JP3246271B2 - Data recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data recording apparatus for recording a data signal on an optical recording medium.

[0002]

2. Description of the Related Art Conventionally, a data recording apparatus for recording a data signal on an optical recording medium can record information by irradiating a disk-shaped recording medium with laser light to sequentially form pits. There is an optical disk device such as a CD compliant with the standard of a so-called compact disk (CD).
-There is an R (CD-Recordable) drive device.

An optical disk used in this CD-R drive device is irradiated with intense laser light, so that the optical properties of a recording layer between pre-grooves, which are guide grooves formed in advance, are changed so that the optical disk is used only once. This is a so-called write-once optical disc on which information can be recorded.

[0004] Specifically, in a CD-R drive device,
EFM (Eight to Fourteen Modulation) for recorded data
, A modulated signal B1 is generated such that the occurrence probabilities of logic 0 and 1 are equal, as shown in FIG. Laser light is emitted from the laser diode based on the modulation signal B1, and the optical disk is intermittently irradiated with laser light corresponding to the logic level of the modulation signal B1. As a result, a region having a low reflectance, that is, a pit, is formed in the recording layer between the pregrooves. At this time, the laser diode is driven with high output.

[0005] The modulation signal B1 is generated such that the H level and the L level are continuous within a period of 3T to 11T with reference to the reference period T. As a result, as shown in FIG. 10B, pits P are sequentially formed and data is recorded. Note that a region where the pits P are not formed and has a high reflectance is called a land.

At the time of data reproduction, a laser diode is driven at a low output to irradiate the emitted laser light onto an optical disk. The reflected light from the optical disk irradiated with the laser light is received by a photodetector. A reproduced signal whose signal level changes as shown in FIG. 10C, that is, an RF signal is obtained according to the amount of the reflected light. Then, by detecting the signal level of the RF signal with reference to the slice level SL, the reproduction data D1 shown in D of FIG. 10 is detected.

At this time, since the modulation signal B1 is generated by the EFM and the occurrence probabilities of the logics 0 and 1 are equal, the slice level SL is selected so that the occurrence probabilities of the logics 0 and 1 are also equal in the reproduced data D1. This allows
The bit error rate is reduced.

On the other hand, at the time of data recording, even if the laser diode is driven with a constant power and emits laser light, the size of the pits changes according to a change in the ambient temperature and a change in the laser wavelength. I do. Therefore, the drive power of the laser diode is sequentially switched, test data is recorded in a test writing area of the optical disk, and the test data is reproduced to detect an asymmetry value Asy at each drive power. This asymmetry value Asy is easily detected using an asymmetry detection circuit. And
The asymmetry value Asy closest to the predetermined asymmetry value Asy is selected from the detected asymmetry values Asy. Thus, the drive power at the time when the selected asymmetry value Asy is obtained is determined as the optimum drive power of the laser diode.

Here, the asymmetry value indicates the ratio of the time average of pits and lands. Specifically, the RF signal reproduced from the optical disk has the waveform shown in FIG.
It is represented by the relationship between the slice level SL at which the occurrence probabilities of logic 0 and 1 are equal to the reproduction data D1 indicated by D of 0, and the peak level and bottom level of the reproduction signal. That is, the asymmetry value Asy is determined by the peak level X ₁ and the bottom level X
₄ and a peak level X ₂ and a bottom level X ₃ of a signal having a pulse width of 3T in period can be expressed by the following equation (1).

[0010]

(Equation 1)

[0011]

In the above-described CD-R drive device, data is binarized from an RF signal when the recording signal is read out, as an asymmetry value of the recording signal written on the optical disk. A value that minimizes the data error rate at the time of equal decoding is selected. The asymmetry value that minimizes the data error rate is determined by the characteristics of the optical system of the CD-R drive device, the emission time of laser light, the characteristics of the optical disk, and the like. For this reason, the target asymmetry value differs depending on the manufacturer or model of the CD-R drive device.

For example, when the target asymmetry value of the CD-R drive device made by Company A is set to 0%, the CD-R made by Company B
The target asymmetry value of the R drive device may be -5%. In this case, data is recorded halfway on the optical disk by a CD-R drive device manufactured by Company A, and thereafter,
When additional recording for recording data following the recorded data is performed by the CD-R drive device manufactured by Company B, the asymmetry value of the RF signal suddenly differs by 5% before and after the additional recording.

