【０００１】 [0001]

【発明の属する技術分野】本発明は、ＤＶＤ−ＲＡＭ方式のランド・グルーブの様に記録トラックがトラッキング信号を形成し易い深さに形成されている光ディスクを再生する非点収差方式の光ピックアップを有する光ディスク再生装置に関する。 BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an astigmatic optical pickup for reproducing an optical disk having recording tracks formed at a depth where a tracking signal can be easily formed, such as a land / groove of a DVD-RAM system. The present invention relates to an optical disk reproducing device having the same.

【０００２】 [0002]

【従来の技術】一般に、ＤＶＤ−ＲＡＭ盤のような光ディスクは等幅のランドとグルーブの両方に信号を記録する方式であり、深さλ／６でランド、グルーブがその幅０．７４μｍ（２．６ＧＢの場合）、或いは０．６１５μｍ（４．７ＧＢの場合）で形成されたディスク構造である。ここでλは再生レーザ光の波長である。このような構造の光ディスクにフォーカスサーボをかけるて情報を読みとる時、光ディスクの偏芯やアクセス動作で光スポットがトラックを横切ると、ランドやグルーブによる回折現像によって反射光の強度分布パターンが非対称となって、この結果、トラックの進行方向（Ｔａｎ方向）

【０００３】このような状況下において、フォーカス誤差検出方式が非点収差法を採用している光ピックアップの場合には、検出系の調整精度に依存してこのトラックの横切りによる光強度分布の変化が非点収差信号検出の対角和の差分演算で打ち消せなくて、フォーカス誤差信号に溝渡りによる変調成分が漏れ込むＦＥクロストーク（フィードスルー、又は溝横断信号とも言われている）
の問題があった。 There was a problem. また、非点収差法はこの調整精度の影響で反射光のパターンノイズの受け易い検出方式でもあった。 In addition, the non-point aberration method is also a detection method that is susceptible to pattern noise of reflected light due to the influence of this adjustment accuracy. 尚、上記ＦＥとはフォーカスエラーのことを意味する。 The above FE means a focus error. Under such circumstances, in the case of an optical pickup employing a focus error detection method employing an astigmatism method, a change in light intensity distribution due to crossing of the track depends on the adjustment accuracy of the detection system. Is FE crosstalk in which modulation components due to groove crossing leak into the focus error signal because they cannot be canceled by the difference calculation of the diagonal sum of astigmatism signal detection (also referred to as feed-through or groove crossing signal) Is FE crosstalk in which modulation. Is FE crosstalk in which modulation. Under such circumstances, in the case of an optical pickup reagents a focus error detection method investigated an astigmatism method, a change in light intensity distribution due to crossing of the track depends on the adjustment accuracy of the detection system. components due to groove crossing leak into the focus error signal because they cannot be canceled by the difference calculation of the diagonal sum of astigmatism signal detection (also referred to as feed-through or groove crossing signal)
There was a problem. In addition, the astigmatism method is a detection method that is susceptible to pattern noise of reflected light due to the influence of the adjustment accuracy. Note that the above FE means a focus error. There was a problem. In addition, the astigmatism method is a detection method that is susceptible to pattern noise of reflected light due to the influence of the adjustment accuracy. Note that the above FE means a focus error.

【０００４】特に、信号検出用の光検出器（フォトディテクタ）の分割線が反射スポット中心に対して、Ｔａｎ
方向にずれている場合や、光ディスクの複屈折によって、反射光に非点収差が発生する場合には、このＦＥクロストークが大きくなり、フォーカスサーボをかけた状態で検出信号に不要信号が重畳される。 If there is a deviation in the direction or if non-point aberration occurs in the reflected light due to the double refraction of the optical disk, this FE crosstalk becomes large and an unnecessary signal is superimposed on the detection signal with the focus servo applied. To. この状態ではフォーカスサーボ動作で合焦ズレを発生したり、トラック横断によるＡＣ（交流）信号成分がフォーカス駆動系に混入し、面ブレに対して対物レンズを光軸方向に駆動するのに必要な面ブレ周波数帯域の信号以外の成分が混入し、駆動波形が必要なレベルより大きくなり、その周波数成分によっては不要な音を発生したり、更には、ＡＣ In this state, it is necessary to drive the objective lens in the optical axis direction against surface blur due to in-focus shift due to focus servo operation or AC (AC) signal component mixed in the focus drive system due to crossing the track. Components other than the signal in the surface blur frequency band are mixed, and the drive waveform becomes larger than the required level, and depending on the frequency component, unnecessary sound may be generated, and further, AC
成分はそのレベルの実効値とコイル抵抗のかけ算で求められる値の発熱を引き起こすので、温度上昇を起こすなどの問題を発生していた。 Since the component causes heat generation of the value obtained by multiplying the effective value of the level and the coil resistance, problems such as causing a temperature rise have occurred. [0004] In particular, the dividing line of the photodetector (photodetector) for detecting a signal is located at a position closer to the center of the reflection spot than to the Tan. [0004] In particular, the dividing line of the photodetector (photodetector) for detecting a signal is located at a position closer to the center of the reflection spot than to the Tan.
If the direction is shifted in the direction or if astigmatism occurs in the reflected light due to the birefringence of the optical disk, the FE crosstalk increases, and an unnecessary signal is superimposed on the detection signal in a state where the focus servo is applied. You. In this state, a focus shift occurs due to the focus servo operation, or an AC (alternating current) signal component due to track traversal mixes into the focus drive system, and is necessary to drive the objective lens in the optical axis direction against surface shake. A component other than the signal in the surface vibration frequency band is mixed, and the driving waveform becomes larger than a required level, and depending on the frequency component, an unnecessary sound is generated. If the direction is correlated in the direction or if astigmatism occurs in the reflected light due to the birefringence of the optical disk, the FE crosstalk increases, and an unnecessary signal is multiplexed on the detection signal in a state where the focus servo is applied. You. In this state, a focus shift occurs due to the focus servo operation, or an AC (alternating current) signal component due to track traversal mixes into the focus drive system, and is necessary to drive the objective lens in the optical axis direction against surface shake. A component other than the signal in the surface vibration frequency band is mixed, and the driving waveform becomes larger than a required level, and depending on the frequency component, an unnecessary sound is generated.
The component generates heat at a value determined by multiplying the effective value of the level by the coil resistance, and thus causes a problem such as a rise in temperature. The component generates heat at a value determined by multiplying the effective value of the level by the coil resistance, and thus causes a problem such as a rise in temperature.

