JPH0717899B2 - Luminescent composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a luminescent composition used in a fluorescent display tube, which emits fluorescence when excited by a low-speed electron beam, and particularly to a luminescent composition used for a fluorescent display tube. Regarding

[Prior Art] A slow electron beam excited phosphor is a phosphor used for a slow electron beam excited fluorescent display tube (hereinafter referred to as a fluorescent display tube). A fluorescent display tube has a structure in which an anode plate having a fluorescent film on one surface and a cathode facing the fluorescent film are enclosed in a container, and the inside of the container is evacuated, and an accelerating voltage of 1 k emitted from the cathode.
The phosphor film on the anode plate is caused to emit light by a slow electron beam of V or less.

The most important characteristic required for the phosphor forming the fluorescent film of the fluorescent display tube is that the phosphor has conductivity. If the conductivity is low, the surface of the fluorescent film of the anode is negatively charged by the electron beam emitted from the cathode, which makes it impossible to emit light. Therefore, various techniques have been disclosed in the past for imparting conductivity to the fluorescent film and allowing the increased electric charge to escape. For example,
Japanese Patent Publication No. 52-23911 discloses a light emitting composition in which a blue light emitting phosphor such as ZnS: Ag or Y ₂ SiO ₅ : Ce is mixed with 10 to 90% by weight of In ₂ O ₃ . In addition, Japanese Examined Japanese Patent Sho 62-53554
In the publication, blue light emitting phosphors such as ZnS: Ag, Zn (SSe): Ag, Al, and SrGa ₂ S ₄ : Ce are mixed with In ₂ O ₃ , SnO _{2 and the} like having a defined particle size. The thing is disclosed. In these technologies, since the base phosphor is not conductive, In
_By mixing a conductive metal oxide such as ₂ O ₃ or SnO ₂ with the phosphor, conductivity is imparted to the phosphor and its phosphor film, and the brightness of the fluorescent display tube is improved.

However, the above-mentioned conductive metal oxide (hereinafter referred to as a conductive substance) is a non-luminous substance and has a yellow or brown body color. For this reason, the above technique of mixing them with a phosphor in a large amount to form a light emitting composition is because the conductive substance inhibits and absorbs the emission of the phosphor,
There is a drawback that the brightness of the fluorescent display tube is lowered. Although such drawbacks have hitherto been attempted to be solved by adjusting the mixing amount of the conductive substance in the light emitting composition, they are still insufficient. In particular, with the recent rapid development of display devices, fluorescent display tubes with higher brightness are desired.

[Problems to be Solved by the Invention] The present invention has been made in view of the above circumstances, and emits light having sufficient conductivity and emission brightness with an accelerating voltage of 1 kV or less, particularly 100 V or less of low-speed electron beam excitation. It is intended to provide a composition.

[Means for Solving the Problems] In order to improve the brightness of the fluorescent display tube, the present inventors have studied the types of various conductive substances contained in the light emitting composition, the addition method to the phosphor, the addition amount, and the like. As a result of repeated intensive research, by coating the entire surface of the phosphor with a conductive metal oxide film in a homogeneous film form or a semi-homogeneous film form, and then mixing or adhering an appropriate amount of the conductive metal oxide film thereto, The inventors have found that the brightness of the light-emitting composition is dramatically improved under low-speed electron beam excitation, and completed the present invention.

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

The homogeneous film-like or semi-homogeneous film-like conductive substance covering the phosphor means that the phosphor and the conductive substance are the same as in the conventional luminescent composition in which the granular conductive substance is mixed. Unlike the state in which they are in contact with each other, it means the state in which the phosphor and the conductive substance are connected by a surface. Therefore, there may be a case where a part of lump-like adhered matter is included or unevenly adhered.

As the phosphor used in the light emitting composition of the present invention, a generally well-known slow electron beam excited phosphor can be used. For example, as the blue-emitting phosphor, silver activated zinc sulfide (ZnS: Ag), cerium activated yttrium silicate (Y ₂ Si)
₂ O ₅ ), self-activated calcium tungstate (CaWO ₄ ).
As a green light emitting phosphor, copper activated zinc sulfide (ZnS: C
u), copper activated zinc cadmium sulfide {(ZnCd) S: Cu}, terbium activated rare earth oxysulfide (Ln ₂ O ₂ S: Tb), manganese activated zinc silicate (Zn ₂ SiO ₄ ), etc., red Europium activated yttrium oxysulfide (Y ₂ O ₂ S: Eu),
A phosphor such as copper activated zinc cadmium sulfide {(ZnCd): Cu} can be used.

