JP3646675B2 - Afterglow phosphor - Google Patents

Description

ただし、組成式中のＭはＭｇ、Ｃａ、Ｓｒ、Ｂａ、及びＺｎからなる２価金属の群より選ばれた少なくとも１種であり、Ｑは共付活剤でありＭｎ、Ｚｒ、Ｎｂ、Ｐｒ、Ｎｄ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｙｂ、及びＬｕからなる群より選ばれた少なくとも１種である。
【００１３】
上記した組成をさらに以下の特定範囲に調整することで、蛍光色及び残光色を選択することができる。
【００１４】
発光ピーク波長が５２０ｎｍ付近の緑色発光の残光性蛍光体を調製する場合、次のような組成範囲に選択する。すなわち、２価のユーロピウムで付活されたアルミン酸塩蛍光体において、その化学組成式が下記の範囲にある結晶構造が単斜晶系を主体とする残光性蛍光体とする。

ただし、組成式中のＭはＳｒが７０モル％以上である。
【００１５】
発光ピーク波長が４４０ｎｍ付近の青色発光の残光性蛍光体を調製する場合、次のような組成範囲に選択する。すなわち、２価のユーロピウムで付活されたアルミン酸塩蛍光体において、その化学組成式が下記の範囲にあり、結晶構造が単斜晶系を主体とすることを特徴とする残光性蛍光体とする。

ただし、組成式中のＭはＣａが７０モル％以上である。
【００１６】
発光ピーク波長が４９０ｎｍ付近の青緑色発光の残光性蛍光体を調製する場合、次のような組成範囲に選択する。すなわち、２価のユーロピウムで付活されたアルミン酸塩蛍光体において、その化学組成式が下記の範囲にあり、結晶構造が斜方晶系を主体とすることを特徴とする残光性蛍光体とする。

ただし、組成式中のＭはＳｒが７０モル％以上である。
【００１７】
発光ピーク波長が４９０ｎｍ付近の青緑色発光の残光性蛍光体は、特に、次のような組成範囲に選択することが発光輝度、残光輝度の点で好ましい。すなわち、２価のユーロピウムで付活されたアルミン酸塩蛍光体において、その化学組成式が下記の範囲にあり、結晶構造が斜方晶系を主体とすることを特徴とする残光性蛍光体とする。

