JPH1153748A - Tracking error signal detecting method, composite optical element using the method, optical pickup device using the element and optical recording/reproducing device - Google Patents
Tracking error signal detecting method, composite optical element using the method, optical pickup device using the element and optical recording/reproducing deviceInfo
- Publication number
- JPH1153748A JPH1153748A JP9206625A JP20662597A JPH1153748A JP H1153748 A JPH1153748 A JP H1153748A JP 9206625 A JP9206625 A JP 9206625A JP 20662597 A JP20662597 A JP 20662597A JP H1153748 A JPH1153748 A JP H1153748A
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- JP
- Japan
- Prior art keywords
- light
- order
- light receiving
- receiving unit
- light beam
- Prior art date
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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明はトラッキングエラー
信号検出方法及びこれを用いた複合光学素子及びこれを
用いた光学ピックアップ装置及び光記録再生装置に関
し、さらに詳しくは、異なる種類の光記録媒体に対応す
るトラッキングエラー信号検出方法及びこれを用いた複
合光学素子及びこれを用いた光学ピックアップ装置及び
光記録再生装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tracking error signal detecting method, a composite optical element using the same, and an optical pickup device and an optical recording / reproducing device using the same. The present invention relates to a tracking error signal detection method, a composite optical element using the same, an optical pickup device and an optical recording / reproducing device using the same.
【０００２】[0002]
【従来の技術】ＲＯＭ（Ｒｅａｄ Ｏｎｌｙ Ｍｅｍｏ
ｒｙ）ディスクやＲＡＭ（Ｒａｎｄｏｍ Ａｃｃｅｓｓ
Ｍｅｍｏｒｙ）等の光記録媒体に記録された情報を再
生する、あるいは光記録媒体に情報を記録する光記録再
生装置には、半導体レーザを光源とする光学ピックアッ
プ装置が用いられている。近年では光記録再生装置の小
型薄型化の要求とともに光学ピックアップ装置の小型薄
型化も求められており、この観点から光源である半導体
レーザと光記録媒体で反射された戻りの復路光ビームを
受光して光電変換する受光素子とを同一の半導体基板上
に一体的に構成した複合光学素子を用いた光学ピックア
ップ装置が注目されている。この複合光学素子を用いた
光学ピックアップ装置及び光記録再生装置の一例につい
て、光学ピックアップ装置の概略構成図である図６及び
光記録再生装置の概略構成図である図７を参照し、その
概略構成について説明する。2. Description of the Related Art ROM (Read Only Memory)
ry) Disk or RAM (Random Access)
2. Description of the Related Art An optical pickup device using a semiconductor laser as a light source is used in an optical recording / reproducing apparatus for reproducing information recorded on an optical recording medium such as a memory or the like or recording information on an optical recording medium. In recent years, along with the demand for smaller and thinner optical recording / reproducing devices, there has also been a demand for smaller and thinner optical pickup devices. From this viewpoint, a semiconductor laser as a light source and a return light beam returning from an optical recording medium are received. Attention has been focused on an optical pickup device using a composite optical element in which a light receiving element for performing photoelectric conversion is integrally formed on the same semiconductor substrate. An example of an optical pickup device and an optical recording / reproducing device using the composite optical element will be described with reference to FIG. 6 which is a schematic configuration diagram of the optical pickup device and FIG. 7 which is a schematic configuration diagram of the optical recording / reproducing device. Will be described.
【０００３】複合光学素子１は、図６に示したように、
半導体基板５に形成された一対の第一の受光素子３ａ及
び第二の受光素子３ｂと、この第一の受光素子３ａ及び
第二の受光素子３ｂ上に接着剤等により固着され、半導
体基板５の第一の受光素子３ａ及び第二の受光素子３ｂ
が形成された面とほぼ４５度傾斜する半透過反射面４ａ
とほぼ平行な高反射面４ｂとが形成されたビームスプリ
ッタ４と、半透過反射面４ａに対向する側の半導体基板
５上のスペーサ６上面に固着された半導体レーザ２で概
略構成されている。[0003] As shown in FIG.
A pair of the first light receiving element 3a and the second light receiving element 3b formed on the semiconductor substrate 5, and the first light receiving element 3a and the second light receiving element 3b are fixed on the first light receiving element 3a and the second light receiving element 3b by an adhesive or the like. First light receiving element 3a and second light receiving element 3b
Transflective surface 4a inclined at approximately 45 degrees with respect to the surface on which is formed
And a semiconductor laser 2 fixed to the upper surface of the spacer 6 on the semiconductor substrate 5 on the side opposite to the semi-transmissive reflection surface 4a.
【０００４】そして、複合光学素子１上には二軸アクチ
ュエータ等のサーボアクチュエータ７が配設されてい
る。例えば、サーボアクチュエータ７が二軸アクチュエ
ータである場合には、例えば図７に示したように、対物
レンズ７ａを保持した可動部７ｂが固定部７ｄから延設
された一対の平行バネ７ｃにより支持されており、可動
部７ｂには、ともに図示を省略するフォーカシングコイ
ル及びトラッキングコイルが固着されている。フォーカ
シングコイル及びトラッキングコイルは固定部７ｄに固
着されて鉄等の磁性材で構成され、ともに図示を省略す
るヨークと、このヨークに固着されたマグネットとで構
成された磁気回路の空隙部に配置される。フォーカシン
グコイル及びトラッキングコイルには、後に説明するフ
ォーカシングエラー信号及びトラッキングエラー信号に
基づく大きさと方向の電流が流され、対物レンズ７ａを
保持した可動部７ｂをフォーカシング方向及びトラッキ
ング方向に制御駆動する。そして、光学ピックアップ装
置は上記した複合光学素子１やサーボアクチュエータ７
等を接着剤やネジ等により光学ブロック１５に固着した
状態で概略構成されている。[0004] On the composite optical element 1, a servo actuator 7 such as a biaxial actuator is provided. For example, when the servo actuator 7 is a biaxial actuator, for example, as shown in FIG. 7, a movable portion 7b holding an objective lens 7a is supported by a pair of parallel springs 7c extending from a fixed portion 7d. A focusing coil and a tracking coil (both not shown) are fixed to the movable portion 7b. The focusing coil and the tracking coil are fixed to the fixed part 7d and are made of a magnetic material such as iron. Both are arranged in a gap of a magnetic circuit formed by a yoke (not shown) and a magnet fixed to the yoke. You. A current having a magnitude and direction based on a focusing error signal and a tracking error signal, which will be described later, is applied to the focusing coil and the tracking coil to control and drive the movable portion 7b holding the objective lens 7a in the focusing direction and the tracking direction. The optical pickup device is provided with the composite optical element 1 and the servo actuator 7 described above.
And the like are fixed to the optical block 15 with an adhesive or a screw.
【０００５】光記録再生装置は、例えば図７に示したよ
うに、光学ピックアップ装置が構成された光学ブロック
１５をトラッキング方向に案内するとともに、フォーカ
シング方向とトラッキング方向の何れの方向も規制する
メインガイド軸１０ａ、メインガイド軸１０ａとほぼ平
行であり、フォーカシング方向のみを規制するサブガイ
ド軸１０ｂ、光学ブロック１５をトラッキング方向に駆
動し、リニアモータ等で構成された移動手段の他、何れ
も図示を省略するが、光記録媒体８を回転させるスピン
ドルモータ、信号処理やシステムコントローラ等の回路
等で概略構成されている。図７は移動手段を一対のリニ
アモータで構成した一例であり、マグネット１１を固着
した外ヨーク１２と内ヨーク１３とで磁気回路を構成
し、光学ブロック１５に固着されたコイル１４の内側に
内ヨーク１３を挿通した事例である。As shown in FIG. 7, for example, an optical recording / reproducing apparatus guides an optical block 15 having an optical pickup device in a tracking direction, and regulates both a focusing direction and a tracking direction. The axis 10a, the sub-guide axis 10b, which is substantially parallel to the main guide axis 10a, restricts only the focusing direction, drives the optical block 15 in the tracking direction, and includes a moving means composed of a linear motor or the like. Although omitted, it is schematically composed of a spindle motor for rotating the optical recording medium 8, circuits for signal processing and a system controller, and the like. FIG. 7 shows an example in which the moving means is constituted by a pair of linear motors. A magnetic circuit is constituted by an outer yoke 12 to which a magnet 11 is fixed and an inner yoke 13, and an inner part is provided inside a coil 14 fixed to an optical block 15. This is a case where the yoke 13 is inserted.
