JP2003051131A - Detector for focus error signal - Google Patents
Detector for focus error signalInfo
- Publication number
- JP2003051131A JP2003051131A JP2001238334A JP2001238334A JP2003051131A JP 2003051131 A JP2003051131 A JP 2003051131A JP 2001238334 A JP2001238334 A JP 2001238334A JP 2001238334 A JP2001238334 A JP 2001238334A JP 2003051131 A JP2003051131 A JP 2003051131A
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- JP
- Japan
- Prior art keywords
- signal
- focus error
- difference
- differential
- detection
- Prior art date
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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、光ディスクに記録
された情報を読み出して再生する光ディスク装置の光ピ
ックアップ装置の制御に用いられるフォーカス誤差信号
検出装置の改良に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a focus error signal detecting device used for controlling an optical pickup device of an optical disc device for reading and reproducing information recorded on an optical disc.
【０００２】[0002]
【従来の技術】従来の技術は、例えば、実開平１−１５
１４２０号公報に記載されているように、田字状に配置
された４分割光検出器の対角線方向に配置された２組の
光検出素子のそれぞれの検出電圧の和の出力の差分によ
ってフォーカス誤差信号を検出する非点収差法によるフ
ォーカス誤差信号検出装置において、４分割光検出器の
縦方向に配置された２組の光検出素子のそれぞれの検出
電圧の和の出力の差分の信号と、４分割光検出器の横方
向に配置された２組の光検出素子のそれぞれの検出電圧
の和の出力の差分の信号とを、レベルと極性とを調整し
て、対角線方向に配置された２組の光検出素子のそれぞ
れの検出電圧の和の出力の差分によるフォーカス誤差信
号に加算して、トラックずれの影響や再生トラック若し
くは隣接トラックの情報の混入によるフォーカス誤差信
号の変動を抑制するようにしたものがあった。2. Description of the Related Art A conventional technique is, for example, an actual Kaihei 1-15.
As described in Japanese Patent Publication No. 1420, the focus error is caused by the difference in the output of the sum of the detection voltages of the two sets of photodetector elements diagonally arranged in the four-division photodetector arranged in the shape of a letter. In a focus error signal detection device using an astigmatism method for detecting a signal, a signal of a difference between outputs of sums of detection voltages of two sets of photodetection elements arranged in a vertical direction of a four-division photodetector and a signal of 4 The level difference and the signal of the difference of the output of the sum of the detection voltages of the two sets of photodetection elements arranged in the lateral direction of the split photodetector are adjusted in the diagonal direction, and the two sets are arranged in the diagonal direction. This is added to the focus error signal due to the difference in the output of the sum of the detection voltages of the respective photodetector elements to suppress the influence of the track deviation and the fluctuation of the focus error signal due to the mixing of the information of the reproduction track or the adjacent track. It was something that was so.
【０００３】[0003]
【発明が解決しようとする課題】しかしながら、上記従
来の技術では、４分割光検出器の縦方向に配置された２
組の光検出素子のそれぞれの検出電圧の和の出力の差分
の信号と、４分割光検出器の横方向に配置された２組の
光検出素子のそれぞれの検出電圧の和の出力の差分の信
号とを、レベルと極性を調整して、対角線方向に配置さ
れた２組の光検出素子のそれぞれの検出電圧の和の出力
の差分によるフォーカス誤差信号に加算して、トラック
ずれの影響や再生トラック若しくは隣接トラックの情報
の混入によるフォーカス誤差信号の変動を抑制すること
ができたが、４分割光検出器の対角線方向に配置された
光検出素子の検出電圧のずれを調整することができない
ため、光検出素子の検出電圧がずれている場合、レーザ
光ビームの焦点が光ディスクの面上に形成されたピット
に合っているにも拘わらず、レーザ光ビームの焦点が光
ディスクの面上に形成されたピットから外れ、安定した
フォーカスサーボ制御を行うことができないという不都
合があった。However, in the above-mentioned conventional technique, two photodetectors arranged in the vertical direction of the four-division photodetector are used.
Of the difference signal of the sum output of the respective detection voltages of the pair of photodetection elements and the difference output of the sum of the detection voltages of the two sets of photodetection elements arranged in the lateral direction of the four-division photodetector. The signal and the level and polarity are adjusted and added to the focus error signal due to the difference in the output of the sum of the detection voltages of the two sets of photo-detecting elements arranged in the diagonal direction, and the influence of track deviation and reproduction The fluctuation of the focus error signal due to the mixing of the information of the track or the adjacent track could be suppressed, but the deviation of the detection voltage of the photodetection elements arranged in the diagonal direction of the four-division photodetector cannot be adjusted. , When the detection voltage of the photodetector is deviated, the focus of the laser light beam is on the surface of the optical disc, even though the focus of the laser light beam is on the pit formed on the surface of the optical disc. Off the made pits, there is a disadvantage that it is not possible to perform stable focus servo control.
