JP2004134229A - Electron emitting element, fluorescent light emitting device using the same, image plotting device using the element, cooling element, and power generating element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high efficiency electron emitting element, an image plotting device using it, a cooling element and a power generating element. <P>SOLUTION: The electron emitting element has a substrate, an electrically conductive layer or a semiconductive layer which supplies electrons, an electron emitting layer that emits the electrons, and a control electrode layer disposed via a space with the electron emitting layer that controls the amount of electron emission by applying voltage, wherein an electron emitting element surface having a stable low work function is realized and the high efficiency electron emission is realized, using an oxide crystal material containing alkaline metal or alkaline earth metal for the electron emitting layer. <P>COPYRIGHT: (C)2004,JPO

Description

【００４５】
（第２の実施形態）
第１の実施形態と同様の構造からなる電子放射素子を作製する際、電子放射層に用いる材料を別な形態で作製し、図１の電子放射素子の作製を行った。
【００４６】
まず、基本となる電子放射素子についてＮｂを０．０１ｗｔ％ドープしたＳｒＴｉＯ_３からなる基材の一表面上に電子供給層として金属性下部電極を形成した。前記の様に下部電極材料として特に限定はされないが、本実施形態では厚さ５００ｎｍにてＳｒＲｕＯ_３の膜を用いた。なお、製膜は５５０℃加熱にてスパッタ法により行った。
【００４７】
その上に、（Ｌａ，Ｓｒ）ＴｉＯ_３をターゲットとして、レーザーアブレーション法により電子放射層の形成を行った。レーザー光源はＫｒＦエキシマレーザーを用いて、製膜においては、アブレーションエネルギー密度０．１−１０Ｊ／ｃｍ^２、４００−７００℃加熱中、０．１−５００ｍＴｏｒｒ酸素雰囲気中にて行った。作製した電子放射層の厚みはおよそ３００ｎｍとした。なおここではレーザーアブレーション法により作製を行ったが、イオンビ−ムデポジション（ＩＢＤ）、クラスタ−イオンビ−ムまたはＲＦ、ＤＣ、ＥＣＲ、ヘリコン、ＩＣＰまたは対向タ−ゲットなどのスパッタリング法、ＭＢＥ、イオンプレ−ティング法等のＰＶＤ法や、その他ＣＶＤ、メッキ法あるいはゾルゲル法で作製することができ、限定されない。
【００４８】
その後、実施例１と同様に、二酸化ケイ素からなる絶縁体層及び制御電極となる上部電極を形成し、一般的なリソグラフィー工程を用いて図１に記載した様な構造の電子放射素子を作製した。
【００４９】
以上の様にして作製した電子放射素子を真空槽内に配置し、下部電極（電子供給層）と制御電極との間に制御電極側を正とした電圧を印加し、放射電流量を測定した。その結果、第１の実施形態とほぼ同じ放射電流密度が得られた。
【００５０】
その他の材料を電子放射層に用いた場合について表２に示す。いずれの場合にも、実施例１同様、従来に比べ高い放射電流密度が得られた。
【００５１】
【表２】

【００５２】
さらに、電子放射層に用いた場合について表３に示した場合にも、従来に比べ高い放射電流密度が得られた。
【００５３】
【表３】

【００５４】
（第３の実施形態）
第１の実施形態と同様の構造からなる電子放射素子を作製する際、電子放射層に用いる材料を別な形態で作製し、図１の電子放射素子の作製を行った。
【００５５】
まず、基本となる電子放射素子についてＮｂを０．０１ｗｔ％ドープしたＳｒＴｉＯ_３からなる基材の一表面上に電子供給層として金属性下部電極を形成した。前記の様に下部電極材料として特に限定はされないが、本実施形態では厚さ５００ｎｍにてＳｒＲｕＯ_３の膜を用いた。なお、製膜は５５０℃加熱にてスパッタ法により行った。
【００５６】
その上に、（Ｌａ，Ｓｒ）_２ＴｉＯ_４をターゲットとして、レーザーアブレーション法により電子放射層の形成を行った。レーザー光源はＫｒＦエキシマレーザーを用いて、製膜においては、アブレーションエネルギー密度０．１−１０Ｊ／ｃｍ^２、４００−７００℃加熱中、０．１−５００ｍＴｏｒｒ酸素雰囲気中にて行った。作製した電子放射層の厚みはおよそ３００ｎｍとした。作製した（Ｌａ，Ｓｒ）_２ＴｉＯ_４は電子放射面としてａｂ面が支配的となるように配している。（Ｌａ，Ｓｒ）_２ＴｉＯ_４はＫ_２ＮｉＦ_４構造を有した物質で、図６（ａ）に示す結晶構造を有している。図５のＡＢＺ_３の構造同様に、アルカリ土類金属元素である（Ｓｒ，Ｂａ，Ｃａ）を表面に効率よく並べることができる。
なおここではレーザーアブレーション法により作製を行ったが、イオンビ−ムデポジション（ＩＢＤ）、クラスタ−イオンビ−ムまたはＲＦ、ＤＣ、ＥＣＲ、ヘリコン、ＩＣＰまたは対向タ−ゲットなどのスパッタリング法、ＭＢＥ、イオンプレ−ティング法等のＰＶＤ法や、その他ＣＶＤ、メッキ法あるいはゾルゲル法で作製することができ、限定されない。
【００５７】
その後、実施例１と同様に、二酸化ケイ素からなる絶縁体層及び制御電極となる上部電極を形成し、一般的なリソグラフィー工程を用いて図１に記載した様な構造の電子放射素子を作製した。
【００５８】
以上の様にして作製した電子放射素子を真空槽内に配置し、下部電極（電子供給層）と制御電極との間に制御電極側を正とした電圧を印加し、放射電流量を測定した。その結果、第１の実施形態とほぼ同じ放射電流密度が得られた。
【００５９】
また電子放射層に（Ｌａ，Ｓｒ）Ｏ・２［（Ｌａ，Ｓｒ）ＴｉＯ_３−ｘ］あるいは（Ｌａ，Ｓｒ）Ｏ・３［（Ｌａ，Ｓｒ）ＴｉＯ_３−ｘ］で表される層状ペロブスカイト型材料を配したが、（Ｌａ，Ｓｒ）_２ＴｉＯ_４の場合と同様の放射電流密度が得られた。（Ｌａ，Ｓｒ）Ｏ・２［（Ｌａ，Ｓｒ）ＴｉＯ_３−ｘ］あるいは（Ｌａ，Ｓｒ）Ｏ・３［（Ｌａ，Ｓｒ）ＴｉＯ_３−ｘ］はＫ_２ＮｉＦ_４構造に類似した構造を有し、図６（ｂ）に示す、（Ｒ，Ａ）Ｚ・ｎ［（Ｒ，Ａ）ＭＺ_３−ｘ］で表される結晶構造を有している。電子放射面としてａｂ面が支配的となるように配した場合には、図５（ｂ）のＡＢＺ_３の構造同様に、アルカリ土類金属元素である（Ｓｒ，Ｂａ，Ｃａ）を表面に効率よく並べることができる。
【００６０】
本実施例では、電子放射面としてａｂ面が支配的となるように構成したが、ａｃ面（ｂｃ面）にて配した場合、ａｂ面に対して、得られる放射電流密度に劣化が観測された。このことは結晶構造の異方性を反映したものと考えられ、すなわち結晶化材料が表面に実現されていることの証拠と考えられる。
【００６１】
また同様の作製法により、電子放射層にＮａｘＷＯ_３を用いて電子放射素子を完成させた。０．１５≦ｘ＜１にて作製したＮａｘＷＯ_３は、ブロンズ型構造を有し、ペロブスカイト型に比べ若干歪んだ構造を有するが、第１の実施形態の場合と同様の高い放射電流密度が得られた。なお、Ｄ１ｘＷＯ_３やＤ１ＭｏＯ_３におけるＤ１としてＫ、Ｒｂ、Ｃｓを用いても、また同様の放射電流密度が得られた。
【００６２】
（第４の実施形態）
図２は、第１−第３の実施形態とは別な形態の電子放射素子の概略断面図を示したものである。本電子放射素子の基本的な構成は、図１に示した第１の電子放射素子１１において、制御電極層を直接電子放射層表面に積層したものとなっている。本素子の基材、電子供給層、電子放射層の作製方法は、第１−第３の実施形態に準じ、同様であるので割愛し、本実施形態で用いられる制御電極層について以下に記す。
【００６３】
本実施形態における制御電極層は、電子供給層／電子放射層をへて放射され、放射面に導かれてきた電子をトンネル効果により真空中に放射する必要があることから、その厚さは概ね１０ｎｍ程度である。材質は特に限定されないが、一般的には仕事関数が小さなものが良く、また作製が容易なものが好ましい。これらの観点から本実施形態では、金薄膜を抵抗加熱法によって蒸着した。
【００６４】
また本実施の形態では金薄膜を全面に蒸着したが、電子の透過効率を高めるために金薄膜の一部を微細な穴状パターンで除去しても良い。
【００６５】
得られた電子放射素子を真空槽内に配置し、下部電極（電子供給層）と制御電極の間に制御電極側を正とした電圧を印加し、放射電流量を測定した。その結果、従来の数倍以上である数１０ｍＡ／ｃｍ^２の放射電流密度が得られた。
【００６６】
（第５の実施形態）
第１から第４の実施形態では電子放射素子について説明したが、それらに対向して蛍光体層を有するアノード部を配置することにより、蛍光体発光量を制御可能な蛍光体発光素子を作製することができる。
【００６７】
図３は本実施形態の蛍光体発光素子の概略断面図を示したものである。本蛍光体発光素子は基本的な構成要素として、前記第１の実施形態に記した電子放射素子部とアノード部とそれらを内包する真空容器とからなる。
【００６８】
本蛍光体発光素子において、電子放射素子部の構成はこれに限られず、図２にて示したの実施形態に記載された電子放射素子を用いても良い。
【００６９】
また図の素子構造では、電子放射素子部及びアノード部が真空容器内に完全に含まれているが、このほかにも真空容器の底面部分に直接アノード部を形成しても良いし、また真空容器は用いずに電子放射素子部とアノード部をスペーサーを介して張り合わせ、その空隙部分を真空にしても良い。
【００７０】
アノード部は、電子放射素子から放射された電子を加速するための電圧印加と、蛍光体を発光させる機能を有する領域であり、その構成要素としては、蛍光体層／放射電子に対して加速電圧を印加するアノード電極／前面基材とからなる。このような構成、すなわち前面基材側より発光を取り出す場合、アノード電極として一般的に透明導電膜であるＩＴＯ等が、また前面基材としてガラス等が用いられる。
【００７１】
また蛍光体層に用いられる蛍光体材料としては、ＺｎＯ：ＺｎやＺｎＳ系蛍光体等を所望の発光色に併せて選択すればよい。ただしその選択は、加速される放射電子が持つエネルギー値、すなわちアノード電圧値を考慮して、最も効率の良い蛍光体材料を選ぶことが重要である。
【００７２】
