JPS6039312B2 - Method for producing europium activated stannic oxide phosphor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a stannic oxide photoreceptor with europium, and aims to provide a method capable of producing a brighter stannic oxide photoreceptor. .

The europium-activated stannic oxide Sn02:Eu crab photoreceptor is
The only conventionally known low-speed electron beam disc light body Zn○:Z
Unlike the bluish-green light emitted by n, it emits red light with an emission spectrum as shown in FIG.

By using this crab light material, it is possible to make character display tubes multicolored, and its value is great as it can be used for digital displays in various devices that have become popular in many fields in recent years.

Furthermore, it has ample possibility of being used as a red crab light body for a flat color display. The present invention is directed to this europium-activated stannic oxide photoreceptor (hereinafter Sn02:E
In order to give the U-Crab light object (referred to as the "U-Crab Light Body") more practical value, we devised a manufacturing method and improved its brightness. Conventionally, Sn02:Eu nectar was produced by adding aqueous ammonia to a mixed aqueous solution of stannous chloride and europium chloride until the pH reached 8.5 to obtain a hydroxide coprecipitate, and then drying it. , obtained by heat treatment.

This hydroxide has a small particle size of 0.01 mm, making it difficult to manufacture, and also easily converts to Su0 when dried.
It has the disadvantage that it easily changes to 2 and loses its reaction activity during subsequent heat treatment. Therefore, the brightness of the crab photoreceptor that was finally obtained could not be said to be sufficient. Also,
A method of creating an oxalate coprecipitate and thermally decomposing it has also been attempted. However, because the tin and europium mixed solution is rapidly mixed with the oxalate ion aqueous solution, the resulting precipitated particles become dendrites and exhibit a blow-up phenomenon during subsequent thermal decomposition, resulting in a decrease in the brightness of the resulting halo. was low. In the method of the present invention, at least one of stannous halides and sulfates and 1×10−2 to 10
Methyl oxalate or ethyl oxalate is added to a small solution mixed with atomic percent europium, heated and uniformly formed into an oxalate co-pilot by the precipitation method, which is then thermally decomposed. The idea is to obtain a Sn02:Eu crab photoreceptor by heating at a high temperature.

According to this method, an oxalate coprecipitate of tin and europium has good crystallinity, and as is clear from the examples, a brightly emitting crab phosphor can be obtained. Hereinafter, the details will be explained by giving examples. europium oxide,
Weigh the proportions of 1 x 10-2 to 15 atomic % based on tin, and add the specified hydrochloric acid HCIIO to 50 c.
c, and further diluted each with pure water,
Approximately 500 cc of solutions with different europium contents were made.

Add 0.5 of SnC12・2board0 to each of these solutions.
The solution was dissolved in moles (112.8 grams) and further diluted with pure water to make a total volume of 1000 cc, and at the same time, 5 grams of tin metal particles were added in order to prevent the hydrolysis of stannous chloride. Each mixed solution was transferred together with tin metal particles into a 2-capacity, 3-necked round flask. Next, diethyl oxalate (
1 mole (146.1 grams) each of C2&)2C204
I put it in a flask one by one. This is (C2 public) 2C20
40 SnC120 ratio 0 → 2C2 days 50H+SnC205
This is twice the amount of (C2day3)2C204 required for the reaction of 12HCI. The amount of diethyl oxalate should be greater than the reaction equivalent with Sn. This mixed solution of stannous chloride, europium chloride and diethyl oxalate was heated and reacted using a synthesis apparatus as shown in FIG. In the figure, 1 and 2 are three-necked round flasks.

The temperature of the solution in the flask 1 is controlled using a mantle heater 2 and a magcon thermoregulator 3 and a sensitive relay 4. The solution is strongly heated by a motor 7 in a Teflon light fixture 5 with a seal. Furthermore, a Liebig condenser 8 was attached to the flask 1 as a reflux device, and cooling water was passed therein to effect reflux and prevent evaporation loss of the solution. In order to study the reaction temperature and time in advance, we added 2 times the reaction equivalent of diethyl oxalate to a stannous chloride solution containing 1 at% europium. The yield of the next product was measured and investigated.

