JP2858772B2 - Optical playback device - Google Patents
Optical playback deviceInfo
- Publication number
- JP2858772B2 JP2858772B2 JP1025835A JP2583589A JP2858772B2 JP 2858772 B2 JP2858772 B2 JP 2858772B2 JP 1025835 A JP1025835 A JP 1025835A JP 2583589 A JP2583589 A JP 2583589A JP 2858772 B2 JP2858772 B2 JP 2858772B2
- Authority
- JP
- Japan
- Prior art keywords
- light
- medium
- optical
- signal
- 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.)
- Expired - Lifetime
Links
Landscapes
- Moving Of The Head For Recording And Reproducing By Optical Means (AREA)
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は光学的再生装置に関し、特に光磁気デイスク
装置のフオーカスサーボに関するものである。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical reproducing apparatus, and more particularly to a focus servo of a magneto-optical disc apparatus.
従来、この種の光学的再生装置は、レーザ発振器から
発した光束を光学的再生媒体に照射し、その反射光もし
くは透過光に含まれる情報信号を読み出すものである。
そして、このときのフオーカスサーボ引き込み動作は、
サーボループを開いた状態で対物レンズをランプ信号に
より駆動し、合焦位置を検知していた。Conventionally, this type of optical reproducing apparatus irradiates a light beam emitted from a laser oscillator onto an optical reproducing medium and reads out an information signal contained in the reflected light or transmitted light.
And the focus servo pull-in operation at this time is
With the servo loop open, the objective lens was driven by a ramp signal to detect the in-focus position.
上述した従来の光学的再生装置におけるフオーカスサ
ーボ引き込み動作は、ランプ信号を用いて対物レンズを
駆動している。この対物レンズは、通常板ばね等で支え
られており、応答対域が低いため、高速な信号で応答さ
せるためには大振幅の信号が必要となる。しかし、大振
幅の信号では引き込み動作が完了できなかつた場合、対
物レンズが光学的再生媒体面に衝突する危険があつた。In the focus servo pull-in operation in the conventional optical reproducing apparatus described above, the objective lens is driven using the ramp signal. Since this objective lens is usually supported by a leaf spring or the like and has a low response range, a signal having a large amplitude is required to respond with a high-speed signal. However, if the pull-in operation cannot be completed with a signal having a large amplitude, there is a danger that the objective lens will collide with the optical reproduction medium surface.
本発明の光学的再生装置は、前述した従来の課題を解
決するためになされたものであり、レーザ発振器から発
した光束を光学的再生媒体に照射し、その反射光もしく
は透過光に含まれる情報信号を読み出す光学的再生装置
において、前記レーザ発振器から発した光束を光学的再
生媒体上に集光する可動集光手段と、前記反射光もしく
は透過光の光路中に配置された光分配手段と、前記分配
手段により分配された一方の光路中に配置されたサーボ
誤差信号光検出手段と、前記可動集光手段を光学的再生
媒体に垂直に駆動する駆動手段と、前記サーボ誤差信号
光検出手段の出力信号を入力とし、媒体上に常に光束の
焦点を結ばせるように駆動手段を制御するフォーカスサ
ーボ手段とを備え、フォーカスサーボ引き込み動作にお
いて、前記可動集光手段を媒体から一度遠ざけた後に媒
体に近づける際に、前記可動集光手段が完全に追従した
場合においても前記媒体に接触しない正負それぞれ所定
の振幅値を持つ矩形信号を駆動手段に与え、合焦位置を
検知したとき直ちにフォーカスサーボループをオンにす
るようにしたものである。An optical reproducing apparatus according to the present invention has been made to solve the above-mentioned conventional problems, and irradiates a light beam emitted from a laser oscillator to an optical reproducing medium, and reflects information contained in reflected light or transmitted light thereof. In an optical reproducing device that reads out a signal, a movable light condensing unit that condenses a light beam emitted from the laser oscillator on an optical reproducing medium, and a light distribution unit that is disposed in an optical path of the reflected light or the transmitted light. A servo error signal light detecting means arranged in one of the optical paths distributed by the distributing means, a driving means for driving the movable condensing means perpendicular to an optical reproduction medium, and a servo error signal light detecting means. A focus servo unit that receives an output signal as input and controls a driving unit so that a light beam is always focused on a medium. When the step is moved away from the medium once and then close to the medium, even when the movable light-collecting means completely follows, the rectangular signal having a predetermined amplitude value of positive and negative which does not come into contact with the medium is given to the driving means, and focusing is performed. When the position is detected, the focus servo loop is immediately turned on.
