JP2004091622A - Plasma display panel and fluorophor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluorophor highly resistant to vacuum ultraviolet radiation or ionic impact, and to provide a plasma display panel slight in luminance deterioration during being turned on and having long lifetime. <P>SOLUTION: The fluorophor is such one that an activator is dispersed in a matrix material, wherein the concentration of the activator on the surface of the fluorophor is lower than that inside the fluorophor. Thus, the amount of the activator is less on the surface of the fluorophor subject to main absorption of vacuum ultraviolet radiation, that is, crystal defects are fewer, resulting in realizing the fluorophor highly resistant to vacuum ultraviolet irradiation. By using this fluorophor, the plasma display panel slight in luminance deterioration during being turned on and having long lifetime is realized. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a plasma display panel having a phosphor layer which is used for displaying an image on a television or the like and emits light when excited by vacuum ultraviolet rays.
[0002]
[Prior art]
2. Description of the Related Art In recent years, among color display devices used for image display such as computers and televisions, a plasma display device using a plasma display panel (hereinafter, referred to as a PDP) is a color display device capable of realizing a large, thin, and lightweight. Attention has been paid.
[0003]
The plasma display apparatus performs full-color display by additively mixing so-called three primary colors (red, green, and blue). In order to perform this full color display, the plasma display device is provided with a phosphor layer that emits each of the three primary colors red (R), green (G), and blue (B), and constitutes the phosphor layer. The phosphor is excited by ultraviolet rays generated in the discharge cells of the PDP to generate visible light of each color.
[0004]
Here, as a phosphor constituting the phosphor layer, a material in which an activator is dispersed in a base material as described below is generally used (for example, “Electronic Packaging Technology”, pp. 23-26, 1997). , Vol.13, No.7).
“Blue phosphor”: BaMgAl ₁₀ O ₁₇ : Eu
“Green phosphor”: Zn ₂ SiO ₄ : Mn, BaAl ₁₂ O ₁₉ : Mn, BaMgAl ₁₀ O ₁₇ : Mn, YBO ₃ : Mn
"Red _{phosphor": (Y X Gd 1-X} ) BO 3: Eu
[0005]
[Problems to be solved by the invention]
Conventionally, there has been a problem in PDPs that the luminance is significantly deteriorated with time, that is, the so-called life time is short. This is presumably because the phosphor is damaged and degraded by vacuum ultraviolet rays or ion bombardment generated by the discharge inside the PDP.
[0006]
The present invention has been made in view of such problems, and a phosphor having high resistance to vacuum ultraviolet rays or ion bombardment, and a method of manufacturing the same, and by using the phosphor, luminance degradation is reduced and a long life time is reduced. It is an object to realize a plasma display panel having the following.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a plasma display panel having a phosphor layer which emits light by being excited by ultraviolet light, wherein the phosphor constituting the phosphor layer has an activator dispersed in a base material. Wherein the concentration of the activator on the phosphor surface is smaller than the concentration of the activator inside the phosphor.
[0008]
In order to achieve the above object, the present invention provides a phosphor that disperses an activator in a base material and emits visible light when excited by vacuum ultraviolet rays, and the concentration of the activator on the phosphor surface is reduced. , Characterized in that the concentration is lower than the concentration of the activator inside the phosphor.
[0009]
In addition, in order to achieve the above object, the present invention is characterized in that after mixing and firing the raw material of the base material and the raw material of the activator, the raw material of the base material is further added and mixed and fired. This is a method for producing a phosphor.
[0010]
In order to achieve the above object, the present invention provides a phosphor characterized in that a raw material of a base material and a raw material of an activator are mixed and fired, and the raw material of the base material is further added during the firing. Is a manufacturing method.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
That is, the invention according to claim 1 of the present invention is directed to a plasma display panel having a phosphor layer which emits light by being excited by ultraviolet rays, wherein the phosphor constituting the phosphor layer has an activator dispersed in a base material. Wherein the concentration of the activator on the phosphor surface is smaller than the concentration of the activator inside the phosphor.
[0012]
According to a second aspect of the present invention, in the first aspect, the concentration of the activator increases from the surface of the phosphor toward the inside.
[0013]
According to a third aspect of the present invention, in the first or second aspect of the present invention, the phosphor is formed only of the base material at a depth of 10 nm from the surface.
[0014]
The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the phosphor is a powder having a particle size of 0.1 μm or more and 5 μm or less. It is.
