JP3830459B2 - Electron source substrate manufacturing apparatus, electron source substrate and image display device - Google Patents

Description

【００６１】
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。
【００６２】
【表２】

【００６３】
【表３】

【００６４】
【表４】

【００６５】
【表５】

【００６６】
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。
【００６７】
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。
【００６８】
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。
【００６９】
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。
【００７０】
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。
【００７１】
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。
【００７２】
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。
【００７３】
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。
【００７４】
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。
【００７５】
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。
【００７６】
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。
【００７７】
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。
【００７８】
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。
【００７９】
【表６】

【００８０】
【表７】

【００８１】
【表８】

【００８２】
【表９】

【００８３】
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。
【００８４】
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。
【００８５】
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。
【００８６】
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。
【００８７】
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。
【００８８】
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。
【００８９】
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。
【００９０】
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。
【００９１】
次に本発明のさらに他の特徴について説明する。本発明の電子放出素子基板は、金属微粒子を溶液中に分散させてなる微粒子含有溶液をインクジェットの原理で空中を飛翔させ，基板上に付与して製作されるものであるが、高精度かつ高品位な電子放出素子基板を形成するためには、その溶液を噴射、付与して、溶液のドットパターン形成を行う際の基板の表面粗さ金属微粒子の大きさを最適化しておく必要がある。
【００９２】
たとえば、基板の表面粗さというのは、その表面の凹凸であるが、図７のように、この凹凸からはみ出すような大きさの粒子が、基板の表面に付着すると、良好なドットパターン、ひいては良好な電子放出素子が得られないであろう。一方で、図８のように、この凹凸以下の大きさの粒子であれば、良好なドットパターンが得られるであろう。
【００９３】
本発明ではこの点に鑑み、あらかじめ表面粗さのわかっている基板上に、サイズの異なる金属微粒子を含有させた溶液によって、ドットパターンを形成し、その形成されたパターンの良否を評価した。
【００９４】
実験は、パイレックス（登録商標）ガラスを研摩し、その表面粗さが０．０１ｓ〜０．０２ｓとなるようにし、その研摩された基板上に前述のパラジウム微粒子含有溶液（ここでは、微粒子径が０．０００５μｍ〜０．２μｍのものを使用）を前述のＨ４噴射ヘッド（ノズル径Φ１０μｍ）と組み合わせて噴射させ、ドットをつなぎあわせたパターンを形成し、そのパターンの滑らかさを顕微鏡下で観察し、官能評価し、良〜可〜不良（○〜△〜×）を判断した。
【００９５】
実験条件の詳細を以下に示す。パターンは縦方向に１列で、約Φ１０μｍのドットを約６μｍピッチで約１００個打ち込んだものである。使用した噴射ヘッドはＨ４噴射ヘッドであり、ノズル（吐出口）の数が６４個で、その配列密度が１００ｄｐｉのものである。噴射ヘッドと基板は相対運動（ここでは、基板固定、噴射ヘッドをキャリッジ走査）を行い、その制御をμオーダーで制御し、また噴射のタイミングをコントロールし、上記のように約６μｍピッチによるドット付着を行った。
【００９６】
液滴噴射の駆動電圧はピエゾ素子への入力電圧を１６Ｖとし、また駆動周波数は１０ｋＨｚとした。噴射滴の体積はいつもほぼ１．５ｐｌである。また滴飛翔時の滴の形状を、パターン形成と同じ条件で別途噴射、観察し、その形状が、基板面に付着する直前（今本発明例では３ｍｍ）にほぼ丸い滴になるように駆動波形を制御して噴射させた。なお完全に丸い球状が得られず、飛翔方向に伸びた柱状であっても、液柱の長さｌは駆動波形を制御するだけで容易にその直径の３倍以内の長さになる（ｌ≦３ｄ）ようにできた。またその際、飛翔滴後方に複数の微小な滴を伴うことのない駆動条件（駆動波形）を選んだ。
【００９７】
前述のようにパラジウム微粒子含有溶液は、微粒子径が０．０００５μｍ〜０．２μｍまで異なるものをそれぞれ準備して使用した（溶液Ｎｏは共通である）が、微粒子径が０．０２μｍ以上の場合には、ノズル目詰まりが発生し始めるので、形成したパターンのうち、目詰まりが生じなくて、良好にパターン形成されたもののみを選別して評価を行った。下記表１０に結果を示す。
【００９８】
【表１０】

【００９９】
以上の結果より、溶液に含有される金属微粒子は、基板のパターンが形成される面の表面粗さ以下の大きさとすることにより、滑らかな良好なパターンが形成できることがわかる。一方で、金属微粒子の大きさをそれより大きくすると、パターン形状の滑らかさが損なわれることがわかる。
【０１００】
次に本発明のさらに他の特徴について説明する。前述のように本発明は、金属微粒子を溶液中に分散させてなる微粒子含有溶液をインクジェットの原理で空中を飛翔させ、基板上に付与してパターンを形成し、電子放出素子を製作するものであるが、溶液噴射、付与後の液滴あるいは溶液によって形成されるドットパターン中の揮発成分が揮発後の固形分が残留することによってできる電子放出部のパターンの厚さが、高品位な電子放出素子を得るためには重要となる。例えば電子放出素子を形成する基板は、ある表面粗さを持っているが、良好な電子放出素子を得るためには、パターンの厚さとこの表面粗さ、すなわち表面の凹凸との関係を適切に選ぶ必要がある。以下に検討結果を示す。
【０１０１】
実験は、その表面粗さが異なるパイレックス（登録商標）ガラス基板を用意し、そこに１対の素子電極を形成したものに、パラジウム微粒子含有溶液を前述のＨ４噴射ヘッド（ノズル径Φ１０μｍ）と組み合わせて噴射させ、ドットをつなぎあわせたパターンを形成し、それを後述のフォーミング処理を行って素子を作成し、実際に良好に機能するかどうか（良好な電子放出が得られる…○，電子放出が得られない…×）を評価した。なお、パターン膜厚を変えるために、溶液は、前述のＮｏ．４の溶液（パラジウム微粒子径Ｄｐ＝０．００２μｍ）を純水により２〜５０倍に希薄して使用した。その結果，噴射，付与によりパターンが形成され、乾燥して固形分が残留した後のパターン膜厚の異なる電子放出素子を形成することができた。
【０１０２】
実験条件の詳細を以下に示す。パターンは縦方向に１列で、約Φ１０μｍのドットを約６μｍピッチで４個打ち込んだものである。噴射ヘッドと基板は相対運動（ここでは、基板固定、噴射ヘッドをキャリッジ走査）を行い、その制御をμオーダーで制御し、また噴射のタイミングをコントロールし、上記のように約６μｍピッチによるドット付着を行った。
【０１０３】
液滴噴射の駆動電圧はピエゾ素子への入力電圧を１６Ｖとし、また駆動周波数は１０ｋＨｚとした。噴射滴の体積はいつもほぼ１．５ｐｌである。また滴飛翔時の滴の形状を、パターン形成と同じ条件で別途噴射、観察し、その形状が、基板面に付着する直前（今本発明例では３ｍｍ）にほぼ丸い滴になるように駆動波形を制御して噴射させた。下記表１１に結果を示す。
【０１０４】
【表１１】

