JP4082181B2 - Pattern formation method - Google Patents

Description

【００６７】
（式１）において、ｐは圧力、μは流体の粘性係数、ｈは対向面間の隙間、ｒは半径方向位置、ｔは時間である。また、右辺が、隙間ｈが変化するときに発生するスクイーズアクション効果をもたらす項である。図６に、スクイーズポンプ部の寸法関係を示す。ｈ＝ｄｈ／ｄｔ として、（式１）の両辺を積分する。圧力と流量の境界条件から未定定数Ｃ₁，Ｃ₂を求める詳細な手順は省略するが、半径方向位置ｒの圧力は、
【００６８】
【数５】

【００６９】
但し、
【００７０】
【数６】

【００７１】
式３）において、Ｒ_sはねじ溝ポンプの内部抵抗、Ｐ_S0は供給源圧力であり、ねじ溝ポンプ（流体補給手段）の最大発生圧力Ｐ_maxと、材料をねじ溝に供給するためのエアーによる補助圧力Ｐ_supの和（Ｐ_S0＝Ｐ_sup＋Ｐ_max）である。
【００７２】
吐出ノズルの開口部：ｒ＝ｒ_i（図１の１５）において、Ｐ_i＝Ａ＋ＢＱ_iとする。吐出ノズルの流体抵抗をＲ_nとすれば、吐出ノズルを通過する流量はＱ_n＝Ｐ_i／Ｒ_nである。流れの連続性からＱ_i＝Ｑ_nであり、吐出ノズルの開口部の圧力Ｐ_iが次のように求まる。Ａ_i，Ｂ_iは（式２）におけるｒ＝ｒ_iのときのＡ，Ｂの値である。
【００７３】
【数７】

【００７４】
上式において、Ｒ_nは吐出ノズル抵抗、Ｒ_pはピストン端面とその対抗面間のスラスト流体抵抗である。ここで、第１次スクイーズ圧力Ｐ_squ1、第２次スクイーズ圧力Ｐ_squ2を次のように定義する。
【００７５】
【数８】

【００７６】
第１次スクイーズ圧力Ｐ_squ1は、ピストン端面とその相対移動面間の隙間を急峻に変化させることにより、ピストン端面間に発生する公知のスクイーズ効果によるもので、隙間ｈが狭い程、大きな圧力が発生する。
【００７７】
第２次スクイーズ圧力Ｐ_squ2を発生させる方法、及びこの作用を連続塗布の吐出遮断及び吐出開放に応用する方法は本発明が見出したもので、その原理は次のようである。ピストン端面とその相対移動面間の隙間を急峻に変化させることにより、ピストンの端面と流体供給源の間に流量変動が発生する。この流量変動は上記隙間を変化させた場合の容積変化に相当する。例えば、ピストン上昇により容積が増加した場合、ねじ溝ポンプの供給できる最大流量が容積変化以下ならば、ピストン端面に負圧が発生する。
【００７８】
（式４）、（式５）から、吐出ノズルの開口部の圧力Ｐ_iは、
【００７９】
【数９】

【００８０】
流量Ｑ_iは吐出ノズル抵抗をＲ_nとすれば、Ｑ_i＝Ｐ_i／Ｒ_nである。
吐出ノズルのノズル半径をｒ_n、ノズル長さをｌ_nとおくと、吐出ノズル抵抗は、
【００８１】
【数１０】

【００８２】
また、Ｒ_pは前述したように、吐出ノズル上流側（図１の１５）とピストン外周部（図１のポンプ室端部１３）の間のスラスト流体抵抗である。Ｒ_sは、前述したように、ピストン端面の外周部１３と供給源側（吸入口）の間の流路の流体抵抗（ねじ溝ポンプの場合は内部抵抗）である。
【００８３】
【数１１】

【００８４】
（２）流体遮断・開放時の圧力特性
以下、吐出ノズル上流側（図１の１５）の圧力を求める計算を、［ｉ］流体補給手段の内部抵抗Ｒ_sは無視できる程小さい場合、［ii］本発明に相当し、流体補給手段に内部抵抗Ｒ_sを有する場合、の２ケースに分けて行なう。
【００８５】
図７は、上記［ｉ］［ii］の計算を行なう上で共通のピストンの変位曲線であり、振幅Δｈ＝１０μｍは一定で、最小隙間ｈ_minを各種変えた場合を示す。表１に解析条件を示す。
【００８６】
［ｉ］流体補給手段の内部抵抗Ｒ_sは無視できる程小さい場合
この場合、（式５）においてＰ_squ2→0であり、圧力発生源は第１次スクイーズ圧力Ｐ_squ1だけである。流体補給手段にねじ溝式のようなポンプを用いず、エアー圧で材料を供給する場合と等価である。ねじ溝ポンプを用いた場合でも、その内部抵抗が小さければ等価になる。
【００８７】
圧力発生源と負荷抵抗の関係を電気回路モデルで表すと、図８のようになる。図８において、Ｐ_maxは流体補給手段（ねじ溝式）の最大発生圧力、Ｒ_nは吐出ノズルの固定抵抗、Ｒ_pはスラスト端面の半径方向の可変流体抵抗であり、隙間ｈの大きさで変わる。図９は、図７のピストン変位曲線を与えたときの吐出ノズル開口部の圧力Ｐ_iを求めたものである。吐出開放時０．０２＜ｔ＜０．０３秒の区間で、スクイーズ効果による正のピーク圧が発生し、吐出遮断時０．０７＜ｔ＜０．０８秒の区間で、逆スクイーズ効果による負のピーク圧が発生する。
【００８８】
０＜ｔ＜０．０２秒の区間をＡ，０．０３＜ｔ＜０．０７秒の区間をＢ，ｔ＞０．０８秒の区間をＣとする。区間Ｂの圧力が区間Ａ，Ｃと比べて低下するのは、区間Ｂではスラスト抵抗Ｒ_pが増加するからである。
【００８９】
隙間ｈの最小値ｈ_minが増大すると、▲１▼区間Ａ，Ｂ，Ｃの圧力が上昇する、▲２▼スクイーズ圧力の振幅が低下する。上記▲１▼▲２▼の理由により、最小隙間ｈ_min＞３０μｍとなると、吐出遮断時０．０７＜ｔ＜０．０８秒の区間で、負のピーク圧の最小値はＰ_min＜０にはならない。すなわち最小隙間ｈ_min＞３０μｍとなると、吐出遮断はできない。
【００９０】
［ii］流体補給手段に十分に大きな内部抵抗Ｒ_sを有する場合（本発明）
この場合、流体補給手段に例えばねじ溝ポンプを用いて、かつ、ねじ溝ポンプの内部抵抗Ｒ_sを十分に大きくした場合に相当する。図１０は等価電気回路モデルである。
【００９１】
図１１は、図１０のピストンの変位曲線を与えたときの吐出ノズル上流側の圧力Ｐ_iを求めたものである。上記［ｉ］場合と比べて、区間Ａ，Ｂ，Ｃの圧力は大きく変化しない。吐出開放時０．０２＜ｔ＜０．０３秒の区間で、スクイーズ効果による正のピーク圧が発生し、吐出遮断時０．０７＜ｔ＜０．０８秒の区間で、逆スクイーズ効果による負のピーク圧が発生する点は、上記［ｉ］場合と同様である。
【００９２】
しかし、最小隙間を大きくすると、直感的な予想に反して、上記［ｉ］場合と逆に、ピーク圧の絶対値Ｐ_imaxは増大するという驚くべき結果が得られる。この理由を図１０の等価電気回路モデルを用いて説明すると、次のようである。
【００９３】
最小隙間ｈ_minが増大すると、第１次スクイーズ圧力Ｐ_squ1→０となるが、同時にピストン端面とその対向面のスラスト流体抵抗Ｒ_p→０となるため、分圧比（＝Ｒ_n／（Ｒ_s＋Ｒ_p＋Ｒ_n）が増大する。Ｐ_squ1→０となる影響よりも、上記分圧比が増大する影響の方が大きい場合は、ｈ_minが大きくなると圧力Ｐ_iの振幅は増大する。但し、本実施形態では最小隙間ｈ_min＝５０μｍに近づくと圧力上昇の度合いは低下していく。
【００９４】
（２）遮断性能評価
さて、塗布開始時の始点については、吐出ノズル先端の流体の表面張力に打ち勝ちと共に、始点での塗布線の「太り」にならない範囲で、オーバーシュート圧力（正のスクイーズ圧力のピーク値）の大きさを設定すればよい。そのためには、ピストン変位曲線の立ち上がり区間の長さ（図７ではΔｔ＝０．０２秒に設定）を調節すればよい。Δｔを短くすれば、オーバーシュート圧力は高くなり、Δｔを長くすれば、オーバーシュート圧力は低くなり圧力波形は鈍化する。
【００９５】
塗布開始時の終点については、通常はできるだけ切れ味よく遮断できる方がよい。この切れ味の良さ、すなわち、ディスペンサーの遮断性能を評価するために、遮断時（吐出流量Ｑ_i＜０）における吐出遮断時の総逆流量Ｑ_sを求める。
【００９６】
【数１２】

【００９７】
積分範囲のｔ₁とｔ₂は、吐出流量Ｑ_i＜０となる開始時と終了時の時間である。前述したように、遮断時の実際の圧力は絶対圧０気圧以下にはならないため、（式９）から得られる値は実際の逆流量ではない。しかし、様々な条件下での「遮断性能」を相対比較する上で上式は有用である。
【００９８】
図１２は、ピストン端面の最小隙間ｈ_minに対する吐出遮断時の総逆流量Ｑ_sを（式９）を用いて求めたものである。以下、ポンプの内部抵抗Ｒ_s＝０の場合と、Ｒ_s＝０．０５の場合について注目する。
【００９９】
ポンプの内部抵抗Ｒ_s＝０の場合、最小隙間ｈ_minが大きくなると、総逆流量Ｑ_sは低下していく。最小隙間ｈ_min＞３０μｍとなると、逆流は発生せず完全な吐出遮断はできない。
【０１００】
内部抵抗Ｒ_s＝０．０５の場合、最小隙間ｈ_minが大きくなると、総逆流量Ｑ_sは増大していくが、ｈ_min＝ｈ_x1（≒４０μｍ）近傍を超えると、総逆流量Ｑ_sはｈ_minに依存せず一定値を保つようになる。
【０１０１】
ここでｈ_x1を次のように定義する。総逆流量Ｑ_sが隙間の影響を強く受ける前記隙間の最小値の設定範囲を０＜ｈ_min＜ｈ_x1、総逆流量Ｑ_sが前記隙間の変化に対して鈍感なｈ_minの設定範囲をｈ_min＞ｈ_x1とする。ｈ_x1は０＜ｈ_min＜ｈ_x1の領域におけるｈ_minに対する曲線Ｑ_sの包絡線と、ｈ_min→∞におけるＱ_s＝Ｑ_seの交点である。
【０１０２】
以下、完全な吐出遮断ができる条件について補足する。
【０１０３】
最小隙間ｈ_minが０＜ｈ_min＜ｈ_x1の領域、或いは、ｈ_min≒ｈ_x1近傍にある場合は、（式４）における圧力Ｐ_iが、吐出遮断時（隙間ｈの時間微分が最大値をとるとき）に負になれば良い。すなわち、前記隙間ｈの時間微分が最大値をもつときの第１次スクイーズ圧力Ｐ_squ1＝Ｐ_squ10、第２次スクイーズ圧力Ｐ_squ2＝Ｐ_squ20としたとき、Ｐ_S0＋Ｐ_squ10＋Ｐ_squ20＜０となれば良い。
【０１０４】
最小隙間ｈ_minがｈ_min≫ｈ_x1の領域にある場合は、（式４）において、ｈ→∞とすると、第１次スクイーズ圧力Ｐ_squ1→０，Ｒ_p→０となるため次式が得られる。但し、Ｐ_s0≒Ｐ_max，Ｒ_s＝Ｐ_max／Ｑ_maxとする。
【０１０５】
【数１３】

【０１０６】
（式９）の第２項は、ピストン端面８とその対向面９で形成されるピストン端面部１４の幾何学的な容積変化分に相当する。吐出遮断時において、時間微分の最大値をＶ_max、流体補給手段の最大流量をＱ_maxとしたとき、
【０１０７】
【数１４】

【０１０８】
が満たされれば、圧力Ｐ_iは負圧になるため、吐出は遮断される。
【０１０９】
図１２のグラフにおいて、内部抵抗Ｒ_sが小さくなると、総逆流量の収束値Ｑ_s→Ｑ_seの大きさは低下していく。しかし、いずれの条件下でも、最小隙間ｈ_min＞ｈ_x1の領域では総逆流量Ｑ_sはｈ_minに依存せず一定値を保つ点は変わりない。すなわち、最小隙間ｈ_min＞ｈ_x1に設定すれば、内部抵抗Ｒ_sの大きさにかかわらず、遮断性能が隙間の影響を受けず、後述するように定常時の流量も隙間の変動を受けないという点で、本発明の特徴を活かすことができる。
【０１１０】
図１３はピストン端面の最小隙間ｈ_minに対する吐出時の吐出ノズル上流側圧力Ｐ_iを求めたものである。ｈ_x2を同様に次のように定義する。圧力Ｐ_iが隙間の影響を強く受ける前記隙間の最小値の設定範囲を０＜ｈ_min＜ｈ_x2，圧力Ｐ_iが前記隙間の変化に対して鈍感なｈ_minの設定範囲をｈ_min＞ｈ_x2とする。ｈ_x2は０＜ｈ_min＜ｈ_x2の領域におけるｈ_minに対する曲線Ｐ_iの包絡線と、ｈ_min→∞におけるＰ_i＝Ｐ_ieの交点である。
【０１１１】
最小隙間ｈ_minが大きくなると、圧力Ｐ_iは増大していくが、ｈ_min＝ｈ_x2（≒４０μｍ）近傍を超えると、圧力Ｐ_iはｈ_minに依存せず一定値を保つようになる。つまり、ｈ₀＞ｈ_x2に設定すれば、部材の熱膨張、部品の加工精度と組み立て精度のばらつきなどにより、ピストン端面位置が多少増減しても、圧力Ｐ_i（すなわち吐出流量Ｑ_n＝Ｐ_i／Ｒ_n）は不変である。ｈ_x2値は（式４）を用いて解析的に求めてもよいが、ピストン位置を変えて流量を実測して求めてもよい。このとき、Ｑ_ne＝Ｐ_ie／Ｒ_nである。
【０１１２】
図１２と図１３のグラフを比較すればわかるように、ｈ_x1≒ｈ_x2であり、ｈ_x2が求まれば、ｈ_x1の大きさを推定することができる。
【０１１３】
図１４はピストン吐出側端面の流体抵抗Ｒ_pと最小隙間ｈ_minの関係を求めたものである。最小隙間ｈ_minが増大すると、流体抵抗Ｒ_pは大幅に低下する。隙間に対するＲ_pの特性は、第一のスクイーズ圧力のみを利用する遮断性能（ポンプの内部抵抗Ｒ_s＝０の場合）とほぼ同一の傾向を示す。
【０１１４】
すなわち、ポンプの内部抵抗Ｒ_sがピストン吐出側端面の流体抵抗Ｒ_pよりも十分大きくなる最小隙間ｈ_minの領域が、本実施例のヘッドの駆動条件である。
【０１１５】
以上、総逆流量Ｑ_s、吐出ノズル上流側圧力Ｐ_i（或いは流量Ｑ_n）、スラスト流体抵抗Ｒ_pをピストン端面の最小隙間ｈ_minとの関係で整理した。この最小隙間ｈ_minを用いる代わりに、例えば、ピストン変位の最大値、平均値、振幅の中心値等を代表値ｈ₀として用いてもよい。
【０１１６】
【表１】

