JP2003073667A - Phosphor and phosphor paste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a phosphor, and a phosphor paste of which handleability is improved. SOLUTION: The phosphor contains an activated aluminate of divalent europium and an A1 composition of a surface of the phosphor is not more than 38 at.%. The phosphor paste comprises an organic binder consisting of the phosphor and a cellulose resin as an essential component. Preferably, a stoichiometric formula of the aluminate is MMgAl10 O17 wherein M is selected from the group consisting of at least Ba, Sr and Ca.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phosphor and a phosphor paste having improved handleability during treatment, processing, transportation or storage with a paste.

[0002]

2. Description of the Related Art Phosphors are used in plasma displays, displays using field emission devices (field emission displays), inorganic EL displays and the like.

A plasma display generates a plasma discharge between electrodes for discharge in an internal space provided between a member having a plurality of electrodes for discharge and a member having a phosphor layer. By irradiating the phosphor provided between the partition walls in the discharge space with the ultraviolet rays generated from the gas sealed in the discharge space, fluorescence is emitted and display is performed.

Oxide-based materials are mainly used for phosphors for plasma displays. The phosphor is prepared by weighing and mixing a predetermined amount of raw materials such as carbonates, hydroxides, and oxides, firing them in the air or in a reducing atmosphere, and then performing steps such as bead mill, washing, classification, and drying. It The average particle diameter of the phosphor particles is generally about 0.5 to 5 μm.

For the phosphor layer of the plasma display, a phosphor paste prepared by mixing the phosphor powder prepared as described above and an organic binder is used in a screen printing method, a nozzle coating method, and a photosensitive paste method in which a photosensitive component is added. After applying it to a predetermined cell position, etc., dry, 400-550 ° C
It is formed by firing to some extent.

In these phosphor forming methods, control of the coating thickness and shape is important from the viewpoint of light emission characteristics. When the coating thickness or shape changes, there arises a problem that the difference in brightness or chromaticity greatly differs depending on the produced plasma display, or unevenness in brightness or chromaticity occurs in one plasma display. The coating thickness and shape of the phosphor depend not only on the process conditions of the above-mentioned forming method but also on the viscosity of the phosphor paste and the thixotropy.
The point is how to uniformly disperse the phosphor powder in the organic binder.

If the dispersibility of the phosphor is excessive, in addition to the above problems, the phosphor paste may not be partially applied due to clogging of the screen plate or clogging of nozzle holes. Problems such as a large number of defects and a low yield are likely to occur.

Conventionally, as a method for producing a phosphor paste, a phosphor powder and a polymer (organic binder) previously dissolved in a solvent are three-roll mill, bead mill,
There are methods such as kneading with a sand mill. Further, for the purpose of removing foreign matter mixed in the raw material, fiber waste mixed in the kneading process, metal powder, etc., it may be filtered with, for example, a stainless mesh filter. The filtration filter is appropriately determined according to the opening of the screen plate used and the nozzle hole diameter.

In the phosphor paste thus produced, the dispersion of the phosphor is insufficient, and the characteristics of the phosphor paste such as viscosity and thixotropy change with time are large,
Since it is difficult to produce stably, production efficiency was reduced.

To solve such a problem, for example, in Japanese Unexamined Patent Publication No. 11-61112, a phosphor, a binder resin and an organic solvent are housed in a closed container, and a stirring part of a homogenizer is immersed in this raw material composition. There is disclosed a method in which a phosphor paste is produced by rotating at high speed. Furthermore, JP-A-2000-273449
The publication also discloses a method in which the stirring portion of the homogenizer is coated with a ceramics film to expand the process margin of the number of revolutions and stirring time to further improve the dispersibility. Further, Japanese Patent Laid-Open No. 2000-345091 also discloses a method of adding a dispersant such as an ionic surfactant or a nonionic surfactant to the phosphor paste.

However, even by these means, the characteristic stability of the phosphor paste was still insufficient. In particular, when an aluminate phosphor activated with divalent europium is used for the blue phosphor, the phosphor powder itself may be destroyed by the dispersion method of applying shearing with a homogenizer,
Addition of a dispersant tends to cause a large deterioration in brightness due to firing.

[0012]

In the phosphor and the phosphor paste obtained by the conventional manufacturing method, a high-viscosity region is partially generated in the phosphor paste, which causes the phosphor paste characteristics to change with time. It is considered that it was easy, the filterability of the filter was lowered, and the screen plate was easily clogged and the nozzle holes were clogged.

Therefore, the present invention has been made in view of the above-mentioned problems in the prior art, and an object of the present invention is to prevent the screen plate from being clogged and the nozzle holes from being clogged so that the phosphor can be stably produced. Another object of the present invention is to provide a phosphor paste to provide a display with less variation in defects and emission characteristics.

[0014]

The present invention basically has the following configuration.

That is, according to the present invention, the Al composition of the surface layer is 38a.
It is a phosphor having a divalent europium-activated aluminate characterized by having a content of t% or less.

Further, the present invention is a phosphor paste containing the phosphor and an organic binder as essential components, wherein the organic binder is composed of a cellulosic resin.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be described below.

The phosphor of the present invention is a divalent europium-activated aluminate phosphor having an Al composition of 3 in the surface layer.
It must be 8 at% or less. Preferably 33
It is at% or less, more preferably 29 at% or less. Note that at% has the same meaning as atomic%, that is, mol%. Alternatively, the internal Al composition ratio (that is, the mole fraction)
When 1 is set, it is important that the Al composition ratio of the surface layer is 1.1 or less. It is more preferably 0.96 or less, still more preferably 0.84 or less.

