JP3873672B2 - Optical disk device - Google Patents

Description

表１において、ランド記録時におけるプリピット基準再生パワーはＰｐｒＬ、消去時におけるプリピット基準再生パワーはＰｐｅＬであり、例えばＰｐ＞ＰｐｒＬ＞ＰｐｅＬとすることができる。グルーブ記録においては、記録時におけるプリピット基準再生パワーはＰｐｒＧ、消去時におけるプリピット基準再生パワーはＰｐｅＧであり、Ｐｐ＞ＰｐｒＧ＞ＰｐｅＧとすることができる。表１では全てのパワーを基準エラーレートに応じて設定しているが、少なくともいずれか、例えばランド記録の記録パワーを基準エラーレートに応じて設定することもできる。
【００４２】
なお、本実施形態では再生パワーを小さくする場合について例示したが、再生条件を劣化させるための他の条件、例えば通常の再生パワーで再生して得られたＲＦ信号の所定周波数帯域をブーストするフィルタブーストの量を低減する、あるいはフィルタのカットオフ周波数を変更してノイズ成分を意図的に増大させる、あるいはディスク回転数を変動させる等も可能である。
【００４３】
【発明の効果】
以上説明したように、本発明によれば、光ディスク毎に最適な記録パワーあるいは消去パワーを設定することができる。
【図面の簡単な説明】
【図１】 実施形態における光ディスク装置の要部構成ブロック図である。
【図２】 図１におけるエラーレート検出部の構成ブロック図である。
【図３】 図１における処理部の構成ブロック図である。
【図４】 光ディスク装置の構成図である。
【図５】 処理部の処理フローチャートである。
【図６】 記録パワーとエラーレートとの関係を示すグラフ図である。
【図７】 基準エラーレートと最適パワーとの関係を示す説明図である。
【図８】 光ディスクＡと光ディスクＢの特性を示す説明図である。
【符号の説明】
１０ スピンドルモータ、１２ 光ピックアップ部、１４ エラーレート検出部、１６ 処理部。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to power optimization of an optical disk apparatus, and more particularly to an apparatus for recording on a recordable optical disk.
[0002]
[Prior art]
Conventionally, a recordable or rewritable optical disc apparatus is known and has been commercialized as a DVD-RAM or the like.
[0003]
In order to record data on such a recordable or rewritable optical disk with high quality, it is necessary to optimize the recording power. Conventionally, for example, the recording power is recorded on the control track provided on the inner periphery of the optical disk. Is written in advance, and this recording power data is read to set the recording power.
[0004]
However, in the above method, even if there is a drive variation, recording is performed with the same recording power, and there is a problem that stable recording characteristics cannot be obtained or the number of rewrites is reduced.
[0005]
Therefore, as described in, for example, Japanese Patent Application Laid-Open No. 2000-137918, a mark is recorded by changing the recording power in the power calibration area or test area of the optical disc, and this mark is reproduced to measure jitter. There has been proposed a technique for recording data using a recording power that minimizes the recording power as an optimum recording power.
[0006]
[Problems to be solved by the invention]
However, even if the recording power is changed and the mark is recorded and the jitter is reproduced by reproducing the mark, the recording power that minimizes the jitter is not always detected, and the optimum power cannot be obtained. was there. In other words, even if the mark is recorded by changing the recording power, the jitter may not change so much and a flat pan bottom characteristic may be obtained. In this case, for example, the maximum value or intermediate value of the flat recording power range is optimal. Even if the power is determined, there is a problem that it becomes excessive power from the viewpoint of durability. The same applies to the erasing power. Even if the error rate is used as an evaluation criterion instead of jitter, the same problem may occur.
[0007]
The present invention has been made in view of the above-mentioned problems of the prior art, and an object thereof is to provide an optical disc apparatus capable of setting an optimum recording power or erasing power for each optical disc.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a means for reproducing an embossed portion of an optical disk by deteriorating reproduction conditions and detecting the error rate as a reference error rate, and changing a recording power in a predetermined area of the optical disk. A means for recording, a means for storing the relationship between each recording power and the error rate when the recording power is changed, and a recording for obtaining the reference error rate based on the relationship between each recording power and the error rate Means for selecting power, and data is recorded on the optical disc with the selected recording power.
[0009]
Further, the present invention provides a means for reproducing the embossed portion of the optical disk by degrading the reproduction condition and detecting the error rate as a reference error rate, a means for overwriting by changing the erasing power in a predetermined area of the optical disk, Means for storing the relationship between each erase power and error rate when the erase power is changed, and means for selecting an erase power that provides the reference error rate based on the relationship between each erase power and error rate And erasing data on the optical disc with a selected erasing power.
