JPH1055552A - Optical pickup device - Google Patents

Optical pickup device

Info

Publication number
JPH1055552A
JPH1055552A JP8226048A JP22604896A JPH1055552A JP H1055552 A JPH1055552 A JP H1055552A JP 8226048 A JP8226048 A JP 8226048A JP 22604896 A JP22604896 A JP 22604896A JP H1055552 A JPH1055552 A JP H1055552A
Authority
JP
Japan
Prior art keywords
light receiving
light
difference signal
track
order light
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP8226048A
Other languages
Japanese (ja)
Inventor
Hiroyuki Sakuyama
宏幸 作山
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ricoh Co Ltd
Original Assignee
Ricoh Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ricoh Co Ltd filed Critical Ricoh Co Ltd
Priority to JP8226048A priority Critical patent/JPH1055552A/en
Publication of JPH1055552A publication Critical patent/JPH1055552A/en
Pending legal-status Critical Current

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  • Automatic Focus Adjustment (AREA)
  • Optical Recording Or Reproduction (AREA)
  • Optical Head (AREA)

Abstract

PROBLEM TO BE SOLVED: To provide an optical pickup device capable of obtaining a focus difference signal less in focal fluctuation and improved in reproducing resolution. SOLUTION: In this optical pickup device 10, a light receiving element 11 is divided into eight light receiving areas 11A-11H, and an operation circuit 12 operates (a+e+c+g)-(f+b+d+h) from the outputs a-h of eight light receiving areas 11A-11H, and obtains the focus difference signal Fo to output it to an adder circuit 16. The operation circuit 13 operates the sum of the outputs a-d of O-order light receiving areas 11A-11D of the light receiving element 11, and takes out the AC component of the sum signal (a+b+c+d) by an AC connection circuit 14, and constant multiplies it by a constant multiplication circuit 15 to output it to the adder circuit 16. The adder circuit 16 adds the focus difference signal Fo to the constant multiplication of the AC component of the sum signal to generate a corrective focus difference signal AFo. The corrective focus difference signal AFo is the signal correcting the focus difference signal Fo with the fluctuation by the AC component of the sum signal of the O-order light receiving areas 11A-11D, and the focal fluctuation is reduced.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【０００１】[0001]

【発明の属する技術分野】本発明は、光ピックアップ装
置に関し、詳細には、フォーカスゆらぎの少ないフォー
カス差信号を得るとともに、再生分解能を向上させた光
ピックアップ装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical pickup device, and more particularly, to an optical pickup device capable of obtaining a focus difference signal with little focus fluctuation and improving reproduction resolution.

【０００２】[0002]

【従来の技術】一般に、半導体レーザーからの光を対物
レンズによって集光させて、光情報記録媒体上に微小な
スポットを形成し、高密度な情報の記録再生を行うため
には、該スポットが光情報記録媒体上の記録面に正確に
焦点を結ぶことが必要である。そこで、従来から、非点
収差法に代表される種々の方法により、フォーカスエラ
ーの検出が行われている。2. Description of the Related Art Generally, in order to form a minute spot on an optical information recording medium by condensing light from a semiconductor laser with an objective lens, and to perform high-density information recording / reproduction, the spot is required. It is necessary to accurately focus on the recording surface on the optical information recording medium. Therefore, conventionally, focus errors have been detected by various methods represented by the astigmatism method.

【０００３】光ピックアップ装置では、図１６に示すよ
うに、光源からの光束は、対物レンズ１により光情報記
録媒体２の記録面３（図１６に実線で示す面）に収束ス
ポット４として照射され、その反射光は、図示しない波
長板等の光学部品を介して円筒レンズ５を通過して、受
光素子６上に検出スポット７として集光される。In an optical pickup device, as shown in FIG. 16, a light beam from a light source is irradiated as a convergent spot 4 on a recording surface 3 (a surface indicated by a solid line in FIG. 16) of an optical information recording medium 2 by an objective lens 1. The reflected light passes through the cylindrical lens 5 via an optical component such as a wavelength plate (not shown), and is condensed as a detection spot 7 on the light receiving element 6.

【０００４】受光素子６は、図１７〜図１９に示すよう
に、略四角形の４つの受光領域Ａ、Ｂ、Ｃ、Ｄが１点Ｐ
を中心にその回りに配置されており、受光領域Ａ、Ｃが
Ｙ方向に、受光領域Ｄ、ＢがＸ方向に、配置されてい
る。従来の非点収差法による光ピックアップ装置は、受
光素子６の各受光領域Ａ、Ｂ、Ｃ、Ｄの出力をａ、ｂ、
ｃ、ｄとすると、フォーカス信号Ｆ＝（ａ＋ｃ）−（ｂ
＋ｄ）により、フォーカスエラーを検出している。As shown in FIGS. 17 to 19, the light receiving element 6 has four substantially square light receiving areas A, B, C, and D at one point P.
, The light receiving areas A and C are arranged in the Y direction, and the light receiving areas D and B are arranged in the X direction. In the conventional optical pickup device using the astigmatism method, the outputs of the light receiving areas A, B, C, and D of the light receiving element 6 are represented by a, b, and b.
Assuming that c and d, the focus signal F = (a + c)-(b
+ D), a focus error is detected.

【０００５】そして、図１６において、光情報記録媒体
２の記録面３が、対物レンズ１の焦点位置にあるとき、
すなわち、合焦時には、光情報記録媒体２の記録面３で
反射された光は、Ｘ方向に関しては、点Ｑに、Ｙ方向に
関しては、点Ｒに焦点を持つので、受光素子６上には、
図１７に示すように、円形の検出スポット７ｅが形成さ
れる。したがって、このときの受光領域Ａ、Ｂ、Ｃ、Ｄ
の各出力は、ａ＝ｂ＝ｃ＝ｄとなり、フォーカス信号Ｆ
は、「０」（Ｆ＝０）となる。In FIG. 16, when the recording surface 3 of the optical information recording medium 2 is at the focal position of the objective lens 1,
That is, at the time of focusing, the light reflected by the recording surface 3 of the optical information recording medium 2 has a focal point at the point Q in the X direction and a point R in the Y direction. ,
As shown in FIG. 17, a circular detection spot 7e is formed. Therefore, the light receiving areas A, B, C, D at this time
Are a = b = c = d, and the focus signal F
Is “0” (F = 0).

【０００６】また、光情報記録媒体２の記録面３が、図
１６に点線３Ｎで示すように、対物レンズ１の焦点位置
よりも対物レンズ１に近い側にあるときには、記録面３
で反射された光は、点Ｑ、点ＲよりもＺ軸方向の正方向
側に焦点を持つので、受光素子６上には、図１８に示す
ように、Ｙ方向に長い縦長の楕円形の検出スポット７ｆ
が形成される。したがって、このときの受光領域Ａ、
Ｂ、Ｃ、Ｄの出力は、ａ、ｃ＞ｂ、ｄとなり、フォーカ
ス信号Ｆは、正（Ｆ＞０）である。When the recording surface 3 of the optical information recording medium 2 is closer to the objective lens 1 than the focal position of the objective lens 1 as shown by a dotted line 3N in FIG.
18 has a focal point on the positive side in the Z-axis direction with respect to the points Q and R, the light reflected on the light receiving element 6 has a vertically long elliptical shape long in the Y direction as shown in FIG. Detection spot 7f
Is formed. Therefore, the light receiving area A at this time,
The outputs of B, C, and D are a, c> b, d, and the focus signal F is positive (F> 0).

【０００７】さらに、光情報記録媒体２の記録面３が、
図１６に一点鎖線３Ｆで示すように、対物レンズ１の焦
点位置よりも対物レンズ１から遠い側にあるときには、
記録面３で反射された光は、点Ｑ、点ＲよりもＺ軸方向
の負方向側に焦点を持つので、受光素子６上には、図１
９に示すように、Ｘ方向に長い横長の楕円形の検出スポ
ット７ｇが形成される。したがって、このときの受光領
域Ａ、Ｂ、Ｃ、Ｄの出力は、ａ、ｃ＜ｂ、ｄとなり、フ
ォーカス信号Ｆは、負（Ｆ＜０）である。Further, the recording surface 3 of the optical information recording medium 2 is
As shown by the dashed line 3F in FIG. 16, when it is located farther from the objective lens 1 than the focal position of the objective lens 1,
The light reflected by the recording surface 3 has a focal point on the negative side in the Z-axis direction from the points Q and R, so that the light
As shown in FIG. 9, a horizontally long elliptical detection spot 7g long in the X direction is formed. Therefore, the outputs of the light receiving areas A, B, C, and D at this time are a, c <b, and d, and the focus signal F is negative (F <0).

【０００８】ここで、対物レンズ１が合焦位置を保った
まま光情報記録媒体２のトラックを横切る場合、フォー
カス信号Ｆは、図２０に示すように、「０」のままであ
ることが望ましいが、実際には、光情報記録媒体２に刻
まれたランドやグルーブからなるトラック溝の影響によ
り、フォーカス信号Ｆに外乱信号が重畳されて、図２１
に示すように、ゆらぎが発生する。このゆらぎが発生す
るのは、光情報記録媒体２のランド上に結像した場合と
グルーブ上に結像した場合とで、光情報記録媒体２から
の反射光の状態が異なるために、検出スポット７の強度
分布が変化し、本来の信号にゆらぎが重畳されるために
生じる現象であり、また、このゆらぎは、光情報記録媒
体２上のピット（凹部あるいは凸部）の有無によっても
生じ、合焦時（Ｆ＝０）だけでなく、デフォーカス時
（Ｆ＞０、Ｆ＜０）においても生じる。Here, when the objective lens 1 crosses the track of the optical information recording medium 2 while keeping the in-focus position, the focus signal F desirably remains "0" as shown in FIG. However, in reality, a disturbance signal is superimposed on the focus signal F due to the influence of a track groove formed of a land or a groove cut on the optical information recording medium 2, and FIG.
As shown in FIG. This fluctuation occurs when the image is formed on the land of the optical information recording medium 2 and when the image is formed on the groove, because the state of the reflected light from the optical information recording medium 2 is different. 7 is a change in intensity distribution and a fluctuation is superimposed on the original signal. This fluctuation is also caused by the presence or absence of a pit (concave or convex) on the optical information recording medium 2. This occurs not only at the time of focusing (F = 0) but also at the time of defocusing (F> 0, F <0).

【０００９】そして、このような外乱信号が、対物レン
ズ１あるいはピックアップが光情報記録媒体２の半径方
向にシークする際にフォーカス信号に重畳されると、フ
ォーカスアクチュエータが外乱により駆動される結果と
なり、騒音が発生したり、フォーカスが外れるという問
題があった。When such a disturbance signal is superimposed on a focus signal when the objective lens 1 or the pickup seeks in the radial direction of the optical information recording medium 2, the result is that the focus actuator is driven by the disturbance, There was a problem that noise was generated and the focus was lost.

【００１０】そこで、従来、このフォーカスアクチュエ
ータに加わる雑音を減少させるフォーカスサーボ装置が
提案されている（特開昭５９−１３５６４４号公報参
照）。このフォーカスサーボ装置は、フォーカスサーボ
回路の一部を構成する増幅器を利得可変増幅器として、
アクセス時に利得可変増幅器の利得を低下させることに
より、外乱信号に対するゲインを低下させて、アクセス
時の騒音を減少させている。Therefore, there has been proposed a focus servo apparatus for reducing the noise applied to the focus actuator (see Japanese Patent Application Laid-Open No. 59-135644). This focus servo device uses an amplifier constituting a part of the focus servo circuit as a variable gain amplifier,
By reducing the gain of the variable gain amplifier at the time of access, the gain at the time of access is reduced by reducing the gain for a disturbance signal.

【００１１】[0011]

【発明が解決しようとする課題】しかしながら、このよ
うな従来のフォーカスサーボ装置にあっては、アクセス
時にフォーカスサーボ回路の一部を構成する利得可変増
幅器の利得を低下さていたため、外乱信号に対するゲイ
ンを低下させることはできるが、同時に本来のフォーカ
ス差信号に対するゲインも低下させることとなり、Ｓ／
Ｎ比は改善されず、ゲインを低下させすぎると、フォー
カス誤差に追随することができず、逆にフォーカスが外
れるという問題があった。However, in such a conventional focus servo device, the gain of a variable gain amplifier constituting a part of the focus servo circuit is reduced at the time of access, so that the gain with respect to a disturbance signal is reduced. Can be reduced, but at the same time, the gain for the original focus difference signal is also reduced.
If the N ratio is not improved, and if the gain is lowered too much, there is a problem that it is not possible to follow the focus error and the focus is deviated.

【００１２】そこで、請求項１記載の発明は、受光素子
を８つの受光領域に分割し、当該８つの受光領域のう
ち、０次光を主に受光する４つの０次受光領域の受光量
をその位置関係において一方向回りにａ、ｂ、ｃ、ｄと
し、０次光と±１次光を主に受光する４つの１次受光領
域の受光量をその位置関係においてｅ、ｆ、ｇ、ｈとし
たとき、（ａ＋ｅ＋ｃ＋ｇ）−（ｆ＋ｂ＋ｄ＋ｈ）によ
りフォーカス差信号を求め、このフォーカス差信号に０
次受光領域の各受光量の和（ａ＋ｂ＋ｃ＋ｄ）の和信号
の交流成分を加算して補正フォーカス差信号を生成する
ことにより、非点収差法の揺らぎのあるフォーカス差信
号をトラックパターンを含まない０次受光領域の和信号
の交流成分で補正し、フォーカスゆらぎの少ない補正フ
ォーカス差信号を得ることができ、シーク時の外乱振幅
を低減させることのできる光ピックアップ装置を提供す
ることを目的としている。Therefore, the invention according to claim 1 divides a light receiving element into eight light receiving areas, and among the eight light receiving areas, the light receiving amounts of four zero-order light receiving areas mainly receiving the zero-order light. In the positional relationship, a, b, c, and d are defined around one direction, and the light receiving amounts of the four primary light receiving regions that mainly receive the 0th-order light and ± 1st-order light are represented by e, f, g, h, a focus difference signal is obtained from (a + e + c + g)-(f + b + d + h), and 0 is added to the focus difference signal.
By adding the AC component of the sum signal (a + b + c + d) of the respective light receiving amounts of the next light receiving area to generate a corrected focus difference signal, the focus difference signal having fluctuations in the astigmatism method can be reduced to 0 including no track pattern. It is an object of the present invention to provide an optical pickup device capable of obtaining a corrected focus difference signal with a small focus fluctuation by correcting an AC component of a sum signal of a next light receiving area and reducing a disturbance amplitude at a seek time.

【００１３】請求項２記載の発明は、受光素子を８つの
受光領域に分割し、当該８つの受光領域のうち、０次光
を主に受光する４つの０次受光領域の受光量をその位置
関係において一方向回りにａ、ｂ、ｃ、ｄとし、０次光
と±１次光を主に受光する４つの１次受光領域の受光量
をその位置関係においてｅ、ｆ、ｇ、ｈとしたとき、
（ｅ＋ｇ）−（ｆ＋ｈ）によりフォーカス差信号を求
め、このフォーカス差信号に０次受光領域の各受光量の
和（ａ＋ｂ＋ｃ＋ｄ）の和信号の交流成分を加算して補
正フォーカス差信号を生成することにより、簡単な回路
構成で非点収差法の揺らぎのあるフォーカス差信号をト
ラックパターンを含まない０次受光領域の和信号の交流
成分で補正し、フォーカスゆらぎの少ない補正フォーカ
ス差信号を得ることができ、シーク時の外乱振幅を低減
させることのできる安価な光ピックアップ装置を提供す
ることを目的としている。According to a second aspect of the present invention, the light receiving element is divided into eight light receiving areas, and among the eight light receiving areas, the amount of light received in four zero-order light receiving areas mainly receiving zero-order light is determined by the position. In the relationship, a, b, c, and d are defined around one direction, and the light receiving amounts of the four primary light receiving regions that mainly receive the 0th-order light and ± 1st-order light are represented by e, f, g, h in the positional relationship. When
A focus difference signal is obtained by (e + g)-(f + h), and an AC component of a sum signal (a + b + c + d) of the sum of the respective light receiving amounts of the zero-order light receiving area is added to the focus difference signal to generate a corrected focus difference signal. With this, the focus difference signal having the fluctuation of the astigmatism method can be corrected with the AC component of the sum signal of the zero-order light receiving area that does not include the track pattern with a simple circuit configuration, and a corrected focus difference signal with less focus fluctuation can be obtained. It is an object of the present invention to provide an inexpensive optical pickup device capable of reducing the disturbance amplitude at the time of seeking.