In particular, the phosphor has the general formula ZnS: M ₁ , M ₂ or the general formula (ZnC
d) It is preferably at least one selected from the group consisting of phosphors represented by S: M ₁ and M ₂ . However, M ₁ is Ag,
It is at least one element selected from the group consisting of Zn, Cu and Au, and M ₂ is at least one element selected from the group consisting of Al, F, Cl, Br and I. When such a phosphor is used in a fluorescent display tube, the brightness tends to be particularly good. The emission color is M ₁ , M ₂ in the above general formula.
It can be freely changed by changing the kind and addition amount of Cd and the addition amount of Cd. For example, due to changes in the types of M ₁ and M ₂ , (ZnS: Ag, Al), (ZnS: Zn, Cl) and {(ZnCd) S: Ag, Cl} are blue-emitting phosphors, (ZnS: Cu, C
l), (ZnS: Cu, Au, Al) and {(ZnCd) S: Ag, Al} are green phosphors, (ZnS: Au, Al), (ZnS: Cu, Au, Al) and {(Z
nCd) S: Ag, Cl} and the like are yellow-emitting phosphors, {ZnS: Zn, Cl and (ZnS: Zn, Cl
nCd) S: Ag, Cu, Al}, {ZnS: Ag, Al and ZnS: Au, Al mixture} and {(ZnCd) S: Ag, Au, Al} are white-emitting phosphors,
{(ZnCd) S: Cu, Cl}, {(ZnCd) S: Au, Al}, {(ZnC
d) S: Ag, Cl} and ZnS: Mn are orange-emitting phosphors, {(ZnC
d) S: Cu, Al}, {(ZnCd) S: Au, Al {(ZnCd) S: Ag, Al}
And (ZnCd) S: Mn are used as the red-emitting phosphor.

Examples of the homogeneous film-like or semi-homogeneous film-like conductive metal oxides and granular conductive metal oxides include In ₂ O ₃ , SnO ₂ , ZnO,
TiO ₂ , WO _3, Nb ₂ O ₅ or the like can be used, and In ₂ O ₃ or SnO ₂ is particularly preferable because it has excellent conductivity.

The volume average particle size of the granular conductive metal oxide is 0.05 μm or more 2.
It is preferably 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 5.0 of the phosphor amount.
The content of the granular conductive metal oxide is preferably 0.5 to 10% by weight of the phosphor.

In order to form a homogeneous film-like or semi-homogeneous film-like metal oxide on the phosphor surface, the following method can be used.

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

As a second method, organic compounds such as In, Sn, Ti and W, which can easily become conductive substances by heating and oxidizing, such as trimethylindium (III) tris (cyclopentadienyl) indium, triphenylindium. , Diethyltin, dipropyltin, diphenyltin,
Trichloromethyltitanium, tetrabenzyltitanium, hexamethyltungsten, dichlorotrimethylniobium and the like dissolved in a suitable organic solvent such as lower alcohols such as methanol and ethanol, ether or the like, or these metal ions as an ion associate or chelate compound. The method of using the solution extracted in the organic solvent is mentioned. Specifically, first, the phosphor is dispersed in these solutions, and then heated to volatilize the organic solvent, thereby causing the organometallic compound to adhere to the phosphor surface almost uniformly. Next, the organic compound is decomposed by baking the obtained phosphor at a temperature of 450 ° C. or higher in air or a weak reducing atmosphere, and the metal oxide covers the phosphor surface in a homogeneous film or semi-homogeneous film form. To do.

As a third method, by heating and oxidizing in the same manner as that used in the second method, a metal that can easily become a conductive substance is treated with nitrates, sulfates and salts in an aqueous solution or a water-soluble organic solvent. As a chloride, a method of attaching it to the surface of the phosphor can be mentioned. For example, to coat as a nitrate, the nitrate of the metal is dissolved in an aqueous solution, the phosphor is suspended in the obtained aqueous solution, and the water is evaporated by heating. By calcining the obtained phosphor at 450 ° C. or higher, a low-speed electron beam excitation phosphor in which the surface of the phosphor is coated with a conductive metal oxide in the form of a homogeneous film or a semi-homogeneous film can be obtained.

