JP4111809B2 - Electrostatic actuator, droplet discharge head and manufacturing method thereof, ink cartridge, inkjet recording apparatus, micropump, optical device, image forming apparatus, and apparatus for discharging droplets - Google Patents

Description

【００５４】
なお、（１）式において、Ｆ：電極間に働く力、ε：誘電率、Ｓ：電極の対向する面の面積、ｄ：電極間距離、Ｖ：印加電圧である。
【００５５】
そこで、前述したように犠牲層エッチングで空隙２３を形成することにより、高精度に微小なギャップを形成することができる。そして、この犠牲層エッチングで犠牲層を除去するための犠牲層除去孔を封止材が空隙に入り込まない状態で封止することにより、アクチュエータの特性バラツキが少なくなって安定した動作特性が得られ、これにより安定した滴吐出特性を得ることができる。
【００５６】
さらに、空隙を形成するため振動板に形成されている犠牲層除去孔がアクチュエータを構成する材料で封止されることで、空隙内への異物、汚染物質の侵入を製造工程で防ぐことができ、信頼性の高いアクチュエータを得ることができる。
【００５７】
これにより、性能バラツキがなく、高精度で高信頼性を具備した液滴吐出ヘッド或いはアクチュエータを低コストで得ることができるようになる。
【００５８】
次に、本発明に係る製造方法を実施したこのインクジェットヘッドの製造工程の第１例について図７及び図８を参照して説明する。なお、両図は同ヘッドのアクチュエータ基板の製造工程の説明に供する断面説明図である。
先ず、図７（ａ）に示すように、厚さ４００μｍのベース基板であるＳｉ基板２１上に絶縁膜（熱酸化膜）２５を１．６μｍ厚に形成する。そして、下部電極材としてＰドープポリシリコンを０．４μｍ厚に成膜し、リソエッチ法で分離溝を形成して電極２４と隔壁部２６とに分離する。
【００５９】
その後、電極２４と隔壁部２６上にＣＶＤ酸化膜である保護膜２７を０．２μｍ堆積させる。この保護膜２７は、犠牲層プロセスでの電極２４を保護するマスク材となるとともに、電極２４と振動板２２を構成する電極膜３６との短絡を防止する保護膜として機能する。
【００６０】
次に、同図（ｂ）に示すように、犠牲層（ノンドープポリシリコン）を空隙間隔となる０．２μｍ厚で、ＣＶＤ法によって成膜し、リソエッチ法により空隙２３となる領域と隔壁部２８となる領域に分離する。なお、電極２４の配線層として隔壁部２６を用いる場合は、隔壁部２８のみをリソ法でレジストパターニングで開口しイオン注入とデンシファイ法を用いて低抵抗化させておく。
【００６１】
その後、保護膜（ＣＶＤ酸化膜）３５を０．１μｍ厚に堆積させる。この保護膜３５は、犠牲層プロセスでの振動板２２を構成する電極膜３６を保護するマスク材となるとともに、電極２４と電極膜３６との短絡を防止する保護膜として機能する。
【００６２】
次いで、同図（ｃ）に示すように、電極材料としてＰドープドポリシリコンを０．２μｍ厚に堆積させ、リソエッチ法で電極膜３６となる領域と隔壁部３９となる領域に分離する。このとき、同時に、犠牲層除去時に犠牲層と同じ材質の電極膜３６がエッチングされないように保護孔（開口部）４２を、犠牲層除去孔４１より大きく開口する。そして、電極膜３６上に振動板２２を構成する撓み防止膜３７としての窒化膜をＣＶＤ法で０．２μｍ厚に堆積させる。
【００６３】
その後、図８（ａ）に示すように、窒化膜（撓み防止膜）３７および絶縁膜３５にリソエッチ法で犠牲層除去孔４１を形成する。レジストを除去した後、同図（ｂ）に示すように、犠牲層５１と窒化膜（撓み防止膜）３７および絶縁膜３５のエッチレート選択性の高い処理方法、例えばＳＦ_６の等方性ドライエッチ法や、あるいはＸｅＦ_２ドライエッチ法で犠牲層５１を完全除去し、空隙２３を形成する。
【００６４】
そして、同図（ｃ）に示すように、接液膜となる樹脂膜３８としてのＰＢＯ膜（ポリベンゾオキサゾール）をスピンコート法で１μｍ厚で形成する。このとき、犠牲層除去孔４１は、ＰＢＯ膜（樹脂膜）３８で完全に封止される。その後、電極配線取りだしパッド部のみリソエッチ法で開口する。
【００６５】
以上で、アクチュエータ基板１１が完成するので、これに流路板１２及びノズル板２を接合して液滴吐出ヘッドを完成する。
【００６６】
なお、樹脂膜（ここでは、接液膜となる。）として、ＰＢＯ膜を例に挙げたが、インクに対して耐腐食性があり、かつ犠牲層除去孔を封止できる膜、例えばポリイミド膜などでもよい。
【００６７】
ＰＢＯ膜のような樹脂膜は、大気中で犠牲層除去孔４１を封止できるため、真空装置を用いたＰＶＤ法やＣＶＤ法で成膜した膜のように空隙が真空封止され、大気暴露することにより空隙内が負圧になり振動板が撓み所望する変位量が得られないというような不具合が生ずることはない。
【００６８】
次に、このインクジェットヘッドの製造工程の第２例について図９及び図１０を参照して説明する。なお、両図は同ヘッドのアクチュエータ基板の製造工程の説明に供する断面説明図である。
先ず、図９（ａ）〜（ｃ）に示す工程は前記第１例の図７（ａ）〜（ｃ）に示す工程と同様である。すなわち、図９（ａ）に示すように、厚さ４００μｍのベース基板であるＳｉ基板２１上に絶縁膜（熱酸化膜）２５を１．６μｍ厚に形成する。そして、下部電極材としてＰドープポリシリコンを０．４μｍ厚に成膜し、リソエッチ法で分離溝を形成して電極２４と隔壁部２６とに分離する。
【００６９】
その後、電極２４と隔壁部２６上にＣＶＤ酸化膜である保護膜２７を０．２μｍ堆積させる。この保護膜２７は、犠牲層プロセスでの電極２４を保護するマスク材となるとともに、電極２４と振動板２２を構成する電極膜３６との短絡を防止する保護膜として機能する。
【００７０】
次に、同図（ｂ）に示すように、犠牲層（ノンドープポリシリコン）を空隙間隔となる０．２μｍ厚で、ＣＶＤ法によって成膜し、リソエッチ法により空隙２３となる領域と隔壁部２８となる領域に分離する。なお、電極２４の配線層として隔壁部２６を用いる場合は、隔壁部２８のみをリソ法でレジストパターニングで開口しイオン注入とデンシファイ法を用いて低抵抗化させておく。
【００７１】
その後、保護膜（ＣＶＤ酸化膜）３５を０．１μｍ厚に堆積させる。この保護膜３５は、犠牲層プロセスでの振動板２２を構成する電極膜３６を保護するマスク材となるとともに、電極２４と電極膜３６との短絡を防止する保護膜として機能する。
【００７２】
次いで、同図（ｃ）に示すように、電極材料としてＰドープドポリシリコンを０．２μｍ厚に堆積させ、リソエッチ法で電極膜３６となる領域と隔壁部３９となる領域に分離する。このとき、同時に、犠牲層除去時に犠牲層と同じ材質の電極膜３６がエッチングされないように保護孔（開口部）４２を、犠牲層除去孔４１より大きく開口する。そして、電極膜３６上に振動板２２を構成する撓み防止膜３７としての窒化膜をＣＶＤ法で０．２μｍ厚に堆積させる。
【００７３】
その後、図１０（ａ）に示すように、レジスト５２でマスクを形成して、窒化膜（撓み防止膜）３７および絶縁膜３５にリソエッチ法で犠牲層除去孔４１を形成する。そして、レジスト５２を除去しないまま、同図（ｂ）に示すように、犠牲層５１と窒化膜（撓み防止膜）３７および絶縁膜３５のエッチレート選択性の高い処理方法、例えばＳＦ_６の等方性ドライエッチ法や、あるいはＸｅＦ_２ドライエッチ法で犠牲層５１を完全除去し、空隙２３を形成する。
【００７４】
そして、同図（ｃ）に示すように、レジスト５２を除去した後、樹脂膜３８としてのＰＢＯ膜（ポリベンゾオキサゾール）を塗布する。このとき、ＰＢＯ膜（樹脂膜）３８が犠牲層除去孔４１から空隙２３内に入り込む可能性があるため、ＰＢＯ膜（樹脂膜）３８を形成する前に、窒化膜（撓み防止膜）３７の表面を改質する。
【００７５】
この樹脂膜３８を形成する膜である撓み防止膜３７の表面の改質は、例えば、ＳＦ_６プラズマに晒すことにより行う。これにより、ＰＢＯ膜３８に対する濡れ性が低下して、ＰＢＯ膜（樹脂膜）３８が犠牲層除去孔４１から空隙２３内に入り込むことが防止され、犠牲層除去孔４１を空隙２３内に入り込むことなく封止できる。
【００７６】
以上で、アクチュエータ基板１１が完成するので、これに流路板１２及びノズル板２を接合して液滴吐出ヘッドを完成する。
【００７７】
これらの第１例及び第２例は、いずれも、樹脂膜３８であるＰＢＯ膜を塗布するときの塗布面は、撓み防止膜３７である窒化膜である。この窒化膜は、レジスト除去時の酸素プラズマに曝されると、ＰＢＯ膜３８との濡れ性が向上し、犠牲層除去孔４１よりＰＢＯ膜３８が空隙２３内へ染込む傾向にある。
【００７８】
そこで、この窒化膜表面、すなわち、樹脂膜を形成する膜の表面をＳＦ_６等のフッ素を含むプラズマに曝すことにより、ＰＢＯ膜３８との濡れ性が低下し、ＰＢＯ膜３８の空隙２３内ヘの染込みを防止できる。この場合、第１例では、犠牲層除去時にＳＦ_６等のガスに曝すようにして、犠牲層除去と表面改質を同時に行なっている。また、第２例では、レジスト除去後に表面改質処理を行なっている。
【００７９】
いずれも、樹脂膜を形成する膜の表面にフッ素が含まれることにより、樹脂膜との濡れ性を低下して、犠牲層除去孔の封止マージンが向上して歩留まりが向上し、品質が向上する。そして、このように、樹脂膜を形成する膜表面にフッ素が含まれる状態にするには、半導体製造で一般的に用いられているフッ素化合物ガス及び装置を用いることで行うことができ、特別な装置は必要でなく、既存の設備で対応が可能なため、安定した表面改質処理が可能となる。
【００８０】
この他、ＰＢＯ膜との濡れ性を低下させる手段として、二弗化キセノンガス雰囲気化に曝す方法もある。この場合は、ガス雰囲気に曝すだけなので、プラズマ処理のような高価な装置が必要でなく、表面改質処理が行なえる利点がある。
【００８１】
