JP2008097681A - Optical information recording and reproducing device - Google Patents

Optical information recording and reproducing device Download PDF

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JP2008097681A
JP2008097681A JP2006276215A JP2006276215A JP2008097681A JP 2008097681 A JP2008097681 A JP 2008097681A JP 2006276215 A JP2006276215 A JP 2006276215A JP 2006276215 A JP2006276215 A JP 2006276215A JP 2008097681 A JP2008097681 A JP 2008097681A
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information recording
reproducing apparatus
aberration
optical information
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JP4770685B2 (en
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Teruhiro Shiono
照弘 塩野
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Panasonic Holdings Corp
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Matsushita Electric Industrial Co Ltd
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Abstract

<P>PROBLEM TO BE SOLVED: To provide an information recording and reproducing device which can perform high-speed parallel recording or high-speed parallel reproduction satisfactorily by suppressing deterioration of convergence spot performance with independently controllable multi-beams in an optical information recording and reproducing device of an information recording medium on which information can be recorded three-dimensionally. <P>SOLUTION: The optical information recording and reproducing device is provided with: a light source 20 for recording or reproduction provided with oscillation parts 23a to 23c which can be driven independently; an objective lens 6 which condenses outgoing lights 22a to 22c from respective oscillation parts 23a to 23c on the information recording medium 21 having a recording part 3 in which the information can be recorded three-dimensionally; and photodetectors 19a to 19c and 19'a to 19'c for respectively detecting reflected lights 17a to 17c and 17'a to 17'c from the information recording medium 21. The optical information recording and reproducing device is equipped with an oblique incident aberration reduction optical element 24 which reduces aberration caused by oblique incidence corresponding to the outgoing lights 8b and 8c incident on the objective lens 6 obliquely in an optical path between the light source 20 and the objective lens 6. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

３次元的に記録可能な情報記録媒体の光学情報記録再生装置に関し、特に、独立制御可能なマルチビームにより、その集光スポット性能の劣化を抑えて良好に並列記録または並列再生ができる情報記録再生装置を提供する。   The present invention relates to an optical information recording / reproducing apparatus for a three-dimensionally recordable information recording medium, and in particular, information recording / reproducing that can be favorably performed in parallel recording or reproducing while suppressing deterioration of the condensed spot performance by using an independently controllable multi-beam. Providing equipment.

光学情報記録再生装置は、コンパクトディスク（ＣＤ）、ＤＶＤ等の光ディスクや光カードメモリ等の光学情報記録媒体に、情報を記録再生する装置である。近年、光学情報記録媒体のさらなる大容量化と、その大容量光学情報記録媒体に対して、高速記録または高速再生できる光学情報記録再生装置が求められている。   An optical information recording / reproducing apparatus is an apparatus for recording / reproducing information on / from an optical information recording medium such as an optical disk such as a compact disk (CD) or DVD or an optical card memory. In recent years, there has been a demand for an optical information recording / reproducing apparatus that can further increase the capacity of an optical information recording medium and perform high-speed recording or high-speed reproduction with respect to the large-capacity optical information recording medium.

従来の大容量情報記録媒体として、非特許文献１には、記録層を複数層構成した多層の情報記録媒体が記載されている。記録層を、中間層を挟んで複数層交互に形成することにより、記録容量をその層数の分だけ増加させることが可能である。上記多層の情報記録媒体の光学情報記録再生装置としては、Ｔｉサファイアレーザ等の大パワを発するフェムト秒レーザを記録用光源として具備し、非線形現象の１つである２光子吸収過程を用いて、上記多層の情報記録媒体に記録ピットを記録し、再生用光源としてはＨｅ−Ｎｅレーザ等を具備し、低パワでその記録ピットに集光して反射光を光検出器で検出することにより信号再生できる。   As a conventional large-capacity information recording medium, Non-Patent Document 1 describes a multilayer information recording medium having a plurality of recording layers. By forming a plurality of recording layers alternately with an intermediate layer in between, the recording capacity can be increased by the number of layers. As an optical information recording / reproducing apparatus for the multilayer information recording medium, a femtosecond laser emitting a large power such as a Ti sapphire laser is provided as a recording light source, and a two-photon absorption process which is one of nonlinear phenomena is used. Signals are recorded by recording pits on the multilayer information recording medium, having a He-Ne laser or the like as a light source for reproduction, condensing the recording pits with low power, and detecting reflected light with a photodetector. Can play.

また、従来の高速記録／再生可能な光学情報記録再生装置として、特許文献１には、独立に駆動できる３つの光源を用いた光学ヘッドが記載され、３つのトラック上に同時に記録または再生する例が示されている。   Further, as a conventional optical information recording / reproducing apparatus capable of high-speed recording / reproducing, Patent Document 1 describes an optical head using three light sources that can be driven independently, and an example of recording or reproducing simultaneously on three tracks. It is shown.

特許文献２には、記録してすぐに別のビームでモニターすることを目的として、記録用と再生／ベリファイ用の２光源を用いて、対物レンズに対する光の斜め入射によるスポット性能の劣化の防止が可能な光学ヘッドが記載されている。図６は、特許文献２に記載された光ピックアップの基本構成図である。光源２００は、再生／ベリファイ用の半導体レーザチップ２３０ａと記録用の半導体レーザチップ２３０ｂとを具備し、上記レーザチップ２３０ａに近接して１／２波長板３１０が設置されている。この１／２波長板３１０により、両光源２３０ａ、２３０ｂを出射したそれぞれのビーム２２０ａと２２０ｂの偏光方向は互いに直交し、その後、両ビームとも、コリメータレンズ１６０で略平行光になってウオラストンプリズム３００に入射する。出射ビーム２２０ｂのみが、偏光方向の違いによりウオラストンプリズム３００により光軸が曲げられ、その結果、２つの出射光２２０ａと２２０ｂはほぼ平行化される。その結果、両ビームとも、対物レンズ６０にほぼ垂直入射する（入射角は０に近い）ことにより、２つのビームの集光スポットの劣化はほぼ防止することができる。
河田善正他：”多層膜構造を有する有機記録媒体を用いた３次元光メモリ”、Ｏｐｔｉｃｓ Ｊａｐａｎ２０００講演予稿集ｐｐ．９５−９６（２０００年） 特許第３４７６８７９号公報（第４頁、図３） 特開２００３−６７９７０号公報（第４〜５頁、図１） In Patent Document 2, for the purpose of monitoring with a separate beam immediately after recording, two light sources for recording and reproduction / verification are used to prevent deterioration of spot performance due to oblique incidence of light on the objective lens. An optical head is described. FIG. 6 is a basic configuration diagram of the optical pickup described in Patent Document 2. In FIG. The light source 200 includes a semiconductor laser chip 230a for reproduction / verification and a semiconductor laser chip 230b for recording, and a half-wave plate 310 is installed in the vicinity of the laser chip 230a. The polarization directions of the beams 220a and 220b emitted from the light sources 230a and 230b are orthogonal to each other by the half-wave plate 310, and then both beams are substantially collimated by the collimator lens 160 and become Wollaston. The light enters the prism 300. Only the outgoing beam 220b has its optical axis bent by the Wollaston prism 300 due to the difference in polarization direction, and as a result, the two outgoing lights 220a and 220b are substantially parallelized. As a result, both beams are substantially perpendicularly incident on the objective lens 60 (incident angle is close to 0), so that the deterioration of the condensed spots of the two beams can be substantially prevented.
Yoshimasa Kawada et al .: “Three-dimensional optical memory using an organic recording medium having a multilayer structure”, Optics Japan 2000 Lecture Proceedings pp. 95-96 (2000) Japanese Patent No. 3476879 (page 4, FIG. 3) Japanese Unexamined Patent Publication No. 2003-67970 (pages 4-5, FIG. 1)

特許文献１に示した従来の光学情報記録再生装置は、複数の発光点（発振部）を有する光源を有し、その発光点は熱の影響も考慮することにより、ある程度の間隔で配置した構成であるが、中央の発光点からの出射ビームが対物レンズに垂直入射するように配置した場合、周辺の発光点からの出射ビームは、対物レンズへ斜め入射になってしまうため、それが原因で収差が発生して、その集光スポット性能が劣化する傾向があった。   The conventional optical information recording / reproducing apparatus shown in Patent Document 1 has a light source having a plurality of light emitting points (oscillators), and the light emitting points are arranged at a certain interval in consideration of the influence of heat. However, when the output beam from the central emission point is arranged so that it is perpendicularly incident on the objective lens, the output beam from the peripheral emission point is obliquely incident on the objective lens. There was a tendency for aberration to occur and the performance of the focused spot to deteriorate.

それを解決する目的で、特許文献１の構成に、特許文献２に記載されたウオラストンプリズムを組み合わせた場合は、その光学系が複雑かつ高価となり、しかも基本的にｘとｙの２方向しかない偏光を用いるため、光源の発光点の数は、たかだか２つまでである、つまり、同時に記録または再生するピットの数は最大で２つであり、それ以上の並列記録／再生はできないという課題があった。   In order to solve this problem, when the Wollaston prism described in Patent Document 2 is combined with the configuration of Patent Document 1, the optical system becomes complicated and expensive, and basically two directions of x and y Since only polarized light is used, the number of light emitting points of the light source is at most two, that is, the maximum number of pits to be recorded or reproduced at the same time is two, and further parallel recording / reproduction cannot be performed. There was a problem.

非特許文献１に示した３次元的に記録可能な情報記録媒体を、特許文献１に示したようなマルチビームで、高速記録または再生が可能な光学情報記録再生装置を構成することを目的とした場合、マルチビームの数が２つで良いなら、光学系が複雑になるものの、上記文献から、ウオラストンプリズムを用いるような偏光を利用した構成を導くことができる。   An object of the present invention is to constitute an optical information recording / reproducing apparatus capable of performing high-speed recording or reproduction with a multi-beam as shown in Patent Document 1, using an information recording medium capable of three-dimensional recording shown in Non-Patent Document 1. In this case, if the number of multi-beams is only two, the optical system becomes complicated, but a configuration using polarized light such as a Wollaston prism can be derived from the above document.

しかしながら、さらにマルチビームの数を増加（３つ以上）させて高速記録または高速再生を行いたい場合は、偏光が利用できないために特許文献２の光学系を用いることができず、マルチビームの数が増えるほど中央部からずれた発光点からのビームは対物レンズに一層斜入射するため、それが原因で収差が益々大きくなり集光特性が劣化する傾向にあった。   However, when it is desired to further increase the number of multi-beams (three or more) and perform high-speed recording or high-speed reproduction, the optical system of Patent Document 2 cannot be used because polarization cannot be used, and the number of multi-beams. As the beam increases, the beam from the light emitting point deviated from the central part is incident on the objective lens more obliquely, and as a result, the aberration becomes larger and the condensing characteristic tends to deteriorate.

従って、従来例を組み合わせても、３つ以上の発光点を有する光源に対して、対物レンズに斜め入射になるビームの集光スポット性能の劣化が避けられないという課題があった。また２つの発光点を有する光源に対しても、偏光光学系を使うために構成が複雑で高価になるという課題があった。また、何らかの方法で発光点の間隔をかなり小さくできても、情報記録媒体からの複数の反射光を検出する場合、発光点の間隔が小さすぎるとその分離検出が困難になるという課題もあった。   Therefore, even if the conventional examples are combined, there has been a problem that degradation of the condensing spot performance of the beam obliquely incident on the objective lens is unavoidable with respect to the light source having three or more light emitting points. In addition, the light source having two light emitting points has a problem that the configuration is complicated and expensive because the polarization optical system is used. In addition, even if the interval between the light emitting points can be considerably reduced by some method, when detecting a plurality of reflected lights from the information recording medium, there is a problem that separation and detection becomes difficult if the interval between the light emitting points is too small. .

本発明は、従来技術における前記課題を解決するためになされたものであり、独立制御可能な複数の出射光を発するマルチビーム光源を用いた３次元情報記録媒体の光学情報記録再生装置に関し、対物レンズに斜め入射になるビームの集光スポット性能の劣化が防止できる情報記録再生装置を提供することを目的とする。   The present invention has been made in order to solve the above-described problems in the prior art, and relates to an optical information recording / reproducing apparatus for a three-dimensional information recording medium using a multi-beam light source that emits a plurality of independently controlled emission lights. An object of the present invention is to provide an information recording / reproducing apparatus capable of preventing the deterioration of the focusing spot performance of a beam obliquely incident on a lens.

前記従来の課題を解決するために、本発明は、独立に駆動可能な複数の発振部を備えた記録用または再生用の光源と、３次元的に記録可能な記録部を有する情報記録媒体に上記発振部からの複数の出射光をそれぞれ集光する対物レンズと、上記情報記録媒体からの複数の反射光をそれぞれ検出する光検出器とを備え、上記光源と上記対物レンズの光路間に、上記対物レンズへ斜め入射する出射光に対応して、斜め入射により生じる収差を低減する斜入射収差低減光学素子を具備することを特徴とする光学情報記録再生装置である。   In order to solve the above-described conventional problems, the present invention provides an information recording medium having a recording or reproducing light source including a plurality of independently oscillating units and a recording unit capable of three-dimensional recording. An objective lens that condenses each of the plurality of outgoing lights from the oscillating unit, and a photodetector that detects a plurality of reflected lights from the information recording medium, respectively, between the light source and the optical path of the objective lens, An optical information recording / reproducing apparatus comprising an oblique incident aberration reducing optical element for reducing aberration caused by oblique incidence corresponding to outgoing light obliquely incident on the objective lens.

