JP4164308B2

JP4164308B2 - Light amount adjusting element and imaging apparatus using the same

Info

Publication number: JP4164308B2
Application number: JP2002219705A
Authority: JP
Inventors: 喜徳宇野; 勉池田; 宏松田
Original assignee: Canon Inc
Current assignee: Canon Inc
Priority date: 2002-07-29
Filing date: 2002-07-29
Publication date: 2008-10-15
Anticipated expiration: 2022-07-29
Also published as: JP2004061834A

Description

【０００１】
【発明の属する技術分野】
本発明はレンズの光軸上に備え、光量に応じ透過率が変化する光量調整素子とその駆動方法、駆動装置およびこれを用いた装置に関するものである。
【０００２】
【従来の技術】
透過率の異なるフィルタを選択的に光軸上に出し入れして、自動的に光量調整を行うビデオ、カメラ用交換レンズの光量調整装置が特開平０５−０４０２９３に開示されている。係る発明は、透過率の異なる複数のフィルタを保持したフィルタ保持体を鏡筒内に設け、この鏡筒を組み付けたカメラ本体からの情報により前記フィルタ保持体を駆動して適正な光量がえられるように光軸上のフィルタを選択交換する駆動源とを備え、カメラ本体の電源が投入されて撮影待機状態になるときはフィルタ本体を駆動して光量調整動作を行い、カメラ本体が録画状態になったときは光量調整動作を規制する構成とした光量調整装置である。
【０００３】
【発明が解決しようとする課題】
しかしながら、特開平０５−０４０２９３で開示された光量調整装置は
・複数のフィルタとアクチュエーターを保持することから小型化が困難である。・フィルタによる透過率が不連続に変化するため、動画などの撮影中の切替が困難である。もしくは切り替えた場合に不自然な画像となる懸念がある。
といった問題点を抱えている。
【０００４】
【課題を解決するための手段】
本発明者は、以上述べたように問題点を解析し、上記の問題は透過光量を無段階で変化できる素子を１つ備えることで改善できることを見出した。そこで、本発明の目的は、上記の従来技術の問題点を改善し、不透明帯電泳動粒子を電気信号で移動させて透過光量状態を変化させる電気泳動光量調整素子を提供することにある。
【０００５】
本発明の第１は、透過光量を調節する光量調整素子であって、実質的に透明な第一基板と、該第一基板に間隙支持体を介して対向して配置された実質的に透明な第二基板と、前記両基板間に充填された透明絶縁性液体と複数の不透明帯電泳動粒子からなる電気泳動液と、前記両基板の少なくとも一方の対向面側の、平面方向に順次ずれて配置された３以上の電極を含む複数の電極群とを有し、
各電極群中の電極が他の電極群中の相対応する電極と電気的に結線されており、
前記不透明帯電泳動粒子を前記３以上の電極の１つに集める駆動電圧が、前記配置の順に時間的にずれて前記３以上の電極に順次印加されることを特徴とする光量調整素子である。
【０００７】
また、前記の光量調整素子が、前記第１基板または第２基板が非透光性領域と透光性領域とを有し、前記非透光性領域に前記不透明帯電泳動粒子を集合させた透過状態と、前記透光性領域の一部もしくは全部に前記不透明帯電泳動粒子を分散させた半透光状態もしくは非透過状態とを含んで透過光量が調整されることが好ましい。
【０００８】
【発明の実施の形態】
以下、本発明の実施態様について順に説明する。
【０００９】
図１に本発明の代表的な断面構成図を、図７に本発明の代表的な平面図を示す。第一基板１上には第１電極７と第３電極９が配置されており、絶縁部３を挟んで第２電極８と第４電極１０が配置されている。この場合、第１、第２、第３及び第４電極の４電極によって１つの電極群が構成されており、図７に示すように２つの電極群が存在し、各電極が周期的に配列している。さらにその上に間隙支持体４を挟んで第二基板２が配置されている。
【００１０】
第一基板１と第二基板２と間隙支持体４によって作られる空間には透明な絶縁性液体６が充填され、その絶縁性液体６中に電界印加によって泳動する不透明帯電泳動粒子５が分散されている。第１電極７、第２電極８、第３電極９、第４電極１０の平面パターンは環状であり、それを同心円状に配置している。図中にそれぞれ４本ずつ配置された第１電極７、第２電極８、第３電極９、第４電極１０は、それぞれの電極同士が外部で結線され、電気的に接続されている。
【００１１】
第一基板、第二基板は、実質的に光学的に透明である。なお、本発明において、実質的に透明であるとは、光透過率が可視光域（波長４００−７００ｎｍ）或は変調しようとする波長領域において、７０％以上、好ましくは８０％以上、より好ましくは９０％以上であることを意味する。
【００１２】
透明な電極のうち１つの電極群を形成する電極数は、３つ以上ならいくらでも良い。また上記電極群が１つであり、その中の電極数が３の場合を図２に示す。さらにこの電極数は、３電極以上あれば良く、かつ電極群数が複数あり、その電極パターンが周期的に配置されている場合が好ましい。この場合電極上に浮遊する不透明帯電泳動粒子を、一方の電極から他方の電極へ搬送することが可能であり、電極数が３を下回ると動作が不完全となる。
【００１３】
ここで云う周期的とはこの電極群数をＮとすると、第１電極７の平面方向の隣に第２電極８を配置し、その第２電極８の平面方向の隣に第３電極９を配置し、・・・、順次に第ｎ電極の平面方向の隣に再度第１電極７を配置する構成を指す。ただし、電極群数が１つの場合は、第１電極７の平面方向の隣に第２電極８を配置し、その第２電極８の平面方向の隣に第３電極９を配置する構成に従って第ｎ電極までを配置すればよい。また、各電極群に含まれる電極数はすべて等しくなくても良い。ｎを２以上の整数とすると、１電極群の最後の第ｎ電極の隣に、次の電極群に属する第１電極が配置されていれば良い。
【００１４】
電極は一方の基板のみに配置しても良いが両方の基板に配置しても良い。すくなくとも各電極は基板の対向面側に配置し平面方向にずらした位置に配置すればよい。電極は全面を覆うようにに配置するのが好ましいが（図１、図４）、その限りではない。全面を覆ってもいいし覆わなくても良い。つまり電極間に隙間があってよい（図２、図５）。さらには電極同士が一部重複していて配置されても良い（図３）。電極に透明電極を用いるのは好ましい構成だが、電極が全面を覆わない場合は透明電極でなくても良い。電極が全面を覆う場合には少なくとも一部の電極が透明であれば良い。
【００１５】
不透明帯電泳動粒子５は電極に印加された電圧により発生する電場に依存して泳動する。例えば不透明帯電泳動粒子５が正に帯電している場合、不透明帯電泳動粒子５は最も低い電圧が印加された電極近傍に集まる。最も低い電圧を印加する電極を第１電極７、第２電極８・・・と替えると不透明帯電泳動粒子５は第１電極７に集まった後、第２電極８に集まる。これを繰り返すことで不透明帯電泳同粒子５を電気泳動光量調整素子２１内で移動可能となり、不透明帯電泳同粒子５を凝集分散させ電気泳動光量調整素子２１の透過光量を調整できる。また、不透明帯電泳動粒子５を逆方向へ移動させる場合には図１２に示すように印加電圧の位相を逆にすればよい。
【００１６】
駆動電圧の波形は特に限定しない。矩形波（図１０）、正弦波、三角波などどのようの駆動波形でも良い。各電極に印加する駆動波形の位相差も特に限定しないが、均等な位相差をもって入力するのが好ましい（図１１）。例えば電極群数がｎ個の場合、各電極間の位相差は２π／ｎとなる。
【００１７】
不透明帯電泳動粒子５の駆動方法として、実効的な電界強度を徐々に増減させることは良い駆動方法の一つである（図１３）。各電極に印加する電圧の入力波形は正弦波、矩形波などを位相をずらして入力すればよいが、それよりも低い周波数で電圧を増減させて入力しても良い。本素子は第１電極７から第２電極８、第２電極８から第３電極９、第３電極９から・・・と不透明帯電泳動粒子５を移動させて駆動するが、その第１電極７から第２電極８へ移動させる電圧と第２電極８から第３電極９へ移動させる電圧を僅かに変えることで粒子の搬送量を変化させ、粒子を均一に分散可能となる。例えば電圧を以下の式で与えられる値にして入力する駆動方法は１つの例である。
【００１８】
【外１】