【０１０５】
以上の結果より、本発明の原理によって形成される電子放出素子は、その電子放出部の前記パターンの厚さを基板の表面粗さ以上の厚さとなるようにすることにより、良好な電子放出素子が得られることがわかる。
【０１０６】
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）。
【０１０７】
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。
【０１０８】
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。
【０１０９】
図９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９（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９（Ｂ））とがある。まずパルス波高値が一定電圧とした場合（図９（Ａ））について説明する。
【０１１０】
図９（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。
【０１１１】
図９（Ｂ）におけるＴ１およびＴ２は、図９（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。
【０１１２】
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。
【０１１３】
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。
【０１１４】
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。
【０１１５】
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。
【０１１６】
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。
【０１１７】
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。
【０１１８】
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。
【０１１９】
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。
【０１２０】
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。
【０１２１】
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。
【０１２２】
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。
【０１２３】
図１０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）。
【０１２４】
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。
【０１２５】
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。
【０１２６】
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。
【０１２７】
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１１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。
【０１２８】
また、図１１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。
【０１２９】
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。
【０１３０】
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。
【０１３１】
図１２は、図１１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１２（Ａ）に、ブラックマトリックスタイプの蛍光膜を図１２（Ｂ）に示すものである。図１２において、７４は蛍光膜、８１は黒色導電材、８２は蛍光体である。
【０１３２】
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。
【０１３３】
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。
【０１３４】
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。
【０１３５】
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１２）の内面側には通常、メタルバック７５が設けられる。
【０１３６】
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。
【０１３７】
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。
【０１３８】
図１１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。
【０１３９】
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。
【０１４０】
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１３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１３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。
【０１４１】
以下、図１３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。
【０１４２】
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。
【０１４３】
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。
【０１４４】
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。
【０１４５】
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。
【０１４６】
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。
【０１４７】
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。
【０１４８】
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。
【０１４９】
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。
【０１５０】
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。
【０１５１】
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。
【０１５２】
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。
【０１５３】
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。
【０１５４】
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。
【０１５５】
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。
【０１５６】
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。
【０１５７】
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。
【０１５８】
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。
【０１５９】
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１４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）。
【０１６０】
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。
【０１６１】
図１５は、図１４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１１または図１４と同様の機能を有する部分には、同一符号を付してある。
【０１６２】
図１５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１１）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。
【０１６３】
なおグリッドの形状や設置位置は図１４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。
【０１６４】
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。
【０１６５】
【発明の効果】
以上、詳述したように、基板上の一対の素子電極間に導電性薄膜を形成するための材料を含有する溶液の液滴を吐出口径Φ２５μｍ以下の液滴噴射ヘッドにより噴射付与し、付与後の液滴のドットパターン中の揮発成分を揮発させ、固形分を前記基板上に残留させることによって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り、前記金属微粒子は前記ドットパターンを形成する面の表面粗さ以下の大きさであるとともに、前記金属微粒子の大きさをＤｐ、前記吐出口径をＤｏとするとき、０．０００１≦Ｄｐ／Ｄｏ≦０．０１としたので、溶液の噴射時に目詰まりが起きない長期使用に対して安定して使用できる新規な電子源基板製造装置を提供することができる。
【０１６６】
また、前記ドットパターンの厚さを前記表面粗さ以上の厚さとなるように噴射制御するようにしたので、形成される電子放出素子は高品位となり、良好な電子放出が行える電子源基板を製作できる。
【０１６７】
請求項２に記載の発明によれば、基板上の一対の素子電極間に導電性薄膜を形成するための材料を含有する溶液を吐出口径Φ２５μｍ以下の溶液噴射ヘッドにより噴射付与し、付与後の溶液によるドットパターン中の揮発成分を揮発させ、固形分を前記基板上に残留させることによって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り、前記金属微粒子は前記ドットパターンを形成する面の表面粗さ以下の大きさであるとともに、前記金属微粒子の大きさをＤｐ、前記吐出口径をＤｏとするとき、０．０００１≦Ｄｐ／Ｄｏ≦０．０１としたので，溶液の噴射時に目詰まりが起きない長期使用に対して安定して使用できる新規な電子源基板製造装置を提供することができる。
【０１６８】
また、前記ドットパターンの厚さを前記表面粗さ以上の厚さとなるように噴射制御するようにしたので，形成される電子放出素子は高品位となり，良好な電子放出が行える電子源基板を製造できる。
【０１６９】
請求項３に記載の発明によれば、このような電子源基板製造装置に使用する溶液において、該溶液に含有される前記導電性薄膜を形成するための金属微粒子を含有する溶液は、前記金属微粒子の大きさをＤｐ、前記吐出口径をＤｏとするとき、０．０００１≦Ｄｐ／Ｄｏ≦０．０１とするとともに、前記金属微粒子は、前記基板の前記ドットパターンが形成される面の表面粗さ以下の大きさであるようにしたので、溶液の噴射時に目詰まりが起きないようになり、高品位な電子源基板を安定して製造できる。
【０１７０】
請求項４に記載の発明によれば、このような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、基板上の複数対の各素子電極間に導電性薄膜を形成するための材料として金属微粒子を含有する溶液を吐出口径Φ２５μｍ以下の液滴噴射ヘッドにより噴射付与し、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、前記導電性薄膜は前記溶液付与後に溶媒成分を揮発させてなるドットパターンの薄膜であるとともに、該ドットパターンの一部に亀裂を発生させた金属微粒子を含有する薄膜であって、前記金属微粒子は前記ドットパターンの薄膜を形成する面の表面粗さ以下の大きさであるとともに、前記金属微粒子の大きさをＤｐ、前記吐出口径をＤｏとするとき、０．０００１≦Ｄｐ／Ｄｏ≦０．０１
としたので、溶液の噴射時に目詰まりが起きない長期使用に対して安定して使用できる新規な電子源基板製造装置を提供することができる。
【０１７１】
また、前記薄膜の厚さを前記表面粗さ以上の厚さとしたので、形成される電子放出素子は高品位となり、良好な電子放出が行える電子源基板とすることができる。
【０１７２】
請求項５に記載の発明によれば、高品位で信頼性の高い表面伝導型電子放出素子のパターンを有し、電子放出素子特性も優れた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得ることができる。
【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】基板の表面粗さより大である金属微粒子を含有した溶液によってドットパターンを形成した場合の、金属微粒子と表面粗さの関係を模式的に示した図である。
【図８】基板の表面粗さ以下の大きさの金属微粒子を含有した溶液によってドットパターンを形成した場合の、金属微粒子と表面粗さの関係を模式的に示した図である。
【図９】（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１０】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１１】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１２】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１３】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１４】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１５】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１６】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]
BACKGROUND OF THE INVENTION
The present invention relates to an electron source substrate manufacturing apparatus for manufacturing an electron source substrate using a surface conduction electron-emitting device, a solution used in the electron source substrate manufacturing apparatus, and an electron source substrate prepared by the electron source substrate manufacturing apparatus. And an image display device using the electron source substrate.
[0002]
[Prior art]
Conventionally, two types of electron-emitting devices are known: a thermionic source and a cold cathode electron source. Cold cathode electron sources include 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 electron emission element, and the like.
Examples of FE types include “WP Dyke & W. W. Dolan,“ Field mission ”, Advance in Electron Physics, 8 89 (1956)” or “C. molybdenium “J. Appl. Phys., 475248 (1976)” and the like are known.
[0003]
As an example of the MIM type, “CA Mead,“ The Tunnel-emission amplifier ”, J. Appl. Phys., 32 646 (1961)” is known.
[0004]
Examples of the surface conduction electron-emitting device type include “MI Elinson, Radio Eng. Electron Phys., 1290 (1965)”. The surface conduction electron-emitting device utilizes a phenomenon in which electron emission occurs when a current flows through a small-area thin film formed on a substrate in parallel to the film surface.
As this surface conduction electron-emitting device, SnOl by Elinson et al. ₂ Thin film, Au thin film (“G. Dittmer:“ Thin Solid Films ”, 9 317 (1972))), In ₂ O ₃ / SnO ₂ By thin film ("M. Hartwell and C.G. Fonstad:" IEEEETrans. ED Conf. ", 519 (1975))), by carbon thin film (" Hiroshi Araki et al .: Vacuum, Vol. 26, No. 1, 22 (1983) ") has been reported.
[0005]
As a typical device configuration of these surface conduction electron-emitting devices, the above-described M.I. FIG. 16 shows a Hartwell device configuration. In FIG. 16, a is a substrate, b and c are element electrodes, d is a conductive thin film, and the conductive thin film d is formed of a metal oxide thin film formed by sputtering in an H-shaped pattern, which will be described later. The electron emission portion e is formed by an energization process called energization forming. In the figure, the distance L1 between the element electrodes b and c 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, it is common to form the electron-emitting portion e by performing an energization process called energization forming on the conductive thin film d in advance before electron emission. . In the energization forming, a DC voltage or a very slow rising voltage, for example, about 1 V / min is applied to both ends of the conductive thin film d, and the conductive thin film d is locally broken, deformed or altered, and electrically The formation of the electron emission portion e in a high resistance state.
[0007]
In the electron emission portion e, a crack is generated in a part of the conductive thin film d, and electron emission is performed from the vicinity of the crack. The surface conduction electron-emitting device subjected to the energization forming process emits electrons from the electron-emitting portion e by applying a voltage to the conductive thin film d and passing a current through the device.
[0008]
Since the surface conduction electron-emitting device as described above has a simple structure and is easy to manufacture, there is an advantage that a large number of devices can be formed over a large area. Therefore, applied researches on charged beam sources, display devices, etc. that take advantage of this feature have been made.
[0009]
As an example in which a large number of surface-conduction electron-emitting devices are arrayed, as will be described later, surface-conduction electron-emitting devices are arrayed in parallel, called a trapezoidal arrangement, and both ends of each element are wired (also called common wiring) ), An electron source in which a plurality of connected lines are arranged (for example, Japanese Patent Laid-Open Nos. 64-31332, 1-283749, and 2-257552).
[0010]
In particular, in an image forming apparatus such as a display device, in recent years, flat panel display devices using liquid crystals have been used in place of CRTs, but problems such as having a backlight because they are not self-luminous. Therefore, development of a self-luminous display device has been desired. Examples of the self-luminous display device include an image forming apparatus that is a display device in which an electron source in which a large number of surface-conduction emission elements are arranged and a phosphor that emits visible light by electrons emitted from the electron source. (For example, US Pat. No. 5,066,883).
[0011]
However, the manufacturing method according to the above-described conventional example of the surface conduction electron-emitting device uses a lot of vacuum film formation and the photolithography etching method in the semiconductor process, and there are many steps to form the device over a large area. There is a disadvantage that the production cost of the electron source substrate is high.
[0012]
In order to solve the above-mentioned problems, the present inventor, in forming the conductive thin film of the element portion of the surface conduction electron-emitting device as described above, U.S. Pat. Nos. 3,060,429, 3,298,030, 3,596,275, By means of ink jet droplet applying means such as known as 3416153, 3747120, 5729257, etc., the above-mentioned conductive property can be stably produced with good yield and low cost regardless of the vacuum film forming method and photolithography etching method. I thought that a thin film could be formed. And the result examined extensively about the specific 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 so-called ink is ejected toward paper and recording is performed, there are still many unresolved elements for stably flying a solution containing an element that becomes a conductive thin film and applying it onto a substrate. Exists. For example, such an element is generally a metal element, and there are still many unknown techniques for stably jetting a solution containing metal fine particles over a long period of time. In particular, the problem of clogging must be solved in order to make the jet performance over a long period constant.
[0015]
Conventionally, in the field of ink jet recording using a recording liquid in which a water-soluble dye is dissolved, the ejection port (nozzle) of the head used is conventionally Φ33 μm to Φ34 μm (cross-sectional area 900 μm). ² Φ50μm to Φ51μm (cross-sectional area 2000μm) ² However, since the dye is dissolved in the liquid medium, the problem of anti-clogging has been addressed. However, a solution containing fine metal particles as in the present invention is, for example, Φ25 μm or less (cross-sectional area 500 μm ² No technology has been established for stable ejection over a long period of time from an unprecedented fine discharge port.
[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, and the object of the invention of claim 1 is high quality and high accuracy. It is another object of the present invention to provide an electron source substrate manufacturing apparatus capable of stably manufacturing an electron source substrate having an electron-emitting device having high reliability without clogging during injection.
[0017]
The object of the invention of claim 2 is the same as that of the invention of claim 1. An object of the invention of claim 3 is to provide a solution for forming a conductive thin film that can use the manufacturing apparatus having such a novel configuration with high reliability. Another object of the present invention is to provide an electron source substrate having a high-quality electron-emitting device manufactured by the manufacturing apparatus having such a novel configuration. An object of the invention of claim 5 is to provide an image display apparatus using an electron source substrate having a high-quality electron-emitting device.
[0018]
[Means for Solving the Problems]
Therefore, the invention according to claim 1 is provided on the substrate. A pair of A droplet of a solution containing a material for forming a conductive thin film between element electrodes is ejected and applied by a droplet ejection head having a discharge port diameter of Φ25 μm or less, and the droplet after application Dot pattern A solution containing a material for forming the conductive thin film in an electron source substrate manufacturing apparatus for forming a surface conduction electron-emitting device group by volatilizing a volatile component therein and leaving a solid content on the substrate Is a solution in which metal fine particles are dispersed in a liquid, and the metal fine particles are Dot pattern When the size of the metal fine particles is Dp and the discharge port diameter is Do, 0.0001 ≦ Dp / Do ≦ 0.01, Dot pattern The injection control is performed so that the thickness of the film becomes equal to or greater than the surface roughness.
[0019]
The invention according to claim 2 is provided on a substrate. A pair of A solution containing a material for forming a conductive thin film between element electrodes is sprayed and applied by a solution jet head having a discharge port diameter of Φ25 μm or less, and the solution after the application Dot pattern by A solution containing a material for forming the conductive thin film in an electron source substrate manufacturing apparatus for forming a surface conduction electron-emitting device group by volatilizing a volatile component therein and leaving a solid content on the substrate Is a solution in which metal fine particles are dispersed in a liquid, and the metal fine particles are Dot pattern When the size of the metal fine particles is Dp and the discharge port diameter is Do, 0.0001 ≦ Dp / Do ≦ 0.01, Dot pattern The injection control is performed so that the thickness of the film becomes equal to or greater than the surface roughness.
[0020]
The invention according to claim 3 is provided on a substrate. A pair of A solution containing metal fine particles as a material for forming a conductive thin film between element electrodes is sprayed and applied by a droplet jet head having a discharge port diameter of Φ25 μm or less, and the solution after the application Dot pattern by In the metal fine particle-containing solution used for the electron source substrate manufacturing apparatus for forming the surface conduction electron-emitting device group by volatilizing the volatile components therein and leaving the solid content on the substrate, the size of the metal fine particles is determined. Dp, when the discharge port diameter is Do, 0.0001 ≦ Dp / Do ≦ 0.01, and the metal fine particles are formed on the substrate. Dot pattern The surface is formed with a surface roughness less than the surface roughness.