これにより、３次元的に記録可能な情報記録媒体に対して、高速に並列記録または並列再生可能な光学情報記録再生装置に関し、特に、対物レンズに斜め入射になるビームの集光スポット性能の劣化が低減できる情報記録再生装置を実現することができる。   Accordingly, the present invention relates to an optical information recording / reproducing apparatus capable of performing parallel recording or parallel reproduction at high speed on an information recording medium that can be recorded three-dimensionally. It is possible to realize an information recording / reproducing apparatus that can reduce the above.

以上説明したように、本発明によれば、３次元的に記録可能な大容量情報記録媒体の光学情報記録再生装置に関し、独立制御可能な複数の出射光を発するマルチビーム光源からの複数の出射光に対応して、対物レンズへ斜入射となる出射光の収差を低減する斜入射収差低減光学素子を具備したことにより、対物レンズに斜め入射になるビームの集光スポット性能の劣化が低減でき、これらのマルチビームにより高速並列記録または高速並列再生が可能な情報記録再生装置を実現することができる。また、ウオラストンプリズムのような高価な偏光部品を使用しないため、光学系が簡単で、安価になるという効果もある。   As described above, according to the present invention, an optical information recording / reproducing apparatus for a large-capacity information recording medium that can be recorded three-dimensionally has a plurality of light sources emitted from a multi-beam light source that emits a plurality of independently controllable light beams. Corresponding to the incident light, equipped with an oblique incidence aberration reduction optical element that reduces the aberration of the outgoing light that is obliquely incident on the objective lens, it is possible to reduce the deterioration of the focusing spot performance of the beam that is obliquely incident on the objective lens. Thus, an information recording / reproducing apparatus capable of high-speed parallel recording or high-speed parallel reproduction can be realized by using these multi-beams. In addition, since an expensive polarization component such as a Wollaston prism is not used, the optical system is simple and inexpensive.

以下本発明の実施の形態について、図面を参照しながら説明する。   Embodiments of the present invention will be described below with reference to the drawings.

（実施の形態１）
まず、本発明の実施の形態１の光学情報記録再生装置について、図１から図３までを用い、座標軸を図のようにとって詳細に説明する。 (Embodiment 1)
First, the optical information recording / reproducing apparatus according to the first embodiment of the present invention will be described in detail with reference to FIGS.

図１は本発明の実施の形態１における光学情報記録再生装置の基本構成と光の伝搬の様子を示す側面図、図２は本発明の実施の形態１の光学情報記録再生装置において、対物レンズへ斜入射する複数の出射光を示す説明図、図３（ａ）は本発明の実施の形態１の光学情報記録再生装置における斜入射収差低減光学素子の構造を示す側面図、図３（ｂ）は本発明の実施の形態１の光学情報記録再生装置における斜入射収差低減光学素子の構造を示す底面図、図３（ｃ）は本発明の実施の形態１の光学情報記録再生装置における斜入射収差低減光学素子の構造を示す底面図において等膜厚線を示す図である。等膜厚線は、地図の等高線のように、基板からある高さ（等膜厚面）での素子形状を点線で示したものであり、３次元的な形状を表すことができる。図２の光学情報記録再生装置は、基本的に図１の光学情報記録再生装置と同じものを図示しているが、対物レンズへ斜入射する複数の出射光を分かりやすく説明するために、ビームスプリッタや立ち上げミラー等の光学部品を省略して簡略化した構成である。そのため図２に示した対物レンズと情報記録媒体の座標系が図１の場合と異なる。   FIG. 1 is a side view showing a basic configuration of an optical information recording / reproducing apparatus according to Embodiment 1 of the present invention and how light is propagated, and FIG. 2 is an objective lens in the optical information recording / reproducing apparatus according to Embodiment 1 of the present invention. FIG. 3A is a side view showing the structure of the oblique incidence aberration reducing optical element in the optical information recording / reproducing apparatus according to Embodiment 1 of the present invention, and FIG. ) Is a bottom view showing the structure of the oblique incidence aberration reducing optical element in the optical information recording / reproducing apparatus of Embodiment 1 of the present invention, and FIG. 3 (c) is an oblique view of the optical information recording / reproducing apparatus of Embodiment 1 of the present invention. It is a figure which shows a uniform film thickness line in the bottom view which shows the structure of an incident aberration reduction optical element. The equal film thickness line represents the element shape at a certain height (equal film thickness surface) from the substrate with a dotted line, like a contour line on the map, and can represent a three-dimensional shape. The optical information recording / reproducing apparatus in FIG. 2 is basically the same as the optical information recording / reproducing apparatus in FIG. 1, but in order to easily understand a plurality of emitted lights incident obliquely on the objective lens, The configuration is simplified by omitting optical components such as a splitter and a rising mirror. Therefore, the coordinate system of the objective lens and the information recording medium shown in FIG. 2 is different from that in FIG.

本発明の光学情報記録再生装置は、独立に駆動（制御）可能な複数の発振部２３ａ〜２３ｃ（図１では発振部２３の数が３つの場合を図示）を備えた記録用または再生用の光源２０と、３次元的に記録可能な記録部３を有する情報記録媒体２１に上記発振部２３ａ〜２３ｃからの複数の出射光２２ａ〜２２ｃ（図１では出射光２２の数が３つの場合を図示）をそれぞれ集光する対物レンズ６と、上記情報記録媒体２１からの複数の反射光１７ａ〜１７ｃ、１７’ａ〜１７’ｃをそれぞれ検出する光検出器１９ａ〜１９ｃ、１９’ａ〜１９’ｃとを備え、上記光源２０と上記対物レンズ６の光路間に、上記対物レンズ６へ斜め入射する出射光８ｂ、８ｃに対応して、斜め入射により生じる収差（斜入射収差）を低減する斜入射収差低減光学素子２４を具備したことを特徴とする。   The optical information recording / reproducing apparatus of the present invention is used for recording or reproducing with a plurality of oscillation units 23a to 23c (in FIG. 1, the number of oscillation units 23 is shown) that can be independently driven (controlled). In the information recording medium 21 having the light source 20 and the recording unit 3 capable of three-dimensional recording, a plurality of outgoing lights 22a to 22c from the oscillation units 23a to 23c (in FIG. 1, the number of outgoing lights 22 is three). The objective lens 6 for condensing the light and the photodetectors 19a to 19c and 19'a to 19 for detecting the plurality of reflected lights 17a to 17c and 17'a to 17'c from the information recording medium 21, respectively. 'c, and reduces the aberration (oblique incident aberration) caused by the oblique incidence corresponding to the outgoing lights 8b and 8c obliquely incident on the objective lens 6 between the light paths of the light source 20 and the objective lens 6. Oblique incidence aberration reduction optical element 4, characterized by comprising a.

図２に示すように、発振部２３の数が複数（図１では３つ）になると、中央の発振部２３ａからの出射光２２ａは対物レンズ６に垂直入射するように配置できるため、対物レンズ６からの収束光７ａの焦点位置での集光スポットは斜入射収差の影響を受けずに良好に集光できるため（斜入射収差の補正必要なし）、記録時は、記録部３に形成した記録層１のトラック２８上に良好な記録ピット５ａを形成することができ、良好な再生も可能である。   As shown in FIG. 2, when the number of oscillating units 23 is plural (three in FIG. 1), the emitted light 22a from the central oscillating unit 23a can be arranged so as to be perpendicularly incident on the objective lens 6. Since the converging spot at the focal position of the convergent light 7a from No. 6 can be focused well without being affected by the oblique incidence aberration (no correction of the oblique incidence aberration is necessary), it is formed in the recording portion 3 at the time of recording. Good recording pits 5a can be formed on the track 28 of the recording layer 1, and good reproduction is also possible.

しかし、両端の発振部２３ｂ、２３ｃから出射された略平行光８ｂ、８ｃはどちらも対物レンズ６に斜入射する（それぞれの入射角θｂ、θｃ）ため、斜入射収差低減光学素子２４が無い場合は、収束光７ｂ、７ｃの集光スポットは斜入射収差の影響を受け、記録時は記録ピット５ｂ、５ｃはサイズが大きくなったり、ぼやけたりする等の悪化する傾向があり、再生信号の品質も悪くなりがちであったが、本発明の光学情報記録再生装置では、斜入射収差低減光学素子２４によりそのような収差を低減させて、記録部３に複数の良好な集光スポット５ａ〜５ｃを同時に形成することが可能で、出射光の数だけ（例えば、図１の構成では３倍）記録速度または再生速度は高速化できる。   However, since the substantially parallel lights 8b and 8c emitted from the oscillating units 23b and 23c at both ends are obliquely incident on the objective lens 6 (respectively incident angles θb and θc), there is no oblique incident aberration reducing optical element 24. The converging spots of the convergent lights 7b and 7c are affected by the oblique incident aberration, and the recording pits 5b and 5c tend to deteriorate such as becoming larger in size or blurred during recording. However, in the optical information recording / reproducing apparatus of the present invention, such an aberration is reduced by the oblique incident aberration reducing optical element 24, and a plurality of good condensing spots 5 a to 5 c are formed on the recording unit 3. Can be formed simultaneously, and the recording speed or reproduction speed can be increased by the number of outgoing lights (for example, three times in the configuration of FIG. 1).

従って、斜入射収差低減光学素子２４は、中央部の素子２４ａは斜入射補正が不必要なため無くても良く、少なくとも発振部２３の数より１つ少ない数だけアレイ化して設ければ良い。同一基板上にアレイ化することにより構造が安定になる。また、ウオラストンプリズムのような高価な偏光部品は使用しないため、光学系が簡単で、安価になるという効果もある。   Therefore, the oblique incident aberration reducing optical element 24 may be omitted because the central element 24a does not need the oblique incidence correction, and may be provided in an array of at least one less than the number of the oscillators 23. The structure is stabilized by arraying on the same substrate. Further, since expensive polarizing parts such as a Wollaston prism are not used, the optical system is simple and inexpensive.

なお、斜入射収差は、開口数ＮＡの大きい対物レンズ６に斜め入射するときにその大部分が発生するため、その発生分を補正すれば現実的にはそれで良い場合がほとんどである。しかしながらそれ以外にコリメータレンズ１６等の光学部品にも斜入射するため多少斜入射収差が生じる場合があり、全光学系の斜入射収差をトータルで補正すればより望ましい。   Incidentally, since most of the oblique incident aberration is generated when it is obliquely incident on the objective lens 6 having a large numerical aperture NA, it is practically sufficient if the generated amount is corrected. However, since it is also obliquely incident on optical components such as the collimator lens 16 and the like, there may be some oblique incidence aberration, and it is more desirable to correct the oblique incidence aberration of all optical systems in total.

実施の形態１の光学情報記録再生装置では、図１に示すように、光源２０の発振部２３から情報記録媒体２１までの光路中に、斜入射収差低減光学素子２４、光源２０の封止基板２５、コリメータレンズ１６、ビームスプリッタ１８、像回転プリズム１０、立ち上げミラー１２、球面収差補正素子１３、対物レンズ６が配置されている。   In the optical information recording / reproducing apparatus of the first embodiment, as shown in FIG. 1, in the optical path from the oscillation unit 23 of the light source 20 to the information recording medium 21, the oblique incident aberration reducing optical element 24 and the sealing substrate of the light source 20 are provided. 25, a collimator lens 16, a beam splitter 18, an image rotation prism 10, a rising mirror 12, a spherical aberration correction element 13, and an objective lens 6 are arranged.

復路となる、ビームスプリッタ１８から光検出器１９の光路には、フォーカス／トラック誤差信号検出素子１５、検出レンズ１１、情報記録媒体２１の層間クロストークを小さくするピンホールアレイ１４が配置されている。なお、図１では、コリメータレンズ１６から対物レンズ６までの光路、及びビームスプリッタ１８から検出レンズ１１までの光路においては、簡略化のため３つの出射光は同一の光線として図示されているが、実際は、図２に示すように（例えば８ａ〜８ｃ）、３つの出射光はそれぞれ分離している。   On the optical path from the beam splitter 18 to the photodetector 19 that is the return path, a focus / track error signal detection element 15, a detection lens 11, and a pinhole array 14 that reduces interlayer crosstalk of the information recording medium 21 are arranged. . In FIG. 1, in the optical path from the collimator lens 16 to the objective lens 6 and the optical path from the beam splitter 18 to the detection lens 11, the three outgoing lights are illustrated as the same light beam for simplicity. Actually, as shown in FIG. 2 (for example, 8a to 8c), the three outgoing lights are separated from each other.

情報記録媒体２１は、基板９上に、記録層１ａ〜１ｅと、中間層２ａ〜２ｄをそれぞれ複数層交互に堆積した記録部３（図１では記録層１は５層、中間層２は４層の場合を図示）と、表面に保護層４が設けられた構造である。記録層１を複数層積層することにより、３次元的な記録再生が可能で、記録容量をその層数の分だけ（例えば図１の構成では５倍）増加させることができる。   The information recording medium 21 includes a recording unit 3 in which a plurality of recording layers 1a to 1e and intermediate layers 2a to 2d are alternately deposited on a substrate 9 (in FIG. 1, the recording layer 1 has five layers and the intermediate layer 2 has four layers). In this case, the protective layer 4 is provided on the surface. By stacking a plurality of recording layers 1, three-dimensional recording / reproduction is possible, and the recording capacity can be increased by the number of layers (for example, five times in the configuration of FIG. 1).