【００１９】
（但しｆ：周波数、ｔ：時間、ｎ：電極群の番号、Ｎ：電極群数、α：−１以上１以下の実数）
または図１３に示すように駆動電圧の高さを徐々に低下もしくは増加させるサイクルを繰り返しても良い。
【００２０】
電気泳動調光素子２１の一部に不透明帯電泳動粒子５を集合させて透光状態をなし（図１），電気泳動調光素子２１全体に不透明帯電泳動粒子５を分散させて半透光状態を成す（図２）のは良い駆動方法の１つである。透光状態をなす際に不透明帯電泳動粒子５を集合させる場所は素子内であればどこでも良い。素子中央に集めても良いし、素子周辺部に集めても良い（図１）。または１つ以上の電極群上に集めても良い。
【００２１】
電気泳動調光素子２１の一部に不透明な遮光部１１を備える構成は好ましい構成の１つである（図４、図５、図８、図９）。遮光部１１の構成は特に限定しない。一部が透明で一部が不透明な基板（図３）もしくは不透明な基板に穴をあけたもの（図４、図５）を第一基板１もしくは第二基板２の上に設けてもよいし、第一基板１もしくは第二基板２を不透明に着色しても良い。または一部が不透明な基板を第一基板１もしくは第二基板２に用いても良い。または、不透明の電極材料で電極を作成し遮光部１１としても良い。
【００２２】
遮光領域も特に限定しない。素子中央でもよいし、周辺部分（図８、図９）でも良い。一部を不透明材料で作成した電極を遮光部分としても良い。
【００２３】
遮光部１に不透明帯電泳動粒子５を搬送して透光状態をなし、開口部１２の一部もしくは全部に粒子を搬送して、半透光状態を成す方法は好ましい駆動方法の１つである。遮光部１１に不透明帯電泳動粒子５を集めることで透光状態の透過率が一定になる。また不透明帯電泳動粒子５を開口部１２の全部に分散して半透光状態をなしてもよいし（図８）、開口部１２の一部に移動させて一部透光部分を残して半透光状態にする（図９）のも良い駆動方法である。不透明な電極と一部の透明な電極上に粒子を移動させて半透光状態をなすのも良い駆動方法である。
【００２４】
絶縁部３を介して配置される電極層を２電極層以上備え、２つ以上でかつ全電極群数の半数以下の電極群を１つの電極層に配置することは好ましい構成の１つである。図２に示すように、電極間には絶縁部３もしくは電極間に隙間を作るなど、少なくとも絶縁を保つ部分が必要である。電極を全面に配置する場合、電極層を２つ以上備えかつ全電極群数の半数以下の電極群を１つの電極層に配置することで電極間の隙間の無い構成が可能となる（図１）。また、１つの電極層に２つ以上の電極群を配置することで電極層数を減少でき、製造が容易となる。好ましい構成としては２電極群を備えた電極層を第一基板１および第二基板２に１電極層ずつ（図３）もしくは２電極層ずつ（図４）を備える構成である。
【００２５】
図７は、電極の形状が径の異なる環状で、それぞれの電極を同心に配置する構成は好ましい構成の１つである。電極の太さは特に限定しない。全ての電極で同じでもよいし、例えば電極の径に依存して変化しても良い。また、電極は完全な環でなくても良く、配線をするために環の一部を切断して配線を配置しても良い。環状の電極の最内部に配置される電極は必ずしも環状でなくても良く、例えば円の様に、その電極の内部を電極領域として含んでも良い。
【００２６】
図６は、帯状の電極を配置し、その一部もしくは全部を素子の遠心方向に対して０度でない角度を持って配置する構成は好ましい構成の一つである。電極が遠心方向に対して０度でない角度で配置されることで不透明帯電泳動粒子５を遠心方向と円周方向に同時に搬送することができ、素子内の不透明帯電泳動粒子５の分布濃度を均一化できる。電極と遠心方向の成す角度は特に限定しない。一定でもよいし、素子中心からの距離に依存して変化しても良い。また電極の幅も特に限定しない。一定でもよいし、図６のように素子中心からの距離に依存して変化しても良い。
【００２７】
不透明帯電泳動粒子５を所望の領域に移動させた後に、異なる２つの電圧をそれぞれ１つ以上の電極群に印加し、かつ電圧を交互に入れ替える方法は良い駆動方法の一つである。さらに、不透明帯電泳動粒子５にかかる実効的な電界強度を徐々に低下させて、電極の印加電圧を同じにする駆動方法も好ましい駆動方法である。これらの駆動方法により不透明帯電泳動粒子の分布が均一になり、透過率制御が容易となる。
【００２８】
本素子を用いた好ましい撮像素子の例を図１４に示す。各電極群に所望の電圧を印加する駆動回路２３と素子を通過する光量を測定する光量測定手段２２を備えている。光量測定手段２２はどのようなものでも良い。例えば電荷結合素子などの撮像素子３６を光量測定手段２２に用いて、その出力に依存して適切な透過率になるように駆動回路２３により電気泳動光量調整素子２１を制御すればよい。
【００２９】
またこの電気泳動光量調整素子３５の適用方法は特に限定しないが、レンズ装置３３、撮像モジュール３２、および撮像装置３１などに適用するのは良い適用方法である。一例を図１５に示す。
【００３０】
また本発明の電気泳動光量調整素子は、レンズと撮像素子などの光学部品の光軸上に配置すればその配置方法について特に限定しない。この一例を図１６に示すが、本発明の電気泳動光量調整素子１６５をレンズ装置１６４の絞り位置に対応した場所に配置した例（図１６−ａ）、もしくはレンズ１６４の前面に配置する構成（図１６−ｂ）は好ましい構成例である。
【００３１】
レンズ装置を構成するレンズの枚数は特に限定しない。複数枚で構成しても良いし、１枚でもよい。少なくとも撮像素子に入射する光量を変化させることが出来て、かつ結像面で所望の像が得られればよく、どの位置に配置してもよい。これによってよって結像面に撮像素子１６６を配置することによって、入射光の光量を調節することが可能になる。
【００３２】
【実施例】
以下、実施例に従って本発明を説明する。
【００３３】
（実施例１）
本実施例では、図１に示す断面構成で、図７に示す平面構成の素子を作製し駆動を行った。
【００３４】
作製した素子の大きさは直径１ｍｍ、厚さ０．５３ｍｍである。まず、第一基板１として厚さ０．２ｍｍのガラスにＩＴＯを低温成膜し、フォトリソグラフィー及びエッチングにより図に示す形状にパターニングした。続いて、絶縁部としてＳｉＯ_２を製膜し、その上にＩＴＯを低温成膜し、フォトリソグラフィー及びエッチングにより図に示す形状にパターニングした。また、同様に絶縁部としてＳｉＯ_２を製膜した。この上に、間隙支持体４を形成した。間隙支持体４は、光感光性エポキシ樹脂を塗布した後、露光及びウエット現像を行うことによって形成し、３０μｍの高さとした。形成された空間内に絶縁性液体６及び不透明帯電泳動粒子５を充填した。絶縁性液体６としては、イソパラフィンを使用した。不透明帯電泳動粒子５としては、ポリスチレンとカーボンの混合物で、平均粒径２μｍ位のものを使用した。イソパラフィン中での不透明帯電泳動粒子５は正帯電極性を示した。次に、第２基板２として厚さ０．２ｍｍのガラスを位置合わせを行ないながら第一基板１上に置き、素子周辺部を接着剤により張り合わせた。
【００３５】
これに駆動装置２３を接続して駆動を行った。まず、図１１に示す波形により素子を駆動させたところ、素子全体に分散していた不透明帯電泳動粒子５は素子中央に搬送され透光状態となった。駆動電圧は１０Ｖである。また、図１２に示す波形により素子を駆動させたところ、素子中央に分散していた不透明帯電泳動粒子５は素子周辺に搬送され透光状態となった。駆動電圧は同様に１０Ｖである。
【００３６】
また、図１３に示す波形により素子を駆動させたところ、素子周辺に分散していた不透明帯電泳動粒子５は素子全体に分散され半透光光状態となった。駆動電圧は最高１０Ｖである。また第１電極７と第３電極９、第２電極８と第４電極１０をそれぞれ同電位として、一方に５Ｖ他方に−５Ｖを交互に印加したところ不透明帯電泳動粒子５は均一に分散した。さらに、電圧を緩やかに小さくして全ての電極を０Ｖにしたところより均一に分散した。
【００３７】
この駆動装置に光量測定手段２２を接続し、その光量測定手段２２の出力に依存して上記駆動電圧を選択して印加したところ、電気泳動光量調整素子２１を透過する光量を一定に保つことができた。また、本素子を撮像装置３１に取り付けて駆動させたところ、明所から暗所まで良好な画像を得ることができた。
【００３８】
（実施例２）
本実施例では、図５に示す断面構成で、図６に示す平面構成の素子を作製し駆動を行った。
【００３９】
作製した素子の大きさは直径１ｍｍ、厚さ０．５３ｍｍである。まず、第一基板１として厚さ０．２ｍｍのガラスにＩＴＯを低温成膜し、フォトリソグラフィー及びエッチングにより図に示す形状にパターニングした。続いて、絶縁部としてＳｉＯ_２を製膜した。この上に、間隙支持体４を形成した。間隙支持体４は、光感光性エポキシ樹脂を塗布した後、露光及びウエット現像を行うことによって形成し、３０μｍの高さとした。形成された空間内に絶縁性液体６及び不透明帯電泳動粒子５を充填した。絶縁性液体６としては、イソパラフィンを使用した。不透明帯電泳動粒子５としては、ポリスチレンとカーボンの混合物で、平均粒径２μｍ位のものを使用した。イソパラフィン中での不透明帯電泳動粒子５は正帯電極性を示した。次に、第２基板２として厚さ０．２ｍｍのガラスを位置合わせを行ないながら第一基板１上に置き、素子周辺部を接着剤により張り合わせた。その上に直径０．７ｍｍの穴をあけた不透明な基板を配置して遮光部とした。
