JPH06299150A - Fluorescent material and its production - Google Patents
Fluorescent material and its productionInfo
- Publication number
- JPH06299150A JPH06299150A JP9293193A JP9293193A JPH06299150A JP H06299150 A JPH06299150 A JP H06299150A JP 9293193 A JP9293193 A JP 9293193A JP 9293193 A JP9293193 A JP 9293193A JP H06299150 A JPH06299150 A JP H06299150A
- Authority
- JP
- Japan
- Prior art keywords
- barrier layer
- phosphor
- fluorescent region
- fluorescent
- region
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- Luminescent Compositions (AREA)
Abstract
Description
【0001】[0001]
【産業上の利用分野】本発明は特にCRT等に用いられ
る電子線励起蛍光体に関するもので、画像表示装置等の
ディスプレイ分野等に用いられる蛍光体及びその製造方
法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention particularly relates to an electron beam excited phosphor used in a CRT or the like, and relates to a phosphor used in a display field such as an image display device and a method for producing the same.
【0002】[0002]
【従来の技術】現在、高輝度、高品位で、ある程度大画
面が得られることから、CRTがディスプレイとして最
も多く用いられている。現在CRTに用いられている蛍
光体は、II−VI族化合物半導体、または酸化物等よりな
る母体に適当な付活剤を混ぜたものが多い。具体的に
は、ZnS:Ag、ZnS:Cu、Al、Y2 O3 S:
Eu3+等である。CRTには、1本の電子ビームで蛍光
面全面を走査する構成のため、広い領域を走査するため
には走査する蛍光スクリーンの大きさに応じて電子銃を
それから離さなければならない、即ち、深い奥行きが必
要であるという課題がある。2. Description of the Related Art At present, CRTs are most often used as displays because of their high brightness, high quality, and relatively large screens. Most of the phosphors currently used in CRTs are those obtained by mixing an appropriate activator with a matrix composed of II-VI group compound semiconductors or oxides. Specifically, ZnS: Ag, ZnS: Cu, Al, Y 2 O 3 S:
Eu 3+ and the like. Since the CRT is configured to scan the entire phosphor screen with one electron beam, in order to scan a large area, the electron gun has to be separated from it according to the size of the phosphor screen to be scanned, that is, the deep There is a problem that depth is required.
【0003】そこで近年、この課題を解決するフラット
パネルディスプレイとしてカラーフラットパネル(以後
CFPと呼ぶ)が開発された。これはエス・アイ・ディ
ー・´85ダイジェスト、185ページ〜186ペー
ジ、1985年4月(SID′85Digest 185p-186p,Apr.1
985)等で発表されている。Therefore, in recent years, a color flat panel (hereinafter referred to as CFP) has been developed as a flat panel display that solves this problem. This is the S'D'85 digest, pages 185-186, April 1985 (SID'85 Digest 185p-186p, Apr.1
985) etc.
【0004】図6にその電極構成例を示す。CFPは、
複数の線状カソード51からグリッド52を使って形成
された複数の電子ビームが、それぞれ偏向電極群53で
偏向され蛍光スクリーン54上を走査する構成である。
個々の電子ビームが走査を担当する領域は蛍光スクリー
ン54の一部分である。従って、個々の電子ビームの偏
向角は小さくても、複数の電子ビームを用いるので広い
スクリーン全面に画像表示することができる。即ち、C
FPの奥行きは、同じ面積のスクリーンを走査するため
に必要なCRTの奥行きよりはるかに薄くてよい。FIG. 6 shows an example of the electrode structure. CFP is
A plurality of electron beams formed from a plurality of linear cathodes 51 using a grid 52 are each deflected by a deflection electrode group 53 to scan a fluorescent screen 54.
The area where the individual electron beams are responsible for scanning is part of the phosphor screen 54. Therefore, even if the deflection angle of each electron beam is small, since a plurality of electron beams are used, an image can be displayed on the entire surface of a wide screen. That is, C
The FP depth may be much thinner than the CRT depth required to scan the same area screen.
【0005】現在、奥行きが50mm〜80mmとCR
Tに比べてはるかに短いCFPが試作されている。カソ
ード・アノード間には、図6に示すように複数のグリッ
ド52と偏向電極群53が近接して設けられており、1
0kV程度の高電圧が印加されている。Currently, the depth is 50 mm to 80 mm and CR.
A CFP, which is much shorter than the T, is being prototyped. As shown in FIG. 6, a plurality of grids 52 and a deflection electrode group 53 are provided close to each other between the cathode and the anode.
A high voltage of about 0 kV is applied.
【0006】図7にCFPの蛍光スクリーン54の断面
図を示す。ガラス製のフェースプレート55の表面に所
定の厚さの蛍光体層56が設けられ、その上に膜厚が約
100nm程度のアルミニウム製のメタルバック57が
設けられている。従来、蛍光体層56を構成する蛍光体
には一般のCRTと同じものが用いられていた。FIG. 7 shows a sectional view of a CFP fluorescent screen 54. A phosphor layer 56 having a predetermined thickness is provided on the surface of a glass face plate 55, and an aluminum metal back 57 having a thickness of about 100 nm is provided thereon. Conventionally, the same phosphor as a general CRT has been used as the phosphor constituting the phosphor layer 56.
【0007】[0007]
【発明が解決しようとする課題】CFPにおける蛍光体
の発光効率ηはCRTと同じ蛍光体を用いているにも関
わらずCRTに比べてかなり低かった。具体的には、C
RTではη=20%程度と高いのに対して、CFPでは
η=約12%(V=10kV時)と劣る。発光効率ηの
違いは、CFPとCRTで加速電圧Vが異なるため生ず
る。通常のCRTにおける加速電圧Vは20〜30kV
である。ところが、CFPにおける加速電圧Vは10k
V程度と低い。The luminous efficiency η of the phosphor in CFP was considerably lower than that of CRT, despite using the same phosphor as CRT. Specifically, C
It is as high as η = 20% at RT, but is inferior as η = about 12% (at V = 10 kV) in CFP. The difference in luminous efficiency η occurs because the acceleration voltage V is different between CFP and CRT. The acceleration voltage V in a normal CRT is 20 to 30 kV
Is. However, the acceleration voltage V in CFP is 10k.
It is as low as V.
【0008】CFPにおける加速電圧がCRTに比べて
低く設定されているのは以下の理由による。CFPは、
電極間隔が狭く、また電界集中を生じ易い構成のため、
それらの間で高電圧により放電がおこり易い。放電は画
像を乱すばかりか電極や蛍光面を傷つけてしまう。従っ
てCFPではCRTのような高加速電圧を与えにくい。
もしカソード・アノード間に印加する電圧を従来よりさ
らに低くすることができれば、放電開始電圧が下がるた
め、よりCFPの奥行きを短くすることができる。ま
た、偏向電圧も低減することができる。ところが、従来
の蛍光体を用いる限り、発光効率ηが非常に低くなって
しまうため、これ以上大幅な加速電圧低減はできなかっ
た。The accelerating voltage in the CFP is set lower than that in the CRT for the following reason. CFP is
Because the electrode spacing is narrow and the electric field concentration is easy to occur,
A high voltage is likely to cause a discharge between them. The electric discharge not only disturbs the image but also damages the electrodes and the phosphor screen. Therefore, it is difficult for CFP to apply a high acceleration voltage like CRT.
If the voltage applied between the cathode and the anode can be made lower than in the conventional case, the discharge start voltage is lowered, and the depth of the CFP can be further shortened. Also, the deflection voltage can be reduced. However, as long as the conventional phosphor is used, the light emission efficiency η becomes extremely low, so that the acceleration voltage cannot be reduced further.
【0009】本発明は、前記従来の課題を解決するた
め、特に低加速電圧の電子ビームで励起しても発光効率
が高い蛍光体を提供することを目的とする。In order to solve the above conventional problems, it is an object of the present invention to provide a phosphor having a high luminous efficiency even when excited by an electron beam having a low acceleration voltage.
