JP2013127903A - Plasma display panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a red-color fluorescent material suitable for 3D PDP.SOLUTION: The plasma display panel comprises a red-color fluorescent material layer which emits visible light in response to vacuum ultraviolet light. The red-color fluorescent material layer comprises a fluorescent material represented by the general formula: (1-b)((1-a)GdOaYO) bEuO, where 0≤a≤0.5; and 0.005≤b≤0.15. The red-color fluorescent material layer further comprises a fluorescent material represented by the general formula in the proportion of 70 wt.% or less: p((1-q-r)GdOq(YO) r(EuO)) (1-s)POsVO, where 0.99≤p≤1.1; 0≤q≤0.99; 0.01≤r≤0.1; q+r≤1; and 0≤s≤0.95.

Description

  The present invention relates to a plasma display panel (PDP).

For the red phosphor for PDP, (Y, Gd) BO ₃ : Eu, which has a high luminance by vacuum ultraviolet light excitation, is widely used. (Y, Gd) BO ₃ : Eu is less degraded by the panel manufacturing process and exhibits good chromaticity due to an appropriate optical filter design. However, the afterglow time is relatively long as about 10 ms, and the moving image characteristic as the PDP is deteriorated by this long afterglow time. Further, in the 3D-PDP that can express a stereoscopic video, when the afterglow time becomes long, the moving image crosstalk (overlapping of the left-eye image and the right-eye image) deteriorates and the stereoscopic video breaks down. Therefore, a red phosphor having a short afterglow time is strongly demanded for PDP applications.

As a red phosphor for PDP, for example, Patent Document 1 discloses a method using (Y, Gd) ₂ O ₃ : Eu. Patent Document 2 discloses a method using (Y, Gd) (P, V) O ₄ : Eu. Patent Document 3 discloses a method in which (Y, Gd) ₂ O ₃ : Eu and (Y, Gd) (P, V) O ₄ : Eu are mixed and used.

JP-A-10-195432 Japanese Patent Laid-Open No. 11-73138 JP 2009-185275 A

However, according to detailed examinations by the inventors, the phosphors disclosed in Patent Documents 1 and 3 have a 1/10 afterglow time shorter than that of the (Y, Gd) BO ₃ : Eu red phosphor. -It has been found that the luminance is greatly reduced in order to obtain sufficiently short persistence for PDP. Furthermore, after 1/10 afterglow time, a very gentle decay process is exhibited, and afterglow time is very long as 1/100 afterglow time. For 3D-PDP, it has a strong influence on crosstalk. I understood it.

The phosphor disclosed in Patent Document 2 has an afterglow time shorter than that of the (Y, Gd) BO ₃ : Eu red phosphor, but is insufficient for 3D-PDP. Further, although the chromaticity is excellent, it has been found that it deteriorates in the panel manufacturing process and driving for image display, and the luminance is insufficient.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide a red phosphor suitable for 3D-PDP.

In order to solve the above-described problems, the present invention provides a plasma display panel including a red phosphor layer that emits visible light by vacuum ultraviolet rays, wherein the red phosphor layer has the general formula (1-b) ((1 characterized in that it comprises a phosphor represented by _{-a) Gd 2 O 3 · aY} 2 O 3) · bEu 2 O 3 (0 ≦ a ≦ 0.5,0.005 ≦ b ≦ 0.15) .

Furthermore, in the present invention, the red phosphor layer further includes the general formula p ((1-q-r) Gd ₂ O ₃ .q (Y ₂ O ₃ ) .r (Eu ₂ O ₃ )). (1- s) P ₂ O ₅ .sV ₂ O ₅ (0.99 ≦ p ≦ 1.1, 0 ≦ q ≦ 0.99, 0.01 ≦ r ≦ 0.1, q + r ≦ 1, 0 ≦ s ≦ 0. The phosphor represented by (95) is 70% by weight or less.

  According to the present invention, it is possible to provide a PDP with a short afterglow time, high efficiency, high luminance, and high color purity.

Schematic sectional view showing the structure of a PDP according to the present invention

  Hereinafter, embodiments of the present invention will be described in detail.

The first phosphor according to the present invention has a general formula (1-b) ((1-a) Gd ₂ O ₃ .aY ₂ O ₃ ) .bEu ₂ O ₃ (0 ≦ a ≦ 0.5, 0.01 ≦ b ≦ 0.15). Regarding a and b, preferred ranges from the viewpoint of luminance, afterglow time, and chromaticity are 0.05 <a ≦ 0.20 and 0.05 ≦ b ≦ 0.10.

