JP2004311094A - Electron source substrate manufacturing apparatus, electron source substrate, and image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electron source substrate manufacturing apparatus which can manufacture a high-quality and reliable electron source substrate having electron emitters. <P>SOLUTION: The electron source substrate manufacturing apparatus injects a solution containing a fine metal particle material for forming a conductive thin film between element electrodes on a substrate with an injection head to form a group of surface conduction type electron emitters. An electron emitting part of the surface conduction type electron emitters is formed by a dot pattern of the solution, the element electrodes are constituted by a rectangular pattern or a combination of the rectangular patterns, and a corner part of the rectangular pattern is formed in a chamfered shape. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００６０】
これらのサンプル溶液および噴射ヘッドを使用して評価した結果を下記表２〜５に示す。表中、キズの○は１００時間噴射後に、目立ったキズが確認できなかったもの、×はノズル形状、あるいは寸法にまでも影響をおよぼすような多数のすりキズが存在したものである。素子形状の○は１００時間噴射後に、素子を作製した際の、ドットパターンが、狙いの位置（一対の電極間）に良好な丸い形状で形成されたものであり、×は位置がやや狙いの場所から外れていたり、形状がいびつであったり、微小滴が周囲に飛散していたりしたものである。素子性能の○×は後述のフォーミング処理等を行った後の電子放出の良（○）否（×）である。
【００６１】
【表２】

【００６２】
【表３】

【００６３】
【表４】

【００６４】
【表５】

【００６５】
以上の結果より、含有金属微粒子の硬度が、吐出口材質より大であるもの（Ｓ３、Ｓ６）の場合、吐出口に傷がつくことがわかる。またそれによって形成された素子形状は悪く、素子性能も悪いことがわかる。よって、本発明のような製造装置によって、このような表面伝導型電子放出素子を形成する場合には、金属微粒子は吐出口を構成する部材よりやわらかい材料を選ぶ必要があることがわかる。
【００６６】
なおそのキズに関しては、吐出口の大きさとの関係で、素子形状が悪くならないものもある。参考ヘッドのように、吐出口径がΦ３６μｍもある（＝面積が約１０００μｍ^２）ような場合には、キズはついても吐出口径が大きいために、噴射性能を劣化に至らしめるほどのキズではなく、十分に使用可能な素子形状が得られている。
【００６７】
一方、吐出口径がΦ２５μｍ以下（＝面積が約５００μｍ^２未満）の場合のように、面積比較で参考ヘッドの半分以下のような場合には、同じようにキズがついても、吐出口径との比較において与える影響は大であり、良好な素子形状、素子性能が得られないことがわかる。
【００６８】
つまり、それほど微細な表面伝導型電子放出素子を形成しないのであれば、キズの問題は素子性能に影響を与えないので気にすることはないが、本発明のように、吐出口径Φ２５μｍ以下の液滴噴射ヘッドにより、１０Åないし２００Åの金属微粒子を含有する溶液を噴射付与し、導電性薄膜による表面伝導型電子放出素子群を形成するような場合には、吐出口部のキズは、素子性能にとって致命的であるので、キズができないような溶液および吐出口部材の組み合わせを選ぶ必要がある。すなわち、金属微粒子は吐出口を構成する部材よりやわらかい材料とする必要がある。
【００６９】
なお実験では、丸形状のΦ２５μｍノズル（面積が約４９０μｍ^２）、Φ１６μｍノズル（面積が約２００μｍ^２）、Φ１０μｍノズル（面積が約８０μｍ^２）を使用したが、噴射ヘッドのノズルとして他の形状（たとえば矩形等）のものを使用する場合には、その面積比較をすればよく、たとえば、２２μｍ×２２μｍのノズルが、本発明の丸形状のΦ２５μｍノズルと同等である。言い換えるならば、本発明は面積が５００μｍ^２未満のノズルを使用した噴射ヘッドで、このような溶液を噴射して表面伝導型電子放出素子群を形成する場合に適用されるものである。
【００７０】
次に、本発明の他の特徴について説明する。前述のように本発明では、導電性薄膜を形成するための材料を含有する溶液は、液体に金属微粒子を分散させた溶液である。そして、いわゆるインクジェット噴射原理と同等の技術でその溶液を微細な吐出口から噴射して、基板上に導電性薄膜を形成する技術に関するものである。しかしながら従来インクジェット記録分野で使用しているインクでは染料が溶液中に溶解しているのに対して、本発明で使用する溶液は金属微粒子は溶液中に分散しているだけなので、目詰まりが起こりやすい。
【００７１】
さらに、本発明では、必要とされる素子（電子放出素子）の用途から、従来にはない微細な吐出口径、例えば、吐出口径がΦ２５μｍ以下（面積でいうならば５００μｍ^２未満）であるような噴射ヘッドを使用しなければならず、この目詰まりは大変深刻な問題である。
【００７２】
ところで目詰まりとは、微細な吐出口から溶液が噴射するという原理そのものに由来するものである。つまり、吐出口が微細であるがゆえに生じるものである。よってその吐出口の大きさと、いわば溶液中の異物とでもいうべき金属微粒子の大きさには密接な関係がある。
【００７３】
本発明はこの点に鑑み、吐出口の大きさと金属微粒子の大きさに着目し、目詰まりの生じにくさとそれらの関係を見い出したものである。具体的には金属微粒子径を変えた溶液を調合し、吐出口の大きさがわかっている噴射ヘッドを使用し、一定時間液滴噴射を行った後、一定時間放置し、液滴噴射を再開し、吐出口の目詰まりの有無を調べた。その場合、吐出口の完全閉塞だけではなく、部分的な目詰まりおよびそれに至る事前の兆候（わずかな目詰まり）も目詰まりとみなしてテストした。
【００７４】
使用した噴射ヘッドは、熱エネルギーを使用するサーマルインクジェット方式と同等のものであり、前述のように図６の噴射ヘッドに、ノズルプレートを装着したもの（ノズルプレートは図示せず）であるが、図６に示したものは、説明を簡単にするため吐出口を４個しか示していない。実際に使用したのは吐出口の数が１２８個で、その配列密度が６００ｄｐｉのものである。また、発熱体の大きさは２０μｍ×８５μｍで、その抵抗値は１０５Ωであり、液滴噴射の駆動電圧は２２Ｖ、駆動パルス巾は６μｓ、駆動周波数は１４ｋＨｚとした。
【００７５】
なお、記録ヘッドはＨ１〜Ｈ４まで用意した（それぞれの吐出口径をＨ１＝Φ２５μｍ、Ｈ２＝Φ２０μｍ、Ｈ３＝Φ１５μｍ、Ｈ４＝Φ１０μｍとした）。また、そのノズルプレートはＮｉのエレクトロフォーミングによって形成したものであり、吐出口部分の板厚は、全て３０μｍとした。
【００７６】
使用した溶液は、パラジウム微粒子を電圧６０Ｖ、周波数５０Ｈｚ、酸素流量４０ｍｌ／ｍｉｎのオゾン発生装置でオゾン処理し、その処理済みのパラジウム微粒子７ｇをエチレングリコール５ｇ、エタノール８ｇ、純水８０ｇの溶液に分散させ、噴射用溶液としたものであるが、パラジウム微粒子径を０．０００３〜０．５μｍまで変えたものを準備し、吐出口径の異なるＨ１〜Ｈ４と組み合わせてテストした。また、一定時間（１０分間とした）液滴噴射を行った後の放置の条件は、温度４０℃、湿度３０％の雰囲気中で１０時間放置である。
【００７７】
これらのパラジウム微粒子径を変えた溶液と吐出口径を変えたヘッドＨ１〜Ｈ４を組み合わせて、目詰まりの発生状況を調べた結果を下記表６〜表９に記す。なお、表６はヘッドＨ１（吐出口径Ｄｏ＝Φ２５μｍ）の場合、表７はヘッドＨ２（吐出口径Ｄｏ＝Φ２０μｍ）の場合、表８はヘッドＨ３（吐出口径Ｄｏ＝Φ１５μｍ）の場合、表９はヘッドＨ４（吐出口径Ｄｏ＝Φ１０μｍ）の場合を示す。判定の○は実用的に良好に使用できる場合、△は使うことは可能であるがあまり好ましくない場合、×は全く実用的ではない場合を示している。なお、パラジウム微粒子径が０．０００５μｍ以下の場合は、安定的に分散させることができなくて、評価はできなかった。
【００７８】
【表６】