本実施の形態では、アノード部はガラスからなる前面基材にアノード電極として機能する透明導電膜（ＩＴＯ）を積層し、さらに蛍光体層としてＺｎＳ系蛍光体を塗布したものを用いた。
【００７３】
以上の様にして作製した蛍光体発光装置を真空槽内に設置し、下部電極と制御電極の間に制御電極側を正とした電圧を印加して電子放射素子から真空領域に電子を放射させると共に、アノード電極に３ｋＶの加速電圧を印加し、放射電流及び蛍光体発光輝度を測定した。その結果、放射電流密度として数１０ｍＡ／ｃｍ^２が観測され、３００〜４００ｃｄ／ｍ^２の発光輝度が得られた。
【００７４】
（第６の実施形態）
第１から第４の実施形態では、単独の電子放射素子について説明したが、それらを二次元的に複数個配置し、個々の蛍光体発光量を制御することで画像や文字を表示できる画像描画装置に適用できる。
【００７５】
図４は、図１や図２等に示した電子放射素子を二次元的に複数個（この図では、３行×３列＝９個）配置した画像描画装置の断面斜視図である。この構成を用いて画像を描画する方法は、通常マトリックス駆動と呼ばれる方式である。すなわち、基材１上に帯状に形成された電子供給層２となる下部電極と、同様に帯状の放射電流量を制御する制御電極層６となる上部電極とを直交して配置すると共に、それぞれに駆動用ドライバ１８、１９が接続されている。そのそれぞれの駆動ドライバに対して同期信号に併せて画像データを入力すれば、所望の電子放射面（各電極列が直交した個所）より所望の電子放射量で電子を放射させることが可能となる。
【００７６】
故に個々の電子放射素子において、放射電子をアノード電極１４に印加された電圧によって真空内で加速して、蛍光体層１３に照射すれば、任意形状／任意輝度の画像を描画することができる。
【００７７】
（第７の実施形態）
まずＮｂを０．０１ｗｔ％ドープしたＳｒＴｉＯ_３からなる基材の一表面上に電子供給層として金属下部電極を形成した。前記の様に下部電極材料として特に限定はされないが、本実施形態では厚さ２μｍの白金膜を用いた。なお、製膜は４００℃加熱にて行った。電子放射層に用いる材料を下記の要領で作製し、図１０および図１１の冷却素子の作製を行った。
【００７８】
Ｒｂ_ｙＷＯ_３（０．１５≦ｙ＜１）をターゲットとして、レーザーアブレーション法により電子放射層の形成を行った。レーザー光源はＫｒＦエキシマレーザーを用いて、製膜においては、アブレーションエネルギー密度０．１−１０Ｊ／ｃｍ^２、４００−７００℃加熱中、０．１−５００ｍＴｏｒｒ酸素雰囲気中にて行った。作製した電子放射層の厚みはおよそ３００ｎｍとした。なおここではレーザーアブレーション法により作製を行ったが、イオンビ−ムデポジション（ＩＢＤ）、クラスタ−イオンビ−ムまたはＲＦ、ＤＣ、ＥＣＲ、ヘリコン、ＩＣＰまたは対向タ−ゲットなどのスパッタリング法、ＭＢＥ、イオンプレ−ティング法等のＰＶＤ法や、その他ＣＶＤ、メッキ法あるいはゾルゲル法で作製することができ、限定されない。
【００７９】
図１０および図１１は本実施形態の冷却素子の概略断面図を示したものであるが、本素子は基本的な構成要素として、基材および電子供給層および電子放射層アノード電極体と、基体と接した熱源である熱浴と、それらを内包する真空容器とからなる。
【００８０】
本冷却素子において、電子放射を実現するための構成はこれに限られず、図１２に示された構成からなる冷却素子を実現しても良い。
【００８１】
以上の様にして作製した冷却素子を真空槽内に設置し、図１１のように下部電極と制御電極の間に制御電極側を正とした電圧を印加して電子放射素子から真空領域に電子を放射させると共に、アノード電極に３ｋＶの加速電圧を印加し、放射電流及び冷却特性を測定した。その結果、電子放射側とアノード電極体側との間で、放射電流密度として数１０ｍＡ／ｃｍ^２が観測され、数１０℃の温度差が得られた。
【００８２】
またここで示した図の素子構造では、電子放射層及びアノード電極体が真空容器内に完全に含まれているが、このほかにも真空容器の底面部分に直接アノード電極体を形成しても良いし、また反対に基材および電子供給層を真空容器の底面部分に形成しても良い。またあるいは真空容器は用いずに電子放射層とアノード電極体をスペーサーを介して張り合わせ、その空隙部分を真空にしても良い。また放熱効率を向上させるために図１３のようにアノード電極体にフィン状などの放熱体を配しても良い。さらに放熱体に対してファンによる風を当てるのも好ましい。
【００８３】
この際の電子伝導のために、電子放射層とアノード電極体間は、５０ｎｍ以下が好ましい。特に真空を介しての電子伝導による熱輸送のためには、１５ｎｍ以下が熱輸送効率が高く好ましい。
【００８４】
本実施例で得られたような良好な特性は、アルカリ土類金属元素であるＲｂを表面に効率よく配置したことによると考えられる。また、酸化物結晶においては一部酸素欠損を起こす場合が想定されるが、Ｒｂ_ｙＷＯ_３にて０．１５≦ｙ＜１の範囲では同じく良好な特性が得られる。
【００８５】
また電子放射層に（Ｌａ，Ｓｒ）Ｏ・２［（Ｌａ，Ｓｒ）ＴｉＯ_３−ｘ］あるいは（Ｌａ，Ｓｒ）Ｏ・３［（Ｌａ，Ｓｒ）ＴｉＯ_３−ｘ］で表される層状ペロブスカイト型材料を配したが、（Ｌａ，Ｓｒ）_２ＴｉＯ_４の場合と同様の放射電流密度と冷却特性が得られた。
【００８６】
本実施例では、電子放射面としてａｂ面が支配的となるように構成したが、ａｃ面（ｂｃ面）にて配した場合、ａｂ面に対して、得られる放射電流密度に劣化が観測された。このことは結晶構造の異方性を反映したものと考えられ、すなわち結晶化材料が表面に実現されていることの証拠と考えられる。
【００８７】
また同様の作製法により、電子放射層にＮａｘＷＯ_３を用いて電子放射素子を完成させた。０．１５≦ｘ＜１にて作製したＮａｘＷＯ_３は、ブロンズ型構造を有し、ペロブスカイト型に比べ若干歪んだ構造を有するが、第１の実施形態の場合と同様の高い放射電流密度と冷却特性が得られた。なお、Ｄ１ｘＷＯ_３やＤ１ＭｏＯ_３におけるＤ１としてＫ、Ｒｂ、Ｃｓを用いても、また同様の放射電流密度と冷却特性が得られた。
【００８８】
また実施例１および実施例２にて示した電子放射素子において高い電流密度が得られた表１および表２に示した電子放射層の材料を本実施例における冷却素子の電子放射層として用いた場合、いずれの材料を用いた場合も高い放射電流密度と冷却特性が得られた。
【００８９】
（第８の実施形態）
第７の実施の形態にて示した同様の材料構成を用いて、図１４の発電素子の作製を行った。
【００９０】
まずＮｂを０．０１ｗｔ％ドープしたＳｒＴｉＯ_３からなる基材の一表面上に電子供給層として金属下部電極を形成した。前記の様に下部電極材料として特に限定はされないが、本実施形態では厚さ２μｍの白金膜を用いた。なお、製膜は４００℃加熱にて行った。電子放射層に用いる材料を下記の要領で作製した。
【００９１】
Ｒｂ_ｙＷＯ_３（０．１５≦ｙ＜１）をターゲットとして、レーザーアブレーション法により電子放射層の形成を行った。作製は実施例７と同様なのでここでは割愛する。
【００９２】
図１４は本実施形態の冷却素子の概略断面図を示したものであるが、本素子は基本的な構成要素として、基材および電子供給層および電子放射層アノード電極体と、基体と接した熱浴１と、アノード電極体に接した熱浴２と、それらを内包する真空容器とからなる。
【００９３】
本発電素子において、電子放射を実現するための構成はこれに限られず、図１０―１２に示された構成からなる冷却素子に準じた構成を有する発電素子を実現しても良い。
【００９４】
以上の様にして作製した冷却素子を真空槽内に設置し、図１４のように下部電極と制御電極の間に制御電極側を正とした電圧を印加して電子放射素子から真空領域に電子を放射させると共に、約５０℃の温度差を温度（熱浴１）＞温度（熱浴２）の条件下において実現し、電子放射側とアノード電極体側との間での放射電流を測定した。その結果、放射電流密度として数１０ｍＡ／ｃｍ^２が観測され、発電素子動作が確認された。
【００９５】
またここで示した図の素子構造では、電子放射層及びアノード電極体が真空容器内に完全に含まれているが、このほかにも真空容器の底面部分に直接アノード電極体を形成しても良いし、また反対に基材および電子供給層を真空容器の底面部分に形成しても良い。
【００９６】
本実施例で得られたような良好な特性は、アルカリ土類金属元素であるＲｂを表面に効率よく配置したことによると考えられる。また、酸化物結晶においては一部酸素欠損を起こす場合が想定されるが、Ｒｂ_ｙＷＯ_３にて０．１５≦ｙ＜１の範囲では同じく良好な特性が得られる。
【００９７】
また電子放射層に（Ｌａ，Ｓｒ）Ｏ・２［（Ｌａ，Ｓｒ）ＴｉＯ_３−ｘ］あるいは（Ｌａ，Ｓｒ）Ｏ・３［（Ｌａ，Ｓｒ）ＴｉＯ_３−ｘ］で表される層状ペロブスカイト型材料を配したが、（Ｌａ，Ｓｒ）_２ＴｉＯ_４の場合と同様の放射電流密度と冷却特性が得られた。
【００９８】
本実施例では、電子放射面としてａｂ面が支配的となるように構成したが、ａｃ面（ｂｃ面）にて配した場合、ａｂ面に対して、得られる放射電流密度に劣化が観測された。このことは結晶構造の異方性を反映したものと考えられ、すなわち結晶化材料が表面に実現されていることの証拠と考えられる。
【００９９】
また同様の作製法により、電子放射層にＮａｘＷＯ_３を用いて電子放射素子を完成させた。０．１５≦ｘ＜１にて作製したＮａｘＷＯ_３は、ブロンズ型構造を有し、ペロブスカイト型に比べ若干歪んだ構造を有するが、第１の実施形態の場合と同様の高い放射電流密度と冷却特性が得られた。なお、Ｄ１ｘＷＯ_３やＤ１ＭｏＯ_３におけるＤ１としてＫ、Ｒｂ、Ｃｓを用いても、また同様の放射電流密度と冷却特性が得られた。
【０１００】
また実施例１および実施例２にて示した電子放射素子において高い電流密度が得られた表１および表２に示した電子放射層の材料を本実施例における冷却素子の電子放射層として用いた場合、いずれの材料を用いた場合も高い放射電流密度と冷却特性が得られた。
【０１０１】
（第９の実施形態）
本実施形態では、第８の実施形態にて示した冷却素子構造を二次元的に複数個配置してなる冷却パネルを作製した。
【０１０２】
図１５は、図１０や図１１、図１２等に示した冷却素子を二次元的に複数個配置してなる冷却素子の断面斜視図である。通常マトリックス駆動と呼ばれる方式を用いて、基材上に帯状に形成された電子供給層となる下部電極と、同様に帯状の放射電流量を制御する制御電極層となる上部電極とを直交して配置すると共に、それぞれに駆動用ドライバが接続された構造を実現することで、それぞれの駆動ドライバに対して同期信号に併せてデータを入力すれば、所望の位置の冷却度を調節することが可能となる。また熱浴の温度分布をデータとしてフィードバック入力することで冷却パネル全体の均熱化などを実現することが可能となる。この構成を用いて冷却素子を実現すれば、大面積の冷却パネルを簡便に実現することができる。
【０１０３】
故に個々の冷却素子において、放射電子をアノード電極に印加された電圧によって真空内で加速させることで、任意形状／任意温度の冷却用パネルを実現することができる。
（第１０の実施形態）
第１―第９の実施形態にて、電子放射を行う領域として真空を用いたが、真空を絶縁体層として配する場合、真空環境下にて、電子放射層とアノード部との間の距離を調整して近づければよい。距離の制御には、圧電体などを用いて行うことができる。
【０１０４】
