JP2004083770A - Fluorescent substance having pigment for low-speed electron beam and fluorescent display tube - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluorescent substance having pigment for low-speed electron beams in which color conversion is sufficiently done and contrast under outside light can be improved, and a fluorescent display tube for which the fluorescent substance having the pigment for low-speed electron beams is used. <P>SOLUTION: In the fluorescent substance for the low-speed electron beams in which pigment (6a) is attached on the surface of a fluorescent particle surface, the pigment has <0.1 μm average particle diameter and the surface of the fluorescent substance having the pigment is covered with a transparent electroconductive oxidized film (6b). In the fluorescent display tube emitting light by injecting the low-speed electron beams to a fluorescent layer formed in a vacuum container, the fluorescent substance for the low-speed electron beams is used. <P>COPYRIGHT: (C)2004,JPO

Description

【００２４】
表１および図４に示すように、実施例１は比較例１よりも輝度に優れると共に、発光色度座標より青色側に色変換された。青色顔料を添加しない（ＺｎＯ：Ｚｎ）蛍光体の発光色度座標は（　０．２５、０．４４　）であることから比較例１における青色側への色変換は僅かであったが、実施例１は顕著に青色側に色変換された。また、表１に示すように、実施例２は比較例２よりも輝度に優れると共に、コントラストが向上した。
【００２５】
【発明の効果】
本発明の低速電子線用蛍光体は、粒子表面に顔料が付着してなる低速電子線用蛍光体であって、上記顔料が平均粒子径　０．１μｍ　未満の粒子であり、顔料付着蛍光体の表面が透明導電性酸化膜で被覆されてなるので、輝度、色変換性能およびコントラストに優れる。
【００２６】
本発明の蛍光表示管は、真空容器内に形成された蛍光体層に低速電子線を射突させて発光させる蛍光表示管において、上記蛍光体層を用いるので、輝度およびコントラストに優れ、多色発光が可能となり、表示品位に優れた蛍光表示管が得られる。
【図面の簡単な説明】
【図１】蛍光表示管の断面図である。
【図２】陽極基板の部分拡大断面図である。
【図３】蛍光体の拡大断面図である。
【図４】発光色度座標を示す図である。
【図５】従来の蛍光体の拡大断面図である。
【符号の説明】
１　蛍光表示管
２　ガラス基板
３　配線層
４　絶縁層
５　陽極電極
６　蛍光体層
７　陽極基板
８　グリット
９　陰極
１０　フェースガラス
１１　スペーサガラス[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a phosphor with a pigment for slow electron beams and a fluorescent display tube using the phosphor with a pigment for slow electrons.
[0002]
[Prior art]
For display elements such as audio, home appliances, measuring instruments, and medical equipment that display a predetermined pattern or graphic, backlights, printer heads, various light sources such as light sources for fax machines and copiers, and flat-panel televisions. A fluorescent display tube is frequently used as a self-luminous element. In recent years, with the expanding use of fluorescent display tubes, studies have been made on improving the contrast under external light, chromaticity conversion for obtaining each emission color, and the like. For example, a pigment having a filter function is added to a ZnO: Zn phosphor having a broad emission spectrum to perform color conversion from the blue-green color inherent to the ZnO: Zn phosphor to green, blue, yellow, or the like. I have. In addition, a color light emitting phosphor such as a ZnCdS phosphor is added with a pigment of the same color as the emission color to improve the contrast under external light.
[0003]
Conventionally, as a phosphor with a pigment for a low-speed electron beam containing a pigment, a phosphor in which a blue pigment, CoAl ₃ O _4, is blended with a ZnO: Zn phosphor for the purpose of converting chromaticity to a blue side is used. HirakiAkira No. 58-71982), a phosphor with reduced deterioration in luminance residual ratio after the high-temperature operation by incorporating a neutral pigment by adding melted SiO ₂ is neutral to alkaline pigment (JP 2000-124593 No.) etc. are known.
