mode. The LD drive circuit 1 is controlled by outputting the value (Dapc final value + ΔD) to the switching circuit 21 as switching control data Dsr ′.

The correction value ΔD is obtained by the following procedure.
First, the control data generation circuit 20 takes in the temperature data from the temperature sensor 25 at a constant cycle as shown in FIG.
If the temperature Tmp1 is detected at the time t1 and the temperature rises to Tmp2 at the time t2 when the recording mode continues for a certain time, the control data corresponding to the temperatures Tmp1 and Tmp2 in that case—light emission power The characteristics are indicated by Tmp1 and Tmp2 in FIG.
The control data generation circuit 20 also captures the drive voltage monitor value at time t1 and saves it in the memory 24. The control data generation circuit 20 obtains the conversion value D1 of the monitor value into the control data, and relates the conversion value D1 to Tmp1. The light emission power value Pr is obtained by applying the control data to the light emission power characteristic.
In this case, since the light emission power value Pr is controlled during the APC ON period, the level value is almost the APC target value. However, the control data-light emission power characteristics relating to the level value Pr and Tmp2 To obtain control data D2.
Then, a difference (D2-D1) between the control data D1, D2 obtained based on the temperature characteristic is set as a correction value ΔD.

  That is, a data correction value ΔD (= D2−D1) for compensating for a deficient drive current due to a temperature increase of ΔTmp = Tmp2−Tmp1 is obtained, and the correction value ΔD is set as the Dapc final value in the previous reproduction mode. By giving the switching control data Dsr ′ by the addition, the decrease in the light emission power is compensated.

  When the recording mode or the reproduction mode is first set immediately after the optical disk apparatus is powered on or immediately after the system is reset, the temperature data of the laser diode 3 is detected from the temperature sensor 25 and the temperature in the memory 24 is set. Control data for obtaining a desired light emission power in the recording mode or the reproduction mode may be set as Dsw ′ or Dsr ′ using the corresponding control data-light emission power characteristic.

The laser power control apparatus according to the present embodiment causes the functions of the apparatus (hardware configuration) according to the fifth embodiment to be executed by software. It is the same as the relationship.
The circuit configuration of the laser power control apparatus of this embodiment is shown in FIG.
As is apparent from a comparison between FIG. 9 and FIG. 9, in the apparatus of this embodiment, the comparison circuit 10, the compensation circuit 11, the control data generation circuit 20, the switching circuit 21, the pulse generation circuit 22, and the memory 24 in FIG. This part is constituted by the microcomputer circuit 70, but the other circuit parts are the same as those in FIG.
Here, the microcomputer circuit 70 has a general circuit configuration including a CPU 71, a ROM 72, a RAM 73, an I / O port 74, and a timer 71a, similar to that applied to the apparatus of the third and fourth embodiments. The operation procedure of the functions performed by the circuits 10, 11, 20, 21, 22, 24 is stored in the ROM 72 as a program.
And when CPU71 runs the program, control similar to the apparatus of Example 5 is performed.
Further, the ROM 72 stores a temperature characteristic table relating to control data-light emission power characteristics as shown in FIG. 11 based on data measured at the time of adjustment of the optical disk device or the like.

The laser power control procedure by the apparatus of this embodiment will be described below with reference to the flowchart of FIG.
First, various setting values are input from the I / O port 74.
That is, the setting value corresponding to the gain or the like input to the compensation circuit 11 in the fifth embodiment, the setting value corresponding to the OFF period of APC input to the pulse generation circuit 22, and the target value input to the comparison circuit 10. Corresponding setting values for the recording mode and the reproduction mode are input and stored in predetermined areas of the RAM 73 in advance (S61 to S63). The input order of the set values and data is not particularly limited.

When each input is completed, the temperature data Tmp0 is acquired from the temperature sensor 25, and each LD required to output the light emission power for reproduction and recording at the temperature Tmp0 using the temperature characteristic table of the ROM 72. The control data value is stored in a predetermined area of the RAM 73 as the initial value of the switching control data Dsr ′ and Dsw ′ (S64, S65).
Next, when the APC setting signal input to the I / O port 74 is set to ON and enters the APC operation state (S66), the laser diode 2 is turned on. In order to prevent this, the ON setting is normally made in the reproduction mode (S67).

In the playback mode and when the APC operation is ON, the CPU 71 periodically acquires the temperature data Temp1 from the temperature sensor 25, and then acquires the LD control data D1 at that time and stores it in a predetermined area of the RAM 73. Store while updating (S68).
In this state, when the rising edge of the recording / playback switching signal from “0” to “1” is detected (that is, the switching from the playback mode to the recording mode is detected), the APC operation in the previous playback mode is performed. The final value of the control data Dapc is stored in a predetermined area of the RAM 73 (S69, S70).

The CPU 71 switches off the APC operation by detecting the rising edge of the recording / reproduction switching signal, and controls the recording mode of the two types of switching control data Dsw ′ and Dsr ′ stored in the RAM 73. The data Dsw ′ is output to the DA conversion circuit 12 via the I / O port 74, and the timer 71a starts counting (S71, S72).
As the recording mode is set, preparation for the APC operation is made in advance by setting a flag corresponding to the target value for the recording mode in each target value of the APC operation stored in the RAM 73. (S73).

