JP2000235712A - Power calibration device of light beam source for recording - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the use of power calibration area of a CD-WO in a CD-WO recorder for proofreading the optimum recording laser power of a laser diode of an optical pickup prior to the data recording to the CD-WO. SOLUTION: The 1st process for executing the test recording of a test signal on the power calibration area of the CD-WO 11 as usual while changing over the laser diode to plural different recording laser powers with respect to the instruction to the start of recording or to the first standby of recording while the CD-WO 11 is held in the set state to a tray, and the 2nd process for reading out the test signal in the last test recording from the power calibration area of the CD-WO 11 in succession to the 1st process and proofreading the optimum recording laser power by a reproduced signal obtained from the read-out, are carried out in this device. For the instruction to the start of recording or to the standby of recording after the 2nd times, however, the 1st process is appropriately obviated and the 2nd process only is carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a CD-WO (C
D-Write at Once)
The present invention relates to a power calibration device for calibrating an optimum recording power of a recording light source when recording data using a light beam from a recording light source such as a laser diode.

[0002]

2. Description of the Related Art Using light from a laser diode, C
When recording data on the D-WO, the quality of the recording is determined by the CD-
Prior to recording, a test signal is recorded in the power calibration area of the CD-WO while switching the laser diode to a plurality of different recording powers, and the recorded test is performed. The optimum recording laser power is calculated from the reproduced signal obtained by reading the signal. Since the capacity of the power calibration area of the CD-WO is limited, if recording and stopping are repeated frequently, the power calibration area for recording the test signal runs out, and the CD-WO has:
Even though there is still data remaining, data cannot be recorded.

In Japanese Patent Application Laid-Open No. 5-144061, the identification code of the CD-WO and the optimum recording laser power calculated by the last power calibration are stored in a memory in association with each other, and the stored optimum recording laser power is stored. The use of the power calibration area is suppressed by using.

[0004]

Problems to be Solved by the Invention
In the power calibrating apparatus disclosed in Japanese Patent Application Laid-Open No. 1-2003, an identification code and the latest optimum recording laser power for each CD-WO need to be stored in the memory.

An object of the present invention is to provide a power calibration apparatus for a recording light source that can suppress the use of a power calibration area of an optical disk without storing the latest optimum recording laser power in a memory.

[0006]

According to the power calibration device (10) for a recording light source of the present invention, the first instruction to start recording or to wait for recording on the optical disk (11) being set in the optical disk setting unit is provided. Then, the test signal is test-recorded in the power calibration area of the optical disk (11) while switching the recording light source to a plurality of different recording powers, and the recording light beam is obtained from the reproduction signal obtained by reading the test-recorded test signal. Calculate the optimal recording power of the source. In response to the second or subsequent instruction to start recording or wait for recording on the optical disk (11) being set in the optical disk setting section, unconditionally or under predetermined conditions, test the power calibration area of the optical disk (11). The test recording of the signal is omitted, and only the test signal that has already been recorded as the test record during the current setting is read in the power calibration area of the optical disc (11), and the recording signal is obtained from the reproduction signal obtained from the reading. The optimum recording laser power of the light source is calculated.

The optical disk (11) has at least a CD-W
O (11) is included. The optical disk (11) having the power calibration area is also called a write-once optical disk. The optical disc (11) is not limited to one that records audio data, but also includes one that records video data. When recording data on the optical disk (11), the user may immediately issue a recording start instruction, or may issue a recording standby instruction (usually by operating a pause key) first, and then issue a recording start instruction. There is. The recording light source is usually a laser diode. In addition, the user may issue a recording release instruction without issuing a recording start instruction even after issuing a recording standby instruction. To issue a recording standby instruction first, and then issue a recording start instruction,
In response to the next recording start instruction, data recording on the optical disk (11) is performed using the optimum recording power detected at the time of the first recording standby instruction without performing new test recording or test signal reading. Is performed.

