JP2008277100A - Plasma display panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma display panel in which high visibility is secured by suppressing the increase in an L<SP>*</SP>value. <P>SOLUTION: In the PDP, the front plate obtained by forming a display electrode, a dielectric layer and a protective layer, and the rear plate obtained by forming an electrode, a barrier rib and a phosphor layer on the substrate are arranged opposite to each other, and the periphery thereof is sealed to form a discharge space. The display electrode contains silver as a main component, and the dielectric layer covers the display electrode and contains 5 to 12 wt.% of a compound expressed by R<SB>2</SB>O (R is at least one kind selected from Li, Na, K, Rb and Cs), and 0.1 to 2 wt.% of copper oxide (CuO). Moreover, the dielectric layer does not mainly contain a lead component, and contains 5 to 15 wt.% of bismuth oxide(Bi<SB>2</SB>O<SB>3</SB>). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a dielectric layer of a plasma display panel.

  In recent years, expectations for high-quality televisions with large screens have increased. Conventional CRTs are superior to plasma display panels (hereinafter referred to as PDPs) and liquid crystals in terms of resolution and image quality, but are not suitable for large screens of 40 inches or more in terms of depth and weight. is there. In addition, the liquid crystal has excellent performance such as low power consumption and low driving voltage, but there is a limit to a large screen and a viewing angle. On the other hand, the PDP can realize a narrow depth on a large screen, and a 60-inch class product has already been developed.

  A PDP basically includes a front plate and a back plate. The front plate covers a display electrode composed of a glass substrate of sodium borosilicate glass by a float method, a striped transparent electrode formed on one main surface of the glass substrate, and a main electrode. The dielectric layer functions as a capacitor, and a protective layer made of magnesium oxide (MgO) formed on the dielectric layer. On the other hand, the back plate is a glass substrate, stripe-shaped address electrodes formed on one main surface thereof, a base dielectric layer covering the address electrodes, a partition formed on the base dielectric layer, It is comprised with the fluorescent substance layer which light-emits each of red, green, and blue formed between the partition walls.

  The front plate and the back plate are hermetically sealed with the electrode forming surfaces facing each other, and Ne—Xe discharge gas is sealed at a pressure of 55 kPa to 80 kPa in a discharge space (each discharge cell) partitioned by a partition wall. Yes. PDP discharges by selectively applying a video signal voltage to the display electrode, and the ultraviolet rays generated by the discharge excite each color phosphor layer to emit red, green and blue light, thereby realizing color image display is doing.

  As described above, the display electrode is composed of a transparent electrode and a main electrode. Further, the main electrode is a silver electrode or a bus electrode made of Cr—Cu—Cr, a ruthenium compound, a ruthenium oxide, a copper-iron-based, and a cobalt black. It is comprised from the black electrode formed using this complex oxide and glass powder.

The black electrode is formed between the transparent electrode and the bus electrode by using the above-described paste containing the black complex oxide and the glass powder for the purpose of suppressing the reflection of external light and improving the bright place contrast. For the same purpose as the black electrode, a light shielding layer called a black stripe is disposed between the two transparent electrodes. At present, the black electrode and the light shielding layer are sometimes formed of the same material (see, for example, Patent Document 1).
JP 2004-063247 A

  The dielectric layer is required to have a high withstand voltage and a high light transmittance, but this characteristic greatly depends on the composition of the glass component contained in the dielectric layer.

  Conventionally, as a method for forming such a dielectric layer, a paste composed of a binder component composed of a glass powder component and a resin-containing solvent, a plasticizer, a dispersant, and the like is used by a screen printing method or a die coating method. A method of applying the electrode on a front glass substrate on which an electrode is formed, and baking it at about 450 ° C. to 600 ° C. after drying; or applying the paste on a film, drying it, and transferring it to the front plate on which the electrode is formed; A method of baking at about 600 to 600 ° C. is known.

In the past, in order to enable firing at about 450 ° C. to 600 ° C., the glass component contained in the dielectric layer contained 20% by weight or more of lead oxide. For consideration, there is a technical example in which glass contains bismuth oxide without containing lead oxide. In addition, in order to reduce the power consumption by reducing the charge capacity of the discharge cell and reducing the discharge power, the content of bismuth oxide is reduced, and about 0.5 to 15% by weight of R ₂ O (R is Li, There is also a technical example including an alkali metal oxide represented by (at least one selected from Na, K, Rb, and Cs).

However, depending on the range of the R ₂ O component in the dielectric layer or the concentration range of other additive components, the reducing action of the glass becomes stronger and reacts with the glass frit contained in the black electrode, Since the lightness (L ^* value) of the black electrode increases, the bright place contrast may be lowered.

