JPH0625359B2 - Long afterglow phosphor for display - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to a phosphor used as a long afterglow phosphor for a display in a CRT for a color monitor television.

[Prior art]

Recently, a high-definition display color picture tube has been widely used for observation of terminal equipment of computer and system control equipment. The vertical scanning frequency of a normal color television is 60 Hz, but in order to further improve the resolution, a monitor television with high definition increases the horizontal scanning frequency to increase the number of scanning lines. When the horizontal scanning frequency is increased, the video amplifier is required to have a wide frequency characteristic, which is extremely expensive.
When the vertical scanning frequency is lowered, the frequency characteristic of the video amplifier can be narrowed. Therefore, the vertical scanning frequency is usually lowered to about 40 Hz. At this time, in order to prevent the flickering of the screen from occurring, it is necessary that the phosphor forming the fluorescent surface has a long afterglow. As a phosphor satisfying such a condition, P-27 is used as a red phosphor.
_{(Zn 3 (PO 4) 2} : Mn), P-3 as a green phosphor
9 (Zn ₂ SiO ₄ : Mn, As) is known and is in practical use.

[Problems to be Solved by the Invention]

However, no blue phosphor having sufficient afterglow characteristics has been found. Since the blue afterglow phosphor does not have the necessary afterglow characteristics by itself, a mixture of the P-22 blue phosphor with the red long afterglow phosphor and the green long afterglow phosphor, , ZnS, Ag, and Ga, In, Ba, etc. are added to provide afterglow. However, since the former phosphor is a mixed product, there is a problem in the inhomogeneity of the characteristics, and the latter phosphor has the drawbacks of low emission brightness and insufficient afterglow. . The present invention was developed for the purpose of solving this drawback, and an important object of the present invention is to provide a long-lasting display for a display which has sufficient afterglow characteristics and emission brightness and whose emission color can be freely adjusted. It is to provide a fluorescent body.

[Means for Solving the Problems]

The long afterglow phosphor for a display of the present invention has a general formula (M
is _{e 1-ab Mn a Eu b} ) F 2. In this formula, Me
Is at least one of Mg, Ca, Sr, Ba, Zn and Cd. Further, the value of a indicating the content of Mn and the value of b indicating the content of Eu are set in the following ranges. 1 × 10 ⁻⁵ ≦ a ≦ 1 × 10 ⁻¹ 0 <b ≦ 1 × 10 ⁻¹ This long afterglow phosphor has MeF ₂ as a host material and Mn and Eu.
Eu and Mn that are activators
The color tone can be freely changed while maintaining the afterglow property by changing the density of.