[0004]
A conventional phosphor with a pigment for a low-speed electron beam will be described with reference to FIG. FIG. 5 is a partially enlarged view of the phosphor layer formed on the anode. Phosphor particles 6 having an average particle diameter of 0.5 to 5 μm, pigment particles 6 a ′ having an average particle diameter of 0.2 to 5 μm, and conductive oxide particles 6 b ′ having an average particle diameter of 0.1 to 0.5 μm are mixed and dispersed. The phosphor layer 7 thus formed is formed on the anode 5.
Since it is necessary for the phosphor layer 7 to quickly release the incident low-speed electron beam to the anode, the incident electrons are charged up when the insulating pigment particles 6a 'having a small particle diameter cover the surface of the phosphor particles 6. As a result, the brightness decreases. For this reason, when a pigment is compounded, pigment particles 6a 'having a relatively large particle size, for example, 0.2 to 5 μm, are mixed with the phosphor particles 6.
[0005]
[Problems to be solved by the invention]
However, when the average particle diameter of the pigment particles is large, there is a problem that the color conversion is not sufficient and the contrast under external light is not improved.
On the other hand, when the average particle diameter of the pigment particles is reduced, there is a problem that the charge-up of incident electrons occurs and the luminance is reduced.
The present invention has been made to address such a problem, and a pigmented phosphor for a low-speed electron beam capable of sufficiently performing color conversion and improving contrast under external light, and the low-speed electron An object of the present invention is to provide a fluorescent display tube using a phosphor with a line pigment.
[0006]
[Means for Solving the Problems]
The low-speed electron beam phosphor of the present invention is a low-speed electron beam phosphor in which a pigment is attached to a particle surface, wherein the pigment is a particle having an average particle diameter of less than 0.1 μm, The surface is covered with a transparent conductive oxide film.
[0007]
The fluorescent display tube according to the present invention is a fluorescent display tube that emits light by projecting a low-speed electron beam onto a phosphor layer formed in a vacuum vessel, wherein the phosphor layer contains the above-described phosphor for a low-speed electron beam. And
[0008]
A pigment having an average particle size of less than 0.1 μm is attached to the surface of the phosphor for low-speed electron beams, and the surface is coated with a transparent conductive oxide film. Can be obtained efficiently. That is, since the pigment is used in combination with the transparent conductive oxide film, a pigment having an average particle diameter of less than 0.1 μm can be used. When the average particle diameter is less than 0.1 μm, the chromaticity conversion amount is large even if the amount of adhesion is small, and the contrast under external light is improved because the amount of adhesion is small.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
As the phosphor that can be used in the present invention, a known phosphor used in a fluorescent display tube that easily emits light by a low-speed electron beam can be used. For example, a (Zn, Cd) S: Ag, Cl phosphor having a (Zn, Cd) S-based host, a (ZnS: Mn, ZnS: Au, Al) phosphor having a ZnS-based host, (Zn, Mg) ) O: Zn phosphor, ZnGa ₂ O ₄ : Mn phosphor, (Zn, Mg) Ga ₂ O ₄ : Mn phosphor, (Zn, Al) Ga ₂ O ₄ : Mn phosphor, ZnSiO ₄ : Mn phosphor , SrTiO ₃ : Pr, Al phosphor, SnO ₂ : Eu phosphor, Y ₂ O ₂ S: Eu phosphor and the like. The average particle size of the phosphor is 0.5 to 5 μm.
[0010]
As the pigment that can be used in the present invention, any pigment that has a filter function, has transparency without causing light scattering, and can withstand the firing temperature at the time of manufacturing the anode substrate can be used. As such a pigment, an inorganic pigment is preferred.
Among the inorganic pigments, the blue pigments include cobalt aluminate (Al ₂ O ₃ —CoO) pigments, ultramarine blue, navy blue, cerulean blue, Kyacock blue and the like, and the red pigments include ferric oxide pigments and ZnO etc. -Fe ₂ O ₃ -Cr ₂ O ₃ is, as the green _pigment, TiO 2 -NiO-CoO-ZnO _{pigment, CoO-Al 2 O 3 -Cr} 2 O 3 -TiO 2 pigment, _Cr 2 _{O 3} Examples thereof include a system pigment.
