WO2011118163A1

WO2011118163A1 - Method of manufacture for plasma display panel

Info

Publication number: WO2011118163A1
Application number: PCT/JP2011/001572
Authority: WO
Inventors: 土居　由佳子; 憲輝前田; 正範三浦; 後藤　真志
Original assignee: パナソニック株式会社
Priority date: 2010-03-26
Filing date: 2011-03-17
Publication date: 2011-09-29
Also published as: WO2011118155A1

Abstract

Disclosed is a method of manufacture for a plasma display panel comprising a sealing step wherein a front panel (2) and a rear panel (10) are disposed facing each other and sealed with a sealing material, and a venting step wherein a gas is vented in an electrical discharge space at a temperature at or above the softening point of the sealing material. The sealing step includes a heating step wherein heat is applied repeatedly and incrementally with a temperature maintained for a time period in a temperature range wherein a gas containing impurities adsorbed by a protective layer (9) detaches therefrom, and a gas influx step wherein a drying gas is flowed into the discharge space (16) such that positive pressure results therein.

Description

Method for manufacturing plasma display panel

The present invention relates to a method for manufacturing a plasma display panel used for a display device or the like.

Plasma display panels (hereinafter referred to as PDPs) are capable of achieving high definition and large screens, so 100-inch class televisions have been commercialized. In recent years, PDP has been applied to high-definition televisions that have more than twice the number of scanning lines compared to the conventional NTSC system. In response to energy problems, efforts to further reduce power consumption and environmental issues There is also a growing demand for PDPs that do not contain lead components in consideration of the above.

The PDP is basically composed of a front plate and a back plate. The front plate is a glass substrate of sodium borosilicate glass produced by the float process, a display electrode composed of a striped transparent electrode and a bus electrode formed on one main surface of the glass substrate, A dielectric layer that covers the display electrode and 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, The phosphor layer is formed between the barrier ribs and emits red, green and blue light.

The front plate and the back plate are hermetically sealed with their electrode forming surfaces facing each other, and a discharge gas of neon (Ne) -xenon (Xe) is 400 Torr to 600 Torr (5.3 ×) in a discharge space partitioned by a partition wall. 10 ⁴ Pa to 8.0 × 10 ⁴ Pa). PDP discharges by selectively applying a video signal voltage to the display electrodes, 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.

In addition, such a PDP driving method includes an initialization period in which wall charges are adjusted so that writing is easy, a writing period in which writing discharge is performed according to an input image signal, and a discharge space in which writing is performed. A driving method having a sustain period in which display is performed by generating a sustain discharge is generally used. A period (subfield) obtained by combining these periods is repeated a plurality of times within a period (one field) corresponding to one frame of an image, thereby performing PDP gradation display.

In such a PDP, the role of the protective layer formed on the dielectric layer of the front plate is to protect the dielectric layer from ion bombardment due to discharge and to emit initial electrons for generating address discharge. Etc. Protecting the dielectric layer from ion bombardment is an important role to prevent an increase in discharge voltage. In addition, the emission of initial electrons for generating an address discharge is an important role for preventing an address discharge error that causes image flickering.

In order to increase the number of initial electrons emitted from the protective layer and reduce image flickering, for example, examples of adding impurities to the MgO protective layer and examples of forming MgO particles on the MgO protective layer are disclosed. (For example, see

Patent Documents

1, 2, 3, 4, 5, etc.).

In recent years, the definition of television has been increased, and the market demands a full HD (high definition) (1920 × 1080 pixels: progressive display) PDP with low cost, low power consumption, and high brightness. Since the electron emission characteristics from the protective layer determine the image quality of the PDP, it is very important to control the electron emission characteristics.

That is, in order to display a high-definition image, the number of pixels to be written increases even though the time of one field is constant. Therefore, in the writing period in the subfield, the pulse applied to the address electrode It is necessary to reduce the width. However, there is a time lag called “discharge delay” from the rise of the voltage pulse to the occurrence of discharge in the discharge space, so if the pulse width is narrowed, the probability that the discharge can be completed within the writing period is low. End up. As a result, lighting failure occurs, and the problem of deterioration in image quality performance such as flickering occurs.

FIG. 12 is a flowchart showing a manufacturing process of a conventional PDP. In FIG. 12, the PDP manufacturing process includes a “front plate creating process” for creating a front plate, a “drying / baking step” for drying and firing the front plate, and a “back plate creating step” for creating the back plate. The glass frit as a sealing member is applied to the outside of the image display area of the back plate, and a “frit coating process” is performed at a temperature of about 350 ° C. in order to remove the resin component and the like, and a “drying and baking process” "The sealing process" that seals the front plate that has finished "the frit application process" and the "exhaust process" that exhausts the gas in the discharge space, and the inside of the vacuum-evacuated panel A “discharge gas supply step” of supplying a discharge gas mainly composed of Ne and Xe. A panel is completed through these steps.

Since the above-mentioned metal oxide that forms the protective layer of the front plate is active, it easily adsorbs impurity gases in the air. For this reason, lighting failure is likely to occur, and the tendency is remarkable as the pressure of the discharge gas and the Xe partial pressure increase.

Therefore, it is necessary to remove the impurity gas by baking the front plate at a high temperature before the “sealing step”. However, when the protective layer is formed of two or more kinds of metal oxides, the impurity gas is adsorbed on the partially complexed metal oxide. This complicates the chemical state of gas adsorption compared to the case where an impurity gas is adsorbed on a single metal oxide. For this reason, it is difficult to remove the impurity gas, and the characteristic improvement is insufficient only by baking at a high temperature. When the front plate was baked in vacuum, improvement in characteristics was observed. However, the vacuum baked resulted in an increase in equipment cost and a reduction in production tact, resulting in lack of mass productivity.

JP 2002-260535 A Japanese Patent Laid-Open No. 11-339665 JP 2006-59779 A JP-A-8-236028 JP-A-10-334809

According to the present invention, a front plate having a dielectric layer and a protective layer covering the dielectric layer, and a back plate having a base dielectric layer and a plurality of barrier ribs formed on the base dielectric layer are opposed to each other. And a method of manufacturing a plasma display panel having a discharge space partitioned by a partition wall between a front plate and a back plate, wherein the front plate and the back plate arranged opposite to each other are sealed with a sealing member. And an exhausting step of exhausting the gas in the discharge space at a temperature equal to or higher than the softening point of the sealing member, and the sealing step includes nitrogen or A temperature raising step in which the temperature is maintained multiple times while the gas containing oxygen is introduced, and a gas inflow step in which the dry gas is introduced so that the discharge space is in a positive pressure state. It is a waste.

This configuration improves the secondary electron emission characteristics in the protective layer. Therefore, even when the Xe gas partial pressure of the discharge gas is increased in order to increase the luminance, it is possible to reduce the discharge starting voltage, and display performance and mass productivity that enable high-intensity and low-voltage driving even in high-definition images. An excellent PDP can be realized.

Also, the reaction between the protective layer and the impurity gas during the panel manufacturing process can be suppressed, and a PDP in which variation in discharge characteristics among discharge cells is suppressed can be realized.

