JP3841172B2 - Method for manufacturing plasma display panel - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of manufacturing a plasma display panel in which a pair of substrates are sealed around a discharge space, and more particularly to a sealing method for forming a discharge space.
[0002]
The discharge space is an airtight space formed by sealing the periphery of a pair of substrates with a sealing material, and after being exhausted and purified to a stable state without impurities, a discharge gas is enclosed. Along with mass production, a method capable of quickly and reliably obtaining such a discharge space is required.
[0003]
[Prior art]
First, the structure of an AC-driven three-electrode surface discharge type PDP will be described as a typical example of a plasma display panel (hereinafter referred to as PDP). FIG. 19 is a perspective view of a state in which a part of the PDP is cut out.
[0004]
As shown in FIG. 19, on the inner surface of the front glass substrate 50, display electrodes (also referred to as sustain electrodes) X and Y for generating surface discharge along the substrate surface are provided for each line L of the matrix display. A pair is arranged. The display electrode pairs X and Y are formed by a photolithography technique, each having a wide linear transparent electrode 52 made of an ITO (Indium Tin Oxide) thin film and a narrow straight line made of a metal thin film having a multilayer structure. The bus electrode 53 is in the form of a ring.
[0005]
In addition, a dielectric layer 54 for AC (alternating current) driving is provided by screen printing so as to cover the display electrodes X and Y with respect to the discharge space. A protective film 55 made of MgO (magnesium oxide) is deposited on the surface of the dielectric layer 54.
[0006]
On the other hand, on the inner surface of the rear glass substrate 51, address electrodes 56 for generating an address discharge are arranged at a constant pitch so as to be orthogonal to the display electrodes X and Y. This address electrode 56 is also formed by a photolithography technique, and is formed by a metal film having a multi-layer structure, like the bus electrode 53.
[0007]
A dielectric layer 57 is formed by screen printing on the entire surface of the rear glass substrate 51 including the address electrode 56, and a plurality of linear partition walls 58 having a height of about 150 μm are formed on the upper layer of the dielectric layer 57. 56 are provided one by one.
[0008]
The three primary colors of R (red), G (green), and B (blue) for full color display so as to cover the surface of the dielectric layer 57 and the side surface of the partition wall 58 including the upper portion of the address electrode 56. The phosphor 60 is also provided by screen printing.
[0009]
Further, in the discharge space 59, a discharge gas such as Ne—Xe (mixed gas of Ne and Xe) that excites the phosphor by irradiating ultraviolet rays during discharge is sealed at a pressure of about several hundred torr. A sealing material (seal glass layer) 61 for sealing the discharge space 59 is provided on the periphery of the substrate.
[0010]
The front glass substrate 50 and the rear glass substrate 51 are individually formed, and finally the two substrates are bonded together with a sealing material 61 so as to have a discharge space, thereby completing the PDP.
[0011]
A conventional method for manufacturing a PDP including a step of forming a discharge space shielded from the outside by the sealing material 61 will be described with reference to FIGS. 20 and 21 are diagrams for explaining the prior art. FIG. 20 is a cross-sectional view and a plan view showing the PDP state during the sealing process, and FIG. 21 shows a processing cycle of heating and exhausting over time. FIG.
[0012]
The sealing material 61 shown in FIG. 19 is formed on the back glass substrate 51 side by applying a paste-like glass material and then solidifying it, and this sealing glass layer (sealing material) is temporarily applied in the sealing process. It is joined to the front glass substrate 50 side by melting and solidifying again.
[0013]
As shown in FIG. 20, the PDP 71 in the conventional sealing step is overlapped with a front glass substrate 72 and a rear glass substrate 73 with a sealant 74 interposed therebetween, and the periphery thereof is fixed by a number of clips 77. . The clip 77 sandwiches and fixes the front glass substrate 72 and the rear glass substrate 73 and applies a predetermined pressure to the seal portion when the sealing material 74 is melted.
[0014]
That is, in the step of sealing with the sealing material 74, in order to obtain a desired discharge space 76, the sealing material 74 interposed between the pair of glass substrates 72 and 73 is melted by heating and then defined by the partition walls. For this purpose, a predetermined pressure must be applied in the direction in which the pair of glasses 72 and 73 approach each other when the sealing material 74 is melted. A large number of clips 77 were necessary to obtain this pressure.
[0015]
Note that a conductive tube (glass tube) 75 is provided around the rear glass substrate 73 so as to communicate with the discharge space 76, and the discharge space is exhausted and filled with the discharge gas.
[0016]
In the conventional method in which the sealing process is performed in such a manner that the glass substrate pairs 72 and 73 are sandwiched and fixed using a large number of clips 77 as described above, a thin glass substrate of about 3 mm is directly sandwiched by the clips. The stress may damage the glass substrate. Therefore, it is necessary to perform sealing for a relatively long time with a weak pressure.
[0017]
The conventional processing cycle as described above is shown in FIG. 21 and will be described in more detail.
[0018]
As shown in FIG. 20, the glass substrate pairs 72 and 73 fixed by a plurality of clips 77 are carried into a heating furnace, and a seal head is attached to the conducting tube 75. The seal head is connected to an exhaust pump and a gas cylinder, and is attached to the conduction pipe 75 in a sealed state.
[0019]
In such a state, first, the heater for heating is operated to gradually increase the temperature in the heating furnace until the melting temperature of the sealing material 74 is reached (temperature rise period T1). Thereafter, the inside of the heating furnace is held at the melting temperature of the sealing material 74 for a certain time (temperature holding period T2). In this temperature holding period, the sealing material 74 is melted and the front glass substrate 72 and the rear glass substrate 73 are brought close to each other by the pressure of the clip 77 until the gap defined by the partition wall 58 (see FIG. 19) is reached.
[0020]
As described above, this step needs to be performed slowly in a state where the low-pressure clip is sandwiched, so that the temperature holding period T2 takes a relatively long time.
[0021]
Accordingly, when the gap between the front glass substrate 72 and the rear glass substrate 73 becomes a predetermined gap defined by the partition walls, the temperature in the heating furnace is lowered to the solidification temperature of the sealing material 74 (temperature drop period T3). In the period up to this point, exhaust and gas introduction in the discharge space 76 are not performed.
[0022]
Next, the temperature lowered in the temperature drop period T3 is held for a certain time (temperature hold period T4). This temperature is set to a relatively high temperature at a level at which the sealing material 74 does not melt. Simultaneously with the start of this temperature holding period T4, the discharge space 76 is exhausted through the conducting tube 75.
[0023]
This evacuation is performed to remove impurities present in the discharge space 76, and in order to promote the separation of the impure gas adsorbed on the dielectric layer, the protective film, etc., the temperature holding period in the high temperature state described above is used. Performed at T4. Therefore, the temperature holding period T4 is set on the basis of the time when the impure gas separation ends.
[0024]
Thereafter, the temperature of the heating furnace is lowered by stopping the operation of the heater for heating the heating furnace (temperature drop period T5). During this time, evacuation is performed to further remove impurities.
[0025]
When the impurities in the discharge space 76 are removed and the inside of the heating furnace is stabilized at normal temperature (normal temperature period T6), a discharge gas is introduced from the conducting tube 75 instead of exhaust. The discharge gas is, for example, a neon-xenon mixed gas, and can be introduced by switching a valve provided in the pipe.
[0026]
By passing through the process cycle demonstrated above, the front glass substrate 72 and the back glass substrate 73 are adhere | attached with a sealing material, and the predetermined discharge space 76 is formed between these substrates.
[0027]
[Problems to be solved by the invention]
In the above conventional technique, since the pressure at the time of sealing is obtained by sandwiching the periphery of the PDP 71 with a large number of clips 77, the clip 77 that directly contacts the glass substrates 72 and 73 becomes stress, and the glass substrate 72, 73 may be damaged. Therefore, sealing is performed over a relatively long time with a weak pressure.
[0028]
Therefore, a lot of time is required for the sealing step, that is, the temperature holding period T2, and the processing efficiency is deteriorated. Further, local stress is applied due to variations in the clip pressure, or a portion where sufficient pressure cannot be obtained occurs, so that the glass substrate is damaged or an incomplete sealing portion is formed.
