JP2007294067A - Polarization multiplex recording and reproduction system and polymer material allowing polarization multiple recording - Google Patents

Polarization multiplex recording and reproduction system and polymer material allowing polarization multiple recording Download PDF

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JP2007294067A
JP2007294067A JP2006165085A JP2006165085A JP2007294067A JP 2007294067 A JP2007294067 A JP 2007294067A JP 2006165085 A JP2006165085 A JP 2006165085A JP 2006165085 A JP2006165085 A JP 2006165085A JP 2007294067 A JP2007294067 A JP 2007294067A
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recording
polarization
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irradiation
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JP4666379B2 (en
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Koji Ono
浩司 小野
Yoshihiro Kawatsuki
喜弘 川月
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Hyogo Prefectural Government
Nagaoka University of Technology NUC
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Nagaoka University of Technology NUC
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Abstract

<P>PROBLEM TO BE SOLVED: To enhance recording density of an optical recording system by utilizing a current optical disk optical system. <P>SOLUTION: In a polarization multiplex recording and reproduction system wherein multiplex recording of information is performed by irradiating the same place of a recording medium with optical waves having different polarization states a plurality of times to enhance recording density, the recording medium comprising a polymer material allowing polarization multiple recording, a light controlling the polarization states when information is recorded and a means analyzing polarization states of reproducing light to reproduce information are combined. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

本発明は、光照射によって情報を記録し、光によって記録された情報を読み出す、光情報記録・再生システムにおいて、記録材料として、偏光によって分子配向を制御できる高分子材料を用いた偏光多重記録可能な材料及びシステムに関するものである。   In the optical information recording / reproducing system, in which information is recorded by light irradiation and information recorded by light is read, polarization multiplex recording is possible using a polymer material capable of controlling molecular orientation by polarization as a recording material. Materials and systems.

情報処理技術の進展に伴い、取り扱う情報の量が飛躍的に増大している。光記録分野においては、高密度化への検討が進められている。現在の光記録（ディスク）分野では、プラスチック円盤上に形成された記録媒体にレーザー光を集光し、光吸収に伴う発熱現象を利用して、磁化の反転（光磁気方式）や結晶構造の変換（相変化方式）を行うものである。   With the progress of information processing technology, the amount of information handled has increased dramatically. In the field of optical recording, investigations for higher density are underway. In the current optical recording (disc) field, the laser beam is focused on a recording medium formed on a plastic disk, and the reversal of magnetization (magneto-optical method) or crystal structure is utilized by utilizing the heat generation phenomenon associated with light absorption. Conversion (phase change method) is performed.

これらの光記録方式では、レーザー光線をより小さい領域に絞り込んだ方が、高い記録密度を得ることができるため、なるべく短い波長のレーザー光線を使用する方法で、ＣＤ、ＤＶＤ、次世代ＤＶＤへの高密度化が達成されてきている。   In these optical recording systems, a higher recording density can be obtained by narrowing the laser beam to a smaller area. Therefore, a high-density CD, DVD, and next-generation DVD can be obtained by using a laser beam having a shorter wavelength as much as possible. Has been achieved.

しかしながら、現在提案されている次世代ＤＶＤで使用されているレーザー光源の波長は約405nmであり、これ以上短波長化することは、他の光学部品等の制約から困難が予想され、別のアプローチが必要である。   However, the wavelength of the laser light source used in the next-generation DVD that is currently proposed is about 405 nm, and it is expected that shortening the wavelength beyond this will be difficult due to limitations of other optical components. is required.

高密度記録が可能な次世代光記録方式として、ホログラフィを用いる方法が提案されている。ホログラフィ記録方式では、１と０のデジタル情報を光空間変調素子によってページ情報にしたものを光干渉によって記録する。   As a next-generation optical recording method capable of high-density recording, a method using holography has been proposed. In the holographic recording method, digital information of 1 and 0 is converted into page information by an optical spatial modulation element and recorded by optical interference.

従来の光ディスクと異なり、ページ記録・再生が可能であるため、高密度であるだけでなく、高速な記録・再生が可能である。   Unlike conventional optical disks, page recording / reproduction is possible, so that not only high density but also high-speed recording / reproduction is possible.

しかしながら、干渉露光系などの複雑な光学系が必要とされる。   However, a complicated optical system such as an interference exposure system is required.

また、別のアプローチとして、複数の記録媒体を層状に配し、厚さ方向に多重化し、記録容量を上げる方法が提案されている。   As another approach, a method has been proposed in which a plurality of recording media are arranged in layers and multiplexed in the thickness direction to increase the recording capacity.

記録は、２光子吸収（用いる波長の半分の波長域の吸収を引き起こす非線形光学効果）を用い、厚さ方向に絞られた位置で選択的に記録を行う。複雑な層構造の光記録層が必要であり、光源や光学系も複雑となるという欠点がある。   Recording is performed selectively using a two-photon absorption (non-linear optical effect that causes absorption in a half wavelength region to be used) at a position narrowed in the thickness direction. An optical recording layer having a complicated layer structure is required, and the light source and the optical system are complicated.

さらに別の方法として、感光波長の異なる色素を多層ないしは複合し、多波長の光源を用いて記録する方法も提案されているが、光源が複数必要なことと、読み出しも多波長に対して対応する必要があり、装置が煩雑になる欠点がある。   As another method, a method has been proposed in which dyes having different photosensitive wavelengths are multilayered or combined and recording is performed using a multi-wavelength light source. However, multiple light sources are required, and reading is also supported for multiple wavelengths. There is a disadvantage that the apparatus becomes complicated.

特願２００５−３１７３５２号Japanese Patent Application No. 2005-317352

記録・再生に用いる波長を短くし、狭い領域に光波を絞り込み高密度化を図る方向は限界に来ている。また、ホログラフィを用いる方法や多層膜を用いる方法では、現在の光ディスク光学系の延長で高密度化を図ることが困難である。   The direction of increasing the density by narrowing the wavelength used for recording / reproducing and narrowing the light wave in a narrow area has reached the limit. In addition, it is difficult to increase the density by extending the current optical disk optical system in the method using holography or the method using a multilayer film.