【0010】[0010]
【課題を解決するための手段】前記目的を達成するた
め、本発明の蛍光体は、蛍光領域と、前記蛍光領域と接
合を形成してその表面を覆う障壁層を備え、少なくとも
前記障壁層の伝導帯最下端ポテンシャルが前記蛍光領域
のそれより高いか、または前記障壁層の価電子帯最上端
ポテンシャルが前記蛍光領域のそれより低いという構成
を備えたものである。In order to achieve the above object, the phosphor of the present invention comprises a fluorescent region and a barrier layer which forms a junction with the fluorescent region and covers the surface thereof, and at least the barrier layer is formed. The configuration is such that the conduction band lowest end potential is higher than that of the fluorescent region, or the valence band uppermost potential of the barrier layer is lower than that of the fluorescent region.
【0011】前記構成においては、障壁層の伝導帯最下
端ポテンシャルが蛍光領域のそれより浅く、かつ前記障
壁層の価電子帯最上端ポテンシャルが前記蛍光領域のそ
れより低いことが好ましい。In the above structure, it is preferable that the conduction band bottom end potential of the barrier layer is shallower than that of the fluorescent region, and the valence band top end potential of the barrier layer is lower than that of the fluorescent region.
【0012】また前記構成においては、蛍光領域に付活
剤が存在し、前記付活剤がアクセプター不純物であっ
て、かつ障壁層の伝導帯最下端ポテンシャルが蛍光領域
のそれより高いことが好ましい。Further, in the above structure, it is preferable that an activator is present in the fluorescent region, the activator is an acceptor impurity, and the conduction band bottom end potential of the barrier layer is higher than that in the fluorescent region.
【0013】また前記構成においては、少なくとも障壁
層の伝導帯最下端ポテンシャルが表面に近づくにつれて
高いか、または前記障壁層の価電子帯最上端ポテンシャ
ルが表面に近づくにつれて低いことが好ましい。In the above structure, it is preferable that at least the conduction band bottom end potential of the barrier layer is higher as it approaches the surface, or the valence band top end potential of the barrier layer is lower as it approaches the surface.
【0014】また前記構成においては、障壁層の導電型
または活性不純物濃度が蛍光領域と異なることが好まし
い。また前記構成においては、蛍光領域及び障壁層が、
硫化亜鉛、セレン化亜鉛、硫化カドミウム及びセレン化
カドミウムから選ばれる少なくとも一つの化合物半導
体、または前記化合物半導体にさらにマグネシウム、カ
ルシウム、ストロンチウム、バリウム及びマンガンから
選ばれる少なくとも一つの元素を含む化合物半導体であ
ることが好ましい。In the above structure, it is preferable that the barrier layer has a conductivity type or an active impurity concentration different from that of the fluorescent region. In the above structure, the fluorescent region and the barrier layer are
Zinc sulfide, zinc selenide, at least one compound semiconductor selected from cadmium sulfide and cadmium selenide, or a compound semiconductor further containing at least one element selected from magnesium, calcium, strontium, barium and manganese in the compound semiconductor. It is preferable.
【0015】また前記構成においては、蛍光領域及び障
壁層が、Y2 O3 及びY2 O2 Sから選ばれる少なくと
も一つの元素を含む化合物半導体であることが好まし
い。また前記構成においては、障壁層の厚さが1nm以
上100nm以下であることが好ましい。Further, in the above structure, it is preferable that the fluorescent region and the barrier layer are a compound semiconductor containing at least one element selected from Y 2 O 3 and Y 2 O 2 S. Further, in the above structure, the thickness of the barrier layer is preferably 1 nm or more and 100 nm or less.
【0016】また前記構成においては、少なくとも加速
電圧が15kV以下の電子ビームに対して用いられるこ
とが好ましい。次に本発明の蛍光体の製造方法は、障壁
層を構成する元素を含有する気体または液体中に蛍光体
粒子を置き、前記蛍光体粒子の表面に障壁層をエピタキ
シャル成長させ、蛍光領域と、前記蛍光領域と接合を形
成してその表面を覆う障壁層を備え、少なくとも前記障
壁層の伝導帯最下端ポテンシャルが前記蛍光領域のそれ
より高いか、または前記障壁層の価電子帯最上端ポテン
シャルが前記蛍光領域のそれより低い蛍光体を得ること
を特徴とする。Further, in the above structure, it is preferable to use for an electron beam having an accelerating voltage of at least 15 kV. Next, the method for producing a phosphor of the present invention comprises placing phosphor particles in a gas or a liquid containing an element forming a barrier layer, epitaxially growing a barrier layer on the surface of the phosphor particles, and a fluorescent region, A barrier layer that forms a junction with the fluorescent region and covers the surface thereof, at least the lowest conduction band potential of the barrier layer is higher than that of the fluorescent region, or the uppermost valence band potential of the barrier layer is It is characterized in that a phosphor lower than that in the fluorescent region is obtained.
【0017】前記構成においては、硫化亜鉛、セレン化
亜鉛、硫化カドミウム及びセレン化カドミウムから選ば
れる少なくとも一つの化合物を含有する化合物半導体を
母体とする蛍光体を、マンガン、マグネシウム、カルシ
ウム、ストロンチウム及びバリウムから選ばれる少なく
とも一つの元素を含有する気体または液体中で熱処理
し、前記蛍光体の表面から所定の深さまで障壁層を形成
することが好ましい。In the above-mentioned structure, a phosphor having a compound semiconductor containing at least one compound selected from zinc sulfide, zinc selenide, cadmium sulfide and cadmium selenide as a matrix is manganese, magnesium, calcium, strontium and barium. It is preferable to perform heat treatment in a gas or liquid containing at least one element selected from the above to form a barrier layer from the surface of the phosphor to a predetermined depth.
【0018】また前記構成においては、母体がY2 O2
Sである蛍光体を、酸素雰囲気中で熱処理し、その表面
から所定の深さまで障壁層を形成することが好ましい。
また前記構成においては、蛍光体粒子にその表面からド
ナーまたはアクセプターを拡散させ、その表面から所定
の深さまで障壁層を形成することが好ましい。Further, in the above structure, the matrix is Y 2 O 2
It is preferable to heat-treat the phosphor that is S in an oxygen atmosphere to form a barrier layer from the surface to a predetermined depth.
Further, in the above structure, it is preferable that the donor or acceptor is diffused from the surface of the phosphor particles to form a barrier layer from the surface to a predetermined depth.
【0019】[0019]
【作用】前記した本発明の構成によれば、蛍光体に電子
ビームを照射すると、以下の作用により従来の蛍光体に
比べて発光効率が向上する。According to the above-mentioned constitution of the present invention, when the phosphor is irradiated with the electron beam, the luminous efficiency is improved as compared with the conventional phosphor by the following effects.
【0020】本発明の蛍光体に、飛程が障壁層厚さより
も長くなる運動エネルギーをもった電子ビームを照射す
ると、障壁層、蛍光領域いずれにおいても2次電子増倍
がおこり多数の電子、正孔が入射電子の軌跡に沿って生
成される。生成される2次電子はホットキャリヤと熱平
衡キャリヤから成る。When the phosphor of the present invention is irradiated with an electron beam having a kinetic energy such that the range is longer than the thickness of the barrier layer, secondary electron multiplication occurs in both the barrier layer and the fluorescent region, and a large number of electrons, Holes are generated along the trajectory of incident electrons. The generated secondary electrons consist of hot carriers and thermal equilibrium carriers.