【０００５】例えば、上記フォーカス信号の溝横断ストロークの発生原因の解析結果の一例が文献 Lissajous analysis of focus crosstalk in optical disk systems （ＳＰＩＥ Ｖｏｌ．１４９９ Ｏｐｔｉｃａｌ Ｄａｔａ Ｓｔｏｒａｇｅ ’９１第３５４頁〜第３５９頁）に示されており、ここでは理想的な光学系とアライメントズレや各種収差発生下でのＰＰ（プッシュプル）

【０００６】 [0006]

【発明が解決しようとする課題】ところで、上記問題点に対して、特開平１０−６４０８０号公報、特開平１０ −６４１０４号公報或いは第６０回応用物理学会等に、その対策案が報告されている。上記特開平１０−６４０
８０号公報では、非点収差法で光検出器がＴａｎ方向に位置ズレしたときに発生する溝横断によるＦＥクロストークをタンジェンシャルプッシュプル信号によって、相殺する方法が述べられている。 Japanese Patent Application Laid-Open No. 80 describes a method of canceling FE crosstalk due to groove crossing generated when the optical detector is displaced in the Tan direction by the non-point aberration method by a tangential push-pull signal. しかしながら、この方法では光検出器のＴａｎ方向のズレによるＦＥクロストーク成分は補正できるが、非点収差によるクロストーク成分は位相が異なるため打ち消せない問題があった。 However, although this method can correct the FE crosstalk component due to the deviation of the optical detector in the Tan direction, there is a problem that the crosstalk component due to non-point aberration cannot be canceled because the phases are different. SUMMARY OF THE INVENTION Incidentally, in order to solve the above problems, Japanese Patent Application Laid-Open Nos. MUST OF THE FIGURE, in order to solve the above problems, Japanese Patent Application Laid-Open Nos.
-64104 or the 60th Japan Society of Applied Physics, etc. -64104 or the 60th Japan Society of Applied Physics, etc.
Measures have been reported. JP-A-10-640 Measures have been reported. JP-A-10-640
No. 80 describes a method of canceling FE crosstalk due to crossing a groove, which occurs when a photodetector is displaced in the Tan direction by an astigmatism method, using a tangential push-pull signal. However, in this method, although the FE crosstalk component due to the deviation of the photodetector in the Tan direction can be corrected, there is a problem that the crosstalk component due to astigmatism cannot be canceled out because the phase is different. No. 80 describes a method of canceling FE crosstalk due to crossing a groove, which occurs when a photodetector is displaced in the Tan direction by an astigmatism method, using a tangential push-pull signal. However, in this method, although the FE crosstalk component due to the deviation of the photodetector in the Tan direction can be corrected, there is a problem that the crosstalk component due to astigmatism cannot be canceled out because the phase is different.

【０００７】また、特開平１０−６４１０４号公報では、１／２トラックピッチずれた２つのスポットを用いて、非点収差法によるフォーカス検出を行うようになっている。そして、フォーカス誤差信号に混入する溝横断信号はピッチ周期の信号であるため、１／２トラックピッチ離れた非点収差信号におけるＦＥクロストーク成分は１／２トラックピッチずれることで半周期の位相差の信号となる。一方、フォーカス誤差信号は同相である。そのため、この２信号を加算すると同相のフォーカス誤差信号は２倍となり、半周期位相差のあるフォーカスクロストーク成分はほぼ逆位相の信号となって相殺する。

【０００８】しかしながら、この方式では、ランドとグルーブの幅が不一致や溝構造が不一致の場合は１／２トラックピッチ離れたところでのＦＥクロストークが必ずしも逆位相とはならないため、ある程度のレベル低下にはなっても完全な打ち消しにはならない場合があった。

【０００９】この場合でもＦＥクロストークが半トラックピッチで対称でない場合は完全な打ち消しはできなくて、ある程度のクロストーク成分の減少だけを図ることができる。この方式では光検出器が１２分割になり、Ｄ

【００１０】本発明は、以上のような問題点に着目し、これを有効に解決すべく創案されたものであり、その目的は、ＦＥクロストークとＰＰ誤差信号の関係をメモリーし、補正波形信号をＴＥ信号から形成し、この補正波形信号とＦＥ信号とを演算することで、ＦＥ信号中のクロストーク成分を相殺するように補正することができる光ディスク再生装置を提供することにある。[0010] The present invention focuses on the above problems,
The purpose of this invention is to solve this problem effectively. The purpose is to memorize the relationship between FE crosstalk and PP error signal, form a correction waveform signal from a TE signal, and convert this correction waveform signal and the FE signal. It is an object of the present invention to provide an optical disc reproducing apparatus capable of performing a calculation to correct the crosstalk component in the FE signal so as to cancel out the crosstalk component. The purpose of this invention is to solve this problem effectively. The purpose is to memorize the relationship between FE crosstalk and PP error signal, form a correction waveform signal from a TE signal, and convert this correction waveform signal and the FE signal. It is an object of the present invention to provide an optical disc reproducing apparatus capable of performing a calculation to correct the crosstalk component in the FE signal so as to cancel out the crosstalk component.

【００１１】 [0011]

【課題を解決するための手段】請求項１に規定する発明は、光ディスクに記録された情報を読み取るため、読み取り用の光スポットを面ぶれに追従して制御するフォーカスサーボ誤差検出に、非点収差方式を採用している光ピックアップを有する光ディスク再生装置において、前記光ディスクに形成されたランドやグルーブを横切る溝横断によってフォーカス誤差に混入するクロストークを抑圧するため、メインスポットのプッシュプル誤差信号とフォーカスクロストークの内、外径方向に横断の１周期分の振幅、位相関係をメモリーし、この関係を約１／

【００１２】 [0012]

【発明の実施の形態】以下に、本発明に係る光ディスク再生装置の一実施例を添付図面に基づいて詳述する。図１は本発明に係る光ディスク再生装置に用いる光ピックアップの一例を示す構成図、図２は光ピックアップからの信号を処理する信号処理系を示すブロック構成図、図３は信号処理系で得られる各信号からフォーカスエラー（ＦＥ）信号を補正する補正制御系を示すブロック構成図である。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an optical disk reproducing apparatus according to the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a block diagram showing an example of an optical pickup used in an optical disk reproducing apparatus according to the present invention, FIG. 2 is a block diagram showing a signal processing system for processing a signal from the optical pickup, and FIG. 3 is obtained by the signal processing system. FIG. 3 is a block diagram illustrating a correction control system that corrects a focus error (FE) signal from each signal.

【００１３】図１において、この光ピックアップ２は、その検出方式において、トラッキング検出にＤＰＰ方式を使用し、フォーカス検出に非点収差法を使用した光学系となっている。図中、ＬＤは再生用のレーザ光Ｌを出力するレーザ素子、４はレーザ光Ｌから３つの光束を得るためのグレーティング、６は偏光ビームスプリッタ、８はレーザ光Ｌを平行光束にするコリメータレンズ、１０はλ／４板、１２は光ディスク１４上にレーザ光Ｌを集束させる対物レンズ、１６はシリンドリカルレンズ、１８は光ディスク１４からの反射光を検出する光検出素子等よりなる光検出器である。この光検出器１８は、