In the above description, the surface layer is ideally the outermost surface, but considering the measurement limit and the like, the depth of 15 n from the outermost surface when the phosphor powder is observed with a transmission electron microscope or the like.
The definition that the region up to m is the surface layer is most practical in the case where the surface layer and the inside have the same starting composition. That is, the average Al composition in this region satisfies the above Al composition conditions. However, depending on the method of manufacturing the phosphor, it may be appropriate to set the region to a depth of 5 nm from the outermost surface, and if surface treatment or the like is performed, the region may be formed to a depth of 1 nm from the outermost surface. It may be accurate to do so. The composition of the lower layer of this surface layer is
The composition may or may not satisfy the l composition.

By setting the Al composition of the phosphor surface layer to 38 at% or less, it is possible to suppress the occurrence of clogging of the screen plate and nozzle holes. Therefore, since the coating process can be carried out stably and continuously, the production efficiency is improved,
Since the frequency of occurrence of defects is reduced, a display with few defects can be manufactured. Furthermore, in the phosphor paste, a region where the composition of the phosphor and the organic binder differ partially (uneven concentration due to improper mixing) is unlikely to occur, and variation in viscosity can be suppressed, so that the phosphor within the display surface can be suppressed. The layer thickness and shape uniformity are also improved, and a high quality display can be provided.

Further, the filtering characteristics of the filter for removing foreign matters such as fiber waste in the paste (filtering time, filter replacement frequency, filter reusability, cleaning of the filter casing, etc.) are also improved. The part where the phosphor paste comes into contact in the process of manufacturing or applying the phosphor paste (for example, a pipe such as a mill when manufacturing the paste, a valve,
(Paste supply pipes, filtration filters, etc. in the coating process)
Foreign matter (for example, a paste composition having a high viscosity centering on fiber waste, a paste composition in which the phosphor powder is more than the average composition of the phosphor paste, etc.) is less likely to adhere. Therefore, also from this point, it is possible to stably supply the phosphor paste and continuously perform the coating process, and thus the production efficiency can be further improved.

Although the detailed mechanism by which such an effect is obtained by designing the Al composition of the phosphor surface layer as described above has not been clarified, it is presumed as follows from the following examination results. That is, it was found that the high-viscosity deposits clogging the screen plate in the prior art differ from the average composition of the phosphor paste. As a result of detailed study, it was revealed that Al on the surface of the phosphor and ethylcellulose resin, which is an organic binder, interact to bond with each other to form a network. Specifically, when such an adhered matter was examined by infrared absorption spectroscopy, it was found that the adhered matter was found to have a characteristic of 850 cm ^−1.
It was found to have an infrared absorption peak in the vicinity, and it was considered that this was because Al was bonded to the ethylcellulose-based resin. That is, it has been clarified that the Al composition on the surface of the phosphor is one of the causes of troubles such as clogging. Moreover, the following surprising facts were revealed. That is, a conventional divalent europium-activated aluminate phosphor is observed with a transmission electron microscope (TEM), and the local composition analysis of the surface layer and the interior of the phosphor is narrowed down to 5 nm by an energy dispersive spectroscopy using an electron beam ( Nano EDS, eg Vacuum G
When HB501) manufactured by enarator was used, it was found that the phosphor, which should have a uniform composition by nature, had A near the surface compared to the inside.
It turned out a surprising fact that the l composition was large. Specifically, the Al composition of the whole phosphor is adjusted to be 35 at% (Ba, Mg, Al, Eu of the phosphor powder after the preparation).
Of the average composition of ICP method and oxygen analysis by inert gas melting-
Although it was analyzed by an infrared absorption method and the Al composition was confirmed to be 35 at%), it was 41 at% in the surface layer. Here, although the ICP analysis can be performed with an accuracy of 0.1%, the analysis accuracy of the nano EDS is inferior to that of the ICP because it is difficult to analyze oxygen, which is a light element. The measured value of EDS ( ⁱⁿ Al _EDS ) is the whole phosphor (the surface layer is slight, so its influence can be ignored and approximated to the internal composition value) by ICP analysis (Al
_ICP ) is adjusted so that the correction value (Al _ICP
/ ^In Al _EDS ), the measured value of nano EDS ( ^ex AlEDS) in the surface layer of the phosphor was corrected to calculate the Al composition of the surface layer ((Al _ICP / ⁱⁿ Al _EDS ) * ^ex Al _EDS ).
The inside is a circle with a radius of 0.5 μm from the center of gravity of the phosphor powder, and the surface layer is 5 nm deep from the outermost surface of the phosphor powder.
Analyzed. The electron beam used for analysis has a diameter of 5
nm.

In addition, depending on the production conditions of the phosphor powder, it is often observed that no clear lattice fringes are observed on the phosphor surface and the phosphor is amorphous (that is, at least a part of the surface layer is amorphous). In this case, an unexpected result was obtained in which the Al composition of the amorphous layer on the surface was more than that of the inside of the phosphor, and specifically, it was 44 at%. As described above, when the cause of such non-uniformity in the surface layer and the inside of the phosphor is supposed to have a uniform composition and crystal structure both inside and outside the surface layer originally, as described below, It was found to be due to the process.