[0021]
The invention according to claim 4 is provided on a substrate. A pair of Electron source substrate manufacturing apparatus for forming a surface conduction electron-emitting device group by spraying and applying a solution containing metal fine particles as a material for forming a conductive thin film between device electrodes by a droplet jet head having a discharge port diameter of Φ25 μm or less In the electron source substrate manufactured by the method, the conductive thin film is formed by volatilizing a solvent component after applying the solution. Dot pattern A thin film, A crack occurred in a part of the dot pattern A thin film containing fine metal particles, wherein the fine metal particles are Dot pattern When the size of the surface of the surface on which the thin film is formed is equal to or less than the surface roughness, the size of the metal fine particles is Dp, and the discharge port diameter is Do, 0.0001 ≦ Dp / Do ≦ 0.01, Dot pattern The thickness of the thin film is equal to or greater than the surface roughness.
[0022]
According to a fifth aspect of the present invention, there is provided the electron source substrate according to the fourth aspect of the present invention, a face that is disposed opposite to the electron source substrate, has a phosphor, and has substantially the same shape and size as the electron source substrate. And a plate.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a schematic view showing an example of an electron source substrate that constitutes 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 line BB in FIG. 1A, in which 1 is a substrate, 2 and 3 are element electrodes, 4 is a conductive thin film, and 5 is an electron emission portion.
[0024]
The basic configuration of the surface conduction electron-emitting device of the present invention is a planar type, and here, the configuration of one planar surface conduction electron-emitting device is schematically shown in a simplified manner. As will be described later, such a planar surface conduction electron-emitting device is configured as an element group in a matrix arrangement.
[0025]
As the substrate 1, quartz glass, glass with a reduced content of impurities such as Na, blue plate glass, SiO 2 ₂ It is possible to use a glass substrate having a surface deposited with a ceramic substrate such as alumina.
[0026]
As a material of the device electrodes 2 and 3, a general conductive material can be used. For example, a metal or alloy such as Ni, Cr, Au, Mo, W, Pt, Ti, Al, Cu, Pd, Pd, As, Ag, Au, RuO ₂ , Printed conductor composed of metal such as Pd-Ag or metal oxide and glass, In ₂ O ₃ -SnO ₂ A transparent conductor such as, a semiconductor material such as polysilicon, and the like are appropriately selected.
[0027]
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 characteristic of the electrodes, and the film thickness d of the device electrodes 2 and 3 is 100 μm to 1 μm. It is a range. Note that the present invention is not limited to the configuration shown in FIG. 1, and a configuration in which the conductive thin film 4 and the electrodes of the element electrodes 2 and 3 are sequentially formed on the substrate 1 may be employed.
[0028]
FIG. 2 is a diagram for explaining a method of manufacturing the planar surface conduction electron-emitting device shown in FIG. 1. FIG. 2 (A) is a diagram in which device electrodes 2 and 3 are formed on the substrate 1. FIG. 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.
[0029]
The conductive thin film 4 is particularly preferably a fine particle film composed of fine particles in order to obtain good electron emission characteristics, and the film thickness is step coverage to the device electrodes 2 and 3 and the resistance between the device electrodes 2 and 3. Although it is appropriately set depending on the value, energization forming conditions described later, etc., it is preferably several to thousands, and particularly preferably 10 to 500. 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 of t, a width of w, and a length of 1 is R = Rs (1 / w), and the resistivity of the thin film material is ρ. Rs = ρ / t.
[0030]
Here, the energization process is described as an example of the forming process. However, the forming process is not limited to this, and any method can be used as long as the film is cracked to form a high resistance state. May be.
[0031]
As a material constituting the conductive thin film 4, metals such as Pd, Pt, Ru, Ag, Zn, Sn, W, and Pb can perform good electron emission as the surface conduction electron-emitting device of the present invention. As a material. However, as described later, it is necessary to consider compatibility with the droplet ejecting head used in the manufacturing apparatus of the present invention, and not all of these materials can be suitably used.
[0032]
The fine particle film described here is a film in which a plurality of fine particles are aggregated, and the fine structure is not only in a state where the fine particles are individually dispersed and arranged, but also in a state where the fine particles are adjacent to each other or overlap (some fine particles are aggregated And the case where an island is formed as a whole). The particle diameter of the fine particles is several to 1 μm, preferably 10 to 200 μm.
[0033]
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 below. FIG. 3 is a view showing an example of an electron source substrate manufacturing apparatus according to the present invention, in which 11 is an ejection head unit (jet head), 12 is a carriage, 13 is a substrate holder, and 14 is a planar surface conduction device. 15 is a substrate for forming a group of electron-emitting devices, 15 is a solution supply tube 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 for the carriage 12, and 19 is A Y-direction scan motor of the carriage 12, 20 is a computer, 21 is a control box, 22X1, 22Y1, 22X2, and 22Y2 are substrate positioning / holding means.
[0034]
The configuration shown in FIG. 3 shows an example in which the ejection head 11 moves by carriage scanning on the front surface of the substrate 14 placed on the substrate holder 13 and ejects a solution containing a conductive thin film material. The ejection head 11 may be of any mechanism as long as it can quantitatively discharge arbitrary droplets, and in particular, an inkjet mechanism that can form droplets of several tens to several picoliters or a smaller volume of droplets is desirable. . The ink jet method may be any of a piezo jet method using a piezoelectric element, a bubble jet (registered trademark) method that generates bubbles using the thermal energy of a heater, or a charge control method (continuous flow method). .
[0035]
FIG. 4 is a schematic diagram for explaining an example of a configuration of a droplet applying apparatus to which the method of manufacturing an electron source substrate of the present invention can be applied. FIG. 5 is a diagram of an ejection head unit of the droplet applying apparatus of FIG. It is a principal part schematic block diagram. The configuration of FIG. 4 is different from the configuration of FIG. 3 in that the electron-emitting device group is formed on the substrate by moving the substrate side.
[0036]
4 and 5, reference numerals 2 and 3 are element electrodes, 14 is a substrate, 30 is an ejection head unit (corresponding to the ejection head 11 in FIG. 3), 31 is a head alignment control mechanism, 32 is a detection optical system, and 33 is an inkjet. Head, 34 is a head alignment fine movement mechanism, 35 is a control computer, 36 is an image identification mechanism, 37 is an XY direction 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.
[0037]
As in the case of FIG. 3, the droplet applying device (inkjet head 33) of the ejection head unit 30 is preferably an inkjet mechanism, a piezojet method using a piezoelectric element, and bubbles using the thermal energy of a heater. Any method such as a bubble jet (registered trademark) system for generating the charge or a charge control system (continuous flow system) may be used.
[0038]
The configuration of the apparatus for moving the substrate 14 side as described above will be described below. First, in FIG. 4, the substrate 14 is placed on the XY direction scanning mechanism 37. The surface conduction electron-emitting device on the substrate 14 has the same structure as that shown in FIG. 1, and the single device is the same as that shown in FIG. 1, and the substrate 1, the device electrodes 2 and 3, and the conductive thin film (fine particle film). It is made up of four.
[0039]
An ejection head unit 30 for applying droplets is positioned above the substrate 14. In the present embodiment, the discharge head unit 30 is fixed, and the substrate 14 is moved to an arbitrary position by the XY direction scanning mechanism 37, whereby the relative movement between the discharge head unit 30 and the substrate 14 is realized.
[0040]
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, the optical axis 41 and the focal position of the detection optical system 32, and the droplet 42 by the inkjet head 33. The landing positions 43 are arranged so as to coincide with each other.
[0041]
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.
[0042]
Returning again to FIG. The image identification mechanism 36 identifies the image information captured by the previous detection optical system 32, and has a function of binarizing the contrast of the image and calculating the centroid position of the 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 giving position information on the substrate 14 to the image information obtained thereby is a position detection mechanism 38. For this purpose, a length measuring device such as a linear encoder provided in the XY direction scanning mechanism 37 can be used.
[0043]
The position correction control mechanism 39 corrects the position based on the image information and the position information on the substrate 14, and this mechanism corrects the movement of the XY direction scanning mechanism 37. Further, the inkjet head 33 is driven by the inkjet head drive / control mechanism 40, and droplets are applied onto the substrate 14. Each control mechanism described so far is centrally controlled by the control computer 35.
[0044]
In the above description, the ejection head unit 30 is fixed, and the substrate 14 is moved to an arbitrary position by the XY direction scanning mechanism 37 to realize relative movement between the ejection head unit 30 and the substrate 14. As shown in FIG. 3, it goes without saying that the substrate 14 may be fixed and the ejection head unit 30 may scan in the XY directions.
[0045]
In particular, when 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 X, the ejection head unit 30 is orthogonal to each other. It is preferable that the scanning is performed in two directions Y, and the application of the solution droplets is sequentially performed in the two orthogonal directions.
[0046]
When the substrate size is about 200 mm × 200 mm or less, the discharge head unit for applying droplets is a large array multi-nozzle type that can cover a range of 200 mm, and the relative movement of the discharge head unit and the substrate is orthogonal to two directions ( It is possible to make relative movement only in one direction (for example, only in the X direction) without performing in the X direction and the Y direction, and the mass productivity can be improved, but the substrate size is 200 mm × 200 mm or more. Therefore, it is difficult to realize a large-array multi-nozzle type discharge head unit capable of covering such a range of 200 mm in terms of technology / cost, and the discharge head unit 30 is orthogonal to each other as in the present invention. , Y is scanned in two directions, and liquid droplets are sequentially applied in two orthogonal directions. It is better to have a configuration that does this.
[0047]
As the material of the droplets 42, an aqueous solution, an organic solvent, or the like containing the element or compound that becomes the conductive thin film described above can be used. For example, when the element or compound used as the conductive thin film is palladium, examples thereof include palladium acetate-ethanolamine complex (PA-ME), palladium acetate-diethanol complex (PA-DE), palladium acetate-triethanolamine. An aqueous solution containing an ethanolamine complex such as a complex (PA-TE), palladium acetate-butylethanolamine complex (PA-BE), palladium acetate-dimethylethanolamine complex (PA-DME), or palladium-glycine complex ( Pd-Gly), palladium-β-alanine complex (Pd-β-Ala), an aqueous solution containing an amine acid complex such as palladium-DL-alanine complex (Pd-DL-Ala), and further palladium acetate-bis- Examples thereof include a butyl acetate solution of a di-propylamine complex.
[0048]
More specifically, for example, in the case of a palladium acetate-triethanolamine aqueous solution, it is produced as follows. That is, 50 g of palladium acetate is suspended in 500 cc of isopropyl alcohol, 100 g of triethanolamine is further added, and the mixture is stirred at 35 ° C. for 12 hours.
[0049]
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 palladium acetate-triethanolamine thus obtained can be dissolved in 190 g of pure water to obtain a jetting solution.
[0050]
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 into a jetting solution.
[0051]
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 compound that becomes a conductive thin film in the air on the principle of ink jet and applying it 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 stably maintain a certain level of performance.
[0052]
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, the metal fine particles are present like abrasive grains dispersed in the solution, and when this solution is used in large quantities, there is a problem that the passage of the solution of the jet head is damaged or worn. Among the passages, scratches and abrasion of the discharge port (nozzle) are particularly problematic because they affect the droplet ejection performance of the solution.
[0053]
By the way, the scratches and wear are caused when two objects collide with each other or rub against each other. Therefore, it is considered that they can be solved by appropriately selecting the hardness of each other. In addition, it is true that scratches affect the droplet jetting performance of the jet head, but how much the scratches are affected is considered to be determined by the size of the scratch and the size of the solution path. For example, even if a water discharge hose having an inner diameter of Φ15 mm to Φ20 mm has scratches on the order of nanometers, the water discharge flow rate cannot be greatly affected.
[0054]
In the present invention, these points are taken into consideration and 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 an ejection head having a multi-nozzle plate attached to the surface of the rectangular nozzle portion 58 with an ejection head as shown in FIG. It was investigated whether or not the nozzle hole) was flawed, and whether or not the element shape to be formed (the shape of the dot pattern was good) and the element performance were deteriorated due to the deterioration of the solution droplet discharge performance. Multi-nozzle plates were prepared with different materials and nozzle diameters (here rounded). The device performance was examined after performing a forming process described later.
[0055]
The ejecting head used is a thermal ink jet system that uses thermal energy. As described above, a nozzle plate is mounted on the ejecting head of FIG. 6 (nozzle plate is not shown). For simplicity, only four outlets are shown for ease of explanation. Actually, the number of discharge ports is 64, and the arrangement density is 400 dpi.
[0056]
The size of the heating element was 22 μm × 90 μm, the resistance value 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. The injection was performed continuously for 100 hours, and the discharge port portion after injection was observed with an SEM to examine the presence or absence of scratches. The discharge port diameters of Φ25 μm (H1), Φ16 μm (H2), and Φ10 μm (H3) were prepared. As a comparative reference example, one having a discharge port diameter of Φ36 μm (reference head) was also prepared.
[0057]
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 value was 120Ω, 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 speed of the droplet during ejection was about 8 m / s in any ejection head.
[0058]
The nozzle plate was made of Ni and austenitic stainless steel SUS304. A Ni nozzle made of a multi-nozzle plate by an electroforming method, and a nozzle made of SUS304 made of stainless steel foil was drilled with a nozzle hole by electric discharge machining. When the hardness was measured with a Vickers hardness meter, the Vickers hardness Hv was 58 to 63 in the case of Ni material, and the Vickers hardness Hv was 170 to 190 in the case of SUS304 material.
[0059]
The liquids used were S1 to S7 shown in Table 1 below, and the element names of the contained metal particles and the Vickers hardness Hv in the bulk state were shown, respectively. In addition, this Vickers hardness Hv published the value of the metal data book (edited by the Japan Institute of Metals, revised 3rd edition, published by Maruzen). The metal fine particle content in each solution was about 7%, and the fine particle diameter was 150 to 200 mm.
[0060]
[Table 1]