【００７９】
【表７】

【００８０】
【表８】

【００８１】
【表９】

【００８２】
以上の結果より、吐出口径がΦ１０μｍ〜Φ２５μｍの噴射ヘッドを用いた場合、パラジウム微粒子径Ｄｐと吐出口径Ｄｏとは、Ｄｐ／Ｄｏ≦０．０１の関係を満足するようにすれば目詰まりのない安定した液滴噴射が得られることがわかる。
【００８３】
なお、Ｄｐ／Ｄｏの下限値であるが、このように大変微細な金属微粒子を安定して、溶液中に分散することを考えると、パラジウム微粒子径Ｄｐが０．０００５μｍ以下は困難である。また、吐出口径がΦ２５μｍ以下の噴射ヘッド全てに安定して液滴噴射させられるようにするには、余裕をみてその下限値を０．０００１にすればよい。
【００８４】
すなわち、金属微粒子径Ｄｐと吐出口径Ｄｏとは、０．０００１≦Ｄｐ／Ｄｏ≦０．０１の関係を満足するようにすれば、吐出口径がΦ２５μｍ以下の噴射ヘッドを使用した液滴噴射による導電性薄膜形成を行うことができる安定した分散液を製造でき、目詰まりも生じないようにすることができることがわかる。
【００８５】
なおこの実験でも、丸形状の吐出口（ノズル）を使用したが、前述のように、他の形状の場合は、その面積比較をすればよく、たとえば、２２μｍ×２２μｍの矩形吐出口の場合は、本発明の丸形状のΦ２５μｍノズルと同等である。言い換えるならば、本発明は面積が５００μｍ^２未満のノズルを使用した噴射ヘッドで、このような溶液を噴射して表面伝導型電子放出素子群を形成する場合に適用されるものである。
【００８６】
また実験はサーマルインクジェット（バブルジェット（登録商標））方式の噴射ヘッドを使用したが、本発明の製造装置に使用される噴射ヘッドはこれに限定されることなく、圧電素子を用いたピエゾジェット方式、静電力を利用した方式、あるいは荷電制御方式（連続流方式）等いずれのものでも構わない。
【００８７】
例えば圧電素子を用いたピエゾジェット方式の場合、ピエゾ素子への入力電圧をいつも一定にすることにより液滴飛翔時に丸い均一滴が得られ、基板上で良好な丸いドットが得られる。またサーマルインクジェット方式のように熱を利用していないため、使用する溶液が熱劣化するということもなく、使用する溶液の制限が少ないというメリットがある。
【００８８】
一方でサーマルインクジェット方式の場合は、溶液の飛翔時に微小なサテライト滴を伴いながら飛翔するが、飛翔時の速度が速く（例えば１０ｍ／ｓ〜２０ｍ／ｓ）、安定した噴射飛翔が得られるというメリットがある。その結果、微小なサテライト滴も同様に高速（１０ｍ／ｓ〜２０ｍ／ｓ）で飛翔し、基板上の同一箇所に付着する。
【００８９】
つまり、サーマルインクジェット方式の場合は微小なサテライト滴が飛散しているように飛翔していても、発熱体への入力エネルギーをいつも一定にしてやれば、１ドットを形成するためのトータルの溶液量は同じ（同一箇所に付着するので）となり、同様に良好な丸いドットが得られる。
【００９０】
次に本発明のさらに他の特徴について説明する。本発明は、電子放出素子を製作する技術であるが、形成される電子放出素子部は、通常は基板上に先に形成されている一対の電極パターンの上に金属微粒子を分散させた溶液を噴射し、丸いドットパターンを形成し、電子放出素子を形成する。
ここで重要なことは、先に形成されているパターンの上に新たに金属微粒子を分散させた溶液を噴射し、そのパターンと先の電極パターンとの電気的接続を行う際の品質である。図７を使って説明する。
【００９１】
図７は、基板上に形成されている２つのＩＴＯ透明電極間に本発明の原理によって、金属微粒子を分散させた溶液を噴射し、丸いドットパターンを形成し、電子放出素子を形成する場合の模式的な図である。図中、Ｌｄは基板上にドットを単独で形成した場合のドット径である。
【００９２】
図７（Ａ）は、２つのＩＴＯ透明電極間に金属微粒子を分散させた溶液を噴射しドットパターンを形成した場合であるが、２つのＩＴＯ透明電極間は、ドットパターンの左右端部においてかろうじて電気的に接続されている例である。図７（Ｂ）は、図７（Ａ）の場合よりも、各ドットが周辺部で互いに重なり合って電気的に接続されている例であり、重なり領域の長さをＬｃで現している。図７（Ｃ）、（Ｄ）はさらに重なり合う領域Ｌｃが大である場合である。
【００９３】
ここで、単に電気的接続が得られるかどうかという観点から見ると、図７（Ａ）〜（Ｄ）の場合、すべて一応接続できている。しかしながら図７（Ａ）や図７（Ｂ）の場合、一応は接続されてはいるが、電気信号入力と同時に断線してしまう。あるいはすぐには断線しなくても接続部の接触抵抗が高すぎて異常発熱し、またそれが原因となって長期的信頼性がなく、いずれ断線にいたるという不具合があり、本来の性能を発揮できない。
【００９４】
本発明ではこれを解決するためにこのような接続領域において、基板上に先に形成されているパターンに対して、あとから金属微粒子を分散させた溶液を噴射しドットパターンを形成する際に、図７（Ｃ）、（Ｄ）のように端部のドットを１つのドットの半分以上、先に形成されているパターンの上に覆いかぶせるように打ち込み、形成するようにしている。
別の表現をするならば、ドットを単独で形成した場合のドット径をＬｄとする時、Ｌｄ／２≦ＬｃとなるようにＬｄとＬｃの関係が満たされるような、噴射口の大きさ（溶液噴射量）および打ち込み方法とする。
【００９５】
他の例で説明する。図８、図９の例は一対の電極と間の電子放出部が、図７のように一直線上に配列されているのではなく、電子放出部で直交するようなパターン配列の例としたが、必ずしもこのようなパターン配列に限定されるものではなく、図７のような構成であってもよいことはいうまでもない。
【００９６】
図８は、基板上に形成されている２つのＩＴＯ透明電極パターンである。このパターンは、スパッタリングならびにエッチングといういわゆるフォトリソグラフィー技術によって形成した。これに図９に示すように、Ａｇ微粒子含有溶液を約Φ１２μｍのドット径が得られるようにした噴射ヘッドを用い、その中心間距離（ドットピッチ）を約３μｍずつずらして重ね打ちし、ドットパターンを形成した。
この場合、ＩＴＯ透明電極パターンとの重なり領域の距離を約１３μｍ（Ｌｃｘ）と８μｍ（Ｌｃｙ）とし、１つのドット径の半分以上重ねて接続した。その結果、長期にわたり断線することなく安定したパターンが得られている。
【００９７】
図１０は他の例である。この場合は、先に形成されているパターンも、本発明の金属微粒子を分散させた溶液噴射によるドットパターンによって形成したものである。この場合も図１１に示したように、あとから形成するドットパターンの重なり領域（Ｌｃｘ，Ｌｃｙ）を、そのドットのドット径の半分以上重なるようにして接続した。
【００９８】
なおこの例は、先のドットパターンとあとのドットパターンが同じドット径となる例で示しているが、これらは必要に応じて異なるドット径のパターンにしてもよい。特に細い配線ラインではなく、デバイスの構成上大面積先のパターンを形成するような場合には、大きいノズル径を有する噴射ヘッドによって大きなドット径を得られるようにしたほうが効率的である。
またここで、２つの電極はＩＴＯ透明電極の例で実験、説明しているが、必ずしもＩＴＯに限定されるものではなく、Ａｌ，Ａｕ，Ｃｕ等の材料も好適に使用できる。
【００９９】
次に本発明のさらに別の特徴について図１２，図１３を用いて説明する。図１２は、先に示した図２（Ｂ）を拡大した図である。図１３は、本発明の特徴を説明するために、導電性薄膜４のパターンのそれぞれの領域を示したものである。本発明は、素子電極２，３の間に金属微粒子を分散させた溶液を噴射させ、ドットパターンとして形成しその後乾燥させることにより、導電性薄膜４を形成するものである。その際問題となるのは、先に形成されている素子電極２，３のパターンのエッジ部における導電性薄膜４のステップカバレッジである。
【０１００】
図１３（Ａ）に示したようにＡ部においては、先に形成されている素子電極のパターンの段差があるため、あとから金属微粒子を分散させた溶液を噴射させて、導電性薄膜４を形成した場合、エッジ部において良好な被覆が得られないという問題がある。そのため、その部位分において断線が生じたりして、電子放出素子の耐久性を損ね、信頼性が低く、実用面で難があった。
【０１０１】
本発明ではこの点に鑑み、この領域、すなわち基板上に先に形成されている素子電極のパターンエッジ部において、金属微粒子を分散させた溶液を噴射させて形成される導電性薄膜４の厚さをエッジ部ではない他の領域（図１３（Ｂ）のＢ部）より厚く形成するように噴射ヘッドを噴射制御するようにしている。
【０１０２】
具体的には、このＡの領域に溶液を噴射させる場合には、本発明に適用される噴射ヘッドにおいて、ピエゾ素子あるいは発熱体への入力エネルギーを大とし、Ｂの領域に噴射させる場合より、その液滴のサイズあるいは飛翔液体の質量を大きくすることによって、そこ（Ａの領域）に形成される膜厚を厚くすることができる。
【０１０３】
より具体的には、素子電極パターンの厚さを例えば３００Åとし、金属微粒子を分散させた溶液を噴射させて、導電性薄膜４を形成し、溶液中の揮発成分を乾燥させ、Ｂの領域における乾燥後の最終的な厚さを２００Åとなるようにした場合、Ａの領域の厚さは、３００Å〜５００Åとなるように噴射ヘッドを制御すれば、ステップカバレッジが良好で、長期使用しても断線等がなく、信頼性の高い電子放出素子とすることができる。
【０１０４】
以上の説明から明らかなように、本発明は、電子放出素子を製作する技術であるが、数１０μｍ〜数μｍという非常に微細なパターンを従来のようなフォトリソ技術によるのではなく、従来にはない微小な吐出口を有する噴射ヘッドによって金属微粒子を分散させた溶液を基板に直接噴射付与するという簡単な装置で、電子放出素子群をダイレクト製作するようにしている。したがって、いわゆる半導体製造プロセスで使用されている高価な製造装置を必要とせず、低コストでかつ安定して製作できるという利点がある。
【０１０５】
このようにして、良好な形状の表面伝導型電子放出素子群のパターン形成を行った後、本発明では以下に説明するようなフォーミング処理によって、電子放出部５を形成する（図１、図２参照）。
【０１０６】
電子放出部５は、導電性薄膜４の一部に形成された高抵抗の亀裂により構成され、導電性薄膜４の膜厚、膜質、材料等、あるいはフォーミング処理条件等に依存したものとなる。電子放出部５の内部には、１００Å以下の粒径の導電性微粒子を含む場合もある。
【０１０７】
この導電性薄膜４に施すフォーミング処理方法の一例として、通電処理による方法を説明する。素子電極２，３間に、不図示の電源を用いて通電を行うと、導電性薄膜４の部位に構造の変化した電子放出部５が形成される。すなわち、通電フォーミングによれば導電性薄膜４に局所的に破壊、変形もしくは変質等の構造変化した部位が形成され、この部位が電子放出部５となる。
【０１０８】
図１４は、本発明に適用する上記のごとくの通電フォーミング処理の電圧波形の例を示す図である。電圧波形は特にパルス波形が好ましく、パルス波高値が一定の電圧パルスを連続的に印加する場合（図１４（Ａ））と、パルス波高値を増加させながら、電圧パルスを印加する場合（図１４（Ｂ））とがある。まずパルス波高値が一定電圧とした場合（図１４（Ａ））について説明する。
【０１０９】
図１４（Ａ）におけるＴ１およびＴ２はそれぞれ電圧波形のパルス幅とパルス間隔であり、Ｔ１を１μｓ〜１０ｍｓ、Ｔ２を１０μｓ〜１００ｍｓとし、三角波の波高値（通電フォーミング時のピーク電圧）を表面伝導型電子放出素子の形態に応じて適宜選択する。このような条件のもと、例えば、数秒ないし数十分間電圧を印加する。また、パルス波形は三角波に限定されるものではなく、矩形波など所望の波形を用いても良い。
【０１１０】
図１４（Ｂ）におけるＴ１およびＴ２は、図１４（Ａ）に示したものと同様にそれぞれ電圧波形のパルス幅とパルス間隔を示し、三角波の波高値（通電フォーミング時のピーク電圧）は、例えば０．１Ｖステップ程度ずつ増加させることができる。
【０１１１】
通電フォーミング処理の終了は、パルス間隔Ｔ２中に、導電性薄膜４を局所的に破壊、変形しない程度の電圧を印加し、電流を測定して検知することができる。例えば０．１Ｖ程度の電圧印加により流れる素子電流を測定し、抵抗値を求めて、１ＭΩ以上の抵抗を示した時に通電フォーミングを終了させる。
【０１１２】
通電フォーミングを終了した素子には、活性化工程と呼ぶ処理を施すことが望ましい。活性化処理を施すことにより、素子電流Ｉｆ、放出電流Ｉｅが著しく変化する。活性化工程は、例えば有機物質のガスを含有する雰囲気下で、通電フォーミングと同様に、パルスの印加を繰り返すことで行うことができる。
【０１１３】
上記の雰囲気は、例えば油拡散ポンプやロータリーポンプなどを用いて真空容器内を廃棄した場合に雰囲気内に残留する有機ガスを利用して形成することができる他、イオンポンプなどにより一旦十分に排気した真空中に適当な有機物質のガスを導入することによっても得られる。このときの好ましい有機物質のガス圧は、前述の応用の形態、真空容器の形状や、有機物質の種類などにより異なるため場合に応じ適宜設定される。
【０１１４】
上記の有機物質としては、アルカン、アルケン、アルキンの脂肪族炭化水素類、芳香族炭化水素類、アルコール類、アルデヒド類、ケトン類、アミン類、フェノール、カルボン酸、スルホン酸等の有機酸類等を挙げることができ、具体的には、メタン、エタン、プロパンなどＣ_ｎＨ_２ｎ＋２で表される飽和炭化水素、エチレン、プロピレンなどＣ_ｎＨ_２ｎ等の組成式で表される不飽和炭化水素、ベンゼン、トルエン、メタノール、ホルムアルデヒド、アセトアルデヒド、アセトン、メチルエチルケトン、メチルアミン、エチルアミン、フェノール、蟻酸、酢酸、プロピオン酸等が使用できる。
【０１１５】
この処理により雰囲気中に存在する有機物質から炭素あるいは炭素化合物が素子上に堆積し、素子電流Ｉｆ、放出電流Ｉｅが著しく変化する。活性化工程の終了判定は、素子電流Ｉｆと放出電流Ｉｅを測定しながら行う。なおパルス幅、パルス間隔、パルス波高値などは適宜設定される。
【０１１６】
炭素あるいは炭素化合物とは、グラファイト（単結晶、多結晶の両者を指す）、非晶質カーボン（非晶質カーボンおよび非晶質カーボンと前記グラファイトの微結晶の混合物を含むカーボン）であり、その膜厚は５００Å以下にするのが好ましく、より好ましくは３００Å以下である。
【０１１７】
こうして作成した電子放出素子は、安定化処理を行うことが好ましい。この処理は真空容器内の有機物質の分圧が、１×１０^−８Ｔｏｒｒ以下、望ましくは１×１０^−１０Ｔｏｒｒ以下で行うのが良い。真空容器内の圧力は、１０^−６〜１０^−７Ｔｏｒｒ以下が好ましく、特に１×１０^−８Ｔｏｒｒ以下が好ましい。真空容器を排気する真空排気装置は、装置から発生するオイルが素子の特性に影響を与えないように、オイルを使用しないものを用いるのが好ましい。
【０１１８】
具体的には、ソープションポンプ、イオンポンプ等の真空排気装置を挙げることができる。さらに真空容器内を排気するときには、真空容器全体を過熱して真空容器内壁や電子放出素子に吸着した有機物質分子を排気しやすくするのが好ましい。このときの加熱した状態での真空排気条件は、８０〜２００℃で５時間以上が望ましいが、特にこの条件に限るものではなく、真空容器の大きさや形状、電子放出素子の構成などの諸条件により変化する。
【０１１９】
なお、上記有機物質の分圧は、質量分析装置により質量数が１０〜２００の炭素と水素を主成分とする有機分子の分圧を測定し、それらの分圧を積算することにより求められる。安定化工程を経た後、駆動時の雰囲気は、上記安定化処理終了時の雰囲気を維持するのが好ましいが、これに限るものではなく、有機物質が十分除去されていれば、真空度自体は多少低下しても十分安定な特性を維持することができる。このような真空雰囲気を採用することにより、新たな炭素あるいは炭素化合物の堆積を抑制でき、結果として素子電流Ｉｆ、放出電流Ｉｅが安定する。
【０１２０】
以上のようにして本発明の電子放出素子の作製ならびにフォーミングが行われ、その後、後述のように画像形成装置（ディスプレイ）として使用されるが、ここで１つ問題がある。これは上記のフォーミング処理時、またはディスプレイとして使用する場合も問題となることであるが、素子電極部における異常放電である。
【０１２１】
図１５を用いて説明する。本発明では、図１５のように複数（この例は２）個の対向する素子電極間に金属微粒子材料を含有する溶液のドットパターンによって電子放出部を形成してなるが、通常、素子電極は矩形パターンもしくは矩形パターンの組み合わせによって構成される。これは、このような素子電極パターンをフォトリソグラフィー技術によって形成する際のフォトマスクの形状に依存して、矩形形状にされる（矩形が最もコスト的に製作しやすい）わけであるが、図１５（Ａ）に示すように、対向する２個の素子電極のコーナー部が尖っているために、その部分で電界集中が生じる。
【０１２２】
その結果、フォーミング処理によって両電極間に印加したり、または最終的にディスプレイとして使用する場合も両電極間に印加するわけであるが、この電界集中部において異常な放電が生じ、良好なフォーミング処理が行えなかったり、または異常な電子放出がおきて、ディスプレイの画質を落とすという不具合がある。
【０１２３】
本発明ではこの点に鑑み、例えば図１５（Ｂ）のように複数の素子電極の互いに対向する側のコーナー部を面取り形状としている。この例は、機械図面で表示する際のｃ形状の面取りとしているが、ｒ形状の面取りであってもいいのは言うまでもない。
【０１２４】
このような形状は、素子電極パターンをフォトリソグラフィー技術によって形成する際にフォトマスクの形状をそのようなコーナー部が尖った形状にならないようにすればよい。あるいは、図１０で説明したように、素子電極を本発明の金属微粒子を分散させた溶液噴射によるドットパターンによって形成したものであれば、ドットパターンの外形そのものが丸い形状になっていて尖った部分がないので、自動的に面取り形状とすることができる。
【０１２５】
なお、その面取り部分の大きさは、電子放出部を形成するドットパターン径の１／２〜１／５程度、すなわちｃ２μｍ〜ｃ５μｍ、またはｒ２μｍ〜ｒ５μｍとすれば、電界集中が生じない良好な素子電極とすることができる。
【０１２６】
本発明では、このように素子電極の尖った部分をなくし、電界集中をなくすようにすることにより、フォーミング処理時、または後述のようにディスプレイとして使用する場合にも異常放電がなく、また長期に使用しても安定した良好な電子放出が得られ、さらには高品位な画質のディスプレイとすることができるようになった。
【０１２７】
次に本発明の画像形成装置について述べる。画像形成装置に用いる電子源基板の電子放出素子の配列については種々のものが採用できる。まず、並列に配置した多数の電子放出素子の個々を両端で接続し、電子放出素子の行を多数個配置し（行方向と呼ぶ）、この配線と直交する方向（列方向と呼ぶ）で電子放出素子の上方に配置した制御電極（グリッドとも呼ぶ）により、電子放出素子からの電子を制御駆動する梯子状配置のものがある。
【０１２８】
これとは別に、電子放出素子をＸ方向およびＹ方向に行列状に複数個配置し、同じ行に配置された複数の電子放出素子の電極の一方を、Ｘ方向の配線に共通に接続し、同じ列に配置された複数の電子放出素子の電極の他方を、Ｙ方向の配線に共通に接続するものが挙げられる。このようなものは、所謂、単純マトリックス配置である。まず単純マトリックス配置について以下に詳述する。
【０１２９】
図１６は、電子放出素子を複数個マトリックス状に配置して得られる電子源基板の一例を示す図で、図中、１０は電子源基板、１４は基板、６１はＸ方向配線、６２はＹ方向配線、６３は表面伝導型電子放出素子、６４は結線である。Ｘ方向配線６１は、ＤＸ１、ＤＸ２、・・・ＤＸｍのｍ本の配線からなり、Ｙ方向配線６２はＤＹ１、ＤＹ２、・・・ＤＹｎのｎ本の配線よりなる。また多数の表面伝導型素子６３にほぼ均等な電圧が供給されるように、材料、膜厚、配線幅が適宜設定される。これらｍ本のＸ方向配線６１とｎ本のＹ方向配線６２間は不図示の層間絶縁層により電気的に分離されてマトリックス配線を構成する（なお、上記ｍ、ｎは共に正の整数である）。
【０１３０】
不図示の層間絶縁層は、Ｘ方向配線６１を形成した基板１４の全面域または一部の所望の領域に形成される。Ｘ方向配線６１とＹ方向配線６２はそれぞれ外部端子として引き出される。更に表面伝導型放出素子６３の素子電極（不図示）がｍ本のＸ方向配線６１およびｎ本のＹ方向配線６２と結線６４によって電気的に接続されている。Ｘ方向配線６１とＹ方向配線６２を構成する材料、結線６４を構成する材料、及び一対の素子電極を構成する材料は、その構成元素の一部あるいは全部が同一であっても、またそれぞれ異なっても良い。
これらの材料は、例えば前述の素子電極の材料より適宜選択される。素子電極を構成する材料と配線材料が同一である場合には、素子電極に接続した配線も含めて素子電極ということもできる。
【０１３１】
Ｘ方向配線６１は、Ｘ方向に配列する表面伝導型放出素子６３の行を入力信号に応じて走査する走査信号を印加するための不図示の走査信号発生手段と電気的に接続されている。一方、Ｙ方向配線６２は、Ｙ方向に配列する表面伝導型放出素子６３の各列を入力信号に応じて変調する変調信号を印加するための不図示の変調信号発生手段と電気的に接続されている。
【０１３２】
更に表面伝導型電子放出素子６３の各素子に印加される駆動電圧は、当該素子に印加される走査信号と変調信号の差電圧として供給されるものである。これにより、単純なマトリックス配線だけで個別の素子を選択して独立に駆動可能になる。
【０１３３】
次に、以上のようにして作成した単純マトリックス配置の電子源を用いた画像形成装置について説明する。図１７は画像形成装置の表示パネルの基本構成の一例を説明するための図で、図中、１０は電子放出素子６３を基板上に作製した電子源基板、７１は電子源基板１０を固定したリアプレート、７２は支持枠、７６はガラス基板７３の内面に蛍光膜７４とメタルバック７５等が形成されたフェースプレートで、リアプレート７１、支持枠７２及びフェースプレート７６にフリットガラス等を塗布し、大気中あるいは窒素中で４００〜５００度で１０分以上焼成することで封着して外囲器７８を構成する。
【０１３４】
また、図１７において、６３は図１に示す構成に相当する電子放出素子、６１，６２はそれぞれ表面伝導型電子放出素子の一対の素子電極と接続されたＸ方向配線およびＹ方向配線である。
【０１３５】
外囲器７８は、上述の如くフェースプレート７６、支持枠７２、リアプレート７１で構成したが、リアプレート７１は主に電子源基板１０の強度を補強する目的で設けられるため、電子源基板１０自体で十分な強度を持つ場合は別体のリアプレート７１は不要であり、電子源基板１０に直接支持枠７２を封着し、フェースプレート７６、支持枠７２、及び電子源基板１０にて外囲器７８を構成しても良い。
またさらには、フェースプレート７６、リアプレート７１間に、スペーサとよばれる耐大気圧支持部材を設置することで大気圧に対して十分な強度をもつ外囲器７８を構成することもできる。
【０１３６】
いずれにしろ、このようなフェースプレートは、電子源基板と積層、一体化して画像形成装置（画像表示装置）を構成するので、電子源基板とほぼ同じ形状、大きさとされる。
【０１３７】
図１８は、図１７の画像形成装置に用いられる蛍光膜の構成例を示す模式図で、ブラックストライプタイプの蛍光膜を図１８（Ａ）に、ブラックマトリックスタイプの蛍光膜を図１８（Ｂ）に示すものである。図１８において、７４は蛍光膜、８１は黒色導電材、８２は蛍光体である。
【０１３８】
蛍光膜７４は、モノクロームの場合は蛍光体のみからなるが、カラーの蛍光膜の場合は、蛍光体の配列によりブラックストライプあるいはブラックマトリックスなどと呼ばれる黒色導電材８１と蛍光体８２とで構成される。ブラックストライプ、ブラックマトリックスを設ける目的は、カラー表示の場合、必要となる三原色蛍光体の各蛍光体８２間の塗り分け部を黒くすることで混色等を目立たなくすることと、蛍光膜７４における外光反射によるコントラストの低下を抑制することである。
【０１３９】
ブラックストライプの材料としては、通常良く用いられている黒鉛を主成分とする材料だけでなく、導電性があり、光の透過および反射が少ない材料であればこれに限るものではない。
【０１４０】
本発明では、上記のようなマトリックス化された蛍光体８２のストライプの方向、あるいはマトリックスの互いに直交する２方向と、前述の電子放出素子６３の互いに直交する２方向とそれぞれが互いに平行になるようにし、かつ各電子放出素子６３に蛍光体８２が一致するように位置決めして積層し、画像表示装置を構成している。
このような構成の画像表示装置は、互いのマトリックスの方向およびその位置が一致しているため、非常に高画質な画像表示装置を実現できる。
【０１４１】
ガラス基板７３に蛍光体を塗布する方法としては、モノクローム、カラーによらず沈澱法や印刷法が用いられる。また蛍光膜７４（図１８）の内面側には通常、メタルバック７５が設けられる。
【０１４２】
メタルバック７５は、蛍光体の発光のうち内面側への光をフェースプレート７６側へ鏡面反射することにより輝度を向上すること、電子ビーム加速電圧を印加するための電極として作用すること、外囲器内で発生した負イオンの衝突によるダメージからの蛍光体の保護等の役割を有する。メタルバック７５は、蛍光膜７４を作製後、蛍光膜７４の内面側表面の平滑化処理（通常、フィルミングと呼ばれる）を行い、その後Ａｌを真空蒸着等で堆積することで作製できる。また、フェースプレート７６には、更に蛍光膜７４の導電性を高めるため、蛍光膜７４の外面側に透明電極（不図示）を設けてもよい。
【０１４３】
前述の外囲器７８を作成するための封着を行う際、カラーの場合は各色蛍光体８２と電子放出素子６３とを対応させなくてはならず、十分な位置合わせを行う必要がある。この十分な位置合わせを行うために本発明では、前述のように、電子放出素子６３に対向する位置に蛍光体８２を配置するとともに、電子放出素子６３と蛍光体８２のそれぞれのマトリックスの互いに直交する２方向がそれぞれ互いに平行となるようにしている。
このような構成の高精度な画像表示装置を得るためには、蛍光体基板も、本発明の電子源基板と同様な位置決め手法をとることが望ましい。
【０１４４】
図１７に示した画像形成装置は、具体的には以下のようにして製造される。外囲器７８は前述の安定化工程と同様に、適宜加熱しながらイオンポンプ、ソープションポンプなどのオイルを使用しない排気装置により不図示の排気管を通じて排気し、１０^−７Ｔｏｒｒ程度の真空度の有機物質の十分少ない雰囲気にした後、封止される。
【０１４５】
外囲器７８の封止後の真空度を維持するためにゲッター処理を行う場合もある。これは外囲器７８の封止を行う直前あるいは封止後に抵抗加熱あるいは高周波加熱等の加熱法により、外囲器７８内の所定の位置（不図示）に配置されたゲッターを加熱し、蒸着膜を形成する処理である。ゲッターは通常Ｂａ等が主成分であり、蒸着膜の吸着作用により、例えば１×１０^−５Ｔｏｒｒないし１×１０^−７Ｔｏｒｒの真空度を維持するものである。
【０１４６】
次に、単純マトリックス配置型基板を有する電子源を用いて構成した表示パネルを駆動してＮＴＳＣ方式のテレビ信号に基づきテレビジョン表示を行うための駆動回路の一例を示す概略構成を説明する。図１９はＮＴＳＣ方式のテレビ信号に応じて表示を行うための駆動回路のブロック図で、その駆動回路を含む画像形成装置を表すものである。図１９において、９１は画像の表示パネル、９２は走査回路、９３は制御回路、９４はシフトレジスタ、９５はラインメモリ、９６は同期信号分離回路、９７は変調信号発生器、ＶｘおよびＶａは直流電圧源である。
【０１４７】
以下、図１９に示す各部の機能を説明する。表示パネル９１は端子Ｄｏｘ１ないしＤｏｘｍ、端子Ｄｏｙ１ないしＤｏｙｎ、及び高圧端子Ｈｖを介して外部の電気回路と接続している。このうち端子Ｄｏｘ１ないしＤｏｘｍには表示パネル９１内に設けられている電子源、すなわちＭ行Ｎ列の行列状にマトリックス配線された表面伝導型電子放出素子群を一行（Ｎ素子）ずつ順次駆動してゆくための走査信号が印加される。
【０１４８】
一方、端子Ｄｏｙ１ないしＤｏｙｎには前記の走査信号により選択された一行の表面伝導型電子放出素子の各素子の出力電子ビームを制御するための変調信号が印加される。また高圧端子Ｈｖには直流電圧源Ｖａより、例えば１０ｋＶの直流電圧が供給されるが、これは表面伝導型電子放出素子より出力される電子ビームに蛍光体を励起するのに十分なエネルギーを付与するための加速電圧である。
【０１４９】
次に走査回路９２について説明する。同回路は内部にＭ個のスイッチング素子を備えるもので（図中、Ｓ１ないしＳｍで模式的に示している）、各スイッチング素子は直流電圧源Ｖｘの出力電圧もしくは０Ｖ（グランドレベル）のいずれか一方を選択し、表示パネル９１の端子Ｄｏｘ１ないしＤｏｘｍと電気的に接続するものである。
【０１５０】
Ｓ１ないしＳｍの各スイッチング素子は制御回路９３が出力する制御信号Ｔｓｃａｎに基づいて動作するものであるが、実際には例えばＦＥＴのようなスイッチング素子を組み合わせることにより構成することが可能である。なお、前記直流電圧源Ｖｘは、前記表面伝導型電子放出素子の特性（電子放出しきい値電圧）に基づき、走査されていない素子に印加される駆動電圧が電子放出しきい値電圧以下となるような一定電圧を出力するよう設定されている。
【０１５１】
制御回路９３は、外部より入力する画像信号に基づいて適切な表示が行われるように各部の動作を整合させる働きをもつものである。この後説明する同期信号分離回路９６より送られる同期信号Ｔｓｙｎｃに基づいて、各部に対してＴｓｃａｎ、Ｔｓｆｔ及びＴｍｒｙの各制御信号を発生する。
【０１５２】
同期信号分離回路９６は、外部から入力されるＮＴＳＣ方式のテレビ信号から同期信号成分と輝度信号成分とを分離するための回路であり、周波数分離（フィルタ）回路を用いれば構成できる。同期信号分離回路９６により分離された同期信号は、良く知られるように垂直同期信号と水平同期信号よりなるが、ここでは説明の便宜上Ｔｓｙｎｃ信号として図示した。一方、前記テレビ信号から分離された画像の輝度信号成分を便宜上ＤＡＴＡ信号と表すが、同信号はシフトレジスタ９４に入力される。
【０１５３】
シフトレジスタ９４は、時系列的にシリアルに入力される前記ＤＡＴＡ信号を画像の１ライン毎にシリアル／パラレル変換するためのものであり、制御回路９３より送られる制御信号Ｔｓｆｔに基づいて動作する。すなわち制御信号Ｔｓｆｔは、シフトレジスタ９４のシフトクロックであると言い換えても良い。シリアル／パラレル変換された画像１ライン分（電子放出素子Ｎ素子分の駆動データに相当する）のデータはＩｄ１ないしＩｄｎのＮ個の並列信号としてシフトレジスタ９４より出力される。
【０１５４】
ラインメモリ９５は、画像１ライン分のデータを必要時間の間だけ記憶するための記憶装置であり、制御回路９３より送られる制御信号Ｔｍｒｙに従って適宜Ｉｄ１ないしＩｄｎの内容を記憶する。記憶した内容は、Ｉｄ′１ないしＩｄ′ｎとして出力され変調信号発生器９７に入力する。
【０１５５】
変調信号発生器９７は、前記画像データＩｄ′１ないしＩｄ′ｎの各々に応じて表面伝導型電子放出素子の各々を適切に駆動変調するための信号源であり、その出力信号は端子Ｄｏｙ１ないしＤｏｙｎを通じて表示パネル９１内の表面伝導型電子放出素子に印加される。
【０１５６】
前述したように本発明に関わる電子放出素子は、放出電流Ｉｅに対して以下の基本特性を有している。すなわち前述したように電子放出には明確なしきい値電圧Ｖｔｈがあり、Ｖｔｈ以上の電圧を印加された時のみ電子放出が生じる。また電子放出しきい値以上の電圧に対しては素子への印加電圧の変化に応じて放出電流も変化していく。なお、電子放出素子の材料や構成、製造方法を変えることにより電子放出しきい値電圧Ｖｔｈの値や印加電圧に対する放出電流の変化の度合いが変わる場合もあるが、いずれにしても以下のようなことがいえる。
【０１５７】
すなわち、本素子にパルス状の電圧を印加する場合、例えば電子放出しきい値以下の電圧を印加しても電子放出は生じないが、電子放出しきい値以上の電圧を印加する場合には電子ビームが出力される。その際、第一にはパルスの波高値Ｖｍを変化させることにより出力電子ビームの強度を制御することが可能であり、第二には、パルスの幅Ｐｗを変化させることにより出力される電子ビームの電荷の総量を制御することが可能である。
【０１５８】
従って、入力信号に応じて電子放出素子を変調する方式としては、電圧変調方式、パルス幅変調方式等があげられ、電圧変調方式を実施するには、変調信号発生器９７として、一定の長さの電圧パルスを発生するが、入力されるデータに応じて適宜パルスの波高値を変調するような電圧変調方式の回路を用いる。またパルス幅変調方式を実施するには、変調信号発生器９７としては、一定の波高値の電圧パルスを発生するが、入力されるデータに応じて適宜電圧パルスの幅を変調するようなパルス幅変調方式の回路を用いる。
【０１５９】
シフトレジスタ９４やラインメモリ９５は、デジタル信号式のものであってもアナログ信号式のものであっても差し支えなく、画像信号のシリアル／パラレル変換や記憶が所定の速度で行われればよい。
【０１６０】
デジタル信号式のものを用いる場合には、同期信号分離回路９６の出力信号ＤＡＴＡをデジタル信号化する必要があるが、これは同期信号分離回路９６の出力部にＡ／Ｄ変換器を備えれば可能である。また、これと関連してラインメモリ９５の出力信号がデジタル信号かアナログ信号かにより、変調信号発生器９７に用いられる回路が若干異なったものとなる。
【０１６１】
まずデジタル信号の場合について述べる。電圧変調方式において、変調信号発生器９７には、例えばよく知られるＤ／Ａ変換回路を用い、必要に応じて増幅回路などを付け加えればよい。またパルス幅変調方式の場合、変調信号発生器９７は、例えば高速の発振器、発振器が出力する波数を計数する計数器（カウンタ）、及び計数器の出力値とラインメモリ９５の出力値を比較する比較器（コンパレータ）を組み合せた回路を用いることにより構成できる。必要に応じて比較器の出力するパルス幅変調された変調信号を表面伝導型電子放出素子の駆動電圧にまで電圧増幅するための増幅器を付け加えてもよい。
【０１６２】
次にアナログ信号の場合について述べる。電圧変調方式においては変調信号発生器９７には、例えばよく知られるオペアンプなどを用いた増幅回路を用いればよく、必要に応じてレベルシフト回路などを付け加えてもよい。またパルス幅変調方式の場合には例えばよく知られた電圧制御型発振回路（ＶＣＯ）を用いればよく、必要に応じて表面伝導型電子放出素子の駆動電圧にまで電圧増幅するための増幅器を付け加えてもよい。
【０１６３】
以上のような構成を有する画像表示装置において、表示パネル９１の各電子放出素子には、容器外端子Ｄｏｘ１ないしＤｏｘｍ、Ｄｏｙ１ないしＤｏｙｎを通じ、電圧を印加することにより、電子放出させるとともに、高圧端子Ｈｖを通じ、メタルバック７５あるいは透明電極（不図示）に高圧を印加して電子ビームを加速し、蛍光膜７４に衝突させ、励起・発光させることで画像を表示することができる。
【０１６４】
ここで述べた構成は、表示等に用いられる好適な画像形成装置を作製する上で必要な概略構成であり、例えば各部材の材料等、詳細な部分は上述内容に限られるものではなく、画像形成装置の用途に適するよう適宜選択する。また、入力信号例として、ＮＴＳＣ方式をあげたが、これに限るものでなく、ＰＡＬ、ＳＥＣＡＭ方式などの諸方式でもよく、また、これよりも、多数の走査線からなるＴＶ信号（例えば、ＭＵＳＥ方式をはじめとする高品位ＴＶ）方式でもよい。
【０１６５】
次に、梯子型配置電子源基板および画像表示装置について説明する。図２０は、電子放出素子を梯子型に配置した電子源基板の構成例を示す模式図で、図中、１００は電子源基板、１４は基板、６３は電子放出素子、９８は電子放出素子６３に接続したＤｘ１〜Ｄｘ１０よりなる共通配線である。電子放出素子６３は、基板１４上にＸ方向に並列に複数個配置されている（この配列を素子行と呼ぶ）。
【０１６６】
この素子行が複数個基板上に配置され、電子源基板１００が構成されている。各素子行の共通配線間に駆動電圧を印加することで、各素子行を独立に駆動させることができる。すなわち、電子ビームを放出させたい素子行には、電子放出しきい値以上の電圧を印加し、電子ビームを放出させない素子行には電子放出しきい値以下の電圧を印加すればよい。また、各素子行間の共通配線Ｄｘ２〜Ｄｘ９、例えばＤｘ２、Ｄｘ３を同一配線とするようにしても良い。
【０１６７】
図２１は、図２０に示すごとくの梯子型配置電子源基板を備えた画像表示装置におけるパネル構造を説明するための図で、図中、１００は各素子行間の共通配線を同一配線とした電子源基板、１０１はグリッド電極、１０２は電子が通過するための開口、１０３はＤｏｘ１、Ｄｏｘ２・・・Ｄｏｘｍよりなる容器外端子、１０４はグリッド電極１０１と接続されたＧ１、Ｇ２、・・・Ｇｎからなる容器外端子で、その他、図１６または図１８と同様の機能を有する部分には、同一符号を付してある。
【０１６８】
図２１に示す画像表示装置における前述の単純マトリックス配置の画像表示装置（図１７）との違いは、電子源基板１００とフェースプレート７６の間にグリッド電極１０１を備えていることである。グリッド電極１０１は、表面伝導型放出素子から放出された電子ビームを変調するためのものであり、梯子型配置の素子行と直交して設けられたストライプ状の電極に電子ビームを通過させるため、各素子に対応して１個ずつ円形の開口１０２が設けられている。
【０１６９】