【００１４】上記光検出器１８から得られる信号の処理系は図２に示されている。図中、２０、２２、２４、２ ６は減算器、３０、３２、３４、３６、３８、４０は加算器、４２はゲインＫを与える増幅器である。また、４
４はＦＥｍ信号から補正ＦＥ信号を形成する本発明の特徴とする補正制御系４４である。 Reference numeral 4 denotes a correction control system 44, which is a feature of the present invention and forms a correction FE signal from the FEm signal. 従って、図中の各信号は以下のように表される。 Therefore, each signal in the figure is represented as follows. ＴＥｓ＝Ｅ１＋Ｆ１−（Ｅ２＋Ｆ２） ＴＥｍ＝（Ａ＋Ｄ）−（Ｂ＋Ｃ） ＦＥｍ＝（Ａ＋Ｃ）−（Ｂ＋Ｄ） ＳＵＭｓ＝Ｅ１＋Ｆ１＋Ｅ２＋Ｆ２ ＳＵＭｍ＝Ａ＋Ｂ＋Ｃ＋Ｄ ＤＰＰ＝（Ａ＋Ｄ）−（Ｂ＋Ｃ）−Ｋ×｛（Ｅ１＋Ｆ TEs = E1 + F1- (E2 + F2) TEm = (A + D)-(B + C) Fem = (A + C)-(B + D) SUMs = E1 + F1 + E2 + F2 SUMm = A + B + C + D DPP = (A + D)-(B + C) -Kx
１）−（Ｅ２＋Ｆ２）｝ FIG. 2 shows a processing system for a signal obtained from the photodetector 18. In the figure, 20, 22, 24, 2 1)-(E2 + F2)} FIG. 2 shows a processing system for a signal obtained from the photodetector 18. In the figure, 20, 22, 24, 2
6 is a subtractor, 30, 32, 34, 36, 38 and 40 are adders, and 42 is an amplifier for giving a gain K. Also, 4 6 is a subtractor, 30, 32, 34, 36, 38 and 40 are adders, and 42 is an amplifier for giving a gain K. Also, 4
Reference numeral 4 denotes a correction control system 44 for forming a correction FE signal from the FEm signal, which is a feature of the present invention. Therefore, each signal in the figure is represented as follows. TEs = E1 + F1− (E2 + F2) TEm = (A + D) − (B + C) FEm = (A + C) − (B + D) SUMs = E1 + F1 + E2 + F2 SUMm = A + B + C + D DPP = (A + D) − (B + C) −K × ｛ Reference numeral 4 Then a correction control system 44 for forming a correction FE signal from the FEm signal, which is a feature of the present invention. Therefore, each signal in the figure is represented as follows. TEs = E1 + F1− (E2 + F2) TEm = (A + D) − (B + C) FEm = (A + C) − (B + D) SUMs = E1 + F1 + E2 + F2 SUMm = A + B + C + D DPP = (A + D) − (B + C) −K × {
1)-(E2 + F2)｝ 1)-(E2 + F2)}

【００１５】さて、図１及び図２に示すように構成された光ピックアップ及び信号処理系において、レーザ素子ＬＤから出射されたレーザ光Ｌはグレーティング４で３
つの光束を形成し、偏光ビームスプリッタ６を経てコリメータレンズ８で平行光に変換後、対物レンズ１２に入射されて、光ディスク１４面上に３ビームの光スポットを形成する。 Two light beams are formed, converted into parallel light by the collimator lens 8 through the polarizing beam splitter 6, and then incident on the objective lens 12 to form a three-beam light spot on the 14th surface of the optical disk. ３つの光スポットはトラック進行方向（Ｔ The three light spots are in the direction of travel of the truck (T
ａｎ方向）で２０μｍ位の間隔であり、またラジアル方向（ディスク半径方向）では１／２トラックピッチ離れて盤面に形成される。 It is formed on the board surface at intervals of about 20 μm in the an direction) and 1/2 track pitch in the radial direction (disc radial direction). 光ディスク１４がＤＶＤ−ＲＡＭ The optical disk 14 is a DVD-RAM
第一世代とＤＶＤ−ＲＷ盤のトラックピッチは０．７４ The track pitch of the first generation and DVD-RW board is 0.74
μｍであるがＲＡＭ第二世代４．７ＧＢは０．６１５μ Although it is μm, RAM 2nd generation 4.7GB is 0.615μ
ｍであり、共用のときは０．７４μｍを基本に配置されるものとする。 It is m, and when shared, it shall be basically arranged at 0.74 μm. 光ディスク１４から反射された光束は復路の光学系を通過して、コリメータレンズ８とシリンドリカルレンズ１６による非点収差検出系で非点収差を光束に与えて光検出器１８の各セグメント１８Ａ、１８ The light beam reflected from the optical disk 14 passes through the optical system on the return path, and the non-point aberration detection system by the collimator lens 8 and the cylindrical lens 16 gives the light beam non-point aberration to each segment 18A, 18 of the light detector 18.
Ｂ、１８Ｃ上にそれぞれ対応する光スポットを形成し、 Corresponding light spots are formed on B and 18C, respectively.
各光強度に応じた信号が形成される。 A signal corresponding to each light intensity is formed. In the optical pickup and signal processing system configured as shown in FIGS. 1 and 2, the laser light L emitted from the laser In the optical pickup and signal processing system configured as shown in FIGS. 1 and 2, the laser light L emitted from the laser
After forming two light beams, the light beams are converted into parallel light by the collimator lens 8 through the polarizing beam splitter 6, and then are incident on the objective lens 12 to form a light spot of three beams on the surface of the optical disk 14. The three light spots are in the track traveling direction (T After forming two light beams, the light beams are converted into parallel light by the collimator lens 8 through the waveguide beam splitter 6, and then are incident on the objective lens 12 to form a light spot of three beams on the surface of the optical disk 14. The three light spots are in the track traveling direction (T
In the radial direction (disc radial direction), they are formed on the board at a distance of 1/2 track pitch in the radial direction (disc radial direction). Optical disc 14 is DVD-RAM In the radial direction (disc radial direction), they are formed on the board at a distance of 1/2 track pitch in the radial direction (disc radial direction). Optical disc 14 is DVD-RAM
Track pitch of the first generation and DVD-RW board is 0.74 Track pitch of the first generation and DVD-RW board is 0.74
μm, but the second generation of 4.7GB RAM is 0.615μ μm, but the second generation of 4.7GB RAM is 0.615μ
m and 0.74 μm when shared. The light beam reflected from the optical disk 14 passes through the return optical system, and astigmatism is given to the light beam by the astigmatism detection system including the collimator lens 8 and the cylindrical lens 16, and the segments 18 A, 18 of the photodetector 18 are provided. m and 0.74 μm when shared. The light beam reflected from the optical disk 14 passes through the return optical system, and astigmatism is given to the light beam by the astigmatism detection system including the collimator lens 8 and the cylindrical lens 16, and the segments 18 A, 18 of the photodetector 18 are provided.
B, forming corresponding light spots respectively on 18C, B, forming corresponding light spots respectively on 18C,
A signal corresponding to each light intensity is formed. A signal corresponding to each light intensity is formed.