Here, the CD drive device and the CD-R drive device change the slice level for binarizing the RF signal according to the asymmetry value of the RF signal during data reproduction. However, the range that can follow the change of the asymmetry value is about several tens Hz.

Therefore, in the CD drive and the CD-R drive, when data is read from the optical disk on which the additional recording has been performed such that the asymmetry value sharply changes as described above, the slice level has the asymmetry before and after the additional recording. Cannot follow the change in value,
An error may occur when the RF signal is binarized.

In view of the above circumstances, the present invention provides a data recording apparatus capable of performing additional recording of data without a sudden change in asymmetry value before and after additional recording of data.

[0016]

According to the present invention, there is provided a data recording apparatus comprising: a laser irradiating means for irradiating a laser beam to an optical recording medium; and a laser irradiating means for receiving a laser beam reflected from the optical recording medium. Photoelectric conversion means for converting the data signal into a signal, first detection means for detecting whether or not the data signal is recorded on the optical recording medium based on the output of the photoelectric conversion means, and output of the photoelectric conversion means Second detecting means for detecting an asymmetry value based on the data signal, and prior to recording the data signal on the optical recording medium,
The first detector detects whether or not the data signal is recorded in an area of the optical recording medium adjacent to the area where the data signal is recorded. Setting an asymmetry value detected by the second detection means based on a data signal reproduced from the adjacent area as a target asymmetry value,
The above-mentioned object is attained by providing control means for setting a predetermined asymmetry value to the target asymmetry value when the data signal is not recorded.

[0017]

In the present invention, when recording a data signal on an optical recording medium, prior to recording the data,
The first detecting means detects whether or not a data signal is recorded in an area of the optical recording medium adjacent to the area where the data signal is recorded. The detecting means detects an asymmetry value based on a data signal reproduced from an area adjacent to the area where the data is recorded, sets the asymmetry value as a target asymmetry value, and records the data signal. Otherwise, by setting a predetermined asymmetry value as the target asymmetry value, data recording is performed so as to have the same asymmetry value as the asymmetry value of the data signal of the data recording area. .

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic configuration of a data recording apparatus according to the present invention.

This data recording device is a data recording device for recording a data signal on an optical disk 7 as an optical recording medium, and includes a laser diode 1 as a laser irradiating means for irradiating the optical disk 7 with a laser beam. ,
Photodetector 9 serving as photoelectric conversion means for receiving the laser beam reflected from optical disk 7 and converting it into an electric signal
An RF detection circuit 45 serving as first detection means for detecting whether a data signal is recorded on the optical disk 7 based on the output of the photodetector 9 and detecting an asymmetry value based on the output of the photodetector 9 And an asymmetry detection circuit 46 serving as a second detection means for performing the above-mentioned data signal recording on the optical disk 7 before recording the data signal on the optical disk 7 by using the RF detection circuit 45 in an area close to the area where the data signal is recorded on the optical disk 7. It is detected whether or not a data signal is recorded. When the data signal is recorded, the asymmetry value detected by the asymmetry detection circuit 46 is determined based on the data signal reproduced from the adjacent area. If a target asymmetry value is set and the data signal is not recorded, a predetermined The Nmetori value are those comprising a CPU24 and a control means for setting to the target asymmetry value.

Here, the recording format of the optical disk 7 used in the data recording apparatus shown in FIG.
This will be described with reference to FIG.

As shown in FIG. 2, the optical disk 7 is provided with a program area PG, and a TOC (Table of Con
A lead-in area LI including the tents is provided, and a lead-out area LO is provided on the outer peripheral side of the program area PG. Further, the lead-in area L
On the inner peripheral side of I, there are provided a program storage area PMA for recording the recording status of the program area PG, and a power control area PCA including a test writing area in which data for adjusting the laser drive power is written. .

Next, the configuration of the data recording apparatus of this embodiment will be described with reference to FIG.