【０１１７】
［３］ 具体的な実施の形態
以下、本発明をＰＤＰの蛍光体層形成方法および形成装置に適用した実施形態について、図１５の概略斜視図を用いて説明する。
【０１１８】
図１５において、３５０はパネルを載置するための載置台である。載置台３５０の両側を挟んで一対のＹ軸方向搬送装置３５１，３５２が設けられている。また、Ｘ軸方向搬送装置３５３が、Ｙ−Ｙ’方向に移動可能に、前記Ｙ軸方向搬送装置上に搭載されている。更に、Ｚ軸方向搬送装置３５４が、矢印Ｘ−Ｘ’方向に移動可能に、前記Ｘ軸方向搬送装置上に搭載されている。Ｚ軸方向搬送装置３５４には、ディスペンサー３５５を離脱可能に装着したシリンジ装着部３５６が、Ｚ−Ｚ’方向に移動可能に搭載されている。
【０１１９】
Ｙ軸方向搬送装置３５１、３５２は、Ｙ軸モータ３５７ａ、３５７ｂによってＸ軸方向搬送装置３５３を搬送する。また、Ｘ軸方向搬送装置３５３は、Ｘ軸用モータ３５８によってＺ軸方向搬送装置３５４を搬送する。また、Ｚ軸方向搬送装置３５４は、Ｚ軸用モータ（図示せず）によってシリンジ装着部３５６を搬送する。
【０１２０】
上記装置によって、ＰＤＰ用の基板に蛍光層が形成される。まず、赤色（Ｒ）蛍光体層形成用のペースト状蛍光体を収容したシリンジ３５９をディスペンサー３５５に装着する。図２２に示すように、ＰＤＰ基板は蛍光体層を形成する有効表示領域３６０ａと、この有効表示領域の外周部に蛍光体層を形成しない非有効表示領域３６０ｂを有する（基板３６１は図１５では図示せず）。
【０１２１】
この基板３６１を載置台３５０の所定位置に載置して固定する。例えば、４２インチのＰＤＰ用基板の場合、厚さ３．０ｍｍのガラス板からなる基板３６１の有効表示領域３６０ａには、予め矢印Ｘ−Ｘ’方向に平行に長さＬ＝５６０ｍｍ，高さＨ＝１００μｍ，幅Ｗ＝５０μｍのリブ（光吸収層）が、ピッチＰの間隔を保って、１９２１本形成されている。この１９２１本のリブによって１９２０本の溝が形成されているので、ＲＧＢ蛍光体は、それぞれ６４０本（＝１９２０本／３）の溝に塗布されることになる。
【０１２２】
最初に、ディスペンサー３５５をＲ蛍光体塗布開始位置まで移動し、Ｚ軸用モータにより、吐出ノズル３４９の先端を所定の高さに位置決めする。
【０１２３】
次に、吐出ノズル３４９からＲ蛍光体の吐出を開始すると同時に、矢印Ｘ方向へ移動して蛍光体塗布を開始する。吐出ノズル３４９が一本のリブの長さＬ（図２２）だけ塗布線を描き、吐出ノズル３４９先端が有効表示領域３６０ａから非有効表示領域３６０ｂに入ると、蛍光体の吐出は停止する。
【０１２４】
更に、吐出ノズル３４９は蛍光体の吐出を停止したままで、３Ｐだけ矢印Ｙ方向へ移動する。再び、吐出ノズル３４９からＲ蛍光体の吐出を開始すると同時に、矢印Ｘ’方向へ移動して蛍光体塗布を再開する。上記ステップを繰り返し、塗布本数が６４０本になると、Ｒ蛍光体による作業は終了する。
【０１２５】
以上が蛍光体塗布の基本ステップであるが、残されたＧ蛍光体、Ｂ蛍光体の塗布については、別途設置されたＧ蛍光体、Ｂ蛍光体専用載置台にパネルを順次移送してもよい。或いは、同一の載置台に、３種類（ＲＧＢ蛍光体塗布用）のディスペンサーをそれぞれ配置してもよい。
【０１２６】
なお、吐出ノズルの始終端の位置と、塗布開始・終了のタイミング、及び、ステージの速度と同期した塗布量の制御はあらかじめプログラミングされた始端と終端位置情報、及びステージからの変位・速度情報に基づいて行われる。このようにして、リブ間の溝の内面形状に沿ったＲＧＢの蛍光体層の形成作業がすべて終了すると、ディスペンサーの吐出ノズル先端位置は、ホームポジションに復帰する。以上スクリーンストライブの塗布工程が終了すると、基板を搬送後、蛍光体の乾燥工程へ移行する。
【０１２７】
以下、本発明の蛍光体層形成方法および形成装置に適用したディスペンサーの第１の実施形態について、図１６を用いて説明する。
【０１２８】
以下に示す本実施形態のディスペンサーは、ピストンとこのピストンを収納するスリーブの間に、相対的な回転運動と直線運動を同時に与える「２自由度アクチュエータ」を有する。すなわち、
▲１▼第１のアクチュエータでピストンを直線駆動することにより、ピストンの吐出側端面に正負のスクイーズ圧力を発生させる。
【０１２９】
▲２▼回転運動を与える第２のアクチュエータで、ねじ溝が形成されたピストンを回転させてポンピング圧力を発生させ、塗布流体を吐出側に圧送する。
上記▲１▼▲２▼の組み合わせにより、有効表示領域と非有効表示領域の境界部における塗布線の高速遮断・高速開放の制御を実現したものである。
【０１３０】
図１６において、１０１は第１のアクチェータであり、本実施形態では、高い位置決め精度が得られ、高い応答性を持つと共に大きな発生荷重が得られる超磁歪素子を用いている。１０２は第１のアクチェータ１０１によって駆動される主軸（ピストン）である。前記第１のアクチェータは、ハウジング１０３に収納されており、このハウジング１０３の下端部（フロント側）に、主軸１０２を収納するポンプ部１０４が装着されている。
【０１３１】
１０５は第２のアクチェータであり、主軸１０２とハウジング１０３の間に相対的な回転運動を与えるものである。モータロータ１０６は上部主軸１０７に固着され、また、モータステータ１０８は上部ハウジング１０９に収納されている。１１１，１１２は超磁歪素子から構成される円筒形状のリア側超磁歪ロッド及びフロント側超磁歪ロッドである。１１３は超磁歪ロッド１１１，１１２の長手方向に磁界を与えるための磁界コイルである。１１４，１１５，１１６は超磁歪ロッド１１１，１１２にバイアス磁界を与えるためのリア側，中間部，フロント側の永久磁石である。リア側とフロント側の永久磁石１１４，１１６が、超磁歪ロッド１１１，１１２と中間部永久磁石１１５を矜持する形で配置されている。この永久磁石１１４〜１１６は、超磁歪ロッド１１１，１１２に予め磁界をかけて磁界の動作点を高めるもので、この磁気バイアスにより磁界の強さに対する超磁歪の線形性が改善できる。
【０１３２】
１１７は超磁歪ロッド１１１のリア側に配置され、磁気回路のヨーク材であるリア側ヨーク、１１８は超磁歪ロッド１１２のフロント側に配置され、ヨーク材を兼ねたフロント側スリーブ、１１９は磁界コイル１３の外周部に配置された円筒形状のヨーク材である。
【０１３３】
１１２→１１５→１１１→１１４→１１７→１１９→１１８→１１６→１１２により、超磁歪ロッド１１１，１１２の伸縮を制御する閉ループ磁気回路を形成している。なお、主軸１０２はこの磁気回路に影響を与えないように、非磁性材料を用いている。すなわち、超磁歪ロッド１１１，１１２、磁界コイル１１３、永久磁石１１４〜１１６、リア側ヨーク１１７，フロント側スリーブ１１８，ヨーク材１１９により、磁界コイルに与える電流で超磁歪ロッドの軸方向の伸縮を制御できる超磁歪アクチェータ（第１のアクチェータ１０１）を構成している。
【０１３４】
１２０は上部主軸１０７を回転自在、かつ、軸方向に移動可能に収納するリア側スリーブである。このリア側スリーブ１２０もまた軸受１３９により、中間ハウジング１２１に対して回転自在に支持されている。
【０１３５】
１２２はリア側ヨーク１１７とリア側スリーブ１２０の間に装着されたバイアスバネである。このバイアスバネ１２２から加わる軸方向荷重により、超磁歪ロッド１１１，１１２はバイアス永久磁石１１４〜１１６を介在して、上下のリア側ヨーク１７，フロント側スリーブ１８に押圧される形で把持されている。この結果、超磁歪ロッド１１１，１１２には常に軸方向に圧縮応力が加わるため、繰り返し応力が発生した場合に、引っ張り応力に弱い超磁歪素子の欠点が解消される。
【０１３６】
フロント側スリーブ１１８は主軸１０２を軸方向移動可能に収納している。モータ１０５から伝達された主軸１０２の回転動力は、主軸１０２、フロント側スリーブ１１８の間に設けられた回転伝達キー１２３によってフロント側スリーブ１１８に伝達される。またフロント側スリーブ１１８も軸受１２４によって、ハウジング１０３に回転自在に支持されている。
【０１３７】
上記構成により、モータ１０５の回転動力は主軸１０２とフロント側スリーブ１１８のみに伝達され、脆性材料である超磁歪素子に捻りトルクは発生しない。
【０１３８】
また、リング状に形成された超磁歪素子１１１，１１２と永久磁石１１４〜１１６は、非磁性材料の主軸２を貫通する形で配置されている。また、主軸１０２の外周部と前記超磁歪ロッド及び前記永久磁石の内周部の間の隙間は十分に小さく設定している。その結果、装置の回転時に各部材に加わる遠心力の影響によって、前記超磁歪ロッド及び前記永久磁石の軸芯が大きくずれることはない。
【０１３９】
すなわち、各部材を貫通して設けられた主軸２は、脆性材料である超磁歪素子に対して圧縮応力以外は与えない「保護機能」と、回転時の「軸芯ズレの防止機能」を兼ねている。
【０１４０】
１２５は第２のアクチェータであるモータ１０５の上部に配置された上部主軸７の回転位置情報を検出するためのエンコーダである。また、１２６は上部主軸７（及び主軸１０２）の上端面１２７の軸方向変位を検出するための変位センサーである。
【０１４１】
上記構成により、回転運動と微少変位の直線運動の制御を同時に、かつ、独立して行うことができる「２自由度・複合動作アクチュエータ」が実現できる。更に、本実施形態では、第１のアクチェータに超磁歪素子を用いたために、超磁歪ロッド１１１，１１２（及び主軸１０２）を直線運動させるための動力を、外部から非接触で与えることができる。
【０１４２】
超磁歪素子に加えた入力電流と変位は比例するため、変位センサーなしのオープンループ制御でも、主軸１０２の軸方向位置決め制御は可能である。しかし、本実施形態のような位置検出手段を設けてフィードバック制御をすれば、超磁歪素子のヒステリシス特性も改善できるため、より高い精度の位置決めができる。
【０１４３】
さて、本実施形態では、主軸１０２の軸方向位置決め機能を用いて、主軸の定常回転状態を保ったままで、主軸の吐出側端面の隙間の大きさを任意に制御することができる。この機能を用いて、吸入口１３２から吐出ノズル１３３に至るいかなる流通路の区間も機械的に非接触の状態で、始終端における粉流体の遮断・開放の制御ができる。
【０１４４】
１２８は主軸２の外表面に形成された流体を吐出側に圧送するためのラジアル溝、１２９は流体シール、１３０はシリンダである。この主軸１０２とシリンダ１３０の間で、主軸１０２とシリンダ１３０の相対的な回転によってポンピング作用を得るためのポンプ室１３１（流体輸送室）を形成している。また、シリンダ１３０には、ポンプ室１３１と連絡する吸入孔１３２が形成されている。１３３はシリンダ１３０の下端部に装着された吐出ノズル、１３４はシリンダ１３０の吐出側端面に締結された吐出プレートである。１３５は主軸１０２の吐出側端面に装着されたスラストプレートである。
【０１４５】
流体圧送手段であるラジアル溝１２８は、スパイラルグルーブ動圧軸受として知られている公知のものであり、またねじ溝ポンプとしても利用されている。
【０１４６】
さて、本実施形態では、超磁歪素子で駆動される主軸１０２（以下「ピストン」と称す）が回転と同時に高速の直線運動ができることを利用して、次の方法で塗布線の始終端に係る課題の解決を図った。
【０１４７】
▲１▼塗布開始時には、ピストンを急速に降下させると同時にモータの回転を開始する。
【０１４８】
▲２▼塗布終了時には、ピストンを上昇させると同時にモータの回転を停止する。
【０１４９】
本実施形態では、ピストンを超磁歪素子で駆動しているため、ピストンの入力信号に対する出力変位の応答性は、１０^-3ｓｅｃ（１０００Ｈｅｒｚ）のオーダーであった。隙間の変化に対するスクイーズ圧力発生の間の時間遅れは僅少であるため、流量制御の応答性は極めて高い。
【０１５０】
本実施形態では、塗布線の始点・終点をスムーズに描かせるためのオーバーシュート圧力とサックバック圧力を、ピストンの軸方向運動によって得ることができた。本実施形態では、ピストン変位曲線（図７に一例を示す）は任意の形状を設定することができる。また、ピストンを駆動する超磁歪素子は高い応答性をもつために、変位曲線が急峻な変化をしても十分に追従できる。すなわち、超磁歪素子の変位・速度制御により、モータの回転数制御ではできない微妙な始終端の吐出圧力と流量の制御ができる。
【０１５１】
本実施形態では、超磁歪素子の軸方向変位の制御と、モータの回転数制御を組み合わせることにより、連続塗布線の始終端の課題を解決すると共に、Ｕターン区間において、吐出ノズルから材料のリークが無い完全遮断状態を任意の時間保つことができた。Ｕターン区間を十分に短く設定できる場合は、モータの回転を維持したままで、ピストンのみの駆動により終点での流量遮断と始点での開放ができる。
【０１５２】
図１６の本実施形態では、主軸（ピストン）１０２の軸方向位置を検出するために、変位センサー１２６を主軸１０２の上端に配置した。この変位センサー１２６の役割は、主軸１０２の吐出側端面とその対抗面の隙間（図１のｈに相当）を制御するためのものである。しかし変位の検出個所と主軸の吐出側端面の距離が長いため、部材の熱膨張が隙間に与える影響が懸念される。
【０１５３】
例えば、主軸上端と吐出側端面の距離をＬ＝２００ｍｍ、熱膨張係数α＝１３×１０^-6として、主軸とハウジング間の温度差がΔＴ１０℃生じた場合、吐出側端面とその対抗面の隙間ｈの変動分Δｈは、
【０１５４】
【数１５】

