JP2000290649A - Fluorescent substance, its production, and color cathode ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a fluorescent substance with little reduction in emission efficiency even under a condition severe in excitation conditions and environmental temperatures of a fluorescent film and used for color cathode ray tubes excellent in emitting characteristics by specifying the ratio of the integrated intensity of a thermoluminescent intensity curve before and after the heat treatment. SOLUTION: In the fluorescent substance, the ratio (I1/I2) of the integrated intensity (I1) of a thermoluminescence intensity curve in the temperature range of 80-400 K measured in an inactive gas before the heat treatment by bringing europium as an emission center and oxygen and sulfur as basic structural elements and the integrated intensity (I2) of a thermoluminescence intensity curve in the temperature range of 80-400 K after 1 hour heat treatment at 850-1150 deg.C in an atmosphere containing <0.2 vol.% of oxygen in the aforesaid active gas is brought to <=0.8. To obtain the subject fluorescent substance, it is preferable to have a previous processing and a post-processing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phosphor for a color cathode ray tube having excellent light emission characteristics, a method for producing the same, and a color cathode ray tube formed with a phosphor film using the phosphor.

[0002]

_2. Description of the Related Art A phosphor using yttrium oxysulfide (Y ₂ O ₂ S) as a host crystal is one of well-known materials.
Among them, europium-activated yttrium oxysulfide (Y ₂ O ₂ S:
Eu ³⁺ ) is used as a red phosphor in a direct-view cathode ray tube. A technique for synthesizing the phosphor of this material and a description as a phosphor for color TV are described in, for example, 166 of Phosphor Handbook (edited by Phosphors Society of Japan, Ohmsha Publishing, 1987)
-180 pages and 254-283 pages. As described in the phosphor handbook, the europium-activated yttrium oxysulfide (Y ₂ O ₂ S:
In the case of Eu ³⁺ ) phosphor, a trace amount of rare earth ions, specifically terbium (Tb
³⁺ ) or praseodymium (Pr ³⁺ ).
In addition, the phosphor handbook includes a samarium ion (Sm) in order to lower the Eu ³⁺ concentration and deepen the emission color tone.
^The addition of ³⁺ ) is also described.

[0003]

As described above, europium-activated yttrium oxysulfide (Y ₂ O ₂ S: Eu ³⁺ ) has many uses as a red phosphor for a direct-view color cathode ray tube. However, since the excitation current density of the phosphor increases as the display image of the cathode ray tube increases in definition and contrast, the decrease in luminous efficiency due to luminance saturation and the temperature rise of the phosphor film, so-called temperature quenching, is remarkable. Disadvantages.
As a result, there is a problem that the quality of the display image of the cathode ray tube is reduced.

[0004] A first object of the present invention is to provide a phosphor which has a small decrease in luminous efficiency even under conditions of exciting the fluorescent film and under severe environmental temperature.

[0005] A second object of the present invention is to provide a method for producing a phosphor with a small decrease in the luminous efficiency even under severe conditions of excitation and environmental temperature.

It is a third object of the present invention to provide a cathode ray tube having a high screen luminance provided with a fluorescent film using a phosphor with a small decrease in the luminous efficiency even under the above-mentioned excitation conditions and severe environmental temperatures.

[0007]

(1) The phosphor of the present invention is composed of yttrium, oxygen and sulfur with europium as a light emitting center as a basic constituent element, and is measured before the phosphor is heated in an inert gas atmosphere. Temperature range 80K-400
The integrated intensity (I ₁ ) of the thermoluminescence intensity curve of K and the atmosphere in which the active gas contains less than 0.2 by volume of oxygen,
The ratio (I ₂ / I ₁ ) to the integrated intensity (I ₂ ) of the thermoluminescence intensity curve in a temperature range of 80 K to 400 K measured after heating for 1 hour at a temperature exceeding 850 ° C. and less than 1150 ° C. is 0.1.
8 or less.

(2) a pretreatment step of heating the phosphor of the present invention, a phosphor containing europium as a light emitting center and containing yttrium, oxygen and sulfur as basic constituent elements in air after mixing the raw materials; And a heat treatment in a gas atmosphere.

