JP4399518B2

JP4399518B2 - Phosphor for vacuum ultraviolet ray, method for producing the same, phosphor paste composition, and vacuum ultraviolet light emitting device

Info

Publication number: JP4399518B2
Application number: JP20146198A
Authority: JP
Inventors: 秀雄鈴木; 章裕大戸; 正和那部; 孝之久宗
Original assignee: Mitsubishi Chemical Corp
Current assignee: Mitsubishi Chemical Corp
Priority date: 1998-07-16
Filing date: 1998-07-16
Publication date: 2010-01-20
Anticipated expiration: 2018-07-16
Also published as: JP2000034478A

Description

【０００１】
【発明の属する技術分野】
本発明は、プラズマディスプレイパネル、希ガス放電ランプ等に使用される真空紫外線で励起されて発光する真空紫外線励起発光素子用蛍光体、その製造方法、その蛍光体を含有する蛍光体ペースト組成物及びその蛍光体ペースト組成物を用いて形成した蛍光膜を備えた真空紫外線励起発光素子に関する。
【０００２】
【従来の技術】
近年、Ａｒ、Ｘｅ、Ｈｅ、Ｎｅ、Ｘｅ−Ｎｅ等の希ガスをガラスなどの真空外囲器に封入し、その希ガスの放電によって放射される真空紫外線で、外囲器内部の蛍光膜を励起して発光させる真空紫外線励起発光素子の開発が盛んに行われている。
【０００３】
その一例がスキャナーの読みとり用光源等に使用される細管ランプである。その細管には、Ｘｅ、Ｘｅ−Ｎｅ等の希ガスが封入されていて、その管の内面には、真空紫外線で励起されて発光する蛍光体からなる蛍光膜が形成されている。そして、細管の両端に設けた電極から電気エネルギーを印加すると、細管内で希ガス放電が起こり、真空紫外線が放射される。この真空紫外線により蛍光体が励起されて可視光を発する。
【０００４】
塗布される蛍光体は、赤、青、緑に発光する単色の蛍光体と、単色に発光する３色の蛍光体を混合したものがある。赤色発光蛍光体は（Ｙ，Ｇｄ）ＢＯ₃：Ｅｕ、緑色発光蛍光体はＬａＰＯ₄：Ｃｅ，Ｔｂ、青色発光蛍光体はＢａＭｇＡｌ₁₀Ｏ₁₇：Ｅｕ、（Ｂａ，Ｓｒ）ＭｇＡｌ₁₀Ｏ₁₇：Ｅｕ，Ｍｎなどが使用される。
【０００５】
真空紫外線励起発光素子の他には、プラズマデイスプレイパネル（以下「ＰＤＰ」という）がある。ＰＤＰは原理的には、前記の真空紫外線励起の細管ランプを小さくし、異なる発光色の３色のランプをマトリックス状に並べたものと考えることができる。即ち、狭い放電空間（以下「セル」という）がマトリックス状に配置されたものである。各セルには電極が設けられ、各セルの内あるいは外に蛍光体が塗布されて蛍光膜が形成され、各セル内にはＸｅ，Ｘｅ−Ｎｅ等の希ガスが封入されている。電極から電気エネルギーを印加すると、セル内に希ガス放電が起こり、真空紫外線が放射される。この真空紫外線により蛍光体が励起されて可視光を発し、この発光によって画像が表示される。
【０００６】
フルカラーＰＤＰの場合、真空紫外線励起により赤、青、緑に発光する各蛍光体をマトリックス状に塗り分けることにより、フルカラーの表示を行うことができる。ここでは、赤色発光蛍光体として（Ｙ，Ｇｄ）ＢＯ₃：Ｅｕ、緑色発光蛍光体としてＺｎ₂ＳｉＯ₄：Ｍｎ、青色発光蛍光体としてＢａＭｇＡｌ₁₀Ｏ₁₇：Ｅｕ等が使用されている。（工業調査会発行、電子材料誌、１９９７年１２月号参照）
【０００７】
細管ランプもＰＤＰも蛍光体を塗布して蛍光膜を形成するときには蛍光体をバインダー樹脂に分散させた蛍光体ペーストが使用される。
細管ランプの場合、通常、蛍光体とニトロセルロースなどの樹脂を酢酸ブチルなどの溶媒を用いて混合し、蛍光体ペーストとしガラス管の内面に塗布し、乾燥した後、焼成することによりガラス管の内面に蛍光体塗布膜を形成する。
また、ＰＤＰの場合、蛍光体とエチルセルロースなどの樹脂とブチルカルビトールなどの溶媒を混合して、蛍光体ペーストとし、これをスクリーン印刷法によりＰＤＰの内面に塗布し、乾燥した後、焼成することによりＰＤＰセル内に蛍光体塗布膜を形成するのが一般的である。
【０００８】
このように真空紫外線励起発光素子の蛍光膜の形成においては、蛍光体ペースト組成物を塗布し、乾燥し、次いでこれを焼成することが必須である。この焼成工程において、蛍光体が劣化するという問題があった。特に、青色発光蛍光体のＢａＭｇＡｌ₁₀Ｏ₁₇：Ｅｕ、（Ｂａ，Ｓｒ）ＭｇＡｌ₁₀Ｏ₁₇：Ｅｕ，Ｍｎなど、Ｅｕを付活剤とするアルミン酸塩蛍光体の劣化が大きく、高輝度の青色発光蛍光体を用いて素子化しても、得られた真空紫外線励起発光素子の青色発光成分の発光輝度の低下を避けることができなかった。それ故、焼成工程における発光輝度の劣化の少ない蛍光体及び蛍光体ペーストの開発が望まれていた。
【０００９】
【発明が解決しようとする課題】
そこで、本発明は、上記の欠点を解消し、真空紫外線励起発光素子の蛍光膜の成膜工程における発光輝度の劣化が少ない、高輝度の真空紫外線励起発光素子用蛍光体、その製造方法、蛍光体ペースト組成物及びこれを用いた真空紫外線励起発光素子を提供しようとするものである。
【００１０】
【課題を解決するための手段】
本発明者等は、上記課題を解決するために、真空紫外線励起により発光する蛍光体の表面を種々の物質で被覆して輝度劣化の防止効果を鋭意検討した結果、蛍光体の表面に特定組成を有する２価金属の珪酸塩を被覆することにより、上記の焼成工程における輝度劣化を抑制できることを見出し、高輝度発光の真空紫外線励起発光素子用蛍光体及び真空紫外線励起発光素子を完成した。即ち、本発明の構成は次のとおりである。
【００１１】
(1) 一般式（Ｍ ^１ _１−ｘＥｕ _ｘ）Ｏ・ａ（Ｍ ^２ _１−ｙ，Ｍｎ _ｙ）Ｏ・（５．５−０．５ａ）Ａｌ _２Ｏ _３で表されるアルミン酸塩蛍光体（ただし、前記一般式中、Ｍ ^１はＢａ、Ｓｒ及びＣａからなる群より選択される少なくとも１種の元素を表し、Ｍ ^２はＭｇ及び／又はＺｎを表し、ａは、０＜ａ≦２の実数を表し、ｘ及びｙはそれぞれ０＜ｘ＜１、０≦ｙ＜１の実数を表す）が、該アルミン酸塩蛍光体重量に対して０．０１〜１５ｗｔ％の一般式Ｍ_ｍＳｉ_ｎＯ_ｍ＋２ｎで表される珪酸塩（ただし、Ｍは、Ｍｇ、Ｃａ、Ｓｒ、Ｂａ及びＺｎの群から選択される少なくとも１種の金属元素であり、ｍ及びｎは０．１≦（ｍ／ｎ）≦１０を満たす数である）で被覆されていることを特徴とする真空紫外線励起発光素子用蛍光体。
【００１２】
(2) 前記ｙ値がｙ＝０であることを特徴とする前記(1) に記載の真空紫外線励起発光素子用蛍光体。
【００１３】
(3) 前記アルミン酸塩蛍光体を溶媒に分散させてなる蛍光体スラリー中に、前記溶媒に溶解する、Ｍｇ、Ｃａ、Ｓｒ、Ｂａ及びＺｎの群から選択された少なくとも一種の金属の化合物と、溶液中で珪酸イオンを遊離する珪素化合物とを化学量論的に一般式Ｍ_ｍＳｉ_ｎＯ_ｍ _＋２ｎで表される珪酸塩（ただし、Ｍは、Ｍｇ、Ｃａ、Ｓｒ、Ｂａ及びＺｎの群から選択される少なくとも１種の金属元素であり、ｍ及びｎは０．１≦（ｍ／ｎ）≦１０を満たす数である）となる割合で加えて混合することにより前記金属の珪酸塩を生成させ、前記アルミン酸塩蛍光体表面に前記金属の珪酸塩を付着させることを特徴とする前記 (1)又は(2)に記載の真空紫外線励起発光素子用蛍光体の製造方法。
【００１４】
(4) 蛍光体をバインダー樹脂中に分散させてなる蛍光体ペースト組成物において、前記蛍光体が前記(1)又は(2)に記載の真空紫外線励起発光素子用蛍光体からなることを特徴とする蛍光体ペースト組成物。
【００１５】
(5) 真空外囲器内に蛍光膜を形成し、希ガスを封入してなる真空紫外線励起発光素子において、前記蛍光膜が前記(1)又は(2)に記載の真空紫外線励起発光素子用蛍光体からなることを特徴とする真空紫外線励起発光素子。
【００１６】
【発明の実施の形態】
本発明の真空紫外線励起発光素子用蛍光体（以下、真空紫外線用蛍光体ともいう）は、蛍光体を水などの溶媒に分散させ、その溶媒に溶解するＭｇ，Ｃａ，Ｓｒ，Ｂａ及びＺｎの群から選択された少なくとも１種の金属元素の化合物と、水ガラス、イオン性シリカ成分を含有するコロイド状シリカゾルなど、溶液中で珪酸イオンを遊離する珪素化合物とを化学量論的に、一般式Ｍ_ｍＳｉ_ｎＯ_ｍ _+2ｎで表される珪酸塩（ただし、Ｍは、Ｍｇ，Ｃａ，Ｓｒ，Ｂａ及びＺｎの群から選択される少なくとも１種の金属元素であり、ｍ及びｎは０．１≦（ｍ／ｎ）≦１０を満たす数である、以下同様）となる割合で投入し、十分に攪拌することにより前記金属の珪酸塩が生成し、溶液中の蛍光体表面に付着する。次いで、このスラリーを脱水し、１００〜２００℃で乾燥して真空紫外線用蛍光体は製造される。このようにして得た蛍光体をさらに２００〜１０００℃で焼成することにより、前記珪酸塩に結合している水酸基や付着している水分を除去してもよい。
【００１７】
ここで、蛍光体表面に付着するＭｇ，Ｃａ，Ｓｒ，Ｂａ，Ｚｎの珪酸塩とは、Ｍｇ₂ＳｉＯ₄，Ｃａ₂ＳｉＯ₄，Ｓｒ₂ＳｉＯ₄，Ｂａ₂ＳｉＯ₄，Ｚｎ₂ＳｉＯ₄等のオルト珪酸塩、ＭｇＳｉＯ₃，ＣａＳｉＯ₃，ＳｒＳｉＯ₃，ＢａＳｉＯ₃等のメタ珪酸塩、及びＭｇ₃Ｓｉ₄Ｏ₁₁，ＣａＭｇ（ＳｉＯ₃）₂，ＢａＳｉ₂Ｏ₅などをはじめとする、一般式Ｍ_xＳｉ_yＯ_x+2yで表される珪酸塩をいう。（ただし、Ｍは、Ｍｇ，Ｃａ，Ｓｒ，Ｂａ及びＺｎの群から選択される少なくとも１種の金属元素であり、ｘ及びｙは０．１≦（ｘ／ｙ）≦１０を満たす数である）その中でも、Ｂａ及び／Ｓｒの珪酸塩が焼成時の輝度劣化抑制において特に優れている。
