JPS6093644A - Detecting method of optical focus - Google Patents
Detecting method of optical focusInfo
- Publication number
- JPS6093644A JPS6093644A JP20120383A JP20120383A JPS6093644A JP S6093644 A JPS6093644 A JP S6093644A JP 20120383 A JP20120383 A JP 20120383A JP 20120383 A JP20120383 A JP 20120383A JP S6093644 A JPS6093644 A JP S6093644A
- Authority
- JP
- Japan
- Prior art keywords
- light
- photoelectric conversion
- objective lens
- optical axis
- conversion element
- 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
- G11B7/09—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
- G11B7/0908—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 for focusing only
Landscapes
- Optical Recording Or Reproduction (AREA)
- Automatic Focus Adjustment (AREA)
Abstract
Description
【発明の詳細な説明】
この発明は、円板状の情報記録媒体に収録された記録の
読み取シ方法として光学的手段による装置で、読み取勺
商所に集光するように照射する光の自動焦点検出方法に
関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention is an apparatus using optical means as a method for reading records recorded on a disk-shaped information recording medium, and an automatic method of emitting light so as to converge it on a reading area. This invention relates to a focus detection method.
円板状の情報記録媒体は「７Ｊイスク」と称され、（本
発明においても以下ディスクと称す）その版面には周波
数変調あるいは符号変調された信号を概ね多種の異形微
細突起（約０．７μｍｘ０．６．ｃｕｔｓないし４μｒ
ｑ Ｘ Ｏ，Ｉ Ａｍ ）をもって顕し、該微細突起を
線状に直列し更にこれを螺旋状にし１且つ１相隣るトラ
ックとの間隙が約２μｍ程度で収録しである。The disc-shaped information recording medium is called a "7J disk" (hereinafter referred to as a disk in the present invention), and its plate surface has various irregularly shaped microprotrusions (approximately 0.7 μm x 0 .6.cuts or 4μr
q X O, I Am ), and the fine protrusions are linearly arranged in series, and further spirally formed, with a gap of about 2 μm between adjacent tracks.
このような状態をもって収録されたものに対し、読み取
シ手段の一つとして、レーザー光線を用い）且つ１該レ
ーデ−光線を集光して前記各々の微細突起を照射し、そ
の反射光を読み取り検出された信号を情報に再生するも
のである。For things recorded in such a state, a laser beam is used as one of the reading means) and 1. The laser beam is focused and irradiated onto each of the above-mentioned microscopic protrusions, and the reflected light is read and detected. The signal is then regenerated into information.
しかしながら、ディスクの回転に伴う歪動によって照光
する焦点が記録媒体上よシ外れる不安定な状態が常時発
生し、そのため正確な情報再生効果が得ることができず
、従って、ディスクの歪動に追随してレーザー光線を透
過させる対物レンズを自動的に光軸方向に移動させて記
録媒体上には常に集光状態を維持させる手段が主流とな
っている。この対物レンズを移動させる運動の情報源と
して反射光の一部を偏光プリズムによって採取し、合焦
・不合焦状態を検知し、該状態に応じて対物レンズの移
動運動手段に信号を付与する基本的な方法は既に公知で
、偏光グリズムによって得る反射光の検知方法について
様々な開発がなされている。However, due to the distortion caused by the rotation of the disk, an unstable state occurs that causes the illumination focus to be off the recording medium, making it impossible to obtain an accurate information reproduction effect. The mainstream method is to automatically move an objective lens that transmits a laser beam in the optical axis direction so that the laser beam is always focused on the recording medium. A part of the reflected light is collected by a polarizing prism as an information source for the movement of the objective lens, and the in-focus/out-of-focus state is detected, and a signal is given to the movement means of the objective lens according to the state. This method is already known, and various developments have been made regarding methods for detecting reflected light obtained by polarizing grisms.
この発明は、上記の検知方法において、偏光プリズムに
より得られた合焦または不合焦の光束を検知する焦点検
出方法に係るものである。The present invention relates to a focus detection method for detecting a focused or unfocused light beam obtained by a polarizing prism in the above detection method.