[0061]
The results of evaluation using these sample solutions and the ejection head are shown in Tables 2 to 5 below. In the table, scratches ○ indicate that no conspicuous scratches could be confirmed after 100 hours of injection, and × indicates that a number of scratches that affect the nozzle shape or dimensions exist. 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 jetting for 100 hours, and × the position was slightly aimed It is out of place, the shape is irregular, or microdroplets are scattered around. XX of the device performance is good (◯) or not (×) of electron emission after performing a forming process described later.
[0062]
[Table 2]

[0063]
[Table 3]

[0064]
[Table 4]

[0065]
[Table 5]

[0066]
From the above results, it can be seen that when the hardness of the contained metal fine particles is greater than the material of the discharge port (S3, S6), the discharge port is damaged. It can also be seen that the shape of the element formed thereby is poor and the element performance is also poor. Therefore, it can be seen that when such a surface conduction electron-emitting device is formed by a manufacturing apparatus such as the present invention, it is necessary to select a material for the metal fine particles that is softer than the member constituting the discharge port.
[0067]
Some of the scratches do not deteriorate the element shape due to the size of the discharge port. Like the reference head, there is a diameter of Φ36μm (= area is about 1000μm) ² In such a case, even if there are scratches, the discharge port diameter is large, so that the element shape is sufficiently usable, not the scratches that cause deterioration in the jetting performance.
[0068]
On the other hand, the discharge port diameter is 25 μm or less (= the area is about 500 μm) ² In the case of less than half of the reference head in the area comparison as in the case of (less than)), even if scratches are caused in the same way, 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.
[0069]
In other words, if the surface conduction electron-emitting device is not formed so fine, the problem of scratches does not affect the device performance, so there is no concern. However, as in the present invention, a liquid having a discharge port diameter of Φ25 μm or less. In the case where a solution containing 10 μm to 200 μm of metal fine particles is sprayed and applied by a droplet ejecting head to form a surface conduction electron-emitting device group using a conductive thin film, a flaw in the discharge port is a factor in 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. In other words, the metal fine particles need to be made of a material that is softer than the member constituting the discharge port.
[0070]
In the experiment, a round Φ25 μm nozzle (area is about 490 μm) ² ), Φ16μm nozzle (area is about 200μm) ² ), Φ10μm nozzle (area is about 80μm) ² ) Is used, however, when nozzles of other shapes (for example, rectangles) are used as the nozzles of the ejection head, their areas may be compared. For example, a 22 μm × 22 μm nozzle is a round shape of the present invention. This is equivalent to a 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 a surface conduction electron-emitting device group is formed by ejecting such a solution with an ejection head using less nozzles.
[0071]
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. Then, the present invention relates to a technique for forming a conductive thin film on a substrate by ejecting the solution from a fine discharge port by a technique equivalent to the so-called inkjet ejection principle. However, in the ink used in the conventional ink jet recording field, the dye is dissolved in the solution, whereas in the solution used in the present invention, since the metal fine particles are only dispersed in the solution, clogging occurs. Cheap.
[0072]
Furthermore, in the present invention, a fine discharge port diameter, for example, a discharge port diameter of Φ25 μm or less (500 μm in terms of area) is required because of the required use of an element (electron-emitting device). ² This clogging is a very serious problem.
[0073]
By the way, clogging originates from the principle itself that a solution is ejected from a fine discharge port. That is, it occurs 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 can be called foreign matter in the solution.
[0074]
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 has found out the relationship between the difficulty of clogging and their occurrence. Specifically, a solution in which the metal fine particle diameter was changed was prepared, and after using a jet head in which the size of the discharge port was known, droplet ejection was performed for a certain period of time, then left for a certain period of time, and droplet ejection was resumed, The discharge port was checked for clogging. In that case, not only a complete blockage of the outlet, but also a partial clogging and a prior indication (a slight clogging) were considered as clogging and tested.
[0075]
The used ejection head is equivalent to the thermal ink jet method using thermal energy, and is the one in which the nozzle plate is mounted on the ejection head of FIG. 6 as described above (nozzle plate is not shown). In FIG. 6, only four discharge ports are shown for simplicity of explanation. In actual use, 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.
[0076]
The recording heads were prepared from H1 to H4 (respective ejection port diameters were H1 = Φ25 μm, H2 = Φ20 μm, H3 = Φ15 μm, H4 = Φ10 μm). The nozzle plate was formed by Ni electroforming, and the thickness of the discharge port portion was all 30 μm.
[0077]
The solution used was ozone-treated with fine particles of palladium in an ozone generator with a voltage of 60 V, a frequency of 50 Hz, and an oxygen flow rate of 40 ml / min. 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. A solution for injection was prepared by changing the palladium fine particle diameter to 0.0003 to 0.5 μm and tested in combination with H1 to H4 having different discharge port diameters. Further, the condition for leaving after droplet ejection for a certain time (10 minutes) is to stand for 10 hours in an atmosphere of a temperature of 40 ° C. and a humidity of 30%.
[0078]
The following Tables 6 to 9 show the results of examining the occurrence of clogging by combining these solutions with different palladium fine particle diameters and heads H1 to H4 with different ejection port diameters. Table 6 shows the head H1 (discharge port diameter Do = Φ25 μm), Table 7 shows the head H2 (discharge port diameter Do = Φ20 μm), Table 8 shows the head H3 (discharge port diameter Do = Φ15 μm), and Table 9 shows the table 9. The case of the head H4 (discharge port diameter Do = Φ10 μm) is shown. Judgment ○ indicates that it can be used practically well, Δ indicates that it can be used but is not very preferable, and X indicates that it is not practical at all. When the palladium fine particle diameter was 0.0005 μm or less, it could not be stably dispersed and could not be evaluated.
[0079]
[Table 6]