【００１８】
なお、前記蛍光体スラリーにおいて、前記の金属珪酸塩を蛍光体表面に付着して被覆する代わりに、前記の金属珪酸塩粉末と蛍光体を水等の溶媒中で混合した後脱水するか、蛍光体粉末と前記の金属珪酸塩粉末を機械的に混合して、蛍光体への珪酸塩の被覆率や被覆力を高めることも可能であるが、蛍光膜形成における焼成工程での輝度劣化の抑制をより確実にする点では、前記の蛍光体スラリー中で珪酸塩を生成して直接蛍光体に付着する方法の方が優れている。
【００１９】
本発明において、珪酸塩の蛍光体表面への被覆量及び／又は混合量は蛍光体重量に対し、０．０１〜１５重量％の範囲、好ましくは０．０５〜０．５重量％の範囲が適当である。０．０１重量％より少ないと、前記の輝度劣化抑制効果が少なく、逆に１５重量％より多すぎると、蛍光体への励起光の浸透及び蛍光体の発光が前記珪酸塩により阻害され、蛍光体の発光効率が低下するので好ましくない。なお、前記の金属珪酸塩は全量が蛍光体に被覆されていなくてもよいが、その一部は蛍光体表面に付着していることが好ましい。
【００２０】
本発明において使用される真空紫外線用蛍光体は、真空紫外線で励起されて高効率で発光する蛍光体であればよいが、具体的には、一般式（Ｍ¹ _1-xＥｕ_x）Ｏ・ａ（Ｍ² _1-y，Ｍｎ_y）Ｏ・（５．５−０．５ａ）Ａｌ₂Ｏ₃蛍光体（式中、Ｍ¹はＢａ，Ｓｒ及びＣａからなる群より選択される少なくとも１種の元素を表し、Ｍ²はＭｇ及び／又はＺｎを表し、ａは、０＜ａ≦２の実数を表し、ｘ及びｙはそれぞれ０＜ｘ＜１，０≦ｙ＜１の実数を表す）で表されるＥｕ²⁺やＭｎ²⁺で付活されたアルミン酸塩蛍光体、例えばＢａＭｇＡｌ₁₀Ｏ₁₇：Ｅｕ蛍光体、（Ｂａ，Ｓｒ）ＭｇＡｌ₁₀Ｏ₁₇：Ｅｕ，Ｍｎ蛍光体、その他、Ｍｎ²⁺、Ｔｂ³⁺、Ｃｅ³⁺等で付活されたＺｎ₂ＳｉＯ₄：Ｍｎ蛍光体、ＬａＰＯ₄：Ｃｅ，Ｔｂ蛍光体、ＢａＡｌ₁₂Ｏ₁₉：Ｍｎなどの酸化されて原子価の変化し易い元素により付活された蛍光体を挙げることができる。
【００２１】
これらの蛍光体の中で、輝度劣化の改善要望の強い青色発光のＢａＭｇＡｌ₁₀Ｏ₁₇：Ｅｕに代表される、上記一般式（Ｍ¹ _1-xＥｕ_x）Ｏ・ａ（Ｍ² _1-y，Ｍｎ_y）Ｏ・（５．５−０．５ａ）Ａｌ₂Ｏ₃で表されるＥｕ²⁺やＭｎ²⁺で付活されたアルミン酸塩蛍光体において特に有効である。
【００２２】
本発明の蛍光体ペースト組成物は、前記の蛍光体をバインダー樹脂中に分散させて製造する。バインダー樹脂としては、エチルセルロース、ニトロセルロース、アクリル樹脂、ポリスチレンオキサイドなどの樹脂を用い、ブチルカルビトール、ブチルカルビトールアセテート、テルピネオール、酢酸ブチル、酢酸エチル、メチルエチルケトンなどの溶剤とともに均一に混合して分散させる。蛍光体ペースト組成物中の蛍光体の配合量は、５〜８０重量％、好ましくは２０〜６０重量％の範囲が適当である。また、バインダー樹脂の配合量は、４〜８０重量％、好ましくは８〜５０重量％の範囲が適当である。さらに、溶剤の添加量は、１０〜９０重量％、好ましくは４０〜８０重量％の範囲が適当である。
【００２３】
本発明の真空紫外線励起発光素子は、本発明の蛍光体ペースト組成物を例えば４〜１２ｍｍのガラス管内に塗布し、１００〜２００℃で乾燥した後、４００〜８００℃で５〜３０分間焼成し、内壁に蛍光体層を形成し、そのガラス管の両端にニッケルの電極を取り付け、管内を排気して真空にした後、Ｎｅ９８％−Ｘｅ２％の混合ガス、又はＨｅ９８％−Ｘｅ２％の混合ガスなどの希ガスを約５０Ｔｏｒｒの内圧となるように封入して製造する。
【００２４】
【実施例】
〔実施例１〕
（Ｂａ，Ｅｕ）ＭｇＡｌ₁₀Ｏ₁₇蛍光体１００ｇを水２００ｍｌに投入し、混合して十分に攪拌して蛍光体スラリーを調製し、このスラリー中にＺｎ₂ＳｉＯ₄の微粉末を１．１ｇ入れ、攪拌しながら加熱して液量を減らし、最後に蒸発乾固させてＺｎ₂ＳｉＯ₄を前記蛍光体に付着・混合した実施例１の真空紫外線用蛍光体を得た。
【００２５】
〔実施例２〕
（Ｂａ，Ｅｕ）ＭｇＡｌ₁₀Ｏ₁₇蛍光体１００ｇを水３００ｍｌに投入し、混合して十分に攪拌することにより蛍光体スラリーを調製し、このスラリー中にイオン性のＳｉＯ₂を２０％含有するコロイド状のＳｉＯ₂溶液を２ｍｌ滴下し、次いでＺｎを０．５５ｇ含有するＺｎＳＯ₄溶液を滴下し、１５分間攪拌した後、脱水し、１２０℃で５時間かけて乾燥することにより、珪酸亜鉛を前記蛍光体に付着した実施例２の真空紫外線用蛍光体を得た。
【００２６】
〔実施例３〕
実施例１において、Ｚｎ₂ＳｉＯ₂微粉末１．１ｇの代わりに、ＢａＳｉＯ₃・６Ｈ₂Ｏ微粉末２．３ｇを用いた以外は、実施例１と同様にしてＢａＳｉＯ₃・６Ｈ₂Ｏを前記蛍光体に付着・混合した実施例３の真空紫外線用蛍光体を得た。
【００２７】
〔実施例４〕
実施例２において、イオン性ＳｉＯ₂を２０％含有するコロイド状のＳｉＯ₂溶液の滴下量を２ｍｌから４ｍｌに変更し、かつ、Ｚｎを０．５５ｇ含有するＺｎＳＯ₄溶液の代わりに、Ｂａを０．５０ｇ含有するＢａ（ＮＯ₃）₂ 溶液を滴下した以外は、実施例２と同様にして珪酸バリウムを前記蛍光体に付着した実施例４の真空紫外線用蛍光体を得た。
【００２８】
〔実施例５〕
実施例４において、イオン性ＳｉＯ₂を２０％含有するコロイド状のＳｉＯ₂溶液の滴下量を４ｍｌから８ｍｌに変更し、かつ、Ｂａ（ＮＯ₃) ₂ 溶液のＢａの含有量を０．５０ｇから４．５ｇに変更した以外は、実施例４と同様にして珪酸バリウムを前記蛍光体に付着した実施例５の真空紫外線用蛍光体を得た。
【００２９】
〔実施例６〕
実施例４において、イオン性ＳｉＯ₂を２０％含有するコロイド状のＳｉＯ₂溶液の滴下量を４ｍｌから０．８ｍｌに変更し、かつ、Ｂａ（ＮＯ₃) ₂ 溶液のＢａの含有量を０．５０ｇから０．１０ｇに変更した以外は、実施例４と同様にして珪酸バリウムを前記蛍光体に付着した実施例６の真空紫外線用蛍光体を得た。
【００３０】
〔実施例７〕
実施例４において、イオン性ＳｉＯ₂を２０％含有するコロイド状のＳｉＯ₂溶液の滴下量を４ｍｌから０．４ｍｌに変更し、かつ、Ｂａ（ＮＯ₃）₂ 溶液のＢａの含有量を０．５０ｇから０．２３ｇに変更した以外は、実施例４と同様にして珪酸バリウムを前記蛍光体に付着した実施例７の真空紫外線用蛍光体を得た。
【００３１】
〔実施例８〕
実施例４において、イオン性ＳｉＯ₂を２０％含有するコロイド状のＳｉＯ₂溶液の滴下量４ｍｌのまま変更せずに、かつ、Ｂａ（ＮＯ₃) ₂ 溶液の代わりに、Ｓｒを１．５ｇ含有するＳｒ（ＮＯ₃) ₂ 溶液を滴下した以外は、実施例４と同様にして珪酸ストロンチウムを前記蛍光体に付着した実施例８の真空紫外線用蛍光体を得た。
【００３２】
〔実施例９〕
実施例４において、イオン性ＳｉＯ₂を２０％含有するコロイド状のＳｉＯ₂溶液の滴下量を４ｍｌから２ｍｌに変更し、Ｂａ（ＮＯ₃)₂溶液の代わりに、Ｃａを０．３３ｇ含有するＣａ（ＮＯ₃)₂溶液を滴下した以外は、実施例４と同様にして珪酸カルシウムを前記蛍光体に付着した実施例９の真空紫外線用蛍光体を得た。
【００３３】
〔実施例１０〕
実施例４において、イオン性ＳｉＯ₂を２０％含有するコロイド状のＳｉＯ₂溶液の滴下量を４ｍｌから２ｍｌに変更し、Ｂａ（ＮＯ₃)₂溶液の代わりに、Ｍｇを０．２０ｇ含有するＭｇ（ＮＯ₃) ₂ 溶液を滴下した以外は、実施例４と同様にして珪酸マグネシウムを前記蛍光体に付着した実施例１０の真空紫外線用蛍光体を得た。
【００３４】
〔比較例１〕
実施例１〜１０で用いた（Ｂａ，Ｅｕ）ＭｇＡｌ₁₀Ｏ₁₇蛍光体を被覆処理せずにそのまま比較例１の真空紫外線用蛍光体として用いた。
【００３５】
〔比較例２〕
（Ｂａ，Ｅｕ）ＭｇＡｌ₁₀Ｏ₁₇蛍光体１００ｇを水３００ｍｌに投入し、混合して十分に攪拌することにより蛍光体スラリーを調製し、このスラリー中に０．５ｇの（ＮＨ₄) ₂ ＨＰＯ₄を添加して十分に攪拌した後、スラリーを加熱して蒸発乾固して燐酸アンモニウムを蛍光体表面に被覆した比較例２の真空紫外線用蛍光体を得た。
【００３６】
（蛍光体中のＳｉと金属の酸化物換算量の測定）
実施例１〜１０の真空紫外線用蛍光体は、フッ酸を使用して溶解し、誘導結合高周波プラズマ発光分析装置（ＩＣＰ）を用いてＳｉＯ₂、Ｚｎ，Ｂａ，Ｓｒ，Ｃａ，Ｍｇの量を測定して、結果を表１に示した。
【００３７】
（真空紫外線用蛍光体の発光効率の測定）
実施例及び比較例で用いた青色蛍光体の輝度は、その発光色（色度点ｙ値）に比例して大きく変わる。発光色の異なる蛍光体間の発光効率を比較する簡便な方法として輝度をｙ値で割った値（発光効率）で比較することがよく行われる。本評価においても発光効率（輝度／ｙ値）を用い、各蛍光体の焼成処理前における発光効率（▲１▼）と、これらの蛍光体をそれぞれ５５０℃の温度で１時間焼成処理した後の発光効率（▲２▼）を測定し、焼成処理後における輝度維持率（▲２▼／▲１▼）を求めて各蛍光体の焼成処理による発光効率の低下の有無を確認して表１に示した。この時、各蛍光体の発光効率（輝度／ｙ値）は、各蛍光体に対して１４６ｎｍの真空紫外線を照射し、その時の発光輝度と色度（ｙ値）とを測定して求めた。その結果を表１に示した。なお、表１において、各蛍光体の発光効率（輝度／ｙ値）は、表面に何も被覆されていない比較例１の（Ｂａ，Ｅｕ）ＭｇＡｌ₁₀Ｏ₁₇蛍光体の焼成処理前における発光効率（輝度／ｙ値、▲１▼）を１００としたときの相対値で表した。
【００３８】
【表１】