【０１５５】
上記Δｈは制御不可能なドリフト成分となる。
【０１５６】
しかし、流体補給手段が十分に大きな内部抵抗Ｒ_sを有して、かつ隙間ｈを十分に大きく（例えば、図１３において、ｈ_min＝１５０μｍ）設定すれば、隙間変動が連続吐出量と遮断性能の両方に影響を与えないヘッド構成が実現できる。
【０１５７】
本実施形態では、吐出遮断性能は第２次スクイーズ作用を利用しているため、隙間ｈの絶対値ではなく、隙間の微分の最大値Ｖ_maxで決まる。そのため、上記変位ドリフトの影響は受けない（式９）。
【０１５８】
本実施形態では、超磁歪素子を用いた２自由度アクチュエータにより、ピストンに軸方向移動と回転の両方の機能を与えてポンプ部を構成した。この構成の代わりに、例えば、軸方向に移動しない回転軸（外周側ピストン）を円筒形状として、この回転軸に中心軸（内周側ピストン）を挿入し、回転軸をモータで駆動し、中心軸を固定側に設置された電磁歪素子等で軸方向に駆動させる構成でもよい。この場合、内周側ピストンの吐出側端面とその対向面の隙間を増減させることにより、終点での流量遮断と始点での開放ができる。要は、流体輸送室の空間を増減できればよいのである。また、外周側ピストンとこの外周側ピストンを収納する固定側の相対移動面にねじ溝を形成すれば、実施例同様に流体圧送手段にできる（図示せず）。
【０１５９】
ディスプレイパネルの外周部（図２２の３６３）に障害物（例えばウオール）がある場合は、ディスペンサーの本体と障害物が接触しない範囲で、吐出ノズル１３３の全長を長くとればよい。吐出プレートにパイプを装着し、そのパイプ下端部に適切な内径と長さを持つ吐出ノズルのチップを装着すればよい。
【０１６０】
また、流体輸送手段であるねじ溝ポンプは、本発明を実施する上で必須条件では無い。外部に設置された圧力源（ポンプ）を利用して、流体をポンプ室１３１に供給してもよい。この場合はピストンにねじ溝は形成する必要は無い。例えば、流体圧送手段に外部に設置されたギヤポンプを利用して、かつ、Ｕターン区間を十分に短く設定できる場合は、ピストンのみの駆動により、始終点での流量遮断と開放の制御をすればよい。
【０１６１】
また、微少粒子が含まれた蛍光体、電極材料のような粉流体を塗布する場合は、ギャップδの最小値δ_minは微少粒子径φｄよりも大きく設定すればよい。
【０１６２】
【数１６】

