JPH048794A - Luminous composition - Google Patents

Abstract

PURPOSE:To obtain a luminous composition having sufficient electrical conductivity and emission luminance under low-velocity electron ray excitation, by blending a fluorescent substance excited with low-velocity electron rays, having the surface coated with a (semi-)uniform filmy electrically conductive metal oxide, with a granular electrically conductive metal oxide or sticking the granular electrically conductive metal oxide to the fluorescent substance. CONSTITUTION:(A) A fluorescent substance excited with low-velocity electron rays shown by ZnS:M1,M2 (M1 is Ag, Zn, Cu, Au or Mn; M2 is Al, F, Cl, Br or I), (ZnCd)S:M1, M2, etc., having the surface coated with a (semi-)uniform filmy electrically conductive metal oxide such as In2O3 or SnO2 is blended with (B) a granular electrically conductive metal oxide such as In2O3 or SnO2 or the granular electrically conductive metal oxide is stuck to the fluorescent substance to give the objective luminous composition.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a luminescent composition that emits fluorescence when excited by a slow electron beam used in a fluorescent display tube, and particularly relates to a luminescent composition used in a fluorescent display tube. Regarding.

[Prior art] A low-speed electron beam-excited phosphor is used in a low-speed electron beam-excited fluorescent display tube (
This is a phosphor used for fluorescent display tubes (hereinafter referred to as fluorescent display tubes). A fluorescent display tube has a structure in which an anode plate with a fluorescent film on one side and a cathode facing the fluorescent film are sealed in a container, and the container is evacuated, and an acceleration voltage of 1 k is emitted from the cathode.
A fluorescent film on an anode plate is caused to emit light by a low-velocity electron beam of V or less.

The most important property required of the phosphor constituting the phosphor film of a fluorescent display tube is that the phosphor has electrical conductivity. If the conductivity is low, the surface of the fluorescent film of the anode will be negatively charged by the electron beam emitted from the cathode, making it impossible to emit light. Therefore, a number of techniques have been disclosed in the past to impart conductivity to the fluorescent film and release the increased charge. for example,
In Japanese Patent Publication No. 52-23911, ZnS:Ag
.

A light emitting composition is disclosed in which a blue light emitting phosphor such as Y2Sin, :Ce is mixed with 10% to 10% by weight of In2O3. In addition, in Japanese Patent Publication No. 62-53554, Zn
S:Ag, Zn (SSe):Ag, AID, 5rG
az S4: A light emitting composition is disclosed in which a blue light emitting phosphor such as Ce is mixed with In203, SnO2, etc. having a defined particle size. In these technologies, since the base material phosphor does not have electrical conductivity, conductivity is imparted to the phosphor and its fluorescent film by mixing a conductive metal oxide such as In2O3 or 5n02 with the phosphor. , which improves the brightness of fluorescent display tubes.

However, the above-mentioned conductive metal oxide (hereinafter referred to as a conductive substance) is a non-luminescent substance and has a yellow or brown body color. For this reason, the above-mentioned technique of mixing a large amount of them with a phosphor to form a luminescent composition results in the conductive substance inhibiting and absorbing the luminescence of the phosphor.
This has the disadvantage that it causes a reduction in the brightness of the fluorescent display tube. Attempts have been made to overcome these drawbacks by controlling the amount of conductive material mixed in the luminescent composition, but these attempts have been insufficient. In particular, with the recent rapid development of display devices, higher brightness fluorescent display tubes are desired.

[Problems to be Solved by the Invention] The present invention has been made in view of the above-mentioned circumstances, and is an object of the present invention to provide a light emitting device that exhibits sufficient conductivity and luminance under slow electron beam excitation at an accelerating voltage of 1 kV or less, especially 100 V or less. The purpose is to provide a composition.