[0015]
The invention according to claim 5 is the invention according to any one of claims 1 to 4, wherein the base material is BaMgAl ₁₀ O ₁₇ and the activator is Eu. is there.
[0016]
The invention according to claim 6 is the invention according to any one of claims 1 to 4, wherein the base material is BaMgAl ₁₀ O ₁₇ and the activator is Mn. is there.
[0017]
The invention according to claim 7 is the invention according to any one of claims 1 to 4, wherein the base material is Zn ₂ SiO ₄ and the activator is Mn. is there.
[0018]
The invention according to claim 8 is the invention according to any one of claims 1 to 4, wherein the base material is BaAl ₁₂ O ₁₉ and the activator is Mn. is there.
[0019]
According to a ninth aspect of the present invention, in the first aspect of the present invention, the base material is YBO ₃ and the activator is Tb.
[0020]
It invention according to claim 10, in the invention of any one of claims 1 to 4, the base material _is a _{(Y X Gd 1-X)} is BO _3, activator Eu It is characterized by the following.
[0021]
According to an eleventh aspect of the present invention, there is provided a plasma display device including a plasma display panel and a driving device for driving the plasma display panel, wherein the plasma display panel is any one of the first to tenth aspects. It is a plasma display panel.
[0022]
The invention according to claim 12 is a phosphor that disperses an activator in a base material and emits visible light when excited by vacuum ultraviolet rays. It is characterized in that the concentration is lower than the concentration of the activator inside the body.
[0023]
According to a thirteenth aspect, in the twelfth aspect, the concentration of the activator increases from the surface to the inside of the phosphor.
[0024]
According to a fourteenth aspect of the present invention, in the twelfth aspect, only the base material is formed at a depth of 10 nm from the surface.
[0025]
According to a fifteenth aspect of the present invention, in any one of the twelfth to fourteenth aspects, the powder has a particle diameter of 0.1 μm or more and 5 μm or less.
[0026]
The invention according to claim 16 is the invention according to any one of claims 12 to 15, wherein the base material is BaMgAl ₁₀ O ₁₇ , and the activator is Eu. is there.
[0027]
The invention according to claim 17 is characterized in that, in the invention according to any of claims 12 to 15, the base material is BaMgAl ₁₀ O ₁₇ and the activator is Mn. is there.
[0028]
The invention according to claim 18 is the invention according to any one of claims 12 to 15, wherein the base material is Zn ₂ SiO ₄ and the activator is Mn. is there.
[0029]
The invention according to claim 19 is the invention according to any one of claims 12 to 15, characterized in that the base material is BaAl ₁₂ O ₁₉ and the activator is Mn. is there.
[0030]
According to a twentieth aspect of the present invention, in any one of the twelfth to fifteenth aspects, the base material is YBO ₃ and the activator is Tb.
[0031]
Further, it is the invention according to claim 21, in the invention of any one of claims 12 15, the matrix material _{is (Y X Gd 1-X)} is BO _3, activator Eu It is characterized by the following.
[0032]
The invention according to claim 22 is characterized in that, after mixing and firing the raw material of the base material and the raw material of the activator, the raw material of the base material is further added and mixed and fired. Is a manufacturing method.
[0033]
According to a twenty-third aspect of the present invention, there is provided a method of manufacturing a phosphor, wherein a raw material of a base material and a raw material of an activator are mixed and fired, and the raw material of the base material is further added during firing. Is the way.
[0034]
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[0035]
FIG. 1 is a perspective view showing a part of a cross section of an image display area of a PDP according to an embodiment of the present invention.
[0036]
The PDP 100 has a front panel on which a display electrode 103, a display scan electrode 104, a dielectric glass layer 105, and an MgO protective layer 106 are disposed on one main surface of a front glass substrate 101, and one main surface of a rear glass substrate 102. And a back panel on which the address electrodes 107, the dielectric glass layer 108, the partition walls 109, and the phosphor layers 110R, 110G, 110B are disposed, and a discharge space 122 formed between the front panel and the back panel. A discharge gas is sealed therein and a discharge cell 123 is formed, and a plasma display device is formed by connecting to a PDP driving device shown in FIG.
[0037]
As shown in FIG. 2, the plasma display device has a display driver circuit 153, a display scan driver circuit 154, and an address driver circuit 155 in the PDP 100, and performs display scan in a discharge cell to be turned on under the control of the controller 152. By applying a voltage to the electrode 104 and the address electrode 107, an address discharge is performed therebetween, and thereafter, a pulse voltage is applied between the display electrode 103 and the display scan electrode 104 to perform a sustain discharge. Due to the sustain discharge, vacuum ultraviolet rays (wavelength: 147 nm) having a short wavelength are generated in the discharge cells, and the phosphor layers (110R, 110G, 110B in FIG. 1) excited by the vacuum ultraviolet rays emit light. Are turned on, and an image is displayed by a combination of lighting and non-lighting of each color discharge cell.