【００４０】
これに駆動装置２３を接続して駆動を行った。まず、図１２に示す波形により素子を駆動させたところ、素子全体に分散していた不透明帯電泳動粒子５は素子周辺に搬送され透光状態となった。駆動電圧は１０Ｖである。また、図１３に示す波形により素子を駆動させたところ、素子周辺に分散していた不透明帯電泳動粒子５は素子全体に分散され半透光光状態となった（図８）。駆動電圧は最高１０Ｖである。また、図１１に示す波形により素子を駆動させたところ、素子全体に分散していた不透明帯電泳動粒子５は素子中央に搬送され半透光状態となった（図９）。駆動電圧は同様に１０Ｖである。また第１電極７と第３電極９、第２電極８と第４電極１０をそれぞれ同電位として、一方に５Ｖ他方に−５Ｖを交互に印加したところ不透明帯電泳動粒子５は均一に分散した。さらに、電圧を緩やかに小さくして全ての電極を０Ｖにしたところより均一に分散した。
【００４１】
この駆動装置に光量測定手段２２を接続し、その光量測定手段２２の出力に依存して上記駆動電圧を選択して印加したところ、電気泳動光量調整素子２１を透過する光量を一定に保つことができた。また、本素子を撮像モジュール３２に取り付けて駆動させたところ、明所から暗所まで良好な画像を得ることができた。
【００４２】
【発明の効果】
以上、詳細に述べたように、本発明によって次のような効果が得られた。
第一に、１つの素子で透過率が変化する電気泳動光量調整素子を提供した。これによりこれまで小型化が困難であったレンズ装置、撮像モジュール、撮像装置を大幅に小型化できた。
【００４３】
第二に、無段階で透過率を変化できることから動画の撮影中にも透過率を変えることができ、より良好な動画像の撮影が可能となった。
【図面の簡単な説明】
【図１】本発明の電気泳動光量調整素子の代表的な断面図の一例を示す。
【図２】本発明の電気泳動光量調整素子の代表的な断面図の一例を示す。
【図３】本発明の電気泳動光量調整素子の代表的な断面図の一例を示す。
【図４】本発明の電気泳動光量調整素子の代表的な断面図の一例を示す。
【図５】本発明の電気泳動光量調整素子の代表的な断面図の一例を示す。
【図６】本発明の電気泳動光量調整素子の代表的な平面図の一例を示す。
【図７】本発明の電気泳動光量調整素子の代表的な平面図の一例を示す。
【図８】本発明の電気泳動光量調整素子の代表的な平面図の一例を示す。
【図９】本発明の電気泳動光量調整素子の代表的な平面図の一例を示す。
【図１０】本発明の電気泳動光量調整素子の代表的な駆動方法の一例を示す。
【図１１】本発明の電気泳動光量調整素子の代表的な駆動方法の一例を示す。
【図１２】本発明の電気泳動光量調整素子の代表的な駆動方法の一例を示す。
【図１３】本発明の電気泳動光量調整素子の代表的な駆動方法の一例を示す。
【図１４】本発明の電気泳動光量調整素子の代表的な適用方法の一例を示す。
【図１５】本発明の電気泳動光量調整素子の代表的な適用方法の一例を示す。
【図１６】本発明の電気泳動光量調整素子を用いた撮像装置の一例を示す図である。
【符号の説明】
１第一基板
２第二基板
３絶縁部
４間隙支持体
５不透明帯電泳動粒子
６絶縁性液体
７第１電極
８第２電極
９第３電極
１０第４電極
１１遮光部
１２開口部
２１電気泳動光量調整素子
２２光量測定手段
２３駆動装置
３１撮像装置
３２撮像モジュール
３３レンズ装置
３４レンズ
３５電気泳動光量調整素子
３６撮像素子
３７撮像素子駆動装置
３８駆動装置
３９記憶装置[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a light amount adjusting element which is provided on an optical axis of a lens and whose transmittance changes according to the light amount, a driving method thereof, a driving device, and a device using the same.
[0002]
[Prior art]
Japanese Laid-Open Patent Publication No. 05-040293 discloses a video / camera interchangeable lens light amount adjusting device that automatically adjusts the light amount by selectively inserting and removing filters having different transmittances on and off the optical axis. In this invention, a filter holder holding a plurality of filters having different transmittances is provided in a lens barrel, and an appropriate amount of light is obtained by driving the filter holder according to information from a camera body in which the lens barrel is assembled. A drive source for selectively exchanging the filter on the optical axis, and when the camera body is turned on and enters a shooting standby state, the filter body is driven to adjust the light amount, and the camera body is in a recording state. In this case, the light amount adjusting device is configured to restrict the light amount adjusting operation.
[0003]
[Problems to be solved by the invention]
However, the light amount adjusting device disclosed in Japanese Patent Laid-Open No. 05-040293 is difficult to reduce in size because it holds a plurality of filters and actuators. -Since the transmittance by the filter changes discontinuously, it is difficult to switch during shooting of a moving image or the like. Or, there is a concern that an unnatural image may be generated when switching.
There are problems such as.
[0004]
[Means for Solving the Problems]
The inventor has analyzed the problems as described above and found that the above problems can be improved by providing one element capable of changing the amount of transmitted light in a stepless manner. Accordingly, an object of the present invention is to provide an electrophoretic light amount adjusting element that improves the above-mentioned problems of the prior art and changes the transmitted light amount state by moving the opaque charged electrophoretic particles by an electric signal.
[0005]