図１に示すように、記録時においては、光源２０の３つの発振部２３ａ〜２３ｃからＹ軸方向への３つの出射光２２ａ〜２２ｃである、ピークパワーの比較的大きなパルスレーザ光（発散光）は、それぞれ、凸レンズ機能を有する斜入射収差低減光学素子２４ａ〜２４ｃ（図２、図３参照）に入射し、凸レンズ作用で発散角が若干緩和され、両端発振部２３ｂ、２３ｃからのそれぞれの出射光２２ｂと２２ｃは、対物レンズ６への斜入射で生じる斜入射収差を前もって逆向きに付加され、その後、対物レンズ６へ斜入射したときに生じる斜入射収差と打ち消しあい集光点での収差を低減することができる。   As shown in FIG. 1, at the time of recording, pulse laser light (diverged light) having a relatively large peak power, which is three emitted lights 22a to 22c in the Y-axis direction from the three oscillators 23a to 23c of the light source 20. ) Are incident on the oblique incidence aberration reducing optical elements 24a to 24c (see FIGS. 2 and 3) having a convex lens function, respectively, and the divergence angle is slightly relaxed by the convex lens action. The outgoing lights 22b and 22c are added in the opposite direction to the oblique incident aberration caused by the oblique incidence to the objective lens 6 and then cancel the oblique incident aberration caused when the oblique incident light is incident on the objective lens 6. Aberration can be reduced.

斜入射収差には、具体的に、コマ収差、像面湾曲に伴うデフォーカス、非点収差の３種類の収差成分があるが、それぞれのＲＭＳ波面収差（以下波面収差と記載）の許容範囲を１０ｍλとして収差低減を行った。最悪の場合で、３つとも１０ｍλの波面収差が生じた場合はその合計の斜入射収差は１７ｍλ（２乗平均で計算）となる。これより大きくなると中央の集光スポットに比べて、両端の集光スポットの中心強度は３％以上低下するため、記録感度は不揃いとなり好ましくないことが分かった。   The oblique incidence aberration specifically includes three types of aberration components: coma aberration, defocus due to curvature of field, and astigmatism, but each RMS wavefront aberration (hereinafter referred to as wavefront aberration) has an allowable range. The aberration was reduced to 10 mλ. In the worst case, when wavefront aberration of 10 mλ is generated in all three cases, the total oblique incident aberration is 17 mλ (calculated by root mean square). If it is larger than this, the central intensity of the focused spots at both ends is reduced by 3% or more compared to the focused spot at the center, and it has been found that the recording sensitivity becomes uneven and is not preferable.

それぞれの斜入射収差低減光学素子２４ａ〜２４ｃが、斜入射収差を補正する機能があれば良いが、特にそれに加えて凸レンズ機能を有することにより、各出射光２２ａ〜２２ｃの発散角が小さくなり、対物レンズ６に入射する光８ａ〜８ｃの利用効率が向上する。なお、凸レンズ機能がない場合、斜入射収差低減光学素子２４ａは省略することができ、２４ｂと２４ｃのみで良い。なお、中央の素子２４ａには斜入射収差低減の機能は特に必要がないが、一般化するために斜入射収差低減光学素子の１つとして記載している。   Each of the oblique incident aberration reducing optical elements 24a to 24c only needs to have a function of correcting the oblique incident aberration, and in particular, by having a convex lens function, the divergence angles of the respective outgoing lights 22a to 22c are reduced, The utilization efficiency of the light 8a-8c which injects into the objective lens 6 improves. When there is no convex lens function, the oblique incident aberration reducing optical element 24a can be omitted, and only 24b and 24c are required. The central element 24a is not particularly required to have the function of reducing the oblique incidence aberration, but is described as one of the oblique incidence aberration reducing optical elements for generalization.

その後、３つの出射光２２ａ〜２２ｃとも、コリメータレンズ１６により、略平行光となり、ビーム分岐素子であるビームスプリッタ１８を透過して、像回転プリズム１０である公知のドーブプリズムに入射する。像回転プリズム１０は、入射光線が底面で全反射するような台形形状をしており、後述する光検出器１９’ａ〜１９’ｃで検出された３つのトラック誤差信号に基づき、アクチュエータ等を用いてＺＸ面内での回転を行い、３つの集光スポットが情報記録媒体２１の記録部３の記録層１に形成した各トラック２８上に乗るように調整される。   Thereafter, the three emitted lights 22 a to 22 c are substantially collimated by the collimator lens 16, pass through the beam splitter 18 that is a beam branching element, and enter a known dove prism that is the image rotation prism 10. The image rotation prism 10 has a trapezoidal shape so that incident light rays are totally reflected on the bottom surface. Based on three track error signals detected by photodetectors 19′a to 19′c, which will be described later, an actuator or the like is provided. Using the rotation in the ZX plane, the three focused spots are adjusted so as to ride on the tracks 28 formed on the recording layer 1 of the recording unit 3 of the information recording medium 21.

立ち上げミラー１２によって光路を−Ｚ軸方向に折り曲げられた３つの略平行光８（図２では８ａ〜８ｃ）は、球面収差補正素子１３を通過して、対物レンズ６によって、情報記録媒体２１の保護層４を通過して記録部３の所望の記録層１ｃのトラック２８上に集光し（収束光７ａ〜７ｃ）、記録層１の層数が、例えば、８層以下と少ない場合は、記録材料の屈折率と消衰係数（吸収係数）を変化させて通常の１光子吸収記録で、また、記録層１の層数が、例えば８層より多い場合は２光子吸収または多光子吸収（３光子吸収以上）、プラズマ記録等のような非線形現象を用いて、記録材料の光学定数のうち望ましくは屈折率のみを変化させて、記録ピット５ａ〜５ｃの列が記録される。   Three substantially parallel light beams 8 (8a to 8c in FIG. 2) whose optical path is bent in the −Z-axis direction by the rising mirror 12 pass through the spherical aberration correction element 13 and are information recording medium 21 by the objective lens 6. When the number of layers of the recording layer 1 is as small as 8 or less, for example, the light is condensed on the track 28 of the desired recording layer 1c of the recording unit 3 (converged light 7a to 7c). In normal 1-photon absorption recording by changing the refractive index and extinction coefficient (absorption coefficient) of the recording material, and when the number of recording layers 1 is more than 8, for example, 2-photon absorption or multi-photon absorption Using a non-linear phenomenon such as plasma recording (3 photon absorption or more), preferably only the refractive index of the optical constants of the recording material is changed, and the rows of recording pits 5a to 5c are recorded.

なお、図１に示した情報記録媒体２１は複数の記録層１と中間層３を交互に設けた積層構造であるが、それぞれの厚さは、例えば、基板９は１ｍｍ、各記録層１は数１０ｎｍ〜数１００ｎｍ、各中間層２は３〜１０μｍである。記録部３が、数１００μｍ程度の厚い記録層１のみ（中間層２なし）のいわゆるバルクの構造でも、光軸（図１ではＺ）方向に３次元的に記録可能であるため、そのような構造でも良い。   The information recording medium 21 shown in FIG. 1 has a laminated structure in which a plurality of recording layers 1 and intermediate layers 3 are alternately provided. The thickness of each of the recording layers 1 is, for example, 1 mm for the substrate 9 and each recording layer 1 is Several tens of nm to several hundreds of nm, and each intermediate layer 2 is 3 to 10 μm. The recording unit 3 can record three-dimensionally in the direction of the optical axis (Z in FIG. 1) even in a so-called bulk structure having only a thick recording layer 1 (no intermediate layer 2) of about several hundred μm. Structure may be sufficient.

２光子または多光子吸収、プラズマ記録等の非線形現象を利用して記録を行う場合では、例えば、記録波長のちょうど半分の波長（２光子吸収の場合）で吸収がある記録材料を記録層１として用いることにより、例えば、数１００ｍＷ〜数Ｗ以上の比較的ピークパワーの高い、例えば１００フェムト秒〜１００ナノ秒のパルス幅の小さい記録光を照射すると、対物レンズ６により集光された光のパワ密度の高い部分（集光点）のみが波長が半分になった効果が生じて、記録材料に吸収が起こり、記録ピット５が記録される。本実施の形態で用いた半導体レーザ光源２０では、超短パルス化が困難なため、記録時は記録ピットの長さ（記録マーク）に応じて、パルス幅を１ナノ秒から１００ナノ秒の間で変化させて（例えば、記録マークが長いほどパルス幅を長くして）記録光を出射した。非線形記録では、このように集光点のみで吸収が生じるため、深い領域の記録層にも光がそれほど減衰されないため、超多層光メモリのように記録層１の多いまたは記録部１の厚い３次元光メモリに適している。   When recording is performed using a nonlinear phenomenon such as two-photon or multi-photon absorption or plasma recording, for example, a recording material that absorbs at a half wavelength of the recording wavelength (in the case of two-photon absorption) is used as the recording layer 1. By using, for example, recording light having a relatively high peak power of several hundred mW to several W or more, for example, 100 femtoseconds to 100 nanoseconds and a small pulse width, the power of the light collected by the objective lens 6 is increased. Only the portion with high density (condensing point) has the effect of halving the wavelength, absorption occurs in the recording material, and the recording pits 5 are recorded. In the semiconductor laser light source 20 used in the present embodiment, since it is difficult to make an ultrashort pulse, during recording, the pulse width is between 1 nanosecond and 100 nanoseconds depending on the length of the recording pit (recording mark). (For example, the longer the recording mark, the longer the pulse width) and the recording light was emitted. In non-linear recording, absorption occurs only at the condensing point as described above, and thus light is not attenuated so much even in a deep recording layer. Therefore, there are many recording layers 1 or a thick three-dimensional recording unit 1 as in an ultra-multilayer optical memory. Suitable for optical memory.

感光材料としては、８層以下と記録層１が少ない場合には１光子吸収記録が可能なため相変化材料や感光色素等を用いることができる。記録層１が８層より多い場合では非線形記録が適しているため、フォトポリマーや、ジアリールエテン等のフォトクロミック材料等の有機色素、ＺｎＯ等の超微粒子を混入した樹脂膜、ＺｎＳ、ＴｅＯ２膜等が感光材料として適しており、屈折率変化のみを利用することにより光の吸収損失を減らすことができる。記録光の照射の仕方により、屈折率変化量を制御できるが、数Ｗ〜数１０ｋＷと比較的ピークパワーの高いパルス光を用いると、ボイドと言われる空のピットを記録することも可能である。ボイドの場合は、屈折率が１であるので、記録膜の屈折率が、例えば、１．７の場合、屈折率変化量はΔｎ＝−０．７と大きくなるため、コントラスト良く信号を再生できるという効果がある。 As the photosensitive material, when there are less than eight layers and the recording layer 1 is small, one-photon absorption recording is possible, so that a phase change material, a photosensitive dye, or the like can be used. When there are more than 8 recording layers, nonlinear recording is suitable. Therefore, a photopolymer, an organic dye such as a photochromic material such as diarylethene, a resin film in which ultrafine particles such as ZnO are mixed, a ZnS, TeO 2 film, etc. It is suitable as a photosensitive material, and light absorption loss can be reduced by using only the refractive index change. Although the amount of change in the refractive index can be controlled by the manner of irradiation of the recording light, it is also possible to record empty pits called voids when using pulsed light having a relatively high peak power of several watts to several tens of kW. . In the case of a void, since the refractive index is 1, when the refractive index of the recording film is 1.7, for example, the amount of change in the refractive index is as large as Δn = −0.7, so that a signal can be reproduced with good contrast. There is an effect.

再生時においては、同じ光源２０の発振部２３ａ〜２３ｃから低パワの連続発振のレーザ光を出射光２２ａ〜２２ｃ（簡単化のため記録時と再生時の光線は同じ記号を使用）として出射させて、記録時の場合と同じ経路を辿るが、この場合も、それぞれ、斜入射収差低減光学素子２４ａ〜２４ｃにより、両端の出射光２２ｂと２２ｃは、対物レンズ６への斜め入射で生じるコマ収差やデフォーカス、非点収差の斜入射収差を逆向きに付加される。前もって収差を付加された３つの出射光８ａ〜８ｃは、対物レンズ６によって情報記録媒体２１の記録部３の所望の記録層１ｃの記録ピット５ａ〜５ｃにそれぞれ斜入射収差が低減されて良好に集光（収束光７ａ〜７ｃ）される。   During reproduction, low-power continuous oscillation laser light is emitted from the oscillating units 23a to 23c of the same light source 20 as emitted light 22a to 22c (for the sake of simplicity, the same symbol is used for recording and reproduction). Then, the same path as that at the time of recording is followed, but also in this case, the outgoing light 22b and 22c at both ends are caused by the oblique incidence to the objective lens 6 by the oblique incidence aberration reducing optical elements 24a to 24c, respectively. In addition, defocus and astigmatism oblique incidence aberrations are added in the opposite direction. The three outgoing lights 8a to 8c to which aberrations have been added in advance are satisfactorily reduced by the objective lens 6 so that the oblique incident aberrations are reduced to the recording pits 5a to 5c of the desired recording layer 1c of the recording unit 3 of the information recording medium 21, respectively. It is condensed (converged light 7a-7c).

