JPH01182978A - Servo circuit for disk player - Google Patents

Servo circuit for disk player

Info

Publication number
JPH01182978A
JPH01182978A JP530788A JP530788A JPH01182978A JP H01182978 A JPH01182978 A JP H01182978A JP 530788 A JP530788 A JP 530788A JP 530788 A JP530788 A JP 530788A JP H01182978 A JPH01182978 A JP H01182978A
Authority
JP
Japan
Prior art keywords
pickup
circuit
error signal
gain
tracking error
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.)
Pending
Application number
JP530788A
Other languages
Japanese (ja)
Inventor
Tsuneharu Tamaya
玉谷 常晴
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sanyo Electric Co Ltd
Original Assignee
Sanyo Electric Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Sanyo Electric Co Ltd filed Critical Sanyo Electric Co Ltd
Priority to JP530788A priority Critical patent/JPH01182978A/en
Publication of JPH01182978A publication Critical patent/JPH01182978A/en
Pending legal-status Critical Current

Links

Landscapes

  • Moving Of The Head To Find And Align With The Track (AREA)
  • Optical Recording Or Reproduction (AREA)

Abstract

PURPOSE:To prevent the generation of the reading errors of a jumping-up and the like even when a vibration is given to a pickup from a driving mechanism by increasing a track following capacity of the pickup with increasing the gain of a servo circuit at the time of a pickup moving. CONSTITUTION:When a motor driving circuit inputting voltage necessary to move the pickup exceeds a reference voltage, the output of a comparison circuit 7 inverts from an H level to an L level and turns off the switching transistors Q1 and Q2 of a focus and tracking gain changing circuits 8 and 9. Consequently, gain values R3 and R6 decided by resistors R1-R6 are increased by cutting off and the response of an objective lens to a focus error signal and a tracking error signal turns to be good. Thus, a reading point is kept on the track and the track can be followed well, even when the vibration generated at the time of an optical pickup 1 moving is given to the objective lens.

Description

【発明の詳細な説明】 (イ)産業上の利用分野 本発明は、コンパクトディスクプレーヤ(以下CDプレ
ーヤと略す)等に用いられるトラッキングサーボ回路、
或いはフォーカシングサーボ回路等のトラック走査のた
めに配されたサーボ回路の改良に関するものである。
Detailed Description of the Invention (a) Industrial Application Field The present invention relates to a tracking servo circuit used in a compact disc player (hereinafter abbreviated as CD player), etc.
Alternatively, the present invention relates to an improvement in a servo circuit arranged for track scanning, such as a focusing servo circuit.

(ロ)従来の技術 CDプレーヤは周知の通りディスクの内周から外周側へ
螺施状に刻まれたピット列(トラック)をトラッキング
サーボの働きで正確にトレースすると同時にディスクの
面振れに対しては、フォーカシングサーボにて常に合焦
状態を保ちながら、記録されたディジタル信号をレーザ
光にて読みとり再生を行っている。又、ディスクの最内
周トラックから最外周トラックまでをトレースする為に
、ピックアップ送り機構を備えている。これは、トラッ
キングエラー信号の内、直流成分を検出しこの電圧を増
鴨してピックアップ送り用モータに印加し、ピックアッ
プを径方向に移動させろものである。
(b) Conventional technology As is well known, a CD player uses a tracking servo to accurately trace pit rows (tracks) carved in a spiral pattern from the inner circumference to the outer circumference of the disk, and at the same time to prevent surface runout of the disk. reads and reproduces recorded digital signals using a laser beam while always keeping the camera in focus using a focusing servo. Additionally, a pickup feed mechanism is provided to trace the disk from the innermost track to the outermost track. This is done by detecting the DC component of the tracking error signal, increasing the voltage, and applying it to the pickup feeding motor to move the pickup in the radial direction.

