JPS6281482A - Pigment-bonded green fluorescent phosphor - Google Patents

Abstract

PURPOSE:To provide the titled phosphor capable of improving the contrast of a picture on a cathode ray tube for color television and which comprises a green fluorescent phosphor and a particular green pigment particle bonded on the surface thereof. CONSTITUTION:Particles of a (CoO)n.Al2O3-based green pigment (wherein n is 1.0<=n<=2) having an average particle diameter of 0.001-0.1mum and having a reflectance in the range as enclosed by curves a and b in the drawing when the reflectance of BaSO4 powder is assumed to be 100% is bonded onto the surface of a green fluorescent phosphor [e.g., copper-activated, chlorine- coactivated zinc sulfide phosphor (ZnS:Cu,Cl)] in an amt. of 0.01-3wt% based on the phosphor.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Industrial Field of Application The present invention relates to a green light-emitting phosphor having pigment particles attached to its surface (hereinafter referred to as a pigmented green light-emitting phosphor), and in particular to a green light-emitting phosphor for television use. This invention relates to a pigmented green-emitting phosphor for use in contrast cathode ray tubes.

B. Prior art When green pigment particles, blue pigment particles, and red pigment particles are attached to the particle surfaces of a green-emitting phosphor, a blue-emitting phosphor, and a red-emitting phosphor, respectively, of a cathode ray tube for television, their The color filter effect of the pigment particles cuts out a part of the undesirable visible range of the emission spectrum, increasing the color purity of the emitted color.Furthermore, the absorption effect of external light by the pigment particles reduces reflection. It is known that as a result, the contrast of the image dramatically increases by -1-5 (Japanese Patent Application Laid-Open No. 50-1989 Fi6146).

Conventionally, blue pigments such as ultramarine or cobalt blue have been used for blue-emitting phosphors, red pigments such as cadmium selenide, red lead, and hemkara have been used for red-emitting phosphors, and oxidized pigments have been used for green-emitting phosphors. Ri [1), (Cr203) and T
f (12Z n OCOn N !O Faceful Japanese Unexamined Patent Publication No. 1361139/1983), etc. are known.

C1 Problems to be Solved by the Invention The conventional green pigment that is attached to the surface of the green light-emitting phosphor that has been used in high-contrast cathode ray tubes for televisions has a large particle size. A green pigment with a large particle size does not have a sufficient color filtering effect depending on the amount of adhered pigment, and in order to expect the same color filtering effect, a large amount of Br4 II must be used.

The average particle size of the conventional green wish 4 particles is 0.1~0.5μm
The amount of the phosphor is about 4 to lnlIIn. In this case, it cannot be said that the 4 particles are sufficiently small compared to the phosphor particles t, and the long-awaited filter effect cannot be achieved unless a considerably large number of pigments are used.

On the other hand, if the pigment particles are large, they may easily peel off from the phosphor. Peeling from the phosphor surface is an important problem for pigmented green-emitting phosphors. This is because peeling of pigments not only reduces the ability of a color television cathode ray tube screen to reproduce the desired contrast or tone, but also causes color mixing on other color dots or stripes.
This has the disadvantage of easily causing so-called "fogging". In order to prevent delamination, more adhesive is required, which often deteriorates the application properties to cathode ray tube faceplates.

Means for Solving Problem D1 The present inventors conducted numerous experiments on cobalt blue, which has been conventionally used as blue filter particles on the surface of blue-emitting phosphors, and found that (C.

O〉.・By using a special cobalt blue represented by Al2O3 with an n value of 1 or more and further limiting its average particle size within a specific range, we have created a phosphor that surpasses conventional green pigments. A green pigment was realized.

It is known that the color of (CoO) n-A I 203 pigments changes depending on the value of n. When the value of n is small, 0.5 or less, a bright blue color is produced, and from 0.5 to 1.0, a deeper blue color is produced, and it is used as a blue pigment for cobalt blue. However, n is 1.0 or more"-
In this case, the green color becomes brighter and the brightness becomes lower, making the entire image dark green.

Cobalt blue with an n value of 1 or more is Tj (12-Z n
O-Co O-N i OfAKYF has extremely low reflectance and is difficult to imagine as a preferable green pigment.

In particular, Tiα2-Z n O-(': o O-N i
Whereas the O pigment shows a dull reflectance in the green range of 500-555-0n, n = 1.52 (Cod)
. -Al2O3 does not have a very high reflectance in this range. For this reason, cobalt blue with a high n value has an overall dark green color and does not exhibit desirable characteristics as a green pigment. However, the present inventors have developed a phosphor with a contrast superior to that of conventional phosphors by making fine particles of cobalt blue, which is unique and has a high n-value and does not exhibit superior characteristics, and attaching it to the surface of the phosphor. succeeded in realizing it. Therefore, the green pigment used in the present invention is ((
”:oo).・The value of n expressed by Al2O3 is 1.0~
2.6, preferably a dark green pigment with n of 1.2 to 2.0.

