JP2005066401A - Liquid droplet discharge apparatus, electrooptical apparatus, production method of electrooptical apparatus, and electronic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid droplet discharge apparatus capable of accurately and stably performing liquid droplet weighing. <P>SOLUTION: The liquid droplet discharge apparatus for drawing on a drawing object by discharging liquid droplets through a discharge head 103 is equipped with the following: a detection means composed of a piezoelectric vibrator 106 having electrodes 110a, 110b on both sides of it; a position deducing means which deduces a prescribed position, whereto liquid droplets are attached, on the electrode 110b and which calculates the transfer amount of transferring at least either the discharge head or the piezoelectric vibrator to the deduced prescribed position; a transfer means which transfers, based on the transfer amount, at least either the discharge head or the piezoelectric vibrator to the deduced prescribed position; an oscillating means which oscillates the piezoelectric vibrator by applying vibration voltage to the electrodes; and a liquid droplet weighing means which detects the change of resonance frequency of the piezoelectric vibrator between before and after the attachment of liquid droplets discharged from the discharge head to the electrodes and which, based on the detected change of resonance frequency of the piezoelectric vibrator, measures the weight of liquid droplets attached to the electrodes. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００３３】
また、共振抵抗値をＲとし、電極１１０ｂに付着した液滴の粘度をηとすると、これらの関係は、下式（２）で表すことができる。
【００３４】
【数２】

【００３５】
演算部１１３は、測定部１１２から供給される電極１１０ｂへの液滴の付着前における共振周波数ｆｂｅｆｏｒｅ、付着後における共振周波数ｆａｆｔｅｒからその変化量Δｆｒｅｑ＝ｆｂｅｆｏｒｅ−ｆａｆｔｅｒを算出した後、変化量Δｆｒｅｑを上記式（１）に代入して、液滴の重量Ｉｍを算出する。また、演算部１１３は、測定部１１２から入力される電極１１０ｂに液滴の付着後の共振抵抗値Ｒを、上記式（２）に代入して、液滴の粘度ηを算出する。演算部１１３は、算出した液滴の粘度ηおよび重量Ｉｍを制御部１０１に出力する。
【００３６】
［位置割出し部］
図８及び図９は本発明者が水晶振動子１０６を用いて行った実験結果をまとめた図である。この図を用いて実験結果を詳細に説明する。
図８に示すように、水晶１１０に取り付けられた略円形状の電極１１０ｂの中心（又は重心）（＃１）と、その電極中心（＃１）から略１ｍｍ離間した位置（＃２〜＃５）と、電極中心（＃１）から略２ｍｍ離間した位置（＃６〜＃９）とをそれぞれ液滴重量測定ポイントに設定する（全９ポイント）。各測定ポイントに同じ重量の液滴を単独で付着させ、その付着した液滴の重量を後述するＱＣＭセンサの液滴重量測定法に従って測定する。電極中心（＃１）に付着した液滴の重力測定値を１００％とした場合の各測定ポイント（＃２〜＃９）の重量測定値の割合（％）を図中に示す。
電極１１０ｂの中心＃１の液滴重量測定値を１００％とした場合、中心から略１ｍｍ離れた測定ポイント＃２〜＃５での液滴重量測定値の割合は、いずれも８７％であった。また、中心から略２ｍｍ離れた測定ポイント＃６〜＃９での液滴重量測定値の割合は、いずれも３８％であった。
【００３７】
図９は、図８での実験結果を分かり易くするために、測定ポイント＃１、＃４、＃５、＃８、＃９での液滴重量測定値の割合をグラフ上にプロットし、曲線で近似させた図である。同図において、横軸は電極中心からの距離、縦軸は電極中心＃１での液滴重量測定値を１００％とした時の、各測定ポイントでの液滴重量測定値の割合を示している。
同図から、電極中心＃１から略１ｍｍ付近に液滴が付着した場合には、電極中心＃１での重量値の８７％の重量値として測定されることが分かる。また、電極中心＃１から略２ｍｍ付近に液滴が付着した場合には、電極中心＃１での重量値の３８％の重量値として測定されることが分かる。
このように、液滴の付着位置が電極中心から離れるに従い、液滴重量の測定値が実際の液滴重量と比較して、大きく減少することが分かった。電極内で付着位置がばらつくと液滴重量測定値も大きくばらつくことが分かった。
また、最も感度（水晶振動子の共振周波数変化のし易さの度合い）の良い電極の重心点上に液滴を付着させることで、最も正確な液滴重量測定ができることが分かった。
この発明者の実験結果から、液滴重量を測定する場合に、電極への液滴付着位置のばらつきをなくすこと、及び、電極の重心位置に液滴を付着することが必要であるという知見が得られた。
【００３８】
ここで、図１に示すように、液滴吐出装置１００は、電極１１０ｂの所定位置に液滴を付着させるために、位置割出し部１４０を有している。
この位置割出し部１４０は、水晶振動子１０６を撮像するＣＣＤカメラを有する撮像部１４１と、その撮像した画像データを画像処理し、電極１１０ｂの所定位置を演算し、その演算結果を示す所定位置データに基づいて、水晶振動子１０６及び吐出ヘッド１０３の少なくともいずれか一方の移動量を演算する位置演算部１４２を備えている。
【００３９】
ここで位置割出し部１４０の動作について詳しく説明する。
位置割出し部１４０は、アライメント（位置決め）を行う。本実施の形態において、位置割出し部１４０は、パターンマッチングという方法を用いてアライメントを行う。
最初に、制御部１０１からの信号に従って、撮像部１４１のＣＣＤカメラで水晶振動子１０６の電極１１０ｂ及び水晶１１０周りを撮像する。次に、位置演算部１４２は、その撮像された画像データを白黒濃淡画像（グレー画像）に処理する。次に、この白黒濃淡画像に対して２値化処理を施す。即ち、ある閾値より明るい階調はすべて白、暗い階調はすべて黒に２分する。本実施形態では、電極１１０ｂ内の液滴を付着すべき所定位置を割り出すために、まず上記画像データの中から電極１１０ｂを認識する必要がある。そのため、上記閾値は、２値化により上記画像データが、その検出されるべき電極１１０ｂと、電極１１０ｂ以外の部分とに、白／黒で分かれるように設定される。位置演算部１４２は、認識した電極１１０ｂの形状を示す形状データに基づいて演算処理し、電極１１０ｂ上の液滴を付着させる所定位置を割出す。本実施の形態では、所定位置を電極１１０ｂの重心位置として設定しているので、認識された電極１１０ｂ内の重心位置を演算処理し割出すことになる。
