JPH0736228B2 - Automatic focus pull-in control device - Google Patents
Automatic focus pull-in control deviceInfo
- Publication number
- JPH0736228B2 JPH0736228B2 JP7692787A JP7692787A JPH0736228B2 JP H0736228 B2 JPH0736228 B2 JP H0736228B2 JP 7692787 A JP7692787 A JP 7692787A JP 7692787 A JP7692787 A JP 7692787A JP H0736228 B2 JPH0736228 B2 JP H0736228B2
- Authority
- JP
- Japan
- Prior art keywords
- signal
- focus
- lens
- focus error
- disc
- 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.)
- Expired - Lifetime
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
- G11B7/08—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
- G11B7/0945—Methods for initialising servos, start-up sequences
Description
【発明の詳細な説明】 産業上の利用分野 本発明は、光方式の情報記録再性装置に用いられる自動
焦点引き込み制御装置に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic focus pull-in control device used in an optical information recording / reproducing device.
従来の技術 近年、レーザ光を利用してディスクに情報信号を記録
し、あるいはディスクから情報信号を再生する光方式の
情報記録再生装置の開発がなされている。2. Description of the Related Art In recent years, an optical information recording / reproducing apparatus for recording an information signal on a disc or reproducing an information signal from the disc using a laser beam has been developed.
この情報記録再性装置には、光ピックアップの光学系に
より直径１μｍ程度に絞り込まれた光ビームの焦点をデ
ィスクの面振れに追随させながらディスクの信号記録面
に合焦点させるためのフォーカスサーボの技術が不可欠
である。This information recording / reproducing apparatus has a focus servo technique for focusing the light beam, which is narrowed to a diameter of about 1 μm by the optical system of the optical pickup, on the signal recording surface of the disk while following the surface wobbling of the disk. Is essential.
第２図は絞りレンズとディスクの信号記録面の距離に対
するフォーカス誤差信号の関係を示したものである。絞
りレンズ11とディスクの信号記録面12との距離をｄ、フ
ォーカス誤差信号をFEとすると第２図ａのd1,d2,d3,d4,
d5が第２図ｂのd1,d2,d3,d4,d5に対応する。第２図ｂの
点d2から点d4の範囲がフォーカスループの引き込み範囲
であり、絞りレンズ11が前記引き込み範囲に入った時に
フォーカスループを閉じることにより、フォーカスサー
ボが作動する。FIG. 2 shows the relationship between the focus error signal and the distance between the diaphragm lens and the signal recording surface of the disc. Assuming that the distance between the aperture lens 11 and the signal recording surface 12 of the disc is d and the focus error signal is FE, d1, d2, d3, d4,
d5 corresponds to d1, d2, d3, d4, d5 in FIG. 2b. The range from the point d2 to the point d4 in FIG. 2B is the pull-in range of the focus loop. When the diaphragm lens 11 enters the pull-in range, the focus loop is closed to activate the focus servo.
第３図は前記フォーカスループの引き込み範囲に絞りレ
ンズが入ったことを検出する方式の例であり、フォーカ
ス誤差信号FEと一定のスライス信号が比較器13で比較さ
れ、第４図のようにゲート信号の極性変化によりスイッ
チ15を閉じ、フォーカスサーボを作動させる技術が一般
的に用いられている。（例えば、特開昭60−506633号公
報） 発明が解決しようとする問題点 このような従来の技術では、記録済みの部分と未記録の
部分で反射率が異なるような記録材料を用いたディスク
では同一ディスクでも場所によってフォーカス誤差信号
の振幅が変化し、引き込み範囲の検出タイミングがばら
ついたり、ホコリ等で光伝達効率が低下した場合反射率
の低い部分では引き込み点を検出しなくなるという問題
があった。FIG. 3 shows an example of a method for detecting that the aperture lens has entered the pull-in range of the focus loop. The focus error signal FE and a fixed slice signal are compared by the comparator 13, and gates are output as shown in FIG. A technique of closing the switch 15 and operating the focus servo by changing the polarity of the signal is generally used. (For example, Japanese Patent Laid-Open No. 60-506633) Problems to be Solved by the Invention In such a conventional technique, a disc using a recording material in which a reflectance is different between a recorded portion and an unrecorded portion However, even with the same disc, the amplitude of the focus error signal changes depending on the location, the detection timing of the pull-in range varies, and if the light transmission efficiency decreases due to dust, etc., the pull-in point will not be detected in the portion with low reflectance. It was
本発明は、かかる点に鑑みてなされたもので、簡易な構
成で安定にフォーカスの引き込み点を検出する自動焦点
引き込み制御装置を提供することを目的としている。The present invention has been made in view of the above points, and an object thereof is to provide an automatic focus pull-in control device that stably detects a focus pull-in point with a simple configuration.
