JPS6083229A - Automatic focus adjusting device for optical disk head - Google Patents
Automatic focus adjusting device for optical disk headInfo
- Publication number
- JPS6083229A JPS6083229A JP58191280A JP19128083A JPS6083229A JP S6083229 A JPS6083229 A JP S6083229A JP 58191280 A JP58191280 A JP 58191280A JP 19128083 A JP19128083 A JP 19128083A JP S6083229 A JPS6083229 A JP S6083229A
- Authority
- JP
- Japan
- Prior art keywords
- photodetector
- light
- reflected light
- optical
- focus
- 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.)
- Granted
Links
Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
- G11B7/13—Optical detectors therefor
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/08—Disposition or mounting of heads or light sources relatively to record carriers
- G11B7/09—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
- G11B7/0908—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following for focusing only
- G11B7/0909—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following for focusing only by astigmatic methods
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/08—Disposition or mounting of heads or light sources relatively to record carriers
- G11B7/09—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
- G11B7/094—Methods and circuits for servo offset compensation
Landscapes
- Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Automatic Focus Adjustment (AREA)
- Optical Recording Or Reproduction (AREA)
Abstract
Description
【発明の詳細な説明】
〔発明の技術分野〕
この発明は、デジタルオーテイオディスク、ビデオディ
スク、コンピュータの光ティスフ等の１ａ報記録媒体か
ら情報を胱出し或はストき込む光ティスフヘッドの自動
焦点調節装置Ｆ特に非点収差光学系を用いた自動焦点調
節装置に関する。Detailed Description of the Invention [Technical Field of the Invention] This invention relates to automatic focusing of an optical disc head that extracts or inputs information from a 1a information recording medium such as a digital audio disc, a video disc, or an optical disc for a computer. The present invention relates to an adjustment device F, particularly an automatic focus adjustment device using an astigmatism optical system.
近年情報記録盤上に光学的に記録きれた情報をンーザ光
を用いたヘッドで杓生じたり、逆に情報を記録する。光
ビデオディスク装置、光オーディオディスク装＃等の開
発が盛んである。この細光テイスク装置のヘッド（以下
光ディスクヘッドと称す）では、情報の正確な記録再生
の為に、集束ンーザ光を情報記録媒体であるディスクの
情報記録トラック上に常に正しく焦点合わせをして照射
する為の自動焦点調節装置が必要でおる。このような自
動焦点装置として、非点収差光学系を用いて情報検出及
び焦点位餉検出を行なう方式が知られている。第１図は
この従来の非点収差光学系を使用した光デイスクヘッド
の自動焦点調節装置を概略的に示す光路図、第２図はそ
の光検知器以下のサーボ機構を示す概略図である。図に
おいて（ＩＩは半導体レーザ等の光源、（２）は光源（
１）より出射された出射光束、（３）は対物レンズ、（
４）は対物レンズの合焦点位置付近に國かれたディジタ
ルオーディオ信号、ピテオ信号等の情＋１．豪がトラッ
ク状（／Ｃ記録されている情報記録媒体である光テイヌ
ク。＋５１４’；ｊディスク（４）上の集光スポットＧ
つから対物レンズ（３）をへての反射光束、（６）は出
射光束を分離するビームスプリッタ、（７）は反別光束
ｆ５１ ＶＬ非非点収音与える光学素子である円筒レン
ズでその円筒軸方向をＸ（紙面に直角）、これにレンス
面内で直交する方向をｙとする。（８）はＸ＋ ７方向
と４５° の角度をもつ分割線で（８ａ）（８ｂ’）（
８ａＭ８ｄ） に４分割き（Ｖ
れた光検知器、（９）はそれへ投Ｗ」芒ねる反射光束（
もによる合焦時の反射光スポット、（９Ｘ、）はディス
ク（４）が合焦点位置より近すいた時の、（９ｙ）Ｌｄ
−、遠ざかった時の反射光スボツ）、（Ｉｌｌは加模−
器（１１１０２１及び差動増幅器０３＋よりなる焦点付
１１′Ｉ検出回路１１４）ｉｉ加算器からなる情報検出
回路、 （１５１は対物レンズを光軸方向に移動させる