[0029]
As a countermeasure against this problem, Japanese Patent Laid-Open No. 50-3570 discloses that a pair of substrates are placed and heated via a sealing frit, and when the frit is in a molten state, the inside of the panel container is evacuated and depressurized. A panel container sealing method is disclosed in which both substrates are sealed with a predetermined gap therebetween. However, in Japanese Patent Laid-Open No. 50-3570, since the impurities in the discharge space are removed only through the glass tube corresponding to the conducting tube 75, it takes a long time to remove the impurities, and the insufficient removal. There is a fear.
[0030]
An object of the present invention is to solve the above-mentioned problems and to provide a plasma display panel manufacturing method suitable for mass production including a process capable of performing efficient and reliable sealing and impurity removal.
[0031]
[Means for Solving the Problems]
The present invention for solving the above problems is based on the idea of performing a peripheral seal by applying a pressure difference between the inside and outside of a pair of substrates when the sealing material is melted, and thereby using a pressing force applied to the sealing material. It is what. More specifically, the method of manufacturing a plasma display panel according to the present invention includes a step of stacking a pair of substrates with a frame-shaped sealing material interposed therebetween, and a process until the sealing material between the pair of substrates is melted. The space surrounded by the sealing material is evacuated under heating conditions, and the evacuation is continued and the sealing material is heated and melted to compress the sealing material and define the gap between the substrate pair. It is characterized by sequentially performing a process and a process of forming a discharge space between the substrates by bonding and fixing the pair of substrates by solidifying the once melted sealing material.
[0032]
According to the present invention, since the sealing material is melted in a state where the pressure between the pair of substrates is reduced, the pair of substrates are attracted while crushing the sealing material due to a pressure difference between inside and outside. Therefore, the pressure applied to the substrate from the outside can be minimized, the local stress as in the past is eliminated, the time for sealing the pair of substrates with the sealing material is greatly shortened, and the exhaust is fused to the sealing material. Since the process is started before the removal, it is possible to promote the removal of impurities in the discharge space. Further, by eliminating the need for an external pressing force in this way, it is convenient to increase mass production efficiency by applying to a sealing process in a manufacturing process in which a large number of panels are cut out from a single glass substrate.
[0033]
Further, according to the present invention, in the three-electrode surface discharge panel as described above, a plurality of barrier ribs or ribs having a predetermined pattern for partitioning the discharge space are provided on the inner surface of the substrate, and the gap of the discharge space is formed by the barrier ribs. Paying attention to the points held, the frame-shaped sealing material is formed in advance higher than the height of the partition wall arranged in the discharge space, and the assembly of the substrate pair is installed in a vacuum heating furnace to surround the substrate pair. In addition, when the sealing material is melted, the substrate is directly evacuated to seal the periphery with a predetermined discharge space determined by the height of the partition wall.
[0034]
Thus, according to the present invention, the solid or gaseous impurities remaining in the discharge space can be discharged and removed at a stage before the sealing material melts through the leak gap between the sealing material and the substrate. It is possible to improve the operation characteristics and display characteristics of the panel.
[0035]
In addition, in the plasma display panel which is the subject of the present invention, a phosphor is attached to one of the substrates, particularly the substrate on the back side, together with the above-mentioned partition walls, and conventionally, the light emission characteristics tend to be deteriorated at the time of sealing. According to the present invention, heating at the time of melting the sealing material is performed in a vacuum atmosphere, and furthermore, sufficient cleaning is performed using a pressure difference between the inside and outside, so that the color temperature of the luminescent color of the phosphor can be improved. .
[0036]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0037]
FIG. 1 is a diagram showing a basic processing cycle with time in the manufacturing method of the present invention, and FIG. 2 is a diagram showing a state of a PDP in a sealing process in the manufacturing method of the present invention.
[0038]
First, the principle of the present invention will be described with reference to FIGS.
[0039]
In the present invention, the pressing force for crushing the sealing material (seal glass layer) that melts at the time of sealing generates a pressure difference between the inside of the space serving as the discharge space between the pair of glass substrates and the outside thereof. It is configured to get by. That is, the discharge space is evacuated to reduce the pressure in the space, and the sealing material is pressed by applying pressure in a direction approaching each glass substrate.
[0040]
This eliminates the need for a large number of clips used in the past to apply pressure from the outside, and enables sealing in a state where the substrate pair is temporarily fixed with a small number of clips to prevent displacement of the glass substrate pair. It becomes.
[0041]
2A and 2B show the state of the PDP in the sealing process in a cross-sectional view and a plan view.
[0042]
As shown in FIG. 2A, the PDP 1 includes a front glass substrate 2 and a rear glass substrate 3, and is sandwiched between clips 7 with a sealant 4 interposed therebetween. Electrodes, dielectric layers, partitions, and the like are formed on the inner surfaces of the front glass substrate 2 and the rear glass substrate 3, but are omitted for convenience in FIG.
[0043]
On the rear glass substrate 3, a conducting tube (glass tube) 5 for exhausting and introducing gas into the discharge space 6 is provided so as to protrude upward, and is connected to the pipe 9 through the seal head 10. It is connected. The conducting tube 5 is connected to a through hole formed in the rear glass substrate 3 in advance.
[0044]
The point to be noted here is that, as is clear from FIG. 2 (B), only a few clips 7 are arranged on the periphery of the PDP 1 so as to prevent displacement, and the clamping force is also the same as the conventional example. It is a good point if it is weak.
[0045]
In this state, the PDP 1 is placed in the heating furnace 8 and subjected to processing such as heating, exhaust, and gas introduction. Although not shown in the figure, a plurality of mounting shelves arranged in the vertical and horizontal directions are actually provided in the heating furnace 8, and a plurality of PDPs 1 are simultaneously processed according to the processing cycle shown in FIG.
[0046]
As shown in FIG. 1, first, the temperature in the heating furnace 8 is gradually increased until the melting temperature of the sealing material (seal glass layer) 4 is reached (temperature increase period T1). Thereafter, the inside of the heating furnace is held at the melting temperature of the sealing material 4 for a certain time (temperature holding period T2). Exhaust is started in this temperature holding period T2.
[0047]
The solidified sealing material (seal glass layer) 4 is melted and adhered to the substrate in the temperature holding period T2, and there is no gap with the substrate. The inside of the space 6 is depressurized, pressure is applied to the front glass substrate 2 and the back glass substrate 3 in a direction approaching each other, and the melted sealing material 4 is crushed, whereby the discharge space 6 is defined by the partition walls. It becomes a predetermined gap.
[0048]
As described above, when the gap between the glass substrate pair 2 and 3 becomes a predetermined gap, the temperature in the heating furnace 8 is lowered to the solidification temperature of the sealing material 4 (temperature drop period T3). During this time, exhaustion continues.
[0049]
Next, the temperature lowered in the temperature drop period T3 is held for a certain time (temperature hold period T4). This temperature is set to a relatively high temperature at a level at which the sealing material 4 does not melt. Exhaust continues further during the temperature holding period T4.
[0050]
The exhaust after the temperature drop period T3 is performed to remove impurities present in the discharge space 6, and impure gas (hydrocarbon, etc.) adsorbed on the dielectric layer, the protective film, the partition walls, the sealing material, and the like. In addition, since the release of moisture is promoted at a high temperature, a temperature holding period T4 for maintaining a relatively high temperature is provided.
[0051]
The temperature holding period T4 is set on the basis of the time until impure gas or the like leaving from the protective layer or the like becomes a minute amount so as not to affect the display or the like. Thereafter, the operation of the heater in the heating furnace 8 is stopped to lower the temperature in the heating furnace 8 (temperature drop period T5). During this T5 period, the exhaust is carried out to further remove impurities.
[0052]
When the impurities in the discharge space 6 are removed and the inside of the heating furnace 8 is stabilized at normal temperature (normal temperature period T6), a discharge gas is introduced from the conducting tube 5 instead of exhaust. The discharge gas is, for example, a neon-xenon mixed gas, and can be introduced by opening a valve provided in the pipe 9. At this time, the operation of the exhaust pump is stopped and the valve on the exhaust side is closed.