Therefore, immediately after the recording mode is set, the LD drive circuit 1 drives the laser diode 2 with the light emission power based on the switching control data Dsw ′, and blinks with the modulation signal input from the modulation circuit 13.
Here, the switching control data Dsw ′ is data for controlling the LD drive circuit 1 so that a power substantially equal to the recording laser power obtained in the stable period after the lapse of the optical power instability period in FIG. 15 is obtained. Since it is set, information recording is performed with the light emission power.

Incidentally, the CPU 71 monitors the count value of the timer 71a, and when the count value is in the OFF period of the APC stored in the RAM 73, the APC operation in the OFF state is switched to ON (S74, S75).
Then, the CPU 71 compares the optical power monitor value obtained from the AD conversion circuit 23 with the recording mode target value previously prepared in step S73, and uses the value obtained by phase compensation of the difference value as a result of the comparison as the APC control data Dapc. The data is output from the I / O port 74 to the DA conversion circuit 12.
Therefore, if the recording mode is set, recording in the APC operation state is continuously executed as it is (S75).
The timer 71a stops counting when the APC OFF period ends (S76).

Further, during the recording mode and the period in which the APC operation is set to ON, the CPU 71 periodically acquires the temperature data Tmp2 from the temperature sensor 71a, and then refers to the temperature characteristic table of the ROM 72 to determine the temperature Tmp2 The LD control data D2 required to output the light emission power in the reproduction mode is obtained (S77).
Then, a difference ΔD (= D2−D1) between the LD control data D2 and the LD control data D1 acquired at the time of reproduction is obtained, and the value ΔD is stored in the RAM 73 in step S70 in the reproduction mode APC control data Dapc. The result is added to the final value, and the result is stored in the predetermined area of the RAM 73 as new switching control data Dsr '(S78).

Thereafter, when the CPU 71 detects the falling edge of the recording / reproduction switching signal from “1” to “0” (that is, detects the switching from the recording mode to the reproduction mode), the CPU 71 ends the Dapc in the recording mode. The value is stored in the predetermined area of the RAM 72 as the switching control data Dsw ′, the APC operation is switched to OFF, and the switching control data Dsr ′ for the reproduction mode stored in the RAM 73 is transferred from the I / O port 74 to the DA conversion circuit. 12 and the timer 71a starts counting (S79 to S82).
As the playback mode is set, as in the recording mode (step S73), preparations for the APC operation are made in advance by setting a flag corresponding to the playback mode target value in the RAM 73, for example. (S83).

Therefore, immediately after the reproduction mode is set, the LD drive circuit 1 drives the laser diode 2 with the light emission power based on the switching control data Dsr ′, and information reproduction is performed with the light emission power.
Here, the switching control data Dsr ′ is corrected using the temperature characteristic table of the memory 25 while detecting the temperature data from the temperature sensor 25 as described above, and the temperature of the laser diode 2 during the recording mode time zone. Since the decrease in the light emission power due to the rise in the light can be compensated for, the laser power for reproduction obtained in the stable period after the instability of the optical power in FIG. The appropriate power value is obtained.

Similarly to the recording mode, the CPU 71 also monitors the count value of the timer 71a in the playback mode, and switches the APC operation to ON when the count value is in the APC OFF period stored in the RAM 73 (S84, S84). S85).
Thereafter, the optical power monitor value obtained from the AD conversion circuit 9 is compared with the reproduction mode target value prepared in step S83, and a value obtained by phase compensation of the difference value obtained by the comparison is used as APC control data Dapc as I / O. The output from the port 74 to the DA converter circuit 12 is the same as in the recording mode except that the target value is different (S85).
Further, the count operation of the timer 71a is stopped by the end of the APC OFF period, as in the recording mode (S86).

Thereafter, each time the recording / reproducing mode is switched by the recording / reproducing switching signal as described above, the APC operation is once set to OFF, and the control data Dsw ′ and Dsr ′ are set to DA in accordance with each mode for the APC OFF period. The signal is output to the conversion circuit 12, and the APC operation is returned to ON after the lapse of the period.
Therefore, also in the apparatus of this embodiment, functions and effects similar to those of the control apparatus of Embodiment 5 can be obtained.

  As described above, the present invention is used as an effective control method for the APC function and the OPC function in the optical disc apparatus.