【００３９】
〔実施例１１〜２０〕
実施例１〜１０で得た真空紫外線用蛍光体をそれぞれ３０ｇ秤量し、これにエチルセルロースの樹脂を２５ｇとブチルカルビトール１０ｇ及びブチルカルビトールアセテート５３ｇを混練して実施例１１〜２０の蛍光体ペーストを得た。
【００４０】
〔比較例３〕
実施例１１において、真空紫外線用蛍光体を実施例１のものから比較例１のものに代えた以外は、実施例１１と同様にして比較例３の蛍光体ペーストを得た。
【００４１】
（蛍光体ペーストの評価）
実施例１１〜２０及び比較例３の各蛍光体ペースト組成物をそれぞれガラス板上に０．５ｍｍの厚さに塗布し、１２０℃で６０分間乾燥した後、４５０℃で３０分間焼成処理して蛍光体塗布膜を作製して評価サンプルとした。そして、各評価サンプルに１４６ｎｍの真空紫外線を照射して発光輝度と色度（ｙ値）を測定して発光効率（輝度／ｙ値、▲３▼）を求めて結果を表２に示した。
なお、表２において各評価サンプルの発光効率（▲３▼）は、全て比較例３の蛍光体ペースト組成物に使用した比較例１の（Ｂａ，Ｅｕ）ＭｇＡｌ₁₀Ｏ₁₇蛍光体の焼成処理前の発光効率（輝度／ｙ値、▲１▼）を１００とした時の相対値で示した。
【００４２】
【表２】