[0038]
Here, the phosphor constituting the phosphor layers 110R, 110G, 110B in the above configuration will be described.
[0039]
3 and 4 show the concentration distribution of the activator (Eu) in the depth direction from the surface to the inside of the phosphor (BaMgAl ₁₀ O ₁₇ : Eu) in one embodiment of the present invention. The phosphor is a powder having a particle diameter of 3 μm, and is a blue light-emitting phosphor BaMgAl ₁₀ O ₁₇ : Eu using BaMgAl ₁₀ O ₁₇ as a base material and Eu as an activator. FIG. 3 is an example in which the activator concentration in the phosphor increases with the depth. FIG. 4 shows an example in which no activator is present up to 10 nm from the surface of the phosphor, and only the base material is used.
[0040]
Here, FIG. 5 shows an evaluation result of a change over time in luminance when the phosphor shown in FIG. 3 is continuously irradiated with 146 nm vacuum ultraviolet rays. The vertical axis represents the relative luminance, and the horizontal axis represents the irradiation time (hour) of the vacuum ultraviolet ray. The figure also shows the result of a conventional phosphor in which the activator (Eu) is uniformly dispersed in the phosphor, that is, has a constant concentration distribution in the depth direction from the surface to the inside. . The solid line is the result of the phosphor of the present embodiment, and the broken line is the result of the conventional phosphor.
[0041]
As can be seen from FIG. 5, in the phosphor of the present embodiment in which the activator concentration increases toward the inside of the phosphor, it has been found that the deterioration due to the irradiation with the vacuum ultraviolet rays is significantly improved.
[0042]
This is because, when the activator is doped into the base material, the cause of the degradation of the phosphor due to the irradiation of the vacuum ultraviolet ray is caused by the strain of the crystal structure of the base material around the activator irradiated with the vacuum ultraviolet ray. In the phosphor of the present embodiment, the activator is less on the phosphor surface where vacuum ultraviolet rays are mainly absorbed, that is, crystal defects are reduced. As a result, vacuum ultraviolet irradiation is performed. It is thought that it became stronger against
[0043]
On the other hand, since the excitation of the phosphor by the vacuum ultraviolet ray is mainly performed by the base material, even if the concentration of the activator near the surface decreases, the luminance does not significantly decrease.
[0044]
In addition, it was confirmed that the effect of improving the crystallinity near the phosphor surface as described above can be obtained not only for vacuum ultraviolet irradiation but also for ion bombardment.
[0045]
Further, as shown in FIG. 4, in the phosphor containing no activator within a few tens of nm from the surface, the crystallinity near the phosphor surface is further improved, and the phosphor exhibits higher resistance to vacuum ultraviolet irradiation and ion bombardment. It was confirmed.
[0046]
The above-mentioned effects were remarkably confirmed in the case of a BaMgAl ₁₀ O ₁₇ : Eu phosphor which was relatively weak to the conventional vacuum ultraviolet rays. Weakly BaMgAl ₁₀ O ₁₇ : Mn (base material is BaMgAl ₁₀ O ₁₇ and activator is Mn) or BaAl ₁₂ O ₁₉ : Mn (base material is BaAl ₁₂ O ₁₉ and activator is Mn) In addition, a remarkable effect was similarly confirmed for a phosphor such as Zn ₂ SiO ₄ : Mn (base material is Zn ₂ SiO ₄ and activator is Mn) which is relatively weak to ion bombardment.
[0047]
Furthermore, YBO ₃ : Tb (base material is YBO ₃ and activator is Tb) and (Y _X Gd _{1 -X} ) BO ₃ : Eu (base material is relatively strong against vacuum ultraviolet rays and ion impact) a _{(Y X Gd 1-X)} BO 3, even in the phosphor of the activator is Eu), etc., it was possible to obtain the effect.
[0048]
Although the above effects are not particularly dependent on the particle size of the phosphor, it has been confirmed that the effect is remarkable for a powdered phosphor having a particle size of 0.1 μm or more and 5 μm or less.
[0049]
As described above, according to the present invention, a phosphor having high resistance to vacuum ultraviolet rays or ion bombardment can be realized.
