JP3591461B2 - Phosphor material, phosphor film and plasma display panel - Google Patents

Description

【００６５】
パネルＮｏ．１〜４のＰＤＰは、前記実施の形態に基づいて作製した実施例に係わるＰＤＰであって、青色蛍光体Ｂａ（１−ｘ−ｙ）ＳｒｙＭｇＡｌ_１０Ｏ_１７：Ｅｕｘにおけるｘおよびｙを変化させたものである。なお、パネルＮｏ．５および６のＰＤＰは、比較例に係わるＰＤＰである。
【００６６】
なお、前記各ＰＤＰにおいて、蛍光体膜作製後の焼成は５２０℃、パネル張り合わせ時の焼成は４６０℃で行った。また、蛍光体膜厚は２０μｍ、放電ガス圧は５００Ｔｏｒｒに設定した。また、各ＰＤＰにおけるパネル輝度は、放電維持電圧が１５０Ｖ、周波数が３０ｋＨｚの放電条件で測定した。
【００６７】
なお、表中の輝度とは、白色表示の色温度を９５００度にするために、各色の信号を調整した場合の輝度である。
【００６８】
パネルの評価結果により、初期輝度はｘおよびｙに影響されｘ＝０．０５で、ｙが小さいパネル程輝度が高くなっている。また、５０００時間パネル点灯後の輝度では、ｘ＋ｙの値が大きくなるほど耐久性が向上している。これらの結果、特に、ｘ＝０．０５、ｙ＝０．０５（Ｎｏ．２）のパネルでの輝度向上が大きかった。
【００６９】
【発明の効果】
以上のように本発明の蛍光体材料を用いれば、耐熱性および耐久性の高い蛍光体膜が形成され、プラズマディスプレイパネル作製時の、焼成プロセスで熱劣化および点灯中の発光強度劣化が抑えられ、発光強度が高く、長寿命で画質の良好なプラズマディスプレイパネルが実現できる。
【図面の簡単な説明】
【図１】（ａ），（ｂ）本発明の一実施の形態の蛍光体材料の耐熱性を示す図
【図２】従来の蛍光体の耐久性を示す図
【図３】本発明の一実施の形態の蛍光体材料の耐久性を示す図
【図４】本発明の一実施の形態の蛍光体材料の耐熱性を示す図
【図５】本実施の形態で蛍光体層を形成する際に用いるインク塗布装置の概略構成図
【図６】本発明の一実施の形態に係わる交流面放電型プラズマディスプレイパネルの概略を示す断面図
【図７】従来の交流面放電型プラズマディスプレイパネルの概略断面図
【符号の説明】
１１ 前面ガラス基板（フロントカバープレート）
１２ 表示電極
１３ 誘電体ガラス層
１４ 誘電体保護層（ＭｇＯ）
１５ 背面ガラス基板（バックプレート）
１６ アドレス電極
１７ 可視光反射層
１８ 隔壁
１９ 蛍光体層[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a phosphor material and a phosphor film that emit light with high efficiency and long life, and a plasma display panel using rare gas discharge light emission used for a color television receiver or display for displaying characters or images. It is.
[0002]
[Prior art]
Hereinafter, a conventional plasma display panel will be described. FIG. 7 is a cross-sectional view schematically showing an AC type (AC type) plasma display panel.
[0003]
In FIG. 7, reference numeral 41 denotes a front cover plate (front glass substrate), on which display electrodes 42 are formed. Further, the front cover plate 41 on which the display electrodes 42 are formed is covered with a dielectric glass layer 43 and a magnesium oxide (MgO) dielectric protection layer 44.
[0004]
Reference numeral 45 denotes a rear glass substrate (back plate). On the rear glass substrate 45, address electrodes 46, partition walls 47, and phosphor layers (50 to 52) are provided. Discharge space. In the phosphor layer, three color phosphor layers of red 50, green 51, and blue 52 are sequentially arranged for color display. Each of the phosphor layers (50 to 52) emits and emits light by ultraviolet rays having a short wavelength (147 nm and 172 nm) generated by discharge.
[0005]
[Problems to be solved by the invention]
In a conventional plasma display panel, the phosphor layer is formed by applying an ink containing phosphor particles by a printing method or by coating a sheet containing the phosphor particles. .
