JP2010165497A - Method of manufacturing plasma display panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To materialize a highly reliable plasma display panel having no air bubble remaining in a part of a sealing material, and high fluid-tightness, and suppressing occurrence of image display defects such as disconnection or the like. <P>SOLUTION: This method of manufacturing a plasma display panel include a sealing process to dispose face-to-face a front plate in which a display electrode, a dielectric layer, and a protective layer are formed on a transparent substrate, and a back plate in which an address electrode, a barrier rib, and a phosphor layer are formed, and to seal the periphery of the front plate and the back plate. The sealing process includes a sealing material applying step to apply the sealing material to the front plate or the back plate, a drying step to dry the sealing material, a baking step to bake the sealing material, and a sealing and bonding step to dispose the front plate and the back plate face to face and seal them by softening the sealing material. A preliminary drying step to preliminarily dry the sealing material is provided after the sealing material applying step, and before the step to dry the sealing material. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method of manufacturing a plasma display panel (hereinafter referred to as PDP) which is a flat display device used for large televisions, public displays, and the like, and more specifically, a frit glass around the front and back plates of the PDP. The present invention relates to a method of manufacturing a PDP that is sealed with a.

  Since PDPs can achieve higher definition and larger screens, commercialization has progressed toward 65-inch class television receivers and large public display devices, and products exceeding 100 inches have been commercialized. ing. In particular, PDPs for television receivers are increasingly applied to high-spec high-definition televisions having more than twice the number of scanning lines as compared with the conventional NTSC system.

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

  The front plate and the back plate are opposed to each other on the electrode forming surface side, and the periphery thereof is hermetically sealed with a sealing material. The exhaust of the discharge space partitioned by the partition walls and the discharge gas (in the case of Ne-Xe) are sealed through the exhaust pipe, and after the discharge gas is sealed, the exhaust pipe is locally It is hermetically sealed by heating and melting (chip-off).

  The completed PDP is discharged by selectively applying a video signal voltage to the display electrodes, and ultraviolet rays generated by the discharge excite each color phosphor layer to emit red, green, and blue light, thereby displaying a color image. Is realized.

  Generally, a low melting point frit glass mainly composed of lead oxide or bismuth oxide is used for the dielectric layer or sealing material of the PDP. Frit glass includes amorphous frit glass that does not crystallize even when heated and remains amorphous, and crystallized frit glass that crystallizes by heating. Each material is long and short, and is often selected in consideration of matching with the manufacturing process.

In both cases of the crystallized type and the amorphous type, the sealing material is a mixture of powder glass and inorganic oxide, which are components of frit glass, and an organic solvent mainly composed of isoamyl acetate or the like. A paste-like sealing material is prepared by kneading. Next, a sealing material is applied and formed around at least one of the front plate and the back plate using a coating apparatus equipped with thick film printing, inkjet, or dispenser. Thereafter, after firing at a predetermined temperature at which the frit glass is not completely softened, the front plate and the back plate are assembled to face each other and sealed at a sealing temperature higher than the firing temperature (for example, (See Patent Document 1).
JP 2007-128860 A

  In the above-described manufacturing process of the PDP, a sealing material is arranged and formed on the peripheral portion of at least one of the front plate and the back plate, and the sealing material of the substrate on which the sealing material is arranged and formed is fired. Therefore, the sealing material is softened (melted) by raising the sealing temperature higher than the firing temperature to perform hermetic sealing.

  However, when the sealing material is applied and formed on the side of the substrate on which the sealing material is not applied and formed after sealing, for example, on the back plate, the position of the sealing material is observed from the front plate side. It was confirmed that there was an air bubble part without a part contacting the front plate.

  Such bubbles reduce the hermeticity of the PDP as a discharge vessel, and further corrode the display electrodes or address electrodes due to the effects of gas in the bubbles, resulting in disconnection and defects in displaying images. Was.

  In response to the above problems, the PDP manufacturing method of the present invention includes a front plate in which a display electrode, a dielectric layer, and a protective layer are formed on a transparent substrate, and an address electrode, a partition, and a phosphor layer. A method of manufacturing a PDP having a sealing step in which the back plate is disposed opposite to each other and the periphery of the front plate and the back plate is sealed with a sealing material. The sealing step is performed on the front plate or the back plate. A sealing material application step for applying a sealing material, a drying step for drying the sealing material, a firing step for baking the sealing material, and a front plate and a back plate are arranged oppositely to soften the sealing material. A pre-drying step for pre-drying the sealing material after the sealing material application step and before the step of drying the sealing material. And

  Here, the sealing material applied in the sealing material application step is a material containing frit glass and an organic solvent and a resin. In the preliminary drying step, the organic material of the sealing material applied in the sealing material application step is used. The sealing material may be dried in the atmosphere for a time depending on the content or viscosity expressed by the weight of the solvent.