また、位置演算部１４２は、吐出ヘッド１０３の位置、撮像部（ＣＣＤカメラ）１４１の位置などの初期データと、割出した所定位置のデータを併せて演算処理し、電極１１０ｂの所定位置に液滴が吐出される位置に吐出ヘッド１０３を配置するための、吐出ヘッド１０３及び水晶振動子１０６の少なくともいずれか一方の移動量を算出する。そして、位置演算部１４２は、その移動量を示すデータを制御部１０１に送る。制御部１０１は、その送られた移動量データに基づいて、ヘッドキャリッジ１０２を動作させて、吐出ヘッド１０３を主走査方向（Ｘ軸方向）に搬送させる。また、制御部１０１は、移動量データに基づいて、センサキャリッジ１４３を動作させて、水晶振動子１０６を副走査方向（Ｙ軸方向）に搬送させる。その結果、吐出ヘッド１０３と水晶振動子１０６とを相対的に移動させることで、電極１１０ｂ上の所定位置に液滴が吐出される位置に吐出ヘッド１０３を配置することができる。
【００４０】
上記では、パターンマッチングを用いたアライメント法について説明したが、この他のアライメント方法として、位置合せ用マークを用いた方法を用いることができる。水晶振動子１０６の電極１１０ｂ側の面に位置合わせ用マークを形成しておく。この位置合わせ用マークと電極１１０ｂ上の所定位置との相対的位置関係は分かっている。この方法によれば、パターンマッチング法のように電極１１０ｂを認識する必要が無く、位置合わせ用マークの位置さえ認識すれば、その位置合わせ用マークとの相対的位置関係により、電極１１０ｂ上の所定位置を認識することができる。
【００４１】
なお、アライメントの方法も多種類あるが、本発明の、電極１１０ｂ上の液滴を付着させる所定位置を割出すという目的を達成できれば、方法は問わない。
また、撮像部１４１は本実施の形態ではＣＣＤカメラを用いたが、別の画像センサ付きカメラを用いても良い。
【００４２】
図１０は、電極の形状と、その形状における液滴を付着させるべき所定位置を例示した図である。図１０（ａ）は、電極形状が略真円である場合を示しており、同様に、（ｂ）は略楕円、（ｃ）は略正方形、（ｅ）は略長方形、（ｆ）は略三角形、（ｇ）は略八角形をそれぞれ示している。図１０（ａ）〜（ｆ）の各形状において、電極の厚さは、ほぼ一定である場合を想定している。また、重心点は（ｘ，ｙ）として記載している。
実施の形態１に係る電極１１０ｂの形状は、略円形状（ａ）であり、重心点である円形状の中心点の（ｈ／２，ｈ／２）部が最も感度が良く、最も正確な液滴重量測定が行えるため、所定位置（ｘ，ｙ）となる。
その他の電極形状の場合の所定位置（重心点）を説明すると、電極形状が略楕円形状（ｂ）の場合は（ｂ／２，ａ／２）部が最も感度が良い所定位置（ｘ，ｙ）となる。電極形状が略正方形（ｃ）の場合は（ｈ／２，ｈ／２）部が最も感度が良い所定位置（ｘ，ｙ）となる。電極形状が略長方形（ｄ）の場合は（ｂ／２，ｈ／２）部が最も感度が良い所定位置（ｘ，ｙ）となる。電極形状が略三角形（ｅ）の場合は（ｂ／２，ｈ／３）部が最も感度が良い所定位置（ｘ，ｙ）となる。電極形状が略八方形（ｆ）の場合は（ｈ／２，ｈ／２）部が最も感度が良い所定位置（ｘ，ｙ）となる。その他の電極形状においても、重心点が最も感度の良い所定位置となる。
このように各電極形状で最も感度の良い部分が重心点として決まるので、その位置を所定位置として、アライメントすることで、最も正確な液滴重量測定が行えることになる。
【００４３】
［液滴重量の測定フロー］
図１１は、図１の液滴吐出装置１００の液滴重量の測定フローを例示する図である。
ここで、吐出ヘッド１０３は、水晶振動子１０６上になく待機位置にあるものとする。図１１において、最初に、液滴を付着する電極１１０ｂ上の中心位置（図３の地点ＰＥ及び図８の＃１ポイント参照）を割出すアライメントを行うため、位置割出し部１４０での動作が開始する。まず、撮像部１４１により水晶振動子１０６の電極１１０ｂ及び水晶１１０周りを撮像する（ステップ１）。次に、撮像した画像データに基づいて、位置演算部１４２は画像処理（２値化処理）を行い、画像上で検出すべき電極１１０ｂと電極１１０ｂ以外の部分に分けて、電極１１０ｂを認識する（ステップ２）。次に、認識した電極１１０ｂの形状データを基に演算処理し、電極１１０ｂ上の液滴を付着させる所定位置を割出す（ステップ３）。このステップ３では、上述した図１０の（ｘ，ｙ）の点が所定位置として求められる。
次に、位置演算部１４２は、吐出ヘッド１０３の位置、撮像部１４１の位置などの初期データと、割出した所定位置（ｘ，ｙ）のデータを併せて演算処理し、電極１１０ｂの所定位置（ｘ，ｙ）に液滴が吐出される位置に吐出ヘッド１０３を配置させるための吐出ヘッド１０３の移動量、水晶振動子１０６の移動量を算出する。そして、位置演算部１４２は、その算出した移動量のデータを制御部１０１に送る（ステップ４）。
【００４４】
次に、計測部１０７において、振動電圧発生部１１１は、水晶振動子１０６の電極１１０ａに振動電圧を周波数掃引しながら印加する（ステップＳ５）。測定部１１２は、水晶振動子１０６の電極１１０ｂに流れる電流を検出してインピーダンスの変化を検出し、水晶振動子１０６の電極１１０ｂへの液滴の付着前の共振周波数ｆｂｅｆｏｒｅを算出して、演算部１１３に出力する（ステップＳ６）。なお、電極１１０ｂへの液滴の付着前の共振周波数ｆｂｅｆｏｒｅは、毎回測定しないで予め演算部１１３に記憶しておくことにしても良い。
【００４５】
次に、制御部１０１は、位置演算部１４２から送られた移動量のデータを基に、ヘッドキャリッジ１０２を制御して吐出ヘッド１０３を主走査方向（Ｘ軸方向）に搬送させる（ステップＳ７）。同じく、制御部１０１は、位置演算部１４２から送られた移動量のデータを基に、センサキャリッジ１４３を制御して水晶振動子１０６を副走査方向（Ｙ軸方向）に搬送させる（ステップＳ８）。その結果、吐出ヘッド１０３と水晶振動子１０６を相対的に移動することで、電極１１０ｂの所定位置（ｘ，ｙ）に液滴が吐出される位置に吐出ヘッド１０３を配置させることができる。
【００４６】
なお、吐出ヘッド１０３及び水晶振動子１０６のいずれか一方が主走査方向及び副走査方向の双方に移動可能であれば、その吐出ヘッド１０３及び水晶振動子１０６のいずれか一方だけを移動させることにより、電極１１０ｂの所定位置（ｘ，ｙ）に液滴が吐出される位置に吐出ヘッド１０３を配置させることができる。
【００４７】
続いて、制御部１０１は、標準駆動波形に従って、吐出ヘッド１０３に含まれるピエゾ素子１２２に駆動信号を供給して、吐出ヘッド１０３から電極１１０ｂの所定位置に向けて液滴を吐出させる（ステップＳ９）。この結果、電極１１０ｂの正確な所定位置に液滴が付着することになる。
【００４８】
この後、制御部１０１は、ヘッドキャリッジ１０２を制御して吐出ヘッド１０３を待機位置まで搬送する（ステップＳ１０）。
【００４９】
この後、計測部１０７において、振動電圧発生部１１１は、水晶振動子１０６の電極１１０ａに振動電圧を周波数掃引しながら印加する（ステップＳ１１）。測定部１１２は、水晶振動子１０６の電極１１０ｂに流れる電流を検出してインピーダンスの変化を検出し、水晶振動子１０６の電極１１０ｂへの液滴の付着後の共振周波数ｆａｆｔｅｒと、そのときの共振抵抗Ｒを算出して、演算部１１３に出力する（ステップＳ１２）。
【００５０】
演算部１１３は、共振周波数ｆｂｅｆｏｒｅ、ｆａｆｔｅｒに基づいて、共振周波数の変化量Δｆｒｅｑ＝ｆｂｅｆｏｒｅ−ｆａｆｔｅｒを算出し、算出したΔｆｒｅｑを上述した式（１）を用いて液滴の重量Ｉｍを算出する（ステップＳ１３）。また、演算部１１３は、共振抵抗Ｒに基づいて、上述した式（２）を用いて液滴の粘度ηを算出する。演算部１１３は、算出した液滴の重量Ｉｍおよび粘度ηを制御部１０１に出力する。制御部１０１は、算出された液滴の重量Ｉｍおよび液滴の粘度ηを表示部１０８に表示する（ステップＳ１４）。以上のようにして液滴重量が測定される。
【００５１】
本実施の形態１の液滴吐出装置１００によれば、位置割出し部１４０により、電極１１０ｂ上において液滴を付着させるべき所定位置を割出すことができる。また割出された所定の位置データに基づいて、吐出ヘッド１０３及び水晶振動子１０６の少なくともいずれか一方の移動量が算出され、その算出結果に従って、吐出ヘッド１０３及び水晶振動子１０６の少なくともいずれか一方を移動させる。
その結果、電極１１０ｂ上の所定位置に液滴が吐出される位置に吐出ヘッド１０３が配置されることになり、電極１１０ｂの所定位置に液滴を付着することができる。よって、電極１１０ｂ上における液滴の付着位置のばらつきが改善される。また、水晶振動子１０６の製造ばらつき及び装置１００への組立てばらつきによる電極１１０ｂにおける液滴の付着位置のばらつきも解消される。従って、高精度で安定した液滴の重量測定を行うことが可能となる。
【００５２】
