JP2001081459A - Oxide phosphor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an oxide phosphor having high conductivity and being capable of emitting a light of a desired color, which phosphor contains a part that has conductivity and a part that fluoresces when excited by external energy and has a crystalline structure comprising the conductive part and the luminescent part laid upon each other. SOLUTION: This phosphor has a crystalline structure composed of a luminescent part that luminesces upon excitation with external energy and a conductive part that has a conductivity higher than that of the luminescent part and is laid upon the luminescent part. The crystal structure comprises a magnetoplumbite type or a β-alumina type each of which is a structure comprising a spinel block layer and a mirror plane layer which are laid upon each other. The spinel block layer serves as the part having a high conductivity, and the mirror plane layer contains a cation and serves as the luminescent part having the cation as a luminescent center. The phosphor has a composition represented by, for example, the formula: A1-xLnxB1+xGa10-xO17 (wherein A is Ba, Sr, Pb, or the like; Ln is a rare earth element; B is Zn or Mg; and x is 0.01-0.15).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phosphor mainly composed of an oxide containing a rare earth element, and more particularly to a phosphor which can be suitably used for a fluorescent element in a display device such as a fluorescent display tube.

[0002]

2. Description of the Related Art Phosphors that emit light based on energy absorption of light, radiation, etc., use a fluorescent display device (hereinafter referred to as "VFD") having an anode drive voltage of 1 kV or less or a field emission cathode as an electron source. It is used as a fluorescent element (light source) in a display device such as a display device (hereinafter referred to as “FED”). Conventionally, such a display device includes a blue light emitting Zn.
S: Zn (that is, the activator is Zn and the host substance is ZnS
It is. The same applies hereinafter. ), ZnS: Ag, Cl, green-emitting ZnS: Cu, Al, (Zn, Cd) S: Ag, red-emitting (Zn, Cd) S: Ag, Cl, Y ₂ O ₂ S: E
Sulfide phosphors such as u have been frequently used.

However, sulfide phosphors are, for example, V
When used for FD applications, the sulfur component decomposed and separated from the base material by electron beam collision etc. is a cathode (cathode)
And deteriorated the electron emission characteristics, and as a result, the luminance of the phosphor was sometimes reduced. In addition, the use of phosphors containing environmentally unfavorable elements such as Cd has been curtailed due to the increase in environmental problems. Under such circumstances, instead of the sulfide phosphor, green light-emitting ZnGa ₂ O ₄ : Mn, ZnO: Zn or red light-emitting Y ₂
Oxide phosphors, such as O ₃ : Eu and SnO ₂ : Eu, which do not have the drawbacks of the above-mentioned sulfide phosphors, are being used more widely.

[0004]

By the way, the phosphor used for the above-mentioned display device or the like is generally required to have high luminance and to have conductivity. If the brightness is low, satisfactory image display performance is not exhibited, and if the conductivity is low, negative charges tend to be accumulated on the phosphor surface, and as a result, satisfactory light emission is obtained by repelling the irradiated electron beam. Because it is gone.

[0005] However, the above-mentioned conventional oxide phosphors do not always sufficiently satisfy such performance requirements. That is, the above Y ₂ O ₃ : Eu, SnO
₂ : Eu and the like have lower luminance than sulfide phosphors that emit the same color. For this reason, these oxide phosphors cannot be used as substitutes for sulfide phosphors, particularly in VFDs and the like, which are light-emitting devices using a relatively low-speed electron beam having an acceleration voltage of several tens of volts or less. In addition, Y ₂ O ₃ : Eu and the like have a problem of low conductivity (high insulation). That is, if the conductivity is low, negative charges are accumulated on the phosphor surface, and as a result, electron beams are repelled and light emission is inhibited (a so-called charge-up phenomenon). Therefore, in order to obtain the desired conductivity in order to avoid such a charge-up phenomenon, In ₂ must be used.
A relatively large amount of conductive substances such as O ₃ and SnO ₂ must be mixed and used. However, such a conductive substance does not contribute to light emission, but rather has a disadvantage that the light emission level of the phosphor is reduced according to the amount of the conductive substance added. In addition, ZnGa ₂ O ₄ : Mn or Z, which has the above-mentioned performance requirements at a tentative level.
With nO: Zn, red light emission could not be realized.

The present invention has been made to solve the above problems of the conventionally used oxide phosphors.
It is an object of the present invention to provide a new oxide phosphor which has the above performance requirements and can be widely applied to VFD, FED, and the like.

[0007]

The oxide phosphor of the present invention provided to solve the above-mentioned conventional problems has an oxide phosphor having a portion having conductivity and a portion emitting light by energy received from the outside. Object phosphor. Further, the oxide phosphor has a crystal structure in which the conductive portion and the light emitting portion are stacked on each other.

In the oxide phosphor of the present invention having such a structure,
The emission of the electron beam causes the light emitting portion to emit fluorescence, while the charge of the light emitting portion caused by the electron beam irradiation can escape to the outside (for example, a substrate) via the conductive portion. Therefore, according to the oxide phosphor of the present invention, the charge-up phenomenon can be avoided without mixing a large amount of a conductive substance such as In ₂ O ₃ or SnO ₂ .