また、第１例では、空隙２３を形成する犠牲層エッチング時に振動板表面である窒化膜（撓み防止膜）３７が露出しているため、１００ｎｍ前後エッチングされることを考慮し、成膜時の窒化膜の膜厚を設定する必要がある。また、窒化膜の膜厚バラツキが犠牲層エッチンング時に生ずるため、精度良くアクチュエータを形成する上では不利となり得る。
【００８２】
これに対し、第２例では、犠牲層除去時振動板表面がレジスト５２で保護されており、レジスト除去後の表面処理では、窒化膜がほとんど エッチングされることはなく形成されるため、第１例に比べ精度良くアクチュエータを形成することができる。
【００８３】
次に、このインクジェットヘッドの製造工程の第３例について図１１及び図１２を参照して説明する。なお、両図は同ヘッドのアクチュエータ基板の製造工程の説明に供する断面説明図である。
先ず、図１１（ａ）、（ｂ）に示す工程は前記第１例の図７（ａ）〜（ｃ）に示す工程と同様である。すなわち、図１１（ａ）に示すように、厚さ４００μｍのベース基板であるＳｉ基板２１上に絶縁膜（熱酸化膜）２５を１．６μｍ厚に形成する。そして、下部電極材としてＰドープポリシリコンを０．４μｍ厚に成膜し、リソエッチ法で分離溝を形成して電極２４と隔壁部２６とに分離する。
【００８４】
その後、電極２４と隔壁部２６上にＣＶＤ酸化膜である保護膜２７を０．２μｍ堆積させる。この保護膜２７は、犠牲層プロセスでの電極２４を保護するマスク材となるとともに、電極２４と振動板２２を構成する電極膜３６との短絡を防止する保護膜として機能する。
【００８５】
次に、同図（ｂ）に示すように、犠牲層（ノンドープポリシリコン）を空隙間隔となる０．２μｍ厚で、ＣＶＤ法によって成膜し、リソエッチ法により空隙２３となる領域と隔壁部２８となる領域に分離する。なお、電極２４の配線層として隔壁部２６を用いる場合は、隔壁部２８のみをリソ法でレジストパターニングで開口しイオン注入とデンシファイ法を用いて低抵抗化させておく。
【００８６】
その後、保護膜（ＣＶＤ酸化膜）３５を０．１μｍ厚に堆積させる。この保護膜３５は、犠牲層プロセスでの振動板２２を構成する電極膜３６を保護するマスク材となるとともに、電極２４と電極膜３６との短絡を防止する保護膜として機能する。
【００８７】
次いで、同図（ｃ）に示すように、電極材料としてＰドープドポリシリコンを０．２μｍ厚に堆積させ、リソエッチ法で電極膜３６となる領域と隔壁部３９となる領域に分離する。このとき、同時に、犠牲層除去時に犠牲層と同じ材質の電極膜３６がエッチングされないように保護孔（開口部）４２を、犠牲層除去孔４１より大きく開口する。そして、電極膜３６上に振動板２２を構成する撓み防止膜３７としての窒化膜をＣＶＤ法で０．２μｍ厚に堆積させる。さらに、窒化膜（撓み防止膜）３７上に保護膜（ＣＶＤ酸化膜）５３を０．０５μｍ厚に堆積させる。
【００８８】
その後、図１２（ａ）に示すように、レジスト５２でマスクを形成して、窒化膜（撓み防止膜）３７および絶縁膜３５にリソエッチ法で犠牲層除去孔４１を形成する。そして、レジスト５２を除去しないまま、同図（ｂ）に示すように、犠牲層５１と窒化膜（撓み防止膜）３７および絶縁膜３５のエッチレート選択性の高い処理方法、例えばＳＦ_６の等方性ドライエッチ法や、あるいはＸｅＦ_２ドライエッチ法で犠牲層５１を完全除去し、空隙２３を形成する。
【００８９】
そして、同図（ｃ）に示すように、レジスト５２を除去した後、樹脂膜３８としてのＰＢＯ膜（ポリベンゾオキサゾール）を塗布する。ＰＢＯ膜３８は犠牲層除去孔４１から空隙２３内へ染込むことは無く、犠牲層除去孔４１を封止する。
【００９０】
この第３例では、ＰＢＯ膜３８を塗布する面は、ＣＶＤ酸化膜５３であり、前記第１、第２例の窒化膜と異なり、表面改質処理を行なわずとも、ＰＢＯ膜３８が空隙２３内へ染込むことはなく、表面改質の工程を必要としない。
【００９１】
次に、本発明に係るインクカートリッジついて図１３を参照して説明する。
このインクカートリッジ１００は、ノズル孔１０１等を有する本発明に係る液滴吐出ヘッドであるインクジェットヘッド１０２と、このインクジェットヘッド１０１に対してインクを供給するインクタンク１０３とを一体化したものである。
【００９２】
このように本発明に係る液滴吐出ヘッドにインクを供給するインクタンクを一体化することにより、滴吐出特性のバラツキが少なく、信頼性の高い液滴吐出ヘッドを一体化したインクカートリッジ（インクタンク一体型ヘッド）が低コストで得られる。
【００９３】
次に、本発明に係る液滴吐出ヘッドであるインクジェットヘッドを搭載した本発明に係る液滴を吐出する装置を含む、画像形成装置としてのインクジェット記録装置の機構の一例について図１４及び図１５を参照して説明する。なお、図１４は同記録装置の斜視説明図、図１５は同記録装置の機構部の側面説明図である。
【００９４】
このインクジェット記録装置は、記録装置本体１１１の内部に主走査方向に移動可能なキャリッジ、キャリッジに搭載した本発明に係るインクジェットヘッドからなる記録ヘッド、記録ヘッドへインクを供給するインクカートリッジ等で構成される印字機構部１１２等を収納し、装置本体１１１の下方部には前方側から多数枚の用紙１１３を積載可能な給紙カセット（或いは給紙トレイでもよい。）１１４を抜き差し自在に装着することができ、また、用紙１１３を手差しで給紙するための手差しトレイ１１５を開倒することができ、給紙カセット１１４或いは手差しトレイ１１５から給送される用紙１１３を取り込み、印字機構部１１２によって所要の画像を記録した後、後面側に装着された排紙トレイ１１６に排紙する。
【００９５】
印字機構部１１２は、図示しない左右の側板に横架したガイド部材である主ガイドロッド１２１と従ガイドロッド１２２とでキャリッジ１２３を主走査方向に摺動自在に保持し、このキャリッジ１２３にはイエロー（Ｙ）、シアン（Ｃ）、マゼンタ（Ｍ）、ブラック（Ｂｋ）の各色のインク滴を吐出する本発明に係る液滴吐出ヘッドであるインクジェットヘッドからなるヘッド１２４を複数のインク吐出口を主走査方向と交叉する方向に配列し、インク滴吐出方向を下方に向けて装着している。またキャリッジ１２３にはヘッド１２４に各色のインクを供給するための各インクカートリッジ１２５を交換可能に装着している。なお、本発明に係るインクカートリッジ１００を搭載する構成とすることもできる。
【００９６】
インクカートリッジ１２５は上方に大気と連通する大気口、下方にはインクジェットヘッドへインクを供給する供給口を、内部にはインクが充填された多孔質体を有しており、多孔質体の毛管力によりインクジェットヘッドへ供給されるインクをわずかな負圧に維持している。
【００９７】
また、記録ヘッドとしてここでは各色のヘッド１２４を用いているが、各色のインク滴を吐出するノズルを有する１個のヘッドでもよい。
【００９８】
ここで、キャリッジ１２３は後方側（用紙搬送方向下流側）を主ガイドロッド１２１に摺動自在に嵌装し、前方側（用紙搬送方向上流側）を従ガイドロッド１２２に摺動自在に載置している。そして、このキャリッジ１２３を主走査方向に移動走査するため、主走査モータ１２７で回転駆動される駆動プーリ１２８と従動プーリ１２９との間にタイミングベルト１３０を張装し、このタイミングベルト１３０をキャリッジ１２３に固定しており、主走査モーター１２７の正逆回転によりキャリッジ１２３が往復駆動される。
【００９９】
一方、給紙カセット１１４にセットした用紙１１３をヘッド１２４の下方側に搬送するために、給紙カセット１１４から用紙１１３を分離給装する給紙ローラ１３１及びフリクションパッド１３２と、用紙１１３を案内するガイド部材１３３と、給紙された用紙１１３を反転させて搬送する搬送ローラ１３４と、この搬送ローラ１３４の周面に押し付けられる搬送コロ１３５及び搬送ローラ１３４からの用紙１１３の送り出し角度を規定する先端コロ１３６とを設けている。搬送ローラ１３４は副走査モータ１３７によってギヤ列を介して回転駆動される。
【０１００】
そして、キャリッジ１２３の主走査方向の移動範囲に対応して搬送ローラ１３４から送り出された用紙１１３を記録ヘッド１２４の下方側で案内する用紙ガイド部材である印写受け部材１３９を設けている。この印写受け部材１３９の用紙搬送方向下流側には、用紙１１３を排紙方向へ送り出すために回転駆動される搬送コロ１４１、拍車１４２を設け、さらに用紙１１３を排紙トレイ１１６に送り出す排紙ローラ１４３及び拍車１４４と、排紙経路を形成するガイド部材１４５，１４６とを配設している。
【０１０１】
記録時には、キャリッジ１２３を移動させながら画像信号に応じて記録ヘッド１２４を駆動することにより、停止している用紙１１３にインクを吐出して１行分を記録し、用紙１１３を所定量搬送後次の行の記録を行う。記録終了信号または、用紙１１３の後端が記録領域に到達した信号を受けることにより、記録動作を終了させ用紙１１３を排紙する。
【０１０２】
また、キャリッジ１２３の移動方向右端側の記録領域を外れた位置には、ヘッド１２４の吐出不良を回復するための回復装置１４７を配置している。回復装置１４７はキャップ手段と吸引手段とクリーニング手段を有している。キャリッジ１２３は印字待機中にはこの回復装置１４７側に移動されてキャッピング手段でヘッド１２４をキャッピングされ、吐出口部を湿潤状態に保つことによりインク乾燥による吐出不良を防止する。また、記録途中などに記録と関係しないインクを吐出することにより、全ての吐出口のインク粘度を一定にし、安定した吐出性能を維持する。
【０１０３】
吐出不良が発生した場合等には、キャッピング手段でヘッド１２４の吐出口（ノズル）を密封し、チューブを通して吸引手段で吐出口からインクとともに気泡等を吸い出し、吐出口面に付着したインクやゴミ等はクリーニング手段により除去され吐出不良が回復される。また、吸引されたインクは、本体下部に設置された廃インク溜（不図示）に排出され、廃インク溜内部のインク吸収体に吸収保持される。
【０１０４】
このように、このインクジェット記録装置においては本発明に係る液滴吐出ヘッドであるインクジェットヘッドを搭載しているので、インク滴の吐出特性のバラツキが少なく、高い画像品質の画像を記録できる記録装置が得られる。