問題点を解決するための手段 本発明は、上記問題点を解決するため、絞りレンズをデ
ィスクの信号記録面に近付つけてフォーカス誤差信号の
ピークを保持した後、絞りレンズをディスク記録面から
遠ざけ、再び絞りレンズをディスクの信号記録面に近付
け、保持したフォーカス誤差信号のピーク値を用い、フ
ォーカス誤差信号がそのピーク値またはそれ以下になっ
たときに引き込み検出信号を得てフォーカスサーボルー
プを閉じるようにしたものである。Means for Solving the Problems In order to solve the above-mentioned problems, according to the present invention, an aperture lens is brought close to a signal recording surface of a disc to hold a peak of a focus error signal, and then the aperture lens is moved from the disc recording surface. Move it away, bring the aperture lens close to the signal recording surface of the disc again, and use the peak value of the focus error signal that was held.When the focus error signal reaches or falls below that peak value, the pull-in detection signal is obtained to form the focus servo loop. It was closed.
また、ディスクのキズ等でピーク値の誤検出をしないよ
うに絞りレンズをディスクの信号記録面に近付けてピー
クを保持した後、絞りレンズをディスク記録面から遠ざ
け、再び絞りレンズをディスクの信号記録めに近付け、
保持したピーク値を用い、引き込み検出信号を得るもの
である。To prevent the peak value from being erroneously detected due to scratches on the disc, hold the peak by bringing the aperture lens closer to the signal recording surface of the disc, then move the aperture lens away from the disc recording surface, and then record the aperture lens again on the disc signal recording surface. Get closer,
The pull-in detection signal is obtained by using the held peak value.
作用 本発明は、上記した構成により、装置が動作する毎にピ
ーク値を検出し、スライス信号を得ることによってディ
スクの反射率の違いや光伝達効率の変化によっても安定
して引き込み検出信号を得ことができる。Effect of the Invention With the above-described configuration, the present invention detects the peak value each time the device operates, and obtains the slice signal to stably obtain the pull-in detection signal even if the reflectance of the disc is different or the light transmission efficiency is changed. be able to.
実施例 第１図は本発明の一実施例の自動焦点引き込み制御装置
を示すブロック図である。第１図における自動焦点引き
込み制御装置は、光検出器から送られてくるフォーカス
誤差信号FEのピークを保持するピーク保持器１と、ピー
ク保持器で保持されたピークを１〜数分の１に減少させ
るアッテネータ２と、そのアッテネータからの出力とフ
ォーカス誤差信号FEを比較する比較器３と、比較器の出
力信号の極性の変化をカウントし、あらかじめ設定して
ある回数の極性変化の時にゲート信号を出力するカウン
タ回路４と、カウンタ回路の出力に応じてオン・オフさ
れるスイッチ５と、フォーカス誤差信号FEの位相補償を
行なわせる位相補償回路６と、フォーカススタート信号
によって所定のランプ信号を発生するランプ信号発生回
路７と、そのランプ信号を絞りレンズ駆動装置10を駆動
させるドライブ回路９に加算させる加算回路８とによっ
て構成されている。Embodiment FIG. 1 is a block diagram showing an automatic focus pull-in control device according to an embodiment of the present invention. The automatic focus pull-in control device in FIG. 1 reduces the peak held by the peak holder 1 that holds the peak of the focus error signal FE sent from the photodetector and the peak held by the peak holder to 1 to several times. Attenuator 2 to decrease, comparator 3 that compares the output from the attenuator with the focus error signal FE, and the change in the polarity of the output signal of the comparator is counted, and the gate signal is detected when the polarity changes a preset number of times. A counter circuit 4 that outputs a signal, a switch 5 that is turned on / off according to the output of the counter circuit, a phase compensation circuit 6 that performs phase compensation of the focus error signal FE, and a predetermined ramp signal generated by the focus start signal. Ramp signal generating circuit 7 and an adder circuit 8 for adding the ramp signal to a drive circuit 9 for driving the aperture lens driving device 10. It is constituted by.
このように構成された本発明による自動焦点引き込み制
御装置の動作について説明する。The operation of the automatic focus pull-in control device according to the present invention configured as described above will be described.