A first aspect of the present invention is a light amount adjusting element that adjusts a transmitted light amount, and is a substantially transparent first substrate and a substantially transparent substrate disposed to face the first substrate through a gap support. A second substrate, an electrophoretic liquid composed of a transparent insulating liquid and a plurality of opaque charged electrophoretic particles filled between the two substrates, and at least one opposing surface side of the two substrates being sequentially shifted in the plane direction. A plurality of electrode groups including three or more electrodes arranged,
The electrodes in each electrode group are electrically connected to the corresponding electrodes in the other electrode groups,
The light amount adjusting element is characterized in that a driving voltage for collecting the opaque charged electrophoretic particles to one of the three or more electrodes is sequentially applied to the three or more electrodes while being shifted in time in the order of the arrangement.
[0007]
Further, the light amount adjusting device, the first substrate or the second substrate and a non-translucent regions and the light-transmitting region, said to set an opaque electrophoretic particles in the non-light-transmissive region transmitting state and the said opaque electrophoretic particles transmitted light amount and a translucent state or non-transmissive state is dispersed in a part or all of the light transmitting region is adjusted preferably.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in order.
[0009]
FIG. 1 shows a typical sectional configuration diagram of the present invention, and FIG. 7 shows a typical plan view of the present invention. A first electrode 7 and a third electrode 9 are disposed on the first substrate 1, and a second electrode 8 and a fourth electrode 10 are disposed with the insulating portion 3 interposed therebetween. In this case, one electrode group is constituted by four electrodes of the first, second, third and fourth electrodes, and there are two electrode groups as shown in FIG. 7, and each electrode is periodically arranged. is doing. Furthermore, the 2nd board | substrate 2 is arrange | positioned on both sides of the gap | interval support body 4 on it.
[0010]
A space formed by the first substrate 1, the second substrate 2, and the gap support 4 is filled with a transparent insulating liquid 6, and opaque charged electrophoretic particles 5 that migrate by applying an electric field are dispersed in the insulating liquid 6. ing. The plane patterns of the first electrode 7, the second electrode 8, the third electrode 9, and the fourth electrode 10 are annular, and are arranged concentrically. The first electrode 7, the second electrode 8, the third electrode 9, and the fourth electrode 10 that are arranged four each in the drawing are electrically connected to each other by connecting the electrodes to each other.
[0011]
The first substrate and the second substrate are substantially optically transparent. In the present invention, substantially transparent means that the light transmittance is 70% or more, preferably 80% or more, more preferably in the visible light region (wavelength 400 to 700 nm) or the wavelength region to be modulated. Means 90% or more.
[0012]
Of the transparent electrodes, the number of electrodes forming one electrode group may be any number as long as it is three or more. FIG. 2 shows the case where there is one electrode group and the number of electrodes in the electrode group is three. Further, the number of electrodes may be three or more, and there are a plurality of electrode groups, and the electrode patterns are preferably arranged periodically. In this case, the opaque charged electrophoretic particles floating on the electrode can be transported from one electrode to the other electrode, and when the number of electrodes is less than 3, the operation becomes incomplete.
[0013]
