JPS6050634A - Optical disc device - Google Patents
Optical disc deviceInfo
- Publication number
- JPS6050634A JPS6050634A JP15626483A JP15626483A JPS6050634A JP S6050634 A JPS6050634 A JP S6050634A JP 15626483 A JP15626483 A JP 15626483A JP 15626483 A JP15626483 A JP 15626483A JP S6050634 A JPS6050634 A JP S6050634A
- Authority
- JP
- Japan
- Prior art keywords
- objective lens
- base material
- optical disc
- recording surface
- disc base
- 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
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
- G11B7/085—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam into, or out of, its operative position or across tracks, otherwise than during the transducing operation, e.g. for adjustment or preliminary positioning or track change or selection
- G11B7/08547—Arrangements for positioning the light beam only without moving the head, e.g. using static electro-optical elements
Landscapes
- Automatic Focus Adjustment (AREA)
- Optical Recording Or Reproduction (AREA)
Abstract
Description
【発明の詳細な説明】
〔発明の利用分野〕
本発明は、光学的に情報を記録または再生する元ディス
ク装置に係抄、特に対物レンズの自動焦点制御引込動作
時の誤動作防止に好適な対物レンズ移動可能領域の設定
に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a source disk device that optically records or reproduces information, and in particular to an objective lens suitable for preventing malfunction during automatic focus control retraction operation of an objective lens. Concerning setting of lens movable area.
光学的に情報を記録または再生を行なう元ディスク装置
の記録媒体（以下、光ディスクと呼ぶ）は、第１図に示
すように、ガラスまたはＰＭＭＡ等を基材１１に使用し
、その表面に例えばテルル系金属等からなる膜１２を薄
く蒸着した構造となっている。この場合、金属膜の酸化
等による記録面１３の侍卸劣化を防＋ｈするために、第
２図に示すよ５１Ｃ１記録面を内側にして２枚の基材を
スペーサ２３．２４を介して貼５．６わせ、サンドウィ
ッチ構造にすること、および第３図に示すように金属膜
１２の表面に直接アクリル等の保護膜を設けた構造が知
られている。従つ−０１元ディスクにおいて金属膜に情
報を記録または再生するだめには、基材１１を通過した
元スポットが金属膜と照射されることになる。As shown in FIG. 1, the recording medium (hereinafter referred to as an optical disk) of a source disk device that optically records or reproduces information uses a base material 11 made of glass or PMMA, and has a surface coated with tellurium, for example. It has a structure in which a film 12 made of a metal or the like is thinly deposited. In this case, in order to prevent deterioration of the recording surface 13 due to oxidation of the metal film, etc., two base materials are pasted together with the 51C1 recording surface inside with spacers 23 and 24 in between, as shown in FIG. 5.6, a sandwich structure is known, and a structure in which a protective film such as acrylic film is directly provided on the surface of the metal film 12 as shown in FIG. 3 is known. Therefore, in order to record or reproduce information on a metal film in a -01 original disk, the original spot that has passed through the base material 11 is irradiated with the metal film.
上記光スポットは、例えば第４図に示すような光学装置
を使って形成される。直線偏光を発する半導体レーザ４
１から照射された光束は、コリメータレンズ４２、調光
ビームスプリッタ４３４分の１波長板４４を経由し、対
物レンズ４５で集束させて元スポットを形成する。半導
体レーザ４１の波長が８３００ｎｍＯ時は対物レンズ４
５の開口数０．５とすると元スポット径はおおよそ１．
６μＩｎとなる。The light spot is formed using an optical device as shown in FIG. 4, for example. Semiconductor laser 4 that emits linearly polarized light
The light beam irradiated from 1 passes through a collimator lens 42, a dimming beam splitter 43, and a 1/4 wavelength plate 44, and is focused by an objective lens 45 to form an original spot. When the wavelength of the semiconductor laser 41 is 8300 nmO, the objective lens 4
5 and the numerical aperture is 0.5, the original spot diameter is approximately 1.5.
It becomes 6μIn.