記録ピット５ａ〜５ｃによって反射されたレーザ光７ａ〜７ｃは、逆方向に折り返し、対物レンズ６、球面収差補正素子１３、立ち上げミラー１２、像回転プリズム１０を順に通過し、ビームスプリッタ１８により光軸をＺ軸方向に曲げられ、回折型フォーカス／トラック誤差信号検出素子１５によって、それぞれの出射光に対して少なくとも２つの光に分岐させて、検出レンズ１１により収束光１７ａ〜１７ｃ（０次回折光）、１７’ａ〜１７’ｃ（１次回折光）となる。収束光１７ａ〜１７ｃは、ピンホールアレイのそれぞれのピンホール１４ａ〜１４ｃを通過させて、光検出器１９ａ〜１９ｃにより再生信号光して検出される。フォーカス／トラック誤差信号となる収束光１７’ａ〜１７’ｃは、ピンホールを通過させずに、別の光検出器１９’ａ〜１９’ｃで検出される。   The laser beams 7a to 7c reflected by the recording pits 5a to 5c are turned in the reverse direction, pass through the objective lens 6, the spherical aberration correction element 13, the rising mirror 12, and the image rotating prism 10 in this order, and are then emitted by the beam splitter 18. The axis is bent in the Z-axis direction, and the diffractive focus / track error signal detection element 15 divides each output light into at least two lights, and the detection lens 11 converges light 17a to 17c (0th order diffracted light). ), 17′a to 17′c (first-order diffracted light). The convergent lights 17a to 17c pass through the respective pinholes 14a to 14c of the pinhole array and are detected as reproduction signal lights by the photodetectors 19a to 19c. The convergent lights 17'a to 17'c, which become focus / track error signals, are detected by other photodetectors 19'a to 19'c without passing through the pinholes.

各ピンホール１４ａ〜１４ｃが、それぞれの検出収束光１７ａ〜１７ｃのほぼ焦点の位置に設置するようにピンホールアレイを設置したが、ピンホールアレイにすることにより各ピンホールの間隔が常に一定となり安定構造になる。また各ピンホール１４ａ〜１４ｃを通すことにより、所望の記録層１ｃの光軸方向の上下の層１ａ、１ｂ、１ｄ、１ｅからの不要反射光であるクロストーク（層間クロストーク）光が各ピンホール１４ａ〜１４ｃ外に分布し、それらの光は各ピンホール１４ａ〜１４ｃ内に入らなくなるため、層間クロストークを減少させる効果がある。フォーカス／トラック誤差信号は、ピンホールを通過させない構成により、非点収差法や３ビームトラッキング法のような従来方法で、それぞれフォーカスやトラック誤差信号を検出することができる。   The pinhole array is installed so that the pinholes 14a to 14c are arranged at substantially the focal positions of the respective detection convergent lights 17a to 17c. However, by using the pinhole array, the interval between the pinholes is always constant. It becomes a stable structure. Further, by passing through the pinholes 14a to 14c, crosstalk (interlayer crosstalk) light, which is unnecessary reflected light from the upper and lower layers 1a, 1b, 1d, and 1e in the optical axis direction of the desired recording layer 1c, is transmitted to each pin. Since the light is distributed outside the holes 14a to 14c and the light does not enter the pin holes 14a to 14c, there is an effect of reducing interlayer crosstalk. A focus / track error signal can be detected by a conventional method such as an astigmatism method or a three-beam tracking method, with a configuration in which the focus / track error signal does not pass through the pinhole.

フォーカス／トラック誤差信号検出素子は、回折型の光学素子とすることにより製造が楽で低コスト化ができ、０次回折光を再生信号とすることによりピンホール１４への入射の光軸は垂直に近いため入射特性が良く、また１次回折光のみをフォーカス／トラック誤差信号とする構成により光検出器１９’の構成が簡単になる。   The focus / track error signal detection element can be manufactured easily and at low cost by using a diffractive optical element, and the optical axis of incidence on the pinhole 14 can be made vertical by using 0th-order diffracted light as a reproduction signal. Due to the proximity, the incident characteristics are good, and the configuration of the photodetector 19 ′ is simplified by the configuration in which only the first-order diffracted light is used as the focus / track error signal.

検出レンズ１１の焦点距離は、例えば３３ｍｍであり、光検出器１９側でのエアリーディスク径は、例えば９．６μｍとなる。また、ピンホール１４の代わりに、光検出器１９ａ〜１９ｃの受光部がピンホール径の大きさを有する微小光検出器で、検出収束光１７ａ〜１７ｃをそれぞれ検出するようにしても同様の効果が得られる。   The focal length of the detection lens 11 is, for example, 33 mm, and the Airy disk diameter on the photodetector 19 side is, for example, 9.6 μm. Further, the same effect can be obtained by detecting the detection convergent lights 17a to 17c with the light detectors of the photodetectors 19a to 19c having a pinhole diameter instead of the pinhole 14, respectively. Is obtained.

本実施の形態では、ピンホール１４ａ〜１４ｃの大きさをそれぞれの収束光１７ａ〜１７ｃのエアリーディスク径の５倍以下、望ましくは１〜３倍程度にすることによって、例えば、記録層１の層間隔が３〜５μｍで問題ないレベル（層間クロストーク量≦３０ｄＢ）まで再生信号の品質を向上させることが可能であった。ただし、ピンホール１４の大きさを小さくすると、記録層１の間隔をより小さくすることが可能であるが、小さくし過ぎる（エアリーディスク径未満）と、ピンホール１４に入る光量が大幅に減少したり、環境温度により光学系が歪んで、収束光１７ａ〜１７ｃがピンホール１４ａ〜１４ｃの中心からそれぞれずれることもあるため、それらを考慮する必要があった。   In the present embodiment, the size of the pinholes 14a to 14c is set to 5 times or less, preferably about 1 to 3 times the Airy disk diameter of the respective convergent lights 17a to 17c, for example, the layer of the recording layer 1 It was possible to improve the quality of the reproduced signal up to a level (interlayer crosstalk amount ≦ 30 dB) with an interval of 3 to 5 μm. However, if the size of the pinhole 14 is reduced, the interval between the recording layers 1 can be made smaller. However, if the pinhole 14 is too small (less than the Airy disc diameter), the amount of light entering the pinhole 14 is greatly reduced. In addition, the optical system may be distorted by the environmental temperature, and the convergent lights 17a to 17c may be shifted from the centers of the pinholes 14a to 14c, respectively.

本実施の形態１の光学情報記録再生装置では、光源２０は、実質的に同一波長の出射光２２ａ〜２２ｃを発する複数の発振部２３ａ〜２３ｃを有する半導体レーザで、複数の発振部２３ａ〜２３ｃは同一基板上に形成されている集積構造である。この集積構造により、光学情報記録再生装置の構成が簡単化できるとともに、発振部２３ａ〜２３ｃの間隔は半導体のフォトリソグラフィ技術により精度良く構成でき、また光学特性も同一になるという効果がある。光源２０の複数の発振部２３ａ〜２３ｃは、記録時または再生時に同時に独立駆動し、複数の情報を情報記録媒体２１の記録部３に同時に記録または再生を行うことができ、その結果、高速記録または高速再生が可能となる。さらに、光源２０の発振部２３ａ〜２３ｃの数は３以上の奇数とすることにより、中央の発振部２３ａから出射された略平行光８ａは対物レンズ６に垂直入射（入射角は０°）することが可能となり、最も優れた集光特性が発揮できる。中央からずれた周辺の発振部２３ｂと２３ｃからのそれぞれの出射光８ｂと８ｃは、対物レンズ６への入射角θｂとθｃは同じになり、対称構造となりバランスがとれる。   In the optical information recording / reproducing apparatus of the first embodiment, the light source 20 is a semiconductor laser having a plurality of oscillating units 23a-23c that emit emitted lights 22a-22c having substantially the same wavelength, and a plurality of oscillating units 23a-23c. Is an integrated structure formed on the same substrate. With this integrated structure, the configuration of the optical information recording / reproducing apparatus can be simplified, and the intervals between the oscillating units 23a to 23c can be configured with high accuracy by a semiconductor photolithography technique, and the optical characteristics are also the same. The plurality of oscillation units 23a to 23c of the light source 20 can be independently driven at the same time during recording or reproduction, and can simultaneously record or reproduce a plurality of information on the recording unit 3 of the information recording medium 21, resulting in high-speed recording. Or high-speed playback is possible. Further, by setting the number of the oscillating units 23a to 23c of the light source 20 to an odd number of 3 or more, the substantially parallel light 8a emitted from the central oscillating unit 23a is perpendicularly incident on the objective lens 6 (incident angle is 0 °). And the most excellent light collecting characteristics can be exhibited. The light beams 8b and 8c emitted from the peripheral oscillators 23b and 23c shifted from the center have the same incident angles θb and θc to the objective lens 6 and are symmetrical and balanced.

また、光源２０は、記録用と再生用を兼ねており、出射光の波長は、例えば、０．４０５μｍで、記録時は高パワのパルス光を出射し、再生時には低パワの連続光を照射する。光源２０は記録用と再生用を兼ねることにより、構成が簡単になる。光源の波長は、情報記録媒体２１の記録材料に合わせて、決めればよい。   The light source 20 is used for both recording and reproduction. The wavelength of the emitted light is, for example, 0.405 μm, and emits high-power pulsed light during recording, and irradiates low-power continuous light during reproduction. To do. Since the light source 20 serves both for recording and for reproduction, the configuration is simplified. The wavelength of the light source may be determined according to the recording material of the information recording medium 21.

斜入射収差低減光学素子２４は、発振部２３の近くに配置した、光源２０を封止する封止基板２５の表面または裏面（図１には裏面の場合を図示）に、各出射光２２ａ〜２２ｃに対応するようにアレイ化して形成されている（図２、図３には斜入射収差低減光学素子２４は３つの素子２４ａ〜２４ｃで構成されている場合を図示）。封止基板２５の表面または裏面に斜入射収差低減光学素子２４ａ〜２４ｃを同時に形成（同一基板上に形成）する構成により、構成が簡単になり構造が安定化する。特に封止基板２５の裏面に形成すれば、斜入射収差低減光学素子２４が内蔵される構成となり素子２４の損傷も防止することができる。   The oblique incident aberration reducing optical element 24 is arranged on the front surface or the back surface (the back surface is shown in FIG. 1) of the sealing substrate 25 that seals the light source 20 disposed near the oscillation unit 23. The oblique incident aberration reducing optical element 24 is composed of three elements 24a to 24c (illustrated in FIGS. 2 and 3). The configuration in which the oblique incident aberration reducing optical elements 24a to 24c are simultaneously formed (formed on the same substrate) on the front or back surface of the sealing substrate 25 simplifies the configuration and stabilizes the structure. In particular, if formed on the back surface of the sealing substrate 25, the oblique incident aberration reducing optical element 24 is built in, and damage to the element 24 can be prevented.

一般に、発振部２３からの出射光２２は発散波であり、複数の発振部２３ａ〜２３ｃからの出射光２２ａ〜２２ｃは、ファーフィールドにおいては重なり合う。例えば、発振部２３ａ〜２３ｃ間の距離をｄ、出射光２２ａ〜２２ｃの片側の発散角をθとすると、出射光同士が重なるまでの距離は、ｌ＝ｄ／（２ｔａｎθ）となるため、発振部２３と斜入射収差低減光学素子２４の間隔をｌ以下にすることによって、発振部２３ａ〜２３ｃからのそれぞれの出射光２２ａ〜２２ｃに対して、ほとんど重なることなく、良好に収差補正が可能となる。例えば、ｄ＝１００μｍ、θ＝８°ならｌ＝３５６μｍであり、ｌは小さいため斜入射収差低減光学素子２４は光源２０に内蔵しやすいと言える。   In general, the emitted light 22 from the oscillating unit 23 is a divergent wave, and the emitted lights 22a to 22c from the plurality of oscillating units 23a to 23c overlap in the far field. For example, if the distance between the oscillators 23a to 23c is d and the divergence angle on one side of the emitted lights 22a to 22c is θ, the distance until the emitted lights overlap is l = d / (2 tan θ). By making the distance between the portion 23 and the oblique incidence aberration reducing optical element 24 equal to or less than 1, the aberration can be corrected satisfactorily with almost no overlap with the emitted lights 22a to 22c from the oscillation portions 23a to 23c. Become. For example, if d = 100 μm and θ = 8 °, l = 356 μm, and since l is small, it can be said that the oblique incidence aberration reducing optical element 24 is easily built in the light source 20.