[0008] The predetermined condition means that the optimum recording power of the recording light source is obtained from a reproduction signal obtained by reading a test signal which has already been recorded as a test record in the power calibration area of the optical disk (11). Is calculated based on whether or not the calculated optimum recording power has a predetermined reliability. For example, when the recording start or recording standby instruction is issued within a predetermined time from the test recording time, or when the current recording start or recording standby instruction is performed, the temperature of the recording light source at the time of the test recording is changed. On the other hand, if the difference is within a predetermined range, the reproduced signal of the test signal that has already been test-recorded has sufficient reliability.

On the other hand, when the predetermined condition is not satisfied, the recording light source is set to a plurality of different recording powers in the same manner as the first instruction to start recording or wait for recording on the optical disk (11) being set in the optical disk setting section. The test signal is test-recorded in the power calibration area of the optical disk (11) while switching to the above, and the optimum recording power of the recording light source is calculated from the reproduction signal obtained by reading the test-recorded test signal.

[0010] If the instruction is the second or subsequent instruction to start recording or wait for recording on the optical disk (11) held in the optical disk setting section such as a tray, the optical disk (1)
The test recording of the test signal in the power calibration area of 1) is appropriately omitted, and the test signal already recorded in the power calibration area of the optical disc (11) as the test recording in this set is used, Since only the reading is performed and the optimum recording laser power of the recording light source is calculated from the reproduced signal obtained from the reading, use of the power calibration area is suppressed, and the use of the power calibration area is suppressed. The number of times of additional writing can be increased. In addition, in this recording light source, in order to omit the test recording of the test signal in the power calibration area, it is necessary to store the identification code of the optical disc (11) in the memory in association with the latest optimum recording power. Absent. That is,
Instead of adding a dedicated memory, the power calibration area of the optical disk (11) is used as a memory in order to store the identification code of the optical disk (11) in correspondence with the latest optimum recording power.

According to the power calibrating device (10) for a recording light source of the present invention, the test signal already test-recorded in the power calibration area of the optical disc (11) as the test record during the current set is: This is a test signal recorded in the power calibration area of the optical disc (11) as the last test record during the current set.

According to the power calibrating device (10) of the recording light source of the present invention, the predetermined condition is defined as the condition at the time of the last test recording during the current setting to the power calibration area of the optical disc (11). The first temperature is the temperature of the recording light source, and the second temperature is the temperature of the recording light source at the time of instructing the subsequent recording start or recording standby.
And the second temperature is less than a predetermined value.

The temperature of the recording light source includes not only the temperature of the recording light source itself but also the ambient temperature of the recording light source closely related thereto. The second temperature is not always higher than the first temperature. This is because, even if the optical disk (11) is held in the set state in the optical disk setting section, the power of the recording device (10) may be turned off during the course, and the temperature of the recording light source may be lowered. . First and second
Is the value obtained by subtracting the smaller value from the larger of the first and second temperatures.

The recording power of the recording light source is related to the wavelength of the recording light from the recording light source, and the wavelength of the recording light depends on the temperature of the recording light source. Therefore, if the difference between the first and second temperatures is large, the reliability of the optimum recording power obtained from the reproduction signal obtained from the test signal last recorded in the power calibration area of the optical disk (11) is reduced. . On the other hand, when the difference between the first and second temperatures is small, the optimum recording power obtained from the reproduction signal obtained from the test signal last test-recorded in the power calibration area of the optical disk (11). , Predetermined reliability can be secured.

According to the power calibration device (10) for a recording light source of the present invention, the predetermined condition is that the time of the last test recording during the current setting in the power calibration area of the optical disk (11). At the first time, and in the subsequent recording start or recording standby instruction, the instruction time is the second time, and the time interval between the first and second times is less than a predetermined value.