ところで、ピックアップ移動時には、モータ、減速機構
等により振動が発生し、これが、ピックアップの対物レ
ンズに伝わり、サーボ回路に外乱を与え、このため針飛
び等、種々の読取りエラーが生じていた。減速機構の減
速比を大きく設定する事でモータで発生する振動の伝達
を小さく抑える事は可能であるが、斯様に減速比を大き
くとると、ピックアップを最内周と最外周の間で移動さ
せる場合に時間を多く要し、以ってアクセス時間が長く
なるという問題が生じる。従って、ピックアップに伝わ
る振動を十分に抑える様な減速比とする事は出来ない。
By the way, when the pickup is moved, vibrations are generated by the motor, speed reduction mechanism, etc., which are transmitted to the objective lens of the pickup and cause disturbances to the servo circuit, resulting in various reading errors such as needle skipping. It is possible to reduce the transmission of vibration generated by the motor by setting a large reduction ratio of the reduction mechanism, but if the reduction ratio is set to a large value in this way, the pickup cannot be moved between the innermost and outermost peripheries. A problem arises in that it takes a lot of time to do so, which increases the access time. Therefore, it is not possible to set a reduction ratio that sufficiently suppresses vibrations transmitted to the pickup.

また、サーボ回路のゲインを上げる事によりピックアッ
プのトラック追従能力を増大させ、これにより前記外乱
による影響を小さく抑える事が可能であるが、斯様にサ
ーボゲインを上げるとディスク上のキズや汚れ等にサー
ボ回路が追従してしまい、このためトラックジャンプ等
の誤動作を起こす場合が生じる。この為サーボ回路のゲ
インを常に高めに設定する事は出来ない。
In addition, by increasing the gain of the servo circuit, the track following ability of the pickup can be increased, thereby minimizing the influence of the above-mentioned disturbance, but increasing the servo gain in this way can cause scratches, dirt, etc. on the disk. The servo circuit follows this, which may cause malfunctions such as track jumps. For this reason, the gain of the servo circuit cannot always be set high.

Qウ  発明が解決しようとする課題 本発明はピックアップ移動時においてピックアップ耶動
機構にて生じろ振動により、針飛び等の読取りエラーが
生じる事を防止せんとするものである。
Q. Problems to be Solved by the Invention The present invention aims to prevent reading errors such as needle skipping from occurring due to vibrations generated in the pickup sliding mechanism during pickup movement.

に)課題を解決するための手段 上記課題に鑑み本発明はディスク上条こ螺施状若しくは
同心円状に記録された情報トラックを走査して情報を読
取り再生するディスクプレーヤのサーボ回路であって、
トラッキングエラー信号を作成するトラッキングエラー
信号作成回路と、該トラッキングエラー信号作成回路に
より作成される前記トラッキングエラー信号の直流成分
に基きピックアップをディスクの径方向に移動せしめる
ピックアップ駆動回路と、前記直流成分が所定のレベル
電圧を越えた時、制御信号を出力する比較回路と、該比
較回路から出力される前記制御信号に応答して、前記情
報トラックを正確に走査するべく配されたサーボ回路の
ゲインを増大せしめるゲイン変更回路と備える構成とし
た。
B) Means for Solving the Problems In view of the above problems, the present invention provides a servo circuit for a disk player that reads and reproduces information by scanning information tracks recorded in a spiral pattern or concentric circles on a disk.
a tracking error signal creation circuit that creates a tracking error signal; a pickup drive circuit that moves a pickup in the radial direction of the disk based on a DC component of the tracking error signal created by the tracking error signal creation circuit; a comparator circuit that outputs a control signal when a predetermined level voltage is exceeded; and a gain of a servo circuit arranged to accurately scan the information track in response to the control signal output from the comparator circuit. The structure is equipped with a gain changing circuit to increase the gain.

に)作 用 ピックアップ移動時にサーボ回路のゲインが増大されて
ピックアップのトラック追従能力が増大されるので、ピ
ックアップに駆動機構から振動が加わっても、針飛び等
の読取りエラーが生じない。
2) Function: When the pickup is moved, the gain of the servo circuit is increased and the track following ability of the pickup is increased, so even if vibrations are applied to the pickup from the drive mechanism, reading errors such as needle skipping do not occur.

