JP3366895B2 - Method for manufacturing plasma display panel - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display panel used for a display of a color television receiver and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, a plasma display panel (hereinafter referred to as PDP) in a display device used in a computer, a television, etc. has been noted as a device that can realize a large size, a thin shape and a light weight. Therefore, the demand for high-definition PDP is increasing.

FIG. 16 shows a general AC (AC) PD.
It is a schematic sectional drawing which shows an example of P. In this figure, a display electrode 102 is formed on a front glass substrate 101, and the display electrode 102 is covered with a dielectric glass layer 103 and a protective layer 104 made of magnesium oxide (MgO) (for example, Japanese Patent Laid-Open No. 5-342991). (See the official gazette). Also,
Address electrodes 106 and partition walls 107 are provided on the rear glass substrate 105, and phosphor layers 110 to 112 of respective colors (red, green, and blue) are provided in the spaces between the partition walls 107.

The front glass substrate 101 is placed on the partition wall 107 of the rear glass substrate 105, and both substrates 101
A discharge gas is enclosed between 105 to form a discharge space 109. In this PDP, in the discharge space 109, vacuum ultraviolet rays (mainly having a wavelength of 147 nm) are generated due to discharge, and the phosphor layers 110 to 112 of the respective colors are excited and emitted to perform color display.

The PDP can be manufactured as follows. Apply silver paste to front glass substrate 101.
The display electrode 102 is formed by baking, the dielectric glass paste is applied and baked to form the dielectric glass layer 103, and the protective layer 104 is formed thereon. Back glass substrate 105
The address electrode 106 is formed by applying and baking silver paste on the top.
And the glass paste is applied at a predetermined pitch and baked to form the partition wall 107. And between the partition walls 107,
The phosphor layers 110 to 112 are formed by applying the phosphor paste of each color and baking at about 500 ° C. to remove the resin component and the like in the paste.

After firing the phosphor, a glass frit for sealing is applied to the outer peripheral portion of the front glass substrate 101 or the rear glass substrate 105, and calcined at about 350 ° C. to remove the resin component and the like to form a sealing glass layer. Form (frit calcination step). After that, the front glass substrate 101 and the rear glass substrate 105 described above are connected to the display electrode 102 and the address electrode 10.
Stack so that 6 and 6 are orthogonal and face each other. Then, this is heated to a temperature higher than the softening temperature of the glass for sealing (about 450 ° C.) to perform sealing (sealing step).

Thereafter, while heating the sealed panel to about 350 ° C., an internal space formed between both substrates (a space surrounded by the sealing glass layer and formed between the front glass substrate and the rear glass substrate) And the phosphor layer is facing.)
The gas is evacuated (exhaust step), and the discharge gas is introduced to a predetermined pressure (usually 4 to 7 × 10 ⁴ Pa) after the exhaust.

[0008]

The PDP manufactured in this manner is required to have improved brightness and excellent color reproducibility. Therefore, for example, the phosphor material itself used for forming the phosphor layer has been improved, but a method for solving the problem is desired from the viewpoint of the manufacturing process.

In view of the above problems, it is an object of the present invention to provide a PDP which operates with high luminous efficiency and has good color reproducibility.

[0010]

The above object is to provide a sealing material layer on the outer peripheral portion of at least one of the facing surfaces of the front substrate and the back substrate when manufacturing a PDP.
This can be achieved by setting the shape of the sealing material layer so that when the two panels are overlapped with each other, a gap that communicates the internal space and the external space is formed at one or more locations in the outer peripheral portion.

As described above, when the two panels are overlapped with each other, the sealing material is a specific means for forming a gap for communicating the internal space with the outside at one or more locations in the outer peripheral portion. When forming the layer, a convex portion or a concave portion may be formed on the sealing material layer at one or more locations on the outer peripheral portion. Alternatively, a sealing material layer is formed over the entire circumference of the opposite surface of either the front plate or the back plate, and the outer circumference of the other facing surface is partially sealed at one or more locations. You may make it form a dressing layer.

The operation and effect of the present invention will be described below. The present inventor has found that when a PDP is manufactured, the blue phosphor is thermally deteriorated as the phosphor layer is heated in the sealing step after the phosphor layer is formed, and the emission intensity and emission color of the blue phosphor are reduced. However, it has been found that the thermal deterioration of the phosphor is likely to occur when the phosphor is heated in an atmosphere containing a large amount of water, and is less likely to occur when the phosphor is heated in an atmosphere containing a small amount of water.

Here, in the case of the conventional general PDP manufacturing method, when both substrates are superposed and the sealing material is heated,
The water adsorbed on the substrate (especially the water adsorbed on the MgO protective film) evaporates in the internal space due to the heating, but since this water is confined in the internal space, the phosphor is Since it is exposed to a large amount of atmosphere, the phosphor layer is likely to be thermally deteriorated.

On the other hand, according to the PDP manufacturing method of the present invention, a gap for allowing gas to flow is secured in the outer peripheral portion until the sealing material reaches its softening temperature, so that the sealing material evaporates in the internal space. Water is released outside without being confined in the internal space. Therefore, it is possible to avoid exposing the phosphor to a high temperature and humid atmosphere. Therefore, P of the present invention
According to the DP manufacturing method, it is possible to prevent thermal deterioration of the phosphor in the sealing step (in particular, thermal deterioration of the blue phosphor).

If the step of heating the sealing material layer is performed in a dry gas atmosphere or a reduced pressure atmosphere, the effect of preventing thermal deterioration of the phosphor can be further enhanced. The "dry gas" is a gas having a vapor partial pressure smaller than usual, and it is preferable to use dried air (dry air). Water vapor partial pressure in a dry gas atmosphere is 10 Torr (1300 Pa) or less, 5T
orr (650 Pa) or less, 1 Torr (130 Pa)
It is preferable to make it smaller than the following. It can also be said that the dew point temperature of the dry gas is preferably 12 ° C. or lower, 0 ° C. or lower, and −20 ° C. or lower.

If not only the sealing step but also the fluorescent material firing step, the sealing material calcination step, the exhaust step, etc. are carried out in a dry gas atmosphere, thermal degradation of the fluorescent material in these steps can be prevented. Therefore, the emission characteristics of the blue phosphor of the PDP can be further improved. By using such a manufacturing method of the present invention, the chromaticity coordinate y (CIE color system) of the emission color when only the blue cell is turned on, or the emission when the blue phosphor layer is excited by vacuum ultraviolet rays The chromaticity coordinate y of the emitted light can be 0.08 or less. Further, the peak wavelength in the emission spectrum when only the blue cell is turned on can be set to 455 nm or less.

By improving the emission chromaticity of the blue phosphor layer, the color reproducibility of the PDP is also improved, and the color temperature in the white balance, that is, the light emission when all cells are turned on under the same power condition. The color temperature of the color can be set to 9000K or higher.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] FIG. 1 is a perspective view showing a main part of an AC surface discharge type PDP according to an embodiment, in which a display region in a central portion of the PDP is partially shown. It is shown in the figure. This PDP has a front panel plate 10 in which display electrodes 12 (scan electrodes 12a, sustain electrodes 12b), a dielectric layer 13, and a protective layer 14 are arranged on a front glass substrate 11.
And the rear panel 20 having the address electrodes 22 and the dielectric layer 23 on the rear glass substrate 21,
And the address electrode 22 are opposed to each other and are arranged in parallel with each other at an interval. The gap between the front panel plate 10 and the rear panel plate 20 is partitioned by the partition wall 24 in a stripe shape to form a discharge space 30, and the discharge space 30 is filled with a discharge gas.

In the discharge space 30, a phosphor layer 25 is arranged on the side of the rear panel 20.
The phosphor layers 25 are repeatedly arranged in the order of red, green and blue. The display electrodes 12 and the address electrodes 22 are both stripe-shaped, the display electrodes 12 are arranged in a direction orthogonal to the partition walls 24, and the address electrodes 22 are arranged in parallel with the partition walls 24. A cell structure is formed in which cells for emitting red, green, and blue colors are formed at the intersections of the display electrodes 12 and the address electrodes 22.