また別な形態として、真空以外の絶縁体として、アモルファス体、あるいは微結晶体を用いるのが好ましい。ここでいう微結晶体とは結晶径が１０ｎｍ以下でアモルファス体中に分散したものを指す。またあるいは絶縁体として無機高分子材料を用いるのが好ましい。無機高分子材料の中でも、シリケート、アルミシリケート材料を母体とする多孔性無機高分子が好ましい。
【０１０５】
ここでいう多孔質体とは、連続空孔または独立空孔を有した固体物質のことであり、母材粉体の成形、粉体焼成、化学発泡、物理発泡、ゾル−ゲル法などの方法で作製することができる。本発明の電子放射素子においては、多孔質体としてナノメートルサイズの空孔を多数有することが好ましい効果が得られる。
【０１０６】
図１６は、絶縁体として用いる微細な構造を模した概略模式図であり、骨格を構成する多孔質体状の母材からなっている。多孔質構造は、大きさが数ｎｍ程度の粒子で三次元ネットワーク的に構成される固体骨格部で固体としての形状は保ちながら、大きさが数１０ｎｍ程度の連続空孔（気相）を多数含んだ状態である。また場合によって、さらに空孔と同程度、あるいはそれ以下の大きさの粒子状電子放射材が分散配置されている。すなわち電極体間に対する印加電圧によって、絶縁体の多孔質構造を形成する固体骨格部分に電界集中する結果、電子放出体より効率的に電子が絶縁体内へ送られる共に、電子がアノード電極体へ向けて放射伝達される。この電子供給に関する電界集中効果は、絶縁体の構成母材を多孔質構造としたことにより顕著となり、電子放射層とアノード電極体との間の電子の伝達が効率的に可能になる。
【０１０７】
以上の原理において、当然のことながら、供給電子の一部は、多孔質体の固相成分によって散乱され、エネルギーを失うものもあるが、固相領域の大きさが数ｎｍ程度であるため、大部分の電子を熱伝達成分として用いることが可能となる。
【０１０８】
また同様に、電子放射層から放射された電子の一部は、再び多孔質体の固相成分によって散乱されるが、再び電子放射材に伝達されることで電子放射可能となる。
【０１０９】
このような気相を多く含む構造を有する多孔質構造として、ゾル−ゲル法によって作られる乾燥ゲルを特に候補として用いることができる。ここで乾燥ゲルとは、大きさが数〜数１０ｎｍ程度の粒子で構成される固体骨格部を持ち、平均空孔径が１００ｎｍ以下の範囲である連続空孔が形成されているナノ多孔質体である。またその材質として、電界集中効果の高い比較的高抵抗な電気特性を示す半導体材料及び絶縁体材料が適当であり、中でも多孔質シリカ（多孔質酸化ケイ素）が好適である。そこでこの好適例である多孔質シリカを例に多孔質からなる第１絶縁体の作製方法について説明する。
【０１１０】
本発明で用いる乾燥ゲルからなる多孔質シリカを得る方法は、大きく湿潤ゲルを得る工程と、それを乾燥する工程からなる。
【０１１１】
まず湿潤ゲルは、溶媒中に混合したシリカの原料をゾル−ゲル反応させることによって合成できる。このとき必要に応じて触媒を用いる。この形成過程では、溶媒中で原料が反応しながら微粒子を形成し、その微粒子がネットワーク化して網目状骨格を形成する。具体的には、所定の空孔度合の多孔質シリカが得られる様に固体成分である原料及び溶媒の組成を決定する。その組成に調合した溶液に対して、必要に応じて触媒や粘度調整剤などを添加して撹拌し、塗布などによって所望の使用形態にする。塗布方法については、膜厚やその形状等によって変化するので限定はされないが、スピンコート法やディップ法、スクリーン印刷法などを用いることができる。
【０１１２】
この状態で一定時間経過させることで溶液はゲル化し、シリカ湿潤ゲルが得られる。製造時の温度条件としては、通常の作業温度である室温近傍で行なえるが、必要に応じて溶媒の沸点以下の温度まで加熱することもある。
【０１１３】
シリカの原料としては、テトラメトキシシラン、テトラエトキシシラン、トリメトキシメチルシラン、ジメトキシジメチルシラン等のアルコキシシラン化合物、これらのオリゴマー化合物、またケイ酸ナトリウム（ケイ酸ソーダ）、ケイ酸カリウム等の水ガラス化合物等、またコロイダルシリカ等を単独あるいは混合して用いることができる。
【０１１４】
溶媒としては、原料が溶解してシリカ形成できれば良く、水やメタノール、エタノール、プロパノール、アセトン、トルエン、ヘキサンなどの一般的な有機溶媒を単独あるいは混合して用いることができる。
【０１１５】
触媒としては、水や塩酸、硫酸、酢酸などの酸や、アンモニア、ピリジン、水酸化ナトリウム、水酸化カリウムなどの塩基を用いることができる。
【０１１６】
粘度調整剤としては、エチレングリコール、グリセリン、ポリビニルアルコール、シリコーン油などを用いることができるが、湿潤ゲルを所定の使用形態にできるのであれば、これらに限られるものではない。
【０１１７】
なお上記では、母材となる多孔質体のみの形成方法について説明したが、多孔質体形成と同時に粒子状電子放射材を分散させる手法としては、ゾル−ゲル反応溶媒中に適宜電子放射材粒子を混合しておき、ゲル化することでも作製できる。
【０１１８】
次に湿潤ゲルから乾燥ゲルを得る乾燥工程について記す。
【０１１９】
乾燥工程には、自然乾燥、加熱乾燥、減圧乾燥の通常乾燥法や、超臨界乾燥法、凍結乾燥法などを用いることができる。しかしながら一般に、通常乾燥法では溶媒蒸発時のストレスによって多孔質体が収縮してしまう。よって、乾燥ゲルを形成する方法としては、超臨界乾燥を本発明では好ましく用いることができる。また湿潤ゲルの固体成分表面を撥水処理等して、乾燥時のゲル収縮を防ぐこともできる。
【０１２０】
この超臨界乾燥に用いる溶媒は、湿潤ゲルの溶媒を用いることができる。また必要に応じて、超臨界乾燥において扱いやすい溶媒に置換しておくことが好ましい。置換する溶媒としては、超臨界流体として用いるメタノール、エタノール、イソプロピルアルコールなどのアルコール類や二酸化炭素、水などが挙げられる。またこれらの超臨界流体に溶出しやすいアセトン、酢酸イソアミル、ヘキサンなど一般的に取り扱い易い有機溶剤に置換しておいても良い。
【０１２１】
超臨界乾燥条件としては、オートクレーブなどの圧力容器中で行ない、例えばメタノールではその臨界条件である圧力８．０９ＭＰａ、温度２３９．４℃以上にし、温度一定の状態で圧力を徐々に開放して乾燥を行なう。また二酸化炭素の場合は、臨界圧力７．３８ＭＰａ、臨界温度３１．１℃以上にして、同じように温度一定の状態で超臨界状態から圧力を徐々に開放して乾燥を行なう。また水の場合は、臨界圧力２２．０４ＭＰａ、臨界温度３７４．２℃以上にして乾燥を行なう。乾燥に必要な時間としては、超臨界流体によって湿潤ゲル中の溶媒が１回以上入れ替わる時間以上を経過すればよい。
【０１２２】
湿潤ゲルを撥水処理してから乾燥する方法は、撥水処理のための表面処理剤を湿潤ゲルの固体成分表面に化学反応させる。これによって湿潤ゲルの網目構造の空孔内に発生する表面張力を低減し、通常乾燥時に発生する収縮を抑制することができる。
【０１２３】
表面処理剤としては、トリメチルクロルシラン、ジメチルジクロルシランなどのハロゲン系シラン処理剤やトリメチルメトシシラン、トリメチルエトキシシランなどのアルコキシ系シラン処理剤、ヘキサメチルジシロキサン、ジメチルシロキサンオリゴマーなどのシリコーン系シラン処理剤、ヘキサメチルジシラザンなどのアミン系シラン処理剤、プロピルアルコール、ブチルアルコールなどのアルコール系処理剤などを用いることができるが、同様の効果が得られるものならばこれらの表面処理剤に限られるものではない。
【０１２４】
なお本方法で得られる乾燥ゲルの材質としては、シリカのみではなく他の無機材料や有機高分子材料などを用いることもできる。無機酸化物の乾燥ゲルの固体骨格部は、シリカ（酸化ケイ素）または酸化アルミニウム（アルミナ）などゾル−ゲル反応で得られる一般的なセラミックスを成分として適用することができる。
【０１２５】
以上は真空部の代わりとしての絶縁体を構成する多孔性無機高分子材の形成方法について記したが、以上述べた多孔性無機高分子を図３の蛍光体発光素子に適用し、評価を行ったところ第５の実施の形態での同程度の高い放射電流密度と発光特性結果が得られた。
【０１２６】
また、以上述べた多孔性無機高分子を図１１の冷却素子に適用し、評価を行ったところ第７の実施の形態での同程度のの高い放射電流密度と冷却特性結果が得られた。
【０１２７】
【発明の効果】
本発明によれば、基材と、電子を供給する導電性あるいは半導電性の電子供給層と、電子を放射する電子放射層と、電圧印加によって放射電子量を制御する制御電極層とを備えて構成された電子放射素子において、電子放射層としてアルカリ金属あるいはアルカリ土類金属を含む酸化物結晶材料を用いることにより、安定的な低仕事関数の表面を実現し、高効率な電子放射を実現できる。
【０１２８】
また本発明の電子放射素子と、蛍光体層を備えたアノード部を構成要素に持ち、電子放射素子を二次元状に複数個配列すると共に、電子放射素子からの電子放射量によって個々の蛍光体発光量を個別に制御することで画像描画装置を実現できる。
【０１２９】
さらに基材と、電子を供給する導電性あるいは半導電性の電子供給層と、電子を放射する電子放射層と、電圧印加によって放射電子量を制御する制御電極層とを備え、電圧印可によって基材の冷却を高効率な冷却素子を実現する。また基材あるいは電子供給層と制御電極層との間に温度差を設けることで、両層の間に電流を流れさしめる高効率で従来にない発電素子を実現できる。
【図面の簡単な説明】
【図１】本実施形態の電子放射素子の断面構成図
【図２】第１−第３の実施形態とは別な形態の電子放射素子の概略断面図
【図３】本実施形態の蛍光体発光素子の概略断面図
【図４】電子放射素子を二次元的に複数個配置した画像描画装置の断面斜視図
【図５】ペロブスカイト型結晶構造ＡＢＺ_３を示す図
【図６】ペロブスカイト型類縁結晶構造Ｋ２ＮｉＦ４および（Ｒ，Ａ）Ｚ・ｎ［（Ｒ，Ａ）ＭＺ_３−ｘ］を示す図
【図７】従来のスピント型のＦＥ型電子放射素子の例の断面構造図
【図８】従来のＭＩＭ／ＢＳＤ型のＦＥ型電子放射素子の例の断面構造図
【図９】非特許文献１に示された冷却素子を示す図
【図１０】本発明に係る冷却素子を示す図
【図１１】本発明に係る冷却素子を示す図
【図１２】本発明に係る冷却素子を示す図
【図１３】アノード電極体にフィン状などの放熱体を配した本発明に係る冷却素子を示す図
【図１４】本発明に係る発電素子を示す図
【図１５】本発明に係る冷却素子を二次元的に複数個配置してなる冷却素子の断面斜視図
【図１６】絶縁体として用いる微細な構造を模した概略模式図
【符号の説明】
１：基材
２：電子供給層
６：制御電極層
１３：蛍光体層
１４：アノード電極
１８：駆動用ドライバ
１９：駆動用ドライバ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electron emitting element having an electron emitting layer for controlling electron emission, an image drawing apparatus and a cooling element / power generating element using the electron emitting element.