(へ)実施例 第1図において、光ピツクアップ(1)にて得られた信
号はプリアンプ(2)にて増幅、電圧変換された後トラ
ッキングエラー信号、フォーカスエラー信号及び音楽信
号等のデータを含んだ高周波信号に分けられる。又プリ
アンプ(2)には、レーザーダイオード駆動回路及びレ
ーザ光出力制御回路が含まれている。プリアンプ(2)
で得られたトラッキングエラー信号、フォーカスエラー
信号は夫々のゲイン変更回路(81f91にて適当な電
圧に調整された後、トラッキングコイル及びフォーカス
コイル駆動回路00)α1)に印加され、光ピツクアッ
プ(1)の対物レンズをトラッキング方向及びフォーカ
シング方向に電磁駆動する。読取が進むと、対物レンズ
が徐々にディスク外周方向1に移動され、これに応答し
てトラッキングエラー信号の直流分が徐々に増大する。
(f) Example In Fig. 1, the signal obtained by the optical pickup (1) is amplified and voltage converted by the preamplifier (2), and then contains data such as a tracking error signal, a focus error signal, and a music signal. It can be divided into high frequency signals. The preamplifier (2) also includes a laser diode drive circuit and a laser light output control circuit. Preamplifier (2)
The tracking error signal and focus error signal obtained in the above are applied to the respective gain change circuits (81f91 after being adjusted to appropriate voltages) and then applied to the tracking coil and focus coil drive circuit 00) α1), and then the optical pickup (1) The objective lens is electromagnetically driven in the tracking direction and the focusing direction. As reading progresses, the objective lens is gradually moved in the disk outer circumferential direction 1, and in response, the DC component of the tracking error signal gradually increases.

さらにトラッキングエラー信号は、ローパスフィルター
(4)で直流に変換されモータ駆動回路(5)に印加さ
れる。前述の如くトラッキングエラー信号の直流分が、
徐々に太き(なりモータ(6)に光ピツクアップ(1)
が移動するのに必要なトルクが発生するレベルに達する
と、光ピツクアップ(1)がディスク外周方向に数10
トラック駆動され、対物レンズは光ピツクアップ(1)
に対し中立位置に復帰する。(7)は比較回路で、モー
タ駆動回路に加わる電圧と、ピックアップが移動するの
に必要なモータ駆動回路入力電圧よりわずかに小さく設
定された基準電圧とを比較する。尚、囮はディスクが装
置されたターンテーブルを駆動するスピンドルモータα
Jを制御するスピンドルモータ駆動回路である。
Further, the tracking error signal is converted into direct current by a low-pass filter (4) and applied to a motor drive circuit (5). As mentioned above, the DC component of the tracking error signal is
Gradually thickens (becomes light pickup (1) to motor (6)
When the torque required to move the optical pickup (1) reaches a level that generates enough torque to move the optical pickup (1), the optical pickup (1)
Track driven, objective lens is optical pickup (1)
Returns to neutral position. (7) is a comparison circuit that compares the voltage applied to the motor drive circuit with a reference voltage set slightly smaller than the motor drive circuit input voltage necessary for the pickup to move. The decoy is the spindle motor α that drives the turntable on which the disc is installed.
This is a spindle motor drive circuit that controls J.

而してモータ駆動回路入力電圧(直流分)が基準電圧を
超えると、比較回路(7)の出力がHレベルよりLレベ
ルに反転し、フォーカス及びトラッキングゲイン変更回
路(8)(9)のスイッチングトランジスタ(Ql )
 (Q2 )をOFFする。この為抵抗器R1,R2、
R3及びR4、R5、R6にて決定されていたゲイン値
が、R3及びR6がカットオフされることにより増大し
、以ってフォーカスエラー信号及びトラッキングエラー
信号に対する対物レンズの応答が良好となる。従って光
ピツクアップ(1)移動時に発生する振動が対物レンズ
に加わっても、読取り点がトラックからはずれず、良好
にトラックを追従することができる。
When the motor drive circuit input voltage (DC component) exceeds the reference voltage, the output of the comparator circuit (7) is inverted from the H level to the L level, causing the switching of the focus and tracking gain changing circuits (8) and (9). Transistor (Ql)
(Q2) is turned off. For this reason, resistors R1, R2,
The gain values determined by R3, R4, R5, and R6 are increased by cutting off R3 and R6, thereby improving the response of the objective lens to the focus error signal and tracking error signal. Therefore, even if vibrations generated when the optical pickup (1) moves are applied to the objective lens, the reading point will not deviate from the track, and the track can be followed well.