本発明においては、フオーカスサーボ手段のサーボル
ープ引き込み時に可動集光手段を矩形信号により駆動す
る。In the present invention, the movable focusing means is driven by a rectangular signal when the focus servo means pulls in the servo loop.
次に本発明について図面を参照して説明する。 Next, the present invention will be described with reference to the drawings.
第１図は本発明による光学的再生装置を光磁気デイス
ク装置のフオーカスサーボに応用した一実例を示すブロ
ツク図である。同図において、１は半導体レーザ、２は
コリメートレンズ、３はビーム成形プリズム、4,5はビ
ームスプリツタ、６は対物レンズ、７は光学的再生媒体
としての光磁気デイスクである。８は磁界発生装置、９
は集光レンズ、10はナイフ、11は２分割フオーカスエラ
ー光検出器、12は集光レンズ、13は情報信号光検出器、
14は対物レンズ駆動コイル、15はフオーカスサーボ回路
である。FIG. 1 is a block diagram showing an example in which an optical reproducing apparatus according to the present invention is applied to a focus servo of a magneto-optical disc apparatus. In the figure, 1 is a semiconductor laser, 2 is a collimating lens, 3 is a beam shaping prism, 4 and 5 are beam splitters, 6 is an objective lens, and 7 is a magneto-optical disk as an optical reproduction medium. 8 is a magnetic field generator, 9
Is a condenser lens, 10 is a knife, 11 is a two-part focusing error light detector, 12 is a condenser lens, 13 is an information signal light detector,
Reference numeral 14 denotes an objective lens driving coil, and reference numeral 15 denotes a focus servo circuit.
次に動作について説明する。 Next, the operation will be described.
まず、半導体レーザ１が発したレーザ光は、コリメー
トレンズ2,ビーム成形プリズム3,ビームスプリツタ4,5
および対物レンズ６を通り、光磁気デイスク７に到達す
る。つぎに光磁気デイスク７で反射したレーザ光は、ビ
ームスプリツタ4,5で分配され、集光レンズ9,12を通
り、２分割フオーカスエラー光検出器11および情報信号
光検出器13に到達する。フオーカスサーボ回路15では、
２分割フオーカスエラー光検出器11の２出力の差信号が
零となるように対物レンズ駆動コイル14を制御し、合焦
状態を維持する。なお、上述の例においては、フオーカ
スサーボ方式として公知のナイフエツジ方式を用いてい
る。First, the laser light emitted by the semiconductor laser 1 is applied to a collimating lens 2, a beam shaping prism 3, and beam splitters 4, 5,
Then, the light passes through the objective lens 6 and reaches the magneto-optical disk 7. Next, the laser light reflected by the magneto-optical disk 7 is distributed by the beam splitters 4 and 5, passes through the condenser lenses 9 and 12, and reaches the two-part focus error light detector 11 and the information signal light detector 13. I do. In the focus servo circuit 15,
The objective lens driving coil 14 is controlled so that the difference signal between the two outputs of the two-part focus error light detector 11 becomes zero, and the focused state is maintained. In the above-described example, a known knife edge method is used as a focus servo method.
以上にフオーカスサーボ回路の再生時における動作を
説明した。実際の装置においては、電源投入後、半導体
レーザ１を発光させた後にフオーカスエラー波形を監視
しながら、対物レンズ６を一度遠ざけ、媒体に近づけ
る。合焦位置を検知してサーボループを閉じる。このと
き、レンズ駆動信号として第２図（ａ）に示すような矩
形信号を入力する。この場合、この矩形信号の振幅値は
レンズが完全に追従した場合においても媒体に接触しな
い値に調整をする。第２図（ｂ）に示すフオーカスエラ
ー信号はA/D変換を行ない、CPUで監視している。合焦位
置を検知した後、直ちにCPUから第２図（ｃ）に示す
「Ｌ」レベルのサーボループオンのコントロール信号が
出力される。The operation during reproduction of the focus servo circuit has been described above. In an actual apparatus, after the power is turned on, the objective lens 6 is once moved away from the medium while monitoring the focus error waveform after the semiconductor laser 1 emits light. Detects the in-focus position and closes the servo loop. At this time, a rectangular signal as shown in FIG. 2A is input as a lens drive signal. In this case, the amplitude value of this rectangular signal is adjusted to a value that does not contact the medium even when the lens completely follows. The focus error signal shown in FIG. 2B performs A / D conversion and is monitored by the CPU. Immediately after detecting the in-focus position, the CPU outputs an "L" level servo loop-on control signal shown in FIG. 2 (c).