[0002]
[Prior art]
As a phenomenon of electron emission from a solid, there is a thermionic emission that emits electrons using thermal energy. In recent years, a cold cathode type micro electron emitting element (cold cathode emitter) which does not require heating has been attracting attention. I have. The principle of the cold cathode type emitter is to tunnel electrons through application of an electric field and to extract the electrons from the solid surface into a vacuum, which is called field emission (FE). As the FE type emitter, for example, a Spindt type, a MIM (Metal-Insulator-Metal) type, a BSD (Ballistic Electron Surface-Emitting Display) type and the like are reported. The Spindt-type electron-emitting device is disclosed in Patent Document 1 or the like, and its operation is performed at the tip of a small conical emitter formed of a high melting point metal material such as silicon (Si) or molybdenum (Mo). High electric field (> 1 × 10 ⁹ V / m), electrons are emitted into a vacuum. Further, the MIM type has a structure in which a very thin insulator layer is sandwiched between a pair of metal electrode layers (metal-insulator layer-metal). The electron which tunneled the layer is emitted into a vacuum.
[0003]
The BSD type basically has the same principle as the MIM type as described in Patent Document 2 and the like, but uses porous polysilicon for a solid layer in which electrons are tunneled. FIGS. 7 and 8 show cross-sectional structures of a Spindt type (Comparative Example 1) and a MIM / BSD type (Comparative Example 2) as examples of the FE-type electron emitting element as described above. As shown in the drawing, the Spindt-type element 71 mainly includes a substrate 71, a lower electrode 72 for supplying electrons, a cone-shaped electron emitting portion 73, and a control electrode 76. In this case, the voltage is applied to the control electrode 76 so that electrons are emitted from the distal end into a vacuum due to the effect of electric field concentration generated at the distal end of the cone-shaped electron emitting section 73. That is, the electrons supplied from the lower electrode 72 are conducted inside the solid of the electron emitting portion 73, reach the tip which is the electron emitting portion, and are emitted therefrom into a vacuum. MIM / BSD type device 81 Is composed of a base material 81, a lower electrode 82, an electron tunnel layer 83, and a control electrode 86. In this case, due to the effect of the electric field generated by the voltage applied to the control electrode 86, electrons supplied from the lower electrode 82 are tunnel-transmitted through the electron tunnel layer 83 and emitted from the surface of the control electrode 86 into a vacuum. That is, the electrons supplied from the lower electrode 82 are conducted through the inside of the solid of the electron tunnel layer 83, reach the surface which is the electron emission portion, and are emitted therefrom into a vacuum.
[0004]
On the other hand, cooling techniques for transporting heat can be broadly classified into those using a compressor realized by refrigerant compression and those using a thermoelectric phenomenon. Compressors have high efficiency and are used in many refrigerators, and are also used in refrigerators and air conditioners as consumer equipment. However, most of the refrigerants used are mainly chlorofluorocarbons, and problems have been pointed out with respect to environmental friendliness. Alternatives other than CFCs are being considered, but no refrigerant has surpassed CFCs. On the other hand, devices using thermoelectric phenomena realize cooling with no refrigerant, not only giving a large solution to environmental friendliness, but also making it possible to make machine-free and maintenance-free ideal solid-state elements. And the ripple effect is immeasurable. However, the efficiency is low, and it is not used for refrigerators and air conditioners except for a part. It is said that the Carnot efficiency from -25 ° C to + 25 ° C at the operating temperature of refrigerators is about 30-50%, but Peltier devices using thermoelectric phenomena are less than 10%, which poses a major material problem. Have The thermoelectric phenomenon is a phenomenon that realizes heat transfer by electrons, thereby enabling cooling and power generation. The thermoelectric phenomenon is generally given a thermoelectric index ZT, which indicates that higher efficiency can be obtained by improving ZT. ZT is σS ² It is expressed by T / κ, and indicates that the electron transporting properties greatly contribute to the thermoelectric properties. In that sense, the thermoelectric function described by a phenomenon in which electrons drift-conduct in a material has its function size determined by a state such as electron density.
[0005]
In recent years, a report has been made to utilize thermionic emission phenomenon of emitting electrons using thermal energy for cooling (Non-Patent Document 1). As a conventional example, as shown in FIG. 9, an electron emitting electrode body and an electrode body facing the electron emitting electrode body are arranged with a slight vacuum gap therebetween, and a part of the electron emitting electrode body is brought into contact with a heat bath, By applying a voltage between the electrodes, the heat of the heat bath is transmitted to the other electrode side due to thermionic emission phenomenon between the two electrodes to perform cooling. At the same time, by providing a temperature difference between the two electrodes, a current can flow between the electrodes, which can be realized as a power generating element.
[0006]
However, unlike a heat engine such as a compressor, the realization of the function of a heat-related solid element is largely lacking, and no promising element other than the Peltier element described above has been found at present. In the realization of active devices such as thermal solid-state switching devices, there is no demonstration example. By realizing thermoelectric elements and switch elements together with existing passive bodies / elements such as heat conductors, heat insulators, and heating elements, it is possible to realize thermosolid circuit elements that can be considered from the analogy with electric circuit elements. Become. The realization of a thermal switch requires efficient control of the electrons that transport heat.
[0007]
The electron emission phenomenon, which is the basic principle of these technologies, largely depends on the work function of the electrode on the electron emission surface, and electrons are easily emitted by approaching a vacuum level, that is, have a smaller work function. Has been found to be preferable.
[0008]
[Patent Document 1]
U.S. Pat. No. 3,665,241
[Patent Document 2]
JP-A-8-250766
[Non-patent document 1]
G. FIG. D. Mahan et al., Journal of Applied Physics 76, p. 4362-P. 4366 (1994)
[0009]
[Problems to be solved by the invention]
The above-mentioned Spindt-type electron-emitting device is based on the principle that electrons are emitted by the electric field concentration effect on the tip of a cone-shaped structure formed by making full use of the semiconductor process, so its characteristics are very sensitive to the tip shape and surface condition. Affect. Also, due to the process, it is difficult to form a large area.
[0010]
Further, since the MIM / BSD type electron emitting element is based on the principle that electrons supplied from the lower electrode are transmitted through the tunnel and emits electrons, it is necessary to control the film thickness and film quality of the electron tunnel layer.
[0011]
That is, in the conventional electron-emitting device, there are problems that it is difficult to manufacture the device over a large area and that the device manufacturing process needs to be performed with good controllability.
[0012]
Also, a cooling / power generation element composed of two opposing electrodes is suitable for a large area process, but in order to realize electron emission, it is necessary to realize a highly efficient electron emission surface on the electrode body.
[0013]
In order to achieve high efficiency electron emission, a material having a small work function is required.However, the use of an alkali metal or an alkaline earth metal to realize a small work function is not stable due to low stability. Uses other than cesium are rare.
[0014]
The present invention provides a base material made of an oxide crystal containing an alkali metal or an alkaline earth metal as an electron emission layer disposed on the electrode body surface in order to realize highly efficient electron emission by a relatively easy method. An object of the present invention is to provide an electron emission element, an image drawing apparatus, a cooling element, and a power generation element, which have not existed conventionally, by using a material configuration using the above.
[0015]
[Means for Solving the Problems]
The present invention as a means for solving the problem,
A base material, a conductive or semiconductive electron supply layer that is provided on the base material and supplies electrons, and an electron emission layer that emits electrons supplied from the electron supply layer thereon, and an electron emission layer. A control electrode layer that is arranged through a space and controls the amount of radiated electrons by applying a voltage, in the electron emitting element, by using a crystal material containing an alkali metal or an alkaline earth metal as the electron emitting layer. , Realize a stable low work function surface and realize high efficiency electron emission.
[0016]
The electron emitting element of the present invention and an anode section provided with a phosphor layer as constituent elements, a plurality of electron emitting elements are arranged two-dimensionally, and individual phosphors are determined by the amount of electron emission from the electron emitting element. An image drawing apparatus can be realized by individually controlling the light emission amount.
[0017]
A base material, a conductive or semiconductive electron supply layer provided on the base material for supplying electrons, an electron emission layer for emitting electrons supplied from the electron supply layer thereon, and an electron emission layer And a control electrode layer arranged through a space to control the amount of emitted electrons by applying a voltage, wherein the cooling element that cools the substrate by applying a voltage includes an alkali metal or an alkaline earth metal as an electron emitting layer. By using a crystalline material, a stable surface with a low work function is realized, and a highly efficient cooling element is realized by using highly efficient electron emission.
[0018]
A base material, a conductive or semiconductive electron supply layer provided on the base material for supplying electrons, an electron emission layer for emitting electrons supplied from the electron supply layer thereon, and an electron emission layer And a control electrode layer that is arranged via a space and controls the amount of radiated electrons by applying a voltage, and by providing a temperature difference between the base material or the electron supply layer and the control electrode layer, between the two layers. By using a crystal material containing an alkali metal or an alkaline earth metal as the electron emitting layer in a power generating element that allows a current to flow, a high-efficiency power generating element can be realized.
[0019]
The crystal material for this purpose is the chemical formula AMZ _3-x Is preferably used as a base material. Here, A is at least one of Ca, Sr, Ba, Li, Na, K, and Rb, and M is Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Zr, Nb, Mo includes at least one of Mo, Ru, Ta, and Ir, Z includes at least one of O, N, and F, and x indicates a range of 0 ≦ x ≦ 1.
[0020]
Alternatively or as a crystalline material, the chemical formula AMZ _3-x Formula (R, A) MO in which part of the A site is replaced with the R element _3-x Is preferably used as a base material. Here, R includes Y, at least one of the elements of element numbers 57 to 71, A at least one of Ca, Sr, and Ba, and M represents Ti, V, Cr, Mn, Fe, Co, At least one of Ni, Cu, Zn, Ga, Zr, Nb, Mo, Ru, and Ta is included, Z includes at least one of O, N, and F, and x is 0 ≦ x ≦ 1. Indicates the range.
[0021]
Alternatively, the crystal material has the chemical formula (R, A) ₂ MZ _4-x Is preferably used as a base material. Here, R includes Y, at least one of the elements of element numbers 57 to 71, A at least one of Ca, Sr, and Ba, and M represents Ti, V, Cr, Mn, Fe, Co, It is preferable to include at least one of Ni, Cu, Zn, Ga, Zr, Nb, Mo, Ru, and Ta. Z includes at least one of O, N, and F, and x indicates a range of 0 ≦ x ≦ 1.
[0022]
Alternatively, as a crystal material, the chemical formula (R, A) Zn ((R, A) MZ _3-x ] Is preferably used as a base material. Here, R includes Y, at least one of the elements of element numbers 57 to 71, A at least one of Ca, Sr, and Ba, and M represents Ti, V, Cr, Mn, Fe, Co, At least one of Ni, Cu, Zn, Ga, Zr, Nb, Mo, Ru, and Ta is included, Z includes at least one of O, N, and F, and x is 0 ≦ x ≦ 1. Indicates the range.
[0023]
Alternatively, the crystal material is represented by the chemical formula D1. _y WO _3-x Is preferably used as a base material. Here, D1 includes at least one of Li, Na, K, Rb, Cs, Mg, Ca, Sr, and Ba, and y indicates a range of 0.15 ≦ y <1. X indicates a range of 0 ≦ x ≦ 1.
[0024]
BEST MODE FOR CARRYING OUT THE INVENTION
The electron emitting element, the phosphor light emitting element, the image drawing apparatus, and the cooling element / power generating element of the present invention will be described with reference to the drawings.
[0025]
FIG. 1 shows a cross-sectional configuration diagram of the electron-emitting device of the present embodiment. This electron-emitting device applies a voltage (control power supply) for electron emission via a substrate, an electron supply layer that supplies emitted electrons, an electron-emitting layer that emits electrons, and an insulator layer as basic components. And a control electrode layer. The electron emission layer uses a crystallized material containing an alkali metal or an alkaline earth metal as a base material. Details will be described later together with specific examples.