FIG. 1 is a perspective view showing a structure of a PDP according to an embodiment. FIG. 2 is a cross-sectional view of the front plate of the PDP. FIG. 3 is a flowchart showing a manufacturing method of the PDP. FIG. 4 is a view showing an X-ray diffraction result of the underlayer of the PDP. FIG. 5 is a diagram showing an X-ray diffraction result in the base layer having another configuration of the PDP. FIG. 6 is an enlarged view for explaining the aggregated particles of the PDP. FIG. 7 is a diagram showing the relationship between the discharge delay of the PDP and the calcium (Ca) concentration in the protective layer. FIG. 8A is a characteristic diagram showing a desorption gas analysis result with respect to a temperature change of the protective layer of the PDP. FIG. 8B is a characteristic diagram showing the desorption gas analysis result with respect to the processing time of the protective layer of the PDP. FIG. 9A is a characteristic diagram showing a desorption gas analysis result of the front plate when the impurity gas is water in the manufacturing process of the PDP. FIG. 9B is a characteristic diagram showing a desorption gas analysis result of the front plate when the impurity gas is carbon dioxide in the manufacturing process of the PDP. FIG. 10 is a characteristic diagram showing an example of a temperature profile from the sealing step to the discharge gas supply step of the PDP. FIG. 11A is a schematic diagram showing one process from a sealing process to a discharge gas supply process of the PDP. FIG. 11B is a schematic diagram showing one process from a sealing process to a discharge gas supply process of the PDP. FIG. 11C is a schematic diagram showing one process from a sealing process to a discharge gas supply process of the PDP. FIG. 11D is a schematic diagram showing one process from a sealing process to a discharge gas supply process of the PDP. FIG. 11E is a schematic diagram showing one process from a sealing process to a discharge gas supply process of the PDP. FIG. 11F is a schematic diagram showing one process from a sealing process to a discharge gas supply process of the PDP. FIG. 12 is a flowchart showing a conventional method for manufacturing a PDP.

Hereinafter, an embodiment will be described with reference to the drawings.

FIG. 1 is a perspective view showing a structure of a PDP according to an embodiment. The basic structure of the PDP is the same as that of a general AC surface discharge type PDP. As shown in the figure, the PDP 1 has a front plate 2 made of a front glass substrate 3 and the like and a back plate 10 made of a back glass substrate 11 facing each other, and the periphery of the front plate 2 and the back plate 10 is a sealing member. It is comprised by airtightly wearing by. The discharge space 16 inside the sealed PDP 1 is filled with a discharge gas such as Xe and Ne at a pressure of 400 Torr to 600 Torr (5.3 × 10 ⁴ Pa to 8.0 × 10 ⁴ Pa).

On the front glass substrate 3 of the front plate 2, a pair of strip-shaped display electrodes 6 composed of scanning electrodes 4 and sustaining electrodes 5 and light shielding layers 7 which are black stripes are arranged in a plurality of rows in parallel. A dielectric layer 8 is formed so as to cover the display electrodes 6 and the light-shielding layer 7 and retain a charge to act as a capacitor, and a protective layer 9 is further formed thereon.

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 orthogonal 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. In each groove between the barrier ribs 14, a phosphor layer 15 that emits red, green, and blue light by ultraviolet rays is sequentially applied. A discharge space 16 is formed at a position where the scan electrode 4 and the sustain electrode 5 and the address electrode 12 intersect, and the discharge space 16 having the red, green, and blue phosphor layers 15 arranged in the direction of the display electrode 6 is used for color display. It becomes a pixel for.

FIG. 2 is a cross-sectional view of the front plate of the PDP in one embodiment, and FIG. 2 shows FIG. 1 upside down. As shown in the figure, a display electrode 6 including a scanning electrode 4 and a sustain electrode 5 and a light shielding layer 7 are patterned on a front glass substrate 3 manufactured by a float method or the like. Scan electrode 4 and sustain electrode 5 are made of

transparent electrodes

4a and 5a made of indium tin oxide (ITO), tin oxide (SnO ₂ ), etc., and

metal bus electrodes

4b and 5b formed on

transparent electrodes

4a and 5a, respectively. It is comprised by. The

metal bus electrodes

4b and 5b are used for the purpose of imparting conductivity in the longitudinal direction of the

transparent electrodes

4a and 5a, and are formed of a conductive material mainly composed of silver (Ag).

The dielectric layer 8 includes a first dielectric layer 81 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 a first dielectric. The second dielectric layer 82 formed on the layer 81 has at least two layers, and the protective layer 9 is formed on the second dielectric layer 82.

The protective layer 9 includes a base layer 91 formed on the dielectric layer 8 and aggregated particles 92 in which a plurality of magnesium oxide (MgO) crystal particles 92 a are aggregated on the base layer 91. In the protective layer 9, the underlayer 91 is a metal oxide composed of at least two kinds of oxides selected from magnesium oxide (MgO), calcium oxide (CaO), strontium oxide (SrO), and barium oxide (BaO). It is formed by things.

FIG. 3 is a flowchart showing the manufacturing process of the PDP in the present embodiment. As shown in the figure, the PDP manufacturing process includes a “front plate creating process” for creating the front plate 2, a “back plate creating step” for creating the back plate 10, and a sealing member outside the image display area of the back plate 10. A “sealing material application process” in which the resin component and the like are temporarily baked at a temperature of about 350 ° C., and the front panel 2 and the back panel 10 that has completed the “sealing material application process”. “Sealing process” for sealing, “exhaust process” for exhausting the gas in the discharge space 16, and “discharge gas supply process for supplying a discharge gas mainly composed of Ne and Xe into the evacuated panel” Is included. A panel is completed through these steps.

Here, the sealing member is preferably a frit mainly composed of bismuth oxide or vanadium oxide. Examples of the frit mainly composed of bismuth oxide include a Bi ₂ O ₃ —B ₂ O ₃ —RO—MO system (where R is any one of Ba, Sr, Ca, and Mg, and M is Any of Cu, Sb, and Fe)) and a filler made of an oxide such as Al ₂ O ₃ , SiO ₂ , and cordierite can be used. Further, as a frit containing vanadium oxide as a main component, for example, a filler made of an oxide such as Al ₂ O ₃ , SiO ₂ or cordierite is added to a V ₂ O ₅ —BaO—TeO—WO glass material. Things can be used.

First, the “front plate creation process” will be described. On the front glass substrate 3, the scan electrode 4, the sustain electrode 5, and the light shielding layer 7 are formed.

Transparent electrodes

4a and 5a and

metal bus electrodes

4b and 5b constituting scan electrode 4 and sustain electrode 5 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 (Ag) material at a predetermined temperature. Similarly, the light shielding layer 7 is also formed by screen printing a paste containing a black pigment, or by patterning and baking using a photolithography method after forming a black pigment on the entire surface of the glass substrate.

Next, a dielectric paste (dielectric material) layer is formed by applying a dielectric paste on the front glass substrate 3 by a die coating method or the like so as to cover the scanning electrode 4, the sustain electrode 5 and the light shielding layer 7. 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 formed by baking and solidifying the dielectric paste layer to cover 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 base layer 91 is formed on the dielectric layer 8. In the present embodiment, the base layer 91 is formed of a metal oxide composed of at least two oxides selected from magnesium oxide (MgO), calcium oxide (CaO), strontium oxide (SrO), and barium oxide (BaO). It is formed by things.