In this method for producing a phosphor, the inert gas contains oxygen in the subsequent step, and the volume ratio of oxygen to the inert gas is less than 0.2, preferably 0.002 to 0.002.
0.1 and the heat treatment temperature exceeds 850 ° C. and 1150
It is lower than 900C, preferably 900-1100C.

(3) The color cathode ray tube of the present invention comprises a face plate having a fluorescent film having red, green, and blue phosphors formed on an inner surface thereof; a color selection electrode disposed in close proximity to the fluorescent film; An electron gun that emits an electron beam toward the fluorescent film, and a deflection yoke that deflects the electron beam, wherein the phosphor has yttrium with europium as a light emission center, oxygen and sulfur as basic constituent elements, and Temperature range 80 measured before heat treatment of phosphor in inert gas atmosphere
An integrated intensity (I ₁ ) of a thermoluminescence intensity curve from K to 400 K;
A temperature range of 80 K to 4 K measured after heating the phosphor for 1 hour at a temperature exceeding 850 ° C. and less than 1150 ° C. in an atmosphere containing less than 0.2 by volume of oxygen in the active gas.
The ratio (I ₂ / I ₁ ) to the integrated intensity (I ₂ ) of the thermoluminescence intensity curve at 00K is 0.8 or less.

The factors that affect the light emission characteristics of the phosphor include:
Defects (traps) in the crystal are mentioned. Since the trap captures electrons or holes, the energy originally transmitted to the light emitting center is consumed by the trap, and as a result, the light emission characteristics are often adversely affected. Therefore, it is considered that the deterioration of the phosphor is deeply related to the trap density in the crystal. The inventor of the present invention considered as follows. In the case of a phosphor containing oxygen as a constituent element, it is considered that oxygen vacancies are formed during the synthesis of the phosphor, and the oxygen vacancies often serve as traps. In addition, when the europium-activated yttrium oxysulfide (Y ₂ O ₂ S: Eu ³⁺ ) was heat-treated in a stream of hydrogen, discoloration of the matrix was observed. It is considered that oxygen vacancies were formed in the matrix during the heat treatment. Was. Therefore, it has been considered that the emission characteristics of the phosphor can be improved by preventing the formation of the oxygen vacancies and by repairing and eliminating the generated oxygen vacancies. From this point of view, the present invention has solved this problem by a heat treatment process performed after the phosphor is synthesized. However, it is not sufficient to simply heat-treat the phosphor in an oxygen stream to supplement oxygen. For example, the host crystal
In the case of Y ₂ O ₂ S, when the oxygen concentration is high, sulfate ions (SO ₄ ^2- ) are generated during the heat treatment, and when the oxidation proceeds further, the oxide (Y
₂ O ₃ ). Therefore, it is important to precisely control the oxidation state of the phosphor. In the present invention, the heat treatment was performed while paying attention to the oxygen content in the argon (Ar) gas. As a matter of course, it is also possible to use an inert gas such as neon mixed with a desired concentration of oxygen gas instead of argon. In addition, since oxygen vacancies are generated because the phosphor is an oxysulfide, the same applies to a base material in which part of yttrium (Y) is replaced with another ion, such as lanthanum (La) or gadolinium (Gd). The effect can be expected. In the present invention, europium-activated yttrium oxysulfide (Y ₂ O ₂ S: Eu ³⁺ ), which is widely used as a red phosphor, will be described, but a light-emitting center other than Eu ³⁺ , such as praseodymium (Pr ³⁺ ) The same applies to the above oxysulfide phosphor.

