JP3608291B2

JP3608291B2 - Electron source and cathode ray tube using the same

Info

Publication number: JP3608291B2
Application number: JP12173996A
Authority: JP
Inventors: 真嗣川渕; 彰彦細野; 信介由良; 和敏森川; 荘一郎奥田; 昿嗣原田
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 1995-05-30
Filing date: 1996-05-16
Publication date: 2005-01-05
Anticipated expiration: 2016-05-16
Also published as: JPH0950758A

Description

【０００１】
【発明の属する技術分野】
この発明は、ＣＲＴ型ディスプレイ、真空管、半導体製造装置等に用いられる電界放出型の電子源及びそれを用いた陰極線管に関するものである。
【０００２】
【従来の技術】
従来、電子源としては熱フィラメントからの熱電子放出等を利用したものが多用されていたが、画像表示装置の薄型化、軽量化に伴って、半導体の微細加工技術を利用した電界放出型（フィールドエミッタ）の電子源の開発が注目されてきた。
【０００３】
図２７は、例えば特開平２−２２６６３５号公報に記載された従来の電界放出電子源の一部の構成を示す断面図である。図において、電子放出部を形成するエミッタ１０４はカソード電極である基板１０１を加工して円錐形状に形成されている。エミッタ１０４を取り囲むように基板１０１上に絶縁膜１０５、引出し電極１０２、絶縁膜１０６、集束電極１０３、絶縁膜１０７、加速電極１０８が順に積層されている。引き出し電極１０２と基板１０１の間に印加された電圧（電源１０９からの電圧）により電子がエミッタ１０４の先端から引き出され、電源１１０により集束電極１０３に印加された電圧により電子は集束され、さらに電源１１１により加速電極１０８に印加された電圧により電子は加速され、電子線１００となって放出される。本実施例では電極が引出し電極、集束電極、加速電極の３層構造となってそれぞれ異なる電位が印加されるが、引出し電極さえあれば、電子放出は実現する。
【０００４】
次に電子源の動作について説明する。引き出し電極１０２に電源１０９によりカソード電極（基板）１０１に対し、正の例えば１００Ｖの電圧を印加すると、エミッタ１０４の先端には約１０^７Ｖ／ｃｍの電界が発生し、トンネル効果によりエミッタ１０４より電子が放出される。放出された電子による電流の大きさは１つのエミッタ当たり２５〜１００μＡで、エミッタ１０４の密度しだいで高い電流密度を得ることができる。しかも、引き出し電極１０２にはほとんど電流が流れないため、消費電力は極めて小さい。
【０００５】
ところで、上記のような電界放出電子源では、エミッタ１０４先端の形状を反映した電界分布の影響により放出電子線１００は発散する。そのため集束電極１０３に電源１１０によりカソード電極１０１と同程度の電位を加え放出電子を減速して放出電子線１００を集束できるように工夫している。これを電源１１１により正の電位を加えた加速電極１０８で加速し放出させる。ただし、個々のエミッタに加速電極１０８を設けずに外部の陽極で電子を加速させることもできる。
【０００６】
このような素子は写真製版と薄膜技術を用いれば数μｍ〜１０μｍの間隔で１００万個程度のエミッタアレイを同時に作製することができ、ピーク電流１００Ａの電子源が得られる。しかも、その電子源はカソード電極１０１を放出電流が流れることによる消費電力以外は電力損失はなく、電子線も発散しない低エミッタンスのものが得られる。
【０００７】
次に、このような従来の電界放出電子源の形成方法について説明する。電界放出電子源の形成方法については、例えば雑誌”１９９０年電子情報通信学会秋季全国大会予稿集（１９９０年）ｐ．５−２８２”や”第７回真空マイクロエレクトロニクスに関する国際会議の論文集，７ｔｈＩｎｔｅｒｎａｔｉｏｎａｌＶａｃｕｕｍＭｉｃｒｏｅｌｅｃｔｒｏｎｉｃｓＣｏｎｆｅｒｅｎｃｅ１９９４Ｊｕｌｙｐ．２５〜２８”に掲載されている。図２８は、”第７回真空マイクロエレクトロニクスに関する国際会議の論文集，７ｔｈＩｎｔｅｒｎａｔｉｏｎａｌＶａｃｕｕｍＭｉｃｒｏｅｌｅｃｔｒｏｎｉｃｓＣｏｎｆｅｒｅｎｃｅ１９９４Ｊｕｌｙｐ．２５〜２８”に記載された電界放出電子源の形成方法を示す断面工程図である。図において、（ａ）〜（ｆ）は工程の順を示す。まず、Ｓｉのような半導体（あるいはＡｌのような導体）基板１０１上にフォトレジスト１１３ａを用いてＳｉＯ_２の円形状のマスク１１２を形成する（工程（ａ））。マスク１１２を用いてＳｉ基板１０１を等方性エッチングし、その後基板表面を熱酸化させる。すると図中（ｂ）の基板１０１の表面に沿って酸化膜１０１ａが形成される（工程（ｂ））。次にその上にＳｉＯ_２絶縁層１０５及び例えばＮｂからなる電極１０２を形成する（工程（ｃ））。電極１０２には接続端子部を設けるためにさらにフォトレジスト１１３ｂを設け（工程（ｄ））、ＳｉＯ_２絶縁層１０６及び例えばＮｂからなる電極１０３を形成する（工程（ｅ））。最後にフォトレジスト１１３ｂを除去、及びＳｉＯ_２の円形状のマスク１１２をフッ酸で除去すると、基板１０１上の酸化膜１０１ａの一部も除去され、図中（ｆ）のような先端形状の鋭い円錐形状のエミッタ１０４が得られる。
【０００８】
一例として、エミッタ１０４の位置する電子放出部の開口直径は２〜３μｍ、円錐の高さは１μｍ、円錐の先端径は０．０６μｍである。また、電極１０２、１０３の厚さは、電圧が印加できるだけの厚さであれば厚くする必要もないため、通常約０．１〜０．３μｍである。また、絶縁層１０５はエミッタ１０４の先端から効率よく電子放出を行うために、エミッタの高さとほぼ同じに設定してあり（１μｍ）、絶縁層１０６の厚さも電極１０２と電極１０３間の絶縁耐圧を考慮し、絶縁層１０５と同じ１μｍに設定してあるのが通常である。
【０００９】
上記のような電子源の適用例としてはＣＲＴの電子銃が考えられる。この種の電子源をＣＲＴヘ適用した例は、特開昭４８ー９０４６７号公報に述べられている。ただし電子源としては、個々のエミッタ１０４に引き出し電極１０２以外に集束電極１０３を設けるという構成は述べられていない。図２９に、電子銃の構成を示す。図において、電子源（フィールドエミッタからなる電子源）１２１から放出された電子線は加速のための第１アノード電極１２２、第２アノード電極１２３を通過し、電子レンズ１２４、１２５でクロスオーバー点１２７を形成し、コンバージェンス電極１２６で集束され、さらに偏向マグネット１２８により方向制御されてシャドウマスク１２９を通ってアルミバック１３０付き蛍光体１３１の蛍光面に集束される。
【００１０】
一方、出願人はフィールドエミッタ型の電子源に関する発明として、特開平５−１９８２７８号公報において、簡便な素子構成で２次元画素のアドレッシングを容易に行え、製作が容易な電子源を用いた平面パネル型ディスプレイについての発明を既に出願している。さらに、特願平６−２４０１６９号において、電子源の集束特性を向上させるために集束電極に対向して遮蔽電極を配置した電界放出電子源を陰極線管に適用する発明を既に出願している。
【００１１】
【発明が解決しようとする課題】
従来の電界放出型の電子源は上記のように構成されていたので、集束特性の優れた電子線を得るためには集束電極１０３に所望の電位を与える必要がある。電位の与え方として引出し電極より高い電位を与える場合、数ｋＶオーダの高電圧が必要となり、引出し電極と集束電極の間の絶縁層を絶縁耐圧まで厚くする必要がありさらに、消費電力が高くなるという問題があった。そのため、集束電極に与える電位としては引出し電極より小さい電位、例えば、引出し電極１００Ｖに対して集束電極０Ｖを与えていた。しかし、集束電極の電位を引き出し電極に加える電位より低くすると、集束電極に与える電位の影響を受けて、エミッタ先端の電界が低下してトンネル効果により放出される電子が極端に減少するという問題が生じた。図３０に、集束電極に与える電位に対するアノ−ド電流と電子ビ−ムの発散角の変化を調べた実験結果を示す。図は集束電極の電圧１００Ｖでの値で規格化して示している。集束電極へ印加する電圧が高い程アノ−ド電流は大きく、即ち十分な電子線強度が得られ、一方電子ビ−ムは発散してしまう。集束電極へ印加する電圧を小さくすると、電子ビ−ムは集束するものの、電流値は激減してしまう。
【００１２】
本願発明は上記のような問題を解決するためになされたもので、集束電極に与える電圧を小さくしてもアノード電流が低下しないような、高電流密度で且つ集束特性の良好な性能の優れた電子源を提供することを目的とする。即ち、集束電極に与える電圧の影響をエミッタに及ぼさないような電子源の構造を与え、さらに、その高性能な電子源を搭載した陰極線管を提供することを目的とする。
【００１５】
【課題を解決するための手段】
この発明に係わる電子源は、略円錐形状の電子放出部を有するカソード電極上に、開口部を形成して電子放出部を囲むように順に第１の絶縁層、カソード電極部から電子を引き出すための引き出し電極、第２の絶縁層、引き出された電子を集束するための集束電極が配置され、前記集束電極に印加された電位により形成された電界のカソード電極の電子放出部への影響を遮蔽する手段を備え、前記集束電極に印加された電位により形成された電界のカソード電極の電子放出部への影響を遮蔽する手段が、カソード電極の略円錐形状の電子放出部の高さに対する引き出し電極の厚さの比が０．５以上の厚さの引き出し電極であることを規定するものである。
【００１６】
また、集束電極に印加された電位により形成された電界のカソード電極の電子放出部への影響を遮蔽する手段が、カソード電極の略円錐形状の電子放出部の高さに対する引き出し電極の厚さの比が１以上の厚さの引き出し電極であることを規定するものである。
【００１８】
また、集束電極に印加された電位により形成された電界のカソード電極の電子放出部への影響を遮蔽する手段が、カソード電極の略円錐形状の電子放出部の高さに対する第２の絶縁層の厚さの比が２．５以上の厚さの第２の絶縁層であることを規定するものである。
【００１９】
また、集束電極に印加された電位により形成された電界のカソード電極の電子放出部への影響を遮蔽する手段が、集束電極と引き出し電極（第１の引き出し電極）の間に第２の引き出し電極を備え、引き出し電極（第１の引き出し電極）と第２の引き出し電極とを同電位とし、引き出し電極（第１の引き出し電極）と第２の引き出し電極とを開口部の内面で接続したことであることを規定するものである。
【００２０】
また、集束電極に印加された電位により形成された電界のカソード電極の電子放出部への影響を遮蔽する手段が、集束電極と同一平面上で、かつ前記集束電極の開口部側に第２の引き出し電極を備えたことであることを規定するものである。
【００２１】
また、引き出し電極（第１の引き出し電極）と第２の引き出し電極とを同電位としたことを規定するものである。
【００２２】
また、引き出し電極（第１の引き出し電極）と第２の引き出し電極とを開口部の内面で接続したこと規定するものである。
【００２３】
また、引き出し電極（第１の引き出し電極）と第２の引き出し電極とを開口部の外部で接続したことを規定するものである。
【００２４】
また、第２の引き出し電極に印加する電位は、引き出し電極（第１の引き出し電極）に印加する電位より高くしたことを規定するものである。
【００２５】
また、この発明に係わる陰極線管は、真空容器内に、上記構成のいずれかの電子源と、該電子源から出射された電子線を集束する手段と、集束された電子線を蛍光体の所定の位置に偏向して導く手段とを備えたものである。
【００２７】
【発明の実施の形態】
実施の形態１．
以下、この発明の実施の形態１を図について説明する。図１は実施の形態１による電子源の要部を示す断面図であり、図２は電極の結線状態を示す概略平面図である。図において、例えばガラス材からなる基板１４上にカソード電極１１を構成するシリコン基板を固着し、この表面を加工して、円錐状のフィールドエミッタ１５を得る。電子源はこのエミッタを有する開口部１０の周りの基板１４上に、フィールドエミッタ１５に電界を印加して電子を引き出す引き出し電極１２、引き出された電子の向きを揃えるための電子レンズを形成する集束電極１３がそれぞれ第１絶縁膜１７、第２絶縁膜１６を介して積層されている。なお、開口１０とフィールドエミッタ１５は、例えば７．５μｍピッチで直径２００μｍの領域に配列されており、その数は図では省略しているが６００個以上である。フィールドエミッタ１５の先端は図１中に示したようにほぼ引き出し電極１２の下面と同程度の高さにある。
【００２８】
さらに、図２に示すように、集束電極１３は上方から見ると中心部に開口１０部すなわち電子放出領域のある直径４００μｍの円形となるように形成されている。ただし１ケ所、ボンディング端子（電極端子）２３へ接続する線状の配線２２が伸びて上部の空間に露出している。同様に引き出し電極１２およびカソード電極１１のボンディング端子（電極端子）１９、１８も空間に露出しており、これらの端子１９、１８と電極を接続する線状の配線２１、２０も引き出し電極１２、カソード電極１１の外側まで伸びている。さらに、ボンディング端子１８、１９、２３には電圧を供給する導線２６、２４、２５がそれぞれ接続されている。このように各電極１１、１２、１３に給電する端子部を構成するボンディング用端子１８、１９、２３や配線２０、２１、２２や導線２６、２４、２５の一部が電子放出空間側に露出している。
【００２９】
次にこの電子源の動作について説明する。引き出し電極１２にカソード電極１１に対し＋６０〜＋１１０Ｖの電圧を印加する。また、集束電極１３にはカソード電極１１に対し０〜＋２０Ｖの電圧を印加する。この際に、引き出し電極１２が十分厚いため、エミッタ１５先端の電界を低下させる集束電極１３からの電界の影響を遮蔽することができ、集束電極１３からの電界の影響を低減できる。図３は、引き出し電極（ゲート電極）の厚さとエミッタ先端から放出される電流との関係を示す、差分法を用いた電界解析結果である。横軸は引き出し電極（ゲート電極）１２の厚さとエミッタ１５の高さの比で、縦軸はエミッタ１５先端から放出される電流値を集束電極１３を用いない時の電流値を１００％として規格化したものである。図中Ａ点は、集束電極１３を用い且つ、従来の膜厚条件（エミッタ高さ１μｍ、ゲート電極の厚さ０．３μｍ）での放出電流の比で、引き出し電極１２の厚みを厚くすることでエミッタ１５先端から放出される電流が増加することがわかる。例えば、引き出し電極（ゲート電極）１２の厚さとエミッタ１５の高さの比が２以上では放出電流を８０％以上を確保できる。このように引き出し電極（ゲート電極）を厚くすることで、電流密度が高く集束特性の優れた電子線が得ることができる。
【００３０】
一方、引き出し電極（ゲート電極）を厚くすると、図１におけるエミッタ間のピッチｐが広がり、複数のエミッタを形成して電子源とする際の単位面積当たりのエミッタ数が減少する。そのため、複数のエミッタを形成して電子源として用いる場合、全てのエミッタからの放出電流の合計は、１個当たりのエミッタからの放出電流とエミッタの個数で決定される。図４には、集束作用があり放出電流の低下がないエミッタ群の総放出電流を１００％としたときの、引き出し電極（ゲート電極）の厚さとエミッタとの高さの比に対する総放出電流の関係を示したものである。
【００３１】
図３では、引き出し電極（ゲート電極）の厚さとエミッタとの高さの比が２以上でエミッタ１個当たりの放出電流を８０％以上を確保でき、さらに、引き出し電極（ゲート電極）の厚さとエミッタとの高さの比が４で集束電極を用いない時のエミッタ群の総放出電流と同レベルまで確保できることが分かった。さらに、図４で示されるようにエミッタ群としては少なくとも引き出し電極（ゲート電極）の厚さとエミッタとの高さの比が１以上であれば、従来と同程度あるいはそれ以上の総放出電流を得られることがわかる。
【００３２】
一方、総放出電流を向上させる方法として電極の材質や印加電圧を最適化する方法がある。例えば、文献”第７回真空マイクロエレクトロニクスに関する国際会議の論文集，７ｔｈＩｎｔｅｒｎａｔｉｏｎａｌＶａｃｕｕｍＭｉｃｒｏｅｌｅｃｔｒｏｎｉｃｓＣｏｎｆｅｒｅｎｃｅ１９９４Ｊｕｌｙｐ．４０５〜４０７”には、エミッタを陽極化成処理することにより、総放出電流が向上することが報告されている。即ち、総放出電流の低下分は電極の材質や印加電圧等の他のパラメータを適正化することで補填することが可能であり、図４において、少なくとも４０％であれば、総放出電流を１００％まで（２．５倍とする）補填することが可能である。即ち、引き出し電極（ゲート電極）の厚さとエミッタとの高さの比が０．５以上であれば、従来と同程度あるいはそれ以上の総放出電流を得ることが可能となる。
【００３３】
また、引き出し電極（ゲート電極）の厚さは厚い方がよいが、電極の厚膜化もプロセス上難しく、さらに図４で厚くすると総電流は下降する傾向にある。エミッタ高さが１μｍであれば１０倍の１０μｍ程度が限界であろう。さらに、電子源が薄型化され、エミッタが低くなると、図３での増加の傾きが緩やかとなり、図４においても増加の傾きが緩やかとなる。その場合、エミッタ高さに対して電極の厚さはさらに大きくする必要があり、その場合は１０倍以上の可能性もある。また、エミッタ高さが１μｍより１桁以上大となることは、電子源の薄型化に対して、またプロセス上困難であることから考慮しなくてもよい。
【００３４】
図５に、引き出し電極の膜厚を従来の膜厚の０．３μｍから３μｍ（この時エミッタの高さ１μｍ）に厚くした時のアノード電流の変化を調べた実験結果を示す。集束電極に印加する電圧を小さくしてもアノ−ド電流の低下は抑制され、電子源として十分な電流密度を確保することができた。また、従来の課題で説明した図３０と併せると、印加電圧を小さくして電子線を集束させ且つ電流密度の高い電子源を提供することができた。
【００３５】
なお、フィールドエミッタ１５の先端から放出された電子は集束電極１３の形成する電界により減速され、集束されて、電子源の外部に設けられた陽極方向へ放出される。
【００３６】
さらに、上記実施の形態では複数のエミッタを有する電子源について説明したが、エミッタ自身は１つで１つの電子源を構成してもよい。
【００３７】
実施の形態２．
この発明の実施の形態２を図について説明する。図６は実施の形態２による電子源の要部を示す断面図である。図において、従来と異なるのは引き出し電極１２と集束電極１３の間の第２絶縁膜１６の膜厚を十分厚くしている。
【００３８】
次に、このように構成されたものにおける電子源の動作について説明する。引き出し電極１２にカソード電極１１に対し、例えば＋６０〜＋１１０Ｖの電圧を印加する。また、集束電極１３にはカソード電極１１に対し、例えば０〜＋２０Ｖの電圧を印加する。この際に、エミッタ１５先端の電界を低下させる集束電極１３がエミッタ１５から離れるために、エミッタ１５先端への集束電極１３からの電界の影響が低減できる。
【００３９】
図７は、第２絶縁膜１６の厚さとエミッタ１５先端から放出される電流との関係を示す、差分法を用いた電界解析結果である。横軸は第２絶縁膜１６の厚さとエミッタ１５の高さの比で、縦軸はエミッタ１５先端から放出される電流を集束電極１３を用いない時の電流値を１００％として規格化したものである。図中Ｂ点は、集束電極１３を用い且つ、従来の膜厚条件（エミッタ高さ１μｍ、第２絶縁膜の厚さ１μｍ）での放出電流の比で、第２絶縁膜１６の厚さを厚くすることでエミッタ１５先端からの放出電流が増加することが分る。例えば、第２絶縁膜１６の厚さとエミッタ１５の高さの比が３以上で、従来１０％以下であった放出電流を３０％以上に確保できることがわかる。従って、実施の形態１と同様に集束電極に印加する電位を小さくして電子線を集束させても高電流密度の電子線を発生可能な電子源を提供することができる。
【００４０】
一方、第２絶縁膜を厚くすると、図６におけるエミッタ間のピッチｐが広がり、複数のエミッタを形成して電子源とする際の単位面積当たりのエミッタ数が減少する。そのため、複数のエミッタを形成して電子源として用いる場合、全てのエミッタからの放出電流の合計は、１個当たりのエミッタからの放出電流とエミッタの個数で決定される。図８には、集束作用があり放出電流の低下がないエミッタ群の総放出電流を１００％としたときの、第２絶縁膜の厚さとエミッタの高さとの比に対する総放出電流の関係を示したものである。図８で示されるようにエミッタ群としては少なくとも第２絶縁膜の厚さとエミッタの高さとの比が２．５以上であれば、エミッタ群としての総電流は４０％程度で飽和する。上記実施の形態１で述べたように、エミッタ群としての総電流は４０％程度であれば、他のパラメータを適正化することで、総電流を１００％まで補填することが可能である。従って第２絶縁膜の厚さは厚さはエミッタ高さが１μｍであれば、２．５μｍであればよい。なお、厚さの上限は厚膜化プロセスを考慮すると１０倍の１０μｍ程度であろう。
【００４１】
さらに、電子源が薄型化され、エミッタの高さが低くなると、図７での増加の傾きが緩やかとなり、図８においても増加の傾きが緩やかとなる。その場合、エミッタ高さに対して電極の厚さはさらに大きくする必要があり、その場合は１０倍以上の可能性もある。また、エミッタ高さが１μｍより１桁以上大となることは、電子源の薄型化に対して、またプロセス上困難であることから考慮しなくてもよい。エミッタ高さが１μｍより大きくなると図７、８共に傾きが急俊になりエミッタ高さに対する第２絶縁膜の厚さの比は２．５よりも小さくてよい。
【００４２】
なお、実施の形態１と同様に、エミッタ自身は１つで１個の電子源を構成してもよい。
【００４３】
実施の形態３．
この発明の実施の形態３を図について説明する。図９は実施の形態３による電子源の要部を示す断面図であり、図１０は電極の結線状態を示す概略平面図である。図において、１２ａは第２の引き出し電極であり、第１の引き出し電極１２と集束電極１３の間にそれぞれ第２絶縁膜１６、第３絶縁膜３６を介して設けた。さらに、図１０に示すように、第２の引き出し電極１２ａは１ヶ所より、第２の引き出し電極１２ａに給電する端子部を構成するボンディング端子（電極端子）１９ａへ接続する線状の配線２１ａが伸びて上部の空間に露出している。さらに、ボンディング端子１９ａには電圧を供給する導線２４ａが接続されている。
【００４４】
次に、このように構成されたものにおける電子源の動作について説明する。第１の引き出し電極１２にカソード電極１１に対し、例えば＋６０〜＋１１０Ｖの電圧を印加する。また、集束電極１３にはカソード電極１１に対し、例えば０〜＋２０Ｖの電圧を印加する。第２の引き出し電極１２ａには少なくとも集束電極１３より高く第１の引出し電極１２より低い電位、例えば＋５０Ｖを印加する。すると、エミッタ１５先端近傍の電界強度は、第２の引き出し電極１２ａが集束電極１３の電界強度の影響に対して遮蔽の役目を果たし、十分な電界強度が得られる。従って、実施の形態１、２と同様に集束電極に印加する電位を小さくして電子線を集束させても高電流密度の電子線を発生可能な電子源を提供することができる。このように、多層にすることで実施の形態１、２にように各層の厚さを従来と比べて極端に厚くする必要がないため、それぞれの膜を厚膜化することで生じる問題、例えば、膜内の内部応力等を無視することが可能となる。
【００４５】
実施の形態４．
この発明の実施の形態４を図について説明する。図１１は実施の形態４による電子源の要部を示す断面図であり、図１２は電極の結線状態を示す概略平面図である。実施の形態３では、第２の引き出し電極１２ａに印加する電位を第１の引き出し電極１２と集束電極１３とに印加する電位の中間的な電位としたが、本実施の形態４では外部回路で第１の引き出し電極１２と第２の引き出し電極１２ａとを導通させ、同電位とした。図１１において、導通部を構成する外部回路は各電極と同一基板上に形成されており、３８はボンディング端子部に設けられた電極端子であり、第１の引き出し電極１２と第２の引き出し電極１２ａを開口部１０の外部で電気的に短絡させている。
【００４６】
このように構成された電子源に対し、第１の引き出し電極１２および第２の引き出し電極１２ａにはカソード電極１１に対し、例えば＋６０〜＋１１０Ｖの電圧を印加し、集束電極１３にはカソード電極１１に対し、例えば０〜＋２０Ｖの電圧を印加する。
【００４７】
このような構成にすれば、実施の形態３と同様、各層の厚さを薄くすることができるので各膜を厚くすることで生じる問題、例えば膜内の内部応力や剥離等を無視することができる。また、図１２に示すように第１の引き出し電極１２と第２の引き出し電極１２ａの電極端子３８が共通となるので、電極端子数を減らすことができ、電極端子等からの非対称電界の影響を小さくすることができる。さらに、電源の数も少なくてすみ、簡便な構成で、高性能の電子源が得られる。
【００４８】
なお、図１１では第１の引き出し電極と第２の引き出し電極を、各電極と同一基板上に設けた外部回路において短絡させたが、電源と電極端子との間の外部回路（基板の外）で短絡させてもよい。このようにすれば電極端子数は減らないが製造が容易となる。
また、第１の引き出し電極と第２の引き出し電極を配線２１、２１ａを通さず、直接、電極内部で短絡させてもよい。このようにすれば配線２１、２１ａが一本となり、より簡便な構成となる。
【００４９】
なお、図１３はエミッタ高さに対する引き出し電極の膜厚の比とエミッタ先端の電界強度との関係を示したものであり、実施の形態１における引き出し電極のを２分して第１及び第２の引き出し電極とし、第２の引き出し電極を従来通りの厚さの第２絶縁膜の中間に設け（絶縁膜は図１１中の第２絶縁膜１６と第３絶縁膜３６に分離）、第１及び第２の引き出し電極に同電位を印加した時の本実施の形態の第２の引き出し電極を採用した３段電極（２段の引き出し電極と１段の集束電極）の効果を示したものである。エミッタ高さに対する引き出し電極の膜厚の比が２の時、実施の形態１と同程度の効果があることが確認された。ここで、３段電極においては引き出し電極の厚さとは、第１及び第２の引き出し電極の厚さと第２絶縁膜との和であるから、各層の厚さは実施の形態１と比べて小さくすることができる。また、第１及び第２の引き出し電極に印加する電位を調整すれば、第１及び第２の引き出し電極の厚さを厚くする必要はない。
【００５０】
実施の形態５．
この発明の実施の形態５を図について説明する。図１４は実施の形態５による電子源の要部を示す断面図である。図において、第２の引き出し電極１２ａを第１の引き出し電極１２と集束電極１３の間にそれぞれ絶縁膜１６、３６を介して設け、開口部１０の内壁で第１の引き出し電極１２及び第２の引き出し電極１２ａを接続させるための電極面３７を設けた。
【００５１】
このような構成にすれば、外部回路で第１の引き出し電極１２及び第２の引き出し電極１２ａを接続させる必要はなく、構造が簡単になる。さらに、引き出し電極に与える電位の影響を開口部の内部に形成される電界に与え易く、カソード電極先端の電界の低下を防止でき、電流密度が高く集束特性の優れた電子線が得られる。
【００５２】
実施の形態６．
この発明の実施の形態６を図について説明する。実施の形態６による電子源の構造は図９及び図１０に示した実施の形態３のものと同様であるが、各電極に印加される電圧が異なる。
【００５３】
この電子源の動作について説明する。図９において、第１の引き出し電極１２にはカソード電極１１に対し、例えば＋６０〜＋１１０Ｖの電圧を印加する。第２の引き出し電極１２ａには第１の引き出し電極１２より高い電圧、例えばカソード電極１１に対し＋８０〜＋１６０Ｖを印加する。また、集束電極１３にはカソード電極１１に対し、例えば＋２０〜＋８０Ｖを印加する。この際に、エミッタ１５先端の電界を低下させる集束電極１３からの電界の影響を第２の引き出し電極１２ａに印加した電圧により遮蔽することができ、集束電極１３自体もエミッタ１５から離れるためにエミッタ１５先端への集束電極１３からの電界の影響も低減できる。エミッタ１５には第１の引き出し電極１２に印加した電圧により電子放出に必要となる電界が生じるので電子が放出される。この方法を用いることでエミッタ１５の先端から放出された電子は集束電極１３の形成する電界により減速され、集束されて、電子源の外に設けられた陽極へ向けて放出される。
【００５４】
