JP2002032924A - Offset detector and compensator for optical head - Google Patents
Offset detector and compensator for optical headInfo
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- JP2002032924A JP2002032924A JP2000214663A JP2000214663A JP2002032924A JP 2002032924 A JP2002032924 A JP 2002032924A JP 2000214663 A JP2000214663 A JP 2000214663A JP 2000214663 A JP2000214663 A JP 2000214663A JP 2002032924 A JP2002032924 A JP 2002032924A
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- light receiving
- light
- divided
- focus error
- focus
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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、フォーカス制御が
非点収差法により行われる光学ヘッドにおける光検出器
の４分割の受光領域に対する受光スポットの位置ズレに
対応するオフセットを検出する光学ヘッドのオフセット
検出装置、及びそのオフセットを補正する光学ヘッドの
オフセット補正装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an offset of an optical head for detecting an offset corresponding to a positional deviation of a light receiving spot with respect to a light receiving area divided into four by a photo detector in an optical head in which focus control is performed by an astigmatism method. The present invention relates to a detection device and an offset correction device for an optical head that corrects the offset.
【０００２】[0002]
【従来の技術】ディスク等の信号記録媒体に対して光ビ
ームを用いて光学的に信号の読み取り、あるいは書き込
みを行う光学ヘッドにおいては、光ビームの焦点を信号
記録媒体の信号面に合焦させるフォーカス制御を行うの
に信号記録媒体により反射された光ビームに非点収差を
付与し、その光ビームを非点収差の発生方向に応じて方
向が設定された十字状の分割線により分割した４分割の
受光領域に受光し、その分割された各受光領域における
各受光出力のそれぞれ対角線上に配置される各受光領域
の各受光レベルをそれぞれ加算した各加算受光レベルの
差を検出してフォーカスエラー信号を得ており、このフ
ォーカスエラー信号レベルに応じて対物レンズをフォー
カス方向に変位することによりフォーカス制御を行う、
いわゆる非点収差法が主流になっている。2. Description of the Related Art In an optical head that optically reads or writes a signal on a signal recording medium such as a disk by using a light beam, the light beam is focused on a signal surface of the signal recording medium. In order to perform focus control, astigmatism is given to the light beam reflected by the signal recording medium, and the light beam is divided by a cross-shaped dividing line whose direction is set according to the direction in which astigmatism occurs. Light is received by the divided light receiving areas, and the light receiving level of each light receiving output of each divided light receiving area is added to each light receiving area of each light receiving area arranged on a diagonal line. Signal, and performs focus control by displacing the objective lens in the focus direction according to the focus error signal level.
The so-called astigmatism method has become mainstream.
【０００３】ところで、非点収差を付与した光ビームが
光検出器に受光されて形成される受光スポットには非点
収差の影響を受けた非点収差パターンが現れ、その非点
収差パターンは信号面に対して光ビームの焦点が前方か
後方かにより楕円長径の方向が９０度異なり、信号面に
対して光ビームの焦点が一致する合焦点において略真円
形となるように設定される。[0003] Incidentally, an astigmatism pattern affected by astigmatism appears in a light receiving spot formed by receiving a light beam having astigmatism on a photodetector. The direction of the major axis of the ellipse differs by 90 degrees depending on whether the focal point of the light beam is forward or rearward with respect to the plane, and is set so as to be substantially a perfect circle at the focal point where the focal point of the light beam coincides with the signal plane.
【０００４】そして、フォーカスエラー信号は、周知の
如く、光ビームの焦点と信号面との距離によって電圧レ
ベルが増減すると共に、光ビームの焦点が信号面より前
方か後方かにより極性が逆となる、いわゆるＳ字カーブ
特性となり、この場合、電圧レベルが「０」の点が光ビ
ームの焦点と信号面との合焦点に設定される。As is well known, the voltage level of the focus error signal increases and decreases depending on the distance between the focal point of the light beam and the signal surface, and the polarity of the signal is reversed depending on whether the focal point of the light beam is ahead or behind the signal surface. In this case, the point where the voltage level is "0" is set as the focal point between the focal point of the light beam and the signal surface.