ただし、組成式中のＭはＳｒである。
【００１８】
本発明の残光性蛍光体に導入する付活剤および共付活剤は、蛍光色および残光輝度に大きく影響する。実用上、それぞれ次に示すような範囲に調整する。
【００１９】
付活剤のＥｕの濃度ｐについては、蛍光体１モルに対し、母体のＳｒを０．０００１モル以上、０．５モル以下置換する範囲に調整する。なぜなら０．０００１モルより少ないと光吸収が悪くなり、その結果残光輝度が低くなり、逆に、０．５モルよりも多くなると、濃度消光を起こし残光輝度が低下するからだ。ｐのさらに好ましい範囲は０．００１≦ｐ≦０．０６のであり、この範囲で残光輝度がさらに高くなる。
【００２０】
共付活剤を導入することによりＥｕの発光は残光性を示すようになる。共付活剤としてＭｎ、Ｚｒ、Ｎｂ、Ｐｒ、Ｎｄ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｙｂ、及びＬｕからなる群より選ばれた少くとも一種が有効である。
【００２１】
Ｄｙは蛍光体母体の２価金属Ｍが特にＳｒの場合に残光性向上に効果的であり、Ｄｙ濃度ｑの最適濃度範囲は０．０００５以上、０．０３以下の範囲である。
【００２２】
Ｎｄは蛍光体母体の２価金属Ｍが特にＣａの場合に残光輝度向上に特に効果があり、Ｎｄ濃度ｑの最適範囲は０．０００５以上、０．０３以下の範囲である。
【００２３】
これら共付活剤Ｄｙ、Ｎｄに、他の第２に共付活剤を付活することにより相乗効果を発揮する。
【００２４】
第一の共付活剤としてＤｙを選択する場合、第２の共付活剤のＭｎ濃度ｑの好ましい範囲は０．０００１以上、０．０６以下で、更に好ましいのは０．０００５以上、０．０２以下の範囲である。
【００２５】
第一の共付活剤としてＤｙを選択する場合、第２の共付活剤のＴｍ濃度ｑの好ましい範囲は０．０００３以上、０．０２以下で、更に好ましいのは０．０００４以上、０．０１以下の範囲である。
【００２６】
第一の共付活剤としてＤｙを選択する場合、第２の共付活剤のＬｕ濃度ｑの好ましい範囲は０．０００１以上、０．０６以下で、更に好ましいのは０．０００４以上、０．０４以下の範囲である。
【００２７】
第一の共付活剤としてＤｙを選択する場合、第２の共付活剤のＮｂ濃度ｑの好ましい範囲は０．０００１以上、０．０８以下で、更に好ましいのは０．０００３以上、０．０４以下の範囲である。
【００２８】
第一の共付活剤としてＤｙを選択する場合、第２の共付活剤のＹｂ濃度ｑの好ましい範囲は０．０００２以上、０．０４以下で、更に好ましいのは０．０００３以上、０．０１以下の範囲である。
【００２９】
第一の共付活剤としてＤｙを選択する場合、第２の共付活剤のＺｒ濃度ｑの好ましい範囲は０．００２以上、０．７０以下である。
【００３０】
第一の共付活剤としてＤｙを選択する場合、第二の共付活剤のＥｒ濃度ｑの好ましい範囲は０．０００１以上、０．０３以下である。更に好ましいのは０．０００５以上、０．０２以下の範囲である。
【００３１】
第一の共付活剤としてＤｙを選択する場合、第２の共付活剤のＰｒ濃度ｑの好ましい範囲は０．０００１以上、０．０４以下である。更に好ましいのは０．０００５以上、０．０３以下の範囲である。
【００３２】
第一の共付活剤としてＮｄを導入する場合、第２の共付活剤のＴｍ濃度ｑの好ましい範囲は０．０００１以上、０．０６以下で、更に好ましいのは０．０００５以上、０．０２以下の範囲である。
【００３３】
第一の共付活剤としてＮｄを導入する場合、第２の共付活剤のＰｒ濃度ｑの好ましい範囲は０．０００１以上、０．０６以下で、更に好ましいのは０．０００５以上、０．０２以下の範囲である。
【００３４】
第一の共付活剤としてＮｄを以下導入する場合、第２の共付活剤のＨｏ濃度ｑの好ましい範囲は０．０００１以上、０．０６以下で、更に好ましいのは０．０００５以上、０．０２以下の範囲である。
【００３５】
第一の共付活剤としてＮｄを以下導入する場合、第２の共付活剤のＤｙ濃度ｑの好ましい範囲は０．０００１以上、０．０６以下で、更に好ましいのは０．０００５以上、０．０２以下の範囲である。
【００３６】
本発明の残光性蛍光体の母体組成については、アルミニウムの一部をホウ素で置換することにより、残光特性はさらに大きく改善される。ホウ素はアルミニウムの総モル数の０．０００１モルから０．５モル置換する範囲が適当であり、より好ましくは、０．００５モルから０．２５モルになる範囲であり、最も好ましいのは、０．０５モル付近である。ホウ素を導入するには、アルミニウムをそれに見合う量だけ差し引いて仕込むことが好ましい。
【００３７】
リン酸化合物濃度ｋは０．００１以上、０．２以下の範囲が好ましく、０．０１以上、０．１以下の範囲がさらに好ましく、０．０３以上、０．０５以下の範囲が最も好ましい。
【００３８】
本発明の残光性蛍光体は、原料として例えばＳｒＯ、ＭｇＯ、Ａｌ_２Ｏ_３、Ｅｕ_２Ｏ_３のような金属酸化物、或いはＣａＣＯ_３、ＳｒＣＯ_３、ＢａＣＯ_３のような高温で焼成することで容易に酸化物になるような化合物を選択する。このような化合物として炭酸塩の他には硝酸塩、シュウ酸塩、水酸化物などがある。また、ホウ素化合物としてはホウ酸あるいはアルカリ土類のホウ酸塩が使用でき、特に、ホウ酸が好ましい。また、本残光性蛍光体の組成にリン酸を導入させるには、リン酸、無水リン酸、リン酸アンモニウム、アルカリ土類元素のリン酸塩等が好ましく使用できる。
【００３９】
原料の純度は残光輝度に大きく影響し、９９．９％以上であることが好ましく、９９．９９％以上であることがさらに好ましい。これらのフラックスを混合した原料を、還元雰囲気下１２００℃以上１６００℃以下の温度で焼成し、焼成品を粉砕、篩することで本発明の残光性蛍光体が得られる。尚、原料の混合比率は、目的の組成を得る為の理論量を混合することで決定できる。
【００４０】
これらを混合した原料を、還元雰囲気下１２００℃以上１６００℃以下の温度範囲で焼成し、焼成品を粉砕、篩することで本発明の残光性蛍光体が得られる。尚、原料の混合比率は、目的の組成を得る為の理論量を混合することで決定できる。
【００４１】
【作用】
本発明の残光性蛍光体は基本的に付活剤の２価のＥｕによる強い発光を呈するが、２価のＥｕは可視光から紫外域の広範囲に吸収があり、従って、自然光のような広範囲な波長域で励起され高効率の発光（蛍光）を示す。また、共付活剤として、Ｍｎ、Ｚｒ、Ｎｂ、Ｐｒ、Ｎｄ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｙｂ、及びＬｕからなる群より選ばれた少なくとも１種を蛍光体母体にドープさせることで残光現象が現れる。
【００４２】
本発明の残光性蛍光体においてはホウ素を含有することで、アルミネートの結晶性を良好にし、発光中心と捕獲中心を安定化させることで残光時間、残光輝度の改善に有効に働いていると推定できる。また、ホウ素は同時にフラックスとして働き蛍光体の結晶成長を促進し、りん光輝度が大幅に改善できる。
【００４３】
２価金属、付活剤、共付活剤の酸化物の総モル数とアルミナ及びホウ酸の総モル数がほぼ１：１すなわちｎ＝１である場合、Ｘ線回折により解析した結果、結晶構造はＳｒＡｌ_２Ｏ_４型の単斜晶系となり、波長５２０ｎｍにピークのある緑色発光を示す。
【００４４】
しかしながら、この残光性蛍光体は耐熱性が悪く、しかもこの硼酸の添加とともに耐熱性はさらに悪くなり、しかも焼成品は固くなり、後工程での粉砕及び篩等の処理が困難となる。これに対し、組成原料として、リン酸化合物を加えて焼成することで、耐熱性、耐水性が向上する。
【００４５】
加えたホウ酸の大半がアルミナと混晶をつくり蛍光体組成に組み込まれるが、一部の過剰となったホウ酸は、リン酸化合物及び２価金属と混晶をつくり蛍光体粒子間の溶融反応を防ぐ働きがあると考えられ、そのことが耐熱性向上に寄与している。また、この混晶は水に不溶性で残光性蛍光体の粒子表面を被覆するため、残光性蛍光体に耐水性を付与する。
