JPS5977641A - Optical head - Google Patents
Optical headInfo
- Publication number
- JPS5977641A JPS5977641A JP18770482A JP18770482A JPS5977641A JP S5977641 A JPS5977641 A JP S5977641A JP 18770482 A JP18770482 A JP 18770482A JP 18770482 A JP18770482 A JP 18770482A JP S5977641 A JPS5977641 A JP S5977641A
- Authority
- JP
- Japan
- Prior art keywords
- optical
- focusing lens
- light
- recording medium
- optical head
- 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
- G11B7/0901—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 track following only
-
- 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
- G11B7/08505—Methods for track change, selection or preliminary positioning by moving the head
Landscapes
- Optical Recording Or Reproduction (AREA)
Abstract
Description
【発明の詳細な説明】
本発明は回転する円板状の情報記録媒体ζこ対して光学
的に情報を記録し、あるいは記録された情報を読み取る
光デイスク装置における光学ヘッドｌこ関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical head in an optical disk device that optically records information on a rotating disc-shaped information recording medium or reads recorded information.
レーザ光を光源とし、このレーザ光を外部の情報源より
の信号で変調し、円板状の記録媒体に集束して照射する
こと（こより情報を記録し、あるいは一定強度の集束さ
ｎたレーザ光を記録媒体に照射して既に媒体−ヒに記録
さイ１、た情報を読み取る光デイスク装置の光学ヘッド
では集束された光ビームスポットが正確ｌこ媒体表面ｔ
こ当るようｉこ焦点位置の制御を行なうとともに、媒体
表面上の所定の位置に光ヒームスボッＩ−を位置させる
ためのトラッキング位置制御を行なう機能が安水される
。Ｉ・ラッキンク位置制御（仁おいては光ビームスポッ
トをトラックと直交方向（ディスクの半径方向）に動か
すことが必要である。光ビームスポットの移動は光学系
全部が搭載された光学ヘッド全体を動かすこ吉によって
行なうことができるが光学ヘッド全体は質量も大きく高
速な応答をさせるのが困難であるので、短い距離の光ビ
ームスポットの移動は一般に集束レンズのみを動かすこ
とによって行なわれている。但し集束レンズを動かせる
範θ（（は比較的小さいため長い距離の元ビームスポッ
トの移動は光学ヘッド全体を動がさねばならない。Using a laser beam as a light source, modulating this laser beam with a signal from an external information source, and focusing it on a disc-shaped recording medium (this is how information is recorded, or a laser beam that is focused at a certain intensity) is used as a light source. In the optical head of an optical disk device, which irradiates light onto a recording medium and reads information that has already been recorded on the medium, a focused light beam spot is accurately positioned on the medium surface.
In addition to controlling the focal point position to ensure that it hits the target, it also has a function of controlling the tracking position to position the optical beam spot at a predetermined position on the surface of the medium. I.Rack position control (In the case of Rack position control, it is necessary to move the light beam spot in the direction perpendicular to the track (radial direction of the disk).The movement of the light beam spot moves the entire optical head on which the entire optical system is mounted. This can be done by using a Kokichi, but since the entire optical head has a large mass and it is difficult to achieve a high-speed response, moving the light beam spot over a short distance is generally done by moving only the focusing lens. Since the range θ (() in which the focusing lens can be moved is relatively small, the entire optical head must be moved to move the original beam spot over a long distance.
長距離あるいは短距離いずれの移動時においても光学系
の特性を良い状態に保つためには集束レンズの位置が光
ヘッドに対してずれないことが望ましく、集束レンズが
動くときには九ヘッド筐体がそれに追従して動き、逆に
光ヘツドｍ体が動くときは集束レンズがそれに追従して
（あるいは筐体と一体で）動くように集束レンズ、光ヘ
ッド如体それぞれの動きを制御することが望まれる。こ
のような追従制御を実現するためｌこは光学ヘット筐体
に対する集束レンズの位置を正確に検出することが必要
であるが、従来の光学ヘッドにおいてはこのような位置
を直接検出する手段を有していなかったため、集束レン
ズを動かすアクチーエータの電流を検出する等の間接的
な手段（こよるしかなく、高速な光ビームスポットの移
動に対して光学ヘッド筐体と集束レンズとの位置ずれを
高速かつ高精度で検出するこきができず、従って光学・
＼ラド筐体と集束レンズとの位置ずれを小さく抑えるよ
うにそれぞれの動きを制御することが困難であった。In order to keep the characteristics of the optical system in good condition during either long-distance or short-distance movement, it is desirable that the position of the focusing lens does not shift relative to the optical head, and when the focusing lens moves, the nine head housing It is desirable to control the respective movements of the focusing lens and the optical head so that when the optical head moves, the focusing lens follows it (or moves integrally with the housing). . In order to realize such tracking control, it is necessary to accurately detect the position of the focusing lens relative to the optical head housing, but conventional optical heads do not have a means to directly detect such a position. Therefore, indirect means such as detecting the current of the actuator that moves the focusing lens are the only way to detect the positional deviation between the optical head housing and the focusing lens due to the rapid movement of the light beam spot. However, it is not possible to detect with high precision, so optical
It was difficult to control the movements of the RAD housing and the focusing lens so as to keep the positional deviation between them small.