【００１４】請求項３記載の発明は、受光素子を、該受
光素子上のトラックの像と平行に配置されたトラック方
向分割線と、該トラック方向分割線上の所定の１点で当
該トラック方向分割線と所定角度で交わる３本の分割線
と、で４つの０次受光領域と、４つの１次受光領域と、
の８つの受光領域に分割することにより、受光素子を簡
単な分割形状で８つの受光領域に分割して、フォーカス
ゆらぎの少ない補正フォーカス差信号を得ることがで
き、シーク時の外乱振幅を低減させることのできる安価
な光ピックアップ装置を提供することを目的としてい
る。According to a third aspect of the present invention, the light receiving element is divided by a track direction dividing line arranged in parallel with an image of a track on the light receiving element and a predetermined point on the track direction dividing line. Three zero-order light-receiving areas, four primary light-receiving areas, and three division lines intersecting the line at a predetermined angle;
By dividing the light-receiving element into eight light-receiving areas, a light-receiving element can be divided into eight light-receiving areas with a simple division shape, and a corrected focus difference signal with little focus fluctuation can be obtained, and the disturbance amplitude at the time of seek can be reduced. It is an object of the present invention to provide an inexpensive optical pickup device capable of performing such operations.

【００１５】請求項４記載の発明は、受光素子を、該受
光素子上のトラックの像と平行に配置されたトラック方
向分割線と、該トラック方向分割線上の所定の直交点で
該トラック方向分割線と直交する直交分割線と、該トラ
ック方向分割線上の直交点とは異なる他の所定の１点を
端点とした２本の分割線と、該トラック方向分割線上の
直交点を挟んで前記所定の１点と反対側の所定の１点を
端点とした２本の分割線と、で４つの０次受光領域と、
４つの１次受光領域と、の８つの受光領域に分割するこ
とにより、トラックパターンが受光素子上で重なり合う
場合にも、０次受光領域と１次受光領域とを適切に分割
することができ、フォーカスゆらぎの少ない補正フォー
カス差信号を得ることができ、シーク時の外乱振幅を低
減させることのできる安価な光ピックアップ装置を提供
することを目的としている。According to a fourth aspect of the present invention, the light receiving element is divided by a track direction dividing line arranged in parallel with an image of a track on the light receiving element and a predetermined orthogonal point on the track direction dividing line. An orthogonal dividing line orthogonal to the line, two dividing lines having another predetermined point different from the orthogonal point on the track direction dividing line as an end point, and the predetermined And four zero-order light-receiving areas with two division lines having a predetermined point on the opposite side to one point as an end point,
By dividing into eight light receiving areas of four primary light receiving areas, the zero order light receiving area and the primary light receiving area can be appropriately divided even when the track patterns overlap on the light receiving element, It is an object of the present invention to provide an inexpensive optical pickup device that can obtain a corrected focus difference signal with little focus fluctuation and can reduce disturbance amplitude during a seek.

【００１６】請求項５記載の発明は、受光素子の８つの
受光領域のうち、０次光を主に受光する０次受光領域の
受光量の和を２値化することにより、０次光を受光する
０次受光領域の受光量から再生信号を生成し、再生分解
能を向上させることのできる光ピックアップ装置を提供
することを目的としている。According to a fifth aspect of the present invention, out of the eight light receiving regions of the light receiving element, the zero order light is binarized by binarizing the sum of the received light amounts of the zero order light receiving regions that mainly receive the zero order light. It is an object of the present invention to provide an optical pickup device capable of generating a reproduction signal from the amount of light received in a zero-order light receiving region for receiving light and improving the reproduction resolution.

【００１７】請求項６記載の発明は、受光素子の８つの
受光領域のうち、０次光を主に受光する４つの０次受光
領域の受光量を、当該４つの受光領域の位置関係におい
て一方向回りにａ、ｂ、ｃ、ｄとしたとき、２つの受光
量の和（ａ＋ｃ）あるいは（ｂ＋ｄ）を２値化すること
により、非点収差法の設計に応じた再生信号成分の高い
２つの受光領域の受光量の和信号から再生信号を生成し
て、再生分解能を向上させることのできる光ピックアッ
プ装置を提供することを目的としている。According to a sixth aspect of the present invention, among the eight light receiving areas of the light receiving element, the amount of light received in the four zero order light receiving areas mainly receiving the zero order light is reduced by the positional relationship between the four light receiving areas. Assuming that a, b, c, and d around the direction, the sum (a + c) or (b + d) of the two received light amounts is binarized, so that a reproduced signal component having a high reproduction signal component according to the design of the astigmatism method is obtained. It is an object of the present invention to provide an optical pickup device that can generate a reproduction signal from a sum signal of the light reception amounts of two light receiving regions and improve the reproduction resolution.

【００１８】[0018]

【課題を解決するための手段】請求項１記載の発明の光
ピックアップ装置は、光源からの光をトラックを有する
情報記録媒体上に集光し、当該光情報記録媒体からの反
射光に光学系により前記トラックに対して略４５度方向
の非点収差を与えて、受光素子に集光照射する光ピック
アップ装置において、前記受光素子は、前記トラックか
らの前記反射光のうち、０次光を主に受光する位置に配
置された４つの０次受光領域と、０次光と＋１次光また
は０次光と−１次光を受光する位置に配置された４つの
１次受光領域と、の８つの受光領域を有し、前記０次受
光領域の受光量を当該４つの０次受光領域の位置関係に
おいて一方向回りにａ、ｂ、ｃ、ｄとし、前記１次受光
領域の受光量を当該４つの１次受光領域の位置関係にお
いて一方向回りにｅ、ｆ、ｇ、ｈとしたとき、（ａ＋ｅ
＋ｃ＋ｇ）−（ｆ＋ｂ＋ｄ＋ｈ）を演算してフォーカス
差信号を生成するフォーカス差信号演算手段と、（ａ＋
ｂ＋ｃ＋ｄ）を演算する和信号演算手段と、前記和信号
演算手段の演算した和信号の交流成分を取り出す交流成
分取出手段と、前記フォーカス差信号演算手段の演算し
たフォーカス差信号と前記交流成分取出手段の取り出し
た前記和信号の交流成分を加算して補正フォーカス差信
号を生成する加算手段と、を備えることにより、上記目
的を達成している。According to the first aspect of the present invention, there is provided an optical pickup device which focuses light from a light source on an information recording medium having tracks and converts the light reflected from the optical information recording medium into an optical system. In the optical pickup device which gives astigmatism in the direction of about 45 degrees to the track and converges and irradiates the light receiving element, the light receiving element mainly emits the 0th order light among the reflected light from the track. And eight primary light-receiving regions arranged at positions for receiving zero-order light and + 1st-order light or zero-order light and -1st-order light. The light receiving amount of the primary light receiving region is defined as a, b, c, and d around one direction in the positional relationship of the four zero order light receiving regions. Around one direction in the positional relationship of the four primary light receiving areas , When f, g, and h, (a + e
+ C + g)-(f + b + d + h) to generate a focus difference signal, and (a +
b + c + d), an AC component extracting means for extracting an AC component of the sum signal calculated by the sum signal calculating means, a focus difference signal calculated by the focus difference signal calculating means, and the AC component extracting means. The above object is attained by providing an addition means for adding the AC component of the sum signal extracted above to generate a corrected focus difference signal.

【００１９】上記構成によれば、受光素子を８つの受光
領域に分割し、当該８つの受光領域のうち、０次光を主
に受光する４つの０次受光領域の受光量をその位置関係
において一方向回りにａ、ｂ、ｃ、ｄとし、０次光と±
１次光を主に受光する４つの１次受光領域の受光量をそ
の位置関係においてｅ、ｆ、ｇ、ｈとしたとき、（ａ＋
ｅ＋ｃ＋ｇ）−（ｆ＋ｂ＋ｄ＋ｈ）によりフォーカス差
信号を求め、このフォーカス差信号に０次受光領域の各
受光量の和（ａ＋ｂ＋ｃ＋ｄ）の和信号の交流成分を加
算して補正フォーカス差信号を生成しているので、非点
収差法の揺らぎのあるフォーカス差信号をトラックパタ
ーンを含まない０次受光領域の和信号の交流成分で補正
することができ、フォーカスゆらぎの少ない補正フォー
カス差信号を得ることができる。その結果、シーク時の
外乱振幅を低減させることができる。According to the above configuration, the light receiving element is divided into eight light receiving areas, and the light receiving amounts of the four zero-order light receiving areas mainly receiving the zero-order light among the eight light receiving areas are represented by the positional relationship. A, b, c, d around one direction, ± 0th order light ±
Assuming that the light receiving amounts of the four primary light receiving regions mainly receiving the primary light are e, f, g, and h in the positional relationship, (a +
The focus difference signal is obtained by e + c + g)-(f + b + d + h), and the corrected focus difference signal is generated by adding the AC component of the sum signal (a + b + c + d) of the respective light receiving amounts of the zero-order light receiving area to the focus difference signal. Therefore, the focus difference signal having the fluctuation of the astigmatism method can be corrected by the AC component of the sum signal of the zero-order light receiving area not including the track pattern, and a corrected focus difference signal having a small focus fluctuation can be obtained. As a result, the disturbance amplitude during the seek can be reduced.

【００２０】請求項２記載の発明の光ピックアップ装置
は、光源からの光をトラックを有する情報記録媒体上に
集光し、当該光情報記録媒体からの反射光に光学系によ
り前記トラックに対して略４５度方向の非点収差を与え
て、受光素子に集光照射する光ピックアップ装置におい
て、前記受光素子は、前記トラックからの前記反射光の
うち、０次光を主に受光する位置に配置された４つの０
次受光領域と、０次光と＋１次光または０次光と−１次
光を受光する位置に配置された４つの１次受光領域と、
の８つの受光領域を有し、前記０次受光領域の受光量を
当該４つの０次受光領域の位置関係において一方向回り
にａ、ｂ、ｃ、ｄとし、前記１次受光領域の受光量を当
該４つの１次受光領域の位置関係において一方向回りに
ｅ、ｆ、ｇ、ｈとしたとき、（ｅ＋ｇ）−（ｆ＋ｈ）を
演算してフォーカス差信号を生成するフォーカス差信号
演算手段と、（ａ＋ｂ＋ｃ＋ｄ）を演算する和信号演算
手段と、前記和信号演算手段の演算した和信号のの交流
成分を取り出す交流成分取出手段と、前記フォーカス差
信号演算手段の演算したフォーカス差信号と前記交流成
分取出手段の取り出した前記和信号の交流成分を加算し
て補正フォーカス差信号を生成する加算手段と、を備え
ることにより、上記目的を達成している。According to a second aspect of the present invention, in the optical pickup device, light from a light source is focused on an information recording medium having a track, and reflected light from the optical information recording medium is applied to the track by an optical system. In an optical pickup device that gives astigmatism in a direction of approximately 45 degrees and converges and irradiates a light receiving element, the light receiving element is disposed at a position that mainly receives a zero-order light among the reflected light from the track. Four zeros
A first light receiving region, and four primary light receiving regions arranged at positions for receiving the 0th light and the + 1st light or the 0th light and the -1st light,
And the amount of light received in the zero-order light receiving region is a, b, c, and d around one direction in the positional relationship of the four zero-order light receiving regions, and the amount of light received in the primary light receiving region Where (e + g)-(f + h) is calculated as e, f, g, and h in one direction around the positional relationship of the four primary light receiving regions, and a focus difference signal calculating means for calculating a focus difference signal. , (A + b + c + d), an AC component extracting means for extracting an AC component of the sum signal calculated by the sum signal calculating means, and a focus difference signal calculated by the focus difference signal calculating means and the AC signal. The above object is attained by providing an adding means for adding the AC component of the sum signal extracted by the component extracting means to generate a corrected focus difference signal.

【００２１】上記構成によれば、受光素子を８つの受光
領域に分割し、当該８つの受光領域のうち、０次光を主
に受光する４つの０次受光領域の受光量をその位置関係
において一方向回りにａ、ｂ、ｃ、ｄとし、０次光と±
１次光を主に受光する４つの１次受光領域の受光量をそ
の位置関係においてｅ、ｆ、ｇ、ｈとしたとき、（ｅ＋
ｇ）−（ｆ＋ｈ）によりフォーカス差信号を求め、この
フォーカス差信号に０次受光領域の各受光量の和（ａ＋
ｂ＋ｃ＋ｄ）の和信号の交流成分を加算して補正フォー
カス差信号を生成しているので、簡単な回路構成で非点
収差法の揺らぎのあるフォーカス差信号をトラックパタ
ーンを含まない０次受光領域の和信号の交流成分で補正
することができ、フォーカスゆらぎの少ない補正フォー
カス差信号を得ることができる。その結果、簡単な構成
で、かつ、安価にシーク時の外乱振幅を低減させること
ができる。According to the above configuration, the light receiving element is divided into eight light receiving areas, and the light receiving amounts of the four zero-order light receiving areas mainly receiving the zero-order light among the eight light receiving areas are represented by the positional relationship. A, b, c, d around one direction, ± 0th order light ±
When the light receiving amounts of the four primary light receiving areas mainly receiving the primary light are e, f, g, and h in the positional relationship, (e +
g)-(f + h) to determine a focus difference signal, and add the sum (a +
b + c + d), the corrected focus difference signal is generated by adding the AC components of the sum signal, so that the focus difference signal having fluctuations of the astigmatism method can be converted into a zero-order light receiving area not including a track pattern by a simple circuit configuration. Correction can be performed using the AC component of the sum signal, and a corrected focus difference signal with less focus fluctuation can be obtained. As a result, the disturbance amplitude during the seek can be reduced with a simple configuration and at a low cost.

【００２２】上記各場合において、例えば、請求項３に
記載するように、前記受光素子は、該受光素子上の前記
トラックの像と平行に配置されたトラック方向分割線
と、該トラック方向分割線上の所定の１点で当該トラッ
ク方向分割線と所定角度で交わる３本の分割線と、によ
り、前記トラックからの前記反射光のうち、前記０次光
を主に受光する位置に配置された前記４つの０次受光領
域と、前記０次光と前記＋１次光または前記０次光と前
記−１次光を受光する位置に配置された前記４つの１次
受光領域と、の８つの受光領域に分割されていてもよ
い。In each of the above cases, for example, as set forth in claim 3, the light receiving element includes a track direction dividing line arranged in parallel with the track image on the light receiving element, and The three division lines intersecting the track direction division line at a predetermined angle at a predetermined point, and the reflected light from the track is disposed at a position mainly receiving the zero-order light. Eight light receiving areas of four 0-order light receiving areas and the four primary light-receiving areas arranged at positions for receiving the 0-order light and the + 1-order light or the 0-order light and the -1st-order light May be divided.

【００２３】上記構成によれば、受光素子を、該受光素
子上のトラックの像と平行に配置されたトラック方向分
割線と、該トラック方向分割線上の所定の１点で当該ト
ラック方向分割線と所定角度で交わる３本の分割線と、
で４つの０次受光領域と、４つの１次受光領域と、の８
つの受光領域に分割しているので、受光素子を簡単な分
割形状で８つの受光領域に分割して、フォーカスゆらぎ
の少ない補正フォーカス差信号を得ることができ、簡単
な構成で、かつ、安価な受光素子によりシーク時の外乱
振幅を低減させることができる。According to the above construction, the light receiving element is divided into a track direction dividing line arranged in parallel with the track image on the light receiving element, and the track direction dividing line at a predetermined point on the track direction dividing line. Three dividing lines intersecting at a predetermined angle,
8 of the four zero-order light-receiving regions and the four primary light-receiving regions
Since the light receiving element is divided into eight light receiving areas, the light receiving element can be divided into eight light receiving areas with a simple division shape to obtain a corrected focus difference signal with little focus fluctuation, and a simple configuration and inexpensive The light receiving element can reduce the disturbance amplitude during the seek.