【０１０５】
次に、本発明に係る静電型アクチュエータを備えたマイクロデバイスとしてのマイクロポンプについて図１６を参照して説明する。なお、同図は同マイクロポンプの要部断面説明図である。
このマイクロポンプは、流路基板２０１と本発明に係る静電型アクチュエータを構成するアクチュエータ基板２０２とを有している。流路基板２０１には流体が流れる流路２０３を形成している。アクチュエータ基板２０２は、ベース基板２２１上に設けた、流路２０１の壁面を形成する変形可能な振動板（可動板）２２２と、この振動板２２２の変形可能部２２２ａに所定のギャップ２２３を置いて対向する電極２２４とを含み、表面が略平坦面に形成されている。なお、アクチュエータ基板２０２の詳細な図示及び説明は省略するが、前記インクジェットヘッドの実施形態で説明したと同様である。
【０１０６】
このマイクロポンプの動作原理を説明すると、前述したインクジェットヘッドの場合と同様に、電極２２４に対して選択的にパルス電位を与えることによって振動板２２２との間で静電吸引力が生じるので、振動板２２２の変形可能部２２２ａが電極２２４側に変形する。ここで、振動板２２２の変形可能部２２２ａを図中右側から順次駆動することによって流路２０１内の流体は、矢印方向へ流れが生じ、流体の輸送が可能となる。
【０１０７】
この場合、本発明に係る静電型アクチュエータを備えることで、特性バラツキが少なく、安定した液体輸送を可能な小型で低消費電力のマイクロポンプを得られる。なお、ここでは振動板の変形可能部が複数ある例を示したが、変形可能部は１つでも良い。また、輸送効率を上げるために、変形可能部間に１又は複数の弁、例えば逆止弁などを設けることもできる。
【０１０８】
次に、本発明に係る静電型アクチュエータを備えた光学デバイスの一例について図１７を参照して説明する。なお、同図は同デバイスの概略構成図である。
この光学デバイスは、表面が光を反射可能でかつ変形可能なミラー３０１を含むアクチュエータ基板３０２を有している。ミラー３０１の表面は反射率を増加させるため誘電体多層膜や金属膜を形成する（これらは樹脂膜表面に形成する）と良い。
【０１０９】
アクチュエータ基板３０２は、ベース基板３２１上に設けた、変形可能なミラー３０１（ヘッドの振動板に相当する。）と、このミラー３０１の変形可能部３０１に所定のギャップ３２３を介して対向する電極３２４とを含む。このアクチュエータ基板３０２についても、振動板がミラー面を有する構成となっている点が前記インクジェットヘッドの実施形態で説明したものと異なるだけであるので、詳細な図示及び説明を省略する。
【０１１０】
この光学デバイスの原理を説明すると、前述したインクジェットヘッドの場合と同様に、電極３２４に対して選択的にパルス電位を与えることによって、電極３２４と対向するミラー３０１の変形可能部３０１ａ間で静電吸引力が生じるので、ミラー３０１の変形可能部３０１が凹状に変形して凹面ミラーとなる。したがって、光源３１０からの光がレンズ３１１を介してミラー３０１に照射した場合、ミラー３０１を駆動しないときには、光は入射角と同じ角度で反射するが、ミラー３０１を駆動した場合は駆動された変形可能部３０１が凹面ミラーとなるので反射光は発散光となる。これにより光変調デバイスが実現できる。
【０１１１】
そして、本発明に係る静電型アクチュエータを備えることで、特性バラツキの少ない小型で低消費電力の光学デバイスを得ることができる。
【０１１２】
そこで、この光学デバイスを応用した例を図１８をも参照して説明する。この例は、上述した光学デバイスを２次元に配列し、各ミラー３０１の変形可能部３０１ａを独立して駆動するようにしたものである。なお、ここでは、４×４の配列を示しているが、これ以上配列することも可能である。
【０１１３】
したがって、前述した図１７と同様に、光源３１０からの光はレンズ３１１を介してミラー３０１に照射され、ミラー３０１を駆動していないところに入射した光は、投影用レンズ３１２へ入射する。一方、電極３２４に電圧を印加してミラー３０１の変形可能部３０１ａを変形させている部分は凹面ミラーとなるので光は発散し投影用レンズ３１２にほとんど入射しない。この投影用レンズ３１２に入射した光はスクリーン（図示しない）などに投影され、スクリーンに画像を表示することができる。
【０１１４】
なお、上記実施形態においては、液滴吐出ヘッドとしてインクジェットヘッドに適用した例で説明したが、インクジェットヘッド以外の液滴吐出ヘッドとして、例えば、液体レジストを液滴として吐出する液滴吐出ヘッド、ＤＮＡの試料を液滴として吐出する液滴吐出ヘッドなどの他の液滴吐出ヘッドにも適用できる。また、静電型アクチュエータを備えるマイクロデバイスとして、マイクロポンプ、光学デバイス（光変調デバイス）、マイクロスイッチ（マイクロリレー）、マルチ光学レンズのアクチュエータ（光スイッチ）、マイクロ流量計、圧力センサなどにも適用することができる。また、前述したようにプリンタ、ファクシミリ、複写装置等の画像形成装置及び液滴を吐出する装置にも本発明に係る液滴吐出ヘッドを備えることができる。
【０１１５】
【発明の効果】
以上説明したように、本発明に係る静電型アクチュエータによれば、変形可能な振動板とこれに空隙を介して対向する電極とを備え、前記振動板を静電力で変形させる静電型アクチュエータにおいて、前記振動板と電極とは同一の基板に形成され、前記振動板には前記空隙に通じる除去孔を有し、前記除去孔内は封止材で封止され、前記封止材は前記空隙に入り込まない状態で前記除去孔内を封止している構成としたので、安定した動作特性が得られる。
【０１１６】
本発明に係る静電型アクチュエータの製造方法は、振動板の樹脂膜を成膜する膜の表面をフッ素化合物ガスに晒す構成とし、或いは振動板の樹脂膜を成膜する膜の表面に六弗化硫黄（ＳＦ_６）ガスでプラズマ処理を施す構成としたので、樹脂材料で犠牲層除去孔を封止する場合に、封止材が空隙に入り込まない状態で犠牲層除去孔を封止することができる。
【０１１７】
本発明に係る液滴吐出ヘッドによれば、液滴を吐出するノズルが連通する加圧液室内の液体を加圧するための本発明に係る静電型アクチュエータを備えている構成としたので、滴吐出特性のバラツキが少なく、安定した滴吐出を行うことができ、また低コスト化を図れ、信頼性が向上する。
【０１１８】
本発明に係るインクカートリッジによれば、本発明に係る液滴吐出ヘッドとこの液滴吐出ヘッドにインクを供給するインクタンクを一体化したので、滴吐出特性のバラツキが少なく、安定した滴吐出を行うことができ、また低コスト化を図れ、信頼性が向上する。
【０１１９】
本発明に係るインクジェット記録装置によれば、インク滴を吐出する本発明に係る液滴吐出ヘッド、または本発明に係るインクカートリッジを搭載したので、高画質記録が可能になる。本発明に係る画像形成装置によれば、本発明に係る液滴吐出ヘッドを備えているので、高画質記録が可能になる。また、本発明に係る液滴を吐出する装置によれば、本発明に係る液滴吐出ヘッドを備えているので、安定した液滴吐出を行うことができる。
【０１２０】
本発明に係るマイクロポンプによれば、流路の液体を加圧する本発明に係る静電型アクチュエータを構成するアクチュエータ基板と流路を形成する流路形成部材とを備えているので、小型で低消費電力のマイクロポンプが得られる。
【０１２１】
本発明に係る光学デバイスによれば、光を反射するミラーを変形させるための本発明に係る静電型アクチュエータを構成するアクチュエータ基板を備えているので、小型で低消費電力の光学デバイスが得られる。
【図面の簡単な説明】
【図１】本発明の液滴吐出ヘッドの第１実施形態に係るインクジェットヘッドの分解斜視図
【図２】同ヘッドのアクチュエータ基板の平面説明図
【図３】図２のＸ１−Ｘ１線に沿う断面説明図
【図４】図２のＸ２−Ｘ２線に沿う断面説明図
【図５】図２のＹ１−Ｙ１線に沿う断面説明図
【図６】図２のＹ２−Ｙ２線に沿う断面説明図
【図７】本発明に係る製造方法を含むインクジェットヘッドの製造工程の第１例の説明に供する断面説明図
【図８】図７に続く工程を説明する断面説明図
【図９】同じく第２例の説明に供する断面説明図
【図１０】図９に続く工程を説明する断面説明図
【図１１】同じく第３例の説明に供する断面説明図
【図１２】図１１に続く工程を説明する断面説明図
【図１３】本発明に係るインクカートリッジの説明に供する斜視説明図
【図１４】本発明に係るインクジェット記録装置の一例を説明する斜視説明図
【図１５】同記録装置の機構部の説明図
【図１６】本発明に係るマイクロポンプの一例を説明する説明図
【図１７】本発明に係る光学デバイスの一例を説明する説明図
【図１８】同光学デバイスを用いた光変調デバイスの一例を説明する斜視説明図
【符号の説明】
１…第１基板、２…第２基板（ノズル板）、４…ノズル孔、６…吐出室、７…流体抵抗部、８…共通液室、１１…アクチュエータ基板、１２…流路形成部材、２１…ベース基板、２２…振動板、２３…空隙、２４…電極、２８…樹脂膜、４１…犠牲層除去孔、１００…インクカートリッジ、１２４…記録ヘッド、２０１…流路基板、２０３…流路、２０２…アクチュエータ基板、２２２ａ…変形可能部、２４６…電極、３０１…ミラー、３０１ａ…変形可能部、３０２…アクチュエータ基板、３２４…電極。[0001]
[Industrial application fields]
  The present invention relates to an electrostatic actuator, a droplet discharge head and a manufacturing method thereof, an ink cartridge, an ink jet recording apparatus, a micro pump, and an optical device., Image forming apparatus, and apparatus for ejecting liquid dropletsAbout.
