JP3877618B2

JP3877618B2 - Gas discharge tube and display device using the same

Info

Publication number: JP3877618B2
Application number: JP2002072663A
Authority: JP
Inventors: 章渡海; 斉山田; 学石本; 健司粟本; 傳篠田
Original assignee: Fujitsu Ltd
Current assignee: Fujitsu Ltd
Priority date: 2002-03-15
Filing date: 2002-03-15
Publication date: 2007-02-07
Anticipated expiration: 2022-03-15
Also published as: JP2003272561A

Description

【０００１】
【発明の属する技術分野】
本発明は、ガス放電管に関し、さらに詳しくは、直径０．５〜５ｍｍ程度の細管を用いたガス放電管に関する。
【０００２】
【従来の技術】
ガス放電管を並列に複数配列して、任意の画像を表示する表示装置が知られている。この表示装置のガス放電管では、直径０．５〜５ｍｍ程度の細管を用いる。
【０００３】
従来、このような細管を用いたガス放電管では、細管の内面に、ある値以上のエネルギーを有する放電ガスとの衝突により荷電粒子を発生し、放電開始電圧を下げる機能をもつ電子放出膜、例えばＭｇＯ膜を形成する場合、細管の内面に、例えば脂肪酸マグネシウムの溶液をスピンコート法などで塗布し、その塗布層を焼成することで形成するようにしている。
【０００４】
この場合、細管が短かければ（ほぼ３００ｍｍ以下）、細管の内面にＭｇＯ膜を比較的均一に塗布することができる。また、塗布層の焼成を行う際、細管の内径が十分に大きい（４ｍｍ以上）と、細管内への空気導入に対して抵抗が少なく（通気コンダクタンスが高い）、焼成を行いやすい。
【０００５】
【発明が解決しようとする課題】
しかしながら、細管の長さが３００ｍｍを超えるものになると、スピンコート法で細管の内面にＭｇＯ膜を均一に塗布することは困難である。また、細管の内径が２ｍｍ以下になると、塗布層の焼成を行う際、細管の内部で脂肪酸マグネシウムの有機成分の燃焼に必要な酸素が不足し、このため有機成分が完全に除去されず、ＭｇＯ膜の光透過率が低下する。
【０００６】
したがって、内径が２ｍｍ以下、あるいは長さが３００ｍｍ以上の細管であっても、細管の内面に電子放出膜を容易に形成できるような技術の出現が望まれていた。
【０００７】
本発明は、このような事情を考慮してなされたもので、電子放出膜を細管とは別体の支持部材に形成し、この支持部材を細管の内部に配置することで、電子放出膜の形成を容易にすることを目的とするものである。
【０００８】
【課題を解決するための手段】
本発明は、放電空間を形成する細管の内部に電子放出膜を有したガス放電管において、前記細管と独立した支持部材に、脂肪酸マグネシウムの溶液が塗布されて焼成されることで電子放出膜があらかじめ形成された後、当該支持部材が前記細管の内部に挿入されて放電空間内に配置されてなるガス放電管である。
【０００９】
本発明によれば、細管の外部で電子放出膜を支持部材に形成し、その支持部材を細管の内部に挿入して放電空間内に配置することができる。したがって、例えば、支持部材を、細管よりも短い複数の筒形状の部材で構成したり、半筒形状の部材で構成することにより、電子放出膜形成用の塗布液を均一に塗布することができる。また、その塗布膜の焼成の際の酸素不足による焼きむらを防止することができる。これにより良好な電子放出膜を容易に形成することが可能となる。
【００１０】
【発明の実施の形態】
本発明のガス放電管は、どのような径の細管を用いて形成されてもよいが、特に直径０．５〜５ｍｍ程度の細管を用いて好ましくは形成される。この細管は、円形の断面を有していることが好ましいが、扁平楕円状の断面を有していてもよい。
【００１１】
本発明は、例えば細管の両端を封止することによって細管の内部に放電空間を形成し、その放電空間内に電子放出膜を配置した構成である。そして、その電子放出膜の配置においては、電子放出膜を細管と独立した支持部材に形成し、その支持部材を細管の内部に挿入することによって、電子放出膜を放電空間内に位置付ける。
【００１２】
細管の内径が小さい場合、細管の内部の通気性が悪く、細管の内面に電子放出膜を形成しようとしても、細管の内面に塗布した電子放出膜形成用の塗布膜の焼成時に十分に空気が供給されない。そこで、本発明では、細管の内部に挿入できるような支持部材に電子放出膜を形成する。つまり、電子放出膜を細管内で形成するのではなく、細管の外部で形成して、その後細管の内部に導入できる構造としている。
【００１３】
本発明において、支持部材には電子放出膜が形成される。この電子放出膜は、ＭｇＯ、ＣａＯ、ＳｒＯ、ＢａＯ等からなる。
支持部材は、細管と独立した形状であればよく、特に限定されないが、細管よりも短い複数の筒形状の部材、または筒を長手方向に割った半筒形状（以下、ボート形状ともいう）の部材とすることが望ましい。この支持部材は、電子放出膜の形成面で放電を発生させるため、誘電体で構成することが望ましい。
【００１４】
本発明においては、細管と独立した支持部材に形成された蛍光体層をさらに備えていてもよく、この場合、電子放出膜の支持部材が筒形状であれば、この蛍光体層の支持部材を電子放出膜の支持部材の内部に挿入して放電空間内に配置した構成とすることが望ましい。
【００１５】
また、電子放出膜の支持部材が、筒を長手方向に割った半円形の断面を有するボート形状で、蛍光体層の支持部材もそれと同じ形状であれば、それぞれ半筒形の電子放出膜の支持部材と蛍光体層の支持部材を、円筒形となるように両者を向き合わせ、細管の内部に挿入して放電空間内に配置した構成とすることが望ましい。この場合、電子放出膜の支持部材と蛍光体層の支持部材とが向き合わされた断面は円形であり、両者はともに半分の円弧の断面形状であるが、これに限定されず、一方の円弧が大きく、他方の円弧が小さい形状であってもよい。