【００４６】
残光性蛍光体の焼成時にリン酸化合物を添加して焼成すると、大半はリン酸化合物としてその組成中に含有される。その含有量とりん光輝度、耐熱性、耐水性への影響をみるため、(Sr_{０．９５５}Eu_０．０３Dy_{０．０１５})O・0.91(Al_０．９５B_０．０５)_２O_３・kP_２O_５残光性蛍光体を試作し、リン酸化合物の含有量ｋに対するそれぞれの特性を評価した。ここで耐熱性、耐水性については次のような方法で行った。
【００４７】
耐熱性については、石英ルツボに残光性蛍光体を１０ｇ入れ、マッフル炉中６００℃で３０分間酸化焼成を行い、焼成品のりん光輝度を測定し、焼成前の残光性蛍光体のりん光輝度対する百分率を算出し維持率として求める。
【００４８】
耐水性については、２５０ｍｌのプラスチック容器に残光性蛍光体を１０ｇ、純水を２００ｇ入れ、ローラーで３０ｒｐｍの速度で７２時間回転させる。次に固液分離し乾燥し、残光性蛍光体のりん光輝度を測定し、水に接触させる前のりん光輝度対する百分率を算出し維持率として求める。
【００４９】
これらの測定結果をもとに図１〜３に、それぞれりん光輝度、耐熱性、耐水性のリン酸含有量ｋとの関係を示す。図１から分かるようにリン酸の含有がｋ≦０．１の広い範囲で励起停止２０分後りん光輝度向上に効果があり、ｋ＝０．０５付近が最も高くなる。ｋ＞０．１の範囲ではりん光輝度はリン酸化合物を含有しないものよりも低くなる。
【００５０】
図２に示す耐熱試験の結果より、リン酸化合物の含有は広い濃度範囲で耐熱性に効果があることが分かり、ｋ≧０．００００５で耐熱性に効果があり、特にｋ≧０．０１が好ましく、０．０２≦ｋ≦０．０５の範囲が最も好ましい。
【００５１】
リン酸化合物を含まない残光性蛍光体の耐水性は何れも０％であって、これは蛍光体結晶が破壊されてしまい、全く光らなくなってしまうことによる。図３に示すように、耐水性に及ぼすリン酸の効果は広い範囲に渡り、実際０＜ｋであれば効果があるが、０．００１≦ｋ≦０．６の範囲で維持率が２０％を越え、０．０２≦ｋ≦０．１の範囲で維持率が４０％を越え、ｋ＝０．０５付近が特に維持率が５０％を越えて最も好ましい。
【００５２】
これらを総合して判断すると、リン酸化合物濃度ｋは０．００１≦ｋ≦０．２の範囲が好ましく、０．０１≦ｋ≦０．１の範囲がさらに好ましく、０．０３≦ｋ≦０．０５の範囲が最も好ましいといえる。しかし、どのような環境で使用するかにより、ｋの値を選択すべきである。
【００５３】
２価金属ＭがＳｒである場合の蛍光体結晶構造をＸ線回折により解析した結果、リン酸化合物を含有しない残光性蛍光体の結晶はＳｒＡｌ_２Ｏ_４の単斜晶系の構造を示すが、硼酸と同時に少しでもリン酸を含有すると、α−Ｓｒ_３Ｐ_２Ｏ_８の異種の型の結晶が混在してくるようになる。さらにリン酸が増えｎ／４≦ｋとなると、完全にα−Ｓｒ_３Ｐ_２Ｏ_５だけの結晶になる。また、２価金属ＭがＣａである場合、リン酸化合物を含有しない残光性蛍光体の結晶はＣａＡｌ_２Ｏ_４の単斜晶系構造を示すが、少しでもリン酸を含有すると、ＣａＰ_２Ｏ_６の異種の型の結晶が混在するようになる。
【００５４】
【実施例】
［実施例１］
蛍光体原料として、ＳｒＣＯ_３を１４０．９８ｇ（０．９５５ｍｏｌ）、Ａｌ_２Ｏ_３を８８．１４ｇ（０．８６５ｍｏｌ）、Ｅｕ_２Ｏ_３を５．２８ｇ（０．０１５ｍｏｌ）、Ｄｙ_２０_３を２．８０ｇ（０．００７５ｍｏｌ）、Ｈ_３ＢＯ_３を５．６３ｇ（０．０９１ｍｏｌ）、及び（ＮＨ_４）_２ＨＰＯ_４を７．９２ｇ（０．０６０ｍｏｌ）を、混合媒体としてアルミナボール入りのセラミックポットに入れ、ローラーで２時間混合し蛍光体焼成前混合原料（以下原料生粉という）を得る。次に、原料生粉をアルミナルツボに入れ、還元雰囲気下１４００℃で５時間焼成し蛍光体焼成品を得る。次に焼成品を粉砕し、２００メッシュの篩を通し、本発明の(Sr_{０．９５５}Eu_０．０３Dy_{０．０１５})O・0.91(Al_０．９５B_０．０５)_２O_３・0.03P_２O_５蛍光体を得る。
【００５５】
得られた蛍光体は可視から紫外域の広い範囲において励起発光し、ブラックライト、殺菌灯によっても励起され発光し、よって、蛍光水銀灯、低圧水銀蒸気放電灯にも応用できるが、ここでは、蓄光蛍光体の用途に応じた試験をJIS K 5120に従い行う。
【００５６】
蛍光体試料１ｇにアクリル樹脂ワニスを０．５ｇ加え、試料をすりつぶさないように注意して十分練り合わせ、アルミニウム板に試料が１００mg/cm^２以上の厚さになるように塗り、乾燥したものを試験片とした。この試験片は、蛍光色、りん光輝度、及び耐光性の測定に用いる。
【００５７】
蛍光色の測定については、２５３．７ｎｍの紫外線を試料に当て、蛍光を分光光度計によりスペクトル分布を求め、ＣＩＥ表色系の色度を算出した。蛍光色度はｘ＝０．２４８，ｙ＝０．５６１で、視感度の高い緑色系を呈し、蓄光蛍光体として優れた基本特性を有することが明らかである。
【００５８】
りん光輝度の測定については、JIS Z 9100（蓄光安全標識板のりん光輝度の測定方法）を参考に行った。試験片を暗所に３時間以上外光を遮断した状態で保管した後、試験片に常用光源Ｄ_６５の光を２００ルクスの照度で４分間照射し、照射を止めてから２０分後のりん光輝度を(Sr_{０．９５５}Eu_０．０３Dy_{０．０１５}Tm_{０．００３})O・(Al_０．９５B_０．０５)_２O_３蛍光体のりん光輝度を１００％とした相対値として測定した。本発明の残光性蛍光体(Sr_{０．９５２}Eu_０．０３Dy_{０．０１５})O・0.91(Al_０．９５B_０．０５)_２O_３・0.03P_２O_５のりん光輝度は９８％であった。
【００５９】
耐光性の試験については、JIS K 5671中の発光塗料の耐光性の試験方法を参考に次のように行った。先ず、劣化源として３００Ｗの高圧水銀灯の光を試験片に２０cm離し１００時間照射した後、暗所に１時間以上外光を遮断した状態で保管し、その後常用光源Ｄ_６５の光を２００ルクスの照度で４分間照射し、照射を止めてから５分後のりん光輝度を測定する。次に高圧水銀灯による照射してない基準品の５分後のりん光輝度に対する相対値として維持率を求め、この結果より耐光性を評価した。この値が大きい方が耐光性が良いことになる。従来のＺｎＳ：Ｃｕ蛍光体のりん光輝度が２３％で，高圧水銀灯の照射により著しく低下しているのに対して、本発明の残光性蛍光体のりん光輝度は９５％とほとんど劣化せず極めて耐光性に優れている。
【００６０】
耐熱性については、石英ルツボに残光性蛍光体を１０ｇ入れ、マッフル炉中６００℃で３０分間酸化焼成を行い、焼成品のりん光輝度を測定し、焼成前の残光性蛍光体のりん光輝度対する百分率を算出し維持率として求める。本発明の残光性蛍光体は７６．６％の維持率を示した。
【００６１】
耐水性については、２５０ｍｌのプラスチック容器に残光性蛍光体を１０ｇ、純水を２００ｇ入れ、ローラーで３０ｒｐｍの速度で７２時間回転させる。次に固液分離し乾燥し、残光性蛍光体のりん光輝度を測定し、水に接触させる前のりん光輝度対する百分率を算出し維持率として求める。本発明の残光性蛍光体は４９．１％の維持率を示した。
【００６２】
［比較例１］
（ＮＨ_４）_２ＨＰＯ_４を添加しない以外実施例１と同様にして、比較例の残光性蛍光体(Sr_{０．９５５}Eu_０．０３Dy_{０．０１５})O・0.91(Al_０．９５B_０．０５)_２O_３を試作する。励起停止２０分後のりん光輝度は６１％、耐熱性試験の維持率は２５．１％、耐水性については維持率は０％で全く発光しなかった。
【００６３】
２価金属ＭがＳｒである場合の他の実施例２〜１３、リン酸化合物を含まない比較例２〜１０についても同様に試作し、同様に測定し、実施例１、比較例１を含めて結果を表１及び表２にまとめる。
【００６４】
【表１】