[0002]
[Prior art]
[Patent Document 1]
Japanese Patent Laid-Open No. 6-71882
[Patent Document 2]
JP 2001-18383 A
[Patent Document 3]
Republished patent WO99 / 34979
[0003]
An ink jet head, which is a liquid droplet ejection head used in an image recording apparatus such as a printer, a facsimile machine, a copying apparatus, or the like or an image forming apparatus, has a single or a plurality of nozzle holes for ejecting ink droplets, and the nozzle holes. A discharge chamber (also referred to as a pressurizing chamber, an ink chamber, a liquid chamber, a pressurized liquid chamber, a pressure chamber, an ink flow path, etc.) in communication with the pressure generating means for generating pressure for pressurizing ink in the discharging chamber The ink droplets are ejected from the nozzle holes by pressurizing the ink in the ejection chamber with the pressure generated by the pressure generating means.
[0004]
Examples of the droplet discharge head include a droplet discharge head that discharges a liquid resist as a droplet, and a droplet discharge head that discharges a DNA sample as a droplet. The following description will focus on an inkjet head. . In addition, the microactuator constituting the actuator of the droplet discharge head is, for example, an optical device such as a micropump or a micro light modulation device, a micro switch (micro relay), an actuator (optical switch) of a multi optical lens, a micro flow meter, a pressure It can also be applied to sensors and the like.
[0005]
By the way, as a droplet discharge head, a piezoelectric type that discharges ink droplets by deforming and displacing a vibration plate forming a wall surface of a discharge chamber using an electromechanical conversion element such as a piezoelectric element as pressure generating means. A thermal type that generates bubbles by ink film boiling and discharges ink droplets using an electrothermal transducer such as a heating resistor disposed in the discharge chamber, and a vibration plate that forms the wall surface of the discharge chamber There are electrostatic types that eject ink droplets by being deformed by electric power.
[0006]
In recent years, bubble-type and electrostatic types that are lead-free have attracted attention due to environmental problems, and in addition to lead-free, a plurality of electrostatic types that have little influence on the environment from the viewpoint of low power consumption have been proposed.
[0007]
As this electrostatic type ink jet head, for example, as described in [Patent Document 1], a pair of electrodes is provided via an air gap, and one electrode functions as a diaphragm, and the diaphragm An ink chamber filled with ink is formed on the opposite side of the opposite electrode, and electrostatic attraction works between the electrodes by applying a voltage between the electrodes (between the vibration plate and the electrode). When the voltage is removed by deformation, the diaphragm returns to its original state by an elastic force, and ink droplets are ejected using the force.
[0008]
In such an electrostatic ink jet head, the distance between the diaphragm and the electrode, that is, the dimensional accuracy of the air gap greatly affects the performance. In particular, in the case of an ink jet head, if the variation in the characteristics of each actuator is large, the printing accuracy and the reproducibility of the image quality will be significantly reduced. In order to reduce the voltage, the gap interval is about 0.2 to 2.0 μm, and more dimensional accuracy is required.
[0009]
Therefore, in [Patent Document 2] or [Patent Document 3], a minute gap between the diaphragm and the electrode is formed by applying a sacrificial layer process (by sacrificial layer etching), and a flow path substrate is formed thereon. It is disclosed that a head is formed by bonding. According to this method, the gap dimension is almost determined only by the variation in the sacrificial layer film forming process, so that the variation in dimension can be suppressed and a highly accurate and reliable actuator or head can be obtained.
[0010]
[Problems to be solved by the invention]
As described above, when the void is formed by the sacrificial layer process, it is necessary to seal the sacrificial layer removal hole for removing the sacrificial layer. Therefore, [Patent Document 3] discloses that the sacrificial layer hole after the sacrificial layer removal is closed with Ni, SiO2 or the like using a PVD method or a CVD method using a vacuum apparatus. When sealing is performed by such a film forming method, the film forming component may enter the gap. The sacrificial layer removal hole also serves to ensure the strength of the partition wall and cannot be made very small, so it is not suitable for high density. From these facts, it is considered that the operating characteristics and reliability of the actuator are adversely affected and it is impossible to cope with higher density.
[0011]
Also,
In the head described in Patent Document 2, there is a difference in the structure between the partition wall and the diaphragm, and high accuracy is required for joining the flow path substrates, and the thin diaphragm removes the sacrificial layer. Since it floats from the surroundings in stages, it may be damaged in the subsequent process, and it is difficult to manufacture with a high yield.
[0012]
In addition, the sacrificial layer removal hole is sealed with a film formed by a film forming method using a vacuum device. However, in the case of film formation with a vacuum device, the gap is vacuum sealed because the process is in a vacuum. It will be. Therefore, when exposed to the atmosphere, the pressure in the air gap is negative, and the diaphragm bends, causing a problem that the desired amount of displacement cannot be obtained. If there is a variation in the deflection, a variation in the displacement occurs. In addition, since there is no gas damper effect in the gap in the vacuum sealing, the variation in vibration displacement with respect to the variation in diaphragm thickness increases. In order to solve such a problem, a structure or process that opens to the atmosphere is required, which causes an increase in cost, a decrease in yield, and the like.
[0013]
As described above, in the actuator and head to which the conventional sacrificial layer process is applied, there is a problem that it is difficult to obtain an actuator using an electrostatic force that is inexpensive, highly accurate, and highly reliable.
[0014]
  The present invention has been made in view of the above problems, and an electrostatic actuator capable of obtaining stable operation characteristics, a droplet ejection head capable of obtaining stable droplet ejection characteristics and high-quality recording, and the droplets Ink cartridge with integrated discharge head, ink jet recording apparatus equipped with this droplet discharge head or ink cartridge, micropump using this actuator, and optical device, Image forming apparatus equipped with the liquid droplet ejection head, and apparatus for ejecting liquid dropletsThe purpose is to provide.
[0015]
  In order to solve the above-described problems, an electrostatic actuator according to the present invention includes a deformable diaphragm and an electrode facing the diaphragm through a gap, and deforms the diaphragm with an electrostatic force. The diaphragm and the electrode are formed on the same substrate, and the diaphragm communicates with the gap.HoleBefore andHoleThe inside is sealed with a sealant, and the sealant does not enter the gap beforeHoleIt was set as the structure which sealed the inside.
[0016]
  here,The planar shape of the hole is a polygon, circle, or ellipse, and its cross-sectional area is 10 μm.²The following is preferable. Also,The thickness of the hole is preferably 0.1 μm or more.
[0017]
Further, the sealing material is preferably a part of the film constituting the diaphragm. In this case, the film constituting the diaphragm is preferably a resin film that can be formed in the atmosphere, and the resin film is a polybenzoxoxalate. Dole (PBO) membranes are preferred. Furthermore, it is preferable that the surface of the film for forming the resin film of the diaphragm contains fluorine, or the surface of the film for forming the resin film of the diaphragm is preferably subjected to plasma treatment.
[0018]
The manufacturing method of the electrostatic actuator according to the present invention is configured such that the surface of the film for forming the resin film of the diaphragm is exposed to the fluorine compound gas. In this case, xenon difluoride (XeF) is used as the fluorine compound gas.₂It is preferable to use a gas.
[0019]
Also, in the method for manufacturing an electrostatic actuator according to the present invention, sulfur hexafluoride (SF) is formed on the surface of the film for forming the resin film of the diaphragm.₆) A structure in which plasma treatment is performed with gas.
[0020]
The droplet discharge head according to the present invention includes the electrostatic actuator according to the present invention for pressurizing a liquid in a pressurized liquid chamber to which a nozzle for discharging a droplet communicates.
[0021]
The ink cartridge according to the present invention is obtained by integrating the droplet discharge head according to the present invention and an ink tank that supplies ink to the droplet discharge head.
[0022]
  An ink jet recording apparatus according to the present invention is equipped with a liquid droplet ejection head according to the present invention for ejecting ink droplets or an ink cartridge according to the present invention.An image forming apparatus and an apparatus for ejecting liquid droplets according to the present invention include the liquid droplet ejection head according to the present invention.It is a configuration.
[0023]
The micropump according to the present invention includes the electrostatic actuator according to the present invention that pressurizes the liquid in the flow path.
[0024]
An optical device according to the present invention includes an electrostatic actuator according to the present invention for deforming a mirror that reflects light.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is an exploded perspective view of an ink jet head as a droplet discharge head according to the present invention, and is a partial cross-sectional view. 2 is an explanatory plan view of the actuator substrate of the head, FIG. 3 is an explanatory sectional view taken along line X1-X1 in FIG. 2, FIG. 4 is an explanatory sectional view taken along line X2-X2 in FIG. FIG. 6 is a cross-sectional explanatory view taken along line Y1, and FIG. 6 is a cross-sectional explanatory view taken along line Y2-Y2 in FIG.
[0026]
This ink jet head is of a side shooter type in which ink droplets are ejected from nozzle holes provided on the surface of the substrate, and has a laminated structure in which two first and second substrates 1 and 2 are stacked and joined. In addition, by joining the first substrate 1 and the second substrate 2, ink is supplied to the discharge chamber 6 through which the plurality of nozzle holes 4 for discharging ink droplets communicate with each other and the discharge chamber 6 through the fluid resistance portion 7. A flow path such as a common liquid chamber (common ink chamber) 8 is formed. Note that an edge shooter type in which ink droplets are ejected from nozzle holes provided at the end of the substrate can also be used.
[0027]
The first substrate 1 is obtained by joining a flow path forming member 12 that forms flow paths such as a discharge chamber 6 and a common liquid chamber 8 on an actuator substrate 11 constituting an electrostatic actuator according to the present invention.
[0028]
The actuator substrate 11 has a deformable diaphragm 22 on a base substrate 21 made of a single crystal silicon substrate, and an electrode (lower electrode) 24 facing the diaphragm 22 via a gap (gap) 23. Yes.
[0029]
Here, the electrode 24 is formed on the insulating film 25 formed on the base substrate 21 and separated by a separation groove for each channel, and this separation groove is an insulation formed on the surface of the electrode 24 (surface on the diaphragm 22 side). The film 27 is embedded. Note that the material for forming the electrode 24 (referred to as an electrode material or an electrode member) is also left as the partition wall portion 26.
[0030]
Polysilicon or compound silicide can be used as the material (electrode member) of the electrode 24, and these materials can be formed and processed with stable quality and can withstand a high temperature process. In other processes, the temperature restriction is reduced, and a highly reliable insulating film (HTO film), for example, can be stacked as the insulating film 27, so that the range of process selection can be expanded and the cost can be reduced. And high reliability.