また、位置割出し部１４０は、撮像部１４１と、位置演算部１４２を備えているので、電極１１０ｂの所定位置に対するアライメントが簡単に行える。
【００５３】
また、電極１１０ｂの重心点上に液滴を付着させた場合には、電極１１０ｂのの重心点以外の位置に液滴を付着させた場合に比べて、水晶振動子１０６の共振周波数が最も下がる。即ち、電極１１０ｂの重心点に液滴が付着された場合に、液滴の付着前後の共振周波数の変化量が最大となる。このように、最も高感度である電極の重心点上に液滴を付着させることで、最も正確で信頼性の高い液滴の重量測定が可能となる。例えば、円形状の電極１１０ｂの場合だと、重心点である電極の中心点上が最も感度が良いため、円形状の重心点（中心点）上を所定位置とすることで、最も正確で信頼性の高い液滴重量測定が可能となる。
また、一般に、吐出ヘッドから吐出される液滴は、周囲の環境や自重等により予想外に飛行曲がりを起こし、その結果、液滴の付着位置が当初の狙いからずれることがある。これに対し、本実施形態では、所定位置を電極１１０ｂの重心点上に設定し、かつ、その電極１１０ｂの所定位置に液滴が吐出される位置に吐出ヘッド１０３を配置するので、その吐出ヘッド１０３から吐出された液滴に飛行曲がりが起きて付着位置がずれたとしても、重心点からのズレ量は相対的に僅かなものに抑えることができる（付着位置は重心位置の近傍におさまる）。これにより、ほぼ正確な液滴重量測定が実現できる。
【００５４】
（実施の形態２）
図１２は、本発明の実施の形態２に係る液滴吐出装置を用いて製造された、電気光学装置であるカラーフィルタを搭載した液晶表示装置の構成を例示する斜視図である。
本実施の形態２に係る液晶表示装置２００は、液晶駆動用ＩＣ（図示略）、配線類（図示略）、光源２８０、支持体（図示略）などの付帯要素が装着されている。液晶表示装置２００の構成を簡単に説明する。
液晶表示装置２００は、カラーフィルタ２１０と、ガラス基板２３０と、これらの間に狭持された液晶層（図示略）と、カラーフィルタ２１０の上面側に付設された偏光板２４０と、ガラス基板２３０側の下面側に付設された偏光板（図示略）と、を主体として構成されている。カラーフィルタ２１０は透明なガラスから成る基板２１１を具備し、基板２１１の下側には、黒色感光性樹脂膜から成る隔壁２１２と、着色部２１３と、オーバーコート層２１４が順次形成され、オーバーコート層２１４の下側に液晶駆動用の電極２２０が形成されている。なお、実際の液晶表示装置においては、電極２２０の液晶層側と、画素電極２６０の液晶層側に、配向膜が設けられる（図示略）。
カラーフィルタ２１０の液晶層側に形成された液晶駆動用の電極２２０は、ＩＴＯ（Ｉｎｄｉｕｍ Ｔｉｎ Ｏｘｉｄｅ）などの透明導電材料をオーバーコート層２１４の全面に形成させたものである。
【００５５】
ガラス基板２３０上に形成された絶縁層２５０上には、マトリクス状に走査線２７０と信号線２７１とが形成され、走査線２７０と信号線２７１とに囲まれた領域ごとに画素電極２６０が設けられる。各画素電極２６０のコーナー部分と走査線２７０と信号線２７１との間部分にはスイッチング素子としてのＴＦＴ（Ｔｈｉｎ Ｆｉｌｍ Ｔｒａｎｓｉｓｔｏｒ）が組み込まれており、走査線２７０と信号線２７１に対する信号の印加によってＴＦＴはオン、またはオフの状態となって画素電極２６０への通電が制御されるようになっている。
【００５６】
本実施の形態２のカラーフィルタ２１０以外にも、本発明の液滴吐出装置１００を用いれば、金属配線用材料、マイクロレンズアレイ用材料、フォトレジスト用材料、エレクトロルミネセンス用材料、生体物質材料などの様々な液状材料を正確な液滴重量で基板Ｗ上に吐出形成することができる。よって、本発明の液滴吐出装置１００を用いれば、高品質で様々な電気光学装置が製造可能となる。
【００５７】
（実施の形態３）
図１３は、本発明の実施の形態３に係る電気光学装置である液晶表示装置を備えた電子機器の一例として、携帯電話の構成を例示する斜視図である。携帯電話機３００は複数の操作スイッチ３１０のほか、受話口３１１、送話口３１２と共に、上述した液晶表示装置２００を備えるものである。
【００５８】
また、携帯電話機３００以外にも、本発明の液滴吐出装置を用いて製造された電気光学装置はコンピュータや、プロジェクタ、デジタルカメラ、ムービーカメラ、ＰＤＡ（Ｐｅｒｓｏｎａｌ Ｄｉｇｉｔａｌ Ａｓｓｉｓｔａｎｔ）、車載機器、複写機、オーディオ機器などの様々な電子機器の表示部として用いることができる。
【００５９】
なお、本発明は、上記した実施の形態１〜実施の形態３に限定されるものではなく、発明の要旨を変更しない範囲で適宜変形しても実施可能である。
【図面の簡単な説明】
【図１】本発明の実施の形態１に係る液滴吐出装置の全体の概略構成図である。
【図２】吐出ヘッドの詳細な構成図である。
【図３】ＱＣＭセンサの構成を示す平面図である。
【図４】水晶振動子の等価回路図である。
【図５】計測部の概念図である。
【図６】帰還型の自励発振方式の概念図である。
【図７】水晶振動子のアドミッタンス線図である。
【図８】液滴付着位置の測定ポイントにおける液滴重量測定値の割合を電極上に記載した説明図である。
【図９】液滴付着位置の電極中心からの距離と液滴重量測定値の割合を曲線で近似した説明図である。
【図１０】本発明の実施の形態１に係る電極の形状による、液滴を付着させる所定位置の例示図である。
【図１１】本発明の実施の形態１に係る液滴吐出装置の液滴重量測定フローの例示図である。
【図１２】本発明の実施の形態２に係る液晶表示装置の例示図である。
【図１３】本発明の実施の形態３に係る液晶表示装置を備えた携帯電話機の例示図である。
【符号の説明】
１００・・液滴吐出装置、１０１・・制御部、１０２・・ヘッドキャリッジ、１０３Ｒ、１０３Ｇ、１０３Ｂ・・吐出ヘッド、１０４Ｒ、１０４Ｇ、１０４Ｂ・・インクタンク、１０５・・ステージ、１０６・・水晶振動子、１０７・・計測部、１０８・・表示部、 １１０・・水晶、１１０ａ、１１０ｂ・・電極、１１１・・振動電圧発生部、１１２・・測定部、１１３・・演算部、１４０・・位置割出し部、１４１・・撮像部、１４２・・位置演算部、１４３・・センサキャリッジ、２００・・液晶表示装置、３００・・携帯電話機[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a droplet discharge device, and more particularly to a droplet discharge device, an electro-optical device, an electro-optical device manufacturing method, and an electronic apparatus that can accurately measure the weight of a droplet discharged from a discharge head.
[0002]
[Prior art]
For example, a droplet discharge device is used for forming a color filter, an alignment film, and the like of a liquid crystal display device. In addition, the droplet discharge device is used in various industrial fields. The droplet discharge device has a droplet discharge mechanism called a discharge head. A plurality of nozzles are regularly formed in the discharge head. In a droplet discharge device, a pattern made of a discharge material is drawn on a substrate which is a component of some product by discharging a droplet of the discharge material from these nozzles. As a device for measuring the weight of droplets ejected from the ejection head, for example, the following micro droplet weight device is known (for example, see Patent Document 1).