【００４３】
表１及び表２の結果から明らかなように、実施例１〜１０の蛍光体は、表面に何も被覆処理が施されていない比較例１の蛍光体や、燐酸アンモニウムで処理された公知の蛍光体即ち比較例２の蛍光体に比べて、蛍光体焼成処理後の発光効率（輝度／ｙ値、▲２▼）はいずれも高く、焼成処理による輝度劣化の程度が大幅に改善されている。特に、Ｂａ，Ｓｒの珪酸塩化合物を被覆又は混合した場合に、蛍光体の焼成処理後の発光効率が高くなり、輝度維持率もより改善された。
【００４４】
また、実施例１〜１０の蛍光体を用いた実施例１１〜２０の蛍光体ペースト組成物の発光効率（輝度／ｙ値、▲３▼）も比較例３の従来の蛍光体ペースト組成物の発光効率（輝度／ｙ値、▲３▼）よりも高く、蛍光膜作製時における焼成処理による輝度劣化の少ない、高輝度の発光効率を示した。
【００４５】
〔実施例２１〕
実施例４で得た真空紫外線用蛍光体を３０ｇ秤量し、これにニトロセルロースの樹脂２５ｇと酢酸ブチル４５ｇを混練して蛍光体ペーストを作製した。この蛍光体ペーストを外径４ｍｍのガラス管内に塗布し、１２０℃で６０分乾燥した後、６００℃で１０分間焼成し、蛍光体塗布管を得た。得られた蛍光体塗布管の両端にニッケルの電極を付け、管内を真空に排気した後、Ｎｅ９８％−Ｘｅ２％のガスを５０Ｔｏｒｒ封入して実施例２１の真空紫外線励起発光素子を作製した。この真空紫外線励起発光素子に１ｋＶの交流電圧を印加して発光させ、真空紫外線励起発光素子の管の中心部の発光効率（輝度／ｙ値）を測定した。
【００４６】
〔比較例４〕
実施例２１において、真空紫外線用蛍光体を実施例４のものから比較例１の蛍光体に代えた以外は、実施例２１と同様にして比較例４の真空紫外線励起発光素子を作製した。そして、実施例２１と同様に交流電圧を印加して発光させ、真空紫外線励起発光素子の管の中心部の発光効率（輝度／ｙ値）を測定した。
【００４７】
（真空紫外線励起発光素子の評価）
比較例４の真空紫外線励起発光素子の管の中心部の発光効率（輝度／ｙ値）を１００％とすると、実施例２１の真空紫外線励起発光素子の管の中心部の発光効率（輝度／ｙ値）は１２１％であった。
【００４８】
【発明の効果】
本発明は、上記の構成を採用することにより、蛍光膜を形成する際の焼成工程における輝度低下を抑制することができ、発光効率の高い蛍光体及び蛍光体ペースト及び発光効率の改善された真空紫外線励起発光素子の提供を可能にした。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a phosphor for a vacuum ultraviolet ray- excited light emitting device that emits light when excited by vacuum ultraviolet ray used for a plasma display panel, a rare gas discharge lamp, and the like, a production method thereof, a phosphor paste composition containing the phosphor, and The present invention relates to a vacuum ultraviolet ray-excited light emitting device including a phosphor film formed using the phosphor paste composition.
[0002]
[Prior art]
In recent years, rare gases such as Ar, Xe, He, Ne, and Xe-Ne are sealed in a vacuum envelope such as glass, and the fluorescent film inside the envelope is formed by vacuum ultraviolet rays emitted by the discharge of the rare gas. Development of a vacuum ultraviolet excitation light emitting element that emits light by excitation is actively performed.
[0003]
One example is a thin tube lamp used as a light source for reading a scanner. The narrow tube is filled with a rare gas such as Xe or Xe-Ne, and a fluorescent film made of a phosphor that emits light when excited by vacuum ultraviolet rays is formed on the inner surface of the tube. When electric energy is applied from the electrodes provided at both ends of the narrow tube, rare gas discharge occurs in the narrow tube, and vacuum ultraviolet rays are emitted. The phosphor is excited by the vacuum ultraviolet rays to emit visible light.
[0004]
The applied phosphor includes a mixture of a single color phosphor that emits red, blue, and green and a phosphor of three colors that emits a single color. The red light emitting phosphor is (Y, Gd) BO ₃ : Eu, the green light emitting phosphor is LaPO ₄ : Ce, Tb, the blue light emitting phosphor is BaMgAl ₁₀ O ₁₇ : Eu, (Ba, Sr) MgAl ₁₀ O ₁₇ : Eu. , Mn, etc. are used.
[0005]
There is a plasma display panel (hereinafter referred to as “PDP”) in addition to the vacuum ultraviolet-excited light emitting element. In principle, the PDP can be thought of as a small-sized vacuum ultraviolet-excited capillary tube and three lamps of different emission colors arranged in a matrix. That is, narrow discharge spaces (hereinafter referred to as “cells”) are arranged in a matrix. Each cell is provided with an electrode, and a phosphor is applied to the inside or outside of each cell to form a phosphor film. Each cell is filled with a rare gas such as Xe or Xe-Ne. When electric energy is applied from the electrode, a rare gas discharge occurs in the cell, and vacuum ultraviolet rays are emitted. The phosphor is excited by the vacuum ultraviolet rays to emit visible light, and an image is displayed by the light emission.
[0006]
In the case of a full-color PDP, full-color display can be performed by coating each phosphor that emits red, blue, and green light by excitation with vacuum ultraviolet rays in a matrix. Here, (Y, Gd) BO ₃ : Eu is used as a red light emitting phosphor, Zn ₂ SiO ₄ : Mn is used as a green light emitting phosphor, BaMgAl ₁₀ O ₁₇ : Eu is used as a blue light emitting phosphor, and the like. (See the Industrial Research Committee, Electronic Materials, December 1997 issue)
[0007]
When a fluorescent film is formed by applying a fluorescent material to both the thin tube lamp and the PDP, a fluorescent material paste in which the fluorescent material is dispersed in a binder resin is used.
In the case of a thin tube lamp, usually a phosphor and a resin such as nitrocellulose are mixed using a solvent such as butyl acetate, applied to the inner surface of the glass tube as a phosphor paste, dried, and then fired. A phosphor coating film is formed on the inner surface.
In the case of PDP, a phosphor, a resin such as ethyl cellulose, and a solvent such as butyl carbitol are mixed to form a phosphor paste, which is applied to the inner surface of the PDP by a screen printing method, dried, and then fired. In general, a phosphor coating film is formed in the PDP cell.
[0008]
Thus, in forming the fluorescent film of the vacuum ultraviolet ray-excited light emitting device, it is essential to apply the phosphor paste composition, dry it, and then fire it. In this firing step, there is a problem that the phosphor deteriorates. Particularly, blue alumina phosphors such as BaMgAl ₁₀ O ₁₇ : Eu, (Ba, Sr) MgAl ₁₀ O ₁₇ : Eu, Mn, etc. are greatly deteriorated in the aluminate phosphor using Eu as an activator, and have high luminance. Even when the light emitting phosphor is used as a device, it is impossible to avoid a decrease in light emission luminance of the blue light emitting component of the obtained vacuum ultraviolet ray excited light emitting device. Therefore, it has been desired to develop a phosphor and a phosphor paste with little deterioration in light emission luminance in the baking process.
[0009]
[Problems to be solved by the invention]
Accordingly, the present invention is to solve the above drawbacks, the deterioration of emission luminance in the step of forming the fluorescent film of the vacuum ultraviolet ray-excited light-emitting device is not small, vacuum ultraviolet ray-excited light-emitting phosphor of high brightness, a method of manufacturing the same, An object of the present invention is to provide a phosphor paste composition and a vacuum ultraviolet ray-excited light emitting device using the same.
[0010]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present inventors have intensively studied the effect of preventing luminance deterioration by coating the surface of a phosphor that emits light by excitation with vacuum ultraviolet rays with various substances. the by coating the divalent metal silicates having found that can suppress the luminance deterioration in the firing step, thereby completing the high-luminance light emission of vacuum ultraviolet ray-excited light-emitting phosphor and a vacuum ultraviolet ray-excited light-emitting element. That is, the configuration of the present invention is as follows.
[0011]
(1) General formula (M ¹ _1-x Eu _x ) O · a (M ² _{_{1-y, Mn y) O}} · (5.5-0.5a) Al 2 O 3 An aluminate phosphor represented by the formula (However, in the general formula, M ¹ Represents at least one element selected from the group consisting of Ba, Sr and Ca, M ² represents Mg and / or Zn, a represents a real number of 0 <a ≦ 2, and x and y represent respectively 0 <x <1, 0 ≦ y <1 represents a real number) is 0.01-15 wt% of a silicate represented by the general formula M _m Si _n O _{m + 2n} with respect to the weight of the aluminate phosphor ( M is at least one metal element selected from the group consisting of Mg, Ca, Sr, Ba and Zn, and m and n are numbers satisfying 0.1 ≦ (m / n) ≦ 10) A phosphor for a vacuum ultraviolet ray- excited light emitting device , characterized by being coated with:
[0012]
(2) vacuum ultraviolet ray-excited light-emitting phosphor according to (1) wherein the value of y and wherein y = 0 der Rukoto.
[0013]
( 3 ) at least one metal compound selected from the group consisting of Mg, Ca, Sr, Ba and Zn dissolved in the solvent in a phosphor slurry in which the aluminate phosphor is dispersed in a solvent; A silicate represented by the general formula M _m Si _n O _m _{+ 2n} stoichiometrically with a silicon compound that liberates silicate ions in solution (where M is Mg, Ca, Sr, Ba and Zn). And at least one metal element selected from the group, and m and n are added at a ratio satisfying 0.1 ≦ ( m / n ) ≦ 10) and mixed to form the silicate of the metal to produce a method for producing a vacuum ultraviolet ray-excited light-emitting phosphor according to (1) or (2), characterized in that the deposition of silicate of said metal to said aluminate phosphor surface.
[0014]
( 4 ) In a phosphor paste composition in which a phosphor is dispersed in a binder resin, the phosphor comprises the phosphor for a vacuum ultraviolet ray excited light-emitting device described in (1) or (2) above. A phosphor paste composition.
[0015]
( 5 ) In a vacuum ultraviolet ray excited light emitting device formed by forming a fluorescent film in a vacuum envelope and enclosing a rare gas, the fluorescent film is for the vacuum ultraviolet ray excited light emitting device according to (1) or (2) . A vacuum ultraviolet-excited light emitting device comprising a phosphor.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
The phosphor for a vacuum ultraviolet ray- excited light emitting device of the present invention (hereinafter also referred to as a vacuum ultraviolet phosphor) is made of Mg, Ca, Sr, Ba and Zn which are dispersed in a solvent such as water and dissolved in the solvent. Stoichiometrically, a compound of at least one metal element selected from the group and a silicon compound that liberates silicate ions in solution, such as water glass, colloidal silica sol containing an ionic silica component Silicate represented by M _m Si _n O _m _{+2 n} (where M is at least one metal element selected from the group consisting of Mg, Ca, Sr, Ba and Zn, and m and n are 0 .. 1 ≦ ( m / n ) ≦ 10 (the same applies hereinafter), and when sufficiently stirred, the metal silicate is formed and adheres to the phosphor surface in the solution. . Next, the slurry is dehydrated and dried at 100 to 200 ° C. to produce a vacuum ultraviolet phosphor. The phosphor thus obtained may be further baked at 200 to 1000 ° C. to remove hydroxyl groups bonded to the silicate and adhering moisture.
[0017]
Here, Mg, Ca, Sr, Ba, Zn silicate adhering to the phosphor surface is Mg ₂ SiO ₄ , Ca ₂ SiO ₄ , Sr ₂ SiO ₄ , Ba ₂ SiO ₄ , Zn ₂ SiO ₄ or the like. General formula M _x including orthosilicate, metasilicate such as MgSiO ₃ , CaSiO ₃ , SrSiO ₃ , BaSiO ₃ , Mg ₃ Si ₄ O ₁₁ , CaMg (SiO ₃ ) ₂ , BaSi ₂ O ₅ It refers to a silicate represented by Si _y O _{x + 2y} . (However, M is at least one metal element selected from the group consisting of Mg, Ca, Sr, Ba and Zn, and x and y are numbers satisfying 0.1 ≦ (x / y) ≦ 10. Among these, Ba and / Sr silicates are particularly excellent in suppressing luminance deterioration during firing.