[Means for Solving the Problem] In order to improve the brightness of a fluorescent display tube, the present inventors have developed various types of conductive substances contained in a luminescent composition, methods of adding them to the phosphor, amount of addition, etc. As a result of extensive research, we found that by coating the entire surface of the phosphor with a conductive metal oxide film in the form of a homogeneous or semi-homogeneous film, and then mixing or attaching an appropriate amount of conductive metal oxide to this, The inventors have discovered that the brightness of a luminescent composition is dramatically improved under low-speed electron beam excitation, and have accomplished the present invention.

The light-emitting composition of the present invention comprises a slow electron beam excited phosphor whose entire surface is coated with a conductive metal oxide in the form of a homogeneous or semi-homogeneous film, and a granular conductive material mixed or attached to the phosphor. It is characterized by containing a metal oxide.

The state in which the phosphor is coated with a homogeneous film-like or semi-homogeneous film-like conductive material is a state in which the phosphor and the conductive material are covered with dots, as in a conventional luminescent composition in which particulate conductive material is mixed. Unlike the state in which they are in contact, this refers to a state in which the phosphor and the conductive substance are connected in a plane. Therefore, there may be cases where some lumps of deposits are included or the deposits are uneven.

As the phosphor used in the luminescent composition of the present invention, generally well-known slow electron beam excited phosphors can be used. For example, blue-emitting phosphors include silver-activated zinc sulfide (ZnS:Ag), cerium-activated yttrium silicate (Y2 S l 205 ), self-activated calcium tungstate (CaWO4), and green-emitting phosphors such as Copper-activated zinc sulfide (2nS: Cu), copper-activated zinc cadmium sulfide ((ZnCd)S: Cut
, terbium-activated rare earth oxysulfide (Ln202S:
Tb), manganese-activated zinc silicate (Zn2SiOa
), phosphors such as europium-activated yttrium oxysulfide (Y2O2S:ELJ), copper-activated zinc cadmium sulfide f (ZnCd):Cu1, and the like can be used.

In particular, the phosphor is preferably at least one selected from the group consisting of phosphors represented by the general formula ZnS:M, M2 or the general formula (ZnCd)S:M+, M2. However, Ml is at least one element selected from the group consisting of Ag, Zn, Cu, and Au, and M2 is at least one element selected from the group consisting of ANSF, C47, Br, and I. When such a phosphor is used in a fluorescent display tube, the brightness tends to be particularly good. The color of the emitted light is determined by M in the general formula above.
It can be freely changed by changing the types and amounts of L, M2, and the amount of Cd added.

For example, by changing the types of Ml and M2, (ZnS:Ag
, A, l, (ZnS:Zn,CN) and ((ZnCd
)S:Ag, Cl71, etc. are blue-emitting phosphors, (ZnS
: Cu, CD), (ZnS:Cu.

Au, AII) and f (ZnCd)S: Ag, A
111 etc. are green phosphors, (ZnS:Au, AN), (Z
nS: Cu, Au, A11) and ((ZnCd)S
:Ag, CI! The first prize was a yellow-emitting phosphor, (ZnS:Z
n, C(l and (ZnCd)S: Ag, Cu, ANI(
ZnS: Ag, AJ and ZnS: Au, Al
mixture of l) and f (ZnCd)S: Ag, Au
, Al 1, etc. are white-emitting phosphors, t (ZnCd)S
: Cu.

Cl3) f(ZnCd)S: Au, ANI
((ZnCd)S:Ag,C1)l and ZnS:
Mn, etc. are orange-emitting phosphors, ((ZnCd)S:
CuAl1 l ((ZnCd)S + Au, A
D ((ZnCd)S: Ag, Al l and (Z
nCd)S:Mn, etc. are used as red-emitting phosphors.

Homogeneous film-like or semi-homogeneous film-like conductive metal oxides and granular conductive metal oxides include, for example, In2O3, SnO
2, ZnO, TiO2, WO3 or Nb2O, etc. can be used, and In2O3 or SnO2 is particularly preferred because of its excellent electrical conductivity.

The volume average particle diameter of the granular conductive metal oxide is preferably 0.05 μm or more and 2.0 μm or less.