A further characteristic feature is that (C) used in the present invention.

O).・Al2O3-based green pigment has an average particle diameter of 0°0
It is adjusted within the range of 0.01 to 0.1 μm, which is extremely fine compared to conventional green pigments.

On the other hand, the green-emitting phosphor used in the pigmented phosphor of the present invention includes all phosphors that emit green light, such as copper-activated chlorine co-activated zinc sulfide phosphor (ZnS:Cu, CI),
Copper-activated aluminum co-activated zinc sulfide phosphor (ZnS:C
u, AI), copper and fully activated aluminum coactivated zinc sulfide phosphor (ZnS:Cu, Au, AI), fully activated aluminum coactivated zinc sulfide phosphor (ZnS:Au, AI),
Copper activation chlorine co-activation sulfide leaf lead power tomiuno, phosphor (Z n
+Cd)S: Ctl, CI), copper-activated aluminum coactivated zinc cadmium sulfide phosphor (Zn, (:d)S
:CLl, Al), self-activated zinc oxide phosphor (7 units 0:
Zn), Mango 21-dimensional zinc silicate phosphor (2n2s
ioa:Mn), mankan-activated arsenic-coactivated zinc silicate phosphor (Zn2S i Oa:Mn, As), etc.
It can be used for all of these.

It adheres to the surface of the phosphor of the present invention and exhibits particularly excellent properties (
The preferred reflectance of CoO) n-A I 203 is in the region surrounded by curves a and 1) in FIG. However, the first
The measurements shown in the figure were performed with the reflectance of barium sulfate powder as 100%. To measure the reflectance, barium sulfate powder or (CnO), Al 203 powder is pressed to a sufficient thickness with a surface pressure of 10 kg/cm2 using a glass plate with a smooth surface. The reflectance was measured using an integrating sphere. At the time of measurement, the light was illuminated in a direction substantially perpendicular to the light plane, and the light that was diffusely reflected in all directions except the direction of the 9.1 light was collected and received. The illumination light does not include any light rays with an inclination of 5 degrees or more with respect to the center line of the illumination light beam, and the inclination of the center line of the illumination light beam is 10 degrees with respect to the normal to the sample surface. Measured as within.

(Coo) on the surface of the green-emitting phosphor mentioned above.・Al2O3
As a method for producing a pigmented green light-emitting phosphor by attaching green pigment particles, any of the following methods may be used: a method using an inorganic adhesive, a method using a combination of inorganic and organic adhesives, and a method using an organic adhesive.

E1 action and effect FIG. 2 shows (Co 2 O) used in the pigmented green light-emitting phosphor of the present invention.・Al2O3-based green pigment (curve a),
As a conventional green pigment, it is said to have a relatively high contrast effect (Ti02-ZnO-Coo-N1o)
The spectral reflectance curve of a green pigment (curve b) is shown.

From this figure, it can be seen that the conventional green pigment shown by the curve has a high reflectance in the wavelength range of 500 nm to 550 nm, which corresponds to green light emission, and a low reflectance in the wavelength range below 500 nm or above 5510 nm. , high contrast for color television! - It is expected that the green pigment applied to the surface of the green light-emitting phosphor used in cathode ray tubes will have excellent effects as a filter material*.1. On the other hand, as shown by curve a, the green pigment used in the phosphor of the present invention has an overall lower reflectance than the curve a.
The body color is dark green, which appears to be inappropriate as a border color.

However, through experiments, the present inventor found that (
COO). Compared to conventional green pigments, the Al+03-based green pigment has a very small average particle size (1,1101~0.1 μm), which increases the hiding power of the phosphor surface and also increases the reflectance. It was discovered that excellent contrast effects can be obtained with a small amount of adhesion due to the low amount of adhesion.

FIG. 3 shows a green pigment with n=1.52, i.e. (Co
O) 1.62.Al2O3 green pigment and a pigment (TiO2-ZnO-C60-Nir))-based green pigment were separately attached to the surface of ZnS:Cu, AI green-emitting fluorescent lO-. It shows the specific reflectance with respect to the amount of adhesion.

Here, the specific reflectance was measured by the following method. The sample is irradiated with a light source with an energy distribution of 3124 nm, and the tristimulus value (CTE color representation method) of the reflected light is measured. Calculate the amount of each pigment attached.