Although the display electrode 12 is formed in a stripe shape here, it may be implemented by, for example, an island electrode or an electrode having a hole. Further, the partition walls 24 do not have to be in the shape of stripes, and may be in the shape of, for example, a cross beam. When driving the PDP, a drive circuit (not shown) applies an address discharge pulse to the scan electrode 12a and the address electrode 22 to accumulate wall charges in the cell to be made to emit light. Light emitting display is performed by repeating the operation of performing sustain discharge in cells in which wall charges are accumulated by applying a sustain discharge pulse between the display electrode pair 12.

The address electrode 22 is a metal electrode (for example,
A silver electrode or a Cr-Cu-Cr electrode). The display electrode 12 has an electrode configuration in which a bus electrode (silver electrode, Cr—Cu—Cr electrode) having a narrow width is laminated on a wide transparent electrode made of a conductive metal oxide such as ITO, SnO ₂ or ZnO. Is preferable in order to secure a wide discharge area,
Similar to the address electrode 22, a metal electrode can be used.

The dielectric layer 13 is a layer made of a dielectric material, which is arranged so as to cover the entire surface of the front glass substrate 11 on which the display electrodes 12 are arranged. Generally, lead-based low melting point glass is used. However, it may be formed of a bismuth-based low melting point glass or a laminate of a lead-based low melting point glass and a bismuth-based low melting point glass. The protective layer 14 is made of magnesium oxide (Mg
It is a thin layer of O) and covers the entire surface of the dielectric layer 13.

The dielectric layer 23 is similar to the dielectric layer 13, but TiO ₂ particles are mixed so as to also function as a visible light reflecting layer. The partition walls 24 are made of a glass material and are provided on the surface of the dielectric layer 23 of the rear panel 20 at a constant pitch. As the phosphor material forming the phosphor layer 25, here, a blue phosphor: BaMgAl ₁₀ O ₁₇ : Eu green phosphor: Zn ₂ SiO ₄ : Mn red phosphor: (Y _x Gd _1-x ) BO ₃ : Eu will be used.

The composition of these phosphor materials has conventionally been P.
It is basically the same as that used for DP,
In the present embodiment, due to the manufacturing process, the degree of heat deterioration of the blue phosphor layer is smaller than that of the conventional one, so that the emission color is good.
Specifically, the chromaticity coordinate y value of the light emitted from the blue cell is small (the peak wavelength of blue light emission is short), and the color reproduction range near blue is wider than before.

More specifically, regarding this point, in the conventional general PDP, the chromaticity coordinate y (CIE color coordinate system) of the emission color when only the blue cell is turned on is 0.085.
Or more (peak wavelength of emission spectrum is 456 nm or more)
And the color temperature is 6000 with white balance without color correction.
It is about K. As a technique for improving the color temperature in white balance, for example, a technique in which only the width of the blue cell (partition pitch) is set large and the area of the blue cell is made larger than the area of the green cell or the red cell is also known. However, in order to increase the color temperature to 7,000 K or higher by this method, the area of the blue cell must be set to about 1.3 times or more the area of the green cell or the red cell.

On the other hand, in the PDP of this embodiment,
As will be described later, since the heat deterioration of the blue phosphor in the manufacturing process is suppressed, the chromaticity coordinate y of the emission color when only the blue-blue cell is turned on is 0.08 or less, and the peak wavelength of the emission spectrum is Since it is 455 nm or less, this makes it possible to set a large blue cell area,
It is possible to achieve a color temperature of 9000K or higher with white balance without color correction. Further, depending on the manufacturing conditions, the chromaticity coordinate y can be made lower, and the color temperature can be set to about 10,000K with white balance without color correction.

The small value of the chromaticity coordinate y of the blue cell has the same meaning as that of the short peak wavelength of blue light emission, and the smaller the value of the chromaticity coordinate y of the blue cell is. The wider color reproduction range, the relationship between the chromaticity coordinate y value of the light emitted by the blue cell, and the color temperature in white balance without color correction will be described in detail in Examples later.

In the present embodiment, the film thickness of the dielectric layer 13 is 2 according to the 40-inch class high-definition television.
The thickness of the protective layer 14 is about 0 μm and about 0.5 μm. Further, the height of the partition wall 24 is 0.1 to 0.15 mm, the partition wall pitch is 0.15 to 0.3 mm, and the film thickness of the phosphor layer 25 is 5 to 50 μm. In addition, the discharge gas to be filled is N
In the e-Xe system, the content of Xe is 5% by volume, and the filling pressure is 500 to 800 Torr (6.5 to 10.4 × 10 ^4).
Set to the range of Pa).

At the time of driving the PDP, as shown in FIG.
After connecting each driver and panel drive circuit 100 to the PDP and applying the voltage between the scan electrode 12a and the address electrode 22 of the cell to be turned on to perform the address discharge, the pulse voltage is applied between the display electrode pair 12. And sustain discharge is performed. Then, the cell emits ultraviolet rays in association with discharge,
The phosphor layer 25 converts the light into visible light. An image is displayed by lighting the cell in this manner.

[Method of Manufacturing PDP] A method of manufacturing the PDP having the above structure will be described. Preparation of Front Panel Plate Display electrode 1 is prepared by applying a silver electrode paste on screen glass substrate 11 by screen printing and baking the paste.
2 is formed, and a lead-based glass material (the composition thereof is, for example, 70% by weight of lead oxide [PbO],
Boron oxide [B ₂ O ₃ ] 15% by weight, silicon oxide [SiO ₂ ] 1
5% by weight. ) Is applied by a screen printing method and baked to form the dielectric layer 13. Further, the front panel plate 10 is manufactured by forming the protective layer 14 made of magnesium oxide (MgO) on the surface of the dielectric layer 13 by a vacuum deposition method or the like.

Production of rear panel plate: rear glass substrate 21
The address electrode 22 is formed by a method in which a silver electrode paste is screen-printed and then fired, and a paste containing TiO ₂ particles and dielectric glass particles is applied thereon by a screen-printing method and fired. As a result, the dielectric layer 23 is formed, and a paste containing glass particles is repeatedly applied by a screen printing method at a predetermined pitch, and then fired to form the partition wall 24.

Then, red, green, and blue phosphor pastes of respective colors are prepared, applied to the gaps between the partition walls 24 by a screen printing method, and baked in air to form the phosphor layers 25 of respective colors. By back panel board 2
Create 0. Each color phosphor paste used here can be manufactured as follows.

Blue phosphor (BaMgAl ₁₀ O ₁₇ : Eu)
Is, as a raw material, barium carbonate (BaCO ₃ ), magnesium carbonate (MgCO ₃ ), aluminum oxide (α-A
1 ₂ O ₃ ) is blended so that the atomic ratio of Ba, Mg, and Al is 1: 1: 10. Next, a predetermined amount of europium oxide (Eu ₂ O ₃ ) is added to this mixture. And
Mix with an appropriate amount of flux (AlF ₂ , BaCl ₂ ) in a ball mill, and under a reducing atmosphere (in H ₂ , N ₂ ) for a predetermined time (for example, 0.5 hours), temperature 1400 ° C to 1650 ° C.
It is obtained by firing at.

For the red phosphor (Y ₂ O ₃ : Eu), a predetermined amount of europium oxide (Eu ₂ O ₃ ) is added to yttrium hydroxide Y ₂ (OH) ₃ as a raw material. Then, it is obtained by mixing with an appropriate amount of flux in a ball mill and firing in air at a temperature of 1200 ° C to 1450 ° C for a predetermined time (for example, 1 hour). Green phosphor (Zn ₂ Si
O ₄ : Mn) is mixed with zinc oxide (ZnO) and silicon oxide (SiO ₂ ) as raw materials so that the atomic ratio of Zn and Si is 2: 1. Next, a predetermined amount of manganese oxide (Mn ₂ O ₃ ) is added to this mixture. Then, after mixing with a ball mill, the temperature is set to 1
It is obtained by firing at 200 ° C to 1350 ° C.

