JPS63101480A - Rare earth element oxysulfide phosphor - Google Patents

Abstract

PURPOSE:To improve the brightness of a phosphor, by adding vanadium to a rare earth element oxysulfide phosphor in a specified molar ratio and using europium as main activator. CONSTITUTION:Raw materials for reare earth elements are mixed with raw materials for vanadium, main activator and coactivator by weighing them in such a proportion that an oxide mixture of the formula (wherein Ln is at least one member selected from the group consisting of yttrium, gadolinium, lanthanum and lutetium; X is at least one member selected from the group consisting of terbium, praseodymium, neodymium and erbium; 1X10<-4=x<=2X10<-1>; 0<y<=0.5; 0<=x<=1X10<-4>) is stoichiometrically obtd. Further, a flux (e.g., sodium carbonate) is mixed with the mixture. The mixture is put into a heat-resisting container and fired to obtain the desired rare earth element oxysulfide phosphor. When the phosphor is excited by electron beams, it emits red light having good color purity with high brightness.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a rare earth oxysulfide phosphor containing vanadium and exhibiting high luminance luminescence.

[Conventional technology]

Conventionally, as a rare earth oxysulfide phosphor, one in which an activator is mixed with a certain kind of rare earth phosphor element has been used. Rare earth phosphor elements in this type of phosphor include:
Yttrium, gadolinium, lanthanum and lutetium are commonly used.

Furthermore, at least one of europium, terbium, dysprosium, holmium, neodymium, praseodymium, samarium, and thulium has been used as an activator (Japanese Patent Publication No. 21859/1973, Japanese Patent Publication No. 45/1983).
No. 13943). These rare earth phosphors emit light according to each of the above-mentioned activators when excited by electron beams and ultraviolet rays.

Typical examples that use electron beam excitation include color cathode ray tubes, display tubes, and low-speed electron beam excitation fluorescent display tubes, and typical examples that use ultraviolet excitation include: 5 Fluorescent lamps etc.

However, the brightness of the phosphor achieved as a result of these excitations is not fully satisfactory, and therefore further improvement has been desired.

[Problem that the invention seeks to solve]

Therefore, the present invention aims to further improve the brightness of these phosphors.

[Means for solving problems]

The present invention was made based on the finding that brightness is improved by adding vanadium to a rare earth oxysulfide phosphor.

That is, the present invention has the following configuration.

A rare earth oxysulfide phosphor containing less than 0.5 g atoms and 1 mole of vanadium and europium as the main activator.

(However, as the rare earth, at least one of yttrium, gadolinium, lanthanum, and lutetium is used.) The rare earth oxysulfide phosphor of the present invention further contains terbium, praseodymium, neodymium, and erbium as a coactivator. At least one of the following may be included.

Furthermore, the preferable content of vanadium in the present invention is in the range of I x 10-' to 1.3xlO-'g atoms per mole.

Next, an example of the manufacturing method will be shown.

First, the raw materials for the phosphor include Y2O0, GdzOi,
La2Q,,,1u203,Eu2O3,Tb407,
Rare earth element compounds that can be easily converted into oxides at high temperatures are used, such as rare earth oxides such as pr6oz, Er2O3, and Nd2O3, or nitrates, carbonates, and palmates of these rare earth elements. In addition, vanadium raw materials include vanadium oxide (■○, V2O5, ■0□, V2O5),
Vanadium compounds that can be easily converted into oxides at high temperatures, such as vanadium sulfate (VSO, 7820) and vanadium sulfide (VzSs), are used.

As a scandium raw material, scandium oxide (SC2
03) Alternatively, use a scandium compound that can be easily converted into an oxide at high temperatures, such as sulfate or oxalate.

As fluxes, alkali metal salts commonly used in the production of this type of sulfide phosphor, such as sodium carbonate (Na2C03) and potassium phosphate (K3PO4), can be used. Note that Mg, Mn, and Sm may be further added to a part of the phosphor. Furthermore, in the present invention, sulfur is used as a phosphor host raw material.

Sulfur is used in an amount corresponding to 30 to 5 Qwt% of the mixed oxide.

Further, the fluxing agent is used in an amount corresponding to 5 to 59 wt% of the mixed oxide.

The raw material for the phosphor, the raw material for vanadium, and the raw material for scandium are used in proportions such that a mixture that stoichiometrically satisfies the following compositional formula (I) is obtained.

Composition formula % formula % () (wherein, Ln is at least one of yttrium, gadolinium, lanthanum, and lutetium, and X is at least one of terbium, scandium, praseodymium, neodymium, and erbium,
Also, X1y and 2 are lo-4≦X≦2 X
10-', 0<y≦0.5 and 0≦2≦I X 10
It is a number that satisfies -'. ) In the present invention, the necessary amounts of the various phosphor raw materials described above are weighed and thoroughly mixed to obtain a phosphor raw material mixture.

Next, the obtained phosphor raw material mixture is filled into a heat-resistant container such as an alumina crucible or a quartz crucible and fired.

Firing is carried out in air at a temperature of 900 to 1500°C.

The firing time varies depending on the amount of the phosphor raw material mixture filled in the heat-resistant container, the firing temperature used, etc., but is generally 0.5 to 5 hours. After firing, the obtained fired product is washed and dried to obtain the phosphor of the present invention.

Next, the present invention will be explained in more detail with reference to Examples.