【０００４】周知のように、光ディスクの面上に形成さ
れたピットからのレーザ光の反射光は、光ピックアップ
に内蔵された４分割光検出器１によって検出される。非
点収差法によるフォーカス誤差信号ＦＥは、４分割光検
出器の対角線上に配置された２組の光検出素子の検出電
圧Ａ、Ｃの和の信号と、検出電圧Ｂ、Ｄの和の信号との
差分の信号、即ちＦＥ＝（Ａ＋Ｃ）−（Ｂ＋Ｄ）として
得られる。As is well known, the reflected light of the laser light from the pits formed on the surface of the optical disc is detected by a four-division photodetector 1 built in the optical pickup. The focus error signal FE by the astigmatism method is a signal of the sum of the detection voltages A and C of two pairs of photodetector elements arranged on the diagonal line of the four-division photodetector and a signal of the sum of the detection voltages B and D. It is obtained as a signal of the difference between FE and (FE) = (A + C)-(B + D).
【０００５】レーザ光ビームの焦点が光ディスクの面上
に形成されたピットに合っている場合、４分割光検出器
１に入射するレーザ光の反射光のスポット１ａの状態
は、図３の（ｂ）に示すように、各光検出素子に入射す
るレーザ光の反射光の光量が同じとなり、各光検出素子
の検出電圧が同じ場合、フォーカス誤差信号ＦＥが０と
なる。When the laser light beam is focused on the pit formed on the surface of the optical disk, the state of the reflected light spot 1a of the laser light incident on the four-division photodetector 1 is as shown in FIG. ), The focus error signal FE becomes 0 when the amount of reflected light of the laser light incident on each photodetecting element is the same and the detection voltage of each photodetecting element is the same.
【０００６】また、レーザ光ビームの焦点が光ディスク
の面上に形成されたピットより近すぎる場合（図３の
（ａ）参照）、或いはレーザ光ビームの焦点が光ディス
クの面上に形成されたピットより遠すぎる場合（図３の
（ｃ）参照）、各光検出素子に入射するレーザ光の反射
光の光量に差が生じ、Ａ＋Ｃ＜Ｂ＋Ｄ、或いはＡ＋Ｃ＞
Ｂ＋Ｄとなり、フォーカスサーボは、フォーカス誤差信
号ＦＥが０となるように、光ピックアップのフォーカス
アクチュエータを制御して、レーザ光ビームの焦点を光
ディスクの面上に形成されたピットに合わせるようにす
る。Further, when the focus of the laser light beam is too close to the pit formed on the surface of the optical disc (see FIG. 3A), or the focus of the laser light beam is formed on the pit of the optical disc. When the distance is too far (see (c) of FIG. 3), there is a difference in the amount of reflected light of the laser light incident on each photodetecting element, and A + C <B + D or A + C>.
B + D, and the focus servo controls the focus actuator of the optical pickup so that the focus error signal FE becomes 0, so that the focus of the laser light beam is focused on the pit formed on the surface of the optical disc.
【０００７】ところが、何らかの原因でレーザ光ビーム
の焦点が光ディスクの面上に形成されたピットに合って
いるにも拘わらず、４分割光検出器の光検出素子の検出
電圧にずれがある場合、例えば、取り付け誤差によって
４分割光検出器への光ビームの反射光のスポットがずれ
た場合（図３の（ｄ）参照）、或いは４分割光検出器の
光検出素子の特性にずれがある場合（図示せず）、４分
割光検出器の光検出素子の検出電圧にずれが生じる。However, if the focus of the laser light beam is aligned with the pit formed on the surface of the optical disk for some reason, but there is a deviation in the detection voltage of the photodetection element of the four-division photodetector, For example, when the spot of the reflected light of the light beam to the four-division photodetector is deviated due to the mounting error (see (d) of FIG. 3), or when the characteristics of the photodetection element of the four-division photodetector are deviated. (Not shown) A deviation occurs in the detection voltage of the photodetection element of the 4-split photodetector.
【０００８】４分割光検出器の各光検出素子の出力電圧
Ａ、Ｂ、Ｃ、Ｄにずれがあり、検出電圧ＡとＣとにΔＰ
の検出電圧のずれがあり、検出電圧ＢとＤとにΔＱの検
出電圧のずれがある場合、レーザ光ビームの焦点が光デ
ィスクの面上に形成されたピットに合っているにも拘わ
らず、非点収差法によって検出されたフォーカス誤差信
号ＦＥは、ＦＥ＝ΔＰ−ΔＱとなり、ΔＰ＝ΔＱでない
場合、ＦＥ＝０とならず、レーザ光ビームの焦点が光デ
ィスクの面上に形成されたピットに合っていないと判断
され、フォーカスサーボはこれを補正するように光ピッ
クアップのフォーカスアクチュエータを制御するため、
レーザ光ビームの焦点が光ディスクの面上に形成された
ピットから外れることになる。There is a deviation in the output voltages A, B, C, D of the respective photodetection elements of the four-division photodetector, and the detection voltages A and C are ΔP.
