JP2006268943A - Optical disk recording and reproducing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical disk recording and reproducing apparatus in which a recording property of overwriting recording is improved by always setting an optimum erasing power, while deterioration of durability of an optical disk is minimized. <P>SOLUTION: Reproduction is performed from an already recorded region in which overwriting recording is performed and modulation degree of the already recorded part is measured (11), recording and reproducing of a test recording region is performed using recording power of a plurality of levels, relation of modulation degree for the recording power is obtained (15), already recorded part recording power corresponding to modulation degree of the already recorded part and optimum recording power corresponding to optimum modulation degree are obtained from the relation, recording of the test recording region is performed with the already recording part recording power, overwriting recording is performed on this base region using the optimum recording power and erasing power of a plurality of levels (17), the data is reproduced and jitter is measured (12), optimum erasing power is obtained from erasing power in which a jitter value becomes the prescribed jitter value or less (16). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical disc recording / reproducing apparatus for recording on a rewritable optical disc, and more particularly to a recording power calibration operation called OPC (Optimum Power Control).

The recordable optical disc includes a write once type and a rewritable type. Among these, for overwriting (overwriting) of a rewritable optical disk, as shown in FIG. 6, a laser beam whose laser power changes with two values of recording power Pw and erasing power Pe is used. In this case, the state of the recording film of the optical disk changes from the crystalline state to the amorphous state by the recording power Pw to form pits, and the pit is formed by changing from the amorphous state to the crystalline state by the erasing power Pe. .
The optimum recording power Pwo and optimum erasing power Peo of the laser beam at the time of optical disc overwrite recording differ depending on the type of optical disc, the recording speed, and the recording apparatus. For this reason, prior to recording information, a recording apparatus that actually performs recording performs a recording power calibration operation called OPC, sets an optical disc, an optimum recording power Pwo that matches the recording speed, and an optimum erasing power Peo, The recording data is overwritten.

In this OPC, the optimum value of the characteristic parameter indicating the quality of the recording state is stored in the memory of the recording apparatus, test recording is performed with the optimum value as a target, and the optimum recording power is set. The optimum value of the characteristic parameter is obtained in advance for each combination of the type of optical disk medium and the recording speed through experiments.
However, since the optical disk medium is exchangeable, the medium is recorded by various types of recording devices, and the recorded power varies. When overwriting is performed on an area already recorded on the medium, if the recording power of this area is high, the area cannot be completely erased unless it is erased with a somewhat high erasing power. In addition, if the recording power and the erasing power for overwriting are set to be high in order to improve the recording characteristics at the time of overwriting, there is a problem that the depth of pit recording becomes large and the durability of the optical disk deteriorates. .

Therefore, an optical disc recording apparatus has been proposed (see, for example, Patent Document 1) in which the OPC operation is devised to improve the recording characteristics of overwrite recording and the durability of the optical disc, and an example thereof will be described below.
First, the recorded area to be overwritten from now on is reproduced, and the modulation degree Mini of the recorded part is measured. Further, the target modulation degree Mwo corresponding to the medium type and the recording speed is read, and the values of Mini and Mwo are stored. Then, the recording power Pw is changed, the test signal is recorded / reproduced, the modulation degree M for each recording power is measured, and the characteristic indicating the relationship between the recording power Pw and the modulation degree M as shown in FIG. 4 is obtained. From the above characteristics, the recording power Pini of the recorded part corresponding to the modulation degree Mini of the recorded part and the optimum recording power Pwo corresponding to the target modulation degree Mwo are obtained.
Next, the recording power is determined as follows according to the modulation degree Mini and the target modulation degree Mwo.
When Mwo ≧ Mini, the recording power Pw is set to a recording power Pini that is lower than the optimum recording power Pwo measured by the OPC operation. In the case of Mwo <Mini, the recording power Pw is set to a power that is lower than the recording power Pini at the previous recording by a certain rate. The erasing power Pe is calculated from the overwrite recording power Pw using a coefficient (erasing / recording power ratio) recorded as ATIP information on the optical disc and a coefficient κ (erasing / recording power ratio compensation coefficient for low-speed recording). Set.
Thus, it is described that the durability of the disk and the recording apparatus can be secured while keeping the recording power as small as possible and maintaining the recording characteristics in a good state.
Japanese Patent Laid-Open No. 2001-351249 (page 5-7, FIG. 1-3)

However, in the conventional example, the recording power is kept as low as possible to improve the durability. However, the erasing power is set only by multiplying the recording power by a predetermined coefficient. It is. For this reason, the erasing power is not necessarily set to the optimum erasing power when the recording conditions such as the ambient temperature and the aging of the recording apparatus change.