The results are shown in Table 1. As is clear from Table 1, the hydrolysis reaction (C2Q)2C204 of jetyl oxalate up to 70q0 is insufficient for 201 x 2 days 50H 10 days 2C204, and as a result, the yield is low even with a reaction time of 1 hour. was less than 15%.

Moreover, the reaction time is 0.0% even at a temperature of 80 to 100°C. Immediate yield is 50% or less, and at least 1 hour is required to obtain a yield of 60% or more. Therefore, the appropriate reaction temperature,
The time is 1 hour or more at 80 to 100°C.
The upper limit of the reaction time will be somewhat longer depending on the volume of the reactants, but it should be selected appropriately at a time that will give almost 100% yield.
A long reaction time does not harm the properties of the precipitate and is not a limiting condition. A reaction temperature of 100q0 or more is difficult to achieve because fruit berries are an aqueous solution, and there is no advantage in industrial production.

As described above, the methacrylate coprecipitate obtained by reacting at 80 to 100 qo for over 1 hour showed particles of good crystallinity with well-developed crystal planes that are characteristic of the homogeneous precipitation method.

FIG. 3 shows an electron micrograph of an oxalate coprecipitate containing 1% europium obtained by reacting at 90 qo for 3 hours.

Crystal particles with a maximum diameter of 70 to 80 m were obtained.

Next, for each stannous chloride and chloride solution containing 1 x 10-2 to 15 at% europium, all 9
000 for 3 hours to prepare an oxalate co-precipitate. The precipitate was filtered, washed and dried at 150 qo. After drying, oxalate was thermally decomposed.

Thermal decomposition was carried out in a quartz container without a lid for 2 hours at a temperature of 300 to 100,000 to improve contact with air. Differential heat and thermogravimetric analysis revealed that the heat distribution was 3.
It was confirmed that this occurs rapidly between 00 and 400 qo. Therefore, it is practical to set the thermal decomposition to 400 oo or more. The thermal decomposition time varies depending on the amount of sample, but a temperature lower than 400° C. requires a very long time, which is unfavorable in terms of production. In the case of 0.5 mol of tin oxalate, 400 oo for 4 hours is sufficient.

Considering the heat resistance temperature of the quartz container, the thermal decomposition temperature is 10
It is better not to exceed 00:00. This decomposition process is 300~
400 oo, a rapid exothermic reaction occurs due to combustion of the decomposition product carbon monoxide and oxidation to stannous or stannous. For this reason, the material of the container is preferably quartz, as porcelain containers often break due to thermal shock. For this reason, pyrolysis is carried out using a quartz container.
It is preferable to carry out the process in a temperature range of 00 to 1000 CO.

When the quartz container is used only a few times, the thermal decomposition of the sputum salt can be followed by a heat treatment to diffuse europium into the tin oxide. However, considering the heat resistance of the quartz container, this is not very desirable, and it is better to transfer it to an alumina rubbo with a lid and then perform the europium diffusion treatment on the tin oxide. The heat treatment temperature for the diffusion is 1200 oo or more, and the diffusion time is 2
It was set as 1 kashi period. As a result, various tin oxide saddle photons with different europium contents were created. Furthermore, S
Sn0 was prepared in the same manner as described above, using SnBr2/SnS04 instead of nC12/20, or using dimethyl oxalate instead of diethyl oxalate.
2: An Eu crab photobody was produced.

A slow electron beam excitation device as shown in FIG. 4 was constructed using the Sn02:Eu crab photons produced as described above, and the light emission of each crab photon was investigated. In the figure, reference numeral 21 denotes a glass plate having a transparent electrode 22, on which a light-transmitting film 23 was formed by coating. The amount of crab photoreceptor applied was 3 mg/ml. Reference numeral 24 is a mica board, which has a 5×5 hole opening 24' in its center.

This entrance part 24' is arranged parallel to the glass plate 21 so as to be located in front of the crab light film 23. A grid 25 has a honeycomb structure as shown in FIG. 5, and is arranged in parallel in front of the mica plate 24.