フォーカスアクチェータ。In recent years, information that has been optically recorded on an information recording disk can be scooped out using a head using laser light, or conversely, information can be recorded. Optical video disc devices, optical audio disc devices, etc. are being actively developed. In order to accurately record and reproduce information, the head of this narrow optical disk device (hereinafter referred to as an optical disk head) always correctly focuses and irradiates the focused laser beam onto the information recording track of the disk, which is the information recording medium. An automatic focus adjustment device is required for this purpose. As such an automatic focusing device, a method is known that uses an astigmatism optical system to detect information and focus position. FIG. 1 is an optical path diagram schematically showing an automatic focusing device for an optical disk head using this conventional astigmatism optical system, and FIG. 2 is a schematic diagram showing a servo mechanism below the photodetector. In the figure, (II is a light source such as a semiconductor laser, (2) is a light source (
1) is the output light beam emitted from, (3) is the objective lens, (
4) Information on digital audio signals, piteo signals, etc. that are transmitted near the focal point position of the objective lens +1. Australia is a track-shaped (/C) optical recording medium which is recorded.+514';j Focused spot G on disk (4)
The reflected light flux passes through the objective lens (3), (6) is a beam splitter that separates the emitted light flux, and (7) is a cylindrical lens that is an optical element that provides a separate light flux f51 VL astigmatic sound collection. Let the axial direction be X (perpendicular to the plane of the paper), and the direction perpendicular to this in the lens plane be y. (8) is a dividing line that makes an angle of 45° with the X+7 direction, (8a) (8b') (
8aM8d) The photodetector is divided into four parts (V), and (9) is the reflected light beam that is projected onto it (W).
The reflected light spot (9X,) when the disc (4) is in focus is the (9y) Ld when the disc (4) is closer than the in-focus position.
-, reflected light when moving away), (Ill is Kamo-
(111021 and a focusing actuator 114 consisting of a differential amplifier 03+); ii an information detection circuit consisting of an adder; (151 is a focus actuator that moves the objective lens in the optical axis direction);
（Ｉ６）はフォーカスアクチェータ欽））をμｍ」勢し
対物レンズを駆動するＶンズ駆動回路、０力は図示され
ていない情報検出回路である。(I6) is a V-lens drive circuit that forces the focus actuator by .mu.m to drive the objective lens, and 0 power is an information detection circuit (not shown).
次にその動作を説明する。光７＃ｔｌｌよシ出射したレ
ーザ出射光束（２）は対物レンズ（３）により収束され
。Next, its operation will be explained. The laser beam (2) emitted from the light 7#tll is converged by the objective lens (3).
ディスク（４）のトラック上に集光スポット（２）を形
成する。この集光スボツ）［＋からのディスク（４）上
の情報トラックから読出された情報を含む反身９光束（
５）はビームスプリッタ（６）で出射光束（２）と分離
され。A focused spot (2) is formed on a track of a disk (4). This condensing slot) [+ contains nine beams of light (
5) is separated from the output beam (2) by a beam splitter (6).