記録膜からの元スポットのズレを検出する方式は既に多
くの提案がちシ秋の１例として、希４図は非点収差方式
における光学部品の配置を示す。記録面１３で反射され
た光束は、第３図の対物レンズ４５．４分の１波長板４
４を通過して、偏光ビームスプリッタ４３で直角方向に
向きを変え、凸レンズ４６、円柱し／ズ４７を通過して
光電変換素子４日に到達する。光電変換素子４日は、第
５図に示すよう［５１，５２，５３，５４に分割してあ
り、受光素子５１と５２の出力の和と、受光素子５３と
５４の出力の和とを差動増゛幅器５５に入力し、その差
信号で焦点ズレを検出する。Many methods have already been proposed for detecting the deviation of the original spot from the recording film.As an example, Figure 4 shows the arrangement of optical components in the astigmatism method. The light beam reflected by the recording surface 13 is passed through the objective lens 45 and the quarter-wave plate 4 shown in FIG.
4, changes direction at a right angle by a polarizing beam splitter 43, passes through a convex lens 46 and a cylindrical lens 47, and reaches a photoelectric conversion element 4. The photoelectric conversion element 4 is divided into 51, 52, 53, and 54 as shown in FIG. The signal is input to a dynamic amplifier 55, and the difference signal is used to detect a focal shift.
ディスクの回転に伴なって記録面１′５の位置が゛変動
すると、反射光束の集束位置が移動する。When the position of the recording surface 1'5 changes as the disk rotates, the focal position of the reflected light beam moves.
この集束位置の移動は、第４図に示した円柱レンズ４７
で形状の変化に変換される。記録面への入射うｔが該記
録面上に集 束しているときけ、光電変換素子４８上の
反射光は、遺５図（ｂ）に点線で示した如く円形になシ
、各受光素子５１〜５４に均等に照射されるだめ、等動
増幅器５５の出力はゼロである。入射光が前記記録面の
後方で集束するとき、すなわち、対物レンズ４５と記録
面１２との間の距離が短いときは、反射光は光電変換素
子４８上で第６図ＩＣ）に示しだように。This movement of the focusing position is performed by the cylindrical lens 47 shown in FIG.
is converted into a change in shape. When the incident light on the recording surface is focused on the recording surface, the reflected light on the photoelectric conversion element 48 becomes circular as shown by the dotted line in Figure 5(b), and each received light beam is Since the elements 51 to 54 are uniformly irradiated, the output of the equal-motion amplifier 55 is zero. When the incident light is focused behind the recording surface, that is, when the distance between the objective lens 45 and the recording surface 12 is short, the reflected light is reflected on the photoelectric conversion element 48 as shown in FIG. 6 IC). To.
横長の形状になシ、差動増幅器５５の出力は正側１に増
大する。逆に、入射光が記録面１２の前方で集束すると
き、すなわち、対物レンズ４５と前記記録面１２との距
離が大きいときＫけ、光電変換素子４８上の反射光は、
第６図（ｄ）に点線で示した如く縦長の形状となり、差
動増幅器４８の出力ば。Without the horizontally elongated shape, the output of the differential amplifier 55 increases to the positive side. Conversely, when the incident light is focused in front of the recording surface 12, that is, when the distance between the objective lens 45 and the recording surface 12 is large, the reflected light on the photoelectric conversion element 48 is:
The output of the differential amplifier 48 has a vertically elongated shape as shown by the dotted line in FIG. 6(d).
負側に増大する。increases on the negative side.
そとで対物レンズ４５と、記録媒体すなわち記。On the other side is an objective lens 45 and a recording medium.
録画との距離に対応して差動増幅器５５の出力は第６図
（ｅ）に示すような８字特性を示すようになる。The output of the differential amplifier 55 exhibits a figure 8 characteristic as shown in FIG. 6(e) in accordance with the distance from the recording.
一方、対物レンズ４５は、磁界中に配設された２フオー
カスアクチヱエータコイル５７（以下単に。On the other hand, the objective lens 45 includes a two-focus actuator coil 57 (hereinafter simply referred to as simply) arranged in a magnetic field.
コイル５７と記す）に生ずる電磁力で駆動され、。It is driven by an electromagnetic force generated in a coil 57).
その位置はコイル５７に流す電流によって制＃さ。Its position is controlled by the current flowing through the coil 57.
れる。そとで差動増幅器５５の出力画号を増幅器。It will be done. On the other hand, the output image signal of the differential amplifier 55 is amplified.
５６で増幅してコイル５７に出力し、対物レンズ４５の
位置を制御して自動焦点動作を行なうことができる。56 and output to a coil 57, the position of the objective lens 45 can be controlled to perform automatic focusing operation.