The underlayer 91 is prepared by mixing pellets of single materials of magnesium oxide (MgO), calcium oxide (CaO), strontium oxide (SrO), and barium oxide (BaO), or by mixing these materials in advance. It is formed by a thin film forming method such as using pellets. As a thin film forming method, a known method such as an electron beam evaporation method, a sputtering method, or an ion plating method can be applied. As an example, 1 Pa is considered as the upper limit of the pressure that can actually be taken in the sputtering method and 0.1 Pa in the electron beam evaporation method, which is an example of the evaporation method. In addition, as an atmosphere during film formation of the underlayer 91, predetermined electron emission can be achieved by adjusting the atmosphere during film formation in a sealed state shut off from the outside in order to prevent moisture adhesion and impurity gas adsorption. A base layer 91 made of a metal oxide having characteristics can be formed.

Next, the agglomerated particles 92 of the magnesium oxide (MgO) crystal particles 92a deposited on the base layer 91 will be described. These crystal particles 92a can be manufactured by any one of the following vapor phase synthesis method or precursor baking method. In the gas phase synthesis method, a magnesium metal material having a purity of 99.9% or more is heated in an atmosphere filled with an inert gas, and a small amount of oxygen is introduced into the atmosphere to directly oxidize magnesium, thereby oxidizing the material. Magnesium (MgO) crystal particles 92a can be produced.

In the precursor firing method, a magnesium oxide (MgO) precursor is uniformly fired at a high temperature of 700 ° C. or higher, and this is gradually cooled to obtain magnesium oxide (MgO) crystal particles 92a. Examples of the precursor include magnesium alkoxide (Mg (OR) ₂ ), magnesium acetylacetone (Mg (C ₅ H ₇ O ₂ ) ₂ ), magnesium hydroxide (Mg (OH) ₂ ), magnesium carbonate (MgCO ₃ ), One or more compounds selected from magnesium chloride (MgCl ₂ ), magnesium sulfate (MgSO ₄ ), magnesium nitrate (Mg (NO ₃ ) ₂ ), and magnesium oxalate (MgC ₂ O ₄ ) can be selected. Depending on the selected compound, it may usually take the form of a hydrate, which may be used.

These compounds are adjusted so that the purity of magnesium oxide (MgO) obtained after firing is 99.95% or more, preferably 99.98% or more. If these compounds contain a certain amount or more of various impurity elements such as alkali metals, B, Si, Fe, and Al, unnecessary interparticle adhesion and sintering occur during heat treatment, and highly crystalline magnesium oxide ( This is because it is difficult to obtain MgO) crystal particles. For this reason, it is necessary to adjust the precursor in advance by removing the impurity element.

The magnesium oxide (MgO) crystal particles 92a obtained by any of the above methods are dispersed in a solvent, and the dispersion is dispersed and dispersed on the surface of the underlayer 91 by spraying, screen printing, electrostatic coating, or the like. Let

Next, magnesium oxide (MgO) crystal particles 92 a are fixed to the surface of the underlayer 91 on the protective layer 9. Through such a series of 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, in the “back plate making process”, 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. A material layer to be a material is formed. Thereafter, the address electrode 12 is formed by firing at a predetermined temperature. Next, a dielectric paste layer is formed on the rear glass substrate 11 on which the address electrodes 12 are formed by applying a dielectric paste so as to cover the address electrodes 12 by a die coating method or the like. Thereafter, the base dielectric layer 13 is formed by firing the dielectric paste layer.

Next, a barrier rib forming paste containing barrier rib material is applied on the underlying dielectric layer 13 and patterned into a predetermined shape to form a barrier rib material layer. Then, the partition 14 is formed by baking at a predetermined temperature. 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. Then, the phosphor layer 15 is formed by applying and baking 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. Through the above steps, the back plate 10 having predetermined components on the back glass substrate 11 is completed.

Here, the first dielectric layer 81 and the second dielectric layer 82 constituting the dielectric layer 8 of the front plate 2 will be described in detail. The dielectric material of the first dielectric layer 81 is composed of the following material composition. That is, 20% by weight to 40% by weight of bismuth oxide (Bi ₂ O ₃ ), 0.5% by weight to 12% of at least one selected from calcium oxide (CaO), strontium oxide (SrO), and barium oxide (BaO). Contains 0.1% by weight to 7% by weight of at least one selected from molybdenum oxide (MoO ₃ ), tungsten oxide (WO ₃ ), cerium oxide (CeO ₂ ), and manganese dioxide (MnO ₂ ). .

In place of molybdenum oxide (MoO ₃ ), tungsten oxide (WO ₃ ), cerium oxide (CeO ₂ ), manganese dioxide (MnO ₂ ), copper oxide (CuO), chromium oxide (Cr ₂ O ₃ ), cobalt oxide At least one selected from (Co ₂ O ₃ ), vanadium oxide (V ₂ O ₇ ), and antimony oxide (Sb ₂ O ₃ ) may be contained in an amount of 0.1 wt% to 7 wt%.

In addition to the above components, zinc oxide (ZnO) is contained in an amount of 0 to 40% by weight, boron oxide (B ₂ O ₃ ) in an amount of 0 to 35% by weight, and silicon oxide (SiO ₂ ) in an amount of 0 to 4% by weight. A material composition that does not contain a lead component, such as 15 wt% and aluminum oxide (Al ₂ O ₃ ) 0 wt% to 10 wt% may be included.

A dielectric material powder is prepared by pulverizing a dielectric material composed of these composition components with a wet jet mill or a ball mill so that the particle diameter becomes 0.5 μm to 2.5 μm. Next, 55 wt% to 70 wt% of the dielectric material powder and 30 wt% to 45 wt% of the binder component are well kneaded with three rolls to paste for the first dielectric layer 81 for die coating or printing. Is made.

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

Next, using this first dielectric layer paste, the front glass substrate 3 is printed by a die coat method or a screen printing method so as to cover the display electrode 6 and dried, and then slightly higher than the softening point of the dielectric material. The first dielectric layer 81 is formed by baking at a temperature of 575 ° C. to 590 ° C.

The dielectric material of the second dielectric layer 82 is composed of the following material composition. That is, bismuth oxide (Bi ₂ O ₃ ) is 11 wt% to 20 wt%, and at least one selected from calcium oxide (CaO), strontium oxide (SrO), and barium oxide (BaO) is 1.6 wt%. It contains ˜21 wt%, and contains 0.1 wt% ˜7 wt% of at least one selected from molybdenum oxide (MoO ₃ ), tungsten oxide (WO ₃ ), and cerium oxide (CeO ₂ ).