[0010]
In the present invention, the deterioration of the reproduction condition can be achieved by reproducing with a power smaller than the reproduction power.
[0011]
In the present invention, the degradation of the regeneration condition can be achieved by the degradation of the filter characteristics for regeneration. The deterioration of the reproduction filter characteristic is, for example, setting a boost amount lower than the optimum boost amount of the filter, or changing the optimum cutoff frequency of the filter to increase the noise component.
[0012]
In the present invention, it is preferable that the reference error rate is detected in accordance with land recording and groove recording.
[0013]
As described above, in the optical disc apparatus of the present invention, the reproduction condition is deteriorated, the embossed portion is reproduced, the error rate is detected, and the power is optimized using the error rate as a reference value. The error rate obtained by reproducing the embossed part with the reproduction power is an error rate under favorable conditions, and is a value unique to the optical disc. The error rate of normal recording data is larger than this. Therefore, by deliberately degrading the reproduction conditions of the embossed portion and reproducing the reference error rate, a reference error rate suitable for the optical disc and the optical disc apparatus can be set, and the power can be optimized.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings, taking as an example the case of recording on a phase change type rewritable optical disc.
[0015]
FIG. 1 shows a configuration diagram of a main part of an optical disc apparatus according to the present embodiment. The optical disc apparatus includes an optical pickup unit 12, an error rate detection unit 14, and a processing unit 16.
[0016]
The optical pickup unit 12 performs recording or reproduction by irradiating the optical disk 100 rotated by the spindle motor 10 with laser light, and outputs a reproduction RF signal to the error rate detection unit 14. The laser power includes a bias level, an erase level, and a peak level. Playback is performed at the bias level, erase is performed at the erase level, and recording is performed at the peak level.
[0017]
The error rate detection unit 14 detects the error rate of the reproduction RF signal from the optical pickup unit 12. There are two types of error rates detected by the error rate detection unit 14, the first is the error rate of the reproduction RF signal obtained by reproducing the embossed part of the optical disc 100, and the second is various in the test area of the optical disc 100. This is an error rate of a reproduction RF signal obtained by reproducing a mark recorded with recording power. The error rate of the embossed part and the error rate of the test area are supplied to the processing part 16.
[0018]
The processing unit 16 selects the optimum recording power based on the detected error rate. Specifically, the error rate of the embossed portion is set as a reference error rate, and the recording power that can obtain this reference error rate is selected. The selected recording power is supplied to the optical pickup unit 12, and the power of the laser diode is controlled.
[0019]
In addition, the optical disk apparatus includes a servo circuit that extracts the focus error signal and the tracking error signal to control the focus and tracking of the optical pickup unit 12, but these are the same as those in the prior art. Description is omitted.
[0020]
FIG. 2 is a block diagram showing the configuration of the error rate detection unit 14 in FIG. The error rate detector 14 includes a binarization circuit 14a for binarizing the reproduced RF signal, a demodulator circuit 14b for demodulating data from the binarized RF signal, and an error for performing predetermined error correction on the demodulated reproduction data A correction circuit 14c is included. The error correction circuit 14c counts the number of bits subjected to error correction by the error correction process, and outputs it to the processing unit 16 as an error rate.
[0021]
FIG. 3 shows a configuration block diagram of the processing unit 16 in FIG. The processing unit 16 is specifically composed of a microcomputer, and includes a storage unit 16a for storing the input error rate and a power selection unit 16b for selecting the optimum recording power based on the error rate stored in the storage unit 16a. Have.
[0022]
In addition to the error rate obtained by reproducing the embossed part of the optical disc 100, the storage unit 16a stores an error rate obtained by reproducing a mark recorded by changing the recording power in the test area of the optical disc 100. . The error rate obtained by reproducing the mark recorded in the test area is stored in association with the recording power. For example, the two-dimensional data is (power P0, error rate E0), (power P1, error rate E1). The relationship between the recording power and the error rate can be approximated by a function and stored as a parameter of this function.
[0023]
The power selection unit 16b sets the error rate of the embossed part stored in the storage unit 16a as a reference error rate, and sets the recording power corresponding to the reference error rate between the recording power and the error rate stored in the storage unit 16a. Seek from relationship.
[0024]
In the present embodiment, the embossed portion is an information pit (pre-pit) formed in advance in the control data zone 102 formed in the inner peripheral portion of the optical disc 100 or data on the optical disc 100 as shown in FIG. It means an information pit (pre-pit) formed in advance at the head of the sector 104 in the recording area, and when detecting an error rate of the embossed part, the information pit of the control track 102 may be reproduced, Alternatively, the information pits in the sector 104 may be reproduced. It is also possible to use these properly depending on the case.