  Moreover, when the content of the organic solvent contained in the sealing material applied in the sealing material application step is 9% by weight to 15% by weight, in the preliminary drying step, in the atmosphere at a temperature of 18 ° C. to 38 ° C., It may be dried for 1.5 minutes to 7.5 minutes depending on the content of the organic solvent.

  Moreover, when the viscosity of the sealing material applied in the sealing material application step is 0.2 Pa · s to 1.4 Pa · s, in the preliminary drying step, the viscosity is adjusted in the atmosphere at a temperature of 18 ° C. to 38 ° C. Depending on the case, it may be dried for 1.5 minutes to 7.5 minutes.

  Further, in the sealing material application step, a sealing material is applied to substantially the outer periphery of the image display area of the front plate or the back plate, and in the preliminary drying step, air at a predetermined wind speed is applied from the image display area side of the sealing material. It may be applied and dried.

  In the preliminary drying step, when the ratio of the organic solvent contained in the sealing material is 9% by weight to 15% by weight, the wind speed is 0.2 m / s to 16.0 m from the image display region side of the sealing material. / S atmosphere may be applied for 1 second to 120 seconds and dried.

  In the sealing material application step, an electrode used for image display is formed in the region where the sealing material is applied, and in the preliminary drying step, at least the sealing material in the region where the electrode is formed has a predetermined wind speed. It may be dried by applying air.

  By adopting such a manufacturing method, it is possible to realize a highly reliable PDP with no air bubbles remaining at the sealing material forming portion, high air tightness, and suppression of image display defects such as disconnection. be able to.

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

(Embodiment)
FIG. 1 is a perspective view showing the structure of a PDP in an embodiment of the present invention. The basic structure of the PDP is the same as that of a general AC surface discharge type PDP. As shown in FIG. 1, the PDP 1 has a front plate 2 made of a front glass substrate 3 and a back plate 10 made of a back glass substrate 11 facing each other, and its outer peripheral portion is sealed with a glass frit or the like. The material is hermetically sealed. A discharge gas such as neon (Ne) and xenon (Xe) is sealed at a pressure of 52 kPa to 80 kPa in the discharge space 16 inside the sealed PDP 1.

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

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

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

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

  On the other hand, the back plate 10 is formed as follows. First, a structure for the address electrode 12 is obtained by a method of screen printing a paste containing a silver material on the back glass substrate 11 or a method of forming a metal film on the entire surface and then patterning using a photolithography method. An address electrode 12 is formed by forming a material layer and firing it at a desired temperature.

  Next, a dielectric paste is applied on the rear glass substrate 11 on which the address electrodes 12 are formed by a die coating method so as to cover the address electrodes 12 to form a dielectric paste layer. Thereafter, the base dielectric layer 13 is formed by firing the dielectric paste layer. The dielectric paste is a paint containing a dielectric material such as glass powder, a binder and a solvent.

  Next, a partition wall forming paste including a partition wall material is applied on the base dielectric layer 13 and patterned into a predetermined shape to form a partition wall material layer and then fired to form the partition walls 14. Here, as a method of patterning the partition wall paste applied on the base dielectric layer 13, a photolithography method or a sand blast method can be used.

  Next, the phosphor layer 15 is formed by applying and baking a phosphor paste containing a phosphor material on the base dielectric layer 13 between the adjacent barrier ribs 14 and on the side surfaces of the barrier ribs 14. Through the above steps, the back plate 10 having predetermined components on the back glass substrate 11 is completed.

  FIG. 2 is a view showing a state in which the front plate and the back plate of the PDP in the embodiment of the present invention are sealed and joined, and the front plate 2 and the back plate 10 are sealed with a sealing material 31 around the periphery. The configuration in which the exhaust pipe 21 is provided on the back plate 10 is shown. FIG. 2A is a plan view of the PDP in the embodiment of the present invention, and FIG. 2B is a cross-sectional view taken along the line AA of the PDP shown in FIG.