The coating amount of the homogeneous film-like or semi-homogeneous film-like conductive metal oxide and the granular conductive metal oxide is 0.01 to 0.01 of the amount of the phosphor.
The content of the particulate conductive metal oxide is preferably 5.0% by weight, and the content of the granular conductive metal oxide is 0.5 to 10% by weight of the phosphor.
It is preferable that

The following method can be used to form a homogeneous or semi-homogeneous film of metal oxide on the surface of the phosphor.

The first method includes forming a homogeneous or semi-homogeneous film of a conductive metal oxide on the surface of the phosphor by sputtering or vapor deposition.

The second method is to use organic compounds such as In, 5nSTi, and W that can easily become conductive substances by heating and oxidizing, such as trimethylindium (■), tris(cyclopentagenyl)indium, triphenylindium, and diethyltin. , dipropyltin, diphenyltin, trichloromethyltitanium, tetrabenzyltitanium, hexamethyltungsten, dichlorotrimethylniobium, etc. are dissolved in a suitable organic solvent such as lower alcohol such as methanol or ethanol, ether, etc., or these metal ions are dissolved in an ionic group. Examples include a method using a solution extracted into an organic solvent as a combined or chelated compound. Specifically, the phosphor is first dispersed in these solutions, and then heated to volatilize the organic solvent, so that the organometallic compound is almost uniformly adhered to the surface of the phosphor.

Next, the obtained phosphor was fused in air or a weakly reducing atmosphere for 4 hours.
By firing at a temperature of 50° C. or higher, the organic compound is decomposed, and the metal oxide coats the surface of the phosphor in a homogeneous or semi-homogeneous film.

As a third method, by heating and oxidizing the same as those used in the second method, metals that can easily become conductive substances are prepared in an aqueous solution or in a water-soluble organic solvent with nitrates, sulfates, and One possible method is to attach it as a chloride to the surface of the phosphor. For example, to coat as a nitrate, the nitrate of the metal is dissolved in an aqueous solution, the phosphor is suspended in the resulting aqueous solution, and the water is evaporated by heating.

By firing the obtained phosphor at 450°C or higher,
A low-speed electron beam-excited phosphor whose surface is coated with a conductive metal oxide in the form of a homogeneous or semi-homogeneous film is obtained.

In addition to the above methods, there are also methods used in other industrial fields, such as! A method of manufacturing a conductive film of TO (indium lead oxide) may be used.

By forming a homogeneous or semi-homogeneous conductive metal oxide film on the surface of the phosphor in this manner, and further adhering or mixing granular conductive metal oxide, the luminescent composition of the present invention can be produced. is obtained.

As a method for attaching the particulate conductive metal oxide, the same method as the method for attaching a pigment to a phosphor for a cathode ray tube can be applied. For example, a slow electron beam excited phosphor and a conductive metal oxide are suspended in water, and a commonly used organic binder such as a combination of urea resin emuldisin and gelatin or gelatin and gum arabic, or an acrylic resin emulsion is added, By attaching a conductive metal oxide to a phosphor, separating and drying it, a phosphor to which particulate conductive metal oxide is attached can be obtained.

Using the luminescent composition thus obtained, a fluorescent display tube can be manufactured using a conventional method. for example,
First, a paste is formed by mainly kneading a luminescent composition and a binder, and then the paste is coated using a conventional coating method such as a screen coating method, an electrodeposition coating method, or a precipitation coating method, usually in an amount of 5 to 30 mg. / cm 2 on the anode plate. After drying the plate, it is fired at 450° C. or higher to form a fluorescent film on the anode plate.

