JPS6227488A - Phosphor - Google Patents

Abstract

PURPOSE:To obtain a luminescent phosphor capable of stably exhibiting an excellent sublinear relationship between current density and brightness of luminescence during an increase in the current density of a stimulating electron beam, by calcining a mixture of particular raw materials of a phosphor. CONSTITUTION:At least one compd. (A) selected from among a group of compds. consisting of Y2O3, Gd2O3, La2O3 and Lu2O3 and a group of compds. which can be easily converted into the above oxides at a high temp. is mixed with Eu2O3 or a compd. which can be easily converted into Eu2O3 at a high temp. (B), TiO2 or a compd. which can be easily converted into TiO2 at a high temp. (C) and SnO2 or a compd. which can be easily converted into SnO2 at a high temp. (D), CeO2 or a compd. which can be easily converted into CeO2 at a high temp. (E) and CaO or a compd. which can be easily converted into CaO at a high temp., thereby obtaining a mixed oxide. The mixed oxide is sufficiently mixed with salt flux (F), such as Na2CO3 or K3PO4, to obtain a phosphor raw material mixture. The mixture is calcined at 900-1,500 deg.C for 0.5-5hr to obtain a red luminescent phosphor of the formula (wherein Ln is Y, Gd, La or Lu; M is Ti or Sn; M' is Ce or Ca; 2X10<-4=x<=0.18; 5X10<-6=y<=5X10<-2>; and 2X10<-6=z<=6X10<-2>).

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a phosphor. More specifically, the present invention relates to a phosphor that exhibits a sublinear current density-emission brightness relationship as the current density of a stimulating electron beam increases.

[Prior Art] Recently, multicolor cathode ray tubes have come into practical use as terminal display devices for computers, display devices for aircraft control systems, and the like. This multicolor cathode ray tube consists of a phosphor that exhibits a superlinear excitation energy-emission brightness relationship as the energy of the stimulating electron beam increases, and a phosphor that exhibits a sublinear excitation energy-emission brightness relationship as the energy of the stimulating electron beam increases. This is a cathode ray tube with a phosphor film composed of two types of phosphors that emit light in different colors, and the emitted color of the phosphor film is changed by changing the energy of the stimulating electron beam.
This allows multicolor display.

The multicolor cathode ray tubes are classified into two types depending on the method of changing the energy of the stimulating electron beam. In other words, there are two types: one that changes the energy of the stimulating electron beam by changing the accelerating voltage, and the other that changes the energy of the stimulating electron beam by changing the current density.The former is called a voltage modulated multicolor cathode ray tube. , the latter is called a current-modulated multicolor cathode ray tube.
Please refer to pages 106 to 117 of the July 2, 1973 issue for information on current modulated multicolor cathode ray tubes.
Please refer to Publication No. 225.

Current modulated multicolor cathode ray tubes have the advantage that the structure of the electron gun, electron gun control circuit, etc. are significantly simpler than voltage modulated multicolor cathode ray tubes.

Despite this, most of the multicolor cathode ray tubes currently being put into practical use are voltage modulated multicolor cathode ray tubes. This indicates that there are few phosphors suitable for use in current-modulated multicolor cathode ray tubes, ie, phosphors that exhibit a sufficiently superlinear or sublinear current density-luminance relationship as the current density of the stimulating electron beam increases. This is because they have not been

Conventionally, copper and aluminum activated phosphors containing an appropriate amount of at least one of iron, cobalt, and nickel have been used as phosphors that exhibit a superlinear current density-emission brightness relationship when the current density of the stimulating electron beam increases. Zinc sulfide green emitting phosphor (ZnS: Cu, At) and silver-activated zinc sulfide cadmium blue-green to red emitting phosphor [(Zn, Cd)S:Ag, as is well known, this phosphor exhibits blue-green to red light emission in response to changes in the molar ratio of ZnS and CdS. In addition, a manganese-activated zinc silicate green-emitting phosphor (Zn2 S
ioa:Mn) is known.