  As shown in FIG. 2, the front plate 2 and the back plate 10 are arranged to face each other so that the display electrodes 6 and the address electrodes 12 are orthogonal to each other, and the periphery thereof is sealed with a sealing material 31 (this step is sealed). A landing process). Here, the periphery of the widened end portion of the exhaust pipe 21 disposed so as to cover the exhaust hole 30 provided at a predetermined position of the corner portion of the back plate 10 in the same step is a sealing material such as glass frit. The frit tablet 32 may be used for sealing. Then, after the discharge space 16 is evacuated by the exhaust pipe 21, a discharge gas containing neon (Ne), xenon (Xe) and the like is similarly supplied from the exhaust pipe 21 to a predetermined pressure (for example, in the case of Ne-Xe mixed gas, 52 kPa to PDP 1 is completed by sealing at a pressure of 80 kPa and sealing off the exhaust pipe 21.

  Next, the sealing process in which the front plate 2 and the back plate 10 are opposed to each other on the electrode forming surface side and the periphery thereof is hermetically sealed with the sealing material 31 will be described in detail. In the embodiment of the present invention, the sealing step includes a sealing material application step for applying and forming the sealing material 31 on the peripheral portion of the back plate 10, a baking step for baking the applied sealing material 31, and then A sealing joining step in which the front plate 2 and the back plate 10 are arranged to face each other and the sealing material 31 is softened and melted and sealed.

  Furthermore, a preliminary drying step and a drying step for drying the sealing material are provided between the sealing material application step and the baking step.

  As the sealing material 31, a frit glass containing no low melting point lead component, a paste-like sealing material kneaded with a predetermined filler, a resin and an organic solvent is used.

Frit glass is a non-lead borosilicate system containing at least bismuth oxide _(Bi 2 _{O 3),} the composition of bismuth oxide _(Bi 2 _{O 3)} is 70 wt% to 85 wt%, zinc oxide (ZnO) 8 wt% to 10 wt%, boron oxide (B ₂ O ₃ ) 4 wt% to 6 wt%, aluminum oxide (Al ₂ O ₃ ) 6 wt% to 8 wt%, silicon oxide (SiO ₂ ), Magnesium oxide (MgO) is 1% by weight to 3% by weight, respectively.

In particular, when the amount of bismuth oxide (Bi ₂ O ₃ ) is too small, the softening point temperature of the glass is difficult to decrease, so that poor sealing occurs. Conversely, when the amount is too large, silver (in the display electrode 6 or address electrode 12) Ag) is likely to react and foam easily. Therefore, it is preferable to set in the range of 65 wt% to 80 wt%.

  The filler of the sealing material 31 has heat resistance, and is used to adjust the thermal expansion coefficient of the sealing material 31 and to control the flow state of the frit glass. As the material, cordierite, forsterite, β-eucryptite, zircon, mullite, barium titanate, aluminum titanate, titanium oxide, molybdenum oxide, tin oxide, aluminum oxide, quartz glass, and the like are particularly preferable. Often used or mixed.

  As the organic solvent for kneading them, isoamyl acetate, terpineol or the like is used, and as the resin, acrylic resin, ethyl cellulose, nitrocellulose or the like is used. In the embodiment of the present invention, the ratio of the organic solvent to the sealing material 31 is 9% by weight to 15% by weight.

  Next, each step in the sealing process will be described. First, in the sealing material application step, the sealing material 31 is applied and formed at a predetermined position on the peripheral edge of the back plate 10 by using a coating device equipped with thick film printing, inkjet, or a dispenser. As described above, the sealing material 31 used in this sealing material application step is paste-like by being kneaded and containing a solvent and a resin.

  Thereafter, the sealing material 31 is dried in the preliminary drying step and the drying step. The preliminary drying step will be described later. In the drying step, the back plate 10 coated with the sealing material 31 is dried at about 120 ° C. by an IR furnace or the like to remove the organic solvent.

  Further, in the firing step, the back plate 10 is fired at a predetermined temperature, the resin in the sealing material 31 is removed, and the frit glass is slightly softened to fix the shape. In the embodiment of the present invention, in the firing step, the phosphor layer 15 formed on the back plate 10 is simultaneously fired.

