JP3702824B2 - Optical disk recording device - Google Patents

Description

【００２４】
（ｂ） ４倍速以上の速度倍率で記録するときのボトムパワー値を、１区間内の一部でオフする（ほぼ零にする。）すなわち、例えば図６に示すように、トップパワーでの照射を終了するごとに、ポトムパワー値を一定期間オフする（残りの期間は、形成するピット長やランド長によらずボトムパワー値を一定値とする。）。ボトムパワー値をオフする幅は、記録速度倍率に応じて例えば表２のように切換える（記録速度倍率が高くなるほどボトムパワー値をオフする幅を広くする。）。
【００２５】
【表２】

【００２６】
（ｃ） ４倍速以上の速度倍率で記録するときに、図７に示すように、３Ｔランドを形成する場合にのみボトムパワー値をランドを形成する区間内全体にわたりオフする。４Ｔ以上のランドを形成する場合は、ボトムパワー値を一定とする。
【００２７】
〔Ｂ〕 ９Ｔ，１０Ｔ，１１Ｔのピットを形成する場合のトップパワーの照射時間の補正
９Ｔ，１０Ｔ，１１Ｔのピットを形成する場合の補正量α(nT)の値を、
０≦α(nT)≦０．１５Ｔ
に設定する（なお、このときα(8T)＝０に設定する。）。この補正は、記録速度倍率や線速度によらず常に行う。補正量α(nT)の値は、例えば１０Ｔの場合はα（１０Ｔ）＝０．０６Ｔ，１１Ｔの場合はα（１１Ｔ）＝０．１２Ｔとする。図８は、９Ｔ，１０Ｔ，１１Ｔのピットを形成する時に上記のように補正を行った場合と補正を行わなかった場合（つまり、α(3T)≧α(4T)≧α(5T)≧……≧α(11T),α(3T)＞α(11T) とした場合）のピット長とピットデビエーションの関係の測定結果を示したものである。ピットデビエーションは、規格では許容値が３Ｔのピットが±４０ns以内、１１Ｔのピットが±６０ns以内と定められている。特に１１Ｔのピットデビエーションが許容値を超えると、スピンドル制御が不安定になることがある。補正を行わなかった場合には、９Ｔ，１０Ｔ，１１Ｔが許容値を超えるかあるいは許容値限界近くになるが、補正を行うことにより、９Ｔ，１０Ｔ，１１Ｔとも許容値以内に収まり、スピンドル制御が安定化される。
【００２８】
〔Ｃ〕 記録速度倍率および線速度によるＫ値の補正
Ｋ値とパラメータβ（％）（再生波形のアシンメトリに関連して規格化されているパラメータで、前記記録パラメータにおける補正量β(mT)とは別のパラメータ）との関係を調べてみると、再生波形に歪が現れるときのβ（％）値、ランドジッタが悪化するときのβ（％）値、エラーレートが悪化する時のβ（％）は記録速度倍率に応じて図９に示すように変化する。図９によれば、パワーマージンが最大幅となる時のＫ値は記録速度倍率が高くなるほど小さくなる（４倍速時はＫ＝０．４〜０．５、６倍速時はＫ＝０．２〜０．３あたりで最大パワーマージン幅が得られる。）ことがわかる。また、同じ記録速度倍率のもとでは、パワーマージン幅が最大となる時のＫ値は、線速度が高くなるほど小さくなる。そこで、記録ストラテジー中の定数Ｋの値を記録速度倍率が高くなるほどまた線速度が高くなるほど小さくする。
【００２９】
具体例として、線速度の全範囲（１．２〜１．４ｍ／秒）をある線速度値Ｖ（例えばＶ＝１．２８ｍ／秒）で２つに分け、ディスクをこの値Ｖを境に２つのグループに分け、Ｋ値を表３のように設定する。但し、Ｋ値は、低速グループ＞高速グループとする。
【００３０】
【表３】