As a method for measuring the depth of the trap and the density of electrons and holes (hereinafter, these are referred to as carriers) captured by the trap, thermoluminescence (thermoluminescenc) is used.
e) A method of using a phenomenon as a measurement probe is known. The thermoluminescence is a phenomenon in which the carrier trapped in the trap is thermally opened by raising the temperature of the sample after the excitation is stopped, and the carrier is radiated again by radiative recombination at the luminescence center. Therefore, the more the carriers captured by the trap, that is, the higher the trap density, the higher the thermoluminescence intensity. In the present invention, the intensity of thermoluminescence is measured under a condition of a constant heating rate controlled with high accuracy, and a thermoluminescence curve (glow curve) displayed as a function of the thermoluminescence intensity with respect to the sample temperature is used as a means for evaluating the trap. The test piece used for the measurement was obtained by uniformly coating a phosphor sample on a Ni-plated oxygen-free copper substrate by coagulation sedimentation using water glass. The membrane weight is 4.5
The amount of sedimentation was controlled to be around mg / cm ² . In this measurement method, since the same amount and the same area of the fluorescent film sample can be used, the relative comparison of different samples can be easily performed. The measuring device is the Journal of Electrochemical Society, 14
5, pages 1, 270 (1998). It measured by the following procedures. (1) The sample set in the cryostat was irradiated with ultraviolet rays (wavelength: 254 nm) at a low temperature of about 80 K for 1 hour to capture carriers in the trap. (2) Stop irradiation of ultraviolet rays
After leaving the sample at about 80K for a minute, the sample was heated at a constant speed (0.1K per second). At this time, even when the temperature was raised at a low temperature of 100 K or less, the heating rate was controlled with an accuracy of 0.1% or less with respect to the set temperature. (3) The sample temperature was measured with a K-type thermocouple, and the thermoluminescence intensity was monitored using a photomultiplier tube (R268, manufactured by Hamamatsu Photonics), and the thermoluminescence intensity and the temperature were plotted.

For convenience of explanation, a glow curve 11 of a europium-activated yttrium oxysulfide (Y ₂ O ₂ S: Eu ³⁺ ) phosphor sample obtained in Example 1 described later is shown in FIG. For comparison, the glow curve 12 of the sample (comparative example 1) in which the heat treatment after the synthesis was not performed is also shown in FIG. In the phosphor obtained in the present invention, the thermoluminescence intensity is significantly reduced as compared with the comparative example measured under the same conditions, and it can be seen that the density of harmful traps in the crystal is reduced. When the phosphor of the present invention is compared with the comparative example in the area surrounded by the abscissa and the thermoluminescence curve in the sample temperature range of 80 K to 400 K, that is, the integrated intensity (I ₂ ) of the phosphor of the present invention is comparative. Example integrated intensity (I ₁ )
About 43% of the total. When this integrated intensity ratio is used as a scale, it is desirable to reduce the trap density to 80% or less in consideration of the expression effect of luminance described later.

In the embodiment of the present invention, an area 40 is mainly used to quantitatively express the luminous intensity of the phosphor mainly excited by the electron beam.
X 30 mm ² was irradiated with an electron beam accelerated at 30 kV at a predetermined current amount, and the emission intensity of each sample was compared. The measuring device is the Journal of Electrochemical Society, 143
Volume 5, page 1684 (1996) was used. The emission intensity of the fluorescent film was measured using a colorimeter (CS100, manufactured by Minolta). Further, the irradiation current dependency of the luminance was measured while changing the irradiation current, and the extension of the luminance with the increase of the irradiation current was evaluated by the current coefficient. In the present invention, the current coefficient was calculated according to the following procedure. First, under the same conditions as the above-mentioned acceleration voltage and irradiation area, the electron beam irradiation current was set to 0.5.
5, 0.7, 1.0, 1.2, 1.5, 2.0, 3.0, 5.
The luminance was measured in each case, and the common logarithm of the current was plotted on the horizontal axis, and the common logarithm of the luminance was plotted on the vertical axis. The log-log plot is conveniently fitted to a cubic curve using least squares approximation, and the slope of the curve at a current of 1.2 μA is determined from its derivative. As the current coefficient thus obtained is closer to 1, the light emission intensity increases in proportion to the amount of current applied, which is preferable as the light emission characteristics of the phosphor. In other words, if the current coefficient is lower than 1, even if the irradiation current is increased, the increase in luminance is slowed down, so that high luminance cannot be realized.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings.