  Next, in the sealing and joining step, the front plate 2 and the back plate 10 are disposed opposite to each other on the electrode forming surface side, and the whole is fired at a temperature higher than the firing temperature in the firing step, The front plate 2 and the back plate 10 are sealed and joined by softening the glass frit. This state corresponds to FIGS. 2 (a) and 2 (b).

  As shown in FIG. 2A, the sealing material 31 is disposed at positions along the long side of the front plate 2 and the short side of the back plate 10. Terminals for applying the voltages of the scan electrodes 2 and the sustain electrodes 3 are arranged on the short side of the front plate 2, and the terminals of the address electrodes 10 are arranged on the long side of the back plate 10. .

  Further, in the sealing and joining step of the sealing process, as shown in FIGS. 2A and 2B, the exhaust pipe disposed in the exhaust hole 30 provided at a predetermined position of the corner portion of the back plate 10. 21 is fixed by softening and melting a frit tablet 32 disposed around the head 21. The frit tablet 32 is a molded body containing the frit glass made of the same material as the sealing material 31.

  In this way, after the front plate 2 and the back plate 10 are sealed and joined and the exhaust pipe 21 is fixed, the discharge space 16 partitioned by the partition wall 14 is evacuated by the exhaust pipe 21. Thereafter, a discharge gas containing neon, xenon, or the like is sealed from the exhaust pipe 21 at a predetermined pressure (for example, a pressure of 53.2 kPa to 79.8 kPa in the case of a Ne—Xe mixed gas). Thereafter, the exhaust pipe 21 is locally heated and melted (chip-off) at an appropriate position and sealed to be hermetically sealed to complete the PDP 1.

  The PDP 1 completed by the above manufacturing method is discharged by selectively applying a video signal voltage to the display electrode 6, and ultraviolet rays generated by the discharge excite each color phosphor layer 15 to emit red, green and blue colors. Color image display is realized by emitting light.

  Here, the preliminary drying step in the sealing step of the embodiment of the present invention will be described in more detail. As described above, in the embodiment of the present invention, the organic solvent in the paste of the sealing material 31 is removed in the preliminary drying step and the drying step.

  As conditions for the preliminary drying step of the embodiment of the present invention, drying is performed for 3.0 minutes to 6.0 minutes in an atmosphere having an atmospheric temperature of 18 ° C. to 38 ° C. and a humidity of 50 ± 10 ° C. Here, when the atmospheric temperature is higher than 38 ° C., the evaporation of the organic solvent is excessively promoted as a whole, the difference in the shape change of the sealing material described later is small, and bubbles tend to remain after the PDP 1 is completed. On the other hand, it has been confirmed that when the temperature is lower than 18 ° C., the time required for the preliminary drying step is increased. More desirably, drying in the range of 24 ± 3 ° C. was most appropriate in terms of maintaining quality.

  Further, the time required for the preliminary drying step varies depending on the weight ratio or viscosity of the organic solvent in the sealing material 31 to be applied. That is, when the weight ratio of the organic solvent is large, the necessary predrying time is long, and when the ratio is small, the time is short. Also, when the viscosity is low, the required predrying time is long, whereas when the viscosity is high, it is short.

  FIG. 3 is a diagram showing the relationship between the viscosity in the sealing material to be applied and the time required for the preliminary drying step. In the figure, the abscissa indicates the viscosity, and the ordinate indicates the time of the pre-drying step required for quality to be good without leaving bubbles in the sealing material.

  FIG. 4 is a diagram showing the relationship between the content of the organic solvent in the sealing material to be applied and the time required for the preliminary drying step. In the figure, the horizontal axis represents the content, and the vertical axis represents the time required for the preliminary drying step as in FIG.

  Based on these results, in the embodiment of the present invention, the optimum time for the viscosity of the sealing material is determined and used as the preliminary drying step. As a result, even when the viscosity of the sealing material changes between production lots and the like, it is possible to shorten the production time while maintaining the quality by setting an optimal predrying time for each.

  When the content of the organic solvent contained in the sealing material applied in the sealing material application step is 9% by weight to 15% by weight, the preliminary drying step is performed in the atmosphere at a temperature of 18 ° C. to 38 ° C. It was necessary to dry for more than 5 minutes. When the sealing material has a viscosity of 0.2 Pa · s to 1.4 Pa · s, it is necessary to dry it for 1.5 minutes or more under the same conditions in the preliminary drying step.