この発明は、光源から放射された光を対物レンズによシ
被照射物体に集束させ、その反射光の少なくともその一
部を該反射光の光軸と同心円上に複数に分割された光電
変換素子に導き、各々の光電変換素子上の前記反射光の
光蓋分布を検出することによシ、前記対物レンズの前記
被照射物体に対する焦点誤差を得る焦点検出方法でおる
。This invention focuses light emitted from a light source onto an irradiated object using an objective lens, and at least a part of the reflected light is divided into a plurality of photoelectric conversion elements concentrically with the optical axis of the reflected light. In this focus detection method, the focus error of the objective lens with respect to the irradiated object is obtained by detecting the optical cover distribution of the reflected light on each photoelectric conversion element.
次に、この発明の実施例を図面とともに説明すれば、＃
！１図は、レーデ−光線によｔｙイスクよシ信号を検出
する原理を説明するもので、レーデ−ダイオード（１）
から拡幅された光はコリメートレンズ（２）で束ねられ
、その光を偏光プリズム（３）ならびに１／４波長板（
４）を通過させ、更に対物レンズ（５）で集光させ、デ
ィスク（６）の狭面を照射する。ｆ４らびに１／４波長
板（４）を透過し、偏光プリズム（３）の反射面（３つ
で反射した光をディテクターレン、ｔ” （７）を通過
させて集光した光束を、その光軸上である設定距離を介
した位置に該光軸を中心とする同心円状に複数に分割さ
れた光電変換素子（８ンを設置して成るものである。Next, an embodiment of this invention will be described with reference to the drawings.#
! Figure 1 explains the principle of detecting optical signals using a radar beam.
The light beams expanded from
4) and is further focused by an objective lens (5) to illuminate the narrow surface of the disk (6). The light beam transmitted through f4 and the quarter-wave plate (4), and reflected by the three reflecting surfaces of the polarizing prism (3) is passed through the detector lens, t'' (7), and the condensed light beam is It consists of a photoelectric conversion element (8 units) that is divided into a plurality of concentric circles centered on the optical axis at positions at a predetermined distance on the optical axis.
使用する光電変換素子（８）について説明すれば、その
構造を半導体としたものでも、光導電セル、７オト・ダ
イオード、フォト・トランゾスタ、７オト・ダイオード
リニアアレイ、フォト・ダイオードエリアアレイ等が存
在し、上記の種類中、この発明の目的ならび作用に適す
るものがフォト・ダイオードで、そのフォト・メイオー
ド種の中でもＰＩＮ ７オト・ダイオードが最適と考え
られる。To explain the photoelectric conversion elements (8) used, even if the structure is semiconductor, there are photoconductive cells, 7-oto diodes, photo-transostors, 7-oto-diode linear arrays, photodiode area arrays, etc. However, among the above-mentioned types, the photodiode is suitable for the purpose and operation of the present invention, and among the photomeiode types, the PIN 7 autodiode is considered to be the most suitable.
フォト・ダイオードは、半導体のＰＮ接合部に光が当た
るときに生ずる光起電力効果を利用した素子で１負荷抵
抗を通してＰＮ接合に逆電圧をかけて使い、光の強さに
比例する底流変化を取シ出すもので、その感度は０．４
５Ａ／Ｗ程度で、応答速度は５ないし１０μＢ、分光感
度は紫外から近赤外までの種々な素子がお９、なかでも
接合部をＰＩＮ構造にしたいわゆるＰＩＮ ７オト・ダ
イオードは接合容量が小さく、高速応答が可能で、その
速度は１ないしｌ Ｏ＃８のものが得られ、１１１１１
１１１１１１１１１入射光−■―に比例した出力−が得
られるものである。A photodiode is a device that utilizes the photovoltaic effect that occurs when light hits the PN junction of a semiconductor.It is used by applying a reverse voltage to the PN junction through a load resistor, and produces an undercurrent change that is proportional to the intensity of the light. The sensitivity is 0.4.