次に、斜入射収差補正素子２４が配置されていない場合に生じる斜入射収差について説明する。例えば、光源の波長がλ＝０．４０５μｍ、波長コリメータレンズ１６の焦点距離がｆｃ＝１８ｍｍ、対物レンズ６の開口数はＮＡ＝０．８５、焦点距離がｆｏ＝１．３ｍｍ（倍率ｆｃ／ｆｏ＝１３．８倍）の場合について説明する。なお、同一基板上に形成された光源の発振部２３の間隔は、熱の影響を受けるため、実際の値は最小値でせいぜいｄ＝５０〜１００μｍ程度である。   Next, the oblique incidence aberration that occurs when the oblique incidence aberration correction element 24 is not disposed will be described. For example, the wavelength of the light source is λ = 0.405 μm, the focal length of the wavelength collimator lens 16 is fc = 18 mm, the numerical aperture of the objective lens 6 is NA = 0.85, and the focal length is fo = 1.3 mm (magnification fc / fo = 13.8 times) will be described. The interval between the light source oscillators 23 formed on the same substrate is affected by heat, so the actual value is a minimum value of d = 50 to 100 μm at most.

図１に示すように発振部２３の間隔がｄ＝１００μｍでその数が３つの場合、両端発振部２３ｂ、２３ｃからの平行光８ｂ、８ｃは対物レンズ６へ斜入射し、その斜入射角はθｂ＝θｃ＝０．３２°となる。その結果、それに対応する収束光７ｂと７ｃは焦点で、例えば、トータルの斜入射収差は１５ｍλの波面収差が生じて集光スポットがその分劣化することが分かった。波面収差１５ｍλの内訳は、コマ収差１０ｍλ、非点収差４ｍλ、デフォーカス９ｍλであった。現実的な収差の許容範囲はそれぞれの収差で１０ｍλであったので、収差としてはぎりぎり許容範囲であったが、他の部分から球面収差等も生じている可能性があり、収差の低減はマージンが増加するため好ましい。収差の中では、コマ収差が最も大きく、デフォーカスが同程度で、非点収差が半分以下である。従って、この場合の収差補正では、コマ収差とデフォーカスが主に生じるので、斜入射収差低減光学素子によりその２つの成分を低減すれば実質的に問題ない。   As shown in FIG. 1, when the interval between the oscillating units 23 is d = 100 μm and the number thereof is three, the parallel lights 8b and 8c from the both-end oscillating units 23b and 23c are obliquely incident on the objective lens 6, and the oblique incident angle is θb = θc = 0.32 °. As a result, it was found that the corresponding convergent lights 7b and 7c are focal points, for example, the total oblique incident aberration has a wavefront aberration of 15 mλ and the focused spot is deteriorated accordingly. The breakdown of the wavefront aberration of 15 mλ was coma aberration of 10 mλ, astigmatism of 4 mλ, and defocus of 9 mλ. Since the actual allowable range of aberration was 10 mλ for each aberration, the aberration was a marginal allowable range. However, spherical aberration or the like may be generated from other parts, and the reduction of aberration is a margin. Is preferable because of an increase. Among aberrations, coma is the largest, defocus is about the same, and astigmatism is less than half. Accordingly, in the aberration correction in this case, coma and defocus mainly occur. Therefore, there is substantially no problem if the two components are reduced by the oblique incident aberration reducing optical element.

次に、斜入射角が大きくなり、例えば、θｂ＝θｃ＝０．６４°となる場合について述べる。この場合は、発振部２３の間隔が２００μｍで発振部２３の個数が３つの場合のその両端部からの出射光に対する場合、または発振部２３の間隔が１００μｍで発振部２３の個数が５つの場合のその両端部からの出射光に対する場合に相当する。このときは、それに対応する両端の収束光は焦点でトータルの波面収差４６ｍλだけ斜入射収差が生じることが分かった。その波面収差４６ｍλの内訳は、コマ収差２１ｍλ、非点収差１４ｍλ、デフォーカス３４ｍλであり、この場合、デフォーカスが最も大きく、コマ収差がその次で、非点収差が最小である。従って、この場合の斜入射収差低減光学素子による収差補正では、デフォーカスとコマ収差の低減は必須であり、非点収差も１０ｍλを越えているので低減する方が好ましい。   Next, a case where the oblique incident angle is increased, for example, θb = θc = 0.64 ° will be described. In this case, when the interval between the oscillating units 23 is 200 μm and the number of the oscillating units 23 is three, when the light is emitted from both ends, or when the interval between the oscillating units 23 is 100 μm and the number of the oscillating units 23 is five. This corresponds to the case of the light emitted from both end portions. At this time, it was found that the converging light at both ends corresponding to it has an oblique incident aberration at the focal point by a total wavefront aberration of 46 mλ. The breakdown of the wavefront aberration 46mλ is coma aberration 21mλ, astigmatism 14mλ, and defocus 34mλ. In this case, defocus is the largest, coma is the next, and astigmatism is the smallest. Therefore, in the aberration correction by the oblique incidence aberration reducing optical element in this case, it is essential to reduce defocus and coma, and it is preferable to reduce astigmatism because it exceeds 10 mλ.

さらに、斜入射角が大きくなり、例えば、θｂ＝θｃ＝０．９６°となる場合について述べる。この場合は、発振部２３の間隔が４００μｍで発振部２３の個数が３つの場合の両端部からの出射光に対する場合、または発振部２３の間隔が２００μｍで発振部の個数が５つの場合の両端部からの出射光に対する場合、または発振部２３の間隔が１００μｍで発振部２３の個数が７つの場合の両端部からの出射光に対する場合に相当する。このときは、それに対応する両端の収束光は焦点でトータルの波面収差９７ｍλだけ斜入射収差が生じることが分かった。その波面収差９７ｍλの内訳は、コマ収差３４ｍλ、非点収差３３ｍλ、デフォーカス７８ｍλであり、この場合いずれの収差も１０ｍλを大きく越えているため、斜入射収差低減光学素子により、すべての成分を低減する必要がある。   Further, a case where the oblique incident angle is increased, for example, θb = θc = 0.96 ° will be described. In this case, both ends when the interval between the oscillating units 23 is 400 μm and the number of the oscillating units 23 is three, and the light is emitted from both ends, or when the interval between the oscillating units 23 is 200 μm and the number of oscillating units is five. This corresponds to the case of light emitted from both ends, or the case of light emitted from both ends when the interval between the oscillators 23 is 100 μm and the number of oscillators 23 is seven. At this time, it was found that the convergent light at both ends corresponding to the incident light has oblique incidence aberrations at the focal point by a total wavefront aberration of 97 mλ. The breakdown of the wavefront aberration of 97 mλ is coma aberration 34 mλ, astigmatism 33 mλ, and defocus 78 mλ. In this case, all aberrations greatly exceed 10 mλ, and thus all components are reduced by the oblique incident aberration reducing optical element. There is a need to.

逆に、斜入射角が小さくなり、例えば、θｂ＝θｃ＝０．１６°となる場合について述べる。この場合は、発振部２３の間隔が５０μｍで発振部２３の個数が３つの場合の両端部からの出射光に対する場合に相当する。このときは、それに対応する両端の収束光は焦点でトータルの波面収差６ｍλだけ斜入射収差が生じることが分かった。その波面収差６ｍλの内訳は、コマ収差５ｍλ、非点収差１ｍλ、デフォーカス２ｍλであり、この場合いずれの収差も１０ｍλ以下であるため特に収差低減の必要はないが、斜入射収差低減光学素子により低減するとすれば、コマ収差のみで良く、その結果マージンはその分増加する。   Conversely, a case where the oblique incident angle becomes small, for example, θb = θc = 0.16 ° will be described. This case corresponds to the case of light emitted from both ends when the interval between the oscillating units 23 is 50 μm and the number of oscillating units 23 is three. At this time, it was found that the converging light at both ends corresponding to it has an oblique incident aberration at the focal point by a total wavefront aberration of 6 mλ. The breakdown of the wavefront aberration 6mλ is coma aberration 5mλ, astigmatism 1mλ, and defocus 2mλ. In this case, since all aberrations are 10mλ or less, it is not necessary to reduce the aberration. If it is reduced, only coma aberration is sufficient, and as a result, the margin increases accordingly.

以上の考察結果から、コマ収差は斜入射角に比例し、非点収差とデフォーカスは斜入射角の２乗に比例することが分かり、斜入射角が、例えば０．１６°と非常に小さいときは、斜入射収差低減光学素子２４はせいぜいコマ収差のみを補正するだけで効果があり、例えば０．３２°と斜入射角がそれより大きくなった場合は、コマ収差とデフォーカスの２つ補正するだけで十分効果があり、さらに０．６４°、０．９６°と斜入射角が大きくなってきた場合は、コマ収差とデフォーカスと非点収差の３つとも補正する必要があることが分かった。従って、斜入射収差低減光学素子２４の形状は上記の考察に基づいて、斜入射角に合わせて、収差成分を選んで適切に低減すれば効果がある。   From the above consideration results, it can be seen that coma is proportional to the oblique incident angle, and astigmatism and defocus are proportional to the square of the oblique incident angle. The oblique incident angle is very small, for example, 0.16 °. In some cases, the oblique incident aberration reducing optical element 24 is effective only by correcting only the coma aberration. For example, when the oblique incident angle is larger than 0.32 °, the coma aberration and the defocus are two. Correcting the effect is sufficient, and if the angle of incidence is 0.64 ° or 0.96 °, it is necessary to correct all three coma, defocus, and astigmatism. I understood. Therefore, the shape of the oblique incident aberration reducing optical element 24 is effective if the aberration component is selected and appropriately reduced in accordance with the oblique incident angle based on the above consideration.

次に、斜入射収差低減光学素子２４の形状について説明する。図３に示すように、アレイ化されて配置された斜入射収差低減光学素子２４ａ〜２４ｃは、対物レンズ６への入射角に応じた形状をしている。入射角が０である出射光８ａに対応しては、斜入射収差を補正する必要はないため、凸レンズ機能のみを有した凸レンズ形状をしている。斜入射収差低減光学素子２４ａの厚さをＬ１、基板２５の裏面をＹ座標の原点、素子２４ａの中央位置（レンズ頂点の位置）を座標系ＺＸａの原点にして考えると、素子２４ａ形状を表す−Ｙ座標（高さ）が等しい等膜厚面での点線で示した等膜厚線２６ａの形状は円になり、その直径は、−Ｙ座標（高さ）が大きくなるほど小さくなる値である。なお、Ｘ＝０におけるＹＺ面での素子２４ａの形状は実質的に放物線状となり、良好に凸レンズ機能を有する。また、厚さＬを大きくして曲率半径を小さくすると凸レンズの焦点距離は短くなり、逆にＬを小さくして曲率半径を大きくするとその焦点距離は長くでき、デフォーカスの低減に有用である。   Next, the shape of the oblique incidence aberration reducing optical element 24 will be described. As shown in FIG. 3, the oblique incident aberration reducing optical elements 24 a to 24 c arranged in an array have a shape corresponding to the incident angle to the objective lens 6. Corresponding to the outgoing light 8a having an incident angle of 0, it is not necessary to correct the oblique incident aberration, so that it has a convex lens shape having only a convex lens function. Considering the thickness of the oblique incident aberration reducing optical element 24a as L1, the back surface of the substrate 25 as the origin of the Y coordinate, and the center position (position of the lens apex) of the element 24a as the origin of the coordinate system ZXa, the shape of the element 24a is represented. The shape of the equal film thickness line 26a indicated by the dotted line on the equal film thickness surface having the same −Y coordinate (height) is a circle, and the diameter thereof is smaller as the −Y coordinate (height) is larger. . Note that the shape of the element 24a on the YZ plane at X = 0 is substantially parabolic and has a good convex lens function. Further, when the thickness L is increased and the curvature radius is decreased, the focal length of the convex lens is shortened, and conversely, when L is decreased and the curvature radius is increased, the focal length can be increased, which is useful for reducing defocus.

アレイ化した中央部以外の斜入射収差低減光学素子２２ｂ、２２ｃは、等膜厚面上での等膜厚線２６ｂ、２６ｃが円となる凸レンズ形状であり、その円の中心位置は等膜厚面が高くなるに従い、対物レンズ６への斜め入射の角度に依存して中央部の斜入射収差低減光学素子２４ａのセンター（座標系ＺＸａの原点）方向に徐々に移動する構造をしている。座標系ＺＸｂ、ＺＸｃの原点からの中心位置のシフト量は、等膜厚面の高さとｔａｎθｂの積、等膜厚面の高さとｔａｎθｃの積にそれぞれ比例し、本発明者らは、そのような形状により、コマ収差を低減できることを見出した。また、補正素子２２ｂ、２２ｃの厚さＬ２は、素子２２ａの厚さＬ１より薄く、すなわち焦点距離が長くなるようにしてあり、その結果デフォーカスを低減することができた。すなわち、斜入射収差低減光学素子２４ｂと２４ｃは、凸レンズ機能を有した上で、斜入射収差のうちのコマ収差とデフォーカスを低減することが可能である。   The oblique incident aberration reducing optical elements 22b and 22c other than the central portion in the array form a convex lens shape in which the uniform film thickness lines 26b and 26c on the uniform film surface form a circle, and the center position of the circle is the uniform film thickness. As the surface height increases, the structure gradually moves in the direction of the center of the oblique incident aberration reducing optical element 24a (the origin of the coordinate system ZXa) depending on the angle of oblique incidence on the objective lens 6. The shift amount of the center position from the origin of the coordinate systems ZXb and ZXc is proportional to the product of the height of the uniform film thickness and tan θb, and the product of the height of the uniform film thickness and tan θc, respectively. It has been found that coma can be reduced by a simple shape. Further, the thickness L2 of the correction elements 22b and 22c is thinner than the thickness L1 of the element 22a, that is, the focal length is increased, and as a result, defocusing can be reduced. That is, the oblique incident aberration reducing optical elements 24b and 24c have a convex lens function, and can reduce coma and defocus of the oblique incident aberration.

