JPS6042273B2 - filter coated phosphor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention is an improved red emitting europium-activated yttrium oxysulfide Y oxysulfide coated with indium sulfide I horse 53 material for use in cathode ray tube fluorescent surfaces.

O. Regarding S/Eu phosphor. In order to improve the contrast of the image blown onto a color picture tube, a pigment filter layer is provided in front of the phosphor layer, or a pigment filter layer is placed on the surface of the phosphor particles to reduce the reflection of external light on the phosphor surface. It is known to form a fluorescent surface using a filter-coated phosphor coated with pigment filter particles.

For example, JP-A-50-56146 describes the latter phosphor in which pigment filter particles are coated on the surface of the phosphor particles. This filter material exhibits the same color tone with respect to the light emitted by the phosphor used in the fluorescent surface of the color picture tube.

For example, silver, chlorine activated zinc sulfide phosphor ZnS/Ag)Cl
Or silver, aluminum activated zinc sulfide ZnS/AgNAl
In the blue-emitting phosphor of Y, coating with cobalt blue pigment is performed. O. S/Eu red-emitting phosphors are coated with red iron pigment, and both phosphors have been successfully put into practical use for color cathode ray tubes.
The red red pigment used in the red-emitting Y2O2S/EU phosphor here is a pigment with excellent heat resistance, acid resistance, alkali resistance, and hiding power. There are some difficulties.

Therefore, In2s3, which has good heat resistance and excellent color tone, has been selected as a substitute for red red pigment, and a phosphor coated with a filter material based on this In2s3 has been developed. For example, Japanese Patent Application Laid-Open No. 53-137087,
Tokugan Sho 52-13988 Gin Specification, Sho 52-139
89 Gin specification and the like relate to this type of phosphor. Such a red-emitting phosphor coated with InS3 filter material is formed, for example, as follows. Y. O2S/Eu
Indium oxide In2s3 on the surface of the red-emitting phosphor
Or coat with indium hydroxide In2s3.xH2o. This indium compound-coated phosphor is then coated with a carbonate of an alkali metal M such as sodium Na, potassium, or rubidium Rb. and sulfur S are mixed, filled into a crucible, fired at about 900°C, and then treated with water. As a result, indium sulfide alkali sulfide In2S3・N
An M2S coated Y2O2S/EU phosphor is obtained. This is heat treated and converted to indium sulfide alkali sulfate l)1 S3・N
A M2sO4 coated Y2O2S/EU phosphor is formed. In this example, when coating with In2s3 alone, the heat resistance is poor; for example, during the tube manufacturing process at 350°C to 500°C, a part of In2s3 is oxidized to In2O3 and the body color fades. I end up. For this reason, ■A single coating of N2s3 is eliminated, and a composite compound with M2S is coated, and M2S is converted into M2SO4 by heat treatment.
This serves as a protective film for In2s3 and prevents oxidation. I
When the n2s3.NM2sO4 coated Y2O2S/EU phosphor is used in the phosphor film of a color cathode ray tube, it provides approximately the same luminance S with the same contrast as the red iron phosphor. However, the spectral reflectance is different. For example, at long wavelengths, especially at long wavelengths of 600 r1 m or more, the former composite compound-coated phosphor is higher than the latter red iron oxide-coated phosphor, whereas at short wavelengths, especially at short wavelengths of 50,011 m or less, the former is lower. Since the emission spectrum peak of the Y2O2S/EU phosphor is 62611 m, the emission spectrum peak portion of the former composite compound coated phosphor is cut by a filter material of In2s3・M2sO4, but the latter red iron oxide coated phosphor The luminance is increased because it requires less light compared to the body. Although this difference is recognized in the emission brightness characteristics of the fluorescent powder, this difference in brightness cannot be obtained in the tube characteristics. Therefore, this composite compound-coated fluorescent film has the disadvantage that the excellent characteristics of the spectral reflectance curve cannot be fully utilized.

The present invention aims to provide a red-emitting phosphor coated with an Ins3-based filter, which is improved by changing the Ins3-based filter material coating method to obtain a phosphor film with high luminance and good contrast. be.

That is, the present invention provides (1) a filter-coated phosphor consisting of a red-emitting Y2O2S/EU phosphor and an Ins3-based filter material covering the surface of the phosphor;
2s3 is a complex sulfate of Na and Cs (Na, CS) 2S0
The filter-coated phosphor whose surface is coated with 4 or (2) composite sulfate has a weight ratio of 0.05 to 0.17 between Na (the sum of 5Cs and 1N), and Cs and 1N. N
The filter-coated phosphor according to (1) above is a composite sulfate having a weight ratio of 0.005 to 0.05. In this invention, the red light emitting phosphor is Y2O. S/Eu.