[0053]
After that, the PDP 1 is completed by removing the conducting tube 5 and closing the through hole of the back glass substrate 3 formed in the conducting tube 5 without releasing the airtight state in the discharge space 6.
[0054]
According to the processing cycle according to the present invention described above, the sealing material 4 can be crushed by adjusting the pressure in the discharge space without applying pressure to the glass substrate pairs 2 and 3 from the outside. Accordingly, since there is no stress that directly contacts the glass substrates 2 and 3, it is possible to seal in a short time by exhausting to some extent so that the inside of the discharge space 6 becomes a predetermined pressure. In addition, impurities in the discharge space can be removed and cleaned by exhaust.
[0055]
3 to 5 are diagrams for explaining the first embodiment of the present invention. FIG. 3 is a cross-sectional view showing the inside of the PDP until sealing is performed, and FIG. FIG. 5 is a perspective view of the processed rear glass substrate, and FIG.
[0056]
As shown in FIG. 3A, the front glass substrate 12 is provided with a display electrode 15, a dielectric layer 16, and a protective film 17. On the other hand, on the rear glass substrate 13, the address electrodes 18 and the dielectric layer 19, the partition wall 20 defining the discharge region and the discharge gap, and the phosphor 21 disposed between the partition walls 20, and the sealing material 14 and the sealing material 14 are provided. A barrier 22 is formed to prevent intrusion into the inside.
[0057]
Formation of panel constituent members such as electrodes, dielectric layers, barrier ribs and phosphors is performed by a general process such as photolithography or screen printing.
[0058]
The perspective view of FIG. 4 shows the configuration of the sealing material 14 and the barrier 22 more clearly. That is, the sealing material (seal glass layer) 14 is formed in a frame shape around the rear glass substrate 13, and the barrier 22 is formed slightly inside the sealing material 14 at a predetermined interval. Yes. The barrier 22 prevents the sealing material 14 from entering the display area when exhausting, and has an interval to secure an exhaust path with respect to the vicinity of the sealing material 14.
[0059]
In FIG. 4, for convenience of explanation, the address electrode, the dielectric layer, the partition wall, and the like are omitted, and only the sealing material 14 and the barrier 22 are shown.
The front glass substrate 12 and the back glass substrate 13 having such a structure are overlapped to obtain the state shown in FIG. The overlapped substrate pair is fixed by a misalignment prevention clip having a weak spring force that does not apply stress to the substrate. In this state, as is clear from FIG. 3B, the sealing material 14 formed on the rear glass substrate 13 supports the front glass substrate 12, and the partition walls 20, the front glass substrate 12 (protective film 17), There is a gap between them. Further, since all of the upper end portion of the sealing material 14 is not flat, a small gap is formed between the sealing material 14 and the front glass substrate 12.
[0060]
The front glass substrate 12 and the rear glass substrate 13 temporarily fixed in this manner are carried into a heating furnace, and heating and exhaust processing are started. (See Fig. 2 for the state in the heating furnace)
FIG. 5 is a diagram for explaining this processing cycle, wherein (A) shows the temperature profile in the heating furnace, and (B) shows the pressure profile in the discharge space. As shown in FIG. 5A, in the heating furnace, first, the heater is operated to gradually increase the furnace temperature from the normal temperature (temperature increase period T1). The sealing material 14 used in the present embodiment is mainly composed of low-melting glass, and its melting temperature is approximately 400 ° C., and therefore the temperature in the heating furnace is increased to 400 ° C. during the temperature increase period T1. Let
[0061]
When the furnace temperature reaches around 400 ° C., the sealing material 14 is melted, and the upper end surface of the molten sealing material adheres to the front glass substrate 12, so that there is a gap between the sealing material and the front glass substrate 12. Disappear. As a result, the gap (discharge space) between the front glass substrate 12 and the rear glass substrate 13 is sealed.
[0062]
Thereafter, the temperature (400 ° C.) at which the sealing material 14 is melted is held for a certain time (temperature holding period T2). In this temperature holding period T2, evacuation is started as shown in FIG. 5B, and the pressure inside the sealed discharge space is reduced to a predetermined reduced pressure, for example, about 50,000 to 70,000 Pa (Pascal). This pressure is a pressure necessary for crushing the sealing material 14 to be melted to draw the front glass substrate 12 and the rear glass substrate 13, and is appropriately selected according to the material of the sealing material 14, the volume in the discharge space, and the like. To do.
[0063]
When the discharge space reaches a desired pressure (50,000 to 70,000 Pa), the exhaust is temporarily stopped to maintain the pressure. At this time, since the sealing material 14 is melted and the inside of the discharge space is in a reduced pressure state, the front glass substrate 12 and the back glass substrate 13 are drawn while crushing the sealing material 14. On the other hand, since the exhaust is stopped in the middle, the molten sealing material does not flow into the discharge space.
[0064]
After a predetermined time has elapsed, the front glass substrate 12 and the back glass substrate 13 are drawn to a position where they are supported by the partition walls 20 as shown in FIG. In the present embodiment, the temperature holding period T2 is set to 10 minutes, and a desired discharge space can be obtained by this set time.
[0065]
Thereafter, the temperature in the heating furnace is lowered to the solidification temperature of the sealing material 14 (temperature drop period T3), and the sealing with the sealing material 14 is completed.
[0066]
Next, the temperature lowered in the temperature drop period T3 is held for a certain time (temperature hold period T4). This temperature is set to 350 ° C., which is a relatively high temperature at a level at which the sealing material 14 does not melt.
[0067]
In the first half of the temperature holding period T4, the exhaust is resumed and the pressure in the discharge space is set to 10 as in the conventional example. ^-3 After a high vacuum of about Pa, a neon-xenon mixed gas, which is a discharge gas, is introduced into the discharge space from the conducting tube, and then evacuation is started again. The gas introduction performed here is for washing out impurities inside the discharge space, and after discharging the discharge gas to every corner of the space, it is exhausted to enable more reliable impurity removal. .
[0068]
After this, the temperature holding period T4 continues for a predetermined time. By keeping this at a high temperature, the generation of impurity gas from the dielectric layers 16 and 19 and the protective film 17 is promoted. It is for removing.
[0069]
Further, at the time of evacuation immediately after the introduction of the gas during the temperature holding period T4, the aging process is performed by applying a predetermined voltage to the address electrodes. This aging process is intended to stabilize the address electrodes.
[0070]
The temperature holding period T4 is set to a time when gas is no longer generated from the panel constituent members, and then the operation of the heater in the heating furnace is stopped to lower the temperature in the heating furnace (temperature drop period T5). . During this period as well, evacuation is carried out to further remove impurities.
[0071]
When the impurities in the discharge space are removed and the inside of the heating furnace is stabilized at normal temperature (normal temperature period T6), a discharge gas, that is, a neon-xenon mixed gas is introduced from the conducting tube instead of exhaust.
[0072]
By passing through such a processing cycle, the glass substrate pairs 12 and 13 are bonded together to form a desired discharge space defined by the partition wall, and a discharge gas is sealed in the discharge space.
[0073]
According to the present embodiment, the sealing process that has conventionally required several hours, that is, the temperature holding period T2, can be set to several tens of minutes. In addition, since the number of steps for attaching a large number of clips is not required, the production efficiency is greatly improved.
[0074]
Further, when the thickness of the seal portion of the PDP manufactured in this embodiment was measured at a plurality of locations, it was almost the same as the preset reference value, and it was confirmed that the desired sealing was performed.
[0075]
Furthermore, it has been confirmed that the luminance and the color temperature of the phosphor are improved as compared with the case of sealing with the conventional clip pressure, and the color temperature is improved by a little less than 20%, and the current value is also stable. This is probably because the discharge space was formed with high accuracy, the impure gas was exhausted sufficiently, and the high-temperature treatment in the atmosphere during sealing was avoided.
[0076]
FIG. 6 is a plan view for explaining a modified example of the barrier according to the first embodiment of the present invention. The barrier in this modification more reliably prevents the seal material from entering the display area.
[0077]
That is, as shown in FIG. 6, a barrier 22 ′ having an exhaust path in a direction inclined with respect to the direction in which the sealing material 14 extends is formed inside the sealing material 14 of the rear glass substrate 13 ′. . When the barrier 22 ′ has such a shape, it is possible to reliably prevent the sealing material 14 from entering while securing the exhaust path.