本発明は、以上のような現状に鑑み、できるだけ現在の光ディスク光学システムの延長上で、記録密度を向上させることが可能な偏光多重記録再生システム及び偏光多重記録可能な高分子材料を提供するものである。   In view of the above situation, the present invention provides a polarization multiplexed recording / reproducing system capable of improving the recording density and a polymer material capable of polarization multiplexed recording on the extension of the current optical disc optical system as much as possible. It is.

添付図面を参照して本発明の要旨を説明する。   The gist of the present invention will be described with reference to the accompanying drawings.

偏光照射によって分子配向が制御される機能を有する高分子材料と、この高分子材料の同一箇所に異なる偏光状態の光波を複数回照射する手段と、前記高分子材料の分子配向によって形成された光学的異方性を検出する手段とを有することを特徴とする偏光多重記録再生システムに係るものである。   Polymer material having a function of controlling molecular orientation by irradiation of polarized light, means for irradiating light waves having different polarization states to the same portion of the polymer material a plurality of times, and optics formed by molecular orientation of the polymer material The present invention relates to a polarization multiplexed recording / reproducing system, characterized in that it has means for detecting anisotropy.

また、前記光波を複数回照射する手段として、最初に初期化のための光波照射を行い、次に一回目の照射光とは異なる偏光状態の光波を強度を変調させて照射する手段を用いたことを特徴とする請求項１記載の偏光多重記録再生システムに係るものである。   Further, as means for irradiating the light wave a plurality of times, first, light wave irradiation for initialization is performed, and then a light wave having a polarization state different from that of the first irradiation light is modulated and irradiated. The polarization multiplexed recording / reproducing system according to claim 1.

また、前記分子配向によって形成された光学的異方性を検出する手段として、前記高分子材料にして前記光波が照射されることで情報が記録される記録部を少なくとも一度は透過した光波を、光学的異方性を有する回折素子によって回折させ、この回折光強度を検出することによって、前記記録部を透過した光波の偏光状態を決定する手段を用いたことを特徴とする請求項１，２のいずれか１項に記載の偏光多重記録再生システムに係るものである。   Further, as a means for detecting optical anisotropy formed by the molecular orientation, a light wave transmitted at least once through a recording portion on which information is recorded by being irradiated with the light wave on the polymer material, 2. A means for determining a polarization state of a light wave transmitted through the recording unit by diffracting by a diffraction element having optical anisotropy and detecting the intensity of the diffracted light. The polarization multiplex recording / reproducing system according to any one of the above.

また、直線偏光によって軸ないしは方向選択的に光反応し、偏光軸をかえた複数回の光波の照射によってその都度光反応した部位の配向状態を乱すことなく複数回の軸ないし方向選択的に光反応し得る高分子材料を用いたことを特徴とする請求項１〜３のいずれか１項に記載の偏光多重記録再生システムに係るものである。   In addition, light is selectively reacted in an axis or direction by linearly polarized light, and light is selectively transmitted in a plurality of axes or directions without disturbing the orientation state of the light-reacted portion each time by irradiation with a plurality of light waves with different polarization axes. 4. The polarization multiplexed recording / reproducing system according to claim 1, wherein a polymer material capable of reacting is used.

また、前記光波の照射時、ないしは照射後に分子再配向する高分子材料を用いたことを特徴とする請求項１〜４のいずれか１項に記載の偏光多重記録再生システムに係るものである。   5. The polarization multiplexed recording / reproducing system according to claim 1, wherein a polymer material that undergoes molecular reorientation at the time of irradiation of the light wave or after irradiation is used.

また、前記高分子材料は、少なくとも下式（１）の化学構造を有する成分を含むものであることを特徴とする請求項１〜５のいずれか１項に記載の偏光多重記録再生システムに係るものである。
但し、
ｎ：１〜１２
ｍ：０〜１２
Ｘ：ｎｏｎｅ，−ＣＯＯ−，−ＯＣＯ−，−Ｎ＝Ｎ−，−Ｃ＝Ｃ−または−Ｃ６Ｈ４−
Ｗ：シンナモイル基またはその誘導体などの感光性基 6. The polarization multiplexed recording / reproducing system according to claim 1, wherein the polymer material includes at least a component having a chemical structure represented by the following formula (1). is there.
However,
n: 1-12
m: 0 to 12
X: none, -COO -, - OCO -, - N = N -, - C = C- or -C 6 H 4 -
W: Photosensitive group such as a cinnamoyl group or a derivative thereof

また、直線偏光によって軸ないしは方向選択的に光反応し、偏光軸をかえた複数回の光波の照射によってその都度光反応した部位の配向状態を乱すことなく複数回の軸ないし方向選択的に光反応し得ることを特徴とする偏光多重記録可能な高分子材料に係るものである。   In addition, light is selectively reacted in an axis or direction by linearly polarized light, and light is selectively transmitted in a plurality of axes or directions without disturbing the orientation state of the light-reacted portion each time by irradiation with a plurality of light waves with different polarization axes. The present invention relates to a polymer material capable of polarization multiple recording, which is capable of reacting.

また、前記光波の照射時、ないしは照射後に分子再配向することを特徴とする請求項７記載の偏光多重記録可能な高分子材料に係るものである。   8. The polarization multiplex recordable polymer material according to claim 7, wherein molecular reorientation is performed during or after irradiation with the light wave.