[0009] Further, a preferable phosphor as the oxide phosphor of the present invention contains a rare earth element in the light emitting portion. When such a rare earth element (typically an ion) is contained, a luminescent color corresponding to the element can be stably obtained.

The preferred oxide phosphor of the present invention have the general _formula: an oxide phosphor represented by _{A 1-X Ln X B 1} + X Ga 10 -X O 17. Here, A in the formula is Ba, S
selected from the group consisting of r, Pb, Ca and La;
n is selected from elements belonging to rare earth elements, and B is Zn or Mg. X in the formula is 0.01 to
It is in the range of 0.15. In another preferred embodiment, the oxide phosphor of the present invention has a general formula: A _1-X Ln _X BGa
An oxide phosphor represented by ₁₁ O ₁₉ . Here, A in the formula is selected from the group consisting of Ba, Sr, Pb, Ca and La, Ln is selected from elements belonging to rare earth elements, and B is Zn or Mg. Also, X in the formula
Is in the range of 0.01 to 0.15.

The oxide phosphor specified by the general formula has high conductivity and can emit light of a desired emission color at a light emitting portion on a surface layer of the phosphor. Therefore, the oxide light-emitting body of this embodiment can be suitably used for a display device such as a VFD.

[0012] Therefore, another aspect of the present invention is to provide a display device comprising any one of the oxide phosphors provided by the present invention as a fluorescent light source. Specifically, such a display according to the present invention includes VF
D, FED, various kinds of cathode ray tubes (CRT), electroluminescent (EL) elements, and the like.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention can be typically implemented as follows.

[0014] The oxide phosphor of the present invention can be excited from outside.
Energy (typically electron beams, ultraviolet rays, X-rays)
A light emitting portion that emits light through
Has a crystal structure in which conductive parts
And limited to some specific compounds
It is not something to be done. Preferred form for such a crystal structure
In the state, the crystal lattice consisting of the light emitting portion and the conductivity
A crystal consisting of a portion that has (ie, a portion through which electrons can easily pass)
There is a laminated structure in which lattices are stacked on each other. Especially preferred
In general, a spinel type structure (spinel block)
It has a crystal structure classified as
Is called magnetoplumbite type or β-alumina type.
It has a crystal structure of Figure 1 for reference
Crystal structure of magnetoplumbite type and β-alumina type
FIG. (A) shows a β-alumina type crystal structure
(B) shows a magnetoplumbite type crystal structure
ing. In this figure, the β-alumina type crystal structure is Ba
²⁺(Large black circle), Ga³⁺And Zn²⁺(small
Black circle) and O ^2-(Open circles). one
On the other hand, the magnetoplumbite crystal structure is La ³⁺(big
Black circle), Ga³⁺And Zn²⁺(Small black circle)
O^2-(Open circles).

As shown in FIG. 1, in both the β-alumina type crystal structure and the magnetoplumbite type crystal structure, a structure in which a layer called a spinel block and a layer called a mirror plane are laminated. It is. Among them, the spinel block layer is a portion having high conductivity and corresponds to the above-mentioned conductive portion. On the other hand, the mirror plane layer has a large cation (Ba ²⁺ , La ³⁺ in the figure)
By replacing such a cation with an element capable of serving as a luminescence center (specific examples will be described later), a phosphor capable of realizing emission of a desired color can be produced. Further, according to such a dense laminated structure including the spinel block layer and the mirror plane layer, the negative charges accumulated in the light emitting portion can be released from any of the conductive portions adjacent to the light emitting portion. Therefore, in the phosphor having the present crystal structure, the light emitting ability in the light emitting portion and the conductive property in the conductive portion can be combined at a high level.

The host substance having such a crystal structure is not particularly limited, but includes zinc (Zn) or magnesium (Mg), gallium (Ga), and oxygen (O) as basic main constituent elements. Is preferable, and barium (Ba), strontium (Sr), and lead (P) are used as cations arranged in the mirror plane layer.
Those containing any ion of b), calcium (Ca) and lanthanum (La) are preferred.

On the other hand, the elements (ions) to be solid-solution-substituted with the cations contained in the base material having the above crystal structure include manganese (Mn), copper (Cu) and the like which can be used as an activator in a conventional phosphor. (I.e., an element that can be a luminescence center), but a rare earth element (ion) is preferable in the practice of the present invention. That is, scandium (Sc), yttrium (Y), lanthanum (La), cerium (Ce), praseodymium (P
r), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (D
y), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb) and lutetium (Lu). In particular, Eu, Ce, Tb, Tm, P
Either r or Dy is suitable as an element (ion) for solid solution substitution with the cation. By subjecting these rare earth elements to solid solution substitution, a phosphor having both high luminance and high conductivity can be obtained.

The phosphor of the present invention has a general formula: A
_{1-X Ln X B 1 +} X Ga 10-X O 1 7 ( hereinafter "Formula 1" hereinafter) oxide phosphor represented by is particularly preferred. Here, A in Formula 1 can be selected from the group consisting of Ba, Sr, Pb, Ca and La. In particular, when Ba is the above β-
It is preferable for forming an alumina type structure. In the formula 1, Ln can be selected from elements belonging to rare earth elements, but Eu or Tb is preferable. In particular, when Eu is used, red light emission with high luminance, which cannot be achieved by the conventional oxide phosphor, can be realized. B is Zn or Mg
Either of the above gives good results. Further, X in the formula is preferably in the range of 0.01 to 0.15 in order to achieve both good formation of the crystal structure and appropriate emission intensity. When Ln is Eu, X is more preferably in the range of 0.05 to 0.1. On the other hand, when Ln is T
In the case of b, X is more preferably in the range of 0.1 to 0.15.

