JPH07110962A - Recording and reproducing apparatus of optical recording medium - Google Patents
Recording and reproducing apparatus of optical recording mediumInfo
- Publication number
- JPH07110962A JPH07110962A JP5258437A JP25843793A JPH07110962A JP H07110962 A JPH07110962 A JP H07110962A JP 5258437 A JP5258437 A JP 5258437A JP 25843793 A JP25843793 A JP 25843793A JP H07110962 A JPH07110962 A JP H07110962A
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- JP
- Japan
- Prior art keywords
- recording
- light
- optical
- mode
- reproducing
- 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.)
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Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は情報の高密度記録が可能
なフォトンモード光記録媒体の記録再生装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording / reproducing apparatus for a photon mode optical recording medium which enables high density recording of information.
【０００２】[0002]
【従来の技術】近年書き換え可能な光記録媒体として、
フォトンモード反応を利用したフォトクロミック光記録
の研究が活発に行われている。このフォトクロミック材
料は所定波長の光を照射するとその光化学反応により分
子の構造が変化し、この構造変化に伴って特定波長の光
に対する吸光度や屈折率等の光学的特性変化が生じると
ともに、他の波長の光や熱を加えることで変化した分子
構造が元に戻るといった性質を有している。2. Description of the Related Art Recently, as a rewritable optical recording medium,
Researches on photochromic optical recording using photon mode reaction are being actively conducted. When this photochromic material is irradiated with light of a predetermined wavelength, the structure of the molecule changes due to its photochemical reaction, and this structural change causes changes in optical characteristics such as absorbance and refractive index for light of a specific wavelength, as well as other wavelengths. It has the property that the molecular structure changed by the application of light or heat returns to its original state.
【０００３】従ってフォトクロミック光記録媒体の記録
は、特定波長の光照射による分子構造変化によって行わ
れ、再生はこれに伴う光学的特性変化、特に吸光度の変
化を検出することによって実行される。Therefore, recording on the photochromic optical recording medium is carried out by a change in molecular structure caused by irradiation with light of a specific wavelength, and reproduction is carried out by detecting a change in optical characteristics associated therewith, particularly a change in absorbance.
【０００４】フォトクロミック光記録媒体では、異なる
吸収スペクトルを有する複数の材料を対応する複数の波
長のレーザ光で反応させて記録を行う波長多重記録や、
記録用レーザ光の偏光面に一致する配向を有する分子を
選択的に反応させる偏光多重記録等の方法によって、従
来の光磁気記録や相変化光記録等のヒートモード記録よ
りも高密度の記録が達成できる。In the photochromic optical recording medium, wavelength multiplex recording in which a plurality of materials having different absorption spectra are reacted with laser light of a plurality of corresponding wavelengths to perform recording, and
Higher density recording than conventional heat mode recording such as magneto-optical recording and phase change optical recording can be achieved by a method such as polarization multiplex recording in which molecules having an orientation that matches the polarization plane of the recording laser beam are selectively reacted. Can be achieved.
【０００５】ところでこのようなフォトンモード光記録
では光化学反応に閾値が存在しないため、再生を繰り返
すことによって徐々に反応が進行し、ついには記録され
た情報が破壊されてしまうという問題点があった。この
問題点に対し本発明者は先の特願平４−１９９９９０号
の明細書及び図面にて超低パワー再生方式の提案を行っ
た。By the way, in such a photon mode optical recording, since there is no threshold in the photochemical reaction, there is a problem that the reaction gradually progresses by repeating the reproduction and finally the recorded information is destroyed. . To solve this problem, the present inventor has proposed an ultra-low power reproducing system in the specification and drawings of Japanese Patent Application No. 4-199990.
【０００６】この超低パワー再生方式ではフォトンモー
ド記録媒体に記録された情報を再生するために数ｎＷ〜
数μＷの非常に低いレーザパワーを使用する。そして通
常このような媒体を利用する光ディスク装置において、
使用される半導体レーザをこのような低いパワーで安定
に制御することは困難である。In this ultra-low power reproducing system, several nW to reproduce the information recorded on the photon mode recording medium.