本発明の目的は、以上の欠点を取り除くため光学ヘッド
筐体に対する集束レンズの正確な位置関係を示す信号を
発生することができる光学ヘッドを提供することｌこあ
る。SUMMARY OF THE INVENTION It is an object of the present invention to provide an optical head capable of generating a signal indicating the accurate positional relationship of a focusing lens with respect to an optical head housing in order to eliminate the above-mentioned drawbacks.
本発明の光ヘッドにょイｔは、集束レンズと元ヘッド筐
体との位置関係が正確に検出でき、高速かつ広範囲の光
ビームスポットの移動に対しても集束レンズの光ヘツド
筐体に対する位置ずイ″′Ｌを小さく抑える制御が可能
となり元ディスク装置こお（プる高精度のトラッキング
と高速トラックアクセスが実現できる。The optical head of the present invention can accurately detect the positional relationship between the focusing lens and the original head housing, and can accurately detect the positional relationship of the focusing lens with respect to the optical head housing even when the optical beam spot moves at high speed and over a wide range. It is possible to perform control to keep the value small, and it is possible to realize highly accurate tracking and high-speed track access from the source disk device.
以下に図面を参照して本発明の詳細な説明する。The present invention will be described in detail below with reference to the drawings.
第１図は本発明による光学ヘッドの一実施例を示すブロ
ック図である。半導体レーザ２がら出射されたレーザ光
はコリメートレンズ３偏光ビームスプリツタ４、％波長
板５を通過してプリズム２０に入射する。レーザ光の一
部はプリズム２０の入射面２１で反射され、２分割光セ
ンサ２２に入射する。プリズム２０を通過するレーザ光
はプリズム２０によって光路をほぼ直角に曲げられ、集
束レンズ２３により集束され記録媒体６の表面に微小光
スポット２４を形成する。一方、記録媒体６からの反射
光は集束レンズ％、プリズム２０．％波長板５を通過し
て偏光ビームスプリッタ４に戻り、％波長板５の働きに
よる偏光角の回転のために偏光ビームスプリッタ４によ
って半導体レーザ２の方向とは直角の方向に反射され、
ハーフミラ−７に入射する。ハーフミラ−７によって２
つに分割された反射光光束の一方はレンズ８によって絞
られ、ナイフェツジ９を経て焦点誤差検出のための光セ
ンサ１０に入射する。光センサ１０により検出された焦
点誤差信号は微小光スポット２４が記録媒体６の表面に
正確に形成されるように集束レンズ２３の記録媒体６表
面に垂直方向（照射光軸方向）の動きを制御する焦点制
御用に使用されるが焦点制御は本発明とは直接関係がな
いので詳しい説明は省略する。ハーフミラ−７によって
分割された反射光光束の他の一方はトラック位置誤差検
出のための元センサ１１に入射Ｃる。記録媒体６表面上
の情報トラックの位置は例えば、記録媒体６表面に形成
さｆした微小な幅と深さの溝によって規定することがで
きる。FIG. 1 is a block diagram showing an embodiment of an optical head according to the present invention. The laser light emitted from the semiconductor laser 2 passes through a collimator lens 3, a polarizing beam splitter 4, and a % wavelength plate 5, and enters a prism 20. A portion of the laser light is reflected by the entrance surface 21 of the prism 20 and enters the two-split optical sensor 22 . The optical path of the laser beam passing through the prism 20 is bent at a substantially right angle by the prism 20, and is focused by the focusing lens 23 to form a minute optical spot 24 on the surface of the recording medium 6. On the other hand, the reflected light from the recording medium 6 is reflected by the focusing lens % and the prism 20%. It passes through the wavelength plate 5 and returns to the polarizing beam splitter 4, and is reflected by the polarizing beam splitter 4 in a direction perpendicular to the direction of the semiconductor laser 2 due to rotation of the polarization angle by the action of the wavelength plate 5.