By pulverizing and sieving each color phosphor thus produced, each color phosphor particle having a predetermined particle size distribution can be obtained. A phosphor paste of each color is obtained by mixing the phosphor particles of each color with a binder and a solvent. When forming the phosphor layer 25, in addition to the screen printing method described above, a method of scanning while ejecting phosphor ink from a nozzle, or a method of using a photosensitive resin containing phosphor materials of respective colors It can also be formed by a method of producing a sheet, adhering the sheet to the surface of the rear glass substrate 21 on which the partition wall 24 is arranged, patterning by photolithography, and developing to remove an unnecessary portion.

Sealing of front panel plate and rear panel plate, evacuation and filling of discharge gas: Either one or both of the front panel plate 10 and the rear panel plate 20 thus prepared are covered with a glass frit for sealing. Apply the paste,
The sealing glass layer is formed by calcining the resin component contained in the paste to remove it, and the display electrode 12 of the front panel plate 10 and the address electrode 22 of the rear panel plate 20 are orthogonal to each other and face each other. As described above, the both panel plates 10 and 20 thus stacked are heated to soften the sealing glass layer to seal them. As a result, the inner space (both panel plates 10 and 20 surrounded by the sealing glass layer
The space between) is closed and sealed from the external space.

Although the details of this sealing step will be described later, when the front panel plate 10 and the rear panel plate 20 are overlapped with each other, a gap for communicating the internal space between the panel plates 10 and 20 with the external space is formed. The shape of the sealing glass layer is set so as to be formed on the outer peripheral portion, and since the sealing is performed in a dry air atmosphere at the time of heat sealing, it is performed from the surface of both panel plates 10 and 20 to the inside. The degree of contact of the water vapor discharged into the space with the phosphor layer is suppressed to be low, and as a result, thermal deterioration of the blue phosphor layer is suppressed.

After sealing in this way, the panel board is fired while evacuating the internal space of the sealed panel board (3).
3 hours at 50 ° C). Then, a discharge gas having the above composition is sealed at a predetermined pressure to produce a PDP.
(Detailed Description of Sealing Step) The sealing glass layer formed on the outer peripheral portion of one or both of the front panel plate 10 and the rear panel plate 20 does not have a uniform height over the entire circumference, and the front panel plate 10 and the back surface are not formed. When the panel plates 20 are overlapped with each other, a gap that connects the internal space and the external space is formed in the outer peripheral portion.

A concrete example of the sealing glass layer 15 is shown in FIG.
~ A thing as shown in Drawing 5 is considered. 3 to 5, (a) is a top view and (b) is a side view. In the example shown in FIG. 3, one panel plate (in this figure, the rear panel plate 2
The sealing glass layer 15 is provided on the outer peripheral portion of the surface 0), and the convex portions 16 are formed on the sealing glass layer 15 at substantially constant intervals.

In the example shown in FIG. 4, the sealing glass layer 1 is formed on the outer peripheral portion of the surface of one panel plate (the rear panel plate 20 in this figure).
5 are provided, and the sealing glass layer 15 has recesses 17 formed at substantially constant intervals. In the example shown in FIG. 5, as shown in (a), a sealing glass layer 15a is formed with a uniform thickness on the outer peripheral surface of one substrate (the back panel plate 20 in this figure), and (b). As shown in FIG. 5, sealing glass layers 15b scattered in island shapes are formed on the outer peripheral portion of the surface of the other substrate (the front panel plate 10 in this figure) at substantially constant intervals.

FIG. 6 is a schematic cross-sectional view of the outer peripheral portion in a state in which the front panel plate 10 and the rear panel plate 20 are superposed, (a) is the example shown in FIG. 3 and (b) is the above-mentioned diagram. This corresponds to the example shown in FIG. FIG. 6 (a),
As can be seen from (b), in any case, a gap 18 penetrating the sealing glass layer is formed in the outer peripheral portion between the front panel plate 10 and the back panel plate 20, and this gap 18 , The internal space and the external space are in communication with each other.

When the recess 17 is formed in the sealing glass layer 15 as in the example shown in FIG. 4, the recess 1
7 corresponds to this gap, and the recesses 17 allow both panel plates 1
The internal space between 0 and 20 is in communication with the external space. In this embodiment, the glass frit for sealing is
The softening point generally used conventionally is 380 to 39.
A temperature of about 0 ° C is used.

As a method for applying the paste of the glass frit for sealing on the substrate, a dispenser which is generally used for applying an adhesive is used, and the paste is discharged while scanning the dispenser. Although the method is generally used, it is also possible to apply by a screen printing method. When applying using a dispenser, it is possible to adjust the scanning speed of the dispenser and the discharge amount of the paste to adjust the thickness of the paste applied on the substrate. Therefore, the unevenness of the sealing glass layer 15 should be formed. Can be done easily.

Further, the sealing glass layer 15 having the concave portions and the convex portions can be formed by applying the paste again. For example, a sealing glass layer 1 as shown in FIG.
In order to form 5, the paste may be applied on the rear panel 20 with a uniform thickness and dried, and then the paste may be applied only on the positions where the convex portions 16 are to be formed.

Next, a process of heat-sealing both panel plates 10 and 20 which are superposed on each other with the sealing glass layer 15 interposed therebetween will be described. Here, sealing is performed by heating in dry air in a heating furnace and raising the temperature to or above the softening point temperature of the low melting point glass. FIG. 7: is a figure which shows typically the structure of the belt type heating device used for this heat sealing process.

The heating device 40 includes a heating furnace 41 for heating the panel plate, a conveyor belt 42 for conveying the panel plate so as to pass through the heating furnace 41, a gas introduction pipe 43 for introducing an atmospheric gas into the heating furnace 41, and the like. And a plurality of heaters (not shown) are installed in the heating furnace 41 along the carrying direction. Then, the heating furnace 41 is used for each heater.
By setting the temperature of each part from the inlet 44 to the outlet 45 of the substrate, the substrate can be heated with an arbitrary temperature profile, and the atmospheric gas (dry air) can be introduced from the gas introduction pipe 43. By this, the inside of the heating furnace 41 can be filled with the atmospheric gas.

The dry air as the atmospheric gas is passed through a gas dryer (not shown) that cools the air to a low temperature (minus several tens of degrees) to condense the moisture, and the amount of water vapor in the air (steam partial pressure) is changed. Can be generated by reducing. Then, the front panel plate 10 and the rear panel plate 20 described above.
A stack of and is set on the conveyor belt 42. It is preferable that the front panel plate 10 and the rear panel plate 20 aligned here are clamped by a clamp or the like so as not to be displaced.

By passing through the heating furnace 41, the set panel plates 10 and 20 are heated to the softening temperature of the sealing glass layer 15 or higher in the atmosphere of dry air. As a result, the sealing glass layer 15 is softened and both panel plates 10 and 2 are
The outer peripheral portion of 0 is sealed. (Effects of the sealing method of the present embodiment) According to the sealing method of the present embodiment, the following effects are obtained as compared with the conventional sealing method.

Usually, the front panel plate 10 and the rear panel plate 2
Gases such as water vapor are adsorbed at 0, but when these substrates are heated and heated, the adsorbed gas is released. Especially at 200 to 250 ° C., water is released from the MgO protective layer (see FIG. 14). In the conventional general manufacturing method, in the step of calcining the sealing glass, even if the gas adsorbed on the substrate escapes to some extent, then,
Since the gas is adsorbed again by bringing the temperature to room temperature in the atmosphere until the start of the sealing process, the gas adsorbed by the front panel plate and the back panel plate is released during the sealing process. Then, since the internal space surrounded by the sealing glass layer is in a hermetically sealed state, the gas released into the internal space is confined therein. It is known from the measurement results that the water vapor partial pressure in the internal space is usually 20 Torr or more.