このように、第１の引き出し電極１２に与える電圧より第２の引き出し電極１２ａに与える電圧を高くすることにより、第２絶縁膜１６を上記実施の形態３〜５のものより薄くして全体の膜厚を薄くし、第１の引き出し電極と第２の引き出し電極の間の距離を小さくしても、第１の引き出し電極と第２の引き出し電極を同電位としたものと同じように電子線を集束する効果が得られる。また、集束電極に加える電圧がカソード電極に対し高くなることにより、カソード電極先端の電界の低下の影響が小さくなる。
【００５５】
実施の形態７．
この発明の実施の形態７を図について説明する。図１５は実施の形態７による電子源の要部を示す断面図であり、図１６は電極の結線状態を示す概略平面図である。図において、前記実施の形態３〜６の３段電極型と異なるのは第２の引き出し電極１２ａと集束電極１３を同一平面内に形成し、第３絶縁膜を無くして２層電極型にしたことにある。
【００５６】
次に、このように構成されたものにおける電子源の動作について説明する。第１の引き出し電極１２にカソード電極１１に対し、例えば＋６０〜＋１１０Ｖの電圧を印加する。また、集束電極１３にはカソード電極１１に対し、例えば０〜＋２０Ｖの電圧を印加する。第２の引き出し電極１２ａには少なくとも集束電極１３より高く第１の引出し電極１２より低い電位、例えば＋５０Ｖを印加する。すると、エミッタ１５先端近傍の電界強度は、第２の引き出し電極１２ａが集束電極１３の電界強度の影響に対して遮蔽の役目を果たし、十分な電界強度が得られる。従って、実施の形態３と同様に集束電極に印加する電位を小さくして電子線を集束させても高電流密度の電子線を発生可能な電子源を提供することができる。
【００５７】
このような構成にすれば、前記各実施の形態に比べて全膜厚を薄くすることができ、かつ各層の厚さを薄くすることができるので、全膜厚を厚くすることおよび各膜を厚くすることで生じる問題、例えば膜内の内部応力や剥離等を無視することができ、製造も容易となる。また、第２の引き出し電極１２ａと集束電極１３の形状を同時に作成することになるので、従来の３段電極型と比べて製造工程数を削減することができる。以上の２点により製造コスト低減、歩留まり向上等が実現できる。
【００５８】
なお、本実施の形態では第１の引き出し電極１２に与える電圧より第２の引き出し電極１２ａに与える電圧を低くしたが、実施の形態４と同様に、外部回路により第１の引き出し電極１２と第２の引き出し電極１２ａを短絡させ、例えば第１の引き出し電極１２および第２の引き出し電極１２ａにはカソード電極１１に対し＋６０〜＋１１０Ｖの電圧を、集束電極１３にはカソード電極１１に対し０〜＋２０Ｖの電圧を印加することにより、簡便な構成で、高性能の電子源が得られる。
【００５９】
さらに、図１５において、実施の形態６と同様に、例えば、第１の引き出し電極１２にはカソード電極１１に対し＋６０〜＋１１０Ｖの電圧を、第２の引き出し電極１２ａにはカソード電極１１に対し＋８０〜＋１６０Ｖを、集束電極１３にはカソード電極１１に対し＋２０〜＋８０Ｖを印加して、第１の引き出し電極１２に与える電圧より第２の引き出し電極１２ａに与える電圧を高くすることにより、第２絶縁膜１６がより薄くでき、全体の膜厚をより薄くすることができる。
【００６０】
実施の形態８．
この発明の実施の形態を図について説明する。図１７は実施の形態８による電子源の要部を示す断面図であり、図１８は電極の結線状態を示す概略平面図である。図において、実施の形態７と異なるのは第２の引き出し電極１２ａとボンディング端子１９ａを接続する線状の配線２１ａの仕方が異なる。すなわち、図１６に示すような配線パターンによって第２の引き出し電極１２ａ及び集束電極１３と同一平面上に配線２１ａを形成するのではなく、図１７に示すように第２の引き出し電極１２ａと集束電極１３とは別の平面に絶縁層３５を介して配線２１ａを形成したことにある。
【００６１】
このようにすることにより、集束電極１３が配線２１ａにより分断されることがないので、集束電極１３による電界の対称性が保たれ、集束特性の優れた電子線を発する電子源が得られる。
【００６２】
実施の形態９．
この発明の実施の形態９を図について説明する。図１９は実施の形態９による電子源の要部を示す断面図であり、図２０は電極の結線状態を示す概略平面図である。本実施の形態は実施の形態７と同様、２層電極型であるが、図１５に示す実施の形態７と異なるのは、第１の引き出し電極１２と第２の引き出し電極１２ａを開口部１０の内側で電極面３７により電気的に接続し、同電位としたことにある。
【００６３】
このような構成にすれば集束電極１３に与えた電位による電子放出部先端の電界の低下を、第１の引き出し電極１２と第２の引き出し電極１２ａによる電位により容易に遮蔽することができる。さらに、外部回路で第１の引き出し電極１２と第２の引き出し電極１２ａを接続させる必要はなく、構造が簡単になり、且つ集束電極１３による電界の対称性も保たれ、集束特性の優れた電子線を発する電子源が得られる。
【００６４】
実施の形態１０．
この発明の実施の形態１０を図について説明する。図２１は実施の形態１、２のように従来よりも各層の厚さを厚くして電子源を製造する時のプロセスを示したものである。図において、蒸着法により引き出し電極１２や絶縁膜１６、１７を成膜する場合に開口部１０形成用の円形マスク２９の厚さを所定の厚さに設定した場合の製造プロセスの様子を示している。
【００６５】
図中（ａ）において、例えばガラス材からなる基板１４上のエミッタ材（例えばＳｉ）２８の上に従来より厚く所定の厚さに設計された円形マスク材（例えばＳｉＯ２）３０を成膜する。次に（ｂ）においてエミッタ１５成形用に円形マスク材３０を円形に加工して円形マスク２９を作製する。（ｃ）において円形マスク２９を用いてエミッタ材２８を所望の形状のエミッタ１５に加工する。（ｄ）において、円形マスク２９及び基板１４のエミッタ１５の形成されていない部分に同時に第１絶縁膜（例えばＳｉＯ２）１７、引き出し電極（例えばＮｂ、Ａｕ、Ｐｔ等の金属、Ａｕであれば外部端子との接続が良好である）１２、第２絶縁膜（例えばＳｉＯ２）１６、集束電極（例えばＮｂ、Ａｕ、Ｐｔ等の金属、Ａｕであれば外部端子との接続が良好である）１３を順に、蒸着法により形成する。この際に円形マスク２９の保護によりエミッタ１５に絶縁材や電極材が付着しない。（ｅ）において円形マスク２９と円形マスク上の不要蒸着物３１をエッチング（例えばフッ酸溶液を用いる）により除去する。
【００６６】
次に、円形マスクの厚さの設計方法について説明する。図２２は円形マスクの厚さの違いによる電子源の形成の差を示したものである。図において、（ａ）は円形マスクの厚さを適正化しないで成膜した場合の状態を、（ｂ）は円形マスクの厚さを適正化して成膜した場合の状態を示したものである。図において、ｄｅはエミッタの高さ、ｄｍはマスクの厚さ、ｄは図２１の（ｄ）において成膜する場合の成膜中の膜（種類は問わない）の基板１４からの厚さ、ｒｏ及びｒｉはそれぞれｄの高さにおける開口部１０の径及びマスク２９上の蒸着物の径、ｒは基板上での開口径を示す。成膜中基板１４上の膜は開口部が広がるように成膜されていき、円形マスク２９上の膜はマスクの径から広がるように成膜されていく。このとき、円形マスク２９上の膜のマスクの径からの広がりが、基板１４上の膜の広がりより大きいため、円形マスクを十分厚くしておかないと、図中（ａ）のように、成膜が完了しないうちに開口部がふさがれてしまい、図２１の工程（ｅ）で、不要蒸着物の除去が難しく電子源を作製することができなかった。そこで、図２２中（ｂ）のように円形マスクの厚さを十分厚くすればよい。
【００６７】
次に、円形マスクの厚さの具体的な設定方法について説明する。図２３は、基板からの高さｄにおける開口部１０の径ｒｏ及びマスク２９上の蒸着物の径ｒｉの関係を示したグラフである。従来のエミッタの高さは１μｍ、マスクｄｍ１は０．３μｍ、基板上での開口径１．８μｍにおいて、ｒｏとｒｉの交点は約３．２μｍである。第１絶縁膜１７は約１μｍ、引き出し電極１２は０．３μｍ、第２絶縁膜１６は約１μｍ、集束電極１３は０．３μｍで膜厚の合計は２．６μｍであるので、開口部を塞ぐことなく十分電子源の製作が可能である。一方、実施の形態２のように絶縁膜を設計すると、例えば第２絶縁膜１６を３μｍとすると膜厚の合計は４．６μｍとなる。円形マスクの厚さを厚くしないと、電子源の製作はできない。そこで、図２３よりｄが４．６μｍ以上でｒｏとｒｉが交点を有するようにｒｉをｄ方向に平行移動させる。その時のｄｍ２が設計マスク厚となる。本実施の形態ではマスクの厚さを１μｍ以上とすれば、開口部が塞がれることなく、電子源の製作が可能となることがわかる。
【００６８】
また、実施の形態１で引き出し電極を３μｍとすると、膜厚の合計は５．３μｍとなる。このとき、グラフを外挿すると円形マスクの厚さは１．４μｍ以上必要であることがわかる。
【００６９】
なお、本グラフの傾きは蒸着装置の種類等により若干異なるが、予めｒｏとｒｉの関係を求めておけば、異なる装置を使用しても同様な手法で最適な円形マスクの厚さを設計することができる。
【００７０】
なお、上記実施の形態１〜１０では基板１４上にエミッタ１５を形成していたが、１枚のＳｉ基板を用い、これを加工してエミッタと基板を一体化させた構造であってもよい。
【００７１】
実施の形態１１．
この発明の実施の形態１１を図について説明する。図２４は例えば実施の形態１０および実施の形態１１による製造方法により製造された電子源を示す断面図である。実施の形態１０のようにして形成された電子源（図２４（ａ））においては、引き出し電極１２の膜厚が従来の引き出し電極の膜厚より厚いため、成膜時における膜の回り込みやエッチングの影響等により段状になったり、この段の角部が尖った形状に成り易く、エミッタ１５と引き出し電極１２の間で異常放電が生じたり、電極間が短絡することによる初期不良が発生することがあった。本実施の形態においてはこれを防ぐために、実施の形態１０の製造方法に加え、さらにウェットエッチング工程を施すものである。
【００７２】
例えば、引き出し電極１２、集束電極１３、基板１４、エミッタ１５、第１絶縁膜１７、第２絶縁膜１６をそれぞれＡｕ、Ｎｂ、Ｓｉ、Ｓｉ、ＳｉＯ_２、ＳｉＯ_２で作成する。形成後に例えば王水等で引き出し電極１２のＡｕのみわずかにウェットエッチングして開口部における引き出し電極１２の角部４０を、エミッタ１５に対して平坦面４１となるようにし、尖った部分を無くし、引き出し電極形状に丸みを帯びさせて図２４（ｂ）の様な形状にさせる。
【００７３】
このように尖りを無くし、丸みを帯びた形状にすることによりエミッタ１５から電子を放出させるために引き出し電極１２に電圧を印加したときに、エミッタ１５と引き出し電極１２の間での異常放電が生じにくくなる。
また、引き出し電極とカソード電極間に成膜時の回り込みによるＡｕの異物が存在し、それを介して電極間が短絡することによる初期不良が発生することがあるが、ウェットエッチングにより尖った部分とともに異物を除去することで初期不良を低減することができ、歩留まりが向上する。
【００７４】
実施の形態１２．
この発明の実施の形態１２を図について説明する。図２５は、実施の形態１〜１１のいずれかに記載の電子源を用いた陰極線管の断面構成図である。図において、１つのあるいは複数のエミッタから構成される電子源５１から出射された電子線５３は、電子線の集束手段である電子銃５２内でクロスオーバー点５９を形成して偏向磁石５４で偏向され、シャドウマスク５５を介してアルミ膜５７を有する蛍光体５６の所望の位置に導かれる。陰極線管を構成するものは真空容器５８内に収納されている。
【００７５】
このように、実施の形態１〜１１のいずれかの電子源を陰極線管に用いると電子源から出射された電子線が既に集束しているため、十分に集束された電子線が得られ、陰極線管としての解像度が向上する。
【００７６】
実施の形態１３．
この発明の別の実施の形態を図について説明する。図２６は、実施の形態１〜１１のいずれかに記載の電子源を用いた陰極線管の断面構成図である。図において、電子源５１は３つの電子源５１Ｒ、５１Ｇ、５１Ｂに分別され、それぞれの電子源から出射された電子線は、電子線の集束手段である電子銃５２内でクロスオーバー点５９（それぞれ５９Ｒ、５９Ｇ、５９Ｂ）を形成して偏向磁石５４で偏向され、シャドウマスク５５を介してアルミ膜５７を有する蛍光体５６のそれぞれ赤の蛍光体部分、緑の蛍光体部分、青の蛍光体部分に導かれる。なお、本装置も真空容器内に収納されている。
【００７７】
このように、実施の形態１〜１１のいずれかの電子源を陰極線管に用いると電子源から出射された電子線が既に集束しているため、十分に集束された電子線が得られ、陰極線管としての解像度が向上し、本実施の形態ではカラー画像としての品質も向上し、性能の高い陰極線管を提供することが可能となる。
【００７８】
なお、実施の形態１２、１３の電子銃内でのクロスオーバー点は十分な集束が可能であれば、形成されなくてもよい。
【００８１】
【発明の効果】
以上のように、この発明によれば、カソード電極の略円錐形状の電子放出部の高さに対する引き出し電極の厚さの比を０．５以上としたので、従来より引き出し電極が厚く集束電極と電子放出部との距離が確保でき、且つ引き出し電極の厚さが十分厚いため、電子放出部即ちカソード電極先端の電界の低下が防止でき、引き出し電極の電位を電子放出部に与え易くなり、電流密度が高く集束特性の優れた電子線を発する電子源を提供することができる。
【００８２】
また、前記電子源において、カソード電極の略円錐形状の電子放出部の高さに対する引き出し電極の厚さの比を１以上としたので、従来より引き出し電極が厚く集束電極と電子放出部との距離が確保でき、且つ引き出し電極の厚さが十分厚いため、電子放出部即ちカソード電極先端の電界の低下が防止でき、引き出し電極の電位を電子放出部に与え易くなり、電流密度が高く集束特性の優れた電子線を発する電子源を提供することができる。さらに、エミッタ群を形成した時に、他のパラメータを操作することなく、総電流量を集束作用があり放出電流の低下がないエミッタ群と同レベルに確保でき、高性能な電子源を提供することができる。
【００８４】
また、カソード電極の略円錐形状の電子放出部の高さに対する第２の絶縁層の厚さの比を２．５以上としたので、従来より引き出し電極が厚く集束電極と電子放出部との距離が確保され、電子放出部即ちカソード電極先端の電界の低下が防止でき、所定の引き出し電位で電子放出を容易に制御することができ、電流密度が高く集束特性の優れた電子線を発する電子源を提供することができる。
【００８５】
また、集束電極と引き出し電極（第１の引き出し電極）の間に第２の引き出し電極を備え、引き出し電極（第１の引き出し電極）と第２の引き出し電極とを同電位とし、引き出し電極（第１の引き出し電極）と第２の引き出し電極とを開口部の内面で接続したので、厚い引き出し電極を用いた場合と同様に集束電極と電子放出部との距離が確保でき、且つ第１の引き出し電極と第２の引き出し電極とで形成される実効的な引き出し電極の厚さが十分厚く、また、引き出し電極に与える電位の影響を開口部の内部に形成される電界に与え易く、電子放出部即ちカソード電極先端の電界の低下を防止でき、電流密度が高く集束特性の優れた電子線を発する電子源を提供することができる。さらに、１つの電極の厚さを厚くする必要がないため、製造プロセスが容易となり、歩留りも向上する。
【００８６】
また、集束電極と同一平面上で、かつ前記集束電極の開口部側に第２の引き出し電極を備えたので、電子放出部即ちカソード電極先端の電界の低下を防止でき、電流密度が高く集束特性の優れた電子線を発する電子源を提供することができる。さらに、全膜厚を薄くすることができ、製造が容易となり、製造コスト低減、歩留まり向上等が実現できる。
【００８７】
また、前記電子源において、引き出し電極（第１の引き出し電極）と第２の引き出し電極とを同電位としたので、厚い引き出し電極を用いた場合と同様に集束電極と電子放出部との距離が確保でき、且つ第１の引き出し電極と第２の引き出し電極とで形成される実効的な引き出し電極の厚さが十分厚いため、電子放出部即ちカソード電極先端の電界の低下を防止でき、引き出し電極の電位を電子放出部に与え易くなり、電流密度が高く集束特性の優れた電子線を発する電子源を提供することができる。さらに、１つの電極の厚さを厚くする必要がないため、製造プロセスが容易となり、歩留りも向上する。
【００８８】
また、前記電子源において、引き出し電極（第１の引き出し電極）と第２の引き出し電極とを開口部の内面で接続したので、引き出し電極に与える電位の影響を開口部の内部に形成される電界に与え易く、電子放出部即ちカソード電極先端の電界の低下を防止でき、電流密度が高く集束特性の優れた電子線を発する電子源を提供することができる。
【００８９】
また、前記電子源において、引き出し電極（第１の引き出し電極）と第２の引き出し電極とを開口部の外部で接続したので、電流密度が高く集束特性の優れた電子線を発する電子源を容易に製造することができる。
【００９０】
また、前記電子源において、第２の引き出し電極に印加する電位を引き出し電極（第１の引き出し電極）に印加する電位より高くしたので、全体の膜厚を薄くし、第１の引き出し電極と第２の引き出し電極の間の距離を小さくしても、第１の引き出し電極と第２の引き出し電極を同電位としたものと同じように電子線を集束する効果が得られ、高性能な電子源を提供することができる。また、膜厚が薄くできることから、製造プロセスが容易となり、歩留まりも向上する。
【００９１】
また、陰極線管において、前記電子源のいずれか１つの電子源を搭載したので、元々集束性が高く、高電流密度の電子線を電子源から発することができるため、制御性の高い陰極線管を構成することができ、高性能な陰極線管を提供することができる。
【図面の簡単な説明】
【図１】実施の形態１による電子源の要部の構成を示す断面図である。
【図２】実施の形態１による電子源の電極の結線状態を示す概略平面図である。
【図３】引き出し電極の厚さと放出電流の関係を示す電界解析結果のグラフである。
【図４】引き出し電極の厚さと総放出電流の関係を示す電界解析結果のグラフである。
【図５】引き出し電極の厚さを変化させた時の集束電極への印加電圧とアノード電流の関係を示すグラフである。
【図６】実施の形態２による電子源の要部の構成を示す断面図である。
【図７】第２絶縁膜の厚さと放出電流の関係を示す電界解析結果のグラフである。
【図８】第２絶縁膜の厚さと総放出電流の関係を示す電界解析結果のグラフである。
【図９】実施の形態３による電子源の要部の構成を示す断面図である。
【図１０】実施の形態３による電子源の電極の結線状態を示す概略平面図である。
【図１１】実施の形態４による電子源の要部の構成を示す断面図である。
【図１２】実施の形態４による電子源の電極の結線状態を示す概略平面図である。
【図１３】３段電極構造（第２の引き出し電極有り）の効果を示すグラフである。
【図１４】実施の形態５による電子源の要部の構成を示す断面図である。
【図１５】実施の形態７による電子源の要部の構成を示す断面図である。
【図１６】実施の形態７による電子源の電極の結線状態を示す概略平面図である。
【図１７】実施の形態８による電子源の要部の構成を示す断面図である。
【図１８】実施の形態８による電子源の電極の結線状態を示す概略平面図である。
【図１９】実施の形態９による電子源の要部の構成を示す断面図である。
【図２０】実施の形態９による電子源の電極の結線状態を示す概略平面図である。
【図２１】実施の形態１０による電子源の製造プロセスを示す断面図である。
【図２２】マスク厚さの違いによる電子源の製造の良否を示す模式図である。
【図２３】マスク厚さを決定するための、マスク上の蒸着物の径と基板上の蒸着物の内径との関係を示すグラフである。
【図２４】実施の形態１０および実施の形態１１による電子源の製造方法により製造された電子源を示す断面図である。
【図２５】実施の形態１〜１１のいずれかによる電子源を搭載した陰極線管の断面構成図である。
【図２６】実施の形態１〜１１のいずれかによる電子源を複数搭載した陰極線管の断面構成図である。
【図２７】従来の電子源を示す断面構成図である。
【図２８】従来の電子源の製造プロセスを示す断面図である。
【図２９】従来の陰極線管を示す断面構成図である。
【図３０】従来の電子源の集束電極への印加電圧とアノード電流、電子ビーム発散角の関係を示すグラフである。
【符号の説明】
１０開口、１１カソード電極、
１２引き出し電極（第１の引き出し電極）、１２ａ第２の引き出し電極、
１３集束電極、１４基板、１５エミッタ、
１６第２絶縁膜、１７第１絶縁膜、１８電極端子、
１９電極端子、１９ａ電極端子、２０配線、２１配線、
２１ａ配線、２２配線、２３電極端子、２４導線、
２４ａ導線、２５導線、２６導線、２８エミッタ材、
２９円形マスク、３０円形マスク材、３１不要蒸着物、
３５絶縁層、３６第３絶縁膜、３７開口部内壁の電極面、
３８電極端子、５１、５１Ｒ、５１Ｇ、５１Ｂ電子源、
５２電子銃、５３電子線、５４偏向磁石、５５シャドウマスク、
５６蛍光体、５７アルミ膜、５８真空容器、
５９、５９Ｒ、５９Ｇ、５９Ｂクロスオーバー点、
１００電子線、１０１カソード電極（基板）、１０１ａ酸化膜、
１０２引き出し電極、１０３集束電極、１０４エミッタ、
１０５絶縁膜、１０６絶縁膜、１０７第３絶縁膜、
１０８加速電極、１０９引き出し電極用電源、
１１０集束電極用電源、１１１加速電極用電源、
１１２マスク、１１３ａ、１１３ｂフォトレジスト、
１２１フィールドエミッタからなるカソード、
１２２アノード電極、１２３アノード電極、１２４電子レンズ、
１２５電子レンズ、１２６コンバージェンス電極、
１２７クロスオーバー点、１２８偏向マグネット、
１２９シャドウマスク、１３０アルミ膜、
１３１アルミバックつき蛍光体。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a field emission type electron source used in a CRT type display, a vacuum tube, a semiconductor manufacturing apparatus or the like.as well asCathode ray using itOn the tubeIt is related.
[0002]
[Prior art]
Conventionally, an electron source using thermionic emission from a hot filament has been widely used. However, as an image display device becomes thinner and lighter, a field emission type using a semiconductor microfabrication technology ( The development of field emitters has attracted attention.
[0003]
FIG. 27 is a cross-sectional view showing a part of the structure of a conventional field emission electron source described in, for example, Japanese Patent Laid-Open No. 2-226635. In the figure, an emitter 104 forming an electron emitting portion is formed in a conical shape by processing a substrate 101 which is a cathode electrode. An insulating film 105, an extraction electrode 102, an insulating film 106, a focusing electrode 103, an insulating film 107, and an acceleration electrode 108 are sequentially stacked on the substrate 101 so as to surround the emitter 104. Electrons are extracted from the tip of the emitter 104 by the voltage applied between the extraction electrode 102 and the substrate 101 (voltage from the power source 109), and the electrons are focused by the voltage applied to the focusing electrode 103 by the power source 110. Electrons are accelerated by the voltage applied to the acceleration electrode 108 by 111 and emitted as an electron beam 100. In this embodiment, the electrode has a three-layer structure of an extraction electrode, a focusing electrode, and an acceleration electrode, and different potentials are applied to each other. However, as long as the extraction electrode is present, electron emission is realized.
[0004]
Next, the operation of the electron source will be described. When a positive voltage of, for example, 100 V is applied to the extraction electrode 102 from the power source 109 to the cathode electrode (substrate) 101, about 10⁷An electric field of V / cm is generated, and electrons are emitted from the emitter 104 by the tunnel effect. The magnitude of the current due to the emitted electrons is 25 to 100 μA per emitter, and a high current density can be obtained depending on the density of the emitter 104. Moreover, since almost no current flows through the extraction electrode 102, the power consumption is extremely small.
[0005]
By the way, in the field emission electron source as described above, the emitted electron beam 100 diverges due to the influence of the electric field distribution reflecting the shape of the tip of the emitter 104. Therefore, the focusing electrode 103 is designed to focus the emitted electron beam 100 by applying a potential similar to that of the cathode electrode 101 to the focusing electrode 103 by decelerating the emitted electrons. This is accelerated and released by the acceleration electrode 108 to which a positive potential is applied by the power source 111. However, electrons can be accelerated by an external anode without providing the acceleration electrode 108 for each emitter.