[0080]
[Table 7]

[0081]
[Table 8]

[0082]
[Table 9]

[0083]
From the above results, when an ejection head having a discharge port diameter of Φ10 μm to Φ25 μm is used, there is no clogging if the palladium fine particle diameter Dp and the discharge port diameter Do satisfy the relationship of Dp / Do ≦ 0.01. It can be seen that stable droplet ejection can be obtained.
[0084]
Incidentally, although it is the lower limit value of Dp / Do, it is difficult for the palladium fine particle diameter Dp to be 0.0005 μm or less considering that such very fine metal fine particles are stably dispersed in the solution. In order to stably eject droplets to all ejection heads having an ejection orifice diameter of Φ25 μm or less, the lower limit value may be set to 0.0001 with a margin.
[0085]
In other words, if the metal fine particle diameter Dp and the discharge port diameter Do satisfy the relationship of 0.0001 ≦ Dp / Do ≦ 0.01, the conductive property by the droplet discharge using the discharge head having the discharge port diameter of Φ25 μm or less. It can be seen that a stable dispersion capable of forming a conductive thin film can be produced, and clogging can be prevented.
[0086]
In this experiment, a round discharge port (nozzle) was used. However, as described above, in the case of other shapes, the area may be compared. For example, in the case of a 22 μm × 22 μm rectangular discharge port 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 a surface conduction electron-emitting device group is formed by ejecting such a solution with an ejection head using less nozzles.
[0087]
In the experiment, a thermal ink jet (bubble jet (registered trademark)) type jet head was used, but the jet head used in the manufacturing apparatus of the present invention is not limited to this, and a piezo jet type using a piezoelectric element. Any method such as a method using an electrostatic force or a charge control method (continuous flow method) may be used.
[0088]
For example, in the case of a piezo jet method using a piezoelectric element, by always keeping the input voltage to the piezo element constant, round uniform droplets are obtained when the droplets fly, and good round dots are 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 deteriorated and there are few restrictions on the solution to be used.
[0089]
On the other hand, in the case of the thermal ink jet method, it flies with a small satellite droplet when the solution flies, but the speed at the time of flying is high (for example, 10 m / s to 20 m / s), and a merit that a stable jet flying can be 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.
[0090]
In other words, in the case of the thermal ink jet method, even if small satellite droplets are flying, if the input energy to the heating element is always constant, the total amount of solution to form one dot is It becomes the same (because it adheres to the same location), and a good round dot is obtained similarly.
[0091]
Next, still another feature of the present invention will be described. The electron-emitting device substrate of the present invention is manufactured by applying a fine particle-containing solution in which metal fine particles are dispersed in a solution on the substrate by flying in the air on the principle of ink jet. In order to form a high-quality electron-emitting device substrate, it is necessary to optimize the size of the surface roughness metal fine particles on the substrate when the dot pattern of the solution is formed by spraying and applying the solution.
[0092]
For example, the surface roughness of the substrate is the unevenness of the surface. As shown in FIG. 7, when particles having a size that protrudes from the unevenness adhere to the surface of the substrate, a good dot pattern, A good electron-emitting device will not be obtained. On the other hand, as shown in FIG. 8, a good dot pattern will be obtained if the particle size is not more than this unevenness.
[0093]
In the present invention, in view of this point, a dot pattern was formed on a substrate whose surface roughness was known in advance using a solution containing metal fine particles having different sizes, and the quality of the formed pattern was evaluated.
[0094]
In the experiment, Pyrex (registered trademark) glass was polished so that the surface roughness was 0.01 s to 0.02 s, and the palladium fine particle-containing solution (here, the fine particle diameter was adjusted) on the polished substrate. 0.0005 μm to 0.2 μm) is used in combination with the above-mentioned H4 jet head (nozzle diameter Φ10 μm) to form a pattern in which dots are connected, and the smoothness of the pattern is observed under a microscope. Then, sensory evaluation was performed, and good to good to bad (◯ to Δ to x) were judged.
[0095]
Details of the experimental conditions are shown below. The pattern is one row in the vertical direction, and about 100 dots of about Φ10 μm are implanted at a pitch of about 6 μm. The used ejection head is an H4 ejection head having 64 nozzles (discharge ports) and an arrangement density of 100 dpi. The ejection head and the substrate move relative to each other (here, the substrate is fixed and the ejection head is scanned by carriage), the control is controlled in μ order, and the timing of ejection is controlled. Went.
[0096]
The driving voltage for droplet ejection was 16V for the input voltage to the piezo element, and the driving frequency was 10 kHz. The volume of the spray droplet is always approximately 1.5 pl. Also, the droplet shape at the time of droplet flight is separately ejected and observed under the same conditions as pattern formation, and the drive waveform is such that the shape becomes a substantially round droplet immediately before adhering to the substrate surface (3 mm in the present invention example). Was controlled and sprayed. Even if a completely round spherical shape is not obtained and the columnar shape extends in the flight direction, the length l of the liquid column can be easily set to a length within three times the diameter by simply controlling the driving waveform (l ≦ 3d). At that time, a driving condition (driving waveform) without a plurality of minute droplets behind the flying droplet was selected.
[0097]
As described above, palladium fine particle-containing solutions having different fine particle diameters of 0.0005 μm to 0.2 μm were prepared and used (solution No. is common), but when the fine particle diameter is 0.02 μm or more. Since nozzle clogging started to occur, evaluation was performed by selecting only those patterns in which the clogging did not occur and the pattern was satisfactorily formed. The results are shown in Table 10 below.
[0098]
[Table 10]

[0099]
From the above results, it can be seen that the metal fine particles contained in the solution can form a smooth and favorable pattern by setting the size to be less than the surface roughness of the surface on which the pattern of the substrate is formed. On the other hand, when the size of the metal fine particles is larger than that, the smoothness of the pattern shape is impaired.
[0100]
Next, still another feature of the present invention will be described. As described above, the present invention manufactures an electron-emitting device by causing a fine particle-containing solution in which metal fine particles are dispersed in a solution to fly in the air on the principle of ink jet and applying it onto a substrate to form a pattern. There is a high-quality electron emission, however, the thickness of the pattern of the electron emission part formed by the solid content remaining after the volatile components in the droplet pattern formed by solution jetting or application of droplets or solution after volatilization remains. It is important to obtain an element. For example, the substrate on which the electron-emitting device is formed has a certain surface roughness, but in order to obtain a good electron-emitting device, the relationship between the thickness of the pattern and the surface roughness, that is, the unevenness of the surface is appropriately set. It is necessary to choose. The examination results are shown below.
[0101]
In the experiment, a Pyrex (registered trademark) glass substrate having a different surface roughness was prepared, and a solution containing palladium fine particles was combined with the above-described H4 jet head (nozzle diameter Φ10 μm) on a pair of device electrodes formed thereon. To form a pattern in which dots are joined together, and a device is formed by performing a forming process to be described later, and whether or not it actually functions well (good electron emission is obtained ... Not obtained ... x) was evaluated. In addition, in order to change the pattern film thickness, the solution has the above-mentioned No. No. 4 solution (palladium fine particle diameter Dp = 0.002 μm) was used 2 to 50 times diluted with pure water. As a result, it was possible to form electron-emitting devices having different pattern film thicknesses after a pattern was formed by spraying and application, and after drying and solid content remained.
[0102]
Details of the experimental conditions are shown below. The pattern is one row in the vertical direction, and four dots of about Φ10 μm are implanted at a pitch of about 6 μm. The ejection head and the substrate move relative to each other (here, the substrate is fixed and the ejection head is scanned by carriage), the control is controlled in μ order, and the timing of ejection is controlled. Went.
[0103]
The driving voltage for droplet ejection was 16V for the input voltage to the piezo element, and the driving frequency was 10 kHz. The volume of the spray droplet is always approximately 1.5 pl. Also, the droplet shape at the time of droplet flight is separately ejected and observed under the same conditions as pattern formation, and the drive waveform is such that the shape becomes a substantially round droplet immediately before adhering to the substrate surface (3 mm in the present invention example). Was controlled and sprayed. The results are shown in Table 11 below.
[0104]
[Table 11]