これにより、４倍速以上の高速記録時のジッタの悪化やエラーレートの増大が防止される。
【００３１】
また、記録速度倍率によらずＫ値を一定とした場合には、記録速度倍率が高くなるにつれて記録用レーザ光のトップパワー値を大きくしなければならず、高価な高出力レーザダイオードが必要になるのに対し、上記のように記録速度倍率に応じてＫ値を変えるようにすれば、それほど大きなトップパワー値は必要でなくなり、安価な低出力レーザダイオードを使用することができる。
【００３２】
〔Ｄ〕シアニン系ディスクに記録する場合の補正
シアニン系ディスクに４倍速で記録する場合は、記録ストラテジーのα(nT)，β(mT)の値を表４の範囲内の値に設定する。なお、図１０に示すように、α(nTP) はトップパワーの終了位置に付加する（すなわち照射時間の終了を遅らせる）ものであり、β(mTL) はトップパワーの開始位置に付加する（すなわち照射時間の開始を遅らせる）ものである。
【００３３】
【表４】

【００３４】
また、上記照射時間の補正とともに、図１０に示すように、各ピットを形成するトップパワーの照射開始当初に、ほぼ１．５Ｔの時間トップパワーを１ｍＷ増大させる補正を加える。図１１，図１２は、α(nTP) ，β(mTL) を次のように設定した場合のランドジッタとピットデビエーションの測定結果である。尚、図１１、図１２はあるメーカーの線速度１．２１ｍ／秒のディスクに記録ストラテジー（ｎ−０．５）Ｔ＋α(nT)−β(nT)を用いて４倍速で記録した場合である。
【００３５】

【００３６】
図１１，図１２によれば、α(nT)が適性値より大きい場合である（III)は、ピットデビエーションが悪化し、ランドジッタの変化も早い（パラメータβ（％）が浅いところから大きく変化する。）。これに対し、α(nT)が適性値の範囲内にある場合である（Ｉ）は、ピットデビエーションは許容範囲内であり、ランドジッタの値は小さくその変化も小さい。なお、（II）は適性値の範囲内であるが、適正値の範囲の下限値であり、（Ｉ）に比べると再生信号品位は低くなる。
【００３７】
〔Ｅ〕 フタロシアニン系のディスクに記録する場合の補正
フタロシアニン系ディスクに、シアニン系ディスクに記録する場合と同じ照射時間とトップパワー値の補正（図１０）を加えて記録すると、図１３に線Ａで示すようにビットデビエーションが許容値を超えてしまう。そこで、α(nT)による補正とトップパワー値の補正のうちの一方のみを行う。図１３の線Ｂは、α(nT)の補正のみ行った場合、線Ｃはトップパワー値の補正のみ行った場合で、いずれもピットデビエーションは許容範囲内に入っている。
〔光ディスク記録装置の製造方法の実施の形態〕
同一機種の光ヘッドでも半導体レーザのレーザ波長にはばらつきがある（例えば、７７７〜７９４nm）。そこで、光ディスク記録装置の製造時に、予め個々の光ヘッドについてレーザ波長λを測定し、レーザ波長の範囲を例えばλ≦７８３nm、７８３nm＜λ≦７８９nm、７８９nm＜λの３つの範囲に分けて、各光ヘッドのレーザ波長がいずれの範囲に入るかを判定し、その判定結果に応じて表５の記録ストラテジーを適用する。
【００３８】
【表５】