In FIG. 1, a laser beam emitted from a laser diode 1 is collimated by a collimation lens 2 and guided to an objective lens 6 via a grating 3 and a beam splitter 4. Focused on top.

A part of the light beam incident on the beam splitter 4 is split by the beam splitter 4 and is incident on a laser monitor 5. The light beam incident on the laser monitor 5 is photoelectrically converted to obtain a current value according to the light amount. This current value is sent to the monitor head amplifier 30 and converted into a voltage value, and further sent to the automatic power control (APC) circuit 31.

The APC circuit 31 uses a signal from the monitor head amplifier 30 to control the amount of laser light emitted from the laser diode 1 to be constant without being affected by external factors such as temperature. Things. This AP
The control signal from the C circuit 31 is sent to the laser modulation circuit 29. The laser modulation circuit 29 is provided with the APC circuit 31
The laser diode 1 is driven by the laser drive power based on the control signal from the laser diode 1.

The reflected light of the laser beam irradiated on the optical disk 7 is incident on the beam splitter 4 via the objective lens 6. The beam splitter 4 guides the reflected light to the multi-lens 8. The multi-lens 8 includes a cylindrical lens, a condenser lens, and the like, and condenses the reflected light on the photodetector 9.

The output from the photodetector 9 is converted into a voltage value by a head amplifier 10 and output to a matrix circuit 11. In the matrix circuit 11, the tracking error signal TE, the focus error signal FE, and the push-pull signal PP are generated by adding and subtracting the output from the head amplifier 10. The tracking error signal TE and the focus error signal FE are sent to the phase compensation circuits 12 and 13, respectively.

The tracking error signal TE whose phase has been adjusted by the phase compensation circuit 12 is sent to the drive circuit 14. The drive circuit 14 operates the tracking actuator 16 based on the tracking error signal TE from the phase compensation circuit 12. Thus, tracking control of the objective lens 6 with respect to the optical disk 7 is performed.

The focus error signal FE whose phase has been adjusted by the phase compensation circuit 13 is sent to the drive circuit 15. The drive circuit 15 includes the phase compensation circuit 13
The focus actuator 17 is operated based on the focus error signal FE from. Thus, focus control of the objective lens 6 on the optical disk 7 is performed.

The low-frequency component of the tracking error signal TE is sent to a thread phase compensation circuit 32 for phase compensation, and sent to a drive circuit 33. In the drive circuit 33, the position of the sled mechanism 44 is controlled to move by driving the sled motor 34 using the signal from the sled phase compensation circuit 32.

The push-pull signal PP output from the matrix circuit 11 is output to the wobble detection circuit 21. In the wobble detection circuit 21, the optical disk 7
A wobble signal formed in advance along the track is detected, and an ATIP (Absolute Time In Pre-groov
e) Output to the demodulator 22. The ATIP demodulator 22 detects an ATIP and an ATIP read clock signal from the wobble signal. This AT
The IP and ATIP read clock signals are sent to the ATIP decoder 23. In this ATIP decoder 23,
The address information is reproduced using the ATIP and the ATIP read clock signal. This address information is stored in the C
It is supplied to the PU 24.

The wobble signal detected by the wobble detection circuit 21 and the ATIP read clock signal detected by the ATIP demodulator 22 are also output to a spindle servo circuit 25. This spindle servo circuit 2
5 drives the spindle motor 27 via the motor driver 26 using the wobble signal and the ATIP read clock signal. At this time, the spindle servo circuit 25 controls the wobble signal detected by the wobble detection circuit 21 so as to have a constant frequency of 22.05 kHz, or outputs the ATIP read clock signal output from the ATIP modulator 22. 6.35
The control is performed so as to have a constant frequency of kHz.

The RF signal output from the matrix circuit 11 is sent to a binarization circuit 18 where it is binarized and binarized.
It is sent to the PLL circuit 19 as a value signal. This PLL
In the circuit 19, a clock signal is generated from the binary signal, and this clock signal is sent to the decoder circuit 20 together with the binary signal. The decoder circuit 20 decodes the binary signal based on the clock signal.
Thereby, the data signal and the subcode are reproduced.
The reproduced data signal is output from the output terminal 42.
The sub code is sent to the CPU 24.