然るに、光ディスクからの信号読取シ開始前は、光ディ
スクの装着などの都合により、対物レンズ４５の位置を
光ディスクから可能な限シ陥れた位置に置くのが普通で
ある。この状°態から上述したフォーカス制御系を動作
させ、対物レンズ４５の位置を糧適位、１に制御する局
舎、対物レンズ４５の初期位置では差動増幅器５６の出
力信号が第６図（ｅ）に示した８字特性の非線形部分に
ある。つまり、フォーカス制御系の制御動作範囲外にあ
るため、回路全体のスイッチオンと同時に対物レンズ４
５の位置制御を庁なうことは困難である。However, before starting to read signals from the optical disk, the objective lens 45 is usually placed at a position as far away from the optical disk as possible due to reasons such as mounting the optical disk. From this state, the focus control system described above is operated, and the position of the objective lens 45 is controlled to the appropriate position, 1. At the initial position of the objective lens 45, the output signal of the differential amplifier 56 is as shown in FIG. It is in the nonlinear part of the figure 8 characteristic shown in e). In other words, since it is outside the control operation range of the focus control system, the objective lens 4 is turned on at the same time as the entire circuit is turned on.
It is difficult to manage the position control of 5.
そこで、通常は元ディスク面から離れた位置から対′吻
しンズ４５を強制的に光デイスク面の方向に移動し、対
物レンズをフォーカス制御系の制御範囲内に引き込むよ
うにしている。Therefore, normally, the objective lens 45 is forcibly moved toward the optical disk surface from a position away from the original disk surface to draw the objective lens within the control range of the focus control system.
しかしながら、前記した如く、対物し／ズ４５）を光デ
ィスクから充分例離した位置から移動開始すると、本来
の記録面近傍におけ乙位置ズレを示す８字特性を得る前
（（、元ディスクの基材面あるいは記録面の保護膜面か
らの反射による８字特性が現われるため、対物レンズが
記録面以外の位置に誤って自動焦点されてしまう欠点が
ある。However, as mentioned above, if the objective lens 45) starts moving from a position sufficiently far away from the optical disc, the character 8 characteristic ((, the original disc's original Since the figure-8 characteristic appears due to reflection from the material surface or the protective film surface of the recording surface, there is a drawback that the objective lens is erroneously automatically focused on a position other than the recording surface.
本発明の目的は、上述しプこ誤った自、幼魚点動作を回
避できる）′ｔ、ディスク装置を提供することにある。SUMMARY OF THE INVENTION An object of the present invention is to provide a disk device that can avoid the above-mentioned erroneous and juvenile point operation.
上記目的を達成するため、本発明で（は自動焦点への引
込み時に対物レンズ４５の焦点立置が元ディスク基材面
を横切らないように、対物しンズ４５の＃動町紺範囲を
、元ディスク基材厚さ・との関連から規定したものであ
る。すなわち、本発明では、退避時における対物レンズ
の焦点位置がｙ６デイスク基材内に有るよｒ）ＶＣｓ対
物レンズの８動を制限するストッパを設けたことを特徴
とする。In order to achieve the above object, in the present invention (in order to prevent the focal position of the objective lens 45 from crossing the original disk substrate surface when retracting to automatic focusing), the # moving town dark blue range of the objective lens 45 is This is defined in relation to the thickness of the disk base material.In other words, in the present invention, the focal position of the objective lens at the time of retraction is within the y6 disk base material. It is characterized by a stopper.
以下、本発明の一実施例をフォーカシングアクチュエー
タと光ディスクの模式図であるＭ６図（ａ）、（ｂ）に
よシ説明する。図において、１１は殆）ディスク基材、
１２は記録膜である。An embodiment of the present invention will be described below with reference to FIGS. M6 (a) and (b), which are schematic diagrams of a focusing actuator and an optical disc. In the figure, 11 is mostly the disk base material;
12 is a recording film.