円筒レンズ（７）によって一方向だけより収求される非
点収差光束に変換される。ｆｆ１ｌち円筒レンズ（７）
のＸと直交するＸ方向と光軸を含む平面（紙面）内では
円筒レンズ（７）の収束作用によシ点Ｑに集光する。従
って非点収差を受けた反射光束の光分布形状は０点Ｑに
おいてＸ方向に長い線状、ＰＡにおいてＹ方向に長い線
状、その間六ｎｘ ＋ ｙの倒れかの方向を長径とする
長円形か円形となる。ディスク（４）が対物レンズ（３
）の合焦点位置にある時（以下合焦時と称す）に非点収
差を受けた反射光束の元分布形状が円形となる位置に４
分割光検知器（８）が置かれている。従って、光検知器
１８１に１合焦時には円形の反別光スポット１９１が、
光ディスク（４）が合焦時よす対物し／ズ（３＋ＶＣ近
すく方向に変位するとＸ方向に細長い長円形の反射光ス
ホツ）（９Ｘ’）が合焦時より遠さかる方向に変位うる
とＸ方向に細長い長円形の反オＪ光スボツ１−（９ｙ）
が入Ｍ、Ｊされる。そして円形反射光スポット（９）の
１晴の谷受光頭載（ｓａ）（ａｂ）（ｓｃ）（ａａ）
による受光面ｈ＋ ＩｉＪニーｉｊｉシく。The cylindrical lens (7) converts the light into an astigmatic light beam that is focused in only one direction. ff1l cylindrical lens (7)
In a plane (plane of paper) including the optical axis and the X direction perpendicular to Therefore, the light distribution shape of the reflected light beam subjected to astigmatism is a long line in the X direction at the 0 point Q, a long line in the Y direction at the PA, and an ellipse whose major axis is in the direction of the inclination of 6nx + y. It becomes circular. The disk (4) is the objective lens (3
) at the in-focus position (hereinafter referred to as "in-focus"), the original distribution shape of the reflected light beam that has undergone astigmatism is circular.
A split photodetector (8) is placed. Therefore, when one focus is on the photodetector 181, a circular anti-separate light spot 191 is created.
When the optical disc (4) is in focus, the objective lens (3+VC) (if it is displaced in the near direction, it will reflect an elongated oval light beam in the X direction) (9X') can be displaced in the direction further away than when it is in focus. Oval J-optical socket 1-(9y), elongated in the X direction
is entered M and J. Then, the circular reflected light spot (9) receives a clear trough (sa) (ab) (sc) (aa)
The light-receiving surface h+ IiJ knee iji shiku.
長径がＸ方向の反射光スポット（９ｘ）の時は受光領域
（８ａ）（８ｃ）が、長径がＸ方向の反射ｔＹスホツ）
（９ｙ）の時は、受光領域（８ｂ）（８ｄ）が、他の頭
載、より受光面積が犬となる。よって受光領域（８ａ）
（８ｃ）の受光出力和をとる加算器（１１）の出力と、
・受光領域（８ｂ）（８ｄ）の受光出力第１」をとる加
９−器（１２１の出力との差を差動増幅器（Ｉ３）より
取出せｄ′、その１１１力佃号、即ち焦点付ＩＰ７検出
回路（１ｍの出カイ７）号Ｊｉｆは１合焦時で円形の反
射光スポット（９）の時は岑。When the major axis is the reflected light spot (9x) in the X direction, the light receiving area (8a) (8c) is the reflected light spot (9x) whose major axis is in the X direction.
At the time of (9y), the light-receiving areas (8b) and (8d) have a larger light-receiving area than those on other heads. Therefore, the light receiving area (8a)
(8c) The output of the adder (11) that calculates the sum of the received light outputs,
・The difference between the output of the adder (121) which takes the light receiving output 1 of the light receiving areas (8b) and (8d) is taken out from the differential amplifier (I3) d', its 111 power d', that is, the focused IP7 The detection circuit (1m output 7) No. Jif is in focus when a circular reflected light spot (9) is detected.
光ディスク（４）が合焦時よシ近ずきＸ方向に１ｌｌｌ
Ｎ長い反射光スポット（９Ｘ）になると正、）゛０ディ
スク（４１が合焦時より遠さかりＸ方向に細長い反射光
スボツ）（９ｙ）になると負ＶＬなり、その合焦点位置
からｑずれに略比例した大きさの出力となる。従つてこ
の焦点付ｍ１ｔ（ｐ出口路α（１）の出力Ｅｆによりレ
ンズ駆動回路α６）を制？ＭＩＬ、、フォーカスアクチ
ェータ０団を付勢させて、対物レンズ（３）を光軸方向
に動かすことによって自動的に焦点合わせが行なわれる
。When the optical disc (4) is in focus, move 1llll towards it in the X direction.