An object of the present invention is to solve such problems and to realize a PDP that ensures high visibility even when R ₂ O is contained in a dielectric glass.

In the PDP of the present invention, a front plate in which a display electrode, a dielectric layer, and a protective layer are formed on a glass substrate, and a back plate in which an electrode, a partition wall, and a phosphor layer are formed on the substrate are arranged to face each other. And the display electrode is composed mainly of silver, the dielectric layer covers the display electrode, and R ₂ O (R is Li, Na, K, 5% to 12% by weight of a component represented by at least one selected from Rb and Cs) and 0.1 to 2% by weight of copper oxide (CuO). The dielectric layer is characterized in that it contains mainly no bismuth component and 5 to 15% by weight of bismuth oxide (Bi ₂ O ₃ ).

With the above configuration, the present invention can provide a PDP that suppresses an increase in L ^* value and ensures high visibility.

  Hereinafter, a PDP according to an embodiment of the present invention will be described with reference to the drawings.

(Embodiment)
FIG. 1 is a perspective view showing the structure of PDP 1 in the present embodiment.

  On the front glass substrate 3 of the front plate 2, a pair of strip-like display electrodes 6 and light-shielding layers (black stripes) 7 composed of the scanning electrodes 4 and the sustain electrodes 5 are arranged in a plurality of rows in parallel with each other. A dielectric layer 8 serving as a capacitor is formed on the front glass substrate 3 so as to cover the display electrode 6 and the light shielding layer 7, and a protective layer 9 made of magnesium oxide (MgO) is formed on the surface. Has been.

  On the back glass substrate 11 of the back plate 10, a plurality of strip-like address electrodes 12 are arranged in parallel to each other in a direction perpendicular to the scanning electrodes 4 and the sustain electrodes 5 of the front plate 2. Layer 13 is covering. Further, a partition wall 14 having a predetermined height is formed on the base dielectric layer 13 between the address electrodes 12 to divide the discharge space 16. For each address electrode 12, a phosphor layer 15 that emits red, blue, and green light by ultraviolet rays is sequentially applied to the grooves between the barrier ribs 14 and formed. A discharge cell is formed at a position where the scan electrode 4 and the sustain electrode 5 intersect with the address electrode 12, and the discharge cell having red, blue and green phosphor layers 15 arranged in the direction of the display electrode 6 is used for color display. Become a pixel.

  The front plate 2 and the back plate 10 formed as described above are arranged to face each other, and the outer peripheral portion thereof is hermetically sealed with a sealing material made of glass frit or the like. The discharge space 16 inside the sealed PDP 1 is filled with a discharge gas such as Ne and Xe at a pressure of 55 kPa to 80 kPa.

FIG. 2 is a cross-sectional view of the front plate 2 showing the configuration of the dielectric layer 8 of the PDP in the present embodiment. 2 is shown upside down from FIG. As shown in FIG. 2, a display electrode 6 and a light shielding layer 7 including scanning electrodes 4 and sustain electrodes 5 are formed in a pattern on a front glass substrate 3 manufactured by a float method or the like. Scan electrode 4 and sustain electrode 5 are transparent electrodes 4a and 5a made of ITO, SnO ₂ or the like, metal bus electrodes 4b and 5b made of a conductive material mainly composed of a silver material, a ruthenium compound or a ruthenium oxide, respectively. , Copper-iron-based, cobalt black complex oxide, and black electrodes 4c and 5c made of glass powder.

  The metal bus electrodes 4b and 5b are used for the purpose of imparting electrical conductivity in the longitudinal direction of the transparent electrodes 4a and 5a, and the black electrodes 4c and 5c are used for the purpose of suppressing the reflection of external light and improving the bright place contrast. . Therefore, for these purposes, black electrodes 4c and 5c are formed on the transparent electrodes 4a and 5a, and metal bus electrodes 4b and 5b are formed on the black electrodes 4c and 5c.

  The dielectric layer 8 includes a dielectric layer 8 provided on the front glass substrate 3 so as to cover the transparent electrodes 4a and 5a, the metal bus electrodes 4b and 5b, and the light shielding layer 7, and further on the dielectric layer 8. A protective layer 9 is formed.

  Next, a method for manufacturing the PDP 1 will be described. First, the scan electrode 4, the sustain electrode 5, and the light shielding layer 7 are formed on the front glass substrate 3. The transparent electrodes 4a and 5a, the metal bus electrodes 4b and 5b, and the black electrodes 4c and 5c are formed by patterning using a photolithography method or the like. The transparent electrodes 4a and 5a are formed using a thin film process or the like, and the metal bus electrodes 4b and 5b are solidified by baking a paste containing a silver material at a desired temperature. In addition, the black electrodes 4c and 5c and the light shielding layer 7 are formed in the same step by screen printing a paste containing a black pigment or forming a black pigment on the entire surface of the glass substrate, and then patterning and baking using a photolithography method. Is formed.