If there is a deviation in the detection voltage of ΔQ and there is a deviation in the detection voltage of ΔQ between the detection voltages B and D, the laser light beam is focused on the pit formed on the surface of the optical disc, The focus error signal FE detected by the point aberration method becomes FE = ΔP−ΔQ, and when ΔP = ΔQ is not satisfied, FE = 0 does not hold and the focus of the laser light beam is aligned with the pit formed on the surface of the optical disc. The focus servo controls the focus actuator of the optical pickup to correct this.
The focus of the laser light beam deviates from the pit formed on the surface of the optical disc.
【０００９】本発明は上記の点に鑑みてなされたもので
あり、４分割光検出器の光検出素子の検出電圧のずれを
補正して、光検出素子の検出電圧にずれがある場合で
も、レーザ光ビームの焦点が光ディスクの面上に形成さ
れたピットに合っている場合、レーザ光ビームの焦点が
光ディスクの面上に形成されたピットから外れることな
く、安定したフォーカスサーボ制御を行うことができる
ようにしようとするものである。The present invention has been made in view of the above points, and corrects the deviation of the detection voltage of the photodetection element of the four-division photodetector so that even if the detection voltage of the photodetection element has a deviation, When the focus of the laser light beam is aligned with the pit formed on the surface of the optical disc, the focus of the laser light beam does not deviate from the pit formed on the surface of the optical disc, and stable focus servo control can be performed. It tries to be able to do it.
【００１０】[0010]
【課題を解決するための手段】上記目的を達成するため
本発明においては、田字状に配置された４分割光検出器
の対角線方向に配置された２組の光検出素子のそれぞれ
の検出電圧の和の信号の差分によってフォーカス誤差信
号を検出するフォーカス誤差信号検出装置において、４
分割光検出器の対角線方向に配置された第１、第２の光
検出素子の検出電圧の和の信号を出力する第１の加算増
幅手段と、前記４分割光検出器の対角線方向に配置され
た第３、第４の光検出素子の検出電圧の和の信号を出力
する第２の加算増幅手段と、前記第１、第２の光検出素
子の検出電圧の差の信号を出力する第１の差動増幅手段
と、前記第３、第４の光検出素子の検出電圧の差の信号
を出力する第２の差動増幅手段と、前記第１、第２の差
動増幅手段の出力信号によって、前記第１、第２の加算
増幅手段のそれぞれの出力信号を補正する第１、第２の
補正手段と、前記第１、第２の補正手段によって補正さ
れた前記第１、第２の加算増幅手段の出力信号を差分し
てフォーカス誤差信号を出力する第３の差動増幅手段と
を備え、４分割光検出器の対角線上に配置された光検出
素子の検出電圧のずれを補正するようにする。In order to achieve the above object, in the present invention, the detection voltage of each of the two sets of photo-detecting elements arranged diagonally of the four-division photo-detector arranged in a T-shape. In the focus error signal detection device for detecting the focus error signal by the difference of the sum signal of
First summing amplification means for outputting a signal of the sum of the detection voltages of the first and second photodetector elements arranged in the diagonal direction of the split photodetector, and arranged in the diagonal direction of the four-split photodetector. The second addition amplification means for outputting the signal of the sum of the detection voltages of the third and fourth photodetection elements and the first for outputting the signal of the difference of the detection voltages of the first and second photodetection elements. Differential amplifying means, a second differential amplifying means for outputting a signal of a difference between detection voltages of the third and fourth photodetecting elements, and output signals of the first and second differential amplifying means. According to the first and second correction means for correcting the respective output signals of the first and second summing amplification means, and the first and second correction means corrected by the first and second correction means. And a third differential amplifier that outputs a focus error signal by differentiating the output signals of the addition amplifier. The deviation of the output unit of the detected voltage of the arrangement photodetection element diagonally so as to correct.
【００１１】これらの手段により、４分割光検出器の光
検出素子の検出電圧にずれがある場合でも、レーザ光ビ
ームの焦点が光ディスクの面上に形成されたピットに合
っている場合、レーザ光ビームの焦点が光ディスクの面
上に形成されたピットから外れることなく、安定したフ
ォーカスサーボ制御を行うことができる。By these means, even if there is a deviation in the detection voltage of the photodetection element of the four-division photodetector, if the focus of the laser light beam is on the pit formed on the surface of the optical disk, the laser light The focus of the beam does not deviate from the pit formed on the surface of the optical disc, and stable focus servo control can be performed.