  Therefore, the present invention has been made to solve the above-described problems, and is always set to an optimum erasing power to improve the recording characteristics of overwrite recording and minimize deterioration in durability of the optical disk. It is an object of the present invention to provide an optical disk recording / reproducing apparatus held down.

According to a first aspect of the present invention, in an optical disk recording / reproducing apparatus that performs overwrite recording on an already recorded area of an optical recording medium, information recorded on an already recorded part is reproduced by reproducing the already recorded area scheduled to be overwritten. And recording / reproducing the test recording area of the optical disc using a modulation degree measurement unit (modulation degree measurement unit 11) for measuring the modulation degree of the optical disc and a plurality of predetermined levels of recording power. Control means (OPC & power setting unit 17) for storing the recording power in the memory, reading the plurality of recording powers stored in the memory, measuring the degree of modulation for the plurality of recording powers, From the first calculation means (modulation degree related calculation unit 15) for obtaining the relationship of the modulation degree with respect to the recording power and the relationship of the modulation degree with respect to the plurality of recording powers, The recorded part recording power calculation means (modulation degree related calculation part 15) for obtaining the recorded part recording power corresponding to the modulation degree of the information recorded in the recording part, and the recorded part recording power calculation means First instruction means (OPC & power setting section 17) for outputting an instruction signal for recording in the test recording area to the control means at the already-recorded part recording power, and the first operation means An optimum recording power acquisition means (modulation degree related calculation section 15) for obtaining an optimum recording power corresponding to the optimum modulation degree determined when recording / reproducing information on the optical disc from the relationship of the modulation degree with respect to a plurality of recording powers; Overwriting recording means (OP) for performing overwriting recording on the information recorded in the test area using the optimum recording power and a plurality of predetermined erasing powers & Power setting unit 17), jitter measurement means (jitter measurement unit 12) for reproducing the information recorded in the test area by overwriting, and measuring the jitter and the plurality of jitters measured by the jitter measurement means The optimum erasing power is obtained from the second computing means (jitter-related computing unit 16) for obtaining the relationship with the erasing power, and from the erasing power that is not more than a predetermined jitter value based on the relationship between the plurality of erasing power and jitter An instruction signal for overwriting the already recorded area of the optical disc is output to the control means using the optimum erasing power acquisition means (jitter-related calculating section 16) and the optimum recording power and the optimum erasing power. Instruction means (OPC & power setting unit 17);
An optical disc recording / reproducing apparatus characterized by comprising:

According to the present invention, a modulation degree measurement unit that reproduces a recorded area that is scheduled to be overwritten and measures the modulation degree of information recorded in the recorded part, and a plurality of predetermined levels of recording Control means for recording / reproducing the test recording area of the optical disc using power, storing the plurality of levels of recording power in a memory, and reading the plurality of recording powers stored in the memory; The first calculation means for measuring the modulation degree for the plurality of recording powers to obtain the relationship of the modulation degree for the plurality of recording powers, and the relationship between the modulation degrees for the plurality of recording powers. A recorded portion recording power calculating means for obtaining a recorded portion recording power corresponding to the modulation degree of the recorded information, and the recorded portion recording power calculated by the recorded portion recording power calculating means. From the relationship between the first instruction means for outputting an instruction signal for recording in the test recording area to the control means, and the degree of modulation for the plurality of recording powers obtained by the first arithmetic means, the optical disc Using the optimum recording power acquisition means for obtaining the optimum recording power corresponding to the optimum degree of modulation determined when recording / reproducing the information of the information, and using the optimum recording power and a plurality of predetermined erasing powers, Overwrite recording means for performing overwriting on the information recorded in the area, jitter measuring means for measuring the jitter by reproducing the information overwritten in the test area, and the jitter measuring means Second calculating means for obtaining a relationship between the determined jitter and the plurality of erase powers, and a predetermined jitter value or less based on the relationship between the plurality of erase powers and the jitter. An optimum erasing power acquisition means for obtaining an optimum erasing power from the erasing power to be used, and an instruction signal for overwriting the already recorded area of the optical disc using the optimum recording power and the optimum erasing power. Second output means for outputting,
It is possible to provide an optical disc recording / reproducing apparatus that always sets the optimum erasing power to improve the recording characteristics of the overwrite recording and minimizes the deterioration of the durability of the optical disc.
In this method, since the optimum overwrite power is obtained on the spot, the optimum overwrite recording power can always be obtained even if the recording conditions change such as the ambient temperature and the aging of the recording apparatus. Furthermore, the optimum overwrite recording power can be obtained for a medium unknown to the recording / reproducing apparatus (such as a medium released after the development of the recording / reproducing apparatus).

Hereinafter, an optical disk recording / reproducing apparatus according to an embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a block diagram showing the structure of an optical disk recording / reproducing apparatus according to the present invention. 2 and 3 are flowcharts showing the OPC operation during overwrite recording. FIG. 4 is a diagram showing the relationship between the recording power and the modulation degree obtained in the test recording / reproducing of the OPC operation. FIG. 5 is a diagram showing the relationship between the erasing power and jitter obtained by test recording / reproduction in the OPC operation.
The present invention seeks optimum overwriting power consisting of recording power and erasing power on the spot,
Embodiments of the present invention will be described below with reference to the drawings. The characteristic parameter indicating the quality of the recording state is a modulation degree M.
Example 1

  As shown in FIG. 1, an optical disk recording / reproducing apparatus according to the present invention includes an optical disk 1, a spindle motor 2, an optical pickup 3, a motor driver 4, an optical PU feed controller 5, a servo system 6, a head amplifier reproducing system 7, and an LD driver. 8, a data decoding unit 9, a recording encoding unit 10, a modulation degree measuring unit 11, a jitter measuring unit 12, and a system controller 13 for controlling them. Furthermore, the system controller 13 includes a recording information memory 14, a modulation degree related calculation unit 15, a jitter related calculation unit 16, an OPC & power setting unit 17, and a control unit 18.

At the time of recording / reproducing, the optical pickup 3 emits the laser beam driven by the LD driver 8 to the optical disc 1 and detects the reflected light by a photodetector to produce a reproduction RF signal, which is output to the head amplifier detection system 7. . Based on the reproduction RF signal, the head amplifier detection system 7 generates and outputs a reproduction signal, a focus error signal, a tracking error signal, a preformat signal such as a land prepit, and other control signals.
The system controller 13 drives the spindle motor 2 by the motor driver 4 to rotate the optical disk at a predetermined speed, and condenses the laser beam at a predetermined address position by the optical pickup feed control unit 5. The servo system 6 controls tracking and focus.
Thus, at the time of recording, the recording data is encoded as a recording signal by the recording encoding unit 10 and recorded by the optical pickup via the LD driver. During reproduction, the reproduction signal output from the head amplifier reproduction system is decoded by the data decoding unit 9 and output as reproduction data.

During the OPC operation, the reproduction signal output from the head amplifier reproduction system 7 is output to the modulation degree measurement unit 11 and the jitter measurement unit 12 under the control of the system controller.
The modulation degree measurement unit measures the modulation degree M of the reproduction signal and outputs it to the OPC & power setting unit 17. The OPC & power setting unit sets the optimum recording power Pwo based on the modulation degree M and supplies the optimum recording power Pwo to the LD driver 8 as described later.
The jitter measuring unit measures the jitter J of the reproduction signal and outputs it to the OPC & power setting unit 17. The OPC & power setting unit sets the optimum erase power Peo based on the jitter J and supplies the optimum erase power Peo to the LD driver 8 as described later.