[0078]
The barrier in this embodiment prevents the sealing material that melts when the discharge space is exhausted from entering the display area. However, if the exhaust force or the exhaust time is selected, the sealing material is drawn inward. The barrier is not necessarily required because it can be held in place.
[0079]
7A and 7B are diagrams showing a PDP according to the second embodiment of the present invention. FIG. 7A is a plan view and FIG. 7B is a cross-sectional view. In the present embodiment, a plurality of panels that are particularly suitable for the present invention are formed simultaneously.
[0080]
Along with mass production, a method of obtaining a plurality of PDP panel substrates from a single (a pair of opposing) glass substrates has started to be employed for efficient production. In this method, components such as electrodes, dielectric layers and partition walls are simultaneously formed on a large glass substrate for a number corresponding to a plurality of panels, and then the large glass substrate is cut and divided for each panel. Thus, this is a manufacturing technique for finally obtaining a plurality of PDPs, and the manufacturing efficiency can be improved.
[0081]
The PDP 31 shown in FIG. 7 (here, the state in which the two sheets are integrated together is also referred to as PDP), and as described above, the patterns of the electrodes, dielectric layers, etc. are changed so that two PDPs can be simultaneously Is formed.
[0082]
Two sets of frame-shaped sealing materials 34a and 34b are interposed between the large front glass substrate 32 and the rear glass substrate 33 having the size of two sheets, and the rear glass substrate. 33 is provided with two sets of conducting pipes 35a and 35b in a region surrounded by the sealing materials 34a and 34b.
[0083]
When two sets of sealing materials 34a and 34b are formed in this way, the sealing material is disposed also in the central portion of the glass substrate, unlike the case where one sealing material is formed only in the peripheral portion of the substrate. Become. Therefore, in the conventional technique for obtaining the pressing force against the sealing material by the clip, it is not possible to apply pressure to the sealing material at the central portion. Therefore, a jig (such as a large clip) for applying a pressing force to the sealing material located at the center of the glass substrate from above and below is required, and the apparatus becomes large.
[0084]
On the other hand, since this invention is the structure which obtains the pressing force with respect to a sealing material by decompressing the inside of discharge space, such a clip (a large-sized clip is included) is not required. Therefore, even when the sealing material is present at the center of the glass substrate as in this embodiment, it is possible to perform sealing easily and reliably.
[0085]
The PDP 31 shown in FIG. 7 is carried into the heating furnace in this state, and sealed and exhausted.
[0086]
In the heating furnace, the PDP 31 is provided with different seal heads on the conducting pipes 35a and 35b, respectively, and discharge of the discharge space and introduction of the discharge gas are performed through separate piping.
[0087]
The subsequent processing cycle is the same as that of the first embodiment shown in FIG. After this processing cycle, as in the first embodiment, after introducing the discharge gas and removing the conducting tubes 35a and 35b, the PDP 31 is unloaded from the heating furnace, and the front glass substrate 32 and the back glass substrate 33 are mounted. By cutting along the central cutting line 36, two PDPs are completed simultaneously.
[0088]
According to the present embodiment described above, when two PDPs are formed at the same time in order to improve mass productivity, the central portion of the glass can be reliably sealed without applying pressure from the outside. Become.
[0089]
8A and 8B are views showing a PDP according to the third embodiment of the present invention. FIG. 8A is a plan view and FIG. 8B is a cross-sectional view. In the present embodiment, four PDPs are formed at the same time in order to further increase mass productivity as compared with the second embodiment.
[0090]
The PDP 41 shown in FIG. 8 (here, the state in which the four sheets are integrated is also referred to as a PDP) is formed by simultaneously forming four PDP sheets by changing the pattern of electrodes, dielectric layers, and the like as described above. Yes.
[0091]
In this embodiment, the large glass substrate is partitioned into four regions along the cutting line, and frame-shaped sealing materials 44a, 44b, 44c, and 44d are disposed in the partitioned regions, and the rear glass substrate 43 Four sets of conducting pipes 45a, 45b, 45c, and 45d are disposed in a region surrounded by each sealing material.
[0092]
Here, the four sets of conducting tubes 45a, 45b, 45c, and 45d are provided close to each other in the central part of the substrate where the four regions on the rear glass substrate 43 are adjacent to each other, so that the common piping is used. At the same time, it is devised so that exhaust and discharge gas can be introduced.
[0093]
That is, in the PDP 41 of the present embodiment, four sets of conducting pipes 45a, 45b, 45c, and 45d are connected to one pipe 47 via the seal head in the heating furnace as shown in FIG. 8B. become. Therefore, as shown by the arrows, when exhaust and discharge gas are introduced through the pipe 47, processing is simultaneously performed in the discharge spaces formed individually.
[0094]
Since the processing of the PDP 41 carried into the heating furnace is the same processing cycle as that of the first embodiment shown in FIG. 5, the description thereof is omitted, but the sealing materials 44a, 44b, 44c, and 44d are melted. Since each discharge space is depressurized in a state, sealing can be easily performed without applying pressure from the outside.
[0095]
Also in the present embodiment, as in the second embodiment, the sealing material is also disposed in the region (central portion) other than the peripheral portion of the glass substrate, but by reducing the discharge space as described above, Since the sealing is performed by obtaining the pressure for pressing the sealing material, the sealing of this portion can be performed reliably.
[0096]
After sealing in this way, impurities in the discharge space are removed, discharge gas is introduced, and the conducting tubes 45a, 45b, 45c, and 45d are further removed. Thereafter, the PDP 41 is unloaded from the heating furnace, and the front glass substrate 42 and the rear glass substrate 43 are cut along the cutting line 46 to complete four PDPs simultaneously.
[0097]
According to the present embodiment described above, when four PDPs are formed at the same time in order to increase mass productivity, the central portion of the glass can be reliably sealed without applying external pressure. Become.
[0098]
Further, since the conducting tubes 45a, 45b, 45c, and 45d are provided close to the center portion of the rear glass substrate 43 and exhaust and discharge gas are introduced through the common pipe 47, the structure of the exhaust system is simple. And its control becomes easy.
[0099]
In the above embodiment, gas is introduced into the discharge space during the temperature holding period T4 in order to wash out impurities in the discharge space. This gas introduction time is set to extend the temperature holding period of T2 shown in FIG. A similar effect can be obtained by introducing discharge gas, nitrogen gas, argon, or the like from the conducting tube into the discharge space after about 10 minutes have elapsed from the start of T2, and then starting exhaust again.
[0100]
Moreover, in the said embodiment, although exhaust_gas | exhaustion was started after the temperature in a heating furnace reached the temperature which fuse | melts a sealing material, you may perform this exhaustion start in the state below a sealing material melting temperature.
[0101]
The fourth embodiment is an example in which the start of exhaust is synchronized with the start of the heat treatment in the heating furnace, and FIGS. 9A and 9B show the temperature profile in the furnace and the discharge space in the treatment cycle. The pressure profile is shown.
[0102]
In this embodiment, as shown in FIG. 9A, exhaust is started at the start of temperature rise, and exhaust is temporarily stopped in the middle of the temperature holding period T2. Thus, when exhaust from the conducting tube is started at the same time as the temperature rises, as shown in FIG. 9B, the pressure in the discharge space does not change at first, and it starts from around 400 ° C. which is the melting temperature of the sealing material. The pressure in the discharge space begins to drop.
[0103]
In other words, until the temperature in the furnace reaches the melting temperature of the sealing material, the gas (air) in the furnace enters the discharge space through the gap existing between the unmelted sealing material and the front glass substrate. Due to the drawing, the pressure in the discharge space does not change. At this time, impurities (such as hydrocarbons) in the discharge space are discharged to the outside of the discharge space through the conducting tube by the airflow drawn into the discharge space from the periphery of the substrate. Therefore, impurity removal can be further improved.
[0104]
After that, when the melting temperature of the sealing material is reached, the sealing material starts to come into close contact with the front glass substrate, and the discharge space is sealed. Therefore, when the exhaust is continued, the pressure in the discharge space decreases and the exhaust is stopped. The pressure becomes constant.