[0006]
Using such photoengraving and thin film technology, such an element can simultaneously produce about one million emitter arrays at intervals of several μm to 10 μm, and an electron source with a peak current of 100 A can be obtained. In addition, the electron source has a low emittance with no power loss other than power consumption due to the emission current flowing through the cathode electrode 101 and no electron beam divergence.
[0007]
Next, a method for forming such a conventional field emission electron source will be described. As for the method of forming a field emission electron source, for example, the magazine “1990 Annual Meeting of the Institute of Electronics, Information and Communication Engineers (1990) p. 5-282” and “The 7th International Conference on Vacuum Microelectronics, 7th” International Vacuum Microelectronics Conference 1994 Jul. P. 25-28 ". 28 is a cross-sectional process diagram illustrating a method for forming a field-emission electron source described in “The 7th International Vacuum Microelectronics Conference 1994 July p. 25-28”, the 7th International Conference on Vacuum Microelectronics, 7th International Vacuum Microelectronics Conference. In the figure, (a) to (f) indicate the order of steps. First, a photoresist 113a is used on a semiconductor substrate 101 such as Si (or a conductor such as Al) substrate 101 to form SiO.₂The circular mask 112 is formed (step (a)). The Si substrate 101 is isotropically etched using the mask 112, and then the substrate surface is thermally oxidized. As a result, an oxide film 101a is formed along the surface of the substrate 101 in (b) in the figure (step (b)). Next, SiO₂The insulating layer 105 and the electrode 102 made of Nb, for example, are formed (step (c)). The electrode 102 is further provided with a photoresist 113b to provide a connection terminal portion (step (d)), and SiO 2₂An insulating layer 106 and an electrode 103 made of Nb, for example, are formed (step (e)). Finally, the photoresist 113b is removed, and SiO₂When the circular mask 112 is removed with hydrofluoric acid, a part of the oxide film 101a on the substrate 101 is also removed, and a sharp conical emitter 104 having a tip shape as shown in FIG.
[0008]
As an example, the opening diameter of the electron emission portion where the emitter 104 is located is 2 to 3 μm, the height of the cone is 1 μm, and the tip diameter of the cone is 0.06 μm. The thickness of the electrodes 102 and 103 is usually about 0.1 to 0.3 μm because it is not necessary to increase the thickness as long as the voltage can be applied. In addition, the insulating layer 105 is set to be approximately the same as the height of the emitter (1 μm) in order to efficiently emit electrons from the tip of the emitter 104, and the thickness of the insulating layer 106 is also a dielectric strength voltage between the electrode 102 and the electrode 103. In consideration of the above, it is usually set to 1 μm which is the same as that of the insulating layer 105.
[0009]
As an application example of the electron source as described above, a CRT electron gun can be considered. An example in which this type of electron source is applied to a CRT is described in JP-A-48-90467. However, as the electron source, a configuration in which the focusing electrode 103 is provided in addition to the extraction electrode 102 in each emitter 104 is not described. FIG. 29 shows the configuration of the electron gun. In the figure, an electron beam emitted from an electron source (an electron source consisting of a field emitter) 121 passes through a first anode electrode 122 and a second anode electrode 123 for acceleration, and is crossed by a crossover point 127 by electron lenses 124 and 125. , And is focused by the convergence electrode 126, further controlled in direction by the deflection magnet 128, and then focused on the phosphor screen of the phosphor 131 with the aluminum back 130 through the shadow mask 129.
[0010]
On the other hand, as an invention relating to a field emitter type electron source, the applicant disclosed in Japanese Patent Laid-Open No. 5-198278 a flat panel using an electron source that can easily address a two-dimensional pixel with a simple element configuration and is easy to manufacture. An invention for a type display has already been filed. Further, Japanese Patent Application No. 6-240169 has already filed an invention in which a field emission electron source in which a shielding electrode is arranged opposite to a focusing electrode is applied to a cathode ray tube in order to improve focusing characteristics of the electron source.
[0011]
[Problems to be solved by the invention]
Since the conventional field emission type electron source is configured as described above, it is necessary to apply a desired potential to the focusing electrode 103 in order to obtain an electron beam with excellent focusing characteristics. When applying a higher potential than the extraction electrode as a method of applying a potential, a high voltage on the order of several kV is required, and it is necessary to increase the insulation layer between the extraction electrode and the focusing electrode to a dielectric breakdown voltage, and the power consumption increases. There was a problem. Therefore, the potential applied to the focusing electrode is lower than the extraction electrode, for example, the focusing electrode 0V is applied to the extraction electrode 100V. However, if the potential of the focusing electrode is lower than the potential applied to the extraction electrode, there is a problem that the electric field at the tip of the emitter is lowered due to the potential applied to the focusing electrode, and the electrons emitted by the tunnel effect are extremely reduced. occured. FIG. 30 shows the experimental results of examining changes in the anodic current and the divergence angle of the electron beam with respect to the potential applied to the focusing electrode. The figure shows the normalized value with the value of the voltage of the focusing electrode at 100V. The higher the voltage applied to the focusing electrode, the larger the anode current, that is, sufficient electron beam intensity is obtained, while the electron beam diverges. When the voltage applied to the focusing electrode is reduced, the electron beam is focused, but the current value is drastically reduced.
[0012]
The present invention has been made in order to solve the above-described problems. The anode current does not decrease even when the voltage applied to the focusing electrode is reduced. The purpose is to provide an electron source. That is, the structure of an electron source is provided so that the voltage applied to the focusing electrode does not affect the emitter, and a cathode ray tube equipped with the high-performance electron source is provided.Rukoaimed to.
[0015]
[Means for Solving the Problems]
The electron source according to the present invention draws electrons from the first insulating layer and the cathode electrode portion in order so as to surround the electron emission portion by forming an opening on the cathode electrode having a substantially conical electron emission portion. And an extraction electrode, a second insulating layer, and a focusing electrode for focusing the extracted electrons are arranged to shield the influence of the electric field formed by the potential applied to the focusing electrode on the electron emission portion of the cathode electrode. With means to,Means for shielding the influence of the electric field formed by the electric potential applied to the focusing electrode on the electron emission portion of the cathode electrodeHowever, the ratio of the thickness of the extraction electrode to the height of the substantially conical electron emission portion of the cathode electrode is that the extraction electrode has a thickness of 0.5 or more.
[0016]
Also,Means for shielding the influence of the electric field formed by the potential applied to the focusing electrode on the electron emission portion of the cathode electrodeHowever, the ratio of the thickness of the extraction electrode to the height of the substantially conical electron emission portion of the cathode electrode defines that the extraction electrode has a thickness of 1 or more.
[0018]
Also,Means for shielding the influence of the electric field formed by the potential applied to the focusing electrode on the electron emission portion of the cathode electrodeHowever, the ratio of the thickness of the second insulating layer to the height of the substantially conical electron emission portion of the cathode electrode is defined as the second insulating layer having a thickness of 2.5 or more.
[0019]
The means for shielding the influence of the electric field formed by the potential applied to the focusing electrode on the electron emission portion of the cathode electrode is a second extraction electrode between the focusing electrode and the extraction electrode (first extraction electrode). WithThe extraction electrode (first extraction electrode) and the second extraction electrode are set to the same potential, and the extraction electrode (first extraction electrode) and the second extraction electrode are connected to each other at the inner surface of the opening.It is stipulated that it is.
[0020]
The means for shielding the influence of the electric field formed by the potential applied to the focusing electrode on the electron emission portion of the cathode electrode is on the same plane as the focusing electrode and on the opening side of the focusing electrode. It is defined that a lead electrode is provided.
[0021]
In addition, it defines that the extraction electrode (first extraction electrode) and the second extraction electrode have the same potential.
[0022]
Further, it is defined that the extraction electrode (first extraction electrode) and the second extraction electrode are connected by the inner surface of the opening.
[0023]
Further, it defines that the extraction electrode (first extraction electrode) and the second extraction electrode are connected outside the opening.
[0024]
In addition, it defines that the potential applied to the second extraction electrode is higher than the potential applied to the extraction electrode (first extraction electrode).
[0025]
In addition, a cathode ray tube according to the present invention includes an electron source having any of the above-described configurations, a means for focusing an electron beam emitted from the electron source, and a focused electron beam in a predetermined phosphor of a phosphor. And a means for deflecting and guiding to the position.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1 FIG.
Embodiment 1 of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing a main part of an electron source according to Embodiment 1, and FIG. 2 is a schematic plan view showing a connection state of electrodes. In the figure, a silicon substrate constituting the cathode electrode 11 is fixed on a substrate 14 made of, for example, a glass material, and this surface is processed to obtain a conical field emitter 15. The electron source is formed on a substrate 14 around the opening 10 having the emitter, and a focusing electrode 12 is formed to apply an electric field to the field emitter 15 to extract the electrons and to form an electron lens for aligning the directions of the extracted electrons. The electrodes 13 are stacked via the first insulating film 17 and the second insulating film 16, respectively. The openings 10 and the field emitters 15 are arranged in a region having a diameter of 200 μm at a pitch of 7.5 μm, for example, and the number thereof is 600 or more although omitted in the drawing. As shown in FIG. 1, the tip of the field emitter 15 is substantially at the same height as the lower surface of the extraction electrode 12.
[0028]