[0011]
The average particle size of the pigment is preferably smaller than the phosphor particle size. When the phosphor particle size is 0.5 to 5 μm, it is specifically less than 0.1 μm, preferably less than 0.05 μm. When the pigment particle diameter is smaller than the phosphor particle diameter and less than 0.1 μm, the surface of the phosphor particles can be uniformly dispersed and coated.
[0012]
The amount of the pigment is 0.01 to 5% by weight, and preferably 0.1 to 3% by weight, based on the phosphor. When the amount of the pigment is within this range, the chromaticity conversion amount is large, and the contrast under external light is improved.
[0013]
The transparent conductive oxide that can be used in the present invention uses a transparent conductive oxide that can cover the pigment fine particles attached to the phosphor particle surface, has a large chromaticity conversion amount, and can improve the contrast under external light. it can. For example, a simple oxide such as Sn, Ti, Zn, W, In, and Nb, or a composite transparent conductive oxide thereof may be used. Preferably, In ₂ O ₃ , SnO ₂ , ZnO, ITO (indium tin oxide) and the like can be exemplified.
[0014]
The transparent conductive oxide coated on the surface of the phosphor to which the pigment is attached is 0.1 to 10% by weight, preferably 0.5 to 5% by weight, more preferably 1 to 3% by weight based on the whole phosphor. %. If the amount is less than 0.1% by weight, the effect of improving the conductivity is not sufficient. If the amount exceeds 10% by weight, the thickness of the coating layer becomes too large, and the low-speed electron beam does not sufficiently penetrate into the phosphor layer and the luminance is not improved.
[0015]
The attachment of the pigment to the surface of the phosphor particles and the formation of the transparent conductive oxide coating layer on the surface include (1) a step of attaching the pigment to the surface of the phosphor particles, and (2) a step of coating the transparent conductive oxide. Can be performed. Since the pigment is fine particles having a particle size of less than 0.1 μm, the pigment does not peel off from the phosphor particle surface in the step of forming the transparent conductive oxide.
[0016]
(1) Step of attaching pigment to phosphor particle surface:
Pigment particles having a particle size of less than 0.1 μm are suspended in an aqueous or organic solvent to form a sol, and a predetermined amount of a phosphor is added to the pigment-suspended sol and uniformly dispersed.
In order to prevent aggregation of the pigment suspension sol and improve the stability of the sol, it is preferable to add a dispersant such as polyvinyl alcohol or polyethylene glycol to an aqueous or organic solvent.
A predetermined amount of phosphor particles are added to the pigment suspension sol and uniformly dispersed, and then the solvent is dried using a rotary evaporator or the like, whereby the fine pigment is uniformly dispersed and adhered to the phosphor particle surfaces.
[0017]
(2) Transparent conductive oxide coating step:
The coating of the transparent conductive oxide is performed by dispersing the fine pigment-attached phosphor particles in a solution obtained by dissolving an organic metal alcoholate forming the oxide in a solvent or an aqueous solution of a metal salt such as an aqueous solution of tin chloride. It can be formed by drying and firing.
Further, the transparent conductive oxide can also be coated by mixing, printing, drying, and baking a mixture of a printing paste in which an organometallic alcoholate or the like is dissolved and a fine pigment-attached phosphor particle. The organic metal alcoholate is a compound in which hydrogen of a hydroxyl group of an alcohol is replaced with a metal, and any metal alcoholate that can form a conductive oxide layer can be used. Suitable alcoholates include ethylate, methylate and the like.
A binder resin that can stabilize the organometallic alcoholate can be added to the organometallic alcoholate solution. Suitable binder resins are cellulose derivatives such as ethyl cellulose, methyl cellulose, acetate cellulose, carboxymethyl cellulose and the like. Among them, ethyl cellulose is preferable because of its excellent affinity with the organic metal alcoholate.