Alternatively, as the phosphor of the present invention, an oxide phosphor represented by the general formula: A _1-X Ln _X BGa ₁₁ O ₁₉ (hereinafter referred to as “formula 2”) is particularly preferable. Here, A in Formula 2 can be selected from the group consisting of Ba, Sr, Pb, Ca and La. Particularly, La is preferable in forming the magnetoplumbite type structure. Further, in the formula 2, Ln can be selected from elements belonging to rare earth elements, but Eu or Tb is preferable. In particular, when Eu is used, red light emission with high luminance, which cannot be achieved by the conventional oxide phosphor, can be realized. B is Zn or Mg
Either of the above gives good results. Further, X in the formula is preferably in the range of 0.01 to 0.15 in order to achieve both good formation of the crystal structure and appropriate emission intensity. When Ln is Eu, X is more preferably in the range of 0.05 to 0.1. On the other hand, when Ln is T
In the case of b, X is more preferably in the range of 0.1 to 0.15.

Next, the method for producing the phosphor of the present invention will be described.
explain. The phosphor of the present invention can be used for ordinary ceramic production.
Mixes various compounds (starting materials) under high temperature conditions
-Obtained by firing. Such starting materials are
Any material that decomposes during firing into an oxide may be used.
It need not be an oxide at the raw material stage. Therefore, departure
As raw materials, in addition to the original oxides, various hydroxides and charcoal
Acid salts, nitrates, organic acid salts and the like may be utilized. Thus,
These are mixed so as to have a predetermined ratio, and are inert in the air.
Predetermined temperature range in neutral atmosphere or reducing atmosphere
Then, the phosphor of the present invention is obtained. Figure
2, a compound included in the formula 1: Ba_0.92Ln
_0.08B_1.08Ga _9.92O₁₇Was a specific example
1 shows a typical method for producing the phosphor of the present invention. Illustrated
First, the starting material for constructing the parent substance of the present invention
Raw material (Ga₂O₃, ZnO and BaCO₃)
Are mixed at a predetermined ratio. In addition, the desired activation concentration (this
In this case, the content of the element to be solid-solution-substituted is 8%).
Compound (here, Eu₂O₃) And mix. Special
Although not limited to, wet mixing (eg, in an agate mortar)
Mixing by addition of seton) for an appropriate time (for example, 20-30)
Minutes). Therefore, it is not suitable for an alumina crucible or the like.
Put the mixed sample in the heat-resistant container for baking,
The firing is performed at a high temperature of about 1500 ° C. The oxide shown in FIG.
When manufacturing phosphors, set the heating rate to 200 ° C per hour
And a temperature range of 1100 ° C. or around (eg, 105
(0 to 1150 ° C) for about 10 to 24 hours
It is preferred to do so. After the firing, the furnace is cooled, typically
A powdery product can be obtained. Note that finally
Set of inorganic oxides (ie, phosphor of the present invention) to be used
Depending on the composition ratio, the composition of the starting material as in the examples described later
Changing the ratio as appropriate is a matter of design for a person skilled in the art.

The powdery phosphor of the present invention obtained by the above-described firing procedure or the like can be subjected to various secondary processings in accordance with the use form, similarly to conventional ceramics. For example, when the phosphor of the present invention is used as a fluorescent element of a fluorescent display tube (see FIG. 10) as described in Example 6 described later, a powdery fluorescent material in the form of a thin film or a plate suitable for the mounting shape. Work your body. For example, by processing the phosphor of the present invention into a paste using a vehicle containing an organic binder, applying the phosphor on a glass substrate on which an anode electrode is formed by screen printing, and further removing the organic binder by firing, the present invention is applied. An anode substrate coated with the phosphor of the present invention can be prepared. The phosphor of the present invention can be processed into various forms by performing such secondary processing. As a result, the phosphor is used as a fluorescent element in a VFD, FED, CRT or the like in which a conventional phosphor is used. be able to.

[0022]

The present invention will be described in more detail with reference to the following examples, but it is not intended to limit the present invention to those shown in the examples.