なおグリッドの形状や設置位置は図２０に示したものに限定されるものではない。例えば、開口としてメッシュ状に多数の通過口を設けることもでき、グリッドを表面伝導型放出素子の周囲や近傍に設けることもできる。また、容器外端子１０３及びグリッド容器外端子１０４は、不図示の制御回路と電気的に接続されている。
【０１７０】
本画像形成装置では、素子行を１列ずつ順次駆動（走査）していくのと同期してグリッド電極列に画像１ライン分の変調信号を同時に印加する。これにより、各電子ビームの蛍光体への照射を制御し、画像を１ラインずつ表示することができる。これによればテレビジョン放送の表示装置、テレビ会議システム、コンピュータ等の表示装置の他、感光性ドラム等で用いて構成された光プリンターとしての画像形成装置としても用いることもできる。
【０１７１】
【発明の効果】
以上、詳述したように、請求項１に記載の発明によれば、基板上の複数の各素子電極間に導電性薄膜を形成するための金属微粒子材料を含有する溶液を噴射ヘッドにより噴射付与し、前記導電性薄膜による表面伝導型電子放出素子群を形成する電子源基板製造装置において、前記表面伝導型電子放出素子の電子放出部が前記溶液のドットパターンによって形成され、前記素子電極が矩形パターンまたは矩形パターンの組み合わせによって構成されるとともに、前記矩形パターンのコーナー部を面取り形状としたので、異常放電の起きない高品質かつ信頼性の高い電子放出素子を有する電子源基板を製造できる電子源基板製造装置を提供することができる。
【０１７２】
請求項２に記載の発明によれば、基板上の複数の各素子電極間に導電性薄膜を形成するための金属微粒子材料を含有する溶液を噴射ヘッドにより噴射付与し、導電性薄膜による表面伝導型電子放出素子群を形成する電子源基板製造装置によって製作される電子源基板において、前記導電性薄膜が前記溶液付与後に溶媒成分を揮発させてなる前記溶液のドットパターンによって形成される薄膜であり、
前記素子電極が矩形パターンまたは矩形パターンの組み合わせによって構成されるとともに、前記矩形パターンのコーナー部を面取り形状としたので、異常放電の起きない高品質かつ信頼性の高い電子放出素子を有する電子源基板を得ることができる。
【０１７３】
請求項３に記載の発明によれば、前記複数の素子電極の互いに対向する側のコーナー部を面取り形状としたので、異常放電の起きない高品質かつ信頼性の高い電子放出素子を有する電子源基板が得られる。
【０１７４】
請求項４に記載の発明によれば、請求項２または３に記載の電子源基板と、該電子源基板に対向して配置され、蛍光体を搭載し、前記電子源基板とほぼ同じ形状、大きさのフェースプレートとを有するので、異常放電の起きない高品質かつ信頼性の高い電子放出素子を有する電子源基板を使用することにより，高画質で耐久性の高い画像表示装置を提供することができる。
【図面の簡単な説明】
【図１】本発明の一実施形態に係る平面型表面伝導型電子放出素子の構成を示す模式図であり、（Ａ）は平面図、（Ｂ）は（Ａ）のＢ−Ｂ線断面図である。
【図２】図１に示す表面伝導型電子放出素子の製造方法を説明するための模式図であり、（Ａ）は基板に素子電極を形成した図、（Ｂ）は素子電極に導電性薄膜を形成した図、（Ｃ）は導電性薄膜に電子放出部を形成した図である。
【図３】本発明に係る電子源基板の製造装置の一例を示す構成図である。
【図４】本発明を適用し得る液滴付与装置の構成の一例を説明するための図である。
【図５】（Ａ）および（Ｂ）は、図４の液滴付与装置の吐出ヘッドユニットの要部概略構成図である。
【図６】（Ａ）〜（Ｃ）は、本発明に係る表面伝導型電子放出素子の製造装置に使用される噴射ヘッドの１例を示す図である。
【図７】（Ａ）〜（Ｄ）は、液滴のドットを配列して電子放出素子パターンを形成する場合の接続方法を説明するための図である。
【図８】基板上に形成されている２つのＩＴＯ透明電極パターンを説明するための図である。
【図９】液滴のドットを配列して電子放出素子パターンを形成する具体例を説明するための図である。
【図１０】基板上に先に形成したドットパターンを示す図である。
【図１１】基板上に先に形成したドットパターンに液滴のドットを配列して電子放出素子パターンを形成する具体例を説明するための図である。
【図１２】本発明の一実施形態に係る平面型表面伝導型電子放出素子の構成を断面図で示したものである。
【図１３】（Ａ）および（Ｂ）は、電子放出部および電極素子部における電子放出素子パターンの膜厚を変える事を説明するための断面図である。
【図１４】（Ａ）および（Ｂ）は、本発明による表面伝導型電子放出素子の製造に採用できる通電フォーミング処理における電圧波形の例を示す図である。
【図１５】（Ａ）は従来の素子電極の尖っているコーナー部で電界集中が生じる例を説明するための図であり、（Ｂ）は本発明を適用し電界集中をなくした例を説明するための図である。
【図１６】本発明を適用し得るマトリックス配置型電子源基板の一例を示す模式図である。
【図１７】本発明を適用し得るマトリックス配置型電子源基板による画像形成装置の表示パネルの基本構成の一例を説明するための図である。
【図１８】本発明を適用し得る画像形成装置に用いられる蛍光膜の構成例を示す模式図であり、（Ａ）は、ブラックストライプタイプの蛍光膜、（Ｂ）は、ブラックマトリックスタイプの蛍光膜である。
【図１９】画像形成装置にＮＴＳＣ方式のテレビ信号に応じて表示を行うための駆動回路の一例を示すブロック図である。
【図２０】本発明を適用し得る梯子型配置型電子源基板の一例を示す模式図である。
【図２１】本発明を適用し得る梯子型配置型電子源基板による画像形成装置の表示パネル基本構成の一例を説明するための図である。
【図２２】従来の電子放出素子の一例を示す図である。
【符号の説明】
１ 基板
２，３ 素子電極
４ 導電性薄膜
５ 電子放出部
１０ 電子源基板
１１ 吐出ヘッドユニット（噴射ヘッド）
１２ キャリッジ
１３ 基板保持台
１４ 基板
１５ 供給チューブ
１６ 信号供給ケーブル
１７ 噴射ヘッドコントロールボックス
１８ キャリッジ１２のＸ方向スキャンモータ
１９ キャリッジ１２のＹ方向スキャンモータ
２０ コンピュータ
２１ コントロールボックス
２２Ｘ１、２２Ｙ１、２２Ｘ２、２２Ｙ２ 基板位置決め／保持手段
３０ 吐出ヘッドユニット
３１ ヘッドアライメント制御機構
３２ 検出光学系
３３ インクジェットヘッド
３４ ヘッドアライメント微動機構
３５ 制御コンピュータ
３６ 画像識別機構
３７ ＸＹ方向走査機構
３８ 位置検出機構
３９ 位置補正制御機構
４０ インクジェットヘッド駆動・制御機構
４１ 光軸
４２ 液滴
４３ 液滴着弾位置
４４ ドット
５０ 噴射ヘッド（インクジェットヘッド）
５１ 発熱体基板
５２ 蓋基板
５３ 発熱体基板５１の作成に用いるシリコン基板
５４ 個別電極
５５ 共通電極
５６ 発熱体
５７ 溶液流入口
５８ ノズル
５９ 溝部
６０ 凹部領域
６１ Ｘ方向配線
６２ Ｙ方向配線
６３ 表面伝導型電子放出素子
６４ 結線
７１ 電子源基板１０を固定したリアプレート
７２ 支持枠
７３ ガラス基板
７４ 蛍光膜
７５ メタルバック
７６ フェースプレート
７８ 外囲器
８１ 黒色導電材
８２ 蛍光体
９１ 画像の表示パネル
９２ 走査回路
９３ 制御回路
９４ シフトレジスタ
９５ ラインメモリ
９６ 同期信号分離回路
９７ 変調信号発生器
９８ 電子放出素子６３に接続したＤｘ１〜Ｄｘ１０よりなる共通配線
１００ 各素子行間の共通配線を同一配線とした電子源基板
１０１ グリッド電極
１０２ 電子が通過するための開口
１０３ Ｄｏｘ１，Ｄｏｘ２・・・Ｄｏｘｍよりなる容器外端子
１０４ グリッド電極１０１と接続されたＧ１，Ｇ２・・・Ｇｎからなる容器外端子
Ｖｘ，Ｖａ 直流電圧源[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electron source substrate using a surface conduction electron-emitting device, an electron source substrate manufacturing apparatus for manufacturing the electron source substrate, and an image display device using the electron source substrate.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, two types of electron emitting devices, a thermionic electron source and a cold cathode electron source, are known. The cold cathode electron source includes a field emission type (hereinafter, referred to as “FE type”), a metal / insulating layer / metal type (hereinafter, referred to as “MIM type”), a surface conduction type electron emission element, and the like.
Examples of the FE type include “WP Dyke & WW Dolan,“ Fielddemion ”, Advance in Electron Physics, 889 (1956)”, or “CA Spindet,“ Physical properties in a first-order dimension. With molebdenium, “J. Appl. Phys., 475248 (1976)” and the like are known.
[0003]
As examples of the MIM type, “CA Mead,“ The Tunnel-emission amplifier ”, J. Appl. Phys., 32 646 (1961)” and the like are known.
[0004]
Examples of the surface conduction electron-emitting device include “MI Elinson, Radio Eng. Electron Phys., 1290 (1965)” and the like. The surface conduction electron-emitting device utilizes a phenomenon in which an electron is emitted when a current flows through a small-area thin film formed on a substrate in parallel with the film surface.
As the surface conduction electron-emitting device, SnO by Elinson et al. ₂ A film using a thin film, a film using an Au thin film (“G. Dittmer:“ Thin Solid Films ”, 9317 (1972))”, In ₂ O ₃ / SnO ₂ By a thin film ("M. Hartwell and CG Fonstad:" IEEE Trans. ED Conf. ", 519 (1975))", and by a carbon thin film ("Hisashi Araki et al .: Vacuum, Vol. 26, No. 1, 22 (1983) ").
[0005]
A typical device configuration of these surface conduction electron-emitting devices is described in the aforementioned M.A. The Hartwell device configuration is shown in FIG. In FIG. 22, a is a substrate, b and c are device electrodes, d is a conductive thin film, and the conductive thin film d is a metal oxide thin film or the like formed by sputtering in an H-shaped pattern. The electron emission portion e is formed by an energization process called energization forming. The distance L1 between the device electrodes b and c in the figure is set to 0.5 to 1 mm, and W1 is set to 0.1 mm.
[0006]
Conventionally, in these surface conduction electron-emitting devices, an electron-emitting portion e is generally formed by subjecting a conductive thin film d to an energization process called energization forming before performing electron emission. . The energization forming is to apply a direct current voltage or a very slowly increasing voltage, for example, about 1 V / min, to both ends of the conductive thin film d and to energize the conductive thin film d, thereby locally destroying, deforming or altering the conductive thin film d. The purpose is to form the electron emitting portion e in a high resistance state.
[0007]
In the electron emitting portion e, a crack is generated in a part of the conductive thin film d, and electrons are emitted from the vicinity of the crack. In the surface conduction type electron-emitting device subjected to the energization forming process, a voltage is applied to the conductive thin film d, and a current is caused to flow through the device to cause the electron-emitting portion e to emit electrons.
[0008]
The surface conduction electron-emitting device as described above has an advantage that a large number of devices can be arranged and formed over a large area because the structure is simple and the production is easy. Therefore, applied research on charged beam sources, display devices, and the like utilizing this feature has been made.
[0009]
As an example in which a large number of surface conduction electron-emitting devices are arranged and arranged, as will be described later, surface conduction electron-emitting devices are arranged in parallel called a trapezoidal arrangement, and both ends of each element are interconnected (also called a common interconnect). ), An electron source in which a plurality of connected lines are arranged (for example, JP-A-64-31332, JP-A-1-283737, JP-A-2-257552, etc.).
[0010]
In addition, in particular, in image forming apparatuses such as display apparatuses, flat panel display apparatuses using liquid crystal have become widespread in place of CRTs in recent years. However, they are not self-luminous and must have a backlight. Therefore, development of a self-luminous display device has been desired. An example of the self-luminous display device is an image forming device, which is a display device in which an electron source having a large number of surface conduction emission elements arranged therein and a phosphor that emits visible light by electrons emitted from the electron source are combined. (For example, US Pat. No. 5,066,883).
[0011]
However, the method of manufacturing a surface conduction electron-emitting device according to the above-described conventional example uses a lot of photolithography and etching methods in vacuum film formation and a semiconductor process. However, there is a disadvantage that the production cost of the electron source substrate is high.
[0012]
In order to solve the problems described above, the present inventor disclosed in US Pat. Nos. 3,060,429, 3,298,030, 3,596,275 and No. 3,416,153, No. 3,747,120, No. 5,729,257, etc., the above-mentioned conductive material can be stably produced at a good yield and at low cost without using a vacuum film forming method and a photolithographic etching method. It was thought that a conductive thin film could be formed. And the result of having examined variously about the concrete production method is disclosed (for example, patent document 1).
[0013]
[Patent Document 1]
JP 2001-319567 A
[0014]
However, unlike ink-jet recording, in which the so-called ink is directed toward paper and recorded, there are many unsolved elements to stably fly a solution containing an element that becomes a conductive thin film and apply it on a substrate. Exists. For example, such an element is generally a metal element, and there are still many unknown techniques for stably spraying a solution containing fine metal particles over a long period of time. In particular, in order to keep the injection performance over a long period of time, the problem of clogging must be solved.
[0015]
Conventionally, in the field of ink jet recording using a recording liquid in which a water-soluble dye is dissolved, the discharge port (nozzle) of a head used is conventionally Φ33 μm to Φ34 μm (cross-sectional area 900 μm). ² ), Φ50 μm to Φ51 μm (cross-sectional area 2000 μm ² ) Is common and the dye is also dissolved in the liquid medium, so that the problem of clogging has been addressed. However, the solution containing metal fine particles as in the present invention is, for example, Φ25 μm or less (cross-sectional area 500 μm ² ), A technique for stably ejecting from an unprecedented fine discharge port for a long time has not been established.
[0016]
[Problems to be solved by the invention]
The present invention relates to an electron source substrate of an image display device using a surface conduction electron-emitting device as described above and an image display device using the same. The object of the invention of claim 1 is to provide high quality and high reliability. It is an object of the present invention to provide an electron source substrate manufacturing apparatus capable of manufacturing an electron source substrate having an electron-emitting device having a high density.
[0017]
It is an object of the present invention to provide an electron source substrate having a high-quality and highly reliable electron-emitting device. The object of the third invention is the same as that of the second invention. Another object of the present invention is to provide a high-quality image display device using an electron source substrate having a high-quality and highly reliable electron-emitting device.
[0018]
[Means for Solving the Problems]
According to the first aspect of the present invention, a solution containing a metal fine particle material for forming a conductive thin film between a plurality of device electrodes on a substrate is sprayed and applied by a spray head, and the surface conductive electron emission by the conductive thin film is performed. In an electron source substrate manufacturing apparatus for forming an element group,
An electron emission portion of the surface conduction electron-emitting device is formed by a dot pattern of the solution,
The device electrode is configured by a rectangular pattern or a combination of rectangular patterns, and a corner of the rectangular pattern is chamfered.
[0019]
According to a second aspect of the present invention, a solution containing a metal particulate material for forming a conductive thin film between a plurality of device electrodes on a substrate is sprayed by a spray head, and a surface conduction electron-emitting device using the conductive thin film is provided. In an electron source substrate manufactured by an electron source substrate manufacturing apparatus forming a group,
The conductive thin film is a thin film formed by a dot pattern of the solution obtained by volatilizing a solvent component after applying the solution,
The device electrode is configured by a rectangular pattern or a combination of rectangular patterns, and a corner of the rectangular pattern is chamfered.
[0020]
According to a third aspect of the present invention, in the electron source substrate according to the second aspect, the corners of the plurality of element electrodes facing each other are chamfered.
[0021]
According to a fourth aspect of the present invention, there is provided an image display device, wherein the electron source substrate according to the second or third aspect is disposed so as to face the electron source substrate, a phosphor is mounted, and the electron source substrate has substantially the same shape as the electron source substrate. , And a face plate of a size.
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a schematic view showing an example of an electron source substrate constituting a planar surface conduction electron-emitting device according to an embodiment of the present invention. FIG. 1 (A) is a plan view thereof, and FIG. FIG. 1A is a cross-sectional view taken along the line BB of FIG. 1A, wherein 1 is a substrate, 2 and 3 are device electrodes, 4 is a conductive thin film, and 5 is an electron emitting portion.
[0023]
The basic configuration of the surface conduction electron-emitting device of the present invention is a plane type, and here, for simplification, the configuration of one flat surface conduction electron-emitting device is schematically shown. As described later, such a planar surface conduction electron-emitting device is configured as a device group in which the devices are arranged in a matrix.
[0024]
Examples of the substrate 1 include quartz glass, glass with a reduced content of impurities such as Na, blue plate glass, and SiO 2. ₂ And a ceramic substrate made of alumina or the like, on the surface of which is deposited.
[0025]
As a material for the device electrodes 2 and 3, a general conductive material can be used. For example, metals or alloys such as Ni, Cr, Au, Mo, W, Pt, Ti, Al, Cu, and Pd, Pd, As, Ag, Au, RuO ₂ , A printed conductor composed of a metal such as Pd-Ag or a metal oxide and glass, In, ₂ O ₃ -SnO ₂ And the like, and a semiconductor material such as polysilicon and the like.
[0026]
The distance L between the device electrodes 2 and 3 is preferably in the range of several thousand to several hundred μm, and more preferably in the range of 1 to 100 μm in consideration of the voltage applied between the device electrodes 2 and 3. . The length W of the device electrodes 2 and 3 is several μm to several hundred μm in consideration of the resistance value and the electron emission characteristics of the electrodes, and the film thickness d of the device electrodes 2 and 3 is 100 ° to 1 μm. Range. The present invention is not limited to the configuration shown in FIG. 1, but may be a configuration in which the conductive thin film 4 and the electrodes of the device electrodes 2 and 3 are sequentially formed on the substrate 1.
[0027]
2A and 2B are views for explaining a method of manufacturing the flat surface conduction electron-emitting device shown in FIG. 1. FIG. 2A is a diagram in which device electrodes 2 and 3 are formed on a substrate 1, and FIG. 2B is a diagram in which the conductive thin film 4 is formed on the device electrodes 2 and 3, and FIG. 2C is a diagram in which the electron emission portion 5 is formed on the conductive thin film 4.
[0028]