【００３９】
つまり、波長歪の現れやすい波長の短いものは、Ｋ値を大き目にして、トップパワーの時間を短くすることで、波形歪を防ぐ。トップパワーの時間を短くしても、短い波長に対しては感度がよいので、所定のピット長に形成できる。また、波形歪の現れにくい波長の長いものは、感度が悪いので、Ｋ値を小さ目にして所定のピット長が形成されるようにする。６倍速以上用の光ヘッドについても同様にレーザ波長に応じてＫ値を変更する。
【００４０】
適用する記録ストラテジーが決まったら、その記録ストラテジーを該当する光ディスク記録装置内のＥＰ−ＲＯＭに転送して焼きつける。これにより、記録時に、機器ごとに定められた適正な記録ストラテジーが使用される。
【図面の簡単な説明】
【図１】 図４のシステムコントローラによる記録制御の制御ブロック図である。
【図２】 記録用レーザ光の波形図である。
【図３】 （ｎ−Ｋ）Ｔ＋α(nT)ストラテジーを使って高速記録を行った場合の記録パワーに対するエラーレートの変化を示す線図である。
【図４】 この発明の光ディスク記録装置の実施の形態を示すブロック図である。
【図５】 ボトムパワーの補正方法の一例を示す波形図である。
【図６】 ボトムパワーの補正方法の他の例を示す波形図である。
【図７】 ボトムパワーの補正方法の他の例を示す波形図である。
【図８】 １０Ｔ，１１Ｔのピット長に補正を加えた場合と補正を加えない場合のピットデビエーションの違いを示す線図である。
【図９】 記録速度倍率と最大パワーマージンが得られる時の記録ストラテジーのＫ値の変化を説明する特性図である。
【図１０】 シアニン系ディスクに記録する場合の記録ストラテジーの補正内容を説明する波形図である。
【図１１】 シアニン系ディスクに記録する場合に適正な補正を加えた場合と、不適正な補正を加えた場合のランドジッタの変化を示す線図である。
【図１２】 シアニン系ディスクに記録する場合に適正な補正を加えた場合と、不適正な補正を加えた場合のピットデビエーションの変化を示す線図である。
【図１３】 フタロシアニン系ディスクに記録する場合に、照射時間の補正とトップパワーの補正の両方を加えた場合と、いずれか一方のみ加えた場合のピットデビエーションの違いを示す線図である。
【符号の説明】
１…光ディスク記録再生装置、１１…レーザ光[0001]
[Industrial application fields]
The present invention relates to a mark length recording type optical disk recording apparatus that records information by irradiating a recording surface of an optical disk with a laser beam to form a pit, and is four times as fast as a standard speed (= 1 × speed). ) When the high speed recording is performed at the above speed, the deterioration of the recording signal quality (jitter, deviation, error rate, etc.) is prevented.
[0002]
[Prior art]
As one of recording methods for writable optical discs, there is a CD-WO (CD Write Once) standard. In the CD-WO standard, information is 3T to 11T (1T is 1 / 4.218 MHz = 231 ns at 1 × speed, 1/2 at 1 × speed at 2 × speed, 1/4 at 1 × speed at 4 × speed, When the speed is 6 ×, the recording is performed on the optical disc with a combination of 1/6 pits and lands (parts between the pits) of 1 × speed. As shown in FIG. 2, the beam power of the recording laser beam on the CD-WO disk is set to the top power in the section where the pits are formed, and is set to the bottom power in the section where the lands are formed. In this case, if the pit is formed while maintaining the top power for the length of the pit, the pit is actually formed longer by about 1T due to the residual heat of the laser beam. Therefore, the so-called (n−K) T + α (nT) strategy is called, and the duration of the top power is shortened by about KT from the pit length nT to be formed, and pit formation is performed. . Α (nT) is the fine adjustment amount for each pit length.
α (3T) ≧ α (4T) ≧ α (5T) ≧ …… ≧ α (11T) (α (3T)> α (11T))
It is.
[0003]
[Problems to be solved by the invention]
When high-speed recording at 4 × speed or higher is performed using the (n−K) T + α (nT) strategy (in this case, the value of α (nT) is 1/4 of that at 1 × speed). As shown, the error increases abruptly at a certain recording power (top power). In addition, land jitter also deteriorates rapidly. For this reason, it was difficult to set the recording power. Errors and land jitter were also affected by the linear velocity of the disk (1.2 to 1.4 m / s). In addition, since the pit lengths of 9T, 10T, and 11T are shorter than the prescribed values, a trouble has occurred during reproduction on a specific CD player or CD-ROM player. In addition, since a large amount of recording power is required at the time of high-speed recording at a quadruple speed or higher, a high-power laser diode is required, leading to an increase in cost.
[0004]
Even in the same type of optical head, the laser wavelength varies due to variations in semiconductor lasers. In general, since waveform distortion is caused by excessive heat inflow to the dye, waveform distortion is more likely to occur when recording is performed with an optical head having a high recording sensitivity (that is, good heat absorption) and a short laser wavelength. For this reason, even if the same information is recorded by the same type of optical disk recording apparatus equipped with the same type of optical head, the pit formation status varies, resulting in an optical disk recording apparatus with low recording signal quality. In particular, when performing high-speed recording at a quadruple speed or higher, laser light with a short wavelength with good recording sensitivity is used, so slight variations in laser wavelength have caused a reduction in signal quality.
[0005]
An object of the present invention is to provide an optical disk recording apparatus that solves the problems in the prior art and prevents deterioration in recording signal quality when high-speed recording is performed at a speed of 4 × or higher.
[0006]
[Means for Solving the Problems]
In high-speed recording, the error suddenly increases with a certain recording power as shown in FIG. 3 due to the influence of waveform distortion in high-speed recording. In order to prevent this, it is necessary to prevent the inflow of heat from the rear pit. Therefore, in the present invention, when performing high-speed recording, the bottom power value is reduced to almost zero in a part of the section forming each land (the remaining part of the section is set to a constant value other than substantially zero). , Trying to prevent heat from entering from the back pit. In the present invention, the width for turning off the bottom power value is increased as the recording speed magnification is increased. When performing high-speed recording, the bottom power value of the 3T land that particularly affects waveform distortion is reduced to almost zero throughout the section (land other than 3T is set to a constant value other than substantially zero throughout the section). Thus, the inflow of heat from the rear pit can be prevented. Further, by lowering the bottom power value as the recording speed magnification increases, it is possible to prevent heat from flowing in from the rear pit.