[0025]
In this embodiment, when the error rate (reference error rate) of the embossed portion is detected, the reproduction power is not reproduced with a certain (optimum) reproduction power as in the conventional optical disc apparatus. Is reproduced with the error rate reduced, and the error rate is detected from the reproduced RF signal.
[0026]
Since the data of the embossed part is preliminarily formed, it can always be reproduced under better conditions than pits recorded by changing the state of the recording film later (transition between the amorphous state and the crystalline state). That is, when the recorded pit is reproduced, the error rate is always higher than the error rate of the embossed portion. The error rate of the embossed portion is considered to be a value unique to the optical disc 100, and can be considered as the reproduction characteristic of the optical disc.
[0027]
Therefore, when playing the embossed part, the playback power is deliberately reduced to degrade the playback conditions. In other words, the error rate is detected by reproducing the same conditions as when recording pits are played back. As a result, the error rate of the recording pit is evaluated.
[0028]
Hereinafter, the operation of the processing unit 16 in the present embodiment will be described in more detail.
[0029]
FIG. 5 shows a process flowchart of the processing unit 16. First, the processing unit 16 determines the reproduction power (reference power) for detecting the error rate of the embossed part (prepit). Specifically, a power that is reduced by a predetermined amount from the optimized reproduction power is set (S101). Of course, it is also possible to decrease by a predetermined ratio instead of decreasing by a predetermined amount. Also, using a coefficient D smaller than 1,
[Expression 1]
Reference power = Pp · D (1)
The power may be determined by Here, Pp is the reproduction power. For example, D can be set to 0.5. In this case, the pre-pit is reproduced with a power half the normal reproduction power.
[0030]
After determining the power, the optical pickup 12 is driven to reproduce the prepit (S102). Then, the error rate is detected from the reproduced RF signal obtained at this time, and stored in the storage unit 16a as the reference error rate Er (S103). The reference error rate Er differs for each optical disc 100 and is larger than the error rate when the embossed part is reproduced with reproduction power.
[0031]
Next, the processing unit 16 drives the optical pickup 12 to form a mark by variously changing the recording power in a test area formed in a predetermined area of the optical disc 100, and reproducing the mark to set an error rate. Detect and store in the storage unit 16a (S104). When the error rate of the mark recorded in the test area is detected, the power is returned to the normal reproduction power Pp and detected.
[0032]
FIG. 6 shows error rates E0 to E2 obtained by recording marks in the test area while changing the recording power from P0 to P2, and reproducing each mark with the reproduction power. The horizontal axis is the recording power (mW), and the vertical axis is the error rate. In general, the error rate decreases as the recording power increases, and eventually becomes a constant value. In consideration of durability (number of rewrites) and the like, it is desirable to record with as little power as possible while keeping the error rate below a certain value.
[0033]
Returning to FIG. 5 again, the processing unit 16 stores the relationship between the recording power and the error rate, and then uses this relationship to select the recording power (optimum recording power) at which the reference error rate Er is obtained, thereby selecting the optical pickup unit 12. The power of the laser diode is controlled (S105). When the correspondence between the recording power and the error rate is stored discretely (Pi, Ei) (i = 1, 2,...) In the storage unit 16a, the recording corresponding to the error rate Er is performed. The power may be calculated by interpolation processing.
[0034]
FIG. 7 shows the relationship between the reference error rate Er and the optimum recording power Pd described above. For comparison, the figure also shows the error rate Er0 when the embossed part is reproduced with the normal reproduction power Pp. The error rate Er0 of the embossed portion (prepit) is a value determined by the combination of the optical disc 100 and the optical disc device, and the reference error rate Er obtained when the reproduction power is reduced is also a characteristic value determined by the combination of the optical disc 100 and the optical disc device. is there. The recording power Pd is optimized using the reproduction characteristic value as a reference error rate. Note that the recording power Pd is not determined based on a fixed threshold error rate, but dynamically changes according to the error rate at the embossed portion.
[0035]
As described above, in this embodiment, since the recording power is optimized based on the error rate obtained by reproducing the embossed portion of the optical disc 100, it is possible to cope with the case of recording data on another optical disc 100. .
[0036]
FIG. 8 shows characteristics when data is recorded on the optical disc A and the optical disc B. In the figure, the solid line is the characteristic of the optical disc A, and the alternate long and short dash line is the characteristic of the optical disc B. In the optical discs A and B, the error rates Er obtained by reproducing the embossed portions with the same power are different from those of Era and Erb, respectively. Due to this, the optimum recording power is also Pda and Pdb, respectively. If the threshold error rate is set to a fixed value, it can be understood from the figure that even though the optimum recording power can be obtained with the optical disc B, the error rate with the optical disc A is originally large and the recording power may become excessive. Let's be done.