The clock signal reproduced by the PLL circuit 19 is input to a spindle servo circuit 25 and compared with a reference clock signal. Then, the comparison output is sent to the motor driver 26 as a rotation error signal. The motor driver 26 controls the driving of the spindle motor 27 based on the rotation error signal.

The above operation is performed both when reproducing data from the optical disk 7 and when recording data on the optical disk 7.

When data is recorded on the optical disk 7, the RF detection circuit 45 reproduces data in a predetermined area on the optical disk 7 to reproduce the data on the optical disk 7 based on the RF signal output from the matrix circuit 11. Detects whether data is recorded or not and outputs this detection signal to C
Supply to PU24.

Here, one embodiment of a schematic configuration of the RF detection circuit 45 is shown in FIG.
FIG. 4 shows a timing chart of each signal in FIG.
The operation of the RF detection circuit 45 will be described.

As shown in FIG. 4A, the signal level of an RF signal reproduced from a recording area where data is recorded changes, but the signal level of an RF signal reproduced from an unrecorded area has almost the same level. It is constant. This RF signal
By passing through the high-pass filter (HPF) 55 shown in FIG. 3, the signal becomes a signal as shown in FIG. The output signal from the HPF 55 is input to the comparator 56.

The comparator 56 slices the output signal at a predetermined slice level. This allows
As shown in FIG. 4C, the recording area has a period of 3T to 11T.
In the unrecorded area, the pulse width becomes longer than the period 11T, and an output signal that always becomes "1" is obtained. This output signal is input to the pulse width detection circuit 57.

The pulse width detection circuit 57 outputs
When the pulse width of the digitized signal is shorter than the period 11T, it becomes "1" indicating that the signal is a reproduction signal from the recording area,
When the pulse width of the binarized signal is longer than the period 11T, "0" indicating that the signal is a reproduced signal from an unrecorded area.
Is output. This detection signal is shown in D of FIG.

FIG. 5 is a flowchart of a first embodiment of a data recording operation procedure in the data recording apparatus.
And described below.

First, in step S1, based on a command from a host computer (not shown), a command from an input device or the like connected to the data recording device, or the like,
A data recording position on the optical disk 7, that is, a recording start position and a recording end position are set. Incidentally, for the optical disc 7,
Recording and reproduction of continuous data are performed from the inner circumference to the outer circumference of the optical disc 7.

Then, the process proceeds to step S2, where the optical pickup 40 is moved by a track jump to the head of an area for a predetermined data amount immediately before the data recording position. The size of the region is set to a size sufficient to detect an asymmetry value. However, if this area is large, it takes a long time to detect the asymmetry value. Therefore, it is desirable that the area be as small as possible. In this embodiment, the data is one sub-code frame of the area. The sub-code frame is a frame composed of a synchronization signal, sub-coding, audio data, and parity and having a reference linear velocity of 1/75 second.

At this time, the CPU 24
By transmitting a control signal to the optical disc 3, the thread motor 34 is controlled and the thread mechanism 44 is driven to move the optical pickup 40 in the radial direction of the optical disk 7. Thus, the optical pickup 40 is moved to the subcode frame immediately before the data recording start position on the optical disc 7.

Further, the CPU 24 sends a control signal to the APC circuit 31 so that the laser diode 1 is driven by the laser drive power for reproduction, and the optical pickup 40
Thus, the data of the subcode frame immediately before the recording start position is reproduced.

As a result, the RF signal obtained via the photodetector 9, the head amplifier 10, and the matrix circuit 11 of the optical pickup 40 is converted into an RF signal by the RF detection circuit 45.
Supplied to The RF detection circuit 45 detects whether data is recorded in the subcode frame immediately before the recording start position.

Then, the detection signal from the RF detection circuit 45 is supplied to the CPU 24, so that step S
At 3, it is determined whether or not data is recorded in the subcode frame immediately before the recording start position.

The CPU 24 controls to reproduce data in at least one subcode frame area immediately after the recording end position, and further performs an operation of detecting whether or not data is recorded. Thereby, it is determined whether or not data is recorded in the subcode frame immediately after the recording end position.