【００２４】また、例えば、請求項４に記載するよう
に、前記受光素子は、該受光素子上の前記トラックの像
と平行に配置されたトラック方向分割線と、該トラック
方向分割線上の所定の直交点で該トラック方向分割線と
直交する直交分割線と、該トラック方向分割線上の前記
直交点とは異なる他の所定の１点を端点とした２本の分
割線と、該トラック方向分割線上の前記直交点を挟んで
前記所定の１点と反対側の所定の１点を端点とした２本
の分割線と、により、前記トラックからの前記反射光の
うち、前記０次光を主に受光する位置に配置された前記
４つの０次受光領域と、前記０次光と前記＋１次光また
は前記０次光と前記−１次光を受光する位置に配置され
た前記４つの１次受光領域と、の８つの受光領域に分割
されていてもよい。Further, for example, as set forth in claim 4, the light receiving element includes a track direction dividing line arranged in parallel with the image of the track on the light receiving element, and a predetermined direction on the track direction dividing line. An orthogonal division line orthogonal to the track direction division line at an orthogonal point; two division lines having another predetermined point different from the orthogonal point on the track direction division line as an end point; Of the reflected light from the track, mainly by the 0th-order light, by two divided lines having a predetermined point opposite to the predetermined point on the opposite side of the orthogonal point as an end point. The four zero-order light receiving regions arranged at positions for receiving light, and the four primary light receiving regions arranged at positions for receiving the zero-order light and the + 1-order light or the zero-order light and the -1st-order light Area may be divided into eight light receiving areas.

【００２５】上記構成によれば、受光素子を、該受光素
子上のトラックの像と平行に配置されたトラック方向分
割線と、該トラック方向分割線上の所定の直交点で該ト
ラック方向分割線と直交する直交分割線と、該トラック
方向分割線上の直交点とは異なる他の所定の１点を端点
とした２本の分割線と、該トラック方向分割線上の直交
点を挟んで前記所定の１点と反対側の所定の１点を端点
とした２本の分割線と、で４つの０次受光領域と、４つ
の１次受光領域と、の８つの受光領域に分割しているの
で、トラックパターンが受光素子上で重なり合う場合に
も、０次受光領域と１次受光領域とを適切に分割して、
フォーカスゆらぎの少ない補正フォーカス差信号を得る
ことができ、安価にシーク時の外乱振幅を低減させるこ
とができる。According to the above construction, the light receiving element is divided into a track direction dividing line arranged in parallel with the track image on the light receiving element and the track direction dividing line at a predetermined orthogonal point on the track direction dividing line. An orthogonal dividing line that is orthogonal, two dividing lines having another predetermined point different from the orthogonal point on the track direction dividing line as an end point, and the predetermined one The track is divided into eight light receiving areas of four zero-order light receiving areas and four primary light receiving areas by two dividing lines having a predetermined point on the opposite side of the point as an end point. Even when the patterns overlap on the light receiving element, the zero-order light receiving region and the primary light receiving region are appropriately divided,
A corrected focus difference signal with less focus fluctuation can be obtained, and the disturbance amplitude during seek can be reduced at low cost.

【００２６】さらに、例えば、請求項５に記載するよう
に、前記光ピックアップ装置は、前記和信号演算手段の
演算結果を２値化する２値化手段、をさらに備えていて
もよい。Further, for example, as set forth in claim 5, the optical pickup device may further include a binarizing means for binarizing the operation result of the sum signal operation means.

【００２７】上記構成によれば、受光素子の８つの受光
領域のうち、０次光を主に受光する０次受光領域の受光
量の和を２値化しているので、フォーカスゆらぎの少な
い補正フォーカス差信号を得ることができ、安価にシー
ク時の外乱振幅を低減させることができるとともに、０
次光を受光する０次受光領域の受光量から再生信号を生
成することができ、再生分解能を向上させることができ
る。According to the above configuration, the sum of the light receiving amounts of the zero-order light receiving region that mainly receives the zero-order light among the eight light receiving regions of the light receiving element is binarized. The difference signal can be obtained, the disturbance amplitude at the time of seek can be reduced at low cost, and 0
A reproduction signal can be generated from the amount of light received in the 0th-order light receiving region for receiving the next light, and the reproduction resolution can be improved.

【００２８】また、例えば、請求項６に記載するよう
に、前記光ピックアップ装置は、（ａ＋ｃ）あるいは
（ｂ＋ｄ）を演算する和信号演算手段と、前記和信号演
算手段の演算した（ａ＋ｃ）あるいは（ｂ＋ｄ）の演算
結果を２値化する２値化手段と、をさらに備えていても
よい。Further, for example, as described in claim 6, the optical pickup device comprises a sum signal calculating means for calculating (a + c) or (b + d), and (a + c) or (a + c) calculated by the sum signal calculating means. A binarizing means for binarizing the result of the operation (b + d).

【００２９】上記構成によれば、受光素子の８つの受光
領域のうち、０次光を主に受光する４つの０次受光領域
の受光量を、当該４つの受光領域の位置関係において一
方向回りにａ、ｂ、ｃ、ｄとしたとき、２つの受光量の
和（ａ＋ｃ）あるいは（ｂ＋ｄ）を２値化しているの
で、フォーカスゆらぎの少ない補正フォーカス差信号を
得ることができ、安価にシーク時の外乱振幅を低減させ
ることができるとともに、非点収差法の設計に応じた再
生信号成分の高い２つの受光領域の受光量の和信号から
再生信号を生成することができ、再生分解能を向上させ
ることができる。According to the above configuration, of the eight light receiving areas of the light receiving element, the light receiving amounts of the four zero-order light receiving areas mainly receiving the zero-order light are changed in one direction in the positional relationship between the four light receiving areas. Since the sum (a + c) or (b + d) of the two received light amounts is binarized when a, b, c, and d are used, a corrected focus difference signal with little focus fluctuation can be obtained, and seek can be performed at low cost. In addition to reducing the disturbance amplitude at the time, the reproduction signal can be generated from the sum signal of the light receiving amounts of the two light receiving areas with high reproduction signal components according to the design of the astigmatism method, and the reproduction resolution is improved. Can be done.

【００３０】[0030]

【発明の実施の形態】以下、本発明の好適な実施の形態
を添付図面に基づいて詳細に説明する。なお、以下に述
べる実施の形態は、本発明の好適な実施の形態であるか
ら、技術的に好ましい種々の限定が付されているが、本
発明の範囲は、以下の説明において特に本発明を限定す
る旨の記載がない限り、これらの態様に限られるもので
はない。Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. It should be noted that the embodiments described below are preferred embodiments of the present invention, and therefore, various technically preferable limitations are added. However, the scope of the present invention is not limited to the following description. The embodiments are not limited to these embodiments unless otherwise specified.

【００３１】図１〜図８は、本発明の光ピックアップ装
置の第１の実施の形態を示す図であり、本実施の形態
は、請求項１及び請求項３に対応するものである。FIGS. 1 to 8 are views showing a first embodiment of the optical pickup device of the present invention, and this embodiment corresponds to claims 1 and 3. FIG.

【００３２】図１は、本発明の光ピックアップ装置の第
１の実施の形態を適用した光ピックアップ装置１０の要
部ブロック構成図であり、図１において、光ピックアッ
プ装置１０は、受光素子１１、演算回路１２、１３、Ａ
Ｃ結合回路１４、定数倍回路１５及び加算回路１６等を
備えている。FIG. 1 is a block diagram of a main part of an optical pickup device 10 to which the first embodiment of the optical pickup device according to the present invention is applied. In FIG. Arithmetic circuits 12, 13, A
It includes a C coupling circuit 14, a constant multiplication circuit 15, an addition circuit 16, and the like.

【００３３】受光素子１１は、図２に示すように、略四
角形に形成されており、その２辺が図３に示す光情報記
録媒体３０のトラック（案内溝）３１に平行な方向（タ
ンジェンシャル方向）に対して平行に配設されている。
受光素子１１は、１点Ｐで交差する４本の分割線１７、
１８、１９、２０により８つの受光領域１１Ａ、１１
Ｂ、１１Ｃ、１１Ｄ、１１Ｅ、１１Ｆ、１１Ｇ、１１Ｈ
に分割されている。すなわち、受光素子１１は、まず、
タンジェンシャル方向に平行な分割線（トラック方向分
割線）１７とトラック方向分割線１７の中央の１点Ｐで
直交しトラック３１と直交する方向（ラジアル方向）に
延在するラジアル方向分割線１８により４等分され、こ
の１点Ｐで交差し、略四角形の受光素子１１の対角線方
向に延在する分割線１９、２０により、さらに分割され
て８分割されている。As shown in FIG. 2, the light receiving element 11 is formed in a substantially rectangular shape, and two sides thereof are parallel to a track (guide groove) 31 of the optical information recording medium 30 shown in FIG. Direction).
The light receiving element 11 has four division lines 17 intersecting at one point P,
Eight light receiving areas 11A, 11 based on 18, 19, 20
B, 11C, 11D, 11E, 11F, 11G, 11H
Is divided into That is, the light receiving element 11 first
A dividing line (track direction dividing line) 17 parallel to the tangential direction and a radial direction dividing line 18 extending in a direction (radial direction) perpendicular to the track 31 at a point P at the center of the track direction dividing line 17. The light receiving element 11 is divided into four equal parts, intersected at this point P, and further divided into eight parts by dividing lines 19 and 20 extending in the diagonal direction of the substantially square light receiving element 11.

【００３４】いま、受光素子１１の上記８分割されたタ
ンジェンシャル方向（図２中上下方向）の４つの受光領
域を０次受光領域１１Ａ、１１Ｂ、１１Ｃ、１１Ｄと
し、残りの４つの受光領域を、１次受光領域１１Ｅ、１
１Ｆ、１１Ｇ、１１Ｈとすると、０次受光領域１１Ａ、
１１Ｂ、１１Ｃ、１１Ｄには、光情報記録媒体３０のト
ラック３１により回折された反射光が、非点収差を与え
る光学系（光学手段）を介して、図３に示すように、受
光素子１１に収束スポット２１として入射され、この収
束スポット２１のうち、光情報記録媒体３０のトラック
３１で反射された反射光は、トラックパターン２１ｉ、
２１ｊとして、主に１次受光領域１１Ｅ、１１Ｆと１次
受光領域１１Ｇ、１１Ｈに入射される。Now, the four light receiving areas of the light receiving element 11 in the tangential direction (vertical direction in FIG. 2) divided into eight are defined as zero-order light receiving areas 11A, 11B, 11C and 11D, and the remaining four light receiving areas are defined as , Primary light receiving area 11E, 1
1F, 11G, and 11H, the zero-order light receiving area 11A,
3B, the reflected light diffracted by the track 31 of the optical information recording medium 30 is transmitted to the light receiving element 11 via an optical system (optical means) for providing astigmatism, as shown in FIG. The incident light as a convergent spot 21, and among the convergent spot 21, the reflected light reflected on the track 31 of the optical information recording medium 30 is a track pattern 21 i,
As 21j, the light mainly enters the primary light receiving regions 11E and 11F and the primary light receiving regions 11G and 11H.

【００３５】すなわち、光ピックアップ装置１０におい
ては、図３に示したように、対物レンズ３２を介して光
スポット３３が光情報記録媒体３０のトラック面（記録
面）に集光照射され、該光スポット３３が光情報記録媒
体３０に形成されたトラック３１によって回折されて、
反射光として対物レンズ３２及び図示しない光学系を介
して受光素子１１に照射される。この光スポット３３の
反射光は、０次回折光（０次光）３４、＋１次回折光
（＋１次光）３５、−１次回折光（−１次光）３６、図
示しない±２次回折光、±３次回折光、・・・に分か
れ、この反射光が受光素子１１に集光照射される。した
がって、受光素子１１には、図４にも示したように、こ
れらの０次光３４、＋１次光３５及び−１次光３６の反
射光の収束スポット２１が照射され、収束スポット２１
は、０次光３４のみのスポット領域２０ｋと、０次光３
４と±１次光３５、３６の干渉しあう領域である上記ト
ラックパターン２１ｉ、２１ｊとから形成されることと
なる。That is, in the optical pickup device 10, as shown in FIG. 3, a light spot 33 is condensed and irradiated on a track surface (recording surface) of the optical information recording medium 30 via an objective lens 32, and The spot 33 is diffracted by the track 31 formed on the optical information recording medium 30,
The reflected light is emitted to the light receiving element 11 via the objective lens 32 and an optical system (not shown). The reflected light of the light spot 33 includes a 0th-order diffracted light (0th-order light) 34, a + 1st-order diffracted light (+ 1st-order light) 35, a -1st-order diffracted light (-1st-order light) 36, ± 2nd-order diffracted light (not shown), ± 3rd-order The reflected light is condensed and irradiated on the light receiving element 11. Therefore, the light receiving element 11 is irradiated with the convergent spot 21 of the reflected light of the 0-order light 34, the + 1st-order light 35, and the -1st-order light 36 as shown in FIG.
Is a spot area 20k including only the zero-order light 34 and a zero-order light 3
4 and the track patterns 21i and 21j, which are areas where the ± 1st-order lights 35 and 36 interfere with each other.

【００３６】また、図３において、直線３７がトラック
３１の像となっており、直線３７と平行な方向がトラッ
ク３１の方向である。そして、受光素子１１は、この直
線３７と平行な方向のトラック方向分割線１７、トラッ
ク方向分割線１７に直交するラジアル方向分割線１８及
び点Ｐで交差する分割線１９、２０により、８分割され
て、８つの受光領域１１Ａ〜１１Ｈが形成されている。In FIG. 3, a straight line 37 is an image of the track 31, and a direction parallel to the straight line 37 is the direction of the track 31. The light receiving element 11 is divided into eight parts by a track direction dividing line 17 in a direction parallel to the straight line 37, a radial direction dividing line 18 orthogonal to the track direction dividing line 17, and dividing lines 19 and 20 intersecting at a point P. Thus, eight light receiving regions 11A to 11H are formed.

【００３７】この８つの受光領域１１Ａ〜１１Ｈのう
ち、トラック方向分割線１７に隣接する４つの０次受光
領域１１Ａ〜１１Ｄには、反射光の０次光３４が入射さ
れ、ラジアル方向分割線１８に隣接する４つの１次受光
領域１１Ｅ〜１１Ｈには、反射光の０次光３４と±１次
光３５、３６が入射されることとなる。Of the eight light receiving areas 11A to 11H, the zero order light 34 of the reflected light enters the four zero order light receiving areas 11A to 11D adjacent to the track direction dividing line 17, and the radial direction dividing line 18 The 0th-order light 34 and the ± first-order lights 35 and 36 of the reflected light are incident on the four primary light receiving regions 11E to 11H adjacent to.

【００３８】再び、図１において、受光素子１１は、０
次光３４を主に受光する０次受光領域１１Ａ、１１Ｂ、
１１Ｃ、１１Ｄの出力ａ、ｂ、ｃ、ｄを演算回路１２及
び演算回路１３に出力するとともに、０次光３４と±１
次光３５、３６を主に受光する１次受光領域１１Ｅ、１
１Ｆ、１１Ｇ、１１Ｈの出力ｅ、ｆ、ｇ、ｈを演算回路
１２に出力する。Again, in FIG. 1, the light receiving element 11
0th order light receiving regions 11A, 11B mainly receiving the next light 34,
The outputs a, b, c, and d of 11C and 11D are output to the arithmetic circuit 12 and the arithmetic circuit 13, and the zero-order light 34 and ± 1
Primary light receiving areas 11E, 1 mainly receiving the next light 35, 36
The outputs e, f, g, and h of 1F, 11G, and 11H are output to the arithmetic circuit 12.

