JP2001234161A - Luminous composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a luminous composition which exerts excellent brightness properties without giving deleterious effect on a cathode in a fluorescent display device, or the like, showing an accelerating voltage of around <=2,000 V. SOLUTION: This luminous composition contains a fluorescent substance which emits light when excited with an electron beam and an SnO2-In2O3 composite oxide power.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel light-emitting composition capable of performing display by sufficiently emitting light even when excited by an electron beam of 2000 V or less, and particularly to a light-emitting composition suitable for use in a fluorescent display device. About.

[0002]

2. Description of the Related Art In a fluorescent display device provided with a filament-shaped oxide cathode or a field emission cathode as an electron source, an accelerating voltage in a range of 100 V to 2000 V is taken into consideration in consideration of withstand voltage of an element and cost of a driver to be used. It is considered desirable to do so. Therefore, even if the phosphor is excited by an electron beam of 2000 V or less, sufficient light emission and display can be performed.
That is, it is important that the dependency on the voltage and the current density is good. However, there is no known phosphor that satisfies the above conditions.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a light emitting composition which exhibits excellent luminance characteristics without adversely affecting a cathode even in a fluorescent display device having an acceleration voltage of about 2000 V or less. I have.

[0004]

Means for Solving the Problems The present inventors have conducted various experiments to achieve the above-mentioned object with respect to a phosphor which emits light by excitation of an electron beam. That is, in the case of an existing phosphor that emits light by excitation of an electron beam, it is extremely difficult to achieve the above-described problem when used alone in a display unit of a fluorescent display device having an acceleration voltage of about 2000 V or less.

Specifically, existing phosphors that emit light when excited by an electron beam have a high specific resistance of the phosphor itself. Therefore, when a phosphor film is formed by using such a phosphor alone, a fluorescent display is obtained. If the operation is continued, electrons are accumulated on the surface of the fluorescent film, and there is a tendency that light emission gradually becomes difficult. In addition, a method of mixing and using a conductive material such as In ₂ O _{3 with} such a phosphor is also conceivable. However, since the conductive material such as In ₂ O ₃ has a high powder specific resistance, the degree of their conductivity is limited. A decrease in effective voltage (or apparent current saturation) occurs, and it is difficult to obtain high-luminance light emission under low-speed electron beam excitation.

[0006] The present inventors have found that light is emitted by excitation of an electron beam.
Based on the above recognition of phosphors,
As a result of repeated experiments and considerations,
Acceleration of about 2000V or less for high-resistance phosphors
To maintain good voltage / current characteristics in voltage
Low resistance SnO_Two-In_TwoO_ThreeSuitable for composite oxide powder
The above problems can be solved by mixing
And completed the present invention. That is, the light emitting set of the present invention
The product is a phosphor that emits light when excited by an electron beam and SnO.
_Two-In_TwoO_ThreeIt is characterized by containing a complex oxide powder
And

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The phosphor used in the present invention may be of any type as long as it emits light when excited by an electron beam. Such a phosphor may be Y ₃ (Al, Ga) ₅ O ₁₂ :
_{Tb, Y 3 Al 5 O 12} : Tb, Y 2 SiO 5: Tb , and InBO _3: green-emitting phosphor selected from the group consisting of _{Tb, Y 2 O 3: Eu} , YVO 4: Eu and Gd ₂ O _3:
A red light-emitting phosphor selected from the group consisting of Eu, Y ₂ Si
O ₅ : Ce, CaWO ₄ , (Ca, Mg) SiO ₃ : T
i and a blue light emitting phosphor selected from the group consisting of Zn ₂ SiO ₄ : Ti.

As the SnO ₂ —In ₂ O ₃ -based composite oxide (hereinafter referred to as ITO) powder used in the present invention, a commercially available product may be used as it is, or a known method (for example, tin chloride and indium chloride) may be used. A method in which the acidic aqueous solution in which the substance is dissolved is neutralized with an alkali to co-precipitate tin / indium hydroxide, and the co-precipitate is calcined.

Regarding the ITO powder used in the present invention,
Those having a molar amount of Sn of 1 to 15 mol% based on the total molar amount of In and Sn in TO are preferable for use in the present invention because of their high conductivity. If the amount of Sn in the ITO is out of this range, the resistance of the ITO powder itself becomes relatively high. Therefore, even if a phosphor film is formed using a composition containing such an ITO powder, the resulting phosphor film is obtained. , The resistance of the phosphor film tends to remain high.