<Production Example> First, one production example of the base material of the phosphor of the present invention will be described. After weighing and mixing BaCO ₃ , Ga ₂ O ₃ and ZnO at a predetermined ratio, the mixture is placed in an alumina crucible and placed in air at 1300 to 1500 ° C. for 10 minutes.
The firing was performed for ２４24 hours. As a result, BaZnGa
A powdered inorganic compound having a raw material composition ratio corresponding to _{10 17} was obtained. In addition, the result of the powder X-ray diffraction revealed that the obtained inorganic compound was substantially a single-phase pure substance. In the upper part of FIG.
3 shows a powder X-ray diffraction pattern (XRD pattern) of the inorganic compound obtained by firing for a long time. The numerical value on the horizontal axis in the figure is 2θ / deg., And the vertical axis shows the diffraction intensity. A peak suggesting BaGa ₂ O ₄ as an impurity is observed in the figure, but such an impurity peak disappeared by further extending the firing time. The peak (KGa
_The same peak as ₁₁ O ₁₇ ) was identified as belonging to the β-alumina type structure by comparison with the crystal structure simulation result (by the Rietveld method). As shown in FIG. 1 above, the β-alumina type structure (FIG. 1A) similar to the magnetoplumbite type structure (FIG. 1B) has a structure in which a spinel layer and a mirror plane layer are stacked. However, the number and arrangement of atoms in the mirror plane layer differ greatly from the magnetoplumbite structure.
The result is reflected in the magnitude of the lattice constant in the C-axis direction (see FIG. 1). Stevels and Schrama-de Pauw (Journal
According to the Electrochemistry Society, Vol. 123, p. 691 (1976)), if the (c / a) axis ratio of the lattice constant is 3.98 or more, β
-It is reported that it is generally determined to be an alumina type, but in the present example, this was determined by simulation using the Rietbet method, and a β-alumina type structure was determined.

Similarly, BaCO₃, Ga₂O₃And M
gO to BaMgGa₁₀O₁₇Weigh the composition ratio corresponding to
After mixing, put this in an alumina crucible and air
Medium firing at 1300-1500 ° C for 10-24 hours
Was. As a result, BaMgGa ₁₀O₁₇The equivalent of
A powdered inorganic compound having a composition ratio of the powder was obtained. Also, powder X
According to the result of the line diffraction, the obtained inorganic compound was almost
It was found to be a single phase pure. Below Figure 3
Obtained by firing at 1500 ° C for 10 hours in air
Powder X-ray diffraction pattern (XRD pattern
). The powder X-ray diffraction pattern shown in FIG.
As described above, the inorganic compound obtained here is also β-aluminum
It was a pure substance consisting of a single phase with a na-type structure. In addition, this product
Each of the powdered compounds obtained in the fabrication examples was subjected to a load of 1000 MPa.
When the conductivity of the sample obtained by molding the disk into a disk was examined
At this time, each shows a specific resistance of 20Ω to 500Ωcm.
Was.

<Comparative Example> SrCO ₃ and Ga ₂ O ₃ were weighed and mixed at a molar ratio of 1: 6, and then placed in an alumina crucible and placed in air at 1300 ° C. for 10 to 10 minutes.
It was baked for 24 hours. The obtained sample (SrGa
The powder X-ray diffraction pattern of ₁₂ O ₁₉ ) is shown in FIG. Vers
tegen, Journal of Solid State Chemistry, Vol. 7, p. 468
(1973), this sample can be identified as a single phase consisting of a magnetoplumbite-type structure. Also, for a mixture of BaCO ₃ and Ga ₂ O ₃ , a single phase having a magnetoplumbite structure could be obtained under similar firing conditions at 1300 ° C. to 1500 ° C. As shown in FIG. 1, the magnetoplumbite-type crystal structure is a crystalline phase in which a spinel layer and a rock salt-type layer called a mirror plane are stacked in comparison with the β-alumina type structure. Regarding the chemical composition of the phases, SrGa ₁₂ O
₁₉ and BaGa ₁₂ O ₁₉ .

<Example 1> Next, an example of the phosphor of the present invention using the inorganic compound obtained in the above production example as a base substance will be described. As in the above production example, BaCO ₃ , Ga ₂ O ₃
After weighing and mixing ZnO and ZnO in a predetermined ratio,
E so that the activation concentration of u ³⁺ is 5% or 30%.
uO ₃ was weighed and mixed. These mixed powders were sufficiently stirred, and in air, at 1100 to 1500 ° C., 24
The firing was performed under the condition of time (see FIG. 2).

Powder X-ray diffraction of the obtained powdered inorganic compound
4 (XRD pattern) are shown in FIG. The lower part of the figure
The pattern is Eu³⁺Is not activated (that is, the parent
Quality only), and the middle pattern in the figure is Eu.
³⁺In the case of an activation concentration of 5%.
The pattern is Eu³⁺With an activation concentration of 30%
You. As shown, Eu³⁺Sample with activation concentration of 5%
(Ba_0.95Eu_0.05Zn_1.05Ga_9.95
O₁₇)), The compound BaZnGa of the above production example
₁₀O₁₇Since it shows the same diffraction pattern as Eu,³⁺But
It was clarified that the solid solution substitution was properly performed. on the other hand,
Eu³⁺A sample having an activation concentration of 30% (Ba_0.7Eu_0.3
Zn_1.3Ga _9.7O₁₇) For single layer
Cannot be obtained, and the impurity phase is Eu.₃Ga₅O₁₂Mixed
(The white circle peak in the upper part of FIG. 4)
reference).

FIG. 5 shows a sample (B) having a Eu ³⁺ activation concentration of 5%.
_{a 0.95 Eu 0.05 Zn 1.0 5 Ga} 9.95 O
₁₇ ) excitation / emission spectrum (excitation wavelength: 278 n)
m). As shown in this figure, in such a sample, Eu
It became clear that red light emission (peak at about 615 nm) attributed to ⁵ D ₀ to ⁷ F _j (j = 1, 2) associated with activation of ³⁺ was realized.