まず、フォーカススタート信号によって所定のランプ信
号をランプ信号発生回路７が発生する。この時ゲート回
路５はオフされている。ランプ信号は加算回路８に加算
され、その出力はドライブ回路９を通って絞りレンズ駆
動装置10に送られ駆動制御が行なわれるため絞りレンズ
11は定速でディスクの信号記録面12に近付く。First, the ramp signal generation circuit 7 generates a predetermined ramp signal according to the focus start signal. At this time, the gate circuit 5 is off. The ramp signal is added to the adder circuit 8, and the output thereof is sent to the aperture lens driving device 10 through the drive circuit 9 so that drive control is performed.
11 is a constant speed and approaches the signal recording surface 12 of the disc.
その後、光検出器によって検出されたフォーカス誤差信
号FEはピーク保持器１に入力され、フォーカス誤差信号
FEのピークが保持され、そのピーク値をアッテネータで
分割したスライス信号が比較器３に出力される。一方、
比較器３にはフォーカス誤差信号FEも入力されており、
このスライス信号と比較し、フォーカス引き込みの検出
信号をカウンタ回路４に出力する。カウンタ回路４はフ
ォーカス引き込み検出信号が何回入力されたかをカウン
トし、カウント数が１の時はゲート回路５をオン信号を
出力せずにランプ信号発生回路７をリセットし、ランプ
信号を初期値にする。これにより、絞りレンズ11はディ
スクの信号記録面12から遠ざかる。Then, the focus error signal FE detected by the photodetector is input to the peak holder 1 and the focus error signal FE is input.
The peak of FE is held, and a slice signal obtained by dividing the peak value by the attenuator is output to the comparator 3. on the other hand,
The focus error signal FE is also input to the comparator 3,
The focus pull-in detection signal is output to the counter circuit 4 in comparison with this slice signal. The counter circuit 4 counts the number of times the focus pull-in detection signal is input. When the count number is 1, the gate circuit 5 does not output an ON signal and resets the ramp signal generation circuit 7 to reset the ramp signal to an initial value. To As a result, the diaphragm lens 11 moves away from the signal recording surface 12 of the disc.
次に、再びフォーカススタート信号が入力され、前記と
同様に絞りレンズ11はディスクの信号記録面12に近付
き、フォーカス誤差信号FEが得られる。このフォーカス
誤差信号FEと、ピーク保持器１に入力され保持されたフ
ォーカス誤差信号FEのピーク値をアッテータ２で分割し
たスライス信号が比較器３で比較され、引き込み検出信
号をカウンタ回路４に出力する。カウンタ回路４は今度
はカウント数が２であるため、ゲート回路５にオン信号
を出力し、フォーカスサーボループを閉じると同時にラ
ンプ信号発生回路７の出力を止める。Next, the focus start signal is input again, and the diaphragm lens 11 approaches the signal recording surface 12 of the disc in the same manner as described above, and the focus error signal FE is obtained. The focus error signal FE and the slice signal obtained by dividing the peak value of the focus error signal FE input to and held in the peak holder 1 by the attenuator 2 are compared by the comparator 3, and the pull-in detection signal is output to the counter circuit 4. . Since the count number of the counter circuit 4 is 2 this time, the counter circuit 4 outputs an ON signal to the gate circuit 5 to close the focus servo loop and simultaneously stop the output of the ramp signal generating circuit 7.
このように、本装置は、フォーカス誤差信号のピークを
保持し、そのピーク値をアッテネータで分割した信号を
スライス信号に用いることと、絞りレンズを１度ディス
クの信号記録面に近付けフォーカス誤差信号のピークを
確実に保持し、２回目以後にフォーカスループを閉じデ
ィスクのキズ等による誤検出を無くすことを特徴とした
もので、前記のランプ信号発生回路７やカウンタ回路４
等の方式は前記方式に限定されない。As described above, the present apparatus holds the peak of the focus error signal, uses the signal obtained by dividing the peak value by the attenuator as the slice signal, and brings the aperture lens once closer to the signal recording surface of the disc to obtain the focus error signal. It is characterized in that the peak is surely held and the focus loop is closed after the second time to eliminate erroneous detection due to scratches on the disk.
The method such as is not limited to the above method.
発明の効果 以上のように、本発明によれば、きわめて簡易な回路構
成で、ディスクのキズ等による誤検出の無い、安定でか
つ確実にフォーカスを引き込ませることができ、実用的
にきわめて有用である。EFFECTS OF THE INVENTION As described above, according to the present invention, it is possible to pull the focus stably and surely without an erroneous detection due to a scratch on the disk with a very simple circuit configuration, which is extremely useful in practice. is there.