The light enters the half mirror 7. 2 by half mirror 7
One of the divided reflected light beams is focused by a lens 8, passes through a knife lens 9, and enters an optical sensor 10 for detecting a focus error. The focus error signal detected by the optical sensor 10 controls the movement of the focusing lens 23 in the direction perpendicular to the surface of the recording medium 6 (direction of the irradiation optical axis) so that a minute optical spot 24 is accurately formed on the surface of the recording medium 6. However, since focus control is not directly related to the present invention, detailed explanation will be omitted. The other part of the reflected light beam divided by the half mirror 7 enters the original sensor 11 for detecting a track position error. The position of the information track on the surface of the recording medium 6 can be defined, for example, by a groove of minute width and depth formed on the surface of the recording medium 6.
光ヒームスポット２４はトラック案内溝に対する位置が
ず４すると記録媒体６表面により反射さｎた反射光束の
ファーフイールドパターンζこ明暗の変化を生じ、これ
を２分割された光センサ１１で受けること？こより、光
ビームスポット２４の情凍トラックに対する位置ずれを
検出することができる。この光センサ１１ｉこより検出
されたトラック位置也差俳号を図には示していないトラ
ッキング制ｉ１１回路を介してレンズアクチュエータ１
２に帰環するこ七により光ビームスポット２４を所望の
情報トラック位置に保持するトラッキング制御動作が行
なわイ１．る。When the optical beam spot 24 is misaligned with respect to the track guide groove, a far field pattern ζ of the reflected light beam reflected by the surface of the recording medium 6 causes a change in brightness, which is detected by the optical sensor 11 divided into two. ? This makes it possible to detect the positional deviation of the light beam spot 24 with respect to the frozen track. The track position difference detected by this optical sensor 11i is transmitted to the lens actuator 1 via a tracking control circuit (not shown).
By returning to step 2, a tracking control operation is performed to maintain the light beam spot 24 at a desired information track position. Ru.
才だトラック位置誤差イに号をモニターしながら集束レ
ンズ２３（即ち光ビームスポット２４）をルＤかすこと
ζこより光ビーノ・スポット２４を別のトラック位置に
動かすトラックアクセス動作が行なわれる。A track access operation is performed in which the optical beam spot 24 is moved to another track position by moving the focusing lens 23 (that is, the optical beam spot 24) while monitoring the actual track position error.
集束レンズ％とプリズム２０は共通のアーム２５に取り
つけられでおり、レンズアクチュエータ１２によって一
体で動かさイ１．る。従って元ビーノ、スポット２４の
記録媒体６表面−ヒの位置を動かすためにレンズアクチ
ー上−夕１２によりで集束Ｉ／ンズ２３を動かすきプリ
ズム２０の入射面２１の光ヘツド筺体１に対する位置が
麦化し、反射面２１によって反射さ３％。The focusing lens and prism 20 are mounted on a common arm 25 and are moved together by the lens actuator 12.1. Ru. Therefore, in order to move the position of the spot 24 on the recording medium 6 surface, the focusing lens 23 is moved by the lens actuator 12, and the position of the entrance surface 21 of the prism 20 relative to the optical head housing 1 is changed. , 3% reflected by the reflective surface 21.
２分割光センサ２２に入射する光束の中心軸Ｑ）位置が
変化する。２分割光センサ２２ ｉｃ入射する光軸の位
置が変化するこ七により、２分割光セン」ｊ−２２０）
分割さイまた２つの光センサそイｔぞイＬｉこ入射する
光量が変化し、２つの元センサの出力の差をとることに
より集束し・ンズ２３の光ヘツド筐体１に対する位置ず
れを検出することができる。The central axis Q) position of the light beam incident on the two-split optical sensor 22 changes. 2-split optical sensor 22 IC By changing the position of the incident optical axis, the 2-split optical sensor 22
The amount of light incident on each of the two optical sensors changes, and by taking the difference between the outputs of the two original sensors, it is focused and detects the positional deviation of the lens 23 relative to the optical head housing 1. can do.