また、少なくとも下式（１）の化学構造を有する成分を含むことを特徴とする請求項７，８のいずれか１項に記載の偏光多重記録可能な高分子材料に係るものである。
但し、
ｎ：１〜１２
ｍ：０〜１２
Ｘ：ｎｏｎｅ，−ＣＯＯ−，−ＯＣＯ−，−Ｎ＝Ｎ−，−Ｃ＝Ｃ−または−Ｃ６Ｈ４−
Ｗ：シンナモイル基またはその誘導体などの感光性基 9. The polymer material according to claim 7, comprising at least a component having a chemical structure represented by the following formula (1):
However,
n: 1-12
m: 0 to 12
X: none, -COO -, - OCO -, - N = N -, - C = C- or -C 6 H 4 -
W: Photosensitive group such as a cinnamoyl group or a derivative thereof

本発明は上述のように構成したから、本発明では、光記録密度を向上させるために、記録部の同一箇所に異なる偏光状態の光波を複数回照射し、その照射履歴に応じた光学異方性が誘起される高分子材料及び、それを用いた偏光多重記録再生システムが提供される。   Since the present invention is configured as described above, in the present invention, in order to improve the optical recording density, the same location of the recording unit is irradiated with a plurality of light waves having different polarization states, and an optical anisotropic according to the irradiation history. There are provided a polymeric material in which the property is induced and a polarization multiplexed recording / reproducing system using the same.

本発明では、請求項１に記載したように、記録を行う光源（光波）の偏光状態を制御し、同一箇所に複数回の照射を行う手段と、偏光照射によって分子配向が制御される機能を有する高分子材料と、分子配向によって形成された光学異方性を検出する手段、を有することで、偏光多重記録再生システムが提供される。例えば直線偏光を用いて記録を行う場合、その偏光方位角を回転させて、おのおのの偏光方位角に応じて異なる情報を重ねがきできれば、記録密度が向上する。本発明では、異なる情報を異なる偏光状態の光波で、偏光照射によって光学的異方性が誘起される高分子材料に記録し、その光学的異方性を検出することによって実現する。   In the present invention, as described in claim 1, the polarization state of the light source (light wave) for recording is controlled, the means for irradiating the same location a plurality of times, and the function for controlling the molecular orientation by the polarization irradiation. A polarization multiplexed recording / reproducing system is provided by having the polymer material having the unit and means for detecting the optical anisotropy formed by the molecular orientation. For example, when recording is performed using linearly polarized light, if the polarization azimuth angle is rotated and different information can be overlaid according to each polarization azimuth angle, the recording density is improved. In the present invention, different information is recorded on a polymer material in which optical anisotropy is induced by polarized light irradiation with light waves having different polarization states, and the optical anisotropy is detected.

さらに、本発明では、請求項２に記載されているように、偏光多重記録方式として、最初に初期化のための光波照射を行い、次に一回目の照射光とは異なる偏光状態の光波を強度を変調させて照射することで、実用性の高い、偏光多重記録システムを形成できる。この記録方式では、例えば最初に直線偏光で前面を露光しておき、次に、直線偏光の偏光方位角を回転させて、強度を変えて記録を行う。記録は、最初の光波の電界ベクトルと次の光波の電界ベクトルの和として記録されるため、強度を変える事によってベクトル総和の方向を変えることができ、偏光多重記録が達成される。この方法によれば、偏光方向を変調して記録する方法に比べて、既存の強度変調方式を使えるため、より実用性が高まる。   Furthermore, in the present invention, as described in claim 2, as a polarization multiplex recording method, light wave irradiation for initialization is first performed, and then a light wave having a polarization state different from the first irradiation light is generated. By irradiating with the intensity modulated, a highly practical polarization multiplexed recording system can be formed. In this recording method, for example, the front surface is first exposed with linearly polarized light, and then recording is performed by changing the intensity by rotating the polarization azimuth angle of the linearly polarized light. Since recording is recorded as the sum of the electric field vector of the first light wave and the electric field vector of the next light wave, the direction of the vector sum can be changed by changing the intensity, and polarization multiplex recording is achieved. According to this method, since the existing intensity modulation method can be used as compared with the method of recording by modulating the polarization direction, the practicality is further increased.

さらに、本発明では、請求項３に記載しているように、記録部に分子配向によって形成された光学異方性を検出する手段として、記録部を少なくとも一度は透過した光を、光学的異方性を有する回折素子によって回折させ、その回折光強度を検出することによって、記録部の透過光の偏光状態を決定する方法を用いることで、偏光多重記録再生システムが提供される。偏光多重記録された結果、記録材料中には、多重の履歴に応じた光学的異方性が誘起される。このような部位を少なくとも一度は透過した光波は、光学的異方性に応じて偏光状態に影響を受けるため、その偏光状態を検出することによって、多重化された情報を再生することが可能である。偏光状態を検出する方法としては、グラントムソンプリズムのような検光子を回転させる方法も考えられるが、高速性から光学的異方性を有する偏光回折格子の回折光から決定する方法が有効であり、例えば、特願２００５−３１７３５２に記載の技術を有効に用いることができる。   Further, in the present invention, as described in claim 3, as a means for detecting optical anisotropy formed in the recording portion by molecular orientation, the light transmitted through the recording portion at least once is optically different. A polarization multiplexed recording / reproducing system is provided by using a method of determining the polarization state of the transmitted light of the recording unit by diffracting by a diffractive element having directionality and detecting the intensity of the diffracted light. As a result of the polarization multiplex recording, optical anisotropy is induced in the recording material in accordance with the multiplex history. A light wave that has passed through such a part at least once is affected by the polarization state according to the optical anisotropy. Therefore, it is possible to reproduce multiplexed information by detecting the polarization state. is there. As a method for detecting the polarization state, a method of rotating an analyzer such as a Glan-Thompson prism is also conceivable, but a method of determining from the diffracted light of a polarization diffraction grating having optical anisotropy is effective for high speed. For example, the technique described in Japanese Patent Application No. 2005-317352 can be used effectively.