[0006]
In either method, it is necessary to bake at about 500 ° C. after forming the phosphor layer in order to remove the organic binder component present in the ink or sheet.
[0007]
Further, in order to bond the front cover plate and the back plate, a baking process at 400 ° C. or higher is required again.
[0008]
In these firing processes, the phosphor used undergoes some degree of thermal change, causing a degradation in brightness or chromaticity. In particular, Ba (1-x) MgAl ₁₀ O ₁₇ : Eux, which is currently used as a blue phosphor, is significantly deteriorated by heat.
[0009]
Further, Ba (1-x) MgAl ₁₀ O ₁₇ : Eux used as the blue phosphor is easily damaged by vacuum ultraviolet rays (wavelengths of 147 nm and 172 nm), which are short wavelength excitation light of the plasma display panel. The light emission intensity decreases with the panel lighting time, and a problem remains in terms of life.
[0010]
As described above, in the blue phosphor of the plasma display panel, there is a problem that the phosphor material is thermally degraded in a baking process required for its manufacture and its life is short.
[0011]
Therefore, an object of the present invention is to provide a plasma display panel having a relatively high luminance and a long life by forming a phosphor film having good emission characteristics by improving a phosphor material.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, in the phosphor material of the present invention, x is 0.08 or less and 0.01 or more in the phosphor material whose composition is represented by Ba (1-xy) SryMgaAlbOc: Eux. It is characterized by the following.
[0013]
Conventional a blue phosphor _{Ba (1-x) MgAl 10} O 17: In the phosphor material such as EuX, the substitution amount of generally ^{Eu 2+} ions x are used those 0.1-0.15 ing.
[0014]
This is because the initial luminance increases as the Eu ²⁺ ion replacement amount increases, but the heat resistance tends to improve as the Eu ²⁺ ion replacement amount decreases. , X are around 0.1 to 0.15 because the brightness of the film becomes highest.
[0015]
On the other hand, from the viewpoint of the image quality of the panel, the evaluation of the chromaticity as well as the luminance is important, and the evaluation of the light emission intensity (the value obtained by dividing the luminance by the y value of the chromaticity) having these as parameters is important.
[0016]
Comparing the emission intensities, after firing at around 500 ° C., the value of x is approximately equal to or less than 0.1.
[0017]
Further, the plasma display panel needs to be baked at about 400 ° C. in order to bond the front and back panels, and although this temperature is lower than the sintering temperature of the phosphor at about 500 ° C., the emission intensity is deteriorated. . Therefore, by increasing the heat resistance by setting the substitution amount of Eu ²⁺ ions as in the configuration of the present invention, it becomes possible to realize a phosphor film having higher emission intensity than a conventional phosphor film.
[0018]
In the above configuration, x is preferably 0.075 or less and 0.02 or more.
[0019]
Further, x is preferably 0.06 or less and 0.03 or more.
[0020]
Moreover, it is preferable that y is 0.2 or less and 0.01 or more.
[0021]
In general, the lifetime (ultraviolet resistance) of Ba (1-x) MgAl ₁₀ O ₁₇ : Eux tends to be longer as the substitution amount of Eu ²⁺ ions increases. However, there is a trade-off relationship with heat resistance as described above. The life of Ba (1-x) MgAl ₁₀ O ₁₇ : Eux can be improved by replacing part of Ba with Sr. Therefore, by lowering the substitution amount of Eu ²⁺ ions as in the configuration of the present invention and simultaneously reducing the substitution amount of Sr as in the configuration of the present invention, the heat resistance is higher than that of the conventional phosphor, and the lifetime is longer. Can be realized.
[0022]
In the above configuration, y is preferably 0.2 or less and 0.01 or more.
[0023]
Further, it is preferable that y is 0.15 or less and 0.02 or more.
[0024]
Further, it is preferable that y is 0.1 or less and 0.02 or more.
[0025]
Further, it is preferable that x + y is 0.2 or less and 0.05 or more.
[0026]
Furthermore, it is preferable that x + y is 0.15 or less and 0.09 or more.