Further, the second phosphor to be mixed with the first phosphor has the general formula p ((1-q-r ) Gd 2 O 3 · q (Y 2 O 3) · r (Eu 2 O 3)) (1-s) P ₂ O ₅ .sV ₂ O ₅ (1.001 ≦ p ≦ 1.1, 0 ≦ q ≦ 0.97, 0.03 ≦ r ≦ 0.1, q + r ≦ 1, 0 ≦ s ≦ 0.95).

  Hereinafter, although the manufacturing method of the fluorescent substance of this invention is demonstrated, the manufacturing method of the fluorescent substance of this invention is not restricted to the following.

  As a raw material, a high purity (purity 99% or more) hydroxide, carbonate, nitrate, or other compound that becomes an oxide upon firing, or a high purity (purity 99% or more) oxide can be used.

  In order to accelerate the reaction, it is preferable to add a small amount of fluoride (such as lithium fluoride) or chloride (such as barium chloride).

  The phosphor is produced by mixing and firing the above raw materials. The raw material may be mixed by wet mixing in a solution or dry mixing of a dry powder. A medium stirring mill, a planetary mill, a vibration mill, a jet mill, a V-type mixer, a stirrer, or the like can be used.

  The method for firing the mixed powder varies depending on the composition system of the phosphor. The first phosphor of the present invention is first fired in the atmosphere at a temperature range of 1100 to 1300 ° C. for about 1 to 50 hours. Further, firing is performed for about 1 to 50 hours in a temperature range of 1000 to 1400 ° C. in a specific oxygen partial pressure atmosphere such as nitrogen gas or carbon dioxide gas.

  The second phosphor is fired in the air at a temperature range of 1100 to 1400 ° C. for about 1 to 20 hours. The furnace used for firing may be an industrially used furnace, and a continuous or batch type electric furnace or gas furnace such as a pusher furnace may be used. The obtained phosphor powder is pulverized again using a ball mill, a jet mill or the like, and further washed or classified as necessary, thereby adjusting the particle size distribution and fluidity of the phosphor powder.

Since the phosphor of the present invention has high luminance and color purity, a highly efficient light-emitting device can be configured by applying the phosphor of the present invention to a light-emitting device having a phosphor layer. Specifically, conventional (Y, Gd) BO _3: the red phosphor such as Eu: the light-emitting device having a phosphor layer red phosphor is used, such as Eu, (Y, Gd) BO 3 What is necessary is just to substitute for the 1st or 2nd fluorescent substance of invention. Examples of the light emitting device include a PDP, a fluorescent panel, a fluorescent lamp (eg, a mercury-free fluorescent lamp), and among these, a PDP is preferable.

  Hereinafter, an AC surface discharge type PDP will be described as an example.

  FIG. 1 is a perspective sectional view showing the main structure of an AC surface discharge type PDP 10. For convenience, the PDP shown here is illustrated with a size setting in accordance with the 1024 × 768 pixel specification of the 42-inch class, but may be applied to other sizes and specifications. .

  As shown in FIG. 1, the PDP 10 includes a front panel 20 and a back panel 26 and is disposed so that the main surfaces thereof face each other.

  The front panel 20 includes a front panel glass 21 as a front substrate, strip-shaped display electrodes (X electrodes 23 and Y electrodes 22) provided on one main surface of the front panel glass 21, and a thickness covering the display electrodes. The front-side dielectric layer 24 having a thickness of about 30 μm and a protective layer 25 having a thickness of about 1.0 μm provided on the front-side dielectric layer 24 are included.

  The display electrode includes a strip-shaped transparent electrode 220 (230) having a thickness of 0.1 μm and a width of 150 μm, and a bus line 221 (231) having a thickness of 7 μm and a width of 95 μm provided on the transparent electrode. Yes. A plurality of pairs of display electrodes are arranged in the y-axis direction with the x-axis direction as the longitudinal direction.

  Each pair of display electrodes (X electrode 23, Y electrode 22) is electrically connected to a panel drive circuit (not shown) in the vicinity of the end of the front panel glass 21 in the width direction (y-axis direction). Has been. The Y electrodes 22 are collectively connected to the panel drive circuit, and the X electrodes 23 are independently connected to the panel drive circuit. When power is supplied to the Y electrode 22 and the specific X electrode 23 using the panel drive circuit, a surface discharge (sustain discharge) is generated in the gap (about 80 μm) between the X electrode 23 and the Y electrode 22. The X electrode 23 can also be operated as a scan electrode, and thereby, a write discharge (address discharge) can be generated between the X electrode 23 and an address electrode 28 described later.