A very low laser power of a few μW is used. And in an optical disc device that normally uses such a medium,
It is difficult to stably control the semiconductor laser used with such low power.
【０００７】しかしながらこの種超低パワー再生用の装
置を情報記録時にも使用する場合には、再生モードと記
録モードとの間で数ｎＷの光強度（パワー）と数ｍＷ以
上の光強度（パワー）を切り換える必要があり、このた
めの光強度（パワー）の制御が難しいという問題点があ
った。However, when such a device for ultra-low power reproduction is used also during information recording, a light intensity (power) of several nW and a light intensity (power) of several mW or more between the reproduction mode and the recording mode. ) Has to be switched, which makes it difficult to control the light intensity (power) for this purpose.
【０００８】[0008]
【発明が解決しようとする課題】本発明は上記従来技術
の問題点に鑑みてなされたものであり、小型で且つ容易
に記録モードのパワーレベルと超低パワー再生モードと
のレベルの切り換えが容易に行えると共に、高周波での
出力が優れたフォトンモード光記録媒体の記録再生装置
を提供することを目的とするものである。SUMMARY OF THE INVENTION The present invention has been made in view of the above problems of the prior art, and is easy to switch between the power level of the recording mode and the level of the ultra-low power reproducing mode in a small size. It is an object of the present invention to provide a recording / reproducing apparatus for a photon-mode optical recording medium, which is capable of achieving high output at high frequencies.
【０００９】[0009]
【課題を解決するための手段】本発明は、フォトンモー
ドで情報の記録再生が可能な光記録媒体、情報を前記媒
体に記録しあるいは該媒体に記録された情報を読み出す
ための光を発する光源、前記光源からの光を前記媒体に
集光させるレンズ系、情報の再生時に前記媒体の反射光
を検出する光検出器、前記媒体からの反射光を前記光検
出器へ導くための光路分離手段、情報の記録時に前記光
源からの光の強度を記録すべき情報に応じて変調すると
共に情報の再生時に前記光源からの光の強度を一定にす
る光源駆動手段、前記光源と前記光路分離手段との間に
設けられ情報の記録時には光源からの光の中心部を減衰
又は遮蔽し周辺部をそのまま通過させるとともに情報の
再生時に前記光源からの光の強度を数ｎＷ〜数μＷの一
定の低い値に減衰させる光強度減衰素子とよりなる。SUMMARY OF THE INVENTION The present invention is an optical recording medium capable of recording and reproducing information in a photon mode, and a light source which emits light for recording information on the medium or reading information recorded on the medium. A lens system for collecting the light from the light source on the medium, a photodetector for detecting the reflected light of the medium at the time of reproducing information, and an optical path separating means for guiding the reflected light from the medium to the photodetector. A light source driving unit that modulates the intensity of light from the light source during recording of information according to the information to be recorded and keeps the intensity of light from the light source constant at the time of reproducing information, the light source and the optical path separating unit, Between the light source and the center portion of the light from the light source when the information is recorded and the peripheral portion is passed as it is, and the intensity of the light from the light source when reproducing the information is a constant low value of several nW to several μW. Decay to More becomes the light intensity attenuation element which.
【００１０】[0010]
【作用】図２（Ａ）（Ｂ）の原理図を用いて本発明の作
用を説明する。同図において３０１は記録モード時の図
示しない光源からの強い放射光、１００は光記録媒体、
２は対物レンズ系、４０１は記録モード時に前記光源か
らの放射光の周辺部３０２をその強度を変化させずにそ
のまま通過させ、中心部分の強度を減衰又は中心部分の
光を遮蔽させるための光強度減衰素子、３０３は再生モ
ード時の図示しない光源からの放射光である。The operation of the present invention will be described with reference to the principle diagrams of FIGS. In the figure, 301 is a strong radiation light from a light source (not shown) in the recording mode, 100 is an optical recording medium,
Reference numeral 2 denotes an objective lens system, and 401 denotes light for passing the peripheral portion 302 of the emitted light from the light source as it is without changing its intensity in the recording mode and for attenuating the intensity of the central portion or shielding the light of the central portion. An intensity attenuator element 303 is a light emitted from a light source (not shown) in the reproduction mode.