The ITO powder used in the present invention is preferably ultrafine particles having an average primary particle diameter of 0.2 μm or less. This is because the average primary particle size of the ITO powder is 0.2μ.
m, light scattering becomes large, and such ITO
This is because, even when a phosphor film is formed using a composition containing a powder, the resulting phosphor film tends to exhibit characteristics of a non-light-emitting substance and prevent emission of light.

The content of the ITO powder in the light emitting composition of the present invention is preferably 1 to 30% by mass based on the total amount of the phosphor and ITO. When the content of the ITO powder is less than 1% by mass, the resistance of the fluorescent film cannot be reduced, and the phosphor does not emit much light under low-speed electron beam excitation.
On the other hand, if the content of ITO is more than 30% by mass, the amount of the phosphor is substantially reduced accordingly, so that the light emission is weak. Therefore, the content of ITO powder is
It is preferably from 1 to 30% by mass based on the total amount of the phosphor and ITO, and more preferably from 2 to 20% by mass from the viewpoint of luminance.

The luminescent composition of the present invention is prepared by adding an ITO powder or a dispersion of ITO which has been atomized to near primary particles in advance to a phosphor which emits light upon excitation of an electron beam, and thoroughly mixed with a mortar, ball mill, mixer or the like. In some cases, addition of nitrified cotton or the like as a dispersing binder is also useful for obtaining a stable luminescent composition.

[0013]

The present invention will be specifically described below based on examples and comparative examples. Example 1 Y ₃ (Al, Ga) ₅ O ₁₂ : Tb having an average particle size of about 5 μm
(Green light emitting phosphor) 95 parts by mass, Sn content is 5 mol% based on the total amount of ITO powder ((In + Sn)) having an average primary particle diameter of 0.1 μm, and specific resistance is 2 × 10 ⁻² Ω · c.
m powder) was sufficiently mixed with a mortar to obtain a luminescent composition.

The obtained luminescent composition was applied to an anode conductor to produce a fluorescent display device. The fluorescent display device was driven at various acceleration voltages, and the emission luminance was obtained as a relative luminance. The relationship between the obtained acceleration voltage and the relative luminance was as shown in FIG. Further, the chromaticity at the time of the emission is shown on the CIE chromaticity diagram as shown in FIG.

Comparative Example 1 Y ₃ (Al, Ga) ₅ O ₁₂ : Tb having an average particle size of about 5 μm
Was applied alone to the anode conductor to produce a fluorescent display device.
The fluorescent display device was driven at various acceleration voltages, and the emission luminance was obtained as a relative luminance. The relationship between the obtained acceleration voltage and the relative luminance was as shown in FIG. Further, the chromaticity at the time of the emission is shown on the CIE chromaticity diagram as shown in FIG.

[0016] Comparative Example 2 ITO powder having an average primary particle size of 0.1μm of In ₂ O ₃
A luminescent composition was obtained according to the same formulation as in Example 1 except that the powder was changed to powder (powder having a specific resistance of 8 × 10 ² Ω · cm). The obtained luminescent composition was applied to an anode conductor to produce a fluorescent display device. The fluorescent display device was driven at various acceleration voltages, and the emission luminance was obtained as a relative luminance. The relationship between the obtained acceleration voltage and the relative luminance was as shown in FIG.

As is apparent from FIG. 1, the luminescent composition of the present invention (Example 1) is composed of Y which is a constituent of the luminescent composition.
_{3 (Al, Ga) 5 O} 12: luminescent composition consisting of Tb alone (Comparative Example 1) acceleration voltage 3 at almost no emission
Even under excitation of a low-speed electron beam of 00 V or less, it emits green light with high luminance. Further, with respect to the light-emitting composition using a conductive material other than the ITO powder (Comparative Example 2), under high-speed electron beam excitation, high-luminance light in the visible light region cannot be effectively extracted. Further, as is apparent from FIG. 2, the light emitting composition of the present invention (Example 1) is composed of Y ₃ (Al, Ga) ₅ O.
₁₂ : Shows the same chromaticity as that of Tb alone (Comparative Example 1), and can be used as a green light-emitting phosphor without any problem.

Example 2 Y ₃ (Al, Ga) ₅ O ₁₂ : Tb having an average particle size of about 5 μm
And an ITO powder having an average primary particle diameter of 0.1 μm ((In
+ Sn) (powder having a Sn content of 5 mol% and a specific resistance of 2 × 10 ⁻² Ω · cm) based on the total amount of
By changing the mixing ratio with the TO powder in the range of 99: 1 to 10:90 and mixing them sufficiently in a mortar, luminescent compositions having different compositions were obtained.