【０００６】以下、光学系について再び図６を参照して
説明する。半導体レーザ２の発光面２ａから出射された
往路光ビーム（図中の一点鎖線）はビームスプリッタ４
の半透過反射面４ａで反射され、二軸アクチュエータ等
のサーボアクチュエータ７に具備された対物レンズ７ａ
により光記録媒体８の信号記録面に集光する。そして、
信号記録面で回折されて反射された復路光ビームは再び
対物レンズ７ａを透過して半透過反射面４ａからビーム
スプリッタ４内に導かれ、第一の受光素子３ａを照射す
る（図中の二点鎖線）。さらに、第一の受光素子３ａで
反射した復路光ビームは高反射面４ｂで反射されて第二
の受光素子３ｂを照射する。この第一の受光素子３ａ及
び第二の受光素子３ｂで光電変化した信号から、フォー
カシングエラー信号、トラッキングエラー信号及びＲＦ
信号等が検出される。このフォーカシングエラー信号、
トラッキングエラー信号及びＲＦ信号の検出法の一例に
ついて、図６におけるＢ方向からみた第一の受光素子３
ａ及び第二の受光素子３ｂの概略Ｂ矢視図である図８を
参照して説明する。Hereinafter, the optical system will be described again with reference to FIG. The outward light beam (dashed line in the drawing) emitted from the light emitting surface 2a of the semiconductor laser 2 is
Is reflected by the semi-transmissive reflection surface 4a of the objective lens 7a provided in the servo actuator 7 such as a biaxial actuator.
Converges on the signal recording surface of the optical recording medium 8. And
The return light beam diffracted and reflected on the signal recording surface again passes through the objective lens 7a, is guided into the beam splitter 4 from the semi-transmissive reflection surface 4a, and irradiates the first light receiving element 3a (see FIG. Chain line). Further, the return light beam reflected by the first light receiving element 3a is reflected by the high reflection surface 4b and irradiates the second light receiving element 3b. From the signals photoelectrically changed by the first light receiving element 3a and the second light receiving element 3b, a focusing error signal, a tracking error signal,
A signal or the like is detected. This focusing error signal,
Regarding an example of a method of detecting a tracking error signal and an RF signal, the first light receiving element 3 viewed from the direction B in FIG.
This will be described with reference to FIG. 8 which is a schematic view of the arrow a in FIG.
【０００７】第一の受光素子３ａ及び第二の受光素子３
ｂは何れも四分割された受光部を有している。そして、
第一の受光素子３ａに有する受光部をａ、ｂ、ｃ、ｄと
し、第二の受光素子３ｂに有する受光部をｅ、ｆ、ｇ、
ｈとすれば、フォーカシングエラー信号は（（ａｄ−ｂ
ｃ）−（ｅｈ−ｆｇ））で検出され、トラッキングエラ
ー信号は、例えばＴＰＰ法（Ｔｏｐ−ｈｏｌｄ ａｎｄ
Ｐｕｓｈ−Ｐｕｌｌ）と称される（ｃｄｇｈ−ａｂｅ
ｆ）−Ｋｔ（（ｃｄｇｈのミラーレベル）−（ａｂｅｆ
のミラーレベル）））で検出され（但し、Ｋｔはトラッ
キングエラー信号のオフセット量を調整する係数）、Ｒ
Ｆ信号はａｂｃｄｅｆｇｈで検出される。The first light receiving element 3a and the second light receiving element 3
Each of b has a four-divided light receiving unit. And
The light receiving portions of the first light receiving element 3a are a, b, c, d, and the light receiving portions of the second light receiving element 3b are e, f, g,
h, the focusing error signal is ((ad-b
c)-(eh-fg)), and the tracking error signal is, for example, TPP (Top-hold and)
Push-Pull) (cdgh-ab)
f) -Kt ((mirror level of cdgh)-(abef
(Kt is a coefficient for adjusting the offset amount of the tracking error signal), and R
The F signal is detected by abcdefgh.
【０００８】しかしながら、近年、光記録媒体には異な
るフォーマット、例えば、一回のみの記録が可能なＣＤ
−Ｒと称せらるもの、書き換え可能なＣＤ−ＲＷと称せ
られるものやＤＶＤ（Ｄｉｇｉｔａｌ Ｖｅｒｓａｔｉ
ｌｅ Ｄｉｓｋ）等が普及しはじめている。従って、上
記したトラッキングエラー信号の検出法の一例であるＴ
ＰＰ法を用いて上記した各種の光記録媒体８に記録され
た信号を再生する、あるいは各種の光記録媒体８に信号
を記録する光記録再生装置では、トラッキングエラー信
号のオフセット量調整係数であるＫｔを光記録媒体８の
種類毎に対応させた最適値に、例えばソフトを変更する
等を行わなければならなかった。In recent years, however, optical recording media have different formats, for example, CDs that can be recorded only once.
-R, rewritable CD-RW and DVD (Digital Versati)
le Disk) has begun to spread. Therefore, T, which is an example of the tracking error signal detection method described above, is used.
In an optical recording / reproducing apparatus which reproduces signals recorded on the various optical recording media 8 using the PP method or records signals on the various optical recording media 8, the offset amount adjustment coefficient of the tracking error signal is used. For example, the software has to be changed to an optimum value corresponding to Kt for each type of the optical recording medium 8.
【０００９】[0009]
【発明が解決しようとする課題】本発明の課題は、異な
る種類の光記録媒体に対してオフセットを生じないトラ
ッキングエラー信号検出方法を提供し、これを用いて小
型薄型化及び高信頼性化を図った複合光学素子及びこれ
を用いた光学ピックアップ装置及び光記録再生装置を提
供することである。SUMMARY OF THE INVENTION It is an object of the present invention to provide a tracking error signal detecting method which does not cause offset for different types of optical recording media, and which is used to reduce the size and thickness and improve the reliability. An object of the present invention is to provide a composite optical element, an optical pickup device and an optical recording / reproducing device using the same.
【００１０】[0010]
【課題を解決するための手段】上記課題を解決するため
に、請求項１の発明のトラッキングエラー信号検出方法
では、往路光ビームを光記録媒体に集光し、往路光ビー
ムが光記録媒体で回折されて戻る復路光ビームを受光素
子に受光してトラッキングエラー信号を検出するトラッ
キングエラー信号検出方法において、往路光ビームをブ
レーズ回折格子で回折して往路０次光と、プラス、マイ
ナスの何れか一方の往路１次光との二パターンのみに
し、復路光ビームの復路０次光のＰｕｓｈ−Ｐｕｌｌ信
号と、復路光ビームの復路１次光のＰｕｓｈ−Ｐｕｌｌ
信号との差信号に基づいてトラッキングエラー信号を検
出することを特徴とする。そして、望ましい実施態様
は、光記録媒体のトラックに対して往路０次光と往路１
次光とを（ｍ＋１／２）トラックずらし（但し、ｍは整
数）、受光素子は、少なくとも四分割された第一の受光
部、第二の受光部、第三の受光部及び第四の受光部を有
し、（往路光ビームの回折光，復路光ビームの回折光）
の組み合わせを（０次，０次）、（０次，１次）、（１
次，０次）とするとき、（０次，０次）を第一の受光部
と第二の受光部とに受光させて第一の差信号を生成し、
（０次，１次）及び（１次，０次）を第三の受光部と第
四の受光部とに受光させて第二の差信号を生成し、第一
の差信号と第二の差信号の定数倍との差信号に基づいて
トラッキングエラー信号を検出するものである。According to a first aspect of the present invention, there is provided a tracking error signal detecting method, wherein a forward light beam is converged on an optical recording medium, and the forward light beam is focused on the optical recording medium. In a tracking error signal detection method of detecting a tracking error signal by receiving a return light beam that is diffracted and returned by a light receiving element, the forward light beam is diffracted by a blazed diffraction grating, and the forward zero-order light, plus or minus. There are only two patterns, one of which is the outgoing primary light, and the other is the Push-Pull signal of the returning zero-order light of the returning optical beam and the Push-Pull of the returning primary light of the returning optical beam.