This side (Co(1)+52・Al2O3 system green face half 4 (curve a) is the conventional T i 02 Zn0-Co
.

- Only 1/3 compared to NiO-based green pigment (curve b)
The same specific reflectance is shown with 1/4 the amount.

Thus, the green pigment used in the present invention (COO
).・Since the Al2 (13-based green eα pigment particles) can reduce the amount of adhesion compared to conventional green pigments, the amount of peeling decreases depending on the amount of adhesion, making it an excellent color television cathode ray tube screen. It maintains the ability to reproduce different color tones and suppresses color mixing onto other color dots or stripes.Not only that, it also reduces the amount of pigments and adhesives required. The coating properties are greatly improved, which is very advantageous for cathode ray tube manufacturing.

Next, (Coo)1.62・Al2O used in the present invention
3 series green face sheep-1, and conventional (T102-Zll(1)
-(:oO-NiO)-based green round phosphor, ZnS
: CIJ, Al Midorimura The contrast of the pigmented phosphor attached to the light-emitting phosphor was compared. The contrast was compared by measuring relative luminance and specific reflectance for various amounts of pigment attached.

The results are shown in FIG. In this case, the specific reflectance and relative luminance of the phosphor to which no pigment is attached are 100%.

From FIG. 4, curve a of the green-emitting phosphor of the present invention is shown.
) is in the practical range of specific reflectance of 60% to 100%,
It can be seen that the relative luminance is higher, that is, the contrast is higher than that of the conventional phosphor (curve 1).

In addition, during the cathode ray tube FJJ manufacturing process, 45 (1'(':
The heating process includes the addition of 4. Decrease in brightness is often a problem. Cause and []
For example, thermal stability of = 12- adhesion amount It can be mentioned.

The phosphor of the present invention, in which the (CoO)152.Al2O3 green pigment used in the present invention is attached to the ZnS:Cu, AI green light-emitting phosphor, showed a reduction in brightness of 1 as a result of a heating test at 450°C for 30 minutes. %, but TiO2ZnOCoo-
NiO green l! A conventional phosphor in which IIN was attached to a ZnS:Cu, AI green-emitting phosphor showed a reduction in brightness of as much as 8% in a similar heating test.

As described above, the phosphor of the present invention can improve contrast by adhering a small amount of pigment to the surface, and has a greater contrast effect than the conventional phosphor to which green pigment is attached. Furthermore, by reducing the amount of pigment deposited, the amount of adhesive can also be reduced, resulting in improved coating properties. Besides, (CoO).・A
12O3 pigments have high thermal stability, are less likely to cause a decrease in the brightness of the phosphor, and have obtained good results.

F. Preferred embodiment Examples of the present invention will be described below.

Example 1 Yume Potassium silicate (K2S i fla) o,
I heavy i1? J was dissolved in water to prepare a 0.05% water lff solution. In this 0.05% aqueous solution, an average particle size of 7 μm was added.
Copper-activated aluminum co-activated zinc sulfide green-emitting phosphor (
100 parts by weight of 2nS (Cu, AI) was added and the particles were sufficiently and uniformly dispersed using a stirrer until they became primary particles. In this way, a phosphor dispersion liquid was obtained.

On the other hand, potassium silicate n, ooni heavy acetate was dissolved in water to prepare a 0.001% aqueous solution. This 0.001% aqueous solution has (C00) with an average particle size of about (1,008 Bm).
1.62 - 0.1 part by weight of A I 20a green M size particles (manufactured by BASF) was added and sufficiently dispersed with a ball mill until uniform. In this way, a pigment particle dispersion was obtained. Next, the phosphor dispersion and the pigment particle dispersion were mixed with stirring, and aluminum nitrate [A I (NO3
) 3] 0. (105 parts by weight was gradually added. The pH of the mixture was then adjusted to 7. After standing, the supernatant liquid was removed by decantation, the precipitate was washed with water, and the water was sufficiently removed by filtration. After that, it was dried to obtain a pigmented green light-emitting phosphor of the present invention.

For comparison, (CO0)152 as green pigment particles
・Instead of Al2O3 green pigment particles (T102-Z
A conventional pigmented phosphor was manufactured in exactly the same manner as described above using nO-CoO-NiO)-based green pigment particles.

Example 2 0.1 part by weight of potassium silicate was dissolved in water to give a concentration of 0.05%.
An aqueous solution was prepared. To this 0.05% aqueous solution, parts by weight of a copper-activated aluminum co-activated zinc sulfide green light-emitting phosphor (ZnS:Cu, AI) with an average particle diameter of 771 m and 0.5 parts by weight of an acrylic emulsion were added. The mixture was sufficiently uniformly dispersed using a stirrer until it became primary particles. In this way, a phosphor dispersion liquid was obtained.