Example 2 La: Zn: Ga is 1: 1:
After weighing and mixing La ₂ O ₃ and Ga ₂ O ₃ as starting materials so as to have a composition ratio of 11 and 1: 2: 9, firing was performed at 1300 to 1500 ° C. in air for 24 hours. On the other hand, in addition to the starting materials having the same composition ratio as above,
Sintering was also performed under the same conditions with respect to the powder obtained by weighing and mixing Eu ₂ O ₃ so that the activation concentration of u ³⁺ was 5% and 30%. FIG. 6 shows a powder X-ray diffraction pattern (XRD pattern) of each sample obtained by sintering when the composition ratio of La: Zn: Ga is 1: 1: 11. The lower pattern in the figure is a case where Eu ³⁺ is not activated (that is, only the base substance), and the middle pattern in the figure is a case where the Eu ³⁺ activation concentration is 5%. The upper pattern in the middle shows the case where the activation concentration of Eu ³⁺ is 30%.

As shown, a sample in which La: Zn: Ga was synthesized at a composition ratio of 1: 1: 11 (ie, E:
u ³⁺ without activation) was obtained as a single phase of LaZnGa ₁₁ O ₁₉ . Further, as compared with the diffraction pattern of the comparative example, this diffraction pattern had a magnetoplumbite structure. In addition, a sample having 5% activation concentration of Eu ³⁺ (La _0.
95 For Eu _0.05 ZnGa ₁₁ O _19), reference is (6 middle and lower shows the same diffraction pattern as the _LaZnGa 11 _{O 1 9),} it can be confirmed that ^{the Eu 3+} is properly activated . However, a sample (La _0.7 Eu _0.3 ZnGa ₁₁ O) having a Eu ³⁺ activation concentration of 30% was used.
₁₉ ), a single layer was not obtained, and it was clarified that Eu ₃ Ga ₅ O ₁₂ was mixed as an impurity phase (see the white circle peak in the upper part of FIG. 6). In addition, the above L
In the case of a: Zn: Ga synthesized at a composition ratio of 1: 2: 9, it was confirmed that ZnGa ₂ O _{4 as} an impurity phase was mixed (not shown).

FIG. 7 shows a sample (L) having a Eu ³⁺ activation concentration of 5%.
excitation of _{a 0.95 Eu 0.05 ZnGa 1 1 O} 19) ·
The emission spectrum (the excitation wavelength is 291 nm) is shown. As shown in this figure, it became clear that red light emission (peak at about 611 nm) was realized in such a sample as in the case shown in FIG. The conductivity of each sample obtained by molding each powdery compound obtained in the present production example into a disk shape under a load of 1000 MPa was 10%.
It showed a specific resistance of Ω to 200 Ωcm.

Example 3 BaCO ₃ , La ₂ O ₃ , Z
After weighing and mixing Eu ₂ O ₃ at a predetermined ratio so that the activation concentration of nO, Ga ₂ O ₃ , and Eu ³⁺ becomes 5%, the mixture is put into an alumina crucible and placed in air in an air crucible.
C, 1200 C, 1300 C, 1400 C and 150
The firing was performed for 24 hours at each temperature condition of 0 ° C. In FIG.
Ba _0.95 Eu _0.05 Z obtained by this example
n _1.06 Ga _9.95 O ₁₇ shows the relationship between the firing temperature and the red light-emitting intensity of the sample (drawing black circles) and _{La 0.95 Eu 0.05 ZnGa 1 1 O} 19 samples (open circles in the figure). Note that Ba _0.95 Eu _0.05 Zn _1.06 Ga
The excitation wavelength for the _9.95 O ₁₇ sample is 279 nm, and the excitation wavelength for the La _0.95 Eu _0.05 ZnGa ₁₁ O ₁₉ sample is 289 nm. As shown, Ba _0.95 Eu _0.05 Zn _1.06 Ga
_9.95 The O _{1 7} sample, 1100 ° C. to 1500
Although a single phase can be obtained at each firing temperature of
When baked at 0 ° C., the emission intensity was highest.

On the other hand, La _0.95 Eu _0.05 ZnGa
_With respect to the ₁₁ O ₁₉ sample, it was found that a part of the starting material remained at 1100 ° C. (not shown), while it melted at 1500 ° C. Further, under the firing temperature conditions of 1200 ° C. to 1400 ° C. at which a single phase was obtained, the difference in emission intensity was extremely small (see FIG. 8).