【００３９】演算回路（フォーカス差信号演算手段）１
２は、０次受光領域１１Ａの出力ａ、０次受光領域１１
Ｃの出力ｃ、１次受光領域１１Ｅの出力ｅ及び１次受光
領域１１Ｇの出力ｇの和から１次受光領域Ｆの出力ｆ、
０次受光領域１１Ｂの出力ｂ、０次受光領域１１Ｄの出
力ｄ及び１次受光領域Ｈの出力ｈの和を減算［（ａ＋ｅ
＋ｃ＋ｇ）−（ｆ＋ｂ＋ｄ＋ｈ）］して、加算回路１６
に出力する。すなわち、演算回路１２は、受光素子１１
を８分割した受光領域１１Ａ、１１Ｂ、１１Ｃ、１１
Ｄ、１１Ｅ、１１Ｆ、１１Ｇ、１１Ｈのうち、対角線方
向の受光領域１１Ａ、１１Ｅ、１１Ｃ、１１Ｇの各出力
ａ、ｅ、ｃ、ｇの和からこの対角方向と略直交する対角
方向に配置された受光領域１１Ｆ、１１Ｂ、１１Ｄ、１
１Ｈの出力ｆ、ｂ、ｄ、ｈの和を減算しているので、フ
ォーカス差信号［（ａ＋ｅ＋ｃ＋ｇ）−（ｆ＋ｂ＋ｄ＋
ｈ）］を算出していることとなる。Calculation circuit (focus difference signal calculation means) 1
2 is the output a of the zero-order light receiving area 11A,
The output f of the primary light receiving area F is obtained from the sum of the output c of the C, the output e of the primary light receiving area 11E, and the output g of the primary light receiving area 11G,
Subtract the sum of the output b of the zero-order light receiving region 11B, the output d of the zero-order light receiving region 11D, and the output h of the primary light receiving region H [(a + e
+ C + g)-(f + b + d + h)]
Output to That is, the arithmetic circuit 12 includes the light receiving element 11
Area 11A, 11B, 11C, 11
D, 11E, 11F, 11G, and 11H are arranged in a diagonal direction substantially orthogonal to the diagonal direction based on the sum of the outputs a, e, c, and g of the diagonal light receiving regions 11A, 11E, 11C, and 11G. Light receiving areas 11F, 11B, 11D, 1
Since the sum of the outputs f, b, d, and h of 1H is subtracted, the focus difference signal [(a + e + c + g)-(f + b + d +
h)] has been calculated.

【００４０】演算回路（和信号演算手段）１３は、０次
受光領域１１Ａ、１１Ｂ、１１Ｃ、１１Ｄの各出力ａ、
出力ｂ、出力ｃ、出力ｄの和（ａ＋ｂ＋ｃ＋ｄ）を演算
して、和信号（ａ＋ｂ＋ｃ＋ｄ）をＡＣ結合回路１４に
出力する。この演算回路１３の演算した和信号（ａ＋ｂ
＋ｃ＋ｄ）は、上述のように、主に０次光３４のみから
なる出力の和であるので、光情報記録媒体３０のピット
による回折信号成分を多く含んだ信号である。The operation circuit (sum signal operation means) 13 outputs the respective outputs a, 0, of the zero-order light receiving areas 11A, 11B, 11C, 11D.
The sum (a + b + c + d) of the outputs b, c, and d is calculated, and the sum signal (a + b + c + d) is output to the AC coupling circuit 14. The sum signal (a + b) calculated by the arithmetic circuit 13
As described above, + c + d) is the sum of outputs mainly composed of only the zero-order light 34, and is a signal that includes many diffraction signal components due to pits of the optical information recording medium 30.

【００４１】ＡＣ結合回路（交流成分取出手段）１４
は、演算回路１３の算出した和信号（ａ＋ｂ＋ｃ＋ｄ）
の交流成分を取り出して、定数倍回路１５に出力する。
定数倍回路１５は、ＡＣ結合回路１４の取り出した和信
号（ａ＋ｂ＋ｃ＋ｄ）の交流成分を定数倍して加算回路
１６に出力する。AC coupling circuit (AC component extracting means) 14
Is the sum signal (a + b + c + d) calculated by the arithmetic circuit 13
And outputs it to the constant multiplication circuit 15.
The constant multiplication circuit 15 multiplies the AC component of the sum signal (a + b + c + d) extracted by the AC coupling circuit 14 by a constant and outputs the result to the addition circuit 16.

【００４２】加算回路（加算手段）１６には、上述のよ
うに、演算回路１２の演算したフォーカス差信号Ｆｏ
［（ａ＋ｅ＋ｃ＋ｇ）−（ｆ＋ｂ＋ｄ＋ｈ）］と演算回
路１３が演算した和信号（ａ＋ｂ＋ｃ＋ｄ）の交流成分
をＡＣ結合回路１４で取り出して、定数倍回路１５で整
数倍した信号が入力されており、加算回路１６は、これ
らのフォーカス差信号［（ａ＋ｅ＋ｃ＋ｇ）−（ｆ＋ｂ
＋ｄ＋ｈ）］と和信号（ａ＋ｂ＋ｃ＋ｄ）の交流成分の
定数倍した信号を加算して、補正フォーカス差信号ＡＦ
ｏとして出力する。As described above, the adder circuit (adder means) 16 supplies the focus difference signal Fo calculated by the arithmetic circuit 12 as described above.
The AC component of the sum signal (a + b + c + d) calculated by the arithmetic circuit 13 and [(a + e + c + g)-(f + b + d + h)] is extracted by the AC coupling circuit 14, and a signal multiplied by an integer by the constant multiplication circuit 15 is input. 16 is the focus difference signal [(a + e + c + g)-(f + b
+ D + h)] and a signal obtained by multiplying the AC signal of the sum signal (a + b + c + d) by a constant, and adding the corrected focus difference signal AF
Output as o.

【００４３】次に、本実施の形態の作用を説明する。光
ピックアップ装置１０は、受光素子１１が、図２に示し
たように、タンジェンシャル方向に平行なトラック方向
分割線１７とタンジェンシャル方向に直交する方向のラ
ジアル方向分割線１８により、４分割され、略四角形の
受光素子１１の対角線方向の分割線１９、２０により、
さらに分割されて、全体として８分割されている。受光
素子１１の８分割された受光領域１１Ａ〜１１Ｈのう
ち、タンジェンシャル方向の４つの０次受光領域１１
Ａ、１１Ｂ、１１Ｃ、１１Ｄには、光情報記録媒体３０
のトラック３１により回折された反射光が、図３及び図
４に示したように、収束スポット２１として入射され、
この収束スポット２１のうち、光情報記録媒体３０のト
ラック３１で反射された反射光は、トラックパターン２
１ｉ、２１ｊとして、主に１次受光領域１１Ｅ、１１
Ｆ、１１Ｇ、１１Ｈに入射される。Next, the operation of the present embodiment will be described. In the optical pickup device 10, the light receiving element 11 is divided into four by a track direction dividing line 17 parallel to the tangential direction and a radial direction dividing line 18 perpendicular to the tangential direction, as shown in FIG. By the dividing lines 19 and 20 in the diagonal direction of the light receiving element 11 having a substantially square shape,
It is further divided into eight parts as a whole. Of the eight divided light receiving areas 11A to 11H of the light receiving element 11, four zero-order light receiving areas 11 in the tangential direction
A, 11B, 11C, and 11D include an optical information recording medium 30.
The reflected light diffracted by the track 31 is incident as a convergent spot 21 as shown in FIGS.
The reflected light of the convergent spot 21 reflected by the track 31 of the optical information recording medium 30 is the track pattern 2
1i and 21j, mainly the primary light receiving areas 11E and 11
F, 11G, and 11H.

【００４４】そして、演算回路１２は、受光素子１１の
各受光領域１１Ａ〜１１Ｈのうち、図１中右斜め上から
左斜め下方向の対角方向に配置された受光領域１１Ａ、
１１Ｅ、１１Ｃ、１１Ｇの各出力ａ、ｅ、ｃ、ｇの和
（ａ、ｅ、ｃ、ｇ）からこの対角方向と略直交する対角
方向に配置された受光領域１１Ｆ、１１Ｂ、１１Ｄ、１
１Ｈの出力ｆ、ｂ、ｄ、ｈの和（ｆ、ｂ、ｄ、ｈ）を減
算して、フォーカス差信号Ｆｏ［（ａ＋ｅ＋ｃ＋ｇ）−
（ｆ＋ｂ＋ｄ＋ｈ）］を加算回路１６に出力する。The arithmetic circuit 12 includes a light receiving area 11A, which is arranged diagonally from the upper right to the lower left in FIG. 1, among the light receiving areas 11A to 11H of the light receiving element 11.
From the sums (a, e, c, g) of the outputs a, e, c, g of 11E, 11C, 11G, light receiving areas 11F, 11B, 11D, arranged in a diagonal direction substantially orthogonal to the diagonal direction. 1
The sum (f, b, d, h) of the outputs f, b, d, and h of 1H is subtracted, and the focus difference signal Fo [(a + e + c + g) −
(F + b + d + h)] to the adder circuit 16.

【００４５】そして、演算回路１３は、０次光３４を主
に受光する０次受光領域１１Ａ、１１Ｂ、１１Ｃ、１１
Ｄの出力ａ、ｂ、ｃ、ｄの和を算出して、和信号（ａ＋
ｂ＋ｃ＋ｄ）をＡＣ結合回路１４に出力し、ＡＣ結合回
路１４は、和信号（ａ＋ｂ＋ｃ＋ｄ）の交流成分を取り
出して、定数倍回路１５に出力する。定数倍回路１５
は、ＡＣ結合回路１４の取り出した和信号（ａ＋ｂ＋ｃ
＋ｄ）の交流成分を定数倍して、加算回路１６に出力す
る。Then, the arithmetic circuit 13 outputs the zero-order light receiving areas 11A, 11B, 11C, 11 mainly receiving the zero-order light 34.
The sum of the outputs a, b, c, and d of D is calculated, and the sum signal (a +
b + c + d) is output to the AC coupling circuit 14. The AC coupling circuit 14 extracts the AC component of the sum signal (a + b + c + d) and outputs it to the constant multiplying circuit 15. Constant multiplication circuit 15
Is the sum signal (a + b + c) extracted by the AC coupling circuit 14.
+ D) is multiplied by a constant and output to the adder circuit 16.

【００４６】加算回路１６は、演算回路１２から入力さ
れるフォーカス差信号Ｆｏと定数倍回路１５から入力さ
れる和信号（ａ＋ｂ＋ｃ＋ｄ）の交流成分の定数倍を加
算して、補正フォーカス差信号ＡＦｏを出力する。The adding circuit 16 adds the focus difference signal Fo input from the arithmetic circuit 12 and a constant multiple of the AC component of the sum signal (a + b + c + d) input from the constant multiplying circuit 15 to generate a corrected focus difference signal AFo. Output.

【００４７】通常、光情報記録媒体に照射される光スポ
ットが光情報記録媒体の１本のトラックを垂直方向に横
切った場合、従来の４分割非点収差法でのフォーカス差
信号の変動状態は、図５のように示すことができる。す
なわち、図５において、横軸は、光スポットがトラック
の中心に対してどれだけ変位したかを示すオフトラッ
ク、縦軸は、その時のフォーカス差信号の変動（すなわ
ち、フォーカス揺らぎ）を相対値で示したものであり、
図５では、フォーカス揺らぎの様子を分かりやすくする
ために、光スポットを光情報記録媒体の記録面に対して
０．５μｍデフォーカスさせている。また、図５では、
トラックピッチを１．６μｍとしており、横軸の±０．
８μｍがトラック１本分に該当している。図５におい
て、□で示す線が、従来のフォーカス差信号（フォーカ
ス揺らぎ）であり、●で示す線が、０次光を主に受光す
る受光領域の出力の和信号（０次和光量）である。図５
から分かるように、フォーカス差信号と和信号とは、逆
相となっている。したがって、フォーカス差信号と和信
号とを加算することにより、フォーカス差信号の揺らぎ
をキャンセルすることができるが、和信号は、常に正の
値をとるため、単に加算しただけでは、その分だけオフ
セットが生じる。Normally, when the light spot irradiated on the optical information recording medium crosses one track of the optical information recording medium in the vertical direction, the change state of the focus difference signal in the conventional four-division astigmatism method is as follows. , FIG. That is, in FIG. 5, the horizontal axis represents the off-track indicating how much the light spot is displaced with respect to the center of the track, and the vertical axis represents the variation of the focus difference signal (ie, focus fluctuation) at that time as a relative value. It is shown,
In FIG. 5, the light spot is defocused by 0.5 μm with respect to the recording surface of the optical information recording medium in order to easily understand the state of the focus fluctuation. In FIG. 5,
The track pitch is set to 1.6 μm, and ± 0.
8 μm corresponds to one track. In FIG. 5, a line indicated by □ is a conventional focus difference signal (focus fluctuation), and a line indicated by ● is a sum signal (zero-order sum light amount) of the output of the light receiving region that mainly receives the zero-order light. is there. FIG.
As can be seen from FIG. 7, the focus difference signal and the sum signal have opposite phases. Therefore, the fluctuation of the focus difference signal can be canceled by adding the focus difference signal and the sum signal. However, the sum signal always takes a positive value. Occurs.

【００４８】そこで、本実施の形態においては、上述の
ように、和信号（ａ＋ｂ＋ｃ＋ｄ）の交流成分のみを取
り出すとともに、キャンセルを最適に行うために、交流
成分に適当な定数を乗じて（定数倍して）、フォーカス
差信号Ｆｏに加算している。すなわち、演算回路１２
は、受光素子１１を８分割した受光領域１１Ａ〜１１Ｈ
のうち、対角線方向の受光領域１１Ａ、１１Ｅ、１１
Ｃ、１１Ｇの各出力ａ、ｅ、ｃ、ｇの和（ａ、ｅ、ｃ、
ｇ）からこの対角方向と略直交する対角方向に配設され
た受光領域１１Ｆ、１１Ｂ、１１Ｄ、１１Ｈの出力ｆ、
ｂ、ｄ、ｈの和（ｆ、ｂ、ｄ、ｈ）を減算して、フォー
カス差信号Ｆｏ［（ａ＋ｅ＋ｃ＋ｇ）−（ｆ＋ｂ＋ｄ＋
ｈ）］を加算回路１６に出力し、演算回路１３は、０次
受光領域１１Ａ、１１Ｂ、１１Ｃ、１１Ｄの各出力ａ、
出力ｂ、出力ｃ、出力ｄの和（ａ＋ｂ＋ｃ＋ｄ）を演算
して、和信号（ａ＋ｂ＋ｃ＋ｄ）をＡＣ結合回路１４に
出力する。ＡＣ結合回路１４は、和信号（ａ＋ｂ＋ｃ＋
ｄ）から交流成分を取り出し、ＡＣ結合回路１４の取り
出した和信号の交流成分を定数倍回路１５で定数倍し
て、加算回路１６に出力する。加算回路１６が、フォー
カス差信号Ｆｏ［（ａ＋ｅ＋ｃ＋ｇ）−（ｆ＋ｂ＋ｄ＋
ｈ）］と和信号（ａ＋ｂ＋ｃ＋ｄ）の交流成分を定数倍
した信号を加算して、補正フォーカス差信号ＡＦｏとし
て出力する。Therefore, in the present embodiment, as described above, only the AC component of the sum signal (a + b + c + d) is extracted, and the AC component is multiplied by an appropriate constant (constant multiplication) in order to optimally perform cancellation. Then, it is added to the focus difference signal Fo. That is, the arithmetic circuit 12
Are light receiving areas 11A to 11H obtained by dividing the light receiving element 11 into eight parts.
Of the light receiving areas 11A, 11E, 11 in the diagonal direction
The sum of each output a, e, c, g of C, 11G (a, e, c,
g), the outputs f of the light receiving areas 11F, 11B, 11D, 11H arranged in a diagonal direction substantially orthogonal to this diagonal direction,
The sum (f, b, d, h) of b, d, h is subtracted, and the focus difference signal Fo [(a + e + c + g)-(f + b + d +
h)] to the adding circuit 16, and the arithmetic circuit 13 outputs the respective outputs a, 0, of the zero-order light receiving areas 11A, 11B, 11C, 11D.
The sum (a + b + c + d) of the outputs b, c, and d is calculated, and the sum signal (a + b + c + d) is output to the AC coupling circuit 14. The AC coupling circuit 14 outputs the sum signal (a + b + c +
The AC component is extracted from d), the AC component of the sum signal extracted by the AC coupling circuit 14 is multiplied by a constant in a constant multiplication circuit 15, and is output to an addition circuit 16. The adder circuit 16 outputs the focus difference signal Fo [(a + e + c + g)-(f + b + d +
h)] and a signal obtained by multiplying the AC component of the sum signal (a + b + c + d) by a constant, and output the corrected focus difference signal AFo.