【００１６】
支持部材の材料としては、ガラスを用いることが望ましい。ガラスを用いた場合には、細管がガラス等であれば、細管内に放電ガスを導入して細管の端部を封止する際に、支持部材を細管と一緒に溶融させてチップオフ（溶断）することで、支持部材を細管内に固定することができる。この場合、互いのガラスがなじむため、細管のリーク等の発生を防止することができる。支持部材の細管内への固定については、この他に低融点ガラスのような接着剤を用いて固定するようにしてもよい。
【００１７】
本発明は、また、上記したガス放電管を、支持基板上に複数本並設し、前記支持基板のガス放電管設置面に、当該ガス放電管の外壁面と接してその長手方向に沿う複数の信号電極を形成し、前記ガス放電管の表面側の外壁面に接して各ガス放電管を横切る方向の表示電極対を設けてなる表示装置である。
【００１８】
以下、図面に示す実施の形態に基づいてこの発明を詳述する。なお、この発明はこれによって限定されるものではなく、各種の変形が可能である。
本発明のガス放電管は、ガス放電管を複数本並列に配置して、任意の画像を表示する表示装置に好適に用いられる。この表示装置の一例を説明する。
【００１９】
図１は本発明のガス放電管を用いた表示装置の一例を示す説明図である。
図において、３１は前面側の基板、３２は背面側の基板、１はガス放電管、２は表示電極対（主電極対）、３は信号電極（データ電極ともいう）である。
【００２０】
細管状のガス放電管１の内部（放電空間）には、電子放出膜を形成した支持部材（以下、電子放出膜の支持部材という）と蛍光体層を形成した支持部材（以下、蛍光体層の支持部材という）とが挿入されて配置され、放電ガスが導入されて、両端が封止されている。信号電極３は背面側の基板３２に形成され、ガス放電管１の長手方向に沿って設けられている。表示電極対２は前面側の基板３１に形成され、信号電極３と交差する方向に設けられている。表示電極対２と表示電極対２との間には、非放電領域（非放電ギャップ）２１が設けられている。
【００２１】
信号電極３と表示電極対２は、組み立て時にガス放電管１の下側の外周面と上側の外周面にそれぞれ密着するように接触させるが、その密着性を良くするために、表示電極とガス放電管面との間に接着剤を介在させて接着してもよい。
【００２２】
この表示装置を平面的にみた場合、信号電極３と表示電極対２との交差部が単位発光領域となる。表示は、表示電極対２のいずれか一本を走査電極として用い、その走査電極と信号電極３との交差部で選択放電を発生させて発光領域を選択し、その発光に伴って当該領域の管内面に形成された壁電荷を利用して、表示電極対２で表示放電を発生させることで行う。選択放電は、上下方向に対向する走査電極と信号電極３との間のガス放電管１内で発生される対向放電であり、表示放電は、平面上に平行に配置される２本の表示電極間のガス放電管１内で発生される面放電である。
【００２３】
図の電極構造では、一つの発光部位に３つの電極が配置された構成であり、表示電極対によって表示放電が発生される構造であるが、この限りではなく、表示電極２と信号電極３との間で表示放電が発生される構造であってもよい。
【００２４】
すなわち、表示電極対２を一本とし、この表示電極２を走査電極として用いて信号電極３との間に選択放電と表示放電（対向放電）を発生させる形式の電極構造であってもよい。
【００２５】
図２はガス放電管の実施形態１の構成を示す説明図である。図はガス放電管の長手方向に直交する断面を示している。図において、１ａはガス放電管となる細管、４は電子放出膜の支持部材、５は蛍光体層の支持部材である。
【００２６】
本形態では、細管１ａは、円形の断面を有しており、ホウケイ酸ガラスを用い、管の外径１０００μｍ、肉厚６０μｍ、長さ４００ｍｍで作製している。細管１ａの内部には、電子放出膜の支持部材４が配置され、この電子放出膜の支持部材４の内部には、蛍光体層の支持部材５が配置されている。電子放出膜の支持部材４と蛍光体層の支持部材５もホウケイ酸ガラスで作製している。
【００２７】
細管１ａは、細管１ａと相似形の大形の母材をダンナー法で作製し、それを加熱して軟化させながら、リドロー（引き伸ばし）することにより作製する。電子放出膜の支持部材４と蛍光体層の支持部材５も同様の方法で作製する。なお、これらはリドローではなく、最終的な形状のものを加熱プレスで直接形成するようにしてもよい。
【００２８】
電子放出膜の支持部材４は、細管１ａよりもひと回り小さい円形の断面を有しており、管の外径８６０μｍ、肉厚６０μｍ、長さ２００ｍｍで作製している。電子放出膜の支持部材４の内面には、電子放出膜としてのＭｇＯ膜４ａを０．１〜１μｍの膜厚で形成している。ＭｇＯ膜４ａは、細管１ａ内に電子放出膜の支持部材４を挿入する前に、支持部材４の内面に形成しておく。
【００２９】
このＭｇＯ膜４ａは、支持部材４の内面に脂肪酸マグネシウムの溶液をスピンコート法で塗布して乾燥させた後、その塗布層を焼成することで形成する。
【００３０】
電子放出膜の支持部材４は、長さが２００ｍｍであるので、支持部材４の内面に脂肪酸マグネシウム溶液を均一に塗布することができる。また、この長さであれば、焼成時に、支持部材４の内部で、脂肪酸マグネシウムの有機成分の燃焼に必要な酸素が不足することがないので、焼成後のＭｇＯ膜に光透過率の低下がない。これにより、支持部材４の内面に良好なＭｇＯ膜を均一に形成することができる。
【００３１】
蛍光体層の支持部材５は、外径７２０μｍの円筒を長手方向に２つに割ったボート形状で、半円形の断面を有しており、肉厚６０μｍ、長さ２００ｍｍで作製している。蛍光体層の支持部材５の凹部には、蛍光体層５ａを２０〜３０μｍの厚みで形成している。蛍光体層５ａは、蛍光体層の支持部材５を電子放出膜の支持部材４内に挿入する前に、支持部材５の凹部に形成しておく。