Thereafter, the anode plates are placed opposite each other at a regular distance to form a pair of electrodes, and the electrodes are sealed in a container made of glass or the like, and when the degree of vacuum reaches 10-'Torr or more, the exhaust is stopped and the container is sealed. After that, the sealing getter is removed and the internal vacuum level is further increased to obtain a fluorescent display tube. Also,
Instead of the luminescent composition, an aqueous solution containing a phosphor and metal nitrates, sulfates, chlorides, organic compounds, etc. that can easily become conductive metal oxides by heating and oxidation is used, and these are used as a binder. A phosphor film can also be formed by mixing with the above to form a paste, applying this paste onto an anode plate, and baking it at 450° C. in the same manner.

In the luminescent composition of the present invention, the amount of conductive metal oxide coated on, attached to, or mixed with the phosphor is closely related to the luminance of the fluorescent display tube using the luminescent composition and the phosphor film using the same. be. In the case of a conductive metal oxide in the form of a homogeneous film or a semi-homogeneous film, the coating amount is preferably 0.0% relative to the amount of phosphor.
01 to 5.0% by weight, more preferably 0.05 to 3% by weight
．． In the case of granular conductive metal oxide, the amount added is 0.5 to 10.0 fEJi based on the amount of phosphor.
It is in the range of 1%. Further, the particulate conductive metal oxide is
It is more preferable to have an average particle size of 0.1 to 2.0 μm.

[Function] In the luminescent composition of the present invention, the surfaces of the phosphor particles are coated with a conductive metal oxide in the form of a homogeneous or semi-homogeneous film, and the phosphor particles are further coated with a granular conductive metal oxide. Mixed or attached.

Due to the presence of these film-like and granular 2Fi conductive metal oxides, it is possible to excite and emit high-intensity light even with a low driving voltage, that is, even with a low-speed electron beam.

On the other hand, due to the presence of particulate conductive metal oxides, the amount of coating of film-like conductive metal oxides is small, so the electron beam can easily reach the phosphor without being hindered by it, resulting in a decrease in brightness. That's not true.

[Example] Hereinafter, the functions and effects of the present invention will be described with reference to the drawings.

FIG. 1(a) and FIG. 1(b) are electron micrographs showing the structure of the luminescent composition particles of the present invention. Figure 1 (a
) is 1.0 for the blue-emitting phosphor (ZnS:Ag, AN).
Figure 1(b) shows the structure of slow electron beam-excited phosphor particles coated with a uniform or semi-uniform film of % In2O3.
1 shows the structure of particles of the luminescent composition of the present invention obtained by dry mixing granular In2O3 with the phosphor of FIG. 1(a).

The phosphor of the present invention has a structure in which a uniform film or semi-uniform film of conductive metal oxide is formed on the surface of the phosphor as shown in FIG. 1(a), and granular In2O3 is further mixed therein. have

Figure 2 shows a blue-emitting phosphor (ZnS:Ag, Ag) coated with 25% by weight of In2O in the form of a homogeneous film, which is coated with a slow electron beam excited phosphor, and further coated with granular particles with an average particle size of 1 μm. Luminescent composition (a) according to the present invention dry-mixed with 5.0% by weight of In2O3, 2.5% by weight of 1n2 in the form of a homogeneous film
A slow electron beam excited phosphor (b) coated with In20i and In20i having an average particle size of 3 μm was added to the blue-emitting phosphor using 1.
0% by weight dry mixed conventional luminescent composition (C) and In
The conventional luminescent composition (d) obtained in the same manner as the luminescent composition (C) except that 10.0% by weight of O, , FIG. 3 is a graph diagram showing the relationship between the driving voltage and the relative luminance when changing the luminance. In addition, the relative brightness is the luminous brightness when a fluorescent display tube mounted with the luminescent composition (d) is driven at 50 V, which is 100? Expressed as o.

