JPS62197487A - Production of phosphor - Google Patents

Abstract

PURPOSE:To obtain a blue phosphor for a color display tube which is excellent in afterglow, by firing and pulverizing a mixture of strontium, calcium and antimony compds., adding a manganese compd. and a flux to the mixture, again firing and pulverizing the mixture and further firing the pulverized mixture. CONSTITUTION:A mixture of a strontium compd. (e.g., SrCO3), a calcium compd. (e.g., CaCO3), and an antimony compd. (Sb2O5) which are each an oxide or a compd. capable of being converted into an oxide upon being heated is fired at 800-1,000 deg.C in air to obtain a firing compd. (A) of formula I (wherein 0<=u<=0.15). The component A is then pulverized. To the powder thus obtd. are added a manganese compd. which is in the form of an oxide or a compd. capable of being converted into an oxide upon being heated (e.g., Mn2P2O7) and a flux selected from among K2SO4, Rb2SO4, Na2SO4, and Cs2SO4. The mixture is fired in an oxidizing atmosphere at 1,000-1,100 deg.C to obtain an Mn<2+>- doped firing product (B). The component B is then pulverized. The power thus obtd. is fired in an oxidizing atmosphere at 1,150-1,250 deg.C to obtain a phosphor of formula II (wherein 0.03<=v<=0.3).

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a long afterglow blue phosphor for color display tubes.

[Conventional technology]

With the spread of computers, the demand for high-definition color display tubes as input/output terminals is rapidly increasing. However, if ordinary short afterglow phosphors are used in the display tube as described above, and only the number of scanning lines is increased by refreshing at a commercial frequency, the screen will flicker and the fatigue of terminal users will increase. do. Therefore, a method of using a long afterglow phosphor without increasing the frame frequency of the screen, and a method of increasing the frame frequency using a short afterglow phosphor have been adopted. In the latter case, components such as circuits, semiconductor elements, and polarization yokes are required, resulting in extremely high costs and technical difficulties.

Therefore, the former method is considered more preferable.

Currently, in color display tubes, among the three primary color phosphors, b (P39. Long afterglow) is used for green, and Zn5 (POa)2 is used for red.
: Mn (P27. long afterglow), ZnS for blue color : A
g, Cl (P22B, short afterglow), or ZnS
: Ag, M, X (However, M=Ga or ■Ω
, X=halogen or Aj') is used (JP-A-58-83084, JP-A-58-83085, Hase,
Yoshida, Mikami: Proceedings of the 205th Fluorescent Society Conference, pp. 9-
page 10). Although not in practical use, SrSb, O,:Mn is known as a blue phosphor (
M, -L, Yu, A11salu: Izveestia akajiemii nauka nis nis nis-
zvest, Akad, Nauk, 5SSR)2
3 (1959) 1346-1348).

[Problem that the invention seeks to solve]

When ZnS:Ag, Cl is used as a blue phosphor, since the phosphor has a short afterglow, the color of the screen may change in the middle of the afterglow due to the difference in afterglow characteristics with other colors. ,
Moreover, the flicker reduction effect is also reduced.

Furthermore, when using ZnS:Ag, M, or It has drawbacks such as being "drawn" and the color of the emitted light changing depending on the current density.

Furthermore, 5rSb20. : Although the crystal structure and emission spectrum of Mn have been clarified, other properties are unknown, so the above phosphor was synthesized by a conventional method and its emission properties were investigated.

As a result, the luminescence of the phosphor exhibits a long exponential decay, and the decay characteristics do not change depending on the current density, and the chromaticity coordinates X = 0.10. It was revealed that the blue color has a high degree of saturation at Y=0.125, and that there is relatively little luminance saturation phenomenon. However, the only drawback is low brightness. An object of the present invention is to obtain a method for producing a blue phosphor suitable for use in color display tubes as described above.