また、６１は対物し／ズ４５の下限の位置を決定するス
トッパ、６２はレンズ４５の上限の位置を決定するスト
ッパでちる。図（ａ）は、記録面１２・に前記対・酸レ
ンズ４５の焦点位１面が一致した状態を示し、対物レン
ゼ移動可能範囲の中央に位Ｉ］ｔシ、図（ｂ）は対Ｉ吻
しンズ４５が下坂まで下がった状態を示す。例えば基材
１１に１．２Ｍ厚のガラスを使用し、対物レンズ４５の
上下移動量を仮１ｃ１．２＋ａ＋の半分の０．６困とし
た局舎、図示しない元ディスク取付面と前記対物レンズ
の下限を決めるストッパ６１の位置誤差を考慮しても、
対物レンズ４５の焦点位置は前記したフォーカス・制御
のための引込み動作時に元ディスクの慎材１１７３λら
外には出ることがない。Further, 61 is a stopper that determines the lower limit position of the objective lens 45, and 62 is a stopper that determines the upper limit position of the lens 45. Figure (a) shows a state where one focal point of the anti-acid lens 45 coincides with the recording surface 12, and the center of the movable range of the objective lens is located at the center of the objective lens movable range. It shows a state in which the nose tines 45 have descended to a downward slope. For example, in a case where 1.2M thick glass is used for the base material 11 and the vertical movement amount of the objective lens 45 is set to 0.6, which is half of 1c1.2+a+, the distance between the original disk mounting surface (not shown) and the objective lens is Even considering the positional error of the stopper 61 that determines the lower limit,
The focal position of the objective lens 45 does not go beyond the blank 1173λ of the original disk during the retracting operation for focus and control described above.
本発明によれば、光デイスク基材の記録面と反対側の［
７を検出することがないので差動増幅器は真の３１シ録
面かむ得られる８字特性のみを出力する。従って、対物
レンズの焦点位置が記録面以外の面に設定されるのを防
止できる効果がある。According to the present invention, [
Since there is no detection of 7, the differential amplifier outputs only the 8-character characteristic obtained from the true 31-frame recording surface. Therefore, it is possible to prevent the focal position of the objective lens from being set on a surface other than the recording surface.
である。It is.
１１ ・・光デイスク基材
１２ ・・記録膜 １３・・記録面
４５・・・対物レンズ ４８・・光電変換素子５５・・
差動増幅器
６１．６２ ・・ストッパ
６３．６４ ・・レンズの弾性支持体
第 １虐 第２虐
９３
ノ！
躬４−囚
第５０
第 ６１１Ｄ
市−７
第ワロ11... Optical disk base material 12... Recording film 13... Recording surface 45... Objective lens 48... Photoelectric conversion element 55...
Differential amplifier 61.62 ... Stopper 63.64 ... Lens elastic support Part 1 Part 2 Part 93 No! 4th Prisoner 50th 611D City-7th Waro
Claims (1)
物レンズを有し、前記対物レンズと前記情報記録面との
間の距離を制御して前記対物レンズへの入射光束を前記
情報記録面上に集束させるフォーカス制御手段を有する
光デイスク装置において、前記対物レンズの移動可能距
離が、前記記録媒体の基材厚さの２倍よりも小さくなる
ように前記対物レンズの移動可能範囲を規定するストッ
パを設けたことを特徴とする元ディスク装置。The objective lens is provided movably in a direction perpendicular to the information recording surface of the recording medium, and the distance between the objective lens and the information recording surface is controlled to direct the light beam incident on the objective lens to the information recording surface. In an optical disk device having a focus control means for upward focusing, the movable range of the objective lens is defined such that the movable distance of the objective lens is less than twice the thickness of the base material of the recording medium. A former disk device characterized by being provided with a stopper.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15626483A JPS6050634A (en) | 1983-08-29 | 1983-08-29 | Optical disc device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15626483A JPS6050634A (en) | 1983-08-29 | 1983-08-29 | Optical disc device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS6050634A true JPS6050634A (en) | 1985-03-20 |
Family
ID=15624001
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP15626483A Pending JPS6050634A (en) | 1983-08-29 | 1983-08-29 | Optical disc device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6050634A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6423428A (en) * | 1987-07-20 | 1989-01-26 | Mitsubishi Electric Corp | Recording medium driver and focus tracking device in recording medium driver |
| JPH02149115U (en) * | 1989-05-18 | 1990-12-19 | ||
| JPH0689449A (en) * | 1992-09-07 | 1994-03-29 | Sharp Corp | Driving device for objective lens |
-
1983
- 1983-08-29 JP JP15626483A patent/JPS6050634A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6423428A (en) * | 1987-07-20 | 1989-01-26 | Mitsubishi Electric Corp | Recording medium driver and focus tracking device in recording medium driver |
| JPH0565936B2 (en) * | 1987-07-20 | 1993-09-20 | Mitsubishi Electric Corp | |
| JPH02149115U (en) * | 1989-05-18 | 1990-12-19 | ||
| JPH0689449A (en) * | 1992-09-07 | 1994-03-29 | Sharp Corp | Driving device for objective lens |
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