【０００５】すなわち、光ビームの焦点が信号面に対し
て合焦状態にあるとき、光検出器上の受光スポットは略
真円形に設定され、フォーカスエラー信号の電圧レベル
が「０」に設定され、この場合、受光スポットの中心が
光検出器の４分割の受光領域を形成するべく十字状に配
置される各分割線の交点に一致されるように調整され
る。That is, when the focal point of the light beam is in focus with respect to the signal surface, the light receiving spot on the photodetector is set to a substantially perfect circle, and the voltage level of the focus error signal is set to "0". In this case, the adjustment is performed such that the center of the light receiving spot coincides with the intersection of the dividing lines arranged in a cross shape so as to form a four-divided light receiving area of the photodetector.
【０００６】[0006]
【発明が解決しようとする課題】ところで、光学ヘッド
の組立時や経時変化における光検出器や光学素子の位置
ズレにより、あるいは光学ヘッドの組立時における光検
出器の位置調整精度により光検出器に投影される受光ス
ポットの位置ズレが発生する場合がある。By the way, the position of the photodetector or the optical element during the assembly of the optical head or a change with the passage of time, or the positional adjustment accuracy of the photodetector during the assembly of the optical head, causes the photodetector to have a problem. In some cases, the position of the projected light receiving spot is shifted.
【０００７】この受光スポットの位置ズレは、非点収差
法を採用した光学ヘッドの場合、受光スポットの中心が
光検出器の４分割の受光領域を形成するべく十字状に配
置される各分割線の交点からずれ、図２に示す如く、信
号面に対する光ビームの焦点位置の各状態、すなわち、
信号面に対して光ビームの焦点位置が前方にある状態
（図２（イ）に示す）、信号面に対して光ビームの焦点
位置が一致する合焦状態（図２（ロ）に示す）及び信号
面に対して光ビームの焦点位置が後方にある状態（図２
（ハ）に示す）における受光スポットの各非点収差パタ
ーンにおいて受光スポットの中心が各分割線の交点から
ずれる。In the case of an optical head employing the astigmatism method, the positional deviation of the light receiving spot is determined by dividing the light receiving spot by dividing lines arranged in a cross shape so as to form a four-divided light receiving area of the photodetector. 2. As shown in FIG. 2, each state of the focal position of the light beam with respect to the signal surface, that is,
A state in which the focal position of the light beam is ahead of the signal plane (shown in FIG. 2A), and a focused state in which the focal position of the light beam matches the signal plane (shown in FIG. 2B) And the state where the focal position of the light beam is behind the signal plane (FIG. 2).
(Shown in (c)), the center of the light receiving spot is shifted from the intersection of each dividing line in each astigmatism pattern of the light receiving spot.
【０００８】このように受光スポットの中心が各分割線
の交点からずれると、図２（ロ）に示す合焦状態におい
て、フォーカスエラー信号の電圧レベルが「０」になら
ず、信号面に対して光ビームの焦点位置がずれた状態で
フォーカス制御が行われるという問題が発生する。When the center of the light receiving spot deviates from the intersection of the dividing lines, the voltage level of the focus error signal does not become "0" in the in-focus state shown in FIG. This causes a problem that focus control is performed in a state where the focus position of the light beam is shifted.
【０００９】その為、非点収差法を採用した光学ヘッド
の場合、４分割の受光領域に対する受光スポットの位置
ズレに対応するオフセットを検出することは重要であ
る。Therefore, in the case of an optical head employing the astigmatism method, it is important to detect an offset corresponding to a positional shift of the light receiving spot with respect to the four divided light receiving areas.
【００１０】[0010]
【課題を解決するための手段】請求項１の発明は、フォ
ーカスエラー信号が「０」となる４分割の受光領域に投
影される受光スポットの受光状態における前記４分割の
受光領域における各受光出力の出力レベルを検出して前
記４分割の受光領域に対する受光スポットの位置ズレに
対応するオフセットを検出するようにしている。According to a first aspect of the present invention, each light receiving output in the four divided light receiving areas in a light receiving state of a light receiving spot projected on the four divided light receiving areas where the focus error signal is "0". Is detected to detect an offset corresponding to a positional shift of the light receiving spot with respect to the four divided light receiving areas.