【００１２】[0012]
【発明の実施の形態】以下、適宜図面を参照しながら本
発明の実施の形態を詳述する。図１は本発明の実施の形
態に係るフォーカス誤差信号検出装置の構成を示すブロ
ック図であり、図２は本発明の実施の形態に係る他のフ
ォーカス誤差信号検出装置の構成を示すブロック図であ
る。BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below in detail with reference to the drawings as appropriate. FIG. 1 is a block diagram showing a configuration of a focus error signal detection device according to an embodiment of the present invention, and FIG. 2 is a block diagram showing a configuration of another focus error signal detection device according to an embodiment of the present invention. is there.
【００１３】まず、図１の本発明の実施の形態に係るフ
ォーカス誤差信号検出装置の構成を示すブロック図を基
に説明する。First, a description will be given based on the block diagram showing the configuration of the focus error signal detection apparatus according to the embodiment of the present invention in FIG.
【００１４】４分割光検出器１の対角線上に配置された
一対の光検出素子の検出電圧Ａ、Ｃは、加算増幅器２に
よって加算され、加算された和の信号が差動増幅器７に
送られ、４分割光検出器１の対角線上に配置された他の
１対の光検出素子の検出電圧Ｂ、Ｄは、加算増幅器３に
よって加算され、加算された和の信号が加算増幅器８に
送られる。The detection voltages A and C of a pair of photo-detecting elements arranged on the diagonal line of the four-division photo-detector 1 are added by a summing amplifier 2 and the summed signal is sent to a differential amplifier 7. The detection voltages B and D of the other pair of photodetector elements arranged on the diagonal line of the four-division photodetector 1 are added by the adding amplifier 3 and the added sum signal is sent to the adding amplifier 8. .
【００１５】また、４分割光検出器１の対角線上に配置
された一対の光検出素子の検出電圧Ａ、Ｃは、差動絶対
値増幅器４によって差分され、４分割光検出器の対角線
上に配置された他の１対の光検出素子の検出電圧Ｂ、Ｄ
は、差動絶対値増幅器５によって差分され、差分された
それぞれの検出電圧の差の信号が、差動減衰器６に送ら
れる。Further, the detection voltages A and C of the pair of photodetection elements arranged on the diagonal line of the 4-division photodetector 1 are differentiated by the differential absolute value amplifier 4, and are on the diagonal line of the 4-division photodetector. Detection voltage B, D of the other pair of photodetector elements arranged
Is sent to the differential attenuator 6 by the differential absolute value amplifier 5.
【００１６】そして、差動減衰器６に送られた検出電圧
の差の信号は、差動減衰器６によって差分され、差分さ
れた信号のレベルが半減されて、加算増幅器２によって
加算された検出電圧Ａ、Ｃの和の信号と、加算増幅器３
によって加算された検出電圧Ｂ、Ｄの和の信号とを補正
する補正信号として、差動増幅器７と加算増幅器８とに
送られる。The detection voltage difference signal sent to the differential attenuator 6 is subtracted by the differential attenuator 6, the level of the differentiated signal is halved, and the summing amplifier 2 adds the detected signal. Signal of sum of voltages A and C and summing amplifier 3
Is sent to the differential amplifier 7 and the addition amplifier 8 as a correction signal for correcting the signal of the sum of the detection voltages B and D added by.
【００１７】差動減衰器６から送られた補正信号は、差
動増幅器７によって、加算増幅器２によって加算された
検出電圧Ａ、Ｃの和の信号に極性が反転されて加算さ
れ、差動減衰器６から送られた補正信号は、加算増幅器
８によって、加算増幅器３によって加算された検出電圧
Ｂ、Ｄの和の信号に加算され、差動増幅器９に送られ
る。The correction signal sent from the differential attenuator 6 is added by the differential amplifier 7 to the signal of the sum of the detection voltages A and C added by the addition amplifier 2 with its polarity inverted, and the differential attenuation. The correction signal sent from the device 6 is added to the signal of the sum of the detection voltages B and D added by the adding amplifier 3 by the adding amplifier 8 and sent to the differential amplifier 9.
【００１８】そして、補正信号が加算された検出電圧
Ａ、Ｃの和の信号と補正信号が加算された検出電圧Ｂ、
Ｄの和の信号とが、差動増幅器９によって差分され、光
検出素子の検出電圧のずれが補正されたフォーカス誤差
信号ＦＥがフォーカスサーボ（図示せず）に送られる。
フォーカスサーボは、差動増幅器９から送られたフォー
カス誤差信号ＦＥが０となるように、光ピックアップの
フォーカスアクチュエータを制御し、レーザ光ビームの
焦点が常に光ディスクの面上に形成されたピットに合う
ように調整する。Then, a signal of the sum of the detection voltages A and C to which the correction signal is added and a detection voltage B to which the correction signal is added,
The signal of the sum of D is differentiated by the differential amplifier 9, and the focus error signal FE in which the deviation of the detection voltage of the photodetector is corrected is sent to the focus servo (not shown).
The focus servo controls the focus actuator of the optical pickup so that the focus error signal FE sent from the differential amplifier 9 becomes 0, and the focus of the laser light beam is always aligned with the pit formed on the surface of the optical disc. To adjust.