[0105]
Thus, in this embodiment, since exhaust is started before the sealing material is fused, removal of impurities in the discharge space can be promoted. In this case, it is more effective if the atmosphere in the furnace is a clean gas such as nitrogen.
[0106]
Note that the processing after holding the pressure is substantially the same as that of the first embodiment, and thus the description thereof is omitted.
[0107]
10 to 12 are views for explaining a fifth embodiment of the present invention. FIG. 10 is a cross-sectional view showing a state in which the glass substrate pairs 101 and 102 are overlapped, and FIG. , 102 shows a sealing process, and FIG. 12 shows a processing cycle. Various electrodes, dielectric layers, protective films, barrier ribs, phosphors, and the like are arranged on the front glass substrate 101 and the rear glass substrate 102 as in the first embodiment.
[0108]
The fifth embodiment differs greatly from the first to fourth embodiments described above in that a minute gap is formed between the sealing material and the substrate before sealing the sealing material, and the substrate pair is connected in this state. The object is to exhaust the impure gas in the pair of substrates through the gap between the substrate pair by evacuating while heating at a temperature at which the sealing material does not melt.
[0109]
The front glass substrate 101 and the back glass substrate 102 are overlapped and fixed with a plurality of clips 7 made of a heat-resistant and elastic material such as nickel / chrome / molybdenum steel. At this time, the clip 7 is attached so that the fastening position of the clip 7 is close to the partition wall 20 closest to the sealing material 104 of the discharge space 103 formed by the front glass substrate 101 and the rear glass substrate 102. With the clip 7 attached, the tightening force of the clip 7 is adjusted so that the top of the partition wall 20 is in close contact with the MgO protective film (not shown) of the front glass substrate 101. For the adjustment of the tightening force, the most preferable clip 7 may be selected from clips 7 having various tightening forces prepared in advance.
[0110]
Here, the overlapping process of the front glass substrate 101 and the rear glass substrate 102 is completed. At this time, the height of the sealing material is larger than the height of the partition wall, and the clamping force of the clip 7 causes the periphery of the substrate pair. Warping as shown in FIG. 10 occurs. An important point in this process is that the top of the sealing material 104 on the front glass substrate 101 and the back glass substrate 102 overlapped due to the warpage of the pair of substrates and the unevenness of the sealing top due to the variation in the formation of the sealing material 104 itself. In this manner, a gap 105 in which the gas can freely move is formed.
[0111]
A formed glass frit 119 formed in advance is placed in the through hole 115 of the pair of substrates 101 and 102 (hereinafter referred to as PDP 100) thus superposed (see FIG. 11). The formed frit glass 119 is fixed to the rear glass substrate 102 with a resin that decomposes by low-temperature heating to such an extent that the molded frit glass 119 does not move (is not displaced) when the PDP 100 is transported to the next process.
[0112]
Next, the PDP 100 is put into a vacuum heating furnace 110 that can be evacuated while being heated. The vacuum heating furnace 110 is heated by a heater (not shown), and the inside of the furnace is evacuated by a vacuum pump (not shown) connected via an exhaust port 111 to bring the furnace into a high vacuum state. Is possible. Further, as will be described later, an elevating seal head 112 for exhausting only the discharge space 103 or filling the discharge space 103 with a discharge gas is installed in the vacuum heating furnace 110 via a bellows 113. .
[0113]
In this vacuum heating furnace 110, the PDP 100 is subjected to the processing cycle shown in FIG. The vacuum heating furnace 110 starts heating and evacuates the furnace. The sealing material 104 used in this example has a characteristic that the softening point temperature is about 420 ° C. to 440 ° C., and the melting start temperature is about 370 ° C. to 390 ° C. In the vicinity of 350 ° C. to 370 ° C. just before the melting start temperature, the gap 105 between the top of the sealing material 104 and the substrate is still maintained. Therefore, in this temperature range of the vacuum exhaust, it is possible to exhaust the impure gas remaining in the space of the PDP 100 from the periphery of the PDP 100 through the gap 105. This is the temperature region that can be removed. Therefore, the substrate temperature is temporarily maintained until the impure gas can be removed (period T2 in FIG. 12).
[0114]
Next, the temperature is raised to about 400 ° C. to 410 ° C. (period T3 in FIG. 12), and the sealing material 104 is softened. At this time, the sealing material 104 starts to deform due to the stress of the front glass substrate 101 and the rear glass substrate 102 due to the tightening force of the clip 7, but the viscosity is such that it does not deform without this stress. When the deformation progresses and the height of the sealing material 104 is deformed to the same height as the partition wall 20, the deformation stops.
[0115]
Further, in the sealing material 104, there are microbubbles that exist when the sealing material 104 is molded and pre-baked. When the periphery of the PDP 100 is evacuated to a low pressure state, the microbubbles may become giant bubbles as the viscosity of the sealing material 104 decreases. If the giant bubbles are present, the purpose of the sealing material 104 for maintaining the discharge space 103 of the plasma display panel in an airtight state cannot be maintained, and the reliability of the panel may be lowered. For this purpose, the pressure around the PDP 100 is temporarily raised in the process of raising the temperature of the substrate from 370 ° C. to 410 ° C. (period T3 in FIG. 12). By this operation, even if microbubbles are present, reliability can be ensured without causing the bubbles to become extremely large.
[0116]
This temporary increase in pressure can be achieved by introducing an inert gas such as Ar or a discharge gas into the vacuum heating furnace 110. The furnace pressure at this time has an optimum value depending on the balance with the viscosity of the sealing material 104. If the temperature of the sealing material is lower than the softening point of the sealing material and the viscosity is in the middle viscosity range, no bubbles are observed even if the pressure is reduced to about several tens of KPa, and if the viscosity is near the softening start temperature, which is higher No bubbles are observed even at a high vacuum of 10 Pa or less. Thus, the pressure which suppresses bubble generation differs depending on the temperature of the sealing material, and various processing temperatures can be selected. In this embodiment, the temperature of the softening point of the sealing material 104 is 420 ° C. to 440 ° C., and the sealing material 104 is treated at a maximum of about 410 ° C. or less. Accordingly, it is possible to suppress the generation of bubbles when the pressure around the substrate is about several tens of kPa, which is a slightly reduced pressure than the atmospheric pressure. Further, since the pressure increases due to degassing due to temperature rise and time, the vacuum pump connected to the exhaust port 111 is controlled so that the pressure inside the vacuum heating furnace 110 is always kept in a reduced pressure state.
[0117]
Furthermore, in order to improve the reliability of maintaining the hermeticity of the sealing material 104, it is important to form the existence ratio of microbubbles existing in the temporarily fired sealing material 104 to a minimum. For this purpose, it is effective to preliminarily perform defoaming firing by high-temperature firing or firing atmosphere control in addition to optimizing the binder removal profile and the like when the sealing material 104 is temporarily fired.
[0118]
Next, in order to further soften the sealing material 104, the PDP 100 is held at a temperature in the vicinity of 400 ° to 410 ° C. (period T4 in FIG. 12). This time T4 is only the time required for the deformation of the sealing material 104, and is about several minutes to several tens of minutes in this embodiment.
[0119]
Next, the process proceeds to the cooling process of the PDP 100 (period T5 to T6 in FIG. 12), and the furnace is evacuated again at about 350 ° to 400 ° C where the sealing material 104 is solidified, and the temperature is lowered to room temperature while maintaining a high vacuum. To do.
[0120]
Next, the elevating seal head 112 is mounted so as to cover the through hole 115 and the entire molded glass frit 119.
[0121]
The structure of the elevating seal head 112 will be described with reference to FIG. A vacuum seal 114 is provided at a portion where the elevating seal head 112 and the rear glass substrate 102 are in contact with each other in order to maintain a vacuum. The vacuum heating furnace 110 has a structure in which the vacuum heating furnace 110 is kept airtight by press-contacting the elevating seal head 112 to the rear glass substrate 102 by the vacuum seal 114. Further, the elevating seal head 112 is provided with an exhaust / gas introduction pipe 116 for filling exhaust gas and discharge gas. The exhaust / gas introduction pipe 116 is connected to a vacuum pump (not shown) or each gas cylinder constituting the discharge gas filling the discharge space 103 via a switching valve. Further, the elevating seal head 112 is provided with a quartz glass window 118, and infrared light from an infrared irradiation lamp 117 can be irradiated to the molded glass frit 119 through the quartz glass window 118. Yes.