Therefore, the phosphor layer facing the internal space is likely to be thermally deteriorated due to the influence of gas (in particular, the influence of water vapor emitted from the protective layer). When the phosphor layer (particularly the blue phosphor layer) is thermally deteriorated, the emission intensity is reduced. On the other hand, in the sealing step of the present embodiment, since the sealing glass layer 15 does not deform up to a temperature below the softening point of the sealing glass layer 15 at the time of heating, the front panel plate 10 and the rear panel A gap that connects the internal space and the external space is maintained in the outer peripheral portion of the plate 20. Therefore, the gas (water vapor) released into the internal space is released to the external space through this gap.

As a result, it is possible to suppress the deterioration of the blue phosphor during the sealing process. Furthermore, in the present embodiment, since the inside of the heating furnace 41 is in an atmosphere of dry air, the dry air flows into the internal space through the gap. Therefore, the effect of preventing the deterioration of the blue phosphor in the sealing step becomes greater.

In order to sufficiently obtain the effect of suppressing the thermal deterioration of the phosphor, the steam partial pressure of the dry air in the heating furnace 41 is set to 10 T.
It is preferable that the pressure is not higher than orrr (1300 Pa), further preferably not higher than 5 Torr (650 Pa) and not higher than 1 Torr (13
The lower the value is 0 Pa) or less, the greater the effect. In addition,
Since there is a certain relationship between the partial pressure of water vapor and the dew point temperature, in other words, using the "dew point temperature" for the water content in dry air, the lower the dew point temperature, the more the thermal deterioration during phosphor firing is suppressed. Preferably, the dew point temperature of the drying gas is 12 ° C
Hereafter, it can be said that the temperature is preferably 0 ° C. or lower and −20 ° C. or lower.

In the sealing step, the sealing glass layer 1
Since No. 5 is heated to a temperature equal to or higher than the softening point, the gap is finally eliminated, and the outer peripheral portions of the front panel plate 10 and the back panel plate 20 are sealed by the sealing glass layer 15. In addition, since the PDP produced by the manufacturing method of the present embodiment also has a small amount of water contained in the phosphor layer, it is possible to obtain an effect of causing less abnormal discharge when the PDP is driven.

Also, in the sealing step, even if no gap is formed in the outer peripheral portion, if holes are provided in the corners of the panel plates 10 and 20, there is a similar effect that moisture can escape from the internal space. It is considered that the method of the embodiment can further secure the gas flowability between the internal space and the external space. The same effect can be obtained by sealingly sealing the inner space between both panel plates 10 and 20 while forcing the dry air from the tip tube. However, according to the method of the present embodiment, the dry air can be obtained. A mechanism for feeding in is unnecessary, and the effect can be obtained more easily.

Here, a preferable form of the gap formed in the outer peripheral portion in order to obtain excellent effects will be considered. In order to obtain the effect of discharging the water generated in the internal space to the external space, the gap (the step of the convex portion 16 and the step of the concave portion 17) needs to be at least 50 μm or 100 μm, and in order to obtain a sufficient effect. In addition, the gap needs to be 300 μm or more, and preferably 500 μm or more.

Even if the ratio of the portion forming the gap in the outer peripheral portion (ratio of the length of the gap to the entire circumference) is small, the effect of draining water from the internal space can be obtained, but from the external space to the internal space. To allow gas to flow in from the outside,
It is desirable that this ratio be 50% or more. Regarding the position where the gap is formed in the outer peripheral portion, it is effective because the gas can be discharged to the outside even if the gap is formed in only one place, but it is better to provide the gap in multiple places between the internal space and the external space. Since gas distribution is improved, a larger effect can be expected.

Further, as described above, at the time of sealing, the front panel plate 10 and the rear panel plate 20 are usually sandwiched by clamps or the like, and pressure is applied to the outer peripheral portion, but this pressure is other than the gap of the sealing glass layer 15. I will concentrate on that and join. Therefore, in order to uniformly apply pressure to the entire circumference of the outer peripheral portion, the gap is dispersed in a plurality of locations throughout the outer peripheral portion rather than being concentrated at one location in the outer peripheral portion. Is preferred.

(Consideration on Water Vapor Partial Pressure in Atmosphere Gas) Regarding the fact that it is possible to prevent thermal deterioration due to heating of the blue phosphor by reducing the water vapor partial pressure in the internal space during heat sealing. , And considered based on experiments as follows. 8 and 9 show the blue phosphor (BaMgAl ₁₀ O) in air with various partial pressures of water vapor.
₁₇ : Results of measurement of relative emission intensity and chromaticity coordinate y when firing ₁₇ : Eu). As a firing condition, the peak temperature is 4
The temperature was 50 ° C., and the time of maintaining the peak temperature was 20 minutes.

The relative luminescence intensity shown in FIG. 8 is obtained by measuring the luminescence intensity measured value and the luminescence intensity measured value of the blue phosphor before firing as a reference value 1.
This is represented by a relative value when 00 is set. The emission intensity is obtained by measuring the emission spectrum from the phosphor layer using a spectrophotometer, calculating the chromaticity coordinate y value from this measurement value, and measuring the chromaticity coordinate y value and the luminance value previously measured with a luminance meter. And the value calculated from the equation (emission intensity = luminance / chromaticity coordinate y value).

The chromaticity coordinate y of the blue phosphor before firing is
Was 0.052. From the results of FIGS. 8 and 9, when the partial pressure of water vapor is 1 Torr (130 Pa) or less, no decrease in emission intensity and change in chromaticity due to heating are observed, and 10 T
At orrr (1300 Pa) or less, the decrease in emission intensity and the change in chromaticity are small, but as the water vapor partial pressure increases,
It can be seen that the relative emission intensity of blue decreases and the chromaticity coordinate y of blue increases.

By the way, the blue phosphor (BaMgAl ₁₀ O
₍₁₇ : Eu) causes the emission intensity to deteriorate and the chromaticity coordinate y value to increase because the activator Eu ²⁺ ion is oxidized by heating and becomes Eu ³⁺ ion. It has been conventionally considered that there is (J. Electr
ochem. Soc. Vol. 145, no. 11,
(November 1998) and the above-mentioned result that the y value of the chromaticity coordinate of the blue phosphor depends on the partial pressure of water vapor in the atmosphere, the Eu ²⁺ ions and oxygen in the gas atmosphere (for example, air) are considered. It is considered that the reaction relating to the deterioration is promoted by the water vapor in the gas atmosphere instead of directly reacting.

Incidentally, the blue phosphor (BaMgAl) was changed in the same manner as above by changing the heating temperature variously.
_{When the} degree of decrease in emission intensity due to the heat of ₁₀ O ₁₇ : Eu) and the change in the chromaticity coordinate y were examined, it was found that in the heating temperature range of 300 to 600 ° C., the higher the heating temperature, the lower the emission intensity due to heat. It was observed that the higher the water vapor partial pressure, the greater the decrease in emission intensity at any heating temperature. On the other hand, there was a tendency that the higher the water vapor partial pressure, the greater the change in the chromaticity coordinate y due to heat.
No tendency was found that the degree of change in the chromaticity coordinate y depends on the heating temperature.

Further, the front glass substrate 11 and the display electrode 1
2, dielectric layer 13, protective layer 14, rear glass substrate 21,
When the amount of water vapor released when each member forming the address electrode 22, the dielectric layer 23, the partition wall 24, and the phosphor layer 25 was heated, the amount of water vapor released from MgO, which is the material of the protective layer 14, was the highest. . Therefore, the main cause of the thermal deterioration of the phosphor layer 25 at the time of sealing is the protective layer 14
It is assumed that water vapor is released from (MgO).

In the present embodiment, the sealing process has been basically described, but as will be described in the following second to sixth embodiments, further improvements can be added. [Embodiment 2] In this embodiment, the sealing glass layer 15 is used.
It is devised so that the dry gas hits the sealing glass layer 15 from the side of the panel when heating and sealing the one in which both panel plates 10 and 20 are overlapped with each other via.