(Second Embodiment)
From here, a second embodiment of the present invention will be described. The present embodiment is the same as the above-described embodiment except for the preliminary drying step. In the preliminary drying step of the present embodiment, the sealing material 31 is actively dried by applying air at a predetermined wind speed from a certain direction.

  FIG. 5 is a diagram showing a state of the preliminary drying step according to the second embodiment of the present invention. As shown in the figure, the sealing material 31 is applied to the substantial periphery of the back plate 10 in the sealing material application step, and a predetermined atmosphere is applied by the blower 33 in the direction of the arrow in the figure. As shown in the figure, the air is applied from the inside of the back plate 10 to the outside.

  FIGS. 5A and 5B show different embodiments. In FIG. 5A, a plurality of blowers 33 are arranged at the upper part of the back plate 10 and substantially parallel to the application direction of the sealing material 31 to send the air. In FIG. 5B, a single or a plurality of blowers 33 are arranged above the back plate 10 to send air. In any case, air is sent from the oblique upper direction of the sealing material 31, but in addition to this direction, the air is also applied from the lateral direction of the sealing material 31 along the surface of the back plate 10. Become. As described above, it is not always necessary to apply air from a plurality of directions. However, in the second embodiment of the present invention, at least air is applied from the inner side to the outer side of the back plate 10 of the sealing material 31.

  An electrode lead-out portion 34 for applying a voltage to the address electrode is formed at the long side end of the back plate 10. As described above, the effect of the second embodiment of the present invention can be obtained even if the atmosphere is applied only to the sealing material 31 formed on the upper portion of the electrode extraction portion 34 in order to prevent corrosion of the electrode.

  As a result of the examination, an atmosphere having a wind speed of 0.2 m / s to 8.0 m / s in the vicinity of the sealing material 31 is applied for 10 seconds to 120 seconds in an atmosphere of room temperature 18 ° C. to 38 ° C. and humidity 55% or less. It was confirmed that the effect was obtained. Further, by increasing the wind speed of the atmosphere, the necessary pre-drying time can be shortened and the productivity is improved. However, if the wind speed is too high, the sealing material may be peeled off. For this reason, the effect of the present invention can be achieved by applying an air having a wind speed of 2.5 ± 1.5 m / s or more for a time of 15 seconds or more, preferably at a room temperature of 18 ° C. to 38 ° C. and a humidity of 55% or less. More desirably, the quality can be stabilized efficiently in a short time by applying an atmosphere with a wind speed of 8.0 ± 2 m / s for 10 seconds or more at a room temperature of 24 ± 3 ° C. and a humidity of 50% or less.

  Further, as described above, since the atmosphere is applied to the entire back plate 10 including the sealing material 31, it is necessary to consider the electrostatic charging of the back plate 10 and the like due to the atmosphere. Therefore, in the embodiment of the present invention, the above-described blower 33 is added with the same function as the ionizer, and the neutralizing effect is also exerted. In addition, you may perform the static elimination process of the backplate 10 etc. by an ionizer after the preliminary drying step by the normal air blower 33.

    From here, the phenomenon in the embodiment of the present invention will be examined. FIG. 6 shows a cross-sectional view in the coating width direction of the sealing material 31 after the firing step in the present invention. On the other hand, FIG. 7 shows a cross-sectional view in the coating width direction of the sealing material 310 after the firing step in the prior art.

  As described above, the sealing material is applied and formed on the substantially outer periphery of the image display area of the back plate. Here, regarding the cross-sectional shape of the sealing material in the application width direction, the sealing material is examined separately for the image display region side and the non-display region side. In this case, in the second embodiment of the present invention, a predetermined atmosphere is applied from the display region side of the sealing material 31 (in the direction of the arrow in the drawing).

  As shown in FIGS. 6 and 7, the cross-sectional shape of the sealing material has a recessed portion (hereinafter, referred to as a recessed portion), and there is a point where the coating film thickness is minimized in this portion. However, comparing the two figures, in the embodiment of the present invention, the minimum point exists on the image non-display area side in the coating width direction as compared with the prior art. Further, a point where the coating film thickness is maximum exists on the display region side, and a point where the coating film thickness becomes maximum across the concave portion exists on the non-display region side. And in embodiment of this invention, it turns out that the difference of the said maximum value and the said local maximum value is large compared with a prior art.