【００１１】請求項２の発明は、フォーカスエラー信号
が「０」となる受光状態の検出をフォーカスサーチ時に
行うようにしている。According to a second aspect of the present invention, the detection of the light receiving state in which the focus error signal becomes "0" is performed during the focus search.
【００１２】請求項３の発明は、フォーカスエラー信号
が「０」となる受光状態における４分割の受光領域にお
ける各受光出力の出力レベルを等しくするべくフォーカ
スエラー信号に関係する受光レベルのレベル調整を行っ
てオフセット補正を行うようにしている。According to a third aspect of the present invention, the light receiving level related to the focus error signal is adjusted to equalize the output levels of the respective light receiving outputs in the four divided light receiving areas in the light receiving state where the focus error signal is "0". To perform offset correction.
【００１３】[0013]
【実施例】図１は本発明に係る光学ヘッドのオフセット
検出装置及びオフセット補正装置を備える光学ディスク
装置のフォーカス制御回路部分を示す回路ブロック図で
あり、図１に用いられる光学ヘッドはフォーカス制御に
非点収差法を採用される。FIG. 1 is a circuit block diagram showing a focus control circuit portion of an optical disk device provided with an offset detection device and an offset correction device for an optical head according to the present invention. The optical head used in FIG. An astigmatism method is adopted.
【００１４】図１を用いて以下に本発明を説明する。The present invention will be described below with reference to FIG.
【００１５】光学ヘッドの光検出器１には、ディスクを
照射する光ビームのフォーカス誤差に応じて非点収差が
付与されたディスクからの反射ビームを受光すると共
に、非点収差の発生方向と略４５度の向きで互いに直交
する十字状に配置される２本の分割線により４分割され
た各受光領域ａ，ｂ，ｃ，ｄからはそれぞれ受光される
光ビームの受光量に応じて各受光出力Ｓａ，Ｓｂ，Ｓ
ｃ，Ｓｄが発生される。The photodetector 1 of the optical head receives a reflected beam from a disk to which astigmatism has been given in accordance with a focus error of a light beam irradiating the disk, and has a direction substantially the same as the direction in which astigmatism occurs. Each of the light receiving areas a, b, c, and d divided into four by two dividing lines arranged in a cross shape orthogonal to each other in a 45-degree direction. Output Sa, Sb, S
c and Sd are generated.
【００１６】前記各受光出力Ｓａ，Ｓｂ，Ｓｃ，Ｓｄは
それぞれ電流・電圧変換アンプ２，３，４，５により電
流信号から電圧信号に変換され、その後、対角線上に配
置される各受光領域の各受光出力同士がそれぞれ加算さ
れて第１加算出力（Ｓａ＋Ｓｃ）及び第２加算出力（Ｓ
ｂ＋Ｓｄ）が生成される。The light-receiving outputs Sa, Sb, Sc, and Sd are converted from current signals to voltage signals by current / voltage conversion amplifiers 2, 3, 4, and 5, respectively. The respective light receiving outputs are added to each other to form a first addition output (Sa + Sc) and a second addition output (S
b + Sd) is generated.
【００１７】前記各加算出力（Ｓａ＋Ｓｃ）及び（Ｓｂ
＋Ｓｄ）はそれぞれアンプ６及び７に増幅された後、フ
ォーカスエラー信号生成回路（ＦＥ信号生成回路）８に
より（Ｓａ＋Ｓｃ）−（Ｓｂ＋Ｓｄ）の演算が行われ、
前記ＦＥ信号生成回路８はディスクの信号面に照射され
る光ビームの焦点とその信号面との誤差を示すフォーカ
スエラー信号（ＦＥ信号）を生成する。The sum outputs (Sa + Sc) and (Sb
+ Sd) is amplified by the amplifiers 6 and 7, respectively, and then the calculation of (Sa + Sc)-(Sb + Sd) is performed by the focus error signal generation circuit (FE signal generation circuit) 8.
The FE signal generation circuit 8 generates a focus error signal (FE signal) indicating an error between the focal point of the light beam applied to the signal surface of the disk and the signal surface.