If it is determined in step S3 that data is recorded in the sub-code frame immediately before the recording start position or that data is recorded in the sub-code frame immediately after the recording end position, , Step S4
Proceed to.

Here, in the asymmetry detection circuit 46,
In step S2, an asymmetry value is detected from the reproduced RF signal, and this asymmetry value is
4 is output.

Therefore, in this step S4, the CPU 2
4 sets the asymmetry value detected by the asymmetry detection circuit 46 as a target asymmetry value, and stores the asymmetry value in the memory 47.

On the other hand, if it is determined in step S3 that no data is recorded in either the subcode frame immediately before the recording start position or the subcode frame immediately after the recording end position, the process proceeds to step S5. .

In this step S5, a standard asymmetry value which is predetermined and stored in the memory 47 is set as a target asymmetry value, and this asymmetry value is stored in the memory 47.

After the target asymmetry value is set in this way, the OPC (Optimum Power
r Control) operation, that is, a laser driving power calibration operation. Here, the CPU 24 moves the optical pickup 40 to the power control area PCA of the optical disk 7 by controlling the drive circuit 33, and sequentially changes the test data read from the memory 36 while changing the laser drive power. To record.
Then, an asymmetry value is detected from each RF signal obtained by reproducing the test data recorded at each laser drive power. Thereafter, an asymmetry value that is closest to the target asymmetry value set in step S4 or step S5 is selected from the detected asymmetry values.

Then, in step S7, the CPU 2
Step 4 controls the APC circuit 31 so that the laser drive power is used when recording the test data having the asymmetry value selected in step S6, and records data from the recording start position. At the time of this data recording, the switch 35 is switched to the terminal a and connected to the signal input terminal 43, from which data for recording is inputted. The input recording data is encoded by the data encoder 28 via the switch 35 and sent to the laser modulation circuit 29. Laser modulation circuit 2
In 9, data recording is performed by driving the laser diode 1 with a laser drive power based on a control signal from the APC circuit 31.

FIG. 6 is a flow chart of a second embodiment of the data recording operation procedure in the data recording apparatus.
And described below.

First, in step S11, a data recording position, that is, a recording start position and a recording end position are set. The processing in step S11 is similar to the processing in step S1 in FIG. Next, in step S12, it is determined whether or not the disk exchange information is ON. Whether the optical disk 7 has been replaced is determined according to the detection result from the disk detector 37. This disk detector 37 can be constituted by a photocoupler or the like. The disc exchange information is OFF until the optical disc 7 is exchanged, and turns ON when the optical disc 7 is exchanged.

If it is determined in step S12 that the disc exchange information is ON, it means that the target asymmetry value has not been set once since the optical disc 7 was mounted on the data recording apparatus. In this case, the process proceeds to step S13, where data is reproduced from the optical disk 7 and a target asymmetry value is set. This target asymmetry value is stored in the memory 47. The processing in step S13 is performed in steps S2 to S in FIG.
The processing is the same as the processing up to 5.

On the other hand, if it is determined in step S12 that the disk exchange information is OFF, the process proceeds to step S1.
Proceeding to 4, the asymmetry value stored in the memory 47 is set as the target asymmetry value.

Then, the process proceeds to a step S15, where the same OPC operation as the process of the step S6 in FIG. 5 is performed. After this,
In step S16, the APC circuit 31 is controlled so that the laser drive power at the time of recording the test data having the asymmetry value closest to the target asymmetry value is recorded, and data recording is performed from the recording start position. After the data recording is completed, in step S17, the disc exchange information is
FF is set and the data recording operation ends.

Next, a flowchart of a third embodiment of the data recording operation procedure in this data recording apparatus is shown in FIGS. 6, 7 and 8, and will be described below.

In the third embodiment, when data is recorded in both subcode frames immediately before the recording start position and immediately after the recording end position, which are the data recording positions,
A predetermined amount of data is recorded with the laser drive power set based on the asymmetry value detected from the data of the subcode frame immediately before the recording start position, and the data of the subcode frame immediately after the recording end position is sequentially recorded by the predetermined value. Is switched so as to approach the laser driving power set based on the asymmetry value detected from the above, and the data is recorded by the predetermined amount.