There are various devices with a power output of about 5 A/W, a response speed of 5 to 10 μB, and a spectral sensitivity ranging from ultraviolet to near-infrared. Among them, the so-called PIN 7 auto diode, which has a PIN structure at the junction, has a small junction capacitance. , high-speed response is possible, and the speed is 1 to l O#8 can be obtained, 11111
111111111 An output proportional to the incident light -■- can be obtained.
以上のように、フォト・ダイオードならびにＰＩＮフォ
ト・ダイオードの特質の一つである高速応答効果も充電
変換素子（８）に要求する大切な要素の一つである。As described above, the high-speed response effect, which is one of the characteristics of photodiodes and PIN photodiodes, is also one of the important elements required of the charging conversion element (8).
次に、ディスク（６ンの表面が、対物レンズ（５）の焦
点位置にある場合と、該焦点位置以外の位置にある場合
の反射光の状態について説明すれば、対物レンゼ（５）
に対し、平行して入射し、且つ、集光してｙ”イスク（
６）表面に焦合させるものであるが、歪動するディスク
（６）の位置によって、焦合あるいは非焦合に度化し、
従って、ディスク（６）の表面位置によって反射される
光束は第２図示の如くグイチクターレンズ（７）の光軸
上に数多の焦点位置が形成される。第２図示はｆ”イス
ク（６ンの表面位置が対物レンズ（５）の焦点と合焦状
態にある場合の光束を実線で示し、７’ ４チクターレ
ンズ（７）の光軸における（１）場で合焦し、対物レン
ズ（５）の焦点距離（ロ）以外の１例として焦点距離■
よシも遠い（ＬＸ）位置にディスク（６）がある場合の
光束を２点鎖線で示すごとく１対物レンズ（５）の焦点
距離■以外の位置にｆ”イスク（６）の表面が存在する
場合にはディテクターレンズ（７）の光軸で前記（１）
場以外の異った位置の（ＩＩ）場に合焦する。Next, we will explain the state of reflected light when the surface of the disk (6) is at the focal position of the objective lens (5) and when it is at a position other than the focal position of the objective lens (5).
The light is incident parallel to the y” isk (
6) It focuses on the surface, but depending on the position of the distorted disk (6), it becomes focused or defocused,
Therefore, the light beam reflected by the surface position of the disk (6) forms many focal points on the optical axis of the directional lens (7) as shown in the second figure. The second illustration shows the light flux when the surface position of the f'' isk (6) is in focus with the focal point of the objective lens (5), and the (1) field at the optical axis of the 7' 4 chictor lens (7). In addition to the focal length (b) of the objective lens (5), the focal length ■
The surface of the f'' disk (6) exists at a position other than the focal length of the first objective lens (5), as shown by the two-dot chain line, which shows the light flux when the disk (6) is located at a very far (LX) position. In this case, the optical axis of the detector lens (7) is
(II) field at a different position other than the field.
そこで、前記、７’ ４チクターレンズ（７）の光軸に
おける合焦位置（Ｉ）場およびω）場とは直接関連のな
い任意設定したＱＱ）場に光電変換素子（８ンを設置す
るＯこの光電変換素子（８）は前記のように光軸を中心
とした同心状に複数に分割したものを用いる。すなわち
、光軸を中心としたある半径（１）の中心光１＆換素子
（８ａ）と、この中心光１＆換素子（８ａ）が嵌合でき
る中心孔を有する外側光電震換累子（８ｂ）とに２分割
し、且つ双方を面一状態に構成するものである。（第３
図参照〕
なお、前記外側光電変換素子（８ｂ）を環状に形成し更
にその外側に別個の九′亀笈換素子の環状体あるいは更
に小さく細分割してよシ緻密な光分布の受光作用を得る
ことができるようにしても任意である。Therefore, a photoelectric conversion element (8) is installed at the focal position on the optical axis of the 7'4 Tictor lens (7) at an arbitrarily set QQ) field that is not directly related to the (I) field and the ω) field. The photoelectric conversion element (8) is divided into a plurality of parts concentrically with the optical axis as the center as described above.In other words, the central light 1 and the conversion element (8a) with a certain radius (1) centered on the optical axis are used. and an outer photoelectric conversion converter (8b) having a center hole into which the center light 1 & converter element (8a) can fit, and both are arranged flush. (Third
[See figure] Note that the outer photoelectric conversion element (8b) is formed into a ring shape, and a separate ring-shaped 9'tortoise conversion element is formed on the outside thereof, or it is further subdivided into smaller pieces to achieve a light-receiving function with a dense light distribution. Even if it is possible to obtain it, it is optional.