【0021】そのうち、熱平衡キャリヤはその濃度勾配
に応じて拡散してゆく。障壁層は蛍光領域よりも少なく
とも伝導帯最下端ポテンシャルが高いか、または価電子
帯最上端ポテンシャルが低いので、蛍光領域側の電子、
正孔の少なくともいずれかの熱平衡キャリヤに対して、
蛍光領域−障壁層界面はポテンシャル障壁としてはたら
く。従って蛍光領域側から障壁層中への電子、正孔少な
くとも一方の熱平衡キャリヤの拡散が阻害される。以
降、障壁層の伝導帯最下端ポテンシャルと蛍光領域のそ
れの差をΔεc (障壁層のほうが高い場合を正とす
る。)、また障壁層の価電子帯最上端ポテンシャルと蛍
光領域のそれの差をΔεv (障壁層のほうが低い場合を
正とする。)と表記する。ところで、本発明の蛍光体に
おいても従来の蛍光体同様、障壁層の表面または表面近
傍には多くの非発光中心が存在する。非発光中心濃度は
表面が最も高く、内部になるほど減少する。しかし、本
発明の蛍光体は、非発光中心濃度が表面または表面近傍
に比べて十分少なくなる約1〜100nm程度の深さま
で障壁層で覆われている。また、蛍光領域−障壁層界面
はヘテロ接合が形成されている。つまり、前記界面の非
発光中心濃度は低い。以上より、蛍光領域で生成された
熱平衡キャリヤのうち電子、正孔の少なくともいずれか
一方は、非発光中心濃度の高い表面領域に拡散すること
がないので、蛍光領域で効率よく発光する。Δεc >0
かつΔεv >0の蛍光体の場合は、電子、正孔とも蛍光
領域−障壁層界面がポテンシャル障壁としてはたらき、
それら双方の拡散が界面で阻害されるので一層効果があ
る。また、障壁層厚さは前記のように十分薄いので、V
d は従来の蛍光体に比べて小さい。即ち、発光効率が従
来の蛍光体に比べて向上する。Among them, the heat equilibrium carrier diffuses according to the concentration gradient. Since the barrier layer has a higher potential at the bottom of the conduction band or a lower potential at the top of the valence band than the fluorescent region, electrons on the fluorescent region side,
For at least one thermal equilibrium carrier of holes,
The fluorescent region-barrier layer interface acts as a potential barrier. Therefore, diffusion of thermal equilibrium carriers of at least one of electrons and holes from the fluorescent region side into the barrier layer is hindered. After that, the difference between the bottom edge of the conduction band of the barrier layer and that of the fluorescent region is Δε c (when the barrier layer is higher, it is positive), and the uppermost potential of the valence band of the barrier layer and that of the fluorescent region. The difference is expressed as Δε v (when the barrier layer is lower, it is positive). By the way, in the phosphor of the present invention, like the conventional phosphor, many non-emission centers are present on the surface of the barrier layer or in the vicinity of the surface. The concentration of non-radiative centers is highest on the surface and decreases toward the inside. However, the phosphor of the present invention is covered with the barrier layer to a depth of about 1 to 100 nm at which the concentration of non-emission centers is sufficiently lower than that at the surface or near the surface. A heterojunction is formed at the fluorescent region-barrier layer interface. That is, the concentration of non-radiative centers at the interface is low. As described above, at least one of electrons and holes in the thermal equilibrium carriers generated in the fluorescent region does not diffuse into the surface region where the concentration of non-emission center is high, so that light is efficiently emitted in the fluorescent region. Δε c > 0
In the case of a phosphor having Δε v > 0, both the electron and hole functions as a potential barrier at the fluorescent region-barrier layer interface.
It is more effective because the diffusion of both of them is hindered at the interface. Further, since the barrier layer thickness is sufficiently thin as described above, V
d is smaller than conventional phosphors. That is, the luminous efficiency is improved as compared with the conventional phosphor.
【0022】また本発明の製造方法の構成によれば、前
記本発明の蛍光体を効率良く合理的に製造できる。Further, according to the structure of the manufacturing method of the present invention, the phosphor of the present invention can be manufactured efficiently and rationally.
【0023】[0023]
【実施例】以下実施例を用いて本発明をさらに具体的に
説明する。図2は、CFPにおける発光輝度の加速電圧
依存性を測定したデータである。Bが従来の蛍光体を用
いたときの測定結果である。この測定結果をもとに、C
FPにおける発光効率−加速電圧特性をグラフ化したも
のを図3に示す。同じく、Bが従来の蛍光体を用いた場
合である。EXAMPLES The present invention will be described in more detail with reference to the following examples. FIG. 2 shows data obtained by measuring the dependence of the emission luminance of CFP on the acceleration voltage. B is a measurement result when a conventional phosphor is used. Based on this measurement result, C
FIG. 3 shows a graph of the luminous efficiency-accelerating voltage characteristics in FP. Similarly, B is a case where a conventional phosphor is used.
【0024】一般に蛍光体は加速電圧Vが低くなればな
るほど発光効率が低くなる性質がある。これが、CFP
での発光効率ηがCRTでのそれより低くなる原因であ
る。図4に、導電性基板上に蛍光体を置き、その上から
電子ビームを照射したときの蛍光体の輝度−加速電圧特
性を示す。この測定ではメタルバックは設けていない。
Bが従来の蛍光体を用いたときの測定結果である。この
測定結果をもとに、蛍光体の発光効率−加速電圧特性を
グラフ化したものを図5に示す。Generally, the phosphor has a property that the lower the accelerating voltage V, the lower the luminous efficiency. This is CFP
This is the reason why the luminous efficiency η in CRT is lower than that in CRT. FIG. 4 shows the luminance-acceleration voltage characteristics of the phosphor when the phosphor is placed on the conductive substrate and the electron beam is irradiated from above. No metal back was provided in this measurement.
B is a measurement result when a conventional phosphor is used. FIG. 5 shows a graph of the luminous efficiency-accelerating voltage characteristics of the phosphor based on the measurement results.
【0025】図5に示される、加速電圧の低下に伴って
発光効率が減少するという性質は、蛍光体の表面または
表面近傍の非発光中心の存在に起因していると考えられ
ている。図4に示されるように、2〜3kV程度以下の
加速電圧では蛍光体は殆ど発光しないという現象がその
ことを示している。加速電圧がVd 以下では発光しな
い。Vd は一般にはデッドボルテージと呼ばれている。It is considered that the property shown in FIG. 5 that the luminous efficiency decreases with a decrease in accelerating voltage is due to the presence of non-emissive centers on or near the surface of the phosphor. As shown in FIG. 4, the phenomenon that the phosphor hardly emits light at an accelerating voltage of about 2 to 3 kV or less is shown. It does not emit light when the acceleration voltage is V d or less. V d is generally called dead voltage.
【0026】蛍光体の上記性質の成因はつぎのように考
えられる。蛍光体中に打ち込まれた電子ビームは、蛍光
体中で散乱を繰り返しながら減速されてゆく。高速の電
子は構成原子との非弾性散乱の度に蛍光体を励起し新た
なホットキャリヤを生成してゆく。それらが再び蛍光体
を励起しさらにキャリヤを生成する。このような固体内
の2次電子増倍は、電子の運動エネルギーがイオン化し
きい値エネルギーより低くなるまで繰り返される。以上
の過程により生成された多数の熱平衡キャリヤ(電子、
正孔)が拡散してゆく過程で発光中心にトラップされ、
再結合し発光する。The cause of the above properties of the phosphor is considered as follows. The electron beam injected into the phosphor is decelerated while repeatedly scattering in the phosphor. High-speed electrons excite the phosphor and generate new hot carriers each time they are inelastically scattered with the constituent atoms. They excite the phosphor again and generate more carriers. Such secondary electron multiplication in the solid is repeated until the kinetic energy of electrons becomes lower than the ionization threshold energy. Many thermal equilibrium carriers (electrons,
(Holes) are trapped in the emission center in the process of diffusion,
Recombines and emits light.
【0027】一方、電子ビームが蛍光体に入射するとき
の浸入深さはその加速電圧が低くなるにつれて浅くな
る。例えばZnSを母体とする蛍光体の場合、加速電圧
が10kVであれば浸入深さは約1.5μmであるの
に、2.5kVでは浸入深さは約100nmと非常に浅
くなる。蛍光体の表面または表面近傍には表面準位また
は格子欠陥などの非発光中心が多数存在する。加速電圧
が低いと電子ビームは蛍光体内部深くまでは浸入せず、
生成される電子、正孔は表面、または表面近傍の非発光
中心の多い場所に限られるため、それらにトラップされ
て発光することなく再結合してしまう。従って、ある加
速電圧(Vd )以下では蛍光体は発光しない。加速電圧
が高い場合でも、生成されるキャリヤのうち表面近傍で
生成されたものは同様に非輻射的に再結合してしまう。
熱平衡キャリヤの拡散距離Lは例えばZnS:Agでは
L=0.1μm程度なので、表面からの深さが0.1μ
m程度以下の場所で生成された熱平衡キャリヤは容易に
蛍光体表面近傍まで拡散し、非発光中心にトラップされ
てしまう。以上のメカニズムにより図4のような輝度−
加速電圧特性が得られるものと考えられる。その結果、
図5のような発光効率−加速電圧特性となる。On the other hand, the penetration depth when the electron beam enters the phosphor becomes shallower as the acceleration voltage becomes lower. For example, in the case of a phosphor having ZnS as a matrix, the penetration depth is about 1.5 μm at an acceleration voltage of 10 kV, but at 2.5 kV, the penetration depth is about 100 nm, which is very shallow. Many non-emission centers such as surface states or lattice defects exist on or near the surface of the phosphor. When the accelerating voltage is low, the electron beam does not penetrate deep inside the phosphor,
Since the generated electrons and holes are limited to the surface or a place near the surface where there are many non-emissive centers, they are trapped by these and recombine without emitting light. Therefore, the phosphor does not emit light below a certain acceleration voltage (V d ). Even when the accelerating voltage is high, carriers generated near the surface also recombine non-radiatively.