First, in step S21, a data recording position, that is, a recording start position and a recording end position are set. The processing in step S21 is similar to the processing in step S1 in FIG. Next, in step S22, the data of the subcode frame immediately before the recording start position is reproduced. Then, in a step S23, it is determined whether or not data is recorded in the subcode frame immediately before the recording start position. This detection is performed based on the output from the RF detection circuit 45.

If it is determined in step S23 that data is recorded, the process proceeds to step S24,
Detection is performed based on data reproduced from the subcode frame immediately before the recording start position, the detected asymmetry value is set as a target asymmetry value at the recording start position, and the asymmetry value is stored in the memory 47.

On the other hand, if it is determined in step S23 that no data has been recorded, the flow advances to step S25 to set the standard asymmetry value stored in the memory 47 as the target asymmetry value at the recording start position. This asymmetry value is stored in the memory 47.

Next, in step S26, the data of the subcode frame immediately after the recording end position is reproduced. Then, in a step S27, it is determined whether or not data is recorded in the subcode frame immediately after the recording end position. This detection is performed based on the output from the RF detection circuit 45.

If it is determined in step S27 that data is recorded, the process proceeds to step S28,
Detection is performed based on data reproduced from the subcode frame immediately after the recording end position, the detected asymmetry value is set as a target asymmetry value at the recording end position, and this value is stored in the memory 47.

On the other hand, if it is determined in step S27 that no data has been recorded, the flow advances to step S29 to set the standard asymmetry value stored in the memory 47 as the target asymmetry value at the recording end position. This value is stored in the memory 47.

Then, the process proceeds to a step S30 to perform an OPC operation.

Here, the OPC operation will be described in detail.

This OPC operation means that the laser diode 1
Is to determine the optimum value of the laser drive power at the time of data recording. The optimum value of the laser drive power is the value of the laser drive power for the laser diode 1 for recording an RF signal having an asymmetry value that minimizes the data error rate during data reproduction.

First, in this OPC operation, the CPU
The optical pickup 40 is moved to the power control area PCA of the optical disk 7 by controlling the spindle motor 27 and the sled mechanism 44 under the control of 24.

Next, under the control of the CPU 24, the switch 35 is switched to the terminal b to connect to the memory 36, and the test data for asymmetry detection stored in the memory 36 is read. This test data is sent to the laser modulation circuit 29 via the data encoder 28. Further, under the control of the CPU 24, the APC circuit 31 is controlled to drive the laser diode 1 with a plurality of different laser driving powers. As a result, test data with a plurality of different laser drive powers is recorded in the power control area PCA of the optical disc 7.

Thereafter, the recorded test data is reproduced, and the RF signal obtained thereby is sent to the asymmetry detection circuit 46. The asymmetry detection circuit 46 detects an asymmetry value at each laser drive power. The CPU 24 detects the asymmetry value closest to the target asymmetry value among the asymmetry values at each laser drive power detected by the asymmetry detection circuit 46, and optimizes the value of the laser drive power when this asymmetry value is obtained. Value. The laser drive power information indicating the value of the laser drive power set as the optimum value is stored in the memory 4
7 and sent to the APC circuit 31. As described above, the OPC operation is performed.

Next, the process proceeds to step S31, where
23 and based on the detection results in step S27,
It is determined whether data is recorded in both the subcode frame immediately before the recording start position and the subcode frame immediately after the recording end position.

If it is determined in step S31 that data has been recorded in both subcode frames, the flow advances to step S32 in FIG.

Here, if the amount of change in the laser drive power of one subcode frame is represented by Δ, this amount of change Δ
Is as follows when the laser drive power at the recording end position is EP, the laser drive power at the recording start position is SP, the frame number at the recording end position is EF, and the frame number at the recording start position is SF. It can be represented by an equation.

[0078]

(Equation 2)

In step S32, the amount of change in laser drive power for each sub-code frame is determined based on the equation (2). The obtained value of the change amount is stored in the memory 47 as change amount data. As a result, the laser drive power can be changed stepwise for each subcode frame.

Then, the flow advances to step S33 to set the target laser drive power at the recording start position. That is, CP
U24 reads the drive power information of the recording start position stored in the memory 47 and outputs a control signal corresponding to the drive power information to the APC circuit 31. This allows
The target laser drive power in the APC circuit 31 is set.