【０１６３】
流体補給手段に、前述した粘性式のねじ溝ポンプを用いれば、流体供給源から吐出ノズルに至るまで、機械的な接触部を介在することない流路を構成することができるため、粉流体を輸送するのに有利となる。
【０１６４】
高粘度流体を吐出させる場合、ポンピング圧力、スクイーズ圧力共極めて大きな流体圧の発生が予想される。この場合、ピストンを駆動する第１のアクチェータには、高い流体圧に抗する大きな推力が要求されるため、数百〜数千Ｎの力が容易に出せる電磁歪型アクチェータの適用が効果的である。電磁歪素子は、数ＭＨｚ以上の周波数応答性を持っているため、主軸を高い応答性で直線運動させることができる。そのため、高粘度流体の吐出量を高いレスポンスで高精度に制御できる。
【０１６５】
また、軸方向駆動手段に超磁歪素子を用いた場合、圧電素子を用いる場合と比べて、伝導ブラシも省略できることから、モータ（回転手段）の負荷を軽減できると共に、全体構成が極めてシンプルとなるため、稼動部の慣性モーメントを極力小さくでき、ディスペンサーの細径化が可能である。
【０１６６】
なお、本実施形態ではピストンとその対向面の最小隙間は、ｈ_min＝１５０μｍに設定した。本実施形態の蛍光体の粒径はφｄ＝７〜９μｍであり、ｈ_min≫φｄであるため、吸入口から吐出口に至る通路で蛍光体の微粒子を機械的に圧搾・破損することはない。
【０１６７】
本発明をＰＤＰ表面板の電極形成に用いる場合、銀ペーストの粒子径は０．１〜１μｍであった。蛍光体の微粒子よりも粒子径は小さいが、比重の大きな電極材のポンプ内部での流動性向上に配慮を要する。この場合でも、ピストン部の最小隙間を、例えばｈ_min＞１５０μｍに形成できる本発明のヘッドは、目詰まり防止の信頼性の点で極めて有利である。ＰＤＰ表面板の場合、端子部とバス電極部の境界部で電極線の終端（或いは始端）を遮断せねばならないが、本実施形態で説明した蛍光体塗布と同様な方法を用いることができる。また、電極線の線幅が個所によって異なる場合、流体補給手段にねじ溝式を用いれば、流量は回転数に比例するため、線幅に合わせて回転数とステージ速度を設定すればよい。
【０１６８】
図１７は本発明の第２の実施形態を示し、流体補給手段であるねじ溝ポンプと、第１次スクイーズ圧力を発生させるピストンを分離して構成した場合を示す。５１は主軸であり、ハウジング５２に対して回転方向に移動可能に収納されている。主軸５１は回転伝達手段（矢印５３）により回転駆動される。５４は主軸５１とハウジング５２の相対移動面に形成されたねじ溝（黒く塗りつぶした部分）、５５は流体の吸入口である。
【０１６９】
５６はピストン５７を軸方向（矢印５８）に移動させる軸方向駆動手段、５９はピストン５７の端面、６０はその固定側対向面、６１はハウジング５２に装着された吐出ノズルである。ピストン端面５９と固定側対向面６０が隙間方向に相対移動する２面（吐出室）となる。６２は主軸端部、６３はピストン外周部、６４は主軸端部６２とピストン外周部６３を結ぶ流通路である。
【０１７０】
ピストン外周部６３には、流通路６４を経て、流体補給手段であるねじ溝ポンプ５４により常時塗布流体６５が供給される。軸方向駆動手段５６（具体構造は図示せず）は、ピストン５７と固定側であるハウジング５２の間に軸方向相対位置に変化を与える。この軸方向駆動手段５６によって、ピストン端面５９とその対向面６０間の隙間ｈを変化させる点は、図１６に記載された実施形態、或いは、図１のモデルと同様である。また、ねじ溝ポンプとピストンの構成条件も同様に、
▲１▼ ピストン端面の隙間ｈの最小値をｈ＝ｈ_minとしたとき、ｈ_minは十分に大きく、例えば、ｈ_min＞ｈ_x1（例えばｈ_x1≒４０μｍ）である。
【０１７１】
▲２▼ ねじ溝は定量ポンプに近い設計がなされており、その内部抵抗Ｒ_sは十分に大きい。
【０１７２】
第２の実施形態に示すように、流体補給手段であるポンプ部６６と、軸方向駆動手段によってピストンを駆動する部分（ピストン駆動部６７）を分離して塗布装置を構成すれば、適用する対象によっては装置のコンパクト化、簡素化が図れる。例えば、軸方向駆動手段に圧電素子を用いてピストン駆動部を構成れば、圧電素子アクチュエータの部分は充分にコンパクトにできるため、後述するマルチヘッドの場合、装置全体を大幅に簡素化できる。
【０１７３】
図１８の斜視図は本発明の第３の実施形態を示し、流体補給手段であるポンプ部とピストン駆動部をフレキシブルなチューブで連結する構成にして、ポンプ部を固定側に配置し、ピストン駆動部を高速走行するステージ側に配置したものである。この場合、ピストン駆動部は軽量でよいために、パネルに対する吐出ノズル先端の高速速度制御・位置決め制御に有利となる。
【０１７４】
図１８において、１５０はパネルであり、このパネルの両側を挟んで一対のＹ軸方向搬送装置１５１，１５２が設けられている。また、Ｘ軸方向搬送装置１５３が、Ｙ−Ｙ’方向に移動可能に、前記Ｙ軸方向搬送装置上に搭載されている。
【０１７５】
更に、Ｚ軸方向搬送装置１５４が、矢印Ｘ−Ｘ’方向に移動可能に、前記Ｘ軸方向搬送装置上に搭載されている。Ｚ軸方向搬送装置１５４には、圧電アクチュエータとピストンで構成されるピストン駆動部１５５が搭載されている。
【０１７６】
１５６は流体補給手段であるポンプ部であり、固定側に配置されている。１５７はこのポンプ部１５６とピストン駆動部１５５を繋ぐ流路であるフレキシブルチューブである。
【０１７７】
［４］その他の適用例 … マルチヘッドの場合
以上説明したディスペンサーの実施形態は、何れも流体補給手段であるポンプ部とピストン駆動部が一対で構成されたシングルヘッドであった。
【０１７８】
以下、本発明のヘッドをさらに生産タクトアップする方策について述べる。
【０１７９】
ディスペンサーを用いてパネル面に蛍光体層、銀ペースト電極材等を形成する場合でも、スクリーン印刷方式と同等の生産タクトが要望される。
【０１８０】
本発明を、例えばＰＤＰ背面板の蛍光体塗布、表面板の電極形成プロセスに適用する場合、前述した塗布プロセスの条件に加えて次の条件が必要となる。
【０１８１】
▲１▼マルチヘッドであること
▲２▼各ヘッドの流量を補正できること
上記▲２▼の理由について以下説明する。第２の実施例（図１６）で示したように、流体補給手段であるポンプと、ピストンを駆動する軸方向駆動手段を分離して塗布装置を構成すれば、１セットのポンプ部から複数個のピストン駆動部に流体を分枝して補給することにより、マルチノズルを有する塗布ヘッドが実現できる。
【０１８２】
図１９の矢視図において、２００は流体補給手段であるポンプ部、２０１，２０２，２０３は圧電アクチュエータとピストンで構成されるピストン駆動部Ａ，Ｂ，Ｃである。２０４は内部にポンプ部２００と前記ピストン駆動部を繋ぐ流通路（図１７の６４に相当）が形成された筐体である。
【０１８３】
通常、流体補給手段であるポンプ部の小型化は限界があるが、ピストン駆動部は小径の圧電アクチュエータ等の適用が可能であり、マルチヘッド構成にした場合、各ノズル間のピッチを充分小さくできる。
【０１８４】
図１９に示したマルチヘッドをサブユニットとして、このサブユニットを複数個組み合わせた塗布装置としてもよい。
【０１８５】
図２０はマルチヘッドの場合の等価回路モデルを示す。
【０１８６】
Ｐ_squ11、Ｐ_squ12、Ｐ_squ13は各ピストン駆動部の第１次スクイーズ圧力、Ｒ_p1，Ｒ_p2，Ｒ_p3はピストン端面の半径方向の流体抵抗、Ｒ_n1，Ｒ_n2，Ｒ_n3は各ノズル抵抗である。Ｒ_p1〜Ｒ_p3の大きさは（式８）で示されるように、隙間ｈの３乗に逆比例する。すなわちＲ_p1〜Ｒ_p3は、塗布装置を解体することなく各ヘッドの流量を個別に調節できる「可変抵抗」である。
【０１８７】
前述したシングルヘッドの実施形態では、ピストン端面の隙間ｈを充分に大きく設定して、第１次スクイーズ圧力の発生を極力押さえることにより、総逆流量Ｑ_s、或いは吐出ノズル上流側圧力Ｐ_iは隙間ｈの大きさに依存せず、ポンプ部の条件設定（例えば回転数）だけで決まる構成となっていた。１セットのポンプ部から複数個のピストン駆動部に流体を分枝して補給する場合、各ピストン駆動部の寸法精度、流路抵抗などが厳密に等しく構成できれば、ポンプ部から供給される流量は同一配分される。しかし、数％の塗布量の精度が要求されるディスプレイなどの塗布対象については、実用上は困難である。
【０１８８】
本実施形態では、各ピストンの最小隙間ｈ_minを個別に調整することにより、可変抵抗Ｒ_p1〜Ｒ_p3の大きさを変えることができ、塗布装置を解体することなく流量を調節できる。
【０１８９】
最小隙間ｈ_minの設定値が大きすぎると、最小隙間ｈ_minを変化させても流量に与える影響が小さくなるために流量調整が困難となる。図１３のグラフから、最小隙間ｈ_minは０＜ｈ_min＜ｈ_x2の領域に入るように設定すればよい。或いは、各ヘッドの流量差が十分に小さければ、隙間ｈ_minに対する流量のカーブがなだらかな特性をもつｈ_min≒ｈ_x2近傍を利用して、流量の微調整をすればよい。
【０１９０】
ピストンの変位は、ピストンの絶対位置を検出する変位センサーを配設して閉ループ制御を施せば、任意の位置決め制御が可能である。但し、圧電素子、超磁歪素子などの電磁歪素子を用いた場合は、ストローク限界（０〜数十ミクロン）があるために、ピストンの最小隙間ｈ_minの調節は、機械的な方法と電子制御による方法を組み合わせて用いてもよい。例えば、最初にピストンの位置を機械的に粗く位置決めした後、流量測定のデータを基に、電子制御を用いて再度各ヘッドのピストン位置を補正すればよい。
【０１９１】
また、流量調節に上記方法を用いる場合でも、供給源ポンプの出力流量の設定方法と併用すれば、ピストン端面隙間が充分に大きなところで、流量調節できる。例えば、流量が大きすぎて、ピストンの最小隙間ｈ_minを小さく設定せざるを得ない場合は、ねじ溝ポンプの回転数を低下させれば、ｈ_minは大きく設定できるようになる。この点は後述するように、紛流体を扱う場合に有利となる。
【０１９２】
マルチヘッドのヘッド間の流量差補正に用いた上記方策は、シングルヘッドの場合も適用できる。シングルヘッド、マルチヘッドいずれの場合でも、ポンプのモータ回転数を変える代わりに、ｈ_minを調節すれば高速流量制御ができる。モータの回転数制御の応答性は、せいぜい０．０１〜０．０５秒レベルであり限界があるが、電磁歪素子で駆動されるピストンの制御応答性は０．００１秒以下まで可能である。また、ピストンの最小隙間ｈ_minで流量を調節するのではなく、ピストン入力変位波形の平均値、或いは、中心値で流量を調節してもよい。
【０１９３】
なお、本発明における流体補給手段としてのポンプの形態は、ねじ溝式に限らず他の方式のポンプも適用可能である。例えば、スネイクポンプと呼ばれるモーノ式、ギヤ式、ツインスクリュウ式、シリンジ式ポンプなどが適用できる。
【０１９４】
図２１は、本発明に流体補給手段にギヤ式を用いた場合のモデル図であり、７００はギヤポンプ、７０１は流通路、７０２ａ，７０２ｂ，７０２ｃは例えば圧電アクチュエータなどで構成される軸方向駆動手段、７０３ａ，７０３ｂ，７０３ｃはピストンである。
【０１９５】
ポンプの最大流量Ｑ_max、最大圧力Ｐ_maxは通常は理論的に求められる場合が多いが、もしそれが困難な場合は実験的に求めても良い。
【０１９６】
ポンプの内部抵抗Ｒ_sは、動作点における圧力と流量をＰ_i、Ｑ_iとしたとき、動作点近傍で圧力と流量を微少量変化させて、Ｒ_s＝ΔＰ_i／ΔＱ_iとして実測してもよい。或いは、ポンプの流量と圧力の関係を実測し、動作点における特性曲線の勾配：ΔＰ_i／ΔＱ_iから内部抵抗を求めてもよい。ポンプとピストンの端面に至る流路に流体抵抗Ｒ_s2があれば、ポンプの上記内部抵抗Ｒ_sに加えた値：Ｒ_s0＝Ｒ_s＋Ｒ_s2を流体輸送手段の流体内部抵抗として定義し前述した理論を用いれば良い。この流体抵抗Ｒ_s2は例えば、通常よく知られた理論式（例えば（式７），（式８））などから理論的に求めてもよい。或いは、実験的に求めても良い。
【０１９７】
流体抵抗Ｒ_n、Ｒ_pも同様に（式７），（式８）から求められるが、形状が複雑ならば数値解析を用いるか、或いは実験的に求めても良い。内径に対して絞り部分長さが短いオリフィスの場合は、線形抵抗の式（例えば（式７））が成り立たなくなるが、この場合は動作点を中心に線形化して、見かけの流体抵抗とすればよい。
【０１９８】
ピストン駆動部を構成するピストンとその対向面の形状は、円形でなくてもよい。ピストンは長方形の形状でもよい。この場合は等価な面積を持つ円の半径を平均半径とする。微少流量を扱う本実施例のポンプでは、ピストンのストロークは、大きくとも数十ミクロンのオーダでよく、超磁歪素子、圧電素子などの電磁歪素子を用いても、ストロークの限界は問題とならない。
【０１９９】
応答性を犠牲にするならば、ピストンを駆動する軸方向駆動手段にムービングマグネット型、ムービングコイル型のリニアモータ或いは、電磁ソレノイド等を用いてもよい。この場合、ストロークの制約は解消される（図示せず）。
【０２００】
以上の説明は連続塗布だけについて記述したが、［３］具体的な実施の形態、或いは、［４］マルチヘッドの場合、で開示した塗布装置の構造は間欠塗布の場合でも適用できる。すなわち、連続塗布と間欠塗布を同一の塗布装置で兼ねて用いることも可能である。
【０２０１】
【発明の効果】
本発明を、例えばディスプレイの蛍光体塗布、電極層形成などに適用すれば、従来のスクリーンマスクを用いることなく、基板仕様を数値設定するだけで、任意のサイズの基板に対して、スクリーンストライブを精度よく形成することができると共に、基板の仕様変更に容易に対応できる。また、高速プロセスに対応できるために、従来工法と比べても生産タクトの点で遜色がなく、廃棄する材料がないために、材料ロスを大幅に削減できる。
【０２０２】
製造工程および製造ラインとも規模を拡大させる必要がなく、単体の装置でスクリーニングすることを可能にし、また多品種少量生産のディスプレイパネルに対して量産効果を上げて製造させ、さらに単体でスクリーニングするため自動化ラインを小規模なマシンで稼動できる。
【０２０３】
本発明は、ＰＤＰなどのディスプレイパネル以外でも、半導体、表面実装、液晶、透明タッチパネル、有機ＥＬ，シートデバイスなどの生産工程で用いることができ、その効果は絶大である。
【図面の簡単な説明】
【図１】本発明の原理を示すモデル図
【図２】時間に対するピストン変位を示す図
【図３】時間に対するねじ溝圧力を示す図
【図４】時間に対するスクイーズ圧力を示す図
【図５】時間に対する吐出ノズル上流側圧力を示す図
【図６】図１の吐出部詳細図
【図７】時間に対するピストン変位を示す図
【図８】内部抵抗Ｒ_sは無視できる程小さい場合の電気回路モデル図
【図９】時間に対する吐出ノズル上流側圧力を示す図
【図１０】内部抵抗Ｒ_sが大きい場合の電気回路モデル図
【図１１】時間に対する吐出ノズル上流側圧力を示す図
【図１２】総逆流量とピストン最小隙間の関係を示す図
【図１３】吐出ノズル上流側圧力とピストン最小隙間の関係を示す図
【図１４】流体抵抗Ｒ_p,Ｒ_sとピストン最小隙間の関係を示す図
【図１５】本発明をＰＤＰパネルの蛍光体層装置に適用した場合の概略斜視図
【図１６】本発明に適用した第１の実施の形態によるディスペンサーを示す正面断面図
【図１７】本発明に適用した第２の実施の形態によるディスペンサーを示す正面断面図
【図１８】本発明に適用した第３の実施の形態によるディスペンサーを示す正面断面図
【図１９】本発明をマルチヘッドに適用した場合のモデル図
【図２０】マルチヘッドの場合の電気回路モデルを示す図
【図２１】本発明の流体補給手段のねじ溝ポンプを用いたときのモデル図
【図２２】パネル面の有効表示領域と非有効表示領を示す図
【図２３】従来のエアー式ディスペンサーを示す図
【図２４】従来のディスペンサー方式蛍光体層塗布装置の概略斜視図
【符号の説明】
１ ピストン
２ ハウジング
５ ねじ溝
６ 吸入口
７ 下部プレート
８ 端面
９ 端面の固定側対向面
１０ 吐出ノズル
１１ 開口部
１２ 塗布流体
１３ ピストン端面の外周部
１４ 間隙部
１５ 上流側
１６ 流体輸送室[0001]
BACKGROUND OF THE INVENTION
The present invention is a pattern of minute flow rate required in the production process of display panels such as semiconductors, liquid crystals, surface mounts, or PDPs, liquid crystals, organic ELs, CRTs, etc. Success It is about the law.
[0002]
[Prior art]
Hereinafter, the problem of the prior art will be described by taking as an example the case of forming a screen stripe with a phosphor material on a display panel.
[0003]
A plasma display panel that performs color display (hereinafter referred to as “PDP”) has phosphor layers made of phosphor materials that emit light of RGB colors on the front plate / back surface. In this phosphor layer, three sets of stripes filled with phosphor materials of RGB colors are formed between the barrier ribs formed in parallel lines on the front plate / back surface (that is, on the address electrodes). It has a structure in which a large number of three sets of stripes are arranged adjacent to each other in parallel. This phosphor layer is formed by a screen printing method, a photolithography method or the like.
[0004]
When the screen is enlarged, it is difficult to align the screen printing plate with high accuracy with the conventional screen printing method, and when trying to fill the phosphor material, the material is placed on the top of the partition wall, and it is removed. Therefore, measures such as the introduction of a polishing process were necessary. Moreover, the filling amount of the phosphor material changes due to the difference in the squeegee pressure, and the pressure adjustment is very delicate and often depends on the skill level of the operator. Therefore, it is not easy to obtain a constant filling amount over the front plate / back surface.
[0005]
In addition, a phosphor layer can be formed by a photolithography method using a photosensitive phosphor material, but exposure and development processes are required, and the number of processes is increased compared to the screen printing method. There was a problem that the cost was high.
[0006]
A phosphor screen stripe of a color cathode ray tube panel is usually manufactured by a photographic development method using an exposure table. In this method, a phosphor according to one of the three primary colors is applied to the entire panel surface.
[0007]
As this coating method, for example, a so-called “swinging method” is used in which after the phosphor liquid is injected into the inner surface of the panel, the panel body is rotated to apply a centrifugal force to the phosphor liquid to make the phosphor material uniform on the entire panel surface.
[0008]
The above-mentioned panel coated with phosphor on the entire surface and the mask are combined, and only the stripe position of this color phosphor is exposed on the exposure stand, the development chemical treatment is performed to leave the exposed area, and the remaining mask covering area is formed. Remove. Next, the photolithography process for mask exposure and development is repeated for each of the phosphors of the other three primary colors. Therefore, the photolithography process is repeated three times.
[0009]
As a method for forming the phosphor screen stripe, an electrostatic coating method is also applied. This method is the same as the photographic development method in principle, but differs in that a stripe color phosphor is applied by dry coating using a charging material.
[0010]
When the phosphor screen stripe of the cathode ray tube panel is formed by both of the above methods, a large-scale manufacturing apparatus is required because any of the methods requires many complicated processes. Therefore, it is suitable for mass production, but has a disadvantage that it is inefficient for large variety and small quantity production.
[0011]
Direct drawing method using a dispenser in order to solve the above-mentioned problems related to the problem of forming screen stripes, that is, the screen printing method in the PDP and the “swinging method → photo development method” in the color cathode ray tube panel (Direct patterning) has already been proposed.
[0012]
FIG. 24 is disclosed in Japanese Patent Application Laid-Open No. 10-27543 and shows a phosphor layer forming apparatus and a forming method for a PDP.
[0013]
In FIG. 24, 450 is a substrate, 451 is a mounting table on which this substrate is placed, 452 is a dispenser that discharges a paste-like phosphor, and 453 is a discharge nozzle of the dispenser. A pair of Y-axis direction transport devices 454a and 454b are provided on both sides of the mounting table 451 in order to configure a transport unit that relatively moves the discharge nozzle and the mounting table. An X-axis direction transport device 455 is mounted so as to be movable in the Y-axis direction by the Y-axis direction transport device. Further, a Z-axis direction transfer device 456 is mounted so as to be movable in the X-axis direction by the X-axis direction transfer device 455.
[0014]
According to the above proposal, the phosphor is discharged from the nozzle 453 that moves on the substrate only by setting the numerical value of the substrate without using the conventional screen mask, and is applied to the groove between the ribs. The phosphor layer can be accurately formed on the substrate and can easily cope with a change in the specifications of the substrate.
[0015]
A similar proposal has already been disclosed in Japanese Patent Publication No. 57-21223 for a phosphor layer forming apparatus for a color cathode ray tube panel. According to this proposal, it is not necessary to increase the scale of both the manufacturing process and the manufacturing line, it is possible to perform screening with a single device, and to produce a mass production effect for a large variety of small-volume CRTs. It is said that there is an advantage of operating the automation line on a small machine because it screens alone.
[0016]
[Patent Document 1]
Japanese Patent Laid-Open No. 10-27543
[Patent Document 2]
Japanese Patent Publication No.57-21223
[0017]
[Problems to be solved by the invention]
Even when a phosphor screen stripe is formed on the panel surface using a dispenser, a production tact equivalent to the screen printing method is desired. However, there are restrictions on the number of dispensers that can be arranged in the coating apparatus, and in order to draw thousands to thousands of screen stripes in as short a time as possible, the relative speed between the panel and the nozzle needs to be sufficiently large. . For this purpose, it is necessary to reciprocate the transport table on which the dispenser or the panel is mounted with high accuracy and high speed.
[0018]
Here, the panel surface has an “effective display area” (360a in FIG. 22) for forming a phosphor layer, and an “ineffective display area” (360b in FIG. 22) that does not form a phosphor layer on the outer periphery of the effective display area. ).
[0019]
In addition, it is assumed that the dispenser is mounted on a transport table, and attention is paid to the behavior of one discharge nozzle. When the nozzle that has traveled at high speed while continuously coating the “effective display area” (360a in FIG. 22) on the panel surface approaches the end face of the panel, the nozzle decreases its speed through a deceleration zone, and the “ineffective display area” (FIG. 22). 360b). After the U-turn in this non-effective display area, the effective display area is steadily traveled again through the approach section.
[0020]
That is, the relative speed between the nozzle and the panel changes greatly before and after the U-turn section. At this time, the dispenser desirably has the following functions.
[0021]
(1) The flow rate can be varied according to the relative speed between the nozzle and the panel.
[0022]
{Circle around (2)} The discharge amount can be completely blocked in the U-turn section (the section that travels in the “ineffective display area”) on the end face of the panel.
[0023]
(3) After the U-turn section, “thinning”, “cut”, etc. do not occur at the starting point of the coating line at the start of coating. Similarly, no “thickness” or “reservoir” occurs at the end point of the coating line at the end of coating.
[0024]
If the above (1) cannot be realized, for example, even if the relative speed between the nozzle and the panel is smaller than in the case of steady running, if the discharge amount cannot be reduced, the line width and thickness of the fluorescent coating line will be It will exceed the specified specs.
[0025]
The higher the production tact, the shorter the rise and fall times and the greater the relative rate of change. That is, the dispenser is required to have a higher flow rate control response.
[0026]
The necessity of (2) above is as follows. When the nozzle travels in a U-turn section (“ineffective display area”) on the end face of the panel, the relative speed between the nozzle and the panel is zero and extremely low before and after that.
[0027]
If there is a material outflow from the nozzle in this section, the material is deposited on the panel because a plurality of stripes overlap even at a small flow rate. As a result, the deposited material adheres to the tip of the discharge nozzle. When the application was started again in this state, the fluid mass attached to the tip of the discharge nozzle dissipated discontinuously on the panel surface, causing troubles such as remarkably degrading the accuracy of the drawing line. That is, it is preferable that the dispenser can completely block the discharge amount in the U-turn section of the end face of the panel.
[0028]
The above (3) is an indispensable condition for ensuring a quality equivalent to or higher than that of the conventional method, for example, the screen printing method.
[0029]
In summary, in order to form a phosphor screen stripe on the panel surface with high production efficiency using a dispenser, the dispenser has a function that can optionally shut off and open the fluid, and has a high flow control response. And high flow accuracy are desirable. However, a detailed description of this point is not found in JP-A-10-27543 and JP-B-57-21223, which are prior examples of the dispenser system.
[0030]
Now, dispensers (liquid ejecting devices) have been used in various fields, but in response to the recent needs for downsizing and high recording density of electronic components, a small amount of fluid material can be accurately and stably stabilized. Therefore, a technology for controlling the supply is demanded. Conventionally, air-type dispensers as shown in FIG. 23 have been widely used as liquid ejection devices, and the technology is introduced in, for example, “Automation Technology '93 .25 No. 7”.
[0031]
The dispenser by this system applies a constant amount of air supplied from a constant pressure source in a container (cylinder) 600 in a pulsed manner, and discharges a certain amount of liquid corresponding to the pressure increase in the cylinder 601 from the nozzle 602. Is.
[0032]
This air type dispenser has the following problems.
[0033]
(1) Discharge variation due to discharge pressure pulsation
(2) Discharge variation due to water head difference
(3) Discharge amount change due to liquid viscosity change
The phenomenon (1) is more noticeable as the tact time is shorter and the discharge time is shorter. For this reason, a contrivance has been made such as providing a stabilization circuit for making the height of the air pulse uniform.
[0034]
In (2), since the volume of the gap 601 in the cylinder varies depending on the remaining amount of liquid H, when a certain amount of high-pressure air is supplied, the degree of pressure change in the gap 601 varies greatly with H. The reason is that. If the remaining amount of liquid is reduced, there is a problem that the coating amount is reduced by, for example, about 50 to 60% compared to the maximum value. For this purpose, measures are taken such as detecting the remaining amount of liquid H for each discharge and adjusting the time width of the pulses so that the discharge amount becomes uniform.
[0035]
The above (3) occurs, for example, when the viscosity of a material containing a large amount of solvent changes with time. As countermeasures, measures such as adjusting the pulse width so as to correct the influence of the viscosity change by programming the tendency of the viscosity change with respect to the time axis in advance in a computer have been taken.
[0036]
Any of the measures for the above problems is not a drastic solution because a control system including a computer becomes complicated and it is difficult to cope with irregular environmental conditions (such as temperature).
[0037]
In addition to the above problems of the air method, this type of dispenser has a drawback of poor responsiveness. This drawback is due to the compressibility of the air confined in the cylinder 600 and the nozzle resistance when the air passes through a narrow gap. That is, in the case of the air system, the time constant of the fluid circuit determined by the cylinder volume: C and the nozzle resistance: R: T = RC is large, and after applying the input pulse, for example, about 0.07 to 0.1 seconds at the start of discharge I have to expect the time delay.
[0038]
In order to eliminate the disadvantages of the air method, a dispenser that opens and closes the discharge port by providing a needle valve at the inlet of the discharge nozzle and moving a small-diameter spool constituting the needle valve at high speed in the axial direction. Has been put to practical use. However, in this case, when the fluid is shut off, the gap between the relatively moving members becomes zero, and the powder having an average particle diameter of several microns to several tens of microns is mechanically squeezed and destroyed. Due to various problems that occur as a result, it is often difficult to apply the present invention to a phosphor or the like that is the subject of the present invention.
[0039]
For the above reasons, even if the structure or application method of the conventional dispenser is introduced as it is, it is difficult to satisfy the conditions for forming the phosphor screen stripe on the panel surface with high production efficiency.
[0040]
The problem of the prior art has been described above by taking as an example the case where a screen stripe is formed of a phosphor material on a display panel. In the case of pattern formation with materials other than phosphor screen stripes, such as electrode materials, the problem is the same even in the case of circuit formation in surface mounting.
[0041]
In the specification of Japanese Patent Application No. 2001-385804, the present inventors have already provided thin film patterns such as phosphors and electrode materials on the display panel surface by giving the dispenser the functions of high-speed discharge blocking, high-speed discharge opening, and flow rate control. Conditions for forming with high production efficiency,
(1) The flow rate can be varied with high responsiveness according to the acceleration / deceleration of the stage.
[0042]
{Circle around (2)} High-speed fluid shut-off and high-speed release can be optionally performed when the nozzle tip moves from the coating area to the non-coating area or vice versa.
The invention which satisfies the above is proposed. As a result of further detailed theoretical analysis for the dispenser structure proposed in the above proposal, the present invention has found conditions for further uniformizing and stabilizing the coating amount.
[0043]
[Means for Solving the Problems]
In the pattern forming method of the present invention, a fluid is supplied to a fluid transport chamber formed of a cylinder and a piston and communicated with a suction hole port and a discharge nozzle, and a relative axial direction is provided between the piston and the cylinder. Give exercise and start application A gap h formed between the discharge-side end surface of the piston and its opposing surface When application is cut off Gap h The Than at the start of application In the pattern forming method in which the fluid is continuously applied and formed from the discharge nozzle by increasing the fluid resistance between the outer peripheral portion of the piston end surface and the suction port, Rs, Gap while h When the fluid resistance of the radial flow path is Rp, When continuously applying and forming the fluid, the relationship between Rs and Rp is determined while rotating the piston. Rs> Rp And the gap h is kept larger than 50 μm, while the rotation of the piston is stopped when the application is cut off. It is characterized by that.
[0047]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in the following order.
[0048]
[1] Basic structure of dispenser and example of control method of start / end
[2] Flow rate shutoff principle of the present invention
[3] Specific embodiment
[4] Other application examples: Multi-head
First, the above [1] will be described.
[0049]
FIG. 1 is a model diagram showing a first embodiment of the present invention. In FIG. 1, 1 is a piston, 2 is a housing which accommodates this piston. The piston 1 is accommodated so as to be rotatable and axially movable with respect to the housing 2 on the fixed side. The piston 1 is driven by axial driving means (arrow 3) and rotation transmission means (arrow 4).
[0050]
Reference numeral 5 denotes a thread groove (blackened portion) formed on the relative movement surface of the piston 1 and the housing 2, 6 denotes a fluid inlet, and 7 denotes a lower plate. 8 is an end surface of the piston 1, 9 is a fixed-side facing surface thereof, 10 is a discharge nozzle formed at the center of the fixed-side facing surface 9, and 11 is an opening of the discharge nozzle 10 formed on the fixed-side facing surface 9. is there.
[0051]
The piston end surface 8 and the fixed-side facing surface 9 are two surfaces that relatively move in the gap direction. A coating fluid 12 is supplied between the piston 1 and the housing 2. Reference numeral 13 denotes an outer peripheral portion of the piston end surface, and a fluid is supplied into the outer peripheral portion 13 of the piston end surface by a thread groove pump which is a fluid supply means. Reference numeral 14 denotes a gap between the piston end surface 8 and the facing surface 9. 15 is located at the center of the gap 14 and is called the upstream side of the discharge nozzle. A space formed by the piston 1 and the housing 2 and filled with a fluid is referred to as a fluid transport chamber 16. The axial driving means 3 (specific structure is not shown) is provided between the piston 1 and the housing 2, and changes the axial relative position between the members 1 and 2. The axial driving means 3 can change the gap h between the piston end surface 8 and the opposed surface 9.
[0052]
Now, in the present embodiment, the problem related to the start and end of the coating line is achieved by the following method using the fact that the piston driven by the giant magnetostrictive element can perform a high-speed linear motion simultaneously with the rotation.
[0053]
(1) At the start of application, the piston is rapidly lowered and simultaneously the motor starts to rotate.
[0054]
(2) At the end of coating, the piston is raised and the motor is stopped.
[0055]
FIG. 2 shows a displacement curve of a piston driven by the axial direction drive means, and FIG. 3 shows a pumping pressure P of a thread groove generated when the rotational speed of the motor is raised from N = 0 rpm to N = 200 rpm. _p Indicates. FIG. 4 shows the squeeze pressure P generated by raising and lowering the piston. _s The analysis results are shown. FIG. 6 shows the pumping pressure P of the thread groove. _p And squeeze pressure P _s Pressure P synthesized _n (= P _p + P _s ). Each pressure is a value on the upstream side of the discharge nozzle (15 in FIG. 1).
[0056]
(1) At the start of application
In the state before the start of coating, the rotation of the motor is stopped, and the piston is in a state of a gap with the facing surface: h = 160 μm (FIG. 2). When t = 0.02 seconds, the piston starts to suddenly drop to the gap: h = 160 → 150 μm, the upstream pressure of the discharge nozzle: P _n (Pressure at point 15 in FIG. 1) rises rapidly. The reason is due to the squeeze action that occurs when the Reynolds equation of (Equation 1) described later is dh / dt <0. The squeeze action is a kind of dynamic pressure effect of a fluid bearing using a viscous fluid. Due to the generation of a steep peak pressure (overshoot) due to the squeeze effect, a large kinetic energy that overcomes the surface tension at the tip of the discharge nozzle is given to the fluid, so that application can be started without creating a fluid mass at the tip of the nozzle. In order to smoothly draw the coating line at the starting point, the overshoot pressure increases as the piston stroke increases and the rise time decreases. That is, the magnitude of the overshoot pressure may be set within a range where the surface tension of the fluid at the tip of the discharge nozzle is overcome and the coating line does not become “thick” at the start point.
[0057]
(2) During steady running
During 0.03 <t <0.07 seconds, the piston is kept at a gap with the facing surface: h = 150 μm, and the pumping pressure P due to the rotation of the thread groove _p A continuous line is applied by the quantitative discharge. Although there is a fluid resistance between the piston and its opposing surface, the required flow rate can be discharged because the fluid resistance of the gap: h = 150 μm is sufficiently small. In this section, since the gap h does not change, no squeeze pressure is generated.
[0058]
(3) At the end of application
At t = 0.07 seconds, simultaneously with the deceleration of the motor, when the piston starts to rise to the gap: h = 150 → 160 μm, the upstream pressure P of the discharge nozzle _n As shown in FIG. The reason for the large negative pressure is that the Reynolds equation does not consider the compressibility of the fluid. The fluid pressure is actually P due to the generation of bubbles. _n <-0.1 MPa (gauge pressure) is not reached.
[0059]
This steep negative pressure generation not only shuts off the fluid from the discharge nozzle, but also provides a suck back effect of sucking a small amount of fluid mass at the tip of the nozzle into the nozzle. After the negative pressure due to the squeeze pressure is generated, the rotation of the motor is stopped, so that there is no discharge due to the pumping pressure of the thread groove. Therefore, while the nozzle passes through the ineffective display area (U-turn section), the meniscus of the fluid inside the nozzle keeps the same position without forming a fluid mass at the nozzle tip. For this reason, the above-mentioned troubles such as dropping of the fluid block can be avoided.
[0060]
[2] Flow rate shutoff principle of the present invention
The method for controlling the start and end of the coating line is the content disclosed in Japanese Patent Application No. 2001-385804 filed in application, but in the embodiment of the present invention, compared with the invention described in the above specification. The configuration conditions of the pump are different as follows.
[0061]
(1) Minimum clearance of piston end face during steady application: h = h _min When h _min The set value of is sufficiently large, for example, h _min > 50 μm.
[0062]
(2) The thread groove pump is quantified and its internal resistance R _s Is big enough.
[0063]
When the gap h is increased in order to block the flow rate at the end of coating, the piston end surface 8 and its opposing surface 9 are affected by the primary squeeze effect of the viscous fluid and the secondary squeeze effect newly found in this proposal. A large negative pressure is generated in the gap between them.
[0064]
This embodiment utilizes the point that if this secondary squeeze effect is used, the fluid can be shut off and opened at high speed even if the gap h between the piston end faces is kept sufficiently large. This is intended to further stabilize.
[0065]
(1) Derivation of basic formula
Now, in order to clarify the principle and effect of the present invention, which is different from the previous proposal, a basic expression of a squeeze pump (tentative name) is derived. When a viscous fluid is present in a narrow gap between planes arranged opposite to each other and the gap interval changes with time, the fluid pressure is the Reynolds equation in the following polar coordinates having a squeeze action term. Is obtained by solving
[0066]
[Expression 4]