As is clear from Fig. 2, the fluorescent display tube mounted with the coated slow electron beam-excited phosphor (b) of In 203 does not emit light due to its excellent conductivity in the low driving voltage range of 70V or less. The starting voltage is lower, and the brightness is higher than that of a fluorescent display tube equipped with the conventional luminescent composition (d). However, when the driving voltage exceeds 70 V, the luminance is no different from that of a fluorescent display tube equipped with the luminescent composition (b) because the luminescent composition (d) has superior conductivity. On the other hand, a fluorescent display tube equipped with the luminescent composition (a) according to the present invention is coated with a conductive metal oxide in the form of a homogeneous or semi-homogeneous film,
And by mixing in granular form, a material coated with a conductive metal oxide (luminescent composition (b)) and a material coated with a conductive metal oxide (luminescent composition (b)) are obtained.
Luminescent composition (C).

By taking advantage of the feature (d), high luminance can be maintained even in a high driving voltage range.

Figure 3 shows that a blue-emitting phosphor (ZnS:Ag, Ag) is coated with In2O3 at 0.1.1.0.2°0.5.0 weight 96, and then the average The relative brightness is shown when granules 1n203 having a particle diameter of 1.0 μm are mounted in a fluorescent display tube with varying mixing amounts and emitted under the condition of a driving voltage of 50V. The relationship between the added amount of In20), which is the sum of the yi amount and the mixed amount, and the relative brightness is shown by a solid line in FIG. Also, for reference, In2O3
The dashed line shows the relative brightness when the coating amount of blue-emitting phosphor coated on a homogeneous film of granular Indium with an average particle size of 3 μm is
The relative brightness when the mixing amount of 2O3 is changed is represented by a dashed line and shown in the same graph.

Note that the relative brightness is I n 2.03 compared to the phosphor.
This is the relative brightness when the brightness of a fluorescent display tube mounted with a conventional light-emitting composition dry-mixed at 0% by weight is taken as 100%.

Moreover, FIG. 4 shows red light emitting phosphor 1 (ZnCd)S:Cu
, CNI, and I n203 to 0°05.
0.2.0 and 5.2.0% by weight of the low-speed electron beam-excited phosphors were coated with granular In2O in varying amounts and mounted on fluorescent display tubes under the condition of a driving voltage of 50V. Shows the relative brightness when emitting light. The relationship between the amount of In2O3 added and the relative brightness is shown by a solid line in FIG. Also,
For reference, the dashed line shows the relative brightness of a blue-emitting phosphor coated with a homogeneous film of In2O3 when the thickness of the blue light-emitting phosphor is varied. The dashed line represents the relative brightness when the mixing amount is changed, and is shown in the same graph. In addition,
The relative luminance is the luminance when the luminance of a fluorescent display tube mounted with a conventional luminescent composition in which 10% by weight of In 20's is dry mixed with the phosphor is taken as 100%.

As is clear from FIGS. 3 and 4, in order to start emitting light, it is necessary to add a large amount of In2O3, or the fluorescent display tube equipped with the luminescent composition of the present invention has only a small amount of film. The coating of granular In2O3 also starts to emit light, and the granular 1
The brightness increases by mixing n203.A luminescent composition in which granular In2O3 is mixed with a film-like In2O or a 10% by weight coated slow electron beam-excited phosphor is non-luminescent. Since the substance In2O absorbs the light emitted by the phosphor and the amount of phosphor per unit area on the anode plate of the fluorescent display tube decreases, a large increase in brightness cannot be expected. Therefore, in the luminescent composition of the present invention, the combination of the coating amount of the film-like conductive material and the mixing amount of the particulate conductive material is such that the film-like conductive material is 0.
It is more preferable to mix 1.0 to 5.0 weight % of particulate conductive material to the slow electron beam excited phosphor coated with 0.05 to 3.0 weight %.

Next, FIG. 5 shows a blue-emitting phosphor (ZnS:Ag, (1
), each of the light-emitting compositions of the present invention, in which the particle size of In2O, which fluoresces when excited by a slow electron beam, is temporarily coated with In2031n2031% by weight, is mounted on a fluorescent display tube, and its brightness is measured. FIG. 3 is a graph diagram showing the relationship between relative brightness and average particle size. As is clear from FIG. 5, it is found that in the luminescent composition of the present invention, the average particle size of the conductive metal oxide to be mixed is preferably 0.1 to 2 μm.