【００１１】前記光強度減衰素子４０１は回転制御手段
によってその中心の回転軸４００の回りに自由に回転す
るができ、図２（Ａ）では水平位置にあって前述の如く
光３０１の周辺部３０２をそのまま通過させ、図２
（Ｂ）では垂直位置にあって放射光３０３を全部減衰さ
せて超低パワー光３０４を作る。The light intensity attenuating element 401 can be freely rotated around a rotation axis 400 at its center by a rotation control means, and is in a horizontal position in FIG. 2 through the
In (B), the radiated light 303 is at a vertical position and all the radiated light 303 is attenuated to produce an ultra-low power light 304.
【００１２】なお、前記光源からの放射光３０１、３０
３は同じ強度で当ても良いし、放射光３０３が３０１に
比較してかなり強度の低下したものであっても良い。こ
のような構成において、記録モード図２（Ａ）では、光
強度減衰素子４０１は前記の回転機構によってビームの
軸に直交した回転軸４００の回りに回転し、光源からの
比較的強い放射光３０１の中心部を遮り、周辺部３０２
だけが減衰されることなく通過して対物レンズ２によっ
てフォトンモード媒体１００に集光される。Radiation light 301, 30 from the light source
3 may be applied with the same intensity, or the intensity of the emitted light 303 may be considerably lower than that of 301. In such a configuration, in the recording mode of FIG. 2A, the light intensity attenuating element 401 is rotated around the rotation axis 400 orthogonal to the axis of the beam by the above rotation mechanism, and the comparatively strong radiation light 301 from the light source is emitted. Around the central part of the
Only passes through without being attenuated and is focused on the photon mode medium 100 by the objective lens 2.
【００１３】このときビームの強度分布は周辺部の方が
強いので超解像効果によって通常より半値幅の狭い記録
レーザスポットが形成され、より小さい記録マークが形
成される。このようなビーム強度分布による超解像効果
については例えば光学第２１巻第７号４４２頁〜の「光
ピックアップヘッドにおける超分解能の可能性」にて良
く知られている。At this time, since the intensity distribution of the beam is stronger in the peripheral portion, a recording laser spot having a half-value width narrower than usual is formed by the super-resolution effect, and a smaller recording mark is formed. The super-resolution effect due to such a beam intensity distribution is well known, for example, in "Possibility of super-resolution in an optical pickup head" of Optics, Vol. 21, No. 7, p.
【００１４】ここで図２（Ａ）の上下方向を記録トラッ
ク長さ方向に取っておけば通常より短い記録マークが形
成可能であるので、高周波領域における再生出力が改善
されることになる。そしてフォトンモード光記録におけ
る高い周波数（特にスポット径と同程度以下の記録マー
クに相当する周波数）での出力低下という問題点がこの
記録装置では解決される。If the vertical direction of FIG. 2A is set to the recording track length direction, a recording mark shorter than usual can be formed, so that the reproduction output in the high frequency region is improved. This recording apparatus solves the problem of output reduction at high frequencies in photon mode optical recording (especially at frequencies corresponding to recording marks that are approximately equal to or smaller than the spot diameter).
【００１５】一方再生モード図２（Ｂ）では回転制御手
段により光強度減衰素子４０１は９０°回転した位置に
固定され、記録再生用光源からの放射光３０３を全て減
衰させることになる。これによって超低パワーレベルに
まで低下したレーザ光３０４がレンズ系２によって媒体
１００へと集光される。On the other hand, in the reproduction mode of FIG. 2B, the light intensity attenuating element 401 is fixed at a position rotated by 90 ° by the rotation control means, and all the radiation light 303 from the recording / reproducing light source is attenuated. As a result, the laser beam 304 lowered to the ultra-low power level is focused on the medium 100 by the lens system 2.