Here, the term “periodic” means that the number of electrode groups is N, the second electrode 8 is arranged next to the first electrode 7 in the plane direction, and the third electrode 9 is arranged next to the second electrode 8 in the plane direction. Arrangement is a configuration in which the first electrode 7 is arranged again next to the n-th electrode in the plane direction. However, when the number of electrode groups is one, the second electrode 8 is arranged next to the first electrode 7 in the plane direction, and the third electrode 9 is arranged next to the second electrode 8 in the plane direction. What is necessary is just to arrange | position to n electrode. Further, the number of electrodes included in each electrode group may not be equal. When n is an integer of 2 or more, it is only necessary that the first electrode belonging to the next electrode group is arranged next to the last n-th electrode of one electrode group.
[0014]
The electrodes may be disposed on only one substrate, but may be disposed on both substrates. At least each electrode may be arranged on the opposite surface side of the substrate and at a position shifted in the plane direction. The electrodes are preferably arranged so as to cover the entire surface (FIGS. 1 and 4), but this is not a limitation. The entire surface may or may not be covered. That is, there may be a gap between the electrodes (FIGS. 2 and 5). Furthermore, the electrodes may be partially overlapped and arranged (FIG. 3). Although it is preferable to use a transparent electrode for the electrode, it may not be a transparent electrode if the electrode does not cover the entire surface. When the electrode covers the entire surface, at least a part of the electrode may be transparent.
[0015]
The opaque charged electrophoretic particles 5 migrate depending on the electric field generated by the voltage applied to the electrodes. For example, when the opaque charged electrophoretic particles 5 are positively charged, the opaque charged electrophoretic particles 5 gather near the electrode to which the lowest voltage is applied. When the electrode to which the lowest voltage is applied is replaced with the first electrode 7, the second electrode 8..., The opaque charged electrophoretic particles 5 gather on the first electrode 7 and then gather on the second electrode 8. By repeating this, the opaque charged swimming particles 5 can be moved within the electrophoretic light amount adjusting element 21, and the opaque charged swimming particles 5 can be aggregated and dispersed to adjust the transmitted light amount of the electrophoretic light amount adjusting element 21. When the opaque charged electrophoretic particles 5 are moved in the reverse direction, the phase of the applied voltage may be reversed as shown in FIG.
[0016]
The waveform of the drive voltage is not particularly limited. Any driving waveform such as a rectangular wave (FIG. 10), a sine wave, or a triangular wave may be used. The phase difference of the drive waveform applied to each electrode is not particularly limited, but it is preferable to input with a uniform phase difference (FIG. 11). For example, when the number of electrode groups is n, the phase difference between the electrodes is 2π / n.
[0017]
As a method for driving the opaque charged electrophoretic particles 5, gradually increasing or decreasing the effective electric field strength is one of the good driving methods (FIG. 13). As the input waveform of the voltage applied to each electrode, a sine wave, a rectangular wave, or the like may be input with the phase shifted, but the voltage may be input with an increased or decreased frequency at a lower frequency. This element is driven by moving the opaque charged electrophoretic particles 5 from the first electrode 7 to the second electrode 8, from the second electrode 8 to the third electrode 9, from the third electrode 9, and so on. By slightly changing the voltage moved from the second electrode 8 to the second electrode 8 and the voltage moved from the second electrode 8 to the third electrode 9, the amount of particles transported can be changed to uniformly disperse the particles. For example, a driving method in which a voltage is input with a value given by the following equation is one example.
[0018]
[Outside 1]