[0031]
In addition, a metal or a refractory metal can be used as the material (electrode member) of the electrode 24. This makes it possible to greatly reduce the resistance, reduce the driving voltage, and stabilize any material. Since film formation and processing can be performed with the improved quality, cost reduction and high reliability can be achieved.
[0032]
The gap 23 was formed by etching away a sacrificial layer formed between the diaphragm 22 and the electrode 24 as described later (formed by applying a sacrificial layer process), and was used for forming the gap. Of the sacrificial layer, at least the sacrificial layer between the plurality of voids 23 is left to form the partition wall 28.
[0033]
In this way, by forming the gap 23 by sacrificial layer etching, the gap interval (gap length) can be precisely defined by the thickness of the sacrificial layer, so that variation is reduced and foreign matter or the like enters the gap. This can be prevented and the yield is improved. Further, since the sacrificial layer is also left in the portion that becomes the partition wall portion 28, the surface of the actuator substrate 11 can be formed more flatly without forming a gap step, and for example, an ink-wetted film can be formed or flown. The process design of the subsequent process such as the joining process of the path forming member 12 becomes easy, and the cost can be reduced and the reliability can be improved.
[0034]
Here, it is preferable to use polysilicon or amorphous silicon as the sacrificial layer. These materials can be removed by etching, and by forming silicon oxide films with high etching selectivity on the top and bottom of the sacrificial layer, a manufacturing process with little variation can be achieved, and mass production can be performed at low cost. Is possible.
[0035]
Moreover, the diaphragm region 31 forming the diaphragm 22 is separated from the partition wall 33 by the separation groove 32 as shown in FIG. The separation groove 32 is formed so that no step is generated between the partition wall 33 and the diaphragm region 31. The short side length and the long side length of the diaphragm region 31 are, for example, short side length a: 120 μm and long side length b: 800 μm.
[0036]
The diaphragm 22 includes an insulating film (protective film) 35, an upper electrode film 36, a film deflection preventing film 37, and a resin film 38 from the electrode side (lower layer). A part of the insulating film 35 also serves as a protective film for leaving the sacrificial layer on the gap interval wall portion 28. The insulating film 35 on the wall surface of the partition wall 28 is filled with a separation groove formed in the sacrificial layer in the manufacturing process. The electrode material forming the electrode film 36 is separated into the electrode film 36 and the partition wall 39.
[0037]
As shown in FIG. 2, a sacrificial layer removal hole 41 for removing the sacrificial layer is formed in the protective film 35 of the diaphragm 22, and an opening larger than the sacrificial layer removal hole 41 is formed in the upper electrode film 36. A portion 42 is formed. The sacrificial layer removal holes 41 are arranged at equal intervals in the long side length at intervals equal to or shorter than the short side length of the diaphragm region 31, and the sacrificial layer removal holes 41 are formed at the same positions on the opposite sides. Thus, by arranging a plurality of sacrifice layer removal holes 41, the sacrifice layer can be etched efficiently and the gap 23 can be formed.
[0038]
The sacrificial layer removal hole 41 is sealed with a part of a resin film 38 (referred to as a sealing portion 38 a) that is a film constituting the vibration plate 22. That is, the sealing material) seals the sacrificial layer removal hole 41 in a state where it does not enter the gap 23. In this way, by sealing the sacrificial layer removal hole with a part of the film constituting the diaphragm, the step of only sealing becomes unnecessary, the number of steps can be reduced, and the cost can be reduced.
[0039]
In addition, since the sacrificial layer removal hole 41 is sealed using a resin material (resin film) as a film constituting the diaphragm 22, sealing can be performed in the atmosphere, so that the gap is large even after sealing. It can be kept at atmospheric pressure. Accordingly, it is possible to prevent a situation in which a desired amount of vibration plate displacement cannot be obtained due to the negative pressure but there is no gap 23 as in the case of sealing in a vacuum, and variation in vibration plate displacement is prevented.
[0040]
Here, the arrangement and size of the sacrificial layer removal hole 41 will be described.
In the case of an ink jet head, the actuator for ejecting ink droplets is an elongated rectangle, and the adjacent actuators are generally arranged on the long side with the partition wall 33 interposed therebetween. Since the sacrificial layer etching is isotropic, the sacrificial layer removal efficiency becomes higher when the sacrificial layer removal hole 41 is arranged in the center of the sacrificial layer. However, since the sacrificial layer removal hole 41 in the displacement region of the diaphragm may affect the vibration characteristics of the actuator, the sacrificial layer removal hole 41 is preferably disposed at the long side end of the diaphragm. However, the sacrificial layer removal hole 41 is preferably disposed outside the vibration region in order to avoid an influence on the vibration plate displacement.
[0041]
Further, the size of the sacrificial layer removal hole 41 is preferably larger from the viewpoint of sacrificial layer etching. However, when the sacrificial layer removal hole 41 is disposed on the long side of the diaphragm, the influence on the vibration plate displacement region, From the viewpoint of securing the strength of the partition wall 33 and sealing the sacrificial layer removal hole by the resin film, the smaller one is preferable. It is necessary to determine the size of the sacrificial layer removal hole 41 that satisfies these conflicting conditions. However, since the sacrificial layer can be easily removed by arranging a plurality of sacrificial layer removing holes 41 in multiple rows, the size of the sacrificial layer removing hole 41 is determined by the sacrificial layer removing hole sealing property. .
[0042]
In order to seal the sacrificial layer removal hole 41 with the resin film 38 as in the present embodiment, the sacrificial layer removal hole 41 has a cross-sectional area of 10 μm as viewed from the diaphragm plane.²The following is preferable. Thus, the sectional area of the sacrificial layer removal hole 41 as viewed from the plane of the diaphragm is 10 μm.²By making the following, the resin material is reliably prevented from entering the gap 23 in sealing the sacrificial layer removal hole 41 with the resin material.
[0043]
Further, in this way, the sacrificial layer removal hole 41 has a cross-sectional area of 10 μm.²By ensuring that the sealing performance is determined by the cross-sectional area regardless of the planar shape of the sacrificial layer removal hole, the planar shape of the sacrificial layer removal hole can be polygonal, circular, or elliptical. Sufficient design freedom for surfaces and components can be secured.
[0044]
In addition, the thickness of the insulating film 35 that is the thickness of the sacrificial layer removal hole 41 is preferably 0.1 μm or more. If the thickness of the diaphragm constituting film in which the sacrificial layer removal hole is opened is thinner than 0.1 μm, the strength of this part is not sufficient, and the periphery of the sacrificial layer removal hole is destroyed by the impact when the resin material is applied. There is a risk that the film may penetrate into the voids. By setting the thickness of the constituent film to 0.1 μm or more, sealing is possible without destroying the periphery of the sacrificial layer removal hole when the resin material is applied, and the yield of the manufacturing process is improved.
[0045]
Polysilicon or compound silicide can be used as the material of the electrode film (upper electrode) 36 constituting a part of the diaphragm 22, and these materials can be formed and processed with stable quality. The structure can withstand high temperature processes.
[0046]
In addition, as the material of the electrode film 36 constituting a part of the diaphragm 22, a metal or a refractory metal can be used, which can significantly reduce resistance and drive voltage. In addition, since any material can be formed and processed with stable quality, cost reduction and high reliability can be achieved.
[0047]
The actuator substrate 11 configured as described above has a substantially flat surface on the vibration plate 22 side. As described above, since the surface of the actuator substrate 11 on the vibration plate 22 side is formed to be substantially flat, it becomes easy to join and form the flow path forming member. The mold actuator can be manufactured at low cost.
[0048]
The flow path forming member 12 is formed by bonding the surface of the actuator substrate 11 that is a substantially flat surface to the vibration plate 22 side and etching away a portion corresponding to the discharge chamber 6 and the like.
[0049]
The second substrate 2 bonded to the upper surface of the flow path forming member 12 of the first substrate 1 is a nickel substrate having a thickness of 50 microns, and the nozzle hole is formed in the surface portion of the substrate 2 so as to communicate with the discharge chamber 6. 4. A groove 7 serving as a fluid resistance is provided for communicating the common liquid chamber 8 and the discharge chamber 6, and an ink supply port 9 is provided so as to communicate with the common liquid chamber 8.
[0050]
The operation of the ink jet head configured as described above will be described. When a pulse potential of 40 V is applied from the oscillation circuit (drive circuit) to the electrode (lower electrode) 24 in a state where the discharge chamber 6 is filled with ink, the surface of the electrode 24 is charged to a positive potential, and the upper electrode of the diaphragm 22 is charged. An electrostatic force acts between the membrane 36 and the diaphragm 22 is bent toward the individual electrode 24 side. As a result, the pressure in the discharge chamber 6 decreases, and ink flows into the discharge chamber 6 from the common liquid chamber 8 via the fluid resistance portion 7.
[0051]
Thereafter, when the pulse voltage to the electrode 24 is set to 0 V, the diaphragm 22 bent downward by electrostatic force returns to its original state due to its own rigidity. As a result, the pressure in the discharge chamber 6 rapidly increases and ink droplets are discharged from the nozzle holes 4. By repeating this, ink droplets can be ejected continuously.
[0052]
Here, the force F acting between the upper electrode film 36 and the lower electrode 24 of the diaphragm 22 as an electrode increases in inverse proportion to the square of the inter-electrode distance d as shown in the following equation (1). . In order to drive at a low voltage, it is important to narrow the gap (gap length) between the gap (gap) 23 between the electrode 24 and the diaphragm 22.
[0053]
[Expression 1]

[0054]
In the equation (1), F: force acting between electrodes, ε: dielectric constant, S: area of opposing surfaces of electrodes, d: distance between electrodes, V: applied voltage.
[0055]
Therefore, by forming the gap 23 by sacrificial layer etching as described above, a minute gap can be formed with high accuracy. Then, by sealing the sacrificial layer removal hole for removing the sacrificial layer by this sacrificial layer etching in a state where the sealing material does not enter the gap, the characteristic variation of the actuator is reduced and stable operation characteristics can be obtained. As a result, stable droplet ejection characteristics can be obtained.
[0056]
Furthermore, the sacrificial layer removal hole formed in the diaphragm for forming the gap is sealed with the material constituting the actuator, so that the entry of foreign matter and contaminants into the gap can be prevented in the manufacturing process. A highly reliable actuator can be obtained.
[0057]
As a result, it is possible to obtain a liquid droplet ejection head or actuator that is highly accurate and highly reliable without any variation in performance at a low cost.
[0058]
Next, a first example of the manufacturing process of the inkjet head in which the manufacturing method according to the present invention is performed will be described with reference to FIGS. In addition, both figures are sectional explanatory drawings with which it uses for description of the manufacturing process of the actuator board | substrate of the head.