From the above, by coating the phosphor with a film-like conductive metal oxide, it becomes possible to start emitting light even at a low driving voltage, and it is possible to emit high brightness.

However, in light-emitting compositions in which the surface of the phosphor is coated with a film of conductive metal oxide, as the amount of conductive oxide increases,
The film acts as a barrier for the electron beams emitted from the cathode, making it difficult for them to reach the phosphor, resulting in a decrease in brightness.

On the other hand, conventional luminescent compositions containing only particulate conductive metal oxides have little barrier effect against electron beams;
Because it is highly efficient as a conductive substance, it tends to be effective only when added in large amounts.

Therefore, the luminescent composition of the present invention improves brightness by forming a film of a conductive material within a range where the barrier effect is small and supplementing it with granular conductive material to take advantage of the characteristics of both.

Various examples of the present invention will be shown below.

Example 1 An In2O target was installed in a sputtering device, and In2O was placed on the surface of 50 g of green light emitting phosphor (ZnS:Cu, AI)
O3 sputtering was performed.

Sputtering was performed until the amount of the In2O film deposited on the phosphor was 1% by weight to obtain a low-speed electron beam excited phosphor.

Furthermore, this phosphor has an average particle size of 1. Otlm's In2O
The green light-emitting composition of the present invention was obtained by adding 8.0% by weight of the three phosphors and sufficiently dry mixing. Next, 5. O heavy jEi 9j PVA aqueous solution 3
0. After adding and sufficiently kneading, the mixture was screen coated onto a 1c+n2 metal anode plate supported on a ceramic substrate and dried.

The anode plate and ceramic substrate were heated to 450"C for 3 hours.
The PVA was decomposed by baking for 0 minutes to obtain a fluorescent film. Further, a cathode of a tungsten wire heater coated with oxides of calcium, strontium, and barium was placed at a distance of about 5 mm from the fluorescent film, and these pair of electrodes were placed in a glass container. The inside of the glass container was evacuated and the glass container was sealed at a pressure of about 10-' Torr, and then the vacuum was increased by blowing off the container to obtain a fluorescent display tube.

Further, as Comparative Example 1, a similar green-emitting phosphor was prepared with an average particle size of 4. A conventional luminescent composition was prepared by mixing 10% by weight of czm In2O, and a fluorescent display tube was prepared in the same manner. These fluorescent display tubes have an anode plate voltage (driving voltage) of 50 V, a cathode voltage of 1.2 V, and a current density of 2 mA/(1).
Assuming that the luminance of a fluorescent display tube equipped with a conventional slow electron beam-excited green-emitting phosphor is 1009 ci, the luminance of a fluorescent display tube equipped with a green-emitting composition of the present invention is as follows. It was 170%.

Example 2 After using the SnO2 target, the same procedure as in Example 1 was carried out to prepare a blue-emitting phosphor (ZnS.Ag).

AN) A uniform coating of 1.0% by weight of SnO2 is formed on 50g, and 7.0% by weight of SnO2 with an average particle size of 1.0 μm is mixed with respect to the amount of blue-emitting phosphor. A luminescent composition was obtained. In addition, as Comparative Example 2, fluorescent display tubes were made using a conventional blue light-emitting composition mixed with SnO2 having an average particle size of 3 μm in the same manner as in Example 1, and emitted light. Assuming that the brightness of a fluorescent display tube equipped with a line-excited blue light-emitting composition is 100%,
The luminance of the fluorescent display tube equipped with the blue light emitting composition of the present invention was 165%.

Example 3 In2O, 5% by weight in terms of S
Atron N1n (trademark manufactured by Nippon Soda ■) containing 0.5% by weight in terms of nO2 was used.

Dissolve 20 g of Kuko's Atron NIn in 100 ml of ethanol, and add yellow-emitting phosphor f (ZnCd) to this ethanol.
)S:Ag, AD)Icier was added and sufficiently suspended, and then heated to 60°C to volatilize the ethanol.