[0067]
In (Expression 1), p is the pressure, μ is the viscosity coefficient of the fluid, h is the gap between the opposing surfaces, r is the radial position, and t is time. The right side is a term that provides a squeeze action effect that occurs when the gap h changes. FIG. 6 shows the dimensional relationship of the squeeze pump unit. As h = dh / dt, both sides of (Expression 1) are integrated. Undecided constant C from boundary condition of pressure and flow rate ₁ , C ₂ The detailed procedure for obtaining is omitted, but the pressure at the radial position r is
[0068]
[Equation 5]

[0069]
However,
[0070]
[Formula 6]

[0071]
In Formula 3), R _s Is the internal resistance of the thread groove pump, P _S0 Is the supply pressure, and the maximum generated pressure P of the thread groove pump (fluid supply means) _max And auxiliary pressure P by air for supplying material to the thread groove _sup Sum of (P _S0 = P _sup + P _max ).
[0072]
Discharge nozzle opening: r = r _i (15 in FIG. 1), P _i = A + BQ _i And The fluid resistance of the discharge nozzle is R _n Then, the flow rate passing through the discharge nozzle is Q _n = P _i / R _n It is. Q from flow continuity _i = Q _n And the pressure P at the opening of the discharge nozzle _i Is obtained as follows. A _i , B _i R = r in (Equation 2) _i Are the values of A and B.
[0073]
[Expression 7]

[0074]
In the above formula, R _n Is the discharge nozzle resistance, R _p Is the thrust fluid resistance between the piston end face and its opposing face. Where the primary squeeze pressure P _squ1 , Secondary squeeze pressure P _squ2 Is defined as follows.
[0075]
[Equation 8]

[0076]
Primary squeeze pressure P _squ1 This is due to a known squeeze effect generated between the piston end faces by abruptly changing the gap between the piston end face and the relative movement surface. A larger pressure is generated as the gap h is narrower.
[0077]
Secondary squeeze pressure P _squ2 The present invention has found a method for generating the ink and a method for applying this action to the discharge blocking and discharge opening of the continuous coating, and the principle is as follows. By rapidly changing the gap between the piston end surface and its relative movement surface, a flow rate fluctuation occurs between the end surface of the piston and the fluid supply source. This flow rate fluctuation corresponds to a volume change when the gap is changed. For example, when the volume increases due to the piston rising, if the maximum flow rate that can be supplied by the thread groove pump is less than the volume change, negative pressure is generated on the piston end face.
[0078]
From (Expression 4) and (Expression 5), the pressure P at the opening of the discharge nozzle _i Is
[0079]
[Equation 9]

[0080]
Flow rate Q _i Is the discharge nozzle resistance R _n Q _i = P _i / R _n It is.
The nozzle radius of the discharge nozzle is r _n , The nozzle length is l _n The discharge nozzle resistance is
[0081]
[Expression 10]

[0082]
R _p Is the thrust fluid resistance between the upstream side of the discharge nozzle (15 in FIG. 1) and the piston outer peripheral portion (pump chamber end 13 in FIG. 1), as described above. R _s Is the fluid resistance (internal resistance in the case of a thread groove pump) of the flow path between the outer peripheral portion 13 of the piston end face and the supply source side (suction port), as described above.
[0083]
[Expression 11]