Next, at step S34, the signal input terminal 4
The data for one subcode frame input from 3 is
The data is encoded by the data encoder 28 via the switch 35 and sent to the laser modulation circuit 29, so that data of one subcode frame is recorded on the optical disk 7.

Next, the process proceeds to a step S35, where it is determined whether or not the current position is the recording end position. That is, step S34
To detect whether or not data has been recorded at the recording end position. If it is determined in step S35 that the current position is the recording end position, the processing of the data recording operation ends. If it is determined that the current position is not the recording end position, the target laser drive power is changed by the above-described amount in step S36. That is, the CPU 24 reads the change amount data stored in the memory 47 and controls the target laser drive power of the APC circuit 31 based on the change amount data. Then, the process proceeds to step S34 to record data for one subcode frame. As described above, the processing from step S34 to step S36 is performed until it is determined that the recording end position is reached in step S35.

If it is determined in step S31 that no data is recorded in both the subcode frame immediately before the recording start position and the subcode frame immediately after the recording end position, that is, only one of the subcode frames is recorded. If it is determined that no data is recorded in the sub-code frame, or if data is not recorded in both sub-code frames, the process proceeds to step S37 in FIG.

Then, in step S37, based on the detection results in steps S23 and S27, it is determined whether or not data is recorded only in the subcode frame immediately before the recording start position.

If it is determined in step S37 that data is recorded only in the subcode frame immediately before the recording start position, the process proceeds to step S38, where the target laser obtained from the target asymmetry value at the recording start position is obtained. Record all data with drive power. That is, the CPU 24 reads the drive power information of the recording start position stored in the memory 47, and controls the target laser drive power of the APC circuit 31 based on the drive power information. Then, all data is recorded on the optical disk 7 with the target laser drive power.

In step S37, no data is recorded only in the subcode frame immediately before the recording start position, that is, data is recorded only in the subcode frame immediately after the recording end position, or If it is determined that the sub-code frame immediately before the start position and the sub-code frame immediately after the recording end position are not recorded, the process proceeds to step S39. This step S
At 39, all data is recorded with the target laser drive power obtained from the target asymmetry value at the recording end position. That is, the CPU 24 reads the drive power information of the recording end position stored in the memory 47, and controls the target laser drive power of the APC circuit 31 based on the drive power information. Then, all data is recorded on the optical disk 7 with the target laser drive power.

Here, even when data is not recorded in both the linear subcode frame at the recording start position and the subcode frame immediately after the recording end position, recording is performed with the target laser drive power at the recording end position. However, when the data is not recorded in both subcode frames, the drive power information is stored as the same value in the memory 47 for both the recording start position and the recording end position. This is because there is no problem using information.

Further, in the third embodiment, after the reproduction of the data of the subcode frame immediately before the recording start position and the setting of the target asymmetry value of the recording start position, the operation immediately after the recording end position is performed. Although the sub-code frame is reproduced, the data recording apparatus of the present invention is not limited to this. After reproducing the sub-code frame immediately before the recording start position and immediately after the recording end position, the recording is performed. The target asymmetry value at the start position and the recording end position may be set.

In addition to controlling the asymmetry value by changing the laser driving power of the laser diode 1, the light emission time of the laser beam, that is, a pit of a signal having the same size, for example, a pulse width of 3T period is formed. It is also possible to control by controlling the emission start time and emission end time of the laser light at that time. In this case, C
A control signal is supplied from the PU 24 to the laser modulation circuit 29, and the laser modulation circuit 29 controls the emission time of the laser light.