[Means for solving problems]

The above purpose is (Sr1-uCau)1. , -vMnvS
This can be achieved by devising a synthetic method for b206. That is, oxides of Sr, Ca, Mn, and Sb, or compounds that can become oxides of each of the above elements by heating, and as a flux, at least one of SO4°Rb, SO4, NazSO4, and Cs, SO4. The general formula % formula % is calculated using the compound as a raw material. However, 0 (u (0,15, 0,03<v< 0
．． In the manufacturing method for obtaining the phosphor No. 3, the manufacturing method includes a first step of mixing an Sr compound, a Ca compound, and an Sb compound and firing the mixture in air at 800°C to 1000°C, and pulverizing the fired product. A second step of adding a Mn compound and 7 lux and firing in an oxidizing atmosphere at 1000°C to 1100°C;
This can be achieved by performing a third step of firing in an oxidizing atmosphere at a temperature of 1250°C to 1250°C.

[Effect]

The first step is Mn (Sr1-uCau)Sb
This is the process of making 206. In this step, the divalent Mn compound
λJr+4'' L-based I+ is colored. Therefore, first, a matrix without Mn addition is synthesized.

Here, in order to facilitate doping with Mn2+ in the second and subsequent steps, Sb2o with poor crystallinity (Sr1-uCau),
It is necessary to make (5r1-uCau)SbzOs starts to form at temperatures above 800°C, and crystallinity improves above 1000°C, so the firing temperature range was set at 80°C.
The temperature was limited to 0-100°C.

The second step is the step of doping Mn2+.
If fired at around 0°C, Mn2+ will be oxidized and become Mn'', resulting in coloration and a decrease in efficiency, so it is desirable to fire at a temperature lower than 1100°C. Also, at a temperature lower than 1000°C, Mn2+ will not diffuse sufficiently. Become.

From this, the firing temperature range for the second step was set at 1000 to 1
The temperature was limited to 100°C. The above firing is performed in an oxidizing atmosphere.

Although it is possible to perform firing in air, it is preferable to perform firing in air supplemented with oxygen. Also, the flux is M n
It prevents oxidation of 2+, facilitates diffusion, and also promotes crystallization of the host.

The third step is a step of promoting crystallization. In the above-mentioned 2nd engineering Pl, the dry crystal width is 1r.
Even when fired at around 1200°C, no coloration occurs due to oxidation of Mn. By firing in the range of 1150-1250°C, conventional ZnS2AglGa, cl! The temperature was limited to the above temperature range in order to obtain a product with higher brightness. The calcination is performed in an oxidizing atmosphere, preferably in air supplemented with oxygen, similar to the calcination in the second step. Appropriate firing time in each step is about 30 minutes. Among the reagents used, a phosphor with high brightness can be obtained by using the Mn compound in the form of Mn or P2O. The optimum amount of the above flux addition is the alternative 4
It is 0 to 50% by weight.

Since the fired product that has gone through the above three steps contains a trace amount of Mn compound that has not reacted with the flux, it is necessary to wash it with dilute hydrochloric acid, tartaric acid, or ethylenediaminetetraacetic acid after washing with water.

The phosphor obtained as described above is, for example, (SrO,
gMnol) Sb, Os and (srO,85caO
, 15) 0.97 The brightness of Mn0f13Sbz○6 by electron beam excitation (25 KV, 0.15 μA/c+() is 1 compared to ZnS: Ag, Ga, and C1, respectively.
It was 6% and 60 inches higher.

The above blue long afterglow phosphor, InBO32Eu, CaS
:Mn, (Ca, Mg) S: Mn or Z
n3(PO4)2: By combining Mn with any long afterglow yellow to red phosphor, a white phosphor for display tubes with less flickering can be obtained.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a blue long afterglow phosphor Sro, g MnO, I 5b206 manufactured by the phosphor manufacturing method according to the present invention.
FIG. 2 is a diagram showing the luminescence chromaticity coordinates of the phosphor and cathode ray tube described in the examples, and FIG. 3 is a diagram showing the afterglow characteristics of Srl-
FIG. 3 is a diagram showing the dependence of brightness on Mn concentration (V) in vMnvSb206.