  Next, a dielectric paste is applied on the front glass substrate 3 by a die coating method or the like so as to cover the scan electrode 4, the sustain electrode 5, and the light shielding layer 7, thereby forming a dielectric paste layer (dielectric material layer). After the dielectric paste is applied, the surface of the applied dielectric paste is leveled by leaving it to stand for a predetermined time, so that a flat surface is obtained. Thereafter, the dielectric paste layer is baked and solidified to form the dielectric layer 8 that covers the scan electrode 4, the sustain electrode 5, and the light shielding layer 7. The dielectric paste is a paint containing a dielectric material such as glass powder, a binder and a solvent. Next, a protective layer 9 made of magnesium oxide (MgO) is formed on the dielectric layer 8 by a vacuum deposition method. Through the above steps, predetermined components (scanning electrode 4, sustaining electrode 5, light shielding layer 7, dielectric layer 8, and protective layer 9) are formed on front glass substrate 3, and front plate 2 is completed.

  On the other hand, the back plate 10 is formed as follows. First, the structure for the address electrode 12 is formed by a method of screen printing a paste containing silver (Ag) material on the rear glass substrate 11 or a method of patterning using a photolithography method after forming a metal film on the entire surface. An address electrode 12 is formed by forming a material layer to be an object and firing it at a desired temperature. Next, a dielectric paste is applied on the rear glass substrate 11 on which the address electrodes 12 are formed by a die coating method so as to cover the address electrodes 12 to form a dielectric paste layer. Thereafter, the base dielectric layer 13 is formed by firing the dielectric paste layer. The dielectric paste is a paint containing a dielectric material such as glass powder, a binder and a solvent.

  Next, a partition wall forming paste including a partition wall material is applied on the base dielectric layer 13 and patterned into a predetermined shape to form a partition wall material layer and then fired to form the partition walls 14. Here, as a method of patterning the partition wall paste applied on the base dielectric layer 13, a photolithography method or a sand blast method can be used. Next, the phosphor layer 15 is formed by applying a phosphor paste containing a phosphor material on the base dielectric layer 13 between the adjacent barrier ribs 14 and on the side surfaces of the barrier ribs 14 and baking it. Through the above steps, the back plate 10 having predetermined components on the back glass substrate 11 is completed.

  In this way, the front plate 2 and the back plate 10 provided with predetermined constituent members are arranged to face each other with high precision so that the scanning electrode 4, the sustain electrode 5 and the address electrode 12 are orthogonal to each other, and the periphery thereof is made of glass frit. The PDP 1 is completed by sealing and enclosing a discharge gas containing Ne, Xe or the like in the discharge space 16.

Next, the dielectric layer 8 of the front plate 2 will be described in detail. The glass component contained in the dielectric layer 8 is composed mainly of components other than lead (Pb) -based components, and further includes at least one selected from copper oxide (CuO) and R ₂ O (R is Li, Na, K, Rb and Cs). It is comprised by the material composition containing a seed.

  A dielectric material powder is produced by pulverizing a dielectric material composed of these composition components with a wet jet mill or a ball mill so that the average particle size is 0.5 μm to 2.5 μm. Next, the dielectric material powder 55 wt% to 70 wt% and the binder component 30 wt% to 45 wt% are well kneaded with three rolls to prepare a dielectric layer paste for die coating or printing.

  The binder component is terpineol or butyl carbitol acetate containing 1% to 20% by weight of ethyl cellulose or acrylic resin. In the paste, dioctyl phthalate, dibutyl phthalate, triphenyl phosphate, and tributyl phosphate are added as plasticizers as needed, and glycerol monooleate, sorbitan sesquioleate, and homogenol (Kao Corporation) as dispersants. The printability may be improved by adding a phosphoric ester of an alkyl allyl group or the like.

  Next, this dielectric layer paste is applied to the front glass substrate 3 so as to cover the display electrodes 6 by a screen printing method, a spray method, a blade coater method, or a die coating method, and then dried. And firing at 450 ° C. to 600 ° C.

By having the dielectric layer 8 formed in this way, it is possible to suppress an increase in the L ^* value. In the following, the results of study on suppression of L ^* value increase will be described.

  First, the examination method will be described. The glass paste on the dielectric layer of the sample is composed of a binder component consisting of a glass powder component and a solvent containing a resin, and after blending the various components to the desired composition, homogenize with a disperser such as a three-roller. And mixed and dispersed.

  Then, a display electrode test pattern is formed on a glass substrate on which a transparent electrode is formed, and a glass paste is applied by a die coating method so as to cover it, dried, and baked at 600 ° C. to form a dielectric layer. This was used as a sample.