In multi-color cathode ray tubes, in order to widen the range of change in display color, generally i) a red-emitting phosphor exhibiting a super-linear excitation energy-emission brightness relationship and a green-emitting phosphor exhibiting a sub-linear excitation energy-emission brightness relationship; or ii) a combination of a blue-green to green-emitting phosphor that exhibits a superlinear excitation energy-emission brightness relationship and a red-emitting phosphor that exhibits a sublinear excitation energy-emission brightness relationship. configured. From this point of view, in current modulated multicolor cathode ray tubes, the above-mentioned iron,
The (Zn, Cd)S:Ag red light-emitting phosphor containing at least one metal selected from cobalt and nickel (showing a superlinear current density-emission brightness relationship) and the Zn2SiO4:Mnfi color light-emitting phosphor (sublinear ZnS: Cu, A
I green-emitting phosphor or containing at least one metal selected from the above-mentioned iron, cobalt and nickel (Zn,
Cd)S:Ag To be combined with a blue-green to green-emitting phosphor (all exhibiting a superlinear current density-emission brightness relationship), when the current density of the stimulating electron beam increases, the current density is sufficiently sublinear. A red-emitting phosphor that exhibits a luminance relationship is strongly desired.

The present invention was made under the above-mentioned circumstances,
It is an object of the present invention to provide a phosphor, in particular a red-emitting phosphor, which exhibits a sufficiently sublinear current density-emission brightness relationship when the current density of a stimulating electron beam increases.

A europium-activated rare earth oxysulfide phosphor having the composition formula Ln2O2S:Eu (where Ln is at least one of yttrium, gadolinium, lanthanum, and lutetium) exhibits a change in the amount of Eu activation under electron beam excitation. It is well known that it exhibits high-intensity yellow to red light emission in response to . For example, Y2 is one of these phosphors and has a relatively large amount of Eu activation.
O2S:Eu phosphor is currently in practical use as a red emitting component phosphor for color television cathode ray tubes.

It is known that the Ln202S:Eu phosphor exhibits a very slightly sublinear current density-emission brightness relationship as the current density of the stimulating electron beam increases, as illustrated in FIG.

In order to achieve the above object of the present invention, the present inventors have
Various studies have been conducted to improve the sublinearity of the current density-emission brightness relationship exhibited by O2S:Eu phosphors. As a result, when M (M is at least one of titanium and tin) is used as a co-activator for Eu, the sublinearity of the current density-emission brightness relationship exhibited by the Ln2O2S:Eu phosphor can be enhanced. (Japanese Patent Application No. 1983), and furthermore, as a co-activator for Eu, M (M is at least one of titanium and tin) and M'(M' is at least one of calcium and cerium) can be used as a co-activator for Eu. 1 type) in a specific range of amount, Ln202 S:Eu, M
(M is at least one of titanium and tin) The sublinearity of the current density-emission brightness relationship exhibited by the phosphor can be increased, and this M (M is at least one of titanium and tin) and M'(M'
is at least one of calcium and cerium)
The present inventors have discovered that in a specific range of the coactivation amount, the above-mentioned sublinearity becomes significantly high, and a stable and good phosphor can be obtained, and the present invention has been completed.

[Means for Solving the Problems] The phosphor of the present invention has a compositional formula of L n202 S :E u )(MyM' z(
However, Ln is at least one of yttrium, gadolinium, lanthanum, and lutetium, M is at least one of titanium and tin, M' is at least one of calcium and cerium, and x, y and 2 are each 2XIO-4≦X≦
0.18゜5X10-6≦y≦5×10″″2 and 2
Europium, M (M is at least one of titanium and tin) and M'(M' is at least one of calcium and cerium) Type 1) activated rare earth oxysulfide phosphor.

When the current density of the stimulating electron beam increases, this phosphor
Ln202 S: Eu, M (M is at least one of titanium and tin) shows a current density-emission brightness relationship with higher sublinearity than phosphors, especially M'(M' is at least one of calcium and cerium). at least one of the above) coactivation amount cy) z value is 5X10-5≦
Phosphors in the range of 2≦2XlO-2 (7) exhibit a current density-emission luminance relationship with significantly high sublinearity.

The phosphor of the present invention is manufactured by the manufacturing method described below.