Further, as shown in FIG. 2, the focusing electrode 13 is formed to have a circular shape having a diameter of 400 μm with an opening 10 at the center, that is, an electron emission region, when viewed from above. However, the linear wiring 22 connected to the bonding terminal (electrode terminal) 23 extends and is exposed in the upper space. Similarly, the bonding terminals (electrode terminals) 19 and 18 of the lead electrode 12 and the cathode electrode 11 are also exposed in the space, and the linear wirings 21 and 20 that connect the terminals 19 and 18 to the electrodes are also drawn in the lead electrode 12, It extends to the outside of the cathode electrode 11. Further, conducting wires 26, 24, and 25 for supplying voltage are connected to the bonding terminals 18, 19, and 23, respectively. Thus, the bonding terminals 18, 19, and 23, the wirings 20, 21, and 22 and the conductive wires 26, 24, and 25 that constitute the terminal portions for supplying power to the electrodes 11, 12, and 13 are partially exposed to the electron emission space side. doing.
[0029]
Next, the operation of this electron source will be described. A voltage of +60 to +110 V is applied to the extraction electrode 12 with respect to the cathode electrode 11. In addition, a voltage of 0 to +20 V is applied to the focusing electrode 13 with respect to the cathode electrode 11. At this time, since the extraction electrode 12 is sufficiently thick, the influence of the electric field from the focusing electrode 13 that lowers the electric field at the tip of the emitter 15 can be shielded, and the influence of the electric field from the focusing electrode 13 can be reduced. FIG. 3 is a result of electric field analysis using a difference method showing the relationship between the thickness of the extraction electrode (gate electrode) and the current emitted from the tip of the emitter. The horizontal axis is the ratio between the thickness of the extraction electrode (gate electrode) 12 and the height of the emitter 15, and the vertical axis is the current value emitted from the tip of the emitter 15 as 100% when the focusing electrode 13 is not used. It has become. The point A in the figure is the ratio of the emission current using the focusing electrode 13 and the conventional film thickness conditions (emitter height 1 μm, gate electrode thickness 0.3 μm), and the extraction electrode 12 is made thicker. It can be seen that the current emitted from the tip of the emitter 15 increases. For example, when the ratio of the thickness of the extraction electrode (gate electrode) 12 to the height of the emitter 15 is 2 or more, the emission current can be secured at 80% or more. By thickening the extraction electrode (gate electrode) in this way, an electron beam having a high current density and excellent focusing characteristics can be obtained.
[0030]
On the other hand, when the extraction electrode (gate electrode) is thickened, the pitch p between the emitters in FIG. 1 is widened, and the number of emitters per unit area when a plurality of emitters are formed as an electron source is reduced. Therefore, when a plurality of emitters are formed and used as an electron source, the total of the emission currents from all the emitters is determined by the emission current from one emitter and the number of emitters. FIG. 4 shows the total emission current with respect to the ratio of the thickness of the extraction electrode (gate electrode) to the height of the emitter when the total emission current of the emitter group having a focusing action and no reduction in emission current is 100%. It shows the relationship.
[0031]
In FIG. 3, when the ratio of the thickness of the extraction electrode (gate electrode) to the height of the emitter is 2 or more, the emission current per emitter can be secured 80% or more, and the thickness of the extraction electrode (gate electrode) It was found that the height ratio with respect to the emitter is 4 and the total emission current of the emitter group when the focusing electrode is not used can be secured to the same level. Furthermore, as shown in FIG. 4, as the emitter group, if the ratio of the thickness of the extraction electrode (gate electrode) to the height of the emitter is 1 or more, a total emission current equivalent to or higher than the conventional one can be obtained. I understand that
[0032]
On the other hand, as a method of improving the total emission current, there is a method of optimizing the electrode material and applied voltage. For example, in the document “7th International Vacuum Microelectronics Conference 1994 July p. 405-407” in the 7th International Conference on Vacuum Microelectronics, the total emission current can be improved by anodizing the emitter. It has been reported. That is, the decrease in the total emission current can be compensated by optimizing other parameters such as the electrode material and the applied voltage. In FIG. It is possible to cover up to% (2.5 times). That is, if the ratio between the thickness of the extraction electrode (gate electrode) and the height of the emitter is 0.5 or more, it is possible to obtain a total emission current that is the same as or higher than the conventional one.
[0033]
Further, the lead electrode (gate electrode) is preferably thick, but it is difficult to increase the thickness of the electrode in the process, and the total current tends to decrease when the electrode is made thicker in FIG. If the emitter height is 1 μm, the limit of 10 μm, which is 10 times, will be the limit. Further, when the electron source is thinned and the emitter is lowered, the increase gradient in FIG. 3 becomes gentle, and the increase gradient in FIG. 4 also becomes gentle. In that case, it is necessary to further increase the thickness of the electrode with respect to the height of the emitter. In addition, it is not necessary to consider that the height of the emitter is one digit or more larger than 1 μm because it is difficult to reduce the thickness of the electron source and in terms of process.
[0034]
FIG. 5 shows the experimental results of examining changes in the anode current when the thickness of the extraction electrode is increased from the conventional film thickness of 0.3 μm to 3 μm (at this time, the height of the emitter is 1 μm). Even if the voltage applied to the focusing electrode was reduced, the decrease in the anode current was suppressed, and a sufficient current density as an electron source could be secured. Further, in conjunction with FIG. 30 described in the conventional problem, it was possible to provide an electron source with a high current density by focusing an electron beam by reducing an applied voltage.
[0035]
The electrons emitted from the tip of the field emitter 15 are decelerated by the electric field formed by the focusing electrode 13, are focused, and are emitted toward the anode provided outside the electron source.
[0036]
Furthermore, although the electron source having a plurality of emitters has been described in the above embodiment, one emitter may constitute one electron source.
[0037]
Embodiment 2. FIG.
Embodiment 2 of the present invention will be described with reference to the drawings. FIG. 6 is a cross-sectional view showing the main part of the electron source according to the second embodiment. In the figure, the difference from the prior art is that the thickness of the second insulating film 16 between the extraction electrode 12 and the focusing electrode 13 is made sufficiently thick.
[0038]
Next, the operation of the electron source having the above configuration will be described. For example, a voltage of +60 to +110 V is applied to the extraction electrode 12 with respect to the cathode electrode 11. Further, for example, a voltage of 0 to +20 V is applied to the focusing electrode 13 with respect to the cathode electrode 11. At this time, since the focusing electrode 13 that reduces the electric field at the tip of the emitter 15 is separated from the emitter 15, the influence of the electric field from the focusing electrode 13 on the tip of the emitter 15 can be reduced.
[0039]
FIG. 7 is an electric field analysis result using a difference method showing the relationship between the thickness of the second insulating film 16 and the current emitted from the tip of the emitter 15. The horizontal axis represents the ratio between the thickness of the second insulating film 16 and the height of the emitter 15, and the vertical axis represents the current emitted from the tip of the emitter 15 as normalized to 100% when the focusing electrode 13 is not used. It is. Point B in the figure is the ratio of the emission current using the focusing electrode 13 and the conventional film thickness conditions (emitter height 1 μm, second insulating film thickness 1 μm). It can be seen that the emission current from the tip of the emitter 15 increases by increasing the thickness. For example, it can be seen that the ratio of the thickness of the second insulating film 16 to the height of the emitter 15 is 3 or more, and the emission current, which was 10% or less in the past, can be ensured to 30% or more. Accordingly, an electron source capable of generating an electron beam having a high current density even when the electron beam is focused by reducing the potential applied to the focusing electrode as in the first embodiment can be provided.
[0040]
On the other hand, when the thickness of the second insulating film is increased, the pitch p between the emitters in FIG. 6 is increased, and the number of emitters per unit area when a plurality of emitters are formed to form an electron source is reduced. Therefore, when a plurality of emitters are formed and used as an electron source, the total of emission currents from all the emitters is determined by the emission current from one emitter and the number of emitters. FIG. 8 shows the relationship of the total emission current to the ratio between the thickness of the second insulating film and the height of the emitter when the total emission current of the emitter group having a focusing action and no decrease in the emission current is 100%. It is a thing. As shown in FIG. 8, if the ratio of the thickness of the second insulating film to the height of the emitter is at least 2.5 as the emitter group, the total current as the emitter group is saturated at about 40%. As described in the first embodiment, if the total current of the emitter group is about 40%, the total current can be compensated up to 100% by optimizing other parameters. Accordingly, the thickness of the second insulating film may be 2.5 μm if the emitter height is 1 μm. In addition, the upper limit of the thickness will be about 10 μm, which is 10 times, considering the thickening process.
[0041]
Further, when the electron source is thinned and the height of the emitter is reduced, the increase slope in FIG. 7 becomes gentle, and the increase slope becomes gentle in FIG. In that case, the thickness of the electrode needs to be further increased with respect to the height of the emitter, and in that case, there is a possibility that the thickness is 10 times or more. In addition, it is not necessary to consider that the height of the emitter is one digit or more larger than 1 μm because it is difficult to reduce the thickness of the electron source and in terms of process. When the emitter height is larger than 1 μm, the slope becomes steep in both FIGS. 7 and 8, and the ratio of the thickness of the second insulating film to the emitter height may be smaller than 2.5.
[0042]
As in the first embodiment, a single emitter may constitute one electron source.
[0043]
Embodiment 3 FIG.
Embodiment 3 of the present invention will be described with reference to the drawings. FIG. 9 is a cross-sectional view showing the main part of the electron source according to Embodiment 3, and FIG. 10 is a schematic plan view showing the connection state of the electrodes. In the figure, reference numeral 12a denotes a second extraction electrode, which is provided between the first extraction electrode 12 and the focusing electrode 13 via a second insulating film 16 and a third insulating film 36, respectively. Further, as shown in FIG. 10, the second lead electrode 12a has a linear wiring 21a connected to a bonding terminal (electrode terminal) 19a constituting a terminal portion for supplying power to the second lead electrode 12a from one place. It extends and is exposed in the upper space. Further, a conductive wire 24a for supplying a voltage is connected to the bonding terminal 19a.
[0044]