[0027]
Further, a phosphor film of the present invention is characterized by being composed of the above phosphor material. Furthermore, in the plasma display panel of the present invention, electrodes and phosphor layers of a plurality of colors are arranged between a pair of parallelly arranged plates, and a discharge space in which a gas medium is sealed is formed. A plasma display panel that emits ultraviolet light and emits light by converting it into visible light with the phosphor layer, wherein at least one phosphor layer of the phosphor layer is formed of the phosphor film. Features.
[0028]
BEST MODE FOR CARRYING OUT THE INVENTION
(Embodiment)
Hereinafter, a plasma display panel according to an embodiment of the present invention will be described. FIG. 6 is a sectional view schematically showing an AC surface discharge type plasma display panel according to the present embodiment. Although only one cell is shown in FIG. 6, a PDP is configured by arranging a large number of cells that emit red, green, and blue light.
[0029]
This PDP includes a front panel in which a display electrode 12, a dielectric glass layer 13 and a protective layer 14 are disposed on a front glass substrate (front cover plate) 11, an address electrode 16 on a rear glass substrate (back plate) 15, A back panel on which the visible light reflecting layer 17, the partition wall 18 and the phosphor layer 19 are arranged is laminated, and a discharge gas is sealed in a discharge space formed between the front panel and the back panel. It is manufactured as shown in FIG.
[0030]
(Preparation of front panel)
The front panel is manufactured by forming a display electrode 12 on a front glass substrate 11, covering the display electrode 12 with a lead-based dielectric glass layer 13, and forming a protective layer 14 on the surface of the dielectric glass layer 13. .
[0031]
In the present embodiment, the display electrode 12 is a silver electrode, and is formed by a method in which a paste for a silver electrode is screen-printed and then fired. Further, the composition of the dielectric glass layer 13 of the lead-based, lead oxide [PbO] 70 _{wt%, [2 O 3 B]} 15 % by weight boron oxide, a silicon oxide _[SiO 2] 15% by weight, screen printing The film was formed to a thickness of about 20 μm by the method and firing.
[0032]
Next, a protective layer 14 of magnesium oxide (MgO) having a thickness of 1.0 μm was formed on the dielectric glass layer 13 by a CVD method (chemical vapor deposition method).
[0033]
(Production of back panel)
An address electrode 16 is formed on the back glass substrate 15 by a method of screen-printing a silver electrode paste and then firing the same, and a visible light reflecting layer made of TiO ₂ particles and dielectric glass is formed thereon by screen printing and firing. 17 and a glass partition wall 18 obtained by repeating the same screen printing and then sintering at a predetermined pitch.
[0034]
Then, a phosphor layer 19 is formed by disposing one of a red phosphor, a green phosphor, and a blue phosphor in each space sandwiched by the partition walls 18. The method of forming the phosphor layer 19 and the phosphor material to be used will be described later in detail, but the phosphor ink is applied by a method of scanning while continuously ejecting the phosphor ink from the nozzle, and after the application, about 500 ° C. And fired in air.
[0035]
In the present embodiment, the height of the partition walls is 0.1 to 0.15 mm and the partition wall pitch is 0.15 to 0.3 mm in accordance with a 40-inch class high-definition television. The phosphor layer 19 formed on the back cover surface and the side wall of the partition wall was composed of phosphor particles having an average particle size of 1 to 7 μm and had a thickness of 5 to 50 μm.
[0036]
(Production of PDP by panel bonding)
Next, the front panel and the rear panel manufactured as described above are bonded together using a sealing glass so that the front panel, the display electrode, and the address electrode are orthogonal to each other, fired at about 450 ° C., and separated by the partition wall 18. The discharge space is evacuated to a high vacuum (8 × 10 ⁻⁷ Torr), and a discharge gas having a predetermined composition is sealed at a predetermined pressure to produce a PDP.
[0037]
In this embodiment, the content of Xe in the discharge gas is set to 5% by volume, and the filling pressure is set in the range of 500 to 800 Torr.