From the above, the Al composition of the phosphor surface layer is adjusted to 38 at% by adjusting the processing steps as described below.
It is possible to make the following, cellulosic resin and Al
It is presumed that the partial high-viscosity region due to the formation of the network becomes difficult to exist, and the effects as described above can be obtained.

In the present invention, Al on the surface layer of the phosphor is
The lower limit of the composition is preferably 10 at% or more (more preferably 20 at% or more). Usually, the surface layer and the inside have the same starting composition, and the preparation of the surface layer composition is due to a modification effect from the outside, so that it is difficult to largely change only the surface layer composition independently of the internal composition. Therefore, if the lower limit value is not reached, not only the surface layer but also the inside of the phosphor is Al.
This is because the composition tends to deviate significantly from the stoichiometric composition, that is, the emission intensity tends to decrease, which is not preferable.

In the phosphor of the present invention, the thickness of the amorphous layer having a composition different from that of the interior of the phosphor is the excitation ultraviolet rays (wavelength 147 nm, 1
72 nm or the like is generally used), it is desirable that the amorphous layer does not absorb the amorphous layer. Therefore, it is preferable that the amorphous layer does not substantially exist or the thickness is as thin as possible.
Specifically, the average thickness is 15 nm or less, more preferably 1
It is 0 nm or less.

The europium composition of the surface layer of the phosphor is
It is preferably more than 0.01 at% and less than 5 at%. More preferably more than 0.1 at% 4a
It is preferably less than t%. This is because when europium is in this range, red emission from trivalent europium other than the blue emission of the divalent europium-activated aluminate is substantially not seen from the amorphous layer of the phosphor surface layer. Is.

The phosphor of the present invention is the above-mentioned divalent europium.
It is an aluminate phosphor with activated aluminum. Where to activate
Generally means to express a specific function (such as fluorescence)
In order to do this, an activator (e.g., divalent europium) is used as the base material mat
By doping lix (aluminate, etc.)
It As the activated form, the activator is the matrix matrix.
There may be a form in which a specific or unspecified atom of is substituted
For example, there is also a form in which the matrix penetrates between the crystal lattices of the matrix.
is there. In the present invention, the divalent europium activated
In the case of a luminate phosphor, the substituted form is generally
Considered to be the target. Activated bivalent europium
As the aluminate phosphor, for example, BaMgAl₁₄
O_{twenty three}: Eu, BaMgAl_TenO₁₇: Eu, BaMg₂A
l₁₄O_{twenty four}: Eu, etc., but the stoichiometric composition formula is
MMgAl_TenO₁₇And M is at least Ba, S
Bivalent europium containing at least one of r and Ca
It is more preferable that the phosphor is an aluminate phosphor activated with um.
Good Where MMgAl _TenO₁₇When written as
Elementary concentrations are represented by the stoichiometric composition as described above for convenience.
However, it also contains a phosphor less than the above stoichiometric composition.
Is also good. In addition, the elements M, Mg and Al are not always
The stoichiometry does not have to be the case, but the composition may increase slightly.
You may decrease it. For example, M is Ba
The stoichiometric composition is BaMgAl_TenO₁₇: Eu
Eu: Ba = 0.05: 0.95
~ 0.2: 0.8, Mg is 0.85-1.00, Al is
It is about 9.5 to 11.0 (that is, Ba_(1-z)Mg_XA
l_YO17: Eu_Z(X = 0.85-1, Y = 9.5-1
1, Z = 0.05 to 0.2), there is no problem. That is,
In the present invention, if within the composition range as described above
For example, stoichiometric composition formula MMgAl_TenO₁₇Meets also
Can be considered as

The phosphor of the present invention may contain a component other than an aluminate as long as there is no problem in the fluorescent property, etc., but it is usually preferable that the phosphor substantially consists of an aluminate. The same applies to the surface layer, but on the surface,
M for the purpose of improving the heat resistance and UV resistance of the phosphor.
In some cases, gO or the like may be coated.

Regarding the red phosphor, for example, Y
₂ O ₃ : Eu, YVO ₄ : Eu, (Y, Gd) BO ₃ : E
u, Y ₂ O ₃ S: Eu, γ-Zn ₃ (PO ₄ ) ₂ : Mn. For the green phosphor, Zn ₂ GeO ₂ : Mn, BaAl ₁₂
O ₁₉ : Mn, Zn ₂ SiO ₄ : Mn, LaPO ₄ : Tb,
ZnS: Cu, Al, Zn ₂ SiO ₄ : Mn, As, (Z
n, Cd) S: Cu, Al, ZnO: Zn, YB
O ₃ : Tb and the like can be mentioned.

The particle size of the phosphor (for example, 50% cumulative particle size D ₅₀ measured by laser diffraction scattering method) is not particularly limited, but preferably 0.5 to 10 μm (more preferably 1 to 6 μm). , And more preferably 2 to 4 μm). If it is less than the lower limit of the numerical range, it becomes difficult to obtain a phosphor having good crystallinity, so that the emission intensity is low, or the decrease in luminance due to firing becomes large, while if it exceeds the upper limit, the pixel of the plasma display produced. In some cases, the luminance unevenness inside becomes large, which is not preferable. Further, the shape is not particularly limited, and preferably plate-like or spherical.

