JP3363141B2 - Display panel and manufacturing method thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display panel used for displaying images in computers, televisions and the like, and more particularly to a display panel having a silver electrode formed on the panel surface and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, in color display devices used for image display of computers and televisions, field emission display panels and plasma display panels (Plasma Display Panels,
It is called "PDP". ) And other display panels are drawing attention as color display devices that can realize large and thin panels. Especially, PDPs have excellent characteristics such as high-speed response and a wide viewing angle. Research institutes are actively developing for its popularization.

In such a PDP, a front glass substrate and a rear glass substrate are provided so as to face each other with a gap material interposed therebetween, and a line is provided on the surface of the front glass substrate facing the back glass substrate. A plurality of display electrodes having a rectangular shape are formed, and a dielectric layer is coated so as to cover the electrodes. In a general PDP, a glass plate made of a sodium borosilicate glass material is used as a front glass substrate and a Cr—Cu—Cr electrode is also used as a display electrode, but a silver electrode that can be formed relatively easily is used. It is used.

The silver electrode can be formed by a thin film method, but a thick film method which can be formed relatively inexpensively has also been used. In this thick film method, for example, a silver paste containing silver particles, a glass frit, a resin, a solvent or the like is applied onto a front glass substrate by a screen printing method, or a film containing silver particles, a glass frit, a resin or the like is applied. First, the thick silver film is patterned into an electrode shape by sticking it by a laminating method. After this patterning, in order to decompose and remove the resin contained in the paste or film and fuse the silver particles and the glass frit,
Baking is performed at a temperature of 500 ° C. or higher. By this firing,
The silver particles are fused and the conductivity thereof is improved, and at the same time, the glass frit is fused and the silver particles are fixed to the front glass substrate.

After the firing, in order to form the dielectric layer,
A paste prepared by mixing a powder of low melting point lead glass or the like, a resin, and a solvent is applied by a screen printing method or a laminating method so as to coat the silver electrode, and the solvent is dried.
Baking is performed at a temperature of 00 ° C. or higher. As a result, the resin in the paste is decomposed and removed, and the low melting point lead glass is fused to form a dielectric layer. The rear glass substrate also has electrodes and dielectric layers similar to those on the front glass substrate, and these are formed by the same method as described above.

[0006]

By the way, in a PDP having a silver electrode, silver is ionized during each of the above firings and sodium contained in the glass substrate (usually 2.5 to 1).
5% by weight) is easily diffused inside the glass substrate by a reaction such as ion exchange with an ionized substance.
It is considered that the diffusion of silver proceeds in proportion to the temperature and time during firing, but the silver diffused by this is reduced inside the glass substrate to form a silver colloid, which tends to yellow the glass. In particular, when this yellowing occurs on the front glass substrate, the color temperature is lowered when the PDP is driven, and the image quality of the PDP is likely to be lowered.

In order to reduce the yellowing, it is possible to suppress the diffusion of silver ions by lowering the firing temperature. Regarding the firing temperature, the decomposition start temperature of the resin, the electrode and the dielectric layer are constituted. It is difficult to lower the temperature because it depends on the softening point of the material.
On the other hand, it is possible to reduce the diffusion of silver ions by shortening the firing time, but simply shortening the firing time will leave resin on the electrodes or dielectric layer, or melt the electrodes or dielectric layer. Adhesion may be insufficient, and the conductivity of the electrodes and the insulation of the dielectric layer may be reduced.

Such a phenomenon may occur not only in the PDP but also in a display panel such as a field emission display panel in which a thick film silver electrode is formed on the glass substrate, and the yellow color of the glass substrate of the display panel. There is a demand for a technology that suppresses deterioration.
In view of the above problems, it is an object of the present invention to provide a display panel in which yellowing of a glass substrate is suppressed and a method for manufacturing the display panel as compared with the conventional one.

[0009]

In order to achieve the above object, a display panel according to the present invention is formed so as to cover a plurality of electrodes arranged in a row on one main surface of a substrate. A first panel having a dielectric layer and a second panel arranged in parallel with each other with a partition interposed therebetween, wherein the first panel has glass as a substrate composition and Having silver in the composition of the electrodes,
5 from the interface between the main surface of the electrode and the dielectric layer in the dielectric layer
The concentration of silver diffused in a 5 μm diameter region centered at a point separated by μm, and the concentration of silver diffused in a 5 μm region centered at a point separated by 7.5 μm from the interface between the electrode and the substrate in the substrate. Is characterized by being 0.5 or less.

According to such a display panel,
Since the diffusion of silver into the dielectric layer is small, the dielectric breakdown of the dielectric layer is suppressed, and the diffusion of silver into the substrate is considered to be small, so that the yellowing of the substrate is reduced. Further, when the first panel is the front panel, it is possible to suppress a decrease in color temperature in the display panel.

Further, in order to suppress the yellowing of the front panel, the silver concentration in a 5 μm diameter region centered at a point 7.5 μm away from the interface between the electrode and the substrate in the substrate is 0.8 wt% or less. It is preferable that further,
The front panel has a diameter of 5 μm centered at a point 5 μm away from the interface between the main electrode surface and the dielectric layer in the dielectric layer.
The silver concentration in the m region is preferably 0.4 wt% or less.