This phosphor was taken out and fired in air at 500°C for 1 hour, and then In2O3 was 1.5% compared to the yellow-emitting phosphor.
A slow electron beam-excited yellow-emitting phosphor coated with a homogeneous film of conductive metal oxide containing 0% by weight and 0.1% by weight of SnO2 was obtained.

The obtained slow electron beam-excited yellow-emitting phosphor was further mixed with 1n203 in an amount of 5.0% by weight based on the initial yellow-emitting phosphor to obtain a yellow-emitting composition of the present invention.

As Comparative Example 3, a conventional yellow-emitting phosphor was prepared by mixing 10.0% by weight of In2O with an average particle size of 4 μm in the same yellow-emitting phosphor as in Example 3.

Fluorescent display tubes were prepared in the same manner as in Example 1 using 50 g of each of these slow electron beam-excited yellow luminescent compositions, and the luminance was measured. If the brightness of the tube is 100%,
The luminance of the fluorescent display tube equipped with the luminescent composition of the present invention is 1
It was 60%.

Example 4 Blue-emitting phosphor (ZnS: Ag, AN) and yellow-emitting phosphor (ZnS: Au, Aj!) in a ratio of 1:2
Prepare 100 g of a white luminescent composition mixed in a weight ratio of
Using Atron Nln in the same manner as in Example 3, 1.0% by weight of In2O3 and 5n02 were added to the white light emitting composition.
is 0. A slow electron beam excited white luminescent composition coated with 1% by weight was obtained.

In2O having an average particle size of 1 μm was mixed into the obtained luminescent composition in an amount of 5.0% by weight based on the initial white luminescent composition to obtain a slow electron beam-excited white luminescent phosphor of the present invention.

As Comparative Example 4, a white light emitting composition was prepared by mixing the same white light emitting phosphor as in Example 4 with 10% by weight of In2O having an average particle size of 4 μm.

Fluorescent display tubes were prepared in the same manner as in Example 1 using 50 g of each of these slow electron beam-excited yellow luminescent compositions, and the luminance was measured. If the brightness of the tube is 10096,
The luminance of the fluorescent display tube equipped with the luminescent composition of the present invention is 1
It was 55%.

Example 5 Red-emitting phosphor t (ZnCd)S: Cu, CD
1100 g was added to 50 ml of water and thoroughly stirred.

This suspension contained 11.0% by weight of In in terms of In2O3.
20 g of an aqueous solution of (SO4)i was added, and the mixture was thoroughly stirred again, and then left to stand and heated to 80° C. to evaporate water. The dried phosphor was fired at 500° C. to obtain a low-speed electron beam-excited red-emitting phosphor.

As Comparative Example 5, 5.0% by weight of In2O3 with an average particle size of 4 μm was mixed with the same red-emitting phosphor as in Example 5,
A red-emitting phosphor excited by slow electron beam was obtained.

A fluorescent display tube was prepared in the same manner as in Example 1 using 50 g of each of these phosphors, and the brightness was measured. %, the luminance of the fluorescent display tube equipped with the luminescent composition of the present invention was 150%.

Example 6 Orange-emitting phosphor 1 (ZnCd) S:Cu, CD1100
g was added to 50 ml of ethanol and thoroughly stirred.

This suspension had an In2O3 equivalent content of 10% by weight.
After adding 20 g of an aqueous solution of (NO3) 3 .3H20 and stirring thoroughly again, the mixture was allowed to stand and heated to 50° C. to evaporate ethanol and water.

The thus dried phosphor was fired at the same <500'C, and the average particle size was 1. Oμrn In2O, 4゜0 fold I
% dry mixing to obtain a slow electron beam-excited orange-emitting phosphor according to the present invention.

As Comparative Example 6, 5.0% of In2O with an average particle size of 4 μm was added to the same red-emitting phosphor as in Example 6. A low-speed electron beam-excited orange-emitting phosphor was obtained by mixing 0% by weight.