The diffusion distance L of the thermal equilibrium carrier is about 0.1 μm for ZnS: Ag, so the depth from the surface is 0.1 μm.
The thermal equilibrium carriers generated in the place of about m or less easily diffuse to the vicinity of the surface of the phosphor and are trapped in the non-radiative center. Due to the above mechanism, the brightness as shown in FIG.
It is considered that acceleration voltage characteristics can be obtained. as a result,
The light emission efficiency-accelerating voltage characteristic shown in FIG. 5 is obtained.
【0028】図2と図4を比較すると、Vd が異なる。
蛍光体の輝度−加速電圧特性に比べてCFPでそれを発
光させたときの方が見かけ上Vd が大きい。これは、C
FPでは、蛍光体層に入射電子が到達する前にメタルバ
ックを透過し、その際運動エネルギーの一部を失うため
である。その分CFPの方が見かけ上Vd が増える。Comparing FIG. 2 and FIG. 4, V d is different.
Apparently, V d is larger when the phosphor is made to emit light by CFP, as compared with the luminance-accelerating voltage characteristic of the phosphor. This is C
This is because in the FP, the incident electrons pass through the metal back before reaching the phosphor layer and lose part of the kinetic energy at that time. The CFP apparently increases V d accordingly .
【0029】(実施例1)図1は実施例1の蛍光体の断
面図である。蛍光領域1の表面を障壁層2が覆ってい
る。本実施例では蛍光領域1には粒径が数μm〜10数
μmのZnS:Agを用い、障壁層2には厚さが約10
〜30nmのZn0.8 Mg0.2 Sを用いた。Example 1 FIG. 1 is a sectional view of the phosphor of Example 1. The barrier layer 2 covers the surface of the fluorescent region 1. In this embodiment, ZnS: Ag having a particle size of several μm to several tens of μm is used for the fluorescent region 1, and the barrier layer 2 has a thickness of about 10 μm.
Zn 0.8 Mg 0.2 S of ˜30 nm was used.
【0030】図4のAが、本実施例の蛍光体に対して、
発光輝度−加速電圧特性を測定した結果である。明るい
青色の発光が得られた。Vd は1kV程度と従来の蛍光
体Bに比べて低減できた。この測定結果をもとに、本実
施例の蛍光体の発光効率−加速電圧特性をグラフ化した
ものが図5のAである。従来の蛍光体Bに比べて発光効
率が向上した。これは、デッドボルテージVd の低減に
よる効果であると考えられる。この蛍光体をCFPで使
用したときの発光輝度の加速電圧依存性を測定したデー
タが図2に示したAである。Vd =約3kVと従来の蛍
光体BをCFPで発光させた場合のVd (約4.5k
V)に比べて低減できた。この測定結果をもとに、本実
施例の蛍光体AをCFPで使用したときの発光効率−加
速電圧特性が図3に示したAである。FIG. 4A shows the case of the phosphor of the present embodiment.
It is a result of measuring emission luminance-accelerating voltage characteristics. A bright blue emission was obtained. V d could reduced compared to 1kV about the conventional phosphor B. FIG. 5A is a graph showing the luminous efficiency-accelerating voltage characteristics of the phosphor of this example based on the measurement results. The luminous efficiency was improved as compared with the conventional phosphor B. This is considered to be the effect of reducing the dead voltage V d . The data obtained by measuring the dependence of the emission luminance on the acceleration voltage when this phosphor is used in CFP is A shown in FIG. V d = about 3kV and when the conventional phosphor B emit light with CFP V d (approximately 4.5k
It was possible to reduce compared to V). Based on these measurement results, the emission efficiency-accelerating voltage characteristic when the phosphor A of this example was used in CFP is A shown in FIG.
【0031】本実施例の蛍光体は、CRT、CFPいず
れに対しても発光効率ηを向上させる効果があったが、
特にCFPに対して大きな効果があった。本実施例の蛍
光体をCFPで発光させた場合、加速電圧V=10kV
の時の発光効率ηは約16%と従来の蛍光体Bに比べて
約30%向上した。このような発光効率改善効果は、加
速電圧がより低い場合いっそう顕著であった。例えば、
V=7kVの時、従来の蛍光体Bを用いたのではη=約
7%しか得られなかったのに対して、本実施例の蛍光体
を用いたところη=約13%と約80%も発光効率が改
善された。一方、従来10kV程度の加速電圧で駆動し
ていたものを、約6kVで駆動しても従来同等の発光効
率を得ることができた。従来のCFPに比べ低加速電圧
駆動ができたため、放電が起こりにくくなった。その結
果、その奥行きを従来よりさらに薄くすることができる
ようになった。The phosphor of this example had the effect of improving the luminous efficiency η for both CRT and CFP.
In particular, it had a great effect on CFP. When the phosphor of this example is caused to emit light by CFP, the acceleration voltage V = 10 kV
At that time, the luminous efficiency η was about 16%, which was about 30% higher than that of the conventional phosphor B. The effect of improving the luminous efficiency was more remarkable when the acceleration voltage was lower. For example,
When V = 7 kV, η = about 7% was obtained using the conventional phosphor B, whereas η = about 13% and about 80% when using the phosphor of this example. The luminous efficiency was also improved. On the other hand, it was possible to obtain the same luminous efficiency as that of the prior art, even if it was driven at an accelerating voltage of about 10 kV in the related art, but at about 6 kV. Since it was possible to drive at an acceleration voltage lower than that of the conventional CFP, discharge did not easily occur. As a result, the depth can be made thinner than before.
【0032】本実施例の蛍光体で発光効率が向上した理
由は以下のように考えられる。本実施例の蛍光体の障壁
層2の厚さは約10〜30nmなので、約0.7〜1.
2keV程度以上に加速された電子ビームの飛程は障壁
層2を越えて蛍光領域1に及ぶ。障壁層、蛍光領域いず
れにおいても2次電子増倍がおこり多数の電子、正孔が
入射電子の軌跡に沿って生成される。生成される2次電
子はホットキャリヤと熱平衡キャリヤから成る。The reason why the luminous efficiency of the phosphor of this example is improved is considered as follows. Since the barrier layer 2 of the phosphor of this embodiment has a thickness of about 10 to 30 nm, it has a thickness of about 0.7 to 1.
The range of the electron beam accelerated to about 2 keV or more reaches the fluorescent region 1 beyond the barrier layer 2. Secondary electron multiplication occurs in both the barrier layer and the fluorescent region, and a large number of electrons and holes are generated along the trajectory of incident electrons. The generated secondary electrons consist of hot carriers and thermal equilibrium carriers.
【0033】本実施例では障壁層材料としてZn0.8 M
g0.2 Sを用いた。この3元化合物半導体材料は蛍光領
域の母体のZnSよりもバンドギャップが広い。また、
その伝導帯最下端ポテンシャルはZnSよりも浅く、か
つ価電子帯最上端ポテンシャルはZnSより低い。即
ち、Δεc >0かつΔεv >0である。従って、熱平衡
キャリヤ(電子、正孔)いずれにとっても、蛍光領域1
と障壁層2の界面はポテンシャル障壁としてはたらく。
従って、前記熱平衡キャリヤはその濃度勾配に応じて拡
散してゆくものの、蛍光領域側から障壁層中へのそれら
の拡散は阻害される。また、障壁層を構成するZn0.8
Mg0.2 Sは蛍光領域のZnSと同じ閃亜鉛鉱型結晶構
造をとる。格子定数は後者のほうが若干大きいものの、
その厚さは約10〜20nmと十分薄いので、それが原
因で障壁層中に転位が導入されることはない。従って、
両者の界面は良好なヘテロ接合を形成している。非発光
中心濃度は表面が最も高く、内部になるほど減少し、前
記界面あたりでは表面に比べて低い。以上より、蛍光領
域で生成された熱平衡キャリヤは、非発光中心濃度の高
い表面領域に拡散することがないので、蛍光領域で効率
よく発光する。以上のメカニズムにより本実施例の蛍光
体の発光効率は従来のものに比べて高まったと考えられ
る。In this embodiment, the barrier layer material is Zn 0.8 M.
g 0.2 S was used. This ternary compound semiconductor material has a wider band gap than ZnS, which is the matrix of the fluorescent region. Also,
The conduction band bottom end potential is shallower than ZnS, and the valence band top end potential is lower than ZnS. That is, Δε c > 0 and Δε v > 0. Therefore, the fluorescent region 1 is not affected by any of the heat balance carriers (electrons, holes).