[0026]
As a substrate, a glass substrate is generally used. However, the present invention is not limited to this, and another insulating base material (such as a ceramic substrate) may be used. It is also possible to use a conductive substrate such as a low-resistance silicon substrate or a metal substrate without using an insulating substrate, and in this case, the function of the electron supply layer can be added to the conductive substrate. .
[0027]
The electron supply layer preferably has a structure in which a metal material such as aluminum, titanium, chromium, nickel, copper, gold, and tungsten, or a low-resistance n-type semiconductor made of silicon, silicon carbide, gallium nitride, or the like is stacked with a metal. However, there is no particular limitation as long as it has a function / function as this layer, that is, a structure / material capable of supplying electrons to the electron emitting layer. Further, in order to stabilize the emission current, a structure in which the electron supply layer and the resistive film are stacked may be used as the electron supply layer. Note that the thickness of the electron supply layer is generally about 1 to 50 μm.
[0028]
The electron emitting layer in the present electron emitting element has a function of emitting transmitted electrons into a vacuum due to an electric field generated by a voltage applied to the control electrode layer. Materials and materials having a small work function (electron affinity) value are preferable because they exhibit excellent characteristics. However, there are few stable materials that can easily achieve such interface characteristics. In the present invention, it has been found that a good and stable electron emitting layer can be provided by using a material made of a crystallized material containing an alkali metal or an alkaline earth metal as a base material. More specifically, it is preferable to use a perovskite type crystal having the chemical formula described in the claims, or a crystallized material such as an analog or bronze type thereof.
[0029]
In order to realize highly efficient electron emission, a material having a small work function is necessary. However, the use of a compound containing an alkali metal D1 or an alkaline earth metal A for achieving a small work function is not stable. Use of other than cesium oxide is rare. However, when cesium oxide is used as the electron emitting layer, cesium alone is oxidized, or when cesium oxide is directly disposed, a small work function surface is provided with good reproducibility and excellent surface flatness. It was difficult.
[0030]
Therefore, in the present invention, the AMZ _3-x And (R, A) MO _3-x Or (R, A) ₂ MZ _4-x , (R, A) Zn [(R, A) MZ _3-x ] Or D1 _y WO _3-x It can be understood that a stable and flat crystal surface can be realized in the crystal plane [(A or D1)-(O or N or F)] obtained by using the crystal material having the material represented by Was.
[0031]
In other words, with a material configuration using a base material made of an oxide crystal containing an alkali metal or an alkaline earth metal, it is possible to provide a non-conventional electron emitting element and an image drawing apparatus, a cooling element, and a power generating element using the same. it can.
[0032]
Here, by using a crystallization material as the electron emitting layer, an alkali metal or alkaline earth metal element can be efficiently arranged. A surface composed of an alkali metal or alkaline earth metal element has been realized, and more stable by controlling the atmosphere on the surface so that the O, N, and F elements are more deficient than the alkali metal or alkaline earth metal element. Thus, an electron emission surface having a lower work function can be controlled and manufactured.
[0033]
Further, since it is realized as a crystal surface, it also has surface flatness suitable for uniform electron emission, and is suitable for realizing an extremely thin vacuum insulating layer.
[0034]
The control electrode layer is a layer having a function of applying an electric field to an electron emitting layer or the like by applying a voltage and controlling the amount of emitted electrons by its intensity. The metal is not particularly limited as long as it is a metal having a good workability such as. In general, aluminum, nickel, or the like is preferably used as a material having the above-described characteristics.
[0035]
Hereinafter, examples of specific embodiments of the electron emitting element, the image drawing apparatus, the cooling element, and the power generating element according to the present invention will be described.
[0036]
(1st Embodiment)
First, a basic electron emitting element will be described with reference to FIG.
[0037]
First, a metal lower electrode was formed as an electron supply layer on one surface of a substrate made of silicon. Although the lower electrode material is not particularly limited as described above, a platinum film having a thickness of 2 μm is used in this embodiment. The film was formed by heating at 400 ° C.
[0038]
On top of that, (Sr, Ba, Ca) TiO ₃ Was used as a target to form an electron emitting layer by a sputtering method. Sputtering is performed at a temperature of 400-650 ° C. while heating in a mixed gas atmosphere of 0.1-500 mTorr (Ar / O ₂ = 0.1-10) The thickness of the electron-emitting layer fabricated in the middle was about 300 nm. In this case, the fabrication was performed by the sputtering method. However, pulse laser deposition (PLD), ion beam deposition (IBD), cluster ion beam or RF, DC, ECR, helicon, ICP, or an opposing target. It can be manufactured by a PVD method such as a sputtering method, an MBE, an ion plating method or the like, or other CVD, a plating method or a sol-gel method, and is not limited.
[0039]
Used (Sr, Ba, Ca) TiO ₃ Has a perovskite-type crystal structure, and a structure as shown in FIG. In addition, as shown in FIGS. 5B to 5D, by providing the electron emission surface in various plane orientations such as the (100) plane, the (110) plane, and the (111) plane, in any case, Alkaline earth metal elements (Sr, Ba, Ca) can be efficiently arranged on the surface.
[0040]
A stable electron emission layer can be realized by realizing the surface of the alkaline earth metal-oxygen having the crystal arrangement.
[0041]
Thereafter, an insulator layer made of silicon dioxide and an upper electrode serving as a control electrode were formed, and an electron-emitting device having a structure as shown in FIG. 1 was manufactured using a general lithography process.
[0042]
The electron-emitting device manufactured as described above was placed in a vacuum chamber, and a voltage with the control electrode side being positive was applied between the lower electrode (electron supply layer) and the control electrode, and the amount of emission current was measured. . As a result, several tens mA / cm, which is several times higher than the conventional one, ² Was obtained. It is considered that such good characteristics are due to the efficient arrangement of (Sr, Ba, Ca), which is an alkaline earth metal element, on the surface. In addition, it is assumed that oxygen deficiency may partially occur in the oxide crystal, but (Sr, Ba, Ca) TiO _3-x In the range of 0 ≦ x ≦ 1, similarly good characteristics can be obtained.
[0043]
Table 1 shows the case where another material is used for the electron emission layer. In each of the cases described above, higher emission current densities were obtained than in the conventional case. Here, x is in the range of 0 ≦ x ≦ 1, and the same radiation current density was obtained with respect to the change of x in the oxide target serving as the base material.
[0044]
[Table 1]

[0045]
(Second embodiment)
When manufacturing an electron-emitting device having the same structure as that of the first embodiment, the material used for the electron-emitting layer was manufactured in another form, and the electron-emitting device of FIG. 1 was manufactured.
[0046]
First, SrTiO doped with 0.01 wt% of Nb was used as a basic electron emitting element. ₃ A metallic lower electrode was formed as an electron supply layer on one surface of a substrate made of. Although the lower electrode material is not particularly limited as described above, in the present embodiment, SrRuO ₃ Was used. The film was formed by heating at 550 ° C. by a sputtering method.
[0047]
On top of that, (La, Sr) TiO ₃ Was used as a target to form an electron-emitting layer by a laser ablation method. As a laser light source, a KrF excimer laser is used. In the film formation, an ablation energy density is 0.1-10 J / cm. ² The heating was performed at a temperature of 400 to 700 ° C. in an oxygen atmosphere of 0.1 to 500 mTorr. The thickness of the manufactured electron emission layer was about 300 nm. In this case, the laser beam ablation method was used, but ion beam deposition (IBD), cluster ion beam or sputtering method such as RF, DC, ECR, helicon, ICP or opposed target, MBE, ion pre- It can be produced by a PVD method such as a plating method, other CVD, a plating method or a sol-gel method, and is not limited.
[0048]
Thereafter, an insulator layer made of silicon dioxide and an upper electrode serving as a control electrode were formed in the same manner as in Example 1, and an electron-emitting device having a structure as shown in FIG. 1 was manufactured using a general lithography process. .
[0049]
The electron-emitting device manufactured as described above was placed in a vacuum chamber, and a voltage with the control electrode side being positive was applied between the lower electrode (electron supply layer) and the control electrode, and the amount of emission current was measured. . As a result, a radiation current density almost the same as that of the first embodiment was obtained.
[0050]
Table 2 shows the case where another material is used for the electron emission layer. In each case, as in Example 1, a higher emission current density was obtained as compared with the related art.
[0051]
[Table 2]

[0052]
Further, also in the case shown in Table 3 when used in the electron emission layer, a higher emission current density was obtained as compared with the conventional case.
[0053]
[Table 3]

[0054]
(Third embodiment)
When manufacturing an electron-emitting device having the same structure as that of the first embodiment, the material used for the electron-emitting layer was manufactured in another form, and the electron-emitting device of FIG. 1 was manufactured.
[0055]
First, SrTiO doped with 0.01 wt% of Nb was used as a basic electron emitting element. ₃ A metallic lower electrode was formed as an electron supply layer on one surface of a substrate made of. Although the lower electrode material is not particularly limited as described above, in the present embodiment, SrRuO ₃ Was used. The film was formed by heating at 550 ° C. by a sputtering method.
[0056]
On top of that, (La, Sr) ₂ TiO ₄ Was used as a target to form an electron-emitting layer by a laser ablation method. As a laser light source, a KrF excimer laser is used. In the film formation, an ablation energy density is 0.1-10 J / cm. ² The heating was performed at a temperature of 400 to 700 ° C. in an oxygen atmosphere of 0.1 to 500 mTorr. The thickness of the manufactured electron emission layer was about 300 nm. Made (La, Sr) ₂ TiO ₄ Are arranged such that the ab plane is dominant as the electron emission plane. (La, Sr) ₂ TiO ₄ Is K ₂ NiF ₄ It is a substance having a structure, and has a crystal structure shown in FIG. ABZ in FIG. ₃ (Sr, Ba, Ca), which is an alkaline earth metal element, can be efficiently arranged on the surface.
In this case, the laser beam ablation method was used, but ion beam deposition (IBD), cluster ion beam or sputtering method such as RF, DC, ECR, helicon, ICP or opposed target, MBE, ion pre- It can be produced by a PVD method such as a plating method, other CVD, a plating method or a sol-gel method, and is not limited.
[0057]
Thereafter, an insulator layer made of silicon dioxide and an upper electrode serving as a control electrode were formed in the same manner as in Example 1, and an electron-emitting device having a structure as shown in FIG. 1 was manufactured using a general lithography process. .
[0058]
The electron-emitting device manufactured as described above was placed in a vacuum chamber, and a voltage with the control electrode side being positive was applied between the lower electrode (electron supply layer) and the control electrode, and the amount of emission current was measured. . As a result, a radiation current density almost the same as that of the first embodiment was obtained.
[0059]
Further, (La, Sr) O.2 [(La, Sr) TiO _3-x ] Or (La, Sr) O.3 [(La, Sr) TiO _3-x ], A layered perovskite material represented by (La, Sr) ₂ TiO ₄ The same emission current density as in the case of was obtained. (La, Sr) O.2 [(La, Sr) TiO _3-x ] Or (La, Sr) O.3 [(La, Sr) TiO _3-x ] Is K ₂ NiF ₄ It has a structure similar to the structure shown in FIG. 6B, and is represented by (R, A) Zn [(R, A) MZ _3-x ] Has a crystal structure represented by When the ab plane is arranged to be dominant as the electron emission surface, the ABZ in FIG. ₃ (Sr, Ba, Ca), which is an alkaline earth metal element, can be efficiently arranged on the surface.
[0060]
In this embodiment, the ab plane is configured to be dominant as the electron emission surface. However, when the electron emission plane is arranged on the ac plane (bc plane), the obtained emission current density is deteriorated with respect to the ab plane. Was. This is considered to reflect the anisotropy of the crystal structure, that is, is evidence that the crystallized material has been realized on the surface.