As the conductive thin film 4, a fine particle film composed of fine particles is particularly preferable in order to obtain good electron emission characteristics, and the thickness thereof is step coverage to the device electrodes 2 and 3, and the resistance between the device electrodes 2 and 3 is small. It is appropriately set depending on the value and the energizing forming conditions described later, but is preferably several to several thousand degrees, particularly preferably 10 to 500 degrees. Further, the resistance value is a value of Rs of 10 2 to 10 7 Ω. Here, Rs is a value that appears when the resistance R of a thin film having a thickness t, a width w, and a length of 1 is set as R = Rs (1 / w), and the resistivity of the thin film material is ρ. It is expressed by Rs = ρ / t.
[0029]
Here, the forming process will be described by taking an energizing process as an example, but the forming process is not limited to this, and any method may be used as long as it forms a high resistance state by causing a crack in the film. May be.
[0030]
As a material constituting the conductive thin film 4, metals such as Pd, Pt, Ru, Ag, Zn, Sn, W, and Pb can emit good electrons as the surface conduction electron-emitting device of the present invention. As a material. However, as will be described later, it is necessary to consider compatibility with the droplet ejection head used in the manufacturing apparatus of the present invention, and not all of these materials can be used suitably.
[0031]
The fine particle film described here is a film in which a plurality of fine particles are aggregated, and has a fine structure not only in a state in which the fine particles are individually dispersed and arranged, but also in a state in which the fine particles are adjacent to each other or overlap each other (some fine particles are aggregated). (Including the case where an island shape is formed as a whole). The particle size of the fine particles is from several millimeters to 1 micrometer, preferably from 10 millimeters to 200 millimeters.
[0032]
Hereinafter, an apparatus for manufacturing an electron source substrate on which a surface conduction electron-emitting device according to an embodiment of the present invention is formed will be described. FIG. 3 is a view showing an example of an apparatus for manufacturing an electron source substrate according to the present invention. In the figure, 11 is an ejection head unit (ejection head), 12 is a carriage, 13 is a substrate holder, and 14 is a planar surface conduction. A substrate forming a group of electron-emitting devices, 15 is a supply tube for a solution containing a conductive thin film material, 16 is a signal supply cable, 17 is an ejection head control box, 18 is an X-direction scan motor of the carriage 12, and 19 is The Y-direction scan motor of the carriage 12, 20 is a computer, 21 is a control box, and 22X1, 22Y1, 22X2, and 22Y2 are substrate positioning / holding means.
[0033]
The configuration shown in FIG. 3 shows an example in which the ejection head 11 is moved by carriage scanning on the front surface of the substrate 14 placed on the substrate holding table 13 and ejects a solution containing a conductive thin film material. The ejection head 11 may be any mechanism as long as it can discharge a given amount of liquid droplets, and particularly preferably an ink jet type mechanism capable of forming droplets of about several tens to several picoliters, or droplets of a smaller volume. . As the inkjet method, any of a piezo jet method using a piezoelectric element, a bubble jet (registered trademark) method in which bubbles are generated using thermal energy of a heater, and a charge control method (continuous flow method) may be used. .
[0034]
FIG. 4 is a schematic view for explaining an example of the configuration of a droplet applying apparatus to which the method of manufacturing an electron source substrate according to the present invention can be applied. FIG. FIG. 3 is a schematic configuration diagram of main parts. The configuration of FIG. 4 differs from the configuration of FIG. 3 in that the electron-emitting device group is formed on the substrate by moving the substrate side.
[0035]
4 and 5, reference numerals 2 and 3 denote element electrodes, 14 denotes a substrate, 30 denotes a discharge head unit (corresponding to the discharge head 11 in FIG. 3), 31 denotes a head alignment control mechanism, 32 denotes a detection optical system, and 33 denotes an ink jet. A head, 34 is a head alignment fine movement mechanism, 35 is a control computer, 36 is an image identification mechanism, 37 is an XY scanning mechanism, 38 is a position detection mechanism, 39 is a position correction control mechanism, 40 is an inkjet head drive / control mechanism, 41 Is an optical axis, 42 is a droplet, and 43 is a droplet landing position.
[0036]
As the droplet applying device (ink jet head 33) of the ejection head unit 30, an ink jet type mechanism is desirable, as in the case of FIG. 3, and a piezo jet type using a piezoelectric element, bubbles using a thermal energy of a heater are used. May be used, such as a bubble jet (registered trademark) method or a charge control method (continuous flow method).
[0037]
Hereinafter, the configuration of the apparatus for moving the substrate 14 as described above will be described. First, in FIG. 4, the substrate 14 is placed on the XY scanning mechanism 37. The surface conduction electron-emitting device on the substrate 14 has the same configuration as that of FIG. 1. As a single device, the substrate 1, the device electrodes 2, 3 and the conductive thin film (fine particle film) are similar to those shown in FIG. It consists of four.
[0038]
An ejection head unit 30 for applying liquid droplets is located above the substrate 14. In the present embodiment, the ejection head unit 30 is fixed, and the relative movement between the ejection head unit 30 and the substrate 14 is realized by moving the substrate 14 to an arbitrary position by the XY direction scanning mechanism 37.
[0039]
Next, the configuration of the ejection head unit 30 will be described with reference to FIG. The detection optical system 32 captures image information on the substrate 14, is close to the inkjet head 33 that ejects the droplet 42, and detects the optical axis 41 and the focal position of the detection optical system 32 and the droplet 42 by the inkjet head 33. Are arranged so as to coincide with the landing position 43.
[0040]
In this case, the positional relationship between the detection optical system 32 and the inkjet head 33 can be precisely adjusted by the head alignment fine movement mechanism 34 and the head alignment control mechanism 31. The detection optical system 32 uses a CCD camera and a lens.
[0041]
Returning to FIG. 4, the description will be continued. The image identification mechanism 36 identifies image information captured by the detection optical system 32, and has a function of binarizing an image contrast and calculating the position of the center of gravity of a binarized specific contrast portion. It is. Specifically, a high-precision image recognition device manufactured by Keyence Corporation; VX-4210 can be used. A means for providing the obtained image information with position information on the substrate 14 is a position detection mechanism 38. For this, a length measuring device such as a linear encoder provided in the XY direction scanning mechanism 37 can be used.
[0042]
A position correction control mechanism 39 performs position correction based on the image information and the position information on the substrate 14, and the movement of the XY direction scanning mechanism 37 is corrected by this mechanism. Further, the inkjet head 33 is driven by the inkjet head drive / control mechanism 40, and the liquid droplets are applied on the substrate 14. The above-described control mechanisms are centrally controlled by the control computer 35.
[0043]
In the above description, the discharge head unit 30 is fixed, and the relative movement between the discharge head unit 30 and the substrate 14 is realized by moving the substrate 14 to an arbitrary position by the XY direction scanning mechanism 37. Needless to say, as shown in FIG. 3, the substrate 14 may be fixed and the ejection head unit 30 may scan in the X and Y directions.
[0044]
In particular, when the present invention is applied to the production of an image forming apparatus having a medium screen of about 200 mm × 200 mm to a large screen of 2000 mm × 2000 mm or more, the substrate 14 is fixed as in the latter case, and the ejection head unit 30 has X, It is preferable that the scanning is performed in the two directions of Y, and the application of the liquid droplets is sequentially performed in such two orthogonal directions.
[0045]
When the substrate size is about 200 mm × 200 mm or less, the ejection head unit for applying droplets is of a large array multi-nozzle type capable of covering a range of 200 mm, and the relative movement between the ejection head unit and the substrate is perpendicular to two directions ( Relative movement can be performed only in one direction (for example, only in the X direction) without performing in the X direction and the Y direction, and mass productivity can be improved, but when the substrate size is 200 mm × 200 mm or more. It is difficult to technically and costly to manufacture a large array multi-nozzle type ejection head unit that can cover such a range of 200 mm. , Y so that the liquid droplets of the solution are sequentially applied in such two orthogonal directions. It is better to adopt a configuration in which
[0046]
As a material of the droplet 42, an aqueous solution, an organic solvent, or the like containing the above-described element or compound that becomes a conductive thin film can be used. For example, when the element or compound that forms the conductive thin film is a palladium-based element, a palladium acetate-ethanolamine complex (PA-ME), a palladium acetate-diethanol complex (PA-DE), and a palladium acetate-triethanolamine Aqueous solution containing an ethanolamine-based complex such as a complex (PA-TE), a palladium acetate-butylethanolamine complex (PA-BE), and a palladium acetate-dimethylethanolamine complex (PA-DME); Aqueous solution containing an amine acid complex such as Pd-Gly), a palladium-β-alanine complex (Pd-β-Ala), or a palladium-DL-alanine complex (Pd-DL-Ala); Butyl acetate solution of di-propylamine complex;
[0047]
More specifically, for example, in the case of an aqueous solution of palladium acetate-triethanolamine, it is produced as follows. That is, 50 g of palladium acetate is suspended in 500 cc of isopropyl alcohol, and 100 g of triethanolamine is further added, followed by stirring at 35 ° C. for 12 hours.
[0048]
After completion of the reaction, isopropyl alcohol is removed by evaporation, ethyl alcohol is added to the solid to dissolve and filter, and palladium acetate-triethanolamine is recrystallized from the filtrate. 10 g of the thus obtained palladium acetate-triethanolamine can be dissolved in 190 g of pure water to obtain a solution for injection.
[0049]
As another example, palladium fine particles are ozone-treated with an ozone generator having a voltage of 60 V, a frequency of 50 Hz and an oxygen flow rate of 40 ml / min, and 7 g of the treated palladium fine particles are converted into a solution of 5 g of ethylene glycol, 8 g of ethanol and 80 g of pure water. It can be dispersed to form a solution for jetting.
[0050]
As is clear from the above description, the electron source substrate of the present invention is manufactured by flying a solution containing an element or a compound to be a conductive thin film in the air by the principle of ink jet, and applying the solution as droplets on the substrate. However, in order to stably form a high-quality surface conduction electron-emitting device over a long period of time, the manufacturing apparatus must maintain a stable and constant performance.
[0051]
The most important point here is the long-term performance stability of the ejection head. As described above, in the present invention, the solution containing the material for forming the conductive thin film is a solution in which metal fine particles are dispersed in a liquid. However, these metal fine particles exist as abrasive grains dispersed in a solution, and when a large amount of this solution is used, there is a problem that the passage of the solution of the ejection head is damaged or worn. Among the passages, in particular, scratches and abrasion of the discharge port (nozzle) are problematic because they affect the droplet ejection performance of the solution.
[0052]
By the way, the scratches and wear are generated when two objects collide with each other or rub against each other. Therefore, it is considered that the scratches and the wear can be solved by appropriately selecting the hardness of the objects. Although it is true that the flaw also affects the droplet ejection performance of the ejection head, it is considered that the extent of the flaw depends on the size of the flaw and the size of the path of the solution. For example, even if there is a scratch on the nanometer order in a hose for water discharge having an inner diameter of Φ15 mm to Φ20 mm, it cannot have a great effect on the flow rate of water discharge.
[0053]
In the present invention, in consideration of these points, the hardness of the material of the discharge port, the hardness of the material of the metal fine particles, and the size of the discharge port are intensively studied.
Specifically, by using the ejection head as shown in FIG. 5 and using an ejection head in which a multi-nozzle plate is adhered to the surface of the rectangular nozzle portion 58 and performing solution ejection for a certain period of time, the ejection port portion ( It was examined whether or not scratches occur in the nozzle holes, and whether or not deterioration of the solution droplet ejection performance causes deterioration of the formed element shape (good or bad shape of the dot pattern) and deterioration of the element performance. The multi-nozzle plate was prepared by changing the material and the nozzle diameter (here, a round shape). The device performance was examined after performing a forming process and the like described later.
[0054]
The jet head used was of a thermal ink jet type using thermal energy. As described above, the jet head of FIG. 6 was equipped with a nozzle plate (nozzle plate is not shown). In this case, only four discharge ports are shown for simplicity of description. The number of ejection ports actually used was 64 and the arrangement density thereof was 400 dpi.
[0055]
The size of the heating element was 22 μm × 90 μm, its resistance was 111Ω, the driving voltage for droplet ejection was 24 V, the driving pulse width was 6.5 μs, and the driving frequency was 12 kHz. Injection was performed continuously for 100 hours, and the ejection port portion after the injection was observed by SEM to check for any scratches. Discharge diameters of Φ25 μm (H1), Φ16 μm (H2), and Φ10 μm (H3) were prepared. As a comparative reference example, one having a discharge opening diameter of Φ36 μm (reference head) was also prepared.
[0056]
In this case, the number of discharge ports is 48, and the arrangement density is 240 dpi. The size of the heating element was 35 μm × 150 μm, the resistance was 120 Ω, the driving voltage for ink ejection was 30 V, the driving pulse width was 7 μs, and the driving frequency was 3.8 kHz. The thickness of the nozzle plate was 30 μm for H1 and H2, 20 μm for H3, and 40 μm for the reference head. The velocity of the droplet at the time of ejection was about 8 m / s in each of the ejection heads.
[0057]
The nozzle plate was made of Ni and austenitic stainless steel SUS304. For the Ni material, a multi-nozzle plate was manufactured by an electroforming method. For the SUS304 material, a nozzle hole was formed by punching a stainless steel foil by electric discharge machining. When the hardness was measured by a Vickers hardness meter, the Vickers hardness Hv was 58 to 63 for the Ni material and 170 to 190 for the SUS304 material.
[0058]
The liquids used were S1 to S7 shown in Table 1 below, each showing the element name of the contained metal particles and the Vickers hardness Hv in the bulk state. The Vickers hardness Hv is a value from a metal data book (edited by The Japan Institute of Metals, 3rd revised edition, published by Maruzen). The content of the fine metal particles in each solution was about 7%, and the fine particle diameter was 150 ° to 200 °.
[0059]
[Table 1]