[0018]
In the phosphor slurry, instead of depositing and coating the metal silicate on the phosphor surface, the metal silicate powder and the phosphor are mixed in a solvent such as water and then dehydrated or fluorescent. It is possible to mechanically mix the body powder and the above metal silicate powder to increase the coverage and covering power of the silicate on the phosphor. In the point which makes it more reliable, the method of producing | generating a silicate in the said phosphor slurry and adhering to a phosphor directly is superior.
[0019]
In the present invention, the coating amount and / or mixing amount of the silicate on the phosphor surface is in the range of 0.01 to 15% by weight, preferably in the range of 0.05 to 0.5% by weight, based on the weight of the phosphor. Is appropriate. If the amount is less than 0.01% by weight, the effect of suppressing the luminance deterioration is small. On the other hand, if the amount is more than 15% by weight, penetration of excitation light into the phosphor and emission of the phosphor are inhibited by the silicate, and fluorescence This is not preferable because the luminous efficiency of the body is lowered. In addition, although the whole quantity of the said metal silicate does not need to be coat | covered with the fluorescent substance, it is preferable that the one part has adhered to the fluorescent substance surface.
[0020]
The phosphor for vacuum ultraviolet rays used in the present invention may be any phosphor that is excited by vacuum ultraviolet rays and emits light with high efficiency. Specifically, the phosphor of the general formula (M ¹ _1-x Eu _x ) O. ^{_{_{a (M 2 1-y,}}} Mn y) O · (5.5-0.5a) Al 2 O 3 phosphor (wherein, at least one M ¹ is selected from the group consisting of Ba, Sr and Ca M ² represents Mg and / or Zn, a represents a real number of 0 <a ≦ 2, and x and y represent a real number of 0 <x <1, 0 ≦ y <1, respectively) An aluminate phosphor activated by Eu ²⁺ or Mn ²⁺ represented by, for example, BaMgAl ₁₀ O ₁₇ : Eu phosphor, (Ba, Sr) MgAl ₁₀ O ₁₇ : Eu, Mn phosphor, Zn ₂ SiO ₄ : Mn phosphor activated by Mn ²⁺ , Tb ³⁺ , Ce ³⁺ , LaPO ₄ : Ce, Tb phosphor, BaAl ₁₂ O ₁₉ : A phosphor activated by an element which is easily oxidized and changes its valence, such as Mn.
[0021]
Among these phosphors, the above general formula (M ¹ _1-x Eu _x ) O · a (M ² _1-y typified by blue light-emitting BaMgAl ₁₀ O ₁₇ : Eu, which is strongly desired to improve luminance degradation. is particularly effective in _{Mn y) O · (5.5-0.5a)} Al 2 O 3 with Eu ²⁺ and Mn ²⁺ activated with aluminate phosphor represented.
[0022]
The phosphor paste composition of the present invention is produced by dispersing the aforementioned phosphor in a binder resin. As binder resin, use resin such as ethyl cellulose, nitrocellulose, acrylic resin, polystyrene oxide, and uniformly mix and disperse with solvent such as butyl carbitol, butyl carbitol acetate, terpineol, butyl acetate, ethyl acetate, methyl ethyl ketone. . The blending amount of the phosphor in the phosphor paste composition is 5 to 80% by weight, preferably 20 to 60% by weight. Further, the blending amount of the binder resin is 4 to 80% by weight, preferably 8 to 50% by weight. Furthermore, the amount of the solvent added is 10 to 90% by weight, preferably 40 to 80% by weight.
[0023]
The vacuum ultraviolet ray-excited light emitting device of the present invention is obtained by applying the phosphor paste composition of the present invention to a glass tube of 4 to 12 mm, for example, and drying at 100 to 200 ° C., followed by baking at 400 to 800 ° C. for 5 to 30 minutes. A phosphor layer is formed on the inner wall, nickel electrodes are attached to both ends of the glass tube, the inside of the tube is evacuated and evacuated, and then a mixed gas of Ne 98% -Xe 2% or a mixed gas of He 98% -Xe 2% A noble gas such as is sealed and manufactured so as to have an internal pressure of about 50 Torr.
[0024]
【Example】
[Example 1]
100 g of (Ba, Eu) MgAl ₁₀ O ₁₇ phosphor is put into 200 ml of water, mixed and sufficiently stirred to prepare a phosphor slurry, and 1.1 g of Zn ₂ SiO ₄ fine powder is put into this slurry. The phosphor was reduced in volume by heating with stirring, and finally evaporated to dryness to obtain a phosphor for vacuum ultraviolet ray of Example 1 in which Zn ₂ SiO ₄ was adhered and mixed with the phosphor.
[0025]
[Example 2]
A phosphor slurry is prepared by putting 100 g of (Ba, Eu) MgAl ₁₀ O ₁₇ phosphor in 300 ml of water, mixing and stirring sufficiently, and a colloid containing 20% of ionic SiO ₂ in the slurry. 2 ml of a SiO ₂ solution in the form of a drop was added, and then a ZnSO ₄ solution containing 0.55 g of Zn was added dropwise, stirred for 15 minutes, dehydrated, and dried at 120 ° C. for 5 hours. The phosphor for vacuum ultraviolet ray of Example 2 adhered to the phosphor was obtained.
[0026]
Example 3
In Example 1, BaSiO ₃ .6H ₂ O was added in the same manner as in Example 1 except that 2.3 g of BaSiO ₃ .6H ₂ O fine powder was used instead of 1.1 g of Zn ₂ SiO ₂ fine powder. A phosphor for vacuum ultraviolet ray of Example 3 adhered to and mixed with the phosphor was obtained.
[0027]
Example 4
In Example 2, the drop amount of the colloidal SiO ₂ solution containing 20% ionic SiO ₂ was changed from 2 ml to 4 ml, and instead of the ZnSO ₄ solution containing 0.55 g Zn, Ba was changed to 0. except that dropwise Ba (NO ₃₎ ₂ solution containing .50g got VUV phosphor of example 4 a barium silicate in the same manner as in example 2 was adhered to the phosphor.
[0028]
Example 5
In Example 4, the dropping amount of the colloidal SiO ₂ solution containing 20% ionic SiO ₂ was changed from 4 ml to 8 ml, and the Ba content of the Ba (NO ₃ ) ₂ solution was changed from 0.50 g. Except having changed into 4.5 g, it carried out similarly to Example 4, and obtained the fluorescent substance for vacuum ultraviolet rays of Example 5 which adhered barium silicate to the said fluorescent substance.
[0029]
Example 6
In Example 4, the dropping amount of the colloidal SiO ₂ solution containing 20% ionic SiO ₂ was changed from 4 ml to 0.8 ml, and the Ba content of the Ba (NO ₃ ) ₂ solution was changed to 0.1. Except for changing from 50 g to 0.10 g, a phosphor for vacuum ultraviolet ray of Example 6 in which barium silicate was adhered to the phosphor was obtained in the same manner as Example 4.
[0030]
Example 7
In Example 4, the dropping amount of the colloidal SiO ₂ solution containing 20% ionic SiO ₂ was changed from 4 ml to 0.4 ml, and the Ba content of the Ba (NO ₃ ) ₂ solution was changed to 0.1. Except for changing from 50 g to 0.23 g, a phosphor for vacuum ultraviolet ray of Example 7 in which barium silicate was adhered to the phosphor was obtained in the same manner as Example 4.
[0031]
Example 8
In Example 4, the drop amount of colloidal SiO ₂ solution containing 20% ionic SiO ₂ remains unchanged at 4 ml, and 1.5 g of Sr is contained instead of the Ba (NO ₃ ) ₂ solution. Except that the Sr (NO ₃ ) ₂ solution was dropped, a phosphor for vacuum ultraviolet ray of Example 8 in which strontium silicate was adhered to the phosphor was obtained in the same manner as Example 4.
[0032]
Example 9
In Example 4, the dropping amount of colloidal SiO ₂ solution containing ionic SiO ₂ 20% change from 4ml to 2ml, Ba (NO ₃₎ in place of ₂ solutions, that 0.33g containing Ca Ca Except that the (NO ₃ ) ₂ solution was dropped, a phosphor for vacuum ultraviolet ray of Example 9 in which calcium silicate was adhered to the phosphor was obtained in the same manner as Example 4.
[0033]
Example 10
In Example 4, the dropping amount of colloidal SiO ₂ solution containing ionic SiO ₂ 20% change from 4ml to 2ml, Ba (NO ₃₎ in place of ₂ solutions, that 0.20g containing Mg Mg Except that the (NO ₃ ) ₂ solution was added dropwise, a vacuum ultraviolet phosphor of Example 10 in which magnesium silicate was adhered to the phosphor was obtained in the same manner as in Example 4.
[0034]
[Comparative Example 1]
The (Ba, Eu) MgAl ₁₀ O ₁₇ phosphor used in Examples 1 to 10 was used as the phosphor for vacuum ultraviolet ray of Comparative Example 1 without being coated.
[0035]
[Comparative Example 2]
A phosphor slurry is prepared by putting 100 g of (Ba, Eu) MgAl ₁₀ O ₁₇ phosphor into 300 ml of water, mixing and thoroughly stirring, and 0.5 g of (NH ₄ ) ₂ HPO _{4 in} this slurry. Was added and sufficiently stirred, and the slurry was heated and evaporated to dryness to obtain a phosphor for vacuum ultraviolet ray of Comparative Example 2 in which ammonium phosphate was coated on the phosphor surface.
[0036]
(Measurement of oxide equivalent amount of Si and metal in phosphor)
The phosphors for vacuum ultraviolet rays of Examples 1 to 10 were dissolved using hydrofluoric acid, and the amounts of SiO ₂ , Zn, Ba, Sr, Ca, and Mg were measured using an inductively coupled high-frequency plasma emission analyzer (ICP). The results are shown in Table 1.
[0037]
(Measurement of luminous efficiency of phosphor for vacuum ultraviolet ray)
The luminance of the blue phosphor used in the examples and comparative examples varies greatly in proportion to the emission color (chromaticity point y value). As a simple method for comparing the luminous efficiencies between phosphors having different emission colors, the luminance is often compared by a value obtained by dividing the luminance by the y value (luminous efficiency). Also in this evaluation, the luminous efficiency (luminance / y value) was used, the luminous efficiency before firing of each phosphor ((1)), and after these phosphors were fired at a temperature of 550 ° C. for 1 hour, respectively. The luminous efficiency ((2)) was measured, and the luminance maintenance ratio ((2) / (1)) after the baking treatment was determined to confirm whether or not the luminous efficiency was reduced by the firing treatment of each phosphor. Indicated. At this time, the luminous efficiency (luminance / y value) of each phosphor was obtained by irradiating each phosphor with vacuum ultraviolet light of 146 nm and measuring the luminous luminance and chromaticity (y value) at that time. The results are shown in Table 1. In Table 1, the luminous efficiency (luminance / y value) of each phosphor is the luminous efficiency before firing of the (Ba, Eu) MgAl ₁₀ O ₁₇ phosphor of Comparative Example 1 in which nothing is coated on the surface. Expressed as a relative value when (luminance / y value, (1)) is 100.
[0038]
[Table 1]