【００４９】したがって、演算回路１２の算出したフォ
ーカス差信号Ｆｏに存在する揺らぎを和信号（ａ＋ｂ＋
ｃ＋ｄ）で補正することができるとともに、和信号（ａ
＋ｂ＋ｃ＋ｄ）の交流成分のみを加算しているので、オ
フセットを生じさせることなく、適切にフォーカス差信
号Ｆｏの揺らぎをキャンセルして、補正した補正フォー
カス差信号ＡＦｏを得ることができる。また、和信号
（ａ＋ｂ＋ｃ＋ｄ）の交流成分を定数倍してフォーカス
差信号Ｆｏに加算しているので、フォーカス差信号Ｆｏ
を適切にキャンセルして、フォーカス差信号Ｆｏの揺ら
ぎを補正して、補正フォーカス差信号ＡＦｏを得ること
ができる。Therefore, the fluctuation existing in the focus difference signal Fo calculated by the arithmetic circuit 12 is added to the sum signal (a + b +
c + d) and the sum signal (a
Since only the AC component of (+ b + c + d) is added, the fluctuation of the focus difference signal Fo can be appropriately canceled without causing an offset, and the corrected corrected focus difference signal AFo can be obtained. Also, since the AC component of the sum signal (a + b + c + d) is multiplied by a constant and added to the focus difference signal Fo, the focus difference signal Fo is
Can be appropriately canceled, and the fluctuation of the focus difference signal Fo can be corrected to obtain the corrected focus difference signal AFo.

【００５０】本実施の形態によるフォーカス差信号Ｆｏ
と補正後の補正フォーカス差信号ＡＦｏを、デフォーカ
スが、それぞれ０．５μｍ、１．０μｍ及び１．５μｍ
のときについて、調べたところ、図６から図８に示すよ
うな結果を得た。なお、図６から図８において、横軸
は、光スポットがトラックの中心に対してどれだけ変位
したかを示すオフトラック、縦軸は、その時のフォーカ
ス差信号であり、□で示す線が、演算回路１２の算出し
たフォーカス差信号（フォーカス揺らぎ）Ｆｏであり、
●で示す線が、補正後の補正フォーカス差信号ＡＦｏで
ある。The focus difference signal Fo according to the present embodiment
And the corrected focus difference signal AFo after the correction is defocused to 0.5 μm, 1.0 μm and 1.5 μm, respectively.
Investigation was performed for the case of, and the results as shown in FIGS. 6 to 8 were obtained. 6 to 8, the horizontal axis represents off-track indicating how much the light spot is displaced with respect to the center of the track, and the vertical axis represents a focus difference signal at that time. A focus difference signal (focus fluctuation) Fo calculated by the arithmetic circuit 12,
The line indicated by ● is the corrected focus difference signal AFo after the correction.

【００５１】すなわち、図６は、デフォーカスが０．５
μｍのときを、図７は、デフォーカスが１．０μｍのと
きを、そして、図８は、デフォーカスが１．５μｍのと
きを、それぞれ示しており、図６〜図８から分かるよう
に、補正フォーカス差信号ＡＦｏが、フォーカス差信号
Ｆｏに比較して、大幅に揺らぎが小さくなっている。ま
た、図６から図８において、デフォーカスが大きくなる
に従って、フォーカス差信号Ｆｏが大きくなっており、
補正した補正フォーカス差信号ＡＦｏが、フォーカス差
信号としての機能を果たし、補正フォーカス差信号ＡＦ
ｏがフォーカスＳ字形状をしている。That is, FIG. 6 shows that the defocus is 0.5
7 shows the case where the defocus is 1.0 μm, and FIG. 8 shows the case where the defocus is 1.5 μm. As can be seen from FIGS. The fluctuation of the corrected focus difference signal AFo is significantly smaller than that of the focus difference signal Fo. 6 to 8, the focus difference signal Fo increases as the defocus increases.
The corrected corrected focus difference signal AFo functions as a focus difference signal, and the corrected focus difference signal AFo
o has a focus S-shape.

【００５２】このように、本実施の形態によれば、受光
素子１１を８つの受光領域１１Ａ〜１１Ｈに分割し、当
該８つの受光領域１１Ａ〜１１Ｈのうち、０次光を主に
受光する４つの０次受光領域１１Ａ〜１１Ｄの受光量を
その位置関係において一方向回りにａ、ｂ、ｃ、ｄと
し、０次光と±１次光を主に受光する４つの１次受光領
域１１Ｅ〜１１Ｈの受光量をその位置関係においてｅ、
ｆ、ｇ、ｈとしたとき、演算回路１２で（ａ＋ｅ＋ｃ＋
ｇ）−（ｆ＋ｂ＋ｄ＋ｈ）を演算して、フォーカス差信
号Ｆｏを求め、このフォーカス差信号Ｆｏに、０次受光
領域１１Ａ〜１１Ｄの各受光量の和（ａ＋ｂ＋ｃ＋ｄ）
を演算回路１３で演算して、この和信号（ａ＋ｂ＋ｃ＋
ｄ）の交流成分をＡＣ結合回路１４で取り出して、定数
倍回路１５で定数倍して、加算回路１６で、加算して補
正フォーカス差信号ＡＦｏを生成しているので、非点収
差法の揺らぎのあるフォーカス差信号Ｆｏをトラックパ
ターンを含まない０次受光領域１１Ａ〜１１Ｄの和信号
（ａ＋ｂ＋ｃ＋ｄ）の交流成分で補正し、フォーカスゆ
らぎの少ない補正フォーカス差信号ＡＦｏを得ることが
でき、シーク時の外乱振幅を低減させることができる。As described above, according to the present embodiment, the light receiving element 11 is divided into eight light receiving areas 11A to 11H, and among the eight light receiving areas 11A to 11H, the light receiving element mainly receiving the 0th-order light. The light receiving amounts of the zero order light receiving regions 11A to 11D are a, b, c, and d around one direction in the positional relationship, and the four primary light receiving regions 11E to 11 mainly receive the zero order light and the ± first order light. The received light amount of 11H is represented by e,
Assuming that f, g, and h, (a + e + c +
g)-(f + b + d + h) is calculated to obtain a focus difference signal Fo, and the focus difference signal Fo is added to the sum (a + b + c + d) of the respective light receiving amounts of the zero-order light receiving areas 11A to 11D.
Is calculated by the arithmetic circuit 13, and the sum signal (a + b + c +
The AC component of d) is taken out by the AC coupling circuit 14, multiplied by a constant by the constant multiplication circuit 15, and added by the addition circuit 16 to generate the corrected focus difference signal AFo. Is corrected by the AC component of the sum signal (a + b + c + d) of the zero-order light receiving areas 11A to 11D not including the track pattern, and a corrected focus difference signal AFo with less focus fluctuation can be obtained. The disturbance amplitude can be reduced.

【００５３】また、和信号（ａ＋ｂ＋ｃ＋ｄ）の交流成
分を定数倍して、フォーカス差信号Ｆｏに加算している
ので、フォーカス差信号Ｆｏの揺らぎを適切にキャンセ
ルすることができる。Since the AC component of the sum signal (a + b + c + d) is multiplied by a constant and added to the focus difference signal Fo, the fluctuation of the focus difference signal Fo can be appropriately canceled.

【００５４】図９〜図１２は、本発明の光ピックアップ
装置の第２の実施の形態を示す図であり、本実施の形態
は、簡単な回路構成で、フォーカス差信号の揺らぎを補
正するもので、請求項２及び請求項３に対応するもので
ある。FIGS. 9 to 12 are views showing a second embodiment of the optical pickup device of the present invention. This embodiment is a device which corrects the fluctuation of the focus difference signal with a simple circuit configuration. This corresponds to claims 2 and 3.

【００５５】なお、本実施の形態は、上記第１の実施の
形態と同様の光ピックアップ装置に適用したものであ
り、本実施の形態の説明においては、第１の実施の形態
の光ピックアップ装置と同様の構成部分には、同一の符
号を付して、その詳細な説明を省略する。The present embodiment is applied to the same optical pickup device as that of the first embodiment. In the description of this embodiment, the optical pickup device of the first embodiment will be described. The same components as those described above are denoted by the same reference numerals, and detailed description thereof will be omitted.

【００５６】図９において、光ピックアップ装置４０
は、受光素子１１、演算回路４１、演算回路１３、ＡＣ
結合回路１４、定数倍回路１５及び加算回路１６等を備
えており、受光素子１１は、上記第１の実施の形態の受
光素子１１と同様のものである。In FIG. 9, the optical pickup device 40
Is a light receiving element 11, an arithmetic circuit 41, an arithmetic circuit 13, AC
The light receiving element 11 includes a coupling circuit 14, a constant multiplying circuit 15, an addition circuit 16, and the like. The light receiving element 11 is the same as the light receiving element 11 of the first embodiment.

【００５７】受光素子１１の０次受光領域１１Ａ〜１１
Ｄの出力ａ〜ｄが演算回路１３に入力され、受光素子１
１の１次受光領域１１Ｅ〜１１Ｈの出力ｅ〜ｈが演算回
路４１に入力されている。The zero-order light receiving areas 11A to 11 of the light receiving element 11
D outputs a to d are input to the arithmetic circuit 13 and the light receiving element 1
The outputs e to h of the first primary light receiving regions 11E to 11H are input to the arithmetic circuit 41.

【００５８】演算回路（フォーカス差信号演算手段）４
１は、受光素子１１の１次受光領域１１Ｅ〜１１Ｈの出
力ｅ〜ｈから（ｅ＋ｇ）−（ｆ＋ｈ）を演算して、フォ
ーカス差信号Ｆｏを加算回路１６に出力する。Calculation circuit (focus difference signal calculation means) 4
1 calculates (e + g)-(f + h) from the outputs e to h of the primary light receiving areas 11E to 11H of the light receiving element 11, and outputs the focus difference signal Fo to the addition circuit 16.

【００５９】演算回路１３は、第１の実施の形態と同様
に、受光素子１１の０次受光領域１１Ａ〜１１Ｄの出力
ａ〜ｄを加算して、和信号（ａ＋ｂ＋ｃ＋ｄ）を生成
し、和信号（ａ＋ｂ＋ｃ＋ｄ）をＡＣ結合回路１４に出
力する。As in the first embodiment, the arithmetic circuit 13 adds the outputs a to d of the zero-order light receiving areas 11A to 11D of the light receiving element 11 to generate a sum signal (a + b + c + d). (A + b + c + d) is output to the AC coupling circuit 14.

【００６０】ＡＣ結合回路１４及び定数倍回路１５は、
上記第１の実施の形態と同様であり、演算回路４１の算
出した和信号の交流成分を取り出し、定数倍して、加算
回路１６に出力する。The AC coupling circuit 14 and the constant multiplication circuit 15
As in the first embodiment, the AC component of the sum signal calculated by the arithmetic circuit 41 is extracted, multiplied by a constant, and output to the adding circuit 16.

【００６１】加算回路１６は、演算回路４１から入力さ
れるフォーカス差信号Ｆｏと定数倍回路１５から入力さ
れる和信号（ａ＋ｂ＋ｃ＋ｄ）の交流成分の定数倍を加
算して、補正フォーカス差信号ＡＦｏとして出力する。The adding circuit 16 adds a constant multiple of the AC component of the focus difference signal Fo input from the arithmetic circuit 41 and the sum signal (a + b + c + d) input from the constant multiplying circuit 15 to obtain a corrected focus difference signal AFo. Output.

【００６２】本実施の形態の光ピックアップ装置４０に
よるフォーカス差信号Ｆｏと補正フォーカス差信号ＡＦ
ｏを、デフォーカスが、それぞれ０．５μｍ、１．０μ
ｍ及び１．５μｍのときについて調べたところ、図１０
から図１２に示すような結果を得た。なお、図１０から
図１２において、横軸は、光スポットがトラックの中心
に対してどれだけ変位したかを示すオフトラック、縦軸
は、その時のフォーカス差信号であり、□で示す線が、
演算回路４１の算出したフォーカス差信号（フォーカス
揺らぎ）Ｆｏであり、●で示す線が、補正後の補正フォ
ーカス差信号ＡＦｏである。The focus difference signal Fo and the corrected focus difference signal AF by the optical pickup device 40 of the present embodiment.
o is 0.5 μm and 1.0 μm, respectively.
10 and 10 μm, FIG.
As a result, the result as shown in FIG. 12 was obtained. In FIGS. 10 to 12, the horizontal axis is off-track indicating how much the light spot is displaced from the center of the track, and the vertical axis is the focus difference signal at that time.
This is the focus difference signal (focus fluctuation) Fo calculated by the arithmetic circuit 41, and the line indicated by ● is the corrected focus difference signal AFo after correction.

【００６３】すなわち、図１０は、デフォーカスが０．
５μｍのときを、図１１は、デフォーカスが１．０μｍ
のときを、そして、図１２は、デフォーカスが１．５μ
ｍのときを、それぞれ示しており、補正フォーカス差信
号ＡＦｏが、フォーカス差信号Ｆｏに比較して、大幅に
揺らぎが小さくなっている。また、図１０から図１２に
おいて、上記第１の実施の形態の場合と同様に、デフォ
ーカスが大きくなるに従って、フォーカス差信号Ｆｏが
大きくなっており、補正した補正フォーカス差信号ＡＦ
ｏが、フォーカス差信号としての機能を果たし、補正フ
ォーカス差信号ＡＦｏがフォーカスＳ字形状をしてい
る。但し、フォーカス差信号Ｆｏと補正フォーカス差信
号ＡＦｏとを比較すると、補正フォーカス差信号ＡＦｏ
は、フォーカス差信号Ｆｏよりもその絶対値が小さくな
る、すなわち、フォーカス感度が落ちるが、揺らぎは小
さくなっていることが分かる。したがって、フォーカス
制御系にとっての揺らぎが、感度に反比例するため、第
１の実施の形態に比較して、感度が落ちる分だけ、フォ
ーカス制御系にとっての揺らぎ低減効果は低下するが、
演算回路４１が第１の実施の形態の演算回路１２に比較
して、大幅に簡素化されており、コストを低減させるこ
とができる。That is, FIG.
FIG. 11 shows that the defocus is 1.0 μm when the distance is 5 μm.
And FIG. 12 shows that the defocus is 1.5 μm.
m, respectively, and the fluctuation of the corrected focus difference signal AFo is significantly smaller than that of the focus difference signal Fo. In FIGS. 10 to 12, the focus difference signal Fo increases as the defocus increases, as in the case of the first embodiment.
o functions as a focus difference signal, and the corrected focus difference signal AFo has a focus S-shape. However, comparing the focus difference signal Fo with the corrected focus difference signal AFo, the corrected focus difference signal AFo
Is smaller than the focus difference signal Fo, that is, the focus sensitivity is lowered, but the fluctuation is smaller. Therefore, since the fluctuation for the focus control system is inversely proportional to the sensitivity, the fluctuation reduction effect for the focus control system is reduced as much as the sensitivity is reduced as compared with the first embodiment.
The operation circuit 41 is greatly simplified as compared with the operation circuit 12 of the first embodiment, and the cost can be reduced.

【００６４】したがって、本実施の形態によれば、受光
素子１１を８つの受光領域１１Ａ〜１１Ｈに分割し、当
該８つの受光領域１１Ａ〜１１Ｈのうち、０次光を主に
受光する４つの０次受光領域１１Ａ〜１１Ｄの受光量を
その位置関係において一方向回りにａ、ｂ、ｃ、ｄと
し、０次光と±１次光を主に受光する４つの１次受光領
域１１Ｅ〜１１Ｈの受光量をその位置関係においてｅ、
ｆ、ｇ、ｈとしたとき、演算回路１２で（ｅ＋ｇ）−
（ｆ＋ｈ）を演算して、フォーカス差信号Ｆｏを求め、
このフォーカス差信号Ｆｏに、０次受光領域１１Ａ〜１
１Ｄの各受光量の和（ａ＋ｂ＋ｃ＋ｄ）を演算回路１３
で演算して、この和信号（ａ＋ｂ＋ｃ＋ｄ）の交流成分
をＡＣ結合回路１４で取り出して、定数倍回路１５で定
数倍して、加算回路１６で、加算して補正フォーカス差
信号ＡＦｏを生成しているので、簡単で、安価な回路構
成により、非点収差法の揺らぐフォーカス差信号Ｆｏを
トラックパターンを含まない０次受光領域１１Ａ〜１１
Ｄの和信号の交流成分で補正し、フォーカスゆらぎの少
ない補正フォーカス差信号ＡＦｏを得ることができる。
その結果、シーク時の外乱振幅を低減させることのでき
る光ピックアップ装置４０を簡単な構成で、安価なもの
とすることができる。Therefore, according to the present embodiment, light receiving element 11 is divided into eight light receiving areas 11A to 11H, and four light receiving areas mainly receiving zero-order light among the eight light receiving areas 11A to 11H. The light receiving amounts of the next light receiving regions 11A to 11D are set to a, b, c, and d around one direction in the positional relationship, and four primary light receiving regions 11E to 11H mainly receiving the 0th order light and the ± 1st order light. The amount of received light is e,
Assuming that f, g, and h, the arithmetic circuit 12 calculates (e + g)-
(F + h) to obtain a focus difference signal Fo,
The zero-order light receiving areas 11A to 11A are added to the focus difference signal Fo.
The arithmetic circuit 13 calculates the sum (a + b + c + d) of the 1D received light amounts.
The AC component of the sum signal (a + b + c + d) is extracted by an AC coupling circuit 14, multiplied by a constant by a constant multiplication circuit 15, and added by an addition circuit 16 to generate a corrected focus difference signal AFo. Therefore, with a simple and inexpensive circuit configuration, the fluctuating focus difference signal Fo of the astigmatism method can be used to transmit the zero-order light receiving areas 11A to 11A including no track pattern.
The correction is performed using the AC component of the sum signal of D, and a corrected focus difference signal AFo with less focus fluctuation can be obtained.
As a result, the optical pickup device 40 capable of reducing the disturbance amplitude at the time of seeking can be made simple and inexpensive.