【００１６】ここで、前述のようにメインスポットは４
分割セグメント１８Ａで検出され、２つのサブスポットがそれぞれ２分割のセグメントＥ１、Ｅ２及びＦ１、Ｆ Detected in split segment 18A, the two subspots are split into two segments E1, E2 and F1, F respectively.
２で検出される。 Detected in 2. メインスポットでＳＵＭｍ（ＲＦ）信号、トラッキング信号ＴＥｍ、フォーカス誤差信号ＦＥ SUMm (RF) signal, tracking signal TEm, focus error signal FE at the main spot
ｍは以下の演算で形成される。 m is formed by the following calculation. ＳＵＭｍ＝Ａ＋Ｂ＋Ｃ＋Ｄ ＦＥｍ＝（Ａ＋Ｃ）−（Ｂ＋Ｄ） ＴＥｍ＝（Ａ＋Ｄ）−（Ｂ＋Ｃ） ＤＰＰ信号はＴＥｍにサブスポットのＰＰ信号であるＴ SUMm = A + B + C + D FEm = (A + C)-(B + D) TEm = (A + D)-(B + C) DPP signal is a sub-spot PP signal in TEm T
Ｅｓ信号にスポット強度比Ｋのゲイン調整をして加えられる。 It is added to the Es signal after adjusting the gain of the spot intensity ratio K. ＤＰＰ＝（Ａ＋Ｄ）−（Ｂ＋Ｃ）−Ｋ×｛（Ｅ１＋Ｆ DPP = (A + D)-(B + C) -K × {(E1 + F)
１）−（Ｅ２＋Ｆ２）｝ Here, the main spot is 4 as described above. 1)-(E2 + F2)} Here, the main spot is 4 as described above.
The two sub-spots detected in the segment 18A are divided into two segments E1, E2 and F1, F, respectively. The two sub-spots detected in the segment 18A are divided into two segments E1, E2 and F1, F, respectively.
2 is detected. SUMm (RF) signal, tracking signal TEm, focus error signal FE at main spot 2 is detected. SUMm (RF) signal, tracking signal TEm, focus error signal FE at main spot
m is formed by the following operation. SUMm = A + B + C + D FEm = (A + C) − (B + D) TEm = (A + D) − (B + C) The DPP signal is a subspot PP signal at TEm. m is formed by the following operation. SUMm = A + B + C + D FEm = (A + C) − (B + D) TEm = (A + D) − (B + C) The DPP signal is a subspot PP signal at TEm.
The Es signal is added by adjusting the gain of the spot intensity ratio K. DPP = (A + D) − (B + C) −K × ｛(E1 + F The Es signal is added by adjusting the gain of the spot intensity ratio K. DPP = (A + D) − (B + C) −K × {(E1 + F)
1)-(E2 + F2)｝ 1)-(E2 + F2)}

【００１７】これまでの論文や実験結果ではＰＰ誤差信号と非点収差検出法でのＦＥクロストークは光学系収差や、光ピックアップの調整の違いの条件で変化するがある相関関係があり、ＦＥクロストークはトラックピッチ周期の信号でＰＰ誤差信号と振幅、位相に於いて一定の関係があるためリサージュ波形を描くことができる。これよりＰＰ信号より、ＦＥクロストークに近似した信号を形成できる関係にあると言える。以下上記関係より、

【００１８】１）ＤＰＰ用３ビームのサブスポットのＰ Ｐ信号を用いてＦＥクロストーク信号を形成する場合。 光検出器１８のＥ１、Ｅ２、Ｆ１、Ｆ２より検出した信号で形成したサブＰＰ誤差信号であるＴＥｓ信号とサブスポットで形成される非点収差法によるＦＥクロストーク信号の関係を検討する。メインスポットより形成したＰＰ信号であるＴＥｍ信号とＦＥクロストーク成分（Ｆ Ｅｍｃ）には相関関係がある。振幅の関係についてはＴ
Ｅｍ信号は正弦波に近い波形であるがＦＥクロストークは非正弦波であることがあり、２つの波形の関係は必ずしもリニアーなものではなく非線形な関係の場合もある。 The Em signal has a waveform close to a sinusoidal wave, but the FE crosstalk may be a non-sinusoidal wave, and the relationship between the two waveforms is not necessarily linear and may be non-linear. この場合でも２つの信号はトラックピッチを周期とした信号であるため、振幅の相互関係は記述でき、そのレベル関係をＲＯＭなどに記憶される一般的な表として表すことができる。 Even in this case, since the two signals are signals whose period is the track pitch, the mutual relationship between the amplitudes can be described, and the level relationship can be expressed as a general table stored in a ROM or the like. これを振幅関係のＧ（レベル関係の関数）と位相差項ｅ（ｊθ）で示すと、ＦＥｍｃを下記式１のように近似することができる。 Expressing this with the amplitude-related G (level-related function) and the phase difference term e (jθ), FEmc can be approximated as shown in Equation 1 below. ＦＥｍｃ＝Ｇ×ｅ（ｊθ）×ＴＥｍ … （１） 表のデータは内径方向及び外径方向移動時のトラックピッチ一周期分のこの関係データである。 FEmc = G × e (jθ) × TEm ... (1) The data in the table is this relational data for one cycle of the track pitch when moving in the inner diameter direction and the outer diameter direction. 尚、式１中のｊ In addition, j in equation 1
は−１の平方根を示し、θは位相を示す。 Indicates the square root of -1, and θ indicates the phase. 1) P of sub-spot of three beams for DPP 1) P of sub-spot of three beams for DPP
When forming an FE crosstalk signal using the P signal. The relationship between the TEs signal, which is a sub-PP error signal formed by the signals detected from E1, E2, F1, and F2 of the photodetector 18, and the FE crosstalk signal formed by the astigmatism method formed by the sub-spot will be examined. The TEm signal, which is the PP signal formed from the main spot, and the FE crosstalk component (F When forming an FE crosstalk signal using the P signal. The relationship between the TEs signal, which is a sub-PP error signal formed by the signals detected from E1, E2, F1, and F2 of the photodetector 18, and the FE crosstalk signal formed by the astigmatism method formed by the sub-spot will be examined. The TEm signal, which is the PP signal formed from the main spot, and the FE crosstalk component (F)
Emc) has a correlation. For the relationship between the amplitudes, Emc) has a correlation. For the relationship between the amplitudes,
Although the Em signal has a waveform close to a sine wave, the FE crosstalk may be a non-sine wave, and the relationship between the two waveforms is not necessarily linear but may be non-linear. Even in this case, since the two signals are signals having a cycle of the track pitch, the mutual relationship between the amplitudes can be described, and the level relationship can be represented as a general table stored in a ROM or the like. When this is represented by G in amplitude relation (function of level relation) and phase difference term e (jθ), FEmc can be approximated as in the following equation 1. FEmc = G × e (jθ) × TEm (1) The data in the table is the relation data for one period of the track pitch during the movement in the inner diameter direction and the outer diameter direction. Note that j in the equation 1 Although the Em signal has a waveform close to a sine wave, the FE crosstalk may be a non-sine wave, and the relationship between the two waveforms is not necessarily linear but may be non-linear. Even in this case, since the two signals are signals having a cycle of the track pitch, the mutual relationship between the amplitudes can be described, and the level relationship can be represented as a general table stored in a ROM or the like. When this is represented by G in amplitude relation ( function of level relation) and phase difference term e (jθ), FEmc can be approximated as in the following equation 1. FEmc = G × e (jθ) × TEm (1) The data in the table is the relation data for one period Note that j in the equation 1 of the track pitch during the movement in the inner diameter direction and the outer diameter direction.
Indicates the square root of -1, and θ indicates the phase. Indicates the square root of -1, and θ indicates the phase.