In the recording information memory 14 of the system controller, as a ROM (Read Only Memory), an optical disk type (ID number), an M value (target modulation degree Mwo) table corresponding to the recording speed, and an optical disk type A table in which the OPC start power, step power, and ratio between the recording power and the erasing power are set is stored. Further, a past OPC history, that is, an optimum recording power measured in the past is stored as a RAM (Random Access Memory). This OPC history is held for a certain period of time.

In the present invention, a state in which a state of an area to be overwritten (hereinafter referred to as a background) of an optical disk is simulated in advance is created in a test recording area, the background is divided into finer areas, and the erasing power is divided for each area. This is characterized in that overwriting is performed with different values, jitter is measured for each of the areas, the optimum erasing power is obtained for overwriting recording of the ground, and overwriting is performed. The OPC operation during overwrite recording will be described below with reference to the flowcharts of FIGS.

In the case of overwriting in an already recorded area, before overwriting is started, the overwriting OPC operation is started, overwriting power consisting of recording power and erasing power is set, and overwriting is started.
In FIG. 2, the system controller reproduces a block having a predetermined length from a position where overwrite recording of an already recorded area where pits have already been recorded is started (step S1).
Next, the modulation degree Mini of the reproduction part is measured from the reproduction signal (step S2).
Next, the recording speed is set to a value specified by the recording command, an ID number recorded as LPP (Land Pre-Pit) information is acquired from the optical disc, and the type of optical disc (type of media) is determined (step). S3).
Next, the target modulation degree Mwo is referred to by referring to the table of the recording information memory of the system controller in which the M value (target modulation degree Mwo) corresponding to the medium type and the recording speed is set in advance by the medium type and the recording speed. Is read (step S4).
Then, a table in the recording information memory of the system controller corresponding to the recording speed is selected, and the recording power Pw is changed in 16 steps in units of step power from the start power set in the selected table, thereby performing test recording on the optical disc. A test signal is recorded in the area (step S5). At this time, in this embodiment, the erasing power Pe is set in 16 steps while the ratio of the recording power Pw and the erasing power Pe is read from the table in the recording information memory of the system controller and the ratio is kept constant.
Next, the recording portion of the test signal is reproduced and the modulation degree M is measured for each of the 16 recording powers Pw to obtain the modulation degree characteristic with respect to the recording power as shown in FIG. 4 (step S6).
Then, the recording power Pini corresponding to the modulation degree Mini (value obtained in step S2) is obtained from the modulation degree M (characteristic shown in FIG. 4) for each of the 16 recording powers Pw (step S7).
Next, the optimum recording power Pwo corresponding to the target modulation degree Mwo is obtained from the modulation degree characteristic with respect to the recording power shown in FIG. 4 (step S8).
As described above, the recording power Pini and the optimum recording power Pwo of the already recorded part are obtained.

Further, in FIG. 3, recording is performed in the test recording area with the recording power Pini of the already-recorded portion, and a base A is created (step S11).
The base A is further divided into areas A0 to A15 (step S12).
Next, the recording power is fixed to Pwo, the erasing power combined therewith is set to Pe0 to Pe15 for each step power, and overwriting is performed on A0 to A15 with each combination of powers while varying the erasing power (step S13).
Then, jitter is measured for each of the areas A0 to A15 to obtain jitter characteristics with respect to the erasing power as shown in FIG. 5 (step S14).
Based on the jitter characteristic with respect to the erasing power obtained at this time, the erasing power Pe that satisfies a predetermined jitter margin (in this embodiment, the middle point of the set jitter margin) is set as the final optimum erasing power Peo for overwrite ( Step S15).
Thus, the optimum erasing power Peo is obtained, and the OPC at the time of overwriting is completed. Actual overwriting of the recording data may be performed with the optimum recording power Pwo and the optimum erasing power Peo.
In the case of recording in an unrecorded area, the recording power is set to the optimum recording power Pwo, and the erasing power Peo is a recording power and erasing corresponding to the recording speed stored in the recording information memory 14 and the type of the optical disk. The erase power calculated from the optimum recording power Pwo may be set using the power ratio.

