JPH0551579A - Pigmented blue-emitting fluophor - Google Patents

Abstract

(57) [Abstract] [Purpose] An object of the present invention is to provide a pigmented blue light-emitting phosphor which is excellent in robustness, chemical stability, and reflection spectrum characteristics, and which can obtain good blue light emission when applied to a cathode ray tube. . [Constitution] In a pigmented blue light-emitting phosphor obtained by adhering a blue pigment to the surface of a blue light-emitting phosphor, C is used as a blue pigment.
It is a blue light-emitting phosphor with a pigment characterized by using an oO.ZnO.Al ₂ O ₃ pigment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pigmented blue light emitting phosphor suitable for a phosphor film such as a color cathode ray tube.

[0002]

2. Description of the Related Art It is known to attach a filter material, which absorbs reflection of external light on a phosphor screen, to the surface of a phosphor in order to improve the contrast of an image of a color cathode ray tube or a fluorescent display tube. In addition, the filter material may be used to sharpen the emission spectrum of the phosphor. This filter material is generally required to have a high transmittance in the emission wavelength region of the phosphor and a low transmittance in other wavelength regions. Due to this characteristic of transmittance, it is possible to absorb a light component that does not match the light emission of the phosphor itself and improve the contrast under bright outside light. That is,
In a blue light emitting phosphor, its emission peak is 45
It is conceivable to use a pigment that absorbs as little as possible near 0 nm and absorbs as much as possible in other wavelength regions.

As a blue pigment of this type, JP-A-54-2
Ultramarine (3NaAl ・ SiO ₂・ Na ₂
S ₂ ), dark blue (Fe ₄ Fe (CN) _{6 3}・ nH
₂ O), cobalt aluminate (CoO ・ nAl ₂ O ₃ ).
, Cerulean blue (CoO.nSnO ₂ ), copper sulfide (CuS), etc. have been proposed. However, the cobalt aluminate which is generally used does not have a body color partially matching the emission spectrum of the blue phosphor.
It has been found that a problem arises when the aim is to improve the contrast because the reflectance near m is high.

Although some of the ultramarine blues that are practically used have excellent characteristics as compared with cobalt aluminate, they are extremely poor in chemical stability, so that they are attached to a phosphor or applied to a cathode ray tube. The color fades in and does not show a better effect than cobalt aluminate.

[0005]

SUMMARY OF THE INVENTION Therefore, the present invention solves the above-mentioned drawbacks, is excellent in fastness, chemical stability and reflection spectrum characteristics, and provides a good blue emission when applied to a cathode ray tube. It is intended to provide an attached blue light emitting phosphor.

[0006]

Means for Solving the Problems In the pigmented blue light-emitting phosphor obtained by adhering a blue pigment to the surface of the blue light-emitting phosphor, the inventors of the present invention used CoO.ZnO.Al as the blue pigment.
_The present invention has been accomplished by finding that the above problems can be solved by using a ₂ O ₃ pigment.

Here, the CoO.ZnO.Al ₂ O ₃ pigment is, for example, a raw material containing Co, Zn and Al, which is usually fired at a temperature of 1000 ° C. or higher for several tens of minutes to several tens of hours,
It is obtained by cooling and then pulverizing, and includes a mixture of respective oxides, a complex oxide thereof, a solid solution, or the like. Note that xCoO / yZnO
The composition ratio of zAl ₂ O ₃ pigment is 0.2 ≦ x / z ≦
0.7, 0.2 ≦ y / z ≦ 0.7 range (particularly 0.3
≦ x / z ≦ 0.6, 0.3 ≦ y / z ≦ 0.6). The blue pigment in this range is suitable for combination with the blue-emitting phosphor because it has little change in color tone.

If necessary, various fluxes and other elements may be added during the firing of the above pigment. Specifically, Li, Na, Ca, Mg, Ba, Fe, Ni,
Cu, Mn, Ti, V, Si, Sn, Sb, Cr, Pr
Etc. may be contained. These elements can be added in the range of about 5% by weight or less. By adding the above elements in this range, a more preferable color tone can be obtained as a blue pigment.

The blue light-emitting phosphor that can be used in the present invention has a main part of the emission spectrum within the range of 380 to 500 nm, and specifically, it is a silver-activated zinc sulfide-based phosphor [ZnS: Ag, X (X is halogen or A
l), ZnS: Ag, M, X (M is Ga, In, etc., X is halogen or Al)], Y ₂ SiO ₅ : Ce, Ca ₂ B
₅ O ₉ Cl: Eu, (Ba _x Mg _1-x ) O.nAl ₂ O
₃ : Eu (0 ≦ x ≦ 1, 7 ≦ n ≦ 8), SrSi ₃ O _{8
Cl 4: Eu, CaWO 4,} CaWO 4: Pb, BaF
Examples include Cl: Eu, Gd ₂ O ₂ S: Tb, ZnS: Zn, and the like.

The amount of the above blue pigment attached is 0.1 to 30.
The range of weight% is preferable, and 0.3 to 15 weight% is more preferable. If the adhesion amount is less than the lower limit value, the filter effect is too small, and if it exceeds the upper limit value, the emission brightness becomes insufficient.

[0011]

The present inventors have conducted various studies on phosphors and pigments in order to obtain a pigmented blue light-emitting phosphor having excellent fastness, chemical stability and reflection spectrum characteristics and exhibiting good color purity. It was found that the blue light-emitting phosphor to which the CoO.ZnO.Al ₂ O ₃ based pigment (1) adheres satisfies the above conditions. That is, this phosphor exhibited sufficient chemical stability under the conditions of the phosphor film forming process, and exhibited good reflection characteristics and good blue emission.

FIG. 1 shows xCoO.yZnO.zAl ₂ O.
FIG. 2 is a graph comparing the diffuse reflection spectra of _three pigments (x = 0.37, y = 0.46, z = 1.0) and cobalt aluminate pigments, and FIG. 2 shows a typical blue light emitting phosphor. 6 is a graph showing an emission spectrum of a ZnS: Ag, Cl phosphor. As is clear from FIGS. 1 and 2,
XCoO / yZnO / zA from cobalt aluminate pigment
It can be seen that the diffuse reflectance, that is, the body color of the l ₂ O ₃ pigment is closer to the emission spectrum of the blue-emitting phosphor. In addition, compared to cobalt aluminate pigment, xCoO ・ yZnO ・ z
The Al ₂ O ₃ pigment has a low reflectance at 480 to 600 nm, which greatly affects the improvement of contrast, and has an excellent filter effect. The pigmented blue light-emitting phosphor of the present invention has excellent color purity, and when applied to a fluorescent film of a color television or the like, an image with a wider color reproducibility region can be obtained.

[0013]

Example To 100 parts of silver activated zinc sulfide blue light emitting phosphor, 100 parts of distilled water was added to form a slurry, and xCoO.
yZnO.zAl ₂ O ₃ pigment (x = 0.37, y = 0.
46, z = 1.0) 7 parts and heating to 45 ° C., while adding 0.36 parts of gelatin and 0.3 parts of gum arabic as an aqueous solution as a binder, and adding acetic acid to a pH of 4.1. After cooling to room temperature after adjusting to 50,
% Glutaraldehyde aqueous solution was added to cure the binder. For comparison, instead of the above pigment, 3 parts of cobalt aluminate was attached in the same manner as in the above example to obtain a pigmented phosphor of the comparative example. FIG. 3 is a graph comparing the diffuse reflectance distributions of the pigmented phosphors of the above Examples and Comparative Examples, and the pigmented blue light emitting phosphor of the Example is compared with the pigmented blue light emitting phosphor of the Comparative Example. 480-6
It can be seen that the reflectance at 00 nm is low and is closer to the emission spectrum of the phosphor.

[0014]

EFFECTS OF THE INVENTION The present invention can provide a pigmented blue light-emitting phosphor having good reflection characteristics and light emission characteristics by adopting the above-mentioned constitution, and the blue pigment according to the present invention can emit fluorescent light. Since it does not deteriorate in the process of attaching to the body,
It has become possible to provide a chemically stable pigmented blue-emitting phosphor.

[Brief description of drawings]

[Figure 1] Cobalt aluminate pigment and CoO / ZnO / A
It is a graph showing the diffuse reflectance spectrum of the l ₂ O ₃ pigment.

FIG. 2 ZnS: Ag, which is a typical blue light-emitting phosphor,
7 is a graph showing an emission spectrum of a Cl phosphor.

FIG. 3 Cobalt aluminate pigment and CoO.ZnO
- is a graph showing the diffuse reflectance spectrum of the blue-emitting phosphor and the Al ₂ O ₃ pigments adhered.

Claims (3)

[Claims] 1. A pigmented blue light-emitting phosphor having a blue pigment attached to the surface of a blue light-emitting phosphor, wherein a CoO.ZnO.Al ₂ O ₃ pigment is used as the blue pigment. Blue light emitting phosphor. Wherein CoO · ZnO · Al ₂ O ₃ pigment in L
i, Na, Ca, Mg, Ba, Fe, Ni, Cu, M
The blue light-emitting phosphor with a pigment according to claim 1, wherein a blue pigment containing n, Ti, V, Si, Sn, Sb, Cr, Pr or the like is used. _3. The composition ratio of xCoO.yZnO.zAl ₂ O ₃ based pigment is 0.2 ≦ x / z ≦ 0.7, 0.2 ≦ y / z.
3. The method according to claim 1, wherein the range is ≤0.7.
A blue light emitting phosphor with a pigment as described above.