【００６５】
【表２】

【００６６】
［実施例１４］
蛍光体原料として、ＣａＣＯ_３を９５．５９ｇ（０．９５５ｍｏｌ）、Ａｌ_２Ｏ_３を９４．０１ｇ（０．９２２ｍｏｌ）、Ｅｕ_２Ｏ_３を２．６４ｇ（０．００７５ｍｏｌ）、Ｎｄ_２０_３を５．０５ｇ（０．０１５ｍｏｌ）、Ｈ_３ＢＯ_３を６．００ｇ（０．０９７ｍｏｌ）、及び（ＮＨ_４）_２ＨＰＯ_４を７．９２ｇ（０．０６０ｍｏｌ）を、混合媒体としてアルミナボール入りのセラミックポットに入れ、ローラーで２時間混合し蛍光体焼成前混合原料（以下原料生粉という）を得る。次に、原料生粉をアルミナルツボに入れ、還元雰囲気下１４００℃で５時間焼成し蛍光体焼成品を得る。次に焼成品を粉砕し、２００メッシュの篩を通し、本発明の(Ca_{０．９５５}Eu_{０．０１５}Nd_０．０３)O・0.97(Al_０．９５B_０．０５)_２O_３・0.03P_２O_５蛍光体を得る。
【００６７】
２価金属ＭがＣａである場合の他の実施例１５〜１８、リン酸化合物を含まない比較例１５〜１８についても同様に試作し、同様に測定し、実施例１４、比較例１４を含めて結果を表３、表４にまとめる。
【００６８】
これらより、本発明の残光性蛍光体は２価金属ＭがＳｒの緑色系の場合も、ＭがＣａの青色系の場合も、りん光輝度、耐熱性、及び耐水性において優れている。特に、耐水性に対するリン酸化合物の効果は絶大であり、ＭがＳｒの場合、リン酸化合物を加えない比較例では維持率がすべて０％であるのに対し、本発明品は大きく改善されている。
【００６９】
【表３】

【００７０】
【表４】

【００７１】
これらより、本発明の残光性蛍光体は２価金属ＭがＳｒの緑色系の場合、ＭがＣａの青色系の場合の何れもりん光輝度、耐熱性、及び耐水性において優れている。特に、耐水性に対するリン酸化合物の効果は絶大であり、ＭがＳｒの場合、リン酸化合物を加えない比較例では維持率がすべて０％であるのに対し、本発明品は大きく改善されている。
【００７２】
【発明の効果】
本発明は以上説明したように構成されているので、以下に記載されるような効果を奏する。
【００７３】
蓄光蛍光体をプラスチック、セラミックに混入させて使用する場合、これらを溶融させるため、蓄光蛍光体は３００〜７００℃程度の温度下にさらされる。また、屋外で使用する場合、特に水分との接触は起こりやすくなる。これに対し、本発明の残光性蛍光体は耐熱性、耐水性が向上され、さらに耐光性においても優れているため、このような条件下においても実用することができる。
【００７４】
また、本発明残光性蛍光体は焼成工程でできる焼成品は柔らかく、後工程での粉砕、フルイ等の処理を簡単化でき、収率を向上することができる。さらに、予期せぬ効果としてりん光輝度が向上する。
【図面の簡単な説明】
【図１】本発明の残光性蛍光体のリン酸化合物含有量と励起停止２０分後りん光輝度の関係を示す特性図である。
【図２】本発明の残光性蛍光体の耐熱試験におけるリン酸化合物含有量と維持率の関係を示す特性図である。
【図３】本発明の残光性蛍光体の耐水試験におけるリン酸化合物含有量と維持率の関係を示す特性図である。[0001]
[Industrial application fields]
The present invention relates to an afterglow phosphor that can be used as a phosphorescent phosphor, and more particularly, to an aluminate afterglow phosphor activated with europium having excellent heat resistance and water resistance.
[0002]
[Prior art]
Some phosphors have afterglow for a relatively long time in the dark when irradiated with sunlight or artificial light, and this phenomenon can be repeated many times, so it is called a phosphorescent phosphor. In recent years, social life has become more sophisticated and complicated, and interest in disaster prevention has further increased. In particular, the use of phosphorescent phosphors that shine in the dark is expanding in the field of disaster prevention. In addition, recently, phosphorescent phosphors are mixed in plastics and processed into plates, sheets, and the like, so that their applications are spreading in various fields.
[0003]
Conventionally, ZnS: Cu phosphors have been used as phosphorescent phosphors, but they have not been fully satisfied. This is because this phosphor has the following essential drawbacks. One is that the phosphorescence luminance (afterglow luminance) is not high enough to be confirmed over several tens of hours. The other problem is that the phosphorescence is photodegraded and colloidal zinc metal is deposited on the surface of the phosphor crystal, the appearance is changed to black, and the phosphorescence luminance is remarkably lowered. Such deterioration is particularly likely to occur under conditions of high temperature and high humidity. Usually, the surface of the ZnS: Cu phosphor is light-resistant to improve this defect, but it is difficult to prevent it completely. Therefore, the ZnS: Cu phosphor must be avoided from being used in places exposed to direct sunlight such as outdoors.
[0004]
It has recently been reported that afterglow properties are obtained by incorporating rare earth ions in the zinc sulfide phosphor matrix. ("Rare earth effect in nonrioactive night luminous phosphor ZnS: Pb, Cu" Hunan Shifan Daxue, Ziran Kexue XuebaoVol.14, No.1, page47-51 1991, X May and M.Hong, (Acta Scientiarium Naturalium Univ.Normalis Hunanensis ))
[0005]
Further, it has been reported that afterglow properties are exhibited by adding rare earth elements to Bi and Cu activated calcium sulfide phosphors. ("Study on effect of rare earth in blue-purple night-luminous phosphor CaS: Bi, Cu" Hunan Shifan Daxue, Ziran Kexue XuebaoVol.15, No.2, page145-148,1992, X Mao, S.Lian and Z .Wu (Hunan Normal Univ., Hunan, CHN))
[0006]
However, since these phosphors are sulfides, they have the drawbacks already described, and it can be easily imagined that they cannot be used outdoors.
[0007]
On the other hand, a compound represented by MAl ₂ O ₄ activated by divalent Eu, where M is a crystal composed of at least one metal element selected from the group consisting of calcium, strontium and barium. Japanese Patent Laid-Open No. 7-11250 discloses a phosphorescent phosphor. This phosphor is said to have solved the essential drawbacks of the zinc sulfide phosphor described above. Moreover, the matrix of this phosphor is already known from US Pat. No. 2,392,814 and US Pat. No. 3,294,699.
[0008]
Divalent Eu exhibits a broad spectrum emission due to indirect transition, and is affected by the preparation conditions and the structure of the host crystal. For example, depending on whether the host crystal is aluminate, gallate, borate or aluminum gallate, from ultraviolet to yellow It is generally known that light is emitted in a wide range.
[0009]
The present inventors have developed an afterglow phosphor that is activated with divalent europium and co-activated with a specific rare earth element using an alkaline earth metal salt of boro-aluminate as a phosphor matrix, and has been patented in the United States. Applied and patent granted. (USP5376303) In addition, the present inventors used the same phosphor matrix, tested more coactivators, and applied for patents for newly obtained knowledge. (Japanese Patent Application No. 6-147912)
[0010]
[Problems to be solved by the invention]
When the phosphorescent phosphor is used by being mixed with plastic or ceramic, the phosphorescent phosphor is exposed to a temperature of about 300 to 700 ° C. in order to melt them. Therefore, even when there is a process for molding at such a high temperature, a phosphorescent phosphor that does not deteriorate the light emission performance is required. Further, when used outdoors, contact with moisture is likely to occur, and when used in such an environment, water resistance is also important.
[0011]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present inventor has intensively studied the components that promote the crystal growth of the afterglow phosphor and stabilize the crystals. As a result, the problem can be solved by simultaneously containing boric acid and phosphoric acid. I found.
[0012]
That is, the afterglow phosphor of the present invention is an aluminate phosphor activated with divalent europium, and its chemical composition formula is in the following range.