A tracking error signal is detected based on a difference signal from the signal. In a preferred embodiment, the forward 0th-order light and the forward 1
The next light is shifted by (m + ／) tracks (where m is an integer), and the light receiving element is a first light receiving unit, a second light receiving unit, a third light receiving unit, and a fourth light receiving unit divided into at least four parts. (Diffraction light of forward light beam, diffracted light of return light beam)
Are (0 order, 0 order), (0 order, 1 order), (1 order)
(0th order, 0th order), the (0th order, 0th order) is received by the first light receiving unit and the second light receiving unit to generate a first difference signal,
(0th order, 1st order) and (1st order, 0th order) are received by a third light receiving unit and a fourth light receiving unit to generate a second difference signal. A tracking error signal is detected based on a difference signal from a constant multiple of the difference signal.
【００１１】請求項３の発明の複合光学素子では、少な
くとも半導体基板上に形成された第一の受光素子及び第
二の受光素子と、半導体基板上に形成され、半導体基板
とほぼ垂直な発光面を有する半導体レーザと、第一の受
光素子及び第二の受光素子上に固着されるとともに、半
導体レーザの発光面から出射された往路光ビームを反射
し、反射されて戻る復路光ビームを第一の受光素子に導
く半透過反射面と、第一の受光素子上面で反射された復
路光ビームを反射して第二の受光素子に導く高反射面と
が形成されたビームスプリッタとを有する複合光学素子
において、往路光ビームを回折して往路０次光と、プラ
ス、マイナスの何れか一方の往路１次光との二パターン
のみにするとともに、往路光ビームが対物レンズを介し
て集光される光記録媒体のトラックに対して往路０次光
と往路１次光とを（ｍ＋１／２）トラックずらすブレー
ズ回折格子を半透過反射面と対物レンズとの間に配設し
（但し、ｍは整数）、第二の受光素子は、少なくとも四
分割された第一の受光部、第二の受光部、第三の受光部
及び第四の受光部を有し、（往路光ビームの回折光，復
路光ビームの回折光）の組み合わせを（０次，０次）、
（０次，１次）、（１次，０次）とするとき、（０次，
０次）の光を第一の受光部と第二の受光部とに受光させ
て第一の差信号を生成し、（０次，１次）及び（１次，
０次）の光を第三の受光部と第四の受光部とに受光させ
て第二の差信号を生成し、第一の差信号と第二の差信号
の定数倍との差信号に基づいてトラッキングエラー信号
を検出するように構成したことを特徴とする。According to a third aspect of the present invention, at least a first light receiving element and a second light receiving element formed on a semiconductor substrate, and a light emitting surface formed on the semiconductor substrate and substantially perpendicular to the semiconductor substrate. And a forward light beam that is fixed on the first light receiving element and the second light receiving element, reflects the outward light beam emitted from the light emitting surface of the semiconductor laser, and returns the reflected backward light beam to the first light receiving element. Composite optics having a semi-transmissive reflection surface leading to the light receiving element of the above and a high reflection surface reflecting the return light beam reflected on the upper surface of the first light receiving element and leading to the second light receiving element In the element, the outward light beam is diffracted into only two patterns, that is, the 0th-order light in the outward path and the positive or negative primary light in either one of the directions, and the outward light beam is condensed via the objective lens. Kouki A blazed diffraction grating that shifts the 0th-order light and the 1st-order light by (m + 1/2) tracks relative to the track of the medium is disposed between the semi-transmissive reflection surface and the objective lens (where m is an integer), The second light receiving element has at least a first light receiving unit, a second light receiving unit, a third light receiving unit, and a fourth light receiving unit which are divided into four parts. (0 order, 0 order)
(0 order, 1 order) and (1 order, 0 order), (0 order, 0 order,
The first (0th) light is received by the first light receiving unit and the second light receiving unit to generate a first difference signal, and the (0th, 1st) and (1st,
(0th) light is received by the third light-receiving unit and the fourth light-receiving unit to generate a second difference signal, which is converted into a difference signal between the first difference signal and a constant multiple of the second difference signal. The tracking error signal is detected based on the tracking error signal.
【００１２】請求項５の発明の光学ピックアップ装置で
は、少なくとも半導体基板上に形成された第一の受光素
子及び第二の受光素子と、半導体基板上に形成され、半
導体基板とほぼ垂直な発光面を有する半導体レーザと、
第一の受光素子及び第二の受光素子上に固着されるとと
もに、半導体レーザの発光面から出射された往路光ビー
ムを反射し、反射されて戻る復路光ビームを第一の受光
素子に導く半透過反射面と、第一の受光素子上面で反射
された復路光ビームを反射して第二の受光素子に導く高
反射面とが形成されたビームスプリッタとを有する複合
光学素子と、往路光ビームを光記録媒体に集光する対物
レンズとを有する光学ピックアップ装置において、複合
光学素子と対物レンズとの間に、往路光ビームを回折し
て往路０次光と、プラス、マイナスの何れか一方の往路
１次光との二パターンのみにするとともに、往路光ビー
ムが対物レンズを介して集光される光記録媒体のトラッ
クに対して往路０次光と往路１次光とを（ｍ＋１／２）
トラックずらすブレーズ回折格子を配設し（但し、ｍは
整数）、第二の受光素子は、少なくとも四分割された第
一の受光部、第二の受光部、第三の受光部及び第四の受
光部を有し、（往路光ビームの回折光，復路光ビームの
回折光）の組み合わせを（０次，０次）、（０次，１
次）、（１次，０次）とするとき、（０次，０次）の光
を第一の受光部と第二の受光部とに受光させて第一の差
信号を生成し、（０次，１次）及び（１次，０次）の光
を第三の受光部と第四の受光部とに受光させて第二の差
信号を生成し、第一の差信号と第二の差信号の定数倍と
の差信号に基づいてトラッキングエラー信号を検出する
ように構成したことを特徴とする。In an optical pickup device according to a fifth aspect of the present invention, at least a first light receiving element and a second light receiving element formed on a semiconductor substrate, and a light emitting surface formed on the semiconductor substrate and substantially perpendicular to the semiconductor substrate. A semiconductor laser having
A half light beam fixed to the first light receiving element and the second light receiving element, reflects the outward light beam emitted from the light emitting surface of the semiconductor laser, and guides the reflected return light beam to the first light receiving element. A composite optical element having a transmission / reflection surface, a beam splitter having a high reflection surface for reflecting the return light beam reflected by the upper surface of the first light receiving element and guiding the reflected light beam to the second light receiving element; An optical pickup device having an objective lens for condensing the light on an optical recording medium, between the composite optical element and the objective lens, diffracts the forward light beam, the forward zero-order light, and either the plus or minus one. Only the two patterns of the forward path primary light are used, and the forward path 0th order light and the forward path primary light are (m + 1/2) with respect to the track of the optical recording medium on which the forward path light beam is condensed via the objective lens.
A blaze diffraction grating that shifts the track is provided (where m is an integer), and the second light receiving element includes at least a first light receiving unit, a second light receiving unit, a third light receiving unit, and a fourth light receiving unit divided into four. It has a light receiving unit, and can combine (0-order, 0-order), (0-order, 1-order) combinations of (diffracted light of the forward light beam and diffracted light of the return light beam).
(Next order, 0th order), the (0th order, 0th order) light is received by the first light receiving unit and the second light receiving unit to generate a first difference signal, The third order light and the fourth order light are received by the third light receiving unit and the fourth light receiving unit to generate a second difference signal. A tracking error signal is detected based on a difference signal between the difference signal and a constant multiple of the difference signal.