[0060]
The results of evaluation using these sample solutions and jet heads are shown in Tables 2 to 5 below. In the table, the mark ○ indicates that no noticeable scratch was observed after 100 hours of injection, and the mark 多数 indicates that there were a number of scratches that could affect the nozzle shape or dimensions. In the element shape, “○” indicates that the dot pattern was formed in a good round shape at the target position (between a pair of electrodes) when the element was manufactured after 100 hours of injection, and “×” indicates that the position was slightly targeted. They are out of place, irregular in shape, or have small droplets scattered around. × of the element performance is good (○) or not (×) of electron emission after performing a forming process or the like described later.
[0061]
[Table 2]

[0062]
[Table 3]

[0063]
[Table 4]

[0064]
[Table 5]

[0065]
From the above results, it is found that when the hardness of the contained metal fine particles is larger than the material of the discharge port (S3, S6), the discharge port is damaged. In addition, it can be seen that the element shape formed thereby is poor and the element performance is also poor. Therefore, when such a surface conduction electron-emitting device is formed by the manufacturing apparatus as in the present invention, it is understood that it is necessary to select a material which is softer than the material constituting the discharge port for the metal fine particles.
[0066]
Regarding the flaw, there is a case in which the element shape does not deteriorate depending on the size of the discharge port. Like the reference head, the discharge port diameter is as large as Φ36 μm (= the area is about 1000 μm). ² In such a case, since the diameter of the discharge port is large even if it is flawed, the flaw is not so large as to deteriorate the jetting performance, and a sufficiently usable element shape is obtained.
[0067]
On the other hand, the discharge port diameter is Φ25 μm or less (= the area is ² In the case of less than half of the reference head in the area comparison as in the case of (1), even if the flaw is similarly formed, the influence on the comparison with the discharge port diameter is large, and a good element shape and element It turns out that performance cannot be obtained.
[0068]
In other words, if a very fine surface conduction electron-emitting device is not formed, the problem of scratches does not affect the device performance, so there is no need to worry. However, as in the present invention, a liquid having a discharge port diameter of Φ25 μm or less is not required. In the case where a solution containing metal particles of 10 ° to 200 ° is sprayed and applied by a droplet spraying head to form a surface conduction type electron-emitting device group by a conductive thin film, the flaw of the discharge port portion is detrimental to the device performance. Since it is fatal, it is necessary to select a combination of a solution and a discharge port member that does not cause scratches. That is, the metal fine particles need to be made of a material softer than the member constituting the discharge port.
[0069]
In the experiment, a circular Φ25 μm nozzle (area of about 490 μm ² ), Φ16μm nozzle (area is about 200μm ² ), Φ10μm nozzle (area is about 80μm ² ), But when using a nozzle of another shape (for example, a rectangular shape) as the nozzle of the ejection head, the area of the nozzle may be compared. For example, a 22 μm × 22 μm nozzle may be replaced with the round shape of the present invention. Φ25 μm nozzle. In other words, the present invention has an area of 500 μm ² The present invention is applied to a case where such a solution is ejected by a jet head using nozzles smaller than the nozzles to form a surface conduction electron-emitting device group.
[0070]
Next, other features of the present invention will be described. As described above, in the present invention, the solution containing the material for forming the conductive thin film is a solution in which metal fine particles are dispersed in a liquid. The present invention also relates to a technique for forming a conductive thin film on a substrate by spraying the solution from a fine discharge port using a technique equivalent to the so-called inkjet spray principle. However, in the inks conventionally used in the ink jet recording field, the dye is dissolved in the solution, whereas in the solution used in the present invention, the metal fine particles are only dispersed in the solution, so clogging occurs. Cheap.
[0071]
Further, in the present invention, from the application of the required element (electron emitting element), a fine discharge port diameter which is not conventionally available, for example, the discharge port diameter is Φ25 μm or less (500 μm in terms of area) ² This clogging is a very serious problem.
[0072]
By the way, clogging is derived from the very principle that a solution is ejected from a fine discharge port. In other words, this is caused because the discharge port is fine. Therefore, there is a close relationship between the size of the discharge port and the size of the metal fine particles, which may be called foreign matters in the solution.
[0073]
In view of this point, the present invention pays attention to the size of the discharge port and the size of the metal fine particles, and finds out the relationship between the difficulty of clogging and the relationship therebetween. Specifically, a solution in which the diameter of the metal fine particles is changed is prepared, a droplet is ejected for a certain period of time using an ejection head having a known ejection port, and then left for a certain period of time, and the droplet ejection is resumed. The discharge port was examined for clogging. In this case, not only the complete obstruction of the discharge port, but also partial clogging and the prior signs (slight clogging) leading to it were considered as clogging and tested.
[0074]
The used ejection head is equivalent to a thermal ink jet system using thermal energy. As described above, the ejection head of FIG. 6 is provided with a nozzle plate (nozzle plate is not shown). FIG. 6 shows only four discharge ports for the sake of simplicity. Actually, the number of discharge ports is 128 and the arrangement density is 600 dpi. The size of the heating element was 20 μm × 85 μm, the resistance value was 105Ω, the driving voltage for droplet ejection was 22 V, the driving pulse width was 6 μs, and the driving frequency was 14 kHz.
[0075]
Note that the recording heads were prepared from H1 to H4 (the discharge port diameters were H1 = φ25 μm, H2 = φ20 μm, H3 = φ15 μm, and H4 = φ10 μm). The nozzle plate was formed by electroforming of Ni, and the thickness of the discharge port portion was all 30 μm.
[0076]
The solution used was subjected to ozone treatment of palladium fine particles with an ozone generator at a voltage of 60 V, a frequency of 50 Hz and an oxygen flow rate of 40 ml / min, and 7 g of the treated palladium fine particles were dispersed in a solution of 5 g of ethylene glycol, 8 g of ethanol and 80 g of pure water. As a solution for injection, a solution in which the diameter of palladium fine particles was changed from 0.0003 to 0.5 μm was prepared and tested in combination with H1 to H4 having different discharge port diameters. The condition for leaving the liquid droplets after spraying them for a certain period of time (for 10 minutes) is to leave them in an atmosphere at a temperature of 40 ° C. and a humidity of 30% for 10 hours.
[0077]
Tables 6 to 9 below show the results of examining the occurrence of clogging by combining these solutions in which the diameter of the palladium fine particles was changed and the heads H1 to H4 in which the discharge port diameter was changed. Table 6 is for the head H1 (discharge port diameter Do = Φ25 μm), Table 7 is for the head H2 (discharge port diameter Do = Φ20 μm), Table 8 is for the head H3 (discharge port diameter Do = Φ15 μm), and Table 9 is The case of the head H4 (discharge port diameter Do = Φ10 μm) is shown. In the judgment, a circle indicates a case where it can be practically used satisfactorily, a triangle indicates a case where it can be used but is not so preferable, and a cross indicates a case where it is not practical at all. When the fine palladium particles had a diameter of 0.0005 μm or less, they could not be dispersed stably and could not be evaluated.
[0078]
[Table 6]

[0079]
[Table 7]

[0080]
[Table 8]

[0081]
[Table 9]