[0003]
This device is equipped with a heater on a piezoelectric vibrating body with a diaphragm and a piezoelectric element bonded together, and does not peel off or evaporate even if hot melt ink (ink made by dissolving solid material) adheres to the piezoelectric vibrating body. A hot melt ink jet is sprayed in a state where the piezoelectric vibrator is controlled. When hot melt ink adheres, the electromechanical coupling coefficient of the piezoelectric vibrator changes, and the impedance of the piezoelectric element changes in proportion to the weight of the adhesion. The adhesion weight is calculated from the amount of change in impedance.
[0004]
[Patent Document 1]
JP 7-248250 A
[0005]
[Problems to be solved by the invention]
By the way, according to an experiment by the present inventor, it has been found that when a droplet adheres to the electrode of the piezoelectric vibrator, the weight measurement value of the droplet greatly varies depending on the position in the electrode. That is, even when the actual droplets have the same weight, the weight when the droplets are attached to a position away from the center of gravity of the electrode is more than the weight when the droplets are attached to the center of gravity of the electrode. The knowledge that it was measured as a small value was obtained.
In addition, due to variations in manufacturing of piezoelectric vibrators and attachment of piezoelectric vibrators to the device, the attachment position of the liquid droplets in the electrodes may be displaced, which hinders accurate measurement of the liquid drop weight. It has also been found by the inventors' experiments.
On the other hand, in the above-described conventional apparatus, only the point where the droplet adheres on the diaphragm when measuring the weight of the droplet is shown, and there is no matter about the variation in the attachment position in the electrode and the measurement accuracy. Not shown.
[0006]
The present invention has been made in view of the above problems, and a droplet discharge device capable of accurate and stable droplet weight measurement, a method of manufacturing an electro-optical device using the droplet discharge device, and the electro-optical device It is an object of the present invention to provide an electro-optical device manufactured by using the manufacturing method and an electronic apparatus including the electro-optical device.
[0007]
[Means for Solving the Problems]
In order to solve the above-described problems and achieve the object, according to the present invention, a droplet discharge device that discharges droplets from a discharge head to draw on a drawing object includes a piezoelectric vibrator having electrodes on both sides. A detection unit and a predetermined position on the electrode where a droplet should be attached are indexed, and a movement amount for moving at least one of the ejection head or the piezoelectric vibrator to the calculated predetermined position is calculated. A position indexing means; a moving means for moving at least one of the ejection head or the piezoelectric vibrator to the indexed predetermined position based on the amount of movement; An oscillation unit that vibrates the piezoelectric vibrator, and a change in the resonance frequency of the piezoelectric vibrator before and after the droplet ejected from the ejection head adheres to the electrode, and detects the detected pressure Based on the change in the resonance frequency of the vibrator, and drop weight measuring means for measuring the weight of the liquid droplets adhering to the electrode, further comprising a can to provide a droplet ejection apparatus characterized.
[0008]
With this configuration, it is possible to determine a predetermined position on the electrode where the droplet should be deposited by the position indexing unit. Further, the movement amount is calculated based on the data of the determined predetermined position. Then, at least one of the head that discharges the droplet and the piezoelectric vibrator moves by the calculated amount of movement. As a result, the head is positioned at a position where the droplet is ejected at a predetermined position on the electrode, and the droplet can be attached to the predetermined position. Therefore, the variation in the adhesion position on the electrode is improved. Further, the variation in the attachment position due to the manufacturing variation of the piezoelectric vibrator and the assembly variation to the apparatus is also eliminated. It is thus possible to obtain a stable and constant drop weight measurement.
[0009]
According to still another preferable aspect of the present invention, it is desirable that the position indexing unit indexes the predetermined position from an image capturing unit for capturing an image of the electrode and the captured image, and calculates the position. Thereby, alignment (positioning) of a predetermined position can be easily performed.
[0010]
According to a preferred aspect of the present invention, it is desirable that the predetermined position is on the center of gravity of the electrode. When a droplet adheres on the center of gravity of the electrode, the resonance frequency of the piezoelectric vibrator is lowest. That is, when a droplet adheres to the center of gravity of the electrode, the amount of change in the resonance frequency of the piezoelectric vibrator before and after the droplet is adhered is maximized. By attaching the droplet on the center of gravity of the electrode having the best sensitivity (the degree of ease of changing the resonance frequency of the piezoelectric vibrator), the most accurate and reliable droplet weight measurement can be performed. For example, in the case of a circular electrode, the thickness of the electrode is constant, and the sensitivity is best on the center point of the electrode, which is the center of gravity. Therefore, the circular center of gravity (center point) is set at a predetermined position. This enables the most accurate and reliable droplet weight measurement.
[0011]
The electro-optical device manufacturing method according to the present invention is characterized by using the above-described droplet discharge device of the present invention.
[0012]
In addition, an electro-optical device according to the present invention is manufactured using the method for manufacturing an electro-optical device according to the present invention.
[0013]
By using a droplet discharge device, various liquid materials such as color filter materials, metal wiring materials, microlens array materials, photoresist materials, electroluminescence materials, and biological material materials can be accurately dropped. It can be discharged and formed on the substrate by weight. Therefore, various electro-optical devices with high quality can be manufactured.
[0014]
An electronic apparatus according to the present invention includes the electro-optical device according to the present invention.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Preferred embodiments of a droplet discharge device according to the present invention will be described below with reference to the accompanying drawings.
[0016]
(Embodiment 1)
The droplet discharge device according to the first embodiment of the present invention includes the following: [Entire configuration of droplet discharge device], [Discharge head], [QCM sensor], [Measurement principle of droplet weight], [Position indexing unit] , [Droplet Weight Measurement Flow] will be described in this order.
[0017]
[Entire configuration of droplet discharge device]
FIG. 1 is a diagram showing an overall schematic configuration of a droplet discharge apparatus 100 according to Embodiment 1 of the present invention. The droplet discharge apparatus 100 according to the present embodiment mainly includes a control unit 101, a head carriage 102, discharge heads 103R, 103G, and 103B, ink tanks 104R, 104G, and 104B, a stage 105, and a crystal resonator 106. Including a QCM (Quartz-Crystal Microbalance) sensor, a measurement unit 107, a display unit 108, a position indexing unit 140, and a sensor carriage 143.
[0018]
The control unit 101 includes a CPU (Central Processing Unit), a ROM, a RAM, and the like, and controls the entire droplet discharge device 100. Specifically, the control unit 101 controls the operation of drawing with the discharge heads 103R, 103G, and 103B on the target object W such as a substrate placed on the stage 105, and is discharged from the discharge heads 103R, 103G, and 103B. Control of the operation for measuring the weight of the liquid droplets, and the operation for indexing the position where the droplets are attached to the electrode 110b. The head carriage 102 conveys the ejection heads 103R, 103G, and 103B in the main scanning direction (X-axis direction) under the control of the control unit 101. The ejection heads 103 </ b> R, 103 </ b> G, and 103 </ b> B are carried by the head carriage 102 and move together with the head carriage 102, and eject liquid droplets from the nozzles according to a drive signal input from the control unit 101.
[0019]
The ink tanks 104R, 104G, and 104B are filled with R, G, and B inks, and supply the R, G, and B inks to the ejection heads 103R, 103G, and 103B, respectively. On the stage 105, a drawing object W such as a substrate is placed and conveyed in the sub-scanning direction (Y-axis direction) by a drive mechanism (not shown) under the control of the control unit 101. The crystal resonator 106 includes a crystal 110 and a first electrode 110 a and a second electrode 110 b formed on both surfaces of the crystal 110. The crystal resonator 106 is used when measuring the weight of the droplets ejected from the ejection heads 103R, 103G, and 103B. The measurement unit 107 applies a vibration voltage to the first electrode 110a of the crystal resonator 106, and the weight of the droplet attached to the second electrode 110b based on the current output from the second electrode 110b. And the measurement result is output to the control unit 101.
The position indexing unit 140 includes an imaging unit 141 equipped with a CCD camera and a position calculating unit 142, and performs alignment (positioning). The position indexing unit 140 indexes the position where the droplet is deposited on the second electrode 110b according to the control of the control unit 101, and based on the indexing result, the ejection heads 103R, 103G, and 103B and the crystal resonator 106 are controlled. At least one of the movement amounts is calculated, and the calculation result is output to the control unit 101.