First, the Y2O2S/EU phosphor particles were dispersed in deionized water, and then In2s3, which was well dispersed by a ball mill, was added to the Y2O2S/EU phosphor particles.
Add and mix. Next, an acrylic emulsion resin is added, and the hydrogen ion concentration is lowered with dilute sulfuric acid to cause In2s3 to adhere to the surface of the phosphor. Then, after offshore drying, S
For example, Na2cO3 and cesium carbonate CS2CO3 are mixed, filled into a silica crucible, and fired at 900°C for 1 to 2 hours. After washing with water and drying, indium sulfide, sodium sulfide, cesium In2s3.n (Na
, Cs)2S coated Y2O2S/EU phosphor is obtained.
In order to improve the quality of the fluorescent film, the surface may be treated with zinc borate or a water-soluble organic substance such as hydropropyl cellulose. Next, by heat treatment at 350-500℃, indium sulfide, sodium sulfate, cesium Ir]2S
A 3.n(Na,CS)2S04 coated Y2O2S/Eu phosphor is formed. In this phosphor, the filter material is In2
The surface of s3 is protectively coated with (Na,CS)2S04. For example, the melting point of Na2cO3 used to form a protective film on filter material is 851°C? CS2 while there is
The melting point of CO3 is 610°C, and at a firing temperature of 900°C, CS2CO3 evaporates more than Na2cO3.

Therefore, CS2CO3 acts as a flux during this firing, grows protective film crystals, and strengthens this film body.
The filter material 1r12S3●n (Na, CS) 2S04 covering the Y2O2S/EU phosphor with the phosphor of this invention covers the IrL2S3 surface (Na, CS) 2S04 C
The optimum s/Na weight ratio is 0.005 to 0.05.
If it is less than 0.005, a strong protective film cannot be obtained, and In2
Good adhesion of the protective film to the s3 surface cannot be obtained. 0 again
．． When it exceeds 05, the body color of In2s3 cannot be obtained well. At this time, the color tends toward the short wavelength side, making it undesirable as a filter material for red phosphors. The optimum weight ratio of the sum of Na and Cs to In is 0.05 to 0.17. If it is less than 0.05, the protective film will not be effective in preventing discoloration during the heat treatment process of In2s3,
This is because if it exceeds 0.17, the aggregation of the phosphor particles will be strengthened, reducing the dispersibility in the slurry liquid prepared at the time of coating the phosphor, and further reducing the luminance.

Na2sO4 instead of Na2cO3, and CS2CO3
You may use CSNO3 instead.

However, the melting points of both Na and Cs compounds are In2s
3 and (Na,CS)2S lower than the firing temperature during formation,
And the latter is selected and used so that it has a lower melting point. The filter-coated phosphor of the present invention thus obtained has a strong composite sulfate protective film formed on the surface of IIl2S3, and also has good adhesion between In2s3 and Y2O2S/EU phosphor.

For this reason, a fluorescent film formed using this phosphor by coating as a phosphor slurry liquid by a conventional method is dense, and the organic film formed on the surface of the phosphor film is uniform and has no pinholes. body. Therefore, pinholes in the aluminum Ae film formed on this film are reduced and made uniform. Therefore, the luminance is improved by about 10%, and a fluorescent film with good contrast can be provided. The filter-coated phosphor of the example will be described below.

However, the Y2O2S/EU phosphor may have an E yield of 3% to 6% by weight, and in each example, it is 4%.
．． It is constant at 100%. Example (1) 1 kg of Y2O2S/EU phosphor is dispersed in 10 e of deionized water, and then 70 cc of a 1% Irl2S3 dispersion solution prepared by dispersing this well in a ball mill is added and mixed with thorough stirring.