[0122]
The inside of the discharge space 103 is once evacuated, preferably via the exhaust / gas introduction pipe 116, with the elevating seal head 112 lowered until the vacuum seal 114 is in close contact with the back glass substrate 102. Thereafter, the discharge space 103 is filled with a predetermined discharge gas. Next, infrared light is irradiated from an infrared irradiation lamp 117 through a quartz glass window 118 toward a molded glass frit 119 using a material having a high infrared absorption rate, and the molded glass frit 119 is melted to form a through hole. 115 is sealed.
[0123]
In the fifth embodiment, utilizing the fact that the height of the sealing material 104 is higher than that of the partition wall 20, a gap 105 is generated between one substrate and the sealing material 104 when the glass substrates 101 and 102 are overlapped. In addition, a process for removing the impurities in the gap 105 by evacuating the periphery of the substrate pair by vacuum evacuation until the sealing material 104 is melted is added. Therefore, it is possible to prevent the discharge space 103 from being contaminated. It is also possible to remove impurities in the discharge space 103 at a stage that has not yet been sealed.
[0124]
In addition, a material having a high softening point temperature is used as the sealing material 104, so that the impurity gas can be removed to the highest possible temperature before the sealing material 104 is fused, and impurities can be removed more reliably. The operating characteristics of the plasma display panel can be improved.
[0125]
Furthermore, since impurities can be efficiently removed, the exhaust time at high temperatures can be shortened. Further, in this embodiment, since the discharge space 103 is exhausted and filled with discharge gas without using a conducting tube, there is no need to pay attention to breakage of the conducting tube. It also has the effect of being easy to transport, handle and install.
[0126]
Next, a sixth embodiment is shown in FIGS. The sixth embodiment is a method that can be easily installed as a mass production method. FIG. 13 is a diagram showing the state of the processing steps of the PDP 130 including the substrate pairs 101 and 102, and FIG. 14 is a diagram showing the processing cycle. Members having the same functions as those of the first to fifth embodiments are denoted by the same reference numerals and description thereof is omitted.
[0127]
In the sixth embodiment, it is possible to limit the application of a large-scale vacuum heating furnace in a series of steps to a partial period, and the conventional through-hole sealing method is also possible. Since the same method can be adopted, it has a feature that can be handled with relatively easy equipment.
[0128]
The front glass substrate 101 and the rear glass substrate 102 are formed in the same manner as in the fifth embodiment. Similar to the fifth embodiment, the front glass substrate 101 and the rear glass substrate 102 are overlapped and fixed by a plurality of clips 7. The clip 7 is tightened in the same manner as in the fifth embodiment.
[0129]
The vacuum heating furnace 140 to be used is heated by a heater (not shown), and the inside of the furnace can be exhausted by a vacuum pump (not shown) connected via an exhaust port 141 to be in a high vacuum state. It is.
[0130]
Next, the molded glass frit 131 having a through hole and the flared conducting tube 132 are fixed by pressing the flared portion with the clip 7 ′. The clip tip of the clip 7 ′ is provided with a U-shaped notch to avoid the tubular portion of the conducting tube 132 and press the flared portion. A seal head 133 is attached to the tip of the conducting tube 132 that is not flared. The seal head 133 used here is provided with a resin capable of maintaining a vacuum by press-contacting in a direction in which the conducting tube 132 is tightened from the periphery. The heat resistance of this resin is about 200 ° C., and a cooling water pipe 135 for circulating the cooling water is provided in the seal head 133 in order to cool the entire resin.
[0131]
Further, the through hole 115 of the rear glass substrate 102 is connected to the exhaust / gas introduction pipe 134 through the hole of the molded glass frit 131 and the conduction pipe 132. The exhaust / gas introduction pipe 134 is connected to a vacuum facility and a facility for supplying discharge gas via a switching valve (not shown).
[0132]
The superposed substrate pair put into the vacuum heating furnace 140 is heated at a rapid temperature increase rate so that the substrate is not damaged up to about 350 ° C. where the change in the substrate performance due to the influence of impure gas hardly occurs (see FIG. 14 T1).
[0133]
Next, by evacuating the inside of the vacuum heating furnace 140, the entire periphery of the superposed substrate pair is evacuated and the substrate temperature is maintained at about 350 ° C. to 370 ° C. (T2 in FIG. 14).
[0134]
At this time, since the sealing material 104 is not melted, the impure gas generated from the substrate is removed from the gap 105 (see FIG. 10) between the sealing material 104 and the front glass substrate 101 as in the fifth embodiment. It can be removed well. The substrate temperature is maintained until the removal of the impure gas is completed.
[0135]
Next, the temperature of the superimposed substrate is raised to 370 ° to 410 ° C. (T3 in FIG. 14). At this time, similarly to the fifth embodiment, the sealing material 104 is sequentially melted and fused, and at the same time, the molded glass frit 131 is melted and the flare portion of the back glass substrate 102 and the conducting tube 132 is also sequentially fused. It is. When fusion with the sealing material 104 and the molded glass frit 131 is completed, the discharge space 103 and the conductive tube 132 formed by the overlapped substrate pair are closed with respect to the exhaust / gas introduction pipe 134 via the seal head 133. The system can be evacuated through the seal head 133.
[0136]
Here, with respect to the pressure in the vacuum heating furnace 140, the pressure in the discharge space 103, which is a closed system, is controlled to a negative pressure, and the pressure in the furnace is constantly pressurized against the substrate. The melted sealing material 104 is deformed by using.
[0137]
In the sixth embodiment, similar to the first to fourth embodiments, the clip 7 that fastens and fixes the stacked substrates weakens the tightening force to the extent that the front glass substrate 101 and the rear glass substrate 102 are not misaligned. Or the number of attachments can be reduced.
[0138]
Further, the periphery of the superimposed substrate is returned to the atmospheric pressure level until the sealing material 104 is completely melted. As a result of this operation, it is possible to take measures against problems caused by enlarging microbubbles present in the sealing material 104 as in the fourth embodiment. In the sixth embodiment, since the inside of the superposed substrate is in a closed system, the inside is not contaminated by impure gas, so the atmosphere is used as the gas introduced to return the inside of the furnace to atmospheric pressure. It becomes possible. Moreover, it becomes possible to process the inert gas and the discharge gas with high purity in an extremely small amount filled in the overlapping substrate. Furthermore, the process after the atmospheric leak (T4 to T6 in FIG. 14) can be processed in the atmospheric heating furnace as in the conventional process.
[0139]
Next, the inside of the stacked substrate is continuously exhausted and held for a certain period of time so that no impure gas remains (T4 in FIG. 14), but most of the impure gas generated from the substrate is before the sealing material 104 is fused. Since it is removed by evacuation from the surroundings, it is possible to shift to the temperature lowering step (T5 in FIG. 14) in a shorter time than the conventional method.
[0140]
In addition, as in the fifth embodiment, since inert gas or the like that passes through the vacuum heating furnace 140 is not introduced into the overlapped substrate, there are few problems due to contamination of the inert gas, and the yield is also advantageous. Become.
[0141]
Next, as in the fifth embodiment, the temperature is lowered (T6 in FIG. 14) until the stacked substrate reaches room temperature, and the discharge gas is filled through the seal head 133 and the conducting tube 132. Next, the conducting tube 132 is cut off to complete the panel.
[0142]
According to the sixth embodiment, the glass substrate can be held with weak clamping, and impurities in the discharge space 103 can be sufficiently removed. Furthermore, in a series of processes, it is possible to limit the application of a vacuum heating furnace that is large in scale to a limited part period (T2 to T3 in FIG. 14) of about 350 ° to 410 ° C, Further, since the same method as the conventional method can be adopted for the sealing method of the through hole 115, it can be handled with relatively easy equipment and the reliability is improved.