この発明は以上のように、ディスク（６）で反射した光
束の少なくともその一部を最終的にｆ４チクｐ −Ｌ／
ンズ（７）よシ取シ出し、該ｒイテクターレンズ（７）
の光軸にある設定した距離を介して光軸を中心としたあ
る半径（ｒ）の中心光篭袈換素子（８ａ）と、該中心光
電変換素子（８ａ）の外周に外側光電変換素子（８ｂ）
とを面一状に形成した光電変換素子（８）を設け、前記
ディテクターレンズ（７）を通過した反射光の焦点距離
の差によって光電変換素子（８）における受光光束の半
径が笈化し、これを中心光電変換素子（８ａ）と外側光
電変換素子（８りとの受光量ならびに受光力に応じたそ
れぞれ異なる出力の差異によって対物レンズ（５）とデ
ィスク（６ンとの合焦、非合焦の度合を検出するもので
ある。As described above, in this invention, at least a part of the light beam reflected by the disk (6) is finally
Take out the lens (7) and take out the r protector lens (7).
A central light basket switching element (8a) with a certain radius (r) centered on the optical axis is located at a set distance from the optical axis of the lens, and an outer photoelectric conversion element ( 8b)
A photoelectric conversion element (8) is provided which is formed flush with the detector lens (7), and the radius of the received light beam at the photoelectric conversion element (8) is changed due to the difference in the focal length of the reflected light that has passed through the detector lens (7). The objective lens (5) and the disk (6) are brought into focus and out of focus by the difference in the amount of light received by the center photoelectric conversion element (8a) and the outer photoelectric conversion element (8a), as well as the different outputs depending on the light reception power. This is to detect the degree of
以上のようにこの発明は、光電変換素子（８）を反射光
の焦点以外の位置に設置するものであるから、該光′電
変換素子（８ンの設置にめた〕取シ付は精度を要すこと
なく容易に取り付けられる０この光電変換素子（８）に
よって対物レンズ（５）のｆ４スク（６ンに対する焦点
誤差が大であっても適確な信号を得ることができる。As described above, in this invention, since the photoelectric conversion element (8) is installed at a position other than the focal point of the reflected light, the mounting accuracy is required for the installation of the photoelectric conversion element (8). This photoelectric conversion element (8), which can be easily attached without requiring a lens, makes it possible to obtain an accurate signal even if the focus error with respect to the f4 screen (6 lens) of the objective lens (5) is large.
このようにして少ない部品点数にょシ適確な信号ｆ：得
られると共に構成が簡素なため光学的調整が容易な効果
を有するものである。In this way, an accurate signal f can be obtained with a small number of parts, and the structure is simple, making optical adjustment easy.
また、従前の合焦度合検出装置においては、１イテクタ
ーレンズより発せられる光束受光の光学的装置は機構的
にも大型となシ、狭い空所に挿装し戚い欠点がありたが
、本発明の合焦度合検出手段に用いられる光電変換素子
自体が薄型で、且つ、小型であり、特に装置箇所の任意
性にょシ、その収納容積を微小化することができる効果
あることを％徴とするものである。In addition, in the conventional focusing degree detection device, the optical device for receiving the light beam emitted from the single taketer lens was mechanically large and had the disadvantage of being inserted into a narrow space. The photoelectric conversion element itself used in the focusing degree detection means of the present invention is thin and small, and is particularly effective in reducing the storage volume of the device, since the location of the device is optional. That is.