First, as raw materials for the phosphor, l) the first compound group consisting of yttrium oxide (Y203), gadolinium oxide (CD203), lanthanum oxide (La203), and lutetium oxide (Lu203), as well as nitrates, sulfates, carbonates, and oxalates; , hydroxide etc. at high temperature easily Y2O3, Gd203, La203
and at least one compound selected from the second group of compounds consisting of yttrium compounds, gadolinium compounds, lanthanum compounds, and lutetium compounds that can be converted into Lu2O3.
2) Europium oxide (EuzO3) and its nitrates, sulfates, carbonates, oxalates, hydroxides, etc., which easily form Eu at high temperatures.
At least one compound selected from the group of compounds consisting of europium compounds that can be converted to 2O3, 3) A group of compounds consisting of titanium compounds that can be easily converted to oxides at high temperatures, such as titanium oxide (Ti02) and sulfates and hydroxides. 4) At least one compound selected from the group consisting of tin oxide (Sn02) and tin compounds that can be easily converted into oxides at high temperatures such as nitrates, sulfates, and hydroxides. , 5) Cerium oxide (Ce02) and nitrates, sulfates,
At least one compound selected from the group consisting of cerium compounds that can be easily converted into oxides at high temperatures such as carbonates, oxalates, and hydroxides;
) and carbonates, hydroxides, nitrates, etc., easily C at high temperatures.
At least one compound selected from the group of compounds consisting of calcium compounds that can be converted to aO, 7) Sulfur, 8) Alkali commonly used in the production of oxysulfide phosphors such as sodium carbonate (Na2CO3) and potassium phosphate (K3PO4). A flux such as a metal salt is used.

The above 1) and 7) are the base raw materials, and the above 2) is Eu
The above 3) is a Tt co-activator raw material, 4) is a Sn co-activator raw material, and L 5)
is a Ce coactivator raw material, and 6) is a Ca coactivator raw material. - 1), 2), 3), 4), 5) and 6) above
is a chemical composition formula (%) (where Ln is at least one of yttrium, gadolinium, lanthanum, and lutetium, 1M is at least one of titanium and tin, and M'
is at least one of calcium and cerium, and X, y and Z are each 2X10-4≦X
≦0.18.

5X10-6≦y≦5X10-2 and 2×10-6≦
The mixed oxide is used in such a proportion that a mixed oxide expressed by the following formula is obtained. The above 7) is used in an amount corresponding to 30 to 60% of the above mixed oxide, and the above 8) is used in an amount corresponding to 5% of the above mixed oxide.
It is used in an amount corresponding to 50% by weight. The required amount of each phosphor raw material is 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.

When the current density of the stimulating electron beam increases, the phosphor of the present invention exhibits a sublinear current density-emission brightness relationship. 1) The sublinearity of the current density-emission luminance relationship exhibited by the phosphor of the present invention is determined by the amount of Eu activation and M (M
is at least one of titanium and tin) Ln202 S:Eu, M (M is at least one of titanium and tin) coactivation amount is higher than sublinearity.

FIG. 1 is a graph illustrating the current density-emission brightness relationship exhibited by the phosphor of the present invention, and shows Y2O2S:Eu
This shows the current density-emission brightness relationship exhibited by the O,08"10.0005'CaO,005 phosphor. In Figure 1, the luminance on the vertical axis is Y2O2":EuO at each current density value. , 08"10.0005 The specific luminance is normalized so that the value in IBA/crrf becomes 100 by multiplying the specific luminance by a certain magnification, taking the luminance of the phosphor as 100%.

The following can be understood from Figure 1. That is, since the Y2O25""0.08"'0.0005 phosphor exhibits a sublinear current density-emission brightness relationship, it is clear that Y202S: Euo, oa.

"0.0005" ao, more linear than 005 phosphor 1
It shows the current density-emission brightness relationship, and the current density-
Sublinearity related to luminescence brightness depends on Eu activation amount and T
Y2O2S with the same i-coactivation amount: Eu0108'T
This is higher than the sublinearity of the current density-emission brightness relationship exhibited by the i0.0005 phosphor.