【００１６】なお、前記放射光３０３は記録モードにお
ける光３０１の強度と同じでも構わないが、半導体レー
ザを光源に用いた場合は安定に制御できる範囲で注入電
流を調整して超低パワーレベルのレーザ光３０４の微調
整を行っても良い。The emitted light 303 may have the same intensity as that of the light 301 in the recording mode, but when a semiconductor laser is used as a light source, the injection current is adjusted within a range that can be stably controlled to obtain an ultra-low power level. Fine adjustment of the laser beam 304 may be performed.
【００１７】このような構成の光記録・超低パワー再生
装置では、光強度減衰素子４０１がビームの光路内だけ
で変化して光路の外部への出し入れがないのでそれだけ
ピックアップ光学系を小型簡略化することができるだけ
でなく。前述したように記録モード時には超解像効果に
より高周波数特性が改善される。In the optical recording / ultra-low power reproducing apparatus having such a configuration, the light intensity attenuating element 401 changes only within the optical path of the beam and does not enter or leave the optical path. Not only can you do that. As described above, the high frequency characteristic is improved by the super-resolution effect in the recording mode.
【００１８】[0018]
【実施例】以下作用の項で述べた原理を応用した光記録
媒体の記録再生装置の一実施例について図面に基づいて
詳細に説明する。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a recording / reproducing apparatus for an optical recording medium to which the principle described in the section of operation is applied will be described in detail with reference to the drawings.
【００１９】図１は記録再生装置の全体構成を示すブロ
ック図であり、前記図２と同じ構成要素については同じ
符号をつけて示す。フォトンモードで反応するフォトク
ロミック材料は例えば６３０ｎｍ付近で吸収を有するも
のが多いので、記録再生用光源５１としては６３０ｎｍ
付近のレーザを放射する半導体レーザが使用できる。こ
の半導体レーザ５１は、半導体レーザ駆動回路５１１及
び記録再生モード切り換え回路５１２の作用により、記
録モード時には記録信号に対応した変調されたレーザパ
ルスが放射され、再生モード時には一定レベルのレーザ
光が放射されるようになっている。FIG. 1 is a block diagram showing the overall structure of the recording / reproducing apparatus, and the same components as those in FIG. 2 are designated by the same reference numerals. Since many photochromic materials that react in the photon mode have absorption in the vicinity of 630 nm, for example, 630 nm is used as the recording / reproducing light source 51.
A semiconductor laser that emits a laser in the vicinity can be used. The semiconductor laser 51 emits a modulated laser pulse corresponding to a recording signal in the recording mode and a constant level of laser light in the reproducing mode by the operation of the semiconductor laser driving circuit 511 and the recording / reproducing mode switching circuit 512. It has become so.
【００２０】前記光源５１からの放射光はコリメートレ
ンズ５２により整形され、光強度減衰素子４０１によっ
て記録モード時にはビームの中心部が遮蔽され、周辺部
が減衰されることなく透過し、再生モード時にはビーム
全体が超低パワーレベル（数ｎＷ〜数μＷ）にまで減衰
される。The emitted light from the light source 51 is shaped by the collimator lens 52, the central portion of the beam is shielded by the light intensity attenuating element 401 in the recording mode, the peripheral portion is transmitted without being attenuated, and the beam is emitted in the reproducing mode. The whole is attenuated to a very low power level (several nW to several μW).
【００２１】前記光強度減衰素子４０１は図２において
説明したように光強度減衰素子制御系５１３及び記録再
生モード切り換え回路５１２によってビーム軸に直交し
た回転軸の回りでモードに応じて回転するように制御さ
れる。As described with reference to FIG. 2, the light intensity attenuating element 401 is rotated by the light intensity attenuating element control system 513 and the recording / reproducing mode switching circuit 512 around the rotation axis orthogonal to the beam axis according to the mode. Controlled.
【００２２】前記光減衰素子４０１を通過した部分ビー
ム３０４は偏光ビームスプリッタ５３、λ／４板５４を
通過し、ダイクロイックミラー７０で反射されて対物レ
ンズ系２によりフォトンモード光記録媒体１００に集光
される。The partial beam 304 that has passed through the optical attenuator 401 passes through the polarization beam splitter 53 and the λ / 4 plate 54, is reflected by the dichroic mirror 70, and is focused on the photon mode optical recording medium 100 by the objective lens system 2. To be done.