【００１９】また、上述のようにサブスポットによるＰＰ信号をＴＥｓ信号とする。また、サブスポットによるＦＥクロストーク成分をＦＥｓｃと表現する。本案の構成はＤＰＰ検出用のサブスポット用の光検出器は２分割セグメントであるため４分割セグメントのように非点収差誤差信号を演算できない。もし、４分割セグメントを構成し、ここよりフォーカス信号形成の演算をしたとするとそのＦＥ信号に混入するＦＥクロストークＦＥｓｃ

【００２０】ただしメインスポットもサブスポットの場合も、ＦＥ信号は面ぶれに関係した信号であり、ＰＰ信号は偏芯に関係する信号であるため、これらの２信号間には何ら相関関係はないため、ＰＰ信号から演算によりＦＥ信号そのものを求めることはできない。単に、相互にトラック渡りに関係したクロストーク成分のみが得られるだけである。ＴＥｍ信号とＴＥｓ信号を形成する光検出器のＥ１、Ｅ２、Ｆ１、Ｆ２によるトラッキング信号であるＴＥｓｅ信号とＴＥｓｆ信号はメインスポットとサブスポットの位置関係による位相差がある。しかし、ＴＥｓ信号を形成するため前後の信号を差動演算すると後述のようにＴＥｍ信号と逆相の信号となり、グレーティングの回転で変化するスポット位置は合成したＴ

【００２１】ここでＸを位置とし、Ｑをグレーティングにより設定されたスポットの位置、ＰをトラックピッチとしてメインスポットによるＰＰ信号をＴＥｍ信号、２つのサブスポットによるＰＰ信号をＴＥｓ１信号、ＴＥ

【００２２】ここでサブスポットによるＰＰ信号であるＴＥｓ信号の形成でＢ１＝Ｂ２とすると、ＴＥｓ信号は下記式のようになる。 ＴＥｓ＝Ｂ１×ＳＩＮ（２πＸ／Ｐ）×ＣＯＳ（２πＱ
／Ｐ） ここでＣＯＳ（Ｑ／Ｐ×２π）の関係は×に関係したない振幅項でサブスポットで合成したＴＥ信号の振幅変化を表し、トラッキング検出信号はメインスポットによるＰＰ信号に対してＱ／Ｐ＜１／４では＋振幅で同相、１ / P) Here, the relationship of COS (Q / P × 2π) represents the amplitude change of the TE signal synthesized in the sub-spot with the amplitude term not related to ×, and the tracking detection signal is Q with respect to the PP signal by the main spot. When / P <1/4, + amplitude is in phase, 1
／４＜Ｑ／Ｐ＜３／４では−振幅で逆相となる。 When / 4 <Q / P <3/4, the phase is reversed at -amplitude. ＤＰＰ DPP
信号の検出の場合はＱ＝Ｐ／２で上記ＣＯＳの振幅項は−１となって、逆相で、かつ、最大振幅となる。 In the case of signal detection, Q = P / 2 and the amplitude term of the COS is -1, which is the opposite phase and the maximum amplitude. Here, assuming that B1 = B2 in forming the TEs signal which is a PP signal by the sub spot, the TEs signal is represented by the following equation. TEs = B1 × SIN (2πX / P) × COS (2πQ Here, assuming that B1 = B2 in forming the TEs signal which is a PP signal by the sub spot, the TEs signal is represented by the following equation. TEs = B1 x SIN (2πX / P) x COS (2πQ)
/ P) Here, the relationship of COS (Q / P × 2π) represents a change in the amplitude of the TE signal synthesized by the sub-spot in an amplitude term not related to x, and the tracking detection signal is Q to the PP signal by the main spot. When / P <１ ／, in-phase with + amplitude, 1 / P) Here, the relationship of COS (Q / P × 2π) represents a change in the amplitude of the TE signal synthesized by the sub-spot in an amplitude term not related to x, and the tracking detection signal is Q to the PP signal by the main spot. When / P <1 /, in-phase with + amplitude, 1
In the case of / 4 <Q / P <3/4, the phase is reversed at the negative amplitude. DPP In the case of / 4 <Q / P <3/4, the phase is reversed at the negative amplitude. DPP
In the case of detecting a signal, the amplitude term of the COS becomes -1 at Q = P / 2, so that the phase is in the opposite phase and has the maximum amplitude. In the case of detecting a signal, the amplitude term of the COS becomes -1 at Q = P / 2, so that the phase is in the opposite phase and has the maximum amplitude.

【００２３】ＤＰＰ用のサブスポットはＤＶＤ−ＲＷのトラックピッチＰ＝０．７４μｍのときＱ＝Ｐ／２になるように設定されている。このため、ＤＶＤ−ＲＡＭ
４．７ＧＢの場合はＱ＝１．２×Ｐ／２となり、振幅は−１より少なくなる。 In the case of 4.7 GB, Q = 1.2 × P / 2, and the amplitude is less than -1. Ｑの位置で形成されたＰＰ信号やここで検出されたと仮定するフォーカス誤差信号のＦＥ FE of PP signal formed at position Q and focus error signal assumed to be detected here
クロストーク信号はＱ／Ｐの比で決まる位相差であるが前後のスポットを演算したＴＥｓ信号は同相また逆相の関係である。 The crosstalk signal has a phase difference determined by the Q / P ratio, but the TEs signal obtained by calculating the front and rear spots has an in-phase or anti-phase relationship. ここでＴＥｓ信号より形成されるＦＥｓｃ Here, the FEsc formed from the TEs signal
信号はＦＥｍｃ信号とは１／２トラックピッチ位相の違った波形と仮定できる。 The signal can be assumed to have a waveform with a 1/2 track pitch phase different from that of the FEmc signal. The sub-spot for DPP is set so that Q = P / 2 when the track pitch P of the DVD-RW is 0.74 μm. For this reason, DVD-RAM The sub-spot for DPP is set so that Q = P / 2 when the track pitch P of the DVD-RW is 0.74 μm. For this reason, DVD-RAM
In the case of 4.7 GB, Q = 1.2 × P / 2, and the amplitude is smaller than −1. FE of the PP signal formed at the position of Q and the focus error signal assumed to be detected here In the case of 4.7 GB, Q = 1.2 × P / 2, and the amplitude is smaller than −1. FE of the PP signal formed at the position of Q and the focus error signal assumed to be detected here
The crosstalk signal has a phase difference determined by the Q / P ratio, but the TEs signal obtained by calculating the front and rear spots has an in-phase or anti-phase relationship. Here, FEsc formed from the TEs signal The crosstalk signal has a phase difference determined by the Q / P ratio, but the TEs signal obtained by calculating the front and rear spots has an in-phase or anti-phase relationship. Here, FEsc formed from the TEs signal
The signal can be assumed to be a waveform having a half track pitch phase different from that of the FEmc signal. The signal can be assumed to be a waveform having a half track pitch phase different from that of the FEmc signal.