The recording power of the recording light source changes over time. Accordingly, if the time interval from the first time to the second time is large, the optimum recording power obtained from the reproduction signal obtained from the test signal last test-recorded in the power calibration area of the optical disk (11) is obtained. , The reliability decreases. On the other hand, when the time interval is small, it is considered that the change affecting the recording power of the recording light source is small, and the change is obtained from the test signal last test-recorded in the power calibration area of the optical disk (11). A predetermined reliability can be ensured for the optimum recording power obtained from the reproduced signal.

According to the recording light source power calibration device (10) of the present invention, the temperature of the recording light source at the time of each test recording during the current setting to the power calibration area of the optical disk (11) is determined. The recording temperature is stored as a test recording temperature, and when the current recording start or recording standby instruction is given, the temperature of the recording light source at the time of the instruction is detected as the current temperature, and the difference from the current temperature is within a predetermined value and the current temperature The optimum recording power of the recording light source is calculated from a reproduction signal obtained by reading a test signal at the test recording temperature closest to the above from the power calibration area of the optical disk (11).

While the optical disk (11) is maintained in the set state in the optical disk setting section, the temperature of the recording light source fluctuates depending on the use state. This fluctuation may be reduced by power-off of the recording device (10) of the optical disk (11). In addition, during the limited period in which the optical disk (11) is held in the set state in the optical disk setting section, the recording power of the recording light source is less affected by factors other than the temperature of the recording light source. Is determined.
Therefore, if there is a test record performed at a temperature that is within a predetermined value and is closest to the current temperature, the optimum recording power obtained from the reproduction signal obtained from the test signal in that test record is the same as the optimum recording power for the current write. It is considered that sufficient reliability is secured. Thus, not only the last test recording temperature but also the previous test temperature is compared with the current temperature, and the difference between the current temperature and the test temperature is within a predetermined value and the test signal is read at the test recording temperature closest to the current temperature. By obtaining the optimum recording power based on the reproduction signal from the CPU, it is possible to further save the power calibration area.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a recording light source. CD-WO11 as write-once optical disc
After being mounted on a predetermined tray (not shown) as an optical disk setting section for data writing, it is chucked and rotated by the spindle motor 12. A laser diode (not shown) as a recording light source is built in the optical pickup 13 and has a CD-
The recording laser beam can be freely emitted to WO11.
The optical pickup 13 is driven by a CD-W
An electric signal generated by the optical pickup 13, which can be displaced in the emission direction of O 11, from the reflected light with respect to the irradiation of the light beam to the CD-WO 11 at the time of reproduction is input to the error amplifier 20, and Error signals such as a focus error signal and a tracking error signal are extracted, and these error signals are sent to the servo 15. The servo
15, spindle motor based on those error signals
A control signal is sent to the optical pickup 13, the optical pickup 13, and the sled motor 14 to control the rotation speed of the spindle motor 12, the focus of the optical pickup 13, and the position of the optical pickup 13 in the radiation direction of the CD-WO 11. The user must enter the key 23
Is operated to issue an instruction such as recording start, recording standby, and recording cancellation. This instruction is input to the microcomputer 22. The timer 24 is controlled by the microcomputer 22 to measure the elapsed time. The temperature sensor 25 detects the ambient temperature of the laser diode in the optical pickup 13.

Next, an outline of the power calibration will be described with reference to FIG. FIG. 2 shows the time change t of the recording laser power of the laser diode in the first process during power calibration and the time change t of the optimum recording laser power determination value β in the second process in association with each other. Such a recording power setting method is called a so-called Orange Book Part III (Orange Book P).
art III) is defined as a so-called power calibration. This power calibration is
As shown in FIG. 2A, the PCA (Pow
er Calibration Area (power calibration area), the recording laser power Po of the laser diode is set to 1 ATIP (Absolute T).
imInPregroove) a first process of performing test recording by changing each step corresponding to a frame, and a peak value Al and a bottom value A2 of an RF signal which is a reproduction signal obtained by reading out the test-recorded test signal by the optical pickup 13. And the optimum recording laser power determination value β =
(Al + A2) / (Al-A2) is calculated, and β
And the second step of setting the recording laser power when が becomes a predetermined value to the optimum recording laser power.