The organic binder used in the phosphor paste needs to be a cellulosic resin. This is because it is easy to maintain the shape after coating in the screen printing method or the nozzle coating method. What is a cellulosic resin?
For example, methyl cellulose, ethyl cellulose, propyl cellulose, hydroxymethyl cellulose, hydroxyl ethyl cellulose, hydroxyl propyl cellulose, hydroxyl ethyl propyl cellulose and the like.
For example, if it is ethyl cellulose, "N10 farm" manufactured by Hercules, "Ethocel" manufactured by Dow Chemicals, etc. can be used. The organic binder preferably contains a solvent, the solvent for dissolving such a cellulosic resin is not particularly limited, it is preferable that the compatibility is as good as possible, for example, benzyl alcohol and terpineol Is. Further, the organic binder may contain a resin other than the cellulosic resin (for example, polymethylmethacrylate (PMMA)). However, in that case, the cellulose-based resin 100
It is preferably 40 parts by weight or less (more preferably 30 parts by weight or less) with respect to parts by weight. When the value exceeds the upper limit of the above numerical range, the thixotropy of the phosphor paste is likely to be lowered, and it becomes difficult to maintain the shape after the phosphor paste is applied, which is not preferable in some cases. In the organic binder,
The solvent is preferably 200 to 100 parts by weight of the cellulosic resin (including other resins in some cases).
It is added in a proportion of 1000 parts by weight (more preferably 300 to 800 parts by weight, further preferably 350 to 700 parts by weight). If the lower limit of the numerical range is not reached, the solvent becomes insufficient and the viscosity of the phosphor paste becomes too high,
On the other hand, coating becomes difficult, while if it exceeds the upper limit, the viscosity becomes too low and the shape after coating becomes difficult to stabilize, which is not preferable in some cases.

The ratio of the phosphor to the cellulosic resin before dissolution (solid content, optionally including other resins) is such that when screen printing or nozzle coating is used,
70 to 95% by weight of phosphor and 5 to 3 of cellulosic resin
It is preferably 0% by weight. More preferably, the phosphor is 80 to 90% by weight and the cellulosic resin is 10 to 20% by weight. When the ratio is less than the lower limit of the phosphor weight ratio in the numerical range, the ratio of the cellulosic resin becomes high, so that the baking residue is likely to remain, while when the upper limit is exceeded, the resin component becomes insufficient and the screen printing method or the nozzle coating method is applied. In some cases, the application becomes difficult, which is not preferable.

A thixotropy-imparting agent may be added, if necessary, from the viewpoint of the stringing of the paste and the shape of the phosphor layer coating. For example, silica fine particles (for example, "380" and "R974" manufactured by Nippon Aerosil).

For the purpose of further improving the dispersibility of the phosphor and suppressing the settling of the phosphor powder after a long time, an organic compound such as an anionic or nonionic surfactant is contained in the phosphor paste. Although it may contain a system dispersant, a higher aliphatic alcohol, a plasticizer (for example, dibutyl phthalate, dioctyl phthalate, polyethylene glycol, glyceric, etc.), the phosphor paste of the present invention is superior to conventional phosphor pastes. Since the dispersibility is good, the addition amount of such a dispersant may be small. Therefore, the residue of the dispersant after firing the phosphor layer and the deterioration in luminance and chromaticity due to firing, which is remarkable in the blue phosphor, are small. They are,
The content of the phosphor powder is preferably 3% by weight or less (more preferably 1% by weight or less).

The method for producing the phosphor used in the phosphor paste of the present invention will be described below. The present invention is a phosphor having an aluminate in which divalent europium is activated, and emits blue light. As a phosphor material, barium compound (barium oxide, barium hydroxide, barium carbonate, etc.), strontium compound (strontium oxide, strontium hydroxide, strontium carbonate, etc.), calcium compound (calcium oxide, calcium hydroxide, calcium carbonate, etc.), A predetermined amount of europium compound (e.g., europium oxide, europium fluoride), magnesium compound (e.g., magnesium oxide, magnesium hydroxide, magnesium carbonate), aluminum compound (e.g., aluminum oxide, aluminum hydroxide), etc. is weighed and the flux ( Barium fluoride, aluminum fluoride, magnesium fluoride, etc.) and the raw material mixture is thoroughly mixed by a ball mill or the like. The obtained mixture was filled in a crucible and was placed in a reducing atmosphere such as nitrogen or hydrogen, preferably at 1400 ° C.
Baking is performed once or more at a temperature of ˜1650 ° C. for 2 to 40 hours. It is preferably fired twice or more. By firing in a reducing atmosphere, europium is reduced from trivalent to divalent. The calcined product is dispersed, washed, dried, and classified to obtain a divalent europium-activated aluminate phosphor.

In the prior art, a dispersing step such as a bead mill is often carried out in order to monodisperse the particles in which the powder particles are fused together after firing of the phosphor into the respective particles.

However, the surface layer of the phosphor after the dispersion step is often amorphized, which is considered to be due to the crystal layer of the surface layer being amorphized in the mechanical contact with the hard ceramics. In fact, when the dispersion time of the bead mill is shortened, the surface layer of the phosphor tends to be difficult to become amorphous. At the time of amorphization, atoms are selectively scraped, and a relatively hard alumina component is likely to remain. That is, the surface layer is relatively
The l composition tends to be high. Therefore, the Al composition of the surface layer is 3
In order to reduce the content to 8 at% or less, it is sufficient to avoid shearing as much as possible with a bead mill after firing the phosphor powder.