[0038]
(About the method of forming the phosphor layer)
FIG. 5 is a schematic configuration diagram of an ink coating device 20 used when forming the phosphor layer 19. As shown in FIG. 5, in the ink application device 20, the phosphor ink is stored in the server 21, and the pressurizing pump 22 pressurizes the ink and supplies the pressurized ink to the header 23. An ink chamber 23a and a nozzle 24 are provided in the header 23, and the ink that has been pressurized and supplied to the ink chamber 23a is continuously ejected from the nozzle 24.
[0039]
The phosphor ink is prepared by mixing phosphor material particles of each color, a binder, a solvent component, and, if necessary, a surfactant, silica and the like so as to have an appropriate viscosity.
[0040]
In addition, as a method for forming the phosphor layer, a method of applying a phosphor ink by a screen printing method, a method of producing a sheet containing a phosphor material, and a method of attaching the sheet can be used. is there.
[0041]
(About phosphor material)
As the phosphor material constituting the phosphor ink, a material generally used for a phosphor layer of a PDP other than blue can be used. As a specific example,
“Green phosphor”: Zn ₂ SiO ₄ : Mn or BaAl ₁₂ O ₁₉ : Mn
"Red phosphor": _YBO 3: Eu or _{(YxGd1-x) BO 3:} Eu
Can be mentioned.
[0042]
As the blue phosphor, Ba (1-xy) SryMgaAlbOc: Eux was used.
[0043]
In order to obtain a phosphor film having good emission characteristics, it is necessary to consider the heat resistance of these phosphor materials to be used. Figure 1 (a) (b) to Ba0.95-xSr0.05MgAl ₁₀ O _17: Eux of the phosphor material and _Ba1-xMgAl 10 _O 17: firing process before and after the time of changing the x in EuX, relative emission intensity Are respectively shown. The relative emission intensity, Ba0.9MgAl ₁₀ O _17: the emission intensity before firing Eu0.1 was relatively compared as 100.
[0044]
The solid line in FIG. 1 is the characteristic of each phosphor before firing, the broken line is the characteristic after firing the phosphor at 520 ° C. in air, and the dashed line is the firing at 460 ° C. in air after firing at 520 ° C. The later characteristics are shown. Ba0.95-xSr0.05MgAl ₁₀ O _17: Eux and _Ba1-xMgAl 10 _O 17: Eux shows the same tendency as either, but the emission intensity comparison, is 1 to 2% of the emission intensity who does not contain Sr Got higher.
[0045]
In comparison of the emission intensities after baking with each material, after baking at 520 ° C., the values were almost equal at x = 0.1 or less, and after baking at 460 ° C., x = 0.03 to 0. It became the highest around 0.06.
[0046]
Thus, in the emission intensity evaluation, the emission intensity tends to decrease with baking at x = 0.08 or more, whereas the emission intensity may increase by baking at x = 0.08 or less. In the case where the heating of the phosphor was repeated twice or more as in the case of producing a plasma display panel, the best characteristics were obtained when x = 0.03 to 0.06.
[0047]
It is considered that the reason for this is that when the amount of Eu is relatively large, the Eu ²⁺ ions are easily oxidized during firing, so that the emission intensity is deteriorated.
[0048]
On the other hand, when the amount of Eu is relatively small, it is considered that Eu ²⁺ ions are less oxidized during firing, and the emission intensity is improved by removing impurities such as moisture by firing and improving crystallinity.
[0049]
Incidentally, the trend of improving higher heat resistance Eu amount is small, Ba0.95-xSr0.05MgAl ₁₀ O _17: not limited to Eux, Ba (1-x- y) SryMgAl 10 O 17: In Eux The same tendency was exhibited irrespective of the Sr amount y, and the best characteristics were obtained near x = 0.03 to 0.06 in consideration of the emission intensity before firing.
[0050]
Further, the phosphor whose composition using Eu ²⁺ ion as an activator is represented by Ba (1-xy) SryMgaAlbOc: Eux is limited to Ba (1-xy) SryMgAl ₁₀ O ₁₇ : Eux. Instead, similar results were obtained using Ba (1-xy) SryMgAl ₁₄ O ₂₃ : Eux or the like.
[0051]
On the other hand, the blue phosphor used for the plasma display panel has a problem in terms of life, and it is necessary to study the durability of the phosphor material used.