【００６５】また、和信号（ａ＋ｂ＋ｃ＋ｄ）の交流成
分を定数倍して、フォーカス差信号Ｆｏに加算している
ので、フォーカス差信号Ｆｏの揺らぎを適切にキャンセ
ルすることができる。Further, since the AC component of the sum signal (a + b + c + d) is multiplied by a constant and added to the focus difference signal Fo, the fluctuation of the focus difference signal Fo can be appropriately canceled.

【００６６】図１３は、本発明の光ピックアップ装置の
第３の実施の形態を示す図であり、本実施の形態は、フ
ォーカス差信号の揺らぎを補正するとともに、再生分解
能の良好な２値出力を得るもので、請求項５、６に対応
するものである。FIG. 13 is a diagram showing a third embodiment of the optical pickup device according to the present invention. This embodiment corrects the fluctuation of the focus difference signal and outputs a binary signal with good reproduction resolution. Which corresponds to claims 5 and 6.

【００６７】なお、本実施の形態は、上記第１の実施の
形態と同様の光ピックアップ装置に適用したものであ
り、本実施の形態の説明において、第１の実施の形態の
光ピックアップ装置と同様の構成部分には、同一の符号
を付して、その詳細な説明を省略する。The present embodiment is applied to the same optical pickup device as that of the first embodiment. In the description of this embodiment, the optical pickup device of the first embodiment is different from that of the first embodiment. The same components are denoted by the same reference numerals, and detailed description thereof will be omitted.

【００６８】図１３において、光ピックアップ装置５０
は、受光素子１１、演算回路１２、１３、ＡＣ結合回路
１４、定数倍回路１５、加算回路１６、波形等化回路５
１及び２値化回路５２等を備えており、受光素子１１
は、上記第１の実施の形態の受光素子１１と同様のもの
である。In FIG. 13, the optical pickup device 50
Are a light receiving element 11, arithmetic circuits 12, 13, an AC coupling circuit 14, a constant multiplying circuit 15, an adding circuit 16, a waveform equalizing circuit 5,
The light receiving element 11 includes a 1 and 2 binarizing circuit 52 and the like.
Is similar to the light receiving element 11 of the first embodiment.

【００６９】受光素子１１の全ての受光領域１１Ａ〜１
１Ｈの出力ａ〜ｈが演算回路１２に入力され、受光素子
１１の０次受光領域１１Ａ〜１１Ｄの出力ａ〜ｄが演算
回路１３に入力されている。All light receiving areas 11A-1 of light receiving element 11
Outputs a to h of 1H are input to the arithmetic circuit 12, and outputs a to d of the zero-order light receiving areas 11A to 11D of the light receiving element 11 are input to the arithmetic circuit 13.

【００７０】演算回路１２は、第１の実施の形態と同様
に、受光素子１１の全ての受光領域１１Ａ〜１１Ｈの出
力ａ〜ｈから（ａ＋ｅ＋ｃ＋ｇ）−（ｆ＋ｂ＋ｄ＋ｈ）
を演算して、フォーカス差信号Ｆｏを加算回路１６に出
力する。As in the first embodiment, the arithmetic circuit 12 calculates (a + e + c + g)-(f + b + d + h) from the outputs a to h of all the light receiving areas 11A to 11H of the light receiving element 11.
And outputs the focus difference signal Fo to the addition circuit 16.

【００７１】演算回路１３は、第１の実施の形態と同様
に、受光素子１１の０次受光領域１１Ａ〜１１Ｄの出力
ａ〜ｄを加算して、和信号（ａ＋ｂ＋ｃ＋ｄ）を生成
し、和信号（ａ＋ｂ＋ｃ＋ｄ）をＡＣ結合回路１４及び
波形等化回路５１に出力する。As in the first embodiment, the arithmetic circuit 13 adds the outputs a to d of the zero-order light receiving areas 11A to 11D of the light receiving element 11 to generate a sum signal (a + b + c + d), (A + b + c + d) is output to the AC coupling circuit 14 and the waveform equalization circuit 51.

【００７２】ＡＣ結合回路１４及び定数倍回路１５は、
上記第１の実施の形態と同様であり、演算回路１３の算
出した和信号の交流成分を取り出し、定数倍して、加算
回路１６に出力する。The AC coupling circuit 14 and the constant multiplication circuit 15
As in the first embodiment, the AC component of the sum signal calculated by the arithmetic circuit 13 is extracted, multiplied by a constant, and output to the adding circuit 16.

【００７３】加算回路１６は、演算回路１２から入力さ
れるフォーカス差信号Ｆｏと定数倍回路１５から入力さ
れる和信号（ａ＋ｂ＋ｃ＋ｄ）の交流成分の定数倍を加
算して、補正フォーカス差信号ＡＦｏとして出力する。The addition circuit 16 adds a constant multiple of the AC component of the focus difference signal Fo input from the arithmetic circuit 12 and the sum signal (a + b + c + d) input from the constant multiplication circuit 15 to obtain a corrected focus difference signal AFo. Output.

【００７４】波形等化回路５１は、演算回路１３から入
力される和信号（ａ＋ｂ＋ｃ＋ｄ）を波形整形して２値
化回路５２に出力する。２値化回路５２は、演算回路１
３が算出して波形等化回路１５で波形整形された和信号
（ａ＋ｂ＋ｃ＋ｄ）を２値化し、２値化信号を出力す
る。The waveform equalization circuit 51 shapes the waveform of the sum signal (a + b + c + d) input from the arithmetic circuit 13 and outputs the resultant signal to the binarization circuit 52. The binarizing circuit 52 includes the arithmetic circuit 1
3 is binarized from the sum signal (a + b + c + d) which has been calculated and waveform-shaped by the waveform equalization circuit 15, and outputs a binarized signal.

【００７５】したがって、本実施の形態の光ピックアッ
プ装置５０によれば、第１の実施の形態と同様に、非点
収差法の揺らぐフォーカス差信号Ｆｏをトラックパター
ンを含まない０次受光領域１１Ａ〜１１Ｄの和信号（ａ
＋ｂ＋ｃ＋ｄ）の交流成分で補正し、フォーカスゆらぎ
の少ない補正フォーカス差信号ＡＦｏを得ることがで
き、シーク時の外乱振幅を低減させることができるとと
もに、信頼性の高い２値化信号を得ることができ、再生
の分解能を向上させることができる。Therefore, according to the optical pickup device 50 of the present embodiment, as in the case of the first embodiment, the fluctuating focus difference signal Fo of the astigmatism method is transmitted to the zero-order light receiving regions 11A to 11A which do not include the track pattern. 11D sum signal (a
+ B + c + d), it is possible to obtain a corrected focus difference signal AFo with less focus fluctuation, to reduce the disturbance amplitude at the time of seek, and to obtain a highly reliable binary signal. , The resolution of reproduction can be improved.

【００７６】すなわち、図３に示したように、光情報記
録媒体３０は、トラック３１列により、トラック３１と
直交する方向（ラジアル方向）に回折格子として作用す
るとともに、記録面に形成されたピット列により、トラ
ック３１と平行な方向（タンジェンシャル方向）に回折
格子として作用する。That is, as shown in FIG. 3, the optical information recording medium 30 acts as a diffraction grating in a direction (radial direction) orthogonal to the tracks 31 by the tracks 31 and the pits formed on the recording surface. The rows act as diffraction gratings in a direction parallel to the track 31 (tangential direction).

【００７７】いま、光情報記録媒体３０のタンジェンシ
ャル方向の回折格子としての作用のみに着目すると、記
録面のピットによって回折された０次光は、上述のよう
に、受光素子１１の中央に入射し、＋１次光と−１次光
は、受光素子１１のタンジェンシャル方向の４つの０次
受光領域１１Ａ、１１Ｄ及び０次受光領域１１Ｂ、１１
Ｃに主に入射する。したがって、＋１次光と−１次光
は、０次受光領域１１Ａ、１１Ｄ及び０次受光領域１１
Ｂ、１１Ｃにおいて干渉し、主としてこの４つの０次受
光領域１１Ａ、１１Ｂ、１１Ｃ、１１Ｄに再生信号の強
弱が現れる。すなわち、光情報記録媒体３０のピットに
よって反射された反射光の受光素子１１への収束スポッ
ト２１は、図４に示したように、光情報記録媒体３０の
トラックパターン２１ｉ、２１ｊと同様のパターン２１
ｇ、２１ｈとして、光情報記録媒体３０のトラックパタ
ーン２１ｉ、２１ｊと直交する方向に入射される。そし
て、受光素子１１の０次受光領域１１Ａ、１１Ｂ、１１
Ｃ、１１Ｄには、ピットによる回折信号成分を多く含ん
だ反射光が照射され、０次受光領域１１Ａ、１１Ｂ、１
１Ｃ、１１Ｄは、この反射光の受光量に対応した出力
ａ、ｂ、ｃ、ｄを出力する。Focusing only on the function of the optical information recording medium 30 as a diffraction grating in the tangential direction, the zero-order light diffracted by the pits on the recording surface enters the center of the light receiving element 11 as described above. The + 1st-order light and the -1st-order light are divided into four 0th-order light receiving areas 11A and 11D and 0th-order light receiving areas 11B and 11B in the tangential direction of the light receiving element 11.
It is mainly incident on C. Therefore, the +1 order light and the −1 order light are divided into the 0 order light receiving regions 11A and 11D and the 0 order light receiving region 11
B and 11C, and the intensity of the reproduced signal mainly appears in the four zero-order light receiving regions 11A, 11B, 11C and 11D. That is, as shown in FIG. 4, the converging spot 21 of the reflected light reflected by the pits of the optical information recording medium 30 on the light receiving element 11 has the same pattern 21 as the track patterns 21i and 21j of the optical information recording medium 30.
g and 21h are incident in directions perpendicular to the track patterns 21i and 21j of the optical information recording medium 30. Then, the zero-order light receiving areas 11A, 11B, 11 of the light receiving element 11
C and 11D are irradiated with reflected light containing a large amount of diffraction signal components due to the pits, and the zero-order light receiving regions 11A, 11B, 1
1C and 11D output outputs a, b, c, and d corresponding to the amount of received reflected light.

【００７８】そして、光ピックアップ装置５０は、この
ピットによる回折信号成分を多く含んだ反射光の入射さ
れる０次受光領域１１Ａ、１１Ｂ、１１Ｃ、１１Ｄの出
力ａ、ｂ、ｃ、ｄの和信号（ａ＋ｂ＋ｃ＋ｄ）を波形整
形して、２値化しているので、Ｃ／Ｎ（再生分解能）が
高く、信頼性の高い２値化信号を安価に得ることができ
る。The optical pickup device 50 outputs the sum signal of the outputs a, b, c, and d of the zero-order light receiving regions 11A, 11B, 11C, and 11D on which the reflected light containing a large amount of the diffraction signal component due to the pit is incident. Since (a + b + c + d) is waveform-shaped and binarized, a highly reliable binarized signal having a high C / N (reproduction resolution) can be obtained at low cost.

【００７９】なお、上記実施の形態においては、受光素
子１１は、タンジェンシャル方向に平行なトラック方向
分割線１７とこのトラック方向分割線１７の中央の１点
Ｐで直交しトラック方向と直交する方向（ラジアル方
向）に延在するラジアル方向分割線１８により４等分さ
れ、この１点Ｐで交差し、略四角形の受光素子１１の対
角線方向に延在する分割線１９、２０により、さらに分
割されて、８分割されているが、受光素子としては、上
記実施の形態のものに限るものではなく、例えば、図１
４に示すように、受光素子６０は、タンジェンシャル方
向に平行なトラック方向分割線６１とこのトラック方向
分割線６１の中央の１点Ｐで直交しトラック方向分割線
１７と直交するラジアル方向分割線６２により、４等分
され、当該トラック方向分割線６１の１点Ｐとは異なる
所定の１点ｉを端点として略四角形の受光素子６０の角
方向に延在する２本の分割線６３、６４と、トラック方
向分割線６１の前記中央の１点Ｐを挟んで、点ｉと異な
る他の１点ｊを端点として受光素子６０の角方向に延在
する２本の分割線６５、６６と、により、８分割された
受光領域６０Ａ、６０Ｂ、６０Ｃ、６０Ｄ、６０Ｅ、６
０Ｆ、６０Ｇ、６０Ｈを有したもの（請求項４に対応す
るもの）であってもよい。In the above-described embodiment, the light receiving element 11 is arranged so that the light receiving element 11 is perpendicular to the track direction dividing line 17 and the center point P of the track direction dividing line 17 in the direction perpendicular to the track direction. The light receiving element 11 is divided into four equal parts by a radial dividing line 18 extending in the (radial direction), intersects at this point P, and is further divided by dividing lines 19 and 20 extending in a diagonal direction of the substantially square light receiving element 11. Thus, the light receiving element is divided into eight, but the light receiving element is not limited to the one in the above embodiment.
As shown in FIG. 4, the light receiving element 60 includes a track direction dividing line 61 parallel to the tangential direction and a radial direction dividing line orthogonal to the track direction dividing line 17 at one point P at the center of the track direction dividing line 61. 62, two dividing lines 63 and 64 extending in the angular direction of the substantially square light receiving element 60 with a predetermined point i different from one point P of the track direction dividing line 61 as an end point. Two division lines 65 and 66 extending in the angular direction of the light receiving element 60 with one point j different from the point i as an end point with the center point P of the track direction division line 61 interposed therebetween; , The light receiving areas 60A, 60B, 60C, 60D, 60E, 6
One having 0F, 60G, and 60H (corresponding to claim 4) may be used.

【００８０】この場合、光情報記録媒体３０の記録面に
照射されるスポット径がトラックピッチに対して相対的
に小さい場合に、受光素子６０に照射される収束スポッ
ト６７の±１次光６７ｉ、６７ｊが重なり合うが、受光
素子６０の受光領域６０Ａ、６０Ｂ、６０Ｃ、６０Ｄ、
６０Ｅ、６０Ｆ、６０Ｇ、６０Ｈを、上述のように分割
すると、図１４に示すように、０次受光領域である受光
領域６０Ａ、６０Ｂ、６０Ｃ、６０Ｄに±１次光６７
ｉ、６７ｊが入射されるのを低減させることができる。In this case, when the spot diameter applied to the recording surface of the optical information recording medium 30 is relatively small with respect to the track pitch, ± first order light 67i of the convergent spot 67 applied to the light receiving element 60, 67j overlap, but the light receiving areas 60A, 60B, 60C, 60D,
When the 60E, 60F, 60G, and 60H are divided as described above, as shown in FIG. 14, the ± first-order light 67 in the light-receiving regions 60A, 60B, 60C, and 60D that are the zero-order light-receiving regions.
i, 67j can be reduced.

【００８１】したがって、この受光素子６０を上記各実
施の形態に適用することにより、±１次光６７ｉ、６７
ｊが重なりあう場合にも、フォーカス差信号Ｆｏを適切
に補正した補正フォーカス差信号ＡＦｏを得ることがで
き、また、再生分解能の高い２値化出力を得ることがで
きる。Therefore, by applying this light receiving element 60 to each of the above-described embodiments, the ± first-order lights 67i, 67i
Even when j overlaps with each other, it is possible to obtain a corrected focus difference signal AFo obtained by appropriately correcting the focus difference signal Fo, and it is also possible to obtain a binarized output having a high reproduction resolution.