Therefore, the phosphor powders are baked so that the phosphor powders are not fused to each other as much as possible, and the dispersion process is omitted as much as possible, or the surface layer whose composition or state is changed by shearing after the dispersion process is used. Are preferably removed with an acid or alkaline solution. The former can be achieved by reducing the amount of a crystal growth accelerator (flux, such as aluminum fluoride) at the time of producing the phosphor powder within a range that does not affect the light emission characteristics. For example, BaMgAl ₁₀ O ₁₇ :
In the case of the Eu phosphor, the amount of aluminum fluoride is preferably 0.1 to 15% by weight based on the phosphor after firing. It is more preferably 1 to 10% by weight. More preferably 2
6% by weight. Similarly, it is preferable that the firing temperature during the production of the phosphor powder is low and the firing time is short as long as the emission characteristics are not affected. For example, in the aforementioned phosphor, 14
00 ° C-1650 ° C, more preferably 1450 ° C-15
The maximum temperature holding time at 50 ° C. is about 2 to 50 hours, more preferably about 5 to 15 hours.

In the latter case, the phosphor whose surface layer has changed after the dispersion step may be chemically etched with an acidic solution such as hydrochloric acid or nitric acid or an alkaline solution such as sodium hydroxide. Etching conditions such as pH and time of the solution can be adjusted as appropriate so as to remove the surface layer changed in the bead mill step, but etching should not be performed to a portion not altered in the bead mill step.

The phosphor prepared as described above is combined with an organic binder to obtain a phosphor paste. The method for producing the phosphor paste is not particularly limited as long as the phosphor powder can be sufficiently dispersed in the resin. For example, the phosphor powder and the organic binder are kneaded by using a disperser such as a three-roll, ball mill, or planetary mixer. be able to. If the final composition of the polymer and solvent in the organic binder is as described above, the phosphor paste can be prepared without problems.
That is, in addition to mixing the organic binder and the phosphor that have been adjusted to a predetermined amount in advance, the organic binder and the phosphor that are less solvent or polymer than the predetermined amount are mixed, and then the remaining solvent or polymer is mixed. add to·
It can be mixed. Among them, it is preferable to mix the organic binder and the phosphor in which the amount of the polymer is less than the predetermined amount, to prepare a slurry in advance, and finally add / mix the remaining polymer and solvent so that the predetermined amount is achieved. .

By using the phosphor or the phosphor paste of the present invention, it is possible to complete a plasma display or a member thereof having excellent emission characteristics.
In addition, the production of them can efficiently reduce the occurrence of defects. These articles substantially have the compositional or structural characteristics of the phosphor described in detail above (there are some changes due to the firing process and the like). less than,
The plasma display, its members, and its manufacturing method will be described in order, but in addition to these, it can be applied to a field emission display, a display such as an inorganic EL, and its manufacturing method.

A method of manufacturing the AC type plasma display having the structure shown in FIG. 1 will be described below, but the structure is not limited to this. That is, electrodes (sustain electrodes, scan electrodes) for display discharge, which are substrates on the display surface side, are formed on the front plate. In the case of an AC plasma display, the transparent dielectric layer of the electrodes and its protection are protected. In many cases, a MgO thin film is formed as the film. Electrodes (address electrodes) for address-selecting cells to be displayed are formed on the back plate. The partition walls and phosphor layers for partitioning the cells may be formed on either or both of the front plate and the back plate, but in many cases they are formed only on the back plate.

(Member Manufacturing Step) First, regarding the member manufacturing step, a method of manufacturing the front plate will be described.

The glass substrate used for the front plate is not particularly limited, but in general, soda lime glass, glass obtained by annealing soda lime glass, or high strain point glass (for example, "PD-200 manufactured by Asahi Glass Co., Ltd."")
Etc. can be used. The size of the glass substrate is not particularly limited, and a glass substrate having a thickness of 1 to 5 mm can be used.

First, a plurality of electrodes for discharging are formed on a glass substrate. As an electrode forming method, for example, a transparent electrode such as tin oxide or ITO is lifted off, a photo-etching method, etc., silver, aluminum, copper, gold, nickel or the like is screen printed or a photolithography method using a photosensitive conductive paste. You may form a pattern by.
Further, a bus electrode may be formed on the transparent electrode for the purpose of forming an electrode having a lower resistance. Here, the transparent dielectric layer may be formed by a screen printing method or the like on the glass substrate on which a plurality of electrodes for discharging are formed. The transparent dielectric material in that case is not particularly limited, but PbO,
A dielectric material containing B ₂ O ₃ , SiO ₂ is applied.

It is also preferable to form a MgO film on a glass substrate on which a plurality of electrodes for discharge are formed for the purpose of protection from ion bombardment due to discharge. As a forming method, an electron beam evaporation method, a plasma evaporation method, an ion beam assisted evaporation method, a reactive sputtering method of a Mg target, an ion beam sputtering method, a CVD method or the like can be applied.

Next, a method of manufacturing the back plate will be described. The glass substrate used for the back plate may be the same as that described in the description of the front plate.

An address electrode layer containing silver, aluminum, copper, gold, nickel, tin oxide, ITO or the like is patterned on a glass substrate by screen printing or a photolithography method using a photosensitive conductive paste. Further, a dielectric layer may be provided on the address electrode layer to stabilize the discharge.