In addition to the above method, a method of manufacturing a conductive film of, for example, ITO (indium lead oxide) used in other industrial fields may be used.

In this way, a film of a conductive metal oxide in the form of a homogeneous film or a semi-homogeneous film is formed on the surface of the phosphor, and further, a granular conductive metal oxide is attached or mixed to give the luminescent composition of the present invention. Is obtained.

As the method for depositing the granular conductive metal oxide, the same method as the method for depositing the pigment on the 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 urea resin emulsion and gelatin or a combination of gelatin and gum arabic, or an acrylic resin emulsion is added, By attaching the conductive metal oxide to the phosphor, separating and drying the phosphor, the phosphor having the particulate conductive metal oxide attached thereto can be obtained.

Using the luminescent composition thus obtained, a trend display tube can be manufactured by a usual method. For example,
First, a paste in which the light-emitting composition and a binder are mainly kneaded is formed, and then the paste is usually used in an amount of 5 to 30 mg / cm by using a conventionally used coating method such as a screen coating method, an electrodeposition coating method, or a precipitation coating method. Apply to the anode plate in the range of ² . After the plate is dried, it is baked at 450 ° C. or higher to form a fluorescent film on the anode plate. After that, the anode plates are opposed to each other at a regular distance to form a pair of electrodes, and the electrodes are sealed in a container such as glass and the temperature is 10 ^-5 Torr.
When the above degree of vacuum is reached, the exhaust is stopped and sealing is performed. After that, the sealing getter is skipped to further increase the degree of vacuum inside, and a fluorescent display tube is obtained. Further, instead of the light-emitting composition, a phosphor and an aqueous solution in which a metal nitrate, a sulfate, a chloride, an organic compound, or the like, which can easily become a conductive metal oxide by being heated and oxidized, are used, It is also possible to form a paste by mixing with a binder to form a paste, apply the paste on an anode plate, and similarly bake at 450 ° C. to form a fluorescent film.

In the light emitting composition of the present invention, the amount of the conductive metal oxide coating, adhering to or mixing with the phosphor has a close relationship with the light emitting brightness of the fluorescent display tube using the light emitting composition and the fluorescent film using the same. is there. In the case of a homogeneous or semi-homogeneous film-like conductive metal oxide, the coating amount is preferably 0.01 with respect to the phosphor amount.
To 5.0% by weight, more preferably 0.05 to 3.0% by weight, and in the case of granular conductive metal oxide, the addition amount is 0.5 to 10.0% by weight based on the amount of the phosphor. Further, the granular conductive metal oxide more preferably has a radius particle diameter of 0.1 to 2.0 μm.

[Operation] In the light-emitting composition of the present invention, the surface of the phosphor particles is coated with a conductive metal oxide in the form of a homogeneous film or a semi-homogeneous film, and the phosphor particles are further coated with a granular conductive metal oxide. Mixed or adhered. The presence of these two kinds of conductive metal oxides, film-like and granular, enables high-luminance light emission by being excited by a low driving voltage, that is, by a low-speed electron beam.

On the other hand, due to the presence of the granular conductive metal oxide, the coating amount of the film-shaped conductive metal oxide can be small, so that the electron beam can easily reach the phosphor without lowering it and the brightness is reduced. Never.

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

1 (a) and 1 (b) are electron micrographs showing the structure of the luminescent composition particles of the present invention. FIG. 1 (a) shows a blue light emitting phosphor (ZnS: Ag, Al) containing 1.0% by weight.
FIG. 1B shows the structure of a slow electron beam excited phosphor particle coated with a uniform or semi-uniform film of In ₂ O ₃ , and FIG. 1B shows granular In ₂ O _{3 in} the phosphor of FIG. 1A. The structure of the luminescent composition particles of the present invention obtained by dry-mixing is shown. The phosphor of the present invention has a uniform metal film-like or semi-uniform film-like conductive metal oxide as shown in FIG.
It has a structure in which granular In ₂ O ₃ is mixed.