(Examples 1 to 4) 10.861 g of yttrium oxide (Y ₂ O ₃ ) having a purity of 99.999% or more and a purity of 99.999% or more were obtained.
0.669 g of 99% or more europium oxide (Eu ₂ O ₃ ) was mixed with a small amount of ethanol in an agate mortar.
Note that yttrium oxide (Y ₂ O ₃ ) was coprecipitated with terbium (Tb) so as to contain a predetermined amount. Purity 99.99
% Of samarium oxide (Sm ₂ O ₃ ) was dissolved in nitric acid (HNO ₃ ) by heating to prepare a solution containing 1 mg of samarium (Sm) in 1 ml of an aqueous solution. This samarium (Sm)
Was added to the above mortar using an aqueous solution pipette so as to have a desired addition concentration, and mixed. This raw material mixture was dried in air at about 120 ° C. for about 1 hour. This mixture, 3.413 g of sulfur flower having a purity of 99% or more, and 99.99 purity
% Of sodium carbonate (Na ₂ CO ₃ ) (3.413 g) and potassium phosphate (K ₃ PO ₄ ) of 98% or more (0.923 g) are mixed well, then put in an alumina crucible and placed in an air crucible.
Heat treatment was performed at 0 ° C. for 2 hours. At this time, the alumina crucible was covered with a lid, and the crucible and the lid were sealed with Aron Ceramic (trade name of Toa Gosei Chemical Co., Ltd.) and were shielded from the outside air. The resulting product is first washed twice with water, then passed through a polyamide resin mesh (opening of about 60 μm square) as it is, and then subjected to about 1 mol / l hydrochloric acid (HC)
Washing with l) and then washing with pure water were performed three times.
The dried phosphor powder was transferred to an alumina container, and heat-treated in a tubular electric furnace in which the flow rate of argon gas was set at 500 ml / min. Processing conditions are 1000 ° C
And heat treatment for one hour. After cooling, fine ZnO and Al ₂ O ₃ were attached by a so-called sol-gel method in order to further improve the dispersibility of the phosphor particles. After the phosphor particles were filtered off, they were dried at 120 ° C. in air. The compound thus obtained was a phosphor emitting red light, and as a result of observation with a scanning electron microscope (SEM), it was found to be a powder having an average particle size of 5 μm. As a result of measurement by powder X-ray diffraction, the diffraction pattern was found to be ASTM (American Society for Testing and
Materials) and the pattern of Y ₂ O ₂ S published in the data. In addition, inductively coupled plasma mass spectrometry (ICP-MS, InP
As a result of analysis using inductively coupled Argon Plasma Mass Spectroscopy), the concentration of impurities contained in 1 g of the phosphor was an analysis value that matched the concentration of the charged substance within an error range. It is considered that the intentionally added trace component is almost taken into the phosphor crystal. The phosphor sample thus obtained was uniformly applied on a Ni-plated oxygen-free copper substrate by a coagulation sedimentation method using water glass to prepare a test piece for evaluating the light emission characteristics of the phosphor.

FIG. 1 shows a thermoluminescence curve 11 of the phosphor of this embodiment.
And a thermoluminescence curve 12 of a sample not subjected to heat treatment after synthesis as Comparative Example 1. From FIG. 1, it can be seen that since the phosphor of this example was subjected to heat treatment after synthesis, the trap density in the phosphor was reduced. In order to make a quantitative comparison, the integrated intensity of the thermoluminescence curve in the measurement temperature range from 80 K to 400 K was compared with the phosphor of the present example and Comparative Example 1
Is 0.43: 1, and the trap density in the phosphor of the present example is smaller than that of Comparative Example 1.

The emission intensity by electron beam excitation at room temperature (300 K) was examined using the above-mentioned measuring apparatus (acceleration voltage: 30 kV, irradiation current: 1.2 μA, irradiation area: 40 × 30 mm ² , irradiation area The current per unit is 0.1μ
A / cm ² ). Table 1 shows the measurement results.