[0007]
In addition, the value of α (nT) of the recording strategy when 3T to 8T pits are formed is set to α (3T) ≧ α (4T) ≧ α (5T) ≧ …… ≧ α (8T) (α (3T)> α (8T))
When the pits of 9T to 11T are formed, the value of α (nT) is 0 ≦ α (nT) ≦ 0.15T
By setting to, the pit lengths of 9T, 10T, and 11T can be prevented from being formed short.
[0008]
Further, by decreasing the value of the recording strategy constant K as the recording speed magnification increases and the linear velocity of the disk increases, it is possible to prevent the deterioration of jitter and the increase in error rate.
[0009]
In addition, when recording on a cyanine disk at a quadruple speed, the recording strategy is set to (n−K) T + α (nT) −β (mT), and the value of α (nT) is formed as a 3T pit. If it does, set it to 0.05-0.14T, delay the end of the irradiation time of the top power by that amount, and if it forms 4T pits, set it to 0-0.07T, and increase the amount of top power accordingly Delay the end of the irradiation time, and set the value of β (mT) to 0.12 to 0.2T when forming a land of 3T, and delay the start of the irradiation time of the top power by that amount, Is set to 0.05 to 0.13 T, and the start time of the top power irradiation is delayed by that amount, and when 5 T land is formed, it is set to 0 to 0.07 T and the top is accordingly increased. A correction that delays the start of the power irradiation time and each pit At the beginning of irradiation of the top power to be formed, by adding a correction for increasing the top power by about 1 mW for about 1.5 T, jitter and pit deviation (pit deviation: normal) when recording on a cyanine disc at a quadruple speed Deterioration (increase) in the amount of deviation from the pit length) can be prevented.
[0010]
In addition, when recording on a phthalocyanine-based disk at 4 × speed, the recording strategy is set to (n−K) T + α (nT) −β (mT), and the value of α (nT) is formed as a 3T pit. If it does, set it to 0.05-0.14T, delay the end of the irradiation time of the top power by that amount, and if it forms 4T pits, set it to 0-0.07T, and increase the amount of top power accordingly Delay the end of the irradiation time, and set the value of β (mT) to 0.12 to 0.2T when forming a land of 3T, and delay the start of the irradiation time of the top power by that amount, Is set to 0.05 to 0.13 T, and the start time of the top power irradiation is delayed by that amount, and when 5 T land is formed, it is set to 0 to 0.07 T and the top is accordingly increased. Add a correction to delay the start of the power irradiation time, or In addition to the correction of α (nT) in the correction of the irradiation time of the top power, the correction for increasing the top power by approximately 1 mW for a time of approximately 1.5 T is applied at the beginning of irradiation of the top power for forming each pit. Therefore, it is possible to prevent deterioration of jitter and pit deviation when recording on a phthalocyanine disk at a quadruple speed.
[0011]
In addition, control information relating to the laser modulation method at the time of recording is determined and stored in advance for each wavelength range of the laser light to be used, and the wavelength of the laser light emitted for each semiconductor laser mounted on the optical disk recording apparatus or mounted is determined. Measure, determine which of the wavelength ranges the measured wavelength falls into, and incorporate the control information corresponding to the determined wavelength range into a memory in the optical disc recording apparatus so that it is used during recording By doing so, it is possible to prevent the degradation of the recording signal quality due to the variation of the laser wavelength of the semiconductor laser.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below. FIG. 4 shows a system configuration of the optical disc recording / reproducing apparatus 1 to which the present invention is applied. In the input device 28, the recording speed magnification is set by an operator's operation or the like. In response to a command from the system controller 19, the disk servo circuit 16 keeps the disk motor 12 at a set recording speed magnification constant linear speed (1.2 m / s to 1.4 m / s at 1 × speed and 1 at 2 × speed). Rotation is controlled at double speed at double speed and at quadruple speed at quadruple speed at single speed. In the case of the CD-WO standard, this constant linear velocity control is specified so that the pregroup wobble is 22.05 kHz. Therefore, the wobble is detected from the output signal of the optical head 13 (tracking error). The disc motor 12 can be detected from a residual signal) at a predetermined frequency (22.05 kHz at 1 × speed, 44.1 kHz at 2 × speed, 88.2 kHz at 4 × speed,...). This is realized by performing PLL control.
[0013]
The focus servo and tracking servo circuit 18 controls the focus and tracking of the laser beam 11 emitted from the semiconductor laser in the optical head 13 according to a command from the system controller 19. Tracking control is performed by detecting pregrooves formed on the disk 10. The feed servo circuit 17 drives the feed motor 20 according to a command from the system controller 19 to move the optical head 13 in the radial direction of the disk 10.
[0014]
An input signal to be recorded on the optical disk 10 (CD-WO disk) is directly input to the data signal forming circuit 22 in the case of a digital signal at a speed corresponding to the recording speed magnification, and in the case of an analog signal, the A / D converter 24. And input to the recording signal forming circuit 22. The recording signal forming circuit 22 interleaves the input data, adds an error check code, adds TOC information and subcode information generated by the TOC and subcode generation circuit 23, performs EFM modulation, and performs CD standards. A series of serial data is formed at a transfer rate corresponding to the format and the recording speed magnification, and output as a recording signal.