First, as shown in FIG. 7A, an insulating film (thermal oxide film) 25 is formed to a thickness of 1.6 μm on a Si substrate 21 which is a base substrate having a thickness of 400 μm. Then, a P-doped polysilicon film having a thickness of 0.4 μm is formed as a lower electrode material, and a separation groove is formed by a lithoetch method to separate the electrode 24 and the partition wall portion 26.
[0059]
Thereafter, a protective film 27 which is a CVD oxide film is deposited on the electrode 24 and the partition wall 26 by 0.2 μm. The protective film 27 serves as a mask material that protects the electrode 24 in the sacrificial layer process, and also functions as a protective film that prevents a short circuit between the electrode 24 and the electrode film 36 constituting the diaphragm 22.
[0060]
Next, as shown in FIG. 5B, a sacrificial layer (non-doped polysilicon) is formed by a CVD method with a thickness of 0.2 μm as a gap interval, and a region that forms the gap 23 and a partition wall portion 28 by a lithoetch method. It separates into the area which becomes. In the case where the partition wall portion 26 is used as the wiring layer of the electrode 24, only the partition wall portion 28 is opened by resist patterning using a lithography method and the resistance is reduced using ion implantation and densification methods.
[0061]
Thereafter, a protective film (CVD oxide film) 35 is deposited to a thickness of 0.1 μm. The protective film 35 serves as a mask material that protects the electrode film 36 that constitutes the diaphragm 22 in the sacrificial layer process, and also functions as a protective film that prevents a short circuit between the electrode 24 and the electrode film 36.
[0062]
Next, as shown in FIG. 3C, P-doped polysilicon is deposited as an electrode material to a thickness of 0.2 μm and separated into a region to be the electrode film 36 and a region to be the partition wall 39 by a lithoetch method. At the same time, the protective hole (opening) 42 is opened larger than the sacrifice layer removal hole 41 so that the electrode film 36 made of the same material as the sacrifice layer is not etched when the sacrifice layer is removed. Then, a nitride film as a deflection preventing film 37 constituting the diaphragm 22 is deposited on the electrode film 36 to a thickness of 0.2 μm by the CVD method.
[0063]
Thereafter, as shown in FIG. 8A, sacrificial layer removal holes 41 are formed in the nitride film (deflection prevention film) 37 and the insulating film 35 by a lithoetch method. After removing the resist, as shown in FIG. 4B, a processing method with high etch rate selectivity for the sacrificial layer 51, the nitride film (anti-bending film) 37, and the insulating film 35, for example, SF₆Isotropic dry etching method or XeF₂The sacrificial layer 51 is completely removed by a dry etching method to form the gap 23.
[0064]
Then, as shown in FIG. 2C, a PBO film (polybenzoxazole) as a resin film 38 to be a liquid contact film is formed with a thickness of 1 μm by spin coating. At this time, the sacrificial layer removal hole 41 is completely sealed with the PBO film (resin film) 38. Thereafter, only the electrode wiring extraction pad portion is opened by the lithoetch method.
[0065]
Thus, the actuator substrate 11 is completed, and the flow path plate 12 and the nozzle plate 2 are joined to the actuator substrate 11 to complete the droplet discharge head.
[0066]
In addition, although the PBO film | membrane was mentioned as an example as a resin film (here it becomes a liquid contact film | membrane), the film | membrane which is corrosion-resistant with respect to an ink and can seal a sacrifice layer removal hole, for example, a polyimide film Etc.
[0067]
Since a resin film such as a PBO film can seal the sacrificial layer removal hole 41 in the air, the air gap is vacuum-sealed like a film formed by a PVD method or a CVD method using a vacuum apparatus, and is exposed to the atmosphere. By doing so, there is no problem that the inside of the air gap becomes negative pressure and the diaphragm bends and the desired amount of displacement cannot be obtained.
[0068]
Next, a second example of the manufacturing process of the ink jet head will be described with reference to FIGS. In addition, both figures are sectional explanatory drawings with which it uses for description of the manufacturing process of the actuator board | substrate of the head.
First, the steps shown in FIGS. 9A to 9C are the same as the steps shown in FIGS. 7A to 7C of the first example. That is, as shown in FIG. 9A, an insulating film (thermal oxide film) 25 is formed to a thickness of 1.6 μm on a Si substrate 21 which is a base substrate having a thickness of 400 μm. Then, a P-doped polysilicon film having a thickness of 0.4 μm is formed as a lower electrode material, and a separation groove is formed by a lithoetch method to separate the electrode 24 and the partition wall portion 26.
[0069]
Thereafter, a protective film 27 which is a CVD oxide film is deposited on the electrode 24 and the partition wall 26 by 0.2 μm. The protective film 27 serves as a mask material that protects the electrode 24 in the sacrificial layer process, and also functions as a protective film that prevents a short circuit between the electrode 24 and the electrode film 36 constituting the diaphragm 22.
[0070]
Next, as shown in FIG. 5B, a sacrificial layer (non-doped polysilicon) is formed by a CVD method with a thickness of 0.2 μm as a gap interval, and a region that forms the gap 23 and a partition wall portion 28 by a lithoetch method. It separates into the area which becomes. In the case where the partition wall portion 26 is used as the wiring layer of the electrode 24, only the partition wall portion 28 is opened by resist patterning using a lithography method and the resistance is reduced using ion implantation and densification methods.
[0071]
Thereafter, a protective film (CVD oxide film) 35 is deposited to a thickness of 0.1 μm. The protective film 35 serves as a mask material that protects the electrode film 36 that constitutes the diaphragm 22 in the sacrificial layer process, and also functions as a protective film that prevents a short circuit between the electrode 24 and the electrode film 36.
[0072]
Next, as shown in FIG. 3C, P-doped polysilicon is deposited as an electrode material to a thickness of 0.2 μm and separated into a region to be the electrode film 36 and a region to be the partition wall 39 by a lithoetch method. At the same time, the protective hole (opening) 42 is opened larger than the sacrifice layer removal hole 41 so that the electrode film 36 made of the same material as the sacrifice layer is not etched when the sacrifice layer is removed. Then, a nitride film as a deflection preventing film 37 constituting the diaphragm 22 is deposited on the electrode film 36 to a thickness of 0.2 μm by the CVD method.
[0073]
Thereafter, as shown in FIG. 10A, a mask is formed with a resist 52, and a sacrificial layer removal hole 41 is formed in the nitride film (anti-bending film) 37 and the insulating film 35 by a litho-etch method. Then, without removing the resist 52, as shown in FIG. 5B, a processing method with high etch rate selectivity of the sacrificial layer 51, the nitride film (deflection prevention film) 37, and the insulating film 35, for example, SF₆Isotropic dry etching method or XeF₂The sacrificial layer 51 is completely removed by a dry etching method to form the gap 23.
[0074]
Then, as shown in FIG. 3C, after removing the resist 52, a PBO film (polybenzoxazole) as the resin film 38 is applied. At this time, there is a possibility that the PBO film (resin film) 38 may enter the gap 23 from the sacrificial layer removal hole 41. Therefore, before forming the PBO film (resin film) 38, the nitride film (deflection prevention film) 37 Modify the surface.
[0075]
The modification of the surface of the anti-bending film 37 that is the film forming the resin film 38 is, for example, SF₆This is done by exposure to plasma. Thereby, the wettability with respect to the PBO film 38 is reduced, and the PBO film (resin film) 38 is prevented from entering the gap 23 from the sacrificial layer removal hole 41, and the sacrificial layer removal hole 41 enters the gap 23. It can seal without.
[0076]
Thus, the actuator substrate 11 is completed, and the flow path plate 12 and the nozzle plate 2 are joined to the actuator substrate 11 to complete the droplet discharge head.
[0077]
In both the first example and the second example, the coating surface when the PBO film that is the resin film 38 is applied is a nitride film that is the deflection preventing film 37. When this nitride film is exposed to oxygen plasma at the time of resist removal, the wettability with the PBO film 38 is improved, and the PBO film 38 tends to penetrate into the gap 23 from the sacrificial layer removal hole 41.
[0078]
Therefore, the surface of the nitride film, that is, the surface of the film forming the resin film is made SF.₆By exposing to fluorine-containing plasma such as, the wettability with the PBO film 38 is reduced, and the penetration of the PBO film 38 into the voids 23 can be prevented. In this case, in the first example, SF is removed when the sacrificial layer is removed.₆The sacrificial layer removal and the surface modification are performed at the same time by exposing to a gas such as. In the second example, the surface modification treatment is performed after removing the resist.
[0079]
In any case, fluorine is contained on the surface of the film forming the resin film, so that the wettability with the resin film is lowered, the sealing margin of the sacrifice layer removal hole is improved, the yield is improved, and the quality is improved. To do. And in order to make the film | membrane surface which forms a resin film contain a fluorine in this way, it can carry out by using the fluorine compound gas and apparatus generally used by semiconductor manufacture, and is special. An apparatus is not necessary, and it can be handled by existing equipment, so that stable surface modification treatment is possible.
[0080]
In addition, as a means for reducing wettability with the PBO film, there is a method of exposing to a xenon difluoride gas atmosphere. In this case, since it is only exposed to a gas atmosphere, an expensive apparatus such as plasma processing is not required, and there is an advantage that surface modification processing can be performed.
[0081]
Further, in the first example, the nitride film (anti-bending film) 37 that is the surface of the diaphragm is exposed during the sacrifice layer etching for forming the gap 23, so that the etching is performed around 100 nm in consideration of the etching. It is necessary to set the thickness of the nitride film. Further, since the film thickness variation of the nitride film occurs at the time of sacrificial layer etching, it may be disadvantageous for forming the actuator with high accuracy.
[0082]
On the other hand, in the second example, the surface of the diaphragm when the sacrificial layer is removed is protected by the resist 52, and the nitride film is hardly etched in the surface treatment after removing the resist. The actuator can be formed with higher accuracy than the example.
[0083]
Next, a third example of the manufacturing process of the inkjet head will be described with reference to FIGS. In addition, both figures are sectional explanatory drawings with which it uses for description of the manufacturing process of the actuator board | substrate of the head.
First, the steps shown in FIGS. 11A and 11B are the same as the steps shown in FIGS. 7A to 7C of the first example. That is, as shown in FIG. 11A, an insulating film (thermal oxide film) 25 is formed to a thickness of 1.6 μm on a Si substrate 21 which is a base substrate having a thickness of 400 μm. Then, a P-doped polysilicon film having a thickness of 0.4 μm is formed as a lower electrode material, and a separation groove is formed by a lithoetch method to separate the electrode 24 and the partition wall portion 26.
