JP2001297437A - Optical recorder and optical recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To conduct the recording operation in the optimum condition by coping with the change of ambient temperature at the time of recording. SOLUTION: When the recording operation is conducted on an optical disk 100, the temperature around an optical pickup 10 is detected by a temperature sensor 50. The recording strategy of laser beams emitted from a laser source 11 is controlled in the manner of controlling a laser driving part 30 by a control part 33 in accordance with the detected temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording apparatus and an optical recording method for recording an information signal along a recording track on a disk-shaped optical recording medium.

[0002]

2. Description of the Related Art An optical recording medium has a signal recording layer and is formed in a disk shape. By irradiating the signal recording layer with a laser beam, recording and / or reproduction of an information signal (hereinafter, referred to as an information signal) is performed. This is a recording medium on which recording and reproduction are performed.

As such an optical recording medium, for example, C
D (Compact Disc) and CD-ROM (CD-Read Only Mem)
ory), there is a read-only optical disk in which pit strings corresponding to information signals to be recorded are formed in advance on a disk substrate. In such a read-only optical disk, the main surface on the disk substrate on which the pit array is formed has a function as a signal recording layer.

[0004] For example, an optical disk (hereinafter, referred to as a CD-R) to which an information signal can be additionally written has been put to practical use, which is used in a so-called compact disk recordable system. In the CD-R, a signal recording layer on which an information signal is recorded is formed of an organic dye-based material, and recording is performed by irradiating a laser beam to change the reflectance at this irradiation position. The recorded signal is reproduced by detecting the reflectance of the signal recording layer.

As an optical recording medium, CD-RW
Phase-change optical disks, such as (CD-Rewritable), in which a recording signal can be rewritten using a phase change of a signal recording layer, have been put to practical use.

[0006] CD, CD-ROM, CD as described above
Various specifications of an optical disc such as -R and CD-RW are standardized by a standard called a CD format. As a result, a CD-R or CD-RW on which an information signal can be additionally written or rewritten can be used for a read-only CD or CD-R.
It is also possible to reproduce the data by a device for reproducing the D-ROM.

[0007] The CD-R and CD-
In an optical disk device that records an information signal on an RW, usually, before actually writing the information signal, a CD is recorded.
-Performing test writing using the test writing area provided in the R or CD-RW, setting the laser beam irradiation power so that the asymmetry value is optimal, and then irradiating the laser beam with this irradiation power. Thus, the recording of the information signal is performed. In addition, in the optical disk device, during recording of the information signal, APC (Auto Power Control) is performed.
The operation is performed such that the fluctuation of the irradiation power of the laser beam is corrected according to l), and recording is always performed with a constant irradiation power.

[0008]

By the way, the optimum irradiation power at the time of recording such that the asymmetry value is optimum depends on the wavelength of the laser beam. The wavelength of the laser light has a temperature coefficient with respect to a change in the ambient temperature of the laser light source, and it is said that the wavelength increases at a rate of about 0.2 nm per 1 ° C. temperature rise, for example. Therefore, when the ambient temperature of the laser light source changes during recording by the optical disk device, the optimum irradiation power also changes. Further, the sensitivity of the signal recording layer of the optical disc also changes according to the ambient temperature.

However, in the conventional optical disk apparatus, since the irradiation power of the laser light is controlled by the APC, it is not possible to follow a change in the ambient temperature of the laser light source, and the information recording operation on the optical disk is appropriately performed. This may be difficult.

In recent years, the recording density of optical disks has been increased, and recording marks formed on a signal recording layer according to information signals to be recorded tend to be further miniaturized. Therefore, in the optical disk device, it is required to form a recording mark with higher precision as the recording density of the optical disk increases, and it becomes necessary to more precisely adjust the irradiation of the laser beam during recording. ing.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described conventional circumstances, and always performs an optimal recording operation on an optical recording medium even when the ambient temperature changes during recording. It is an object of the present invention to provide an optical recording device and an optical recording method capable of performing the above.