【００１９】また、図２の本発明の実施の形態に係る他
のフォーカス誤差信号検出装置の構成を示すブロック図
を基に説明する。Further, a description will be given based on a block diagram showing the configuration of another focus error signal detection apparatus according to the embodiment of the present invention in FIG.
【００２０】４分割光検出器１の対角線上に配置された
一対の光検出素子の検出電圧Ａ、Ｃは、加算増幅器１１
によって加算され、加算された和の信号が差動増幅器１
５に送られ、４分割光検出器１の対角線上に配置された
他の１対の光検出素子の検出電圧Ｂ、Ｄは、加算増幅器
１２によって加算され、加算された和の信号が差動増幅
器１６に送られる。The detection voltages A and C of a pair of photo-detecting elements arranged on the diagonal of the four-division photo-detector 1 are summing amplifiers 11.
Are added by the differential amplifier 1 and the added sum signals are added.
5, the detection voltages B and D of the other pair of photodetector elements arranged on the diagonal line of the 4-division photodetector 1 are added by the adding amplifier 12, and the added sum signal is differential. It is sent to the amplifier 16.
【００２１】また、４分割光検出器１の対角線上に配置
された一対の光検出素子の検出電圧Ａ、Ｃは、差動絶対
値増幅器１３によって差分され、差分された検出電圧
Ａ、Ｃの差の信号が、加算増幅器１１によって加算され
た検出電圧Ａ、Ｃの和の信号を補正する補正信号とし
て、差動増幅器１５に送られ、４分割光検出器の対角線
上に配置された他の１対の光検出素子の検出電圧Ｂ、Ｄ
は、差動絶対値増幅器１４によって差分され、差分され
た検出電圧Ｂ、Ｄの差の信号が、加算増幅器１２によっ
て加算された検出電圧Ａ、Ｃの和の信号を補正する補正
信号として、差動増幅器１６に送られる。Further, the detection voltages A and C of the pair of photodetection elements arranged on the diagonal line of the four-division photodetector 1 are differentiated by the differential absolute value amplifier 13, and the detected voltages A and C are differentiated. The difference signal is sent to the differential amplifier 15 as a correction signal for correcting the signal of the sum of the detection voltages A and C added by the addition amplifier 11, and is sent to the other of the diagonal lines of the four-division photodetector. Detection voltage B, D of a pair of photo-detecting elements
Is the difference signal of the difference between the detection voltages B and D, which is difference by the differential absolute value amplifier 14, and is the difference signal as a correction signal for correcting the sum signal of the detection voltages A and C added by the addition amplifier 12. It is sent to the dynamic amplifier 16.
【００２２】差動絶対値増幅器１３から送られた補正信
号は、差動増幅器１５によって、加算増幅器１１によっ
て加算された検出電圧Ａ、Ｃの和の信号に極性を反転し
て加算され、検出電圧Ａ、Ｃの和の信号の光検出素子の
検出電圧のずれが補正される。また、差動絶対値増幅器
１４から送られた補正信号は、差動増幅器１６によっ
て、加算増幅器１２から送られた検出電圧ＢとＤとの和
の信号に極性を反転して加算され、検出電圧Ｂ、Ｄの和
の信号の光検出素子の検出電圧のずれが補正される。The correction signal sent from the differential absolute value amplifier 13 is inverted by the differential amplifier 15 and added to the signal of the sum of the detection voltages A and C added by the addition amplifier 11, and the detection voltage is added. The deviation of the detection voltage of the photodetector element of the signal of the sum of A and C is corrected. Further, the correction signal sent from the differential absolute value amplifier 14 is inverted by the differential amplifier 16 and added to the signal of the sum of the detection voltages B and D sent from the adding amplifier 12, with the detected voltage The deviation of the detection voltage of the photodetector element of the signal of the sum of B and D is corrected.
【００２３】そして、差動増幅器１５によって補正され
た検出電圧Ａ、Ｃの和の信号と差動増幅器１６によって
補正された検出電圧Ｂ、Ｄの和の信号とが、差動増幅器
１７によって差分され、フォーカス誤差信号ＦＥがフォ
ーカスサーボ（図示せず）に送られる。フォーカスサー
ボは、差動増幅器１７から送られたフォーカス誤差信号
ＦＥが０となるように、光ピックアップのフォーカスア
クチュエータを制御して、レーザ光ビームの焦点が常に
光ディスクの面上に形成されたピットに合うように調整
する。The sum signal of the detection voltages A and C corrected by the differential amplifier 15 and the sum signal of the detection voltages B and D corrected by the differential amplifier 16 are differentiated by the differential amplifier 17. , The focus error signal FE is sent to the focus servo (not shown). The focus servo controls the focus actuator of the optical pickup so that the focus error signal FE sent from the differential amplifier 17 becomes 0, and the focus of the laser light beam is always on the pit formed on the surface of the optical disc. Adjust to fit.
