JPH0551577A - Pigmented blue-emitting fluophor - Google Patents

Abstract

PURPOSE:To provide the title fluophor which is excellent in fastness, chemical stability, and reflection spectrum characteristics and gives a good blue luminescence when applied to a cathode ray tube. CONSTITUTION:The title fluophor is prepd. by deposition a GeO2. Li2O. CoO. ZnO.NiO-based blue pigment on the surface of a blue-emitting fluophor.

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 required to have high transmittance in the emission wavelength region of the phosphor and 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 the blue light emitting phosphor, its emission peak is 450 nm.
A pigment that absorbs as little as possible in the vicinity and absorbs as much as possible in other wavelength regions may be used.

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, generally used cobalt aluminate is not effective for the purpose of improving the contrast because its body color does not match the emission spectrum of the blue phosphor, and in particular, its reflectance near 490 nm 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. Has the drawback of fading.

[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]

The present invention SUMMARY OF], in pigment-attached blue-emitting phosphor obtained by attaching a blue pigment on the surface of the blue-emitting _{phosphor, GeO 2 · Li 2 O ·} Co as a blue pigment
A pigmented blue light-emitting phosphor characterized by using an O.ZnO.NiO pigment.

Here, GeO ₂ Li ₂ O CoO Z
Examples of the nO / NiO pigment include Ge, Li, Co and Zn.
And a material containing Ni, usually obtained by firing at a temperature of 1000 ° C. or higher for several tens of minutes to several tens of hours, cooling and pulverizing, and a mixture of respective oxides or a complex oxide or solid solution thereof. Etc. are included. Note that uGeO ₂ · vLi ₂ O · wCoO · xZnO · y
The composition ratio of the NiO pigment is 0.2 ≦ v / u ≦ 0.5,
0.02 ≦ w / u ≦ 0.5, 0 ≦ x / u ≦ 0.5, 0 ≦
y / u ≦ 0.5 (particularly 0.3 ≦ v / u ≦ 0.
4, 0.03 ≦ w / u ≦ 0.4, 0 ≦ x / u ≦ 0.3,
It is preferably in the range of 0 ≦ y / u ≦ 0.3). 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, Si, Na, K, Ca, Mg, Ba, Fe, C
You may contain u, Mn, Ti, V, Al, Sn, Sb, Cr, Pr, etc. 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 0.3 to 30.
A weight% range is preferred. 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]

As a result of various investigations by the present inventors on pigments having a body color matching the emission spectrum of the blue-emitting phosphor, the above-mentioned GeO ₂ · Li ₂ O-CoO-ZnO-NiO-based pigment meets the above-mentioned conditions. Found to meet.

FIG. 1 shows uGeO ₂ .vLi ₂ O.wCo.
O.xZnO.yNiO pigment (u = 1.0, v = 0.3
3, w = 0.067, x = 0.27, y = 0) and a diffuse reflection spectrum of a cobalt aluminate pigment, and FIG. 2 is a graph showing ZnS: Ag which is a typical blue light emitting phosphor. 3 is a graph showing an emission spectrum of Cl phosphor. As is clear from comparing FIG. 1 and FIG. 2, the emission spectrum of the phosphor and the diffuse reflectance of the pigment, that is, the body color, are higher than those of the cobalt aluminate pigment by uGeO ₂ · vLi.
It can be seen that the ₂ O.wCoO.xZnO.yNiO pigments are more consistent. In addition, in comparison with the above cobalt aluminate pigment, uGeO ₂ · vLi ₂ O · wCoO · x
It can be seen that the ZnO / yNiO pigment has a low reflectance at 480 to 540 nm, which greatly affects the improvement of contrast, and has an excellent filter effect.

[0013]

EXAMPLE To 100 parts of silver-activated zinc sulfide blue light-emitting phosphor, 100 parts of distilled water was added to make a slurry, and uGeO ₂ was added.
_{· VLi 2 O · wCoO · xZnO} · yNiO pigment (u
= 1.0, v = 0.33, w = 0.067, x = 0.2
7, y = 0) 7 parts were added and the mixture was heated to 45 ° C., while 0.36 parts of gelatin as a binder and 0.
After adding 3 parts of an aqueous solution and adjusting the pH to 4.1 with acetic acid and allowing to cool to room temperature, 7.5 parts of a 50% glutaraldehyde aqueous solution was added to cure the binder. Further, for comparison, 3 parts of cobalt aluminate was attached in the same manner as in the above-mentioned example instead of the above-mentioned pigment 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. As is clear from FIG. 3, compared with the phosphor of the comparative example, the phosphor of the example has 480 to 540 n
It can be seen that the reflectance at m is low and is closer to the emission spectrum of the phosphor.

[0014]

According to the present invention, by adopting the above constitution, a blue pigment having a diffuse reflectance matching the emission spectrum of the blue light emitting phosphor can be attached.
It has become possible to provide an excellent blue light-emitting phosphor that does not deteriorate in the step of attaching it to the phosphor.

[Brief description of drawings]

[Figure 1] Cobalt aluminate pigment and GeO ₂ · Li ₂ O
It is a graph showing a diffuse reflectance spectrum of a CoO / ZnO / NiO-based 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 GeO ₂ · Li
₃ is a graph showing a diffuse reflectance distribution of a blue light emitting phosphor to which a ₂ O / CoO / ZnO / NiO pigment is attached.

Claims (3)

[Claims] 1. A pigmented blue light-emitting phosphor obtained by adhering a blue pigment to the surface of a blue light-emitting phosphor, characterized in that a GeO ₂ · Li ₂ O · CoO · ZnO · NiO pigment is used as the blue pigment. A blue light emitting phosphor with a pigment. 2. The method of claim 1] _{· GeO 2 · Li 2 O ·} CoO ZnO ·
NiO pigments with Si, Na, K, Ca, Ba, Fe, M
g, Cu, Mn, V, Ti, Sb, Cr, Pr, Sn,
The blue light-emitting phosphor with a pigment according to claim 1, wherein a blue pigment containing Al or the like is used. 3. uGeO ₂ .vLi ₂ O.wCoO.x
The composition ratio of ZnO / yNiO-based pigment is 0.2 ≦ v / u ≦
0.5, 0.02 ≦ w / u ≦ 0.5, 0 ≦ x / u ≦ 0.
3. The blue light-emitting phosphor with pigment according to claim 1, wherein the range is 5, 0 ≦ y / u ≦ 0.5.