On the glass substrate on which the address electrode layer is formed, partition walls for partitioning cells are formed by a sandblast method, a mold transfer method, a photolithography method or the like. The material of the partition wall and the shape of the partition wall used in the present invention are not particularly limited.

Further, a process of forming a phosphor layer on a glass substrate on which an electrode layer and partition walls are formed at a predetermined cell position using a phosphor paste containing a phosphor and an organic binder as essential components will be described.

The phosphor paste is preferably applied not only by a screen printing method, a nozzle method, an ink jet method, but also by a photosensitive paste method using a paste to which a photosensitive component is added. This is because these methods make it easy to uniformly form a phosphor layer on a large area.

Finally, firing is carried out at a temperature at which the organic binder cellulosic resin is sufficiently debindered. By this step, the cellulosic resin is lost together with the solvent, so that the plasma display or its member to be completed thereafter does not have cellulosic resin. It should be noted that the phosphor has almost no decomposition, alteration (however, there is a slight change in the oxygen composition due to firing), melting, etc., and almost the same characteristics as when contained in the phosphor paste (Al composition of the phosphor surface layer). , Amorphous average thickness, Eu composition, aluminate stoichiometric composition formula, etc.). When BaMgAl ₁₀ O ₁₇ : Eu is used as the blue phosphor, luminance deterioration easily occurs due to firing, so about 500 ° C. or less is preferable.

In this way, the back plate can be manufactured.

(Sealing Step) The step (sealing step) of sealing the front plate and the back plate with the glass frit for sealing will be described.

The glass frit material for sealing used in the present invention is not particularly limited. For example, a composite frit composed of a low melting point glass containing PbO, B ₂ O _{3 and the} like and a ceramic filler, PbO, ZnO, B. _A crystalline frit made of ₂ O ₃ or the like can be preferably used. Each composition can be appropriately selected depending on the coefficient of thermal expansion of the glass substrate used, the maximum processing temperature in the step after sealing, and the like.

As a method of applying the sealing paste at a predetermined position between the front plate and the rear plate, a glass frit for sealing can be made into a paste and applied to either one or both of the rear plate and the front plate. The polymer and solvent used for the paste for sealing are not particularly limited. For example,
As a polymer, polymethylmethacrylate (PMM
Acrylic resins such as A) and α-terpineol as a solvent. As a coating method, for example, a screen printing method, a dispenser method or the like can be used.

Next, the member coated with the sealing paste is fired for the purpose of removing the resin, solvent, etc. in the applied sealing paste. The firing temperature and the holding time can be appropriately selected depending on the resin and solvent used, but it is preferable to hold the temperature for a certain time at the temperature at which the resin is debindered, and then further raise the temperature within the range where the sealing paste does not show fluidity.

Furthermore, the front plate and the rear plate are sealed by bonding the member coated and fired with the sealing paste and the member to be paired with each other, and maintaining the temperature above the softening point of the glass frit for a certain period of time. The sealing temperature and the holding time can be appropriately set depending on the material of the glass frit. The case of debinding the applied sealing frit paste and sealing the front plate and the back plate respectively was described, but after removing the binding frit from the binder, the front plate and the back plate should not be cooled to room temperature in advance. You may arrange | position in a position, it may seal by heating and hold | maintaining to the softening point or more of a glass frit, and you may perform the vacuum exhaust process mentioned later.

(Vacuum Evacuation / Discharge Gas Encapsulation Process) A process of evacuating the sealed insides of the front plate and the back plate and enclosing the discharge gas will be described. The insides of the sealed front and back plates are evacuated, and when the pressure reaches about 10 ^-2 Pa, heating of the sealed front and back plates is started. The heating temperature is not particularly limited as long as the sealing frit does not exhibit fluidity, and is usually 200 when the MgO film is formed on the front plate.
About 380 ° C is preferable. Further, the holding time is not particularly limited, and the holding time becomes longer for a large-sized plasma display, but it is about 10 hours or less even for a 42 inch plasma display.

After performing a predetermined heating while exhausting gas, the front plate and the back plate that have been sealed to near room temperature are cooled while continuing exhausting, and then discharge gas is introduced up to about 67 kPa for sealing. The discharge gas is not particularly limited, and a mixed gas of helium, neon, argon, krypton, and xenon can be used.

Finally, the driving circuit is mounted to complete the plasma display.

[0063]