However, M in the composition formula is at least one selected from the group of divalent metals consisting of Mg, Ca, Sr, Ba, and Zn, Q is a coactivator, and Mn, Zr, Nb, Pr , Nd, Gd, Tb, Dy, Ho, Er, Tm, Yb and at least one selected from the group consisting of Lu.
[0013]
The fluorescent color and afterglow color can be selected by further adjusting the above composition to the following specific range.
[0014]
When preparing an afterglow phosphor emitting green light having an emission peak wavelength near 520 nm, the composition range is selected as follows. That is, an aluminate phosphor activated with divalent europium is an afterglow phosphor whose crystal structure is in the following range and whose crystal structure is mainly in the monoclinic system.

However, M in the composition formula is 70 mol% or more of Sr.
[0015]
When preparing an afterglow phosphor emitting blue light having an emission peak wavelength of around 440 nm, the composition range is selected as follows. Namely, an afterglow phosphor characterized in that the aluminate phosphor activated with divalent europium has a chemical composition formula in the following range and the crystal structure is mainly monoclinic. And

However, M in the composition formula is 70 mol% or more of Ca.
[0016]
When preparing an afterglow phosphor emitting blue-green light whose emission peak wavelength is around 490 nm, the following composition range is selected. Namely, an afterglow phosphor characterized in that the aluminate phosphor activated with divalent europium has a chemical composition formula in the following range and the crystal structure is mainly composed of orthorhombic system. And

However, M in the composition formula is 70 mol% or more of Sr.
[0017]
In particular, the afterglow phosphor emitting blue-green light having an emission peak wavelength near 490 nm is preferably selected in the following composition range from the viewpoint of emission luminance and afterglow luminance. Namely, an afterglow phosphor characterized in that the aluminate phosphor activated with divalent europium has a chemical composition formula in the following range and the crystal structure is mainly composed of orthorhombic system. And