  Since the sealing material 31 has such a shape, it comes into contact with the front plate from the point that the coating film thickness becomes maximum when the front plate is disposed oppositely and sealed on the upper portion, and the concave portion is not displayed. It is considered that the bubbles move to the region side and no bubbles remain in the recesses. As a result, high airtightness as a discharge vessel can be secured, and disconnection of the electrode due to corrosion can be prevented.

  On the other hand, the shape of the sealing material 310 in the prior art is different from the embodiment of the present invention in that the concave portion exists in the approximate center in the coating width direction, and the coating film thickness maximum value and the maximum value sandwich the concave portion. There is almost no difference. For this reason, when the front plate is opposed to the upper portion, the sealing material 310 and the front plate are in contact with each other at the maximum point and the maximum point across the concave portion, and when sealing is performed, the center in the coating width direction is applied. A recess is formed on the surface, and bubbles remain.

  The inventors consider this change in shape as follows. In the prior art, the entire sealing material 310 is forcibly heated by an IR heater or the like immediately after application. For this reason, evaporation of the organic solvent is promoted from the surface portion of the sealing material 310, and the organic solvent inside the sealing material 310 diffuses toward the surface. Along with this, the movement of the glass frit particles from the central portion to the surface portion is also accelerated. As a result, after the organic solvent is removed, the display area side and the non-display area side change evenly, and the shape of the sealing material 310 becomes a shape having a recess.

  On the other hand, in the embodiment of the present invention, air is applied to the sealing material 31 from the display region side as a preliminary drying step. For this reason, the evaporation of the organic solvent on the display area side is promoted, and the organic solvent diffuses from the non-display area side to the display area side in the sealing material 31. Along with this, diffusion of glass frit particles also occurs, and the shape of the sealing material 31 in which the display area side and the non-display area side become non-uniform as shown in FIG. 6 is obtained.

  Further, the inventors set the following new standard as a standard for non-defective products. FIG. 8 shows a cross-sectional shape after a firing step on a plane perpendicular to the application direction of a part of the sealing material. For the point p3 having the minimum coating height existing between the point p1 having the maximum coating height of the sealing material and the point p2 having the maximum coating height in the section of the sealing material coating width W, respectively. Are heights h1, h2, and h3.

  And as quality control index K, K = (h1-h2)-(h2-h3) was defined. As a result of investigations by the inventors, when the quality control index K is 0 μm or more, it is possible to maintain a good quality (a state where the diameter of the foam remaining in the sealing material is 1 mm or less), and the quality control index K is It has been found that if it is 40 μm or more, there is no bubble larger than 0.5 mm, and the quality is more desirable.

  On the other hand, when the quality control index K is smaller than 0 μm, the quality becomes defective (the diameter of bubbles remaining in the sealing material is larger than 1 mm), and the electrodes corrode due to the bubbles remaining in the sealing material forming portion. It has been found that the probability of the occurrence of image display defects such as is increased. Furthermore, it has been found that when the quality control index K is 320 μm or more, the application width of the sealing material is reduced, and the reliability of the PDP 1 is deteriorated.

  In the embodiment of the present invention, the pre-drying step is referred to. However, in addition to this, the atmosphere of the above condition is set by providing a blower in the substrate transport path from the sealing material application step to the drying step. As a result, the same effect can be obtained by the method of the preliminary drying step.

  As described above, in the method for producing the PDP of the present invention, the front plate in which the display electrode, the dielectric layer, and the protective layer are formed on the transparent substrate, and the back electrode in which the address electrode, the barrier rib, and the phosphor layer are formed. A method of manufacturing a PDP having a sealing step in which a face plate and a front plate are arranged opposite to each other and a periphery of the front plate and the back plate is sealed with a sealing material. The sealing step is performed on the front plate or the back plate. A sealing material application step, a drying step for drying the sealing material, a firing step for firing the sealing material, and a front plate and a back plate are placed opposite to each other to soften the sealing material for sealing. A pre-drying step for pre-drying the sealing material after the sealing material applying step and before the step of drying the sealing material.

  As a result, it is possible to realize a highly reliable PDP in which bubbles do not remain in a part of the sealing material, airtightness is high, and image display defects such as disconnection are suppressed.

  The effects of the second embodiment of the present invention are not limited to the arrangement and configuration of the blower 33 shown in FIG. For example, the pre-drying step does not necessarily need to be performed on the entire sealing material 31 at the same time, and scans along the application direction of the sealing material 31 by applying the air under the above-described conditions from the display region side of the sealing material 31 with a small blower Even in this form, the effect of the second embodiment of the present invention can be obtained.