Next, the operation of the electron source having the above configuration will be described. For example, a voltage of +60 to +110 V is applied to the first extraction electrode 12 with respect to the cathode electrode 11. Further, for example, a voltage of 0 to +20 V is applied to the focusing electrode 13 with respect to the cathode electrode 11. A potential higher than that of the focusing electrode 13 and lower than that of the first extraction electrode 12, for example, +50 V, is applied to the second extraction electrode 12a. Then, the electric field strength in the vicinity of the tip of the emitter 15 plays a role of shielding the influence of the electric field strength of the focusing electrode 13 by the second extraction electrode 12a, and sufficient electric field strength is obtained. Therefore, an electron source that can generate an electron beam with a high current density even when the electron beam is focused by reducing the potential applied to the focusing electrode as in the first and second embodiments can be provided. As described above, since it is not necessary to make the thickness of each layer extremely thick as compared with the conventional ones as in the first and second embodiments by forming a multilayer, problems caused by increasing the thickness of each film, for example, It is possible to ignore internal stresses in the film.
[0045]
Embodiment 4 FIG.
Embodiment 4 of the present invention will be described with reference to the drawings. FIG. 11 is a cross-sectional view showing the main part of the electron source according to Embodiment 4, and FIG. 12 is a schematic plan view showing the connection state of the electrodes. In the third embodiment, the potential applied to the second extraction electrode 12a is an intermediate potential between the potentials applied to the first extraction electrode 12 and the focusing electrode 13, but in the fourth embodiment, an external circuit is used. The first extraction electrode 12 and the second extraction electrode 12a are electrically connected to have the same potential. In FIG. 11, the external circuit constituting the conducting portion is formed on the same substrate as each electrode, 38 is an electrode terminal provided in the bonding terminal portion, and the first lead electrode 12 and the second lead electrode 12a is electrically short-circuited outside the opening 10.
[0046]
For the electron source configured as described above, a voltage of, for example, +60 to +110 V is applied to the cathode electrode 11 to the first extraction electrode 12 and the second extraction electrode 12 a, and the cathode electrode 11 is applied to the focusing electrode 13. For example, a voltage of 0 to + 20V is applied.
[0047]
With such a configuration, the thickness of each layer can be reduced as in the third embodiment, so that problems caused by increasing the thickness of each film, such as internal stress and peeling in the film, can be ignored. it can. In addition, as shown in FIG. 12, since the electrode terminals 38 of the first extraction electrode 12 and the second extraction electrode 12a are common, the number of electrode terminals can be reduced, and the influence of an asymmetric electric field from the electrode terminals or the like can be reduced. Can be small. Furthermore, the number of power sources can be reduced, and a high-performance electron source can be obtained with a simple configuration.
[0048]
In FIG. 11, the first extraction electrode and the second extraction electrode are short-circuited in an external circuit provided on the same substrate as each electrode, but an external circuit between the power source and the electrode terminal (outside the substrate). May be short-circuited. In this way, the number of electrode terminals is not reduced, but manufacturing is facilitated.
Further, the first extraction electrode and the second extraction electrode may be directly short-circuited inside the electrodes without passing through the wirings 21 and 21a. In this way, the wirings 21 and 21a become one, and the configuration is simpler.
[0049]
FIG. 13 shows the relationship between the ratio of the film thickness of the extraction electrode to the height of the emitter and the electric field strength at the tip of the emitter, and the first and second are divided into two in the first embodiment. The second lead electrode is provided in the middle of the second insulating film having the conventional thickness (the insulating film is separated into the second insulating film 16 and the third insulating film 36 in FIG. 11), and the first leading electrode is provided. And the effect of the three-stage electrode (two-stage extraction electrode and one-stage focusing electrode) employing the second extraction electrode of the present embodiment when the same potential is applied to the second extraction electrode. is there. It was confirmed that when the ratio of the thickness of the extraction electrode to the height of the emitter was 2, the same effect as in the first embodiment was obtained. Here, in the three-stage electrode, the thickness of the extraction electrode is the sum of the thicknesses of the first and second extraction electrodes and the second insulating film, so the thickness of each layer is smaller than that of the first embodiment. can do. Further, if the potential applied to the first and second extraction electrodes is adjusted, it is not necessary to increase the thickness of the first and second extraction electrodes.
[0050]
Embodiment 5 FIG.
Embodiment 5 of the present invention will be described with reference to the drawings. FIG. 14 is a sectional view showing the main part of the electron source according to the fifth embodiment. In the figure, a second extraction electrode 12 a is provided between the first extraction electrode 12 and the focusing electrode 13 via insulating films 16 and 36, respectively, and the first extraction electrode 12 and the second extraction electrode 12 a are formed on the inner wall of the opening 10. An electrode surface 37 for connecting the extraction electrode 12a was provided.
[0051]
With such a configuration, it is not necessary to connect the first extraction electrode 12 and the second extraction electrode 12a with an external circuit, and the structure is simplified. In addition, the influence of the potential applied to the extraction electrode can be easily applied to the electric field formed inside the opening, the electric field at the tip of the cathode electrode can be prevented from being lowered, and an electron beam with high current density and excellent focusing characteristics can be obtained.
[0052]
Embodiment 6 FIG.
Embodiment 6 of the present invention will be described with reference to the drawings. The structure of the electron source according to the sixth embodiment is the same as that of the third embodiment shown in FIGS. 9 and 10, but the voltage applied to each electrode is different.
[0053]
The operation of this electron source will be described. In FIG. 9, for example, a voltage of +60 to +110 V is applied to the first extraction electrode 12 with respect to the cathode electrode 11. A voltage higher than that of the first extraction electrode 12, for example, +80 to +160 V is applied to the cathode electrode 11 to the second extraction electrode 12 a. Further, for example, +20 to +80 V is applied to the focusing electrode 13 with respect to the cathode electrode 11. At this time, the influence of the electric field from the focusing electrode 13 that lowers the electric field at the tip of the emitter 15 can be shielded by the voltage applied to the second extraction electrode 12 a, and the focusing electrode 13 itself is also separated from the emitter 15. The influence of the electric field from the focusing electrode 13 on the 15 tip can also be reduced. Since an electric field necessary for electron emission is generated in the emitter 15 by the voltage applied to the first extraction electrode 12, electrons are emitted. By using this method, the electrons emitted from the tip of the emitter 15 are decelerated by the electric field formed by the focusing electrode 13, are focused, and are emitted toward the anode provided outside the electron source.
[0054]
Thus, by making the voltage applied to the second extraction electrode 12 a higher than the voltage applied to the first extraction electrode 12, the second insulating film 16 is made thinner than those of the above-described third to fifth embodiments, so that the entire Even if the film thickness is reduced and the distance between the first extraction electrode and the second extraction electrode is reduced, the electron beam is the same as the first extraction electrode and the second extraction electrode having the same potential. Can be obtained. Further, since the voltage applied to the focusing electrode becomes higher with respect to the cathode electrode, the influence of the decrease in the electric field at the tip of the cathode electrode is reduced.
[0055]
Embodiment 7 FIG.
Embodiment 7 of the present invention will be described with reference to the drawings. FIG. 15 is a cross-sectional view showing the main part of the electron source according to Embodiment 7, and FIG. 16 is a schematic plan view showing the connection state of the electrodes. In the figure, the three-stage electrode type of the third to sixth embodiments is different from the third-stage electrode type in that the second extraction electrode 12a and the focusing electrode 13 are formed in the same plane, and the third insulating film is eliminated to form a two-layer electrode type. There is.
[0056]
Next, the operation of the electron source having the above configuration will be described. For example, a voltage of +60 to +110 V is applied to the first extraction electrode 12 with respect to the cathode electrode 11. Further, for example, a voltage of 0 to +20 V is applied to the focusing electrode 13 with respect to the cathode electrode 11. A potential higher than that of the focusing electrode 13 and lower than that of the first extraction electrode 12, for example, +50 V, is applied to the second extraction electrode 12a. Then, the electric field intensity near the tip of the emitter 15 serves to shield the influence of the electric field intensity of the focusing electrode 13 by the second extraction electrode 12a, and a sufficient electric field intensity is obtained. Therefore, as in Embodiment 3, it is possible to provide an electron source that can generate an electron beam having a high current density even when the electron beam is focused by reducing the potential applied to the focusing electrode.
[0057]
With such a configuration, the total film thickness can be reduced compared to the above embodiments, and the thickness of each layer can be reduced. Problems caused by increasing the thickness, for example, internal stress and peeling in the film can be ignored, and the manufacture is facilitated. In addition, since the shapes of the second extraction electrode 12a and the focusing electrode 13 are created simultaneously, the number of manufacturing steps can be reduced as compared with the conventional three-stage electrode type. With the above two points, it is possible to realize a reduction in manufacturing cost, an improvement in yield, and the like.
[0058]
In the present embodiment, the voltage applied to the second extraction electrode 12a is lower than the voltage applied to the first extraction electrode 12. However, as in the fourth embodiment, the first extraction electrode 12 and the first extraction electrode 12 are connected to each other by an external circuit. For example, the first lead electrode 12 and the second lead electrode 12a have a voltage of +60 to + 110V with respect to the cathode electrode 11, and the focusing electrode 13 has a voltage of 0 to + 20V with respect to the cathode electrode 11. By applying this voltage, a high-performance electron source can be obtained with a simple configuration.
[0059]
Further, in FIG. 15, as in the sixth embodiment, for example, the first lead electrode 12 has a voltage of +60 to +110 V with respect to the cathode electrode 11, and the second lead electrode 12a has a voltage of +80 with respect to the cathode electrode 11. By applying +20 to +80 V to the focusing electrode 13 and +20 to +80 V to the cathode electrode 11 to increase the voltage applied to the second extraction electrode 12 a higher than the voltage applied to the first extraction electrode 12, the second insulation is achieved. The film 16 can be made thinner, and the overall film thickness can be made thinner.