The sensor carriage 143 conveys the crystal unit 106 in the sub-scanning direction (Y-axis direction) under the control of the control unit 101. The display unit 108 is composed of, for example, an LCD monitor, and displays the measurement result of the weight of the droplets according to the control of the control unit 101.
[0020]
[Discharge head]
FIG. 2 is a diagram showing a detailed configuration of the ejection head 103R in FIG. As shown in FIG. 2, the ejection head 103 </ b> R includes a pressure chamber 121, a piezo element 122, and a nozzle 123. The pressure chamber 121 communicates with the ink tank 104R and temporarily stores the red ink supplied from the ink tank 104R. As is well known, the piezo element 122 is an element that transforms electro-mechanical energy at an extremely high speed by distorting the crystal structure when a voltage is applied. The piezo element 122 deforms the inner surface of the pressure chamber 121 according to the drive signal supplied from the control unit 101, and increases or decreases the pressure of the red ink in the pressure chamber 121. In the ejection head 103R, the red ink is ejected as a droplet IP from the nozzle 123 in accordance with the pressure increase / decrease of the red ink by the piezo element 122.
[0021]
The ejection head 103G has the same configuration as the ejection head 103R, and ejects the green ink supplied from the ink tank 104G as droplets in accordance with the drive signal supplied from the control unit 101. Similarly, the ejection head 103B ejects blue ink supplied from the ink tank 104B as droplets in response to a drive signal supplied from the control unit 101. In this embodiment, for convenience of explanation, red ink, green ink, and blue ink have their liquid properties (for example, viscosity characteristics according to temperature) substantially the same, and under the same conditions, It shall exhibit similar fluid behavior. Therefore, if the conditions for droplet ejection are exactly the same, the same amount of droplets is ejected regardless of which ink is used. In the following description, when it is not necessary to distinguish each of the ejection heads 103R, 103G, and 103B, the ejection head 103 is described, and similarly, each of the ink tanks 104R, 104G, and 104B is particularly distinguished. When it is not necessary to do this, it is described as an ink tank 104.
[0022]
[QCM sensor]
FIG. 3 is a plan view showing the configuration of the crystal unit 106 of FIG. The crystal 110 has a substantially square shape, and a pair of electrodes 110a and 110b are attached to both surfaces thereof so as to face each other. The pair of electrodes 110a and 110b can be made of a metal such as Au or Pt. Further, the insulator 131 holds the crystal 110 in a freely oscillating manner by the conductive supports 133a and 133b. The support 133a is electrically connected to the electrode 110a and electrically connected to the terminal 132a fixed to the insulator 131. Similarly, the support 133b is electrically connected to the electrode 110b and is electrically connected to the terminal 132b fixed to the insulator 131. Moreover, in the same figure, PE has shown the approximate center position of the electrode 110b.
[0023]
FIG. 4 shows an equivalent circuit of the crystal unit 106. As shown in FIG. 4, the crystal unit 106 is electrically equivalent to an electric circuit including a resistor R1, capacitors C1 and Co, and a coil L1. Here, Co, which is a parallel capacitance, is an equivalent electrode capacitance of a capacitance component generated by the electrodes 110 a and 110 a provided on both surfaces of the crystal resonator 106. The crystal resonator 106 has an electrical natural frequency. When the electrodes 110a and 110b provided on both sides of the crystal 110 are connected to a power source, the circuit starts oscillating at the natural frequency, and the crystal resonator 106 also oscillates. Vibrates at the same frequency as the frequency. The oscillation frequency is mainly determined by the angle at which the crystal 110 is cut out with respect to the crystal growth axis and the thickness of the crystal 110, and the vibration form of the crystal 110 is determined by the angle at which the thin plate is cut out. In the QCM, a crystal 110 cut out at a predetermined angle called AT cut is usually used, and the vibration form of the AT cut crystal 110 is a thickness-shear vibration, that is, the front and back surfaces of the crystal 110 are crystal. In the direction perpendicular to the thickness direction of 110, the vibrations are caused to deviate from each other.
[0024]
If the external force acting on the crystal resonator 106 is constant, the crystal resonator 106 vibrates at a constant resonance frequency. However, when the external force changes due to the droplets adhering to the electrode 110b, the resonance frequency changes according to the amount of change. It has the property of changing. In other words, when a droplet adheres to the electrode 110b, the crystal resonator 106 has a characteristic of vibrating at a resonance frequency corresponding to the weight and viscosity of the droplet. Further, the crystal resonator 106 has a characteristic that when a liquid adheres to the electrode 110b, a resonance resistance value thereof changes according to the viscosity of the adhering liquid. As will be described later, the measurement unit 107 calculates the weight and viscosity of the droplet by using the characteristics of the crystal resonator 106.
[0025]
[Measurement principle of drop weight]
FIG. 5 shows a conceptual diagram of the measurement unit 107 of FIG. The measurement unit 107 of the present embodiment uses an external oscillation method. In FIG. 5, in the measurement unit 107, an oscillation voltage Vin (corresponding to the oscillation voltage generation unit 111) is applied to one electrode 110 a of the crystal unit 106 by an oscillator 150 to excite the crystal unit 106. The RF voltage type 151 (corresponding to the measurement unit 112) measures the current Iq = (Vq / RL) flowing from the other electrode 110b of the excited crystal unit 106. Thereby, the electrical impedance of the crystal unit 106 with respect to the frequency can be obtained from the relationship between the applied vibration voltage and the current flowing through the crystal unit 106. The impedance changes greatly near the resonance frequency. Therefore, the measurement unit 107 measures the impedance while sweeping the frequency of the applied oscillating voltage, and obtains the frequency at which the impedance is minimized. This frequency is the series resonance frequency (fs), and the resistance component at this time is the resonance resistance.
[0026]
FIG. 6 shows a conceptual diagram of a feedback type self-excited oscillation method (conventional method) used when measuring the resonance frequency of the crystal resonator 106. The external oscillation system of this embodiment will be described in comparison with the feedback self-excited oscillation system shown in FIG. In the feedback self-excited oscillation system shown in FIG. 6, the oscillation circuit including the crystal unit 106 is set in a resonance state, and the resonance frequency that changes when a droplet adheres to the electrode is measured by the frequency counter 160. Based on the measured resonance frequency, the weight of the substance attached to the electrode surface of the crystal unit 106 is measured. However, as described above, the resonance frequency of the crystal unit 106 also varies depending on the viscoelasticity of the adhered substance. For this reason, when a substance having both viscoelastic properties adheres, it cannot be determined whether the change has occurred due to either of the influences. On the other hand, it is known that resonance resistance is mainly proportional to viscoelasticity. The measurement unit 107 of the present embodiment measures both the resonance frequency and the resonance resistance to determine whether the change is due to weight or viscoelasticity.
[0027]
FIG. 7 shows an admittance diagram of the crystal unit 106. The frequency characteristics of the crystal resonator impedance represented by the equivalent circuit in FIG. 4 above were measured and plotted on an impedance plane with the G (conductance) on the X axis and the B (susceptance) component on the Y axis. Is. As shown in the figure, the entire curve is shifted on the B axis by ωCo due to the influence of the equivalent electrode capacitance Co. Since the resonance point of the feedback self-excited oscillation system is a point where the phase shift is “0”, that is, a point where the B component is “0”, it is indicated by fr in FIG. Because of Co, the resonance point shifts from fs (series resonance frequency), which is the resonance point of the original crystal resonator, to fr (generally speaking, fr is referred to as the resonance frequency).
[0028]
Here, the proportional relationship between the weight and the frequency holds true for fs. Therefore, in the feedback self-excited oscillation method based on fr, an error occurs in the relationship between weight and frequency. Specifically, as shown in (a) of the figure, when the load is small and G is large (while the resonance resistance R is small), the radius of the circle is large, so there is not much difference between the values of fs and fr. . On the other hand, as shown in (b) of the figure, when the load increases and G becomes extremely small (R becomes large), both of them become large by deviation. For this reason, in the feedback self-excited oscillation method that measures fr as the resonance frequency, linearity deteriorates as the load increases. On the other hand, in the method of measuring fs by the external oscillation method as in the present embodiment, such linearity degradation does not occur.