【００３２】
蛍光体層５ａは、フルカラーの表示に必要なＲ（赤）、Ｇ（緑）、Ｂ（青）の蛍光体の内のいずれか一色の蛍光体で形成する。この蛍光体層５ａは、当該分野で公知の蛍光体を用い、この蛍光体を含むペーストを支持部材５の凹部に塗布して乾燥させた後、焼成することにより形成する。
【００３３】
蛍光体層５ａは、細管１ａと電子放出膜の支持部材５の外部で形成するので、蛍光体を含むペーストを支持部材５の凹部に塗布した後、焼成しても、酸素不足になることがなく、有機成分を完全に焼失させることができる。
【００３４】
このガス放電管では、構造が、細管１ａと電子放出膜の支持部材４との二重構造であるので、細管と電子放出膜の支持部材との合計の肉厚を、一重構造の場合の細管の肉厚と同じ程度にする必要がある。
【００３５】
図３はガス放電管の実施形態２の構成を示す説明図である。図はガス放電管の長手方向に直交する断面を示している。図において、６は電子放出膜の支持部材、７は蛍光体層の支持部材である。
【００３６】
本形態において、細管１ａは実施形態１と同じものである。細管１ａの内部には、電子放出膜の支持部材６と蛍光体層の支持部材７が配置されている。電子放出膜の支持部材６と蛍光体層の支持部材７もホウケイ酸ガラスを用い、リドローにより作製している。
【００３７】
電子放出膜の支持部材６は、外径８６０μｍの円筒を長手方向に２つに割ったボート形状であり、肉厚６０μｍ、長さ２００ｍｍで作製している。電子放出膜の支持部材６の凹部には、電子放出膜としてのＭｇＯ膜６ａを０．１〜１μｍの膜厚で形成している。ＭｇＯ膜６ａは、細管１ａ内に電子放出膜の支持部材６を挿入する前に、支持部材６の凹部に形成しておく。
【００３８】
このＭｇＯ膜６ａは、支持部材６の凹部に脂肪酸マグネシウムの溶液をスロットコート法やスピンコート法などで塗布して乾燥させた後、その塗布層を焼成することで形成する。
【００３９】
電子放出膜の支持部材６は、ボート形状であるので、３００ｍｍを超えるような長さの支持部材であっても脂肪酸マグネシウム溶液の均一な塗布が可能である。また、脂肪酸マグネシウムの塗布層の焼成時に酸素不足となることがないので、焼成後のＭｇＯ膜に光透過率の低下がない。これにより、支持部材６の凹部に良好なＭｇＯ膜を均一に形成することができる。
【００４０】
さらに、電子放出膜の支持部材６がボート形状であるので、脂肪酸マグネシウム溶液のような塗布液を用いた熱分解法でＭｇＯ膜を形成するのではなく、蒸着などの方法でもＭｇＯ膜を形成することができる。
【００４１】
蛍光体層の支持部材７は、電子放出膜の支持部材６と同じ形状であり、蛍光体層の支持部材７の凹部には、実施形態１と同じ方法で、蛍光体層７ａを２０〜３０μｍの厚みで形成している。蛍光体層７ａは、蛍光体層の支持部材７を細管１ａ内に挿入する前に、支持部材７の凹部に形成しておく。
【００４２】
本形態でも、蛍光体層７ａは、細管１ａの外部で形成するので、蛍光体を含むペーストを支持部材７の凹部に塗布した後、焼成しても、酸素不足になることがなく、有機成分を完全に焼失させることができる。
【００４３】
このガス放電管でも、構造が、細管１ａと、電子放出膜の支持部材６と蛍光体層の支持部材７とで形成される管構造との二重構造であるので、細管と電子放出膜の支持部材との合計の肉厚を、一重構造の場合の細管の肉厚と同じ程度にする必要がある。
【００４４】
図４は上述のガス放電管を用いて表示装置を構成した例を示す説明図である。この図は、図１で示した表示装置を平面的に見た状態を示している。
本例では、表示電極対２は、それぞれ透明電極２ａとバス電極２ｂで構成している。信号電極は示していない。細管１ａは、Ｒ用、Ｇ用、Ｂ用のものを順番に並列配置している。
【００４５】
細管１ａは４００ｍｍの長さであり、この細管１ａ内に、実施形態１の電子放出膜の支持部材４と蛍光体層の支持部材５を配置する場合、２本の電子放出膜の支持部材４と２本の蛍光体層の支持部材５とを、細管１ａ内にそれぞれ直列に挿入する。蛍光体層の支持部材５は４００ｍｍの長さのものであってもよい。そして、電子放出膜の第１の支持部材４と第２の支持部材４との継ぎ目が、非放電領域２１に位置するように配置する。また、蛍光体層の第１の支持部材５と第２の支持部材５との継ぎ目も、非放電領域２１に位置するように配置することが望ましい。
【００４６】
図５は実施形態１における非放電領域の継ぎ目の状態を示す説明図である。
電子放出膜の第１の支持部材４と第２の支持部材４との継ぎ目は、非放電領域２１の位置で突き合わせにしているが、電子放出膜の支持部材４どうしを加熱溶融させて接着してもよいし、低融点ガラスのような接着剤を用いて接着してもよい。この接続は、支持部材４の内面にＭｇＯ膜を形成した後、その支持部材４を細管１ａ内に挿入する前に行う。２００ｍｍの蛍光体層の支持部材５を２本用いる場合も同様の方法で直列に接続してもよい。
【００４７】
細管１ａ内に、実施形態２の電子放出膜の支持部材６と蛍光体層の支持部材７を配置する場合も同様であり、２本の電子放出膜の支持部材６と２本の蛍光体層の支持部材７とを、細管１ａ内にそれぞれ直列に挿入する。この挿入に際しては、電子放出膜の支持部材６と蛍光体層の支持部材７が筒形となるように両者を向き合わせて、細管１ａの内部に挿入する。電子放出膜の支持部材６はボート形状であるので、４００ｍｍの長さのものであってもよい。蛍光体層の支持部材７も同様である。
【００４８】
そして、電子放出膜の第１の支持部材６と第２の支持部材６との継ぎ目が、非放電領域２１に位置するように配置する。また、蛍光体層の第１の支持部材７と第２の支持部材７との継ぎ目も、非放電領域２１に位置するように配置することが望ましい。
【００４９】
図６は実施形態２における非放電領域の継ぎ目の状態を示す説明図である。