【００２４】本発明では先の式１の関係（振幅と位相を含んだ）をハード化するため、ＴＥｍ信号の波形の一周期を時間軸方向で分割し、そのタイミングでクロストーク成分をメモリーする。このため振幅方向で等分割したレベルと入力波形を比較し、そのレベルに到達したタイミングを形成し、そのタイミングで対応したＦＥクロストーク波形データをメモリーに記録する。例えばＡＤ変換器でＴＥｍ信号の波形を３２分割し、その波形レベルに一致した時点でのＦＥクロストークレベルをメモリーに取り込む。しかし、ＴＥｍ信号の波形に対するＦＥクロストーク波形はトラックの渡り方向とその渡りの速さ、フォーカス引込点によって異なる。このため補正する直前に実際の波形を取り込み、これをメモリーする手順が必要である。In the present invention, in order to harden the relationship (including the amplitude and the phase) of the above equation 1, one cycle of the waveform of the TEm signal is divided in the time axis direction, and the crosstalk component is stored at that timing. . For this reason, the level equally divided in the amplitude direction is compared with the input waveform, the timing when the level is reached is formed, and the FE crosstalk waveform data corresponding to the timing is recorded in the memory. For example, the waveform of the TEm signal is divided into 32 by the AD converter, and the FE crosstalk level at the time when the waveform level matches the waveform level is stored in the memory. However, the FE crosstalk waveform with respect to the waveform of the TEm signal differs depending on the crossing direction of the track, the speed of the crossing, and the focus pull-in point. For this reason, it is necessary to take a procedure for taking in an actual waveform just before correction and storing it.

【００２５】次に先の式２の関係でサブスポットによるＦＥクロストークを形成する。これは前記波形の取り込みによりＰＰ信号に対する、ＦＥクロストーク信号の関係がメモリーに取り込まれていると、サブスポットによるＰＰ信号を入力信号とし、振幅の最大値を波形を取り込んだ時のＰＰ信号の振幅と同じにして、振幅方向で分割を行いそのレベルに一致したタイミングでメモリーに記録されたデータを読み出し、アナログ波形に変換すると、先の式２の関係によるクロストーク成分ＦＥｓｃが形成されることになる。このようにしてサブスポットによるＦＥクロストーク成分を形成し、これをメインスポットによるＦＥクロストーク成分と演算する。この場合は、クロストーク成分が１／２トラックピッチ位相の異なった波形であるため加算する。これより、ＦＥクロストーク成分がある程度抑圧される。但し、この演算はＦ

【００２６】２）メインのスポットにおける、ＰＰ信号とＦＥクロストーク成分の関係の基本特性をもとに周期成分を打ち消す場合。 この場合も同様にフォーカス信号は形成できないため、
ＦＥクロストーク成分の打ち消しのみである。 It only cancels the FE crosstalk component. ＦＥ信号の瞬時瞬時の変動には対応しないで平均的なクロストーク成分を想定して打ち消す方式であるため、打ち消しによるＦＥの誤差は幾分かは発生する。 Since it is a method of canceling by assuming an average cross talk component without corresponding to the instantaneous fluctuation of the FE signal, some FE error due to the cancellation occurs. この場合は自分自身で周期成分を形成しているため、１／２トラックピッチで対称なＦＥクロストーク成分の場合でなくても打ち消すことができる。 In this case, since the periodic component is formed by itself, it can be canceled even if the FE crosstalk component is symmetric at 1/2 track pitch. この原理は前記サブスポットの場合と同じ過程でＴＥｍ信号により、ＦＥクロストークをメモリーする。 This principle stores FE crosstalk by a TEm signal in the same process as in the case of the subspot. このデータをメインスポットのＴＥｍ信号により読み出して、補正波形を形成し、この補正波形とＦＥｍ信号とを演算する。 This data is read out from the TEm signal of the main spot to form a correction waveform, and the correction waveform and the FEm signal are calculated. この補正波形はＦＥｍ信号と同相であるため、引き算となる。 Since this correction waveform is in phase with the Fem signal, it is subtracted. 2) A case where the periodic component is canceled based on the basic characteristics of the relationship between the PP signal and the FE crosstalk component in the main spot. In this case as well, a focus signal cannot be formed. 2) A case where the periodic component is canceled based on the basic characteristics of the relationship between the PP signal and the FE crosstalk component in the main spot. In this case as well, a focus signal cannot be formed.
Only cancellation of the FE crosstalk component is performed. Since the cancellation is performed by assuming an average crosstalk component without responding to the instantaneous fluctuation of the FE signal, some error of the FE due to the cancellation occurs. In this case, since the periodic component is formed by itself, the FE crosstalk component can be canceled even if it is not a FE crosstalk component symmetrical at a half track pitch. This principle stores the FE crosstalk by the TEm signal in the same process as in the case of the sub spot. This data is read by the TEm signal of the main spot to form a correction waveform, and the correction waveform and the FEm signal are calculated. Since this correction waveform has the same phase as the FEm signal, it is subtracted. Only cancellation of the FE crosstalk component is performed. Since the cancellation is performed by assuming an average crosstalk component without responding to the instantaneous fluctuation of the FE signal, some error of the FE due to the cancellation occurs. In this case, since the periodic component is formed by itself, the FE crosstalk component can be canceled even if it is not a FE crosstalk component symmetrical at a half track pitch. This principle stores the FE crosstalk by the TEm signal in the same process as in the case of the sub This data is read by the TEm signal of the main spot to form a correction waveform, and the correction waveform and the FEm signal are calculated. Since this correction waveform has the same phase as the FEm signal, it is subtracted.

【００２７】さて、ここで上述のような演算処理を行なう補正制御系４４（図２参照）を図３に基づいて具体的に説明する。図３において、５０はＦＥｍ信号をＡ／Ｄ変換するＡ／Ｄ変換器、５２は変換された波形のデジタル信号を記憶する波形記憶部、５４はこの波形記憶部５２から出力されたデジタル波形信号をアナログ信号に変換して補正波形信号を形成するＤ／Ａ変換器、５６はＦＥｍ信号と補正波形信号とを演算して補正ＦＥ信号を形成する演算部である。また、ＳＷは入力する信号をｍ側とｓ側との間で切り替える切替スイッチ群、５８はＴＥ信号のレベルを比較するレベル比較器、６０，６２はそれぞれＴＥ信号とＳＵＭ信号を２値化する２値化回路、