[0061]
Further, by the same manufacturing method, NaxWO is added to the electron emitting layer. ₃ Was used to complete the electron-emitting device. NaxWO prepared at 0.15 ≦ x <1 ₃ Has a bronze type structure and a slightly distorted structure as compared with the perovskite type, but a high radiation current density similar to that of the first embodiment was obtained. In addition, D1xWO ₃ And D1MoO ₃ When K, Rb and Cs were used as D1 in the above, the same emission current density was obtained.
[0062]
(Fourth embodiment)
FIG. 2 is a schematic cross-sectional view of an electron-emitting device having a different form from the first to third embodiments. The basic structure of the electron emitting element is the first electron emitting element shown in FIG. 11 , The control electrode layer is directly laminated on the surface of the electron emitting layer. The method for producing the base material, the electron supply layer, and the electron emission layer of the present element is the same as in the first to third embodiments, and is therefore omitted, and the control electrode layer used in the present embodiment will be described below.
[0063]
The control electrode layer in the present embodiment is radiated through the electron supply layer / electron emission layer, and it is necessary to radiate electrons guided to the radiation surface into a vacuum by a tunnel effect. It is about 10 nm. The material is not particularly limited, but generally, a material having a small work function is good, and a material which is easy to manufacture is preferable. From these viewpoints, in this embodiment, the gold thin film is deposited by the resistance heating method.
[0064]
Further, in this embodiment, the gold thin film is deposited on the entire surface, but a part of the gold thin film may be removed with a fine hole-shaped pattern in order to increase the electron transmission efficiency.
[0065]
The obtained electron-emitting device was placed in a vacuum chamber, and a voltage was applied between the lower electrode (electron supply layer) and the control electrode with the control electrode side being positive, and the amount of emission current was measured. As a result, several tens mA / cm, which is several times higher than the conventional one, ² Was obtained.
[0066]
(Fifth embodiment)
Although the electron-emitting devices have been described in the first to fourth embodiments, a phosphor light-emitting device capable of controlling the amount of phosphor light-emission is manufactured by disposing an anode portion having a phosphor layer opposed thereto. be able to.
[0067]
FIG. 3 is a schematic sectional view of the phosphor light emitting device of the present embodiment. The present phosphor light-emitting device comprises, as basic components, the electron-emitting device portion described in the first embodiment, an anode portion, and a vacuum vessel containing them.
[0068]
In the present phosphor light emitting element, the configuration of the electron emitting element section is not limited to this, and the electron emitting element described in the embodiment shown in FIG. 2 may be used.
[0069]
Further, in the element structure shown in the figure, the electron emitting element part and the anode part are completely contained in the vacuum vessel. In addition, the anode part may be formed directly on the bottom part of the vacuum vessel, The electron emitting element portion and the anode portion may be bonded via a spacer without using a container, and the gap may be evacuated.
[0070]
The anode part is a region having a function of applying a voltage for accelerating the electrons emitted from the electron emitting element and causing the phosphor to emit light. The constituent elements include an accelerating voltage for the phosphor layer / emitted electrons. And a front substrate. In such a configuration, that is, when light is extracted from the front substrate, a transparent conductive film such as ITO is generally used as the anode electrode, and glass or the like is used as the front substrate.
[0071]
As the phosphor material used for the phosphor layer, ZnO: Zn or ZnS-based phosphor may be selected according to a desired emission color. However, it is important to select the most efficient phosphor material in consideration of the energy value of the accelerated emitted electrons, that is, the anode voltage value.
[0072]
In this embodiment, the anode portion is formed by laminating a transparent conductive film (ITO) functioning as an anode electrode on a front substrate made of glass and further applying a ZnS-based phosphor as a phosphor layer.
[0073]
The phosphor light emitting device manufactured as described above is placed in a vacuum chamber, and a voltage is applied between the lower electrode and the control electrode, with the control electrode side being positive, and electrons are emitted from the electron emitting element to the vacuum region. At the same time, an acceleration voltage of 3 kV was applied to the anode electrode, and the emission current and the emission luminance of the phosphor were measured. As a result, the emission current density was several tens mA / cm. ² Is observed, and 300 to 400 cd / m ² Was obtained.
[0074]
(Sixth embodiment)
In the first to fourth embodiments, a single electron-emitting device has been described. However, a plurality of these devices are two-dimensionally arranged, and an image drawing that can display an image or a character by controlling the light emission amount of each phosphor is performed. Applicable to equipment.
[0075]
FIG. 4 is a cross-sectional perspective view of an image drawing apparatus in which a plurality of electron emitting elements shown in FIGS. 1 and 2 are arranged two-dimensionally (3 rows × 3 columns = 9 in this figure). A method of drawing an image using this configuration is a method usually called matrix driving. That is, the lower electrode serving as the electron supply layer 2 formed in a strip shape on the base material 1 and the upper electrode serving as the control electrode layer 6 for controlling the amount of emission current in a strip shape are arranged orthogonally. Are connected to driving drivers 18 and 19. If image data is input to the respective drive drivers in conjunction with the synchronization signal, it becomes possible to emit electrons with a desired amount of electron emission from a desired electron emission surface (where each electrode row is orthogonal). .
[0076]
Therefore, in each electron emitting element, if the emitted electrons are accelerated in a vacuum by the voltage applied to the anode electrode 14 and are irradiated on the phosphor layer 13, an image having an arbitrary shape and an arbitrary brightness can be drawn.
[0077]
(Seventh embodiment)
First, SrTiO doped with 0.01 wt% of Nb ₃ A metal lower electrode was formed as an electron supply layer on one surface of a substrate made of. Although the lower electrode material is not particularly limited as described above, a platinum film having a thickness of 2 μm is used in this embodiment. The film was formed by heating at 400 ° C. The materials used for the electron-emitting layer were produced in the following manner, and the cooling elements shown in FIGS. 10 and 11 were produced.
[0078]
Rb _y WO ₃ An electron emission layer was formed by laser ablation using (0.15 ≦ y <1) as a target. As a laser light source, a KrF excimer laser is used. In the film formation, an ablation energy density is 0.1-10 J / cm. ² The heating was performed at a temperature of 400 to 700 ° C. in an oxygen atmosphere of 0.1 to 500 mTorr. The thickness of the manufactured electron emission layer was about 300 nm. In this case, the laser beam ablation method was used, but ion beam deposition (IBD), cluster ion beam or sputtering method such as RF, DC, ECR, helicon, ICP or opposed target, MBE, ion pre- It can be produced by a PVD method such as a plating method, other CVD, a plating method or a sol-gel method, and is not limited.
[0079]
FIGS. 10 and 11 are schematic cross-sectional views of the cooling element according to the present embodiment. The element includes, as basic components, a base material, an electron supply layer, an electron emission layer, an anode electrode body, and a base material. A heat bath, which is a heat source in contact with the above, and a vacuum vessel containing them.
[0080]
In the present cooling element, the configuration for realizing electron emission is not limited to this, and a cooling element having the configuration shown in FIG. 12 may be realized.
[0081]
The cooling element fabricated as described above is placed in a vacuum chamber, and a voltage is applied between the lower electrode and the control electrode, with the control electrode side being positive, as shown in FIG. At the same time, an acceleration voltage of 3 kV was applied to the anode electrode, and the emission current and cooling characteristics were measured. As a result, a radiation current density of several tens mA / cm between the electron emission side and the anode electrode body side. ² Was observed, and a temperature difference of several tens of degrees Celsius was obtained.
[0082]
Further, in the element structure shown here, the electron emitting layer and the anode electrode body are completely contained in the vacuum vessel, but in addition, the anode electrode body may be formed directly on the bottom surface of the vacuum vessel. Alternatively, the substrate and the electron supply layer may be formed on the bottom of the vacuum container. Alternatively, the electron emitting layer and the anode electrode body may be bonded together via a spacer without using a vacuum vessel, and the gap may be evacuated. Further, a radiator such as a fin may be provided on the anode electrode body as shown in FIG. 13 in order to improve the heat radiation efficiency. Further, it is also preferable to blow the wind from the fan to the radiator.
[0083]
For electron conduction at this time, the distance between the electron emitting layer and the anode electrode body is preferably 50 nm or less. In particular, for heat transport by electron conduction through a vacuum, 15 nm or less is preferable because of high heat transport efficiency.
[0084]
It is considered that such good characteristics as obtained in the present embodiment are due to the efficient arrangement of Rb, which is an alkaline earth metal element, on the surface. In addition, it is assumed that oxygen deficiency may partially occur in the oxide crystal. _y WO ₃ In the range of 0.15 ≦ y <1, similarly good characteristics can be obtained.
[0085]
Further, (La, Sr) O.2 [(La, Sr) TiO _3-x ] Or (La, Sr) O.3 [(La, Sr) TiO _3-x ], A layered perovskite material represented by (La, Sr) ₂ TiO ₄ The same radiation current density and cooling characteristics as in the case of were obtained.
[0086]
In this embodiment, the ab plane is configured to be dominant as the electron emission surface. However, when the electron emission plane is arranged on the ac plane (bc plane), the obtained emission current density is deteriorated with respect to the ab plane. Was. This is considered to reflect the anisotropy of the crystal structure, that is, is evidence that the crystallized material has been realized on the surface.
[0087]
Further, by the same manufacturing method, NaxWO is added to the electron emitting layer. ₃ Was used to complete the electron-emitting device. NaxWO prepared at 0.15 ≦ x <1 ₃ Has a bronze type structure and a slightly distorted structure as compared with the perovskite type, but high radiation current density and cooling characteristics similar to those of the first embodiment were obtained. In addition, D1xWO ₃ And D1MoO ₃ When K, Rb, and Cs were used as D1 in the above, similar radiation current densities and cooling characteristics were obtained.
[0088]
Further, the materials of the electron-emitting layers shown in Tables 1 and 2 which obtained high current densities in the electron-emitting devices shown in Examples 1 and 2 were used as the electron-emitting layers of the cooling element in this example. In each case, a high radiation current density and high cooling characteristics were obtained when any of the materials was used.
[0089]
(Eighth embodiment)
Using the same material configuration shown in the seventh embodiment, the power generation element in FIG. 14 was manufactured.
[0090]
First, SrTiO doped with 0.01 wt% of Nb ₃ A metal lower electrode was formed as an electron supply layer on one surface of a substrate made of. Although the lower electrode material is not particularly limited as described above, a platinum film having a thickness of 2 μm is used in this embodiment. The film was formed by heating at 400 ° C. The material used for the electron emitting layer was produced in the following manner.
[0091]
Rb _y WO ₃ An electron emission layer was formed by laser ablation using (0.15 ≦ y <1) as a target. The fabrication is the same as that of the seventh embodiment, and is omitted here.
[0092]
FIG. 14 is a schematic cross-sectional view of the cooling element of the present embodiment, and the element was in contact with a base, an electron supply layer, an electron emission layer, an anode electrode body, and a base as basic components. It comprises a heat bath 1, a heat bath 2 in contact with the anode electrode body, and a vacuum container containing them.
[0093]
In the present power generation element, the configuration for realizing electron emission is not limited to this, and a power generation element having a configuration similar to the cooling element having the configuration shown in FIGS. 10 to 12 may be realized.
[0094]
The cooling element fabricated as described above is placed in a vacuum chamber, and a voltage is applied between the lower electrode and the control electrode, with the control electrode side being positive, as shown in FIG. And a temperature difference of about 50 ° C. was realized under the condition of temperature (heat bath 1)> temperature (heat bath 2), and the emission current between the electron emission side and the anode electrode side was measured. As a result, the emission current density was several tens mA / cm. ² Was observed, and the operation of the power generating element was confirmed.