The sublinearity of the current density-emission brightness relationship exhibited by the phosphor of the present invention is determined by the coactivation amount of M (M is at least one of titanium and tin) and M'(M' is at least one of calcium and cerium). (at least one kind of) is a function of the amount of co-activation. For example, when the current density of the stimulating electron beam is 1.0 A/crn' and 6.0 pA/cm',
・If the emission brightness of the Caz phosphor is A1 and B, respectively, the sublinearity of the current density-emission brightness relationship exhibited by this phosphor is expressed as Bl/Al (of course, the smaller the value of Br/At, the more sublinearity ), this sublinearity is Ca
It changes depending on the amount of co-activation.

Figure 2 shows Y 202 S : E u o , o a
.

2 is a graph showing the relationship between the Ca coactivation amount of a TiO,0005,Caz phosphor and the sublinearity of the current density-emission brightness relationship exhibited by this phosphor. In Figure 2, the vertical axis representing sublinearity is BI A2.
/AI B2 value. Here, A2 and B2 are respectively Y 202 S ; E u o ,
o ao''0.0005゜Current density of Y2O2S:Eu0908゛Ti0.0005 phosphor with the same Eu activation amount and Ti coactivation amount as that of Ca2 phosphor: 1.0 gA/crrI' and 6.0 g A
/ cm is the emission brightness at m'. BI A2
/At B2 value smaller than 1 means Y2O
The sublinearity of the current density-emission brightness relationship exhibited by the 2":EuO,08"10.0005'Ca2 phosphor is higher than the sublinearity of the current density-emission brightness relationship exhibited by the Y2O2S:Eu0008・Tio,ooo5 phosphor. BIA2/AlB2
A value greater than 1 means the opposite.

As is clear from FIG. 2, Y 202 S: E u o, o ao”0.
0005°Ca Current density exhibited by phosphor -
The sublinearity of the emission ring degree changes depending on the amount of Ca coactivation. Also, as is clear from Figure 2, Y2O
2"EuO,0B 0.0005', T1 The sublinearity of the current density-emission ring degree relationship exhibited by the Ca phosphor is such that the binary Ca coactivation amount is 2X10-
Y2O2"E when in the range of 6≦2≦6×10""2
uO,08'''0.0005 This is higher than the sublinearity of the current density-emission brightness relationship shown by the phosphor. This means that the Tt coactivation amount (y value) is 5XiO-6≦
This is effective when y≦5×10 −2 . It is based on such knowledge that the y value and the X value are defined in the range of 5X10-6≦y≦5X1O-2 and 2X10-6≦2≦6X10-2 in the present invention, respectively. Especially when the X value is 5
When X10-5≦2≦2X10-2, Y2O2S:Eu, o8. Ti, Ca fluorescence
The z-body shows a current density-emission brightness relationship with high sublinearity.

Note that FIGS. 1 and 12 show data when the rare earth element Ln constituting the matrix is Y, the co-activating element M is Ti, and the co-activating element M' is Ca, but when Ln is Gd
, La or Lu, and Ln is Y, Gd,
Results similar to those in FIGS. 1 and 2 were also obtained when two or more of La and Lu were used. Similarly, results similar to those in FIGS. 1 and 2 were obtained when M was Sn and when M was two types, Ti and Sn. Furthermore, results similar to those in FIGS. 1 and 2 were obtained when M' was Ce or when M' was two types of Ca and Ce.

In the present invention, the Eu activation amount (X value) is defined in the range of 2X10-4≦X≦0.18 from the viewpoint of luminance.

The phosphor of the present invention having an X value within the above range emits yellow to red light in response to changes in the X value. Especially when the X value is 2X10-
A phosphor in the range of 2≦X≦0116 emits red light with good color purity.The amount of Eu has almost no effect on the sublinearity of the current density-emission brightness relationship exhibited by the phosphor, and M(M is at least one of titanium and tin) and M'(M' is at least one of calcium and cerium) have little effect on the emission spectrum (emission color) of the phosphor. That is, the emission spectrum of the phosphor of the present invention is almost the same as that of the Ln2O3S:Eu phosphor with the same amount of Eu activation.

As explained above, according to the present invention, when the current density of the stimulating electron beam increases, a phosphor that exhibits a good and stable sublinear current density-emission luminance relationship can be obtained. Among the phosphors of the present invention, Eu Activation amount X value is 2X10-2≦
The phosphor in the range of X≦0.16 emits red light with good color purity, and therefore ZnS:Cu contains at least one metal selected from the above-mentioned iron, cobalt, and nickel.