Each of the obtained luminescent compositions was applied to an anode conductor to produce a fluorescent display device. These fluorescent display devices were driven at an anode voltage of 500 V, and the emission luminance was obtained as a relative luminance. The relationship between the mixing ratio of the phosphor and the ITO powder and the relative luminance was as shown in FIG.

Comparative Example 3 An ITO powder was prepared using In ₂ O ₃ having an average primary particle diameter of 0.1 μm.
A luminescent composition was obtained according to the same formulation as in Example 2, except that the powder was changed to powder (powder having a specific resistance of 8 × 10 ² Ω · cm).

Each of the obtained luminescent compositions was applied to an anode conductor to produce a fluorescent display device. These fluorescent display devices were driven at an anode voltage of 500 V, and the emission luminance was obtained as a relative luminance. The relationship between the mixing ratio of the phosphor and the ITO powder and the relative luminance was as shown in FIG.

As is clear from FIG. 3, the luminescent composition of the present invention (Example 2) shows excellent luminous luminance at any mixing ratio, and the mixing ratio of the phosphor to the ITO powder Y ₃ ( _{al, Ga) 5 O 12:} Tb / ITO = 99 / 1~
Effective results were obtained at 70/30, 98/2 to 80/2
Particularly good results are obtained at 0.

Example 3 95 parts by mass of Y ₂ O ₃ : Eu (red light-emitting phosphor) having an average particle size of about 5 μm and IT having an average primary particle size of 0.1 μm
5 parts by mass of O powder (powder having a Sn content of 5 mol% with respect to the total amount of (In + Sn) and a specific resistance of 2 × 10 ⁻² Ω · cm) is sufficiently mixed using a mortar to form a light emitting composition. I got

The obtained luminescent composition was applied to an anode conductor to produce a fluorescent display device. The fluorescent display device was driven at various acceleration voltages, and the emission luminance was obtained as a relative luminance. The relationship between the obtained acceleration voltage and the relative luminance was as shown in FIG. FIG. 6 shows the chromaticity at the time of light emission on the CIE chromaticity diagram.

COMPARATIVE EXAMPLE 4 Y ₂ O ₃ : Eu having an average particle size of about 5 μm was applied alone to an anode conductor to produce a fluorescent display device. The fluorescent display device was driven at various acceleration voltages, and the emission luminance was obtained as a relative luminance. The relationship between the obtained acceleration voltage and the relative luminance was as shown in FIG. FIG. 6 shows the chromaticity at the time of light emission on the CIE chromaticity diagram.

Comparative Example 5 An ITO powder was prepared by using In ₂ O ₃ having an average primary particle diameter of 0.1 μm.
A luminescent composition was obtained according to the same formulation as in Example 3, except that the powder was changed to powder (powder having a specific resistance of 8 × 10 ² Ω · cm). The obtained luminescent composition was applied to an anode conductor to produce a fluorescent display device. The fluorescent display device was driven at various acceleration voltages, and the emission luminance was obtained as a relative luminance. The relationship between the obtained acceleration voltage and the relative luminance was as shown in FIG.

As is apparent from FIG. 5, the light emitting composition of the present invention (Example 3) is a component of the light emitting composition, Y
_The light-emitting composition composed of ₂ O ₃ : Eu alone (Comparative Example 4) shows high-luminance red light even under excitation of a low-speed electron beam at an acceleration voltage of 300 V or less, which hardly emits light. Further, with respect to the light-emitting composition using a conductive material other than the ITO powder (Comparative Example 5), it is not possible to effectively extract high-luminance light in the visible light region under low-speed electron beam excitation.
As is clear from FIG. 6, the luminescent composition of the present invention (Example 3) has the same chromaticity as that of Y ₂ O ₃ : Eu alone (Comparative Example 4), and is a red-emitting phosphor. Can be used without any problem.

Example 4 The Sn content relative to the total amount of Y ₂ O ₃ : Eu (red light emitting phosphor) having an average particle diameter of about 5 μm and ITO powder ((In + Sn)) having an average primary particle diameter of 0.1 μm was determined. 5 mol%, a specific resistance of 2 × 10 ⁻² Ω · cm), and variously changing the mixing ratio of the phosphor and the ITO powder in the range of 99: 1 to 10:90, and mortaring them. Light-emitting compositions having different compositions were obtained by sufficiently mixing the components.

Each of the obtained luminescent compositions was applied to an anode conductor to produce a fluorescent display device. These fluorescent display devices were driven at an anode voltage of 500 V, and the emission luminance was obtained as a relative luminance. The relationship between the mixing ratio of the phosphor and the ITO powder and the relative luminance was as shown in FIG.