斜入射収差低減光学素子２４ａ〜２４ｃは、封止基板２５として、例えば厚さ０.５ｍｍのガラス基板１上に、例えば、それぞれの口径が１００μｍ、膜厚がＬ１＝２．５０μｍ、Ｌ２＝２．４８μｍとして形成している。素子２４ａのレンズ機能の開口数は、例えば０．０５、素子２４ｂ、２４ｃのレンズ機能の開口数は、例えば、０．０４９８である。θｂ＝θｃ＝０．３２°に対応した光学素子２４ｂ、２４ｃにおいて、膜厚０のときの最外周円（有効径を与える円）のＺＸｂ、ＺＸｃの原点からの中心位置の最大シフト量はそれぞれ、−０．７μｍ、０．７μｍであった。このような光学素子２４は、公知の電子ビーム描画用により、基板上に塗布した感光レジスト上に、所定の形状になるように電子ビームを照射して現像処理を行い、素子形状を作製して、これを原盤として、例えば、ニッケル電鋳法で金型を作製し、例えば、ＵＶ硬化樹脂や射出成形用樹脂を用いて金型から複製することのより原盤と同一の光学素子が低価格で作製可能である。特に、本発明の素子が、光源２０の発振部２３の数だけアレイ状に配列しているときは、この方法を用いると、一度に同じ特性で、精度よく形成できるため効果は大きい。   The oblique incidence aberration reducing optical elements 24a to 24c are, for example, on a glass substrate 1 having a thickness of 0.5 mm as a sealing substrate 25, for example, each having a diameter of 100 μm, a film thickness of L1 = 2.50 μm, and L2 = 2. .48 μm. The numerical aperture of the lens function of the element 24a is, for example, 0.05, and the numerical aperture of the lens function of the elements 24b, 24c is, for example, 0.0498. In the optical elements 24b and 24c corresponding to θb = θc = 0.32 °, the maximum shift amounts of the center positions from the origin of ZXb and ZXc of the outermost circumference circle (circle giving an effective diameter) when the film thickness is 0 are respectively , −0.7 μm and 0.7 μm. Such an optical element 24 is formed by irradiating an electron beam to a predetermined shape on a photosensitive resist coated on a substrate by a known electron beam drawing to develop a device shape. Using this as a master, for example, a mold is produced by a nickel electroforming method, and for example, the same optical element as the master is manufactured at a low price by copying from a mold using a UV curable resin or an injection molding resin. It can be produced. In particular, when the elements of the present invention are arranged in an array as many as the oscillating portions 23 of the light source 20, the use of this method has a great effect because the same characteristics can be formed at a time with high accuracy.

次に、所望の記録層１ｃから別の記録層に記録層を変えて記録する場合について説明する。この場合、記録するまでに収束光７が通過する記録部３の厚さが記録層（記録深さ）ごとに異なるので、光源２０から対物レンズ６までの光路中に設けた球面収差補正素子１３で記録部３中に記録する記録ピット５の記録深さに応じて、上記球面収差補正素子１３は球面収差量を制御しながら記録するようにし、良好な記録ピット５を形成した。球面収差補正素子１３は、対物レンズ６に入射する出射光８を平行光から発散光もしくは収束光に変えることにより、または球面収差の逆の位相分布を与えることにより、球面収差（主に３次球面収差）を補正することが可能で、例えば、液晶光学素子、拡大率可変ビームエキスパンダーや、可動コリメータレンズを用いることができる。液晶光学素子の場合、液晶に電圧を印加することでその屈折率分布を制御してレンズ作用を持たせるか、あるいは球面収差を打ち消す位相分布になるようにすれば球面収差補正が可能である。拡大率可変ビームエキスパンダーでは凹レンズと凸レンズを組み合わせてアクチュエータ等で両レンズの光軸方向の間隔を可変にして拡大率を変化させることにより球面収差補正が可能であり、また、可動コリメータレンズでは光源とコリメータレンズの間隔をアクチュエータ等で変えることにより球面収差補正が可能となる。   Next, a case where recording is performed by changing the recording layer from the desired recording layer 1c to another recording layer will be described. In this case, since the thickness of the recording unit 3 through which the convergent light 7 passes before recording differs for each recording layer (recording depth), the spherical aberration correction element 13 provided in the optical path from the light source 20 to the objective lens 6. Thus, according to the recording depth of the recording pit 5 recorded in the recording unit 3, the spherical aberration correction element 13 performs recording while controlling the amount of spherical aberration, and the good recording pit 5 is formed. The spherical aberration correction element 13 changes the outgoing light 8 incident on the objective lens 6 from parallel light to divergent light or convergent light, or gives a phase distribution opposite to the spherical aberration, thereby providing spherical aberration (mainly third-order aberration). For example, a liquid crystal optical element, a magnification variable beam expander, or a movable collimator lens can be used. In the case of a liquid crystal optical element, spherical aberration can be corrected by applying a voltage to the liquid crystal to control its refractive index distribution so as to have a lens action, or to obtain a phase distribution that cancels spherical aberration. In the variable magnification expander, the spherical aberration can be corrected by combining the concave and convex lenses and changing the magnification in the optical axis direction of both lenses with an actuator, etc., and changing the magnification. The spherical aberration can be corrected by changing the interval between the collimator lenses by an actuator or the like.

本発明者らは、斜入射収差補正素子が無い場合、球面収差補正素子１３の補正量を変化させて、情報記録媒体２１の記録部３に３次元的に記録または再生を行う場合、球面収差補正を行うことにより、対物レンズ６に斜入射になるビームの集光スポット性能が著しく劣化する（特に斜入射によるコマ収差が増大）傾向があることを見出した。   In the case where there is no oblique incidence aberration correction element, the present inventors change the correction amount of the spherical aberration correction element 13 to perform three-dimensional recording or reproduction on the recording unit 3 of the information recording medium 21. It has been found that by performing the correction, the converging spot performance of the beam that is obliquely incident on the objective lens 6 tends to be remarkably deteriorated (in particular, coma aberration due to oblique incidence increases).

例えば、所望の記録層１ｃに記録した後に、例えば、２０μｍ奥の別の記録層１ｅに記録する場合、球面収差を補正するが、斜入射収差補正素子２４ｂ、２４ｃが無い場合、前述したように、記録層１ｃでは収束光７ｂと７ｃは焦点でトータルの斜入射収差は１５ｍλだったが、記録層１ｅでは、（３次の）球面収差を補正した場合、トータルの波面収差は高次（５次以上）の球面収差を含んで３１ｍλに増加した。その内訳は、コマ収差２４ｍλ、非点収差４ｍλ、デフォーカス９ｍλであった。すなわち、非点収差とデフォーカスは変わらなかったが、コマ収差が１０ｍλから２４ｍλと大幅に増大することが分かった。従って、斜入射収差補正素子２４ｂ、２４ｃを設けて、特にコマ収差は低減して用いることにより、球面収差補正素子を設けて球面収差を補正しながら、３次元的に記録再生しても、斜入射収差の劣化を抑えられるため、特に本発明の効果は大きい。   For example, after recording on the desired recording layer 1c, for example, when recording on another recording layer 1e at a depth of 20 μm, the spherical aberration is corrected, but when the oblique incident aberration correction elements 24b and 24c are not provided, as described above. In the recording layer 1c, the convergent lights 7b and 7c are the focal points and the total oblique incident aberration is 15 mλ. However, in the recording layer 1e, when the (third order) spherical aberration is corrected, the total wavefront aberration is higher (5 (Including the second or higher) spherical aberration, and increased to 31 mλ. The breakdown was coma aberration 24 mλ, astigmatism 4 mλ, and defocus 9 mλ. That is, astigmatism and defocus did not change, but it was found that the coma increased significantly from 10 mλ to 24 mλ. Accordingly, the oblique incidence aberration correction elements 24b and 24c are provided, and particularly the coma aberration is reduced, so that even if three-dimensional recording / reproduction is performed while the spherical aberration correction element is provided to correct the spherical aberration, Since the deterioration of the incident aberration can be suppressed, the effect of the present invention is particularly great.

（実施の形態２）
次に、本発明の実施の形態２の光学情報記録再生装置について、図４を用いて、上記実施の形態１と異なる点を中心に説明する。 (Embodiment 2)
Next, the optical information recording / reproducing apparatus according to the second embodiment of the present invention will be described with reference to FIG. 4 focusing on differences from the first embodiment.

図４（ａ）は本発明の実施の形態２の光学情報記録再生装置における斜入射収差低減光学素子の構造を示す側面図、図４（ｂ）は本発明の実施の形態２の光学情報記録再生装置における斜入射収差低減光学素子の構造を示す底面図、図４（ｃ）は本発明の実施の形態２の光学情報記録再生装置における斜入射収差低減光学素子の構造を示す底面図においての等膜厚線を示す図である。   FIG. 4A is a side view showing the structure of the oblique incidence aberration reducing optical element in the optical information recording / reproducing apparatus according to Embodiment 2 of the present invention, and FIG. 4B is the optical information recording of Embodiment 2 of the present invention. FIG. 4C is a bottom view showing the structure of the oblique incidence aberration reducing optical element in the optical information recording / reproducing apparatus according to Embodiment 2 of the present invention. It is a figure which shows an equal film thickness line.

実施の形態１の光学情報記録再生装置と異なる点は、光源の発振部の数が５つに増加している（図示無し）ことと、斜入射収差低減光学素子２４’は、上記発振部の数と同じ数だけ、封止基板２５の裏面にアレイ化して設けた構成（２４’ａ〜２４’ｅ）である。光源の発振部の数が増えることにより、並列記録及び並列再生できる記録ピットの数がその分増えることになり、より高速記録、再生が可能となる。それに対応して光検出器の数も２つ増加させ６つ必要（実施の形態１では４つ）になる。   The difference from the optical information recording / reproducing apparatus of the first embodiment is that the number of oscillating portions of the light source is increased to five (not shown), and the oblique incidence aberration reducing optical element 24 ′ is It is the structure (24'a-24'e) provided in the back surface of the sealing substrate 25 by the same number as the number. Increasing the number of oscillators of the light source increases the number of recording pits that can be recorded and reproduced in parallel, thereby enabling higher speed recording and reproduction. Correspondingly, the number of photodetectors is increased by two to require six (four in the first embodiment).

斜入射収差低減光学素子２４’は、中央部２４’ａ、その周囲部２４’ｂ、２４’ｃの形状は、実施の形態１の光学情報記録再生装置の斜入射収差低減光学素子２４ａ、２４ｂ、２４ｃとそれぞれ同じ構造であり、凸レンズ機能も有している。素子２４’ｂ、２４’ｃは斜入射によるコマ収差とデフォーカスを低減する。さらなる斜入射（例えば、入射角が０．６４°）となる両端の出射光に対応する２４’ｄと２４’ｅは、凸レンズ機能を有した上で、斜入射収差のうちでコマ収差、デフォーカスを補正する形状に加えて、非点収差まで補正する形状を有している。ただし、斜入射収差低減光学素子２４’ｂ、２４’ｃに比べて、斜入射収差低減光学素子２４’ｄと２４’ｅの凸レンズの焦点距離は、像面湾曲によるデフォーカスを補正するために、さらにその分だけ長くしてある（膜厚を薄くして曲率半径を大きくしてある）。   The oblique incident aberration reducing optical element 24 ′ has a central portion 24′a and peripheral shapes 24′b and 24′c so that the oblique incident aberration reducing optical elements 24a and 24b of the optical information recording / reproducing apparatus of the first embodiment are used. , 24c, and has the same function as a convex lens. Elements 24'b and 24'c reduce coma and defocus due to oblique incidence. 24′d and 24′e corresponding to the emitted light at both ends with further oblique incidence (for example, an incident angle of 0.64 °) have a convex lens function, and coma aberration and demagnetization among the oblique incidence aberrations. In addition to the shape for correcting focus, it has a shape for correcting astigmatism. However, the focal lengths of the convex lenses of the oblique incidence aberration reducing optical elements 24′d and 24′e are less than the oblique incidence aberration reducing optical elements 24′b and 24′c in order to correct defocus due to field curvature. Further, the length is further increased (the film thickness is reduced and the radius of curvature is increased).