【００１３】請求項７の発明の光記録再生装置では、少
なくとも半導体基板上に形成された第一の受光素子及び
第二の受光素子と、半導体基板上に形成され、半導体基
板とほぼ垂直な発光面を有する半導体レーザと、第一の
受光素子及び第二の受光素子上に固着されるとともに、
半導体レーザの発光面から出射された往路光ビームを反
射し、反射されて戻る復路光ビームを第一の受光素子に
導く半透過反射面と、第一の受光素子上面で反射された
復路光ビームを反射して第二の受光素子に導く高反射面
とが形成されたビームスプリッタとを有する複合光学素
子と、往路光ビームを光記録媒体に集光する対物レンズ
とを有する光学ピックアップ装置と、光学ピックアップ
装置をトラッキング方向に制御駆動する移動手段とを有
する光記録再生装置において、複合光学素子と前記対物
レンズとの間に、往路光ビームを回折して往路０次光
と、プラス、マイナスの何れか一方の往路１次光との二
パターンのみにするとともに、往路光ビームが対物レン
ズを介して集光される光記録媒体のトラックに対して往
路０次光と往路１次光とを（ｍ＋１／２）トラックずら
すブレーズ回折格子を配設し（但し、ｍは整数）、第二
の受光素子は、少なくとも四分割された第一の受光部、
第二の受光部、第三の受光部及び第四の受光部を有し、
（往路光ビームの回折光，復路光ビームの回折光）の組
み合わせを（０次，０次）、（０次，１次）、（１次，
０次）とするとき、（０次，０次）の光を第一の受光部
と第二の受光部とに受光させて第一の差信号を生成し、
（０次，１次）及び（１次，０次）の光を第三の受光部
と第四の受光部とに受光させて第二の差信号を生成し、
第一の差信号と第二の差信号の定数倍との差信号に基づ
いてトラッキングエラー信号を検出するように構成した
ことを特徴とする。なお、ここで言う光記録再生装置
は、再生のみを行う再生専用装置、記録のみを行う記録
専用装置、記録再生の両方を行うことができる装置を含
むものである。In an optical recording / reproducing apparatus according to a seventh aspect of the present invention, at least a first light receiving element and a second light receiving element formed on a semiconductor substrate, and a light emitting element formed on the semiconductor substrate and substantially perpendicular to the semiconductor substrate. A semiconductor laser having a surface, and fixed on the first light receiving element and the second light receiving element,
A semi-transmissive reflection surface that reflects the outward light beam emitted from the light emitting surface of the semiconductor laser and guides the returning optical beam reflected back to the first light receiving element, and a return light beam reflected by the upper surface of the first light receiving element A composite optical element having a beam splitter formed with a high reflection surface that guides the light to the second light receiving element, and an optical pickup device having an objective lens that focuses the outward light beam on the optical recording medium, In an optical recording / reproducing apparatus having a moving means for controlling and driving an optical pickup device in a tracking direction, a forward optical beam is diffracted between a composite optical element and the objective lens, and a forward zero-order light, plus or minus. Only one of the two patterns of the outgoing path primary light is used, and the outgoing path 0th order light and the outgoing primary light are moved with respect to the track of the optical recording medium on which the outgoing light beam is condensed via the objective lens. Preparative (m + 1/2) is arranged a blazed diffraction grating to shift track (where, m is an integer), the second light receiving element, the first light receiving portion that is at least quartered,
Having a second light receiving section, a third light receiving section and a fourth light receiving section,
The combination of (the diffracted light of the forward light beam and the diffracted light of the return light beam) is (0th order, 0th order), (0th order, 1st order), (1st order, 1st order,
(0th order), (0th order, 0th order) light is received by the first light receiving unit and the second light receiving unit to generate a first difference signal,
(0th order, 1st order) and (1st order, 0th order) light are received by a third light receiving portion and a fourth light receiving portion to generate a second difference signal,
A tracking error signal is detected based on a difference signal between the first difference signal and a constant multiple of the second difference signal. Note that the optical recording / reproducing apparatus referred to here includes a reproduction-only apparatus that performs only reproduction, a recording-only apparatus that performs only recording, and an apparatus that can perform both recording and reproduction.
【００１４】そして、上記した請求項３の発明の複合光
学素子、請求項５の発明の光学ピックアップ装置及び請
求項７の発明の光記録再生装置における望まし実施態様
は、往路０次光と往路１次光との分離方向が、複合光学
素子における半導体レーザとビームスプリッタとの配置
方向とほぼ平行とするものである。The preferred embodiments of the composite optical element according to the third aspect of the present invention, the optical pickup device according to the fifth aspect of the invention, and the optical recording / reproducing apparatus according to the seventh aspect of the present invention are the following: The direction of separation from the primary light is substantially parallel to the arrangement direction of the semiconductor laser and the beam splitter in the composite optical element.
【００１５】請求項１の発明のトラッキングエラー信号
検出方法によれば、（０次，０次）の光を受光する第一
の受光部と第二の受光部とで生成される第一の差信号の
オフセットと、（０次，１次）及び（１次，０次）の光
を受光する第三の受光部と第四の受光部とで生成される
第二の差信号のオフセットとが同方向となるので、第一
の差信号と第二の差信号の定数倍との差信号によりオフ
セットのみをキャンセルすることができる。従って、光
記録媒体の種類に影響されない高信頼性を有するトラッ
キングエラー信号検出法とすることができる。According to the tracking error signal detecting method of the first aspect of the present invention, the first difference generated between the first light receiving portion and the second light receiving portion for receiving the (0th order, 0th order) light. The offset of the signal and the offset of the second difference signal generated by the third light-receiving unit and the fourth light-receiving unit that receive the (0th, 1st) and (1st, 0th) light, respectively. Since the directions are the same, only the offset can be canceled by the difference signal between the first difference signal and the constant multiple of the second difference signal. Therefore, a tracking error signal detection method having high reliability not affected by the type of the optical recording medium can be provided.
【００１６】また、上記した請求項１または２の発明の
トラッキングエラー信号検出法を用いた請求項３の発明
の複合光学素子では、この複合光学素子を構成する半導
体基板にトラッキングエラー信号処理を含めたサーボ信
号処理回路を構成することが可能となる。そして、この
複合光学素子を用いた請求項５の発明の光学ピックアッ
プ装置及び請求項７の発明の光記録再生装置では、小型
薄型化及び高信頼性化を図ることができる。In the composite optical element according to the third aspect of the present invention using the tracking error signal detection method according to the first or second aspect of the present invention, the tracking error signal processing is included in the semiconductor substrate constituting the composite optical element. It is possible to configure a servo signal processing circuit. The optical pickup device according to the fifth aspect of the present invention and the optical recording / reproducing device according to the seventh aspect of the present invention using this composite optical element can be made smaller, thinner and more reliable.
【００１７】[0017]
【発明の実施の形態】以下、本発明を適用した具体的な
光学ピックアップ装置の一例について、図１〜図５を参
照して説明する。なお、図中の構成要素で従来の技術と
同様の構造を成しているものについては、同一の参照符
号を付すものとする。また、本発明を適用した光記録再
生装置は従来の技術において図７を参照して説明した事
例と同様であるので、重複する説明を省略する。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of a specific optical pickup device to which the present invention is applied will be described below with reference to FIGS. Note that components in the figure that have the same structure as the conventional technology are denoted by the same reference numerals. Further, the optical recording / reproducing apparatus to which the present invention is applied is the same as the case described with reference to FIG. 7 in the related art, and a duplicate description will be omitted.