FIG. 2 shows a slow-electron-beam-excited phosphor coated with 2.5% by weight of a homogeneous film of In ₂ O _{3 on} a blue-emitting phosphor (ZnS: Ag, Al), and further with an average particle size of 1 μm. _2. Luminescent composition (a) according to the present invention in which 5.0% by weight of granular In ₂ O ₃ is dry mixed.
5 wt% of the homogeneous membrane of In ₂ O ₃ low voltage electron beam excitation phosphor coated with (b), wherein the In ₂ O ₃ having an average particle diameter of 3μm to blue-emitting phosphor, 1.0 wt% dry mixed with conventional The conventional light-emitting composition (d) obtained in the same manner as the light-emitting composition (c) except that the light-emitting composition (c) and the In ₂ O ₃ of 10.0 wt% were dry mixed were mounted on a fluorescent display tube. FIG. 6 is a graph showing the relationship between the drive voltage and the relative light emission brightness when the drive voltage (anode plate) is changed. The relative luminance is represented by assuming that the emission luminance when the fluorescent display tube having the light emitting composition (d) mounted thereon is driven at 50 V is 100%.

As is apparent from FIG. 2, the fluorescent display tube mounted with the In ₂ O ₃ -coated slow electron beam excitation phosphor (b) has excellent conductivity in a low driving voltage range of 70 V or less. The light emission starting voltage is low, and the brightness is higher than that of the conventional fluorescent display tube mounted with the light emitting composition (d). However, the drive voltage is 70V
Beyond the above, since the light emitting composition (d) is superior in conductivity, the brightness is not different from that of the fluorescent display tube mounted with the light emitting composition (b). On the other hand, the fluorescent display tube on which the light emitting composition (a) according to the present invention is mounted has a conductive metal oxide coated in a homogeneous film form or a semi-homogeneous film form, and is mixed in a granular form so as to have a conductive property. Utilizing the characteristics of the one coated with a metal oxide (light emitting composition (b)) and the one mixed with one (light emitting composition (c), (d), high emission brightness is maintained even in a high driving voltage range. be able to.

Fig. 3 shows In ₂ O ₃ for blue light emitting phosphor (ZnS: Ag, Al).
0.1%, 1.0%, 2.0%, 5.0% by weight of a low-speed electron beam excited phosphor, and granular In ₂ O ₃ having an average particle size of 1.0 μm was mixed and changed, and each was mounted on a fluorescent display tube and driven. Voltage 50
The relative luminance when light is emitted under the condition of V is shown. The relationship between the added amount of In ₂ O ₃ , which is the total of the coating amount and the mixing amount, and the relative luminance is shown by a solid line in FIG. Also, for reference, In ₂ O
The relative brightness when the coating amount of the blue light-emitting phosphor coated with the homogeneous film of ₃ was changed with a broken line, and the average In particle size of 3 μm
The relative brightness when changing the mixing amount of ₂ O ₃ is shown by a dashed line and is shown in the same graph. The relative brightness is a relative brightness when the brightness of a fluorescent display tube mounted with a conventional light emitting composition in which In ₂ O ₃ is dry mixed with a phosphor is 10% by weight is 100%.

In addition, FIG. 4 shows that the red light emitting phosphor {(ZnCd) S: Cu, Cl} is coated with 0.05, 0.2, 0.5 and 2.0% by weight of In ₂ O ₃ in the slow electron beam excited phosphor, and In ₂ O ₃ of the above are mounted on the respective fluorescent display tubes by changing the mixing amount, and the driving voltage is 50
The relative luminance when light is emitted under V conditions is shown. This In ₂ O ₃
The relationship between the amount of addition of R and the relative luminance is shown by the solid line in FIG. For reference, the relative brightness when the coating amount of the blue light emitting phosphor coated with a homogeneous film of In ₂ O ₃ is changed is a broken line, and the mixing amount of granular In ₂ O ₃ having an average particle diameter of 3 μm is changed. The relative brightness at that time is shown by a chain line and is shown in the same graph. The relative brightness is the brightness when the brightness of a fluorescent display tube mounted with a conventional light emitting composition in which In ₂ O ₃ is dry mixed with 10% by weight is 100%.

As is clear from FIGS. 3 and 4, a large amount of In ₂ O ₃ needs to be added to start light emission, but the fluorescent display tube mounted with the light emitting composition of the present invention has Light emission starts even with a small amount of film-like In ₂ O ₃ coating, and the brightness increases as the granular In ₂ O ₃ is mixed in sequence, but 10% by weight of film-like In ₂ O ₃ is coated. low voltage electron beam excitation phosphor emission composition comprising a mixture of in ₂ O ₃ of granular material which is in, in ₂ O ₃ is a non-luminescent material absorbs the light emitted from the phosphor, also on the anode plate of a fluorescent display tube Since the amount of phosphor per unit area decreases, a large increase in luminance cannot be expected. Therefore, in the luminescent composition of the present invention, the combination of the coating amount of the film-shaped conductive substance and the mixed amount of the granular conductive substance is
It is more preferable to add 1.0 to 5.0% by weight of the granular conductive material to the slow electron beam excited luminescent material coated with 0.05 to 3.0% by weight of the film-shaped conductive material.