Example I 1,328 g of Sr CO3 and 3.235 g of 5b20S
The mixture was mixed well, packed thinly into an alumina boat, and fired in air at 1000°C for 30 minutes. Add 0.1688 g of Mn2P207-3 HzO and 1892 g of 2SO4 to the above fired product, mix in an agate mortar, and mix at 10rr+I! The mixture was packed in an aluminum crucible and fired at 1100°C for 30 minutes in an oxidizing atmosphere. Next, the fired product is crushed and packed in an aluminum crucible, and further fired at 1200° C. for 30 minutes in an oxidizing atmosphere. The above-mentioned fired product was washed with water to remove KzS Oa, and further washed with water of 0.05 to remove a trace amount of unreacted Mn compound.
After treatment with 2N hydrochloric acid, it was washed with water. The thus obtained phosphor has a composition of SrO, g Mnol 5b2o6, and is subjected to electron beam excitation (25 KV, 0.15 μA/
aj') brightness is ZnS:Ag, Ga,
It was 16% higher than Cl. FIG. 1 shows a comparison of the afterglow characteristics with a conventional long afterglow blue phosphor. l in the diagram
are S rQ, 9 M no, I S b according to the present example.
In 206, 2 is a characteristic of a conventional phosphor. Note that the chromaticity coordinate 3 shown in FIG. 2 is the long afterglow blue phosphor of this example. Further, FIG. 3 shows a state in which the brightness in Srl-vMnvSb 206 depends on the Mn concentration.

Example 2 SrCOs 1.217g, CaCO50,146g
and Sb, 053.235 g, were thoroughly mixed, and the mixture was calcined with alumina powder. Mn2P2O7 in the above fired product
・3H,O to 0.051g, So, 1.860
g and mixed in an agate mortar, packed in a 10 m aluminum crucible, and heated at 1100'C in an oxidizing atmosphere.
Bake for 30 minutes. The fired product was then crushed, packed into an aluminum pot, and further heated at 1200°C in an oxidizing atmosphere.
Bake for 30 minutes. The phosphor obtained by performing the subsequent steps in the same manner as in Example 1 was (sro, 85 caO, 15
)0.97 Mn0.035b206, and the brightness by electron beam excitation (25KV, 0.15μA/cyl!) is 6 compared to ZnS: Ag, Ga, and Cl.
0 section was expensive.

Example 3 A composition prepared by the same procedure as in the above example was (Sr
0.87 CaO, +3) 0.9 Mno, +S
b20s long afterglow blue phosphor (4 in Figure 2) and C
a0.998 MnO, QO3S (8 in Figure 2) were weighed out at a weight ratio of 9:1, mixed thoroughly, and then 9 was prepared by the well-known sedimentation method in a water glass suspension.
An inch monochrome display tube was created. The color of the emitted light from the display tube is as follows: V=n′2T;, V=I”l
QQ (Flute 9PA Yu +') mn Guo 4'hX White (P
aper White), 10% afterglow time is 25m
It was 5. ZnS: Ag, Cl (P22B,
A long afterglow display tube with the same color tone using 11) in Figure 2 as the blue component had a change in color tone during the afterglow, but
In the display tube of this example, no change in color tone was observed in the time range from the peak of luminescence to attenuation to 1/10 of the peak of luminescence.

Example 4 (S ro9s Ca O, 05) 0.9 MnO, l
S b206 (long afterglow blue phosphor with D composition (
4) in Figure 2 and In0.96EuO,04BO3 (9 in Figure 2) were mixed well in a weight ratio of 17:1. The emission chromaticity coordinates of the above mixture are X=0.23,
It was light blue (14 in Figure 2) with y = 0.24. This color tone is ZnS: Ag, Cl CP22
B) (7) Visibility is higher than color tone (and is in demand for display purposes. The 10% afterglow time is approximately 35 m5,
No change in color tone was observed during afterglow.