【００２３】再生モードでは媒体からの反射光が再び対
物レンズ２を透過し、ダイクロイックミラー７０で反射
され、光路分離手段であるλ／４板５４、偏光ビームス
プリッタ５３の作用で光検出器５６側に光路が変換さ
れ、レンズ５５によって検出器５６へと入射し、再生出
力が得られる。In the reproducing mode, the reflected light from the medium is transmitted through the objective lens 2 again and is reflected by the dichroic mirror 70, and the λ / 4 plate 54 as the optical path separating means and the polarization beam splitter 53 act to the photodetector 56 side. The optical path is changed to, and the light is incident on the detector 56 by the lens 55, and a reproduction output is obtained.
【００２４】本実施例では超低パワー再生時にフォーカ
ス／トラッキングサーボが不安定にならないように、サ
ーボの光学系が別途設けられ、サーボ用光源６１、コリ
メートレンズ６２、偏光ビームスプリッタ６３、λ／４
板６４、半導体レーザ駆動回路６１１、フォーカス／ト
ラッキングエラー検出用光学系６７、フォーカス／トラ
ッキング回路６７１で構成されている。In the present embodiment, a servo optical system is separately provided so that the focus / tracking servo does not become unstable during reproduction of ultra-low power, and the servo light source 61, the collimator lens 62, the polarization beam splitter 63, and λ / 4 are provided.
It is composed of a plate 64, a semiconductor laser drive circuit 611, a focus / tracking error detection optical system 67, and a focus / tracking circuit 671.
【００２５】前記光源６１としては例えば波長８３０ｎ
ｍの半導体レーザを用いることができる。このレーザ６
１の放射光はコリメートレンズ６２により整形され、ダ
イクロイックミラー７０を透過して対物レンズ２により
媒体１００へと集光される。The light source 61 has, for example, a wavelength of 830n.
m semiconductor laser can be used. This laser 6
The radiated light 1 is shaped by the collimator lens 62, passes through the dichroic mirror 70, and is focused on the medium 100 by the objective lens 2.
【００２６】そして媒体１００からの反射光はλ／４板
６４及び偏光ビームスプリッタ６３の作用により光路が
変換されて公知のフォーカス／トラッキングエラー検出
用光学系６７へと入射する。これによって得られたフォ
ーカス／トラッキングエラー信号に基づいてフォーカス
／トラッキング用回路６７１により対物レンズ系２が駆
動され、これらのサーボが実行される。なお、サーボ用
光源６１の出力は記録再生のモードによらず一定で良
い。The reflected light from the medium 100 has its optical path changed by the action of the λ / 4 plate 64 and the polarization beam splitter 63, and enters the known focus / tracking error detecting optical system 67. The objective / lens system 2 is driven by the focus / tracking circuit 671 based on the focus / tracking error signal thus obtained, and these servos are executed. The output of the servo light source 61 may be constant regardless of the recording / reproducing mode.
【００２７】[0027]
【発明の効果】以上の説明のように本発明によればフォ
トンモード光記録媒体の繰り返し再生による低下を防
ぎ、小型簡略化されたピックアップ光学系を有し、且つ
高周波領域での出力が高くできる光記録媒体の記録再生
装置を提供できる効果が期待できる。As described above, according to the present invention, it is possible to prevent the deterioration due to the repeated reproduction of the photon mode optical recording medium, to have the pickup optical system which is small and simplified, and to increase the output in the high frequency region. An effect of providing a recording / reproducing device for an optical recording medium can be expected.
【図面の簡単な説明】[Brief description of drawings]
【図１】本発明の記録再生装置の一実施例を示すブロッ
ク図である。FIG. 1 is a block diagram showing an embodiment of a recording / reproducing apparatus of the present invention.
【図２】本発明の原理を示すブロック図である。FIG. 2 is a block diagram showing the principle of the present invention.