Next, FIG. 5 shows the relationship between the blue emission phosphor (ZnS: Ag, Cl) and I
A slow electron beam excited phosphor coated with 1% by weight of n ₂ O ₃ was mounted on a fluorescent display tube with each light emitting composition of the present invention in which the particle size of the granular In ₂ O _{3 to be} mixed was changed. Measure the brightness,
It is a graph figure which shows the relationship between the relative brightness | luminance and average particle diameter. As is clear from FIG. 5, in the light emitting composition of the present invention, the average particle diameter of the conductive metal oxide mixed is 0.1 to
It can be seen that the thickness is preferably 2 μm.

From the above, by coating the phosphor with the film-shaped conductive metal oxide, it becomes possible to start light emission even at a low drive voltage, and high brightness can be emitted.

However, the light-emitting composition in which a film-shaped conductive metal oxide is coated on the surface of the phosphor has an increase in the amount of the conductive oxide,
On the contrary, the electron beam emitted from the cathode makes it difficult for the electron beam to reach the phosphor because the coating becomes a barrier, and the brightness tends to decrease. On the other hand, the conventional light-emitting composition in which only the granular conductive metal oxide is mixed has a small barrier effect against the electron beam, but since the effect as a conductive substance is high, the effect can be obtained unless added in a large amount. Tend not to.

Therefore, the light-emitting composition of the present invention forms a film of a conductive substance in a range having a small barrier effect, and further supplements the granular conductive substance to make use of the characteristics of both to improve the brightness.

Hereinafter, various examples of the present invention will be shown.

Example 1 An In ₂ O ₃ target was set in a sputtering apparatus, and In ₂ O ₃ was sputtered on the surface of 50 g of a green light emitting phosphor (ZnS: Cu, Al).

Sputtering was performed until the amount of the In ₂ O ₃ coating deposited on the phosphor was 1% by weight to obtain a low-speed electron beam excited phosphor.

Further, to this phosphor, 8.0 wt% was added to In ₂ O ₃ phosphor having an average particle diameter of 1.0 μm, and sufficiently dry mixed to obtain a green light emitting composition of the present invention. Next, 30 g of a 5.0 wt% PVA aqueous solution was added to this green light emitting composition, and after sufficiently kneading, screen coating was performed on a 1 cm ² metal anode plate indicated on the ceramic substrate, and drying was performed. The anode plate together with the ceramic substrate was baked at 450 ° C. for 30 minutes to decompose PVA and obtain a fluorescent film. Further, a cathode of a tungsten linear heater covered with oxides of calcium, strontium and barium was placed at a distance of about 5 mm from the phosphor film, and a pair of these electrodes was 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 ⁻⁵ Torr, and then the getter was blown to increase the degree of vacuum to obtain a fluorescent display tube.

Further, as Comparative Example 1, a conventional light emitting composition was prepared by mixing 10% by weight of In ₂ O ₃ having an average particle size of 4 μm with the same green light emitting phosphor, and a fluorescent display tube was prepared in the same manner. When these fluorescent display tubes were made to emit light under the conditions of an anode plate voltage (driving voltage) of 50 V, a cathode voltage of 1.2 V, and a current density of ² mA / cm ² , the fluorescent display mounted with a conventional slow-electron-beam-excited green-emitting phosphor. When the brightness of the tube was 100%, the brightness of the fluorescent display tube mounted with the green light-emitting composition of the present invention was 170%.

Example 2 The same procedure as in Example 1 except that the SnO ₂ target was used, and 1.0% by weight based on 50 g of the blue light emitting phosphor (ZnS: Ag, Al).
A uniform SnO ₂ film is formed, and S with an average particle size of 1.0 μm is formed.
7.0% by weight of nO ₂ was mixed with the amount of the blue light emitting phosphor to obtain a blue light emitting composition of the present invention. Further, as Comparative Example 2, a conventional blue light-emitting composition in which SnO ₂ having an average particle diameter of 3 μm was mixed was used, and a fluorescent display tube was produced in the same manner as in Example 1 to emit light. When the brightness of the fluorescent display tube mounted with the excited blue light emitting composition is 100%, the brightness of the fluorescent display tube mounted with the blue light emitting composition of the present invention is 165%.
Met.