  The back panel 26 includes a back panel glass 27 as a back substrate, a plurality of address electrodes 28, a back side dielectric layer 29, a partition wall 30, red (R), green (G), and blue (B). Phosphor layers 31 to 33 corresponding to any of them are included. The phosphor layers 31 to 33 are provided in contact with the side walls of two adjacent barrier ribs 30 and the back-side dielectric layer 29 therebetween, and are repeatedly arranged in the x-axis direction.

The red phosphor layer (R) includes the above-described red phosphor of the present invention. On the other hand, the green phosphor layer (G) and the blue phosphor layer (B) contain a general phosphor. For example, the green phosphor may be Zn ₂ SiO ₄ : Mn or a mixture of Zn ₂ SiO ₄ : Mn and Y ₃ Al ₅ O ₁₂ : Ce, and the blue phosphor may be BaMgAl ₁₀ O ₁₇ : Eu.

  For each phosphor layer, a phosphor ink in which phosphor particles are dissolved is applied to the partition wall 30 and the back side dielectric layer 29 by a known coating method such as a meniscus method or a line jet method, and this is dried or baked. (For example, 10 minutes at 500 ° C.). The phosphor ink comprises, for example, 30% by mass of a green phosphor having a volume average particle diameter of 2 μm, 4.5% by mass of ethyl cellulose having a weight average molecular weight of about 200,000, and 65.5% by mass of butyl carbitol acetate. Can be produced. Further, it is preferable to adjust the viscosity so that the viscosity finally becomes about 2000 to 6000 cps (2 to 6 Pas), because the adhesion force of the ink to the partition wall 30 can be increased.

  The address electrode 28 is provided on one main surface of the back panel glass 27. The back side dielectric layer 29 is provided so as to cover the address electrodes 28. The partition wall 30 has a height of about 150 μm and a width of about 40 μm, and is provided on the back-side dielectric layer 29 in accordance with the pitch of the adjacent address electrodes 28 with the y-axis direction as the longitudinal direction. Yes.

  Each of the address electrodes 28 has a thickness of 5 μm and a width of 60 μm, and a plurality of address electrodes 28 are arranged in the x-axis direction with the y-axis direction as the longitudinal direction. The address electrodes 28 are arranged so that the pitch is a constant interval (about 150 μm). The plurality of address electrodes 28 are independently connected to the panel drive circuit. By supplying power individually to each address electrode, it is possible to cause an address discharge between the specific address electrode 28 and the specific X electrode 23.

The front panel 20 and the back panel 26 are arranged so that the address electrodes 28 and the display electrodes are orthogonal to each other. The outer peripheral edge portions of both panels 20 and 26 are sealed by a frit glass sealing portion (not shown) as a sealing member. In a sealed space between the front panel 20 and the back panel 26 sealed by the frit glass sealing portion, a discharge gas composed of a rare gas component such as He, Xe, Ne or the like has a predetermined pressure (usually 6.7 × 10 6). ^{4 to} 1.0 × 10 ⁵ Pa).

  A space corresponding to the space between two adjacent barrier ribs 30 is a discharge space 34. A region where a pair of display electrodes and one address electrode 28 intersect with each other across the discharge space 34 corresponds to a cell displaying an image. In this example, the cell pitch in the x-axis direction is set to about 300 μm, and the cell pitch in the y-axis direction is set to about 675 μm.

  When driving the PDP 10, the panel drive circuit applies a pulse voltage to the specific address electrode 28 and the specific X electrode 23 to cause address discharge, and then a pair of display electrodes (X electrode 23, Y electrode 22). A pulse is applied during the period to sustain discharge. The phosphors contained in the phosphor layers 31 to 33 are caused to emit visible light using the short wavelength ultraviolet rays (resonance lines having a central wavelength of about 147 nm and molecular beams having a central wavelength of 172 nm) generated thereby. Thus, a predetermined image can be displayed on the front panel side.

  Hereinafter, the present invention will be described in detail with specific examples and comparative examples.

<Preparation of first phosphor sample>
Gd ₂ O ₃ and Eu ₂ O ₃ were used as starting materials, and these were weighed to a predetermined composition and dissolved in a 0.1 mol / L nitric acid aqueous solution. The dissolution was performed by heating to 80 ° C. Then, it co-precipitated with 0.4 mol / L oxalic acid aqueous solution. The precipitate was filtered and washed several times and dried. The dried powder was fired at 1300 ° C. for 4 hours in the air, and further fired in carbon dioxide gas at 1000 ° C. for 2 hours to obtain a phosphor. The amount of the nitric acid aqueous solution was about 35 L with respect to 1 kg of the raw material, and the amount of the oxalic acid aqueous solution was adjusted accordingly.