However, M in the composition formula is Sr.
[0018]
The activator and coactivator introduced into the afterglow phosphor of the present invention greatly affects the fluorescence color and afterglow luminance. For practical use, adjust to the ranges shown below.
[0019]
The Eu concentration p of the activator is adjusted to a range in which 0.001 mol or more and 0.5 mol or less of Sr of the matrix is substituted for 1 mol of the phosphor. This is because if the amount is less than 0.0001 mol, light absorption is deteriorated, resulting in a decrease in afterglow luminance. Conversely, if it exceeds 0.5 mol, concentration quenching occurs and the afterglow luminance decreases. A more preferable range of p is 0.001 ≦ p ≦ 0.06, and the afterglow luminance is further increased in this range.
[0020]
By introducing the coactivator, the emission of Eu becomes afterglow. As the coactivator, at least one selected from the group consisting of Mn, Zr, Nb, Pr, Nd, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu is effective.
[0021]
Dy is effective for improving the persistence when the divalent metal M of the phosphor matrix is Sr, and the optimum concentration range of the Dy concentration q is 0.0005 or more and 0.03 or less.
[0022]
Nd is particularly effective for improving afterglow luminance when the divalent metal M of the phosphor matrix is Ca in particular, and the optimum range of the Nd concentration q is 0.0005 or more and 0.03 or less.
[0023]
A synergistic effect is exhibited by activating these coactivators Dy and Nd secondly.
[0024]
When Dy is selected as the first coactivator, the preferable range of the Mn concentration q of the second coactivator is 0.0001 or more and 0.06 or less, and more preferably 0.0005 or more and 0. .02 or less.
[0025]
When Dy is selected as the first coactivator, the preferred range of the Tm concentration q of the second coactivator is 0.0003 or more and 0.02 or less, and more preferably 0.0004 or more and 0. .01 or less.
[0026]
When Dy is selected as the first coactivator, the preferable range of the Lu concentration q of the second coactivator is 0.0001 or more and 0.06 or less, and more preferably 0.0004 or more and 0. .04 or less.
[0027]
When Dy is selected as the first coactivator, the preferable range of the Nb concentration q of the second coactivator is 0.0001 or more and 0.08 or less, and more preferably 0.0003 or more and 0. .04 or less.
[0028]
When Dy is selected as the first coactivator, the preferred range of the Yb concentration q of the second coactivator is 0.0002 or more and 0.04 or less, and more preferably 0.0003 or more and 0. .01 or less.
[0029]
When Dy is selected as the first coactivator, the preferred range of the Zr concentration q of the second coactivator is 0.002 or more and 0.70 or less.
[0030]
When Dy is selected as the first coactivator, the preferred range of the Er concentration q of the second coactivator is 0.0001 or more and 0.03 or less. More preferred is a range of 0.0005 or more and 0.02 or less.
[0031]
When Dy is selected as the first coactivator, the preferred range of the Pr concentration q of the second coactivator is 0.0001 or more and 0.04 or less. More preferred is a range of 0.0005 or more and 0.03 or less.
[0032]
When Nd is introduced as the first coactivator, the preferable range of the Tm concentration q of the second coactivator is 0.0001 or more and 0.06 or less, and more preferably 0.0005 or more and 0. .02 or less.
[0033]
When Nd is introduced as the first coactivator, the preferred range of the Pr concentration q of the second coactivator is 0.0001 or more and 0.06 or less, and more preferably 0.0005 or more and 0. .02 or less.
[0034]
When Nd is introduced below as the first coactivator, the preferred range of the Ho concentration q of the second coactivator is 0.0001 or more and 0.06 or less, and more preferably 0.0005 or more, The range is 0.02 or less.
[0035]
When Nd is introduced below as the first coactivator, the preferred range of the Dy concentration q of the second coactivator is 0.0001 or more and 0.06 or less, more preferably 0.0005 or more, The range is 0.02 or less.
[0036]
With respect to the matrix composition of the afterglow phosphor of the present invention, the afterglow characteristics are further greatly improved by replacing a part of aluminum with boron. Boron is suitably substituted in the range of 0.0001 mol to 0.5 mol of the total number of moles of aluminum, more preferably in the range from 0.005 mol to 0.25 mol, most preferably 0. .05 moles. In order to introduce boron, it is preferable to charge aluminum by subtracting an amount corresponding to it.
[0037]
The phosphate compound concentration k is preferably in the range of 0.001 to 0.2, more preferably in the range of 0.01 to 0.1, and most preferably in the range of 0.03 to 0.05.
[0038]
The afterglow phosphor of the present invention is fired as a raw material at a high temperature such as a metal oxide such as SrO, MgO, Al ₂ O ₃ , Eu ₂ O ₃ or CaCO ₃ , SrCO ₃ , BaCO _3. Select a compound that easily becomes an oxide. Such compounds include nitrates, oxalates, hydroxides and the like in addition to carbonates. As the boron compound, boric acid or an alkaline earth borate can be used, and boric acid is particularly preferable. In order to introduce phosphoric acid into the composition of the persisting phosphor, phosphoric acid, anhydrous phosphoric acid, ammonium phosphate, alkaline earth element phosphates and the like can be preferably used.
[0039]
The purity of the raw material greatly affects the afterglow brightness, and is preferably 99.9% or more, and more preferably 99.99% or more. The afterglow fluorescent substance of this invention is obtained by baking the raw material which mixed these flux at the temperature of 1200 degreeC or more and 1600 degrees C or less under reducing atmosphere, and grind | pulverizing and sieving a baked product. In addition, the mixing ratio of the raw materials can be determined by mixing theoretical amounts for obtaining the target composition.
[0040]
The afterglow fluorescent substance of this invention is obtained by baking the raw material which mixed these in the temperature range of 1200 degreeC or more and 1600 degrees C or less under reducing atmosphere, and grind | pulverizing and sieving a baked product. In addition, the mixing ratio of the raw materials can be determined by mixing theoretical amounts for obtaining the target composition.
[0041]
[Action]
The afterglow phosphor of the present invention basically exhibits strong light emission due to the divalent Eu of the activator, but the divalent Eu absorbs in a wide range from the visible light to the ultraviolet region, and thus, like natural light. Excited in a wide range of wavelengths and exhibits highly efficient light emission (fluorescence). Further, as a coactivator, the phosphor matrix is doped with at least one selected from the group consisting of Mn, Zr, Nb, Pr, Nd, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. Afterglow phenomenon appears.
[0042]
In the afterglow phosphor of the present invention, by containing boron, the crystallinity of the aluminate is improved, and the afterglow time and afterglow brightness are effectively improved by stabilizing the emission center and the capture center. Can be estimated. In addition, boron acts as a flux at the same time, promotes crystal growth of the phosphor, and can greatly improve phosphorescence brightness.
[0043]
When the total number of moles of oxides of divalent metal, activator, and coactivator and the total number of moles of alumina and boric acid are approximately 1: 1, that is, n = 1, the result of analysis by X-ray diffraction shows that The structure is a monoclinic system of SrAl ₂ O ₄ type and exhibits green light emission having a peak at a wavelength of 520 nm.
[0044]
However, this afterglow phosphor has poor heat resistance, and with the addition of boric acid, the heat resistance further deteriorates, and the fired product becomes hard, and it becomes difficult to process pulverization and sieving in the subsequent steps. On the other hand, heat resistance and water resistance are improved by adding and firing a phosphoric acid compound as a composition raw material.
[0045]
Most of the added boric acid forms a mixed crystal with alumina and is incorporated into the phosphor composition, but some excess boric acid forms a mixed crystal with phosphoric acid compounds and divalent metals to melt between the phosphor particles. It is thought that it has a function to prevent the reaction, which contributes to the improvement of heat resistance. Moreover, since this mixed crystal is insoluble in water and coats the particle surface of the afterglow phosphor, it imparts water resistance to the afterglow phosphor.
[0046]
When a phosphoric acid compound is added at the time of firing the afterglow phosphor and fired, most of it is contained in the composition as a phosphoric acid compound. (Sr _0.955 Eu _0.03 Dy _0.015 ) O.0.91 (Al _0.95 B _0.05 ) ₂ O _{3 in} order to _examine the effect on the content and phosphorescence brightness, heat resistance and water resistance. · kP ₂ O ₅ a prototype afterglow phosphor were evaluated their characteristics with respect to the content k of phosphoric acid compound. Here, heat resistance and water resistance were measured by the following method.