第１図は本発明の一実施例における自動焦点引き込み制
御装置を示すブロック図、第２図はディスクの信号記録
面と絞りレンズの距離に対するフォーカス誤差信号を示
す特性図、第３図は従来例の一般的な自動焦点引き込み
制御装置を示すブロック図、第４図はそのスライス信号
とフォーカス誤差信号に対するゲート信号を示す波形図
である。 １……ピーク保持器、２……アッテネータ、３……比較
器、４……カウンタ回路、５……スイッチ、６……位相
補償回路、７……ランプ信号発生回路、８……加算回
路、９……ドライブ回路、10……絞りレンズ駆動装置、
11……絞りレンズ、12……ディスクの信号記録面、13…
…比較器、14……位相補償回路、15……スイッチ。FIG. 1 is a block diagram showing an automatic focus pull-in control device according to an embodiment of the present invention, FIG. 2 is a characteristic diagram showing a focus error signal with respect to a distance between a signal recording surface of a disc and a diaphragm lens, and FIG. 3 is a conventional example. FIG. 4 is a block diagram showing a general automatic focus pull-in control device, and FIG. 4 is a waveform diagram showing a gate signal for the slice signal and the focus error signal. 1 ... Peak holder, 2 ... Attenuator, 3 ... Comparator, 4 ... Counter circuit, 5 ... Switch, 6 ... Phase compensation circuit, 7 ... Ramp signal generating circuit, 8 ... Adding circuit, 9: drive circuit, 10: diaphragm lens drive device,
11 ... Aperture lens, 12 ... Disc signal recording surface, 13 ...
… Comparator, 14 …… Phase compensation circuit, 15 …… Switch.
Claims (1)
フォーカス誤差信号と、光ビームを前記ディスクの信号
記録面上に収束させる絞りレンズを駆動する駆動装置
と、前記絞りレンズを前記信号記録面に近付けて行くよ
うな絞りレンズ駆動信号を発生する手段と、前記フォー
カス誤差信号のピークを保持する手段を備え、前記駆動
装置により前記絞りレンズを前記絞りレンズ駆動信号で
駆動し、絞りレンズを信号記録面に近付け、フォーカス
誤差信号のピーク値を保持した状態で絞りレンズを信号
記録面から遠ざけ、再び絞りレンズを信号記録面に近付
け、保持しているフォーカス誤差信号のピーク値または
ピーク値以下になった時にフォーカスサーボループを閉
じる手段とを備えたことを特徴とする自動焦点引き込み
制御装置。1. A focus error signal obtained by detecting reflected light from a disc, a driving device for driving a diaphragm lens that converges a light beam on a signal recording surface of the disc, and the diaphragm lens for recording the signal. A means for generating an aperture lens drive signal that approaches the surface and a means for holding the peak of the focus error signal are provided, and the drive device drives the aperture lens with the aperture lens drive signal to drive the aperture lens. Move the iris lens away from the signal recording surface while keeping the peak value of the focus error signal close to the signal recording surface, then bring the iris lens closer to the signal recording surface again and keep it below the peak value or peak value of the focus error signal And a means for closing the focus servo loop when it becomes the automatic focus pull-in control device.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7692787A JPH0736228B2 (en) | 1987-03-30 | 1987-03-30 | Automatic focus pull-in control device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7692787A JPH0736228B2 (en) | 1987-03-30 | 1987-03-30 | Automatic focus pull-in control device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63244321A JPS63244321A (en) | 1988-10-11 |
| JPH0736228B2 true JPH0736228B2 (en) | 1995-04-19 |
Family
ID=13619352
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7692787A Expired - Lifetime JPH0736228B2 (en) | 1987-03-30 | 1987-03-30 | Automatic focus pull-in control device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0736228B2 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02223023A (en) * | 1989-02-23 | 1990-09-05 | Matsushita Electric Ind Co Ltd | Focus leading-in device |
| JPH02254634A (en) * | 1989-03-28 | 1990-10-15 | Matsushita Electric Ind Co Ltd | Method for setting position of objective lens in automatic focus controller |
| JP4831928B2 (en) * | 2000-03-03 | 2011-12-07 | 株式会社ソニー・コンピュータエンタテインメント | Focus control device, recording medium, and optical disk reproducing device |
| JPWO2007032381A1 (en) | 2005-09-14 | 2009-03-19 | パナソニック株式会社 | Optical disk device |
-
1987
- 1987-03-30 JP JP7692787A patent/JPH0736228B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS63244321A (en) | 1988-10-11 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EXPY | Cancellation because of completion of term |