The L ^* value indicating the degree of visibility was measured with a color meter (CR-300 manufactured by Minolta). It should be noted that the standard of the L ^* value that affects the visibility of the PDP is preferably 45 or less under the measurement conditions in the present embodiment. The smaller this value, the lower the black luminance and the image display. A PDP with good time contrast can be obtained.

Under these conditions, an example having the material composition of the dielectric layer corresponding to this embodiment and a sample serving as a comparative example were prepared, and the L ^* value was measured. Table 1 shows the main component content (unit:% by weight) of the glass powder component of the glass paste used for each sample and the measurement results. Examples 1 to 4 are shown in Table 1 as samples corresponding to the present embodiment. Comparative examples 1 and 2 are shown as a comparison with the prior art.

As shown in Table 1, none of the samples contained a lead (Pb) -based component in the glass component, and in Examples 1, 2, 3, and 4, all of the R ₂ O And copper oxide (CuO). On the other hand, Comparative Example 1 does not contain both R ₂ O and copper oxide (CuO). Although Comparative Example 2 contains the R ₂ O, copper oxide (CuO) are not included.

From these results, in Examples 1 to 4 in the embodiment of the present invention, the L ^* value is as low as 38.7 to 42.5, and the comparative example does not include both R ₂ O and copper oxide (CuO). It can be seen that the increase in the physical property value is suppressed compared to 1. On the other hand, the R ₂ O contains the same concentration as in Examples 1 to 4, but in Comparative Example 2 not containing copper oxide (CuO), the L ^* value was 46.0, and the L ^* value increased. I can see that Although not shown in Table 1, although it contains the R ₂ O, its content is less than those in Examples 1 to 4, and even in a sample containing copper oxide (CuO), good L ^* No value was obtained.

Moreover, when copper oxide (CuO) was added exceeding 2% by weight, coloring of the dielectric layer became strong, and a change in chromaticity during image display was observed. Similarly, the content of R ₂ O is desirably 5% by weight to 12% by weight, and if it exceeds this range, a problem that discoloration of the front glass substrate 3 due to diffusion of silver from the display electrode 6 occurs. In addition, the content of R ₂ O is preferably 5% by weight or more because of the limitation of the temperature condition at the time of firing the dielectric layer 8.

Although details about the mechanism of these phenomena are unclear, when the R ₂ O and copper oxide (CuO) are in the range of the present embodiment, some change in the black pigment and glass material in the light shielding layer 7 is promoted. And the L ^* value is considered to decrease.

Further, by setting the amount of bismuth oxide (Bi ₂ O ₃ ) contained in the dielectric layer to 15 wt% or less, the dielectric constant of the dielectric layer 8 can be reduced, and the power consumption of the PDP at the time of image display Can be reduced. On the other hand, the amount of bismuth oxide (Bi ₂ O ₃ ) is desirably 5% by weight or more because of the limitation of the temperature condition when firing the dielectric layer 8.

  In addition, the numerical value of the content of each material composition described above has a measurement error of about ± 0.5% by weight in the dielectric material, and a measurement error of about ± 2% by weight in the dielectric layer after firing. To do. The same effects as those of the present invention can be obtained even in a material composition with a content in a numerical range including these errors.

As described above, according to the present invention, it is extremely useful to realize a PDP that suppresses an increase in L ^* value and ensures high visibility.

The perspective view which shows the structure of the plasma display panel in embodiment of this invention Sectional drawing which shows the structure of the front plate of the plasma display panel

Explanation of symbols

2 Front plate 3 Front glass substrate 4 Scan electrode 4a, 5a Transparent electrode 4b, 5b Metal bus electrode 4c, 5c Black electrode 5 Maintenance electrode 6 Display electrode 7 Light shielding layer (black stripe)
8 Dielectric layer 9 Protective layer 10 Back plate 11 Rear glass substrate 12 Address electrode 13 Base dielectric layer 14 Partition 15 Phosphor layer 16 Discharge space

Claims (2)

A front plate having a display electrode, a dielectric layer and a protective layer formed on a glass substrate and a back plate having an electrode, a partition and a phosphor layer formed on the substrate are arranged opposite to each other and sealed around the periphery. A plasma display panel in which a discharge space is formed, wherein the display electrode is mainly composed of silver, and the dielectric layer covers the display electrode, and R ₂ O (R is Li, Na, K, Rb, and Cs). A plasma display panel comprising 5 to 12% by weight of a component represented by at least one selected) and 0.1 to 2% by weight of copper oxide (CuO). _2. The plasma display panel according to claim 1, wherein the dielectric layer mainly contains no lead component and contains 5 wt% to 15 wt% of bismuth oxide (Bi ₂ O ₃ ).

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