A display panel according to the present invention includes a first panel having a plurality of electrodes arranged in a row on one main surface of a substrate and a dielectric layer formed so as to cover the plurality of electrodes. And the second panel is a display panel that is disposed in parallel and opposite to each other via a partition wall.
The panel has glass and 2.5 wt% or more of sodium in the composition of the substrate and silver in the composition of the electrode, and has a diameter of 5 μm centered at a point 7.5 μm away from the interface between the electrode and the substrate in the substrate. It is characterized in that the sodium concentration in the region is 90% or more of the sodium concentration in the 5 μm diameter region on the main surface opposite to the main surface on which the electrodes are formed.

It is considered that silver undergoes ion exchange with sodium contained in a substrate having a glass composition, and if a large amount of sodium remains in the substrate as described above, the diffusion of silver into the dielectric layer is small. Therefore, the dielectric breakdown of the dielectric layer is suppressed, the diffusion of silver into the substrate is small, and the yellowing of the substrate is reduced. Here, the first panel has a sodium concentration of 0.25 wt% in a 5 μm diameter region centered on a point 3 μm away from the side surface of the electrode in the substrate and 3 μm away from the interface between the electrode and the substrate.
By making the following, yellowing of the substrate can be suppressed.

The concrete shape of the panel is the first
The shape in which the substrate of the panel is in direct contact with the electrodes arranged in line on the substrate in the display area of the display panel can be mentioned. Further, a method of manufacturing a display panel according to the present invention is a method of manufacturing a display panel, which includes a panel forming step of forming a silver electrode on a substrate and forming a dielectric layer so as to cover the silver electrode. The forming step includes a first step of forming a pattern layer containing silver, a first resin and a first glass on the substrate, and a second step of covering the pattern layer formed in the first step. Of the resin and the second glass, and a third step of co-firing the pattern layer and the coating layer, the third step comprising the pattern layer and the coating. A first step of raising the temperature to a temperature above the decomposition start temperature of the first and second resins contained in the layer; and maintaining the temperature range above the softening point of the first glass but below the softening point of the second glass. Second step And the flop, the second
And a third step of raising the temperature to a temperature equal to or higher than the softening point of the glass.

In the third step of performing the simultaneous firing, the pattern layer and the coating layer are simultaneously fired, so that the diffusion of silver into the substrate and the coating layer is suppressed. Further, according to the above manufacturing method, the gas generated from the first dielectric glass that is softened in the second step is discharged through the layer in which the unsoftened second dielectric glass is laminated, and then the third gas is generated. Since the second dielectric glass is softened in the step, bubbles are not formed in the first dielectric glass, and the silver electrode can be densely formed.

Further, in the second step, the softening point of the first glass or more and the softening point of the second glass are set by providing a period in which the rate of temperature increase is slower than the rate of temperature increase in the first step. You may make it maintain temperature in the range below. Here, the third step is performed under a reduced pressure atmosphere, a dry gas atmosphere, or an oxidizing gas atmosphere to accelerate the burnout of the resin, or is performed under a reducing gas atmosphere to suppress the oxidation of silver. You may do so.

The method of manufacturing a display panel according to the present invention further includes a front panel forming step of forming a silver electrode on a front glass substrate and forming a dielectric layer so as to cover the silver electrode. In the front panel forming step, a first step of forming a pattern layer containing silver, a first resin, and a first glass on a front glass substrate, and a pattern formed in the first step. A second step of forming a coating layer containing a second resin and a second glass so as to cover the layer, and a third step of co-firing the pattern layer and the coating layer. To do.

According to such a method, the baking time can be shortened by simultaneously baking the front panel as compared with the conventional method, so that the diffusion of silver into the substrate can be suppressed and the conventional method can be achieved. A display panel having a higher color temperature can be manufactured.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a case where the present invention is applied to a PDP will be described as an example of a display panel according to the present invention. [First Embodiment] A first embodiment of a PDP according to the present invention will be described with reference to the drawings.

<Overall Structure of PDP> FIG. 1 is a sectional perspective view of a part of the display area of the PDP according to the present invention.
FIG. 2 is a sectional view taken along the yz axis on the address electrode 17 of the PDP in FIG. The structure of the PDP will be described with reference to both figures. As shown in FIG. 1, the PDP is configured by arranging a front panel 10 and a rear panel 20 so as to face each other.

The front panel 10 includes a front glass substrate 11,
The display electrodes 13 and 14, the dielectric layer 15, and the protective layer 16 are provided, and a plurality of pairs of display electrodes 13 and 14 are alternately arranged on the facing surface of the front glass substrate 11, and as shown in FIG. The dielectric layer 15 and the protective layer 16 are sequentially coated so as to cover the surface of each electrode. The front glass substrate 11 is a flat substrate made of sodium borosilicate glass material, and its composition is sodium (Na).
2.5 wt% is included. The sodium content is not particularly limited, but is generally 15 wt%
Those containing a certain amount are commercially available, and the higher the content, the cheaper the cost is, which is preferable in terms of cost.