FIG. 2 shows the value of β in correspondence with the recording laser power of each level of the laser diode in time, and the value of β corresponding to an increase in the level of the recording laser power of the laser diode. Is also increasing. This CD
In the WO recorder 10, the recording laser power of the laser diode when β becomes a predetermined value is set as the optimum recording laser power. There are various methods for determining the optimum recording laser power. 5-1440
No. 61, a DC component is removed from an EFM / RF signal as a reproduced signal obtained by reading a test signal,
Note that the recording laser power that makes the amplitude center of only the AC component of the M-RF signal substantially zero may be determined as the optimum recording laser power. As shown in FIG. 2A, the recording power at the time of the test recording is switched in a stepwise manner, so that there is a case where there is no recording laser power in which β just becomes a predetermined value. In such a case, the optimum recording power is calculated with an accuracy of about 0.1 mW by interpolation using a method such as linear approximation.

The normal capacity of the power calibration area in the CD-WO 11 is usually 100 power calibrations. In a general CD-WO recorder, a test signal is recorded in the power calibration area of the CD-WO 11 each time the user issues a recording standby instruction as well as a recording start instruction. The recording start instruction is not issued finally and the CD
-The test recording of the test signal in the power calibration area of WO11 may be meaninglessly ended. And C
In a write-once optical disc such as D-WO11, the remaining amount of the power calibration area is used up earlier than the remaining amount of data recording, and data may not be recorded. The CD-WO recorder 10 handles this.

The user operates the timer 24 to issue a recording start or recording standby instruction. When the recording start or recording standby instruction is the first instruction while holding the CD-WO 11 in the set state on the tray, the first step is performed, and subsequently, the second step is performed. Will be implemented. That is, in the first process, the microcomputer 22
(Laser Diode) FIG. 2 shows the recording laser power of the laser diode in the optical pickup 13 via the drive 27.
The test signal is recorded in the power calibration area of the CD-WO 11 by switching as shown in FIG. In the second step, the test signal recorded in the last range of the power calibration area of the CD-WO 11, that is, the test signal recorded in the first step, is read by the optical pickup 13 and reproduced. An RF signal as a signal is output from the optical pickup 13. This RF signal is R
After being amplified by the F-amplifier 19, it is input to the decoder / encoder 21 as a reproduced EFM signal, and is also input to the heak bottom detector 26, where the peak value A1 and the bottom value A2 are output.
Is detected. The peak value A1 and the bottom value A2 are input to the microcomputer 22, the β value is calculated in the microcomputer 22, and the recording laser power of the laser diode at which β becomes a predetermined value is determined. Set the optimum recording laser power. Then, with the start of data recording, the microcomputer 22 adjusts the optimum recording laser power of the laser diode of the optical pickup 13 to the newly set one this time via the LD drive 27, and
The light beam of the laser diode is converted to CD-WO11
And irradiates the data recording area, and data is recorded there. When the user issues a data recording cancel instruction via the key 23, the CD-WO 11 is stopped.

Thereafter, when the user again issues an instruction to start recording or wait for recording from the key 23, the first step is omitted,
Only the second step is performed. That is, the test signal recorded at each recording laser power is read from the last test recording portion of the power calibration area of the CD-WO 11, and the heak bottom detector 26 detects A1, A2 from the reproduced EFM signal from the RF amplifier 19. The microcomputer 22 detects
Β is calculated based on A1 and A2. With the start of recording, the recording laser power of the laser diode corresponding to the preset value β is set to the optimum recording laser power, and the recording laser power of the optical pickup 13 is set to the optimum recording laser power via the LD drive 27. Together, CD-
Data recording to WO11 is started. Thus, CD-W
The use of the power calibration area of O11 can be saved.

In any case, when the tray is opened by a key input from the key 23, the CD-WO 11 may be exchanged. The instruction is executed without omitting the first step, and the recording laser power of the laser diode is calculated.