26 is a thermionic emission heater. These components are sealed in a vacuum glass container 27. In such a device, the grid voltage Ec is 18V and the filament voltage E. " was set to 3.0V.Anode electric Pb was set to 10V
The crab light film 23 was excited and the brightness of each crab light body was compared. The excitation current is 1. &hA/, so it is constant. The results are shown in Table 2 along with the manufacturing conditions.

Samples 1 to 6 in Table 21 show the effect of the amount of europium added.

It can be seen that all of these have a brightness of 19 foot-Lamberts or more, and in particular, samples 2 to 5 emit a very bright red light color of 25 foot-Lamberts or more. When the amount of europium added is small, the brightness of the phosphor's light emission decreases, and when it is too large, the brightness also tends to decrease. Therefore, the appropriate amount of europium to be added is 5 x 10-2 to 10 atomic % based on tin. Sample 7~
10 shows the effect of the decomposition temperature of the precipitate. As the decomposition temperature decreases, the brightness of the crab photophores decreases, and 3500
0 required 2 field hours to obtain a 25 foot lambert crab photore. In industrial implementation, the decomposition temperature is 4
It is desirable to set it to 00q0 or more. Considering the heat shock caused by the rapid exothermic reaction during decomposition, a container made of quartz is used. When using a quartz container, the upper limit of the decomposition temperature is preferably 100,000. Sample 11~
14 shows the effect of heat treatment temperature on diffusing europium into the tin oxide matrix. It can be seen that the higher the heat treatment temperature, the brighter the light emitted by the crab phosphor. To obtain a brightness of 25 foot lamberts or more, 120,000 is insufficient and 1250 qo or more is required.

However, in producing the powdered light material, the temperature is set so that tin oxide does not melt. Samples 15 and 16 show cases in which other halides and sulfates were used as tin raw materials, respectively. It can be seen that crab phosphors with excellent luminescence can still be obtained. Sample 17 shows a case in which dimethyl oxalate, which has almost the same potency and effect as diethyl oxalate, is used. This achieved a similar effect. Samples 18 and 19 are conventional examples and are shown for comparative reference.
As explained above, by the manufacturing method of the Sn02:Eu crab photoreceptor of the present invention, it is possible to obtain a crab photoreceptor that is brighter than that of the conventional honey photoreceptor, which has a brightness of at most 16 flat parts. Can be done. Therefore, it is clear that the practicality of a crab light display device that emits red light can be further improved by using the crab light body obtained by the method of the present invention.

[Brief explanation of drawings]

Figure 1 is a diagram showing the electron beam emission spectrum of europium-activated stannic Sn02:Eu nectar, Figure 2 is a diagram showing a synthesis apparatus for tin and europium oxalate co-pillar by uniform precipitation method, Figure 3 is an electron micrograph of tin-europium oxalate conjugate crystal particles obtained by the homogeneous precipitation method, Figure 4 is a cross-sectional view of a slow electron beam excitation device using a Sn02:Eu crystal, FIG. 5 is a diagram showing the structure of a grid used in the above-mentioned slow electron beam excitation device. 1... Flask, 22... Crab light body, 26... Heater for thermionic emission. Figure 1 Figure 4 Figure 2 Figure 3 Figure 5

Claims (1)

[Scope of Claims] 1. Dimethyl oxalate or Diethyl oxalate is added and heated to obtain a tin europium oxalate coprecipitate by a homogeneous precipitation method, which is then thermally decomposed and further heated at a temperature higher than the thermal decomposition temperature to produce tin oxide. A method for producing a europium-activated tin oxide phosphor, which comprises diffusing europium into a ditin matrix. 2. The europium-activated stannic oxide phosphor according to claim 1, wherein the heating to obtain the tin-europium oxalate coprecipitate is carried out in a temperature range of 80 to 100°C. Production method. 3 Thermal decomposition of tin europium oxalate coprecipitate
A method for producing a europium-activated stannic oxide phosphor according to claim 1, characterized in that the process is carried out at a temperature in the range of -1000C. 4. Europium activated oxidation according to claim 1, characterized in that the heating for diffusing europium into the stannic oxide matrix is carried out at 1250°C or higher and within a temperature range in which the stannic oxide does not melt. A method for producing a second tin phosphor.