FIG. 10 is a view showing a state in which both panel plates 10 and 20 are sealed in a heating device in the manufacturing method of this embodiment. This heating device is the same as the above heating device 40, and a stack of both panel plates 10 and 20 is placed on the conveyor belt 42, and a gas introduction pipe 43 is provided along the conveyor belt 42. .

The conveyor belt 42 is attached to the gas introduction pipe 43.
A plurality of nozzles 43a for ejecting gas are arranged in a row along the upper surface of the nozzle. The dry air ejected from the nozzles 43a is applied from both sides of the panel plates 10 and 20 while being conveyed in the heating furnace 41 to the panel plates 10 and 20 placed on the conveyor belt 42.

In this case, the sealing glass layer 1 in the outer peripheral portion
Since the dry gas is pushed into the internal space through the gap 5 and the moisture is efficiently discharged from the internal space accordingly, the effect of suppressing the thermal deterioration of the blue phosphor is improved as compared with the first embodiment. In addition, as shown in FIG. 10, the outer peripheral portions of both panel plates 10 and 20 are clamped by a clamp 50 so as not to be displaced.

[Third Embodiment] In the present embodiment, a measure is taken so that the width of the sealing glass layer 15 after sealing is uniform. First, a method of forming partition walls along the sealing glass layer 15 will be described. In the example shown in FIG. 11, partition walls 19a and 19b are provided on the back glass substrate 21 along the inner circumference and the outer circumference of the sealing glass layer 15.

When a gap is formed in the sealing glass layer 15, the coating amount of the sealing glass differs depending on the outer peripheral portion, and therefore the width of the sealing glass layer after sealing tends to vary. That is, when the width of the sealing glass layer 15 is constant and the gap is formed in the outer peripheral portion, the portion where the gap is formed has a smaller layer thickness than the portion where the gap is not formed. The amount of the sealing glass applied is also small, and therefore the width of the sealing glass layer after sealing tends to be small. It should be noted that such a width variation degree of the sealing glass layer is determined by the gap between the sealing glass layers (sealing glass layer 15
For example, when the gap is about 500 μm, the layer width varies by about 3 mm although it depends on the height difference between the convex portion and the concave portion in FIG.

On the other hand, when the partition wall 19a and the partition wall 19b are provided as described above, when the sealing glass layer is softened, the sealing glass layer is prevented from flowing and spreading in the width direction of the layer. It is also possible to prevent variations in the width of the sealing glass layer 15 after sealing. In addition, in FIG. 11, the sealing glass layer 15 and the partition wall 19a.
Although the example in which 19b is formed is shown, the same effect can be obtained by forming any or all of the sealing glass layer 15 and the partitions 19a and 19b on the front glass substrate 11.

Next, a method for setting the width of the sealing glass layer 15 before the softening of the sealing glass layer 15 to be larger in the portion where the gap is formed than in the portion where the gap is not formed will be described. In the example shown in FIG. 12, similar to the example shown in FIG. 3, the convex portions 16 are formed on the sealing glass layer 15 at substantially constant intervals, but the convex portions 16 are formed. In the portion, the width of the layer is set smaller than that in the portion where the convex portion 16 is not formed.

By adjusting the width of the sealing glass layer 15 in this manner, the width becomes smaller at a large layer thickness, so that the coating amount of the sealing glass can be made uniform along the outer circumference. become. Therefore, the width of the sealing glass layer 15 after sealing can be made uniform. Then, by making the width of the sealing glass layer 15 uniform, it is possible to prevent the sealing glass layer from penetrating into the display region and impairing the display quality. [Embodiment 4] In this embodiment, in order to further reduce the amount of water trapped in the internal space, a sealing material having a high softening point is used to form the sealing glass layer 15.

That is, in the first embodiment, the low melting point glass having the softening point of 380 to 390 ° C. is used as the sealing material, whereas in the present embodiment, the low melting point glass having the softening point of 410 ° C. or more is selected. To use. By forming the sealing glass layer 15 using a sealing material having a high softening point in this way, a gap is maintained in the outer peripheral portion and water is discharged from the internal space to the outside until the temperature is raised to a high temperature. It will be.
Therefore, more water is discharged from the inner space to the outer space when the temperature is raised.

As described above, by using the sealing material having a softening point of 410 ° C. or higher, gas can be more efficiently discharged from the internal space to the outside, and the effect of preventing deterioration of the phosphor can be enhanced. [Embodiment 5] In the present embodiment, in order to further reduce the amount of water trapped in the internal space, the peak temperature in the sealing step is lowered so that the softening point of the sealing glass layer and the peak temperature are The temperature difference is reduced.

Conventionally, generally, the peak temperature in the sealing step was about 450 ° C. When the softening point of the glass for sealing is 380 to 390 ° C as described above, the peak temperature in the sealing step is 50 ° C or more higher than the softening point of the sealing glass. In this case, the moisture released as the temperature rises after the gap between the panel plates 10 and 20 is eliminated and the internal space is shielded is confined in the internal space, and the phosphor is thermally deteriorated by that amount. I will let you.

On the other hand, the softening point is 380 to 390 ° C.
Even if a sealing glass which is equivalent to the conventional one is used, the peak temperature in the sealing step is lower than the conventional one (for example, 410 ° C).
To 420 ° C.) and the difference between the softening point and the peak temperature is set small (20 to 30 ° C.), both panel plates 10.
Since the amount of water released into the internal space after the zero gap disappears is reduced by that much, the effect of preventing thermal deterioration of the phosphor is enhanced.

[Embodiment 6] In the present embodiment, in order to further reduce the amount of water trapped in the internal space at the time of heat sealing, sealing is performed when the temperature of both panel plates is raised in the sealing process. The glass layer 15 is kept at a temperature lower than the softening point and 250 ° C. or higher, and then heated up to the softening point temperature or higher.

Here, the temperature is kept above 250 ° C. and below the softening point of the sealing glass layer 15 for 10 minutes or more. FIG. 13 is a diagram showing an example of a temperature profile in the sealing process according to the present embodiment. In (a), a period of maintaining a constant temperature within a temperature range (indicated by a double-headed arrow W in the drawing) of 250 ° C. or higher and equal to or lower than the softening point of the sealing glass layer 15 is provided, and in (b), 250 is provided. The temperature is gradually raised within the temperature range of the softening point of the sealing glass layer 15 or higher, but in any case, the temperature is maintained at 250 ° C. or higher and the softening point of the sealing glass layer 15 or lower for 10 minutes or more. Has been done.

In the temperature range of 250 ° C. to the softening temperature of the sealing glass layer 15, the water adsorbed on the panel plates 10 and 20 (in particular, the water adsorbed on the protective layer 14) is released into the internal space, and This is a temperature range in which the moisture discharging action of discharging the water to the outside space through the gap is active. Therefore, by maintaining this temperature range, the amount of water adsorbed on the panel plates 10 and 20 at the time when the sealing glass layer 15 softens is further suppressed, and is released into the internal space after the internal space is sealed. It becomes possible to further reduce the amount of water.
Therefore, the effect of preventing thermal deterioration of the phosphor can be enhanced.

It can be confirmed by the following experiment that the adsorbed water (especially the water adsorbed on the protective layer 14) is released by heating the panel plates 10 and 20 at a temperature of 250 ° C. or higher. When the same MgO film as that used for the front panel plate 10 was heated and heated, the amount of water vapor discharged was analyzed by TDS analysis (thermal desorption gas mass spectrometry).

FIG. 14 shows the result. From this figure, it is understood that when the temperature of the MgO film used in the PDP is raised, a large amount of water vapor is discharged within the temperature range of 200 to 250 ° C. It should be noted that if the time for maintaining this temperature range is set to 30 minutes or more, a higher water discharging effect can be expected.