第２図は第１図に示す光ヘッドにおけるレンズ位置ずｔ
Ｌ検出手法をより詳しく説明するための図である。第２
図（ａ）は集束レンズ２３が光学ヘッド筺体１に対して
規定の位置をこ存在している、即ち位置ずれかない状態
を示している。（−のとき入射光３０はプリズム２０の
入射面２１（仁よってその−・部が反射さ１１．る。こ
の反射さイ１．た光束３１の中心６１１は２分割センサ
２２のセン寸分割線上に当るため２分割光センサ２２の
２つの光センサそｔｌ、ぞＩＬの受光敏は等しくなり２
つの光センサの出力の差は０と八る。Figure 2 shows the lens position t in the optical head shown in Figure 1.
FIG. 3 is a diagram for explaining the L detection method in more detail. Second
Figure (a) shows a state in which the focusing lens 23 is in a prescribed position with respect to the optical head housing 1, that is, there is no displacement. (When it is -, the incident light 30 is reflected by the - part of the incident surface 21 of the prism 20 (11. Therefore, the light receiving sensitivities of the two optical sensors Tl and IL of the two-split optical sensor 22 are equal, and 2
The difference between the outputs of the two optical sensors is 0.
一方、第２図（１））に示す如く集束レンズ２．３が）
ｔ′オーヘッド筐体１に対する規定位置からずイ１．こ
いろ局舎は入射面２Ｈこよって反射さ、ｌ’−また光束
３１の中ノｌｙ ’ｐＨが２分割光センサ２２の２一つ
の光セ〉′すの１つに当り（図では右側）該当オるセン
サの出力ツハ大きくなるため２つの光センサの出力の差
が０でに ／、ｆ （なり、集束レンズ２３の規定位１
梶からのｉ”ａｚ仮小すことになる。図から容易に分る
ようζこ入射面２１によっＣ反射さｎた光束３１の方向
は入射光３（１０力回と直父しておらず促って、２分ｉ
ｌｌ ｙＹ−セン＋−３２７表面の反射光束３１の光軸
位置は集束「・ンズ２３の（ｉ７置変化と同じ楡の変化
はしない。しかし、このことは位置Ａれ検出特性の低下
を招くものではなく、２分割光センサ２２の面積が県東
レンズ２３の移動晴に比して小さくて賢いというむしろ
好まし、い効果をもたらす。On the other hand, as shown in Fig. 2 (1)), the focusing lens 2.3)
t' Not in the specified position relative to the overhead housing 1.1. The color beam is reflected by the incident surface 2H, and the pH in the middle of the light beam 31 corresponds to one of the 21 light sections of the 2-split optical sensor 22 (on the right side in the figure). Since the output power of the corresponding sensor increases, the difference between the outputs of the two optical sensors becomes 0, /, f (and the specified position of the focusing lens 23 is 1
As can be easily seen from the figure, the direction of the light beam 31 reflected by the incident surface 21 is directly related to the incident light 3 (10 times). Please ask me for 2 minutes.
The optical axis position of the reflected light beam 31 on the 327 surface does not change in the same way as the (i7) position change of the focusing lens 23.However, this causes a deterioration of the position A deviation detection characteristics. Rather, the area of the two-split optical sensor 22 is smaller and smarter than the moving lens of the Kento lens 23, which is a rather desirable effect.
以上の如く本発明の光学ヘッドによイー１．ば、光へ？
ヘッド筐体ｌこ対する集束レンズのＩＪ＋き即し光ビー
ムスポットの動きを検出することかできろ。このように
千棹出ざイ′１．た光学ヘッド筐体と集束［２・ンズの
位置ずれを示す信号を使って光・＼ラド筐体を動ん・）
すことにより光学ヘッドＶ体と集ヰ・”レンズの間の位
置ずれを小さく抑えろことが０丁能と１．ｙ ４ｗ。ま
ｆこ逆に光学・＼ラド筐体を動かす際に位置ずに’Ｌ
イ’ｆｌｊ ′＋３’をレンズアクチー上−り１２に帰
項すく）ことにより集束レンズを光学ヘッド筐体の動き
に追従す７）ように動力）ずことができ場・節約に集束
レンズを筐体に固定することがＥ’ＪＩ′１ｆｆｌとな
る。As described above, the optical head of the present invention enables E1. B-to the light?
Is it possible to detect the movement of the IJ + focused light beam spot of the focusing lens that faces the head housing? In this way, Chisawa will come out'1. optical head housing and focusing [2.Moves the optical head housing using a signal indicating the positional deviation of the lens]
By doing so, it is possible to keep the positional deviation between the optical head V body and the focusing lens to a minimum. 'L
The focusing lens follows the movement of the optical head casing by returning 2'flj'+3' to the lens actuator 7). Fixing it to E'JI'1ffl.