[0015]
This recording signal is modulated by the recording signal correction circuit 26 (irradiation control means) via the drive interface 15 according to the recording strategy selected according to the disc type (dye material type), linear velocity, recording velocity magnification, etc. To the laser generation circuit 25. The laser generating circuit 25 drives the semiconductor laser in the optical head 13 in accordance with the recording signal, irradiates the recording surface of the optical disk 10 with the laser beam, forms pits, and performs recording. The laser power at this time is commanded to a value corresponding to the recording speed magnification and the linear velocity as required, and is controlled to this commanded power with high accuracy by an ALPC (Automatic Laser Power Control) circuit. As a result, data is recorded on the optical disc 10 at the CD standard format, transfer rate, and linear velocity (1.2 to 1.4 m / s).
[0016]
When the optical disk 10 recorded as described above is reproduced by irradiating it with a reproduction laser beam (with a smaller power than the recording laser beam), the read data is demodulated by the signal reproduction processing circuit 30 as it is as a digital signal, or as a D / D signal. The analog signal is converted by the A converter 32 and output.
[0017]
FIG. 1 shows a control block for recording control by the system controller 19 of FIG. The recording speed magnification setting means 28 corresponds to the input device 28 in FIG. 4 and sets the recording speed magnification (× 1, × 2, × 4,...) By the operation of the operator. The disc type and linear velocity discriminating means 32 discriminates the disc type and linear velocity of the optical disc 10 set in the apparatus. The disc type can be determined using information indicating the disc type among disc IDs recorded in advance on the optical disc 10, for example. For example, the linear velocity is read from the recording time (63-minute type, 74-minute type, or other intermediate type) recorded in the ATIP signal in the lead-in portion of the disk, and the corresponding linear velocity is discriminated (63 minutes). (The type is 1.4 m / s, the 74 minute type is 1.2 m / s), and can be calculated from the encoder output of the spindle motor.
[0018]
The recording strategy storage means 34 stores an optimal recording strategy (time modulation amount, recording power, etc.) in accordance with the combination of the disc type, linear velocity, and recording velocity magnification. The recording strategy selection means 36 reads the corresponding recording strategy from the recording strategy storage means 34 in accordance with the input disc type, linear velocity, and recording speed magnification information. The control means 38 controls the recording signal correction circuit 26 in accordance with the read recording strategy, and modulates the length of the pit formation portion or blank formation portion of the recording signal. Further, the laser power is controlled by controlling the laser generation circuit 25. Further, the disk servo circuit 16 is controlled to control the rotation of the disk motor 12 at a speed corresponding to the commanded recording speed magnification.
[0019]
The specific contents of the recording laser light irradiation time and recording power by the control means 38 of FIG. 1 will be described. The control means 38 sets the beam power of the recording laser beam to the top power at which the pit is formed in the section where the pit is formed, and the pit is formed in the section where the land is formed after the pit is formed until the next pit is formed. Is set to the bottom power at which no is formed, and the irradiation time of the top power is set to the pit length nT (n = 3, 4,..., 11) to be formed and the land length mT immediately before that (m = 3,4,... , 11) according to the recording strategy (n−K) T + α (nT) −β (mT)
However, K: constant α (nT): correction amount for each pit length, at least α (3T) ≧ α (4T) ≧ α (5T) ≧ …… ≧ α (8T) (α (3T)> α ( 8T))
β (mT): Correction amount for each land length immediately before, at least β (3T) ≧ β (4T) ≧ β (5T) ≧ …… ≧ β (8T) (β (3T)> β (8T))
The recording laser beam is irradiated on the recording surface of the dye-based optical disc 10 to form 3T to 11T pits and lands. At the time of 1 × speed recording, pits and lands are formed according to the recording pulse waveform as shown in FIG. 2 according to this recording strategy.
[0020]
Further, according to the recording speed magnification, pit formation is performed by adding the following correction or parameter value setting to the recording strategy.
[0021]
[A] Correction of bottom power When high-speed recording at a speed of 4 × or higher is performed using the above recording strategy, an error rapidly increases at a certain recording power (top power value). In order to prevent this, it is necessary to prevent the inflow of heat from the rear pit. Therefore, any one of the following corrections (a), (b), and (c) is added to the bottom power value.
[0022]
(A) The bottom power value is lowered as the recording speed magnification is increased. That is, as shown in FIG. 5, the bottom power value is set to a constant value regardless of the pit length or land length to be formed and increased or decreased according to the recording speed magnification as shown in the following equation.
Bottom power value (V1) ≤ Bottom power value (V2)
However, V1 and V2 are recording speed magnifications and V1> V2.
Specific examples of the bottom power value are shown in Table 1.
[0023]
[Table 1]