電子放出膜の第１の支持部材６と第２の支持部材６との継ぎ目についても、非放電領域２１の位置で突き合わせにしているが、溶着、接着のいずれを用いてもよい。この接続も、支持部材６の凹部にＭｇＯ膜を形成した後、その支持部材６を細管１ａ内に挿入する前に行う。２００ｍｍの蛍光体層の支持部材７を２本用いる場合も同様の方法で直列に接続してもよい。
【００５０】
このようにして、細管１ａ内に、実施形態１の電子放出膜の支持部材４と蛍光体層の支持部材５、あるいは実施形態２の電子放出膜の支持部材６と蛍光体層の支持部材７を挿入し、固定を行うことで、細管１ａ内（放電空間内）に電子放出膜と蛍光体層を配置する。その後、細管１ａの内部の排気を行った後、細管１ａ内に放電ガスを封入し、細管１ａの両端を封止する。
【００５１】
この封止の際には、電子放出膜の支持部材と蛍光体層の支持部材を細管と共にチップオフして、細管の端部を封止することにより、電子放出膜の支持部材と蛍光体層の支持部材を細管内に固定することができる。
【００５２】
細管はガラス製であり、ガラス製の電子放出膜の支持部材および蛍光体層の支持部材となじみがよいため、封止の際に電子放出膜の支持部材と蛍光体層の支持部材を細管の端部と一緒に溶融して固定しても、細管のリーク等の発生が生じにくい。
【００５３】
このように、細管、電子放出膜の支持部材、蛍光体層の支持部材のアセンブリによって、ガス放電管を形成することにより、それぞれの工程で良品となったものを組み合わせて、１つのガス放電管とすることができるので、ガス放電管全体の歩留まりを向上させることができる。
【００５４】
図７は誘電体層の厚さを示す説明図である。ここでは実施形態２の例で説明する。図４で示した表示装置では、表示の際、表示電極対２間で面放電が発生される。このため、電極上の誘電体層、つまり細管１ａの厚さＨｔと電子放出膜の支持部材６の厚さＳｔとの合計の厚さが、表示電極対２間の放電開始電圧に影響を及ぼす。
【００５５】
図８は誘電体層の厚さ（μｍ）と放電開始電圧（Ｖ）との関係を示すグラフである。
誘電体層の厚さは、放電開始電圧を決めるパラメータの１つであり、細管１ａの内部に封入する放電ガスの組成や、圧力によっても放電開始電圧が変化する。このため、例えば、誘電体層が細管と電子放出膜の支持部材からなり、これらにホウケイ酸ガラスを用いた場合、表示電極対２間の面放電ギャップを２００μｍとし、封入する放電ガスをＮｅ（９６％）＋Ｘｅ（４％）とし、封入ガス圧を３５０Ｔｏｒｒとすると、誘電体層の厚さと放電開始電圧の関係は、このグラフに示すようになる。
【００５６】
グラフには示されていないが、たとえば誘電体層の厚さが３００μｍ以上になると、放電開始電圧は１０００Ｖを超えてしまい、電圧印加用のドライバのコストや、電子回路の耐圧を考慮すると実用的ではない。
【００５７】
したがって、放電開始電圧の制限からは、細管と電子放出膜の支持部材との合計の厚さ（Ｈｔ＋Ｓｔ）は、３００μｍ以下にすることが望ましい。また、細管１ａと電子放出膜の支持部材６との合計の厚さ（Ｈｔ＋Ｓｔ）は、機械的強度の面から、最低でも２０μｍ程度は必要である。したがって、細管１ａと電子放出膜の支持部材６との合計の厚さ（Ｈｔ＋Ｓｔ）は、２０〜３００μｍ程度の範囲とすることが望ましい。これは、実施形態１のガス放電管であっても同じである。
【００５８】
実施形態１と実施形態２のガス放電管では、細管と電子放出膜の支持部材との合計の厚さ（Ｈｔ＋Ｓｔ）は７０〜１２０μｍ程度であり、この厚さであれば、放電開始電圧は約４００〜５００Ｖとなり、実用的な放電開始電圧とすることができる。
【００５９】
このようにして、細管の外部で電子放出膜を支持部材に形成し、その支持部材を細管の内部に挿入して放電空間内に配置する。これにより、円筒状の支持部材を用いた場合には、支持部材の長さを短くして、電子放出膜形成用の塗布液を支持部材の内部に均一に塗布することができ、塗布膜の焼成時の酸素不足も解消することができる。また、ボート形状の支持部材を用いた場合には、電子放出膜形成用の塗布液を容易にかつ均一に塗布することができ、塗布膜の焼成時の酸素不足も解消することができる。しかも、電子放出膜を蒸着などの他の方法で形成することもできる。したがって、良好な電子放出膜を容易に形成することが可能となる。
【００６０】
【発明の効果】
本発明によれば、電子放出膜が細管と独立した支持部材に形成された構成であるので、ガス放細管の外部で電子放出膜を支持部材に形成し、その支持部材を細管の内部に挿入して放電空間内に配置することができる。したがって、電子放出膜形成用の塗布液を均一に塗布することが可能となる。また、その塗布膜の焼成が容易となる。これにより良好な電子放出膜を容易に形成することが可能となる。
【図面の簡単な説明】
【図１】本発明のガス放電管を用いた表示装置の一例を示す説明図である。
【図２】ガス放電管の実施形態１の構成を示す説明図である。
【図３】ガス放電管の実施形態２の構成を示す説明図である。
【図４】本発明のガス放電管を用いて表示装置を構成した例を示す説明図である。
【図５】実施形態１における非放電領域の継ぎ目の状態を示す説明図である。
【図６】実施形態２における非放電領域の継ぎ目の状態を示す説明図である。
【図７】誘電体層の厚さを示す説明図である。
【図８】誘電体層の厚さと放電開始電圧との関係を示すグラフである。
【符号の説明】
１ガス放電管
１ａ細管
２表示電極対
２ａバス電極
２ｂ透明電極
３信号電極
４，６電子放出膜の支持部材
４ａ，６ａ電子放出膜
５，７蛍光体層の支持部材
５ａ，７ａ蛍光体層
２１非放電領域
３１前面側の基板
３２背面側の基板[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gas discharge tube, and more particularly to a gas discharge tube using a thin tube having a diameter of about 0.5 to 5 mm.