[0105]
From the above results, the electron-emitting device formed according to the principle of the present invention has a good electron-emitting device by making the thickness of the pattern of the electron-emitting portion more than the surface roughness of the substrate. It can be seen that
[0106]
In this way, after forming a pattern of a surface conduction electron-emitting device group having a good shape, in the present invention, the electron-emitting portion 5 is formed by a forming process as described below (FIGS. 1 and 2). reference).
[0107]
The electron emission 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 forming process conditions. The inside of the electron emission part 5 may contain conductive fine particles having a particle size of 100 mm or less.
[0108]
As an example of the forming treatment method applied to the conductive thin film 4, a method by energization treatment will be described. When energization is performed between the device electrodes 2 and 3 using a power source (not shown), an electron emission portion 5 having a changed structure is formed in a portion of the conductive thin film 4. That is, according to the energization forming, a region having a structural change such as local destruction, deformation, or alteration is formed in the conductive thin film 4, and this site becomes the electron emission portion 5.
[0109]
FIG. 9 is a diagram showing an example of the voltage waveform of the energization forming process as described above applied to the present invention. The voltage waveform is particularly preferably a pulse waveform. When a voltage pulse having a constant pulse peak value is applied continuously (FIG. 9A), or when a voltage pulse is applied while increasing the pulse peak value (FIG. 9). (B)). First, the case where the pulse peak value is a constant voltage (FIG. 9A) will be described.
[0110]
In FIG. 9A, T1 and T2 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 during energization forming) is surface conduction. It selects suitably according to the form of a type | mold electron-emitting element. Under such conditions, for example, a voltage is applied for several seconds to several tens of minutes. The pulse waveform is not limited to a triangular wave, and a desired waveform such as a rectangular wave may be used.
[0111]
In FIG. 9B, T1 and T2 indicate the pulse width and pulse interval of the voltage waveform, respectively, as shown in FIG. 9A, and the peak value of the triangular wave (peak voltage during energization forming) is, for example, It can be increased by about 0.1V step.
[0112]
The end of the energization forming process can be detected by applying a voltage that does not cause local destruction or deformation of the conductive thin film 4 during the pulse interval T2, and measuring the current. For example, the element current that flows when a voltage of about 0.1 V is applied is measured, and a resistance value is obtained.
[0113]
It is desirable to perform a process called an activation process on the element that has completed energization forming. By applying the activation process, the device current If and the emission current Ie change remarkably. The activation step can be performed, for example, by repeating the application of pulses in the same manner as the energization forming in an atmosphere containing an organic substance gas.
[0114]
The above atmosphere can be formed using organic gas remaining in the atmosphere when the vacuum container is discarded using, for example, an oil diffusion pump or a rotary pump. It can also be obtained by introducing a gas of a suitable organic substance into the vacuum. A preferable gas pressure of the organic material at this time is appropriately set according to the case because it varies depending on the application form, the shape of the vacuum container, the kind of the organic material, and the like.
[0115]
Examples of the organic substances include alkanes, alkenes, alkyne aliphatic hydrocarbons, aromatic hydrocarbons, alcohols, aldehydes, ketones, amines, organic acids such as phenol, carboxylic acid, and sulfonic acid. Specifically, C, such as methane, ethane, propane, etc. _n H _{2n + 2} Saturated hydrocarbon, ethylene, propylene, etc. represented by C _n H _2n An unsaturated hydrocarbon 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.
[0116]
By this treatment, carbon or a carbon compound is deposited on the element from an organic substance present in the atmosphere, and the element current If and the emission current Ie change remarkably. The end of the activation process is determined while measuring the device current If and the emission current Ie. The pulse width, pulse interval, pulse peak value, etc. are set as appropriate.
[0117]
Carbon or a carbon compound is graphite (refers to both single crystal and polycrystal) and amorphous carbon (amorphous carbon and carbon including a mixture of amorphous carbon and microcrystalline graphite). The film thickness is preferably 500 mm or less, more preferably 300 mm or less.
[0118]
The electron-emitting device thus produced is preferably subjected to a stabilization process. In this treatment, the partial pressure of the organic substance in the vacuum vessel is 1 × 10 ^-8 Less than Torr, preferably 1 × 10 ^-10 It is good to carry out below Torr. The pressure in the vacuum vessel is 10 ^-6 -10 ^-7 Torr or less is preferred, especially 1 × 10 ^-8 Torr or less is preferable. As the vacuum exhaust device for exhausting the vacuum vessel, it is preferable to use a device that does not use oil so that the oil generated from the device does not affect the characteristics of the element.
[0119]
Specifically, a vacuum exhaust apparatus such as a sorption pump or an ion pump can be used. Further, when the inside of the vacuum vessel is evacuated, it is preferable to overheat the whole vacuum vessel so that organic molecules adsorbed on the inner wall of the vacuum vessel or the electron-emitting device can be easily evacuated. The evacuation condition in the heated state at this time is preferably 80 to 200 ° C. for 5 hours or longer, but is not particularly limited to this condition, and various conditions such as the size and shape of the vacuum vessel and the configuration of the electron-emitting device. It depends on.
[0120]
The partial pressure of the organic substance is determined by measuring partial pressures of organic molecules mainly composed of carbon and hydrogen having a mass number of 10 to 200 using a mass spectrometer and integrating the partial pressures. After the stabilization process, the driving atmosphere is preferably maintained at the end of the stabilization process, but is not limited to this, and the degree of vacuum itself is sufficient if the organic substance is sufficiently removed. Sufficiently stable characteristics can be maintained even with a slight decrease. By adopting 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.
[0121]
Next, the image forming apparatus of the present invention will be described. Various arrangements of the electron-emitting devices of the electron source substrate used in the image forming apparatus can be adopted. First, each of a large number of electron-emitting devices arranged in parallel is connected at both ends, and a plurality of rows of electron-emitting devices are arranged (referred to as the row direction), and electrons are perpendicular to the wiring (referred to as the column direction). There is a ladder-type arrangement in which electrons from the electron-emitting device are controlled and driven by a control electrode (also referred to as a grid) arranged above the emitting device.
[0122]
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 connected in common to the wiring in the X direction, Examples include one in which the other of the electrodes of the plurality of electron-emitting devices arranged in the same column is commonly connected to the Y-direction wiring. Such is a so-called simple matrix arrangement. First, the simple matrix arrangement will be described in detail below.
[0123]
FIG. 10 is a diagram showing an example of an electron source substrate obtained by arranging a plurality of electron-emitting devices in a matrix, in which 10 is an electron source substrate, 14 is a substrate, 61 is an X-directional wiring, and 62 is Y 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, film thickness, and wiring width are appropriately set so that a substantially uniform voltage is supplied to the large number of surface conduction 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 (note that m and n are both positive integers). ).
[0124]
An 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 a part of a desired region. The X-direction wiring 61 and the Y-direction wiring 62 are respectively drawn 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-direction wirings 61 and the n Y-direction wirings 62 by connection 64. The material constituting the X-direction wiring 61 and the Y-direction wiring 62, the material constituting the connection 64, and the material constituting the pair of element electrodes are different from each other even if some or all of the constituent elements are the same. May be.
These materials are appropriately selected from, for example, the above-described element electrode materials. When the material constituting the element electrode and the wiring material are the same, the element electrode including the wiring connected to the element electrode can also be called an element electrode.
[0125]
The X-direction wiring 61 is electrically connected to scanning signal generating means (not shown) for applying a scanning signal for scanning a row of 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.
[0126]
Further, the driving voltage applied to each element of the surface conduction electron-emitting element 63 is supplied as a differential voltage between the scanning signal and the modulation signal applied to the element. As a result, individual elements can be selected and driven independently by simple matrix wiring.
[0127]
Next, an image forming apparatus using the electron source having the simple matrix arrangement created as described above will be described. FIG. 11 is a diagram for explaining an example of the basic configuration of the display panel of the image forming apparatus. In FIG. 11, 10 is an electron source substrate in which an electron-emitting device 63 is formed on the substrate, and 71 is an electron source substrate 10 fixed. 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 configured by sealing by baking at 400 to 500 degrees in air or nitrogen for 10 minutes or more.
[0128]
11, 63 is an electron-emitting device corresponding to the configuration shown in FIG. 1, and 61 and 62 are X-directional wiring and Y-directional wiring connected to a pair of device electrodes of the surface conduction electron-emitting device, respectively.
[0129]
The envelope 78 is constituted by the face plate 76, the support frame 72, and the rear plate 71 as described above. However, the rear plate 71 is provided mainly for the purpose of reinforcing the strength of the electron source substrate 10, and therefore the electron source substrate 10 is provided. If the substrate itself has sufficient strength, the separate rear plate 71 is not necessary, and the support frame 72 is sealed directly to the electron source substrate 10, and the face plate 76, the support frame 72, and the electron source substrate 10 are attached outside. The enclosure 78 may be configured.
Furthermore, an envelope 78 having sufficient strength against atmospheric pressure can be configured by installing an atmospheric pressure resistant support member called a spacer between the face plate 76 and the rear plate 71.
[0130]
In any case, such a face plate is laminated and integrated with the electron source substrate to constitute an image forming apparatus (image display apparatus), and thus has substantially the same shape and size as the electron source substrate.
[0131]
FIG. 12 is a schematic diagram showing a configuration example of a fluorescent film used in the image forming apparatus of FIG. 11, in which a black stripe type fluorescent film is shown in FIG. 12A and a black matrix type fluorescent film is shown in FIG. It is shown in In FIG. 12, 74 is a fluorescent film, 81 is a black conductive material, and 82 is a phosphor.
[0132]
The fluorescent film 74 is composed of only a phosphor in the case of monochrome, but in the case of a color fluorescent film, it is composed of a black conductive material 81 and a phosphor 82 called a black stripe or a black matrix depending on the arrangement of the phosphors. . The purpose of providing the black stripe and the black matrix is to make the mixed colors and the like inconspicuous by making the coloration portions between the phosphors 82 of the three primary color phosphors necessary for color display, It is to suppress a decrease in contrast due to light reflection.
[0133]
The material of the black stripe is not limited to the material that is not only a material mainly composed of graphite, which is usually used well, but also a material that is conductive and has little light transmission and reflection.
[0134]
In the present invention, the stripe directions of the matrix-like phosphors 82 as described above, or the two orthogonal directions of the matrix, and the two orthogonal directions of the electron-emitting devices 63 are parallel to each other. In addition, the electron-emitting devices 63 are positioned and laminated so that the phosphors 82 coincide with each other, thereby constituting an image display device.
Since the image display apparatus having such a configuration matches the directions and positions of the matrixes, a very high-quality image display apparatus can be realized.
[0135]
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. 12).
[0136]
The metal back 75 improves the brightness by specularly reflecting the light emitted from the phosphor toward the inner surface to the face plate 76 side, acts as an electrode for applying an electron beam acceleration voltage, It has a role of protecting the phosphor from damage caused by collision of negative ions generated in the vessel. The metal back 75 can be manufactured by preparing a fluorescent film 74, performing a smoothing process (usually called filming) on the inner surface of the fluorescent film 74, and then depositing Al by vacuum evaporation or the like. Further, the face plate 76 may be provided with a transparent electrode (not shown) on the outer surface side of the fluorescent film 74 in order to further increase the conductivity of the fluorescent film 74.
[0137]
When sealing to create the envelope 78 described above, in the case of a color, each color phosphor 82 and the electron-emitting device 63 must correspond to each other, and sufficient alignment is required. In order to perform this sufficient alignment, in the present invention, as described above, the phosphor 82 is disposed at a position facing the electron-emitting device 63 and the matrixes 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 adopts the same positioning method as the electron source substrate of the present invention.
[0138]
Specifically, the image forming apparatus shown in FIG. 11 is manufactured as follows. The envelope 78 is exhausted through an exhaust pipe (not shown) by an exhaust device that does not use oil, such as an ion pump or a sorption pump, while being appropriately heated, as in the stabilization step described above. ^-7 After making the atmosphere of an organic material having a sufficiently low degree of vacuum of Torr, sealing is performed.
[0139]
In some cases, a getter process is performed to maintain the degree of vacuum after sealing the envelope 78. This is because vapor deposition is performed 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 sealing the envelope 78. This is a process for forming a film. The getter is usually composed mainly of Ba or the like, and has an adsorption effect of the deposited film, for example, 1 × 10. ^-5 Torr or 1 × 10 ^-7 The degree of vacuum of Torr is maintained.
[0140]
Next, a schematic configuration showing an example of a drive circuit for driving a display panel configured 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. 13 is a block diagram of a drive circuit for performing display in accordance with an NTSC television signal, and represents an image forming apparatus including the drive circuit. In FIG. 13, 91 is an image display panel, 92 is a scanning circuit, 93 is a control circuit, 94 is a shift register, 95 is a line memory, 96 is a synchronizing signal separation circuit, 97 is a modulation signal generator, and Vx and Va are direct currents. It is a voltage source.
[0141]
Hereinafter, the function of each unit shown in FIG. 13 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. Among these, the terminals Dox1 to Doxm sequentially drive the electron source 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 in a row (N elements). A scanning signal for applying is applied.
[0142]
On the other hand, a modulation signal for controlling the output electron beam of each element of the surface conduction electron-emitting elements in one row selected by the scanning signal is applied to the terminals Doy1 to Doyn. The high-voltage terminal Hv is supplied with a DC voltage of, for example, 10 kV from the DC voltage source Va, which gives sufficient energy to excite the phosphor to the electron beam output from the surface conduction electron-emitting device. Accelerating voltage for
[0143]
Next, the scanning circuit 92 will be described. The circuit includes M switching elements therein (schematically indicated by S1 to Sm in the figure), and each switching element is either the output voltage of the DC voltage source Vx or 0V (ground level). One is selected and electrically connected to the terminals Dox1 to Doxm of the display panel 91.
[0144]
Each of the switching elements S1 to Sm operates based on the control signal Tscan output from the control circuit 93. In practice, however, it can be configured by combining switching elements such as FETs. The DC voltage source Vx has a driving voltage applied to an unscanned element equal to or lower than the electron emission threshold voltage based on the characteristics (electron emission threshold voltage) of the surface conduction electron-emitting device. It is set to output such a constant voltage.