さらに本発明では、請求項４，７に記載しているように、直線偏光によって軸ないしは方向選択的に光反応し、偏光軸をかえた複数回の偏光照射によってその都度光反応した部位の配向状態を乱されることなく複数回の軸ないし方向選択的な光反応ができる高分子材料と、それを用いた光多重記録再生システムが提供される。偏光軸を変えた複数回の照射によって配向状態が乱されることなく記録されるため、トータルの配向は、照射された光電界ベクトルの総和として決定される。そのベクトル和で記録された光学的異方性を検出することで、多重に記録された履歴を判別することができる。   Furthermore, in the present invention, as described in claims 4 and 7, the orientation of the site which photoreacts in an axial or direction-selective manner by linearly polarized light and photoreacted each time by a plurality of times of polarized light irradiation with the polarization axis changed. Provided are a polymer material capable of photoreactions that are axially or directionally selected a plurality of times without disturbing the state, and an optical multiplex recording / reproducing system using the same. Since the alignment state is recorded without being disturbed by a plurality of irradiations with different polarization axes, the total alignment is determined as the sum of the irradiated optical electric field vectors. By detecting the optical anisotropy recorded by the vector sum, it is possible to discriminate the history recorded in multiple.

さらに本発明では、請求項５，８に記載しているように、上記高分子材料が照射時、ないしは照射後に分子再配向する偏光多重記録可能な高分子材料及びそれを用いた偏光多重記録再生システムが提供される。   Further, in the present invention, as described in claims 5 and 8, a polymer material capable of polarization multiplex recording in which the polymer material undergoes molecular reorientation upon irradiation or after irradiation, and polarization multiplex recording / reproduction using the same A system is provided.

さらに本発明では、請求項６，９に記載しているように、高分子材料が少なくとも上記式（１）の化学構造を含む材料であることで偏光多重記録再生システム用の高分子材料及びそれを用いた偏光多重記録再生システムが提供される。そのような高分子材料として、Macromolecules，Vol.30，No.21，pp.6680-6682(1997)やMacromolecules，Vol.35，No.3，pp.706-713(2002)に掲載されている材料や、感度を用いるレーザーに対して適正にするためにMacromolecules，Vol.38，No.9，pp.3903-3908(2005)に掲載されている材料を用いることができるがこれらに限定されるものではない。   Further, in the present invention, as described in claims 6 and 9, the polymer material is a material containing at least the chemical structure of the above formula (1), so that the polymer material for the polarization multiple recording / reproducing system and the A polarization multiplexed recording / reproducing system using the above is provided. Such polymer materials are listed in Macromolecules, Vol. 30, No. 21, pp. 6680-6682 (1997) and Macromolecules, Vol. 35, No. 3, pp. 706-713 (2002). Materials and materials listed in Macromolecules, Vol.38, No.9, pp.3903-3908 (2005) can be used in order to make them suitable for lasers using sensitivity, but are not limited to these. It is not a thing.

好適と考える本発明の実施形態（発明をどのように実施するか）を、図面に基づいて本発明の作用を示して簡単に説明する。   Embodiments of the present invention that are considered suitable (how to carry out the invention) will be briefly described with reference to the drawings, illustrating the operation of the present invention.

すでに述べたように、情報技術の進展に伴い、光記録システムの高密度化が必要とされており、従来から行われてきた、短波長化による高密度化が限界に達している。このような状況を打開するために、ホログラフィを応用した技術や記録媒体を多層化する技術が検討されている。これらの技術は、従来の光ディスクを用いた光記録システムの大きな変更が必要であり、実用化の障害となっている。   As described above, with the progress of information technology, it is necessary to increase the density of the optical recording system, and the density increase by shortening the wavelength, which has been conventionally performed, has reached the limit. In order to overcome such a situation, a technique applying holography and a technique of multilayering recording media are being studied. These technologies require major changes in the optical recording system using the conventional optical disc, and are impeding practical use.

現状の光ディスクシステム技術の多くの部分を踏襲した上で、記録密度を向上するために、本発明では光波の偏光に着目した。偏光は、光波の電界ベクトルの描く時間的軌跡で定義されており、一般的には図１に示すような楕円状の軌跡を描く。楕円の形状は、光波電界ベクトルの各成分Ｅｘ、Ｅｙの振幅Ａｘ、Ａｙとその位相差によって決まり、楕円の長軸の長さａと短軸の長さｂ及び楕円の方位角αで特徴付けられる。これらの組合せによって、無限の形状の偏光が存在するため、もし各偏光状態に独立に情報を載せてそれを多重に記録・再生できれば、既存の光ディスクシステムに記録光の偏光の制御系と記録媒体からの読み出し光の偏光読み取り系を付けることによって多重化による高密度化が可能になることになる。 In order to improve the recording density after following many parts of the current optical disk system technology, the present invention focuses on the polarization of light waves. Polarization is defined by a temporal trajectory drawn by an electric field vector of a light wave, and generally draws an elliptical trajectory as shown in FIG. The shape of the ellipse is determined by the amplitudes A x and A y of the components E x and E y of the lightwave electric field vector and the phase difference thereof. The major axis length a, the minor axis length b, and the azimuth angle of the ellipse Characterized by α. Because of these combinations, there is an infinite shape of polarized light. Therefore, if information can be put on each polarization state independently and recorded and reproduced in a multiplexed manner, the polarization control system and recording medium of the recording light can be added to the existing optical disk system. By attaching a polarization reading system for the readout light from the light, it becomes possible to increase the density by multiplexing.

このような偏光記録を可能にするためには、各種偏光に応じて光学特性（具体的には光学的異方性）が変化するような材料の開発が必要である。   In order to enable such polarization recording, it is necessary to develop a material whose optical characteristics (specifically, optical anisotropy) change according to various polarizations.