[0084]
(2) Pressure characteristics when fluid is shut off / open
Hereinafter, the calculation for obtaining the pressure on the upstream side of the discharge nozzle (15 in FIG. 1) is performed as follows: [i] Internal resistance R of fluid supply means _s [Ii] corresponds to the present invention, and the fluid replenishing means has an internal resistance R. _s In case of having, it is divided into two cases.
[0085]
FIG. 7 is a piston displacement curve common to the above calculations [i] and [ii]. The amplitude Δh = 10 μm is constant and the minimum gap h is set. _min The case where is changed variously is shown. Table 1 shows the analysis conditions.
[0086]
[I] Internal resistance R of fluid supply means _s Is small enough to be ignored
In this case, P in (Equation 5) _squ2 → 0, the pressure source is the primary squeeze pressure P _squ1 Only. This is equivalent to supplying the material by air pressure without using a screw groove type pump as the fluid supply means. Even when a thread groove pump is used, it is equivalent if its internal resistance is small.
[0087]
The relationship between the pressure generation source and the load resistance is represented by an electric circuit model as shown in FIG. In FIG. 8, P _max Is the maximum generated pressure of the fluid replenishing means (thread groove type), R _n Is the fixed resistance of the discharge nozzle, R _p Is a variable fluid resistance in the radial direction of the thrust end face, and varies depending on the size of the gap h. FIG. 9 shows the pressure P at the discharge nozzle opening when the piston displacement curve of FIG. 7 is given. _i Is what we asked for. A positive peak pressure due to the squeeze effect occurs in the interval 0.02 <t <0.03 seconds when the discharge is released, and a negative peak due to the reverse squeeze effect occurs in the interval 0.07 <t <0.08 seconds when the discharge is shut off. The peak pressure is generated.
[0088]
A section where 0 <t <0.02 seconds is A, a section where 0.03 <t <0.07 seconds is B, and a section where t> 0.08 seconds is C. The pressure in section B decreases compared to sections A and C. Thrust resistance R in section B _p This is because of the increase.
[0089]
Minimum value h of gap h _min As the pressure increases, (1) the pressure in the sections A, B, and C increases, and (2) the amplitude of the squeeze pressure decreases. Minimum clearance h for reasons of (1) and (2) above _min When it is> 30 μm, the minimum value of the negative peak pressure is P in the section of 0.07 <t <0.08 seconds when the discharge is cut off. _min <0. That is, the minimum clearance h _min If it is> 30 μm, the discharge cannot be blocked.
[0090]
[Ii] Internal resistance R sufficiently large for fluid supply means _s (Invention)
In this case, for example, a thread groove pump is used as the fluid supply means, and the internal resistance R of the thread groove pump _s Is equivalent to a sufficiently large value. FIG. 10 shows an equivalent electric circuit model.
[0091]
FIG. 11 shows the pressure P upstream of the discharge nozzle when the displacement curve of the piston of FIG. 10 is given. _i Is what we asked for. Compared to the above [i], the pressures in the sections A, B, and C do not change greatly. A positive peak pressure due to the squeeze effect occurs in the interval of 0.02 <t <0.03 seconds when the discharge is released, and a negative peak due to the reverse squeeze effect occurs in the interval of 0.07 <t <0.08 seconds when the discharge is cut off. The point at which the peak pressure is generated is the same as in the above [i].
[0092]
However, if the minimum gap is increased, contrary to the intuitive prediction, the absolute value P of the peak pressure is contrary to the above [i]. _imax The surprising result is that increases. The reason for this will be described using the equivalent electric circuit model of FIG. 10 as follows.
[0093]
Minimum clearance h _min Increases, the primary squeeze pressure P _squ1 → 0, but at the same time the thrust fluid resistance R of the piston end face and the opposite face _p → 0, so the partial pressure ratio (= R _n / (R _s + R _p + R _n ) Increases. P _squ1 → If the effect of increasing the voltage division ratio is greater than the effect of 0, h _min When the pressure increases, the pressure P _i The amplitude of increases. However, in this embodiment, the minimum gap h _min As the value approaches 50 μm, the degree of pressure increase decreases.
[0094]
(2) Interrupting performance evaluation
As for the starting point at the start of application, the overshoot pressure (peak squeeze pressure peak value) is large within the range where the surface tension of the fluid at the tip of the discharge nozzle is overcome and the application line at the start point does not become “thick”. You just have to set it. For this purpose, the length of the rising section of the piston displacement curve (in FIG. 7, Δt = 0.02 seconds) may be adjusted. If Δt is shortened, the overshoot pressure increases, and if Δt is lengthened, the overshoot pressure decreases and the pressure waveform becomes dull.
[0095]
About the end point at the start of application, it is usually better to be able to block as sharply as possible. In order to evaluate the sharpness, that is, the shut-off performance of the dispenser, the shut-off (discharge flow rate Q _i Total reverse flow Q when discharge is cut off at <0) _s Ask for.
[0096]
[Expression 12]

[0097]
Integration range t ₁ And t ₂ Is the discharge flow rate Q _i It is the time at the start and end when <0. As described above, since the actual pressure at the time of shut-off does not become an absolute pressure of 0 atm or less, the value obtained from (Equation 9) is not an actual reverse flow rate. However, the above formula is useful in making a relative comparison of the “blocking performance” under various conditions.
[0098]
FIG. 12 shows the minimum clearance h of the piston end surface. _min Total reverse flow Q when discharge is blocked for _s Is obtained using (Equation 9). Hereinafter, the internal resistance R of the pump _s = 0 and R _s Note the case of = 0.05.
[0099]
Internal resistance R of the pump _s = 0, the minimum gap h _min Increases, the total reverse flow Q _s Will decline. Minimum clearance h _min If it is> 30 μm, no backflow occurs and complete discharge blocking cannot be performed.
[0100]
Internal resistance R _s = 0.05, minimum clearance h _min Increases, the total reverse flow Q _s Will increase, but h _min = H _x1 When it exceeds the vicinity (≈40μm), the total reverse flow Q _s Is h _min A constant value is maintained without depending on.
[0101]
Where h _x1 Is defined as follows. Total reverse flow Q _s The setting range of the minimum value of the gap is 0 <h. _min <H _x1 , Total reverse flow Q _s Is insensitive to changes in the gap _min Set the setting range to h _min > H _x1 And h _x1 Is 0 <h _min <H _x1 H in the region _min Curve Q for _s Envelope and h _min → Q at ∞ _s = Q _se Is the intersection of
[0102]
The following supplements the conditions that allow complete discharge blocking.
[0103]
Minimum clearance h _min Is 0 <h _min <H _x1 Or h _min ≒ h _x1 If it is in the vicinity, the pressure P in (Equation 4) _i However, it may be negative when the discharge is cut off (when the time differential of the gap h takes the maximum value). That is, the primary squeeze pressure P when the time derivative of the gap h has a maximum value. _squ1 = P _squ10 , Secondary squeeze pressure P _squ2 = P _squ20 P _S0 + P _squ10 + P _squ20 <0 is sufficient.
[0104]
Minimum clearance h _min Is h _min >> h _x1 In the range of (1), if h → ∞ in (Expression 4), the primary squeeze pressure P _squ1 → 0, R _p Since it becomes 0, the following equation is obtained. However, P _s0 ≒ P _max , R _s = P _max / Q _max And
[0105]
[Formula 13]

[0106]
The second term of (Formula 9) corresponds to the geometric volume change of the piston end surface portion 14 formed by the piston end surface 8 and the opposed surface 9 thereof. When discharging is cut off, the maximum value of time differentiation is V _max , Q is the maximum flow rate of the fluid supply means _max When
[0107]
[Expression 14]

[0108]
Is satisfied, the pressure P _i Since it becomes negative pressure, the discharge is cut off.
[0109]
In the graph of FIG. 12, the internal resistance R _s Becomes smaller, the convergence value Q of the total reverse flow rate _s → Q _se The size of is decreasing. However, under any condition, the minimum clearance h _min > H _x1 Total reverse flow Q in the area _s Is h _min The point of keeping a constant value without depending on is unchanged. That is, the minimum gap h _min > H _x1 If set to internal resistance R _s Regardless of the size, the characteristics of the present invention can be utilized in that the blocking performance is not affected by the gap, and the steady-state flow rate is not affected by the gap as described later.
[0110]
FIG. 13 shows the minimum clearance h at the piston end face. _min Discharge nozzle upstream pressure P during discharge _i Is what we asked for. h _x2 Is similarly defined as follows. Pressure P _i The setting range of the minimum value of the gap is 0 <h. _min <H _x2 , Pressure P _i Is insensitive to changes in the gap _min Set the setting range to h _min > H _x2 And h _x2 Is 0 <h _min <H _x2 H in the region _min Curve P for _i Envelope and h _min → P at ∞ _i = P _ie Is the intersection of
[0111]
Minimum clearance h _min Increases, the pressure P _i Will increase, but h _min = H _x2 If it exceeds the vicinity (≒ 40μm), the pressure P _i Is h _min A constant value is maintained without depending on. That is, h ₀ > H _x2 If the piston end face position is slightly increased or decreased due to thermal expansion of the members, variations in parts processing accuracy and assembly accuracy, etc., the pressure P _i (Ie discharge flow rate Q _n = P _i / R _n ) Is immutable. h _x2 The value may be obtained analytically using (Equation 4), but may be obtained by actually measuring the flow rate by changing the piston position. At this time, Q _ne = P _ie / R _n It is.
[0112]
As can be seen by comparing the graphs of FIGS. 12 and 13, h _x1 ≒ h _x2 And h _x2 If h is found, h _x1 Can be estimated.
[0113]
FIG. 14 shows the fluid resistance R of the piston discharge side end face. _p And minimum gap h _min Is a relationship. Minimum clearance h _min Increases, the fluid resistance R _p Will drop significantly. R against gap _p The characteristic is that the shut-off performance using only the first squeeze pressure (internal resistance R of the pump) _s = 0)).
[0114]
That is, the internal resistance R of the pump _s Is the fluid resistance R of the piston discharge side end face _p Minimum gap h sufficiently larger than _min This area is the driving condition of the head of this embodiment.
[0115]
Above, total reverse flow Q _s , Discharge nozzle upstream pressure P _i (Or flow rate Q _n ), Thrust fluid resistance R _p The minimum clearance h of the piston end face _min Organized in relation to This minimum gap h _min For example, the maximum value, the average value, the center value of the amplitude, etc. of the piston displacement are represented by the representative value h. ₀ It may be used as
[0116]
[Table 1]