[Modified Examples of Embodiments] * In the above embodiments, dry air was used as the dry gas forming the atmosphere in the sealing step, but nitrogen or the like that does not react with the phosphor layer was used. The same effect can be obtained by using an active gas having a low water vapor partial pressure. However, BaMgAl
₁₀ O ₁₇ : Eu, Zn ₂ SiO ₄ : Mn and (Y, Gd) BO
₃ : When an oxide-based phosphor such as Eu is heated in an oxygen-free atmosphere, some oxygen defects may be formed and the luminous efficiency may be reduced, so the dry gas used in the sealing step contains oxygen. Is desirable.

* In the above embodiment, the sealing glass layer 15 is used.
Although a low melting point glass was used as a seal material for forming
It is also possible to use the same glass material as the partition wall 24. That is, the sealing glass layer 15 is formed on one or both of the panel plates 10 and 20 in the shape as shown in the above 3 to 5 by using the glass for partition walls.
The same effect can be obtained even when the sealing glass layer 15 is sealed by superimposing 0 and heating the sealing glass layer 15 to soften it. However, since the softening point of the partition wall glass is considerably higher than that of the low melting point glass, it is difficult to heat seal in a heating furnace in this case, but the laser light is applied from the front panel plate 10 side onto the sealing glass layer 15. The sealing glass layer 15 can be sealed by irradiating the sealing glass layer 15 with heat to soften it.

When the outer peripheral portion is irradiated with laser light for sealing, the phosphor layer is not easily exposed to high temperature, but the phosphor layer in the vicinity of the outer peripheral portion is heated. Similarly, the effect of suppressing the heat deterioration of the phosphor by discharging the moisture generated at the outside through the gap can be obtained. * In the above embodiment, the sealing step is described as being performed in a dry air atmosphere. However, in addition to the sealing step, a dry air atmosphere is used in the phosphor firing step in which the phosphor is exposed to heat and the frit calcination step. It is preferable to carry out in.

For example, when the phosphor is fired, the rear glass substrate 21 having the phosphor layer 25 formed thereon is fired in the dry air (peak temperature of 520 ° C., 10
For 1 minute), and at the time of calcining the frit, the above-mentioned heating device 40 is used to apply the glass frit for sealing to the front panel 1
0 or the back panel plate 20 is fired in dry air (peak temperature 350 ° C., 30 minutes).

As described above, even when the phosphor is fired or the frit is calcinated, the firing is performed while flowing the dry gas.
It is possible to suppress thermal deterioration due to water vapor in the atmosphere during firing of the phosphor and calcination of the frit. At this time, the value of the partial pressure of water vapor in the dry air is the same as that described in the sealing step. * In the above-mentioned embodiment, the surface discharge type PDP is described as an example, but the present invention is not limited to the surface discharge type if the PDP is manufactured through the step of sealing by heating the sealing material layer. Not limited to PDP, counter discharge PDP
It can also be applied to.

[0087]

【Example】

[0088]

[Table 1]

Panel No. shown in Table 1 1-14 PDP
Was produced. Panel No. The size of each of the PDPs 1 to 14 was 42 ″. Further, the panel structure was also common, the thickness of the phosphor layer was 30 μm, and the discharge gas was Ne.
(95%)-Xe (5%) is used, and the filling pressure is 50
It was set to 0 Torr (6.5 × 10 ⁴ Pa). Panel N
o. PDPs 1 to 13 are examples produced based on the above embodiment. The examples are common in that the sealing glass layer is formed so that a gap is formed in the outer peripheral portion between both panel plates 10 and 20 in the sealing step, but the details are different.

Panel No. 1 to 7 and panel No. 9 ~
In No. 13, as shown in FIG. 3, a sealing glass layer having a convex portion was formed on the outer periphery of the back glass substrate. Panel No. In No. 1, the convex portion is provided only at one position in the panel corner, and the panel No. In No. 2, the convex portions were provided only at four places in the four corners. Panel No. In 3 to 7 and panels 9 to 13, the convex portion is 10
It was provided over the entire circumference with a space of about cm.

The lengths of the protrusions were all about 6 mm, and the height of the protrusions and the firing atmosphere were set to various values as shown in Table 1. Panel No. In No. 8, as shown in FIG. 4, a sealing glass layer having recesses having a length of about 5 mm provided at intervals of about 10 cm is formed and sealed on the outer periphery of the back glass substrate. .

Panel No. The PDP 14 is related to the comparative example, and has a sealing glass layer provided on the outer periphery of the rear glass substrate and sealed so that there is no gap between the front plate and the rear plate before sealing. Is. The sealing material and temperature profile used for each panel are as follows. All of the sealing materials are lead oxide (65-80 wt%) as a main component.
%), Boron oxide (10 wt%), titanium oxide (5-10)
wt%) was used, but the softening point was 41
It was divided into two types, 0 ° C. and 385 ° C., and the peak temperature of the temperature profile was also set according to each softening point.

That is, the panel No. 1-8 and panel N
o. In Nos. 10 to 14, panel No. 10 was prepared using a low melting point glass having a softening point of 385 ° C. In No. 9, low melting point glass having a softening point of 415 ° C. was used. Panel No. 1 to 9 and panel No. 1
In Nos. 1 to 14, the peak temperature of the temperature profile during sealing was 450 ° C. However, the panel No. 11-1
In No. 3, while the temperature was rising during sealing,
Each standby temperature (200 ° C., 300 ° C., 400 ° C.) shown in (3) was maintained for 30 minutes. On the other hand, panel No. 10
Then, the peak temperature of the temperature profile at the time of sealing was set to 410 ° C.

The softening point of the sealing material was adjusted mainly by changing the composition ratio of lead oxide, which is the composition, and the composition ratio of other minute inclusion substances. Also, each peak temperature was kept for 20 minutes. Regarding the atmosphere during sealing, refer to Panel No. 1-3 and panel No. 5-1
In No. 3, a dry air atmosphere was used, and panel No. 3 was used. In No. 4, a vacuum atmosphere was used, and the panel No. 14 partial pressure of water vapor 15 Tor
The air atmosphere was r (1950 Pa).

(Comparative Experiment) Comparison of Light Emitting Characteristics Panel No. For PDPs 1 to 14, as emission characteristics, emission intensity when only blue cell is turned on, chromaticity coordinate y, peak wavelength of emission spectrum, and blue cell, red cell, and green cell are all turned on under the same power condition. At that time, the color temperature of white display (without color temperature correction) and the peak intensity ratio of the emission spectrum when the blue cell and the green cell were made to emit light at the same power were measured.

Regarding the emission intensity, the emission spectrum is measured using a spectrophotometer, the chromaticity coordinate y value is calculated from this measurement value, and the chromaticity coordinate y value and the luminance value previously measured by the luminance meter are calculated. Was calculated from the formula (emission intensity = luminance / y value of chromaticity coordinate). The measurement results are shown in Table 1. The emission intensity of the blue cell shown in Table 1 is the same as that of the panel No. of the comparative example. The relative emission intensity is shown with the emission intensity of 14 as 100.

FIG. 15 shows the panel No. It is an emission spectrum when only a blue cell is made to light about 7, 9, and 14. Consideration on light emission characteristics: In the measurement results of Table 1, Examples (Panel Nos. 1 to 13) and Comparative Examples (Panel N)
o. 14) and the light emission characteristics of Example, the light emission characteristics of Example are superior to those of Comparative Example (panel brightness is high and color temperature is high).

Further, in the example, a gap is formed in the outer peripheral portion, and in the example, the partial pressure of water vapor of the air flowing in the apparatus is smaller than that in the comparative example. It is considered that the water content is low, and as a result, thermal deterioration of the blue phosphor is suppressed. In addition, the panel No. Comparing the emission characteristics of 1, 2, 3
Panel No. The emission characteristics are improved in the order of 1, 2, 3. This is because the relative emission intensity is high, the chromaticity coordinate y is small, and the peak wavelength of the emission spectrum is short as the number of convex portions formed in the sealing glass layer increases, and thus the emission characteristics can be improved. Recognize.