Add an acrylic emulsion solution to this with a zero concentration against the phosphor.
．． After adding 01% by weight and stirring, dilute sulfuric acid H2SO4, pH3
Adjust accordingly. This is filtered and dried. Dry product 1k
g, Na2CO33.3g and CS2CO3l. lg(5
Mix 30g of S and put it in a silica pot and heat it at 900℃ for 8
Gin-yaki. After washing 4 to 5 times with deionized water, the mixture was placed in a pot at a weight ratio of 2 parts of beads, 1 part of deionized water, and 1 part of fluorescent material, and pulverized into powder. After grinding, take out into a container and add deionized water to make a total volume of 10e. 0 for this
．． 9 g of Polax are dissolved in the appropriate amount of deionized water and added. Next, 0.4 mol zinc sulfate ZnsO4 aqueous solution 50
After adding cc and stirring well, let stand. After standing still, the supernatant is drained, and deionized water or deionized water at 50 to 60° C. is added for washing 4 to 5 times. Next, the washed phosphor was placed in a solution of hydropropyl cellulose I (PC6y 3e) dissolved in deionized water, stirred for 1 hour, filtered, and dried. This dried product was passed through a 300 mesh sieve. By sieving with
A coated Y2O2S/EU phosphor is obtained. This phosphor is made of Irl2S3 by heat treatment of the phosphor film in the normal cathode ray tube manufacturing process.
・N(Na,CS)2S04 coated Y2O2S/EU phosphor. A cathode ray tube equipped with a fluorescent film thus formed and an In2s3/Na2sO4 coated Y2O2S
The voltage characteristic curves for a cathode ray tube with a similar phosphor film made of /EU phosphors are illustrated by dotted and solid lines. A phosphor slurry is prepared in a conventional manner using the phosphor thus obtained, and is coated on a cathode ray tube in a conventional manner to form a phosphor film. Emission brightness was improved by 10% compared to a cathode ray tube equipped with a fluorescent film, and contrast was also improved by 3%.

Furthermore, when the protective film of this phosphor was analyzed, the Cs/Na amount ratio was 0.025, and the Na+Cs/In amount ratio was 0.10.
It was hot. Example (2) 1 kg of Y2O2S/EU phosphor is dispersed in deionized water 10e, and In2s3 is mixed in the same manner as in Example (1).

N to this? CO35y<15CS2C031.7y and S
3OV and calcined at 900°C. Hereinafter, I obtained by the same treatment as in Example (1) above
n2S3・n(Na,Cs)2S coating (Y2O2S/E
u) Create a slurry using a phosphor in a conventional manner and apply it on a cathode ray tube panel in a conventional manner to form an In2s3.n(N
a, CS) The cathode ray tube with the 2S04-coated Y2O2S/EU phosphor film had an 8% improvement in luminance and 4% improvement in contrast compared to the cathode ray tube with the conventional phosphor film. or,
The Cs/Na amount ratio confirmed by analysis was 0.027,
The Na+Cs/In ratio was 0.15. Example (
3) 1k9 Y2O2S/EU fluorescer in 10e deionized water
was dispersed and prepared in the same manner as in Example (1) above to obtain IIl2S3.
Mix.

To this, Na2CO33.3y (5CS2C030.4y
(5S30y is mixed and fired at 900°C for 8 minutes. Thereafter, the In2S3.n(Na,Cs)2S coated Y2O2S/
A cathode ray tube equipped with a phosphor film made by creating a slurry using an EU phosphor in a conventional manner and coating it on a cathode ray tube panel in a conventional manner is superior to a cathode ray tube equipped with a fluorescein film of a conventional phosphor. Emission brightness is improved by 8% and contrast is improved by 3%. In addition, the Cs/Na amount ratio confirmed by analysis was 0.008,
The Na+Cs/In amount ratio was 0.101. Example
(4) In6S3・n(Na,
Cs) 2S coated Y2O2S/EU phosphor at 420℃
After heat-treating the Y2O2S/EU phosphor coated with In2s3.n(Na,CS)2S04 for a period of time, a phosphor slurry was prepared using a conventional method, and the resulting phosphor film was applied to a cathode ray tube. , the same effects as in Example (1) can be obtained.

As described above, the phosphor of the present invention has a strong protective film of the filter material that covers it and has good adhesion to the In2s3 surface. To obtain a uniform film, high luminance, and a fluorescent film with excellent contrast.

[Brief explanation of the drawing]

The figure shows the voltage characteristic curves of each phosphor film formed by the conventional phosphor and the embodiment phosphor of the present invention using solid lines and dotted lines.

Claims (1)

[Claims] 1. A filter-coated phosphor comprising a red-emitting europium-activated yttrium oxysulfide phosphor and an indium sulfide filter material covering the surface of the phosphor, wherein the filter material is made of indium sulfide. A filter-coated phosphor characterized in that its surface is coated with a composite sulfate of sodium and cesium. 2 The composite sulfate has a weight ratio of the sum of sodium weight and cesium weight to indium weight of 0.05 to 0.17, and a weight ratio of cesium weight and sodium weight of 0.
．． The filter-coated phosphor according to claim 1, characterized in that the filter-coated phosphor is a complex sulfate having a molecular weight of 0.005 to 0.05.