[0039]
[Examples 11 to 20]
30 g of each vacuum ultraviolet phosphor obtained in Examples 1 to 10 was weighed, and 25 g of ethyl cellulose resin, 10 g of butyl carbitol and 53 g of butyl carbitol acetate were kneaded therein, and the phosphor pastes of Examples 11 to 20 Got.
[0040]
[Comparative Example 3]
In Example 11, the phosphor paste of Comparative Example 3 was obtained in the same manner as Example 11 except that the vacuum ultraviolet phosphor was changed from that of Example 1 to that of Comparative Example 1.
[0041]
(Evaluation of phosphor paste)
Each phosphor paste composition of Examples 11 to 20 and Comparative Example 3 was applied to a glass plate to a thickness of 0.5 mm, dried at 120 ° C. for 60 minutes, and then baked at 450 ° C. for 30 minutes. A phosphor coating film was prepared and used as an evaluation sample. Each evaluation sample was irradiated with vacuum ultraviolet rays of 146 nm, and the luminance and chromaticity (y value) were measured to obtain luminous efficiency (luminance / y value, (3)). The results are shown in Table 2.
In Table 2, the luminous efficiencies ((3)) of the respective evaluation samples are all before the firing treatment of the (Ba, Eu) MgAl ₁₀ O ₁₇ phosphor of Comparative Example 1 used for the phosphor paste composition of Comparative Example 3. The light emission efficiency (luminance / y value, {circle around (1)}) of 100 was shown as a relative value.
[0042]
[Table 2]