以上説明したように本発明は、フオーカスサーボ引き
込み動作において、矩形信号を用いてレンズを駆動する
ことにより、迅速に安全にサーボ引き込み動作を行なう
ことができるという極めて優れた効果が得られる。As described above, according to the present invention, in the focus servo pull-in operation, by driving the lens using a rectangular signal, an extremely excellent effect that the servo pull-in operation can be performed quickly and safely can be obtained.
第１図は本発明の一実施例を示すブロツク図、第２図
（ａ），（ｂ），（ｃ）は第１図のフオーカスサーボ回
路においてサーボ引き込み時におけるレンズ駆動信号，
フオーカスエラー信号およびサーボループ信号のタイミ
ングを示す波形図である。 １……レーザ発振器、２……コリメートレンズ、３……
ビーム成形プリズム、4,5……ビームスプリツタ、６…
…対物レンズ、７……光磁気デイスク、８……磁界発生
装置、9,12……集光レンズ、10……ナイフ、11……２分
割フオーカスエラー光検出器、13……情報信号光検出
器、14……対物レンズ駆動コイル、15……フオーカスサ
ーボ回路。FIG. 1 is a block diagram showing an embodiment of the present invention. FIGS. 2 (a), 2 (b) and 2 (c) show lens drive signals during servo pull-in in the focus servo circuit of FIG.
FIG. 4 is a waveform chart showing timings of a focus error signal and a servo loop signal. 1 ... laser oscillator, 2 ... collimating lens, 3 ...
Beam forming prism, 4,5 …… Beam splitter, 6…
... Objective lens, 7 ... Magneto-optical disk, 8 ... Magnetic field generator, 9,12 ... Condenser lens, 10 ... Knife, 11 ... Two split focus error light detector, 13 ... Information signal light Detector, 14 ... Objective lens drive coil, 15 ... Focus servo circuit.
Claims (1)
媒体に照射し、その反射光もしくは透過光に含まれる情
報信号を読み出す光学的再生装置において、 前記レーザ発振器から発した光束を光学的再生媒体上に
集光する可動集光手段と、 前記反射光もしくは透過光の光路中に配置された光分配
手段と、 前記分配手段により分配された一方の光路中に配置され
たサーボ誤差信号光検出手段と、 前記可動集光手段を光学的再生媒体に垂直に駆動する駆
動手段と、 前記サーボ誤差信号光検出手段の出力信号を入力とし、
媒体上に常に光束の焦点を結ばせるように駆動手段を制
御するフォーカスサーボ手段とを備え、フォーカスサー
ボ引き込み動作において、前記可動集光手段を媒体から
一度遠ざけた後に媒体に近づける際に、前記可動集光手
段が完全に追従した場合においても前記媒体に接触しな
い正負それぞれ所定の振幅値を持つ矩形信号を駆動手段
に与え、合焦位置を検知したとき直ちにフォーカスサー
ボループをオンにすることを特徴とした光学的再生装
置。An optical reproducing apparatus for irradiating a light beam emitted from a laser oscillator onto an optical reproduction medium and reading an information signal contained in reflected light or transmitted light thereof, wherein the light beam emitted from the laser oscillator is optically reproduced. Movable condensing means for converging light on a medium; light distributing means disposed in an optical path of the reflected light or transmitted light; and servo error signal light detection disposed in one of the optical paths distributed by the distributing means. Means, a driving means for vertically driving the movable condensing means to an optical reproduction medium, and an output signal of the servo error signal light detection means as an input,
A focus servo means for controlling a driving means so that a light beam is always focused on the medium; and in the focus servo pull-in operation, when moving the movable light condensing means once away from the medium and then approaching the medium, Even when the light focusing means completely follows, a rectangular signal having a predetermined amplitude value for each of the positive and negative sides which does not come into contact with the medium is given to the driving means, and the focus servo loop is turned on immediately when the in-focus position is detected. Optical playback device.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1025835A JP2858772B2 (en) | 1989-02-06 | 1989-02-06 | Optical playback device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1025835A JP2858772B2 (en) | 1989-02-06 | 1989-02-06 | Optical playback device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH02206026A JPH02206026A (en) | 1990-08-15 |
| JP2858772B2 true JP2858772B2 (en) | 1999-02-17 |
Family
ID=12176917
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1025835A Expired - Lifetime JP2858772B2 (en) | 1989-02-06 | 1989-02-06 | Optical playback device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2858772B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SG86327A1 (en) * | 1998-07-16 | 2002-02-19 | Motorola Inc | Message transmission by a multichannel synchronous selective call communication system |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63217533A (en) * | 1987-03-04 | 1988-09-09 | Fujitsu Ltd | Focus lead-in system |
-
1989
- 1989-02-06 JP JP1025835A patent/JP2858772B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH02206026A (en) | 1990-08-15 |
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