【００２４】以上、本発明の実施の形態について詳述し
たが、本発明はこれに限らず、当業者の通常の知識の範
囲内でその変形や改良が可能である。例えば、図２を図
４に示すように変形することができる。Although the embodiment of the present invention has been described in detail above, the present invention is not limited to this, and modifications and improvements can be made within the scope of ordinary knowledge of those skilled in the art. For example, FIG. 2 can be modified as shown in FIG.
【００２５】[0025]
【発明の効果】以上説明してきたように、本発明による
フォーカス誤差信号検出装置によれば、４分割光検出器
の対角線方向に配置された２組の光検出素子のそれぞれ
の検出電圧の差の信号によって、それぞれの検出電圧の
和の信号を補正し、補正されたそれぞれの検出電圧の和
の信号を差分してフォーカス誤差信号を検出することに
よって、光検出素子の検出電圧のずれを補正することが
できる。このことにより、４分割光検出器の光検出素子
の検出電圧にずれがある場合でも、レーザ光ビームの焦
点が光ディスクの面上に形成されたピットに合っている
場合、レーザ光ビームの焦点が光ディスクの面上に形成
されたピットから外れることなく、安定したフォーカス
サーボ制御を行うことができる。As described above, according to the focus error signal detecting device of the present invention, the difference in the detection voltage between the two sets of photodetecting elements arranged in the diagonal direction of the four-division photodetector can be obtained. A signal is used to correct the sum signal of the respective detection voltages and the corrected sum signal of the detection voltages is subtracted to detect the focus error signal, thereby correcting the deviation of the detection voltage of the photodetector element. be able to. As a result, even if there is a deviation in the detection voltage of the photodetection element of the four-division photodetector, if the focus of the laser light beam is aligned with the pit formed on the surface of the optical disc, the focus of the laser light beam will be Stable focus servo control can be performed without deviating from the pits formed on the surface of the optical disc.
【００２６】請求項１記載の発明に係るフォーカス誤差
信号検出装置は、４分割光検出器の対角線方向に配置さ
れた２組の光検出素子のそれぞれの検出電圧の差の信号
の差分の信号を、レベルを半減し極性を調整して、それ
ぞれの検出電圧の和の信号に加算して補正し、補正され
たそれぞれの検出電圧の和の信号を差分してフォーカス
誤差信号を検出するようにしている。In the focus error signal detecting device according to the first aspect of the present invention, the difference signal of the difference between the detection voltages of the two photodetector elements arranged in the diagonal direction of the four-division photodetector is detected. , The level is halved, the polarity is adjusted, the signal of the sum of the respective detection voltages is added and corrected, and the focus error signal is detected by subtracting the signal of the sum of the corrected respective detection voltages. There is.
【００２７】請求項２記載の発明に係るフォーカス誤差
信号検出装置は、４分割光検出器の対角線方向に配置さ
れた２組の光検出素子のそれぞれの検出電圧の差の信号
によって、それぞれの検出電圧の和の信号を補正して、
補正されたそれぞれの検出電圧の和の信号を差分してフ
ォーカス誤差信号を検出するようにしている。In the focus error signal detecting device according to the second aspect of the present invention, each of the detection signals is detected by a signal of a difference between detection voltages of two sets of photodetecting elements arranged in a diagonal direction of the four-division photodetector. Correct the signal of the sum of the voltage,
The focus error signal is detected by making a difference between the signals of the corrected detection voltages.
【００２８】請求項３記載の発明に係るフォーカス誤差
信号検出装置は、４分割光検出器の対角線上に配置され
た２組の光検出素子のそれぞれの検出電圧の差の信号の
差分の信号を、レベルを半減し極性を調整して、それぞ
れの検出電圧の和の信号に加算して、４分割光検出器の
光検出素子の検出電圧のずれを補正するようにしてい
る。According to a third aspect of the present invention, there is provided a focus error signal detecting device which detects a difference signal of detection voltage differences of two sets of photodetecting elements arranged diagonally of a four-division photodetector. , The level is halved, the polarity is adjusted, and the signal is added to the signal of the sum of the respective detection voltages to correct the deviation of the detection voltage of the photodetection element of the four-division photodetector.
【００２９】請求項４記載の発明に係るフォーカス誤差
信号検出装置は、４分割光検出器の対角線上に配置され
た２組の光検出素子のそれぞれの検出電圧の差の信号
を、極性を反転して、それぞれの検出電圧の和の信号に
加算して、４分割光検出器の対角線上に配置された光検
出素子の検出電圧のずれを補正するようにしている。In the focus error signal detection device according to the present invention, the polarity of the signal of the difference between the detection voltages of the two sets of photodetection elements arranged on the diagonal line of the four-division photodetector is inverted. Then, it is configured to be added to the signal of the sum of the respective detection voltages to correct the deviation of the detection voltage of the photodetection elements arranged on the diagonal of the four-division photodetector.