The display electrodes 13 and 14 are both display electrodes containing silver as a main component (hereinafter, "main component" means a composition in which the ratio of the weight to the total weight is 50 wt% or more). Is. The dielectric layer 15 includes the display electrodes 13 and 1
4 is formed so as to cover 4, for example, a lead oxide-based glass made of a mixture of lead oxide, boron oxide, silicon oxide, and aluminum oxide, and a mixture of bismuth oxide, zinc oxide, boron oxide, silicon oxide, and calcium oxide. It is composed of a glass component such as bismuth oxide based glass, and has a function of insulating the display electrodes 13 and 14.

The protective layer 16 is formed so as to cover the surface of the dielectric layer 15, and is a layer made of magnesium oxide (MgO) or the like. Since the display electrodes 13 and 14 and the dielectric layer 15 are formed by performing simultaneous firing as described later, yellowing is suppressed in the front glass substrate 11. On the other hand, the rear panel 20 includes the rear glass substrate 2
1, address electrode 22, visible light reflection layer 23, partition wall 24,
The phosphor layers 25R, G, B are provided.

The rear glass substrate 21 is the front glass substrate 1
As in the case of No. 1, it is a flat plate-shaped substrate made of a sodium borosilicate glass material, and its composition contains sodium (Na).
Contains 5 wt%. Address electrodes 22 are arranged in stripes on the opposing surface of the rear glass substrate 21. The address electrode 22 is an electrode containing silver as a main component, like the display electrodes 13 and 14, and a visible light reflection layer 23 is coated so as to cover the electrode.

The visible light reflection layer 23 is, for example, a layer made of a dielectric glass containing titanium oxide in the same glass component as that constituting the dielectric layer 15 in the front panel 11, and each of the phosphor layers 25R, It has both the function of reflecting visible light generated by G and B and the function of a dielectric layer. The partition walls 24 are arranged in parallel with the address electrodes 22 on the surface of the visible light reflection layer 23. Between the partition walls 24, phosphor layers 25R, which emit red, green, and blue light,
G and B are arranged in order.

The phosphor layers 25R, G, B are layers in which phosphor particles emitting red (R), green (G), and blue (B) are bound, respectively. The PDP is attached so that the front panel 10 and the rear panel 20 face each other, and the periphery of each panel is sealed by an airtight sealing layer (not shown), and a discharge gas (for example, a discharge gas) is formed in a discharge space 26 formed therebetween. , Neon 95vol% and xenon 5vol%
Mixed gas) is enclosed at a predetermined pressure (for example, about 66.5 kPa).

<Production method of PDP> PDP according to the present invention
The manufacturing method of each electrode of the front panel and the back panel,
It is characterized by the method of firing the dielectric layer and the visible light reflecting layer. Before describing the firing method, first, the firing method in the conventional PDP manufacturing method will be described. In addition,
Since the manufacturing method of each electrode and the dielectric layer is substantially the same as the manufacturing method of the electrode and the visible light reflecting layer in the back panel, the conventional manufacturing method will be described by taking the front panel as an example.

(1) Conventional Front Panel Manufacturing Method FIGS. 3 (1) to 3 (5) are partial cross-sectional views of the front panel in each manufacturing step of the conventional front panel, and FIG. 4 shows the front panel. It is a graph which shows the relationship between baking temperature and baking time. Formation of Display Electrodes 130 and 140 First, as shown in FIG. 3A, silver particles are the main component,
A silver paste containing a glass frit, a resin, a solvent and the like is patterned on the front glass substrate 110 by a thick film screen printing method, and then the solvent is dried.

Next, as shown in FIG.
To the temperature B2 above the softening point of the glass frit (eg 5
After the temperature is raised to 80 ° C., the temperature is kept for a certain time (t1 to t
2) By keeping and firing, the resin contained in the silver paste is decomposed as shown in FIG.
By fusing silver and glass frit, display electrodes 130, 14
Form 0. Then, in order to prevent the display electrodes and the front glass substrate from being cracked, the front panel is cooled from the temperature B2 to the room temperature B1 while slowly cooling from time t2 to t3.

During this firing (time t0 to t3), silver ions contained in the electrodes 130 and 140 and the front glass substrate 110 are contained at the interface between the display electrodes 130 and 140 and the front glass substrate 110. Ion exchange with the sodium ions generated starts, and some silver ions are diffused in the front glass substrate 110. Formation of Dielectric Layer 150 Next, as shown in FIG. 3C, the display electrodes 130, 14 are formed.
On the front glass substrate 110 on which 0 is formed, a glass paste mixed with powder such as low melting point lead glass, a binder resin and a solvent is applied by a thick film screen printing method,
By drying the solvent, the glass paste to be the dielectric layer 150 is coated in a state as shown in FIG.

After that, the temperature of the front panel is raised again from the room temperature B1 to a temperature B2 (for example, 580 ° C. or higher) above the softening point of the glass frit contained in the glass paste (time t).
By heating for 4 to t5) for a predetermined time (t5 to t6) and firing, the resin in the glass paste is decomposed and the glass frit is fused as shown in FIG. 3 (5). Then, in order to prevent the front glass substrate 110 and the display electrodes 130 and 140 from being cracked, the dielectric layer 150 is formed by slowly cooling for a period of time t6 to t7. This dielectric layer 1
A protective layer is further coated on the surface of 50 to form the front panel.