第１図はレーデ−光線によシｆ４スクより信号を検出す
る原理の説明図、第２図は合焦・非合焦の説明図、第３
図は光電変換素子の正面図である。
（１）・・・レーデ−ダイオード、（５）・・・対物レ
ンズ、（６）・・・ディスク、（８）・・・光電変換素
子。
特許出願人
広重産業株式会社Figure 1 is an explanatory diagram of the principle of detecting a signal from the f4 disk using a radar beam, Figure 2 is an explanatory diagram of focusing and defocusing, and Figure 3
The figure is a front view of a photoelectric conversion element. (1)... Radical diode, (5)... Objective lens, (6)... Disc, (8)... Photoelectric conversion element. Patent applicant Hiroshige Sangyo Co., Ltd.
Claims (1)
県東させ、その反射光の少なくとも一部を該反射光の光
軸と同心円状に複数に分割された光電変換素子に導き、
各々の光篭菱換素子上の前記反射光の光量分布を検出す
ることによシ、前記対物レンズの前記被照射物体に対す
る焦点誤差信号を得る光学的焦点検出方法。Directing the light emitted from the light source to the irradiated object using an objective lens, and guiding at least a portion of the reflected light to a photoelectric conversion element divided into a plurality of parts concentrically with the optical axis of the reflected light,
An optical focus detection method that obtains a focus error signal of the objective lens with respect to the irradiated object by detecting the light amount distribution of the reflected light on each light beam conversion element.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20120383A JPS6093644A (en) | 1983-10-27 | 1983-10-27 | Detecting method of optical focus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20120383A JPS6093644A (en) | 1983-10-27 | 1983-10-27 | Detecting method of optical focus |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS6093644A true JPS6093644A (en) | 1985-05-25 |
Family
ID=16437053
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP20120383A Pending JPS6093644A (en) | 1983-10-27 | 1983-10-27 | Detecting method of optical focus |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6093644A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0268357A2 (en) * | 1986-09-20 | 1988-05-25 | Fujitsu Limited | Optical system with grating lens assembly |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS53100203A (en) * | 1977-02-15 | 1978-09-01 | Mitsubishi Electric Corp | Optical reproducer |
-
1983
- 1983-10-27 JP JP20120383A patent/JPS6093644A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS53100203A (en) * | 1977-02-15 | 1978-09-01 | Mitsubishi Electric Corp | Optical reproducer |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0268357A2 (en) * | 1986-09-20 | 1988-05-25 | Fujitsu Limited | Optical system with grating lens assembly |
| US4832464A (en) * | 1986-09-20 | 1989-05-23 | Fujitsu Limited | Optical system with grating lens assembly for correcting wavelength aberrations |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| KR880001707B1 (en) | Opto-electronic focusing error detection device | |
| CA2004982A1 (en) | Optical scanning device, mirror objective suitable for use in said device and optical write and/or read apparatus provided with said device | |
| JPS58220248A (en) | Optical pickup | |
| KR100349271B1 (en) | Optical pickup | |
| US3956582A (en) | Apparatus for reading a record carrier on which information is recorded in at least one track | |
| US5883874A (en) | Optical pickup system for selectively reading a multiple number of optical disks | |
| JPS6093644A (en) | Detecting method of optical focus | |
| JPH07101517B2 (en) | Photo detector | |
| KR940012274A (en) | Optical pickup | |
| JPH07182666A (en) | Light pickup system | |
| JP3092317B2 (en) | Optical pickup | |
| KR960005480A (en) | Focus error detection device | |
| KR100394314B1 (en) | Optical adjustment method of optical pickup | |
| JPS58208945A (en) | Method and apparatus for detecting focus | |
| JPS6159631A (en) | Optical pickup device | |
| JPH05290404A (en) | Optical head | |
| JPS5984352A (en) | Device for detecting focal error | |
| JP2809217B2 (en) | Tracking error detection device | |
| KR100711345B1 (en) | Photo detector having a double layer structure and optical pick up using a them | |
| JPH02168439A (en) | Optical recording information reproducing device | |
| JPS5933642A (en) | Optical pickup | |
| JPH02187929A (en) | Optical head | |
| KR0186153B1 (en) | An optical pickup device | |
| JPH07192295A (en) | Optical pickup | |
| JPS60157738A (en) | Optical information detector |