【図１】 本発明の実施の形態に係るフォーカス誤差信
号検出装置の構成を示すブロック図である。FIG. 1 is a block diagram showing a configuration of a focus error signal detection device according to an embodiment of the present invention.
【図２】 本発明の実施の形態に係る他のフォーカス誤
差信号検出装置の構成を示すブロック図である。FIG. 2 is a block diagram showing a configuration of another focus error signal detection device according to the embodiment of the present invention.
【図３】 ４分割光検出器に入射するレーザ光の反射光
のスポットの状態を示す説明図である。FIG. 3 is an explanatory diagram showing a state of a spot of reflected light of laser light that is incident on a four-division photodetector.
【図４】 本発明のフォーカス誤差信号検出装置の変形
例を示すブロック図である。FIG. 4 is a block diagram showing a modified example of the focus error signal detection device of the present invention.
１ ４分割光検出器
１ａ 反射光のスポット
２、３、８、１１、１２、２１、２２ 加算増幅器
４、５、１３、１４、２３、２４ 差動絶対値増幅器
７、９、１５、１６、１７、２５、２６、２７ 差動増
幅器
６ 差動減衰器1 4-split photodetector 1a Spots of reflected light 2, 3, 8, 11, 12, 21, 22 Summing amplifiers 4, 5, 13, 14, 23, 24 Differential absolute value amplifiers 7, 9, 15, 16, 17, 25, 26, 27 Differential amplifier 6 Differential attenuator
Claims (4)
角線方向に配置された２組の光検出素子のそれぞれの検
出電圧の和の信号の差分によってフォーカス誤差信号を
検出するフォーカス誤差信号検出装置において、４分割
光検出器の対角線方向に配置された第１、第２の光検出
素子の検出電圧の和の信号を出力する第１の加算増幅手
段と、前記４分割光検出器の対角線方向に配置された第
３、第４の光検出素子の検出電圧の和の信号を出力する
第２の加算増幅手段と、前記第１、第２の光検出素子の
検出電圧の差の信号を出力する第１の差動増幅手段と、
前記第３、第４の光検出素子の検出電圧の差の信号を出
力する第２の差動増幅手段と、前記第１、第２の差動増
幅手段の出力信号を差分し、差分した信号のレベルを半
減して出力する差動減衰手段と、前記差動減衰手段の出
力信号を、極性を反転して、前記第１の加算増幅手段の
出力信号に加算する第１の補正手段と、前記差動減衰手
段の出力信号を前記第２の加算増幅手段の出力信号に加
算する第２の補正手段と、前記第１、第２の補正手段に
よって補正された前記第１、第２の加算増幅手段の出力
信号を差分してフォーカス誤差信号を出力する第３の差
動増幅手段とを備え、４分割光検出器の対角線上に配置
された光検出素子の検出電圧のずれを補正するようにし
たことを特徴とするフォーカス誤差信号検出装置。1. A focus error for detecting a focus error signal based on a difference between signals of sums of detection voltages of two sets of photodetector elements diagonally arranged in a four-division photodetector arranged in a T-shape. In the signal detection device, first summing amplification means for outputting a signal of a sum of detection voltages of first and second photodetection elements arranged in a diagonal direction of the four-division photodetector, and the four-division photodetector. Of the difference between the detection voltages of the first and second photo-detecting elements and the second summing amplification means for outputting a signal of the sum of the detection voltages of the third and fourth photo-detecting elements arranged in the diagonal direction of First differential amplifying means for outputting a signal,
A signal obtained by differentiating the output signals of the second differential amplifying means and the first and second differential amplifying means, which output the signal of the difference between the detection voltages of the third and fourth photodetecting elements. And a first correcting means for inverting the polarity of the output signal of the differential attenuating means and adding it to the output signal of the first adding and amplifying means. Second correcting means for adding the output signal of the differential attenuating means to the output signal of the second adding and amplifying means, and the first and second adding operations corrected by the first and second correcting means And a third differential amplifying means for outputting a focus error signal by making a difference between the output signals of the amplifying means so as to correct the deviation of the detection voltage of the photodetecting elements arranged on the diagonal line of the four-division photodetector. A focus error signal detection device characterized in that
角線方向に配置された２組の光検出素子のそれぞれの検
出電圧の和の信号の差分によってフォーカス誤差信号を
検出するフォーカス誤差信号検出装置において、４分割
光検出器の対角線方向に配置された第１、第２の光検出
素子の検出電圧の和の信号を出力する第１の加算増幅手
段と、前記４分割光検出器の対角線方向に配置された第
３、第４の光検出素子の検出電圧の和の信号を出力する
第２の加算増幅手段と、前記第１、第２の光検出素子の
検出電圧の差の信号を出力する第１の差動増幅手段と、
前記第３、第４の光検出素子の検出電圧の差の信号を出
力する第２の差動増幅手段と、前記第１、第２の差動増
幅手段の出力信号によって、前記第１、第２の加算増幅
手段のそれぞれの出力信号を補正する第１、第２の補正
手段と、前記第１、第２の補正手段によって補正された
前記第１、第２の加算増幅手段の出力信号を差分してフ
ォーカス誤差信号を出力する第３の差動増幅手段とを備
え、４分割光検出器の対角線上に配置された光検出素子
の検出電圧のずれを補正するようにしたことを特徴とす
るフォーカス誤差信号検出装置。2. A focus error for detecting a focus error signal based on a difference between signals of respective detection voltages of two sets of photodetector elements diagonally arranged in a four-division photodetector arranged in a T-shape. In the signal detection device, first summing amplification means for outputting a signal of a sum of detection voltages of first and second photodetection elements arranged in a diagonal direction of the four-division photodetector, and the four-division photodetector. Of the difference between the detection voltages of the first and second photo-detecting elements and the second summing amplification means for outputting a signal of the sum of the detection voltages of the third and fourth photo-detecting elements arranged in the diagonal direction of First differential amplifying means for outputting a signal,