[0145]
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 synchronization signal Tsync sent from a synchronization signal separation circuit 96 to be described later, Tscan, Tsft, and Tmry control signals are generated for each unit.
[0146]
The synchronization signal separation circuit 96 is a circuit for separating the synchronization signal component and the luminance signal component from the NTSC television signal input from the outside, and can be configured by using a frequency separation (filter) circuit. The synchronization signal separated by the synchronization signal separation circuit 96 is composed of a vertical synchronization signal and a horizontal synchronization 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 represented as a DATA signal for convenience, and this signal is input to the shift register 94.
[0147]
The shift register 94 is for serial / parallel conversion of the DATA signal input serially in time series for each line of the image, and operates based on the 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. Data for one line (corresponding to drive data for N electron-emitting devices) subjected to serial / parallel conversion is output from the shift register 94 as N parallel signals Id1 to Idn.
[0148]
The line memory 95 is a storage device for storing data for one line of the image for a necessary time, and appropriately stores the contents of Id1 to Idn according to the 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.
[0149]
The modulation signal generator 97 is a signal source for appropriately driving and modulating each of the surface conduction electron-emitting devices according to each of the image data Id′1 to Id′n, and an output signal thereof is output from the terminals Doy1 to Doy1. The voltage is applied to the surface conduction electron-emitting device in the display panel 91 through Doyn.
[0150]
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, there is a clear threshold voltage Vth for electron emission, and electron emission occurs only when a voltage higher than Vth is applied. Further, for a voltage higher than the electron emission threshold, the emission current also changes in accordance with the change in the voltage applied to the device. Note that the value of the electron emission threshold voltage Vth and the degree of change in the emission current with respect to the applied voltage may change by changing the material, configuration, and manufacturing method of the electron-emitting device. I can say that.
[0151]
That is, when a pulse voltage is applied to the device, for example, electron emission does not occur even when a voltage lower than the electron emission threshold is applied, but when a voltage higher than the electron emission threshold is applied, A beam is output. At that time, first, it is possible to control the intensity of the output electron beam by changing the peak value Vm of the pulse, and secondly, the electron beam output by changing the pulse width Pw. It is possible to control the total amount of charge.
[0152]
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, etc. In order to implement the voltage modulation method, the modulation signal generator 97 has a certain length. A voltage modulation circuit that modulates the peak value of the pulse as appropriate according to the input data is used. 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 appropriately modulates the width of the voltage pulse according to input data. A modulation circuit is used.
[0153]
The shift register 94 and the line memory 95 may be of a digital signal type or an analog signal type, and the serial / parallel conversion and storage of the image signal may be performed at a predetermined speed.
[0154]
In the case of using a digital signal type, it is necessary to convert the output signal DATA of the synchronization signal separation circuit 96 into a digital signal. If the output part of the synchronization signal separation circuit 96 includes an A / D converter, Is possible. Further, 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.
[0155]
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 amplifier 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 from 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 driving voltage of the surface conduction electron-emitting device may be added.
[0156]
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 or the like 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 method, for example, a well-known voltage controlled oscillation circuit (VCO) may be used, and an amplifier for amplifying the voltage to the driving voltage of the surface conduction electron-emitting device is added if necessary. May be.
[0157]
In the image display device having the above-described configuration, each electron-emitting device of the display panel 91 emits electrons by applying a voltage through the external terminals Dox1 to Doxm and Doy1 to Doyn, and also outputs the high-voltage terminal Hv. Then, a high voltage is applied to the metal back 75 or the transparent electrode (not shown) to accelerate the electron beam, collide with the fluorescent film 74, and excite and emit light to display an image.
[0158]
The configuration described here is a schematic configuration necessary for producing a suitable image forming apparatus used for display or the like. For example, detailed portions such as materials of each member are not limited to the above-described contents, and the image It selects suitably so that it may be suitable for the use of a forming apparatus. Further, although the NTSC system has been exemplified as an input signal example, the present invention is not limited to this, and various systems such as the PAL and SECAM systems may be used, and more than this, a TV signal (for example, MUSE) composed of a large number of scanning lines. A high-definition TV system such as a system may be used.
[0159]
Next, a ladder-type arrangement electron source substrate and an image display device will be described. FIG. 14 is a schematic diagram showing a configuration example of an electron source substrate in which electron-emitting devices are arranged in a ladder shape, in which 100 is an electron source substrate, 14 is a substrate, 63 is an electron-emitting device, and 98 is an electron-emitting device 63. Common wiring composed of Dx1 to Dx10 connected to. A plurality of electron-emitting devices 63 are arranged in parallel in the X direction on the substrate 14 (this arrangement is called an element row).
[0160]
A plurality of the element rows are arranged on the substrate to constitute the electron source substrate 100. By applying a driving voltage between the common lines 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 where an electron beam is to be emitted, and a voltage equal to or lower than an electron emission threshold may be applied to an element row where no electron beam is emitted. Further, the common wirings Dx2 to Dx9 between the element rows, for example, Dx2 and Dx3, may be the same wiring.
[0161]
FIG. 15 is a diagram for explaining a panel structure in an image display device having a ladder-type arrangement electron source substrate as shown in FIG. 14, in which 100 is an electron in which 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 made of Dox1, Dox2, ... Doxm, 104 is G1, G2, ... Gn connected to the grid electrode 101 Other parts having the same functions as those in FIG. 11 or FIG. 14 are denoted by the same reference numerals.
[0162]
The image display apparatus shown in FIG. 15 is different from the image display apparatus (FIG. 11) having the simple matrix arrangement described above in 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 allows the electron beam to pass through a striped electrode provided perpendicular to the element row of the ladder type arrangement. One circular opening 102 is provided corresponding to each element.
[0163]
The grid shape and installation position are not limited to those shown in FIG. For example, a large number of mesh openings can be provided as openings, and a grid can be provided around or in the vicinity of the surface conduction electron-emitting device. The container outer terminal 103 and the grid container outer terminal 104 are electrically connected to a control circuit (not shown).
[0164]
In this image forming apparatus, a modulation signal for one image line is simultaneously applied to the grid electrode columns in synchronization with the sequential driving (scanning) of the element rows one by one. Thereby, irradiation of the phosphors with each electron beam can be controlled, and an image can be displayed line by line. According to this, in addition to a display device such as a television broadcast display device, a video conference system, and a computer, it can also be used as an image forming device as an optical printer configured using a photosensitive drum or the like.
[0165]
【The invention's effect】
As detailed above, on the substrate A pair of A droplet of a solution containing a material for forming a conductive thin film between element electrodes is ejected and applied by a droplet ejection head having a discharge port diameter of Φ25 μm or less, and the droplet after application Dot pattern A solution containing a material for forming the conductive thin film in an electron source substrate manufacturing apparatus for forming a surface conduction electron-emitting device group by volatilizing a volatile component therein and leaving a solid content on the substrate Is a solution in which metal fine particles are dispersed in a liquid, and the metal fine particles are Dot pattern When the size of the metal fine particles is Dp and the diameter of the discharge port is Do, 0.0001 ≦ Dp / Do ≦ 0.01. Thus, it is possible to provide a novel electron source substrate manufacturing apparatus that can be used stably for a long period of time when clogging does not occur.
[0166]
In addition, Dot pattern Therefore, the electron-emitting device formed is of high quality and an electron source substrate capable of good electron emission can be manufactured.
[0167]
According to invention of Claim 2, on a board | substrate A pair of A solution containing a material for forming a conductive thin film between element electrodes is sprayed and applied by a solution jet head having a discharge port diameter of Φ25 μm or less, and the solution after the application Dot pattern by A solution containing a material for forming the conductive thin film in an electron source substrate manufacturing apparatus for forming a surface conduction electron-emitting device group by volatilizing a volatile component therein and leaving a solid content on the substrate Is a solution in which metal fine particles are dispersed in a liquid, and the metal fine particles are Dot pattern When the size of the metal fine particles is Dp and the diameter of the discharge port is Do, 0.0001 ≦ Dp / Do ≦ 0.01. Thus, it is possible to provide a novel electron source substrate manufacturing apparatus that can be used stably for a long period of time when clogging does not occur.
[0168]
In addition, Dot pattern Therefore, the electron-emitting device formed can be of high quality and an electron source substrate capable of good electron emission can be manufactured.
[0169]
According to the third aspect of the present invention, in the solution used in such an electron source substrate manufacturing apparatus, the solution containing the metal fine particles for forming the conductive thin film contained in the solution is the metal. When the size of the fine particles is Dp and the discharge port diameter is Do, 0.0001 ≦ Dp / Do ≦ 0.01, and the metal fine particles are formed on the substrate. Dot pattern Since the size is equal to or smaller than the surface roughness of the surface on which is formed, clogging does not occur when the solution is sprayed, and a high-quality electron source substrate can be manufactured stably.
[0170]
According to the fourth aspect of the present invention, in the electron source substrate manufactured by such an electron source substrate manufacturing apparatus, a metal is used as a material for forming a conductive thin film between a plurality of pairs of element electrodes on the substrate. In an electron source substrate manufactured by an electron source substrate manufacturing apparatus that forms a surface conduction electron-emitting device group by spraying and applying a solution containing fine particles with a droplet jet head having a discharge port diameter of Φ25 μm or less, the conductive thin film is Volatilizes solvent components after application of solution Dot pattern A thin film, A crack occurred in a part of the dot pattern A thin film containing fine metal particles, wherein the fine metal particles are Dot pattern 0.0001 ≦ Dp / Do ≦ 0.01, where the size is not more than the surface roughness of the surface on which the thin film is formed, the size of the metal fine particles is Dp, and the discharge port diameter is Do.
Therefore, it is possible to provide a novel electron source substrate manufacturing apparatus that can be stably used for long-term use in which clogging does not occur during solution injection.
[0171]
In addition, since the thickness of the thin film is equal to or greater than the surface roughness, the formed electron-emitting device has a high quality and can be an electron source substrate capable of good electron emission.
[0172]
According to the invention described in claim 5, by using an electron source substrate having a high-quality and highly reliable surface conduction electron-emitting device pattern and excellent electron-emitting device characteristics, high-quality and durable An image display device with high performance can be obtained.
[Brief description of the drawings]
1A and 1B are schematic views showing a configuration of a planar surface conduction electron-emitting device according to an embodiment of the present invention, in which FIG. 1A is a plan view, and FIG. 1B is a sectional view taken along line BB in FIG. It is.
2A and 2B are schematic views for explaining a method of manufacturing the surface conduction electron-emitting device shown in FIG. 1, FIG. 2A is a diagram in which device electrodes are formed on a substrate, and FIG. 2B is a conductive thin film on the device electrodes. (C) is a diagram in which an electron emission portion is formed in a conductive thin film.
FIG. 3 is a configuration diagram showing an example of an electron source substrate manufacturing apparatus according to the present invention.
FIG. 4 is a diagram for explaining an example of a configuration of a droplet applying device to which the present invention can be applied.
FIGS. 5A and 5B are schematic views of the main part of a discharge head unit of the droplet applying device of FIG.
FIGS. 6A to 6C are views showing an example of an ejection head used in the apparatus for manufacturing a surface conduction electron-emitting device according to the present invention. FIGS.
FIG. 7 is a diagram schematically showing the relationship between metal fine particles and surface roughness when a dot pattern is formed with a solution containing metal fine particles larger than the surface roughness of the substrate.
FIG. 8 is a diagram schematically showing the relationship between metal fine particles and surface roughness when a dot pattern is formed by a solution containing metal fine particles having a size equal to or smaller than the surface roughness of the substrate.
FIGS. 9A and 9B are diagrams showing examples of voltage waveforms in the energization forming process that can be employed in the manufacture of the surface conduction electron-emitting device according to the present invention. FIGS.
FIG. 10 is a schematic view showing an example of a matrix-arranged electron source substrate to which the present invention can be applied.
FIG. 11 is a diagram 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. 12A and 12B are schematic diagrams illustrating a configuration example of a fluorescent film used in an image forming apparatus to which the present invention can be applied, in which FIG. 12A is a black stripe type fluorescent film, and FIG. 12B is a black matrix type fluorescent film. It is a membrane.
FIG. 13 is a block diagram illustrating an example of a drive circuit for performing display on the image forming apparatus according to an NTSC television signal.
FIG. 14 is a schematic diagram showing an example of a ladder-type arrangement electron source substrate to which the present invention can be applied.
FIG. 15 is a diagram for explaining an example of a basic configuration of a display panel of an image forming apparatus using a ladder type electron source substrate to which the present invention can be applied.
FIG. 16 is a diagram showing an example of a conventional electron-emitting device.
[Explanation of symbols]
1 Substrate
2, 3 element electrodes
4 Conductive thin film
5 Electron emission part
10 Electron source substrate
11 Discharge head unit (jet 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 of 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 adjustment mechanism
35 Control computer
36 Image recognition mechanism
37 XY direction 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 Ejection head (inkjet head)
51 Heating element substrate
52 Lid substrate
53 Silicon substrate used for producing heating element substrate 51
54 Individual electrodes
55 Common electrode
56 Heating element
57 Solution inlet
58 nozzles
59 Groove
60 recessed area
61 X direction wiring
62 Y-direction wiring
63 Surface-conduction electron-emitting device
64 connection
71 Rear plate to which the electron source substrate 10 is fixed
72 Support frame
73 Glass substrate
74 Fluorescent membrane
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 Sync 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 in which common wiring between element rows is the same wiring
101 Grid electrode
102 Opening for electrons to pass through
103 Dox1, Dox2 ... Dokm outer terminal
104 Container outer terminal composed of G1, G2... Gn connected to the grid electrode 101
Vx, Va DC voltage source