Further, instead of the asymmetry value detected during the OPC operation, an energy center value can be detected and used by using this energy center value. The energy center value β is obtained by the following equation (3). (See Fig. 2)

[0091]

(Equation 3)

[0092]

As is apparent from the above description, the data recording apparatus according to the present invention comprises a laser irradiating means for irradiating an optical recording medium with a laser beam, and a laser beam reflected from the optical recording medium. Photoelectric conversion means for receiving a laser beam and converting it to an electric signal, and first detection means for detecting whether or not the data signal is recorded on the optical recording medium based on an output of the photoelectric conversion means, A second method for detecting an asymmetry value based on the output of the photoelectric conversion means;
Prior to recording of the data signal on the optical recording medium, the data signal is stored in an area of the optical recording medium adjacent to the area where the data signal is recorded by the first detecting means. Is detected, and when the data signal is recorded, the asymmetry value detected by the second detecting means is set to a target based on the data signal reproduced from the adjacent area. Control means for setting a predetermined asymmetry value to the target asymmetry value when the data signal is not recorded, thereby setting the asymmetry value of the additionally recorded data. Since the value can be the same as the asymmetry value of the previously recorded data, the data error rate can be reduced. That is, the quality of recorded data can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a data recording device according to the present invention.

FIG. 2 is a diagram showing a recording format of an optical disc.

FIG. 3 is a diagram illustrating a schematic configuration of an RF detection circuit.

FIG. 4 is a timing chart for explaining the operation of the RF detection circuit.

FIG. 5 is a flowchart of a first embodiment of a data recording operation procedure.

FIG. 6 is a flowchart of a data recording operation procedure according to a second embodiment.

FIG. 7 is a flowchart of a data recording operation procedure according to a third embodiment.

FIG. 8 is a flowchart of an operation procedure of data recording when data is recorded in both subcode frames.

FIG. 9 is a flowchart of an operation procedure of data recording when data is not recorded in both subcode frames.

FIG. 10 is a diagram showing signal waveforms and the like when recording and reproducing data.

FIG. 11 is a diagram illustrating an asymmetry value of an RF signal.

[Explanation of symbols]

 Reference Signs List 1 laser diode 7 optical disk 24 CPU 36 memory 37 disk detector 40 optical pickup 45 RF detection circuit 46 asymmetry detection circuit 47 memory

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Claims (6)

(57) [Claims] 1. A data recording apparatus for recording a data signal on an optical recording medium, comprising: a laser irradiation means for irradiating the optical recording medium with a laser beam; and a laser beam reflected from the optical recording medium. Photoelectric conversion means for receiving and converting the data signal into an electric signal; first detection means for detecting whether or not the data signal is recorded on the optical recording medium based on an output of the photoelectric conversion means; Second detecting means for detecting an asymmetry value based on an output of the means; and prior to recording the data signal on the optical recording medium, the first detecting means detects the data signal of the optical recording medium. It is detected whether or not the data signal is recorded in an area adjacent to the area where is recorded, and when the data signal is recorded, An asymmetry value detected by the second detection means based on the reproduced data signal is set as a target asymmetry value. When the data signal is not recorded, a predetermined asymmetry value is set to the target asymmetry value. A data recording device comprising: a control unit that sets an asymmetry value. 2. The data recording apparatus according to claim 1, wherein said control means sets a drive power of said laser irradiation means based on said target asymmetry value. 3. The control means causes the first detection means to detect whether or not the data signal is recorded in an area of the optical recording medium immediately before the area in which the data signal is recorded. 3. The data recording apparatus according to claim 2, wherein: 4. The control means causes the first detection means to detect whether or not the data signal is recorded in an area of the optical recording medium immediately after the data signal is recorded. 3. The data recording apparatus according to claim 2, wherein: 5. The controller according to claim 1, wherein the first detector detects whether the data signal is recorded in both an area immediately before and immediately after an area in which the data signal is recorded on the optical recording medium. 3. The data recording apparatus according to claim 2, wherein the data recording device detects whether or not the data is recorded. 6. The control means, wherein the first detection means records the data signal in both an area immediately before and immediately after an area of the optical recording medium in which the data signal is recorded. Is detected, the second detection means detects a first asymmetry value from a data signal reproduced from an area of the optical recording medium immediately before the area where the data signal is recorded, and Detecting a second asymmetry value from a data signal reproduced from an area of the optical recording medium immediately after the area where the data signal is recorded; and recording the data signal at the time of recording the data signal. At the beginning, the laser irradiating means is driven by the driving power set based on the first asymmetry value. There, the data recording apparatus according to claim 5, wherein the driving the laser irradiating means by said second set driving power based on the asymmetry value.