Example 1 Yttrium oxide Y20* 225.8g
Europium oxide Eu2O314g Vanadium oxide V2O51,182g Sulfur
3 110g Sodium carbonate Na2CO+ 50g Potassium phosphate KsPO*・3Hz 30g The above-mentioned phosphor raw materials were thoroughly mixed, the resulting mixture was filled into an alumina crucible, and fired in air at a temperature of 1200°C for 2 hours. After firing, the obtained fired product was thoroughly washed with water and dried. In this way Y2O2S: Euo, os
A Vo, ops fluorophore was obtained.

This phosphor emits light under electron beam excitation. The emission spectrum is shown in FIG. Y, O□5=euo, as
Vol. 13 The luminance of red light emission under electron beam excitation is Y2O. S:εuo,. It was 14% higher than the 8-fluorescent material.

Example 2 Cadolinium oxide Gd20s 362.5g
Europium oxide Eu20s 1.4g
Vanadium oxide V2O50,0455g Praseodymium oxide Pr6oz 0.0017g Sulfur
yellow 3 110
g Sodium carbonate NazCOs 50 g Gd2O2S in the same manner as in Example 1 using the above phosphor raw material
: Miuo, oos Vo, ooosPro, oo
oo+fluorescent material was obtained. The luminance of this phosphor under electron beam excitation is 5Gdz 02 S: Euo-ooe
2% brighter than Pro, oooo+ phosphor.

Example 3 Yttrium oxide Y2O3225, 8g Europium oxide EL1203 14 g Vanadium oxide V2O511, 82g Terbium oxide Tb,
0□ 0.015 g Magnesium oxide MgO
0.04g Sulfur 3
110g potassium phosphate K, PO, 3H203
Y2 was prepared in the same manner as in Example 1 using 0g of the above phosphor raw material.
O2S: Euo, 08 Va, +3Tbo, o
oooo Mgo, oo+ phosphor was obtained. This phosphor is Y2O23:Euo, oaTbo, oooos
lJgo, 2% brighter than the oal fluorophore.

Example 4 Yttrium oxide Y2O3225, 8g Europium oxide Eu2O314g Vanadium oxide V2O50, 455g Scandium oxide 5C2030,034g Terbium oxide Tb
40t 0.15g sulfur
3110g Potassium phosphate K, PO<・3H
Y2O2S: Euo, 08 vO, oossco was prepared in the same manner as in Example 1 using 2030 g of the above phosphor raw material.
, ooosTbo, oooa fluorophores were obtained. This phosphor is Y, O□S:Euo, oasco, 000
It was 1% brighter than the STbO,oooa phosphor.

〔Effect of the invention〕

The phosphor according to the present invention emits red light with high brightness and good color purity under electron beam excitation. Its luminescent color is Ln2O
2S:Eu (wherein Ln is at least one of yttrium, gadolinium, lanthanum, and lutetium). Further, in the above compositional formula [E], even if y and 2 are slightly changed, the emitted light color does not change.

Although FIG. 1 shows the emission spectrum of the luminescent material of the present invention, the rare earth oxysulfide phosphor is a known LnO
It can be seen that the emission spectrum is similar to that of the 2S:Eu phosphor under electron beam excitation.

FIG. 2 is a graph showing the relationship between vanadium doping my value and luminance of the phosphor of the present invention under electron beam excitation. In this figure, the luminance on the vertical axis is X=0.08 y
=o When z=0, that is, conventionally known Ln2O2
S: Euo. It is expressed as a relative value with the luminance of the 8 phosphors set as 100.

As is clear from FIG. 2, the phosphor of the present invention has a y value of Q
In the range <y≦0.5, conventional Ln2O2S'Eu
It exhibits higher luminance than phosphors, especially I x 10-'
It can be seen that higher luminance is emitted in the range of ≦y≦1.3X10-'.

Figure 2 is a graph showing the relationship between the y value and luminance under electron beam excitation in the case of X = 0.08 and Z-0 for Ln2O3S: Eu, vyL phosphor, but europium activator Even when the quantity X changes, X(X
is at least one of terbium, scandium, praseodymium, neodymium, and erbium) coactivation amount 2
It was confirmed that the relationship between the y value and the luminance has the same tendency as in FIG. 2 even when the value changes.

The europium activation amount, that is, the X value in the phosphor of the present invention is suitably in the range of 10-4≦X≦2×10-'.

If the X value is outside this range, the luminance of light emission will drop significantly, which is undesirable.

As described above, the phosphor according to the present invention exhibits good red light emission with the same color purity as Lnz 02 S:Eu under electron beam excitation, and in particular, under electron beam excitation, Ln, O□S:E
It emits light with higher brightness than the u-fluorescent material. Therefore, it can be said that it has increased utility as a red light-emitting component phosphor for display tubes, color television fluorescent display tubes, and the like.

[Brief explanation of the drawing]

FIG. 1 shows the emission spectrum of the phosphor of the present invention. FIG. 2 is under electron beam excitation according to the present invention. y
It is a graph showing the relationship between value and luminance.

Claims (3)

[Claims] (1) A rare earth oxysulfide phosphor containing 0.5 g atom/mol or less of vanadium and europium as the main activator. (However, the rare earth element is at least one member of the group consisting of yttrium, gadolinium, lanthanum, and lutetium.) (2) The rare earth oxysulfide phosphor according to claim (1), which contains at least one member of the group consisting of terbium, scandium, praseodymium, neodymium, and erbium as a coactivator. (3) The rare earth oxysulfide phosphor according to claim (1) or (2), containing 1×10^-^4 to 1.3×10^-^1 g atom/mol of vanadium. .