[0024]
(B) The bottom power value when recording at a speed magnification of 4 × speed or more is turned off in a part of one section (substantially set to zero). That is, for example, irradiation with top power as shown in FIG. Each time, the potom power value is turned off for a certain period (the bottom power value is set to a constant value for the remaining period regardless of the pit length and land length to be formed). The width for turning off the bottom power value is switched, for example, as shown in Table 2 in accordance with the recording speed magnification (the higher the recording speed magnification, the wider the width for turning off the bottom power value).
[0025]
[Table 2]

[0026]
(C) When recording at a speed magnification of 4 × speed or more, as shown in FIG. 7, the bottom power value is turned off over the entire section in which the land is formed only when the 3T land is formed. When forming a land of 4T or more, the bottom power value is constant.
[0027]
[B] Correction of irradiation time of top power when forming pits of 9T, 10T, and 11T The value of the correction amount α (nT) when forming pits of 9T, 10T, and 11T,
0 ≦ α (nT) ≦ 0.15T
(In this case, α (8T) = 0 is set). This correction is always performed regardless of the recording speed magnification or linear velocity. The value of the correction amount α (nT) is, for example, α (10T) = 0.06T in the case of 10T, and α (11T) = 0.12T in the case of 11T. FIG. 8 shows a case where correction is performed as described above when forming 9T, 10T, and 11T pits, and a case where correction is not performed (that is, α (3T) ≧ α (4T) ≧ α (5T) ≧. .... gtoreq..alpha. (11T), .alpha. (3T)>. Alpha. (11T)) showing the measurement results of the relationship between the pit length and the pit deviation. The pit deviation is defined in the standard as an allowable value of 3T pits within ± 40 ns and 11T pits within ± 60 ns. In particular, if the 11T pit deviation exceeds an allowable value, the spindle control may become unstable. If no correction is performed, 9T, 10T, and 11T exceed the allowable value or are close to the allowable value limit. However, by performing the correction, both 9T, 10T, and 11T are within the allowable value, and the spindle control is performed. Stabilized.
[0028]
[C] Correction of K value by recording speed magnification and linear velocity K and parameter β (%) (a parameter that is standardized in relation to the asymmetry of the reproduction waveform, and the correction amount β (mT) in the recording parameter and Is another parameter), the β (%) value when distortion appears in the reproduced waveform, the β (%) value when the land jitter deteriorates, and the β (% when the error rate deteriorates) %) Changes as shown in FIG. 9 according to the recording speed magnification. According to FIG. 9, the K value when the power margin becomes the maximum width decreases as the recording speed magnification increases (K = 0.4 to 0.5 at 4 × speed, K = 0.2 at 6 × speed). It can be seen that the maximum power margin width is obtained around .about.0.3). Further, under the same recording speed magnification, the K value when the power margin width is maximized becomes smaller as the linear velocity becomes higher. Therefore, the value of the constant K in the recording strategy is decreased as the recording speed magnification is increased and the linear velocity is increased.
[0029]
As a specific example, the entire range (1.2 to 1.4 m / sec) of the linear velocity is divided into two by a certain linear velocity value V (for example, V = 1.28 m / sec), and the disk is divided by this value V as a boundary. Dividing into two groups, K values are set as shown in Table 3. However, the K value is set to low speed group> high speed group.
[0030]
[Table 3]