【Example】

The phosphor of the present invention can be roughly classified into two methods. In the first method, fluorides or oxides, carbonates, nitrates, sulfates, halides, and the like of each component metal used as raw materials are mixed with fluorides such as NH ₄ F and NaF as a flux and baked. Is the way to do it. The second method is to add HF and NH to a salt solution of each component metal.
_This is a method of firing coprecipitated fluoride of each component obtained by reacting fluoride such as ₄ F and NaF. The conditions for firing these raw materials may be any of an oxidizing atmosphere in air, a reducing atmosphere such as H ₂ and CO, and an HF and NH ₄ F gas stream. 1 to 5 at a temperature of 600 ° C. to 1000 ° C. in this atmosphere
It can be manufactured by firing for an hour. The container used for firing is
Alumina, porcelain and quartz can be used, but alumina is most suitable. After the heating and firing, the firing reaction product was treated by a known means such as a mixer mill or a ball mill. Example 1 CaF ₂ to 50.0 g, ZnF ₂ to 0.30 g, and Mn ₂
O ₃ 0.20 g, Eu ₂ O ₃ 0.50 g, and NH ₄ F 5.0 g were weighed and mixed in a mortar for 3 hours. Medium 950
It was baked at 90 ° C. for 90 minutes. The obtained fired product was cooled and loosened, and then the fired product and glass beads were mixed and crushed in a ball mill for 10 hours, and then phosphor powder was obtained through decoration. Example 2 50.0 g of CaF ₂ was weighed, and Mn ₂ O ₃ was added thereto.
After weighing 20 g, 0.50 g of Eu ₂ O ₃ and 5.0 g of NH ₄ F, they were mixed in a mortar and the resulting mixed powder was placed in an alumina crucible and baked at 950 ° C. for 90 minutes in a reducing atmosphere. did. Then, the same treatment as in Example 1 was performed to obtain a phosphor powder. Example 3 50.0 g of CaF ₂ was weighed, and Eu ₂ O ₃ was added thereto.
10 g, 0.10 g of Mn ₂ O ₃ and 5.0 g of NH ₄ F were weighed and treated under the same conditions as in Example 1 to obtain a phosphor powder. Example 4 50.0 g of CaF ₂ was weighed, and ZnF ₂ was added thereto in an amount of 0.1
0 g, Eu ₂ O ₃ 0.50 g, Mn ₂ O ₃ 0.30 g,
After weighing 5.0 g of NH ₄ F, the same treatment as in Example 1 was carried out to obtain a phosphor powder. Example 5 CaF ₂ 50.0 g, Eu ₂ O ₃ 0.10 g, Mn ₂ O
0.05 g of ₃ and 5.0 g of NH ₄ F were weighed and treated under the same conditions as in Example 1 to obtain a phosphor powder. In Examples 1 to 5, manganese remains almost without being lost in the firing process. Therefore, the Mn activation amount of the phosphors produced in Examples 1 to 5 is about 1 × 10 ^{−3 to} 6 × 10 ⁻³ , where a is 1 × 10 ^{3 with} Ca, Mn, and Eu as 1 as a whole. ^-3 ~
It becomes 6 × 10 ^-3 . Further, in Examples 1 to 5, the activation amount of Eu, that is, b, is
It is about 1 × 10 ^{−3 to} 5 × 10 ⁻³ . In the CIE chromaticity diagram, the phosphor manufactured in Example 1 had an x value of 0.158, ay value of 0.161, and a relative emission intensity Y of 74.6 with respect to the P-22 blue phosphor. %, P-2
2 The blue component emission intensity Z for a blue phosphor is 24.8.
%, The afterglow time at which the emission luminance was 1/10 was 170 ms, which was an excellent characteristic. The phosphor produced in Example 2 has an x value of 0.161, y
The value was 0.113, Y was 51.2%, Z was 25.6%, and the afterglow time was 180 ms. Further, the phosphor produced in Example 3 has an x value of 0.14.
1, y value is 0.201, Y is 52.0%, Z is 13.3
%, The afterglow time was 180 ms. Furthermore, the phosphor produced in Example 4 has an x value of 0.1.
58, y value is 0.208, Y is 76.4%, and Z is 21.
6%, afterglow time was 170 msec. Further, the phosphor produced in Example 5 has an x value of 0.14.
8, y value is 0.144, Y is 36.1%, Z is 13.9.
%, The afterglow time was 180 ms. FIG. 1 shows the emission characteristics with respect to the wavelength of the phosphor manufactured in Example 3. This phosphor has a wavelength of about 420 mμ.
And has two emission peaks of 490 mμ. The relative intensities of the two emission peaks can be adjusted by changing the activation amounts of Eu and Mn. FIG. 2 and FIG. 3 show changes in x value and y value of a fluorescent substance in which Me is Ca and CaF ₂ is a matrix and the activation amounts of Mn and Eu are changed. FIG. 2 shows the activation amount of Eu, that is, the x value and y when the activation amount a of Mn is changed by specifying b in the general formula of the claims to 3 × 10 ^−3. Indicates the change in value. As is clear from this figure, when the activation amount of Mn is increased, the y value increases and the emission color approaches blue-green, and when Mn is decreased, the y value decreases and the emission color shifts to the bluish purple side. It shifts. FIG. 3 shows the activation amount of Mn, that is, a in the general formula is 5 ×
X value when the activation amount of Eu is changed to 10 ^-3 ,
The change in y value is shown. As is clear from this figure, when the activation amount of Eu is increased, the y value is decreased and the emission color is deeper blue, which is contrary to Mn, and when the activation amount of Eu is decreased, y increases. The value increases and the emission color approaches blue-green. E
When the activation amount of u is increased, the x value tends to increase to some extent, but it does not become so large from around the x value = 0.15.
Therefore, the value of b indicating the activation amount of Eu is adjusted to 1 × 10 ⁻¹ or less, preferably 1 × 10 ⁻² or less in consideration of the emission color. That is, in the long afterglow phosphor for a display of the present invention, in the general formula (Me _{1 -ab} Mn ₃ Eu _b ) F ₂ , a and b are specified as the following values. 1 × 10 ⁻⁵ ≦ a ≦ 1 × 10 ⁻¹ 0 <b ≦ 1 × 10 ⁻¹ The maximum values of a and b are determined to be large as compared with the range shown in FIGS. 2 and 3. This is because the x value and the y value do not change so much even if the values of a and b are increased from constant values, as can be seen from the figure. Depending on the application, long afterglow phosphors for displays can be produced within the above ranges. When the activation amount of Mn is zero, the afterglow property is significantly lost. For example, in the present inventors' experiment, CaF ₂ was 50.0%.
g, ZnF ₂ 0.30 g, Eu ₂ O ₃ 0.30 g, M
The phosphor produced by firing the raw material containing 0 g of n ₂ O _{3 and} 5.0 g of NH ₄ F by the method of Example 1 had a very short afterglow time of 8 msec, and had a relatively short afterglow time with respect to P-22. Luminance is also 4.
The characteristic was 6%, which was not practical. However, the general formula of _{(Ca 1-ab Mn a Eu} b) F 2 with phosphor, the range of a 5
When changing from × 10 ^-4 to 5 × 10 ^-2 , the afterglow time is 175 to 180 msec, which is almost unchanged. The value of b can be about 1 × 10 ⁻⁵ depending on the application. When the matrix is CaF ₂ and is used for a long afterglow blue phosphor of a color television, a is 1 × 10 ⁻⁴ to 1 × 10 ⁻² , and b is preferably 0.5 × 10 ⁻³ . It is determined within the range of 1 × 10 ^-2 . FIG. 4 shows the afterglow characteristics of the phosphor produced in Example 3. As is clear from this figure, the phosphor of the example of the present invention had a tenth afterglow time of about 180 ms. Further, a phosphor having Me as Mg was manufactured and its characteristics were measured. This phosphor has a Z content of 50.0 g of MgF _2.
nF ₂ 0.30 g, Eu ₂ O ₃ 0.30 g, Mn ₂ O ₃
Were weighed in an amount of 0.20 g and NH ₄ F was weighed in an amount of 5.0 g, and these raw materials were treated in the same manner as in Example 1. This phosphor exhibited a long afterglow of 700 msec and a relative emission luminance of 131.6%. The emission color of this phosphor has an x value of 0.56.
47, and the y value was 0.4345, which was orange. Furthermore, a phosphor in which Me is Ca and Mg was manufactured and its characteristics were measured. This phosphor is composed of 45.0 g of CaF ₂ and 5.0 g of MgF ₂ , 0.10 g of Eu ₂ O ₃ and Mn _2.
0.10 g of O ₃ and 5.0 g of NH ₄ F were weighed, and these raw materials were treated in the same manner as in Example 1. This phosphor had an x value of 0.204 and ay value of 0.251, and had a color tone equivalent to that of the light blue phosphor currently widely used. Also, the emission brightness has a Y value of 61.1% and a Z value of 9.
It was 5% and the afterglow was also 220 msec. For Me, instead of Ca and Mg, Sr, Ba, Zn, C
d can be used alone or as a mixture of plural kinds.