Examples of the solvent that dissolves the organic metal alcoholate include carbitols such as butyl carbitol and butyl carbitol acetate, and high boiling solvents such as α-terpineol and 2-phenoxyethanol.
[0018]
The fluorescent display tube of the present invention will be described with reference to FIGS. 1 is a sectional view of a fluorescent display tube, FIG. 2 is a partially enlarged sectional view of an anode substrate constituting the fluorescent display tube, and FIG. 3 is a partially enlarged sectional view of phosphor particles.
The fluorescent display tube 1 is formed by providing an anode substrate 7, a grit 8 and a cathode 9 above the anode substrate 7, sealing with a face glass 10 and a spacer glass 11, and vacuuming. The low-speed electron beam generated from the cathode 9 collides with the pigmented phosphor 6 on the anode substrate 7 to emit light.
As shown in FIG. 2, the anode substrate 7 forms the wiring layer 3 on the glass substrate 2 by printing and applying a conductive paste containing silver as a main component or by a thin film method of aluminum. The insulating layer 4 is formed by printing and applying a low-melting frit glass paste over almost the entire surface except for the anode electrode 5 which is electrically connected through the through holes 4a by printing and applying a graphite paste. The pigmented phosphor 6 is applied on the anode electrode 5 by a printing coating method and then fired to obtain an anode substrate 7.
As shown in FIG. 3, the phosphor 6 has the surface of the phosphor particles having the fine pigment particles 6a attached thereto covered with a transparent conductive oxide layer 6b. The transparent conductive oxide layer 6b only needs to cover at least the surface of the fine pigment particles 6a.
[0019]
【Example】
Example 1
Phosphor (ZnO: Zn) particles having an average particle diameter of 3 μm were added to and dispersed in a pigment suspension sol in which a CoO-based blue pigment having an average particle diameter of 0.05 μm was dispersed. Thereafter, the solvent was dried using a rotary evaporator, and the pigment was uniformly attached to the surface of the phosphor particles. The CoO-based blue pigment was blended at 1% by weight with respect to the phosphor. The obtained phosphor particles with a blue pigment are dispersed in an indium tin oxide (ITO) alkoxide solution, and this dispersion is dried and baked in air at a temperature of 500 ° C. to give a surface of the phosphor particles with a blue pigment. A transparent conductive oxide (ITO) was coated. The transparent conductive oxide (ITO) was blended at 2% by weight based on the whole phosphor.
The phosphor with the pigment for low-speed electron beam was dispersed in a mixed solution of α-terpineol and ethyl cellulose to prepare a printing paste. The anode paste 7 shown in FIG. 2 was produced by screen printing using this printing paste and baking at a temperature of 500 ° C., and the fluorescent display tube shown in FIG. 1 was assembled.
The luminance of the obtained fluorescent display tube was measured at an anode voltage of 26 V and a duty of 1/12. Table 1 shows the luminance expressed as a relative ratio when the luminance of Comparative Example 1 is set to 100%.
Further, the emission chromaticity coordinates in the xy chromaticity diagram of the CIE1931XYZ color system were measured. The results are shown in Table 1 and FIG.
[0020]
Comparative Example 1
Phosphor (ZnO: Zn) particles having an average particle size of 3 μm, a CoO-based blue pigment having an average particle size of 1 μm, and conductive oxide (In ₂ O ₃ ) particles having an average particle size of 0.2 μm are sufficiently placed in a mortar. Was mixed. CoO-based blue pigment is 10% by weight of the phosphor, _{an In} 2 _{O 3} particles were compounded 10% by weight relative to the total phosphor.
An anode substrate and a fluorescent display tube were assembled under the same conditions as in Example 1 using the obtained blue pigment-containing phosphor, and the luminance and emission chromaticity coordinates were measured under the same conditions as in Example 1. The results are shown in Table 1 and FIG.