【００８２】また、上記各実施の形態においては、受光
素子１１、６０上に結ばれる合焦時のスポット２１、６
７の形状が、図３及び図１４に示したように、略円形で
ある場合について説明した。これは、通常の非点収差法
の場合には、適切に適用することができるが、フォーカ
ス感度を上げた非点収差法等においては、図１５に示す
ように、例えば、受光素子１１上に結ばれる合焦時のス
ポット７０の形状が、楕円形状に変化する。In each of the above embodiments, the focused spots 21 and 6 formed on the light receiving elements 11 and 60 are focused.
The case where the shape of No. 7 is substantially circular as shown in FIGS. 3 and 14 has been described. This can be appropriately applied in the case of the ordinary astigmatism method, but in the astigmatism method or the like in which the focus sensitivity is increased, for example, as shown in FIG. The shape of the focused spot 70 at the time of focusing changes to an elliptical shape.

【００８３】このように、スポット７０の形状が楕円形
状であると、受光素子１１について図１５に示すよう
に、トラックパターン７０ｉは、受光領域１１Ｂに侵入
し、トラックパターン７０ｊは、受光領域１１Ｄに侵入
するようになる。そのため、±１次光の干渉による信号
成分は、受光領域１１Ｄよりも受光領域１１Ａに、受光
領域１１Ｂよりも受光領域１１Ｃに多く含まれるように
なる。このような場合、２値化信号としては、４つの受
光領域１１Ａ、１１Ｂ、１１Ｃ、１１Ｄの各出力ａ、
ｂ、ｃ、ｄの和信号（ａ＋ｂ＋ｃ＋ｄ）として算出する
よりも、楕円形状のスポット７０の傾いた方の２つの受
光領域１１Ａ、１１Ｃ、あるいは、２つの受光領域１１
Ｂ、１１Ｄ、図１５の場合では、受光領域１１Ａ、１１
Ｃの出力ａ、ｃの和（ａ＋ｃ）として和信号（ａ＋ｃ）
を算出する方が、Ｃ／Ｎが向上する。As described above, when the spot 70 has an elliptical shape, the track pattern 70i enters the light receiving region 11B and the track pattern 70j enters the light receiving region 11D as shown in FIG. Get invaded. Therefore, the signal components due to the interference of the ± first-order light are included more in the light receiving region 11A than in the light receiving region 11D and in the light receiving region 11C than in the light receiving region 11B. In such a case, as the binarized signal, each output a of the four light receiving areas 11A, 11B, 11C, 11D,
Rather than calculating the sum signal (a + b + c + d) of b, c, and d, the two light receiving regions 11A and 11C or the two light receiving regions 11 on the inclined elliptical spot 70 are inclined.
B, 11D, in the case of FIG.
Sum signal (a + c) as the sum (a + c) of outputs a and c of C
Is calculated, C / N is improved.

【００８４】また、この楕円形状のスポット７０の傾き
方向は、光ピックアップ装置の設計時に決定されるた
め、上記２つの２つの受光領域１１Ａ、１１Ｃ、あるい
は、２つの受光領域１１Ｂ、１１Ｄのいずれの和信号を
取るかは、設計時に設定する。Since the inclination direction of the elliptical spot 70 is determined at the time of designing the optical pickup device, any one of the two light receiving regions 11A and 11C or the two light receiving regions 11B and 11D is used. Whether to take the sum signal is set at the time of design.

【００８５】そこで、設計時に設定した受光素子１１の
２つの受光領域１１Ａ、１１Ｃ、あるいは、２つの受光
領域１１Ｂ、１１Ｄのいずれかの和信号を図１３に示し
た演算回路１３で算出して、２値化信号とすることによ
り、Ｃ／Ｎ（再生分解能）が高く、信頼性の高い２値化
信号を得ることができ、安価に再生の分解能を向上させ
ることができる。Therefore, the sum signal of either one of the two light receiving areas 11A and 11C or two light receiving areas 11B and 11D of the light receiving element 11 set at the time of design is calculated by the arithmetic circuit 13 shown in FIG. By using a binary signal, a highly reliable binary signal having a high C / N (reproduction resolution) can be obtained, and the reproduction resolution can be improved at low cost.

【００８６】以上、本発明者によってなされた発明を好
適な実施の形態に基づき具体的に説明したが、本発明は
上記のものに限定されるものではなく、その要旨を逸脱
しない範囲で種々変更可能であることはいうまでもな
い。As described above, the invention made by the present inventor has been specifically described based on the preferred embodiments. However, the present invention is not limited to the above, and various modifications can be made without departing from the gist of the invention. It goes without saying that it is possible.

【００８７】[0087]

【発明の効果】請求項１記載の発明の光ピックアップ装
置によれば、受光素子を８つの受光領域に分割し、当該
８つの受光領域のうち、０次光を主に受光する４つの０
次受光領域の受光量をその位置関係において一方向回り
にａ、ｂ、ｃ、ｄとし、０次光と±１次光を主に受光す
る４つの１次受光領域の受光量をその位置関係において
ｅ、ｆ、ｇ、ｈとしたとき、（ａ＋ｅ＋ｃ＋ｇ）−（ｆ
＋ｂ＋ｄ＋ｈ）によりフォーカス差信号を求め、このフ
ォーカス差信号に０次受光領域の各受光量の和（ａ＋ｂ
＋ｃ＋ｄ）の和信号の交流成分を加算して補正フォーカ
ス差信号を生成しているので、非点収差法の揺らぎのあ
るフォーカス差信号をトラックパターンを含まない０次
受光領域の和信号の交流成分で補正することができ、フ
ォーカスゆらぎの少ない補正フォーカス差信号を得るこ
とができる。その結果、シーク時の外乱振幅を低減させ
ることができる。According to the optical pickup device of the first aspect of the present invention, the light receiving element is divided into eight light receiving areas, and four light receiving areas mainly receiving the zero-order light among the eight light receiving areas.
The received light amount of the next light receiving area is a, b, c, and d around one direction in the positional relationship, and the received light amount of the four primary light receiving areas that mainly receive the 0th order light and the ± 1st order light is the positional relationship. Where e, f, g, and h are (a + e + c + g)-(f
+ B + d + h) to obtain a focus difference signal. The focus difference signal is added to the sum (a + b) of the respective light receiving amounts of the zero-order light receiving region.
+ C + d) to generate a corrected focus difference signal by adding the AC component of the sum signal, the focus difference signal having fluctuation in the astigmatism method is converted to the AC component of the sum signal of the zero-order light receiving area not including the track pattern. And a corrected focus difference signal with little focus fluctuation can be obtained. As a result, the disturbance amplitude during the seek can be reduced.

【００８８】請求項２記載の発明の光ピックアップ装置
によれば、受光素子を８つの受光領域に分割し、当該８
つの受光領域のうち、０次光を主に受光する４つの０次
受光領域の受光量をその位置関係において一方向回りに
ａ、ｂ、ｃ、ｄとし、０次光と±１次光を主に受光する
４つの１次受光領域の受光量をその位置関係において
ｅ、ｆ、ｇ、ｈとしたとき、（ｅ＋ｇ）−（ｆ＋ｈ）に
よりフォーカス差信号を求め、このフォーカス差信号に
０次受光領域の各受光量の和（ａ＋ｂ＋ｃ＋ｄ）の和信
号の交流成分を加算して補正フォーカス差信号を生成し
ているので、簡単な回路構成で非点収差法の揺らぎのあ
るフォーカス差信号をトラックパターンを含まない０次
受光領域の和信号の交流成分で補正することができ、フ
ォーカスゆらぎの少ない補正フォーカス差信号を得るこ
とができる。その結果、簡単な構成で、かつ、安価にシ
ーク時の外乱振幅を低減させることができる。According to the optical pickup device of the present invention, the light receiving element is divided into eight light receiving areas.
Of the four light receiving areas, the light receiving amounts of the four zero-order light receiving areas that mainly receive the zero-order light are a, b, c, and d around one direction in the positional relationship, and the zero-order light and the ± first-order light are Assuming that the light receiving amounts of the four primary light receiving areas mainly receiving light are e, f, g, and h in the positional relationship, a focus difference signal is obtained from (e + g)-(f + h). Since the corrected focus difference signal is generated by adding the AC component of the sum signal (a + b + c + d) of the light receiving amounts of the respective light receiving areas, the focus difference signal having the fluctuation of the astigmatism method can be tracked with a simple circuit configuration. Correction can be performed using the AC component of the sum signal of the zero-order light receiving area that does not include the pattern, and a corrected focus difference signal with less focus fluctuation can be obtained. As a result, the disturbance amplitude during the seek can be reduced with a simple configuration and at a low cost.

【００８９】請求項３記載の発明の光ピックアップ装置
によれば、受光素子を、該受光素子上のトラックの像と
平行に配置されたトラック方向分割線と、該トラック方
向分割線上の所定の１点で当該トラック方向分割線と所
定角度で交わる３本の分割線と、で４つの０次受光領域
と、４つの１次受光領域と、の８つの受光領域に分割し
ているので、受光素子を簡単な分割形状で８つの受光領
域に分割して、フォーカスゆらぎの少ない補正フォーカ
ス差信号を得ることができ、簡単な構成で、かつ、安価
な受光素子によりシーク時の外乱振幅を低減させること
ができる。According to the optical pickup device of the third aspect of the present invention, the light receiving element is divided into a track direction dividing line arranged in parallel with an image of a track on the light receiving element, and a predetermined one on the track direction dividing line. Since the light is divided into eight light receiving areas of four zero-order light receiving areas and four primary light receiving areas by three dividing lines intersecting the track direction dividing line at a predetermined angle at a point, the light receiving element Can be divided into eight light receiving areas with a simple divided shape to obtain a corrected focus difference signal with little focus fluctuation. The disturbance amplitude during seek can be reduced with a simple configuration and an inexpensive light receiving element. Can be.

【００９０】請求項４記載の発明の光ピックアップ装置
によれば、受光素子を、該受光素子上のトラックの像と
平行に配置されたトラック方向分割線と、該トラック方
向分割線上の所定の直交点で該トラック方向分割線と直
交する直交分割線と、該トラック方向分割線上の直交点
とは異なる他の所定の１点を端点とした２本の分割線
と、該トラック方向分割線上の直交点を挟んで前記所定
の１点と反対側の所定の１点を端点とした２本の分割線
と、で４つの０次受光領域と、４つの１次受光領域と、
の８つの受光領域に分割しているので、トラックパター
ンが受光素子上で重なり合う場合にも、０次受光領域と
１次受光領域とを適切に分割して、フォーカスゆらぎの
少ない補正フォーカス差信号を得ることができ、安価に
シーク時の外乱振幅を低減させることができる。According to the optical pickup device of the fourth aspect of the present invention, the light receiving element is formed by dividing a track direction dividing line arranged in parallel with an image of a track on the light receiving element and a predetermined orthogonal line on the track direction dividing line. An orthogonal dividing line orthogonal to the track direction dividing line at a point, two dividing lines having another predetermined point different from the orthogonal point on the track direction dividing line as an end point, and an orthogonal dividing line on the track direction dividing line. Four zero-order light-receiving regions, four primary light-receiving regions, and two division lines having a predetermined point opposite to the predetermined one point as an end point across the point;
Even when the track patterns overlap on the light receiving element, the zero order light receiving area and the primary light receiving area are appropriately divided even if the track patterns overlap each other, and the corrected focus difference signal with less focus fluctuation can be obtained. Thus, the disturbance amplitude during the seek can be reduced at a low cost.

【００９１】請求項５記載の発明の光ピックアップ装置
によれば、受光素子の８つの受光領域のうち、０次光を
主に受光する０次受光領域の受光量の和を２値化してい
るので、フォーカスゆらぎの少ない補正フォーカス差信
号を得ることができ、安価にシーク時の外乱振幅を低減
させることができるとともに、０次光を受光する０次受
光領域の受光量から再生信号を生成することができ、再
生分解能を向上させることができる。According to the optical pickup device of the fifth aspect of the present invention, the sum of the light receiving amounts of the zero-order light receiving region mainly receiving the zero-order light among the eight light receiving regions of the light receiving element is binarized. Therefore, a corrected focus difference signal with less focus fluctuation can be obtained, the disturbance amplitude at the time of seek can be reduced at a low cost, and a reproduction signal is generated from the amount of light received in the zero-order light receiving region for receiving the zero-order light. And the reproduction resolution can be improved.

【００９２】請求項６記載の発明の光ピックアップ装置
によれば、受光素子の８つの受光領域のうち、０次光を
主に受光する４つの０次受光領域の受光量を、当該４つ
の受光領域の位置関係において一方向回りにａ、ｂ、
ｃ、ｄとしたとき、２つの受光量の和（ａ＋ｃ）あるい
は（ｂ＋ｄ）を２値化しているので、フォーカスゆらぎ
の少ない補正フォーカス差信号を得ることができ、安価
にシーク時の外乱振幅を低減させることができるととも
に、非点収差法の設計に応じた再生信号成分の高い２つ
の受光領域の受光量の和信号から再生信号を生成するこ
とができ、再生分解能を向上させることができる。According to the optical pickup device of the sixth aspect of the present invention, of the eight light receiving areas of the light receiving element, the light receiving amounts of the four zero order light receiving areas mainly receiving the zero order light are reduced by the four light receiving areas. In the positional relationship of the area, a, b,
When c and d, the sum (a + c) or (b + d) of the two received light amounts is binarized, so that a corrected focus difference signal with little focus fluctuation can be obtained, and the disturbance amplitude during seek can be reduced at low cost. In addition to being able to reduce, the reproduction signal can be generated from the sum signal of the light receiving amounts of the two light receiving regions having high reproduction signal components according to the design of the astigmatism method, and the reproduction resolution can be improved.

【図面の簡単な説明】[Brief description of the drawings]

【図１】本発明の光ピックアップ装置の第１の実施の形
態を適用した光ピックアップ装置の要部ブロック構成
図。FIG. 1 is a block diagram of a main part of an optical pickup device to which a first embodiment of an optical pickup device according to the present invention is applied.

【図２】図１の受光素子の平面図。FIG. 2 is a plan view of the light receiving element of FIG.

【図３】光情報記録媒体上の光スポットと受光素子上の
収束スポットの関係を示す図。FIG. 3 is a diagram showing a relationship between a light spot on an optical information recording medium and a convergent spot on a light receiving element.

【図４】図２の受光素子に略円形の収束スポットが照射
されている状態を示す受光素子の平面図。FIG. 4 is a plan view of the light receiving element in a state where a substantially circular convergent spot is irradiated on the light receiving element of FIG. 2;

【図５】一般的なフォーカス信号と０次受光領域の和信
号の関係を示す図。FIG. 5 is a diagram showing a relationship between a general focus signal and a sum signal of a zero-order light receiving area.

【図６】図１の光ピックアップ装置によるデフォーカス
が０．５μｍのときのフォーカス差信号Ｆｏと補正フォ
ーカス差信号ＡＦｏの関係を示す図。FIG. 6 is a diagram showing a relationship between a focus difference signal Fo and a corrected focus difference signal AFo when defocus by the optical pickup device of FIG. 1 is 0.5 μm.

【図７】図１の光ピックアップ装置によるデフォーカス
が１．０μｍのときのフォーカス差信号Ｆｏと補正フォ
ーカス差信号ＡＦｏの関係を示す図。7 is a diagram showing a relationship between a focus difference signal Fo and a corrected focus difference signal AFo when defocus by the optical pickup device of FIG. 1 is 1.0 μm.

【図８】図１の光ピックアップ装置によるデフォーカス
が１．５μｍのときのフォーカス差信号Ｆｏと補正フォ
ーカス差信号ＡＦｏの関係を示す図。8 is a diagram showing a relationship between a focus difference signal Fo and a corrected focus difference signal AFo when defocus by the optical pickup device of FIG. 1 is 1.5 μm.

【図９】本発明の光ピックアップ装置の第２の実施の形
態を適用した光ピックアップ装置の要部ブロック構成
図。FIG. 9 is a block diagram of a main part of an optical pickup device to which a second embodiment of the optical pickup device of the present invention is applied.