As described above, according to the first embodiment of the present invention, since there is the above-described configuration, by setting the recording power Pwo and erasing power Peo at the time of overwriting, the unerased residue at the time of overwriting can be minimized. be able to. Further, since the overwrite recording is not simply performed with a strong power, there is an effect that the durability of the disk and the recording apparatus can be secured while maintaining the recording characteristics in a good state.
Also, since this method obtains the optimum overwrite power on the spot, the optimum overwrite recording power can always be obtained even if the recording conditions change such as the ambient temperature and the aging of the recording apparatus. In addition, the optimum overwrite recording power can be obtained for a medium unknown to the recording / reproducing apparatus (such as a medium released after the development of the recording / reproducing apparatus).

It is a block block diagram which shows the structure of the optical disk recording / reproducing apparatus in embodiment of this invention. 6 is a flowchart showing an operation of setting recording power by OPC at the time of overwrite recording in the optical disc recording / reproducing apparatus of the present invention. 6 is a flowchart showing an operation of setting an erasing power by OPC at the time of overwrite recording in the optical disc recording / reproducing apparatus of the present invention. It is a figure which shows the relationship between the recording power obtained by the test recording / reproducing of OPC operation | movement in the optical disk recording / reproducing apparatus of this invention, and a modulation degree. It is a figure which shows the relationship between the erasing power and jitter obtained by the test recording / reproducing of OPC operation in the optical disc recording / reproducing apparatus of the present invention. FIG. 2 is an explanatory diagram of overwrite recording power in the optical disc recording / reproducing apparatus of the present invention, where (A) shows an overwrite recording waveform and (B) shows a pit waveform.

Explanation of symbols

1 optical disk, 2 spindle motor, 3 optical pickup, 4 motor driver, 5 optical PU feed control unit, 6 servo system, 7 head amplifier reproduction system, 8 LD driver, 9 data decoding unit, 10 recording encoding unit, 11 modulation Degree measurement unit, 12 Jitter measurement unit, 13 System controller, 14 Recording information memory, 15 Modulation degree related calculation unit, 16 Jitter related calculation unit, 17 OPC & power setting unit, 18 Control unit

Claims (1)

In an optical disc recording / reproducing apparatus that performs overwrite recording on an already recorded area of an optical recording medium,
A modulation degree measurement unit that reproduces an already recorded area that is scheduled to be overwritten and measures the modulation degree of information recorded in the recorded part;
Control means for recording and reproducing the test recording area of the optical disc using a plurality of predetermined levels of recording power, and storing the plurality of levels of recording power in a memory;
First calculation means for reading the plurality of recording powers stored in the memory, measuring a degree of modulation with respect to the plurality of recording powers, and obtaining a relationship of the degree of modulation with respect to the plurality of recording powers;
From the relationship of the modulation degree with respect to the plurality of recording powers, the recorded part recording power calculation means for obtaining the recorded part recording power corresponding to the modulation degree of the information recorded in the recorded part;
First instruction means for outputting, to the control means, an instruction signal for performing recording in the test recording area with the recorded part recording power calculated by the recorded part recording power calculating means;
Obtaining the optimum recording power for obtaining the optimum recording power corresponding to the optimum degree of modulation determined when recording / reproducing information on the optical disc from the relationship of the degree of modulation to the plurality of recording powers obtained by the first calculating means Means,
Overwriting recording means for performing overwriting recording on the information recorded in the test area, using the optimum recording power and predetermined multiple levels of erasing power;
Jitter measurement means for measuring the jitter by reproducing the information recorded overwritten in the test area,
Second computing means for obtaining a relationship between the jitter measured by the jitter measuring means and the plurality of erasing powers;
Based on the relationship between the plurality of erasing power and jitter, an erasing power that is equal to or lower than a predetermined jitter value, an optimum erasing power acquisition means for obtaining an optimum erasing power;
Second instruction means for outputting, to the control means, an instruction signal for overwriting the already recorded area of the optical disc using the optimum recording power and the optimum erasing power;
An optical disc recording / reproducing apparatus comprising: