JPS6235149Y2 - - Google Patents
Info
- Publication number
- JPS6235149Y2 JPS6235149Y2 JP1980168759U JP16875980U JPS6235149Y2 JP S6235149 Y2 JPS6235149 Y2 JP S6235149Y2 JP 1980168759 U JP1980168759 U JP 1980168759U JP 16875980 U JP16875980 U JP 16875980U JP S6235149 Y2 JPS6235149 Y2 JP S6235149Y2
- Authority
- JP
- Japan
- Prior art keywords
- objective lens
- focus servo
- amplifier
- lens driving
- servo device
- 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
Links
- 230000003287 optical effect Effects 0.000 claims 1
- 230000005669 field effect Effects 0.000 description 7
- 229920006395 saturated elastomer Polymers 0.000 description 5
- 239000003990 capacitor Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000002238 attenuated effect Effects 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 238000009499 grossing Methods 0.000 description 1
Landscapes
- Moving Of The Head For Recording And Reproducing By Optical Means (AREA)
- Optical Recording Or Reproduction (AREA)
Description
【考案の詳細な説明】
本考案はビデオデイスクプレーヤのフオーカス
サーボ装置の改良に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a focus servo device for a video disc player.
本明細書においてフオーカスサーボ装置とはビ
デオデイスクプレーヤの対物レンズをデイスクに
対して垂直な方向に移動させるサーボ装置をい
う。 In this specification, the focus servo device refers to a servo device that moves the objective lens of a video disk player in a direction perpendicular to the disk.
ビデオデイスクプレーヤにおいて、所定のフレ
ームを選択するランダムアクセスの為にトラツキ
ングサーボルーブを開放してデイスクの直径方向
に対物レンズを移動させる。この場合、公知の４
分割デイテクタを用いてフオーカスサーボを行な
う場合、通常のプレイ状態のときはトラツキング
サーボクローズ、フオーカスサーボオンのため、
夫々２つのデイテクタの和出力の差は等しくなる
ように制御されるため、フオーカスサーボ装置の
対物レンズ駆動用増幅器が飽和することはない
が、ランダムアクセス指令等のスキヤン指令に基
づいてランダムアクセスする時は、トラツキング
サーボループを開放（オープン）して、対物レン
ズをデイスクの径方向に急速に移動させてジヤン
プ動作等を行なう。このとき、ピツクアツプはト
ラツク間を横切るため、各トラツク間の像、すな
わちトラツキング成分が４分割されたデイテクタ
上に光の強弱として現われてくる。このトラツキ
ング成分が、各デイテクタの和出力の差として現
われ、その和出力の差が等しければよいが、実際
には、その和出力の差が大きくなり、フオーカス
サーボの出力となるため、フオーカスサーボ装置
の対物レンズ駆動用増幅器が飽和してしまう。対
物レンズ駆動用増幅器が飽和すれば、上下に動い
ている対物レンズの動作基準点が大きくずれ、所
謂対物レンズのオフセツトが大きくなり、ランダ
ムアクセスに必要なフレーム番号の読取りが不可
能となる欠点があつた。 In a video disc player, a tracking servo lube is opened to move an objective lens in the diametrical direction of the disc for random access to select a predetermined frame. In this case, the known 4
When performing focus servo using a split detector, the tracking servo is closed and the focus servo is on during normal play, so
Since the difference between the sum outputs of the two detectors is controlled to be equal, the amplifier for driving the objective lens of the focus servo device does not become saturated, but random access is performed based on a scan command such as a random access command. At this time, the tracking servo loop is opened and the objective lens is rapidly moved in the radial direction of the disk to perform a jump operation or the like. At this time, since the pick-up crosses between the tracks, the image between each track, that is, the tracking component, appears as the intensity of light on the four-divided detector. This tracking component appears as a difference between the sum outputs of each detector, and it is fine if the sum output differences are equal, but in reality, the difference between the sum outputs becomes large and becomes the output of the focus servo, so the focus The amplifier for driving the objective lens of the servo device becomes saturated. If the objective lens drive amplifier becomes saturated, the operating reference point of the objective lens that is moving up and down will shift significantly, resulting in a large so-called objective lens offset, which has the disadvantage of making it impossible to read the frame number required for random access. It was hot.