【００１８】また、４分割の受光領域ａ，ｂ，ｃ，ｄか
らの各受光出力Ｓａ，Ｓｂ，Ｓｃ，Ｓｄはそれぞれレベ
ル検出回路９に入力され、そのレベル検出回路９はそれ
らの各受光出力Ｓａ，Ｓｂ，Ｓｃ，Ｓｄの電圧レベルＶ
ａ，Ｖｂ，Ｖｃ，Ｖｄを検出する。Each of the light receiving outputs Sa, Sb, Sc, and Sd from the four divided light receiving areas a, b, c, and d is input to a level detecting circuit 9, and the level detecting circuit 9 outputs the respective light receiving outputs. Voltage level V of Sa, Sb, Sc, Sd
a, Vb, Vc, and Vd are detected.
【００１９】レベル検出回路９により各受光出力の電圧
レベルＶａ，Ｖｂ，Ｖｃ，Ｖｄが検出されると、ゲイン
調整回路１０はそれらの各電圧レベルの和Ｖ＝Ｖａ＋Ｖ
ｂ＋Ｖｃ＋Ｖｄが予め設定される一定値になると共に、
各電圧レベルＶａ，Ｖｂ，Ｖｃ，Ｖｄが等しく（Ｖａ＝
Ｖｂ＝Ｖｃ＝Ｖｄ）なるようにアンプ６及び７のゲイン
を調整して第１加算出力（Ｓａ＋Ｓｃ）及び第２加算出
力（Ｓｂ＋Ｓｄ）のレベル調整を行う。When the voltage level Va, Vb, Vc, Vd of each light receiving output is detected by the level detecting circuit 9, the gain adjusting circuit 10 calculates the sum V = Va + V of the respective voltage levels.
b + Vc + Vd becomes a preset constant value, and
Each of the voltage levels Va, Vb, Vc, Vd is equal (Va =
The levels of the first addition output (Sa + Sc) and the second addition output (Sb + Sd) are adjusted by adjusting the gains of the amplifiers 6 and 7 so that Vb = Vc = Vd).
【００２０】次に、４分割の受光領域に対する受光スポ
ットの位置ズレが生じた場合について説明する。Next, a description will be given of a case where the position of the light receiving spot is shifted with respect to the light receiving area divided into four parts.
【００２１】例えば、４分割の受光領域に対する受光ス
ポットの位置ズレによるオフセットの発生により、図２
（イ）に示す如く、ディスクの信号面に対して光ビーム
の焦点位置が前方にある状態で、フォーカスエラー信号
が「０」となるようになると、図２（ロ）に示す実際の
合焦状態において、信号面に対して光ビームの焦点位置
が後方にずれていることを示すフォーカスエラー信号が
発生し、信号面に対して光ビームの焦点位置が前方にず
れた状態にフォーカス制御が行われることになる。For example, when an offset occurs due to a positional shift of the light receiving spot with respect to the light receiving area divided into four, the light receiving area shown in FIG.
As shown in FIG. 2A, when the focus error signal becomes "0" in a state where the focus position of the light beam is ahead of the signal surface of the disk, the actual focusing shown in FIG. In this state, a focus error signal indicating that the focal position of the light beam is shifted backward with respect to the signal surface is generated, and focus control is performed in a state where the focal position of the light beam is shifted forward with respect to the signal surface. Will be
【００２２】ところで、図１に示す回路構成を備える光
学ディスク装置は、ディスク再生開始準備時にフォーカ
スサーボ領域に導入するべく光学ヘッドの対物レンズを
フォーカス方向に駆動するフォーカスサーチが行われ、
このフォーカスサーチ時にフォーカスエラー信号が
「０」となる受光状態を検出し、その受光状態において
レベル検出回路９は４分割の受光領域ａ，ｂ，ｃ，ｄに
おける各受光出力の電圧レベルＶａ，Ｖｂ，Ｖｃ，Ｖｄ
を検出する。Incidentally, in the optical disk device having the circuit configuration shown in FIG. 1, a focus search for driving the objective lens of the optical head in the focus direction is performed in order to introduce the optical disk into the focus servo area at the time of preparation for starting disk reproduction.
During this focus search, a light receiving state in which the focus error signal becomes "0" is detected, and in this light receiving state, the level detection circuit 9 sets the voltage levels Va, Vb of the respective light receiving outputs in the four divided light receiving areas a, b, c, d. , Vc, Vd
Is detected.