[0047]
For heat resistance, 10 g of afterglow phosphor is put in a quartz crucible, oxidized and fired at 600 ° C. for 30 minutes in a muffle furnace, the phosphorescence brightness of the fired product is measured, and the phosphor of the afterglow phosphor before firing is measured. The percentage with respect to the light intensity is calculated and obtained as the maintenance rate.
[0048]
As for water resistance, 10 g of afterglow phosphor and 200 g of pure water are placed in a 250 ml plastic container, and rotated for 72 hours at a speed of 30 rpm with a roller. Next, solid-liquid separation and drying are performed, and the phosphorescence luminance of the afterglow phosphor is measured, and the percentage of the phosphorescence luminance before being brought into contact with water is calculated and obtained as a maintenance rate.
[0049]
Based on these measurement results, FIGS. 1 to 3 show relationships with phosphorescent brightness, heat resistance, and water resistance phosphoric acid content k, respectively. As can be seen from FIG. 1, the phosphoric acid content is effective in improving the phosphorescence brightness 20 minutes after the excitation is stopped in a wide range of k ≦ 0.1, and the highest is around k = 0.05. In the range of k> 0.1, the phosphorescence luminance is lower than that containing no phosphate compound.
[0050]
From the results of the heat resistance test shown in FIG. 2, it can be seen that the inclusion of the phosphoric acid compound is effective in heat resistance over a wide concentration range, and k ≧ 0.00005 is effective in heat resistance. The range of 0.02 ≦ k ≦ 0.05 is most preferable.
[0051]
The water resistance of the afterglow phosphor containing no phosphoric acid compound is 0% in all cases. This is because the phosphor crystal is destroyed and no light is emitted. As shown in FIG. 3, the effect of phosphoric acid on water resistance is effective over a wide range. Actually, if 0 <k, it is effective, but the maintenance rate is 20% in the range of 0.001 ≦ k ≦ 0.6. The maintenance ratio exceeds 40% in the range of 0.02 ≦ k ≦ 0.1, and the vicinity of k = 0.05 is most preferable especially when the maintenance ratio exceeds 50%.
[0052]
Judging from these, the phosphate compound concentration k is preferably in the range of 0.001 ≦ k ≦ 0.2, more preferably in the range of 0.01 ≦ k ≦ 0.1, and 0.03 ≦ k ≦ 0. A range of .05 is most preferred. However, the value of k should be selected depending on the use environment.
[0053]
As a result of X-ray diffraction analysis of the phosphor crystal structure when the divalent metal M is Sr, the afterglow phosphor crystal containing no phosphate compound shows a monoclinic structure of SrAl ₂ O _4. However, when phosphoric acid is contained at the same time as boric acid, crystals of different types of α-Sr ₃ P ₂ O ₈ come to be mixed. Further, when phosphoric acid is increased and n / 4 ≦ k, crystals of α-Sr ₃ P ₂ O ₅ are completely formed. Further, when the divalent metal M is Ca, the afterglow phosphor crystal containing no phosphoric acid compound shows a monoclinic structure of CaAl ₂ O ₄ , but if it contains even a little phosphoric acid, CaP ₂ Different types of O ₆ crystals are mixed.
[0054]
【Example】
[Example 1]
As phosphor materials, 140.98 g (0.955 mol) of SrCO ₃ , 88.14 g (0.865 mol) of Al ₂ O ₃ , 5.28 g (0.015 mol) of Eu ₂ O ₃ , and Dy ₂ O ₃ were used. 2.80 g (0.0075 mol), 5.63 g (0.091 mol) of H ₃ BO ₃ , and 7.92 g (0.060 mol) of (NH ₄ ) ₂ HPO ₄ , ceramic containing alumina balls as a mixing medium It puts into a pot and mixes with a roller for 2 hours to obtain a mixed raw material before phosphor firing (hereinafter referred to as raw raw powder). Next, raw raw powder is put in an alumina crucible and fired at 1400 ° C. for 5 hours in a reducing atmosphere to obtain a fired phosphor. Then pulverized calcined product, passed through a 200 mesh sieve, the present invention _{(Sr 0.955 Eu 0.03 Dy 0.015)} O · 0.91 (Al 0.95 B 0.05) 2 O 3 · 0.03 A P ₂ O ₅ phosphor is obtained.
[0055]
The resulting phosphor emits light in a wide range from visible to ultraviolet, and is excited by a black light or germicidal lamp to emit light. Therefore, it can be applied to fluorescent mercury lamps and low-pressure mercury vapor discharge lamps. The test according to the use of the phosphor is performed according to JIS K 5120.
[0056]
Add 0.5 g of acrylic resin varnish to 1 g of the phosphor sample, knead carefully so as not to crush the sample, apply it to an aluminum plate so that the sample has a thickness of 100 mg / cm ² or more, and dry it. A test piece was obtained. This test piece is used for measurement of fluorescent color, phosphorescence luminance, and light resistance.
[0057]
For the measurement of fluorescent color, UV light of 253.7 nm was applied to the sample, the spectral distribution of fluorescence was obtained with a spectrophotometer, and the chromaticity of the CIE color system was calculated. It is clear that the fluorescent chromaticity is x = 0.248, y = 0.561, exhibits a green system with high visibility, and has excellent basic characteristics as a phosphorescent phosphor.
[0058]
The phosphorescence brightness was measured with reference to JIS Z 9100 (Method of measuring phosphorescence brightness of phosphorescent safety sign board). After the test piece was kept in a state of blocking the external light more than 3 hours in the dark, the light of the common light source D ₆₅ to the test piece was irradiated for 4 minutes at an illuminance of 200 lux, phosphorus after stopping the irradiation after 20 minutes The relative brightness with the phosphorescence brightness of (Sr _0.955 Eu _0.03 Dy _0.015 Tm _0.003 ) O. (Al _0.95 B _0.05 ) ₂ O ₃ phosphor as 100%. It was measured. The phosphorescence luminance of the afterglow phosphor of the present invention (Sr _0.952 Eu _0.03 Dy _0.015 ) _O.0.91 (Al _0.95 B _0.05 ) ₂ O ₃ .0.03P ₂ O ₅ is 98. %Met.
[0059]
The light resistance test was performed as follows with reference to the light resistance test method of the luminescent paint in JIS K 5671. First, high-pressure mercury lamp of 300W as the deterioration source was irradiated 20cm apart 100 hours the specimen light, and stored in a state of blocking the external light more than 1 hour in the dark, then conventional light source D ₆₅ light of 200 lux Irradiate with illuminance for 4 minutes, and measure phosphorescence brightness 5 minutes after stopping the irradiation. Next, the maintenance factor was obtained as a relative value to the phosphorescence brightness after 5 minutes of the reference product not irradiated with the high-pressure mercury lamp, and the light resistance was evaluated from this result. The higher this value, the better the light resistance. The phosphorescence brightness of the conventional ZnS: Cu phosphor is 23%, which is significantly reduced by irradiation with a high-pressure mercury lamp, whereas the phosphorescence brightness of the afterglow phosphor of the present invention is almost degraded to 95%. It is extremely excellent in light resistance.
[0060]
For heat resistance, 10 g of afterglow phosphor is put in a quartz crucible, oxidized and fired at 600 ° C. for 30 minutes in a muffle furnace, the phosphorescence brightness of the fired product is measured, and the phosphor of the afterglow phosphor before firing is measured. The percentage with respect to the light intensity is calculated and obtained as the maintenance rate. The afterglow phosphor of the present invention showed a maintenance rate of 76.6%.
[0061]
As for water resistance, 10 g of afterglow phosphor and 200 g of pure water are placed in a 250 ml plastic container, and rotated for 72 hours at a speed of 30 rpm with a roller. Next, solid-liquid separation and drying are performed, and the phosphorescence luminance of the afterglow phosphor is measured, and the percentage of the phosphorescence luminance before being brought into contact with water is calculated and obtained as a maintenance rate. The persistence phosphor of the present invention showed a maintenance rate of 49.1%.
[0062]
[Comparative Example 1]
The afterglow phosphor (Sr _0.955 Eu _0.03 Dy _0.015 ) O.0.91 (Al _0.95 B) in the same manner as in Example 1 except that (NH ₄ ) ₂ HPO ₄ was not added. _0.05 ) Prototype ₂ O ₃ The phosphorescence luminance after 61 minutes of excitation was 61%, the heat resistance test maintenance rate was 25.1%, and the water resistance maintenance rate was 0%, and no light was emitted.
[0063]
Other Examples 2 to 13 in which the divalent metal M is Sr and Comparative Examples 2 to 10 not containing a phosphate compound were also produced in the same manner and measured in the same manner, including Example 1 and Comparative Example 1. The results are summarized in Tables 1 and 2.
[0064]
[Table 1]