When the reflected light spot becomes N long (9X), it becomes positive, and when it becomes )゛0 disk (41 is a reflected light spot that is farther away than when in focus and is elongated in the X direction) (9y), it becomes negative VL, and it is shifted by q from the focused position The output is approximately proportional in size. Therefore, this focusing m1t (lens drive circuit α6) is controlled by the output Ef of the p exit path α(1)? Focusing is automatically performed by energizing the focus actuator group MIL and moving the objective lens (3) in the optical axis direction.
又１反射光速＋５１に含まれる光ディスク（４）からの
読出し情報は各受光領域による受光出力和をとる情報検
出回路０滲により取出孕れる得失回路面に導かれる。Further, the information read from the optical disk (4) included in the speed of 1 reflected light + 51 is guided to the gain/loss circuit surface where it is extracted by the information detection circuit 0 which calculates the sum of the light reception outputs of the respective light reception areas.
しかし上述の従来装置では実用Ｖｔ−あたって次のよう
な問題点がめった。即ち１合焦時の差動増幅器θ：葵の
出力Ｅｆは零であるが、光検知器（８）への反射光強度
が零というわけではない。受光領域（８ａ）と（８Ｃ）
への入射光強度のオ■と（８ｂ）と（８ｄ）への入射光
強度の和がバランスしているため出力が零となっている
にすきない。この時光検知器（８１面上の反射光束の分
布が何等かの原因で変化すると。However, the above-mentioned conventional device has encountered the following problems when it comes to practical Vt. That is, although the output Ef of the differential amplifier θ: Aoi at the time of one focus is zero, the intensity of the reflected light to the photodetector (8) is not zero. Light receiving area (8a) and (8C)
The output should be zero because the intensity of the incident light on (8b) and the sum of the intensity of the incident light on (8d) are balanced. At this time, if the distribution of the reflected light flux on the photodetector (81 surface) changes for some reason.
上記のバランスがくずれて３合焦点位置が変っていない
のにかかわらずあたかも焦点位置が変化したかのように
差動増幅器０３１に出力が生ずる。これの原因としては
、光源Ｕ＋の発光分布変動がある。The above-mentioned balance is disrupted, and an output is generated in the differential amplifier 031 as if the focal position had changed, even though the three focal points have not changed. The cause of this is a variation in the light emission distribution of the light source U+.
光源（１）が半導体レーザの場合は励起′ｊｔｊ’流の
変化や。When the light source (1) is a semiconductor laser, the excitation 'jtj' flow changes.
経年的な劣化によって発光分布が変化する。光束分布は
中心が最太強婁の単峰の山イ（￥強１髪分布であり、か
つ４分割の中心が光束中心と一致しているため、わずか
な分布の変動もバランスに太きく影幹する。また他の要
因として、アドオンディスク（記録可能ディスク）にお
けるプリグループ（案内トラック）や記録ビットからの
回折光成分の影神がある。これらの回折光のパターン分
布は光軸対称とＶｉ限らず、トラックずれの杵厖や、プ
リグループに信号が記録されているかとうかで変化する
。このため合焦時の円形分布が崩れて走跡臓のオフセッ
トが生ずることになる。The luminescence distribution changes due to deterioration over time. The luminous flux distribution is a single-peaked peak with the center being the thickest and strongest (because it is a single-peak distribution, and the center of the four divisions coincides with the luminous flux center, even slight fluctuations in the distribution will have a large impact on the balance. Another factor is the influence of diffracted light components from pre-groups (guide tracks) and recording bits on add-on discs (recordable discs).The pattern distribution of these diffracted lights is based on optical axis symmetry and Vi However, it changes depending on whether a signal is recorded in the pre-group or not due to track deviation.As a result, the circular distribution at the time of focus is disrupted and an offset occurs in the trace.