A fluorescent display tube was prepared in the same manner as in Example 1 using 50 g of each of these phosphors, and the brightness was measured. %, the luminance of the fluorescent display tube equipped with the luminescent composition of the present invention was 165%.

As mentioned above in Examples 1 to 6, when the luminescent composition of the present invention is used, even under low-speed electron beam excitation of 50V, an excellent product with higher brightness than conventional luminescent compositions can be obtained. A fluorescent display tube is obtained.

[Effects of the Invention] As explained above, according to the present invention, by coating the surface of the phosphor with a conductive metal oxide in the form of a homogeneous film or a semi-homogeneous film, the emission starting voltage is reduced, and is lower than 1 kV, especially 10
A phosphor having sufficient conductivity and luminance can be obtained under low-speed electron beam excitation of 0 V or less, and the luminance can be further improved by mixing granular conductive metal oxide.

Furthermore, according to the present invention, a light-emitting composition can be obtained that does not have high brightness and exhibits characteristics equivalent to or better than conventional slow electron beam excited phosphors in terms of coating characteristics on an anode plate, deterioration of the phosphor, etc. .

Furthermore, the luminescent composition according to the present invention can be applied not only to fluorescent display tubes but also to the fluorescent screen of thin cathode ray tubes. Furthermore, when a lamp phosphor is used as the phosphor used as a raw material, it can also be used as a light-emitting composition for a rapid-start type fluorescent lamp, which requires a phosphor having conductivity.

[Brief explanation of drawings]

FIG. 1(a) shows that in the luminescent composition according to the present invention,
Electron micrograph showing the state of the luminescent composition particles with a semi-uniform film formed on the surface of the conductive metal oxide, Figure 1 (b
) is an electron micrograph showing the state of the luminescent composition particles in which the conductive metal oxide particles are attached to the non-surface of a semi-homogeneous film of the conductive metal oxide in the luminescent composition according to the present invention;
FIG. 2 is a graph showing the relationship between driving voltage and relative luminance according to an example of the present invention and a comparative example, and FIG. 3 is a graph showing the relationship between driving voltage and relative luminance according to another example and comparative example of the present invention. A graph showing the relationship between luminescence brightness, FIG. 4 is a graph showing the relationship between driving voltage and relative luminance according to still another example of the present invention and a comparative example, and FIG. 5 is a graph showing the relationship between relative brightness and average particle size. It is a graph diagram showing the relationship between. Applicant's agent Patent attorney Takehiko Suzue Figure 1 Procedure amendment (method) % formula%

Claims (5)

[Claims] (1) A low-speed electron beam-excited phosphor whose surface is coated with a conductive metal oxide in the form of a homogeneous or semi-homogeneous film, and a granular conductive metal oxide mixed or attached to the phosphor. A luminescent composition comprising. (2) The phosphor has the general formula ZnS:M_1,M_2(
However, M_1 is at least one element selected from the group consisting of Ag, Zn, Cu, Au, and Mn;
2 is at least one element selected from the group consisting of Al, F, Cl, Br and I. ) and a phosphor represented by the general formula (ZnCd)S:M_1M_2 (M_1 and M_2 are the same as above). 1. The luminescent composition according to 1. (3) The homogeneous film-like or semi-homogeneous film-like conductive metal oxide and granular conductive metal oxide include In_2O_3 and S
The luminescent composition according to claim 1 or 2, characterized in that it is at least one selected from the group consisting of nO_2. (4) The volume average particle size of the granular conductive metal oxide is 0
, 05 μm or more and 2.0 μm or less. (5) The coating amount of the homogeneous film-like or semi-homogeneous film-like conductive metal oxide is 0.01 to 5.0% by weight of the amount of the phosphor, and the content of the particulate conductive metal oxide is , 0.5 to 10% by weight of the phosphor, the luminescent composition according to any one of claims 1 to 4.