[0019]
(Where f: frequency, t: time, n: number of electrode groups, N: number of electrode groups, α: real number from −1 to 1)
Alternatively, as shown in FIG. 13, a cycle for gradually decreasing or increasing the drive voltage may be repeated.
[0020]
The opaque charged electrophoretic particles 5 are gathered on a part of the electrophoretic light control element 21 to form a translucent state (FIG. 1), and the opaque charged electrophoretic particles 5 are dispersed throughout the electrophoretic light control element 21 so as to be semi-translucent. (Fig. 2) is one of good driving methods. The place where the opaque charged electrophoretic particles 5 are gathered in the light transmitting state may be anywhere within the device. They may be collected at the center of the element or at the periphery of the element (FIG. 1). Or you may collect on one or more electrode groups.
[0021]
A configuration in which the opaque light shielding portion 11 is provided in a part of the electrophoretic light control element 21 is one of preferable configurations (FIGS. 4, 5, 8, and 9). The configuration of the light shielding unit 11 is not particularly limited. A partially transparent and partially opaque substrate (FIG. 3) or an opaque substrate with holes (FIGS. 4 and 5) may be provided on the first substrate 1 or the second substrate 2. The first substrate 1 or the second substrate 2 may be colored opaque. Alternatively, a partially opaque substrate may be used for the first substrate 1 or the second substrate 2. Alternatively, an electrode may be made of an opaque electrode material to form the light shielding part 11.
[0022]
The light shielding area is not particularly limited. The center of the element or the peripheral portion (FIGS. 8 and 9) may be used. An electrode partially made of an opaque material may be used as the light shielding portion.
[0023]
One preferred driving method is a method in which the opaque charged electrophoretic particles 5 are transported to the light-shielding portion 1 to form a light-transmitting state, and the particles are transported to a part or all of the opening 12 to form a semi-light-transmitting state. . By collecting the opaque charged electrophoretic particles 5 in the light shielding portion 11, the transmittance in the light-transmitting state becomes constant. Further, the opaque charged electrophoretic particles 5 may be dispersed in the entire opening 12 to make a semi-translucent state (FIG. 8), or may be moved to a part of the opening 12 to leave a part of the translucent part. It is also a good driving method to make a light-transmitting state (FIG. 9). It is also a good driving method in which particles are moved onto an opaque electrode and some transparent electrodes to make a semi-transparent state.
[0024]
It is one of the preferable configurations that two or more electrode layers are provided via the insulating portion 3 and two or more electrode groups and no more than half of the total number of electrode groups are arranged in one electrode layer. . As shown in FIG. 2, at least a portion that keeps insulation is required between the electrodes, such as an insulating portion 3 or a gap between the electrodes. In the case where the electrodes are arranged on the entire surface, it is possible to provide a configuration with no gap between the electrodes by providing two or more electrode layers and arranging an electrode group that is half or less of the total number of electrode groups in one electrode layer (FIG. 1). ). In addition, by arranging two or more electrode groups in one electrode layer, the number of electrode layers can be reduced, and manufacturing becomes easy. As a preferred configuration, an electrode layer having two electrode groups is provided on the first substrate 1 and the second substrate 2 by one electrode layer (FIG. 3) or two electrode layers (FIG. 4).
[0025]
In FIG. 7, a configuration in which the electrodes are in an annular shape with different diameters and the electrodes are arranged concentrically is one of the preferable configurations. The thickness of the electrode is not particularly limited. It may be the same for all electrodes, or may vary depending on, for example, the diameter of the electrodes. In addition, the electrode may not be a complete ring, and in order to perform wiring, a part of the ring may be cut and the wiring may be arranged. The electrode arranged at the innermost part of the annular electrode does not necessarily have to be annular, and for example, the inside of the electrode may be included as an electrode region like a circle.
[0026]
FIG. 6 shows a preferred configuration in which strip-like electrodes are arranged and a part or all of them are arranged at an angle other than 0 degrees with respect to the centrifugal direction of the element. By arranging the electrodes at an angle other than 0 degrees with respect to the centrifugal direction, the opaque charged electrophoretic particles 5 can be simultaneously conveyed in the centrifugal direction and the circumferential direction, and the distribution concentration of the opaque charged electrophoretic particles 5 in the element is uniform. Can be The angle formed between the electrode and the centrifugal direction is not particularly limited. It may be constant or may vary depending on the distance from the element center. Further, the width of the electrode is not particularly limited. It may be constant or may vary depending on the distance from the element center as shown in FIG.
[0027]
A method of moving the opaque charged electrophoretic particles 5 to a desired region and then applying two different voltages to one or more electrode groups and alternately switching the voltages is one of good driving methods. Further, a driving method in which the effective electric field strength applied to the opaque charged electrophoretic particles 5 is gradually decreased to make the applied voltage of the electrodes the same is also a preferable driving method. By these driving methods, the distribution of the opaque charged electrophoretic particles becomes uniform, and the transmittance control becomes easy.
[0028]
An example of a preferable image sensor using this element is shown in FIG. A drive circuit 23 for applying a desired voltage to each electrode group and a light amount measuring means 22 for measuring the amount of light passing through the element are provided. Any light quantity measuring means 22 may be used. For example, the electrophoretic light amount adjusting element 21 may be controlled by the driving circuit 23 so that the image sensor 36 such as a charge coupled device is used as the light amount measuring unit 22 and the appropriate transmittance is obtained depending on the output.
[0029]
The application method of the electrophoretic light amount adjustment element 35 is not particularly limited, but it is a good application method to be applied to the lens device 33, the imaging module 32, the imaging device 31, and the like. An example is shown in FIG.
[0030]
The electrophoretic light amount adjusting element of the present invention is not particularly limited as to the arrangement method as long as it is arranged on the optical axis of an optical component such as a lens and an imaging element. An example of this is shown in FIG. 16, and an example in which the electrophoretic light amount adjusting element 165 of the present invention is disposed at a location corresponding to the aperture position of the lens device 164 (FIG. 16-a), or a configuration in which the electrophoretic light amount adjusting element 165 is disposed in front of the lens 164 FIG. 16B) is a preferred configuration example.
[0031]
The number of lenses constituting the lens device is not particularly limited. It may be composed of a plurality of sheets or a single sheet. As long as at least the amount of light incident on the image sensor can be changed and a desired image can be obtained on the imaging plane, it may be arranged at any position. Accordingly, it is possible to adjust the amount of incident light by disposing the image sensor 166 on the image plane.
[0032]
【Example】
Hereinafter, the present invention will be described according to examples.
[0033]
(Example 1)
In this example, an element having the cross-sectional configuration shown in FIG. 1 and the planar configuration shown in FIG. 7 was produced and driven.
[0034]