〔発明の概猥〕
この発明は上記のような従来のものの欠点を除去するた
めになされたもので、光検知器を１合焦時のこれへの反
射光束を焦点位置様出ｙｃは吟とんど利用しないよう構
成することにより、追跡点のオフセットの少ない自動焦
点調節装置を提供することを目的としている。[Summary of the Invention] This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and the light flux reflected to the photodetector when it is in one focus is determined by the focus position yc. It is an object of the present invention to provide an automatic focusing device in which the offset of the tracking point is small by configuring the tracking point so that it is not used often.
以下この発明の一実施例を図１／Ｃついて説明する。 An embodiment of the present invention will be described below with reference to FIG. 1/C.
第３図ｄこの発明の一実施例である自動焦点調節装置６
において用いる光検知器の構成及びその接続例を示す概
略図で、他の衿・分は第１図、第２図と同−構成金有し
ている。図において、第２図と同一符号は同−或は相当
部分を示し、α０は５分割光検知器で、その中央部が円
形の分割線により外側部と区切られた中央領域（１８ｅ
）と、外側部がＸ。FIG. 3d Automatic focus adjustment device 6 which is an embodiment of the present invention
2 is a schematic diagram showing the configuration of a photodetector used in the invention and an example of its connection; other parts have the same configuration as in FIGS. 1 and 2. FIG. In the figure, the same reference numerals as those in FIG.
) and the outer part is X.
ｙ方向と４５°の角度葡もつ分割線で４分割された４分
割外ｇＩｌｌｌ領域（１８ａ）（１８ｂ）（１８ｃ）（
１８ｄ）とによシ構成されている。即ち、中央領域（１
８ｅ）が新たに設けられ、その位置′及び大きさが１合
焦時のそれへの反身」光スポット（９）の位ｆｆ＆及び
大きさとほぼ一致するか、僅かに小（い程度に設足され
る。The area outside the four divisions (18a) (18b) (18c) (
18d). That is, the central region (1
8e) is newly provided, and its position and size are approximately the same as the position and size of the light spot (9), or are slightly smaller than that at the time of one focus. be done.
そして焦点位置検出回路（１０）には４分割外（＋ｌｌ
ｉＪｔ域（１８ａ）（１８ｂ）（１８ｃ’）（１８ｄ
）のみが接続され、中央領域（１８ｅ）は、情報内生回
路（１′６に接続される。And the focus position detection circuit (10) is
iJt area (18a) (18b) (18c') (18d
) is connected, and the central region (18e) is connected to the information endogenous circuit (1'6).
次に、その動作を説明す′る。今、光ディスク（４）が
対物レンズ（３）Ｖこ近ずき過きると、光検知器αｂへ
の反射光スポットは（９Ｘ）のようになり、差動瑠猫器
Ｑ３＋の出力Ｅｆｉｄ正となり、対物１ノノズ（３）は
光ディスク（４）から遠ざかるよう制御される。逆に光
ディスク（４１が合焦点位置より遠さがり過きると。Next, its operation will be explained. Now, when the optical disk (4) passes close to the objective lens (3) V, the reflected light spot on the photodetector αb becomes as shown in (9X), and the output Efid of the differential runeko device Q3+ becomes positive. The objective 1 nozzle (3) is controlled to move away from the optical disk (4). On the other hand, if the optical disc (41) moves too far away from the focal point position.