<Embodiment 4> BaZn shown in the above production example
Ga₁₀O₁₇And LaZnGa shown in Example 2.
₁₁O₁₉By using this as a parent substance,
Eu³⁺A sample in which the activation concentration was changed was synthesized.
FIG.³⁺Of red emission intensity with activation concentration
Indicates the degree of conversion. Note that here, Ba_1-XEu_XZn
_{1 + X}Ga_10-XO₁₇(White circle in (a) in the figure)
Is fired at a temperature of 1100 ° C._1-XZn_XG
a₁₁O₁₉Was fired at a temperature of 1300 ° C.
See Example 3). Also, Ba_1-XEu_XZn_{1 + X}Ga
_10-XO₁₇About 279nm excitation wavelength, monitor
-Performed at a wavelength of 616 nm. La_1-XZn_XGa₁₁
O₁₉About excitation wavelength 289 nm, monitor wavelength 6
The measurement was performed at 11 nm. As a result, as shown in FIG.
_1-XEu_XZn_{1 + X}Ga_10-XO_{1 7}about
When the activation concentration is 5% to 10% (X = 0.05 to 0.10)
Particularly preferred, around 8% was optimal. On the other hand, La
_1-XZn_XGa₁₁O₁₉About 5% activation concentration
-10% (X = 0.05-0.10) is particularly preferable,
About 6% was optimal. Also, Ba_1-XEu_XZn
_{1 + X}Ga_10-XO₁₇If you use
When the active concentration X is 0.15 or more, Eu₃Ga₅O₁₂Is an impurity
Appeared as a phase (not shown). Also, La_1-XZn_X
Ga₁₁O₁₉Is used, the activation concentration X becomes
Eu over 0.1₃Ga₅O₁₂Appears as an impurity phase
(Not shown). From the above results, Ba_1-XEu_XZ
n_{1 + X}Ga_10-XO₁₇And La _1-XZn_XG
a₁₁O₁₉In each case, a suitable emission intensity was obtained.
To achieve this, the activation concentration is 1 to 15% (X = 0.01 to
0.15) is preferable.

Example 5 A phosphor of the present invention using Tb ³⁺ as an activator instead of Eu ³⁺ was produced. That is, B
aCO ₃ , Ga ₂ O ₃ and ZnO are weighed to a predetermined ratio,
Further, in order to use Tb ³⁺ as an activator, Tb ₄ O ₇ is weighed at a predetermined ratio, the powder obtained by mixing them is placed in an alumina crucible, and calcined in air at 1100 ° C. to 1500 ° C. for 24 hours. Was. The obtained sample (Ba _1-X Eu _X Zn
_{1 + X} Ga _10-X O ₁₇ ) was identified as a single phase having a β-alumina type structure from the result of powder X-ray diffraction. BaCO ₃ , La ₂ O ₃ , Ga ₂ O ₃ and ZnO
Is weighed at a predetermined ratio, and further, Tb ₄ O ₇ is weighed at a predetermined ratio in order to use Tb ³⁺ as an activator, and a powder obtained by mixing them is placed in an alumina crucible, and placed in air at 1100 ° C. to 1500 ° C.
The firing was performed at 24 ° C. for 24 hours. The obtained sample (L
a _1-X Tb _X ZnGa ₁₁ O ₁₉ ) was identified as a single phase having a magnetoplumbite structure from the result of powder X-ray diffraction.

Next, in the same manner as in Example 4, the change in green light emission intensity with respect to the activation concentration of Tb ³⁺ was examined for each of the obtained samples. As a result, Tb ³⁺ optimal for green light emission
The activation concentration of each sample was 10 to 15% (X
= 0.10 to 0.15) (not shown).

Embodiment 6 Next, an example in which the phosphor of the present invention obtained in the above embodiment is applied to a VFD will be described. FIG. 10 is a perspective view of the fluorescent display tube 10 according to the present embodiment to which the phosphor of the present invention is applied, with a part thereof being cut away. The present fluorescent display tube 10 is formed in a frame shape with a substrate 12 made of a green material such as glass, ceramics, or enamel having a plurality of phosphor layers 20S, 20D, and 20N formed in a predetermined light emitting pattern. Glass spacer 1
4, a transparent cover glass plate 16, a plurality of anode terminals 18P, a plurality of grid terminals 18G, a cathode 18
K and an auxiliary grid terminal 18SG.
Thus, the substrate 12, the spacer 14, and the cover glass plate 16 are sealed with glass to form an airtight container, and a vacuum space surrounded by these members is formed therein. .

On the other hand, on the display surface 19 of the fluorescent display tube 10 covered by the vacuum space of the substrate 12, a plurality of phosphor layers 20S representing a character shape of "8" in a segment and one phosphor layer representing a dot shape are provided. A phosphor layer 20D, one phosphor layer 20N forming a “1” character shape, and the like are arranged. Each of the phosphor layers 20S, 20D, 20N is connected to a grid electrode 22.
And the auxiliary grid electrode 24 respectively. The ones of the phosphor layers 20S, 20D, and 20N that are determined in advance for each display digit are connected to the anode terminals 18P via anode printed wirings 34 described later. Each grid electrode 22 is connected to each grid terminal 18G via a grid wiring 26, and each auxiliary grid electrode 24
Indicates each auxiliary grid terminal 1 via the auxiliary grid wiring 28.
8SG.

At both ends of the substrate 12, a pair of filament supporting frames 30 provided with the cathode terminals 18K (only one located on the right side is shown in FIG. 10).
A plurality of thin filaments (filament / cathode) 32 functioning as a directly heated cathode (cathode) are arranged between the filament supporting frames 30 in parallel with the longitudinal direction of the substrate 12. It is stretched so as to be at a predetermined height away from the display surface 19 of the substrate 12. The filament 32 is made of, for example, a tungsten wire or the like whose surface is coated with an oxide solid solution of an alkaline earth metal having a relatively low work function such as (Ba, Sr, Ca) O as an electron emitting layer. It is.