[0050]
Further, since the PDP according to the embodiment of the present invention uses the above-described phosphor, it is possible to realize a plasma display panel having little deterioration in luminance and a long life time. Here, the life time indicates a driving time until the relative relative luminance becomes a predetermined value, and is expressed by, for example, a driving time until the relative luminance decreases to 50%.
[0051]
FIG. 6 shows a temporal change in luminance when blue display is continuously performed on the PDP of the present embodiment. The vertical axis represents the relative luminance of blue, and the horizontal axis represents the display time (hour). Further, in the figure, the brightness of the conventional PDP using the BaMgAl ₁₀ O ₁₇ : Eu phosphor which does not have the activator concentration distribution in the depth direction of the conventional phosphor is shown when the blue display is continued. Changes are also shown. The solid line is the result of the PDP using the phosphor of the present embodiment, and the broken line is the result of the PDP using the conventional phosphor.
[0052]
As can be seen from FIG. 6, it has been confirmed that in the PDP of the present embodiment, the luminance degradation is significantly reduced and the life time is prolonged. Further, as shown in FIG. 4, in a PDP using a phosphor containing no activator up to a depth of 10 nm from the surface, it was confirmed that the luminance deterioration was further improved and the life time was further increased.
[0053]
Similarly, BaMgAl ₁₀ O ₁₇ : Mn (base material is BaMgAl ₁₀ O ₁₇ and activator is Mn), BaAl ₁₂ O ₁₉ : Mn (base material is BaAl ₁₂ O) as a phosphor constituting the green phosphor layer. ₁₉ , the activator is Mn), Zn ₂ SiO ₄ : Mn (the base material is Zn ₂ SiO ₄ and the activator is Mn) or YBO ₃ : Tb (the base material is YBO ₃ , It was confirmed that even when Tb) was used as the agent, the effect of improving the luminance degradation was similarly obtained and the life time was prolonged.
[0054]
The phosphor as _{(Y X Gd 1-X)} BO 3 constituting the red phosphor _layer: (a _{(Y X Gd 1-X)} BO 3 , activator Eu) Eu Even with, Similarly, it was confirmed that an effect of improving the luminance degradation was obtained and the life time was prolonged.
[0055]
In the above embodiment, the surface discharge type PDP is exemplified. However, the present invention can be applied to all PDPs or discharge lamps in which the phosphor is subjected to vacuum ultraviolet irradiation or ion bombardment, such as a facing discharge type PDP.
[0056]
Next, a method for manufacturing the above-described phosphor will be described.
[0057]
First, as a raw material of the base material, barium carbonate (BaCo _3), magnesium carbonate (MgCO _3), aluminum oxide _{(α-Al 2 O 3)} Ba, Mg, so as to be 1: 1: 10 in terms of atomic ratio of Al Mix.
[0058]
Next, a predetermined amount of europium oxide (Eu ₂ O ₃ ) is added to the mixture as a raw material of the activator Eu.
[0059]
Then, if necessary, a suitable amount of flux (AlF ₂ , BaCl ₂ ) is mixed with a ball mill, and the mixture is mixed at 1200 ° C. to 1500 ° C. for a predetermined time (eg, 0.5 hour) in a weak reducing atmosphere (H ₂ , N ₂₎ . B) to synthesize. The synthesized phosphor, further barium carbonate as a raw material of the base material (BaCo _3), magnesium carbonate (MgCO _3), further mixed with aluminum oxide _{(α-Al 2 O 3)} , and again, 1100 ° C. to 1300 By sintering in the air at a predetermined temperature for a predetermined time, the activator (Eu) concentration on the surface of the phosphor (BaMgAl ₁₀ O ₁₇ : Eu) is smaller than the activator (Eu) concentration inside the phosphor. Can be synthesized.
[0060]
Here, the concentration distribution in the depth direction of the activator (Eu) is adjusted by adjusting the temperature and time of the above-described firing performed in the air at 1100 ° C. to 1300 ° C. for a predetermined time. Is possible. For example, the lower and the shorter the refiring temperature, the lower the surface activator (Eu) concentration can be.
[0061]
Further, as another embodiment of the method for producing a phosphor, a method in which a mixture obtained by mixing a raw material of a base material and a raw material of an activator is fired, and the raw material of the base material is further added during the firing, is similar. It was confirmed that a phosphor having a suitable activator (Eu) concentration distribution could be synthesized.
[0062]
【The invention's effect】
As described above, according to the present invention, it is possible to suppress luminance degradation due to vacuum ultraviolet rays or ion bombardment of a phosphor, and as a result, a plasma display panel having a long life time can be realized.