<Measurement of luminance and chromaticity>
The phosphor samples of Examples and Comparative Examples were irradiated with vacuum ultraviolet light having a wavelength of 146 nm in a vacuum, and the emission in the visible region was measured. Table 1 shows the composition ratio, CIE chromaticity coordinate value (x, y), 1/10 afterglow value, and 1/100 afterglow value of the produced phosphor. In Table 1, * 1 is a comparative example and is not subjected to heat treatment in carbon dioxide gas.

  As can be seen from Table 1, as the Eu concentration increases, the afterglow time can be reduced, and the 1/100 afterglow time is greatly reduced compared to the case where heat treatment in carbon dioxide gas is not performed. I understand that I can do it. In addition, phosphors having a composition ratio of 0.05 ≦ b ≦ 0.10 (sample numbers 2 to 4) have excellent red light emission color purity (large chromaticity x value and small y value). Among them, the phosphor having a composition ratio of b = 0.075 (sample numbers 3 and 4) has particularly good color purity. Note that b> 0.10 is not preferable because luminance decreases.

Table 2 shows the composition ratio, luminance (Y), chromaticity (x, y), and 1/10 afterglow value of the prepared phosphor. However, Y is the brightness | luminance Y in an international lighting committee XYZ color system, is a relative value with respect to the sample number 3, and has shown the brightness | luminance after transmitting the Ne cut filter used for general PDP. . In Table 2, * 2 to 4 are comparative examples, * 2 is not subjected to heat treatment in carbon dioxide gas, * 3 and * 4 are commercially available Y (P, V) O ₄ : Eu, (Y, Gd) BO ₃ : Eu.

As can be seen from Table 2, the afterglow value can be reduced with the amount of Gd substitution, and the luminance is further increased by performing heat treatment in carbon dioxide gas. A phosphor having a composition ratio within the composition range of the present invention has high luminance due to excitation by vacuum ultraviolet light, and exhibits good characteristics in both chromaticity coordinate values and afterglow time. In particular, phosphors (sample numbers 7 and 8) having a composition ratio in the composition range of 0.10 ≦ a ≦ 0.20 have particularly high luminance, and both chromaticity and afterglow values are Y (P, V). O ₄ : Eu, (Y, Gd) BO ₃ : shows characteristics over Eu.

<Luminance, chromaticity and afterglow time of panel using first and second phosphors>
A red phosphor similar to that of Sample Nos. 8 and * 3 above was mixed and used, and a PDP having the configuration of FIG. 1 was produced in the same manner as in the example of the AC surface discharge type PDP described above. About the produced PDP, panel initial luminance (relative value with respect to the case of using only sample number 1), chromaticity, and 1/10 afterglow time were measured. The results are shown in Table 3. The panel has a fixed red color display.

  As is apparent from Table 3, the afterglow time and panel brightness are improved without significantly deteriorating afterglow characteristics by using the second phosphor mixed with the first phosphor of the present invention. It has been confirmed. When the mixing amount of the second phosphor is 70% by weight or more, the effect of improving the afterglow time is not recognized, which is not preferable.

  By using the phosphor of the present invention, it is possible to provide a high-efficiency plasma display panel having a short afterglow time and high luminance and color purity.

10 PDP
20 Front panel 21 Front panel glass 22 Y electrode (display electrode)
23 X electrode (display electrode)
24 Front-side dielectric layer 25 Protective layer 26 Back panel 27 Back panel glass 28 Address electrode 29 Back-side dielectric layer 30 Bulkhead 31 Phosphor layer (R)
32 Phosphor layer (G)
33 Phosphor layer (B)
34 Discharge space 220 Transparent electrode 221 Bus line 230 Transparent electrode 231 Bus line

Claims (2)

A red phosphor layer that emits visible light by vacuum ultraviolet rays, wherein the red phosphor layer has the general formula (1-b) ((1-a) Gd ₂ O ₃ .aY ₂ O ₃ ) A plasma display panel comprising a phosphor represented by bEu ₂ O ₃ (0 ≦ a ≦ 0.5, 0.005 ≦ b ≦ 0.15). The red phosphor layer further has a general formula p ((1-qr) Gd ₂ O ₃ .q (Y ₂ O ₃ ) .r (Eu ₂ O ₃ )). (1-s) P ₂ O ₅ SV ₂ O ₅ (0.99 ≦ p ≦ 1.1, 0 ≦ q ≦ 0.99, 0.01 ≦ r ≦ 0.1, q + r ≦ 1, 0 ≦ s ≦ 0.95) The plasma display panel according to claim 1, wherein the plasma display panel contains 70% by weight or less of a phosphor.

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