FIG. 11 and FIG. 12, which is a cross-sectional view taken along the line XII-XII, show the structure near the "8" character-shaped phosphor layer 20S, which is one of the display patterns provided on the display surface 19, and its cross section. It is a figure showing a structure. As shown in these drawings, the display surface 19 of the substrate 12 has an anode terminal 1
An anode printed wiring 34 connected to 8P is formed by a thick film screen printing method, a vapor deposition method, or the like. An insulator layer 38 formed at a predetermined thickness and appropriately provided with a through hole 36 penetrating in the thickness direction is fixed thereon. The insulator layer 38 is formed by a thick film screen printing method or the like, and is made of a low-melting glass and a coloring pigment.

On the insulator layer 38, a graphite layer 40 similar to the phosphor layer 20S but having a slightly larger pattern is formed at a position where the graphite layer 40 is electrically connected to the anode printed wiring 34 via the through hole 36. Is formed. This graphite layer 40 functions as an anode of the display tube 10. In this embodiment, the phosphor layers 20S, 2
0D and 20N are formed by printing a thick film phosphor paste on the graphite layer 40, and are configured so that an acceleration voltage is applied through the graphite layer 40. The phosphor layers 20S, 20S
As the D and 20N, the phosphor of the present invention having an emission color such as R (red), G (green), or B (blue) is appropriately selected and used. That is, the phosphor layers 20S, 20D, and 20N can be formed by printing the paste made of the phosphor of the present invention on the graphite layer 40 in a thick film shape.

On the other hand, on the periphery of the phosphor layer 20S, a rib-like wall 44 which is in contact with and surrounds the outer peripheral edge of the phosphor layer 20S is erected from the graphite layer 40 toward the filament 32. Further, the rib-like wall 44 is provided with the green body layer 3.
8 is surrounded by an auxiliary rib-like wall 46 standing upright. These rib-like walls 44 and auxiliary rib-like walls 46
Are made of low-melting-point glass and an inorganic filler such as alumina, etc., have the same height dimensions, and have their upper ends located above the phosphor layer 20S.

The grid electrode 22 and the auxiliary grid electrode 24 are made of particulate graphite, silver, palladium,
A thick-film conductor mainly composed of a particulate conductive material such as copper, aluminum, and nickel, which is provided with a predetermined thickness on top of the rib-shaped wall 44 and the auxiliary rib-shaped wall 46 by a thick-film screen printing method. Have been. The grid electrode 22 and the auxiliary grid electrode 24 are formed by the grid wiring 26 and the auxiliary grid wiring 2 formed on the insulator layer 38.
8 and the grid terminal 18G and the auxiliary grid terminal 18SG are connected to the grid terminal 18G and the auxiliary grid terminal 18SG, respectively, via a grid pad 48 and an auxiliary grid pad 50 formed continuously therefrom.

As shown in FIG. 10, at the left end of the fluorescent display tube 10, that is, at one end in the longitudinal direction, an exhaust pipe 52 made of cylindrical glass is provided. In the manufacturing process of the fluorescent display tube 10, the exhaust pipe 52 serves as the substrate 12, the spacer 14, and the cover glass plate 1 described above.
This is provided for the purpose of evacuating the inside of the hermetic container from the inside after forming an airtight container by sealing the glass 6 with glass, and the distal end thereof is blown off by a gas burner or the like after the end of the evacuation.

When driving the fluorescent display tube 10 configured as described above, an acceleration voltage is sequentially applied to each grid electrode 22 while a predetermined heat current is constantly flowing through the filament 32, and the filament 32 is synchronized with the acceleration voltage. A plurality of phosphor layers 20
An acceleration voltage is applied to any one of S, 20D, and 20N to emit light via the graphite layer 40. Thereby, the thermoelectrons emitted from the filament 32 are accelerated by the grid electrode 22 to which the acceleration voltage is applied. Thus, the phosphor layers 20S, 2 surrounded by the phosphor layers 20S, 2
When an accelerating voltage force is also applied to 0D and 20N, the thermoelectrons collide and the phosphor layers 20S, 20D and 20N emit light. Here, the grid electrode 22 is used as the thermoelectron phosphor layer 20.
S, 20D, and 20N are control electrodes that control arrival to the phosphor layers 20S, 20D, and 20N by eliminating the influence of the negative electric field formed by the surrounding grid electrodes 22. In order to direct thermoelectrons in the same way. The details of such a driving method are not particularly necessary for understanding the phosphor of the present invention, and are well-known and common knowledge of those skilled in the art, and will not be described.

In this embodiment, some of the phosphors of the present invention as manufactured in each of the above embodiments are applied to the phosphor layers 20S, 20D and 20N. That is, in the present embodiment, the graphite layer 40
The above-mentioned phosphor layers 20S, 20 are printed on a thick film of a paste made of the phosphor of the present invention described below.
D, 20N were formed.