Instead of molybdenum oxide (MoO ₃ ), tungsten oxide (WO ₃ ), and cerium oxide (CeO ₂ ), copper oxide (CuO), chromium oxide (Cr ₂ O ₃ ), cobalt oxide (Co ₂ O ₃ ), vanadium oxide At least one selected from (V ₂ O ₇ ), antimony oxide (Sb ₂ O ₃ ), and manganese oxide (MnO ₂ ) may be contained in an amount of 0.1 wt% to 7 wt%. In addition to the above components, zinc oxide (ZnO) is contained in an amount of 0 to 40% by weight, boron oxide (B ₂ O ₃ ) in an amount of 0 to 35% by weight, and silicon oxide (SiO ₂ ) in an amount of 0 to 4% by weight. A material composition that does not contain a lead component, such as 15 wt% and aluminum oxide (Al ₂ O ₃ ) 0 wt% to 10 wt% may be included.

Dielectric material powders having these compositions are pulverized with a wet jet mill or a ball mill so that the particle diameter becomes 0.5 μm to 2.5 μm to produce a dielectric material powder. Next, 55 wt% to 70 wt% of the dielectric material powder and 30 wt% to 45 wt% of the binder component are well kneaded with three rolls to form a second dielectric layer paste for die coating or printing. Make it. The binder component is ethyl cellulose, terpineol containing 1% to 20% by weight of acrylic resin, or butyl carbitol acetate. 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, using this second dielectric layer paste, printing is performed on the first dielectric layer 81 by screen printing or die coating, followed by drying. Thereafter, a temperature slightly higher than the softening point of the dielectric material is 550 ° C. Bake at 590 ° C.

The film thickness of the dielectric layer 8 is preferably set to 41 μm or less in combination with the first dielectric layer 81 and the second dielectric layer 82 in order to ensure visible light transmittance. The first dielectric layer 81 has a bismuth oxide (Bi ₂ O ₃ ) content of the second dielectric layer 82 in order to suppress the reaction of the

metal bus electrodes

4b and 5b with silver (Ag). More than the content of (Bi ₂ O ₃ ), the content is 20 wt% to 40 wt%. Therefore, since the visible light transmittance of the first dielectric layer 81 is lower than the visible light transmittance of the second dielectric layer 82, the film thickness of the first dielectric layer 81 is set to the film thickness of the second dielectric layer 82. It is thinner.

The second dielectric layer 82 is less likely to be colored when the content of bismuth oxide (Bi ₂ O ₃ ) is 11% by weight or less, but is preferable because bubbles are easily generated in the second dielectric layer 82. Absent. Moreover, since it will become easy to color when content rate exceeds 40 weight%, the transmittance | permeability falls. In addition, the smaller the film thickness of the dielectric layer 8, the more remarkable is the effect of improving the luminance and reducing the discharge voltage. Therefore, it is desirable to set the film thickness as thin as possible within the range where the withstand voltage does not decrease. From this point of view, in the present embodiment, the thickness of the dielectric layer 8 is set to 41 μm or less, the first dielectric layer 81 is set to 5 μm to 15 μm, and the second dielectric layer 82 is set to 20 μm to 36 μm.

In the PDP 1 manufactured in this way, even when a silver (Ag) material is used for the display electrode 6, the front glass substrate 3 is less colored (yellowing), and bubbles are generated in the dielectric layer 8. Therefore, the dielectric layer 8 having excellent withstand voltage performance can be realized.

Next, the protective layer 9 of the PDP 1 in this embodiment will be described. In the PDP 1 in the present embodiment, as shown in FIG. 2, the protective layer 9 includes an underlayer 91 formed on the dielectric layer 8 and magnesium oxide (MgO) crystal particles 92 a attached on the underlayer 91. A plurality of aggregated particles 92 are formed. The underlayer 91 is formed of a metal oxide composed of at least two oxides selected from magnesium oxide (MgO), calcium oxide (CaO), strontium oxide (SrO), and barium oxide (BaO). In the X-ray diffraction analysis of the surface of the base layer 91, the metal oxide has a peak between the minimum diffraction angle and the maximum diffraction angle generated from a single oxide constituting the metal oxide having a specific orientation plane. .

That is, the base layer 91 of the protective layer 9 includes at least two metal oxides selected from the group consisting of magnesium oxide, calcium oxide, strontium oxide, and barium oxide, and the specific orientation of the base layer 91 of the protective layer 9 The diffraction angle peak of the X-ray diffraction analysis on the plane is the diffraction angle peak of the X-ray diffraction analysis on the specific orientation plane of one of the two metal oxides included in the underlayer 91 of the protective layer 9; It exists between the diffraction angle peak of the X-ray diffraction analysis in the specific orientation plane of the other metal oxide.

FIG. 4 is a diagram showing an X-ray diffraction result of the base layer constituting the protective layer of the PDP. FIG. 4 also shows the results of X-ray diffraction analysis of magnesium oxide (MgO) alone, calcium oxide (CaO) alone, strontium oxide (SrO) alone, and barium oxide (BaO) alone.

4, the horizontal axis represents the Bragg diffraction angle (2θ), and the vertical axis represents the intensity of the X-ray diffraction wave. The unit of the diffraction angle is shown in degrees when one round is 360 degrees, and the intensity is shown in an arbitrary unit (arbitrary unit). In the figure, the crystal orientation plane which is a specific orientation plane is shown in parentheses. As shown in FIG. 4, in the crystal orientation plane (111), the diffraction angle is 32.2 degrees for calcium oxide (CaO) alone, the diffraction angle is 36.9 degrees for magnesium oxide (MgO) alone, and strontium oxide (SrO) alone. Shows a peak at a diffraction angle of 30.0 degrees, and barium oxide (BaO) alone has a peak at a diffraction angle of 27.9 degrees.

In PDP 1 in the present embodiment, at least two oxides selected from magnesium oxide (MgO), calcium oxide (CaO), strontium oxide (SrO), and barium oxide (BaO) are used as base layer 91 of protective layer 9. It is made of a metal oxide made of a material.

FIG. 4 shows the X-ray diffraction results when the single component constituting the underlayer 91 is two components. That is, the X-ray diffraction result of the base layer 91 formed using magnesium oxide (MgO) and calcium oxide (CaO) alone was formed using point A, magnesium oxide (MgO) and strontium oxide (SrO) alone. The X-ray diffraction result of the underlayer 91 is indicated by point B, and further, the X-ray diffraction result of the underlayer 91 formed using a simple substance of magnesium oxide (MgO) and barium oxide (BaO) is indicated by C point.

That is, the point A is a diffraction angle of 36.9 degrees of the magnesium oxide (MgO) alone, which is the maximum diffraction angle of the single oxide, in the crystal orientation plane (111) as the specific orientation plane, and the oxidation which is the minimum diffraction angle. A peak exists at a diffraction angle of 36.1 degrees, which is between the diffraction angle of 32.2 degrees of calcium (CaO) alone. Similarly, peaks at points B and C exist at 35.7 degrees and 35.4 degrees between the maximum diffraction angle and the minimum diffraction angle, respectively.

Further, FIG. 5 shows the X-ray diffraction result in the case where the single component constituting the base layer 91 is three or more components, as in FIG. That is, FIG. 5 shows the results when magnesium oxide (MgO), calcium oxide (CaO), and strontium oxide (SrO) are used as the single component, point D, magnesium oxide (MgO), calcium oxide (CaO), and oxidation. The results when barium (BaO) is used are indicated by point E, and the results when calcium oxide (CaO), strontium oxide (SrO) and barium oxide (BaO) are used are indicated by point F.