[0012]

An optical recording apparatus according to the present invention is an optical recording apparatus for recording an information signal along a recording track on a disk-shaped optical recording medium, comprising: a rotation driving means; It comprises a recording unit, a temperature detecting unit, and a control unit. The rotation driving means rotationally drives the optical recording medium at a predetermined speed. The recording means is movable in the radial direction of the optical recording medium, and records an information signal by irradiating a recording track of the optical recording medium with laser light. The temperature detecting means detects a temperature near the recording means. The control means controls a recording strategy of the laser beam irradiated by the recording means according to the temperature detected by the temperature detection means.

In the optical recording apparatus according to the present invention configured as described above, the control means controls the laser light recording strategy in accordance with the temperature near the recording means detected by the temperature detecting means. Even if the ambient temperature during recording changes and the wavelength of the laser beam or the sensitivity of the signal recording layer in the optical recording medium changes, the recording operation on the optical recording medium can always be performed in an optimal state. Becomes

Further, the optical recording method according to the present invention, when recording an information signal on a disk-shaped optical recording medium along a recording track, a temperature detecting step, a recording strategy setting step, an information recording step, And steps. In the temperature detecting step, the temperature in the vicinity of the recording means for irradiating the recording track of the optical recording medium with laser light is detected. In the recording strategy setting step,
According to the temperature detected in the temperature detecting step, a recording strategy of the laser beam irradiated by the recording means is set. In the information recording step, an information signal is recorded on the optical recording medium by the recording means based on the recording strategy set in the recording strategy setting step.

According to the optical recording method of the present invention as described above, the recording strategy of the laser beam can be controlled in accordance with the temperature in the vicinity of the recording means. Even when the wavelength of the laser beam or the sensitivity of the signal recording layer in the optical recording medium changes, it is possible to always perform the recording operation on the optical recording medium in an optimal state.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an optical recording apparatus and an optical recording method according to the present invention will be described in detail with reference to the drawings. Below, the CD that follows the CD format
An example in which the present invention is applied to an optical disc device 1 as shown in FIG. 1 configured to record and reproduce an information signal on an optical disc such as -R or CD-RW will be described. Will be explained.

In the following, an optical disc apparatus 1 configured to record and reproduce information on and from an optical disc 100 such as a CD-R or a CD-RW which follows the CD format will be described. The present invention is not limited to the specific examples described below, but may be applied to any optical recording device and optical recording method configured to record information signals along a recording track on a disk-shaped optical recording medium. It is possible to apply.

As shown in FIG. 1, the optical disc device 1
A spindle motor 2 is provided, and an optical disc 100 as an optical recording medium is mounted on the spindle motor 2.

The spindle motor 2 is driven by a spindle driver 3 to drive the mounted optical disc 100
For example, about 1.2 m / sec CLV (Constant Linea
r Velocity: Drive at constant linear velocity. That is, in the optical disc device 1, the spindle motor 2 has a function as a rotation driving unit that drives the optical disc 100 to rotate at a predetermined speed.

The optical disc apparatus 1 irradiates the focused optical beam onto the optical disc 100 which is driven to rotate by the spindle motor 2.
Optical pickup 1 for detecting return light reflected at 0
0 is provided. The optical pickup 10 is movable in the radial direction of the optical disk 100 by an access mechanism 35 described later, and performs recording and reproduction for recording and reproducing information signals by irradiating a recording track of the optical disk 100 with laser light. It has a function as a means.

The optical pickup 10 includes, for example, a laser light source 11 for emitting a laser beam having a wavelength of about 780 nm.
A collimator lens 12 for converting laser light emitted from the laser light source 11 into parallel light; a beam splitter 13 for splitting an optical path of the laser light converted into parallel light by the collimator lens 12;
The objective lens 14 focuses the laser light transmitted through the optical disc 3 and irradiates the optical disc 100 with the light. The condensing lens 15 focuses the return light reflected by the optical disc 100 and reflected by the beam splitter 13. And a photodetector 16 for receiving the returned light.

In the optical pickup 10 having the above-described configuration, at the time of reproduction, the laser light source 11 is driven by the laser driving section 30, and the laser light source 11 emits laser light of reproduction power (hereinafter referred to as reproduction laser light). ) Is emitted. The reproduction laser light emitted from the laser light source 11 is converted into parallel light by the collimator lens 12 and then passes through the beam splitter 13 to enter the objective lens 14. Then, the reproduction laser beam focused by the objective lens 14 is irradiated on the optical disc 100 which is driven to rotate by the spindle motor 2, and the optical disc 100
A light spot is formed along the recording track formed in the above.