[0065]
[Table 2]

[0066]
[Example 14]
As phosphor materials, 95.59 g (0.955 mol) of CaCO ₃ , 94.01 g (0.922 mol) of Al ₂ O ₃ , 2.64 g (0.0075 mol) of Eu ₂ O ₃ , and Nd ₂ O ₃ were used. Ceramic containing alumina balls as a mixing medium of 5.05 g (0.015 mol), 6.00 g (0.097 mol) of H ₃ BO ₃ , and 7.92 g (0.060 mol) of (NH ₄ ) ₂ HPO ₄ It puts into a pot and mixes with a roller for 2 hours to obtain a mixed raw material before phosphor firing (hereinafter referred to as raw raw powder). Next, raw raw powder is put in an alumina crucible and fired at 1400 ° C. for 5 hours in a reducing atmosphere to obtain a fired phosphor. Next, the fired product is pulverized, passed through a 200-mesh sieve, and (Ca _0.955 Eu _0.015 Nd _0.03 ) O.0.97 (Al _0.95 B _0.05 ) ₂ O _{3 .0.03 of the} present invention. A P ₂ O ₅ phosphor is obtained.
[0067]
Other Examples 15 to 18 in which the divalent metal M is Ca and Comparative Examples 15 to 18 not containing a phosphate compound were also produced in the same manner and measured in the same manner, including Example 14 and Comparative Example 14. The results are summarized in Tables 3 and 4.
[0068]
Accordingly, the afterglow phosphor of the present invention is excellent in phosphorescence brightness, heat resistance, and water resistance both when the divalent metal M is Sr green and when M is Ca blue. In particular, the effect of the phosphoric acid compound on water resistance is enormous. When M is Sr, the maintenance rate is 0% in the comparative examples in which no phosphoric acid compound is added, whereas the product of the present invention is greatly improved. Yes.
[0069]
[Table 3]

[0070]
[Table 4]

[0071]
From these results, the afterglow phosphor of the present invention is excellent in phosphorescence brightness, heat resistance, and water resistance both when the divalent metal M is Sr green and when M is Ca blue. In particular, the effect of the phosphoric acid compound on water resistance is enormous. When M is Sr, the maintenance rate is 0% in the comparative examples in which no phosphoric acid compound is added, whereas the product of the present invention is greatly improved. Yes.
[0072]
【The invention's effect】
Since the present invention is configured as described above, the following effects can be obtained.
[0073]
When the phosphorescent phosphor is used by mixing it with plastic or ceramic, the phosphorescent phosphor is exposed to a temperature of about 300 to 700 ° C. in order to melt them. Further, when used outdoors, contact with moisture is particularly likely to occur. On the other hand, the afterglow phosphor of the present invention has improved heat resistance and water resistance, and is excellent in light resistance, and can be put to practical use under such conditions.
[0074]
Further, the afterglow phosphor of the present invention is soft in a fired product that can be produced in the firing process, can simplify the processes such as pulverization and sieving in the subsequent process, and can improve the yield. Furthermore, phosphor brightness is improved as an unexpected effect.
[Brief description of the drawings]
FIG. 1 is a characteristic diagram showing the relationship between the content of a phosphoric acid compound of an afterglow phosphor of the present invention and phosphorescence luminance after 20 minutes of excitation termination.
FIG. 2 is a characteristic diagram showing the relationship between the phosphate compound content and the retention rate in the heat resistance test of the afterglow phosphor of the present invention.
FIG. 3 is a characteristic diagram showing the relationship between the phosphate compound content and the retention rate in the water resistance test of the afterglow phosphor of the present invention.

Claims (3)

An afterglow phosphor characterized in that the aluminate phosphor activated with divalent europium has a chemical composition formula in the following range.
(M _1-pr Eu _p Q _q ) O.n (Al _1-m B _m ) ₂ O ₃ .kP ₂ O ₅
0.0001 ≦ p ≦ 0.5
0.0001 ≦ q ≦ 0.5
0.5 ≦ n <1.5
0.0001 ≦ m ≦ 0.5
0 <k ≦ 0.2
0.0002 ≦ p + q ≦ 0.75
However, M is C a in the composition formula is at least one selected from the group of S r or Ranaru divalent metal, Q is a coactivator, Mn, Zr, Nb, Pr, Nd, D y, is Ho, Er, Tm, Yb, and at least one selected from the group consisting of Lu. The aluminate phosphor activated by divalent europium has a chemical composition formula in the following range, and its crystal structure is mainly monoclinic. Afterglow phosphor.
(M _1-pr Eu _p Q _q ) O.n (Al _1-m B _m ) ₂ O ₃ .kP ₂ O ₅
0.0001 ≦ p ≦ 0.5
0.0001 ≦ q ≦ 0.5
0.5 ≦ n <1.5
0.0001 ≦ m ≦ 0.5
0 <k ≦ 0.2
0.0002 ≦ p + q ≦ 0.75
However, M in the composition formula is 70 mol% or more of Sr. The aluminate phosphor activated by divalent europium has a chemical composition formula in the following range, and its crystal structure is mainly monoclinic. Afterglow phosphor.
(M _1-pr Eu _p Q _q ) O.n (Al _1-m B _m ) ₂ O ₃ .kP ₂ O ₅
0.0001 ≦ p ≦ 0.5
0.0001 ≦ q ≦ 0.5
0.5 ≦ n <1.5
0.0001 ≦ m ≦ 0.5
0 <k ≦ 0.2
0.0002 ≦ p + q ≦ 0.75
However, in the composition formula, Ca is 70 mol% or more.

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