1 is a block circuit diagram of a laser power control device in an optical disc apparatus according to Embodiment 1. FIG. 3 is a signal timing chart for explaining an operation state of the apparatus according to the first embodiment. 6 is a block circuit diagram of a laser power control apparatus in an optical disc apparatus according to Embodiment 2. FIG. 10 is a signal timing chart for explaining an operation state of the apparatus according to the second embodiment. FIG. 6 is a block circuit diagram of a laser power control device in an optical disc device according to a third embodiment. FIG. 10 is a block circuit diagram of a laser power control device in an optical disc apparatus according to Embodiment 4. 12 is a flowchart illustrating an operation procedure of the apparatus according to the third embodiment. 10 is a flowchart illustrating an operation procedure of the apparatus according to the fourth embodiment. FIG. 10 is a block circuit diagram of a laser power control apparatus in an optical disc apparatus according to Embodiment 5. FIG. 10 is a signal timing chart for explaining an operating state of the apparatus according to the fifth embodiment. It is the graph showing the drive current-light-emission power characteristic of a laser diode by making temperature into a parameter. FIG. 10 is a block circuit diagram of a laser power control apparatus in an optical disc apparatus according to Embodiment 6. 12 is a flowchart illustrating an operation procedure of the apparatus according to the sixth embodiment. It is a block circuit diagram of the laser power control apparatus in the conventional optical disk apparatus. It is a signal timing chart which shows the problem at the time of APC execution by the conventional apparatus. It is a signal timing chart which shows the problem at the time of OPC execution by the conventional apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Laser diode drive circuit, 2 ... Laser diode, 3 ... Beam splitter, 4 ... Optical disk, 5 ... Photodiode, 6 ... Current / voltage conversion circuit, 7 ... Low pass filter, 8 ... Sample hold circuit, 9, 23 ... AD Conversion circuit, 10 ... comparison circuit, 11 ... compensation circuit, 12 ... DA conversion circuit, 13 ... modulation circuit, 20 ... control data generation circuit, 21 ... switching circuit, 22 ... pulse generation circuit, 24 ... memory, 25 ... temperature sensor , 31 ... Data holding circuit, 32 ... Data selection circuit, 33 ... Power monitor value holding circuit, 34 ... Timing signal generation circuit, 40, 40 '... System control unit, 50, 60, 70 ... Microcomputer circuit, 51, 61 71, CPU, 51a, 61a, 71a ... Timer, 52, 62, 72 ... ROM, 53, 63, 73 ... RAM, 54, 64, 74 ... I / O port

Claims (2)

In an optical disk apparatus for recording / reproducing information on / from an optical disk using laser light, light detection means for detecting a light emission amount of a laser light source as a current value, and current / voltage conversion for converting the detected current value into a voltage value Means, AD conversion means for converting the voltage value into digital data to obtain a laser power monitor value, comparison means for comparing the laser power monitor value with a preset target value and obtaining a difference value thereof, Provided with a feedback loop composed of control data generating means for generating control data using the difference value as error information, and laser light source control means for controlling the light emission amount of the laser light source based on the control data, and a recording mode and a reproduction mode By switching the target value between the target value for recording mode and the target value for playback mode with In laser power control device for controlling the light emission amount of the laser light source,
Feedback control stop means for stopping laser power control by the feedback loop when a measurement mode for obtaining the optimum laser power for recording is set;
Data holding means for storing a plurality of control data for obtaining the optimum laser power;
Based on the setting of the measurement mode, each control data is sequentially read from the data holding means to the laser light source control means, and information is recorded on the optical disc in a control state of the light emission amount of the laser light source by each control data. Recording execution means for causing
Timing control means for stopping the operation of the AD conversion means for a certain period from the start time when the recording execution means starts recording in the control state by each control data;
Monitor value holding means for storing each laser power monitor value output by the AD conversion means after the predetermined period upon recording for each control data by the recording execution means;
Analyzing each laser power monitor value stored by the monitor value holding means to obtain an optimum laser power value for recording, and setting target value setting means for setting it as a target value for recording mode in the feedback loop A laser power control apparatus for an optical disc apparatus. In the laser power control device in the optical disk device of claim 1 ,
Causes a computer to execute the functions of the comparison means, the control data generation means, the feedback control stop means, the data holding means, the recording execution means, the timing control means, the monitor value holding means, and the target value setting means. A program,
A first procedure for comparing a laser power monitor value obtained by the AD conversion means with a preset target value to obtain a difference value;
In the setting state of the recording / reproducing mode, control data is generated using the difference value obtained in the first procedure as error information, and the control data is output to the laser light source control means, and the optimum laser power for recording is output. When a measurement mode for obtaining the above is set, a second procedure for stopping the output of the control data;
A third procedure for storing a plurality of control data for obtaining the optimum laser power in the first storage means;
Based on the setting of the measurement mode, each control data stored in the third procedure is sequentially read out to the laser light source control means, and information on the optical disc is controlled in a control state of the light emission amount of the laser light source by each control data. A fourth procedure for performing recording;
A fifth procedure for stopping the operation of the AD conversion means for a certain period from the start time when recording is started in a control state by each control data in the fourth procedure;
A sixth procedure for storing each laser power monitor value output by the AD conversion unit after the predetermined period in the second storage unit when recording each control data in the fourth procedure;
Performing a seventh procedure of analyzing each laser power monitor value stored in the sixth procedure to obtain an optimum laser power value for recording and setting it as a target value for a recording mode in the feedback loop; A laser power control program for an optical disc apparatus.

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