[0082]
From the above results, in the case where the ejection head having the ejection diameter of Φ10 μm to Φ25 μm is used, clogging does not occur if the relationship between the diameter Pp of the fine palladium particles and the ejection diameter Do is set to satisfy the relationship of Dp / Do ≦ 0.01. It can be seen that stable droplet ejection can be obtained.
[0083]
Although the lower limit of Dp / Do is considered, it is difficult to make the fine palladium fine particle diameter Dp 0.0005 μm or less in consideration of stably dispersing such extremely fine metal fine particles in a solution. In order to stably eject droplets to all ejection heads having an ejection diameter of 25 μm or less, the lower limit may be set to 0.0001 with a margin.
[0084]
That is, if the relationship between the fine metal particle diameter Dp and the discharge port diameter Do satisfies the relationship of 0.0001 ≦ Dp / Do ≦ 0.01, the conductivity by droplet discharge using a discharge head having a discharge port diameter of 25 μm or less is obtained. It can be seen that a stable dispersion liquid capable of forming a conductive thin film can be produced and clogging can be prevented.
[0085]
In this experiment, a round discharge port (nozzle) was used. However, as described above, in the case of another shape, the area may be compared. For example, in the case of a rectangular discharge port of 22 μm × 22 μm, This is equivalent to the round φ25 μm nozzle of the present invention. In other words, the present invention has an area of 500 μm ² The present invention is applied to a case where such a solution is ejected by a jet head using nozzles smaller than the nozzles to form a surface conduction electron-emitting device group.
[0086]
In the experiment, a thermal inkjet (bubble jet (registered trademark)) type ejection head was used, but the ejection head used in the manufacturing apparatus of the present invention is not limited to this, and a piezo jet type using a piezoelectric element is used. Or a system using electrostatic force or a charge control system (continuous flow system).
[0087]
For example, in the case of a piezo jet system using a piezoelectric element, a round uniform droplet is obtained at the time of flying a droplet by always keeping the input voltage to the piezo element constant, and a good round dot is obtained on the substrate. Further, since heat is not used unlike the thermal ink jet method, there is an advantage that the solution to be used is not thermally degraded and the limitation of the solution to be used is small.
[0088]
On the other hand, in the case of the thermal ink jet system, the solution flies along with small satellite droplets when the solution flies, but the speed at the time of the flight is high (for example, 10 m / s to 20 m / s), and the merit that stable jetting is obtained. There is. As a result, minute satellite droplets also fly at high speed (10 m / s to 20 m / s) and adhere to the same location on the substrate.
[0089]
In other words, in the case of the thermal ink jet method, even if minute satellite droplets fly like flying, if the input energy to the heating element is always kept constant, the total solution volume for forming one dot is It is the same (because it adheres to the same place), and similarly good round dots are obtained.
[0090]
Next, still another feature of the present invention will be described. The present invention is a technology for manufacturing an electron-emitting device, and an electron-emitting device portion to be formed is usually a solution in which metal fine particles are dispersed on a pair of electrode patterns previously formed on a substrate. By spraying, a round dot pattern is formed, and an electron-emitting device is formed.
What is important here is the quality at the time when a solution in which metal fine particles are newly dispersed is sprayed onto the previously formed pattern, and the pattern is electrically connected to the previous electrode pattern. This will be described with reference to FIG.
[0091]
FIG. 7 shows a case where a solution in which metal fine particles are dispersed is jetted between two ITO transparent electrodes formed on a substrate to form a round dot pattern and form an electron-emitting device. It is a schematic diagram. In the drawing, Ld is the dot diameter when dots are formed alone on the substrate.
[0092]
FIG. 7A shows a case where a solution in which metal fine particles are dispersed is jetted between two ITO transparent electrodes to form a dot pattern. However, the space between the two ITO transparent electrodes is barely at the left and right ends of the dot pattern. This is an example of electrical connection. FIG. 7B is an example in which the dots overlap each other in the peripheral portion and are electrically connected to each other, as compared with the case of FIG. 7A, and the length of the overlap region is represented by Lc. FIGS. 7C and 7D show the case where the overlapping area Lc is large.
[0093]
Here, from the viewpoint of simply obtaining the electrical connection, in the case of FIGS. 7A to 7D, all of the connections can be made for the time being. However, in the case of FIGS. 7A and 7B, although they are connected for the time being, they are disconnected at the same time as the input of the electric signal. Or, even if the wire is not broken immediately, the contact resistance of the connection is too high, causing abnormal heat generation.Therefore, there is no long-term reliability. Can not.
[0094]
In the present invention, in order to solve this, in such a connection region, when a dot pattern is formed by subsequently spraying a solution in which metal fine particles are dispersed with respect to the pattern previously formed on the substrate, As shown in FIGS. 7 (C) and 7 (D), the dot at the end is formed by being driven so as to cover more than half of one dot over the pattern formed earlier.
In other words, when the dot diameter when a dot is formed alone is Ld, the size of the ejection port (Ld / Lc is satisfied so that Ld / 2 ≦ Lc is satisfied) Solution injection amount) and the driving method.
[0095]
This will be described with another example. 8 and 9, the electron emission portions between the pair of electrodes are not arranged in a straight line as in FIG. 7, but have a pattern arrangement in which the electron emission portions are orthogonal to each other. However, it is needless to say that the present invention is not necessarily limited to such a pattern arrangement, and may be configured as shown in FIG.
[0096]
FIG. 8 shows two ITO transparent electrode patterns formed on the substrate. This pattern was formed by a so-called photolithography technique called sputtering and etching. As shown in FIG. 9, an Ag fine particle-containing solution was overprinted using a jet head in which a dot diameter of about Φ12 μm was obtained by shifting the center distance (dot pitch) by about 3 μm. Was formed.
In this case, the distance between the overlapping region with the ITO transparent electrode pattern was set to about 13 μm (Lcx) and 8 μm (Lcy), and the dots were overlapped and connected by more than half of one dot diameter. As a result, a stable pattern is obtained without disconnection for a long time.
[0097]
FIG. 10 shows another example. In this case, the previously formed pattern is also formed by a dot pattern formed by spraying a solution in which the metal fine particles of the present invention are dispersed. Also in this case, as shown in FIG. 11, the overlapping areas (Lcx, Lcy) of the dot patterns to be formed later were connected so as to overlap at least half the dot diameter of the dots.
[0098]
In this example, the first dot pattern and the second dot pattern have the same dot diameter, but they may have different dot diameters as necessary. In particular, in the case where a pattern having a large area ahead is formed instead of a thin wiring line, it is more efficient to obtain a large dot diameter by an ejection head having a large nozzle diameter.
In addition, here, the two electrodes are experimentally described using an example of an ITO transparent electrode, but are not necessarily limited to ITO, and materials such as Al, Au, and Cu can be suitably used.
[0099]
Next, still another feature of the present invention will be described with reference to FIGS. FIG. 12 is an enlarged view of FIG. 2B shown above. FIG. 13 shows respective regions of the pattern of the conductive thin film 4 for explaining the features of the present invention. In the present invention, the conductive thin film 4 is formed by spraying a solution in which metal fine particles are dispersed between the device electrodes 2 and 3 to form a dot pattern and then drying the dot pattern. In this case, the problem is the step coverage of the conductive thin film 4 at the edge of the pattern of the device electrodes 2 and 3 formed earlier.
[0100]
As shown in FIG. 13A, in part A, there is a step in the pattern of the device electrode formed earlier, so that a solution in which fine metal particles are dispersed is jetted later to form the conductive thin film 4. When formed, there is a problem that good coating cannot be obtained at the edge portion. For this reason, disconnection may occur at the portion, and the durability of the electron-emitting device may be impaired, the reliability is low, and there is a problem in practical use.
[0101]
In view of this point, in the present invention, the thickness of the conductive thin film 4 formed by spraying a solution in which fine metal particles are dispersed is sprayed in this region, that is, in the pattern edge portion of the element electrode previously formed on the substrate. The ejection head is controlled so as to be thicker than the other region (the portion B in FIG. 13B) which is not the edge portion.
[0102]
Specifically, when the solution is jetted to the region A, the input energy to the piezo element or the heating element is increased in the jetting head applied to the present invention, and the jetting is performed to the region B. By increasing the size of the droplet or the mass of the flying liquid, the film thickness formed there (region A) can be increased.
[0103]
More specifically, the thickness of the element electrode pattern is set to, for example, 300 °, a solution in which metal fine particles are dispersed is sprayed to form a conductive thin film 4, and the volatile component in the solution is dried. When the final thickness after drying is set to 200 °, if the ejection head is controlled so that the thickness of the region A is set to 300 ° to 500 °, the step coverage is good and even if used for a long time. A highly reliable electron-emitting device without disconnection or the like can be obtained.
[0104]
As is apparent from the above description, the present invention is a technique for manufacturing an electron-emitting device. However, a very fine pattern of several tens μm to several μm is not formed by a conventional photolithography technique, but is formed by a conventional technique. The electron emission element group is directly manufactured by a simple device in which a solution in which metal fine particles are dispersed is directly applied to a substrate by an ejection head having no minute discharge ports. Therefore, there is an advantage that the production can be performed stably at low cost without requiring expensive production equipment used in a so-called semiconductor production process.
[0105]
After the pattern of the surface conduction electron-emitting device group having a good shape is formed in this way, the electron-emitting portion 5 is formed by a forming process described below in the present invention (FIGS. 1 and 2). reference).
[0106]
The electron-emitting portion 5 is constituted by a high-resistance crack formed in a part of the conductive thin film 4 and depends on the film thickness, film quality, material, etc. of the conductive thin film 4 or the forming condition. In some cases, the inside of the electron emitting portion 5 contains conductive fine particles having a particle size of 100 ° or less.
[0107]
As an example of the forming method applied to the conductive thin film 4, a method using an energization process will be described. When an electric current is applied between the device electrodes 2 and 3 using a power supply (not shown), an electron emitting portion 5 having a changed structure is formed at the portion of the conductive thin film 4. That is, according to the energization forming, a portion of the conductive thin film 4 where a structural change such as destruction, deformation or alteration is locally formed, and this portion becomes the electron emission portion 5.
[0108]
FIG. 14 is a diagram showing an example of a voltage waveform of the energization forming process as described above applied to the present invention. The voltage waveform is particularly preferably a pulse waveform. A voltage pulse having a constant pulse peak value is continuously applied (FIG. 14A), and a voltage pulse is applied while increasing the pulse peak value (FIG. 14). (B)). First, the case where the pulse crest value is a constant voltage (FIG. 14A) will be described.
[0109]
T1 and T2 in FIG. 14A are the pulse width and pulse interval of the voltage waveform, respectively, T1 is 1 μs to 10 ms, T2 is 10 μs to 100 ms, and the peak value of the triangular wave (peak voltage at the time of energization forming) is surface conduction. It is appropriately selected according to the form of the electron-emitting device. Under such conditions, for example, a voltage is applied for several seconds to tens of minutes. Further, the pulse waveform is not limited to a triangular wave, and a desired waveform such as a rectangular wave may be used.
[0110]
T1 and T2 in FIG. 14B indicate the pulse width and pulse interval of the voltage waveform, respectively, as in FIG. 14A, and the peak value of the triangular wave (peak voltage during energization forming) is, for example, It can be increased by about 0.1 V steps.
[0111]
The end of the energization forming process can be detected by applying a voltage that does not locally destroy or deform the conductive thin film 4 during the pulse interval T2, and measuring the current. For example, the element current flowing when a voltage of about 0.1 V is applied is measured, and the resistance value is calculated. When the resistance value indicates 1 MΩ or more, the energization forming is terminated.
[0112]
It is desirable to apply a process called an activation process to the element after the energization forming. By performing the activation process, the element current If and the emission current Ie change significantly. The activation step can be performed, for example, by repeating the application of a pulse in an atmosphere containing an organic substance gas, similarly to the energization forming.
[0113]
The above atmosphere can be formed by utilizing an organic gas remaining in the atmosphere when the inside of the vacuum vessel is discarded using, for example, an oil diffusion pump or a rotary pump, or sufficiently exhausted once by an ion pump or the like. It can also be obtained by introducing a gas of an appropriate organic substance into a vacuum. The preferable gas pressure of the organic substance at this time varies depending on the above-described application form, the shape of the vacuum vessel, the type of the organic substance, and the like, and is appropriately set according to the case.
[0114]
Examples of the organic substance include alkanes, alkenes, alkyne aliphatic hydrocarbons, aromatic hydrocarbons, alcohols, aldehydes, ketones, amines, phenols, carboxylic acids, and organic acids such as sulfonic acids. And specifically, C 4, such as methane, ethane, and propane. _n H _{2n + 2} C, such as saturated hydrocarbons, ethylene and propylene represented by _n H _2n And the like. Unsaturated hydrocarbons represented by a composition formula such as benzene, toluene, methanol, formaldehyde, acetaldehyde, acetone, methyl ethyl ketone, methylamine, ethylamine, phenol, formic acid, acetic acid, propionic acid and the like can be used.
[0115]
By this treatment, carbon or a carbon compound is deposited on the device from the organic substance existing in the atmosphere, and the device current If and the emission current Ie are significantly changed. The end of the activation step is determined while measuring the element current If and the emission current Ie. Note that the pulse width, pulse interval, pulse crest value, and the like are set as appropriate.
[0116]
The carbon or carbon compound is graphite (refer to both single crystal and polycrystal), amorphous carbon (carbon including amorphous carbon and a mixture of amorphous carbon and the fine crystal of graphite), and The film thickness is preferably not more than 500 °, more preferably not more than 300 °.
[0117]
It is preferable that the electron-emitting device thus manufactured is subjected to a stabilization process. In this process, the partial pressure of the organic substance in the vacuum vessel is reduced to 1 × 10 ^-8 Torr or less, desirably 1 × 10 ^-10 It is better to perform the process at Torr or less. The pressure in the vacuum vessel is 10 ^-6 -10 ^-7 Torr or less, preferably 1 × 10 ^-8 Torr or less is preferable. It is preferable to use a vacuum evacuation device that does not use oil so that the oil generated from the device does not affect the characteristics of the element.
[0118]
Specifically, a vacuum exhaust device such as a sorption pump or an ion pump can be used. Further, when evacuating the inside of the vacuum vessel, it is preferable to overheat the entire vacuum vessel to facilitate evacuating the organic substance molecules adsorbed on the inner wall of the vacuum vessel and the electron-emitting device. The vacuum evacuation conditions in the heated state at this time are desirably 5 hours or more at 80 to 200 ° C., but are not particularly limited to these conditions, and various conditions such as the size and shape of the vacuum vessel and the configuration of the electron-emitting device. It changes with.
[0119]
The partial pressure of the organic substance is determined by measuring partial pressures of organic molecules having carbon and hydrogen having a mass number of 10 to 200 as a main component by a mass spectrometer, and integrating the partial pressures. After the stabilization step, it is preferable that the atmosphere at the time of driving maintain the atmosphere at the end of the stabilization treatment.However, the present invention is not limited to this.If the organic substance is sufficiently removed, the degree of vacuum itself is reduced. Even if it is slightly reduced, it is possible to maintain sufficiently stable characteristics. By employing such a vacuum atmosphere, deposition of new carbon or a carbon compound can be suppressed, and as a result, the device current If and the emission current Ie are stabilized.
[0120]
The production and forming of the electron-emitting device of the present invention are performed as described above, and thereafter, the electron-emitting device is used as an image forming apparatus (display) as described later. However, there is one problem here. This is a problem in the above-described forming process or when the device is used as a display, but it is an abnormal discharge in the element electrode portion.
[0121]
This will be described with reference to FIG. In the present invention, as shown in FIG. 15, an electron-emitting portion is formed by a dot pattern of a solution containing a metal fine particle material between a plurality of (in this example, two) opposed device electrodes. It is composed of a rectangular pattern or a combination of rectangular patterns. This is because the device electrode pattern is formed in a rectangular shape (a rectangle is most easily manufactured at a low cost) depending on the shape of the photomask when the device electrode pattern is formed by the photolithography technique. As shown in (A), the corners of the two opposing element electrodes are sharp, so that electric field concentration occurs at those points.
[0122]
As a result, the voltage is applied between both electrodes by the forming process, or the voltage is applied between both electrodes even when the device is finally used as a display. There is a problem that the image quality of the display is degraded due to inability to perform the operation or abnormal electron emission.
[0123]
In view of this point, in the present invention, for example, as shown in FIG. In this example, a c-shaped chamfer when displayed on a mechanical drawing is used, but it goes without saying that an r-shaped chamfer may be used.
[0124]
Such a shape may be such that the shape of the photomask does not become sharp at such corners when the element electrode pattern is formed by photolithography. Alternatively, as described with reference to FIG. 10, if the device electrode is formed by a dot pattern formed by spraying a solution in which the metal fine particles of the present invention are dispersed, the outer shape of the dot pattern itself has a round shape and a sharp portion. Because there is no, it can be automatically formed into a chamfered shape.
[0125]
If the size of the chamfered portion is about １ ／ to ５ of the diameter of the dot pattern forming the electron-emitting portion, that is, c2 μm to c5 μm, or r2 μm to r5 μm, a favorable element which does not cause electric field concentration. It can be an electrode.
[0126]
In the present invention, by eliminating the sharp portions of the device electrodes and eliminating the electric field concentration, no abnormal discharge occurs during the forming process or when the device is used as a display as described later, and for a long time. Even when used, stable and good electron emission can be obtained, and a high-quality display can be obtained.
[0127]
Next, the image forming apparatus of the present invention will be described. Various arrangements of the electron-emitting devices on the electron source substrate used in the image forming apparatus can be employed. First, each of a large number of electron-emitting devices arranged in parallel is connected at both ends, a large number of rows of electron-emitting devices are arranged (referred to as a row direction), and electrons are arranged in a direction (called a column direction) orthogonal to the wiring. There is a ladder-like arrangement in which electrons from the electron-emitting device are controlled and driven by a control electrode (also called a grid) arranged above the emitting device.
[0128]
Separately, a plurality of electron-emitting devices are arranged in a matrix in the X and Y directions, and one of the electrodes of the plurality of electron-emitting devices arranged in the same row is commonly connected to a wiring in the X direction. One in which the other of the electrodes of the plurality of electron-emitting devices arranged in the same column is commonly connected to a wiring in the Y direction. Such is the so-called simple matrix arrangement. First, the simple matrix arrangement will be described in detail below.
[0129]
FIG. 16 is a view showing an example of an electron source substrate obtained by arranging a plurality of electron-emitting devices in a matrix. In the drawing, reference numeral 10 denotes an electron source substrate, 14 denotes a substrate, 61 denotes an X-direction wiring, and 62 denotes a Y-direction. Directional wiring, 63 is a surface conduction electron-emitting device, and 64 is a connection. The X direction wiring 61 is composed of m wirings DX1, DX2,... DXm, and the Y direction wiring 62 is composed of n wirings DY1, DY2,. Further, the material, the film thickness, and the wiring width are appropriately set so that a substantially uniform voltage is supplied to a large number of surface conduction type elements 63. The m X-directional wirings 61 and the n Y-directional wirings 62 are electrically separated by an interlayer insulating layer (not shown) to form a matrix wiring (m and n are both positive integers). ).
[0130]
The interlayer insulating layer (not shown) is formed on the entire surface of the substrate 14 on which the X-directional wiring 61 is formed or on a part of a desired region. The X-direction wiring 61 and the Y-direction wiring 62 are led out as external terminals. Further, the device electrodes (not shown) of the surface conduction electron-emitting device 63 are electrically connected to the m X-directional wires 61 and the n Y-directional wires 62 by a connection 64. The material forming the X-direction wiring 61 and the Y-direction wiring 62, the material forming the connection 64, and the material forming the pair of element electrodes are different even if some or all of the constituent elements are the same. May be.
These materials are appropriately selected, for example, from the above-described materials for the device electrodes. When the material forming the element electrode is the same as the wiring material, the element electrode can be referred to as the element electrode including the wiring connected to the element electrode.
[0131]
The X-direction wiring 61 is electrically connected to a scanning signal generating means (not shown) for applying a scanning signal for scanning a row of the surface conduction electron-emitting devices 63 arranged in the X direction according to an input signal. On the other hand, the Y-direction wiring 62 is electrically connected to a modulation signal generating means (not shown) for applying a modulation signal for modulating each column of the surface conduction electron-emitting devices 63 arranged in the Y direction according to an input signal. ing.
[0132]
Further, the driving voltage applied to each element of the surface conduction electron-emitting device 63 is supplied as a difference voltage between a scanning signal and a modulation signal applied to the element. As a result, individual elements can be selected and driven independently using only a simple matrix wiring.
[0133]
Next, an image forming apparatus using an electron source having a simple matrix arrangement created as described above will be described. FIG. 17 is a view for explaining an example of the basic configuration of the display panel of the image forming apparatus. In the figure, reference numeral 10 denotes an electron source substrate in which an electron-emitting device 63 is formed on a substrate; A rear plate 72 is a support frame, and 76 is a face plate in which a fluorescent film 74 and a metal back 75 are formed on the inner surface of a glass substrate 73. Frit glass or the like is applied to the rear plate 71, the support frame 72 and the face plate 76. The envelope 78 is formed by baking in air or nitrogen at 400 to 500 degrees for 10 minutes or more to seal.
[0134]
In FIG. 17, reference numeral 63 denotes an electron-emitting device corresponding to the configuration shown in FIG. 1, and reference numerals 61 and 62 denote X-direction wiring and Y-direction wiring connected to a pair of device electrodes of the surface conduction electron-emitting device, respectively.
[0135]
The envelope 78 includes the face plate 76, the support frame 72, and the rear plate 71 as described above. However, since the rear plate 71 is provided mainly for the purpose of reinforcing the strength of the electron source substrate 10, the If it has sufficient strength, the separate rear plate 71 is unnecessary, and the support frame 72 is directly sealed to the electron source substrate 10, and is externally connected to the face plate 76, the support frame 72, and the electron source substrate 10. The enclosure 78 may be configured.
