JPS63101479A - Rare earth element oxysulfide phosphor - Google Patents

Abstract

PURPOSE:To improve the brightness of a phosphor, by replacing part of rare earth elements in a rare earth element oxysulfide phosphor with scandium and using europium as main activator. CONSTITUTION:Raw materials for rare earth elements are mixed with raw materials for scandium, 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; Ln' is at least one member selected from the group consisting of terbium, praseodymium, neodymium and erbium; 0<x<=1.5X10<-1>; 1X10<-4=y<=2X10<-1>; and 0<=z<=1X10<-4>) is stoichiometrically obtd. Further, a flux 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 that emits high-intensity light.

[Conventional technology]

Conventionally, rare earth oxysulfide phosphors have been made by mixing certain rare earth phosphor elements with an activator. Commonly used rare earth phosphor elements in this type of phosphor are yttrium, gadolinium, lanthanum and lutetium.

Furthermore, as an activator, at least one of europium, terbium, disprolum, holmium, neodymium, praseodymium, samarium, and thulium has been used (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.

Examples where electron beam excitation is used include color cathode ray tubes, display tubes, and low-speed electron beam excitation fluorescent display tubes, and examples where ultraviolet excitation is used include fluorescent lamps. can give.

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, an object of the present invention is to further improve the brightness of these phosphors.

[Means for solving problems]

In the present invention, a part of the rare earth in the rare earth oxysulfide phosphor is
This was done based on the knowledge that brightness can be improved by replacing it with scandium.

That is, the present invention has the following configuration.

A rare earth oxysulfide phosphor containing 0.3 g atom or less of scandium and europium as a 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 may further include at least one of terbium, praseodymium, neodymium, and erbium as a coactivator.

Further, the preferred content of scandium in the phosphor of the present invention is in the range of 7.5 x 10 -5 to 7.5 x 10 -2 g atoms per mole.

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

First, the raw materials for the phosphor include Y2O3, Gd2O,...
La, 03, Lu20. ,εu203,Tb,07,P
Rare earth element compounds that can be easily converted into oxides at high temperatures are used, such as rare earth oxides such as r5Oz, Er2O3, and Nd2O3, or nitrates, carbonates, and oxalates of these rare earth elements.

Further, as a raw material for scandium, scandium oxide (Sc20.) or a compound that can be easily converted into an oxide at high temperature, such as a sulfate or an oxalate of the element, is used.

As fluxes, alkali metal salts commonly used in the production of this type of oxysulfide phosphor can be used, such as sodium carbonate (Na2CO3), potassium phosphate (K, PO, etc.). . In addition, NIgs are added to a part of the phosphor.
Mn and Sm may also be added. Furthermore, sulfur is used as a phosphor matrix raw material.

The rare earth raw material and scandium raw material for the above phosphor are:
Stoichiometric formula (Ln, -III 5c11) 203: E
u, Ln't......[I] (wherein, Ln is at least one of yttrium, gadolinium, lanthanum, and lutetium, and Ln
' is at least one of terbium, praseodymium, neodymium and erbium, and X1y and 2
are respectively 0 x ≦ 1, 5 Xl0-', I X 1
0-'≦y≦2 X 10-' and ○≦2≦I
This is a number that satisfies 10-'. ) is used in such a proportion that a mixed oxide represented by:

Sulfur is used in an amount corresponding to 3.0 to 59 wt% of the mixed oxide.

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

Weigh the necessary amounts of each of the phosphor raw materials mentioned above,
Thoroughly mix 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 Y2O3224, 1 g Europium oxide Eu20314 g Scandium oxide
5c20n 1.034 g sulfur
S110
g Sodium carbonate NazCO 350g Potassium phosphate K, PO, .3H, 030g 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 (Yo, 9925SC0,007%>
J2S:tEuo, 08 fluorophore was obtained. This phosphor emits light under electron beam excitation. The emission spectrum is shown in FIG.

The luminance of red light emission under electron beam excitation is Y=02S
: Euo, which was 14% higher than that of the Q11 phosphor.

Example 2 Gadolinium oxide GdaOs 362.5
g Europium oxide εU2O51,4g Scandium oxide 5C203' 0.0103 g Praseodymium oxide Pr5Oz 0.00051g Magnesium oxide Mg0 0.012 g Sulfur
Acid 3 110
g Sodium carbonate Na 2 CO 350g
Potassium phosphate K, PO, 3H, 030 g was treated in the same manner as in Example 1 (Gd0.99992SSCO, ooaots) 2o
, s:Euo, oosMgo, ooo3Pro,
000003 phosphor was obtained. This phosphor is Gd2O2S:Euo, oosMgo, ooo, P under electron beam excitation.
ro, 4% brighter than 000003.