反身づ光スポットは（９ｙ）のようＩ／Ｌｆ（す、差動
勅胛１器（１３）の出力Ｅｊは負となり、対物レンズ（
３１は光ディスク（４）に近ずくよう匍Ｈａされる。光
ディスク（４）が合焦点位置にある時は９反射光スポッ
ト（９）の大部分は中央領域（１８ｅ）上に入射し、外
側額板（１８ａ）（１８ｂ）（１８ｃ）（１８ｄ’）上
には殆ど人身１しな、い。従って合焦状態では、焦点付
１〜検出回路（１すの入力も出力も零に近い。もちろん
合焦時は１反射光スボソ入躬しても、加算器（Ｉｎ２＋
の出力はバランスしており、差動増幅器ＯＪの出力Ｋｆ
は苓である。４９生高ＩＮ波信号は中央領域（１８ｅ）
から得られる。The anti-body light spot is I/Lf (S) as shown in (9y), the output Ej of the differential force 1 unit (13) is negative, and the objective lens (
31 is placed close to the optical disc (4). When the optical disc (4) is at the focused position, most of the nine reflected light spots (9) are incident on the central area (18e) and on the outer forehead plates (18a) (18b) (18c) (18d'). There are almost no humans involved. Therefore, in the focused state, the input and output of the focusing circuit 1 to the detection circuit (1) are close to zero.
The output of the differential amplifier OJ is balanced, and the output Kf of the differential amplifier OJ
is a lily. 49 raw high IN wave signal is in the central region (18e)
obtained from.
；は映には戊刷尤か大引しないか１人制しでｔ血かな光
しか入力しない部族となっているので１反射レーザ光束
のパターンが変動しても、零点のドリフトが生じない。; is a tribe in which only one person is allowed to input light, whether it is printing or not, so even if the pattern of one reflected laser beam fluctuates, no drift of the zero point will occur.
即ち、第１図の従来例では。That is, in the conventional example shown in FIG.
合焦時には受光領域（８ａ）（８ｃ）に入力する強い光
に、受光領域（ａｂＭａａ）に入力する強い光がバラン
スして零の信号Ｂｆを生じていたわけであるから、光束
分布の変化はまともに零涜ドリフトに結ひつく。これに
対しこの発明では、上述のように合焦時には焦点位置検
出用の光検知器以下１領域に反射光束が殆ど入力しない
ので１反射光束分布が変わっても零点ドリフトが原理的
に発生しようかないわけである。At the time of focusing, the strong light entering the light receiving areas (8a) (8c) and the strong light entering the light receiving area (abMaa) were balanced and produced a zero signal Bf, so the change in the luminous flux distribution was normal. This leads to a zero sacrilege drift. On the other hand, in this invention, as mentioned above, when focusing, almost no reflected light flux is input to one area below the photodetector for detecting the focus position, so even if the distribution of one reflected light flux changes, zero point drift cannot occur in principle. That's why.
従って、半導体レーザ光束の分布変化などに強く、また
記録可能ディスクや記録消去可能ディスクなどのプリグ
ループからの回折による反Ｍｖ光束分非の変化に影響さ
れ難い自動焦点調節装置か構成できる。Therefore, it is possible to construct an automatic focusing device that is resistant to changes in the distribution of the semiconductor laser beam and is not easily affected by changes in the anti-Mv beam due to diffraction from the pre-group of recordable discs, recordable and erasable discs, etc.
以上の実施例では、初生信号を光検知器中央領域（１８
ｅ）から取出すよう構成したが、外１１Ｉｌｌ饋域（１
８ａ）（１８ｂ）（１８ｃ）（１８ｄ）の受光出力和か
ら再生信号を取出すようにしてもよい。In the above embodiment, the initial signal is transmitted to the central area of the photodetector (18
e), but the outer 11Ill domain (1
The reproduction signal may be extracted from the sum of the received light outputs of 8a), (18b), (18c), and (18d).
童だ、上記実施例では、光検知器中央領域（１８ｅ）が
円形の場合について勝明したが、Ｔｊ形や六角。In the above embodiment, the central region (18e) of the photodetector is circular, but it may also be Tj-shaped or hexagonal.