[0143]
Next, a seventh embodiment is shown in FIGS. In this embodiment, the PDP 130 used in the sixth embodiment is used. FIG. 15 is a diagram illustrating a state of a processing process of the PDP 130 including the substrate pair 101 and 102, and FIG. 16 is a diagram illustrating a processing cycle. FIG. 17 shows details of the seal head, and FIG. 18 shows the operation of the seal head. Members having the same functions as those of the first to sixth embodiments are denoted by the same reference numerals, and description thereof is omitted.
[0144]
In the seventh embodiment, it is not necessary to always attach the seal head 150 to the conducting tube 132 as in the sixth embodiment, and the periphery of the pair of substrates only during a necessary period as in the same embodiment. Is a manufacturing method that satisfies both of the points that should be made high vacuum.
[0145]
The front glass substrate 101 and the rear glass substrate 102 are formed in the same manner as in the fifth embodiment. Similar to the fifth embodiment, the front glass substrate 101 and the rear glass substrate 102 are overlapped and fixed by a plurality of clips 7. The clip 7 is tightened in the same manner as in the fifth embodiment.
[0146]
Next, similarly to the sixth embodiment, the formed glass frit 131 and the conducting tube 132 subjected to the flaring process are fixed by the clip 7 ′. Unlike the fifth embodiment, the leading end of the conducting tube 132 that is not subjected to flare processing is in an open state.
[0147]
Next, the superposed substrate pair is put into a vacuum heating furnace 160 and heated (T1 in FIG. 16). The temperature is raised at a rapid temperature increase rate that does not cause the substrate damage up to about 350 ° C. where the substrate performance hardly changes due to the impure gas.
[0148]
Next, the entire periphery of the superimposed substrate is evacuated. The temperature of the superimposed substrate is maintained at about 350 ° to 370 ° C. (T2 in FIG. 16).
[0149]
At this time, since the sealing material 104 is not melted, it is possible to efficiently remove the impure gas generated from the front and back glass substrates 101 and 102 as in the fifth and sixth embodiments. The substrate temperature is maintained until the removal of the impure gas is completed (T2 in FIG. 16).
[0150]
Next, the temperature of the superimposed substrate is raised to 370 ° C. to 410 ° C. (T3 in FIG. 16). At this time, as in the sixth embodiment, the sealing material 104 is sequentially melted and fused, and at the same time, the molded glass frit 131 is melted and the back glass substrate 102 and the flare portion of the conductive tube 132 are fused. Done.
[0151]
Next, as in the sixth embodiment, until the sealing material 104 is completely melted, the pressure around the overlapped substrate is increased by the inert gas or the discharge gas introduced through the exhaust / gas introduction pipe 151. Let As a result, as in the fourth and fifth embodiments, it is possible to take measures against problems caused by enlarging microbubbles present in the sealing material 104.
[0152]
Next, the temperature is lowered to a temperature at which the sealing material 104 is solidified (T5 in FIG. 16), and exhaust from the periphery of the superimposed substrate is started again. By this exhaust, the slight impurity gas generated during the period T4 in FIG. 16 is more reliably removed. Further, if necessary, the temperature is kept constant at T5 in FIG. 16 to perform more reliable impurity gas removal.
Next, cooling is performed (T6 in FIG. 16). For the purpose of improving the cooling efficiency, a discharge gas that does not contain an impure gas is filled into the vacuum heating furnace 160 through the exhaust / gas introduction pipe 151. Also good.
[0153]
Next, after the temperature of the superposed substrate is lowered to room temperature, the seal head 150 is lowered by an elevating mechanism (not shown) and attached to the conductive tube 132. Details of the seal head 150 will be described with reference to FIGS.
[0154]
High pressure air is supplied to the driving air piping 170 of the seal head 150 from an air supply source (not shown) via a valve. The high-pressure air is supplied to an O-ring 172 provided on the side wall of the cylindrical portion 171 by an internal pipe, and the inner diameter of the O-ring 172 can be made variable. An exhaust / gas introduction pipe 173 is provided on the top wall of the cylindrical portion 171. On the other hand, a heater 174 for fusing and sealing a part of the conducting tube 132 is provided at the tip of the lower L-shaped portion of the seal head 150.
[0155]
Next, the operation of the seal head will be described with reference to FIG. 18A shows a state before the seal head 150 is lowered, and FIG. 18B shows a state when the seal head 150 is attached to the conducting tube 132. FIG. Shows a state in which the seal head 150 returns to the position (A) after the discharge space is filled with a predetermined gas through the seal head 150 and the conducting tube 132 is sealed with the heater 174.
[0156]
Air is supplied to the O-ring 172 at a position where the seal head 150 is lowered, and the inner diameter portion of the O-ring 172 and the conducting tube 132 are brought into close contact with each other ((B) in FIG. 18). With this close contact, the discharge space 103 is connected to the exhaust / gas introduction pipe 173 via the cylindrical portion 171. Next, after the gas introduced at the time of cooling is exhausted by a vacuum pump (not shown) connected to the exhaust / gas introduction pipe 173, the discharge gas is passed through the exhaust / gas introduction pipe 173, the seal head 150, and the conducting pipe 132. Then, the discharge space 103 is filled until a predetermined pressure is reached. Here, when the discharge gas is used as the cooling gas, only the charging pressure of the discharge gas is adjusted.
[0157]
After this filling, the heater 174 is energized to fuse and seal a portion of the conducting tube 132 as described above, and the seal head 150 is raised ((C) in FIG. 18). When the heater 174 melts a part of the conducting tube 132, the outer periphery of the pair of substrates or the vicinity of the melted portion is made higher than the internal pressure of the discharge space so that the point melted portion is easily deformed in the tube diameter inner direction. It may be held.
[0158]
In this embodiment, in addition to the effect of eliminating impurities in the fifth and sixth embodiments, there is no need to always attach the seal head 133 to the conducting tube 132 as in the sixth embodiment. It is easy to transport, and since the seal head is used only near room temperature, the generation of impure gas from the seal head can be avoided, and it is a relatively easy facility that does not require the use of high temperature resistant materials. It can be handled and reliability is improved.
[0159]
The seal head 150 used in the seventh embodiment can also be used in the sixth embodiment by using heat-resistant parts or a structure for circulating cooling water. Similarly, since there is no need to always attach and place, there is an effect that transportation of the superposed substrate becomes easy.
[0160]
【The invention's effect】
According to the method for manufacturing a plasma display panel of the present invention, the sealing material is melted in a state where the pressure between the pair of substrates is reduced, so that the pair of substrates are drawn while crushing the sealing material due to the pressure difference between the inside and the outside. In this way, sealing is performed. In addition, since it is not necessary to apply pressure to the substrate from the outside, the substrate can be sealed without stress, and the time for sealing the pair of substrates with the sealing material can be greatly shortened. Moreover, the installation time of the jig for applying pressure from the outside is also shortened, and mass productivity can be improved.
[0161]
Furthermore, when a plurality of PDPs are obtained from a single substrate, a sealing material is provided at the central portion of the substrate, but this central portion can also be reliably sealed without using a jig. It becomes.
[0162]
Furthermore, according to the present invention, impurities in the discharge space are removed through the gap between the sealing material and the substrate, so that impurities in the discharge space can be more reliably removed and impurities generated from the sealing material can be removed from the discharge space. It is possible to improve the operating characteristics and display characteristics of the plasma display panel, including the light emission characteristics (color temperature) of the phosphor.
[Brief description of the drawings]
FIG. 1 is a diagram showing a basic processing cycle of the present invention.
FIG. 2 is a diagram showing a state during a sealing process according to the present invention.
FIG. 3 is a PDP sectional view showing a sealing step according to the first embodiment of the present invention.
FIG. 4 is a perspective view of a rear glass substrate according to the first embodiment of the present invention.
FIG. 5 is a diagram showing a processing cycle according to the first embodiment of the present invention.
FIG. 6 is a view showing a modification of the barrier according to the first embodiment of the present invention.
FIG. 7 is a diagram showing a PDP according to a second embodiment of the present invention.
FIG. 8 is a diagram illustrating a PDP according to a third embodiment of the present invention.
FIG. 9 is a diagram showing a processing cycle according to a fourth embodiment of the present invention.