[0117]
[3] Specific embodiment
Hereinafter, an embodiment in which the present invention is applied to a PDP phosphor layer forming method and forming apparatus will be described with reference to a schematic perspective view of FIG.
[0118]
In FIG. 15, 350 is a mounting table for mounting a panel. A pair of Y-axis direction transfer devices 351 and 352 are provided across both sides of the mounting table 350. In addition, an X-axis direction transport device 353 is mounted on the Y-axis direction transport device so as to be movable in the YY ′ direction. Further, a Z-axis direction transport device 354 is mounted on the X-axis direction transport device so as to be movable in the direction of arrow XX ′. On the Z-axis direction transport device 354, a syringe mounting portion 356 on which the dispenser 355 is detachably mounted is mounted so as to be movable in the ZZ ′ direction.
[0119]
The Y-axis direction conveyance devices 351 and 352 convey the X-axis direction conveyance device 353 by Y-axis motors 357a and 357b. Further, the X-axis direction transport device 353 transports the Z-axis direction transport device 354 by the X-axis motor 358. Further, the Z-axis direction transport device 354 transports the syringe mounting portion 356 by a Z-axis motor (not shown).
[0120]
With the above apparatus, a fluorescent layer is formed on the substrate for PDP. First, a syringe 359 containing a paste-like phosphor for forming a red (R) phosphor layer is attached to the dispenser 355. As shown in FIG. 22, the PDP substrate has an effective display area 360a for forming the phosphor layer and an ineffective display area 360b for forming no phosphor layer on the outer periphery of the effective display area (the substrate 361 is shown in FIG. 15). Not shown).
[0121]
The substrate 361 is mounted on a predetermined position of the mounting table 350 and fixed. For example, in the case of a 42-inch PDP substrate, the effective display area 360a of the substrate 361 made of a glass plate having a thickness of 3.0 mm has a length L = 560 mm and a height H in advance in parallel with the arrow XX ′ direction. 1921 ribs (light absorption layers) having a pitch of 100 μm and a width of W = 50 μm are formed with a pitch P therebetween. Since 1920 grooves are formed by these 1921 ribs, the RGB phosphors are applied to 640 (= 1920/3) grooves, respectively.
[0122]
First, the dispenser 355 is moved to the R phosphor application start position, and the tip of the discharge nozzle 349 is positioned at a predetermined height by the Z-axis motor.
[0123]
Next, the discharge of the R phosphor from the discharge nozzle 349 is started, and at the same time, the phosphor is applied by moving in the arrow X direction. When the discharge nozzle 349 draws a coating line by the length L of one rib (FIG. 22) and the tip of the discharge nozzle 349 enters the non-effective display area 360b from the effective display area 360a, the discharge of the phosphor stops.
[0124]
Further, the discharge nozzle 349 moves in the arrow Y direction by 3P while stopping the discharge of the phosphor. Again, at the same time as the discharge of the R phosphor from the discharge nozzle 349 is started, the phosphor coating is resumed by moving in the direction of the arrow X ′. When the above steps are repeated and the number of coatings reaches 640, the work with the R phosphor is finished.
[0125]
The above is the basic step of applying the phosphor, but for the remaining G phosphor and B phosphor, the panels may be sequentially transferred to the G phosphor and B phosphor dedicated mounting tables installed separately. . Alternatively, three types of dispensers (for RGB phosphor coating) may be disposed on the same mounting table.
[0126]
In addition, the position of the start and end of the discharge nozzle, the start and end timing of application, and the control of the application amount synchronized with the speed of the stage are based on pre-programmed start and end position information, and displacement and speed information from the stage. Based on. In this way, when the formation of the RGB phosphor layers along the inner surface shape of the groove between the ribs is completed, the tip position of the discharge nozzle of the dispenser returns to the home position. When the screen stripe application process is completed, the substrate is transferred to the phosphor drying process.
[0127]
Hereinafter, a first embodiment of a dispenser applied to a phosphor layer forming method and a forming apparatus of the present invention will be described with reference to FIG.
[0128]
The dispenser of the present embodiment described below has a “two-degree-of-freedom actuator” that simultaneously gives a relative rotational motion and a linear motion between a piston and a sleeve that houses the piston. That is,
(1) Positive and negative squeeze pressure is generated on the discharge side end face of the piston by linearly driving the piston with the first actuator.
[0129]
{Circle around (2)} A second actuator that imparts a rotational motion rotates a piston having a thread groove to generate a pumping pressure, and pumps the application fluid to the discharge side.
The combination of the above (1) and (2) realizes the high-speed blocking / high-speed opening control of the coating line at the boundary between the effective display area and the non-effective display area.
[0130]
In FIG. 16, reference numeral 101 denotes a first actuator. In this embodiment, a giant magnetostrictive element that can obtain high positioning accuracy, has high responsiveness, and obtains a large generated load is used. Reference numeral 102 denotes a main shaft (piston) driven by the first actuator 101. The first actuator is housed in a housing 103, and a pump portion 104 that houses the main shaft 102 is attached to a lower end portion (front side) of the housing 103.
[0131]
Reference numeral 105 denotes a second actuator, which gives a relative rotational movement between the main shaft 102 and the housing 103. The motor rotor 106 is fixed to the upper main shaft 107, and the motor stator 108 is accommodated in the upper housing 109. 111 and 112 are cylindrical rear-side giant magnetostrictive rods and front-side giant magnetostrictive rods composed of giant magnetostrictive elements. Reference numeral 113 denotes a magnetic field coil for applying a magnetic field in the longitudinal direction of the giant magnetostrictive rods 111 and 112. Reference numerals 114, 115, and 116 denote rear, middle, and front permanent magnets for applying a bias magnetic field to the giant magnetostrictive rods 111 and 112. The rear side and front side permanent magnets 114 and 116 are arranged so as to sandwich the giant magnetostrictive rods 111 and 112 and the intermediate permanent magnet 115. The permanent magnets 114 to 116 increase the operating point of the magnetic field by applying a magnetic field to the giant magnetostrictive rods 111 and 112 in advance, and this magnetic bias can improve the linearity of the giant magnetostriction with respect to the strength of the magnetic field.
[0132]
117 is disposed on the rear side of the giant magnetostrictive rod 111, the rear side yoke being a yoke material of the magnetic circuit, 118 is disposed on the front side of the giant magnetostrictive rod 112, and the front side sleeve also serving as the yoke material is designated 119, which is a magnetic field coil 13 is a cylindrical yoke material disposed on the outer peripheral portion of 13.
[0133]
112 → 115 → 111 → 114 → 117 → 119 → 118 → 116 → 112 forms a closed loop magnetic circuit for controlling expansion and contraction of the giant magnetostrictive rods 111 and 112. The main shaft 102 is made of a nonmagnetic material so as not to affect the magnetic circuit. That is, the giant magnetostrictive rods 111 and 112, the magnetic field coil 113, the permanent magnets 114 to 116, the rear side yoke 117, the front side sleeve 118, and the yoke material 119 are used to control the expansion and contraction of the giant magnetostrictive rod in the axial direction by the current applied to the magnetic field coil. A possible giant magnetostrictive actuator (first actuator 101) is configured.
[0134]
A rear sleeve 120 accommodates the upper main shaft 107 so as to be rotatable and movable in the axial direction. The rear sleeve 120 is also supported by the bearing 139 so as to be rotatable with respect to the intermediate housing 121.
[0135]
Reference numeral 122 denotes a bias spring mounted between the rear yoke 117 and the rear sleeve 120. Due to the axial load applied from the bias spring 122, the giant magnetostrictive rods 111 and 112 are held in such a manner that they are pressed against the upper and lower rear yokes 17 and the front sleeve 18 through the bias permanent magnets 114 to 116. . As a result, since compressive stress is always applied to the giant magnetostrictive rods 111 and 112 in the axial direction, the drawback of the giant magnetostrictive element that is weak against tensile stress is eliminated when repeated stress is generated.
[0136]
The front-side sleeve 118 accommodates the main shaft 102 so as to be movable in the axial direction. The rotational power of the main shaft 102 transmitted from the motor 105 is transmitted to the front side sleeve 118 by a rotation transmission key 123 provided between the main shaft 102 and the front side sleeve 118. The front sleeve 118 is also rotatably supported by the housing 103 by a bearing 124.
[0137]
With the above configuration, the rotational power of the motor 105 is transmitted only to the main shaft 102 and the front sleeve 118, and no torsion torque is generated in the giant magnetostrictive element that is a brittle material.
[0138]
Further, the giant magnetostrictive elements 111 and 112 and the permanent magnets 114 to 116 formed in a ring shape are arranged so as to penetrate the main shaft 2 of a nonmagnetic material. Further, the gap between the outer peripheral portion of the main shaft 102 and the inner peripheral portion of the giant magnetostrictive rod and the permanent magnet is set to be sufficiently small. As a result, the shafts of the giant magnetostrictive rod and the permanent magnet do not deviate greatly due to the influence of the centrifugal force applied to each member during the rotation of the apparatus.
[0139]
That is, the main shaft 2 provided through each member has both a “protective function” that gives only the compressive stress to the giant magnetostrictive element, which is a brittle material, and a “preventive function of axial misalignment” during rotation. ing.
[0140]
Reference numeral 125 denotes an encoder for detecting rotational position information of the upper main shaft 7 disposed on the upper portion of the motor 105 which is the second actuator. Reference numeral 126 denotes a displacement sensor for detecting the axial displacement of the upper end surface 127 of the upper main shaft 7 (and the main shaft 102).
[0141]
With the above-described configuration, it is possible to realize a “two-degree-of-freedom / composite operation actuator” that can simultaneously and independently control the rotational movement and the linear movement of minute displacement. Furthermore, in this embodiment, since the giant magnetostrictive element is used for the first actuator, power for linearly moving the giant magnetostrictive rods 111 and 112 (and the main shaft 102) can be applied from the outside without contact.
[0142]
Since the input current applied to the giant magnetostrictive element and the displacement are proportional, the axial positioning control of the main shaft 102 is possible even in open loop control without a displacement sensor. However, if the position detection means as in the present embodiment is provided and feedback control is performed, the hysteresis characteristics of the giant magnetostrictive element can be improved, so that positioning with higher accuracy can be performed.
[0143]
In the present embodiment, the size of the gap on the discharge side end face of the main shaft can be arbitrarily controlled using the axial positioning function of the main shaft 102 while maintaining the steady rotation state of the main shaft. Using this function, it is possible to control the shutoff / opening of the powder fluid at the start and end in a state where any flow path section from the suction port 132 to the discharge nozzle 133 is mechanically non-contact.
[0144]
Reference numeral 128 denotes a radial groove for pumping the fluid formed on the outer surface of the main shaft 2 to the discharge side, 129 is a fluid seal, and 130 is a cylinder. A pump chamber 131 (fluid transport chamber) for obtaining a pumping action is formed between the main shaft 102 and the cylinder 130 by relative rotation of the main shaft 102 and the cylinder 130. Further, the cylinder 130 is formed with a suction hole 132 communicating with the pump chamber 131. Reference numeral 133 denotes a discharge nozzle attached to the lower end of the cylinder 130, and 134 denotes a discharge plate fastened to the discharge side end face of the cylinder 130. Reference numeral 135 denotes a thrust plate attached to the discharge side end face of the main shaft 102.
[0145]
The radial groove 128 which is a fluid pressure feeding means is a known one known as a spiral groove dynamic pressure bearing and is also used as a thread groove pump.
[0146]
Now, in the present embodiment, the main shaft 102 (hereinafter referred to as “piston”) driven by the giant magnetostrictive element can perform high-speed linear motion simultaneously with rotation, and the following method is used for the start and end of the coating line. We tried to solve the problem.
[0147]
(1) At the start of application, the piston is rapidly lowered and simultaneously the motor starts to rotate.
[0148]
(2) At the end of coating, the piston is raised and the motor is stopped.
[0149]
In this embodiment, since the piston is driven by the giant magnetostrictive element, the response of the output displacement to the input signal of the piston is 10 ^-3 The order was sec (1000 Herz). Since the time delay between the generation of the squeeze pressure with respect to the change in the gap is very small, the responsiveness of the flow rate control is extremely high.
[0150]
In this embodiment, the overshoot pressure and suck back pressure for smoothly drawing the start point and end point of the coating line can be obtained by the axial movement of the piston. In the present embodiment, the piston displacement curve (an example is shown in FIG. 7) can be set to an arbitrary shape. In addition, since the giant magnetostrictive element that drives the piston has high responsiveness, it can sufficiently follow even if the displacement curve changes sharply. That is, by controlling the displacement and speed of the giant magnetostrictive element, it is possible to control the discharge pressure and flow rate at the delicate start and end, which cannot be achieved by controlling the rotational speed of the motor.
[0151]
In the present embodiment, the problem of the start and end of the continuous coating line is solved by combining the control of the axial displacement of the giant magnetostrictive element and the control of the rotational speed of the motor, and material leakage from the discharge nozzle in the U-turn section. It was possible to keep a complete shut-off state for any time. When the U-turn section can be set sufficiently short, the flow rate can be shut off at the end point and opened at the start point by driving only the piston while maintaining the rotation of the motor.
[0152]
In the present embodiment of FIG. 16, the displacement sensor 126 is disposed at the upper end of the main shaft 102 in order to detect the axial position of the main shaft (piston) 102. The role of the displacement sensor 126 is to control the gap (corresponding to h in FIG. 1) between the discharge-side end surface of the main shaft 102 and its opposing surface. However, since the distance between the displacement detection part and the discharge side end face of the main shaft is long, there is a concern about the influence of the thermal expansion of the member on the gap.
[0153]
For example, the distance between the upper end of the spindle and the end surface on the discharge side is L = 200 mm, and the thermal expansion coefficient α = 13 × 10. ^-6 Assuming that the temperature difference between the main shaft and the housing is ΔT10 ° C., the variation Δh of the gap h between the discharge side end surface and the opposing surface is
[0154]
[Expression 15]

[0155]
Δh is a drift component that cannot be controlled.
[0156]
However, the fluid supply means has a sufficiently large internal resistance R _s And the gap h is sufficiently large (for example, in FIG. _min = 150 μm), it is possible to realize a head configuration in which the gap variation does not affect both the continuous discharge amount and the blocking performance.
[0157]
In the present embodiment, since the discharge blocking performance uses a secondary squeeze action, it is not the absolute value of the gap h but the maximum differential value V of the gap. _max Determined by. Therefore, it is not affected by the displacement drift (Equation 9).
[0158]
In this embodiment, the pump unit is configured by giving the piston both a function of axial movement and rotation by a two-degree-of-freedom actuator using a giant magnetostrictive element. Instead of this configuration, for example, a rotating shaft (outer peripheral piston) that does not move in the axial direction is formed into a cylindrical shape, a central shaft (inner peripheral piston) is inserted into this rotating shaft, the rotating shaft is driven by a motor, The shaft may be driven in the axial direction by an electrostrictive element or the like installed on the fixed side. In this case, by increasing or decreasing the gap between the discharge side end surface of the inner peripheral side piston and the opposing surface, the flow rate can be shut off at the end point and opened at the start point. In short, it is only necessary to increase or decrease the space of the fluid transport chamber. Further, if a thread groove is formed in the outer peripheral side piston and a fixed relative movement surface for housing the outer peripheral side piston, it can be used as a fluid pressure feeding means (not shown).
[0159]
When there is an obstacle (for example, a wall) on the outer peripheral portion (363 in FIG. 22) of the display panel, the entire length of the discharge nozzle 133 may be made long as long as the obstacle does not contact the main body of the dispenser. A pipe is attached to the discharge plate, and a discharge nozzle tip having an appropriate inner diameter and length may be attached to the lower end of the pipe.
[0160]
Moreover, the thread groove pump which is a fluid conveyance means is not an essential condition for implementing the present invention. The fluid may be supplied to the pump chamber 131 by using a pressure source (pump) installed outside. In this case, it is not necessary to form a thread groove in the piston. For example, when a gear pump installed outside is used for the fluid pressure feeding means and the U-turn section can be set sufficiently short, the flow rate cut-off and release control at the start and end points can be controlled by driving only the piston. Good.
[0161]
In addition, when applying a powder fluid such as a phosphor or electrode material containing fine particles, the minimum value δ of the gap δ _min May be set larger than the fine particle diameter φd.
[0162]
[Expression 16]