このようなことが可能な材料として例えば、ネガ型のフォトレジストであるポリビニルシンナメート（PVCi）が知られている。ポリビニルシンナメートフィルムに直線偏光紫外光を照射すると、ケイ皮酸部の-C=C-結合が偏光の電界方向に平行方向となる場合に光を選択的に吸収して２量化し、その部分の屈折率は低下する。このことを利用すれば、光学的異方性を周期的に制御することが可能であるが、誘起される屈折率異方性は0.01以下と非常に小さいため実用性に乏しい。   For example, polyvinyl cinnamate (PVCi), which is a negative photoresist, is known as a material capable of such a purpose. When the polyvinyl cinnamate film is irradiated with linearly polarized ultraviolet light, when the -C = C- bond of the cinnamic acid portion is parallel to the direction of the electric field of polarized light, light is selectively absorbed and dimerized. The refractive index of decreases. By utilizing this fact, it is possible to periodically control the optical anisotropy, but the induced refractive index anisotropy is as small as 0.01 or less, so it is not practical.

また、その他の代表的な材料として、アゾベンゼンを含む高分子材料を用いることが検討されている。アゾベンゼン分子は光や熱のような外部からの刺激によってシス体とトランス体の間で異性化反応が起こり、このことを利用して分子配向を制御することができ周期的な分子配向制御も光照射によって行うことが可能である。しかしながら、従来検討されてきた、アゾベンゼン部位が分子配向を生じさせる主要光反応部位となる高分子材料では、光学的異方性の発現性があまり大きくないだけでなく、熱や光などの外場の影響によって特性が変化するため、高い安定性を要求される光記録材料への応用が困難である。   As other representative materials, use of a polymer material containing azobenzene has been studied. The azobenzene molecule undergoes an isomerization reaction between the cis- and trans-forms by external stimuli such as light and heat, and this can be used to control the molecular orientation, and periodic molecular orientation control is also possible. It can be done by irradiation. However, the polymer materials in which the azobenzene moiety is a main photoreactive site that causes molecular orientation, which has been studied in the past, not only have a large optical anisotropy, but also external fields such as heat and light. Therefore, it is difficult to apply to optical recording materials that require high stability.

上記の状況を鑑み、本発明では、例えば高分子材料が少なくとも上記式（１）の化学構造を含む材料である光反応性高分子液晶を用いることで、メソゲン配向に伴う大きな屈折率異方性による高機能化と高い耐熱性を発現できることを応用し、本発明に係わる光記録材料を提供する。   In view of the above situation, in the present invention, for example, a high refractive index anisotropy associated with mesogen orientation is obtained by using a photoreactive polymer liquid crystal in which the polymer material is a material including at least the chemical structure of the above formula (1). The optical recording material according to the present invention is provided by applying the high functionality and high heat resistance.

光記録の際に照射する光波の偏光を制御する方法としては、本発明においては特に限定するものではないが、液晶素子等の電界制御型位相制御素子を用いることが、高速性や制御性の点から有効である。   The method of controlling the polarization of the light wave irradiated during optical recording is not particularly limited in the present invention, but it is possible to use an electric field control type phase control element such as a liquid crystal element for high speed and controllability. It is effective from the point of view.

偏光多重記録を行う高分子材料としては光学的透明性と充分な分子配向と光学的異方性を発現するものであれば良いが、側鎖ないしは主鎖に少なくとも１種の光反応性のメソゲンを有する高分子液晶を用いることによって、材料の液晶性を利用して、高度に配向した状態を形成でき、大きな光学的異方性を発現することができる。さらに好ましくは、高分子層が側鎖に光架橋性のメソゲンを有する高分子液晶であってそのメソゲン末端に光反応性基を有することによって、架橋構造を取ることによって恒久的な情報記録の際に必要な耐熱性を確保することが可能となる。そのような高分子材料として、Macromolecules，Vol.30，No.21，pp.6680-6682(1997)やMacromolecules，Vol.35，No.3，pp.706-713(2002)に掲載されている材料や、感度を用いるレーザーに対して適正にするためにMacromolecules，Vol.38，No.9，pp.3903-3908(2005)に掲載されている材料を用いることができるがこれらに限定されるものではない。   The polymer material for performing polarization multiple recording is not particularly limited as long as it exhibits optical transparency, sufficient molecular orientation, and optical anisotropy, but at least one photoreactive mesogen in the side chain or main chain. By using a polymer liquid crystal having the above, it is possible to form a highly oriented state by utilizing the liquid crystallinity of the material and to exhibit a large optical anisotropy. More preferably, the polymer layer is a polymer liquid crystal having a photocrosslinkable mesogen in the side chain, and having a photoreactive group at the mesogen end, thereby taking a crosslinked structure for permanent information recording. It is possible to ensure the heat resistance necessary for the operation. Such polymer materials are listed in Macromolecules, Vol. 30, No. 21, pp. 6680-6682 (1997) and Macromolecules, Vol. 35, No. 3, pp. 706-713 (2002). Materials and materials listed in Macromolecules, Vol.38, No.9, pp.3903-3908 (2005) can be used in order to make them suitable for lasers using sensitivity, but are not limited to these. It is not a thing.

さらに、偏光多重記録では、多重記録光の電界ベクトルの総和として記録がなされる。   Further, in polarization multiplex recording, recording is performed as the sum of electric field vectors of multiplex recording light.

このようなシステムにおいては、多重記録を行う際に、偏光軸をかえた複数回の偏光照射によってその都度光反応した部位の配向状態を乱されることなく複数回の軸ないし方向選択的な光反応ができる高分子材料を用いることが、再生系の簡便化の点から好ましい。   In such a system, when performing multiplex recording, a plurality of times of axial or direction-selective light is obtained without disturbing the alignment state of the site that has photoreacted each time by irradiation of polarized light with different polarization axes. It is preferable to use a polymer material capable of reacting from the viewpoint of simplifying the regeneration system.

偏光多重記録に用いられる光記録媒体としては、従来の光ディスク同様、透明基板上にトラッキングのための溝を設けた円盤状の形態のものをそのまま用いることができる。再生は、透過型であっても反射型であっても可能であるが、例えば、高分子記録層の上に反射膜を設けて、反射構造とすることによって、トラッキングやフォーカシングのサーボ機構としてすでに確立されている現状の光ディスクの技術をそのまま用いることができる。   As an optical recording medium used for polarization multiplex recording, a disk-shaped recording medium having a tracking groove on a transparent substrate can be used as it is, as in a conventional optical disk. Reproduction can be either transmissive or reflective. For example, by providing a reflective film on a polymer recording layer to form a reflective structure, it can already be used as a servo mechanism for tracking and focusing. The established current optical disk technology can be used as it is.