[0052]
FIG. 2 shows the durability of the phosphor material of Ba1-xMgAl ₁₀ O ₁₇ : Eux when x is changed. The vertical axis represents the light emission intensity after lighting for 5000 hours when the light emission intensity at the beginning of panel lighting is 100, and the horizontal axis represents x.
[0053]
In the conventional blue phosphor Ba1-xMgAl ₁₀ O ₁₇ : Eux, the durability increases as x increases. This is probably because the Eu ion substituted with the Ba ion has a smaller ionic radius than the Ba ion, so that as x increases, the bond distance between Eu and oxygen decreases and the bond energy increases.
[0054]
However, in Ba1-xMgAl ₁₀ O ₁₇ : Eux, the x dependency on durability has a trade-off relationship with the x dependency on heat resistance, and x was used at about 0.1 to 0.15.
[0055]
FIG. 3 shows the durability of the phosphor material of Ba (0.95-y) SryMgAl ₁₀ O ₁₇ : Eu0.05 when y is changed. The vertical axis represents the light emission intensity after lighting for 5000 hours when the light emission intensity at the beginning of panel lighting is 100, and the horizontal axis represents y. When the amount of Eu (x) is constant, the durability increases as y increases. This is because, as in the case of the Eu dependence, the Sr ion substituted with the Ba ion has a smaller ionic radius than the Ba ion, so that as y increases, the bond distance between Eu and oxygen decreases, and the bond energy decreases. Is considered to be stronger.
[0056]
Further, FIG. 4 Ba0.95-ySryMgAl ₁₀ O _17: phosphor material Eu0.05, after firing at 460 ° C. In addition in air after 520 ° C. firing shows y dependency of relative emission intensity. The relative luminous intensity was relatively compared with the luminous intensity before firing of y = 0 (Ba0.95MgAl ₁₀ O ₁₇ : Eu0.05) as 100. It can be seen that the emission intensity decreases with an increase in Sr, but only decreases by about 8% when y is up to 0.2 as compared with a phosphor containing no Sr.
[0057]
As described above, in the conventional blue phosphor Ba1-xMgAl ₁₀ O ₁₇ : Eux, there is a problem that if x is reduced in order to increase heat resistance, the durability is deteriorated. Although used in the range of 1 to 0.15, as in the present embodiment, in the phosphor represented by Ba (1-xy) SryMgAl ₁₀ O ₁₇ : Eux containing Sr, the Eu amount x Is set to 0.08 to 0.01 and the Sr amount y is set to 0.2 to 0.01 or less, a phosphor material having both improved heat resistance and durability over the conventional phosphor can be obtained.
[0058]
The heat resistance is further improved when x is 0.075 or less and 0.02 or more, and the best is obtained when x is 0.06 or less and 0.03 or more. Further, in terms of the total effect of heat resistance and durability, y is 0.15 or less and 0.02 or more, and further improved, and y is 0.1 or less, 0.02 or more, and the best.
[0059]
Further, since x and y each affect heat resistance and durability, in consideration of these effects, x + y is desirably 0.2 or less, 0.05 or more, and 0.15 or less. , 0.09 or more was the optimum value.
[0060]
Each color phosphor used in the present embodiment can be manufactured as follows. Blue phosphor, first, barium carbonate (BaCO _3), magnesium carbonate (MgCO _3), aluminum oxide _{(α-Al 2 O 3)} , strontium carbonate (SrCO _3), europium oxide _(Eu 2 _{0 3)} a predetermined Mix by volume. Then, it is mixed with an appropriate amount of flux (AlF ₂ , BaCl ₂ ) by a ball mill, and fired at 1400 ° C. to 1650 ° C. for a predetermined time (for example, 0.5 hour) in a weak reducing atmosphere (in H ² , N ² ). Get it.
[0061]
The red phosphor is blended with yttrium hydroxide Y ₂ (OH) ₃ and boric acid (H ₃ BO ₃ ) as raw materials so that the atomic ratio of Y and B is 1: 1. Next, a predetermined amount of europium oxide (Eu ₂ O ₃ ) is added to the mixture, mixed with a suitable amount of flux by a ball mill, and fired in air at 1200 ° C. to 1450 ° C. for a predetermined time (for example, 1 hour). obtain.