[0019]

[Table 1]

When the phosphor of this embodiment is compared with a sample in which no heat treatment is performed after the synthesis (Comparative Example 1), the brightness of the phosphor sample obtained in this embodiment is about 5% higher. The comparison between the two was also performed using the above-described current coefficient as an index. The heat-treated phosphor of the present example shows a value approximately 2% higher than that of Comparative Example 1, indicating that the degree of luminance saturation is smaller.

A phosphor was synthesized in the same manner as in Example 1,
Samples in which only the temperature conditions of the heat treatment in the argon gas stream after the synthesis were changed were prepared as Examples 2 to 4. In the same manner as in Example 1, a test piece for evaluation was prepared, and a thermoluminescence curve was measured, and the luminance and current coefficient of the sample were measured. FIG. 2 and Table 2 show the measurement results together with Example 1 described above.

[0022]

[Table 2]

In FIG. 2, reference numerals 11, 21, 22, 2
3 is Example 1, Example 2, Example 3, and Example 4 respectively.
The reference numeral 12 indicates the thermoluminescence curve of Comparative Example 1. As shown in FIG. 2, the phosphor sample of Example 1 heat-treated at 1000 ° C. has the lowest thermoluminescence intensity. That is, the sample of Example 1 has a small defect density in the crystal and is excellent. Comparative Example 1 and Example 2 as in Example 1.
When the integrated intensity ratios of the thermoluminescence curves of Comparative Examples 1 to 4 were determined, Examples 2, 3 and 4 were 80% and 71% of Comparative Example 1 respectively.
And 66%. As shown in Table 2, the sample of Example 1 heat-treated at 1000 ° C. showed the highest luminance. The luminances of the samples manufactured in the same manner as Comparative Examples 2 and 3 except that only the heat treatment temperature was set to 850 ° C. and 1150 ° C. were almost the same as those of Comparative Example 1 not subjected to the heat treatment. Further, the current coefficient value has a tendency similar to the luminance, that is, an example in which the heat treatment is performed at 1000 ° C.
The sample No. 4 shows the highest current coefficient, and it is not preferable that the processing temperature is too low or too high. From these experimental results,
It became clear that the heat treatment temperature greatly contributed to the improvement of the light emission characteristics of the phosphor. The heat treatment temperature range of the phosphor is 8
In the range above 50 ° C. and below 1150 ° C., preferably 9
It turns out that the range of 00 ° C to 1100 ° C is good.

As described above, the europium-activated yttrium oxysulfide (Y ₂ O ₂ S: Eu) of this embodiment represented by the first embodiment
³⁺ ) The phosphor has a significantly reduced defect density compared to the untreated one by performing a heat treatment in a controlled atmosphere, and has about 5% higher luminance and about 2% higher current coefficient. .

(Examples 5 to 8) Samples in which a phosphor was synthesized in the same manner as in Example 1, the heat treatment temperature in the stream of argon gas after synthesis was 1000 ° C, and only the mixing ratio of oxygen to argon gas was changed. Were produced as Examples 5 to 8. In this series of experiments, the amount of oxygen contained in a trace amount of argon gas was reduced to 0.1% or less through a purifier, and thereafter, a predetermined amount of oxygen was mixed. The mixing ratio of oxygen / argon was a volume ratio obtained from the flow ratio. In the same manner as in Example 1, a test piece for evaluation was prepared, and a thermoluminescence curve was measured, and the luminance and current coefficient of the sample were measured. The measurement results are shown in FIG.