【００１８】図１は、光学ピックアップ装置の概略構成
図である。半導体レーザ２の発光面２ａから出射された
往路光ビーム（図中の一点鎖線）はビームスプリッタ４
の半透過反射面４ａで反射され、ブレーズ回折格子９に
入射する。このブレーズ回折格子９は、往路光ビームを
回折して回折光を往路０次光とプラス、マイナス何れか
一方の往路１次光の二パターンのみにするとともに、二
軸アクチュエータ等のサーボアクチュエータ７に具備さ
れた対物レンズ７ａにより光記録媒体８の信号記録面に
集光される往路０次光と往路１次光とを、図２に示した
ように、（ｍ＋１／２）トラックずらすように構成され
ている（但し、ｍは整数であり、図２では１／２トラッ
クずらした状態を示している）。従って、往路０次光と
往路１次光とを（ｍ＋１／２）トラックずらすことによ
り、トラッキングエラー信号におけるＰｕｓｈ−Ｐｕｌ
ｌ信号の位相は逆相となる。そして、信号記録面で回折
されて反射された復路光ビームは再び対物レンズ７ａと
ブレーズ回折格子９とを透過して半透過反射面４ａから
ビームスプリッタ４内に導かれ、第一の受光素子３ａを
照射する（図中の二点鎖線）。さらに、第一の受光素子
３ａ上面で反射された復路光ビームは高反射面４ｂで反
射され、第二の受光素子３ｂを照射する。この第一の受
光素子３ａ及び第二の受光素子３ｂで光電変化した信号
からフォーカシングエラー信号、トラッキングエラー信
号及びＲＦ信号等が検出される。FIG. 1 is a schematic configuration diagram of an optical pickup device. The outward light beam (dashed line in the drawing) emitted from the light emitting surface 2a of the semiconductor laser 2 is
And is incident on the blaze diffraction grating 9. The blazed diffraction grating 9 diffracts the forward light beam to convert the diffracted light into only two patterns, that is, the forward zero-order light and either the positive or negative one-way primary light, and to the servo actuator 7 such as a biaxial actuator. As shown in FIG. 2, the forward zero-order light and the forward first-order light condensed on the signal recording surface of the optical recording medium 8 by the provided objective lens 7 a are shifted by (m + ／) tracks. (Where m is an integer, and FIG. 2 shows a state shifted by 1/2 track). Therefore, by shifting the forward zero-order light and the forward primary light by (m + ／) tracks, the Push-Pul in the tracking error signal is shifted.
The phase of the 1 signal is reversed. The return light beam diffracted and reflected on the signal recording surface again passes through the objective lens 7a and the blazed diffraction grating 9 and is guided from the semi-transmissive reflection surface 4a into the beam splitter 4, and the first light receiving element 3a (Two-dot chain line in the figure). Further, the return light beam reflected on the upper surface of the first light receiving element 3a is reflected on the high reflection surface 4b and irradiates the second light receiving element 3b. A focusing error signal, a tracking error signal, an RF signal, and the like are detected from the signals photoelectrically changed by the first light receiving element 3a and the second light receiving element 3b.
【００１９】以下、ブレーズ回折格子９で回折される往
路光ビームの回折光と、光記録媒体８の信号記録面で回
折されて反射される復路光ビームの回折光の関係につい
て、概略光路図である図３（ａ）〜（ｄ）を参照して説
明する。ブレーズ回折格子９を透過した往路光ビーム
と、光記録媒体８の信号記録面で回折されて反射され、
再びブレーズ回折格子９を透過して第一の受光素子３ａ
及び第二の受光素子３ｂに照射される復路光ビームとの
（往路光ビームの回折光，復路光ビームの回折光）の組
み合わせは、図３（ａ）に示したような（０次，０
次）、図３（ｂ）に示したような（０次，１次）、図３
（ｃ）に示したような（（１次，０次）及び図示を省略
する（１次，１次）の四パターンになる。そして、図３
（ａ）、図３（ｂ）及び図３（ｃ）を合成すると図３
（ｄ）に示したようになる。例えば、ブレーズ回折格子
９に入射する光に対して回折効率を０次：１次＝９０
％：１０％とすれば、上記した四スポットの割合は（０
次，０次）：（０次，１次）：（１次，０次）：（１
次，１次）＝８１：９：９：１となる。The relationship between the diffracted light of the forward light beam diffracted by the blaze diffraction grating 9 and the diffracted light of the backward light beam diffracted and reflected on the signal recording surface of the optical recording medium 8 will be described below with reference to a schematic optical path diagram. This will be described with reference to FIGS. 3 (a) to 3 (d). The outward light beam transmitted through the blazed diffraction grating 9 is diffracted and reflected by the signal recording surface of the optical recording medium 8,
The light passes through the blazed diffraction grating 9 again and passes through the first light receiving element 3a.
The combination of (the diffracted light of the forward light beam and the diffracted light of the backward light beam) with the return light beam applied to the second light receiving element 3b is as shown in FIG.
3) (0th order, 1st order) as shown in FIG.
The four patterns ((primary, zero-order) and illustration (primary, primary) are omitted as shown in FIG.
3 (a), FIG. 3 (b) and FIG.
The result is as shown in FIG. For example, for light incident on the blazed diffraction grating 9, the diffraction efficiency is set to 0th order: 1st order = 90.
%: 10%, the ratio of the four spots is (0
Next, 0th order): (0th, 1st): (1st, 0th): (1
Next, primary) = 81: 9: 9: 1.
【００２０】通常、往路光ビームと戻りの復路光ビーム
とが回折格子を透過すると±１次光が発生し、（＋１
次，−１次）の光は（０次，０次）の光とほぼ同じ位置
に戻るため、異なるトラックからの情報がクロストーク
として加わる。しかしながら、本発明のようにブレーズ
回折格子９を用いれば、往路光ビーム及び復路光ビーム
が０次光及びプラス、マイナス何れか一方の片側の１次
光のみに回折されるため、（１次，１次）の光は（０
次，１次）、（１次，０次）を挟んで（０次，０次）と
は全く反対側に回折され、戻りの復路光ビームを受光す
る第一の受光素子３ａ及び第二の受光素子３ｂにおいて
はクロストークの要因とならない。このように、（１
次，１次）の光は他の信号への影響を与えることがない
ので、以下省略して述べることとする。ところで、（０
次，１次）、（１次，０次）の光は、半導体レーザ２の
発光面２ｂに有する発光点と供役な位置、即ち複合光学
素子１におけるビームスプリッタ４の高反射面４ｂにお
いて重なるが、復路光ビームが高反射面４ｂで反射され
る前後に第一の受光素子３ａと第二の受光素子３ｂとが
配設されているため、これらが完全に一致して重なるこ
とはない。Normally, when the forward light beam and the return light beam pass through the diffraction grating, ± primary light is generated, and (+1)
Since the (next, -1st) light returns to almost the same position as the (0th, 0th) light, information from different tracks is added as crosstalk. However, if the blazed diffraction grating 9 is used as in the present invention, the forward light beam and the backward light beam are diffracted into only the zero-order light and the primary light on either one of the plus and minus sides. The primary light is (0
The first light receiving element 3a and the second light receiving element 3a which receive the returning return light beam are diffracted to the opposite side to the (0th order, 0th order) across the (first order, 1st order) and (1st order, 0th order). This does not cause crosstalk in the light receiving element 3b. Thus, (1
Since the (primary, primary) light does not affect other signals, it will be omitted below. By the way, (0
The (first-order, first-order) and (first-order, zero-order) light overlap with the light-emitting point of the light-emitting surface 2b of the semiconductor laser 2, ie, at the high reflection surface 4b of the beam splitter 4 in the composite optical element 1. However, since the first light receiving element 3a and the second light receiving element 3b are arranged before and after the return light beam is reflected by the high reflection surface 4b, they do not completely coincide and overlap.