素子２４’ｄと２４’ｅは、−Ｙ軸上での高さが一定の等膜厚面上での等膜厚線２６’がＺ軸方向（複数の発振部の配置方向）に長軸をもつ楕円となる凸レンズ形状であり、その楕円形状の中心位置は上記等膜厚面が高くなる（−Ｙ方向）に従い、対物レンズへの斜め入射の角度に依存して、上記中央部の斜入射収差低減光学素子２４’ａのセンター（座標系ＺＸａの原点）方向に徐々に移動する形状である。座標系ＺＸｂ、ＺＸｃの原点からの中心位置のシフト量は、対物レンズ６への斜入射角をそれぞれθｄ、θｅとして、等膜厚面の高さとｔａｎθｄの積、等膜厚面の高さとｔａｎθｅの積にそれぞれ比例し、本発明者らは、そのような形状により、コマ収差を低減できることを見出した。また、等膜厚線２６’Ｚ軸方向（複数の発振部の配置方向）に長軸をもつ楕円となることにより、非点収差が補正できることを見出した。また、楕円の離心率を大きくすることにより大きな非点収差も低減できる。   In the elements 24′d and 24′e, the uniform film thickness line 26 ′ on the uniform film surface having a constant height on the −Y axis has a long axis in the Z-axis direction (arrangement direction of the plurality of oscillation units). The center position of the ellipse shape increases as the surface of the same film thickness increases (−Y direction) and depends on the angle of oblique incidence on the objective lens. This is a shape that gradually moves in the direction of the center of the incident aberration reducing optical element 24′a (the origin of the coordinate system ZXa). The shift amount of the center position from the origin of the coordinate systems ZXb and ZXc is the product of the height of the uniform film thickness and tan θd, and the height of the uniform film thickness and tan θe, where the oblique incident angles to the objective lens 6 are θd and θe, respectively. The present inventors have found that coma can be reduced by such a shape. Further, it has been found that astigmatism can be corrected by forming an ellipse having a major axis in the direction of the equal film thickness line 26 ′ Z-axis (arrangement direction of a plurality of oscillation parts). Also, large astigmatism can be reduced by increasing the eccentricity of the ellipse.

斜入射収差低減光学素子２４’は、封止基板２５として、例えば厚さ０.５ｍｍのガラス基板１上に、例えば、それぞれのＺ軸方向の口径が１００μｍ、膜厚がＬ１＝２．５０μｍ、Ｌ２＝２．４８μｍ、Ｌ３＝２．４４μｍとして形成している。素子２４ａのレンズ機能の開口数は、例えば０．０５、素子２４ｂ、２４ｃのレンズ機能の開口数は、例えば、０．０４９８である。素子２４ｄ、２４ｅのレンズ機能の開口数は、例えば、０．０４９０で、楕円の長軸に対する短軸の比は０．９８である。θｄ＝θｅ＝０．６４°に対応した光学素子２４ｄ、２４ｅにおいて、膜厚０のときの最外周円のＺＸｂ、ＺＸｃの原点からの中心位置の最大シフト量はそれぞれ、−１．４μｍ、１．４μｍであった。   The oblique incidence aberration reducing optical element 24 ′ is, for example, on a glass substrate 1 having a thickness of 0.5 mm as the sealing substrate 25. For example, the diameter in the Z-axis direction is 100 μm, the film thickness is L1 = 2.50 μm, L2 = 2.48 μm and L3 = 2.44 μm. The numerical aperture of the lens function of the element 24a is, for example, 0.05, and the numerical aperture of the lens function of the elements 24b, 24c is, for example, 0.0498. The numerical aperture of the lens function of the elements 24d and 24e is, for example, 0.0490, and the ratio of the minor axis to the major axis of the ellipse is 0.98. In the optical elements 24d and 24e corresponding to θd = θe = 0.64 °, the maximum shift amount of the center position from the origin of ZXb and ZXc of the outermost circumference circle when the film thickness is 0 is −1.4 μm, 1 .4 μm.

斜入射角が大きい場合はその出射光には、前述したように非点収差が大きくなるので、その場合は本形態の斜入射収差低減光学素子２４’を用いて、コマ収差と非点収差を同時に補正するか、それに加えてデフォーカスも補正すると効果的であった。   When the oblique incidence angle is large, the astigmatism of the outgoing light becomes large as described above. In this case, coma and astigmatism are reduced by using the oblique incidence aberration reducing optical element 24 ′ of this embodiment. It was effective to correct at the same time or in addition to correct defocus.

次に、別の形態の斜入射収差低減光学素子に説明する。図５（ａ）は本発明の実施の形態２の光学情報記録再生装置における別の形態の斜入射収差低減光学素子の構造を示す側面図、図５（ｂ）は本発明の実施の形態２の光学情報記録再生装置における別の形態の斜入射収差低減光学素子の構造を示す底面図である。点線でそれに入射する楕円形状の出射光輪郭線が表示されている。   Next, another embodiment of the oblique incidence aberration reducing optical element will be described. FIG. 5 (a) is a side view showing the structure of an oblique incidence aberration reducing optical element of another form in the optical information recording / reproducing apparatus of Embodiment 2 of the present invention, and FIG. 5 (b) is Embodiment 2 of the present invention. It is a bottom view which shows the structure of the oblique incidence aberration reduction optical element of another form in the optical information recording / reproducing apparatus. An elliptical outgoing light outline that is incident on the dotted line is displayed.

本形態の斜入射収差低減光学素子２４”は、対物レンズへの斜め入射の角度が大きくなるほど、厚さを薄くした位相板である。中央部の斜入射収差低減光学素子２４”ａはガラス基板そのもののであり、対物レンズへの入射角が大きくなる出射光に対応して周囲に行くに従って、その厚さが薄くなっている。例えば、図５（ａ）に示した薄くなった分の厚さは、ｔｂ＝ｔｃ＝５．１μｍ、ｔｄ＝ｔｅ＝２１μｍであり、それらの値は、斜入射収差のうち像面湾曲によるデフォーカス成分により決められる。デフォーカス成分を補正することにより、斜入射収差の量は、例えば、斜入射角が０．３２°以上で半分以上低減される効果があった。逆に言うと、斜入射収差の量は、コマ収差と非点収差の成分が残るため、実施の形態１と２の光学情報記録再生装置における斜入射収差低減光学素子２４，２４’に比べて光学特性は劣化するが、斜入射収差低減光学素子２４”の構造は基板の厚さを変えるだけでよく簡単化される。   The oblique incidence aberration reducing optical element 24 ″ of this embodiment is a phase plate whose thickness is reduced as the angle of oblique incidence on the objective lens increases. The oblique incidence aberration reducing optical element 24 ″ a at the center is a glass substrate. The thickness of the objective lens decreases as it goes to the periphery in response to outgoing light that increases the angle of incidence on the objective lens. For example, the thinned thicknesses shown in FIG. 5A are tb = tc = 5.1 μm and td = te = 21 μm, and these values are the values due to the curvature of field of the oblique incidence aberration. Determined by the focus component. By correcting the defocus component, there is an effect that the amount of oblique incidence aberration is reduced by more than half when the oblique incidence angle is 0.32 ° or more, for example. In other words, the amount of the oblique incidence aberration remains as coma and astigmatism components, so that the oblique incidence aberration reducing optical elements 24 and 24 ′ in the optical information recording / reproducing apparatuses of Embodiments 1 and 2 are compared. Although the optical characteristics are deteriorated, the structure of the oblique incidence aberration reducing optical element 24 ″ can be simplified simply by changing the thickness of the substrate.

斜入射収差低減光学素子２４”は、封止基板２５に対してエッチングプロセスにより形成したが、このような光学素子２４”は、これを原盤として、例えば、ニッケル電鋳法で金型を作製し、公知の射出成形や２Ｐ法により、金型から複製することのより原盤と同一の光学素子が低価格で作製可能である。   The oblique incident aberration reducing optical element 24 ″ is formed on the sealing substrate 25 by an etching process. Such an optical element 24 ″ is used as a master and a mold is produced by, for example, nickel electroforming. By using a known injection molding or 2P method, the same optical element as the master can be produced at low cost by duplicating it from the mold.

なお、上記実施の形態で用いた対物レンズとコリメータレンズ、検出レンズは便宜上名付けたものであり、一般にいうレンズと同じである。   The objective lens, the collimator lens, and the detection lens used in the above embodiment are named for convenience and are the same as commonly used lenses.

また、上記実施の形態においては、情報記録媒体として光ディスクを例に挙げて説明したが、同様の情報記録再生装置で厚みや記録密度など複数の仕様の異なる媒体を再生することができるように設計されたカード状やドラム状、テープ状の製品に応用することも本発明の範囲に含まれる。   In the above embodiment, an optical disk is described as an example of the information recording medium. However, the information recording / reproducing apparatus is designed to reproduce a plurality of media having different specifications such as thickness and recording density. Application to a card-like, drum-like, or tape-like product is also included in the scope of the present invention.

本発明の光学情報記録再生装置によれば、３次元的に記録可能な大容量情報記録媒体の光学情報記録再生装置に関し、特に、対物レンズに斜め入射になるビームの集光スポット性能の劣化を低減し、これらのマルチビームにより高速並列記録または高速並列再生が可能な情報記録再生装置を提供できる。   The optical information recording / reproducing apparatus according to the present invention relates to an optical information recording / reproducing apparatus for a large-capacity information recording medium that can be recorded three-dimensionally. An information recording / reproducing apparatus capable of performing high-speed parallel recording or high-speed parallel reproduction with these multi-beams can be provided.

本発明の実施の形態１における光学情報記録再生装置の基本構成と光の伝搬の様子を示す側面図1 is a side view showing the basic configuration of an optical information recording / reproducing apparatus according to Embodiment 1 of the present invention and the state of light propagation; 本発明の実施の形態１の光学情報記録再生装置において、対物レンズへ斜入射する複数の出射光を示す説明図Explanatory drawing which shows the some emitted light which injects into an objective lens diagonally in the optical information recording / reproducing apparatus of Embodiment 1 of this invention （ａ）本発明の実施の形態１の光学情報記録再生装置における斜入射収差低減光学素子の構造を示す側面図（ｂ）本発明の実施の形態１の光学情報記録再生装置における斜入射収差低減光学素子の構造を示す底面図（ｃ）本発明の実施の形態１の光学情報記録再生装置における斜入射収差低減光学素子の構造を示す底面図においての等膜厚線を示す図(A) Side view showing the structure of the oblique incidence aberration reducing optical element in the optical information recording / reproducing apparatus of Embodiment 1 of the present invention (b) Oblique incident aberration reduction in the optical information recording / reproducing apparatus of Embodiment 1 of the present invention Bottom view showing structure of optical element (c) Diagram showing uniform film thickness line in bottom view showing structure of oblique incidence aberration reducing optical element in optical information recording / reproducing apparatus of Embodiment 1 of the present invention （ａ）本発明の実施の形態２の光学情報記録再生装置における斜入射収差低減光学素子の構造を示す側面図（ｂ）本発明の実施の形態２の光学情報記録再生装置における斜入射収差低減光学素子の構造を示す底面図（ｃ）本発明の実施の形態２の光学情報記録再生装置における斜入射収差低減光学素子の構造を示す底面図においての等膜厚線を示す図(A) Side view showing the structure of the oblique incidence aberration reducing optical element in the optical information recording / reproducing apparatus of Embodiment 2 of the present invention (b) Oblique incident aberration reduction in the optical information recording / reproducing apparatus of Embodiment 2 of the present invention Bottom view showing the structure of the optical element (c) A diagram showing a uniform film thickness line in the bottom view showing the structure of the oblique incidence aberration reducing optical element in the optical information recording / reproducing apparatus according to Embodiment 2 of the present invention. （ａ）本発明の実施の形態２の光学情報記録再生装置における別の形態の斜入射収差低減光学素子の構造を示す側面図（ｂ）本発明の実施の形態２の光学情報記録再生装置における別の形態の斜入射収差低減光学素子の構造を示す底面図(A) Side view showing the structure of another oblique incidence aberration reducing optical element in the optical information recording / reproducing apparatus of Embodiment 2 of the present invention (b) In the optical information recording / reproducing apparatus of Embodiment 2 of the present invention Bottom view showing the structure of another form of oblique incidence aberration reducing optical element 従来の光学情報記録再生装置の基本構成図Basic configuration diagram of a conventional optical information recording / reproducing apparatus

符号の説明Explanation of symbols

１ 記録層
２ 中間層
３ 記録部
４ 保護層
５ 記録ピット
６ 対物レンズ
７ 収束光
８ 平行光
９ 基板
１０ 像回転プリズム
１１ 検出レンズ
１２ 立ち上げミラー
１３ 球面収差補正素子
１４ ピンホール（アレイ）
１５ フォーカス／トラック誤差信号検出素子
１６ コリメータレンズ
１７ 検出収束光（再生信号）
１７’ 検出収束光（フォーカス／トラック誤差信号用）
１８ ビームスプリッタ
１９ 光検出器（再生信号用）
１９’ 光検出器（フォーカス／トラック誤差信号用）
２０ 光源
２１ 情報記録媒体
２２ 出射光
２３ 発振部
２４ 斜入射収差低減光学素子
２５ 封止基板
２６ 等膜厚線
２７ 出射光輪郭
２８ トラック DESCRIPTION OF SYMBOLS 1 Recording layer 2 Intermediate | middle layer 3 Recording part 4 Protective layer 5 Recording pit 6 Objective lens 7 Focusing light 8 Parallel light 9 Substrate 10 Image rotation prism 11 Detection lens 12 Raising mirror 13 Spherical aberration correction element 14 Pinhole (array)
15 Focus / track error signal detection element 16 Collimator lens 17 Convergent light (reproduced signal)
17 'Detection convergent light (for focus / track error signal)
18 Beam splitter 19 Photo detector (for reproduction signal)
19 'photodetector (for focus / track error signal)
DESCRIPTION OF SYMBOLS 20 Light source 21 Information recording medium 22 Outgoing light 23 Oscillation part 24 Oblique incident aberration reduction optical element 25 Sealing substrate 26 Equivalent film thickness 27 Outgoing light outline 28 Track