【００２３】その為、レベル検出回路９によりフォーカ
スエラー信号が「０」となる受光状態における４分割の
受光領域ａ，ｂ，ｃ，ｄの各受光出力の電圧レベルＶ
ａ，Ｖｂ，Ｖｃ，Ｖｄが検出されることになり、この受
光状態においてゲイン調整回路１０はそれらの各電圧レ
ベルの和Ｖ＝Ｖａ＋Ｖｂ＋Ｖｃ＋Ｖｄが予め設定される
一定値とするようにしながら、各電圧レベルＶａ，Ｖ
ｂ，Ｖｃ，Ｖｄが等しく（Ｖａ＝Ｖｂ＝Ｖｃ＝Ｖｄ）な
るようにアンプ６及び７のゲインを調整する。Therefore, in the light receiving state where the focus error signal becomes "0" by the level detecting circuit 9, the voltage level V of each light receiving output of the four divided light receiving areas a, b, c and d is obtained.
a, Vb, Vc, and Vd are detected. In this light receiving state, the gain adjustment circuit 10 sets each voltage level while maintaining the sum V = Va + Vb + Vc + Vd of the respective voltage levels at a preset constant value. Va, V
The gains of the amplifiers 6 and 7 are adjusted so that b, Vc, and Vd are equal (Va = Vb = Vc = Vd).
【００２４】この場合、アンプ６はそれぞれ第１加算出
力（Ｓａ＋Ｓｃ）を増幅し、アンプ７は第２加算出力
（Ｓｂ＋Ｓｄ）を増幅するので、アンプ６のゲイン調整
は電圧レベルＶａ及びＶｃの両方を考慮して行われ、ア
ンプ７のゲイン調整は電圧レベルＶｂ及びＶｄの両方を
考慮して行われる。In this case, the amplifier 6 amplifies the first sum output (Sa + Sc), and the amplifier 7 amplifies the second sum output (Sb + Sd). Therefore, the gain adjustment of the amplifier 6 adjusts both the voltage levels Va and Vc. The gain adjustment of the amplifier 7 is performed in consideration of both the voltage levels Vb and Vd.
【００２５】このアンプ６及び７のゲイン調整は、４分
割の受光領域に対する受光スポットの位置ズレによって
受光出力が増減される各受光領域に対応して第１加算出
力（Ｓａ＋Ｓｃ）及び第２加算出力（Ｓｂ＋Ｓｄ）が補
償されるべく行われる。The gains of the amplifiers 6 and 7 are adjusted by a first added output (Sa + Sc) and a second added output corresponding to each light receiving area whose light receiving output is increased or decreased by the positional shift of the light receiving spot with respect to the four divided light receiving areas. This is performed so that (Sb + Sd) is compensated.
【００２６】このアンプ６及び７のゲイン調整によりア
ンプ６及び７のゲイン調整前においてフォーカスエラー
信号が「０」となる状態である図２（イ）に示すディス
クの信号面に対して光ビームの焦点位置が前方にある状
態においてはその状態に適合する極性及びレベルのフォ
ーカスエラー信号がフォーカスエラー信号生成回路８か
ら発生されるようになり、図２（ロ）に示す実際の合焦
状態においてフォーカスエラー信号が「０」となるよう
に補正される。By adjusting the gains of the amplifiers 6 and 7, the light beam is applied to the signal surface of the disk shown in FIG. 2A where the focus error signal becomes "0" before the gain adjustment of the amplifiers 6 and 7. When the focus position is in the forward position, a focus error signal having a polarity and a level suitable for that state is generated from the focus error signal generation circuit 8, and the focus is adjusted in the actual focus state shown in FIG. Correction is performed so that the error signal becomes “0”.
【００２７】したがって、フォーカスエラー信号生成回
路８により生成されるフォーカスエラー信号を用いて、
４分割の受光領域に対する受光スポットの位置ズレが生
じた場合でもディスクの信号面に正しく光ビームの焦点
位置を一致させるべくフォーカス制御が行えるようにな
る。Therefore, using the focus error signal generated by the focus error signal generation circuit 8,
Even when the position of the light receiving spot is displaced with respect to the light receiving area divided into four, the focus control can be performed so that the focal position of the light beam can be correctly matched with the signal surface of the disk.