【００２１】図４は、図１におけるＡ方向からみた第一
の受光素子３ａと第二の受光素子３ｂの概略Ａ矢視図で
ある。第一の受光素子３ａの受光部は三分割（中央部
ｂ、ｂを挟んだ両側がａ）されており、第二の受光素子
３ｂの受光部はｅ1 、ｅ2 、ｅ3 、ｅ4 、ｅ5 、ｅ6 、
ｅ7 、ｅ8 に八分割されており、ｅ1 とｅ2 とで第一の
受光部を構成し、ｅ3 とｅ4 とで第二の受光部を構成
し、ｅ5 とｅ6 とで第三の受光部を構成し、ｅ7 とｅ8
とで第四の受光部を構成している。そして、第一の受光
素子３ａにおける（（０次，０次）、（０次，１次）、
（１次，０次）の三つのスポットは重なって照射される
が、第二の受光素子３ｂにおいては（０次，０次）のス
ポットは第一の受光部と第二の受光部とにわたって照射
され、（０次，１次）及び（１次，０次）のスポットは
第三の受光部と第四の受光部にわたって照射される。そ
して、図５に示したように、第一の受光部と第二の受光
部とにわたって照射される（０次，０次）のスポットか
ら（ｅ1 ｅ2 − ｅ3 ｅ4 ）あるいは（（ｅ1 ＋ｅ2 ）
−（ｅ3 ＋ｅ4 ））のＰｕｓｈ−Ｐｕｌｌ信号を検出す
ることができるが、対物レンズ７ａのトラッキング方向
の移動によりオフセットを生じる。一方、第三の受光部
と第四の受光部にわたって照射される（１次，０次）及
び（０次，１次）のスポットから検出されるＰｕｓｈ−
Ｐｕｌｌ信号は同じ方向で変調分の位相が逆となるた
め、あわせて検出したものには変調があらわれず、対物
レンズ７ａのトラッキング方向の移動とともに移動する
光ビームによるＤＣオフセットのみが検出される。そし
て、（ｅ5 ｅ6 − ｅ7 ｅ8 ）あるいは（（ｅ5 ＋
ｅ6 ）−（（ｅ7 ＋ｅ8 ））の信号を検出すれば、（０
次，０次）から検出されるＰｕｓｈ−Ｐｕｌｌ信号のオ
フセットと光量比を除いて全く同じオフセットを有する
信号を得ることができる。従って、上記したブレーズ回
折格子９に入射する光に対して回折効率を０次：１次＝
９０％：１０％として（０次，０次）：（０次，１
次）：（１次，０次）：（１次，１次）＝８１：９：
９：１とした場合におけるＤＣオフセットをキャンセル
する定数倍の係数であるＫｔの値を（８１／（９＋９）
〜８１／４．５）として、トラッキングエラー信号を
（ｅ1 ｅ2 −ｅ3 ｅ4 ）−Ｋｔ（ｅ5 ｅ6 −ｅ7 ｅ8 ）
で検出すれば、ＤＣオフセットのみをキャンセルするこ
とができる。実際には、（０次，０次）と（０次，１
次）及び（１次，０次）との光量比のばらつきや収差等
が考慮されて最適なＫｔ値が決定される。FIG. 4 is a schematic view of the first light receiving element 3a and the second light receiving element 3b viewed from the direction A in FIG. Receiving portion of the first light receiving element 3a is divided into three parts (the central part b, both sides of the b is a) are, the light receiving portion of the second light-receiving element 3b is e 1, e 2, e 3 , e 4 , E 5 , e 6 ,
e 7, which is eight divided into e 8, constitutes the first light receiving portion in the e 1 and e 2, constitute a second light receiving portion in the e 3 and e 4, and e 5 and e 6 Constitutes the third light receiving section, and e 7 and e 8
And constitute a fourth light receiving unit. Then, ((0th order, 0th order), (0th order, 1st order),
The three (first-order, zero-order) spots are irradiated in an overlapping manner, but in the second light-receiving element 3b, the (0th-order, zero-order) spot extends over the first light-receiving part and the second light-receiving part. The spots of (0th order, 1st order) and (1st order, 0th order) are irradiated over the third light receiving unit and the fourth light receiving unit. Then, as shown in FIG. 5, (e 1 e 2 −e 3 e 4 ) or (( e 1 + e 2 )
Although the Push-Pull signal of-(e 3 + e 4 )) can be detected, an offset occurs due to the movement of the objective lens 7a in the tracking direction. On the other hand, Push-detected from (first-order, zero-order) and (0-order, first-order) spots irradiated over the third light-receiving unit and the fourth light-receiving unit.
Since the Pull signal has the opposite phase of the modulation in the same direction, no modulation appears in the detected signal, and only the DC offset due to the light beam moving with the movement of the objective lens 7a in the tracking direction is detected. And, (e 5 e 6 - e 7 e 8) or ((e 5 +
When a signal of (e 6 ) − ((e 7 + e 8 )) is detected, (0
It is possible to obtain a signal having exactly the same offset except for the offset of the Push-Pull signal detected from (0th order) and the light amount ratio. Accordingly, the diffraction efficiency of the light incident on the blazed diffraction grating 9 is 0th order: 1st order =
90%: 10% (0th order, 0th order): (0th order, 1st order
Next): (1st, 0th): (1st, 1st) = 81: 9:
When the ratio is 9: 1, the value of Kt which is a constant multiple coefficient for canceling the DC offset is set to (81 / (9 + 9)
８１81 / 4.5), and the tracking error signal is (e 1 e 2 −e 3 e 4 ) −Kt (e 5 e 6 −e 7 e 8 ).
, It is possible to cancel only the DC offset. Actually, (0th order, 0th order) and (0th order, 1st order)
The optimum Kt value is determined in consideration of the variation in the light amount ratio between (next) and (first order, zero order), aberration, and the like.
【００２２】なお、本発明におけるフォーカシングエラ
ー信号は（ａ−ｂ）−（（ｅ1 ＋ｅ4 ＋ｅ5 ＋ｅ8 ）−
（ｅ2 ＋ｅ3 ＋ｅ6 ＋ｅ7 ））により検出することがで
き、ＲＦ信号は（ｅ1 ＋ｅ2 ＋ｅ3 ＋ｅ4 ）で検出する
ことができる。In the present invention, the focusing error signal is (ab)-((e 1 + e 4 + e 5 + e 8 )-.
(E 2 + e 3 + e 6 + e 7 )), and the RF signal can be detected by (e 1 + e 2 + e 3 + e 4 ).
【００２３】[0023]
【発明の効果】本発明のトラッキングエラー信号検出方
法によれば、従来の検出方法と比較して簡略であるとと
もに、異なる種類の光記録媒体であってもオフセットが
生じない。従って、このトラッキングエラー信号検出方
法を用いた複合光学素子では、この複合光学素子を構成
する半導体基板にトラッキングエラー信号処理を含めた
サーボ信号処理回路を構成することが可能となる。そし
て、この複合光学素子を用いた光学ピックアップ装置及
び光記録再生装置では、小型薄型化及び高信頼性化を図
ることができる。According to the tracking error signal detecting method of the present invention, the method is simpler than that of the conventional detecting method, and no offset occurs even if the optical recording medium is of a different type. Therefore, in the composite optical element using the tracking error signal detection method, it is possible to configure a servo signal processing circuit including the tracking error signal processing on the semiconductor substrate forming the composite optical element. In the optical pickup device and the optical recording / reproducing device using the composite optical element, it is possible to reduce the size and thickness and improve the reliability.
【図１】 本発明の光学ピックアップ装置の概略構成図
である。FIG. 1 is a schematic configuration diagram of an optical pickup device of the present invention.
【図２】 本発明の往路０次光と往路１次光の光記録媒
体信号記録面における概略状態図である。FIG. 2 is a schematic diagram showing the state of the zero-order light and the first-order light on the optical recording medium signal recording surface according to the present invention;
【図３】 （ａ）〜（ｄ）は、本発明のブレーズ回折格
子で回折される往路光ビームの回折パターンと、光記録
媒体で反射される復路光ビームの回折パターンとの関係
を説明する概略光路図である。FIGS. 3A to 3D illustrate a relationship between a diffraction pattern of a forward light beam diffracted by a blazed diffraction grating of the present invention and a diffraction pattern of a backward light beam reflected by an optical recording medium. It is a schematic optical path diagram.
【図４】 図１におけるＡ方向からみた第一の受光素子
及び第二の受光素子の概略Ａ矢視図である。FIG. 4 is a schematic view of a first light receiving element and a second light receiving element as viewed from a direction A in FIG.
【図５】 本発明のトラッキングエラー信号検出方法に
おいて、オフセットがキャンセルされる状態を説明する
概略説明図である。FIG. 5 is a schematic diagram illustrating a state in which an offset is canceled in the tracking error signal detection method of the present invention.
【図６】 従来の光学ピックアップ装置の概略構成図で
ある。FIG. 6 is a schematic configuration diagram of a conventional optical pickup device.
【図７】 光記録再生装置の概略構成図である。FIG. 7 is a schematic configuration diagram of an optical recording / reproducing apparatus.