It is considered that this is because when the number of convex portions is small, the glass substrate is bent by its own weight and the gap in the outer peripheral portion is reduced, so that it is difficult to effectively remove the water vapor generated in the internal space. Panel No. 3 and panel N
o. Comparing the light emission characteristics of panel No. 8, panel No. No. 3 is panel No. Emission characteristics are superior to those of No. 8. this is,
Panel No. It is No. 3 that the convex portion is formed on the sealing glass layer as in No. 3. As compared with the case where the concave portion is formed in the sealing glass layer as in No. 8, the length of the gap formed in the outer peripheral portion becomes larger, and as a result, the action of removing the water vapor generated in the internal space to the outside becomes larger. Thought to be from.

Panel No. Comparing the emission characteristics of Nos. 3, 5, 6, and 7, panel No. 5, No. 3, No. 6, N
o. In the order of 7, the emission characteristics are improved. It is considered that this is because the higher the height of the convex portion provided in the sealing glass layer (the larger the gap), the more effectively the water vapor generated in the internal space can be eliminated. Panel No. Panel No. 5 is a comparative example. Compared with No. 14, there is not much difference in light emission characteristics.
From this, it is understood that in order to obtain a sufficient effect, it is necessary to set the height (size of the gap) of the convex portion provided in the sealing glass layer to 100 μm or more.

Panel No. 3 and No. Comparing the light emission characteristics of panel 9, panel No. No. 9 has better light emission characteristics. This is because the higher the softening point of the sealing adhesive for sealing is, the more the gap can be maintained at a high temperature, so that the steam released to the internal space can be sufficiently exhausted, and as a result, the thermal deterioration of the blue phosphor is suppressed. It is thought to be because it is done. Panel N
o. 3 and No. Comparing the light emission characteristics of panel 10, panel N
o. No. 10 is superior in light emission characteristics. This indicates that when the sealing sealing agent having the same softening point is used, the lower the peak temperature at the time of sealing is, the more the light emission characteristics are improved.

Also, by lowering the peak temperature at the time of sealing, the amount of water vapor released into the internal space at a temperature higher than the softening point of the sealant is reduced, and as a result, thermal deterioration of the blue phosphor is suppressed. It is thought to be because it is done. Panel No. 3 and panel No. Comparing the light emission characteristics of 4,
Panel No. No. 4 is inferior in light emission characteristics.

This is the panel number. In No. 4, heating is performed in a vacuum atmosphere, but the blue phosphor, which is an oxide phosphor, is heated in an oxygen-free atmosphere, so that part of the oxygen in the base material escapes and oxygen defects are formed. It is thought to be because. Panel No. 3, No11, No. Comparing the light emission characteristics of No. 12, No. 12 3, No11, No. The light emission characteristics are improved in the order of 12. This is because in the range where the standby temperature is lower than the softening point (380 ° C.) of the sealing adhesive for sealing, the higher the standby temperature is, the more the substrate (especially MgO) is used during the standby period.
It is considered that a large amount of water vapor adsorbed on the membrane is discharged to the outside.

Panel No. No. 13 is a panel No.
3, No11, No. 12 is inferior in luminescence property. This is because, when kept at a standby temperature above the softening point (380 ° C.), a large amount of water vapor adsorbed on the substrate (especially MgO film) is discharged into the sealed internal space, and as a result, the blue phosphor It is considered that this is due to more heat deterioration.

In addition, each panel No. shown in Table 1 The chromaticity coordinate y of blue light emission and the peak wavelength of blue light emission in FIG.
5), the smaller the value of the chromaticity coordinate y of blue light emission, the shorter the peak wavelength of blue light emission. This indicates that the chromaticity coordinate y value of blue light emission is small and that the peak wavelength of blue light emission is short.

Analysis of Blue Phosphor: Panel No. 1-14
For the PDP, take out the blue phosphor from the panel,
The number of H ₂ O gas molecules desorbed from 1 g of the blue phosphor was measured by TDS analysis (thermal desorption gas mass spectrometry).
In addition, the a-axis length and c of the blue phosphor crystal were determined by X-ray diffraction.
The axial length was also measured.

In the TDS analysis, an infrared heating type thermal desorption gas mass spectrometer manufactured by Nippon Vacuum Technology Co., Ltd. was used for the following measurement. The phosphor material packed in the Ta dish was evacuated to the order of 10 -4 Pa in the preliminary exhaust chamber, then inserted into the measurement chamber and evacuated to the order of 10 ^-7 Pa. Then, using an infrared heater, the temperature rising rate from room temperature to 1100 ° C. is 10
H ₂ O desorbed from the phosphor while increasing the temperature at ℃ / min
The number of molecules (mass number 18) was measured in a scan mode with a measurement interval of 15 seconds.

The results of these measurements are as shown in Table 1. Consideration on Analysis Result of Blue Phosphor: Panel No. In the PDP blue phosphors 1 to 13,
The peak value of the number of desorbed H ₂ O molecules appearing in the region of 200 ° C. or higher in the temperature programmed desorption gas mass spectrometry is 1 × 10 ¹⁶ / g.
And the ratio of the c-axis length to the a-axis length is 4.0218.
In contrast to the following, the panel No. according to the comparative example. 1
It can be seen that the PDP blue phosphor of No. 4 exhibits values larger than the above-mentioned values.

[0109]

As described above, according to the PDP manufacturing method of the present invention, when manufacturing the PDP, the sealing material layer is formed on the outer peripheral portion of at least one of the facing surfaces of the front substrate and the rear substrate. In the step, by setting the shape of the sealing material layer such that a gap that communicates the internal space and the external space is formed at one or more locations in the outer peripheral portion when both panels are overlapped, It is possible to prevent heat deterioration of the phosphor (in particular, heat deterioration of the blue phosphor).

Here, if the step of heating the sealing material layer is performed in a dry gas atmosphere or a reduced pressure atmosphere, the effect of preventing thermal deterioration of the phosphor can be further enhanced. By using such a manufacturing method of the present invention, the chromaticity coordinate y (CIE
The chromaticity coordinate y of the light emitted when the color system) or the blue phosphor layer is excited by vacuum ultraviolet rays can be 0.08 or less. Further, the peak wavelength in the emission spectrum when only the blue cell is turned on can be set to 455 nm or less.

By improving the emission chromaticity of the blue phosphor layer, the color reproducibility of the PDP is also improved, and the color temperature in the white balance, that is, light emission when all cells are turned on under the same power condition. The color temperature of the color can be set to 9000K or higher.

[Brief description of drawings]

FIG. 1 is a perspective view of essential parts showing an AC surface discharge PDP according to an embodiment.

FIG. 2 is a diagram showing a PDP display device in which a drive circuit is connected to the PDP.

FIG. 3 is a diagram showing a specific example of the shape of the sealing glass layer in the embodiment.

FIG. 4 is a diagram showing a specific example of the shape of the sealing glass layer in the embodiment.

FIG. 5 is a diagram showing a specific example of the shape of the sealing glass layer in the embodiment.

FIG. 6 is a schematic cross-sectional view of an outer peripheral portion in a state where the front panel plate 10 and the rear panel plate 20 are superposed on each other.

FIG. 7 is a diagram showing a configuration of a belt-type heating device used in the embodiment.

FIG. 8 is a result of relative emission intensity measurement when a blue phosphor is fired in air with a changed partial pressure of water vapor.

FIG. 9 is a measurement result of chromaticity coordinates y when a blue phosphor is fired in air with a changed water vapor partial pressure.

FIG. 10 is a diagram showing a state of sealing both substrates in a heating device in the sealing method according to the second exemplary embodiment.

FIG. 11 is a diagram illustrating a sealing method according to a third embodiment.

FIG. 12 is a diagram illustrating a sealing method according to a third embodiment.

FIG. 13 is a diagram showing an example of a temperature profile in the sealing process according to the sixth embodiment.

FIG. 14 is a graph showing the results of analyzing the amount of water vapor discharged when the MgO film is heated and heated.