In this embodiment, Ba_0.92Eu
_0.08Zn_1.08Ga_9.92O ₁₇, Ba
_0.92Tb_0.08Zn_1.08Ga
_9.92O₁₇, La_{0.9 4}Eu_0.06ZnGa
₁₁O₁₉, BaZn_0.95Mn_0.04Ga₁₀O
₁₇Of the phosphor layers 20S, 20
D, 20N. As a result, the irradiated electron beam
Therefore, Ba_0.92Eu_0.08Zn_{1.0 8}Ga
_9.92O₁₇And La_0.94Eu_0.06ZnG
a₁₁O₁₉Can emit red light with high brightness.
Was. On the other hand, Ba_0.92Tb_0.08Zn _1.08Ga
_9.92O₁₇And BaZn_0.95Mn_0.04G
a₁₀O_{1 7}Can emit high-luminance green light with the two types
Was. Also noticeable charge-up phenomenon is not recognized
Was. Especially Ba_0.92Eu_0.08Zn_1.08Ga
_9.92O₁₇The electron beam emission spectrum shown in FIG.
As is clear from the drawings, the phosphor of the present invention is used
The fluorescent display tube 10 has a characteristic peak at about 615 nm.
And high-intensity bright red light indicating a dark spot was obtained.

[0048]

According to the present invention, there are provided an oxide phosphor having both high luminance and high conductivity and various fluorescent display devices using the phosphor of the present invention as an element. That is,
According to the phosphor of the present invention, the charge-up phenomenon can be avoided without mixing a large amount of a conductive substance such as In ₂ O ₃ or SnO ₂ . Therefore, light emission efficiency with respect to energy supplied for excitation is high, and light emission with high luminance can be realized. Further, it can be suitably used as a fluorescent element derived from an oxide in a fluorescent display device (such as a VFD) using a low-speed electron beam having an acceleration voltage of several tens of volts or less. Further, in the phosphor of the present invention, high-luminance red light emission can be realized by selecting an element serving as a light emission center.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing magnetoplumbite-type and β-alumina-type crystal structures of the phosphor of the present invention.

FIG. 2 is a flowchart showing a manufacturing procedure of the phosphor of the present invention.

FIG. 3 is a graph showing a powder X-ray diffraction pattern (XRD pattern) of the phosphor of the present invention according to an example.

FIG. 4 is a graph showing a powder X-ray diffraction pattern (XRD pattern) of the phosphor of the present invention according to an example.

FIG. 5 shows the excitation and emission of the phosphor of the present invention according to one embodiment.
It is a graph which shows an emission spectrum.

FIG. 6 is a graph showing a powder X-ray diffraction pattern (XRD pattern) of the phosphor of the present invention according to one example.

FIG. 7 shows the excitation and emission of the phosphor of the present invention according to one embodiment.
It is a graph which shows an emission spectrum.

FIG. 8 is a graph showing the relationship between the firing temperature and the luminous intensity in the phosphor of the present invention according to one example.

FIG. 9 shows Eu in the phosphor of the present invention according to one embodiment.
It is a graph which shows the relationship between ³⁺ activation density and red light emission intensity.

FIG. 10 is a partially cutaway perspective view of a fluorescent display tube in one embodiment.

FIG. 11 is a partial plan view showing the vicinity of a phosphor layer in FIG.

12 is a sectional view taken along line XII-XII in FIG.

FIG. 13 is a graph showing an electron beam emission spectrum of the phosphor of the present invention according to one example.

FIG. 14 is a graph showing a powder X-ray diffraction pattern (XRD pattern) of an inorganic compound as one comparative example.

[Explanation of symbols]

 10 fluorescent display tube 20S, 20D, 20N phosphor layer

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Sumito Left Ago No. 3-36, Noritake Shinmachi, Nishi-ku, Nagoya City, Aichi Prefecture Noritake Co., Ltd. Inside (72) Inventor Tadashi Endo 3-2 Ainohara, Iwanuma City, Miyagi Prefecture −23 (72) Inventor Kyota Ueda 1-14-7 Mukaiyama, Tashiro-ku, Sendai City, Miyagi Prefecture Hoyama Apartment A-101 (72) Inventor Takayuki Shimizu 2-20 Aoyama 2-8 Aoyama, Taishiro-ku, Sendai City, Miyagi Prefecture Room 6 F-term (reference) 4H001 XA08 XA12 XA20 XA21 XA30 XA31 XA38 XA39 XA56 XA57 XA58 XA59 XA60 XA61 XA62 XA63 XA64 XA65 XA66 XA67 XA68 XA69 XA70 XA71 XA82 YA61 YA63 YA63 YA66

Claims (5)

[Claims] 1. An oxide phosphor having a crystal structure having a portion having conductivity and a portion emitting light by energy received from the outside, wherein the conductive portion and the light emitting portion are stacked on each other. 2. The oxide phosphor according to claim 1, wherein the crystal structure comprising the conductive portion and the light-emitting portion forms a magnetoplumbite type structure or a β-alumina type structure. 3. The oxide phosphor according to claim 1, which contains a rare earth element. 4. General formula: A_1-XLn_XB_{1 + X}Ga
_10-XO₁₇  The oxide phosphor according to claim 3, which is represented by: Where the expression
A is a group consisting of Ba, Sr, Pb, Ca and La
Ln is selected from the elements belonging to the rare earth elements.
Wherein B is Zn or Mg, wherein X is
It is in the range of 0.01 to 0.15. 5. General formula: A_1-XLn_XBGa₁₁O
₁₉  The oxide phosphor according to claim 3, which is represented by: Where the expression
A is a group consisting of Ba, Sr, Pb, Ca and La
Ln is selected from the elements belonging to the rare earth elements.
Wherein B is Zn or Mg, wherein X is
It is in the range of 0.01 to 0.15.