ドζこおけるレンズ位置ずれ検出方法をよりＣ）−シく
説明するための図である。
−において、■・・・う”１．学−・クドシ体、２・・
半導体レー→Ｊ−１３・・コリノー１−１／ンズ、・１
・・・１齢ブ４−、シ −ムスブリ：）り、５・・）
４波長板、０・・・配録砂体、７・・ハーノミラー、８
・・・レンズ、９・・ｆイフエッジ、］（１、１１・・
・光センサ、１２・・・レンスアクナ、コー−−り、２
０・・・ブリズノ・、２（・・・入射面、２゛：訃・・
２分割几１うン′＋、＋１２３・・・集束１／ンズ、２
Ｆ・・光ヒームスホ、、 １．．２５・・ア−１Ｘをぞ
れぞ不、）７小寸。FIG. 6 is a diagram for explaining in more detail the method for detecting lens positional deviation in step C). In -, ■...u" 1. Academic - Kudoshi typeface, 2...
Semiconductor Ray → J-13... Collineau 1-1/ns, 1
...1st instar 4-, sea musburi:)ri, 5...)
4 wavelength plate, 0... Recorded sand body, 7... Herno mirror, 8
...lens, 9... f if edge, ](1, 11...
・Light sensor, 12... Lens Acuna, Corey, 2
0...Brizno..., 2(...Incidence plane, 2゛: Death...
2 division 几1un'+, +123...Focusing 1/ns, 2
F. Hikari Himsho,, 1. ．． 25...A-1X each, )7 small size.
Claims (1)
、情報記録媒体上に照射して該情報記録媒体への情報の
記録および記録された情報の読み出しを行なう光学ヘッ
ドにおいて、前記レーザ光源よりのレーザ光束の光軸を
直角に曲げて前記光集束レンズに入射させるとともに、
それ自身の入射面によって入射するレーザ光束の１部を
入射する光軸とは異なる方向に反射するように形成され
たプリズムと、前記プリズムの入射面によって反射され
た光を受ける２分割光センサと、前記光集束レンズと前
記プリズムを一体に結合して前記情報記録媒体の表面と
平行に動かす機構とを有し、前記２分割光センサの出力
によって前記光集束レンズの前記情報記録媒体の表面と
平行な方向の動きを検出することを特徴とする光学ヘッ
ド。In an optical head that records information on the information recording medium and reads out the recorded information by irradiating the laser beam from the laser light source onto the information recording medium through a focused 1/lens, the laser beam from the laser light source Bending the optical axis of the light beam at right angles and making it enter the light focusing lens,
a prism formed to reflect a part of the incident laser beam in a direction different from the incident optical axis by its own incident surface; and a two-split optical sensor that receives the light reflected by the incident surface of the prism. , a mechanism that combines the light focusing lens and the prism together and moves them parallel to the surface of the information recording medium, and the light focusing lens is moved between the surface of the information recording medium and the surface of the information recording medium by the output of the two-split optical sensor. An optical head characterized by detecting movement in parallel directions.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18770482A JPS5977641A (en) | 1982-10-26 | 1982-10-26 | Optical head |
| EP83303435A EP0098076A1 (en) | 1982-06-14 | 1983-06-14 | Beam access apparatus for optical disc system |
| US06/765,172 US4615023A (en) | 1982-06-14 | 1985-08-12 | Beam access apparatus for optical disc system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18770482A JPS5977641A (en) | 1982-10-26 | 1982-10-26 | Optical head |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS5977641A true JPS5977641A (en) | 1984-05-04 |
Family
ID=16210697
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP18770482A Pending JPS5977641A (en) | 1982-06-14 | 1982-10-26 | Optical head |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5977641A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4955010A (en) * | 1985-07-18 | 1990-09-04 | Kabushiki Kaisha Toshiba | Constant velocity track jump servo system for disc players |
| US7304407B2 (en) | 2003-12-26 | 2007-12-04 | Matsushita Electric Works, Ltd. | Linear oscillating actuator |
-
1982
- 1982-10-26 JP JP18770482A patent/JPS5977641A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4955010A (en) * | 1985-07-18 | 1990-09-04 | Kabushiki Kaisha Toshiba | Constant velocity track jump servo system for disc players |
| US7304407B2 (en) | 2003-12-26 | 2007-12-04 | Matsushita Electric Works, Ltd. | Linear oscillating actuator |
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