【図１０】図９の光ピックアップ装置によるデフォーカ
スが０．５μｍのときのフォーカス差信号Ｆｏと補正フ
ォーカス差信号ＡＦｏの関係を示す図。10 is a diagram showing a relationship between a focus difference signal Fo and a corrected focus difference signal AFo when defocus by the optical pickup device of FIG. 9 is 0.5 μm.

【図１１】図９の光ピックアップ装置によるデフォーカ
スが１．０μｍのときのフォーカス差信号Ｆｏと補正フ
ォーカス差信号ＡＦｏの関係を示す図。11 is a diagram showing a relationship between a focus difference signal Fo and a corrected focus difference signal AFo when defocus by the optical pickup device of FIG. 9 is 1.0 μm.

【図１２】図９の光ピックアップ装置によるデフォーカ
スが１．５μｍのときのフォーカス差信号Ｆｏと補正フ
ォーカス差信号ＡＦｏの関係を示す図。12 is a diagram illustrating a relationship between a focus difference signal Fo and a corrected focus difference signal AFo when defocus by the optical pickup device in FIG. 9 is 1.5 μm.

【図１３】本発明の光ピックアップ装置の第３の実施の
形態を適用した光ピックアップ装置の要部ブロック構成
図。FIG. 13 is a block diagram of a main part of an optical pickup device to which a third embodiment of the optical pickup device of the present invention is applied.

【図１４】受光素子の受光領域の他の分割例を示す受光
素子の平面図。FIG. 14 is a plan view of a light receiving element showing another example of dividing the light receiving area of the light receiving element.

【図１５】図２の受光素子に楕円形の収束スポットが照
射されている状態を示す受光素子の平面図。15 is a plan view of the light receiving element shown in FIG. 2, showing a state where the light receiving element is irradiated with an elliptical convergent spot.

【図１６】従来の光ピックアップ装置の要部正面図。FIG. 16 is a front view of a main part of a conventional optical pickup device.

【図１７】図１６の受光素子に略円形の収束スポットが
照射されている状態を示す受光素子の平面図。FIG. 17 is a plan view of the light receiving element shown in FIG. 16 in a state where a substantially circular convergent spot is irradiated on the light receiving element;

【図１８】図１６の受光素子に縦長の楕円形の収束スポ
ットが照射されている状態を示す受光素子の平面図。FIG. 18 is a plan view of the light receiving element in FIG. 16 showing a state in which a vertically long elliptical convergent spot is irradiated on the light receiving element.

【図１９】図１６の受光素子に横長の楕円形の収束スポ
ットが照射されている状態を示す受光素子の平面図。FIG. 19 is a plan view of the light receiving element shown in FIG. 16, showing a state where a horizontally long elliptical convergent spot is irradiated on the light receiving element;

【図２０】対物レンズが合焦位置を保ったまま光情報記
録媒体のトラックを横切る場合の理想的なフォーカス信
号を示す図。FIG. 20 is a diagram showing an ideal focus signal when an objective lens crosses a track of an optical information recording medium while maintaining a focus position.

【図２１】対物レンズが合焦位置を保ったまま光情報記
録媒体のトラックを横切る場合の外乱信号が重畳された
ときのフォーカス信号を示す図。FIG. 21 is a diagram illustrating a focus signal when a disturbance signal is superimposed when the objective lens crosses a track of the optical information recording medium while maintaining a focus position.

【符号の説明】[Explanation of symbols]

１０ 光ピックアップ装置 １１ 受光素子 １１Ａ、１１Ｂ、１１Ｃ、１１Ｄ ０次受光領域 １１Ｅ、１１Ｆ、１１Ｇ、１１Ｈ １次受光領域 １２、１３ 演算回路 １４ ＡＣ結合回路 １５ 定数倍回路 １６ 加算回路 １７ トラック方向分割線 １８ ラジアル方向分割線 １９、２０ 分割線 ２１ 収束スポット ２１ｉ、２１ｊ トラックパターン ａ、ｂ、ｃ、ｄ、ｅ、ｆ 出力 ３０ 光情報記録媒体 ３１ トラック ３２ 対物レンズ ３３ 光スポット ３４ ０次光 ３５ ＋１次光 ３６ −１次光 ３７ 直線 ａ、ｂ、ｃ、ｄ、ｅ、ｆ、ｇ、ｈ 出力 ４０ 光ピックアップ装置 ４１ 演算回路 ５０ 光ピックアップ装置 ５１ 波形等化回路 ５２ ２値化回路 ６０ 受光素子 ６０Ａ〜６０Ｈ 受光領域 ６１ トラック方向分割線 ６２ ラジアル方向分割線 ６３、６４、６５、６６ 分割線 ６７ 収束スポット ６７ｉ、６７ｊ ±１次光 ７０ スポット ７０ｉ、７０ｊ トラックパターン DESCRIPTION OF SYMBOLS 10 Optical pick-up apparatus 11 Light receiving element 11A, 11B, 11C, 11D 0th-order light-receiving area 11E, 11F, 11G, 11H Primary light-receiving area 12, 13 Operation circuit 14 AC coupling circuit 15 Constant multiplication circuit 16 Addition circuit 17 Track direction division line DESCRIPTION OF SYMBOLS 18 Radial dividing line 19, 20 Dividing line 21 Convergent spot 21i, 21j Track pattern a, b, c, d, e, f Output 30 Optical information recording medium 31 Track 32 Objective lens 33 Optical spot 34 0th order light 35 + 1st order Light 36-primary light 37 straight line a, b, c, d, e, f, g, h output 40 optical pickup device 41 arithmetic circuit 50 optical pickup device 51 waveform equalization circuit 52 binarization circuit 60 light receiving element 60A- 60H Light receiving area 61 Track direction dividing line 62 Radial direction dividing line 63, 64, 65 , 66 Division line 67 Convergent spot 67i, 67j ± primary light 70 Spot 70i, 70j Track pattern

Claims (6)

【特許請求の範囲】[Claims] 【請求項１】光源からの光をトラックを有する情報記録
媒体上に集光し、当該光情報記録媒体からの反射光に光
学系により前記トラックに対して略４５度方向の非点収
差を与えて、受光素子に集光照射する光ピックアップ装
置において、前記受光素子は、前記トラックからの前記
反射光のうち、０次光を主に受光する位置に配置された
４つの０次受光領域と、０次光と＋１次光または０次光
と−１次光を受光する位置に配置された４つの１次受光
領域と、の８つの受光領域を有し、前記０次受光領域の
受光量を当該４つの０次受光領域の位置関係において一
方向回りにａ、ｂ、ｃ、ｄとし、前記１次受光領域の受
光量を当該４つの１次受光領域の位置関係において一方
向回りにｅ、ｆ、ｇ、ｈとしたとき、（ａ＋ｅ＋ｃ＋
ｇ）−（ｆ＋ｂ＋ｄ＋ｈ）を演算してフォーカス差信号
を生成するフォーカス差信号演算手段と、（ａ＋ｂ＋ｃ
＋ｄ）を演算する和信号演算手段と、前記和信号演算手
段の演算した和信号の交流成分を取り出す交流成分取出
手段と、前記フォーカス差信号演算手段の演算したフォ
ーカス差信号と前記交流成分取出手段の取り出した前記
和信号の交流成分を加算して補正フォーカス差信号を生
成する加算手段と、を備えたことを特徴とする光ピック
アップ装置。An optical system focuses light from a light source onto an information recording medium having a track, and imparts astigmatism in a direction substantially 45 degrees to the track to the reflected light from the optical information recording medium by an optical system. In the optical pickup device for condensing and irradiating the light receiving element, the light receiving element includes four 0-order light receiving areas arranged at positions mainly receiving 0 order light among the reflected light from the track; It has eight light receiving areas, that is, four primary light receiving areas arranged at positions for receiving the 0th order light and the + 1st order light or the 0th order light and the -1st order light. In the positional relationship between the four zero-order light receiving regions, a, b, c, and d are set around one direction, and the light receiving amount of the primary light receiving region is set at e, around one direction in the positional relationship between the four primary light receiving regions. f, g, h, (a + e + c +
g)-(f + b + d + h) to calculate a focus difference signal calculating means, and (a + b + c)
+ D), an AC component extracting means for extracting an AC component of the sum signal calculated by the sum signal calculating means, a focus difference signal calculated by the focus difference signal calculating means, and the AC component extracting means. And an adding means for adding the AC component of the sum signal extracted above to generate a corrected focus difference signal. 【請求項２】光源からの光をトラックを有する情報記録
媒体上に集光し、当該光情報記録媒体からの反射光に光
学系により前記トラックに対して略４５度方向の非点収
差を与えて、受光素子に集光照射する光ピックアップ装
置において、前記受光素子は、前記トラックからの前記
反射光のうち、０次光を主に受光する位置に配置された
４つの０次受光領域と、０次光と＋１次光または０次光
と−１次光を受光する位置に配置された４つの１次受光
領域と、の８つの受光領域を有し、前記０次受光領域の
受光量を当該４つの０次受光領域の位置関係において一
方向回りにａ、ｂ、ｃ、ｄとし、前記１次受光領域の受
光量を当該４つの１次受光領域の位置関係において一方
向回りにｅ、ｆ、ｇ、ｈとしたとき、（ｅ＋ｇ）−（ｆ
＋ｈ）を演算してフォーカス差信号を生成するフォーカ
ス差信号演算手段と、（ａ＋ｂ＋ｃ＋ｄ）を演算する和
信号演算手段と、前記和信号演算手段の演算した和信号
のの交流成分を取り出す交流成分取出手段と、前記フォ
ーカス差信号演算手段の演算したフォーカス差信号と前
記交流成分取出手段の取り出した前記和信号の交流成分
を加算して補正フォーカス差信号を生成する加算手段
と、を備えたことを特徴とする光ピックアップ装置。2. A light beam from a light source is converged on an information recording medium having a track, and astigmatism of approximately 45 degrees is given to the track by an optical system to the reflected light from the optical information recording medium. In the optical pickup device for condensing and irradiating the light receiving element, the light receiving element includes four 0-order light receiving areas arranged at positions mainly receiving 0 order light among the reflected light from the track; It has eight light receiving areas, that is, four primary light receiving areas arranged at positions for receiving the 0th order light and the + 1st order light or the 0th order light and the -1st order light. In the positional relationship between the four zero-order light receiving regions, a, b, c, and d are set around one direction, and the light receiving amount of the primary light receiving region is set at e, around one direction in the positional relationship between the four primary light receiving regions. f, g, h, (e + g)-(f
+ H), a focus difference signal calculation means for generating a focus difference signal, a sum signal calculation means for calculating (a + b + c + d), and an AC component extraction for extracting an AC component of the sum signal calculated by the sum signal calculation means. Means, and an addition means for adding a focus difference signal calculated by the focus difference signal calculation means and an AC component of the sum signal extracted by the AC component extraction means to generate a corrected focus difference signal. An optical pickup device characterized by the following. 【請求項３】前記受光素子は、該受光素子上の前記トラ
ックの像と平行に配置されたトラック方向分割線と、該
トラック方向分割線上の所定の１点で当該トラック方向
分割線と所定角度で交わる３本の分割線と、により、前
記トラックからの前記反射光のうち、前記０次光を主に
受光する位置に配置された前記４つの０次受光領域と、
前記０次光と前記＋１次光または前記０次光と前記−１
次光を受光する位置に配置された前記４つの１次受光領
域と、の８つの受光領域に分割されていることを特徴と
する請求項１または請求項２記載の光ピックアップ装
置。3. A light receiving element comprising: a track direction dividing line disposed in parallel with an image of the track on the light receiving element; and a predetermined angle on the track direction dividing line at a predetermined point on the track direction dividing line. With the three division lines intersecting with each other, among the reflected light from the track, the four zero-order light receiving regions arranged at positions mainly receiving the zero-order light,
The 0-order light and the + 1-order light or the 0-order light and the -1
3. The optical pickup device according to claim 1, wherein the optical pickup device is divided into eight light receiving regions of the four primary light receiving regions arranged at positions where the next light is received. 【請求項４】前記受光素子は、該受光素子上の前記トラ
ックの像と平行に配置されたトラック方向分割線と、該
トラック方向分割線上の所定の直交点で該トラック方向
分割線と直交する直交分割線と、該トラック方向分割線
上の前記直交点とは異なる他の所定の１点を端点とした
２本の分割線と、該トラック方向分割線上の前記直交点
を挟んで前記所定の１点と反対側の所定の１点を端点と
した２本の分割線と、により、前記トラックからの前記
反射光のうち、前記０次光を主に受光する位置に配置さ
れた前記４つの０次受光領域と、前記０次光と前記＋１
次光または前記０次光と前記−１次光を受光する位置に
配置された前記４つの１次受光領域と、の８つの受光領
域に分割されていることを特徴とする請求項１または請
求項２記載の光ピックアップ装置。4. The light receiving element is orthogonal to the track direction dividing line at a predetermined orthogonal point on the track direction dividing line and a track direction dividing line disposed in parallel with the image of the track on the light receiving element. An orthogonal dividing line, two dividing lines each having another predetermined point different from the orthogonal point on the track direction dividing line as an end point, and the predetermined one of the predetermined dividing points with the orthogonal point on the track direction dividing line interposed therebetween. Two divided lines having a predetermined point on the opposite side to a point as an end point, the four 0s arranged at positions mainly receiving the 0th-order light of the reflected light from the track. Next-order light receiving area, the zero-order light, and the +1
The light receiving region is divided into eight light receiving regions of the next light or the zero-order light and the four primary light-receiving regions arranged at positions for receiving the first-order light. Item 3. The optical pickup device according to Item 2. 【請求項５】前記光ピックアップ装置は、前記和信号演
算手段の演算結果を２値化する２値化手段、をさらに備
えたことを特徴とする請求項１から請求項４のいずれか
に記載の光ピックアップ装置。5. The optical pickup device according to claim 1, further comprising a binarizing unit for binarizing a calculation result of the sum signal calculating unit. Optical pickup device. 【請求項６】前記光ピックアップ装置は、（ａ＋ｃ）あ
るいは（ｂ＋ｄ）を演算する和信号演算手段と、前記和
信号演算手段の演算した（ａ＋ｃ）あるいは（ｂ＋ｄ）
の演算結果を２値化する２値化手段と、をさらに備えた
ことを特徴とする請求項１から請求項４のいずれかに記
載の光ピックアップ装置。6. The optical pickup device according to claim 1, wherein the sum signal calculating means calculates (a + c) or (b + d), and (a + c) or (b + d) calculated by the sum signal calculating means.
5. The optical pickup device according to claim 1, further comprising: a binarizing unit that binarizes the calculation result of (b).
JP8226048A 1996-08-08 1996-08-08 Optical pickup device Pending JPH1055552A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP8226048A JPH1055552A (en) 1996-08-08 1996-08-08 Optical pickup device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP8226048A JPH1055552A (en) 1996-08-08 1996-08-08 Optical pickup device

Publications (1)

Publication Number Publication Date
JPH1055552A true JPH1055552A (en) 1998-02-24

Family

ID=16838981

Family Applications (1)

Application Number Title Priority Date Filing Date
JP8226048A Pending JPH1055552A (en) 1996-08-08 1996-08-08 Optical pickup device

Country Status (1)

Country Link
JP (1) JPH1055552A (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100644581B1 (en) * 1999-10-30 2006-11-13 삼성전자주식회사 Tracking error signal detecting apparatus and reproducing signal detecting apparatus
JP2010079983A (en) * 2008-09-25 2010-04-08 Sanyo Electric Co Ltd Optical pickup device and optical disk device
JP2010080005A (en) * 2008-09-26 2010-04-08 Sanyo Electric Co Ltd Optical pickup device and optical disk device
JP2010170627A (en) * 2009-01-23 2010-08-05 Sanyo Electric Co Ltd Optical pickup device and optical disk device

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100644581B1 (en) * 1999-10-30 2006-11-13 삼성전자주식회사 Tracking error signal detecting apparatus and reproducing signal detecting apparatus
JP2010079983A (en) * 2008-09-25 2010-04-08 Sanyo Electric Co Ltd Optical pickup device and optical disk device
JP2010080005A (en) * 2008-09-26 2010-04-08 Sanyo Electric Co Ltd Optical pickup device and optical disk device
JP2010170627A (en) * 2009-01-23 2010-08-05 Sanyo Electric Co Ltd Optical pickup device and optical disk device

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