Example 5 (sro, 73 Ca0.27 )0.9 MnO,l
Sb20s (6 in Figure 2) and (Zn5 (P 04)
2: Mn) (P27.10 in Figure 2) and 1
．． A 9-inch monochromatic display tube was prepared by mixing the materials at a weight ratio of 5:■ and performing a sedimentation method in a water glass suspension. The emitting color of the display tube above is "Paper
White" (12 in Figure 2).The IO% afterglow time was 100 ms.Compared to a long afterglow display tube of the same color using P22B, the display tube of this example had no afterglow. was long, and there was only a slight change in color tone during the afterglow.

Example 6 (SrO,95Ca0.05) 0.95 Mno,
os Sb206 (4 in Figure 2) and cao, 999 M
nO, ool S (8 in FIG. 2) were thoroughly mixed in a weight ratio of 30=1, and a 9-inch monochrome display tube was prepared by a sedimentation coating method in a water glass suspension.

The emission color of the above display tube is X=0.25. y=0
．． 29 (13 in Figure 2), and 1
The zero afterglow time was 3 Qms. Conventional same-color long afterglow display tubes use P22B as the blue component, and the change in color tone is significant, whereas in this example, no change in color tone was observed.

〔Effect of the invention〕

As described above, the method for manufacturing a phosphor according to the present invention includes Sr,
Oxides of Ca, Mn, and Sb, or compounds that can be turned into oxides of the above elements by heating, and a small amount (both one type of compound) of 2SO4, Rb2SO4, Na, SO4, and C3zSo4 as a flux are used as raw materials. After firing, the general formula % formula % However, 0 < u < 0.15. 0.03 < V
< 0.3, the manufacturing method includes a first step of mixing an Sr compound, a Ca compound, and an Sb compound and firing the mixture in air at 800°C to 1000°C, and pulverizing the fired product. a second step of adding a Mn compound and 7 lux and firing in an oxidizing atmosphere at 1000°C to 1100°C; and after pulverizing the fired product,
The above (Sr, -uCau)+
- Greatly improves the brightness of vMnvSb20g phosphor,
By using the above phosphor, it is possible to obtain a phosphor for a white display tube with less flicker by combining it with a red to yellow phosphor having a color display afterglow property that has less flicker and has higher blue brightness than conventional ones.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the afterglow characteristics of a blue long afterglow phosphor manufactured by the method for manufacturing a phosphor according to the present invention, and FIG. 2 is an emission chromaticity coordinate diagram of the phosphor and display tube described in Examples. Figure 3 shows the luminance Mn of the blue long afterglow phosphor.
It is a figure showing concentration (v) dependence. Representative Patent Attorney Junnosuke Nakamura Figure 1 Figure 2 X Value Figure 3 Mn 3 degrees (V)

Claims (2)

[Claims] 1. Oxides of Sr, Ca, Mn, and Sb, or compounds that can become oxides of the above elements by heating, and K_2SO_4, Rb_2SO_4, as a flux.
General formula (Sr_1_-_uCa_u)_1_-_vMn_vS which is fired with at least one compound of Na_2SO_4 and Cs_2SO_4 as a raw material
b_2O_6 However, 0≦u≦0.15, 0.03≦v
≦0.3, the manufacturing method includes a first step of mixing an Sr compound, a Ca compound, and an Sb compound and firing the mixture in air at 800°C to 1000°C, and pulverizing the fired product. a second step of adding the Mn compound and flux and firing in an oxidizing atmosphere at 1000°C to 1100°C; and after pulverizing the fired product, heating at 1150°C.
A method for producing a phosphor, comprising a third step of firing in an oxidizing atmosphere at a temperature of 1250°C to 1250°C. 2. The method for producing a phosphor according to claim 1, wherein the Mn compound is Mn_2P_2O_7.