The first and second differential amplifying means for outputting a signal of the difference between the detection voltages of the third and fourth photodetecting elements and the output signals of the first and second differential amplifying means. The output signals of the first and second correction means for correcting the respective output signals of the second addition and amplification means and the output signals of the first and second addition and amplification means corrected by the first and second correction means And a third differential amplifier that outputs a focus error signal by performing a difference, and corrects the deviation of the detection voltage of the photodetection element arranged on the diagonal line of the four-division photodetector. Focus error signal detector.
の差動増幅手段の出力信号の差分の信号を、レベルを半
減し極性を反転して、前記第１の加算増幅手段の出力信
号に加算し、前記第１の加算増幅手段の出力信号を補正
する補正手段であり、前記第２の補正手段は、前記第
１、第２の差動増幅手段の出力信号の差分の信号を、レ
ベルを半減して、前記第２の加算増幅手段の出力信号に
加算し、前記第２の加算増幅手段の出力信号を補正する
補正手段であることを特徴とする請求項２記載のフォー
カス誤差信号検出装置。3. The first correction means includes the first and second correction means.
The signal of the difference between the output signals of the differential amplifying means is halved in level, the polarity is inverted, and the signal is added to the output signal of the first adding and amplifying means to correct the output signal of the first adding and amplifying means. The second correction means reduces the level of the signal of the difference between the output signals of the first and second differential amplification means by half and outputs the output signal of the second addition amplification means. The focus error signal detection device according to claim 2, wherein the focus error signal detection device is a correction unit that corrects the output signal of the second addition amplification unit.
増幅手段の出力信号を、極性を反転して、前記第１の加
算増幅手段の出力信号に加算し、前記第１の加算増幅手
段の出力信号を補正する補正手段であり、前記第２の補
正手段は、前記第２の差動増幅手段の出力信号を、極性
を反転して、前記第２の加算増幅手段の出力信号に加算
し、前記第２の加算増幅手段の出力信号を補正する補正
手段であることを特徴とする請求項２記載のフォーカス
誤差信号検出装置。4. The first correcting means reverses the polarity of the output signal of the first differential amplifying means, adds the output signal to the output signal of the first summing amplifying means, and outputs the first signal. Correction means for correcting the output signal of the addition amplification means, wherein the second correction means inverts the polarity of the output signal of the second differential amplification means and outputs the output signal of the second addition amplification means. The focus error signal detection device according to claim 2, wherein the focus error signal detection device is a correction unit that adds the signal to a signal and corrects the output signal of the second addition amplification unit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001238334A JP2003051131A (en) | 2001-08-06 | 2001-08-06 | Detector for focus error signal |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001238334A JP2003051131A (en) | 2001-08-06 | 2001-08-06 | Detector for focus error signal |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2003051131A true JP2003051131A (en) | 2003-02-21 |
Family
ID=19069269
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2001238334A Pending JP2003051131A (en) | 2001-08-06 | 2001-08-06 | Detector for focus error signal |
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| Country | Link |
|---|---|
| JP (1) | JP2003051131A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100710445B1 (en) * | 2005-07-21 | 2007-04-24 | 배연재 | Stream water quality assessment technique using benthic macroinvertebrates |
| KR100729344B1 (en) * | 2006-02-16 | 2007-06-15 | 스마텍(주) | Vehicle camera for sensing rear zone |
-
2001
- 2001-08-06 JP JP2001238334A patent/JP2003051131A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100710445B1 (en) * | 2005-07-21 | 2007-04-24 | 배연재 | Stream water quality assessment technique using benthic macroinvertebrates |
| KR100729344B1 (en) * | 2006-02-16 | 2007-06-15 | 스마텍(주) | Vehicle camera for sensing rear zone |
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