The interface between the barrier layer 2 and the barrier layer 2 functions as a potential barrier.
Therefore, the thermal equilibrium carriers diffuse according to the concentration gradient, but their diffusion from the fluorescent region side into the barrier layer is hindered. In addition, Zn 0.8 which constitutes the barrier layer
Mg 0.2 S has the same zinc blende type crystal structure as ZnS in the fluorescent region. The latter has a slightly larger lattice constant,
Its thickness is as thin as about 10 to 20 nm, so that dislocations are not introduced into the barrier layer due to it. Therefore,
The interface between the two forms a good heterojunction. The concentration of non-radiative centers is highest on the surface, decreases toward the inside, and is lower around the interface than on the surface. As described above, the thermal equilibrium carriers generated in the fluorescent region do not diffuse into the surface region where the concentration of non-emission centers is high, so that the light efficiently emits in the fluorescent region. It is considered that the emission efficiency of the phosphor of this example is higher than that of the conventional one by the above mechanism.
【0034】所定の範囲内で前記障壁層におけるMgの
組成比を高くすると、さらにVd を低減させることがで
きた。これは、Mg組成比の増加に伴い、よりバンドギ
ャップが大きくなった、特にΔεc が大きくなったこと
による効果と考えてよい。By increasing the composition ratio of Mg in the barrier layer within the predetermined range, V d could be further reduced. This can be considered to be an effect due to a larger band gap, in particular, a larger Δε c as the Mg composition ratio increases.
【0035】障壁層材料に適当なドナー、またはアクセ
プター不純物をドープすることで、Δεc およびΔεv
をある程度制御することができる。上記実施例では障壁
層のZn0.8 Mg0.2 Sにドナー、またはアクセプター
不純物はドープしていない例を示したが、例えば、障壁
層にドナー不純物のClを適量ドープすることで、Δε
c は減少するものの、逆にΔεv は増大し、より蛍光領
域の正孔の障壁層への拡散を阻害することができる。By doping the barrier layer material with appropriate donor or acceptor impurities, Δε c and Δε v
Can be controlled to some extent. In the above embodiment, Zn 0.8 Mg 0.2 S of the barrier layer is not doped with a donor or acceptor impurity. However, for example, by doping the barrier layer with an appropriate amount of donor impurity Cl, Δε
Although c decreases, Δε v increases on the contrary, and diffusion of holes in the fluorescent region into the barrier layer can be further hindered.
【0036】一方、蛍光領域1に粒径が数μm〜10数
μmのZnS0.5 Se0.5 :Agを用い、障壁層2には
厚さが約10〜30nmのZn0.9 Mg0.1 S0.9 Se
0.1を用いても、上記実施例同様、従来の蛍光体に比べ
て発光効率が向上した。明るい緑色に発光した。また、
蛍光領域1にZn0.7 Cd0.3 S:Agを用い、障壁層
2にはZn0.9 Mg0.1 S0.9 Se0.1 を用いても、同
様の効果が得られた。On the other hand, ZnS 0.5 Se 0.5 : Ag having a particle size of several μm to several tens of μm is used for the fluorescent region 1, and Zn 0.9 Mg 0.1 S 0.9 Se having a thickness of about 10 to 30 nm is used for the barrier layer 2.
Even when 0.1 was used, the luminous efficiency was improved as compared with the conventional phosphor, as in the above-mentioned example. It emitted a bright green color. Also,
The same effect was obtained by using Zn 0.7 Cd 0.3 S: Ag for the fluorescent region 1 and Zn 0.9 Mg 0.1 S 0.9 Se 0.1 for the barrier layer 2.
【0037】また、障壁層材料としてMgのかわりにM
nが所定の組成で混ざった化合物半導体を用いてもよ
い。例えば、上記実施例において障壁層材料としてZn
0.9 Mn0.1 S0.9 Se0.1 を用いてもよい。Also, instead of Mg as the barrier layer material, M
A compound semiconductor in which n has a predetermined composition may be used. For example, Zn is used as the barrier layer material in the above embodiment.
0.9 Mn 0.1 S 0.9 Se 0.1 may be used.
【0038】蛍光領域及び障壁層を構成する材料とし
て、硫化亜鉛、セレン化亜鉛、硫化カドミウム、セレン
化カドミウム、またはそれらの混晶の組合せを用いても
よい。例えば、蛍光領域にZn0.7 Cd0.3 S:Ag
を、障壁層材料にそれよりバンドギャップの大きなZn
Sを用いても同様の効果が得られた。また上記のII-VI
族化合物半導体にカルシウムまたはストロンチウムまた
はバリウムが含有した混晶半導体を用いることもでき
る。As a material for forming the fluorescent region and the barrier layer, zinc sulfide, zinc selenide, cadmium sulfide, cadmium selenide, or a mixed crystal thereof may be used. For example, Zn 0.7 Cd 0.3 S: Ag in the fluorescent region
The barrier layer material is Zn, which has a larger bandgap.
The same effect was obtained by using S. Also II-VI above
A mixed crystal semiconductor containing calcium, strontium, or barium can be used as the group compound semiconductor.
【0039】(実施例2)蛍光領域及び障壁層を構成す
る材料として、Y2 O3 、Y2 O2 S、または少なくと
もこれらの化合物のいずれかを含有する化合物半導体を
用いてもよい。蛍光領域1に粒径が数μm〜10数μm
のY2 O2 S:Eu3+を用い、障壁層2には厚さがY2
O3 を用いたところ、実施例1と同様、従来の蛍光体に
比べて発光効率が向上した。明るい赤色に発光した。Y
2 O2 Sの方がY2 O3 よりバンドギャップが小さく、
Δεc >0かつΔεv >0となる。そのことが効果を出
現させたと考えられる。Example 2 As a material for forming the fluorescent region and the barrier layer, Y 2 O 3 , Y 2 O 2 S, or a compound semiconductor containing at least one of these compounds may be used. Particle size of several μm to several tens of μm in the fluorescent region 1
Y 2 O 2 S: Eu 3+ is used, and the barrier layer 2 has a thickness of Y 2
When O 3 was used, the luminous efficiency was improved as compared with the conventional phosphor, as in Example 1. It emitted a bright red color. Y
2 O 2 S has a smaller band gap than Y 2 O 3 ,
Δε c > 0 and Δε v > 0. It is considered that this has brought about the effect.
【0040】以上の実施例は、蛍光領域−障壁層界面が
急峻な場合を説明したが、少なくとも伝導帯最下端ポテ
ンシャルが表面に近づくにつれて徐々に浅くなる、また
は前記障壁層の価電子帯最上端ポテンシャルが表面に近
づくにつれて徐々に深くなるバンド構造を有する障壁層
を用いてもよい。蛍光領域がZnS:Agであって、障
壁層がZn1-x Mgx Sで表面に近づくにつれてxが大
きくなる組成分布をもった構造の蛍光体も前記実施例同
様の効果が得られた。In the above embodiments, the case where the fluorescent region-barrier layer interface is steep is explained. However, at least the conduction band bottom end potential gradually becomes shallower as it approaches the surface, or the barrier layer top end of the valence band of the barrier layer. A barrier layer having a band structure in which the potential becomes deeper as the potential approaches the surface may be used. The same effect as in the above example was obtained with a phosphor having a structure in which the fluorescent region was ZnS: Ag and the barrier layer was Zn 1-x Mg x S having a composition distribution in which x increased as the surface approached the surface.