[0095]
Also, in the element structure shown here, the electron emitting layer and the anode electrode body are completely contained in the vacuum vessel, but in addition, the anode electrode body may be formed directly on the bottom surface of the vacuum vessel. Alternatively, the substrate and the electron supply layer may be formed on the bottom of the vacuum container.
[0096]
It is considered that such good characteristics as obtained in the present embodiment are due to the efficient arrangement of Rb, which is an alkaline earth metal element, on the surface. In addition, it is assumed that oxygen deficiency may partially occur in the oxide crystal. _y WO ₃ In the range of 0.15 ≦ y <1, similarly good characteristics can be obtained.
[0097]
Further, (La, Sr) O.2 [(La, Sr) TiO _3-x ] Or (La, Sr) O.3 [(La, Sr) TiO _3-x ], A layered perovskite material represented by (La, Sr) ₂ TiO ₄ The same radiation current density and cooling characteristics as in the case of were obtained.
[0098]
In this embodiment, the ab plane is configured to be dominant as the electron emission surface. However, when the electron emission plane is arranged on the ac plane (bc plane), the obtained emission current density is deteriorated with respect to the ab plane. Was. This is considered to reflect the anisotropy of the crystal structure, that is, is evidence that the crystallized material has been realized on the surface.
[0099]
Further, by the same manufacturing method, NaxWO is added to the electron emitting layer. ₃ Was used to complete the electron-emitting device. NaxWO prepared at 0.15 ≦ x <1 ₃ Has a bronze type structure and a slightly distorted structure as compared with the perovskite type, but high radiation current density and cooling characteristics similar to those of the first embodiment were obtained. In addition, D1xWO ₃ And D1MoO ₃ When K, Rb, and Cs were used as D1 in the above, similar radiation current densities and cooling characteristics were obtained.
[0100]
Further, the materials of the electron-emitting layers shown in Tables 1 and 2 which obtained high current densities in the electron-emitting devices shown in Examples 1 and 2 were used as the electron-emitting layers of the cooling element in this example. In each case, a high radiation current density and high cooling characteristics were obtained when any of the materials was used.
[0101]
(Ninth embodiment)
In the present embodiment, a cooling panel in which a plurality of cooling element structures shown in the eighth embodiment are two-dimensionally arranged is manufactured.
[0102]
FIG. 15 is a cross-sectional perspective view of a cooling element in which a plurality of cooling elements shown in FIGS. 10, 11, 12, and the like are two-dimensionally arranged. Normally, using a method called matrix driving, the lower electrode serving as an electron supply layer formed in a strip shape on the base material and the upper electrode serving as a control electrode layer for controlling the amount of radiated current in the same manner cross at right angles. By arranging and realizing a structure in which drive drivers are connected to each other, it is possible to adjust the degree of cooling at a desired position by inputting data to each drive driver along with a synchronization signal It becomes. In addition, the temperature distribution of the heat bath is fed back as data, so that the cooling panel as a whole can be made uniform. If a cooling element is realized using this configuration, a large-sized cooling panel can be easily realized.
[0103]
Therefore, in each cooling element, a cooling panel having an arbitrary shape and an arbitrary temperature can be realized by accelerating the emitted electrons in a vacuum by the voltage applied to the anode electrode.
(Tenth embodiment)
In the first to ninth embodiments, a vacuum is used as a region where electron emission is performed. However, when a vacuum is provided as an insulator layer, the distance between the electron emission layer and the anode unit is reduced in a vacuum environment. Can be adjusted to bring them closer. The distance can be controlled using a piezoelectric body or the like.
[0104]
In another embodiment, it is preferable to use an amorphous body or a microcrystalline body as an insulator other than a vacuum. Here, the term “microcrystalline material” refers to a material having a crystal diameter of 10 nm or less and dispersed in an amorphous material. Alternatively, it is preferable to use an inorganic polymer material as the insulator. Among inorganic polymer materials, a porous inorganic polymer having a silicate or aluminum silicate material as a base is preferable.
[0105]
The porous body referred to here is a solid substance having continuous pores or independent pores, and a method such as molding of a base material powder, powder firing, chemical foaming, physical foaming, and a sol-gel method. Can be produced. In the electron emitting element of the present invention, it is possible to obtain an advantageous effect that the porous body has a large number of nanometer-sized holes.
[0106]
FIG. 16 is a schematic diagram simulating a fine structure used as an insulator, and is made of a porous base material constituting a skeleton. The porous structure is a solid skeleton composed of particles with a size of about several nanometers in a three-dimensional network. It is in the state including. In some cases, a particulate electron-emitting material having a size equal to or smaller than that of the vacancy is further dispersed. In other words, the electric field is concentrated on the solid skeleton forming the porous structure of the insulator by the voltage applied between the electrode bodies, so that the electrons are more efficiently sent into the insulator than the electron emitter, and the electrons are directed to the anode electrode body. Radiated. The electric field concentration effect related to the supply of electrons becomes remarkable when the base material of the insulator is made to have a porous structure, and electrons can be efficiently transmitted between the electron emitting layer and the anode electrode body.
[0107]
In the above principle, naturally, some of the supplied electrons are scattered by the solid phase component of the porous body and some lose energy, but since the size of the solid phase region is about several nm, Most of the electrons can be used as heat transfer components.
[0108]
Similarly, some of the electrons emitted from the electron emitting layer are again scattered by the solid phase component of the porous body, but can be emitted again by being transmitted to the electron emitting material again.
[0109]
As such a porous structure having a structure containing a large amount of a gas phase, a dry gel produced by a sol-gel method can be particularly used as a candidate. Here, the dry gel is a nanoporous body having a solid skeleton portion composed of particles having a size of several to several tens of nm and having continuous pores having an average pore diameter of 100 nm or less. is there. In addition, as the material thereof, a semiconductor material and an insulator material exhibiting relatively high resistance and having high electric field concentration effect are suitable, and porous silica (porous silicon oxide) is particularly preferable. Therefore, a method for manufacturing a porous first insulator will be described using porous silica as a preferred example as an example.
[0110]
The method for obtaining porous silica composed of a dried gel used in the present invention comprises a step of obtaining a large wet gel and a step of drying it.
[0111]
First, a wet gel can be synthesized by subjecting a raw material of silica mixed in a solvent to a sol-gel reaction. At this time, a catalyst is used if necessary. In this formation process, the raw materials react in a solvent to form fine particles, and the fine particles are networked to form a network skeleton. Specifically, the composition of the raw material and the solvent, which are solid components, is determined so that porous silica having a predetermined porosity is obtained. If necessary, a catalyst, a viscosity modifier and the like are added to the solution prepared according to the composition, and the mixture is stirred, and a desired use form is formed by coating or the like. The application method is not limited since it varies depending on the film thickness and the shape thereof, but a spin coating method, a dipping method, a screen printing method, or the like can be used.
[0112]
When a certain period of time elapses in this state, the solution gels, and a silica wet gel is obtained. As a temperature condition at the time of production, it can be carried out near a normal working temperature of room temperature, but if necessary, it may be heated to a temperature lower than the boiling point of the solvent.
[0113]
Raw materials for silica include alkoxysilane compounds such as tetramethoxysilane, tetraethoxysilane, trimethoxymethylsilane, and dimethoxydimethylsilane; oligomeric compounds thereof; and water glass such as sodium silicate (sodium silicate) and potassium silicate. Compounds and the like, and colloidal silica and the like can be used alone or as a mixture.
[0114]
The solvent may be any solvent as long as the raw material can be dissolved to form silica, and water or a common organic solvent such as methanol, ethanol, propanol, acetone, toluene, and hexane can be used alone or as a mixture.
[0115]
As the catalyst, water, an acid such as hydrochloric acid, sulfuric acid, and acetic acid, and a base such as ammonia, pyridine, sodium hydroxide, and potassium hydroxide can be used.
[0116]
As the viscosity adjusting agent, ethylene glycol, glycerin, polyvinyl alcohol, silicone oil, or the like can be used, but is not limited thereto as long as the wet gel can be used in a predetermined form.
[0117]
In the above description, the method of forming only the porous body serving as the base material has been described. However, as a method of dispersing the particulate electron emitting material simultaneously with the formation of the porous body, the electron emitting material particles may be appropriately dispersed in a sol-gel reaction solvent. Can be prepared by mixing and gelling.
[0118]
Next, a drying step for obtaining a dry gel from a wet gel will be described.
[0119]
In the drying step, an ordinary drying method such as natural drying, heat drying, and drying under reduced pressure, a supercritical drying method, and a freeze drying method can be used. However, in general, in the ordinary drying method, the porous body shrinks due to stress at the time of solvent evaporation. Therefore, as a method for forming a dried gel, supercritical drying can be preferably used in the present invention. In addition, the surface of the solid component of the wet gel can be subjected to a water-repellent treatment or the like to prevent gel shrinkage during drying.
[0120]
The solvent used for the supercritical drying may be a wet gel solvent. If necessary, it is preferable to substitute a solvent that can be easily handled in supercritical drying. Examples of the solvent to be replaced include alcohols such as methanol, ethanol, and isopropyl alcohol used as a supercritical fluid, carbon dioxide, and water. Further, it may be replaced with an organic solvent which is generally easy to handle, such as acetone, isoamyl acetate, and hexane, which are easily eluted in these supercritical fluids.
[0121]
Supercritical drying conditions are carried out in a pressure vessel such as an autoclave. For example, methanol is set to a critical pressure of 8.09 MPa and a temperature of 239.4 ° C. or higher, and the pressure is gradually released at a constant temperature for drying. Perform In the case of carbon dioxide, drying is performed by setting the critical pressure to 7.38 MPa and the critical temperature to 31.1 ° C. or higher, and gradually releasing the pressure from the supercritical state in the same constant temperature state. In the case of water, drying is performed at a critical pressure of 22.04 MPa and a critical temperature of 374.2 ° C. or higher. The time required for drying may be longer than the time required for the solvent in the wet gel to be replaced one or more times by the supercritical fluid.
[0122]
In the method of drying the wet gel after performing the water-repellent treatment, a surface treatment agent for the water-repellent treatment is chemically reacted with the surface of the solid component of the wet gel. Thereby, the surface tension generated in the pores of the network structure of the wet gel can be reduced, and the shrinkage that normally occurs during drying can be suppressed.
[0123]
Examples of surface treatment agents include halogen-based silane treatment agents such as trimethylchlorosilane and dimethyldichlorosilane, alkoxy-based silane treatment agents such as trimethylmethoxysilane and trimethylethoxysilane, and silicone-based silane treatment agents such as hexamethyldisiloxane and dimethylsiloxane oligomer. Treatment agents, amine-based silane treatment agents such as hexamethyldisilazane, and alcohol-based treatment agents such as propyl alcohol and butyl alcohol can be used. However, as long as similar effects can be obtained, these surface treatment agents are limited. It is not something that can be done.
[0124]
In addition, as a material of the dried gel obtained by this method, not only silica but also other inorganic materials and organic polymer materials can be used. As the solid skeleton portion of the dried gel of the inorganic oxide, a general ceramic obtained by a sol-gel reaction such as silica (silicon oxide) or aluminum oxide (alumina) can be used as a component.
[0125]
The method of forming the porous inorganic polymer material constituting the insulator as a substitute for the vacuum section has been described above. The above-described porous inorganic polymer was applied to the phosphor light emitting device of FIG. 3 and evaluated. As a result, the same high emission current density and light emission characteristics as in the fifth embodiment were obtained.
[0126]
Further, the above-described porous inorganic polymer was applied to the cooling element shown in FIG. 11, and evaluation was performed. As a result, the same high radiation current density and cooling result as those of the seventh embodiment were obtained.
[0127]
【The invention's effect】
According to the present invention, a substrate, a conductive or semiconductive electron supply layer that supplies electrons, an electron emission layer that emits electrons, and a control electrode layer that controls the amount of emitted electrons by applying a voltage are provided. By using an oxide crystal material containing an alkali metal or an alkaline earth metal as the electron emitting layer in the electron emitting element configured with this, a stable surface with a low work function is realized, and highly efficient electron emission is realized. it can.