Example 3 Atron NIn (trademark Nippon Soda Co., Ltd.) containing 5% by weight as In ₂ O ₃ and 0.5% by weight as SnO ₂ as an organic solvent-soluble metal compound capable of becoming a conductive metal oxide by thermal oxidation.
Manufactured) was used.

20 g of this Atron NIn is dissolved in 100 ml of ethanol, and the yellow light emitting phosphor {(ZnCd) S: Ag, Al} 100 is dissolved in this ethanol.
After adding g and suspending sufficiently, it was heated to 60 ° C. and ethanol was diffused.

This phosphor was taken out and baked in air at 500 ° C. for 1 hour, and then 1.0% by weight of In ₂ O ₃ was added to the yellow light-emitting phosphor.
A slow-electron-beam-excited yellow-emitting phosphor covered with a homogeneous film of a conductive metal oxide containing 0.1% by weight of SnO ₂ was obtained.

The obtained slow-electron-beam-excited yellow light-emitting phosphor was further mixed with 5.0% by weight of In ₂ O _{3 based} on the first yellow light-emitting phosphor to obtain a yellow light-emitting composition of the present invention.

As Comparative Example 3, a conventional yellow light emitting phosphor was prepared by mixing the same yellow light emitting phosphor as in Example 3 with an average particle size of 4 μm and In ₂ O ₃ at 10.0% by weight.

Using 50 g of each of these slow-electron-beam-excited yellow light-emitting compositions, a fluorescent display tube was prepared in the same manner as in Example 1 and the brightness was measured. When the brightness of the tube was 100%, the brightness of the fluorescent display tube mounted with the fluorescent composition of the present invention was 160%.

Example 4 Blue light emitting phosphor (ZnS: Ag, Al) and yellow light emitting phosphor (ZnS: A)
u, Al) and a white light-emitting composition 100 g mixed in a weight ratio of 1: 2.
And using Atron NIn in the same manner as in Example 3,
1.0% by weight of In ₂ O ₃ and SnO ₂ with respect to the white light emitting composition.
A low-electron-beam-excited white light-emitting composition coated with 1% by weight was obtained.

In ₂ O ₃ having an average particle size of 1 μm was mixed with the obtained light emitting composition in an amount of 5.0% by weight with respect to the initial white light emitting composition to obtain a slow electron beam excited white light emitting phosphor of the present invention.

As Comparative Example 4, a white light emitting composition was prepared by mixing 10% by weight of In ₂ O ₃ having an average particle size of 4 μm with the same white light emitting phosphor as in Example 4.

Using 50 g of each of these slow-electron-beam-excited yellow light-emitting compositions, a fluorescent display tube was prepared in the same manner as in Example 1, and the brightness was measured. When the brightness of the tube was 100%, the brightness of the fluorescent display tube mounted with the light emitting composition of the present invention was 155%.

Example 5 100 g of the red light emitting phosphor {(ZnCd) S: Cu, Cl} was added to 50 ml of water and sufficiently stirred.

20 g of an In ₂ (SO ₄ ) ₃ aqueous solution containing 1.0 wt% of In ₂ O ₃ was added to this suspension, and after sufficiently stirring again, the mixture was allowed to stand still at 80 ° C.
Warmed to evaporate the water. The dried phosphor was fired at 500 ° C. to obtain a slow electron beam excited red light emitting phosphor.

As Comparative Example 5, 5.0% by weight of In ₂ O ₃ having an average particle diameter of 4 μm was mixed with the same red light emitting phosphor as in Example 5 to obtain a slow electron beam excited red light emitting phosphor.

Using 50 g of each of these phosphors, a fluorescent display tube was prepared in the same manner as in Example 1 and the brightness was measured. The brightness of the conventional fluorescent display tube mounted with the slow electron beam excited red light emitting composition was 100%. %, The brightness of the fluorescent display tube mounted with the light emitting composition of the present invention was 150%.