By this firing (time t4 to t7), the silver contained in the electrodes 130 and 140 and the front glass substrate 11 are also included.
Ion exchange with sodium contained in 0 is performed, and silver ions are further diffused in the front glass substrate 110, while sodium ions are diffused in the dielectric layer 150. In the conventional rear panel, the display electrodes 130 and 140 in the front panel are replaced with address electrodes, and the dielectric layer 150 is replaced with a visible light reflection layer, and further, a partition and a phosphor layer are formed. Except for the above, it is manufactured in the same manner as the front panel.

As described above, in the conventional manufacturing method of the front panel (rear panel), two firings (time t) are performed for forming the display electrode and the dielectric layer (visible light reflecting layer).
0 to t3, t4 to t7), the firing time becomes longer by that amount, and silver (including silver ions) contained in the display electrode.
The amount of diffusion into the front (rear) glass substrate is increased, which causes yellowing of the panel. Specifically, in the front glass substrate formed through such two firings, 7.5 μm from the interface between the display electrode and the front glass substrate.
The concentration of silver diffused inside the front glass substrate is 0.88 wt% in a diameter of 5 μm centered at a position separated by m.
Becomes a value exceeding 0.8 wt%.

(2) Method for Manufacturing Front Panel According to the Present Invention Next, a method for manufacturing a front panel characteristic of the present invention will be described with reference to the drawings. 5 (1) to (5)
FIG. 6 is a partial cross-sectional view of the front panel in each step of manufacturing the front panel according to the present invention, and FIG. 6 is a graph showing firing temperature and firing time of the front panel according to the present invention.

Step of Applying Display Electrode Paste As shown in FIG. 5 (1), a thick film screen-printed on the front glass substrate 11 is a silver paste containing silver frit, a resin and a solvent as a main component similar to the conventional one. After being patterned and applied in a line shape by a method, it is dried. Here, the mixing ratio of the silver paste to the total paste of silver and glass frit is preferably 90 wt% or more. If it is less than 90 wt%, the viscosity of the silver paste will decrease and it will flow when formed on the front glass substrate 11 by the screen printing method, so that the desired shape may not be obtained.

Further, silver is added to the paste in an amount of 85 to 95.
It is preferable to use the one containing wt%. 85 wt%
If it is less than 100%, the shrinkage factor during firing becomes large, and it becomes difficult to obtain a dense display electrode, while if it exceeds 95% by weight, the viscosity of the silver paste becomes high. This is because thickness unevenness is large and it becomes difficult to obtain a flat electrode after firing.

The glass frit has a softening point of 350 to
It is preferably about 500 ° C. If the softening point is too low, it will soften before the resin decomposes during firing to prevent the resin from decomposing, while if the softening point is too high, the softening of the glass frit will result in insufficient adhesion between the display electrode and the front glass substrate. This is because there is a risk that it will be sufficient. The glass frit is preferably contained in the paste in a ratio of 1 to 10 wt%. Glass frit content is 1w
This is because if it is less than t%, it is difficult to obtain the adhesive force to the front glass substrate, and if it exceeds 10 wt%, the decomposition of the resin contained in the paste during firing may be hindered.

As the resin, a resin such as polymethylmethacrylate, ethylcellulose, nitrocellulose which is easily decomposed by firing, that is, the decomposition initiation temperature in air is within the range of about 300 to 350 ° C. is selected. Further, if the decomposition end temperature is lower than the softening point of the glass component contained in the dielectric layer 15, the dielectric layer 15 can be fused and solidified after the resins of the display electrodes 13 and 14 are decomposed. It is considered that bubbles generated when the resin is decomposed can be suppressed from remaining in the electrodes 13 and 14.

The above resin is used in an amount of 1 to 10 w with respect to the silver paste so as to have an optimum viscosity when the silver paste is applied.
It is preferable that t% is included. If the resin content is less than 1 wt%, the viscosity of the paste will be low, and it may be difficult to maintain the predetermined electrode shape when applied. On the contrary, if the resin content exceeds 10 wt%, If so, the viscosity of the silver paste becomes very high, and the thickness unevenness becomes large when applied on a glass substrate. The decomposition start temperature and the decomposition end temperature are TG-DTA (thermogravimetric-differential).
thermal analysis) using an analyzer, the rate of temperature rise is 10
It is the measured value when the temperature is raised at ° C / min.

As the solvent, alcohols such as ethylene glycol, terpenes such as terpineol, ketones such as methyl ethyl ketone, ethers such as carbitol and the like are used. It is preferable to use such a material that the thermal expansion coefficient of the mixture of silver and glass frit in such a silver paste is within the range of 75 to 85 × 10 ⁻⁷ / K. As a result, the display electrodes 13,
Since the coefficient of thermal expansion of 14 approximates the coefficient of thermal expansion of the front glass substrate 11, the stress due to the thermal expansion generated at the interface between the display electrodes 13 and 14 and the front glass substrate 11 during firing becomes small, and the display electrode 13, 14 is the front glass substrate 1
It is possible to suppress peeling from No. 1.

Dielectric Layer Coating Step Next, glass paste made of lead oxide type glass or bismuth oxide type glass, resin or solvent is applied on the display electrodes 13 and 14 applied in the display electrode paste applying step. It is applied by a thick film screen printing method or a die coating method.