[0037]
Although the embodiment of the present invention has been described with respect to the case where the recording power is optimized, the erasing power when overwriting (overwriting) the previously recorded data can be similarly optimized.
[0038]
In this case, it is preferable that the power when the embossed part is reproduced and the reference error rate is detected is further smaller than the power when the recording power is optimized. The reason is that, at the time of overwriting, the already recorded data is erased and new data is recorded, so that the error rate is generally higher than when the data is recorded from a state where nothing is recorded. Because it becomes. Therefore, when the embossed portion is reproduced, it is desirable to reproduce with a smaller power, so to speak, the conditions at the time of overwriting are reproduced by further degrading the conditions, and the reference error rate is set.
[0039]
Note that either the recording power or the erasing power may be set based on the reference error rate, and both the recording power and the erasing power may be set based on the reference error rate.
[0040]
Also, in the DVD-RAM, when data is recorded on the optical disc 100, data is recorded on both the land portion and the groove portion of the optical disc 100. The characteristics depend on whether the data is recorded on the land portion or the groove. Therefore, it is also preferable to set the optimum recording power at the time of land recording (optimum erasing power) and the optimum recording power at the time of groove recording (optimum erasing power) by performing the above processing in the land portion and the groove portion, respectively. . In this case, the reference error rate can be detected by reproducing the embossed portion with different powers in the land portion and the groove portion. Table 1 summarizes various parameters used in the processing unit 16.
[0041]
[Table 1]

In Table 1, the prepit reference reproduction power at the time of land recording is PprL, and the prepit reference reproduction power at the time of erasure is PpeL. For example, Pp>PprL> PpeL. In groove recording, the prepit reference reproduction power at the time of recording is PprG, the prepit reference reproduction power at the time of erasure is PpeG, and Pp>PprG> PpeG. In Table 1, all powers are set according to the reference error rate, but at least one of them, for example, the recording power of land recording can be set according to the reference error rate.
[0042]
In the present embodiment, the case where the reproduction power is reduced is illustrated, but other conditions for degrading the reproduction condition, for example, a filter for boosting a predetermined frequency band of an RF signal obtained by reproduction with normal reproduction power. It is possible to reduce the amount of boost, or to intentionally increase the noise component by changing the cutoff frequency of the filter, or to change the disk rotation speed.
[0043]
【The invention's effect】
As described above, according to the present invention, the optimum recording power or erasing power can be set for each optical disc.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a main part of an optical disc apparatus according to an embodiment.
FIG. 2 is a block diagram showing the configuration of an error rate detection unit in FIG. 1;
3 is a configuration block diagram of a processing unit in FIG. 1. FIG.
FIG. 4 is a configuration diagram of an optical disc device.
FIG. 5 is a processing flowchart of a processing unit.
FIG. 6 is a graph showing the relationship between recording power and error rate.
FIG. 7 is an explanatory diagram showing a relationship between a reference error rate and optimum power.
FIG. 8 is an explanatory diagram showing characteristics of an optical disc A and an optical disc B.
[Explanation of symbols]
10 spindle motor, 12 optical pickup unit, 14 error rate detection unit, 16 processing unit.

Claims (5)

Means for reproducing the embossed portion of the optical disk by degrading the reproduction conditions and detecting the error rate as a reference error rate;
Means for changing and recording power in a predetermined area of the optical disc;
Means for storing a relationship between each recording power and an error rate when the recording power is changed;
Based on the relationship between each recording power and an error rate, means for selecting a recording power at which the reference error rate is obtained;
And recording data on the optical disc with a selected recording power. Means for reproducing the embossed portion of the optical disk by degrading the reproduction conditions and detecting the error rate as a reference error rate;
Means for changing and erasing power in a predetermined area of the optical disc,
Means for storing the relationship between each erase power and the error rate when the erase power is changed;
Means for selecting an erasing power for obtaining the reference error rate based on the relationship between the erasing power and the error rate;
And erasing the data on the optical disc with a selected erasing power. The apparatus according to claim 1,
The optical disk apparatus is characterized in that reproduction is performed with a power smaller than the reproduction power when the reproduction condition is deteriorated. The apparatus according to claim 1,
The optical disc apparatus characterized in that the deterioration of the reproduction condition is a deterioration of reproduction filter characteristics. In the apparatus in any one of Claims 1-4,
The optical disk apparatus according to claim 1, wherein the reference error rate is detected according to each of land recording and groove recording.

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