The reproduction laser light applied to the optical disc 100 is reflected by the optical disc 100. At this time, the optical disc 100 is configured such that the reflectance at this position differs depending on the state of the position where the light spot is formed (the presence or absence of a recording mark or a pit). This difference in reflectance depends on the presence or absence of recording marks and pits,
That is, since the information reflected on the optical disc 100 is reflected, the return light reflected by the optical disc 100 includes a signal component.

The return light containing this signal component is reflected by the beam splitter 13 after passing through the objective lens 14, focused by the condenser lens 15, and received by the photodetector 16. The photodetector 16 has a plurality of light receiving units, and converts the return light received by the plurality of light receiving units into light voltage conversion and current-voltage conversion to generate a voltage signal corresponding to the return light. Then, the photodetector 16
Is supplied to the RF amplifier unit 31.

The RF amplifier section 31 includes a photodetector 1
6 based on the voltage signal supplied from the reproduction signal (RF
Signals), a focus error signal, and a tracking error signal. Among the various signals generated by the RF amplifier unit 31, the reproduced signal is a signal processing unit 32
And the control signal is supplied to the control unit 33.

Under the control of the control unit 33, the signal processing unit 32 corrects the waveform of the reproduced signal supplied from the RF amplifier unit 31, and then performs binarization processing to convert the reproduced signal into digital data. Convert. Then, for example, EFM (Eight to Fourteen Modulati)
on), and CIRC (Cross lnterleaveRestore)
Error correction processing using ed-Solomon Code) is performed. Further, in the signal processing unit 32, descrambling processing and ECC
Error correction processing (Error Correcting Code) is also performed.

The digital data subjected to the above-described processing in the signal processing unit 32 is temporarily stored in a buffer memory such as a RAM, and then reproduced as data through the external interface 34 of the optical disk apparatus 1. It is supplied to a host device such as a computer connected to the outside.

The control unit 33 controls the operation of the entire optical disk device 1. The control unit 33 reads an operation control program stored in the ROM or the like, and based on the operation control program, controls the entire optical disk device 1. Control the operation of.

More specifically, the control unit 33 controls the optical disc 100 mounted on the spindle motor 2 so that the optical disc 100 has a CL of, for example, about 1.2 m / sec based on the operation control program.
The drive by the spindle driver 3 is controlled so as to be driven to rotate at V. Further, the control unit 33 includes a write / read command supplied from a host computer or the like via the external interface 34 or an RF amplifier unit 31.
The operation of the access mechanism 35 is controlled in accordance with the control signal supplied from the optical pickup 10 to cause the optical pickup 10 to access a desired recording track. Further, the control unit 33 controls the operation of the Z-axis driver 36 according to the control signal supplied from the RF amplifier unit 31, and performs focus servo and tracking servo.

In recording, the control unit 33 responds to the wavelength of the laser beam detected by the wavelength detection mechanism 20, that is, the wavelength of the laser beam emitted from the laser light source 11 of the optical pickup 10 and directed to the optical disk 100. Thus, the operation of the laser driving unit 30 that drives the laser light source 11 is controlled.

As shown in FIG. 1, the optical disk device 1 is provided with a temperature sensor 50 as temperature detecting means. In the optical disk device 1, the temperature sensor 50
It is arranged near the optical pickup 10 and detects the temperature near the optical pickup 10. Then, a signal indicating the detected temperature is supplied to the control unit 33.

Then, in the optical disk device 1, when information is recorded on the optical disk 100, the control unit 33 controls the laser driving unit 30 according to the temperature detected by the temperature sensor 50, so that the laser light source 11 emits light. The recording strategy of the laser beam is controlled.

The operation of the optical disk device 1 during recording will be described below. Optical disk drive 1
During recording, a write command is sent from the externally connected host device via the external interface 34 to the control unit 3.
3 is input. In addition, data to be written (hereinafter, referred to as recording data) is supplied to the signal processing unit 32 via the external interface 34.