EXAMPLES The present invention will be specifically described below with reference to examples. However, the present invention is not limited to this. (Measurement method) (1) Composition analysis Ba, Mg, Al, and Eu composition analysis was carried out by melting about 0.1 g of phosphor powder with sodium carbonate and boric acid, heating and dissolving with pure water, and then acidifying with nitric acid. After making the volume constant with pure water and diluting this solution with dilute nitric acid, a sequential ICP emission spectrometer (SP) manufactured by Seiko Instruments Inc.
S4000) was used to determine the content of each element and calculate the relative value. The composition obtained in this analysis is the average composition of the phosphor powder. Oxygen was analyzed by the inert gas melting-infrared absorption method. (2) Composition analysis of surface layer A sample for a transmission electron microscope (TEM) was prepared by a focused ion beam (FIB), and composition analysis of Al, Eu, etc. in a minute region was performed using energy dispersive spectroscopy (nano). EDS, Vacuum Generator HB50
1). The electron beam diameter used for the measurement is 5 nm. The measurement was carried out at 5 points on each of the inside and the surface layer. The inside is inside a circle with a radius of 0.5 μm from the center of gravity of the phosphor powder, and the surface layer is a depth of 5 from the outermost surface of the phosphor powder.
nm was analyzed. This method does not allow easy analysis of oxygen, which is a light element, with high precision, so nano-ED
Average of 5 internal Al compositions by S analysis ( ⁱⁿ Al _EDS )
Was corrected to match the Al composition (Al _ICP ) calculated from the above ICP analysis value and oxygen analysis value, and the corrected value and the average value of the Al composition of the surface layer by nano EDS analysis ( ^ex Al _EDS ) Then, the corrected surface layer Al composition ((Al _ICP / ⁱⁿ Al _EDS ) * ^ex Al _EDS ) was calculated.
(Al composition obtained by nano EDS tends to be smaller than that obtained by ICP by about 1 to 3%) (3) Thickness measurement of amorphous layer The sample for TEM is a phosphor with a high resolution transmission electron microscope of 200 kV. A lattice image near the surface layer was observed. When no clear lattice fringe was observed, it was determined to be an amorphous layer. (4) Filter Filtration Characteristics Using a stainless steel mesh (# 500, 10 mmφ), the phosphor paste was filtered and filtered until the paste was no longer discharged from the mesh, and the cumulative amount of the paste at that time was measured. In the case of Comparative Example 1 described later, the filtration amount is 10
It was set to 0. (5) Continuous application characteristics of paste (5a) Printing method The phosphor paste was applied to the glass substrate 150 times by the screen printing method, and the screen plate after printing was observed with a 300 times digital microscope, and the mesh part of the screen plate was printed. It was examined whether or not a foreign substance having a high viscosity different from that of the phosphor paste was attached to. (5b) Nozzle coating method After continuously discharging 1 kg of the phosphor paste from a nozzle provided with 20 holes of 150 μmφ, it was examined whether or not foreign matter was attached to the inside of the nozzle hole and its vicinity.

The judgment criteria of the above-mentioned evaluation methods (5a) and (5b) in the continuous coating characteristics of the paste are as follows. That is, after performing the evaluation method of (5a) or (5b), if a high-viscosity foreign substance (excluding fiber scraps) adheres to one or more places of the screen plate opening or the nozzle hole and is completely blocked. Is "x", and when about 50% is attached at each opening and each hole is "△",
The case where there was almost no adhesion was judged as “◯”.

In the following Examples 1 to 10 and Comparative Examples 1 to 7, the handling properties (filterability and continuous coating properties) during processing and treatment of the phosphor paste were evaluated.

(Example 1) Raw materials of barium carbonate, europium oxide, basic magnesium carbonate hydrate and γ-alumina were weighed according to the composition, and aluminum fluoride as a flux was mixed with the phosphor after firing 3 times. % Weight was added and mixed well with a ball mill. After that, nitrogen / hydrogen (95%
/ 5%) In the reducing atmosphere, the maximum temperature was 1430 ° C. and the primary firing was performed for 12 hours including the temperature rise / fall time.
Next, the calcined components were pulverized and classified, and the secondary calcination was performed again under the same conditions as above. Next, bead milling with zirconia ceramics was performed for 1 hour to disperse the phosphor particles after firing. Then, each treatment of classification, washing, and drying is performed, and Ba
A blue phosphor having a composition of _0.9 MgAl ₁₀ O ₁₇ : Eu _0.1 was produced. The Al composition of the surface layer and the inside and the thickness of the amorphous layer were as shown in Table 1.

Next, 80% by weight of the above phosphor powder and 2 parts of ethyl cellulose resin (solid content) as a binder resin are used.
It was set to 0% by weight. As the solvent, benzyl alcohol was used in an amount 5 times that of the ethyl cellulose resin. As the solvent, a solution in which ethyl cellulose was dissolved was prepared in advance, and finally, the phosphor was added, and then the propeller was stirred and kneaded and dispersed with a three-roller to obtain a phosphor paste.

The evaluation results of this phosphor paste are shown in Table 1. Actually, the phosphor paste was applied to the 42-inch rear plate on which the electrodes, the dielectric layer and the partition were formed by the screen printing method. However, the clogging of the screen plate other than the fiber waste, the clogging of the phosphor paste supply port, etc. It did not occur and could be stably and continuously manufactured. The nozzle coating method also enabled stable production.

(Examples 2 to 4, Examples 7, 8 and 10) Example 1 except that the firing temperature, the amount of flux, the bead mill time and the average phosphor composition during the preparation of the phosphor powder were as shown in Table 1. A phosphor powder and a phosphor paste were prepared in the same manner as in.

(Examples 5 and 6) Conditions for producing the phosphor powder are as shown in Table 1. After the phosphor was produced, fluorescence was produced in Example 5 with a dilute nitric acid solution, and in Example 6 with dilute sodium hydroxide. Other than etching the body surface,
A phosphor and a phosphor paste were prepared in the same manner as in Example 1.

Example 9 The conditions for producing the phosphor powder were as shown in Table 1, except that 1% of a nonionic organic compound dispersant was added as a dispersant during the production of the phosphor paste.
A phosphor and a phosphor paste were prepared in the same manner as in Example 1.

Comparative Examples 1 to 6 Phosphors and phosphor pastes were prepared in the same manner as in Example 1 except that the conditions for preparing the phosphor powder were as shown in Table 1.