[0060]
Embodiment 8 FIG.
An embodiment of the present invention will be described with reference to the drawings. FIG. 17 is a cross-sectional view showing the main part of the electron source according to Embodiment 8, and FIG. 18 is a schematic plan view showing the connection state of the electrodes. In the figure, the difference from the seventh embodiment is the method of the linear wiring 21a that connects the second extraction electrode 12a and the bonding terminal 19a. That is, the wiring 21a is not formed on the same plane as the second extraction electrode 12a and the focusing electrode 13 by the wiring pattern as shown in FIG. 16, but the second extraction electrode 12a and the focusing electrode as shown in FIG. This is because the wiring 21 a is formed on the plane different from 13 through the insulating layer 35.
[0061]
By doing so, since the focusing electrode 13 is not divided by the wiring 21a, the symmetry of the electric field by the focusing electrode 13 is maintained, and an electron source that emits an electron beam with excellent focusing characteristics can be obtained.
[0062]
Embodiment 9 FIG.
Embodiment 9 of the present invention will be described with reference to the drawings. FIG. 19 is a cross-sectional view showing the main part of the electron source according to the ninth embodiment, and FIG. 20 is a schematic plan view showing the connection state of the electrodes. This embodiment is a two-layer electrode type as in the seventh embodiment, but is different from the seventh embodiment shown in FIG. 15 in that the first extraction electrode 12 and the second extraction electrode 12a are formed in the opening 10. Is electrically connected by the electrode surface 37 to the same potential.
[0063]
With such a configuration, the decrease in the electric field at the tip of the electron emission portion due to the potential applied to the focusing electrode 13 can be easily shielded by the potentials of the first extraction electrode 12 and the second extraction electrode 12a. Furthermore, it is not necessary to connect the first extraction electrode 12 and the second extraction electrode 12a with an external circuit, the structure is simplified, the symmetry of the electric field by the focusing electrode 13 is maintained, and the electron having excellent focusing characteristics. An electron source emitting a line is obtained.
[0064]
Embodiment 10 FIG.
Embodiment 10 of the present invention will be described with reference to the drawings. FIG. 21 shows a process for manufacturing an electron source by increasing the thickness of each layer as compared with the first and second embodiments. The figure shows the state of the manufacturing process when the thickness of the circular mask 29 for forming the opening 10 is set to a predetermined thickness when the extraction electrode 12 and the insulating films 16 and 17 are formed by vapor deposition. Yes.
[0065]
In FIG. 2A, a circular mask material (for example, SiO 2) 30 which is thicker than a conventional material and designed to have a predetermined thickness is formed on an emitter material (for example, Si) 28 on a substrate 14 made of, for example, a glass material. Next, in (b), the circular mask material 30 is processed into a circular shape for forming the emitter 15 to produce a circular mask 29. In (c), the emitter material 28 is processed into the emitter 15 having a desired shape by using the circular mask 29. In (d), a first insulating film (for example, SiO 2) 17 and a lead electrode (for example, a metal such as Nb, Au, Pt, etc., or an external material for Au are simultaneously formed on the circular mask 29 and the portion of the substrate 14 where the emitter 15 is not formed. 12 is good for connection with the terminal), the second insulating film (for example, SiO2) 16, the focusing electrode (for example, metal such as Nb, Au, Pt, etc., and the connection with the external terminal is good for Au) 13. In order, they are formed by vapor deposition. At this time, the insulating material and the electrode material do not adhere to the emitter 15 due to the protection of the circular mask 29. In (e), the circular mask 29 and the unnecessary vapor deposition material 31 on the circular mask are removed by etching (for example, using a hydrofluoric acid solution).
[0066]
Next, a method for designing the thickness of the circular mask will be described. FIG. 22 shows the difference in the formation of the electron source due to the difference in the thickness of the circular mask. In the drawing, (a) shows the state when the film is formed without optimizing the thickness of the circular mask, and (b) shows the state when the film is formed with the circular mask having an appropriate thickness. . In the figure, de is the height of the emitter, dm is the thickness of the mask, d is the thickness from the substrate 14 of the film (regardless of type) during film formation in the case of forming the film in FIG. ro and ri indicate the diameter of the opening 10 and the diameter of the deposit on the mask 29 at the height of d, respectively, and r indicates the opening diameter on the substrate. During the film formation, the film on the substrate 14 is formed so that the opening is widened, and the film on the circular mask 29 is formed so as to spread from the diameter of the mask. At this time, since the spread of the film on the circular mask 29 from the diameter of the mask is larger than the spread of the film on the substrate 14, the circular mask must be sufficiently thick as shown in FIG. Before the film was completed, the opening was blocked, and in step (e) in FIG. 21, it was difficult to remove the unnecessary vapor deposition material, and an electron source could not be produced. Therefore, the circular mask may be sufficiently thick as shown in FIG.
[0067]
Next, a specific method for setting the thickness of the circular mask will be described. FIG. 23 is a graph showing the relationship between the diameter ro of the opening 10 and the diameter ri of the deposited material on the mask 29 at the height d from the substrate. When the height of the conventional emitter is 1 μm, the mask dm1 is 0.3 μm, and the opening diameter on the substrate is 1.8 μm, the intersection of ro and ri is about 3.2 μm. The first insulating film 17 is about 1 μm, the extraction electrode 12 is 0.3 μm, the second insulating film 16 is about 1 μm, the focusing electrode 13 is 0.3 μm, and the total film thickness is 2.6 μm. It is possible to produce a sufficient electron source without any problems. On the other hand, when the insulating film is designed as in the second embodiment, for example, if the second insulating film 16 is 3 μm, the total film thickness is 4.6 μm. The electron source cannot be manufactured without increasing the thickness of the circular mask. Therefore, from FIG. 23, ri is translated in the d direction so that d is 4.6 μm or more and ro and ri have intersections. The dm2 at that time is the design mask thickness. In this embodiment, it can be seen that if the thickness of the mask is 1 μm or more, the electron source can be manufactured without blocking the opening.
[0068]
Further, when the extraction electrode is 3 μm in the first embodiment, the total film thickness is 5.3 μm. At this time, when the graph is extrapolated, it is understood that the thickness of the circular mask needs to be 1.4 μm or more.
[0069]
Although the slope of this graph varies slightly depending on the type of vapor deposition apparatus, etc., if the relationship between ro and ri is obtained in advance, the optimum circular mask thickness can be designed using the same method even if different apparatuses are used. be able to.
[0070]
In the first to tenth embodiments, the emitter 15 is formed on the substrate 14. However, a structure in which a single Si substrate is used and the emitter and the substrate are integrated by processing this may be used. .
[0071]
Embodiment 11 FIG.
Embodiment 11 of the present invention will be described with reference to the drawings. FIG. 24 is a sectional view showing an electron source manufactured by the manufacturing method according to the tenth and eleventh embodiments, for example. In the electron source (FIG. 24 (a)) formed as in the tenth embodiment, the film thickness of the extraction electrode 12 is larger than that of the conventional extraction electrode. Due to the influence of the above, etc., it is likely to be stepped, or the corner of this step is likely to have a sharp shape, abnormal discharge occurs between the emitter 15 and the extraction electrode 12, or initial failure occurs due to a short circuit between the electrodes. There was a thing. In the present embodiment, in order to prevent this, a wet etching process is further performed in addition to the manufacturing method of the tenth embodiment.
[0072]
For example, the lead electrode 12, the focusing electrode 13, the substrate 14, the emitter 15, the first insulating film 17, and the second insulating film 16 are respectively Au, Nb, Si, Si, and SiO.₂, SiO₂Create with. After formation, for example, only Au of the extraction electrode 12 is slightly wet-etched with aqua regia or the like so that the corner portion 40 of the extraction electrode 12 in the opening becomes a flat surface 41 with respect to the emitter 15, and the sharp portion is eliminated, The shape of the extraction electrode is rounded to a shape as shown in FIG.
[0073]
In this way, when a voltage is applied to the extraction electrode 12 in order to emit electrons from the emitter 15 by eliminating the sharpness and making the shape round, an abnormal discharge occurs between the emitter 15 and the extraction electrode 12. It becomes difficult.
In addition, there is a foreign substance of Au due to wraparound during film formation between the extraction electrode and the cathode electrode, and an initial failure may occur due to a short circuit between the electrodes, but with a sharp portion due to wet etching By removing foreign matters, initial defects can be reduced and yield is improved.
[0074]
Embodiment 12 FIG.
Embodiment 12 of the present invention will be described with reference to the drawings. FIG. 25 is a cross-sectional configuration diagram of a cathode ray tube using the electron source according to any one of the first to eleventh embodiments. In the figure, an electron beam 53 emitted from an electron source 51 composed of one or a plurality of emitters forms a crossover point 59 in an electron gun 52 which is an electron beam focusing means and is deflected by a deflecting magnet 54. Then, it is led to a desired position of the phosphor 56 having the aluminum film 57 through the shadow mask 55. What constitutes the cathode ray tube is accommodated in a vacuum vessel 58.
[0075]
As described above, when the electron source according to any of Embodiments 1 to 11 is used for the cathode ray tube, the electron beam emitted from the electron source is already focused, and thus a sufficiently focused electron beam is obtained. The resolution as a tube is improved.
[0076]
Embodiment 13 FIG.
Another embodiment of the present invention will be described with reference to the drawings. FIG. 26 is a cross-sectional configuration diagram of a cathode ray tube using the electron source according to any one of the first to eleventh embodiments. In the figure, the electron source 51 is divided into three electron sources 51R, 51G, and 51B, and the electron beams emitted from the respective electron sources are crossover points 59 (each of which is in an electron gun 52, which is an electron beam focusing unit). 59R, 59G, 59B) and deflected by the deflecting magnet 54 and having the aluminum film 57 through the shadow mask 55, the red phosphor portion, the green phosphor portion, and the blue phosphor portion, respectively. Led to. This apparatus is also housed in a vacuum vessel.
[0077]
As described above, when the electron source according to any one of Embodiments 1 to 11 is used for the cathode ray tube, the electron beam emitted from the electron source is already focused, so that a sufficiently focused electron beam is obtained. The resolution as a tube is improved, the quality as a color image is improved in this embodiment, and a cathode ray tube with high performance can be provided.
[0078]
The crossover points in the electron guns of the twelfth and thirteenth embodiments may not be formed as long as sufficient focusing is possible.