【００２８】尚、図１に示す実施例において、４分割の
受光領域に対する受光スポットの位置ズレが生じた場合
のフォーカスエラー信号の補償は、４分割の受光領域に
おけるそれぞれ対角線上に配置される各受光領域の各受
光出力をそれぞれ加算した後の各加算出力レベルで調整
するようにして回路構成の簡潔化を図って達成している
が、これに限らず、加算する前の各受光領域の各受光出
力を個別にレベル調整することにより達成しても良いこ
とはもちろんである。In the embodiment shown in FIG. 1, the compensation of the focus error signal when the position of the light receiving spot is shifted with respect to the light receiving area divided into four parts is performed on each diagonal line in the light receiving area divided into four parts. This is achieved by simplifying the circuit configuration by adjusting the respective output levels after adding the respective light receiving outputs of the light receiving areas, but is not limited to this. Needless to say, this can be achieved by individually adjusting the level of the received light output.
【００２９】[0029]
【発明の効果】以上のとおり、本発明に因れば、４分割
の受光領域に対する受光スポットの位置ズレに対応する
オフセットを検出することが出来る。As described above, according to the present invention, it is possible to detect the offset corresponding to the positional deviation of the light receiving spot with respect to the four divided light receiving areas.
【００３０】このオフセット検出をフォーカスサーチ時
に行うようにしているので、再生開始時に毎回オフセッ
ト検出が行われ、経時変化によって受光スポットの位置
ズレが発生する場合に対応できる。Since the offset detection is performed at the time of the focus search, the offset detection is performed every time the reproduction is started, and it is possible to cope with a case where the positional deviation of the light receiving spot occurs due to a change with time.
【００３１】また、フォーカスエラー信号が「０」とな
る受光状態における４分割の受光領域における各受光出
力の出力レベルを等しくするべくフォーカスエラー信号
に関係する受光レベルのレベル調整を行っているので、
４分割の受光領域に対する受光スポットの位置ズレが生
じた場合のフォーカスエラー信号の補償が行え、前記受
光スポットの位置ズレが生じた場合でも信号記録媒体の
信号面に正しく光ビームの焦点位置を一致させるべくフ
ォーカス制御を行えるようにすることが出来る。In addition, since the level of the light receiving level related to the focus error signal is adjusted to equalize the output level of each light receiving output in the four divided light receiving areas in the light receiving state where the focus error signal is "0",
A focus error signal can be compensated for when the position of the light receiving spot shifts with respect to the light receiving area divided into four, and even when the position of the light receiving spot shifts, the focus position of the light beam correctly matches the signal surface of the signal recording medium. Focus control can be performed in order to perform this.
【図１】本発明に係る光学ヘッドのオフセット検出装置
及びオフセット補正装置を備える光学ディスク装置のフ
ォーカス制御回路部分を示す回路ブロック図である。FIG. 1 is a circuit block diagram showing a focus control circuit portion of an optical disk device including an offset detection device and an offset correction device for an optical head according to the present invention.
【図２】信号面に対して光ビームの焦点位置が前方、一
致及び後方にある状態における４分割の受光領域に対す
る受光スポットの位置ズレを説明する説明図である。FIG. 2 is an explanatory diagram for explaining a positional shift of a light receiving spot with respect to a four-divided light receiving area in a state where a focal position of a light beam is forward, coincident, and rearward with respect to a signal surface.