[0021]
Example 2
Red phosphor (ZnCdS: Ag, Cl) particles having an average particle diameter of 5 μm were added to and dispersed in a pigment suspension sol in which an FeO-based red pigment having an average particle diameter of 0.03 μm was dispersed. Thereafter, the solvent was dried using a rotary evaporator, and the pigment was uniformly attached to the surface of the phosphor particles. The FeO-based red pigment was blended at 1% by weight with respect to the phosphor. The obtained red pigmented phosphor particles are dispersed in a zinc alcoholate solution, and this dispersion is dried and fired in air at a temperature of 500 ° C., so that the transparent conductive oxide ( ZnO). The transparent conductive oxide (ZnO) was blended at 4% by weight based on the entire phosphor.
An anode substrate and a fluorescent display tube were assembled using the obtained red pigment-containing phosphor under the same conditions as in Example 1, and the luminance was measured under the same conditions as in Example 1. Further, the contrast was measured by a luminance difference between a lit portion and a non-lit portion under 200 lx. The results are shown in Table 1.
[0022]
Comparative Example 2
A red phosphor (ZnCdS: Ag, Cl) particle having an average particle diameter of 5 μm, a FeO-based red pigment having an average particle diameter of 2 μm, and a conductive oxide (In ₂ O ₃ ) particle having an average particle diameter of 0.2 μm were mortared. Mix well within. FeO based red pigment is 5 wt% of the phosphor, _{an In} 2 _{O 3} particles were compounded 10% by weight relative to the total phosphor.
Using the obtained red pigment-containing phosphor, an anode substrate and a fluorescent display tube were assembled under the same conditions as in Example 2, and the luminance and contrast were measured under the same conditions as in Example 2. Table 1 shows the results.
[0023]
[Table 1]

[0024]
As shown in Table 1 and FIG. 4, Example 1 was superior in luminance to Comparative Example 1 and was color-converted to the blue side from the emission chromaticity coordinates. Although the luminescent chromaticity coordinates of the phosphor (ZnO: Zn) to which the blue pigment was not added were (0.25, 0.44), the color conversion to the blue side in Comparative Example 1 was slight. 1 was remarkably converted to a blue color. Further, as shown in Table 1, Example 2 was superior to Comparative Example 2 in luminance and improved in contrast.
[0025]
【The invention's effect】
The low-speed electron beam phosphor of the present invention is a low-speed electron beam phosphor in which a pigment is attached to a particle surface, wherein the pigment is a particle having an average particle diameter of less than 0.1 μm, Since the surface is covered with the transparent conductive oxide film, it has excellent brightness, color conversion performance and contrast.
[0026]
The fluorescent display tube of the present invention uses the above-described phosphor layer in a fluorescent display tube which emits light by projecting a low-speed electron beam onto a phosphor layer formed in a vacuum vessel. Light emission becomes possible, and a fluorescent display tube having excellent display quality can be obtained.
[Brief description of the drawings]
FIG. 1 is a sectional view of a fluorescent display tube.
FIG. 2 is a partially enlarged cross-sectional view of an anode substrate.
FIG. 3 is an enlarged sectional view of a phosphor.
FIG. 4 is a diagram showing emission chromaticity coordinates.
FIG. 5 is an enlarged sectional view of a conventional phosphor.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Fluorescent display tube 2 Glass substrate 3 Wiring layer 4 Insulating layer 5 Anode electrode 6 Phosphor layer 7 Anode substrate 8 Grit 9 Cathode 10 Face glass 11 Spacer glass

Claims (2)

A phosphor for a low-speed electron beam in which a pigment is attached to a particle surface,
A pigment-containing phosphor for a low-speed electron beam, wherein the pigment is particles having an average particle diameter of less than 0.1 μm, and the surface of the pigment-attached phosphor is coated with a transparent conductive oxide film. A fluorescent display tube for emitting light by projecting a low-speed electron beam onto a phosphor layer formed in a vacuum vessel, wherein the phosphor layer includes the phosphor with a pigment for a low-speed electron beam according to claim 1. Fluorescent display tube.

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