本考案は上記にかんがみなされたもので、上記
の欠点を解消したフオーカスサーボ装置を提供す
ることを目的とするものであつて、以下本考案を
実施例により説明する。 The present invention has been made in view of the above, and aims to provide a focus servo device that eliminates the above-mentioned drawbacks.The present invention will be described below with reference to examples.
図面は本考案の一実施例のブロツク図である。
第１図において、１はバツフア増幅器であり、２
はバツフア増幅器１の出力を分圧する閉ループ利
得調整用の可変抵抗であり、３は可変抵抗２の出
力を入力とする対物レンズ駆動用増幅器であり、
４は対物レンズ駆動用コイルであり、対物レンズ
駆動用増幅器３で駆動される。バツフア増幅器
１、可変抵抗２、対物レンズ駆動用増幅器３およ
びコイル４とでフオーカスサーボ装置を構成して
いる。 The drawing is a block diagram of an embodiment of the present invention.
In FIG. 1, 1 is a buffer amplifier, and 2
is a variable resistor for closed loop gain adjustment that divides the output of the buffer amplifier 1; 3 is an objective lens driving amplifier that receives the output of the variable resistor 2;
Reference numeral 4 denotes an objective lens driving coil, which is driven by the objective lens driving amplifier 3. A focus servo device is composed of a buffer amplifier 1, a variable resistor 2, an objective lens driving amplifier 3, and a coil 4.
一方、対物レンズ駆動用増幅器３の出力を結合
用コンデンサ５を通して取り出し、ダイオード６
で検波し、コンデンサ７からなる平滑回路で平滑
して対物レンズ駆動用増幅器３の入力端とアース
との間にそれぞれドレイン・ソースを接続した電
界効果トランジスタ８のゲートに印加する自動利
得制御回路を対物レンズ駆動用増幅器３に設け
る。なお電界効果トランジスタ８のゲートに電源
−Ｂを接続して電界効果トランジスタ８のゲート
に所定のバイアス電圧を印加してある。 On the other hand, the output of the objective lens driving amplifier 3 is taken out through a coupling capacitor 5, and a diode 6
An automatic gain control circuit detects the wave, smoothes it with a smoothing circuit consisting of a capacitor 7, and applies the signal to the gate of a field effect transistor 8 whose drain and source are connected between the input terminal of the objective lens driving amplifier 3 and the ground, respectively. It is provided in the objective lens driving amplifier 3. Note that a power source -B is connected to the gate of the field effect transistor 8, and a predetermined bias voltage is applied to the gate of the field effect transistor 8.
そこでいま対物レンズ駆動用増幅器３の入力が
所定値より増大したときは対物レンズ駆動用増幅
器３の出力は、整流され平滑されて電界効果トラ
ンジスタ８のゲート電圧を増加させる。そこで電
界効果トランジスタ８のドレイン・ソース間の抵
抗を減少させる。従つて前記した如くランダムア
クセスの為に対物レンズ駆動用増幅器３への入力
信号が通常の画像再生動作中の入力に対して数倍
から数十倍となつたとしても、対物レンズ駆動用
増幅器３は自動利得制御作用が働き対物レンズ駆
動用増幅器３は飽和することはない。 Therefore, when the input of the objective lens driving amplifier 3 increases above a predetermined value, the output of the objective lens driving amplifier 3 is rectified and smoothed to increase the gate voltage of the field effect transistor 8. Therefore, the resistance between the drain and source of the field effect transistor 8 is reduced. Therefore, as mentioned above, even if the input signal to the objective lens driving amplifier 3 is several times to several tens of times higher than the input signal during normal image reproduction operation due to random access, the objective lens driving amplifier 3 Since the automatic gain control function works, the objective lens driving amplifier 3 will not be saturated.