Comparative Example 6 An ITO powder was prepared by mixing In ₂ O ₃ having an average primary particle diameter of 0.1 μm.
A luminescent composition was obtained according to the same formulation as in Example 4, except that the powder was changed to powder (powder having a specific resistance of 8 × 10 ² Ω · cm).

Each of the obtained luminescent compositions was applied to an anode conductor to produce a fluorescent display device. These fluorescent display devices were driven at an anode voltage of 500 V, and the emission luminance was obtained as a relative luminance. The relationship between the mixing ratio of the phosphor and the ITO powder and the relative luminance was as shown in FIG.

As is clear from FIG. 8, the luminescent composition of the present invention (Example 4) shows excellent luminous luminance at any mixing ratio, and the mixing ratio of the phosphor to the ITO powder is Y ₂ O. ₃ : Effective results were obtained with Eu / ITO = 99/1 to 70/30, and particularly good results were obtained with 98/2 to 80/20.

Example 5 95 parts by mass of Y ₂ SiO ₅ : Ce (blue light emitting phosphor) having an average particle size of about 5 μm and I having an average primary particle size of 0.1 μm
5 parts by mass of TO powder (powder having a Sn content of 5 mol% with respect to the total amount of (In + Sn) and a specific resistance of 2 × 10 ⁻² Ω · cm) is sufficiently mixed with a mortar to form a light emitting composition. I got

The obtained luminescent composition was applied to an anode conductor to produce a fluorescent display device. The fluorescent display device was driven at various acceleration voltages, and the emission luminance was obtained as a relative luminance. The relationship between the obtained acceleration voltage and the relative luminance was as shown in FIG. Further, the chromaticity at the time of the emission is shown on the CIE chromaticity diagram as shown in FIG.

Comparative Example 7 A fluorescent display device was manufactured by applying Y ₂ SiO ₅ : Ce having an average particle size of about 5 μm alone to an anode conductor. The fluorescent display device was driven at various acceleration voltages, and the emission luminance was obtained as a relative luminance. The relationship between the obtained acceleration voltage and the relative luminance was as shown in FIG. Further, the chromaticity at the time of the emission is shown on the CIE chromaticity diagram as shown in FIG.

Comparative Example 8 An ITO powder was prepared by using In ₂ O ₃ having an average primary particle diameter of 0.1 μm.
A luminescent composition was obtained by the same formulation as in Example 5, except that the powder was changed to powder (powder having a specific resistance of 8 × 10 ² Ω · cm). The obtained luminescent composition was applied to an anode conductor to produce a fluorescent display device. The fluorescent display device was driven at various acceleration voltages, and the emission luminance was obtained as a relative luminance. The relationship between the obtained acceleration voltage and the relative luminance was as shown in FIG.

As is clear from FIG. 9, the luminescent composition of the present invention (Example 5) is composed of Y which is a constituent of the luminescent composition.
₂ SiO _5: Ce consisting solely luminescent composition (Comparative Example 7)
In this case, blue light emission with high luminance is exhibited even under excitation of a low-speed electron beam at an acceleration voltage of 300 V or less, which hardly emits light. Further, with respect to the light-emitting composition using a conductive material other than the ITO powder (Comparative Example 8), under high-speed electron beam excitation, high-luminance light in the visible light region cannot be effectively extracted. Further, as is clear from FIG. 10, the luminescent composition of the present invention (Example 5) has the same chromaticity as that of Y ₂ SiO ₅ : Ce alone (Comparative Example 7), and is a blue light emitting phosphor. Can be used without any problem.

Example 6 The Sn content was based on the total amount of Y ₂ SiO ₅ : Ce (blue light emitting phosphor) having an average particle size of about 5 μm and ITO powder ((In + Sn)) having an average primary particle size of 0.1 μm. 5 mol%, a specific resistance of 2 × 10 ⁻² Ω · cm), and variously changing the mixing ratio of the phosphor and the ITO powder in the range of 99: 1 to 10:90, and mortaring them. Light-emitting compositions having different compositions were obtained by sufficiently mixing the components.

Each of the obtained luminescent compositions was applied to an anode conductor to produce a fluorescent display device. These fluorescent display devices were driven at an anode voltage of 500 V, and the emission luminance was obtained as a relative luminance. The relationship between the mixing ratio of the phosphor and the ITO powder and the relative luminance was as shown in FIG.