Further, by installing an anti-atmospheric pressure support member called a spacer between the face plate 76 and the rear plate 71, an envelope 78 having sufficient strength against atmospheric pressure can be formed.
[0136]
In any case, since such a face plate is laminated and integrated with the electron source substrate to form an image forming apparatus (image display device), it has substantially the same shape and size as the electron source substrate.
[0137]
FIG. 18 is a schematic diagram showing a configuration example of a fluorescent film used in the image forming apparatus of FIG. 17. FIG. 18A shows a black stripe type fluorescent film, and FIG. 18B shows a black matrix type fluorescent film. It is shown in FIG. In FIG. 18, 74 is a fluorescent film, 81 is a black conductive material, and 82 is a phosphor.
[0138]
The fluorescent film 74 is made of only a phosphor in the case of a monochrome, but is composed of a black conductive material 81 called a black stripe or a black matrix and a phosphor 82 depending on the arrangement of the phosphor in the case of a color fluorescent film. . The purpose of providing a black stripe and a black matrix is to make the color separation between the phosphors 82 of the necessary three primary color phosphors black in the case of color display so that color mixing and the like become inconspicuous, The purpose is to suppress a decrease in contrast due to light reflection.
[0139]
The material of the black stripe is not limited to the commonly used material containing graphite as a main component, as long as it is conductive and has little light transmission and reflection.
[0140]
In the present invention, the directions of the stripes of the matrix 82 of the phosphors 82 or the two orthogonal directions of the matrix and the two orthogonal directions of the electron-emitting device 63 are parallel to each other. The phosphors 82 are positioned and laminated so as to coincide with the electron-emitting devices 63 to constitute an image display device.
In the image display device having such a configuration, the directions and positions of the matrices match each other, so that an image display device with extremely high image quality can be realized.
[0141]
As a method of applying the phosphor on the glass substrate 73, a precipitation method or a printing method is used regardless of monochrome or color. A metal back 75 is usually provided on the inner surface side of the fluorescent film 74 (FIG. 18).
[0142]
The metal back 75 improves the brightness by mirror-reflecting the light toward the inner surface side of the light emitted from the phosphor toward the face plate 76, acts as an electrode for applying an electron beam acceleration voltage, It has a role of protecting the phosphor from damage due to collision of negative ions generated in the vessel. The metal back 75 can be manufactured by performing a smoothing process (usually called filming) on the inner surface of the fluorescent film 74 after manufacturing the fluorescent film 74, and then depositing Al by vacuum evaporation or the like. Further, a transparent electrode (not shown) may be provided on the face plate 76 on the outer surface side of the fluorescent film 74 in order to further increase the conductivity of the fluorescent film 74.
[0143]
When performing sealing for forming the above-described envelope 78, in the case of color, the phosphors 82 of each color must correspond to the electron-emitting devices 63, and it is necessary to perform sufficient alignment. In order to perform this sufficient alignment, according to the present invention, as described above, the phosphor 82 is arranged at a position facing the electron-emitting device 63, and the matrix of the electron-emitting device 63 and the phosphor 82 are orthogonal to each other. The two directions are parallel to each other.
In order to obtain a highly accurate image display device having such a configuration, it is desirable that the phosphor substrate also employs the same positioning method as the electron source substrate of the present invention.
[0144]
The image forming apparatus shown in FIG. 17 is specifically manufactured as follows. The envelope 78 is evacuated through an exhaust pipe (not shown) by an exhaust device that does not use oil, such as an ion pump and a sorption pump, while appropriately heating, as in the above-described stabilization process. ^-7 After the atmosphere of an organic substance having a degree of vacuum of about Torr is sufficiently reduced, sealing is performed.
[0145]
In some cases, getter processing is performed to maintain the degree of vacuum after the envelope 78 is sealed. This is done by heating a getter disposed at a predetermined position (not shown) in the envelope 78 by a heating method such as resistance heating or high-frequency heating immediately before or after the sealing of the envelope 78, and performing vapor deposition. This is a process for forming a film. The getter is usually composed mainly of Ba or the like. ^-5 Torr or 1 × 10 ^-7 It maintains the degree of vacuum of Torr.
[0146]
Next, a schematic configuration showing an example of a drive circuit for driving a display panel formed using an electron source having a simple matrix arrangement type substrate and performing television display based on an NTSC television signal will be described. FIG. 19 is a block diagram of a driving circuit for performing display according to an NTSC television signal, and shows an image forming apparatus including the driving circuit. 19, reference numeral 91 denotes an image display panel, 92 denotes a scanning circuit, 93 denotes a control circuit, 94 denotes a shift register, 95 denotes a line memory, 96 denotes a synchronization signal separation circuit, 97 denotes a modulation signal generator, and Vx and Va denote DC. It is a voltage source.
[0147]
Hereinafter, the function of each unit shown in FIG. 19 will be described. The display panel 91 is connected to an external electric circuit via terminals Dox1 to Doxm, terminals Doy1 to Doyn, and a high voltage terminal Hv. Of these terminals, the terminals Dox1 to Doxm sequentially drive electron sources provided in the display panel 91, that is, a group of surface conduction electron-emitting devices arranged in a matrix of M rows and N columns, one row at a time (N elements). A scanning signal for moving is applied.
[0148]
On the other hand, to the terminals Doy1 to Doyn, a modulation signal for controlling the output electron beam of each element of the one row of surface conduction electron-emitting devices selected by the scanning signal is applied. Further, a DC voltage of, for example, 10 kV is supplied to the high voltage terminal Hv from the DC voltage source Va, which applies sufficient energy to the electron beam output from the surface conduction electron-emitting device to excite the phosphor. Is the accelerating voltage for
[0149]
Next, the scanning circuit 92 will be described. This circuit has M switching elements inside (in the figure, S1 to Sm are schematically shown), and each switching element is either an output voltage of a DC voltage source Vx or 0 V (ground level). One is selected and electrically connected to the terminals Dox1 to Doxm of the display panel 91.
[0150]
Each of the switching elements S1 to Sm operates based on the control signal Tscan output from the control circuit 93, but can be actually configured by combining switching elements such as FETs. In the DC voltage source Vx, the drive voltage applied to an unscanned element becomes equal to or lower than the electron emission threshold voltage based on the characteristics (electron emission threshold voltage) of the surface conduction type electron emission element. It is set to output such a constant voltage.
[0151]
The control circuit 93 has a function of matching the operation of each unit so that appropriate display is performed based on an image signal input from the outside. Based on a synchronizing signal Tsync sent from a synchronizing signal separating circuit 96 described later, each control signal of Tscan, Tsft and Tmry is generated for each unit.
[0152]
The synchronizing signal separating circuit 96 is a circuit for separating a synchronizing signal component and a luminance signal component from an NTSC television signal input from the outside, and can be configured by using a frequency separating (filter) circuit. The synchronizing signal separated by the synchronizing signal separating circuit 96 is composed of a vertical synchronizing signal and a horizontal synchronizing signal as is well known, but is shown here as a Tsync signal for convenience of explanation. On the other hand, the luminance signal component of the image separated from the television signal is referred to as a DATA signal for convenience, and the signal is input to the shift register 94.
[0153]
The shift register 94 performs serial / parallel conversion of the DATA signal input serially in time series for each line of an image, and operates based on a control signal Tsft sent from the control circuit 93. That is, the control signal Tsft may be rephrased as a shift clock of the shift register 94. The data of one line of the serial / parallel-converted image (corresponding to the drive data of N electron-emitting devices) is output from the shift register 94 as N parallel signals Id1 to Idn.
[0154]
The line memory 95 is a storage device for storing data for one line of an image for a required time only, and stores the contents of Id1 to Idn as appropriate according to a control signal Tmry sent from the control circuit 93. The stored contents are output as Id'1 to Id'n and input to the modulation signal generator 97.
[0155]
The modulation signal generator 97 is a signal source for appropriately driving and modulating each of the surface conduction electron-emitting devices in accordance with each of the image data Id'1 to Id'n. The voltage is applied to the surface conduction electron-emitting device in the display panel 91 through Doyn.
[0156]
As described above, the electron-emitting device according to the present invention has the following basic characteristics with respect to the emission current Ie. That is, as described above, electron emission has a clear threshold voltage Vth, and electron emission occurs only when a voltage higher than Vth is applied. For a voltage equal to or higher than the electron emission threshold, the emission current also changes according to the change in the voltage applied to the element. In some cases, the value of the electron emission threshold voltage Vth or the degree of change of the emission current with respect to the applied voltage may be changed by changing the material, configuration, or manufacturing method of the electron emission element. I can say that.
[0157]
In other words, when a pulse-like voltage is applied to the device, for example, when a voltage lower than the electron emission threshold is applied, electron emission does not occur. A beam is output. At that time, first, the intensity of the output electron beam can be controlled by changing the peak value Vm of the pulse, and second, the electron beam output by changing the width Pw of the pulse can be controlled. Can be controlled.
[0158]
Therefore, as a method of modulating the electron-emitting device in accordance with the input signal, there are a voltage modulation method, a pulse width modulation method, and the like. To implement the voltage modulation method, the modulation signal generator 97 must have a fixed length. The voltage pulse is generated by using a voltage modulation type circuit that modulates the peak value of the pulse appropriately according to the input data. In order to implement the pulse width modulation method, the modulation signal generator 97 generates a voltage pulse having a constant peak value, but a pulse width that modulates the width of the voltage pulse appropriately according to input data. A modulation type circuit is used.
[0159]
The shift register 94 and the line memory 95 may be of a digital signal type or an analog signal type, as long as the serial / parallel conversion and storage of the image signal are performed at a predetermined speed.
[0160]
When a digital signal type is used, the output signal DATA of the synchronization signal separation circuit 96 needs to be converted into a digital signal. This can be achieved by providing an A / D converter at the output of the synchronization signal separation circuit 96. It is possible. In connection with this, the circuit used for the modulation signal generator 97 is slightly different depending on whether the output signal of the line memory 95 is a digital signal or an analog signal.
[0161]
First, the case of a digital signal will be described. In the voltage modulation method, for example, a well-known D / A conversion circuit may be used as the modulation signal generator 97, and an amplification circuit or the like may be added as necessary. In the case of the pulse width modulation method, the modulation signal generator 97 compares, for example, a high-speed oscillator, a counter (counter) for counting the number of waves output by the oscillator, and the output value of the counter with the output value of the line memory 95. It can be configured by using a circuit in which a comparator (comparator) is combined. If necessary, an amplifier for amplifying the pulse width modulated signal output from the comparator to the drive voltage of the surface conduction electron-emitting device may be added.
[0162]
Next, the case of an analog signal will be described. In the voltage modulation method, for example, an amplification circuit using a well-known operational amplifier may be used as the modulation signal generator 97, and a level shift circuit or the like may be added as necessary. In the case of the pulse width modulation system, for example, a well-known voltage controlled oscillator (VCO) may be used, and an amplifier for amplifying the voltage up to the driving voltage of the surface conduction electron-emitting device may be added as necessary. May be.
[0163]
In the image display device having the above-described configuration, a voltage is applied to each of the electron-emitting devices of the display panel 91 through terminals Dox1 to Doxm and Doy1 to Doyn outside the container, thereby causing electrons to be emitted and the high-voltage terminal Hv , A high voltage is applied to the metal back 75 or a transparent electrode (not shown) to accelerate the electron beam, collide with the fluorescent film 74, and excite and emit light to display an image.
[0164]
The configuration described here is a schematic configuration necessary for manufacturing a suitable image forming apparatus used for display and the like, and detailed portions such as materials of each member are not limited to those described above. It is appropriately selected so as to be suitable for the use of the forming apparatus. Although the NTSC system has been described as an example of the input signal, the present invention is not limited to this, and various systems such as the PAL and SECAM systems may be used. In addition, a TV signal composed of a larger number of scanning lines (for example, MUSE) And other high-definition TV) systems.
[0165]
Next, the ladder-type arranged electron source substrate and the image display device will be described. FIG. 20 is a schematic view showing a configuration example of an electron source substrate in which electron emission elements are arranged in a ladder shape. In the figure, 100 is an electron source substrate, 14 is a substrate, 63 is an electron emission element, and 98 is an electron emission element 63 Is a common wiring composed of Dx1 to Dx10 connected to the common wiring. A plurality of electron-emitting devices 63 are arranged on the substrate 14 in parallel in the X direction (this arrangement is called an element row).
[0166]
A plurality of the element rows are arranged on a substrate to form an electron source substrate 100. By applying a drive voltage between the common wires of each element row, each element row can be driven independently. That is, a voltage equal to or higher than the electron emission threshold may be applied to an element row in which an electron beam is to be emitted, and a voltage equal to or lower than the electron emission threshold may be applied to an element row in which an electron beam is not emitted. Further, the common wirings Dx2 to Dx9 between the element rows, for example, Dx2 and Dx3 may be the same wiring.
[0167]
FIG. 21 is a view for explaining a panel structure in an image display device provided with a ladder-type arrangement electron source substrate as shown in FIG. 20. In the figure, reference numeral 100 denotes an electron in which a common wiring between element rows is the same wiring. A source substrate, 101 is a grid electrode, 102 is an opening through which electrons pass, 103 is an external terminal formed of Dox1, Dox2,... Doxm, 104 is G1, G2,... Gn connected to the grid electrode 101. The other parts having the same functions as those in FIG. 16 or FIG. 18 are denoted by the same reference numerals.
[0168]
The difference between the image display device shown in FIG. 21 and the image display device having the above-described simple matrix arrangement (FIG. 17) is that a grid electrode 101 is provided between the electron source substrate 100 and the face plate 76. The grid electrode 101 is for modulating the electron beam emitted from the surface conduction electron-emitting device, and in order to allow the electron beam to pass through a stripe-shaped electrode provided orthogonal to the ladder-type element row, One circular opening 102 is provided for each element.
[0169]
The shape and installation position of the grid are not limited to those shown in FIG. For example, a large number of passage openings may be provided in the form of a mesh as openings, and a grid may be provided around or near the surface conduction electron-emitting device. The outer container terminal 103 and the outer grid container terminal 104 are electrically connected to a control circuit (not shown).
[0170]
In this image forming apparatus, a modulation signal for one line of an image is simultaneously applied to a grid electrode column in synchronization with sequentially driving (scanning) the element rows one by one. Thus, irradiation of each electron beam to the phosphor can be controlled, and an image can be displayed line by line. According to this, in addition to a display device of a television broadcast, a video conference system, a display device such as a computer, and the like, it can also be used as an image forming device as an optical printer configured using a photosensitive drum or the like.
[0171]
【The invention's effect】
As described in detail above, according to the first aspect of the present invention, a solution containing a metal fine particle material for forming a conductive thin film between a plurality of element electrodes on a substrate is sprayed by a spray head. In the electron source substrate manufacturing apparatus for forming a surface conduction electron-emitting device group using the conductive thin film, an electron emission portion of the surface conduction electron-emitting device is formed by a dot pattern of the solution, and the device electrode is rectangular. An electron source configured by a combination of patterns or rectangular patterns and having a chamfered corner at the rectangular pattern, capable of manufacturing an electron source substrate having a high-quality and highly reliable electron-emitting device that does not cause abnormal discharge. A substrate manufacturing apparatus can be provided.
[0172]
According to the second aspect of the present invention, a solution containing a metal fine particle material for forming a conductive thin film between a plurality of element electrodes on a substrate is sprayed by a spray head, and surface conduction by the conductive thin film is performed. In the electron source substrate manufactured by the electron source substrate manufacturing apparatus forming the group of electron-emitting devices, the conductive thin film is a thin film formed by a dot pattern of the solution obtained by volatilizing a solvent component after applying the solution. ,
An electron source substrate having a high-quality and highly reliable electron-emitting device that does not cause abnormal discharge because the element electrode is formed by a rectangular pattern or a combination of rectangular patterns and the corner of the rectangular pattern is chamfered. Can be obtained.
[0173]
According to the third aspect of the present invention, since the corners of the plurality of device electrodes facing each other are chamfered, an electron source having a high-quality and highly reliable electron-emitting device that does not cause abnormal discharge. A substrate is obtained.
[0174]
According to the fourth aspect of the present invention, the electron source substrate according to the second or third aspect is disposed opposite to the electron source substrate, a phosphor is mounted, and the electron source substrate has substantially the same shape as the electron source substrate. Provided is an image display device having high image quality and high durability by using an electron source substrate having a high quality and highly reliable electron emitting element that does not cause abnormal discharge since it has a face plate of a large size. Can be.
[Brief description of the drawings]
FIGS. 1A and 1B are schematic diagrams showing a configuration of a planar surface conduction electron-emitting device according to an embodiment of the present invention, where FIG. 1A is a plan view and FIG. 1B is a cross-sectional view taken along line BB of FIG. It is.
2A and 2B are schematic diagrams for explaining a method of manufacturing the surface conduction electron-emitting device shown in FIG. 1, wherein FIG. 2A is a diagram in which device electrodes are formed on a substrate, and FIG. (C) is a diagram in which an electron emitting portion is formed on a conductive thin film.
FIG. 3 is a configuration diagram illustrating an example of an apparatus for manufacturing an electron source substrate according to the present invention.
FIG. 4 is a diagram for explaining an example of the configuration of a droplet applying apparatus to which the present invention can be applied.
5 (A) and 5 (B) are schematic views of a main part of a discharge head unit of the droplet applying apparatus of FIG. 4;
FIGS. 6A to 6C are views showing one example of an ejection head used in the apparatus for manufacturing a surface conduction electron-emitting device according to the present invention.
FIGS. 7A to 7D are diagrams for explaining a connection method in the case of forming an electron-emitting device pattern by arranging droplet dots.
FIG. 8 is a diagram for explaining two ITO transparent electrode patterns formed on a substrate.
FIG. 9 is a diagram for explaining a specific example in which dots of droplets are arranged to form an electron-emitting device pattern.
FIG. 10 is a diagram showing a dot pattern previously formed on a substrate.
FIG. 11 is a diagram for explaining a specific example in which droplet dots are arranged in a dot pattern previously formed on a substrate to form an electron-emitting device pattern.
FIG. 12 is a cross-sectional view illustrating a configuration of a planar surface conduction electron-emitting device according to an embodiment of the present invention.
FIGS. 13A and 13B are cross-sectional views for explaining changing a film thickness of an electron-emitting device pattern in an electron-emitting portion and an electrode element portion.
FIGS. 14A and 14B are diagrams showing examples of voltage waveforms in the energization forming process that can be employed in manufacturing the surface conduction electron-emitting device according to the present invention.
FIG. 15A is a diagram for explaining an example in which an electric field concentration occurs at a sharp corner portion of a conventional device electrode, and FIG. 15B is a diagram for explaining an example in which the present invention is applied to eliminate the electric field concentration. FIG.
FIG. 16 is a schematic view showing an example of a matrix-disposed electron source substrate to which the present invention can be applied.
FIG. 17 is a view for explaining an example of a basic configuration of a display panel of an image forming apparatus using a matrix arrangement type electron source substrate to which the present invention can be applied.
FIGS. 18A and 18B are schematic diagrams showing a configuration example of a fluorescent film used in an image forming apparatus to which the present invention can be applied, wherein FIG. 18A is a black stripe type fluorescent film, and FIG. It is a membrane.
FIG. 19 is a block diagram illustrating an example of a drive circuit for performing display on an image forming apparatus in accordance with an NTSC television signal.
FIG. 20 is a schematic diagram showing an example of a ladder-type arrangement type electron source substrate to which the present invention can be applied.
FIG. 21 is a diagram for explaining an example of a basic configuration of a display panel of an image forming apparatus using a ladder-type arrangement type electron source substrate to which the present invention can be applied.
FIG. 22 is a diagram illustrating an example of a conventional electron-emitting device.
[Explanation of symbols]
1 substrate
2,3 element electrode
4 Conductive thin film
5 Electron emission section
10. Electron source board
11 Ejection head unit (ejection head)
12 carriage
13 Substrate holder
14 Substrate
15 Supply tube
16 Signal supply cable
17 Injection head control box
18 X direction scan motor for carriage 12
19 Y direction scan motor of carriage 12
20 computers
21 Control Box
22X1, 22Y1, 22X2, 22Y2 substrate positioning / holding means
30 Discharge head unit
31 Head alignment control mechanism
32 Detection optical system
33 inkjet head
34 Head alignment fine movement mechanism
35 Control computer
36 Image recognition mechanism
37 XY scanning mechanism
38 Position detection mechanism
39 Position correction control mechanism
40 Inkjet head drive / control mechanism
41 Optical axis
42 droplets
43 Droplet landing position
44 dots
50 Injection head (inkjet head)
51 Heating element substrate
52 lid substrate
53 Silicon substrate used for forming heating element substrate 51
54 individual electrodes
55 common electrode
56 Heating element
57 Solution inlet
58 nozzles
59 Groove
60 recess area
61 X direction wiring
62 Y direction wiring
63 surface conduction electron-emitting device
64 connections
71 Rear plate to which electron source substrate 10 is fixed
72 Support frame
73 glass substrate
74 fluorescent film
75 metal back
76 face plate
78 envelope
81 black conductive material
82 phosphor
91 Image display panel
92 scanning circuit
93 Control circuit
94 shift register
95 line memory
96 Synchronous signal separation circuit
97 Modulation signal generator
98 Common wiring composed of Dx1 to Dx10 connected to the electron-emitting device 63
100 Electron source substrate with common wiring between each element row
101 grid electrode
102 Aperture for electron passage
103 Dox1, Dox2 ... Doxm outer terminal
104 Out-of-container terminals composed of G1, G2,... Gn connected to the grid electrode 101
Vx, Va DC voltage source