六角その他１閉ループの分割線で凶しｊられた他の形状
であっても、同様の効果ｋ 、４）ｊ−る。Similar effects can be achieved with hexagons and other shapes marked with a dividing line of one closed loop.
以上のように、この発ｇ」Ｖこよれは、非点収差方式の
自動焦点調節装置Ｖ（おいて、光検知器の中央部に、焦
点位置検出にあずからない独立した領域を設けるよう構
成シ、だので、零点のドリフトの少ない安定度の高いも
のが得られる効果がめる。As described above, this problem can be solved by using an astigmatic automatic focusing device (V), which is configured to provide an independent region in the center of the photodetector that does not participate in focal position detection. Therefore, the effect of obtaining high stability with less drift of the zero point can be seen.
第１図は、従来の非点収差方式系を使用した光デイスク
ヘッドの自動焦点調節装置１を示す概略光路図、第２図
はそれの光検知器以下のサーボイ汐＃＜７を示す概略図
、第３図はこの発明の一実施例Ｖ（おける光検知器の構
成及びその接続を・示す似略図である。
図において、（１）は光＋Ｊル、（３）は対９勿レンズ
、（４）は情報記録媒体でおる光テイスク、ｔ６Ｎ−ｔ
ビームスプＩＪ ツタ、（７）は非点収差光学素子であ
る円部レンズ。
（８ｒは４分割光検知番、 （１１は焦点位置検出回路
、旧）０りはその加算器、 （＋３１は差動増幅器、ａ
４）は情報検出回路、α５）はフォーカスアクチェータ
、 （ｌｔｉ＋はレンズ駆動回路、０８）は５分割光恢
知器、（１９θ）はそれの中央領域、（１９ａ’）（１
９ｂ）（１９ｃ）（１９ｄ）は外１１１１１９Ａ域であ
る。
図中同一符号は同−或は相当部分を示している。
代理人大岩増却（ほか２名）
第１図
１゛い
１！（
第２図
第３図
８Fig. 1 is a schematic optical path diagram showing an automatic focus adjustment device 1 for an optical disk head using a conventional astigmatism system, and Fig. 2 is a schematic diagram showing a servo tide #<7 below the photodetector. , FIG. 3 is a schematic diagram showing the configuration of a photodetector and its connections in one embodiment of the present invention (V). (4) is the optical take on the information recording medium, t6N-t
Beamsp IJ Ivy (7) is a circular lens which is an astigmatism optical element. (8r is the 4-split light detection number, (11 is the focal position detection circuit, old) 0 is its adder, (+31 is the differential amplifier, a
4) is the information detection circuit, α5) is the focus actuator, (lti+ is the lens drive circuit, 08) is the 5-split optical detector, (19θ) is its central region, (19a') (1
9b) (19c) (19d) are the outer 111119A area. The same reference numerals in the drawings indicate the same or corresponding parts. Agent Oiwa Increase (and 2 others) Figure 1 1-1! (Figure 2, Figure 3, Figure 8)
Claims (1)
のトラック上に集光させる対物ンンズ、上記光源からの
出射光来と上記記録媒体上の集光スポットからの上記対
物レンズを経ての反射光束を分離するビームスプリッタ
、この分＃ｌ：すれた反射光束に非点収差を与える光学
素子、この光学素子をへての反射光束を受光し、受光す
る反射ツＣスポットの形状変化によって異なった検知出
力を取出す光検知器、及びこの光検知器の出力から上記
記録媒体の上記対物レンズの合焦煮付Ｉｔからのずれに
応じた信号を取出す焦点位置検出回路を（＋ｉｉ＋え、
この検出回路の出力によシ上記対物レンズを光囮１方向
に駆動するようにした光デイスクヘッドの自動焦点調節
装置において、上記光検知器は、その中央部が閉ループ
状分割線により外側部と区切られた中央領域と、上記外
側部が、上記光学素子軸に対してはソ４５° の角度を
なす互にはソ直交する分割線により４分割された４分割
外側ｉ貝域との５分割構成とされ、この４分割外１０１
１領域のそれぞれ相対向する領域の受光出力和の差を上
記焦点付１ｈ検出回路により上記合焦点位置からのずれ
に応じた信号として取出すようにしたことを特徴とする
光デイスクヘッドの自動焦点調節装置６゜（２） 上記
光検知器の中央領域の位置及び太さざは１合焦時のこの
光検知器への反射光スポットの位置及び大きさとはソ一
致するようにしたことを％徴とする自動焦点訓１節装置
。 （３） 上記光検知器の中央領域から上記ｈ゛ｆ報Ｈ［
：録媒体からの情報再生出力をイ々することを特徴とす
る自動焦点調節装置。[Scope of Claims] (1) A light source, an objective lens that focuses the reflected light beam from the light source onto a track of an information recording medium, and a light beam emitted from the light source and the above from a focused spot on the recording medium. Beam splitter that separates the reflected light beam that passes through the objective lens, this part #l: an optical element that gives astigmatism to the grazed reflected light beam, and a reflection spot that receives the reflected light beam that passes through this optical element. (+ii+ picture,