【００２８】次に、この補正制御系４４の動作について説明する。まず、図２に示す信号処理系で形成された各信号の内、ＦＥｍ信号（フォーカスエラー信号）、ＴＥｍ信号（トラッキングエラー信号）、ＴＥｓ信号、ＳＵＭｍ信号、ＳＵＭｓ信号の各信号が補正制御系４４へ入力される。メインスポットを受光する４分割セグメント１８Ａ（図２参照）より得られた上記ＦＥｍ信号は、Ａ／Ｄ変換器５０でデジタルデータに変換される。フォーカスエラー信号は帯域３０ＫＨｚで−３ｄＢ低下のＬＰＦ（ローパスフィルタ）で処理された信号であり、Ａ／

【００２９】メインスポットから形成されたＰＰ誤差信号であるＴＥｍ信号は最大振幅値を一定のレベルに合わせた後、例えばレベル比較器よりなるレベル比較部５８

【００３０】また、トラック横断の方向検出を行うためＴＥｍ信号は２値化回路６０にて２値化される。メインスポットの総和信号はＳＵＭｍ信号として入力される。同様にサブスポットによるＰＰ誤差信号であるＴＥｓ信号、総和信号であるＳＵＭｓ信号が入力される。ＳＵＭ

【００３１】またＰＰ信号の０−９０°、９０−１８０°１８０−２７０°、２７０−３６０°の各領域を検出して区別するため２ビット（アドレスＡＤ６、ＡＤ７）が使われる。また、ＴＥｍ信号の波形は前述のようにレベル比較部５８で例えば３２段階（６ビットＡＤ５〜ＡＤ０）に分割され、そのレベルに到達するタイミングとアドレスが形成される。また、方向信号がアドレスＡＤ

【００３２】補正波形を読取りピックアップがフィード機構で遅い速度で送られている場合やスチル（１トラックジャンプ）の場合とを区別する場合には速度の高低がアドレスＡＤ９として加えられる。この結果、アドレスＡＤ９〜ＡＤ０の１０ビットのアドレスで区別された波形記憶部５２にＦＥクロストーク電圧が記憶される。高速送りの場合での信号変化が少ない場合はアドレスＡＤ
９を省略し、全体で９ビットのアドレスを用いるようにしてもよい。 9 may be omitted and a 9-bit address may be used as a whole. ディスクを立ち上げた後、フォーカスサーボのみがかかった状態で、初期、ＦＥクロストーク信号を１周期だけ波形記憶部５２に記録する。 After the disk is started up, the FE crosstalk signal is initially recorded in the waveform storage unit 52 for only one cycle with only the focus servo applied. 最初ＦＥクロストーク信号を記録する過程は、フォーカスサーボ動作後、ＴＥｍ信号とＳＵＭｍ信号により、ＰＰ信号に対応したＦＥクロストーク信号が波形記憶部５２に記録される。 In the process of first recording the FE crosstalk signal, after the focus servo operation, the FE crosstalk signal corresponding to the PP signal is recorded in the waveform storage unit 52 by the TEm signal and the SUMm signal. これは比較的サーボループゲインが低い状態で、Ｆ This is a state where the servo loop gain is relatively low, F
Ｅクロストーク信号誤差レベルがそのままの状態で、トラック渡りが内周側及び外周側方向の１回または複数回取り込み、平均化して波形記憶部５２にＦＥクロストーク信号を記録してもよい。 The FE crosstalk signal may be recorded in the waveform storage unit 52 by capturing and averaging the track crossing once or a plurality of times in the inner peripheral side and the outer peripheral side while keeping the E crosstalk signal error level as it is. When the correction waveform is read and the pickup is fed at a low speed by the feed mechanism or when the still (single track jump) is distinguished, the speed is added as the address AD9. As a result, the FE crosstalk voltage is stored in the waveform storage unit 52 identified by the 10-bit addresses AD9 to AD0. If the signal change in high-speed feeding is small, the address AD When the correction waveform is read and the pickup is fed at a low speed by the feed mechanism or when the still (single track jump) is distinguished, the speed is added as the address AD9. As a result, the FE crosstalk voltage is stored in the waveform storage unit 52 identified by the 10-bit addresses AD9 to AD0. If the signal change in high-speed feeding is small, the address AD
9 may be omitted and a 9-bit address may be used as a whole. After the disk is started, the FE crosstalk signal is initially recorded in the waveform storage unit 52 for one cycle while only the focus servo is applied. In the process of recording the FE crosstalk signal first, after the focus servo operation, the FE crosstalk signal corresponding to the PP signal is recorded in the waveform storage unit 52 by the TEm signal and the SUMm signal. This is because the servo loop gain is relatively low and F 9 may be omitted and a 9-bit address may be used as a whole. After the disk is started, the FE crosstalk signal is initially recorded in the waveform storage unit 52 for one cycle while only the focus servo is applied. In the process This is because the servo loop gain is relatively low of recording the FE crosstalk signal first, after the focus servo operation, the FE crosstalk signal corresponding to the PP signal is recorded in the waveform storage unit 52 by the TEm signal and the SUMm signal. and F
The FE crosstalk signal may be recorded in the waveform storage unit 52 after the track crossing is captured once or plural times in the inner circumferential direction and the outer circumferential direction while the E crosstalk signal error level remains unchanged. The FE crosstalk signal may be recorded in the waveform storage unit 52 after the track crossing is captured once or plural times in the inner transmitting direction and the outer generating direction while the E crosstalk signal error level remains unchanged.

【００３３】次に、トラック横断時のクロストークを補正する。この動作は波形記憶部５２に記録した波形データをサブスポットによるＴＥｓ信号で取り出す工程になる。ここでは前記同様にサブスポットによるＴＥｓ信号とＳＵＭｓ信号が前記メインスポットのＴＥｍ信号とＳＵＭｍ信号に置き換わって入力される。これより方向検出、領域検出が行われ、ＴＥｓ信号はレベル変換部５８で３２分割され、アドレスデータが形成される。このアドレスデータが波形記憶部５２に入力され、ＴＥｓ信号に対応したレベルに対するＦＥクロストーク波形データが読み出され、このデータをＤ／Ａ変換器５４にてＤ／