Example 3 Yttrium oxide Y, 03225.7 g Europium oxide Eu20s 14 g Scandium oxide 5C2030,034 g Terbium oxide Tb40t 0.0187 g Sulfur
yellow 3 110
g Potassium phosphate KiPO*・3H,0
30g was treated in the same manner as in Example 1 (Yo, 1sstssco, 00025) 502
s:ELIo, aaTtlo, Gool fluorescers were obtained. This phosphor is Y20□S:Euo. aTbo,.

. . 1 2% brighter than phosphor.

Example 4 Yttrium oxide y2o, 225° 8 g Europium oxide 811203 14 g
Scandium oxide 5C2030,0138g Erbium oxide Er20a 0.0002g Sulfur S
110 g potassium phosphate K3PO,・
3H,030g was treated in the same manner as in Example 1 (Yo, 9999SCO,ooo+)zLs:Euo
, osmi r0. Goofio+ phosphor was obtained. This phosphor is Y2O,S:BLl,... 8εro,. . . .

. 1 phosphor was 3% brighter than the phosphor.

Example 5 Yttrium oxide y, o3224. i gEuropium oxide Eu2O+ 1.4 gScandium oxide 5C2031,034g Manganese chloride M
nCj! z ・4L0 0.099g sulfur
5 100
2030 g of potassium phosphate K3PO4.3H was treated in the same manner as in Example 1 (Yo, 5sassco, 0075) 202S:
Euo, ooaMno, and ooos fluorescers were obtained. This phosphor is Y, 02S:Eu. ,. . , Mn. -8°.

, 10% brighter than phosphor.

〔Effect of the invention〕

The phosphor according to the present invention emits red light with high brightness and good color purity by electron beam excitation. Its luminous color is L
n2O2S:8uy (wherein, n is at least one of yttrium, gadolinium, lanthanum, and lutetium) is equivalent to so.

Further, in the compositional formula CI), it has the feature that the emitted light color does not change even if X and 2 are slightly changed.

Note that although FIG. 1 shows the emission spectrum of the phosphor of the present invention, the oxysulfurized rare earth phosphor of the present invention
It can be seen that the luminescence spectrum is similar to that of the n,O□S:Eu phosphor under electron beam excitation.

Further, FIG. 2 is a graph showing the relationship between the scandium substitution ix value and the luminance of the phosphor of the present invention under electron beam excitation. In this figure, the luminance on the vertical axis is expressed as a relative value when x=Q, that is, with the luminance of the conventionally known Ln2O2S:Eu phosphor as 100.

As is clear from FIG. 2, the phosphor of the present invention has an X value of Q<
In the range x≦1.5X10-', conventional n202
S: Shows higher luminance than Eu phosphor, especially 7.
It can be seen that higher luminance is emitted in the range of 5X10-'≦8≦7.5X10-''.

In addition, Fig. 2 shows (Ln+-xscJ 202S: 巳uy
This is a graph showing the relationship between the X value and emission brightness under electron beam excitation when y=0.08.2=0 among Ln' 2 phosphors. It was confirmed that the relationship between the X value and the luminance is the same as that shown in FIG. 2 even when the Ln' amount (z) is changed.

The europium activation amount, ie, the y value, in the phosphor of the present invention is suitably in the range of 10-4≦y≦2XlO-'.

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

As described above, the phosphor of the present invention can be used under electron beam excitation.
It shows good red light emission with the same color purity as n20°S:Eu, and in particular shows higher luminance than Ln2O2S:Eu phosphor under electron beam excitation. 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 a graph showing the relationship between the X value and luminance under electron beam excitation according to the present invention. Procedural amendment 62, 1. -6 Showa year, month, day 1, case description 1986 patent application No. 248979
No. 2, Title of the invention Rare earth oxysulfide phosphor 3,
Relationship with the case of the person making the amendment Applicant name: Kasei Optonics Co., Ltd. 4, Agent 5, Date of amendment order: Self The Invention Box is corrected as follows.

Claims (3)

[Claims] (1) Rare earth oxysulfide phosphor containing less than 0.3 g atoms/mol of scandium and europium as the main activator. (However, the rare earth is at least one of yttrium, gadolinium, lanthanum, and lutetium.) (2) The rare earth oxysulfide phosphor according to claim (1), which contains at least one of terbium, praseodymium, neodymium, and erbium as a coactivator. (3) Scandium content is 1.5 x 10^-^4 ~
The rare earth oxysulfide phosphor according to claim 1 or 2, wherein the amount is in the range of 1.5 x 10^-^1 g atoms/mol.