[0043]
As is clear from the results of Tables 1 and 2, the phosphors of Examples 1 to 10 are the phosphors of Comparative Example 1 whose surface is not subjected to any coating treatment, and known phosphors treated with ammonium phosphate. Compared with the phosphor, that is, the phosphor of Comparative Example 2, the luminous efficiency (luminance / y value, (2)) after the phosphor firing treatment is high, and the degree of luminance deterioration due to the firing treatment is greatly improved. . In particular, when a silicate compound of Ba or Sr is coated or mixed, the luminous efficiency after the phosphor is baked is increased, and the luminance maintenance rate is further improved.
[0044]
Moreover, the luminous efficiency (luminance / y value, (3)) of the phosphor paste compositions of Examples 11 to 20 using the phosphors of Examples 1 to 10 is also that of the conventional phosphor paste composition of Comparative Example 3. The luminous efficiency was higher than the luminous efficiency (luminance / y value, (3)), and the luminous efficiency was high with little luminance deterioration due to the baking treatment during the production of the phosphor film.
[0045]
Example 21
30 g of the vacuum ultraviolet phosphor obtained in Example 4 was weighed, and 25 g of nitrocellulose resin and 45 g of butyl acetate were kneaded to prepare a phosphor paste. This phosphor paste was applied in a glass tube having an outer diameter of 4 mm, dried at 120 ° C. for 60 minutes, and then baked at 600 ° C. for 10 minutes to obtain a phosphor coated tube. Nickel electrodes were attached to both ends of the obtained phosphor-coated tube, and the inside of the tube was evacuated. Then, a Ne98% -Xe2% gas was sealed in 50 Torr to produce a vacuum ultraviolet ray excited light emitting device of Example 21. A 1 kV alternating voltage was applied to the vacuum ultraviolet light excited light emitting element to emit light, and the light emission efficiency (luminance / y value) at the center of the tube of the vacuum ultraviolet light excited light emitting element was measured.
[0046]
[Comparative Example 4]
In Example 21, a vacuum ultraviolet light-excited light emitting device of Comparative Example 4 was produced in the same manner as in Example 21, except that the vacuum ultraviolet phosphor was changed from that of Example 4 to the phosphor of Comparative Example 1. Then, in the same manner as in Example 21, light was emitted by applying an AC voltage, and the light emission efficiency (luminance / y value) at the center of the tube of the vacuum ultraviolet ray excited light emitting element was measured.
[0047]
(Evaluation of vacuum ultraviolet-excited light emitting device)
If the luminous efficiency (luminance / y value) of the central portion of the tube of the vacuum ultraviolet ray excited light emitting element of Comparative Example 4 is 100%, the luminous efficiency (luminance / y of the central portion of the tube of the vacuum ultraviolet ray excited light emitting element of Example 21 is assumed. Value) was 121%.
[0048]
【The invention's effect】
In the present invention, by adopting the above-described configuration, it is possible to suppress a decrease in luminance in the firing step when forming the phosphor film, and a phosphor and phosphor paste having high luminous efficiency and a vacuum with improved luminous efficiency. An ultraviolet-excited light emitting device can be provided.