The glass in the glass paste preferably has a coefficient of thermal expansion larger than that of the mixture of silver and glass frit used for forming the display electrodes 13 and 14. This is because the dielectric layer 15 shrinks more in the temperature lowering process described later, and thus voids are prevented from being formed at the interface between the display electrodes 13 and 14 and the dielectric layer 15. The softening point of the glass is higher than that of the glass frit used to form the display electrodes 13 and 14, and the resin in the glass paste has a decomposition start temperature of which the display electrodes 13 and 14 have a decomposition start temperature.
What is lower than the decomposition | disassembly start temperature of the resin used for the formation of is used.

The front panel thus coated with the glass paste for forming the dielectric layer 15 is left to stand in a constant temperature dryer or the like to evaporate the solvent in the paste. Firing Step First Firing Step (Time t10 to t11) Next, the front panel from which the solvent has evaporated is left to stand in a firing furnace, and as shown at time t10 to t11 in FIG.
The temperature is raised to a temperature A2 which is equal to or higher than the decomposition start temperature (about 200 ° C. for methyl methacrylate) of the resin contained in each paste of the display electrodes 13 and 14 and the dielectric layer 15 at a heating rate of 0 ° C./min. . As a result, the resin contained in the silver paste and the glass paste is decomposed.
As in (3), voids are formed in the dielectric layer 15 between the glass particles 151.

Second firing step (time t11 to t12) After reaching the temperature A2, thereafter, the temperature rising rate is slowed down to, for example, less than 5 ° C./min, or the temperature rising is stopped to maintain a constant temperature, and The temperature is maintained above the softening point of the glass frit contained in the paste and below the softening point of the glass contained in the glass paste.

As a result, the resins in the silver paste and the glass paste are completely decomposed, and the frit glass in the silver paste is fused to form the display electrodes 13 and 14 as shown in FIG. 5 (4). . Here, as described above, the decomposition start temperature of the resin in the glass paste is determined by the display electrode 1
If the temperature is lower than the decomposition start temperature of the resin of the silver paste used for forming 3, 14, the resin in the glass paste is already almost decomposed at this point and the glass particles remain, Since the supply of oxygen necessary for the decomposition of the resin in the silver paste increases through the voids formed between the particles, the resin in the silver paste easily decomposes. Further, bubbles generated when the display electrodes 13 and 14 are softened can be discharged into the firing furnace through the voids, so that bubbles are less likely to be formed in the display electrodes 13 and 14. Therefore, since the display electrodes 13 and 14 are densely configured, they have high conductivity.

In order to accelerate the decomposition of the resin in the second firing step, an oxidizing gas such as oxygen is supplied into the firing furnace so as to fill the atmosphere with an oxidizing gas atmosphere to accelerate the oxidation of the resin, or a dry gas atmosphere. By removing the water generated by the combustion of the resin to accelerate the firing, the resin in the paste can be decomposed more completely. On the other hand, since metals such as silver are easily oxidized, the inside of the firing furnace may be filled with a reducing gas atmosphere such as hydrogen to prevent the oxidation. Further, the gas generated during the decomposition of the resin may be quickly discharged to the outside of the firing furnace to reduce the pressure in the firing furnace in order to prevent bubbles from being formed in the display electrodes 13 and 14. This pressure reduction is preferably performed continuously during the second firing step, but it is possible to suppress the formation of bubbles even momentarily.

Third firing step (time t12 to t13) In the second firing step, when the resin in the silver paste and the glass paste is completely decomposed, the temperature is raised again at a constant rate (for example, 5 to 20 ° C./minute). The temperature is raised to a temperature A3 which is equal to or higher than the softening point of the glass of the dielectric layer. Fourth baking step (time t13 to t14) After that, the temperature rising rate is slower than the temperature rising rate in the third baking step, for example, lower than 5 ° C./min or the temperature rising rate is set to 0, and The temperature is maintained at A3 or higher, which is higher than the softening point of the glass. As a result, as shown in FIG. 5 (5), the glass particles 151 contained in the glass paste are fused and the dielectric layer 15 having a dense structure is formed.

Fifth firing step (time t14 to t15) Next, the temperature of the front panel, which has become hot in the firing furnace, is lowered to room temperature. Here, the dielectric layer 15 and the display electrode 1
In order to prevent cracks from entering into the cracks 3 and 14, the front panel is slowly cooled to lower the temperature.
Thereafter, the front panel is taken out from the firing furnace, and a protective layer is formed by forming a film of MgO on the surface of the dielectric layer 15 by using the CVD method or the like, whereby the front panel 10 is formed.

According to the method of manufacturing the front panel as described above, the electrodes and the dielectric layer in the front panel can be formed by only one firing, and the firing time can be shortened as compared with the conventional manufacturing method. , Diffusion of silver into the front glass substrate is suppressed, and the display electrodes 13 and 14 and the front glass substrate 1 are
The concentration of silver diffused inside the front glass substrate (diameter in the range of 5 μm) at a position distant by 7.5 μm from the interface with 1 is 0.8 wt% or less, which is smaller than in the conventional case.