１ 光検出器（４分割の受光領域） ６，７ アンプ ８ フォーカスエラー信号生成回路 ９ レベル検出回路 １０ ゲイン調整回路 Reference Signs List 1 photodetector (four-division light receiving area) 6, 7 amplifier 8 focus error signal generation circuit 9 level detection circuit 10 gain adjustment circuit
Claims (3)
分割線により分割された４分割の受光領域により受光す
る光検出器を備え、前記各受光領域におけるそれぞれ対
角線上に配置される各受光領域の各受光出力をそれぞれ
加算した各加算出力レベルの差を検出することにより信
号記録媒体の信号面に対する光ビームの焦点誤差に対応
するフォーカスエラー信号が得られる光学ヘッドにおい
て、前記フォーカスエラー信号が「０」となる前記４分
割の受光領域に投影される受光スポットの受光状態にお
ける前記４分割の受光領域における各受光出力の出力レ
ベルを検出して前記４分割の受光領域に対する受光スポ
ットの位置ズレに対応するオフセットを検出するように
したことを特徴とする光学ヘッドのオフセット検出装
置。1. A photodetector for receiving an astigmatism-imparted light beam by four divided light receiving areas divided by a cross-shaped dividing line, wherein each of the light receiving areas is arranged on a diagonal line. An optical head, wherein a focus error signal corresponding to a focus error of a light beam with respect to a signal surface of a signal recording medium is obtained by detecting a difference between respective added output levels obtained by adding respective light receiving outputs of a light receiving area. In the light receiving state of the light receiving spot projected on the four divided light receiving areas, the output level of each light receiving output in the four divided light receiving areas is detected, and the position of the light receiving spot with respect to the four divided light receiving areas is detected. An offset detecting device for an optical head, wherein an offset corresponding to the displacement is detected.
物レンズをフォーカス方向に駆動するフォーカスサーチ
時に前記フォーカスエラー信号が「０」となる受光状態
を検出し、その受光状態における４分割の受光領域の各
受光出力の出力レベルを検出するようにしたことを特徴
とする請求項１記載の光学ヘッドのオフセット検出装
置。2. A light receiving state in which the focus error signal is "0" is detected during a focus search in which an objective lens is driven in a focus direction to be introduced into a focus servo area, and each of the four divided light receiving areas in the light receiving state is detected. 2. The optical head offset detecting device according to claim 1, wherein an output level of a light receiving output is detected.
の受光ズレ検出装置を備える受光ズレ補正装置であっ
て、フォーカスエラー信号が「０」となる受光状態にお
ける４分割の受光領域における各受光出力の出力レベル
を等しくするべくフォーカスエラー信号に関係する受光
レベルのレベル調整を行ってオフセット補正を行うこと
を特徴とする光学ヘッドのオフセット補正装置。3. A light-receiving displacement correcting device comprising the light-receiving displacement detecting device for an optical head according to claim 1, wherein each of the four divided light receiving regions in a light receiving state in which a focus error signal is “0”. An offset correction device for an optical head, wherein the offset correction is performed by adjusting the level of a light reception level related to a focus error signal so as to make the output level of a light reception output equal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000214663A JP2002032924A (en) | 2000-07-14 | 2000-07-14 | Offset detector and compensator for optical head |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000214663A JP2002032924A (en) | 2000-07-14 | 2000-07-14 | Offset detector and compensator for optical head |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2002032924A true JP2002032924A (en) | 2002-01-31 |
Family
ID=18710195
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2000214663A Pending JP2002032924A (en) | 2000-07-14 | 2000-07-14 | Offset detector and compensator for optical head |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2002032924A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007012200A (en) * | 2005-07-01 | 2007-01-18 | Sanyo Electric Co Ltd | Light receiving output controller of photodetector in optical pickup device |
| JP2007164847A (en) * | 2005-12-09 | 2007-06-28 | Sanyo Electric Co Ltd | Optical disk device and optical pickup device |
| US7551529B2 (en) | 2005-08-22 | 2009-06-23 | Funai Electric Co., Ltd. | Optical disc apparatus |
-
2000
- 2000-07-14 JP JP2000214663A patent/JP2002032924A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007012200A (en) * | 2005-07-01 | 2007-01-18 | Sanyo Electric Co Ltd | Light receiving output controller of photodetector in optical pickup device |
| US7365296B2 (en) | 2005-07-01 | 2008-04-29 | Sanyo Electric Co., Ltd. | Light reception output controlling apparatus of photo detector in optical pickup unit |
| US7551529B2 (en) | 2005-08-22 | 2009-06-23 | Funai Electric Co., Ltd. | Optical disc apparatus |
| JP2007164847A (en) * | 2005-12-09 | 2007-06-28 | Sanyo Electric Co Ltd | Optical disk device and optical pickup device |
| JP4601546B2 (en) * | 2005-12-09 | 2010-12-22 | 三洋電機株式会社 | Optical disk device |
| US7907501B2 (en) | 2005-12-09 | 2011-03-15 | Sanyo Electric Co., Ltd. | Optical disc apparatus and optical pickup unit |
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