FIG. 10 is a diagram showing a state in which glass substrate pairs according to a fifth embodiment of the present invention are overlaid.
FIG. 11 is a diagram showing a state during a sealing process according to a fifth embodiment of the present invention.
FIG. 12 is a diagram showing a processing cycle according to a fifth embodiment of the present invention.
FIG. 13 is a view showing a state during a sealing step according to a sixth embodiment of the present invention.
FIG. 14 is a diagram showing a processing cycle according to a sixth embodiment of the present invention.
FIG. 15 is a view showing a state during a sealing step according to a seventh embodiment of the present invention.
FIG. 16 is a diagram showing a processing cycle according to a seventh embodiment of the present invention.
FIG. 17 is a view showing details of a seal head according to a seventh embodiment of the present invention.
FIG. 18 is a diagram showing an operation of a seal head according to a seventh embodiment of the present invention.
FIG. 19 is a perspective view for explaining the structure of a PDP.
FIG. 20 is a diagram illustrating a state during a sealing process according to a conventional technique.
FIG. 21 is a diagram showing a conventional processing cycle.
[Explanation of symbols]
1, 11, 31, 41, 100, 130 PDP
2, 12, 32, 42, 101 Front glass substrate
3, 13, 33, 43, 102 Rear glass substrate
4, 14, 34, 44, 104 Sealing material
5, 35, 45, 132 Conducting tube
6,103 discharge space
7 clips
8 Heating furnace
9 Piping
10, 133,150 Seal head
22 Barrier
110,140,160 Vacuum heating furnace

Claims (20)

In a method for manufacturing a plasma display panel having a discharge space sealed with a sealing material between a pair of substrates,
A first step of forming a frame-shaped sealing material on at least one substrate and then superimposing the other substrate on the one substrate via the sealing material;
The superposed pair of substrates is placed in a heating furnace, the space existing between the pair of substrates is evacuated under the heating conditions until the sealing material melts, and the evacuation is continued. A second step of depressurizing the space and heating the heating furnace to a predetermined temperature to melt the sealing material;
A third step of fixing the pair of substrates by solidifying the sealing material and forming a prescribed discharge space;
A fourth step of evacuating the discharge space to remove impurities;
And a fifth step of filling the discharge space with a discharge gas. A method of manufacturing a plasma display panel, comprising: 2. The method for manufacturing a plasma display panel according to claim 1, wherein an exhaust process for reducing the pressure in the space between the substrates and a heat process for melting the sealing material are simultaneously started. 3. The plasma display according to claim 1, wherein a barrier for preventing intrusion of the sealing material in a molten state in the second step is provided in advance in a position near the inside of the sealing material. Panel manufacturing method. In the first step, a plurality of the frame-shaped sealing materials are formed side by side on the substrate, and the second to fifth spaces are formed with respect to the plurality of sealing materials and the plurality of spaces respectively formed by the plurality of sealing materials. The method for manufacturing a plasma display panel according to claim 1, wherein the process is performed. 5. The method of manufacturing a plasma display panel according to claim 1, wherein, in the first step, the peripheral portion of the pair of substrates is sandwiched between clips for temporary fixing. In the manufacturing method of the plasma display panel of Claim 1,
A method of manufacturing a plasma display panel, wherein a clean gas is introduced into the discharge space in the fourth step to wash out impurities in the discharge space. One substrate provided with a plurality of electrodes for generating a discharge between adjacent electrodes on the inner surface, a plurality of color phosphors that emit fluorescence by the discharge on the inner surface, and a predetermined provided to classify the phosphors In the method of manufacturing a plasma display panel in which the other substrate having a pattern partition wall is arranged oppositely and the periphery is sealed,
The step of sealing the periphery of the pair of substrates is a process of arranging a sealing material having a height higher than the partition on the periphery of the other substrate,
A process of evacuating the gap between the opposed substrates under the heating conditions until the pair of substrates are placed in a heating furnace and the sealing material melts;
And a process of heating the heating furnace to a temperature at which the sealing material melts in a state where the gap between the substrates is exhausted and decompressed. In a manufacturing method of a plasma display panel, having a partition wall and a sealing material for maintaining a discharge space in at least one of a pair of substrates, and fusing the pair of substrates with the sealing material,
Forming a frame-shaped sealing material on at least one of the substrates, and superimposing the pair of glass substrates;
A second step of heating and raising the temperature of the pair of stacked substrates and evacuating the outer periphery of the pair of substrates to remove impurities between the substrates;
The melted seal interposed between the pair of substrates by melting the sealant and depressurizing a facing space between the pair of substrates through a through hole previously provided in one of the pair of substrates. A third step of pressing and deforming the material to form a predetermined discharge space determined by the height of the partition;
A fourth step of cooling the pair of substrates and solidifying the sealing material;
A fifth step of filling the discharge space with a discharge gas;
And a sixth step of sealing the through hole used for filling the discharge gas. In the manufacturing method of the plasma display panel of Claim 8,
In the first step, the height of the sealing material is formed to be higher than the height of the partition wall, and the partition wall is formed at a position where a clip that sandwiches and fixes the pair of substrates presses the pair of substrates. The plasma display panel is characterized in that the discharge space is formed by performing the first to third steps in a state where the substrate is warped and stress due to warping of the substrate is applied to the sealing material. Production method. In the manufacturing method of the plasma display panel of Claim 8,
In the third step, the pressure around the pair of substrates is made higher than the pressure in the discharge space, so that the plasma display panel is pressed from the periphery of the pair of substrates toward the discharge space. Manufacturing method. In the manufacturing method of the plasma display panel of Claim 8,
In the third step, a pressure difference between the discharge space and the outer periphery of the pair of substrates is made uniform by closing a portion where the discharge space communicates with the outer periphery of the pair of substrates. A method for manufacturing a plasma display panel. In the manufacturing method of the plasma display panel of Claim 8,
In the second step, evacuation is performed from the outer periphery of the pair of substrates only during a period from the vicinity of the temperature at which degassing from the pair of substrates is activated until the sealing material is fused to the substrate. A method of manufacturing a plasma display panel. In the manufacturing method of the plasma display panel of Claim 8,
A method for manufacturing a plasma display panel, wherein a glass frit having a hole is disposed in advance so that the through hole and the hole communicate with each other, and the hole is sealed in the sixth step. In the manufacturing method of the plasma display panel of Claim 8,
A conductive tube that communicates with the through hole of the substrate is provided, and a seal head that can be evacuated through the conductive tube is disposed, and in the discharge space, the through tube and the seal head are disposed in the third step. A method of manufacturing a plasma display panel, wherein the pressure is reduced by exhausting the gas. In the manufacturing method of the plasma display panel of Claim 8,
In the third step, the temperature around the pair of substrates is set to a temperature lower than the softening point degree of the sealing material so that bubbles existing in the sealing material do not expand. A method for manufacturing a plasma display panel, comprising: In the manufacturing method of the plasma display panel of Claim 8,
After the sealing material is fused, the temperature around the pair of substrates is set to a temperature lower than the softening point temperature of the sealing material so that bubbles existing in the sealing material do not expand. A method of manufacturing a plasma display panel, wherein the plasma display panel is raised. In the manufacturing method of the plasma display panel of Claim 8,
A method of manufacturing a plasma display panel, wherein the third step is performed at a temperature higher than a softening start temperature of the sealing material so that bubbles existing in the sealing material are not expanded. The method of manufacturing a plasma display panel according to claim 14,
In the fifth step, a plasma display panel manufacturing method is characterized in that a discharge gas is introduced into the discharge space through the conducting tube and the seal head. The method of manufacturing a plasma display panel according to claim 18,
The seal head has a heater that heats and melts the conducting tube, and after introducing discharge gas into the discharge space through the conducting tube, the conducting tube is heated by the heater so that a part of the conducting tube is formed. A method for manufacturing a plasma display panel, wherein the discharge space is sealed by melting. The method of manufacturing a plasma display panel according to claim 19,
A method for manufacturing a plasma display panel, wherein when a part of the conducting tube is melted, the pressure around the pair of substrates or in the vicinity of the melting point is made higher than the pressure in the discharge space.

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