尚、本発明は上記実施例に限定されず種々変更可能であ
ることは謂うまでもない。
It goes without saying that the present invention is not limited to the above embodiments and can be modified in various ways.

(ト)発明の効果 以上、本発明に依れば、ピックアップ駆動時に生じる振
動がピックアップに印加されても、針飛び等読取りエラ
ーが生じることなく、常に良好な再生動作を実現するこ
とができる。
(g) Effects of the Invention As described above, according to the present invention, even if vibrations generated during pickup drive are applied to the pickup, a good reproduction operation can always be achieved without causing reading errors such as needle skipping.

【図面の簡単な説明】[Brief explanation of the drawing]

第1図は本発明の一実施例を示す回路構成図である。 (1)・・・光ピツクアップ、(4)・・・ローパスフ
ィルター、(5)・・・モータ駆動回路、(7)・・・
比較回路、(8)・・・フォーカスゲイン変更回路、(
9)・・・トラッキングゲイン変更回路、α0)・・・
フォーカスコイル叱動回路、(11)・・・トラッキン
グコイル駆動回路。
FIG. 1 is a circuit configuration diagram showing an embodiment of the present invention. (1)...Optical pickup, (4)...Low pass filter, (5)...Motor drive circuit, (7)...
Comparison circuit, (8)...Focus gain change circuit, (
9)...Tracking gain change circuit, α0)...
Focus coil scolding circuit, (11)...tracking coil drive circuit.

Claims (1)

【特許請求の範囲】[Claims] (1)ディスク上に螺施状若しくは同心円状に記録され
た情報トラックを走査して情報を読取り再生するディス
クプレーヤのサーボ回路であって、トラッキングエラー
信号を作成するトラッキングエラー信号作成回路と、該
トラッキングエラー信号作成回路により作成される前記
トラッキングエラー信号の直流成分に基きピックアップ
をディスクの径方向に移動せしめるピックアップ駆動回
路と、前記直流成分が所定のレベル電圧を越えた時、制
御信号を出力する比較回路と、該比較回路から出力され
る前記制御信号に応答して、サーボ回路のゲインを増大
せしめるゲイン変更回路とを備えたことを特徴とするデ
ィスクプレーヤのサーボ回路。
(1) A servo circuit for a disc player that reads and reproduces information by scanning information tracks recorded in a spiral or concentric pattern on a disc, and includes a tracking error signal creation circuit that creates a tracking error signal; a pickup drive circuit that moves the pickup in the radial direction of the disk based on the DC component of the tracking error signal created by the tracking error signal creation circuit; and a pickup drive circuit that outputs a control signal when the DC component exceeds a predetermined level voltage. A servo circuit for a disc player, comprising: a comparison circuit; and a gain change circuit that increases the gain of the servo circuit in response to the control signal output from the comparison circuit.
JP530788A 1988-01-13 1988-01-13 Servo circuit for disk player Pending JPH01182978A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP530788A JPH01182978A (en) 1988-01-13 1988-01-13 Servo circuit for disk player

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP530788A JPH01182978A (en) 1988-01-13 1988-01-13 Servo circuit for disk player

Publications (1)

Publication Number Publication Date
JPH01182978A true JPH01182978A (en) 1989-07-20

Family

ID=11607621

Family Applications (1)

Application Number Title Priority Date Filing Date
JP530788A Pending JPH01182978A (en) 1988-01-13 1988-01-13 Servo circuit for disk player

Country Status (1)

Country Link
JP (1) JPH01182978A (en)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5934853A (en) * 1982-08-20 1984-02-25 Horiuchi Itarou Shoten:Kk Food additive
JPS61188788A (en) * 1985-02-18 1986-08-22 Matsushita Electric Ind Co Ltd Recorded information reproduction device

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5934853A (en) * 1982-08-20 1984-02-25 Horiuchi Itarou Shoten:Kk Food additive
JPS61188788A (en) * 1985-02-18 1986-08-22 Matsushita Electric Ind Co Ltd Recorded information reproduction device

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