【0041】(実施例3)本実施例は、蛍光領域と障壁
層でその母体は同じであるが、ドープされている不純物
の種類またはその濃度が異なる場合である。蛍光領域に
はZnS:Cu、Alを用い、障壁層にはZnS:Cu
を用いたところ、上記同様の効果がみられた。この場
合、障壁層の方が蛍光領域に比べてドナー濃度が低いの
で、両者の間に拡散電位があらわれ、電子に対するポテ
ンシャルバリヤΔεc (>0)が生じたためと考えられ
る。なお本実施例の効果は、障壁層の厚さを1〜100
nm程度の範囲に設定したとき、良く現れた。(Embodiment 3) In the present embodiment, the fluorescent region and the barrier layer have the same base material, but the type or concentration of doped impurities are different. ZnS: Cu and Al are used for the fluorescent region and ZnS: Cu is used for the barrier layer.
When using, the same effect as above was observed. In this case, it is considered that since the barrier layer has a lower donor concentration than the fluorescent region, a diffusion potential appears between the barrier layer and the potential barrier Δε c (> 0) for electrons. The effect of this embodiment is that the thickness of the barrier layer is set to 1 to 100.
It appeared well when set in the range of about nm.
【0042】(実施例4)次に本実施例の蛍光体の製造
方法の例を説明する。典型的には0.01〜0.5mo
l/lの硫酸亜鉛(ZnSO4 )水溶液と、0.01〜
0.5mol/lの硫酸マグネシウム(MgSO4 )水
溶液と、0.1〜1mol/lのチオ尿素((H2 N)
2 CS)水溶液と、0.1〜1mol/lの水酸化ナト
リウム(NaOH)水溶液とを所定の比率で混合した溶
液中に、直径が数μm〜10数μmのZnS:Agより
なる蛍光体粒子を入れ、その液温を50〜80℃(0〜
100℃の範囲で実施できる。)程度に保って、撹拌し
ながら数分間反応させたところ、前記蛍光体粒子の表面
に厚さが10〜30nm程度のZn1-x Mgx S層を成
長させることができた。この層は前記蛍光体粒子を核と
してエピタキシャル成長した。高い結晶性の層が得られ
た。(Embodiment 4) Next, an example of a method for manufacturing the phosphor of this embodiment will be described. Typically 0.01-0.5 mo
1 / l zinc sulfate (ZnSO 4 ) aqueous solution, and 0.01-
0.5 mol / l magnesium sulfate (MgSO 4 ) aqueous solution and 0.1 to 1 mol / l thiourea ((H 2 N))
2 CS) aqueous solution and 0.1 to 1 mol / l sodium hydroxide (NaOH) aqueous solution mixed in a predetermined ratio, and phosphor particles made of ZnS: Ag having a diameter of several μm to several dozen μm. , And the liquid temperature at 50-80 ° C (0-
It can be carried out in the range of 100 ° C. When the reaction is carried out for several minutes while stirring, the Zn 1-x Mg x S layer having a thickness of about 10 to 30 nm can be grown on the surface of the phosphor particles. This layer was epitaxially grown using the phosphor particles as nuclei. A highly crystalline layer was obtained.
【0043】以上の方法で作製した本実施例の蛍光体を
電子ビームで励起し、その特性を評価したところ、前記
実施例同様、発光効率が従来の蛍光体に比べて向上し
た。その効果は、特に15kV程度以下の低加速電圧域
で顕著であった。When the phosphor of this example manufactured by the above method was excited by an electron beam and its characteristics were evaluated, the luminous efficiency was improved as compared with the conventional phosphor, as in the above example. The effect was particularly remarkable in the low acceleration voltage region of about 15 kV or less.
【0044】Zn1-x Mgx S層が本実施例の蛍光体に
おける障壁層として、またZnS:Ag粒子が同蛍光領
域として機能したと考えられる。本実施例の製造方法を
用いることで、容易に低コストで本実施例の蛍光体を作
製することができた。It is considered that the Zn 1-x Mg x S layer functioned as a barrier layer in the phosphor of this example, and the ZnS: Ag particles functioned as the same fluorescent region. By using the manufacturing method of this example, the phosphor of this example could be easily manufactured at low cost.
【0045】障壁層を構成するZn1-x Mgx Sの組成
比xは、前記硫酸亜鉛水溶液、硫酸マグネシウム水溶
液、チオ尿素水溶液の混合比を変えることで制御でき
た。一方、前記溶液中に含まれるイオンの種類を変えて
やることで、成長させる障壁層の構成材料を変えること
ができる。例えば、それぞれ所定の濃度の硫酸亜鉛水溶
液と、硫酸マンガン水溶液と、チオ尿素水溶液と、水酸
化ナトリウム水溶液の混合溶液中に前記蛍光体粒子を入
れたところ、前記蛍光体粒子の表面に厚さが10〜30
nm程度のZn1-x Mnx S層を成長させることができ
た。この蛍光体も前記実施例同様の効果を得ることがで
きた。The composition ratio x of Zn 1-x Mg x S forming the barrier layer can be controlled by changing the mixing ratio of the zinc sulfate aqueous solution, the magnesium sulfate aqueous solution and the thiourea aqueous solution. On the other hand, the constituent material of the barrier layer to be grown can be changed by changing the type of ions contained in the solution. For example, when the phosphor particles are placed in a mixed solution of a zinc sulfate aqueous solution, a manganese sulfate aqueous solution, a thiourea aqueous solution, and a sodium hydroxide aqueous solution, each having a predetermined concentration, the surface of the phosphor particles has a thickness. 10-30
It was possible to grow a Zn 1-x Mn x S layer of about nm. This phosphor was also able to obtain the same effect as in the above-mentioned embodiment.
【0046】(実施例5)次に本発明の蛍光体の別の製
造方法の例を説明する。本実施例の蛍光体は、下記の様
な気相エピタキシャル成長法を用いても作製することが
できた。成長装置には一般的な常圧MOCVD装置を用
いた。グラファイト製のサセプタ上に直径が数μm〜1
0数μmのZnS:Cuよりなる蛍光体粒子を薄く並
べ、これを約450℃に加熱し、ジメチル亜鉛とビスシ
クロペンタジエニルマグネシウムとジエチル硫黄を適当
な混合比で導入し、前記蛍光体表面に障壁層を成長させ
た。成長中、前記蛍光体粒子をサセプタ上で頻繁に転が
し、できるだけ成長する障壁層の厚さが均一になるよう
に注意した。前記蛍光体粒子の表面に厚さが10〜30
nm程度のZn1-x Mgx Sよりなる障壁層をエピタキ
シャル成長させることができた。得られた蛍光体も前記
実施例同様の効果を得ることができた。Example 5 Next, an example of another method for producing the phosphor of the present invention will be described. The phosphor of this example could also be manufactured by using the vapor phase epitaxial growth method as described below. A general atmospheric pressure MOCVD apparatus was used as the growth apparatus. The diameter is several μm to 1 on the graphite susceptor.
Phosphor particles made of ZnS: Cu with a thickness of 0 to several μm are thinly arranged, heated to about 450 ° C., and dimethylzinc, biscyclopentadienylmagnesium and diethylsulfur are introduced at an appropriate mixing ratio, and the phosphor surface A barrier layer was grown on. During the growth, the phosphor particles were frequently rolled on the susceptor, and care was taken to make the thickness of the growing barrier layer as uniform as possible. The surface of the phosphor particles has a thickness of 10 to 30.
It was possible to epitaxially grow a barrier layer of Zn 1-x Mg x S of about nm. The obtained phosphor was also able to obtain the same effects as in the above-mentioned example.