[0002]
[Prior art]
There is known a display device that displays a desired image by arranging a plurality of gas discharge tubes in parallel. In the gas discharge tube of this display device, a thin tube having a diameter of about 0.5 to 5 mm is used.
[0003]
Conventionally, in a gas discharge tube using such a thin tube, an electron emission film having a function of generating charged particles on the inner surface of the thin tube due to collision with a discharge gas having an energy of a certain value or more and lowering a discharge start voltage, For example, when forming an MgO film, a solution of, for example, a fatty acid magnesium is applied to the inner surface of a thin tube by a spin coating method or the like, and the applied layer is baked.
[0004]
In this case, if the narrow tube is short (approximately 300 mm or less), the MgO film can be applied relatively uniformly on the inner surface of the narrow tube. Further, when firing the coating layer, if the inside diameter of the narrow tube is sufficiently large (4 mm or more), the resistance to air introduction into the narrow tube is low (the air conductance is high) and the firing is easy.
[0005]
[Problems to be solved by the invention]
However, when the length of the narrow tube exceeds 300 mm, it is difficult to uniformly apply the MgO film on the inner surface of the narrow tube by spin coating. When the inner diameter of the narrow tube is 2 mm or less, when firing the coating layer, oxygen necessary for burning the organic component of the fatty acid magnesium is insufficient inside the narrow tube, so that the organic component is not completely removed, and MgO The light transmittance of the film decreases.
[0006]
Accordingly, there has been a demand for the emergence of a technique capable of easily forming an electron emission film on the inner surface of a narrow tube even if the inner diameter is 2 mm or less or the length is 300 mm or more.
[0007]
The present invention has been made in consideration of such circumstances, and the electron emission film is formed on a support member separate from the thin tube, and the support member is disposed inside the thin tube, so that the electron emission film is formed. The purpose is to facilitate the formation.
[0008]
[Means for Solving the Problems]
The present invention provides a gas discharge tube having an electron emission film inside a narrow tube forming a discharge space, wherein a solution of fatty acid magnesium is applied to a support member independent of the thin tube and fired, whereby the electron emission film is formed. It is a gas discharge tube in which the support member is inserted into the thin tube and disposed in the discharge space after being formed in advance.
[0009]
According to the present invention, the electron emission film can be formed on the support member outside the narrow tube, and the support member can be inserted into the narrow tube and disposed in the discharge space. Therefore, for example, by forming the support member with a plurality of cylindrical members shorter than the thin tubes or with a semi-cylindrical member, the coating liquid for forming the electron emission film can be uniformly applied. . In addition, uneven baking due to lack of oxygen during firing of the coating film can be prevented. As a result, a good electron emission film can be easily formed.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
The gas discharge tube of the present invention may be formed using a thin tube having any diameter, but is preferably formed using a thin tube having a diameter of about 0.5 to 5 mm. The thin tube preferably has a circular cross section, but may have a flat elliptical cross section.
[0011]
In the present invention, for example, a discharge space is formed inside the narrow tube by sealing both ends of the thin tube, and an electron emission film is disposed in the discharge space. And in arrangement | positioning of the electron emission film | membrane, an electron emission film | membrane is formed in a support member independent of a thin tube, and the electron emission film | membrane is positioned in discharge space by inserting the support member in the inside of a thin tube.
[0012]
When the inner diameter of the capillary tube is small, the air permeability inside the capillary tube is poor, and even if an electron emission film is to be formed on the inner surface of the capillary tube, there is sufficient air when firing the coating film for forming the electron emission film applied to the inner surface of the capillary tube. Not supplied. Therefore, in the present invention, an electron emission film is formed on a support member that can be inserted into the inside of the narrow tube. That is, the electron emission film is not formed inside the narrow tube, but formed outside the narrow tube, and then introduced into the inside of the narrow tube.
[0013]
In the present invention, an electron emission film is formed on the support member. This electron emission film is made of MgO, CaO, SrO, BaO or the like.
The support member is not particularly limited as long as it is independent of the thin tube, but a plurality of tubular members shorter than the thin tube, or a half tube shape (hereinafter also referred to as a boat shape) obtained by dividing the tube in the longitudinal direction. It is desirable to use a member. The support member is preferably made of a dielectric material in order to generate discharge on the surface on which the electron emission film is formed.
[0014]
In the present invention, a phosphor layer formed on a support member independent of the thin tube may be further provided. In this case, if the support member for the electron emission film is cylindrical, the support member for the phosphor layer is provided. It is desirable to have a configuration in which the electron emission film is inserted into the support member and disposed in the discharge space.
[0015]
Further, if the electron emission film supporting member has a boat shape having a semicircular cross section obtained by dividing the cylinder in the longitudinal direction, and the phosphor layer supporting member has the same shape, each of the electron emitting film supporting films It is desirable that the support member and the support member of the phosphor layer are arranged so as to face each other so as to have a cylindrical shape, and are inserted into the narrow tube and disposed in the discharge space. In this case, the cross section of the support member of the electron emission film and the support member of the phosphor layer facing each other is a circle, and both of them have a half arc shape, but the invention is not limited to this. The shape may be large and the other arc may be small.
[0016]
As a material of the support member, it is desirable to use glass. When glass is used, if the thin tube is glass or the like, when the discharge gas is introduced into the thin tube and the end of the thin tube is sealed, the support member is melted together with the thin tube to chip off (melting) ), The support member can be fixed in the narrow tube. In this case, since the glass is compatible with each other, it is possible to prevent the occurrence of leakage of the narrow tube. Regarding the fixing of the support member in the narrow tube, it may be fixed using an adhesive such as low melting point glass.
[0017]
In the present invention, a plurality of the gas discharge tubes described above are arranged side by side on a support substrate, and a plurality of gas discharge tubes along the longitudinal direction thereof are in contact with the outer wall surface of the gas discharge tube on the gas discharge tube installation surface of the support substrate. And a display electrode pair in a direction crossing each gas discharge tube in contact with the outer wall surface on the surface side of the gas discharge tube.
[0018]
The present invention will be described in detail below based on the embodiments shown in the drawings. In addition, this invention is not limited by this, A various deformation | transformation is possible.
The gas discharge tube of the present invention is suitably used for a display device in which a plurality of gas discharge tubes are arranged in parallel to display an arbitrary image. An example of this display device will be described.