[0062]
Green phosphor, as raw materials of zinc oxide (ZnO), formulated to be a silicon oxide (Si0 ₂₎ Zn, the atomic ratio of 2: 1 of Si. Next, a predetermined amount of manganese oxide (Mn ₂ O ₃ ) is added to the mixture, mixed with a ball mill, and fired in air at 1200 ° C. to 1350 ° C. for a predetermined time (for example, 0.5 hour).
[0063]
(Example)
[0064]
[Table 1]

[0065]
Panel No. PDPs Nos. 1 to 4 are PDPs according to the examples manufactured based on the above embodiment, and x and y in the blue phosphor Ba (1-xy) SryMgAl ₁₀ O ₁₇ : Eux were changed. Things. Note that the panel No. PDPs 5 and 6 are PDPs according to the comparative example.
[0066]
In each of the above PDPs, baking was performed at 520 ° C. after the phosphor film was formed, and baking was performed at 460 ° C. when bonding the panels. The phosphor film thickness was set to 20 μm, and the discharge gas pressure was set to 500 Torr. The panel luminance in each PDP was measured under a discharge condition of a discharge sustaining voltage of 150 V and a frequency of 30 kHz.
[0067]
Note that the luminance in the table is the luminance when the signals of the respective colors are adjusted in order to set the color temperature of white display to 9500 degrees.
[0068]
According to the evaluation result of the panel, the initial luminance is affected by x and y, and x = 0.05, and the panel having a smaller y has a higher luminance. Further, in the luminance after the panel has been turned on for 5000 hours, the durability increases as the value of x + y increases. As a result, the improvement in luminance was particularly large in the panel where x = 0.05 and y = 0.05 (No. 2).
[0069]
【The invention's effect】
As described above, when the phosphor material of the present invention is used, a phosphor film having high heat resistance and high durability is formed, and during plasma display panel fabrication, thermal degradation in the firing process and emission intensity degradation during lighting are suppressed. In addition, a plasma display panel having high emission intensity, long life, and good image quality can be realized.
[Brief description of the drawings]
1A and 1B are diagrams showing heat resistance of a phosphor material according to an embodiment of the present invention. FIG. 2 is a diagram showing durability of a conventional phosphor. FIG. FIG. 4 is a diagram showing the durability of the phosphor material according to the embodiment. FIG. 4 is a diagram showing the heat resistance of the phosphor material according to the embodiment of the present invention. FIG. FIG. 6 is a cross-sectional view schematically showing an AC surface discharge type plasma display panel according to an embodiment of the present invention. FIG. 7 is a schematic view showing a conventional AC surface discharge type plasma display panel. Cross-sectional view [Explanation of reference numerals]
11 Front glass substrate (front cover plate)
12 display electrode 13 dielectric glass layer 14 dielectric protection layer (MgO)
15 Back glass substrate (back plate)
16 Address electrode 17 Visible light reflecting layer 18 Partition wall 19 Phosphor layer

Claims (8)

A phosphor material represented by Ba (1-xy) SryMgaAlbOc: Eux (a = 1, b = 10, c = 17), wherein x is 0.08 or less, 0.01 or more, and y Is 0.2 or less and 0.01 or more. A phosphor material represented by Ba (1-xy) SryMgaAlbOc: Eux (a = 1, b = 14, c = 23), wherein x is 0.08 or less, 0.01 or more, and y Is 0.2 or less and 0.01 or more. 3. The phosphor material for a plasma display panel according to claim 1, wherein x is 0.075 or less and 0.02 or more. 3. The phosphor material for a plasma display panel according to claim 1, wherein x is 0.06 or less and 0.03 or more. 5. The phosphor material for a plasma display panel according to claim 1, wherein y is 0.15 or less and 0.02 or more. 5. The phosphor material for a plasma display panel according to claim 1, wherein y is 0.1 or less and 0.02 or more. 7. The phosphor material for a plasma display panel according to claim 1, wherein x + y is 0.2 or less and 0.05 or more. 7. The phosphor material for a plasma display panel according to claim 1, wherein x + y is 0.15 or less and 0.09 or more.

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