また電界効果トランジスタ８のゲートにランダ
ムアクセス指令時に信号を印加するようにして、
ランダムアクセス時のみ対物レンズ駆動用増幅器
３の入力を減衰させるようにしてもよい。 Further, a signal is applied to the gate of the field effect transistor 8 at the time of random access command,
The input of the objective lens driving amplifier 3 may be attenuated only during random access.
以上説明した如く本考案によればフオーカスサ
ーボ装置を構成する対物レンズ駆動用増幅器に利
得制御回路を設けたことにより対物レンズ駆動用
増幅器は飽和することはなく、フオーカスサーボ
装置は安定となり、対物レンズのオフセツトは小
さくなり、ランダムアクセスに必要なフレーム番
号の読取りが不可能となることがないと共に、ラ
ンダムアクセス時に利得制御回路を制御するよう
にした結果、トラツキング成分によつて生ずるノ
イズを防ぐこともできる等の効果を有するもので
ある。 As explained above, according to the present invention, by providing a gain control circuit in the objective lens driving amplifier constituting the focus servo device, the objective lens driving amplifier does not become saturated, and the focus servo device becomes stable. The offset of the objective lens is small, so it does not become impossible to read the frame number required for random access, and as a result of controlling the gain control circuit during random access, noise caused by tracking components is prevented. It also has the advantage of being able to
図は本考案の一実施例のブロツク図。
１……バツフア増幅器、２……可変抵抗、３…
…対物レンズ駆動用増幅器、６……ダイオード、
８……電界効果トランジスタ。
The figure is a block diagram of one embodiment of the present invention. 1...Buffer amplifier, 2...Variable resistor, 3...
...Objective lens driving amplifier, 6...Diode,
8...Field effect transistor.
Claims (1)
クに垂直な方向に移動させるフオーカスサーボ装
置において、 該フオーカスサーボ装置のフオーカスサーボ用
増幅器に利得制御回路を設け、 ランダムアクセス等のスキヤン指令に基づいて
スキヤンを行なうときに上記利得制御回路の利得
を制御して、対物レンズ駆動用増幅器の出力を制
御するようにしたことを特徴とするフオーカスサ
ーボ装置。[Claim for Utility Model Registration] In a focus servo device that moves an objective lens of an optical disk player in a direction perpendicular to the disk, a gain control circuit is provided in the focus servo amplifier of the focus servo device, and random access is provided. A focus servo device characterized in that when performing a scan based on a scan command such as the above, the gain of the gain control circuit is controlled to control the output of an objective lens driving amplifier.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1980168759U JPS6235149Y2 (en) | 1980-11-27 | 1980-11-27 |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1980168759U JPS6235149Y2 (en) | 1980-11-27 | 1980-11-27 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5791141U JPS5791141U (en) | 1982-06-04 |
| JPS6235149Y2 true JPS6235149Y2 (en) | 1987-09-07 |
Family
ID=29527320
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1980168759U Expired JPS6235149Y2 (en) | 1980-11-27 | 1980-11-27 |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6235149Y2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58128031A (en) * | 1982-01-24 | 1983-07-30 | Sony Corp | Disc reproducer |
| JPS5977638A (en) * | 1982-10-26 | 1984-05-04 | Nippon Gakki Seizo Kk | Controlling device of focus servo in optical type disc reproducing device |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS53110805A (en) * | 1977-03-09 | 1978-09-27 | Matsushita Electric Ind Co Ltd | Optical information recording/reproducing device |
-
1980
- 1980-11-27 JP JP1980168759U patent/JPS6235149Y2/ja not_active Expired
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS53110805A (en) * | 1977-03-09 | 1978-09-27 | Matsushita Electric Ind Co Ltd | Optical information recording/reproducing device |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5791141U (en) | 1982-06-04 |
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