The size of the manufactured element is 1 mm in diameter and 0.53 mm in thickness. First, an ITO film was formed at a low temperature on a glass having a thickness of 0.2 mm as the first substrate 1 and patterned into a shape shown in the figure by photolithography and etching. Subsequently, SiO ₂ was formed as an insulating portion, ITO was formed thereon at a low temperature, and was patterned into a shape shown in the figure by photolithography and etching. Similarly, SiO ₂ was formed as an insulating part. On this, the gap | interval support body 4 was formed. The gap support 4 was formed by applying a photosensitive epoxy resin and then performing exposure and wet development to a height of 30 μm. The formed space was filled with the insulating liquid 6 and the opaque charged electrophoretic particles 5. Isoparaffin was used as the insulating liquid 6. As the opaque charged electrophoretic particles 5, a mixture of polystyrene and carbon having an average particle size of about 2 μm was used. The opaque charged electrophoretic particles 5 in isoparaffin showed positively charged polarity. Next, a glass having a thickness of 0.2 mm was placed on the first substrate 1 as the second substrate 2 while being aligned, and the peripheral portion of the element was bonded with an adhesive.
[0035]
The drive device 23 was connected to this for driving. First, when the device was driven by the waveform shown in FIG. 11, the opaque charged electrophoretic particles 5 dispersed throughout the device were transported to the center of the device and became translucent. The driving voltage is 10V. Further, when the device was driven by the waveform shown in FIG. 12, the opaque charged electrophoretic particles 5 dispersed in the center of the device were transported to the periphery of the device and became translucent. The drive voltage is similarly 10V.
[0036]
Further, when the device was driven by the waveform shown in FIG. 13, the opaque charged electrophoretic particles 5 dispersed around the device were dispersed throughout the device and became a semi-translucent light state. The driving voltage is a maximum of 10V. Further, when the first electrode 7 and the third electrode 9, the second electrode 8 and the fourth electrode 10 were set to the same potential, and 5V was applied to one side and -5V was applied alternately to the other, the opaque charged electrophoretic particles 5 were uniformly dispersed. Furthermore, when the voltage was gradually reduced to make all the electrodes 0 V, the dispersion was more uniform.
[0037]
When the light quantity measuring means 22 is connected to this driving device, and the drive voltage is selected and applied depending on the output of the light quantity measuring means 22, the light quantity transmitted through the electrophoretic light quantity adjusting element 21 can be kept constant. did it. Further, when this element was attached to the image pickup apparatus 31 and driven, a good image could be obtained from a bright place to a dark place.
[0038]
(Example 2)
In this example, an element having the cross-sectional configuration shown in FIG. 5 and the planar configuration shown in FIG. 6 was produced and driven.
[0039]
The size of the manufactured element is 1 mm in diameter and 0.53 mm in thickness. First, an ITO film was formed at a low temperature on a glass having a thickness of 0.2 mm as the first substrate 1 and patterned into a shape shown in the figure by photolithography and etching. Subsequently, SiO ₂ was formed as an insulating part. On this, the gap | interval support body 4 was formed. The gap support 4 was formed by applying a photosensitive epoxy resin and then performing exposure and wet development to a height of 30 μm. The formed space was filled with the insulating liquid 6 and the opaque charged electrophoretic particles 5. Isoparaffin was used as the insulating liquid 6. As the opaque charged electrophoretic particles 5, a mixture of polystyrene and carbon having an average particle size of about 2 μm was used. The opaque charged electrophoretic particles 5 in isoparaffin showed positively charged polarity. Next, a glass having a thickness of 0.2 mm was placed on the first substrate 1 as the second substrate 2 while being aligned, and the peripheral portion of the element was bonded with an adhesive. An opaque substrate with a hole having a diameter of 0.7 mm was disposed thereon to form a light shielding part.
[0040]
The drive device 23 was connected to this for driving. First, when the device was driven by the waveform shown in FIG. 12, the opaque charged electrophoretic particles 5 dispersed throughout the device were transported to the periphery of the device and became translucent. The driving voltage is 10V. Further, when the device was driven by the waveform shown in FIG. 13, the opaque charged electrophoretic particles 5 dispersed around the device were dispersed throughout the device to be in a semi-translucent light state (FIG. 8). The driving voltage is a maximum of 10V. Further, when the device was driven by the waveform shown in FIG. 11, the opaque charged electrophoretic particles 5 dispersed throughout the device were transported to the center of the device and became semi-translucent (FIG. 9). The drive voltage is similarly 10V. Further, when the first electrode 7 and the third electrode 9, the second electrode 8 and the fourth electrode 10 were set to the same potential, and 5V was applied to one side and -5V was applied alternately to the other, the opaque charged electrophoretic particles 5 were uniformly dispersed. Furthermore, when the voltage was gradually reduced to make all the electrodes 0 V, the dispersion was more uniform.
[0041]
When the light quantity measuring means 22 is connected to this driving device, and the drive voltage is selected and applied depending on the output of the light quantity measuring means 22, the light quantity transmitted through the electrophoretic light quantity adjusting element 21 can be kept constant. did it. Further, when this element was attached to the image pickup module 32 and driven, a good image could be obtained from a bright place to a dark place.
[0042]
【The invention's effect】
As described above in detail, the present invention has the following effects.
First, an electrophoretic light amount adjusting element in which the transmittance is changed by one element is provided. As a result, the lens device, the imaging module, and the imaging device that have been difficult to miniaturize can be greatly reduced in size.
[0043]
Secondly, since the transmittance can be changed in a stepless manner, the transmittance can be changed even during shooting of a moving image, and a better moving image can be shot.
[Brief description of the drawings]
FIG. 1 shows an example of a typical sectional view of an electrophoretic light amount adjusting element of the present invention.
FIG. 2 shows an example of a typical sectional view of an electrophoretic light amount adjusting element of the present invention.
FIG. 3 shows an example of a typical sectional view of an electrophoretic light amount adjusting element of the present invention.
FIG. 4 shows an example of a typical sectional view of an electrophoretic light amount adjusting element of the present invention.
FIG. 5 shows an example of a typical sectional view of an electrophoretic light amount adjusting element of the present invention.
FIG. 6 shows an example of a typical plan view of an electrophoretic light amount adjusting element of the present invention.
FIG. 7 shows an example of a typical plan view of an electrophoretic light amount adjusting element of the present invention.
FIG. 8 shows an example of a typical plan view of an electrophoretic light amount adjusting element of the present invention.
FIG. 9 shows an example of a typical plan view of an electrophoretic light amount adjusting element of the present invention.
FIG. 10 shows an example of a typical driving method of the electrophoretic light amount adjusting element of the present invention.
FIG. 11 shows an example of a typical driving method of the electrophoretic light amount adjusting element of the present invention.
FIG. 12 shows an example of a typical driving method of the electrophoretic light amount adjusting element of the present invention.
FIG. 13 shows an example of a typical driving method of the electrophoretic light amount adjusting element of the present invention.
FIG. 14 shows an example of a typical application method of the electrophoretic light amount adjusting element of the present invention.
FIG. 15 shows an example of a typical application method of the electrophoretic light amount adjusting element of the present invention.
FIG. 16 is a diagram illustrating an example of an imaging apparatus using the electrophoretic light amount adjusting element of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 1st board | substrate 2 2nd board | substrate 3 Insulating part 4 Gap support body 5 Opaque charged electrophoretic particle 6 Insulating liquid 7 1st electrode 8 2nd electrode 9 3rd electrode 10 4th electrode 11 Light-shielding part 12 Opening part 21 Electrophoretic light quantity Adjusting element 22 Light quantity measuring means 23 Driving device 31 Imaging device 32 Imaging module 33 Lens device 34 Lens 35 Electrophoretic light quantity adjusting element 36 Imaging element 37 Imaging element driving device 38 Driving device 39 Storage device