On the other hand, 0.0025 parts by weight of potassium silicate was dissolved in water to prepare a 0.0025% aqueous solution. This 0.0025
% aqueous solution with an average particle size of about 0.008/Zm.
) 0.5 parts by weight of 1.62AI20a green pigment particles were added and thoroughly dispersed until uniform. In this way, a face 11 particle dispersion was obtained.

Next, the phosphor dispersion and the pigment particle dispersion were mixed with stirring, and 0.05 parts by weight of aluminum nitrate was gradually added. Thereafter, the PTI value of the mixture was adjusted to 7. After standing, the supernatant liquid was removed by decantation, the precipitate was washed with water, the moisture was sufficiently removed by filtration, and the pigmented phosphor of the present invention was obtained by drying.

Example 3 0.5 parts by weight of carboxymethylcellulose was dissolved in water to prepare a 0.25% carboxymethylcellulose aqueous solution. In this 0.25% aqueous solution, the average particle size was 71t.
100 parts by weight of a copper-activated aluminum phosphor co-activated zinc sulfide green light-emitting phosphor (ZnS:C11', AI) was added and sufficiently uniformly dispersed using a stirrer until it became primary particles. In this way, a phosphor dispersion liquid was obtained.

On the other hand, 0.0035 parts by weight of carboxymethylcellulose was dissolved in water to prepare a 1,0035% aqueous solution.

In this 0.0035% aqueous solution, an average particle size of about 0.00
0.7 parts by weight of (Co O) +, s2.Al2O3 green pigment particles having a diameter of 8 μm were added and thoroughly dispersed with a ball mill until uniform. In this way, a pigment particle dispersion was obtained. Next, the phosphor dispersion and the pigment particle dispersion were mixed with stirring. Thereafter, water was sufficiently removed by filtration and then dried to obtain the pigmented phosphor of the present invention.

[Brief explanation of drawings]

Figure 1 shows favorable characteristics when attached to the surface of the phosphor (C
A graph showing the reflectance of oo)n and Al2O3, Figure 2 is a graph showing the spectral reflectance of the (Coo)n Al2O3 phosphor used in the present invention and a conventional green pigment, and Figure 3 is a graph showing the spectral reflectance of the (Coo)n Al2O3 phosphor used in the present invention and a conventional green pigment. FIG. 4 is a graph showing the specific reflectance of the phosphor of the present invention and the conventional phosphor.

Claims (8)

[Claims] (1) Pigmented green light-emitting device characterized in that (CoO)_n・Al_2O_3-based green pigment particles are attached to the surface of a green-light-emitting phosphor, and the following conditions (a) to (c) are satisfied. phosphor. (a) The value of n is 1.0≦n≦2.6. (b) The average particle diameter of the pigment is 0.001 to 0.1 μm. (2) The pigmented green light-emitting phosphor according to claim (1), wherein the value of n is within the range of 1.2≦n≦2.0. (3) A patent in which the reflectance of the (CoO)_n/Al_2O_3-based green pigment particles is within the area surrounded by curves a and b in Figure 1, when the reflectance of barium sulfate powder is 100%. A pigmented green light-emitting phosphor according to claim (1). (4) The pigmented green light-emitting phosphor according to claim (1), wherein the amount of green pigment particles attached is in the range of 0.01 to 3 weight percent based on the green light-emitting phosphor. (5) The matrix of the green light-emitting phosphor is zinc sulfide (ZnS), contains at least one of copper (Cu) and gold (Au) as an activator, and aluminum (Al) as a co-activator. ), chlorine (Cl), fluorine (F), bromine (Br)
, iodine (I), as claimed in claim (1). (6) The matrix of the green-emitting phosphor is zinc cadmium sulfide [
(Zn, Cd)S] phosphor, Cu as an activator
, Ag, and Au, and contains at least one of Al, Cl, F, Br, and I as a coactivator, according to claim (1). . (7) The green light-emitting phosphor is Zn_2SiO_4:Mn,
The pigmented green light-emitting phosphor according to claim (1), which is any one of Zn_2SiO_4:Mn, As, and ZnO:Zn. (8) The green light-emitting phosphor is Ln_2O_2S:Tb, Y
_3Al_2(AlO_4)_3:Tb, Y_2SiO
_5: The pigmented green light-emitting phosphor according to claim (1), which is any one of Tb. (However, Ln is Y, La
, at least one of Gd)