As a result, deterioration of jitter and increase in error rate during high-speed recording at 4 × speed or higher are prevented.
[0031]
If the K value is constant regardless of the recording speed magnification, the top power value of the recording laser beam must be increased as the recording speed magnification increases, and an expensive high-power laser diode is required. On the other hand, if the K value is changed according to the recording speed magnification as described above, a very large top power value is not necessary, and an inexpensive low-power laser diode can be used.
[0032]
[D] Correction when recording on cyanine disk When recording at 4 times speed on a cyanine disk, the values of α (nT) and β (mT) of the recording strategy are set to values within the range shown in Table 4. As shown in FIG. 10, α (nTP) is added to the end position of the top power (that is, delays the end of the irradiation time), and β (mTL) is added to the start position of the top power (that is, The start of the irradiation time is delayed).
[0033]
[Table 4]

[0034]
Further, along with the correction of the irradiation time, as shown in FIG. 10, at the beginning of the irradiation of the top power for forming each pit, a correction for increasing the time top power of about 1.5 T by 1 mW is added. FIGS. 11 and 12 show the measurement results of land jitter and pit deviation when α (nTP) and β (mTL) are set as follows. 11 and 12 show a case where recording is performed at a quadruple speed using a recording strategy (n−0.5) T + α (nT) −β (nT) on a disk of a certain manufacturer with a linear velocity of 1.21 m / sec. .
[0035]