Comparative Example 7 A phosphor and a phosphor paste were prepared in the same manner as in Example 9 except that the conditions for preparing the phosphor powder were as shown in Table 1.

Table 1 shows Al compositions in the surface layers and inside of Examples 1 to 10 and Comparative Examples 1 to 7, evaluation results of filter filtration characteristics, and results of continuous coating characteristics.

[0075]

[Table 1]

From the results shown in Table 1, it can be seen that Examples 1 to 10 have better filter filtration properties than Comparative Examples 1 to 7 and can be stably produced by the printing method or the nozzle coating method. Particularly, the first embodiment and the ninth and tenth embodiments are preferable.
On the other hand, in the comparative example, the filterability is poor, and stable paste production is difficult, and clogging is also observed in the printing method and nozzle method, and stable production is difficult.

In Example 11 and Comparative Example 8 below, plasma displays were actually manufactured and evaluated.

(Example 11) First, a front plate was prepared. Asahi Glass "PD200" 42 inch glass substrate,
Using ITO, pitch 1290μm, line width 470μm
Scan electrodes were formed. A bus electrode having an electrode width of 120 μm and a thickness of 3 μm was formed on the substrate by a photosensitive silver paste method. Next, a transparent dielectric glass paste was screen-printed to form a front dielectric with a thickness of 30 μm so as to cover the bus electrodes in the display portion. A 0.5 μm thick magnesium oxide layer was formed as a protective film on the substrate on which the dielectric had been formed by electron beam evaporation to prepare a front plate.

Next, a back plate was prepared. "PD200"
Address electrodes having a width of 200 μm, a thickness of 3 μm, and a pitch of 430 μm were formed on a 42-inch glass substrate by using a photosensitive silver paste. Then, a dielectric layer was formed in a thickness of 20 μm by a screen printing method. Then, a width of 60 μm and a height of 1 are formed by a photolithography method using a photosensitive partition paste.
A 20 μm partition wall was formed. Then, a phosphor layer is formed on the partition wall by using the same phosphor paste as that manufactured in Example 4 using the screen printing method, and the partition wall bottom portion and the side wall portion each have a thickness of about 20 μm.
It was formed so as to be m. The red and green phosphor pastes are phosphor powders with red: (Y, Gd, Eu) BO ₃ and green: (Z
An n, Mn) ₂ SiO ₄ composition was used, and one prepared by the same method as the phosphor paste of Example 1 was used. Thus, the back plate was produced. Similarly, the back plate is continuously 300
Although one sheet was produced, it could be stably performed without any problem.

The front plate and the rear plate were aligned so as to enable matrix display drive, and were sealed with a glass frit for sealing, evacuated while heating to 350 ° C., and then Xe5%-
A plasma display was produced by enclosing Ne gas at 67 kPa.

The light emission characteristics of this panel have an initial luminance of 50.
It was 0 cd / m ² , and the in-plane luminance variation was good within 5%.

(Comparative Example 8) A rear plate was prepared as in Example 11 except that the blue phosphor paste used in Comparative Example 4 was used. A back plate was continuously produced as in Example 11, but 1
When 20 sheets were produced, unevenness in the thickness of the phosphor occurred. The cause was that a high-viscosity foreign substance adhered to a part of the screen plate, and the coating amount of the phosphor was changed.

Further, a front plate and a panel were prepared in the same manner as in Example 11. Regarding the emission characteristics of this panel, although the initial luminance was 505 cd / m ² , it was found that the luminance was partially uneven.

[0084]

According to the present invention, it is possible to suppress the occurrence of a screen plate, clogging of nozzle holes and the like, so that it is possible to stably produce a display with few defects and variations in light emission characteristics.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a plasma display for explaining an embodiment of the present invention.

Continued front page    F-term (reference) 3K007 AB11 AB18 DC04 EB00                 4H001 XA08 XA12 XA13 XA20 XA38                       XA56 YA63                 5C036 CC18                 5C040 GG08 JA12 JA13 KB03 KB28                       MA23

Claims (8)

[Claims] 1. A phosphor having a divalent europium-activated aluminate, wherein the Al composition of the surface layer is 38 at% or less. 2. A phosphor having a divalent europium-activated aluminate, wherein an Al composition of a surface layer which is a region from the outermost surface to a depth of 15 nm is 38 at% or less. 3. The average thickness of amorphous on the surface is 1
The phosphor according to claim 1, which has a thickness of 5 nm or less. 4. The europium composition in the surface layer is 0.01a.
The phosphor according to any one of claims 1 to 3, having a content of t% or more and 5 at% or less. 5. The stoichiometric composition formula of the aluminate is MMg.
Al ₁₀ is O _17, and the chemical stoichiometry element M is at least Ba in the composition formula, Sr, and according to any of claims 1 to 3 is made of at least one selected from the group consisting of Ca Phosphor. 6. The phosphor according to claim 5, wherein an activation amount of the divalent europium in the aluminate is 5 to 20 at% with respect to the element M. 7. A phosphor paste containing a phosphor and an organic binder as essential components, wherein the phosphor is the phosphor according to any one of claims 1 to 6, and the organic binder is a cellulosic resin. A phosphor paste characterized by comprising: 8. The phosphor paste according to claim 7, wherein the phosphor is blended at 70 to 95% by weight and the cellulosic resin is blended at a weight ratio of 5 to 30% by weight.