The point D corresponds to the diffraction angle of 36.9 degrees of magnesium oxide (MgO) as the maximum diffraction angle of a single oxide and the strontium oxide as the minimum diffraction angle in (111) of the crystal orientation plane as the specific orientation plane. There is a peak at a diffraction angle of 33.4 degrees, which is between the diffraction angle of 30.0 degrees of (SrO) alone. Similarly, peaks at points E and F exist at 32.8 degrees and 30.2 degrees between the maximum diffraction angle and the minimum diffraction angle, respectively.

Therefore, the base layer 91 of the PDP 1 in this embodiment has a specific orientation plane in the X-ray diffraction analysis of the base layer 91 surface of the metal oxide constituting the base layer 91, whether it is a single component or a three component. A peak exists between the minimum diffraction angle and the maximum diffraction angle of a peak generated from a single oxide constituting the metal oxide.

In the above description, (111) has been described as the crystal orientation plane as the specific orientation plane, but the peak position of the metal oxide is the same as described above even when other crystal orientation planes are targeted.

The depth from the vacuum level of calcium oxide (CaO), strontium oxide (SrO), and barium oxide (BaO) exists in a shallow region as compared with magnesium oxide (MgO). Therefore, when the PDP 1 is driven, when electrons existing in the energy levels of calcium oxide (CaO), strontium oxide (SrO), and barium oxide (BaO) transition to the ground state of the xenon (Xe) ion, Auger It is considered that the number of electrons emitted due to the effect increases as compared with the case of transition from the energy level of magnesium oxide (MgO).

In addition, as described above, the base layer 91 in the present embodiment is configured such that a peak exists between the minimum diffraction angle and the maximum diffraction angle of the peak generated from a single oxide constituting the metal oxide. Yes. As a result of the X-ray diffraction analysis, the metal oxide having the characteristics shown in FIGS. 4 and 5 has its energy level between the single oxides constituting them. Therefore, the energy level of the base layer 91 also exists between the single oxides, and the amount of energy acquired by other electrons due to the Auger effect can be set to a sufficient amount to be released beyond the vacuum level. .

As a result, the base layer 91 can exhibit better secondary electron emission characteristics than the magnesium oxide (MgO) alone, and the discharge sustaining voltage can be reduced. Therefore, in particular, when the partial pressure of xenon (Xe) as the discharge gas is increased in order to increase the luminance, it is possible to reduce the discharge voltage and realize a low-voltage and high-luminance PDP1.

Table 1 shows the structure of the underlying layer 91 as a result of the discharge sustaining voltage when a mixed gas (Xe, 15%) of 450 Torr of xenon (Xe) and neon (Ne) is sealed in the PDP 1 of the present embodiment. The result of PDP1 when changing is shown.

The discharge sustaining voltage in Table 1 is expressed as a relative value when the comparative example is 100. The base layer 91 of sample A is a metal oxide made of magnesium oxide (MgO) and calcium oxide (CaO). The base layer 91 of sample B is a metal oxide made of magnesium oxide (MgO) and strontium oxide (SrO). The underlayer 91 is a metal oxide made of magnesium oxide (MgO) and barium oxide (BaO). The underlayer 91 of the sample D is a metal oxide made of magnesium oxide (MgO), calcium oxide (CaO), and strontium oxide (SrO). The underlayer 91 of sample E is composed of a metal oxide made of magnesium oxide (MgO), calcium oxide (CaO), and barium oxide (BaO). Further, the comparative example shows a case where the base layer 91 is made of magnesium oxide (MgO) alone.

When the partial pressure of the discharge gas xenon (Xe) is increased from 10% to 15%, the luminance increases by about 30%. However, in the comparative example in which the underlying layer 91 is made of magnesium oxide (MgO) alone, the discharge is maintained. The voltage increases about 10%.

On the other hand, in the PDP 1 in the present embodiment, the discharge sustain voltage can be reduced by about 10% to 20% in all of the sample A, the sample B, the sample C, the sample D, and the sample E as compared with the comparative example. Therefore, the discharge start voltage can be set within the normal operation range, and a high-luminance and low-voltage drive PDP 1 can be realized.

Calcium oxide (CaO), strontium oxide (SrO), and barium oxide (BaO) are particularly reactive as a single substance, so that they easily react with impurities such as water and carbon dioxide. As a result, electron emission performance is improved. It tends to decline.

However, by using such a metal oxide structure, the reactivity is suppressed, and a crystal structure with few impurities and oxygen vacancies is formed. As a result, excessive emission of electrons during driving of the PDP 1 is suppressed, and in addition to the compatibility between low voltage driving and secondary electron emission performance, the effect of moderate electron retention characteristics is also exhibited. This charge retention characteristic is particularly effective for retaining wall charges stored during the initialization period and preventing write defects during the write period to perform reliable write discharge.

Next, the agglomerated particles 92 provided on the underlayer 91 in the present embodiment and agglomerated a plurality of magnesium oxide (MgO) crystal particles 92a will be described in detail. Aggregated particles 92 of magnesium oxide (MgO) have been confirmed to have an effect of mainly suppressing “discharge delay” in write discharge and improving temperature dependency of “discharge delay”. Therefore, in the present embodiment, the aggregated particles 92 are arranged as an initial electron supply unit required at the time of rising of the discharge pulse by utilizing the property that the advanced initial electron emission characteristics are superior to those of the base layer 91.

The “discharge delay” is considered to be mainly caused by a shortage of the amount of initial electrons that are triggered from the surface of the underlayer 91 into the discharge space 16 at the start of discharge. Therefore, in order to contribute to the stable supply of initial electrons to the discharge space 16, the aggregated particles 92 of magnesium oxide (MgO) are dispersedly arranged on the surface of the underlayer 91. As a result, abundant electrons are present in the discharge space 16 at the rise of the discharge pulse, and the discharge delay can be eliminated. Therefore, such initial electron emission characteristics enable high-speed driving with good discharge response even when the PDP 1 has a high definition. In the configuration in which the metal oxide aggregated particles 92 are disposed on the surface of the underlayer 91, in addition to the effect of mainly suppressing the “discharge delay” in the write discharge, the effect of improving the temperature dependency of the “discharge delay” is also achieved. can get.

As described above, the PDP 1 according to the present embodiment includes the base layer 91 capable of achieving both low voltage driving and charge retention, and the magnesium oxide (MgO) aggregated particles 92 effective in preventing discharge delay. Thus, as a whole PDP 1, high-definition PDP 1 can be driven at a high voltage with a low voltage, and high-quality image display performance with reduced lighting defects can be realized.

In the present embodiment, agglomerated particles 92 in which several crystal particles 92a are agglomerated are dispersed on base layer 91, and a plurality of particles are adhered so as to be distributed almost uniformly over the entire surface. FIG. 6 is an enlarged view for explaining the agglomerated particles 92.