Claims

A light amount adjusting element for adjusting a transmitted light amount,
A substantially transparent first substrate, a substantially transparent second substrate disposed opposite to the first substrate via a gap support, and a transparent insulating liquid filled between the substrates. An electrophoretic liquid composed of a plurality of opaque charged electrophoretic particles, and a plurality of electrode groups including three or more electrodes arranged sequentially shifted in a plane direction on at least one opposing surface side of the both substrates,
The electrodes in each electrode group are electrically connected to the corresponding electrodes in the other electrode groups,
A light amount adjusting element, wherein a driving voltage for collecting the opaque charged electrophoretic particles to one of the three or more electrodes is sequentially applied to the three or more electrodes in a time-shifted order.

The first substrate or the second substrate has a non-translucent region and a translucent region, a transmission state in which the opaque charged electrophoretic particles are aggregated in the non-translucent region, and the translucent region The light amount adjusting element according to claim 1, wherein the transmitted light amount is adjusted to include a semi-transparent state or a non-transparent state in which the opaque charged electrophoretic particles are partly or entirely dispersed.

The light quantity adjusting element according to claim 2, wherein the non-translucent region is formed of a light shielding member.

The light quantity adjusting element according to claim 1, wherein the three or more electrodes are formed on both the first substrate and the second substrate.

The light quantity adjusting element according to claim 1, wherein the three or more electrodes are formed across a plurality of layers via an insulating layer on either the first substrate or the second substrate.

The light quantity adjusting element according to claim 1, wherein the pattern of the three or more electrodes is annular and arranged concentrically.

An image pickup apparatus comprising: the light amount adjustment element according to claim 1; a lens; an image pickup element; a drive circuit for the image pickup element; and a drive circuit for the light adjustment element.