When a write command is supplied to the control unit 33, the spindle driver 3 drives the spindle motor 2 under the control of the control unit 33 to move the optical disc 100 mounted on the spindle motor 2 to, for example, about 1.2 m. / Sec
Is driven to rotate at CLV. At the same time, the access mechanism 35
Moves the optical pickup 10 in the radial direction of the optical disc 100 under the control of the control unit 33, and
PCA (Power Calibration)
(Area) is accessed.

Here, the laser drive unit 30 drives the laser light source 11 of the optical pickup 10 under the control of the control unit 33, and performs test writing by PCA. The control unit 33 obtains an optimum laser output such that the asymmetry value is optimum by the test writing, and sets the optimum laser output as the recording power. As described above, in the optical disk device 1, the operation of setting the optimum laser output by performing test writing using the PCA of the optical disk 100 is performed by the OPC (Op
timum Power Control).

When the test writing operation is completed, the access mechanism 35 controls the optical pickup 10 under the control of the control unit 33.
Is moved in the radial direction of the optical disc 100 to access a desired recording track of the optical disc 100.

On the other hand, the recording data supplied to the signal processing unit 32 is converted into a format corresponding to the optical disc 100 in the signal processing unit 32, and error correction coding processing by CIRC, EFM modulation processing, and the like are performed, for example. . Then, a predetermined high-frequency pulse signal is superimposed on a recording waveform corresponding to the recording data to generate a laser modulation signal, and the laser modulation signal is supplied to the laser driving unit 30.

The laser driving section 30 drives the laser light source 11 of the optical pickup 10 according to the laser modulation signal supplied from the signal processing section 32. As a result, the laser light source 11 emits a laser beam having a recording power modulated according to the recording data (hereinafter referred to as a recording laser beam).

The recording laser light emitted from the laser light source 11 is converted into parallel light by the collimator lens 12, then passes through the beam splitter 13 and passes through the objective lens 14.
Incident on. Then, the recording laser light focused by the objective lens 14 is applied to a desired recording track of the optical disc 100 that is driven to rotate by the spindle motor 2. At this time, since the recording laser light is modulated according to the recording data, a recording mark corresponding to the recording data is formed on the optical disc 100,
As a result, information is written on the optical disc 100.

At this time, the temperature sensor 50 detects the temperature in the vicinity of the optical pickup 10, and a signal indicating the detected temperature is supplied to the control unit 33. Then, the control unit 33
The laser driving unit 30 is controlled in accordance with the temperature detected by the temperature sensor 50, and the recording strategy of the laser light emitted from the laser light source 11 is controlled.

As described above, detecting the temperature in the vicinity of the optical pickup 10 and controlling the operation of the laser driving section 30 in accordance with the detected temperature is based on the fact that the optimum laser output of the recording laser light is This is because the temperature changes according to the temperature in the vicinity of 10. That is, the optical disc device 1
As described above, test writing is performed by using the PCA of the optical disc 100 before performing the actual recording operation, and the optimum laser output with which the asymmetry value is optimized is obtained. While the laser light source 1
If the wavelength of the recording laser beam changes due to a change in the ambient temperature and the like in 1, the actual optimum laser output will deviate from the optimum laser output obtained by trial writing. Further, since the sensitivity of the signal recording layer of the optical disc 100 also changes due to a change in the ambient temperature during recording, the actual optimum laser output changes from the time when test writing using PCA is performed.

As described above, when the actual optimum laser output deviates from the optimum laser output obtained by trial writing, if the recording operation is continued with the optimum laser output obtained by trial writing, the optical disc 100 Information cannot be recorded properly.

Therefore, in the optical disk apparatus 1 to which the present invention is applied, a temperature sensor 50 is provided near the optical pickup 10 to detect the temperature near the optical pickup 10 and to detect a laser in accordance with the detected temperature. Light source 1
The recording strategy of the laser light to be irradiated from 1 is controlled.

That is, as described above, the laser drive section 30 drives the laser light source 11 of the optical pickup 10 according to the laser modulation signal in which a predetermined high-frequency pulse signal is superimposed on the recording waveform corresponding to the recording data. . As described above, the superposition of the predetermined high-frequency pulse signal on the recording waveform corresponding to the recording data is performed by suppressing the accumulation of heat at the rear end portion of the recording mark formed on the signal recording layer of the optical disc 100, for example. This is for suppressing the shape distortion.