Example 6 100 g of the orange light emitting phosphor {(ZnCd) S: Cu, Cl} was added to 50 ml of ethanol and sufficiently stirred. In ₂ O ₃
Was added in terms of content 1.0 wt% of _{In (NO 3) 3 · 3H} 2 O in aqueous solution 20g, was again thoroughly stirred, and left standing warmed to 50 ° C.,
The ethanol and water were evaporated. The phosphor thus dried was also fired at 500 ° C. to obtain an In particle having an average particle size of 1.0 μm.
4.0 wt% of ₂ O ₃ was dry mixed to obtain a slow electron beam excited orange light emitting phosphor according to the present invention.

As Comparative Example 6, 5.0% by weight of In ₂ O ₃ having an average particle size of 4 μm was mixed with the red light emitting phosphor similar to that of Example 6 to obtain a slow electron beam excited orange light emitting phosphor.

Using 50 g of each of these phosphors, a fluorescent display tube was prepared in the same manner as in Example 1 and the brightness was measured. The brightness of the conventional fluorescent display tube mounted with the slow electron beam excited orange light emitting composition was 100%. %, The brightness of the fluorescent display tube mounted with the light emitting composition of the present invention was 165%.

As can be seen from Examples 1 to 6 above, when the light emitting composition of the present invention is used, an excellent fluorescent display tube having higher brightness than the conventional light emitting composition even if it is excited by a slow electron beam of 50V. Is obtained.

[Effects of the Invention] As described above, according to the present invention, by coating the surface of the phosphor with the conductive metal oxide in the form of a homogeneous film or a semi-homogeneous film, the light emission starting voltage is reduced, and the voltage is 1 kV or less, especially 100 V A phosphor having sufficient conductivity and emission brightness can be obtained under the following low-speed electron beam excitation, and the brightness is further improved by further mixing a granular conductive metal oxide.

Further, according to the present invention, it is possible to obtain a luminescent composition exhibiting not only the brightness but also the coating characteristics on the anode plate, the deterioration of the phosphor, and the like, which are equal to or higher than those of the conventional slow electron beam excited phosphor. .

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

[Brief description of drawings]

1 (a), an electron micrograph showing the structure of a luminescent composition particle in which a semi-homogeneous film of a conductive metal oxide is formed on the surface of the luminescent composition according to the present invention, FIG. 1 (b).
Is an electron micrograph showing the structure of the luminescent composition particles in which the conductive metal oxide particles are attached to the non-homogeneous film of the conductive metal oxide in the luminescent composition according to the present invention. FIG. 3 is a graph showing the relationship between the driving voltage and the relative light emission luminance according to the embodiment and the comparative example of the present invention, and FIG. FIG. 4 is a graph showing the relationship between the added amount of the conductive material and the relative brightness according to one example and comparative example of the present invention, and FIG. 5 is a graph showing the relative brightness and the average particle size. It is a graph which shows a relationship.

Claims (4)

[Claims] 1. A slow-electron-beam-excited phosphor whose surface is coated with a conductive metal oxide in the form of a homogeneous film or a semi-homogeneous film, and a granular conductive metal oxide mixed or attached to the phosphor. And a conductive metal oxide in the form of a homogeneous film or a semi-homogeneous film, and a granular conductive metal oxide, which are at least 1 selected from the group consisting of In ₂ O ₃ and SnO _2. The conductive metal oxide in the form of a homogeneous film or a semi-homogeneous film is a conductive metal compound obtained by heating an organic compound of the conductive metal dissolved in an organic solvent by heating, or the conductive metal. A luminescent composition formed by vapor-depositing or sputtering. 2. The phosphor of the general formula ZnS: M ₁ , M ₂ (provided that M
₁ is at least one element selected from the group consisting of Ag, Zn, Cu, Au and Mn, and M ₂ is Al, F, Cl, Br and I
It is at least one element selected from the group consisting of: ) And the general formula (ZnCd) S: M ₁ , M ₂ (M
The luminescent composition according to claim _1, wherein ₁ and M ₂ are at least one selected from the group consisting of the phosphors represented by the above). 3. The luminescent composition according to claim 1, wherein the volume average particle diameter of the granular conductive metal oxide is 0.05 μm or more and 2.0 μm or less. 4. 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 phosphor amount, and the content of the granular conductive metal oxide is the above-mentioned. The luminescent composition according to claim 1, which is 0.5 to 10% by weight of the phosphor.