[0128]
The electron emitting element of the present invention and an anode section provided with a phosphor layer as constituent elements, a plurality of electron emitting elements are arranged two-dimensionally, and individual phosphors are determined by the amount of electron emission from the electron emitting element. An image drawing apparatus can be realized by individually controlling the light emission amount.
[0129]
It further includes a base material, a conductive or semiconductive electron supply layer for supplying electrons, an electron emission layer for emitting electrons, and a control electrode layer for controlling the amount of emitted electrons by applying a voltage. A high-efficiency cooling element for material cooling is realized. In addition, by providing a temperature difference between the base material or the electron supply layer and the control electrode layer, a high-efficiency power generation element that allows a current to flow between both layers can be realized.
[Brief description of the drawings]
FIG. 1 is a cross-sectional configuration diagram of an electron-emitting device according to an embodiment.
FIG. 2 is a schematic cross-sectional view of an electron-emitting device having a different form from the first to third embodiments.
FIG. 3 is a schematic cross-sectional view of a phosphor light emitting device of the present embodiment.
FIG. 4 is a sectional perspective view of an image drawing apparatus in which a plurality of electron emitting elements are two-dimensionally arranged.
FIG. 5: Perovskite-type crystal structure ABZ ₃ Figure showing
FIG. 6 shows a perovskite-type related crystal structure K2NiF4 and (R, A) Zn [(R, A) MZ _3-x Figure showing
FIG. 7 is a sectional structural view of an example of a conventional Spindt-type FE electron-emitting device.
FIG. 8 is a cross-sectional structural view of an example of a conventional MIM / BSD type FE electron emitting element.
FIG. 9 is a diagram showing a cooling element shown in Non-Patent Document 1.
FIG. 10 shows a cooling element according to the present invention.
FIG. 11 shows a cooling element according to the present invention.
FIG. 12 shows a cooling element according to the present invention.
FIG. 13 is a diagram showing a cooling element according to the present invention in which a radiator such as a fin is disposed on an anode electrode body.
FIG. 14 is a diagram showing a power generating element according to the present invention.
FIG. 15 is a cross-sectional perspective view of a cooling element in which a plurality of cooling elements according to the present invention are two-dimensionally arranged.
FIG. 16 is a schematic diagram illustrating a fine structure used as an insulator.
[Explanation of symbols]
1: Substrate
2: Electron supply layer
6: Control electrode layer
13: Phosphor layer
14: Anode electrode
18: Driver for driving
19: Driver for driving

Claims (20)

A base material, a conductive or semiconductive electron supply layer provided on the base material to supply electrons, and electron emission provided on the electron supply layer and emitting electrons supplied from the electron supply layer A layer and a control electrode layer arranged through the electron emitting layer and the space and controlling the amount of emitted electrons by applying a voltage, wherein an alkali metal or an alkaline earth metal is used as the electron emitting layer. An electron-emitting device characterized by using a crystallization material containing the same. The electron-emitting device according to claim 1, wherein a material represented by a chemical formula AMZ _3-x is used as a crystallization material as a base material.
Here, A is at least one of Ca, Sr, Ba, Li, Na, K, and Rb, and M is Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Zr, Nb, Mo, Ru, Ta, and Ir are included at least. Z includes at least one of O, N, and F, and x indicates a range of 0 ≦ x ≦ 1. The electron-emitting device according to claim 1, wherein a material represented by a chemical formula (R, A) MZ _3-x is used as a crystallization material as a base material.
However, R includes Y and excludes Pm, except for at least one of the elements of element numbers 57 to 70, A includes at least one of Ca, Sr, and Ba, and M includes Ti, V, Cr, Mn, At least one of Fe, Co, Ni, Cu, Zn, Ga, Zr, Nb, Mo, Ru, and Ta is included. Z includes at least one of O, N, and F, and x indicates a range of 0 ≦ x ≦ 1. The material crystallized material is represented by the formula _{(R, A) 2 MZ 4} -x which comprises using as the base material, an electron emission device according to claim 1.
However, R includes Y and excludes Pm, except for at least one of the elements of element numbers 57 to 70, A includes at least one of Ca, Sr, and Ba, and M includes Ti, V, Cr, Mn, At least one of Fe, Co, Ni, Cu, Zn, Ga, Zr, Nb, Mo, Ru, and Ta is included. Z includes at least one of O, N, and F, and x indicates a range of 0 ≦ x ≦ 1. 2. The electron-emitting device according to claim 1, wherein the crystallization material uses a material represented by a chemical formula (R, A) Z · n [(R, A) MZ _3-x ] as a base material. 3.
However, R includes Y and excludes Pm, except for at least one of the elements of element numbers 57 to 70, A includes at least one of Ca, Sr, and Ba, and M includes Ti, V, Cr, Mn, At least one of Fe, Co, Ni, Cu, Zn, Ga, Zr, Nb, Mo, Ru, and Ta is included. n represents a positive integer of 1 or more. Z includes at least one of O, N, and F, and x indicates a range of 0 ≦ x ≦ 1. The material crystallized material is represented by Formula D1 y _{MbO 3-x} characterized by using as a base material, an electron emission device according to claim 1.
Here, D1 includes at least one of Li, Na, K, Rb, Cs, Mg, Ca, Sr, and Ba, and Mb includes at least one of W and Mo.
Y indicates a range of 0.15 ≦ y <1. X indicates a range of 0 ≦ x ≦ 1. 7. An electron-emitting device according to claim 1, wherein an anode portion provided with a phosphor layer is provided as a component, and a phosphor is emitted by electrons emitted from the electron-emitting device. Phosphor light emitting device. The electron-emitting device according to any one of claims 1 to 6, and an anode unit having a phosphor layer as a component, and a plurality of the electron-emitting devices are two-dimensionally arranged. An image drawing apparatus characterized in that each phosphor emission amount is individually controlled by the amount of electron emission. A base material, a conductive or semiconductive electron supply layer provided on the base material to supply electrons, and electron emission provided on the electron supply layer and emitting electrons supplied from the electron supply layer A cooling element for cooling the base material by applying a voltage, comprising: a layer; a control electrode layer arranged through the space with the electron-emitting layer to control the amount of emitted electrons by applying a voltage; A cooling element using an oxide crystal material containing an alkali metal or an alkaline earth metal. The cooling element according to claim 9, wherein a material represented by a chemical formula AMZ _3-x is used as a base material as the oxide crystal material.
Here, A is at least one of Ca, Sr, Ba, Li, Na, K, and Rb, and M is Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Zr, Nb, Mo, Ru, Ta, and Ir are included at least. Z includes at least one of O, N, and F, and x indicates a range of 0 ≦ x ≦ 1. The cooling element according to claim 9, wherein a material represented by a chemical formula (R, A) MZ _3-x is used as a base material as the oxide crystal material.
However, R includes Y and excludes Pm, except for at least one of the elements of element numbers 57 to 70, A includes at least one of Ca, Sr, and Ba, and M includes Ti, V, Cr, Mn, At least one of Fe, Co, Ni, Cu, Zn, Ga, Zr, Nb, Mo, Ru, and Ta is included. Z includes at least one of O, N, and F, and x indicates a range of 0 ≦ x ≦ 1. A material oxide crystal material is represented by the formula _{(R, A) 2 MZ 4} -x which comprises using as the base material, the cooling device according to claim 9.
However, R includes Y and excludes Pm, except for at least one of the elements of element numbers 57 to 70, A includes at least one of Ca, Sr, and Ba, and M includes Ti, V, Cr, Mn, At least one of Fe, Co, Ni, Cu, Zn, Ga, Zr, Nb, Mo, Ru, and Ta is included. Z includes at least one of O, N, and F, and x indicates a range of 0 ≦ x ≦ 1. The cooling element according to claim 9, wherein the oxide crystal material uses a material represented by a chemical formula (R, A) Zn ((R, A) MZ3 _-x ) as a base material.
However, R includes Y and excludes Pm, except for at least one of the elements of element numbers 57 to 70, A includes at least one of Ca, Sr, and Ba, and M includes Ti, V, Cr, Mn, At least one of Fe, Co, Ni, Cu, Zn, Ga, Zr, Nb, Mo, Ru, and Ta is included. n represents a positive integer of 1 or more. Z includes at least one of O, N, and F, and x indicates a range of 0 ≦ x ≦ 1. A material oxide crystal material is represented by Formula D1 y _{MbO 3-x} characterized by using as the base material, the cooling device according to claim 9.
Here, D1 includes at least one of Li, Na, K, Rb, Cs, Mg, Ca, Sr, and Ba, and Mb includes at least one of W and Mo.
Y indicates a range of 0.15 ≦ y <1. X indicates a range of 0 ≦ x ≦ 1. A base material, a conductive or semiconductive electron supply layer provided on the base material to supply electrons, and electron emission provided on the electron supply layer and emitting electrons supplied from the electron supply layer A control electrode layer disposed between the electron emission layer and the space and controlling the amount of emitted electrons by applying a voltage, and providing a temperature difference between the base material or the electron supply layer and the control electrode layer. A power generating element for generating a voltage between both layers, wherein the electron emitting layer uses an oxide crystal material containing an alkali metal or an alkaline earth metal. The power generating element according to claim 15, wherein a material represented by a chemical formula AMZ3 _-x is used as a base material as the oxide crystal material.
Here, A is at least one of Ca, Sr, Ba, Li, Na, K, and Rb, and M is Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Zr, Nb, Mo, Ru, Ta, and Ir are included at least. Z includes at least one of O, N, and F, and x indicates a range of 0 ≦ x ≦ 1. The power generating element according to claim 15, wherein a material represented by a chemical formula (R, A) MZ _3-x is used as a base material as the oxide crystal material.
However, R includes Y and excludes Pm, except for at least one of the elements of element numbers 57 to 70, A includes at least one of Ca, Sr, and Ba, and M includes Ti, V, Cr, Mn, At least one of Fe, Co, Ni, Cu, Zn, Ga, Zr, Nb, Mo, Ru, and Ta is included. Z includes at least one of O, N, and F, and x indicates a range of 0 ≦ x ≦ 1. A material oxide crystal material is represented by the formula _{(R, A) 2 MZ 4} -x which comprises using as the base material, the power generation device according to claim 15.
However, R includes Y and excludes Pm, except for at least one of the elements of element numbers 57 to 70, A includes at least one of Ca, Sr, and Ba, and M includes Ti, V, Cr, Mn, At least one of Fe, Co, Ni, Cu, Zn, Ga, Zr, Nb, Mo, Ru, and Ta is included. Z includes at least one of O, N, and F, and x indicates a range of 0 ≦ x ≦ 1. The power generating element according to claim 15, wherein the oxide crystal material uses a material represented by a chemical formula (R, A) Zn ((R, A) MZ3 _-x ] as a base material.
However, R includes Y and excludes Pm, except for at least one of the elements of element numbers 57 to 70, A includes at least one of Ca, Sr, and Ba, and M includes Ti, V, Cr, Mn, At least one of Fe, Co, Ni, Cu, Zn, Ga, Zr, Nb, Mo, Ru, and Ta is included. n represents a positive integer of 1 or more. Z includes at least one of O, N, and F, and x indicates a range of 0 ≦ x ≦ 1. A material oxide crystal material is represented by Formula D1 y _{MbO 3-x} characterized by using as the base material, the power generation device according to claim 15.
Here, D1 includes at least one of Li, Na, K, Rb, Cs, Mg, Ca, Sr, and Ba, and Mb includes at least one of W and Mo.
Y indicates a range of 0.15 ≦ y <1. X indicates a range of 0 ≦ x ≦ 1.

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