【0047】障壁層を構成するZn1-x Mgx Sの組成
比xは、前記のジメチル亜鉛とビスシクロペンタジエニ
ルマグネシウムとジエチル硫黄の流量比を変えることで
容易に制御できた。また、導入するガスの種類を変えれ
ば、容易に障壁層の構成材料を変えることができる。成
長方法として他にも減圧MOCVD法や気相輸送法等の
熱CVD法を用いてもよい。但し、いずれの方法におい
ても概ね250〜700℃程度の成長温度で成長させた
場合の結果が良好であった。これは、成長温度が低すぎ
ると高い結晶性の障壁層が得られず、また逆に高すぎる
と蛍光領域と障壁層の構成元素が相互拡散しポテンシャ
ル障壁が形成できないことによるのではないかと考えら
れる。The composition ratio x of Zn 1-x Mg x S constituting the barrier layer could be easily controlled by changing the flow rate ratio of dimethyl zinc, biscyclopentadienyl magnesium and diethyl sulfur. Further, the constituent material of the barrier layer can be easily changed by changing the type of gas to be introduced. Alternatively, a thermal CVD method such as a low pressure MOCVD method or a vapor transport method may be used as the growth method. However, in any method, the result when the growth was performed at the growth temperature of about 250 to 700 ° C. was good. This is probably because if the growth temperature is too low, a highly crystalline barrier layer cannot be obtained, and conversely, if it is too high, the constituent elements of the fluorescent region and the barrier layer interdiffuse and a potential barrier cannot be formed. To be
【0048】(実施例6)次に本発明の蛍光体のさらに
別の製造方法の例を説明する。石英管中に設置した基板
上に直径が数μm〜10数μmのZnS:Cu、Alよ
りなる蛍光体粒子を置き、これを概ね700℃に加熱
し、ビスシクロペンタジエニルマグネシウムと窒素を適
当な混合比で導入し、約10分間加熱したところ、前記
ZnS:Ag、Clの表面からMgが拡散し、表面から
約30nm程度以内の領域がZn1-xMgx S:Ag、
Cl層となった。本実施例の蛍光体も前記実施例同様の
効果を得ることができた。(Embodiment 6) Next, another example of a method for producing the phosphor of the present invention will be described. Phosphor particles made of ZnS: Cu, Al having a diameter of several μm to several tens of μm are placed on a substrate placed in a quartz tube and heated to about 700 ° C., and biscyclopentadienyl magnesium and nitrogen are appropriately added. When the mixture was introduced at a different mixing ratio and heated for about 10 minutes, Mg diffused from the surface of the ZnS: Ag, Cl, and a region within about 30 nm from the surface was Zn 1-x Mg x S: Ag,
It became a Cl layer. The phosphor of this example was also able to obtain the same effect as that of the above example.
【0049】(実施例7)次に本発明の蛍光体のさらに
別の製造方法の例を説明する。石英製るつぼに塩化マグ
ネシウムを入れ、加熱、溶融させた。その中へ直径が数
μm〜10数μmのZnS:Ag、Clよりなる蛍光体
粒子を入れ、かくはんしながら約10分間作用させた。
その後、室温にまで冷却後、固化した混合物を水洗して
塩化マグネシウムを除去した。得られた蛍光体の表面に
はMg、Clの拡散によりZn1-xMgx S:Ag、C
lよりなる厚さ約10〜30nmの障壁層が形成され
た。本実施例の蛍光体も前記実施例同様の効果を得るこ
とができた。(Embodiment 7) Next, an example of still another method for producing the phosphor of the present invention will be described. Magnesium chloride was placed in a quartz crucible and heated and melted. Phosphor particles made of ZnS: Ag, Cl having a diameter of several μm to several tens of μm were put therein and allowed to act for about 10 minutes while stirring.
Then, after cooling to room temperature, the solidified mixture was washed with water to remove magnesium chloride. Zn 1-x Mg x S: Ag, C is formed on the surface of the obtained phosphor by diffusion of Mg and Cl.
A barrier layer having a thickness of about 10 to 30 nm composed of 1 was formed. The phosphor of this example was also able to obtain the same effect as that of the above example.
【0050】次に本発明の蛍光体の製造方法の第5実施
例を説明する。直径が数μm〜10数μmのY2 O
2 S:Eu3+よりなる蛍光体粒子を磁製るつぼに入れ、
約800℃に加熱し、そこへ酸素を導入し約10分間焼
成した。その結果、前記Y2 O2S:Eu3+の表面から
約30nm程度以内の領域が酸化され、Y2 O3 :Eu
3+となった。本実施例の蛍光体も前記実施例同様の効果
を得ることができた。Next, a fifth embodiment of the phosphor manufacturing method of the present invention will be described. Y 2 O with a diameter of a few μm to a few μm
2 Put S: Eu 3+ phosphor particles in a porcelain crucible,
It was heated to about 800 ° C., oxygen was introduced therein, and it was baked for about 10 minutes. As a result, a region within about 30 nm from the surface of the Y 2 O 2 S: Eu 3+ is oxidized and Y 2 O 3 : Eu
It became 3+ . The phosphor of this example was also able to obtain the same effect as that of the above example.
【0051】(実施例8)次に本発明の蛍光体のさらに
別の製造方法の例を説明する。石英管中に設置した基板
上に直径が数μm〜10数μmのZnS:Cu、Alよ
りなる蛍光体粒子を置き、これを約700℃に加熱し、
そこへ硫酸銅水溶液を窒素ガスでバブリングしたドーピ
ングガスを導入した。約10間加熱したところ、前記Z
nS:Cu、Alの表面から30nm程度以内の領域の
Cuの濃度が内部に比べて高まった。本実施例の蛍光体
も前記実施例同様の効果を得ることができた。本実施例
の蛍光体は、前記のCu濃度の高い領域が障壁層として
はたらいたと考えられる。即ち、前記領域は内部に比べ
てアクセプタ濃度が高いので、両者の間に拡散電位が現
れ、電子に対するポテンシャルバリヤΔεc (>0)が
生じたと考えられる。(Embodiment 8) Next, an example of still another method for producing the phosphor of the present invention will be described. Phosphor particles made of ZnS: Cu, Al having a diameter of several μm to several tens of μm are placed on a substrate placed in a quartz tube and heated to about 700 ° C.,
A doping gas obtained by bubbling a copper sulfate aqueous solution with nitrogen gas was introduced therein. After heating for about 10 minutes, Z
The concentration of Cu in a region within about 30 nm from the surface of nS: Cu, Al was higher than that in the inside. The phosphor of this example was also able to obtain the same effect as that of the above example. It is considered that in the phosphor of this example, the above-described region having a high Cu concentration acted as a barrier layer. That is, it is considered that since the region has a higher acceptor concentration than the inside, a diffusion potential appears between them and a potential barrier Δε c (> 0) for electrons occurs.
【0052】[0052]
【発明の効果】本発明により、低コストで容易に蛍光体
の発光効率を向上させることができた。その結果、入力
パワーを上げることなくCRTやCFPの輝度を高める
ことができた。特にCFPのように、約15kV程度以
下の低加速電圧領域で動作させる場合、その発光効率を
大幅に向上させることができた。また、CFPにおける
加速電圧を従来に比べて大幅に低減することができた。
その結果、CFPの奥行きを従来に比べ大幅に薄くする
ことができた。また、電子ビームの偏向電圧も低減でき
た。According to the present invention, the luminous efficiency of the phosphor can be easily improved at low cost. As a result, the brightness of the CRT or CFP could be increased without increasing the input power. In particular, when operating in a low acceleration voltage region of about 15 kV or less like CFP, the luminous efficiency could be significantly improved. Moreover, the acceleration voltage in CFP was able to be reduced significantly compared with the past.
As a result, the depth of the CFP could be made significantly thinner than before. Also, the deflection voltage of the electron beam could be reduced.
【図1】本発明の一実施例の蛍光体の断面図である。FIG. 1 is a sectional view of a phosphor according to an embodiment of the present invention.
【図2】本発明の一実施例の蛍光体及び従来の蛍光体を
CFPで用いたときの、発光輝度−加速電圧特性の測定
結果である。FIG. 2 is a measurement result of emission luminance-accelerating voltage characteristics when the phosphor of one example of the present invention and the conventional phosphor are used in CFP.
【図3】本発明の一実施例の蛍光体及び従来の蛍光体を
CFPで用いたときの、発光輝度−加速電圧特性より得
られたCFPの発光効率−加速電圧特性である。FIG. 3 is a luminous efficiency-acceleration voltage characteristic of CFP obtained from an emission luminance-acceleration voltage characteristic when the phosphor of one example of the present invention and a conventional phosphor are used in CFP.
【図4】本発明の一実施例の蛍光体及び従来の蛍光体の
発光輝度−加速電圧特性の測定結果である。FIG. 4 shows measurement results of emission luminance-accelerating voltage characteristics of the phosphor of one example of the present invention and the conventional phosphor.
【図5】本発明の一実施例の蛍光体及び従来の蛍光体の
発光輝度−加速電圧特性より得られた蛍光体の発光効率
−加速電圧特性である。FIG. 5 shows emission efficiency-acceleration voltage characteristics of a phosphor obtained from emission luminance-acceleration voltage characteristics of a phosphor of an example of the present invention and a conventional phosphor.