[0084]
Thereafter, a protective film 27 which is a CVD oxide film is deposited on the electrode 24 and the partition wall 26 by 0.2 μm. The protective film 27 serves as a mask material that protects the electrode 24 in the sacrificial layer process, and also functions as a protective film that prevents a short circuit between the electrode 24 and the electrode film 36 constituting the diaphragm 22.
[0085]
Next, as shown in FIG. 5B, a sacrificial layer (non-doped polysilicon) is formed by a CVD method with a thickness of 0.2 μm as a gap interval, and a region that forms the gap 23 and a partition wall portion 28 by a lithoetch method. It separates into the area which becomes. In the case where the partition wall portion 26 is used as the wiring layer of the electrode 24, only the partition wall portion 28 is opened by resist patterning using a lithography method and the resistance is reduced using ion implantation and densification methods.
[0086]
Thereafter, a protective film (CVD oxide film) 35 is deposited to a thickness of 0.1 μm. The protective film 35 serves as a mask material that protects the electrode film 36 that constitutes the diaphragm 22 in the sacrificial layer process, and also functions as a protective film that prevents a short circuit between the electrode 24 and the electrode film 36.
[0087]
Next, as shown in FIG. 3C, P-doped polysilicon is deposited as an electrode material to a thickness of 0.2 μm and separated into a region to be the electrode film 36 and a region to be the partition wall 39 by a lithoetch method. At the same time, the protective hole (opening) 42 is opened larger than the sacrifice layer removal hole 41 so that the electrode film 36 made of the same material as the sacrifice layer is not etched when the sacrifice layer is removed. Then, a nitride film as a deflection preventing film 37 constituting the diaphragm 22 is deposited on the electrode film 36 to a thickness of 0.2 μm by the CVD method. Further, a protective film (CVD oxide film) 53 is deposited on the nitride film (deflection prevention film) 37 to a thickness of 0.05 μm.
[0088]
After that, as shown in FIG. 12A, a mask is formed with a resist 52, and a sacrificial layer removal hole 41 is formed in the nitride film (anti-bending film) 37 and the insulating film 35 by a litho-etch method. Then, without removing the resist 52, as shown in FIG. 5B, a processing method with high etch rate selectivity of the sacrificial layer 51, the nitride film (deflection prevention film) 37, and the insulating film 35, for example, SF₆Isotropic dry etching method or XeF₂The sacrificial layer 51 is completely removed by a dry etching method to form the gap 23.
[0089]
Then, as shown in FIG. 3C, after removing the resist 52, a PBO film (polybenzoxazole) as the resin film 38 is applied. The PBO film 38 does not penetrate into the gap 23 from the sacrificial layer removal hole 41 and seals the sacrificial layer removal hole 41.
[0090]
In this third example, the surface on which the PBO film 38 is applied is a CVD oxide film 53. Unlike the nitride films of the first and second examples, the PBO film 38 has the voids 23 without performing surface modification treatment. It does not penetrate inside and does not require a surface modification step.
[0091]
Next, an ink cartridge according to the present invention will be described with reference to FIG.
The ink cartridge 100 includes an ink jet head 102 that is a droplet discharge head according to the present invention having nozzle holes 101 and the like, and an ink tank 103 that supplies ink to the ink jet head 101.
[0092]
By integrating the ink tank that supplies ink to the droplet discharge head according to the present invention as described above, an ink cartridge (ink tank) that integrates a highly reliable droplet discharge head with little variation in droplet discharge characteristics. Integrated head) can be obtained at low cost.
[0093]
  Next, an ink jet head which is a droplet discharge head according to the present invention is mounted.As an image forming apparatus including an apparatus for discharging droplets according to the present inventionAn example of the mechanism of the ink jet recording apparatus will be described with reference to FIGS. 14 is an explanatory perspective view of the recording apparatus, and FIG. 15 is an explanatory side view of a mechanism portion of the recording apparatus.
[0094]
This ink jet recording apparatus includes a carriage movable in the main scanning direction inside the recording apparatus main body 111, a recording head comprising the ink jet head according to the present invention mounted on the carriage, an ink cartridge for supplying ink to the recording head, and the like. A paper feed cassette (or a paper feed tray) 114 on which a large number of sheets 113 can be stacked from the front side is detachably attached to the lower part of the apparatus main body 111. In addition, the manual feed tray 115 for manually feeding the paper 113 can be opened, the paper 113 fed from the paper feed cassette 114 or the manual feed tray 115 is taken in, and the printing mechanism unit 112 takes the required After the image is recorded, it is discharged to a discharge tray 116 mounted on the rear side.
[0095]
The printing mechanism 112 holds a carriage 123 slidably in the main scanning direction by a main guide rod 121 and a sub guide rod 122 which are guide members horizontally mounted on left and right side plates (not shown). (Y), cyan (C), magenta (M), black (Bk) each head is composed of an ink jet head that is a liquid droplet ejection head according to the present invention for ejecting ink droplets of each color, and a plurality of ink ejection openings are mainly used. They are arranged in a direction crossing the scanning direction and mounted with the ink droplet ejection direction facing downward. Also, each ink cartridge 125 for supplying each color ink to the head 124 is replaceably mounted on the carriage 123. Note that the ink cartridge 100 according to the present invention may be mounted.
[0096]
The ink cartridge 125 has an air port that communicates with the atmosphere upward, a supply port that supplies ink to the inkjet head below, and a porous body filled with ink inside, and the capillary force of the porous body Thus, the ink supplied to the inkjet head is maintained at a slight negative pressure.
[0097]
Further, although the heads 124 of the respective colors are used here as the recording heads, a single head having nozzles for ejecting ink droplets of the respective colors may be used.
[0098]
Here, the carriage 123 is slidably fitted to the main guide rod 121 on the rear side (downstream side in the paper conveyance direction), and is slidably mounted on the sub guide rod 122 on the front side (upstream side in the paper conveyance direction). is doing. In order to move and scan the carriage 123 in the main scanning direction, a timing belt 130 is stretched between a driving pulley 128 and a driven pulley 129 that are rotationally driven by a main scanning motor 127. The carriage 123 is reciprocally driven by forward and reverse rotation of the main scanning motor 127.
[0099]
On the other hand, in order to convey the sheet 113 set in the sheet cassette 114 to the lower side of the head 124, the sheet 113 is guided from the sheet feeding cassette 114 to the sheet feeding roller 131 and the friction pad 132. A guide member 133, a transport roller 134 that reverses and transports the fed paper 113, a transport roller 135 that is pressed against the peripheral surface of the transport roller 134, and a tip that defines the feed angle of the paper 113 from the transport roller 134 A roller 136 is provided. The transport roller 134 is rotationally driven by a sub-scanning motor 137 through a gear train.
[0100]
A printing receiving member 139 is provided as a paper guide member that guides the paper 113 fed from the transport roller 134 on the lower side of the recording head 124 corresponding to the movement range of the carriage 123 in the main scanning direction. On the downstream side of the printing receiving member 139 in the paper conveyance direction, a conveyance roller 141 and a spur 142 that are rotationally driven to send the paper 113 in the paper discharge direction are provided, and paper discharge that further feeds the paper 113 to the paper discharge tray 116. A roller 143 and a spur 144, and guide members 145 and 146 forming a paper discharge path are disposed.
[0101]
At the time of recording, the recording head 124 is driven according to the image signal while moving the carriage 123, thereby ejecting ink onto the stopped sheet 113 to record one line. Record the line. Upon receiving a recording end signal or a signal that the trailing edge of the sheet 113 reaches the recording area, the recording operation is terminated and the sheet 113 is discharged.
[0102]
A recovery device 147 for recovering defective ejection of the head 124 is disposed at a position outside the recording area on the right end side in the movement direction of the carriage 123. The recovery device 147 includes a cap unit, a suction unit, and a cleaning unit. The carriage 123 is moved to the recovery device 147 side during printing standby, and the head 124 is capped by the capping unit, and the ejection port portion is kept in a wet state to prevent ejection failure due to ink drying. Further, by ejecting ink that is not related to recording during recording or the like, the ink viscosity of all the ejection ports is made constant and stable ejection performance is maintained.
[0103]
When a discharge failure occurs, the discharge port (nozzle) of the head 124 is sealed with a capping unit, and bubbles and the like are sucked out from the discharge port with the suction unit through the tube. Is removed by the cleaning means to recover the ejection failure. Further, the sucked ink is discharged to a waste ink reservoir (not shown) installed at the lower part of the main body and absorbed and held by an ink absorber inside the waste ink reservoir.
[0104]
As described above, since the ink jet recording apparatus is equipped with the ink jet head which is the liquid droplet ejecting head according to the present invention, there is a recording apparatus capable of recording an image with high image quality with little variation in ink droplet ejection characteristics. can get.
[0105]
Next, a micro pump as a micro device provided with the electrostatic actuator according to the present invention will be described with reference to FIG. In addition, the figure is principal part cross-sectional explanatory drawing of the micropump.
The micropump includes a flow path substrate 201 and an actuator substrate 202 that constitutes an electrostatic actuator according to the present invention. A flow path 203 through which a fluid flows is formed in the flow path substrate 201. The actuator substrate 202 has a deformable diaphragm (movable plate) 222 provided on the base substrate 221 that forms the wall surface of the flow path 201, and a deformable portion 222a of the diaphragm 222 with a predetermined gap 223. The surface is formed in a substantially flat surface. Although detailed illustration and description of the actuator substrate 202 are omitted, it is the same as that described in the embodiment of the inkjet head.
[0106]
The operation principle of this micro pump will be described. As in the case of the ink jet head described above, an electrostatic attraction force is generated between the diaphragm 222 by selectively applying a pulse potential to the electrode 224. The deformable portion 222a of the plate 222 is deformed to the electrode 224 side. Here, by sequentially driving the deformable portion 222a of the diaphragm 222 from the right side in the figure, the fluid in the channel 201 flows in the direction of the arrow, and the fluid can be transported.
[0107]
In this case, by providing the electrostatic actuator according to the present invention, it is possible to obtain a small and low-power-consumption micropump with little variation in characteristics and capable of stable liquid transportation. Although an example in which there are a plurality of deformable portions of the diaphragm is shown here, the number of deformable portions may be one. Further, in order to increase the transportation efficiency, one or more valves such as a check valve can be provided between the deformable parts.
[0108]
Next, an example of an optical device provided with the electrostatic actuator according to the present invention will be described with reference to FIG. This figure is a schematic configuration diagram of the device.
This optical device has an actuator substrate 302 including a mirror 301 whose surface can reflect light and can be deformed. A dielectric multilayer film or a metal film is preferably formed on the surface of the mirror 301 in order to increase the reflectance (these are formed on the resin film surface).