[0019]
FIG. 1 is an explanatory view showing an example of a display device using the gas discharge tube of the present invention.
In the figure, 31 is a front substrate, 32 is a rear substrate, 1 is a gas discharge tube, 2 is a display electrode pair (main electrode pair), and 3 is a signal electrode (also referred to as a data electrode).
[0020]
Inside the tubular gas discharge tube 1 (discharge space), a support member having an electron emission film (hereinafter referred to as a support member for the electron emission film) and a support member having a phosphor layer (hereinafter referred to as a phosphor layer). Are inserted and disposed, discharge gas is introduced, and both ends are sealed. The signal electrode 3 is formed on the substrate 32 on the back side, and is provided along the longitudinal direction of the gas discharge tube 1. The display electrode pair 2 is formed on the front substrate 31 and is provided in a direction crossing the signal electrode 3. A non-discharge region (non-discharge gap) 21 is provided between the display electrode pair 2 and the display electrode pair 2.
[0021]
The signal electrode 3 and the display electrode pair 2 are brought into contact with the lower outer peripheral surface and the upper outer peripheral surface of the gas discharge tube 1 during assembly, respectively, but in order to improve the adhesion, the display electrode and the gas You may adhere | attach by interposing an adhesive agent between discharge tube surfaces.
[0022]
When this display device is viewed in plan, the intersection of the signal electrode 3 and the display electrode pair 2 is a unit light emitting region. In the display, any one of the display electrode pairs 2 is used as a scanning electrode, a selective discharge is generated at the intersection of the scanning electrode and the signal electrode 3, and a light emitting region is selected. This is performed by generating a display discharge at the display electrode pair 2 using the wall charges formed on the inner surface of the tube. The selective discharge is a counter discharge generated in the gas discharge tube 1 between the scanning electrode and the signal electrode 3 facing each other in the vertical direction, and the display discharge is two display electrodes arranged in parallel on a plane. It is a surface discharge generated in the gas discharge tube 1 in between.
[0023]
The electrode structure shown in the figure has a structure in which three electrodes are arranged in one light emitting portion and a display discharge is generated by a display electrode pair. However, the present invention is not limited to this, and the display electrode 2, the signal electrode 3, The display discharge may be generated between the two.
[0024]
That is, an electrode structure in which the display electrode pair 2 is one and the selective discharge and the display discharge (opposite discharge) are generated between the display electrode 2 and the signal electrode 3 using the display electrode 2 may be used.
[0025]
FIG. 2 is an explanatory diagram showing the configuration of the first embodiment of the gas discharge tube. The figure shows a cross section perpendicular to the longitudinal direction of the gas discharge tube. In the figure, 1a is a thin tube serving as a gas discharge tube, 4 is a support member for the electron emission film, and 5 is a support member for the phosphor layer.
[0026]
In this embodiment, the thin tube 1a has a circular cross section, is made of borosilicate glass, and has a tube outer diameter of 1000 μm, a wall thickness of 60 μm, and a length of 400 mm. A support member 4 for the electron emission film is disposed inside the narrow tube 1a, and a support member 5 for the phosphor layer is disposed inside the support member 4 for the electron emission film. The support member 4 for the electron emission film and the support member 5 for the phosphor layer are also made of borosilicate glass.
[0027]
The thin tube 1a is produced by producing a large base material similar to the thin tube 1a by the Danner method and redrawing (stretching) while heating and softening it. The support member 4 for the electron emission film and the support member 5 for the phosphor layer are produced in the same manner. In addition, these may not be redraw but the final shape may be directly formed by a hot press.
[0028]
The electron emission film support member 4 has a circular cross section that is slightly smaller than the narrow tube 1a, and is manufactured with an outer diameter of the tube of 860 μm, a thickness of 60 μm, and a length of 200 mm. On the inner surface of the electron emission film support member 4, an MgO film 4a as an electron emission film is formed to a thickness of 0.1 to 1 μm. The MgO film 4a is formed on the inner surface of the support member 4 before the support member 4 of the electron emission film is inserted into the thin tube 1a.
[0029]
The MgO film 4a is formed by applying a solution of fatty acid magnesium on the inner surface of the support member 4 by spin coating and drying, and then baking the applied layer.
[0030]
Since the support member 4 of the electron emission film has a length of 200 mm, the fatty acid magnesium solution can be uniformly applied to the inner surface of the support member 4. Also, with this length, oxygen required for the combustion of the organic component of fatty acid magnesium is not deficient in the support member 4 during firing, so that the light transmittance is reduced in the fired MgO film. Absent. Thereby, a good MgO film can be uniformly formed on the inner surface of the support member 4.
[0031]
The support member 5 for the phosphor layer has a boat shape obtained by dividing a cylinder having an outer diameter of 720 μm into two in the longitudinal direction, has a semicircular cross section, and is manufactured with a thickness of 60 μm and a length of 200 mm. In the concave portion of the support member 5 of the phosphor layer, the phosphor layer 5a is formed with a thickness of 20 to 30 μm. The phosphor layer 5a is formed in the recess of the support member 5 before the support member 5 of the phosphor layer is inserted into the support member 4 of the electron emission film.
[0032]
The phosphor layer 5a is formed of any one of phosphors of R (red), G (green), and B (blue) necessary for full color display. The phosphor layer 5a is formed by using a phosphor known in the art, applying a paste containing the phosphor to the concave portion of the support member 5, drying it, and baking it.
[0033]
Since the phosphor layer 5a is formed outside the thin tube 1a and the support member 5 for the electron emission film, even if the paste containing the phosphor is applied to the concave portion of the support member 5 and then baked, oxygen may be deficient. The organic component can be completely burned out.
[0034]
In this gas discharge tube, since the structure is a double structure of the thin tube 1a and the electron emission film support member 4, the total thickness of the thin tube and the electron emission film support member is set to a small tube in the case of a single structure. The thickness should be the same as the wall thickness.
[0035]
FIG. 3 is an explanatory diagram showing the configuration of the second embodiment of the gas discharge tube. The figure shows a cross section perpendicular to the longitudinal direction of the gas discharge tube. In the figure, 6 is a support member for the electron emission film, and 7 is a support member for the phosphor layer.