As described above, a recording technique in which a predetermined high-frequency pulse signal is superimposed on a recording waveform corresponding to recording data is called a recording strategy technique. For example, when the recording waveform corresponding to the recording data is a waveform as shown in FIG. 2A, the laser modulation signal for driving the laser light source 11 is changed according to the recording strategy, for example, as shown in FIG. Pulse signal waveform.

In the optical disk device 1, the control section 33 controls the laser driving section 30 to generate, for example, a pulse signal waveform W shown in FIG.
1 and W2 in FIG. 2 (b).
The length of the cooling pulse indicated by is controlled. Accordingly, even when the wavelength of the recording laser beam or the sensitivity of the signal recording layer of the optical disc 100 changes due to a change in the ambient temperature during recording, the recording strategy is appropriately set and the shape of the recording mark is changed. The distortion can be minimized, and the recording operation can be performed stably and reliably.

As described above, the laser driver 30 controls not only the length of the first pulse and the length of the cooling pulse but also the rising timing of each pulse and the slope of each pulse in the pulse signal waveform. It may be. That is, in the laser driving unit 30, the pulse signal waveform may be controlled in the time axis direction by being controlled by the control unit 33 according to the temperature detected by the temperature sensor 50.

Next, an example of the operation at the time of recording of the optical disk device 1 will be described step by step with reference to FIG.

In the optical disk device 1, as shown in FIG. 3, when the recording operation is started, as shown in step S70, an operation of performing test writing using the PCA of the optical disk 100 to set an optimum laser output, That is, OPC is performed.

Next, as shown in step S71, the temperature in the vicinity of the optical pickup 10 is detected by the temperature sensor 50.

Next, as shown in step S72, the control unit 33 responds to the temperature detected in step S71.
Controls the laser driving unit 30 to set the laser light source 11 to emit laser light based on a predetermined recording strategy.

Next, as shown in step S73, the laser driving unit 30 controls the recording strategy of the laser beam based on the recording strategy set in step S72, so that the laser beam is emitted from the laser light source 11. Then, an operation of recording information on the optical disc 100 is performed.

Next, as shown in step S74, the temperature near the optical pickup 10 is detected again by the temperature sensor 50.

Next, as shown in step S75, the control unit 33 calculates the temperature detected in step S75,
The difference from the temperature detected before that is calculated, and if the difference is less than the predetermined value T, the process returns to step S73 to continue the recording operation. If the calculated difference is equal to or larger than the predetermined value T, the next step S7
The process proceeds to 6.

In step S76, the control unit 33
It is determined whether or not the recording operation being performed is performed by a method of recording information on the optical disc 100 in a lump, that is, by a disc-at-once method. If the result of this determination is that the disc-at-once method is used, the process returns to step S73, and the recording operation is continued, and if not, the process proceeds to the next step S77.

In step S76, such a determination is made because, when recording is performed on the optical disk 100 by the disk-at-once method, if the recording strategy is changed during the recording operation, the reproduction is performed. This is to prevent the possibility that the operation cannot be performed.

Next, as shown in step S77, the control unit 3 determines the temperature in accordance with the temperature detected in step S74.
3 controls the laser driving unit 30 to change the setting of the recording strategy, and controls the laser light source 11 to emit the laser beam with the most appropriate recording strategy at the temperature at the time.

Next, as shown in step S78, OPC is performed again based on the recording strategy set in step S78, and the recording mark formed on the optical disc 100 is formed in a good shape according to the set recording strategy. Make sure that Thereafter, the process returns to step S73, and the recording operation is continued.

The optical disk device 1 performs the recording operation as described above.

In one example of the recording operation described above,
While performing the recording operation in step S73, step S73
At 74, the temperature near the optical pickup 10 is measured, and the setting of the recording strategy is changed as necessary. Thereby, even when the temperature fluctuates greatly during the recording operation, the optical disc apparatus 1 can change the setting of the recording strategy each time.
For example, when the time required for the recording operation is relatively long, recording on the optical disc 100 can be performed more stably and reliably. However, in the present invention, for example, the temperature at the time when the recording operation is started may be measured, and the recording operation may be performed continuously after setting the recording strategy according to the temperature at this time.