(3) Method of Forming Back Panel An example of a method of manufacturing the back panel 20 will be described with reference to FIGS. The rear panel 20 is first formed on the rear glass substrate 21 by screen-printing and firing the same silver paste for electrodes as that used for forming the display electrodes to form the address electrodes 22 in a row. To do. A visible light reflection layer 2 is formed by applying a glass paste containing titanium oxide to the same components as those used to form the dielectric layer 15 thereon using a screen printing method.
3 is formed. Then, firing is performed in the same manner as in the firing process of the front panel, and the partition wall 24 is formed by repeatedly applying a paste containing a lead-based glass material at a predetermined pitch by screen printing and then firing. The discharge space 26 is divided into cells (unit light emitting regions) in the x-axis direction by the partition walls 24. Here, the address electrodes 22 and the visible light reflection layer 23 may be fired collectively after printing the partition walls 24.

Into the groove between the partition walls 24, a paste-like fluorescent ink containing red (R), green (G) and blue (B) fluorescent particles and an organic binder is applied. . By burning this at a temperature of 400 to 590 ° C. to burn off the organic binder, phosphor layers 25R, 25G, 25B formed by binding the respective phosphor particles are formed.

(4) Manufacture of PDP by pasting panels together The front panel 10 and the back panel 20 thus manufactured are stacked so that the display electrodes 13 and 14 and the address electrodes 22 are orthogonal to each other, and Glass for sealing is inserted in the peripheral edge, and the glass is baked at, for example, about 450 ° C. for 10 to 20 minutes to form an airtight seal layer (not shown) for sealing. And once the discharge space 2
After evacuating the inside of 6 to a high vacuum (for example, 1.1 × 10 ⁻⁴ Pa), a discharge gas (for example, He—Xe system, Ne—Xe) is discharged.
A PDP is produced by enclosing a system inert gas) at a predetermined pressure.

As described above, the front panel 10 and the rear panel 2 formed through such a firing step.
In the case of 0, the number of firings can be reduced as compared with the conventional case, so that the amount of silver diffused in the front glass substrate 11 can be suppressed. Therefore, since yellowing is suppressed in the PDP, it is possible to suppress deterioration in color balance. Further, since the formation of bubbles in the display electrodes 13 and 14 is suppressed, it is possible to obtain a dense display electrode having excellent conductivity. Further, since the number of firings can be reduced as compared with the conventional case, it is possible to save time in the manufacturing stage, energy required for heating, and the like, and it is also possible to reduce the manufacturing cost.

<Example> (1) Example Sample An example sample of the front panel was formed by forming the front panel of the PDP by the method described with reference to FIGS. (2) Comparative Example Sample A comparative example sample of the front panel formed by the method described with reference to FIGS.

(3) Experiment Experimental Method The amounts of silver and sodium diffused in the front glass substrate in each of the above-mentioned example samples and comparative example samples were measured. The measurement position is shown in FIG. FIG. 7 is a partial cross-sectional view of a front panel in an example sample and a comparative example sample for indicating the measurement positions of silver and sodium.
As shown in the figure, in the front glass substrates of the example sample and the comparative example sample, silver in a region P1 having a diameter of 5 μm, which is separated from the interface between the front glass substrate 11 and the display electrode 13 (14) by a distance of 7.5 μm. , The amount of sodium was measured, and comparative examination was performed.

In addition, apart from the side surface of the display electrode 13 (14) by 3 μm and from the front glass substrate 11 by 3 μm.
A region P having a diameter of 5 μm in the dielectric layer 15 at a distant position
2 and the main surface of the display electrode 13 (14) and the dielectric layer 15
Dielectric layer 15 centered on a point 5 μm away from the interface with
The amounts of silver and sodium in the region P3 having a diameter of 5 μm were measured and compared.

As a blank, the amounts of silver and sodium in the region P1 were measured on the front glass substrate before forming the front panel. Experimental condition Content of sodium contained in the front glass substrate used in the example sample and the comparative example sample = 2.96 wt.
% Equipment used: JEOL wavelength dispersion type X-ray microanalyzer JXA-8900R Accelerating voltage: 10 kV Irradiation current: 40 nA Beam diameter: 5 μm Quantitative analysis of silver and sodium by wavelength dispersion type X-ray microanalyzer using the above measuring equipment I went.

(4) Results and Discussion: Table 1 shows the experimental results.

[0059]

[Table 1] As can be seen from this table, in the example sample, the diffusion amount of silver is 0.73 wt% in the region P1, which is about 17% less than the 0.88 wt% of the comparative sample. I understand. The lower the value, the better in terms of suppressing the yellowing of the substrate, and it was difficult to set it to 0.8 wt% or less in the conventional manufacturing method, but it becomes 0.8 wt% or less in the manufacturing method of the example. I understand. Further, while silver diffuses into the front glass substrate as described above, sodium in the front glass substrate moves to the dielectric layer by ion exchange. However, in the example samples, the sodium concentration of the front glass substrate was 2%. .70 wt% and 2.96 wt% before front panel formation
It can be seen that there is not much decrease. As the sodium concentration of the front glass substrate before forming the front panel, the concentration measured on the main surface of the front glass substrate after forming the front panel on the side opposite to the electrodes can be substituted. This is because it has been experimentally confirmed that ion exchange between sodium and silver hardly occurs on the main surface opposite to the electrode.