[0036]
In this embodiment, the thin tube 1a is the same as that in the first embodiment. Inside the narrow tube 1a, an electron emission film support member 6 and a phosphor layer support member 7 are arranged. The support member 6 for the electron emission film and the support member 7 for the phosphor layer are also made of borosilicate glass by redrawing.
[0037]
The electron emission film support member 6 has a boat shape in which a cylinder having an outer diameter of 860 μm is divided into two in the longitudinal direction, and is manufactured with a thickness of 60 μm and a length of 200 mm. An MgO film 6a as an electron emission film is formed in a thickness of 0.1 to 1 μm in the recess of the electron emission film support member 6. The MgO film 6a is formed in the concave portion of the support member 6 before the support member 6 of the electron emission film is inserted into the thin tube 1a.
[0038]
The MgO film 6a is formed by applying a solution of a fatty acid magnesium to the recesses of the support member 6 by a slot coat method, a spin coat method, or the like and then drying the applied layer.
[0039]
Since the support member 6 of the electron emission film has a boat shape, even when the support member has a length exceeding 300 mm, the fatty acid magnesium solution can be uniformly applied. In addition, since there is no oxygen deficiency during firing of the fatty acid magnesium coating layer, the light transmittance does not decrease in the fired MgO film. Thereby, a good MgO film can be uniformly formed in the recesses of the support member 6.
[0040]
Further, since the electron emission film support member 6 has a boat shape, the MgO film is not formed by a thermal decomposition method using a coating solution such as a fatty acid magnesium solution, but by an evaporation method or the like. be able to.
[0041]
The support member 7 of the phosphor layer has the same shape as the support member 6 of the electron emission film, and the phosphor layer 7a is formed in the concave portion of the support member 7 of the phosphor layer in the same manner as in the first embodiment by 20 to 30 μm. The thickness is formed. The phosphor layer 7a is formed in the recess of the support member 7 before the support member 7 of the phosphor layer is inserted into the thin tube 1a.
[0042]
Also in this embodiment, since the phosphor layer 7a is formed outside the thin tube 1a, even if the paste containing the phosphor is applied to the concave portion of the support member 7 and then baked, the organic component does not become deficient in oxygen. Can be burnt down completely.
[0043]
Also in this gas discharge tube, the structure is a double structure of the tube structure formed by the thin tube 1a, the electron emission film support member 6 and the phosphor layer support member 7, so that the thin tube and the electron emission film The total wall thickness with the support member needs to be the same as the wall thickness of the thin tube in the case of a single structure.
[0044]
FIG. 4 is an explanatory diagram showing an example in which a display device is configured using the gas discharge tube described above. This figure shows a state in which the display device shown in FIG.
In this example, the display electrode pair 2 includes a transparent electrode 2a and a bus electrode 2b, respectively. Signal electrodes are not shown. The thin tubes 1a are arranged in parallel in order for R, G, and B.
[0045]
The thin tube 1a has a length of 400 mm. When the electron emission film support member 4 and the phosphor layer support member 5 of the first embodiment are arranged in the thin tube 1a, the two electron emission film support members 4 are arranged. And two phosphor layer support members 5 are respectively inserted in series in the thin tube 1a. The phosphor layer support member 5 may have a length of 400 mm. Then, the joint between the first support member 4 and the second support member 4 of the electron emission film is disposed so as to be located in the non-discharge region 21. In addition, it is desirable that the joint between the first support member 5 and the second support member 5 of the phosphor layer is also located in the non-discharge region 21.
[0046]
FIG. 5 is an explanatory diagram showing a state of a joint of the non-discharge region in the first embodiment.
The joint between the first support member 4 and the second support member 4 of the electron emission film is abutted at the position of the non-discharge region 21, but the support members 4 of the electron emission film are heated and melted to be bonded. Alternatively, it may be bonded using an adhesive such as low melting point glass. This connection is performed after the MgO film is formed on the inner surface of the support member 4 and before the support member 4 is inserted into the narrow tube 1a. When two 200 mm phosphor layer support members 5 are used, they may be connected in series by the same method.
[0047]
The same applies to the case where the electron emission film support member 6 and the phosphor layer support member 7 of the second embodiment are arranged in the thin tube 1a, and the two electron emission film support members 6 and the two phosphor layers are the same. The support members 7 are inserted in series into the thin tube 1a. In this insertion, the electron emission film support member 6 and the phosphor layer support member 7 face each other so as to form a cylindrical shape, and are inserted into the thin tube 1a. Since the electron emission film support member 6 has a boat shape, it may have a length of 400 mm. The same applies to the support member 7 of the phosphor layer.
[0048]
Then, the seam between the first support member 6 and the second support member 6 of the electron emission film is disposed so as to be located in the non-discharge region 21. In addition, it is desirable that the joint between the first support member 7 and the second support member 7 of the phosphor layer is also located in the non-discharge region 21.
[0049]
FIG. 6 is an explanatory view showing a state of a joint of a non-discharge region in the second embodiment.
The seam between the first support member 6 and the second support member 6 of the electron emission film is also abutted at the position of the non-discharge region 21, but either welding or adhesion may be used. This connection is also made after the MgO film is formed in the recess of the support member 6 and before the support member 6 is inserted into the narrow tube 1a. Even when two 200 mm phosphor layer support members 7 are used, they may be connected in series by the same method.
[0050]
In this manner, the electron emission film support member 4 and the phosphor layer support member 5 of the first embodiment, or the electron emission film support member 6 and the phosphor layer support member 7 of the second embodiment are disposed in the narrow tube 1a. By inserting and fixing, the electron emission film and the phosphor layer are arranged in the narrow tube 1a (in the discharge space). Then, after exhausting the inside of the thin tube 1a, discharge gas is enclosed in the thin tube 1a, and both ends of the thin tube 1a are sealed.
[0051]
At the time of sealing, the support member for the electron emission film and the support member for the phosphor layer are chipped off together with the thin tube, and the end portion of the thin tube is sealed, whereby the support member for the electron emission film and the phosphor layer are sealed. The supporting member can be fixed in the narrow tube.
[0052]
Since the thin tube is made of glass and is familiar with the glass electron emission film support member and the phosphor layer support member, the electron emission film support member and the phosphor layer support member are connected to the capillary tube during sealing. Even if it is melted and fixed together with the end portion, the occurrence of leaking of the narrow tube is difficult to occur.