[0029]
Further, when the load increases and the state becomes as shown in (c) of the figure, the fr point disappears, so that the conventional feedback self-oscillation method cannot oscillate. On the other hand, in the external oscillation system according to the present embodiment, fs is measured and thus there is no influence of the equivalent electrode capacitance Co. Therefore, even in this case, the resonance point can be found. That is, the external oscillation method of the present embodiment enables measurement with a heavy load as compared with the feedback self-excited oscillation method. Further, in the feedback type self-excited transmission method, it is necessary to tune the oscillation circuit in accordance with the frequency to be used in order to obtain both stable and accurate oscillation. For this reason, it is difficult to cope with a wide range of oscillation frequencies with the same oscillation circuit. On the other hand, in the external oscillation system of the present embodiment, an oscillating voltage for oscillating the crystal resonator 106 is generated outside, so that it is possible to cope with a wide range of frequencies without changing the circuit.
[0030]
Next, the measuring unit 107 in FIG. 1 will be described in detail. The oscillating voltage generator 111 applies a oscillating voltage to one electrode 110 a of the crystal resonator 106 to vibrate the crystal resonator 106. At that time, the frequency of the oscillating voltage is changed little by little from the low frequency to the high frequency to sweep the frequency. The measuring unit 112 measures the current Iq = (Vq / RL) flowing from the other electrode 110b of the crystal resonator 106, and the crystal resonator 106 with respect to the frequency is determined from the relationship between the applied vibration voltage and the current flowing through the crystal resonator 106. The electrical impedance of is calculated. Then, the measurement unit 112 calculates a frequency (the above-described series resonance frequency fs) at which the measured impedance is minimum as the resonance frequency value, and calculates the impedance at this time as the resonance resistance value. The measurement unit 112 outputs the calculated resonance frequency value and resonance resistance value to the calculation unit 113. In this case, the measurement unit 112 outputs the resonance frequency fbefore before adhesion of the droplet to the electrode 110b and the resonance frequency after after adhesion to the calculation unit 113. The calculation unit 113 calculates the weight of the droplet based on the resonance frequencies fbefore and after input from the measurement unit 112 as described below, and based on the resonance resistance input from the measurement unit 112. Calculate the viscosity of the droplet. As described above, the weight of the droplet can be calculated based on the resonance frequencies fbefore and after, but the weight of the droplet can be calculated more accurately by using the resonance resistance.
[0031]
Here, when the weight of the droplet attached to the electrode 110b is Im, and the amount of change Δfreq of the resonance frequency before and after the attachment of the droplet, the amount of droplet Im and the amount of change Δfreq of the resonance frequency before and after the attachment of the droplet. Can be expressed as in the following formula (1).
[0032]
[Expression 1]

[0033]
Further, when the resonance resistance value is R and the viscosity of the droplet attached to the electrode 110b is η, these relationships can be expressed by the following equation (2).
[0034]
[Expression 2]

[0035]
The calculation unit 113 calculates the change amount Δfreq = fbefore-fafter from the resonance frequency fbefore before adhesion of the droplet to the electrode 110b supplied from the measurement unit 112 and the resonance frequency after adhesion, and then calculates the change amount Δfreq. Substituting into the above equation (1), the droplet weight Im is calculated. Further, the calculation unit 113 calculates the viscosity η of the droplet by substituting the resonance resistance value R after the droplet adheres to the electrode 110b input from the measurement unit 112 into the above equation (2). The calculation unit 113 outputs the calculated droplet viscosity η and weight Im to the control unit 101.
[0036]
[Position indexing section]
8 and 9 are diagrams summarizing the results of experiments conducted by the inventor using the crystal resonator 106. FIG. The experimental results will be described in detail using this figure.
As shown in FIG. 8, the center (or center of gravity) (# 1) of the substantially circular electrode 110b attached to the crystal 110, and the positions (# 2 to # 5) spaced from the electrode center (# 1) by about 1 mm. ) And positions (# 6 to # 9) spaced approximately 2 mm from the electrode center (# 1), respectively, are set as droplet weight measurement points (all 9 points). A droplet having the same weight is attached to each measurement point independently, and the weight of the attached droplet is measured according to a droplet weight measurement method of a QCM sensor described later. The figure shows the ratio (%) of the weight measurement value of each measurement point (# 2 to # 9) when the gravity measurement value of the droplet attached to the electrode center (# 1) is 100%.
When the droplet weight measurement value at the center # 1 of the electrode 110b is 100%, the ratio of the droplet weight measurement values at measurement points # 2 to # 5 that are approximately 1 mm away from the center is 87%. . In addition, the ratios of the droplet weight measurement values at measurement points # 6 to # 9 that were approximately 2 mm away from the center were all 38%.
[0037]
FIG. 9 is a graph in which the ratio of droplet weight measurement values at measurement points # 1, # 4, # 5, # 8, and # 9 is plotted on a graph to make the experimental results in FIG. 8 easy to understand. FIG. In the figure, the horizontal axis indicates the distance from the electrode center, and the vertical axis indicates the ratio of the droplet weight measurement value at each measurement point when the droplet weight measurement value at the electrode center # 1 is 100%. Yes.
From the figure, it can be seen that when a droplet adheres in the vicinity of approximately 1 mm from the electrode center # 1, it is measured as a weight value of 87% of the weight value at the electrode center # 1. Further, it can be seen that when a droplet adheres in the vicinity of approximately 2 mm from the electrode center # 1, it is measured as a weight value of 38% of the weight value at the electrode center # 1.
As described above, it was found that the measured value of the droplet weight significantly decreased as the droplet attachment position moved away from the center of the electrode as compared with the actual droplet weight. It was found that the droplet weight measurement value varied greatly when the deposition position varied within the electrode.
In addition, it was found that the most accurate droplet weight measurement can be performed by attaching a droplet on the center of gravity of the electrode having the highest sensitivity (degree of ease of changing the resonance frequency of the crystal resonator).
From the results of this inventor's experiment, it has been found that when measuring the weight of a droplet, it is necessary to eliminate variations in the droplet attachment position on the electrode and to attach the droplet to the center of gravity of the electrode. Obtained.
[0038]
Here, as shown in FIG. 1, the droplet discharge device 100 includes a position indexing unit 140 for attaching droplets to a predetermined position of the electrode 110 b.
This position indexing unit 140 performs image processing on the imaged unit 141 having a CCD camera that images the crystal resonator 106 and the captured image data, calculates a predetermined position of the electrode 110b, and a predetermined position indicating the calculation result Based on the data, a position calculation unit 142 is provided that calculates the amount of movement of at least one of the crystal unit 106 and the ejection head 103.
[0039]
Here, the operation of the position indexing unit 140 will be described in detail.
The position indexing unit 140 performs alignment (positioning). In the present embodiment, the position indexing unit 140 performs alignment using a method called pattern matching.
First, according to a signal from the control unit 101, the CCD camera of the imaging unit 141 images the electrode 110 b of the crystal resonator 106 and the periphery of the crystal 110. Next, the position calculation unit 142 processes the captured image data into a black and white image (gray image). Next, a binarization process is performed on the black and white grayscale image. That is, all the gradations brighter than a certain threshold value are divided into white, and all the dark gradations are divided into black. In this embodiment, in order to determine a predetermined position where the droplet in the electrode 110b is to be deposited, it is necessary to first recognize the electrode 110b from the image data. Therefore, the threshold value is set so that the image data is divided into white / black for the electrode 110b to be detected and a portion other than the electrode 110b by binarization. The position calculation unit 142 performs calculation processing based on the shape data indicating the shape of the recognized electrode 110b, and determines a predetermined position where the droplet on the electrode 110b is attached. In this embodiment, since the predetermined position is set as the barycentric position of the electrode 110b, the recognized barycentric position in the electrode 110b is calculated and calculated.