[0036]
According to FIGS. 11 and 12, when (α) is larger than the appropriate value (III), the pit deviation is deteriorated and the land jitter is rapidly changed (the parameter β (%) is greatly changed from a shallow value). To do.) On the other hand, in the case (I) where α (nT) is within the range of the appropriate value, the pit deviation is within the allowable range, the value of the land jitter is small, and the change thereof is small. Although (II) is within the range of the appropriate value, it is a lower limit value of the appropriate value range, and the reproduction signal quality is lower than that of (I).
[0037]
[E] Correction when recording on a phthalocyanine disc When recording is performed with the same irradiation time and top power value correction (FIG. 10) as that when recording on a cyanine disc added to a phthalocyanine disc, a line A in FIG. As shown by, the bit deviation exceeds the allowable value. Therefore, only one of the correction by α (nT) and the correction of the top power value is performed. The line B in FIG. 13 shows the case where only the correction of α (nT) is performed, and the line C shows the case where only the correction of the top power value is performed. In both cases, the pit deviation is within the allowable range.
[Embodiment of Manufacturing Method of Optical Disc Recording Apparatus]
Even in the optical head of the same model, the laser wavelength of the semiconductor laser varies (for example, 777 to 794 nm). Therefore, when the optical disk recording apparatus is manufactured, the laser wavelength λ is measured in advance for each optical head, and the range of the laser wavelength is divided into, for example, three ranges of λ ≦ 783 nm, 783 nm <λ ≦ 789 nm, and 789 nm <λ. It is determined in which range the laser wavelength of the optical head falls, and the recording strategy shown in Table 5 is applied according to the determination result.
[0038]
[Table 5]

[0039]
That is, for those having a short wavelength in which wavelength distortion is likely to appear, waveform distortion is prevented by increasing the K value and shortening the time of top power. Even if the time of the top power is shortened, the sensitivity to the short wavelength is good, so that the pit length can be formed. In addition, a long wavelength with which waveform distortion does not easily occur has low sensitivity, so that a predetermined pit length is formed with a small K value. For the optical head for 6 × speed or higher, the K value is similarly changed according to the laser wavelength.
[0040]
When the recording strategy to be applied is determined, the recording strategy is transferred to the EP-ROM in the corresponding optical disk recording apparatus and burned. Thus, an appropriate recording strategy determined for each device is used during recording.
[Brief description of the drawings]
FIG. 1 is a control block diagram of recording control by a system controller of FIG.
FIG. 2 is a waveform diagram of a recording laser beam.
FIG. 3 is a diagram showing a change in error rate with respect to recording power when high-speed recording is performed using an (n−K) T + α (nT) strategy.
FIG. 4 is a block diagram showing an embodiment of an optical disk recording apparatus of the present invention.
FIG. 5 is a waveform diagram showing an example of a bottom power correction method.
FIG. 6 is a waveform diagram showing another example of a bottom power correction method.
FIG. 7 is a waveform diagram showing another example of a bottom power correction method.
FIG. 8 is a diagram showing the difference in pit deviation between when the pit lengths of 10T and 11T are corrected and when no correction is made.
FIG. 9 is a characteristic diagram for explaining the change in the K value of the recording strategy when the recording speed magnification and the maximum power margin are obtained.
FIG. 10 is a waveform diagram for explaining correction contents of a recording strategy when recording on a cyanine disc.
FIG. 11 is a diagram showing changes in land jitter when an appropriate correction is applied when recording on a cyanine disc and when an inappropriate correction is applied.
FIG. 12 is a diagram showing changes in pit deviations when an appropriate correction is applied when recording on a cyanine disc and when an inappropriate correction is applied.
FIG. 13 is a diagram showing the difference in pit deviation between when both irradiation time correction and top power correction are applied and when only one of them is added when recording on a phthalocyanine disc.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Optical disk recording / reproducing apparatus, 11 ... Laser beam

Claims (1)

Set the beam power of the recording laser light irradiated to the recording surface of the dye-based optical disc to the top power at which pits are formed in the section where pits are formed. In the optical disc recording apparatus that performs the formation of pits and lands by the mark length recording method by setting the bottom power so that pits are not formed in the section to be formed,
The bottom power value when recording at a speed magnification greater than a predetermined value is turned off at a part of the section forming each land, and the width at which the bottom power value is turned off as the recording speed magnification increases (the relative width with respect to T). say.) optical disk recording apparatus characterized by the widening.

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