【００３４】これをＦＥクロストーク成分がＴＥｓ信号と同様な正弦波で、位相差のある場合の例を図５に示す。ここでは、図５（Ａ）に示すようにＴＥｍ信号とＦ Ｅクロストークが約４０度の位相差の場合であり（図５
（Ｂ）参照）、ＴＥｍ信号でＦＥクロストーク波形を記録し、サブスポットによるＴＥｓ信号からクロストーク（補正波形信号）を形成し、クロストーク成分相殺の動作をした場合を行なっている。 (See (B)), the FE crosstalk waveform is recorded with the TEm signal, the crosstalk (correction waveform signal) is formed from the TEs signal by the subspot, and the crosstalk component canceling operation is performed. これにより、逆位相の補正ができて、溝渡りの成分は少なくなった（図５（Ｃ） As a result, the opposite phase can be corrected, and the groove crossing component is reduced (FIG. 5 (C)).
参照）。 reference). この結果、補正ＦＥ信号に混入するＦＥクロストーク信号が打ち消されて、高域信号成分が減少し、合焦誤差を低減し、フォーカス駆動コイルに流れる不要高周波成分が少なくなり、音の発生や発熱を防止して動作の安定性を確保することができる。 As a result, the FE crosstalk signal mixed in the corrected FE signal is canceled, the high frequency signal component is reduced, the focusing error is reduced, the unnecessary high frequency component flowing through the focus drive coil is reduced, and sound is generated and heat is generated. Can be prevented and the stability of operation can be ensured. FIG. 5 shows an example in which the FE crosstalk component is a sine wave similar to the TEs signal and has a phase difference. Here, as shown in FIG. FIG. 5 shows an example in which the FE crosstalk component is a sine wave similar to the TEs signal and has a phase difference. Here, as shown in FIG.
FIG. 5 shows a case where E crosstalk has a phase difference of about 40 degrees (FIG. 5). FIG. 5 shows a case where E crosstalk has a phase difference of about 40 degrees (FIG. 5).
(See (B)), an FE crosstalk waveform is recorded by the TEm signal, a crosstalk (corrected waveform signal) is formed from the TEs signal by the sub spot, and the operation of canceling the crosstalk component is performed. As a result, the opposite phase can be corrected, and the component of the groove crossing is reduced (FIG. 5C). (See (B)), an FE crosstalk waveform is recorded by the TEm signal, a crosstalk (corrected waveform signal) is formed from the TEs signal by the sub spot, and the operation of canceling the crosstalk component is performed. As a result , the opposite phase can be corrected, and the component of the groove crossing is reduced (FIG. 5C).
reference). As a result, the FE crosstalk signal mixed in the corrected FE signal is canceled, the high frequency signal component is reduced, the focusing error is reduced, the unnecessary high frequency component flowing through the focus drive coil is reduced, and the generation of sound and heat generation Can be prevented and operation stability can be ensured. reference). As a result, the FE crosstalk signal mixed in the corrected FE signal is canceled, the high frequency signal component is reduced, the focusing error is reduced, the unnecessary high frequency component flowing through the focus drive coil is reduced, and the generation of sound and heat generation Can be prevented and operation stability can be ensured.

【００３５】このように上記各波形が正弦波に近い場合は相殺波形を逆位相で形成でき、補正の効果がある。しかし、図６に示すようにＦＥクロストークが歪み波形となって、また、１／２トラックピッチ遅れの波形が対称波形で無い場合は１／２トラックピッチ離れた位置でのクロストークが完全に逆極性の信号とならないため、相殺の効果が少なくて前例のような効果は得られない。また、前述のようにクロストーク信号形成の波形はメインスポットによるＴＥｍ信号で形成してもよい。ここで波形記憶部５２に記録した波形の取り出しを前例ではＴＥ

【００３６】前記方式はＦＥクロストーク波形の記録と補正を行う信号入力を切り替えていたが、本方式では信号を切り替えない。また、この場合はＦＥクロストークが同じ位相で得られるため、演算部５６における演算が引き算になる。図７にはメインスポットによる方式の波形図を示す。メインスポットによる場合は逆極性とできるため、相殺によりクロストークを抑圧できる。また、

【００３７】 [0037]

【発明の効果】以上、本発明の光ディスク再生装置によれば、次のように優れた作用効果を発揮することができる。本方式でクロストークを補正した結果、ランドグルーブ方式の光ディスクを非点収差法のフォーカス検出で誤差信号を検出したとき、ＦＥ信号に混入するＦＥクロストーク信号が打ち消されて、高域信号成分が減少し、
合焦誤差を低減し、フォーカス駆動コイルに流れる不要高周波電流成分が少なくなり、音の発生やコイルの発熱を防止し、サーボ動作の安化、素子の温度特性の安定化を確保することができる。 Focusing error can be reduced, unnecessary high-frequency current components flowing through the focus drive coil can be reduced, sound generation and coil heat generation can be prevented, servo operation can be reduced, and element temperature characteristics can be stabilized. .. As described above, according to the optical disk reproducing apparatus of the present invention, the following excellent functions and effects can be exhibited. As a result of correcting crosstalk by this method, when an error signal is detected on the land-groove type optical disk by the focus detection by the astigmatism method, the FE crosstalk signal mixed into the FE signal is canceled, and the high-frequency signal component is reduced. Decreased, As described above, according to the optical disk reproducing apparatus of the present invention, the following excellent functions and effects can be exhibited. As a result of correcting crosstalk by this method, when an error signal is detected on the land-groove type optical disk by the focus detection by the astigmatism method, the FE crosstalk signal mixed into the FE signal is canceled, and the high-frequency signal component is reduced. Decreased,
Reduces focusing error, reduces unnecessary high-frequency current components flowing through the focus drive coil, prevents sound generation and coil heat generation, ensures stable servo operation, and stabilizes element temperature characteristics. . Reduces focusing error, reduces unnecessary high-frequency current components flowing through the focus drive coil, prevents sound generation and coil heat generation, ensures stable servo operation, and stabilizes element temperature characteristics.

【図１】本発明に係る光ディスク再生装置に用いる光ピックアップの一例を示す構成図である。 FIG. 1 is a configuration diagram showing an example of an optical pickup used in an optical disk reproducing device according to the present invention.

【図２】光ピックアップからの信号を処理する信号処理系を示すブロック構成図である。 FIG. 2 is a block diagram showing a signal processing system for processing a signal from an optical pickup.

【図３】信号処理系で得られる各信号からフォーカスエラー（ＦＥ）信号を補正する補正制御系を示すブロック構成図である。 FIG. 3 is a block diagram showing a correction control system for correcting a focus error (FE) signal from each signal obtained by a signal processing system.

【図４】方向検出部における信号波形の状態を領域区分及び方向信号と共に示す図である。 FIG. 4 is a diagram showing a state of a signal waveform in a direction detection unit together with a region division and a direction signal.

【図５】ＦＥクロストーク成分がＴＥｓ信号と同様な正弦波で、位相差のある場合の例を示す図である。 FIG. 5 is a diagram illustrating an example in which an FE crosstalk component is a sine wave similar to the TEs signal and has a phase difference.

【図６】ＦＥ補正波形信号を示す図である。 FIG. 6 is a diagram showing an FE correction waveform signal.

【図７】メインスポットによる方式のクロストーク波形図を示す。 FIG. 7 shows a crosstalk waveform diagram of a system using a main spot.

２…光ピックアップ、４…グレーティング、６…偏光ビームスプリッタ、１０…λ／４板、１４…光ディスク、 １６…シリンドリカルレンズ、１８…光検出器、４４…補正制御系、５２…波形記憶部、５６…演算部、５８…レベル比較部、６４…方向検出部、６６…アドレス形成部。 2 optical pickup, 4 grating, 6 polarization beam splitter, 10 λ / 4 plate, 14 optical disk,
16: cylindrical lens, 18: photodetector, 44 ...
Correction control system, 52: waveform storage unit, 56: calculation unit, 58 ... Correction control system, 52: waveform storage unit, 56: calculation unit, 58 ...
Level comparison unit, 64: direction detection unit, 66: address formation unit Level comparison unit, 64: direction detection unit, 66: address formation unit