In the example of the recording operation described above, the recording strategy is reset only in step S75 when the temperature fluctuates by more than the predetermined value T. As a result, the resetting of the recording strategy is minimized and the time required for the recording operation is reduced.
It is possible to prevent endless increase by resetting the recording strategy.

Further, in the example of the recording operation described above, after the recording strategy is reset in step S77, the OPC is performed in step S78, and it is confirmed that the set recording strategy is optimal. I have to. Thereby, it is possible to more strictly adjust the irradiation of the laser beam according to the temperature at the time of performing the recording operation,
The recording operation can be performed more stably and reliably.

For example, after resetting the recording strategy in step S77, the process may return to step S73 and continue the recording operation without performing the OPC in step S78. Thus, the time required for the recording operation can be reduced by omitting the OPC.

[0064]

As described above, in the optical recording apparatus and the optical recording method according to the present invention, the recording strategy of the laser beam is controlled according to the temperature near the recording means. Accordingly, even when the ambient temperature during recording changes and the wavelength of the laser beam or the sensitivity of the signal recording layer in the optical recording medium changes, the recording operation on the optical recording medium can always be performed in an optimal state. It becomes possible. Therefore, it is easy to appropriately perform the operation of recording information on the optical recording medium, and strictly adjust the irradiation of laser light during recording to form recording marks on the signal recording layer of the optical recording medium with high precision. can do. Therefore, even when the recording density of the optical recording medium is increased, the recording operation can be stably and surely performed.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an example of the configuration of an optical disk device to which the present invention has been applied.

FIG. 2 shows a recording waveform corresponding to recording data and a laser modulation signal waveform (pulse signal waveform) for driving a laser light source.
(A) shows an example of a system according to recording data, and (b) shows an example of a laser modulation signal waveform corresponding to the system in (b). I have.

FIG. 3 is a flowchart illustrating an example of an operation at the time of recording in the optical disc device illustrated in FIG. 1;

[Explanation of symbols]

1 optical disk device, 10 optical pickup, 11
Laser light source, 30 laser driver, 33 controller, 50
Temperature sensor, 100 optical disk

Continued on the front page (72) Inventor Eiji Kumagai 6-7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (72) Inventor Yukio Shishido 6-35, Kita-Shinagawa, Shinagawa-ku, Tokyo Sony Stock Company F term (reference) 5D090 AA01 CC01 CC16 CC18 DD03 DD05 EE01 FF11 FF31 FF36 HH01 JJ02 JJ07 KK03 LL08 5D119 AA22 AA23 BA01 DA01 FA02 HA36

Claims (5)

[Claims] 1. An optical recording apparatus for recording an information signal along a recording track on a disk-shaped optical recording medium, comprising: a rotation driving means for driving the optical recording medium to rotate at a predetermined speed; A recording unit that is movable in the radial direction of the recording medium and records an information signal by irradiating a recording track of the optical recording medium with a laser beam; and a temperature detection unit that detects a temperature near the recording unit. An optical recording apparatus comprising: means for controlling a recording strategy of a laser beam irradiated by the recording means according to a temperature detected by the temperature detecting means. 2. When recording an information signal along a recording track on a disk-shaped optical recording medium, the temperature in the vicinity of a recording means for irradiating the recording track of the optical recording medium with laser light is adjusted. A temperature detection step to be detected, a recording strategy setting step of setting a recording strategy of a laser beam irradiated by the recording means in accordance with the temperature detected in the temperature detection step, and a recording set in the recording strategy setting step. An information recording step of recording an information signal on the optical recording medium by the recording means based on a strategy. 3. The optical recording method according to claim 2, wherein the temperature detecting step and the recording strategy setting step are repeatedly performed while the information recording step is performed. 4. In the recording strategy setting step, when the temperature detected in the temperature detecting step has changed by a predetermined value from the temperature detected before, the recording strategy is set. 4. The optical recording method according to claim 3, wherein the method is changed. 5. A power calibration step for calibrating the irradiation power of laser light by performing trial writing on the optical recording medium by the recording means, prior to the recording strategy setting step. The optical recording method according to claim 2.