[0026]

[Table 3]

In FIG. 3, reference numerals 31, 32, 33, 3
4 is Example 5, Example 6, Example 7, and Example 8 respectively.
The reference numeral 12 indicates the thermoluminescence curve of Comparative Example 1. As shown in the thermoluminescence curve of FIG. 3, the sample of Example 8 heat-treated at a mixing ratio of oxygen / argon of 0.05 showed the lowest thermoluminescence intensity, indicating that the defect density in the crystal was small. . As in Examples 1 to 4, when the integrated intensity of the thermoluminescence curve was compared with Comparative Example 1, Examples 5, 6, 7, and 8 were compared.
Were 77%, 66%, 43% and 54%, respectively. Also, from the relative luminance data shown in Table 3, the sample of Example 7 which was heat-treated at a mixing ratio of oxygen / argon of 0.050 also showed the highest luminance. The brightness of the samples manufactured simultaneously as Comparative Examples 4 and 5 was equal to or lower than that of Comparative Example 1 which was not subjected to the heat treatment, and the effect of the heat treatment was not exhibited. Looking at the value of the current coefficient, the result was similar to the tendency of the luminance. From these results, it is understood that the oxygen concentration in the atmosphere at the time of the heat treatment greatly contributes to the improvement of the emission characteristics, and the mixing ratio of oxygen / argon is preferably 0.002 to 0.1.

As described above, as shown in Examples 5 to 8, the europium-activated yttrium oxysulfide (Y ₂ O ₂ S: Eu ³⁺ ) phosphor was used in an atmosphere in which the mixture ratio of oxygen / argon was controlled. Comparative Example 1 in which no heat treatment was performed by performing heat treatment
The defect density is greatly reduced compared to the phosphor of
%, And the current coefficient can be increased by about 2%.

(Embodiment 9) Using a cathode ray tube (21 inch color display tube) as a typical image receiving device, the following study was conducted. The phosphor materials were the red phosphor (Y ₂ O ₂ S: Eu ³⁺ ) obtained in Example 1 above, a commercially available blue phosphor with a pigment (ZnS: Ag, Cl) and a green phosphor (ZnS: Cu). , Al). In addition, the phosphor of the comparative example (without heat treatment) was separately manufactured and similarly evaluated. Here, the fluorescent film was formed so as to have a film weight of about 3.5 mg / cm ² by a slurry method (using polyvinyl alcohol and sodium bichromate) generally used for the manufacture of a cathode ray tube. FIG. 4 shows a schematic view of a cross section of the produced cathode ray tube. The fluorescent film 41 is formed on the face plate 42. Here, the fluorescent film is formed such that red, green, and blue phosphors are divided into gaps in the black matrix 43. Neck tube 44
The electron beam emitted from the electron gun 45 in the deflecting yoke 4
The phosphor is deflected by 6 and passes through a shadow mask 47, which is a color selection electrode, and further passes through an aluminum deposition film 48 to excite a phosphor of a predetermined emission color. Here, the following measurement was performed by adding a signal so as to display only red. The luminance of the phosphor film was 27.5 kV for acceleration voltage and 200 μ for irradiation current.
A, Measurement was performed with an irradiation area of 427 × 320 mm ² . The current per irradiation area is about 0.15 μA / cm ² . Table 4 shows the measurement results of the luminance.

[0030]

[Table 4]

In comparison with the color display tube of the present embodiment and the color display tube of Comparative Example 1 in which the phosphor is not subjected to the heat treatment after synthesis (Comparative Example 6), the brightness of the present embodiment is also about 4%. It showed a high value. Comparing the two with the above-described current coefficient, the cathode ray tube of the present embodiment subjected to the heat treatment shows a higher value of about 2%, indicating that the degree of luminance saturation is smaller.

According to the above embodiment, the heat treatment is performed in an atmosphere having a specific oxygen concentration after the synthesis of the phosphor to reduce the trap density in the phosphor crystal. As a result, the luminance of the phosphor is reduced by about 5% and the current coefficient is reduced. It was found that it could be increased by about 2%. Since the brightness of the fluorescent film can be increased, the image quality of the high definition display can be improved. The present invention has been described by taking a color cathode ray tube as an example. However, the present invention is not limited to this, and can be applied to a self-luminous display device that emits a phosphor, for example, a plasma display or a field emission display.

[0033]

According to the present invention, the phosphor obtained by the present invention showed about 5% higher luminance than the phosphor not subjected to the heat treatment. Also,
It has been found that such a phosphor can be easily produced according to the method for producing a phosphor of the present invention. Further, by applying the phosphor of the present invention to a color cathode ray tube, the luminance of the phosphor screen can be increased, and a high-quality image can be displayed.