The agglomerated particles 92 are in a state where crystal particles 92a having a predetermined primary particle diameter are aggregated or necked as shown in the figure. In other words, it is not a solid that has a large binding force, but a plurality of primary particles that are aggregated by static electricity or van der Waals force. Some or all of them are bonded to such a degree that they become primary particles. The particle size of the agglomerated particles 92 is about 1 μm to several μm, and the crystal particles 92 a preferably have a polyhedral shape having seven or more surfaces such as a tetrahedron and a dodecahedron.

Further, the particle size of the primary particles of the crystal particles 92a can be controlled by the generation conditions of the crystal particles 92a. For example, when an MgO precursor such as magnesium carbonate or magnesium hydroxide is calcined and produced, the particle size can be controlled by controlling the calcining temperature and the calcining atmosphere. Generally, the firing temperature can be selected in the range of 700 ° C. to 1500 ° C., but by setting the firing temperature to a relatively high 1000 ° C. or higher, the particle size can be controlled to about 0.3 to 2 μm. is there. Furthermore, by heating the MgO precursor as the crystal particles 92a, a plurality of primary particles are bonded together by a phenomenon called agglomeration or necking in the production process to obtain agglomerated particles 92.

FIG. 7 is a diagram showing the relationship between the discharge delay of the PDP and the calcium (Ca) concentration in the protective layer in the present embodiment. Specifically, the relationship between the discharge delay and the calcium (Ca) concentration in the protective layer 9 in the case of using the base layer 91 composed of a metal oxide of magnesium oxide (MgO) and calcium oxide (CaO) is shown. ing. The base layer 91 is composed of a metal oxide composed of magnesium oxide (MgO) and calcium oxide (CaO), and the metal oxide has a peak of magnesium oxide (MgO) in the X-ray diffraction analysis on the surface of the base layer 91. A peak exists between the diffraction angle at which the peak is generated and the diffraction angle at which the peak of calcium oxide (CaO) is generated. FIG. 7 shows the case where only the underlayer 91 is used as the protective layer 9 and the case where the aggregated particles 92 are arranged on the underlayer 91, and the discharge delay is caused by calcium (Ca) contained in the underlayer 91. The case where it is not done is shown as a standard.

The electron emission performance is a numerical value indicating that the larger the electron emission amount, the greater the amount of electron emission. The initial electron emission amount can be measured by a method of measuring the amount of electron current emitted from the surface by irradiating the surface with ions or an electron beam. However, the evaluation of the surface of the front plate 2 of the PDP 1 can be performed nondestructively. With difficulty. Therefore, evaluation was performed using the method described in JP-A-2007-48733. That is, among the delay times at the time of discharge, a numerical value called a statistical delay time, which is a measure of the likelihood of occurrence of discharge, is measured, and the reciprocal is integrated to obtain a numerical value linearly corresponding to the initial electron emission amount. The delay time at the time of discharge means a discharge delay time in which the discharge is delayed from the rising edge of the pulse. It is considered that the discharge delay is mainly caused by the fact that initial electrons that become a trigger when the discharge is started are not easily released from the surface of the protective layer 9 into the discharge space 16.

As apparent from FIG. 7, in the case of only the underlayer 91 and in the case where the aggregated particles 92 are arranged on the underlayer 91, the discharge delay increases as the calcium (Ca) concentration increases in the case of only the underlayer 91. On the other hand, it can be seen that by disposing the agglomerated particles 92 on the base layer 91, the discharge delay can be significantly reduced, and the discharge delay hardly increases even when the calcium (Ca) concentration is increased.

In the above description, the magnesium oxide (MgO) particles are used as the crystal particles 92a of the agglomerated particles 92. The same effect can be obtained even if the crystal particles 92a are used, and the particle type is not limited to magnesium oxide (MgO).

In the present embodiment, when the protective layer 9 is formed of at least two kinds of metal oxides selected from magnesium oxide, calcium oxide, strontium oxide, and barium oxide as described above, a plurality of metal oxides are included. Therefore, since the desorption temperatures of the impurity gases in the respective metal oxides are different, the desorption temperature range of the impurity gases extends over a wide range. For this reason, the discharge characteristics deteriorate due to adsorption of impurity gases such as water and carbon dioxide due to the state left before the “sealing process”, and the discharge characteristics vary from discharge cell to discharge cell, resulting in reduced mass production stability. It's easy to do.

Therefore, in the present embodiment, as shown in FIG. 3, a temperature raising step in which the temperature is maintained in a temperature range where the impurity gas adsorbed on the protective layer 9 is desorbed and the temperature is raised stepwise is provided. A sealing process including a gas inflow process for allowing a dry gas to flow into the discharge space 16 through a through-hole opened in the discharge space 16 and a temperature equal to or higher than the softening point of the sealing member. An exhaust process for exhausting the gas inside. By this step, the impurity gas adsorbed on the protective layer 9 and the residual components of the solvent used for forming the aggregated particles 92 and the impurity gas can be removed. That is, the impurity gas in the discharge space 16 can be reduced, and deterioration and variation in discharge characteristics can be suppressed.

Here, the reason why the temperature is raised stepwise in the temperature region where the impurity gas adsorbed on the protective layer 9 is desorbed is that the impurity gas adsorbed on the protective layer 9 and the residual components of the solvent used for forming the aggregated particles 92 are This is for efficient removal in a short time.

When there are a plurality of metal oxides constituting the protective layer 9, the desorption temperatures of the impurity gases adsorbed on each metal oxide are different, so that gas desorption occurs in a plurality of temperature regions, resulting in impurities in a wide temperature region. The gas will continue to desorb. At this time, if baking is performed at the highest desorption temperature, the impurity gas cannot be sufficiently decomposed into the protective layer 9. Accordingly, the temperature is raised stepwise at the temperature at which each impurity gas is desorbed, and the temperature is maintained until the desorption of the impurity gas is completed in each temperature region, whereby a clean protective layer 9 can be obtained. Moreover, the temperature to hold | maintain is higher than the temperature hold | maintained before that, It is desirable to heat up in steps and to bake. Furthermore, it is desirable that the temperature held first is 300 ° C. or higher.

The reason why the dry gas is allowed to flow during the above temperature rise is that the impurity gas once desorbed from the protective layer 9 and the back plate 10 due to the temperature rise in the panel is not again adsorbed to the protective layer 9. It is something that is physically extruded from. This is because moisture is reduced in a high-temperature firing atmosphere, so that carbon dioxide is particularly easily resorbed among impurity gases, and a part of the metal oxide constituting the protective layer 9 is carbonated. As a result, due to the temperature distribution in the baking furnace and the concentration distribution of the impurity gas, the resorption of the impurity gas becomes uneven within the substrate surface, which is one of the factors that cause variations in discharge characteristics.

In the temperature raising step, if the temperature is maintained in a temperature range where the impurity gas adsorbed on the protective layer 9 is desorbed and the temperature is maintained while the nitrogen gas containing nitrogen or oxygen is introduced, the temperature is raised stepwise. The re-adsorption of the impurity gas once removed can be suppressed.

The gas to be introduced is preferably dry gas, and nitrogen gas is relatively inexpensive and desirable. In addition, when the hydrocarbon gas is included in the impurity gas, a nitrogen gas containing oxygen may be introduced to promote thermal decomposition of the hydrocarbon gas. Further, an inert gas such as argon may be included.