Also in the regions P2 and P3, it can be seen that the diffusion amount of silver and sodium is smaller in the example sample than in the comparative sample. Particularly, the amount of sodium in the region P2 is 0.33 wt of the comparative sample.
%, The sample of Example is as small as 0.20 wt%, and it is considered that the ion exchange of silver and sodium is relatively suppressed in the sample of Example. This value is
It is preferably as low as possible in order to suppress yellowing of the panel, and it was difficult to reduce it to 0.25 wt% or less by the conventional method, but it is 0.25 wt% or less in the method of the example. In the region P3, in the example sample,
It can be seen that the diffusion amount of silver is 0.33 wt%, which is lower than 0.48 wt% of the comparative sample. This value is preferably as low as possible in terms of suppressing yellowing of the panel, and could not be 0.4 wt% or less by the conventional method, but could be 0.4 wt% or less by the method of the example. I understand.

Comparing the ratios of the silver concentrations in the regions P3 and P1 with each other, 0.45 was obtained for the example sample and 0.54 for the comparative example sample, which was smaller. The value of this ratio is preferably 0.5 or less in order to suppress yellowing of the panel and dielectric breakdown of the dielectric layer. That is, when the value is 0.5 or less, the diffusion of silver into the dielectric layer is suppressed, the yellowing of the panel can be suppressed, and the insulation due to the diffusion of conductive silver into the dielectric layer is achieved. It is thought that destruction can be suppressed.

These facts can reduce the number of firings in the manufacturing method of the sample of the embodiment as compared with the conventional method, so that the diffusion of silver into the front glass substrate (diffusion of sodium into the dielectric layer) is suppressed. It is believed that this is the result. <Modified Example According to the Present Embodiment> (1) In the above-described embodiments, the line-shaped display electrodes are formed on the front panel, but the present invention can be carried out even when electrodes having different shapes are formed. it can.

The PDP of this modification has substantially the same structure as the PDP of the above-mentioned embodiment, and the display electrode 2 shown in FIG.
Only the structures of 30, 240 are different. FIG. 8 is a plan view of a main part of a front panel according to this modification. As shown in the figure, the display electrodes 230 and 240 are arranged in parallel as a pair.

The display electrode 230 has line portions 231 and 23.
2 and a bridge portion 233, and a plurality of bridge portions 233 are provided between the line portions 231 and 232 that are arranged in parallel with each other with a gap.
It has a structure (hereinafter, such a structure is referred to as a "fence shape") connected by. This display electrode 23
0 is formed so as to directly contact a front glass substrate (not shown) in the display area.

The display electrode 240 has line portions 241 and 24.
2 and the bridge portion 243, and like the display electrode 230, it has a fence shape. Each display electrode 230, 240
Can be formed by a method similar to that of this embodiment, and is formed by applying a silver paste on the front glass substrate by screen printing in a fence shape.

Also in the display electrode having such a structure, by applying the manufacturing method of the above embodiment, it is possible to provide a PDP in which yellowing is suppressed. (2) In the above embodiments, the PDP has been described as an example. However, in a display panel such as a field emission display panel in which a silver electrode formed of a thick film is formed on a glass substrate, the glass substrate of the display panel is similarly used. Can be suppressed from yellowing.

[0067]

As described above, the display panel according to the present invention includes a plurality of electrodes arranged in a row on one main surface of a substrate and a dielectric layer formed so as to cover the plurality of electrodes. Is a display panel in which a first panel having a and a second panel are arranged to face each other in parallel via a partition wall, wherein the first panel has a glass composition as a substrate composition and an electrode composition as a composition. Concentration of silver having silver and diffused in a 5 μm diameter region centered on a point 5 μm away from the interface between the main surface of the electrode and the dielectric layer in the dielectric layer, and from the interface between the electrode and the substrate in the substrate Since the ratio to the concentration of silver diffused in a 5 μm diameter region centered on a point 7.5 μm apart is 0.5 or less, the diffusion of silver into the dielectric layer is small and the dielectric layer Dielectric breakdown is suppressed and silver on the substrate Distributed also seems to be less. Therefore, the yellowing of the substrate is reduced. If the panel is a front panel, yellowing of the substrate that transmits light is suppressed, and thus a decrease in color temperature of the display panel can be suppressed.

Further, the display panel manufacturing method according to the present invention includes a front panel forming step of providing a silver electrode on a front glass substrate and forming a dielectric layer so as to cover the silver electrode. In the front panel forming step, a first step of forming a pattern layer containing silver, a first resin, and a first glass on a front glass substrate, and a pattern formed in the first step. The pattern layer includes a second step of forming a coating layer containing a second resin and a second glass so as to cover the layer, and a third step of simultaneously firing the pattern layer and the coating layer. By co-firing the coating layer and the coating layer, the firing time can be shortened as compared with the conventional case, and the diffusion of silver into the front glass substrate can be suppressed. Therefore, yellowing of the front glass substrate is suppressed,
It is possible to manufacture a display panel having a higher color temperature than ever, and it is possible to shorten the manufacturing time.

[Brief description of drawings]

FIG. 1 is a partial schematic cross-sectional perspective view of a PDP according to an embodiment of the present invention.

2 is a partially enlarged cross-sectional view of the PDP in FIG. 1 when viewed from the x-axis direction.

FIG. 3 is a process diagram of a PDP for showing a method of forming a front panel of a conventional PDP, which proceeds in the order of (1) to (5).