[0081]
【The invention's effect】
As described above, according to the present invention,Since the ratio of the thickness of the extraction electrode to the height of the substantially cone-shaped electron emission portion of the cathode electrode is 0.5 or more, the extraction electrode is thicker than before, and the distance between the focusing electrode and the electron emission portion can be secured, and Since the thickness of the extraction electrode is sufficiently thick, it is possible to prevent a decrease in the electric field at the tip of the electron emission portion, that is, the cathode electrode, it is easy to give the potential of the extraction electrode to the electron emission portion, and An emitting electron source can be provided.
[0082]
Further, in the electron source, since the ratio of the thickness of the extraction electrode to the height of the substantially cone-shaped electron emission portion of the cathode electrode is set to 1 or more, the extraction electrode is thicker than before, and the distance between the focusing electrode and the electron emission portion Can be ensured, and the thickness of the extraction electrode is sufficiently thick, so that the electric field at the tip of the electron emission portion, that is, the cathode electrode can be prevented from being lowered, and the potential of the extraction electrode can be easily applied to the electron emission portion. An electron source that emits an excellent electron beam can be provided. Furthermore, when the emitter group is formed, the total amount of current can be secured at the same level as the emitter group that has a focusing action and does not decrease the emission current without operating other parameters, and provides a high-performance electron source. Can do.
[0084]
Also, MosquitoSince the ratio of the thickness of the second insulating layer to the height of the substantially conical electron emission portion of the sword electrode is set to 2.5 or more, the extraction electrode is thicker than before and the distance between the focusing electrode and the electron emission portion is secured. An electron source that emits an electron beam that can prevent a drop in the electric field at the electron emission portion, that is, the cathode electrode tip, can easily control electron emission at a predetermined extraction potential, and has a high current density and excellent focusing characteristics. can do.
[0085]
Also, CollectionA second extraction electrode is provided between the bundle electrode and the extraction electrode (first extraction electrode).The extraction electrode (first extraction electrode) and the second extraction electrode are set to the same potential, and the extraction electrode (first extraction electrode) and the second extraction electrode are connected to each other at the inner surface of the opening.BecauseAs in the case of using a thick extraction electrode, the distance between the focusing electrode and the electron emission portion can be secured, and the effective thickness of the effective extraction electrode formed by the first extraction electrode and the second extraction electrode is sufficient. It is thick, and it is easy to give the influence of the potential applied to the extraction electrode to the electric field formed inside the opening,It is possible to provide an electron source that can prevent a decrease in the electric field at the electron emission portion, that is, the cathode electrode tip, emits an electron beam having a high current density and excellent focusing characteristics.Further, since it is not necessary to increase the thickness of one electrode, the manufacturing process is facilitated and the yield is improved.
[0086]
Also, CollectionSince the second extraction electrode is provided on the same plane as the bundle electrode and on the opening side of the focusing electrode, it is possible to prevent a decrease in the electric field at the electron emission portion, that is, the cathode electrode tip, and the current density is high and the focusing property is excellent. An electron source that emits an electron beam can be provided. Furthermore, the total film thickness can be reduced, manufacturing becomes easy, and manufacturing costs can be reduced and yield can be improved.
[0087]
In the electron source, since the extraction electrode (first extraction electrode) and the second extraction electrode have the same potential, the distance between the focusing electrode and the electron emission portion is the same as in the case where the thick extraction electrode is used. Since the effective extraction electrode formed by the first extraction electrode and the second extraction electrode is sufficiently thick, it is possible to prevent a reduction in the electric field at the electron emission portion, that is, the cathode electrode tip. Can be easily applied to the electron-emitting portion, and an electron source that emits an electron beam having a high current density and excellent focusing characteristics can be provided. Further, since it is not necessary to increase the thickness of one electrode, the manufacturing process is facilitated and the yield is improved.
[0088]
In the electron source, since the extraction electrode (first extraction electrode) and the second extraction electrode are connected to each other on the inner surface of the opening, an electric field formed inside the opening is affected by the potential applied to the extraction electrode. Therefore, it is possible to provide an electron source that emits an electron beam having a high current density and excellent focusing characteristics.
[0089]
In the electron source, since the extraction electrode (first extraction electrode) and the second extraction electrode are connected outside the opening, an electron source that emits an electron beam with high current density and excellent focusing characteristics can be easily obtained. Can be manufactured.
[0090]
In the electron source, since the potential applied to the second extraction electrode is set higher than the potential applied to the extraction electrode (first extraction electrode), the entire film thickness is reduced, and the first extraction electrode and the first extraction electrode Even if the distance between the two extraction electrodes is reduced, the effect of focusing the electron beam can be obtained in the same manner as when the first extraction electrode and the second extraction electrode have the same potential. Can be provided. Further, since the film thickness can be reduced, the manufacturing process is facilitated and the yield is improved.
[0091]
In addition, since any one of the electron sources is mounted in the cathode ray tube, the electron beam having high focusing property and a high current density can be emitted from the electron source. A high performance cathode ray tube can be provided.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a configuration of a main part of an electron source according to a first embodiment.
2 is a schematic plan view showing a connection state of electrodes of an electron source according to Embodiment 1. FIG.
FIG. 3 is a graph of an electric field analysis result showing a relationship between the thickness of the extraction electrode and the emission current.
FIG. 4 is a graph of electric field analysis results showing the relationship between the thickness of the extraction electrode and the total emission current.
FIG. 5 is a graph showing the relationship between the voltage applied to the focusing electrode and the anode current when the thickness of the extraction electrode is changed.
FIG. 6 is a cross-sectional view showing a configuration of a main part of an electron source according to a second embodiment.
FIG. 7 is a graph of electric field analysis results showing the relationship between the thickness of the second insulating film and the emission current.
FIG. 8 is a graph of electric field analysis results showing the relationship between the thickness of the second insulating film and the total emission current.
9 is a cross-sectional view showing a configuration of a main part of an electron source according to Embodiment 3. FIG.
10 is a schematic plan view showing a connection state of electrodes of an electron source according to Embodiment 3. FIG.
FIG. 11 is a cross-sectional view showing a configuration of a main part of an electron source according to a fourth embodiment.
12 is a schematic plan view showing a connection state of electrodes of an electron source according to Embodiment 4. FIG.
FIG. 13 is a graph showing the effect of a three-stage electrode structure (with a second extraction electrode).
FIG. 14 is a cross-sectional view showing a configuration of a main part of an electron source according to a fifth embodiment.
FIG. 15 is a cross-sectional view showing a configuration of a main part of an electron source according to a seventh embodiment.
FIG. 16 is a schematic plan view showing a connection state of electrodes of an electron source according to a seventh embodiment.
FIG. 17 is a cross-sectional view showing a configuration of a main part of an electron source according to an eighth embodiment.
FIG. 18 is a schematic plan view showing a connection state of electrodes of an electron source according to an eighth embodiment.
FIG. 19 is a cross-sectional view showing a configuration of a main part of an electron source according to a ninth embodiment.
20 is a schematic plan view showing a connection state of electrodes of an electron source according to Embodiment 9. FIG.
FIG. 21 is a cross-sectional view showing an electron source manufacturing process according to the tenth embodiment;
FIG. 22 is a schematic diagram showing the quality of manufacturing an electron source due to a difference in mask thickness.
FIG. 23 is a graph showing the relationship between the diameter of the deposit on the mask and the inner diameter of the deposit on the substrate for determining the mask thickness.
24 is a cross-sectional view showing an electron source manufactured by an electron source manufacturing method according to Embodiment 10 and Embodiment 11. FIG.
25 is a cross-sectional configuration diagram of a cathode ray tube equipped with an electron source according to any of Embodiments 1 to 11. FIG.
FIG. 26 is a cross-sectional configuration diagram of a cathode ray tube in which a plurality of electron sources according to any of Embodiments 1 to 11 are mounted.
FIG. 27 is a sectional view showing a conventional electron source.
FIG. 28 is a cross-sectional view showing a manufacturing process of a conventional electron source.
FIG. 29 is a sectional view showing a conventional cathode ray tube.
FIG. 30 is a graph showing a relationship between a voltage applied to a focusing electrode of a conventional electron source, an anode current, and an electron beam divergence angle.
[Explanation of symbols]
10 opening, 11 cathode electrode,
12 extraction electrode (first extraction electrode), 12a second extraction electrode,
13 focusing electrode, 14 substrate, 15 emitter,
16 second insulating film, 17 first insulating film, 18 electrode terminal,
19 electrode terminal, 19a electrode terminal, 20 wiring, 21 wiring,
21a wiring, 22 wiring, 23 electrode terminal, 24 lead wire,
24a conductor, 25 conductor, 26 conductor, 28 emitter material,
29 circular mask, 30 circular mask material, 31 unnecessary deposit,
35 insulating layer, 36 third insulating film, 37 electrode surface of the inner wall of the opening,
38 electrode terminals, 51, 51R, 51G, 51B electron source,
52 electron gun, 53 electron beam, 54 deflection magnet, 55 shadow mask,
56 phosphor, 57 aluminum film, 58 vacuum vessel,
59, 59R, 59G, 59B Crossover point,
100 electron beam, 101 cathode electrode (substrate), 101a oxide film,
102 extraction electrode, 103 focusing electrode, 104 emitter,
105 insulating film, 106 insulating film, 107 third insulating film,
108 accelerating electrode, 109 power supply for extraction electrode,
110 power supply for focusing electrode, 111 power supply for acceleration electrode,
112 mask, 113a, 113b photoresist,
A cathode comprising a 121 field emitter;
122 anode electrode, 123 anode electrode, 124 electron lens,
125 electron lens, 126 convergence electrode,
127 crossover point, 128 deflection magnet,
129 shadow mask, 130 aluminum film,
131 Phosphor with aluminum back.