In addition, the position calculation unit 142 performs calculation processing on the initial data such as the position of the ejection head 103 and the position of the imaging unit (CCD camera) 141 and the data of the determined predetermined position, and performs liquid processing on the predetermined position of the electrode 110b. The amount of movement of at least one of the ejection head 103 and the crystal resonator 106 for arranging the ejection head 103 at the position where the droplet is ejected is calculated. Then, the position calculation unit 142 sends data indicating the movement amount to the control unit 101. The control unit 101 operates the head carriage 102 based on the transferred movement amount data, and transports the ejection head 103 in the main scanning direction (X-axis direction). Further, the control unit 101 operates the sensor carriage 143 based on the movement amount data to convey the crystal unit 106 in the sub-scanning direction (Y-axis direction). As a result, by relatively moving the ejection head 103 and the crystal resonator 106, the ejection head 103 can be disposed at a position where a droplet is ejected at a predetermined position on the electrode 110b.
[0040]
In the above, the alignment method using pattern matching has been described. However, as another alignment method, a method using alignment marks can be used. An alignment mark is formed on the surface of the crystal unit 106 on the electrode 110b side. The relative positional relationship between this alignment mark and a predetermined position on the electrode 110b is known. According to this method, it is not necessary to recognize the electrode 110b as in the pattern matching method. If only the position of the alignment mark is recognized, the predetermined position on the electrode 110b is determined based on the relative positional relationship with the alignment mark. The position can be recognized.
[0041]
Although there are many types of alignment methods, any method can be used as long as it can achieve the object of the present invention to determine a predetermined position where the droplet on the electrode 110b is attached.
In addition, the imaging unit 141 uses a CCD camera in this embodiment, but another camera with an image sensor may be used.
[0042]
FIG. 10 is a diagram illustrating the shape of an electrode and a predetermined position where a droplet in that shape is to be attached. FIG. 10A shows a case where the electrode shape is a substantially perfect circle. Similarly, (b) is a substantially ellipse, (c) is a substantially square, (e) is a substantially rectangular, and (f) is a substantially round shape. Triangles and (g) indicate substantially octagons, respectively. In each shape of FIGS. 10A to 10F, it is assumed that the thickness of the electrode is substantially constant. The center of gravity is described as (x, y).
The shape of the electrode 110b according to the first embodiment is a substantially circular shape (a), and the (h / 2, h / 2) portion of the circular center point that is the center of gravity is the most sensitive and most accurate. Since the droplet weight can be measured, the predetermined position (x, y) is obtained.
The predetermined position (centroid point) in the case of other electrode shapes will be described. When the electrode shape is a substantially elliptical shape (b), the (b / 2, a / 2) portion has the most sensitive predetermined position (x, y). ) When the electrode shape is substantially square (c), the (h / 2, h / 2) portion is the predetermined position (x, y) with the highest sensitivity. When the electrode shape is substantially rectangular (d), the (b / 2, h / 2) portion is the predetermined position (x, y) with the highest sensitivity. When the electrode shape is substantially a triangle (e), the (b / 2, h / 3) portion is the predetermined position (x, y) with the highest sensitivity. When the electrode shape is substantially octagonal (f), the (h / 2, h / 2) portion is the predetermined position (x, y) with the highest sensitivity. In other electrode shapes, the center of gravity is the most sensitive predetermined position.
As described above, the most sensitive portion of each electrode shape is determined as the barycentric point, and the most accurate droplet weight measurement can be performed by aligning the position as a predetermined position.
[0043]
[Drop weight measurement flow]
FIG. 11 is a diagram illustrating a measurement flow of the droplet weight of the droplet discharge device 100 of FIG.
Here, it is assumed that the ejection head 103 is not on the crystal unit 106 but is in a standby position. In FIG. 11, first, the alignment in the position indexing unit 140 is performed in order to perform alignment for indexing the center position on the electrode 110b to which the droplet is attached (see point PE in FIG. 3 and point # 1 in FIG. 8). Start. First, the imaging unit 141 images the electrode 110b of the crystal unit 106 and the periphery of the crystal 110 (step 1). Next, the position calculation unit 142 performs image processing (binarization processing) based on the captured image data, and recognizes the electrode 110b by dividing it into portions other than the electrode 110b and the electrode 110b to be detected on the image. (Step 2). Next, calculation processing is performed based on the recognized shape data of the electrode 110b, and a predetermined position where the droplet on the electrode 110b is attached is determined (step 3). In step 3, the point (x, y) in FIG. 10 described above is obtained as a predetermined position.
Next, the position calculation unit 142 performs calculation processing on the initial data such as the position of the ejection head 103 and the position of the imaging unit 141 and the data of the determined predetermined position (x, y), and performs a predetermined process on the electrode 110b. The movement amount of the ejection head 103 and the movement amount of the crystal resonator 106 for arranging the ejection head 103 at the position where the droplet is ejected at (x, y) are calculated. Then, the position calculation unit 142 sends the calculated movement amount data to the control unit 101 (step 4).
[0044]
Next, in the measuring unit 107, the oscillating voltage generator 111 applies the oscillating voltage to the electrode 110a of the crystal resonator 106 while sweeping the frequency (step S5). The measurement unit 112 detects a current flowing through the electrode 110b of the crystal resonator 106 to detect a change in impedance, calculates a resonance frequency fbefore before the droplets adhere to the electrode 110b of the crystal resonator 106, and performs an operation. The data is output to the unit 113 (step S6). Note that the resonance frequency fbefore before the droplets adhere to the electrode 110b may be stored in advance in the calculation unit 113 without being measured each time.
[0045]
Next, the control unit 101 controls the head carriage 102 based on the movement amount data sent from the position calculation unit 142 to convey the ejection head 103 in the main scanning direction (X-axis direction) (step S7). . Similarly, the control unit 101 controls the sensor carriage 143 based on the movement amount data sent from the position calculation unit 142 to transport the crystal unit 106 in the sub-scanning direction (Y-axis direction) (step S8). . As a result, by relatively moving the ejection head 103 and the crystal resonator 106, the ejection head 103 can be disposed at a position where the droplet is ejected at a predetermined position (x, y) of the electrode 110b.
[0046]
If either one of the ejection head 103 and the crystal resonator 106 can move in both the main scanning direction and the sub-scanning direction, only one of the ejection head 103 and the crystal resonator 106 is moved. The ejection head 103 can be disposed at a position where the droplet is ejected at a predetermined position (x, y) of the electrode 110b.
[0047]
Subsequently, the control unit 101 supplies a drive signal to the piezoelectric element 122 included in the discharge head 103 according to the standard drive waveform, and discharges droplets from the discharge head 103 toward a predetermined position of the electrode 110b (Step S9). ). As a result, the droplet adheres to an exact predetermined position of the electrode 110b.
[0048]
Thereafter, the control unit 101 controls the head carriage 102 to convey the ejection head 103 to the standby position (step S10).
[0049]
Thereafter, in the measurement unit 107, the vibration voltage generation unit 111 applies the vibration voltage to the electrode 110a of the crystal resonator 106 while sweeping the frequency (step S11). The measurement unit 112 detects a current flowing through the electrode 110b of the crystal resonator 106 to detect a change in impedance, and the resonance frequency after the droplet adheres to the electrode 110b of the crystal resonator 106 and the resonance at that time. The resistance R is calculated and output to the calculation unit 113 (step S12).
[0050]
The calculation unit 113 calculates the resonance frequency change amount Δfreq = fbefore−fafter based on the resonance frequencies f before and after, and calculates the weight Im of the liquid droplet using the above-described equation (1) ( Step S13). Further, the calculation unit 113 calculates the viscosity η of the droplet using the above-described equation (2) based on the resonance resistance R. The calculation unit 113 outputs the calculated droplet weight Im and viscosity η to the control unit 101. The control unit 101 displays the calculated droplet weight Im and droplet viscosity η on the display unit 108 (step S14). The droplet weight is measured as described above.
[0051]
According to the droplet discharge device 100 of the first embodiment, the position indexing unit 140 can determine a predetermined position on the electrode 110b where the droplet should be attached. Further, the movement amount of at least one of the ejection head 103 and the crystal resonator 106 is calculated based on the determined predetermined position data, and at least one of the ejection head 103 and the crystal resonator 106 is calculated according to the calculation result. Move one.