AI green-emitting phosphor or containing at least one metal selected from the above-mentioned iron, cobalt and nickel (Zn
, Cd)S:Ag is suitable for forming a fluorescent film of a current modulated multicolor cathode ray tube in combination with a blue-green to green-emitting phosphor (all of which exhibit a superlinear current density-emission brightness relationship). Furthermore, the phosphor of the present invention can also be used in electron beam excitation display tubes other than the above-mentioned current modulated multicolor cathode ray tube.

Next, the present invention will be explained by examples.

Example 1: Yttrium oxide Y203 225.8 g Europium oxide Eu203 14.1 g Titanium oxide Ti02 0.04 g Sulfur S 20 g Sodium carbonate Na2CO3 0 g Potassium phosphate K3 PO4-3H 200 g Calcium carbonate CaCO3 0.5 g 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 Y 202 S:
Eu o, o a.

"0.0005" ao, 005 phosphor was obtained. When the current density of the stimulating electron beam increases, this phosphor exhibits a sublinear current density-emission brightness relationship, and as shown in Figures 1 and 2, the sublinearity of the current density-emission brightness relationship is Y2O25 ""0.08" was higher than 10.0005 phosphor.

Example 2: Yttrium oxide Y2 o.

225.8g Europium oxide Eu203 10.6g Titanium sulfate Ti(SO4)2 1.2g Cerium nitrate Ce (NO3)3 6H200,0
087g Calcium carbonate CaCO3 0.05g Sulfur S 20g Sodium carbonate Na2CO3 0g Potassium phosphate K3 po,...3H200g Y2O2 in the same manner as in Example 1 using each of the above phosphor raw materials
"EuO,06"'(1005'CeO,00002°
A CaO,0005 phosphor was obtained. When the current density of the stimulating electron beam increases, this phosphor exhibits a sublinear current density-emission brightness relationship, and the sublinearity of the current density-emission brightness relationship is Y2O2S""0.06=T'0.005 fluorescence It was higher than my body.

Example 3: Yttrium oxide y2 o3 225.8g europium oxide Eu203 17.6g tin oxide 5n02 0.03g nitric acid)IySiuL Ca (NO3) 2 ・4H
200.24g Sulfur S 20g Sodium carbonate Na2CO3 0g Potassium phosphate K3 PO4-3H 200g YO in the same manner as in Example 1 using each of the above phosphor raw materials
S: Euo, t, Sno, o
o02.

A CaO,001 phosphor was obtained. When the current density of the stimulating electron beam increases, this phosphor exhibits a sublinear current density-emission brightness relationship, and the sublinearity of the current density-emission brightness relationship is YOS:Eu,Sn
o, ooo22 2 0.1 It was higher than that of the phosphor.

[Brief explanation of drawings]

FIG. 1 is a graph illustrating the sublinear current density-emission brightness relationship exhibited by the phosphor of the present invention. FIG. 2 is a graph illustrating the relationship between the Ca coactivation amount of the phosphor of the present invention and the sublinearity of the current density-emission luminance relationship exhibited by this phosphor. FIG. 3 is a graph illustrating the slightly sublinear current density-emission brightness relationship exhibited by the Ln2O2S:Eu phosphor. Electricity width (μA/cm2) Figure 3 V-fitting length (pA/cm2)

Claims (3)

[Claims] (1) Composition formula Ln_2O_2S: Eu_xM_yM'_z (however, L
n is at least one of yttrium, gadolinium, lanthanum and lutetium, M is at least one of titanium and tin, M' is at least one of calcium and cerium, and x, y and z are each 2×10^-^4≦x≦0.
18, is a number that satisfies the following conditions: 5×10^-^6≦y≦5×10^-^2 and 2×10^-^6≦z≦6×10^-^2), A rare phosphor that exhibits a sublinear current density-emission brightness relationship when the current density of a powerful electron beam increases. (2) The above z is 5×10^-^5≦z≦2×10^-
The phosphor according to claim 1, characterized in that the number satisfies the condition ^2. (3) The phosphor according to claim 1 or 2, wherein x is a number satisfying the condition 2×10^-^2≦x≦0.16.