In an automatic focusing device for an optical disk head, in which the objective lens is driven in one direction of the optical decoy by the output of the detection circuit, the central part of the optical detector is separated from the outer part by a closed loop dividing line. The divided central area and the outer shell area are divided into 5 parts by dividing lines which are perpendicular to each other and which form an angle of 45° with respect to the optical element axis. 101 outside this four-division
Automatic focusing adjustment of an optical disk head, characterized in that the difference in the sum of received light outputs of opposing areas in one area is extracted by the focused 1h detection circuit as a signal corresponding to the deviation from the focused position. Apparatus 6゜(2) The position and thickness of the central area of the photodetector are the same as the position and size of the reflected light spot on this photodetector at the time of one focus. Automatic focus training device with 1 section. (3) From the central area of the photodetector to the h゛f signal H[
: An automatic focus adjustment device that is characterized in that it reproduces and outputs information from a recording medium.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58191280A JPS6083229A (en) | 1983-10-13 | 1983-10-13 | Automatic focus adjusting device for optical disk head |
| EP19840110194 EP0137272B1 (en) | 1983-09-05 | 1984-08-28 | Automatic focusing device |
| DE8484110194T DE3484723D1 (en) | 1983-09-05 | 1984-08-28 | AUTOMATIC FOCUSING PROCESS. |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58191280A JPS6083229A (en) | 1983-10-13 | 1983-10-13 | Automatic focus adjusting device for optical disk head |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6083229A true JPS6083229A (en) | 1985-05-11 |
| JPH0554179B2 JPH0554179B2 (en) | 1993-08-11 |
Family
ID=16271927
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP58191280A Granted JPS6083229A (en) | 1983-09-05 | 1983-10-13 | Automatic focus adjusting device for optical disk head |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6083229A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6822209B2 (en) | 2000-11-15 | 2004-11-23 | Sharp Kabushiki Kaisha | Focal point dislocation detecting method and optical pickup apparatus |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS50104539A (en) * | 1974-01-15 | 1975-08-18 | ||
| JPS5339123A (en) * | 1976-09-22 | 1978-04-10 | Canon Inc | Automatic winder of cameras |
-
1983
- 1983-10-13 JP JP58191280A patent/JPS6083229A/en active Granted
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS50104539A (en) * | 1974-01-15 | 1975-08-18 | ||
| JPS5339123A (en) * | 1976-09-22 | 1978-04-10 | Canon Inc | Automatic winder of cameras |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6822209B2 (en) | 2000-11-15 | 2004-11-23 | Sharp Kabushiki Kaisha | Focal point dislocation detecting method and optical pickup apparatus |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0554179B2 (en) | 1993-08-11 |
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