JP2598586B2 - Green light emitting phosphor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a green light emitting phosphor,
In particular, the present invention relates to a green light-emitting phosphor having high color purity and excellent luminance saturation characteristics under high current density.

[0002]

2. Description of the Related Art In general, a ZnS-based phosphor is used as a green light-emitting phosphor for a color cathode ray tube, and typical examples thereof include ZnS: Cu, Au, Al phosphor and ZnS: C.
u, Al phosphor and the like.

In recent years, as the size of a color cathode ray tube increases, it is necessary to increase the luminance of the fluorescent film. However, in order to increase the luminance of the fluorescent film, stimulation with a higher current density is required. However, green light emitting phosphors such as ZnS: Cu, Au, Al phosphor and ZnS: Cu, Al phosphor, which are conventionally used, have poor current-luminance saturation characteristics, and the luminance saturation phenomenon occurs under high current density. There is a problem that appears.

[0004] Recently, researches for developing a rare-earth green light-emitting phosphor having excellent current-luminance saturation characteristics under high current density conditions, such as a projection tube, have been actively conducted.

For example, Japanese Patent Application Laid-Open No. 62-253686 discloses a terbium-activated oxychloride lanthanum phosphor (LaOCl: Tb) as an excellent phosphor having excellent current-luminance saturation characteristics. Aluminum gallate phosphor (Y ₃ (Al, Ga)
₅ O ₁₂ : Tb) and terbium-activated yttrium aluminate phosphor (Y ₃ Al ₅ O ₁₂ : Tb) have also attracted attention.

[0006]

However, such a rare earth phosphor is unstable to moisture and has a problem that its initial luminous efficiency is low when it is used for a screen film.

It is an object of the present invention to provide a green light emitting phosphor which has excellent luminance saturation characteristics and excellent color tone even at a high current density by maximizing the advantages of a rare earth phosphor while minimizing the above-mentioned problems. Is to do.

[0008]

In order to achieve the above-mentioned object, a green light-emitting phosphor according to claim 1 comprises ZnS: C
Mixing of u, Au, Al phosphor and Tb-activated rare earth phosphor
And the Tb-activated rare earth phosphor is Y ₃ (Al,
Ga) ₅ O ₁₂ : Tb phosphor or LaOCl: Tb fluorescence
It is characterized by being at least one of the body. Claim
The green light-emitting phosphor according to claim 2 is a green light-emitting phosphor according to claim 1.
A photophosphor, wherein the ZnS: Cu, Au, Al fluorescence
The mixing ratio of the Tb-activated rare earth phosphor to the phosphor is 95: 5.
The ratio is 80:20. Claim 3
The green light-emitting phosphor according to claim 2,
Wherein the ZnS: Cu, Au, Al phosphor and the
The mixing ratio with the Tb-activated rare earth phosphor is 95: 5 to 8
5:15.

[0009]

The phosphor according to the present invention comprises ZnS: Cu, Au,
A mixed phosphor obtained by mixing Y ₃ (Al, Ga) ₅ O ₁₂ : Tb phosphor or LaOCl: Tb phosphor with Al phosphor,
When the ZnS: Cu, Au, Al phosphor is used alone in the color cathode ray tube, the emission luminance is significantly increased.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for manufacturing a green light emitting phosphor according to the present invention will be described.

First, ZnS: Cu, Au, Al phosphor,
Y ₃ (Al, Ga) ₅ O ₁₂ : Tb and LaOCl: Tb
Manufacture phosphor.

[0012] (1) ZnS: Cu, Au ,硫銅the manufacture ZnS100g of Al phosphor _{(CuSO 4 · 5H 2 O)} 0.0
55 g (Cu content is 140 ppm based on ZnS), chloroauric acid (HAuCl _4.
4H ₂ O) 0.021 g (the amount of Au is 1
00ppm), aluminum nitrate (Al (NO _{3) 3} 9
The amount of Al relative to H ₂ O) 0.28g (ZnS 200
ppm), dissolved in pure water, and 0.11 g of ammonium iodide (NH ₄ I) and 0.03 g of potassium iodide (KI) were further added as fluxes and mixed until uniform. A wet mixture is obtained. The obtained wet mixture is dried at 120 ° C. for 12 hours. The dried mixture is filled in a heat-resistant quartz crucible and fired at a temperature of 960 ° C. for 2 hours in a reducing atmosphere of hydrogen sulfide. After firing, a ZnS: Cu, Au, Al green light emitting phosphor is obtained through cooling, washing and drying steps.

[0013] _{(2) Y 3 (Al,} Ga) 5 O 12: Tb phosphor manufactured yttrium oxide (Y ₂ O ₃₎ 100g aluminum oxide (Al ₂ O ₃₎ 52.7g, gallium oxide (Ga ₂
O ₃ ) 41.51 g and terbium oxide (Tb)
After adding 10 g of ₄ O ₇ ) and ₇ g of BaF ₂ as a flux, mix using a ball mill until uniform. The mixture is filled in a heat-resistant quartz crucible and fired at 1500 ° C. for 2 hours. After firing cooling, Y ₃ via the rinsing and drying steps
(Al, Ga) ₅ O ₁₂ : Tb phosphor (hereinafter referred to as P53 (G
a). Get)

(3) Production of LaOCl: Tb phosphor 100 g of lanthanum oxide (La ₂ O ₃ ) and 4.68 g of terbium oxide (Tb ₄ O ₇ ) and ammonium chloride (NH ₄₎
After adding 63 g of Cl), mix uniformly using a ball mill. Place the mixture in a heat-resistant quartz crucible, 400 ° C
, And then second firing at 1100 ° C. for a second time. Wash with water and dry to obtain LaOCl: Tb phosphor.

After preparing the phosphor as described above, Zn
S: The Cu, Au, Al phosphor and P53 (Ga) are mixed and crushed uniformly by a ball mill. The LaOCl: Tb phosphor is mixed with the ZnS: Cu, Au, Al phosphor in the same manner.

Hereinafter, preferred embodiments of the present invention will be described.

Example 1 A green phosphor of the present invention is obtained by adding 5% by weight of P53 (Ga) to 95% by weight of a ZnS: Cu, Au, Al phosphor and then uniformly mixing the resulting mixture with a ball mill. A fluorescent film of a color cathode ray tube employing this was formed by an ordinary method. The luminance of the obtained fluorescent film was measured, and the result is shown in Table 1.

[Embodiment 2] The same procedure as in Embodiment 1 was carried out except that 90% by weight of ZnS: Cu, Au, Al phosphor was used.
53 (Ga) was 10% by weight. The luminance of the obtained fluorescent film was measured, and the result is shown in Table 1.

[Embodiment 3] The same procedure as in Embodiment 1 was carried out, except that ZnS: Cu, Au, and Al phosphors were 85% by weight and P
53 (Ga) was set to 15% by weight, and the results are shown in Table 1.

Example 4 The same procedure as in Example 1 was carried out, except that ZnS: Cu, Au, and Al phosphors were 80% by weight and P
53 (Ga) was set to 20% by weight, and the results are shown in Table 1.

Example 5 A phosphor film for a cathode ray tube was formed by introducing 95 wt% of ZnS: Cu, Au, Al phosphor and 5 wt% of LaOCl: Tb phosphor. The manufacturing process was the same as in Example 1. Table 1 shows the luminance of the obtained fluorescent film.
It was shown to.

[Embodiment 6] The same procedure as in Embodiment 5 was carried out, except that ZnS: Cu, Au, Al phosphor was 90% by weight and L
The content of the aOCl: Tb phosphor was set to 10% by weight, and the results are shown in Table 1.

[Embodiment 7] The same procedure as in Embodiment 5 was carried out except that the ZnS: Cu, Au, Al phosphor was 85% by weight and L
aOCl: Tb phosphor was 15% by weight.
It was shown to.

Example 8 The same procedure as in Example 5 was carried out, except that the ZnS: Cu, Au, Al phosphor was 80% by weight and L
The content of the aOCl: Tb phosphor was set to 20% by weight, and the results are shown in Table 1.

[0025]

[Table 1]

Table 1 shows the relative luminance relationship depending on the phosphor mixture ratio and various current densities. As can be seen from Table 1, P53
As the mixing ratio of the (Ga) or LaOCl: Tb phosphor increases, the emission luminance at a low current density gradually decreases, but the emission luminance increases at a high current density.

That is, as the mixing ratio of the rare-earth phosphor increases, the initial emission luminance decreases at a low current density.
Under a high current density, it means that the luminance saturation characteristics have been improved. And if the rare earth phosphor is mixed in excess,
This is impractical because the initial luminance is even lower.

Therefore, ZnS: Cu, Au,
The mixing ratio of the Al phosphor to the rare earth phosphor is 95: 5 to 80:20, preferably 95: 5 to 85: 1.
5

FIG. 1 is a graph showing the relative luminance according to a change in current density when a conventional green light emitting phosphor and the green light emitting phosphor of the present invention are applied to a color cathode ray tube.
S: Cu, Au, Al phosphor, b: Zn of Example 6
S: Cu. Au, Al phosphor (90% by weight) and LaOC
l: A mixed phosphor with a Tb phosphor (10% by weight), c: ZnS: Cu, Au, Al phosphor (90% by weight) of Example 2 and Y ₃ (Al, Ga) ₅ O ₁₂ : Tb A mixed phosphor with a phosphor (10% by weight) is shown.

As can be seen from FIG. 1, the current density is 0.7
At μA / cm ² or less, the emission luminance of the mixed phosphor according to the present invention is lower than when the ZnS: Cu, Au, Al phosphor is used alone, but above that, it is increased by about 10 to 15%.

[0031]

As described above, the green light-emitting phosphor according to the present invention comprises ZnS: Cu. Au. Y for Al phosphor
₃ (Al, Ga) ₅ O ₁₂ : Tb phosphor or laOC
1: A mixed phosphor obtained by mixing a Tb phosphor, and ZnS: C
Luminance is significantly increased when u, Au, and Al phosphors are used alone in a color cathode ray tube.

The mixed phosphor of the present invention was excellent in luminance saturation characteristics and color tone under high current density.

The present invention is particularly applicable to a phosphor adapted to a large-sized color cathode ray tube, and is expected to have an extremely large industrial value.

[Brief description of the drawings]

FIG. 1 is a graph showing a relative luminance change due to a change in current density when a conventional green light emitting phosphor and the green light emitting phosphor of the present invention are applied to a color cathode ray tube.

Claims (3)

(57) [Claims] 1. ZnS: Cu, Au, Al phosphor and Tb
A Tb-activated rare earth phosphor comprising a mixture of activated rare earth phosphors;
If the phosphor is Y ₃ (Al, Ga) ₅ O ₁₂ : Tb phosphor or
Is at least one of LaOCl: Tb phosphors
A green light-emitting phosphor , characterized in that: 2. The phosphor according to claim 1, wherein said ZnS: Cu, Au, Al phosphor is used.
The mixing ratio with the Tb-activated rare earth phosphor is 95: 5 to
2. The green color of claim 1, wherein the ratio is 80:20.
Luminescent phosphor. 3. The ZnS: Cu, Au, Al phosphor and
The mixing ratio with the Tb-activated rare earth phosphor is 95: 5 to
The green color according to claim 2, wherein the ratio is 85:15.
Luminescent phosphor.