FIG. 4 is a graph showing a relationship between a baking temperature and a baking time in a baking process of a conventional PDP front panel.

FIG. 5 is a process diagram of a PDP for showing a method of forming a front panel of the PDP according to the embodiment of the present invention,
The process proceeds in the order of numbers (1) to (5).

FIG. 6 is a graph showing the relationship between the firing temperature and the firing time in the firing process of the front panel of the PDP according to the embodiment of the present invention.

FIG. 7 is an enlarged cross-sectional view of a part of the PDP for showing the positions where the amounts of silver and sodium in the samples of Examples and Comparative Examples were measured.

FIG. 8 is a plan view showing a part of a front panel of a PDP in a modified example of the embodiment.

[Explanation of symbols]

10 Front panel 11 Front glass substrate 13, 14 Display electrodes 15 Dielectric layer 16 Protective layer 20 back panel 21 Rear glass substrate 22 Address electrode 23 Visible light reflective layer 24 partitions 25R, G, B phosphor layer 26 discharge space 151 glass grains

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masafumi Okawa 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Mitsuhiro Otani 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) Reference JP 2000-226233 (JP, A) JP 2000-156168 (JP, A) JP 10-302648 (JP, A) JP-A-9-171769 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01J 11/02 H01J 9/02 H01J 17/16

Claims (16)

(57) [Claims] 1. A electrode and those said containing disposed silver on the substrate
Rupa, channel to have a and is formed to cover the electrodes dielectric layer
A display panel wherein the panel is the interface between the electrode and the substrate during substrate
Silver concentration in a 5 μm diameter region centered on a point 7.5 μm away
The display panel is characterized by having a degree of 0.8 wt% or less . 2. A pre Kipa Nell, display panel according to claim 1, characterized in that a front panel disposed on the display direction front of the display panel. 3. The panel has glass in the composition of the substrate.
In addition to having silver in the composition of the electrode,
At a point 5 μm away from the interface between the main surface of the electrode and the dielectric layer
In the substrate, the concentration of silver diffused in the core diameter of 5 μm
At a point 7.5 μm away from the interface between the electrode and the substrate
The ratio with the concentration of silver diffused in the central 5 μm diameter region
The display panel according to claim 1 , which is 0.5 or less . 4. An electrode containing silver disposed on a substrate, and
Panel having a dielectric layer formed so as to cover the electrodes
A display panel having: 5 from the interface between the electrode main surface and the dielectric layer in the dielectric layer,
Features and to Lud I sprayed panel that silver concentration of diameter 5μm region centering point away μm is not more than 0.4 wt%. 5. A electrode and those said containing disposed silver on the substrate
Rupa, channel to have a and is formed to cover the electrodes dielectric layer
A display panel having a front Kipa panel has a silver composition of the electrode which has a sodium or glass and 2.5 wt% of the composition of the substrate,
The sodium concentration in a 5 μm diameter region centered on a point 7.5 μm away from the interface between the electrode and the substrate in the substrate is
Diameter of the main surface opposite to the main surface on which the electrode is formed is 5μ
A display panel having a sodium concentration of 90% or more in the m region. 6. Before Kipa Nell, sodium concentration of diameter 5μm region centering point away 3μm from the interface between the electrode and the substrate together away 3μm from the electrode side surface of the dielectric in the below 0.25 wt% The display panel according to claim 5, wherein the display panel is provided. Wherein said display panel is a display panel according to claim 2, characterized in that the plasma display panel. 8. A method for producing a display panel having a Rupa Ne <br/> Le forming step for forming a dielectric layer to cover the silver electrode provided with an electrode containing silver on a glass substrate, The panel forming step covers a first step of forming a pattern layer containing silver, a first resin, and a first glass on a glass substrate , and a step of covering the pattern layer formed in the first step. And a second step of forming a coating layer containing a second resin and a second glass, and a third step of co-firing the pattern layer and the coating layer. . 9. The third step comprises a first step of raising the temperature above the decomposition start temperature of the first and second resins contained in the pattern layer and the coating layer, and the softening point of the first glass. Above, the second step of maintaining the temperature range below the softening point of the second glass, and the third step of raising the temperature above the softening point of the second glass
The method of manufacturing a display panel according to claim 8 , further comprising: Wherein said second step is by than heating rate in the first step providing a time to slow its speed, the first above the softening point of the glass, and the softening point of the second glass The method for manufacturing a display panel according to claim 9 , wherein the temperature is maintained in a range below the range. 11. The method of manufacturing a display panel according to claim 8 , wherein the third step is performed under a reduced pressure atmosphere. 12. The method of claim 11, wherein the third step, the manufacturing method of a display panel according to claim 8, characterized in that under a reducing gas atmosphere. 13. The method of manufacturing a display panel according to claim 8 , wherein the third step is performed in an oxidizing gas atmosphere. 14. The method of manufacturing a display panel according to claim 8 , wherein the third step is performed in a dry gas atmosphere. 15. The display panel manufacturing method according to claim 8 , wherein in the first step, a pattern layer containing silver, a first resin and a first glass is directly formed on a glass substrate. Method. 16. The decomposition start temperature of the second resin is
The temperature is lower than the decomposition start temperature of the resin.
A method for manufacturing the display panel according to any one of 8 to 10.
Law.