【図８】 図６におけるＢ方向からみた第一の受光素子
及び第二の受光素子の概略Ｂ矢視図である。8 is a schematic B arrow view of a first light receiving element and a second light receiving element as viewed from a direction B in FIG. 6;
１…複合光学素子、２…半導体レーザ、２ａ…発光面、
３ａ…第一の受光素子、３ｂ…第二の受光素子、４…ビ
ームスプリッタ、４ａ…半透過反射面、４ｂ…高反射
面、５…半導体基板、６…スペーサ、７…サーボアクチ
ュエータ、７ａ…対物レンズ、７ｂ…可動部、７ｃ…平
行バネ、７ｄ…固定部、８…光記録媒体、９…ブレーズ
回折格子、１０ａ…メインガイド軸、１０ｂ…サブガイ
ド軸、１１…マグネット、１２…外ヨーク、１３…内ヨ
ーク、１４…コイル、１５…光学ブロックDESCRIPTION OF SYMBOLS 1 ... Composite optical element, 2 ... Semiconductor laser, 2a ... Light emitting surface,
3a: first light receiving element, 3b: second light receiving element, 4: beam splitter, 4a: semi-transmissive reflecting surface, 4b: high reflecting surface, 5: semiconductor substrate, 6: spacer, 7: servo actuator, 7a ... Objective lens, 7b: movable part, 7c: parallel spring, 7d: fixed part, 8: optical recording medium, 9: blaze diffraction grating, 10a: main guide shaft, 10b: sub guide shaft, 11: magnet, 12: outer yoke , 13 ... inner yoke, 14 ... coil, 15 ... optical block
Claims (8)
路光ビームを受光素子に受光してトラッキングエラー信
号を検出するトラッキングエラー信号検出方法におい
て、 前記往路光ビームをブレーズ回折格子で回折して往路０
次光と、プラス、マイナスの何れか一方の往路１次光と
の二パターンのみにし、 前記復路光ビームの復路０次光のＰｕｓｈ−Ｐｕｌｌ信
号と、前記復路光ビームの復路１次光のＰｕｓｈ−Ｐｕ
ｌｌ信号との差信号に基づいてトラッキングエラー信号
を検出することを特徴とするトラッキングエラー信号検
出方法。1. A tracking error signal for focusing a forward light beam on an optical recording medium, receiving a return light beam that is diffracted by the optical recording medium and returning to a light receiving element, and detecting a tracking error signal. In the detection method, the outgoing light beam is diffracted by a blaze diffraction grating, and
A Push-Pull signal of the return 0 beam of the return light beam, and a Push-Pull signal of the return 0 light of the return light beam. -Pu
A tracking error signal detection method, wherein a tracking error signal is detected based on a difference signal from the ll signal.
往路０次光と前記往路１次光とを（ｍ＋１／２）トラッ
クずらし（但し、ｍは整数）、 前記受光素子は、少なくとも四分割された第一の受光
部、第二の受光部、第三の受光部及び第四の受光部を有
し、 （前記往路光ビームの回折光，前記復路光ビームの回折
光）の組み合わせを（（０次，０次）、（０次，１
次）、（１次，０次）とするとき、 前記（０次，０次）を前記第一の受光部と前記第二の受
光部とに受光させて第一の差信号を生成し、 前記（０次，１次）及び前記（１次，０次）を前記第三
の受光部と前記第四の受光部とに受光させて第二の差信
号を生成し、 前記第一の差信号と前記第二の差信号の定数倍との差信
号に基づいてトラッキングエラー信号を検出することを
特徴とする請求項１に記載のトラッキングエラー信号検
出方法。2. A method according to claim 1, wherein the 0th-order light on the outward path and the 1st-order light on the outward path are shifted by (m + 1/2) tracks (where m is an integer) with respect to the track of the optical recording medium. A first light receiving unit, a second light receiving unit, a third light receiving unit, and a fourth light receiving unit. The combination of (the diffracted light of the outward light beam and the diffracted light of the return light beam) is represented by ( (0 order, 0 order), (0 order, 1
Next) and (1st, 0th), the (0th, 0th) is received by the first light receiving unit and the second light receiving unit to generate a first difference signal, The (0th order, 1st order) and the (1st order, 0th order) are received by the third light receiving unit and the fourth light receiving unit to generate a second difference signal, and the first difference The tracking error signal detecting method according to claim 1, wherein the tracking error signal is detected based on a difference signal between the signal and a constant multiple of the second difference signal.
一の受光素子及び第二の受光素子と、 前記半導体基板上に形成され、前記半導体基板とほぼ垂
直な発光面を有する半導体レーザと、 前記第一の受光素子及び前記第二の受光素子上に固着さ
れるとともに、前記発光面から出射された往路光ビーム
を反射し、反射されて戻る復路光ビームを前記第一の受
光素子に導く半透過反射面と、 前記第一の受光素子上面で反射された前記復路光ビーム
を反射して前記第二の受光素子に導く高反射面とが形成
されたビームスプリッタとを有する複合光学素子におい
て、 前記往路光ビームを回折して往路０次光と、プラス、マ
イナスの何れか一方の往路１次光との二パターンのみに
するとともに、前記往路光ビームが対物レンズを介して
集光される光記録媒体のトラックに対して前記往路０次
光と前記往路１次光とを（ｍ＋１／２）トラックずらす
ブレーズ回折格子を前記半透過反射面と前記対物レンズ
との間に配設し（但し、ｍは整数）、 前記第二の受光素子は、少なくとも四分割された第一の
受光部、第二の受光部、第三の受光部及び第四の受光部
を有し、 （前記往路光ビームの回折光，前記復路光ビームの回折
光）の組み合わせを（（０次，０次）、（０次，１
次）、（１次，０次）とするとき、 前記（０次，０次）を前記第一の受光部と前記第二の受
光部とに受光させて第一の差信号を生成し、 前記（０次，１次）及び前記（１次，０次）を前記第三
の受光部と前記第四の受光部とに受光させて第二の差信
号を生成し、 前記第一の差信号と前記第二の差信号の定数倍との差信
号に基づいてトラッキングエラー信号を検出するように
構成したことを特徴とする複合光学素子。A first light receiving element and a second light receiving element formed on at least a semiconductor substrate; a semiconductor laser formed on the semiconductor substrate and having a light emitting surface substantially perpendicular to the semiconductor substrate; A half light beam fixed to the first light receiving element and the second light receiving element, reflects the outward light beam emitted from the light emitting surface, and guides the reflected return light beam to the first light receiving element. In a composite optical element having a transmission / reflection surface and a beam splitter formed with a high reflection surface that reflects the return light beam reflected by the upper surface of the first light receiving element and guides the reflected light beam to the second light receiving element, The forward light beam is diffracted into only two patterns, that is, the 0th-order light in the forward path and the positive or negative primary light in one of the positive and negative directions, and the light in which the forward light beam is condensed via the objective lens. Record A blaze diffraction grating for shifting the 0th-order light on the outward path and the 1st-order light on the outward path by (m + 1/2) tracks with respect to the track of the medium is provided between the semi-transmissive reflection surface and the objective lens (where m Is an integer), the second light receiving element has a first light receiving unit, a second light receiving unit, a third light receiving unit and a fourth light receiving unit divided at least into four, The combination of the diffracted light and the diffracted light of the return light beam is represented by ((0th order, 0th order), (0th order, 1st order)
Next) and (1st, 0th), the (0th, 0th) is received by the first light receiving unit and the second light receiving unit to generate a first difference signal, The (0th order, 1st order) and the (1st order, 0th order) are received by the third light receiving unit and the fourth light receiving unit to generate a second difference signal, and the first difference A composite optical element configured to detect a tracking error signal based on a difference signal between a signal and a constant multiple of the second difference signal.
離方向が、 前記半導体レーザと前記ビームスプリッタとの配置方向
とほぼ平行であることを特徴とする請求項３に記載の複
合光学素子。4. The composite according to claim 3, wherein a separation direction of the outgoing zero-order light and the outgoing primary light is substantially parallel to an arrangement direction of the semiconductor laser and the beam splitter. Optical element.