また、現在の光磁気ディスクでは、記録膜の保護と記録部のカー効果に伴う信号の増強の目的で、透明誘電体膜と反射膜からなる多層構造を採用しているが、同様の技術を本発明に応用することも有効である。   The current magneto-optical disk employs a multilayer structure consisting of a transparent dielectric film and a reflective film for the purpose of protecting the recording film and enhancing the signal accompanying the Kerr effect of the recording part. Application to the present invention is also effective.

偏光多重記録された情報の読み出しは、記録部位の分子配向によって誘起された光学的異方性を検出することによって行う。光学的異方性を検出するためには、記録媒体からの信号光の偏光情報を偏光素子を通して、強度情報に変換して読み出す方法や、光干渉を用いる方法などが考えられるが、特願２００５−３１７３５２に記載されている異方性を有する回折格子素子を用いる方法が高速性や簡便さの面で優れている。例えば特願２００５−３１７３５２では、液晶分子配向方向を空間的に変調させることによって偏光依存の回折格子を形成し、偏光検出を簡便かつ高速に行う方法が提案されている。また、用いる光の波長程度以下の周期構造を形成した構造異方性を利用した光学素子によって偏光検出を行う方法も有効である。   Reading of information recorded by polarization multiplexing is performed by detecting optical anisotropy induced by the molecular orientation of the recording site. In order to detect the optical anisotropy, a method of reading out polarization information of signal light from a recording medium by converting it into intensity information through a polarizing element, a method of using optical interference, and the like can be considered. The method using the diffraction grating element having anisotropy described in -317352 is excellent in terms of high speed and simplicity. For example, Japanese Patent Application No. 2005-317352 proposes a method of forming polarization-dependent diffraction gratings by spatially modulating the liquid crystal molecule alignment direction and performing polarization detection simply and at high speed. Also effective is a method of detecting polarization using an optical element using structural anisotropy in which a periodic structure having a wavelength of about the wavelength of the light used is formed.

光記録媒体を形成する場合には、本発明による高分子材料をフィルム化する必要がある。高分子材料を溶解する溶媒、濃度および溶解方法は特に限定されず、用いる基板や乾燥時間などによって適宜選択される。溶液を均一に塗布する方法としては、スピンコート法、グラビアコート法、コンマコート法などが考えられるが、特に限定されるものではなく、必要とされる面積、基板形状、精度などによって適宜選択される。基板は透明基板であれば特に限定されるものではないが、機能性高分子層の機能を最大限引き出すために、固有複屈折率の小さい透明基板材料が好ましい。このような性質を有する透明基板材料としては、各種ガラス、石英、などの無機材料、ポリメチルメタクリレート、ポリカーボネート、ノルボルネン系高分子、セルロース系高分子、ポリエステル系高分子、などの有機材料を例示できる。基板の形態は特に限定するものではなく、板状、フィルム状などを目的によって適宜選択できるが、現状の光ディスクシステムとの互換性等を考慮する場合には、円盤状の形状のものを回転させながら書き込みあるいは読み出しをできる構成が好ましい。   In the case of forming an optical recording medium, it is necessary to form a polymer material according to the present invention into a film. The solvent, concentration, and dissolution method for dissolving the polymer material are not particularly limited, and are appropriately selected depending on the substrate used, the drying time, and the like. As a method for uniformly applying the solution, a spin coating method, a gravure coating method, a comma coating method, and the like can be considered, but the method is not particularly limited and is appropriately selected depending on the required area, substrate shape, accuracy, and the like. The The substrate is not particularly limited as long as it is a transparent substrate, but a transparent substrate material having a small intrinsic birefringence is preferable in order to maximize the function of the functional polymer layer. Examples of transparent substrate materials having such properties include inorganic materials such as various types of glass and quartz, and organic materials such as polymethyl methacrylate, polycarbonate, norbornene-based polymers, cellulose-based polymers, and polyester-based polymers. . The form of the substrate is not particularly limited, and a plate shape, a film shape, and the like can be appropriately selected depending on the purpose. However, in consideration of compatibility with the current optical disk system, the disk shape is rotated. However, a configuration capable of writing or reading is preferable.

さらに、本発明で偏光多重記録が可能な材料としては、光波の偏光によって光学的異方性が誘起できる材料系であれば、候補となりえるが、より好ましくは、Macromolecules，Vol.30，No.21，pp.6680-6682(1997)やMacromolecules，Vol.35，No.3，pp.706-713(2002)に掲載されている材料に加え、感度を用いるレーザーに対して適正にするためにMacromolecules，Vol.38，No.9，pp.3903-3908(2005)に掲載されているようなレーザー光に対し光増感作用できうる高分子材料を使うことが最適である。すなわち、一般に架橋性の光反応基は紫外光に対して感度を有するので、405nm光に対しての感度を付与するために、ベンゾフェノンやニトロフェニルなどの増感基を請求項６に示す材料に複合させるか、ないしはそれらを側鎖に有する成分を共重合させることで用いるレーザーに対して最適な感度を付与することができる。   Furthermore, as a material capable of polarization multiplexed recording in the present invention, any material system capable of inducing optical anisotropy by polarization of light waves can be a candidate, but more preferably, Macromolecules, Vol. 30, No. In addition to the materials listed in 21, pp. 6680-6682 (1997) and Macromolecules, Vol. 35, No. 3, pp. 706-713 (2002), in order to make it suitable for lasers using sensitivity It is optimal to use a polymer material capable of photosensitizing the laser beam as described in Macromolecules, Vol.38, No.9, pp.3903-3908 (2005). That is, since a crosslinkable photoreactive group is generally sensitive to ultraviolet light, a sensitizing group such as benzophenone or nitrophenyl is added to the material shown in claim 6 in order to provide sensitivity to 405 nm light. Optimum sensitivity can be imparted to the laser used by combining or by copolymerizing components having them in the side chain.