[0163]
If the above-described viscous thread groove pump is used as the fluid replenishing means, it is possible to configure a flow path without any mechanical contact portion from the fluid supply source to the discharge nozzle. It is advantageous to transport.
[0164]
When a highly viscous fluid is discharged, it is expected that extremely large fluid pressures are generated for both the pumping pressure and the squeeze pressure. In this case, since the first actuator that drives the piston is required to have a large thrust against a high fluid pressure, it is effective to apply an electromagnetic strain actuator that can easily generate a force of several hundred to several thousand N. is there. Since the magnetostrictive element has a frequency response of several MHz or more, the main axis can be linearly moved with high response. Therefore, the discharge amount of the high-viscosity fluid can be controlled with high response and high accuracy.
[0165]
In addition, when a giant magnetostrictive element is used for the axial direction driving means, a conductive brush can be omitted as compared with the case where a piezoelectric element is used. Therefore, the load on the motor (rotating means) can be reduced and the overall configuration becomes extremely simple. Therefore, the moment of inertia of the moving part can be minimized and the diameter of the dispenser can be reduced.
[0166]
In the present embodiment, the minimum clearance between the piston and its opposing surface is h. _min = 150 μm. The particle size of the phosphor of this embodiment is φd = 7-9 μm, h _min >> Because φd, the fine particles of the phosphor are not mechanically squeezed or damaged in the passage from the suction port to the discharge port.
[0167]
When this invention was used for electrode formation of a PDP surface plate, the particle size of the silver paste was 0.1 to 1 μm. Although the particle diameter is smaller than that of the fine particles of the phosphor, consideration must be given to improving the fluidity inside the pump of the electrode material having a large specific gravity. Even in this case, the minimum clearance of the piston portion is, for example, h _min The head of the present invention which can be formed to> 150 μm is extremely advantageous in terms of reliability for preventing clogging. In the case of the PDP surface plate, the terminal end (or start end) of the electrode wire must be blocked at the boundary between the terminal portion and the bus electrode portion, but the same method as the phosphor coating described in the present embodiment can be used. In addition, when the line width of the electrode wire varies depending on the location, if a thread groove type is used for the fluid supply means, the flow rate is proportional to the rotation speed, so the rotation speed and the stage speed may be set according to the line width.
[0168]
FIG. 17 shows a second embodiment of the present invention, and shows a case where a thread groove pump as a fluid replenishing means and a piston for generating a primary squeeze pressure are separated. A main shaft 51 is housed so as to be movable in the rotational direction with respect to the housing 52. The main shaft 51 is rotationally driven by a rotation transmitting means (arrow 53). Reference numeral 54 denotes a thread groove (blackened portion) formed on the relative movement surface of the main shaft 51 and the housing 52, and 55 denotes a fluid suction port.
[0169]
56 is an axial driving means for moving the piston 57 in the axial direction (arrow 58), 59 is an end face of the piston 57, 60 is a fixed-side facing surface, and 61 is a discharge nozzle mounted on the housing 52. The piston end surface 59 and the fixed-side facing surface 60 form two surfaces (discharge chambers) that relatively move in the gap direction. 62 is a main shaft end, 63 is a piston outer peripheral portion, and 64 is a flow passage connecting the main shaft end 62 and the piston outer peripheral portion 63.
[0170]
The application fluid 65 is always supplied to the piston outer peripheral portion 63 through the flow passage 64 by a thread groove pump 54 that is a fluid supply means. The axial direction drive means 56 (specific structure is not shown) gives a change in relative position in the axial direction between the piston 57 and the housing 52 on the fixed side. The axial direction driving means 56 changes the gap h between the piston end surface 59 and the opposing surface 60 in the same manner as the embodiment shown in FIG. 16 or the model shown in FIG. Also, the configuration conditions of the thread groove pump and the piston are the same,
(1) The minimum value of the clearance h on the piston end face is h = h _min When h _min Is sufficiently large, for example h _min > H _x1 (E.g. h _x1 ≈40 μm).
[0171]
(2) The thread groove is designed close to the metering pump, and its internal resistance R _s Is big enough.
[0172]
As shown in the second embodiment, if a coating device is configured by separating a pump portion 66 that is a fluid replenishment means and a portion (piston drive portion 67) that drives a piston by an axial direction drive means, an object to be applied Depending on the case, the device can be made compact and simple. For example, if the piston drive unit is configured by using a piezoelectric element for the axial direction drive means, the piezoelectric element actuator can be made sufficiently compact, so that the entire apparatus can be greatly simplified in the case of a multi-head described later.
[0173]
The perspective view of FIG. 18 shows a third embodiment of the present invention, in which the pump part which is a fluid replenishing means and the piston drive part are connected by a flexible tube, the pump part is arranged on the fixed side, and the piston drive The part is arranged on the stage side that travels at a high speed. In this case, since the piston drive unit may be light, it is advantageous for high-speed speed control / positioning control of the discharge nozzle tip with respect to the panel.
[0174]
In FIG. 18, reference numeral 150 denotes a panel, and a pair of Y-axis direction conveying devices 151 and 152 are provided with both sides of the panel interposed therebetween. Further, an X-axis direction transport device 153 is mounted on the Y-axis direction transport device so as to be movable in the YY ′ direction.
[0175]
Further, a Z-axis direction conveyance device 154 is mounted on the X-axis direction conveyance device so as to be movable in the arrow XX ′ direction. The Z-axis direction transport device 154 is equipped with a piston drive unit 155 composed of a piezoelectric actuator and a piston.
[0176]
A pump unit 156 is a fluid replenishing unit, and is arranged on the fixed side. Reference numeral 157 denotes a flexible tube which is a flow path connecting the pump unit 156 and the piston driving unit 155.
[0177]
[4] Other application examples: Multi-head
All of the embodiments of the dispenser described above are single heads in which a pump part and a piston driving part which are fluid replenishing means are configured as a pair.
[0178]
Hereinafter, a measure for further improving the production tact of the head of the present invention will be described.
[0179]
Even when a phosphor layer, a silver paste electrode material, or the like is formed on the panel surface using a dispenser, a production tact equivalent to that of the screen printing method is desired.
[0180]
When the present invention is applied to, for example, the phosphor coating of the PDP back plate and the electrode forming process of the front plate, the following conditions are necessary in addition to the above-described coating process conditions.
[0181]
(1) Multi-head
(2) The flow rate of each head can be corrected.
The reason for (2) above will be described below. As shown in the second embodiment (FIG. 16), if a coating device is constructed by separating the pump as the fluid replenishing means and the axial driving means for driving the piston, a plurality of pump units from one set of the pump unit are provided. A coating head having multiple nozzles can be realized by branching and replenishing fluid to the piston drive section.
[0182]
In the arrow view of FIG. 19, reference numeral 200 denotes a pump unit that is a fluid replenishing means, and 201, 202, and 203 denote piston drive units A, B, and C each including a piezoelectric actuator and a piston. Reference numeral 204 denotes a housing in which a flow passage (corresponding to 64 in FIG. 17) connecting the pump unit 200 and the piston drive unit is formed.
[0183]
Normally, there is a limit to downsizing of the pump part which is a fluid replenishment means, but the piston drive part can be applied with a small-diameter piezoelectric actuator or the like, and when using a multi-head configuration, the pitch between nozzles can be made sufficiently small. .
[0184]
The multi-head shown in FIG. 19 may be used as a subunit, and a coating apparatus in which a plurality of subunits are combined may be used.
[0185]
FIG. 20 shows an equivalent circuit model in the case of a multi-head.
[0186]
P _squ11 , P _squ12 , P _squ13 Is the primary squeeze pressure of each piston drive, R _p1 , R _p2 , R _p3 Is the fluid resistance in the radial direction of the piston end face, R _n1 , R _n2 , R _n3 Is each nozzle resistance. R _p1 ~ R _p3 Is inversely proportional to the cube of the gap h, as shown in (Equation 8). Ie R _p1 ~ R _p3 Is a “variable resistor” that can individually adjust the flow rate of each head without disassembling the coating device.
[0187]
In the embodiment of the single head described above, the total reverse flow rate Q is set by setting the gap h of the piston end face sufficiently large and suppressing the generation of the primary squeeze pressure as much as possible. _s Or the discharge nozzle upstream pressure P _i Does not depend on the size of the gap h, and is determined only by the condition setting (for example, the rotational speed) of the pump unit. When fluid is branched and replenished from a set of pump units to a plurality of piston drive units, the flow rate supplied from the pump unit is as long as the dimensional accuracy and flow path resistance of each piston drive unit can be configured to be exactly the same. It is distributed equally. However, it is practically difficult for a coating object such as a display that requires accuracy of a coating amount of several percent.
[0188]
In the present embodiment, the minimum gap h of each piston _min By individually adjusting the variable resistance R _p1 ~ R _p3 The flow rate can be adjusted without disassembling the coating apparatus.
[0189]
Minimum clearance h _min If the set value is too large, the minimum gap h _min Even if this is changed, the effect on the flow rate is reduced, so that it is difficult to adjust the flow rate. From the graph of FIG. 13, the minimum gap h _min Is 0 <h _min <H _x2 It may be set so as to enter the area. Alternatively, if the flow rate difference between the heads is sufficiently small, the gap h _min The curve of flow rate with respect to has a gentle characteristic _min ≒ h _x2 The flow rate may be finely adjusted using the vicinity.
[0190]
The displacement of the piston can be arbitrarily controlled by providing a displacement sensor for detecting the absolute position of the piston and performing closed loop control. However, when an electromagnetic strain element such as a piezoelectric element or a giant magnetostrictive element is used, there is a stroke limit (0 to several tens of microns). _min The adjustment may be performed using a combination of a mechanical method and an electronic control method. For example, after the position of the piston is first mechanically coarsely positioned, the piston position of each head may be corrected again using electronic control based on flow rate measurement data.
[0191]
Even when the above method is used for flow rate adjustment, the flow rate can be adjusted where the piston end face clearance is sufficiently large if used in combination with the method for setting the output flow rate of the supply pump. For example, if the flow rate is too high, the minimum piston gap h _min If the rotational speed of the thread groove pump is reduced, h _min Can be set larger. As will be described later, this point is advantageous when handling powder fluid.
[0192]
The above-mentioned measures used for correcting the flow difference between the heads of the multi-head can be applied to the case of a single head. In either case of single head or multi head, instead of changing the motor speed of the pump, h _min By adjusting, high-speed flow control can be performed. The responsiveness of the rotational speed control of the motor is at most 0.01 to 0.05 second level, and there is a limit, but the control responsiveness of the piston driven by the electromagnetic strain element can be up to 0.001 second or less. Also, the minimum piston clearance h _min The flow rate may be adjusted by the average value or the center value of the piston input displacement waveform, instead of adjusting the flow rate by.
[0193]
The form of the pump as the fluid replenishing means in the present invention is not limited to the thread groove type, and other types of pumps can be applied. For example, a Mono type, a gear type, a twin screw type, a syringe type pump or the like called a snake pump can be applied.
[0194]
FIG. 21 is a model diagram when a gear type is used as the fluid replenishing means in the present invention, where 700 is a gear pump, 701 is a flow passage, 702a, 702b, and 702c are axial driving means constituted by, for example, a piezoelectric actuator. , 703a, 703b, and 703c are pistons.
[0195]
Maximum flow rate Q of the pump _max Maximum pressure P _max Usually, it is often obtained theoretically, but if it is difficult, it may be obtained experimentally.
[0196]
Internal resistance R of the pump _s Is the pressure and flow rate at the operating point P _i , Q _i If the pressure and flow rate are slightly changed near the operating point, R _s = ΔP _i / ΔQ _i May be actually measured. Alternatively, the relationship between the pump flow rate and pressure is measured, and the slope of the characteristic curve at the operating point: ΔP _i / ΔQ _i The internal resistance may be obtained from Fluid resistance R in the flow path leading to the pump and piston end faces _s2 If there is, the internal resistance R of the pump _s Value added to: R _s0 = R _s + R _s2 Is defined as the fluid internal resistance of the fluid transportation means, and the above-described theory may be used. This fluid resistance R _s2 May be theoretically obtained from, for example, a well-known theoretical formula (for example, (Formula 7), (Formula 8)). Or you may obtain | require experimentally.
[0197]
Fluid resistance R _n , R _p Is similarly obtained from (Equation 7) and (Equation 8). However, if the shape is complicated, numerical analysis may be used or may be obtained experimentally. In the case of an orifice whose throttle part length is short with respect to the inner diameter, the linear resistance equation (for example, (Equation 7)) does not hold, but in this case, if the linearization is performed around the operating point to make the apparent fluid resistance, Good.
[0198]
The shape of the piston that constitutes the piston drive unit and its opposing surface may not be circular. The piston may be rectangular. In this case, the radius of a circle having an equivalent area is taken as the average radius. In the pump of this embodiment that handles a minute flow rate, the stroke of the piston may be on the order of several tens of microns at most, and even if an electromagnetic strain element such as a giant magnetostrictive element or a piezoelectric element is used, the limit of the stroke does not matter.
[0199]
If responsiveness is sacrificed, a moving magnet type, a moving coil type linear motor, an electromagnetic solenoid, or the like may be used as the axial direction driving means for driving the piston. In this case, the stroke restriction is eliminated (not shown).
[0200]
In the above description, only continuous coating has been described. However, the structure of the coating apparatus disclosed in [3] Specific Embodiment or [4] Multi-Head is applicable even in the case of intermittent coating. That is, it is possible to use both continuous application and intermittent application in the same application apparatus.
[0201]
【The invention's effect】
If the present invention is applied to, for example, phosphor coating of a display, electrode layer formation, etc., a screen stripe can be applied to a substrate of any size by simply setting numerical values of the substrate without using a conventional screen mask. Can be formed with high accuracy and can easily cope with a change in the specifications of the substrate. In addition, since it can cope with high-speed processes, there is no inferior production tact in comparison with the conventional method, and there is no material to be discarded, so that material loss can be greatly reduced.
[0202]
It is not necessary to increase the scale of the manufacturing process and the production line, and it is possible to screen with a single device, and to produce a mass production effect for a display panel of high-mix low-volume production. Automation lines can be run on small machines.
[0203]
The present invention can be used in production processes of semiconductors, surface mounts, liquid crystals, transparent touch panels, organic ELs, sheet devices and the like other than display panels such as PDPs, and the effects are enormous.
[Brief description of the drawings]
FIG. 1 is a model diagram illustrating the principle of the present invention.
FIG. 2 is a diagram showing piston displacement with respect to time
FIG. 3 is a diagram showing thread groove pressure against time
FIG. 4 is a diagram showing squeeze pressure against time.
FIG. 5 is a diagram showing discharge nozzle upstream pressure with respect to time
FIG. 6 is a detailed view of the discharge section of FIG.
FIG. 7 is a diagram showing piston displacement with respect to time
FIG. 8: Internal resistance R _s Electric circuit model diagram when is small enough to be ignored
FIG. 9 is a diagram showing the discharge nozzle upstream pressure with respect to time.
FIG. 10 shows internal resistance R _s Electric circuit model diagram for large
FIG. 11 is a diagram showing discharge nozzle upstream pressure with respect to time
FIG. 12 is a graph showing the relationship between the total reverse flow rate and the minimum piston clearance.
FIG. 13 is a graph showing the relationship between the discharge nozzle upstream pressure and the minimum piston clearance.
FIG. 14: Fluid resistance R _p , R _s Of relationship between piston and minimum piston clearance
FIG. 15 is a schematic perspective view when the present invention is applied to a phosphor layer device of a PDP panel.
FIG. 16 is a front sectional view showing the dispenser according to the first embodiment applied to the present invention.
FIG. 17 is a front sectional view showing a dispenser according to a second embodiment applied to the present invention.
FIG. 18 is a front sectional view showing a dispenser according to a third embodiment applied to the present invention.
FIG. 19 is a model diagram when the present invention is applied to a multi-head.
FIG. 20 is a diagram showing an electric circuit model in the case of a multi-head.
FIG. 21 is a model diagram of the fluid supply means of the present invention when a thread groove pump is used.
FIG. 22 is a diagram showing an effective display area and an ineffective display area on the panel surface;
FIG. 23 shows a conventional air dispenser.
FIG. 24 is a schematic perspective view of a conventional dispenser-type phosphor layer coating apparatus.
[Explanation of symbols]
1 piston
2 Housing
5 Thread groove
6 Suction port
7 Lower plate
8 End face
9 Fixed side facing surface of the end face
10 Discharge nozzle
11 opening
12 Coating fluid
13 Outer periphery of piston end face
14 Gap
15 upstream
16 Fluid transport chamber

Claims (1)

Formed by the cylinder and the piston, and supplies the fluid to the fluid transport chamber and the suction hole inlet and the discharge nozzle is contacted, giving a relative axial movement between said piston and said cylinder, said at the start of the coating Pattern formation in which the fluid is continuously applied and formed from the discharge nozzle by reducing the gap h formed between the discharge-side end surface of the piston and the opposing surface, and increasing the gap h at the time of application interruption when compared with the start of application. In the method
The fluid resistance between the outer circumferential portion and the suction port of the piston end surface Rs, when the fluid resistance of the radial flow path before Kisuki between h was Rp, when continuously applied form the fluid , while keeping larger than 50μm the gap h holds the relationship between the Rs and Rp while rotating the piston to Rs> Rp, at the time of application blocking is characterized by stopping the rotation of the piston pattern Forming method.

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