一の受光素子及び第二の受光素子と、 前記半導体基板上に形成され、前記半導体基板とほぼ垂
直な発光面を有する半導体レーザと、 前記第一の受光素子及び前記第二の受光素子上に固着さ
れるとともに、前記発光面から出射された往路光ビーム
を反射し、反射されて戻る復路光ビームを前記第一の受
光素子に導く半透過反射面と、 前記第一の受光素子で反射された前記復路光ビームを反
射して前記第二の受光素子に導く高反射面とが形成され
たビームスプリッタとを有する複合光学素子と、 前記往路光ビームを光記録媒体に集光する対物レンズと
を有する光学ピックアップ装置において、 前記複合光学素子と前記対物レンズとの間に、 前記往路光ビームを回折して往路０次光と、プラス、マ
イナスの何れか一方の往路１次光との二パターンのみに
するとともに、前記往路光ビームが対物レンズを介して
集光される光記録媒体のトラックに対して前記往路０次
光と前記往路１次光とを（ｍ＋１／２）トラックずらす
ブレーズ回折格子を配設し（但し、ｍは整数）、 前記第二の受光素子は、少なくとも四分割された第一の
受光部、第二の受光部、第三の受光部及び第四の受光部
を有し、 （前記往路光ビームの回折光，前記復路光ビームの回折
光）の組み合わせを（（０次，０次）、（０次，１
次）、（１次，０次）とするとき、 前記（０次，０次）を前記第一の受光部と前記第二の受
光部とに受光させて第一の差信号を生成し、 前記（０次，１次）及び前記（１次，０次）を前記第三
の受光部と前記第四の受光部とに受光させて第二の差信
号を生成し、 前記第一の差信号と前記第二の差信号の定数倍との差信
号に基づいてトラッキングエラー信号を検出するように
構成したことを特徴とする光学ピックアップ装置。5. A semiconductor laser formed on at least a semiconductor substrate and having a light emitting surface substantially perpendicular to the semiconductor substrate, wherein the first and second light receiving elements are formed on at least a semiconductor substrate; A half light beam fixed to the first light receiving element and the second light receiving element, reflects the outward light beam emitted from the light emitting surface, and guides the reflected return light beam to the first light receiving element. A composite optical element comprising: a transmission / reflection surface; and a beam splitter formed with a high reflection surface that reflects the return light beam reflected by the first light receiving element and guides the reflected light beam to the second light receiving element. An optical pickup device having an objective lens for converging a forward light beam on an optical recording medium, wherein between the composite optical element and the objective lens, the forward light beam is diffracted by forward zero-order light, and And the forward zero-order light and the forward zero-order light with respect to the track of the optical recording medium on which the forward light beam is condensed via the objective lens. A blaze diffraction grating for shifting the forward-order primary light by (m + 1/2) tracks is provided (where m is an integer). The second light-receiving element includes at least a first light-receiving portion divided into at least four parts, and a second light-receiving portion. A light receiving section, a third light receiving section, and a fourth light receiving section, wherein a combination of (the diffracted light of the forward light beam and the diffracted light of the return light beam) is ((0th order, 0th order), (0th order) , 1
Next) and (1st, 0th), the (0th, 0th) is received by the first light receiving unit and the second light receiving unit to generate a first difference signal, The (0th order, 1st order) and the (1st order, 0th order) are received by the third light receiving unit and the fourth light receiving unit to generate a second difference signal, and the first difference An optical pickup device configured to detect a tracking error signal based on a difference signal between a signal and a constant multiple of the second difference signal.
離方向が、 前記半導体レーザと前記ビームスプリッタとの配置方向
とほぼ平行であることを特徴とする請求項５に記載の光
学ピックアップ装置。6. The optical device according to claim 5, wherein a separation direction of the outgoing zero-order light and the outgoing primary light is substantially parallel to an arrangement direction of the semiconductor laser and the beam splitter. Pickup device.
一の受光素子及び第二の受光素子と、 前記半導体基板上に形成され、前記半導体基板とほぼ垂
直な発光面を有する半導体レーザと、 前記第一の受光素子及び前記第二の受光素子上に固着さ
れるとともに、前記発光面から出射された往路光ビーム
を反射し、反射されて戻る復路光ビームを前記第一の受
光素子に導く半透過反射面と、 前記第一の受光素子で反射された前記復路光ビームを反
射して前記第二の受光素子に導く高反射面とが形成され
たビームスプリッタとを有する複合光学素子と、 前記往路光ビームを光記録媒体に集光する対物レンズと
を有する光学ピックアップ装置と、 前記光学ピックアップ装置をトラッキング方向に制御駆
動する移動手段とを有する光記録再生装置において、 前記複合光学素子と前記対物レンズとの間に、 前記往路光ビームを回折して往路０次光と、プラス、マ
イナスの何れか一方の往路１次光との二パターンのみに
するとともに、前記往路光ビームが対物レンズを介して
集光される光記録媒体のトラックに対して前記往路０次
光と前記往路１次光とを（ｍ＋１／２）トラックずらす
ブレーズ回折格子を配設し（但し、ｍは整数）、 前記第二の受光素子は、少なくとも四分割された第一の
受光部、第二の受光部、第三の受光部及び第四の受光部
を有し、 （前記往路光ビームの回折光，前記復路光ビームの回折
光）の組み合わせを（（０次，０次）、（０次，１
次）、（１次，０次）とするとき、 前記（０次，０次）を前記第一の受光部と前記第二の受
光部とに受光させて第一の差信号を生成し、 前記（０次，１次）及び前記（１次，０次）を前記第三
の受光部と前記第四の受光部とに受光させて第二の差信
号を生成し、 前記第一の差信号と前記第二の差信号の定数倍との差信
号に基づいてトラッキングエラー信号を検出するように
構成したことを特徴とする光記録再生装置。7. a semiconductor laser having at least a first light receiving element and a second light receiving element formed on a semiconductor substrate, a semiconductor laser formed on the semiconductor substrate, and having a light emitting surface substantially perpendicular to the semiconductor substrate; A half light beam fixed to the first light receiving element and the second light receiving element, reflects the outward light beam emitted from the light emitting surface, and guides the reflected return light beam to the first light receiving element. A composite optical element comprising: a transmission / reflection surface; and a beam splitter formed with a high reflection surface that reflects the return light beam reflected by the first light receiving element and guides the reflected light beam to the second light receiving element. An optical recording / reproducing apparatus having an optical pickup device having an objective lens for condensing a forward light beam on an optical recording medium, and moving means for controlling and driving the optical pickup device in a tracking direction. Between the composite optical element and the objective lens, diffracting the forward light beam to form only two patterns of forward zero-order light and either positive or negative one-way primary light; A blaze diffraction grating for displacing the 0th-order light on the outward path and the 1st-order light on the outward path by (m + 1/2) tracks with respect to the track of the optical recording medium on which the outward light beam is condensed via the objective lens is disposed ( (Where m is an integer), the second light receiving element has at least a first light receiving unit, a second light receiving unit, a third light receiving unit, and a fourth light receiving unit divided into four, The combination of the diffracted light of the light beam and the diffracted light of the return light beam is ((0th order, 0th order), (0th order, 1st order)
Next) and (1st, 0th), the (0th, 0th) is received by the first light receiving unit and the second light receiving unit to generate a first difference signal, The (0th order, 1st order) and the (1st order, 0th order) are received by the third light receiving unit and the fourth light receiving unit to generate a second difference signal, and the first difference An optical recording / reproducing apparatus configured to detect a tracking error signal based on a difference signal between a signal and a constant multiple of the second difference signal.
離方向が、 前記半導体レーザと前記ビームスプリッタとの配置方向
とほぼ平行であることを特徴とする請求項７に記載の光
記録再生装置。8. The light according to claim 7, wherein the direction of separation between the outgoing zero-order light and the outgoing primary light is substantially parallel to the arrangement direction of the semiconductor laser and the beam splitter. Recording and playback device.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9206625A JPH1153748A (en) | 1997-07-31 | 1997-07-31 | Tracking error signal detecting method, composite optical element using the method, optical pickup device using the element and optical recording/reproducing device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9206625A JPH1153748A (en) | 1997-07-31 | 1997-07-31 | Tracking error signal detecting method, composite optical element using the method, optical pickup device using the element and optical recording/reproducing device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH1153748A true JPH1153748A (en) | 1999-02-26 |
Family
ID=16526478
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP9206625A Pending JPH1153748A (en) | 1997-07-31 | 1997-07-31 | Tracking error signal detecting method, composite optical element using the method, optical pickup device using the element and optical recording/reproducing device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH1153748A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6819637B1 (en) | 1999-12-14 | 2004-11-16 | Fujitsu Limited | Magneto-optical apparatus and optical head |
-
1997
- 1997-07-31 JP JP9206625A patent/JPH1153748A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6819637B1 (en) | 1999-12-14 | 2004-11-16 | Fujitsu Limited | Magneto-optical apparatus and optical head |
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