[0109]
The actuator substrate 302 includes a deformable mirror 301 (corresponding to the vibration plate of the head) provided on the base substrate 321, and an electrode 324 that faces the deformable portion 301 of the mirror 301 via a predetermined gap 323. Including. The actuator substrate 302 is also different from that described in the embodiment of the ink jet head in that the diaphragm has a mirror surface, and detailed illustration and description thereof will be omitted.
[0110]
The principle of this optical device will be described. As in the case of the ink jet head described above, by selectively applying a pulse potential to the electrode 324, an electrostatic is generated between the deformable portion 301a of the mirror 301 facing the electrode 324. Since a suction force is generated, the deformable portion 301 of the mirror 301 is deformed into a concave shape to become a concave mirror. Therefore, when the light from the light source 310 is applied to the mirror 301 via the lens 311, when the mirror 301 is not driven, the light is reflected at the same angle as the incident angle, but when the mirror 301 is driven, the driven deformation is performed. Since the possible portion 301 becomes a concave mirror, the reflected light becomes divergent light. Thereby, an optical modulation device can be realized.
[0111]
By providing the electrostatic actuator according to the present invention, a small and low power consumption optical device with little variation in characteristics can be obtained.
[0112]
An example in which this optical device is applied will be described with reference to FIG. In this example, the above-described optical devices are arranged two-dimensionally, and the deformable portions 301a of the mirrors 301 are driven independently. Although a 4 × 4 array is shown here, it is possible to arrange more than this.
[0113]
Therefore, similarly to FIG. 17 described above, the light from the light source 310 is irradiated to the mirror 301 via the lens 311, and the light incident on the position where the mirror 301 is not driven enters the projection lens 312. On the other hand, the portion where the deformable portion 301 a of the mirror 301 is deformed by applying a voltage to the electrode 324 becomes a concave mirror, so that light diverges and hardly enters the projection lens 312. The light incident on the projection lens 312 is projected on a screen (not shown) or the like, and an image can be displayed on the screen.
[0114]
  In the above-described embodiment, the example in which the ink jet head is applied as a liquid droplet ejection head has been described. However, as a liquid droplet ejection head other than the ink jet head, for example, a liquid droplet ejection head that ejects liquid resist as liquid droplets, DNA The present invention can also be applied to other droplet discharge heads such as a droplet discharge head that discharges the sample as droplets. In addition, as a micro device equipped with an electrostatic actuator, it can also be applied to micro pumps, optical devices (light modulation devices), micro switches (micro relays), multi optical lens actuators (light switches), micro flow meters, pressure sensors, etc. can do.Further, as described above, the image forming apparatus such as a printer, a facsimile machine, and a copying apparatus and the apparatus for ejecting liquid droplets can also include the liquid droplet ejection head according to the present invention.
[0115]
【The invention's effect】
  As described above, according to the electrostatic actuator according to the present invention,In an electrostatic actuator comprising a deformable diaphragm and an electrode facing the diaphragm through a gap, and deforming the diaphragm with an electrostatic force,The diaphragm and the electrode;Are formed on the same substrate, the diaphragm has a removal hole leading to the gap, the inside of the removal hole is sealed with a sealing material, and the sealing material isIn a state where it does not enter the gapInside the removal holeSealingis doingWith the configuration, stable operating characteristics can be obtained.
[0116]
The method for manufacturing an electrostatic actuator according to the present invention is configured such that the surface of the film on which the resin film of the diaphragm is formed is exposed to a fluorine compound gas, or the surface of the film on which the resin film of the diaphragm is formed is hexafluoride. Sulfide (SF₆Since the plasma treatment is performed with gas, when the sacrificial layer removal hole is sealed with a resin material, the sacrificial layer removal hole can be sealed in a state where the sealing material does not enter the gap.
[0117]
According to the droplet discharge head according to the present invention, since the electrostatic actuator according to the present invention for pressurizing the liquid in the pressurized liquid chamber that communicates with the nozzle that discharges the droplet is provided, There is little variation in ejection characteristics, stable droplet ejection can be performed, cost reduction can be achieved, and reliability can be improved.
[0118]
According to the ink cartridge of the present invention, since the droplet discharge head according to the present invention and the ink tank that supplies ink to the droplet discharge head are integrated, there is little variation in the droplet discharge characteristics, and stable droplet discharge is achieved. It is possible to reduce the cost, and the reliability is improved.
[0119]
  According to the ink jet recording apparatus of the present invention, since the liquid droplet ejection head according to the present invention for ejecting ink droplets or the ink cartridge according to the present invention is mounted, high-quality recording is possible.According to the image forming apparatus of the present invention, since the liquid droplet ejection head according to the present invention is provided, high image quality recording is possible. In addition, according to the apparatus for ejecting droplets according to the present invention, since the droplet ejection head according to the present invention is provided, stable droplet ejection can be performed.
[0120]
The micropump according to the present invention includes the actuator substrate that constitutes the electrostatic actuator according to the present invention that pressurizes the liquid in the flow path and the flow path forming member that forms the flow path. A micro pump with power consumption can be obtained.
[0121]
According to the optical device of the present invention, since the actuator substrate constituting the electrostatic actuator according to the present invention for deforming a mirror that reflects light is provided, a small-sized and low power consumption optical device can be obtained. .
[Brief description of the drawings]
FIG. 1 is an exploded perspective view of an ink jet head according to a first embodiment of a droplet discharge head of the present invention.
FIG. 2 is an explanatory plan view of the actuator substrate of the head.
3 is a cross-sectional explanatory view taken along line X1-X1 in FIG.
4 is a cross-sectional explanatory view taken along line X2-X2 in FIG.
5 is a cross-sectional explanatory view taken along line Y1-Y1 in FIG.
6 is an explanatory cross-sectional view taken along line Y2-Y2 of FIG.
FIG. 7 is an explanatory cross-sectional view for explaining a first example of a manufacturing process of an inkjet head including a manufacturing method according to the present invention.
8 is an explanatory cross-sectional view illustrating a process following FIG.
FIG. 9 is an explanatory cross-sectional view for explaining the second example.
FIG. 10 is a cross-sectional explanatory diagram illustrating a process following FIG.
FIG. 11 is a cross-sectional explanatory view for explaining the third example.
12 is a cross-sectional explanatory diagram illustrating a process following FIG.
FIG. 13 is an explanatory perspective view for explaining the ink cartridge according to the present invention.
FIG. 14 is an explanatory perspective view illustrating an example of an ink jet recording apparatus according to the present invention.
FIG. 15 is an explanatory diagram of a mechanism unit of the recording apparatus.
FIG. 16 is an explanatory diagram illustrating an example of a micropump according to the present invention.
FIG. 17 is an explanatory diagram illustrating an example of an optical device according to the invention.
FIG. 18 is an explanatory perspective view illustrating an example of a light modulation device using the optical device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... 1st board | substrate, 2 ... 2nd board | substrate (nozzle plate), 4 ... Nozzle hole, 6 ... Discharge chamber, 7 ... Fluid resistance part, 8 ... Common liquid chamber, 11 ... Actuator board | substrate, 12 ... Channel formation member, DESCRIPTION OF SYMBOLS 21 ... Base substrate, 22 ... Diaphragm, 23 ... Gap, 24 ... Electrode, 28 ... Resin film, 41 ... Sacrificial layer removal hole, 100 ... Ink cartridge, 124 ... Recording head, 201 ... Channel substrate, 203 ... Channel 202 ... Actuator substrate, 222a ... Deformable portion, 246 ... Electrode, 301 ... Mirror, 301a ... Deformable portion, 302 ... Actuator substrate, 324 ... Electrode.

Claims (18)

In an electrostatic actuator comprising a deformable diaphragm and an electrode facing the diaphragm through a gap, and deforming the diaphragm with an electrostatic force,
The diaphragm and the electrode are formed on the same substrate,
The said diaphragm has a hole Ru leading to the gap,
Before the Kiana is sealed with a sealing material,
Electrostatic actuator the sealing material, characterized in that sealing the inside front Kiana in a state that does not enter the gap. In the electrostatic actuator according to claim 1, the planar shape before Kiana is, polygons, circles, or elliptical, electrostatic actuator, characterized in that the cross-sectional area is 10 [mu] m ² or less. In the electrostatic actuator according to claim 1 or 2, an electrostatic actuator, characterized in that the thickness before Kiana is 0.1μm or more.   4. The electrostatic actuator according to claim 1, wherein the sealing material is a part of a film constituting the diaphragm.   5. The electrostatic actuator according to claim 4, wherein the film constituting the diaphragm is a resin film that can be formed in the atmosphere.   6. The electrostatic actuator according to claim 5, wherein the resin film is a polybenzoxador (PBO) film.   7. The electrostatic actuator according to claim 5, wherein fluorine is included on a surface of a film on which the resin film of the diaphragm is formed.   7. The electrostatic actuator according to claim 5, wherein a plasma treatment is performed on a surface of the diaphragm on which the resin film is formed.   8. The method of manufacturing an electrostatic actuator according to claim 7, wherein the surface of the film on which the resin film of the diaphragm is formed is exposed to a fluorine compound gas. 10. The method for manufacturing an electrostatic actuator according to claim 9, wherein xenon difluoride (XeF ₂ ) gas is used as the fluorine compound gas. 9. The method of manufacturing an electrostatic actuator according to claim 8, wherein plasma treatment is performed with sulfur hexafluoride (SF ₆ ) gas on a surface of the diaphragm on which the resin film is formed. Manufacturing method of electrostatic actuator. In the liquid droplet discharge head nozzles for ejecting liquid droplets to eject the droplet pressurize pressurized liquid chamber of the liquid communicating with an electrostatic actuator, an electrostatic type according to any one of claims 1 to 8 A droplet discharge head comprising an actuator.   An ink cartridge in which a droplet discharge head that discharges ink droplets and an ink tank that supplies ink to the droplet discharge head are integrated, wherein the droplet discharge head is the droplet discharge head according to claim 12. A characteristic ink cartridge.   An inkjet recording apparatus equipped with an inkjet head for ejecting ink droplets, wherein the inkjet head is the droplet ejection head according to claim 12 or the droplet ejection head of the ink cartridge according to claim 13. Inkjet recording device. A micropump for transporting the liquid by pressurizing a liquid in a flow path with an electrostatic actuator, comprising the electrostatic actuator according to any one of claims 1 to 8 . An optical device that changes a light reflection direction by deforming a mirror that reflects light with an electrostatic actuator, comprising the electrostatic actuator according to any one of claims 1 to 8 . An optical device characterized by that.   13. An image forming apparatus provided with a droplet discharge head, comprising the droplet discharge head according to claim 12.   An apparatus for ejecting liquid droplets from a liquid droplet ejection head, comprising the liquid droplet ejection head according to claim 12.

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