Claims

A first insulating layer, an extraction electrode for extracting electrons from the cathode electrode portion, and a second insulation are sequentially formed on the cathode electrode having the substantially conical electron emission portion so as to surround the electron emission portion by forming an opening. In an electron source comprising a layer, a focusing electrode for focusing the extracted electrons, and means for shielding the influence of the electric field formed by the potential applied to the focusing electrode on the electron emission portion of the cathode electrode The means for shielding the influence of the electric field formed by the potential applied to the focusing electrode on the electron emission portion of the cathode electrode is the ratio of the thickness of the extraction electrode to the height of the substantially cone-shaped electron emission portion of the cathode electrode. There child source electrostatic you being a lead-out electrode of 0.5 or more in thickness.

The means for shielding the influence of the electric field formed by the potential applied to the focusing electrode on the electron emission portion of the cathode electrode is that the ratio of the thickness of the extraction electrode to the height of the substantially cone-shaped electron emission portion of the cathode electrode is The electron source according to claim 1 , wherein the electron source is an extraction electrode having a thickness of one or more.

On the cathode electrode having a substantially conical electron emission portion, an opening is formed to surround the electron emission portion, in order, a first insulating layer, an extraction electrode for extracting electrons from the cathode electrode portion, and a second insulation In an electron source comprising a layer, a focusing electrode for focusing the extracted electrons, and means for shielding the influence of the electric field formed by the potential applied to the focusing electrode on the electron emission portion of the cathode electrode The means for shielding the influence of the electric field formed by the potential applied to the focusing electrode on the electron emission portion of the cathode electrode is the thickness of the second insulating layer with respect to the height of the substantially cone-shaped electron emission portion of the cathode electrode. child source electrostatic you being a second insulating layer of the ratio is 2.5 or more in thickness.

On the cathode electrode having an electron emission portion of the substantially conical first insulating layer in order to surround the electron emission portion to form an opening, the extraction electrode for drawing electrons from the cathode electrode portion (the first extraction Electrode), a second insulating layer, and a focusing electrode for focusing the extracted electrons, and the influence of the electric field formed by the potential applied to the focusing electrode on the electron emission portion of the cathode electrode is shielded. In the electron source provided with the means, means for shielding the influence of the electric field formed by the potential applied to the focusing electrode on the electron emission portion of the cathode electrode is provided between the focusing electrode and the extraction electrode (first extraction electrode). Are provided with a second lead electrode , the lead electrode (first lead electrode) and the second lead electrode have the same potential, and the lead electrode (first lead electrode) and the second lead electrode are opened. Child source electrostatic characterized in that characterized in that connected at the inner surface of the part.

On the cathode electrode having an electron emission portion of the substantially conical first insulating layer in order to surround the electron emission portion to form an opening, the extraction electrode for drawing electrons from the cathode electrode portion (the first extraction Electrode), a second insulating layer, and a focusing electrode for focusing the extracted electrons, and the influence of the electric field formed by the potential applied to the focusing electrode on the electron emission portion of the cathode electrode is shielded. In the electron source comprising the means, means for shielding the influence of the electric field formed by the electric potential applied to the focusing electrode on the electron emission portion of the cathode electrode is on the same plane as the focusing electrode and the opening of the focusing electrode child source electrostatic you, characterized in that the part side provided with the second lead electrode.

6. The electron source according to claim 5 , wherein the extraction electrode (first extraction electrode) and the second extraction electrode have the same potential.

The electron source according to claim 6 , wherein the extraction electrode (first extraction electrode) and the second extraction electrode are connected by an inner surface of the opening.

The electron source according to claim 6 , wherein the extraction electrode (first extraction electrode) and the second extraction electrode are connected outside the opening.

6. The electron source according to claim 5 , wherein the potential applied to the second extraction electrode is higher than the potential applied to the extraction electrode (first extraction electrode).

The electron source according to any one of claims 1 to 9 , a means for focusing the electron beam emitted from the electron source, and the focused electron beam at a predetermined position of the phosphor in a vacuum vessel. And a means for deflecting and guiding the cathode ray tube.