Claims

General formula (M ¹ _1-x Eu _x ) O · a (M ² _{_{1-y, Mn y) O}} · (5.5-0.5a) Al 2 O 3 An aluminate phosphor represented by the formula (However, in the general formula, M ¹ Represents at least one element selected from the group consisting of Ba, Sr and Ca, M ² represents Mg and / or Zn, a represents a real number of 0 <a ≦ 2, and x and y represent respectively 0 <x <1, 0 ≦ y <1 representing a real number)
Silicates represented by the general formula M _m Si _n O _{m + 2} n of 0.01 to 15 wt% with respect to the weight of the aluminate phosphor (where M is a group of Mg, Ca, Sr, Ba and Zn) At least one metal element selected, and m and n are covered with 0.1 ≦ ( m / n ) ≦ 10)
A phosphor for a vacuum ultraviolet ray- excited light-emitting element .

Vacuum ultraviolet ray-excited light-emitting phosphor according to claim 1, wherein the value of y and wherein y = 0 der Rukoto.

In a phosphor slurry in which the aluminate phosphor is dispersed in a solvent, in a solution, at least one metal compound selected from the group of Mg, Ca, Sr, Ba and Zn dissolved in the solvent And a silicate represented by the general formula M _m Si _n O _m _{+ 2n} (where M is selected from the group of Mg, Ca, Sr, Ba and Zn). at least one metal element, m and n are to produce a silicate of the metal by adding and mixing ratio to form a number) satisfying 0.1 ≦ (m / n) ≦ 10 the method of vacuum ultraviolet ray-excited light-emitting phosphor according to claim 1 or 2, characterized in that the deposition of silicate of said metal to said aluminate phosphor surface.

A phosphor paste composition in which a phosphor is dispersed in a binder resin, wherein the phosphor comprises the phosphor for a vacuum ultraviolet ray- excited light emitting device according to claim 1 or 2 . .

Fluorescent film is formed on the vacuum outside the enclosure, the vacuum ultraviolet ray-excited light-emitting device formed by sealing a rare gas, said phosphor layer consisting of vacuum ultraviolet ray-excited light-emitting phosphor according to claim 1 or 2 A vacuum ultraviolet-excited light emitting device characterized.