以下、実施例により本発明をさらに詳細に説明するが、本発明はこれらの例によって限定されるものではない。   EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited by these examples.

本発明の具体的な実施例１について図面に基づいて説明する。   A first embodiment of the present invention will be described with reference to the drawings.

下式（２）
の化学構造式を有する光架橋性高分子液晶をクロロホルムに１重量％の濃度で溶解し、石英基板の上にスピンコーターを用いて約０．３μｍの厚みとなるように塗布した。このフィルムに１５mＷの直線偏光４０５nmの半導体レーザーの光によって記録を行った。直線偏光の偏光方向を０度、１５度、５０度に制御し、それぞれを照射するかしないかによって１，０の情報とし、(1，0，0)，(1，1，0)，(0，1，0)，(1，1，1)，(1，0，1)，(0，1，1)，(0，0，1)の７種類の組合せで重ね書きした。偏光多重記録部位の偏光顕微鏡写真を図２に示す。それぞれのスポットは、偏光子を回転させることで明暗が生じ、識別可能であった。 The following formula (2)
A photocrosslinkable polymer liquid crystal having the following chemical structural formula was dissolved in chloroform at a concentration of 1% by weight and coated on a quartz substrate to a thickness of about 0.3 μm using a spin coater. Recording was performed on this film with light from a semiconductor laser having a linear polarization of 405 nm of 15 mW. The polarization direction of linearly polarized light is controlled to 0 degrees, 15 degrees, and 50 degrees, and the information is 1, 0 depending on whether or not each is irradiated. Overwritten with seven combinations of (0, 1, 0), (1, 1, 1), (1, 0, 1), (0, 1, 1), (0, 0, 1). FIG. 2 shows a polarization micrograph of the polarization multiple recording region. Each spot was bright and dark by rotating the polarizer, and was distinguishable.

実施例１で用いたＰＬＣと同じフィルムに、先ず４０５ｎｍの直線偏光を夫々３５ｍＪ，７０ｍＪ，１４０ｍＪ，２８０ｍＪで照射（Ａ）したフィルムを作製した。続いて、偏光角度を５０℃回転して種々の強度で夫々最初に照射したピットと同位置に４０５ｎｍの直線偏光を照射（Ｂ）した。このフィルムを１８５℃で１分加熱したときの、最初に照射した直線偏光（Ａ）の光強度と２回目に照射した直線偏光（Ｂ）の光強度の比に対する分子配向回転角を図３に示す。この図３から、最初に照射した直線偏光（Ａ）のエネルギー（光強度）に関わらず、分子配向は最初に照射した直線偏光（Ａ）の光強度と２回目に照射した直線偏光（Ｂ）の光強度の比に応じて変化した。このことは、一回目と二回目に照射する偏光の強度比を変えることによりアナログ多重記録が可能なことを示している。   On the same film as the PLC used in Example 1, first, 405 nm linearly polarized light was irradiated (A) at 35 mJ, 70 mJ, 140 mJ, and 280 mJ, respectively. Subsequently, the polarization angle was rotated by 50 ° C., and 405 nm linearly polarized light was irradiated (B) at the same position as the first irradiated pits at various intensities. When this film is heated at 185 ° C. for 1 minute, the rotation angle of the molecular orientation relative to the ratio of the light intensity of the first linearly polarized light (A) and the light intensity of the second linearly polarized light (B) is shown in FIG. Show. From FIG. 3, regardless of the energy (light intensity) of the linearly polarized light (A) irradiated first, the molecular orientation is the light intensity of the linearly polarized light (A) irradiated first and the linearly polarized light (B) irradiated second time. It changed according to the ratio of the light intensity. This indicates that analog multiplex recording is possible by changing the intensity ratio of the polarized light irradiated the first time and the second time.

楕円偏光の電界ベクトルの軌跡である。It is a locus of an elliptically polarized electric field vector. 偏光多重記録を行った記録部の偏光顕微鏡写真である。It is a polarizing microscope photograph of the recording part which performed polarization multiple recording. 光強度比に対する分子配向回転角を示すグラフである。It is a graph which shows the molecular orientation rotation angle with respect to light intensity ratio.

Claims (9)