１００ 光記録媒体 ２ 対物レンズ系 ３０１、３０２ 記録用光 ４０１ 光強度減衰素子 ５１ 記録再生用光源 ５２、６２ コリメートレンズ ５３、６５ 偏光ビームスプリッタ ５４、６４ λ／４板 ５５ レンズ ５６ 光検出器 ６１ サーボ用光源 ６７ フォーカス／トラッキングエラー検出
用光学系 ７０ ダイクロイックミラー100 Optical recording medium 2 Objective lens system 301, 302 Recording light 401 Light intensity attenuation element 51 Recording / reproducing light source 52, 62 Collimating lens 53, 65 Polarizing beam splitter 54, 64 λ / 4 plate 55 Lens 56 Photodetector 61 Servo Light source 67 Focus / Tracking error detection optical system 70 Dichroic mirror
Claims (1)
な光記録媒体、情報を前記媒体に記録しあるいは該媒体
に記録された情報を読み出すための光を発する光源、前
記光源からの光を前記媒体に集光させるレンズ系、情報
の再生時に前記媒体の反射光を検出する光検出器、前記
媒体からの反射光を前記光検出器へ導くための光路分離
手段、情報の記録時に前記光源からの光の強度を記録す
べき情報に応じて変調すると共に情報の再生時に前記光
源からの光の強度を一定にする光源駆動手段、前記光源
と前記光路分離手段との間に設けられ情報の記録時には
光源からの光の中心部を減衰又は遮蔽し周辺部をそのま
ま通過させるとともに情報の再生時に前記光源からの光
の強度を数ｎＷ〜数μＷの一定の低い値に減衰させる光
強度減衰素子とよりなる光記録媒体の記録再生装置。1. An optical recording medium capable of recording and reproducing information in a photon mode, a light source for emitting light for recording information on the medium or reading information recorded on the medium, and light for emitting light from the light source. A lens system for condensing on a medium, a photodetector for detecting reflected light of the medium at the time of reproducing information, an optical path separating means for guiding the reflected light from the medium to the photodetector, from the light source for recording information The light intensity of the light source is modulated according to the information to be recorded, and the intensity of the light from the light source is kept constant at the time of reproducing the information, and the information recording is provided between the light source and the optical path separating means. Sometimes a light intensity attenuating element that attenuates or shields the central part of the light from the light source and allows the light to pass through the peripheral part as it is, and at the time of reproducing information, attenuates the intensity of the light from the light source to a constant low value of several nW to several μW. Than Recording and reproducing apparatus that the optical recording medium.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5258437A JPH07110962A (en) | 1993-10-15 | 1993-10-15 | Recording and reproducing apparatus of optical recording medium |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5258437A JPH07110962A (en) | 1993-10-15 | 1993-10-15 | Recording and reproducing apparatus of optical recording medium |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH07110962A true JPH07110962A (en) | 1995-04-25 |
Family
ID=17320196
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5258437A Pending JPH07110962A (en) | 1993-10-15 | 1993-10-15 | Recording and reproducing apparatus of optical recording medium |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH07110962A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0499202A (en) * | 1990-08-10 | 1992-03-31 | Nikko Kyodo Co Ltd | Manufacture of colored zinc powder |
| WO2007123065A1 (en) * | 2006-04-18 | 2007-11-01 | Panasonic Corporation | Optical information recording/reproducing device |
-
1993
- 1993-10-15 JP JP5258437A patent/JPH07110962A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0499202A (en) * | 1990-08-10 | 1992-03-31 | Nikko Kyodo Co Ltd | Manufacture of colored zinc powder |
| WO2007123065A1 (en) * | 2006-04-18 | 2007-11-01 | Panasonic Corporation | Optical information recording/reproducing device |
| US8031577B2 (en) | 2006-04-18 | 2011-10-04 | Panasonic Corporation | Optical information recording/reproducing device |
| JP4795429B2 (en) * | 2006-04-18 | 2011-10-19 | パナソニック株式会社 | Optical information recording / reproducing device |
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