Claims (4)

An electron source for spraying a solution containing a metal particulate material for forming a conductive thin film between a plurality of device electrodes on a substrate by a spray head to form a surface conduction electron-emitting device group using the conductive thin film; In substrate manufacturing equipment,
An electron emission portion of the surface conduction electron-emitting device is formed by a dot pattern of the solution,
An electron source substrate manufacturing apparatus, wherein the element electrode is formed of a rectangular pattern or a combination of rectangular patterns, and a corner of the rectangular pattern is chamfered. An electron source substrate that forms a group of surface conduction electron-emitting devices using a conductive thin film by spraying a solution containing a metal fine particle material for forming a conductive thin film between a plurality of device electrodes on a substrate by a spray head. In the electron source substrate manufactured by the manufacturing apparatus,
The conductive thin film is a thin film formed by a dot pattern of the solution obtained by volatilizing a solvent component after applying the solution,
An electron source substrate, wherein the element electrode is formed by a rectangular pattern or a combination of rectangular patterns, and a corner of the rectangular pattern is chamfered. 3. The electron source substrate according to claim 2, wherein corner portions of the plurality of device electrodes on opposite sides are chamfered. 4. An electron source substrate according to claim 2 or 3, and a face plate disposed opposite to the electron source substrate, mounted with a phosphor, and having substantially the same shape and size as the electron source substrate. Image display device.

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