Claims (26)

独立に駆動可能な複数の発振部を備えた記録用または再生用の光源と、３次元的に記録可能な記録部を有する情報記録媒体に上記発振部からの複数の出射光をそれぞれ集光する対物レンズと、上記情報記録媒体からの複数の反射光をそれぞれ検出する光検出器とを備え、上記光源と上記対物レンズの光路間に、上記対物レンズへ斜め入射する出射光に対応して、斜め入射により生じる収差を低減する斜入射収差低減光学素子を具備することを特徴とする光学情報記録再生装置。 A plurality of light emitted from the oscillating unit is condensed on an information recording medium having a recording or reproducing light source having a plurality of independently oscillating units and a three-dimensionally recordable unit. An objective lens and a photodetector for detecting a plurality of reflected lights from the information recording medium, respectively, corresponding to outgoing light obliquely incident on the objective lens between the light source and the optical path of the objective lens; An optical information recording / reproducing apparatus comprising an oblique incident aberration reducing optical element for reducing aberration caused by oblique incidence. 斜入射収差低減光学素子は、少なくとも発振部の数より１つ少ない数だけ同一基板上にアレイ化して設けた請求項１に記載の情報記録媒体。 The information recording medium according to claim 1, wherein the oblique incident aberration reducing optical elements are provided in an array on the same substrate by at least one less than the number of oscillation units. 斜入射収差低減光学素子は、斜め入射により生じるコマ収差、非点収差、デフォーカスの３つの収差のうち、波面収差が１０ｍλより大きい収差を低減する請求項１に記載の光学情報記録再生装置。 2. The optical information recording / reproducing apparatus according to claim 1, wherein the oblique incident aberration reducing optical element reduces an aberration having a wavefront aberration larger than 10 mλ among three aberrations of coma, astigmatism, and defocus caused by oblique incidence. 斜入射収差低減光学素子は、斜め入射により生じるコマ収差のみを低減する請求項１に記載の光学情報記録再生装置。 The optical information recording / reproducing apparatus according to claim 1, wherein the oblique incident aberration reducing optical element reduces only coma aberration caused by oblique incidence. 斜入射収差低減光学素子は、斜め入射により生じるコマ収差とデフォーカスを低減する請求項１に記載の光学情報記録再生装置。 The optical information recording / reproducing apparatus according to claim 1, wherein the oblique incident aberration reducing optical element reduces coma aberration and defocus caused by oblique incidence. 斜入射収差低減光学素子は、斜め入射により生じるデフォーカスのみを低減する請求項１に記載の光学情報記録再生装置。 The optical information recording / reproducing apparatus according to claim 1, wherein the oblique incident aberration reducing optical element reduces only defocus caused by oblique incidence. 斜入射収差低減光学素子は、斜め入射により生じる非点収差をさらに低減する請求項４または５に記載の光学情報記録再生装置。 6. The optical information recording / reproducing apparatus according to claim 4, wherein the oblique incident aberration reducing optical element further reduces astigmatism caused by oblique incidence. 斜入射収差低減光学素子は、光源を封止する封止基板の表面または裏面に設ける請求項１に記載の光学情報記録再生装置。 The optical information recording / reproducing apparatus according to claim 1, wherein the oblique incident aberration reducing optical element is provided on a front surface or a back surface of a sealing substrate for sealing the light source. 斜入射収差低減光学素子は、さらに凸レンズ機能を有し、発振部の数と同じ数だけ同一基板上にアレイ化して設けた請求項１に記載の光学情報記録再生装置。 The optical information recording / reproducing apparatus according to claim 1, wherein the oblique incidence aberration reducing optical element further has a convex lens function and is provided in an array on the same substrate as the number of oscillation units. アレイ化した中央部以外の斜入射収差低減光学素子は、等膜厚面上での等膜厚線が円となる凸レンズ形状であり、その円の中心位置は上記等膜厚面が高くなるに従い、対物レンズへの斜め入射の角度に依存して、上記中央部の斜入射収差低減光学素子のセンター方向に徐々にシフトする請求項９に記載の光学情報記録再生装置。 The oblique incidence aberration reducing optical element other than the center portion arranged in an array has a convex lens shape in which a uniform film thickness line on the uniform film surface is a circle, and the center position of the circle is increased as the uniform film surface increases. The optical information recording / reproducing apparatus according to claim 9, wherein the optical information recording / reproducing apparatus gradually shifts in a center direction of the oblique incidence aberration reducing optical element in the central portion depending on an angle of oblique incidence on the objective lens. アレイ化した中央部以外の斜入射収差低減光学素子は、等膜厚面上での等膜厚線が複数の発振部の配置方向に長軸をもつ楕円となる凸レンズ形状であり、その楕円形状の中心位置は上記等膜厚面が高くなるに従い、対物レンズへの斜め入射の角度に依存して、上記中央部の斜入射収差低減光学素子のセンター方向に徐々にシフトする請求項９に記載の光学情報記録再生装置。 The oblique incidence aberration reducing optical element other than the center part arranged in an array is a convex lens shape in which a uniform film thickness line on the uniform film surface becomes an ellipse having a major axis in the arrangement direction of a plurality of oscillation parts. 10. The center position of is gradually shifted in the center direction of the oblique incidence aberration reducing optical element in the central portion depending on the angle of oblique incidence on the objective lens as the surface with the same thickness increases. Optical information recording / reproducing apparatus. 斜入射収差低減光学素子は、対物レンズへの斜め入射の角度が大きくなるほど、凸レンズの焦点距離を大きくする請求項９に記載の光学情報記録再生装置。 10. The optical information recording / reproducing apparatus according to claim 9, wherein the oblique incidence aberration reducing optical element increases the focal length of the convex lens as the angle of oblique incidence on the objective lens increases. 斜入射収差低減光学素子は、対物レンズへの斜め入射の角度が大きくなるほど、厚さを薄くした位相板である請求項６に記載の光学情報記録再生装置。 7. The optical information recording / reproducing apparatus according to claim 6, wherein the oblique incident aberration reducing optical element is a phase plate whose thickness is reduced as the angle of oblique incidence to the objective lens increases. 光源と情報記録媒体の光路間に球面収差補正素子を備え、記録または再生する記録部の深さ位置に応じて上記球面収差補正素子の補正量を変化させて記録または再生を行う請求項１に記載の光学情報記録再生装置。 2. A recording apparatus according to claim 1, wherein a spherical aberration correction element is provided between an optical path of the light source and the information recording medium, and recording or reproduction is performed by changing a correction amount of the spherical aberration correction element in accordance with a depth position of a recording section to be recorded or reproduced. The optical information recording / reproducing apparatus described. 球面収差補正素子は、光源と対物レンズの光路間に設けた可動コリメータレンズであって、上記光源とコリメータレンズの間隔を変えることにより球面収差を補正する請求項１４に記載の光学情報記録再生装置。 15. The optical information recording / reproducing apparatus according to claim 14, wherein the spherical aberration correction element is a movable collimator lens provided between the light path of the light source and the objective lens, and corrects the spherical aberration by changing the distance between the light source and the collimator lens. . 球面収差補正素子は、光源と対物レンズの光路間に設けた液晶光学素子であって、液晶に電圧分布を印加することでその屈折率分布を変えることにより球面収差を補正する請求項１４に記載の光学情報記録再生装置。 The spherical aberration correction element is a liquid crystal optical element provided between the light path of the light source and the objective lens, and corrects the spherical aberration by changing the refractive index distribution by applying a voltage distribution to the liquid crystal. Optical information recording / reproducing apparatus. 球面収差補正素子は、光源と対物レンズの光路間に設けた拡大率可変ビームエキスパンダーであって、その拡大率を変化させることより球面収差を補正する請求項１４に記載の光学情報記録再生装置。 The optical information recording / reproducing apparatus according to claim 14, wherein the spherical aberration correction element is a variable magnification expansion beam expander provided between the light source and the optical path of the objective lens, and corrects the spherical aberration by changing the magnification ratio. 情報記録媒体から光検出器までの光路中にフォーカス／トラック誤差信号検出素子と、上記フォーカス／トラック誤差信号検出素子と上記光検出器までの光路中に、複数のピンホールを有するピンホールアレイを設け、上記情報記録媒体からの複数の反射光を、上記フォーカス／トラック誤差信号検出素子によりそれぞれ少なくとも２分岐して再生信号とフォーカス／トラック誤差信号とし、上記再生信号は上記それぞれのピンホールを通過させてから光検出器に導き、上記フォーカス／トラック誤差信号はピンホールを通過させないで、上記光検出器とは別の光検出器に導く請求項１に記載の光学情報記録再生装置。 A focus / track error signal detection element in the optical path from the information recording medium to the photodetector, and a pinhole array having a plurality of pinholes in the optical path to the focus / track error signal detection element and the photodetector And a plurality of reflected lights from the information recording medium are branched into at least two by the focus / track error signal detection element, respectively, to be a reproduction signal and a focus / track error signal, and the reproduction signal passes through the respective pinholes. 2. The optical information recording / reproducing apparatus according to claim 1, wherein the optical information recording / reproducing apparatus is guided to a photodetector, and the focus / track error signal is guided to a photodetector different from the photodetector without passing through a pinhole. フォーカス／トラック誤差信号検出素子は、回折型の光学素子であり、上記光学素子からの出射光のうち０次回折光を再生信号とし、１次回折光をフォーカス／トラック誤差信号とする請求項１８に記載の光学情報記録再生装置。 19. The focus / track error signal detection element is a diffractive optical element, and out of the light emitted from the optical element, the 0th-order diffracted light is a reproduction signal, and the first-order diffracted light is a focus / track error signal. Optical information recording / reproducing apparatus. 光源は半導体レーザであり、記録時は記録ピットの長さに応じてパルス幅を１ナノ秒から１００ナノ秒の間で変化させて出射する請求項１に記載の光学情報記録再生装置。 2. The optical information recording / reproducing apparatus according to claim 1, wherein the light source is a semiconductor laser, and the recording is performed by changing the pulse width from 1 nanosecond to 100 nanoseconds according to the length of the recording pit. 非線形吸収現象を用いて記録する請求項１に記載の光学情報記録再生装置。 The optical information recording / reproducing apparatus according to claim 1, wherein recording is performed using a nonlinear absorption phenomenon. 非線形現象は、２光子吸収、もしくは多光子吸収である請求項２１に記載の光学情報記録再生装置。 The optical information recording / reproducing apparatus according to claim 21, wherein the nonlinear phenomenon is two-photon absorption or multi-photon absorption. 光源は、記録用と再生用を兼ねる請求項１に記載の光学情報記録再生装置。 The optical information recording / reproducing apparatus according to claim 1, wherein the light source serves for both recording and reproduction. 光源の複数の発振部は、同一基板上に形成された請求項１に記載の光学情報記録再生装置。 The optical information recording / reproducing apparatus according to claim 1, wherein the plurality of oscillation units of the light source are formed on the same substrate. 光源の複数の発振部は、記録時または再生時に、同時に独立駆動し、複数の情報を同時に記録または再生を行う請求項１に記載の光学情報記録再生装置。 The optical information recording / reproducing apparatus according to claim 1, wherein the plurality of oscillating units of the light source are independently driven simultaneously during recording or reproduction, and simultaneously record or reproduce a plurality of information. 光源の発振部の数は３以上の奇数である請求項１に記載の光学情報記録再生装置。 The optical information recording / reproducing apparatus according to claim 1, wherein the number of oscillation units of the light source is an odd number of 3 or more.
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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2011187157A (en) * 2011-05-06 2011-09-22 Sony Corp Device and method for irradiation of laser beam
US8477580B2 (en) 2010-09-13 2013-07-02 Sony Corporation Objective lens, optical pickup, and optical drive device
US8861322B2 (en) 2011-10-07 2014-10-14 Panasonic Corporation Optical pickup and optical read/write apparatus

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11238246A (en) * 1998-02-19 1999-08-31 Kenwood Corp Optical pickup device
JP2002237083A (en) * 2001-02-08 2002-08-23 Pioneer Electronic Corp Optical pickup device
JP2005235342A (en) * 2004-02-23 2005-09-02 Matsushita Electric Ind Co Ltd Optical information recording and reproducing device
JP2006172600A (en) * 2004-12-15 2006-06-29 Hitachi Ltd 3-dimensional information recording and reproducing method

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11238246A (en) * 1998-02-19 1999-08-31 Kenwood Corp Optical pickup device
JP2002237083A (en) * 2001-02-08 2002-08-23 Pioneer Electronic Corp Optical pickup device
JP2005235342A (en) * 2004-02-23 2005-09-02 Matsushita Electric Ind Co Ltd Optical information recording and reproducing device
JP2006172600A (en) * 2004-12-15 2006-06-29 Hitachi Ltd 3-dimensional information recording and reproducing method

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8477580B2 (en) 2010-09-13 2013-07-02 Sony Corporation Objective lens, optical pickup, and optical drive device
JP2011187157A (en) * 2011-05-06 2011-09-22 Sony Corp Device and method for irradiation of laser beam
US8861322B2 (en) 2011-10-07 2014-10-14 Panasonic Corporation Optical pickup and optical read/write apparatus

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