[Brief description of the drawings]
FIG. 1 is a cross-sectional perspective view showing a part of the structure of an image display area of a plasma display panel according to an embodiment of the present invention. FIG. 2 is a plasma display device using the plasma display panel according to an embodiment of the present invention. FIG. 3 is a diagram showing an activator (Eu) concentration distribution in a depth direction in a phosphor according to an embodiment of the present invention. FIG. 4 is a diagram showing a phosphor according to another embodiment of the present invention. FIG. 5 is a diagram showing an activator (Eu) concentration distribution in a depth direction. FIG. 5 shows a time-dependent luminance of a phosphor according to an embodiment of the present invention and a conventional phosphor when irradiation with vacuum ultraviolet rays is continued. FIG. 6 is a diagram showing a comparison of change in luminance over time when a blue display is continuously performed between the plasma display panel according to one embodiment of the present invention and a conventional plasma display panel. Explanation of code]
100 PDP
101 Front glass substrate 102 Back glass substrate 103 Display electrode 104 Display scan electrode 105 Dielectric glass layer 106 MgO protective layer 107 Address electrode 108 Dielectric glass layer 109 Partition 110R Phosphor layer (red)
110G phosphor layer (green)
110B phosphor layer (blue)
122 discharge space

Claims (23)

In a plasma display panel having a phosphor layer that emits light when excited by ultraviolet light, the phosphor constituting the phosphor layer is obtained by dispersing an activator in a base material, A plasma display panel, wherein the concentration is lower than the concentration of the activator inside the phosphor. The plasma display panel according to claim 1, wherein the concentration of the activator increases from the surface of the phosphor toward the inside. The plasma display panel according to claim 1, wherein the phosphor is made of only a base material at a depth of 10 nm from the surface. 4. The plasma display panel according to claim 1, wherein the phosphor is a powder having a particle size of 0.1 μm or more and 5 μm or less. The plasma display panel according to claim 1, wherein the base material is BaMgAl ₁₀ O ₁₇ , and the activator is Eu. The plasma display panel according to claim 1, wherein the base material is BaMgAl ₁₀ O ₁₇ and the activator is Mn. Base material, Zn ₂ a SiO _4, the plasma display panel according to any one of claims 1 to 4, wherein the activator is Mn. Base material _is a _BaAl 12 _{O 19,} a plasma display panel according to any one of claims 1 to 4, wherein the activator is Mn. Base material is a YBO _3, a plasma display panel according to any one of claims 1 to 4, wherein the activator is Tb. Base _{material, (Y X Gd 1-X} ) is BO _3, a plasma display panel according to any one of claims 1 to 4, wherein the activator is Eu. A plasma display device comprising a plasma display panel and a driving device for driving the plasma display panel, wherein the plasma display panel is the plasma display panel according to any one of claims 1 to 10. Display device. A phosphor that disperses an activator in a base material and emits visible light when excited by vacuum ultraviolet rays, wherein the concentration of the activator on the phosphor surface is smaller than the concentration of the activator inside the phosphor. A phosphor characterized in that: 13. The phosphor according to claim 12, wherein the concentration of the activator increases from the surface of the phosphor toward the inside. 13. The phosphor according to claim 12, comprising only a base material at a depth of 10 nm from the surface. 15. The phosphor according to claim 12, wherein the powder has a particle size of 0.1 μm or more and 5 μm or less. The phosphor according to any one of claims 12 to 15, wherein the base material is BaMgAl ₁₀ O ₁₇ , and the activator is Eu. 16. The phosphor according to claim 12, wherein the base material is BaMgAl ₁₀ O ₁₇ , and the activator is Mn. Base material _is a Zn 2 SiO _4, phosphor according to any one of claims 12 to 15, wherein the activator is Mn. Base material _is a _BaAl 12 _{O 19,} a phosphor according to any one of claims 12 to 15, wherein the activator is Mn. Base material is a YBO _3, phosphor according to any one of claims 12 to 15, wherein the activator is Tb. Base _{material, (Y X Gd 1-X} ) is BO _3, phosphor according to any one of claims 12 to 15, wherein the activator is Eu. A method for producing a phosphor, comprising mixing and firing a raw material of a base material and a raw material of an activator, and further mixing and firing the raw material of the base material. A method for producing a phosphor, characterized in that a raw material of a base material and a raw material of an activator are mixed and fired, and the raw material of the base material is further added during the firing.

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