  Further, in the embodiment of the present invention, the sealing material 31 is applied to the back plate 10. However, the present invention is not limited to this, and the effect of the present invention can be achieved even if applied to the front plate 2.

  As described above, the PDP manufacturing method of the present invention has a high airtightness as a discharge vessel and can realize a highly reliable PDP in which the occurrence of image display defects is suppressed.

The fragmentary perspective view of PDP in embodiment of this invention The top view and sectional drawing of PDP in embodiment of this invention The figure explaining the relationship between the viscosity of the sealing material and pre-drying time in embodiment of this invention The figure explaining the relationship between the organic-solvent ratio of the sealing material and pre-drying time in embodiment of this invention The figure explaining the state of the preliminary drying step in the 2nd Embodiment of this invention. Sectional drawing of the sealing material in the 2nd Embodiment of this invention Cross-sectional view of sealing material in the prior art Sectional drawing of the sealing material in the 2nd Embodiment of this invention

1 PDP
DESCRIPTION OF SYMBOLS 2 Front plate 3 Front glass substrate 4 Scan electrode 5 Sustain electrode 6 Display electrode 7 Light shielding layer 8 Dielectric layer 9 Protective layer 10 Back plate 11 Back glass substrate 12 Address electrode 13 Base dielectric layer 14 Partition 15 Phosphor layer 16 Discharge space 21 Exhaust pipe 30 Exhaust hole 31 Sealing material 32 Frit tablet 33 Blower 34 Address electrode lead-out part

Claims (7)

A front plate on which a display electrode, a dielectric layer, and a protective layer are formed on a transparent substrate, and a back plate on which address electrodes, barrier ribs, and a phosphor layer are formed are disposed opposite to each other, and the front plate and the back plate are disposed. A method for manufacturing a plasma display panel comprising a sealing step of sealing a periphery of a face plate with a sealing material, wherein the sealing step includes:
A sealing material application step of applying the sealing material to the front plate or the back plate;
A drying step of drying the sealing material;
A firing step of firing the sealing material;
A sealing joining step for softening and sealing the sealing material by arranging the front plate and the back plate facing each other;
A method for manufacturing a plasma display panel, comprising a pre-drying step for pre-drying the sealing material after the sealing material application step and before the step of drying the sealing material. The sealing material applied in the sealing material application step is a material containing frit glass, an organic solvent and a resin,
In the preliminary drying step, the sealing material is dried in the atmosphere for a time depending on the content or viscosity expressed by the weight of the organic solvent of the sealing material applied in the sealing material application step. The method of manufacturing a plasma display panel according to claim 1, wherein: When the content of the organic solvent contained in the sealing material applied in the sealing material application step is 9% by weight to 15% by weight, the preliminary drying step is performed in the atmosphere at a temperature of 18 ° C. to 38 ° C. The method for manufacturing a plasma display panel according to claim 2, wherein drying is performed for 1.5 minutes to 7.5 minutes or more according to the content of the organic solvent. When the viscosity of the sealing material applied in the sealing material application step is 0.2 Pa · s to 1.4 Pa · s, the viscosity in the air at a temperature of 18 ° C. to 38 ° C. in the preliminary drying step. 3. The method of manufacturing a plasma display panel according to claim 2, wherein drying is performed for 1.5 minutes to 7.5 minutes or more according to the above. In the sealing material application step, the sealing material is applied to a substantially outer periphery of an image display area of the front plate or the back plate,
2. The method of manufacturing a plasma display panel according to claim 1, wherein in the preliminary drying step, drying is performed by applying air at a predetermined wind speed from the image display region side of the sealing material. In the preliminary drying step, when the ratio of the organic solvent contained in the sealing material is 9% by weight to 15% by weight, from the image display region side of the sealing material, a wind speed of 0.2 m / s to 16. 6. The method for manufacturing a plasma display panel according to claim 5, wherein drying is performed by applying air of 0 m / s for 1 to 120 seconds. In the sealing material application step, an electrode used for image display is formed in a region where the sealing material is applied,
6. The method of manufacturing a plasma display panel according to claim 5, wherein in the preliminary drying step, at least the sealing material in the region where the electrode is formed is dried by applying air at a predetermined wind speed.

Images