COMPARATIVE EXAMPLE 9 ITO powder was converted to In ₂ O ₃ having an average primary particle diameter of 0.1 μm.
A luminescent composition was obtained according to the same formulation as in Example 6, except that the powder was changed to powder (powder having a specific resistance of 8 × 10 ² Ω · cm).

Each of the obtained luminescent compositions was applied to an anode conductor to produce a fluorescent display device. These fluorescent display devices were driven at an anode voltage of 500 V, and the emission luminance was obtained as a relative luminance. The relationship between the mixing ratio of the phosphor and the ITO powder and the relative luminance was as shown in FIG.

As is apparent from FIG. 12, the light emission of the present invention
The composition (Example 6) was excellent in any mixing ratio.
Of the phosphor and ITO powder
Ratio Y _TwoSiO_Five: Ce / ITO = 99/1 to 70/30
Is effective, and 98/2 to 80/20 is particularly good.
Good results have been obtained.

The luminescent composition of the present invention is not necessarily 20
The application is not limited to the electron beam fluorescent display device using the accelerating voltage of 00 V or less, and the device capable of maintaining good luminance characteristics and the stability of the fluorescent film even in a similar device with a higher voltage is described above. Is clearer.

[0044]

The light-emitting composition of the present invention has, for example, several tens of volts.
A novel light-emitting composition capable of performing display by sufficiently emitting light even when excited by an electron beam accelerated by a relatively low voltage of about several KV, and is particularly suitable for use in a fluorescent display device.

[Brief description of the drawings]

FIG. 1 is a graph showing a relationship between an acceleration voltage and a relative luminance for a fluorescent display device using the light emitting compositions of Example 1, Comparative Examples 1 and 2.

FIG. 2 is a CIE chromaticity diagram showing chromaticity when the light emitting compositions of Example 1 and Comparative Example 1 emit light.

FIG. 3 shows phosphors and IT in Example 2 and Comparative Example 3.
4 is a graph showing a relationship between a mixing ratio with O powder or In ₂ O ₃ and relative luminance.

FIG. 4 is a graph showing the relationship between the acceleration voltage and the relative luminance for the fluorescent display devices using the light emitting compositions of Example 3, Comparative Examples 4 and 5;

FIG. 5 is a CIE chromaticity diagram showing chromaticity when the light emitting compositions of Example 3 and Comparative Example 4 emit light.

FIG. 6 shows phosphors and IT in Example 4 and Comparative Example 6.
4 is a graph showing a relationship between a mixing ratio with O powder or In ₂ O ₃ and relative luminance.

FIG. 7 is a graph showing the relationship between the acceleration voltage and the relative luminance for the fluorescent display devices using the light emitting compositions of Example 5, Comparative Examples 7 and 8.

FIG. 8 is a CIE chromaticity diagram showing chromaticity when the luminescent compositions of Example 5 and Comparative Example 7 emit light.

FIG. 9 shows phosphors and IT in Example 6 and Comparative Example 9.
4 is a graph showing a relationship between a mixing ratio with O powder or In ₂ O ₃ and relative luminance.

Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court II (Reference) C09K 11/79 CPR C09K 11/79 CPR 11/80 CPM 11/80 CPM CPP CPP 11/82 CQC 11/82 CQC H01J 29 / 20 H01J 29/20 31/15 31/15 E

Claims (5)

[Claims] A phosphor which emits light when excited by an electron beam;
nO ₂ -In ₂ O ₃ light-emitting composition characterized by containing a composite oxide powder. 2. The method according to claim 1, wherein the phosphor is Y ₃ (Al, Ga) ₅ O ₁₂ : T.
b, Y ₃ Al ₅ O ₁₂ : Tb, Y ₂ SiO ₅ : Tb and I
NbO _3: luminescent composition according to claim 1, wherein the green-emitting phosphor selected from the group consisting of Tb. 3. A phosphor comprising Y ₂ O ₃ : Eu and YVO ₄ : Eu.
And Gd ₂ O _3: luminescent composition according to claim 1, wherein the red emitting phosphor selected from the group consisting of Eu. 4. The phosphor is Y ₂ SiO ₅ : Ce, CaW.
O ₄ , (Ca, Mg) SiO ₃ : Ti and Zn ₂ SiO
₄ : The light emitting composition according to claim 1, which is a blue light emitting phosphor selected from the group consisting of Ti. 5. The SnO ₂ —In ₂ O ₃ -based composite oxide powder has an average primary particle diameter of 0.2 μm or less, and in the composite oxide, the molar amount of Sn is 1 to the total molar amount of In and Sn. The light emitting composition according to any one of claims 1 to 4, wherein the content is from 15 to 15 mol%.