[0053]
Thus, a gas discharge tube is formed by an assembly of a thin tube, a support member for an electron emission film, and a support member for a phosphor layer. Therefore, the yield of the entire gas discharge tube can be improved.
[0054]
FIG. 7 is an explanatory view showing the thickness of the dielectric layer. Here, an example of the second embodiment will be described. In the display device shown in FIG. 4, surface discharge is generated between the display electrode pair 2 during display. Therefore, the total thickness of the dielectric layer on the electrode, that is, the thickness Ht of the thin tube 1a and the thickness St of the electron emission film support member 6 affects the discharge start voltage between the display electrode pair 2. .
[0055]
FIG. 8 is a graph showing the relationship between the thickness (μm) of the dielectric layer and the discharge start voltage (V).
The thickness of the dielectric layer is one of the parameters that determine the discharge start voltage, and the discharge start voltage varies depending on the composition and pressure of the discharge gas sealed in the thin tube 1a. For this reason, for example, when the dielectric layer is composed of a support member of a thin tube and an electron emission film, and borosilicate glass is used for these, the surface discharge gap between the display electrode pair 2 is 200 μm, and the discharge gas to be sealed is Ne ( 96%) + Xe (4%) and the sealed gas pressure is 350 Torr, the relationship between the thickness of the dielectric layer and the discharge start voltage is as shown in this graph.
[0056]
Although not shown in the graph, for example, when the thickness of the dielectric layer is 300 μm or more, the discharge start voltage exceeds 1000 V, which is practical in consideration of the cost of the voltage application driver and the withstand voltage of the electronic circuit. is not.
[0057]
Therefore, it is desirable that the total thickness (Ht + St) of the thin tube and the support member for the electron emission film be 300 μm or less from the limitation of the discharge start voltage. The total thickness (Ht + St) of the thin tube 1a and the electron emission film support member 6 is required to be at least about 20 μm from the viewpoint of mechanical strength. Therefore, the total thickness (Ht + St) of the thin tube 1a and the electron emission film support member 6 is preferably in the range of about 20 to 300 μm. The same applies to the gas discharge tube of the first embodiment.
[0058]
In the gas discharge tubes of Embodiments 1 and 2, the total thickness (Ht + St) of the thin tube and the support member of the electron emission film is about 70 to 120 μm. With this thickness, the discharge start voltage is about It becomes 400-500V, and it can be set as a practical discharge start voltage.
[0059]
In this manner, the electron emission film is formed on the support member outside the narrow tube, and the support member is inserted into the narrow tube and disposed in the discharge space. As a result, when a cylindrical support member is used, the length of the support member can be shortened so that the coating solution for forming the electron emission film can be uniformly applied to the inside of the support member. Insufficient oxygen during firing can also be eliminated. In addition, when a boat-shaped support member is used, a coating solution for forming an electron emission film can be easily and uniformly applied, and oxygen shortage during firing of the coating film can be eliminated. Moreover, the electron emission film can be formed by other methods such as vapor deposition. Therefore, a good electron emission film can be easily formed.
[0060]
【The invention's effect】
According to the present invention, since the electron emission film is formed on the support member independent of the capillary tube, the electron emission film is formed on the support member outside the gas discharge tube, and the support member is inserted into the capillary tube. And can be arranged in the discharge space. Therefore, it becomes possible to apply | coat the coating liquid for electron emission film formation uniformly. Moreover, the coating film can be easily baked. As a result, a good electron emission film can be easily formed.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing an example of a display device using a gas discharge tube of the present invention.
FIG. 2 is an explanatory diagram showing a configuration of a first embodiment of a gas discharge tube.
FIG. 3 is an explanatory diagram showing a configuration of a gas discharge tube according to a second embodiment.
FIG. 4 is an explanatory diagram showing an example in which a display device is configured using the gas discharge tube of the present invention.
FIG. 5 is an explanatory diagram showing a state of a seam of a non-discharge region in the first embodiment.
FIG. 6 is an explanatory diagram showing a state of a seam in a non-discharge region in the second embodiment.
FIG. 7 is an explanatory diagram showing the thickness of a dielectric layer.
FIG. 8 is a graph showing the relationship between the thickness of the dielectric layer and the discharge start voltage.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Gas discharge tube 1a Narrow tube 2 Display electrode pair 2a Bus electrode 2b Transparent electrode 3 Signal electrode 4, 6 Electron emission film support member 4a, 6a Electron emission film 5, 7 Phosphor layer support member 5a, 7a Phosphor layer 21 Non-discharge region 31 Front side substrate 32 Back side substrate

Claims

In a gas discharge tube having an electron emission film inside a narrow tube forming a discharge space, an electron emission film is formed in advance by applying a solution of fatty acid magnesium to a support member independent of the thin tube and firing it. And a gas discharge tube in which the support member is inserted into the thin tube and disposed in the discharge space.

The gas discharge tube according to claim 1, wherein the support member is composed of a plurality of cylindrical members shorter than the thin tube.

A phosphor layer formed on a support member independent of the narrow tube is further provided, and the support member of the phosphor layer is inserted into the cylindrical support member of the electron emission film and disposed in the discharge space. Item 3. A gas discharge tube according to Item 2.

The gas discharge tube according to claim 1, wherein the support member is formed of a semi-cylindrical member obtained by dividing the cylinder in the longitudinal direction.

A phosphor layer formed on a support member independent of the thin tube is further provided, and the support member of the phosphor layer is formed of a semi-cylindrical member obtained by dividing a cylinder in the longitudinal direction. The gas discharge tube according to claim 4, wherein the support member and the support member of the phosphor layer face each other so as to have a cylindrical shape, are inserted into the narrow tube, and are disposed in the discharge space.

The gas discharge tube according to claim 1, 2 or 4, wherein the total thickness of the thin tube and the support member is 20 to 300 µm.

A plurality of gas discharge tubes according to any one of claims 1 to 6 are arranged side by side on a support substrate, and the gas discharge tube installation surface of the support substrate is in contact with the outer wall surface of the gas discharge tube. A display device in which a plurality of signal electrodes are formed along a longitudinal direction, and a display electrode pair is provided in a direction crossing each gas discharge tube in contact with an outer wall surface on the surface side of the gas discharge tube.