【図6】CFPの従来例の断面図である。FIG. 6 is a cross-sectional view of a conventional example of CFP.
【図7】CFPの従来例における蛍光スクリーンの断面
図である。FIG. 7 is a cross-sectional view of a fluorescent screen in a conventional CFP example.
1 蛍光領域 2 障壁層 54 蛍光スクリーン 56 蛍光体層 57 メタルバック 1 Fluorescent Area 2 Barrier Layer 54 Fluorescent Screen 56 Fluorescent Material Layer 57 Metal Back
Claims (13)
してその表面を覆う障壁層を備え、少なくとも前記障壁
層の伝導帯最下端ポテンシャルが前記蛍光領域のそれよ
り高いか、または前記障壁層の価電子帯最上端ポテンシ
ャルが前記蛍光領域のそれより低い蛍光体。1. A fluorescent region, and a barrier layer that forms a junction with the fluorescent region and covers the surface of the fluorescent region. At least the lowest conduction band potential of the barrier layer is higher than that of the fluorescent region, or the barrier. A phosphor in which the topmost valence band potential of the layer is lower than that of the fluorescent region.
光領域のそれより浅く、かつ前記障壁層の価電子帯最上
端ポテンシャルが前記蛍光領域のそれより低い請求項1
に記載の蛍光体。2. The bottom edge of the conduction band of the barrier layer is shallower than that of the fluorescent region, and the top edge potential of the valence band of the barrier layer is lower than that of the fluorescent region.
The phosphor according to 1.
がアクセプター不純物であって、かつ障壁層の伝導帯最
下端ポテンシャルが蛍光領域のそれより高い請求項1に
記載の蛍光体。3. The phosphor according to claim 1, wherein an activator is present in the fluorescent region, the activator is an acceptor impurity, and the bottom edge of the conduction band of the barrier layer is higher than that in the fluorescent region. .
シャルが表面に近づくにつれて高いか、または前記障壁
層の価電子帯最上端ポテンシャルが表面に近づくにつれ
て低い請求項1に記載の蛍光体。4. The phosphor according to claim 1, wherein at least the conduction band bottom end potential of the barrier layer is higher as it approaches the surface, or the valence band top end potential of the barrier layer is lower as it approaches the surface.
蛍光領域と異なる請求項1に記載の蛍光体。5. The phosphor according to claim 1, wherein the barrier layer has a conductivity type or an active impurity concentration different from that of the fluorescent region.
ン化亜鉛、硫化カドミウム及びセレン化カドミウムから
選ばれる少なくとも一つの化合物半導体、または前記化
合物半導体にさらにマグネシウム、カルシウム、ストロ
ンチウム、バリウム及びマンガンから選ばれる少なくと
も一つの元素を含む化合物半導体である請求項1から5
のいずれかに記載の蛍光体。6. The fluorescent region and the barrier layer are composed of at least one compound semiconductor selected from zinc sulfide, zinc selenide, cadmium sulfide and cadmium selenide, or magnesium, calcium, strontium, barium and manganese added to the compound semiconductor. 6. A compound semiconductor containing at least one selected element.
The phosphor according to any one of 1.
2 O2 Sから選ばれる少なくとも一つの元素を含む化合
物半導体である請求項1から5のいずれかに記載の蛍光
体。7. The fluorescent region and the barrier layer are Y 2 O 3 and Y.
The phosphor according to claim 1, which is a compound semiconductor containing at least one element selected from 2 O 2 S.
下である請求項1から5のいずれかに記載の蛍光体。8. The phosphor according to claim 1, wherein the barrier layer has a thickness of 1 nm or more and 100 nm or less.
子ビームに対して用いられる請求項1から5のいずれか
に記載の蛍光体。9. The phosphor according to claim 1, which is used for an electron beam having an acceleration voltage of at least 15 kV.
または液体中に蛍光体粒子を置き、前記蛍光体粒子の表
面に障壁層をエピタキシャル成長させ、蛍光領域と、前
記蛍光領域と接合を形成してその表面を覆う障壁層を備
え、少なくとも前記障壁層の伝導帯最下端ポテンシャル
が前記蛍光領域のそれより高いか、または前記障壁層の
価電子帯最上端ポテンシャルが前記蛍光領域のそれより
低い蛍光体を得ることを特徴とする蛍光体の製造方法。10. Phosphor particles are placed in a gas or a liquid containing an element constituting the barrier layer, and the barrier layer is epitaxially grown on the surface of the phosphor particles to form a fluorescent region and a junction with the fluorescent region. A barrier layer covering the surface of the fluorescent layer, at least the lowest conduction band potential of the barrier layer is higher than that of the fluorescent region, or the uppermost valence band potential of the barrier layer is lower than that of the fluorescent region. A method for producing a phosphor, which comprises obtaining a body.
ウム及びセレン化カドミウムから選ばれる少なくとも一
つの化合物を含有する化合物半導体を母体とする蛍光体
を、マンガン、マグネシウム、カルシウム、ストロンチ
ウム及びバリウムから選ばれる少なくとも一つの元素を
含有する気体または液体中で熱処理し、前記蛍光体の表
面から所定の深さまで障壁層を形成する請求項10に記
載の蛍光体の製造方法。11. A phosphor having a compound semiconductor as a host material containing at least one compound selected from zinc sulfide, zinc selenide, cadmium sulfide and cadmium selenide is selected from manganese, magnesium, calcium, strontium and barium. The method for producing a phosphor according to claim 10, wherein the barrier layer is formed from the surface of the phosphor to a predetermined depth by heat treatment in a gas or a liquid containing at least one element.
素雰囲気中で熱処理し、その表面から所定の深さまで障
壁層を形成する請求項11に記載の蛍光体の製造方法。12. The method for producing a phosphor according to claim 11, wherein the phosphor having a matrix of Y 2 O 2 S is heat-treated in an oxygen atmosphere to form a barrier layer from the surface to a predetermined depth.
たはアクセプターを拡散させ、その表面から所定の深さ
まで障壁層を形成する請求項10に記載の蛍光体の製造
方法。13. The method for producing a phosphor according to claim 10, wherein a donor or acceptor is diffused from the surface of the phosphor particles to form a barrier layer from the surface to a predetermined depth.
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JP9293193A JPH06299150A (en) | 1993-04-20 | 1993-04-20 | Fluorescent material and its production |
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Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
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JP2005005544A (en) * | 2003-06-13 | 2005-01-06 | Sumitomo Electric Ind Ltd | White light emitting element |
WO2007020785A1 (en) * | 2005-08-18 | 2007-02-22 | Konica Minolta Medical & Graphic, Inc. | Radiographic image conversion panel |
WO2008062693A1 (en) * | 2006-11-21 | 2008-05-29 | Kuraray Luminas Co., Ltd. | Process for producing phosphor precursor |
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1993
- 1993-04-20 JP JP9293193A patent/JPH06299150A/en active Pending
Cited By (9)
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JP2005005544A (en) * | 2003-06-13 | 2005-01-06 | Sumitomo Electric Ind Ltd | White light emitting element |
WO2007020785A1 (en) * | 2005-08-18 | 2007-02-22 | Konica Minolta Medical & Graphic, Inc. | Radiographic image conversion panel |
JPWO2007020785A1 (en) * | 2005-08-18 | 2009-02-19 | コニカミノルタエムジー株式会社 | Radiation image conversion panel |
JP4665968B2 (en) * | 2005-08-18 | 2011-04-06 | コニカミノルタエムジー株式会社 | Radiation image conversion panel |
WO2008062693A1 (en) * | 2006-11-21 | 2008-05-29 | Kuraray Luminas Co., Ltd. | Process for producing phosphor precursor |
JP5300490B2 (en) * | 2006-11-21 | 2013-09-25 | 株式会社クラレ | Method for producing phosphor precursor |
WO2008114649A1 (en) * | 2007-03-16 | 2008-09-25 | Konica Minolta Medical & Graphic, Inc. | Radiation image conversion panel |
JPWO2008114649A1 (en) * | 2007-03-16 | 2010-07-01 | コニカミノルタエムジー株式会社 | Radiation image conversion panel |
US8063387B2 (en) | 2007-03-16 | 2011-11-22 | Konica Minolta Medical & Graphic, Inc. | Radiation image conversion panel |
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