In maintaining the temperature stepwise, the initial holding (lower limit) temperature depends on the boiling point of the organic solvent used, but is preferably at least 200 ° C. or more, more preferably 300 ° C. or more for thermal decomposition. . The upper limit temperature may be equal to or lower than the softening point of the dielectric layer material (approximately 500 ° C. to 600 ° C.).

In order to determine the region where the temperature is maintained, the desorption temperature of the impurity gas from the protective layer 9 may be confirmed. For example, the front plate 2 before firing can be cut into small pieces, and the type and amount of desorption gas when heated in vacuum using a temperature programmed desorption analysis method (TDS analysis) can be confirmed.

FIG. 8A is a characteristic diagram showing the desorption gas analysis result with respect to the temperature change of the protective layer, and FIG. 8B is a characteristic diagram showing the desorption gas analysis result with respect to the processing time of the protective layer. Specifically, using a TDS analyzer EMD-WA1000S / W manufactured by Electronic Science, the aggregated particles 92 are formed on the sample A described above (the base layer 91 is a metal oxide made of magnesium oxide (MgO) and calcium oxide (CaO)). And the solvent is removed by vacuum drying, and then the front plate 2 from which the solvent has been removed by baking at 320 ° C. in the air is heated at 10 ° C./min and held at 500 ° C. for 30 min. Indicates the type of gas and the amount of desorption. Here, desorption spectra with respect to temperature and treatment time are shown for water having a mass number of 18 and carbon dioxide having a mass number of 44 as main impurity gases.

Since the solvent used to form the agglomerated particles 92 is substantially removed by baking at 320 ° C. in the atmosphere, the sample A is generated from two types of metal oxides in the desorbed gas as shown in FIGS. 8A and 8B. I understand that. As shown in FIG. 8A and FIG. 8B, the desorption of water is divided into three stages of temperature ranges of (1) 380 ° C. to 400 ° C., (2) 420 to 450 ° C., and (3) 480 to 500 ° C. Yes, the desorption of carbon dioxide is in the temperature range of (1) and (3), and the desorption time should be several minutes or more, and the gas desorption is almost completed after holding for the final 30 minutes. ing. The existence of the plurality of desorption temperature regions is considered to be because the protective layer 9 is made of a plurality of metal oxides.

Therefore, the results of examining the firing conditions of the front plate 2 using the front plate 2 in which the protective layer 9 is made of the sample A are shown in FIGS. 9A and 9B.

FIG. 9A is a characteristic diagram showing the desorption gas analysis result of the front plate when the impurity gas is water, and FIG. 9B is a characteristic diagram showing the desorption gas analysis result of the front plate when the impurity gas is carbon dioxide. It is.

In FIG. 9A and FIG. 9B, the “step firing” of the conditions 2), 3) and 4) is firing under the conditions of holding the temperature at 380 ° C., 420 ° C., 450 ° C. and 480 ° C. for 10 minutes each , condition 2), 5), the N ₂ as an atmosphere gas during firing has 1L / min flowing, condition 3) is flowed in 20% O ₂ added to the N _2. 5) and 6) are TDS analysis results after firing at 500 ° C. In all cases, the temperature was raised at 10 ° C./min.

9) As shown in FIGS. 9A and 9B, 6) After vacuum baking at 500 ° C., there is little desorption of carbon dioxide, and much water is desorbed at 200 to 300 ° C. The gas desorbed at a temperature lower than the firing temperature is considered to be a gas that has been re-adsorbed when the substrate is taken out into the atmosphere after firing, and the fact that this amount is large indicates that the protective layer 9 has been cleaned accordingly. is there. As in the condition 6), the conditions 2) and 3) in which the gas was introduced in the “step calcination” were the same as in the condition 6), and the desorption peak of resorbed water was observed as in the condition 6). It is considered that the cleaning is almost equivalent to the vacuum firing.

On the other hand, in the same “step calcination”, the condition 4) in which no gas flows in is that there is almost no water, the carbon dioxide desorption peak is 500 ° C. or higher, and the carbonation of the metal oxide is remarkable. found. In addition, according to “simple temperature firing” instead of “step firing” in condition 5), the amount of carbon dioxide is small, but the desorption of water is also small. This indicates that the water has not been cleaned enough to re-adsorb.

Next, the sealing process in the present embodiment will be described with reference to FIGS.

FIG. 10 shows an example of a temperature profile from the sealing step to the discharge gas supply step in the present embodiment. 11A to 11F are schematic views showing one process from the sealing process to the discharge gas supply process in the present embodiment. 11A to 11F show the gas inside the panel and the flow thereof in the period 1 to the period 5 in FIG. 10, respectively.

As shown in FIG. 10, the process from the sealing process to the discharge gas supply process is divided into the following five periods from the viewpoint of temperature. That is, a period for raising from the room temperature to the softening point (period 1), a period for raising from the softening point to the sealing temperature (period 2), a period for holding for a certain time at a temperature equal to or higher than the sealing temperature, and a period for lowering to the softening point ( Period 3) (above, sealing process), a period during which the temperature is held for a certain period of time near or slightly below the softening point temperature and then decreased to room temperature (period 4: exhausting process), and a period after the temperature has decreased to room temperature (Period 5: discharge gas supply step).

Here, the softening point refers to the temperature at which the glass frit 21 softens. For example, the softening point of the glass frit used in this embodiment is about 430 ° C. The sealing temperature is a temperature at which the front plate 2 and the back plate 10 are sealed by a frit as a sealing member. For example, the sealing temperature in the present embodiment is about 490 ° C.

11A to 11F, reference numeral 21 denotes a glass frit which is a sealing member applied to the peripheral portion of the

back plate

10, and 22a and 22b are through holes provided in the back glass substrate 11 of the back plate 10, and the through

holes

22a, 22 b is provided on the back glass substrate 11 so as to open to the discharge space 16. 23 to 28 are valves, and 29 is a gas relief valve.

First, the front plate 2 and the rear plate 10 are positioned and overlapped so that the display electrode 6 and the address electrode 12 are orthogonally opposed to each other, and then the valve 23 and the valve 24 are opened as shown in FIG. 11A. The heater is turned on and the temperature inside the heating furnace is raised to the softening point temperature of the sealing glass frit 21 while flowing the dry gas into the panel from both the through hole 22a and the through hole 22b.

At this time, as shown by the symbol A, the dry gas that flows into the panel flows into the outside of the panel through the gap between the front plate 2 and the glass frit 21 formed on the back plate 10. . For example, in this embodiment, dry nitrogen gas having a dew point of −45 ° C. or lower is used as the dry gas, and the flow rate thereof is approximately 2 L / min (period 1).

Next, when the temperature inside the heating furnace becomes equal to or higher than the softening point temperature of the glass frit 21, as shown in FIG. 11B, the valve 24 is closed and the valve 23 is adjusted so that the flow rate of the dry nitrogen gas is less than half of the period 1. To do. Then, the gas relief valve 29 is opened, and the temperature inside the heating furnace is raised to the sealing temperature so that the pressure inside the panel becomes slightly positive than the pressure inside the heating furnace for sealing and discharging (period). 2).