The recording laser power of the laser diode of the optical pickup 13 changes depending on the temperature of the laser diode and the passage of time. Therefore, even if the CD-WO 11 is kept in the set state on the tray continuously, a large temperature change of the laser diode or a large time If there has been a progress, the first step can be skipped without skipping the first step.
And the second step are performed to calibrate the optimum recording laser power of the laser diode. Specifically,
The ambient temperature of the laser diode is appropriately detected by the temperature sensor 25, and the elapsed time can be measured by the timer 24. Then, when the test signal of the recording laser power is test-recorded by executing the first process (not necessarily when the first instruction of the recording start or the recording standby is issued).
The temperature sensor 25 detects the detected temperature A1 at that time, resets the timer 24, and starts measuring the elapsed time T from that time. When a recording start or recording standby instruction is issued, the detected temperature A2 of the temperature sensor 25 and the elapsed time T at that time are obtained. The absolute value of the difference between A2 and A1 is a predetermined value A
When it is not less than p (| A2−A1 | ≧ Ap) or when the elapsed time T is not less than the predetermined value Tp (T ≧ Tp), the first and second steps are omitted without omitting the first process. Both steps are performed to calibrate the optimum recording laser power of the laser diode.

[Brief description of the drawings]

FIG. 1 is a block diagram of a recording light source.

FIG. 2 is a diagram showing a time change t of a recording laser power of a laser diode in a first process in power calibration and a time change t of an optimum recording laser power determination value β in a second process in association with each other. .

[Explanation of symbols]

 10 CD-WO recorder (light source for recording) 11 CD-WO (optical disc)

Claims (5)

[Claims] The first instruction to start recording or to wait for recording on an optical disk (11) being set in an optical disk setting unit,
A test signal is test-recorded in the power calibration area of the optical disk (11) while switching the recording light source to a plurality of different recording powers, and the recording light source is obtained from a reproduction signal obtained by reading the test-recorded test signal. The optimum recording power of the optical disk (11) is set unconditionally or under a predetermined condition in response to the second or subsequent instruction to start recording or wait for recording on the optical disk (11) being set in the optical disk setting section. The test recording of the test signal in the power calibration area of) is omitted, and only the reading of the test signal already recorded as the test recording in the power calibration area of the optical disc (11) as the test recording during this setting is performed. A recording light source for calculating an optimum recording laser power of a recording light source from a reproduction signal obtained from reading; Power calibration apparatus of the source. 2. A test signal which has already been recorded as a test record in the power calibration area of the optical disk (11) during the current set is the last test signal in the power calibration area of the optical disk (11) during the current set. 2. The recording light source according to claim 1, wherein the test signal is a test signal recorded as a test record. 3. The predetermined condition is that the temperature of the recording light source at the time of the last test recording during the current setting to the power calibration area of the optical disk (11) is a first temperature, and 3. A recording apparatus according to claim 2, wherein a difference between the first and second temperatures is less than a predetermined value, wherein a temperature of the recording light source at the time of instructing recording start or recording standby is set as a second temperature. Light source power calibration device. 4. The predetermined condition is that the time of the last test recording during the current setting in the power calibration area of the optical disk (11) is set as a first time, and a subsequent recording start or recording standby instruction is issued. , The designated time is set to the second
4. The power calibration apparatus for a recording light source according to claim 2, wherein a time interval between the first time and the second time is less than a predetermined value. 5. The temperature of the recording light source at the time of each test recording during the current setting to the power calibration area of the optical disk (11) is stored as a test recording temperature, and the current recording start or recording is performed. In the standby instruction, the temperature of the recording light source at the time of the instruction is detected as a current temperature, and a test signal at the time of test recording at a test recording temperature whose difference from the current temperature is within a predetermined value and closest to the current temperature is detected. 2. The power calibration device for a recording light source according to claim 1, wherein an optimum recording power of the recording light source is calculated from a reproduction signal obtained by reading from a power calibration area of the optical disk. .