As a result, the ejection head 103 is disposed at a position where the droplet is ejected at a predetermined position on the electrode 110b, and the droplet can be attached to the predetermined position of the electrode 110b. Therefore, the variation in the adhesion position of the droplet on the electrode 110b is improved. In addition, variations in the attachment position of the droplets on the electrode 110b due to variations in manufacturing of the crystal unit 106 and assembly in the apparatus 100 are also eliminated. Accordingly, it is possible to perform highly accurate and stable droplet weight measurement.
[0052]
Further, since the position indexing unit 140 includes the imaging unit 141 and the position calculating unit 142, alignment of the electrode 110b with respect to a predetermined position can be easily performed.
[0053]
In addition, when the droplet is attached on the center of gravity of the electrode 110b, the resonance frequency of the crystal unit 106 is the lowest compared to the case where the droplet is attached to a position other than the center of gravity of the electrode 110b. . That is, when the droplet is attached to the center of gravity of the electrode 110b, the amount of change in the resonance frequency before and after the attachment of the droplet is maximized. In this way, the most accurate and reliable weight measurement of the droplet can be performed by attaching the droplet on the center of gravity of the electrode having the highest sensitivity. For example, in the case of the circular electrode 110b, the sensitivity is best on the center point of the electrode, which is the center of gravity, and therefore the most accurate and reliable by setting the circular center of gravity (center point) as a predetermined position. It is possible to perform highly accurate droplet weight measurement.
In general, the droplets ejected from the ejection head may bend unexpectedly due to the surrounding environment, dead weight, and the like, and as a result, the droplet attachment position may deviate from the initial aim. On the other hand, in this embodiment, the predetermined position is set on the center of gravity of the electrode 110b, and the discharge head 103 is disposed at the position where the droplet is discharged at the predetermined position of the electrode 110b. Even if a flight bend occurs in the droplet ejected from 103 and the attachment position shifts, the amount of deviation from the center of gravity can be suppressed to a relatively small amount (the attachment position stays in the vicinity of the center of gravity). . Thereby, almost accurate droplet weight measurement can be realized.
[0054]
(Embodiment 2)
FIG. 12 is a perspective view illustrating the configuration of a liquid crystal display device mounted with a color filter, which is an electro-optical device, manufactured using the droplet discharge device according to Embodiment 2 of the present invention.
The liquid crystal display device 200 according to the second embodiment is equipped with accessory elements such as a liquid crystal driving IC (not shown), wirings (not shown), a light source 280, a support (not shown), and the like. The configuration of the liquid crystal display device 200 will be briefly described.
The liquid crystal display device 200 includes a color filter 210, a glass substrate 230, a liquid crystal layer (not shown) sandwiched therebetween, a polarizing plate 240 attached to the upper surface side of the color filter 210, and a glass substrate 230. And a polarizing plate (not shown) attached to the lower surface side of the main body. The color filter 210 includes a substrate 211 made of transparent glass. On the lower side of the substrate 211, a partition wall 212 made of a black photosensitive resin film, a colored portion 213, and an overcoat layer 214 are sequentially formed. An electrode 220 for driving liquid crystal is formed below the layer 214. In an actual liquid crystal display device, alignment films are provided on the liquid crystal layer side of the electrode 220 and the liquid crystal layer side of the pixel electrode 260 (not shown).
The liquid crystal driving electrode 220 formed on the liquid crystal layer side of the color filter 210 is formed by forming a transparent conductive material such as ITO (Indium Tin Oxide) on the entire surface of the overcoat layer 214.
[0055]
Scan lines 270 and signal lines 271 are formed in a matrix on the insulating layer 250 formed over the glass substrate 230, and a pixel electrode 260 is provided for each region surrounded by the scan lines 270 and the signal lines 271. It is done. A TFT (Thin Film Transistor) as a switching element is incorporated in a corner portion of each pixel electrode 260 and a portion between the scanning line 270 and the signal line 271, and a TFT is applied by applying a signal to the scanning line 270 and the signal line 271. Is turned on or off, and the current supply to the pixel electrode 260 is controlled.
[0056]
In addition to the color filter 210 of the second embodiment, if the droplet discharge device 100 of the present invention is used, a metal wiring material, a microlens array material, a photoresist material, an electroluminescence material, and a biological material Various liquid materials such as can be discharged and formed on the substrate W with an accurate droplet weight. Therefore, by using the droplet discharge device 100 of the present invention, it is possible to manufacture various electro-optical devices with high quality.
[0057]
(Embodiment 3)
FIG. 13 is a perspective view illustrating the configuration of a mobile phone as an example of an electronic apparatus including a liquid crystal display device that is an electro-optical device according to Embodiment 3 of the invention. The mobile phone 300 is provided with the above-described liquid crystal display device 200 in addition to the plurality of operation switches 310 as well as the earpiece 311 and the mouthpiece 312.
[0058]
In addition to the mobile phone 300, electro-optical devices manufactured using the droplet discharge device of the present invention include computers, projectors, digital cameras, movie cameras, PDAs (Personal Digital Assistants), in-vehicle devices, copiers, It can be used as a display unit of various electronic devices such as audio devices.
[0059]
Note that the present invention is not limited to the above-described first to third embodiments, and can be implemented by appropriately modifying it without changing the gist of the invention.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an entire droplet discharge device according to a first embodiment of the present invention.
FIG. 2 is a detailed configuration diagram of an ejection head.
FIG. 3 is a plan view showing a configuration of a QCM sensor.
FIG. 4 is an equivalent circuit diagram of a crystal resonator.
FIG. 5 is a conceptual diagram of a measurement unit.
FIG. 6 is a conceptual diagram of a feedback self-oscillation method.
FIG. 7 is an admittance diagram of a crystal resonator.
FIG. 8 is an explanatory diagram in which the ratio of a droplet weight measurement value at a measurement point of a droplet adhesion position is described on an electrode.
FIG. 9 is an explanatory diagram approximating a distance between a droplet adhesion position from an electrode center and a ratio of a measured value of a droplet weight by a curve.
FIG. 10 is a view showing an example of a predetermined position where a droplet is attached according to the shape of the electrode according to the first embodiment of the present invention.
FIG. 11 is an exemplary diagram of a droplet weight measurement flow of the droplet discharge device according to the first embodiment of the present invention.
FIG. 12 is an exemplary view of a liquid crystal display device according to a second embodiment of the present invention.
FIG. 13 is an exemplary diagram of a mobile phone including a liquid crystal display device according to a third embodiment of the present invention.
[Explanation of symbols]
100 .... Droplet discharge device, 101 ... Control unit, 102 ... Head carriage, 103R, 103G, 103B ... Discharge head, 104R, 104G, 104B ... Ink tank, 105 ... Stage, 106 ... Quartz vibration Child 107, Measurement unit 108 Display, 110, Crystal 110a, 110b Electrode 111, Vibration voltage generator 112, Measurement unit 113, Calculation unit 140, Position Indexing unit, 141... Imaging unit, 142.. Position calculation unit, 143 .. Sensor carriage, 200 .. Liquid crystal display device, 300.

Claims (6)

In a droplet discharge device that discharges droplets from a discharge head and draws on a drawing object,
Detection means comprising a piezoelectric vibrator having electrodes on both sides;
Position indexing means for indexing a predetermined position on the electrode where a droplet should be attached and calculating a movement amount for moving at least one of the ejection head or the piezoelectric vibrator to the indexed predetermined position When,
A moving means for moving at least one of the ejection head or the piezoelectric vibrator to the indexed predetermined position based on the amount of movement;
Oscillating means for applying a vibration voltage to the electrode to vibrate the piezoelectric vibrator;
A change in the resonance frequency of the piezoelectric vibrator before and after the droplet discharged from the discharge head adheres to the electrode is detected, and the change is made to the electrode based on the detected change in the resonance frequency of the piezoelectric vibrator. A drop weight measuring means for measuring the weight of the dropped drop;
A droplet discharge apparatus comprising: The liquid droplet ejection apparatus according to claim 1, wherein the position indexing unit indexes the predetermined position based on imaging data obtained by imaging the electrode. The droplet discharge device according to claim 1, wherein the predetermined position is a center of gravity of the electrode. An electro-optical device manufacturing method using the droplet discharge device according to any one of claims 1 to 3. An electro-optical device manufactured using the manufacturing method according to claim 4. An electronic apparatus comprising the electro-optical device according to claim 5.

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