Next, when the temperature inside the heating furnace reaches a temperature equal to or higher than the sealing temperature, the glass frit 21 is melted, and the front plate 2 and the rear plate 10 are sealed, as shown in FIG. The exhaust device is operated, and the valve 25 is adjusted to exhaust. In this way, dry nitrogen gas is allowed to flow through the panel at a rate of about 13 cc / min from the through hole 22a toward the through hole 22b while keeping the pressure inside the panel at a slightly negative pressure, for example, 8.0 × 10 4 Pa. During this time, the heater is controlled to keep the temperature inside the heating furnace at a temperature equal to or higher than the sealing temperature for about 30 minutes. In addition, what is necessary is just to set the time which flows dry nitrogen gas inside a panel toward the through-hole 22b from the through-hole 22a according to specifications, such as a magnitude | size of a panel.

Next, as shown in FIG. 11D, the

valves

23 and 25 are closed, the valve 26 is opened, the gas relief valve 29 is opened, and the valve 24 is adjusted to maintain the internal pressure of the panel at a slightly negative pressure. Causes a dry nitrogen gas to flow from the through hole 22b toward the through hole 22a. In this way, the flow of the dry nitrogen gas in the panel is changed to the direction opposite to the above, and the dry nitrogen gas continues to flow inside the panel while keeping the pressure inside the panel slightly negative.

The time for flowing the dry nitrogen gas into the panel from the through hole 22b toward the through hole 22a is also set according to the specifications of the panel, but in order to equalize the flow rate of the dry nitrogen gas to the panel, the through hole 22b is changed from the through hole 22a to the through hole 22b. It is desirable to set the time equal to the time for flowing the dry nitrogen gas toward

During this time, the heater is controlled to keep the temperature inside the heating furnace at a temperature equal to or higher than the sealing temperature for about 15 minutes or longer. During this time, the molten glass frit 21 flows slightly and the pressure inside the panel is kept at a slightly negative pressure, so that the front plate 2 and the back plate 10 are sealed.

After that, the heater is turned off and the temperature of the heating furnace is lowered to a temperature below the softening point (period 3).

The exhaust process is a process of exhausting the gas inside the panel. When the temperature inside the heating furnace 52 becomes lower than the softening point temperature, as shown in FIG. 11E, the valve 24 is closed, the valve 26 and the valve 25 are opened, and the inside of the panel is passed through the glass tube from the two through

holes

22a and 22b. Exhaust. Then, the exhaust is continuously performed while maintaining the temperature inside the heating furnace for a predetermined time by controlling the heater.

After that, the heater is turned off and the temperature inside the heating furnace is lowered to room temperature. During this time, exhaustion is continued (period 4).

The discharge gas supply step is a step of supplying a discharge gas mainly composed of Ne and Xe into the evacuated panel. After the temperature inside the heating furnace has dropped to room temperature, as shown in FIG. 11F, the

valves

26 and 25 are closed, the

valves

27 and 28 are opened, and the discharge gas is supplied to a predetermined pressure through the two through

holes

22a and 22b. Supply to be.

In the present embodiment, the discharge gas is, for example, a mixed gas of Xe: 10% and Ne: 90%, and the predetermined atmospheric pressure is 60 kPa. However, the discharge gas is not limited to this, and may be, for example, a gas of Xe: 100%.

Thereafter, the

glass tubes

43 and 44 are heat-sealed (period 5). As described above, the front plate 2 and the back plate 10 are bonded together, and the discharge gas is filled between them to complete the panel.

In addition, based on the results of FIGS. 9A and 9B, a panel was prepared by changing the temperature rise / gas inflow conditions for raising the temperature to the softening temperature of the glass frit 21 in the sealing step. Specifically, using the front plate 2 having the protective layer 9 made of Sample A, a panel was prepared by raising the temperature and flowing in gas under the conditions 2) to 6) shown in FIGS. 9A and 9B. As a result, in conditions 2) and 3), the conditions 6) of 500 ° C. vacuum and 380 ° C., 420 ° C., 450 ° C., and 480 ° C. were maintained for 10 minutes each and the temperature was raised stepwise to flow in gas. The discharge voltage of the panel could be further reduced by about 5% to 10% compared to the present embodiment. On the other hand, under condition 4) where the temperature was raised stepwise without gas inflow (atmosphere), the voltage increased by about 7% compared to the present embodiment. This is presumably because, under condition 4), the amount of carbon dioxide remaining in the panel is large, so that the electron emission characteristics of the protective layer 9 are lowered and the discharge voltage is increased.

As described above, the present invention is useful in realizing a high-quality display performance and a low power consumption PDP.

1 PDP
DESCRIPTION OF SYMBOLS 2 Front plate 3 Front glass substrate 4

Scan electrode

4a, 5a

Transparent electrode

4b, 5b Metal bus electrode 5 Sustain electrode 6 Display electrode 7 Light-shielding layer 8 Dielectric layer 9 Protective layer 10 Back plate 11 Back glass substrate 12 Address electrode 13 Base dielectric Body layer 14 Partition 15 Phosphor layer 16 Discharge space 21

Glass frit

22a, 22b Through-hole 81 First dielectric layer 82 Second dielectric layer 91 Underlayer 92 Aggregated particle 92a Crystal particle

Claims

A front plate having a dielectric layer and a protective layer covering the dielectric layer;
A back plate having a base dielectric layer and a plurality of barrier ribs formed on the base dielectric layer is disposed opposite to each other, and a discharge space partitioned by the barrier ribs is provided between the front plate and the back plate. A method of manufacturing a plasma display panel,
A sealing step of sealing the front plate and the back plate arranged opposite to each other with a sealing member;
An exhaust step of exhausting the gas in the discharge space at a temperature equal to or higher than the softening point of the sealing member;
The sealing step includes
A temperature raising step for gradually raising the temperature by providing a plurality of periods of holding the temperature while flowing a gas containing nitrogen or oxygen in a temperature region where the impurity gas adsorbed on the protective layer is desorbed;
A method for manufacturing a plasma display panel, comprising: a gas inflow step for allowing a dry gas to flow in such a manner that the discharge space is in a positive pressure state.
2. The plasma display panel manufacturing method according to claim 1, wherein in the gas inflow step, the period of time of holding at 300 ° C. or more is provided a plurality of times and the temperature is increased stepwise, and the holding time of one step is set to several minutes to 30 minutes. Method.
2. The plasma display panel according to claim 1, wherein, in the gas inflow step, the dry gas is caused to flow so that the dry gas leaks from between the front plate and the back plate below the softening point of the sealing member. Manufacturing method.
The protective layer includes at least two metal oxides selected from the group consisting of magnesium oxide, calcium oxide, strontium oxide, and barium oxide,
The diffraction angle peak of the X-ray diffraction analysis on the specific orientation plane of the protective layer shows the X-ray diffraction analysis on the specific orientation plane of one of the two metal oxides included in the protective layer. The method for producing a plasma display panel according to claim 1, wherein the method is between the folding angle peak and a diffraction angle peak of X-ray diffraction analysis in a specific orientation plane of the other metal oxide.