FIG. 15 is an emission spectrum of the PDPs of Examples and Comparative Examples when only the blue cell was turned on.

FIG. 16 is a schematic cross-sectional view showing an example of a general AC PDP.

[Explanation of symbols]

10 Front panel board 11 Front glass substrate 12 Display electrode 13 Dielectric layer 14 Protective layer 15 Sealed glass layer 16 convex 17 recess 18 Gap 19a and 19b partition wall 20 Rear panel board 21 Rear glass substrate 22 Address electrode 23 Dielectric layer 24 partitions 25 Phosphor layer 30 discharge space 40 heating device 41 heating furnace 42 Conveyor belt 43 Gas introduction pipe 43a nozzle 100 panel drive circuit

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuhisa Ishikura 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor, Utaro Miyagawa 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co. (72) Inventor Shigeo Haruki, 1006, Kadoma, Kadoma-shi, Osaka Matsushita Electric Industrial Co., Ltd. (56) Reference JP-A-61-42837 (JP, A) JP-A-5-211031 (JP, A) JP-A-11-144625 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01J 9/26 H01J 11/02

Claims (8)

(57) [Claims] 1. A phosphor layer forming step of forming a phosphor layer on at least one of the facing surfaces of the front substrate and the back substrate, and a softening point of 410 on the outer periphery of at least one of the facing surfaces of the front substrate and the back substrate. A sealing material layer forming step of forming a sealing material layer having a temperature of ℃ or more, after the phosphor layer forming step and the sealing material layer forming step, the front substrate and the back substrate, the inside of the sealing material layer A method of manufacturing a plasma display panel, comprising: a sealing step of sealing the sealing material layer by heating it at a softening temperature or higher in a state of being overlapped so as to form an internal space; The sealing material layer formed in the bonding material layer forming step communicates the internal space formed inside the sealing material layer and the outside at one or more locations in the outer peripheral portion when both panels are stacked. Method of manufacturing a plasma display panel, characterized in that between are set shape so as to form. 2. The number of facing surfaces of the front substrate and the rear substrate is small.
Phosphor layer forming step of forming a phosphor layer on one side
And an outer periphery of at least one of the facing surfaces of the front substrate and the rear substrate.
A sealing material layer forming step of forming a sealing material layer on the portion, the phosphor layer forming step and the sealing material layer forming step
After that, the front substrate and the rear substrate are placed inside the sealing material layer.
In the state of overlapping so that an internal space is formed,
Sealing by heating the sealing material layer above its softening temperature
Plasma display panel having a sealing step
In the method for manufacturing a sealing material , the sealing material layer formed in the sealing material layer forming step has one position on the outer peripheral portion when both panels are superposed.
In the above, the internal space formed inside the sealing material layer and
The shape is set so that a gap that communicates with the outside is formed.
The maximum heating temperature in the sealing step and the sealing material layer
The temperature difference from the softening point of
Plasma display panel manufacturing method. 3. The number of facing surfaces of the front substrate and the rear substrate is small.
Phosphor layer forming step of forming a phosphor layer on one side
And an outer periphery of at least one of the facing surfaces of the front substrate and the rear substrate.
A sealing material layer forming step of forming a sealing material layer on the portion, the phosphor layer forming step and the sealing material layer forming step
After that, the front substrate and the rear substrate are placed inside the sealing material layer.
In the state of overlapping so that an internal space is formed,
Sealing by heating the sealing material layer above its softening temperature
Plasma display panel having a sealing step
In the method for manufacturing a sealing material , the sealing material layer formed in the sealing material layer forming step forms an internal space formed inside the sealing material layer and an outside when both panels are stacked. Communicate
At one or more locations on the outer circumference to form a gap
At the place where the convex portion is formed, compared to other places
The plasma plasma is characterized by a narrow width.
Display panel manufacturing method. 4. The number of facing surfaces of the front substrate and the rear substrate is small.
Phosphor layer forming step of forming a phosphor layer on one side
And an outer periphery of at least one of the facing surfaces of the front substrate and the rear substrate.
A sealing material layer forming step of forming a sealing material layer on the portion, the phosphor layer forming step and the sealing material layer forming step
After that, the front substrate and the rear substrate are placed inside the sealing material layer.
In the state of overlapping so that an internal space is formed,
Sealing by heating the sealing material layer above its softening temperature
Plasma display panel having a sealing step
In the method for manufacturing a sealing material , the sealing material layer formed in the sealing material layer forming step forms an internal space formed inside the sealing material layer and an outside when both panels are stacked. Communicate
At one or more locations on the outer circumference to form a gap
The concave part is formed in, and the part where the concave part is formed is compared with other parts.
The plasma device is characterized by a wide width.
Display panel manufacturing method. 5. The number of facing surfaces of the front substrate and the rear substrate is small.
Phosphor layer forming step of forming a phosphor layer on one side
And an outer periphery of at least one of the facing surfaces of the front substrate and the rear substrate.
A sealing material layer formed step you form a sealing material layer on the part of the phosphor layer formation step and the sealing material layer forming step
After that, the front substrate and the rear substrate are placed inside the sealing material layer.
In the state of overlapping so that an internal space is formed,
Sealing by heating the sealing material layer above its softening temperature
Plasma display panel having a sealing step
In the method for manufacturing a sealing material , the sealing material layer formed in the sealing material layer forming step has one position on the outer peripheral portion when both panels are superposed.
In the above, the internal space formed inside the sealing material layer and
A gap that communicates with the outside is formed, and the gap is formed
Compared to the part where no gap is formed,
The plasma device is characterized by a wide width.
Display panel manufacturing method. 6. The number of facing surfaces of the front substrate and the rear substrate is small.
Phosphor layer forming step of forming a phosphor layer on one side
And an outer periphery of at least one of the facing surfaces of the front substrate and the rear substrate.
And a sealing material layer forming step of forming a sealing material layer on the outer surface of the front plate and the back plate.
Inside and outside the area where the sealing material layer is formed in the peripheral portion
A partition wall forming step of forming a partition wall on the side, and the phosphor layer forming step and the sealing material layer forming step.
After that, the front substrate and the rear substrate are placed inside the sealing material layer.
In the state of overlapping so that an internal space is formed,
Sealing by heating the sealing material layer above its softening temperature
And a sealing step, wherein the sealing material layer formed in the sealing material layer forming step is one position in the outer peripheral portion when both panels are superposed.
In the above, the internal space formed inside the sealing material layer and
The shape is set so that a gap that communicates with the outside is formed.
Plasma display panel characterized by being
Manufacturing method. 7. The number of facing surfaces of the front substrate and the rear substrate is small.
On the other hand, a blue firefly using BaMgAl ₁₀ O ₁₇ : Eu is used.
A phosphor layer forming step for forming a phosphor layer including a phosphor layer
And the outer periphery of at least one of the facing surfaces of the front substrate and the rear substrate.
A sealing material layer forming step of forming a sealing material layer on the portion, the phosphor layer forming step and the sealing material layer forming step
After that, the front substrate and the rear substrate are placed inside the sealing material layer.
In the state of overlapping so that an internal space is formed,
Sealing by heating the sealing material layer above its softening temperature
And a sealing step of the sealing material layer formed by the sealing material layer forming step, when superimposed both panels, one place on the outer portion
In the above, the internal space formed inside the sealing material layer and
The shape is set so that a gap that communicates with the outside is formed.
A plurality of cells, including cells in which the blue phosphor layer is arranged , are manufactured by the manufacturing method
And a c-axis length of the BaMgAl ₁₀ O ₁₇ : Eu with respect to the a-axis length of the plasma display panel.
Plas characterized by a ratio of less than 4.0218
Display panel. 8. A plasma display panel sealing device for sealing by heating a panel formed by stacking a front plate and a back plate in a state where a sealing material layer is inserted on the outer peripheral portion of the facing surface. And a sealing device for a plasma display panel, comprising a gas circulation mechanism for circulating a heating gas in a direction from the outer peripheral portion of the panel toward the internal space.