[Brief description of the drawings]

FIG. 1 is a diagram showing the temperature dependence (glow curve) of the thermal emission intensity of a phosphor of an example of the present invention.

FIG. 2 is a diagram showing the temperature dependence (glow curve) of the thermoluminescence intensity of a sample in which the heat treatment temperature is changed in the phosphor of the present invention.

FIG. 3 is a diagram showing the temperature dependence (glow curve) of the thermoluminescence intensity of the sample of the phosphor of the present invention in which the mixing ratio of argon to oxygen is changed.

FIG. 4 is a schematic partial cross-sectional view of a color cathode ray tube using the phosphor of the present invention for a phosphor film.

[Explanation of symbols]

11% heat-treated sample (Example 1), 12% untreated sample (Comparative Example 1), 21% heat-treated sample at 900 ° C (Example 2), 22 ° -950 ° C heat-treated sample (Example 2) Example 3), a sample heat-treated at 23-1100 ° C. (Example 4), a sample heat-treated at a 31 ° mixing ratio of 0.002 (Example 6), and a sample heat-treated at a 32 ° mixing ratio of 0.01. (Example 7), a sample heat-treated at 33 ° mixing ratio 0.05 (Example 8), a sample heat-treated at 34 ° mixing ratio 0.1 (Example 9), 41 ° fluorescent film, 42 ° {Face plate, 43} Black matrix, 44}
‥ neck tube, 45 ‥‥ electron gun, 46 ‥‥ deflection yoke, 4
7 ‥‥ Shadow mask, 48 蒸 着 Al deposited film.

Claims (5)

[Claims] 1. An integration of a thermoluminescence intensity curve in a temperature range of 80 K to 400 K measured before heat treatment in an inert gas atmosphere in a phosphor containing europium as a light emission center and yttrium, oxygen and sulfur as basic constituent elements. Strength (I ₁ )
And integration of a thermoluminescence intensity curve in a temperature range of 80 K to 400 K measured after heating for 1 hour at a temperature exceeding 850 ° C. and less than 1150 ° C. in an atmosphere containing oxygen in a volume ratio of less than 0.2 in the active gas. Intensity (I ₂ ), and the ratio (I
₂ / I ₁ ) is 0.8 or less. 2. A method for producing a phosphor containing yttrium, oxygen and sulfur as basic constituent elements using europium as a light-emitting center, a pre-process in which raw materials are mixed and a heat treatment in air, and a heating process in an inert gas atmosphere. And a post-processing step. 3. The method for producing a phosphor according to claim 2, wherein the inert gas contains oxygen and the volume ratio of oxygen to the inert gas is less than 0.2. And a heat treatment temperature of more than 850 ° C. and less than 1150 ° C. 4. The method for producing a phosphor according to claim 3, wherein the volume ratio of oxygen contained in the inert gas in the subsequent step is 0.002 to 0.1, and the heat treatment temperature is 900 ° C. ~
A method for producing a phosphor, wherein the temperature is 1100 ° C. 5. A face plate in which a fluorescent film having red, green, and blue phosphors is formed on an inner surface, a color selection electrode disposed close to the fluorescent film, and an electron beam emitted toward the fluorescent film. In a color cathode-ray tube including an electron gun and a deflection yoke for deflecting the electron beam, the phosphor is composed of yttrium, oxygen and sulfur having europium as a light emission center as basic constituent elements, and the phosphor is inert. An integrated intensity (I ₁ ) of a thermoluminescence intensity curve in a temperature range of 80 K to 400 K measured before performing heat treatment in a gas atmosphere; and an atmosphere containing the phosphor in the active gas in a volume ratio of less than 0.2 in oxygen. And the ratio (I ₂ / I ₁ ) to the integrated intensity (I ₂ ) of the thermoluminescence intensity curve in a temperature range of 80 K to 400 K measured after heating at 850 ° C. to less than 1150 ° C. for 1 hour.
Is 0.8 or less.