偏光照射によって分子配向が制御される機能を有する高分子材料と、この高分子材料の同一箇所に異なる偏光状態の光波を複数回照射する手段と、前記高分子材料の分子配向によって形成された光学的異方性を検出する手段とを有することを特徴とする偏光多重記録再生システム。   Polymer material having a function of controlling molecular orientation by irradiation of polarized light, means for irradiating light waves having different polarization states to the same portion of the polymer material a plurality of times, and optics formed by molecular orientation of the polymer material And a polarization multiplexing recording / reproducing system, characterized by comprising: 前記光波を複数回照射する手段として、最初に初期化のための光波照射を行い、次に一回目の照射光とは異なる偏光状態の光波を強度を変調させて照射する手段を用いたことを特徴とする請求項１記載の偏光多重記録再生システム。   As means for irradiating the light wave a plurality of times, first, light wave irradiation for initialization is performed, and then a light wave having a polarization state different from that of the first irradiation light is used after modulating the intensity. The polarization multiplexed recording / reproducing system according to claim 1. 前記分子配向によって形成された光学的異方性を検出する手段として、前記高分子材料にして前記光波が照射されることで情報が記録される記録部を少なくとも一度は透過した光波を、光学的異方性を有する回折素子によって回折させ、この回折光強度を検出することによって、前記記録部を透過した光波の偏光状態を決定する手段を用いたことを特徴とする請求項１，２のいずれか１項に記載の偏光多重記録再生システム。   As a means for detecting the optical anisotropy formed by the molecular orientation, a light wave transmitted at least once through a recording portion on which information is recorded by irradiating the light wave on the polymer material is optically 3. The method according to claim 1, wherein means for determining a polarization state of a light wave transmitted through the recording unit by diffracting by an anisotropic diffraction element and detecting the intensity of the diffracted light is used. The polarization multiplexing recording / reproducing system according to claim 1. 直線偏光によって軸ないしは方向選択的に光反応し、偏光軸をかえた複数回の光波の照射によってその都度光反応した部位の配向状態を乱すことなく複数回の軸ないし方向選択的に光反応し得る高分子材料を用いたことを特徴とする請求項１〜３のいずれか１項に記載の偏光多重記録再生システム。   It reacts photoselectively with axis or direction by linearly polarized light, and reacts photoselectively with multiple axes or directions without disturbing the orientation state of the photoreacted part each time by irradiation of light waves with different polarization axes. The polarization multiplexed recording / reproducing system according to claim 1, wherein the obtained polymer material is used. 前記光波の照射時、ないしは照射後に分子再配向する高分子材料を用いたことを特徴とする請求項１〜４のいずれか１項に記載の偏光多重記録再生システム。   5. The polarization multiplexed recording / reproducing system according to claim 1, wherein a polymer material that reorients molecules during or after the irradiation with the light wave is used. 前記高分子材料は、少なくとも下式（１）の化学構造を有する成分を含むものであることを特徴とする請求項１〜５のいずれか１項に記載の偏光多重記録再生システム。
但し、
ｎ：１〜１２
ｍ：０〜１２
Ｘ：ｎｏｎｅ，−ＣＯＯ−，−ＯＣＯ−，−Ｎ＝Ｎ−，−Ｃ＝Ｃ−または−Ｃ６Ｈ４−
Ｗ：シンナモイル基またはその誘導体などの感光性基 The polarization multiplexed recording / reproducing system according to claim 1, wherein the polymer material includes at least a component having a chemical structure represented by the following formula (1).
However,
n: 1-12
m: 0 to 12
X: none, -COO -, - OCO -, - N = N -, - C = C- or -C 6 H 4 -
W: Photosensitive group such as a cinnamoyl group or a derivative thereof 直線偏光によって軸ないしは方向選択的に光反応し、偏光軸をかえた複数回の光波の照射によってその都度光反応した部位の配向状態を乱すことなく複数回の軸ないし方向選択的に光反応し得ることを特徴とする偏光多重記録可能な高分子材料。   It reacts photoselectively with axis or direction by linearly polarized light, and reacts photoselectively with multiple axes or directions without disturbing the orientation state of the photoreacted part each time by irradiation of light waves with different polarization axes. A polymeric material capable of polarization multiple recording. 前記光波の照射時、ないしは照射後に分子再配向することを特徴とする請求項７記載の偏光多重記録可能な高分子材料。   8. The polymer material capable of polarization multiple recording according to claim 7, wherein molecular reorientation is performed during or after the irradiation of the light wave. 少なくとも下式（１）の化学構造を有する成分を含むことを特徴とする請求項７，８のいずれか１項に記載の偏光多重記録可能な高分子材料。
但し、
ｎ：１〜１２
ｍ：０〜１２
Ｘ：ｎｏｎｅ，−ＣＯＯ−，−ＯＣＯ−，−Ｎ＝Ｎ−，−Ｃ＝Ｃ−または−Ｃ６Ｈ４−
Ｗ：シンナモイル基またはその誘導体などの感光性基
The polymer material capable of polarization multiple recording according to any one of claims 7 and 8, comprising at least a component having a chemical structure represented by the following formula (1).
However,
n: 1-12
m: 0 to 12
X: none, -COO -, - OCO -, - N = N -, - C = C- or -C 6 H 4 -
W: Photosensitive group such as a cinnamoyl group or a derivative thereof
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Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02260127A (en) * 1989-03-30 1990-10-22 Matsushita Electric Ind Co Ltd Polarization multiplex recording method
JPH04113352A (en) * 1990-09-03 1992-04-14 Matsushita Electric Ind Co Ltd Polarization multiple recording medium and production thereof
JPH10300929A (en) * 1997-04-28 1998-11-13 Tdk Corp Polarizing diffraction element, optical pickup, and method for detecting photomagnetic signal
JPH11238251A (en) * 1997-11-10 1999-08-31 Fuji Xerox Co Ltd Optical record medium, optical recording/reproducing method and device
JP2001006208A (en) * 1999-06-23 2001-01-12 Sony Corp Optical recording medium, recording and reproducing method using the same and recording and reproducing device
JP2003013053A (en) * 2001-06-29 2003-01-15 Univ Osaka Photochromic material, photochromic amorphous thin film for information recording, method for information recording and information recording element
JP2005345652A (en) * 2004-06-01 2005-12-15 Fuji Xerox Co Ltd Optical recording material, optical recording medium, and optical recording and reproducing device

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02260127A (en) * 1989-03-30 1990-10-22 Matsushita Electric Ind Co Ltd Polarization multiplex recording method
JPH04113352A (en) * 1990-09-03 1992-04-14 Matsushita Electric Ind Co Ltd Polarization multiple recording medium and production thereof
JPH10300929A (en) * 1997-04-28 1998-11-13 Tdk Corp Polarizing diffraction element, optical pickup, and method for detecting photomagnetic signal
JPH11238251A (en) * 1997-11-10 1999-08-31 Fuji Xerox Co Ltd Optical record medium, optical recording/reproducing method and device
JP2001006208A (en) * 1999-06-23 2001-01-12 Sony Corp Optical recording medium, recording and reproducing method using the same and recording and reproducing device
JP2003013053A (en) * 2001-06-29 2003-01-15 Univ Osaka Photochromic material, photochromic amorphous thin film for information recording, method for information recording and information recording element
JP2005345652A (en) * 2004-06-01 2005-12-15 Fuji Xerox Co Ltd Optical recording material, optical recording medium, and optical recording and reproducing device

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