【The invention's effect】

The phosphor of the present invention comprises MeF ₂ as a matrix, which is activated by both Mn and Eu, and the activation amount of Mn and Eu is changed within the range specified in the claims. The feature is that the color tone can be changed while maintaining sufficient afterglow. Furthermore, although the emission brightness changes with the emission color, even in the blue emission of x value = 0.15 and y value = 0.15, P-
The relative emission brightness of 50% or more of 22 phosphors is realized, and if the y value is 0.20, 70% or more of P-22 phosphors, and if the y value is 0.25, P-22 phosphors. A fluorescent body comparable to can be realized.

[Brief description of drawings]

FIG. 1 is an actual measurement graph showing emission intensity with respect to wavelength of a fluorescent substance according to an embodiment of the present invention, and FIGS. 2 and 3 are obtained by changing a and b shown in the general formula of claims. FIG. 4 is an actual measurement graph showing changes in x and y in CIE chromaticity display at this time, and FIG. 4 is an actual measurement graph showing afterglow characteristics.

Front page continuation (72) Inventor Minoru Kashiwagi 491, Oka, Nakanaka-cho, Anan-shi, Tokushima 100 Nichia Kagaku Kogyo Co., Ltd. Kogyo Co., Ltd. (56) Reference JP-A-57-103240 (JP, A) JP-A-51-64888 (JP, A) JP-A-50-151785 (JP, A)

Claims (2)

[Claims] Is represented by 1. A general formula _{(Me 1-ab Mn a Eu} b) F 2, Me is Mg, Ca, Sr, Ba, Zn and Cd
A long afterglow phosphor for display, wherein at least one of a and b is within the following range. 1 × 10 ⁻⁵ ≦ a ≦ 1 × 10 ⁻¹ 0 <b ≦ 1 × 10 ⁻¹ 2. A display according to claim 1, wherein a is 1 × 10 ⁻⁴ ≦ a ≦ 1 × 10 ⁻² b is 0.5 × 10 ⁻³ ≦ b ≦ 1 × 10 ⁻² . Long afterglow phosphor.