Claims (5)

Droplets of a solution containing a material for forming a conductive thin film between a pair of device electrodes injection imparted by the discharge diameter Φ25μm following droplet ejection head on the substrate, after application of the droplet in the dot pattern of In an electron source substrate manufacturing apparatus for forming a surface conduction electron-emitting device group by volatilizing a volatile component and leaving a solid content on the substrate,
The solution containing the material for forming the conductive thin film is a solution in which metal fine particles are dispersed in a liquid, and the metal fine particles have a size equal to or smaller than the surface roughness of the surface on which the dot pattern is formed. When the size of the metal fine particles is Dp and the discharge port diameter is Do, 0.0001 ≦ Dp / Do ≦ 0.01, and the thickness of the dot pattern is equal to or greater than the surface roughness. An electron source substrate manufacturing apparatus characterized by controlling injection. A solution containing a material for forming a conductive thin film between a pair of element electrodes on a substrate is sprayed and applied by a solution jet head having a discharge port diameter of Φ25 μm or less, and the volatile components in the dot pattern are volatilized by the applied solution. In the electron source substrate manufacturing apparatus for forming the surface conduction electron-emitting device group by leaving the solid content on the substrate,
The solution containing the material for forming the conductive thin film is a solution in which metal fine particles are dispersed in a liquid, and the metal fine particles have a size equal to or smaller than the surface roughness of the surface on which the dot pattern is formed. When the size of the metal fine particles is Dp and the discharge port diameter is Do, 0.0001 ≦ Dp / Do ≦ 0.01, and the thickness of the dot pattern is equal to or greater than the surface roughness. An electron source substrate manufacturing apparatus characterized by controlling injection. A solution containing metal fine particles as a material for forming a conductive thin film between a pair of element electrodes on a substrate is sprayed and applied by a droplet jet head having a discharge port diameter of Φ25 μm or less, and volatilization in a dot pattern by the solution after the application In a solution containing metal fine particles used for an electron source substrate manufacturing apparatus for forming a surface conduction electron-emitting device group by volatilizing components and leaving a solid content on the substrate,
When the size of the metal fine particle is Dp and the discharge port diameter is Do, 0.0001 ≦ Dp / Do ≦ 0.01, and the metal fine particle is formed on the surface of the substrate on which the dot pattern is formed. A fine particle-containing solution having a surface roughness or less. A solution containing metal fine particles as a material for forming a conductive thin film between a pair of device electrodes on a substrate is sprayed and applied by a droplet jet head having a discharge port diameter of Φ25 μm or less to form a surface conduction electron-emitting device group. In an electron source substrate manufactured by an electron source substrate manufacturing apparatus,
The conductive thin film is a thin film having a dot pattern formed by volatilizing a solvent component after application of the solution, and a thin film containing fine metal particles that have cracked in a part of the dot pattern , and the fine metal particles are 0.0001 ≦ Dp / Do ≦ 0.01 where the size of the surface on which the thin film of the dot pattern is formed is equal to or less than the surface roughness, the size of the metal fine particles is Dp, and the discharge port diameter is Do. The electron source substrate is characterized in that the thickness of the thin film of the dot pattern is equal to or greater than the surface roughness.   An electron source substrate according to claim 4, a face plate having a shape and a size substantially the same as those of the electron source substrate, mounted with a phosphor, arranged facing the electron source substrate. Image display device.

Images